Graphite fiber and preparation method thereof

Abstract

The invention relates to a graphite fiber and a preparation method thereof. The graphite fiber serving as a monomer fiber directly grows by adopting a vapor deposition method under the condition of no catalyst; the purity of obtained products is greater than 99.99 percent; the obtained products are straight and filamentous in appearance, the diameter range is 0.1 to 50mu m and the length range is 3 to 100mm; the products are generally parallel to one another; a hemispherical sealing cover is arranged at the top of each product and the interior of the fiber is solid; Raman spectrum shows that the intensity of a G peak is greater than that of a D peak in the graphite fiber; the graphite fiber has a metallic luster under the irradiation of visible light, and the resistivity of the graphite fiber is equivalent to that of graphite. The graphite fiber uses a quartz plate as a substrate, adopts argon and hydrogen as carrier gases, selects methane as a carbon source, and is prepared by cleaning the substrate, charging into a furnace, carrying out vapor deposition growth and sampling. With a special form and physical properties, the performance consistency between devices can be ensured when the graphite fiber prepared by the method is used for producing vacuum electronic devices such as a cold field emission electric gun filament.

Description

technical field [0001] The invention relates to a graphite fiber and a preparation method thereof, in particular to a graphite fiber prepared under a catalyst-free condition. Background technique [0002] In recent years, various carbon nanomaterials have become research hotspots, such as carbon nanotubes and nanocarbon fibers. Due to its nanometer-scale diameter and micrometer-scale length, as well as good mechanical, electrical, thermal properties and chemical stability, it has high hopes in the fields of engineering materials, microelectronics, micro-electromechanical systems, biology, and medical treatment. However, due to the extremely small scale and large specific surface of carbon nanomaterials, carbon nanotubes have a strong adsorption capacity for each other. Carbon nanotubes prepared by conventional processes are usually entangled and difficult to independently assemble in the designated position of the device. Applications present challenges. Micro-nanoelectron...

AI Technical Summary

Problems solved by technology

At present, the method of applying vapor deposition method to prepare graphite fiber under the condition of no catalyst has not been reported yet, especially the method and product of preparing uniform graphite fiber with straight shape and hemispherical top and length on the macro scale have not been reported. Even though macro-scale carbon nanotube bundles or ropes are prepared by vapor phase growth method, the product is formed by agglomeration of a large number of carbon nanotubes and is not an individualized product

However, the method of using organic fibers to obtain graphite fibers through carbonization and graphitization, due to carburizing and other processes, the fibers are relatively low in graphite lattice integrity and graphitization.

Moreover, when such fibers are cut into the length required by the device, the shape of the top of the individual will inevitably vary greatly and cannot be unified, so it is not suitable for application in vacuum electronics devices.

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