Modeling of electrocrystallization for pulse current electroforming of nickel

A mathematical model has been established for formulating the effect of different types of waveform on the three-dimensional electrocrystallization of nickel electroforms. The model describes how the different types of waveform influence the rate of three-dimensional nucleation, J, the rate of three-dimensional step growth via surface diffusion path, J(SD), and the rate of three-dimensional step growth via direct transfer path, J(DT) at the cathodic surface. Moreover, the dynamic electrocrystallization process including J, J(SD) and J(DT) was simulated. The highest maximum nucleation rate was obtained when a ramp-down waveform was employed. The highest step growth rate either via surface diffusion path or direct transfer path was obtained when conventional rectangular waveform was used. The best quality of electroforms, in terms of fine-grained structure, was found when a ramp-down waveform was employed. These results are in agreement with the findings of our previous studies. (C) 2001 Elsevier Science B.V. All rights reserved.