Preparation method of deposited, ventilated and reduced nanometer-level silver powder

Abstract

The invention provides a chemical preparation technology of deposited, ventilated and reduced nanometer-level silver powder, comprising the following steps of: fast reacting Ag<1+>ions with OH<1-> ions to generate greatly fine AgOH particles under the activation of a microwave field by adopting a microwave activation-water solution deposition-H2 reduction process; adding low-cost release agent and a low-cost dispersing agent to a reaction solution; separating a waste solution and a cleaning solution which are contained in a mother solution from deposits by adopting a continuous type fast centrifugal separation method, and drying in vacuum at lower temperature so as to obtain nanometer-level superfine AgOH powder; and then reducing at lower temperature in a ventilating type H2 reduction furnace so at to obtain the nanometer-level (average grain diameter is less than and equal to 40 nanometers) silver powder. The invention has the advantages of low cost, simple process, small investment and high production efficiency, and is suitable for the large-scale industrialized production of the nanometer-level superfine silver powder; and in addition, the chemical preparation technology is more suitable for the investment of small and medium enterprises and has wide market prospect of products.

Description

technical field [0001] The invention belongs to the technical field of metal powder preparation in metal materials, and in particular provides an industrial preparation technology for preparing nano-scale silver powder through a new precipitation-breathing reduction process, which is suitable for industrial scale production of nano-scale silver powder. Background technique [0002] Nano-scale silver powder is widely used in the electronics industry, especially in recent years, with the rapid development of microelectronics technology in the information industry, the demand for nano-scale silver paste coatings has increased rapidly. The annual demand in the United States is about 1,000 tons, and the annual demand in Japan and Europe is about 2,500 tons. my country's annual demand in the past five years is 300 tons, and Taiwan's is about 200 tons. World demand is growing at a rate of 20-28% every year. In addition, nano-scale silver powder is also used in tungsten-silver ult...

AI Technical Summary

Problems solved by technology

But at present, there are still unresolved problems in the technology of preparing silver powder by reduction of aqueous solution. One is that the reaction and precipitation time is long, generally 1 to 2 hours, sometimes up to 4 hours. Aggregation grows into micron-scale particles, which is very unfavorable for the preparation of nano-scale silver powder

Third, the separation of mother liquor and silver particles and repeated cleaning and filtration are very difficult

What follows is that the amount of liquid treatment is too large, the production efficiency is very low, the actual amount of silver powder is very small, and the actual yield is low.

When preparing nano-scale silver powder, in order to control the growth of silver particles, a silver ion solution with low molar concentration is often used, which will further cause a larger amount of mother liquor, a further reduction in the actual yield, and a significant decline in production efficiency. Therefore, use The technology of preparing nano-silver powder by solution reduction method cannot be put into industrial production on a large scale in any country in the world.

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