络合溶胶-凝胶法制备不同形貌的莫来石微晶

Preparation of Mullite Microcrystallites with Different Morphology by Complexing Sol-gel Method

采用溶胶-凝胶法,以Al(NO3)3.9H2O、正硅酸乙酯(TEOS)为主要原料,分别以草酸、柠檬酸和乙二胺四乙酸钠为络合剂,合成了具有不同微观形貌的莫来石粉体。并运用差热分析(DTA)、X射线衍射(XRD)、红外傅里叶变换分析仪(FTIR)、EDS能谱及扫描电子显微镜(SEM)等对制备的莫来石粉体的物相、形貌和元素组成进行了表征。结果表明:莫来石的开始合成温度在1046℃左右,而实际后处理温度要达到1300℃才能得到结晶良好且为单一物相的莫来石粉体。通过添加不同络合剂,经过煅烧,均得到了物相单一,形貌分别为棒状、棒簇状和花纹状莫来石微晶。

Mullite powders were prepared by sol-gel process using TEOS and Al（NO3）3·9H2O as raw materials.Mullite with varied morphology were produced by adding different complexing agent such as oxalic acid,citric acid and ethylene diamine tetraacetic acid（EDTA） in the reaction.The phase composition,morphologies and element distribution of the as-prepared powders were characterized by differential thermal analysis（DTA）,X-ray diffraction（XRD）,FTIR Spectrometer（FTIR）,energy dispersive spectroscopy（EDS） and scanning electron microscope（SEM）.The results show that the initial temperature of the mullitization of gels is about 1046 ℃,but the temperature of pure mullite should be at 1300 ℃.Mullite powders with morphologies of grain-like,rod-like,cluster-like and flower-like could be prepared by adding different complexing agent.