JPH0761688B2 - Repair method of carbon fiber reinforced carbon composite material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for repairing a carbon fiber reinforced carbon composite material.

[Prior Art and Problems] At present, since there is no bonding technology for carbon fiber reinforced carbon composite materials, the composite materials that have been rubbed, worn or consumed have to be discarded. Since this kind of composite material is very expensive, it is a great economical loss.

Such carbon fiber reinforced carbon composite materials are used, for example, in automobile disc brake pads.

[Structure of the Invention] The present invention has been made for the purpose of repairing a carbon fiber reinforced carbon composite material having a thin plate thickness such as friction, wear, or wear, and electrodeposition is performed on the surface of the carbon fiber reinforced carbon composite material. Method to deposit carbonaceous powder and carrier, and then deposit carbonaceous powder and carrier on carbon fiber by the same electrodeposition method. This is a method of repairing a carbon fiber reinforced carbon composite material in which carbonaceous powder and a carrier are deposited on the surface of a carbon composite material by using an electrodeposition method, and the carbon fiber reinforced carbon composite material is fired after being integrated by pressing and heating.

Such a repairing method is made by paying attention to the application of the electrodeposition method because the carbon fiber and the composite material thereof have conductivity.

The method of the present invention is as follows. That is, a carrier which can be ionized in a liquid is adsorbed to the carbonaceous fine powder and then dispersed in the liquid.

Thereafter, the plate thickness is reduced by friction, wear, or consumption, or the carbon fiber-reinforced carbon composite material originally having a thin plate thickness and the counter electrode are immersed in the dispersion liquid, and the composite material and the counter electrode are placed between the composite material and the counter electrode. A DC voltage is applied to deposit the carbonaceous fine powder and the carrier on the surface of the composite material.

On the other hand, a carbon fiber base material is immersed in the dispersion liquid, a direct current voltage is applied between the carbon fiber base material and the counter electrode, and carbon powder and a carrier are deposited on the surface of the carbon fiber base material to obtain a coating.

The carbon fiber reinforced composite material and the carbon fiber base material coated in this manner are dried, overlapped and integrated by pressure / heat molding, and then carbonized and fired.

Since the carbon fiber reinforced carbon composite material has conductivity, it is possible to firmly adhere the carbonaceous powder and the resin by using the carrier that can be ionized in the liquid, and therefore the carbon fiber coated with the carbon powder or the resin is used. 300-900 ℃ when reinforced composite material and coated carbon fiber are integrally molded by pressure and heating and then fired
The carbonaceous powder softens in the meantime, and the fired product becomes an integrated carbon fiber reinforced composite material due to the wetting of the interface and the chemical reaction.

As the carbon fiber base material, a string-like material obtained by bundling single fibers, a woven fabric, or a paper-like non-woven fabric can be used, and the carrier is modified by modifying a polyacrylonitrile resin derivative or a thermosetting resin derivative. A resin that can be attached is used.

Examples will be described below.

[Example 1] (1) The surface of the carbon fiber reinforced composite material that was rubbed and worn was surface-ground to obtain the parallelism of the surface. (Shape φ250 × t7m
m) (2) After that, the surface was appropriately roughened so as to facilitate electrodeposition.

(3) On this carbon fiber reinforced composite material, a self-sintering carbonaceous powder and a carrier resin formed an electrodeposition coating in a weight ratio of 1: 1.

(4) Also, a self-sintering carbon powder, a carrier resin, and a carbon fiber cloth in a weight ratio of 1: 250 with a diameter of 250 are applied by electrodeposition.
Sheets were made and molded with the coated carbon fiber reinforced carbon composite material. By heating at a temperature of 200 ℃ and a pressure of 20kg / cm ² for 10 minutes.

(5) These compacts were heated in the atmosphere at 250 ° C. and 280 ° C. for 3 hours, respectively, while being clamped with a 3-mesh wire net, to perform heat treatment.

(6) The heat-treated body was heated in an inert atmosphere at 500 kg / cm ² under surface pressure to 2000 ° C. at a temperature rising rate of 30 ° C./hour to fire a carbon fiber-reinforced carbon composite material.

[Example 2] (1) Two sheets of the electrodeposited carbon fiber reinforced carbon composite material produced in item (3) of example 1 were stacked and integrally molded under the conditions of item (4) of example 1.

(2) Then, heat treatment and pressure firing were performed under the same conditions as in Example 1.

[Comparative Example] (1) Using the self-sintering carbon powder, the carrier resin, and the carbon fiber woven cloth used in the above examples, 150 sheets of φ250 coating having a weight ratio of 1: 1 were prepared. did.

(2) Under the same conditions as in the examples, molding by pressure / heating, heat treatment, and pressure firing were performed to obtain a carbon fiber-reinforced carbon composite material.

Table 1 shows the physical property values of the materials obtained in Examples and Comparative Examples.

As is clear from Table 1, even if repair is performed, the composite material is slightly inferior to the original composite material, but there is no practical problem.

[Advantages of the Invention] According to the present invention, when a carbon fiber reinforced carbon composite material that has been rubbed, worn or exhausted is reused, the bending strength and the Charpy impact value are slightly inferior, but there is no problem in practical use and they have been discarded until now. The carbon fiber reinforced carbon composite material can be reused, which is economically very effective.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location D06M 11/00 B

Claims (2)

[Claims] 1. A carbonaceous powder and a carrier are deposited on the surface of a carbon fiber-reinforced carbon composite material having a thin plate thickness by friction, wear, or consumption, or a thin plate, and carbon fibers are deposited on the carbon fiber powder and the carrier by the electrodeposition method. A method for repairing a carbon fiber reinforced carbon composite material, which comprises stacking a coating material on which a carbonaceous powder and a carrier are deposited, integrating them by pressurizing and heating, and then firing. 2. A carbon fiber reinforced carbon composite material having a thin plate thickness, which is frictional, worn, or worn, or has a thin plate on which carbonaceous powder and a carrier are deposited by an electrodeposition method. A method for repairing a carbon fiber-reinforced carbon composite material, which comprises firing after being integrated.