Method for chemical gas-phase permeation compaction of carbon/carbon composite material

Abstract

The invention discloses a method for the chemical gas-phase permeation compaction of a carbon / carbon composite material. The method comprises the following steps: putting a porous carbon fibre prefabricated body into a vacuum deposition furnace, vacuumizing the vacuum deposition furnace, keeping the vacuum, then setting furnace pressure and furnace temperature, introducing natural gas or the mixedgas of the natural gas and acetylene as a gas precursor body, keeping the gas precursor body being remained in the vacuum deposition furnace and carrying out isothermal isopiestic chemical gas-phasecompacting processing, wherein the volume ratio of the natural gas to the acetylene is 4-9:1. The invention has simple technology, low cost, high carbon deposition efficiency and large permeation depth, is not easy to generate an incrustation on the surface of the carbon / carbon composite material and is beneficial to shortening the compaction period of the carbon / carbon composite material.

Description

technical field [0001] The invention belongs to the technical field of preparing carbon / carbon composite materials, and in particular relates to a method for chemical vapor phase infiltration of dense carbon / carbon composite materials. Background technique [0002] At present, when preparing carbon / carbon composites in China, propylene is usually used as a gas precursor for CVI densification. When propylene is used as the precursor, there are the following disadvantages: (1) propylene is obtained by thermal cracking of petroleum, and the price is relatively high; (2) the molecular weight of propylene is large, the penetration depth is small, and the carbon deposition efficiency is low. / The surface of the carbon material is easy to crust, which requires an intermediate machine and shelling treatment, which prolongs the preparation cycle and increases the preparation cost; (3) Propylene needs to be transported by tank truck, which increases the transportation cost. Therefore...

AI Technical Summary

Problems solved by technology

When propylene is used as the precursor, there are the following disadvantages: (1) propylene is obtained by thermal cracking of petroleum, and the price is relatively high; (2) the molecular weight of propylene is large, the penetration depth is small, and the carbon deposition efficiency is low. / The surface of the carbon material is easy to crust, which requires an intermediate machine and shelling treatment, which prolongs the preparation cycle and increases the preparation cost; (3) Propylene needs to be transported by tank truck, which increases the transportation cost

Using pressure gradient CVI (chemical vapor infiltration) technology, carbon / carbon composite materials with high density can be prepared in a short period of time, but this method requires high equipment and is difficult to operate