Development of X-Shaped Filtered-Arc-Deposition (X-FAD) Apparatus and DLC/Cr Film Preparation

An X-shaped filtered-arc-deposition (X-FAD) apparatus was developed in order to prepare hydrogen-free tetrahedral amorphous carbon (ta-C), which is a kind of diamond-like carbon (DLC), and metal film as a binding interlayer on the superhard alloy using a plasma beam irradiated from the same direction. First of all, the droplet-reduction performance was verified, and then, the appropriate duct-bias voltages and deposition rate were measured. Optima of duct biases for chromium (Cr) and DLC were found to be 25 and 15 V, respectively. From the result of X-ray diffraction analysis, it was found that Cr film that is prepared at a higher substrate-bias voltage was well crystallized and has less internal stress. The appropriate substrate bias for preparing ta-C was -100 to -200 V. DLC film was also prepared with substrate heating. It was found that ta-C could be prepared at a substrate temperature of less than 200degC, and the film was graphitized at higher temperature. By following these results, 2.5-mum-thick ta-C film was prepared on a superhard alloy with an interlayer by X-FAD.