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  • 1.
    Armakavicius, Nerijus
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Bouhafs, Chamseddine
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Stanishev, Vallery
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Kühne, Philipp
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Knight, Sean
    Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, USA.
    Hofmann, Tino
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, USA / Department of Physics and Optical Science, University of North Carolina at Charlotte, USA.
    Schubert, Mathias
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, USA.
    Darakchieva, Vanya
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Cavity-enhanced optical Hall effect in epitaxial graphene detected at terahertz frequencies2017In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 421, p. 357-360Article in journal (Refereed)
    Abstract [en]

    Cavity-enhanced optical Hall effect at terahertz (THz) frequencies is employed to determine the free charge carrier properties in epitaxial graphene (EG) with different number of layers grown by high-temperature sublimation on 4H-SiC(0001). We find that one monolayer (ML) EG possesses p-type conductivity with a free hole concentration in the low 1012 cmᅵᅵᅵ2 range and a free hole mobility parameter as high as 1550 cm2/Vs. We also find that 6 ML EG shows n-type doping behavior with a much lower free electron mobility parameter of 470 cm2/Vs and an order of magnitude higher free electron density in the low 1013 cmᅵᅵᅵ2 range. The observed differences are discussed. The cavity-enhanced THz optical Hall effect is demonstrated to be an excellent tool for contactless access to the type of free charge carriers and their properties in two-dimensional materials such as EG.

  • 2.
    Atakan, Aylin
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Mesoporous material systems for catalysis and drug delivery2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Hybrid material systems possess multi-functional properties which make them intriguing for the materials science community since very early dates. However, it is not straightforward to produce such material systems. A smart and efficient approach is necessary to extract the desired properties of each component under the desired conditions. This study evolved to its last form primarily around this notion, where the development of a hybrid material is the core of the work. This hybrid material is then further explored for two different applications in the catalysis and drug delivery fields.

    A nanoassembly was established around a mesoporous silica support. SBA-15 was picked as this support among the other mesoporous silica due to its well-defined pore structure and accessible pore volume. The silica framework was doped with Zr atoms and the pores were partly infiltrated with Cu nanoparticles resulting in a hybrid material with tunable properties. SBA-15 was synthesized by a sol-gel method where a micellar solution was employed as a template for the silica framework. To achieve the doped version, a Zr precursor was added to the synthesis solution. The effects of different synthesis conditions, such as the synthesis catalyst (F-or a Cl-salt) and the Si source (tetraethyl orthosilicate (TEOS) or sodium metasilicate (SMS)) on the characteristics of the final material were investigated. It was observed that these changes in the synthesis conditions yielded different particle morphology, pore size (11-15 nm), and specific surface area (400-700 m2/g). Cu nanoparticles (NPs) were grown in the (Zr-)SBA-15 support using infiltration (Inf) or evaporation induced wetness impregnation (EIWI) methods. The infiltration method is based on functionalizing the (Zr-)SBA-15 support surfaces before the Cu ion attachment whereas EIWI is based on slow evaporation of the liquid from the (Zr-)SBA-15 - Cu aqueous suspension. Both methods are designed to yield preferential growth of Cu NPs in the pores with a diameter smaller than 10 nm and in oxidized form. However, depending on the loading method used, different chemical states of the final material were achieved, i.e. Zr content and porous network properties are different. 

    Cu-Zr-SBA-15 nanoassemblies produced under various synthesis conditions were used for the catalytic conversion of CO2into valuable fuels such as methanol and dimethyl ether (DME). The effect of different chemical states of the catalyst arising from variations in the synthesis parameters was investigated. It was found that the Si precursor (TEOS or SMS) had a considerable impact on the overall performance of the catalyst whereas the Cu loading method (Inf or EIWI) changed the catalytic selectivity between DME and methanol. The activity of the catalyst was further investigated in a time-evolution study where the accumulation of each product in the gas phase and the molecular groups attached to the catalyst surface were recorded over time. Accordingly, thermodynamic equilibrium was achieved on the 14th day of the reaction under 250°C and 33 bar. The resulting total CO2conversion was 24%, which is the thermodynamically highest possible conversion, according to theoretical calculations. It was also concluded from the experimental results that, DME is formed by a combination of two methoxy surface groups. Additionally, the formation of DME boosts the total CO2conversion to fuels, which otherwise is limited to 9.5%.

    The design of Cu-Zr-SBA-15 was also investigated for drug delivery applications, due to its potential as a biomaterial, e.g., a filler in dental composites, and the antibacterial properties of Cu. Also, the bioactivity of SiO2and ZrO2was considered to be an advantage. With this aim, Cu infiltrated Zr doped SBA-15 material was prepared by using TEOS as the silica precursor and the Inf-method to grow Cu NPs. The performance of the final material as a drug delivery vehicle was tested by an in-vitro delivery study with chlorhexidine digluconate.The nanoassemblies show a drug loading capacity of 25-40% [mg drug / mg (drug+carrier)]. The drug release was determined to be composed of two steps. First, a burst release of the drug molecules that are loosely held in the voids of the mesoporous carrier followed by the diffusion of the drug molecules that are attached to the carrier surface. The presence of Zr and Cu limits the burst release and beneficially slows down the drug release process. 

    The effect of pore properties of SBA-15 was explored in a study where the antibiotic doxycycline hyclate was loaded in SBA-15 materials with different pore sizes. It was observed that the pore size is directly proportional to the drug loading capacity [mg drug / mg (drug+carrier)] and the released drug percentage (the released drug amount/total amount of loaded drug). The drug release was fast due to its weak interactions with the SBA-15 materials. 

    In summary, this work demonstrates the multifunctional character of a smart-tailored nanoassembly which gives valuable insights for two distinct applications in catalysis and drug delivery.

    List of papers
    1. Synthesis of a Cu-infiltrated Zr-doped SBA-15 catalyst for CO2 hydrogenation into methanol and dimethyl ethert
    Open this publication in new window or tab >>Synthesis of a Cu-infiltrated Zr-doped SBA-15 catalyst for CO2 hydrogenation into methanol and dimethyl ethert
    Show others...
    2017 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, no 29, p. 19139-19149Article in journal (Refereed) Published
    Abstract [en]

    A catalytically active nanoassembly comprising Cu-nanoparticles grown on integrated and active supports (large pore Zr-doped mesoporous SBA-15 silica) has been synthesized and used to promote CO2 hydrogenation. The doped mesoporous material was synthesized using a sal-gel method, in which the pore size was tuned between 11 and 15 nm while maintaining a specific surface area of about 700 m(2) g (1). The subsequent Cu nanoparticle growth was achieved by an infiltration process involving attachment of different functional groups on the external and internal surfaces of the mesoporous structure such that 7-10 nm sized Cu nanoparticles grew preferentially inside the pores. Chemisorption showed improved absorption of both CO2 and H-2 for the assembly compared to pure SBA-15 and 15% of the total CO2 was converted to methanol and dimethyl ether at 250 degrees C and 33 bar.

    Place, publisher, year, edition, pages
    ROYAL SOC CHEMISTRY, 2017
    National Category
    Materials Chemistry
    Identifiers
    urn:nbn:se:liu:diva-139804 (URN)10.1039/c7cp03037a (DOI)000406334300033 ()28702581 (PubMedID)
    Note

    Funding Agencies|EUs Erasmus-Mundus program; Swedish Research Council; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 11 2009-00971]; Knut och Alice Wallenbergs Foundation [KAW 2012.0083]

    Available from: 2017-08-17 Created: 2017-08-17 Last updated: 2018-04-16
    2. Time evolution of the CO2 hydrogenation to fuels over Cu-Zr-SBA-15 catalysts
    Open this publication in new window or tab >>Time evolution of the CO2 hydrogenation to fuels over Cu-Zr-SBA-15 catalysts
    Show others...
    2018 (English)In: Journal of Catalysis, ISSN 0021-9517, E-ISSN 1090-2694, Vol. 362, p. 55-64Article in journal (Refereed) Published
    Abstract [en]

    Time evolution of catalytic CO2 hydrogenation to methanol and dimethyl ether (DME) has been investigated in a high-temperature high-pressure reaction chamber where products accumulate over time. The employed catalysts are based on a nano-assembly composed of Cu nanoparticles infiltrated into a Zr doped SiOx mesoporous framework (SBA-15): Cu-Zr-SBA-15. The CO2 conversion was recorded as a function of time by gas chromatography-mass spectrometry (GC-MS) and the molecular activity on the catalyst’s surface was examined by diffuse reflectance in-situ Fourier transform infrared spectroscopy (DRIFTS). The experimental results showed that after 14 days a CO2 conversion of 25% to methanol and DME was reached when a DME selective catalyst was used which was also illustrated by thermodynamic equilibrium calculations. With higher Zr content in the catalyst, greater selectivity for methanol and a total 9.5% conversion to methanol and DME was observed, yielding also CO as an additional product. The time evolution profiles indicated that DME is formed directly from methoxy groups in this reaction system. Both DME and methanol selective systems show the thermodynamically highest possible conversion.

    Keywords
    Cu-Zr-SBA-15, CO2 hydrogenation, Catalysis, Time evolution, Thermodynamics, Methanol, Dimethyl ether
    National Category
    Nano Technology Physical Chemistry
    Identifiers
    urn:nbn:se:liu:diva-147297 (URN)10.1016/j.jcat.2018.03.023 (DOI)000432770900007 ()
    Note

    Funding agencies: EUs Erasmus-Mundus program (The European School of Materials Doctoral Programme - DocMASE); Knut och Alice Wallenbergs Foundation [KAW 2012.0083]; Swedish Government Strategic Research Area (SFO Mat LiU) [2009 00971]; Swedish Energy Agency [42022-1]

    Available from: 2018-04-16 Created: 2018-04-16 Last updated: 2018-06-14Bibliographically approved
  • 3.
    Chen, Kai
    et al.
    Nanjing University, Peoples R China; Nanjing University, Peoples R China; Nanjing University of Science and Technology, Peoples R China.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Lin, Weiwei
    Nanjing University, Peoples R China; Nanjing University, Peoples R China.
    Cai, Hongling
    Nanjing University, Peoples R China; Nanjing University, Peoples R China.
    Li, Guolin
    Nanjing University, Peoples R China; Nanjing University, Peoples R China.
    Dong, Xingwei
    Nanjing University, Peoples R China; Nanjing University, Peoples R China.
    Peng, Song
    Nanjing University, Peoples R China; Nanjing University, Peoples R China.
    Wu, Xiaoshan
    Nanjing University, Peoples R China; Nanjing University, Peoples R China.
    Yang, Mao
    Nanjing University, Peoples R China; Nanjing University, Peoples R China.
    Du, Jun
    Nanjing University, Peoples R China; Nanjing University, Peoples R China.
    Lu, Xiaomei
    Nanjing University, Peoples R China; Nanjing University, Peoples R China.
    Liu, Junming
    Nanjing University, Peoples R China; Nanjing University, Peoples R China.
    Zhu, Jinsong
    Nanjing University, Peoples R China; Nanjing University, Peoples R China.
    Room-temperature multiferroic properties in NiBi2O42010In: Europhysics letters, ISSN 0295-5075, E-ISSN 1286-4854, Vol. 89, no 2, article id 27004Article in journal (Refereed)
    Abstract [en]

    Magnetism and ferroelectricity at room temperature are observed in the NiBi2O4 ceramics. Both the time reversal and the inversion symmetry of the structure (space group F-43m) are broken. The saturation magnetization is 0.028 emu/g and the saturation polarization 2P(s) similar to 4.0 mu C/cm(2). NiBi2O4 also shows other room-temperature multiferroic properties, e. g. the piezoelectric coefficient (d(33)), the polarized dielectric character, the magneto-dielectric response and the magnetoelectric effect. Copyright (C) EPLA, 2010

  • 4.
    Elhag, Sami
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Tordera, Daniel
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Deydier, T
    Department of Material Engineering, University of Toulon, FR-83041 Toulon, France .
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    LiU, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Khranovskyy, Volodymyr
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Jonsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Low-temperature growth of polyethylene glycol-doped BiZn2VO6 nanocompounds with enhanced photoelectrochemical properties2017In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 5, no 3, p. 1112-1119Article in journal (Refereed)
    Abstract [en]

    We demonstrate scalable, low-cost and low-temperature (<100 °C) aqueous chemical growth of bismuth–zinc vanadate (BiZn2VO6) nanocompounds by BiVO4 growth on ZnO nanobelts (NBs). The nanocompounds were further doped with polyethylene glycol (PEG) to tune the electronic structure of the materials, as a means to lower the charge carrier recombination rate. The chemical composition, morphology, and detailed nanostructure of the BiZn2VO6 nanocompounds were characterized. They exhibit rice-like morphology, are highly dense on the substrate and possess a good crystalline quality. Photoelectrochemical characterization in 0.1 M lithium perchlorate in carbonate propylene shows that BiZn2VO6 nanocompounds are highly suitable as anodes for solar-driven photoelectrochemical applications, providing significantly better performance than with only ZnO NBs. This performance could be attributed to the heterogeneous catalysis effect at nanocompound and ZnO NB interfaces, which have enhanced the electron transfer process on the electrode surface. Furthermore, the charge collection efficiency could be significantly improved through PEG doping of nanocompounds. The photocurrent density of PEG-doped BiZn2VO6 nanocompounds reached values of 2 mA cm−2 at 1.23 V (vs. Ag/AgCl), over 60% larger than that of undoped BiZn2VO6 nanocompounds. Photoluminescence emission experiments confirmed that PEG plays a crucial role in lowering the charge carrier recombination rate. The presented BiZn2VO6 nanocompounds are shown to provide highly competitive performance compared with other state-of-the art photoelectrodes.

  • 5.
    Halim, Joseph
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Drexel University, PA 19104 USA.
    Chartier, Patrick
    University of Poitiers, France.
    Basyuk, Tatyana
    National Academic Science Ukrain, Ukraine.
    Prikhna, Tatyana
    National Academic Science Ukrain, Ukraine.
    Caspi, Elad N.
    Nucl Research Centre Negev, Israel.
    Barsoum, Michel W.
    Drexel University, PA 19104 USA.
    Cabioch, Thierry
    University of Poitiers, France.
    Structure and thermal expansion of (Cr-x,V1-x)(n+1)AlCn phases measured by X-ray diffraction2017In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 37, no 1, p. 15-21Article in journal (Refereed)
    Abstract [en]

    MAX phases in the (Crx,V1-x)(n+1)AlCn,system were synthesized by reactive sintering or hot isostatic pressing of elemental powders at temperatures between 1400 degrees C and 1600 degrees C. For n=1, a complete range (0 amp;lt;= x amp;lt;= 1) of solid solutions was found; for n=2 and 3 the solubility ranges were 0.25 amp;lt;= x amp;lt;= 0.75 and 0 amp;lt;= x amp;lt;= 0.5, respectively. Powder X-ray diffraction revealed that the lattice parameters of all (Cr-x,V1-x)(n+1)AlCn solid solutions followed Vegards law. The thermal expansion coefficients of the various compounds were determined from Rietveld refinements of X-Ray patterns obtained at temperatures between ambient and 800 degrees C. For the n=1 and 3 phases the thermal expansion coefficients were almost isotropic; those for the n=2, however, were quite anisotropic with the expansion along the a-axis being significantly larger than along the c-axis. As a general trend, vanadium rich compounds have smaller thermal expansion coefficients than their Cr-rich counterparts. (C) 2016 Elsevier Ltd. All rights reserved.

  • 6.
    Ivanov, Ivan Gueorguiev
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yazdanfar, Milan
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lundqvist, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Chen, Jr-Tai
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Stenberg, Pontus
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Son, Nguyen Tien
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ager, Joel W. III
    Lawrence Berkeley National Laboratory, Berkeley, California, USA.
    Kordina, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    High-Resolution Raman and Luminescence Spectroscopy of Isotope-Pure (SiC)-Si-28-C-12, Natural and C-13 - Enriched 4H-SIC2014In: Silicon Carbide and Related Materials 2013, PTS 1 AND 2, Trans Tech Publications Inc., 2014, Vol. 778-780, p. 471-474Conference paper (Refereed)
    Abstract [en]

    The optical properties of isotope-pure (SiC)-Si-28-C-12, natural SiC and enriched with C-13 isotope samples of the 4H polytype are studied by means of Raman and photoluminescence spectroscopies. The phonon energies of the Raman active phonons at the Gamma point and the phonons at the M point of the Brillouin zone are experimentally determined. The excitonic bandgaps of the samples are accurately derived using tunable laser excitation and the phonon energies obtained from the photoluminescence spectra. Qualitative comparison with previously reported results on isotope-controlled Si is presented.

  • 7.
    Knutsson, Axel
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Ullbrand, Jennifer
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Rogström, Lina
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Norrby, Niklas
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Almer, Jonathan
    Argonne National Laboratory, Illinois, USA.
    Johansson, Mats P.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Jansson, Bo
    Seco Tools AB, Fagersta, Sweden.
    Magnus, Odén
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Early stage spinodal decomposition and microstructure evolution in TiAlN: A combined in-situ SAXS and phase field studyManuscript (preprint) (Other academic)
    Abstract [en]

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

  • 8.
    Landälv, Ludvig
    Luleå Tekniska Universitet.
    Samband mellan tjockleken hos PVD-skikt och förslitningsbeteendet vid svarvning2008Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This project has as main goal to study the influence of the coating thickness, deposited by arc-PVD- technology, on the wear resistance of coated cemented carbide inserts in three different turning operations. An additional effort has also been made to develop a new test method for evaluating flank wear resistance. Three different coating types (Coating A, Coating B and Coating C) have been studied in three distinctive thicknesses (2, 4 and 6 μ m) for each type. For two of the coating types (Coating A and B) special studies has been done with the thickest coating, creating two additional coating versions of the thickest coating, by changing various deposition parameters, with the aim to enhance the cohesive properties of the coating and lower the residual stresses at the cutting edge. The results show increased crater wear resistance with increased coating thickness for all coating types, but the amount of increase changes with coating type (Coating A>B>C). Flaking wear resistance decreased with increased coating thickness for all coating types. Further the high temperature version of Coating A, showed a significant increase in the flaking wear resistance compared to the standard version of Coating A. The flank wear test showed an increased resistance with thicker coatings in all cases except for the 6 μ m version of Coating C. The flank wear resistance of the most flank wear resistant coatings (Coating B, C) was also successfully examined in a new developed test method. The method suppressed excessive crater wear on the rake face and presented a high abrasive wear rate on the flank and some flaking on the rake face. The amount of flaking is judged not to influence the testing of the flank wear resistance. For all the tested coatings in the new test an increase in the coating thickness resulted in better flank wear resistance.

  • 9.
    Li, Xun
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Homo-epitaxial growth on low-angle off cut 4H-SiC substrate2014In: SILICON CARBIDE AND RELATED MATERIALS 2013, PTS 1 AND 2, Trans Tech Publications Inc., 2014, Vol. 778-780, p. 131-134Conference paper (Refereed)
    Abstract [en]

    The growth of 4H-SiC epilayers on 1.28 degrees off-cut substrates is reported in this study and comparison when using standard 4 degrees and 8 degrees off-cut substrates is added. Growth at high temperature is needed for the polytype stability, whereas low C/Si is requested to decrease both triangular defects density and roughness of the grown surface. An in-situ etching with Si rich ambient allows the growth of epilayers with specular surface. The formation of Si droplets can be observed on the grown surfaces when lowering the growth temperature and appears first for the high off-cut angle.

  • 10.
    Liang, S.
    et al.
    US DOE-National Energy Technology Laboratory, Pittsburgh, PA, USA and University of Pittsburgh, USA.
    Broitman, Esteban
    Carnegie Mellon University, Pittsburgh, PA, USA .
    Wang, Y.
    US DOE-National Energy Technology Laboratory, Pittsburgh, PA, USA and University of Pittsburgh, USA.
    Cao, A.
    US DOE-National Energy Technology Laboratory, Pittsburgh, PA, USA and University of Pittsburgh, USA.
    Veser, G.
    US DOE-National Energy Technology Laboratory, Pittsburgh, PA, USA and University of Pittsburgh, USA.
    Highly stable, mesoporous mixed lanthanum–cerium oxides with tailored structure and reducibility2011In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 46, no 9, p. 2928-2937Article in journal (Refereed)
    Abstract [en]

    Pure and mixed lanthanum and cerium oxides were synthesized via a reverse microemulsion-templated route. This approach yields highly homogeneous and phase-stable mixed oxides with high surface areas across the entire range of La:Ce ratios from pure lanthana to pure ceria. Surprisingly, all mixed oxides show the fluorite crystal structure of ceria, even for lanthanum contents as high as 90%. Varying the La:Ce ratio not only allows tailoring of the oxide morphology (lattice parameter, pore structure, particle size, and surface area), but also results in a fine-tuning of the reducibility of the oxide which can be explained by the creation of oxygen vacancies in the ceria lattice upon La addition. Such finely controlled syntheses, which enable the formation of stable, homogeneous mixed oxides across the entire composition range, open the path towards functional tailoring of oxide materials, such as rational catalyst design via fine-tuning of redox activity.

  • 11.
    Liu, J. -M.
    et al.
    Nanjing University, Peoples R China; Chinese Academic Science, Peoples R China.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Yuan, G. L.
    Nanjing University, Peoples R China; Chinese Academic Science, Peoples R China.
    Wang, Y.
    Nanjing University, Peoples R China; Chinese Academic Science, Peoples R China.
    Zeng, M.
    Nanjing University, Peoples R China; Chinese Academic Science, Peoples R China.
    Wan, J. G.
    Nanjing University, Peoples R China; Chinese Academic Science, Peoples R China.
    Ferroelectric and magnetoelectric behaviors of multiferroic BiFeO3 and piezoelectric-magnetostrictive composites2008In: Journal of Electroceramics, ISSN 1385-3449, E-ISSN 1573-8663, Vol. 21, no 1-4, p. 78-84Article in journal (Refereed)
    Abstract [en]

    In this paper we overview our recent work on ferroelectric and magnetoelectric coupling behaviors of multiferroic doped BiFeO3 (BFO) and piezoelectric-magnetostrictive composites. Using rapid liquid sintering method we prepare single-phase BFO ceramics of excellent ferroelectric property. The BFO thin films on Pt-coated silicon wafers by pulsed laser deposition show large remnant polarization but serious ferroelectric switching fatigue. A series of piezoelectric-magnetostrictive composite structures in bulk and thin film forms are prepared and giant magnetoelectric coupling effect of them is observed. The experimentally measured results are confirmed by numerical modeling based on piezoelectric and magnetostrictive constitution equations.

  • 12.
    Mockuté, Aurelija
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Palisaitis, Justinas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Nedfors, Nils
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Berastegui, P.
    Uppsala Univ, Sweden.
    Broitman, Esteban
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. SKF Res and Technol Dev Ctr, Netherlands.
    Alling, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Näslund, Lars-Åke
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Patscheider, J.
    Evatec AG, Switzerland.
    Jansson, U.
    Uppsala Univ, Sweden.
    Persson, Per O A
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Synthesis and characterization of (Ti1-xAlx)B2+Delta thin films from combinatorial magnetron sputtering2019In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 669, p. 181-187Article in journal (Refereed)
    Abstract [en]

    (Ti1-xAlx)B2+Delta films with a lateral composition gradient of x = [0.30-0.66] and Delta = [0.07-1.22] were deposited on an Al2O3 wafer by dual magnetron sputtering at 400 degrees C from sintered TiB2 and AlB2 targets. Composition analysis indicates that higher Ti:Al ratios favor overstoichiometry in B and a reduced incorporation of O. Transmission electron microscopy reveals distinctly different microstructures of Ti- and Al-rich compositions, with formation of characteristic conical growth features for the latter along with a lower degree of crystallinity and significantly less tissue phase from B segregation at the grain boundaries. For Al-rich films, phase separation into Ti- and Al-rich diboride nanometer-size domains is observed and interpreted as surface-initiated spinodal decomposition. The hardness of the films ranges from 14 to 28 GPa, where the higher values were obtained for the Ti-rich regions of the metal boride.

    The full text will be freely available from 2020-10-26 15:00
  • 13.
    Pilemalm, Robert
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Theoretical and experimental studies of ternary and quaternary nitrides for machining and thermoelectric materials2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Nitrides are used as coatings and thin films for a wide range of applications. The study and use of nitrides in the recent decades have shifted towards ternary, quaternary or even higher order (complex) nitrides. There is an interest to use ternary and quaternary nitrides for machining and thermoelectric materials, because it gives the possibility to choose composition and thereby design the materials properties. This thesis presents research results on TiAlN and and TiAlN-based coatings that are used as hard coatings for machining and on ternary scandium nitrides that are of interest for thin films for thermoelectric applications. The high-pressure high-temperature behavior of cubic TiAlN deposited on cubic boron nitride has been experimentally studied. It has been shown that the spinodal decomposition, which means decomposition into cubic domains enriched in TiN and AlN, is delayed as a result of high pressure compared to ambient pressure. No chemical interaction between coating and substrate occurs. TiZrAlN has been theoretically and experimentally studied at high temperature. The results show that the when Zr-content is decreased and the Al-content is increased the decomposition route changes from nucleation and growth to spinodal decomposition. The microstructure evolution with temperature depends on the initial composition. In the case where the decompositon starts with only spinodal decomposition the microstructure at 1100 °C consists of domains that are larger than in the case where the decomposition occurs by nucleation and growth. ScMN2 (M=V, Nb, Ta) phases have been experimentally demonstrated for M=Nb and Ta in a few studies, but have not been much investigated. In this theseis, their crystal structure, stability, elastic properties, electronic structure and thermoelectric properties have been studied. At 0 K and 0 GPa it has been shown that these three phases are thermodynamically and elastically stable. Additionally, these are narrow bandgap semiconductors and their thermoelectric properties can be tuned by doping. Pressure has a stabilizing effect on these structures. When pressure increases from 0-150 GPa the elastic constants and moduli increases in the range 53-317 %.

  • 14.
    Saarimäki, Jonas
    et al.
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Lundberg, Mattias
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Moverare, Johan
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Brodin, Håkan
    Linköping University, Department of Management and Engineering. Linköping University, Faculty of Science & Engineering. Siemens Industrial Turbomachinery AB, Finspång.
    3D Residual Stresses in Selective Laser Melted Hastelloy X2017In: Residual Stresses 2016: ICRS-10, Materials Research Proceedings 2 (2016), 2017, Vol. 2, p. 73-78Conference paper (Refereed)
    Abstract [en]

    3D residual stresses in as manufactured EOS NickelAlloy HX, produced by laser powder bed additive manufacturing, are analysed on the surface closest to the build-plate. Due to the severe thermal gradient produced during the melting and solidification process, profound amounts of thermal strains are generated. Which can result in unwanted geometrical distortion and effect the mechanical properties of the manufactured component. Measurements were performed using a four-circle goniometer Seifert X-ray machine, equipped with a linear sensitive detector and a Cr-tube. Evaluation of the residual stresses was conducted using sin2ψ method of the Ni {220} diffraction peak, together with material removal technique to obtain in-depth profiles. An analysis of the material is reported. The analysis reveals unwanted residual stresses, and a complicated non-uniform grain structure containing large grains with multiple low angle grain boundaries together with nano-sized grains. Grains are to a large extent, not equiaxed, but rather elongated.

  • 15.
    Soomro, Muhammad Yousuf
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Hussain, Ijaz
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Bano, Nargis
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Broitman, Esteban
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nanoscale elastic modulus of single horizontal ZnO nanorod using nanoindentation experiment2012In: Nanoscale Research Letters, ISSN 1931-7573, E-ISSN 1556-276X, Vol. 7, p. 146-148Article in journal (Refereed)
    Abstract [en]

    We measure the elastic modulus of a single horizontal ZnO nanorod [NR] grown by a low-temperature hydrothermal chemical process on silicon substrates by performing room-temperature, direct load-controlled nanoindentation measurements. The configuration of the experiment for the single ZnO NR was achieved using a focused ion beam/scanning electron microscope dual-beam instrument. The single ZnO NR was positioned horizontally over a hole on a silicon wafer using a nanomanipulator, and both ends were bonded with platinum, defining a three-point bending configuration. The elastic modulus of the ZnO NR, extracted from the unloading curve using the well-known Oliver-Pharr method, resulted in a value of approximately 800 GPa. Also, we discuss the NR creep mechanism observed under indentation. The mechanical behavior reported in this paper will be a useful reference for the design and applications of future nanodevices.

  • 16.
    Spencer, C B
    et al.
    Drexel University.
    Cordoba Gallego, Jose Manuel
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Obando, N
    Texas A&M University.
    Sakulich, A
    Drexel University.
    Radovic, M
    Texas A&M University.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials . Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Barsoum, M W
    Drexel University.
    Phase Evaluation in Al(2)O(3) Fiber-Reinforced Ti(2)AlC During Sintering in the 1300 degrees C-1500 degrees C Temperature Range2011In: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 94, no 10, p. 3327-3334Article in journal (Refereed)
    Abstract [en]

    In this article, the reactivity of Ti(2)AlC powders, with 3 and 10 mu m alumina, Al(2)O(3), fibers during pressure-assisted sintering is explored. Samples were fabricated by hot-isostatic-pressing (HIPed) or hot-pressing (HPed), and characterized by X-ray diffraction, differential thermal analysis, and electron microscopy-both scanning and transmission-equipped with energy dispersive X-ray spectroscopes. Samples prepared at 1300 degrees C were fully dense, with no apparent reaction between fiber and matrix. In samples HPed to 1500 degrees C, even pure Ti(2)AlC powders dissociated to Ti(3)AlC(2) according to: 2 Ti(2)AlC = Ti(3)AlC(2) + TiAl(x) (l) + (1-x) Al (l/v), with x andlt; 1. More severe Al loss results in the formation of TiC(y). The presence of the Al(2)O(3) fibers delayed densification enough to allow most of the Al and some of the Ti to escape into the vacuum of the hot press or react with the encapsulating glass during HIPing a resulting in a more intensive dissociation of the Ti(2)AlC. Although, in principle Ti(2)AlC can be reinforced with Al(2)O(3) fibers, the processing/use temperature will have to be kept below 1500 degrees C, as, at that temperature the fibers, used here, sinter together.

  • 17.
    Sun, Jun
    et al.
    Tech Univ Denmark, Denmark; Xnovo Technol, Denmark.
    Yu, Tianbo
    Tech Univ Denmark, Denmark.
    Xu, Chaoling
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Ludwig, Wolfgang
    ESRF, France; Univ Lyon, France.
    Zhang, Yubin
    Tech Univ Denmark, Denmark.
    3D characterization of partially recrystallized Al using high resolution diffraction contrast tomography2018In: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 157, p. 72-75Article in journal (Refereed)
    Abstract [en]

    Synchrotron diffraction contrast tomography (DCT) is for the first time used to characterize recrystallized grains in partially recrystallized Al. The positions, orientations and 3D shapes of amp;gt;900 recrystallized grains are reconstructed within a gauge volume. The results are compared with those obtained using electron backscattered diffraction based on a statistical analysis. It is found that recrystallized grains with size larger than 10 mu m, corresponding to similar to 98% of the total recrystallized volume of the sample, are well characterized by DCT. The advantages of DCT for recrystallization studies and new possibilities with DCT on new generation synchrotron sources are discussed. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  • 18.
    Trinh, Xuan Thang
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Szasz, K.
    Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Hungary.
    Hornos, T.
    Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Hungary.
    Kawahara, K.
    Institute of Physics, Loránd Eötvös University, Hungary.
    Suda, J.
    Institute of Physics, Loránd Eötvös University, Hungary.
    Kimoto, T.
    Institute of Physics, Loránd Eötvös University, Hungary.
    Gali, Ádam
    Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Hungary, Department of Electronic Science and Engineering, Kyoto University, Japan.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Son, Nguyen Tien
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Identification of the negative carbon vacancy at quasi-cubic site in 4H-SiC by EPR and theoretical calculations2014In: Silicon Carbide and Related Materials 2013, PTS 1 AND 2, Trans Tech Publications Inc., 2014, Vol. 778-780, p. 285-288Conference paper (Refereed)
    Abstract [en]

    In freestanding n-type 4H-SiC epilayers irradiated with low-energy (250 keV) electrons at room temperature, the electron paramagnetic resonance (EPR) spectrum of the negative carbon vacancy at the hexagonal site, V-C(-)(h), and a new signal were observed. From the similarity in defect formation and the spin-Hamiltonian parameters of the two defects, the new center is suggested to be the negative C vacancy at the quasi-cubic site, V-C(-)(k). The identification is further supported by hyperfine calculations.

  • 19.
    Ullbrand, Jennifer
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Grönhagen, Klara
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Tasnádi, Ferenc
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Jansson, Bo
    Seco Tools AB, Fagersta, Sweden.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Microstructure evolution of TiAlN-a phase field studyManuscript (preprint) (Other academic)
    Abstract [en]

    In this work the phase field method has been applied to model the spinodal decomposition of TiAlN. Here we have used thermodynamic data from ab initio calculations that takes into account clustering effects, and experimental diffusivity data of TiAlN as an input to the model. The effect of alloy composition on microstructure and stresses, is studied in time and space. In addition, Young’s modulus evolution of the decomposing microstructure is reported. It was found that the microstructure changes from round AlN rich domains in a TiN matrix, to outstretched TiN rich domains in the {100} crystallographic directions in an AlN matrix, as the composition was changed from x=0.3 to x=0.75 in Ti1-xAlxN. The microstructure evolution was observed to undergo different stages. In short; first elongated structures enriched of the majority element in random directions evolve. Thereafter round AlN rich domains evolve, independent of composition studied, and a completely segregated microstructure forms that finally coarsens. The initiation, decomposition, and coarsening rate was found to increase with Al content due to the increase in driving force with Al content. Al rich domains purify fastest, independent of composition studied. The evolving compositional wavelength decreases with Al content resulting in a finer microstructure for alloys rich in Al. During decomposition high local strains and stresses develop, which reach maximum values of 6·10-3 and 12 GPa respectively.

  • 20.
    Yuan, F.
    et al.
    Nanjing University, Peoples R China.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Wang, K. F.
    Nanjing University, Peoples R China.
    Dong, S.
    Nanjing University, Peoples R China.
    Wang, Y.
    Nanjing University, Peoples R China.
    Liu, J. -M.
    Nanjing University, Peoples R China.
    Effect of Pr doping on ferroelectric behaviors of Pb(Zr0.65Ti0.35)O-32008In: International Journal of Modern Physics B, ISSN 0217-9792, Vol. 22, no 13, p. 2070-2081Article in journal (Refereed)
    Abstract [en]

    Pr-doped Pb(Zr0.65Ti0.35)O-3 (Pb1-xPr (Zr0.65Ti0.35)(1-x)/O-4(3), PPZT) ceramic samples are prepared using conventional solid-state sintering method, and their structural, dielectric, ferroelectric, and piezoelectric properties are investigated, focusing on the effects of Pr-doping. Upon increasing Pr doping level x, a transition of the crystallographic structure from rhombohedral symmetry to tetrahedral and finally to pseudocubic symmetry is observed at x similar to 0.08. The detailed dielectric measurements present a clear indication of relaxor-like behaviors at x = 0.08, while the samples at x less than 0.08 offer slightly improved ferroelectric properties compared with pure Pb(Zr0.65Ti0.35)O-3. In spite of the dielectric relaxor behaviors induced by Pr-doping, both the ferroelectric and piezoelectric properties of PPZT are degraded at x = 0.08. The physics underlying the Pr-doping induced relaxor behaviors is then discussed.

  • 21.
    Zhang, Pimin
    et al.
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering. Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Sadeghimeresht, Esmaeil
    Högskolan Väst, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Peng, Ru Lin
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Li, Xin-Hai
    Siemens Industrial Turbomachinery AB, Finspång, Sweden.
    Markocsan, Nicolaie
    Högskolan Väst, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Joshi, Shrikant
    Högskolan Väst, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Johansson, Sten
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Isothermal oxidation behavior of HVAF-sprayed NiCoCrAlY coatings: Effect of surface treatment2017In: Proceedings of International Thermal Sprayed Conference (ITSC), May 7-9,Germany, 456-461 (2017), 2017, p. 456-461Conference paper (Other academic)
    Abstract [en]

    NiCoCrAlY coatings are widely used as bond coats for ceramic thermal barrier coatings (TBCs) andoxidation and corrosion protective overlay coatings in industrial gas turbines. High temperature oxidation behaviour of NiCoCrAlYs has a great influence on the coating performance and lifetime of TBCs. A promising route to decrease the oxidation rate of such coatings is post-coating surface modification which can facilitate formation of a uniform alumina scale with a considerably slower growth rate compared to the as-sprayed coatings. In this work, the effect of surface treatment by means of shot peening and laser surface melting (LSM) on the oxidation resistance of high velocity air-fuel (HVAF) sprayed NiCoCrAlY coatings was studied. Isothermal oxidation was carried out at 1000⁰C for 1000h. Results showed that the rough surface of as-sprayed HVAF sprayed coatings was significantly changed after shot peening and LSM treatment, with a compact and smooth appearance. After the exposure, the oxide scales formed on surface-treated NiCoCrAlY coatings showed different morphology and growth rate compared to those formed on as-sprayed coating surface. The oxidation behaviour of surface treated HVAF-sprayed NiCoCrAlY coatings were revealed and discussed.

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