Preparation,Characterization And Properties Of Silver-coated Copper Powder

Nowadays,hybrid metal powder in the electronic paste has attracted more attention because of the excellent electrical conductivity as well as economy and durability.Therefore,it is vital to find a strategy that meets these requirements,and silver-coated copper powder is just the right fit.In this paper,a series of studies on the preparation of silver-coated copper powder has been carried out,and then they have been applied to conductive pastes.A hybrid metal powder silver-coated copper powder has been prepared using replacement reduction method under nitrogen atmosphere,in which the spherical copper particles with 1 μm have been firstly synthesized by liquid phase reduction.Then,after the slurry prepared from the silver-coated copper powder has been sintered,the electrode resistance has been measured by a four-probe tester to characterize its electrical conductivity.The hybrid metal powder exhibits that the conductivity gradually increases as the silver content increases.Besides,it is found that the sintering temperature has a great influence on the sheet resistivity of the film electrode prepared by the silver-coated copper powder.When the sintering temperature is 500 ℃,the sheet resistivity is the smallest,and the electrode resistance was only 0.02 Ω·cm/□ when the actual silver content was 59.87 wt%.In addition,the effects of different surface treatment agents on the properties of silvercoated copper powder has been investigated.For example,polydopamine,oleic acid,oleic acid amide,polyethylene glycol and so on.As a consequence,the oxidation resistance of oleic acid is the best.It is prominent that only 6% weight gain rate of the oleic acid-coated silver-coated copper powder has been discovered when the silver content is 39.61 wt%.Afterwards,the oxidation resistance and electrical conductivity of oleic acid-coated silver-coated copper powder with different silver content have been researched.It is demonstrated that the electrode resistance is 11.4 Ω·cm/□,0.5 Ω·cm/□,0.11 Ω·cm/□,and 8.8 mΩ·cm/□ when the silver content is 28.32 wt%,39.61 wt%,51.22 wt%,and 59.87 wt%,respectively.Finally,the properties of conductive paste prepared by silver-coated copper powder have been investigated.The influence of different glass powders,different sintering temperatures,and different content of glass powder or silver on the conductivity of conductive paste has been reported in detail.The results show that the square resistance of the electrode decreases first and then increases with the increase of sintering temperature.When the glass powder content is increased,the electrode resistance gradually decreases from 257.6 mΩ·cm/□ with 1.5 wt% to 5.4 mΩ·cm/□ with 4.5 wt%.Moreover,as the silver content in the silver-coated copper powder increases,the corresponding electrode square resistance decreases.When the silver content was 59.87 wt%,the electrode resistance is 0.03 mΩ·cm/□.