Each type of DLC has specific advantages. Some remarkable results are listed below:
l The Si alloyed RF PACVD multilayer and ion beam deposited coatings yield stable, very low friction behaviour under dry sliding conditions.
l 13.56 MHz RF PACVD a-C:H coatings show excellent wear resistance under dry sliding conditions while at the same time protecting the surface of the steel counterbody.
l High load carrying capacity is apparent for the magnetron sputtered a-C:HยฑW multilayer coating, and especially for the PVD C/CยฑCr coating, which should prevent failure under high contact stress.
l As expected, the hard hydrogen free arc discharge a-C coating shows the best resistance against abrasion.
l The low frequency RF DLC coating does not show peak properties under the given test conditions, but offers a combination of good wear resistance, low friction behaviour and considerable load carrying capacity. Evidently, these are the results of only a limited series of tests. Complementary tests are being carried out by the partners in this COST 516 project, and those results will be used to make the picture more complete.
The total of data gathered by all partners in this project should in the future facilitate the selection of the appropriate DLC coating type for a specific application.