高纯莫来石粉体的溶胶-凝胶法制备及表征

Preparation of High Pure Mullite by Sol-gel Method and Its Characterization

以九水硝酸铝和正硅酸乙酯为原料,用溶胶-凝胶方法在pH=0.5~5.5的条件下制备莫来石前驱体凝胶,当pH=0.5时,热处理到1 100℃,保温4 h,开始出现莫来石晶相,1 150℃保温4 h,已完全莫来石化,当pH=5.5时,热处理到1 250℃才能完全莫来石化。采用XRDI、R对其莫来石化行为进行了表征,研究表明：莫来石化经历了Al-Si尖晶石的形成及与无定形SiO2的反应生成莫来石的过程。

High pure Mullite powder was prepared by sol-gel method when the pH value of precursor sol of Mullite was from 0.5 to 5.5 by taking tetraethoxysilane and aluminum nitrate as raw materials. When the pH value of precursor sol was 0.5, the precursor gel was transformed into crystalline Mullite by heat treatment at 1 100 ℃ and hold for 4 hours, and at 1 150 ℃, Mullite phase was formed completely and hold for 4 hours. Mullite phase wasn＇ t formed until 1 250 ℃ when the pH value of the sol precursor was 5.5. X-ray diffraction and IR, which indicated that transient Al-Si spinal formation, carried out the char- acterization of mullization and the amorphous SiO2 appeared in process of mullization.