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就菱方晶体建立了简单菱方晶格气体模型,用密度波理论研究了菱方固溶体的有序结构.根据无序态固溶体系统的能量在Brillouin区高对称点取极值的特点,确定驱动有序结构的波矢量.由此推导出7种有序结构类型,包括4种完全有序结构和相应的A基元浓度.根据这些理论结果预报了A1/4B3/4,A1/2B1/2,A3/4B1/4型有序固溶体的存在.根据刚玉型二元金属氧化物的特点,用二次有序化理论对其中阳离子的有序结构进行研究,预报了(A1/4B3/4)2O3,(A1/2B1/2)2O3和(A3/4B1/4)2O3型有序固溶体的存在.根据理论结果对文献报道的典型实验结果进行了解释,包括刚玉结构的过渡金属掺杂α-Al2-xTxO3(T=Sc,Y,La,Ac,x=0.5)晶体,刚玉型α-FeAlO3晶体,α-Fe2-xCrxO3固溶体,以α-Al2O3,α-Cr2O3和α-Y2O3为主要成分的抗高温氧化的多元膜和复合膜等.这些有序结构的确定为材料结构和性能的第一性原理研究等奠定了基础.
A simple rhombic lattice gas model was established for rhombic crystals, and the ordered structure of rhombic solid solution was studied by using the density wave theory.According to the characteristics of the high symmetry point in the Brillouin region, Order structure of the wave vector. From this, we deduce seven kinds of ordered structure types, including four kinds of fully ordered structure and the corresponding concentration of A element.According to the results of these theories, A1 / 4B3 / 4, A1 / 2B1 / 2 , A3 / 4B1 / 4 type ordered solid solution.According to the characteristics of corundum-type binary metal oxide, the ordered structure of the cation was studied by the theory of quadratic ordering, and the (A1 / 4B3 / 4) 2O3, (A1 / 2B1 / 2) 2O3 and (A3 / 4B1 / 4) 2O3 ordered solid solution.According to the theoretical results, the typical experimental results reported in the literature are explained, including the transition metal doped α- Al 2-xTxO3 (T = Sc, Y, La, Ac, x = 0.5) crystals, corundum-type α-FeAlO3 crystals and α-Fe2-xCrxO3 solid solutions containing α-Al2O3, α-Cr2O3 and α-Y2O3 as main components High temperature oxidation of multi-membered and composite films, etc. The determination of these ordered structures laid the foundation for first-principles study on the structure and properties of materials.