ABSTRACT

Ion implantation is a surface modification technique able to modify the surface properties while leaving the bulk untouched. It is especially interesting when the dimensions of the pieces must not be modified.

Nitrogen implantation has been widely used for increasing the hardness and wear resistance of stainless steels (SS). However, the protective properties against corrosion of this modification are still not clear and, depending on the parameters employed during the treatment, different results were obtained. In this work, the corrosion resistance of N-implanted stainless steels were studied by means of Electrochemical Impedance Spectroscopy (EIS), which allows the study of modifications on the corrosion mechanism. Doses ranging from 1 x 10¹⁴ up to 1 x 10¹⁷ ions/cm² were tested at an energy of  80keV. In order to study whether the modifications found are due to the chemical effect of the N implanted or due to the physical modifications introduced during the implantation process, the same study was carried out with Ar-implanted samples in the same conditions.

Atomic Force Microscopy (AFM) images of the samples were taken to observe modifications on the surface roughness with ion implantation. Changes in surfaces morphology can generate modifications on the electrochemical response.