Patent ID: 6890655
Filing Date: 2005-05-10
Classification: B22F,C23C,Y10T

Abstract:
1. A diamond coated cutting tool produced by a process comprising the steps of: providing a sintered substrate, the sintered substrate comprising tungsten carbide and cobalt, the sintered substrate having an average tungsten carbide grain size of between about 3 micrometers and about 20 micrometers; re-sintering the sintered substrate to produce a re-sintered substrate, the re-sintered substrate having a surface and the re-sintered substrate having a surface region beginning at and extending inwardly from the surface, the re-sintered substrate having a bulk region inwardly of the surface region, and the surface region of the re-sintered substrate having an average tungsten carbide grain size of between about 12 micrometers and about 60 micrometers, the bulk region of the re-sintered substrate having an avenge tungsten carbide grain size of between about 3 micrometers and about 20 micrometers, and wherein the average tungsten carbide grain size in the surface region is greater than the average tungsten carbide grain size in the bulk region; subjecting the re-sintered substrate to a chemical treatment for the removal of cobalt at the surface of the re-sintered substrate to produce a treated substrate; and adherently depositing a diamond coating to at least a portion of the surface of the treated substrate.