K2O对LZAS微晶玻璃微观结构及热膨胀性能的影响

Effect of K2O on Microstructure and Thermal Expansion Coefficient of LZAS System Glass-ceramics

采用DTA、XRD、SEM、TEC（热膨胀系数）等分析手段研究了加入K20前后LZAS系统微晶玻璃的微观结构和热膨胀性能。结果表明，650℃晶化时，试样析出γⅡ-LZS和方石英晶体；725℃时，γⅡ-LZS逐渐转变为To—LZS晶体，并且出现β-石英固溶体；800℃时，p石英固溶体转变为p一锂辉石固溶体，晶粒尺寸逐渐长大。制得微晶玻璃的热膨胀系数在（50-130）×10^-7℃^-1（20-500℃）之间，其大小取决于晶相的种类和含量。并且K2O的加入降低了玻璃的转变温度、粘度，抑制了玻璃的析晶倾向，增大了微晶玻璃的热膨胀系数。

The effects of before and after the accession K2O on the microstructure and thermal expansion coefficient （TEC） of LZAS system glass-ceramic are studied by DTA,XRD,SEM and TEC test. The results show that the crystallization of γⅡ-LZS and cristobalite occurs after the glass is treated at 650℃. The crystallization transformation from γⅡ -LZS to 70-LZS takes place at 725℃, and the crystallization of β-quartz solid solutions also occurs at this temperature. At 800℃, the crystallization of β-quartz solid solutions transforms into β-spodumene solid solutions,and the size of crystal particles increases gradually. The thermal expansion coefficient of the glass-ceramics varies from 50 × 10^-7 ℃^-1 to 130×10^-7℃^-1 in the temperature range of 20-500℃, which is dependent on the type and the proportion of the crystalline phases presented. And with the addition of KeO, the glass transition temperature and viscosity are lower, the trend of the glass crystallization is inhibited,and the TEC of the glass ceramics is increased.