JP2013007545A - Heat pipe, manufacturing method of the heat pipe, and plasma etching device for manufacturing the heat pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that conventionally, wettability to an operating fluid, of a metal layer of an inner circumference surface of a wall of an air-tight container of a heat pipe is unsatisfactory, accordingly a heat transfer rate to the operating fluid from the inner circumference surface of the wall of the air-tight container is small, consequently heat transport capacity is insufficient.SOLUTION: A heat pipe includes a cylindrical air-tight container 1 for accommodating an operating fluid capable of evaporating and condensing within an operating temperature range. The air-tight container 1 is formed of a cylinder part 11 and circular lid parts 12a, 12b closing the cylinder part 11. The cylinder part 11 and the circular lid parts 12a, 12b are made of a metal-impregnated carbon fiber-reinforced carbon-material. In this case, a carbon-containing rate of the metal-impregnated carbon fiber-reinforced carbon-material is low in the inside of the wall of the air-tight container 1 and is high in the inner circumference surface side of the wall of the air-tight container 1. On the inner circumference surface of the wall of the air-tight container 1, a nanometer-order concavo-convex structure NS is formed.

Description

  The present invention relates to a heat pipe made of metal-impregnated carbon fiber reinforced carbon with a high internal carbon content, a method for producing the same, and a plasma etching apparatus for producing the same.

  In recent years, electronic devices such as semiconductor devices have been integrated with high density. As a result, power consumption has increased rapidly, and heat generation density has also increased rapidly with the amount of heat generated. For this reason, in the forced air absorption structure using the Peltier element and the forced air cooling structure using the heat sink and the heat radiating fan, the cooling capacity is beginning to be limited, and the liquid cooling structure is being adopted as a higher cooling capacity.

  Heat pipes have attracted attention as a hot-wheel feeding member that exhibits an effect in combination with these cooling means.

  FIG. 11 is a perspective view showing a first conventional heat pipe.

  In FIG. 11, the heat pipe is a cylindrical airtight container 1101 that contains a working fluid (not shown) that can evaporate and condense in the operating temperature range, and a wick (capillary structure) provided inside the airtight container 1101. 1102.

  In FIG. 11, one side of the airtight container 1101 is the heat receiving evaporation region R1, and the other side is the heat radiation condensing region R2. Accordingly, when the heat receiving evaporation region R1 is positioned in the vicinity of the heat generating source, the working fluid in the heat receiving evaporation region R1 evaporates due to the heat of the heat generating source, and flows to the heat radiation condensing region R2 as steam as indicated by the arrow S1. On the other hand, the vapor in the heat radiation condensing region R2 is condensed by heat radiation, and flows to the heat receiving vaporization region R1 by the capillary phenomenon of the wick 1102 as a liquid as indicated by an arrow S2. In this way, the working fluid circulates between the heat receiving evaporation region R1 and the heat radiation condensing region R2, so that the heat pipe acts as a heat transport member, and heat from the heat generating source is received and evaporated by the airtight container 1101 of the heat pipe. It transports from area | region R1 to remote heat radiation condensation area | region R2, and equalizes the temperature of the whole heat pipe. By spatially separating the heat receiving evaporation region R1 and the heat radiation condensing region R2, restrictions on design conditions such as size can be relaxed. At this time, the temperature range of the heat receiving evaporation region R1 and the heat radiation condensation region R2 is the operating temperature range of the working fluid.

  In the heat receiving evaporation region R1 of the airtight container 1101 in FIG. 11, when heat from the outside is transferred to the inside, the thermal resistance in the orthogonal direction of the wall of the airtight container 1101 is reduced, that is, the thermal conductivity is increased. Similarly, in the heat radiation condensation region R2 of the airtight container 1101, when heat is transferred from the inside to the outside, the thermal resistance in the orthogonal direction of the wall of the airtight container 1101 is also reduced, that is, the heat It is necessary to increase the conductivity. That is, in order to improve the heat transport capability (both speed and quantity) of the heat pipe, it is necessary to increase the anisotropic thermal conductivity in the orthogonal direction of the wall of the hermetic container 1101.

  12A and 12B show a second conventional heat pipe, in which FIG. 12A is an external view, and FIG. 12B is a cross-sectional view taken along the line BB of FIG.

In FIG. 12, the heat pipe contains a working fluid and has a cylindrical airtight container 1201 having a wick uneven inner surface 201a, and a metal layer 1202 made of, for example, a nickel coating layer provided on the wick uneven inner surface 1201a of the airtight container 1201. And a reinforcing member 1203 provided on the outer peripheral surface of the wall of the airtight container 1201. In FIG. 12, R1 indicates a heat receiving evaporation region, and R2 indicates a heat radiation condensation region.

In FIG. 12, the wall of the hermetic container 1201 uses carbon fiber reinforced carbon as an anisotropic heat conductive material in the orthogonal direction of the wall having a thermal conductivity exceeding that of the metal, and is further orthogonal to the wall of the hermetic container 1201. In order to increase the anisotropic thermal conductivity in the direction, the gap between the carbon fiber reinforced carbons is impregnated with a metal. That is, the airtight container 1201 is made of metal-impregnated carbon fiber reinforced carbon.

In order to further increase the thermal conductivity between the airtight container 1201 and the working fluid, the metal layer 1202 is provided on the wick uneven inner surface 1201a of the airtight container 1201 to improve the wettability with the working fluid. The better the wettability, the lower the surface tension. Therefore, when the wettability of the working fluid is improved, the heat transport capability is increased and the thermal conductivity in the orthogonal direction of the wall of the airtight container 1201 is substantially increased.

Further, the metal-impregnated carbon fiber reinforced carbon mainly has vertical anisotropy in the orthogonal direction of the wall of the hermetic container 1201, so that the internal pressure of the working fluid sealed inside the hermetic container 1201 is increased. On the other hand, the airtight container 1201 is fragile. In order to prevent this, the reinforcing member R03 provided on the wall outer peripheral surface of the airtight container 1201 is made of carbon fiber reinforced carbon oriented in the parallel direction of the wall of the airtight container 1201.

JP 2003-336977 A

JIS R3257 (1999) “Method of testing the wettability of substrate glass surface”

  In order to further improve the heat transfer capability of the heat pipe of FIG. 12, it is necessary to increase the heat transfer capability of the working fluid by increasing the thermal conductivity from the inner peripheral surface of the airtight container 1201 to the working fluid, in particular. In order to increase the thermal conductivity, it is necessary that the wall inner peripheral surface of the airtight container 1201 has good wettability (friendly) with respect to the working fluid. However, the metal layer 203 on the inner peripheral surface of the airtight container 1201 in the heat pipe of FIG. 12 cannot be said to have good wettability with respect to the working fluid. The thermal conductivity is small, and as a result, the endothermic evaporation rate in the endothermic evaporation region R1 and the heat dissipation condensation rate in the endothermic evaporation region R2 are reduced, and there is a problem that the heat transport capability is insufficient.

There are various wettability evaluation apparatuses, and as an example, there is an apparatus that evaluates by a contact angle of a droplet (see Non-Patent Document 1). That is, referring to FIG. 13, when evaluating the wettability of the solid 1301 to the fluid 1302, the fluid 1302 is dropped on the solid 1301 by a small amount, for example, 2 μL, and an image 1302 ′ of the fluid 1302 by the mirror 1303 is observed with the microscope 1304. In this case, if the surface tension of the solid 1301 is γ _S , the surface tension of the fluid 1302 is γ _F , and the surface tension γ _{SF at the} interface of the solid 3011 fluid 1302, the better the wettability (affinity), the surface tension γ _{S 1} , γ _F , and γ _SF become smaller, and the contact angle θ of the fluid 1302 approaches 0 degrees. On the other hand, the worse the wettability (relaxation), the smaller the surface tensions γ _S , γ _F and γ _SF , and the contact angle θ of the fluid 1302 approaches 180 degrees. The contact angle of the metal layer 1203 in FIG. 12 with respect to the working fluid (for example, typical water) is as large as 30 to 40 degrees, and the wettability cannot be said to be good.

  In order to solve the above-described problems, a heat pipe according to the present invention includes a hermetic container for containing a working fluid that can be evaporated and condensed within an operating temperature range. It consists of impregnated carbon fiber reinforced carbon material, and the carbon content of this metal impregnated carbon fiber reinforced carbon material is higher on the inner wall surface side than the inside of the wall of the airtight container. It is characterized in that a concavo-convex structure having a nanometer order is formed on.

  The heat pipe manufacturing method according to the present invention includes a forming step of forming a film-like carbon fiber reinforced plastic containing carbon fibers in a network shape into a cylindrical shape, and firing many film-like carbon fiber reinforced plastics. A firing process for generating a carbon fiber skeleton having a plurality of pores, a carbon solvent immersing process for immersing the inner peripheral surface of the carbon fiber skeleton in a solvent containing carbon, and an uncoating process for uncoating the carbon fiber skeleton after the carbon solvent immersing process; After the calcination process, the process of impregnating the carbon fiber skeleton with molten metal to produce a metal-impregnated carbon fiber reinforced carbon material with high internal carbon content, and plasma etching of the inner surface of the metal impregnated carbon fiber reinforced carbon material with high internal carbon content And a plasma etching process for forming a concavo-convex structure of nanometer order on the inner surface, and after the plasma etching process, the inner surface has a high carbon content metal-impregnated carbon fiber strength. A working fluid enclosing step of enclosing the internal working fluid of the carbon material, after the working fluid enclosing step, and a step of bonding the lid to the opposite ends of the inner surface high carbon content metal-impregnated carbon fiber reinforced carbon material.

  Furthermore, in the plasma etching apparatus for heat pipes according to the present invention, the airtight container for containing the working fluid that can be evaporated and condensed within the operating temperature range is made of a metal-impregnated carbon fiber reinforced carbon material, and the metal-impregnated carbon fiber In the heat pipe plasma etching apparatus in which the carbon content of the reinforced carbon material is higher on the inner peripheral surface side than the inside of the wall of the airtight container, a support base for supporting the metal-impregnated carbon fiber reinforced carbon material with a high inner carbon content; A rod-shaped inner electrode slidably provided on the inner surface side of the metal-impregnated carbon fiber reinforced carbon material; a ring-shaped outer electrode slidably provided on the outer surface side of the metal-impregnated carbon fiber-reinforced carbon material; and a rod-shaped inner electrode. It has a synchronous drive part that moves the ring-shaped outer electrode so as to surround the tip part of the electrode, and forms a concavo-convex structure of nanometer order on the inner wall surface of the metal-impregnated carbon fiber reinforced carbon material Characterized in that was.

  According to the present invention, since the wall inner peripheral surface of the hermetic container has a concavo-convex structure of the order of nanometers, the wall inner peripheral surface of the hermetic container has a contact angle with the working fluid of almost 0 degrees, and the wettability is very high. As a result, the heat transport capability of the working fluid can be sufficiently increased.

1 is a partially cutaway perspective view showing a first embodiment of a heat pipe according to the present invention. It is a scanning electron microscope (SEM) photograph of the wall inner peripheral surface of the airtight container of FIG. It is a flowchart which shows the manufacturing method of the heat pipe of FIG. It is a figure which shows the plasma etching apparatus used for step 306 of FIG. 4A and 4B show the internal electrodes of FIG. 4, in which FIG. 4A is an overall perspective view, and FIG. FIG. 5 is a partially cutaway perspective view for explaining nanometer-order concavo-convex processing on the inner peripheral surface of the wall of the hermetic container by the plasma etching apparatus of FIG. 4, and (A), (B), and (C) show time series. . It is a partially cutaway perspective view showing a second embodiment of a heat pipe according to the present invention. It is a partially cutaway perspective view which shows 3rd Embodiment of the heat pipe which concerns on this invention. It is a partially cutaway perspective view which shows 4th Embodiment of the heat pipe which concerns on this invention. It is a perspective view which shows the application example of the heat pipe of FIG. It is a partially cutaway perspective view showing a first conventional heat pipe. The 2nd conventional heat pipe is shown, (A) is an outline view and (B) is a BB line sectional view of (A). It is a figure which shows a wettability evaluation apparatus, (A) is an external view, (B) is an enlarged view of the solid and fluid of (A) for demonstrating a contact angle.

  FIG. 1 is a partially cutaway perspective view showing a first embodiment of a heat pipe according to the present invention.

  As shown in FIG. 1, the heat pipe is composed of a cylindrical airtight container 1 for containing a working fluid (not shown) that can be evaporated and condensed within an operating temperature range. The size of the airtight container 1 is, for example, about 4 mm in inner diameter, 6 mm in outer diameter, and about 150 mm in length. The airtight container 1 includes a cylindrical portion 11 and circular lid portions 12 a and 12 b that close the cylindrical portion 11. Also in FIG. 1, R1 indicates a heat receiving evaporation region, and R2 indicates a heat radiation condensation region.

  The cylindrical portion 11 and the lid portions 12a and 12b are made of a metal-impregnated carbon fiber reinforced carbon material. In this case, the carbon content of the metal-impregnated carbon fiber reinforced carbon material is, for example, about 40% inside the wall of the airtight container 1. On the other hand, it is as high as 60% or more on the wall inner peripheral surface side of the airtight container 1. A nanometer-order concavo-convex structure NS as shown in FIG. 2 is formed on the inner peripheral surface of the hermetic container 1. The nanometer order indicates a range of about 10 to 500 nm.

  The nanometer-order concavo-convex structure NS on the inner peripheral surface of the hermetic container 1 has a contact angle with respect to the working fluid of approximately 0 °, and thus exhibits good wettability. As a result, the heat transfer rate from the wall inner peripheral surface of the airtight container 1 to the working fluid is increased. Therefore, the endothermic evaporation rate in the heat receiving evaporation region R1 and the heat dissipation condensation rate in the heat dissipation condensation region R2 are increased, and the heat transport capability can be increased.

  In FIG. 1, the metal-impregnated carbon fiber reinforcement of the hermetic container 1 is increased by the increase in the heat transfer rate from the inner peripheral surface of the hermetic container 1 to the working fluid due to the nanometer-order uneven structure NS of the hermetic container 1. The orientation direction of the carbon material can be a direction perpendicular to the wall of the airtight container 1 and a parallel direction of the wall. For example, the ratio of the vertical orientation and the parallel orientation of the wall of the airtight container 1 of the metal-impregnated carbon fiber reinforced carbon material is 70% to 80%: 30% to 20%. As a result, the internal pressure of the working fluid can be counteracted, so that the reinforcing member 1203 in FIG. 12 is not necessary. However, even if almost 100% of the orientation direction of the metal-impregnated carbon fiber reinforced carbon material of the hermetic container 1 is set to be perpendicular to the wall of the hermetic container 1, if the amount of metal impregnation of the metal-impregnated carbon fiber reinforced carbon material is increased. Since the internal pressure of the working fluid can be counteracted, the reinforcing member 1203 in FIG. 12 is also unnecessary.

  Next, a method for manufacturing the heat pipe of FIG. 1 will be described with reference to FIGS. 3, 4, and 5.

  First, referring to the film-like carbon skeleton-containing plastic cylindrical forming step 301 in FIG. 3, the film-like carbon skeleton-containing plastic is rolled into a cylindrical shape. For example, the plastic is polyimide resin or the like. Moreover, carbon fiber is contained in the film-like polyimide resin, for example, carbon fiber in the shape of a network. Since the carbon fibers are meshed, the orientation of the metal-impregnated carbon fiber reinforced carbon material is the orientation in the vertical direction and the parallel direction of the wall of the hermetic container 1.

  Next, referring to the firing step 302 of FIG. 3, the cylindrical film-like carbon skeleton-containing plastic is fired. As a result, the plastic is burned out and a large number of pores are generated between the carbon fiber skeletons.

  Next, referring to the carbon solvent immersion step 303 in FIG. 3, the inner peripheral surface of the cylindrical carbon fiber skeleton is immersed in a solvent containing carbon, such as an epoxy resin or an acrylic resin.

  Next, referring to the unbaking step 304 of FIG. 3, unbaking is performed at a high temperature, for example, 1000 ° C. for 1-2 hours. Thereby, the carbon content rate of the inner peripheral surface of the cylindrical carbon fiber skeleton becomes higher than the internal carbon content rate. For example, the carbon content inside the cylindrical carbon fiber skeleton is about 40%, whereas the carbon content on the inner peripheral surface of the cylindrical carbon fiber skeleton is 60% or more, for example, 90% to 100%. Thereby, an inner surface high carbon content cylindrical carbon fiber skeleton is obtained.

  Next, referring to the molten metal impregnation step 305 in FIG. 3, a metal such as copper, silver or aluminum is heated to its melting point or higher to be melted, and the inner surface has a high carbon content of cylindrical carbon under an environment of high pressure, for example, 100 atmospheres. The molten metal is impregnated from the outer peripheral surface side of the fiber skeleton. Thereby, molten metal penetrate | invades into the void | hole inside a cylindrical carbon fiber frame | skeleton, and an inner surface high carbon content cylindrical metal impregnation carbon fiber reinforced carbon material is obtained. Silicon may be used in place of the above metal. Since the viscosity at the time of melting of silicon is small, it can be impregnated without being in a high pressure environment. Although silicon is non-metallic, in the present invention, it is treated as a metal.

  Next, referring to the plasma etching step 306 of FIG. 3, the inner surface of the inner high carbon content cylindrical metal-impregnated carbon fiber reinforced carbon material is plasma etched to form the inner surface high carbon content cylindrical metal impregnated carbon fiber reinforced carbon material. An uneven structure NS of nanometer order is formed on the inner surface.

  3 is executed by the plasma etching apparatus shown in FIG.

In FIG. 4, two inner surfaces of a vacuum chamber 402 formed of aluminum or the like as a work material 401 using a cylindrical metal-impregnated carbon fiber reinforced carbon material having an inner high carbon content obtained in the molten metal impregnation step 305 of FIG. The support bases 403 and 404 are sandwiched and fixed. The support bases 403 and 404 are formed of an insulating material, and the support bases 403 and 404 are provided with small recesses (not shown) for fitting the workpiece 401. The support base 403 is provided with a gas inlet 403a for introducing Ar / O ₂ gas into the vacuum chamber 402. In this case, the inner diameter of the gas inlet 403a is substantially the same as the inner diameter of the workpiece 401. Has been. On the other hand, a gas discharge port 402 a connected to a vacuum pump (not shown) is provided below the vacuum chamber 402. As a result, the Ar / O ₂ gas introduced from the gas inlet 403a passes through the inner peripheral surface side of the wall of the workpiece 401 and is discharged from the gas outlet 402a.

  In order to process the inner peripheral surface of the workpiece 401, a pair of discharge electrodes, that is, an inner electrode 405 and an outer electrode 406 are provided inside and outside the workpiece 401. The inner electrode 405 is slidably supported by the vacuum chamber 402 by an insulating member 405a, while the outer electrode 406 is slidably supported by the workpiece 401 and fixed to the outer electrode support 407. The inner electrode 405 is connected to the high frequency power source 407 and functions as an anode electrode, while the outer electrode 406 is grounded via the outer electrode support 406a and the vacuum chamber 402 and functions as a cathode electrode.

  The inner electrode 405 and the outer electrode 406 are simultaneously moved at the same speed by the synchronous driving unit 408.

  5A and 5B show the inner electrode 405 of FIG. 4, in which FIG. 5A is an overall perspective view, and FIG. 5B is a front end perspective view.

  As shown in FIG. 5, the inner electrode 405 has a rod shape, and its diameter is smaller than the diameter of the workpiece 401 and its length is longer than the entire length of the workpiece 401. The tip of the inner electrode 405 has a plurality of protrusions, and is uniformly arranged over the entire 360 ° circumference in order to perform plasma etching uniformly.

  On the other hand, the outer electrode 406 has a ring shape and is provided so as to surround the tip of the inner electrode 405. At this time, the inner electrode 405 is further finely oscillated or rotated, thereby preventing the deviation of the plasma generation position and performing the plasma etching uniformly over the circumferential direction of the workpiece 401. .

The plasma etching apparatus of FIG. 4 is operated under the following conditions, for example.
Ultimate vacuum: 6.65Pa (50mTorr)
O ₂ gas flow rate: 100sccm
Ar gas flow rate: 50sccm
Input power: 500W
Processing time: 1-2 minutes (per 1 cm ² )
At this time, the outer electrode 406 is moved so as to surround the tip of the inner electrode 405 as shown in FIG. As a result, plasma is generated only between the inner electrode 405 and the outer electrode 406, and the inner peripheral surface of the wall of the workpiece 401 has a concavo-convex structure NS on the order of nanometers.

The plasma etching method in step 306 in FIG. 3 may be any of electron cyclotron resonance (ECR) etching method, reactive ion etching (RIE) method, atmospheric pressure plasma etching method, etc. / O ₂ O ₂ gas other than the gas, CO ₂ gas, CF ₄ gas, may be any of such SF ₄ gas.

  Next, referring to the working fluid sealing step 307 in FIG. 3, a working fluid, for example, pure water vapor, is sealed in a cylindrical metal-impregnated carbon fiber reinforced carbon material having a concavo-convex structure NS having an inner surface on the order of nanometers.

  Finally, referring to the lid joining step 308 of FIG. 3, a cylindrical metal-impregnated carbon fiber having a concave and convex structure NS with an inner surface in which the working fluid is sealed in the disc-like lids 12a and 12b manufactured separately. Join to both ends of reinforced carbon material. In this case, the lid portions 12a and 12b are formed with a concavo-convex structure on the order of nanometers as in the workpiece 401. However, the lid portions 12a and 12b are not necessarily made of a metal-impregnated carbon fiber reinforced carbon material, and may be a carbon substrate. . In addition, it is preferable to use solder or brazing material in consideration of thermal conductivity. Furthermore, in order to ensure the airtightness of the heat pipe, the concavo-convex structure at the joint portion of the lid portions 12a and 12b may be scraped off as necessary.

  FIG. 7 is a partially cutaway perspective view showing a second embodiment of the heat pipe according to the present invention.

  As shown in FIG. 7, the heat pipe includes a hexagonal columnar airtight container 2. The size of the airtight container 2 is, for example, about 3 mm on a side and about 150 mm in length. The airtight container 2 includes a hexagonal column portion 21 and hexagonal lid portions 22a and 22b that close the hexagonal column portion 21. Also in FIG. 7, R1 indicates a heat receiving evaporation region, and R2 indicates a heat radiation condensation region.

  The hexagonal columnar airtight container 2 is less likely to be etched at the corners than the airtight container 1 of FIG. Has the advantage of being suitable.

  The heat pipe manufacturing method of FIG. 7 includes a film-like carbon fiber reinforced plastic hexagonal column forming step instead of the film-like carbon fiber reinforced plastic cylindrical forming step 301 of FIG. Thus, the film-like carbon fiber reinforced plastic is folded into a hexagonal column shape. The subsequent steps are the same as steps 302 to 308 in FIG.

  FIG. 8 is a partially cutaway perspective view showing a third embodiment of the heat pipe according to the present invention.

  In the airtight container 3 of FIG. 8, a heat sink 13 having a length of about 40 mm is integrally formed in the heat radiation condensing region R2 of the airtight container 1 of FIG. In this case, the heat sink 13 is also made of a metal-impregnated carbon fiber reinforced carbon material, and the orientation direction thereof is parallel to each surface of the heat sink 13.

  8, between the plasma etching step 306 and the working fluid sealing step 307 in FIG. 3, the cylindrical inner metal impregnated carbon fiber reinforced carbon material and the heat sink of the airtight container 3 are interposed between the plasma etching step 306 and the working fluid sealing step 307. The baking process for fitting 13 and carrying out integral molding is performed. Thereby, it is excellent in unity rather than joining with heat conductive grease etc., Therefore, heat conductivity is excellent.

  FIG. 9 is a partially cutaway perspective view showing a fourth embodiment of a heat pipe according to the present invention.

  In the airtight container 4 of FIG. 9, radial fins 14 having a length of about 50 mm are integrally formed in the heat radiation condensation region R2 of the airtight container 1 of FIG. In this case, the radial fins 14 are also made of a metal-impregnated carbon fiber reinforced carbon material, and the orientation direction thereof is parallel to each surface of the radial fins 14. Further, since the fins of the radial fins 14 are symmetric with respect to the hermetic container 4, the heat diffusion to the fins is uniform, and as a result, the heat dissipation capability of each fin can be utilized to the maximum.

  In the heat pipe manufacturing method of FIG. 9, between the plasma etching process 306 and the working fluid sealing process 307 of FIG. A firing process for fitting the fins 14 and integrally forming them is performed. Thereby, it is excellent in unity rather than joining with heat conductive grease etc., Therefore, heat conductivity is excellent.

  FIG. 10 is a perspective view showing an application example of the airtight container 4 of FIG.

  In FIG. 10, the axial fan 5 is made to oppose the radial fin 14 of the airtight container 4 of FIG. That is, it can be understood that the arrangement of the fins of the radial fins 14 is point-symmetric, so that the compatibility with the axial fan 5 is good. That is, the peripheral portion where the airflow of the axial flow fan 5 is large can correspond to each fin of the radial fins 14.

  When a semiconductor device is mounted as a heat generation source in the heat receiving evaporation region R1 of the airtight containers 1, 2, 3, 4 described above, it may be mounted via an adapter made of a metal-impregnated carbon fiber reinforced carbon material. Further, when one semiconductor chip or one light emitting diode (LED) chip is attached as a heat source, it may be attached directly to the lid portion 12a (22a).

  Furthermore, the cylindrical part 11 and the hexagonal column part 21 of the above-mentioned airtight containers 1, 2, 3, and 4 may have other cylindrical shapes such as a polygonal column.

1, 2, 3, 4: Airtight container 11: Cylindrical portion 12a, 12b: Lid 21: Hexagonal column 22a, 22b: Lid 401: Work material 402: Vacuum chamber 402a: Gas outlet 403: Support base 403a: Gas inlet 404: Support base 405: Inner electrode 406: Outer electrode
407: High frequency power supply
408: Synchronous drive unit NS: Concave and convex structure

Claims (8)

In a heat pipe comprising an airtight container for containing a working fluid capable of evaporating and condensing within an operating temperature range,
The airtight container is made of a metal-impregnated carbon fiber reinforced carbon material,
The carbon content of the metal-impregnated carbon fiber reinforced carbon material is higher on the inner peripheral surface side than the inside of the wall of the airtight container,
A heat pipe, wherein a concavo-convex structure of nanometer order is formed on the inner peripheral surface of the metal-impregnated carbon fiber reinforced carbon material.   The heat pipe according to claim 1, wherein an orientation direction of the metal-impregnated carbon fiber reinforced carbon material is a direction perpendicular to a wall of the airtight container.   The heat pipe according to claim 1, wherein an orientation direction of the metal-impregnated carbon fiber reinforced carbon material is a direction perpendicular to and parallel to a wall of the airtight container.   The heat pipe according to claim 1, wherein the heat radiation condensation region of the airtight container is fitted to a heat sink and integrally formed. The heat pipe according to claim 1, wherein the heat radiation condensing region of the airtight container is integrally formed with a radial fin. A forming step of forming a film-like carbon skeleton-containing plastic containing carbon fibers in a network shape into a cylindrical shape;
A firing step of firing the film-like carbon skeleton-containing plastic to produce a carbon fiber skeleton having a large number of pores;
A carbon solvent immersing step of immersing the inner peripheral surface of the carbon fiber skeleton in a solvent containing carbon;
An unglazed step of unfiring the carbon fiber skeleton after the carbon solvent immersion step;
A step of impregnating the carbon fiber skeleton with a molten metal after the uncoating step to produce an inner surface high carbon content metal impregnated carbon fiber reinforced carbon material;
A plasma etching step of plasma etching the inner surface of the inner surface high carbon content metal-impregnated carbon fiber reinforced carbon material to form a concavo-convex structure of nanometer order on the inner surface;
After the plasma etching step, a working fluid enclosing step of enclosing a working fluid inside the inner high carbon content metal impregnated carbon fiber reinforced carbon material,
And a step of joining lids to both ends of the inner surface high carbon content metal-impregnated carbon fiber reinforced carbon material after the working fluid enclosing step. An airtight container for containing a working fluid capable of evaporating and condensing within an operating temperature range is made of a metal-impregnated carbon fiber reinforced carbon material,
In the plasma etching apparatus for a heat pipe, the carbon content of the metal-impregnated carbon fiber reinforced carbon material is higher on the inner peripheral surface side than the inside of the wall of the airtight container.
A support for supporting the metal-impregnated carbon fiber-reinforced carbon material having a high carbon content on the inner surface;
A rod-like inner electrode slidably provided on the inner surface side of the metal-impregnated carbon fiber reinforced carbon material,
A ring-shaped outer electrode slidably provided on the outer surface side of the metal-impregnated carbon fiber-reinforced carbon material;
And a synchronous drive unit that moves the ring-shaped outer electrode so as to surround the tip of the rod-shaped inner electrode, and formed a concavo-convex structure of nanometer order on the inner wall surface of the metal-impregnated carbon fiber reinforced carbon material A plasma etching apparatus characterized by that. The plasma etching apparatus according to claim 7, wherein a plurality of protrusions are provided at a tip portion of the rod-shaped inner electrode.