JPS62270463A - Manufacture of carbon fiber reinforced 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 3. Detailed Description of the Invention <Industry> 2. Field of Application This invention relates to a method for manufacturing a carbon fiber reinforced carbon composite material having high performance.

<Conventional technology and its problems> Carbon IIi fiber-reinforced carbon composite material (hereinafter referred to as CFRC)
Films are mainly manufactured by vapor phase chemical vapor deposition method and liquid phase impregnation method.

The CVD method is a method in which hydrocarbon gas is brought into contact with a carbon fiber base material heated to a high temperature under reduced pressure to deposit carbon atoms on the base material, and the liquid phase impregnation method is a method in which a carbon fiber base material is heated to a high temperature and is brought into contact with hydrocarbon gas to deposit carbon atoms on the base material. It is impregnated with a 71-lix material such as pitch and then carbonized and fired. At this time, the volatile components of the matrix material escape, creating fine pores, so it is necessary to repeat the impregnation and firing process in order to increase the strength of the material.

Both the CVD method and the impregnation method require complicated and long-term processes, which is one of the reasons for the high price of CFRC. For this reason, although CFRC has excellent material properties such as high-temperature strength and chemical stability, its current practical use is limited to fields such as the aerospace industry, where there are few economic constraints.

On the other hand, recently, in the case of ordinary carbon materials that are not reinforced with fibers, it has become possible to easily manufacture carbon materials by directly carbonizing and firing fine carbon powder without using a liquid matrix material.

Since this method uses a matrix material that has already been heat-treated, it has the advantage that a high-density carbon material can be obtained in a short firing time because the volatile content of the matrix is small. Everyone expects that by mixing this fine carbon powder into a carbon 4I fiber base material and firing it, a simple CFRC can be produced immediately, but in reality, carbon 1i
It is very difficult to uniformly mix carbon powder into the 1i1Mt base material, making it impossible to make good CFRC.

From this point of view, the present inventors have previously developed a method for producing carbon composite materials using electrophoretic deposition (electrodeposition) (Japanese Patent Laid-Open No. 60-54974), and a thermosetting material as a carrier in this method. He proposed the use of resin (Japanese Patent Application Laid-Open No. 61-21973). However, these above methods
Step 1: Precipitate carbonaceous powder and carrier on mN base material.
I only did it once.

In this conventional method, carbon 41! It takes time to uniformly precipitate a large amount of carbonaceous powder and carrier on LiF, and there is a limit to the amount and uniformity of precipitation, so it is impossible to achieve both.

This is because in order to precipitate a large amount of carbonaceous powder and carrier, it is necessary to reduce the amount of carrier relative to carbonaceous powder, and in order to deposit uniformly, it is necessary to increase the amount of carrier relative to carbonaceous powder. This is because it is difficult to find a compounding system that achieves both durability and uniformity in one electrodeposition.

<Means for Solving the Problems> In order to overcome the drawbacks of the above-mentioned conventional method for producing carbon 111i fiber-reinforced carbon composite materials, the present inventors have incorporated carbonaceous powder and a carrier into a carbon fiber base material. This invention was developed as a result of studies on how to deposit a large amount and uniformly on the surface.

That is, in this invention, a carrier that can be ionized in a liquid is adsorbed onto a carbonaceous fine powder, and then dispersed in the liquid, and then a carbon fiber base material and a counter electrode are immersed in the dispersion liquid. Carbonaceous powder and carrier are deposited on the carbon 41i fiber base material by applying a direct current voltage between the base material and the counter electrode to obtain a coating, and this coating is dried, thermoformed, heat treated, and carbonized. In the manufacturing method of fiber reinforced carbon composite material,
When depositing the coating, first deposit a carbonaceous powder with a comparatively large weight ratio of carrier to carbonaceous powder, and from the second time onwards deposit a powder in which the weight ratio of carrier to carbonaceous powder is smaller than that of the previous deposit. The present invention provides a method for producing a carbon fiber-reinforced carbon composite material characterized by precipitation.

<Function> In short, this invention first precipitates a carbonaceous powder with a relatively large weight ratio of carrier to carbonaceous powder, and from the second time onward, the proportion of the carrier becomes smaller than the weight ratio of the initially precipitated powder. It precipitates out what is present.

That is, first, the carbonaceous powder and the carrier are uniformly deposited on the substrate by using an electrodeposition dispersion having a relatively large weight ratio of the carrier to the carbonaceous powder. And 2
From the second time onward, a large amount can be obtained by precipitating a blending system in which the weight ratio of the carbonaceous powder to the carrier is smaller than that contained in the previous blending system.

In addition, the method of this invention assigns the roles of uniformly depositing the carbonaceous powder and carrier onto the base material and depositing them in large amounts to the respective compounding systems, so that the carbonaceous powder and carrier are precipitated uniformly and in large amounts. It can be done more accurately and in a shorter time than conventional methods.

<Example> Hereinafter, this invention will be explained in detail with reference to Examples.

Example 1 (1) Self-sintering carbonaceous powder and poorly sintered coke powder were mixed at a weight ratio of 2=1, and the average particle size was 5 μ η
T and Shinoko.

(2) The above powder was thoroughly kneaded with a polyacrylonitrile-acrylic acid electrodeposition resin and a solvent, and then dispersed in water to form a so-called anionic coating dispersion. In this state, the ratio of carbon powder to resin was set to three types: 1:5.1:1 and 5:1 in terms of weight ratio.

(3) Next, prepare a polyacrylonitrile carbon fiber cloth, use it as an anode, and use a stainless steel plate as the opposing cathode. Approximately 50V so that the weight ratio of the coating is 1:1
voltage was applied while stirring and mixing thoroughly. Thereafter, electrodeposition was performed using a dispersion liquid of carbon powder:resin-1:1.5:1 such that the ratio of base material:coating was 1:2.1:3. Electrodeposition time was 10 minutes on the gold side.

(4) Laminate 100 sheets of the above electrodeposited body at a temperature of 200°C.
, pressure molding was carried out for 10 minutes at a blood pressure of 20 kg4.

(5) Thereafter, while maintaining the thickness of the molded product, it was heated in the air at 250° C. and 1280° C. for 3 hours to make it infusible.

(6) This infusible material was heated to 500 Kf in an inert atmosphere.
The temperature was raised to 1000°C at a heating rate of 30°C/hr under a blood pressure of iJ, and then to 2000°C at a heating rate of 100°C/hr.
A carbon fiber-reinforced carbon composite material is obtained by backwarming to ℃.
.

Example 2 (1) A polyacrylonyl 1-lyl carbon 11ilf filament yarn was prepared and continuously supplied and immersed in the electrodeposition dispersion of carbon powder:resin-1:5.5:1 used in Example 1. , this is used as an anode, and the stainless steel plate is used as a cathode.
Electrodeposition was carried out by applying a voltage of 0 μ and stirring well. The yarn after electrodeposition was passed through a dryer and dried in an atmosphere of 80°C.

The weight ratio of substrate to coating was 1:4.

(2) Cut the electrodeposited base material yarn into 10 to 50 pieces, fill it in a mold, and tie it at a temperature of 200°C and a surface pressure of 200cm.
Pressure molded for minutes.

(3) The subsequent infusibility and pressure firing were performed under the same conditions as in Example 1, and the carbon fiber-reinforced carbon composite material was dried.

Comparative Example 1 (1) The polyacrylonitrile carbon fiber cloth used in Example 1 was immersed in the 1:1 electrodeposition dispersion of carbon powder:resin used in Example 1, and electrolyzed under the same conditions as Example 1. I got dressed. However, Group I: Coating-1: 2. There was a limit to the amount of coverage of s, and it took more than 30 minutes.

(2) 115 sheets of the above electrodeposited bodies were laminated and pressure molded under the same conditions as in Example 1.

(3) The subsequent infusibility and pressure firing were performed under the same conditions as in Example 1 to obtain a carbon fiber-reinforced carbon composite material having the same dimensions and performance as in Example 1.

Comparative Example 2 (1) The polyacrylonitrile carbon van filament yarn used in Example 2 was immersed in the electrodeposition dispersion used in Comparative Example 1, and electrodeposition was performed under the same conditions as in Example 2.

However, when the current was applied for the same time as in Example 2, the weight ratio of the base material to the coating was only 1:2.6.

Therefore, it took 144 times as much time as in Example 2 to obtain the electrodeposited base yarn with the same small hanging as in Example 2.

(2) The obtained base yarn was cut into pieces of 10 to 50 mm, filled into a mold, and pressure-molded under the same conditions as in Example 2.

(3) The subsequent infusibility and pressure firing were performed under the same conditions as in Example 2, and a carbon fiber-reinforced carbon composite material having the same dimensions and performance as in Example 2 was grown.

<Effects of the Invention> As described above, the present invention was able to uniformly deposit a large amount of carbonaceous powder and carrier on a carbon fiber substrate in a short time by performing electrodeposition on the substrate in multiple stages.

Claims (3)

[Claims] (1) After adsorbing a carrier that can be ionized in a liquid to carbonaceous fine powder, it is dispersed in the liquid, and then a carbon fiber base material and a counter electrode are immersed in the dispersion liquid. A carbon fiber-reinforced carbon is applied between a counter electrode and deposits carbonaceous powder and carrier on a carbon fiber base material to obtain a coating, and this coating is dried, heat-formed, heat-treated, and carbonized. In the method for producing composite materials, when obtaining a coating, firstly a material having a relatively large weight ratio of carrier to carbonaceous powder is precipitated, and from the second time onward, the ratio of the carrier to the carbonaceous powder is higher than the weight ratio of the previously precipitated powder. A method for producing a carbon fiber-reinforced carbon composite material, characterized by precipitating a material that is decreasing. (2) The carbon fiber-reinforced carbon composite material according to claim 1, wherein the carbon fiber base material is a string-like material made of bundled single fibers, a woven fabric, or a paper non-woven fabric. Production method. (3) The carbon fiber-reinforced carbon composite material according to claim 1, wherein the carrier is a resin that can be electrodeposited by modifying a polyacrylonitrile resin derivative or a thermosetting resin derivative. manufacturing method.