ELECTROCHEMICAL METHODS APPLIED TO THE STUDY OF TRIBO-CORROSION PHENOMENA

摘要

A self designed equipment was used to perform tribo-corrosion test on hard steel and on C40 steel coated by cermet coatings obtained by high velocity oxygen fuel powder spray process (HVOF). Corrosion kinetics as well as corrosion mechanism are very well followed and controlled by means of a dedicated Potentiostat/Galvanostat. The user-friendly interface permits to easy set-up different types of experiment, including load/speed/duration program and various electrochemical techniques. The equipment permits to carefully follow the mechanical and electrochemical aspects of tribocorrosion phenomena. Therefore, it is suitable for detailed study of passivation mechanism and passive film removal of sliding systems under several working load. Lubricated wear conditions can be simulated as well and anodic polarizations can be imposed, to analyze coating characteristics while controlling or stimulating the corrosion phenomena. The effects of rotation speed and applied load on electrochemical parameters were analysed. It was shown that Ecorr values are noticeably affected by variations of testing conditions because of both fluidodynamic changes and abrasion mechanisms.