MICROHARDNESS AND ADHESION MEASUREMENTS OF REACTIVELY SPUTTERED TIN ALN MULTILAYER COATINGS DEPOSITED AS FUNCTION OF MASS-FLOW OF NITROGEN/

Multilayer coatings of (Ti, Al)N-x have been deposited by reactive spu ttering from Ti and Al targets in a side-by-side configuration on WC a nd stainless steel substrates. The rotation of the substrate holder va ried from 2 to 14 r.p.m. corresponding to a bilayer thickness of 0.8-8 nm. The acoustic emission scratch technique for adhesion measurements was used for studying coating performance, and critical load values f or the coatings on WC substrate up to 150 N were obtained. The Vickers microhardness in the load range 0.003-2 N was measured, and in order to obtain true hardness values, an optimal range of indentation depth and coating thickness was determined. Depending on the nitrogen flow r ate and bilayer thickness, hardness values of 18-23 GPa were obtained at the film surface. (C) 1998 Elsevier Science S.A.