Method for quick-speed preparing carbon/carbon composite material using heat gradient chemical gas phase infiltration

Abstract

The invention discloses a method to quick prepare C / C composite material by heat-gradient chemical gas phase permeation, which comprises: using two upper-lower independent graphite heaters on heat-gradient chemical gas phase permeation device to realize boil and gasify the liquid predecessor and provide high-active carbon source for cracking reaction by lower heater; locating the prefabricated body and upper heater on top of predecessor liquid surface by supporting bar and hole-contain supporting board to realize heat the prefabricated body and form heat gradient along its thickness orientation by upper heater; passing long-path convection and diffusion, the gasified carbon source enters the prefabricated body to crack and generate deposition for 4~10h, and obtaining the product with density as 1.6~1.8g / cm3. This invention needs simple devices, has technical parameters easy to regulate, reduces energy greatly, and has wide application.

Description

technical field [0001] The invention relates to a rapid preparation of composite materials, in particular to a method for rapid preparation of carbon / carbon (C / C) composite materials by thermal gradient chemical vapor infiltration using liquid precursor gasification as a carbon source. Background technique [0002] Carbon / carbon (C / C) composite materials have high specific strength, high specific stiffness, high strength at high temperature, good ablation performance, friction performance and good thermal shock resistance, as well as the designability of composite materials. In the aviation field, especially as an aircraft brake material, it has broad application prospects. At present, isothermal chemical vapor infiltration (Chemical vapor infiltration, CVI) is the main method for preparing C / C composites. Although this process has certain advantages, its disadvantages are that the preparation process cycle is too long and the utilization rate of raw...

AI Technical Summary

Problems solved by technology

At present, isothermal chemical vapor infiltration (Chemical vapor infiltration, CVI) is the main method for preparing C / C composites. Although this process has certain advantages, its disadvantages are that the preparation process cycle is too long and the utilization rate of raw materials is low.

[0005] (1) The reaction to form deposited carbon is carried out in a boiling liquid precursor. This process is affected by fluid mechanics, gas-liquid two-phase flow, boiling heat transfer, and complex chemical reactions. It is not only difficult to give an accurate theoretical explanation and calculation, and it is very difficult to realize and control the process parameters in actual operation;

[0006] (2) To make the liquid precursor form a gaseous film in the preform (that is, film boiling) and crack the reaction to generate deposited carbon, a huge heating power is required to ensure that the inside of the preform has a high enough temperature, which causes electric energy A large amount of waste will cause the liquid precursor to boil violently, causing it to be consumed rapidly; and the atmospheric pressure in the reactor exceeds the positive pressure, which has certain dangers;

[0007] (3) During the deposition process, independent control of the temperature of the preform cannot be achieved, nor can the reactants (gas concentration, pressure) be measured and controlled

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