Preparation method for metal foam

Abstract

Provided herein are methods of preparing a metal foam that include the steps of forming a metal foam precursor with a slurry comprising a metal component, a dispersant, a binder and an antisolvent, and sintering the metal foam precursor. Such methods may provide metal foams having various pore sizes. Methods further include forming a thin metal foam on a base material.

Claims

1. A method for preparing a metal foam, the method comprising: forming a metal foam precursor with a slurry that comprises a metal powder, a dispersant, a binder and an antisolvent for the binder, wherein the antisolvent for the binder is miscible with the dispersant, and a weight ratio of the dispersant and the antisolvent (dispersant/antisolvent) is in a range of 0.5 to 20; and sintering the metal foam precursor, wherein the dispersant is an alcohol having 9 to 20 carbon atoms, wherein the antisolvent is one or more antisolvents selected from the group consisting of a monovalent aliphatic alcohol having 1 to 8 carbon atom(s), an alkanolamine, an alkyl ether, an aryl ether, an ester, a ketone, an alkylbenzene, an arylbenzene, and a halobenzene.

2. The method for preparing the metal foam according to claim 1, wherein the slurry comprises 45 wt % or more of the metal powder.

3. The method for preparing the metal foam according to claim 1, wherein the binder is alkyl cellulose, polyalkylene carbonate, polyvinyl alcohol or polyvinyl acetate.

4. The method for preparing the metal foam according to claim 1, wherein the slurry comprises the binder in a range of 1 to 500 parts by weight relative to 100 parts by weight of the metal powder.

5. The method for preparing the metal foam according to claim 2, wherein the slurry comprises the dispersant in a range of 30 to 2,000 parts by weight relative to 100 parts by weight of the binder.

6. The method for preparing the metal foam according to claim 2, wherein the slurry comprises the antisolvent for the binder in a range of 50 to 500 parts by weight relative to 100 parts by weight of the binder.

7. The method for preparing the metal foam according to claim 1, wherein the dispersant and the antisolvent for the binder are present in the slurry at a total weight in a range of 10 to 1,000 parts by weight relative to 100 parts by weight of the metal powder.

8. The method for preparing the metal foam according to claim 1, wherein the metal foam comprises one or more pores, and wherein the one or more pores have a size in a range of 0.1 μm to 200 μm.

9. The method for preparing the metal foam according to claim 1, wherein a porosity of the metal foam is in a range of 30% to 90%.

10. The method for preparing the metal foam according to claim 1, wherein the metal foam is in the form of a film or sheet.

11. The method for preparing the metal foam according to claim 10, wherein the film or sheet has a thickness of 500 μm or less.

12. The method for preparing the metal foam according to claim 1, wherein forming the metal foam precursor further comprises drying the slurry before sintering the metal foam precursor.

13. The method for preparing the metal foam according to claim 12, wherein drying the slurry is performed at a temperature in a range of 20° C. to 250° C.

14. The method for preparing the metal foam according to claim 1, wherein sintering is performed in an atmosphere including hydrogen and argon.

15. The method for preparing the metal foam according to claim 1, wherein the metal powder comprises copper powder.

16. The method for preparing the metal foam according to claim 1, wherein sintering is performed by induction heating.

17. The method for preparing the metal foam according to claim 1, wherein the slurry comprises the binder in a range of 1 to 20 parts by weight relative to 100 parts by weight of the metal powder; and the dispersant in a range of 500 to 1,500 parts by weight relative to 100 parts by weight of the binder.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a scanning electron micrograph of the metal foam prepared in Example 1.

(2) FIG. 2 is a scanning electron micrograph of the metal foam prepared in Comparative Example 1.

(3) FIG. 3 is a view showing pore size distributions of the metal foams prepared in Examples and Comparative Example.

MODE FOR INVENTION

(4) Hereinafter, the present application will be described by way of Examples and Comparative Examples, but the scope of the present application is not limited to the following Examples.

EXAMPLE 1

(5) Copper powder having an average particle diameter (D50) in a range of about 10 to 20 μm, a binder (polyvinyl acetate), a dispersant (alpha-terpineol) and an antisolvent (isopropanol) were combined in a weight ratio of about 5:0.5:4.05:0.45 (copper powder: binder: dispersant: antisolvent) to prepare a slurry. The slurry was coated in a film form and dried at about 100° C. for about 2 hours to form a metal foam precursor. At this time, the thickness of the coated metal foam precursor was about 200 μm or so. An external heat source was applied in an electric furnace so that the precursor was maintained at a temperature of about 900° C. for 2 hours in a hydrogen/argon gas atmosphere, and sintering was performed to prepare a copper foam. The porosity of the prepared copper foam in the form of a sheet was a level of about 76% or so. FIG. 1 is a photograph of the metal foam formed in Example 1.

EXAMPLE 2

(6) Copper powder having an average particle diameter (D50) in a range of about 10 to 20 μm, a binder (polyvinyl acetate), a dispersant (alpha-terpineol) and an antisolvent (isopropanol) were combined in a weight ratio of about 5:0.5:3.15:1.35 (copper powder: binder: dispersant: antisolvent) to prepare a slurry. The slurry was coated in a film form and dried at about 100° C. for about 2 hours to form a metal foam precursor. At this time, the thickness of the coated metal foam precursor was about 200 μm or so. An external heat source was applied in an electric furnace so that the precursor was maintained at a temperature of about 900° C. for 2 hours in a hydrogen/argon gas atmosphere, and sintering was performed to prepare a copper foam. The porosity of the prepared copper foam in the form of a sheet was a level of about 78% or so.

Comparative Example 1

(7) Copper powder having an average particle diameter (D50) in a range of about 10 to 20 μm, a binder (polyvinyl acetate) and a dispersant (alpha-terpineol) were combined in a weight ratio of about 5:0.5:4.5 (copper powder: binder: dispersant) to prepare a slurry. The slurry was coated in a film form and dried at about 100° C. for about 2 hours to form a metal foam precursor. At this time, the thickness of the coated metal foam precursor was about 200 μm or so. An external heat source was applied in an electric furnace so that the precursor was maintained at a temperature of about 900° C. for 2 hours in a hydrogen/argon gas atmosphere, and sintering was performed to prepare a copper foam. The porosity of the prepared copper foam in the form of a sheet was a level of about 74% or so. FIG. 2 is a photograph of the prepared metal foam.

(8) From the comparison of FIGS. 1 and 2, it can be confirmed that the pore size of the metal foam has been increased even under similar levels of porosity through the application of the antisolvent. FIG. 3 is pore size distributions of the metal foams of Examples 1 and 2 and Comparative Example 1, where it can be confirmed that the pore size of the metal foam can be controlled even under similar levels of porosity by using the antisolvent and also adjusting the amount thereof.