Preparation and Thermal Expansion Behavior of Pollucite Powders by Sol-Gel Processing
Preparation and Thermal Expansion Behavior of Pollucite Powders by Sol-Gel Processing
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溶胶-凝胶法制备铯榴石粉体及其热膨胀行为
DOI：
10.2109/jcersj.99.686
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发表时间：
1991
影响因子：
1.1
通讯作者：
T. Mitamura
中科院分区：
文献类型：
--
作者：
Hidehiko Kobayashi;T. Terasaki;T. Mori;C. Ishihara;Sho Saito;H. Yamamura;T. Mitamura
以Al_2O_3溶胶、SiO_2溶胶和CsNO_3为原料，采用Sol-Gel法制备了偏辉石(Cs2O-⋅-Al_2O_3-⋅_4SiO_2)微粉，并对其单相稳定区域进行了研究。以SiO_2摩尔比为标准，当Cs2O：SiO_2摩尔比为0.91~1.02：4，Al_2O_3：SiO_2摩尔比为0.96~2.38：4时，合成了单相的闪锌矿粉末。室温下的晶格参数主要受Cs2O/SiO_2比的影响。高温X-射线衍射仪证实，组成的变化对滑石粉的热膨胀有很大的影响：从室温到200℃，随着CS2O/SiO_2比的降低，热膨胀系数减小，而在600℃以上，随着Al_2O_3/SiO_2比的增加，热膨胀系数增大，后者的增大趋势是由于焙烧过程中生成了少量的α-Al_2O_3。然而，当Cs2O/Al_2O_3比小于1时，没有观察到这种行为。
Pollucite (Cs2O⋅Al2O3⋅4SiO2) powders were prepared from a combination of Al2O3 sol, SiO2 sol and CsNO3 starting materials by sol-gel processing, and a stable region of single phase pollucite was investigated. The pollucite powders of single phase were synthesized when Cs2O:SiO2 and Al2O3:SiO2 molar ratios were 0.91-1.02:4 and 0.96-2.38:4, respectively, by standerdizing SiO2 molar ratio. The lattice parameters at room temperature were affected mainly by the Cs2O/SiO2 ratio. It was confirmed by a high temperature X-ray diffractometry that the thermal expansion for the pollucite powders is greatly affected by the change of compositions: The thermal expansion coefficient decreased with decreasing Cs2O/SiO2 ratio from room temperature to 200°C, and increased with increasing Al2O3/SiO2 ratio above 600°C. An increasing tendency of the latter has turned out to be caused by a slight amount of α-Al2O3 formed in the course of calcination. However, such behavior was not observed at the Cs2O/Al2O3 ratio of less than 1.