Hot Corrosion Behavior of Barium Aluminosilicate-Coated C/SiC Composites at 900℃

摘要

Barium aluminosilicates (BAS) were coated on the carbon fiber-reinforced silicon carbide composites (C/SiC) as environmental barriers. The hot corrosion behavior of the coated composites was studied at 900℃ in dry air and water vapor, respectively. The molten Na_2SO_4 was used as the corrosion reactant. The results indicate that the BAS coatings can effectively block the attack of molten Na_2SO_4 to C/SiC composites in dry air. However, the coated composites degrade rapidly when exposed to molten Na_2SO_4 coupled with water vapor. It is found that the BAS is corroded by Na_2SO_4 melt with the formation of BaSO_4, resulting in the destruction of BAS structure, which makes the coating lose its protection to the C/SiC composites in water vapor.