形核条件对Li_2O-Al_2O_3-SiO_2玻璃晶化和性能的影响  

Effect of Nucleation Temperatures on Crystallization Behavior and Properties of Li_2O-Al_2O_3-SiO_2 Glass

作　　者：胡安民[1] 梁开明[1] 彭飞[1] 周锋[1] 王国梁[1] 邵华[1] 

机构地区：[1]清华大学材料科学与工程系,北京100084

出　　处：《材料热处理学报》2004年第4期19-22,共4页Transactions of Materials and Heat Treatment

摘　　要：通过差热分析 (DTA)、X射线衍射分析 (XRD)和扫描电镜 (SEM)等方法 ,研究了形核条件对Li2 O Al2 O3 SiO2 (LAS)玻璃晶化和性能的影响。研究发现 ,当玻璃在最佳形核温度 74 5℃形核 2h和 6h后 ,Avrami常数n为 3 6和 3 5 ,晶体生长激活能为 2 76kJ mol和 2 80kJ mol。这表明在此形核温度下 ,改变晶化时间对玻璃的晶化影响较小。当晶化温度发生变化 ,晶化条件为 76 0℃ 2h时 ,Avrami常数降低到 2 8,晶体生长激活能增加到 312kJ mol。在 85 0℃晶化后 ,均获得了h 石英固溶体为主晶相的微晶玻璃。SEM观察发现晶粒均为等轴晶粒 ,表明析晶方式均为体积析晶。但随形核温度偏离最佳形核温度 ,从 74 5℃增加到 76 0℃ ,晶化后样品的晶粒尺寸加大 。The crystallization behavior of Li2O-Al2O3-SiO2 (LAS) glass crystallized at 745°C for 2 h and 6 h and at 760°C for 2 h was investigated by differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). After heating at 745°C for 2 h and 6 h, the Avrami constants for the glass samples are 3.6 and 3.5, and activation energies of crystal growth are 276 kJ/mol and 280 kJ/mol. The Avrami constant is 2.8 and activation energy of crystal growth is 312 kJ/mol for samples crystallized at 760°C for 2 h. The crystallized phase is identified as h-quartz solid solution and SEM observations indicate that glass-ceramic samples have fine equiaxial grain microstructure which indicates the occurrence of bulk crystallization. With increasing crystallization temperature to 760°C, the grain size increases and the values of flexural strength, hardness and fracture toughness of the glass-ceramics decrease.

关 键 词：玻璃 微晶玻璃 形核 晶化 Li2O-Al2O3-SiO2(LAS) 

分 类 号：TQ171.1[化学工程—玻璃工业] TG113[化学工程—硅酸盐工业]