When there are two partial process in a mixed potential system and both are under activation control, the most probable forms of the current densities of the anodic and cathodic partial processes are Equations 33 and 35, respectively. For an isolated metal, the overpotential (since the corrosion potential represents the perturbed electrode potential in this case) is [Pg.59]

Fig. 11. Schematic representation of an equivalent circuit for a mixed potential system. Q double layer capacitance, R i solution resistance, R anodic charge transfer resistance, R cathodic charge transfer resistance. |

Since Equation 58 is identical in form to Equation 30, the analysis of data for mixed potential systems is the same as that for simple electrode reactions. [Pg.61]

Just as the Butler-Vohner equation was shown to be linear near E " with a slope inversely proportional to j o (low-field approximation. Sect. 1.3.8), the net current in a mixed potential system, represented by Eq. (41), is Knear near corr. with a slope inversely proportional to icorr-Since polarization resistance measurements are made near the corrosion potential, the net currents are often low. Therefore, errors associated with ohmic potential drop are usually small. However, there are cases for which ohmic potential drop creates significant error in the Rp measurement. The measured R is the sum of the trae polarization resistance. [Pg.48]

It was considered that hydrogen peroxide is formed at silver and chalcocite surfaces when oxygen is present as this compound is an intermediate in the cathodic reduction of oxygen. Clearly, then, there is interaction between the two reactions that make up the mixed potential system, namely, xanthate oxidation and oxygen reduction. Thus, care must be taken in considering the individual processes in isolation. [Pg.422]

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