Ab initio atomistic thermodynamics study on the oxidation mechanism of binary and ternary alloy surfaces
Ab initio atomistic thermodynamics study on the oxidation mechanism of binary and ternary alloy surfaces
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二元和三元合金表面氧化机理的从头原子热力学研究
DOI：
10.1063/1.4907718
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发表时间：
2015-02-14
影响因子：
4.4
通讯作者：
Shen, Yaogen
中科院分区：
文献类型：
--
作者：
Liu, Shi-Yu;Liu, Shiyang;Shen, Yaogen
利用从头算密度泛函理论和热力学形式理论相结合的方法，建立了二元和三元合金表面氧化的微观机理，并对氧化的实验结果提供了明确的解释。我们构建了三种不同的Nb-X(110) （X = Ti， Al或Si）二元合金表面氧吸附的三维表面相图（SPDs）。根据得到的SPD，我们得出了热力学氧化的一般微观机理，即在富o条件下，均匀单相SPD （I型）和不均匀双相SPD （II型）分别对应于添加X元素后的持续完全选择性氧化和非持续部分选择性氧化。此外，通过对两种分离二元合金表面能的比较，揭示了三元合金氧化机理的热力学框架，为Nb三元合金表面的选择性氧化行为提供了认识。利用这些一般的微观机制，人们可以基于热力学的考虑来预测任何二元和多组分合金表面的氧化行为。(C) 2015 AIP出版有限责任公司
Utilizing a combination of ab initio density-functional theory and thermodynamics formalism, we have established the microscopic mechanisms for oxidation of the binary and ternary alloy surfaces and provided a clear explanation for the experimental results of the oxidation. We construct three-dimensional surface phase diagrams (SPDs) for oxygen adsorption on three different Nb-X(110) (X = Ti, Al or Si) binary alloy surfaces. On the basis of the obtained SPDs, we conclude a general microscopic mechanism for the thermodynamic oxidation, that is, under O-rich conditions, a uniform single-phase SPD (type I) and a nonuniform double-phase SPD (type II) correspond to the sustained complete selective oxidation and the non-sustained partial selective oxidation by adding the X element, respectively. Furthermore, by revealing the framework of thermodynamics for the oxidation mechanism of ternary alloys through the comparison of the surface energies of two separated binary alloys, we provide an understanding for the selective oxidation behavior of the Nb ternary alloy surfaces. Using these general microscopic mechanisms, one could predict the oxidation behavior of any binary and multi-component alloy surfaces based on thermodynamics considerations. (C) 2015 AIP Publishing LLC.