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. (c) 2004 Elsevier Ltd. All rights reserved.