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.

Figure optionsDownload 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.