A study of hardness and grain size in pulse current electroforming of nickel using different shaped waveforms

This paper describes an experimental and theoretical study of the effects of different types of waveform on the grain size and the hardness of nickel electroforms in pulse current electroforming. The highest hardness value and the finest grain size were obtained using a ramp-down waveform with relaxation time. The experimental results show that compared with the conventional rectangular waveform and with relaxation time, the hardness value can be improved by about 28% when a ramp-down waveform, also with relaxation time, is used. These results are supported by theoretical predictions and the study of the surface morphology of the electroforms by scanning electron microscopy.