Diamond-like Carbon Thin Films Deposited on Ti6Al4V Alloy Surface by Plasma Gun at Atmospheric Pressure

Abstract:

At atmospheric pressure, diamond-like carbon (DLC) thin films were deposited on the Ti6Al4V alloy surface by a DBD plasma gun at low temperature (<350 oC), with CH4 as a precursor and Ar as dilution gas. The structure of the DLC thin film was analyzed by Laser Raman spectroscope and X-ray photoelectron spectroscopy. The surface morphology was observed through scanning electron microscopy. The adhesion between the DLC thin film and the substrate was investigated with the scribe testing. The friction and wear behavior of the DLC thin films under dry sliding against GCr15 steel was evaluated on a ball-on-disc test rig. The results show that it is feasible to prepare a DLC thin film of 1.0 μm thickness by a plasma gun. The film is uniform and dense and the surface roughness Ra is about 13.23 nm. The critical load of adhesion force between the DLC thin film and the substrate is 31.0 N. It has been found that the DLC thin film has excellent friction- and wear-resistant behavior. The friction coefficient of the Ti6Al4V substrate is about 0.50 under dry sliding against steel, while the DLC thin film experiences much abated friction coefficient to 0.15 under the same testing condition.

Key words:DLC film; Ti6Al4V; atmospheric pressure plasma gun; wear resistance