Method for modifying carbonized pre-oxidized fiber preform interface by carbon nanotube

Abstract

The invention relates to a method for modifying a carbonized pre-oxidized fiber preform interface by a carbon nanotube. The method comprises the following steps: (1) performing carbonization at a set heating rate in a carbonizing furnace under the conditions of vacuum and six temperature sections (room temperature to 200 DEG C, 200 to 350 DEG C, 350 to 400 DEG C, 400 to 600 DEG C, 600 to 650 DEG C and 650 to 1,000 DEG C; (2) firstly removing colloid on the surface of carbon fiber at 600 to 800 DEG C, and then removing impurities on the surface of the fiber with the mixed acid of nitric acid and sulfuric acid; (3) firstly placing a processed carbon fiber punched preform into an organic solution of a catalyst precursor, and then growing the carbon nanotube in situ in a chemical vapor deposition furnace; (4) densifying the preform by a chemical vapor deposition process, and depositing the densified preform for 200 to 350 hours to ensure that the density of the preform reaches 1.70 to 1.75 g / cm3; and (5) placing materials in the vacuum carbonizing furnace, heating the materials until the temperature reaches 2,000 to 2,300 DEG C at the heating rate of 30-50 DEG C per hour under the protection of nitrogen, argon and the like, and keeping the temperature for 3 to 5 hours to obtain a finished product.

Description

technical field [0001] The invention provides a method for modifying the interface of a carbonized pre-oxidized silk prefabricated body by carbon nanotubes, and belongs to the technical field of carbon-based composite materials. Background technique [0002] Carbon-based composite materials have been successfully used in missile nose cones of strategic nuclear weapons, nozzle throat linings of rocket engines and aircraft brake discs due to their good ablation resistance, thermophysical properties, friction and wear properties, and high-temperature mechanical properties. and other aerospace fields. The use of carbon-based composite materials as structural materials for high-temperature and long-term use in the manufacture of hot-end parts of aero-engines is the research and development direction of advanced countries in the world. Carbon-based composites are considered as high-temperature key materials. However, due to the high price of carbon-based composite material raw m...

AI Technical Summary

Problems solved by technology

However, carbon fiber is mainly used in my country. Because carbon fiber is used as needle felt, it is easy to cause fiber breakage and needle breakage. The preparation process is complicated and the cost is high. The modulus of pre-oxidized silk is low, and it is not easy to break during the needle punching process. The use of pre-oxidized filaments as raw materials for preforms has become the main trend in the preparation of high-performance carbon-based composites

However, the use of polyacrylonitrile-based pre-oxidized fiber preforms to prepare carbon-based composites has just started in China. There are few studies on the influence of pre-oxidized fiber structure and carbonization process on the structure and properties of carbon fibers, and there is no guarantee that pre-oxidized fiber can be produced. The prefabricated body obtains a high-performance carbon fiber prefabricated body, therefore, the surface modification of the pre-oxidized silk prefabricated body is very important to obtain a high-performance carbon-based composite material

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