Wear–corrosion mechanism of hard chromium coatings

Hard chromium coatings are frequently used for application where corrosion and wear degradation are combined, as an example in earthmovers, in mining transport systems or in moulds for plastics. The aim of this work is to study the mechanisms of tribocorrosion of hard chromium coated steel bars in a sodium chlorides solution under sliding wear. Using a self-made wear–corrosion apparatus, many parameters were monitored to analyse both kinds of damage: the mechanical and the electrochemical one. Different test conditions were considered by changing imposed load on the counterface and rotation speed. It was observed that the change of testing parameters was insignificant on the degradation mechanism: mainly adhesive wear was observed and secondary abrasive wear (at test beginning) and localised corrosion were present. Degradation synergy was also observed both by electrochemical tests and weight loss measurements.