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T. Glechner, E. Aschauer, R Hahn, D. Holec, J. Ramm, S. Kolozsvári, H. Riedl:
"Enhancing the oxidation resistance of period VI carbides and borides: A joint theoretical and experimental study";
Poster: 47th International Conference on Metallurgical Coatings and Thin Films, ICMCTF, San Diego (USA); 2021-04-26 - 2021-04-30.

Period six transition metal carbides and borides, i.e. binaries such as WB2 and TaB2 or ternaries like W1-xTaxB2, exhibit extraordinary phase stability and mechanical properties imposing them as highly interesting coating materials for UHT applications. However, they are limited by their relatively poor oxidation resistance obtaining linear scale growth kinetics and the formation of partly volatile oxides already in the range of 0.1 to 0.2 Tm. To gain an in-depth knowledge on the scale formation of period VI ceramic coating materials in oxidative environments, we apply an ab initio guided approach (Density Functional Theory) to link initial steps of the oxidation process with experimental observations.
We used ab initio Molecular Dynamics applying VASP to model oxidation of period VI transition metal carbides and diborides at different temperatures (in the range of 400 to 1200 °C). The simulations were then compared with the formed oxides of the corresponding coating materials. The coating materials were synthesized using PVD based deposition techniques and oxidized using a DSC/TG system. Furthermore, the as deposited thin films and the formed scales were in depth analysed by HR-TEM, APT, as well as XRD.

Project Head Helmut Riedl:
CDL-SEC