Ar-implantation on AISI 304 stainless steel against pit initiation processes

Ion implantation has been widely used as a surface modification technique to improve surface properties. However, a few works have been performed using argon as implanted element in order to modify the corrosion behaviour of stainless steels (SS). In the present study, the implanted ion was Ar+ at an energy of 80 keV and the implanted dose was in the range of 1 × 1015 to 1 × 1017 Ar+/cm2 in an AISI 304 stainless steel. The surface bombardment with inert gases mainly produces structural changes, modifying topography and morphology. Nevertheless, the surface analysis carried out by X-ray Photoelectron Spectroscopy (XPS) shows that Ar-implantation modifies the surface composition of the passive layer and, therefore, the protective properties of the SS. In order to measure these modifications on the corrosion behaviour, electrochemical noise tests at open circuit potential were performed. The results obtained show that Ar-implantation decrease the corrosion resistance of AISI 304 SS and this effect is more important with the increasing implantation dose.