The influence of surface Fe on the corrosion of Mg
The influence of surface Fe on the corrosion of Mg
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DOI：
10.1016/j.jpcs.2022.110936
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发表时间：
2022-08
影响因子：
4
通讯作者：
Mengxuan Li;C. Cucinotta;A. Horsfield
中科院分区：
文献类型：
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作者：
Mengxuan Li;C. Cucinotta;A. Horsfield
铁是镁合金中常见的杂质，被认为会加速镁的腐蚀，导致镁的耐腐蚀性差。然而，对这种加速效应的原子理解仍然不完整。在这里，我们使用 Quantum Espresso 软件包执行的密度泛函理论模拟来研究几种 Fe/Mg 模型，计算相关的功函数、原子电荷以及 H 和 Fe 吸收能。与纯镁板相比，我们发现Fe的存在增加了功函数并降低了H吸附能。此外，观察到的总体趋势是，随着 Mg 基底上 Fe 原子之间相互作用的增加，Fe 吸收能降低。基于这些结果，提出了一种基于电荷重新分布的机制来解释 Fe 如何加速 Mg 的腐蚀。我们的研究结果提供了在原子水平上对镁腐蚀过程的深入了解，这可能为未来的防腐蚀措施提供信息。
Iron is a common impurity in magnesium alloys, and is acknowledged to accelerate Mg corrosion, contributing to Mg’s poor corrosion resistance. However, an atomistic understanding of this acceleration effect is still incomplete. Here we use Density Functional Theory simulations performed with the Quantum Espresso package to investigate several Fe/Mg models, calculating the associated work functions, atomic charges, and H and Fe absorption energies. Compared with a pure Mg slab, we find that Fe’s existence increases the work function and decreases the H adsorption energy. Furthermore, a general trend is observed that the Fe absorption energy decreases with increasing interaction between Fe atoms on the Mg substrate. Based on these results, a mechanism based on charge redistribution is put forward to explain how Fe accelerates the corrosion of Mg. Our findings provide insight into Mg’s corrosion process at the atomic level that might inform future measures to prevent corrosion.