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Title:
SILVER-PLATED FINE COPPER POWDER, CONDUCTIVE PASTE PRODUCED FROM SILVER-PLATED FINE COPPER POWDER, AND PROCESS FOR PRODUCING SILVER-PLATED FINE COPPER POWDER
Document Type and Number:
WIPO Patent Application WO/2008/059789
Kind Code:
A1
Abstract:
A process for producing a silver-plated fine copper powder characterized by treating a fine copper powder with an alkaline solution to remove organic substances present on the surface of the fine copper powder, washing the powder with water, washing an oxide present on the surface of the fine copper powder with an acidic solution, washing the powder with water, subsequently adding a reducing agent to an acidic solution containing this fine copper powder dispersed therein to produce a slurry of the fine copper powder, regulating the pH of the slurry, and then continuously adding to this fine-copper-powder slurry a solution of silver ions complexed with a chelating agent to thereby form a silver layer on the surface of the fine copper powder by electroless displacement plating and reductive plating. This process eliminates problems in conventional silver-plated fine copper powders, e.g., that the fine copper powders obtained through silver plating reaction differ in color tone according to the oxidized state thereof before silver plating and that the silver plating causes a decrease in tap density. The silver-plated fine copper powder is excellent in electrical conductivity and reproducibility in silver plating reaction and has almost the same tap density as the raw fine copper powder.

Inventors:
HAGA, Takahiro (Ltd. Shirogane Plant 3-3-1 Shirogane-cho, Hitachi-cit, Ibaraki 56, 3170056, JP)
Application Number:
JP2007/071907
Publication Date:
May 22, 2008
Filing Date:
November 12, 2007
Export Citation:
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Assignee:
Nippon Mining & Metals Co., Ltd. (10-1, Toranomon 2-chome Minato-k, Tokyo 01, 1050001, JP)
日鉱金属株式会社 (〒01 東京都港区虎ノ門二丁目10番1号 Tokyo, 1050001, JP)
International Classes:
B22F1/02; B22F1/00; C23C18/44; H01B1/22; H01B5/00
Foreign References:
JP2002245849A2002-08-30
JP2003147316A2003-05-21
JP2006161081A2006-06-22
JP2005044798A2005-02-17
JPH06240463A1994-08-30
JPH10212501A1998-08-11
JP2000248303A2000-09-12
JP2004052044A2004-02-19
Attorney, Agent or Firm:
OGOSHI, Isamu (OGOSHI International Patent Office, Daini-Toranomon Denki Bldg. 5F,3-1-10 Toranomon, Minato-ku, Tokyo 01, 1050001, JP)
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