Formation and oxidation resistance of MoSi₂ coating for Nb-Si based alloy prepared by slurry sintering method

The high-temperature oxidation resistant MoSi₂ intermetallic coatings have been successfully prepared on the Nb-Si based alloy by slurry sintering method. The heating rate before the sintering temperature is reached has an obvious influence on the density and interface structure of the coatings. The coating prepared at a heating rate of 10 °C/min is the densest, with a porosity about 18.4 area%, and has a good adhesion strength of 22.5 MPa. After oxidation at 1250 ℃ for 10 h, the coating exhibits multi-layer structure consisted of an SiO₂ scale, an MoSi₂ layer, an inner oxidation layer and an (Nb,X)₅Si₃ transitional layer from the outer to the inner.