A specific revised HFCVD apparatus and a novel process combining HFCVD and polishing technique were presented to deposit the micro-and nano-crystalline multilayered ultra-smooth diamond（USCD） film on the interior-ho...A specific revised HFCVD apparatus and a novel process combining HFCVD and polishing technique were presented to deposit the micro-and nano-crystalline multilayered ultra-smooth diamond（USCD） film on the interior-hole surface of WC-Co drawing dies with aperture ranging from d1.0 mm to 60 mm.Characterization results indicate that the surface roughness values（Ra） in the entry zone,drawing zone and bearing zone of as-fabricated USCD coated drawing die were measured as low as 25.7,23.3 and 25.5 nm,respectively.Furthermore,the friction properties of USCD films were examined in both dry sliding and water-lubricating conditions,and the results show that the USCD film presents much superior friction properties.Its friction coefficients against ball-bearing steel,copper and silicon nitride balls（d4 mm）,is always lower than that of microcrystalline diamond（MCD） or WC-Co sample,regardless of the lubricating condition.Meanwhile,it still presents competitive wear resistance with the MCD films.Finally,the working lifetime and performance of as-fabricated USCD coated drawing dies were examined under producing low-carbon steel pipes in dry-sliding and water-lubricating conditions.Under the water-lubricating drawing condition,its production significantly increases by about 20 times compared with the conventional WC-Co drawing dies.展开更多
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 a...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（Ra=65.3 nm） than the MCD one（Ra=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.展开更多
基金Project(51005154) supported by the National Natural Science Foundation of ChinaProject(12CG11) supported by the Chenguang Program of Shanghai Municipal Education Commission,ChinaProject(201104271) supported by the China Postdoctoral Science Foundation Special Funded Project
文摘A specific revised HFCVD apparatus and a novel process combining HFCVD and polishing technique were presented to deposit the micro-and nano-crystalline multilayered ultra-smooth diamond（USCD） film on the interior-hole surface of WC-Co drawing dies with aperture ranging from d1.0 mm to 60 mm.Characterization results indicate that the surface roughness values（Ra） in the entry zone,drawing zone and bearing zone of as-fabricated USCD coated drawing die were measured as low as 25.7,23.3 and 25.5 nm,respectively.Furthermore,the friction properties of USCD films were examined in both dry sliding and water-lubricating conditions,and the results show that the USCD film presents much superior friction properties.Its friction coefficients against ball-bearing steel,copper and silicon nitride balls（d4 mm）,is always lower than that of microcrystalline diamond（MCD） or WC-Co sample,regardless of the lubricating condition.Meanwhile,it still presents competitive wear resistance with the MCD films.Finally,the working lifetime and performance of as-fabricated USCD coated drawing dies were examined under producing low-carbon steel pipes in dry-sliding and water-lubricating conditions.Under the water-lubricating drawing condition,its production significantly increases by about 20 times compared with the conventional WC-Co drawing dies.
基金Project(51275302) supported by the National Natural Science Foundation of China
文摘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（Ra=65.3 nm） than the MCD one（Ra=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.
