Effects of bias on surface properties of TiN films fabricated by hollow cathode discharge

Abstract

Titanium nitride ͑TiN͒ films have been deposited on AISI 304 stainless steel substrates using hollow cathode reactive plasma vapor deposition. Titanium is introduced by sputtering the Ti cathode nozzle and TiN is formed in the presence of a nitrogen plasma excited by radio frequency. The substrate bias voltage is varied from 0 to − 300 V to investigate its effect on the mechanical and structural properties of the films. X-ray diffraction results show the formation of TiN ͑111͒ and Ti 2 N ͑220͒ phases in the films. The sample bias has a critical influence on the thickness of the deposited films. The bias of −200 V leads to the thickest films ͑about 1680 nm͒ and the deposition rate is 18.7 nm/ min. The microhardness, root-mean-square ͑rms͒ roughness values, and tribological properties also exhibit nonlinear relationship with increasing bias voltages. The highest hardness of about 1027 hardness vickers and best wear resistance are achieved at a bias voltage of −100 V. Atomic force microscopy results reveal the lowest rms surface roughness of 3.19 nm when the bias voltage is −200 V.

Improved adhesion of TiN coatings on Al2O3–carbide composites by DFT calculations and experimental arc‐PVD synthesis

“…Regarding orientation relationships at the interfaces of TiN/Al 2 O 3 and TiN/WC, TiN(001)/Al 2 O 3 (0001), TiN(001)/WC(0001), TiN(111)/Al 2 O 3 (0001), and TiN(111)/WC(0001) were selected (Table 1). This is because TiN coatings deposited on various substrate materials including WC were frequently observed to be oriented parallel to (001) and (111) planes of cubic B1 TiN with respect to substrates 13‐18 . Although it has not been reported that TiN coatings deposited on composites containing Al 2 O 3 and WC, the preferred orientations of (001) and (111) planes of TiN on the present Al 2 O 3 –WC composites were confirmed by XRD and EBSD analyses in this study (see Section 3.3).…”

“…This is because TiN coatings deposited on various substrate materials including WC were frequently observed to be oriented parallel to (001) and (111) planes of cubic B1 TiN with respect to substrates. [13][14][15][16][17][18] Although it has not been reported that TiN coatings deposited on composites containing Al 2 O 3 and WC, the preferred orientations of (001) and (111) planes of TiN on the present Al 2 O 3 -WC composites were confirmed by XRD and EBSD analyses in this study (see Section 3.3). Moreover, (0001) planes of corundum Al 2 O 3 and hexagonal WC crystals are thermodynamically most stable surfaces, 19,20 so that the above interface orientations are most likely involved even in the real Al 2 O 3 -WC composites with TiN coatings.…”