用Sol－Gel法合成莫来石超细粉机理及过程的研究

A Study of Synthesis of Fine Mullite Powder by Sol-Gel Process

以正硅酸乙酯（ＴＥＯＳ）和硝酸铝为原料，用Ｓｏｌ－Ｇｅｌ法合成了莫来石超细粉。探讨了ＴＥＯＳ在硝酸铝存在下的水解缩聚机理。并用差热一逸气、Ｘ一射线衍射、红外光谱及透射电镜等对莫来石的形成过程、结构及颗粒大小进行了研究。结果表明，参与了Ｓｏｌ－Ｇｅｌ过程，并起酸的催化作用，Ａｌ￣（３＋）也参与了网络结构。莫来石相是经过铝硅尖晶石转化成的，在１１５０℃明显生成。１２００℃尖晶石相消失，全部为莫来石，平均粒径为０．０５μｍ。

Fine mullite powder was synthesized by sol-gel process,using tetraethoxysilane(TEOS)and aluminuum ni-trate as raw materials. The mechanism of hydrolysis condensation of TEOS in the presence of aluminium nitrate was studied.The formation,structure and particle size of mullite were investigated by DTA,x-ray diffraction,infrared absorption spectra and electron microscopy.Experimental results demonstrated that participated in the Sol-Gol process giving an effect of acid catalysis,and Al￣(3+) participated in the net structure as well.Mullite was derived from aluminium-silicon spinel and formed at 1150℃ obviously,Spinel disappeared at 1200℃ and all became mullite with an average size of 0.05 μm.