Laser cladding of vanadium carbide powder developed an interlayer on AISI D6 steel as a diffusional barrier and to relief thermal residual stress. Laser cladding experiments varied resolution (DPI) and scanning speed (mm/s). CVD diamond deposition on this interface went on by HFCVD technique. The coatings were characterized by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM-FEG) and Raman spectroscopy. Ordered state V8C7 phase prevailed in the interlayer. The thickness of heat-affected zone (HAZ) and Laser Cladding Vanadium Coating (LCVC) were 37 µm and 5 µm, respectively, in the best layer produced. The diamond film showed good quality and morphology. The Raman peak at 1342,13 cm-1 shows the residual stresses level undertaken at the film-substrate interface and the corresponding adhesion, demonstrating the suitability of the VC laser cladding process to CVD diamond films deposition.

AbstractThis paper shows successful hindering of the negative effects of the cobalt binder in the process of coating WC-Co cutting tools with CVD diamond films. The strategy was creating a boron-rich layer on the surface of the WC-Co substrates as an interlayer to block Co migration. The traditional boriding technique was improved by preheating the salt powders and controlling the brittle region thickness in the substrate surface. These procedures produce a tougher surface for diamond growth. Adding CF4 to the gas mixture also enhanced diamond adhesion to the surface. The adhesion of diamond films to WC-Co substrates was evaluated by indentation tests. Samples were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), X-ray Diffraction (XRD) and Raman Scattering Spectroscopy (RSS).