Study of wear-corrosion synergy with a new microelectrochemical technique

A new method for the investigation of tribocorrosion properties has been de veloped. The current density of a metal probe in an electrolyte under rubbi ng condition can be measured. The electrochemical microcell consists of a m icrocapillary (inner diameter 0.84 mm). The rubbing partner is an Al2O3 tub e, which rotates inside the microcapillary. Rotational speed, load and appl ied electrochemical potential can be varied so that it is possible to analy se the corrosion rate during rubbing at various controlled conditions. With the present method, activation and repassivation of the analysed area (are a under rubbing condition) can be studied separately. In order to quantify wear-corrosion, profilometer measurements of the treated zone have been con ducted. In many tribocorrosion systems, the surface passivation and degrada tion introduced by corrosion processes have critical influence on the perfo rmance and lifetime of the metal. The susceptibility of a passive metal to tribocorrosion degradation may be related to the removal rate of the protec tive oxide film and the repassivation rate of the bare metal exposed to an aggressive environment. The object of this work is to understand the intera ction between passive and attacked surface areas as well as the interaction of the electrochemical and mechanical wear on tribocorrosion systems. Abra sion of different stainless steels in aqueous environment was studied with the new tribometer during polarisation and potentiostatic measurements. (C) 1999 Elsevier Science S.A. All rights reserved.