Structural and corrosion protection properties of electrochemically deposited nano-sized Zn-Ni alloy coatings

Zn-Ni alloy coatings were fabricated galvanostatically by applying varied current densities from 10 to 30 mA cm−2. Surface morphology of the coatings was examined with SEM. Crystal structure of the coatings was studied with X-ray diffraction spectroscopy (XRD). Compositions of the coatings were determined by atomic absorption spectroscopy (AAS). Corrosion protection properties studied using open circuit potential (OCP) measurements, potentiodynamic polarization measurements (Tafel), electrochemical impedance spectroscopy (EIS). Deposited alloy coatings were compact and nano-sized. Crystallite sizes of the coatings were varying from 26 nm to 36 nm. Nickel content of the samples were increased by increasing current densities and varied from 6.7 to 18.9 wt.%. Best corrosion protection performance was seen on the sample obtained at 30 mA cm−2. Our results are considerably encouraging for protection of mild steel against corrosion by obtained Zn-Ni alloys.