Kinetics of Ni/Nano-SiO2 Codeposition on the Sintered NdFeB Surface

The Ni/nano-SiO2 composite coating was applied on the surface of sintered NdFeB samples using the electrocodeposition method to evaluate the corrosive resistance of this material. The effect of current density and silica concentration in the solution on the nanosilica content in the coating was analyzed with EDS. With an increase in current density, the SiO2 content in the coating increases correspondingly to 1.5 A/dm2, then decreases with its further increase. The SiO2 content in the coating increases gradually with the SiO2 content in the plating solution. If the SiO2 concentration in the plating bath is higher than 15 g/l, its content in the coating decreases with the SiO2 concentration in the solution. The kinetic model of the nanosilica codeposition is constructed on the basis of the Guglielmi theory. The concentration model of neutral silica particles on the cathode surface during the electrocodeposition process is built up, using the Guglielmi theory and particle transfer concept, which creates the basis for the development of the nanocodeposition approach and technology.