Evolution behavior of rare-earth yttria modified silicide oxidation-resistant coating at 1700 °C

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 degrees 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 degrees 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.