DETERMINATION OF CARBON STEEL CORROSION RATE AT LOW CORROSION POTENTIALS BY MEANS OF A NEW ELECTROCHEMICAL METHOD

1 KOUŘIL Milan
Co-authors:
1 WIENEROVÁ Kateřina 2 NOVÁK Pavel 1 MSALLAMOVÁ Šárka 1 STOULIL Jan
Institutions:
1 Deparment of Metals and Corrosion Engineering, University of Chemistry and Technology Prague, Czech Republic, EU
2 Department of Chemical Technology of Monument Conservation, University of Chemistry and Technology Prague, Czech Republic, EU
Conference:
25th Anniversary International Conference on Metallurgy and Materials, Hotel Voronez I, Brno, Czech Republic, EU, May 25th - 27th 2016
Proceedings:
Proceedings 25th Anniversary International Conference on Metallurgy and Materials
Pages:
1115-1120
ISBN:
978-80-87294-67-3
ISSN:
2694-9296
Published:
14th December 2016
Proceedings of the conference were published in Web of Science and Scopus.
Metrics:
84 views / 29 downloads
Abstract

Determination of corrosion rate by means of electrochemical methods such as polarization resistance is limited to open-circuit conditions. In the case of cathodic protection, a protected object is polarized to protection potential by means of negative total current, the value of which is thus useless for quantifying corrosion rate. Long-time response physical methods, such as weight loss or electrical resistance technique are only applicable for corrosion rate determination under cathodic polarisation. A novel electrochemical method employing two working electrodes allows us to determine instantaneous corrosion rate at impressed potential even if the total current is negative. Anodic current density is extracted from two consecutively measured currents. The shape of the carbon steel corrosion rate curve at the impressed potential in the potassium carbonate solution was determined. At pH 11, carbon steel was spontaneously passive, however, at cathodic polarization to the Kuhn's protective potential, substantially elevated corrosion rate was indicated. The shape of the corrosion rate – impressed potential curve was confirmed by electrical resistance sensors exposed to aerated aqueous electrolyte under the same conditions.

Keywords: Double-electrode; Cathodic protection; Corrosion rate; Carbon steel

© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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