Effects of duty cycle on electrodeposition behaviour of Ni-SiCp composite coatings

Ni-SiCp composite coatings were synthesised by pulse electrocodeposition with different duty cycles. The grain size and the SiC particle content were found to increase with increasing duty cycle, and a maximum microhardness value was obtained at a duty cycle of 50%. Based on the results of electrochemical impedance spectroscopy, an equivalent circuit model was used to estimate the charge transfer current of the electrodeposition process at different duty cycles. The peak charge transfer current was found to decrease with increasing duty cycle. An analytical volume fraction equation was also applied to predict the content of embedded SiC particles in the composite coatings. The trend of the predictions was in consistent with the experimental results.