The rolling contact fatigue of WC/C-coated spur gears

Abstract

The aim of the study was to investigate the resistance to rolling contact fatigue of WC/C-coated gears. The WC/C lowfriction coating was deposited using the physical vapour deposition process by reactive sputtering. The investigation of rolling contact fatigue was realised by means of a back-to-back gear test rig using FZG PT C/10/90 method. Four material combinations of gears were tested: uncoated wheel and pinion, coated wheel and pinion, coated wheel and uncoated pinion, as well as uncoated wheel and coated pinion. The tests were performed for mineral gear oil of API GL-5 performance level and 80 W/90 viscosity grade. The test results indicate that the resistance to the pitting wear of coated gears depends not only on coating material but also on which gear is coated. To increase the fatigue life of gears, the coating should be deposited on the gear with the higher number of teeth. The mechanisms by which the fatigue life is extended are discussed.

Testing of the Resistance to Scuffing of Spiral Bevel Gears: Test Rig, Method, and Results of Verification Testing

“…According to the facts presented by the researchers [17][18][19][20][21][22] who performed scuffing tests on spur gears, there is a possibility to improve the resistance to scuffing of gear elements by deposition of a thin, hard coating, i.e. a-C:H:W, on at least one of the gears.…”

“…The second demand relates to the reduction of friction, leading to the decrease in heat emission, lowering the energy losses, and above all, resulting in a decrease of the tendency to scuffing. The abovementioned effect can be achieved by the deposition of a thin, hard, and low-friction coating on the operating surface of the gears, although the present-day research is limited to spur gears [14][15][16][17][18][19][20][21][22]. The third important aspect is environmental protection, which is addressed by the use of new generation gear oils (ecological-friendly) providing the proper operational properties of the gear.…”

The influence of a CrN+a-C:H:W coating on the development of fretting wear in a model of a wheel–axle press-fit joint on a wheel set of a railway vehicle

“…The third layer, called the external layer, directly mates with the sleeve. According to literature, the atomic composition of this layer is as follows: 12% W, 70% C, 15% H, 3% Ni [15][16]. Nickel is an outcome of the coating generation process.…”

Sliding Wear Performance of AlCrN Coating on TiB2/Ti Composites at High Temperatures

“…To use the benefits provided by coatings and ceramic composites, it is crucial to consider their implementation at the design stage. It is well known that friction and wear characteristics are not intrinsic properties of materials [18], but a result of interactions between surfaces sliding against each other under certain test conditions, additionally highly influenced by an ambient temperature [19,20].…”