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Chemical method for silver coating on copper powder surface

A technology of surface chemistry and copper powder, applied in coating and other directions, can solve the problems of no mention of powder conductivity, complex composition of silver ammonia solution, poisonous silver cyanide, etc., to achieve easy mass production and high oxidation resistance. , Eliminate the effect of silver plating

Inactive Publication Date: 2006-12-13
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Invention patent [CN1262043A] discloses a method of preparing silver-coated copper powder by substitution reaction, which is used for the preparation of antibacterial agents, without mentioning the conductive properties of the powder
[0004] The above-mentioned process of carrying out electroless silver plating on the surface of copper powder has the disadvantages of complex components of silver ammonia solution, poisonous silver cyanide, many times of plating, some need to carry out electroless plating at a temperature higher than room temperature, and the surface of copper powder needs Sensitization activation, etc., and during the plating process, the inner wall of the plating tank is easy to deposit silver layer, resulting in the waste of silver

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Get 10 grams of copper powder, add 5% dilute sulfuric acid to remove oxides on the surface of copper powder. Wash with distilled water 3 times, and filter off the water for later use. Take 3 grams of silver nitrate, add 200 milliliters of deionized water, add 19 milliliters of ammonia water, and stir to obtain a transparent solution. Add 1 g of sodium hydroxide, stir and add 5 ml of ammonia water to obtain a transparent silver amine solution. Add 15 grams of glucose, 24 milliliters of ethanol, 6 grams of polyethylene glycol, and 2 grams of sodium dodecylsulfonate into 200 milliliters of deionized water, and stir evenly to obtain a reducing solution. Then add the treated copper powder into the reducing solution, add the silver amine solution after stirring, and stir for 25 minutes. After filtration, wash with deionized water three times, filter, and vacuum dry at 40° C. to obtain silver-plated copper powder.

Embodiment 2

[0026] Get 50 grams of copper powder, add 5% dilute nitric acid to remove oxides on the surface of copper powder. Wash with distilled water 3 times, and filter off the water for later use. Take 12 grams of silver nitrate, add 1000 milliliters of deionized water, add 100 milliliters of ammonia water, and stir to obtain a transparent solution. Add 4 grams of sodium hydroxide, stir and add 25 milliliters of ammonia water to obtain a transparent silver amine solution. Add 50 grams of glucose, 110 milliliters of ethanol, 18 grams of polyethylene glycol, and 7 grams of sodium citrate into 1000 milliliters of deionized water, and stir evenly to obtain a reducing solution. Then add the treated copper powder into the reducing solution, add the silver amine solution after stirring, and stir for 35 minutes. After filtering, wash with deionized water three times, filter, and vacuum dry at 60° C. to obtain silver-plated copper powder.

Embodiment 3

[0028] Get 100 grams of copper powder, add 8% formic acid, remove copper powder surface oxide. Wash with distilled water 3 times, and filter off the water for later use. Take 42 grams of silver nitrate, add 2300 milliliters of deionized water, add 220 milliliters of ammonia water, stir to obtain a transparent solution. 10 g of sodium hydroxide was added, and after stirring, 70 ml of ammonia water was added to obtain a transparent silver amine solution. Add 140 grams of glucose, 180 milliliters of ethanol, 50 grams of polyethylene glycol, and 15 grams of sodium acetate into 2400 milliliters of deionized water, and stir evenly to obtain a reducing solution. Then add the treated copper powder into the reducing solution, add the silver amine solution after stirring, and stir for 45 minutes. After filtering, wash with ethanol three times, filter, and vacuum dry at 50° C. to obtain silver-plated copper powder.

[0029] Example 3:

[0030] Get 100 grams of copper powder, add 6% d...

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PUM

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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...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F1/02
Inventor 郭文利梁彤祥闫迎辉赵兴宇郝少昌唐春和
Owner TSINGHUA UNIV
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