Effect of Noble Element Alloying on Passivity and Passivity Breakdown of Ni

摘要

Welding of stainless steels usually generates welding fumes containing carcinogenic hexavalent chromium (Cr~(+6)). To mitigate this problem, a new Ni-Cu-Pd welding consumable alloy has been developed. The addition of small amount of Cu and Pd in Ni enhances the galvanic compatibility of Ni with stainless steels and improves its localized corrosion behavior. In this paper, the artificial pit electrode technique and x-ray photoelectron spectroscopy (XPS) were used to study the benefits of Cu and Pd alloying. Pd showed the catalyzed the reduction of Cu at the bottom of the artificial pit, which enhanced the cathodic reaction and thus ennobled the deactivation potential making stable pit growth more difficult.