Fig. 1 Schematic illustrations of the electrochemical cell and temperature control

Fig. 2 Curves of the potential decay versus time at various temperatures by galvanostatic polarization at 200 mA/m2

Fig. 3 Nyquist diagrams at various temperatures: a without polarization (blank); b galvanostatic polarization for 168 h

Fig. 4 Schematic of the electrical equivalent circuit: a bare steel; b steel surface covered by calcareous deposits

Fig. 5 aRp versus temperature; bFp versus temperature curves after galvanostatic polarized for 168 h

Fig. 6 SEM observations of the deposits obtained at various temperatures by galvanostatic polarization for 168 h: a 30 °C; b 25 °C; c 20 °C; d 15 °C; e 10 °C; f 5 °C

Fig. 7 XRD analysis of the deposits formed at 20 °C a and 15 °C b on a steel substrate (A the diffraction lines of aragonite, C calcite, and α-Fe the steel substrate)

Fig. 8 High-magnification SEM images of deposits crystals at various temperatures: a 20 °C; b 15 °C

Fig. 9 a Nyquist diagrams versus time; bFp versus time curve at 25 °C by galvanostatic polarization

Fig. 10 a SEM image of the new bare steel surface; b EDX spectra of the particular area after deposits exfoliated at 25 °C