Structure and mechanical behavior evaluation of CVD multilayer coatings deposited on Ti(C,N)-based cermets

Abstract

Evaluating the static and dynamic properties of different multilayer coatings on cermet is helpful to guide the coating design of cermet tools. The radar chart method is used to systematically evaluate the static and dynamic performance of the three multilayer coatings. The results show that the presence or absence of the Al2O3 coating in the coating system will affect the friction and cutting properties of the coating-substrate system. In addition, the growth texture of each layer of coating will also affect the performance of the coating-substrate system. The static properties of TiN/TiCN/α-Al2O3/TiN (A1) coating are better than TiN/TiCN/TiC/TiN (A0) and TiN/TiCN/κ-Al2O3/TiN (A2). Compared with A0 and A2, the morphology of the A1 coating has larger undulations and the largest roughness. However, the average friction coefficient of A1 is the smallest at 25 °C. Especially at 750 °C, the particle size of the coating surface will affect the friction performance. The order of the friction coefficient of three multilayer coatings at 25 °C is A1<A2<A0, while the friction coefficient of the composite coatings at 750 °C is A0<A1<A2. The flank morphologies show that TiN (220) growth texture is more wear-resistant than (111) growth texture, α-Al2O3 (104) growth texture is more wear-resistant than κ-Al2O3 (013) growth texture. Surface energy spectrum shows that the Al2O3 coating has a strong ability to hinder element diffusion. Based on the radar chart, whether it is dynamic performance or static performance, the overall properties of A1 is the best. Compared with A0, the static performance of A2 is better than that of A0, but the dynamic performance is not as good as A0.