Numerical Simulation On One-dimensional Galvanic Corrosion System Based On Equivalent Circuit Model

Galvanic corrosion which causes great destruction on economic development and production safety generally exists in ail kinds of national economic construction fields. The corrosion of each position is not uniform because of the influence of the external factors, it’s difficult to obtain ideal result for the estimation of corrosion. A great deal of work has been done to simulate the corrosion of cathodic and anodal metal. The project adopts equivalent circuit model to calculate potential distribution in one-dimensional galvanic corrosion system.Piecewise linear fitting method is maken use to process polarization curve for nonlinear boundary conditions in equivalent circuit model. The research shows the experimental data of piecewise linear fitting method more accords with that of actual measurement and the better polarization curve fitted, the higher accuracy of the result is. In addition, the applicability of equivalent circuit model is researched in one-dimensional galvanic corrosion system such as oxygen diffusion controlled system and active corrosion system. In these two systems the theoretical potential distribution accords with practical poential distribution, even in different electrolyte concentration of oxygen diffusion controlled system, which shows equivalent circuit model is applicative in these two systems.Galvanic corrosion is influenced by external and own factors, so the project researches with electrolyte concentration, galvanic series and area ratio of cathode and anode. Potential distribution is simultaneously influenced by solution resistivity and metal polarization curve in different electrolyte concentration solution. Conductivity is the main influencing factor in low resistivity of electrolyte solution while polarization curve plays the main role in high resistivity of electrolyte solution. Potential distribution of different galvanic series is closely related to polarization resistivity. The higher the polarization resistivity is, the steadier the data of potential distribution is. The change of cathodic area is different from the change of anodic area on potential distribution in galvanic corrosion system. The potential of system shifts toward the positive direction when cathodic area largens, the potential shifts toward the negative direction when anodic area minishes up to a particular value. At the particular value potential tends to steady value.