A method for filling activated carbon in carbon fiber prefabricated body and its application

Abstract

The invention belongs to the technical field of preparation of high-reactivity C / C prefabricated bodies, in particular to a method for filling activated carbon in carbon fiber prefabricated bodies and its application. Dry the liquid aminophenol-formaldehyde resin to remove part of the solvent, then dissolve it in an organic solvent in a certain proportion, make a resin solution with a small amount of additives or no additives, impregnate the carbon fiber preform in the resin solution, and place it in an oven In-situ cross-linking polymerization at normal pressure; the polymerized product is taken out, washed with ethanol, dried, and pyrolyzed under vacuum or inert atmosphere to obtain a porous C / C composite material. The density of the composite material can be adjusted by repeated dipping times. The C / C composite material prepared by the method of the invention has good reaction performance with silicon and silicon alloys, and the C / SiC composite material with high performance and low cost can be prepared through reaction infiltration.

Description

technical field [0001] The invention belongs to the technical field of preparation of high-reactivity C / C prefabricated bodies, in particular to a method for filling activated carbon in carbon fiber prefabricated bodies and its application. Background technique [0002] C / SiC ceramic matrix composites have the advantages of high specific strength, high specific modulus, low density, high thermal conductivity, low thermal expansion and good thermal shock resistance, and can be widely used as thermal protection, thermal structure and friction braking materials Aerospace, energy, transportation and other fields. In addition, C / C composite materials have the characteristics of high specific strength, low density, low thermal expansion coefficient, and excellent high-temperature mechanical properties, and are regarded as one of the key materials in the aerospace and national defense fields. However, this material is prone to oxidation and ablation in the environment of high-temp...

AI Technical Summary

Problems solved by technology

In the CVI process, due to the concentration gradient of the silicon-containing gas, the deposition rate outside the preform is greater than that inside the preform, so crusting occurs, and the surface of the preform needs to be processed multiple times to open the pores before proceeding. Deposition, resulting in an increase in the process, prolonging the preparation cycle, and increasing the production cost

The disadvantages of the PIP process are the high cost of raw materials, and the low cracking yield of the precursor, which requires repeated immersion-cracking to achieve densification

However, the biggest problem faced by the existing LSI process is that the amount of SiC generated after reaction sintering is small, and a large amount of silicon and carbon remain in the composite material. reduced performance

At the same time, due to the large amount of silicon remaining in the composite material, its use temperature is also limited.

[0004] In order to solve the problem of poor mechanical properties of C / SiC composite materials in the LSI process, the Institute of Metal Research, Chinese Academy of Sciences invented "a reactive infiltration process for C / SiC composite materials (application number 201318009258.4)", which uses solvothermal technology. The method of preparing activated matrix carbon in the carbon fiber prefabricated body makes the matrix carbon react completely with liquid silicon, eliminates residual carbon, reduces residual silicon content, reduces the reaction temperature at the same time, reduces the thermal damage and chemical damage of carbon fiber itself, thereby greatly improving LSI Mechanical Properties of C / SiC Composites Prepared by Process

However, in the activated carbon filling process of this process, the polymerization temperature of the resin is 100-240°C. At this time, the internal pressure of the reactor is 0.3-6MPa. The high operating pressure not only brings production safety risks, but also the enlargement of the high-pressure vessel is extremely inconvenient. Bottlenecks restricting the scale-up of the process

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