Phase stability, microstructural and thermo-physical properties of BaLn_2Ti_3O_(10) (Ln=Nd and Sm) ceramics

摘要

The phase stability, microstructural evaluation and thermo-physical properties of BaLn_2Ti_3O_(10) (BLnT, Ln=Nd and Sm) ceramics for thermal barrier coating (TBCs) application have been investigated. BLnT (Ln=Nd and Sm) powders is found thermally stable at 1500℃ after exposure for 110 h, and the bulk materials exhibit lamellar structure. BLnT (Ln=Nd and Sm) bulk materials show anisotropy in thermo-physical properties due to the insertion of Ba atoms between [Ln_2Ti_3O_(10)] (Ln=Nd and Sm) sheets. The thermal conductivities of BLnT (Ln=Nd and Sm) are apparently lower than those of ZrO_2-8Y_2O_3 (8YSZ). Also, BaSm_2Ti_3O_(10) exhibits relatively lower thermal conductivity as compared to BaNd_2Ti_3O_(10). The thermal expansion coefficient (TEC) of BLnT (Ln=Nd and Sm) is found comparable to that of 8YSZ. BaNd_2Ti_3O_(10) exhibits relatively larger TEC than BaSm_2Ti_3O_(10)- The above results suggest that BLnT (Ln=Nd and Sm) ceramics could be a good potential material for TBC applications.