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  • 101.
    Knutsson, Axel
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Ullbrand, Jennifer
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Rogström, Lina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Almer, J.
    Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439 USA.
    Jansson, B.
    Seco Tools AB, 737 82 Fagersta, Sweden.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Microstructure evolution during annealing of TiAlN-coatings: A combined in-situ SAXS and phase field study2011Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    This paper describes in detail the microstructure evolution of Ti0.33Al0.67N and Ti0.50Al0.50N coatings during isothermal annealing studied by in-situ small angle x-ray scattering (SAXS) in combination with phase field simulations. We show that the decomposition occurs in two stages consistent with spinodal decomposition. During the initial stage, the phase segregation proceeds with a constant size of AlN- and TiN-rich domains with a radius of ~0.7 nm for 5 and 20 min at 900 and 850 C respectively in the Ti0.50Al0.50N alloy. The length of the initial stage depends on the temperature as well as the composition, and is shorter for the higher Al content coating. Following the initial stage, the AlN- and TiN-rich domains coarsen. The decomposition process is discussed in terms of Gibbs free energy, diffusion, and gradient energies. Scanning transmission electron microscopy and energy dispersive x-ray spectroscopy of the post annealed coatings confirm a decomposed microstructure with coherent domains rich in AlN and TiN of the same size as determined by SAXS.

  • 102.
    Knutsson, Axel
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Ullbrand, Jennifer
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Rogström, Lina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Norrby, Niklas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Almer, Jonathan
    Argonne National Laboratory, Illinois, USA.
    Johansson, Mats P.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Jansson, Bo
    Seco Tools AB, Fagersta, Sweden.
    Magnus, Odén
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Early stage spinodal decomposition and microstructure evolution in TiAlN: A combined in-situ SAXS and phase field studyManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    This paper describes in detail the microstructure and phase evolution in Ti0.33Al0.67N and Ti0.50Al0.50N coatings during isothermal annealing, studied by in-situ small angle x-ray scattering (SAXS), in combination with phase field simulations. We show that the isostructural spinodal decomposition occurs in two stages. During the initial stage, the phase segregation proceeds with a constant size of AlN- and TiN-rich domains with an experimentally measured radius of ~0.7 nm for 5 and 20 min at 900 and 850 °C respectively in the Ti0.50Al0.50N alloy. The length of  the initial stage depends on temperature as well as metal composition, and is shorter for the higher Al-content  coating. After the initial stage, the coherent cubic AlN- and TiN-rich domains coarsen. The coarsening process is kinetically limited by diffusion, which allowed us to estimate the diffusivity and activation energies of the metals to 1.4·10-7 m2s-1 and 3.14 eV at-1 respectively.

  • 103.
    Knutsson, Axel
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Ullbrand, Jennifer
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Rogström, Lina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Norrby, Niklas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Johnson, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Almer, J.
    Advanced Photon Source, Argonne National Laboratory, Argonne, USA.
    Johansson, M.P.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan. Seco Tools AB, Fagersta, Sweden.
    Jansson, B.
    Seco Tools AB, Fagersta, Sweden.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Microstructure evolution during the isostructural decomposition of TiAlN: a combined in-situ small angle x-ray scattering and phase field study2013Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, nr 21Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper describes details of the spinodal decomposition and coarsening in metastable cubic Ti0.33Al0.67N and Ti0.50Al0.50N coatings during isothermal annealing, studied by in-situ small angle x-ray scattering, in combination with phase field simulations. We show that the isostructural decomposition occurs in two stages. During the initial stage, spinodal decomposition, of the Ti0.50Al0.50N alloy, the phase separation proceeds with a constant compositional wavelength of ∼2.8 nm of the AlN- and TiN-rich domains. The time for spinodal decomposition depends on annealing temperature as well as alloy composition. After the spinodal decomposition, the coherent cubic AlN- and TiN-rich domains coarsen. The coarsening rate is kinetically limited by diffusion, which allowed us to estimate the diffusivity and activation energy of the metals to 1.4 × 10−6 m2 s−1 and 3.14 eV at−1, respectively.

  • 104.
    Ku, Nai-Yuan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material.
    Thermal Stability of Zr-Si-N Nanocomposite Hard Thin Films2010Independent thesis Advanced level (degree of Master (Two Years)), 30 poäng / 45 hpOppgave
    Abstract [en]

    Mechanical property and thermal stability of Zr-Si-N films of varying silicon contents deposited on Al2O3 (0001) substrates are characterized. All films provided for characterization were deposited by reactive DC magnetron sputter deposition technique from elemental Zr and Si targets in a N2/Ar plasma at 800 oC. The hardness and microstructures of the as deposited films and post-annealed films up to 1100 oC are evaluated by means of nanoindentation, X-ray diffractometry and transmission electron microscopy. The Zr-Si-N films with 9.4 at.% Si exhibit hardness as high as 34 GPa and a strong (002) texture within which vertically elongated ZrN crystallites are embedded in a Si3N4 matrix. The hardness of these two dimensional nanocomposite films remains stable up to 1000 oC annealing temperatures which is in contrast to ZrN films where hardness degradation occurs already above 800 oC. The enhanced thermal stability is attributed to the presence of Si3N4 grain boundaries which act as efficient barriers to hinder the oxygen diffusion. X-ray amorphous or nanocrystalline structures are observed in Zr-Si-N films with silicon contents > 13.4 at.%. After the annealing treatments, crystalline phases such as ZrSi2, ZrO2 and Zr2O are formed above 1000 oC in the Si-containing films while only zirconia crystallites are observed at 800 oC in pure ZrN films because oxygen acts as artifacts in the vacuum furnace. The structural, compositional and hardness comparison of as-deposited and annealed films reveal that the addition of silicon enhances the thermal stability compared to pure ZrN films and the hardness degradation stems from the formation of oxides at elevated temperatures.

  • 105.
    Kumar Yalamanchili, Phani
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Multiscale materials design of hard coatings for improved fracture resistance and thermal stability2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Physical vapor deposited hard coatings comprised of cubic (c) transition metal (TM)-Al-N, and (TM)-Si-N are the current workhorse materials for a large number of metal cutting and wear resistant applications to fight against the extreme conditions of temperature and stress simultaneously. In spite of a high degree of sophistication in terms of material choice and microstructural design, a lower fracture resistance and limited thermal stability of the coatings remains a technological challenge in the field. The lower fracture resistance of the coating is an inherent material property. Limited thermal stability in the TM-Al-N system is associated with the transformation of metastable c -AlN to its stable wurtzite (w)-AlN phase at a temperature above 900 oC resulting an undesirable hardness drop.

    The current work shows how to overcome these challenges by manipulating the coating material at different length scales, i.e. microstructure, crystal and interface structure, and alloy design. The endeavor of multiscale materials design is achieved by converging a deeper material and process knowledge to result specific structural modification over multiple length scales by alloying transition metal nitrides with AlN and SiNx as following.

    Microstructure variation is achieved in ZrN coating by alloying it with SiNx, where the surface segregated SiNx breaks down the columnar structure and evolves a selforganized nanocomposite structure with a hardness variation from 37 ±2 GPa to 26 ±1 GPa. The indentation induced fracture studies reveal crack deflection for the columnar coating, likely along the column boundaries. The crack deflection offers additional energy dissipative mechanisms that make the columnar structured coating more fracture resistant, which is not the case for the nanocomposite coating in spite of its lower hardness.

    Crystal structure of AlN is varied between stable wurtzite structure to metastable cubic structure in the ZrAlN alloy by adapting a multilayer structure and tuning the layer thickness. The multilayer consisting c-AlN layer shows a hardness of 34 ±1 GPa and a twofold enhancement in the critical force to cause an indentation induced surface crack compared to the multilayer containing w-AlN in spite of a lower hardness for the later case. The higher fracture resistance is discovered to be caused by stress- induced transformation of AlN from its metastable cubic structure to its thermodynamically stable wurtzite structure associated with a molar volume expansion of 20% that builds up local compressive stress zones delaying the onset and propagation of the cracks. This is in fact the first experimental data point for the stress-induced transformation toughening in a hard coating.

    The current work also demonstrates a concept of improving the thermal stability of the TM-Al-N by modifying the interface structure between w-AlN and c-TMN. A popular belief in the field is that AlN in its stable wurtzite structure is detrimental to coating hardness, and hence the current material design strategy is to force AlN in metastable cubic phase that confines the application temperature (~ 900 oC). In contrast, here it is shown that the w-AlN offers a high hardness provided if it is grown (semi-)coherent to c-TMN. This is experimentally shown for the multilayer system of TiN/ZrAlN. The interface structure between the c-TiN, c-ZrN and w-AlN is transformed from incoherent to (semi-)coherent structure by tuning the growth conditions under a favorable crystallographic template. Furthermore, the low energy (semi-) coherent interface structure between w-AlN and c- TiN, c- ZrN display a high thermal stability, causing a high and more stable hardness up to an annealing temperature of 1150 oC with a value of 34± 1.5 GPa. This value is 50 % higher compared to the state-of-the-art monolithic and multilayered Ti-Al-N and Zr-Al-N coating containing incoherent w-AlN.

    Finally, an entropy based alloy design concept is explored to form a thermodynamically stable solid solution in the TM-Al-N material system that has a positive enthalpy of mixing. Multi-principal element alloys of (AlTiVCrNb)N are formed in a near ideal cubic solid solution. The high configurational entropy in the alloy is predicted to overcome positive enthalpy of mixing, there by an entropy stabilized solid solution formation is expected at a temperature above 1000 K. However, at elevated temperature, optimization between the minimization of interaction energy and maximization of configurational randomness causes precipitation of AlN in its stable wurtzite structure and the cubic solid solution is only confined between TiN, CrN, VN and NbN that have a low enthalpy of mixing.

    In summary, this work provides technological solutions to the two outstanding issues in the field. A significant enhancement in fracture resistance of the coating is achieved with appropriate material choice and microstructural design by invoking crack deflection and stress induced transformation toughening mechanisms. A remarkable thermal stability enhancement of the TM-Al-N coating is achieved by a new structural archetype consisting c-TMN and thermodynamically stable w-AlN with a low energy (semi-)coherent interface structure.

    Delarbeid
    1. Structure, deformation and fracture of arc evaporated Zr-Si-N ternary hard films
    Åpne denne publikasjonen i ny fane eller vindu >>Structure, deformation and fracture of arc evaporated Zr-Si-N ternary hard films
    Vise andre…
    2014 (engelsk)Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 258, s. 1100-1107Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Zr-Si-N films with varying Si contents were grown on WC-Co substrates with an industrial scale reactive cathodic arc deposition technique. The microstructural changes correlate to variation in mechanical properties with different deformation mechanisms dominating for different structures. Si forms a substitutional solid solution in the cubic ZrN lattice up to 1.8 at. % in a fine columnar structure. Further Si additions results in precipitation of an amorphous (a)-SiNX phase and evolution of a nanocomposite structure (nc ZrN-a SiNX) which has completely suppressed the columnar structure at 6.3 at. % Si. The rotation-induced artificial layering during film growth was used as a marker to visualize the deformation of the film. A dislocation-based homogeneous plastic deformation mechanism dominates the columnar structure, while grain boundary sliding is the active mechanism mediating heterogeneous plastic deformation in the nanocomposite structure. Film hardness increases with increasing Si content in the columnar structure due to an effective solid solution strengthening. The deformation mechanism of localized grain boundary sliding in the nanocomposite structure results in lower hardness. When cracking is induced by indentation, the fine columnar structure exhibits pronounced crack deflection that results in higher fracture resistance compared to the nanocomposite films.

    sted, utgiver, år, opplag, sider
    Elsevier, 2014
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-106760 (URN)10.1016/j.surfcoat.2014.07.024 (DOI)000346895000134 ()
    Tilgjengelig fra: 2014-05-21 Laget: 2014-05-21 Sist oppdatert: 2018-01-03bibliografisk kontrollert
    2. Tuning hardness and fracture resistance of ZrN/Zr0.63Al0.37N nanoscale multilayers by stress-induced transformation toughening
    Åpne denne publikasjonen i ny fane eller vindu >>Tuning hardness and fracture resistance of ZrN/Zr0.63Al0.37N nanoscale multilayers by stress-induced transformation toughening
    Vise andre…
    2015 (engelsk)Inngår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 89, s. 22-31Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Structure and mechanical properties of nanoscale multilayers of ZrN/Zr0.63Al0.37N grown by reactive magnetron sputtering on MgO (0 0 1) substrates at a temperature of 700 degrees C are investigated as a function of the Zr0.63Al0.37N layer thickness. The Zr0.63Al0.37N undergoes in situ chemical segregation into ZrN-rich and AlN-rich domains. The AlN-rich domains undergo transition from cubic to wurtzite crystal structure as a function of Zr0.63Al0.37N layer thickness. Such structural transformation allows systematic variation of hardness as well as fracture resistance of the films. A maximum fracture resistance is achieved for 2 nm thick Zr0.63Al0.37N layers where the AlN-rich domains are epitaxially stabilized in the metastable cubic phase. The metastable cubic-AlN phase undergoes stress-induced transformation to wurtzite-AlN when subjected to indentation, which results in the enhanced fracture resistance. A maximum hardness of 34 GPa is obtained for 10 nm thick Zr0.63Al0.37N layers where the wurtzite-AlN and cubic-ZrN rich domains form semi-coherent interfaces.

    sted, utgiver, år, opplag, sider
    Elsevier, 2015
    Emneord
    Nitride multilayer thin films; Mechanical properties; Fracture toughness
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-118029 (URN)10.1016/j.actamat.2015.01.066 (DOI)000353249100003 ()
    Merknad

    Funding Agencies|European Unions Erasmus-Mundus graduate school in Material Science and Engineering (DocMASE); Swedish Foundation for Strategic Research (SSF) through the grant Designed Multicomponent Coatings (MultiFilms); Swedish Governmental Agency for Innovation Systems (Vinnova) through the VINN Excellence Centre FunMat; VINNMER Grant [2011-03464]; EU [C/4-EFRE-13/2009/Br]; DFG; federal state government of Saarland [INST 256/298-1 FUGG]

    Tilgjengelig fra: 2015-05-21 Laget: 2015-05-20 Sist oppdatert: 2017-12-04bibliografisk kontrollert
  • 106.
    Kumar Yalamanchili, Phani
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Schramm, Isabella C.
    University of Saarland, Germany.
    Jimenez-Pique, E.
    University of Politecn Cataluna, Spain; CRnE UPC, Spain.
    Rogström, Lina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Muecklich, F.
    University of Saarland, Germany.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Ghafoor, Naureen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Tuning hardness and fracture resistance of ZrN/Zr0.63Al0.37N nanoscale multilayers by stress-induced transformation toughening2015Inngår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 89, s. 22-31Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Structure and mechanical properties of nanoscale multilayers of ZrN/Zr0.63Al0.37N grown by reactive magnetron sputtering on MgO (0 0 1) substrates at a temperature of 700 degrees C are investigated as a function of the Zr0.63Al0.37N layer thickness. The Zr0.63Al0.37N undergoes in situ chemical segregation into ZrN-rich and AlN-rich domains. The AlN-rich domains undergo transition from cubic to wurtzite crystal structure as a function of Zr0.63Al0.37N layer thickness. Such structural transformation allows systematic variation of hardness as well as fracture resistance of the films. A maximum fracture resistance is achieved for 2 nm thick Zr0.63Al0.37N layers where the AlN-rich domains are epitaxially stabilized in the metastable cubic phase. The metastable cubic-AlN phase undergoes stress-induced transformation to wurtzite-AlN when subjected to indentation, which results in the enhanced fracture resistance. A maximum hardness of 34 GPa is obtained for 10 nm thick Zr0.63Al0.37N layers where the wurtzite-AlN and cubic-ZrN rich domains form semi-coherent interfaces.

  • 107.
    Landälv, Ludvig
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Sandvik Coromant AB, Sweden.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Spitz, S.
    Karlsruhe Institute Technology, Germany.
    Leiste, H.
    Karlsruhe Institute Technology, Germany.
    Ulrich, S.
    Karlsruhe Institute Technology, Germany.
    Johansson-Jöesaar, Mats P
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. SECO Tools AB, Sweden.
    Ahlgren, M.
    Sandvik Coromant AB, Sweden.
    Gothelid, E.
    Sandvik Coromant AB, Sweden.
    Alling, Björn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten. Max Planck Institute Eisenforsch GmbH, Germany.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Stueber, M.
    Karlsruhe Institute Technology, Germany.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Structural evolution in reactive RF magnetron sputtered (Cr,Zr)2O3 coatings during annealing2017Inngår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 131, s. 543-552Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reactive RF-magnetron sputtering is used to grow Cr0.28Zr0.10O0.61 coatings at 500 degrees C. Coatings are annealed at 750 degrees C, 810 degrees C, and 870 degrees C. The microstructure evolution of the pseudobinary oxide compound is characterized through high resolution state of the art HRSTEM and HREDX-maps, revealing the segregation of Cr and Zr on the nm scale. The as-deposited coating comprises cc-(Cr,Zr)(2)O-3 solid solution with a Zr-rich (Zr,Cr)O-x. amorphous phase. After annealing to 750 degrees C tetragonal ZrO2 nucleates and grows from the amorphous phase. The ZrO2 phase is stabilized in its tetragonal structure at these fairly low annealing temperatures, possibly due to the small grain size (below 30 nm). Correlated with the nucleation and growth of the tetragonal-ZrO2 phase is an increase in hardness, with a maximum hardness after annealing to 750 degrees C, followed by a decrease in hardness upon coarsening, bcc metallic Cr phase formation and loss of oxygen, during annealing to 870 degrees C. The observed phase segregation opens up future design routes for pseudobinary oxides with tunable microstructural and mechanical properties. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  • 108.
    Larsson, Arvid
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Moskalenko, Evgenii
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Larsson, Mats
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Holtz, Per-Olof
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Charge state control of single InAs/GaAs quantum dots by means of an external magnetic field2008Inngår i: in PHYSICS OF SEMICONDUCTORS, vol 1199, AIP , 2008, s. 297-298Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Individual InAs/GaAs quantum dots (QDs) are studied with micro-photoluminescence in the presence of an applied external magnetic field. Attention is focused on the redistribution between the spectral lines of a single QD observed at increased external magnetic field when the magnetic field is applied parallel to the growth direction (Faraday geometry). The effect is shown to be transport related as the electron drift velocity in the QD-plane is decreased by the applied magnetic field and this affects the probability for electron capture into the QD.

  • 109.
    Lauridsen, Jonas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Knutsson, A
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Mannerbro, R
    ABB Components, Sweden.
    Andersson, A M
    ABB Corp Research.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Microstructural and Chemical Analysis of AgI Coatings Used as a Solid Lubricant in Electrical Sliding Contacts2012Inngår i: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 46, nr 2, s. 187-193Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    AgI coatings have been deposited by electroplating on Ag-plated Cu coupons. Electron microscopy shows that the coatings consist of weakly agglomerated AgI grains. X-ray diffraction, differential scanning calorimetry, thermogravimetry, and mass spectrometry show that the AgI exhibits a reversible transformation from hexagonal to cubic phase at 150 A degrees C. AgI starts to decompose at 150 A degrees C with an accelerating rate up to the AgI melting temperature (555 A degrees C), where a complex-bonded hydroxide evaporates. Ag pin-on-disk testing shows that the iodine addition to Ag decreases the friction coefficient from 1.2 to similar to 0.4. The contact resistance between AgI and Ag becomes less than 100 mu I (c) after similar to 500 operations as the AgI deagglomerates, and Ag is exposed on the surface and remains low during at least 10,000 reciprocating operations. This makes AgI suitable as a solid lubricant in electrical contacts.

  • 110.
    Lauridsen, Jonas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Knutsson, Axel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Mannerbro, R.
    ABB Components, Lyviksvägen 10, SE-771 41, Ludvika, Sweden.
    Andersson, A. M.
    ABB Corporate Research, Forskargränd 7, SE-721 78, Västerås, Sweden.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    AgI as a solid lubricant in electrical contactsManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    AgI coatings have been deposited by electroplating on Ag plated Cu coupons. Electron microscopy shows that the coatings consist of weakly agglomerated AgI grains. X-ray diffraction, differential scanning  calorimetry, thermogravimetry and mass spectrometry show that the AgI exhibits a reversible transformation from hexagonal to cubic phase at 150 °C. AgI starts to decompose at 150 °C with an accelerating rate up to the AgI melting temperature (555 °C), where a complex-bonded  hydroxide evaporates. Ag-pin-on-disk testing shows that the iodine addition to Ag decreases the friction coefficient from 1.2 to ~0.4. The contact resistance between AgI and Ag becomes less than 100 μΩ after ~500 operations as the AgI deagglomerates and Ag is exposed on the surface, and remains low during at least 10000 reciprocating operations. This makes AgI suitable as a solid lubricant in electrical contacts.

  • 111.
    Lebedev, A.A.
    et al.
    Ioffe Physicotechnical Institute, Russian Academy of Sciences, St. Petersburg, 194021, Russian Federation.
    Zelenin, V.V.
    Ioffe Physicotechnical Institute, Russian Academy of Sciences, St. Petersburg, 194021, Russian Federation.
    Abramov, P.L.
    Ioffe Physicotechnical Institute, Russian Academy of Sciences, St. Petersburg, 194021, Russian Federation.
    Lebedev, S.P.
    Ioffe Physicotechnical Institute, Russian Academy of Sciences, St. Petersburg, 194021, Russian Federation.
    Smirnov, A.N.
    Ioffe Physicotechnical Institute, Russian Academy of Sciences, St. Petersburg, 194021, Russian Federation.
    Sorokin, L.M.
    Ioffe Physicotechnical Institute, Russian Academy of Sciences, St. Petersburg, 194021, Russian Federation.
    Shcheglov, M.P.
    Ioffe Physicotechnical Institute, Russian Academy of Sciences, St. Petersburg, 194021, Russian Federation.
    Yakimova, Rositsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Studying 3C-SiC epilayers grown on the (0001)C face of 6H-SiC substrates2007Inngår i: Technical physics letters, ISSN 1063-7850, E-ISSN 1090-6533, Vol. 33, nr 6, s. 524-526Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Epitaxial 3C-SiC films grown on the (0001)C face of 6H-SiC substrates by sublimation epitaxy in vacuum have been studied. The results of x-ray diffraction measurements show evidence of a rather high structural perfection of silicon carbide epilayers. The Raman spectroscopy data confirm that the 3C-SiC layer grows immediately on the 6H-SiC substrate without any transition layers. It is concluded that the structures under consideration are well suited for the investigation of a two-dimensional electron gas at the 3C-SiC/6C-SiC heterojunction. © Nauka/Interperiodica 2007.

  • 112.
    Lind, Hans
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Forsén, Rikard
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik.
    Alling, Björn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Ghafoor, Naureen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Tasnadi, Ferenc
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Johansson, M P
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Abrikosov, Igor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Improving thermal stability of hard coating films via a concept of multicomponent alloying2011Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 99, nr 9, s. 091903-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We propose a design route for the next generation of nitride alloys via a concept of multicomponent alloying based on self-organization on the nanoscale via a formation of metastable intermediate products during the spinodal decomposition. We predict theoretically and demonstrate experimentally that quasi-ternary (TiCrAl)N alloys decompose spinodally into (TiCr)N and (CrAl)N-rich nanometer sized regions. The spinodal decomposition results in age hardening, while the presence of Cr within the AlN phase delays the formation of a detrimental wurtzite phase leading to a substantial improvement of thermal stability compared to the quasi-binary (TiAl)N or (CrAl)N alloys.

  • 113.
    Lind, Hans
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Pilemalm, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Rogström, Lina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Tasnadi, Ferenc
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Ghafoor, Naureen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Forsén, Rikard
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Johnson, Lars
    Sandvik Coromant, Stockholm, Sweden.
    Jöesaar, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan. SECO Tools AB, Fagersta, Sweden.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Abrikosov, Igor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    High temperature phase decomposition in TixZryAlzN2014Inngår i: AIP Advances, ISSN 2158-3226, E-ISSN 2158-3226, Vol. 4, nr 12, s. 127147-1-127147-9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Through a combination of theoretical and experimental observations we study the high temperature decomposition behavior of c-(TixZryAlzN) alloys. We show that for most concentrations the high formation energy of (ZrAl)N causes a strong tendency for spinodal decomposition between ZrN and AlN while other decompositions tendencies are suppressed. In addition we observe that entropic  effects due to configurational disorder favor a formation of a stable Zr-rich (TiZr)N phase with increasing temperature. Our calculations also predict that at high temperatures a Zr rich (TiZrAl)N disordered phase should become more resistant against the spinodal decomposition despite its high and positive formation energy due to the specific topology of the free energy surface at the relevant concentrations. Our experimental observations confirm this prediction by showing strong tendency towards decomposition in a Zr-poor sample while a Zr-rich alloy shows a greatly reduced decomposition rate, which is mostly attributable to binodal decomposition processes. This result highlights the importance of considering the second derivative of the free energy, in addition to its absolute value in predicting decomposition trends of thermodynamically unstable alloys.

  • 114.
    Maistro, G.
    et al.
    Chalmers, Sweden.
    Oikonomou, C.
    Chalmers, Sweden; Uddeholms AB, Sweden.
    Rogström, Lina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Nyborg, L.
    Chalmers, Sweden.
    Cao, Y.
    Chalmers, Sweden.
    Understanding the microstructure-properties relationship of low-temperature carburized austenitic stainless steels through EBSD analysis2017Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 322, s. 141-151Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present article is dedicated to the microstructural characterization of the surface layer of two different austenitic stainless steels, 304L and 9041, subjected to a low-temperature carburizing process (Kolsterising (R), Bodycote) and a subsequent annealing at high-temperature. The carburizing treatment forms a hard expanded austenite in both materials. However, thermal decomposition occurs at high temperatures through precipitation of chromium-carbides, hence compromising the surface hardness of the treated materials. The purpose of this paper is to explore the potential applicability of electron backscatter diffraction (EBSD) technique to reveal the correlation between phase transformation and hardness. First of all, EBSD was used to create kernel average misorientation (KAM) maps of the modified surface layers to identify the internal strains. Moreover, the preferential sites for precipitation of chromium-compound during annealing were identified. We prove here that EBSD can provide useful information to distinguish the main hardening mechanisms within modified surface layers at different annealing conditions. When combined with nano-indentation, X-ray diffraction (XRD) and glow discharge optical emission spectrometry (GDOES), an effective bridge between macro and microanalysis can be obtained. Solid solution hardening was found to be the dominant mechanism in as-carburized materials, with pre-existing strain promoting a higher supersaturation. In the annealed materials, the alloy composition and surface finish can also dictate the preferential sites of precipitation and can therefore affect the residual hardening. (C) 2017 Elsevier B.V. All rights reserved.

  • 115.
    Molina-Aldareguia, J.M.
    et al.
    Dept. of Mat. Sci. and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, United Kingdom.
    Lloyd, S.J.
    Dept. of Mat. Sci. and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, United Kingdom.
    Odén, Magnus
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material.
    Joelsson, Torbjörn
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Hultman, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Clegg, W.J.
    Dept. of Mat. Sci. and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, United Kingdom.
    Deformation structures under indentations in TiN/NbN single-crystal multilayers deposited by magnetron sputtering at different bombarding ion energies2002Inngår i: Philosophical magazine. A. Physics of condensed matter. Defects and mechanical properties, ISSN 0141-8610, Vol. 82, nr 10 SPEC., s. 1983-1992Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Work elsewhere has suggested that multilayer films with layer thicknesses of a few nanometres can be much harder than monolithic films, although there is considerable variation in the observed magnitude of this effect. To investigate this, multilayer TiN/NbN films have been deposited by reactive magnetron sputtering on to MgO single crystals. The hardnesses measured were similar to those of the TiN and NbN alone, which is consistent with the observation by transmission electron microscopy (TEM) that deformation across the interfaces was not prevented. Varying the electrical potential at which the film was grown from -10 to -200 V and the corresponding ion energy from 10 to 200 eV increased the hardness from 19 to 25 GPa, further decreases in the potential caused the hardness to decrease. Using TEM, deformation was observed to occur along the apparent columnar boundaries within the films, suggesting that the effect of the electrical potential on the measured hardness was caused by changes in the apparent strength of the columnar boundaries, possibly associated with the variations in the volume fraction of voids that were observed on these boundaries.

  • 116.
    Moverare, Johan
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Konstruktionsmaterial. Linköpings universitet, Tekniska högskolan.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Influence of Microstresses on Anisotropic High Cycle Fatigue Behaviour of Duplex Stainless Steels2002Inngår i: Proc. 8th International Fatigue Congress, 2002, s. 541-548Konferansepaper (Annet vitenskapelig)
  • 117.
    MSaoubi, R.
    et al.
    Seco Tools AB, Sweden.
    Alm, O.
    Seco Tools AB, Sweden.
    Andersson, J. M.
    Seco Tools AB, Sweden.
    Engstrom, H.
    Seco Tools AB, Sweden.
    Larsson, T.
    Seco Tools AB, Sweden.
    Johansson-Joesaar, M. P.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Seco Tools AB, Sweden.
    Schwind, M.
    Seco Tools AB, Sweden.
    Microstructure and wear mechanisms of texture-controlled CVD alpha-Al2O3 coatings2017Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 376, s. 1766-1778Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the present study, the microstructure and wear mechanisms of texture controlled CVD alpha-Al2O3 layers with (001), (012) and (100) growth textures were investigated in single point turning of C45 carbon steel at low and high cutting speeds. The experimental coatings were investigated by FEG-SEM, EBSD and a combination of FIB and analytical TEM techniques prior to and after machining. Significant texture effects on wear performance of the alpha-Al2O3 coating layers were observed, confirming results from previous wear studies in the context of machining AISI 4140 carbon steel. The wear mechanisms of the coating layers were further interpreted in the light of thermal, mechanical and frictional conditions occurring at the tool chip contact interface. Possible deformation mechanisms of the alpha-Al2O3 layers under the conditions of high pressure and temperatures acting on the tool surface are discussed. The high dislocation density revealed by the TEM observations in the subsurface alpha-Al2O3 layers was attributed to the activation of a basal slip deformation mechanism resulting from the combined action of the shear stress field and high temperature acting on the tool surface. It is suggested that the enhanced and more uniform near surface deformation capability of (001) alpha-Al2O3 is responsible for the improved machining performance. (C) 2017 Elsevier B.V. All rights reserved.

  • 118.
    Mutschler, Anna
    et al.
    Ulm Univ, Germany.
    Stock, Vivian
    Ulm Univ, Germany.
    Ebert, Lena
    Ulm Univ, Germany.
    Björk, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Ulm Univ, Germany.
    Leopold, Kerstin
    Ulm Univ, Germany.
    Linden, Mika
    Ulm Univ, Germany.
    Mesoporous Silica-gold Films for Straightforward, Highly Reproducible Monitoring of Mercury Traces in Water2019Inngår i: NANOMATERIALS, ISSN 2079-4991, Vol. 9, nr 1, artikkel-id 35Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Trace-level detection of mercury in waters is connected with several complications including complex multistep analysis routines, applying additional, harmful reagents increasing the risk of contamination, and the need for expensive analysis equipment. Here, we present a straightforward reagent-free approach for mercury trace determination using a novel thin film sampling stick for passive sampling based on gold nanoparticles. The nanoparticles supported on a silicon wafer and further covered with a thin layer of mesoporous silica. The mesoporous silica layer is acting as a protection layer preventing gold desorption upon exposure to water. The gold nanoparticles are created by thermal treatment of a homogenous gold layer on silicon wafer prepared by vacuum evaporation. This gold-covered substrate is subsequently covered by a layer of mesoporous silica through dip-coating. Dissolved mercury ions are extracted from a water sample, e.g., river water, by incorporation into the gold matrix in a diffusion-controlled manner. Thus, the amount of mercury accumulated during sampling depends on the mercury concentration of the water sample, the accumulation time, as well as the size of the substrate. Therefore, the experimental conditions can be chosen to fit any given mercury concentration level without loss of sensitivity. Determination of the mercury amount collected on the stick is performed after thermal desorption of mercury in the gas phase using atomic fluorescence spectrometry. Furthermore, the substrates can be re-used several tens of times without any loss of performance, and the batch-to-batch variations are minimal. Therefore, the nanogold-mesoporous silica sampling substrates allow for highly sensitive, simple, and reagent-free determination of mercury trace concentrations in waters, which should also be applicable for on-site analysis. Successful validation of the method was shown by measurement of mercury concentration in the certified reference material ORMS-5, a river water.

  • 119.
    Nguyen, Son Tien
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Ivanov, Ivan Gueorguiev
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Kuznetsov, A.
    Svensson, B.G.
    Zhao, Q.X.
    Willander, Magnus
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Morishita, M.N.
    Ohshirma, T.
    Itoh, H.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Yakimova, Rositsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Common point defects in as-grown ZnO substrates studied by optical detection of magnetic resonance2008Inngår i: Journal of Crystal Growth, Vol. 310, 2008, Vol. 310, nr 5, s. 1006-1009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Defects in as-grown commercial zinc oxide (ZnO) substrates were studied by photoluminescence and optical detection of magnetic resonance (ODMR). In addition to the Zn vacancy and shallow donor centers, we observed several ODMR centers with spin S=1/2, labeled LU1-LU4. Among these, the axial LU3 and non-axial LU4 centers were detected in all studied samples. The ODMR signals of LU3/LU4 were found to be drastically increased after electron irradiation. The preliminary result indicates that these common ODMR centers in as-grown ZnO are related to intrinsic defects. © 2007 Elsevier B.V. All rights reserved.

  • 120.
    Norrby, Niklas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    High pressure and high temperature behavior of TiAlN2012Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This licentiate thesis mainly reports about the behavior of arc evaporated TiAlN at high pressures and high temperatures. The extreme conditions have been obtained in metal cutting, multi anvil presses or diamond anvil cells. Several characterization techniques have been used, including x-ray diffraction and transmission electron microscopy.

    Results obtained during metal cutting show that the coatings are subjected to a peak normal stress in the GPa region and temperatures around 900 °C. The samples after metal cutting are shown to have a stronger tendency towards the favorable spinodal decomposition compared to heat treatments at comparable temperatures. We have also shown an increased anisotropy of the spinodally decomposed domains which scales with Al composition and results in different microstructure evolutions. Furthermore, multi anvil press and diamond anvil cell at even higher pressures and temperatures (up to 23 GPa and 2200 °C) also show that the unwanted transformation of cubic AlN into hexagonal AlN is suppressed with an increased pressure and/or temperature.

    Delarbeid
    1. Pressure and temperature effects on the decomposition of arc evaporated Ti0.6Al0.4N coatings during metal cutting
    Åpne denne publikasjonen i ny fane eller vindu >>Pressure and temperature effects on the decomposition of arc evaporated Ti0.6Al0.4N coatings during metal cutting
    2012 (engelsk)Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 209, s. 203-207Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The isostructural decomposition of arc evaporated Ti0.6Al0.4N coatings at the elevated temperatures and high stresses occurring during metal cutting have been studied. Comparisons are made with short time (t=10 min) anneals at temperatures typical for steel turning operations. The evolution of the decomposed domain sizes are studied by analytical transmission electron microscopy from samples originating from the rake face. Temperature and force measurements during turning allowed for separation of the effects of the temperature and stresses on domain size evolution. The results show a peak temperature of around 900 °C and a peak normal stress of around 2 GPa during cutting. The overall domain size is larger after cutting compared to the annealed sample at the same temperature. The results suggest that pressures generated during cutting promote coherent isostructural decomposition which is in line with theoretical studies but for considerably higher pressures.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-78825 (URN)10.1016/j.surfcoat.2012.08.068 (DOI)000310656200029 ()
    Merknad

    Funding Agencies|Swedish Foundation for Strategic Research (SSF) project Designed Multicomponent Coatings, Multifilms||

    Tilgjengelig fra: 2012-06-21 Laget: 2012-06-21 Sist oppdatert: 2018-01-03bibliografisk kontrollert
    2. High pressure and high temperature stabilization of cubic AlN in Ti0.60Al0.40N
    Åpne denne publikasjonen i ny fane eller vindu >>High pressure and high temperature stabilization of cubic AlN in Ti0.60Al0.40N
    Vise andre…
    2013 (engelsk)Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, nr 5Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In the present work, the decomposition of unstable arc evaporated Ti0.6Al0.4N at elevated temperatures and quasihydrostatic pressures has been studied both experimentally and by first-principles calculations. High pressure and high temperature (HPHT) treatment of the samples was realized using the multi anvil press and diamond anvil cell techniques. The products of the HPHT treatment of Ti0.6Al0.4N were investigated using x-ray diffractometry and transmission electron microscopy. Complimentary calculations show that both hydrostatic pressure and high temperature stabilize the cubic phase of AlN, which is one of the decomposition products of Ti0.6Al0.4N. This is in agreement with the experimental results which in addition suggest that the presence of Ti in the system serves to increase the stability region of the cubic c-AlN phase. The results are industrially important as they show that Ti0.6Al0.4N coatings on cutting inserts do not deteriorate faster under pressure due to the cubic AlN to hexagonal AlN transformation.

    sted, utgiver, år, opplag, sider
    American Institute of Physics (AIP), 2013
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-90201 (URN)10.1063/1.4790800 (DOI)000314746200028 ()
    Merknad

    Funding Agencies|Swedish Foundation for Strategic Research (SSF)||German Research Foundation (DFG)|SPP 1236|

    On the day of the defence day the status of this articla was Manucsript and title of this was High pressure and high temperature behavior of Ti0.60Al0.40N.

    Tilgjengelig fra: 2013-03-21 Laget: 2013-03-21 Sist oppdatert: 2018-01-03
    3. Microstructural anisotropy effects on the metal cutting performance of decomposed arc evaporated Ti1-xAlxN coatings
    Åpne denne publikasjonen i ny fane eller vindu >>Microstructural anisotropy effects on the metal cutting performance of decomposed arc evaporated Ti1-xAlxN coatings
    Vise andre…
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    The spinodal decomposition of cathodic arc evaporated cubic phase c-Ti0.34Al0.66N and c-Ti0.60Al0.40N coatings have been studied before and after continuous turning. By means of analytical transmission electron microscopy, we find that the evolving microstructure of c-Ti0.34Al0.66N, as simultaneously being exposed to high temperature of about 900 °C and high pressure of about 2.5 GPa, spinodally decompose into a spatially periodic, highly oriented and modulated interconnected array of coherent cubic AlN and cubic TiN rich regions along elastic compliant <100> crystal directions. Ti0.60Al0.40N instead decomposes into AlN and TiN rich domains in a more rounded and random microstructure. These effects are both explained by the elastic anisotropy which has earlier been shown to scale with Al content. The different evolving microstructure will lead to a different strengthening mechanism in the coatings during metal cutting and heat treatments, thus a different hardness and wear resistance behaviour.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-78829 (URN)
    Tilgjengelig fra: 2012-06-21 Laget: 2012-06-21 Sist oppdatert: 2018-01-03bibliografisk kontrollert
  • 121.
    Norrby, Niklas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Microstructural evolution of TiAlN hard coatings at elevated pressures and temperatures2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    A typical hard coating on metal cutting inserts used in for example turning, milling or drilling operations is TiAlN. At elevated temperatures, TiAlN exhibits a well characterized spinodal decomposition into coherent cubic TiN and AlN rich domains, which is followed by a transformation from cubic to hexagonal AlN. Using in-situ synchrotron x-ray radiation, the kinetics of the second transformation was investigated in this thesis and the strong temperature dependence on the transformation rate indicated a diffusion based nucleation and growth mechanism. The results gave additional information regarding activation energy of the transformation and the critical wavelength of the cubic domains at the onset of hexagonal AlN. After nucleation and growth, the hexagonal domains showed a striking resemblance with the preexisting cubic AlN microstructure.

    During metal cutting, the tool protecting coating is subjected to temperatures of ~900 ºC and pressure levels in the GPa range. The results in this thesis have shown a twofold effect of the pressure on the decomposition steps. Firstly, the spinodal decomposition was promoted by the applied pressure during metal cutting which was shown by comparisons with annealed samples at similar temperatures. Secondly, the detrimental transformation from cubic to hexagonal AlN was shown to be suppressed at elevated hydrostatic pressures. A theoretical pressure/temperature phase diagram, validated with experimental results, also showed suppression of hexagonal AlN by an increased temperature at elevated pressures.

    The spinodal decomposition during annealing and metal cutting was in this work also shown to be strongly affected by the elastic anisotropy of TiAlN, where the phase separation was aligned along the elastically softer <100> directions in the crystal. The presence of the anisotropic microstructure enhanced the mechanical properties compared to the isotropic case, mainly due to a shorter distance between the c-AlN and c-TiN domains in the anisotropic case. Further improvement of the metal cutting behavior was realized by depositing individual layers with an alternating bias. The individual bias layers exhibited microstructural differences with different residual stress states. The results of the metal cutting tests showed an enhanced wear resistance in terms of both crater and flank wear compared to coatings deposited with a fixed bias.

    Delarbeid
    1. Pressure and temperature effects on the decomposition of arc evaporated Ti0.6Al0.4N coatings during metal cutting
    Åpne denne publikasjonen i ny fane eller vindu >>Pressure and temperature effects on the decomposition of arc evaporated Ti0.6Al0.4N coatings during metal cutting
    2012 (engelsk)Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 209, s. 203-207Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The isostructural decomposition of arc evaporated Ti0.6Al0.4N coatings at the elevated temperatures and high stresses occurring during metal cutting have been studied. Comparisons are made with short time (t=10 min) anneals at temperatures typical for steel turning operations. The evolution of the decomposed domain sizes are studied by analytical transmission electron microscopy from samples originating from the rake face. Temperature and force measurements during turning allowed for separation of the effects of the temperature and stresses on domain size evolution. The results show a peak temperature of around 900 °C and a peak normal stress of around 2 GPa during cutting. The overall domain size is larger after cutting compared to the annealed sample at the same temperature. The results suggest that pressures generated during cutting promote coherent isostructural decomposition which is in line with theoretical studies but for considerably higher pressures.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-78825 (URN)10.1016/j.surfcoat.2012.08.068 (DOI)000310656200029 ()
    Merknad

    Funding Agencies|Swedish Foundation for Strategic Research (SSF) project Designed Multicomponent Coatings, Multifilms||

    Tilgjengelig fra: 2012-06-21 Laget: 2012-06-21 Sist oppdatert: 2018-01-03bibliografisk kontrollert
    2. High pressure and high temperature stabilization of cubic AlN in Ti0.60Al0.40N
    Åpne denne publikasjonen i ny fane eller vindu >>High pressure and high temperature stabilization of cubic AlN in Ti0.60Al0.40N
    Vise andre…
    2013 (engelsk)Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, nr 5Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In the present work, the decomposition of unstable arc evaporated Ti0.6Al0.4N at elevated temperatures and quasihydrostatic pressures has been studied both experimentally and by first-principles calculations. High pressure and high temperature (HPHT) treatment of the samples was realized using the multi anvil press and diamond anvil cell techniques. The products of the HPHT treatment of Ti0.6Al0.4N were investigated using x-ray diffractometry and transmission electron microscopy. Complimentary calculations show that both hydrostatic pressure and high temperature stabilize the cubic phase of AlN, which is one of the decomposition products of Ti0.6Al0.4N. This is in agreement with the experimental results which in addition suggest that the presence of Ti in the system serves to increase the stability region of the cubic c-AlN phase. The results are industrially important as they show that Ti0.6Al0.4N coatings on cutting inserts do not deteriorate faster under pressure due to the cubic AlN to hexagonal AlN transformation.

    sted, utgiver, år, opplag, sider
    American Institute of Physics (AIP), 2013
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-90201 (URN)10.1063/1.4790800 (DOI)000314746200028 ()
    Merknad

    Funding Agencies|Swedish Foundation for Strategic Research (SSF)||German Research Foundation (DFG)|SPP 1236|

    On the day of the defence day the status of this articla was Manucsript and title of this was High pressure and high temperature behavior of Ti0.60Al0.40N.

    Tilgjengelig fra: 2013-03-21 Laget: 2013-03-21 Sist oppdatert: 2018-01-03
    3. Anisotropy effects onmicrostructure and properties in decomposed arc evaporated Ti1-xAlxN coatings during metal cutting
    Åpne denne publikasjonen i ny fane eller vindu >>Anisotropy effects onmicrostructure and properties in decomposed arc evaporated Ti1-xAlxN coatings during metal cutting
    Vise andre…
    2013 (engelsk)Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 235, nr 25, s. 181-185Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Anisotropy effects on the spinodal decomposition in cathodic arc evaporated cubic “phase c-Ti1−xAlxN coatingshave been studied with respect to composition, microstructure and hardness properties before and after a continuousturning operation. Coatings are simultaneously being exposed to both a high temperature and high pressureduring the metal cutting process. As evident from the current results, a high Al content coating, x = 0.66,when exposed to such extreme conditions decomposes into cubic c-AlN and c-TiN-rich domains. In this case,the evolving microstructure comprises interconnected spatially periodic, elongated and coherent cubic c-AlNand c-TiN-rich regions aligned along elastic compliant b100N crystal direction. A significantly different microstructurewith randomly oriented domains is observed for a coating with an elemental composition closer tothe isotropic limit, x = 0.28, exposed under the same conditions. From a coating hardness perspective, thenanoindentation results display a minor age hardening effect for the c-Ti1−xAlxN coating grown at x = 0.28while the coating grown with x = 0.66 exhibits a significant age-hardening effect of about 18%. We concludethat both microstructure and age hardening behavior during spinodal decomposition of c-Ti1−xAlxN correlateto the relative amount ofmetal Ti/Al ratio and consequently to the elastic anisotropy of the as-grown coatingmaterial.These results provide newinsights to the understanding of improvedwear resistance of c-Ti1−xAlxN withAl content during metal cutting.

    sted, utgiver, år, opplag, sider
    Elsevier, 2013
    Emneord
    Cathodic arc evaporation; TiAlN; Anisotropy; Microstructure; Hardness; Metal cutting
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-96400 (URN)10.1016/j.surfcoat.2013.07.031 (DOI)000329596100022 ()
    Forskningsfinansiär
    VINNOVA
    Tilgjengelig fra: 2013-08-19 Laget: 2013-08-19 Sist oppdatert: 2018-01-03
    4. Improved metal cutting performance with biasmodulated textured Ti0.50Al0.50N multilayers
    Åpne denne publikasjonen i ny fane eller vindu >>Improved metal cutting performance with biasmodulated textured Ti0.50Al0.50N multilayers
    2014 (engelsk)Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 257, s. 102-107Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In this work we present the cutting performance of Ti0.50Al0.50N coatings which have been deposited with both a fixed and an alternating bias of -35 V and -70 V together with a Ti0.33Al0.67N reference coating grown at -35 V. The bias-modulated coatings were grown with different bias-layer periods, from 200 to 1200 nm. For the layers deposited with a fixed bias, a transition from a (100) to a (111) preferred orientation was observed with the change in bias from -35 V to -70 V. The coatings grown with an alternating bias, however, showed a (111) preferred orientation with an intensity that slightly depends on bias-layer period. Metal cutting performance in terms of crater and flank wear resistance show an improvement for all bias-layered coatings. This is attributed to a (111) oriented refined grain structure in combination with low residual stresses in the coating.

    sted, utgiver, år, opplag, sider
    Elsevier, 2014
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-106505 (URN)10.1016/j.surfcoat.2014.05.045 (DOI)000344423100013 ()
    Forskningsfinansiär
    VINNOVA
    Tilgjengelig fra: 2014-05-09 Laget: 2014-05-09 Sist oppdatert: 2018-01-03bibliografisk kontrollert
    5. In-situ x-ray scattering study of the cubic to hexagonal transformation of AlN in Ti1-xAlxN
    Åpne denne publikasjonen i ny fane eller vindu >>In-situ x-ray scattering study of the cubic to hexagonal transformation of AlN in Ti1-xAlxN
    Vise andre…
    2014 (engelsk)Inngår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 73, s. 205-214Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In the present work, we have studied the decomposition of arc evaporated Ti0.55Al0.45N and Ti0.36Al0.64N during heat treatment in vacuum by in-situ synchrotron wide angle x-ray scattering primarily to characterize the kinetics of the phase transformation of AlN from the cubic NaCl-structure to the hexagonal wurtzite-structure. In addition, in-situ small angle x-ray scattering measurements were conducted to explore details of the wavelength evolution of the spinodal decomposition, thus providing information about the critical size of the c-AlN rich domains prior to the onset of the h-AlN transformation. We report the fractional cubic to hexagonal transformation of AlN in Ti1-xAlxN as a function of time and extract activation energies between 320 and 350 kJ/mol dependent on alloy composition. The onset of the hexagonal transformation occurs at about 50 K lower temperature in Ti0.36Al0.64N compared to Ti0.55Al0.45N where the high Al content alloy also has a significantly higher transformation rate. A critical wavelength for the cubic domains of about 13 nm was observed for both alloys. Scanning transmission electron microscopy shows a c-TiN/h-AlN microstructure with a striking morphology resemblance to the c-TiN/c-AlN microstructure present prior to the hexagonal transformation.

    sted, utgiver, år, opplag, sider
    Elsevier, 2014
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-106506 (URN)10.1016/j.actamat.2014.04.014 (DOI)000337853100020 ()
    Forskningsfinansiär
    VINNOVA
    Merknad

    On the day of the defence date of the thesis the status of this article was Manuscript.

    Tilgjengelig fra: 2014-05-09 Laget: 2014-05-09 Sist oppdatert: 2018-01-03bibliografisk kontrollert
  • 122.
    Norrby, Niklas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Johansson Jöesaar, Mats P.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan. Seco Tools AB, Fagersta, Sweden.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Improved metal cutting performance with biasmodulated textured Ti0.50Al0.50N multilayers2014Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 257, s. 102-107Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work we present the cutting performance of Ti0.50Al0.50N coatings which have been deposited with both a fixed and an alternating bias of -35 V and -70 V together with a Ti0.33Al0.67N reference coating grown at -35 V. The bias-modulated coatings were grown with different bias-layer periods, from 200 to 1200 nm. For the layers deposited with a fixed bias, a transition from a (100) to a (111) preferred orientation was observed with the change in bias from -35 V to -70 V. The coatings grown with an alternating bias, however, showed a (111) preferred orientation with an intensity that slightly depends on bias-layer period. Metal cutting performance in terms of crater and flank wear resistance show an improvement for all bias-layered coatings. This is attributed to a (111) oriented refined grain structure in combination with low residual stresses in the coating.

  • 123.
    Norrby, Niklas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Johansson, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    M’Saoubi, Rachid
    Seco Tools AB, Fagersta, Sweden.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Pressure and temperature effects on the decomposition of arc evaporated Ti0.6Al0.4N coatings during metal cutting2012Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 209, s. 203-207Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The isostructural decomposition of arc evaporated Ti0.6Al0.4N coatings at the elevated temperatures and high stresses occurring during metal cutting have been studied. Comparisons are made with short time (t=10 min) anneals at temperatures typical for steel turning operations. The evolution of the decomposed domain sizes are studied by analytical transmission electron microscopy from samples originating from the rake face. Temperature and force measurements during turning allowed for separation of the effects of the temperature and stresses on domain size evolution. The results show a peak temperature of around 900 °C and a peak normal stress of around 2 GPa during cutting. The overall domain size is larger after cutting compared to the annealed sample at the same temperature. The results suggest that pressures generated during cutting promote coherent isostructural decomposition which is in line with theoretical studies but for considerably higher pressures.

  • 124.
    Norrby, Niklas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Lind, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Parakhonskiy, G
    University of Bayreuth, Germany .
    Johansson, M P.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Tasnadi, Ferenc
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Dubrovinsky, L S.
    University of Bayreuth, Germany .
    Dubrovinskaia, N
    University of Bayreuth, Germany .
    Abrikosov, Igor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    High pressure and high temperature stabilization of cubic AlN in Ti0.60Al0.40N2013Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, nr 5Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the present work, the decomposition of unstable arc evaporated Ti0.6Al0.4N at elevated temperatures and quasihydrostatic pressures has been studied both experimentally and by first-principles calculations. High pressure and high temperature (HPHT) treatment of the samples was realized using the multi anvil press and diamond anvil cell techniques. The products of the HPHT treatment of Ti0.6Al0.4N were investigated using x-ray diffractometry and transmission electron microscopy. Complimentary calculations show that both hydrostatic pressure and high temperature stabilize the cubic phase of AlN, which is one of the decomposition products of Ti0.6Al0.4N. This is in agreement with the experimental results which in addition suggest that the presence of Ti in the system serves to increase the stability region of the cubic c-AlN phase. The results are industrially important as they show that Ti0.6Al0.4N coatings on cutting inserts do not deteriorate faster under pressure due to the cubic AlN to hexagonal AlN transformation.

  • 125.
    Norrby, Niklas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Rogström, Lina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Johansson Jöesaar, Mats P.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan. Seco Tools AB, Fagersta, Sweden.
    Schell, N.
    Helmholtz-Zentrum Geesthacht (HZG), Geesthacht, Germany.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    In-situ x-ray scattering study of the cubic to hexagonal transformation of AlN in Ti1-xAlxN2014Inngår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 73, s. 205-214Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the present work, we have studied the decomposition of arc evaporated Ti0.55Al0.45N and Ti0.36Al0.64N during heat treatment in vacuum by in-situ synchrotron wide angle x-ray scattering primarily to characterize the kinetics of the phase transformation of AlN from the cubic NaCl-structure to the hexagonal wurtzite-structure. In addition, in-situ small angle x-ray scattering measurements were conducted to explore details of the wavelength evolution of the spinodal decomposition, thus providing information about the critical size of the c-AlN rich domains prior to the onset of the h-AlN transformation. We report the fractional cubic to hexagonal transformation of AlN in Ti1-xAlxN as a function of time and extract activation energies between 320 and 350 kJ/mol dependent on alloy composition. The onset of the hexagonal transformation occurs at about 50 K lower temperature in Ti0.36Al0.64N compared to Ti0.55Al0.45N where the high Al content alloy also has a significantly higher transformation rate. A critical wavelength for the cubic domains of about 13 nm was observed for both alloys. Scanning transmission electron microscopy shows a c-TiN/h-AlN microstructure with a striking morphology resemblance to the c-TiN/c-AlN microstructure present prior to the hexagonal transformation.

  • 126.
    Oden, Magnus
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Rogström, Lina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Knutsson, Axel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Terner, M R
    Luleå University.
    Hedstrom, P
    Lulea University.
    Almer, J
    Argonne National Laboratory.
    Ilavsky, J
    Argonne National Laboratory.
    In situ small-angle x-ray scattering study of nanostructure evolution during decomposition of arc evaporated TiAlN coatings2009Inngår i: APPLIED PHYSICS LETTERS, ISSN 0003-6951, Vol. 94, nr 5, s. 053114-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Small-angle x-ray scattering was used to study in situ decomposition of an arc evaporated TiAlN coating into cubic-TiN and cubic-AlN particles at elevated temperature. At the early stages of decomposition particles with ellipsoidal shape form, which grow and change shape to spherical particles at higher temperatures. The spherical particles grow at a rate of 0.18 A/degrees C while coalescing.

  • 127.
    Odén, Magnus
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material.
    Reverse martensitic transformation and resulting microstructure in a cold rolled metastable austenitic stainless steel2008Inngår i: Steel Research International, ISSN 1611-3683, Vol. 79, nr 6, s. 433-439Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The reverse martensitic transformation in cold-rolled metastable austenitic stainless steel has been investigated via heat treatments performed for various temperatures and times. The microstructural evolution was evaluated by differential scanning calorimetry, X-ray diffraction and microscopy. Upon heat treatment, both diffusionless and diffusion-controlled mechanisms determine the final microstructure. The diffusion reversion from α′-martensite to austenite was found to be activated at about 450°C and the shear reversion is activated at higher temperatures with Af′ ∼600°C. The resulting microstructure for isothermal heat treatment at 650°C was austenitic, which inherits the α′-martensite lath morphology and is highly faulted. For isothermal heat treatments at temperatures above 700°C the faulted austenite was able to recrystallize and new austenite grains with a low defect density were formed. In addition, carbo-nitride precipitation was observed for samples heat treated at these temperatures, which leads to an increasing Ms-temperature and new α′-martensite formation upon cooling.

  • 128.
    Paul, Biplab
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Björk, Emma M.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Kumar, Aparabal
    Materials Science Centre, Indian Institute of Technology, Kharagpur 721302, India.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Nanoporous Ca3Co4O9 Thin Films for Transferable Thermoelectrics2018Inngår i: ACS applied energy materials, ISSN 2574-0962, Vol. 1, nr 5, s. 2261-2268Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The development of high-performance and transferable thin-film thermoelectric materials is important for low-power applications, e.g., to power wearable electronics, and for on-chip cooling. Nanoporous films offer an opportunity to improve thermoelectric performance by selectively scattering phonons without affecting electronic transport. Here, we report the growth of nanoporous Ca3Co4O9 thin films by a sequential sputtering-annealing method. Ca3Co4O9 is promising for its high Seebeck coefficient and good electrical conductivity and important for its nontoxicity, low cost, and abundance of its constituent raw materials. To grow nanoporous films, multilayered CaO/CoO films were deposited on sapphire and mica substrates by rf-magnetron reactive sputtering from elemental Ca and Co targets, followed by annealing at 700 C to form the final phase of Ca3Co4O9. This phase transformation is accompanied by a volume contraction causing formation of nanopores in the film. The thermoelectric propoperties of the nanoporous Ca3Co4O9 films can be altered by controlling the porosity. The lowest electrical resistivity is ~7 mO cm, yielding a power factor of 2.32 × 10-4 Wm-1K-2 near room temperature. Furthermore, the films are transferable from the primary mica substrates to other arbitrary polymer platforms by simple dry transfer, which opens an opportunity of low-temperature use these materials.

  • 129.
    Pilemalm, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    TiAlN-based Coatings at High Pressures and Temperatures2014Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    TiAlN and TiAlN-based coatings that are used of relevance as protection of cutting tool inserts used in metal machining have been studied. All coatings were deposited by reactive cathodic arc evaporation using industrial scale deposition systems. The metal content of the coatings was varied by using different combinations of compound cathodes. The as-deposited coatings were temperature annealed at ambient pressure and in some cases also at high pressure. The resulting microstructure was first evaluated through a combination of x-ray diffraction and transmission electron microscopy. In addition, mechanical properties such as hardness by nanoindentation were also reported.

    TiAlN coatings with two different compositions were deposited on polycrystalline boron nitride substrates and then high pressure high temperature treated in a BELT press at constant 5.35 GPa and at 1050 and 1300 °C for different times.

    For high pressure high temperature treated TiAlN it has been shown that the decomposition is slower at higher pressure compared to ambeint pressure and that no chemical interaction takes place between TiAlN and polycrystalline cubic boron nitride during the experiments. It is concluded that this film has the potential to protect a polycrystalline cubic boron nitride substrate during metal machining due to a high chemical integrity.

    TiZrAlN coatings with different predicted driving forces for spinodal decomposition were furthermore annealed at different temperatures. For this material system it has been shown that for Zr-poor compositions the tendency for phase separation between ZrN and AlN is strong at elevated temperatures and that after spinodal decomposition stable TiZrN is formed.

    Delarbeid
    1. High temperature phase decomposition in TixZryAlzN
    Åpne denne publikasjonen i ny fane eller vindu >>High temperature phase decomposition in TixZryAlzN
    Vise andre…
    2014 (engelsk)Inngår i: AIP Advances, ISSN 2158-3226, E-ISSN 2158-3226, Vol. 4, nr 12, s. 127147-1-127147-9Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Through a combination of theoretical and experimental observations we study the high temperature decomposition behavior of c-(TixZryAlzN) alloys. We show that for most concentrations the high formation energy of (ZrAl)N causes a strong tendency for spinodal decomposition between ZrN and AlN while other decompositions tendencies are suppressed. In addition we observe that entropic  effects due to configurational disorder favor a formation of a stable Zr-rich (TiZr)N phase with increasing temperature. Our calculations also predict that at high temperatures a Zr rich (TiZrAl)N disordered phase should become more resistant against the spinodal decomposition despite its high and positive formation energy due to the specific topology of the free energy surface at the relevant concentrations. Our experimental observations confirm this prediction by showing strong tendency towards decomposition in a Zr-poor sample while a Zr-rich alloy shows a greatly reduced decomposition rate, which is mostly attributable to binodal decomposition processes. This result highlights the importance of considering the second derivative of the free energy, in addition to its absolute value in predicting decomposition trends of thermodynamically unstable alloys.

    sted, utgiver, år, opplag, sider
    American Institute of Physics (AIP), 2014
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-110682 (URN)10.1063/1.4905138 (DOI)000347170100078 ()
    Merknad

    On the day of the defence date the status of this article was Manuscript.

    Tilgjengelig fra: 2014-09-18 Laget: 2014-09-18 Sist oppdatert: 2019-05-07bibliografisk kontrollert
  • 130.
    Rogström, Lina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    High temperature behavior of arc evaporated ZrAlN and TiAlN thin films2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Hard coatings can extend the life time of a tool substantially and enable higher cutting speeds which increase the productivity in the cutting application. The aim with this thesis is to extend the understanding on how the microstructure and mechanical properties are affected by high temperatures similar to what a cutting tool can reach during operation.

    Thin films of ZrAlN and TiAlN have been deposited using cathodic arc-evaporation. The microstructure of as-deposited and annealed films has been studied using electron microscopy and x-ray scattering. The thermal stability has been characterized by calorimetry and thermogravity and the mechanical properties have been investigated by  nanoindentation.

    The microstructure of Zr1−xAlxN thin films was studied as a function of composition, deposition conditions, and annealing temperature. The structure was found to depend on the Al content where a low (x < 0.38) Al-content results in cubic-structured ZrAlN while for x > 0.70 the structure is hexagonal. For intermediate Al contents (0.38 < x < 0.70), a  nanocomposite structure with a mixture of cubic, hexagonal and amorphous phases is obtained.

    The cubic ZrAlN phase transforms by nucleation and growth of hexagonal AlN when annealed above 900 C. Annealing of hexagonal ZrAlN thin films (x > 0.70) above 900 C causes formation of AlN and ZrN rich domains within the hexagonal lattice. Annealing of nanocomposite ZrAlN thin films results in formation of cubic ZrN and hexagonal AlN. The transformation is initiated by nucleation and growth of cubic ZrN at temperatures of 1100 C while the AlN-rich domains are still amorphous or nanocrystalline. Growth of hexagonal AlN is suppressed by the high nitrogen content of the films and takes place at annealing temperatures of 1400 C.

    In the more well known TiAlN system, the initial stage of decomposition is spinodal with formation of cubic structured domains enriched in TiN and AlN. By a combination of in-situ xray scattering techniques during annealing and phase field simulations, both the microstructure that evolves during decomposition and the decomposition rate are found to depend on the composition. The results further show that early formation of hexagonal AlN domains during decomposition can cause formation of strains in the cubic TiAlN phase.

    Delarbeid
    1. Age hardening in arc-evaporated ZrAlN thin films
    Åpne denne publikasjonen i ny fane eller vindu >>Age hardening in arc-evaporated ZrAlN thin films
    Vise andre…
    2010 (engelsk)Inngår i: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 62, nr 10, s. 739-741Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Zr0.44Al0.56N1.20 films were deposited by reactive arc evaporation on WC-Co substrates. As-deposited films have a defect-rich NaCl-cubic and wurtzite phase mixture. During annealing at 1100 degrees C the films undergo simultaneous recovery of the ZrN-rich c-ZrAlN nanoscale domains and formation of semicoherent w-ZrAlN nanobricks, while the excess nitrogen is released. This process results in an age hardening effect as high as 36%, as determined by nanoindentation. At 1200 degrees C, the w-AlN recrystallizes and the hardening effect is lost.

    sted, utgiver, år, opplag, sider
    Amsterdam: Elsevier Science B.V., 2010
    Emneord
    PVD, Nanoindentation, TEM, Hardness, Thin films
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-54847 (URN)10.1016/j.scriptamat.2010.01.049 (DOI)000276295800004 ()
    Tilgjengelig fra: 2010-04-16 Laget: 2010-04-16 Sist oppdatert: 2017-12-12bibliografisk kontrollert
    2. Thermal stability and mechanical properties of arc evaporated ZrN/ZrAlN multilayers
    Åpne denne publikasjonen i ny fane eller vindu >>Thermal stability and mechanical properties of arc evaporated ZrN/ZrAlN multilayers
    Vise andre…
    2010 (engelsk)Inngår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 519, nr 2, s. 694-699Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    ZrN1.20/Zr0.44Al0.56N1.20 multilayer films as well as ZrN1.17 and Zr0.44Al0.56N1.20 films were deposited by reactive arc evaporation on WC–Co substrates. Samples were post-deposition annealed for 2 h at 800–1200 °C. As-deposited and heat treated films were characterized by scanning transmission electron microscopy, X-ray diffraction and nanoindentation. The thermal stability was studied using a combination of differential scanning calorimetry, thermogravimetry, and mass spectrometry. The as-deposited Zr0.44Al0.56N1.20 film exhibits a nanocomposite structure of cubic and wurtzite ZrAlN. During annealing, the formation of ZrN- and AlN-rich domains results in age hardening of both the Zr0.44Al0.56N1.20 and the ZrN/ZrAlN multilayers. The age hardening is enhanced in the ZrN/ZrAlN multilayer due to straining of the ZrAlN sublayers in which a maximum hardness of 31 GPa is obtained after annealing at 1100 °C.

    sted, utgiver, år, opplag, sider
    Elsevier, 2010
    Emneord
    Thin films; Zr-Al-N; Multilayer; Arc evaporation; TEM; Hardness
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-62984 (URN)10.1016/j.tsf.2010.08.119 (DOI)000284499500025 ()
    Tilgjengelig fra: 2010-12-08 Laget: 2010-12-08 Sist oppdatert: 2017-12-11
    3. Phase transformations in nanocomposite ZrAlN thin films during annealing
    Åpne denne publikasjonen i ny fane eller vindu >>Phase transformations in nanocomposite ZrAlN thin films during annealing
    Vise andre…
    2012 (engelsk)Inngår i: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 27, nr 13, s. 1716-1724Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Nanocomposite Zr0.52Al0.48N1.11 thin films consisting of crystalline grains surrounded by an amorphous matrix were deposited using cathodic arc evaporation. The structure evolution after annealing of the films was studied using high-energy x-ray scattering and transmission electron microscopy. The mechanical properties were characterized by nanoindentation on as-deposited and annealed films. After annealing in temperatures of 1050-1400 C nucleation and grain growth of cubic ZrN takes place in the film. This increases the hardness, which reaches a maximum while parts of the film remain amorphous. Grain growth of the hexagonal AlN phase occurs above 1400 C.

    sted, utgiver, år, opplag, sider
    Cambridge University Press, 2012
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-75171 (URN)10.1557/jmr.2012.122 (DOI)000307187900007 ()
    Merknad

    funding agencies|Swedish Research Council (VR)||VINNEX center of Excellence on Functional Nanoscale Materials (FunMat)||U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences|DE-AC02-06CH11357|Linnaeus Grants||

    Tilgjengelig fra: 2012-02-20 Laget: 2012-02-20 Sist oppdatert: 2017-12-07bibliografisk kontrollert
    4. Influence of chemical composition and deposition conditions on microstructure evolution during annealing of arc evaporated ZrAlN thin films
    Åpne denne publikasjonen i ny fane eller vindu >>Influence of chemical composition and deposition conditions on microstructure evolution during annealing of arc evaporated ZrAlN thin films
    Vise andre…
    2012 (engelsk)Inngår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 30, nr 3, s. 031504-Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The influence of substrate bias and chemical composition on the microstructure and hardness of arc evaporated Zr1−xAlxN films with 0.12 < x < 0.74 is investigated. A cubic ZrAlN phase is formed at low aluminum contents (x < 0.38) whereas for a high Al-content, above x=0.70, a single-phase hexagonal structure is obtained. For intermediate Al-contents, a two-phase structure is formed. The cubic structured films exhibit higher hardness than the hexagonal structured ones. A low bias results in N-rich films with a partly defect-rich microstructure while a higher substrate bias decreases the grain size and increases the residual stress in the cubic ZrAlN films. Recrystallization and out-diffusion of nitrogen from the lattice in the cubic ZrAlN films takes place during annealing at 800 C, which results in an increased hardness. The cubic ZrAlN phase is stable to annealing temperatures of 1000 C while annealing at higher temperature results in nucleation and growth of hexagonal AlN. In the high Al-content ZrAlN films, formation of ZrN- and AlN-rich domains within the hexagonal lattice during annealing at 1000 C improves the mechanical properties.

    sted, utgiver, år, opplag, sider
    American Vacuum Society, 2012
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-75172 (URN)10.1116/1.3698592 (DOI)000303602800015 ()
    Merknad

    funding agencies|VINN Excellence Center on Functional Nanoscale Materials (FunMat)||

    Tilgjengelig fra: 2012-02-20 Laget: 2012-02-20 Sist oppdatert: 2018-01-03bibliografisk kontrollert
    5. Auto-organizing ZrAlN/ZrAlTiN/TiN multilayers
    Åpne denne publikasjonen i ny fane eller vindu >>Auto-organizing ZrAlN/ZrAlTiN/TiN multilayers
    2012 (engelsk)Inngår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 520, nr 21, s. 6451-6454Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The structural evolution during annealing of arc evaporated ZrAlN/ZrN andZrAlN/TiN multilayers is studied. On annealing, ZrN- and AlN-rich domains form within the ZrAlN sublayers. In the ZrAlN/TiN film, interdiffusion at the ZrAlN/TiN interfaces cause formation of a new cubic Zr(Al,Ti)N phase when annealed at temperatures above 900 C. The formation of this metastable phase results in a substantial increase in hardness of the film, which is retained to annealing temperatures of 1100 C. In the ZrAlN/ZrN film no secondary phases are formed and for annealing at temperatures above 800 C grain growth of the ZrN grains results in decreased hardness.

    sted, utgiver, år, opplag, sider
    Elsevier, 2012
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-75173 (URN)10.1016/j.tsf.2012.06.052 (DOI)000307286100001 ()
    Merknad

    funding agencies|VINN Excellence Center on Functional Nanoscale Materials (FunMat)||

    Tilgjengelig fra: 2012-02-20 Laget: 2012-02-20 Sist oppdatert: 2017-12-07bibliografisk kontrollert
    6. Strain evolution during spinodal decomposition of TiAlN thin films
    Åpne denne publikasjonen i ny fane eller vindu >>Strain evolution during spinodal decomposition of TiAlN thin films
    Vise andre…
    2012 (engelsk)Inngår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 520, nr 17, s. 5542-5549Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    We use a combination of in-situ x-ray scattering experiments during annealing and phase-field simulations to study the strain and microstructure evolution during decomposition of TiAlN thin films. The evolved microstructure is observed to depend on composition, where the larger elastic anisotropy of higher Al content films causes formation of elongated AlN and TiN domains. The simulations show strain formation in the evolving cubic-AlN and TiN domains, which is a combined effect of increasing lattice mismatch and elastic incompatibility between the domains. The experimental results show an increased compressive strain in the TiAlN phase during decomposition due to the onset of transformation to hexagonal-AlN.

    sted, utgiver, år, opplag, sider
    Elsevier, 2012
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-75174 (URN)10.1016/j.tsf.2012.04.059 (DOI)000305770200010 ()
    Tilgjengelig fra: 2012-02-20 Laget: 2012-02-20 Sist oppdatert: 2017-12-07bibliografisk kontrollert
    7. Microstructure evolution during annealing of TiAlN-coatings: A combined in-situ SAXS and phase field study
    Åpne denne publikasjonen i ny fane eller vindu >>Microstructure evolution during annealing of TiAlN-coatings: A combined in-situ SAXS and phase field study
    Vise andre…
    2011 (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    This paper describes in detail the microstructure evolution of Ti0.33Al0.67N and Ti0.50Al0.50N coatings during isothermal annealing studied by in-situ small angle x-ray scattering (SAXS) in combination with phase field simulations. We show that the decomposition occurs in two stages consistent with spinodal decomposition. During the initial stage, the phase segregation proceeds with a constant size of AlN- and TiN-rich domains with a radius of ~0.7 nm for 5 and 20 min at 900 and 850 C respectively in the Ti0.50Al0.50N alloy. The length of the initial stage depends on the temperature as well as the composition, and is shorter for the higher Al content coating. Following the initial stage, the AlN- and TiN-rich domains coarsen. The decomposition process is discussed in terms of Gibbs free energy, diffusion, and gradient energies. Scanning transmission electron microscopy and energy dispersive x-ray spectroscopy of the post annealed coatings confirm a decomposed microstructure with coherent domains rich in AlN and TiN of the same size as determined by SAXS.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-75175 (URN)
    Tilgjengelig fra: 2012-02-20 Laget: 2012-02-20 Sist oppdatert: 2013-10-02bibliografisk kontrollert
  • 131.
    Rogström, Lina
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Ahlgren, Mats
    Sandvik Tooling AB, 126 80 Stockholm, Sweden.
    Almer, J.
    Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439 USA.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Phase transformations in nanocomposite ZrAlN thin films during annealing2012Inngår i: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 27, nr 13, s. 1716-1724Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanocomposite Zr0.52Al0.48N1.11 thin films consisting of crystalline grains surrounded by an amorphous matrix were deposited using cathodic arc evaporation. The structure evolution after annealing of the films was studied using high-energy x-ray scattering and transmission electron microscopy. The mechanical properties were characterized by nanoindentation on as-deposited and annealed films. After annealing in temperatures of 1050-1400 C nucleation and grain growth of cubic ZrN takes place in the film. This increases the hardness, which reaches a maximum while parts of the film remain amorphous. Grain growth of the hexagonal AlN phase occurs above 1400 C.

  • 132.
    Rogström, Lina
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Ghafoor, Naureen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Ahlgren, Mats
    Sandvik Tooling AB, 126 80 Stockholm, Sweden.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Auto-organizing ZrAlN/ZrAlTiN/TiN multilayers2012Inngår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 520, nr 21, s. 6451-6454Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The structural evolution during annealing of arc evaporated ZrAlN/ZrN andZrAlN/TiN multilayers is studied. On annealing, ZrN- and AlN-rich domains form within the ZrAlN sublayers. In the ZrAlN/TiN film, interdiffusion at the ZrAlN/TiN interfaces cause formation of a new cubic Zr(Al,Ti)N phase when annealed at temperatures above 900 C. The formation of this metastable phase results in a substantial increase in hardness of the film, which is retained to annealing temperatures of 1100 C. In the ZrAlN/ZrN film no secondary phases are formed and for annealing at temperatures above 800 C grain growth of the ZrN grains results in decreased hardness.

  • 133.
    Rogström, Lina
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Ghafoor, Naureen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Schroeder, Jeremy
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Schell, N.
    Helmholtz Zentrum Geesthacht, Germany.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Ahlgren, M.
    Sandvik Coromant, Sweden.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Thermal stability of wurtzite Zr1-xAlxN coatings studied by in situ high-energy x-ray diffraction during annealing2015Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 118, nr 3, artikkel-id 035309Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We study the thermal stability of wurtzite (w) structure ZrAlN coatings by a combination of in situ high-energy x-ray scattering techniques during annealing and electron microscopy. Wurtzite structure Zr1-xAlxN coatings with Al-contents from x = 0.46 to x = 0.71 were grown by cathodic arc evaporation. The stability of the w-ZrAlN phase depends on chemical composition where the higher Al-content coatings are more stable. The wurtzite ZrAlN phase was found to phase separate through spinodal decomposition, resulting in nanoscale compositional modulations, i.e., alternating Al-rich ZrAlN layers and Zr-rich ZrAlN layers, forming within the hexagonal lattice. The period of the compositional modulations varies between 1.7 and 2.5 nm and depends on the chemical composition of the coating where smaller periods form in the more unstable, high Zr-content coatings. In addition, Zr leaves the w-ZrAlN lattice to form cubic ZrN precipitates in the column boundaries. (C) 2015 AIP Publishing LLC.

  • 134.
    Rogström, Lina
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Johansson, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan. Seco Tools AB, 737 82 Fagersta, Sweden.
    Ghafoor, Naureen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Influence of chemical composition and deposition conditions on microstructure evolution during annealing of arc evaporated ZrAlN thin films2012Inngår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 30, nr 3, s. 031504-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The influence of substrate bias and chemical composition on the microstructure and hardness of arc evaporated Zr1−xAlxN films with 0.12 < x < 0.74 is investigated. A cubic ZrAlN phase is formed at low aluminum contents (x < 0.38) whereas for a high Al-content, above x=0.70, a single-phase hexagonal structure is obtained. For intermediate Al-contents, a two-phase structure is formed. The cubic structured films exhibit higher hardness than the hexagonal structured ones. A low bias results in N-rich films with a partly defect-rich microstructure while a higher substrate bias decreases the grain size and increases the residual stress in the cubic ZrAlN films. Recrystallization and out-diffusion of nitrogen from the lattice in the cubic ZrAlN films takes place during annealing at 800 C, which results in an increased hardness. The cubic ZrAlN phase is stable to annealing temperatures of 1000 C while annealing at higher temperature results in nucleation and growth of hexagonal AlN. In the high Al-content ZrAlN films, formation of ZrN- and AlN-rich domains within the hexagonal lattice during annealing at 1000 C improves the mechanical properties.

  • 135.
    Rogström, Lina
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Johansson, Mats P.
    Seco Tools AB, Sweden.
    Pilemalm, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Ghafoor, Naureen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Johnson, L. J. S.
    Sandvik Coromant, Sweden.
    Schell, N.
    Helmholtz Zentrum Geesthacht, Germany.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Decomposition routes and strain evolution in arc deposited TiZrAlN coatings2019Inngår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 779, s. 261-269Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Phase, microstructure, and strain evolution during annealing of arc deposited TiZrAlN coatings are studied using in situ x-ray scattering and ex situ transmission electron microscopy. We find that the decomposition route changes from nucleation and growth of wurtzite AlN to spinodal decomposition when the Zr-content is decreased and the Al-content increases. Decomposition of Ti0.31Zr0.24Al0.45N results in homogeneously distributed wurtzite AlN grains in a cubic, dislocation-dense matrix of TiZrN consisting of domains of different chemical composition. The combination of high dislocation density, variation of chemical composition within the cubic grains, and evenly distributed wurtzite AlN grains results in high compressive strains, -1.1%, which are retained after 3 h at 1100 degrees C. In coatings with higher Zr-content, the strains relax during annealing above 900 degrees C due to grain growth and defect annihilation. (C) 2018 Elsevier B.V. All rights reserved.

    Fulltekst tilgjengelig fra 2020-11-14 12:11
  • 136.
    Rogström, Lina
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Johansson-Jöesaar, Mats P.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. SECO Tools AB, Sweden.
    Landälv, Ludvig
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten. Sandvik Coromant, Sweden.
    Ahlgren, M.
    Sandvik Coromant, Sweden.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Wear behavior of ZrAlN coated cutting tools during turning2015Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 282, s. 180-187Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study we explore the cutting performance of ZrAlN coatings. WC:Co cutting inserts coated by cathodic arc evaporated Zr1-xAlxN coatings with x between 0 and 0.83 were testeciin a longitudinal turning operation. The progress of wear was studied by optical microscopy and the used inserts were studied by electron microscopy. The cutting performance was correlated to the coating composition and the best performance was found for the coating with highest Al-content consisting of a wurtzite ZrAlN phase which is assigned to its high thermal stability. Material from the work piece was observed to adhere to the inserts during turning and the amount of adhered material and its chemical composition is independent on the Al-content of the coating. (C) 2015 Elsevier B.V. All rights reserved.

  • 137.
    Rogström, Lina
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Johnson, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Johansson, Mats
    SECO Tools AB, Fagersta.
    Ahlgren, Mats
    Sandvik Tooling AB, Stockholm.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Thermal stability and mechanical properties of arc evaporated ZrN/ZrAlN multilayers2010Inngår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 519, nr 2, s. 694-699Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    ZrN1.20/Zr0.44Al0.56N1.20 multilayer films as well as ZrN1.17 and Zr0.44Al0.56N1.20 films were deposited by reactive arc evaporation on WC–Co substrates. Samples were post-deposition annealed for 2 h at 800–1200 °C. As-deposited and heat treated films were characterized by scanning transmission electron microscopy, X-ray diffraction and nanoindentation. The thermal stability was studied using a combination of differential scanning calorimetry, thermogravimetry, and mass spectrometry. The as-deposited Zr0.44Al0.56N1.20 film exhibits a nanocomposite structure of cubic and wurtzite ZrAlN. During annealing, the formation of ZrN- and AlN-rich domains results in age hardening of both the Zr0.44Al0.56N1.20 and the ZrN/ZrAlN multilayers. The age hardening is enhanced in the ZrN/ZrAlN multilayer due to straining of the ZrAlN sublayers in which a maximum hardness of 31 GPa is obtained after annealing at 1100 °C.

  • 138.
    Rogström, Lina
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Johnson, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Johansson, Mats P.
    SECO Tools AB, Fagersta, Sweden.
    Ahlgren, Mats
    Sandvik Tooling AB.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Age hardening in arc-evaporated ZrAlN thin films2010Inngår i: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 62, nr 10, s. 739-741Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Zr0.44Al0.56N1.20 films were deposited by reactive arc evaporation on WC-Co substrates. As-deposited films have a defect-rich NaCl-cubic and wurtzite phase mixture. During annealing at 1100 degrees C the films undergo simultaneous recovery of the ZrN-rich c-ZrAlN nanoscale domains and formation of semicoherent w-ZrAlN nanobricks, while the excess nitrogen is released. This process results in an age hardening effect as high as 36%, as determined by nanoindentation. At 1200 degrees C, the w-AlN recrystallizes and the hardening effect is lost.

  • 139.
    Rogström, Lina
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Ullbrand, Jennifer
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Almer, J.
    Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 USA.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Jansson, B.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan. Seco Tools AB, 737 82 Fagersta, Sweden.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Strain evolution during spinodal decomposition of TiAlN thin films2012Inngår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 520, nr 17, s. 5542-5549Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We use a combination of in-situ x-ray scattering experiments during annealing and phase-field simulations to study the strain and microstructure evolution during decomposition of TiAlN thin films. The evolved microstructure is observed to depend on composition, where the larger elastic anisotropy of higher Al content films causes formation of elongated AlN and TiN domains. The simulations show strain formation in the evolving cubic-AlN and TiN domains, which is a combined effect of increasing lattice mismatch and elastic incompatibility between the domains. The experimental results show an increased compressive strain in the TiAlN phase during decomposition due to the onset of transformation to hexagonal-AlN.

  • 140.
    Saleem, Hassan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Thermal Stability of cubic and nanocrystalline arcevaporated TiCrAlN coatings2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    (TixCryAlz)N coatings were deposited on WC-Co substrate using cathodic arc evaporation technique to investigate phase transformation, thermal stability, and high temperature mechanical properties. Two compositions Ti0.34Cr0.33Al0.33N and Ti0.24Cr0.02Al0.74N were studied and compared with industrial standard hard TiAlN coating. These compositions were annealed at 800 oC up to 1100 oC. X-ray diffractogram showed a mixture of cubical and hexagonal phases in as-deposited state for high Al content composition. Differential scanning calorimetry showed that spinodal decomposition starts late compared to TiAlN coating. The results from nanoindentation did not show age hardening in Ti0.34Cr0.33Al0.33N composition while composition Ti0.24Cr0.02Al0.74N showed a significant increase in hardness compared with TiAlN coating. Also the Ti0.24Cr0.02Al0.74N retains its hardness over a wide temperature range while TiAlN coating hardness decreases after annealing at 900 oC. Upon annealing at 1400 oC, the coating decomposes into equilibrium phases i.e., c-TiN and h-AlN while Cr found to be in oxides form. HRTEM results revealed that the coating consists of nanocrystalline grains with defects rich regions.

  • 141.
    Scholle, A
    et al.
    University of Paderborn.
    Greulich-Weber, S
    University of Paderborn.
    As, D J
    University of Paderborn.
    Mietze, Ch
    University of Paderborn.
    Nguyen, Tien Son
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hemmingsson, Carl
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Monemar, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Gerstmann, U
    University of Paderborn.
    Sanna, S
    University of Paderborn.
    Rauls, E
    University of Paderborn.
    Schmidt, W G
    University of Paderborn.
    Magnetic characterization of conductance electrons in GaN2010Inngår i: Physica Status Solidi, Vol. 247, John Wiley and Sons, Ltd , 2010, Vol. 247, nr 7, s. 1728-1731Konferansepaper (Fagfellevurdert)
    Abstract [en]

    New electron paramagnetic resonance (EPR) measurements in hexagonal and cubic GaN intentionally doped with silicon are presented. In both type of samples the well-known EPR resonance of the dominant shallow donor is observed, whereby the g-tensors are determined to g(parallel to) = 1.9512, g(perpendicular to) = 1.9485 (free-standing hexagonal GaN) and g = 1.9533 (cubic GaN layer grown on 3C-SiC substrate). The spectra show an exceptionally small line width below 0.4 mT and contain no further signature. As a result, beside the line width itself, the EPR line is characterized by its g-tensor exclusively. With the help of a qualitative analysis of the Si donor wave function within effective mass theory (EMT) and a followed up calculation of the hyperfine (HF) splittings in the framework of density functional theory (DFT) the characteristic shape of the EPR lines can be explained by an enhanced delocalization of the unpaired electrons of shallow Si donors at the gallium sublattice due to overlapping impurity and conduction bands.

  • 142.
    Schramm Benítez, Isabella Citlalli
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Defect-engineered (Ti,Al)N thin films2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis investigates the effect of point defects (nitrogen vacancies and interstitials) and multilayering ((Ti,Al)N/TiN) on the phase transformations in cathodic arc-evaporated cubic (Ti,Al)N thin films at elevated temperatures. Special attention is paid to the evolution of the beneficial spinodal decomposition into c-TiN and c-AlN, the detrimental formation of wurtzite AlN and the potential application as hard coating in cutting tools.

    c-(Ti1-xAlx)Ny thin films with varying Al fractions and N content (y = 0.93 to 0.75) show a delay in the spinodal decomposition when increasing the amount of N vacancies. This results in a 300 °C upshift in the age hardening and a delay in the w-AlN formation, while additions of self-interstitials enhance phase separation. High temperature interaction between hard metal substrates and thin films is more pronounced when increasing N deficiency through diffusion of substrate elements into the film. Low N content films (y = 0.58 to 0.40) showed formation of additional phases such as Ti4AlN3, Ti2AlN, Al5Ti2 and Al3Ti during annealing and a transformation from Ti2AlN to Ti4AlN3 via intercalation. The multilayer structure of TiN/TiAlN results in surfacedirected spinodal decomposition that affects the decomposition behavior. Careful use of these effects appears as a promising method to improve cutting tool performance.

    Delarbeid
    1. Impact of nitrogen vacancies on the high temperature behavior of (Ti1-xAlx)N-y alloys
    Åpne denne publikasjonen i ny fane eller vindu >>Impact of nitrogen vacancies on the high temperature behavior of (Ti1-xAlx)N-y alloys
    Vise andre…
    2016 (engelsk)Inngår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 119, s. 218-228Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Substoichiometric solid solution alloys of cubic (Ti1-xAlx)N-y with x = 0.26, 0.48 and 0.60, and y ranging from 0.93 to 0.75 were grown by cathodic arc deposition. The influence of nitrogen deficiency on their thermal stability was studied by X-ray diffractometry, differential scanning calorimetry, scanning electron microscopy, and atom probe tomography. The nitrogen deficiency did not significantly affect the columnar growth nor the as deposited hardness. At elevated temperatures, alloys with x = 0.48 and 0.60 decompose isostructurally into cubic c-TiN and cubic c-AlN domains, which is consistent with spinodal decomposition. The decomposition is retarded by decreasing the nitrogen content, e.g. the formed isostructural domains in (Ti0.52Al0.48)N-0.92 at 900 degrees C are similar in size to (Ti0.52Al0.48)N-0.75 at 1200 degrees C. The formation of hexagonal w-AlN is shifted to higher temperatures by decreasing nitrogen content. Nucleation and growth of Al-Ti clusters in a Ti rich matrix were observed for the alloys with high Ti content, x = 0.26. These results suggest that nitrogen deficiency reduces the driving force for phase separation. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

    sted, utgiver, år, opplag, sider
    PERGAMON-ELSEVIER SCIENCE LTD, 2016
    Emneord
    TiAlN system; Nitrogen vacancies; Spinodal decomposition; Atom probe tomography; Thin films
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-132334 (URN)10.1016/j.actamat.2016.08.024 (DOI)000384778300021 ()
    Merknad

    Funding Agencies|Erasmus Mundus doctoral program DocMASE; Swedish Research Council VR [621-2012-4401]; Swedish Foundation for Strategic Research, SSF via MultiFilms program [RMA08-0069]; Swedish government strategic research area grant AFM - SFO MatLiU [2009-00971]; VIN-NOVA (M - Era.net) [2013-02355(MC2)]; DFG; federal state government of Saarland [INST 256/298-1 FUGG]; AME-Lab (European Regional Development Fund) [C/4-EFRE-13/2009/Br]

    Tilgjengelig fra: 2016-11-12 Laget: 2016-11-01 Sist oppdatert: 2018-01-03
    2. Solid state formation of Ti4AlN3 in cathodic arc deposited (Ti1-xAlx)N-y alloys
    Åpne denne publikasjonen i ny fane eller vindu >>Solid state formation of Ti4AlN3 in cathodic arc deposited (Ti1-xAlx)N-y alloys
    Vise andre…
    2017 (engelsk)Inngår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 129, s. 268-277Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Reactive cathodic arc deposition was used to grow substoichiometric solid solution cubic c-(Ti1-xAlx)N-y thin films. The films were removed from the substrate and then heated in an argon environment to 1400 degrees C. Via solid state reactions, formation of MAX phase Ti4AlN3 was obtained. Additional phases such as Ti2AlN, c-TiN, w-AIN, Al5Ti2 and Al3Ti were also present during the solid state reaction. Ti4AlN3 formation was observed in samples with an Al metal fraction x amp;lt; 0.63 and a nitrogen content 0.4 amp;lt; y amp;lt; 0.6. Regardless of the initial composition, formation of Ti4AlN3 started in Ti2AlN crystal plates in the temperature range between 1200 and 1400 degrees C. Accompanying the onset of Ti4AlN3 was the presence of an intermediate structure identified as Ti6Al2N4, consisting of alternating layers of intergrown Ti2AlN and Ti4AlN3 phases with a half-unit-cell stacking. We suggest that the formation of Ti4AlN3 occurred via intercalation of aluminum and nitrogen along the basal plane accompanied by a simultaneous detwinning process. In addition we propose that this formation mechanism can be used to obtain MAX phases of high n order. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

    sted, utgiver, år, opplag, sider
    PERGAMON-ELSEVIER SCIENCE LTD, 2017
    Emneord
    MAX phase; Intergrown phase; Thin films; Solid state reaction; Intercalation
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-137593 (URN)10.1016/j.actamat.2017.03.001 (DOI)000400033900026 ()
    Merknad

    Funding Agencies|European Unions Erasmus Mundus doctoral program DocMASE; Swedish Research Council [621-2012-4401]; Swedish government strategic research area grant AFM SFO MatLiU [2009-00971]; VINNOVA (M - Era.net project MC2) [2013-02355]; European Research Council under the European Communitys Seventh Framework Program (FP) [335383]; DFG; federal state government of Saarland [INST 256/298-1 FUGG, INST 256/431-1 FUGG]; European Regional Development Fund [AME-Lab C/4-EFRE-13/2009/Br]

    Tilgjengelig fra: 2017-05-22 Laget: 2017-05-22 Sist oppdatert: 2018-03-19
    3. Effects of nitrogen vacancies on phase stability and mechanical properties of arc deposited (Ti0.52Al0.48)Ny (y<1) coatings
    Åpne denne publikasjonen i ny fane eller vindu >>Effects of nitrogen vacancies on phase stability and mechanical properties of arc deposited (Ti0.52Al0.48)Ny (y<1) coatings
    Vise andre…
    2017 (engelsk)Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 330, nr Supplement C, s. 77-86Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Nitrogen sub-stoichiometric (Ti0.52Al0.48)Ny (0.92 ≥ y  ≥ 0.46) coatings were grown in a mixed Ar/N2 atmosphere by cathodic arc deposition on cemented carbide (WC/Co-based) substrates. The coatings present a columnar structure with decreasing column widths from 250 to 60nm, due to a corresponding reduced N content, accompanied by changes in preferred orientation from 200 to 111 to 220. Among these, coatings prepared with 0.92≥y≥0.75 exhibit spinodal decomposition and consequently age hardening at elevated temperatures. A reduced N content upshifts the hardness maximum by >300 °C. For these samples, the high temperature treatment resulted in interdiffusion of substrate elements, Co and C, mainly along column boundaries. Nevertheless, no detrimental effect in the hardness could be correlated. Conversely, a low N content sample (y=0.46) presents significant lattice diffusion of substrate elements Co, C, W, and Ta in the coating. In this case, the substrate elements are present throughout the coating, forming additional phases such as c-Ti(C,N), c-Co(Al,Ti,W), and c-(Ti,W,Ta)(C,N), with an observed increased hardness from 16 to 25GPa. We suggest that the substitution of nitrogen by carbon and the solution of W and Ta in c-TiN are responsible for the observed hardening. Our investigation shows the potential of sub-stoichiometric (Ti1-xAlx)Ny coatings for high temperature applications such as cutting tools and puts forth corresponding criteria for N content selection.

    sted, utgiver, år, opplag, sider
    Elsevier, 2017
    Emneord
    TiAlN, Thin films, Nitrogen vacancies, Spinodal decomposition, Age hardening
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-142115 (URN)10.1016/j.surfcoat.2017.09.043 (DOI)000414819700010 ()2-s2.0-85030314026 (Scopus ID)
    Merknad

    Funding agencies: European Unions Erasmus Mundus doctoral program DocMASE; Swedish Research Council [621-2012-4401]; Swedish Government Strategic Research Area grant AFM - SFO MatLiU [2009-00971]; VINNOVA (M - Era.net project MC2 grant) [2013-02355]; DFG [INST 256/298-1 FU

    Tilgjengelig fra: 2017-10-23 Laget: 2017-10-23 Sist oppdatert: 2018-01-03bibliografisk kontrollert
    4. Enhanced thermal stability and mechanical properties of nitrogen deficient titanium aluminum nitride (Ti0.54Al0.46Ny) thin films by tuning the applied negative bias voltage
    Åpne denne publikasjonen i ny fane eller vindu >>Enhanced thermal stability and mechanical properties of nitrogen deficient titanium aluminum nitride (Ti0.54Al0.46Ny) thin films by tuning the applied negative bias voltage
    Vise andre…
    2017 (engelsk)Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 122, nr 6, artikkel-id 065301Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Aspects on the phase stability and mechanical properties of nitrogen deficient (Ti0.54Al0.46)N-y alloys were investigated. Solid solution alloys of (Ti,Al)N were grown by cathodic arc deposition. The kinetic energy of the impinging ions was altered by varying the substrate bias voltage from -30V to -80 V. Films deposited with a high bias value of -80V showed larger lattice parameter, finer columnar structure, and higher compressive residual stress resulting in higher hardness than films biased at -30V when comparing their as-deposited states. At elevated temperatures, the presence of nitrogen vacancies and point defects (anti-sites and self-interstitials generated by the ion-bombardment during coating deposition) in (Ti0.54Al0.46)N-0.87 influence the driving force for phase separation. Highly biased nitrogen deficient films have point defects with higher stability during annealing, which cause a delay of the release of the stored lattice strain energy and then accelerates the decomposition tendencies to thermodynamically stable c-TiN and w-AlN. Low biased nitrogen deficient films have retarded phase transformation to w-AlN, which results in the prolongment of age hardening effect up to 1100 degrees C, i.e., the highest reported temperature for Ti-Al-N material system. Our study points out the role of vacancies and point defects in engineering thin films with enhanced thermal stability and mechanical properties for high temperature hard coating applications. Published by AIP Publishing.

    sted, utgiver, år, opplag, sider
    American Institute of Physics (AIP), 2017
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-140514 (URN)10.1063/1.4986350 (DOI)000407742400032 ()
    Merknad

    Funding Agencies|European Unions Erasmus Mundus doctoral program in Materials Science and Engineering (DocMASE); Swedish Research Council [621-2012-4401]; Swedish government strategic research area grant AFM - SFO MatLiU [2009-00971]; VINNOVA [2013-02355]; DFG; federal state government of Saarland [INST 256/298-1 FUGG]; European Regional Development Fund [AME-Lab C/4-EFRE-13/2009/Br]

    Tilgjengelig fra: 2017-09-11 Laget: 2017-09-11 Sist oppdatert: 2019-05-27
    5. Surface directed spinodal decomposition at TiAlN / TiN interfaces
    Åpne denne publikasjonen i ny fane eller vindu >>Surface directed spinodal decomposition at TiAlN / TiN interfaces
    Vise andre…
    2013 (engelsk)Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, nr 11, s. 114305-1-114305-8Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In contrast to the monolithic c-Ti1-xAlxN, the isostructural spinodal decomposition to c-AlN and c-TiN of the c-Ti1-xAlxN/TiN multilayers have the same onset temperature regardless of composition (x=0.50 and 0.66). The onset is also located at a lower temperature compared to the monoliths with the same Al-content, revealed by differential scanning calorimetry. Zcontrast STEM imaging shows a decomposed structure of the multilayers at a temperature where it is not present in the monoliths. Atom probe tomography reveal the formation of an AlN-rich layer followed by a TiN-rich area parallel to the interface in the decomposed Ti0.34Al0.66N/TiN coating, consistent with surface directed spinodal decomposition. Phase field simulations predict such behavior and show that the surface directed spinodal decomposition is affected by in the internal interfaces, as deposited elemental fluctuations, coherency stresses and alloy composition.

    sted, utgiver, år, opplag, sider
    American Institute of Physics (AIP), 2013
    Emneord
    Surface directed spinodal decomposition, Titanium aluminium nitride, Phase field simulations, Atom probe tomography
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-84704 (URN)10.1063/1.4795155 (DOI)000316545200054 ()
    Merknad

    Funding Agencies|Swedish Foundation for Strategic Research (SSF) project Designed Multicomponent Coatings (MultiFilms)||Swedish Research Council (VR)||Erasmus Mundus doctoral program DocMASE||EU|C/4-EFRE-13/2009/Br|DFG||federal state government of Saarland|INST 256/298-1 FUGG|

    Tilgjengelig fra: 2012-10-17 Laget: 2012-10-17 Sist oppdatert: 2018-02-23bibliografisk kontrollert
  • 143.
    Schramm, Isabella C.
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Pauly, C.
    Functional Materials, Department Materials Science, Saarland University, Saarbrucken, Germany.
    Johansson Jõesaar, Mats P.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. SECO Tools AB, Fagersta, Sweden.
    Slawik, S.
    Functional Materials, Department Materials Science, Saarland University, Saarbrucken, Germany.
    Suarez, S.
    Functional Materials, Department Materials Science, Saarland University, Saarbrucken, Germany.
    Mücklich, F.
    Functional Materials, Department Materials Science, Saarland University, Saarbrucken, Germany.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Effects of nitrogen vacancies on phase stability and mechanical properties of arc deposited (Ti0.52Al0.48)Ny (y<1) coatings2017Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 330, nr Supplement C, s. 77-86Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nitrogen sub-stoichiometric (Ti0.52Al0.48)Ny (0.92 ≥ y  ≥ 0.46) coatings were grown in a mixed Ar/N2 atmosphere by cathodic arc deposition on cemented carbide (WC/Co-based) substrates. The coatings present a columnar structure with decreasing column widths from 250 to 60nm, due to a corresponding reduced N content, accompanied by changes in preferred orientation from 200 to 111 to 220. Among these, coatings prepared with 0.92≥y≥0.75 exhibit spinodal decomposition and consequently age hardening at elevated temperatures. A reduced N content upshifts the hardness maximum by >300 °C. For these samples, the high temperature treatment resulted in interdiffusion of substrate elements, Co and C, mainly along column boundaries. Nevertheless, no detrimental effect in the hardness could be correlated. Conversely, a low N content sample (y=0.46) presents significant lattice diffusion of substrate elements Co, C, W, and Ta in the coating. In this case, the substrate elements are present throughout the coating, forming additional phases such as c-Ti(C,N), c-Co(Al,Ti,W), and c-(Ti,W,Ta)(C,N), with an observed increased hardness from 16 to 25GPa. We suggest that the substitution of nitrogen by carbon and the solution of W and Ta in c-TiN are responsible for the observed hardening. Our investigation shows the potential of sub-stoichiometric (Ti1-xAlx)Ny coatings for high temperature applications such as cutting tools and puts forth corresponding criteria for N content selection.

  • 144.
    Schramm, Isabella
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten. University of Saarland, Germany.
    Johansson Jöesaar, Mats P.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. SECO Tools AB, Sweden.
    Jensen, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Muecklich, F.
    University of Saarland, Germany.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Impact of nitrogen vacancies on the high temperature behavior of (Ti1-xAlx)N-y alloys2016Inngår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 119, s. 218-228Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Substoichiometric solid solution alloys of cubic (Ti1-xAlx)N-y with x = 0.26, 0.48 and 0.60, and y ranging from 0.93 to 0.75 were grown by cathodic arc deposition. The influence of nitrogen deficiency on their thermal stability was studied by X-ray diffractometry, differential scanning calorimetry, scanning electron microscopy, and atom probe tomography. The nitrogen deficiency did not significantly affect the columnar growth nor the as deposited hardness. At elevated temperatures, alloys with x = 0.48 and 0.60 decompose isostructurally into cubic c-TiN and cubic c-AlN domains, which is consistent with spinodal decomposition. The decomposition is retarded by decreasing the nitrogen content, e.g. the formed isostructural domains in (Ti0.52Al0.48)N-0.92 at 900 degrees C are similar in size to (Ti0.52Al0.48)N-0.75 at 1200 degrees C. The formation of hexagonal w-AlN is shifted to higher temperatures by decreasing nitrogen content. Nucleation and growth of Al-Ti clusters in a Ti rich matrix were observed for the alloys with high Ti content, x = 0.26. These results suggest that nitrogen deficiency reduces the driving force for phase separation. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  • 145.
    Schramm, Isabella
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Saarland University, Germany.
    Pauly, C.
    Saarland University, Germany.
    Johansson Jöesaar, Mats P
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. SECO Tools AB, Sweden.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Schmauch, J.
    Saarland University, Germany.
    Muecklich, F.
    Saarland University, Germany.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Solid state formation of Ti4AlN3 in cathodic arc deposited (Ti1-xAlx)N-y alloys2017Inngår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 129, s. 268-277Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reactive cathodic arc deposition was used to grow substoichiometric solid solution cubic c-(Ti1-xAlx)N-y thin films. The films were removed from the substrate and then heated in an argon environment to 1400 degrees C. Via solid state reactions, formation of MAX phase Ti4AlN3 was obtained. Additional phases such as Ti2AlN, c-TiN, w-AIN, Al5Ti2 and Al3Ti were also present during the solid state reaction. Ti4AlN3 formation was observed in samples with an Al metal fraction x amp;lt; 0.63 and a nitrogen content 0.4 amp;lt; y amp;lt; 0.6. Regardless of the initial composition, formation of Ti4AlN3 started in Ti2AlN crystal plates in the temperature range between 1200 and 1400 degrees C. Accompanying the onset of Ti4AlN3 was the presence of an intermediate structure identified as Ti6Al2N4, consisting of alternating layers of intergrown Ti2AlN and Ti4AlN3 phases with a half-unit-cell stacking. We suggest that the formation of Ti4AlN3 occurred via intercalation of aluminum and nitrogen along the basal plane accompanied by a simultaneous detwinning process. In addition we propose that this formation mechanism can be used to obtain MAX phases of high n order. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  • 146.
    Schroeder, Jeremy
    et al.
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Thomson, W.
    PVD Prod Inc, MA 01887 USA.
    Howard, B.
    PVD Prod Inc, MA 01887 USA.
    Schell, N.
    Helmholtz Zentrum Geesthacht, Germany.
    Näslund, Lars-Åke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Rogström, Lina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Johansson-Jöesaar, Mats P.
    Seco Tools AB, Sweden.
    Ghafoor, Naureen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Nothnagel, E.
    PVD Prod Inc, MA 01887 USA.
    Shepard, A.
    PVD Prod Inc, MA 01887 USA.
    Greer, J.
    PVD Prod Inc, MA 01887 USA.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Industry-relevant magnetron sputtering and cathodic arc ultra-high vacuum deposition system for in situ x-ray diffraction studies of thin film growth using high energy synchrotron radiation2015Inngår i: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 86, nr 9, s. 095113-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present an industry-relevant, large-scale, ultra-high vacuum (UHV) magnetron sputtering and cathodic arc deposition system purposefully designed for time-resolved in situ thin film deposition/annealing studies using high-energy (greater than50 keV), high photon flux (greater than10(12) ph/s) synchrotron radiation. The high photon flux, combined with a fast-acquisition-time (less than1 s) two-dimensional (2D) detector, permits time-resolved in situ structural analysis of thin film formation processes. The high-energy synchrotron-radiation based x-rays result in small scattering angles (less than11 degrees), allowing large areas of reciprocal space to be imaged with a 2D detector. The system has been designed for use on the 1-tonne, ultra-high load, high-resolution hexapod at the P07 High Energy Materials Science beamline at PETRA III at the Deutsches Elektronen-Synchrotron in Hamburg, Germany. The deposition system includes standard features of a typical UHV deposition system plus a range of special features suited for synchrotron radiation studies and industry-relevant processes. We openly encourage the materials research community to contact us for collaborative opportunities using this unique and versatile scientific instrument. (C) 2015 AIP Publishing LLC.

  • 147.
    Selegård, Linnéa
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Ahrén, Maria
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Brommesson, Caroline
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska högskolan.
    Söderlind, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Persson, Per. O. Å
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Uvdal, Kajsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Bifunctional gadolinium decorated ZnO nanocrystals integrating both enhanced MR signal and bright fluorescence2013Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Gadolinium decorated ZnO nanoparticles simultaneously possess both fluorescent and MR enhancement properties. These ZnO nanoparticles are crystalline and shielded by an amorphous gadolinium acetate matrix. Interestingly, the Gd-acetate decoration enhances the fluorescence emission of the ZnO nanoparticles. The quantum yield does increase for samples with high Gd/Zn relative ratios and these samples do also show a higher colloidal stability.

    In addition, these nanoparticles show an enhanced relaxivity value per Gd atom (r119.9mM1s-1) compared to results earlier reported both on Gd alloyed ZnO nanoparticles and pure Gd2O3 nanoparticles. This improvement is considered to be due to the close proximity of Gd atoms and surrounding water molecules. A comprehensive study of the quantum yield and the relaxivity, as a function of composition, enable us to identify the ultimate design/composition of gadolinium decorated ZnO nanoparticles for optimum fluorescence and MR enhancement properties.

  • 148.
    Sen Karaman, D.
    et al.
    Abo Akad University, Finland; Abo Akad University, Finland.
    Sarwar, S.
    Bose Institute, India.
    Desai, D.
    Abo Akad University, Finland.
    Björk, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Chakrabarti, P.
    Bose Institute, India.
    Rosenholm, J. M.
    Abo Akad University, Finland.
    Chakraborti, S.
    Bose Institute, India; Indiana University, IN USA.
    Shape engineering boosts antibacterial activity of chitosan coated mesoporous silica nanoparticle doped with silver: a mechanistic investigation2016Inngår i: Journal of materials chemistry. B, ISSN 2050-750X, E-ISSN 2050-7518, Vol. 4, nr 19, s. 3292-3304Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, mesoporous silica nanoparticles (MSPs) of different size and shape were developed, and their surface coatings were utilized to study their differential effects in enhancing antibacterial activity. In brief, MSPs with three different aspect ratios (1, 2 and 4) were prepared, doped with silver ions and finally coated with the polymer chitosan. Both Gram-positive and Gram-negative bacteria were treated with the MSPs. Results indicate that silver ion doped and chitosan coated MSPs with the aspect ratio of 4 (Cht/MSP4:Ag+) have the highest antimicrobial activity among the prepared series. Further studies revealed that Cht/MSP4:Ag+ was most effective against Escherichia coli (E.coli) and least effective against Vibrio cholerae (V. cholerae). To investigate the detailed inhibition mechanism of the MSPs, the interaction of the nanoparticles with E.coli membranes and its intracellular DNA was assessed using various spectroscopic and imaging-based techniques. Furthermore, to increase the efficiency of the MSPs, a combinatorial antibacterial strategy was also explored, where nanoparticles, in combination with kanamycin (antibiotic), were used against Vibrio Cholerae (V. cholerae). Toxicity screening of these on MSPs was conducted on Caco-2 cells, and the results show that the dose used for antibacterial screening is below the limit of the toxicity threshold. Our findings show that both shape and surface engineering contribute positively towards killing bacteria, and the newly developed silver ion-doped and chitosan-coated MSPs have good potential as antimicrobial nanomaterials.

  • 149.
    Sen Karaman, Didem
    et al.
    Abo Akad University, Finland .
    Desai, Diti
    Abo Akad University, Finland Maharaja Sayajirao University of Baroda, India .
    Senthilkumar, Rajendran
    Abo Akad University, Finland .
    Johansson, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Ratts, Natalie
    Abo Akad University, Finland Abo Akad University, Finland Abo Akad University, Finland University of Turku, Finland .
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    E Eriksson, John
    Abo Akad University, Finland .
    Sahlgren, Cecilia
    Abo Akad University, Finland Abo Akad University, Finland University of Turku, Finland .
    Toivola, Diana M.
    Abo Akad University, Finland Turku Centre Disease Modeling, Finland .
    Rosenholm, Jessica M.
    Abo Akad University, Finland .
    Shape engineering vs organic modification of inorganic nanoparticles as a tool for enhancing cellular internalization2012Inngår i: Nanoscale Research Letters, ISSN 1931-7573, E-ISSN 1556-276X, Vol. 7, nr 358Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In nanomedicine, physicochemical properties of the nanocarrier affect the nanoparticles pharmacokinetics and biodistribution, which are also decisive for the passive targeting and nonspecific cellular uptake of nanoparticles. Size and surface charge are, consequently, two main determining factors in nanomedicine applications. Another important parameter which has received much less attention is the morphology (shape) of the nanocarrier. In order to investigate the morphology effect on the extent of cellular internalization, two similarly sized but differently shaped rod-like and spherical mesoporous silica nanoparticles were synthesized, characterized and functionalized to yield different surface charges. The uptake in two different cancer cell lines was investigated as a function of particle shape, coating (organic modification), surface charge and dose. According to the presented results, particle morphology is a decisive property regardless of both the different surface charges and doses tested, whereby rod-like particles internalized more efficiently in both cell lines. At lower doses whereby the shape-induced advantage is less dominant, charge-induced effects can, however, be used to fine-tune the cellular uptake as a prospective secondary uptake regulator for tight dose control in nanoparticle-based drug formulations.

  • 150.
    Senthilkumar, Rajendran
    et al.
    Abo Akad University, Finland.
    Sen Karaman, Didem
    Abo Akad University, Finland.
    Paul, Preethy
    Abo Akad University, Finland.
    Johansson, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Eriksson, John E.
    Abo Akad University, Finland.
    Rosenholm, Jessica M.
    Abo Akad University, Finland.
    Targeted delivery of a novel anticancer compound anisomelic acid using chitosan-coated porous silica nanorods for enhancing the apoptotic effect2015Inngår i: BIOMATERIALS SCIENCE, ISSN 2047-4830, Vol. 3, nr 1, s. 103-111Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Targeted cancer therapies are currently a strong focus in biomedical research. The most common approach is to use nanocarrier-based targeting to specifically deliver conventional anticancer drugs to enhance their therapeutic efficacy, increase bioavailability, and decrease the side-effects on normal cells. A step further towards higher specificity and efficacy would be to employ specific novel drugs along with specific nanocarrier-based targeting. Our recent studies have demonstrated that a plant-derived diterpenoid compound, anisomelic acid (AA), induces apoptosis in cervical cancer cells. In this work, we describe the development of a folic acid (FA)-targeted AA delivery system using chitosan-coated rod-shaped mesoporous silica particles (Chitosan-NR-MSP). The cellular internalization and uptake enhancement of the FA-Chitosan-NR-MSP towards cancerous folate receptor (FR)-positive (SiHa and HeLa) and/or normal FR-negative (HEK 293) cells were assessed, which indicated that the intracellular uptake of FA-conjugated Chitosan-NR-MSP was more target-specific. Furthermore, the induction of apoptosis by AA-loaded chitosan-coated rod-shaped particles on SiHa cells was studied. By employing caspase-3 activation and PARP cleavage as measure of apoptosis, the FA-particle mediated AA treatment was clearly more effective, significantly enhancing apoptosis in comparison to non-targeted Chitosan-NR-MSP or free AA in SiHa cells, suggesting that the FA-Chitosan-NR-MSPs can be potentially utilized as a drug delivery system for cervical cancer treatment.

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