Abstract: Lanthanum-cerium oxide (La₂Ce₂O₇, LC) thermal barrier coatings (TBCs) were prepared by atmospheric plasma spraying (APS). The actual composition of the as-sprayed coating is La₂Ce_1.66O_4.32, due to the volatilization of CeO₂ phase during the spray process. A little decomposition of the LC coating takes place after annealing at 1400℃ for 240h. The thermal conductivity of bulk LC material is about 0.51W/(m·K) at 1000℃, which is one fourth of that of typical bulk YSZ. The coefficient of thermal expansion (CTE) of the LC coating ranges from 10×10^-6K^-1 to 13×10^-6K^-1 at the temperature from 450℃ to 1100℃, which is relatively higher than that of the YSZ coating. Dilatometric measurements show that there is slight shrinkage in the coating till 1250℃, however, a remarkable sintering process happens cluring holding period at 1250℃. A spallation of the LC TBC occurs after 60 cycles at 1100℃ by typical delaminating cracking within the LC topcoat.

Key words: thermal barrier coatings, lanthanum-cerium oxide, plasma spraying, thermal cycling