Investigation of the passivation process of plastically deformed 316L stainless steel using the high frequency capacitance obtained by EIS

Abstract

This paper was devoted to the study of changes of electrochemical processes (dissolution, passivation) induced by the plastic strain of a 316L austenitic stainless steel in a chloride acid solution (H2SO4 2 M + NaCl 0.5 M). For this purpose, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods have been used for various plastic strain values. In order to only assess the effect of internal stresses created by various dislocation configurations on the dissolution and passivation processes without considering the surface roughness impact, electrochemical experiments have been carried out after polishing the specimen surface. The obtained results show that the electrochemical parameters (corrosion current, activation current peak, high frequency capacitance) change with the increase of plastic strain with the same behavior as the work hardening phases of the material in relation to dislocation pattern.