Corrosion Resistance Properties of a Nickel–Chromium Steel Bar in Marine Atmosphere

Abstract

The corrosion behaviors of Ni–Cr and 20MnSi steel bars in a simulated marine atmosphere are compared using alternate immersion corrosion tests and electrochemical techniques. The microstructure features are characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrochemical measurements and alternate immersion corrosion tests demonstrate that the Ni–Cr steel bar has a more positive potential (– 0.397 V), lower corrosion current density (28.19 μA/cm2), and better corrosion resistance at a corrosion rate of 3.81 g/(m2· h) and corrosion depth of 4.27 mm/g. There are inner and outer rust layers on the Ni–Cr steel bar, the inner layer being dense and bonded to the steel substrate. The α -FeO(OH)/γ -FeO(OH) ratio of the rust layer on the Ni–Cr steel bar is greater, which contributes to a more denser rust layer enhancing corrosion resistance.