JIANG Weihui, PENG Yongfeng, LIU Jianmin, FENG Guo, MIAO Lifeng, WU Qian, ZHANG Quan

( Key Laboratory of Advanced Ceramic Materials of Jiangxi Province, School of Materials Science and Engineering,

Jingdezhen Ceramic Institute, Jingdezhen, Jiangxi 333001)

Abstract: Mullite powder has been synthesized at low temperature via non-hydrolytic sol-gel method using anhydrous aluminium chloride and ethyl silicate as precursors, and ether as oxygen donors. The effect of reflux gelation process, addition order and quantities of oxygen donors on the synthesis of mullite powder were studied; the phase transformation of mullite xerogels during the heat treatment and the reaction mechanism of low temperature synthesis of mullite via non-hydrolytic sol-gel method were also investigated by means of FT -IR, DTA -TG, XRD, TEM, etc. The results indicate that reflux gelation process is favorable for the synthesis of mullite. When oxygen donor is introduced into the AlCl₃-TEOS mixture solution, the better synthesis effect happens, and the optimal quantity of oxygen donor is 0.52L/1mol TEOS. The mullite xerogel, prepared using ether as oxygen donor through the reflux process, belongs to single-phase gel. Mullite crystal phase has begun to appear at 800℃, and well-developed at 900℃. The formation of bond during the sol-gel reaction process plays the key role in the low temperature synthesis of high purity mullite powder.

Key words  non-hydrolytic sol-gel method; mullite powder; low temperature synthesis