Method for preparing submicron silver powder for electro-conductive paste

A submicron-level, conductive paste technology, applied in the field of conductive paste, can solve the problems of insufficient conductivity of conductive paste, wide distribution range of silver powder particle size, uneven particle size, etc., and achieve low equipment requirements, The effect of narrow distribution range and uniform particle size

Inactive Publication Date: 2012-11-07
SHENZHEN SENLONT ELECTRONICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although this method has the advantages of simple process, easy operation, and low energy consumption, it has the disadvantages of wide particle size distribution range, inconsistent shape, uneven particle size, and large particle size of the silver powder. The conductivity and other properties of the slurry are not good enough

Method used

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  • Method for preparing submicron silver powder for electro-conductive paste
  • Method for preparing submicron silver powder for electro-conductive paste
  • Method for preparing submicron silver powder for electro-conductive paste

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preparation example Construction

[0023] The preparation method of submicron silver powder provided by the invention is divided into two steps:

[0024] The first step is the preparation of nano-silver particles: in the Ag + The concentration is 1×10 -4 mol / L~1×10 -2 In the mol / L silver salt aqueous solution, add the dispersant according to the mass ratio of the dispersant to the silver salt solute in the silver salt aqueous solution of 0.5:1~2:1, and use the cooling device to keep the system temperature at 5~10°C while stirring While adding an aqueous solution of reducing agent with a concentration of 1g / L~10g / L, the amount of reducing agent added is the same as that of Ag in the silver salt aqueous solution. + The molar ratio is 0.1:1~1:1, and the silver particle sol solution of 5~10nm is prepared.

[0025] The second step is the preparation of silver powder: to Ag + The concentration is 5×10 -3 mol / L~5×10 -1 Add the nano-silver particle sol solution prepared in the first step into the mol / L silver s...

Embodiment 1

[0028] Preparation of silver powder: Add 50 liters of deionized water into the reaction kettle, dissolve 450 grams of silver nitrate, keep the system temperature at 30°C, weigh 450 grams of ascorbic acid, 3 grams of glycerin and 1.5 grams of polyethylene glycol, and 2 liters of deionized Dissolve in water, keep the temperature at 30°C, slowly add it dropwise into the silver nitrate solution, drop it in about 30 minutes, and stir for another 10 minutes until the reaction is complete. Stop stirring, filter the suspension with suction, wash 5 times with 2 liters of deionized water, then wash 2 times with 500 ml of absolute ethanol, place in a vacuum drying oven, and dry at 70°C for 20 hours to obtain silver powder ,D 50 = 0.37 microns.

Embodiment 2

[0030] Preparation of nano-silver particles: Add 5 liters of deionized water into the reaction kettle, dissolve 1.8 grams of silver nitrate, add 1.8 grams of gelatin, dissolve, and cool the system to 5 °C with a cooling device; weigh 0.3 grams of sodium borohydride, dissolve in 100 milliliters of water is also cooled to 5° C., then quickly added to the silver nitrate solution, and stirred until the reaction is complete to obtain a sol solution of silver nanoparticles.

[0031] Preparation of silver powder: Add 50 liters of deionized water into another reaction kettle, dissolve 450 grams of silver nitrate, and add the above nano-silver particle sol solution as seeds during the vigorous stirring process, and keep the temperature of the system at 30°C; 450 grams of ascorbic acid, 3 grams of glycerin and 1.5 grams of polyethylene glycol were dissolved in 2 liters of deionized water, and the temperature was kept at 30°C, and slowly added dropwise to the silver nitrate solution for a...

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Abstract

The invention belongs to the field of electro-conductive paste and particularly relates to a method for preparing a submicron silver powder for the electro-conductive paste, comprising the step of adding a dispersing agent and a reducing agent into a silver salt aqueous solution to reduce the elemental silver. The method is characterized in that nano-silver particles are added into the silver salt aqueous solution before the dispersing agent and the reducing agent are added, wherein the nano-silver particles have the size of 5-10nm, and the addition amount of the nano-silver particles is 0.3-0.6 per mill of the mass of the silver salt which is the solute in the silver salt aqueous solution. The method is simple in process and has a low requirement for equipment. The raw materials are environmentally friendly and cause less pollution. The submicron silver powder prepared by adopting the method has uniform particle size and a narrow distribution range.

Description

technical field [0001] The invention relates to the field of conductive paste, in particular to a method for preparing submicron silver powder used in the conductive paste. Background technique [0002] Conductive paste has been widely used in various fields of the electronics industry such as wafer capacitors, potentiometers, thick film hybrid integrated circuits, sensitive components, and surface mount technology. Currently the most widely used silver conductive paste is silver as the conductive phase. Among them, silver exists in the conductive paste in the form of silver powder. The powder properties such as the shape, size, bulk ratio and fluidity of the silver powder have a decisive impact on the comprehensive performance of the conductive paste. Different preparation methods of the silver powder endow Silver powder has different powder characteristics such as shape, size, bulk ratio and fluidity. [0003] At present, the most common method of preparing silver powder...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/24
Inventor 叶志龙刘宗义
Owner SHENZHEN SENLONT ELECTRONICS
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