1971/10/01 by Florian Mansfeld, F. Mansfeld
Engineering · Materials Science · #Concrete Corrosion and Durability #Corrosion Behavior and Inhibition #High voltage insulation and dielectric phenomena
paper · doi:10.5006/0010-9312-27.10.436
crossref issued 1971/10/01 · crossref published 1971/10/01 · crossref published-print 1971/10/01 · openalex publication_date 1971/10/01 · crossref created 2013/02/11 · crossref deposited 2025/03/18 · openalex created_date 2025/10/10 · crossref indexed 2026/07/27 · openalex updated_date 2026/07/28
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 anode is shown to be proportional to the area ratio (AC/AA) of anode and cathode for higher values of AC/AA. This is the so-called catchment principle.