The effect of the technical parameters in composite brush electroplating on the deposition and the properties of coating such as the content of particles, microhardness and wear resistance had been investigated in Ni/SiO_2 and Cu/Al_2O_3 system. The optimal operation and variables were obtained. The experiment showed that the common brush electroplating using the graphite anode prepared the metal/graphite composite coating acturally. In present work it was also successful to brush the composite coating of Ni-P/BaF_2, Cu/BC, Ni/Al_2O_3 and Cu/SiO_2 etc.. The key of formation of the brush composite coating was the suspension and dispersion of particles in plating solution continuously. The surfactant in solution plays an important role in suspension and dispersion of particles. The influence of surfactant on suspension of particle was studied in this work and how to prepare the brush plating solution of Cu/Al_2O_3 and Ni/SiO_2 was developed. It has been deduced that the surfactant could form the adsorption film on the interface, decrease the energy of the system, increase the surface charge of particles and raise the viscosity of plating solution. The adsorption of surfactant on the surface of particles and electrode was proven by the potential change, polarization curve and AC impedance. No obvious influence on the properties of coating was observed. The process of brush electroplating and the difference between brush and bath plating (electro and electroless plating) were discussed. The results of experiments show that the speed of relative movement of anode and cathode, the character of particles are two important parameters in brush plating of composite coating. The composite ability of particles in brush plating is less than that in bath (electro and electroless) plating.
修改评论