Study of Corrosion Resistance of AISI 420 Stainless Steel after High Temperature N and Si Ion Implantation

The effects of high temperature nitrogen and silicon ion implantation on the corrosion resistance of martensitic stainless steel 420 are investigated. Silicon implantation is used to achieve a Si-rich region near the stainless steel surface to improve the localized corrosion resistance, and plasma nitriding and high-temperature ion implantation are used to further improve the surface micro-hardness and corrosion resistance. The effects of different substrate temperature, implantation dose and implantation energy on the surface properties are assessed. The corrosion measurements are carried out in a NaCl solution using electrochemical impedance spectroscopy. The surface microhardness, crystal structure and microstructure are measured by microhardness measurement, XRD, SEM and AES. The process is applied to industrial injection molds in the production line, and the results are reported in this paper.