Tribological properties of graphite-like and diamond-like carbon coatings

Two hard, carbon-based solid lubricant coatings, Graphit-iC((TM)) and Dymon-iC((TM)) have been developed which offer considerable benefits over traditional diamond-like carbon (DLC) coatings. Both have extremely high wear resistance and load-bearing capability, in contrast to many commercial DLCs which tend to be brittle, and very low friction characteristics. The development of the coatings is described, and details of their tribological properties in air and water are given. The structure of the coatings has been studied and related to the tribological properties, and the mechanism for the low friction and wear rates is discussed. The coatings are proving successful in increasing the lifetime and efficiency of many mechanical parts, including automotive fuel injection components, gears, bearings, tappets, gudgeon pins, etc. They offer benefits for tooling, used for forming or machining of soft materials, and are used on dies and moulds. Other application areas include surgical tools and implants. (C) 2004 Elsevier Ltd. All rights reserved.