PBII deposition of thick carbon coatings from a cathodic arc plasma

We report that we are able to deposit thick carbon coatings on silicon substrates. To date, low-intrinsic-stress, strongly adherent coatings in excess of 11 μm (11 000 nm) have been attained, with no indication that this thickness is an upper limit. Nano-indentation studies indicate that the films have a highly elastic response. Similar carbon films deposited at a standardised thickness of 2000 nm on Ti4Al6V alloy show promising tribological properties in pin-on-disc wear testing. Varying deposition and implantation parameters produce carbon films with radically different wear rates and coefficients of friction. Cross-sectional transmission electron microscopy (TEM) examination reveals layer structures. Electron diffraction images and electron energy-loss spectroscopy (EELS) studies of the first volume plasmon and the K-edge structures suggest a mix of amorphous and graphitic carbon. One of the films demonstrated high impact resistance and exceptionally good performance in pin-on-disc wear testing under aqueous conditions in the presence of electrolytes. The impact and wear resistance of the film is high, whilst its hardness is low. We attribute the good performance to the low friction coefficient, very low intrinsic stress and interface mixing caused by the PBII technique.