具有不同形貌和择优取向的M_xWO_3·xH_2O粉晶的制备与表征

Preparation and Characterization of Oriented M_xWO_3·xH_2O Crystallite with Different Morphologies

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·xH20 crystallite with different morphologies and preferential orientation was obtained using Na2WO4·2H20 and （NH4）10W12O41 as the starting materials by precipitation and dialysis methods. The effects of dialyzing time and sintering temperature on morphologies, crystallinity and structure of the powders were investigated by SEM, XRD, TG, IR and XPS technology. The results show that the crystallite has good crystallinity with preferential orientation along （010） plane and the morphology changes from irregularity to shuttle plate or butterfly shape during long dialyzing time. The cubic tungsten bronzes with （200） preferential orientation were formed when both products were sintered at 400 ℃ in air for 4 h. And the morphologies changed to quasi-spherical shape and partial particles destroyed after NaxWO3·xH20 and （NH4）xWO3·xH20 being sintered, respectively.