THE INFLUENCE OF CO2+ CONCENTRATION ON THE PROPERTIES OF THE ELECTRODEPOSITED ZINC–COBALT ALLOY COATINGS

Abstract

The effects the concentration of cobalt on zinc-cobalt alloys obtained from sulphate baths under continuous current deposition are described. The deposit morphology was analyzed using Scanning Electron Microscopy (SEM) and an X-Ray Diffraction (XRD) was used to determine the preferred crystallographic orientations of the deposits. Protection against corrosion properties studied in a solution of 3 % wt NaCl in the potentiodynamic polarization measurements (Tafel), electrochemical impedance spectroscopy (EIS) to the potential of corrosion free. The parameters that characterize the corrosion behavior can be determined from the plots and Nyquist plots. It has been observed that the Zn–Co alloy is characterized by enhanced the resistance of corrosion compared to the Zn alloys and the addition of Co in the Zn-Co increases the micro-hardness, XRD and SEM results an identify any coatings Zn-Co alloy composition reveals that. zinc - rich ( η- phase) , cubic Co5Zn21 .