Preparation method of high dispersibility superfine silver powder with adjustable grain diameter

A high-dispersion, ultra-fine silver technology, applied in the field of liquid-phase preparation of ultra-fine silver powder, can solve the problems of difficulty in controlling powder dispersion, unfavorable for large-scale industrial production, low output per unit volume, etc., and achieve densification and shrinkage. The effect of low rate, excellent end product performance and narrow particle size distribution

Active Publication Date: 2013-05-01
GUANGDONG FENGHUA ADVANCED TECH HLDG
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The technical point of preparing silver powder by liquid phase reduction method is to control the dispersion, size and uniformity of the reduced silver particles, because the ultrafine powder is easy to agglomerate in the aqueous solution, resulting in poor dispersion, which is difficult to meet the requirements of ordinary electronic paste, especially It is the printing and sintering demand of high-end silver paste. For example, the patent with application number 200510128715.6 requires subsequent heat treatment, and the concentration of reactants is low, and the output per unit volume is low, which is not conducive to mass industrial production. Although the patent with application number 200710049490.4 is silver nitrate The concentration is high, but it does not involve the selection of surfactants, and the dispersibility of the powder obtained by reduction is difficult to control

Method used

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  • Preparation method of high dispersibility superfine silver powder with adjustable grain diameter
  • Preparation method of high dispersibility superfine silver powder with adjustable grain diameter
  • Preparation method of high dispersibility superfine silver powder with adjustable grain diameter

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preparation example Construction

[0014] First, the basic scheme of the preparation method of the present invention is briefly described: a preparation method of highly dispersed ultrafine silver powder with adjustable particle size, the steps are: 1. Dissolving silver nitrate and surfactant in water is configured into silver solution A; ②. Dissolve ascorbic acid, pH regulator and surfactant in water to prepare reducing solution B; ③. Prepare alkaline pH regulator in alkaline aqueous solution C; ④. Add liquid C and Liquid A, make the silver powder grow evenly;

[0015] Or: ①, dissolving silver nitrate and surfactant in water to configure silver solution A; ②, dissolving ascorbic acid and surfactant in water to configure reducing solution B1; ③, configuring alkaline pH regulator in alkaline aqueous solution C ; ④, configure the pH regulator into an aqueous solution with a certain pH value as the reaction bottom liquid D; ⑤, add liquid A, liquid B1 and liquid C to liquid D dropwise within the specified time, so ...

Embodiment 1

[0017] 157gAgNO 3 Dissolve 1 g of gum in 1 L of deionized water (hereinafter referred to as water), stir and dissolve to obtain a silver solution. Add 120 g of ascorbic acid and 2 g of gum into 1 L of water, add a pH regulator to adjust the pH to 3, and obtain a reducing solution. Control the reaction temperature at (30-35) ° C, drop the silver-containing solution into the reducing solution within 30 minutes, and add sodium hydroxide solution dropwise at the same time to control the reaction pH value to 3±0.5, stir for 15 minutes after the addition, and let stand Precipitate, wash the powder with water until the conductivity of the filtrate is less than 100μs / cm, filter and dry at 60°C, and sieve to obtain silver powder. Powder test results: see the attached SEM picture of the powder figure 1 , average particle size 4.0μm; tap density 5.1g / ml; particle size distribution S.D. / D50 is 0.425.

Embodiment 2

[0019] The amount of material used in Example 1 is enlarged by 200 times, and other processes are consistent with Example 1. Powder testing results: the average particle size of the powder is 3.8 μm; the tap density is 4.9 g / ml; the particle size distribution S.D. / D50 is 0.451.

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Abstract

The invention relates to a preparation method of high dispersibility superfine silver powder with adjustable grain diameter, comprising the following steps: 1. dissolving silver nitrate and surfactant in water to prepare silver solution A; 2. dissolving ascorbic acid, PH regulator and surfactant in water to prepare reducing liquid B; 3. preparing alkaline aqueous solution C by alkaline PH regulator; dropwise adding alkaline aqueous solution C and silver solution A to reducing liquid B at the set time. PH value of the reducing liquid B and flow velocity of alkaline aqueous solution C are adjusted, so that silver power particle size can be easily adjusted and the silver power particles can grow up uniformly. The silver powder obtained by the method of the invention has the characteristics of polyhedral microcosmic appearance, good dispersibility, narrow size distribution, high tap density and good sintering character.

Description

technical field [0001] The invention relates to a liquid-phase preparation method of ultrafine silver powder, in particular to a preparation method of highly dispersed ultrafine silver powder with adjustable particle size used in electronic paste. Background technique [0002] Silver powder is the most widely used and the largest amount of precious metal powder in the electronics industry. Its morphology, particle size, uniformity, and dispersion are key factors affecting the film-forming performance of silver paste. Therefore, it can be used to make various low-temperature Curing polymer silver paste, conductive adhesive, or sintered silver paste including electrode paste for various ceramic components. [0003] The most commonly used method for preparing silver powder in large quantities at present belongs to the liquid phase reduction method. The production process and equipment of the liquid phase reduction method are simple, the production cost is low, and the product p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F9/24
Inventor 孟淑媛唐元勋吴海斌彭建雄孔祥冬陆进辉黄相文
Owner GUANGDONG FENGHUA ADVANCED TECH HLDG
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