Abstract
The influence of dissolved oxygen on calcareous deposits formed under galvanostatic polarization mode was studied. When the dissolved oxygen concentration was less than 7 mg L−1, the cathodic protection potential showed a plateau at the initial polarization, and then quickly shifted negatively. While the dissolved oxygen was more than 9 mg L−1, the potential shifted negatively in a linear form. After 168 h of polarization, the final protection potential shifted negatively with the decreasing dissolved oxygen concentration. The deposition progress was monitored by electrochemical impedance spectroscopy, and only one single loop was found in Nyquist diagram, indicating deposits of ineffective protectiveness precipitation under the experimental conditions. The protection factor of deposits increased with the decreasing dissolved oxygen concentration which was detected by linear polarization resistance technique. The cathodic electrochemical reaction could change very shortly from oxygen reduction to hydrogen evolution after cathodic protection under very low dissolved oxygen concentration, such as 1 mg L−1, resulting in the hydrogen bubbling from the metallic surface and the decrease of deposits protection factor. Observation by scanning electron microscopy and X-ray diffraction analysis demonstrated that the deposits were mainly of calcite under the experimental conditions, and that dissolved oxygen had no effect on the crystalline types of calcium carbonate.
Similar content being viewed by others
References
Barchiche, C., Deslouis, C., Festy, D., and Gil, O., 2003. Characterization of calcareous deposits in artificial seawater by impedance techniques: 3-Deposit of CaCO3 in the presence of Mg (II). Electrochimica Acta, 48: 1645–1654.
Barchiche, C., Deslouis, C., Gil, O., Refait, P., and Tribollet, B., 2004. Characterisation of calcareous deposits by electrochemical methods: Role of sulphates, calcium concentration and temperature, Electrochimca Acta, 49: 2833–2839.
Benedetti, A., Magagnin, L., Passaretti, F., Chelossi, E., Faimali M., and Montesperelli, G., 2009. Cathodic protection of carbon steel in natural seawater: Effect of sunlight radiation, Electrochimca Acta, 54: 6472–6478.
Chen, S., and Hartt, W. H., 2002. Deepwater cathodic protection: Part 1: Laboratory simulation experiments. Corrosion, 58: 38–48.
Chen, S., Hartt, W. H., and Wolfson, S., 2003. Deep water cathodic protection: Part 2: Field deployment results. Corrosion, 59: 721–732.
Deslouis, C., Festy, D., Gil, O., Rius, G., Touzain, S., and Tribollet, B., 2000. Characterization of calcareous deposits in artificial sea water by impedance techniques-2. Deposit of Mg(OH)2 without CaCO3. Electrochimca Acta, 45: 1837–1845.
Fischer, K. P., Espelid, B., and Veritas, D. N., 2001. A review of cp current demand and anode performance for deep water, Corrosion, NACE International, Houston, TX, 1–6.
Festy, D., 2001. Cathodic protection of steel in deep sea: Hydrogen embrittlement risk and cathodic protection, Corrosion. NACE International, Houston, TX, 1–11.
Hartt, W. H., 2012. Protection of offshore structures -History and current status. Corrosion, 68: 1063–1075.
Kunjapur, M. M., Hartt, W. H., and Smith, S. W., 1987. Influence of temperature and exposure time upon calcareous deposits. Corrosion, 43: 674–679.
Lee, R. U., and Ambrose, J. R., 1988. Influence of cathodic protection parameters on calcareous deposit formation. Corrosion, 44: 887–891.
Li, C. J., Du, M., Qiu, J., Zhang, J., and Gao, C. J., 2014. Influence of temperature on the protectiveness and morphological characteristics of calcareous deposits polarized by galvanostatic mode. Acta Metallurgica Sinica (English Letters), 27: 131–139.
Refait, P., Jeannin, M., Sabot, R., Antony, H., and Pineau, S., 2013. Electrochemical formation and transformation of corrosion products on carbon steel under cathodic protection in seawater. Corrosion Science, 71: 32–36.
Rossi, S., Bonora, P. L., Pasinetti, R., Benedetti, L., Draghetti, M., and Sacco, E., 1998. Laboratory and field characterization of a new sacrificial anode for cathodic protection of offshore structures. Corrosion, 54: 1018–1025.
Rousseau, C., Baraud, F., Leleyter, L., Jeannin, M., and Gil, O., 2010. Calcareous deposit formed under cathodic protection in the presence of natural marine sediments: A 12 month experiment. Corrosion Science, 52: 2206–2218.
Sun, W., Liu, G. C., Wang, L. D., and Li, Y., 2012. A mathematical model for modeling the formation of calcareous deposits on cathodically protected steel in seawater. Electrochimica Acta, 78: 597–608.
Tawns, A., Stena, C., Limited, O., House, S., Drive, E., Oakley, R., and Centre, S. M., 2000. Cathodic protection at a simulated depth of 2500 m, Corrosion2000, NACE International, Orlando, Fl.
Yan, J. F., White, R. E., and Griffin, R. B., 1993. Parametric studies of the formation of calcareous deposits on cathodically protected steel in seawater. Journal of the Electrochemical Society, 140: 1275–1280.
Zamanzade, M., Shahrabi, T., and Yazdian, A., 2007. Improvement of corrosion protection properties of calcareous deposits on carbon steel by pulse cathodic protection in artificial sea water. Anti-Corrosion Methods and Materials, 54: 74–81.
Acknowledgements
The authors gratefully acknowledge the financial support of this project by the National Basic Research Program of China (973 Project, No. 2014CB643300) and National Environmental Corrosion Platform (NECP).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Li, C., Du, M. & Gao, R. Influence of dissolved oxygen on the protectiveness and morphological characteristics of calcareous deposits with galvanostatic polarization. J. Ocean Univ. China 16, 243–248 (2017). https://doi.org/10.1007/s11802-017-2933-4
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11802-017-2933-4