Research On Nano-carbon Composite Materials Deposited On Hardmetal By Diffusion Flame Method

Nano-carbon composite materials of high properties such as nano-diamond,carbon nanofibers and carbon nanotubes have been synthesized on YG6 hardmetalsurface using liquid ethanol diffusion flame originally. The morphologies,compositions and microstructures were characterized via optical microscope, SEM,XRD and Raman spectroscopy. The formation rules of these nano-carbon compositematerials deposited in ethanol diffusion flame and the effects of various surfacepretreatment methods on flame-deposited materials were primarily discussed.In the present experiment, a common laboratory alcohol burner was used as thecombustion apparatus to provide a flame, and the vertical height between the top of thewick and the sample was 4.5 cm with 1 cm wick out of the lamp mouth, the pretreatedsubstrate surface was faced down against the flame when it was inserted into thecentral core of the inner flame for 30 min and 60 min respectively.Dipping pretreatment is fit for a batch production due to its simple process andlow cost. For YG6 hardmetal, nano-crystalline graphite was deposited on the originalsubstrate. One-step acid etching couldn't remove Co on the substrate surfaceeffectively and deeply, the flame-deposited materials were mainly nano-diamond andgraphite. Two-step treatment method could etch WC by Murakami reagent firstly andthen etch Co by acid, spherical nano-diamond of high quality was obtained.A pure plating Ni layer of 20 pan depth was induced to improve the adhesion ofcarbon nano-materials coatings deposited by diffusion flame method on YG6hardmetal. Under the same flame techbological condition, carbon nanofibers weresynthesised on the directly nickel-plated substrate. Carbon nanotubes of the smallerdiameter were synthesised on the substrate pretreated by dilute nitric acid dipping andnickel palting.