WO2023189017A1

WO2023189017A1 - Temperature adjustment unit and bonding member

Info

Publication number: WO2023189017A1
Application number: PCT/JP2023/006181
Authority: WO
Inventors: 英輝森内
Original assignee: 株式会社巴川製紙所
Priority date: 2022-03-31
Filing date: 2023-02-21
Publication date: 2023-10-05
Also published as: TW202403258A

Abstract

A temperature adjustment unit (10) is provided with a heat transfer portion (for example, a bar-like member (40)), a base material (20), and a bonding member (30) for attaching the heat transfer portion to the base material. The bonding member (30) is composed of a plurality of metal particles (for example, silver particles (30b)) having a primary particle size of less than 100 nm, and a metal melt (30a), wherein the proportion of the area occupied by the metal particles to the proportion occupied by the bonding member (30) is in the range of 0.5-0.9.

Description

Temperature control unit and joining parts

The present invention relates to a temperature control unit and a joining member.

Conventionally, temperature control units have been used in electrical equipment, electronic equipment, semiconductor equipment, etc. to protect circuits etc. that are susceptible to heat generation. More specifically, as the amount of power used by electrical equipment increases, the amount of heat generated also increases, so the temperature inside the electrical equipment has been adjusted by cooling the generated heat with a temperature control unit. As an example of a temperature control unit, one is known that is formed by attaching a plurality of rod-like members to a flat base material so as to extend in parallel at intervals.

For example, those disclosed in Patent Documents 1 and 2 are known as joining members used when attaching a plurality of rod-shaped members to a base material. Japanese Patent Publication No. 10-106722 (JPH10-106722A) discloses a technique for bonding a porous body and other materials using a paste-like bonding silver conductor. In addition, Japanese Patent Publication No. 2003-240473 (JP2003-240473A) discloses a heat exchanger that satisfactorily joins a metal porous member and a metal flat plate to significantly increase heat exchange efficiency. has been done.

Conventional bonding members were generally composed of a molten metal body formed by melting and fixing metal particles. However, when the heat transfer part is attached to the base material using such a joining member, when the base material expands or contracts due to heat, the joining member may follow the expansion or contraction of the base material. Otherwise, there was a risk of warping, peeling, cracking, etc.

The present invention has been made with these points in mind, and it is possible for the joining member to follow the expansion and contraction of the base material, and also to maintain sufficient strength and heat between the base material and the heat transfer part. It is an object of the present invention to provide a temperature control unit and a joining member that can obtain conductivity.

The temperature control unit of the present invention includes:
a heat transfer part;
base material and
a joining member for attaching the heat transfer part to the base material;
Equipped with
The joining member is composed of a plurality of metal particles having a primary particle size of less than 100 nm and a metal melt,
It is characterized in that the ratio of the area occupied by the metal particles to the ratio occupied by the joining member in the cross section of the joining member is within the range of 0.5 to 0.9.

In the temperature control unit of the present invention,
The ratio of the area occupied by the metal particles to the ratio occupied by the joining member in the cross section of the joining member may be within the range of 0.55 to 0.85.

In the temperature control unit of the present invention,
In the cross section of the portion where the heat transfer part is attached to the base material, the ratio of the length of the portion where the joining member is attached to the base material to the length of the surface of the base material is 0.25 or more, Good too.

In the temperature control unit of the present invention,
The material of the joining member may include silver or a silver alloy.

In the temperature control unit of the present invention,
The heat transfer section may have a rod-like member or a plate-like member including a metal fiber structure.

In the temperature control unit of the present invention,
The base material may include metal, glass, or ceramic.

The joining member of the present invention is
A joining member for attaching a heat transfer part to a base material,
Consisting of a plurality of metal particles with a primary particle size of less than 100 nm and a metal melt,
It is characterized in that the ratio of the area occupied by the metal particles to the ratio occupied by the joining member in the cross section of the joining member is within the range of 0.5 to 0.9.

In the joining member of the present invention,
The ratio of the area occupied by the metal particles to the ratio occupied by the joining member in the cross section of the joining member may be within the range of 0.55 to 0.85.

FIG. 1 is a front view showing the configuration of a temperature control unit according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA of the temperature control unit shown in FIG. 1. FIG. FIG. 2 is a schematic configuration diagram showing a first example of a joint location between a rod-shaped member (heat transfer section) and a base material in the temperature control unit shown in FIG. 1. FIG. FIG. 2 is a schematic configuration diagram showing a second example of a joint location between a rod-shaped member (heat transfer section) and a base material in the temperature control unit shown in FIG. 1. FIG. FIG. 2 is a schematic configuration diagram showing a third example of a joint location between a rod-shaped member (heat transfer section) and a base material in the temperature control unit shown in FIG. 1. FIG. It is a schematic block diagram which shows the 4th example of the joint part of the rod-shaped member (heat transfer part) and base material in the temperature control unit shown in FIG. 2 is a schematic configuration diagram schematically showing the configuration of a rod-shaped member (heat transfer section) and a connecting member in the temperature control unit shown in FIG. 1. FIG. 2 is a configuration diagram showing the configuration of a first side wall member in the temperature control unit shown in FIG. 1. FIG. FIG. 2 is an enlarged view showing a joining member and a base material according to an embodiment of the present invention. FIG. 3 is a diagram showing metal particles constituting a joining member according to an embodiment of the present invention. FIG. 2 is an enlarged view showing a joining member and a base material mainly made of molten metal.

Embodiments of the present invention will be described below with reference to the drawings. 1 to 10 are diagrams showing a temperature control unit and a joining member according to an embodiment of the present invention. Of these, FIG. 1 is a front view showing the configuration of the temperature control unit according to the present embodiment, and FIG. 2 is a sectional view taken along the line AA of the temperature control unit shown in FIG. Further, FIGS. 3 to 6 are schematic configuration diagrams showing first to fourth examples of joint locations between the rod-shaped member (heat transfer portion) and the base material in the temperature control unit shown in FIG. 1, respectively. Further, FIG. 7 is a configuration diagram showing the configuration of a rod-shaped member (heat transfer part) and a connecting member in the temperature control unit shown in FIG. 1, and FIG. 8 is a configuration diagram showing the structure of the first side wall member in the temperature control unit shown in FIG. It is a block diagram which shows a structure. Further, FIG. 9 is an enlarged view showing the joining member and the base material according to the present embodiment, and FIG. 10 is a diagram showing metal particles constituting the joining member according to the present embodiment. Note that FIG. 11 is an enlarged view showing a joining member and a base material mainly made of molten metal.

As shown in FIGS. 1 and 2, the temperature control unit 10 according to the present embodiment includes a pair of flat base members 20, a pair of flat first side wall members 22, and a pair of flat second side wall members 22. It has a substantially rectangular parallelepiped shape with side wall members 24, and the fluid flows into the internal region 16 formed between the pair of base members 20, the pair of first side wall members 22, and the pair of second side wall members 24. It is now possible to FIG. 8 is a configuration diagram showing the configuration of the first side wall member 22. As shown in FIG. Further, one of the pair of base materials 20 is formed with a fluid inlet section 12 and a fluid outlet section 14, respectively, and this base material 20 has a fluid inlet section 12 and a fluid outlet section 14 formed therein. An opening 20p through which the fluid passes and an opening 20q through which the fluid sent from the internal region 16 to the fluid outlet section 14 passes are formed. Further, between the pair of base materials 20, a plurality of rod-shaped members 40 are arranged as heat transfer portions so as to extend in parallel to each other. Each rod-shaped member 40 has a cylindrical shape, and is arranged so as to be located at the intersection of the grids in the cross section of the temperature control unit 10 shown in FIG. The fluid that enters the internal area 16 of the temperature control unit 10 from the fluid inlet 12 through the opening 20p flows in the internal area 16 in the right direction in FIGS. 1 and 2, and is sent to the fluid outlet 14 through the opening 20q. It looks like this. The fluid flowing inside the internal region 16 includes, for example, water, air, antifreeze, organic solvents, fluorinated solvents (eg, Fluorinert, Freon), and the like.

Each base material 20 includes, for example, metal, glass, or ceramic. Examples of these metals include stainless steel, copper, nickel, aluminum, and alloys containing at least one of these. Examples of the glass include quartz glass, soda glass, and glass containing any metal oxide. Examples of the ceramic include alumina, magnesia, zirconia, aluminum nitride (AlN), silicon carbide (SiC), silicon nitride (SiN), and porous ceramics thereof.

A heater (not shown) is attached to the outer surface of the base material 20 in the temperature control unit 10, and the fluid flowing in the internal region 16 is heated by the heat transferred from the heater to each rod-shaped member 40 via the base material 20. It is now possible to Here, the temperature control unit 10 of the present embodiment includes a plurality of rod-shaped members 40 that extend parallel to each other at intervals, and a connecting member 20m (see FIGS. 3 to 6) that connects each of the rod-shaped members 40. It is formed by combining ladder-shaped structures. FIG. 7 is a schematic configuration diagram schematically showing a ladder-shaped structure composed of a plurality of rod-like members 40 and a connecting member 20m that connects each rod-like member 40. As shown in FIG. Each base material 20 is a combination of connection members 20m in a plurality of ladder-shaped structures.

Each rod-shaped member 40 includes a metal fiber structure formed from metal fibers such as copper fibers. Metal-coated fibers may be used as such metal fibers. Further, the metal fiber structure may be formed into a nonwoven fabric, woven fabric, mesh, or the like using a wet or dry manufacturing method, and then processed into a metal fiber structure. Preferably, as the metal fiber structure, a metal fiber structure in which metal fibers are integrated and then bound is used. The term "metal fibers bound together" means that the metal fibers are physically fixed to each other to form a bound portion. In the metal fiber structure, the metal fibers may be directly fixed to each other at a binding part, or some of the metal fibers may be indirectly fixed to each other via a component other than the metal component. .

In the rod-shaped member 40, since the metal fiber structure is formed from metal fibers, voids exist inside the metal fiber structure. This allows the fluid flowing through the internal region 16 to pass through the inside of the metal fiber structure of the rod-shaped member 40, making it easier to improve heat exchange performance with the fluid. Moreover, in the metal fiber structure, when the metal fibers are bound together, voids are more likely to be formed between the metal fibers constituting the metal fiber structure. Such voids may be formed, for example, by intertwining metal fibers. Further, in the metal fiber structure, it is preferable that the metal fibers are sintered at the binding portion. By sintering the metal fibers, the thermal conductivity and homogeneity of the metal fiber structure become more stable.

Although FIG. 2 shows the rod-shaped member 40 having a circular cross section, the cross-section of the rod-shaped member 40 in this embodiment is not limited to a circular shape. The cross-sectional shape of the rod-shaped member 40 may be a trapezoid, a triangle, a semicircle, or a mountain. Further, when a fluid flow path is formed between the plurality of rod-shaped members 40, the plurality of comb-shaped structures are arranged so that the flow path meander along the direction in which the fluid flows. You can. In this case, the fluid flows in a meandering manner along the flow path, so as the heat exchange area of the fluid flowing through the flow path increases, the pressure loss becomes moderately large, and the residence time of the fluid within the flow path increases. Since the length can be increased, the heat transfer effect can be enhanced.

Furthermore, a plate-like or rod-like member having no voids may be used as the heat transfer part. Examples of the material for such a plate-like or rod-like heat transfer portion having no voids include metals, and specific examples thereof include stainless steel, copper, nickel, aluminum, and alloys containing at least one of these.

Next, a method of attaching the rod-shaped member 40 to the base material 20 (specifically, each connecting member 20m that constitutes the base material 20) using the joining member 30 will be described. There are various methods for attaching the rod-shaped member 40 to the connecting member 20m using the joining member 30, as shown in FIGS. 3 to 6. As shown in FIG. 3, a joining member 30 may be attached to the upper surface of the connecting member 20m, and a rod-shaped member 40 may be attached to the upper surface of this joining member 30. Alternatively, as shown in FIG. 4, a recess may be formed in the connecting member 20m, the joining member 30 may be accommodated in the recess, and the rod-shaped member 40 may be attached to the upper surface of the joining member 30 accommodated in the recess. Further, as shown in FIG. 5, a recess may be formed in the connecting member 20m, the joining member 30 may be accommodated in the recess, and the rod-shaped member 40 may be embedded in the joining member 30 accommodated in the recess. Further, as shown in FIG. 6, the rod-shaped member 40 is arranged on the surface of the connecting member 20m, and the joining member 30 is arranged on the rod-shaped member 40 near the contact point between the connecting member 20m and the rod-shaped member 40. 40 may be joined to the connecting member 20m.

The joining member 30 has a paste containing nanosilver particles. More specifically, as shown in FIG. 9, the bonding member 30 includes a plurality of silver particles 30b having a primary particle diameter of less than 100 nm, and a metal melt formed by the silver particles 30b melting and sticking together. 30a. FIG. 10 is an enlarged view of the plurality of silver particles 30b shown in FIG. Note that the primary particle size of the silver particles 30b is determined by calculating the average value of the number of sampled particles n=100, using the average value of the long axis and short axis of the particles as the particle size in the SEM photograph. Here, in the present embodiment, in the cross section of the joining member 30, the ratio of the area b occupied by the silver particles 30b to the total area (a+b) of the area a occupied by the metal melt 30a and the area b occupied by the silver particles 30b. c (ie, the value of b/(a+b)) is within the range of 0.5 to 0.9, preferably within the range of 0.55 to 0.85. Here, such a ratio c is a predetermined distance (for example, 1 μm) from the surface 20a of the base material 20 in the cross section near the location where the rod-shaped member 40 is attached to the base material 20 (specifically, the connecting member 20m). ) (indicated by reference numeral 20a' in FIG. 9), it is calculated based on the area a occupied by the metal melt 30a and the area b occupied by the silver particles 30b. In this embodiment, since the bonding member 30 is a mixture of the metal melt 30a and the silver particles 30b, the inclusion of the silver particles 30b in the bonding member 30 causes the base material 20 to be heated by the heater attached to the base material 20. Even when the base material 20 expands, the bonding member 30 can follow the expansion of the base material 20, thereby suppressing the occurrence of warping, peeling, cracking, etc. in the bonding member 30. Further, by including the metal melt 30a in the joining member 30, the rod-shaped member 40 can be firmly joined to the base material 20, and sufficient heat transfer from the base material 20 to the rod-shaped member 40 can be obtained.

When the ratio c is smaller than 0.5 in the bonding member 30, the base material 20 expands due to the heat generated by the heater attached to the base material 20 due to too few silver particles 30b contained in the bonding member 30. The bonding member 30 may not be able to follow the expansion of the base material 20, and warping, peeling, cracking, etc. may occur. Further, if the ratio c in the joining member 30 is larger than 0.9, the rod-shaped member 40 cannot be firmly joined to the base material 20 because the molten metal 30a contained in the joining member 30 is too small. First, there is also the problem that sufficient heat conductivity from the base material 20 to the rod-shaped member 40 cannot be obtained. On the other hand, if the ratio c in the bonding member 30 is within the range of 0.5 to 0.9, these problems are suppressed.

Further, in the cross section of the portion where the rod-shaped member 40 is attached to the base material 20, the ratio d of the length of the portion where the joining member 30 is attached to the base material 20 to the length of the surface 20a of the base material 20 is 0.25 or more. , preferably 0.5 or more. In the joining member 30 as shown in FIG. 9, the ratio d is approximately 0.7. On the other hand, as shown in FIG. 11, the bonding member 30 may not adhere to the surface of the base material 20 very much, and the ratio d may be smaller than 0.25. More specifically, in FIG. 11, the base material 20 is composed of a metal plate 20c and a thermally sprayed layer 20b in which plating or the like is thermally sprayed on the surface of the metal plate 20c. , the length ratio of the portion where the joining member 30 is attached to the sprayed layer 20b (indicated by reference numeral 30c in FIG. 11) is smaller than 0.25. In this way, when the ratio d is smaller than 0.25, the bonding member 30 is likely to peel off from the base material 20, and therefore, for example, when the base material 20 expands and contracts, the bonding member 30 peels off from the base material 20 and the rod-shaped member 40 is spaced apart from the base material 20, there is a possibility that thermal conductivity will be significantly reduced.

Next, a method of joining the rod-shaped member 40 to the connecting member 20m using the joining member 30 having such a configuration will be described. First, as shown in FIGS. 3 to 6, a silver nanopaste is applied between the connecting member 20m and the rod-shaped member 40, and then a temperature difference is applied between the connecting member 20m and the rod-shaped member 40, and the silver nanopaste is applied between the connecting member 20m and the rod-shaped member 40. Some of the silver particles contained in the paste are sintered. As a method of creating a temperature difference between the connecting member 20m and the rod-shaped member 40, for example, the connecting member 20m is cooled by a Peltier element, a ceramic heater is brought into contact with the rod-shaped member 40, and the silver is heated by heat conduction through the rod-shaped member 40. Sinter some of the particles. Thermal gradient conditions vary depending on the particle size of the silver particles and the melting point of the material, but when using silver particles with an average particle size (hydrodynamic particle size) of 10 nm using the dynamic light scattering method, for example, a rod-shaped When the temperature at the tip of the member 40 is 250 to 300°C, the temperature at the joint between the connecting member 20m and the rod-shaped member 40 is adjusted to 150 to 200°C, and by heating in a nitrogen atmosphere for 30 to 120 minutes. , a nanoparticle structure can be obtained by sintering the nanoparticles at this junction.

According to the temperature control unit 10 and the joining member 30 of the present embodiment having the above-described configuration, the joining member 30 has a plurality of metal particles (specifically, silver particles) having a primary particle size smaller than 100 nm. 30b) and a molten metal 30a, and the ratio of the area occupied by the metal particles to the ratio occupied by the bonding member 30 is within the range of 0.5 to 0.9, so that the expansion of the base material 20 The joining member 30 can follow the shrinkage and contraction, and sufficient strength retention and thermal conductivity can be obtained between the base material 20 and the heat transfer portion (specifically, the rod-shaped member 40). Note that the ratio of the area occupied by the metal particles (specifically, the silver particles 30b) to the ratio occupied by the bonding member 30 is preferably within the range of 0.55 to 0.85. In this case, the joining member 30 can further follow the expansion and contraction of the base material 20, and sufficient strength retention and thermal conductivity can be obtained between the base material 20 and the heat transfer section.

Furthermore, in the temperature control unit 10 and the joining member 30 of the present embodiment, the length of the surface of the base material 20 is It is preferable that the ratio of the length of the part where the joining member 30 is attached to the base material 20 to the length is 0.25 or more. In this case, even if the base material 20 expands or contracts, it is possible to prevent the bonding member 30 from peeling off from the base material 20, so that there is sufficient space between the base material 20 and the heat transfer section. It is possible to obtain good strength retention and thermal conductivity.

Furthermore, in the temperature control unit 10 and the joining member 30 of this embodiment, the material of the joining member 30 contains silver. Note that the material of the joining member 30 is not limited to silver. A silver alloy may be used as another material for the joining member 30. Furthermore, other materials for the joining member 30 may include copper, nickel, and the like.

Furthermore, in the temperature control unit 10 of this embodiment, the heat transfer section (specifically, the rod-shaped member 40) includes a metal fiber structure. In this case, the fluid flowing inside the temperature control unit 10 can pass through the inside of the metal fiber structure of the heat transfer section. This makes it easier to improve heat exchange performance with the fluid. Further, a plate-like member may be used as the heat transfer portion.

Furthermore, in the temperature control unit 10 of this embodiment, the base material 20 includes metal, glass, or ceramic. In this case, even if the base material 20 is expanded by a heater attached to the base material 20, for example, the joining member 30 having the above-mentioned configuration can follow the expansion of the base material 20, so that the joining can be performed. It is possible to suppress the occurrence of warping, peeling, cracking, etc. in the member 30.

Note that the temperature control unit according to this embodiment is not limited to the above-described embodiment. Various other examples of the temperature control unit according to this embodiment will be described below.

For example, the above ratio c is within a predetermined distance (for example, 1 μm) from the surface 20a of the base material 20 in the cross section near the location where the rod-shaped member 40 is attached to the base material 20 (reference numeral 20a' in FIG. 9). It is not limited to calculation based on the area a occupied by the metal melt 30a and the area b occupied by the silver particles 30b in the area within the range (displayed). As another example, the ratio c may be calculated based on the area a occupied by the metal melt 30a and the area b occupied by the silver particles 30b in the entire area of the cross section of the joining member 30.

Hereinafter, the present invention will be explained in more detail using Examples and Comparative Examples.

<First example>
A temperature control unit having a shape as shown in FIGS. 1 and 2 was created. At this time, as shown in FIG. 3, a joining member was attached to the upper surface of the connecting member, and a rod-shaped member was attached to the upper surface of this joining member. Then, a temperature control unit was manufactured by combining a comb-shaped structure composed of a plurality of rod-shaped members extending parallel to each other at intervals and one connecting member connecting the rod-shaped members. At this time, the area of the base material to which the rod-shaped member was attached was 100 cm ² . Further, each rod-shaped member included a metal fiber structure made of copper fibers, and the space factor of the copper fibers was 51%. In addition, when joining the rod-shaped member to the connecting member using the joining member, silver nanopaste with a particle size of 6 nm is applied between the connecting member and the rod-shaped member, and then there is a temperature difference between the connecting member and the rod-shaped member. was applied to sinter some of the silver particles contained in the silver nanopaste. Specifically, the connecting member was cooled by a Peltier element, a ceramic heater was brought into contact with the rod-shaped member, the temperature at the tip of the rod-shaped member was 271°C, and the temperature at the joint between the rod-shaped member and the connecting member was 165°C for 60 minutes. By maintaining the temperature, some of the silver particles were sintered by heat conduction through the rod-shaped member. In the temperature control unit according to the first embodiment, the area a occupied by the molten metal and the area occupied by the silver particles in the area within 1 μm from the surface of the base material in the cross section near the location where the rod-shaped member is attached to the base material. The ratio c of area b occupied by the silver particles to the total area (a+b) of area b was 79%. Further, in the cross section of the portion where the rod-shaped member is attached to the base material, the ratio d of the length of the portion where the joining member is attached to the base material to the length of the surface of the base material was 89%.

<Second example>
A temperature control unit was created by the same method as in the first example. At this time, the area of the base material to which the rod-shaped member was attached was 100 cm ² . Further, each rod-shaped member included a metal fiber structure made of copper fibers, and the space factor of the copper fibers was 50%. In addition, when joining the rod-shaped member to the connecting member using the joining member, silver nanopaste with a particle size of 6 nm is applied between the connecting member and the rod-shaped member, and then there is a temperature difference between the connecting member and the rod-shaped member. was applied to sinter some of the silver particles contained in the silver nanopaste. Specifically, the connecting member was cooled by a Peltier element, a ceramic heater was brought into contact with the rod-shaped member, the temperature at the tip of the rod-shaped member was 271°C, and the temperature at the joint between the rod-shaped member and the connecting member was 165°C for 60 minutes. By maintaining the temperature, some of the silver particles were sintered by heat conduction through the rod-shaped member. In the temperature control unit according to the second embodiment, the area a occupied by the molten metal and the area occupied by the silver particles in the area within 1 μm from the surface of the base material in the cross section near the location where the rod-shaped member is attached to the base material. The ratio c of area b occupied by the silver particles to the total area (a+b) of area b was 80%. Further, in the cross section of the portion where the rod-shaped member is attached to the base material, the ratio d of the length of the portion where the joining member is attached to the base material to the length of the surface of the base material was 31%.

<Third Example>
A temperature control unit was created by the same method as in the first example. At this time, the area of the base material to which the rod-shaped member was attached was 100 cm ² . Further, each rod-shaped member included a metal fiber structure made of copper fibers, and the space factor of the copper fibers was 52%. In addition, when joining the rod-shaped member to the connecting member using the joining member, silver nanopaste with a particle size of 6 nm is applied between the connecting member and the rod-shaped member, and then there is a temperature difference between the connecting member and the rod-shaped member. was applied to sinter some of the silver particles contained in the silver nanopaste. Specifically, the connecting member was cooled by a Peltier element, a ceramic heater was brought into contact with the rod-shaped member, the temperature at the tip of the rod-shaped member was 271°C, and the temperature at the joint between the rod-shaped member and the connecting member was 165°C for 60 minutes. By maintaining the temperature, some of the silver particles were sintered by heat conduction through the rod-shaped member. In the temperature control unit according to the third embodiment, the area a occupied by the molten metal and the area occupied by the silver particles in the area within 1 μm from the surface of the base material in the cross section near the location where the rod-shaped member is attached to the base material. The ratio c of area b occupied by the silver particles to the total area (a+b) of area b was 51%. Further, in the cross section of the portion where the rod-shaped member is attached to the base material, the ratio d of the length of the portion where the joining member is attached to the base material to the length of the surface of the base material was 92%.

<Fourth Example>
A temperature control unit was created by the same method as in the first example. At this time, the area of the base material to which the rod-shaped member was attached was 100 cm ² . Further, each rod-shaped member included a metal fiber structure made of copper fibers, and the space factor of the copper fibers was 51%. In addition, when joining the rod-shaped member to the connecting member using the joining member, silver nanopaste with a particle size of 6 nm is applied between the connecting member and the rod-shaped member, and then there is a temperature difference between the connecting member and the rod-shaped member. was applied to sinter some of the silver particles contained in the silver nanopaste. Specifically, the connecting member was cooled by a Peltier element, a ceramic heater was brought into contact with the rod-shaped member, the temperature at the tip of the rod-shaped member was 271°C, and the temperature at the joint between the rod-shaped member and the connecting member was 165°C for 60 minutes. By maintaining the temperature, some of the silver particles were sintered by heat conduction through the rod-shaped member. In the temperature control unit according to the fourth embodiment, the area a occupied by the molten metal and the area occupied by the silver particles in the area within 1 μm from the surface of the base material in the cross section near the location where the rod-shaped member is attached to the base material. The ratio c of area b occupied by the silver particles to the total area (a+b) of area b was 53%. Further, in the cross section of the portion where the rod-shaped member is attached to the base material, the ratio d of the length of the portion where the joining member is attached to the base material to the length of the surface of the base material was 29%.

<First comparative example>
A temperature control unit was created by the same method as in the first example. At this time, the area of the base material to which the rod-shaped member was attached was 100 cm ² . Further, each rod-shaped member included a metal fiber structure made of copper fibers, and the space factor of the copper fibers was 52%. In addition, when joining the rod-shaped member to the connecting member using the joining member, silver nanopaste with a particle size of 6 nm is applied between the connecting member and the rod-shaped member, and then there is a temperature difference between the connecting member and the rod-shaped member. was applied to sinter some of the silver particles contained in the silver nanopaste. Specifically, the connecting member was cooled by a Peltier element, a ceramic heater was brought into contact with the rod-shaped member, the temperature at the tip of the rod-shaped member was 271°C, and the temperature at the joint between the rod-shaped member and the connecting member was 165°C for 60 minutes. By maintaining the temperature, some of the silver particles were sintered by heat conduction through the rod-shaped member. In the temperature control unit according to the first comparative example, the area a occupied by the molten metal and the area occupied by the silver particles in the area within 1 μm from the surface of the base material in the cross section near the location where the rod-shaped member is attached to the base material. The ratio c of area b occupied by the silver particles to the total area (a+b) of area b was 47%. Further, in the cross section of the portion where the rod-shaped member is attached to the base material, the ratio d of the length of the portion where the joining member is attached to the base material to the length of the surface of the base material was 90%.

<Second comparative example>
A temperature control unit was created by the same method as in the first example. At this time, the area of the base material to which the rod-shaped member was attached was 100 cm ² . Further, each rod-shaped member included a metal fiber structure made of copper fibers, and the space factor of the copper fibers was 52%. In addition, when joining the rod-shaped member to the connecting member using the joining member, silver nanopaste with a particle size of 6 nm is applied between the connecting member and the rod-shaped member, and then there is a temperature difference between the connecting member and the rod-shaped member. was applied to sinter some of the silver particles contained in the silver nanopaste. Specifically, the connecting member was cooled by a Peltier element, a ceramic heater was brought into contact with the rod-shaped member, the temperature at the tip of the rod-shaped member was 271°C, and the temperature at the joint between the rod-shaped member and the connecting member was 165°C for 60 minutes. By maintaining the temperature, some of the silver particles were sintered by heat conduction through the rod-shaped member. In the temperature control unit according to the second comparative example, the area a occupied by the molten metal and the area occupied by the silver particles in the area within 1 μm from the surface of the base material in the cross section near the location where the rod-shaped member is attached to the base material. The ratio c of area b occupied by the silver particles to the total area (a+b) of area b was 46%. Further, in the cross section of the part where the rod-shaped member is attached to the base material, the ratio d of the length of the part where the joining member is attached to the base material to the length of the surface of the base material was 21%.

<Third comparative example>
A temperature control unit was created by the same method as in the first example. At this time, the area of the base material to which the rod-shaped member was attached was 100 cm ² . Further, each rod-shaped member included a metal fiber structure made of copper fibers, and the space factor of the copper fibers was 51%. In addition, when joining the rod-shaped member to the connecting member using the joining member, silver nanopaste with a particle size of 6 nm is applied between the connecting member and the rod-shaped member, and then there is a temperature difference between the connecting member and the rod-shaped member. was applied to sinter all the silver particles contained in the silver nanopaste. Specifically, the connecting member was cooled by a Peltier element, a ceramic heater was brought into contact with the rod-shaped member, the temperature at the tip of the rod-shaped member was 271°C, and the temperature at the joint between the rod-shaped member and the connecting member was 165°C for 60 minutes. By maintaining the temperature, all the silver particles were sintered by heat conduction through the rod-shaped member. In the temperature control unit according to the third comparative example, the area a occupied by the molten metal and the area occupied by the silver particles in the area within 1 μm from the surface of the base material in the cross section near the location where the rod-shaped member is attached to the base material. The ratio c of area b occupied by the silver particles to the total area (a+b) of area b was 0%. That is, the silver particles were completely sintered into a metal melt. Further, in the cross section of the portion where the rod-shaped member is attached to the base material, the ratio d of the length of the portion where the joining member is attached to the base material to the length of the surface of the base material was 62%.

<Fourth comparative example>
A temperature control unit was created by the same method as in the first example. At this time, the area of the base material to which the rod-shaped member was attached was 100 cm ² . Further, each rod-shaped member included a metal fiber structure made of copper fibers, and the space factor of the copper fibers was 51%. In addition, when joining the rod-shaped member to the connecting member using the joining member, silver nanopaste with a particle size of 6 nm is applied between the connecting member and the rod-shaped member, and then there is a temperature difference between the connecting member and the rod-shaped member. was applied to sinter some of the silver particles contained in the silver nanopaste. Specifically, the connecting member was cooled by a Peltier element, a ceramic heater was brought into contact with the rod-shaped member, the temperature at the tip of the rod-shaped member was 271°C, and the temperature at the joint between the rod-shaped member and the connecting member was 165°C for 60 minutes. By maintaining the temperature, some of the silver particles were sintered by heat conduction through the rod-shaped member. In the temperature control unit according to the fourth comparative example, the area a occupied by the molten metal and the area occupied by the silver particles in the area within 1 μm from the surface of the base material in the cross section near the location where the rod-shaped member is attached to the base material. The ratio c of area b occupied by the silver particles to the total area (a+b) of area b was 98%. That is, the silver particles were hardly melted and occupied most of the bonding member. Further, in the cross section of the portion where the rod-shaped member is attached to the base material, the ratio d of the length of the portion where the joining member is attached to the base material to the length of the surface of the base material was 52%.

<Evaluation>
The heat transfer coefficients before and after the thermal shock test were calculated for the temperature control units according to the first to fourth examples and the temperature control units according to the first to fourth comparative examples, and changes in the heat transfer coefficients were determined. . The method for calculating the heat transfer coefficient is to pass ethylene glycol as a refrigerant at a temperature of 25°C through the evaluation unit, apply 100W of heat input from the heater, and connect the liquid inlet (IN side) and exhaust of the evaluation unit. The fluid temperature near the outlet (OUT side) and the contact temperature between the heater and the evaluation unit were measured, and the heat transfer coefficient and thermal resistance were calculated. Specifically, the amount of heat input from the heater to the fluid W, the transfer area S of the fluid passing portion adjacent to the heater, the surface temperature Ts of the casing of the evaluation unit near the heater, the average temperature Tw of the passing fluid (the fluid inlet temperature and the average value of the outlet temperature), and calculate the heat transfer coefficient h (W/m ² ×K) from the formula: heat input W = heat transfer coefficient h × transfer area S × (surface temperature Ts - fluid average temperature Tw) I asked for it.

In addition, the thermal conductivity was calculated before and after the thermal shock test. In the thermal shock test, the evaluation unit is placed in a highly accelerated thermal shock device made by Espec, and the bonded members are subjected to thermal shock by continuously applying temperature changes from -40°C to 120°C and from 120°C to -40°C. Ta. The temperature return time to -40°C and 120°C was 10 minutes, the holding time at each temperature was 30 seconds, and the number of cycles was 1,000 times.

The measurement results of the thermal conductivity calculated in this way are shown in Table 1 below. In making a judgment about the change in heat transfer coefficient, the difference between the thermal conductivity measured before the thermal conductivity and the thermal conductivity measured after the thermal shock test is calculated as follows: Very good when the rate of change, which is the value divided by thermal conductivity, is 5% or less, good when it is greater than 5% and less than 20%, and poor when it is greater than 20%. bad). The smaller this rate of change is, the less there is a change in thermal conductivity before and after the thermal shock test, and the more the bond between the base material and the rod-shaped member is It can be said that no problems have occurred.

As shown in Table 1 above, the temperature control units according to Examples 1 to 4 can be used for a long period of time because there is not much change in thermal conductivity before and after the thermal shock test, and the strength of the bonded members is sufficient. It is considered that no major problem will occur in the bonding between the base material and the rod-shaped member even if the base material and the rod-shaped member are bonded to each other. On the other hand, in the temperature control units according to the first to fourth comparative examples, the thermal conductivity changes significantly before and after the thermal shock test, and the strength of the joint member is not sufficient, so if used for a long period of time, the base material and the rod-shaped member It is thought that there is a possibility that the bond between the two parts may not be sufficient.

Claims

a heat transfer part;
base material and
a joining member for attaching the heat transfer part to the base material;
Equipped with
The joining member is composed of a plurality of metal particles having a primary particle size of less than 100 nm and a metal melt,
A temperature control unit, wherein the ratio of the area occupied by the metal particles to the ratio occupied by the joining member in the cross section of the joining member is within the range of 0.5 to 0.9.
The temperature control unit according to claim 1, wherein the ratio of the area occupied by the metal particles to the ratio occupied by the joining member in the cross section of the joining member is within the range of 0.55 to 0.85.
In a cross section of a location where the heat transfer part is attached to the base material, a ratio of the length of the location where the bonding member is attached to the base material to the length of the surface of the base material is 0.25 or more; The temperature control unit according to claim 1 or 2.
The temperature control unit according to any one of claims 1 to 3, wherein the material of the joining member includes silver or a silver alloy.
The temperature control unit according to any one of claims 1 to 4, wherein the heat transfer section has a rod-like member or a plate-like member containing a metal fiber structure.
The temperature control unit according to any one of claims 1 to 5, wherein the base material includes metal, glass, or ceramic.
A joining member for attaching a heat transfer part to a base material,
Consisting of a plurality of metal particles with a primary particle size of less than 100 nm and a metal melt,
A joining member, wherein the ratio of the area occupied by the metal particles to the ratio occupied by the joining member in a cross section of the joining member is within the range of 0.5 to 0.9.
The joining member according to claim 7, wherein the ratio of the area occupied by the metal particles to the ratio occupied by the joining member in the cross section of the joining member is within the range of 0.55 to 0.85.