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Preparation method for wrapping surface of sheet-shaped silver powder with nano-silver particles

A technology of silver nanoparticles and nano-silver particles, applied in nanotechnology and other directions, can solve the problems of high surface activity of nano-silver powder, reduce the conductivity of paste, affect the sintering and contact of silver powder, and achieve low equipment requirements and improve the system. Compatible with dispersion, satisfying the effect of industrial production

Inactive Publication Date: 2019-05-21
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the large surface activity of nano-silver powder, it is easy to agglomerate and oxidize. Therefore, a large amount of organic dispersant is usually used to coat nano-silver powder. Although the antioxidant capacity and dispersibility of silver powder can be effectively improved, due to the introduction of a large amount of organic matter, It cannot be completely decomposed during the sintering process of the paste, which affects the sintering and contact of the silver powder, and instead reduces the conductivity of the paste

Method used

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  • Preparation method for wrapping surface of sheet-shaped silver powder with nano-silver particles
  • Preparation method for wrapping surface of sheet-shaped silver powder with nano-silver particles

Examples

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Effect test

Embodiment 1

[0023] Embodiment 1: a kind of preparation method coating silver nanoparticles on the surface of flaky silver powder, concrete steps are as follows:

[0024] (1) Dissolve silver nitrate and polyacrylic acid, a water-soluble dispersant, in deionized water, prepare a solution with a silver ion concentration of 1.0 mol / L, and a temperature of 40° C., a total of 70 ml, for subsequent use;

[0025] (2) Dissolve ascorbic acid in deionized water to obtain a reducing solution with a concentration of 0.8 mol / L and a temperature of 40°C, a total of 15 ml, and set aside;

[0026] (3) The standby (1) (2) solution is injected in the tubular reactor simultaneously, adds the commercially available nitric acid (mass concentration is 65~68%) of 15ml, stirs evenly, and the prepared side length is 0.6-1.0um, Monodisperse flaky silver powder suspension solution with a thickness of 20nm;

[0027] (4) Add 10% directional nucleating agent citric acid aqueous solution of remaining silver nitrate qua...

Embodiment 2

[0029] Embodiment 2: a kind of preparation method coated with silver nanoparticles on the surface of flaky silver powder, the concrete steps are as follows:

[0030] (1) Dissolve silver nitrate and polyacrylic acid, a water-soluble dispersant, in deionized water, and configure a solution with a silver ion concentration of 1.4mol / L and a temperature of 40°C, a total of 70ml, for subsequent use;

[0031] (2) Dissolve ascorbic acid in deionized water to obtain a reducing solution with a concentration of 1.0 mol / L and a temperature of 40° C., a total of 15 ml, and set aside;

[0032] (3) The standby (1) (2) solution is injected in the tubular reactor simultaneously, adds the commercially available nitric acid (mass concentration is 65~68%) of 15ml, stirs evenly, and the prepared side length is 0.8-1.2um, Monodisperse flaky silver powder suspension solution with a thickness of 40nm;

[0033] (4) Add 10% directional nucleating agent citric acid aqueous solution of remaining silver ...

Embodiment 3

[0035] Embodiment 3: a kind of preparation method coated with silver nanoparticles on the surface of flaky silver powder, the specific steps are as follows:

[0036] (1) Dissolve silver nitrate and polyacrylic acid, a water-soluble dispersant, in deionized water, and configure a solution with an ion concentration of 2mol / L and a temperature of 40°C, a total of 70ml, for subsequent use;

[0037] (2) Dissolve ascorbic acid in deionized water to obtain a reducing solution with a concentration of 0.8 mol / L and a temperature of 40°C, a total of 15 ml, and set aside;

[0038] (3) (1), (2) solution, inject in the tubular reactor simultaneously, add the commercially available nitric acid (mass concentration is 65~68%) of 15ml, stir evenly, preparation side length is 1.2-1.6 micron, thickness 50nm monodisperse flaky silver powder suspension solution;

[0039] (4) Add 10% directional nucleating agent citric acid aqueous solution of remaining silver nitrate quality in the silver powder ...

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Abstract

The invention discloses a preparation method for wrapping the surface of sheet-shaped silver powder with nano-silver particles, and belongs to the technical field of metal materials used for electronic slurry. A reducing solution is prepared by using ascorbic acid and a water-soluble dispersing agent; silver nitrate serves as a silver source; acid serves as a shape regulator; a mixed solution in quantitative ratio is subjected to a reduction reaction in a tubular reactor under the reaction temperature of 40 DEG C to obtain single-dispersion sheet-shaped silver powder with the side length of 0.8-1.2 microns and the thickness of 40 nanometers; then, an oriented nucleation agent solution and a certain numberof ascorbic acid reducing agent are added into a silver powder suspension solution, and the nano-silver particles directionally grow on the surface of the sheet-shaped silver powder; after the reaction is completed, an ethanol solution containing a surface modifier is added for rapid stirring for 30-60 minutes; and washing, filtering, drying and sieving are carried out to obtain the high-dispersion sheet-shaped silver powderwith the surface wrapped with thenano-silver particles. The sheet-shaped silver powder prepared by the preparation method is high in tap density, good in dispersibility and uniformity and high in sintering activity. Compared with traditional sheet-shaped silver powder, conductive slurry prepared by the silver powder can significantly reduce the volume resistivity, the thixotropy is good, and requirements for precise printing can be met.

Description

Technical field: [0001] The present invention generally relates to silver powder and methods of making the same. Background technique: [0002] Conductive silver paste is a viscous paste composed of high-purity metallic silver particles, binders, solvents, and additives. Conductive silver paste is usually screen-printed on substrates such as ceramic substrates or ITO films. After curing at a certain temperature, the solvent evaporates, and the resin adheres to the substrate to form a conductive network. Widely used in various fields such as integrated circuit assembly, electronic components, displays, touch screens, automotive electronics, medical treatment, and lighting communications. [0003] As electronic components tend to be miniaturized and densified, this requires silk screen circuits to have higher fine resolution and conductivity. The resistance of the slurry is mainly composed of the internal resistance of the filler, the contact resistance and the tunneling res...

Claims

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Application Information

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IPC IPC(8): B22F9/24B22F1/02B82Y40/00
Inventor 刘同心万剑卓宁泽王宏王海波
Owner NANJING UNIV OF TECH
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