Effects of the target-to-substrate distance on the microstructure and properties of TiN coatings fabricated by pulse-enhanced vacuum arc evaporation

摘要

Pulse-enhanced vacuum arc evaporation (PEVAE) is promising in surface engineering and produces coatings with better structure and properties. In PEVAE, the target-to-substrate distance (D (t-s)) affects the substrate ion current and ion bombardment energy which is closely related to the structure and properties of the coatings. In this work, TiN coatings are deposited on high-speed steel (HSS) and silicon plates by the traditional DC mode and PEVAE mode at various D (t-s) and the substrate current, microstructure, morphology, mechanical properties, and corrosion resistance are evaluated. The results show significant improvements of 42.8%, 33%, and 51.6% for the average substrate current (I (Ave.)), ion bombardment energy (E (bi)), and deposition rate (a (d)) in the PEVAE mode and as D (t-s) is increased, I (Ave.), a (d) and E (bi) decrease less substantially compared to the DC mode indicating that TiN coatings are still bombarded by more ions despite a larger D (t-s). The hardness and wear rate (W (R)) in the PEVAE mode increase by 41.4 and 56.1%, respectively, and the corrosion resistance and adhesion strength are improved as well. When D (t-s) is increased, the hardness and corrosion resistance decrease and W (R) increases in both modes but the effects are less significant in the PEVAE mode.