c/c-sic composite material and its preparation method and application

Abstract

The invention discloses a C / C-SiC composite material, and a preparation method and an application thereof. The C / C-SiC composite material comprises a carbon fiber prefabricated part, a carbon matrix and a silicon carbide matrix, aperatures of the carbon fiber prefabricated part are filled with the carbon matrix and the silicon carbide matrix, the silicon carbide matrix comprises a first silicon carbide matrix and a second silicon carbide matrix, and the second silicon carbide matrix is introduced through a vapor silicon infiltration sintering technology. The preparation method comprises the following steps: 1, introducing the carbon matrix; and 2, respectively introducing the first silicon carbide matrix and the second silicon carbide matrix. The C / C-SiC composite material has the advantages of uniform components, high density, fine matrix particles, high friction stability, high heat conductivity and excellent mechanical performances. The preparation method is simple, and the composite material has excellent performances.

Description

technical field [0001] The invention belongs to the field of carbon fiber reinforced ceramic matrix composite materials, and in particular relates to a C / C-SiC composite material and its preparation method and application. Background technique [0002] C / C-SiC (carbon ceramic) composite material combines the advantages of C / C composite material and SiC, with low density, wear resistance, high friction coefficient, smooth braking, corrosion resistance, oxidation resistance, high temperature resistance, environmental adaptability It is an ideal new type of high-performance friction material due to its advantages of strong (such as friction factor does not decline in wet state) and long life. [0003] In the prior art, the preparation steps of carbon-ceramic composite materials mainly include: (1) The preparation of porous C / C composite materials mainly adopts chemical vapor infiltration (Chemical vapor infiltration, CVI) method or precursor impregnation-cracking (Precursor inf...

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Problems solved by technology

[0004] The above preparation methods still have the following problems in practical application: (1) On the basis of the porous C / C composite material, when the SiC matrix is ​​introduced by the CVI method, because the CVI method cannot obtain a completely dense carbon-ceramic composite material, the obtained The C / C-SiC composite material has a porosity of about 10Vol%. The existence of porosity reduces the thermal conductivity of the composite material, resulting in the thermal conductivity of the obtained carbon-ceramic composite material being generally less than 20W / m·k, which cannot meet the requirements of high energy consumption. The requirements for the use of load brakes (the thermal conductivity of the carbon-ceramic composite material is required to be greater than 40W / m K); (2) On the basis of the porous C / C composite material, when the SiC matrix is ​​introduced by the LSI method, although a completely dense The composite material, but the residual Si with a volume fraction exceeding 5% will remain in the composite material, and the hardness of the residual Si is less than that of SiC, which will be gradually worn away during the friction process, leaving pits in the composite material, and the formation of pits will be intensified The wear of the brake pads affects the service life of the material. In addition, the residual Si will oxidize and wear during the friction process to form molten SiO 2 , resulting in an adhesion effect, reducing the friction stability of the material, and even causing the brake pads to stick together and lock; (3) when the SiC matrix is ​​introduced by the LSI method alone, since the temperature of the LSI process is greater than 1450 ° C, the SiC matrix obtained by the reaction The particle size is large, and the coarse particle SiC will accelerate the wear of the friction plate during the friction process, and will also affect the service life of the material; (4) The concentration of liquid Si used in the LSI method is high, and the reaction speed of Si and C in the initial stage of the reaction is too fast and It is difficult to control, resulting in the rapid formation of closed pores on the surface of the prepared carbon-ceramic composite material, and the Si in the late stage of the reaction cannot penetrate into the composite material to participate in the reaction. The infiltration of silicon on the surface and inside of the carbon-ceramic composite material is not uniform, resulting in The composition is not uniform, and the problem of easy cracking during use

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