Preparation and characterization of monolayer oxidation resistant coating on C/SiC composites

Ba0.25Sr0.75Al2Si2O8 (BSAS), Yb2SiO5 and Y2SiO5 are widely deposited as the main phase of composite coatings or as the functional layer in multilayer coatings. The investigation of monolayer coating can not only broaden the application of monolayer anti-oxidation coating, but also be an important basis for the design of multilayer and composite coatings. Monolayer BSAS, Yb2SiO5 and Y2SiO5 coatings were deposited on C/SiC composite by atmospheric plasma spraying (APS). Thermal physics and chemical properties, microstructure, bond stability and oxidation protection of the monolayer coatings were investigated. The results showed that the monolayer coating effectively improved the oxidation resistance of C/SiC composite. The microstructure and mechanical properties of the coatings play an important role in the bond stability and oxidation resistance of the coated sample. Among the tested coatings, the Y2SiO5 coating exhibited excellent mechanical properties and compact structure, which resulted in the highest bond stability and the best protection.