Laser-arc technology for industrial hard coating deposition
The Laser-Arc method represents a pulsed vacuum deposition where the arc discharge is ignited by short laser pulses. Owing to the short burning times of the single arcs, the erosion is restricted to the immediate neighbourhood of the ignition point, the laser focus. Hence, the cathode spots may be displayed on the cathode surface according to the displacement of the focus position. In this way, the drawbacks of conventional arc technology such as local overheating and emission of microparticles are essentially reduced. The Laser-Arc has been scaled up from the laboratory level to an industrial prototype. This fully computerized equipment allows the deposition of hydrogen-free diamond-like carbon films of hardness up to 80 GPa with a growth rate of up to 0.2 mu m min(-1). Owing to their low friction and high wear resistance, these films are especially suitable for sliding elements. Such different materials as alloyed and non-alloyed steels, hard metals, copper, aluminium alloys or brass were coated and demonstrated good adherence. The process runs below 100 deg C and allows the deposition on temperature-sensitive materials such as polymers. New fields are opened by the preparation of nanometer-multilayers which are performed by means of this Laser-Arc equipment without any loss in effectivity.