中文摘要：

以六水合硝酸镧为原料,尿素为沉淀剂,采用均匀沉淀法制备了La2O3纳米晶,探讨了制备条件对产品产率和平均粒径的影响,得出了最佳工艺条件：反应物n（尿素）/n（硝酸镧）为6∶1,沉淀反应温度和时间分别为115℃和2.0h,煅烧温度为750℃。同时,利用FT-IR、XRD和SEM等分析方法对最佳制备条件下所得产品的物相结构、形貌和粒径进行了表征。结果显示：实验制备的La2O3纳米晶颗粒呈球形,分散性好,纯度较高,属六方晶系结构,平均粒径为32 nm。

英文摘要：

Nanoerystalline La2O3 were prepared by homogeneous precipitation method using urea as precipitant and La（NO3）3 ·6H2O as raw materials. The influences of various processing parameters in preparation process on the yield and mean size of the products were investigated. The optimum conditions for preparing nanocrystalline La2O3 are as follows： the molar ratio of urea to lanthanum nitrate hexahydrate is 6： 1, the temperature of precipitation reaction is 115 ℃, the reaction time is 2.0 h, and the calcination temperature is 750 ℃. FT-IR, XRD and SEM were used to characterize the crystalline structure, morphology and size of nanocystalline. The results indicate that nanocystalline La2O3 prepared at the optimum conditions are spherical in shape and well dispersed; they have high purity and a fine crystal phase of hexagonal syngony structure with a mean size of 32 nm.