(La_(0.75)Sm_(0.25))_2Zr_2O_7纳米粉体的高温动态XRD研究

High temperature dynamic XRD research of (La_(0.75)Sm_(0.25))_2Zr_2O_7 nano powder

采用化学共沉淀-高温煅烧技术制备的具有烧绿石结构的(La0.75Sm0.25)2Zr2O7纳米粉体,其平均晶粒尺寸约为47 nm,其晶体结构为等轴晶系,空间群为F d-3m,晶胞参数a0=1.075 nm。采用高温动态XRD技术研究了(La0.75Sm0.25)2Zr2O7纳米粉体的热稳定性、热膨胀性及抗烧结性能。结果表明:(La0.75Sm0.25)2Zr2O7纳米粉体具有良好的热稳定性,高温下晶体结构仍保持稳定,1 400℃的热膨胀系数为9.7×10-6K-1;具有优异的抗高温烧结性能,1 250℃以上纳米晶粒才开始快速生长,1 400℃时,晶粒尺寸为132 nm。

（ La0.75 Sm0.25 ）2Zr2O7 nano powders with pyrochlore structure were prepared by chemical co-dep- osition-high temperature calcination method. The average grain size of the powders is about 47 nm. The crystal structure is cubic system;space group is F d-3m;cell parameter ao = 1. 075 nm. The thermal stabili- ty,thermal expansion and sintering resistance of the powders were investigated by high temperature dy- namic XRD. The results show that the （ La0.75 Sm0.25 ）2Zr2O7 nano powders exhibit a good thermal stability with a stable crystal structure at high temperatures,and a thermal expansion coefficient of 9.7×10^6K^-1 at 1 400 ℃;the powders display an excellent sintering resistance at high temperatures; nanocrystals begin to grow rapidly at 1 250 ℃ above,and the grain size is 132 nm at 1 400 ℃.