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Method for preparing silver micro-powder for high-temperature sintering silver pastes

A technology of high-temperature sintering and silver micropowder, which is applied in the field of preparation of functional silver micropowder, can solve problems such as difficult mass production, difficulty in solid-liquid separation and collection, high energy consumption of high-speed centrifugal separation, etc., and achieves stable industrial production and easy collection and washing , Improve the effect of uniformity

Active Publication Date: 2012-10-17
广东羚光新材料股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method is not conducive to the control of the particle size of silver powder, and high-speed centrifugation consumes a lot of energy, requires high equipment, solid-liquid separation and collection is difficult, and is difficult to meet industrialized mass production; the preparation method of the publication number CN1785558 adopts silver nitrate solution in the oxidation-reduction process. Add it dropwise to the reducing agent and dispersant, and adjust the pH value of the solution with ammonia water to prepare micron-sized silver powder, and obtain micron-sized spherical silver powder with different particle sizes of 0.1-3.0 μm
This method strengthens the stable control of the pH value in the reaction process, so that the whole preparation process is in a relatively stable and controllable range, which is conducive to scale-up production, but with the increase of batch production, this method has local reaction concentration and overall reaction. The concentration difference will continue to widen. Since the reaction nucleation process is a fast and instantaneous reaction (millisecond level), the concentration difference generated by the enlarged production will directly affect the uniformity of the silver powder.

Method used

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  • Method for preparing silver micro-powder for high-temperature sintering silver pastes
  • Method for preparing silver micro-powder for high-temperature sintering silver pastes
  • Method for preparing silver micro-powder for high-temperature sintering silver pastes

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preparation example Construction

[0029] The invention is a method for preparing silver micropowder for high-temperature sintered silver paste, comprising the following steps:

[0030] (1) Prepare silver ammonia solution, add polymer thickener solution, fully stir and dissolve to form a sol-like silver liquid system. Wherein, the polymer thickener solution is selected from one or a mixed solution of gum arabic, gelatin, polyanion cellulose, methyl cellulose, sodium carboxymethyl cellulose.

[0031] (2) Prepare a reducing system composed of reducing agent, sodium hydroxide and polymer thickener solution, and fully stir to form a sol-like reducing system. In the system, one or more of vitamin C, formaldehyde, hydrazine hydrate, formic acid and sodium borohydride can be selected as the reducing agent, and the mass ratio of reducing agent to silver is 1:1-20; the mass ratio of silver ion to sodium hydroxide It is 4~6:1. Optimally, the mass ratio of reducing agent to silver is 1:1.2-15; the mass ratio of silver i...

Embodiment 1

[0038] (1) Weigh 50 g of polyanionic cellulose and dissolve it in 1000 ml of deionized water, stir well to dissolve into sol A with a mass ratio of 5%.

[0039] (2) Weigh 40g of analytically pure AgNO 3 Dissolve it in 200ml of deionized water to make a silver nitrate solution; add 30-40ml of 25-28% ammonia water to the silver nitrate solution until the solution turns from turbid to clear to obtain a silver ammonia solution. Then add 20ml of formulated sol A, add deionized water to dilute to 400ml, stir and mix well to obtain a silver sol system.

[0040](3) Weigh 5g of analytically pure NaOH and dissolve it in 200ml of deionized water. After stirring to dissolve fully, add 5ml of 80% analytically pure hydrazine hydrate and 20ml of formulated sol A, and finally add deionized water to dilute to 400ml. Thoroughly stir and mix uniformly to obtain a reduced sol system.

[0041] (4) Weigh 1.5g of polyvinylpyrrolidone PVP, heat and dissolve it in 200ml of deionized water to prepare...

Embodiment 2

[0046] (1) Weigh 50 g of polyanionic cellulose and dissolve it in 1000 ml of deionized water, stir well to dissolve into sol A with a mass ratio of 5%.

[0047] (2) Weigh 40g of analytically pure AgNO 3 Dissolve it in 200ml of deionized water to make a silver nitrate solution; add 30-40ml of 25-28% ammonia water to the silver nitrate solution until the solution turns from turbid to clear to obtain a silver ammonia solution. Then add 10ml of formulated sol A, add deionized water to dilute to 400ml, stir and mix well to obtain a silver sol system.

[0048] (3) Weigh 5g of analytically pure NaOH and dissolve it in 200ml of deionized water. After stirring to dissolve fully, add 5g of analytically pure formaldehyde and 10ml of formulated sol A, and finally add deionized water to dilute to 400ml, stir and mix evenly to obtain Reduce the sol system.

[0049] (4) Weigh 1.5g of polyvinylpyrrolidone PVP, heat and dissolve it in 200ml of deionized water to prepare a protective solution...

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Abstract

The invention discloses a method for preparing silver micro-powder for high-temperature sintering silver pastes, which comprises the following steps: preparing a colloidal liquid silver system, a colloidal reduction system and protection solution firstly; then mixing the three. In the invention, a sol gel process and a solution chemical reduction method are used to effectively control the reaction process, so that the industrialized production can be performed stably, and the uniform reaction under the condition of production enlarging still can be ensured, thereby greatly improving the uniformities of shapes and other superficial characteristics of silver particles generated by reaction, and eventually generating flocculating soft silver powder wodges which are easy to carry out post-processing such as collecting and washing, and the like.

Description

technical field [0001] The invention relates to the preparation of functional silver micropowder, and the preparation method is suitable for industrial large-scale production of silver micropowder. The prepared silver micropowder can be matched and used in proportion to satisfy the preparation of electronic paste. Background technique [0002] Metal ultrafine powder itself has superior catalytic properties, magnetic properties, electrical properties, etc., so it has more and more applications in aerospace, atomic energy, electronics, powder metallurgy, chemical and other industries, as well as medicine and bioengineering. [0003] Among them, silver micropowder is widely used in the fields of electronics and electronic materials due to its excellent conductivity and application performance, and has an irreplaceable position in the electronics industry. Silver micropowder is mainly used in the preparation of conductive silver paste. The electronic silver paste series product...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F9/24
Inventor 李跃文梁炳联娄红涛王惠敏黎万全宋先刚陈平基彭梅志邱衍嵩
Owner 广东羚光新材料股份有限公司
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