A new electrochemical technique to study tribocorrosion at the micrometric scale

A new method to investigate the tribocorrosion properties of metals and alloys has been developed with which the current density of a metal probe in an electrolyte under rubbing conditions can be measured. The electrochemical microcell consists of a microcapillary (inner diameter 0.84 mm); the rubbing partner is an Al₂O₃ tube which rotates inside the microcapillary. Rotational speed, load and applied electrical potential can be varied, so that it is possible to analyse the corrosion rate during rubbing under various controlled conditions. With conventional tribocorrosion machines (e.g., pin-on-disc, ball-on-plate rig) and also with single-scratch test machines, the current measured also derives from surface areas which are not undergoing mechanical wear. In the present method, the activation of specific surface areas under rubbing conditions, and subsequent repassivation, can be studied separately.