热液循环
结晶
溶解
哈夫尼亚
四方晶系
降水
水热合成
相(物质)
亚稳态
化学工程
材料科学
结晶学
矿物学
化学
晶体结构
冶金
立方氧化锆
物理
陶瓷
气象学
工程类
有机化学
作者
Goran Štefanić,Svetozar Musić,Krešimir Molčanov
标识
DOI:10.1016/j.jallcom.2004.06.064
摘要
Hydrothermal crystallization of hydrous hafnia at 90 and 120 °C, was monitored at pH 3, 7, 9.5 and 13, using X-ray powder diffraction analyses. The obtained results showed that hydrothermal crystallization proceeded much more slowly in a neutral pH medium than in an acidic or alkaline medium. Phase analysis of the products of hydrothermal treatment showed that, regardless of pH, hydrous hafnia crystallized into m-HfO2. Stabilization of a metastable cubic or tetragonal HfO2 occurred upon adding a sufficient amount of stabilizing Na+ ions. Similarities and differences between the hydrothermal crystallization of HfO2 and the hydrothermal crystallization reported for ZrO2 were discussed. It was concluded that in both cases hydrothermal crystallization proceeds via a dissolution/precipitation mechanism in the whole pH range.
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