Recently a Markov chain model has been proposed to predict the composition of alloys as a function of the electrolyte composition. The essential parameters of this model are selectivity constants, describing the selectivity of the growth centers, the kink site positions, for the ions of the metal components in the electrolyte.In this paper application of the simple model to deposition of intermetallic compounds will be discussed. The Markov chain model can be successfully applied to the formation of the intermetallic compound NiSn. Whereas the model can describe well the deposition of Ni rich Zn-Ni alloys at low current densities, it fails at high current densities with anomalous alloy composition.

Deposition of amorphous chromium-carbon layers is possible from a trivalent chromium electrolyte containing 0.6 mol/l formic acid. The formation of chromium/formic acid complexes inhibits the aging of the electrolyte and the oligomerization. Deposition of a 15–20 μm thick chromium film is possible with DC condition. Thicker films can be deposited with pulse plating using reversed pulse sequences and pulse lengths in the millisecond region. The optimized conditions concerning pulse current densities and pulse times were determined and the composition and morphology of the films investigated.

The search for effective additives is important for the development of new metal deposition processes. The hard/soft concept is a possible way for the selection of suitable substances.Hardness or softness are connected with molecular properties like electronegativity or the chemical potential of electrons. The density functional theory (DFT) provides methods for calculating the respective values. Corresponding function of the side of the electrode is the Fermi energy, the upper level of occupied electron energy levels. Hardness and softness of the electrode depend on the electrode potential. This dependence will be discussed.

Abstract not Available.

Abstract not Available.

The relation between layer properties and structure of the deposit is of permanent importance in the development of electrocrystallization. The continuous question is the influence of the experimental conditions on the structure and with this bridge on the properties of electrodeposits. A very important step in electrodeposition is nucleation. Some recent developments of nucleation will be discussed. An important factor to influence nucleation and growths are additives. Adsorption of additives is still described by the thermodynamic approach of adsorption isotherms. But a new impetus might provide the transfer of Pearson's hard–soft concept to adsorption on electrified interfaces. An important step is the correlation of hardness and softness with the chemical potential of electrons and the dependence of the chemical potential on the electrode potential. A further new step is the application of distributed field calculations to calculate chemical potentials of electrons. An outlook into further developments is given at the end of the article.

The electrochemical processes on a growing metal layer can be described as a chain of processes consisting of nucleation and formation of a stable grain, growth of the active grain, and death of the active grain. Considering the statistical nature of the process chain, mean growth rate, mean lifetime, mean death rate, mean density and mean size of the active grains can be defined. Equations for the rate of nucleation are given in the literature. Stationary growth of the metal film is achieved if the rate of nucleation is equal to the death rate of active grains. From the condition of stationary growth an equation for the dependence of the average grain size on the experimental parameters can be derived. Several situations of metal deposition with different process parameters are discussed and compared with experimental results.

This book introduces the principles of electrochemistry with a special emphasis on materials science. This book is clearly organized around the main topic areas comprising electrolytes, electrodes, development of the potential differences in combining electrolytes with electrodes, the electrochemical double layer, mass transport, and charge transfer, making the subject matter more accessible. In the second part, several important areas for materials science are described in more detail. These chapters bridge the gap between the introductory textbooks and the more specialized literature. They feature the electrodeposition of metals and alloys, electrochemistry of oxides and semiconductors, intrinsically conducting polymers, and aspects of nanotechnology with an emphasis on the codeposition of nanoparticles.This book provides a good introduction into electrochemistry for the graduate student. For the research student as well as for the advanced reader there is sufficient information on the basic problems in special chapters. The book is suitable for students and researchers in chemistry, physics, engineering, as well as materials science. It includes: introduction into electrochemistry; metal and alloy electrodeposition; oxides and semiconductors, corrosion; intrinsically conducting polymers; and, codeposition of nanoparticles, multilayers.

This chapter discusses some aspects of the chemical deposition of metals. Organic solvents provide suitable potential windows for some important metals such as aluminum and lithium that cannot be deposited from aqueous electrolyte. Some metals are deposited from molten salts. The so-called room temperature molten salts or ionic liquids are a further group of solvents used to deposit metals like aluminum again that cannot be deposited from aqueous electrolytes. In electrochemical phase formation, nucleation must be on a surface of a foreign or native substrate. If the nucleus formed on a surface is a cluster that grows in all three dimensions, one speaks of a three-dimensional nucleation. The nucleus is a cluster of only a few atoms and can be depicted as a semi-sphere. In the process of deposition of metal ions into a crystalline phase an atom has to pass several intermediate positions. In the model, the main three surface processes are shown, which are the charge transfer process, surface diffusion, and the transfer from the ad-atom position into a step or kink position. Not shown are the diffusion processes in the electrolyte. Each step can be rate determining such as the charge transfer between electrolyte and metal surface, surface diffusion, or the transfer into a step or kink position, the final crystallization process. Many metals are made by electrodeposition. Several metals are prepared by electrolysis in molten salts. A variety of plating processes have been developed for the metals deposited by electroplating. Quite different, usually aqueous, electrolytes are used. Each electrolyte has characteristic features and produces deposits with quite different properties.

This chapter describes electrochemical properties of materials with covalent bonds and stoichiometric composition. Many of these materials are semiconductors. A characteristic feature of semiconductors is the separation of the electron energy levels into two bands, the valence band with occupied energy levels and the conduction band with unoccupied energy levels. Both bands are separated by an energy gap. The band gap energy, Eg, determines the intrinsic conductivity because electricity can only be transported through the semiconductor if some electrons are excited from the valence band to the conduction band. Then either holes in the valence band or electrons in the conduction band become mobile. In electrochemistry the semiconductor (phase I) is connected to an electrolyte (phase II). In equilibrium, the electrochemical potential for the electrons in both phases must be equal. The electrochemical potential of the electrons in the semiconductor is equal to the Fermi energy. Transfer of the charge between both phases establishes the equilibrium condition. For an n-semiconductor with excess electrons, electrons move from the conduction band to the electrolyte and a positive charge is built up in the space-charge region of the semiconductor. This leads to the build up of a positive Galvani potential difference between semiconductor and electrolyte. Another characteristic electrochemical property of a semiconductor/electrolyte contact is the double-layer capacitance, which is an approximation of the space-charge capacitance. The space-charge capacitance can be determined by impedance measurements. If there are no current flows in the depletion region, the impedance is given by the reciprocal value of the space-charge capacitance.