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基于密度泛函理论的第一性原理,通过计算Ru Al合金氧化物Al2O3和Ru O2的氧化能,考察过渡金属元素X(X=W,Mo,、Cr)加入到Ru Al合金后的占位及对氧化物Al2O3和Ru O2的结构稳定性影响。研究表明:经过渡金属元素X合金化后,Al2O3和Ru O2的氧化能均有所增大,增大Al2O3氧化能的顺序为:W>Mo>Cr;增大Ru O2氧化能的顺序为:Mo>Cr>W,且Ru O2氧化能增大幅度大于Al2O3。通过态密度、电荷密度等因素的分析,阐明了W对提高Ru Al抗氧化性能的根本原因是降低了Al-O和Ru-O的共价键特性,增加了Al-O和Ru-O的离子键特性;金属元素X(X=W,Mo,Cr)可阻碍Ru Al金属化合物发生内氧化过程,有利于在Ru Al表面层的横向方向上形成连续性致密的Al2O3氧化层。
Based on the first principle of density functional theory (DFT), the calculation of the oxidation energies of RuAl alloy oxides Al 2 O 3 and Ru O 2 and the occupation of transition metal X (X = W, Mo ,, Cr) And on the structural stability of oxides Al2O3 and Ru O2. The results show that the oxidation energies of Al2O3 and Ru O2 increase with the alloying of transition metal X, and the order of increasing the oxidation energy of Al2O3 is: W> Mo> Cr. The order of increasing the oxidation energy of Ru O2 is: Mo> Cr> W, and the oxidation energy of Ru O2 increased more than that of Al2O3. Based on the analysis of the state density and charge density, it is clarified that the fundamental reason why W can improve the oxidation resistance of Ru Al is to reduce the covalent bonding properties of Al-O and Ru-O, increase the content of Al-O and Ru-O (X = W, Mo, Cr) can hinder the internal oxidation process of RuAl metal compounds, which is conducive to the formation of continuous dense Al2O3 oxide layer in the lateral direction of RuAl surface layer.