Method for preparing spherical silver powder

A technology of silver powder and silver nitrate, which is applied in the field of silver powder, can solve the problems of low concentration of silver nitrate, uncontrolled reaction process, difficulty of silver paste on solar front grid, etc., and achieve narrow particle size distribution, low environmental pollution and good sphericity Effect

Inactive Publication Date: 2015-03-11
中国船舶重工集团公司第七一二研究所
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The tap density of silver powder obtained by the method of the invention is between 4.7-5.8 g / cm3, but the concentration of silver nitrate in the wet process step is too small, the reaction process is not controlled, and after screening treatment The maximum particle size is still more than 10 μm, and it is difficult to apply it to the solar front grid silver paste

Method used

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  • Method for preparing spherical silver powder
  • Method for preparing spherical silver powder
  • Method for preparing spherical silver powder

Examples

Experimental program
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Effect test

Embodiment 1

[0023] Preparation of silver nitrate solution: Add 15Kg of silver nitrate crystals into container A with a volume of 200L, add deionized water until the liquid level reaches the 160L mark, stir to dissolve the silver nitrate crystals, add 255g of polyvinyl alcohol dissolved in 2L of deionized water solution, and then (NH 4 ) 2 SO 4 solution (50g / L) to adjust the pH of the silver nitrate solution to 5.5, keep the solution temperature stable at 30±2°C, and keep stirring; prepare ascorbic acid solution: add 13.5Kg ascorbic acid to container B with a volume of 500L, and add deionized water to the liquid level When the ascorbic acid reaches the 160L mark, stir and dissolve the ascorbic acid, the temperature of the solution is stable at 30±2°C, keep stirring; add the solution in container A to container B, stir vigorously with a high-shear emulsifier until the reaction is fully complete, then lower it to sink. Wash the precipitate obtained by the reaction with deionized water, dr...

Embodiment 2

[0025] Preparation of silver nitrate solution: Add 15Kg of silver nitrate crystals into container A with a volume of 200L, add deionized water until the liquid level reaches the 160L mark, stir to dissolve the silver nitrate crystals, add 300g of polyvinylpyrrolidone dissolved in 2L of deionized water solution, and then (NH 4 ) 2 SO 4 solution (50g / L) to adjust the pH of the silver nitrate solution to 6, keep the solution temperature stable at 25±2°C, and keep stirring; prepare ascorbic acid solution: add 13.5Kg ascorbic acid to container B with a volume of 500L, and add deionized water to the liquid level When the ascorbic acid reaches the 160L mark, stir and dissolve the ascorbic acid, the temperature of the solution is stable at 25±2°C, keep stirring; add the solution in container A to container B, stir vigorously with a high-shear emulsifier until the reaction is fully complete, then lower it to sink. Wash the precipitate obtained by the reaction with deionized water, d...

Embodiment 3

[0027] Preparation of silver nitrate solution: Add 15Kg of silver nitrate crystals into container A with a volume of 200L, add deionized water until the liquid level reaches the 160L mark, stir and dissolve the silver nitrate crystals, add 150g of polyvinyl alcohol and 2L of deionized water to dissolve 120g gelatin solution, then use (NH 4 ) 2 SO 4 solution (50g / L) to adjust the pH of the silver nitrate solution to 5.8, keep the solution temperature stable at 35±2°C, and keep stirring; prepare ascorbic acid solution: add 13.5Kg ascorbic acid to container B with a volume of 500L, and add deionized water to the liquid level When the ascorbic acid reaches the 160L mark, stir and dissolve the ascorbic acid, the temperature of the solution is stable at 35±2°C, keep stirring; add the solution in container A to container B, stir vigorously with a high-shear emulsifier until the reaction is fully completed, then lower it to sink. Wash the precipitate obtained by the reaction with d...

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Abstract

The invention provides a method for preparing spherical silver powder. The method comprises the following steps of (1) weighing silver nitrate, and adding deionized water to prepare a silver nitrate solution with the silver ion concentration of 50-100g/L; (2) adding an organic dispersing agent into the silver nitrate solution, and uniformly mixing, wherein the weight of the organic dispersing agent is equal to 1%-5% of the weight of the silver nitrate; adding (NH4)2SO4 (ammonium sulfate) solution with the concentration of 150-250g/L, and adjusting the pH (potential of hydrogen) value to 4-6.5, so as to obtain a first water solution; (3) weighing ascorbic acid, and preparing into a reducing solution with the ascorbic acid concentration of 70-90g/L; (4) adding the reducing solution into the first water solution, and mixing, wherein the ratio of usage amounts of the first water solution and the reducing solution is 0.8:1; controlling the reaction temperature at 15-35 DEG C, using a high-efficiency stirrer to stir, and reacting for 15-20min, so as to obtain reaction sediments; (5) using the deionized water to wash the sediments, filtering and drying the sediments to obtain the dry silver powder, and then loading the dry silver powder into a high-speed rotary vibration powder sifting machine to disperse, so as to obtain the silver powder with high tap density.

Description

technical field [0001] The invention relates to the field of silver powder, in particular to a preparation method of spherical silver powder. Background technique [0002] With the development of electronic technology towards high reliability and refinement, technologies such as printed circuits require denser and more precise circuits. To meet these needs, wires printed from electronic pastes and cured or sintered have become narrower in width and closer in distance between wires. The silver powder required to form tightly packed, fine, narrow wires must be a dense, ultrafine spherical powder. For example, the front grid silver paste used on silicon solar cells, in order to achieve the required photoelectric conversion efficiency, in addition to ensuring good ohmic contact of the grid silver line after firing, it is also required that the silver paste has good printing performance. To ensure that the surface of the silver layer is flat and dense, without obvious defects a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/24B22F1/00
Inventor 周彩荣石磊龚强李代颖柳忠琪
Owner 中国船舶重工集团公司第七一二研究所
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