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H. Riedl, A. Vieweg, R. Rachbauer, P. Polcik, P.H. Mayrhofer:
"High temperature oxidation behaviour and mechanical properties of PVD sputtered Mo-Si-B coatings";
Talk: 14th International Conference on Plasma Surface Engineering, Garmisch-Partenkirchen; 2014-09-15 - 2014-09-19; in: "Book of Abstracts", (2014), 64.

State of the art industrial applications require increased performance and efficiency, which is in most cases linked to elevated process or combustion temperatures, even beyond 1000°C. Materials exposed to these temperatures need protective coatings, such as thermal barrier coatings (TBC), to withstand the applied mechanical and thermal load. However, typical TBCs are mostly brittle and obtain inferior mechanical properties, hence the area of use is limited. Refractory-metal-based thin films exhibit the most promising properties to overcome these requirements, due to their high melting points, thermal and mechanical properties, and electronic structure. The excellent creep resistance of Mo-Si-B bulk materials constitute them as coatings for Ni-based-superalloys for high temperature applications. Nevertheless Mo1-x-ySixBy coatings are up to now not fully understood and the knowledge on this system requires further investigations.
Within this study we investigate the mechanical and thermal properties as well as the oxidation behavior of sputter deposited Mo1-x-ySixBy thin films in the high temperature regime. Based on the ternary system and former bulk material studies we focus on compositions containing x and y ≤ 0.50, and so distinguish between 12 different Mo1-x-ySixBy coatings. We used elemental Mo, Si and B targets as well as powder metallurgical Mo-Si-B targets to reach all preferred compositions. All coatings exhibit dense and columnar structures in the as deposited state. Increasing Si and B contents lead to grain refinement, which is also confirmed through XRD analysis. Vacuum annealing at 900°C stabilizes the crystalline structures of three preferred phases Mo3Si, Mo5Si3, and Mo5SiB2. During oxidation experiments the formation of a stable SiO2 protection layer on top of the coatings after exposure to 900, 1100, and 1300°C for 1h could be observed.

Project Head Paul Heinz Mayrhofer:
Christian Doppler Labors für anwendungsorientierte Schichtentwicklung