Installation of gas-phase synthesis of diamond materials based on high-current glow discharge.
Development of a pilot plant for gas-phase synthesis of diamond-like carbon materials
The combination of a number of unique physical properties of diamond materials makes their use promising in many industries from materials processing to electronics and nuclear energy. To date, these applications have been hampered by the relatively high cost of producing both natural and synthetic diamonds, which increases sharply as product sizes increase.
The gas-phase synthesis method does not require the creation of high pressures; in addition, deposition from the gas phase can be carried out over a sufficiently large area and carbon materials with a polycrystalline diamond structure can be obtained on substrates made of molybdenum, tungsten, silicon and other materials. In contrast to the method of synthesizing polycrystalline diamond materials under high pressure and high temperature conditions (HPHT), in the gas-phase synthesis method the resulting diamond materials do not contain a metal binder, i.e. are pure carbon diamond materials and as a result they have high resistance to chemical influences, high thermal conductivity and resistance to abrasive wear. As can be seen from the parameter comparison table below, gas-phase diamond materials are close to single-crystalline materials in their main parameters and are superior to polycrystalline diamond materials obtained using the HPHT method.
In the proposed project, the creation of conditions for gas-phase synthesis is supposed to be carried out in a gas discharge in a mixture of carbon-containing gas (for example, CH4 methane) and hydrogen. To date, the Institute of Nuclear Research of the Russian Academy of Sciences has developed a method for excitation of a pulsed high-current glow discharge and a system for preparing and regenerating a gas mixture, which makes it possible to maintain the parameters necessary for the synthesis of diamond materials in the experimental setup for a long time. An important advantage of the gas-phase synthesis method is its environmental friendliness, because Only environmentally friendly substances are involved in the entire process.
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Comparison table of parameters of diamond materials
GFS - obtained in gas-phase synthesis Mono - single-crystalline natural and synthetic diamonds HPHT - polycrystalline diamond materials obtained by synthesis at high pressures and high temperatures |
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| Property |
GFS |
Mono | HPHT |
| Hardness(GPa) | 85-100 | 85-100 | 50 |
| Young's modulus(GPa) | 1000-1100 | 1000-1100 | 700-800 |
| Compressive Strength (GPa) | 9,0 | 9,0 | 7,6 |
| Thermal conductivity At 20 °C (W/mK) | 500-2200 | 600-2200 | 500-600 |