Abstract
This study was structured on the uncertainty of events that comes with internal pipe corrosion. Hitherto, the study of corrosion was structured on the combined effect of electrochemical activities (chemical dissolution) and flow properties (hydrodynamics) being the main parameter controlling the physical characteristics by forming semi-permeability or partial protective corrosion product barrier between the steel surface and the flowing MME/SSW solution. To disseminate the knowledge and raise the level of understanding, a multi specimen electrochemical test-rig prototype was developed to study the corrosion behaviour of mild steel in mine effluent (MME) and synthetic seawater (SSW). The electrochemical impedance spectroscopy (EIS) data showed the SSW corrosion-product charge transfer resistance (R2) decreased from 18597 Ohm to 3.367 Ohm with flow rate. The lower the charge transfer resistance indicates a high mild steel dissolution rate. Hence, a decrease in charge transfer (R3) with exposure time. The MME experiments were marked by a low charge transfer resistance (R3), hence the high corrosion rate (CR). The (a) factor indicated the permeability of the multi-layered corrosion film, thus, whether or not the multi-layer film behaved like a capacitor. The behaviour was supported by the constant phase element (Q3) which increased with CR...
M.Tech. (Engineering Metallurgy)