Structure and Properties of Multicomponent Arc-PVD Ti–Cr–Mo–Ni–N Coatings Deposited on HG20, HS123 and HV420 Carbide Alloys and C80W1 Tool Steel

Although the arc-PVD Ti–Cr–Mo–Ni–N coatings deposited on HG20, HS123 and HV420 carbide alloys and C80W1 tool steel have approximately similar elemental and phase compositions, they differ in morphology, macrostructure, and macrostress level. The coating deposited on steel exhibits macrolayering, a wider coating–substrate transition zone and tensile structural macrostresses. In contrast, coatings deposited on carbide alloys develop compressive structural macrostresses. This behavior can be explained by the overheating during deposition caused by ion bombardment. Overheating is more pronounced for a coating on steel because the thermal diffusivity of steel is lower than that of hard alloys. The Ti–Cr–Mo–Ni–N coating on C80W1 steel exhibited a lower hardness (approximately 20.3 GPa) than the coatings on the carbide alloys (21.7–25.1 GPa). It also showed lower resistance to cohesive failure, with Lc3 ≈ 30 N, compared with ≈94 N for the coatings on the carbide alloys. Here, Lc3 denotes the critical load for cohesive cracking of the coating induced by plastic extrusion of the substrate material. The coating on steel also exhibited a higher specific wear rate at 20 °C and 500 °C. Its K20 and K500 values were 49.80 and 74.20, respectively. The corresponding values were 4.19 and 11.99 for HG20, 2.91 and 12.35 for HS123, and 6.33 and 14.71 for HV420, respectively, expressed in units of 10−6 mm3·N−1·m−1.