Hot corrosion behavior of barium aluminosilicate-coated C/SiC composites at 900°C

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°C in dry air and water vapor, respectively. The molten Na₂SO₄ was used as the corrosion reactant. The results indicate that the BAS coatings can effectively block the attack of molten Na₂SO₄ to C/SiC composites in dry air. However, the coated composites degrade rapidly when exposed to molten Na₂SO₄ coupled with water vapor. It is found that the BAS is corroded by Na₂SO₄ 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.