Method for rapidly densifying high-density full-gaseous phase pyrolytic carbon-based carbon/carbon composite materials

A carbon composite material, gas phase pyrolysis technology, applied in the field of carbon/carbon composite material preparation, can solve the problems affecting the density and uniformity, reduce the wear resistance of C/C materials, etc., and achieve convenient operation and simple process method Effect

Inactive Publication Date: 2010-12-15
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The existence of this difference directly affects the density and uniformity of the solid self-lubricating film on the friction surface of the C / C material during friction braking, thereby reducing the wear resistance of the C / C material

Method used

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  • Method for rapidly densifying high-density full-gaseous phase pyrolytic carbon-based carbon/carbon composite materials
  • Method for rapidly densifying high-density full-gaseous phase pyrolytic carbon-based carbon/carbon composite materials
  • Method for rapidly densifying high-density full-gaseous phase pyrolytic carbon-based carbon/carbon composite materials

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] See attached figure 1 , using quasi-3D needle-punched carbon fiber integral felt, the felt body density is 0.3g / cm 3 , densified to 1.50g / cm by CVI 3, turn it, and the processed sample size is a cylindrical prefabricated body with an outer diameter of Φ50mm and a thickness of 25-30mm. The cylindrical mold 7 is used as a hot-pressing mold, and the mold is heated to 2300-2400℃ , loaded at a loading rate of 60-70MPa / h to 40-45MPa, controlling the strain in the pressing direction to 7%, and gradually unloading at an unloading rate of 30-40MPa / h after holding the pressure for 5-6 minutes; cooling with the furnace to obtain The main performance indicators of the test piece are as follows:

[0024] Density≥1.75g / cm 3

[0025] Graphitization degree≥72%

[0026] Thermal conductivity (⊥)≥45W / m·k

[0027] Shear strength (⊥)≥15MPa

[0028] Compressive strength (⊥)≥135MPa

Embodiment 2

[0030] See attached figure 1 , using quasi-3D needle-punched carbon fiber integral felt, the felt body density is 0.35g / cm 3 , densified to 1.60g / cm by CVI 3 , turn it, the size of the processed sample is a cylindrical prefabricated body with an outer diameter of Φ50mm and a thickness of 25-30mm. The cylindrical mold 7 is used as a hot pressing mold, and heated to 2500℃~2600℃ after the mold is installed. , loaded at a loading rate of 70-80MPa / h to 30-35MPa, the strain in the pressing direction is controlled to be 7%, and the pressure is maintained for 9-10 minutes and then gradually unloaded at an unloading rate of 30-40MPa / h; cooled with the furnace, the obtained The main performance indicators of the test piece are as follows:

[0031] Density≥1.80g / cm 3

[0032] Graphitization degree≥76%

[0033] Thermal conductivity (⊥)≥50W / m·k

[0034] Shear strength (⊥)≥13MPa

[0035] Compressive strength (⊥)≥135MPa

Embodiment 3

[0037] See attached figure 2 , using quasi-3D needle-punched carbon fiber integral felt, the felt body density is 0.4g / cm 3 , densified by CVI to 1.65g / cm 3 , turn it, and the size of the processed sample is an annular prefabricated body with an outer diameter of Φ50mm and a thickness of 25-30mm. The cylindrical mold 7 is used as a hot pressing mold, and the core is inserted in the ring of the test piece. Shaft 19 is molded and heated to 2600°C-2700°C, loaded to 45-50MPa at a loading rate of 90-100MPa / h, controlled to 7% strain in the pressing direction, and held at 30-40MPa / h for 7-8 minutes. The unloading rate is gradually unloaded; with the furnace cooling, the main performance indicators of the prepared test piece are as follows:

[0038] Density≥1.85g / cm 3

[0039] Graphitization degree ≥ 80%

[0040] Thermal conductivity (⊥)≥40W / m·k

[0041] Shear strength (⊥)≥12MPa

[0042] Compressive strength (⊥)≥130MPa

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Abstract

The invention relates to a method for rapidly densifying high-density full-gaseous phase pyrolytic carbon-based carbon / carbon composite materials, comprising the following steps of: densifying a 2D or quasi-3D prefabricator to 1.50-1.70 g / cm<3> by using the conventional CVI (Chemical Vapor Infiltration) to obtain carbon / carbon composite materials using full-coarse layer structure pyrolytic carbon as base carbon; then pressurizing to 30-50 MPa step by step after heating the carbon / carbon composite materials to 2300 DEG C-2700 DEG C, controlling the strain of a pressing direction not to be greater than 8%, and unloading step by step after keeping the pressure for 5-10 minutes; and cooling carbon / carbon workpieces along with a furnace to obtain the carbon / carbon composite materials with the density not less than 1.8 g / cm. The method has the advantages of simple process and convenient operation, is used for rapidly densifying the C / C composite materials through high-temperature hot pressing on the basis of the full-gaseous phase pyrolytic carbon-based carbon / carbon composite materials, is especially suitable for manufacturing high-performance C / C composite aviation brake discs, and is also suitable for manufacturing carbon ceramic composite material disc parts in principle.

Description

technical field [0001] The invention discloses a rapid densification method of a high-density full-gas-phase pyrolysis carbon-based carbon / carbon composite material, which belongs to the technical field of carbon / carbon composite material preparation. Background technique [0002] Carbon / carbon (C / C) composites, namely carbon fiber reinforced carbon matrix composites, is an advanced composite material integrating structure and function. It has high specific strength, high specific modulus, low density, excellent friction and wear properties, and good thermal shock resistance, ablation resistance, chemical stability and dimensional stability, etc. Since its birth, it has played an extremely important role in the fields of aviation, aerospace and weaponry. So far, C / C composite aerospace brake materials still occupy the largest market share of C / C composite materials. The preparation methods of C / C composites mainly include liquid phase impregnation and chemical vapor infilt...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/83C04B35/645
Inventor 汤中华熊翔张红波黄伯云
Owner CENT SOUTH UNIV
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