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 a metal foam comprising uniformly formed pores and having excellent mechanical properties as well as the desired porosity, and a metal foam having the above characteristics. 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, within a fast process time, and such a metal foam.

Claims

1. A method for manufacturing a metal foam comprising applying an electromagnetic field to a green structure formed by using a slurry comprising a metal component comprising a conductive metal having a relative magnetic permeability of 90 or more or an alloy comprising the conductive metal, a solvent, and a polymer powder having a solubility in the solvent of 5 mg/mL at room temperature to sinter the green structure and form the metal foam.

2. The method for manufacturing a metal foam according to claim 1, wherein the conductive metal is any one selected from the group consisting of iron, nickel and cobalt.

3. The method for manufacturing a metal foam according to claim 1, wherein the metal component comprises, on the basis of weight, 50 wt % or more of the conductive metal or the alloy containing the conductive metal.

4. The method for manufacturing a metal foam according to claim 1, wherein the metal component has an average particle diameter in a range of 5 to 100 μm.

5. The method for manufacturing a metal foam according to claim 1, wherein the solvent has a dielectric constant in a range of 10 to 120.

6. The method for manufacturing a metal foam according to claim 1, wherein the solvent is water, alcohol, dimethylsulfoxide, dimethylformamide or N-alkylpyrrolidone.

7. The method for manufacturing a metal foam according to claim 1, wherein the solvent is contained in the slurry at a ratio of 50 to 300 parts by weight relative to 100 parts by weight of the metal component

8. The method for manufacturing a metal foam according to claim 1, wherein the polymer powder is an alkyl cellulose, polyalkylene carbonate or polyvinyl alcohol.

9. The method for manufacturing a metal foam according to claim 1, wherein the polymer powder is contained in the slurry at a ratio of 10 to 100 parts by weight relative to 100 parts by weight of the metal component.

10. The method for manufacturing a metal foam according to claim 1, wherein the slurry further comprises a binder having a solubility in the solvent of 100 mg/mL or more at room temperature.

11. The method for manufacturing a metal foam according to claim 10, wherein the binder is an alkyl cellulose, polyalkylene carbonate or polyvinyl alcohol.

12. The method for manufacturing a metal foam according to claim 10, wherein the binder is contained in the slurry at a ratio of 1 to 15 parts by weight relative to 100 parts by weight of the metal component.

13. The method for manufacturing a metal foam according to claim 1, wherein applying the electromagnetic field comprises applying a current in a range of 100 A to 1,000 A.

14. The method for manufacturing a metal foam according to claim 1, wherein the metal foam has a porosity in a range of about 40% to 99%.

15. The method for manufacturing a metal foam according to claim 1, wherein the metal foam has a porosity greater than 80%.

16. The method for manufacturing a metal foam according to claim 1, wherein the green structure is formed by coating the slurry on a plate.

17. The method for manufacturing a metal foam according to claim 16, wherein the green structure is a film having a thickness of 300 μm or less.

18. The method for manufacturing a metal foam according to claim 1, further comprising applying heat to the green structure while applying the electromagnetic field to the green structure.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0036] FIG. 1 is a photograph of the sheet produced in Example.

MODE FOR INVENTION

[0037] 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

[0038] Nickel having a conductivity of about 14.5 MS/m at 20° C. and a relative magnetic permeability of about 600 was used as a metal component. The nickel powder having an average particle diameter in a range of about 5 to 10 μm was blended with water as a solvent, and methyl cellulose and ethyl cellulose to prepare a slurry. Here, the solubility of methyl cellulose in the water is about 180 mg/mL at room temperature, and the solubility of ethyl cellulose in the water is about 1 mg/mL at room temperature. Upon preparing the slurry, the weight ratio of nickel powder, water, methyl cellulose and ethyl cellulose (nickel powder: water: methyl cellulose: ethyl cellulose) was set as about 2.8:2.7:0.3:1. The slurry was coated on a quartz plate in the form of a film to form a green structure. Subsequently, the green structure was dried at a temperature of about 110° C. for about 30 minutes and then an electromagnetic field was applied to the green structure with a coil-type induction heater. The electromagnetic field 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 5 minutes. After the application of the electromagnetic field, the sintered green structure was put into water and subjected to sonication cleaning to produce a nickel sheet having a thickness of about 130 μm in the form of a film. A photograph of the produced sheet was shown in FIG. 1. The produced nickel sheet had a porosity of about 82% and a tensile strength of about 3.4 MPa.

EXAMPLE 2

[0039] A nickel sheet having a thickness of about 120 μm in the form of a film was produced in the same manner as in Example 1, except that a nickel powder having an average particle diameter in a range of about 30 to 40 μm was used as the metal component and upon preparing the slurry, a weight ratio of nickel powder, water, methyl cellulose and ethyl cellulose (nickel powder: water: methyl cellulose: ethyl cellulose) was set as 2.8:2.7:0.3:1. The produced nickel sheet had a porosity of about 81% and a tensile strength of about 4.1 MPa.