Effect of Additives on Electrodeposition of Zinc from Alkaline Zincate Solution and Their Synergy Mechanism

The optimization and combination of additives are particularly important for the electrodepsotion of zinc in alkaline zincate solution. In this paper, the effect of NCZA (polyquaternium-2) and NCZB (sodium propargyl sulfonate) and the combination on the electrodeposition behavior of zinc and their synergy mechanism were systematically analyzed by potentiodynamic polarization, cyclic voltammetry, chronoamperometry, SEM and FT-IR. The results showed that the two additives had different effects on the electrodeposition of zinc. In the basic solution, the electrocrystallization of zinc followed the three-dimensional instantaneous nucleation. NCZB did not change the nucleation mechanism of zinc, and mainly played a leveling role. However, NCZA had a great inhibition effect on the electrodeposition of zinc and transformed the growth mechanism of zinc into three-dimensional continuous nucleation. When the two additives were combined, the adsorption effect on the electrode surface was stronger than that added alone, but no new substances were produced in the plating solution. The synergistic effect of the two additives enhanced the function of the characteristic groups on the electrode surface,which made the electrodeposition potential of Zn move significantly negatively, and the crystals of coating were more detailed and bright.