Blocky superfine silver powder and preparation method and application thereof

Abstract

The invention belongs to the field of manufacturing of special metal functional powder, and relates to blocky superfine silver powder and a preparation method and application thereof.The preparation method comprises the steps that a soluble silver source, an ester protective agent and a saccharide reducing agent are selected and matched with an alcohol aqueous solution to serve as a solvent, a precursor solution is prepared and subjected to a chemical reduction reaction, and the blocky superfine silver powder is obtained; the block-shaped superfine silver powder is prepared in one step, pH adjustment is not needed, the preparation process is simple, repeatability is high, the production scale can be multiplied, and therefore the production efficiency is greatly improved, and the quality of large-scale production is stable; the yield of the blocky superfine silver powder prepared by the preparation method can be up to 96%, the dispersity is excellent, the average particle size is 2-6 microns, the tap density can be up to 5.1 g/cm < 3 >, the resistivity of the obtained blocky superfine silver powder is as low as 0.000022 omega.cm, and the blocky superfine silver powder is an ideal material for producing conductive silver paste and photovoltaic silver paste.

Description

technical field [0001] The invention belongs to the field of manufacturing special metal functional powders, in particular to a massive superfine silver powder and a preparation method and application thereof. Background technique [0002] As one of the important renewable energy sources, solar energy has gradually become the focus of new energy research in the world due to its non-polluting, large reserves and sustainable application characteristics. According to reports, solar cell power generation will occupy an important position in the future global energy layout. As an effective way to replace traditional energy, its proportion is expected to gradually occupy the main position of the global energy composition. It is estimated that by 2040, renewable energy will account for more than 50% of the world's total energy, and solar cell power generation will account for more than 20%. It is estimated that by the end of this century, solar cell power generation will account f...

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Problems solved by technology

[0005] CN102632248A discloses a spherical silver powder and a preparation method thereof, in which L-ascorbic acid is used as a reducing agent and polyvinylpyrrolidone is used as a protective agent, and a spherical silver powder with a particle size of 1 to 3.5 μm is obtained from a silver nitrate solution of a reaction raw material by a chemical reduction method. Ultrafine silver powder, but it is necessary to control the pH value of the whole reaction between 3 and 6 by dropping ammonia water during the whole reaction process, so that the rate of silver nitrate reduction reaction remains stable, which increases the complexity of the method, and at the same time This process can produce poisonous nitrous acid gas, which is easy to cause pollution to the environment; CN105234426A discloses a preparation method of ultrafine nano-silver, which configures silver nitrate solution, polyethylene glycol dispersion and ammonium formate reducing agent solvent respectively, and then After the three solutions are mixed, the nano-scale spherical ultrafine silver powder with a particle size of 50-100nm can be obtained through chemical reduction reaction.

[0006] However, compared with spherical ultrafine silver powder, flake and block ultrafine silver powder have more advantages in conductive silver paste. They not only have lower specific surface energy, stronger oxidation resistance, and more stable structure, but also have many advantages during use. Forms surface and / or line contacts, resulting in lower contact resistance and higher conductivity

However, at this stage, the preparation of flake and block ultrafine silver powder still mainly depends on the mechanical ball milling method. The disadvantage of this method is that it is easy to introduce impurities, poor repeatability and low efficiency.

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