Evolution behavior of rare-earth yttria modified silicide oxidation-resistant coating at 1700 ^oC

Yttria-modified silicide (MoSi₂-Y₂O₃) oxidation-resistant coatings with multiple Y₂O₃ contents were prepared using supersonic atmospheric plasma spraying, and the oxidation resistance was investigated at 1700 °C with static atmosphere. Experimental results indicated that the sprayed MoSi₂-Y₂O₃ coating possessed good compactness, which adhered well to the SiC transition layer. Meanwhile, the Y₂O₃ addition greatly enhanced the bonding strength of the coating, and extended its service life at 1700 °C. Wherein the MoSi₂-20 wt.%Y₂O₃ coating exhibited the highest adhesive strength and best oxidation resistance with the lowest mass loss among all the coatings. In practice, the Y₂O₃ changed the microstructures of formed oxide glass scale during oxidation, and then modified the oxidation resistance of the coating. The action mechanism of Y₂O₃ on the oxidation behavior of MoSi₂-Y₂O₃ coating was analyzed.