Wear Behaviour of Coloured Stainless Steel

Abstract

Interference film deposition is an attractive alternative for the formation of coloured protective layers on the surface of stainless steel for various applications. The process involves the growth of an oxide film (chromium and iron oxide), by chemical or electrochemical methods, on the surface of the stainless steel imparting a colour, which changes from blue to green depending on the thickness of the film. The aim of the present investigation was to assess the wear sliding behaviour of coloured stainless steel, produced by a pulsed electrochemical process. The specimens were obtained by using anodic colouring coupled with cathodic hardening, and some specimens were post-heat treated at 250°C for 200 h. Sliding wear tests were conducted in air, without lubrication, using a pin on disc tribometer for 100 m. AISI 1086 pins were used as the counterpart. It was determined that the heat treated specimens have a better sliding resistance compared with both untreated specimens and the substrate. Wear scar morphologies and wear mechanisms were determined using SEM. There was clear evidence of material transfer from the pin to the coloured steel specimen in every test. The pins presented a mixed abrasion–adhesion mechanism, where the adhesive wear was predominant.