Acta Metallurgica Sinica (English Letters) ›› 2025, Vol. 38 ›› Issue (3): 407-418.DOI: 10.1007/s40195-024-01804-y

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Enhancing the Corrosion Resistance of FeNiCoCrW0.2Al0.1 High-Entropy Alloy in 3.5 wt% NaCl Solution by Bilayer Passivation

Jingxiang Xu1(), Yuyan Yang2, Ruiyang Huang1, Xinwei Yuan1(), Huakang Bian2,3(), Zhenhua Chu1, Yang Wang4, Yanhua Lei5   

  1. 1College of Engineering Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
    2Materials Genome Institute, Shanghai University, Shanghai, 200444, China
    3Shanghai Frontier Science Center of Mechanoinformatics, Shanghai University, Shanghai, 200444, China
    4Research Institute of Frontier Science, Southwest Jiaotong University, Chengdu, 610031, China
    5College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai, 201306, China

Abstract:

The strong corrosion resistance and corrosion behavior of the FeNiCoCrW0.2Al0.1 high-entropy alloy in 3.5 wt% NaCl solution was investigated. In order to explain the Cl induced degradation of different metal oxides on the surface of the passivate film, the energy required for the interaction of the corrosion oxidation products NiO, CoO, Fe2O3, and Cr2O3 surfaces with Cl is compared and calculated based on the assumptions of the point defect model and the density functional theory by using the electrochemical impedance spectroscopy and the X-ray photoelectron spectroscopy for the analysis of the mono-double-layer structure and elemental compositions of passivate film in the corrosion process. The combined experimental and simulation results showed that the alloy passivates naturally in air, forming a single passivation layer. The compositional layering of the passivation film in 3.5 wt% NaCl solution occurred with the increase of the contact time with NaCl. A double-layer passivation with a two-layered combinatorial structure was formed due to the imbalanced depletion of Co and Fe during corrosion, and that the dense outer structure of this high-entropy alloy, which was made up of NiO and Cr2O3, provided the predominantly high corrosion resistance. This paper provided a new perspective to study the strong corrosion resistance of FeNiCoCr-based high-entropy alloys.

Key words: High-entropy alloys, Passivation films, Corrosion, Density functional theory