Synthesis and Characterization of LaMgAl_(11)O_(19) as Thermal Barrier Coatings Material

摘要

LaMgAl_(11)O_(19) was synthesized at 1550°C using La_2O_3, MgO and Al_2O_3 as raw materials. The samples were characterization by XRD and SEM. The tablet shaped crystals free of impurity phase formed under this condition. The thermal diffusivities were measured by laser flash method and the determined intrinsic thermal conductivities decreased as temperature increases from 25°C to 1000°C. As comparison, intrinsic thermal conductivities of LaMgAl_(11)O_(19) are lower than that of 7YSZ. The synthesized LaMgAl_(11)O_(19) was heat treated at higher temperature from 1600°C to 1700°C and no change in the phase indicates that the LaMgAl_(11)O_(19) phase is stable under 1700°C, which is very important for thermal barrier coatings (TBCs) serving at elevated temperature.