Plasma coatings CrAlN and a-C:H for high efficient power train in automobile

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

“…Case hardening of the steel samples to a surface hardness of 60 ± 2HRC with a case hardening depth CHD N 1 mm provided for sufficient strength at high stresses and ensured a sufficient carrying capacity for the deposition of DLC coatings as reported in [7,8,26]. The metal and hydrogen containing diamond-like carbon (DLC) coatings a-C:H/ZrC g (ZrC g ) and a-C:H/nc-ZrC (nc-ZrC) were deposited at IOT in an industrial scale coating unit CC800/9 Custom from CemeCon AG, Wuerselen, Germany.…”

“…Round blanks of case hardened steel AISI 5115 (diameter Ø = 25 mm, height h = 8 mm, Ra = 0.02) and steel pins (diameter Ø = 6 mm, Ra = 0.02) were used as counterpart. As reported in [7,8,26], surface hardness of the case hardened blanks and pins was set to 60 ± 2HRC ensuring sufficient load carrying capacity for tribological tests. The DLC coated and uncoated steel samples were clamped into a rotation holding device and were heated up to T = (100 ± 5)°C.…”

“…Against this background, surface properties of lubricated rolling-sliding contact partners periodically or continuously operating under boundary and mixed friction conditions and the interactions with the lubricant can be considered as the key factors influencing the friction behavior. 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].…”

“…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]. Due to their properties in terms of friction reduction and wear protection, DLC coatings are typically used in dry-running or under boundary and mixed friction conditions [4,5,7,8,11,[16][17][18][19][20][21][22].…”

“…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]. Due to their properties in terms of friction reduction and wear protection, DLC coatings are typically used in dry-running or under boundary and mixed friction conditions [4,5,7,8,11,[16][17][18][19][20][21][22]. But application of these coatings in the fluid friction regime comes into focus of research and development.…”