Numerical Analysis for Corrosion near Shear Cut Edge of Galvanic Steel Sheet

Abstract

We have developed a new mathematical model for galvanic corrosion with ions movement, reactions and electroneutrality. In this model, ion density distribution is corrected by solving Poisson's equation to satisfy electroneutrality. Major ion species and reactions are considered in NaCl solution, MgCl₂ solution and artificial sea water on a Fe/Zn galvanic couple.
Distribution of corrosion products in NaCl solution and MgCl₂ solution obtained by numerical analysis agreed well with measured by FTIR method qualitatively.
Corrosion progresses at shear cut edge of galvanic steel sheet in NaCl solution, MgCl₂ solution and artificial sea water were simulated and discussed. In addition, galvanic corrosion under a paint film near the shear cut edge was computed. The numerical analysis result indicated that concentration of Cl⁻ under the paint film was increased by more than factor of 10.