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Preparation method for silver powder

A kind of silver powder, contact preparation technology

Active Publication Date: 2012-07-04
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to solve the problem that in the existing method, the reaction of the reducing agent used is unstable or easily leads to the agglomeration of silver powder; and by adding a large amount of dispersant to control the particle size to alleviate the agglomeration, the existing difficulties in subsequent separation and washing, etc., to provide a A new method of preparing silver powder

Method used

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preparation example Construction

[0039] The preparation method of silver powder of the present invention is based on 100 parts of the quality of silver nitrate, specifically can comprise the following steps:

[0040] a. Preparation of silver nitrate solution:

[0041] Silver nitrate 100

[0042]Deionized water 600-1000

[0043] Dispersant 1.0-10

[0044] Thickener 0.5-6

[0045] The above-mentioned substances are mixed and stirred until completely dissolved according to their corresponding parts by weight;

[0046] b. Preparation of reducing agent solution:

[0047] Deionized water 100-300

[0048] Dispersant 1.0-10

[0049] Thickener 0.5-6

[0050] Neutralizer 10-80

[0051] Strong reducing agent 0.1-5

[0052] Medium strong reducing agent or medium reducing agent 1-95

[0053] Weak reducing agent 5-200

[0054] Prepare reducing agent solution by above-mentioned each material and corresponding weight portion thereof;

[0055] c. Preparation of silver powder:

[0056] Heat 1000 parts by mass of t...

Embodiment 1

[0059] a. Preparation of silver nitrate solution

[0060] 60g of silver nitrate, 1000g of deionized water, 2.5g of polyvinylpyrrolidone, and 2g of hydroxymethylcellulose were mixed and stirred until completely dissolved.

[0061] b. Preparation of reducing agent solution

[0062] Mix and stir 0.06 g of hydrazine hydrate (88%) solution, 200 g of deionized water, 13.5 g of ascorbic acid, 20 g of glucose, 0.5 g of polyvinylpyrrolidone, 2 g of hydroxymethyl cellulose, and 24 g of 25% concentrated ammonia water until completely dissolved.

[0063] c. Preparation of silver powder

[0064] Heat the silver nitrate solution prepared in a to a constant temperature of 72°C in a water bath, and stir at a speed of 500r / min, then drop the reducing agent solution prepared in b into the silver nitrate solution at a speed of 5ml / min, Continue to stir for 5 minutes after dripping, take it out, let it stand, cool, precipitate, and age. Pour off the supernatant liquid, wash the silver powder t...

Embodiment 2

[0067] a. Preparation of silver nitrate solution

[0068] Silver nitrate 60g, deionized water 1000g, polyethylene glycol 400 (PEG) 5g, carboxymethyl starch sodium 3g, mix and stir until completely dissolved.

[0069] b. Preparation of reducing agent solution

[0070] Hydrazine hydrate (88%) solution 0.06g, deionized water 200g, formaldehyde (37%) 0.36g, polyethylene glycol 400 (PEG) 1.25g, sodium carboxymethyl starch 3g, glucose 20g, ammonium bicarbonate ( AR) 26.7g, mixed and stirred until completely dissolved.

[0071] c. Preparation of silver powder

[0072] Heat the silver nitrate solution prepared in a to a constant temperature of 70°C in a water bath, and stir at a speed of 300r / min, then drop the reducing agent solution prepared in b into the silver nitrate solution at a speed of 4ml / min, Continue to stir for 5 minutes after dripping, take it out, let it stand, cool, precipitate, and age. Pour off the supernatant liquid, wash the silver powder twice with alcohol and...

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Abstract

The invention provides a preparation method for silver powder, which comprises a step of contacting a silver nitrate solution with a reducing agent solution, thereby preparing the silver powder, wherein the silver nitrate solution contains a dispersing agent; the reducing agent solution contains a dispersing agent and a neutralizing agent; the silver nitrate solution and / or the reducing agent solution contain / contains a thickening agent; and a reducing agent in the reducing agent solution contains a strong reducing agent and a weak reducing agent and contains a medium strong reducing agent or medium reducing agent at the same time. According to the preparation method provided by the invention, the thickening agent is used for adjusting a viscosity of a reaction system, thus the aggregation of the silver powder is efficiently prevented; the method of using different reducing agents together is adopted for realizing the stability of the acidic and basic properties and the reaction rate of the reaction system, thereby preparing the silver powder with basically consistent appearance and excellent dispersing property; and the grain size adjustment and the appearance adjustment for the silver power can be realized by selecting different reducing agents in proportions, and the stability of the reaction rate also can be controlled.

Description

technical field [0001] The invention relates to a method for preparing silver powder, which belongs to the field of preparation of rare metal powder. Background technique [0002] Silver powder is the most widely used and most used precious metal powder in the electronics industry. It is the basic and key functional material for the production of various electronic components, and the preparation of silver powder is a key step in its wide application. [0003] The main silver powder preparation methods at home and abroad mainly include: thermal decomposition method, electrochemical method, physical method and chemical reduction precipitation method. Among them, the chemical reduction precipitation method is the most important silver powder preparation method because of its simple process and low production cost. [0004] There are three major difficulties in the preparation of silver powder by the current chemical reduction precipitation method: first, the control of the par...

Claims

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Application Information

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IPC IPC(8): B22F9/24
Inventor 廖炜谭伟华周勇姜占锋
Owner BYD CO LTD
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