Investigation of corrosion and tribological characteristics of annealed CrN/CrAlN coatings deposited by CAE-PVD

In this work, the variation of tribological and corrosion performances of as-deposited and annealed CrN/CrAlN multilayer coatings on 304 stainless steel substrates deposited by the cathodic arc evaporation process was investigated. It was found that annealing resulted in the decomposition of CrN to Cr 2 N. Also, the surface roughness increased as the annealing temperature increased due to the coalescence of macroparticles. Thus, the wettability of annealed samples decreased as the annealing temperature increased. The hardness decreased as the annealing temperature increased due to the increase in the crystallite size. The sample annealed at 400 °C had the lowest wear rate of 3.04 × 10 −5 mm 3 /Nm and 6.4 × 10 −5 mm 3 /Nm in ambient air and Ringer's solution, respectively, due to the optimum ratio of CrN and Cr 2 N, minimum crystallite growth, and optimum adhesion strength. Based on the electrochemical impedance spectroscopy results, the highest corrosion resistance was observed in the specimen annealed at 700 °C, which can be attributed to the existence of Cr 2 N and larger crystallite size in this multilayer coating.