(Ti,Al)N–Ni nanostructured coatings: Thermal stability, heat resistance, electrochemical behavior, and adhesive strength with a substrate

Abstract

In this work, thermal stability and oxidation resistance at temperatures up to 800°C are studied for (Ti,Al)N–(8–10 at %)Ni coatings with a thickness on the order of 4 µm and a crystallite size below 20 nm, which have been prepared via ion–plasma vacuum arc deposition. The composition and structural characteristics of coatings remain stable during 1-h heating in vacuum of 10_–4 Pa at temperatures of 600 and 700°C. Heating at a temperature of 800°C leads to an increase in the crystallite size and a decrease in microstrains of a ceramic phase, which is accompanied by a reduction in the hardness of the coating from 51–53 to 31–33 GPa. The coatings are heat resistant up to 800°C and characterized by cohesive failure in scribing. The adhesive strength of coatings with a substrate exceeds 85 N. Studying electrochemical behavior reveals the high efficiency of (Ti,Al)N_0.87–Ni coatings in corrosion protection of cutting tools in acid and alkaline environments.