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High-thermal-conductivity low-expansion graphite for rocket engine nozzle and preparation method of high-thermal-conductivity low-expansion graphite

A rocket engine and high thermal conductivity technology, which is applied in the field of graphite materials, can solve the problems of large expansion coefficient difference, large graphite brittleness, high graphite density, etc., achieve the performance improvement of low expansion coefficient, increase the degree of graphitization, and improve the effect of thermal conductivity.

Pending Publication Date: 2021-02-05
HUNAN CHANGYU NEW CARBON MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, at home and abroad, C / C ceramic composite materials are a combination of carbon materials and refractory ceramics. Graphite seldom has the conditions to be combined with ceramics. Concentrated on the surface of graphite, graphite is brittle, and its expansion coefficient is different from that of refractory ceramics. It is easy to cause defects such as excessive expansion and graphite cracking during ablation

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037]A high thermal conductivity and low expansion graphite for rocket engine nozzles of the present invention. Its main raw materials are petroleum coke, flake graphite and binder modified high-temperature pitch (softening point 120°C); among them, the quality of petroleum coke powder and flake graphite The ratio is 9:1; the addition amount of modified asphalt is 28% of the total weight (modified high-temperature asphalt + petroleum coke powder + flake graphite powder). The modified high-temperature asphalt is obtained by vulcanizing high-temperature asphalt.

[0038]The preparation method of high thermal conductivity and low expansion graphite for rocket engine nozzles of this embodiment includes the following steps:

[0039](1) Crush the petroleum coke and flake graphite with a shaping machine to two fine powders with a particle size of D50=25μm, and use them for later use (the powder smaller than 10μm and the particles larger than 150μm in the material are removed by sieving during t...

Embodiment 2

[0054]The process of this embodiment is basically the same as that of embodiment 1, except that the mass ratio of petroleum coke powder and flake graphite in step (1) is 8:2; in step (2), the volatile content in the mixture accounts for the total mixture 12.2wt% of mass. The final product pass rate was 91%. After graphite performance testing, its average particle size is 68 microns; the bulk density is 1.90g / cm3, Compressive resistance 79Mpa, Flexural resistance 36MPa, resistivity 11.2μΩ·m, thermal expansion coefficient 2.1*10-6 / ℃, the thermal conductivity is 118W / (m·K). The 10s anti-ablation mass loss rate is 0.11%, and the sample processing cycle of this embodiment is 8 months.

Embodiment 3

[0056]The process of this embodiment is basically the same as that of embodiment 1, the difference is: in step (1), the mass ratio of petroleum coke powder and flake graphite is 7:3, and the volatile content in the mixture accounts for 12wt% of the total mass of the mixture. . The final sample qualification rate exceeded 92%. After graphitization test, the average particle size is 70 microns; the bulk density is 1.85g / cm3, Compression resistance 65Mpa, flexural resistance 32Mpa, resistivity 10.8μΩ·m, thermal expansion coefficient 3.7*10-6 / °C, the thermal conductivity is 115W / (m·K), the ablation resistance mass loss rate is 0.10% in 10s, and the sample processing cycle of this embodiment is 8 months.

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Abstract

The invention discloses high-thermal-conductivity low-expansion graphite for a rocket engine nozzle. The high-thermal-conductivity low-expansion graphite is mainly prepared from petroleum coke powder,crystalline flake graphite powder and modified high-temperature asphalt. The modified high-temperature asphalt is obtained by carrying out sulfur vulcanization treatment on high-temperature asphalt.The preparation method of the graphite comprises the following steps: shaping petroleum coke and crystalline flake graphite, kneading the shaped petroleum coke and crystalline flake graphite with thehigh-temperature modified asphalt, flaking, crushing, standing, carrying out isostatic pressing, carbonizing, dipping, and finally graphitizing to obtain the high-thermal-conductivity low-expansion graphite. According to the invention, the graphite takes the petroleum coke powder as a main material, the crystalline flake graphite as an auxiliary material and the sulfur modified asphalt as a binder, and reasonably matches the types and proportions of aggregates, so that the high thermal conductivity and low expansion coefficient of the graphite can be effectively enhanced while the strength index of the graphite is basically maintained, thereby reducing the expansion coefficient difference between the graphite and refractory ceramic and improving the strength of the refractory ceramic. Rocket engine spray pipe using requirements are met.

Description

Technical field[0001]The invention belongs to the technical field of graphite materials, and particularly relates to a graphite with high thermal conductivity and low expansion for a rocket engine nozzle and a preparation method thereof.Background technique[0002]As a key component of the rocket, the rocket engine nozzle has the function of controlling the pressure of the combustion chamber, maintaining the normal combustion of the charge, accelerating the expansion of the gas, and then converting the heat energy of the gas into kinetic energy. Due to the long-term blockade of my country's military graphite by foreign countries, the current use of military graphite is mainly T series graphite from Harbin Electric Carbon Plant. The graphite has served my country's military industry for decades. From small tactical missiles to medium- and long-range rocket engines, all nozzles are pure graphite structures. There is still a lot of room for growth in the feasibility of graphite matrix mo...

Claims

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Application Information

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IPC IPC(8): C04B35/52C04B35/532C04B35/622
CPCC04B35/522C04B35/532C04B35/622
Inventor 杨程熊红利王新华刘金平吴志刚何成林张习龙黄斌陈帮智陈红李启常陈新征谭征
Owner HUNAN CHANGYU NEW CARBON MATERIALS
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