JPS62108768A - Manufacture of whisker-containing carbon composite 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] Industrial Field of Application The present invention relates to a method for strengthening glassy carbon, and more specifically, to a method for strengthening glassy carbon, which produces a glassy carbon material in which whiskers are uniformly dispersed, without cracking, and which is conventionally obtained. The present invention relates to a method for producing a high-strength carbon material with a thickness of 100%.

Conventional technology and its problems Conventionally, in order to increase the mechanical strength of an element, carbon LfJ
When adding a binder to the base material and filling it, the
Methods of adding reinforcing materials such as awls or whiskers are known. However, it is difficult to uniformly disperse the wa fibrous reinforcing material in the matrix, for example,
In No. 194777, a pressure of α1 kg/cin" or more is applied during combination, but the amount of 1 that can uniformly add whiskers is only about 5%, and the degree of improvement in bending strength etc. is small.

Means to Solve the Problems In the present invention, since the above-mentioned carbonaceous filler cannot sufficiently increase the strength of the strut, 2. A carbon material consisting of an invasive filler and a binder is avoided as a substrate; We use a phenolic resin powder that produces glassy carbon when fired, and in order to further increase its strength, we mix the resin powder and whiskers using a wet method to obtain a glassy carbon material with evenly dispersed voice cars. I came up with the idea of doing this, and after repeated research, I was able to complete the present invention.

The method for producing a whisker-containing composite material according to the present invention involves dispersing resin powder that produces glassy carbon and whiskers in a dispersion a to form a slurry, and adding a dispersion medium from the slurry 〇). removing by a conventional method to produce a whisker-containing layered powder body, further press-molding the powder body,
It is characterized by being fired.

By the above method, while maintaining the non-porosity of glassy carbon a, the whisker addition electric potential is ensured to be 10% or more, the bending strength etc. are increased, and a thick carbon with no cracks, which has not been obtained conventionally, can be obtained. product is obtained.

The 8M fat powder used in the present invention may be one that becomes glassy carbon after pressure molding and firing, and phenolic resin (thermosetting resin obtained by condensing phenols and aldehydes with acid or alkali). (referring to synthetic resin),
Examples include phenol formaldehyde, and any thermosetting resin with a large coking value (residual carbon) such as furan resin may be used.

The particle size of the above-mentioned layered powder may be as long as it can be mixed with whiskers during mixing by a wet method, for example, 10 to 500 μm.
A range of approximately m is sufficient.

On the other hand, whiskers have a diameter of about 01 to 10 μm,
It is preferable to use one with an aspect ratio of about 10 to 500, because if the aspect ratio is 500 or more, it will be difficult to disperse, but if the aspect ratio is within this range, a larger aspect ratio is preferable for increasing the bending strength. Whiskers are added in an amount of 15 to 40% by weight based on the powder. If it is less than 15%, cracks may occur during firing of the molded product, and if it is more than 40%, the denting strength will be greatly reduced, which is contrary to the purpose of the present invention.

Examples of whisker types include β-type silicon carbide (S
in), aluminum nitride (AIN), boron nitride (B
N), silicon nitride (Si3N4), graphite (C), boron carbide (B4C), etc. can be used.

Any dispersion medium may be used as long as it can disperse the sugar beet powder and whiskers by a wet method, such as water.

Alcohols (ethyl alcohol, methyl alcohol, etc.) and mixtures thereof can be used, and if necessary, an anionic surfactant known as a dispersant.

Add a nonionic surfactant or coupling agent (wetting agent between resin and whiskers). The slurry concentration has no particular effect on uniform dispersion, but it is between 100 and 30.
0 g solid content/l (solid content = sum of whisker weights on 82f fat powder) is preferable from the operational point of view.

The system of the resin powder, whiskers, and dispersion medium is stirred by a conventional method such as rotary stirring to a degree that does not cut the whiskers too much to loosen and disperse the whiskers. Thereafter, it may be filtered and dried by a conventional method, or only drying may be used as long as the dispersion of the whiskers and N1m powder does not become compartmentalized. In this way, a powder body in which whiskers are uniformly dispersed in the NfN powder is obtained. Whiskers alone have poor fluidity, but a mixture of fi2 and fat powder has flu
J-ness improves.

Next, the dried product is pressure-molded by a conventional method, for example,
Shape it into the specified shape by hot pressing.

In hot press, the molding pressure is 10 to 100 kg/c.
The heating is carried out slowly within a range of m2 temperature of 130 to 250°C and pressurization time of about 10 to 60 minutes. At that time, the powder is degassed by the molding pressure, and then thermally cured through a highly viscous melt. After curing, the molded article is released from the mold, which has been previously treated with a mold release agent.

Furthermore, the resin powder is converted into glassy carbon by firing the molded product to obtain a glassy carbon product in which whiskers are uniformly dispersed. The firing conditions should be as slow as possible and the heating rate (10
The firing temperature is preferably 950 to 1200°C since it is difficult to graphitize the charcoal, although it may be graphitized depending on the case.

Operation According to the invention, the whiskers are dispersed in an old-fashioned manner, so that
It is uniformly dispersed in the glassy carbon, and unlike the case of I1, no strong shearing force is applied during mixing, so there is almost no breakage of the whiskers and the characteristics of the whiskers are maintained. In addition, by 7-filtration, dry Q, and pressure molding, it is possible to obtain a high-strength composite material with uniformly dispersed whiskers, and the effect of adding whiskers can counteract the heat shrinkage during firing, so there is no cracking. A relatively thick product can be obtained.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to examples and comparative examples.

Actual example, comparative example As phenol layer powder, true specific gravity 1.25g/Cm3
．． Bulk density α3g/crn3. y, V! of heat-melting and curing type with a diameter of 1-20 μm. ! A slurry with a concentration of 20% was prepared by using oil (manufactured by Kanebo Co., Ltd., trade name: Belbar S-970) and β-type SiC whiskers with a diameter α of 5 to 1 μm and an aspect ratio of 100 to 200, using water as a dispersion medium. was prepared. Stir this slurry at a stirring concentration (approximately 50 or
pm), water was removed by suction and filtration, and vacuum drying was performed to remove adhering moisture.

The dried product was molded using a hot press. In the hot press, a 0.2 mm thick polyester film coated with silicone is placed on two aluminum plates (90 w x 90 x 10 hmm) equipped with a 100 W heater on the back, and the dried material is poured onto the film at a predetermined rate (f1 input). Press temperature 150°C, press pressure 50 kg 7cm2.
It was molded for 20 minutes, cooled, and then released from the mold.

The molded product is sandwiched between two carbon plates and weighs approximately 15g/
5cm from room temperature in please coke with a load of 5cm2.
5°c/hr to 00°C, 500°C to 1000°C
The temperature was raised at a rate of 10°C/hr until it reached 1000°C.
After cooling, the physical properties of the fired product were determined to be 1llI.
added.

Table 1 below shows the amount of whiskers added to the layer.

The results of experiments with various thicknesses of molded products during molding are shown.

As a comparative example, a case containing phenol MB fat without whiskers was subjected to hot pressing and baking in the same manner as in the examples, and its physical properties were investigated. The results are also listed in Table 1.

As shown in Table 1 below, the indentation strength of the material with 30% whiskers added is two folds higher than that of the material without the addition of whiskers. As can be seen from the examples, the bending strength peaks at about 30% of the amount of whiskers added, and decreases thereafter.

In addition, for the phenol sweet nHL flavor, the thickness when molded is 2 mm.
However, according to the present invention, no cracks occur even when the thickness at the time of molding is 8 mm.

Effects of the Invention With the present invention, a product with high strength can be obtained, which has a bending strength of about 1300 kg/cm (!), whereas conventional products made by the covering method of carbonaceous filler and whiskers had a tearing strength of about several hundred kg/cm2. .

Furthermore, conventionally, glass-like bulk products obtained by firing resin powder have a thickness of 1 mm without cracking.
However, according to the method of the present invention, it is possible to obtain crack-free products with a thickness of about 1Q mm during molding, further expanding the range of use of high-strength carbon materials. It is something to do.

Claims (1)

[Claims] 1. Dispersing resin powder that produces glassy carbon and whiskers in a dispersion medium to form a slurry, removing the dispersion medium from the slurry by a conventional method to produce a whisker-containing resin powder, and further comprising: Pressure molded,
A method for producing a whisker-containing carbon composite comprising firing.