CMAS resistance characteristics of LaPO4/YSZ thermal barrier coatings at 1250°C-1350°C

Calcium-magnesium-alumina-silicate (CMAS) attack is becoming a great challenge for thermal barrier coating (TBC) applications. In this study, CMAS corrosion behavior of LaPO4/YSZ TBCs prepared by air plasma spray was investigated at a temperature range of 1250 degrees C-1350 degrees C for 2 h and 10 h. The corrosion products, mainly consisted of apatite, anorthite and spinel, were independent on the corrosion temperature. At 1250 degrees C, the coating had a high resistance to CMAS infiltration due to the formation of a sealing layer; while at higher temperatures, it was vulnerable to CMAS penetration resulting from the largely decreased melt viscosity.