The role of Si on microstructure and high-temperature oxidation of CoCr2FeNb0.5Ni high-entropy alloy coating

Abstract In this study, the CoCr2FeNb0.5Ni high-entropy alloys coatings with and without Si were prepared on Cr-Mo-V steel via laser cladding. The oxidation behaviors of the HEAs coatings in N2-44CO2-6H2O gas at 800°C were systematically studied. Both coatings with and without Si consisted of FCC and Laves phases. Si atoms can be doped into Laves phase and improve the phase stability by reducing the spacing of crystal plane. The addition of Si improves the high temperature oxidation resistance since the (Cr, Si)Ox amorphous oxide layer can prevent oxygen from diffusing inward.