Li2O-ZnO-SiO2系微晶玻璃的结晶及其封接特性

CRYSTALLIZATION AND SEAL CHARACTERISTIC OF Li_2O-ZnO-SiO_2 GLASS-CERAMICS

采用X射线衍射定性分析、差热分析、扫描电镜等手段研究了Li_2O-ZnO-SiO_2(组成为9.0%Li_2O,27.1%ZnO,55.6%SiO_2,2%K_2O,3.2%P_2O_5,3.1%CaO,质量分数)玻璃粉末处理后的微晶玻璃的的结晶特性。结果表明:当热处理温度低于800℃时,主晶相为半蜷曲状二硅酸锂和硅酸锌,次晶相为圆柱状α-方石英;当热处理温度超过800℃后,α-方石英逐步转变成β-方石英并成为主晶相,次晶相为二硅酸锂和硅酸锌且部分晶体重熔转变成玻璃。重熔过程有利于与金属材料封接。当热处理温度为950℃,封接后的封接件(不锈钢壳体,铜针引线)中微晶玻璃的外观良好,呈乳白色。密封气密性良好。500℃热冲击实验[(-55±2)～(500±5)℃]后,微晶玻璃无损伤。微晶玻璃在500℃时绝缘强度为3.3×10^(12)Ω·cm,膨胀系数为129×10^(-7)/℃。

The microstructure and crystallization of Li2O-ZnO-SiO2 glass-ceramics with a composition of 9.0%（mass fraction,the same below）Li2O,27.1%ZNO,55.6%SiO2,2%K2O,3.2%P2O5,3.1%CaO was investigated after heat treatment at different temperatures by X-ray diffraction and differential thermal analysis and scanning electron microscopy.The results show that when the heat treatment temperature is lower than 800℃,the main crystal phases in the glass-ceramics are Li2Si2O3 and ZnSiO3 with half curling type structure,the secondary crystal phase is a-quartz with circular column form;when the heat treatment temperature is over 800℃,α-cristobalite gradually transforms intoβ-cristobalite that is the main crystal phase in the glass-ceramics,the secondary crystal phase are Li2Si2O3 and ZnSiO3 and parts of them will remelt to transform into glass phase.The remelting is in favor of sealing with metal.A seal piece with stainless steel shell and cupper needle core and using Li2O-ZnO-SiO2 glass as seal material was heat treated at 950℃for 20 min,the appearance of milk white glass-ceramic in the seal piece with good leak tightness is best.The seal piece after thermal shock test for（-55±2）℃-（500±5）℃is complete and the glass-ceramic no damage.The glass-ceramic has a insulating strength of 3.3×10^12Ω·cm at 500℃,a coefficient of expansion of 129×10^-7/℃.