Effects of Cathodic Protection on Steel Surface in Tidal Zone

In recent years, a wide agreement with respect to the processes associated with cathodic protection (CP) has been reached within the CP industry. The increase of the pH value at the steel surface and the generation of passivating conditions as a result of the CP current are widely accepted as the relevant underlying mechanism. Based on this understanding it was possible to identify the relevant processes with respect to AC and DC interference and explain the empirical observations. This led to the development of ISO 18086 and has significantly influenced the work on ISO/DIS 21857. This paper summarizes present state of knowledge, the more recent developments, and their implications with respect to the CP criteria. It summarizes the relevant aspects in association with interference conditions and highlights possible future approaches with respect to the assessment of the effectiveness of CP.

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Study on Paint Degradation and Corrosion of Paint-Coated Steel with Defects under Cathodic Protection in Tidal Zone

Journal of the Society of Materials Science Japan ◽

10.2472/jsms.65.162 ◽

2016 ◽

Vol 65 (2) ◽

pp. 162-169

Author(s):

Kyohei SHIMURA ◽

Takahiro NISHIDA ◽

Kenichiro IMAFUKU ◽

Nobuaki OTSUKI

Keyword(s):

Cathodic Protection ◽

Coated Steel ◽

Tidal Zone

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Cathodic Protection Analysis of Spools With GRP Cover

Volume 5B: Pipelines, Risers, and Subsea Systems ◽

10.1115/omae2017-61277 ◽

2017 ◽

Author(s):

Randi B. Kongstein ◽

Rannveig Kvande

Keyword(s):

Cathodic Protection ◽

Steel Surface ◽

Ionic Current ◽

Comsol Multiphysics ◽

The Finite Element Method ◽

Large Current ◽

Bare Steel ◽

Glass Fibre Reinforced ◽

Current Lines ◽

Subsea Pipelines

Cathodic protection (CP) design of pipelines is generally described in internationally recognized standards and recommended practices. However, not all cases can be solved by conventional CP calculations as recommended approaches and methods may not be fully defined in the standards. For instance, Glass fibre Reinforced Polyester (GRP) covers can be applied for mechanical protection (e.g. from trawl and/or dropped object) of subsea pipelines and structures. These GRP covers will restrict the electrical/ionic current lines between the anode and the steel surface to be cathodically protected. For a spool with in-line components requiring a large current (e.g. painted or bare steel) and with a GRP cover it may be difficult to obtain sufficient cathodic protection when applying simple mathematical calculations. This paper describes how the Finite Element Method (FEM) in COMSOL Multiphysics can be applied to show that the potential is acceptable for such cases.

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The beneficial secondary effects of conventional and pulse cathodic protection for reinforced concrete, evidenced by X-ray and microscopic analysis of the steel surface and the steel/cement paste interface

Materials and Corrosion ◽

10.1002/maco.200805155 ◽

2009 ◽

Vol 60 (9) ◽

pp. 704-715 ◽

Cited By ~ 10

Author(s):

D. A. Koleva ◽

Z. Guo ◽

K. van Breugel ◽

J. H. W. de Wit

Keyword(s):

Reinforced Concrete ◽

Cement Paste ◽

Cathodic Protection ◽

Steel Surface ◽

Microscopic Analysis ◽

Secondary Effects ◽

X Ray

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Corrosion and cathodic protection of carbon steel in the tidal zone: Products, mechanisms and kinetics

Corrosion Science ◽

10.1016/j.corsci.2014.10.035 ◽

2015 ◽

Vol 90 ◽

pp. 375-382 ◽

Cited By ~ 60

Author(s):

Ph. Refait ◽

M. Jeannin ◽

R. Sabot ◽

H. Antony ◽

S. Pineau

Keyword(s):

Carbon Steel ◽

Cathodic Protection ◽

Tidal Zone

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Experimental research of shipbuilding steels at cathodic polarization

MORSKIE INTELLEKTUAL`NYE TEHNOLOGII ◽

10.37220/mit.2020.49.3.009 ◽

2020 ◽

Author(s):

А.В. Родькина ◽

О.А. Иванова ◽

В.А. Крамарь ◽

В.Р. Душко

Keyword(s):

Oxide Film ◽

Cathodic Protection ◽

Steel Surface ◽

Cathodic Polarization ◽

Mechanical Damage ◽

Applied Current ◽

Electrostatic Adsorption ◽

Rebinder Effect ◽

Anions And Cations ◽

Marine Vessels

С целью определения корректных значений защитного потенциала, указываемых в системах катодной защиты морских судов и сооружений наложенным током для предотвращения локальных коррозионно-механических разрушений разработана методика определения потенциала корпусных сталей в отсутствии поверхностной пленки при катодной поляризации. Полученные значения потенциала могут быть рекомендованы для использования как защитного в системах катодной защиты, обеспечивая потенциал незаряженной поверхности стали, в том числе и на поверхности без оксидной пленки. В результате происходит подавление процесса адсорбции анионов и катионов; предотвращение процесса растрескивания стали; стабилизация процесса катодной поляризации при потенциале незаряженной поверхности, когда на поверхности стали заторможена электростатическая адсорбция и не наблюдается эффект Ребиндера. In order to determine the correct values of the protective potential indicated in the cathodic protection of marine vessels and structures by applied current to prevent local corrosion and mechanical damage, a method has been developed for determining the potential of hull steels during cathodic polarization on a surface without an oxide film. The obtained potential values can be recommended for use as protective in cathodic protection, providing the potential of an uncharged steel surface, including on a surface without an oxide film. As a result, the process of anions and cations adsorption is suppressed; prevention of steel cracking; stabilization of the cathodic polarization process at the potential of an uncharged surface, when electrostatic adsorption is inhibited on the steel surface and the Rebinder effect is not observed.

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Study of Overprotective-Polarization of Steel Subjected to Cathodic Protection in Unsaturated Soil

Materials ◽

10.3390/ma14154123 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4123

Author(s):

Mandlenkosi G. R. Mahlobo ◽

Peter A. Olubambi ◽

Phumlani Mjwana ◽

Marc Jeannin ◽

Philippe Refait

Keyword(s):

Raman Spectroscopy ◽

Corrosion Rate ◽

Cathodic Protection ◽

Steel Surface ◽

Open Circuit Potential ◽

Protective Layer ◽

Progressive Increase ◽

Open Circuit ◽

Applied Potential ◽

Protective Ability

Various electrochemical methods were used to understand the behavior of steel buried in unsaturated artificial soil in the presence of cathodic protection (CP) applied at polarization levels corresponding to correct CP or overprotection. Carbon steel coupons were buried for 90 days, and the steel/electrolyte interface was studied at various exposure times. The coupons remained at open circuit potential (OCP) for the first seven days before CP was applied at potentials of −1.0 and −1.2 V vs. Cu/CuSO4 for the remaining 83 days. Voltammetry revealed that the corrosion rate decreased from ~330 µm yr−1 at OCP to ~7 µm yr−1 for an applied potential of −1.0 V vs. Cu/CuSO4. CP effectiveness increased with time due to the formation of a protective layer on the steel surface. Raman spectroscopy revealed that this layer mainly consisted of magnetite. EIS confirmed the progressive increase of the protective ability of the magnetite-rich layer. At −1.2 V vs. Cu/CuSO4, the residual corrosion rate of steel fluctuated between 8 and 15 µm yr−1. EIS indicated that the protective ability of the magnetite-rich layer deteriorated after day 63. As water reduction proved significant at this potential, it is proposed that the released H2 bubbles damage the protective layer.

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EELS characterization of “Smut” layer films on steel surface prepared for chrome plating by anodic etching

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100139068 ◽

1995 ◽

Vol 53 ◽

pp. 538-539

Author(s):

E Y. Wang ◽

J. T. Cherian ◽

A. Madsen ◽

R. M. Fisher

Keyword(s):

Steel Surface ◽

Surface Preparation ◽

Treatment Method ◽

Chrome Plating ◽

Transmission Electron ◽

Alloy Steels ◽

Pre Treatment ◽

Hard Chrome ◽

Electron Energy Loss

Many steel parts are electro-plated with chromium to protect them against corrosion and to improve their wear-resistance. Good adhesion of the chrome plate to the steel surface, which is essential for long term durability of the part, is extremely dependent on surface preparation prior to plating. Recently, McDonnell Douglas developed a new pre-treatment method for chrome plating in which the steel is anodically etched in a sulfuric acid and hydrofluoric acid solution. On carbon steel surfaces, this anodic pre-treatment produces a dark, loosely adhering material that is commonly called the “smut” layer. On stainless steels and nickel alloys, the surface is only darkened by the anodic pre-treatment and little residue is produced. Anodic pre-treatment prior to hard chrome plating results in much better adherence to both carbon and alloy steels.We have characterized the anodic pre-treated steel surface and the resulting “smut” layer using various techniques including electron spectroscopy for chemical analysis (ESCA) on bulk samples and transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS) on stripped films.

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