Sphere-like silver powder with particle size capable of being accurately controlled and preparation method thereof

Abstract

The invention provides sphere-like silver powder with particle size capable of being accurately controlled and a preparation method thereof. The method comprises the following steps: (1), mixing a nano-silver colloid with a dispersing agent solution to obtain a mixed solution, wherein the silver particles in the nano-silver colloid are approximately spherical; (2) under a stirring condition, dripping a silver salt solution and a reducing agent solution into the mixed solution in the step (1) in a parallel flow mode to react, so as to obtain silver powder slurry; and (3) carrying out solid-liquid separation, washing and drying on the silver powder slurry obtained in the step (2) to obtain the sphere-like silver powder. The silver salt solution and the reducing agent solution are dropwise added into the mixed solution of a dispersing agent and a seed crystal in a parallel flow mode to control the generation speed of elemental silver, so that the elemental silver uniformly grows on the provided nano-silver colloid seed crystal, the sphere-like silver powder with the particle size accurately controllable is obtained, and the reaction conditions are mild, normal temperature and normal pressure are achieved, equipment and process are simple, and the production period is short; it is easy to amplification and industrial application; the prepared silver powder is uniform in morphology,good in dispersity and high in tap density.

Description

technical field [0001] The invention relates to a preparation method of silver powder, in particular to a spherical silver powder whose particle size can be precisely controlled and a preparation method thereof. Background technique [0002] Silver powder has excellent electrical and thermal conductivity, and is widely used in the fields of solar cell paste, conductive adhesive and other electronic pastes. With the depletion of non-renewable resources such as oil and coal, and the enhancement of people's awareness of environmental protection, the development of new energy has attracted more and more attention, especially the development and utilization of solar energy has become a hot spot. Silver powder is the conductive phase of the silver paste of crystalline silicon solar cells, accounting for about 90% by mass in the silver paste, which has a great influence on the rheological properties and printability of the paste, and at the same time plays a decisive role in the ph...

AI Technical Summary

Problems solved by technology

This method has a long period, low crystallinity of silver powder, uneven appearance, narrow adjustable range of particle size, inability to precisely control particle size, complicated operation, and the need to complete the reaction in a certain pressure vessel and high temperature, which is not suitable for large-scale industrial production. There is a certain operational risk

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