Oxide-solution interface

A mechanism such as that given above provides explanations for the known effects of many process variables ". The reductive dissolution and undermining processes require access of the acid to the metal surface, hence the benefits obtained by the deliberate introduction of cracks in the oxide by cold-working prior to pickling. Also the increase in pickling rate with agitation or strip velocity can be explained in terms of the avoidance of acid depletion at the oxide-solution interface. 

The corrosion current due to diffusion of metal ions through the passivating film, and dissolution of metal ions at the oxide-solution interface. Clearly, the smaller this current, the more protective is the oxide layer. 

Westall, J. C. and H. Hohl, 1980, A comparison of electrostatic models for the oxide/solution interface. Advances in Colloid Interface Science 12, 265-294. 

Any charge change occurring only between the reference electrode and the semiconductor is a candidate for a change of Ids. In particular one of the most important points is the surface potential at the oxide-solution interface (surface potentials between the CIM and the solution and the potential between the SiC>2 and the CIM, in the presence of a given CIM. The ISFET operation may be represented by the following changes-flow which may be considered as superimposed on the quiescent point determined by the reference electrode potential ... 

Reactions at the Oxide-Solution Interface Chemical and Electrostatic Models... 

The nature of the problem in establishing a mechanistic model of the oxide-electrolyte interface, in which chemical and electrostatic energies are described explicitly, can be appreciated by consideration of the adsorption reaction depicted in Figure 2. The adsorption of a hydrogen ion from the bulk of a monovalent electrolyte is considered. The oxide-solution interface is divided conceptually into four regions the bulk oxide (not shown in the figure), the oxide surface at which the adsorption reaction takes place, the solution part of the double layer containing the counterions, and the bulk of solution. 

Many models, which could be classified as "surface complexation models (6-8)," have been used to describe reactions at the oxide-solution interface. Although there are differences in the way these models are formulated, they all have two features in common ... 

With regard to the assignment of ions to the mean planes in the interface, the oxide-solution interface can be compared to two ideal interfaces which are more thoroughly characterized the metal-solution interface and the silver iodide-solution interface. 

Free Energies of Electrical Double Layers at the Oxide-Solution Interface... 

The aim of this paper is not to add to the current debate but to present a simple graphical method of analysing the free energy of formation of the electrical double layer at the oxide/solution interface ( 1). This will provide a simple way of visualizing the complementary roles of chemical reactions or surface properties of... 

Although a family of OgS - Jig8 values are allowed under Equation 7 the actual equilibrium state of the oxide/solution interface will be determined by the dissociation of the surface groups and the properties of the electrolyte or the diffuse double layer near the surface. For surfaces that develop surface charges by different mechanisms such as for semiconductor, there will be an equation of state or charge-potential relationship that is analogous to Equation 7 which characterizes the electrical response of the surface. 

Using a simple amphoteric model for the mineral surface, we have demonstrated the role specific chemical binding reactions of potential determining Ions In determining the electrical properties and thermodynamics of the oxide/solution interfaces. A by-product of our study Is that under appropriate conditions, an amphoteric surface can show marked deviations from ideal Nernstlan behaviour. The graphical method also serves to Illustrate the... 

Returning to our introductory remarks about the existence of various models for the oxide/solution interface, It may be appropriate to point out that the results of very relevant experiments based on electrokinetic measurements are often not used in conjunction with titration data. Granted that there may be additional difficulties in identifying the precise location the slipping plane and hence the significance of the electrokinetic c potential may be open to debate, both titration and electrokinetic data ought to be combined where possible to elucidate the behaviour of the oxide/solution Interface. 

Adsorption-Desorption Kinetics at the Metal-Oxide-Solution Interface Studied by Relaxation Methods... 

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