Preparation method for high-conductivity nanometer silver-coated copper thick film paste capable of being sintered in air

Abstract

Disclosed is a preparation method for high-conductivity nanometer silver-coated copper thick film paste capable of being sintered in air. The preparation method at least comprises the steps of (A), performing corrosive wash on metal copper powder; (B), dissolving the corrosively washed metal copper powder into ethylene glycol to form a metal copper solution, and dissolving metal silver powder into ethylene glycol to form a metal silver solution; (C), performing mixing on the metal copper solution and the metal silver solution to form a metal mixed solution, and performing a chemical replacement reaction in the metal mixed solution to enable free silver ions of the metal silver to move to the surface of the corrosively washed metal copper powder to be reduced to the nanometer silver state to form a layer of nanometer silver on the surface of the corrosively washed metal copper powder; (D), performing filtering and drying on the metal mixed solution to take nanometer silver-coated copper powder; and (E), performing sintering on the nanometer silver-coated copper powder in a non-reduction atmosphere, and sintering the surface nanometer silver into a molten state before the metal copper powder is oxidized to coat the metal copper powder with the molten nanometer silver to obtain the silver-coated copper thick film paste.

Description

technical field [0001] The present invention relates to a preparation method of a high-conductivity nano silver-coated copper thick film paste that can be sintered in air, especially a kind of nano-silver-coated copper particles that can be sintered in air and at low temperature to obtain high conductivity. The preparation method of copper-clad thick film paste, especially refers to the preparation method of thick film conductive paste that achieves low cost, low resistance, low temperature sintering (or high temperature sintering depending on application requirements), high thermal conductivity, and does not require sintering in reducing atmosphere. Background technique [0002] Thick-film conductive paste can be divided into high-temperature system using glass and low-temperature system using polymer resin. High-temperature sintered conductive paste achieves liquid sintering through glass melting to sinter metal particles and conductors together to improve electrical condu...

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Problems solved by technology

However, copper has a strong oxidation potential energy, and it is prone to oxidation during the preparation and application process, which reduces its conductivity. Therefore, it needs to be prepared under nitrogen with an oxygen partial pressure lower than 10ppm, and the conductivity of copper electrodes will decrease with sintering. ) increases with increasing temperature

[0004] For general thick film copper paste, regardless of the sintering temperature, metal copper particles are prone to oxidation in the air, so it must be sintered in a reducing atmosphere to avoid copper oxidation, and sintering at a high sintering temperature can obtain high conductivity , if the copper paste is sintered at a low temperature, it will have the disadvantage of greatly reducing its conductivity due to the presence of some non-conductive resin

[0005] Since silver is a precious metal, metal copper is chosen as the material in order to reduce the material cost. However, if the copper paste needs to be sintered in a reducing atmosphere, the process cost will increase, and the low-temperature sintered copper paste is connected by polymer resin, resulting in low conductivity; therefore, Generally, those who have used it cannot meet the needs of users to solve the problems of low conductivity and easy oxidation of low-temperature copper paste in actual use.

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