Influence of Temperature Variation on the Formation and Corrosion Protective Performance of Calcium Carbonate Deposits in Artificial Seawater

摘要

The aim of this research was to investigate the influence of temperature variation on the formation and protective behavior of calcium carbonate scale deposited on steel electrodes in artificial seawater. Chronoamperometry measurement, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM) and x-ray diffraction (XRD) were employed for analysis. An increase in temperature from 20 to 50 degrees C accelerated the oxygen reduction reaction, which increased the nucleation/deposition rate. The chronoamperometry, SEM and XRD results indicated that complete coverage of the electrode surface was achieved at higher temperatures because a denser layer of scale deposits covered the entire surface of the metal and acted as a barrier against the passage of oxygen. The EIS results showed that better corrosion protection was obtained after deposition that included a stepwise decrease in temperature, indicating fewer pathways through the deposited layer onto the electrode surface.