Effect of cermet substrate characteristics on the microstructure and properties of TiAlN coatings.

The composition and structure of substrate materials have important influences on coating performance, especially in terms of bonding strength and coating hardness, which determine whether the coating can be used for a given application. In this study, a TiAlN coating is deposited on Ti(C,N)-based cermet (TC) substrates with 0wt%–20wt% WC by arc ion plating. The influence of cermet substrate characteristics on the structure and properties of the TiAlN coating is then researched. Results show that the TiAlN coating deposited on the TC substrate has a columnar grain structure. As WC increases, the strength ratio of I₍₁₁₁₎/I₍₂₀₀₎ and adhesive strength of TiAlN gradually increases. In the absence of WC in the substrate, the preferred orientation of the TiAlN coating is (200). As WC increases, the preferred orientation of the TiAlN coating becomes (111) and (200). Notable differences in adhesive strength between the coating and substrate could be attributed to the micro-structure and composition of the latter. Scratching results show that the adhesive strengths of the TiAlN coating on the 0wt%–20wt% WC cermet substrate are 52–65 N. Among the coatings obtained that on the TC substrate with 15wt% WC presents the highest H/E and H³/E², which indicates that this coating also features the best wear resistance. The failure mechanisms of the coated tools include coating peeling, adhesive wear, and abrasive wear. As the cutting speed increases, the degree of flank wear increases and the durability of the coating decreases accordingly. Increases in WC result in an initial decrease followed by a gradual increase in the flank wear of the coated cermet inserts. [ABSTRACT FROM AUTHOR]