Electrochemical study of the influence of H2O2on 316L stainless steel implants in Hank’s solution at body temperatures

Abstract

The stability of the oxide layer at the surface of stainless steel is very important to protect medical implants, knowing that chemical product like hydrogen peroxide can change its behaviour. When used medical implants go through various steps in which hydrogen peroxide is involved. Corrosion of 316L stainless steel implant in Hank’s solution at body temperatures was evaluated for different concentrations of hydrogen peroxide. Open circuit potential (OCP) and potentiodynamic tests were carried out. According to the results, when the concentration of H2 O2 is increased, the potential becomes more positive but the passive layer formed at the surface of the implant remains unstable. Independently of hydrogen peroxide concentration, the corrosion potential shifts to more negative values proportionally to the increase of immersion times from 0 to 72 h. When immersions are superior to 72 h, in the presence of high hydrogen peroxide concentrations, the breakdown potential increase positively with the increase of the immersion time (ennoblement occurs). Rising Hank’s solution temperature containing H2 O2 from 37 °C to 42 °C increased pitting corrosion of 316L SS implant. Micrographs taken after polarization, showed a particular layout of pits which may explain the stainless steel implants rupture and lead to the improvement of their elaboration.