Cathodic Protection

Popov, Branko N.

doi:10.1016/b978-0-444-62722-3.00015-x

Cited by 5 publications

(11 citation statements)

References 40 publications

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“…It may allow the reduction of Zn and, in the end, total loss of the cathodic protection system. Therefore, high conductivity is required for these protective coatings to protect metals. − To obtain a well-established electrical connection, the Zn content in dry film thickness (DFT) should be above 90 wt %, which means the pigment volume concentration (PVC) should be close to or above critical PVC (CPVC). ,− The protective behavior of CGCs is strongly affected by PVC, , P/B ratio, particle size and shape, and DFT …”

Section: Introductionmentioning

confidence: 99%

Investigation of Cathodic Protection, Morphological, Rheological, and Mechanical Properties of Graphene/Iron Oxide Nanoparticle-Embedded Cold Galvanizing Compounds at Reduced Pigment Volume Concentration

2022

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The ultimate goal of this research was to produce a cold galvanizing compound (CGC) at reduced pigment volume concentration (PVC) to protect metallic structures from corrosion attacks. The influence of partial replacement of Zn by nanolayered graphene (NGr) and red iron oxide (Fe 2 O 3 ) nanoparticles on the electrochemical, morphological, rheological, and mechanical properties of CGCs was investigated. Electrochemical impedance spectroscopy (EIS) was used to investigate the electrochemical nature of coatings. The EIS results revealed that the partial replacement of Zn by NGr and Fe 2 O 3 nanoparticles enhanced the cathodic protection at reduced PVC (4:1) by improving the electrical contact between the Zn particles and the metal substrate. The Tafel scan was conducted to support the cathodic behavior of the coatings. It was found that the sample formulated solely with Zn at PVC 4:1 was dominated in physical barrier characteristics over cathodic protection. By increasing the concentration of NGr in the formulation, the corrosion potential shifted toward a more negative side, and the coating with 1.5% NGr showed the highest galvanic action at reduced PVC. Field-emission scanning electron microscopy confirmed the interconnected network of conducting particles. The coating without NGr and Fe 2 O 3 at PVC 4:1 showed significant gaps between the Zn particles. The novelty was evidenced when micrographs showed the consistent distribution of NGr and Fe 2 O 3 nanoparticles all over the surface, which acted as a bridge between spherical Zn particles and provided cathodic protection at a reduced PVC. The layered structure of graphene also improved the physical shielding effect of the coatings, which limited the diffusion of electrolytes and corrosion products (oxides/hydroxides) into the coatings, which was reflected by the salt spray test. The rheological properties of coatings were studied in continuous ramp, peak hold step, temperature ramp, and frequency sweep oscillation experiments. All the coatings showed good liquid/fluid properties. The coatings having less PVC displayed better flow behavior during the application due to the less frictional forces in the internal structure. All the coatings showed excellent adhesion but had different strength values. In NGr/Fe 2 O 3 -modified coatings, the strength increased from 7.14 to 14.12 Mpa at reduced PVC. The addition of NGr provided an additional chemical bonding (galvanic action) to steel, which supported the physical adhesion and increased the overall adhesion strength. A real-time scratch resistance assessment showed that all the coatings had good scratch resistance due to the solid interconnection between Zn, NGr, and Fe 2 O 3 particles.

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Section: Introductionmentioning

confidence: 99%

Investigation of Cathodic Protection, Morphological, Rheological, and Mechanical Properties of Graphene/Iron Oxide Nanoparticle-Embedded Cold Galvanizing Compounds at Reduced Pigment Volume Concentration

2022

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“…The current will flow from the newly presented sacrificial metal as an anode, making the protected metal the cathode, creating a galvanic cell. Must reactions then will be transferred from the metal surface to the galvanic anode and are thus the anode is sacrificed in favour of the protected metals in the marine environment [22], [23].…”

Section: Cathodic Protection and Sacrificial Anodesmentioning

confidence: 99%

“…Figure6-23 shows Nyquist plots for both BZI-SBX-80 and OA-SBX-80 coatings from 01hr to 360 hrs respectively. These plots were used for equivalent circuits modelling fitting by using ZSimpwin electrochemical impedance spectroscopy (EIS) data analysis software.…”

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confidence: 99%

Development of Hybrid Sol-Gel Coatings on AA2024-T3 with Environmentally Benign Corrosion Inhibitors

Mussa¹

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Aluminium alloys are still considered as one of the primary light alloys with high strength that can be used in aerospace and marine structure with a moderate economic cost. However, aluminium alloys are affected by atmospheric and marine corrosion which reduces their overall reliability. The application of coatings is one of the strategies for mitigating the corrosion on aluminium alloys. Sol-gel technology is one of the coating strategies with potential for excellent chemical and environment stability, providing eco-friendly performance improvement. Sol-gel coatings can enhance corrosion resistance by adopting many corrosion inhibitors that can protect aluminium alloys substrates from corrosion.

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“…From the start of this century, thousands of miles of buried pipelines and cables have been effectively protected by cathodic protection. The common applications using cathodic protection are such as ships, offshore floaters, offshore drilling structures, subsea equipment, harbors, pipelines, storage tanks, concrete structures; all submerged or buried metal structures [5,7].…”

Section: Cathodic Protectionmentioning

confidence: 99%

“…Based on the type of the polarization used to protect the structure, cathodic protection systems are divided into impressed current systems or sacrificial anode [7].…”

Section: Cathodic Protectionmentioning

confidence: 99%

Effect of thiosulfate on the passivation of zinc-alloyed anodes, (Z32120 and Z13000) at 80?C after 288h immersion in 3.5% NaCl solution

Zaw

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In this research, the inhibition of passivation on Zn alloys (Z32120 with Al) and Z13000�without Al) in artificial seawater (3.5% NaCl) mixing with different thiosulfate concentrations (100ppm, 150ppm, 200ppm) were investigated electrochemically after 288h immersion at 80?C and compared the results with that of testing without thiosulfate in the environment. According to the Potentiodynamic polarization test results, it is found that the presence of thiosulfate (S2O32-)�in the solution hinders the passivation that was formed during the immersion of Zn alloys between 120h and 288h at 80?C in the absence of thiosulfate. Thiosulfate effect promotes Cl-�penetration for not only hinderance of the passivation but also generating the depassivation of passive films�resulting in�retarding repassivation. It is confirmed by the comparison between polarization test results of testing without thiosulfate and with thiosulfate in the solution. However, although all thiosulfate concentrations used in the study impedes the passivation, the different thiosulfate concentration gives the different effectiveness depending on the immersion time and temperature. Also, Al presence in the Zn alloys supports the different effectiveness. The lower thiosulfate concentration (100ppm) exhibits the decrease of current density at longer immersion for Z32120 whilst Z13000�exhibits the�decrease of the current density at higher thiosulfate concentration (200ppm). Regarding the results investigated in this study, Z32120 is effective with 150ppm and 200ppm thiosulfate meanwhile Z13000 is better result with 100ppm and 150ppm. Therefore, 150ppm is considered to be the proper and average value for both Zn alloys. The effect of thiosulfate on passivation of both Zn alloys was discussed based on immersion time, temperature, pH, and the ratio of Cl-�and�S2O32-.

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Cathodic Protection

Cited by 5 publications

References 40 publications

Investigation of Cathodic Protection, Morphological, Rheological, and Mechanical Properties of Graphene/Iron Oxide Nanoparticle-Embedded Cold Galvanizing Compounds at Reduced Pigment Volume Concentration

Investigation of Cathodic Protection, Morphological, Rheological, and Mechanical Properties of Graphene/Iron Oxide Nanoparticle-Embedded Cold Galvanizing Compounds at Reduced Pigment Volume Concentration

Development of Hybrid Sol-Gel Coatings on AA2024-T3 with Environmentally Benign Corrosion Inhibitors

Effect of thiosulfate on the passivation of zinc-alloyed anodes, (Z32120 and Z13000) at 80?C after 288h immersion in 3.5% NaCl solution

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