Growth kinetics of apatite layer evolved from calcia-magnesia-aluminosilicate (CMAS) hot corrosion reaction of (Y_1-xYb_x)₂SiO₅ ceramics at elevated temperatures of 1673 K and 1773 K

Calcia-magnesia-aluminosilicate (CMAS) corrosion behaviors of hot-pressed (Y_1-xYb_x)₂SiO₅ ceramics at 1673 K and 1773 K have been investigated. The main corrosion product of nonstoichiometric Ca-RE-Si-O apatite phase evolves with increasing temperature or prolonging corrosion time. The growth of apatite layer at 1673 K follows approximately a linear rate law, however it follows a proximately parabolic rate law at 1773 K. The growth rate of the apatite layer at 1773 K is lower than that at 1673 K in the process of interaction between CMAS and rare-earth monosilicates. Yb-doping mediates the CMAS corrosion resistance of Y₂SiO₅ effectively by changing the growth rate of apatite layer and the composition of formed apatite phase. This work provides new insights on compositional regulation of (Y_1-xYb_x)₂SiO₅ EBCs materials to resist CMAS corrosion.