A new method to improve the tribological performance of metal nitride coating: A case study for CrN coating

Abstract

Taking CrN coating as an example, a new refinement method was performed to improve the tribological performance of metal nitride coatings in the low temperature thermal cycling in humidity condition. After the low temperature thermal cycling post-treatment of −20 to 60 °C in high humidity environment of 80%, the structural and performance changes of the monolayer CrN coating fabricated by the multi-arc ion plating deposition technique were evaluated by using high-resolution transmission electron microscopy, scanning electron microscope equipped with EDS analyzer, X-ray diffraction, X-ray photoelectron spectroscopy and ball-on-disk tribometer. TEM observations and inverse Fourier-filtered images revealed dislocation-mediated mechanism in the treated state CrN coating, which was a key mechanistic process to enhance mechanical properties and wear resistance of CrN coatings after low temperature thermal cycling treatment. Moreover, the more physisorption and chemisorption of oxygen in treated CrN coating can be released and then pass through the defects and the channels between columnar crystal structure, finally arriving at the surface of coating to continuously participate in the tribo-contact interface reaction and produce more oxides as lubricants to effectively reduce friction coefficient and wear rate during dry-sliding.