Published Paper Details:

In this paper, an attempt is made to deposit microcrystalline diamond films by Hot Filament Chemical Vapour Deposition (HFCVD) method on Co-cemented tungsten carbide cutting inserts. To restrict the catalytic effect of cobalt binder phase for the formation of non-diamond carbon phases such as graphite and improve the adhesion between diamond and WC, inserts were pretreated with combined HCL and HNO3 solution. Seeding of the substrates was followed separately with Ti, Mo, W and diamond powders. Depositions were done at a pressure of 2.666 kPa, substrate temperature of 7000C, and filament temperature of 21000C with constant CH4 / H2 flow ratio of 0.5 / 100 SCCM. Characterization and purity (sp3 / sp2) of the acquired coatings have been evaluated by Scanning Electron Microscope (SEM) and Raman Spectroscopy. It is observed that there was no improvement in coating morphology when the treated samples were seeded with Ti, Mo or W powders. These results suggested that a continuous diamond film with well facet morphology is deposited with acid treated sample surface seeded with diamond powder. During dry machining, compare to uncoated tool, HFCVD diamond coated tool exhibits remarkable inertness towards aluminium leading to substantial reduction of cutting force and improved work-piece surface finish.