Electrochemically controlled wear transitions in the tribocorrosion of ruthenium

This work presents an investigation of the tribocorrosion of ruthenium in sulphuric acid solutions. The study was focused on the effect of the electrode potential on wear of ruthenium during sliding against an inert alumina ball in a reciprocating sliding tribometer fitted with an electrochemical cell. Surface chemical and electrochemical properties were characterized using AES, XPS, SEM and electrochemical corrosion techniques. Results show that wear of ruthenium is negligible at cathodic potentials, increases in the active domain, then decreases when ruthenium is passive and increases again in the transpassive potential region. No enhancement of corrosion rate due to rubbing was observed in the passive and transpassive region. The change in wear is attributed to the presence of thin surface oxide films forming on ruthenium that influence the mechanical response of the metal and consequently its wear behavior.