Process for forming novel silver powder composition

• US 4,463,030 A
• Filed: 12/24/1980
• Issued: 07/31/1984
• Est. Priority Date: 07/30/1979
• Status: Expired due to Fees

• Current Assignee: Vistatech Corporation
• Original Assignee: Graham Magnetics, Inc.
• Inventors: Deffeyes, Robert J., Armstrong, Harris W.
• Primary Examiner(s): Lusignan, Michael R.
• Application Number:
  US06/485,431
• Time in Patent Office: 1,315 Days
• Field of Search: 106/1.14, 106/1.19, 252/514, 427/216
• US Class Current: 427/216
• CPC Class Codes: B22F 3/1003 Use of special medium during sintering, e.g. sintering aid
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01P 2004/01 depicted by an image
• CPC Class Codes: C01P 2004/02 obtained by optical microscopy
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2004/62 Submicrometer sized, i.e. from 0.1-1 micrometer
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C01P 2004/80 Particles consisting of a mixture of two or more inorganic phases
• CPC Class Codes: C01P 2006/37 Stability against thermal decomposition
• CPC Class Codes: C09C 1/62 Metallic pigments or fillers C09C1/0015 takes precedence
• CPC Class Codes: C09D 5/10 containing metal dust
• CPC Class Codes: C22C 1/0466 Alloys based on noble metals
• CPC Class Codes: C22C 32/0094 with organic materials as the main non-metallic constituent, e.g. resin
• CPC Class Codes: H01B 1/16 the conductive material comprising metals or alloys
• 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 2203/1105 Heating or thermal processing not related to soldering, firing, curing or laminating, e.g. for shaping the substrate or during finish plating
• CPC Class Codes: H05K 2203/121 Metallo-organic compounds
• CPC Class Codes: H05K 3/105 by conversion of non-conductive material on or in the support into conductive material, e.g. by using an energy beam

Abstract

A novel silver powder paint composition characterized by a very low fusion, or film-forming temperature, probably assignable to the relatively small amount of oxides or other undesirable occulsions within coatings formed of the powder. The invention also relates to a new process for forming such a powder; the process is believed to involve the formation of a fatty-acid silver reaction product of the surface on the silver powder before it is subjected to fusion into a metallic coating. During fusion the decomposing reactant seems to act as a flux aiding the formation of a metal film of superior appearance and strength.

Claims

1. A process for making a metal powder product comprising the steps of:

(a) mixing an organometallic salt of a metal and a carboxylic acid in a liquid organic reactant; and

, simultaneously

(b) decomposing said salt to form a metal powder in the presence of said reactant; and

(c) forming a protective barrier about newly formed particles of said metal powder by reacting said organic reactant with newly formed particles of said metal powder.

2. A process as defined in claim 1 wherein said organic reactant is a carboxylic acid having a chain of at least 8 carbon atoms.

3. A process as defined in claim 1 wherein said metal is silver.

4. A process as defined in claim 2 wherein said organometallic salt is an oxalate.

5. A process as defined in claim 1 wherein some copper is incorporated into said oxalate with said silver.

6. A process as defined in claim 2 wherein said metal is silver.

7. A process as defined in claim 4 wherein said metal is silver.

8. A process as defined in claim 2 wherein said carboxylic acid reacted to form a protective barrier about newly formed particles of silver powder, is oxalic acid.

9. A process as defined in claim 6 wherein said carboxylic acid, reacted to form a protective barrier about newly formed particles of silver powder, is palmitic acid.

10. A process as defined in claim 8 wherein said powder is fusible into a metallic silver film at 250°

C.

11. A process as defined in claim 6 wherein said organic reactant forming said reactive barrier is coated upon said silver powder in a quantity effective to make said powder non-conductive and fusible to a conductive powder at about 250°

C.