钠镁铝硅系统微晶玻璃的分相成核行为

本文以20Na2O、4CaO、12MgO、22Al2O3、4TiO2、38SiO2(重量百分比)组成玻璃为基础,制备了具有快速微晶化特性的钠镁铝硅系统微晶玻璃。分别采用差热分析技术(DTA)、X射线衍射技术(XRD)研究了不同热处理条件下玻璃分相成核的动力学、热力学和它们之间的依存关系。玻璃分相成核最大速率时的温度接近于923K。在成核温度的热处理对分相的放热行为有影响,成核导致系统自由能的降低与分相峰面积和峰值温度变化有关。用差热分析仪测量的玻璃分相的放热效应,是快速微晶化玻璃的重要特征,用XRD证实分相放热过程中没有微晶相产生。玻璃的分相过程为成核生长机理,采用修正kissinger方程求得玻璃分相活化能为310.445KJ/mol。

Nucleation in Phase Separation of Sodium-magnesium-alumina-silicate System Glass Ceramics

A quick-crystallized glass-ceramic of sodium-magnesium-alumina-silicate system was prepared with 20Na2O、4CaO、12MgO、22Al2O3、4TiO2、38SiO2(wt%).The kinetics,thermodynamics and relationship of nucleation in phase separation with different thermal treatments had been studied by differential thermal analysis(DTA) and X-ray diffractometry(XRD),respectively.The maximum temperature of nucleation in phase separation is about 923K.The thermal treatments at nucleation temperature have influence on the exothermic behavior of phase separation.The exothermic effect of glass phase separation by DTA was the important character of quick crystallization.With the result of XRD,we verified that there was no microcrystalline phase during the process of phase separation.It shows that phase separation mechanics of the glass is nucleation-and-growth mechanics.The activation energy of phase separation calculated by the modified Kissinger method is about 310.445KJ/mol.