Effects of stirring action during friction on electrode processes of AISI 304 stainless steel in sulphuric acid

Abstract

It is known that tribology contact can accelerate the anodic reaction in alloys with passive films. Less attention has been paid in the literature on the cathodic reaction in materials under tribology contact. An AISI 304 stainless steel surface was subjected to linear reciprocating sliding friction in a 0.5 mol/L sulphuric acid solution. An integrated corrosion test cell with a wear tester was used. When stirring action was applied, an anodic shift of the OCP was observed. Stirring action also resulted in a cathodic shift of the measured current and polarity reversal when the sample was potentiostatically polarised at anodic potentials in the active region. An increase in current density was achieved by stirring when low cathodic potential was applied. Stirring, however, did not cause any significant change in current densities when a higher cathodic overpotential was applied. This was due to the bubble evolution-induced convection of the rapid precipitation of hydrogen bubbles accelerating mass transfer on the electrode surface. It was found that external stirring action could accelerate the kinetics of hydrogen evolution on the electrode surface in a state of slow hydrogen evolution. In addition, increased friction frequency could result in an increase in the amplitude of current transients.