Abrasion resistant low friction diamond-like multilayers

Over the past few years, we have investigated plasma deposited amorphous hy drogenated carbon (DLC) films modified with B, N and Si dopants. Whereas, a ll three elements have the advantage to induce stress relief in the films ( combined with hardness reduction), Si appeared to be the most interesting a lloying element for tribological applications (friction and wear). Followin g this work, multilayer coatings consisting of a stack of DLC layers altern ated with Si-doped DLC films and more recently, diamond-like nanocomposite (Dylyn (R), a-C:H/a-Si:O) films were developed. A major advantage of the mu ltilayer structure is the stress relief enabling the deposition of thick la yers (10 mum) without any loss of good adhesion properties. These thick mul tilayers show improved abrasion resistance as well as extremely low frictio n properties (friction coefficient <0.1 independent of the relative humidit y). This paper discusses the mechanical and tribological properties of thes e multilayer coatings and presents a comparison to various other layer syst ems (TiN, CrN and hard Cr). (C) 2001 Elsevier Science B.V. All rights reser ved.