Study of dendritic growth of zinc crystals on the edges of steel sheet

Abstract

In this paper, the formation of zinc dendrites at the strip edge of an industrial electrogalvanizing line was studied. For that purpose, a rotating washer electrode was designed to reproduce the hydrodynamic conditions and the current density distribution found in the industrial process. Polarization curves were recorded at different rotation speeds in order to investigate the electrokinetic behavior of the cathodic process. The induction time for dendritic growth was estimated for different overpotential values and the existence of a minimum overpotential below which dendrites do not grow was confirmed. Dendrite precursors on the edge of the washers were well characterized and its birth and precise location were studied. The general model of disperse and dendritic metal electrodeposit formation derived by Popov et al. was used to explain the effect of electrolyte zinc concentration, rotation speed of the cathode, electrolyte temperature and edge roughness on the size and morphology of dendrites. The results showed that this theory provides an accurate description of the phenomenon even for non-stationary electrodes, which have not been extensively studied so far. The experimental setup proved to be a powerful means to study the formation of dendritic growth of zinc crystals on the edges of steel strip and is well suited to characterize other metals that produce this type of defect.

Suppressing the dendritic growth of zinc in an ionic liquid containing cationic and anionic zinc complexes for battery applications

“…Earlier results in the literature showed that zinc dendritic growth preferentially occurs at the edges and along the boundaries of the electrode where the current density is higher compared to the center. 54,55 Therefore, the morphologies of the zinc deposits obtained at the edge and at the center region of the deposits in the electrolytes of 1.5 M ZnO/IL, 0.4 M Zn(TfO) 2 /IL and (0.4 M Zn(TfO) 2 + 1.5 M ZnO)/IL at −1.8 V for 2 h, respectively, were investigated by scanning electron microscopy (SEM). The images are shown in Fig.…”

Comparative Morphological and Crystallographic Analysis of Electrochemically- and Chemically-Produced Silver Powder Particles

“…The shape of powder particles depends on both the conditions of electrolysis, such as the current density or overpotential, the type and composition of electrolyte, temperature, the type of working electrode, regime of electrolysis, etc., and the nature of metals [6]. Although powder particles are the most often dendritic shape, they can also be in the form of flakes, fibrous, spongy, wires at sub-micrometer or nanometer scale, cauliflower-like, as well as in the many other irregular forms [4][5][6][7][8][9][10][11][12][13][14][15][16]. Various forms of dendrites are formed by electrolysis, and the shape of dendritic particles is primarily determined by the type of metals [4,6,9,[11][12][13][14].…”

Morphology and Texture of Zinc Deposits Formed at the Edge of a Rotating Washer Electrode

“…Although it is known that edge roughness has a strong effect on the initiation time and propagation rate of dendrites ( Ref 7,8), no influence on the texture and morphology of dendrites was found in the evaluated range (not shown). Therefore, only the results for the samples G80 are presented in the following paragraphs.…”

“…Therefore, in order to understand how the process variables influence dendritic growth during electrogalvanization, the rotating washer electrode (RWE) was designed: an electrochemical cell that replicates the fluid dynamics and the current distribution on the sheet edge. Several operating parameters were studied with the RWE in previous works (Ref 7,8); these results showed that electrolyte flow and current density have a great influence on the kinetics of dendrite growth. Nevertheless, the aforementioned research was focused on the formation of dendrites and little attention was paid to their morphology and texture.…”