Theoretical predictions of composition-dependent structure and properties of alumina-rich spinel

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• 作者：Bingtian Tu ; Hao Wang ; ^{shswangh@whut.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Xin Liu ; Weimin Wang ; Zhengyi Fu
• 关键词：Alumina-rich spinel ; First-principles calculation ; Composition-dependence ; Optical properties ; Mechanical properties
• 刊名：Journal of the European Ceramic Society
• 出版年：2016
• 出版时间：March 2016
• 年：2016
• 卷：36
• 期：4
• 页码：1073-1079
• 全文大小：2110 K

文摘

Alumina-rich spinel (MgO·nAl₂O₃, n ≥ 1) was described as a solid solution of MgAl₂O₄ and Al_8/3O₄ (γ-Al₂O₃) with formula of Mg_1–xAl_2(1+x/3)O₄ (0 ≤ x ≤ 1). Five redefined supercell models of MgO·nAl₂O₃ were constructed to investigate the composition-dependence of structural, electronic, optical and mechanical properties. The first-principles calculations were developed with high accuracy to evaluate the lattice constant, electronic structure, dielectric function and elastic constants. The detailed structural information was presented by analyzing the variations in lattice constant, interstitial volume and anion parameter with the content of γ-Al₂O₃. The composition-dependent bulk modulus, shear modulus and electronic structure of alumina-rich spinel were well discussed. As increased the content of Al, the mechanical properties showed an increasing trend, while the optical absorption in the UV region presented a blue-shift of ∼1.2 eV. These theoretical results provided a basis for understanding the crystal structure and intrinsic properties of alumina-rich spinel.