CHEMICAL VAPOR-DEPOSITION OF A DIAMOND COATING ONTO A TUNGSTEN CARBIDE TOOL USING ETHANOL

Diamond coating of a tungsten carbide alloy using the hot filament chemical vapor deposition process was investigated for application to tool manufacture. Previously, diamond deposition onto a cobalt-rich tungsten carbide alloy has been considered to be impossible using this process. However, it was found that using ethanol as the carbon source a good diamond coating layer could be obtained. When a diamond-coated tool was applied to the shearing of an aluminium plate, no abrasion of the diamond coating and no adhesion of chips of the sheared material to the tip of the tool were found even after 5×104 punchings, demonstrating the excellent hard coating effect as well as reasonably good adhesion of the coated diamond layer.