Tribocorrosion behaviors of CrN coating in 3.5 wt% NaCl solution

Chromium nitride coatings are synthesized on the stainless steels by plasma immersion ion implantation and deposition. The microstructure and tribocorrosion behaviors of the as-deposited coatings are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, reciprocating-sliding tribometer and electrochemical testing. The results show that the CrN coatings have a typical columnar growth structure consisting of face-centered cubic crystals. The CrN coatings greatly enhance the corrosion resistance and wear resistance of the stainless steel. However, frictional forces induce numerous micro-cracks which act as the diffusion channels for NaCl solution. Multi-scale Cl ion corrosion occurs simultaneously during the tribocorrosion and a force-corrosion synergy interaction induces the multi-degradation (e.g., intersecting cracks and layer delamination) of the CrN coating. The synergistic damage mechanisms of wear and corrosion are systematically discussed.