阅读说明：本技术 热交换器用构件、热交换器、冷却系统 (Member for heat exchanger, and cooling system ) 是由 田岛秀春 高川资起 铃木智子 于 2021-03-02 设计创作，主要内容包括：通过导热性尤其且与冷媒的润湿性优异的被膜对在冷却部或散热部中使用的热交换器的与冷媒接触的金属的表面赋予金属自身没有的特性,实现高效率的热交换器用构件、热交换器、冷却系统。在热交换器运转时,热交换器用构件由金属构成,具有与冷媒接触的面,在所述面上具有金属氧化膜,所述金属氧化膜含有结晶碳并设置有突起,所述突起部的顶点的平均间隔为20nm以上且80nm以下,相邻的突起部的顶点的高度的平均值为10nm以上且70nm以下,且作为所述平均高度除以平均间隔的值的纵横比小于1。(A heat exchanger member, a heat exchanger, and a cooling system having high efficiency are realized by imparting a characteristic that a metal itself does not have to a surface of a metal in contact with a refrigerant of a heat exchanger used in a cooling unit or a heat radiating unit with a film having particularly excellent heat conductivity and wettability with the refrigerant. The member for a heat exchanger is made of metal, has a surface in contact with a refrigerant, and has a metal oxide film on the surface, wherein the metal oxide film contains crystalline carbon and is provided with protrusions, the average interval between the vertexes of the protrusions is 20nm to 80nm, the average value of the heights of the vertexes of adjacent protrusions is 10nm to 70nm, and the aspect ratio, which is the value obtained by dividing the average height by the average interval, is less than 1.)

1. A member for a heat exchanger, which is made of metal, uses a refrigerant, and has a surface that comes into contact with the refrigerant when a heat exchanger manufactured by the member for a heat exchanger is operated, the member for a heat exchanger being characterized in that,

a metal oxide film containing crystalline carbon and provided with a protrusion portion on the surface,

the average distance between the apexes of the protrusions is 20nm to 80nm,

the height of the peaks of adjacent protrusions has an average value of 10nm to 70nm,

and an aspect ratio, which is a value of the average height divided by the average interval, is less than 1.

2. A member for a heat exchanger according to claim 1,

the content ratio of crystalline carbon contained in a range of 3 to 5nm from the surface of the metal oxide film is 20 at% or more and 40 at% or less.

3. A member for a heat exchanger according to claim 1 or 2,

the thickness of the metal oxide film is 100nm to 300 nm.

4. A heat exchanger, characterized in that,

a member for a heat exchanger according to any one of claims 1 to 3 is provided.

5. A cooling system, characterized in that,

there is provided the heat exchanger of claim 4.

Technical Field

The present invention relates to a member for a heat exchanger that uses a refrigerant having a cooling effect better than that of water by imparting characteristics other than the inherent characteristics of a metal to the surface of the metal, and an apparatus having the member.

Background

In operation of a cooling system using a refrigerant, the refrigerant circulates through the system, and in the cooling unit, the object is cooled by vaporization of the refrigerant flowing through the heat exchanger, and in the heat exchanger of the heat radiating unit, the refrigerant is cooled and liquefied by outside air or the like. In the cooling system, the size of the system in which the restriction is placed and the energy consumption of the pump for circulating the refrigerant are determined by the efficiency of radiating heat to the outside and liquefying the refrigerant in the heat exchanger of the heat radiating portion (hereinafter referred to as "liquefying efficiency"), the efficiency of vaporizing the refrigerant in the heat exchanger of the cooling portion and taking away the heat (hereinafter referred to as "vaporizing efficiency"), and the pressure loss of the refrigerant flowing in the pipe.

On the other hand, in recent years, the amount of information and the speed of semiconductor device processing have been further increased, and high integration as a countermeasure therefor has resulted in an increase in the installation limit of a corresponding cooling system and power consumption.

Therefore, in order to provide a degree of freedom in cooling system arrangement and reduce energy consumption, technologies regarding liquefaction efficiency, gasification efficiency, and reduction of pressure loss are being studied. Such a technique is disclosed in patent document 1, for example.

Patent document 1 describes the following method: by adding a gas-liquid separation unit to the cooling system, the gasification efficiency of the cooling unit and the liquefaction efficiency of the heat dissipation unit are improved.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2004-190928

Disclosure of Invention

Problems to be solved by the invention

However, in the technique of patent document 1, it is necessary to additionally provide a gas-liquid separation unit in the cooling system, and there is a problem that installation of the cooling system is limited and the cost is significantly increased.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a heat exchanger member, a heat exchanger, and a cooling system having high efficiency by providing a surface of a metal in contact with a refrigerant of a heat exchanger used in a cooling unit or a heat radiating unit with a film having excellent thermal conductivity and excellent wettability with the refrigerant.

Means for solving the problems

In order to solve the above problem, a heat exchanger member according to the present invention is a heat exchanger member made of metal, and has a surface that comes into contact with a refrigerant when a heat exchanger manufactured by using the heat exchanger member is operated, the surface having a metal oxide film that contains crystalline carbon and is provided with protrusions, the average distance between the apexes of the protrusions is 20nm or more and 80nm or less, the average value of the heights of the apexes of adjacent protrusions is 10nm or more and 70nm or less, and the aspect ratio, which is the value obtained by dividing the average height by the average distance, is less than 1.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the heat exchanger member can be provided with a function of improving the liquefaction and vaporization efficiency of the heat exchanger.

Drawings

Fig. 1 is a schematic view showing a semiconductor cooling system using a member for a heat exchanger according to a first embodiment of the present invention.

Fig. 2 is a view showing a member for a heat exchanger according to a first embodiment of the present invention.

Fig. 3 is a schematic view showing a cross section viewed along an arrow a-a of fig. 2.

Fig. 4 is an AFM observation result of the refrigerant contact surface of the heat exchanger member according to the first embodiment of the present invention.

Fig. 5 is a diagram showing an apparatus for making the first embodiment of the present invention.

Fig. 6 is a graph showing a time chart of the supported electrolytic density for producing the first embodiment of the present invention.

Fig. 7 is a diagram showing a liquefaction test in the first embodiment of the present invention.

Fig. 8 is an SEM perspective view of the first embodiment of the present invention.

Fig. 9 is an SEM perspective view of a comparative example according to the first embodiment of the present invention.

Fig. 10 is a view showing a member for a heat exchanger according to a second embodiment of the present invention.

Fig. 11 is a schematic view showing a cross section viewed along an arrow a-a of fig. 10.

Fig. 12 shows AFM observation results of the refrigerant contact surface of the heat exchanger member according to the second embodiment of the present invention.

Fig. 13 is a diagram showing an apparatus for making the second embodiment of the present invention.

Fig. 14 is a graph showing a time chart of the supported electrolytic density for producing the second embodiment of the present invention.

Fig. 15 is a view showing a cooling test of the second embodiment of the present invention.

Fig. 16 is an SEM perspective view of the second embodiment of the present invention.

Fig. 17 is an SEM perspective view of a comparative example according to the second embodiment of the present invention.

Detailed Description

(first embodiment)

Hereinafter, an embodiment of the present invention will be described with reference to fig. 1 to 9.

< Structure of semiconductor Cooling System with Member mounted >

Fig. 1 is a schematic diagram illustrating a semiconductor cooling system 100. The semiconductor cooling system 100 includes a cooling unit (heat exchanger) 110, a heat radiating unit (heat exchanger) 120, a compressor 130, an expansion valve 140, and the like.

The heat radiation unit 120 includes a heat exchanger 121 and a fan 122, and heat radiated when the refrigerant is liquefied inside the heat exchanger 121 is radiated to the outside of the system by the fan 122. The heat exchanger member of the present invention refers to a member constituting the heat exchanger 121. In the following description, the heat exchanger member will be described as a pipe for liquefying a refrigerant therein, that is, a member constituting the heat exchanger 121.

< Structure of Member >

Fig. 2 and fig. 3, which is a sectional view taken along a line a-a in fig. 2, show a tube constituting the heat exchanger 121, which is a specific example of the heat exchanger member of the present invention. As shown in fig. 3, a metal base material 121A made of a main material (aluminum, stainless steel, copper, or the like) forming a tube has a crystalline carbon-containing oxide film 121C, and fine protrusions 121B are provided on the crystalline carbon-containing oxide film 121C. The crystalline carbon-containing oxide film 121C having the minute protrusions 121B is a metal oxide film containing crystalline carbon, and is provided with the following functions: in the heat exchanger 121, the wettability of the refrigerant with the inner surface of the tube in contact with the refrigerant constituting the gas is improved, and the efficiency of cooling the refrigerant is improved by the high thermal conductivity of the crystalline carbon contained therein.

The pipe is made of metal pipes such as an aluminum pipe, a stainless steel pipe or a copper pipe. The wall thickness and length of the tube are not particularly limited and are appropriately determined depending on the purpose of use.

The crystalline carbon-containing oxide film 121C is an oxide of the same or similar metal as the metal base material and contains crystalline carbon. The thickness of the crystalline carbon-containing oxide film 121C may be 10nm to 300 nm. In addition, in order to make full use of the thermal conductivity of the contained crystalline carbon-containing oxide film 121C and to improve the liquefaction efficiency, the thickness of the crystalline carbon-containing oxide film is preferably 100nm to 300 nm. The carbon content of the carbon-containing oxide film 121C may be 5 to 50 at% at a distance of 3 to 5nm from the surface (opposite surface to the surface in contact with the metal base material 121A). In order to have the characteristics imparted by the inclusion of crystalline carbon and maintain the strength of the coating, the content ratio of crystalline carbon contained in the carbon-containing oxide film 121C is preferably 8 at% to 40 at% at a distance of 3nm to 5nm from the surface.

In order to improve the thermal conductivity, the crystalline carbon contained in the crystalline carbon-containing oxide film 121C is preferably a carbon nanotube, fullerene, graphene, or the like.

The fine protrusions 121B are provided on the surface of the crystalline carbon-containing oxide film 121C (the surface opposite to the surface in contact with the metal base material 121A), the average distance between adjacent apexes of the fine protrusions 121B is 20nm or more and 80nm or less, the average value of the heights of the apexes of the protrusions is 10nm or more and 70nm or less, and the aspect ratio, which is the value obtained by dividing the average distance by the average height, may be less than 1.

In order to provide the fine protrusions 121B with higher wettability to the refrigerant, it is more preferable that the average distance between adjacent apexes of the fine protrusions 121B is 25nm to 65nm, the average height of the apexes of the protrusions is 15nm to 55nm, and the aspect ratio, which is the value of the average height divided by the average distance, is less than 0.83.

Hereinafter, an example of the first embodiment will be described with reference to fig. 5 to 8. The heat exchanger 121 in the embodiment is made of an aluminum pipe having an outer diameter of 8mm (inner diameter of 6mm) × 220 mm. In order to provide the crystalline carbon-containing oxide film 121C having the minute protrusions 121B on the inner surface of the aluminum pipe (metal base material 121A), the following process is performed.

First, the aluminum tube (metal substrate 121A) was subjected to immersion degreasing in ethanol (immersion time: 30 minutes). Then, as shown in fig. 5, the aluminum tube connected to the circuit 400 and the electrode 404 were immersed in the bath 300 containing the treatment liquid 301 in a state where the electrode 404 was inserted so as not to contact the inner surface of the aluminum tube, and the electrode 404 was connected to the circuit 400 while being positioned inside the aluminum tube and made of SUS304(304 stainless steel). With respect to the treatment liquid 301 in the bath 300, sodium hydroxide and a 0.2% single-walled carbon nanotube dispersion dispersed in purified water (purified water) by a dispersant were added to the purified water so that the concentrations thereof reached 0.85g/l and 1.35ml/l, respectively, and the temperature was adjusted so that the liquid temperature reached 30 ℃.

When the current flows in the direction of the arrow shown in fig. 6 as the current in the + direction, the aluminum pipe is applied with a voltage in the mode shown in fig. 6 through the rectifier 401, the rectifier 402, and the changeover switch 403.

Finally, the mixture was washed with water and dried in a thermostatic bath (80 ℃ C., 30 minutes). In this way, the heat exchanger 121 is configured by providing the crystalline carbon-containing oxide film 121C of 200nm on the surface of the aluminum pipe (metal base material 121A) and providing the minute projections 121B (fig. 4) on the surface of the crystalline carbon-containing oxide film 121C, with the average interval of the apexes of the adjacent minute projections 121B being 61nm and the average height of the minute projections 121B being 50 nm.

< verification test >

Here, the characteristics required for the heat exchanger in the heat radiation portion will be described. The heat exchanger in the heat radiating portion liquefies the refrigerant by extracting heat from the refrigerant in a high-temperature and high-pressure gas state vaporized in the cooling portion by the compressor and radiating the heat to the outside. In this case, it is necessary to liquefy all the refrigerant so that the refrigerant can circulate in the system. Therefore, if the liquefaction efficiency per unit area of the refrigerant contact of the heat exchanger is deteriorated, the size of the heat exchanger is increased, the installation of the cooling system is restricted, and the cost is significantly increased.

In general, in a semiconductor cooling system, a heat radiating portion is larger than a cooling portion, and thus the liquefaction efficiency affects the size and cost of the entire unit. Therefore, the heat exchanger of the heat radiation unit needs to have improved liquefaction efficiency.

The tube constituting the heat exchange of the present invention can have a very small contact angle indicating wettability with a refrigerant (a so-called freon such as fluorocarbon, a mixture of methyl nonafluorobutyl ether and methyl nonafluoroisobutyl ether, or the like). For example, in the case of aluminum, the contact angle can be changed from untreated 4.18 ° to 0.67 ° by configuring the structure of the present invention, and thus the refrigerant can be easily flowed and recovered. In addition, in the structure of the present invention, crystalline carbon having excellent thermal conductivity such as carbon nanotubes is contained, and therefore, the heat exchange property is excellent. Therefore, the heat exchanger of the present invention is excellent in liquefaction efficiency.

As shown in fig. 7, outside the thermostatic bath 510, the heat exchanger 121 of the present invention shown in fig. 2 to 4 and 8 (the content of crystalline carbon having a contact angle of 0.67 ° with respect to the refrigerant is 10% (5 nm from the surface)) and the heat exchanger 522 (the content of crystalline carbon having a contact angle of 4.18 ° with respect to the refrigerant is 0% (5 nm from the surface)) having an inner surface of the same shape as that of the present invention as shown in fig. 9 and having an untreated aluminum pipe for comparison were connected to silicone tubes 541 and 542, the silicone tubes 541 and 542 were connected to refrigerant containers 531 and 532, and the refrigerant containers 531 and 532 were provided in the thermostatic bath 510 of the liquefaction characteristic evaluator 500 shown in fig. 7 and sealed with the refrigerant.

Then, the refrigerant in the refrigerant containers 531, 532 is evaporated by operating the thermostatic bath 510 to 70 ℃, the refrigerant vaporized in the respective heat exchangers 121, 522 is introduced, the refrigerant cooled and liquefied at room temperature (15 ℃) is recovered by the recovery containers 551, 552, the liquefied weight is measured, and the weight of the refrigerant introduced into the refrigerant containers 531, 532 is divided by the weight of the refrigerant, respectively, to derive the liquefaction efficiency.

As a result, it was confirmed that the liquefaction efficiency of the heat exchanger 121 of the present invention was 71.1% and higher than the liquefaction efficiency 59.8 of the untreated heat exchanger 522 for comparison.

In the present embodiment, the wet electrolytic treatment under the above-described conditions is used to form the crystalline carbon-containing oxide film 121C having the fine protrusions 121B on the surface thereof, but the present invention is not limited thereto, and the crystalline carbon-containing oxide film may be formed under other conditions or by other treatment methods (sputtering using a metal oxide target containing carbon nanotubes, a sol-gel method, or the like). However, the wet electrolytic treatment is superior to other treatment methods in terms of cost.

As described above, the heat exchanger 121 (or the heat exchanger member) according to the present invention can achieve the following effects as compared with a conventional mechanism in which a mechanism such as a gas-liquid separator is added: since the size of the entire cooling system can be reduced, the installation restriction can be relaxed, and a large change is not required, a portion related to the cooling system does not need to be changed, and an increase in cost can be suppressed.

The first embodiment of the present invention is not limited to the tube-shaped member constituting the heat exchanger 121, and may be a member constituting a partition wall or an inner fin provided inside the heat exchanger to cool the refrigerant, and in any case, the same effects as those of the member constituting the heat exchanger 121 can be achieved.

It is to be noted that the same effects as those of the heat exchanger 121 can be achieved by a heat exchanger including members constituting the heat exchanger 121, members constituting partition walls provided inside the heat exchanger for cooling the refrigerant, and inner fins.

Further, the cooling system provided with the heat exchanger constituted by the members of the embodiment of the present invention can obviously achieve the same effects as those of the heat exchanger 121 described above, and therefore can achieve the following effects: since the size of the entire cooling system can be reduced, the installation restriction can be relaxed, and a large change is not required, a portion related to the cooling system does not need to be changed, and an increase in cost can be suppressed.

(second embodiment)

Hereinafter, an embodiment of the present invention will be described with reference to fig. 10 to 17.

< Structure of semiconductor Cooling System with Member mounted >

Fig. 1 is a schematic diagram illustrating a semiconductor cooling system 100. The semiconductor cooling system 100 includes a cooling unit 110, a heat radiating unit 120, a compressor 130, an expansion valve 140, and the like.

The cooling unit 110 includes a heat exchanger 111 and a semiconductor 150, and when a refrigerant is vaporized in the heat exchanger 111, heat generated in the semiconductor 150 is removed, and the semiconductor 150 is cooled. The heat exchanger member of the present invention is a member constituting the heat exchanger 111. In the following description, the heat exchanger member will be described as a member constituting the heat exchanger 111, which is a tube for vaporizing the refrigerant therein.

< Structure of Member >

Fig. 10 and fig. 11, which is a sectional view taken along a line a-a in fig. 10, show a tube constituting the heat exchanger 111, which is a specific example of the heat exchanger member of the present invention. As shown in fig. 11, a metal base 111A made of a main material (copper, aluminum, stainless steel, or the like) forming a tube has a crystalline carbon-containing oxide film 111C, and fine protrusions 111B are provided on the crystalline carbon-containing oxide film 111C. The crystalline carbon-containing oxide film 111C having the fine protrusions 111B is a metal oxide film containing crystalline carbon, and the heat exchanger 111 is provided with the following functions: the wettability of the inner surface of the tube, which is in contact with the liquid refrigerant, with the refrigerant is improved, and even if the refrigerant starts to vaporize during cooling, the contact area with the refrigerant is increased, and the heat conductivity is improved by the crystalline carbon having a high heat conductivity contained therein, so that the heat transfer efficiency (vaporization efficiency) from the semiconductor 150 to the refrigerant via the heat exchanger 111 is improved.

The tube is made of metal tubes such as copper tubes, aluminum tubes or stainless steel tubes. The wall thickness and length of the tube are not particularly limited and are appropriately determined depending on the purpose of use.

The crystalline carbon-containing oxide film 111C is an oxide of the same or similar metal as the metal base material and contains crystalline carbon. The thickness of the carbon-containing crystalline oxide film 111C may be 10nm to 300 nm. In order to make full use of the thermal conductivity of the crystalline carbon-containing oxide film 111C and to improve the vaporization efficiency (i.e., the efficiency of transferring heat from the semiconductor to the refrigerant), the thickness of the crystalline carbon-containing oxide film is preferably 100nm to 300 nm. The carbon content of the carbon-containing oxide film 121C may be 5 to 50 at% at a distance of 3 to 5nm from the surface (opposite surface to the surface in contact with the metal base material 121A). In order to have the characteristics imparted by the inclusion of crystalline carbon and maintain the strength of the coating, the content ratio of crystalline carbon contained in the carbon-containing oxide film 121C is preferably 8 at% to 40 at% at a distance of 3nm to 5nm from the surface.

In order to improve the thermal conductivity, the crystalline carbon contained in the crystalline carbon-containing oxide film 111C is preferably a carbon nanotube, fullerene, graphene, or the like.

The fine protrusions 111B are provided on the surface of the crystalline carbon-containing oxide film 111C (the surface opposite to the surface in contact with the metal substrate 111A), the average distance between adjacent apexes of the fine protrusions 111B is 20nm to 80nm, the average height of the apexes of the protrusions is 10nm to 70nm, and the aspect ratio, which is the value obtained by dividing the average height by the average distance, is less than 1.

In order to provide the fine protrusions 111B with higher wettability to the refrigerant, it is more preferable that the average distance between adjacent apexes of the fine protrusions 111B is 25nm to 65nm, the average height of the apexes of the protrusions is 15nm to 55nm, and the aspect ratio, which is the value of the average height divided by the average distance, is less than 0.83.

Hereinafter, a second embodiment will be described with reference to fig. 13 to 16Examples are given. The heat exchanger 111 in the embodiment is provided with a hole at the center as shown in FIG. 15The length of the through hole is 50mm, and the through hole is made of an 11mm square copper rod. For the square copper bar (metal substrate 111A)The surface of the hole is provided with a crystalline carbon-containing oxide film 111C having minute protrusions 111B, and the following process is performed.

First, the square copper rod (metal base 111A) was immersed in ethanol to degrease (immersion time: 30 minutes). Next, as shown in fig. 13, the square copper bar connected to the circuit 600 and the electrode 604 were immersed in the bath 700 containing the treatment liquid 701 in a state where the electrode 604 was inserted so as not to contact the inner surface of the hole opened in the square copper bar, and the electrode 604 was connected to the circuit 600 inside the square copper bar and manufactured from SUS304(304 stainless steel). Sodium hydroxide and a 0.2% single-walled carbon nanotube dispersion dispersed in purified water with a dispersant were added to the treatment liquid 701 in the bath 700 so that the concentrations thereof reached 0.85g/l and 1.35ml/l, respectively, and the temperature was adjusted so that the liquid temperature reached 30 ℃.

When the current flowing in the direction of the arrow shown in fig. 14 is regarded as a current in the + direction, a voltage is applied to the aluminum pipe through the rectifier 601, the rectifier 602, and the changeover switch 603 in the mode shown in fig. 14.

Finally, the mixture was washed with water and dried in a thermostatic bath (80 ℃ C., 30 minutes). In this way, the heat exchanger 111 was constructed by providing the crystalline carbon-containing oxide film 111C of 150nm on the surface of the square copper rod (metal base material 111A) and providing the fine protrusions 111B (fig. 12) on the surface of the crystalline carbon-containing oxide film 111C, with the average distance between the apexes of the adjacent fine protrusions 111B being 30.0nm and the average height of the fine protrusions 111B being 16.4 nm.

< verification test >

Here, the characteristics required for the heat exchanger in the cooling portion will be described. In the heat exchanger in the cooling unit, the refrigerant that is liquefied at the heat radiating portion and passes through the expansion valve to become a low-temperature low-pressure liquid state is cooled by being vaporized by receiving heat generated by the semiconductor to be cooled. In this case, if the heat generated in the semiconductor cannot be efficiently extracted, the temperature of the semiconductor rises and is eventually destroyed. On the other hand, in recent years, semiconductor integration has been increasing, and thus, heat generated during operation has also been increasing. Therefore, it is necessary to liquefy the entire refrigerant so that the refrigerant can circulate in the system with improved efficiency of vaporizing the refrigerant and removing heat (hereinafter referred to as vaporization efficiency). Therefore, if the liquefaction efficiency per unit area of the refrigerant contact of the heat exchanger is deteriorated, the size of the heat exchanger is increased, and the installation of the cooling system is restricted, which significantly increases the cost.

In general, in a semiconductor cooling system, a heat radiating portion is larger than a cooling portion, and therefore the vaporization efficiency affects the size and cost of the entire unit.

Therefore, the heat exchanger of the cooling portion needs to improve the efficiency of vaporizing the refrigerant and taking away heat (vaporization efficiency), that is, the heat transfer coefficient to the refrigerant.

Further, as higher integration progresses, the refrigerant is gasified in front of the semiconductor due to heat generated in the semiconductor, and burnout (burnout) occurs in which the refrigerant cannot be cooled regardless of the amount of the refrigerant flowing therethrough, which becomes a factor limiting the integration of the semiconductor. Therefore, it is desirable to increase the heat transfer coefficient along with the critical heat flux at which burnout occurs.

The inner surfaces of the holes in the square rods constituting the heat exchanger 111 of the present invention can have a very small contact angle indicating wettability with a refrigerant (a so-called freon such as fluorocarbon, a mixture of methyl nonafluorobutyl ether and methyl nonafluoroisobutyl ether, or the like). For example, in the case of copper, the contact angle can be changed from untreated 5.72 ° to 1.77 ° by configuring the structure of the present invention, and therefore, even if the refrigerant starts to vaporize, the refrigerant can contact the inner surface of the hole over a larger area, and heat is efficiently transferred. In addition, in the structure of the present invention, crystalline carbon having excellent thermal conductivity such as carbon nanotubes is contained, and therefore, the heat exchange property is further improved. Therefore, the heat exchanger of the present invention is excellent in vaporization efficiency (heat transfer coefficient).

The heat exchanger 111 of the present invention shown in fig. 10 to 12 and 16 (contact angle with refrigerant: 1.77 ° and content of crystalline carbon: 12% (at 5nm from the surface)) and the heat exchanger 911 (contact angle with refrigerant: 5.72 ° and content of crystalline carbon: 0% (at 5nm from the surface)) composed of an untreated square copper rod having an inner surface like that shown in fig. 17 and the same shape as that of the present invention for comparison were alternately provided in the measurement unit of the vaporization characteristic evaluation device 800 shown in fig. 15, and the ceramic heater 151 or 152, which looks like a semiconductor, was placed on the upper surface of the provided heat exchangers 111, 911.

Then, the pump of the vaporization characteristic evaluation device 800 was operated to circulate the refrigerant in the vaporization characteristic evaluation device, and then the output of the ceramic heater was increased to measure the temperature of each part, thereby deriving the heat transfer coefficient and the critical heat flux of the heat exchanger 111 of the present invention and the untreated heat exchanger 911 for comparison with respect to the refrigerant.

As a result, it was confirmed that the heat transfer coefficient of the heat exchanger 111 of the present invention was 6.72W/(m)²K) The critical heat flux is 4.47W/m²The heat transfer coefficient of the untreated heat exchanger 911 used for comparison was 5.82W/(m)²K) And a critical heat flux of 4.32W/m²Compared with the prior art, the method is improved.

In the present embodiment, the wet electrolytic treatment under the above-described conditions is used to form the crystalline carbon-containing oxide film 111C having the fine protrusions 111B on the surface, but the present invention is not limited thereto, and the crystalline carbon-containing oxide film may be formed under other conditions or by other treatment methods (sputtering using a metal oxide target containing carbon nanotubes, a sol-gel method, or the like). However, the wet electrolytic treatment is superior to other treatment methods in terms of cost.

As described above, the heat exchanger 111 (also, a member for a heat exchanger) according to the present invention has an excellent heat transfer coefficient (vaporization efficiency) as compared with the conventional heat exchanger 911 in which the contact surface with the refrigerant is not treated, and therefore, the following effects can be achieved: the size of the whole cooling system can be reduced, the limitation can be relaxed, and the critical heat flux can be improved, so that the integration limit of the semiconductor can be updated.

The second embodiment of the present invention is not limited to the member having the square rod shape with holes such as the heat exchanger 111, and may be a member having partition walls or an inner fin provided inside the heat exchanger to vaporize the refrigerant, and in any case, the same effects as those of the member constituting the heat exchanger 111 can be achieved.

It is to be noted that a heat exchanger including a member constituting the heat exchanger 111, a member constituting a partition wall provided inside the heat exchanger to vaporize the refrigerant, an inner fin, or the like can achieve the same effects as those of the heat exchanger 111.

Further, the cooling system provided with the heat exchanger constituted by the members of the embodiment of the present invention can obviously achieve the same effects as those of the heat exchanger 111 described above, and therefore can achieve the following effects: since the size of the entire cooling system can be reduced, the installation restriction can be relaxed, and a large change is not required, a portion related to the cooling system does not need to be changed, and an increase in cost can be suppressed, and the limit of integration of the semiconductor can be updated.

Further, it was confirmed that the inner surface of the member (tube) as an embodiment of the present invention can reduce the pressure loss at the time of refrigerant circulation in a state where the liquid and the gas in the cooling system are mixed, and for example, by performing the treatment in examples 1 and 2 on the inner surface of the stainless steel tube, the pressure loss can be reduced by 37% when the volume mixing ratio of the gas and the liquid is 30%, as compared with the case of untreated pressure loss.

Therefore, the energy consumption of the pump for circulating the refrigerant can be reduced.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in the respective embodiments are also included in the technical scope of the present invention. Further, by combining the technical means disclosed in the respective embodiments, new technical features can be formed.

Industrial applicability of the invention

The present invention can be used for a heat exchanger member requiring improvement in liquefaction characteristics and/or vaporization characteristics.

Description of the reference numerals

100: a semiconductor cooling system,

121: heat exchangers (heat-radiating parts),

121A: a metal base material,

121B: micro-protrusions,

121C: crystalline carbon-containing oxide film (metal oxide film),

300: a bath groove,

400: an electrical circuit.