Anodic dissolution formalism

The electrodeposition of nickel, Ni, has been studied in acidic ionic liquids [37, 38, 45 8]. A divalent nickel species, Ni(ll), can be introduced into the ionic liquids by dissolving nickel dichloride, NiCla, or the anodic dissolution of Ni metal. The reduction of Ni(ll) occurs at around 0.38 V, producing metallic nickel in the acidic EMICI-AICI3 ionic liquid [47]. The formal potential of Ni(ll)/Ni in an acidic BPCI-AICI3 ionic liquid is reported as 0.800 V on the mole fraction scale [46], The electrodeposition of Al-Ni alloys occurs at the potential more negative than the... 

EMICl- [22, 37, 38, 51-54], and BMICI-AICI3 [55] ionic liquids. In the case of acidic ionic liquids, it is possible to introduce monovalent and divalent copper species, Cu(l) and Cu(II), by dissolving copper chloride and dichloride, respectively, and by the anodic dissolution of metallic copper. Metallic Cu can be obtained by the reduction of Cu(I). The formal potentials of Cu(I)/Cu in an acidic MPCl-BPC1-, EMICI-AICI3 are reported as 0.777 [49], 0.784 [50], and 0.837 [52] V, respectively. Cu(I) can be also obtained by the reduction of Cu(II), of which the formal potentials in the acidic MPCl- and BPCI-AICI3 are reported as 1.851... 

It is worth noting that, in whatever way a pit nucleus was bom, its further development to form a pit embryo (growing metastable pit) depends on the electrolyte concentration which locally sets up in the electrolyte when the metal dissolves. The development of the pit embryo implies the local stabilization of an acidic corrosive medium, differing from the surrounding one. This local acidification induces a local dissolution of the metal in the active state, which is compensated only by the diffusion of the corrosion products. This dissolution in turn provokes an acidification due to the hydrolysis reactions and the process is self-sustained, provided that fire diffusion or the electromigration is slow enough in the electrolyte. Formally [3h,5d], if Jis the anodic current andXrepresents the concentration in corrosion products, one has dX/dt = KJ V, X) - DX, where the metal-electrolyte potential difference F is a control parameter (J increases with V) and parameters K and D represent respectively the production in corrosion products by the anodic dissolution and their dilution into the electrolyte by a diffusion process. The steady state conditions write dX/dt = 0. The system is locally stable when... 

Johnson and Mackenzie reported the formal potential of the couple W /W in this eutectic. The species was produced by anodic dissolution of a tungsten electrode in the presence of Yb + (reducing agent). Attempts to directly generate tungsten ions in the melt were unsuccessful instead chlorine evolution was observed. The passivity was attributed to the adherent film of the insoluble polymeric chlorides formed by anodic polarization. 

Alloy dissolution — The process of anodic oxidation of an alloy electrode by application of a suitable - electrode potential. It leads to dissolved products. Under non-electrochemical conditions the dissolution of an alloy can be performed with a chemical oxidant The rate of dissolution depends on the structure and homogeneity of the processed material. When the applied potential or, in the case of chemical dissolution, the oxidation potential of the chemical oxidant lays between the formal potentials of the dissolved components, a selective... 

Anodic-stripping voltammetry (ASV) is used for the analysis of cations in solution, particularly to determine trace heavy metals. It involves pre-concentrating the metals at the electrode surface by reducing the dissolved metal species in the sample to the zero oxidation state, where they tend to form amalgams with Hg. Subsequently, the potential is swept anodically resulting in the dissolution of the metal species back into solution at their respective formal potential values. The determination step often utilizes a square-wave scan (SWASV), since it increases the rapidity of the analysis, avoiding interference from oxygen in solution, and improves the sensitivity. This technique has been shown to enable the simultaneous determination of four to six trace metals at concentrations down to fractional parts per billion and has found widespread use in seawater analysis. 

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