XPS and AES surface analysis of WC‐Co‐(Cr) cemented carbide after immersion in neutral solution

The binder phase Co in WC‐Co cemented carbide is dissolved easily in corrosive media (even in neutral solution), which has limited its application in a wider range. In this paper, the influence of Cr on corrosion resistance of WC‐Co immersed in neutral solution was studied, with a focus on the surface chemistry of the corrosion product. The results show that in neutral solution, the corrosion is mainly caused by the selective dissolution of Co and the dominant surface corrosion product after immersion is Co (OH) 2 . The corrosion resistance of WC‐Co cemented carbide can be improved by the addition of Cr. This can be explained by the formation of more protective chromium containing oxide on the binder phase of WC‐Co‐Cr alloy, leading to reduced corrosion rate.