Electroplating and Corrosion study of Zn-Co, Zn-Fe and Zn-Co-Fe Alloys

Zn-co, zn-fe and zn-co-fe coatings were electrodeposited on mild steel from anacid sulphate bath, using thiamine hydrochloride (thc) and citric acid (ca) as additives.bath constituents and operating parameters were optimized by standard hull cell method, forpeak performance of the coatings against corrosion. the effect of current density (c.d.), phon the deposit characters, such as corrosion resistance, hardness, thickness, partial currentdensity and cce were studied and discussed. corrosion resistances were evaluated bypotentiodynamic polarization and electrochemical impedance spectroscopic (eis) method.corrosion resistance of the zn-co-fe coating under optimal c.d. (3.0 a dm-2) was found dueto its inherent high dielectric barrier, evidenced impedance signals. high partial currentdensity for zinc in zn-co-fe alloy coating supports the possibility of a synergistic catalyticeffect of co on fe and vice versa. x-ray diffraction study clearly indicates that a drasticchange in corrosion resistance of ternary alloy is due to the change in the phase structure ofthe coatings, compared to binary alloys. surface morphology and composition of the coatingswere examined by using scanning electron microscopy (sem), interfaced with energydispersive x-ray analysis (edxa) facility, respectively.