The chemical wear (corrosion-wear) of novel Cr based hard coated 316L austenitic stainless steels in aqueous saline solution

Austenitic stainless steels are prone to galling and seizure in sliding contacts and display poor resistance to corrosion-wear. The purpose of this paper was to discover if the surface engineering of austenitic stainless steel via the application of Cr based hard coatings can alleviate this problem. Corrosion-wear tests using an aluminium oxide ball (pin) to slide against coated and uncoated AISI 316L in 0.9% NaCl solution under a normal force ∼1 N revealed degradation, under open circuit potential conditions, to be dominated by mechanically antagonized corrosion (Type I corrosion-wear) for all the test materials. A minor contribution to degradation was caused through superficial plastic deformation (micro-asperity shearing) of the contact surfaces took place but this was due to running-in and would have ceased after a short time once the asperities were flattened. It was accidentally discovered that pre-oxidation of the coated 316L steels, via vacuum heat treatment, resulted in an important and major improvement in corrosion-wear resistance.

► The aqueous corrosion-wear resistance of Fe–Cr–Ni coatings was tested.
► Some coatings were in the form of supersaturated solid solutions.
► Other coatings contained partially and completely transformed sigma phase.
► Type I corrosion-wear was the predominant material loss mechanism.
► Pre-oxidation caused a MAJOR improvement in the corrosion-wear resistance.