heat transfer material

Abstract

This thermal conductor (10) comprises a thermal conduction part (20) including a metal, and a protrusion (30) that is attached to a surface of the thermal conduction part (20) and that extends from the thermal conduction part (20), the protrusion (30) having a core material (32) composed of a metal bulk body, and a metal fiber structure (34) fused around the core material (32).

Description

[Technical Field]

[0001] The present invention relates to a heat transfer body for transferring heat from or to a heat transfer object. [Background technology]

[0002] Various types of heat transfer devices have been used to transfer heat from or to objects to be cooled, such as heat-generating electrical or electronic components. For example, such heat transfer devices may have a flat base and a plurality of protrusions extending from the top surface of the base and positioned at the intersections of grid lines. Known examples of such heat transfer devices include the one disclosed in International Patent Application Publication WO 2017 / 061307 A1.

[0003] International Patent Application Publication WO2017 / 061307A1 discloses a heat transfer element having a flat base and a plurality of thin fins extending from the upper surface of the base and arranged substantially parallel to one another, the base and the fins being integrally formed. In this heat transfer element, when the substrate and the fins are viewed from the thickness direction, the fibrous filler is oriented in the planar direction in the base and the fins. Summary of the Invention

[0004] The conventional heat transfer bodies described above have a problem in that the strength of the fins themselves is low. Also, there is a demand for heat transfer bodies with improved thermal conductivity.

[0005] The present invention has been made in consideration of the above points, and an object of the present invention is to provide a heat transfer body that can increase the strength of the protrusions and obtain a sufficient heat transfer effect.

[0006] The heat transfer body of the present invention is a heat transfer portion including a metal; a protrusion attached to a surface of the heat transfer portion and extending from the heat transfer portion; Equipped with The protruding portion is characterized by having a core material made of a bulk metal body and a first metal fiber structure fused to the periphery of the core material. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view of a heat transfer element according to an embodiment of the present invention; [Figure 2] 2 is a vertical cross-sectional view showing an example of the configuration of a protrusion and a heat transfer portion of the heat transfer body shown in FIG. 1. FIG. [Figure 3] 10A and 10B are longitudinal cross-sectional views showing other examples of the configuration of the protrusions and heat transfer portions of the heat transfer body. [Figure 4] FIG. 10 is a vertical cross-sectional view showing still another example of the configuration of the protrusions and heat transfer portions of the heat transfer body. [Figure 5] FIG. 10 is a vertical cross-sectional view showing still another example of the configuration of the protrusions and heat transfer portions of the heat transfer body. [Figure 6] FIG. 10 is a cross-sectional view showing yet another example of the configuration of the protrusion of the heat transfer body. [Figure 7] 3 is a photograph of the heat transfer body shown in FIG. 1 cut along the longitudinal cross section shown in FIG. 2. [Figure 8] 6 is a photograph of the heat transfer body shown in FIG. 1 cut along the longitudinal cross section shown in FIG. 5. [Figure 9] 1 is a vertical cross-sectional view showing the configuration of a heat exchanger according to an embodiment and a modified example. [Figure 10] 10 is a cross-sectional view of the heat exchanger shown in FIG. 9 taken along the arrow AA. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figures 1 to 6 are diagrams showing a heat transfer body according to this embodiment. The heat transfer body according to this embodiment is attached to a heat transfer target, such as a heat-generating electric or electronic component, to dissipate heat from the heat transfer target. The heat transfer body according to this embodiment may also be used as part of a heat exchange unit that removes heat from the surrounding environment by being attached to the surface of a cooling unit through which a medium such as cooling water or cooling gas passes.

[0009] As shown in FIGS. 1 and 2, the heat transfer element 10 of this embodiment includes a flat heat transfer element 20 to be attached to an object to be heat-transferred, and a plurality of cylindrical protrusions 30 attached to the surface of the heat transfer element 20 and extending from the heat transfer element 20. Each protrusion 30 includes a core material 32 made of a bulk metal and a metal fiber structure 34 (first metal fiber structure) fused to the periphery of the core material 32. The metal fiber structure 34 is exposed. As shown in FIG. 2, each protrusion 30 is bonded to the heat transfer element 20 with an adhesive 36 containing a metal paste. Note that each protrusion 30 may be fused to the heat transfer element 20 instead of being glued. Each component of the heat transfer element 10 will now be described in detail. FIG. 7 is a photograph of the heat transfer element 10 shown in FIG. 1 cut along the longitudinal cross section shown in FIG. 2. This photograph was taken with a Nikon scanning electron microscope (SEM).

[0010] The heat transfer part 20 is made of a bulk metal such as copper or aluminum. Instead of a heat transfer part 20 made of a bulk metal, a heat transfer part made of a metal fiber sheet may be used. Metal-coated fibers may be used as the metal fibers contained in such a metal fiber sheet. The metal fibers contained in the metal fiber sheet are at least one of wet or dry nonwoven fabric, woven fabric, mesh, etc. Preferably, a metal fiber nonwoven fabric in which the metal fibers are bonded together is used as the metal fiber sheet.

[0011] In each protrusion 30, a metal fiber structure 34 is fused to the periphery of a core material 32 made of a bulk metal. The core material 32 is made of a bulk metal such as copper or aluminum. The metal fiber structure 34 contains a plurality of metal fibers. Metal-coated fibers may be used as the metal fibers contained in the metal fiber structure 34. The metal fibers contained in the metal fiber structure 34 are at least one of wet or dry nonwoven fabrics, woven fabrics, meshes, etc. Preferably, the metal fiber structure 34 is a metal fiber nonwoven fabric in which the metal fibers are bonded together.

[0012] Specific examples of metals constituting the metal fibers contained in the metal fiber structure 34 are not particularly limited, but may be selected from the group consisting of stainless steel, iron, copper, aluminum, bronze, brass, nickel, chromium, etc., or may be precious metals selected from the group consisting of gold, platinum, silver, palladium, rhodium, iridium, ruthenium, osmium, etc. Among these, copper fibers and aluminum fibers are preferred because they have excellent thermal conductivity and an appropriate balance between rigidity and plastic deformability.

[0013] Here, the ratio of the contact area of ​​the metal fiber structure 34 to the area of ​​the outer peripheral surface of the core material 32 at the bonding interface between the core material 32 and the metal fiber structure 34 of the protrusion 30 is preferably in the range of 20% to 80%, more preferably in the range of 30% to 70%, and particularly preferably in the range of 40% to 60%. When the ratio of the contact area of ​​the metal fiber structure 34 to the area of ​​the outer peripheral surface of the core material 32 is 20% or more, good heat transfer is achieved between the core material 32 and the metal fiber structure 34. When the ratio of the contact area of ​​the metal fiber structure 34 to the area of ​​the outer peripheral surface of the core material 32 is 80% or less, excessive fusion of the metal fiber structure 34 to the outer peripheral surface of the core material 32 can be prevented.

[0014] Furthermore, the space factor of the metal fibers in the metal fiber structure 34 is preferably in the range of 30% to 80%, and more preferably in the range of 40% to 70%. When the space factor of the metal fibers is 30% or more, the amount of metal fibers is sufficient to obtain appropriate homogeneity. When the space factor of the metal fibers is 80% or less, desired flexibility is obtained in addition to appropriate homogeneity. In this specification, the "space factor of the metal fibers in the metal fiber structure 34" refers to the ratio of the area where metal fibers exist to the volume of the metal fiber structure 34.

[0015] Furthermore, the metal fiber abundance ratio in a cross section of the metal fiber structure 34 is preferably in the range of 30% to 80%, and more preferably in the range of 40% to 70%. Specifically, the metal fiber abundance ratio in a cross section of the metal fiber structure 34 cut along a plane perpendicular to the longitudinal direction of the protrusion 30 (the vertical direction in FIG. 2) is preferably in the range of 30% to 80%. When the metal fiber abundance ratio is 30% or more, the amount of metal fibers is sufficient, and appropriate homogeneity can be obtained. When the metal fiber abundance ratio is 80% or less, desired flexibility can be obtained in addition to appropriate homogeneity.

[0016] Furthermore, when the metal fiber structure 34 of the protrusion 30 is attached to the heat transfer section 20 with the adhesive 36, the metal fiber structure 34 is compressed between the core material 32 and the heat transfer section 20 at the portion indicated by reference symbol 34a, thereby increasing the space factor of the metal fiber structure 34. In this case, the space factor of the metal fiber structure 34 at the bonding interface between the surface of the heat transfer section 20 and the protrusion 30 is preferably within a range of 40% to 80%. When the space factor of the metal fiber structure 34 is 40% or more, the heat transfer between the surface of the heat transfer section 20 and the protrusion 30 can be improved. When the space factor of the metal fiber structure 34 is 80% or less, the metal fiber structure 34 can be prevented from being excessively compressed.

[0017] Furthermore, it is preferable that the bulk material constituting the core material 32 in the protrusion 30 and the metal fibers constituting the metal fiber structure 34 are made of the same type of metal. In this case, it is possible to suppress the occurrence of interfacial corrosion between the core material 32 and the metal fiber structure 34. That is, if the type of metal constituting the metal fibers contained in the metal fiber structure 34 is different from the type of metal constituting the bulk material of the core material 32, a potential difference between the two metals may cause a current to flow, resulting in the formation of holes in the metal. However, this embodiment is not limited to this embodiment. In another embodiment of this embodiment, the bulk material constituting the core material 32 in the protrusion 30 and the metal fibers constituting the metal fiber structure 34 may be made of different types of metals.

[0018] In the heat transfer element 10 configured as described above, the protrusions 30 have the core material 32 made of a bulk metal and the metal fiber structure 34 fused to the periphery of the core material 32, which increases the strength of the protrusions 30 and provides a sufficient heat transfer effect. More specifically, the use of the core material 32 made of a bulk metal increases the strength of the protrusions 30. Furthermore, the metal fiber structure 34 fused to the periphery of the core material 32 is exposed, which increases the surface area of ​​the protrusions 30 and generates turbulence in the fluid flowing around the protrusions 30. This improves the heat transfer properties of the protrusions 30, allowing the heat transfer element 10 to provide a sufficient heat transfer effect.

[0019] Furthermore, one end of each protrusion 30 is bonded to the heat transfer portion 20 with the adhesive 36 containing metal paste, so that the bonding strength between each protrusion 30 and the heat transfer portion 20 can be increased.

[0020] The heat transfer body according to this embodiment is not limited to the configuration shown in Fig. 2. Fig. 3 is a vertical cross-sectional view showing another example of the configuration of the protrusions and heat transfer parts of the heat transfer body. In describing the heat transfer body 10a shown in Fig. 3, the same components as those in the heat transfer body 10 shown in Figs. 1 and 2 will be assigned the same reference numerals and their description will be omitted.

[0021] 1 and 2, the heat transfer element 10a shown in FIG. 3 differs from the heat transfer element 10 shown in FIGS. 1 and 2 in that the protrusions 30 are attached to the heat transfer portion 20 with an adhesive 36, but the metal fiber structure 34 of the protrusions 30 is fused to the heat transfer portion 20. When the metal fiber structure 34 of the protrusions 30 is fused to the heat transfer portion 20, the metal fiber structure 34 is compressed between the core material 32 and the heat transfer portion 20 at the portion indicated by reference symbol 34a, thereby increasing the space factor of the metal fiber structure 34. In this case, the space factor of the metal fiber structure 34 at the bonding interface between the surface of the heat transfer portion 20 and the protrusions 30 is preferably within a range of 40% to 80%. A space factor of the metal fiber structure 34 of 40% or more can improve the heat transfer between the surface of the heat transfer portion 20 and the protrusions 30. A space factor of the metal fiber structure 34 of 80% or less can prevent the metal fiber structure 34 from being excessively compressed.

[0022] In this heat transfer body 10a, similarly to the heat transfer body 10 shown in FIGS. 1 and 2, the strength of the protruding portion 30 can be increased and a sufficient heat transfer effect can be obtained.

[0023] Furthermore, since the metal fiber structure 34 of each protrusion 30 is fused to the heat transfer portion 20, the bonding strength between each protrusion 30 and the heat transfer portion 20 can be increased.

[0024] 4 is a longitudinal cross-sectional view showing yet another example of the configuration of the protrusions and heat transfer portions of the heat transfer body. In describing the heat transfer body 10b shown in FIG. 4, the same components as those in the heat transfer body 10 shown in FIGS. 1 and 2 will be assigned the same reference numerals and their description will be omitted.

[0025] 1 and 2, in the heat transfer body 10b shown in Fig. 4, instead of the protrusions 30 being attached to the heat transfer section 20 with adhesive 36, the core material 32 is exposed near the lower end of the protrusions 30, and the exposed portion of the core material 32 (the portion indicated by reference symbol 32a in Fig. 4) is fused to the heat transfer section 20. In this heat transfer body 10b, as in the heat transfer body 10 shown in Figs. 1 and 2, the strength of the protrusions 30 can be increased and a sufficient heat transfer effect can be obtained.

[0026] Furthermore, since the core material 32 of each protrusion 30 is fused to the heat transfer portion 20, the bonding strength between each protrusion 30 and the heat transfer portion 20 can be increased.

[0027] Fig. 5 is a longitudinal cross-sectional view showing yet another example of the configuration of the protrusions and heat transfer portions of the heat transfer body. In describing the heat transfer body 10c shown in Fig. 5, the same components as those in the heat transfer body 10 shown in Figs. 1 and 2 are designated by the same reference numerals, and their description will be omitted. Fig. 8 is a photograph of the heat transfer body 10c shown in Fig. 1 cut along the longitudinal cross-sectional view shown in Fig. 5. This photograph was taken using a scanning electron microscope (SEM) manufactured by Nikon Corporation.

[0028] In the heat transfer element 10c shown in FIG. 5, the heat transfer section 20a is composed of multiple layers of metal fiber sheets, including a first layer 22 (surface layer) and a second layer 24, as compared with the heat transfer element 10 shown in FIGS. 1 and 2. Metal-coated fibers may be used as the metal fibers contained in such a metal fiber sheet. The metal fibers contained in the metal fiber sheet are at least one of wet or dry nonwoven fabrics, woven fabrics, and meshes. Preferably, the metal fiber sheet is a metal fiber nonwoven fabric in which the metal fibers are bonded together. Specific examples of metals constituting the metal fibers contained in the metal fiber sheet include, but are not limited to, metals selected from the group consisting of stainless steel, iron, copper, aluminum, bronze, brass, nickel, and chromium, or precious metals selected from the group consisting of gold, platinum, silver, palladium, rhodium, iridium, ruthenium, and osmium. Among these, copper fibers and aluminum fibers are preferred because they have excellent thermal conductivity and a good balance between rigidity and plastic deformability. In this specification, the metal fiber sheet of the first layer 22 constitutes a second metal fiber structure in the claims.

[0029] In the heat transfer element 10c shown in FIG. 5, the metal fiber structure 34 of the protrusions 30 is attached to the heat transfer element 20 with an adhesive 36 that permeates the metal fiber sheet of the first layer 22 of the heat transfer element 20a. When attaching the metal fiber structure 34 of the protrusions 30 to the heat transfer element 20, the metal fiber structure 34 is compressed between the core material 32 and the heat transfer element 20 at the location indicated by reference symbol 34a, thereby increasing the space factor of the metal fiber structure 34. In this case, the space factor of the metal fiber structure 34 at the bonding interface between the surface of the heat transfer element 20 and the protrusions 30 is preferably within a range of 40% to 80%. A space factor of the metal fiber structure 34 of 40% or more can improve the heat transfer between the surface of the heat transfer element 20 and the protrusions 30. A space factor of the metal fiber structure 34 of 80% or less can prevent the metal fiber structure 34 from being excessively compressed.

[0030] 1 and 2, the heat transfer body 10c shown in FIG. 5 can increase the strength of the protrusions 30 and also obtain a sufficient heat transfer effect.

[0031] Furthermore, since the metal fiber structure 34 of the protrusion 30 is adhered to the heat transfer portion 20a by the adhesive 36 that has permeated the metal fiber sheet of the first layer 22 of the heat transfer portion 20a, the bonding strength between each protrusion 30 and the heat transfer portion 20a can be increased.

[0032] FIG. 6 is a cross-sectional view showing another example of the configuration of a cylindrical protrusion of a heat transfer material. The protrusion 40 shown in FIG. 6 is a rod-shaped protrusion in which annular metal fiber structures 44, 48 and another bulk material 46 made of metal are alternately fused to the periphery of a core material 42 made of a bulk metal in multiple layers. Specifically, the metal fiber structure 44 is fused to the periphery of the core material 42, and another bulk material 46 is fused to the periphery of this metal fiber structure 44. The metal fiber structure 48 is fused to the periphery of this another bulk material 46, and this metal fiber structure 48 is exposed. A heat transfer material having such protrusions 40 can also have increased strength of the protrusions 40 and obtain sufficient heat transfer effect, similar to the heat transfer material 10 shown in FIGS. 1 and 2. More specifically, the strength of the protrusions 40 can be increased by using a core material 42 made of a bulk metal. Furthermore, since the metal fiber structure 48 is exposed, the surface area of ​​the protrusions 30 can be increased, and turbulence is generated in the fluid flowing around the protrusions 40. This improves the heat transfer properties of the protrusions 40, and the heat transfer body can achieve a sufficient heat transfer effect.

[0033] Although the protrusions 30 are rod-shaped in the above description, the present embodiment is not limited to this. The multiple protrusions attached to the surface of the heat transfer part 20 may be plate-shaped and extend parallel to each other. [Example]

[0034] The present invention will be described in more detail below using examples and comparative examples.

[0035] To evaluate the thermal conductivity of the heat transfer materials according to the examples and comparative examples, a heat exchanger 100 shown in FIGS. 9 and 10 was fabricated. In the heat exchanger 100 shown in FIGS. 9 and 10, water is supplied from an inlet 104 to a region 110 between a pair of plate-like members 102. The water passes through the region between the pair of plate-like members 102 and is discharged to the outside through an outlet 106. The region 110 formed between each plate-like member 102 is a rectangular parallelepiped space measuring 10 cm in length, 10 cm in width, and 1.5 cm in height. Furthermore, 990 cylindrical rod-like members 112, each with an outer diameter of 2 mm and a height of 15 mm, are provided in this region 110. Both ends of each rod-like member 112 are attached to a corresponding plate-like member 120, and each rod-like member 112 is positioned at each intersection of the grid lines so as to extend perpendicular to each plate-like member 102. The distance between each rod-like member 112 is 3 mm. Water supplied to the region 110 from the inlet 104 passes between the rod-shaped members 112 and is discharged from the outlet 106 .

[0036] In such a heat exchanger 100, a heater 108 measuring 10 cm square was installed on one of the plate-like members 102. The power density of the heater 108 was 3.2 W / cm 2 Water was supplied to region 110 from inlet 104 at 0.5 L / min, and the water in region 110 was heated by heater 108 and then discharged from outlet 106. Using this heat exchanger 100, the thermal conductivity of rod-shaped members 112 shown in Examples 1 to 8 and Comparative Examples 1 and 2 below was measured.

[0037] Example 1 In the heat exchanger 100 according to Example 1, each rod-shaped member 112 had a cylindrical core made of a copper bulk and a metal fiber structure made of copper fibers fused to the periphery of the core, as shown in FIG. 4 , and the core was fused to the plate-shaped member 102. Here, the diameter of the core was 2 mm, and the thickness of the metal fiber structure fused to the periphery of the core was 0.1 mm. The ratio of the contact area of ​​the metal fiber structure to the area of ​​the outer circumferential surface of the core at the joint interface between the core and the metal fiber structure was 50%. The space factor of the copper fibers in the metal fiber structure was 54%. The presence rate of the metal fibers in the cross section when the metal fiber structure was cut was 55%. The space factor of the metal fiber structure at the joint surface between the surface of the plate-shaped member 102 and the rod-shaped member 112 was 53%.

[0038] <Example 2> In the heat exchanger 100 according to Example 2, each rod-shaped member 112 had a cylindrical core made of copper bulk and a metal fiber structure made of copper fibers fused to the periphery of the core, as shown in FIG. 4 , and the core was fused to the plate-shaped member 102. The diameter of the core was 2 mm, and the thickness of the metal fiber structure fused to the periphery of the core was 0.1 mm. When fusing the metal fiber structure to the periphery of the core, nanosilver particles were first coated on the outer surface of the core, and then the metal fiber structure was fused. In this rod-shaped member 112, the ratio of the contact area of ​​the metal fiber structure to the area of ​​the outer surface of the core at the bonding interface between the core and the metal fiber structure was 77%. The space factor of the copper fibers in the metal fiber structure was 56%. The metal fiber presence rate in the cross section of the metal fiber structure when cut was 68%. Furthermore, the space factor of the metal fiber structure on the joint surface between the surface of the plate-like member 102 and the rod-like member 112 was 78%.

[0039] Example 3 In the heat exchanger 100 according to Example 3, each rod-shaped member 112 had a cylindrical core made of copper bulk and a metal fiber structure made of copper fibers fused to the periphery of the core, as shown in FIG. 4 , and the core was fused to the plate-shaped member 102. Here, the diameter of the core was 2 mm, and the thickness of the metal fiber structure fused to the periphery of the core was 0.1 mm. The ratio of the contact area of ​​the metal fiber structure to the area of ​​the outer circumferential surface of the core at the joint interface between the core and the metal fiber structure was 72%. The space factor of the copper fibers in the metal fiber structure was 79%. The presence rate of the metal fibers in the cross section when the metal fiber structure was cut was 76%. The space factor of the metal fiber structure at the joint surface between the surface of the plate-shaped member 102 and the rod-shaped member 112 was 74%.

[0040] Example 4 In the heat exchanger 100 according to Example 4, each rod-shaped member 112 had a cylindrical core made of a copper bulk and a metal fiber structure made of copper fibers fused to the periphery of the core, as shown in FIG. 3 , and the metal fiber structure was fused to the plate-shaped member 102. Here, the diameter of the core was 2 mm, and the thickness of the metal fiber structure fused to the periphery of the core was 0.1 mm. The ratio of the contact area of ​​the metal fiber structure to the area of ​​the outer circumferential surface of the core at the joint interface between the core and the metal fiber structure was 23%. The space factor of the copper fibers in the metal fiber structure was 32%. The presence rate of the metal fibers in the cross section when the metal fiber structure was cut was 34%. The space factor of the metal fiber structure at the joint surface between the surface of the plate-shaped member 102 and the rod-shaped member 112 was 41%.

[0041] <Example 5> In the heat exchanger 100 according to Example 5, each rod-shaped member 112 had a cylindrical core made of copper bulk and a metal fiber structure made of copper fibers fused to the periphery of the core, as shown in FIG. 2 , and the metal fiber structure was fused to the plate-shaped member 102 with an adhesive containing nanosilver particles. Here, the diameter of the core was 2 mm, and the thickness of the metal fiber structure fused to the periphery of the core was 0.1 mm. The ratio of the contact area of ​​the metal fiber structure to the area of ​​the outer circumferential surface of the core at the joint interface between the core and the metal fiber structure was 40%. The space factor of the copper fibers in the metal fiber structure was 42%. The presence rate of the metal fibers in the cross section when the metal fiber structure was cut was 42%. The space factor of the metal fiber structure at the joint surface between the surface of the plate-shaped member 102 and the rod-shaped member 112 was 41%.

[0042] Example 6 In the heat exchanger 100 according to Example 6, each rod-shaped member 112 had a cylindrical core made of a copper bulk and a metal fiber structure made of copper fibers fused to the periphery of the core, as shown in FIG. 4 , and the core was fused to the plate-shaped member 102. Here, the diameter of the core was 2 mm, and the thickness of the metal fiber structure fused to the periphery of the core was 0.1 mm. In such a rod-shaped member 112, the ratio of the contact area of ​​the metal fiber structure to the area of ​​the outer circumferential surface of the core at the joint interface between the core and the metal fiber structure was 61%. The space factor of the copper fibers in the metal fiber structure was 61%. The presence rate of the metal fibers in the cross section when the metal fiber structure was cut was 63%. The space factor of the metal fiber structure at the joint surface between the surface of the plate-shaped member 102 and the rod-shaped member 112 was 62%.

[0043] Example 7 In the heat exchanger 100 according to Example 7, each rod-shaped member 112 had a cylindrical core made of copper bulk and a metal fiber structure made of copper fibers fused to the periphery of the core, as shown in FIG. 3 , and the metal fiber structure was fused to the plate-shaped member 102. Here, the diameter of the core was 2 mm, and the thickness of the metal fiber structure fused to the periphery of the core was 0.1 mm. When the metal fiber structure 34 was fused to the plate-shaped member 102, the metal fiber structure between the core and the plate-shaped member 102 was compressed to increase the space factor of the metal fiber structure. In this rod-shaped member 112, the ratio of the contact area of ​​the metal fiber structure to the area of ​​the outer circumferential surface of the core at the bonding interface between the core and the metal fiber structure was 21%. The space factor of the copper fibers in the metal fiber structure was 32%. The metal fiber presence rate in the cross section of the metal fiber structure when cut was 33%. Moreover, the space factor of the metal fiber structure on the joint surface between the surface of the plate-like member 102 and the rod-like member 112 was 73%.

[0044] Example 8 In the heat exchanger 100 according to Example 8, each rod-shaped member 112 had a cylindrical core made of copper bulk and a metal fiber structure made of copper fibers fused to the periphery of the core, as shown in FIG. 3 , and the metal fiber structure was fused to the plate-shaped member 102. Here, the diameter of the core was 2 mm, and the thickness of the metal fiber structure fused to the periphery of the core was 0.1 mm. When the metal fiber structure 34 was fused to the plate-shaped member 102, the metal fiber structure between the core and the plate-shaped member 102 was compressed to increase the space factor of the metal fiber structure. In this rod-shaped member 112, the ratio of the contact area of ​​the metal fiber structure to the area of ​​the outer circumferential surface of the core at the bonding interface between the core and the metal fiber structure was 55%. The space factor of the copper fibers in the metal fiber structure was 58%. The metal fiber presence rate in the cross section of the metal fiber structure when cut was 57%. Furthermore, the space factor of the metal fiber structure on the joint surface between the surface of the plate-like member 102 and the rod-like member 112 was 72%.

[0045] <Comparative Example 1> In the heat exchanger 100 according to Comparative Example 1, each rod-shaped member 112 was made of a cylindrical metal fiber structure made of copper fibers. The diameter of such a metal fiber structure was 2.1 mm. In such a rod-shaped member 112, the space factor of the copper fibers in the metal fiber structure was 54%. Furthermore, the presence rate of the metal fibers in the cross section when the metal fiber structure was cut was 54%. Furthermore, the space factor of the metal fiber structure in the joint surface between the surface of the plate-shaped member 102 and the rod-shaped member 112 was 53%.

[0046] <Comparative Example 2> In the heat exchanger 100 according to Comparative Example 2, each rod-shaped member 112 was made of a cylindrical core material made of bulk copper. The diameter of the core material was 2.0 mm. In such rod-shaped members 112, the space factor of the rod-shaped members 112 at the joint surface between the surface of the plate-shaped member 102 and the rod-shaped member 112 was 100%.

[0047] <Evaluation> The breaking strength of each rod-shaped member 112 and the thermal conductivity of the heat exchanger 100 were measured for the heat exchangers 100 having the rod-shaped members 112 according to Examples 1 to 8 and Comparative Examples 1 and 2. The measurement results are shown in Tables 1 and 2 below.

[0048] [Table 1]

[0049] [Table 2]

[0050] The rod-shaped members 112 according to Examples 1 to 10 have a breaking strength of 200 N / mm 2 The breaking strength was as high as or higher, and sufficient breaking strength was maintained, whereas the breaking strength of the rod-shaped member 112 according to Comparative Example 1 was 35 N / mm 2 , which resulted in poor strength of the rod-shaped members 112. Furthermore, the heat exchangers 100 having the rod-shaped members 112 according to Examples 1 to 10 had a thermal conductivity of 6,000 W / m 2·k, which was a higher thermal conductivity than the heat exchangers 100 having the rod-shaped members 112 according to Comparative Examples 1 and 2. Thus, it was found that the heat exchangers 100 having the rod-shaped members 112 according to Examples 1 to 10 can achieve a sufficient heat transfer effect.

Claims

1. a heat transfer portion including a metal; a protrusion attached to a surface of the heat transfer portion and extending from the heat transfer portion; Equipped with the protruding portion has a core material made of a bulk metal and a first metal fiber structure fused to the periphery of the core material, A heat transfer body, wherein the heat transfer portion has a surface layer including a second metal fiber structure, and the protrusions are attached to a surface of the surface layer.

2. The heat transfer element according to claim 1 , wherein one end of said protrusion is adhered or fused to said heat transfer portion with an adhesive material containing a metal paste.

3. The heat transfer element of claim 1 , wherein the first metal fiber structure of the protrusion is fused to the heat transfer portion.

4. The heat transfer element according to claim 1 , wherein the core material of the protrusion is fused to the heat transfer portion.

5. 5. The heat transfer body according to claim 1, wherein the ratio of the contact area of ​​the first metal fiber structure to the area of ​​the outer surface of the core material at the joint interface between the core material of the protrusion and the first metal fiber structure is within the range of 20% to 80%.

6. The heat transfer element according to claim 1 , wherein the space factor of the metal fibers in the first metal fiber structure is in the range of 30% to 80%.

7. The heat transfer element according to claim 1 , wherein the metal fiber content in a cross section of the first metal fiber structure is in the range of 30% to 80%.

8. 4. The heat transfer element according to claim 2, wherein the space factor of the first metal fiber structure at the bonding interface between the surface of the heat transfer portion and the protrusion is within a range of 40% to 80%.

9. The heat transfer element according to claim 1 , wherein the protrusions are rod-shaped or plate-shaped.

10. A heat transfer body as described in any one of claims 1 to 8, wherein the protrusion is rod-shaped and is formed by fusion bonding an annular first metal fiber structure and another bulk body made of metal to the core material in alternating multiple layers.

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