Influence of Temperature on the Protectiveness and Morphological Characteristics of Calcareous Deposits Polarized by Galvanostatic Mode

The influence of temperature on calcareous deposits formed under galvanostatic polarization mode was studied. The deposition was monitored by electrochemical impedance spectrum, and a supplementary loop in Nyquist diagram at high frequency was found to be an indicator of deposits precipitation with sufficient protection at above 20 °C. An exponential increase of protectiveness with temperature was observed, which was quantified by linear polarization resistance technique. Observation by scanning electron microscope and X-ray diffraction analyses demonstrated that the critical temperature of calcium carbonate crystal form transition ranged from 15 to 20 °C. Calcite formed below 15 °C, while aragonite precipitated at above 20 °C.