Effect of nitrogen pressure and substrate bias voltage on the properties of Al–Cr–B–N coatings deposited using cathodic arc evaporation

Abstract

Cathodic arc evaporation deposition method was applied to forming Al–Cr–B–N coatings. The effect of nitrogen pressure (pN2) and substrate bias voltage (UB) on the properties of the coatings synthesized using Al50Cr30Br20 cathode was investigated. The chemical and phase composition of the coatings, their surface morphology together with the mechanical, tribological and anti-corrosion properties were investigated.

X-ray diffraction investigations have revealed the coatings phase composition. It is the mixture of h-AlN and c-CrN phases with crystallite size of about 4 nm. X-ray photoelectron spectroscopy has revealed amorphous BN phase in the investigated coatings. The majority of the coatings exhibit good adhesion, with the critical load above 75 N, except from the coating synthesized at the nitrogen pressure of 2 Pa. Coatings synthesized under various nitrogen pressure have a similar coefficient of friction of about 0.67. The wear resistance for these coatings increases with the nitrogen pressure during their synthesis. Friction coefficient of the coatings increases with substrate bias voltage, while the wear rate decreases.

Wear and corrosion tests show that the coating deposited under pN2 = 4 Pa and UB = −100 V is the most resistant to wear and corrosion from the sets of coatings tested.