The effect of mechanical and electrochemical parameters on the tribocorrosion rate of stainless steel in sulphuric acid

The tribocorrosion behaviour of a passive AISI430 ferritic stainless steel sliding against alumina in 0.5 M sulphuric acid has been studied using a tribometer that allowed for electrochemical measurements. The effects of applied potential, normal load, sliding velocity, sliding distance and alumina roughness on the friction, wear volume and anodic current were determined. The obtained results are interpreted in terms of a previously proposed theoretical model describing the average current in terms of depassivation rate and repassivation charge, taking into account the role of non-electrochemical parameters such as applied normal force, sliding velocity, metal hardness and contact configuration. Under the experimental conditions of the present study, the depassivation rate was found to govern the measured anodic current. Consideration of how mechanical and operational parameters affect the depassivation rate led to a consistent description of their effect on the tribocorrosion rate in accordance with the proposed model.