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  • 1.
    Nayak, Sanjay Kumar
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Hsu, Tun-Wei
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Gibmeier, Jens
    Karlsruhe Inst Technol, Germany.
    Schell, Norbert
    Helmholtz Zentrum Hereon, Germany.
    Birch, Jens
    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.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Dynamic evolution of internal stress, grain growth, and crystallographic texture in arc-evaporated AlTiN thin films using in-situ synchrotron x-ray diffraction2024Ingår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 272, artikel-id 119899Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Understanding the nucleation and growth of polycrystalline thin films is a long-standing goal. Numerous studies have been done to determine the grain size, stress, and the ideal crystallographic orientation in films. The majority of past studies have either employed an ex-situ methodology or only monitor the development of macroscopic stress in real-time. There has never been any research done on the simultaneous changes in crystallographic texture, grain size, and microscopic stress in polycrystalline thin films. In this study, we investigated the generation and temporal evolution of texture, grain size, and internal stress in cathodic arc evaporated Al0.50Ti0.50N thin films using a bespoke deposition apparatus designed for use with 2-dimensional synchrotron x-ray diffraction technique. The influence of the substrate temperature is investigated in terms of the emergence and development of texture, grain size and stress evolution. A dynamic evolution of the crystallographic texture is observed as the overall film thickness varies. We clearly resolved two regime of films growth based on stress evolution. Beyond a threshold grain size (similar to 14 nm), the stress scales inversely to the average grain sizes, and as the film thickness increases, immediate compressive stress relaxation was seen. An extensive ex-situ evaluation of thin films using electron microscopies and electron diffraction was performed to support the in-situ x-ray diffraction results.

  • 2.
    Linder, Clara
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. RISE, Corrosion, Vehicles and Surface Protection, Kista, 164 40, Sweden.
    Gangaprasad Rao, Smita
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    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.
    Munktell, Sara
    Swerim AB, Metallic materials in corrosive environments, Kista, 164 40, Sweden.
    Le Febvrier, Arnaud
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Björk, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Effect of Mo content on the corrosion resistance of (CoCrFeNi)1−xMox thin films in sulfuric acid2024Ingår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 790, artikel-id 140220Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    (CoCrFeNi)1−xMox thin films with various Mo content (0–10 at.%) were grown by magnetron sputtering on a stainless steel substrate. The films with 0–2 at.% presented two crystal structures: one FCC phase and one sigma phase, while films with higher Mo content only had the FCC structure. All films have a (111) texture and follow the topography of the substrate. The corrosion resistance of the films was evaluated in 0.05 M H2SO4 at room temperature and at 80 °C. It was observed that the corrosion current densities considerably decreased for Mo > 2 at%, and that the current densities were higher at the elevated temperature. Scanning Kelvin Probe Force Microscopy showed a large potential difference between the main FCC phase and sigma phase for the Mo0–2 films. This would suggest that preferential dissolution of the FCC phase occurs over the sigma and reduces the corrosion resistance. Such preferential dissolution does not occur for the higher Mo content films with only the FCC phase. The high corrosion resistance was also attributed to the inhibition of Fe and Cr dissolution by Mo and the stabilisation of the Cr enriched oxide by incorporating Mo oxides into the passive film, identified by X-ray photoelectron spectroscopy. The low corrosion current densities (below 1 µA/cm2) make these thin films possible candidates for protective coatings of bipolar plates in PEM fuel cells.

  • 3.
    Pankratova, Daria
    et al.
    Lulea Univ Technol, Sweden.
    Yusupov, Khabib
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materialdesign. Linköpings universitet, Tekniska fakulteten.
    Vomiero, Alberto
    Lulea Univ Technol, Sweden; Ca Foscari Univ Venice, Italy.
    Honnali, Sanath Kumar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Fournier, Daniele
    Sorbonne Univ, France.
    Ekeroth, Sebastian
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Azina, Clio
    9165 RWTH Aachen Univ, Germany.
    Le Febvrier, Arnaud
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Enhanced Thermoelectric Properties by Embedding Fe Nanoparticles into CrN Films for Energy Harvesting Applications2024Ingår i: ACS Applied Nano Materials, E-ISSN 2574-0970, Vol. 7, nr 3, s. 3428-3435Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nanostructured materials and nanocomposites have shown great promise for improving the efficiency of thermoelectric materials. Herein, Fe nanoparticles were imbedded into a CrN matrix by combining two physical vapor deposition approaches, namely, high-power impulse magnetron sputtering and a nanoparticle gun. The combination of these techniques allowed the formation of nanocomposites in which the Fe nanoparticles remained intact without intermixing with the matrix. The electrical and thermal transport properties of the nanocomposites were investigated and compared to those of a monolithic CrN film. The measured thermoelectric properties revealed an increase in the Seebeck coefficient, with a decrease of hall carrier concentration and an increase of the electron mobility, which could be explained by energy filtering by internal phases created at the NP/matrix interface. The thermal conductivity of the final nanocomposite was reduced from 4.8 W m(-1) K-1 to a minimum of 3.0 W m(-1) K-1. This study shows prospects for the nanocomposite synthesis process using nanoparticles and its use in improving the thermoelectric properties of coatings.

  • 4.
    Niiranen, Pentti
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Nadhom, Hama
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Zanaska, Michal
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Sortica, Mauricio
    Uppsala Univ, Sweden.
    Primetzhofer, Daniel
    Uppsala Univ, Sweden.
    Lundin, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Biased quartz crystal microbalance method for studies of chemical vapor deposition surface chemistry induced by plasma electrons2023Ingår i: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 94, nr 2, artikel-id 023902Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A recently presented chemical vapor deposition (CVD) method involves using plasma electrons as reducing agents for deposition of metals. The plasma electrons are attracted to the substrate surface by a positive substrate bias. Here, we present how a standard quartz crystal microbalance (QCM) system can be modified to allow applying a DC bias to the QCM sensor to attract plasma electrons to it and thereby also enable in situ growth monitoring during the electron-assisted CVD method. We show initial results from mass gain evolution over time during deposition of iron films using the biased QCM and how the biased QCM can be used for process development and provide insight into the surface chemistry by time-resolving the CVD method. Post-deposition analyses of the QCM crystals by cross-section electron microscopy and high-resolution x-ray photoelectron spectroscopy show that the QCM crystals are coated by an iron-containing film and thus function as substrates in the CVD process. A comparison of the areal mass density given by the QCM crystal and the areal mass density from elastic recoil detection analysis and Rutherford backscattering spectrometry was done to verify the function of the QCM setup. Time-resolved CVD experiments show that this biased QCM method holds great promise as one of the tools for understanding the surface chemistry of the newly developed CVD method.

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  • 5.
    Wu, Zhixing
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Ding, Penghui
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Gueskine, Viktor
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Glowacki, Eric Daniel
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Crispin, Xavier
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Björk, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Vagin, Mikhail
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik.
    Conducting Polymer‐Based e‐Refinery for Sustainable Hydrogen Peroxide Production2023Ingår i: Energy & Environmental Materials, E-ISSN 2575-0356, artikel-id e12551Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electrocatalysis enables the industrial transition to sustainable production of chemicals using abundant precursors and electricity from renewable sources. De-centralized production of hydrogen peroxide (H2O2) from water and oxygen of air is highly desirable for daily life and industry. We report an effective electrochemical refinery (e-refinery) for H2O2 by means of electrocatalysis-controlled comproportionation reaction (2(H)O + O -> 2(HO)), feeding pure water and oxygen only. Mesoporous nickel (II) oxide (NiO) was used as electrocatalyst for oxygen evolution reaction (OER), producing oxygen at the anode. Conducting polymer poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) drove the oxygen reduction reaction (ORR), forming H2O2 on the cathode. The reactions were evaluated in both half-cell and device configurations. The performance of the H2O2 e-refinery, assembled on anion-exchange solid electrolyte and fed with pure water, was limited by the unbalanced ionic transport. Optimization of the operation conditions allowed a conversion efficiency of 80%.

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  • 6.
    Du, Hao
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten. Guizhou Univ, Peoples R China; Guizhou Univ, Peoples R China.
    Shu, Rui
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Le Febvrier, Arnaud
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Sortica, Mauricio A.
    Uppsala Univ, Sweden.
    Primetzhofer, Daniel
    Uppsala Univ, Sweden; Uppsala Univ, Sweden.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Lundin, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Corundum-structured AlCrNbTi oxide film grown using high-energy early-arriving ion irradiation in high-power impulse magnetron sputtering2023Ingår i: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 234, artikel-id 115578Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multicomponent or high-entropy oxide films are of interest due to their remarkable structure and properties. Here, energetic ion irradiation is utilized for controlling the phase formation and structure of AlCrNbTi oxide at growth temperature of 500 degrees C. The ion acceleration is achieved by using a high-power impulse magnetron sputtering (HiPIMS) discharge, accompanied by a 10 & mu;s-long synchronized substrate bias (Usync), to minimize the surface charging effect and accelerate early-arriving ions, mainly Al+, O+, Ar2+, and Al2+. By increasing the magnitude of Usync from-100 V to-500 V, the film structure changes from amorphous to single-phase corundum, followed by the formation of high-number-density stacking faults (or nanotwins) at Usync =-500 V. This approach paves the way to tailor the high-temperature-phase and defect formation of oxide films at low growth temperature, with prospects for use in protective-coating and dielectric applications.

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  • 7.
    Hsu, Tun-Wei
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Kolozsvári, Szilárd
    Plansee Composite Materials GmbH, Lechbruck am See, DE-86983, Germany.
    Polcik, Peter
    Plansee Composite Materials GmbH, Lechbruck am See, DE-86983, Germany.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Dense and hard TiWC protective coatings grown with tungsten ion irradiation using WC-HiPIMS/TiC-DCMS co-sputtering technique without external heating2023Ingår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 618, artikel-id 156639Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Titanium tungsten carbide (TiWC) coatings are deposited by a combined high-power impulse and dc magnetron co-sputtering (HiPIMS/DCMS) technique. No external heating is applied during deposition phase, instead, the thermally driven adatom mobility is substituted by heavy ion irradiation. DCMS sources equipped with titanium carbide targets provide constant neutral fluxes to establish the predominant coating structures, whereas tungsten carbide target in HiPIMS mode serves as the source of heavy metal-ions. Substrate bias of −60 V is synchronized to W+ ion-rich time domains of HiPIMS pulses to minimize the contribution from working gas ions. The influence of W+ ion flux intensity, controlled by varying peak target current density (JT), on film properties is investigated. X-ray photoelectron spectroscopy reveals the presence of over stoichiometric carbon forming an amorphous phase, the amount of which can be fine-tuned by varying JT. Changes in film composition as a function of JT are explained based on the in-situ ion mass spectroscopy analyses. Dense TiWC coatings by hybrid process exhibit hardness higher than 30 GPa, which are comparable to TiWC films deposited by DCMS with dc substrate bias and external heating. The relative energy consumption in the hybrid process is reduced by 77 % as compared to high-temperature DCMS processing.

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  • 8.
    Wu, Zhixing
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Vagin, Mikhail
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Ding, Penghui
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Leanderson, Per
    Linköpings universitet, Institutionen för hälsa, medicin och vård, Avdelningen för prevention, rehabilitering och nära vård. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Medicincentrum, Arbets- och miljömedicin.
    Kozyatnyk, Ivan
    Linköpings universitet, Institutionen för hälsa, medicin och vård, Avdelningen för prevention, rehabilitering och nära vård. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Medicincentrum, Arbets- och miljömedicin.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Björk, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Effect of Product Removal in Hydrogen Peroxide Electrosynthesis on Mesoporous Chromium(III) Oxide2023Ingår i: ACS Applied Nano Materials, E-ISSN 2574-0970, Vol. 6, nr 20, s. 18748-18756Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    On-site electrosynthesis of hydrogen peroxide (H2O2) is a promising alternative technology to the conversional centralized anthraquinone oxidation process. Here, we report a platinum group metal (PGM)-free H2O2 electrogenerator with mesoporous Cr2O3 and NiCo2O4 used as electrocatalysts for oxygen reduction and evolution reactions (ORR and OER), respectively. The catalysts were synthesized via a hydrothermal synthesis route and had pore sizes of 3 and 7 nm and specific surface areas of 112 and 62 m(2) g(-1), respectively. Mesoporous Cr2O3 was evaluated in a half cell with 0.1 M KOH for electrocatalytic oxygen reduction, which shows 2.2 transferred electrons per oxygen and an in situ H2O2 yield of 70%. This enables the electrosynthesis of hydrogen peroxide in alkaline medium using Cr2O3 as a 2e-ORR-H2O2 electrocatalyst, with oxygen evolution as an auxiliary reaction on NiCo2O4. The effect of electrolyte flow on the H2O2 electrogenerator was investigated. It is observed that one-way feeding of the catholyte suppresses deterioration of the electrocatalyst and allows a faradic conversion up to similar to 90% with a production rate of similar to 0.36 [g (h<middle dot>g(cat))(-1)], operating within the cell voltage of 1.2 V. This work demonstrates both a viable method for electrosynthesis of H2O2 production using PGM-free electrocatalysts and the possibility to obtain a high faradic efficiency by mitigating the effect from catalyst degradation.

  • 9.
    Hsu, Tun-Wei
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Christensen, Bjarke Holl
    Danish Technological Institute, Kongsvang Allé 29, DK-8000 Aarhus C, Denmark.
    Almtoft, Klaus Pagh
    Danish Technological Institute, Kongsvang Allé 29, DK-8000 Aarhus C, Denmark.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Kolozsvári, Szilárd
    Plansee Composite Materials GmbH, Lechbruck am See DE-86983, Germany.
    Polcik, Peter
    Plansee Composite Materials GmbH, Lechbruck am See DE-86983, Germany.
    Bolz, Stephan
    CemeCon AG, Adenauerstr. 20 A4, D-52146 Wűrselen, Germany.
    Kölker, Werner
    CemeCon AG, Adenauerstr. 20 A4, D-52146 Wűrselen, Germany.
    Schiffers, Christoph
    CemeCon AG, Adenauerstr. 20 A4, D-52146 Wűrselen, Germany.
    Mesic, Biljana
    CemeCon AG, Adenauerstr. 20 A4, D-52146 Wűrselen, Germany.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Effects of substrate rotation during AlSi-HiPIMS/Ti-DCMS co-sputtering growth of TiAlSiN coatings on phase content, microstructure, and mechanical properties2023Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 453, artikel-id 128986Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A combined high-power impulse and dc magnetron co-sputtering (HiPIMS/DCMS) technique is used to deposit Ti0.6Al0.32Si0.08N films with 1-fold substrate table rotation. Layers are grown at two different substrate-target separations, two different rotational speeds, and with different values of substrate bias. The aim is to study the role of (1) overlap between ion and neutral fluxes generated from HiPIMS and DCMS sources, respectively, and (2) the subplantation range of low-mass ions. Results from X-ray diffractometry highlight the necessity of flux intermixing in the formation of the metastable B1-structured TiAlSiN solid solutions. All films grown at short target-to-substrate distance contain the hexagonal AlN phase, as there is essentially no overlap between HiPIMS and DCMS fluxes, thus the Al+ and Si+ subplantation is very limited. Under conditions of high flux intermixing corresponding to larger target-to-substrate distance, no w-AlN forms irrespective of rotational speed (1 or 3 rpm) and bias amplitude (120 or 480 V), indicating that the role of Al+/Si+ and Ti flux overlap is crucial for the phase formation during film growth by HiPIMS/DCMS with substrate rotation. This conclusion is further supported by the fact that the reduction of the bilayer thickness with increasing the target-to-substrate distance (hence increasing flux overlap) is larger for films grown with higher amplitude of the substrate bias, indicative of more efficient Al+/Si+ subplantation into the c-TiN phase. Single-phase films with the hardness close to that of layers grown with stationary substrate table can be achieved, however, at the expense of higher compressive stress.

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  • 10.
    Du, Hao
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten. Guizhou Univ, Peoples R China; Guizhou Univ, Peoples R China.
    Shu, Rui
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Le Febvrier, Arnaud
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Lundin, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Evolution of microstructure and properties of TiNbCrAlHfN films grown by unipolar and bipolar high-power impulse magnetron co-sputtering: The role of growth temperature and ion bombardment2023Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 459, artikel-id 129389Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Growth temperature (Ts) and ion irradiation energy (Ei) are important factors that influence film growth as well as their properties. In this study, we investigate the evolution of crystal structure and residual stress of TiNb-CrAlHfN films under various Ts and Ei conditions, where the latter is mainly controlled by tuning the flux of sputtered Hf ions using bipolar high-power impulse magnetron (BP-HiPIMS). The results show that TiNbCrAlHfN films exhibit the typical FCC NaCl-type structure. By increasing Ts from room temperature to 600 degrees C, the film texture changes from high-surface-energy (111) to low-surface-energy (100) accompanied by a higher crystal-linity in the out-of-plane direction and a more disordered growth tilt angle to the surface plane. In addition, compressive stress decreases with increasing Ts, which is ascribed to changes in the film growth both in the early and post-coalescence stages and more tensile thermal stress at elevated Ts. In contrast, a clear texture transition window is seen under various Ei of Hf+ ions, i.e., high-surface-energy planes change to low-surface-energy planes as Ei exceeds-110 eV, while low-surface-energy planes gradually transform back to high-surface-energy planes when Ei increases from 210 to 260 eV, indicating renucleation events for Ei > 210 eV. Compressive stress in-creases with increasing Ei but is still lower than that of a reference series with DC substrate bias UDC =-100 V. The study shows that it is possible to tailor properties of FCC-structured high-entropy nitrides by varying Ts and Ei in a similar fashion to conventional transition metal nitrides using the approach of unipolar and bipolar HiPIMS co-sputtering.

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  • 11.
    Gangaprasad Rao, Smita
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Illgner, Pascal Manuel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Nagy, Gyula
    Uppsala Univ, Sweden.
    Djemia, Philippe
    Univ Sorbonne Paris Nord, France.
    Primetzhofer, Daniel
    Uppsala Univ, Sweden.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA.
    Le Febvrier, Arnaud
    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.
    Low temperature epitaxial growth of Cantor-nitride thin films by magnetic field assisted magnetron sputtering2023Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 41, nr 5, artikel-id 053415Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Low-temperature epitaxial growth of multicomponent alloy-based thin films remains an outstanding challenge in materials science and is important for established fundamental properties of these complex materials. Here, Cantor nitride (CrMnFeCoNi)N thin films were epitaxially grown on MgO(100) substrates at low deposition temperature by magnetic-field-assisted dc-magnetron sputtering, a technique where a magnetic field is applied to steer the dense plasma to the substrate thereby influencing the flux of Ar-ions bombarding the film during growth. Without ion bombardment, the film displayed textured growth. As the ion flux was increased, the films exhibited epitaxial growth. The epitaxial relationship between film and substrate was found to be cube on cube (001)film parallel to(001)MgO, [100]film parallel to[100]MgO. The epitaxy was retained up to a thickness of approximately similar to 100 nm after which the growth becomes textured with a 002 out-of-plane orientation. The elastic constants determined by Brillouin inelastic light scattering were found to be C-11 = 320 GPa, C-12 = 125 GPa, and C-44 = 66 GPa, from which the polycrystalline Youngs modulus was calculated as 204 GPa and Poissons ratio = 0.32, whereas available elastic properties still remained very scarce. (c) 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

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  • 12.
    Gangaprasad Rao, Smita
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Mukhamedov, Boburjon
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Nagy, Gyula
    Uppsala Univ, Sweden.
    Tseng, Eric Nestor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Shu, Rui
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Primetzhofer, Daniel
    Uppsala Univ, Sweden.
    Persson, Per O A
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Alling, Björn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Abrikosov, Igor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Le Febvrier, Arnaud
    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.
    Phase formation in CrFeCoNi nitride thin films2023Ingår i: Physical Review Materials, E-ISSN 2475-9953, Vol. 7, nr 4, artikel-id 055002Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As a single-phase alloy, CrFeCoNi is a face centered cubic (fcc) material related to the archetypical highentropy Cantor alloy CrFeCoNiMn. For thin films, CrFeCoNi of approximately equimolar composition tends to assume an fcc structure when grown at room temperature by magnetron sputtering. However, the single-phase solid solution state is typically not achieved for thin films grown at higher temperatures. The same holds true for Cantor alloy-based ceramics (nitrides and oxides), where phase formation is extremely sensitive to process parameters such as the amount of reactive gas. This study combines theoretical and experimental methods to understand the phase formation in nitrogen-containing CrFeCoNi thin films. Density functional theory calculations considering three competing phases (CrN, Fe-Ni and Co) show that the free energy of mixing, Delta G of (CrFeCoNi)(1-x)N-x solid solutions has a maximum at x = 0.20-0.25, and AG becomes lower when x < 0.20 and x > 0.25. Thin films of (CrFeCoNi)1-xNx (0.14 >= x <= 0.41) grown by magnetron sputtering show stabilization of the metallic fcc when x <= 0.22 and the stabilization of the NaCl B1 structure when x > 0.33, consistent with the theoretical prediction. In contrast, films with intermediate amounts of nitrogen (x = 0.22) grown at higher temperatures show segregation into multiple phases of CrN, Fe-Ni-rich and Co. These results offer an explanation for the requirement of kinetically limited growth conditions at low temperature for obtaining single-phase CrFeCoNi Cantor-like nitrogen-containing thin films and are of importance for understanding the phase-formation mechanisms in multicomponent ceramics. The results from the study further aid in making correlations between the observed mechanical properties and the crystal structure of the films.

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  • 13.
    Wu, Zhixing
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Vagin, Mikhail
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Ding, Penghui
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Pshyk, Oleksandr
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Björk, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Selectivity Control of Oxygen Reduction Reaction over Mesoporous Transition Metal Oxide Catalysts for Electrified Purification Technologies2023Ingår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 15, nr 21, s. 26093-26103Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Direct electrification of oxygen-associated reactionscontributesto large-scale electrical storage and the launch of the green hydrogeneconomy. The design of the involved catalysts can mitigate the electricalenergy losses and improve the control of the reaction products. Weevaluate the effect of the interface composition of electrocatalystson the efficiency and productivity of the oxygen reduction reaction(ORR) and oxygen evolution reaction (OER), both mechanistically andat device levels. The ORR and OER were benchmarked on mesoporous nickel-(II)oxide and nickel cobaltite (NiO and NiCo2O4,respectively) obtained by a facile template-free hydrothermal synthesis.Physicochemical characterization showed that both NiO and NiCo2O4 are mesoporous and have a cubic crystal structurewith abundant surface hydroxyl species. NiCo2O4 showed higher electrocatalytic activity in OER and selectivity towater as the terminal product of ORR. On the contrary, ORR over NiOyielded hydroxyl radicals as products of a Fenton-like reaction ofH(2)O(2). The product selectivity in ORR was usedto construct two electrolyzers for electrified purification of oxygenand generation of hydroxyl radicals.

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  • 14.
    Wu, Zhixing
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Vagin, Mikhail
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Ding, Penghui
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Björk, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Bifunctional Mesoporous MO x (M = Cr, Fe, Co, Ni, Ce) Oxygen Electrocatalysts for Platinum Group Metal-Free Oxygen Pumps2022Ingår i: Energy Technology, ISSN 2194-4288, E-ISSN 2194-4296, Vol. 10, nr 12, artikel-id 2200927Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bifunctional electrocatalysts with both accelerated oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) enable high-power density electricity storage and decentralized extraction of pure oxygen from air for usage in health care. Herein, a hydrothermal synthesis employing the anionic surfactant sodium dodecyl sulfate as structure-directing agent is developed to fabricate a family of crystalline mesoporous metal oxides (meso-MO X , M = Cr, Fe, Co, Ni, Ce). The pore size and specific surface area depend on the metal used and they range from 3 to 6 nm and 60 to 200 m(2) g(-1), respectively. NiO and Co3O4 show a higher catalytic efficiency in alkaline media in comparison with the other oxides studied, and their activities are comparable with the values reported for platinum group metal (PGM)-based electrocatalysts. This stems from lower voltage losses and by the presence of specific hydroxide adsorbates on the surface. Both ORR and OER driven on Co3O4 show the unified rate-determining chemical step (|OO-|(center dot) (ads) + H2O <-> |OOH|(center dot) (ads) + OH-, where | X | ads are the species adsorbed on active sites). The bifunctional ORR/OER electrocatalysis obtained on mesoporous NiO is utilized for the first symmetrical PGM-free oxygen pump fed by air and water only.

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  • 15.
    Eriksson, Peter
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Truong, Anh H. T.
    Nanyang Technol Univ, Singapore.
    Brommesson, Caroline
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Du Rietz, Anna
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Kokil, Ganesh R.
    Univ Queensland, Australia.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Hu, Zhang-Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Dang, Tram T.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Persson, Per O A
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Uvdal, Kajsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Cerium Oxide Nanoparticles with Entrapped Gadolinium for High T-1 Relaxivity and ROS-Scavenging Purposes2022Ingår i: ACS Omega, E-ISSN 2470-1343, Vol. 7, nr 24, s. 21337-21345Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Gadolinium chelates are employed worldwide today as clinical contrast agents for magnetic resonance imaging. Until now, the commonly used linear contrast agents based on the rare-earth element gadolinium have been considered safe and well-tolerated. Recently, concerns regarding this type of contrast agent have been reported, which is why there is an urgent need to develop the next generation of stable contrast agents with enhanced spin-lattice relaxation, as measured by improved T-1 relaxivity at lower doses. Here, we show that by the integration of gadolinium ions in cerium oxide nanoparticles, a stable crystalline 5 nm sized nanoparticulate system with a homogeneous gadolinium ion distribution is obtained. These cerium oxide nanoparticles with entrapped gadolinium deliver strong T-1 relaxivity per gadolinium ion (T-1 relaxivity, r(1) = 12.0 mM(-1) s(-1)) with the potential to act as scavengers of reactive oxygen species (ROS). The presence of Ce3+ sites and oxygen vacancies at the surface plays a critical role in providing the antioxidant properties. The characterization of radial distribution of Ce3+ and Ce4+ oxidation states indicated a higher concentration of Ce3+ at the nanoparticle surfaces. Additionally, we investigated the ROS-scavenging capabilities of pure gadolinium-containing cerium oxide nanoparticles by bioluminescent imaging in vivo, where inhibitory effects on ROS activity are shown.

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  • 16.
    Linder, Clara
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. RISE, Sweden.
    Gangaprasad Rao, Smita
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik.
    Le Febvrier, Arnaud
    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.
    Munktell, Sara
    Swerim AB, Sweden.
    Björk, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Corrosion Resistance and Catalytic Activity toward the Oxygen Reduction Reaction of CoCrFexNi (0 < x < 0.7) Thin Films2022Ingår i: ACS Applied Energy Materials, E-ISSN 2574-0962, Vol. 5, nr 9, s. 10838-10848Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Corrosion resistance and catalytic activity toward the oxygen reduction reaction (ORR) in an alkaline environment are two key properties for water recombination applications. In this work, CoCrFexNi (0 &lt;= x &lt;= 0.7) thin films were deposited by magnetron sputtering on polished steel substrates. The native passive layer was 2-4 nm thick and coherent to the columnar grains determined by transmission electron microscopy. The effect of Fe on the corrosion properties in 0.1 M NaCl and 1 M KOH and the catalytic activity of the films toward ORR were investigated. Electrochemical impedance spectroscopy and potentiodynamic polarization measurements indicate that CoCrFe0.7Ni and CoCrFe0.3Ni have the highest corrosion resistance of the studied films in NaCl and KOH, respectively. The high corrosion resistance of the CoCrFe0.7Ni film in NaCl was attributed to the smaller overall grain size, which leads to a more homogeneous film with a stronger passive layer. For CoCrFe0.3Ni in KOH, it was attributed to a lower Fe dissolution into the electrolyte and the build-up of a thick and protective hydroxide layer. Scanning Kelvin probe force microscopy showed no potential differences globally in any of the films, but locally, a potential gradient between the top of the columns and grain boundaries was observed. Corrosion of the films was likely initiated at the top of the columns where the potential was lowest. It was concluded that Fe is essential for the electrochemical activation of the surfaces and the catalytic activity toward ORR in an alkaline medium. The highest catalytic activity was recorded for high Fe-content films (x &gt;= 0.5) and was attributed to the formation of platelet-like oxide particles on the film surface upon anodization. The study showed that the combination of corrosion resistance and catalytic activity toward ORR is possible for CoCrFexNi, making this material system a suitable candidate for water recombination in an alkaline environment.

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  • 17.
    Lai, Chung-Chuan
    et al.
    European Spallat Source ERIC ESS, Sweden.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Svensson, Per-Olof
    European Spallat Source ERIC ESS, Sweden.
    Höglund, Carina
    European Spallat Source ERIC ESS, Sweden; Impact Coatings AB, S-58216 Linkoping, Sweden.
    Robinson, Linda
    European Spallat Source ERIC ESS, Sweden.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hall-Wilton, Richard
    European Spallat Source ERIC ESS, Sweden; Univ Milano Bicocca, Italy.
    Effect of substrate roughness and material selection on the microstructure of sputtering deposited boron carbide thin films2022Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 433, artikel-id 128160Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Amorphous boron carbide (B4C) thin films are by far the most popular form for the neutron converting layers in the 10B-based neutron detectors, which are a rising trend in detector technologies in response to the increasing scarcity and price of 3He, the standard material for neutron detection. The microstructure of the B4C films is closely related to the important properties, e.g. density and adhesion, for the converting layers, which eventually affect the detection efficiency and the long-term stability of the detectors. To study the influence from substrates of different roughness and materials, the B4C films were deposited on polished Si substrates with Al, Ti, and Cu buffer layers and unpolished Si, Al, Ti, and Cu substrates by direct current magnetron sputtering at a substrate temperature of 623 K. The tapered columnar grains and nodular defects, generally observed in SEM images, indicated a strong shadowing effect where voids were introduced around the grains. The change in the grain size did not show a direct dependence to the substrate roughness, acquired from the surface profile, nor to the mass density of the films, obtained from reflectivity patterns. However, films with non-uniform size of columnar grains were deposited on substrates with high skewness, leading to a drop of mass density from ∼95% down to ∼70% of tabulated bulk density. On the other hand, similar microstructures and mass density were obtained from the films deposited on Al, Ti, and Cu of different roughness and good adhesion were observed from cross-cut adhesion tests, showing the reliability of sputtering deposited B4C films on common structural materials in neutron detectors.

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  • 18.
    Salamania, Janella
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Sangiovanni, Davide Giuseppe
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Kraych, A.
    The Interdisciplinary Centre for Advanced Materials Simulation (ICAMS), Ruhr-Universität Bochum, Bochum, Germany.
    Calamba Kwick, K.M.
    Sandvik Coromant AB, Stockholm, Sweden.
    Schramm, I.C.
    Sandvik Coromant AB, Stockholm, Sweden.
    Johnson, L.J.S.
    Sandvik Coromant AB, Stockholm, Sweden.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hsu, Tun-Wei
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Mrovec, M.
    The Interdisciplinary Centre for Advanced Materials Simulation (ICAMS), Ruhr-Universität Bochum, Bochum, Germany.
    Rogström, Lina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Tasnadi, Ferenc
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Abrikosov, Igor A.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Elucidating dislocation core structures in titanium nitride through high-resolution imaging and atomistic simulations2022Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 224, artikel-id 111327Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Although titanium nitride (TiN) is among the most extensively studied and thoroughly characterizedthin-film ceramic materials, detailed knowledge of relevant dislocation core structures is lacking. Byhigh-resolution scanning transmission electron microscopy (STEM) of epitaxial single crystal (001)-oriented TiN films, we identify different dislocation types and their core structures. These include, besidesthe expected primary a/2{110}h110i dislocation, Shockley partial dislocations a/6{111}h112i and sessileLomer edge dislocations a/2{100}h011i. Density-functional theory and classical interatomic potentialsimulations complement STEM observations by recovering the atomic structure of the different disloca-tion types, estimating Peierls stresses, and providing insights on the chemical bonding nature at the core.The generated models of the dislocation cores suggest locally enhanced metal–metal bonding, weakenedTi-N bonds, and N vacancy-pinning that effectively reduces the mobilities of {110}h110i and {111}h112idislocations. Our findings underscore that the presence of different dislocation types and their effects onchemical bonding should be considered in the design and interpretations of nanoscale and macroscopicproperties of TiN.

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  • 19.
    Wu, Zhixing
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Vagin, Mikhail
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Björk, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Morphology effects on electrocatalysis of anodic water splitting on nickel (II) oxide2022Ingår i: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 333, artikel-id 111734Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Oxygen evolution reaction (OER) is critical for producing high purity hydrogen and oxygen via electrocatalytic water splitting. In this work, single crystalline, nanoporous nickel oxide (NiO) was prepared using a hydro thermal, soft-templated synthesis route followed by calcination at different temperatures. It is shown that the NiO crystals have a cubic lattice, and the pore size can be tuned from similar to 1 to similar to 70 nm by varying the calcination temperature, i.e. variation from micro to macroporosity. The NiOs catalytic performance as electrocatalysts was evaluated in OER, both thermodynamically and kinetically. Mesoporous NiO with calcination temperature of 400 degrees C had the lowest overpotential (335 mV) required @ 10 mA/cm(2) accompanied with the highest turnover frequency value and mass activity among of the obtained NiO electrocatalysts. The study shows that the electrocatalytic activity of nanoporous NiO outperforms that of commercial catalyst Ir/C (similar to 360 mV @ 10 mA/cm(2)). Microporous NiO possess the highest specific surface area and electrical double layer capacitance, while the nonporous NiO particles have the highest specific activity and BET activity of the catalysts. It is concluded that the minimization of voltage losses by the nanoscale enlargement of the electrocatalyst surface area shows the coherence between gas adsorption and electrocapacitive measurements. Conversely, the OER kinetics showed deterioration with surface area maximization due to the impediment of ionic transport inside the micropores. This work demonstrates the importance of morphology optimization to obtain an efficient OER electrocatalyst with low required overpotential and kinetic loss.

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  • 20.
    Gangaprasad Rao, Smita
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Shu, Rui
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Le Febvrier, Arnaud
    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.
    Plasma diagnostics and film growth of multicomponent nitride thin films with magnetic-field-assisted-dc magnetron sputtering2022Ingår i: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 204, artikel-id 111331Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    During direct current magnetron sputtering (dcMS) of thin films, the ion energy and flux are complex parameters that influence thin film growth and can be exploited to tailor their properties. The ion energy is generally controlled by the bias voltage applied at the substrate. The ion flux density however is controlled by more complex mechanisms. In this study, we look into magnetic-field-assisted dcMs, where a magnetic field applied in the deposition chamber by use of a solenoid coil at the substrate position, influences the energetic bombardment by Ar ions during deposition. Using this technique, CrFeCoNi multicomponent nitride thin films were grown on Si(100) substrates by varying the bias voltage and magnetic field systematically. Plasma diagnostics were performed by a Langmuir wire probe and a flat probe. On interpreting the data from the current-voltage curves it was confirmed that the ion flux at the substrate increased with increasing coil magnetic field with ion energies corresponding to the applied bias. The increased ion flux assisted by the magnetic field produced by the solenoid coil aids in the stabilization of NaCl B1 crystal structure without introducing Ar ion implantation.

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  • 21.
    Paschalidou, Eirini-Maria
    et al.
    Uppsala Univ, Sweden.
    Shu, Rui
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Papaderakis, Athanasios A.
    Univ Manchester, England; Univ Manchester, England.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Le Febvrier, Arnaud
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    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.
    Nyholm, Leif
    Uppsala Univ, Sweden.
    The effect of the Nb concentration on the corrosion resistance of nitrogen-containing multicomponent TiZrTaNb-based films in acidic environments2022Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 927, artikel-id 167005Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multicomponent as well as high-entropy-based nitrides have received increasing interest in the field of materials science and engineering. The structural characteristics of these compounds result in a mix of covalent, metallic, and ionic bonds that give rise to a number of attractive properties including high hardness, electrical and thermal conductivities as well as chemical stability. These properties render these materials promising candidates for various industrial applications involving harsh operating conditions. Herein, the corrosion resistances of dc magnetron sputtered nitrogen-containing TiZrTaNby thin films with Nb content ranging from 8.0 to 24.5 at% have been investigated to provide insights regarding the corrosion resistances of multicomponent systems containing more than one passive element. The corrosion resistances and anodic behavior of the films were examined by electrochemical means in 0.1 M H2SO4 and 0.1 M HCl solutions. The results demonstrate that despite the significant differences in the concentration of one of the two main passive elements in the films i.e., Nb, the corrosion resistance did not differ significantly between the films. To provide insights into this phenomenon, the surface chemical state and composition of the prepared films were probed using X-ray photoelectron spectroscopy. It was shown that all samples exhibited Ta-rich surfaces after positive polarization up to 3.0 V vs. Ag/AgCl (3 M NaCl) as a result of the anodic dissolution of Zr and Ti. The thickness of the oxide layer formed upon different anodic polarization was studied using transmission electron microscopy, while complementary electrochemical impedance studies were performed. The extent of Nb dissolution from the surface of the films was, on the other hand, found to be small. These findings highlight the dominant role of Ta in the passivation of the films and demonstrate the minor effect of Nb concentration on the corrosion resistances of the films. However, it was demonstrated that the presence of Nb was still important for the corrosion resistance of the films above 1.4 V vs. Ag/AgCl (3 M NaCl), when replacing Nb with Cr, due to transpassive dissolution of Cr. These results facilitate the design of highly corrosion resistant multicomponent nitrides containing more than one passive element.(c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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  • 22.
    Gangaprasad Rao, Smita
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Shu, Rui
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Le Febvrier, Arnaud
    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.
    The effects of copper addition on phase composition in (CrFeCo)1-yNy multicomponent thin films2022Ingår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 572, artikel-id 151315Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Cantor alloy CrFeCoMnNi is generally fcc structured, but moderate changes in the composition can have a large influence on the phase formation. The aim of this study was to understand the changes brought on in lownitrogen-containing (CrFeCo)1-yNy thin films with y = 0.19 on the addition of copper, an interesting metal in terms of atomic size and nitride formation enthalpy. (CrFeCoCux)1-yNy films were grown by reactive magnetron sputtering. The amount of copper in the films was increased from x = 0 to x = 0.15 to study competitive phase formation. Without Cu, two-phase fcc + bcc films were obtained. The addition of Cu was found to stabilize the bcc structure despite the fact that Cu as a pure metal is fcc. Nanoindentation tests showed slight increase in hardness with initial Cu addition from 11 GPa to 13.7 +/- 0.2 GPa. The occurrence of pile up as opposed to cracking is an indication of the films ductility.

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  • 23.
    Gangaprasad Rao, Smita
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Shu, Rui
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Wang, Siyang
    Imperial Coll London, England.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Giuliani, Finn
    Imperial Coll London, England.
    Le Febvrier, Arnaud
    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.
    Thin film growth and mechanical properties of CrFeCoNi/TiNbZrTa multilayers2022Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 224, artikel-id 111388Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multilayers of high entropy alloys (HEA) are picking up interest due to the possibility of altering material properties by tuning crystallinity, thickness, and interfaces of the layers. This study investigates the growth mechanism and mechanical properties of CrFeCoNi/TiNbZrTa multilayers grown by magnetron sputtering. Multilayers of bilayer thickness (A) from 5 nm to 50 nm were grown on Si(1 0 0) substrates. Images taken by transmission electron microscopy and energy-dispersive X-ray spectroscopy mapping revealed that the layers were well defined with no occurrence of elemental mixing. Multilayers with A &lt; 20 nm exhibited an amorphous structure. As A increased, the CrFeCoNi layer displayed a higher crystallinity in comparison to the amorphous TiNbZrTa layer. The mechanical properties were influenced by the crystallinity of the layers and stresses in the film. The film with A = 20 nm had the highest hardness of approximately 12.5 GPa owing grain refinement of the CrFeCoNi layer. An increase of A &gt;= 30 nm resulted in a drop in the hardness due to the increase in crystal domains of the CrFeCoNi layer. Micropillar compression induced shear in the material rather than fracture, along with elemental intermixing in the core of the deformed region of the compressed micropillar.

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  • 24.
    Moreno, Maiara
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Andersson, Jon M.
    Seco Tools AB, Sweden.
    Johansson, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Seco Tools AB, Sweden.
    Friedrich, Birgit E.
    Seco Tools AB, Sweden.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Schramm, Isabella C.
    Sandvik Coromant, Sweden.
    Johnson, Lars J. S.
    Sandvik Coromant, Sweden.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Rogström, Lina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Wear of Mo- and W-alloyed TiAlN coatings during high-speed turning of stainless steel2022Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 446, artikel-id 128786Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study investigates the wear of W- and Mo-alloyed Ti1-x-yAlxMeyN coatings (Me = W, Mo) with x asymptotic to 0.55 and y asymptotic to 0.10 during high-speed turning of stainless steel 316L. A difference in the crater wear rate was observed between TiAlN and Ti1-x-yAlxMeyN coatings. The wear behavior in the sliding area is characterized in detail for two different regions by scanning and transmission electron microscopy and energy dispersive X-ray spectroscopy. A thin adhered layer constituted of elements from the workpiece material is observed on the top of all coatings, followed by diffusion of species from the stainless steel 316L into the coatings. Co from the cemented carbide substrate also diffuses through column boundaries of the coating. The temperature varies in the sliding area. The presence of Mo or W retards the spinodal decomposition and the formation of h-AlN as compared to TiAlN coatings, leading to lower crater wear rate in alloyed coatings.

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  • 25.
    Nadhom, Hama
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Rouf, Polla
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Lundin, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Area Selective Deposition of Metals from the Electrical Resistivity of the Substrate2021Ingår i: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, The Journal of Physical Chemistry Letters, Vol. 12, nr 17, s. 4130-4133Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Area selective deposition (ASD) of films only on desired areas of the substrate opens for less complex fabrication of nanoscaled electronics. We show that a newly developed CVD method, where plasma electrons are used as the reducing agent in deposition of metallic thin films, is inherently area selective from the electrical resistivity of the substrate surface. When depositing iron with the new CVD method, no film is deposited on high-resistivity SiO2 surfaces whereas several hundred nanometers thick iron films are deposited on areas with low resistivity, obtained by adding a thin layer of silver on the SiO2 surface. On the basis of such a scheme, we show how to use the electric resistivity of the substrate surface as an extension of the ASD toolbox for metal-on-metal deposition.

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  • 26.
    Moreno, Maiara
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Andersson, Jon M.
    Seco Tools AB, Sweden.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. 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.
    Johnson, Lars J. S.
    Sandvik Coromant, Sweden.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Rogström, Lina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Crater wear mechanism of TiAlN coatings during high-speed metal turning2021Ingår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 484, artikel-id 204016Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The influence of the aluminium content (x) on crater wear mechanisms of Ti1-xAlxN coated WC-Co inserts in highspeed turning of 316L stainless steel was investigated. Electron microscopy and energy dispersive X-ray spectroscopy were used to characterize the wear behaviour. Ti1-xAlxN coatings with x &lt;= 0.53 showed, after 1/3 of the tool life, a thick adhered layer composed of oxides and metallic species from the steel, and no diffusion of workpiece material into the coating. These coatings presented the best wear resistance and least abrasive wear. The high aluminium content Ti0.38Al0.62N coating showed the worst crater wear resistance. This is assigned to interdiffusion of workpiece elements and oxygen into the coating as a consequence of spinodal decomposition of the cubic TiAlN-phase, resulting in more severe abrasive wear.

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  • 27.
    Calamba, Katherine
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Univ Lorraine, France; Sandvik Coromant AB, Sweden.
    Salamania, Janella
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Johansson, Mats P.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. SECO Tools AB, Sweden.
    Johnson, L. J. S.
    Sandvik Coromant AB, Sweden.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Pierson, J. F.
    Univ Lorraine, France.
    Sortica, M. A.
    Uppsala Univ, Sweden.
    Primetzhofer, D.
    Uppsala Univ, Sweden.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Effect of nitrogen vacancies on the growth, dislocation structure, and decomposition of single crystal epitaxial (Ti1-xAlx)N-y thin films2021Ingår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 203, artikel-id 116509Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of varying nitrogen vacancies on the growth, microstructure, spinodal decomposition and hardness values of predominantly single crystal cubic phase c-(Ti1-xAlx)N-y films was investigated. Epitaxial c-(Ti1-xAlx)N-y films with y = 0.67, 0.79, and 0.92 were grown on MgO(001) and MgO(111) substrates by magnetron sputter deposition. High N vacancy c-(Ti1-xAlx)N-0.67 films deposited on MgO(111) contained coherently oriented w-(0001) structures while segregated conical structures were observed on the films grown on MgO(001). High resolution STEM images revealed that the N-deficient growth conditions induced segregation with small compositional fluctuations that increase with the number of N vacancies. Similarly, strain map analysis of the epitaxial c-(Ti1-xAlx)N-y (001) and (111) films show fluctuations in strain concentration that scales with the number of N vacancies and increases during annealing. The spinodal decomposition coarsening rate of the epitaxial c-(Ti1-xAlx)N-y films was observed to increase with decreasing N vacancies. Nanoindentation showed decreasing trends in hardness of the as-deposited films as the N vacancies increase. Isothermal post-anneal at 1100 degrees C in vacuum for 120 min revealed a continuation in the increase in hardness for the film with the largest number of N vacancies (y = 0.67) while the hardness decreased for the films with y = 0.79 and 0.92. These results suggest that nitrogen-deficient depositions of c-(Ti1-xAlx)N-y films help to promote a self-organized phase segregation, while higher N vacancies generally increase the coherency strain which delays the coarsening process and can influence the hardness at high temperatures. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd.

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  • 28.
    Salamania, Janella
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Johnson, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Sandvik Coromant, Sweden.
    Schramm, I. C.
    Sandvik Coromant, Sweden.
    Calamba, K. M.
    Sandvik Coromant, Sweden.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Bakhit, Babak
    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.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Influence of pulsed-substrate bias duty cycle on the microstructure and defects of cathodic arc-deposited Ti1-xAlxN coatings2021Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 419, artikel-id 127295Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The influence of pulsed substrate bias duty cycle on the growth, microstructure, and defects of Ti1-xAlxN coatings grown by cathodic arc deposition was investigated. Ti1-xAlxN coatings of varying compositions (x = 0.56, 0.38, 0.23) were deposited on cemented carbide substrates with 10, 25, 50, and 95% duty cycles of 50 V pulsed-bias under 10 Pa of pure N-2 gas. Coatings grown at low duty cycles (10 and 25%) showed strongly textured, underdense coatings with facetted columns and low amount of lattice defects. Applying higher duty cycles (50 and 95%) produced coatings that have denser microstructures, less preferred orientation, increasing compressive stresses and increased lattice defect densities. Our study elucidates how duty cycle variation not only changes the overall average energy supplied at the growth front but also kinetically influences the coating growth and thus microstructure and defect structure.

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  • 29.
    Hsu, Tun-Wei
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Kolozsvári, Szilárd
    PLANSEE Composite Materials GmbH, Germany.
    Polcik, Peter
    PLANSEE Composite Materials GmbH, Germany.
    Bolz, Stephan
    CemeCon AG, Germany.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Influence of Si content on phase stability and mechanical properties of TiAlSiN films grown by AlSi-HiPIMS/Ti-DCMS co-sputtering2021Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 427, artikel-id 127661Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ti1-x(AlySi1-y)xN coatings covering a wide compositional range, 0.38 < x < 0.76 and 0.68 ≤ y ≤ 1.00, are deposited to investigate the influence of Al+/Si+ ion irradiation on microstructural and mechanical properties. The samples are grown in Ar/N2 atmosphere by the hybrid high-power impulse and dc magnetron co-sputtering (HiPIMS/DCMS) method with substrate bias synchronized to the Al+/Si+-rich portion of the HiPIMS pulses. Two Ti targets are operated in DCMS mode, while one AlSi target is operated in HiPIMS mode. Four different AlSi target compositions are used: Al1.0Si0.0, Al0.9Si0.1, Al0.8Si0.2, and Al0.6Si0.4. X-ray diffractometry reveals that films without Si (i.e., y = 1.0) have high Al solubility in NaCl-structure, c-TiAlN, up to x ≤ 0.67 no w-AlN is detected. Once Si (y < 1.0) is introduced the Al solubility limit decreases, but remains higher than other PVD techniques, along with grain refinement and the formation of a SiNz rich tissues phase, as shown by transmission electron microscopy. The nanoindentation hardness is high (~ 30 GPa) for all films that do not contain the w-AlN phase. All the coatings have compressive stresses lower than -3 GPa. Interestingly, a range of films with different compositions displayed both high hardness (~ 30 GPa) and low residual stress (σ < 0.5 GPa). Such an unique combination of properties highlights the benefits of using HiPIMS/DCMS configuration with metal-ion-synchronized substrate bias, which utilizes the Al+/Si+ supplantation effect and minimizes the Ar+ incorporation.

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  • 30.
    Shimizu, Tetsuhide
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten. Tokyo Metropolitan Univ, Japan.
    Takahashi, Kazuki
    Tokyo Metropolitan Univ, Japan.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Viloan, Rommel Paulo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Keraudy, Julien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Lundin, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Yang, Ming
    Tokyo Metropolitan Univ, Japan.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Low temperature growth of stress-free single phase alpha-W films using HiPIMS with synchronized pulsed substrate bias2021Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 129, nr 15, artikel-id 155305Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Efficient metal-ion-irradiation during film growth with the concurrent reduction of gas-ion-irradiation is realized for high power impulse magnetron sputtering by the use of a synchronized, but delayed, pulsed substrate bias. In this way, the growth of stress-free, single phase alpha -W thin films is demonstrated without additional substrate heating or post-annealing. By synchronizing the pulsed substrate bias to the metal-ion rich portion of the discharge, tungsten films with a 110 oriented crystal texture are obtained as compared to the 111 orientation obtained using a continuous substrate bias. At the same time, a reduction of Ar incorporation in the films are observed, resulting in the decrease of compressive film stress from sigma =1.80-1.43GPa when switching from continuous to synchronized bias. This trend is further enhanced by the increase of the synchronized bias voltage, whereby a much lower compressive stress sigma =0.71GPa is obtained at U-s=200V. In addition, switching the inert gas from Ar to Kr has led to fully relaxed, low tensile stress (0.03GPa) tungsten films with no measurable concentration of trapped gas atoms. Room-temperature electrical resistivity is correlated with the microstructural properties, showing lower resistivities for higher U-s and having the lowest resistivity (14.2 mu Omega cm) for the Kr sputtered tungsten films. These results illustrate the clear benefit of utilizing selective metal-ion-irradiation during film growth as an effective pathway to minimize the compressive stress induced by high-energetic gas ions/neutrals during low temperature growth of high melting temperature materials.

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  • 31.
    Ekeroth, Sebastian
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Ekspong, Joakim
    Umea Univ, Sweden.
    Perivoliotis, Dimitrios K.
    Umea Univ, Sweden.
    Sharma, Sachin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Brenning, Nils
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten. KTH Royal Inst Technol, Sweden.
    Gracia-Espino, Eduardo
    Umea Univ, Sweden.
    Edman, Ludvig
    Umea Univ, Sweden.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Wagberg, Thomas
    Umea Univ, Sweden.
    Magnetically Collected Platinum/Nickel Alloy Nanoparticles as Catalysts for Hydrogen Evolution2021Ingår i: ACS Applied Nano Materials, E-ISSN 2574-0970, Vol. 4, nr 12, s. 12957-12965Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The hydrogen evolution reaction (HER) is a key process in electrochemical water splitting. To lower the cost and environmental impact of this process, it is highly motivated to develop electrocatalysts with low or no content of noble metals. Here, we report on an ingenious synthesis of hybrid PtxNi1-x electrocatalysts in the form of a nanoparticle-nanonetwork structure with very low noble metal content. The structure possesses important features such as good electrical conductivity, high surface area, strong interlinking, and substrate adhesion, which render an excellent HER activity. Specifically, the best performing Pt0.05Ni0.95 sample demonstrates a Tafel slope of 30 mV dec-1 in 0.5 M H2SO4 and an overpotential of 20 mV at a current density of 10 mA cm-2 with high stability. The impressive catalytic performance is further rationalized in a theoretical study, which provides insight into the mechanism on how such small platinum content can allow for close-to-optimal adsorption energies for hydrogen.

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  • 32.
    Gangaprasad Rao, Smita
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Shu, Rui
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Le Febvrier, Arnaud
    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.
    Phase formation and structural evolution of multicomponent (CrFeCo)Ny films2021Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 412, artikel-id 127059Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Cantor alloy (CoCrFeMnNi) and its variants, in bulk as well as thin films, have been extensively studied. They are known to exhibit cubic crystal structures and thermodynamic stability regardless of their complex chemical composition. Therefore, they may find use as hard, wear-resistant, corrosion and oxidation-resistant coatings. The addition of light elements, such as nitrogen, is known to help improve these properties further through processes such as amorphization and nitride compound formation. Here, we investigate the ternary CrFeCo system to study the effects of nitrogen addition. (CrFeCo)Ny multicomponent thin films are grown on silicon substrates by DC magnetron sputtering. Changes in crystal structure, morphology, mechanical and electrical properties with gradual increases of nitrogen in the film are described and discussed. Increased addition of nitrogen from 14 at.% to 28 at.% in the film leads to a transformation from an fcc to a bcc crystal structure, affects both the mechanical and electrical properties. XPS analysis shows the tendency of nitrogen to bond with Cr over other metals. The films display hardness values between 7 and 11 GPa with resistivities values ranging between 28 and 165 μΩ cm.

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  • 33.
    Shu, Rui
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Paschalidou, Eirini-Maria
    Department of Chemistry-Ångström, Uppsala University.
    Gangaprasad Rao, Smita
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Moro, Marcos Vinicius
    Department of Physics and Astronomy, Uppsala University.
    Primetzhofer, Daniel
    Department of Physics and Astronomy, Uppsala University.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Nyholm, Leif
    Department of Chemistry-Ångström, Uppsala University.
    Le Febvrier, Arnaud
    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.
    Effect of nitrogen content on microstructure and corrosion resistance of sputter-deposited multicomponent (TiNbZrTa)Nx films2020Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 404, artikel-id 126485Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multicomponent (TiNbZrTa)Nx films were deposited on Si(100) substrates at room temperature using magnetron sputtering with a nitrogen flow ratio fN [fN = N2/(Ar + N2)], which was varied from 0 to 30.8%. The nitrogen content in the films varied between 0 and 45.2 at.%, i.e., x = 0 to 0.83. The microstructure was characterized by X-ray diffraction and electron microscopy. The metallic TiNbZrTa film comprised a dominant bcc solid-solution phase, whereas a single NaCl-type face-centred cubic structure was observed in all nitrogen-containing films (TiNbZrTa)Nx. The mechanical, electrical, and electrochemical properties of these films varied with nitrogen content. The maximum hardness was achieved at 22.1 ± 0.3 GPa when N = 43.0 at.%. The resistivities increased from 95 to 424 μΩcm with increasing nitrogen content. A detailed study of the variation of morphology and chemical bonding with nitrogen content was performed and the corrosion resistance of the TiNbZrTa nitride films was explored in 0.1 M H2SO4. While all the films had excellent corrosion resistances at potentials up to 2.0 V vs. Ag/AgCl, the metallic film and the films with low nitrogen contents (x < 0.60) exhibited an almost stable current plateau up to 4.0 V vs. Ag/AgCl. For the films with higher nitrogen contents (x ≥ 0.68), the current plateau was retained up to 2.0 V vs. Ag/AgCl, above which a higher nitrogen content resulted in a higher current. The decrease in the corrosion resistance at these high potentials indicate the presence of a potential-dependent activation effect resulting in an increased oxidation rate of the nitrides (present under the passive oxide film) yielding a release of nitrogen from the films. TEM results indicate that the oxide layer formed after this corrosion measurement was thick and porous for the film with x = 0.76, in very good agreement with the increased corrosion rate for this film. The results demonstrate that an increased nitrogen content in (TiNbZrTa)Nx system improves their mechanical properties with retained high corrosion resistance at potentials up to 2.0 V vs. Ag/AgCl in 0.1 M H2SO4. At even higher potentials, however, the corrosion resistance decreases with increasing nitrogen concentration for films with sufficiently high nitrogen contents (i.e. x ≥ 0.68).

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  • 34.
    Xu, Jinghao
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Konstruktionsmaterial. Linköpings universitet, Tekniska fakulteten.
    Gruber, Hans
    Chalmers University of Technology, Gothenburg, Sweden.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och ytbeläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Jiang, Shuang
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Konstruktionsmaterial. Linköpings universitet, Tekniska fakulteten.
    Peng, Ru Lin
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Konstruktionsmaterial. Linköpings universitet, Tekniska fakulteten.
    Moverare, Johan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Konstruktionsmaterial. Linköpings universitet, Tekniska fakulteten.
    On the Strengthening and Embrittlement Mechanisms of an Additively Manufactured Nickel-base Superalloy2020Ingår i: Materialia, Vol. 10, artikel-id 100657Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The γ′ phase strengthened Nickel-base superalloy is one of the most significant dual-phase alloy systems for high-temperature engineering applications. The tensile properties of laser powder-bed-fused IN738LC superalloy in the as-built state have been shown to have both good strength and ductility compared with its post-thermal treated state. A microstructural hierarchy composed of weak texture, sub-micron cellular structures and dislocation cellular walls was promoted in the as-built sample. After post-thermal treatment, the secondary phase γ′ precipitated with various size and fraction depending on heat treatment process. For room-temperature tensile tests, the dominated deformation mechanism is planar slip of dislocations in the as-built sample while dislocations bypassing the precipitates via Orowan looping in the γ′ strengthened samples. The extraordinary strengthening effect due to the dislocation substructure in the as-built sample provides an addition of 372 MPa in yield strength. The results of our calculation are in agreement with experimental yield strength for all the three different conditions investigated. Strikingly, the γ′ strengthened samples have higher work hardening rate than as-built sample but encounter premature failure. Experimental evidence shows that the embrittlement mechanism in the γ′ strengthened samples is caused by the high dislocation hardening of the grain interior region, which reduces the ability to accommodate further plastic strain and leads to premature intergranular cracking. On the basis of these results, the strengthening micromechanism and double-edge effect of strength and ductility of Nickel-base superalloy is discussed in detail.

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  • 35.
    Viloan, Rommel Paulo B.
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Gu, Jiabin
    School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, PR China.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Keraudy, Julien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Li, Liuhe
    School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, PR China.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Bipolar high power impulse magnetron sputtering for energetic ion bombardment during TiN thin film growth without the use of a substrate bias2019Ingår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 688, artikel-id 137350Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of applying a positive voltage pulse (Urev = 10–150 V) directly after the negative high power impulse magnetron sputtering (HiPIMS) pulse (bipolar HiPIMS) is investigated for the reactive sputter deposition of TiN thin films. Energy-resolved mass spectroscopy analyses are performed to gain insight in the effect on the ion energy distribution function of the various ions. It is demonstrated that the energy of a large fraction of the ions can be tuned by a reverse target potential and gain energy corresponding to the applied Urev. Microscopy observations and x-ray reflectometry reveal densification of the films which results in an increase in the film hardness from 23.9 to 34 GPa as well as an increase in compressive film stress from 2.1 GPa to 4.7 GPa when comparing conventional HiPIMS with bipolar HiPIMS (Urev = 150 V).

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    Bipolar high power impulse magnetron sputtering for energetic ion bombardment during TiN thin film growth without the use of a substrate bias
  • 36.
    Calamba, Katherine
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Univ Lorraine, France.
    Pierson, J. F.
    Univ Lorraine, France.
    Bruyere, S.
    Univ Lorraine, France.
    Le Febvrier, Arnaud
    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.
    Barrirero, Jenifer
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Saarland Univ, Germany.
    Muecklich, F.
    Saarland Univ, Germany.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Jöesaar Johansson, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. SECO Tools AB, Sweden.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Dislocation structure and microstrain evolution during spinodal decomposition of reactive magnetron sputtered heteroepixatial c-(Ti-0.37,Al-0.63)N/c-TiN films grown on MgO(001) and (111) substrates2019Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 125, nr 10, artikel-id 105301Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Heteroepitaxial c-(Ti-0.37,Al-0.63)N thin films were grown on MgO(001) and MgO(111) substrates using reactive magnetron sputtering. High resolution high-angle annular dark-field scanning transmission electron micrographs show coherency between the film and the substrate. In the as-deposited state, x-ray diffraction reciprocal space maps show a strained epitaxial film. Corresponding geometric phase analysis (GPA) deformation maps show a high stress in the film. At elevated temperature (900 degrees C), the films decompose to form iso-structural coherent c-Al- and c-TiN-rich domains, elongated along the elastically soft amp;lt;100amp;gt; directions. GPA analysis reveals that the c-TiN domains accommodate more dislocations than the c-AlN domains. This is because of the stronger directionality of the covalent bonds in c-AlN compared with c-TiN, making it more favorable for the dislocations to accumulate in c-TiN. The defect structure and strain generation in c-(Ti,Al)N during spinodal decomposition is affected by the chemical bonding state and elastic properties of the segregated domains.

  • 37.
    Calamba, Katherine
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Univ Lorraine, France.
    Barrirero, Jenifer
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Saarland Univ, Germany.
    Joesaar, M. P. Johansson
    SECO Tools AB, Sweden.
    Bruyere, S.
    Univ Lorraine, France.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Pierson, J. F.
    Univ Lorraine, France.
    Le Febvrier, Arnaud
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Muecklich, F.
    Saarland Univ, Germany.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Growth and high temperature decomposition of epitaxial metastable wurtzite (Ti1-x,Al-x)N(0001) thin films2019Ingår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 688, artikel-id 137414Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The structure, growth, and phase stability of (Ti1-x,Al-x)N films with high Al content were investigated. (Ti1-x,Al-x)N (x= 0.63 and 0.77) thin films were grown on MgO (111) substrates at 700 degrees C using a UHV DC magnetron sputtering system. The (Ti-0.37,Al-0.63)N film is a single crystal with a cubic NaCl (B1) structure while the (T-i0.23,Al-0.77)N film only shows epitaxial growth of the same cubic phase in the first few atomic layers. With increasing film thickness, epitaxial wurtzite (B4) forms. The thin cubic layer and the wurtzite film has an orientation relationship of c-(Ti-0.23,Al-0.77)N(111)[110]parallel to w-(Ti-0.23,Al-0.77)N(0001)[11 (2) over bar0]. Continued deposition results in a gradual break-down of the epitaxial growth. It is replaced by polycrystalline growth of wurtzite columns with a high degree of 0001 texture, separated by a Tienriched cubic phase. In the as-deposited state, c-(Ti-0.27,Al-0.63)N displays a homogeneous chemical distribution while the w-(Ti-0.23,Al-0.77)N has segregated to Al- and Ti-rich domains. Annealing at 900 degrees C resulted in the spinodal decomposition of the metastable c-(Ti-0.27,Al-0.63)N film and formation of coherent elongated c-AlN and cTi-N-rich domains with an average width of 4.5 +/- 0.2 nm while the width of the domains in the w-(Ti-0.23,Al-0.77)N film only marginally increases to 2.8 +/- 0.1 nm. The slower coarsening rate of the wurtzite structure compared to cubic is indicative of a higher thermal stability.

  • 38.
    Ekeroth, Sebastian
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Ikeda, Shuga
    Tokyo Metropolitan Univ, Japan.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Shimizu, Tetsuhide
    Tokyo Metropolitan Univ, Japan.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Growth of semi-coherent Ni and NiO dual-phase nanoparticles using hollow cathode sputtering2019Ingår i: Journal of nanoparticle research, ISSN 1388-0764, E-ISSN 1572-896X, Vol. 21, nr 2, artikel-id 37Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Anisotropic heterogenous Ni/NiO nanoparticles with controlled compositions are grown using a high-power pulsed hollow cathode process. These novel particles can be tuned to consist of single-phase Ni via two-phase Ni/NiO to fully oxidized NiO, with a size range of 5-25 nm for individual crystals. A novelty of this approach is the ability to assemble multiple particles of Ni and NiO into a single complex structure, increasing the Ni-NiO interface density. This type of particle growth is not seen before and is explained to be due to the fact that the process operates in a single-step approach, where both Ni and O can arrive at the formed nanoparticle nuclei and aid in the continuous particle growth. The finished particle will then be a consequence of the initially formed crystal, as well as the arrival rate ratio of the two species. These particles hold great potential for applications in fields, such as electro- and photocatalysis, where the ability to control the level of oxidation and/or interface density is of great importance.

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  • 39.
    Ekeroth, Sebastian
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Ikeda, Shuga
    Department of Intelligent Mechanical Systems, Tokyo Metropolitan University, Tokyo, Japan.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Münger, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Shimizu, Tetsuhide
    Department of Intelligent Mechanical Systems, Tokyo Metropolitan University, Tokyo, Japan.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Impact of nanoparticle magnetization on the 3D formation of dual-phase Ni/NiO nanoparticle-based nanotrusses2019Ingår i: Journal of nanoparticle research, ISSN 1388-0764, E-ISSN 1572-896X, Vol. 21, nr 11, artikel-id 21:228Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Magnetic nanoparticles with average size 30 nm were utilized to build three-dimensional framework structures—nanotrusses. In dual-phase Ni/NiO nanoparticles, there is a strong correlation between the amount of magnetic Ni and the final size and shape of the nanotruss. As it decreases, the length of the individual nanowires within the trusses also decreases, caused by a higher degree of branching of the wires. The position and orientation of the non-magnetic material within the truss structure was also investigated for the different phase compositions. For lower concentrations of NiO phase, the electrically conducting Ni-wire framework is maintained through the preferential bonding between the Ni crystals. For larger concentrations of NiO phase, the Ni-wire framework is interrupted by the NiO. The ability to use nanoparticles that are only partly oxidized in the growth of nanotruss structures is of great importance. It opens the possibility for using not only magnetic metals such as pure Ni, Fe, and Co, but also to use dual-phase nanoparticles that can strongly increase the efficiency of e.g. catalytic electrodes and fuel cells.

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  • 40.
    Calamba, Katherine
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Univ Lorraine, France.
    Jöesaar Johansson, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. SECO Tools AB, Sweden.
    Bruyere, S.
    Univ Lorraine, France.
    Pierson, J. F.
    Univ Lorraine, France.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Andersson, J. M.
    SECO Tools AB, Sweden.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    The effect of nitrogen vacancies on initial wear in arc deposited (Ti-0.52,Ti- Al-0.48)N-y, (y < 1) coatings during machining2019Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 358, s. 452-460Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nitrogen deficient c-(Ti0.52Al0.48)Ny, y = 0.92, y = 0.87, and y = 0.75 coatings were prepared in different N-2/Ar discharges on WC-Co inserts by reactive cathodic arc deposition. The microstructure of the y = 0.92 coating show that spinodal decomposition has occurred resulting in the formation of coherent c-TiN- and c-AIN rich domains during cutting. The y = 0.87 and y = 0.75 coatings have exhibited a delay in decomposition due to the presence of nitrogen vacancies that lowers the free energy of the system. In the decomposed structure, grain boundaries and misfit dislocations enhance the diffusion of elements from the workpiece and the substrate (e.g. Fe, Cr, and Co) into the coatings and it becomes more susceptible to crater wear. The y = 0.87 sample displays the highest crater wear resistance because of its dense grain boundaries that prevent chemical wear. The y = 0.92 sample has the best flank wear resistance because the decomposition results in age hardening. The y = 0.75 sample contains the MAX-phase Ti(2)AIN after cutting. The chemical alteration within the y = 0.75 sample and its high amount of macroparticles cause its low wear resistance. The different microstructure evolution caused by different amount of N-vacancies result in distinctive interactions between chip and coating, which also causes difference in the initial wear mechanism of the (Ti,Al)/N-y coatings.

  • 41.
    Ekeroth, Sebastian
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Münger, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Ekspong, Joakim
    Umeå Univ, Sweden.
    Wågberg, Thomas
    Umeå Univ, Sweden.
    Edman, Ludvig
    Umeå Univ, Sweden.
    Brenning, Nils
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten. KTH Royal Inst Technol, Sweden.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Catalytic Nanotruss Structures Realized by Magnetic Self-Assembly in Pulsed Plasma2018Ingår i: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 18, nr 5, s. 3132-3137Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Tunable nanostructures that feature a high surface area are firmly attached to a conducting substrate and can be fabricated efficiently over significant areas, which are of interest for a wide variety of applications in, for instance, energy storage and catalysis. We present a novel approach to fabricate Fe nanoparticles using a pulsed-plasma process and their subsequent guidance and self-organization into well-defined nanostructures on a substrate of choice by the use of an external magnetic field. A systematic analysis and study of the growth procedure demonstrate that nondesired nanoparticle agglomeration in the plasma phase is hindered by electrostatic repulsion, that a polydisperse nanoparticle distribution is a consequence of the magnetic collection, and that the formation of highly networked nanotruss structures is a direct result of the polydisperse nanoparticle distribution. The nanoparticles in the nanotruss are strongly connected, and their outer surfaces are covered with a 2 nm layer of iron oxide. A 10 mu m thick nanotruss structure was grown on a lightweight, flexible and conducting carbon-paper substrate, which enabled the efficient production of H-2 gas from water splitting at a low overpotential of 210 mV and at a current density of 10 mA/cm(2).

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  • 42.
    Eriksson, Peter
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Tal, Alexey
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Skallberg, Andreas
    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 fakulteten.
    Hu, Zhang-Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Olovsson, Weine
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Fairley, Neal
    Casa Software Ltd, Bay House, Teignmouth, United Kingdom.
    Abrikosov, Igor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten. Materials Modeling and Development Laboratory, National University of Science and Technology “MISIS”, Moscow, Russia.
    Zhang, Xuanjun
    Faculty of Health Sciences, University of Macau, Macau, SAR, China.
    Uvdal, Kajsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Cerium oxide nanoparticles with antioxidant capabilities and gadolinium integration for MRI contrast enhancement2018Ingår i: Scientific Reports, E-ISSN 2045-2322, Vol. 8, artikel-id 6999Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The chelating gadolinium-complex is routinely used as magnetic resonance imaging (MRI) -contrast enhancer. However, several safety issues have recently been reported by FDA and PRAC. There is an urgent need for the next generation of safer MRI-contrast enhancers, with improved local contrast and targeting capabilities. Cerium oxide nanoparticles (CeNPs) are designed with fractions of up to 50% gadolinium to utilize the superior MRI-contrast properties of gadolinium. CeNPs are well-tolerated in vivo and have redox properties making them suitable for biomedical applications, for example scavenging purposes on the tissue-and cellular level and during tumor treatment to reduce in vivo inflammatory processes. Our near edge X-ray absorption fine structure (NEXAFS) studies show that implementation of gadolinium changes the initial co-existence of oxidation states Ce3+ and Ce4+ of cerium, thereby affecting the scavenging properties of the nanoparticles. Based on ab initio electronic structure calculations, we describe the most prominent spectral features for the respective oxidation states. The as-prepared gadolinium-implemented CeNPs are 3-5 nm in size, have r(1)-relaxivities between 7-13 mM(-1) s(-1) and show clear antioxidative properties, all of which means they are promising theranostic agents for use in future biomedical applications.

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  • 43.
    Villamayor, Michelle M
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten. Uppsala Univ, Sweden.
    Keraudy, Julien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten. Oerlikon Balzers, Liechtenstein.
    Shimizu, Tetsuhide
    Tokyo Metropolitan Univ, Japan.
    Viloan, Rommel Paulo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Lundin, Daniel
    Univ Paris Saclay, France.
    Greene, Joseph E
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Low temperature (T-s/T-m < 0.1) epitaxial growth of HfN/MgO(001) via reactive HiPIMS with metal-ion synchronized substrate bias2018Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 36, nr 6, artikel-id 061511Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Low-temperature epitaxial growth of refractory transition-metal nitride thin films by means of physical vapor deposition has been a recurring theme in advanced thin-film technology for several years. In the present study, 150-nm-thick epitaxial HfN layers are grown on MgO(001) by reactive high-power impulse magnetron sputtering (HiPIMS) with no external substrate heating. Maximum film-growth temperatures T-s due to plasma heating range from 70 to 150 degrees C, corresponding to T-s/T-m = 0.10-0.12 (in which T-m is the HfN melting point in K). During HiPIMS, gas and sputtered metal-ion fluxes incident at the growing film surface are separated in time due to strong gas rarefaction and the transition to a metal-ion-dominated plasma. In the present experiments, a negative bias of 100 V is applied to the substrate, either continuously during the entire deposition or synchronized with the metal-rich portion of the ion flux. Two different sputtering-gas mixtures, Ar/N-2 and Kr/N-2, are employed in order to probe effects associated with the noble-gas mass and ionization potential. The combination of x-ray diffraction, high-resolution reciprocal-lattice maps, and high-resolution cross-sectional transmission electron microscopy analyses establishes that all HfN films have a cube-on-cube orientational relationship with the substrate, i.e., [001](HfN)parallel to[001](MgO) and (100)(HfN)parallel to(100)(MgO). Layers grown with a continuous substrate bias, in either Ar/N-2 or Kr/N-2, exhibit a relatively high mosaicity and a high concentration of trapped inert gas. In distinct contrast, layers grown in Kr/N-2 with the substrate bias synchronized to the metal-ion-rich portion of HiPIMS pulses have much lower mosaicity, no measurable inert-gas incorporation, and a hardness of 25.7 GPa, in good agreement with the results for epitaxial HfN(001) layers grown at T-s = 650 degrees C (T-s/T-m = 0.26). The room-temperature film resistivity is 70 mu Omega cm, which is 3.2-10 times lower than reported values for polycrystalline-HfN layers grown at T-s = 400 degrees C. (c) 2018 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

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  • 44.
    Gunnarsson, Rickard
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Brenning, Nils
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten. KTH Royal Inst Technol, Sweden.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Nucleation of titanium nanoparticles in an oxygen-starved environment. I: experiments2018Ingår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 51, nr 45, artikel-id 455201Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A constant supply of oxygen has been assumed to be necessary for the growth of titanium nanoparticles by sputtering. This oxygen supply can arise from a high background pressure in the vacuum system or from a purposely supplied gas. The supply of oxygen makes it difficult to grow metallic nanoparticles of titanium and can cause process problems by reacting with the target. We here report that growth of titanium nanoparticles in the metallic hexagonal titanium (alpha Ti) phase is possible using a pulsed hollow cathode sputter plasma and adding a high partial pressure of helium to the process instead of trace amounts of oxygen. The helium cools the process gas in which the nanoparticles nucleate. This is important both for the first dimer formation and the continued growth to a thermodynamically stable size. The parameter region, inside which the synthesis of nanoparticles is possible, is mapped out experimentally and the theory of the physical processes behind this process window is outlined. A pressure limit below which no nanoparticles were produced was found at 200 Pa, and could be attributed to a low dimer formation rate, mainly caused by a more rapid dilution of the growth material. Nanoparticle production also disappeared at argon gas flows above 25 sccm. In this case, the main reason was identified as a gas temperature increase within the nucleation zone, giving a too high evaporation rate from nanoparticles (clusters) in the stage of growth from dimers to stable nuclei. These two mechanisms are in depth explored in a companion paper. A process stability limit was also found at low argon gas partial pressures, and could be attributed to a transition from a hollow cathode discharge to a glow discharge.

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  • 45.
    Keraudy, Julien
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Shimizu, Tetsuhide
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten. Tokyo Metropolitan Univ, Japan.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Jouan, P-Y
    Univ Nantes, France.
    Phase separation within NiSiN coatings during reactive HiPIMS discharges: A new pathway to grow NixSi nanocrystals composites at low temperature2018Ingår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 454, s. 148-156Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The precise control of the growth nanostructured thin films at low temperature is critical for the continued development of microelectronic enabled devices. In this study, nanocomposite Ni-Si-N thin films were deposited at low temperature by reactive high-power impulse magnetron sputtering. A composite Ni-Si target (15 at.% Si) in combination with a Ar/N-2 plasma were used to deposit films onto Si(0 01) substrates, without any additional substrate heating or any post-annealing. The films microstructure changes from a polycrystalline to nanocomposite structure when the nitrogen content exceeds 16 at.%. X-ray diffraction and (scanning) transmission electron microscopy analyses reveal that the microstructure consists of nanocrystals, NixSi (x amp;gt; 1) 7-8 nm in size, embedded in an amorphous SiN x matrix. It is proposed that this nanostructure is formed at low temperatures due to the repeated-nucleation of NixSi nanocrystals, the growth of which is restricted by the formation of the SiNx phase. X-ray photoelectron spectroscopy revealed the trace presence of a ternary solid solution mainly induced by the diffusion of Ni into the SiNx matrix. Four-probe electrical measurements reveal all the deposited films are electrically conducing.

  • 46.
    Elofsson, Viktor
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanodesign. Linköpings universitet, Tekniska fakulteten.
    Almyras, Georgios
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanodesign. Linköpings universitet, Tekniska fakulteten.
    Lü, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanodesign. Linköpings universitet, Tekniska fakulteten.
    Garbrecht, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Sarakinos, Kostas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanodesign. Linköpings universitet, Tekniska fakulteten.
    Structure formation in Ag-X (X = Au, Cu) alloys synthesized far-from-equilibrium2018Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 123, nr 16Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We employ sub-monolayer, pulsed Ag and Au vapor fluxes, along with deterministic growth simulations, and nanoscale probes to study structure formation in miscible Ag-Au films synthesized under far-from-equilibrium conditions. Our results show that nanoscale atomic arrangement is primarily determined by roughness build up at the film growth front, whereby larger roughness leads to increased intermixing between Ag and Au. These findings suggest a different structure formation pathway as compared to the immiscible Ag-Cu system for which the present study, in combination with previously published data, reveals that no significant roughness is developed, and the local atomic structure is predominantly determined by the tendency of Ag and Cu to phase-separate.

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  • 47.
    Magnfält, Daniel
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanodesign. Linköpings universitet, Tekniska fakulteten.
    Melander, E.
    Uppsala University, Sweden.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Kapaklis, V.
    Uppsala University, Sweden.
    Sarakinos, Kostas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanodesign. Linköpings universitet, Tekniska fakulteten.
    Synthesis of tunable plasmonic metal-ceramic nanocomposite thin films by temporally modulated sputtered fluxes2017Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 121, nr 17, artikel-id 171918Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The scientific and technological interest for metal-dielectric nanocomposite thin films emanates from the excitation of localized surface plasmon resonances (LSPRs) on the metal component. The overall optical response of the nanocomposite is governed by the refractive index of the dielectric matrix and the properties of the metallic nanoparticles in terms of their bulk optical properties, size, and shape, and the inter-particle distance of separation. In order to tune the film morphology and optical properties, complex synthesis processes which include multiple steps-i. e., film deposition followed by post-deposition treatment by thermal or laser annealing-are commonly employed. In the present study, we demonstrate that the absorption resonances of Ag/AlOxNy nanocomposite films can be effectively tuned from green (similar to 2.4 eV) to violet (similar to 2.8 eV) using a single-step synthesis process that is based on modulating the arrival pattern of film forming species with sub-monolayer resolution, while keeping the amount of Ag in the films constant. Our data indicate that the optical response of the films is the result of LSPRs on isolated Ag nanoparticles that are seemingly shifted by dipolar interactions between neighboring particles. The synthesis strategy presented may be of relevance for enabling integration of plasmonic nanocomposite films on thermally sensitive substrates. Published by AIP Publishing.

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  • 48.
    Elofsson, Viktor
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanodesign. Linköpings universitet, Tekniska fakulteten.
    Almyras, Georgios
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanodesign. Linköpings universitet, Tekniska fakulteten.
    Lu, B.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanodesign. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Sarakinos, Kostas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanodesign. Linköpings universitet, Tekniska fakulteten.
    Atomic arrangement in immiscible Ag-Cu alloys synthesized far-from-equilibrium2016Ingår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 110, s. 114-121Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Physical attributes of multicomponent materials of a given chemical composition are determined by atomic arrangement at property-relevant length scales. A potential route to access a vast array of atomic configurations for material property tuning is by synthesis of multicomponent thin films using vapor fluxes with their deposition pattern modulated in the sub-monolayer regime. However, the applicability of this route for creating new functional materials is impeded by the fact that a fundamental understanding of the combined effect of sub-monolayer flux modulation, kinetics and thermodynamics on atomic arrangement is not available in the literature. Here we present a research strategy and verify its viability for addressing the aforementioned gap in knowledge. This strategy encompasses thin film synthesis using a route that generates multi-atomic fluxes with sub-monolayer resolution and precision over a wide range of experimental conditions, deterministic growth simulations and nanoscale micro structural probes. Investigations are focused on structure formation within the archetype immiscible Ag-Cu binary system, revealing that atomic arrangement at different length scales is governed by the arrival pattern of the film forming species, in conjunction with diffusion of near-surface Ag atoms to encapsulate 3D Cu islands growing on 2D Ag layers. The knowledge generated and the methodology presented herein provides the scientific foundation for tailoring atomic arrangement and physical properties in a wide range of miscible and immiscible multinary systems. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  • 49.
    Boyd, Robert
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Söderlind, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Pilch, Iris
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Complex 3D nanocoral like structures formed by copper nanoparticle aggregation on nanostructured zinc oxide rods2016Ingår i: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 184, s. 127-130Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper reports a new strategy for nanoparticle surface assembly so that they form anisotropic fibril like features, consisting of particles directly attached to each other, which can extend 500 nm from the surface. The particles are both formed and deposited in a single step process enabled via the use of a pulsed plasma based technique. Using this approach, we have successfully modified zinc oxide rods, up to several hundred nanometers in diameter, with 25 nm diameter copper nanoparticles for catalytic applications. The resulting structure could be modelled using a diffusion limited aggregation based approach. This gives the material the appearance of marine coral, hence the term nanocoral. (C) 2016 Elsevier B.V. All rights reserved.

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  • 50.
    Magnfält, Daniel
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten.
    Fillon, A.
    University of Poitiers, France; INSA Rennes, France.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Sarakinos, Kostas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanodesign. Linköpings universitet, Tekniska fakulteten.
    Abadias, G.
    University of Poitiers, France.
    Compressive intrinsic stress originates in the grain boundaries of dense refractory polycrystalline thin films2016Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 119, nr 5, s. 055305-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Intrinsic stresses in vapor deposited thin films have been a topic of considerable scientific and technological interest owing to their importance for functionality and performance of thin film devices. The origin of compressive stresses typically observed during deposition of polycrystalline metal films at conditions that result in high atomic mobility has been under debate in the literature in the course of the past decades. In this study, we contribute towards resolving this debate by investigating the grain size dependence of compressive stress magnitude in dense polycrystalline Mo films grown by magnetron sputtering. Although Mo is a refractory metal and hence exhibits an intrinsically low mobility, low energy ion bombardment is used during growth to enhance atomic mobility and densify the grain boundaries. Concurrently, the lateral grain size is controlled by using appropriate seed layers on which Mo films are grown epitaxially. The combination of in situ stress monitoring with ex situ microstructural characterization reveals a strong, seemingly linear, increase of the compressive stress magnitude on the inverse grain size and thus provides evidence that compressive stress is generated in the grain boundaries of the film. These results are consistent with models suggesting that compressive stresses in metallic films deposited at high homologous temperatures are generated by atom incorporation into and densification of grain boundaries. However, the underlying mechanisms for grain boundary densification might be different from those in the present study where atomic mobility is intrinsically low. (C) 2016 AIP Publishing LLC.

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