JPH0578172A - Super environmental resistant carbon-fiber reinforced composite material and its production - Google Patents

Abstract

PURPOSE:To provide a carbon-fiber reinforced heat-resistant lightweight composite material capable of improving high strength utilizing strength of carbon fiber in a carbon-fiber reinforced carbon composite material and its antioxidizing properties and a method for producing the composite material. CONSTITUTION:The title composite material is a multielement matrix carbon- fiber reinforced composite material obtained by filling ceramics in open cells of a carbon matrix of a carbon-fiber reinforced carbon composite material. The ceramics are filled in the open cells of the carbon matrix by adopting a chemical vapor reaction method. Thereby, the ceramics can continuously be introduced into the fine cells ranging from the interior to the surface. Strength and toughness can further be improved by adopting pulse pressure type chemical vapor reaction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon fiber reinforced composite material having a super-heat resistant and lightweight carbon / ceramic mixed multi-component matrix and a method for producing the same.

[0002]

2. Description of the Related Art As materials for space shuttle nose cones, supersonic transport (HST) outer plates, rocket motor nozzles, high-performance jet engines, gas turbine blades, etc., they are lightweight and have super heat resistance. Structural materials are essential.

Carbon fiber reinforced carbon composite material (hereinafter C / C
Abbreviated as composite. ) Has an unrivaled high heat resistance of up to 2,500 ° C. and is lightweight, and is therefore noted as a lightweight heat resistant structural material for the above purpose.

However, the C / C composite has the following problems under the present circumstances, and there is an urgent need to solve these problems. The problems are: (1) In the C / C composite, the breaking strain of the carbon matrix is smaller than that of the carbon fiber of the reinforcing fiber,
The strength of the reinforcing fiber cannot be fully utilized and the strength is only about 40% of the theoretical strength of the composite material. (2) The C / C composite has remarkably poor oxidation resistance as compared with its heat resistance, and severe oxidative wear occurs from about 400 ° C. in the atmosphere. For this reason, an oxidation resistant coating made of ceramics is indispensable, and research has progressed considerably in recent years, but ceramics coatings are susceptible to damage by impact, and even a slight damage causes significant oxidative wear to the entire material. Therefore, there is a problem in terms of reliability.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of conventional C / C composites as a lightweight heat-resistant structural material, and is highly effective as a composite material utilizing the strength of carbon fibers as reinforcing fibers. It is an object of the present invention to provide a multi-component matrix carbon fiber reinforced heat-resistant lightweight composite material that can obtain strength and high oxidation resistance, and a method for producing the same.

[0006]

In order to solve the above-mentioned problems, the carbon fiber reinforced composite material according to the present invention has one or more kinds inside the pores of a carbon fiber reinforced carbon material substrate having continuous pores as a substrate. It is configured as a carbon fiber reinforced composite material having a mixed multi-component composite material matrix of carbon and ceramics filled with various types of ceramics.

The manufacturing method is as follows: a) carbon fiber is impregnated with resin, carbon fiber reinforced plastic is molded or carbon fiber is melt impregnated with pitch,
A step of forming a carbon fiber reinforced pitch impregnated body, b) firing the formed carbon fiber reinforced plastic or carbon fiber reinforced pitch impregnated body to carbonize the above resin or pitch to obtain a carbon material base material having continuous pores, and carbon A carbonization treatment step for producing a fiber-reinforced carbon material preform, c) filling one or more kinds of ceramics that can be deposited by a chemical vapor phase reaction inside the continuous pores of the carbon material substrate of the above-mentioned carbon fiber-reinforced carbon material preform It is characterized by having a filling step in this order.

[0008]

The carbon fiber reinforced composite material according to the present invention is C / C
Since the ceramics are filled inside the continuous pores of the carbon base material of the composite, the ceramics behave as a matrix for reinforcing fibers and as a reinforcing material for matrix carbons. Sexualization is brought about.

By forming a coating layer on the surface of the above-mentioned carbon fiber reinforced composite material with a ceramic of the same kind as the ceramics filled in the pores, the ceramic coated on the surface functions as an oxidation resistant coating and is resistant to oxidation. Can be improved.

By filling the continuous pores of the carbon base material with the ceramic by the chemical vapor phase filling (CVI) method, the degree of freedom of the material of the ceramic to be introduced is large even in the molding of the multi-component matrix composite material. ,Also,
Ceramics are continuously introduced from the inside to the surface of the C / C composite material, and the heat resistance and oxidation resistance are greatly improved.

By adopting a pulse pressure type chemical vapor phase filling (pulse CVI) method as the chemical vapor phase filling method, ceramics can be filled even in the pores having a depth of several mm and an opening diameter of about 1 μm, and the matrix Can be a multi-element system in which carbon and ceramics are mixed, and high strength and high acid resistance can be obtained.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a flow chart schematically showing the flow of steps for producing the multi-element matrix C / C composite of the present invention. Each step will be described in the order of steps.

A) Molding Carbon fiber is impregnated with resin to mold carbon fiber reinforced plastics (FRP).

B) Carbonization treatment By firing the molded FRP at a predetermined temperature, the resin in the FRP is carbonized to form a carbon matrix having fine continuous pores as shown in the cross section in the figure, A C / C preform that is composite with carbon fibers is formed.

C) CVI (Chemical Vapor Filling) Ceramics are filled into the continuous pores of the carbon matrix of the C / C preform by the CVI method. By this step, as shown in the sectional view, the continuous pores of the carbon matrix are filled with the ceramics to form the multi-dimensional matrix C / C. At this time, the ceramic is continuously introduced from the inside of the C / C composite material to the surface thereof, and a ceramic coating layer is formed on the surface.

FIG. 2 is a diagram showing a schematic configuration of an example of a general CVI device. The C / C preform 1 is supported in a furnace 5, and a reaction gas for depositing a ceramic matrix according to the purpose is introduced from a gas inlet,
After flowing through the continuous pores from one surface of the C / C preform 1 to the other surface, it is discharged from the gas outlet 3. The furnace 5 is heated to a predetermined temperature by the heater 4.

D) Processing The multi-element matrix C / C is machined into the required product.

In the above-mentioned CVI process, by adopting the pulse CVI (pulse pressure type chemical vapor phase filling) method which has been recently developed, ceramics can be rapidly filled even in continuous fine holes having a depth of several mm and an opening diameter of about 1 μm. Can be filled at a high rate,
And the surface can be coated with a ceramic layer. That is, the matrix is a multi-dimensional system in which carbon and ceramics are mixed.

The ceramic filled inside the matrix behaves as a matrix for the reinforcing carbon fibers and as a reinforcing material for the matrix carbon,
Higher strength and higher toughness are brought about by the combined effect. Fine ceramics obtained in recent years have lower toughness than C / C composites, but many are more excellent in strength. When carbon and ceramics are intricately entangled with each other, the ceramic reinforces the carbon to provide higher strength than that of carbon alone and prevent mutual crack growth, resulting in high toughness. Further, an appropriately large breaking strain can be obtained by slipping the interface where carbon and ceramics are entangled with each other.

On the other hand, regarding the oxidation resistance, the ceramics coated on the surface of the material act as an oxidation resistant coating, but since the ceramics coated on the surface are connected to the ceramics filled in the above-mentioned pores, the anchor is formed. High adhesiveness due to the effect. Further, regarding the thermal stress between the coating layer and the base material, the ceramic material is mixed in the base material, so that the value is smaller than that in the case of carbon alone. Further, even if the coating layer is damaged, the oxidation resistance of the base material itself is much higher than that of carbon alone, and the reliability of the entire member is improved.

The decrease in heat resistance due to the filling with ceramics does not pose a practical problem because a ceramic oxidation resistant coating is indispensable for the current C / C composites.

[0023]

As described above, according to the present invention, by introducing ceramics into the continuous pores inside the carbon matrix of the C / C composite, the strength is increased by the composite effect.
High toughness can be achieved. Further, since the ceramics continuously introduced onto the surface functions as an oxidation resistant coating having high adhesiveness, the oxidation resistant property is improved.

Further, by adopting the CVI method for continuously introducing the ceramics from the inside of the carbon matrix to the outer surface, it is possible to quickly fill the fine continuous pores with the ceramics at a high filling rate, and to provide acid resistance and oxidation resistance. It can be expected to improve significantly.

[Brief description of drawings]

FIG. 1 is a flow chart schematically showing a flow of a manufacturing process of a multi-element matrix C / C composite material of the present invention.

FIG. 2 is a cross-sectional view showing a schematic configuration of an example of a general CVI device.

Claims (5)

[Claims] 1. A carbon fiber-reinforced carbon fiber-reinforced carbon material substrate having continuous pores as a substrate, and a carbon-ceramic mixed multi-component composite material substrate in which one or more kinds of ceramics are filled inside the pores. Composite material. 2. The carbon fiber reinforced composite material according to claim 1, wherein the surface of the carbon fiber reinforced composite material has a coating layer of the same kind of ceramics as the ceramics filling the pores. 3. A method for producing a carbon fiber reinforced composite material having a mixed multi-component matrix of carbon and ceramics, comprising: a) impregnating carbon fibers with a resin to mold carbon fiber reinforced plastic or melt impregnating carbon fibers with pitch;
A step of forming a carbon fiber reinforced pitch impregnated body, b) firing the formed carbon fiber reinforced plastic or carbon fiber reinforced pitch impregnated body to carbonize the above resin or pitch to obtain a carbon material base material having continuous pores, and carbon A carbonization treatment step for producing a fiber-reinforced carbon material preform, c) filling one or more kinds of ceramics that can be deposited by a chemical vapor phase reaction inside the continuous pores of the carbon material substrate of the above-mentioned carbon fiber-reinforced carbon material preform A method for producing a carbon fiber reinforced composite material, comprising a filling step in this order. 4. The ceramics filled in the filling step is continuously filled from the inside to the surface of the carbon fiber reinforced carbon material preform, and a ceramic coating layer is formed on the surface. The method for producing a carbon fiber reinforced composite material according to claim 3. 5. The method for producing a carbon fiber reinforced composite material according to claim 3, wherein the chemical vapor phase reaction in the filling step is a pulse pressure chemical vapor phase reaction.