High temperature tribological behavior of W containing diamond-like carbon (DLC) coating against titanium alloys

Influence of wetting and thermophysical properties of diamond-like carbon coatings on the frictional behavior in automobile gearboxes under elasto-hydrodynamic lubrication

“…The application of diamondlike carbon (DLC) coatings on machine elements deposited by means of physical vapor deposition (PVD) and plasma enhanced chemical vapor deposition (PECVD) is a common approach to meet the challenges of friction reduction, efficiency improvement and wear protection in various tribological systems [4][5][6][7][8][9][10][11]. This particularly includes piston rings, tappets, camshafts and plungers of injection systems and gearboxes [2,[9][10][11][12][13][14][15]. With regard to highly loaded rolling-sliding contacts as gears and rolling bearings, DLC coatings contribute to wear reduction due to their favorable effect on the load capacity in terms of pitting, scuffing and micro-pitting [4][5][6][7].…”

The high temperature tribological behavior of Si, O containing hydrogenated diamond-like carbon (a-C:H/a-Si:O) coating against an aluminum alloy

“…Cross-sections obtained using focused ion beam (FIB) milling (Carl Zeiss NVision 40 CrossBeam) process were examined by SEM. The details of FIB technique can be found in [25]. The cross-sectional samples were ion-milled from both sides to a thickness of less than 100 nm for transmission electron microscopy (TEM) observations made using a FEI Titan 80-300 LB-TEM operated at 80 kV to obtain high-resolution (HR-TEM) images and diffraction patterns of the coating and the transfer layers.…”

“…The hardness of the coatings was measured using a Hysitron TI 900 TriboIndenter equipped with a Berkovich nanoindenter tip with an indenter contact depth of 150 nm. Accordingly, the a-C:H/a-Si:O had a hardness of 13.5170.10 GPa (harder than H-DLC at 11.40 GPa [25]). …”

“…For tests in which no steady state COF occurred, the mean value of the entire curve (typically with high fluctuations) was reported. The fluctuations of an individual COF curve was calculated by determining the deviations from the average COF value as described in [25]. a-C:H/a-Si:O coatings were subjected to high temperature tests at 100, 200, 300, 400 and 500 1C.…”

Further improving the mechanical and tribological properties of low content Ti-doped DLC film by W incorporating

“…W. Yue and co-workers [20] investigated the W-doped DLC film, and found that the W content A c c e p t e d M a n u s c r i p t increased to 10.73 at.%, the hardness is increased to ~20 GPa, they all suggested that the enhancement of the hardness is probably due to the formation of hard phase WC disperses in the carbon matrix. Besides, many other researches also indicated that W is considered an effective doping element especially in improving the high temperature tribological properties of film [21][22].…”