Characterization of calcareous deposits in artificial seawater by impedance techniques

Barchiche, C.; Deslouis, C.; Festy, D.; Gil, O.; Refait, Philippe; Touzain, S.; Tribollet, Bernard

doi:10.1016/s0013-4686(03)00075-6

Cited by 168 publications

(101 citation statements)

References 13 publications

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“…Room temperature data suggest that calcareous deposits are usually formed on steel under cathodic protection, being composed of a thin Mg-rich layer on the steel surface with a Ca-rich layer on top of the Mg-rich layer [16][17][18][19]. Somehow, the conditions of this experiment did not allow the Ca-rich layer to form.…”

Section: Discussionmentioning

confidence: 78%

“…This, however, is only true for lower temperatures, as higher temperatures tend to shift (lower) the neutral point of water as well as the minimum pH required for the precipitation of brucite (Tables 4 and 5). The reason for the increase in the surface pH that results in the precipitation of calcareous matter has been studied before [16][17][18][19][20]. The anode (aluminum, in the case of TSA-coated steel) polarizes the steel, resulting in the production of hydroxyl ions (OH − ), which increases the interfacial pH.…”

Section: Discussionmentioning

confidence: 99%

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Thermally Sprayed Aluminum Coatings for the Protection of Subsea Risers and Pipelines Carrying Hot Fluids

Cé

Paul

2016

Coatings

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This paper reports the effect of boiling synthetic seawater on the performance of damaged Thermally Sprayed Aluminum (TSA) on carbon steel. Small defects (4% of the sample's geometric surface area) were drilled, exposing the steel, and the performance of the coating was analyzed for corrosion potential for different exposure times (2 h, 335 h, and 5000 h). The samples were monitored using linear polarization resistance (LPR) in order to obtain their corrosion rate. Scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were used for post-test characterization. The results showed that a protective layer of Mg(OH) 2 formed in the damaged area, which protected the underlying steel. Additionally, no coating detachment from the steel near the defect region was observed. The corrosion rate was found to be 0.010-0.015 mm/year after 5000 h in boiling synthetic seawater.

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Section: Discussionmentioning

confidence: 78%

Section: Discussionmentioning

confidence: 99%

Thermally Sprayed Aluminum Coatings for the Protection of Subsea Risers and Pipelines Carrying Hot Fluids

Cé

Paul

2016

Coatings

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“…Cathodic protection often results in the formation of calcareous deposits on the metal surface in sea water [18][19][20][21][22][23]. The cathodic reactions of dissolved oxygen reduction or water reduction to evolve hydrogen at more negative potential will generate hydroxyl ions, with increasing the pH value of the electrolyte adjacent to the metal surface, which will promote the formation of calcareous deposits [19,[21][22][23].…”

Section: Introductionmentioning

confidence: 99%

“…The cathodic reactions of dissolved oxygen reduction or water reduction to evolve hydrogen at more negative potential will generate hydroxyl ions, with increasing the pH value of the electrolyte adjacent to the metal surface, which will promote the formation of calcareous deposits [19,[21][22][23]. Some works indicate that CaCO 3 is saturated at pH 8.7 or even lower in normal sea water and is ready to deposit as the inorganic carbonic equilibrium in the electrolyte is changed, while the critical pH value for Mg(OH) 2 to deposit is about 9.3 [24,25].…”

Section: Introductionmentioning

confidence: 99%

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Evolution of Calcareous Deposits and Passive Film on 304 Stainless Steel with Cathodic Polarization in Sea Water

Sun

Huang

et al. 2018

Coatings

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Abstract:The change of protective current density, the formation and growth of calcareous deposits, and the evolution of passive film on 304 stainless steel (SS) were investigated at different potentials of cathodic polarization in sea water. Potentiostatic polarization, electrochemical impedance spectroscopy (EIS), and surface analysis techniques of scanning electron microscopy (SEM), energy dispersive X-ray (EDX) microanalysis and X-ray diffraction (XRD) were used to characterize the surface conditions. It was found that the protective current density was smaller for keeping polarization at −0.80 V (vs. saturated calomel electrode (SCE), same as below) than that at −0.65 V. The calcareous deposits could not be formed on 304 SS with polarization at −0.50 V while it was well protected. The formation rate, the morphology, and the constituent of the calcareous deposits depended on the applied potential. The resistance of passive film on 304 SS decreased at the first stage and then increased when polarized at −0.80 V and −0.65 V, which was related to the reduction and the repair of passive film. For the stainless steel polarized at −0.50 V, the film resistance increased with polarization time, indicating that the growth of oxide film was promoted.

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Numerical simulation and re‐design optimization of impressed current cathodic protection for an offshore platform with biofouling in seawater

Wang

Song

et al. 2017

Materials & Corrosion

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A finite element model (FEM) of the offshore platform with biofouling is developed here to predict the effectiveness of the ICCP under seawater. Remotely operated vehicle (ROV) test verified that the offshore platform was fully covered by a coating‐like biofouling to protect the structures from corrosion. FE‐SEM and EDS tests demonstrated that the biofouling deposits on the offshore platform mainly contained magnesium oxides, biofouling deposits, and corrosion products doped with calcium oxides. The polarization relationships of platform steel with biofouling coverage were used as boundary conditions for the numerical simulation. Furthermore, the factors including output current, anode location, seawater conductivity, and biofouling coverage rate, which influenced the protective effectiveness, were comparatively evaluated by FEM. Then, a re‐design two‐anode ICCP system was employed to keep offshore platform in protective condition. A ROV monitored the potential distributions of the legs and demonstrated that numerical simulation results of ICCP had a good agreement with measured data.

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Characterization of calcareous deposits in artificial seawater by impedance techniques

Cited by 168 publications

References 13 publications

Thermally Sprayed Aluminum Coatings for the Protection of Subsea Risers and Pipelines Carrying Hot Fluids

Thermally Sprayed Aluminum Coatings for the Protection of Subsea Risers and Pipelines Carrying Hot Fluids

Evolution of Calcareous Deposits and Passive Film on 304 Stainless Steel with Cathodic Polarization in Sea Water

Numerical simulation and re‐design optimization of impressed current cathodic protection for an offshore platform with biofouling in seawater

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