Structure, morphology and mechanical properties of AlCrN coatings obtained by the method of cathodic arc evaporation

Abstract

CrAlN coatings have been formed on steel substrates (HS6-5-2) using cathodic arc evaporation. The influence of nitrogen pres-sure and substrate bias voltage on the properties of CrAlN coatings formed from Al80Cr20 cathode, such as: chemical and phase composition of the coatings, their surface morphology, deposition rate, hardness and adhesion to the substrate have been investigated. It has been determined that the rate of the deposition of coatings in the nitrogen atmosphere with the pressure of 3 Pa is the highest and that with the increase of the negative bias voltage of the substrate the deposition rate decreases. The roughness parameter Ra of the coating surface decreases as the nitrogen pressure increases during their formation. Presumably, this is related to the reduction of the amount of macroparticles on the surface of the coating. The hardness of the coatings (taking into account the measurement uncertainty) is independent of the nitrogen pressure, but it increases with the increase of the negative bias voltage of the substrate. The adhesion of the coating increases with the increase of the nitrogen pressure to 3–4 Pa, and then it decreases. The increase in the negative bias voltage of the substrate during the formation of the coating deteriorates its adhesion to the substrate.