Preparation Of Ultrafine Dendritic Silver Powder By Electrolysis And Its Applicatio

With its low resistivity and large specific surface area,dendritic ultra-fine silver powder has unique physical and chemical properties and is widely used in the micro e-lectronics industry as well as in the field of printed electronics.With the continuous development of the electronics industry,dendritic silver powders are of great i m-portance and necessity to enhance the current performance requirements of conductive silver adhesives.Under the same quality conditions,dendritic silver powders have a higher bulk conductivity,a larger specific surface area and higher surface activity than flake or spherical silver powders and are therefore considered ideal fillers for silver conductive adhesives.In this paper,dendritic silver powders were prepared by electrolysis.The pr e-pared silver powders were characterised by X-ray diffractometer（XRD）,scanning electron microscope（SEM）,electrochemical workstation and thermogravimetric an a-lyser,and the effects of different process parameters on the physical properties of the silver powders were investigated.In addition,flake silver and dendritic silver powders were used as conductive fillers to prepare conductive silver glues to investigate the e f-fects of different morphological silver powders on the properties of silver glues and further investigate the effects of different surface treatment agents on the properties of silver glues,as follows:（1）The effects of silver ion concentration,temperature,current densi ty and ad-ditives on the physical properties of silver powder were investigated through si n-gle-factor tests.On the basis of the single-factor tests,the process of electrolytic silver powder electrical efficiency and energy consumption was optimized using the response surface method,and a mathematical model between electrical efficiency and energy consumption and the factors was obtained,and the optimum process was determined through the model:silver ion concentration of 8 g/L,temperature of 31.8°C,under the optimum process conditions,dendritic silver powders with a particle size of 3-4μm and good crystallinity were prepared with an average electrical efficiency and energy consumption of 80.1%and 803.4 k W·h/t Ag,respectively.（2）The influence of tartaric acid on the electrochemical behaviour of dendritic silver powders prepared by electrolysis was investigated.The results showed that the cathodic polarization increased and the overpotential increased with the increase of tartaric acid addition.Timed current results showed that the solution systems all fol-lowed a transient nucleation process,but the addition of tartaric acid affected the n u-cleation and growth kinetics of silver and inhibited cathodic polarisation.（3）To investigate the effect of different shapes of silver powders on the per- formance of silver glues,silver glues were prepared using silver flakes and dendritic silver powders as fillers,and the results showed that the silver glues doped with de n-dritic silver powders exhibited better electrical conductivity,and their volume resistiv-ity was reduced by 0.8×10^-3Ω·cm.The results show that the surface treatment agent type has a significant influence on the performance of the silver adhesive.The results show that the surface treatment agent type has a selective effect on the performance of the conductive adhesive,KI-treated conductive adhesive has better electrical conduc-tivity,and the dendritic silver powder-filled conductive adhesive shows the lowest line resistance（0.9Ω）,the oleic acid-treated conductive adhesive shows better mechanical properties,and the flake silver powder-filled conductive adhesive has better shear force（570 N）,for the conductive adhesive product R&D to provide technical support.