Ion Permselectivity of Artificially Synthesized Zinc Corrosion Product Films

摘要

Zinc hydroxychloride (Zn_5(OH)_8Cl_2-H_2O) is well-known as a typical corrosion product of zinc coated steel sheets. It has barrier effects on permeation of corrosion factor. It has not been cleared that what kinds of properties of zinc hydroxychloride, such as ion permselectivity or electrical resistance are involved in control barrier effects. But it is capable of evaluating zinc hydroxychloride's transport number of chloride ion, so we can define the amount of chloride ion that passing through corrosion product. In this paper, in order to evaluate the transport number of chloride ion, we prepared the film that contained zinc hydroxychloride and measured its membrane potential in potassium chloride solution. As the result of membrane potential measurement, we found that the ion permselectivity of the film was anionic. Also, its transport number of chloride ion was 0.58, smaller than that of iron (K) oxide.