A5041013473- Metal and Thin Film Mechanics
- MXene and MAX Phase Materials
- Semiconductor materials and devices
- Advanced ceramic materials synthesis
- Intermetallics and Advanced Alloy Properties
- Aluminum Alloys Composites Properties
- Metallurgical Processes and Thermodynamics
- Boron and Carbon Nanomaterials Research
- Diamond and Carbon-based Materials Research
- Advanced materials and composites
- Advanced Materials Characterization Techniques
- High-Temperature Coating Behaviors
- Iron and Steelmaking Processes
- Chemical Looping and Thermochemical Processes
- nanoparticles nucleation surface interactions
- Thermal and Kinetic Analysis
- Metallurgical and Alloy Processes
- Copper Interconnects and Reliability
- Metal Extraction and Bioleaching
- Metallic Glasses and Amorphous Alloys
- Manufacturing Process and Optimization
- 2D Materials and Applications
- Machine Learning in Materials Science
- Semiconductor materials and interfaces
- Electronic and Structural Properties of Oxides
GTT-Technologies (Germany)
2016-2025
Uppsala University
2020
RWTH Aachen University
2009-2017
University of California, Los Angeles
2016
The phase stability of Al-containing cubic transition metal (TM) nitrides, where Al substitutes for TM (i.e. 1− x N), is studied as a function the valence electron concentration (VEC). X-ray diffraction and thermal analyses data magnetron sputtered Ti N, V N Cr films indicate increasing at larger contents higher temperatures with VEC. These experimental findings can be understood based on first principle investigations ternary = Sc, Ti, V, Cr, Y, Zr Nb VEC lattice strain are systematically...
Extreme cooling rates during physical vapor deposition (PVD) allow growth of metastable phases. However, we propose that reactive PVD processes can be described by a gas–solid paraequilibrium defining chemical composition and thus point defect concentration. We show this notion allows for engineering controlling conditions. As example demonstrate thermal stability (Ti,Al)Nx, the industrial benchmark coating wear protection, increased from 800°C to unprecedented 1200°C minimizing vacancy The...
The solubility of zirconium (Zr) in the Nb4AlC3 host lattice was investigated by combining experimental synthesis (Nbx, Zr1-x)4AlC3 solid solutions with density functional theory calculations. High-purity were prepared reactive hot pressing NbH0.89, ZrH2, Al, and C starting powder mixtures. crystal structure produced determined using X-ray neutron diffraction. limited Zr (maximum 18.5% Nb content lattice) observed experimentally is consistent calculated minimum energy mixing. parameters...
Ti-Al-O-N coatings were synthesized by cathodic arc and high power pulsed magnetron sputtering. The chemical composition of the was determined means elastic recoil detection analysis energy dispersive X-ray spectroscopy. effect oxygen incorporation on stress-free lattice parameters Young's moduli investigated diffraction nanoindentation, respectively. As nitrogen is substituted oxygen, implications for charge balance may be expected. A reduction in equilibrium volume with increasing O...
In this work the electronic structure and mechanical properties of phases X2BC with X =Ti, V, Zr, Nb, Mo, Hf, Ta, W (Mo2BC-prototype) were studied using ab initio calculations. As valence electron concentration (VEC) per atom is increased by substitution transition metal X, six very strong bonds between carbon shift to lower energies relative Fermi level, thereby increasing bulk modulus values up 350 GPa, which corresponds 93% value reported for c-BN. Systems higher VEC appear be ductile as...
To identify the origin of experimentally observed nitrogen over- and understoichiometry in TiAlN thin films, various point defect configurations were studied by ab initio calculations terms formation energies, equilibrium volume elastic moduli. From energies comparison to existing experimental elasticity data, it is shown that vacancies metal are responsible for overstoichiometry, respectively. Irrespective type vacancies, bulk modulus decreased approximately 7% as concentration increased or 3 at.%.
LaCr 1− x Co O 3 solid‐solution ceramics ( = 0.0–0.3) were prepared by pressureless sintering of a submicrometer powder. The powder was synthesized modified glycine nitrate process at 800°C. electrical conductivity the material sintered 1600°C measured AC four‐wire method from room temperature to 1200°C. While undoped 0) LaCrO revealed semiconductivity dominated thermally activated mobility small polarons over vast range, substitution for Cr gave rise pronounced enhancement temperatures...
The influence of oxygen concentration on the structure and mechanical properties V0.5Al0.5OxN1−x thin films (0 ≤ x 0.8) was investigated. unexpected experimental lattice parameter decrease with increasing can be understood based ab initio data: incorporation induced formation metal vacancies reduces equilibrium volume stabilizes metastable solid solutions. Charge balancing is identified as underlying physical mechanism by Bader decomposition analysis. Hence, property predictions for these...
It is shown that the investigated TiAlN and TiAlNO protective coatings show an enrichment of oxygen in surface near region with concurrently higher oxidation states titanium. We suggest caused by reaction atmospheric at room temperature and/or residual gas immediately after deposition during cooling chamber. As this coating system used cutting forming operations, here-established difference between composition great relevance for understanding interactions thereof materials to be cut or formed.
A method to model the metastable phase formation in Cu-W system based on critical surface diffusion distance has been developed. The driver for of a second is which dependent solubility W Cu and W. Based comparative theoretical experimental data, we can describe relationship between solubilities distances order formation. Metastable diagrams Cu-V thin films are predicted validated by combinatorial magnetron sputtering experiments. correlative research strategy adopted here enables us...
We assess the concept of alchemical transformations for predicting how a further and not-tested change in composition would materials properties. This might help to guide ab initio calculations through multidimensional property-composition spaces. Equilibrium volumes, bulk moduli, relative lattice stability fcc bcc 4d transition metals Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag are calculated using density functional theory. Alchemical derivatives predict qualitative trends while equilibrium volumes...
Hafnium oxynitride films are deposited from a Hf target employing direct current magnetron sputtering in an Ar–O2–N2 atmosphere. It is shown that the presence of N2 allows for stabilization transition zone between metallic and compound mode enabling deposition at well defined conditions coverage by varying O2 partial pressure. Plasma analysis reveals this experimental strategy facilitates control over flux O− ions which generated on oxidized surface accelerated negative potential toward...
The impact of oxygen additions on phase stability and elastic properties titanium aluminum nitride is studied by ab initio calculations. Fcc-Ti0.5Al0.5N fcc-Ti0.5Al0.5O show a negative energy mixing with an interaction parameter ΩTiAlNO −37.6 kJ mol−1. lattice Ti0.5Al0.5N1−xOx increases increasing x while the bulk modulus decreases 35%. reason metallic bonding character which at expense covalent content. It shown that incorporation in interstitial sites energetically favourable. This can be...