摘要
本文采用DTA,XRD,SAXS,XPS,SEM,Raman等测试手段研究了MgOAl_2O_3-SiO_2-TiO_2系统玻璃在580～820℃温度范围内热处理过程中分相和晶核析出的过程.在低于玻璃转变点的温度下热处理的样品中,两相分离获得了显著的发展,分相形貌发生了很大的变化,镁铝钛酸盐晶核的形成业已开始,甚至晶核形成速率的极大值也出现在低于玻璃转变点的温度上.而且,晶核形成速率呈极大值的温度随热处理时间的延长向低温侧移动. 玻璃的分相形貌对晶核的析出与成长有很大的影响,低粘度相的惯性半径越大对以低粘度相为母相的结晶核的形成越有利,镁铝钛酸盐结晶粒子的大小和数目也与玻璃中两相分离的状态密切相关.
Phase separation and nucleation processes in MgO-Al_2O_3-SiO_2 glass containing TiO_2 during heat-treatment at a temperature in the range 580～820℃ were investigated by several methods including DTA, XRD, SAXS, XPS, SEM and RAMAN.It was found that in the glass heat-treated at a temperature lower than its glass transition temperature (T_g), the phase separation proceeded and the morphology of the phase separation changed greatly, that the largest value of the nucleation rate occured at a temperature lower than T_g and that the temperatures of maximum nucleation rate became lower with the extension of the heat-treatment time.It was also discovered that the morphology of the phase separation had a great influence upon nucleation and growth of Mg-Al-Titanate crystals in the glass, that the larger the radius of gyration of the lower viscosity phase (TiO_2-rich) in the glass, the better the nucleation and that the number and the size of Mg-Al-Titanate crystal particles was also influenced by the phase separation of the glass.
关键词
玻璃
分相
晶核
含TiO2
形成
phase separation
nucleation
MgO-Al_2O_3-SiO_2-TiO_2 glass
