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Abstract  The electrodeposition process of Co films in a sulfuric acid solution was examined in a magnetic field (0–5 T). The surface morphology of Co films electrodeposited without a magnetic field was drastically modified with the variation of hydrogen gas evolution rate. Crystalline α-Co was formed in the range of pH = 1.5–6.0, while β-Co was not observed. When the magnetic field was superimposed perpendicular to the electric field in the acidic solution (pH = 1.5), the hydrogen evolution rate was promoted by MHD convection, which enhanced the ionic mass transfer (H+ and Co2+) near the electrode surface. Moreover, crystalline β-Co was formed simultaneously with the appearance of the elongated ridge-shape precipitates under a higher magnetic field (≥3 T). [ABSTRACT FROM AUTHOR]

Scanning Kelvin probe and electrochemical impedance spectroscopy were used to study the release behaviour of inhibitor anions doped in polypyrrole film (e.g. molybdate, 3-nitro salicylate). The polypyrrole coatings were formed on mild steel and zinc substrates in aqueous solution. It was shown that the release behaviour of the molybdate and 3-nitro salicylate anions depends on the size of cations in the electrolyte. The delamination is determined with the migration and incorporation of small cations. [ABSTRACT FROM AUTHOR]

The Markov chain model of alloy deposition was applied to cobalt–nickel. The characteristic parameters of the model are the gi values describing the selectivity of the deposition process for its components. The values recently determined for Co and Ni (gCo and gNi) depend on the current density. This could be quantitatively described by the mass transport limitation for Co. The model was also applied to the nickel–molybdenum system, an example for induced co-deposition. Data published by Podlaha and Landolt [4, 5] could be described by the equation [ABSTRACT FROM AUTHOR]

Summary Two new thiophene derivatives bearing redox active p-nitrophenyl units were synthesized and electropolymerized to conducting polymers. It is found that not only the structure of monomer, but also the employed polymerization conditions have considerable effect on the electroactivity of the bonded redox groups of resulting polymer films. Depending on used conditions such as polymerization time, the polymerization of the same monomer could result in a polymer with well-defined redox transition of the nitrophenyl group or a polymer, in which the redox group is completely electrochemical inaccessible. Using designed experiments, we explained this phenomenon. These investigations provide further knowledge about the behaviors of redox group attached to electrode surface. [ABSTRACT FROM AUTHOR]

The protection mechanism of intrinsically conducting polymers (ICPs) is still under discussion. Most of the discussions concentrate on the effect of the redox behavior and electroactivity of ICPs on the corrosion protection. In the present paper it is shown that polymethylthiophene (PMT) films electropolymerized on mild steel, with 2-(3-thienyl)ethylphosphonic acid used as adhesion promoter, show the desired redox activity. The interaction between the PMT film and some conventional coatings, and the influence of the pH of electrolyte, were investigated. It was shown that the electroactivity of PMT film is lost by the interaction with coatings of high nucleophilicity and is markedly decreased by immersion in an aqueous solution of pH 11. [ABSTRACT FROM AUTHOR]