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采用沉淀结合渗析的方法,以钨酸钠、钨酸铵为原料,制备了不同形貌、具有择优取向的MxWO3·xH2O(M=Na+,NH4+,x<1)粉晶,利用SEM、XRD、TG、IR、XPS等手段对粉体进行表征,考察了不同渗析时间和焙烧温度对粉晶形貌、晶化程度及结构转变的影响。结果表明,长时间渗析后粉体的晶化程度明显提高,并沿(010)晶面方向择优生长,形貌由不规则形变为梭形和蝴蝶形。经空气气氛400℃焙烧后,NaxWO3·xH2O和(NH4)xWO3·xH2O粉晶均转变为沿(200)晶面方向择优生长的立方青铜相,且形貌也发生改变。
MxWO3 · xH2O (M = Na +, NH4 +, x <1) powder with different morphologies and preferred orientation were prepared by precipitation and dialysis. Sodium tungstate and ammonium tungstate were used as raw materials. TG, IR, XPS and other means to characterize the powder, investigated the different dialysis time and calcination temperature on the morphology, degree of crystallization and structural transformation. The results show that the degree of crystallization of the powder increases obviously after long time dialysis, and grows preferentially along the (010) plane. The morphology changes from irregular to fusiform and butterfly. After firing in air at 400 ℃, the powders of NaxWO3 · xH2O and (NH4) xWO3 · xH2O all transform into the cubic bronze phase which preferentially grows in the direction of (200) plane and the morphology changes.