过渡金属元素 X（X ＝W，Mo，Cr）对 RuAl合金抗氧化性影响的机理

基于密度泛函理论的第一性原理，通过计算 RuAl 合金氧化物 Al2 O3和 RuO2的氧化能，考察过渡金属元素 X （X ＝W，Mo，、Cr）加入到 RuAl 合金后的占位及对氧化物 Al2 O3和 RuO2的结构稳定性影响。研究表明：经过渡金属元素 X 合金化后，Al2 O3和 RuO2的氧化能均有所增大，增大 Al2 O3氧化能的顺序为：W ＞Mo ＞Cr；增大 RuO2氧化能的顺序为：Mo ＞Cr ＞W，且 RuO2氧化能增大幅度大于 Al2 O3。通过态密度、电荷密度等因素的分析，阐明了 W 对提高 RuAl 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 RuAl 金属化合物发生内氧化过程，有利于在 RuAl 表面层的横向方向上形成连续性致密的 Al2 O3氧化层。

Transition Metal Elements X(X =W,Mo,Cr)Performance Impact Mechanism RuAl Antioxidant Study

Based on the first-principles density functional theory,the placing in the RuAl alloy and the stability effect of the transition metal elements X(X =W,Mo,Cr)on the structure of the oxides Al2 O3 and RuO2 were investigated through the calculation of the oxi-dation energy of the oxides Al2 O3 and RuO2 of RuAl alloy.It is found that the oxidation energy of Al2 O3 and RuO2 is all increased after the alloying of the transition metal X.The sequence of the size increasing for the Al2 O3 oxidation energy is W >Mo >Cr.The sequence of the size increasing for the Al2 O3 oxidation energy is Mo >Cr >W.Among them,the best effect for increasing the anti-oxidation capa-bility to the RuAl alloy is W alloying.Simulfaneously,the analysis of statu’s density and chargy density indicates that the basic reason for W alloying to increase the RuAl anti-oxidation performance is that the co-valent characteristics between the bonds Al-O /Ru-O are reduced,and the ionic band characteristics between the bonds Al-O /Ru-O are increased.Therefore,the alloying of the metal element X can promote the generation of the existing condition for the inner-oxidation process of RuAl metal oxidation,the continuous and dense Al2 O3 oxidation layer is formed on the transverse direction of RuAl surface.