Comparison of the wear and corrosion behavior between CrN and AlCrN coatings deposited by Arc-PVD method

Abstract

In this investigation, we studied deposition of chromium nitride (CrN) and aluminum chromium nitride (AlCrN) coatings on the steel substrate by using cathodic arc evaporation technique (Arc-PVD). Therefore, the wear and corrosion behavior of the CrN and AlCrN coatings were compared. Applying cathodic arc evaporation at 200 °C for 90 min led to a coating with approximately 2 micrometers thickness. In order to compare the properties of CrN and AlCrN coatings, all of the Arc-PVD methods coating parameters were kept at a constant value within the deposition of coating having the duty cycle of 50 percent, bias voltage of −100 V, and the target current of 100 A. For characterizing the crystal structure and microstructure of the coatings, x-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) were utilized. In order to evaluate the coatings adhesion and the wear behavior, Rockwell-C indenter and the pin-on-disk test were used, respectively. Moreover, a potentiodynamic polarization device was used in 3.5% NaCl solution for studying the corrosion behavior of the coatings. The results revealed that CrN coating has the lower friction coefficient but AlCrN coating showed better wear resistance. Also, CrN coating had a better corrosion resistance than AlCrN on account of the uniform surface morphology and the absence of void which protects the substrate from the corrosive medium.