Effect of Benzaldehyde on the Properties of Zinc-Nickel Alloy Electrodeposits from EDTA Bath

Zinc alloy coatings are considered as good substitutes for cadmium coating because cadmium is toxic in nature. Electrodeposition of Zinc-nickel alloy on mild steel is carried out from the electrolytic bath solution containing zinc oxide, sodium hydroxide and Nickel sulphate with EDTA as complexing agent. Plating process parameters such us current density, temperature and bath composition are optimized using galvanostatic electrolysis. The deposit obtained is uniform and semi bright. Zinc-nickel alloy is also electrodeposited from the bath solution containing various concentration of benzaldehyde. The deposits are uniform and bright the composition of nickel in the electrodeposits is studied by atomic absorption spectroscopy. Surface morphology of the deposit is studied by scanning electron microscopy and thickness of the deposit is determined by x-ray diffraction studies. Corrosion resistance measurement is done by tafel and impedance studies. It is observed that current efficiency and corrosion resistance of the zinc nickel alloy deposited specimen with benzaldehyde are greater than the deposited specimen without benzaldehyde.