JPS61146775A - Carbon 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] (Industrial application field) The present invention relates to carbon fiber reinforced carbon materials.

(Prior Art) Carbon fiber-reinforced carbon materials (hereinafter referred to as C/C composites) are lightweight and have high strength (high specific strength), so their use in advanced technology fields is expected to increase. However, since conventional C/C composites are composed only of carbon materials, they are oxidized and consumed in high-temperature oxidizing atmospheres of 400° C. or higher, which limits the field of use. For example, due to its high specific strength, it is used as a disc rotor, which is part of the brake mechanism of aircraft, but the peripheral area of the disc rotor is oxidized and worn away due to frictional heat, so metal is used to prevent oxidation. I have no choice but to use it with a ring attached.

(Objective of the Invention) The present invention improves the above-mentioned drawbacks and provides carbon fibers with improved oxidation resistance.
/C composite.

(Structure of the Invention) The present invention relates to a C/C composite in which a layer of an oxidation-resistant substance is formed on the surface of a base material and on the surface of pores inside the base material.

In the present invention, the base material of the C/C composite is preferably one obtained by kneading short fibers of carbon fibers (including graphite fibers) and a thermosetting resin such as 7-enol resin FES, then molding and firing.

Oxidation-resistant substances include * Siv TJ * It W,
Ta.

Carbides of elements such as carbon dioxide are preferred because they have excellent oxidative wear resistance.

In order to form a layer of an oxidation-resistant substance on the surface of the base material and on the surface of the pores inside the base material, first 8L'ri, B, W.

TI or) l alcolade e.g. 8i (QCCnH2
After impregnating the C/C composite substrate with the solution of 4.

Hydrolyze with hydrochloric acid, etc. The oxide of the element is attached to the surface of the base material and to the surface of the pores inside the base material by impregnating the base material with a sol of the oxide of the element. Next, after drying and volatilizing the solvent, the base material containing the oxide is placed in a container made of heat-resistant material such as graphite and heat-treated in a non-oxidizing atmosphere to cause the oxide to react with the carbon of the base material to form a surface. By means such as forming a carbide film on the After forming an oxidation-resistant substance, the 7'LC/C composite is washed with hydrofluoric acid and an aqueous solution of caustic soda to remove glass particles and the like.

(Example) Next, an example will be described.

Example 1 40 parts by weight of short carbon fibers (manufactured by Toho Peslon, trade name Pesphite) and 100 parts by weight of phenolic resin face (PR524, manufactured by Hitachi Chemical) were kneaded in a pressure kneader, and the pulverized molding powder was heated at 160°C. 300kg/am at a temperature of
The molded body was molded under a pressure of 8 minutes for 8 minutes to form a molded body with a thickness of 10 cm, which was then fired from room temperature to 1000°C for 96 hours to obtain a density of 1.5 degrees, a bending strength of 10 kg/m, and a porosity of 10.
A base material of 96 C/C composite was obtained. This base material was placed in an autoclave and the pressure was reduced to +3 mmHg or less, and then 60 parts by weight of a solution of 5i (OCsHs)4 (Ethyl Silicate 40, manufactured by Nippon Colcoat) and 32 parts by weight of ethyl alcohol were added.
parts by weight, 8 parts by weight of 5% hydrochloric acid, 1 part by weight of NaC powder (SiC
5 parts by weight of a homogeneous mixture (added to improve the yield of chemical reaction) was injected and impregnated, returned to normal pressure, taken out, air-dried, and dried at 150°C for 5 hours to remove KSiCh and N on the surface and in the pores of the substrate.
Remove alcohol and water, leaving aCl behind. Next, this base material was filled into a graphite pod evenly spread with NaCl, and this pod was placed in a graphite reaction vessel, heated in an argon gas atmosphere, and held at 1500°C for 3 hours to form a silicon pod.
Converted to C. Thereafter, the C/C composite base material was taken out from the reaction vessel and washed with hydrofluoric acid and then a caustic soda aqueous solution to remove Si-based glassy components on the surface.

Example 2 Same as Example 1, density 1.62 bending strength 10 kg/
A C/C composite base material with a porosity of 12% and a porosity of 12% was obtained. This base material was immersed in a 3% by weight NaCl aqueous solution.
Dry at 100℃ and then put in an autoclave to 3mmH.
The pressure was reduced to below 1.5 g, and after injecting and impregnating 5 inches of sol (manufactured by Nissan Chemical, trade name: Snowtex 0), the pressure was returned to normal pressure, taken out, and dried at 150° C. for 5 hours.

Next, this base material was placed in an electric furnace, and the surrounding area was covered with a packing powder made of silica powder and graphite powder, and the temperature was raised by passing an electric current through it, and heat treatment was performed at 2000° C. for 2 hours to form SiC.

After repeating the steps of impregnating Snowtex and converting it into SiC four times, it was washed with hydrofluoric acid and an aqueous solution of caustic soda.

A C/C composite base material without impregnation heat treatment is used as a comparative example, and 25a from the C/C composite of the example and comparative example.
A test piece of m square x 5 m thickness was made and heated at (a) 800°C for 2 hours, (Blo00°C; 2 hours and Ic) 1500°C.
An oxidative depletion test was conducted under conditions of , 2 hours. The results are shown in Table 1.

As is clear from Table 1, the C/C composite of the comparative example was oxidized! Although it disappears at temperatures above 11,000°C, the weight loss due to oxidative consumption is reduced in the examples.

(Effect of the invention)

Claims (1)

[Claims] 1. A carbon fiber-reinforced carbon material in which a layer of an oxidation-resistant substance is formed on the surface of a base material and on the surface of pores inside the base material. 2. The oxidation-resistant material is SiC, TiC, B_4C, WC,
The carbon fiber reinforced carbon material according to claim 1, which is TaC or Al_3C_4.