WO2022209604A1

WO2022209604A1 - Aluminum fiber structure and aluminum composite material

Info

Publication number: WO2022209604A1
Application number: PCT/JP2022/009679
Authority: WO
Inventors: 英輝森内; 昭康小柳津
Original assignee: 株式会社巴川製紙所
Priority date: 2021-03-30
Filing date: 2022-03-07
Publication date: 2022-10-06
Also published as: TW202248589A; KR20230142789A; TWI809764B; JPWO2022209604A1; EP4317901A1

Abstract

This aluminum composite material (1, 2, 3, 4, 5) is obtained by combining an aluminum fiber structure (10) and a composite material (70, 80, 110). With respect to the aluminum fiber structure (10), aluminum fibers (20) are partially bonded with each other, and an alumina layer 30 is formed on the surface of each one of the aluminum fibers (20). A plurality of alumina projections (40), each of which has a height that is greater than the thickness of the alumina layer (30), is formed on the surfaces of the aluminum fibers (20) or the alumina layer (30). The alumina projections (40) and at least a part of the composite material (70, 80, 110) are in contact with each other.

Description

Aluminum fiber structures and aluminum composites

The present invention relates to an aluminum fiber structure and an aluminum composite material.

Conventionally, a metal fiber structure molded from metal fibers may be used as a medium for heat transfer in heat exchangers. Japanese Patent Laid-Open Publication No. 2011-007365 (JP2011-007365A) shows an example in which an aluminum fiber structure made of aluminum fibers is used as the metal fiber structure.

The aluminum fiber structure disclosed in Japanese Patent Laid-Open Publication No. 2011-007365 is made by filling aluminum fibers having an average fiber thickness of 50 to 200 μm and an average fiber length of 20 to 1000 mm into a mold having a predetermined shape. , The filled aluminum fibers are compressed to form a compression molded body having a bulk density of 30% or more, and the compression molded body is heated at 600 to 650 ° C. in an inert gas atmosphere to diffusion bond the entangled aluminum fibers. It is produced by forming a porous sintered molded body by pressing and then hydrophilizing the surface of the aluminum fiber.

The aluminum fiber structure disclosed in Japanese Patent Laid-Open No. 2011-007365 has a large linear expansion coefficient, so when it is combined with glass or ceramic, for example, the linear expansion coefficient of these glasses or ceramics is relatively small, there is a problem that separation may occur due to the difference in coefficient of linear expansion between the two when the temperature of the surrounding environment changes significantly.

The present invention has been made in consideration of such points, and provides an aluminum fiber structure having a small coefficient of linear expansion, and providing an aluminum fiber structure that maintains its properties even when the temperature of the surrounding environment changes significantly. An object of the present invention is to provide an aluminum composite material that is less prone to peeling between a body and the composite material.

The aluminum fiber structure of the present invention is
An aluminum fiber structure in which aluminum fibers are partially bound together,
An alumina layer is formed on the surface of the aluminum fiber,
A plurality of protrusions of alumina having a height greater than the thickness of the alumina layer are formed on the surface of the aluminum fiber or the alumina layer.

The aluminum composite material of the present invention is
An aluminum composite material in which the above-described aluminum fiber structure and a composite material are combined,
The protrusion of the alumina and at least part of the composite material are in contact with each other.

1 is a schematic configuration diagram that schematically shows a first example of the configuration of an aluminum composite material according to an embodiment of the present invention; FIG. FIG. 4 is a schematic configuration diagram schematically showing a second example of the configuration of the aluminum composite material according to the embodiment of the invention; FIG. 5 is a schematic configuration diagram schematically showing a third example of the configuration of the aluminum composite material according to the embodiment of the invention; FIG. 5 is a schematic configuration diagram schematically showing a fourth example of the configuration of the aluminum composite material according to the embodiment of the invention; FIG. 6 is a schematic configuration diagram schematically showing a fifth example of the configuration of the aluminum composite material according to the embodiment of the invention; 1 is a photograph of the surface of an aluminum fiber structure of an aluminum composite according to an embodiment of the present invention; 7 is a photograph showing a cut surface when the aluminum fiber structure shown in FIG. 6 is cut. 8 is a photograph showing an enlarged part of the cross section of the aluminum fiber structure shown in FIG. 7; BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows roughly the manufacturing method of the aluminum fiber structure of the aluminum composite material by embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 are schematic configuration diagrams schematically showing various examples of configurations of aluminum composite materials according to embodiments of the present invention. FIG. 6 is a photograph of the surface of the aluminum fiber structure of the aluminum composite material according to the present embodiment. 7 is a photograph showing a cut surface when the aluminum fibrous structure shown in FIG. 6 is cut, and FIG. 8 is a photograph showing an enlarged part of the cross section of the aluminum fibrous structure shown in FIG. is. 9A and 9B are explanatory diagrams schematically showing a method of manufacturing an aluminum fiber structure made of an aluminum composite material according to the present embodiment.

The aluminum

composite materials

1, 2, 3, 4, and 5 according to the present embodiment are composites of the aluminum fiber structure 10 and a composite material composed of a material different from aluminum. Various examples of such aluminum

composite materials

1, 2, 3, 4 and 5 will be described with reference to FIGS. 1 to 5. FIG.

As shown in FIG. 1, the aluminum composite material 1 as a first example is an aluminum fiber structure 10 completely impregnated with a resin 70 . The material of the resin 70 is not particularly limited, but examples include epoxy, polyolefin, styrenic polymer, polyether, polyurea, acrylic polymer, polyurethane, polyester, polyamide, polysiloxane, polysaccharide, poly Peptides, polynucleotides, polyvinyl alcohol, polyacrylamide, etc., as well as mixtures thereof are used. Specifically, the two aluminum fiber structures 10 are completely impregnated with the resin 70, so that the aluminum fiber structures 10 are positioned near each of the front side and the back side of the resin 70. . Note that the aluminum fiber structure 10 does not protrude outward from the front and back surfaces of the resin 70 .

As shown in FIG. 2, the aluminum composite material 2 as a second example is an aluminum fiber structure 10 partially impregnated with a resin 70 . Specifically, by partially impregnating the resin 70 into the two aluminum fiber structures 10, the aluminum fiber structures 10 are positioned near the front side and the back side of the resin 70, respectively. Thus, the aluminum fiber structure 10 protrudes outward from the front and back surfaces of the resin 70, respectively.

As shown in FIG. 3, in the aluminum composite material 3 as the third example, two aluminum fiber structures 10 are made of a metal paste other than aluminum, such as silver paste, copper paste, nickel paste, silver solder, copper solder, They are adhered by an adhesive layer 80 made of an adhesive such as tin or solder.

As shown in FIG. 4, in the aluminum composite material 4 as a fourth example, a metal part 90 such as a copper plate is bonded to one surface of the aluminum fiber structure 10 using an adhesive such as a metal paste other than aluminum. It is adhered by layer 80 .

As shown in FIG. 5, in the aluminum composite material 4 as the fifth example, a metal component 90 is formed on one surface of an aluminum fiber structure 10 by an adhesive layer 80 made of an adhesive such as a metal paste other than aluminum. An alumina plate 100 is bonded to the other surface of the aluminum fiber structure 10 with an adhesive layer 110 made of an adhesive such as glass (for example, water glass, fritted glass, glass paste). .

Next, the configuration of the aluminum fiber structure 10 will be described. As shown in FIGS. 6 to 8, in the aluminum fiber structure 10 according to the present embodiment, the aluminum fibers 20 are partially bonded to each other, and the alumina layer 30 is formed on the surface of the aluminum fibers 20. It is Further, as shown in FIG. 8, on the surface of the aluminum fiber 20 or the alumina layer 30, a plurality of protrusions 40 of alumina having a height greater than the thickness of the alumina layer 30 are formed. In FIG. 8, reference numeral 22 indicates a portion of the surface of the aluminum fiber 20 where the alumina layer 30 and the protrusions 40 are not formed.

In such an aluminum fiber structure 10, the portion where the alumina layer 30 is formed tends to expand or contract due to temperature change, while the portion where the plurality of alumina protrusions 40 is formed expands or contracts due to temperature change. Hateful. As described above, since the coefficient of linear expansion of the entire aluminum fiber structure 10 is partially uneven, the coefficient of linear expansion can be reduced as a whole.

The aluminum fiber 20 has a length within the range of 0.2 to 15 mm and a diameter within the range of 0.01 to 0.100 mm. The length of the aluminum fiber 20 can be confirmed by actually measuring it through photographic observation using an SEM, an optical microscope, or the like.

The alumina layer 30 is formed by oxidizing the aluminum fibers 20 in the atmosphere. Alumina layer 30 is generally uniformly formed on the surfaces of aluminum fibers 20 . The thickness of such alumina layer 30 is in the range of 10 nm to 10 μm, preferably 100 nm to 7 μm, more preferably 1 μm to 5 μm.

The projections 40 are formed from the material eluted from the aluminum fibers 20 by sintering the aluminum fibers 20 at 700°C or higher. A method of sintering the aluminum fibers 20 to produce the aluminum fiber structure 10 will be described later. If the sintering temperature for the aluminum fibers 20 is lower than 700° C., a sufficient amount of alumina is not eluted from the aluminum fibers 20, and projections 40 with a sufficient height cannot be obtained.

Also, as described above, the height of the protrusions 40 with respect to the surface of the aluminum fibers 20 or the alumina layer 30 is greater than the thickness of the alumina layer 30 . Specifically, the height of the projections 40 with respect to the surface of the aluminum fiber 20 or alumina layer 30 is 10 nm to 10 μm, preferably 100 nm to 7 μm, more preferably 1 μm to 5 μm. This increases the bonding strength between the aluminum fibers 20 and the projections 40 . Here, if the height of the protrusions 40 with respect to the surface of the aluminum fiber 20 or the alumina layer 30 is too small, specifically smaller than 10 nm, the difference between the thickness of the alumina layer 30 and the height of the protrusions 40 does not increase, and the aluminum fiber structure 10 cannot be partially biased in the coefficient of linear expansion. In addition, when the height of the protrusions 40 relative to the surface of the aluminum fibers 20 or the alumina layer 30 is too large, specifically, when it is greater than 10 μm, there is a problem that large gaps are formed between the aluminum fibers 20. There is

In the cross section of the aluminum fiber structure 10 as shown in FIGS. 7 and 8, the total coverage of the portions covered by the protrusions 40 on the surface of the aluminum fiber 20 is preferably 20% or more, and 40% or more. It is even more preferable to have Almost the entire surface of the aluminum fiber 20 is covered with an alumina layer 30, and projections 40 are partially formed on the alumina layer 30. As shown in FIG. The coverage rate of the portion covered by the projections 40 on the surface of the aluminum fiber 20 is the portion covered by the projections 40 in the cross section of the aluminum fiber structure 10 (specifically, from the point where the mountain of the projections 40 starts to descend ) can be calculated by dividing the length of the alumina layer 30 by the total length of the alumina layer 30 . When the coverage of the protrusions 40 on the surface of the aluminum fiber 20 is less than 20%, the proportion of the protrusions 40 in the aluminum fiber structure 10 is relatively small, so the coefficient of linear expansion of the aluminum fiber structure 10 does not decrease. There's a problem.

In addition, at least some of the plurality of projections 40 are in contact across the alumina layer 30 of the plurality of aluminum fibers 20 . In this case, since the aluminum fibers 20 are connected to each other by the projections 40, the aluminum fibers 20 are less likely to move relative to each other, so that the linear expansion coefficient of the aluminum fiber structure 10 can be further reduced. Further, when the aluminum fiber structure 10 and the composite material (for example, the resin 70, the adhesive layer 80, the adhesive layer 110, etc. described above) are combined, the composite material that enters the gaps of the aluminum fiber structure 10 forms the projections 40. come into contact.

Further, the space factor of the aluminum fibers 20 in the aluminum fiber structure 10 according to the present embodiment is within the range of 20% to 90%. Such a space factor of the aluminum fibers 20 is calculated by calculating the ratio of the area occupied by the aluminum fibers 20 to the inner area of the outer edge of the aluminum fiber structure 10 on the cut surface when the aluminum fiber structure 10 is cut. can ask. By setting the space factor of the aluminum fibers 20 in the aluminum fiber structure 10 within the range of 20% to 90%, the aluminum fiber structure 10 can achieve both lightness and strength. That is, when the space factor of the aluminum fibers 20 in the aluminum fiber structure 10 is less than 20%, sufficient strength cannot be obtained, and the space factor of the aluminum fibers 20 in the aluminum fiber structure 10 is 90%. If it is larger than , there is a problem that weight reduction cannot be achieved. Moreover, when the space factor of the aluminum fibers 20 in the aluminum fiber structure 10 is 20% or more, the amount of the aluminum fibers 20 is sufficient, so that appropriate homogeneity can be obtained. Moreover, if the space factor of the aluminum fibers 20 in the aluminum fiber structure 10 is 90% or less, desired flexibility can be obtained in addition to appropriate homogeneity.

Further, in the aluminum fiber structure 10 according to the present embodiment, a plasma resistant layer may be formed on the surfaces of the alumina layer 30 and the protrusions 40 . Here, the plasma resistant layer may contain metal oxide or aluminum nitride. Metal oxides include, for example, at least one of zirconium oxide, yttrium oxide, magnesium oxide, zinc oxide, sapphire, and quartz glass. In this case, a composite material of the aluminum fiber structure 10 and the plasma resistant layer can be provided, and the composite material has excellent plasma resistance. Such a composite material of the aluminum fibrous structure 10 and the plasma-resistant layer is manufactured by applying a glaze containing zirconia, yttria, etc. to the alumina layer 30 and the protrusions 40 of the aluminum fibrous structure 10 and then heating it at a high temperature. be able to.

As shown in FIG. 9(a), the aluminum fibers 20 are molded into a sheet inside a molding container 50 and pressed. As a result, the aluminum fibers 20 can be brought into close contact with each other. Further, as shown in FIG. 9(b), the aluminum fibers 20 are sintered by heating them at 700° C. or higher inside the sintering equipment 60. As shown in FIG. This forms the aluminum fiber structure 10 . As a method of heating the aluminum fibers 20, there is a method of heating the surface of the aluminum fibers 20 with hot air or the like, but the method is not limited to such a method. As a method for heating the aluminum fibers 20, an electric heating method may be used. Further, as described above, when the aluminum fibers 20 are sintered at 700° C. or higher, alumina is eluted from the aluminum fibers 20 , and the eluted alumina is solidified at room temperature to form the projections 40 . Also, by exposing the aluminum fiber structure 10 to the atmosphere, the aluminum fibers 20 are oxidized to form the alumina layer 30 .

In summary, according to the aluminum fiber structure 10 of the present embodiment, the aluminum fibers 20 are partially bonded to each other, and the alumina layer 30 is formed on the surfaces of the aluminum fibers 20 . Further, on the surface of the aluminum fiber 20 or the alumina layer 30, a plurality of protrusions 40 of alumina having a height greater than the thickness of the alumina layer 30 are formed. In such an aluminum fiber structure 10, the portion where the alumina layer 30 is formed tends to expand or contract due to temperature change, while the portion where the plurality of alumina projections 40 are formed expands or contracts due to temperature change. Since the coefficient of linear expansion of the entire aluminum fiber structure 10 is partially uneven, the coefficient of linear expansion can be reduced as a whole.

In addition,

aluminum composite materials

1, 2, and 3 in which such an aluminum fiber structure 10 and a composite material composed of a composite material different from aluminum (for example, a resin 70, an adhesive layer 80, an adhesive layer 110, etc.) are combined. , 4, 5, there is contact between the alumina protrusions 40 and at least a portion of the composite material. Even when the temperature of the surrounding environment changes significantly, separation between the aluminum fiber structure 10 and the composite material is less likely to occur. More specifically, the composite material that has entered the gaps of the aluminum fiber structure 10 is caught on the protrusions 40 of the aluminum fiber structure 10, so that even if the composite material is difficult to adhere to aluminum, the aluminum fiber structure will adhere to the composite material. 10 can be strongly adhered.

For example, in the aluminum composite materials 1 according to the first and second examples, the resin 70 entering the gaps of the aluminum fiber structure 10 is caught on the projections 40 of the aluminum fiber structure 10, and thus the resin 70 is difficult to adhere to the aluminum. Even in this case, the aluminum fiber structure 10 can be strongly adhered to the resin 70 .

In addition, according to the aluminum composite materials 3 and 4 according to the third and fourth examples, the adhesive that has entered the gaps of the aluminum fiber structure 10 is caught on the projections 40 of the aluminum fiber structure 10, and the adhesion layer 80 The aluminum fiber structure 10 can be firmly adhered. This makes it difficult for the two aluminum fiber structures 10 to separate from each other in the aluminum composite material 3 according to the third example. Further, in the aluminum composite material 4 according to the fourth example, the aluminum fiber structure 10 is less likely to peel off from the metal component 90 such as a copper plate. In addition, even if the adhesion between the metal component 90 and the adhesive layer 80 is weak, the linear expansion coefficient of the aluminum fiber structure 10 is small. Hard to peel off.

Further, according to the aluminum composite material 5 according to the fifth example, the adhesive that has entered the gaps of the aluminum fiber structure 10 is caught on the protrusions 40 of the aluminum fiber structure 10, and the aluminum fibers are attached to the

adhesive layers

80 and 110, respectively. The structure 10 can be strongly adhered. This makes it difficult for the aluminum fiber structure 10 to peel off from each of the metal component 90 and the alumina plate 100 . In this case, even if there is a difference in the coefficient of linear expansion between the metal component 90 and the alumina plate 100, the coefficient of linear expansion of the aluminum fiber structure 10 is small. Separation is less likely to occur between the structure 10 and between the alumina plate 100 and the aluminum fiber structure 10 .

Hereinafter, the present invention will be described in more detail using examples and comparative examples.

<Example 1>
An aluminum fibrous structure was manufactured by the following procedure. First, a plurality of aluminum fibers made of A1070, having a fiber diameter of 50 μm and an average length of 2 mm were formed into a sheet. After that, the aluminum fibers were sintered by heating them at 700° C. inside the sintering equipment. This produced an aluminum fiber structure.

When the cut surface of the produced aluminum fiber structure was checked with a microscope, an alumina layer was formed on the surface of the aluminum fiber, and the alumina layer or the surface of the aluminum fiber had a thickness greater than the thickness of the alumina layer. It was found that a plurality of protrusions of alumina having a large diameter were formed. In addition, in the cross section of the aluminum fiber structure, the total coverage of the alumina layer and the protrusions on the surface of the aluminum fiber was 24%, and the space factor of the aluminum fiber in the aluminum fiber structure was 75%. Each physical property of the aluminum fiber structure is shown in Table 1 below.

<Examples 2 to 4>
Aluminum fiber structures were produced in the same manner as in Example 1, except that the aluminum fibers were sintered by heating them at 750°C, 800°C, and 850°C, respectively, inside the sintering equipment. When the cut surfaces of the aluminum fiber structures produced according to Examples 2 to 4 were cut and confirmed with a microscope, an alumina layer was formed on the surface of the aluminum fibers, and alumina was formed on the surface of the alumina layer or the aluminum fibers. It was found that a plurality of protrusions of alumina having a height greater than the thickness of the layer were formed. The physical properties of the aluminum fibrous structures produced according to Examples 2 to 4 are shown in Table 1 below.

<Examples 5 to 8>
The fiber diameter and average length of each of the plurality of aluminum fibers are shown in Table 1, and the aluminum fibers are sintered by heating at the temperature shown in Table 1 (800 ° C. or 900 ° C.) inside the sintering equipment. An aluminum fibrous structure was produced in the same manner as in Example 1 except for the above. When the cut surfaces of the aluminum fiber structures produced according to Examples 5 to 8 were cut and confirmed with a microscope, an alumina layer was formed on the surfaces of the aluminum fibers, and alumina was formed on the surfaces of the alumina layers or the aluminum fibers. It was found that a plurality of protrusions of alumina having a height greater than the thickness of the layer were formed. The physical properties of the aluminum fibrous structures produced according to Examples 5 to 8 are shown in Table 1 below.

<Example 9>
Aluminum fibers were formed into a sheet as in Example 1, and then sintered by heating the aluminum fibers at 900° C. inside a sintering facility. A glaze containing yttria was applied to the surface of the aluminum fiber structure, and then heated at a high temperature. When the cut surface of the aluminum fiber structure thus produced was checked under a microscope, an alumina layer was formed on the surface of the aluminum fiber, and the thickness of the alumina layer was observed on the surface of the alumina layer or the aluminum fiber. It was found that a plurality of protrusions of alumina having a height greater than the height were formed. Moreover, in such an aluminum fibrous structure, a plasma-resistant layer containing yttrium oxide was formed on the surface of the alumina layer and the protrusions. Each physical property value of the manufactured aluminum fibrous structure according to Example 9 is as shown in Table 1 below.

<Example 10>
Aluminum fibers were formed into a sheet as in Example 1, and then sintered by heating the aluminum fibers at 900° C. inside a sintering facility. Then, after applying a glaze containing zirconia to the surface of the aluminum fiber structure, the structure was heated at a high temperature. When the cut surface of the aluminum fiber structure thus produced was checked under a microscope, an alumina layer was formed on the surface of the aluminum fiber, and the thickness of the alumina layer was observed on the surface of the alumina layer or the aluminum fiber. It was found that a plurality of protrusions of alumina having a height greater than the height were formed. Also, in such an aluminum fibrous structure, a plasma-resistant layer containing zirconium oxide was formed on the surfaces of the alumina layer and the protrusions. Each physical property value of the manufactured aluminum fibrous structure according to Example 10 is as shown in Table 1 below.

<Comparative Examples 1 and 2>
Aluminum fiber structures according to Comparative Examples 1 and 2 were produced in the same manner as in Example 1, except that the aluminum fibers were sintered by heating them at 680° C. and 600° C., respectively, inside the sintering equipment. Microscopic examination of the cut surfaces of the produced aluminum fiber structures according to Comparative Examples 1 and 2 revealed that an alumina layer was formed on the surfaces of the aluminum fibers. It was found that no protrusions of alumina were formed on the surface. The physical property values of the manufactured aluminum fibrous structures according to Comparative Examples 1 and 2 are shown in Table 1 below.
<Comparative Example 3>
As Comparative Example 3, a plate-like body made of aluminum whose material is A1070 was used.

<Evaluation>
The coefficient of linear expansion at 40° C. was measured for the aluminum fibrous structures according to Examples 1-10 and Comparative Examples 1-3. The survey results are shown in Tables 1 and 2 below. In Tables 1 and 2, the coverage rate refers to the coverage rate of the protrusions on the surface of the aluminum fiber in the cross section when the aluminum fiber structure is cut. It was calculated by dividing the length of the alumina layer at the covered portion (specifically, the portion from the point where the mountain of the protrusion starts to descend to the point where it ends) by the total length of the alumina layer. Incidentally, in Comparative Examples 1 to 3, the coverage is 0%, which means that no protrusions of alumina are formed. In Tables 1 and 2, the space factor refers to the space factor of the aluminum fibers in the aluminum fiber structure, and the inside of the outer edge of the aluminum fiber structure on the cut surface when the aluminum fiber structure is cut. The ratio of the area occupied by aluminum fibers to the area of .

When the cut surfaces of the aluminum fiber structures according to Examples 1 to 10 were checked under a microscope, an alumina layer was formed on the surface of the aluminum fibers, and the thickness of the alumina layer was formed on the surface of the alumina layer or the aluminum fibers. It was found that a plurality of protrusions of alumina having a height greater than the height were formed. On the other hand, when the cut surfaces obtained by cutting the aluminum fiber structures according to Comparative Examples 1 to 3 were checked under a microscope, an alumina layer was formed on the surface of the aluminum fibers. It was found that no protrusions of alumina were formed. Also, the linear expansion coefficients of the aluminum fibrous structures according to Examples 1 to 10 and Comparative Examples 1 to 3 were measured. The linear expansion coefficients of the aluminum fibrous structures according to Examples 1 to 10 were all 22.0 or less, whereas the linear expansion coefficients of the aluminum fibrous structures according to Comparative Examples 1 to 3 were all greater than 23.0. became. From the above results, it can be seen that the linear expansion coefficient of the aluminum fiber structure can be reduced when the aluminum fibers are sintered by heating them at 700° C. or higher inside the sintering equipment.

<Example 11>
An aluminum composite material as shown in FIG. 2 was produced by bonding two aluminum fiber structures with a resin. The aluminum composite material according to Example 11 has an aluminum fiber structure partially impregnated with a resin. Specifically, by partially impregnating the resin into the two aluminum fiber structures, the aluminum fiber structures are positioned near each of the front side and the back side of the resin. Aluminum fiber structures protrude outward from the front and back surfaces of the resin, respectively. As the aluminum fiber structure, the aluminum fiber structure according to Example 1 was used, and each aluminum fiber structure had a thickness of 3.0 mm and a space factor of 75%. Epoxy resin was used as the resin for the adhesive layer, and the thickness of this adhesive layer was 125 μm.

<Example 12>
An aluminum composite material as shown in FIG. 3 was produced by bonding two aluminum fiber structures with an adhesive layer made of a silver paste adhesive. As the aluminum fiber structure, the aluminum fiber structure according to Example 1 was used, and each aluminum fiber structure had a thickness of 3.0 mm and a space factor of 75%. The thickness of the adhesive layer made of the silver paste adhesive was 12 μm.

<Example 13>
An aluminum composite material as shown in FIG. 4 was produced by adhering a copper plate to one surface of an aluminum fiber structure with an adhesive layer made of a copper paste adhesive. As the aluminum fiber structure, the aluminum fiber structure according to Example 3 was used, and each aluminum fiber structure had a thickness of 1.0 mm and a space factor of 72%. The thickness of the adhesive layer made of copper paste adhesive was 48 μm. The copper plate used was made of C1100, had a thickness of 5.0 mm, and had a space factor of 100%.

<Example 14>
By bonding a copper plate to one surface of an aluminum fibrous structure with an adhesive layer made of a copper paste adhesive, and bonding an alumina plate to the other surface of the aluminum fibrous structure with an adhesive layer made of a glass paste adhesive. An aluminum composite material as shown in FIG. 5 was produced. As the aluminum fiber structure, the aluminum fiber structure according to Example 3 was used, and each aluminum fiber structure had a thickness of 1.0 mm and a space factor of 72%. The thickness of the adhesive layer made of copper paste adhesive was 48 μm. The copper plate used was made of C1100, had a thickness of 0.5 mm, and had a space factor of 100%. The thickness of the adhesive layer made of the glass paste adhesive was 27 μm. The alumina plate used had a thickness of 1.0 mm and a space factor of 100%.

<Comparative Example 4>
Compared to Example 14, instead of the aluminum fiber structure, a copper plate was bonded to one surface of an aluminum plate with an adhesive layer made of a copper paste adhesive, and an alumina plate was bonded to the other surface of the aluminum plate with a glass paste adhesive. An aluminum composite material as shown in FIG. 5 was produced by bonding with an adhesive layer consisting of. An aluminum plate having a thickness of 1.0 mm and a space factor of 100% was used. The thickness of the adhesive layer made of copper paste adhesive was 43 μm. The copper plate used was made of C1100, had a thickness of 0.5 mm, and had a space factor of 100%. The thickness of the adhesive layer made of the glass paste adhesive was 34 μm. The alumina plate used had a thickness of 1.0 mm and a space factor of 100%.

<Comparative Example 5>
An alumina composite material was produced by adhering a copper plate to one surface of an alumina plate with an adhesive layer made of a glass paste adhesive. An alumina plate having a thickness of 1.0 mm and a space factor of 100% was used. The thickness of the adhesive layer made of the glass paste adhesive was 32 μm. The copper plate used was made of C1100, had a thickness of 0.5 mm, and had a space factor of 100%.

<Evaluation>
Adhesion and adhesion strength were evaluated for the aluminum composite materials and alumina composite materials according to Examples 11-14 and Comparative Examples 4-5. For adhesion, heat shock test (500 cycles between -40 ° C. and 120 ° C., holding time total 30 minutes), and whether or not peeling occurred was visually observed. When no peeling occurred, it was evaluated as "O", and when peeling occurred partially or the composite member lifted, it was evaluated as "x". As for the adhesive strength, the rate of change in adhesive strength was calculated before and after the heat shock test was performed on the aluminum composite materials and alumina composite materials according to Examples 11 to 14 and Comparative Examples 4 and 5. Such adhesion strength was measured by measuring tensile strength according to JIS K 6854-2:1999 (ISO8510-2:1990). When the rate of change in adhesive strength before and after the heat shock test was less than 10%, it was evaluated as "⊚"; when it was less than 30%, it was evaluated as "◯"; The evaluation results are shown in Table 3 below.

As shown in the evaluation results in Table 3, when the aluminum fiber structure was used as the aluminum composite material, the adhesiveness and adhesive strength were good. Specifically, peeling is less likely to occur, and the adhesive strength is less likely to change due to temperature changes in the surrounding environment. On the other hand, when an aluminum plate or an alumina plate was used instead of the aluminum fiber structure as the aluminum composite material, the adhesiveness and bonding strength were inferior to those when the aluminum fiber structure was used. Thus, when the aluminum fibrous structure was used as the aluminum composite material, even when the temperature of the surrounding environment changed significantly, separation between the aluminum fibrous structure and the composite material was less likely to occur.

Claims

An aluminum fiber structure in which aluminum fibers are partially bound together,
An alumina layer is formed on the surface of the aluminum fiber,
An aluminum fiber structure, wherein a plurality of protrusions of alumina having a height greater than the thickness of the alumina layer are formed on the surface of the aluminum fiber or the alumina layer.
The aluminum fiber structure according to claim 1, wherein at least some of the plurality of projections are in contact across the alumina layer of the plurality of aluminum fibers.
The aluminum fiber structure according to claim 1 or 2, wherein the height of said protrusions with respect to said surface of said aluminum fibers or said alumina layer is in the range of 10 nm to 10 µm.
The aluminum fibrous structure according to any one of claims 1 to 3, wherein the alumina layer has a thickness in the range of 10 nm to 10 µm.
The aluminum fibrous structure according to any one of claims 1 to 3, characterized in that 20% or more of the projections cover the surfaces of the aluminum fibers in the cross section of the aluminum fibrous structure.
The aluminum fibrous structure according to any one of claims 1 to 5, characterized in that a total of 40% or more of the projections cover the surfaces of the aluminum fibers in the cross section of the aluminum fibrous structure.
The aluminum fibrous structure according to any one of claims 1 to 6, wherein a plasma-resistant layer is formed on the surfaces of the alumina layer and the protrusions.
The aluminum fiber structure according to claim 7, wherein said plasma-resistant layer contains metal oxide or aluminum nitride.
The aluminum fibrous structure according to any one of claims 1 to 8, wherein the protrusions are formed from substances eluted from the aluminum fibers by sintering the aluminum fibers at 700°C or higher.
The aluminum fibrous structure according to any one of claims 1 to 9, wherein the space factor of the aluminum fibers in the aluminum fibrous structure is in the range of 20% to 90%.
An aluminum composite material in which the aluminum fiber structure according to any one of claims 1 to 10 and a composite material are combined,
An aluminum composite, wherein the protrusions of the alumina are in contact with at least a portion of the composite.