Chemical method for silver coating on copper powder surface

Abstract

The invention relates to a method for copper powder surface chemical plating silver, belonging to field of chemical silver plating. Said method comprises following steps: putting copper powder into diluted acid of 5-10% to remove oxide on surface of copper powder; adding disperser of 1-30% of copper powder by weight, stabilizer of 10-60% of copper powder by weight into deionized water to form reducing liquid, adding copper powder and stirring; adding silver nitrate into deionized water, adding ammonia, stirring and adding sodium-hydroxide and getting silver amine solvent; adding silver amine solvent into reducing liquid under stirring, finishing chemical silver plating of copper surface 10-50 minutes later; filtering, separating and washing, vacuum drying and getting silver-coated copper powder. The process is characterized by simple preparation and raw material, reduced silver-plated layer on container wall by adding silver amine solvent into reducing liquid, high silver converting rate. The electrical resistance of got copper powder is smaller than 2*10-4 omegacm.

Description

technical field

[0001] The invention relates to a method for electroless silver plating on the surface of copper powder, belonging to the technical field of electroless silver plating. The obtained silver-plated copper powder has high oxidation resistance, electromigration resistance and low resistance value. The silver-plated copper powder is used as a conductive adhesive prepared as a conductive filler, and is used as a conductive connection material in the fields of electronic devices and integrated circuits. Background technique

[0002] Conductive adhesive has the advantages of lead-free pollution, low weight, and low curing temperature. As a conductive connection material, it is a substitute for tin-lead solder. Among various conductive adhesives, copper conductive adhesive is cheap and low in cost, but copper powder is particularly easy to oxidize during the production process, resulting in poor connection conductivity; nickel conductive adhesive has similar performa...