The influence of Chromium concentration on the corrosion resistance of the electrodeposited Zn–Co–Cr alloys

Electrodeposition operating conditions for Zn–Co–Cralloys from sulfate baths and the corrosion resistance of the electrodeposited alloys were studied. 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 3,5 % 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. X-ray diffraction studies of the deposit showed the presence of Co5Zn21 phase and η- phase. The obtained data also exposed that the corrosion resistance increases as a result of increasing Cr concentration and the addition of Cr in the Zn-Co increases the micro-hardness