A method for preparing boron nitride nanofibers by arc discharge

Abstract

The invention relates to a method for preparing boron nitride nano-fibres by virtue of arc discharge. The method comprises the following steps: (1) providing an arc discharge chamber, installing an anode and a cathode in the arc discharge chamber, using a mixed electrode prepared from graphite and a boron nitride crystal as the anode, and connecting both of the anode and the cathode with a power supply; (2) vacuumizing the arc discharge chamber to obtain a vacuum chamber, and then charging a working gas; (3) turning on the power supply and carrying out arc discharge, and keeping a discharge voltage and a discharge current stable during the discharge process; (4) after the discharge is concluded, collecting the product at the cathode. The electrodes adopted in the method disclosed by the invention are convenient to prepare and low in cost; an electrode distance fine-adjustment system adopted is capable of continuously controlling the discharge voltage between the anode and the cathode to be a certain value, the arc discharge is stable, the automation degree is high, the operation is easy to control, a metal catalyst does not need to be added, and the obtained boron nitride nano-fibres have higher yield and quality.

Description

technical field [0001] The invention relates to a method for preparing nanofibers, in particular to a method for preparing boron nitride nanofibers by arc discharge. Background technique [0002] Boron nitride nanofibers have a hexagonal crystal structure and electronic properties similar to carbon nanofibers, the difference is that boron nitride nanofibers are composed of sp 2 The hybrid boron and nitrogen atoms replace the carbon atoms in the hexagonal crystal structure of carbon nanofibers. These structural properties make boron nitride nanofibers have high mechanical strength and thermal conductivity properties similar to carbon nanofibers and have different properties from carbon nanofibers. Unique physical and chemical properties. Boron nitride nanofibers have better chemical stability, and their anti-oxidation temperature is as high as 800 degrees Celsius, and they are wide bandgap semiconductors with a band gap of about 5eV. The unique electronic and mechanical pro...

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Problems solved by technology

Therefore, the current arc discharge method generally uses conductive compounds of boron, such as hafnium boride, zirconium boride, etc., as the anode discharge, and nitrogen as the working gas to obtain boron nitride nanofibers or nanoparticles in the discharge product. The disadvantages are that the electrode is expensive to manufacture, the yield of boron nitride nanofibers obtained is small, the reaction control is difficult, and the metal impurities mixed in it are difficult to remove, etc.

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