Electrodeposition experimental investigations

Simple experimental conditions for an investigation of the relation (5.28) can be obtained in the case of electrodeposition of silver on silver single crystal faces prepared by the capillary technique [5.29, 5.74, 5.75]. As already shown, such crystal faces are usually intersected by only a few single screw dislocations which produce growth pyramids or cones with an uniform slope (cf. Fig. 5.31). The parabolic dependence (5.28) has been experimentally found in the systems standard AgQtkl)/... 

These are fundamental considerations and are of interest not just to electrochemists and sonochemists, but care must be taken in correctly attributing an apparent shift in an experimentally observed potential under ultrasound. As already mentioned, system parameters and other factors may influence an observation beyond the effect under investigation. Thus there have been reports on the use of the titanium tip of the sonic horn itself, suitably electrically insulated, as the electrode material [50]. Dubbed the sonotrode , this is a clever idea to combine the two active components of a sonoelectrochemical system the authors noted the expected enhancements in limiting currents and an alteration in the morphology of copper electrodeposited from aqueous solution on to the titanium tip, which was the reaction under test. However, although titanium is widely used in sonochemistry because of its low-loss characteristics under vibration, it is not a common electrode material for electroanalysis because of its inferior electron transfer characteristics... 

Previous real-time studies of ramified electrodeposited formations were performed in two-dimensional cells due to the depth of focus problem while using optical microscopy. The role of hydrogen bubbles could not be investigated in detail since the bubbles in two-dimensional electrodeposition cells markedly retard the development of ramified electrodeposits. On the contrary, our experimental approach enabled us to monitor hydrogen bubble evolution and the related Zn deposit morphological changes in 3D and with no restrictions on the electrodeposition geometry. 

Heterojunctions formed by electrodepositing polypyrrole or polyaniline on retype silicon were studied with PVS [756]. Experimental observations were explained invoking photosensitization by electrochemically generated polarons in the polymer film. The effects of nano-sized particles of Fe203 that were incorporated into films of polypyrrole were investigated with PVS [757]. 

The first subdiscipline of chemistry in which the QCM was widely applied was electrochemistry. In 1992 Buttry and Ward published a review entitled Measurement of interfacial processes at electrode surfaces with the electrochemical quartz crystal microbalance , with 133 references [8]. This is the most widely cited paper on quartz crystal microbalances. After presenting the basic principles of AT-cut quartz resonators, the authors discuss the experimental aspects and relation of electrochemical parameters to QCM frequency changes. In their review of the investigation of thin films, they discuss electrodeposition of metals, dissolution of metal films, electrovalency measurements of anion adsorption, hydrogen absorption in metal films, bubble formation, and self-assembled monolayers. The review concludes with a brief section on redox and conducting polymer films. 

Such electrodeposition process had been widely investigated for electroreduction of germanium species in molten KF-NaF-K2GeF6-Ge02 electrolyte [8]. One of the most interesting information has been obtained with the automatic balance experimental technique permitting to record the weight of the electrode in situ in course of the electrolysis [9]. 

There are only a few studies on the electrochemical behaviour of rhenium in molten salts [1-6]. Most investigations dealt with electrodeposition of rhenium and its alloys. The absence of reliable data on the electrochemical reduction of rhenium in molten salts greatly impedes further progress in the field of rhenium galvanoplastics and hinders interpretation of the experimental results. 

The production of metallic powders through hydrometallurgical or electrodeposition routes has extensively been studied over the last century. The formation of metallic powders during electroless deposition of films of metals or alloys is observed when the so-called bath instability takes place [1, 16, 17]. As such, the electroless deposition was far less investigated than its electrolytic counterpart. The bath instability is usually seen in the experimental conditions at elevated temperatures or when the concentration of the reducing agent is too high. 

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