Effect of process parameters on mechanical and tribological performance of pulsed-DC sputtered TiC/a-C:H nanocomposite films

Abstract

Mechanical, structural, chemical bonding (sp 3 /sp 2), and tribological properties of films deposited by pulsed-DC sputtering of Ti targets in Ar/C 2 H 2 plasma were studied as a function of the substrate bias voltage, Ti-target current, C 2 H 2 flow rate and pulse frequency by nanoindentation, Raman spectroscopy and ball-on-disc tribometry. The new findings in this study comprise: dense, column-free, smooth, and ultra-low friction TiC/a-C:H films are obtained at a lower substrate bias voltage by pulsed-DC sputtering at 200 and 350 kHz frequency. The change in chemical and phase composition influences the tribological performance where the TiC/a-C:H films perform better than the pure a-C:H films. In the case of TiC/a-C:H nanocomposite films, a higher sp 2 content and the presence of TiC nanocrystallites at the sliding surface promote formation of a transfer layer and yield lower friction. In the case of a-C:H films, a higher sp 3 content and higher stress promote formation of hard wear debris during sliding, which cause abrasive wear of the ball counterpart and yield higher friction.

Effects of A-elements (A Si, Ge or Sn) on the structure and electrical contact properties of Ti–A–C–Ag nanocomposites

“…This in combination with high raw material prices motivates investigations for alternative solutions. While others have studied TiC-based nanocomposites as tribological coatings [2,3,4,5,6,7,8,9], we found that such nanocomposites can function as an electrical contact material [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. In our previous works, coatings consisting of nanocrystalline (nc) TiC embedded in an amorphous (a) C or SiC matrix were deposited by dc magnetron sputtering.…”

Tribological Properties of Si-Doped Graphite-Like Amorphous Carbon Film of PEEK Rubbing with Different Counterparts in SBF Medium

“…Basically, elastic modulus also plays an important role in determining the wear behavior of material, attributed to that the elastic strain to failure is related to the ratio of hardness (H) and elastic modulus (E). Shaha et al [46] pointed out that the hardness ratio of the tribo-pair and the coating material makes markedly sense on the wear behavior of the coating. When the hardness ratio is above r c1 (0.5-0.8), the wear rate of the counterpart decreases; as the increased hardness ratio is close to r c2 (1-1.4), almost no wear is observed.…”

Structure, mechanical and tribological properties of HfCx films deposited by reactive magnetron sputtering

“…As protective coating, transitional metal carbides have lower coefficient of friction (COF) and better wear resistance in comparison with transitional metal nitrides, hence many carbides films with combination of excellent hardness and great tribological behaviors have been extensively investigated such as ZrC, TiC, NbC, WC, etc. [7][8][9][10][11][12]. For instance, the carbon (C) content of ZrC films deposited by Meng et al.…”