FeCrxMnAlCu高熵合金在3.5wt% NaCl溶液中的耐腐蚀性能

Corrosion Behavior of FeCrxMnAlCu High-Entropy Alloys in 3.5wt% NaCl Solution

摘要:

采用真空电弧熔炼制备FeCr?MnAlCu （x=0，0.5，1.0，1.5，2.0） 高熵合金，通过电化学动电位极化曲线和浸泡实验的方法研究了该高熵合金在室温下3.5wt% NaCl溶液中的腐蚀行为。微观组织结果表明，x=0的高熵合金具有体心立方相结构，而x=0.5~2.0时该高熵合金具有面心立方+体心立方双相混合结构。腐蚀结果表明，随着Cr含量的增加，高熵合金的耐腐蚀性能增加。其中，x=2.0时的高熵合金表现出最佳的耐腐蚀性能，具有最高的自腐蚀电位（E_corr=-0.354 V vs. Ag/AgCl）、最小的自腐蚀电流密度（I_corr=1.991×10^-6 A·cm^-2）和最小的腐蚀速率（0.0292 mm/a）。在腐蚀后的高熵合金表面形成了氧化物和氢氧化物的复合钝化膜，且Cr₂O₃含量随着Cr含量的增加而增加，从而有效地提高了钝化膜的稳定性和保护性能。

Abstract:

In this study, FeCr?MnAlCu (x=0, 0.5, 1.0, 1.5, 2.0) high-entropy alloys were fabricated using vacuum arc melting, and the corrosion behavior of these alloys in 3.5wt% NaCl solution at room temperature was investigated by electrochemical dynamic potential polarization curves and immersion experiments. The microstructure results show that the high-entropy alloy with x=0 has a body-centered cubic phase structure, whereas the high-entropy alloys with x=0.5–2.0 have a mixed face-centered cubic+body-centered cubic dual-phase structure. The corrosion results show that the corrosion resistance of the high-entropy alloy is increased with the increase in Cr content. Among them, the high-entropy alloy with x=2.0 exhibits the optimal corrosion resistance: the highest self-corrosion potential (E_corr=-0.354 V vs. Ag/AgCl), the smallest self-corrosion current density (I_corr=1.991×10^-6 A·cm^-2), and the smallest corrosion rate (0.0292 mm/a). The composite passivation film of oxides and hydroxides is formed on the surface of the corroded high-entropy alloys, and the Cr₂O₃ content is increased with the increase in Cr content, which effectively improves the stability and protective properties of the passivation film.