PbF_2·SiO_2基玻璃陶瓷的溶胶-凝胶法制备及结构转变研究

采用溶胶-凝胶法制备了 PbF2?SiO2纳米晶玻璃陶瓷块体;利用 TG-DSC 和 IR 技术分析了干凝胶在热处理过程中有机基团的分解及内部原子键合方式的演变;结合 XRD 和 TEM 研究了凝胶玻璃中 PbF2纳米晶粒的长大过程,并分析了 Er3+掺杂的影响。结果表明,采用此方法制备的 PbF2?SiO2纳米晶玻璃陶瓷具有较好的成形性,晶化温度在 320℃左右;经 480℃热处理,镶嵌在玻璃基体中的 PbF2晶粒尺度约为 10～25nm,材料透明性良好。在 PbF2?SiO2系统中掺入少量的 Er3+,将提高 PbF2的晶化温度,降低玻璃陶瓷的显微硬度;掺杂可能对 PbF2晶粒表面原子的活性起抑制作用,阻碍晶粒的表面迁移,使晶粒的生长速度明显降低。

Preparation and Structural Transformation of PbF_2·SiO_2 Based Glass Ceramics Prepared by Sol-gel Method

Bulk PbF2?SiO2 based glass ceramics was prepared by sol-gel method. The decomposition of organic radicals and the evolution of chemical bonds in the xerogel were studied by TG-DSC and IR. The growth of PbF2 nanocrystals and the effect of Er3+ doping were investigated by XRD and TEM. The results confirm that sol-gel method could prepare PbF2?SiO2 glass ceramics with good formability. The crystallization temperature of the xerogel is about 320 ℃. After being heat-treated at 480 ℃, the size of PbF2 crystals is in the range of 10～25 nm, and the glass ceramics exhibits good transparency. Doping with small amount of Er3+ can increase the crystallization temperature. It seems that Er3+doping has the effect of restraining the activity of atoms on the crystal surface, hindering the crystal surface mobility and thus decreasing obviously the growth rate of grains.