Effect of MgO doping on densification and grain growth behavior of Gd_2Zr_2O_7 ceramics by microwave sintering process

摘要

In our study, the effect of MgO doping on the densification and grain growth in gadolinium zirconate (Gd2Zr2O7) during microwave sintering was reported, and the nanocrystalline Gd2Zr2O7 and Mg-doped Gd2Zr2O7 raw powders used for shaping and sintering were synthesized by a novel co-precipitation assisted solvothermal method. The results indicate that the increase in density is always accompanied by grain size growth with different degrees at different sintering temperatures (1200 degrees C, 1250 degrees C, and 1300 degrees C). The relative density increased rapidly along with the prompt grain growth at 1300 degrees C. However, when sintered at 1200 degrees C and 1250 degrees C, the grain size increased slowly, while the density increased remarkably with the further addition of MgO. Gd2Zr2O7 ceramics with high density (95%) and relatively small grain size (106nm) were fabricated at a MgO-doping amount of 2 at% and sintering temperature at 1250 degrees C. MgO was proved as an effective sintering additive for Gd2Zr2O7 which can significantly promote the densification process and also can furtherly reduce the densification temperature.