Abstract:With the continuous update and iteration of aviation engines, higher requirements are put forward for the hot-end components and protective materials of aviation engines. The environmental barrier coating has undergone long-term development and has formed the third-generation environmental barrier coating based on rare earth silicates, but its performance is still difficult to meet the actual engineering application requirements in the long-term CMAS corrosion environment. This work studied the influence of different heat treatment times on the microstructures and anti-CMAS corrosion properties of the Yb₂Si₂O₇- Yb₂SiO₅ composite coating at 1350°C, and analyzed the reasons for the influence of different heat treatment times on the anti-CMAS corrosion ability of the composite coating. The results show that during the heat treatment process, the volume expansion caused by the phase transformation leads the residual stress in the coating to change from tensile stress to compressive stress, which is beneficial to the healing of cracks in the coating. The corrosion product is mainly the needle-shaped apatite phase Ca₂Yb₈(SiO₄)₆O₂, and appropriate heat treatment can improve the anti-CMAS corrosion ability of the composite ceramic.