Response of duplex Cr(N)/S and Cr(C)/S coatings on 316L stainless steel to tribocorrosion in 0.89% NaCl solution under plastic contact conditions

Abstract

Two duplex coatings, Cr(N)/S and Cr(C)/S, were deposited on 316L stainless steel by magnetron sputtering. The effectiveness of these duplex coatings in improving the tribocorrosion behaviour of medical alloys under elastic contact conditions has been demonstrated in a recent publication. The present work focused on the response of these duplex coatings to tribocorrosion under plastic contact conditions. Tribocorrosion tests were conducted in 0.89 % NaCl solution at 37 o C at an initial contact pressure of 740 MPa and under unidirectional sliding conditions for sliding duration up to 24 h. The results showed that during sliding in the corrosive solution, the duplex coatings were plastically deformed into the substrate to a depth about 1 m. The Cr(C)/S duplex coating had sufficient ductility to accommodate the deformation without cracking, such that it was worn through gradually, leading to the gradual increase in open circuit potential (OCP) and coefficient of friction (COF). On the other hand, the Cr(N)/S duplex coating suffered from cracking at all tested potentials, leading to coating blistering after prolonged sliding at OCP and stable pit formation in the substrate beneath the coating at applied anodic potentials.

Effect of sliding conditions on micropitting behaviour of AISI 304 stainless steel in chloride containing solution

“…Mechanical wear may also be accelerated due to increased metal dissolution. This is the phenomenon of tribocorrosion, which has been increasingly studied during the past two decades [8][9][10][11]. These studies have identified the complex phenomena involved and the effect of wear on the electrochemical response of materials.…”

Surface finish effect on dry sliding wear behavior of thermally oxidized commercially pure zirconium

“…Such a ball-cratering technique has been widely used for measuring the thickness of thin coatings. It has recently been employed to aid in the examination of coating deformation beneath a wear track [29].…”

Coatings and Surface Modification of Alloys for Tribo-Corrosion Applications

“…Caha's research determined that, although the TiN coating did not enhance the tribocorrosion resistance of Ti-12Nb alloy due to the coating delaminating, applying a ZnO layer on top of the TiN coatings significantly improved performance by increasing microhardness and providing a robust physical barrier [75]. CrN and CoCrMo carbon S-phase layers were systematically studied by Bertram Mallia's group [76][77][78]. Among these, CrN/S coatings on 316L demonstrated remarkable tribocorrosion resistance, attributed to their high hardness and substrate adhesion.…”