The effect of lead on zinc deposit structures obtained from high purity synthetic and industrial acid sulphate electrolytes

Effect of ionic liquid additive [BMIM]HSO4 on zinc electrodeposition from impurity-containing sulfate electrolyte. Part I: current efficiency, surface morphology, and crystal orientations

“…An increase in the concentration of lead to 10 mg dm -3 increases the peak intensities of the (100) and (002) planes, thus favoring growth in these directions. A similar observation is also reported by Mackinnon et al [13] who observed that increasing lead concentration in the zinc deposits progressively changed the orientations from (112) to (101) to (100) to finally a poorly shaped crystalline (002) structure. The crystal orientation is changed from (101), (100), and (002), as major planes for 10 mg dm -3 lead to an orientation dominated by the (101), (102), and (100) planes for combined addition of 5 mg dm -3 [BMIM]HSO 4 .…”

“…A CE of 92.0% is achieved with the addition of 10 mg dm -3 lead. Such increases in CE have also been observed by other researchers [13] and are observed generally because lead can readily co-deposit with zinc and the hydrogen overpotential on lead is higher than that on zinc, which leads to hinder the hydrogen evolution, and thus induces the zinc deposition process. The combination of 10 mg dm -3 [BMIM]HSO 4 and 10 mg dm -3 lead decreases the CE by *2% in contrast to the additive-free solution.…”

“…Cobalt and nickel [5,6,[9][10][11][12] which were difficult to remove from the electrolyte can cause mild redissolution of the zinc deposit, but this occurred only after an induction period that was dependent on the impurity concentration and on the zinc-to-acid ratio. Lead [13] had a small beneficial effect on the CE and exerted a grain-refining effect on the cathodic deposit with changing the orientation. Cadmium [7] did not affect the growth or orientation of the zinc deposit but reduced the deposit grain size.…”

Effects of 1-butyl-3-methylimidazolium hydrogen sulfate-[BMIM]HSO4 on zinc electrodeposition from acidic sulfate electrolyte

“…Leaching results in the formation of zinc sulfate in the aqueous sulfuric acid and the metal is then produced by electrodeposition [1]. However, electrodeposition of zinc is extremely sensitive to the presence of certain metallic impurities [2][3][4][5] in the electrolyte. Although high purity zinc metal can be electrodeposited from ultrapure zinc sulphate solutions, rigorous electrolyte purification is economically non viable.…”

Studies of micromorphology and current efficiency of zinc electrodeposited from flowing chloride electrolytes

“…The influence of added cadmium, iron and nickel chlorides on the current efficiency, and on the nature of the deposit, has been a subject of numerous investigations in the past (40,41,51,62,65). Only a modest effort was devoted to this problem area in the present investigation.…”