Electrochemical Behavior of Carbon Steels Under Thickness-controlled Solution Layer

Abstract

The effect of solution layer thickness on the atmospheric corrosion of carbon steel was investigated using novel devices fabricated by a 3D printer. These novel devices allowed us to control the solution layer thickness precisely. Potentiodynamic polarization measurements were performed under thickness-controlled solution layer, and oxygen diffusion limiting current density（j_lim） and anodic current density（j_anode） were measured. As the solution layer becomes thinner, j_lim increased and j_anode decreased. This result indicates that corrosion accelerates when the solution layer becomes thinner. The diffusion coefficient of oxygen was calculated as 3.20×10^－5 cm² s^－1 from the relationship between j_lim and solution layer thickness, and the critical diffusion thickness was estimated to be 0.87 mm.