Electrodeposition of Zn–Co alloys with pulse containing reverse current

The electrodeposition of Zn–Co alloy deposits was studied by means of pulse-plating technique. The surface morphologies of Zn–Co alloy deposits were examined using scanning electron microscopy (SEM), and an attendant energy dispersive X-ray analyser (EDA) was used to analyse the composition of Zn–Co alloy deposits. Results obtained showed that the average current density and reverse current density amongst all the variables investigated had very strong effects on the cobalt content in the Zn–Co alloy deposits. It is possible to electrodeposit Zn–Co alloy coatings with a very wide cobalt content range of 10–90 wt.% by modulating pulse parameters. Grain size, surface appearance and internal stress in the deposits were also improved significantly by introducing reverse current.