An improved diamond-like carbon coating with exceptional wear properties

Abstract

Parameters for the deposition of diamond-like carbon thin films using a hybrid magnetron sputter/plasma-enhanced chemical vapour deposition (PECVD) system have been optimised in order to improve the properties for high load-bearing applications. An extensive tribological testing program has been carried out. The main results from this testing program are described. A typical unlubricated pin-on-disc test in air using a 5-mm-diameter WC–Co pin under a load of 100 N gave a specific wear rate of 9×10−18 m3 N−1 m−1 and a coefficient of friction of 0.02. Extremely low counter-surface wear was also observed. Dry cold forming simulation tests, carried out using coated WC–Co balls against tin, indicate much lower friction than for uncoated carbide tools under the same conditions. Due to these properties, the coatings are considered to be suitable for a wide range of industrial applications. Some current applications are described.