Evaluation of the effect of deposition bath glycerol content on zinc–nickel electrodeposits on carbon steel

Zn–Ni electrodeposits have been used to improve the corrosion resistance of carbon steel substrates in several applications, mainly in the aeronautical, oil, gas, and automotive industries. The use of component compounds that increase deposition efficiency and corrosion resistance has attracted growing interest. In this study, the effect of glycerol bath content (to a concentration of 0.34 mol/L) in bath deposition was analyzed. The deposition efficiency was analyzed by galvanostatic and potentiodynamic deposition, and the corrosion resistance was estimated with electrochemical tests, and mass loss measurements. The deposits were characterized by X-ray fluorescence, X-ray diffraction, and scanning electron microscope. The results indicate that there is a significant increase in the deposition efficiency and corrosion resistance when using glycerol concentrations up to 0.07 mol/L. For glycerol concentrations between 0.14 and 0.34 mol/L, there is a decrease in the deposition efficiency, and these concentrations do not result in a clear increase in the corrosion resistance of the Zn–Ni deposit. Analysis of the effect of deposition bath glycerol on the deposition efficiency and corrosion resistance of a Zn–Ni alloy indicates that this effect is related to the morphology of the deposit. The addition of glycerol to the deposition bath solution deposition results in grain refinement and the formation of a more compact deposit.