METHOD FOR MANUFACTURING METAL FOAM

Abstract

The present application provides a method for manufacturing a metal foam. The present application can provide a method for manufacturing a metal foam, which is capable of forming in a very short time a metal foam comprising uniformly formed pores and having excellent mechanical properties as well as the desired porosity, and a metal foam produced by the above method. In addition, the present application can provide a method capable of forming a metal foam in which the above-mentioned physical properties are ensured, while being in the form of a thin film or sheet, in a short time, and such a metal foam.

Claims

1. A method for manufacturing a metal foam, the method comprising: applying an electromagnetic field to a green structure comprising a polymer foam, said polymer foam comprising a surface with a layer of a metal component, and said metal component comprising a conductive metal having a relative magnetic permeability of 90 or more; and sintering the metal component with heat generated by induction heating of the conductive metal, to thereby manufacture the metal foam.

2. The method for manufacturing a metal foam according to claim 1, wherein the polymer foam is a polyurethane foam, an acrylic foam, a polystyrene foam, a polyolefin foam, a polycarbonate foam, or a polyvinyl chloride foam.

3. The method for manufacturing a metal foam according to claim 1, wherein the conductive metal has a conductivity of 8 MS/m or more at 20 C.

4. The method for manufacturing a metal foam according to claim 1, wherein the conductive metal is nickel, iron or cobalt.

5. The method for manufacturing a metal foam according to claim 1, wherein the metal component comprises 30 wt % or more of the conductive metal.

6. The method for manufacturing a metal foam according to claim 1, wherein the conductive metal is in the form of powder with an average particle diameter in a range of 10 to 100 m.

7. The method for manufacturing a metal foam according to claim 1, wherein the green structure is formed by spraying the metal component on the polymer foam or plating the metal component on the polymer foam.

8. The method for manufacturing a metal foam according to claim 1, wherein the induction heating comprises a first induction heating, and a second induction heating performed under conditions different from the first induction heating.

9. The method for manufacturing a metal foam according to claim 8, wherein in the first induction heating, a first electromagnetic field is formed by applying a current in a range of 100 to 500 A.

10. The method for manufacturing a metal foam according to claim 8, wherein in the first induction heating, a first electromagnetic field is formed by applying a current at a frequency in a range of 200 to 500 kHz.

11. The method for manufacturing a metal foam according to claim 8, wherein in the first induction heating, a first electromagnetic field is applied for a time in a range of 30 seconds to 1 hour.

12. The method for manufacturing a metal foam according to claim 8, wherein in the second induction heating, a second electromagnetic field is formed by applying a current in a range of 100 A to 1,000 A.

13. The method for manufacturing a metal foam according to claim 8, wherein in the second induction heating, a second electromagnetic field is formed by applying a current at a frequency in a range of 100 kHz to 1,000 kHz.

14. The method for manufacturing a metal foam according to claim 8, wherein in the second induction heating, a second electromagnetic field is applied for a time in a range of 1 minute to 10 hours.

15. The method for manufacturing a metal foam according to claim 1, wherein the polymer foam decomposes during said sintering.

16. The method for manufacturing a metal foam according to claim 1, wherein the polymer foam is in the form of a film or sheet, and the metal foam produced is in the form of a film or sheet.

17. The method for manufacturing a metal foam according to claim 1, wherein the metal foam is in the form of a film or sheet having a thickness of 2,000 m or less.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0042] The present application can provide a method for manufacturing a metal foam, which is capable of forming in a very short time a metal foam comprising uniformly formed pores and having excellent mechanical properties as well as the desired porosity, and a metal foam produced by the above method. In addition, the present application can provide a method capable of forming a metal foam in which the above-mentioned physical properties are ensured, while being in the form of a thin film or sheet, in a short time, and such a metal foam.

MODE FOR INVENTION

[0043] 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

[0044] A polymer foam is a polyurethane foam, which is in the form of a sheet having a thickness of about 5 mm. Titanium was sputtered on the surface of the polyurethane foam by a known method to form a thin film having a thickness of about 100 nm. Then, the polyurethane foam in which the titanium was sputtered on the surface was placed in a solution in which NiSO.sub.4, NiCl.sub.2 or H.sub.2BO.sub.3 and the like was dissolved, and the surface of the relevant polyurethane foam was plated with nickel by an electrolytic plating method in which a platinum electrode and the polyurethane foam were applied as an anode and a cathode, respectively. After the plating was performed for about one hour, the plated polyurethane foam was taken out, and then removal of the polyurethane foam and sintering of nickel were performed by induction heating under an atmosphere of H.sub.2/N.sub.2. The electromagnetic field for induction heating was formed by applying a current of about 350 A at a frequency of about 380 kHz, and the electromagnetic field was applied for about 3 minutes. Through the above steps, a sheet having a thickness of about 4.2 mm in a film form was produced. The produced sheet had a porosity of about 93%. FIG. 1 is a photograph of the metal foam produced in the example.

Example 2

[0045] A metal foam was produced in the same manner as in Example 1, except that an acrylic foam was used as the polymer foam. The produced metal foam in the film form had a thickness of about 4.5 mm and a porosity of about 95%.

Comparative Example 1

[0046] The nickel plated polyurethane foam produced in the same manner as in Example 1 was applied to a resistance heating oven and sintered. It took about 6 hours to produce a metal foam having physical properties similar to those of Example 1 through such a process.