DLC AND METALLIC NANOMETER MULTILAYERS DEPOSITED BY LASER-ARC

The method of laser-induced vacuum are (laser-are) combines the good c ontrollability of pulsed laser deposition with the high efficiency of a vacuum are technique. One advantage of this technique is the:essenti al reduction of droplets allowing the deposition of high-quality amorp hous carbon films. These hydrogen-free films with very high hardness u p to the superhard range exhibit excellent wear resistance and low fri ction. In the present paper, another advantage of the laser-are is dem onstrated, i.e. the possibility of depositing multilayer coatings down to the nanometer level of each individual layer thickness with high e fficiency and high accuracy. These possibilities open new ways to over come the principal problem of hard PVD coatings, i.e. the high interna l stress which restricts the film thickness. Multilayer systems of AI- C and Ti-C with systematic variations of single layer thickness and th ickness relationship were analysed by electron microscopy and Auger el ectron spectroscopy. The Young's moduli were measured by the non-destr uctive ultrasonic surface wave method (US-SAW). The alternating hard a nd ductile layers allowed a remarkable relaxation of the internal stre sses. Furthermore, the growth of the particle induced defects (droplet s) could be strongly reduced. (C) 1997 Elsevier Science S.A.