LASER-ARC TECHNOLOGY FOR INDUSTRIAL HARD COATING DEPOSITION

The Laser-Are method represents a pulsed vacuum deposition where the a re discharge is ignited by short laser pulses. Owing to the short burn ing times of the single arcs, the erosion is restricted to the immedia te neighbourhood of the ignition point, the laser focus. Hence, the ca thode spots may be displayed on the cathode surface according to the d isplacement of the focus position. In this way, the drawbacks of conve ntional are technology such as local overheating and emission of micro particles are essentially reduced. The Laser-Are has been scaled up fr om the laboratory level to an industrial prototype. This fully compute rized equipment allows the deposition of hydrogen-free diamond-like ca rbon films of hardness up to 80 cpa with a growth rate of up to 0.2 mu m min(-1). Owing to their low friction and high wear resistance, thes e films are especially suitable for sliding elements. Such different m aterials as alloyed and non-alloyed steels, hard metals, copper, alumi nium alloys or brass were coated and demonstrated good adherence. The process runs below 100 degrees C and allows the deposition on temperat ure-sensitive materials such as polymers. New fields are opened by the preparation of nanometer-multilayers which are performed by means of this Laser-Are equipment without any loss in effectivity. (C) 1997 Els evier Science S.A.