Study Of External Magnetic Field On The Process Of Electroless Plating In Different Substrate Materials

As an important technology of material surface modification, electroless plating has got high attention from people because of convenient operation, simple device, uniform coatings and low cost. So there is a great significance to research and develop the electroless plating process and improve coating performance.Magnetic field affected the movement of microscopic particles, so as to affecte the physical and chemical reaction in the process of materials synthesis. It also could change physico-chemical properties of material in the process of reaction and provok new reaction phenomenons, at the same time, the product got new structure characteristic and function. Therefore introducing magnetic field in electroless plating process to explore the effection of magnetic field to REDOX reaction in the process of electroless plating and the effection to coating performance has greatly practical significance and theoretical value.This paper explored the influence of electroless plating based on different substrate material by applying an external magnetic field. By changing the nature of the external magnetic field and application method the experiments were conducted under the standard of magnetic field direction or intensity etc and different electroless plating formula. The coating properties were studied by microhardness tester,metallographic microscope, automatically scratch device for coating bonding strength, scanning electron microscopy(SEM) and energy dispersive X-ray(EDS). According to changes of the coating performance the magnetic effect mechanism was discussed and the better electroless plating process route was confirmed.The results shown that magnetic field has obvious difference effects between iron based materials electroless plating and copper based material electroless plating.(1)Both static magnetic field and alternating magnetic field could promote the deposition rate of elelctroless plating on iron substrate, while deposition rate of copper substrate electroless plating has been less affected. Only when the samples were perpendicular to static magnetic field the deposition rate was accelerated.(2) The influence of magnetic field on the coating surface morphology was different. Static magnetic field increased the complexing rate of nickel ion in plating solution so as to refine the surface morphology of the coating. On the contrary alternating magnetic field could reduce the complexing rate of nickel ion in plating solution and lead to more obvious drum cellular morphology of the coating. When applied a homogeneous magnetic field, coating surface of copper substrate appeared obvious orientation.(3) The static magnetic field has influence on the bonding strength between coating and substrate while alternating magnetic has no effect to it. The bonding strength between copper substrate and coating was influenced not only in static magnetic field or alternating magnetic field, at the same time the effect was more obvious.(4) External magnetic field also has some influences to other properties of the coating such as the coating hardness, coating magnetic property and so on.