Copper powder and method for producing same

Patent metadata

Field	Value
Publication number	US-12049684-B2
Application number	US-202318196614-A
Country	US
Kind code	B2
Filing date	May 12, 2023
Priority date	Dec 28, 2016
Publication date	Jul 30, 2024
Grant date	Jul 30, 2024

Abstract

There are provided an inexpensive copper powder, which has a low content of oxygen even it has a small particle diameter and which has a high shrinkage starting temperature when it is heated, and a method for producing the same. While a molten metal of copper heated to a temperature, which is higher than the melting point of copper by 250 to 700° C. (preferably 350 to 650° C. and more preferably 450 to 600° C.), is allowed to drop, a high-pressure water is sprayed onto the heated molten metal of copper in a non-oxidizing atmosphere (such as an atmosphere of nitrogen, argon, hydrogen or carbon monoxide) to rapidly cool and solidify the heated molten metal of copper to produce a copper powder which has an average particle diameter of 1 to 10 μm and a crystallite diameter Dx (200) of not less than 40 nm on (200) plane thereof, the content of oxygen in the copper powder being 0.7% by weight or less.

First claim

The invention claimed is:

1. A copper powder which has an average particle diameter of 1 to 10 lam and a crystallite diameter Dx (200) of not less than 40 nm on (200) plane thereof, the copper powder consisting of 0.2% by weight or less of oxygen and the balance being copper and unavoidable impurities, the copper powder having a temperature of not lower than 580° C. at a shrinkage percentage of 1.0% in a thermomechanical analysis thereof.

2. A copper powder as set forth in claim 1 , which has a circularity coefficient of 0.80 to 0.94.

3. A copper powder as set forth in claim 1 , wherein a ratio of the content of oxygen to a BET specific surface area of the copper powder is 0.8 wt %·g/m 2 or less.

4. A copper powder as set forth in claim 1 , which has a crystallite diameter Dx (111) of not less than 130 nm on (111) plane thereof.

5. A copper powder as set forth in claim 1 , wherein the content of oxygen in the copper powder is 0.15% by weight or less.

6. A conductive paste wherein a copper powder as set forth in claim 1 is dispersed in an organic component.

7. A conductive paste as set forth in claim 1 , which is a baked type conductive paste.

Assignees

• Dowa Electronics Materials Co Ltd

Inventors

• Yoshida Masahiro
• Inoue Kenichi
• Ebara Atsushi
• Michiaki Yoshiyuki
• Yamada Takahiro

Classifications

• B22F9/082 Primary

  atomising using a fluid (using centrifugal force B22F9/10) · CPC title

• B22F1/09

  Mixtures of metallic powders · CPC title

• B22F1/05

  Metallic powder characterised by the size or surface area of the particles · CPC title

• H01B1/22

  the conductive material comprising metals or alloys · CPC title

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title