Properties of polymeric layers of hydrogenated amorphous carbon produced by a plasma-activated chemical vapour deposition process II: Tribological and mechanical properties

Review of the tribology of diamond-like carbon

“…Within the experimental error, the friction coefficients of the annealed films were essentially the same as those of the as-deposited films. The insensitivity of the friction coefficients to the annealing temperature was similar to what was observed by Memming et al [18] and Miyoshi [26] in humid air.…”

“…The authors found by Auger electron spectroscopy that, in the conditions of very low friction, carbonaceous material was transferred from the DLC film to the steel rider, while, in the conditions of high friction (in dry oxygen), iron transferred to the DLC surface. The material transfer changed the chemistry of the interface layer and, according to the authors, this 'tribochemical' behavior explained the different values obtained for the friction coefficients under various conditions [18].…”

“…This is explained through a fatigue mechanism which causes the formation and growth of small cracks, leading finally to fracture of the diamond particles. There is also evidence that the debris formed during sliding contributes to the low friction in diamond [18].…”

“…Memming et al [18] studied the tribological behavior of amorphous hydrogenated carbon (a-C:H) deposited by r.f. PACVD from acetylene, toluene or benzene.…”

Study of a-C:H thin films grown by PIII in different times for Mechanical and Tribological applications

“…It is a consistent explanation with Raman analysis, which the layer has a disordered graphite structure, revealing evidence of amorphization of a-C:H films in the wear track. If the hydrogen is removed from hydrogenated DLC, the dangling bonds formed cause strong interactions between the surfaces in contact, resulting in a slope of friction coefficient as function of loss of hydrogen dry hydrogen (35) , similar to that reported for both graphite and diamond (36,37) .…”