Calcium-magnesium-alumina-silicate (CMAS) resistance property of BaLn2Ti3O10 (Ln=La, Nd) for thermal barrier coating applications

Calcium-magnesium-alumina-silicate (CMAS) has posed enormous threat to thermal barrier coatings (TBCs). In this study, a series of newly developed TBC ceramics, BaLn(2)Ti(3)O(10) (Ln=La, Nd), are found to have high resistance to the penetration of molten CMAS at 1250 degrees C. The formation of a continuous, dense crystalline layer, mainly composed of apatite and CaTiO3 phases, on the sample surfaces contributed to this desirable attribute. The accumulation of Ba in the molten CMAS triggered the crystallization of the melt, leading to the formation of many BaAl2Si2O8 celsian crystals above the crystalline layer, which could reduce the mobility of the molten CMAS. The mechanisms by which the CMAS attacks BaLn(2)Ti(3)O(10) samples are discussed. The results indicate that Ba is an effective element for altering CMAS composition, and doping Ba in TBCs might be an attractive way of mitigating CMAS attack.