Zinc Electrodeposition Morphology

Trejo etal. [225, 226] have also investigated the influence of several ethoxylated additives (ethyleneglycol and PEG polymers of different molecular weights) on the nucleation, growth mechanism, and morphology of zinc electrodeposited on GG from an acidic chloride bath. Results have shown that the presence of additives modifies the nucleation process and determines the properties of the deposits. 

The same mechanism of zinc electrodeposition on the GC electrode was observed in sulfate, chloride, and acetate ion solutions [227]. The anions mainly affected the nucleation densities during zinc deposition, which resulted in a different surface morphology. The nucleation rate constant was the same in the chloride and sulfate solutions and was equal to 1.22 x 10 s h In the presence of acetate and chloride ions, the deposited zinc film tends to grow in a multilayered pattern, while in sulfate solution, the zinc deposition forms irregular grains. A new approach to the estimation of zinc electrocrystallization parameters on the GC electrode from acetate solutions was described by Yu et al. [228]. 

B.K. Thomas and D.J. Fray, The Effect of Additiyes on the Morphology of Zinc Electrodeposited from a Zinc Chloride Electrolyte at High Current Densities , Journal of Applied Electrochemistry. Vol. 11, 1981,677-683. 

Bockris JO M, Nagy Z, Drazic DM (1973) On the morphology of zinc electrodeposited liom alkaline solutions. J Electrochem Soc 120 30-41... 

Cathode deposit morphology can also be affected by the presence of trace elements in solution. An SEM micrograph of a zinc deposit from a pure or unadulterated electrolyte and time duration of two minutes at 10 mA/cm2 is shown in Figure 3. When U0 parts per billion of antimony was added to this solution, and a similar electrodeposition cycle was performed, an approximate ten-fold increase in crystallite size was obtained (see Figure U). 

Electrodeposition on Other Electrodes Trejo et al. [224] have investigated the influence of the zinc chloride concentration on the zinc nucleation process on GC electrode in KCl solutions under conditions close to those employed in commercial acid deposition baths for zinc. The results show that the nucleation process and the density number of sites are dependent on ZnCh concentration. The deposits are homogeneous and compact, although a change in morphology is observed as a function of ZnCl2 concentration. 

Metal deposition and dissolution (34) In the electrodeposition of solid metals such as silver and zinc, the cation is transported across the electrochemical interface to sites on the electrode surface (Figure 6-4). The positive charge of the cation is offset by electrons from the metal, and the adsorbed species becomes an adatom. These species have surface mobility and migrate along the electrode surface to an imperfection such as a step dislocation, where they enter into the crystal lattice. In the absence of sufficient step dislocations to accommodate the rate of deposition, the adatom surface concentration increases until two- or three-dimensional nucleation occurs. The rate of such nucleation and surface migration strongly influences the morphology of the electrocrystalhzation process. The reverse of this process is involved with electrodissolution of crystalline electro-deposits. 

The main result of a more detailed investigation of Zn electrodeposition is that when intense hydrogen bubbling occurs at high potential or current density, the morphology of the ramified zinc deposit changes from dense-branching to fem-shaped dendrite [21]. The fern-shaped dendrite... 

M. Eyraud, A. Gamier, F. Mazeron, J. Crousier, Morphology and composition of electrodeposited zinc-manganese alloys. Plat. Surf Finish. 82 (1995) 63—70. 

Czerwinski F, Kondo K, Szpunar JA (1997) Atomic force microscopy study of surface morphology of zinc-iron electrodeposits. J Electrochem Soc 144 481-484... 

Kanagasabapathy M, Jayakrishnan S (2011) Textural and morphological studies on zinc-iron alloy electrodeposits. J Chem Sci 123 357-364... 

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