Method for synthesizing super-long solid carbon fiber by self-catalyzed chemical vapor deposition

Abstract

The invention discloses a method for synthesizing super-long solid carbon fiber by self-catalyzed chemical vapor deposition. The method for synthesizing super-long solid carbon fiber comprises the steps that firstly, at room temperature, the substrate is placed in a central heating zone of a tubular furnace to exhaust the air in the furnace, hydrogen is added, and the tubular furnace is gradually heated in the atmosphere of hydrogen; secondly, methane gas is taken as carbon source, and hydrogen and argon are taken as carrier gas, the methane gas, hydrogen and argon gas are added into the heated tubular furnace at the same time and heat preserved, and reaction are conducted; thirdly, after the reaction, the addition of methane gas and hydrogen is stopped, argon is next added, and after natural cooling to room temperature, the super-long solid carbon fiber is obtained on the substrate. The method has the advantages that it is not necessary to add metal catalyst, the method is simple in process, low in cost, safe and reliable, the synthetic carbon fiber is very high in purity and the length is up to centimeter level.

Description

technical field [0001] The invention relates to the technical field of preparation of ultra-long solid carbon fibers, in particular to a method for synthesizing ultra-long solid carbon fibers by self-catalyzed chemical vapor deposition. Background technique [0002] Carbon fiber is a high-temperature-resistant and corrosion-resistant fiber material with high strength and modulus. It has both the intrinsic properties of carbon materials and the processability of textile fibers. Excellent thermal conductivity, also has a certain electrical conductivity. In addition to being used as thermal insulation materials, it is generally not used alone. It is mostly added to resins, metals, ceramics, concrete and other materials as reinforcing materials to form composite materials and improve the mechanical properties of composite materials. [0003] At present, chemical vapor deposition technology is an effective method for preparing carbon fibers. In the prior art, the title is "Leng...

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Problems solved by technology

[0005] (1) It is necessary to add iron-containing compounds as catalysts, and there will be a small amount of catalyst impurities in the synthesized carbon fibers, which affects the quality of carbon fibers, and the preparation of catalysts increases the process steps; (2) Iron-containing catalysts are easily destroyed during the reaction process. The amorphous carbon covered by the decomposition of natural gas loses its catalytic effect, and the carbon fiber is difficult to obtain an ultra-long structure, and the number of synthesis is small; (3) when the furnace temperature rises to the highest reaction temperature, the substrate is moved into the furnace; after the reaction, the furnace temperature has not dropped to If the temperature is lower than room temperature, the substrate will be removed, which increases the complexity and difficulty of equipment and operation, and will affect the sealing of the system, increasing the risk factor of the process; (4) The gas sequence and flow ratio distribution are not correct Good, the carbon source utilization rate is not high, which relatively increases the cost

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