Corrosion behavior of CoxCrCuFeMnNi high-entropy alloys prepared by hot pressing sintered in 3.5% NaCl solution

Abstract

CoxCrCuFeMnNi high-entropy alloys (HEAs) were prepared by vacuum hot pressing sintered. The corrosion behavior has been evaluated using potentiodynamic polarization measurements and electrochemical impedance spectra (EIS). The corrosion current density (icorr) and average corrosion rate (Vcorr) of the alloys decreased with the increase of Co content. When the Co content increased to 2.0 mol from 0.5 mol, the values of icorr and Vcorr decreased to 6.95 × 10−6 A cm−2 and 0.07 mm year−1 from 4.04 × 10−5 A cm−2 and 0.43 mm year−1, respectively. EIS results reveal that the thickness and resistance of the passive films of CoxCrCuFeMnNi HEAs increased with the increasing of Co content, indicating the alloy with high Co content had a good corrosion resistance. The reasons for the improvement of corrosion resistance are related to higher the content of passivation elements and FCC2 phase. Keywords: High-entropy alloy, Hot pressing sintered, Polarization, EIS, Corrosion behavior