Study on the Corrosion Behavior of Additively Manufactured NiCoCrFeyMox High-Entropy Alloys in Chloride Environments

This study aims to determine the optimal Mo content for corrosion resistance in two alloys, FeCoCrNiMox and Fe0.5CoCrNiMox. The alloys were fabricated using laser powder bed fusion (LPBF) technology with varying Mo contents (x = 0, 0.05, 0.1, 0.15). The corrosion behavior of these alloys was investigated in 3.5 wt.% NaCl solution at room temperature and 60 °C using electrochemical testing and X-ray photoelectron spectroscopy (XPS). The results show that all alloys exhibit good corrosion resistance at room temperature. However, at 60 °C, both alloys without Mo addition exhibit severe corrosion, while the Fe0.5CoCrNiMo0.1 alloy demonstrates the best corrosion resistance while maintaining the highest strength. The enhanced corrosion resistance is attributed to the optimal molybdenum addition, which refines the passive film structure and promotes the formation of Cr2O3. Furthermore, molybdenum oxide exists as MoO42− ions on the surface of the passive film, significantly improving the alloy’s corrosion resistance in chloride-containing environments.