Metal slurry for electrode formation and production method of the same

• US 7,108,733 B2
• Filed: 06/20/2003
• Issued: 09/19/2006
• Est. Priority Date: 06/20/2003
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Enokido, Yasushi
• Primary Examiner(s): MAI, NGOCLAN THI
• Application Number:
  US10/601,272
• Publication Number:
  US 20050016325A1
• Time in Patent Office: 1,187 Days
• Field of Search: 752/52, 252/512, 252/513, 252/514
• US Class Current: 75/252
• CPC Class Codes: B22F 1/00 Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
• CPC Class Codes: B22F 1/0545 Dispersions or suspensions of nanosized particles
• CPC Class Codes: B22F 1/065 Spherical particles
• CPC Class Codes: B22F 1/10 Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H05K 1/097 Inks comprising nanoparticles and specially adapted for being sintered at low temperature H05K1/095 takes precedence
• CPC Class Codes: H05K 2203/013 Inkjet printing, e.g. for printing insulating material or resist using ink-jet printing to form a conductive pattern H05K3/125
• CPC Class Codes: H05K 3/125 by ink-jet printing

Abstract

The present invention provides a metal slurry for electrode formation which slurry is high in dispersion property and enables formation of high density electrode films. The metal slurry for electrode formation is composed of a spherical metal powder of 0.1 to 2.0 μm in mean particle size and a dispersion medium. By making the spherical metal powder have a mean particle size falling within the range from 0.1 to 2.0 μm, there can be obtained a metal slurry for electrode formation which slurry can be coated through a nozzle and is high in dispersion property, without using expensive nanoparticles. In addition, as the dispersion medium, water or lower molecular weight alcohols can be used. Furthermore, the dispersion property can be improved by further adding a dispersant of 10 wt % or below (exclusive of zero) in relation to the metal powder.

Claims

1. A metal slurry for electrode formation, comprising:

a spherical metal powder having a mean particle size of 0.1 to 2.0 μ

m and a tap density of 3.0 g/cc or above; and

a dispersion medium for dispersing said spherical metal powder, present in a volume % content ratio with the powder that is between 1;

99 and 40;

60 (powder;

dispersion medium);

said metal slurry having a sediment density of at least 50%.

2. A metal slurry for electrode formation according to claim 1, wherein said dispersion medium is selected from the group consisting of:

water and lower molecular weight alcohols.

3. A metal slurry for electrode formation according to claim 1, wherein a dispersant is present in an amount of at most 10 wt % (exclusive of zero) in relation to said metal powder.

4. A metal slurry for electrode formation according to claim 1 wherein the viscosity of said metal slurry is at most 20 cps.

5. A metal slurry for electrode formation according to claim 1, wherein said metal powder comprises a silver powder.

6. A metal slurry for electrode formation according to claim 1, wherein said metal slurry is jet printable with a print head.

7. A metal slurry for electrode formation according to claim 6, wherein said metal slurry is jet printable with a continuous jet print head.

8. A production method of a metal slurry for electrode formation, which slurry comprises a mixture of a dispersion medium and a spherical metal powder present in a volume % content ratio that is between 1:

99 and 40;

60 (powder;

dispersion medium); and

has a sediment density of at least 50%, said method comprising the steps of preparing a spherical metal powder of 0.1 to 2.0 pin in mean particle size, having a tap density of 3.0 g/cc or above, and mixing together said metal powder and said dispersion medium.

9. A production method of the metal slurry for electrode formation according to claim 8, wherein said mixing comprises an ultrasonic vibration.

10. A production method of the metal slurry for electrode formation according to claim 8, wherein further addition of a dispersant is made to at least one of said dispersion medium and the mixture comprising said metal powder and said dispersion medium.

11. A production method of a metal slurry according to claim 8, wherein said metal powder comprises a silver powder.

16. A metal slurry for electrode formation according to claim 9, wherein the viscosity of said metal slurry is at most 20 cps.

12. A metal slurry for electrode formation, comprising:

a spherical metal powder having a sphericity of 0.7 to 1.0 and a tap density of 3.0 g/cc or above; and

water as a dispersion medium for dispersing said metal powder, wherein;

said metal slurry has a sediment density of at least 50% and is jet printable with a print head.

13. A metal slurry for electrode formation according to claim 12, wherein said metal powder is produced by a reduction method.

14. A metal slurry for electrode formation according to claim 12, wherein said metal powder and said dispersion medium are present in a volume % content ratio between 1:

99 and 40;

60.

15. A metal slurry for electrode formation according to claim 12, wherein said metal powder comprises a silver powder.