Effect of cobalt content on wear behaviour of Al0.4FeCrNiCox (x = 0, 0.25, 0.5, 1.0 mol) high entropy alloys tested under demineralised water with and without 3.5% NaCl solution

In the present work, the effect of cobalt content on wear behaviour of Al0.4FeCrNiCox (x = 0, 0.25, 0.5, 1.0 mol) high entropy alloys is comparatively studied under demineralized water and demineralized water + 3.5% NaCl solution, conditions. With the addition of more amount of cobalt, the microhardness is observed to decrease from 377 HV to 199 HV and the coefficient of friction and the specific wear rate are observed to increases under both the solution conditions. The worn surface is studied using field emission scanning electron microscope, energy dispersive x-ray spectroscopy, and optical profilometer to predict the mode of wear. The wear is found to occur under the combined action of adhesion along with delamination, plastic flow, and oxidation. The x-ray photoelectron spectroscopy results indicate that compound like, Fe2O3, Cr2O3, Al2O3 and Al(OH)3 are formed under DM water condition, and Fe3O4, Cr2O3, Al2O3, Al(OH)3 and FeCl3 are formed under DM + 3.5% NaCl solution condition.