Electrochemical characteristic of cathodically protected mild steel in 3.5% Nacl and 1 M H2SO4

Abstract

The study focused on the electrochemical behaviour of mild steel in 3.5% NaCl and 1 M H2SO4 solutions using impressed current from external source. Open circuit potential, potentiodynamic polarization and chronoamperometry test methods were used to assess the corrosion performance of the mild steel in the solutions at room temperature (±25 °C) using an AUTOLAB Potentiostat (PGSTAT30. Results show that open circuit potential (OCP) revealed that mild steel specimen in 3.5% NaCl solution has higher tendency to corrode compared to when it is immersed in 1 M H2SO4. However, the potentiodynamic polarization measurement shows that lower current density was produced for mild steel specimen immersed in 3.5% NaCl solution compared to 1 M H2SO4 solution. The chronoamperometry measurement for 3.5% NaCl sample illustrated that when a nobler potential was applied, it resulted into lower corrosion current while it is the opposite for samples immersed in 1 M H2SO4.