JPH01234367A - Production of carbon/carbon composite material - Google Patents

Abstract

PURPOSE:To obtain the title carbon/carbon composite material with a convenient method by carbonizing specified carbonaceous pitch, the precarbonized fiber made from carbonaceous pitch, and pitch-based carbon fiber under pressure. CONSTITUTION:(A) From 5 to 50 pts.wt. of carbonaceous pitch having 150-450 deg.C softening point, (B) 20-95 pts.wt. of >=1 kind between the infusibilized fiber obtained by infusibilizing the pitch fiber obtained by spinning carbonaceous pitch and the precarbonized fiber obtained by precarbonizing the above- mentioned infubilized fiber at 350-800 deg.C in an inert atmosphere, and (C) 5-80 pts.wt. of pitch-based carbon fiber are carbonized under pressing or under pressure to obtain the desired composite material. As the method for making the composite of the three components (A), (B) and (C), the components are mixedly crushed or separately crushed and then mixed, and the crushed mixture is carbonized under pressing or under pressure.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a method for manufacturing carbon/carbon composite materials.

Conventional problems and problems to be solved by the invention Carbon/
Carbon composite materials are materials that have unique properties such as maintaining high strength and high modulus of elasticity even at high temperatures of 1000°C or higher, and a low coefficient of thermal expansion, and are used as parts of aerospace equipment, brakes, furnace materials, etc. It is expected that it will be used for However, the manufacturing process for compositing the matrix and carbon fibers is complicated and takes a long time, resulting in high costs. An object of the present invention is to provide a method for producing a carbon/carbon composite material using a simple method.

Means for Solving the Problems The present inventors conducted research to develop a simple manufacturing process that solved the above-mentioned problems, and as a result, they completed the present invention.

The present invention relates to (A) 5 to 50 parts by weight of carbonaceous pitch having a softening point of 150 to 400°C, (B) infusible fibers obtained by infusible treatment of pitch fibers obtained by spinning carbonaceous pitch, and these infusible fibers. One or more types of m selected from the group consisting of pre-carbonized m fibers obtained by further pre-carbonizing the infusible fibers at 350 to 800°C in an inert atmosphere,
5t20 to 95 parts by weight, and (C) pitch-based carbon wi
Awei 5-80! The present invention relates to a method for producing a carbon/carbon composite material, which comprises carbonizing the deposited part under a press or under pressure.

The present invention will be explained in detail below.

In the present invention, (^) carbonaceous pitch has a softening point of 150
It is a coal-based or petroleum-based pitch having a temperature of -400°C, preferably 200-350°C. As the carbonaceous pitch, either optically isotropic pitch or anisotropic pitch can be used, but the content of the optically anisotropic phase is 60 to 100v.
o I%, preferably 80 to 100 vol. optically anisotropic pitch is particularly preferably used.

In the present invention, the pitch fiber (B) is a fiber having an average diameter of 5 to 100 μm, preferably 7 to 30 μm, obtained by melt-spinning the above-mentioned carbonaceous pitch by a known method. The infusible m-fiber referred to in the present invention refers to the pitch! It is a fiber obtained by infusible treatment of a male. The infusible treatment is
Under an oxidizing gas atmosphere, 50 to 400°C, preferably 10
It can be carried out at 0 to 350°C. As the oxidizing gas, air, oxygen, nitrogen oxides, sulfur oxides, halogens, or mixtures thereof can be used. The infusibility treatment is usually carried out for 10 minutes to 20 hours. On the other hand, the pre-carbonized fiber in the present invention refers to m-fiber obtained by further pre-carbonizing the infusible fiber. The pre-carbonization treatment is carried out under an inert gas atmosphere at 350 to 800°C, preferably 400 to 700°C, and is usually carried out for 10 minutes to 5 hours.

In the present invention, (C) pitch-based carbon fiber refers to a fiber obtained by further carbonizing or graphitizing the pre-carbonized fiber.

Carbonization treatment is performed at 700-2000℃ under an inert gas atmosphere.
It is usually carried out for 10 minutes to 5 hours. In addition, graphitization treatment is usually performed at 2000 to 3000°C for 1 second or more under an inert gas atmosphere.
It will be held for 5 hours.

In the present invention, (human) 5 to 50 parts by weight of carbonaceous pitch, preferably 10 to 40 parts by weight, CB) 20 to 20 parts of one or more types of fibers selected from the group consisting of infusible fibers and pre-carbonized fibers. 95 parts by weight, 25 to 50 parts by weight, and (C) 5 to 3,000 parts of pitch-based carbon fiber, preferably 10 to 7 parts by weight, are carbonized under a press or under pressure.

Carbonization under press is performed by hot pressing under an inert gas atmosphere at 5 to 500 kg/ct/, preferably 10 to 30 kg/ct/
0kg/cd, 400-2000℃, preferably 500
Perform at ~1500°C. Carbonization under pressure is performed by pressurizing with an inert gas to 50 to 10,000 kg/cd, preferably 100 to 3,000 kg/crl, and
It is carried out at 2000°C, preferably 500-1500°C. The fibers can also be preformed at room temperature prior to carbonization under press or pressure.

After carbonization under pressure or press, carbonization or graphitization may be carried out at 400 to 3000° C. under normal pressure and an inert gas atmosphere, if necessary.

Components (^) and (B) alone have insufficient reinforcing effect, and components (B) and (C) alone have insufficient moldability.
It is not possible to increase the aspect ratio of the reinforcing material component. Furthermore, if only the (human) and (B) components are used, the fluidity will be excessive during molding, and the binder component will flow out, leading to contamination of the carbonization equipment.

(^), (A method for compounding the three components Bl and (C) is, for example, by mixing and pulverizing these components, or by pulverizing them individually, mixing them, and carbonizing them under a press or pressure. Mixing and crushing should be done at least to the extent that the fibers retain their shape, and 1 m fibers of each
/d (aspect ratio) is 2 to 5000, preferably 5
~3000. Usually, 1/d of the infusible fiber or pre-carbonized fiber is smaller than 1/d of the pitch-based carbon fiber.

As another example, the two components (A) and (B) are mixed and ground, and this is mixed with pitch-based carbon, which is the component (C)! ! There is a method of filling the fibers into or between the fibers and carbonizing both under a press or under pressure.

man in the dust EXAMPLES The present invention will be specifically explained below with reference to Examples.

(Example 1) (Enter) Optically anisotropic phase with a softening point of 280°C 100v
o 1% petroleum pitch, (B) the above petroleum pitch was melt-spun to produce pitch fibers with an average diameter of 13 μm, and the pitch fibers were further infusible treated in air at 240°C; ) Three components of pitch-based carbon fiber with an aspect ratio of 300 were mixed into a 33-layer plate portion, 33 melon portion, and 3
Mix 3 parts by weight, crush, and hot press to 1
Press carbonization was performed at 1000° C. for 30 minutes under a pressure of 00 kg/c+/ to produce a carbon/carbon composite material with a bulk density of 1.6 g/cc. There was very little dirt in the hot press equipment, and the resulting material had a porosity of less than 10%. Observation using a polarizing microscope or an electron microscope revealed that the fiber structure was extremely uniformly distributed.

(Comparative Example 1) The infusible m-fiber of Example 1 was pulverized and the aspect ratio was 300.
IQO is made by hot pressing with pitch-based carbon fiber.
Press carbonization was performed at 1000° C. for 30 minutes under a pressure of kg/cf to produce a material with a scraping density of 1.6 g/ec.

The porosity of the obtained material was less than 10%, but the moldability was insufficient.

(Comparative Example 2) The pitch-based carbon m fibers of Example 1 were heated to 1
When press carbonized at 1000°C for 30 minutes under a pressure of 00 kg/c+/, the obtained product had poor moldability.
Machine processing was not possible.

(Comparative Example 3) When the pitch and pitch-based carbon fiber of Example 1 were press-carbonized by hot pressing at 1000° C. for 30 minutes under a pressure of 100 kg/at/, the pitch flowed out and could not be molded well.

The inside of the furnace was also contaminated.

(Example 2) (8) Optically anisotropic phase with a softening point of 280°C 100v
o1% petroleum pitch powder, (B) The petroleum pitch was melt-spun to form pitch fibers with an average diameter of 13 μm, which was infusible in air at 300°C for 1 hour, and then in nitrogen at 400°C. After processing for 1 hour, pre-carbonized fibers were obtained. 375 parts by weight of the pre-carbonized fiber tow was pulverized into fibers with an l/d of 10, and 375 parts by weight of the pulverized pitch product and (C) the l/d obtained by pulverizing the pitch-based carbon fibers were added to the fibers. Mix 25 parts by weight of fibers of 50% and make 100k by hot pressing.
Press carbonized for 1 hour at 600 °C under a pressure of g/c+/. This carbide was heated at 1200℃30 in a nitrogen atmosphere.
A separately fired carbon fiber-containing material with a bulk density of 1.6 g/cc was produced. The porosity of the obtained carbon material was less than 10%. Observation using a polarizing microscope or an electron microscope revealed that the m-fiber structure was extremely uniformly distributed.

(Example 3) Optically anisotropic phase with a softening point of 280°C 90vo I%
The petroleum-based pitch was melt-spun to obtain pitch fibers with an average diameter of 13 μm, which were then treated to be infusible in air at 300° C. for 1 hour to obtain infusible m-fibers. 25 parts by weight of this infusible fiber and 25 parts by weight of the pitch fiber were mixed and pulverized, and pitch-based carbon m
Filled between 50 layers of plain weave fiber, and hot pressed under a pressure of 50 kg/cd in a nitrogen atmosphere at 1200 kg/cm.
C. for 30 minutes to produce a carbon fiber-containing material with a bulk density of 1.7 g/cc. The porosity of the obtained carbon material is 10%
It was less than Observation using a polarized light mirror or an electron microscope revealed that the fiber structure was extremely uniformly distributed.

(Example 4) 100vo1% optically anisotropic phase with a softening point of 280°C
Pitch fibers having an average diameter of 13 μm obtained by melt-spinning petroleum-based pitch were treated to be infusible in air at 300° C. for 1 hour, and then treated in nitrogen at 350° C. for 1 hour to obtain pre-carbonized fibers. Before this, the carbonized fiber tow was crushed into fibers with a 1/d ratio of 10. ! 24 parts by weight of the pulverized pitch
After mixing 6 parts by weight and filling it between 60 parts by weight of plain weave pitch-based carbon fibers, it was placed in a stainless steel container and 2 parts by weight were mixed.
1000℃30 in a nitrogen atmosphere under a pressure of 00kg/ct
A carbon fiber-containing material having a partial pressure carbonization key density of 1.5 g/cc was produced. The porosity of the obtained carbon material was less than 5%. Polarization! Observation using a speculum or electron microscope revealed that the fibrous tissue matrix was extremely uniformly distributed.

Claims (1)

[Claims] (1) (A) 5 to 50 parts by weight of carbonaceous pitch having a softening point of 150 to 400°C, (B) Infusible fibers obtained by infusibility treatment of pitch fibers obtained by spinning carbonaceous pitch, and these The infusible fibers are further heated under an inert atmosphere.
One or more types of fibers selected from the group consisting of pre-carbonized fibers obtained by pre-carbonizing at 350 to 800°C 20
~95 parts by weight, and (C) 5 to 80 parts by weight of pitch-based carbon fiber
A method for producing a carbon/carbon composite material characterized by carbonizing a weight part under a press or under pressure.