Growth kinetics of apatite layer evolved from calcia-magnesia-aluminosilicate (CMAS) hot corrosion reaction of (Y1-xYbx)2SiO5 ceramics at elevated temperatures of 1673 K and 1773 K

Abstract

Calcia-magnesia-aluminosilicate (CMAS) corrosion behaviors of hot-pressed (Y1-xYbx)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 (Y1-xYbx)2SiO5 EBCs materials to resist CMAS corrosion.