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H. Ömer:
"Oxidation behavior of Si alloyed transition metal diborides";
Supervisor: H. Riedl, T. Glechner; E308, 2021; final examination: 2021-03-24.

Ultra-high-temperature ceramics are materials, that are known for their high hardness, Young´s moduli and melting points. Though this group consists of borides, nitrides, carbides and oxides of early transition metals, a special focus in research has been set on borides. However, the very promising group of transition metal diborides lacks in oxidation resistance when being exposed to elevated temperatures, therefore limiting its possible applications. Current research has shown that the alloying of bulk borides with silicon can improve the oxidation behavior by enabling the formation of silica scales.

The aim of this study is to further investigate silicon´s influence on the oxide scale formation of transition metal diboride coatings. Since the focus of previous research was mainly set on bulk hafnium- and zirconium-based borides, the effect of silicon will also be investigated on several other diboride coatings.

At first, thin films of transition metal diborides with varying silicon contents, produced on a lab scale vapor deposition system, will be investigated concerning their mechanical properties, structure, chemical composition, and oxidation behavior. Following this initial process, samples coated on an industrial deposition system will also be examined. After acquiring the desired data, the study´s results will be reviewed and interpreted.

Project Head Helmut Riedl:
CDL-SEC