US20080029401A1 - Process for Forming Anticorrosive Coating - Google Patents

Process for Forming Anticorrosive Coating Download PDF

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Publication number
US20080029401A1
US20080029401A1 US11/547,475 US54747505A US2008029401A1 US 20080029401 A1 US20080029401 A1 US 20080029401A1 US 54747505 A US54747505 A US 54747505A US 2008029401 A1 US2008029401 A1 US 2008029401A1
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United States
Prior art keywords
coating
steel structure
anticorrosive coating
seawater
magnesium hydrate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
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US11/547,475
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English (en)
Inventor
Kenichi Akamine
Yasunobu Suzuki
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IHI Corp
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IHI Corp
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Filing date
Publication date
Application filed by IHI Corp filed Critical IHI Corp
Assigned to ISHIKAWAJIMA-HARIMA HEAVY INDUSTRIES CO., LTD. reassignment ISHIKAWAJIMA-HARIMA HEAVY INDUSTRIES CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: AKAMINE, KENICHI, SUZUKI, YASUNOBU
Publication of US20080029401A1 publication Critical patent/US20080029401A1/en
Abandoned legal-status Critical Current

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    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/22—Piles
    • E02D5/64—Repairing piles
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D9/00—Electrolytic coating other than with metals
    • C25D9/04—Electrolytic coating other than with metals with inorganic materials
    • C25D9/08—Electrolytic coating other than with metals with inorganic materials by cathodic processes
    • C25D9/10—Electrolytic coating other than with metals with inorganic materials by cathodic processes on iron or steel
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F2213/00—Aspects of inhibiting corrosion of metals by anodic or cathodic protection
    • C23F2213/30—Anodic or cathodic protection specially adapted for a specific object
    • C23F2213/31—Immersed structures, e.g. submarine structures

Definitions

  • the present invention relates to a process for forming anticorrosive coating and more specifically to a process for forming anticorrosive coating on a marine steel structure in a short period.
  • a process for anticorrosion of a marine steel structure has been proposed in which the steel structure is used as a cathode, an anode being arranged in seawater to be opposed to the steel structure. Direct current is passed between the electrodes to form coating (anticorrosive coating) on the steel structure through electrolytic reaction of the seawater, thereby attaining anticorrosion of the steel structure.
  • Reference 1 discloses that a steel member constituting a surface of a marine steel structure is used as a cathode, an anode being arranged in seawater to be opposed to the steel member. Direct current is passed between the electrodes to remove rust and the like scales on the surface of the steel structure. Then, direct current is passed between the electrodes to deposit electrodeposit, which has electrolytic reaction product of the seawater as dominant constituent, on the surface and any corroded pores of the steel structure, thereby forming anticorrosive coating.
  • the coating formed as mentioned above on the marine steel structure through electrolytic reaction of the seawater has calcium carbonate CaCO 3 and magnesium hydrate Mg(OH) 2 as main components.
  • CaCO 3 calcium carbonate formed hard in hardness that exhibits anticorrosive effect. Therefore, in order to make a marine steel structure anticorrosive, anticorrosive coating having calcium carbonate as dominating component must be formed on the steel structure.
  • composition ratio of calcium carbonate in the coating is high and that of magnesium hydrate is low.
  • composition ratio of calcium carbonate is decreased and that of magnesium hydrate is increased. It is regarded that good anticorrosion property is obtained when coating composition ratio of calcium carbonate to magnesium hydrate is 1 or more.
  • the conventional process for forming anticorrosive coating as disclosed in Reference 1 requires long construction period and long-term management and is costly due to increased electric power consumption, so that the process has not been practically applied except special cases such as bridge piers at sites in deep water or in violent tidal current.
  • the invention was made in view of the above and has its object to provide a process for forming anticorrosive coating which can be conducted cheaply in a short period, thereby easily leading to general application to marine steel structures.
  • the invention is directed to a process for forming anticorrosive coating on a marine steel structure wherein the steel structure is used as a cathode, an anode being arranged in seawater to be opposed to said steel structure, direct current being passed between the electrodes, anticorrosive coating being formed on the steel structure through electrolytic reaction of the seawater, thereby attaining anticorrosion of the marine steel structure, characterized by passing the electric current between the electrodes so as to have current density to form coating having magnesium hydrate as dominant constituent on said marine steel structure, thereby forming the coating with a predetermined thickness, then stopping supply of the electric current to thereby provide anticorrosive coating through compositional substitution effect which occurs in the presence of the seawater to substitute calcium carbonate for the magnesium hydrate.
  • the electric current is passed between the electrodes so as to attain current density of the marine steel structure in a range of 3 to 10 A/m 2 .
  • a process for forming anticorrosive coating of the invention electric current is passed between electrodes so as to keep high current density of a marine steel structure, so that coating with magnesium hydrate as dominant constituent is formed on the steel structure in a short period. Then, supply of the electric current is stopped to utilize a compositional substitution effect which occurs in the presence of the seawater to substitute calcium carbonate for the magnesium hydrate, thereby forming anticorrosive coating.
  • the invention has an effect that it can form good anticorrosive coating with calcium carbonate as dominant constituent in by far a shorter period than ever before.
  • the invention has an effect that it can be easily applicable to any kind of marine steel structures unlike the conventional process with limited applicability to special sites.
  • FIG. 1 A diagram showing relationship between coating composition on a marine steel structure and current density due to electric current applied between electrodes.
  • FIG. 2 A side view exemplifying equipment components in application of a process for forming anticorrosive coating according to the invention to a steel caisson of a breakwater which is an example of a marine steel structure.
  • FIG. 3 A front view looking in the direction of arrows III in FIG. 2 .
  • FIG. 4 A diagram showing test results of generated amount of calcium carbonate.
  • FIG. 5 A diagram showing test results of generated amount of magnesium hydrate.
  • FIG. 6 A view showing coating generated on a cathode substrate in the test equipment.
  • FIG. 7 A view showing change of the coating in FIG. 5 into anticorrosive coating through compositional substitution effect.
  • FIG. 8 A diagram showing variation in composition ratio of magnesium hydrate and calcium carbonate by stopping supply of electric current after formation of coating with magnesium hydrate as dominant constituent.
  • FIG. 9 A diagram showing variation of the coating amount on a mol basis.
  • FIG. 10 A diagram showing variation of the coating amount on a weight basis.
  • FIG. 2 is a side view exemplifying equipment components in application of a process for forming anticorrosive coating according to the invention to a steel caisson of a breakwater which is an example of a marine steel structure; and FIG. 3 , a front view looking in the direction of arrows III in FIG. 2 .
  • reference numeral 1 denotes steel caissons which constitute a breakwater; 2 , a DC power supply on arranged for example on a top of the steel caisson 1 ; and 3 , undersea members suspended in seawater to be opposed in a predetermined distance to the submerged surface of the steel caisson 1 and spaced from each other by a predetermined distance and in parallel with the surface of the steel caisson 1 .
  • the undersea members 3 may be made from soluble material such as magnesium or aluminum or insoluble material such as titanium.
  • the DC power supply 2 is connected at its minus ( ⁇ ) side to the steel caisson 1 so as to use the steel caisson 1 as a cathode and is connected at its plus (+) side to the undersea member 3 so as to use the undersea member 3 as an anode.
  • Such construction is made to each of the plural steel caissons 1 .
  • a predetermined constant current is passed between the electrodes, i.e., between the steel caisson 1 and the undersea member 3 by the DC power supply 2 , so that deposited coating is formed on the steel caisson 1 through electrolytic reaction of the seawater.
  • monitoring electrodes 4 are arranged at plural points on the submerged surface of each steel caisson 1 , a monitoring unit 5 being arranged for example on the top of the steel caisson 1 so as to determine and display electric potential from detected values of the respective monitoring electrodes 4 .
  • the monitoring unit 5 severs for checking that electric current with a predetermined current density is passed through the steel caisson 1 through application of constant electric current on the steel caisson 1 by the DC power supply 2 .
  • the monitoring unit 5 may have the function of a controller for automatically controlling the voltage of the DC power supply 2 so as to keep the detected electric potential to be a predetermined constant potential.
  • FIG. 4 shows the fact that, as the current density is increased, the generated amount calcium carbonate is rapidly increased into its peak with the current density being 0.5 A/m 2 or so; as the current density is further increased, then the generated amount of calcium carbonate tends to be rapidly decreased.
  • FIG. 5 shows the fact that, as the current density is increased up to about 7 A/m 2 , the generated amount of magnesium hydrate is increased toward its peak; as the current density is further increased, then the generated amount of magnesium hydrate tends to be decreased.
  • FIG. 5 The data shown in FIG. 5 are those in laboratory experiment with still water condition, so that in actual sea areas, electrodeposition efficiency may be lowered due to effect of tidal current (see, for example, Honshi-Giho Vol. 24, No. 95 (December 2000)).
  • tidal current see, for example, Honshi-Giho Vol. 24, No. 95 (December 2000)
  • tests were conducted with respect to generated amount of coating in real sea areas to find out that an optimum range of current density in real sea areas is 3 to 10 A/m 2 .
  • the coating formed on the steel caisson 1 has magnesium hydrate as dominant constituent (for example, 95% of magnesium hydrate), failing to be anticorrosive coating.
  • the inventors made researches so as to change the coating with magnesium hydrate as dominant constituent and formed in a short period as mentioned above into anticorrosive coating with calcium carbonate as dominant constituent and found out that compositional substitution effect occurs in seawater to substitute calcium carbonate for the magnesium hydrate, thereby utilizing such effect to attain formation of anticorrosive coating.
  • the inventors used experimental equipment similar to that shown in FIGS. 2 and 3 to conduct tests for forming coating so as to ascertain the above-mentioned compositional substitution effect.
  • cathode substrate in opposed relationship to the steel caisson 1 is made from SS (stainless steel) 400 and the anode member corresponding to the undersea member 3 is made from Mg, using natural seawater with temperature of 25° C. with the current applying condition of current density being 3 A/m 2 .
  • coating test for 30 hours was conducted.
  • thickness L of the coating 7 generated on the cathode substrate 6 in the test was detected to be 105 ⁇ m.
  • the composition obtained in chemical analysis of the coating 7 was, as shown in FIG. 8 , about 5% of calcium carbonate and about 95% of magnesium hydrate, most of the composition being magnesium hydrate.
  • reaction formula (1) occurs to bring about the reaction formula (2), leading to the reaction formula (3).
  • the coating 7 with magnesium hydrate as dominant constituent as shown in FIG. 6 is replaced by calcium carbonate through the above-mentioned compositional substitution effect to thereby form, as shown in FIG. 7 , the hard anticorrosive coating having calcium carbonate as dominant constituent with no substantial change in thickness L.
  • the electric current applying condition was the current density of 3 A/m 2 . That is, the experiments were conducted with lower current density since the coating tends to fall off in the case of the experimental equipment with no flows of seawater. However, it turned out that in actual natural seawater with flows, coating can be formed well with no falling-off even if the process is conducted with the current density of as high as 3 to 10 A/m 2 .
  • anticorrosive coating according to the invention can be formed in a very short period on the order of one month or one month and a half. This facilitates the process management and brings about reduction in electricity consumption, resulting in decrease in cost. Therefore, with no limitation to the special sites unlike the conventional process, the invention can be easily applied to any kinds of marine steel structures.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Structural Engineering (AREA)
  • Electrochemistry (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mining & Mineral Resources (AREA)
  • Paleontology (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Prevention Of Electric Corrosion (AREA)
  • Preventing Corrosion Or Incrustation Of Metals (AREA)
US11/547,475 2004-05-11 2005-04-28 Process for Forming Anticorrosive Coating Abandoned US20080029401A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2004-140715 2004-05-11
JP2004140715A JP4424059B2 (ja) 2004-05-11 2004-05-11 防食膜形成方法
PCT/JP2005/008133 WO2005108645A1 (fr) 2004-05-11 2005-04-28 Procede d’elaboration d’un revetement anticorrosion

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US20080029401A1 true US20080029401A1 (en) 2008-02-07

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US11/547,475 Abandoned US20080029401A1 (en) 2004-05-11 2005-04-28 Process for Forming Anticorrosive Coating

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US (1) US20080029401A1 (fr)
EP (1) EP1770188A4 (fr)
JP (1) JP4424059B2 (fr)
NO (1) NO20065301L (fr)
WO (1) WO2005108645A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3031347A1 (fr) * 2015-01-06 2016-07-08 Electricite De France Protection cathodique d'une structure metallique creuse, contre la corrosion
JP2019163505A (ja) * 2018-03-20 2019-09-26 株式会社Ihi 水中金属構造物の防食電着被膜形成方法

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4217245B2 (ja) * 2006-01-20 2009-01-28 株式会社神戸製鋼所 耐水素脆性に優れた高強度鋼
JP5434237B2 (ja) * 2009-04-28 2014-03-05 株式会社Ｉｈｉ 防食析出膜の維持方法及び維持装置
JP5387280B2 (ja) * 2009-09-25 2014-01-15 株式会社Ｉｈｉ 電着被膜形成装置
JP5387356B2 (ja) * 2009-11-24 2014-01-15 株式会社Ｉｈｉ 海洋鋼構造物の防食電着被膜施工方法及び装置
JP5740845B2 (ja) * 2010-06-01 2015-07-01 株式会社Ihi 海洋鋼構造物の防食方法
JP5740851B2 (ja) * 2010-06-23 2015-07-01 株式会社Ihi 鋼矢板の電着防食装置
JP5678505B2 (ja) * 2010-07-26 2015-03-04 株式会社Ihi 有潮流海域での海洋鋼構造物の防食被膜形成方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4246075A (en) * 1979-03-19 1981-01-20 Marine Resources Company Mineral accretion of large surface structures, building components and elements
US20040262164A1 (en) * 2003-06-25 2004-12-30 Sang-Hun Han Method and apparatus for managing plating interruptions

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61261499A (ja) * 1985-05-13 1986-11-19 Mitsui Eng & Shipbuild Co Ltd 電着装置
JP3000411B2 (ja) * 1992-08-19 2000-01-17 三井造船株式会社 鉄筋コンクリート構造物のひび割れ箇所の早期診断方法及び補修方法
JPH10313728A (ja) * 1997-05-20 1998-12-02 Honsyu Shikoku Renrakukiyou Kodan 海洋鉄鋼構造物の防食方法
JP4126513B2 (ja) * 1998-08-19 2008-07-30 株式会社Ｉｈｉ エレクトロコーティングによる防汚方法および防汚装置
JP4131055B2 (ja) * 1999-06-04 2008-08-13 株式会社Ｉｈｉ エレクトロコーティングによるいけす金網の防汚方法

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4246075A (en) * 1979-03-19 1981-01-20 Marine Resources Company Mineral accretion of large surface structures, building components and elements
US20040262164A1 (en) * 2003-06-25 2004-12-30 Sang-Hun Han Method and apparatus for managing plating interruptions

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3031347A1 (fr) * 2015-01-06 2016-07-08 Electricite De France Protection cathodique d'une structure metallique creuse, contre la corrosion
JP2019163505A (ja) * 2018-03-20 2019-09-26 株式会社Ihi 水中金属構造物の防食電着被膜形成方法
JP7066465B2 (ja) 2018-03-20 2022-05-13 株式会社Ihi 水中金属構造物の防食電着被膜形成方法

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Publication number Publication date
EP1770188A4 (fr) 2008-07-23
NO20065301L (no) 2006-11-17
JP2005320602A (ja) 2005-11-17
JP4424059B2 (ja) 2010-03-03
WO2005108645A1 (fr) 2005-11-17
EP1770188A1 (fr) 2007-04-04

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Owner name: ISHIKAWAJIMA-HARIMA HEAVY INDUSTRIES CO., LTD., JA

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Effective date: 20060914

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