Growth effects in carbon coatings deposited by magnetron sputtering

Hard amorphous carbon (a-C) coatings were deposited by DC magnetron sputtering from graphite targets by applying different growth conditions. Depending on the process parameters special growth effects and morphologies were observed and analysed by scanning electron microscopy. The constitution and selected properties of the coatings were characterised by Raman spectroscopy, and by measurements of the Vickers hardness and the critical load of failure in the scratch test. A method for the high-rate deposition of hard a-C coatings (Vickers hardness up to 1400 HV0.05, deposition rate up to 1 μm/h, thickness up to 5 μm) with a very low defect density, and dominated mainly by sp2-bondings, is presented. The properties and the morphology of the coatings are discussed with respect to the applied growth conditions.