以氧化锆和氧化镧为反应原料, 以氯化钾-氯化锂为熔盐介质, 采用熔盐法制备了烧绿石结构锆酸镧(La2Zr2O7)粉体, 研究了反应温度和熔盐含量对该粉体纯度的影响, 并分析了其显微结构。结果表明:La2Zr2O7粉体除了由原料直接反应合成外, 还有部分是由La2O3与熔盐先生成中间产物LaOCl, 该中间产物再与ZrO2反应而生成; La2Zr2O7相的生成量随反应温度的升高而增加, 随熔盐含量的增加先增后减; 当熔盐与反应原料的质量比为3∶1时, 在1 200 ℃下反应3 h后可以合成纯La2Zr2O7相的粉体, 其形貌与原料ZrO2粉体的基本相似, 呈无规则颗粒状, 晶粒大小为80～200 nm。

The La2Zr2O7 powders with pyrochlore structure were synthesized by the molten salt method with zirconium oxide and lanthanum oxide as reaction materials and with potassium chloride and lithium chloride as reaction media. The influences of reaction temperatures and molten salt content on the powder purity were investigated and the microstructures of the prepared powders was analyzed. The results show that apart from that directly prepared by the reaction materials, the La2Zr2O7 powders were also synthesized by the reaction of ZrO2 powder with intermediate product of LaOCl produced by the reaction of La2O3 powder with molten salts. The production of La2Zr2O7 phase increased with the increase of the reaction temperature and first increased then decreased with the molten salt content increase. Pure La2Zr2O7 powder was obtained under the condition of reaction at 1 200 ℃ for 3 h with the mass ratio of molten salt to reaction material of 3∶1. The morphology of the prepared La2Zr2O7 powder was similar to that of raw material ZrO2 powder, showing an irregular particle shape with grain sizes of 80-200 nm.