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Method for preparing spherical superfine silver powder by using chemical reduction method

A technology of ultrafine silver and reduction method, which is applied in the field of preparing spherical ultrafine silver powder by chemical reduction method, can solve the problems of difficulty in washing, loss of silver powder, low yield, etc., and achieves the effects of low price, less aggregation and good dispersibility.

Inactive Publication Date: 2010-06-02
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Viscous oleic acid is often used as a dispersant, resulting in difficulty in washing and loss of silver powder, resulting in low yield

Method used

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  • Method for preparing spherical superfine silver powder by using chemical reduction method
  • Method for preparing spherical superfine silver powder by using chemical reduction method
  • Method for preparing spherical superfine silver powder by using chemical reduction method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Prepare 100ml of silver nitrate solution with a substance concentration of 0.5mol / L and 100ml of an ascorbic acid solution with a substance concentration of 0.25mol / L with deionized water, wherein the ratio of silver nitrate to ascorbic acid is 2:1, and then take silver nitrate 1.5% by mass, that is, 0.127g of gelatin was swelled in hot deionized water with a volume of 20ml at 60°C for half an hour. At room temperature, with the speed of the magnetic stirrer adjusted to 600r / min, the silver nitrate solution was added dropwise to the ascorbic acid solution, gelatin was added dropwise after precipitation occurred, and the pH of the reaction solution was adjusted to 7±0.2 with ammonia water. After the titration, stir for 60 minutes, filter and wash, first wash three times with deionized water, then change to absolute ethanol for three times, dry the washings in a 50°C drying oven, put them in a muffle furnace, and raise the temperature to 350°C at 5°C / min Heat treatment at...

Embodiment 2

[0027] Prepare 100ml of silver nitrate mass concentration with deionized water respectively as a solution of 0.25mol / L and 50ml of ascorbic acid mass concentration as a solution of 0.25mol / L, wherein the ratio of silver nitrate to ascorbic acid mass is 2: 1, then take The gelatin with 1.5% silver nitrate mass, that is 0.0637g, was swelled in hot deionized water with a volume of 20ml at 40°C for half an hour. Under the condition of stirring speed of 400r / min at room temperature, silver nitrate solution was added dropwise to ascorbic acid solution, gelatin was added dropwise after precipitation occurred, and the pH of the reaction solution was adjusted to 7±0.2 with ammonia water. After the titration, stir for 30 minutes, filter and wash, first wash with deionized water three times, then change to absolute ethanol for three times, and dry the washings in a 50°C drying oven, then put them in a muffle furnace, and heat up to 350°C at 5°C / min. Heat treatment at ℃ for one hour to re...

Embodiment 3

[0030] The mass ratio of silver nitrate and ascorbic acid is 2:1, the mass concentration of silver nitrate is 0.5mol / L, and the volume is 100ml, the mass concentration of ascorbic acid is 0.5mol / L, and the volume is 50ml. The dosage of gelatin is 1% by mass of silver nitrate, that is, 0.085g, which is swelled in 20ml of hot deionized water at 50°C for half an hour. Stir at room temperature at a speed of 200r / min, add the silver nitrate solution to the ascorbic acid solution drop by drop, add gelatin drop by drop after precipitation occurs, and adjust the pH of the reaction solution to 6±0.2 with ammonia water. After the titration, stir for 40 minutes to filter and wash. First, wash with deionized water three times and then change to absolute ethanol for three times. The washings are dried in a 50°C drying oven and then put into a muffle furnace. The temperature is raised to 350°C at 5°C / min ℃, heat treatment for one hour to remove impurities.

[0031] The particle size and sc...

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Abstract

The invention provides a method for preparing spherical superfine silver powder by using a chemical reduction method, using ascorbic acid to reduce silver nitrate and using gelatin as a dispersing agent. An ascorbic acid solution and a silver nitrate solution with certain concentrations are respectively prepared with the mole ratio of the amounts of the silver nitrate to the ascorbic acid of 2:1; the silver nitrate is dropwise added in the ascorbic acid solution while stirring, the gelatin is dropwise added when sediments start to generate, and the pH value of a reaction solution is regulated by ammonia water; the reaction solution is filtered and washed after titration, the sediments are taken out, dried in a drying oven and then is put in a muffle furnace to be heated to 350 DEC C, and then impurities are removed through heat preservation and thermal treatment. The prepared silver powder is in a spherical shape or a shape similar to a ball and has the advantages of smooth surface, less agglomeration and favorable dispersion; the impurity content is less than 5*10-4, the specific surface area is from 0.8 to 1.5 m2.g-1, the thermal gravitation is less than 2%, the tap density is about 4g.cm-3, and the particle size distribution is from 0.5 to 3 mum. The method can be used for producing electrode slurry for sheet-type elements, silver paste for the glass of saloon cars, and the like, and has important industrial application value.

Description

technical field [0001] The invention relates to a method for preparing spherical ultrafine silver powder by a chemical reduction method, which belongs to the field of preparation of rare metal ultrafine powder. Background technique [0002] The rapid development of the electronic information industry has driven the development of the electronic paste and ultra-fine silver powder industries. Metal silver has an irreplaceable position in the electronics industry because of its high electrical conductivity and excellent application performance. Therefore, silver powder is the most widely used and the largest amount of precious metal powder in the electronics industry, and it is the basic and key functional material for the production of various electronic components. The spherical ultrafine silver powder with a particle size distribution of several microns is widely used in the production of electrode paste for chip components and silver paste for car glass. Conductive silver...

Claims

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Application Information

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IPC IPC(8): B22F9/24
Inventor 甘国友严继康陈忠文刘杰孙加林
Owner KUNMING UNIV OF SCI & TECH
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