Study On The Preparation, Structure And Properties Of Cu/X/Ag Composite Powder

As a new type of composite material with excellent performance,silver-coated copper powder not only overcomes the shortcomings of electron migration in silver powder,but also takes into account the good physicochemical properties of copper powder and the good conductivity and oxidation resistance of silver powder.The purpose of replacing precious metals with base metals and reducing production costs is that silver-coated copper powders are widely used in electronic pastes for capacitors,integrated circuits,resistors,and various other electronic components.However,in the preparation process of silver-coated copper powder,oxidation resistance and bonding force have always been a technical problem,which severely limits the application of the obtained powder in medium and high temperature and slurry rolling.This paper uses chemistry for this problem.A Cu(core)/ X(intermediate layer)/ Ag(cladding)composite powder was prepared by a plating technique,and a composite powder having excellent oxidation resistance and good adhesion was obtained.In this paper,a spherical copper powder with a diameter of two micrometers is used as a base,and an intermediate layer of metal(Sn or Ni)is coated on the surface by electroless plating.After washing and drying,it is coated with a silver layer and passed through an X-ray diffractometer.XRD,scanning electron microscopy(SEM),energy dispersive spectroscopy(EDX),XPS,etc.were used to characterize the composite powder.The paper studied the different intermediate layer content,process parameters and subsequent heat treatment on the coating effect and The impact of performance.(1)Cu/Sn/Ag=40%/10%/50% composite powder and Cu/Ni/Ag=40%/10%/50%composite powder were successfully prepared by electroless plating.When the content of the intermediate layer is 10%,the composite powder has good morphology.The EDX spectrum and XRD show that the powder coating is completely dense and free of other impurities.The prepared Cu/Sn/Ag=40%/10%/50% composite powder and Cu/Ni/Ag=40%/10%/50%composite powder pine ratio and resistance are similar to ordinary silver-coated copper powder,which meets the needs of normal use.(2)Exploring the influence of different process parameters on the silver plating of composite powder,the results show that the deposition of silver plating layer is in the form of“island”,the silver ammonia solution and the reducing agent solution are simultaneously added and the concentration of reducing agent is added.When the composition was 25 g/L,0.5 g/L of dispersant was added and the reaction was carried out for 30 minutes,the composite powder had the best morphology.(3)The two composite composite powders were heat treated in different atmospheres and temperatures to investigate the effect of heat treatment on the adhesion and oxidation resistance of the powder.The experiment showed that the heat treatment affected the morphology of the two composite powders is not big,compared with ordinary silver-coated copper powder,the addition of the middle layer greatly improves the oxidation resistance of the composite powder,and the bonding force between the coatings after heat treatment is also greatly improved,which proves that the two powders They are excellent substitutes for ordinary silver-coated copper powder.