Defect formation in β-Al2TiO5 and its influence on structure stability
Defect formation in β-Al2TiO5 and its influence on structure stability
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β-Al2TiO5 缺陷的形成及其对结构稳定性的影响
DOI：
10.1007/bf01154705
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发表时间：
1994
影响因子：
4.5
通讯作者：
J. Pilling
中科院分区：
文献类型：
--
作者：
R. Grimes;J. Pilling
原子模拟计算被用来预测肖特基，弗伦克尔和反位缺陷的形成时间。后者是如此容易形成，β-Al_2TiO_5结构被预测为基本上是阳离子无序的，与实验结果一致。相反，传统的肖特基和弗伦克尔障碍是可以忽略不计的和集群的空位缺陷强烈约束。这导致了一个显着的障碍，为解离为Al 2 O3和TiO 2，尽管积极的计算和观察到的生成焓的Al 2 TiO 5。讨论了MgO和过量TiO_2在β-Al_2 TiO_5中的固溶机理。
Atomistic simulation calculations are used to predict the formation enthalpies of Schottky, Frenkel and anti-site defects. The latter are so easily formed that the β-Al2TiO5 structure is predicted to be essentially cation disordered, in agreement with experimental results. Conversely, conventional Schottky and Frenkel disorder is negligible and clusters of vacancy defects are strongly bound. This leads to a significant barrier for dissociation to Al2O3 and TiO2 despite the positive calculated and observed formation enthalpy of Al2TiO5. The solution mechanisms of MgO and excess TiO2 in β-Al2TiO5 are discussed.