Catalytic impact of Sm2O3 nanoparticles on the electrodeposition of zinc-nickel alloy

Abstract

A variety of chemical compounds have been utilized as additives to develop the characteristics and the mechanical properties of electrodeposited zinc-nickel alloy plating. Zinc-nickel alloy plating was electrochemically deposited on a steel substrate from an acidic sulphate bath, containing Sm2O3 nanoparticles. The obtained results showed that the addition of small amounts of Sm2O3 causes a considerable shift in the polarization curve as well as the deposition potential towards greater noble potentials, demonstrating that Sm2O3 has a catalytic impact on Zn2+and Ni2+ reduction. The Ni content in the alloy was found to be 7.07–25.45 wt% depending on the operating conditions. The zinc-nickel alloy deposited electrochemically comprised of two phases, pure zinc, and Ni5Zn21, according to the XRD observations. The Sm2O3 incorporated in the Zn–Ni coating was detected using XPS (X-ray photoelectron spectroscopy) analysis. The data showed that zinc-nickel alloy coating prepared from an electrolyte containing Sm2O3 had a corrosion resistance higher than that prepared in its absence. On the other hand, the microhardness of zinc-nickel alloy plating was critically enhanced with Sm2O3 in the electroplating solution, it increased from 62.0 kg f mm􀀀 2 to 151.00 kg f mm􀀀 2. Changing the operating conditions such as temperature, pH, and current density have a considerable impact on the morphology of the zinc-nickel plating.