JP2015026787A - Cooling member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling member easy to fabricate, and superior in durability and heat dissipation effect.SOLUTION: A cooling member comprises: a base material; a metal layer deposited on the base material, and including a nitrogen (N)-containing nickel (Ni) alloy, and at least one of pure metals of gold (Au), silver (Ag), copper (Cu), platinum (Pt) and palladium (Pd), and alloys thereof; and a porous layer 8 formed by applying plasma to a surface of the metal layer while supplying nitrogen thereto.

Description

  The present invention relates to a cooling member that is attached in contact with various devices that are objects to be cooled and that absorbs heat from the device.

  Conventionally, various cooling members are used to maintain the operation performance and reliability of various devices. As such a thing, there exists a cooling member shown in patent document 1, for example. This document describes a cooling member used in a direct methanol fuel cell. According to the description in the literature, when the membrane electrode assembly of a direct methanol fuel cell is cooled, the cooling effect is not sufficient only by thermal diffusion with a simple metal plate, and the cooling member is formed by water generated on the air electrode. There is also a disadvantage that the air permeability of the water is hindered.

  As a solution to this problem, Patent Document 1 discloses a technique using a metal porous sintered body having a skeleton obtained by sintering a metal powder around pores as a cooling member. . As a result, it is described that the liquid is absorbed into the pores of the metal porous crystal by capillary action, the absorbed liquid is efficiently evaporated and the heat of evaporation is taken away from the surroundings, and as a result, a good cooling effect is exhibited. ing.

JP 2006-313648 A

The cooling member of the known document 1 is not a simple sintered structure, but has a skeleton obtained by sintering metal powder around the pores. For example, pores having an average pore diameter of 200 μm or less are formed in a skeleton portion formed by aggregating metal powders, and pores having an average diameter of about 3000 μm are formed by the skeleton portion. However, it is very difficult to form such a complicated metal structure uniformly. For example, when the particle size distribution of the metal powder to be used is not appropriate, or when the mixed state of the metal powder and the binder is insufficient and the agglomerates of the metal powder remain in the part, the sintering temperature depends on the part. The vacancy distribution state changes depending on various factors, such as in the case of different values. As a result, the desired thermal conductivity may not be obtained.
In addition, as a result of the entire cooling member being composed of such a porous body, the cooling member may be damaged during long-term use.

  Accordingly, an object of the present invention is to provide a cooling member that can be easily manufactured and has excellent durability and heat dissipation effect.

  The characteristic configuration of the cooling member according to the present invention includes a base material, a nickel (Ni) alloy deposited on the base material and containing nitrogen (N), and gold (Au), silver (Ag), copper A metal layer containing at least one of a pure metal or an alloy of (Cu), platinum (Pt), and palladium (Pd), and formed on the metal layer by irradiating with plasma while supplying nitrogen to the surface of the metal layer And a porous layer.

The porous layer according to this configuration is not obtained by a conventional sintering method or the like, but is obtained by irradiating plasma while supplying nitrogen to a metal layer coated on a substrate. Thereby, nitrogen atoms are once implanted into the metal layer, and the nitrogen atoms diffuse again from the surface of the metal layer into the atmosphere inside the metal layer at a high temperature. At that time, a large number of pores are formed in the metal layer to form a porous layer.
Thus, with the cooling member having this configuration, it is possible to obtain a cooling member having an excellent heat dissipation effect by the porous layer having a large surface area attached to the base material while simplifying the manufacturing process. .

  In the cooling member according to the present invention, the base material forming the porous layer is formed on the base part so as to be able to be exposed to a cooling object that is a fluid and a base part that can contact a cooling target that requires cooling. A plurality of provided protrusions may be provided.

  By providing the cooling member with a base portion that can contact the object to be cooled as in this configuration, heat absorption from the object to be cooled can be promoted. Furthermore, the total area of the base material which forms a porous layer is expanded by providing a some projection part. Therefore, the total area of the pores contributing to cooling becomes sufficiently large, and an excellent cooling effect is exhibited.

  In the cooling member according to the present invention, in the region from the base end portion to the tip end portion of the protrusion, the cross-sectional area of the region on the tip end side is larger than the cross-sectional area of the region on the base end portion side adjacent to the region. It can be configured such that the adjacent cross-sectional areas are not equal in all regions from the base end portion to the tip end portion, which are small or equal.

  The limitation that the distance between the wall surfaces of the protrusions increases as the distance from the base end side to the tip end side means that the shape of the protrusions is tapered toward the tip end side. In the cooling member of this configuration, it means that such a tapered portion is at least one in any region from the base end portion to the tip end portion of the protrusion. That is, the interval between the adjacent protrusions is wider than the interval between the proximal end portions than the interval between the proximal end portion portions. Therefore, when plasma irradiation is performed, the effect of the plasma irradiation can be ensured up to the region of the base end portion of the protrusion, and a uniform porous layer can be formed over the entire region of the protrusion. As a result, a cooling member having an excellent cooling effect can be obtained.

In the cooling member according to the present invention, the substrate is made of aluminum (Al), copper (Cu), iron (Fe), or an alloy thereof, ceramics (Al ₂ O ₃ , AlN, Si ₃ N ₄ ), or these. And the metal layer may be composed of a nickel (Ni) -based coating.

  As in this configuration, the heat absorption speed from the object to be cooled is increased by configuring the base material with a metal such as aluminum or copper having high thermal conductivity, an alloy thereof, ceramics, or a metal composite thereof. Can do. Further, when a nickel-based coating is used, nitrogen atoms implanted into the coating by plasma irradiation are less likely to remain in the nickel-based coating and easily diffuse into the atmosphere again. Therefore, voids are formed in a wide area in the coating, and a cooling member that exhibits a very excellent cooling effect in combination with good thermal conductivity such as aluminum and copper can be obtained.

  In the cooling member according to the present invention, it is preferable that the average pore diameter of the pores opened in the outermost surface of the porous layer is set to a size of 1/100 to 1/5 of the thickness of the metal layer. is there.

  As in this configuration, if the average pore size is 1 / 100th to 1 / 5th the thickness of the metal layer, air or water, which is a cooling fluid, can easily flow through the pores, The cooling member can exhibit good cooling performance.

The perspective view which shows the external appearance of the member for cooling which concerns on this invention. The fragmentary sectional side view of the member for cooling which concerns on this invention. The fragmentary sectional side view of the member for cooling concerning another embodiment. The microscope picture which shows the cross section of the surface vicinity of the member for cooling which concerns on this invention.

〔Overview〕
The cooling member 1 according to the present invention efficiently dissipates heat by placing it in contact with a functional member such as a power source or a computer provided in various devices, or an object to be cooled such as a motor or an engine. More specifically, a power device, a circuit, or the like that constitutes an inverter used as a power source can be suitably used for an apparatus that usually generates a large amount of heat.
Hereinafter, embodiments of the cooling member 1 according to the present invention will be described with reference to the drawings.

[Device shape]
FIG. 1 shows an appearance of a cooling member 1 according to this embodiment, and FIG. 2 shows a partial side sectional view. As shown in FIG. 1, the cooling member 1 has a base portion 3 that can contact an object 2 to be cooled. In the present embodiment, the base portion 3 has a rectangular plate shape. The shape of the base part 3 can be arbitrarily changed according to the shape of the attachment site of the object 2 to be cooled. For example, mounting holes 5 through which bolts 4 are inserted are provided at the four corners of the base portion 3 and are fixed in a state of being in surface contact with the object to be cooled 2 such as the power transistor 2a.

The base part 3 is a part that receives heat from the object to be cooled 2. Therefore, it is preferable to use an aluminum (Al) material, a copper (Cu) material, an alloy thereof, or the like having good thermal conductivity as a member that forms the base portion 3. However, the present invention is not limited to this, and a general steel material or an alloy thereof mainly composed of iron (Fe), ceramics (Al ₂ O ₃ , AlN, Si ₃ N ₄ ), or a metal composite thereof may be used. You can also.

  As shown in FIG. 2, a plurality of protrusions 6 are formed on the base portion 3. It is desirable that the base portion 3 and the protrusion portion 6 are integrally formed of members of the same material from the viewpoint of maintaining good heat conduction. The integral formation can be performed by various methods such as casting, cutting, forging, and welding. The plurality of protrusions 6 can be formed by molding or cutting. The shape of these protrusions 6 can be arbitrarily set according to the total surface area of the cooling member 1 and the type of refrigerant such as air or water. However, it is desirable to provide a gap that can reliably perform the plasma irradiation treatment up to the base end portion of the protrusion 6 depending on the plasma irradiation conditions described later.

  FIG. 2 shows an example in which a large number of rectangular parallelepiped protrusions 6 are provided. The height dimension of the protrusion 6 or the cross-sectional shape perpendicular to the height direction can be arbitrarily set. The cross-sectional shape is not limited to a rectangle and may be a circle or the like.

(Porous layer)
As shown in FIGS. 2 and 3, a porous layer 8 is formed on the surface of the protrusion 6 and the surface of the base 3. In this embodiment, an aluminum material for forming the protrusions 6 and the base 3 is used as a base material, a nickel-based film is plated on the surface of the base material, and plasma irradiation is performed while supplying nitrogen gas to the film. This nickel-based film is an example of a metal layer. Plasma irradiation is performed inside a chamber (not shown), and the conditions are, for example, chamber internal pressure: 300 Pa, plasma current: 4 A, nitrogen gas flow rate: 40 ml / min, substrate heating temperature: 400 ° C., treatment time: 1 hr. . As a result, solid solution of nitrogen atoms into the nickel-based coating and diffusion into the outside air by regasification of nitrogen atoms proceed simultaneously. Holes are formed in the process of gas diffusion.

  The size of the holes varies depending on the nitrogen gas flow rate to be supplied, the processing temperature, the processing time, and the like. In particular, the processing time is easily affected, and the longer the processing time, the larger the hole diameter tends to be.

Phosphorus (P) and boron (B) can be mixed in the nickel-based coating as other elements. By mixing these, the porosity increases. Particularly, the structure becomes hard due to the mixing of phosphorus (P), and the strength of the porous film is improved.
In addition to this, as a film for forming the porous layer 8, at least one of pure metals or alloys such as gold (Au), silver (Ag), copper (Cu), platinum (Pt), palladium (Pd), etc. A metal plating layer including one can also be used.

  For example, a zinc (Zn) film as an intermediate layer may be formed between the base material and the nickel-based film. When the base material is aluminum and the zinc coating is formed, the adhesion of the nickel coating is improved as compared with the case where the nickel coating is directly formed on the aluminum.

  The average pore diameter of the pores opened on the surface of the porous layer 8 is preferably 1/100 to 1/5 of the thickness of the coating. If the hole diameter is too small, the refrigerant cannot smoothly flow through the hole and the cooling effect is impaired. If the pore diameter is excessive, the strength of the porous layer 8 is insufficient and a brittle film is formed.

  The thickness of the nickel-based coating is preferably as thick as possible in the sense that the porous layer 8 is formed thick, but is actually about 1 μm to 100 μm. When this thickness is thin, a sufficient porous region cannot be secured and the cooling effect becomes insufficient. If the thickness is too large, the strength of the coating will be reduced and it will be easy to peel off from the substrate.

  The thickness of the porous layer 8 is better to increase the contact area with the refrigerant. At present, it can be formed up to about 20 μm. When this thickness is thin, a sufficient contact area with the refrigerant cannot be secured, and the cooling effect becomes insufficient. When the thickness is excessively large, the strength of the coating film is lowered, which causes inconveniences such as easy peeling from the substrate.

(Another embodiment)
FIG. 4 shows another embodiment of the cooling member 1.
Here, the shape of the protrusion 6 is configured to be tapered in any region from the base end to the tip. As a result, at the time of plasma irradiation, nitrogen atoms can surely enter the substrate also at the base end portion, and the porous layer 8 can be easily formed evenly to the base end portion side. Moreover, since the space | interval of the projection parts 6 becomes wide near the front-end | tip part, a refrigerant | coolant becomes easy to approach between the projection parts 6. FIG. In particular, since the retention of the refrigerant on the base end side is reduced, the cooling effect can be enhanced.

  FIG. 4 shows an example in which the slope of the protrusion 6 is uniformly formed from the base end portion to the tip end portion, but it is not always necessary to incline the entire length from the base end portion to the tip end portion. For example, only the distal end side or only the proximal end side may be tapered, and the other portions may be configured in a simple prism shape. Furthermore, the half on the base end side along the height direction may be formed of a thick prism, and the half on the tip end side may be a thin prism. In this case, a clear step is formed at the boundary position between the upper and lower prisms. Even in the case of such another type of protrusion 6, it is possible to obtain an effect that the porous layer 8 is easily formed up to the base end of the protrusion 6.

  The cooling member according to the present invention can be used as a power member such as an inverter provided in various devices and a functional member such as a computer, and can be suitably used for cooling a motor or an engine.

3 Base part 6 Protrusion part 8 Porous layer 11 Cooling member

Claims (5)

A substrate;
Nickel (Ni) alloy containing nitrogen (N) deposited on the base material, and pure of gold (Au), silver (Ag), copper (Cu), platinum (Pt), palladium (Pd) A cooling member comprising: a metal layer containing at least one of a metal or an alloy; and a porous layer formed on the metal layer by irradiating plasma while supplying nitrogen to the surface of the metal layer.   The base material forming the porous layer includes a base part that can contact a cooling target that needs to be cooled, and a plurality of protrusions that are provided on the base part so as to be exposed to a fluid refrigerant. The cooling member according to claim 1.   In the region from the base end portion to the tip end portion of the protrusion, the cross-sectional area of the region on the tip end side is smaller than or equal to the cross-sectional area of the region on the base end side adjacent to the region, and The cooling member according to claim 2, wherein the adjacent cross-sectional areas are not equal in all regions reaching the tip. The base material is aluminum (Al) or copper (Cu), iron (Fe) or an alloy thereof, ceramics (Al ₂ O ₃ , AlN, Si ₃ N ₄ ) or a metal composite thereof, and the metal layer The cooling member according to any one of claims 1 to 3, wherein is a nickel (Ni) -based coating.   5. The porous layer according to claim 1, wherein an average pore diameter of pores opened on the outermost surface is 1/100 to 1/5 the thickness of the metal layer. 6. Cooling member.