Nebojša D. Nikolić

Formation of two-dimensional (2D) lead dendrites by application of different regimes of electrolysis

Electrodeposition of lead from nitrate electrolyte in constant regimes of electrolysis was analyzed and the obtained powder lead deposits were examined by scanning electron microscopy. Polarization curve for lead electrodeposition consisted of two parts separated by an inflection point. The first part of the polarization curve was characterized by a linear dependence of the current density on overpotential. The linear part of the polarization curve corresponded to ohmic-controlled electrodeposition and single lead crystals were formed in this range of overpotentials. A rapid increase in the current density with increasing overpotential was observed after the inflection point (the second part of the polarization curve). Two-dimensional dendrites were the dominant morphological forms obtained at overpotentials and current densities belonging to the second part of the polarization curve, indicating that the rapid increase of the current density with increasing overpotential corresponded to activation controlled electrodeposition at the tips of the formed dendrites. Comparing the morphologies of the obtained lead deposits with those belonging to the same group of metals (metals characterized by a high exchange current density), such as silver, cadmium, and tin, a strong dependence between the nucleation type and the shape of dendrites for the metals belonging to the same group was established.

Hydrogen Co-deposition Effects on the Structure of Electrodeposited Copper

The creation of open porous structures with an extremely high surface area is of great technological significance because such structures are ideally suited for electrodes in many electrochemical devices, such as fuel cells, batteries, and chemical sensors. The open porous structure enables the fast transport of gases and liquids, while the extremely high surface area is desirable for the evaluation of electrochemical reactions. The electrodeposition technique is very suitable for the preparation of such structures because it is possible to control the number, distribution, and pore size in these structures by the choice of appropriate electrolysis parameters.

Structural characteristics of bright copper surfaces

In this work, the structures of copper surfaces polished mechanically and polished both mechanically and electrochemically, as well as copper coatings obtained in the presence of basic and top brightening addition agents were examined and compared with the structure of a silver mirror. It was shown by the STM technique that the structural characteristics important for the mirror brightness of the copper surface polished both mechanically and electrochemically and the copper coating are: (1) flat and mutually parallel parts of the surface which are smooth on the atomic level and (2) distances between adjacent flat parts are comparative with the distances between the adjacent flat parts of a silver mirror. Also, on the basis of the STM analysis, a mathematical model treating brightness from the point of view of geometrical optics was developed. X-ray diffraction analysis of the copper surfaces showed that mirror brightness is not associated directly with the degree of preferred orientation.

General Theory of Disperse Metal Electrodeposits Formation

The most frequently used form of the cathodic polarization curve equation for flat or large spherical electrode of massive metal is given by

Morphology of Electrochemically and Chemically Deposited Metals

j = \frac{{{j_0}({f_{\rm{c}}} - {f_{\rm{a}}})}}{{{1} + \frac{{{j_{{0}}}{f_{\rm{c}}}}}{{{j_{\rm{L}}}}}}},

The Effect of Morphology of Activated Electrodes on Their Electrochemical Activity

The effect of magnetic fields applied on magnetic metals electrodeposition was examined. Nickel deposits obtained from a Watt solution with coumarin, at cathodic potentials of - 1000, -1200, and -1300 mV/SCE, without and with. both, perpendicular and parallel oriented to the electrode surface low applied magnetic fields (up to 500 Oe) were examined by scanning electron microscopy (SEM) technique. At a potential of - 1300 mV/SCE, a dramatic difference was observed between nickel morphologies obtained with a perpendicular oriented magnetic field (zero MHD effect) and those obtained in the absence of one. The nickel deposit obtained with perpendicular oriented magnetic fields was a very developed 3D arboreous-bead-dendritic structure. On the other hand, the nickel deposit obtained without the presence of magnetic field was very rough, with a clearly visible clustered structure. The obtained nickel morphologies are then compared with copper morphologies. Based on the fact that copper deposits obtained with and without a perpendicular oriented magnetic field were dendritic structures, the observed difference between nickel deposits with and those without a perpendicular oriented field, is essentially ascribed to the magnetoresistance effect on the magnetic deposits, which are nonexistent in nonmagnetic materials. We also have done experiments with iron deposits.

An electrochemical illustration of the mathematical modelling of chlorine impact and acidification in electrochemical tumour treatment and its application on an agar–agar gel system

This book describes the newest achievements in the area of electrochemically and chemically deposited metals and alloys. In particular, the book is devoted to the surface morphology of deposited metals and alloys. It contains an in-depth analysis of the influence of the parameters of electrodeposition or chemical deposition of metals and alloys, which will likely lead to technological advances in industrial settings world-wide. Professionals in electrometallurgical and electroplating plants will find the book indispensable. This book will also be useful in the automotive, aerospace, electronics, energy device and biomedical industries. In academia, researchers in electrodeposition at both undergraduate and graduate levels will find this book a very valuable resource for their courses and projects