Preparation And Performance Study Of Highly Dispersed Cobalt-modified Chemical Copper-based Composite Powde

Ag-coated Cu powder is a kind of composite material that has good conductivity and oxidation resistance.It has broad application prospects in various industries,such as conductive paste,electrode material,high efficiency catalyst and antibacterial material.However,in the preparation of Ag-coated Cu powder by electroless plating,the surface energy of Cu powder is high and easy to agglomerate,which makes it difficult for Ag to coat it thoroughly,resulting in a decrease in the coating rate and oxidation resistance of the composite powder.The coating of transition Metal such as Co and Ni can effectively improve the oxidation resistance and corrosion resistance of Cu powder,and improve the activity of Ag plating.There is little research on Co-modified Ag-coated Cu composite powder.In this paper,the preparation method of highly dispersed Cu powder is discussed,the preparation process of Co modified Cu matrix composite powder is optimized,and the electroless Ag is carried out.It is expected that Ag coated Cu powder modified by Co plating with high dispersion,better oxidation resistance and corrosion resistance will be prepared.The dispersion of Cu powder was improved by physical dispersion such as UV irradiation,grinding and ultrasonic r.In the monodisperse experiment,UV irradiation for 20 min,grinding for 40 min and ultrasonic power for487.5 w all improved the dispersion of Cu powder.In the composite dispersion,the deposition of Cu powder was the highest and the particle size was the smallest after grinding for 40 min+Ultrasonic 487.5 w.The process of electroless Co plating was explored:under alkaline conditions,PVP 4 g/L,pH=9,DMAB dropping rate 10 m L/min,65℃plating for 30 min.Under acidic conditions,the mass ratio of Co:Cu=1:4,C₄H₄Na₂O₄ 10 g/L,Na H₂PO₂·2H₂O 30 g/L,PVP 4 g/L,pH=5,DMAB drop rate of 20 m L/min,plating at 70℃for 20 min.A Co layer was successfully coated on the surface of Cu particles under two conditions by SEM,EDS and XRD characterization.The Co²⁺content of two types of post-plating bath was tested,and the reduction rate of Co²⁺under acidic conditions was better than that of the other.The oxidation resistance of Cu powder and Cu@Co powder（pH=9/5）was tested with sintering at high temperature and the oxidation resistance performance of the powder was characterized by SEM,XRD and TG methods.The results show that under acidic conditions,the oxidation resistance of Co modified Cu powder is better,and the corrosion resistance is the best,and the specific surface area is the largest.Composite powder of electroless Ag plating on Cu with Co-modified and unmodified was observed and characterized.SEM and EDS analysis showed that Ag content in Co-modified Ag-coated Cu composite powder increased significantly.XRD shows that the composite powder has obvious peaks of Ag characteristics at room temperature,indicating that Ag is successfully deposited on the surface of the substrate.ICP analysis of Ag plating bath showed that there was a large amount of Co in Cu@Ag bath（pH=9/5）modified by Co.The results show that the Co layer departs and forms a stable complex with NH₃,which is dissolved in the Bath.The electrical conductivity test,which shows little difference in electrical conductivity,shows that the resistance of unmodified Cu@Ag powder is low.This may be due to the presence of Co trace in the Cu@Ag（pH=9/5）composite powder after Co modification.Co-modified Ag-coated Cu composite powder shows better performance in oxidation resistance and corrosion resistance tests under acidic conditions,and the particle size of co-modified Ag-coated Cu composite powder is obviously larger than that of Ag-coated Cu composite powder.The three Ag-coated Cu composite powders showed good antibacterial activity.After 30 days,the resistance change rate of Ag-coated Cu paste modified with co was the smallest,more stable and better anti-oxidation.To sum up,this paper discusses the physical dispersion method suitable for Cu powder,and the better technology of electroless Co plating modified Cu powder under alkali/acid condition,the surface morphology,phase composition and oxidation resistance of Co-modified Cu powderand Co-modified electroless Ag-plated composite powder were tested,which provided theoretical support and technical reference for the study of Cu-based composite powder.