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Publications (10 of 13) Show all publications
Fritze, S., Hahn, R., Aboulfadl, H., Johansson, F. O. .., Lindblad, R., Böör, K., . . . Thuvander, M. (2024). Elemental distribution and fracture properties of magnetron sputtered carbon supersaturated tungsten films. Surface & Coatings Technology, 477, Article ID 130326.
Open this publication in new window or tab >>Elemental distribution and fracture properties of magnetron sputtered carbon supersaturated tungsten films
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2024 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 477, article id 130326Article in journal (Refereed) Published
Abstract [en]

The combination of strength and toughness is a major driving force for alloy design of protective coatings, and nanocrystalline tungsten (W)-alloys have shown to be promising candidates for combining strength and toughness. Here we investigate the elemental distribution and the fracture toughness of carbon (C) alloyed W thin films prepared by non-reactive magnetron sputtering. W:C films with up to ~4 at.% C crystallize in a body-centered-cubic structure with a strong 〈hh0〉texture, and no additional carbide phases are observed in the diffraction pattern. Atom probe tomography and X-ray photoelectron spectroscopy confirmed the formation of such a supersaturated solid solution. The pure W film has a hardness ~13 GPa and the W:C films exhibit a peak hardness of ~24 GPa. In-situ micromechanical cantilever bending tests show that the fracture toughness decreases from ~4.5 MPa·m1/2 for the W film to ~3.1 MPa·m1/2 for W:C films. The results show that C can significantly enhance the hardness of W thin films while retaining a high fracture toughness.

Place, publisher, year, edition, pages
Elsevier, 2024
Keywords
PVD, Fracture toughness, Atom probe tomography, XPS, Tungsten
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-521828 (URN)10.1016/j.surfcoat.2023.130326 (DOI)001149676000001 ()
Funder
Swedish Foundation for Strategic Research, RMA15-0048
Available from: 2024-01-29 Created: 2024-01-29 Last updated: 2024-02-15Bibliographically approved
Osinger, B. (2024). Investigation of compositionally complex refractory metal based thin films. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Investigation of compositionally complex refractory metal based thin films
2024 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The search for new and improved materials has led to the discovery and establishment of compositionally complex or high-entropy materials. The work in this thesis is focused on the investigation of new compositionally complex materials based on the refractory metals of groups 4-6. The materials in this work were synthesised using non-reactive dc magnetron sputtering and three material systems have been studied: HfNbTiVZr-C, CrTiTaWNb-C and Nb-Mo-C. In the context of compositionally complex materials, this thesis aims to contribute specifically to questions regarding (i) the prediction of phase formation and stability (ii) the chemical interaction between atoms (iii) the correlation between the material properties and compositional complexity. 

The prediction of phase formation and stability using calculated phase diagram (CALPHAD) methods was studied in the HfNbTiVZr-C system. The findings suggest that CALPHAD methods are promising predictive tools, although kinetic effects during synthesis need to be taken into consideration. Furthermore, theoretical, and experimental evidence of charge transfer effects was demonstrated within the HfNbTiVZr-C system. The results of ab initio materials simulations and X-ray Photoelectron Spectroscopy (XPS) measurements highlight the importance of understanding and considering the local chemical environment and chemical interactions in compositionally complex materials.

The approach of metal alloying according to the valence electron concentration (VEC) to tune the mechanical properties was studied in the Nb-Mo-C system. The findings show the importance of microstructural effects on the mechanical properties in the studied thin film materials, which can overshadow the compositional or VEC variations. 

The response to Xe heavy-ion irradiation was studied in the CrTiTaWNb-C system using in situ irradiation experiments. This work presents a comparison between three different compositions: a TaW-rich alloy and carbide thin film as well as a near-equimolar carbide film. The findings indicate that both microstructure and chemical homogeneity play important roles when it comes to radiation damage tolerance in compositional complex materials.

This thesis demonstrates the elaborate and multifaceted nature of compositionally complex materials. Whether it comes to the fundamental understanding or the effective implementation of a materials design tool, many factors need to be taken into consideration, including chemical interactions between the constituent elements and microstructural effects.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2024. p. 70
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 2355
Keywords
Magnetron sputtering, Thin films, High entropy materials, Refractory metals, Transition metal carbides
National Category
Materials Chemistry
Research subject
Chemistry with specialization in Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-517268 (URN)978-91-513-2007-6 (ISBN)
Public defence
2024-03-01, Häggsalen - Ångströmlaboratory, Lägerhyddsvägen 1, Uppsala, 09:15 (English)
Opponent
Supervisors
Funder
Swedish Research Council, 2018-04834
Available from: 2024-02-07 Created: 2024-01-11 Last updated: 2024-02-07
Tunes, M. A., Fritze, S., Osinger, B., Willenshofer, P., Alvarado, A. M., Martinez, E., . . . El-Atwani, O. (2023). From high-entropy alloys to high-entropy ceramics: The radiation-resistant highly concentrated refractory carbide (CrNbTaTiW)C. Acta Materialia, 250, Article ID 118856.
Open this publication in new window or tab >>From high-entropy alloys to high-entropy ceramics: The radiation-resistant highly concentrated refractory carbide (CrNbTaTiW)C
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2023 (English)In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 250, article id 118856Article in journal (Refereed) Published
Abstract [en]

High-entropy materials represent the state-of-the-art on the alloy design strategy for future applications in extreme environments. Recent data indicates that high-entropy alloys (HEAs) exhibit outstanding radiation resistance in face of existing diluted alloy counterparts due to suppressed damage formation and evolution. An extension of the HEA concept is presented in this paper towards the synthesis and characterization of novel high-entropy ceramics as emergent materials for application in environments where energetic particle irradiation is a major concern. A novel carbide within the quinary refractory system CrNbTaTiW has been synthesized using magnetron-sputtering. The material exhibited nanocrystalline grains, single-phase crystal structure and C content around 50 at.%. Heavy-ion irradiation with in-situ Transmission Electron Microscopy was used to assess the irradiation response of the new high-entropy carbide (HEC) at 573 K and a comparison with the HEA within the system is made. No displacement damage effects appear within the microstructures of both HEA and HEC up to a dose of 10 displacements-per-atom. Surprisingly, the HEC has not amorphized under the investigated conditions. Xe was implanted in both materials and bubbles nucleated, but smaller sizes compared with conventional nuclear materials shedding light they are potential candidates for use in nuclear energy.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
High-entropy ceramics, High-entropy alloys, Nanocrystalline materials, Radiation damage, Extreme environments
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-499313 (URN)10.1016/j.actamat.2023.118856 (DOI)000958714700001 ()
Funder
EU, European Research Council, 757961Swedish Research Council, 2017-00646_9Swedish Research Council, 2019_00191Swedish Foundation for Strategic Research, RIF14-0053
Available from: 2023-03-27 Created: 2023-03-27 Last updated: 2024-01-11Bibliographically approved
Osinger, B., Mao, H., Fritze, S., Riekehr, L., Jansson, U. & Lewin, E. (2022). Investigation of the phase formation in magnetron sputtered hard multicomponent (HfNbTiVZr)C coatings. Materials & design, 221, Article ID 111002.
Open this publication in new window or tab >>Investigation of the phase formation in magnetron sputtered hard multicomponent (HfNbTiVZr)C coatings
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2022 (English)In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 221, article id 111002Article in journal (Refereed) Published
Abstract [en]

Multicomponent carbides have gained interest especially for ultra-high temperature applications, due to their ceramic hardness, good oxidation resistance and enhanced strength. In this study the phase forma-tion, stability and mechanical properties of (HfNbTiVZr)C multicomponent carbide coatings were inves-tigated. Phase stability was predicted by the CALPHAD (CALculation of PHAse Diagrams) methods. This revealed that the multicomponent solid solution phase is only stable at elevated temperatures, namely above 2400 degrees C. At lower temperatures a phase mixture was predicted, with a particular tendency for V to segregate. Magnetron sputtered thin films deposited at 300 degrees C exhibited a single NaCl-type multicom-ponent carbide phase, which attributes to the kinetic stabilisation of simple structures during thin film growth. Films deposited at 700 degrees C, or exposed to UHV annealing at 1000 degrees C, however, revealed the decom-position of the single-phase multicomponent carbide by partial elemental segregation and formation of additional phases. Thus, confirming the CALPHAD predictions. These results underscore the importance of explicitly considering temperature when discussing the stability of multicomponent carbide materials, as well as the applicability of CALPHAD methods for predicting phase formation and driving forces in these materials. The latter being crucial for designing materials, such as carbides, that are used in appli-cations at elevated temperatures.

Place, publisher, year, edition, pages
ElsevierElsevier BV, 2022
Keywords
High entropy ceramics, Multi -principal element carbide, Multicomponent carbide, Physical vapour deposition (PVD), CALPHAD
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-482676 (URN)10.1016/j.matdes.2022.111002 (DOI)000839257000004 ()
Funder
Swedish Research Council, 2018-04834Swedish Research CouncilSwedish Research Council, 2017-00646_9Swedish Foundation for Strategic Research, RIF14-0053
Available from: 2022-09-07 Created: 2022-09-07 Last updated: 2024-01-15Bibliographically approved
Mukhamedov, B., Fritze, S., Ottosson, M., Osinger, B., Lewin, E., Alling, B., . . . Abrikosov, I. (2022). Tetragonal distortion in magnetron sputtered bcc-W films with supersaturated carbon. Materials & design, 214, Article ID 110422.
Open this publication in new window or tab >>Tetragonal distortion in magnetron sputtered bcc-W films with supersaturated carbon
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2022 (English)In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 214, article id 110422Article in journal (Refereed) Published
Abstract [en]

Carbon has a low solid solubility in bcc tungsten at equilibrium. However, metastable supersaturated solid solutions can be synthesized with magnetron sputtering. Here, we present a systematic study on the phase stability and mechanical properties of such supersaturated W–C solid solutions. Θ–2θ scans show a split of the 200/020 and the 002 peaks for supersaturated films which is explained by a tetragonal distortion of the bcc structure. This split increases with increasing C content and is maximized at 4 at.% C, where we observe an a/b axis of 3.15–3.16 Å and a c-axis of 3.21–3.22 Å. We performed first-principles calculations of lattice parameters, mixing enthalpies, elastic constants and polycrystalline elastic moduli for cubic and tetragonal W–C solid solutions. Calculations show that tetragonal structure is more stable than the bcc supersaturated solid solution and the calculated lattice parameters and Young’s moduli follow the same trends as the experimental ones as a function of C concentration. The results suggest that supersaturated films with lattice distortion can be used as a design approach to improve the properties of transition metal films with a bcc structure.

Place, publisher, year, edition, pages
ElsevierElsevier BV, 2022
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-470304 (URN)10.1016/j.matdes.2022.110422 (DOI)000761243900006 ()
Funder
Swedish Foundation for Strategic Research , 2019-05403Swedish Foundation for Strategic Research , FFL 15-0290Linköpings universitetKnut and Alice Wallenberg Foundation, KAW-2018.0194Swedish Research Council, 2009 00971Swedish Research Council, 2018-04834
Available from: 2022-03-22 Created: 2022-03-22 Last updated: 2024-01-15Bibliographically approved
Casillas-Trujillo, L., Osinger, B., Lindblad, R., Karlsson, D., Abrikosov, A. I., Fritze, S., . . . Lewin, E. (2021). Experimental and theoretical evidence of charge transfer in multi-component alloys: how chemical interactions reduce atomic size mismatch. Materials Chemistry Frontiers, 5(15), 5746-5759
Open this publication in new window or tab >>Experimental and theoretical evidence of charge transfer in multi-component alloys: how chemical interactions reduce atomic size mismatch
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2021 (English)In: Materials Chemistry Frontiers, E-ISSN 2052-1537, Vol. 5, no 15, p. 5746-5759Article in journal (Refereed) Published
Abstract [en]

Ab initio simulations of a multi-component alloy using density functional theory (DFT) were combined with experiments on thin films of the same material using X-ray photoelectron spectroscopy (XPS) to study the connection between the electronic and atomic structures of multi-component alloys. The DFT simulations were performed on an equimolar HfNbTiVZr multi-component alloy. Structure and charge transfer were evaluated using relaxed, non-relaxed, as well as elemental reference structures. The use of a fixed sphere size model allowed quantification of charge transfer, and separation into different contributions. The charge transfer was generally found to follow electronegativity trends and results in a reduced size mismatch between the elements, and thus causes a considerable reduction of the lattice distortions compared to a traditional assumption based on tabulated atomic radii. A calculation of the average deviation from the average radius (i.e. the so-called δ-parameter) based on the atomic Voronoi volumes gave a reduction of δ from ca. 6% (using the volumes in elemental reference phases) to ca. 2% (using the volumes in the relaxed multi-component alloy phase). The reliability of the theoretical results was confirmed by XPS measurements of a Hf22Nb19Ti18V19Zr21 thin film deposited by sputter deposition. The experimentally observed core level binding energy shifts (CLS), as well as peak broadening due to a range of chemical surroundings, for each element showed good agreement with the calculated DFT values. The single solid solution phase of the sample was confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) including energy dispersive spectroscopy (EDS) with nm-resolution. These observations show that the HfNbTiVZr solid solution phase is non-ideal, and that chemical bonding plays an important part in the structure formation, and presumably also in the properties. Our conclusions should be transferable to other multi-component alloy systems, as well as some other multi-component material systems, and open up interesting possibilities for the design of material properties via the electronic structure and controlled charge transfer between selected metallic elements in the materials.

Place, publisher, year, edition, pages
Royal Society of ChemistryRoyal Society of Chemistry (RSC), 2021
National Category
Materials Chemistry Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-468314 (URN)10.1039/d1qm00380a (DOI)000664149100001 ()
Funder
Swedish Research Council, 2018-04834Swedish Research Council, 2019-05403Swedish Research Council, 2018-05973Swedish Research Council, 2019-05487Knut and Alice Wallenberg Foundation, KAW-2018.0194Swedish Foundation for Strategic Research , FFL 15-0290Swedish National Infrastructure for Computing (SNIC)
Available from: 2022-02-25 Created: 2022-02-25 Last updated: 2024-01-15Bibliographically approved
Fritze, S., Chen, M., Riekehr, L., Osinger, B., Sortica, M. A., Srinath, A., . . . Jansson, U. (2021). Magnetron sputtering of carbon supersaturated tungsten films-A chemical approach to increase strength. Materials & design, 208, Article ID 109874.
Open this publication in new window or tab >>Magnetron sputtering of carbon supersaturated tungsten films-A chemical approach to increase strength
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2021 (English)In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 208, article id 109874Article in journal (Refereed) Published
Abstract [en]

Tungsten (W)-based materials attract significant attention due to their superior mechanical properties. Here, we present a chemical approach based on the addition of carbon (C) for increased strength via the combination of three strengthening mechanisms in W thin films. W:C thin films with C concentrations up to-4 at.% were deposited by magnetron sputtering. All films exhibit a body-centred-cubic structure with strong texture and columnar growth behaviour. X-ray and electron diffraction measurements suggest the formation of supersaturated W:C solid solution phases. The addition of C reduced the average column width from-133 nm for W to-20 nm for the film containing-4 at.% C. The column refinement is explained by a mechanism where C acts as re-nucleation sites. The W film is-13 GPa hard, while the W:C films achieve a peak hardness of-24 GPa. The W:C films are-11 GPa harder than the W film, which is explained by a combination of grain refinement strengthening, solid solution strengthening and increased dislocation density. Additional micropillar compression tests showed that the flow stress increased upon C addition, from-3.8 to-8.3 GPa and no brittle fracture was observed.

Place, publisher, year, edition, pages
ElsevierElsevier BV, 2021
Keywords
Small-scale mechanical characterisation, Tungsten, PVD, Supersaturated solid solution
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-453476 (URN)10.1016/j.matdes.2021.109874 (DOI)000684858300005 ()
Funder
Swedish Research Council, 201804834Swedish Foundation for Strategic Research Swedish Research CouncilSwedish Research Council, 82120125144Swedish Research Council, 201700646_9Swedish Foundation for Strategic Research , RIF140053
Available from: 2021-09-23 Created: 2021-09-23 Last updated: 2024-01-15Bibliographically approved
von Fieandt, K., Pilloud, D., Fritze, S., Osinger, B., Pierson, J.-F. & Lewin, E. (2021). Optical and electrical properties of hard (Hf,Nb,Ti,V,Zr)N-x thin films. Vacuum, 193, Article ID 110517.
Open this publication in new window or tab >>Optical and electrical properties of hard (Hf,Nb,Ti,V,Zr)N-x thin films
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2021 (English)In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 193, article id 110517Article in journal (Refereed) Published
Abstract [en]

(Hf,Nb,Ti,V,Zr)N-x coatings with nitrogen content between 0 and 49 at.% were deposited by sputter deposition, and thoroughly characterised. Nitrogen-free coatings were found to have a bcc structure, low hardness (8 GPa), and an electrical resistivity of 144 mu Omega cm. The nitride coatings (43-49 at.% N) had NaCl-type structure, consistent with a multi-component solid solution phase. Photoelectron core level binding energies indicate that the electronic structure of the multi-component nitride differs from that of the binary nitrides, probably a result of charge transfer between the metal atoms. The nitride coatings exhibited a dense microstructure and a hardness between 29 and 33 GPa, and electrical resistivities of 141-254 mu Omega cm. They also exhibited a minimum in the optical reflectance, similar to that of TiN, indicating plasmonic properties. The position of this minimum was found to be shifted to smaller wavelengths (272-339 nm) compared to a TiN reference (428 nm) and varied with nitrogen content. The tuneability of the optical properties, in combination with the potential to influence the electronic structure through charge transfer between metal atoms point to new interesting routes to design optical materials, and a new class of optical materials based on the concept of multi-component nitrides.

Place, publisher, year, edition, pages
ElsevierPERGAMON-ELSEVIER SCIENCE LTD, 2021
Keywords
Multi-component, High entropy, Nitride, Optical properties, Mechanical properties, Sputter deposition
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-457558 (URN)10.1016/j.vacuum.2021.110517 (DOI)000703032100004 ()
Available from: 2021-11-04 Created: 2021-11-04 Last updated: 2024-01-15Bibliographically approved
Fritze, S., Hans, M., Riekehr, L., Osinger, B., Lewin, E., Schneider, J. & Jansson, U. (2020). Influence of Carbon on Microstructure and Mechanical Properties of Magnetron Sputtered TaW Coatings. Materials & design, 196, Article ID 109070.
Open this publication in new window or tab >>Influence of Carbon on Microstructure and Mechanical Properties of Magnetron Sputtered TaW Coatings
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2020 (English)In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 196, article id 109070Article in journal (Refereed) Published
Abstract [en]

(Ta,W) and (Ta,W):C films with-5 at.% C were deposited by non-reactive magnetron sputtering. They crystallised in a bcc structure with a columnar microstructure. The solid solubility of C in (Ta,W) alloys is very low, which suggests that the (Ta,W):C films are supersaturated with respect to carbon. This was confirmed by diffraction and atom probe tomography (APT) showing that carbon is in the as-deposited (Ta,W):C films homogeneously distributed in the structure without carbide formation or carbon segregation. Annealing at 900 degrees C for 2 h showed no significant column coarsening but an increased defect density at the column boundaries in the (Ta,W):C films. The films were still supersaturated with respect to carbon but APT showed a partial segregation of carbon presumably to defect-rich column boundaries after annealing. The (Ta,W) films exhibited a hardness of-12-13 GPa. Alloying with carbon increased the hardness to-17 GPa. The hardness increased to-19 GPa for the annealed (Ta,W):C films. This annealing-induced hardness increase was explained by C segregation to the more defect-rich column boundaries, which restricts dislocation movements. (Ta,W):C coatings may be a potential alternative to ceramic coatings, worth exploring further by small scale mechanical testing to investigate if these materials are ductile.

Place, publisher, year, edition, pages
Elsevier, 2020
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-404744 (URN)10.1016/j.matdes.2020.109070 (DOI)000588267900006 ()
Funder
Swedish Research Council, 2018-04834Swedish Research Council, 821-2012-5144Swedish Research Council, 2017-00646_9Swedish Foundation for Strategic Research , RIF14-0053
Available from: 2020-02-26 Created: 2020-02-26 Last updated: 2020-12-02Bibliographically approved
von Fieandt, K., Riekehr, L., Osinger, B., Fritze, S. & Lewin, E. (2020). Influence of N content on structure and mechanical properties of multi-component Al-Cr-Nb-Y-Zr based thin films by reactive magnetron sputtering. Surface & Coatings Technology, 389, Article ID 125614.
Open this publication in new window or tab >>Influence of N content on structure and mechanical properties of multi-component Al-Cr-Nb-Y-Zr based thin films by reactive magnetron sputtering
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2020 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 389, article id 125614Article in journal (Refereed) Published
Abstract [en]

Al-Cr-Nb-Y-Zr-N films have been deposited with reactive dc magnetron sputtering at various N-2 flow ratios to achieve films with different nitrogen content, from purely metallic to fully nitrided films. The structure evolved from mainly amorphous with a minor crystalline intermetallic phase for the film without nitrogen, to nanocomposites with a cubic crystalline phase in an amorphous matrix for intermediate nitrogen content (15-41 at.% N), and at higher nitrogen content (46-51 at.% N) to crystalline solid solution nitrides with a NaCl-type structure. Partial elemental segregation on the nanoscale was found in all studied samples and the films exhibited different segregation behaviour depending on the nitrogen content, implying that the structural evolution on the nanoscale of films in this material system complex and highly composition-dependent. The hardness increased with increasing nitrogen content, reaching a maximum at about 30 GPa at for the nitride films with 50 at.% N. Deformation behaviour, studied by indentation measurements, of the nitride films was found to be ductile, where no sign of crack formation could be observed. This can be attributed to a metallic phase in the columnar boundaries caused by partial elemental segregation of mainly yttrium. Hence, films within in this material system, although the nanostructure is found to be relatively complex, show very promising mechanical properties and the structural complexity can be used as a guide for designing nitride materials that combine high hardness with ductility.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2020
Keywords
High-entropy nitrides, Nitride coatings, Multi-principal element nitrides, Hardness, Crack resistance, Toughness
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-411525 (URN)10.1016/j.surfcoat.2020.125614 (DOI)000528194000054 ()
Funder
Swedish Research Council, C0514401Swedish Foundation for Strategic Research , RIF14-0053
Available from: 2020-06-04 Created: 2020-06-04 Last updated: 2020-06-04Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-5445-1374

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