氧化铝-莫来石复合粉对莫来石烧结行为的影响

Effect of alumina-mullite composite powder on mullite sintering behavior

将莫来石先驱体溶胶预先引入到硫酸铝水溶液中 ,干燥后经 12 0 0℃煅烧获得氧化铝 -莫来石复合粉料。研究了该粉料与硅溶胶混合获得的混合粉的烧结行为 ,并与氧化铝、莫来石晶种和硅溶胶三相混合获得的混合粉的烧结行为进行了分析比较。其中 ,两种混合粉料均是以理论莫来石组分进行配比 (Al2 O3∶SiO2 =72∶2 8) ,并且两种混合粉中莫来石晶种的质量分数均为 5%。实验结果表明 :前者在 1450℃烧结 2 0min即实现完全莫来石化 ,其显微结构为晶须状莫来石 ;后者在 150 0℃烧结 2 0min实现完全莫来石化 。

Alumina-mullite composite powder was synthesized by drying and calcining the mixture solution at 1200 ℃,which was prepared by mixing aluminium sulfate aqueous solution and mullite precursor sol.The sintering behaviors of one mixture prepared by mixing alumina-mullite composite powder and silica sol and another mixture prepared by mixing the alumina powder,mullite seeds powder and silica sol were studied and compared.The two mixtures have the same ratio as stoichiometric mullite composition(Al 2O 3∶SiO 2=72∶28) and the same mullite seeds content (5%).XRD analysis results indicate that the mullitization temperatures of the two mixtures were 1450 ℃ and 1500 ℃ respectively.The SEM photographs display the two mullites formed at 1450 ℃ and 1500 ℃ for 20 min were whisker like and needle like respectively.