CMAS corrosion resistance of Gd2O3-Yb2O3-Y2O3-stabilized ZrO2 coatings with different surface states

Thermal barrier coatings (TBCs), critical for enhancing the efficiency of aircraft engines, are susceptible to corrosion by CaO-MgO-Al ₂ O ₃ -SiO ₂ (CMAS). In this study, Gd ₂ O ₃ -Yb ₂ O ₃ -Y ₂ O ₃ -stabilized ZrO ₂ (GYYSZ) TBCs were prepared via atmospheric plasma spraying, and different surface states were obtained through mechanical grinding. The corrosion behavior of CMAS on coatings with different surface roughness was researched, and the corrosion mechanism was explained. The diffusion area of CMAS on the ground coatings surface is smaller, and the contact angle with the ground coatings is larger, compared with the coatings without mechanical polishing. Many spherical particles formed in the GYYSZ coatings after being corroded by CMAS at 1250°C, but demonstrating exceptional phase stability with retention of cubic phase throughout the 20 h exposure period. The ground coatings display fewer spherical particles than the as-sprayed coatings under the same corrosion conditions. The ground coatings manifest more residual CMAS on their surface, indicating that less CMAS penetrates into the coatings. This study suggests that the ground coatings significantly inhibit CMAS wetting and exhibit superior CMAS corrosion resistance compared to the as-sprayed coatings.