Characterization of microstructure and oxidation resistance of Y and Ge modified silicide coating on Nb-Si based alloy

•Ge and Y modified silicide coating on Nb based in situ composites was prepared.•The addition of Y can refine the grain size.•The good oxidation resistance is due to the rapid formation of protective oxide scale.

Y and Ge modified silicide coating was prepared on the Nb-Si based alloy by Si–Ge–Y co-deposition at 1300 °C for 10 h. It is observed that the coating is composed of an outer layer and a transitional layer. The mass gain of Si–Ge–Y coating is 2.78 mg cm−2 after oxidation at 1250 °C for 100 h. The results indicate that Y refines grains, which can promote the rapid formation of protective SiO2 and GeO2 scale. Therefore, the oxidation resistance of the coating is improved.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideThe Si–Ge–Y coating has the less mass gain and thinner oxide scale after oxidation at 1250 °C for 100 h compared with the Si–Ge coating, indicating that the Si–Ge–Y coating shows better oxidation resistance than the Si–Ge coating.