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Preparation method of isotropic pyrolytic carbon

An isotropic, pyrolytic carbon technology, applied in the preparation/purification of carbon, etc., can solve the problems of limiting the density of isotropic carbon blocks, unfavorable application of isotropic carbon, etc., achieving small crystallite size and reducing preparation effect of temperature

Active Publication Date: 2013-09-11
无锡博智复合材料有限公司
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  • Abstract
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Problems solved by technology

This method solves the deficiencies in the traditional preparation method of isotropic pyrolytic carbon to a certain extent. However, due to the high crystallinity of carbon nanotubes, the Lc of the prepared isotropic pyrolytic carbon (carbon material ( 002) surface stacking height) is large, which is not conducive to the application of isotropic carbon in the field of neutron radiation prevention
On the other hand, the hollow structure of carbon nanotubes restricts the deposition of pyrolytic carbon inside them, which limits the density of isotropic carbon blocks to some extent.

Method used

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  • Preparation method of isotropic pyrolytic carbon
  • Preparation method of isotropic pyrolytic carbon
  • Preparation method of isotropic pyrolytic carbon

Examples

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Effect test

example 1

[0025] (1) Using amorphous carbon nanofibers as raw materials, wet the carbon nanofibers with alcohol. When wetting, the volume ratio of alcohol and amorphous carbon nanotube fibers is 1:1.

[0026] (2) Press the wetted carbon nanofibers into a rectangular graphite die (groove size is 40×5×2), the pressure is 15MPa, and the holding time is 5min. After that, it was placed in a backlit environment at room temperature to dry to obtain a carbon nanofiber preform with a volume fraction of 30%.

[0027] (3) Put the graphite die containing amorphous carbon nanofibers into a fixed-bed CVD reactor, and raise the temperature to 950°C under the protection of nitrogen (nitrogen flow: 100L / h).

[0028] (4) After the temperature rises to the set value, turn off the nitrogen, and at the same time feed the mixed gas of propylene / hydrogen. The flow rates of propylene and hydrogen are 30L / h and 150L / h respectively. The reaction time is 3 hours, the power is turned off to cool down, the coolin...

example 2

[0031] (1) Using amorphous carbon nanofibers as raw materials, wet the carbon nanofibers with alcohol. When wetting, the volume ratio of alcohol and amorphous carbon nanotube fibers is 1:1.

[0032] (2) Press the wetted carbon nanofibers into a rectangular graphite die (groove size is 40×5×2), the pressure is 20MPa, and the holding time is 5min. After that, it was placed in a backlit environment at room temperature to dry to obtain a carbon nanofiber preform with a volume fraction of 40%.

[0033] (3) Put the graphite concave mold containing amorphous carbon nanofibers into a fixed bed CVD reaction furnace, and raise the temperature to 930°C under the protection of nitrogen (nitrogen flow rate: 100L / h).

[0034] (4) After the temperature rises to the set value, turn off the nitrogen, and at the same time pass in the mixed gas of propylene / hydrogen, the flow rates of propylene and hydrogen are 40L / h and 140L / h respectively. The reaction time is 3 hours, the power is turned of...

example 3

[0037] (1) Using amorphous carbon nanofibers as raw materials, wet the carbon nanofibers with alcohol. When wetting, the volume ratio of alcohol and amorphous carbon nanotube fibers is 2:1.

[0038] (2) Press the wetted carbon nanofibers into a rectangular graphite die (groove size is 40×5×2), the pressure is 30MPa, and the holding time is 5min. After that, it was placed in a backlit environment at room temperature to dry to obtain a carbon nanofiber preform with a volume fraction of 45%.

[0039] (3) Put the graphite concave mold containing amorphous carbon nanofibers into the fixed bed CVD reaction furnace, and raise the temperature to 900°C under the protection of nitrogen (nitrogen flow: 100L / h).

[0040] (4) After the temperature rises to the set value, turn off the nitrogen, and at the same time feed the mixed gas of propylene / hydrogen. The flow rates of propylene and hydrogen are 50L / h and 130L / h respectively. The reaction time is 3 hours, the power is turned off to c...

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Abstract

The invention relates to a preparation method of isotropic pyrolytic carbon. According to the method, propylene is used as a carbon source and amorphous carbon nanofiber (one-dimensional solid carbon nano-material) preform is densified by virtue of fixed bed CVD (chemical vapor deposition) to prepare isotropic pyrolytic carbon. The method is low in preparation temperature (1000 DEG C) and broad in process conditions; prepared isotropic pyrolytic carbon has small crystallite size; the operation is simple. The preparation method disclosed by the invention has the beneficial effects that: (1) the preparation temperature of the isotropic pyrolytic carbon is further decreased; (2) the crystallite size of a prepared isotropic pyrolytic carbon is small; and (3) compared with reported methods, the method disclosed by the invention can be used for preparing isotropic pyrolytic carbon with higher apparent density within a same time.

Description

technical field [0001] The invention relates to a method for preparing isotropic pyrolytic carbon, in particular to a method for preparing isotropic pyrolytic carbon by densifying an amorphous carbon nanofiber preform by means of a low-temperature fixed-bed chemical vapor deposition technique. Background technique [0002] Isotropic pyrocarbon, as a high-temperature pyrolysis product of hydrocarbon gases (such as methane, propane, propylene, etc.), is composed of randomly oriented graphene crystallite structure and indeterminate carbon in between (Texture characterization and mechanical properties of pyrocarbon obtained by chemical vapor deposition at 1450–1550°C. Materials Science and Engineering A. 2012). Compared with layered pyrolytic carbon, isotropic carbon has no texture characteristics in structure, so it is also called turbostratic pyrolytic carbon. Isotropic carbon has small grain size, compact structure, and uniform performance. In addition to the advantages of g...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/02C01B32/05
Inventor 李克智宋强李贺军
Owner 无锡博智复合材料有限公司
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