A systematic study of pulse and pulse reverse plating on acid copper bath for decorative and functional applications

Today industrial electroplating is mainly carried out using direct current even if the use of modulated currents could offer greats opportunities. Adjusting the amplitude and length of the current's pulses it is possible to control grain size, porosity and homogeneity of the deposits; the use of modulated currents could also decrease the environmental impact of deposition processes as they require a much lower percentage of organic additives. The aim of this work is to assess, through both theoretical and experimental investigation, how the deposition parameters affect the various characteristics of the deposit. We used a commercial acid copper bath for the depositions performing both pulse and reverse pulse sequences. The coatings have been characterised by estimating the deposition yield, homogeneity, hardness and reflectivity. Using pulsed currents, we obtained shinier and brighter films respect to those produced with stationary currents; the deposition efficiency was also improved. Bipolar currents, on the other hand, favour more homogeneous deposits over the entire deposition area, and are less affected by the edge effect.