W/WC diffusion barrier layers for CVD diamond coatings deposited on WC-Co: microstructure and properties

Abstract

WC films are investigated for use as intermediate layers for adhesion improvement between the cemented carbide (WC-Co) substrate and a CVD diamond wear resistant layer. WC layers are prepared by reactive magnetron sputtering. Deposition conditions during the sputtering are adjusted to change the WC layer stoichiometry and the microstructure. Layers are investigated by X-ray diffraction and scanning electron microscopy (SEM) in as deposited and in annealed states. Adhesion of diamond is investigated by Rockwell-C indentation. Adhesion data shows a strong dependency on the deposition conditions for the WC layers. This data is explained in terms of Co diffusion from the substrate through the intermediate layer and of mechanical properties of the intermediate layer itself. (C) 1998 Published by Elsevier Science S.A.