An overview on tailored tribological and biological behavior of diamond-like carbon

Diamond-like carbon (DLC), also known as amorphous hydrogenated carbon (a-C:H), is a class of material with variable properties. Depending on the deposition conditions and the setup used in tribological experiments, varying and even controversial results are obtained. Additionally, hydrogen, oxygen and the relative humidity have a crucial influence on the tribological behavior. The amorphous nature of a-C:H opens the possibility to introduce different amounts of other elements into the coating and still maintain the amorphous phase of the coating. By this technique film properties such as thermal stability, hardness, tribological properties, electrical conductivity, surface energy and biological reactions of cells in contact with the surface can be tuned within a certain range. Commercial applications of DLC and alloyed DLC are for example: magnetic storage media, diesel injection pumps, sliding bearings, car valve rockers, gears, tappets of racing motorcycles, laser barcode scanner windows in supermarkets, VCR head drums, textile industry parts. DLC has excellent tribological properties in technical applications, however, the literature shows contradicting results on the wear behavior of DLC-coated hip joints. (C) 2003 Elsevier Science B.V. All rights reserved.