Microstructure evolution and electrochemical properties of carburized CSS-42L steel by high dose carbon ion implantation

The precipitation of Cr-rich carbides creates significant chromium depletion zones against the steel matrix, which are more sensitive to pitting corrosion. In this work, high dose carbon ion implantation was introduced to eliminate the negative effect of Cr-rich carbides precipitated in carburized CSS-42L steel. X-ray photoelectron spectroscopy (XPS) analysis reveals the co-existence of graphite bonds and carbide bonds for the carbon implanted samples. Amorphization transformation for Cr-rich carbides and precipitation of nanocrystalline Fe2C carbides in the implanted layer are confirmed by transmission electron microscopy (TEM) and glancing incidence x-ray diffraction (GIXRD) investigations. The electrochemical results indicated that the microstructure evolution induced by carbon ion implantation was beneficial in improving the corrosion property of carburized CSS-42L steel, in which the intergranular corrosion was suppressed and the corrosion degree was also modified.