Effect of vacancy on thermal expansion coefficient of Sm₂Zr₂O₇ ceramic

M_0.1Sm_1.9Zr₂O_6.95 ceramics were synthesized by solid phase reaction using ZrO₂ powder, Sm₂O₃ powder and bivalent MO powder (M=Mg, Ca) as starting materials. The compacts made from the mixed powders were sintered into bulks at the temperature of 1600°C for 10 hours in air. The phases of the synthesized bulks were identified by X-ray diffraction (XRD) and the microstructure of the bulks was examined by SEM. The thermal expansion coefficients of the bulks were measured by thermal dilatometer. The results show that M_0.1Sm_1.9Zr₂O_6.95 ceramics with single phase and uniform microstructure were prepared successfully. The thermal expansion coefficient of M_0.1Sm_1.9Zr₂O_6.95 ceramic is higher than that of pure Sm₂Zr₂O₇ ceramic due to the introduction of vacancy. The improvement of the thermal expansion coefficient of the ceramic material for thermal barrier coatings is beneficial to the increasing of the service life of coatings.