Nucleation and growth of diamond by different seeding mechanisms on cemented carbide inserts by HFCVD process

An attempt was made to deposit diamond by Hot Filament CVD method on tungsten carbide inserts. The inserts were pretreated with acid solution. This was followed by seeding of the substrates with powders of Ti, Mo, W and diamond separately. Depositions were done at 700 0 C and at a pressure of 20 Torr with CH 4/H 2 flow ratio of 0.5/100 SCCM. Discontinuous diamond film was obtained on the as received carbide surface which did not undergo any pretreatment and seeding. There was no improvement in coating when the acid treated sample was seeded with either of Ti, Mo or W powders. A continuous diamond film with well-developed morphology was deposited when the acid treated carbide surface was seeded with diamond powder.