Hf微量掺杂Sm_2Ce_2O_7固溶体制备及热物理性能

Preparation and Thermophyscial Properties of Minor-Hf Doped Sm_2Ce_2O_7 Solid Solutions

采用高温固相烧结法制备了Sm2(Ce1-xHfx)2O7(x=0,0.025,0.05,0.075,0.1)固溶体,并对其相组成、显微组织及热物理性能进行了分析。结果表明,所合成的固溶体具有单一的萤石结构,其相对致密度均在90%以上。Hf掺杂增强了声子的散射程度,从而使其热导率与Sm2Ce2O7相比明显降低。Hf较小的离子半径使得其热膨胀系数随HfO2掺杂量增加而降低,但仍然满足热障涂层的要求。

The Sm2(Ce1-xHfx)207(x=0,0.025,0.05,0.075,0.1)solid solutions were prepared by solid state reaction at high-temperature.Their phase composition,microstructure and thermophysical properties were investigated.Results show that the synthesized ceramics have single fluorite-type structure,and their relative densities are higher than 90%.Due to the enhanced phonon scattering by Hf-doping,the thermal conductivity of the solid solutions were reduced as compared to Sm2Ce207.The thermal expansion coefficient of the prepared solid solutions decrease with increasing Hf02 contents,which can be contributed to the low ion-radius of Hf4+.The thermophyscial properties of the solid solutions can be used candidates for thermal barrier coatings.