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

A chemical vapor infiltration, carbon composite material technology, applied in the field of carbon/carbon composite material preparation, can solve the problems of increasing the preparation cost, increasing the transportation cost, difficult operation, etc., to improve market competitiveness, save transportation costs, and reduce production. cost effect

Inactive Publication Date: 2010-02-10
XIAN CHAOMA SCI TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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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 t

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Put the porous carbon fiber prefabricated body into the isothermal and isobaric vacuum deposition furnace, evacuate the vacuum deposition furnace, evacuate the air in the furnace, and keep it for 1h, then set the furnace pressure to 3KPa (that is, the deposition pressure), and vacuum the vacuum deposition furnace When the temperature in the furnace reaches 950°C (that is, the deposition temperature), the temperature is raised by power transmission, and natural gas is introduced to keep the gas residence time at 1 second, and the chemical vapor phase densification treatment is carried out. The main component of natural gas is methane, and methane is the gas with the simplest structure, the highest carbon content, and the best thermal stability among all gas precursors. The formation of crusts is beneficial to shorten the densification cycle of carbon / carbon composites. Natural gas is rich in sources and low in price, which can reduce production costs, and natural gas can...

Embodiment 2

[0018] Put the porous carbon fiber prefabricated body into the isothermal and isobaric vacuum deposition furnace, evacuate the vacuum deposition furnace, evacuate the air in the furnace, and keep it for 1.5h, then set the furnace pressure to 10KPa (that is, the deposition pressure), and the vacuum deposition The furnace is powered up to raise the temperature, and when the temperature in the furnace reaches 1100°C (that is, the deposition temperature), a mixed gas of natural gas and acetylene is introduced, the volume ratio of natural gas and acetylene is 9:1, and the residence time of the mixed gas is kept at 1s to carry out chemical vapor phase densification. treatment. A small amount of acetylene is mixed into the natural gas precursor to reduce the cracking temperature of natural gas and improve the texture of pyrolytic charcoal.

Embodiment 3

[0020] Put the porous carbon fiber prefabricated body into the isothermal and isobaric vacuum deposition furnace, evacuate the vacuum deposition furnace, evacuate the air in the furnace, and keep it for 2 hours, then set the furnace pressure to 25KPa (that is, the deposition pressure). When the temperature in the furnace reaches 1250°C (that is, the deposition temperature), a mixed gas of natural gas and acetylene is introduced, the volume ratio of natural gas and acetylene is 4:1, and the residence time of the mixed gas is kept at 1s for chemical vapor phase densification. deal with. A small amount of acetylene is mixed into the natural gas precursor to reduce the cracking temperature of natural gas and improve the texture of pyrolytic charcoal.

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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...

Claims

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Application Information

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IPC IPC(8): C04B35/645C04B35/83
Inventor 薛宁娟苏君明肖志超彭志刚侯卫权谷立民苑涛
Owner XIAN CHAOMA SCI TECH
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