JPH01257172A - Method for joining carbon fiber/carbonaceous material composite material - Google Patents

Abstract

PURPOSE:To reduce the weight of a joined part and to improve the durability by applying a graphite adhesive to the joining parts of composite materials each made of a carbon fiber reinforced carbonaceous material, winding a carbon fiber and carrying out heat treatment. CONSTITUTION:The graphite adhesive is applied to the joining parts 2 of composite materials 1, 1' each made of a carbon fiber reinforced carbonaceous material and the parts 2 are stuck to each other. The carbon fiber 3 is wound around the stuck part while applying the adhesive to fix the parts 2. Heat treatment is then carried out at a prescribed temp. to cure the adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for joining carbon fiber/carbonaceous composite material (hereinafter abbreviated as C/C composite).

[Prior Art] Today, composite materials consisting essentially of carbonaceous material reinforced with carbon fibers, i.e. C/C composites, for example about 140
It is seen as a promising heat-resistant material that can be used at high temperatures of 0°C or higher. However, if you try to manufacture large or long items using the C/C composite, you will need large processing equipment and high processing costs. Conventionally, this has been dealt with mainly by joining small returned objects to make long objects.

That is, as shown in Fig. 3, the C/C composite 1°1°
To join, bolt 4. Natsu 5. washer 6,
They are joined using joining members such as the backing plate 7, and these joining members are made of metal materials with high melting points, such as molybdenum (melting point: 2,625 ± 50°C), tungsten (melting point: 2,996 ± 50°C), etc. It's here.

[Problems to be Solved by the Invention] However, such conventional bonding means for C/C composites may be damaged due to, for example, seizure of screws or embrittlement in an inert gas atmosphere such as nitrogen gas, or damage to the bonding matrix. Due to the difference in thermal expansion between the Furthermore, the above-mentioned bonding materials tend to creep when used for long periods of time under high temperatures, and since they have a higher specific gravity than C/C composites, handling properties are reduced due to the increased weight of the bonded parts, and the bonding materials are expensive, making it difficult to bond them. It also had drawbacks such as high cost.

The problem to be solved by the present invention is to eliminate the drawbacks of the above-mentioned conventional techniques regarding joining of C/C composites, and to provide a joining method in which the joining part is lightweight and durable, and at the same time can be implemented easily and at low cost. .

[Means for Solving the Problems] The above-mentioned problem to be solved by the present invention is to bond carbon fiber-reinforced composite materials substantially made of carbonaceous materials to each other by applying carbon fibers to the bonded portions via a graphite adhesive. This can be achieved by applying heat treatment after winding.

Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a schematic view showing an example of C/C composite bonding according to the present invention, and FIG. 2 is a sectional view taken along line A-^ in FIG. In the figure, 1,1゛ is C/C composite, 2 is the joint surface,
3 is carbon fiber.

As shown in the figure, when joining the C/C composites 1, 1', first, a graphite adhesive (not shown) is applied to the joint portion (particularly the joint surface) 2, and the two are bonded together. Graphite adhesive is then applied on top of this and carbon fiber is wrapped around it to secure the joint. In other words, at the same time that the carbon fiber is wrapped around the joint with sufficient strength,
The graphite adhesive bonds the C/C composites to each other and the C/C composites to the carbon fibers.

Note that if a knock pin made of the same material is driven into the C/C composite 1.1 degree joint as necessary, the durability of the joint can be roughly extended.

Next, the bonded portion after adhesive fixation requires heat treatment of curing and firing to harden the graphite adhesive. Since the purpose of this curing is to dry the graphite adhesive, the heat treatment temperature and heat treatment time can be set appropriately depending on the material of the adhesive. Heat treatment time is approximately 3
~4 hours is a preferred range.

After curing the joint, C/C in an inert atmosphere such as N2, Ar, He, etc. or a reducing atmosphere such as H2.
The temperature is gradually raised to the working temperature of the composite (approximately 1400'C or higher), and firing is performed for approximately 0.5 hours. Through these curing and firing processes, the C/C composite joint becomes lightweight and has excellent durability.

Carbon I at this time! As the fibers, conventionally known carbon fiber strands or carbon fiber cords are used, and the strands or cords may be twisted or non-twisted.

Further, the graphite adhesive may be a known adhesive, and for example, Newcoat GC (manufactured by Dainippon Ink), VA58 (manufactured by Jiggly), etc. are preferably used.

[Example] Hereinafter, the present invention will be specifically explained with reference to Examples.

Example C/(, l composite (20mm square x 2,000mm
) are cut by 300 mm in the length direction and 10 mm in the thickness direction. Apply graphite adhesive (Ucoat GC) to the cut surfaces and stick them together.

Afterwards, apply graphite adhesive to the surface of the joint and strand approximately 10 m of carbon fiber (approximately 12,000 denier).
Wrap around. After being left to stand for about 2 hours, it was heat-treated in an atmosphere of 130° C. for 4 hours.

The material was gradually fired to about 3,000° C. in a rough N2 atmosphere.

A cleaning jig and an operating jig for a high-temperature firing furnace (approximately 1400° C. or higher) were manufactured using the C/C composite bonded in this manner.

The obtained jig is lightweight and has good handling properties.
With conventional bonding methods, products that could only be used for about one month due to durability and heat resistance were able to be used for one year without any problems.

[Effects of the Invention] According to the C/C composite bonding method of the present invention, ■The heat resistance and durability of the bonded portion at high temperatures, particularly at temperatures above 1400°C and below 3300°C, are significantly improved; C/C composite products can be used stably for a long period of time.

■Since the bonding material is a carbonaceous material that is the same as the bonding base, weight increase is kept to a minimum and there is almost no deterioration in handling properties.

■Since the joining method is easy and the material cost is minimal, joining costs can be reduced significantly.

As such, Qin has a remarkable effect.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an example of C/C composite joining according to the present invention, Fig. 2 is a sectional view taken along line A-A of the joining example of Fig. 1, and Fig. 3 shows an example of conventional C/C composite joining. It is a schematic diagram. 1.1'': C/C composite 2; joint surface 3; carbon fiber 4; bolt 5; nut 6; washer 7; backing plate

Claims (1)

[Claims] When bonding composite materials made essentially of carbonaceous materials reinforced with carbon fibers, carbon fibers are wound around the bonded portion via a graphite adhesive and then heat treated. A method for joining fiber/carbonaceous composite materials.