Corrosion would lead to the failure of materials during service, causing huge economic losses and catastrophic accidents, particularly in chemical industries. In this work, a series of novel high-entropy alloys (HEAs) (FeCoCrNiMo_xNb_x) with exceptional corrosion resistance were designed. The phase composition, corrosion resistance, and passive film properties were determined through micro-characterization and electrochemical tests. First-principles calculations were further performed to unveil the corrosion resistance mechanism at the atomic level, especially the influence of elements on the corrosion resistance. It is found that the appropriate increase in the contents of Mo/Nb elements leads to the increased Laves phase in the HEAs and enhances the corrosion resistance of the HEAs. However, the excessive addition of Mo/Nb elements will cause more severe microgalvanic corrosion between FCC and Laves phases, resulting in a decrease in corrosion resistance. Theoretical calculations demonstrate that the Laves phase is more resistant to the attack of corrosive species. Additionally, the presences of Mo, Nb, and Cr elements in the HEAs facilitate the adsorption of H₂O/O on the HEAs surface, which promotes the formation of a protective passive film, and then provides better protection for the HEAs.

中文翻译：

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新设计的 FeCoCrNiMoxNbx 高熵合金优异耐腐蚀性的机理探索


腐蚀会导致材料在使用过程中失效，造成巨大的经济损失和灾难性事故，尤其是在化学工业中。在这项工作中，设计了一系列具有优异耐腐蚀性的新型高熵合金 （HEA） （FeCoCrNiMo_xNb_x）。通过微观表征和电化学测试确定物相组成、耐腐蚀性和钝化膜性能。进一步进行第一性原理计算，揭示了原子水平的耐腐蚀机理，特别是元素对耐腐蚀的影响。研究发现，Mo/Nb元素含量的适当增加导致高熵合金中Laves相的增加，并增强了高熵合金的耐腐蚀性。然而，Mo/Nb 元素的过量添加会导致 FCC 和 Laves 相之间出现更严重的微电腐蚀，导致耐腐蚀性下降。理论计算表明，Laves 相对腐蚀性物质的攻击更强。此外，高熵树脂中 Mo、Nb 和 Cr 元素的存在促进了 H₂O/O 在高熵合金表面的吸附，从而促进了保护性钝化膜的形成，从而为高熵合金提供更好的保护。