Formation of Salt Films during Anodic Metal Dissolution in the Presence of Fluid Flow

Anodic dissolution of a metal in the presence of flowing electrolytic solution was studied by both experimental and theoretical methods. A mathematical model was developed which included emphasis on the potential field distribution near the dissolving electrode, and on convective diffusion effects-in both laminar and turbulent flow. Critical conditions were identified for saturation, by dissolved metal salt, of the solution adjacent to the anodic surface. Theoretical results were compared to measurements obtained in a channel flow system of the critical flow velocities above which pure iron would not repassivate in 0.5M H2SO4.