JP2019026884A - Metal-carbon particle composite - Google Patents

Abstract

To provide a metal-carbon particle composite having high thermal conductivity and high moldability.SOLUTION: A metal-carbon particle composite 20 is obtained by joining and integrating a metal layer 22 made of a metal matrix 23 and a flaky graphite particle dispersion layer 21 in which flaky graphite particles 1 are dispersed in the metal matrix 23 are laminated in a plurality of layers alternately in a thickness direction B of the composite material 20. An average thickness of the metal layer 22 is in the range of 12 to 100 μm. An average thickness of the flaky graphite particle dispersion layer 21 is in the range of 1 to 100 μm. When a ratio of the average thickness of the metal layer 22 and an average thickness of the flaky graphite particle dispersion layer 21 is set to 1: X, X is in the range of 0.1 to 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a metal-carbon particle composite material in which scaly graphite particles as carbon particles are dispersed in a metal matrix.

  In the present specification and claims, the term “aluminum” is used to include both pure aluminum and aluminum alloys, and the term “copper” refers to pure copper and copper unless otherwise indicated in the text. Used to include both copper alloys.

  Further, in this specification, for convenience of explanation, a direction in which a plurality of metal layers and scaly graphite particle dispersion layers are alternately laminated in the metal-carbon particle composite material is defined as a thickness direction of the composite material, and the composite material The plane perpendicular to the thickness direction and the direction thereof are defined as the plane and the plane direction of the composite material, respectively.

  Metal-carbon particle composite materials generally have high thermal conductivity and low linear expansion. The following documents disclose this type of composite material and its manufacturing method.

  Japanese Patent No. 5150905 (Patent Document 1) forms a preform in which a film containing a carbon fiber is formed on a sheet-like or foil-like metal support, and a plurality of these are stacked to form a laminate. A method for producing a metal-based carbon fiber composite material as a metal-carbon particle composite material by heat-welding the body is disclosed. In this method, in the obtained composite material, the thermal conductivity is increased only in one direction in which the carbon fibers are oriented.

  Japanese Patent Laying-Open No. 2015-25158 (Patent Document 2) discloses a method in which a plurality of metal layers and carbon fiber layers are alternately stacked in such a manner that metal layers are arranged on both outermost sides in the stacking direction. Discloses a composite material of metal and carbon fiber, which is bonded and integrated by diffusion bonding.

  In this composite material, the metal layers disposed on both outermost sides in the thickness direction of the composite material (referred to as “outermost metal layers” for convenience of explanation) are disposed inside both outermost metal layers of the composite material. It is thicker than the formed metal layer (this is referred to as “inner metal layer” for convenience of explanation). The reason is that the outermost metal layer mainly protects the outer surface of the composite material in order to prevent the carbon fibers in the composite material from being exposed to the outer surface of the composite material and falling off from the outer surface of the composite material. This is because it has a role as a protective layer.

  Japanese Patent No. 4441768 (Patent Document 3) discloses a metal-carbon by forming a sintering precursor using a mixture of scaly graphite powder and a predetermined scaly metal powder and sintering the sintering precursor. A method for producing a particle composite is disclosed. This method has problems that it is difficult to handle the metal powder at the time of manufacture and that the manufacturing cost is high.

  JP 2006-1232 A (Patent Publication 4) discloses a metal-carbon particle composite material by hot-press sintering a composite in which a plurality of crystalline carbon material layers and metal layers are alternately stacked. Discloses a method for producing a high thermal conductivity and low thermal expansion composite. In this method, it is difficult to sinter the composite, and therefore, it is considered that the joining is insufficient and the joining interface tends to shift.

  As another document disclosing the metal-carbon particle composite material, there is JP-A-2015-217655 (Patent Document 5).

Patent No. 5150905 Japanese Patent Laying-Open No. 2015-25158 Japanese Patent No. 4441768 JP 2006-1232 A JP2015-217655A

  Thus, the next generation semiconductor chip using SiC or the like can operate at a high temperature. It is desirable that the material of the constituent layer of the cooler that cools such a chip has higher thermal conductivity (high thermal conductivity) in order to enhance the cooling performance of the cooler. Therefore, it is conceivable to use a metal-carbon particle composite material as this material.

  However, when carbon fiber is used as the carbon particle of the metal-carbon particle composite material, the composite material has high moldability, but the carbon fiber is oriented because the thermal conductivity is increased in the composite material. Therefore, it is not easy to manufacture a composite material having a high thermal conductivity.

  When scaly graphite particles are used as the carbon particles of the metal-carbon particle composite material, it is possible to produce a composite material having high thermal conductivity, but there is a drawback that the moldability of the composite material is not so good. It was. For this reason, when the composite material is bent, for example, the layers constituting the composite material (that is, the metal layer and the scaly graphite particle layer) are easily peeled off or the composite material is easily broken.

  This invention is made | formed in view of the technical background mentioned above, The objective is to provide the metal-carbon particle composite material which has high heat conductivity and high moldability.

  The present invention provides the following means.

[1] A metal layer composed of a metal matrix and a scaly graphite particle dispersion layer in which scaly graphite particles are dispersed in the metal matrix are joined and integrated in a state where a plurality of layers are alternately laminated,
The average thickness of the metal layer is in the range of 12-100 μm;
The average thickness of the scaly graphite particle dispersion layer is in the range of 1 to 100 μm,
A metal-carbon particle composite material in which X is in the range of 0.1 to 1, where the ratio of the average thickness of the metal layer to the average thickness of the scaly graphite particle dispersion layer is 1: X.

  [2] The metal-carbon particle composite material according to [1], wherein the metal matrix is aluminum or copper.

  The present invention has the following effects.

  In the metal-carbon particle composite material according to item 1, the scaly graphite particles are used as the carbon particles, whereby a composite material having a high thermal conductivity can be easily produced.

  Further, the average thickness of the metal layer is in the range of 12 to 100 μm, the average thickness of the flaky graphite particle dispersion layer is in the range of 1 to 100 μm, the average thickness of the metal layer and the average thickness of the flaky graphite particle layer When the ratio is 1: X, since X is in the range of 0.1 to 1, the metal layer is thick, thereby improving the moldability of the composite material.

  In the preceding item 2, when the metal matrix is aluminum or copper, the thermal conductivity of the composite material can be reliably increased.

FIG. 1 is a schematic cross-sectional structure diagram of a metal-carbon particle composite material according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional structure diagram for explaining a method for calculating the average thickness of the metal layer and the average thickness of the scaly graphite particle layer. FIG. 3 is a flowchart of the manufacturing method of the composite material. FIG. 4 is a schematic diagram illustrating a process of obtaining a coated foil. FIG. 5 is a schematic view when the strip of the coated foil is cut. FIG. 6 is a schematic front view of the laminate. FIG. 7 is a schematic view when the laminate is sintered by a pressure heating sintering apparatus.

  Next, an embodiment of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, a metal-carbon particle composite material 20 according to an embodiment of the present invention includes a plurality of metal layers (regions surrounded by an alternate long and short dash line) 22 composed of a metal matrix (shown by dot shading) 23. And a plurality of scaly graphite particle dispersion layers (regions surrounded by a two-dot chain line) 21 in which scaly graphite particles 1 as carbon particles are dispersed in a metal matrix 23. The metal layers 22 and the scaly graphite particle dispersion layers 21 are arranged in a state where a plurality of layers are alternately stacked in the thickness direction B of the composite material 20 over substantially the entire thickness direction B of the composite material 20. In this state, the plurality of metal layers 22 and the plurality of scaly graphite particle dispersion layers 21 are joined and integrated (specifically, sintered and integrated in detail), whereby the composite material 20 is formed.

  In the composite material 20, since the scaly graphite particles 1 are used as the carbon particles, the composite material 20 is a metal-flaky graphite particle composite material in detail.

  In each of the scaly graphite particle dispersion layers 21, a large number of scaly graphite particles 1 are dispersed in the planar direction A of the composite material 20 in the metal matrix 23.

  It is desirable that the scaly graphite particles 1 have a heat conductivity as high as possible (eg, highly heat-conducting scaly graphite particles).

  The particle size of the flaky graphite particles 1 is not limited, but is dispersed in the metal matrix 23 when the length of the flaky graphite particles 1 in the longest axial direction is the particle size of the flaky graphite particles 1. The average length in the longest axial direction of many scaly graphite particles 1 is desirably 300 μm or more. In this case, the interfacial thermal resistance between the scaly graphite particles 1 and the metal matrix 23 can be reduced inside the composite material 20, whereby the thermal conductivity of the composite material 20 can be reliably increased. The upper limit of the average length of the scaly graphite particles 1 in the longest axial direction is not limited, and is usually 1000 μm.

  Here, the average length of the scaly graphite particles 1 in the longest axial direction is calculated by the following method.

  One hundred scaly graphite particles arbitrarily selected from a number of scaly graphite particles dispersed on a glass plate are observed with an optical microscope, and the length of each scaly graphite particle is measured in the longest direction. And let those arithmetic mean values be the average length of the longest axial direction of scaly graphite particles.

  The aspect ratio of the scaly graphite particles 1 is not limited, and the average aspect ratio is particularly preferably 30 or more. The desirable upper limit of the average aspect ratio of the scaly graphite particles 1 is not limited and is usually 100.

  The type of the metal matrix 23 is not limited, but in particular, the metal matrix 23 is preferably aluminum or copper. In this case, the thermal conductivity of the composite material 20 can be reliably increased.

  In the composite material 20 of this embodiment, the scale-like graphite particles 1 are used as the carbon particles, so that the composite material 20 having high thermal conductivity can be easily manufactured.

  In the composite material 20 of the present embodiment, the average thickness of the metal layer 22 and the average thickness of the scaly graphite particle dispersion layer 21 are defined by the following method.

  As shown in FIG. 2, a field of view of 1.5 mm (planar direction A of the composite material 20) × 1.0 mm (thickness direction B of the composite material 20) of a cross section of the composite material 20 cut in the thickness direction B In the cross-sectional structure photograph obtained by photographing 10 grid lines 60 extending in the thickness direction B of the composite material 20 in the plane direction A of the composite material 20 at intervals of 0.1 mm, one grid line 60 is one. The length t of the line segment traversing the scaly graphite particles 1 is measured as the thickness of one scaly graphite particle dispersion layer 21, and all of the scaly graphite particle dispersion layers 21 measured for 10 grid lines 60 are measured. The arithmetic average value of the thickness is defined as the average thickness of the scaly graphite particle dispersion layer 21, and one grid line 60 is one metal matrix portion (that is, two adjacent ones crossing the one grid line 60 are adjacent to each other). Scaly graphite grains The length T of the line crossing the portion between 1 and 1 is measured as the thickness of one metal layer 22, and the arithmetic average value of the thicknesses of all the metal layers 22 measured for 10 grid lines 60. Is defined as the average thickness of the metal layer 22.

  However, the metal layers disposed on both outermost sides in the thickness direction B of the composite material 20, that is, the outermost metal layers, are excluded from the metal layers applied to the calculation of the average thickness of the metal layer 22. The reason is that the outermost metal layer generally serves as a protective layer that protects the outer surface of the composite material 20, so that the metal layers generally disposed inside both outermost metal layers of the composite material 20 (ie, This is because it is often thicker than the inner metal layer 22.

  In the composite material 20 of this embodiment, the average thickness of the metal layer 22 is set in the range of 12 to 100 μm, and the average thickness of the scaly graphite particle dispersion layer 21 is set in the range of 1 to 100 μm. When the ratio of the average thickness of the metal layer 22 and the average thickness of the scaly graphite particle dispersion layer 21 is 1: X, X is set in the range of 0.1-1.

  By setting the average thickness of the metal layer 22, the average thickness of the scaly graphite particle-dispersed layer 21, and X in the ranges described above, the thermal conductivity of the composite material 20 can be increased, and the composite material 20 can be increased. Can be improved (eg, bending workability, ductility, punching workability).

  When X is less than 0.1, the content of the scaly graphite particles 1 in the composite material 20 is too small, and therefore the effect of increasing the thermal conductivity of the composite material 20 is inferior. When X exceeds 1, the content of the scaly graphite particles 1 in the composite material 20 is too large, which makes it difficult to produce the composite material 20 and deteriorates the moldability of the composite material 20.

  The particularly desirable thickness of the metal layer 22 is in the range of 15 to 50 μm, and the particularly desirable thickness of the scaly graphite particle dispersion layer 21 is in the range of 10 to 35 μm. X is particularly preferably in the range of 0.2 to 0.7.

  In addition, the volume content of the scaly graphite particles 1 in the composite material 20 is desirably in the range of 10 to 50% by volume with respect to the volume of the composite material 20. In this case, the moldability of the composite material 20 can be reliably improved.

  Although the manufacturing method of the composite material 20 is not limited, the desirable manufacturing method is demonstrated below with reference to FIGS.

  As shown in FIG. 3, the manufacturing method of the composite material 20 includes a step S1 of obtaining a coating foil, a step S2 of forming a laminate, and a step S3 of sintering the laminate. It is done in order.

  In step S1 of obtaining the coating foil, as shown in FIG. 4, the coating liquid 5 containing the scaly graphite particles 1, the binder 2, and the binder 2 solvent 3 in a mixed state is applied to the surface 10a of the metal foil 10 to be coated. By applying the coating foil 12, the coating foil 12 having the scaly graphite particle layer 11 formed on the surface 10 a to be coated of the metal foil 10 is obtained.

  In the present embodiment, a strip-shaped strip 10 </ b> A of the metal foil 10 (that is, a strip-shaped long metal foil 10) is used as the metal foil 10.

  The planned coating surface 10a of the strip 10A of the metal foil 10 is at least one surface of both surfaces in the thickness direction of the strip 10A of the metal foil 10, and in the present embodiment, the planned coating surface 10a is the metal foil. It is only the surface on one side in the thickness direction of 10 strips 10A.

  The metal material of the metal foil 10 is determined according to the desired type of the metal matrix 23 of the composite material 20. That is, when the metal matrix 23 is an aluminum matrix, an aluminum foil is used as the metal foil 10, and when the metal matrix 23 is a copper matrix, a copper foil is used as the metal foil 10.

  When the metal foil 10 is an aluminum foil, the material of the aluminum foil is not limited, and is, for example, pure aluminum or aluminum alloy having a purity of 99% or more.

  When the metal foil 10 is a copper foil, the material of the copper foil is not limited and is, for example, pure copper or a copper alloy.

  The thickness of the metal foil 10 may be a thickness such that the average thickness of the metal layer 22 of the composite material 20 obtained is in the range of 12 to 100 μm. Here, when the thickness of the metal foil 10 is 10 μm or less, since the material cost of the metal foil 10 is high and the handling property of the metal foil 10 is poor, it is desirable that the thickness of the metal foil 10 exceeds 10 μm. .

  The binder 2 gives the scaly graphite particles 1 adhesion to the surface 10a to which the strip 10A of the metal foil 10 is to be applied, thereby preventing the scaly graphite particles 1 from accidentally falling off the surface 10a to be applied. Is to do. The binder 2 is usually made of a resin such as an organic resin. As the binder 2, polyethylene oxide, polyvinyl alcohol, acrylic resin, or the like is used.

  The solvent 3 dissolves the binder 2. As the solvent 3, a hydrophilic solvent (isopropyl alcohol, water), an organic solvent, or the like is used.

  The coating liquid 5 is obtained as follows, for example.

  That is, the coating liquid 5 is obtained by putting the flaky graphite particles 1, the binder 2, and the solvent 3 in the mixing container 41 and mixing them with the stirring mixer 42. If necessary, a dispersant (not shown), a surface conditioner (not shown) and the like are added to the coating liquid 5. As the stirring mixer 42, a disper, a planetary mixer, a bead mill, or the like is used.

  A method and a coating apparatus for coating the coating liquid 5 on the coating scheduled surface 10a of the strip 10A of the metal foil 10 are not limited. For example, a gravure coater, a three roll coater (offset type), a knife coater, a die coater, a roll coater (two rolls), a spray coater, a curtain coater, a reverse roll coater or the like is used as a coating apparatus for the coating liquid 5. It is done.

  In the present embodiment, as shown in FIG. 4, the coating of the coating liquid 5 is performed by unwinding roll 37 a for unwinding the strip material 10 </ b> A of the metal foil 10 and the strip material 10 </ b> A of the metal foil 10 (the strip of the coating foil 12. It is carried out by a roll-to-roll type coating apparatus using a winding roll 37b for winding the material 12A). The coating method of the coating liquid 5 in this case is as follows.

  Between the unwinding roll 37a and the winding roll 37b, the coating apparatus 30 and the drying furnace 38 are installed side by side in the feed direction F of the strip 10A of the metal foil 10.

  The coating apparatus 30 is, for example, a gravure coater (direct gravure coater in detail), a gravure roll 31, a backup roll 33, a coating liquid adhering means 35 for adhering the coating liquid 5 to the peripheral surface 31 a of the gravure roll 31, a doctor. A blade 34 and the like are provided.

  A large number of cells (not shown) are arranged on the peripheral surface 31a of the gravure roll 31 in an orderly manner. The cell is a lattice cell, a pyramid cell, a turtle shell cell, a circular cell, a diagonal cell, or the like.

  The coating liquid adhering means 35 includes a coating liquid pan (not shown) containing the coating liquid 5, and a part of the circumferential surface 31a of the gravure roll 31 in the circumferential direction is coated in the pan. The gravure roll 31 rotates around its central axis in contact with the liquid 5, so that the coating liquid 5 is attached to the peripheral surface 31 a of the gravure roll 31 in the circumferential direction.

  The strip 10A of the metal foil 10 unwound from the unwinding roll 37a passes between the gravure roll 31 and the backup roll 33 of the gravure coater (coating apparatus 30). At this time, the coating liquid 5 is applied to the planned coating surface 10a of the strip 10A of the metal foil 10 by the gravure roll 31 in the length direction of the strip 10A of the metal foil 10 (that is, the feed direction F of the strip 10A of the metal foil 10). ) Is continuously applied in layers. As a result, the strip 12A of the coating foil 12 in which the scaly graphite particle layer 11 made of the coating solution 5 is formed (coated) on the planned coating surface 10a of the strip 10A of the metal foil 10 is obtained.

  Then, when the strip 12 </ b> A of the coating foil 12 passes through the drying furnace 38, the solvent 3 in the scaly graphite particle layer 11 is removed by evaporation from the scaly graphite particle layer 11. Thereafter, the strip 12A of the coating foil 12 is wound around the winding roll 37b.

The coating amount of the coating solution 5 on the planned coating surface 10a of the strip 10A of the metal foil 10 is not limited. In particular, the coating liquid 5 is a surface to be coated such that the coating amount of the scaly graphite particles 1 in the scaly graphite particle layer 11 is 10 to 160 g / m ² (preferably 25 to 80 g / m ² ). It is desirable to apply to 10a.

  The step S2 of forming the laminate is a step of forming the laminate 15 in a state where a plurality of coating foils 12 are laminated, and is performed as follows, for example.

  As shown in FIG. 5, first, the strip material 12 </ b> A of the coating foil 12 unwound from the winding roll 37 b is cut into a predetermined shape by the cutting machine 45. Thereby, a plurality of coating foils 12 having a predetermined shape (eg, substantially rectangular shape) are cut out from the strip 12A of the coating foil 12. That is, each coating foil 12 is made of a cut piece obtained by cutting the strip 12A of the coating foil 12.

  Next, a plurality of coating foils 12 are laminated as shown in FIG. Thereby, the laminated body 15 in a state where a plurality of coating foils 12 are laminated is formed.

  When laminating the coating foil 12, it is desirable not to interpose metal particles as a sintering aid between the overlapping coating foils 12, 12. In this case, the stacked body 15 can be easily formed. As the metal particles, the same kind of metal powder as the metal foil 10 is used. However, in this embodiment, it is not limited to not interposing a metal particle between the coating foils 12 and 12 which overlap mutually, You may interpose a metal particle.

  The number of coating foils 12 for forming the laminate 15 is not limited, and is set according to the desired thickness of the composite material 20, for example, 10 to 1000.

  Here, as in the composite material described in JP-A-2015-25158 (Patent Document 2), a composite material in which a metal layer as a protective layer is disposed on the outermost side in the thickness direction is manufactured. As described in the publication, when a plurality of coating foils 12 are laminated, a protective layer metal foil (the metal foil is a scaly graphite particle layer or the like) is formed on the outermost side in the thickness direction of the laminate 15. A carbon particle layer is not laminated). The protective layer protects the outer surface of the composite material 20 in order to prevent the scaly graphite particles 1 in the composite material 20 from being exposed to the outer surface of the composite material 20 or falling off from the outer surface of the composite material 20. The thickness of the coating foil 12 is usually larger than that of the metal foil 10 of the coating foil 12.

  In the step S3 of sintering the laminated body 15, the laminated body 15 is sintered by heating while being uniaxially pressed in a predetermined sintering atmosphere (for example, non-oxidizing atmosphere), whereby a plurality of coating foils 12 are obtained. Are integrated together (specifically, sintered integrated).

  The sintering method of the laminated body 15 is selected from a vacuum hot press method, a discharge plasma sintering method (SPS method), a hot isostatic pressing method (HIP method), a rolling method, and the like.

  Specifically, as shown in FIG. 7, for example, the laminated body 15 is disposed in the sintering chamber 51 of the pressure heating and sintering apparatus 50, and the laminated body 15 is thickened in a predetermined sintering atmosphere. The laminated body 15 is sintered by heating in a predetermined sintering condition while pressing in the vertical direction (that is, the laminating direction of the coating foil 12). Thereby, the metal-carbon particle composite material 20 having the cross-sectional structure shown in FIG. 1 is obtained.

  The sintering apparatus 50 can press the laminated body 15 uniaxially, and includes, for example, a pair of pressing punches 52 and 52 as the means. Both pressing punches 52, 52 are arranged to face each other.

  The pressurization to the laminated body 15 is performed by pressing the laminated body 15 between the pressing punches 52 and 52 in the thickness direction. Therefore, the pressing direction of the laminate 15 is the thickness direction of the laminate 15, and this direction coincides with the thickness direction (B, see FIG. 1) of the composite material 20. That is, the thickness direction B of the composite material 20 matches the pressing direction of the laminate 15.

  The heating temperature of the laminated body 15 for sintering the laminated body 15, that is, the sintering temperature of the laminated body 15 is not limited, and is usually equal to or lower than the melting point of the metal material of the metal foil 10. And a temperature between about 50 ° C. lower than the melting point. Specifically, when the metal foil 10 is, for example, an aluminum foil, the sintering temperature of the laminate 15 is set to, for example, 550 to 620 ° C.

  The binder 2 present in the laminate 15 disappears due to sublimation, dispersion, or the like while the laminate 15 is heated so that the temperature of the laminate 15 rises from about room temperature to the sintering temperature of the laminate 15 in this step S3. And removed from the laminate 15.

  In this step S3, the laminate 15 is heated under pressure as described above, so that a part of the metal material of the metal foil 10 penetrates into the flaky graphite particle layer 11 and into the flaky graphite particle layer 11. It fills in the existing fine voids (for example, the gaps between the flake graphite particles in the flake graphite particle layer 11), and the voids substantially disappear. Thereby, the density of the composite material 20 is increased and the strength of the composite material 20 is improved. Furthermore, the scaly graphite particles 1 are oriented in the planar direction A of the composite material 20.

  Further, when a part of the metal material of the metal foil 10 penetrates into the scaly graphite particle layer 11, the scaly graphite particles 1 in each scaly graphite particle layer 11 are composited in the metal matrix 23 of the composite material 20. In other words, each scale-like graphite particle layer 11 becomes a scale-like graphite particle dispersion layer 21 of the composite material 20 as shown in FIG. Each metal foil 10 becomes a metal layer 22 of the composite material 20.

  Accordingly, in the composite material 20, the scaly graphite particle dispersion layer 21 and the metal layer 22 are alternately provided in the thickness direction B of the composite material 20 over substantially the entire thickness direction of the composite material 20 as described above. Arrange in a stacked state.

  Since the composite material 20 of the present embodiment has a high thermal conductivity as described above, it can be suitably used as a material for a constituent layer of a power module cooler, and a lithium ion secondary battery (LiB). The battery can be suitably used as a material for battery constituent members. The power module is used for a vehicle such as a hybrid car (HEV), an electric vehicle (EV), or a train, or used in an energy field such as wind power generation or solar power generation.

  When the composite material 20 is used as a material of a constituent layer of a power module cooler, the composite material 20 includes a wiring layer, a buffer layer, a heat dissipation layer (eg, a heat sink) among a plurality of layers constituting the cooler. It is particularly preferably used for materials.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention.

  Next, specific examples and comparative examples of the present invention are shown below. However, the present invention is not limited to the following examples.

<Example 1>
In Example 1, a metal-carbon particle composite material was produced by the following procedure.

  In a mixing container, scaly graphite particles as carbon particles, a 3% by weight aqueous solution of polyethylene oxide as a binder and a 10% by weight aqueous solution of polyvinyl alcohol, isopropyl alcohol and water as a solvent, a dispersant and a surface conditioner are mixed. These were stirred and mixed with a disper to obtain a coating solution. The viscosity of the coating solution was 1000 mPa · s at 25 ° C.

  The average length of the scaly graphite particles in the longest axial direction was 300 μm, and the average aspect ratio of the scaly graphite particles was 30. The content of the scaly graphite particles contained in the coating liquid was 90% by mass with respect to the total mass of the binder and the scaly graphite particles.

  A coating solution is applied in a layer form at a coating speed of 2 m / min using a roll-to-roll gravure coater (specifically, a direct gravure coater) on the planned coating surface of a strip of aluminum foil (Al foil). As a result, a strip of coated foil was obtained in which a scaly graphite particle layer was formed on the planned coating surface of the strip of aluminum foil.

  The material of the strip of aluminum foil was JIS (Japanese Industrial Standard) aluminum alloy number 1N30 (hereinafter simply referred to as “A1N30”), and its thickness was 50 μm and its width was 300 mm. The planned coating surface of the aluminum foil strip was the surface on one side in the thickness direction of the aluminum foil strip.

And the solvent in scaly graphite particle layer was evaporated and removed from the scaly graphite particle layer by letting the strip of coating foil pass in a drying furnace. The coating amount of the scaly graphite particles in the scaly graphite particle layer was 80 g / m ² .

  Subsequently, the strip of the coating foil was cut into a square shape (size: width 50 mm × length 50 mm), whereby a plurality of square coating foils were cut out from the coating foil strip. And the laminated body was formed by laminating | stacking 12 coating foil.

  Next, predetermined sintering conditions are performed while the laminate is pressed in the thickness direction (that is, the coating foil laminating direction) in a vacuum atmosphere by a discharge plasma sintering apparatus (SPS apparatus) as a pressure heating sintering apparatus. The laminate was sintered by heating at This obtained the aluminum-flaky graphite particle composite material as a metal-carbon particle composite material. The thickness of the composite material was 1 mm. Moreover, the volume content of the scaly graphite particles in the composite material was 40% by volume with respect to the volume of the composite material.

  The sintering conditions applied to this sintering were as follows.

  The sintering temperature was 620 ° C., the holding time of the sintering temperature (ie, sintering time) was 3 hours, the rate of temperature increase from room temperature was 20 ° C./min, the pressure applied to the laminate was 20 MPa, and the degree of vacuum was 3 Pa. It was. In addition, the binder was removed from the laminate by temporarily stopping the temperature rise while heating the laminate from room temperature to a sintering temperature of 620 ° C. The binder removal conditions applied at this time were as follows.

  The heating temperature of the laminate for removing the binder was 450 ° C., and the holding time was 30 min.

  In the composite material, aluminum as a metal matrix sufficiently permeates between the scaly graphite particles, and there are almost no voids inside the composite material, and the density of the composite material is 99% of the theoretical density of the composite material. The sintered state of the composite material was good.

  Moreover, the thermal conductivity in the plane direction of the composite material was 442 W / (m · K), which was higher than the thermal conductivity of aluminum.

  Also, a field of view of 1.5 mm (in the plane direction of the composite material) × 1.0 mm (in the thickness direction of the composite material) is photographed with an optical microscope (magnification: 75 times) for a cross section of the composite material cut in the thickness direction. The average thickness of the aluminum layer and the average thickness of the scaly graphite particle dispersion layer were calculated according to the definitions described in the above-described embodiments, using the obtained cross-sectional structure photographs. As a result, the average thickness of the aluminum layer was 52 μm, and the average thickness of the scaly graphite particle dispersed layer was 33 μm. Therefore, X was 0.63.

  Further, a 50 mm × 10 mm bending test piece (thickness 1 mm) was cut out from the composite material, and the test piece was subjected to 90 ° bending with a bending radius of 3 mm. As a result, the aluminum layer and scaly graphite particle dispersion layer of the test piece were obtained. No systematic peeling or breaking was observed.

<Example 2>
The same coating solution as that used in Example 1 was prepared. Moreover, the strip of aluminum foil of the following structure was prepared as a strip of metal foil.

  The material of the strip of aluminum foil was A1N30, the thickness was 15 μm, and the width was 300 mm. The planned coating surface of the aluminum foil strip was the surface on one side in the thickness direction of the aluminum foil strip.

  Next, the coating liquid is applied to the surface of the aluminum foil strip scheduled to be coated by the same coating method as in Example 1, whereby a scaly graphite particle layer is formed on the surface of the aluminum foil strip planned to be coated. A strip of coated foil was obtained.

And the solvent in scaly graphite particle layer was evaporated and removed from the scaly graphite particle layer by letting the strip of coating foil pass in a drying furnace. The coating amount of the scaly graphite particles in the scaly graphite particle layer was 25 g / m ² .

  Next, a plurality of coating foils having the same size and shape as in Example 1 were cut out from the strip of coating foil. And the laminated body was formed by laminating | stacking 40 coating foil.

  Next, the laminate was sintered with the same sintering apparatus and sintering conditions as in Example 1, thereby obtaining an aluminum-flaky graphite particle composite material. The thickness of the composite material was 1 mm. Moreover, the volume content of the scaly graphite particles in the composite material was 40% by volume with respect to the volume of the composite material.

  In the composite material, aluminum as a metal matrix sufficiently permeates between the scaly graphite particles, and there are almost no voids inside the composite material, and the density of the composite material is 99% of the theoretical density of the composite material. The sintered state of the composite material was good.

  Further, the thermal conductivity in the planar direction of the composite material was 436 W / (m · K), which was higher than the thermal conductivity of aluminum.

  Moreover, when the average thickness of the aluminum layer of the composite material and the average thickness of the flaky graphite particle dispersion layer were calculated by the same method as in Example 1, the average thickness of the aluminum layer was 16 μm, and the flaky graphite particle dispersion layer The average thickness was 10 μm. Therefore, X was 0.63.

  Further, a bending test piece having the same dimensions and shape as in Example 1 was cut out from the composite material, and the test piece was bent under the same bending conditions as in Example 1. As a result, the aluminum layer and scaly graphite particles of the test piece were obtained. There was no systematic peeling or breakage of the dispersed layer.

<Example 3>
The same coating solution as that used in Example 1 was prepared. Moreover, the strip of aluminum foil of the following structure was prepared as a strip of metal foil.

  The material of the strip of aluminum foil was A1N30, the thickness was 20 μm, and the width was 300 mm. The planned coating surface of the aluminum foil strip was the surface on one side in the thickness direction of the aluminum foil strip.

  Next, the coating liquid is applied to the surface of the aluminum foil strip scheduled to be coated by the same coating method as in Example 1, whereby a scaly graphite particle layer is formed on the surface of the aluminum foil strip planned to be coated. A strip of coated foil was obtained.

And the solvent in scaly graphite particle layer was evaporated and removed from the scaly graphite particle layer by letting the strip of coating foil pass in a drying furnace. The coating amount of the scaly graphite particles in the scaly graphite particle layer was 10 g / m ² .

  Next, a plurality of coating foils having the same size and shape as in Example 1 were cut out from the strip of coating foil. And the laminated body was formed by laminating | stacking 40 coating foil.

  Next, the laminate was sintered with the same sintering apparatus and sintering conditions as in Example 1, thereby obtaining an aluminum-flaky graphite particle composite material. The thickness of the composite material was 1 mm. Moreover, the volume content of the scaly graphite particles in the composite material was 17% by volume with respect to the volume of the composite material.

  In the composite material, aluminum as a metal matrix sufficiently permeates between the scaly graphite particles, and there are almost no voids inside the composite material, and the density of the composite material is 99% of the theoretical density of the composite material. The sintered state of the composite material was good.

  Moreover, the thermal conductivity in the planar direction of the composite material was 320 W / (m · K), which was higher than the thermal conductivity of aluminum.

  Further, when the average thickness of the aluminum layer of the composite material and the average thickness of the scaly graphite particle dispersion layer were calculated in the same manner as in Example 1, the average thickness of the aluminum layer was 21 μm, and the scaly graphite particle dispersion layer The average thickness was 4 μm. Therefore, X was 0.16.

  Further, a bending test piece having the same dimensions and shape as in Example 1 was cut out from the composite material, and the test piece was bent under the same bending conditions as in Example 1. As a result, the aluminum layer and scaly graphite particles of the test piece were obtained. There was no systematic peeling or breakage of the dispersed layer.

<Example 4>
The same coating solution as that used in Example 1 was prepared. Moreover, the strip of aluminum foil of the following structure was prepared as a strip of metal foil.

  The material of the strip of aluminum foil was A1N30, the thickness was 15 μm, and the width was 300 mm. The planned coating surface of the aluminum foil strip was the surface on one side in the thickness direction of the aluminum foil strip.

  Next, the coating liquid is applied to the surface of the aluminum foil strip scheduled to be coated by the same coating method as in Example 1, whereby a scaly graphite particle layer is formed on the surface of the aluminum foil strip planned to be coated. A strip of coated foil was obtained.

And the solvent in scaly graphite particle layer was evaporated and removed from the scaly graphite particle layer by letting the strip of coating foil pass in a drying furnace. The coating amount of the scaly graphite particles in the scaly graphite particle layer was 36 g / m ² .

  Next, a plurality of coating foils having the same size and shape as in Example 1 were cut out from the strip of coating foil. And the laminated body was formed by laminating | stacking 33 coating foil.

  Next, the laminate was sintered with the same sintering apparatus and sintering conditions as in Example 1, thereby obtaining an aluminum-flaky graphite particle composite material. The thickness of the composite material was 1 mm. Moreover, the volume content of the scaly graphite particles in the composite material was 50% by volume with respect to the volume of the composite material.

  In the composite material, aluminum as a metal matrix sufficiently permeates between the scaly graphite particles, and there are almost no voids inside the composite material, and the density of the composite material is 99% of the theoretical density of the composite material. The sintered state of the composite material was good.

  Further, the thermal conductivity in the planar direction of the composite material was 522 W / (m · K), which was higher than the thermal conductivity of aluminum.

  Moreover, when the average thickness of the aluminum layer of the composite material and the average thickness of the flaky graphite particle dispersion layer were calculated by the same method as in Example 1, the average thickness of the aluminum layer was 16 μm, and the flaky graphite particle dispersion layer The average thickness was 15 μm. Therefore, X was 0.94.

  Further, a bending test piece having the same dimensions and shape as in Example 1 was cut out from the composite material, and the test piece was bent under the same bending conditions as in Example 1. As a result, the aluminum layer and scaly graphite particles of the test piece were obtained. There was no systematic peeling or breakage of the dispersed layer.

<Example 5>
The same coating solution as that used in Example 1 was prepared. In addition, a strip of copper foil (Cu foil) having the following configuration was prepared as a strip of metal foil.

  The material of the strip of copper foil was C1020, its thickness was 50 μm and its width was 300 mm. The planned coating surface of the copper foil strip was the surface on one side in the thickness direction of the copper foil strip.

  Next, the coating liquid is applied to the surface where the copper foil strip is to be coated by the same coating method as in Example 1, whereby a scaly graphite particle layer is formed on the surface where the copper foil strip is to be coated. A strip of coated foil was obtained.

And the solvent in scaly graphite particle layer was evaporated and removed from the scaly graphite particle layer by letting the strip of coating foil pass in a drying furnace. The coating amount of the scaly graphite particles in the scaly graphite particle layer was 80 g / m ² .

  Next, a plurality of coating foils having the same size and shape as in Example 1 were cut out from the strip of coating foil. And the laminated body was formed by laminating | stacking 12 coating foil.

  Next, the laminate was sintered by heating it under a predetermined sintering condition while pressing the laminate in the thickness direction in a vacuum atmosphere by a discharge plasma sintering apparatus. This obtained the copper-flaky graphite particle composite material as a metal-carbon particle composite material. The thickness of the composite material was 1 mm. Moreover, the volume content of the scaly graphite particles in the composite material was 40% by volume with respect to the volume of the composite material.

  In the composite material, copper as a metal matrix sufficiently permeates between the scaly graphite particles, and there are almost no voids inside the composite material, and the density of the composite material is 99% of the theoretical density of the composite material. The sintered state of the composite material was good.

  Further, the thermal conductivity in the plane direction of the composite material was 530 W / (m · K), which was higher than the thermal conductivity of copper.

  Moreover, when the average thickness of the copper layer of the composite material and the average thickness of the flaky graphite particle dispersion layer were calculated in the same manner as in Example 1, the average thickness of the copper layer was 53 μm, and the flaky graphite particle dispersion layer The average thickness was 33 μm. Therefore, X was 0.62.

  Further, a bending test piece having the same dimensions and shape as in Example 1 was cut out from the composite material, and the test piece was bent under the same bending conditions as in Example 1. As a result, the copper layer and scaly graphite particles of the test piece were obtained. There was no systematic peeling or breakage of the dispersed layer.

<Comparative Example 1>
The same coating solution as that used in Example 1 was prepared. Moreover, the strip of aluminum foil of the following structure was prepared as a strip of metal foil.

  The material of the strip of aluminum foil was A1N30, the thickness was 6 μm, and the width was 300 mm. The planned coating surface of the aluminum foil strip was the surface on one side in the thickness direction of the aluminum foil strip.

  Next, the coating liquid is applied to the surface of the aluminum foil strip scheduled to be coated by the same coating method as in Example 1, whereby a scaly graphite particle layer is formed on the surface of the aluminum foil strip planned to be coated. A strip of coated foil was obtained.

And the solvent in scaly graphite particle layer was evaporated and removed from the scaly graphite particle layer by letting the strip of coating foil pass in a drying furnace. The coating amount of the scaly graphite particles in the scaly graphite particle layer was 10 g / m ² .

  Next, a plurality of coating foils having the same size and shape as in Example 1 were cut out from the strip of coating foil. And the laminated body was formed by laminating | stacking 100 coating foil.

  Next, the laminate was sintered with the same sintering apparatus and sintering conditions as in Example 1, thereby obtaining an aluminum-flaky graphite particle composite material. The thickness of the composite material was 1 mm. Moreover, the volume content of the scaly graphite particles in the composite material was 40% by volume with respect to the volume of the composite material.

  In the composite material, aluminum as a metal matrix sufficiently permeates between the scaly graphite particles, and there are almost no voids inside the composite material, and the density of the composite material is 99% of the theoretical density of the composite material. The sintered state of the composite material was good.

  Further, the thermal conductivity in the plane direction of the composite material was 438 W / (m · K), which was higher than the thermal conductivity of aluminum.

  Further, when the average thickness of the aluminum layer of the composite material and the average thickness of the scaly graphite particle dispersion layer were calculated in the same manner as in Example 1, the average thickness of the aluminum layer was 6 μm, and the scaly graphite particle dispersion layer The average thickness was 4 μm. Therefore, X was 0.67.

  Further, a bending test piece having the same dimensions and shape as in Example 1 was cut out from the composite material, and the test piece was bent under the same bending conditions as in Example 1. As a result, the aluminum layer and scaly graphite particles of the test piece were obtained. Systematic peeling and breakage were observed for the dispersed layer.

<Comparative example 2>
The same coating solution as that used in Example 1 was prepared. Moreover, the strip of aluminum foil of the following structure was prepared as a strip of metal foil.

  The material of the strip of aluminum foil was A1N30, the thickness was 15 μm, and the width was 300 mm. The planned coating surface of the aluminum foil strip was the surface on one side in the thickness direction of the aluminum foil strip.

  Next, the coating liquid is applied to the surface of the aluminum foil strip scheduled to be coated by the same coating method as in Example 1, whereby a scaly graphite particle layer is formed on the surface of the aluminum foil strip planned to be coated. A strip of coated foil was obtained.

And the solvent in scaly graphite particle layer was evaporated and removed from the scaly graphite particle layer by letting the strip of coating foil pass in a drying furnace. The coating amount of the scaly graphite particles in the scaly graphite particle layer was 80 g / m ² .

  Next, a plurality of coating foils having the same size and shape as in Example 1 were cut out from the strip of coating foil. And the laminated body was formed by laminating | stacking 20 coating foil.

  Next, the laminate was sintered with the same sintering apparatus and sintering conditions as in Example 1, thereby obtaining an aluminum-flaky graphite particle composite material. The thickness of the composite material was 1 mm. Moreover, the volume content of the scaly graphite particles in the composite material was 70% by volume with respect to the volume of the composite material.

  In the composite material, aluminum as a metal matrix does not permeate so much between the scaly graphite particles, and voids exist between the scaly graphite particles and between the aluminum foils inside the composite material. The bonded state was not so good, and the thermal conductivity of the composite material could not be measured.

  Moreover, when the average thickness of the aluminum layer of the composite material and the average thickness of the flaky graphite particle dispersion layer were calculated by the same method as in Example 1, the average thickness of the aluminum layer was 16 μm, and the flaky graphite particle dispersion layer The average thickness was 33 μm. Therefore, X was 2.1.

  Further, a bending test piece having the same dimensions and shape as in Example 1 was cut out from the composite material, and the test piece was bent under the same bending conditions as in Example 1. As a result, the aluminum layer and scaly graphite particles of the test piece were obtained. Systematic peeling and breakage were observed for the dispersed layer.

<Comparative Example 3>
The same scaly graphite particles as the scaly graphite particles used in Example 1 were prepared. Moreover, an aluminum paste was prepared. The aluminum paste had a solid content of aluminum of 70% by mass obtained by adding mineral spirit and fatty acid to scaly aluminum powder.

  Next, 61 g of scaly graphite particles, 160 g of aluminum paste, and 100 g of 10% polystyrene-cumene solution were mixed, kneaded and dispersed to form a paste. Then, this paste-like material was formed into a sheet on a PET sheet by the doctor blade method, and then air-dried for 1 day. Next, the PET sheet was peeled off to produce a green sheet of aluminum powder-flaky graphite particles. The thickness of the green sheet was 1 mm.

  Next, a plurality of sheet pieces having the same size and shape as in Example 1 were cut out from the green sheet. And the laminated body was formed by laminating | stacking 10 sheet | seat pieces.

  Next, the laminate was sintered with the same sintering apparatus and sintering conditions as in Example 1, thereby obtaining an aluminum-flaky graphite particle composite material. The thickness of the composite material was 1 mm. Moreover, the volume content of the scaly graphite particles in the composite material was 40% by volume with respect to the volume of the composite material.

  In the composite material, aluminum as a metal matrix sufficiently permeates between the scaly graphite particles, and there are almost no voids inside the composite material, and the density of the composite material is 99% of the theoretical density of the composite material. The sintered state of the composite material was good.

  Further, the thermal conductivity in the plane direction of the composite material was 440 W / (m · K), which was higher than the thermal conductivity of aluminum. In this composite material, the planar direction of the composite material means a direction perpendicular to the direction in which the laminate is pressed during sintering of the laminate.

  In the composite material, the scaly graphite particles oriented in the plane direction of the composite material are randomly dispersed three-dimensionally in aluminum as the metal matrix, and the average thickness of the aluminum layer and the scaly graphite particle dispersion layer The average thickness of each could not be defined.

  Further, a bending test piece having the same size and shape as in Example 1 was cut out from the composite material, and the test piece was bent under the same bending conditions as in Example 1. As a result, an aluminum matrix structure and aluminum / flaky graphite were obtained. Systematic peeling and breakage were observed at the particle interface.

  The above results are summarized in Table 1.

  In addition, the meaning of the code | symbol in the "evaluation of a bending test" column in the same table is as follows.

○: Good ×: Bad (break)

  The present invention is applicable to a metal-carbon particle composite material in which scaly graphite particles as carbon particles are dispersed in a metal matrix.

1: scale-like graphite particles 2: binder 3: solvent 5: coating solution 10: metal foil 10A: strip material of metal foil 11: scale-like graphite particle layer 12: coating foil 12A: strip material 15 of coating foil: Laminate 20: Metal-carbon particle composite material 21: Scale-like graphite particle dispersion layer 22: Metal layer 23: Metal matrix 30: Coating device

Claims (2)

A metal layer composed of a metal matrix and a scaly graphite particle dispersion layer in which scaly graphite particles are dispersed in the metal matrix are joined and integrated in a state where a plurality of layers are alternately laminated,
The average thickness of the metal layer is in the range of 12-100 μm;
The average thickness of the scaly graphite particle dispersion layer is in the range of 1 to 100 μm,
A metal-carbon particle composite material in which X is in the range of 0.1 to 1, where the ratio of the average thickness of the metal layer to the average thickness of the scaly graphite particle dispersion layer is 1: X.   The metal-carbon particle composite material according to claim 1, wherein the metal matrix is aluminum or copper.

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