摘要
深刻理解莫来石的形成及其动力学对采用反应烧结方法制备具有良好性能的莫来石或含莫来石陶瓷具有重要的指导意义。本文对几种含Al2 O3 SiO2 体系反应烧结过程中莫来石的形成过程进行了系统总结 ,深入分析了莫来石形成及其动力学机制的影响因素。表明莫来石的形成机制主要取决于反应温度和起始原料的特征 ,低温下 (<165 0℃ )莫来石形成是一个在富SiO2 基质中成核和生长的过程 ,其生长速率受Al2 O3颗粒向非晶富SiO2 基质相中的溶解过程控制 ;而在 165 0℃以上 ,莫来石的成核和生长发生在Al2 O3和SiO2 的界面上 ,生长速率由Al3+ 和Si4 +
The literatures in the past decades,with respect to mullite formation by reaction sintering of Al 2O 3/SiO 2 containing mixed powders,were reviewed in this paper,and the factors affecting mullite formation mechanism were discussed.It is indicated that the nucleation and growth of mullite is closely related to reaction temperature and properties of starting materials.At low temperature,mullite formation occurs by nucleation and growth within the aluminosilicate phase formed by reaction between Al 2O 3 and SiO 2,and the growth rate is controlled by the dissolution of Al 2O 3.At high temperature,however,mullite will nucleate and grow at the point of contact between Al 2O 3 and SiO 2 particles,and the rate-controlling step is the diffusion of Al 3+ and Si 4+ through mullite crystal lattice.A crossover temperature,at which mullite formation mechanism begin to tranform,is suggested to be between 1350℃ and 1650℃.
出处
《陶瓷学报》
CAS
2002年第3期149-155,共7页
Journal of Ceramics
