溶胶-凝胶法合成钇铁石榴石(YIG)的凝胶化及热处理研究

GELATION AND ANNEALING PROCESS OF PREPARING NANOCRYSTALLINE Y_3Fe_5O_(12)(YIG) BY SOL-GEL METHOD

采用溶胶 -凝胶法制备了YIG纳米晶粉体材料 ,分析了合成条件 (pH值、浓度、反应温度和反应时间 )以及热处理等影响材料合成的主要参数 ,利用DTA ,TGA ,XRD ,TEM等手段对材料的制备过程和产物进行了分析 ,探讨材料制备最适宜的工艺条件 ,着重研究了热处理工艺对YIG的晶相和颗粒尺度等物理特性的影响 .实验结果表明 ,YIG相的形成是一个放热温度始于 5 0 0℃ ,峰位于 75 9℃的缓缓的放热过程 ,且样品平均晶粒尺寸随热处理呈规律性变化 ,因此可以通过采用溶胶

Yttrium iron garnet (YIG) nanocrystalline powders were prepared by sol-gel process. The influences of main parameters, including synthesize condition (pH values, molar ratio, reactive temperature and time) and annealing treatment, on YIG synthesized by the sol-gel method were taken into account. The transformations of precursor to gel and to crystalline phase were measured by DTA and TGA. Samples were characterized by XRD and TEM. The optimum processing conditions are discussed with a focus on the influence of annealing process on YIG phase and particle size. The results show that the growth of YIG is a slow process, characterized with a exothermic dome which begins at 500 ℃ and has a peak at 759 ℃. The changes of crystalline size with annealing temperature show some rules, and single phase nanometer powders of YIG are obtained through sol-gel process and proper annealing treatment.