Corrosion propagation monitoring using electrochemical noise measurements on carbon steel in hydrogenocarbonated solution containing chloride ions
Introduction
Localized corrosion sometimes occurs freely on passive surfaces in the presence of aggressive anionic species like chloride ions. It proceeds according to several stages: passive film breakdown and metastable pitting, then stable pit growth. When localized corrosion occurs, an electrochemical coupling is established between the free surfaces and the confined zones in which the chemical composition of the medium is strongly modified [1], [2]. Many authors studied localized corrosion of carbon steel at Open Circuit Potential (OCP) or under polarization in different passivating media containing chloride ions such as simulated concrete pore solution [3], [4], saturated Ca(OH)2 [3], [5], [6], [7], NaNO2 [8], [9], or NaHCO3 [8], [10], [11] using deterministic electrochemical techniques (polarization curves, electrochemical impedance spectroscopy (EIS)…).
Localized corrosion of carbon steel induced by chloride ions in these environments was also studied by Electrochemical Noise Measurements (ENM) to detect the onset of corrosion, identify its mechanism and quantify the damage caused by a given corrosion mode [6], [12], [13], [14]. It is well known that ENM presents potentialities for such application [15], [16]. This non-intrusive technique consists in measuring the random fluctuations of electrical parameters such as the potential of the electrode and/or the current flowing through it when an electrochemical process takes place at the material-environment interface. Measurements can be carried out in galvanostatic, potentiostatic or zero resistance ammeter (ZRA) modes. The latter mode involves two electrodes, most commonly identical, coupled to each other to measure both current and voltage fluctuations. The current generated by the electrochemical processes is measured between the two electrodes while their coupling potential is monitored using a reference electrode [17], [18]. A metastable corrosion process (breakdown and repassivation of passive film) can often be identified from the signature of the current or potential transients that can have different shapes according to the metal undergoing corrosion: for stainless steel, the current transient due to a pit is characterized by a slow rise followed by a sharp drop while a sudden rise followed by a slow decay can be observed for carbon steel [15]. Potential transients can present such characteristics too but they are also influenced by the charge and discharge of the capacitance of the passive film [12].
The objective of the present paper is to investigate propagation of localized corrosion on API 5L X65 carbon steel during long immersion times (up to 100 h) in NaHCO3 aqueous solution containing chloride ions at OCP using ENM and to evaluate the capacities and limitations of the EN technique for such study. Indeed, the EN technique is generally used to detect the onset of localized corrosion, not its propagation on long times. Great care was taken for validating the ENM and identify the influence of the instrumentation noise sometimes present.
Section snippets
Experimental
The tested material was an API 5L X65 grade carbon steel whose chemical composition is given in Table 1. The samples were rectangular plates of 30 × 100 mm dimensions and thickness of 3 mm (Fig. 1). After grinding up to 1200 grit SiC paper, one side and the cut edges of the samples were covered with a thin layer of cataphoretic paint (black color in Fig. 1) commonly used in the automotive industry for its anticorrosion properties, leaving one side of 7.5 or 1.5 cm2 surface area exposed to
Procedure and validation
ENM were performed using the Gamry® ESA 410® software in ZRA mode. The electrochemical cell was placed in a Faraday cage connected to the floating ground of the potentiostat in order to reduce the mains interference (50 Hz and harmonics) [19]. In this work, the noise measurements were performed in three successive steps by using sampling frequencies fs of 10 Hz during 28 min, 1 Hz during 70 min and 10 Hz during 28 min with an I-E range of 6 or 60 µA corresponding to a current-measuring
Preliminary study
Fig. 3a. presents the time evolution of the OCP of single API 5 L X65 carbon steel electrodes of surface area of 27.3 cm2 immersed in 0.5 M NaHCO3 without, for test 1, or with 0.2 M NaCl for the three other tests. In 0.5 M NaHCO3, the free corrosion potential of the electrode shifted to positive values resulting from the formation of a protective barrier layer on the metal [10], [23]. Indeed, NaHCO3 reacts with ferric ions when the concentration of HCO3- is high enough to saturate the solution
Conclusion
This paper is aimed at studying the propagation of localized corrosion on API 5 L X65 carbon steel electrodes in a 0.5 M NaHCO3 solution containing chloride ions using electrochemical noise measurements. While the EN technique is generally used to detect the early stage of localized corrosion, long-term experiments (about 100 h) were performed to investigate the corrosion propagation and assess the suitability of the EN technique for such study.
The main conclusions drawn from the analysis of
CRediT authorship contribution statement
C. Comas: Conceptualization, Methodology, Investigation, Validation, Formal analysis, Writing – Original draft, Data curation. F. Huet: Conceptualization, Methodology, Supervision, Validation, Formal analysis, Data curation, Writing – Original draft, Visualization, Software, Writing – review & editing. K. Ngo: Conceptualization, Methodology, Writing – Review & Editing, M. Fregonese: Project administration, Funding acquisition, Conceptualization, Supervision, Resources. H. Idrissi: Supervision,
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
This operation was conducted with the assistance of the " Investissements d′avenir " (FIA) program of the French government, the management of which has been entrusted to Andra (French national radioactive waste management agency).
References (27)
- et al.
A study on chloride-induced depassivation of mild steel in simulated concrete pore solution
Cem. Concr.
(2002) - et al.
Carbon steel passivity examined in alkaline solutions: the effect of chloride and nitrite ions
Electrochim. Acta
(2008) - et al.
Effect of phosphate based inhibitor on the threshold chloride to initiate steel corrosion in saturated hydroxide solution
Constr. Build. Mater.
(2014) - et al.
Initiation and repassivation of pitting corrosion of carbon steel in carbonated concrete pore solution
Corros. Sci.
(2011) - et al.
Effect of phosphate-based inhibitor on prestressing tendons corrosion in simulated concrete pore solution contaminated by chloride ions
Constr. Build. Mater.
(2018) - et al.
The metastable pitting behaviors of mild steel in bicarbonate and nitrite solutions containing Cl-
Corros. Sci.
(2008) - et al.
The inhibitive mechanisms of nitrite and molybdate anions on initiation and propagation of pitting corrosion for mild steel in chloride solution
Appl. Surf. Sci.
(2015) - et al.
Localised corrosion of carbon steel in NaHCO3/NaCl electrolytes: role of Fe(II)-containing compounds
Corros. Sci.
(2006) - et al.
The role of chloride ions in pitting of carbon steel studied by the statistical analysis of electrochemical noise
Appl. Surf. Sci.
(1999) - et al.
Crevice corrosion behavior of A516-70 carbon steel in solutions containing inhibitors and chloride ions
Thin Solid Films
(1998)
Monitoring of carbon steel corrosion by use of electrochemical noise and recurrence quantification analysis
Corros. Sci.
Passivation of X65 (UNS K03014) carbon steel in NaHCO3 solution in a CO2 environment
Corros. Sci.
Pitting corrosion of metals. A review of critical factors
J. Electrochem. Soc.
Cited by (12)
Unraveling the influence of Mo on the corrosion mechanism of Ni-advanced weathering steel in harsh marine atmospheric environments
2024, Journal of Materials Science and TechnologyElectrochemical noise energy generated by nickel electroplating process
2023, Transactions of Nonferrous Metals Society of China (English Edition)Failure analysis on weld joint of centrifugal pump diffuser for oil and gas pipeline transportation
2022, Engineering Failure AnalysisCitation Excerpt :Otherwise, K, Ca, and other elements were also found in the EDS test results of the three position, indicating that slag inclusion and other defects existed in the weld joint. Elements K, Na, and Ca are one of the main components of the electrode coating used in welding [25]. Fig. 4 shows the SEM appearance on the surface of sample 2.
Cobalt-phosphorous coatings with tunable composition fabricated by additive-controlled electrodeposition from choline chloride-ethylene glycol deep eutectic solvent for anti-corrosion application
2022, Surface and Coatings TechnologyCitation Excerpt :As a result, the corrosion attack at the coating/substrate interface is similar to the case in Fig. 10a. This corrosion of the internal substrate continues to extend along with the depth of the coating-substrate interface, eventually leading to the local collapse of the coating surrounding the micropores [75,76]. Co-P-SA12 with a high P content and improved morphology can significantly limit coating surface disintegration.