Preparation method for heat pipe

Abstract

Methods for preparing a heat pipe are provided. The methods may include forming a metal foam on a surface of a first metal sheet using a slurry, placing the first metal sheet on a second metal sheet, and bonding outer portions of the first and second metal sheets. The surface of the first metal sheet faces the second metal sheet.

Claims

1. A method for preparing a heat pipe, the method comprising: forming a metal foam directly on a surface of a first metal sheet using a slurry, wherein the slurry comprises metal powder, a binder, and a dispersant; placing the first metal sheet on a second metal sheet, wherein the surface of the first metal sheet faces the second metal sheet; and bonding outer portions of the first and second metal sheets, wherein forming the metal foam directly on the surface of the first metal sheet comprises forming a metal foam precursor on the surface of the first metal sheet by applying the slurry directly onto the surface of the first metal sheet, and wherein the slurry is devoid of a blowing agent.

2. The method of claim 1, wherein forming the metal foam directly on the surface of the first metal sheet further comprises sintering the metal foam precursor.

3. The method of claim 2, wherein the metal foam precursor is formed in the form of a film or sheet.

4. The method of claim 2, wherein the sintering is performed at a temperature in a range of 500° C. to 2000° C.

5. The method of claim 2, wherein forming the metal foam precursor comprises coating the slurry on the surface of the first metal sheet, and wherein the method further comprises performing a drying process after forming the metal foam precursor and before sintering the metal foam precursor.

6. The method of claim 5, wherein the drying process is performed at a temperature in a range of 50° C. to 250° C.

7. The method of claim 1, wherein the slurry comprises 1 to 500 parts by weight of the binder relative to 100 parts by weight of the metal powder, and 10 to 2,000 parts by weight of the dispersant relative to 100 parts by weight of the binder.

8. The method of claim 1, wherein the metal powder has an average particle diameter in a range of 0.1 μm to 200 μm.

9. The method of claim 1, wherein the binder is alkyl cellulose, polyalkylene carbonate or a polyvinyl alcohol-based binder.

10. The method of claim 1, wherein the dispersant is an alcohol.

11. The method of claim 1, wherein the slurry further comprises a solvent.

12. The method of claim 1, wherein the metal foam comprises a first metal foam, and wherein the method further comprises forming a second metal foam directly on a surface of the second metal sheet, wherein the surface of the second metal sheet faces the first metal sheet.

13. The method of claim 1 wherein the metal foam has a porosity in a range of 60% to 99%.

14. The method of claim 1, wherein the metal foam has a pore size in a range of 100 nm to 100 μm.

15. The method of claim 1, wherein the metal foam has a thickness of 500 μm or less.

16. The method of claim 1, wherein the heat pipe has a thickness in a range of 0.06 mm to 0.8 mm.

17. The method of claim 1, wherein the metal powder comprises conductive magnetic metal powder.

18. The method of claim 1, wherein the metal powder comprises at least one of powder of nickel, iron and cobalt.

19. The method of claim 1, wherein the first metal sheet further comprises an inner portion between the outer portions, and the metal foam is formed on the inner portion of the first metal sheet and is not formed on the outer portions of the first metal sheet.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a view showing an exemplary shape of a metal foam-attached metal sheet of the present application.

(2) FIG. 2 is a SEM photograph of the metal foam formed in an example.

(3) FIG. 3 is a view exemplarily showing a preparation method of the present application.

MODE FOR INVENTION

(4) Hereinafter, the present application will be described in detail by way of examples and comparative examples, but the scope of the present application is not limited to the following examples.

Example 1

(5) Preparation of First Metal Sheet

(6) A slurry was prepared using copper (Cu) powder having an average particle diameter (D50 particle diameter) of about 10 μm to 20 μm as a metal component. The copper powder was mixed with a mixture in which ethylene glycol (EG) as a dispersant and ethyl cellulose (EC) as a binder were mixed in a weight ratio (EG:EC) of 4:5, so that the weight ratio (Cu:EC) of the copper powder to the binder was about 10:1, thereby preparing a slurry. The slurry was coated on a copper base material in the form of a film and dried at about 120° C. for about 1 hour to form a metal foam precursor. At this time, the thickness of the coated metal foam precursor was about 100 The sintering was performed to prepare copper foam by applying an external heat source in an electric furnace so that the precursor was maintained at a temperature of about 1000° C. in a hydrogen/argon gas atmosphere for 2 hours. The porosity of the prepared sheet-shaped copper foam was about 65%. FIG. 2 is a SEM photograph showing a metal foam layer on the copper base material formed as above.

(7) Preparation of Second Metal Sheet

(8) A slurry was prepared in the same manner as in the case of the first metal sheet, except that terpineol was used instead of ethylene glycol as a dispersant and polyvinyl acetate (PVAc) was used instead of ethyl cellulose (EC) as a binder. Upon preparing the slurry, the formulation ratio of the copper powder, the dispersant and the polyvinyl acetate was 1:1:0.1 (Cu:terpineol:PVAc) on the basis of weight. The slurry was coated on a copper base material to a thickness of about 30 μm in a film shape and dried in the same manner as in the case of the first metal sheet to form a metal foam precursor on the copper base material. Subsequently, the sintering was performed under the same conditions as in the case of the first metal sheet to form the copper foam integrated with the copper base material. The porosity of the prepared copper foam was about 68%, which was integrated with the copper substrate with excellent adhesion.

(9) Preparation of Heat Pipe

(10) The first and second metal sheets 11a and 11b as prepared in the above were arranged so that the metal foam layers 12 on their surfaces faced each other, and as shown in FIG. 3, the peripheral parts 11c were press-welded to prepare a heat pipe.