JP2005082876A - Carbon fiber reinforced aluminum based composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a carbon fiber reinforced aluminum based composite material in which joining strength between carbon fiber and aluminum or an aluminum alloy as a base material is increased and the effect of improving the mechanical strength in the carbon fiber is sufficiently exhibited, and which has high mechanical strength. <P>SOLUTION: A metallic layer 5 consisting of a plurality of metallic layers 6 and 7 is formed on the surface of carbon fiber 4. The metallic layer 6 in contact with the carbon fiber 4 is composed of a first metal capable of forming a sound solid solution with carbon. The metallic layer 7 in contact with the base material 2 comprises the first metal and a second metal capable of forming a sound solid solution with the base material, and the compositional ratio between the first metal and the second metal is transitionally changed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a carbon fiber reinforced aluminum-based composite material that is reinforced by using aluminum or an aluminum alloy as a base material and mixing metal-coated carbon fibers in the base material.

  Realization of lightweight and high-strength materials enables, for example, building materials to be used to make effective use of land by building high-rise structures, and fuel for materials such as vehicles and aircraft. Various attempts have been made to save money.

  One of the attempts is to reduce the weight and increase the strength by using a composite material, and for example, fiber reinforced plastic (abbreviated as FRP) is well known. In general FRP, an epoxy resin is used as a matrix (base material), and reinforcing fibers such as carbon fibers are mixed in the base material. However, FRP based on epoxy resin has a low heat-resistant temperature of about 200 ° C., so there is no problem in applications at room temperature, for example, water storage tanks, but it is like a member exposed to high temperatures of automobiles. There is a problem that it cannot be applied to various uses.

  For such a problem, there is FRP having a heat-resistant temperature increased by using a thermoplastic resin such as polyether ether ketone or polyimide as a base material, but the heat-resistant temperature is about 400 ° C. at most. However, since the resin is expensive, it is inferior in versatility.

Therefore, for applications such as members exposed to high temperatures of automobiles, the development of composite materials based on metals has been attempted, and among the metals for substrates, the specific gravity is small and suitable for weight reduction, Aluminum is also attracting attention because of its excellent workability, corrosion resistance, and thermal conductivity. However, when carbon fibers such as PAN-based carbon fibers are added to the base aluminum, the aluminum and carbon fibers react to form aluminum carbide (probably Al ₄ C ₃ and / or a compound of aluminum and carbon). or because Al ₂ C ₂ to be estimated) is formed, and significantly reduced the strength of the carbon fiber, there is a problem that not give them to serve as reinforcement.

  In the prior art for solving such problems, a molten salt solidified layer of fluoride group is formed on the surface of carbon fiber or a fluoride group layer is formed on the surface of the carbon fiber to inhibit the compound formation of aluminum and carbon, and aluminum In contrast, there is a material that exhibits good wettability (see, for example, Patent Document 1). As another conventional technique, there is a technique in which a silicon dioxide layer is formed on the surface of a carbon fiber and good wettability is expressed with respect to aluminum (for example, see Patent Document 2).

  However, the techniques disclosed in Patent Document 1 and Patent Document 2 provide a carbon fiber surface by providing a coating layer having a surface roughness larger than that of the carbon fiber surface and increasing the contact area with aluminum, It merely improves the wettability with aluminum and does not improve the bonding state at the interface between carbon fiber and aluminum. In addition, the thermal expansion coefficients of carbon fiber, the coating layer provided on the surface of the carbon fiber, and aluminum or aluminum alloy as a base material are often greatly different. Peeling tends to occur at the interface between the layer and the substrate. Therefore, there is a problem that it is difficult to realize sufficient strength to substitute for a member application in which a conventional iron-based alloy material is used, such as the above-described application of the automobile member exposed to a high temperature. is there.

Japanese Patent Laid-Open No. 5-125662 JP 2002-59257 A

  An object of the present invention is a carbon fiber reinforced aluminum-based composite material including carbon fibers having a metal layer on the surface as a reinforcing material, which is equivalent to or higher than a metal material even when exposed to high temperatures of several hundred degrees or more. It is to provide a carbon fiber reinforced aluminum matrix composite material exhibiting a high mechanical strength.

  The inventors of the present invention have (1) forming a coating layer having a laminated structure of a plurality of metal layers on the surface of carbon fiber, and (2) forming a metal layer in contact with the carbon fiber with a solid solid solution (causing interfacial peeling). (3) a metal layer that is in contact with aluminum or an aluminum alloy that is a base material of a carbon fiber reinforced aluminum matrix composite material, the first metal, and In the case where the composition includes a base material and a second metal that forms a sound solid solution, and the composition ratio of the first metal and the second metal changes transitionally, the carbon fiber and the metal in contact with the carbon fiber From the interface with the layer to the interface between the base material and the metal layer in contact with it, a continuous layer with no sudden changes in physical properties is formed, and an inclined interface is realized, thus increasing the bond strength between the carbon fiber and the base material Focusing on the fact that the present invention And it has reached.

That is, the present invention uses a base material made of aluminum or an aluminum alloy, and a carbon fiber reinforced aluminum-based composite material reinforced by mixing metal-coated carbon fibers in the base material,
Metal-coated carbon fiber is
A first layer comprising nickel or a nickel alloy formed in contact with the surface of the carbon fiber;
A metal layer containing nickel and copper formed in contact with the surface of the first layer, the second layer being a composition transition layer in which the composition ratio of nickel and copper changes continuously or stepwise A carbon fiber-reinforced aluminum-based composite material, characterized in that it is a metal-coated carbon fiber having a coating layer composed of

In the present invention, the metal-coated carbon fiber is
A first layer comprising nickel or a nickel alloy formed in contact with the surface of the carbon fiber;
A second layer, which is a metal layer containing nickel and copper formed in contact with the surface of the first layer, and is a composition transition layer in which the composition ratio of nickel and copper changes continuously or stepwise;
A carbon fiber reinforced aluminum-based composite material, characterized in that it is a metal-coated carbon fiber having a coating layer comprising a third layer containing copper or a copper alloy formed in contact with the surface of the second layer. is there.

  Further, the present invention is characterized in that the composition ratio of nickel and copper in the third layer transitions so that the composition ratio of copper increases as the distance from the first layer increases in the layer thickness direction.

  Moreover, the present invention is characterized in that the coating layer of the metal-coated carbon fiber is formed by plating.

  In the present invention, the metal-coated carbon fiber is heat-treated at 500 ° C. or more and 1000 ° C. or less in a non-oxidizing atmosphere after the coating layer is formed.

In the present invention, the carbon fiber is
One or more selected from PAN-based carbon fiber, pitch-based carbon fiber and vapor-grown carbon fiber,
The ratio of the fiber diameter D to the fiber length L (D / L) is 1/100000 or less.

  Further, the present invention is characterized in that the metal-coated carbon fiber is formed by being charged into a molten aluminum or aluminum alloy in a non-oxidizing atmosphere.

  Further, the present invention is characterized in that the content of the metal-coated carbon fiber is 5% or more and 70% or less by volume.

  According to the present invention, the carbon fiber is covered with a plurality of layers, at least two metal layers. Since nickel or a nickel alloy contained in the first layer of the metal-coated carbon fiber forms a solid solution with carbon constituting the carbon fiber, an interface between the carbon fiber and the first layer having excellent bond strength is formed. The second layer is a composition transition layer in which the composition ratio of nickel and copper changes continuously or stepwise with a gentle gradient. Preferably, the composition ratio of copper moves away from the first layer in the layer thickness direction. Therefore, the ratio of copper increases on the surface in contact with the base material of the second layer, and this copper forms a solid solution with the base material aluminum or aluminum alloy, and has excellent bond strength. An interface between the second layer and the substrate is formed.

  Further, by providing a third layer made of copper or a copper alloy on the surface of the second layer, the copper exposed to be more than nickel on the surface of the second layer and the copper or copper alloy of the third layer form a solid solution. The third layer of copper or copper alloy and the base material form a solid solution, so that the carbon fibers are more firmly fixed in the base material.

  From such an interface between the carbon fiber and the first layer to an interface between the base material and the second layer or the third layer, there is no continuous physical property change, and a continuous interface between the continuous layers, a so-called inclined interface. Therefore, the bond strength at the interface is remarkably increased, and peeling between Al as the base material and carbon fiber as the reinforcing material hardly occurs, and a lightweight and high-strength carbon fiber reinforced aluminum-based composite material is obtained. Realized.

  According to the invention, the coating layer of the metal-coated carbon fiber is formed by plating. Plating is a coating layer forming means that can be carried out without requiring large equipment. In addition, the plating can easily control the thickness of the layer covering the carbon fiber and the component composition of the layer. Therefore, according to the plating, the metal-coated carbon fiber can be formed with high accuracy at low cost.

  According to the present invention, since the metal-coated carbon fiber is heat-treated at 500 ° C. or more and 1000 ° C. or less in a non-oxidizing atmosphere after the coating layer is formed, the interface between the carbon fiber and the first layer The solid solution formation in the interface between the aluminum and the second layer or the third layer is surely performed. As a result, the degree of change in physical properties in the interface and the layer is further relaxed and the bond strength is improved, so that the separation between the aluminum and the carbon fibers is further suppressed, and the strength of the carbon fiber reinforced aluminum-based composite material is improved.

  According to the invention, the carbon fiber is one or more selected from PAN-based carbon fiber, pitch-based carbon fiber, and vapor-grown carbon fiber, and has a fiber diameter D with respect to the fiber length L. The ratio (D / L) is 1/100000 or less. Since these carbon fibers are commercially available and are available in large quantities, the versatility of the carbon fiber reinforced aluminum matrix composite can be enhanced. Moreover, since the orientation of carbon fiber can be improved by setting the ratio (D / L) within a suitable range, the strength of the carbon fiber-reinforced aluminum-based composite material can be further improved.

  According to the invention, the carbon fiber reinforced aluminum matrix composite is formed by charging the metal-coated carbon fiber into aluminum or an aluminum alloy in a molten state in a non-oxidizing atmosphere. As a result, since copper and aluminum mutually diffuse to form a solid solution at a temperature higher than the melting point of aluminum, it becomes possible to improve the bonding strength between the second layer or the third layer and aluminum. .

  Further, according to the present invention, the content of the metal-coated carbon fiber is set in a suitable range, so that a carbon fiber-reinforced aluminum-based composite material having excellent strength is realized.

  The carbon fiber reinforced aluminum matrix composite of the present invention contains metal-coated carbon fibers in the base material.

  FIG. 1 is a cross-sectional view of an essential part schematically showing a configuration of a carbon fiber reinforced aluminum matrix composite material according to a first embodiment of the present invention.

  The carbon fiber reinforced aluminum matrix composite 1 is configured by including a metal-coated carbon fiber 3 in a base material 2. The metal-coated carbon fiber 3 is obtained by forming a metal layer 5 on the surface of the carbon fiber 4, and the metal layer 5 includes a first layer 6 formed on the surface of the carbon fiber 4 and a surface of the first layer 6. And the second layer 7 formed. A solid solution layer 9 a is formed at the interface between the carbon fiber 4 and the first layer 6. A solid solution layer 9 b is formed at the interface between the first layer 6 and the second layer 7. A solid solution layer 9 c is formed at the interface between the second layer 7 and the substrate 2. Since the carbon fiber 4, the first layer 6, the second layer 7, and the base material 2 are firmly bonded by the solid solution layers 9 a, 9 b, 9 c formed at the respective interfaces, the carbon fiber 4 is stable to the base material 2. The effect of improving the mechanical strength of the carbon fiber 4 is sufficiently exhibited.

  FIG. 2 is a cross-sectional view of an essential part schematically showing the configuration of the carbon fiber reinforced aluminum matrix composite material according to the second embodiment of the present invention.

  The carbon fiber reinforced aluminum matrix composite material 10 is configured to include metal-coated carbon fibers 11 in the base material 2. The metal-coated carbon fiber 11 is obtained by forming a metal layer 12 on the surface of the carbon fiber 4, and the metal layer 12 includes a first layer 6 formed on the surface of the carbon fiber 4 and a surface of the first layer 6. And the third layer 12 formed on the surface of the second layer 7. Similarly to the metal-coated carbon fiber 3, solid solution layers 9a and 9b are formed at the interfaces of the carbon fiber 4, the first layer 6 and the second layer 7, respectively. Further, a solid solution layer 9 d is formed at the interface between the second layer 7 and the third layer 12, and a solid solution layer 9 e is formed at the interface between the third layer 12 and the substrate 2. Since the carbon fiber 4, the first layer 6, the second layer 7, the third layer 8, and the base material 2 are firmly bonded via the solid solution layers 9 a, 9 b, 9 d, 9 e, the carbon fiber 4 is attached to the base material 2. It is stably fixed, and the effect of improving the mechanical strength of the carbon fiber 4 is sufficiently exhibited.

  The base material 2 is aluminum or an aluminum alloy. Known aluminum alloys can be used, such as aluminum-copper, aluminum-zinc, aluminum-manganese, aluminum-magnesium, aluminum-magnesium-manganese, aluminum-magnesium-silicon, aluminum-silicon, and aluminum-copper-magnesium. , Aluminum-zinc-magnesium, aluminum-zinc-magnesium-copper and the like. The base material 2 is appropriately selected according to the use of the obtained carbon fiber reinforced aluminum matrix composite material 10.

  As the carbon fiber 4 that is a core material of the metal-coated carbon fibers 3 and 11, known carbon fibers 4 can be used. For example, pitch-based carbon fiber, liquid crystal-based carbon fiber, rayon-based carbon fiber, PAN-based carbon fiber, vapor phase-grown system Examples thereof include carbon fiber. Among these, pitch-based carbon fiber, PA-based carbon fiber, vapor-grown carbon fiber, and the like are preferable in consideration of tensile strength, tensile elastic modulus, and the like. A carbon fiber can be used individually by 1 type, or can use 2 or more types together. The fiber diameter of the carbon fiber is not particularly limited and can be appropriately selected from a wide range, but is usually about 0.1 to 30 μm, preferably about 3 to 10 μm. Among the carbon fibers having such a fiber diameter, those having a ratio of the fiber diameter D to the fiber length L (D / L) of 1/100000 are preferable. Thereby, since the orientation of the metal-coated carbon fiber in the substrate can be increased, the mechanical strength of the carbon fiber-reinforced aluminum composite material of the present invention can be further increased.

  Moreover, the above-mentioned carbon fiber can be used as a filament yarn composed of a plurality of filaments, and a carbon fiber spread yarn obtained by opening the filament yarn according to a known method can be used. The number of filaments in the carbon fiber spread yarn is not particularly limited and can be appropriately selected from a wide range, but is usually about 1000 to 50000, preferably about 12000 to 48000. The width of the carbon fiber spread yarn is not particularly limited and can be appropriately selected from a wide range. Usually, the width of the cross section is 8 to 60 mm, preferably 10 to 50 mm, and the degree of spread (cross section of the spread yarn) (Thickness / width of spread yarn cross section) is usually 0.05 or less, preferably 0.01 or less, more preferably 0.0005 to 0.01. Commercially available carbon fiber spread yarn may be used, for example, Torayca (registered trademark, manufactured by Toray Industries, Inc.), Pyrofil (registered trademark, manufactured by Mitsubishi Rayon), Besfight (registered trademark, Toho Rayon (Ltd.)) )), Granock (registered trademark, manufactured by Nippon Graphite Fiber Co., Ltd.), and the like.

  Furthermore, a woven fabric or a nonwoven fabric made of carbon fiber may be used. Non-woven fabric includes unidirectional fabric and the like. The unidirectional fabric is also called, for example, a unidirectional reinforcing fiber sheet or a unidirectional reinforcing fiber material.

The fabric made of carbon fiber is not particularly limited, and for example, the basis weight is usually 50 to 320 g / m ² , preferably 70 to 300 g / m ² , and the thickness is usually 0.02 to 0.8 mm, preferably 0.00. The thing of 08-0.2 mm is used.

The unidirectional fabric made of carbon fiber is not particularly limited. For example, the basis weight is usually 20 to 125 g / m ² , preferably 30 to 85 g / m ² , and the thickness is usually 0.01 to 0.2 mm, preferably 0.00. The thing of 05-0.1 mm is used.

  Among these, in consideration of the mechanical strength of the obtained carbon fiber reinforced aluminum matrix composite material, carbon fiber spread yarn, fabric made of carbon fiber spread yarn, non-woven fabric, etc. are preferable, and fabric made of carbon fiber spread yarn Particularly preferred is a nonwoven fabric.

  The first layer 6 coated on the surface of the carbon fiber 4 is a metal layer containing nickel or a nickel alloy, preferably nickel. Known alloys can be used as the nickel alloy, and examples thereof include nickel-copper, nickel-chromium, nickel-iron, and nickel-phosphorus. A nickel alloy can be used individually by 1 type, or can use 2 or more types together as needed.

  The second layer 7 formed on the surface of the first layer 6 is a metal layer configured by laminating a large number of thin layers containing nickel and copper and having different composition ratios of nickel and copper. The composition ratio of nickel and copper in each thin layer varies continuously or stepwise. Preferably, as the distance from the first layer 6 increases in the layer thickness direction, the composition ratio of copper increases. That is, it is preferable to change so that the composition ratio of nickel increases as it approaches the first layer 6 and so that the composition ratio of copper increases as it approaches the substrate 2 or the third layer 12.

  In the metal-coated carbon fiber 11, the third layer 8 formed on the surface of the second layer 7 contains copper or a copper alloy, and is preferably a metal layer containing copper. A well-known thing can be used as a copper alloy, For example, copper-silver, copper-cadmium, copper-chromium, copper-beryllium, copper-aluminum, copper-nickel etc. are mentioned.

  The method for forming the metal layers 5 and 12 on the carbon fiber 4 is not particularly limited. For example, a solution reaction method (sol-gel method) in which a carbon fiber and a metal-containing compound are reacted in a solvent, carbon fiber and a metal-containing material. Examples thereof include a method of mixing a compound and heat-treating the mixture in an oxidizing atmosphere, a plating method, and the like. Among these, the plating method is preferable in consideration of increasing the continuity of the composition change in the second layer 7 and forming the metal layer 5 having a better inclined interface.

  According to the plating method, the metal layers 5 and 12 of the metal-coated carbon fibers 3 and 11 can be formed, for example, as follows.

The first layer 6 can be formed by performing nickel plating or nickel alloy plating on the surface of the carbon fiber 4. Nickel plating and nickel alloy plating can be performed by either electrolytic plating or electroless plating. However, considering the plating efficiency of increasing the thickness of the metal layer obtained per unit time, electrolytic plating is performed. preferable. As the nickel plating bath, known ones can be used, and examples thereof include an aqueous solution containing a reducing agent, a complexing agent, a pH adjusting agent, a pH buffering agent, a stabilizer, a stress relaxation agent and the like as necessary together with a nickel salt. . As the nickel salt, those commonly used in this field can be used. For example, nickel sulfate, nickel chloride, nickel nitrate, nickel carbonate, nickel sulfamate, nickel formate, nickel acetate, nickel oxalate, nickel methanesulfonate, 2-hydroxy Examples include nickel propane sulfonate, nickel phenol sulfonate, and nickel borofluoride. Known reducing agents can be used, and examples thereof include phosphorus reducing agents such as sodium hypophosphite and boron reducing agents such as dimethylamine borane. As the complexing agent, known ones can be used, and examples thereof include organic acids such as pyrophosphoric acid, citric acid, lactic acid and ethylenediaminetetraacetic acid, and salts thereof, glycine and the like. Known pH buffering agents can be used, and examples thereof include boric acid. Specific examples of such a nickel plating bath include, for example, a watt bath, a sulfamic acid bath, a copper pyrophosphate bath, and the like. As a nickel alloy plating bath, what added the 1 type (s) or 2 or more types chosen from the compound containing the metal which can be alloyed with nickel to the said nickel plating bath is mentioned, for example. The compound containing a metal that can be alloyed with nickel is not particularly limited, and examples thereof include compounds containing copper, chromium, iron, phosphorus, and the like. For example, in the case of a watt bath, the electrolytic plating is performed by energizing so that the current density is 0.1 to 100 A / dm ² at a plating bath temperature of about 40 to 60 ° C. and a plating bath pH of about 3 to 5. . In addition, in the case of using a woven fabric containing carbon fiber, a unidirectional fabric, or the like as a material for forming the plating film that is the first layer 6, in order to form a plating film that is uniform and has high bonding strength with the carbon fiber, It is preferable to remove the sizing agent adhering to the surface with an organic solvent such as methyl ethyl ketone or acetone.

The second layer 7 can be formed by performing copper-nickel plating on the surface of the first layer 6. Although copper-nickel plating can be carried out by either electrolytic or electroless methods, electrolytic plating is preferable in consideration of plating efficiency. A well-known thing can be used as a copper-nickel plating bath, The aqueous solution containing a complexing agent, a pH adjuster, a reducing agent, a pH buffering agent, etc. is mentioned with nickel salt and copper salt. The same nickel salt as described above can be used. As the copper salt, those commonly used in this field can be used. For example, copper pyrophosphate, copper sulfate, cyan copper, cupric chloride, copper nitrate, basic copper carbonate, copper sulfamate, copper acetate, copper oxalate , Copper methanesulfonate, copper 2-hydroxypropanesulfonate, copper phenolsulfonate, copper borofluoride and the like. As the complexing agent, known ones can be used, and examples thereof include pyrophosphoric acid, tartaric acid, ethylenediaminetetraacetic acid and the like. A well-known thing can be used also as a pH adjuster, For example, ammonium salt, sodium hydroxide, etc. are mentioned. Examples of the reducing agent include formaldehyde. A known pH buffering agent can be used, and examples thereof include tetraboric acid. Further, the copper-nickel plating bath may contain a bath stabilizer, a brightener and the like. Specific examples of the copper-nickel plating bath include, for example, a copper pyrophosphate bath. The electrolytic plating is performed in the same manner as the nickel plating or nickel alloy plating of the first layer 6. For example, in the case of a copper pyrophosphate bath, it is carried out by energizing at a plating bath temperature of about 40-60 ° C. and a plating bath pH of about 8-10 so that the current density is 0.1-100 A / dm ² . In order to form the second layer 7 as a laminate of a plurality of thin layers having different composition ratios of copper and nickel, plating may be performed while appropriately changing the plating conditions. For example, the copper composition is not added to the plating bath at the start of plating, but a certain amount of copper salt is added to the plating bath at regular intervals, so that the closer to the first layer 6, the higher the nickel composition ratio is. As the material 2 or the third layer 8 is closer, the second layer 7 is formed in which the copper composition ratio increases.

  The third layer 8 can be formed by performing copper or copper alloy plating on the surface of the second layer 7. The copper plating and the copper alloy plating are the same as the formation of the first layer 6 and the second layer 7. Although both electrolytic and electroless methods can be used, in consideration of plating efficiency, electrolytic plating is preferable. A well-known thing can be used as a copper plating bath, and the aqueous solution containing a complexing agent, a pH adjuster, a reducing agent, a pH buffering agent etc. is mentioned with copper salt. As the copper salt, complexing agent, pH adjusting agent, reducing agent and pH buffering agent, the same copper-nickel plating bath used for forming the second layer 7 can be used. Specific examples of the copper plating bath include a copper sulfate bath, a cyan copper bath, and copper pyrophosphate. As a copper alloy plating bath, what added the 1 type (s) or 2 or more types chosen from the compound containing the metal which can be alloyed with copper to the said copper plating bath is mentioned, for example. The compound containing a metal that can be alloyed with copper is not particularly limited, and examples thereof include compounds containing silver, cadmium, chromium, beryllium, cobalt, zinc, tin, nickel, and the like. Electrolytic plating can be performed in the same manner as known electrolytic copper plating or electrolytic copper alloy plating.

  In this way, the metal layers 5 and 12 composed of two or three layers are formed on the surface of the carbon fiber 4.

  In the present invention, the metal-coated carbon fibers 3 and 11 obtained above may be heat-treated. The heat treatment is performed at a temperature of 500 to 1000 ° C. in a non-oxidizing atmosphere such as argon gas or nitrogen gas, and is completed in about 15 to 200 minutes. By performing the heat treatment, solid solution formation is reliably performed in the interface between the carbon fiber 4 and the metal layers 5 and 12 and in the metal layers 5 and 12, and the separation between the carbon fiber 4 and the metal layers 5 and 12 is further suppressed. The As a result, when impregnating the aluminum or aluminum alloy which is the base material 2 in the composite material of the present invention into the preform formed of the metal-coated carbon fibers 3 and 11, the base material 2 and the metal-coated carbon fibers 3 and 11 The copper-nickel alloy constituting the second layer 7 of the metal layers 5 and 12 or the copper or copper alloy constituting the third layer 8 forms a solid solution and is firmly bonded, and the carbon fiber 4 and the metal layer 5 , 12 does not occur, so that the carbon fiber 4 is stably held in the base material 2 and the reinforcing effect by the carbon fiber 4 is sufficiently exhibited.

  In producing the composite material of the present invention using this metal-coated carbon fiber, first, a preform is prepared. For example, metal-coated carbon fibers can be woven using warps and / or wefts, and the resulting woven fabric can be used as a preform. The weaving is performed using a known loom such as a rapier loom, a shuttle loom, a gripper loom, or a jet loom. Further, the non-woven fabric such as a unidirectional fabric can be prepared by drawing the metal-coated carbon fibers in one direction so that the adjacent ones overlap each other, and this can be used as a preform. The basis weight and thickness of the woven fabric and non-woven fabric may be the same as those of the above-described carbon fiber woven fabric and non-woven fabric.

  Moreover, you may produce a preform according to the general method for creating a preform in a molten metal forging method using a metal-coated carbon fiber. For example, a metal-coated carbon fiber, a binder such as polyvinyl alcohol, an excipient such as silica sol, an appropriate amount of water, etc. are mixed, and the resulting slurry is put into a mold and pressed into a predetermined shape, and if necessary The preform can be obtained by drying. At this time, the amount of each component used is not particularly limited and can be appropriately selected from a wide range depending on the fiber diameter and fiber length of the metal-coated carbon fiber, the use of the carbon fiber reinforced aluminum-based composite material to be obtained, etc. The amount of the binder used is preferably about 1 to 3% by volume of the total amount of the metal-coated carbon fiber.

  When a metal layer is coated on a woven fabric or nonwoven fabric made of carbon fiber spread yarn, it can be used as a preform as it is.

  The preform used in the present invention has other inorganic reinforcing fibers such as carbon fiber, potassium titanate fiber, aluminum borate fiber, and magnesium borate fiber that are not coated with metal as long as the preferred characteristics are not impaired. Etc. may be included.

  When the preform thus obtained is impregnated with a molten aluminum or aluminum alloy, it can be carried out in the same manner as the conventional molten forging method.

  When the preform is impregnated with the molten metal, the preform is first preheated to 700 to 1000 ° C., preferably 750 to 800 ° C., and then placed in a mold for molten metal forging that is similarly preheated. If it is less than 700 ° C., impregnation of the molten metal into the preform does not proceed smoothly, and there is a possibility that a carbon fiber reinforced aluminum-based composite material having non-uniform mechanical strength, physical properties, etc. may be obtained. If the temperature is significantly higher than 1000 ° C., the metal components in the metal layer of the metal-coated carbon fiber are interdiffused, thereby damaging the inclined interface in the metal layer and reducing the mechanical strength improvement effect of the metal-coated carbon fiber. There is a fear. The preheating time is not particularly limited, and the time for heating uniformly to the inside of the preform may be appropriately selected. The preheating can be performed in air, or can be performed in an inert gas such as argon gas or nitrogen gas as necessary.

  Next, a molten aluminum or aluminum alloy is supplied to the mold on which the preheated preform is placed, the preform is brought into contact with the molten metal, and a press device is used via a presser (pressing punch). Then, pressure is applied to the molten metal and the preform is impregnated with the molten metal. The amount of impregnation of the molten metal is not particularly limited and can be appropriately selected from a wide range. However, considering the mechanical strength, cutting workability, lightness, etc. of the obtained composite material, the metal-coated carbon fiber is usually 5% of the total amount of the composite material. What is necessary is just to impregnate a molten metal so that it may contain -70 volume%, Preferably 35-55 volume%. The temperature of the molten metal is preferably about 50 to 450 ° C. higher than the melting point of aluminum or aluminum alloy. The pressure may be a pressure at which the molten metal is sufficiently impregnated into the preform, and is usually 30 to 120 MPa, preferably 70 to 100 MPa. The impregnation time can be appropriately selected from a wide range depending on the size and density of the preform, the type of the molten metal, etc., but is usually 3 to 20 minutes, preferably 5 to 10 minutes.

  By cooling after the impregnation of the molten metal, a bonded body in which the carbon fiber reinforced aluminum matrix composite material and the solidified body of the molten metal not impregnated are integrated is obtained. By removing the joined body from the mold and removing the solidified body of the molten metal according to a known method such as cutting and melting, the carbon fiber reinforced aluminum matrix composite material of the present invention can be obtained.

  The carbon fiber reinforced aluminum matrix composite of the present invention can be used in applications where conventional carbon fiber reinforced aluminum matrix composites are used and other applications. Specific examples of applications include parts materials for transportation equipment such as automobiles and aircraft, parts materials such as artificial satellites and space development rockets, parts materials such as robot arms and steppers, electronic parts materials, heat dissipation board materials, and architectures. Materials (for example, wall materials), soldering iron materials, etc. are mentioned.

The present invention will be specifically described below with reference to production examples, examples and test examples.
(Production Example 1)
A 100 mm × 100 mm × 0.1 mm carbon fiber woven fabric (carbon fiber opening width 24 mm, woven fabric weight 70 g / m ² ) was immersed in methyl ethyl ketone for 2 minutes at room temperature to dissolve and remove the sizing agent in the carbon fiber woven fabric. . The carbon fiber fabric was taken out from methyl ethyl ketone and dried.

  This carbon fiber woven fabric is subjected to nickel plating, copper-nickel alloy plating and copper plating in order according to the following conditions to form a metal-coated carbon fiber woven fabric having a 2.5 μm thick metal layer containing copper and nickel Manufactured.

  FIG. 3 is a graph showing changes in the composition of the metal layer in the metal-coated carbon fiber. In FIG. 3, the film thickness means the thickness of the metal layer that is laminated outwardly from the interface where the interface between the carbon fiber and the metal layer is “0”. From FIG. 3, the thickness of the nickel plating layer (first layer) is about 0.5 μm, the thickness of the copper-nickel alloy plating layer (second layer) is about 1.5 μm, and the thickness of the copper plating layer (third layer). Is 0.5 μm.

(1) Nickel plating Plating bath composition: Nickel sulfate 240 g / l
Nickel chloride 50g / l
Boric acid 40g / l
Plating bath pH: 4 (adjusted with sulfuric acid)
Plating bath temperature: 50 ° C
Anode: Nickel plate Plating current value: 1A
Plating time: 15 minutes (2) Copper-nickel alloy plating Plating bath composition:
Copper pyrophosphate 0-3 g / l (concentration increased by 0.1 g / l every 1.5 minutes)
Nickel sulfate 25g / l
Pyrophosphate 300g / l
Tetraboric acid 6g / l
Ammonia water (surface smoothing agent) 3ml / l
Plating bath pH: 9 (adjusted with potassium hydroxide)
Plating bath temperature: 50 ° C
Anode: Nickel plate Plating current value: 1A
Plating time: 45 minutes (3) Copper plating Plating bath composition: Copper pyrophosphate 10 g / l
Pyrophosphate 300g / l
Tetraboric acid 6g / l
Ammonia water 3ml / l
Plating bath pH: 9
Plating bath temperature: 50 ° C
Anode: Copper plate Plating current value: 1A
Plating time: 15 minutes

(Production Example 2)
In Example 1, (1) nickel plating is not performed, and copper pyrophosphate is not added to the plating bath for the first 15 minutes in the copper-nickel treatment of (2), and then copper pyrophosphate is added every 1.5 minutes. A metal-coated carbon fiber fabric was produced in the same manner as in Example 1 except that 0.1 g / l was added.

  The obtained metal-coated carbon fiber had a metal layer having the same configuration as that of the metal-coated carbon fiber of Example 1.

(Production Example 3)
In Example 1, the nickel plating of (1) and the copper plating of (3) were not performed, and copper pyrophosphate was not added to the plating bath for the first 15 minutes in the copper-nickel treatment of (2). A metal-coated carbon fiber woven fabric was produced in the same manner as in Example 1 except that copper pyrophosphate was added at a rate of 0.1 g / l every 5 minutes.

  FIG. 4 is a graph showing changes in the composition of the metal layer in the metal-coated carbon fiber. In FIG. 4, the film thickness means the thickness of the metal layer that is laminated outwardly from the interface where the interface between the carbon fiber and the metal layer is “0”. FIG. 4 shows that the thickness of the nickel plating layer (first layer) is about 0.5 μm and the thickness of the copper-nickel alloy plating layer (second layer) is about 1.5 μm.

(Example 1)
70 metal-coated carbon fiber fabrics obtained in Production Example 1 were placed in a mold and used as a preform. The preform is preheated to 750 ° C., placed in a separate mold preheated to 750 ° C., molten aluminum alloy at 750 ° C. is supplied, and a pressure of 100 MPa is applied to the molten aluminum alloy into the preform. Impregnated. As an aluminum alloy, JIS
The chemical composition of H5202-1992 AC1A (the following composition) was used.
Cu: 4.0 to 5.0% by weight, Si: 1.2% by weight or less, Mg: 0.2% by weight or less, Zn: 0.3% by weight or less, Ni: 0.05% by weight or less, Ti: 0.25 wt% or less, Pb: 0.05 wt% or less, Sn: 0.05 wt% or less, Cr: 0.05 wt% or less, Al: remainder

  After the impregnation, the structure is naturally cooled, and the bonded body of the carbon fiber reinforced aluminum matrix composite material and the solidified body of the aluminum alloy is taken out of the mold, and the solidified body of the aluminum alloy is removed by cutting, thereby reinforcing the carbon fiber of the present invention. An aluminum matrix composite (size 20 cm × 30 cm × 1.6 cm) was obtained. This was a composite material composed of 40% by volume of metal-coated carbon fiber and 60% by volume of an aluminum alloy.

(Example 2)
The carbon fiber-reinforced aluminum-based composite of the present invention is the same as in Example 1 except that the metal-coated carbon fiber fabric obtained in Production Example 3 is used instead of the metal-coated carbon fiber fabric obtained in Production Example 1. The material was manufactured. The composite material was a composite material composed of 25% by volume of metal-coated carbon fibers and 75% by volume of an aluminum alloy.

(Test Example 1)
About the carbon fiber reinforced aluminum matrix composite of the present invention obtained in Example 1 and Example 2, the tensile strength was measured based on JIS H5202.

  For comparison, the same physical properties were measured for an aluminum alloy having a composition of AC1A. The results are shown in Table 1.

It is principal part sectional drawing which shows typically the structure of the carbon fiber reinforced aluminum matrix composite material which is the 1st Embodiment of this invention. It is principal part sectional drawing which shows typically the structure of the carbon fiber reinforced aluminum group composite material which is the 2nd Embodiment of this invention. It is a graph which shows the composition change of the metal layer in a metal covering carbon fiber. It is a graph which shows the composition change of the metal layer in a metal covering carbon fiber.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,10 Carbon fiber reinforced aluminum-based composite material 2 Base material 3,11 Metal-coated carbon fiber 4 Carbon fiber 5,12 Metal layer 6 First layer 7 Second layer 8 Third layer 9a, 9b, 9c, 9d, 9e Solid solution layer

Claims (8)

In a carbon fiber reinforced aluminum-based composite material reinforced by using aluminum or an aluminum alloy as a base material and mixing metal-coated carbon fibers in the base material,
Metal-coated carbon fiber is
A first layer comprising nickel or a nickel alloy formed in contact with the surface of the carbon fiber;
A metal layer containing nickel and copper formed in contact with the surface of the first layer, the second layer being a composition transition layer in which the composition ratio of nickel and copper changes continuously or stepwise A carbon fiber reinforced aluminum-based composite material, characterized in that it is a metal-coated carbon fiber having a coating layer comprising: Metal-coated carbon fiber is
A first layer comprising nickel or a nickel alloy formed in contact with the surface of the carbon fiber;
A second layer, which is a metal layer containing nickel and copper formed in contact with the surface of the first layer, and is a composition transition layer in which the composition ratio of nickel and copper changes continuously or stepwise;
A carbon-fiber-reinforced aluminum-based composite material, characterized in that it is a metal-coated carbon fiber having a coating layer comprising a third layer containing copper or a copper alloy formed in contact with the surface of the second layer. The composition ratio of nickel and copper in the second layer is
The carbon fiber reinforced aluminum-based composite material according to claim 1 or 2, wherein a transition is made so that the composition ratio of copper increases as the distance from the first layer increases in the layer thickness direction. The coating layer of metal-coated carbon fiber is
The carbon fiber reinforced aluminum matrix composite material according to any one of claims 1 to 3, wherein the carbon fiber reinforced aluminum matrix composite material is formed by plating. Metal-coated carbon fiber is
The carbon fiber reinforced aluminum-based composite material according to any one of claims 1 to 4, wherein after the coating layer is formed, heat treatment is performed at 500 ° C or higher and 1000 ° C or lower in a non-oxidizing atmosphere. Carbon fiber
One or more selected from PAN-based carbon fiber, pitch-based carbon fiber and vapor-grown carbon fiber,
The ratio (D / L) of fiber diameter D to fiber length L is 1/100000 or less, The carbon fiber-reinforced aluminum-based composite material according to any one of claims 1 to 5. Metal-coated carbon fiber
The carbon fiber-reinforced aluminum-based composite material according to any one of claims 1 to 6, wherein the carbon fiber-reinforced aluminum-based composite material is formed by charging into aluminum or an aluminum alloy in a molten state in a non-oxidizing atmosphere. The content of metal-coated carbon fiber is
The carbon fiber reinforced aluminum matrix composite material according to any one of claims 1 to 7, wherein the carbon fiber reinforced aluminum matrix composite material is 5% or more and 70% or less by volume%.

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