CaO–MgO–Al2O3–SiO2 (CMAS) corrosion behaviour of LaMgAl11O19/GdPO4 thermal barrier coating materials

Abstract

CaO–MgO–Al2O3–SiO2 (CMAS) corrosion poses serious hidden dangers for the application of thermal barrier coatings (TBCs). In this study, LaMgAl11O19 (LMA) and GdPO4 were mixed at molar ratios of 2:1, 1:1 and 1:2 to prepare LMA/GdPO4 materials, and the CMAS corrosion behaviours of these materials were investigated at 1300°C–1500 °C for 20 h and 40 h. It was demonstrated that temperature was the main factor influencing the corrosion behaviours and products. The materials were damaged at 1300 °C by the crystallization of CMAS melts to form CaAl2Si2O8. In contrast, the materials were corroded by CMAS melts via the reaction between CMAS and GdPO4 at 1500 °C. These results indicate that the addition of GdPO4 to LMA can improve the resistance of the LMA material to CMAS corrosion.