核化温度对CaO-Al2O3-SiO2系微晶玻璃晶化行为的影响

EFFECT OF NUCLEATION TEMPERATURE ON CRYSTALLIZATION BEHAVIOR IN CaO-Al_2O_3-SiO_2 SYSTEM GLASS-CERAMIC

利用DTA技术测定了某一配方的CaO-Al2O3-SiO2系玻璃的玻璃转变温度(Tg)与玻璃晶化温度(Tp),在Tg温度稍上,进行了不同温度的预核化处理。经预核化处理后的试样的DTA和SEM分析结果表明,随预核化温度的增加,晶化峰向低温方向移动,表明析晶能力在增强。在晶化温度稍上热处理,玻璃表面析晶,玻璃从表面到内部长成粗大的柱状晶,并以树枝状方式生长。在玻璃内部,尺寸细小的等轴晶镶嵌在玻璃相中。

Glass transition temperature and glass crystallization temperature of CaO-Al2O3-SiO2 system glass were measured by means of differential thermal analysis （DTA） technique. Pre-nucleation treatment was carried out at different temperatures slightly above Tg. The pre-nucleated sample DTA and SEM results showed that the crystallization peak moved to the lower temperature with increasing pre-nucleation temperature. It is considered that the crystallization ability is improved. When heat treatment was performed slightly above the crystallization peak, it crystallized on the surface of the glass and coarse columnar crystals grew from surface to interior in the style of dendrite. In the glass interior, tiny spherical grains were distributed in glass.