Tungsten Carbide Anvil Description (2/2)

Synthetic diamond process can be specifically divided into two methods, direct and indirect method. Direct method uses instantaneous dynamic temperature and high pressure, high temperature and static two mixed techniques such as graphite as raw material to C directly into the diamond (meet under static pressure> 13GPa, temperature of 2000K and holding time> 1min; under dynamic conditions, pressure> 20 GPa); the indirect method uses static high temperature and pressure technology to react C elements with the specific metal and obtain synthetic diamond (the transition process is molten metal or alloy + graphite <=> C atom + metal atom or group of atoms <=> diamond + metal or alloy and some carbides).

Domestic synthetic diamond industry mainly is based on hexa-orientation anvil, which belongs to static catalyst method. The basic principle is use six tungsten carbide anvil in six surfaces, while the scope of the high-pressure cavity by the pyrophyllite hexahedron composed of such a graphite cavity under the catalytic effect of high temperature and press into a diamond. Pyrophyllite tetrahedron is a hydrous aluminum silicate layered structure, in the process of synthesis plays role in pressure transmission, sealing and insulation effect; Catalyst acts as a catalyst, can effectively promote the synthesis of diamond, and reduce the pressure required for the synthesis temperature, a common catalyst material Ni70Mn25Co5 alloy.

Anvil diameter is generally φ80mm - φ40mm, density 14.70-14.80g / cm3, hardness of about HRA89.5, diameter of the particles (2-3μm). Sintered tungsten carbide anvil service life is about 5,000 times ten thousand karats consumption> 3kg. Compared with the domestic synthetic diamond industry, foreign-related enterprises have begun to adopt YG12x fine particles carbide diamond anvils, hardness generally reach more than HRA90.5, bending strength of 3000MPa, the average service life is more than 8,000 times, ten thousand karats consumption <1.5kg. Therefore, by grain refinement to improve tungsten carbide anvil density, toughness, flexural strength and prolong the service life of, reduce the consumption, which is a inevitable trend anvil of anvil development.

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