Tribological properties of a-C:H films coated by the PBII method

Abstract

Amorphous hydrogenated carbon (a-C:H) films were synthesized by the plasma-based ion implantation (PBII) technique using an electron cyclotron resonance plasma source with a mirror field with the simultaneous application of a DC and a pulse bias to the substrate. The influence of the duty ratio of the pulse biasing on the property and the uniformity of the a-C:H films for three-dimensional surfaces were investigated. An a-C:H film with a low friction coefficient (0.02) and low wear rate (6×10 −8 mm 3/Nm) under a high conducted load (20 N) could be formed by the simultaneous application of a pulse (−2 kV) of low duty ratio (1%) and a DC bias (−200 V). The thickness, structure, and friction coefficient of the a-C:H film for the three-dimensional surfaces were very uniform. Furthermore, the deposition of a-C:H films on a drilling tool of high-speed steel was carried out, and a uniform film was obtained, because a uniform plasma was formed around the drilling tool. Finally, the uniformity of the film thickness for three-dimensional surfaces was improved within ±10% in distribution by both the DC biasing and the pulse biasing with a short duration.