Area Relationships in Galvanic Corrosion

Publisher Website
Google Scholar
Abstract
The effect of variations of the area of two metals in a galvanic couple is discussed for three common cases. In Case 1, it is assumed that the only significant process on the more active metal (A) at the galvanic potential (ϕg) is metal oxidation (dissolution), while the only significant process on the more noble metal (C) is reduction of the oxidizer (H+, H2O, O2) and Tafel behavior is observed. Various possibilities to present the galvanic current as a function of electrode areas, which might have lead to some confusion in the literature, are discussed. In Case 2, it is assumed that metal (A), the anode in the galvanic couple, is polarized only slightly from its corrosion potential. It is shown that in this case the galvanic current density (igA) is not equal to the dissolution rate (idA) of the anode. A correlation between these two values is given. In Case 3, it is assumed that the cathodic process on both metals is entirely diffusion controlled. In this case, the dissolution rate of the anod...

This publication has 0 references indexed in Scilit: