Anodic dissolution model

The strange anodic polarization behaviors (negative difference effect, lower apparent valence, low anodic dissolution efficiency, low anodic polarization resistance and poor passivity ) are closely associated with the AHE process which is further related to the onset of localized corrosion or pitting . A comprehensive anodic dissolution model can be employed to understand these. 

According to the comprehensive anodic dissolution model, the further anodic reaction (1.32) is a potential-dependent electrochemical process which can become faster at a more positive polarization potential. This means that y will increase and therefore n should also increase as the potential becomes more positive. This prediction has been experimentally verified n starting at 1.2 approached a value of 1.8 after the anodic polarization potential was more positive than -1 V/NHE (Perrault, 1978). Because the hydrogen production reactions in the anodic process cannot fully stop at anodic potentials, n cannot reach its theoretical value of 2, which is also consistent with experimental observation (Perrault, 1978). 

Fig. 13.23 Schematic of crack penetration with time in the film-rupture/anodic-dissolution model [29]...

In [52], a modeling of periodic and chaotic dynamics in anodic dissolution... 

Partial blocking effect was first identified for pure iron in contact with aerated sulphuric acid medium [55]. Corrosion of carbon steel in sodium chloride media clearly showed the porous layer effect (see Section 5.2) [74]. The same effect was found for zinc corrosion in sodium sulphate [75] and the properties of the layer which was demonstrated to be formed of an oxide/hydroxide mixture were further used for building a general kinetic model of anodic dissolution [76], usable for measurement of the corrosion rate from impedance data. 

In contrast to N,N-dimethylethanolamine, the interaction in z -BuOH without electrolysis of the reaction mixture does not produce Pc. This fact could be used successfully to electrosynthesize various metal phthalocyanines, synchronizing the Pc formation on the cathode and metal anode dissolution. This could prevent the formation of mixtures of metal-free and metal phthalocyanines [33]. As will be shown below, N,N-dimethyletanolamine could also be used successfully as a model solvent, in whose medium the formation of the metal-free Pc takes place even at room temperature under conditions of UV irradiation (see Table 5.5). 

Williams has simplified the real activities in mitochondria and made the model look like an H2-02 fuel cell. On the right (i.e., at certain sites in the mitochondrion) there is an anodic dissolution of H2, which injects electrons into the mitochondrion. At the other side, at different types of sites in the mitochondrion, 02 is reduced by... 

A quantitative description of the diverse morphological features of PS requires the integration of the aspects discussed above as well as the fundamental reaction processes involved in silicon/electrolyte interface structure, anodic dissolution, and anodic oxide formation and dissolution as detailed in Chapters 2-5. Any mathematical formulation for the mechanisms of PS formation without such a global integration would be limited in the scope of its validity and in the power to explain details. In addition, a globally and microscopically accurate model would also require the full characterization of all of the morphological features of PS in relation to all of the... 

Logan [42] suggested a film rupture or sHp-step dissolution model for SCC mechanism where the crack is initiated by locahzed anodic dissolution. This mechanism postulates that plastic strain in the metal at the crack tip causes a fracture of the oxide barrier film. The film rupture model (FRM) assumes a repetitive, cycling process of film rupture, dissolution of the underlying metal, and repassivation. 

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