Cleaning method for micron-sized flake silver powder

Abstract

The invention provides a micron-sized flake silver powder cleaning method which comprises the following steps: mixing silver nitrate, a reducing agent and a water repellent agent, and reacting to obtain a reaction product; dehydrating the reaction product until the mass content of silver powder is greater than or equal to 95%, and adding ethanol for slurrying treatment; and adding an iodine compound under an ultrasonic condition, shearing and washing at 1500-2500rpm, carrying out solid-liquid separation, and drying to obtain the micron-sized flake silver powder. According to the method, the hydrophobic agent such as oleic acid is used for conducting hydrophobic treatment on the surface of the silver powder in the reaction process, the interaction force between the silver powder is changed, the surface free energy of silver powder agglomeration is washed and broken in a high-speed shearing mode, the dispersity of the silver powder in an oily system is reasonably improved, and the impedance of the silver powder is reduced. The impedance of the silver powder obtained by cleaning through the cleaning method provided by the invention can be reduced by 10-20%; and the impedance reaches 170 ohms.

Description

technical field [0001] The invention belongs to the technical field of precious metal cleaning, and in particular relates to a cleaning method of micron-scale flaky silver powder. Background technique [0002] Low-impedance micron-scale flake silver powder is an important raw material for preparing conductive silver paste for circuit boards. At present, the research on micron-scale flaky silver powder mainly focuses on the synthesis method, the coordination of reaction devices, and the control of reaction conditions, but there are few studies on the post-treatment steps after the synthesis of silver powder. The D50 of micron-sized silver powder is generally concentrated at 3-5 μm, and the surface energy is large, so it is very easy to agglomerate. [0003] The traditional silver powder cleaning method adopts centrifugation, stirring and soaking, which cannot fully break the agglomeration of flake silver powder. The agglomerated particles make the micron-sized silver powder ...

AI Technical Summary

Problems solved by technology

[0003] The traditional silver powder cleaning method adopts centrifugation, stirring and soaking, which cannot fully break the agglomeration of flake silver powder. The agglomerated particles make the micron-sized silver powder form a dense bond in the silver paste, resulting in increased impedance and poor electrical conductivity.