Corrosion behaviour of multilayer CrN coatings deposited by hybrid HIPIMS after oxidation treatment

Abstract

Chromium nitride coatings prepared by physical vapour deposition (PVD) show high hardness, high strength and good thermal conductivity, which makes them useful for cutting and forming tools. In this article, the microstructure and corrosion resistance of multilayer Cr/CrN coatings deposited by arc evaporation and hybrid high power impulse magnetron sputtering (hybrid HIPIMS) after oxidation between 500 and 800°C were examined. The average thickness of the coatings was about 3.5 µm. By means of the surface morphology analysis, elemental energy spectrometry and potentiodynamic polarization tests, the performances of the two groups of coatings have been compared. The results revealed that the coating deposited by the hybrid HIPIMS has stronger binding force with substrate, fewer surface defects and a denser structure. Also, the hybrid HIPIMS coatings have a better oxidation resistance and a better corrosion resistance compared to the arc evaporated coatings.

Keywords

• arc evaporation
• hybrid hipims
• cr/crn coating
• oxidation
• corrosion resistance
• potentiodynamic polarization test