Drying Effect on Thermal Behavior and Structural Modifications of Hydrous Zirconia Gel
Drying Effect on Thermal Behavior and Structural Modifications of Hydrous Zirconia Gel
复制标题
干燥对水合氧化锆凝胶热行为和结构改性的影响
DOI：
10.1111/j.1551-2916.2008.02635.x
复制
发表时间：
2008
影响因子：
3.9
通讯作者：
C. Pagliuca
中科院分区：
文献类型：
--
作者：
G. Dell’Agli;G. Mascolo;M. C. Mascolo;C. Pagliuca
采用四种不同的干燥方式对三种单一水合氧化锆凝胶原料进行干燥，得到了12种纯氧化锆干凝胶样品。特别是，采用以下干燥方式：在室温下在空气中干燥，在60° C或110°C的空气烘箱中干燥，最后通过冷冻干燥进行干燥。由此产生的干凝胶显示，在加热时，非常不同的反应性，影响纯氧化锆的结构相变。该动力学特征是解释室温下氧化锆亚稳相形成机理的关键。实验结果表明，事实上，亚稳相是有利的快速结晶速率，而稳定的，由一个缓慢的结晶速率。这些发现可以解决文献中报道的氧化锆亚稳性的相互矛盾的结果。
Adopting four different drying modalities on three single stocks of hydrous zirconia gel, 12 samples of pure zirconia xerogels were obtained. In particular, the following drying modalities were adopted: drying in air at room temperature, drying in air oven at 60° or 110°C, and, finally, drying by freeze-drying. The resulting xerogels showed, on heating, very different reactivity, affecting the structural phase transformations of pure zirconia. The kinetics feature could be the key to explain the formation mechanism of the metastable phases of zirconia at room temperature. The experimental results show, in fact, that the metastable phase is favored by a fast crystallization rate, whereas the stable one, by a slow crystallization rate. These findings could resolve the conflicting results on the metastability of zirconia reported in the literature.