Method for preparing silver-coated copper powder through radiation reduction

Abstract

The invention provides a method for preparing silver-coated copper powder through radiation reduction, comprising the following steps of (1) preparing the copper powder: adding ammonia water into copper sulphate solution, dripping a reducing agent solution into the copper sulphate solution, reacting at 70-80 DEG C, and washing obtained copper powder by using dilute sulphuric acid and deionized water so as to obtain clean copper powder; (2) preparing the silver-coated copper powder through the radiation reduction: adding the clean copper powder into the deionized water which contains a dispersing agent, after adding silver ammonia solution and an active particle catcher and feeding an inert gas, placing the mixture in a radiation source to perform a radiation reduction reaction in a stirring state, wherein the irradiation dose rate is 0.8-6.0 kGy / h, and the absorbed dose is 10-30 kGy; and finally washing a reaction product by using the deionized water to obtain the silver-coated copper powder with a grain size of 0.5 mum-6.5 mum. The plating layer of the silver-coated copper powder prepared by the method is compact without hole corrosion, the conductive performance is good, the process is simple, the production cost is low, and the method is in favour of the development of electronic industry.

Description

technical field [0001] The invention relates to the technical field of using nuclear radiation technology to prepare metal powder materials, in particular to a preparation method for preparing silver-plated copper powder through radiation reduction. Background technique [0002] With the rapid development of the electronics industry, there is an increasing demand for electronic pastes with silver powder as the main functional phase. However, the silver-based paste is not only expensive, but also the electromigration of silver ions under hot and humid conditions will lead to an increase in coating resistance and a decrease in conductivity; therefore, in order to reduce costs and maintain good conductivity of silver powder, people In the study, silver-plated copper powder is used as a substitute for silver powder. Chinese patent literature (publication number CN 1425738) discloses "a method for multiple silver plating using stannous chloride as a sensitizer" to prepare silver...

AI Technical Summary

Problems solved by technology

However, the silver-based paste is not only expensive, but also the electromigration of silver ions under hot and humid conditions will lead to an increase in coating resistance and a decrease in conductivity; therefore, in order to reduce costs and maintain good conductivity of silver powder, people In the study of using silver-plated copper powder as a substitute for silver powder

Chinese patent document (publication number CN 1425738) discloses " a kind of method utilizing tin protochloride to be sensitizer repeated silver plating " to prepare silver-coated copper powder, and this method needs repeated silver plating when preparing silver-plated copper powder, The efficiency of silver plating is reduced, and the silver-plated copper powder prepared by this method needs to undergo high-temperature heat treatment to make the surface smooth and dense, which increases the possibility of silver powder bonding during heat treatment

However, this process requires a large amount of organic reagents to clean the surface of the powder, so its industrial application is difficult

Chinese patent literature (publication number CN 101244459A) discloses a method for improving the catalytic activity of copper powder surface by using the modification of rare earth metals; Chinese patent literature (publication number CN 1403233A) discloses a copper powder treated with Powder, adding the silver plating method in the silver nitrate solution complexed by organic amine compounds, can obtain silver-plated copper powder with high conductivity; Chinese patent literature (publication number CN 101294281A) discloses a complex The method of silver-plating in the combined acidic silver-containing solution can obtain silver-plated copper powder for low-temperature slurry; Chinese patent document (publication number CN 101032750A) discloses a , Potassium thiocyanate, etc. as a complexing agent to prepare flake silver-plated copper powder, the process is complicated, and potassium thiocyanate, one of its complexing agents, is a toxic substance

Due to the occurrence of replacement reaction, copper ions need to diffuse into the solution from the surface of copper powder through the silver-plated layer, so that the silver layer in the prepared silver-plated copper powder is loose and has holes, and it is easy to oxidize at high temperature. Its comprehensive performance is comparable to that of pure silver powder. There is a big gap