Oxidation-resistance of ZrB_2-MoSi_2 Composite Coatings Prepared by Atmospheric Plasma Spraying

Agglomerated ZrB2-MoSi2 composite powders with different contents of MoSi2 were successfully prepared by spray drying and vacuum sintering. Then ZrB2-MoSi2 composite coatings were deposited on C/C composites by atmospheric plasma spraying(APS) using ZrB2-MoSi2 composite powders with average size of 30 μm as raw material. The microstructure and anti-oxidation performance of coatings were characterized by XRD, SEM, etc. It could be found out that the microstructure of ZrB2-MoSi2 composite coatings was dense with bonding strength up to 7.2 MPa. And oxidation-resistance of composite coating at high temperature could be improved by appropriate addition of MoSi2. The weight loss of C/C composites coated by ZrB2-40wt%MoSi2 coating was only 1.7% after 9 h in air at 1500℃. The coating exhibited good self-sealing performance and excellent anti-oxidation ability.