Ropo Matti, Punkkinen Marko, Kuopanportti Pekko, Yasir Muhammad, Granroth Sari, Kuronen Antti, Kokko Kalevi
Department of Physics and Astronomy, University of Turku, 20014, Turku, Finland.
Faculty of Engineering and Natural Sciences, Tampere University, 33014, Tampere, Finland.
Sci Rep. 2021 Mar 15;11(1):6046. doi: 10.1038/s41598-021-85243-0.
The adsorption of oxygen on bcc Fe-Cr(100) surfaces with two different alloy concentrations is studied using ab initio density functional calculations. Atomic-scale analysis of oxygen-surface interactions is indispensable for obtaining a comprehensive understanding of macroscopic surface oxidation processes. Up to two chromium atoms are inserted into the first two surface layers. Atomic geometries, energies and electronic properties are investigated. A hollow site is found to be the preferred adsorption site over bridge and on-top sites. Chromium atoms in the surface and subsurface layers are found to significantly affect the adsorption properties of neighbouring iron atoms. Seventy-one different adsorption geometries are studied, and the corresponding adsorption energies are calculated. Estimates for the main diffusion barriers from the hollow adsorption site are given. Whether the change in the oxygen affinity of iron atoms can be related to the chromium-induced charge transfer between the surface atoms is discussed. The possibility to utilize the presented theoretical results in related experimental research and in developing semiclassical potentials for simulating the oxidation of Fe-Cr alloys is addressed.
利用从头算密度泛函计算方法研究了两种不同合金浓度的体心立方Fe-Cr(100)表面上氧的吸附情况。对氧-表面相互作用进行原子尺度分析对于全面理解宏观表面氧化过程必不可少。在前两层表面层中插入了多达两个铬原子。研究了原子几何结构、能量和电子性质。发现一个中空位置是比桥位和顶位更优的吸附位置。发现表面层和次表面层中的铬原子会显著影响相邻铁原子的吸附性质。研究了71种不同的吸附几何结构，并计算了相应的吸附能。给出了从中空吸附位置出发的主要扩散势垒的估计值。讨论了铁原子氧亲和力的变化是否与铬诱导的表面原子间电荷转移有关。探讨了在相关实验研究以及开发用于模拟Fe-Cr合金氧化的半经典势中利用所呈现理论结果的可能性。
