Process for the manufacture of multi-layered, coated hardmetal parts

摘要

The invention relates to a process for the manufacture of multi-layered wear-resistant CVD- or PVD-coatings applied to hardmetal parts containing WC-Co or WC-Ni, where at least one of the layers is a metal-boronitride layer. According to the invention, the boron concentration in the metal-boronitride layer is maintained below the critical level above which in addition a homogeneous boronitride mixed crystal phase a further phase, particularly a diboride phase is formed. A non-boronic, or only slightly boronic, intermediate layer is employed as a diffusion barrier between the hardmetal and the metal-boronitride layer to limit or prevent the formation of brittle tungsten cobalt boron or tungsten nickel boron phases on the external surface of the hardmetal. The metallic boronitride layer can be applied either as a single layer or in multiple layers alternating with other mechanically resistant layers. The hardmetal part is particularly a cutting insert for machining.