液相法制取Y_2(WO_4)_3的工艺探讨及其负热膨胀性能比较

Synthesis and Thermal Expansion Behavior of Y_2(WO_4)_3 by Liquid co-Precipitation

采用液相共沉淀法成功合成Y2(WO4)3,利用高、低温X射线衍射方法研究Y2(WO4)3的结构及其负热膨胀性能,发现液相共沉淀法制得的Y2(WO4)3与固相反应法制得的Y2(WO4)3具有一致的Pnca空间群正交结构和相差不大的晶胞参数和体积(经TOPAS软件计算),二者的本征体热膨胀系数分别为-18.8×10-6℃-1(液相法)和-19.5×10-6℃-1(固相法)。液相共沉淀法相对传统固相化学反应法,具有减少合成循环次数和降低反应温度的优点。这证明该法制备稀土钨酸盐类负膨胀材料是可行的。

The Y2（WO4）3 was successfully synthesized by liquid co-precipitation.The crystal structural and negative thermal expansion properties of Y2（WO4）3 were investigated with X-ray diffraction at high temperature and room temperature.The sample was found to crystallize in single orthorhombic structure with space group Pnca by XRD pattern analysis,and the values of unit cell parameters and volumes were calculated by software TOPAS,which was similar with the structure of Y2（WO4）3 synthesized by solid-state reaction.The overall volume thermal expansion coefficients of Y2（WO4）3 were calculated to be-18.8×10-6 ℃-1（for liquid co-precipitation） and-19.5×10-6 ℃-1（for solid-state reaction） respectively.The liquid phase co-precipitation reduced the synthesis cycle and sintering temperature,comparing to the conventional solid-state reaction.This indicated that the approach preparation of Tungsten salts with negative thermal expansion was feasible.