Dissolved Oxygen and pH Microelectrode Measurements at Water-Immersed Metal Surfaces

Lewandowski, Zbigniew; Lee, Whonchee; Characklis, William G.; Little, Brenda J.

doi:10.5006/1.3577838

Cited by 67 publications

(28 citation statements)

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“…Salgavo et al [8] analyzed alloy 600 (UNS N06600) sample cathodically polarized to −0.8 V to −1.2 V (Ag/AgCl) in natural seawater at temperatures between 13 • C and 27 • C. The probe was 1 mm from the metal surface and the maximum pH value recorded was 10.7 at −1.2 V (Ag/AgCl). Lewandowski et al [12] found pH values between 9.5 and 10 at −1.0 V (SCE) on 304 stainless steel (AISI 304SS) surface in synthetic seawater at room temperature. The distance between the pH microelectrode and the stainless steel surface was not specified.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Temperature and Local pH on Calcareous Deposit Formation in Damaged Thermal Spray Aluminum (TSA) Coatings and Its Implication on Corrosion Mitigation of Offshore Steel Structures

Cé

Paul

2017

Coatings

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This paper is based on experimental data and provides better understanding of the mechanism of calcareous deposit formation on cathodically polarized steel surfaces exposed to synthetic seawater at 30 • C and 60 • C. The study comprises measurement of the interfacial pH of thermally sprayed aluminum (TSA) coated steel samples with and without a holiday (exposing 20% of the surface area). Tests were conducted at the corrosion potential for up to 350 h. It was experimentally determined that the local pH adjacent to the steel surface in the holiday region reached a maximum of 10.19 and 9.54 at 30 • C and 60 • C, respectively, before stabilizing at about 8.8 and 7.9 at the two temperatures. The interfacial pH on the TSA coating at 30 • C was initially 7.74 dropping to 4.76 in 220 h, while at 60 • C it increased from pH 6.41 to the range pH 7.0-8.5. The interfacial pH governed the deposition of brucite and aragonite from seawater on the steel surface cathodically polarized by the TSA. This mechanism is likely to affect the performance of TSA-coated offshore steel structures, especially when damaged in service.

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Section: Introductionmentioning

confidence: 99%

The Effect of Temperature and Local pH on Calcareous Deposit Formation in Damaged Thermal Spray Aluminum (TSA) Coatings and Its Implication on Corrosion Mitigation of Offshore Steel Structures

Cé

Paul

2017

Coatings

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“…Lewandowski et al [73] and Lewandowski [74] used microelectrodes to determine the oxygen concentration around a microcolony. The microcolony was anoxic in the middle, but oxygen was detected at the bottom, demonstrating transport via channels and voids in addition to diffusion.…”

Section: C14 Microsensorsmentioning

confidence: 99%

Diagnosing, Measuring, and Monitoring Microbiologically Influenced Corrosion

Little

Lee

Ray

2011

Uhlig's Corrosion Handbook

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“…It should be noted from Figure 10 that only the deposits formed by polarization at −0.80 V contained the Mg element. Usually, magnesium hydroxide precipitates in sea water at a critical pH value as high as 9.3 or more [5,44]. This implies that applied polarization at −0.80 V can result in local environment of high pH at the interface of metal and electrolyte, which promotes the deposit of Mg(OH) 2 .…”

Section: Edx Analysismentioning

confidence: 99%

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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Dissolved Oxygen and pH Microelectrode Measurements at Water-Immersed Metal Surfaces

Cited by 67 publications

References 0 publications

The Effect of Temperature and Local pH on Calcareous Deposit Formation in Damaged Thermal Spray Aluminum (TSA) Coatings and Its Implication on Corrosion Mitigation of Offshore Steel Structures

The Effect of Temperature and Local pH on Calcareous Deposit Formation in Damaged Thermal Spray Aluminum (TSA) Coatings and Its Implication on Corrosion Mitigation of Offshore Steel Structures

Diagnosing, Measuring, and Monitoring Microbiologically Influenced Corrosion

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

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