Metal microparticles provided with projections

Patent metadata

Field	Value
Publication number	US-9928932-B2
Application number	US-201214441483-A
Country	US
Kind code	B2
Filing date	Nov 8, 2012
Priority date	Nov 8, 2012
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

In response to the demand for shape-controlled metal microparticles accompanying rapid development and progress in industry in recent years, metal microparticles, which have projections on the surfaces of the particles that are integrated with the particles, are provided. The metal microparticles have integrated conical projections on the surfaces of the particles, and at least some of the projections are more than ¼ of the size of the particles. The protrusions that protrude from the metal microparticles melt and deform at a temperature lower than the melting point of the metal itself.

First claim

The invention claimed is:

1. A metal microparticle, which includes a nickel element contained therein and comprises a particle main body and a plurality of projections sticking out from the particle main body,
wherein a particle diameter of the particle main body is 5 μm or less,
wherein at least one projection of the plurality of projections tapers off to a point and has an apparent height by an electron microscope being in the range of more than ¼ to less than 8/4 relative to the particle diameter of the particle main body, and
wherein a ratio (d/D) of a crystallite diameter (d) to a particle diameter (D) of the particle main body is 0.02 or more.

2. The metal microparticle according to claim 1 , wherein the at least one projection has an apparent width thereof by an electron microscope that becomes gradually narrower from a base end to a front end thereof, and the apparent width of the base end is a value equal to or less than twice the apparent height.

3. The metal microparticle according to claim 1 , wherein a specific surface area of the metal microparticle is 2.5 times or more relative to a converted value of a specific surface area calculated from the particle diameter of the particle main body with an assumption that the metal microparticle is spherical.

4. The metal microparticle according to claim 1 , wherein the particle main body and the at least one projection are integrally formed from the same material.

5. The metal microparticle according to claim 1 , wherein a number of the plurality of projections are large projections with an apparent height by an electron microscope being larger than ¼ relative to the particle diameter of the particle main body, and the number of large projections is 30% or more relative to the total number of the projections.

6. A metal particle-containing composition, wherein the composition contains the metal microparticle according to claim 1 , and the said composition is in the form of a powder or a slurry.

7. The metal microparticle according to claim 2 , wherein a specific surface area of the metal microparticle is 2.5 times or more relative to a converted value of a specific surface area calculated from the particle diameter of the particle main body with an assumption that the metal microparticle is spherical.

8. The metal microparticle according to claim 2 , wherein the particle main body and the at least one projection are integrally formed from the same material.

9. The metal microparticle according to claim 3 , wherein the particle main body and the at least one projection are integrally formed from the same material.

10. The metal microparticle according to claim 5 , wherein the particle main body and the at least one projection are integrally formed from the same material.

11. The metal microparticle according to claim 1 , wherein a particle diameter of the particle main body is 1 μm or less.

12. The metal microparticle according to claim 1 , wherein the apparent height by the electron microscope is in the range of more than ½ to less than 5/4 relative to the particle diameter of the particle main body.

13. A method of producing the metal microparticle according to claim 1 , comprising the steps of:
introducing a nickel compound solution as a first fluid and a reducing agent solution as a second fluid into a processing device, the processing device comprising at least two processing surfaces facing each other, the at least two processing surfaces being operable to approach to and separate from each other, at least one of the at least two processing surfaces rotating relative to the other;
mixing the first and second fluids in a space formed between the at least two processing surfaces, thereby forming a thin film fluid between the at least two processing surfaces; and
separating nickel microparticle in the thin film fluid as the metal microparticle.

14. A method of producing a metal microparticle, comprising the steps of
introducing a nickel compound solution as a first fluid and a reducing agent solution as a second fluid into a processing device, the processing device comprising at least two processing surfaces facing each other, the at least two processing surfaces being operable to approach to and separate from each other, at least one of the at least two processing surfaces rotating relative to the other;
mixing the first and second fluids in a space formed between the at least two processing surfaces, thereby forming a thin film fluid between the at least two processing surfaces; and
separating nickel microparticle in the thin film fluid as the metal microparticle,
wherein the separated nickel microparticle includes a nickel element contained therein and comprises a particle main body and plural projections sticking out from the particle main body, and wherein at least one projection of the plural projections tapers to a point, and an apparent width of the at least one projection by an electron microscope becomes gradually narrower from a base end to a front end thereof, a longest apparent plain distance among the plural projections by the electron microscope is 7.5 μm or less, and an apparent height of the longest projection among the plural projections by the electron microscope is more than ⅙ relative to the longest apparent plain distance, the longest apparent plain distance being a longest distance between two front ends of two of the plural projections.

Assignees

• M Technique Co Ltd

Inventors

• Maekawa Masaki
• Enomura Masakazu

Classifications

• B22F1/065

  Spherical particles · CPC title

• B22F1/00

  Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties · CPC title

• B01J23/755

  Nickel · CPC title

• H01B1/02 Primary

  mainly consisting of metals or alloys · CPC title

• B22F9/24

  starting from liquid metal compounds, e.g. solutions · CPC title