Defect structure of alumina-rich nonstoichiometric magnesium aluminate spinel
Defect structure of alumina-rich nonstoichiometric magnesium aluminate spinel
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DOI：
10.1016/j.ssi.2005.09.013
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发表时间：
2006-01-16
影响因子：
3.2
通讯作者：
Fukatsu, N
中科院分区：
文献类型：
--
作者：
Okuyama, Y;Kurita, N;Fukatsu, N
为了明确富铝非化学计量铝酸镁尖晶石中氢的溶解机理与缺陷结构之间的关系，采用火焰熔合法生长了几种单晶组成，并分别采用红外吸收和阿基米德方法研究了氢溶解度和质量密度对其组成的依赖关系。氢的溶解度与水分压的平方根成正比，并随氧化铝过量量的增加而增加。单晶密度略小于基于缺陷结构的计算值。氢的溶解度和密度的组成依赖性可以用模型来解释，其中氧化离子空位的浓度随着氧化铝含量的增加而增加，这是由于Mg位点接受过量Al离子的能力下降。(c) 2005 Elsevier B.V.版权所有
In order to clarify the relation between the dissolution mechanism of hydrogen and the defect structure in alumina-rich nonstoichiomettic magnesium aluminate spinels, several compositions of single crystals were grown by the flame fusion method and their compositional dependence of the solubility of hydrogen and that of the mass density were studied by the IR absorption and Archimedes methods, respectively. The solubility of hydrogen increased in proportion to the square root of the water partial pressure and with the increase in the excess amount of alumina. The densities of the single crystals were slightly less than the value calculated based on the reported defect structure. The compositional dependence of the solubility of hydrogen and that of the density can be explained by the model in which the concentration of the oxide ion vacancy increases with the alumina content due to the decrease in the capability of the Mg site to accept the excess Al ion. (c) 2005 Elsevier B.V. All rights reserved.