Method for preparing ultrafine silver powder by directly performing thermal decomposition on silver nitrate

A technology of ultra-fine silver and silver nitrate is applied in the preparation of ultra-fine silver powder, and in the field of preparing ultra-fine silver powder by direct thermal decomposition of silver nitrate, which can solve the problems of high pyrolysis temperature, unable to obtain silver powder, poor monodispersity and the like, and achieve purity High, good product quality, high tap density

Inactive Publication Date: 2012-07-04
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The silver powder formed under high supersaturation has severe agglomeration, poor monodispersity, low crystallinity, and low tap density, which is difficult to meet the requirements for preparing front silver paste for crystalline silicon solar cells
Usually, the pyrolysis temperature of silver nitrate direct pyrolysis is relatively high, which leads to the easy sintering of silver powder and forms lumps or flakes, so that silver powder cannot be obtained.

Method used

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  • Method for preparing ultrafine silver powder by directly performing thermal decomposition on silver nitrate
  • Method for preparing ultrafine silver powder by directly performing thermal decomposition on silver nitrate
  • Method for preparing ultrafine silver powder by directly performing thermal decomposition on silver nitrate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Put the crucible containing 40g of silver nitrate solid into a tube furnace, heat it to 440°C at a heating rate of 5°C / min, and feed air with a relative humidity of 80-85%, and the air flow rate is 400-500ml / min , After calcination for 6 hours, stop heating and ventilating, cool to room temperature, collect the solid product in the crucible, and obtain the superfine silver powder product. The X-ray diffraction analysis spectrum of gained silver powder is as figure 1 As can be seen from the figure, except for the characteristic peak of silver, there is no other impurity phase, and the characteristic peak of the sample is narrow and sharp, indicating that the obtained silver powder has a high degree of crystallinity. The scanning electron microscope photograph of gained silver powder is as figure 2 As shown, it can be seen from the figure that the appearance of the obtained silver powder is a spherical particle, and the average particle size is about 1.5um.

Embodiment 2

[0024] Put the crucible containing 40g of silver nitrate solid into a tube furnace, heat it to 520°C at a heating rate of 20°C / min, and feed air with a relative humidity of 85-90%, and the air flow rate is 600-800ml / min , after calcining for 4h, stop heating and ventilating, cool to room temperature, collect the solid product in the crucible, obtain the ultrafine silver powder product and get the scanning electron micrograph of the silver powder as follows image 3 As shown, it can be seen from the figure that the appearance of the obtained silver powder is a spherical particle, and the average particle size is about 0.8um.

Embodiment 3

[0026] Put the crucible containing 40g of silver nitrate solid into a tube furnace, heat it to 400°C at a heating rate of 35°C / min, and feed air with a relative humidity of 80-85%, and the air flow rate is 200-300ml / min , After calcination for 8 hours, stop heating and ventilating, cool to room temperature, collect the solid product in the crucible, and obtain the superfine silver powder product. The appearance of the obtained silver powder is spherical particles, and the particle size of the silver powder is 1.2um.

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Abstract

The invention discloses a method for preparing ultrafine silver powder by directly performing thermal decomposition on silver nitrate. The method comprises the following steps of: putting a crucible with a silver nitrate solid into a tubular furnace, heating to temperature of between 400 and 550 DEG C at heating speed of between 5 and 50 DEG C/min, and introducing air with the relative humidity of between 80 and 100 percent, wherein the air flow is of between 200 and 800 ml/min; calcining for 2 to 8 hours, stopping heating and introducing the air; and cooling to room temperature, collecting solid products in the crucible, and thus obtaining the ultrafine silver powder with the average particle size of between 0.5 and 2 mu m. According to the method, reducing agents and aids are not required. The process is simple, and is low in cost; and the obtained silver powder is similarly spherical particles, has high purity, high crystallinity and relatively high compaction density, and is suitable for conductive slurry industries.

Description

technical field [0001] The invention relates to a method for preparing ultrafine silver powder, in particular to a method for preparing ultrafine silver powder by direct thermal decomposition of silver nitrate, and belongs to the technical field of metal powder preparation. Background technique [0002] Silver powder is widely used in the electronics industry due to its excellent electrical and thermal conductivity and strong resistance to zinc oxide. As the basic material of thick-film electronic paste, silver powder has always been a research hotspot in its preparation technology, especially the rise of the solar energy industry, which has led to a sharp increase in the consumption of silver powder in various related fields, but also put forward higher requirements for the performance of silver powder. Such as spherical or quasi-spherical morphology, monodisperse, high tap density, etc. [0003] There are many preparation techniques for silver powder, mainly atomization m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/30
Inventor 刘志宏李启厚李玉虎刘智勇何仕超张旭
Owner CENT SOUTH UNIV
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