Development of a novel recirculation apparatus to study flow accelerated corrosion of mild steel.

This study reports the development and application of a novel apparatus on the effect of flow properties on the mild steel corrosion in mimic and real-life industrial environments. Gravimetric, electrochemical, and microstructural techniques were used to assess the performance of carbon steel in synthetic seawater (3.6 wt% NaCl) and a gold mine water effluent. The in-situ electrochemistry includes the application of open circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy. In the apparatus, the working electrode is mild steel positioned at 180⁰ to the bend, the reference electrode is a saturated calomel electrode (SCE), and the counter electrode is a graphite rod. Flow velocities have been calibrated. A series of experiments were conducted to determine the effect of the exposure period (24 and 192 hours) and the influence of flow velocities (0.018 and 0.062 m/s). Pre and post immersion of the mild steel in the environments were assessed with the aid of scanning electron microscope (SEM). Electrochemical measurements results were compared with morphological and topographical information obtained from the scanning electron microscope (SEM).