【摘要】 基于密度泛函理论的第一性原理,建立Al₂O₃和RuO₂晶胞模型,计算了Ru Al合金氧化物Al₂O₃和RuO₂的氧化能,结果显示:Al₂O₃的氧化能为–11.43 e V,RuO₂的氧化能为–2.28 e V,Al₂O₃比RuO₂的结构稳定性更好。通过态密度、Bander电荷密度等分析,发现W合金化提高RuAl抗氧化性能的根本原因是:由于W对O的吸附作用,使W周围的Al-O和Ru-O成键强度降低,Al₂O₃和RuO₂的氧化能减少,从而降低其结构稳定性。其中,Al₂O₃结构稳定性降低更加明显。同时,W合金化可降低RuAl合金体系基体内部的Al₂O₃结构稳定性,阻碍生成内氧化过程的生成条件,减少了垂直于表层界面的Al₂O₃的形成,促使表层界面的横向方向上Al₂O₃氧化层的成长,形成连续性致密的Al₂O₃氧化层,提高Ru Al抗氧化性。更多还原

【Abstract】 Al₂O₃ and RuO₂ crystal cell models were established by the first principles based on density functional theory. The internal oxidation energy of oxides Al₂O₃ and RuO₂ of Ru Al alloy was calculated. Results show that the oxidation energy of Al₂O₃ and RuO₂ is –11.43 e V and –2.28 e V, respectively. The structural stability of Al₂O₃ is better than that of the RuO₂. Through the analyses of density of states and charge density of Bander, it is found that the fundamental reason of W alloying enhancing the oxidation resistance of Ru Al is that due to the adsorption effect of W to O, the W decreases the Al-O and Ru-O bond strength, and reduces the oxidation energy of Al₂O₃ and RuO₂; thus the structural stability is reduced. The Al₂O₃ structure stability is decreased more significantly. At the same time, the alloying of W can reduce the structure stability of Al₂O₃ within the Ru Al alloy matrix system, block the formation condition of oxidation process, reduce the Al₂O₃ formation perpendicular to the surface interface, and promote the Al₂O₃ oxide layer growth on the surface interface along transverse direction; therefore, the continuous dense Al₂O₃ oxide layer forms, improving the oxidation resistance of Ru Al.更多还原