In order to machine without cooling lubricants, hard coatings having very low dry friction values are necessary as layers on the surfaces of machining tools. They keep friction temperatures low at the very locus where they come into existence so that less heat than normal has to be dissipated. Diamond-like carbon (DLC) coatings serve this purpose best. After a short description of the plasma chemical vapour deposition process, the properties of doped DLC are given followed by three examples of applications concerning machining tools and sliding bearings for chemical pumps. (C) 1999 Elsevier Science S.A. All rights reserved.