Electrochemical interactions

An electrochemical interaction of two or more materials (materials 1 and 2 in Fig. 16.1) having a sufficiently distinct galvanic potential difference... 

The studies by Biermann et al. [28] indicate that the carbon blacks used as the conductive matrix in Leclanche cells remain chemically inert, that is, they do not undergo oxidation during storage or discharge of the cell. However, Caudle et al. [29] found evidence that the ion-exchange properties of carbon black, which exist because of the presence of surface redox groups, are responsible for electrochemical interactions with Mn02. The extent of MnO, reduction to MnOOH depends on the carbon black (i.e., furnace black > acetylene black). 

The electrochemical behavior was not ideal for the presumed cyanine-cyanine hybrid, probably due to the less effective electrochemical interaction among the positive charges. This should be attributable to the disadvantage of conjugation of the positively charged units by the central benzene ring. 

When a complex sulphide ore is subjected to wet grinding, electrochemical interactions between the grinding media and various sulphide minerals and chemical or electrochemical interactions involving dissolved species and mineral... 

Pulp potential in grinding process, is controlled by many factors, such as oxygen dissolved in pulp, oxidation of iron fine powders fi om the grinding media and particles of sulphide minerals, whose electrochemical interactions are very complex in the grinding-flotation system of sulphide minerals ore (Nakazawa and Iwasaki, 1985). 

Yelloji Rao M. K. and Natarajan, K. A., 1988. Influence of galvanic interaction between chalcopyrite and some metallic materials on flotation. Minerals Engineering, 1(4) 281 - 294 Yelloji Rao M. K. and Natarajan, K. A., 1989a. Effect of electrochemical interactions among sulphide minerals and grinding medium on chalcopyrite flotation. Minerals Metallurgical Processing, 6(3) 146- 151... 

Anions are nominally too large to be injected down channels in the semiconductor. However, under strong anodic bias there may be electrochemical interactions of the anions with the semiconductor surface (possibly by an ion exchange mechanism). 

A probable success could be theoretically reached using weak metals, such as Sb or Mg, in the chemical or electrochemical interaction with the Pc precursors. Undoubtedly, this method should be developed, since it is a possible route to prepare metal-free Pc after removing metal from the macrocycle. 

Simple reference electrodes, like a piece of metal, provide a reference potential that is produced by the electrochemical interaction between the metal and the chemical environment. If the concentration of the species taking part in this interaction changes, the potential of the metal will change. A change in the chemical composition of the environment can cause severe drift in the potential. 

Abdul-Raman, A., Amoroso, A.A., Branston, T.N., Das, A., Mahler, J.P., McCleverty, J.A., Ward, M.D. and Wlodarczyk, A. (1997) Dinuclear molybdenum complexes derived from diphenols Electrochemical interactions and reduced species. Polyhedron, 16, 4353-62. 

Partial pressure (10-1000 psi) Activity, effective partial pressure Activity, concentration Ion concentration, voltage Electrochemical interactions Biospecific interactions... 

There are two types of electrochemical interactions with bacteria bactericidal and fuel-cell related. 

Describe a potential electrochemical interaction between MnOz and Fe2+. Explain why the interaction is environmentally important. 

Figure 4.43 Titanium polish rate in I vol% NH4 OH sluiry as a function of Cu(NOj)2 concentration. The increase in polish rate is due to an electrochemical interaction of the titanium metal with copper ions in the slurry solution. (12S mm wafers polished on Strasbaugh 6CU polisher with 2.S wt% alumina hbrasive, 15 kPA, and 130 cm/sec.)...

Figure 4.49 Profilometer trace showing dishing of the titanium liner relative to the adjacent recessed copper metal. An electrochemical interaction between the copper metal and the titanium accelerates the normally low polish rate of titanium to produce the negative dishing.

Electrochemical interaction between the oxidizer and the metal is believed to play a key role in material removal in tungsten CMP. In this study, we use X-ray Photoelectron Spectroscopy (XPS) in conjunction with electrochemical measurements in both in-situ polishing conditions as well as in static solutions, to identify the passivation and dissolution modes of tungsten. Dissolution of tungsten oxides was found to be the primary non-mechanical tungsten removal mechanism in CMP. 

There are a number of electrochemical interactions which may be useful as the basis for detection in HPLC the most commonly used electrochemical detectors are based on amperometric measurements. The principle of operation of an amperometric detector is the oxidation or reduction of analyte in a flow-through electrolysis cell with a constant applied electrical potential, e.g. the oxidation of hydroquinone. 

Selective leaching is the process whereby a specific element is removed from an alloy because of an electrochemical interaction with the environment. Dezinci-fication of brass alloys is the most familiar example of this type of corrosion. It occurs most commonly when there is exposure to soft waters and can be accelerated by high carbon dioxide concentrations and the presence of chloride ions. 

The particle-size dependence of electrochemical interactions is a potentially very important, but largely unstudied, aspect of geochemically-significant mineral reactivity. 

Where might this be important As discussed above, biological activity can result in the simultaneous precipitation of mixtures of nanoscale sulfide minerals under certain conditions. Each mineral will exhibit a particular particle size distribution, dependent on the solution composition, bacterial activity, rate of crystal growth, and the nature of electrochemical interactions between the particles. These electrochemical reactions could lead to oxidation of one type of nanophase sulfide mineral of a certain size, and reduction of another type of nanophase sulfide particle or other species in the solution. In this way, a tremendous number of mineral-solution-mineral galvanic cells could develop, with potentially significant impact on dissolution kinetics, growth kinetics, and the mixture of phases observed. In addition to environmental relevance, these processes may shape the mineralogy of low-temperature ore deposits. 

Lorenzen, L. van Deventer, J.S.J. (1992a). Electrochemical interactions between gold and its associated minerals during cyanidation. Hydrometallurgy, 30, 177-194. doi 10.1016/0892-6875(92)90173-7... 

Electrochemical transductors transform the effect of the electrochemical interaction between an analyte and the electrode into a primary signal. Such effects may be stimulated electrically or may result from a spontaneous interaction at the zero-current condition. The following subgroups may be distinguished ... 

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