1, tungsten electrode graphite collapse arc method
This method is a new method for improving the shortcomings of the carbon-carbon arc method and is basically still a method of evaPoration-condensation. The block pure diamond metal (purity > 9.5%) was placed in anode graphite cruciferous, and the tungsten electrode bar was used as the cathode. The arc occurs between the tungsten electrode and the drill block, melting and evaporating the drill metal, and the graphite will also evaporate with a small portion of the molten metal due to high heat. This new method can increase the evaporation of metals and reduce excessive carbon impurities in the product.
2, experimental device
More specifically, the device was placed in a double water-cooled stainless steel vacuum chamber. The nitrogen inlet of the vacuum chamber can control the flow of nitrogen through the arc section to control the size of the resulting nanoparticle.
3, generate products
1) Graphite nanocrystalline diamond grains
Graphite-coated nanocrystalline grains belong to metal-graphite composites. The core of the drilled metal is approximately a spherical nanometer single crystal, covering approximately 8 to 10 layers of graphite. The distance between the layers is 0.34 nL. The graphite-encapsulated nanocrystal geometry may be due to different core materials or manufacturing. There are two types of spherical and polyhedral shapes due to differences in conditions. All diamond-centered diamonds are spherical, and the outer graphite layer is composed of irregularly arranged small pieces of graphite.
2) Carbon impurities
In the black nanopowder collected at the end of each experiment, in addition to the desired final product, there are a number of nanocrystal grains that are not fully coated with graphite, and a large amount of carbon impurities such as fullerenes. , graphite fibers, graphite fragments, amorphous carbon and so on. These carbon impurities will not be removed in subsequent acid-solubilization purification steps, and only the diamond metal that has not yet been protected by graphite will be rapidly dissolved. As a result, the subsequent further purification is extremely difficult. Zhang Lijuan et al. have tried to use a variety of surfactants to disperse all of the nanocrystals and carbon impurities, and then use a powerful magnet to separate the final product from carbon impurities. However, no ideal surfactant was found. Only methanol was found to have a good dispersion effect.
Semi Automatic Printing Machine,Manual Screen Printing Machine,Flat Printing Machine,Foil Stamping Machine,Semi Automatic Printer,Manual Screen Printer,Flat Printer,Foil Stamping Equipment
GIG (DONGGUAN) CO., LTD , https://www.decorationmachine.com