Comparison of corrosion behaviors and wettability of CMAS on Ta2O5-Y2O3 co-stabilized ZrO2 and YSZ thermal barrier coatings

High-temperature degradation of the plasma sprayed 16 mol% TaO2.5 + 16 mol% YO1.5 co-stabilized ZrO2 (YTZ) and YSZ (7.6 wt% Y2O3-stabilized ZrO2) coatings under calcium-magnesium-aluminon-silicate (CMAS) attack at 1200 degrees C and 1250 degrees C were comparatively investigated. Results indicated that the coatings were insensitive to the infiltration of CMAS after 10 h corrosion at 1200 degrees C. At 1250 degrees C, the entire YSZ cross-section completely failed and also underwent serious chemical corrosion after 3 h hot corrosion. Even after 10 h corrosion, the penetration depth of CMAS into the YTZ was only about 80 & mu;m. For YTZ coating, the YTaO4 stabilizer could not easily dissolve in CMAS and precipitated out of the YTZ crystal lattice owing to the strong chemical interaction between Ta5+ and Y3+. The wettability of CMAS on YTZ coating was worse than that on YSZ coating. Compared with YSZ coating, the YTZ coating showed better resistance to CMAS corrosion.