Corrosion resistance and microstructural evolution of Y-Al-Si-O glass-ceramics environmental barrier coating candidate in the presence of CMAS

The corrosion resistance of Y₂O₃-Al₂O₃-SiO₂ (YAS) microcrystalline glass against molten calcium‑magnesium-aluminium-silicate (CMAS) attack was systematically investigated at 1350 °C. YAS microcrystalline glass, possessing an optical basicity (OB) value comparable to that of CMAS, demonstrates enhanced resistance to CMAS corrosion, with a corrosion depth of ∼70 μm following 10 h of exposure. YAS ceramics, upon corrosion, formed two distinct layers at the interface: a transition layer adjacent to the CMAS melt and a reaction layer closer to the YAS ceramic. The transition layer comprised anorthite and CMAS melt, while the reaction layer included apatite, anorthite, and a small amount of the amorphous phase. The transition and reaction layers, formed after corrosion, were extremely dense, with no cracks or other destructive defects observed. The superior CMAS corrosion resistance of YAS ceramics provides substantial theoretical support for its application as an environmental barrier coating (EBC).