The chromization on hot-rolled Fe40Mn20Cr20Ni20 high-entropy alloys by pack cementation

As a surface modification technique, chromization is often used in steels to improve their wear, corrosion, and oxidation resistances. High-entropy alloys (HEAs) with excellent properties can be applied in extreme environments, perhaps to further improve their resistance to external environments by chromization. In this work, the chromization of hot-rolled Fe40Mn20Cr20Ni20 HEA was carried out by pack cementation. A chromized coating of 120 µm with the body-centered cubic (BCC) structure and a diffusion layer of 30 µm were obtained by chromizing at 1473 K for 12 h. Based on the growth kinetics of the coating, the relationship between the thickness of the chromized coating and chromized temperature as well as the time was modeled to visualize. After chromization, due to the higher chromium content of the coating, the Vickers hardness of was increased from 150 HV0.1 of hot-rolled HEA to more than 500 HV0.1, the wear rate was significantly reduced, and the dominant wear mechanisms for both hot-rolled and chromized HEAs under three test environments involved abrasion and adhesive wears. Besides, the corrosion resistance was promoted in NaCl solution (3.5 wt%). Thereby, the present work provides guidances for chromization on HEAs.