| Themes > Science > Chemistry > Electrochemistry > Introduction to Electrochemical Techniques > Polarization of Reactions > Resistance Polarization |
Solutions of electrolytes generally have a rather poor conductivity compared to metals, particularly for dilute solutions. In corrosion systems this is often compounded by paints or other films of insulating materials which can only conduct by way of traces of water dissolved in the coating. As we have seen above, corrosion consists of two or more essentially independent reactions, and it is quite common for these to occur at different sites on the metal surface. If the solution has a high electrical resistance this will give rise to a potential difference between the anodic and cathodic sites, which is known as resistance polarization. If resistance polarization dominates a reaction, it is referred as resistance or IR controlled (the latter term arises from Ohm's Law, V = IR). |
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