Effect of carbon addition on the microstructure and corrosion resistance of the CoCrFeNi high-entropy alloy

Interstitial atom doping can enhance mechanical properties and phase structure, but its impact on corrosion resistance is not well-researched. This study investigated the influence of carbon-doping on the microstructure and corrosion resistance of CoCrFeNi high-entropy alloys. The results show that alloy doped with a moderate carbon content (C0.3 alloy) have the best corrosion resistance in 3.5 wt% NaCl solution, while alloys with carbides (M7C3) show poor corrosion resistance. The stability, semiconductive property, and composition of the passivation films were characterized to reveal the corrosion mechanisms. These findings provide a theoretical basis for the development and application of carbon-doped high-entropy alloys.