LARGE-SCALE FABRICATION OF HARD SUPERLATTICE THIN-FILMS BY COMBINED STEERED ARC EVAPORATION AND UNBALANCED MAGNETRON SPUTTERING

This paper reports on the mechanical and physical properties of a rang e of TiAlN- and TiN-based polycrystalline superlattice hard coatings f abricated by a combined steered are evaporation and unbalanced magnetr on sputter industrial batch process within a common gas atmosphere. Th e reactive deposition experiments were carried out in a four-cathode s ystem in which the substrates could be continuously rotated at a nomin al target-substrate distance of 250 mm and with variable velocity. The influence of layer composition, deposition technique, substrate rotat ion and coating rate were investigated by XTEM, XRD, RES and Knoop ind entation testing with regard to the superlattice period and microstruc ture, and the preferred orientation and hardness of the coatings. All coatings were found to exhibit fine, highly dense lamella microstructu re, high hardness and excellent adhesion. Film systems deposited by cl osed-field unbalanced magnetron sputtering could exhibit preferred [11 1] growth, whilst coatings deposited by simultaneous steered arc/unbal anced magnetron sputtering generally showed [200] orientation. The per iod of the superlattice could be controlled between 19 and 172 Angstro m by alteration of the substrate rotation and deposition rate. (C) 199 7 Elsevier Science S.A.