组成对MgO-Al2O3-SiO2系统分相析晶的影响

对MgO-Al2O3-SiO2系统的分相与析晶进行了探讨,通过对不同组成点在热处理各阶段的试样进行XRD、TEM及DTA分析,研究了玻璃组成对玻璃的分相和析晶的影响.结果表明:当组成中MgO/Al2O3越大且同时SiO2含量越高,越利于该系统产生分相.当MgO/Al2O3大于3且SiO2含量大于68mol％时,水淬试样产生分相.SiO2含量较高时,分相液滴很容易聚集在一起,形成连通的蠕虫状分相粒子.随着SiO2含量的降低,玻璃的析晶放热峰温度逐渐降低,而且析晶放热峰变得尖锐,玻璃析晶趋势增强.当SiO2含量越低且MgO/Al2O3越大时,越利于该系统析晶.

Effect of Composition on Phase-Separation and Crystallization of MgO-Al2O3-SiO2 System Glass

The influences of compositions on phase-separation and crystallization of MgO-Al2O3-SiO2 system were discussed.Samples of different component points in every stage of thermal treatment were analysed by XRD、TEM and DTA.The results show that the higher MgO/Al2O3 and the higher SiO2 content in the composition,the more beneficial to produce phase-separation of MgO-Al2O3-SiO2 system.When MgO/Al2O3 is greater than 3 and SiO2 contentis more than 68mol％,the phase-separation can be observed in the quenching sample.When SiO2 content is high,it is easy to gather the liquid droplets together to form a interconnected worm-like second phase.With the decreasing of SiO2 content,the crystallization peaktemperature(Tp) of the glass gradually decreases,and the crystallization exothermic peak becomes sharp,the glass crystallization improves.The lower the SiO2 content and the higher MgO/Al2O3,the glass crystallization becomes easier.