Corrosion characteristics of composite coatings of cobalt on steel are discussed in this paper. Particulate strengthened cobalt composites with PSZ (partially stabilized zirconia) were electro codeposited on steel substrate from sulphate bath at room temperature. Composite coatings showed more noble potential values and better corrosion resistance than pure cobalt coatings in non-deaerated sodium chloride solution. However, when galvanically coupled to steel in a similar medium the composites induced much less corrosion of steel than cobalt. Galvanic current and dissolution current determination indicated a linear variation with cathode to anode area ratio, which at higher values approached equality. A logarithmic variation was, however, observed for galvanic potential with the same. Composites had better passivation characteristics than cobalt in 1N sulphuric acid.