【摘要】 以SiO2 、Al2 O3、MgO和AlF3 为主要原料 ,采用高温熔融法 ,在一定温度下将原料熔化 ,然后将熔体浇铸到预热的模具中 ,经不同退火工艺得到基础玻璃 .将此玻璃快速加热到析晶温度 ,进行相同的析晶处理 ,得到玻璃陶瓷样品 .应用TEM、SEM和XRD等技术 ,系统研究了退火工艺对SiO2 -Al2 O3-MgO -F系玻璃陶瓷分相和析晶的影响 .结果表明 :随着退火温度的提高 ,玻璃的结构逐渐得到松弛 ,促进了Mg2 + 和F-离子的扩散 ,玻璃内分相程度逐渐增大 ,其分相形貌由液滴状连通状团簇状过渡 ;玻璃的分相程度对高温析晶时晶体的析出形态也有一定影响 ,与低温退火的玻璃相比较 ,高温退火时析出的云母晶体更加均匀 ;随着退火时间的延长 ,析出的晶体变得越来越细小 ,晶体间的交错度和晶体的均匀程度逐渐增大更多还原

【Abstract】 The SiO 2-Al 2O 3-MgO-F glasses were prepared by melting chemical grade reagents SiO 2, Al 2O 3,MgO and AlF 3, at the temperature 1 550 ℃ for 3 h and cooled in the pre heated models. The glasses were annealed at different temperatures and times and then heated to 1 050 ℃ for 5 h. The influence of annealing processes on phase separation and crystallization in SiO 2-Al 2O 3-MgO-F glass ceramics system was investigated by using TEM, SEM and XRD. The results showed that the increase of annealing temperature was benefitial to the diffusion of Mg 2+ ion and F ion and thus contributed to phase separation. As the temperature increases, the morphology of phase separation transforms from isolated droplets to consistent droplets and then to clusters. Moreover, it was found that the degree of phase separation has an effect on the morphology of precipitated mica crystals when heated to crystallizing temperature. With the increase of annealing temperature, mica crystals with finer and more uniform grain sizes were precipitated in the glass, and with the prolonging of annealing time, the mica crystals in the glass ceramics became more interlocked and more uniform in grain size.更多还原