JPS6236075A - Fiber reinforced carbon material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the improvement of fiber-reinforced carbon materials in which carbon powder is mixed with inorganic fibers or metal fibers.

[Conventional technology]

Among various carbon materials, high-strength carbon materials are particularly used for various electrodes, nuclear graphite materials, and Ruthenium carbon materials. It is used in a wide range of fields, including heaters, mechanical sealing materials, sliding current collectors, and hot press dies. As high-strength carbon materials suitable for such uses, carbon materials reinforced with carbon fibers are said to have excellent performance.

In the production of carbon materials reinforced with carbon fibers, carbon fiber woven fabrics are generally hardened with thermosetting polymers such as phenolic resin, and after hardening, carbonization or graphitization treatment is performed. The pores generated during the graphitization process are impregnated with resin again, and the impregnation process is performed to carbonize and graphitize.
A method of repeating ~5 times is adopted.

This method requires a high blending rate of expensive carbon fibers and requires a number of steps, so the carbon material obtained is extremely expensive, and therefore it is used only in limited fields such as aircraft and space industries. It was unsuitable for general industrial use.

Therefore, methods for producing carbon fiber-reinforced carbon materials without impregnation treatment have been proposed.

For example, as seen in Japanese Patent Publication No. 49-29281, there is a method in which specific organic fibers are added to an inorganic or carbon aggregate and an organic binder and fired. Furthermore, as shown in Japanese Patent Application Laid-Open No. 51-87515, there is a method in which carbon fibers are wetted with a liquid organic binder, the carbon fibers are mixed with carbon powder and an organic binder, and then molded and fired.

[Problems with conventional technology]

None of the above methods require impregnation treatment, and the fibers to be mixed are carefully selected. However, in the process of adding the fibers, carbon powder, and organic binder to kneading, molding, and firing, It is necessary to mix and knead the carbon powder so that it is sufficiently wetted, and the fibers are pulverized by kneading.

■ During kneading and pressure molding, coarse carbon particles or aggregates damage fibers and turn them into powder.

■ During the firing process, microcracks occur frequently due to the difference in shrinkage rates of the three raw materials: fibers, carbon particles, and organic binder.

Due to these adverse conditions, the bending strength was 800 kg/cm.
There was a problem that a carbon material with a high strength of 2 or more could not be obtained, and a carbon material with excellent wear resistance could not be obtained.

The present invention solves the problems of conventional methods by strengthening the bonding strength between fibers and carbon powder, and also achieves high strength and wear resistance that does not require impregnation treatment and can be manufactured using an economical manufacturing method. Our objective is to provide excellent fiber-reinforced carbon materials.

[Technical means for solving the problem] The fiber-reinforced carbon material of the present invention is selected from inorganic fibers and metal fibers.
1 or 2 or more fiber materials 3-60% by weight and carbon powder 30%
It is characterized in that it is made by adding 1 to 10% by weight of an oxide sintering aid such as yttrium oxide to a composite material mixed with 1 to 96% by weight.

Here, carbon powder refers to carbon powder obtained by kneading coke or graphite with a binder such as coal tar pitch or phenol resin, or by polycondensing pitch to give it self-sintering properties.

Inorganic fibers to be mixed with this carbon powder include carbon fibers, glass fibers, silicon carbide fibers, and the like. Furthermore, examples of metal fibers include steel fibers and copper fibers. These fiber materials have a length of 200m+n or less, and L (length)/
It is preferable that D (thickness)≧50 and strength is 50 ky/mn2 or more.

Among the oxide sintering aids, yttrium oxide is particularly effective in improving the strength and wear resistance of fiber-reinforced carbon materials.The particle size is not particularly limited, but may be 10 μmφ to 200 μm.
φ is good.

In the present invention, the reason why the fiber material is limited to 3 to 60% by weight is that if the fiber material exceeds 60%, the binder component (the binder contained in the carbon powder and the volatile content equivalent to the binder) that is attached to the fibers This is due to the fact that the adhesion strength is not ensured due to a decrease in the ratio of 10% by weight, and that if the amount is less than 3% by weight, the complementary effect of the fiber material cannot be obtained.

The reason why the yttrium compound is 1 to 10 times i-
Even if it is added in excess of 10% by weight, it will only increase the cost and will not be very effective, and if it is added as low as 1% by weight,
This is because the bonding force between the fiber material and the carbon powder decreases.

The above-mentioned fiber-reinforced carbon material is obtained by adding and mixing a yttrium compound to a composite material of a fiber material and carbon powder, molding and firing the composite material according to a conventional manufacturing method.

[For production]

Adding an oxide sintering aid such as yttrium oxide to the composite material
By adding 10% by weight, the voids between carbon particles and fibers are filled and the bonding strength is improved, so that a fiber-reinforced carbon material with excellent strength and wear resistance can be obtained.

〔Example〕

Raw materials consisting of 5% to 8% by weight of carbon fiber, 87% to 90% by weight of self-sintered carbon powder, and 5% by weight of yttrium oxide were mixed and ground in a grinder for 40 minutes, and the mixed material was crushed using a press. Molding was performed at 2 T/cnt2. The molded product is carbonized and fired at 1800~24℃.
Graphitized at 00°C.

Physical properties such as bending strength in this example are shown in Table 1 together with the conventional example.

The fiber reinforced carbon material of the present invention has a bending strength of 960 to 12
50kgf/crn2, impact strength 3.6-7.0k
Flf·crrv'cm2, which is superior to conventional graphite and metal-impregnated carbon materials.

In addition, the specific wear amount of the fiber-reinforced carbon material of the present invention is determined from pure car? Comparisons were made between carbon materials containing carbon and other sintering aids. The results are shown in FIG.

For comparison, the examples are examples in which 1.3 and 5.8% by weight of yttrium oxide were added to the composite material, and the comparative examples were carbon in which 5% by weight of yttrium oxide + 2% by weight of aluminum oxide were added to the composite material. These are three comparative examples of materials, a carbon material in which 15% by weight of boron carbide and 10% by weight of silicon carbide are added to a composite material, and pure carganese in addition. In both cases, the manufacturing process was the same, and graphitization was performed at a firing temperature of 2,200°C.

The specific wear amount in the example is 10 trrm3/haze when 1% by weight of yttrium oxide is added to the composite material.
kgf, the amount of IJium oxide decreases as the amount increases, and at 8% by weight 6 X 10 m+3/rtv
It is 9f on n-. It can be seen that compared to cases where pure carbon or other sintering aids are added, the case of the present invention in which the IJ compound is added is also superior in terms of specific wear amount. Taking advantage of these excellent points and the low electrical resistivity, the fiber-reinforced carbon material according to the present invention can be used for sliding current collectors such as trolley wires, which have particularly severe usage conditions.

〔Effect of the invention〕

According to the present invention, by adding 1 to 10% by weight of an oxide sintering aid such as ino-IJium oxide to the composite material,
A fiber-reinforced carbon material with excellent strength and wear resistance can be obtained.

Furthermore, since the fiber-reinforced carbon material of the present invention can be obtained by molding and firing without impregnation treatment, it is inexpensive and can be used in general industry.

[Brief explanation of the drawing]

FIG. 1 is a graph comparing the specific wear amount between the present invention and a comparative example.

Claims (1)

[Claims] (1) 1 or 2 selected from inorganic fibers and metal fibers
Fiber-reinforced carbon characterized by adding 1 to 10% by weight of an oxide sintering aid such as yttrium oxide to a composite material obtained by mixing 3 to 60% by weight of the above fiber material and 30 to 96% by weight of carbon powder. material.