Abstract:Nano/microcrystalline composite diamond films were deposited on the holes of WC-6%Co drawing dies by a two-step procedure using alternative carbon sources, i.e., methane for the microcrystalline diamond (MCD) layer and acetone for the nanocrystalline diamond (NCD) layer. Moreover, the monolayer methane-MCD and acetone-NCD coated drawing dies were fabricated as comparisons. The adhesion and wear rates of the diamond coated drawing dies were also tested by an inner hole polishing apparatus. Compared with mono-layer diamond coated drawing die, the composite diamond coated one exhibits better comprehensive performance, including higher adhesive strength and better wear resistance than the NCD one, and smoother surface (R_a=65.3 nm) than the MCD one (R_a=95.6 nm) after polishing at the same time. Compared with the NCD coated drawing die, the working lifetime of the composite diamond coated one is increased by nearly 20 times.

Key words: microcrystalline; nanocrystalline; composite diamond film; WC-Co drawing die; alternative carbon source