Improved corrosion resistance of Ni-22Cr-13Mo-4W Alloy by surface nanocrystallization

Surface modification treatments were carried out on Alloy 22, a nickel base Ni-22Cr-13Mo-4W alloy, using shot peening process followed by low-temperature annealing. Electrochemical corrosion experiments were carried out on the surface modified specimens in hot acid chloride solution. Passivation and Mott-Schottky (M-S) analysis were carried out in sulfuric acid solution at room temperature. Improved passivity and better electronic properties of passive film were observed on the surface modified specimens that could be attributed to the surface nanocrystallization.