超低膨胀微晶玻璃热处理工艺优化研究

采用熔融法制备了Li₂O-Al₂O₃-SiO₂系透明玻璃,以TiO₂、ZrO₂和P₂O₅为复合晶核剂对该玻璃进行热处理,获得了超低膨胀微晶玻璃。采用正交试验研究了热处理工艺参数对微晶玻璃热膨胀系数的影响,并通过计算分析获得了最优的热处理工艺参数,即核化温度为600 ℃,核化时间为3 h,晶化温度为820 ℃,晶化时间为5 h。在此热处理工艺制度下获得的微晶玻璃主晶相为β-石英固溶体,热膨胀系数为1.6×10^-8 ℃^-1。采用差热分析、X射线衍射分析、扫描电子显微镜分析、透射电子显微镜分析等手段研究了微晶玻璃的析晶情况和微观结构,并进一步分析了热处理工艺与微晶玻璃热膨胀性能和微观结构之间的对应关系。结果表明,微晶玻璃的热膨胀系数由晶相种类和含量决定,微晶玻璃内部晶相的尺寸和含量与热处理工艺密切相关。

Heat Treatment Process Optimization of Ultra-Low Expansion Glass-Ceramics

Li₂O-Al₂O₃-SiO₂ system transparent glass was prepared by melting method, and ultra-low expansion glass-ceramics were obtained by heat treatment with TiO₂, ZrO₂ and P₂O₅ as composite nucleating agents. The effects of heat treatment parameters on thermal expansioncoefficient of glass-ceramics were studied by orthogonal experiments. The optimal heat treatment parameters were obtained through calculation and analysis, that is, the nucleation temperature is 600 ℃, the nucleation time is 3 h, the crystallization temperature is 820 ℃, and the crystallization time is 5 h. The main crystalline phase of glass-ceramics obtained under this heat treatment process is β-quartz solid solution, and the thermal expansioncoefficient is 1.6×10^-8 ℃^-1. The crystallization and microstructure of glass-ceramics were studied by means of differential thermal analysis, X-ray diffraction analysis, scanning electron microscopy analysis and transmission electron microscopy analysis. The relationship between heat treatment process, thermal expansion properties and microstructure of glass-ceramics was analyzed. The results show that the thermal expansion coefficient of glass-ceramics is determined by the type and content of crystalline phase, and the size and content of crystalline phase which formed inside glass-ceramics are closely related to heat treatment process.