Effect of deposition time ratio on substrate bonding and the friction and wear properties of Ti/TiN–Cu multilayer thin films on Si 3 N 4 substrates

To improve film–substrate adhesion and the tribological performance of hard coatings on Si 3 N 4 ceramics, Ti/TiN–Cu multilayer films were deposited on Si 3 N 4 substrates by magnetron sputtering. Multilayers were produced with a fixed number of deposition cycles while varying the ratio of Ti to TiN–Cu deposition times. The multilayer architecture substantially enhanced film–substrate bonding. Among the tested time ratios, Among the tested time ratios, sample F2 (Ti:TiN-Cu deposition-time ratio = 1:2) exhibited the highest second critical load (Lc2) of 27.8 N, representing a 58% increase over TiN.This sample also displayed the lowest coefficient of friction (COF) = 0.12, the narrowest wear scar width, 307.4 μm, and a reduced wear rate of 2.64 × 10 −6 mm 3 /(N·m). These results indicate that strengthening film adhesion concurrently lowers both friction and wear.