Lanthanum-cerium Oxide Thermal Barrier Coatings Prepared by Atmospheric Plasma Spraying

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 La2Ce1.66O4.32, due to the volatilization of CeO2 phase during the spray process. A little decomposition of the LC coating takes place after annealing at 1400 or 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 0-6K-1 to 13 0-6K-1 at the temperature from 450 o 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 y typical delaminating cracking within the LC topcoat.