Wear resistant carbon coatings deposited without substrate bias voltage

A DC magnetron sputtering process is described which permits the deposition of highly wear-resistant carbon coatings without substrate bias voltage. The coatings, with a thickness of up to 10 μm, are deposited on several materials such as hardened high-speed steel and ceramics, with typical growth rates in the range of 1.5 μm/h. The main structural feature of the coatings is an amorphous carbon network with dominating graphitic bonding. Despite this structural feature, the coatings exhibit a high wear resistance. The friction coefficient with a hard metal counter body is in the range of 0.1–0.15 and the wear volume is distinctly lower than with other hard coating materials such as a-C:H.