Control of zinc plating solutions, determining the optimum concentration of thiourea additive by electrochemical techniques

摘要

In this work we have analyzed the effect of thiourea concentration in the acid zinc deposition process. For these purpose, we have used the electrochemical techniques (cathodic voltammetry and Electrochemistry Impedance Spectroscopy, EIS). It allows determining the optimal concentration thiourea additive. In this range, we have obtained better finishes, more refined and decoratives layers. We have found in voltammetric studies that the electroreduction of Zn 2+ in the presence of thiourea is accelerated. The EIS studies has shown the “electrodeposition resistance” decrease in the presence of thiourea. The addition of more thiourea in the solution, in the optimum concentration, the electrodeposition resistance to the electrodeposition process is increased. The main contribution of this research and its scientific contribution is the use of electrochemical techniques for determining the optimal concentration of thiourea additive in the zinc electroplating solution in chloride acid media