Preparation method of novel high-strength heat-dissipation aviation composite material

Abstract

The invention discloses a preparation method of a novel high-strength heat-dissipation aviation composite material. The preparation method of the high-strength heat-dissipation aviation composite material comprises the following steps that a carbon fiber preform is manufactured into a hollow rotating body structure, the ends of the two axial sides of the rotating body are blocked through graphiteclamps, then hydrogen and methyltrichlorosilane gas are introduced into the rotating body, and silicon carbide are generated through chemical vapor infiltration and deposition; in the reaction process, argon is introduced into the carbon fiber preforms, so that an argon pressure pulse is formed; a compact carbon / silicon carbide composite material is prepared, and the obtained material is placed into a mold of a die-casting machine; and afterwards, the die-casting mold is placed into a heating furnace so as to be preheated, an aluminum ingot is placed into the heating furnace to be completely molten, heat preservation and cooling are conducted, and then the compact novel high-strength heat-dissipation aviation composite material is obtained through demolding formation. According to the preparation method, the preparation process is simple, the cost is reduced, and the production efficiency is remarkably improved; and the prepared novel high-strength heat-dissipation aviation composite material can be widely popularized easily.

Description

technical field [0001] The invention relates to a new heat dissipation composite material, in particular to a preparation method of an aviation high-strength heat dissipation composite new material, and belongs to the technical field of ceramic matrix composite materials. Background technique [0002] Carbon / silicon carbide composite materials mainly use carbon fiber braids as reinforcements and silicon carbide as the matrix. They are widely used in aviation, rockets, With the development of science and technology, carbon / silicon carbide composite materials play an increasingly important role in atomic energy, machinery and chemical industries. [0003] At present, for the manufacture of carbon / silicon carbide composite materials, the chemical vapor infiltration method (CVI method for short) is usually used. The CVA method of manufacturing carbon / silicon carbide composite materials is to put the carbon fiber prefabricated body into a high-temperature furnace after being shap...

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Problems solved by technology

[0004] 1. The permeation driving force of the reaction gas is low, resulting in the limitation of the permeation rate: the driving force of the gas permeation depends on the pressure gradient of the gas along the thickness direction of the fiber preform, and the low permeation rate is the bottleneck that limits the increase of the CVI densification speed

In the ICVI process, the transmission of gas depends on diffusion, which shows a very slow permeation rate; in the FCVI process, the driving force of gas permeation is achieved by increasing the pressure (or pressure gradient) of the reaction gas, which is affected by the process and equipment. Influencing factors of safety, the gas pressure can only be increased very limitedly (0.2MPa), and the increase of the permeation rate is limited

[0005] 2. It is difficult to effectively match the penetration rate and the deposition temperature, which affects the densification rate of the composite material: because increasing the deposition temperature of the silicon carbide substrate is a necessary condition for increasing the densification rate, but at the same time it is restricted by the gas permeation rate of the reactant

Since the existing CVI processes have failed to achieve a breakthrough in increasing the gas permeation rate, it is impossible to increase the densification rate of the composite material by increasing the deposition temperature

[0006] 3. The performance stability of composite materials is low: due to the strong historical correlation of the chemical vapor infiltration process, the existing CVI processes do not take into account the historical correlation in the mass transfer process and the chemical reaction process. The size and distribution of the pores inside the fiber preform also change continuously, the concentration of the reactant gas decreases along the depth direction of the pores, and the concentration of by-products increases continuously, which makes the atmosphere in the CVI process uncontrollable and even hinders the chemical reaction and densification. progress, which in turn affects the process of composite material preparation, resulting in low performance stability of composite materials

[0007] 4. During the CVI process, the process will seriously corrode the vacuum pump and increase the equipment cost: during the densification process of the composite material, the chemical reaction of the reactant gas composed of monomethyltrichlorosilane and hydrogen will produce by-products that seriously corrode the vacuum pump, resulting in an increase in equipment cost

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