The effect of contact configuration on the tribocorrosion of stainless steel in reciprocating sliding under potentiostatic control

Abstract

The effect of electrode configuration on the tribocorrosion behavior of a ferritic stainless steel in sulfuric acid solution was investigated. A truncated cone was rubbed against a stationary plate using a reciprocating motion pin-on-plate tribometer under potentiostatic control. Three contact configurations were investigated consisting of a ceramic pin rubbing on a steel plate (I), a steel pin rubbing on a ceramic plate (II), and a steel pin rubbing on a steel plate (III). The instantaneous current during each stroke and the evolution of the average current during an experiment were monitored. The total metal removal rate was measured by laser profilometry, the wear scar morphology was investigated by scanning electron microscopy and the electrochemical contribution to total wear was calculated from the measured anodic current using Faraday’s law. The results show that the electrochemical technique yields useful results for all three contact configurations including the metal–metal contact. The total wear volumes for configurations (I) and (II) were found to be comparable. The current transients suggested that the rate of metal loss was governed by the rate of mechanical depassivation. The total wear volume for configuration (III) was highest because of the larger metallic surface area and because of severe adhesive wear.