Mechanical properties of multilayer Ti/N/ZrN coatings

초록

Process parameter dependence of hardness and adhesion properties of TiN/ZrN multilayer coatings deposited onto a high speed tool steel substrate by using a reactive sputtering technique was investigated. The hardness and the adhesion strength of the formation of microcracks causing a deterioration of the mechanical properties. The optimum gas flow ratio, N2/Ar, for the highest hardness and adhesion was found to be 0.2. The optimum annealing temperature in view of the hardness and the adhesion of the coatings is 400℃. Annealing at temperatures higher than 400℃ would be detrimental for the mechanical properties due to oxidation. The effect of the compositional wavelength of TiN/ZrN on the hardness of the costimg confirms the result of previous works, in that the coherency strains are relaxed as the wavelength increases through the insertion of misfit dislocations, resulting in a decrease of both the hardness and the adhesion strength of the coatings.