US20170145581A1 - Method of treating surface of aluminum substrate to increase performance of offshore equipment - Google Patents

Method of treating surface of aluminum substrate to increase performance of offshore equipment Download PDF

Info

Publication number
US20170145581A1
US20170145581A1 US15/149,400 US201615149400A US2017145581A1 US 20170145581 A1 US20170145581 A1 US 20170145581A1 US 201615149400 A US201615149400 A US 201615149400A US 2017145581 A1 US2017145581 A1 US 2017145581A1
Authority
US
United States
Prior art keywords
aluminum substrate
corrosion inhibitor
oxide film
corrosion
substrate
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
Application number
US15/149,400
Other languages
English (en)
Inventor
Jung-Yeul Jung
Tae-Kyeong Yeu
Sup Hong
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Korea Institute of Ocean Science and Technology KIOST
Original Assignee
Korea Institute of Ocean Science and Technology KIOST
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Korea Institute of Ocean Science and Technology KIOST filed Critical Korea Institute of Ocean Science and Technology KIOST
Assigned to KOREA INSTITUTE OF OCEAN SCIENCE & TECHNOLOGY reassignment KOREA INSTITUTE OF OCEAN SCIENCE & TECHNOLOGY ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HONG, SUP, JUNG, JUNG-YEUL, YEU, Tae-Kyeong
Publication of US20170145581A1 publication Critical patent/US20170145581A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/18—After-treatment, e.g. pore-sealing
    • C25D11/24—Chemical after-treatment
    • 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
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C26/00—Coating not provided for in groups C23C2/00 - C23C24/00
    • 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
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/04—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in markedly acid liquids
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon

Definitions

  • the present invention relates to a method of treating the surface of an aluminum substrate to increase the performance of offshore equipment.
  • offshore equipment for use in fabricating ships and large marine structures is mainly manufactured using alloys and other metal elements.
  • the use of non-iron metals is increasing these days in order to realize offshore equipment exhibiting high durability and lightweightness.
  • the surface of the aluminum substrate therefor is treated using a variety of methods to prevent the corrosion thereof.
  • Metal corrosion means that the properties of metal change through chemical or electrochemical reaction of the metal with materials contained in the ambient environment. Typically, metal corrosion occurs due to the presence of electrolytes such as soil, fresh water or seawater, the presence of cathode-anode potential difference, or the presence of a conductor for connecting a cathode and an anode. Also, metal corrosion is classified into dry corrosion, in the absence of water, and wet corrosion, in the presence of water, and takes place while corrosion current flows from the anode to the cathode due to a partial potential difference depending on the material and environment. In order to prevent the corrosion of the metal substrate, at least one corrosion factor, such as an electrolyte, a potential difference or a conductor, has to be eliminated.
  • metal corrosion cannot be actually completely prevented, the metal is inhibited from corroding in a manner of alleviating the corrosion or by suppressing corrosion to some extent for a predetermined time.
  • Known methods for preventing corrosion include a surface treatment process through coating of the surface of a metal substrate with a corrosion inhibitor and an electron-chemical protection process for allowing predetermined potential to flow to the metal substrate to thus induce a kind of battery reaction.
  • Recently useful is a surface treatment process for treating the surface of the metal substrate through coating with a corrosion inhibitor or the like.
  • the corrosion inhibitor includes asphalt, wax, petroleum and lubricating base oil, and is applied on the surface of a metal substrate to form a coating layer, in order to achieve an effect of physically protecting the surface of the metal substrate using physical strength and a chemical protection effect for preventing corrosive material such as oxygen or water from contacting the surface of the metal substrate through the interfacial action of the corrosion inhibitor, such as adsorption, solubilization, neutralization, dispersion or water substitution.
  • the coating layer on the surface of the metal substrate, formed through the coating process with the corrosion inhibitor is lost over time, and thus the surface of the metal substrate corrodes.
  • the coating with the corrosion inhibitor has to be repeated in order to form the coating layer on the surface of the metal substrate.
  • the metal substrate including aluminum and an aluminum alloy widely useful as a non-iron metal in deep seawater offshore equipment, has been used by being coated with a corrosion inhibitor in order to prevent the corrosion thereof.
  • an object of the present invention is to provide a method of treating the surface of an aluminum substrate in order to increase corrosion resistance and anti-fouling effects of offshore equipment.
  • the present invention provides a method of treating a surface of an aluminum substrate, comprising: (a) forming a porous oxide film on the surface of the aluminum substrate; and (b) applying a corrosion inhibitor on the surface of the aluminum substrate having the oxide film formed thereon.
  • the aluminum substrate may include Al7075.
  • (a) may be performed using an anodizing process or a plasma electrolytic oxidation process.
  • the anodizing process may be performed at room temperature at a voltage of 30 to 100 V for 1 to 3 hr.
  • the oxide film may be formed at a thickness of 10 to 20 ⁇ m on the surface of the aluminum substrate.
  • the corrosion inhibitor may be an oil-type corrosion inhibitor.
  • the corrosion inhibitor may further include a viscosity controller.
  • (b) may be performed using any one process selected from among spray coating, screen printing, brushing, and dipping.
  • (b) may further include homogenizing the surface of the aluminum substrate, after the applying the corrosion inhibitor on the surface of the aluminum substrate having the oxide film formed thereon.
  • the present invention provides an aluminum substrate for offshore equipment, manufactured by the above method.
  • the method of treating the surface of an aluminum substrate enables the formation of a porous oxide film on the surface of the aluminum substrate through surface treatment so that the applied corrosion inhibitor is partially absorbed into the porous oxide film, thus exhibiting superior corrosion resistance and anti-fouling effects of a metal substrate, compared to conventional surface treatment methods involving coating only with a corrosion inhibitor.
  • FIG. 1A is a field emission scanning electron microscope (FE-SEM) image illustrating the surface of the anodized aluminum substrate according to the present invention
  • FIG. 1B is an enlarged FE-SEM image of FIG. 1A ;
  • FIG. 2 is of actual images illustrating changes in the surface of the anodized aluminum substrate after dropping treatment of an oil-type corrosion inhibitor, a solvent dilution-type corrosion inhibitor, a semisolid-type corrosion inhibitor and water according to the present invention.
  • FIG. 3 is a graph illustrating the corrosion susceptibility of the surface-treated aluminum substrates in the example and comparative example.
  • the present invention addresses a method of treating the surface of an aluminum substrate, comprising: (a) forming a porous oxide film on the surface of the aluminum substrate and (b) applying a corrosion inhibitor on the surface of the aluminum substrate having the oxide film formed thereon.
  • (a) is a step of forming a porous oxide film on the surface of the aluminum substrate.
  • the aluminum substrate may be used without limitation so long as it has any composition typically used in the art.
  • Preferably useful is Al7075, which is an aluminum alloy comprising aluminum, magnesium, copper or zinc to thus exhibit superior mechanical properties and high usefulness in offshore equipment.
  • an aluminum substrate which is desmutted through degreasing treatment using any commercially available aluminum degreasing agent, etching treatment, and surface treatment with an acid, may be used such that the porous oxide film is formed on the surface thereof.
  • the formation of the porous oxide film on the surface of the aluminum substrate may be implemented through anodizing treatment or plasma electrolytic oxidation.
  • the surface of the aluminum substrate is oxidized due to oxygen generated at the anode under the condition that the aluminum substrate is used as the anode and electricity is allowed to flow in the electrolyte, thereby obtaining a dense yet porous alumina film having superior mechanical properties.
  • the plurality of pores, which are formed in the surface of the aluminum substrate, are dependent on the temperature and voltage in the anodizing process, and the average pore size increases in proportion to an increase in the temperature and voltage.
  • the thickness of the oxide film, which is formed on the surface of the aluminum substrate depends on the temperature and voltage in the anodizing process, and the film thickness increases in proportion to an increase in the temperature and voltage.
  • the surface of the aluminum substrate may be anodized under various temperature and voltage conditions, thus forming the porous oxide film having an average pore size suitable for end use as the aluminum substrate and a thickness able to maintain sufficient strength.
  • the oxide film is preferably formed to a thickness of 10 to 20 ⁇ m on the surface of the aluminum substrate, and is provided in the form of a porous oxide film having an average pore size of 30 to 100 nm, thereby facilitating the absorption of the corrosion inhibitor that is to be applied in the subsequent procedure.
  • the surface of the aluminum substrate is anodized at 10 to 30° C. at a voltage of 30 to 100 V for 1 to 3 hr, whereby the porous oxide film having a uniform pore size is formed on the surface of the aluminum substrate.
  • the oxide film formed on the surface of the aluminum substrate is too thin.
  • the above temperature is higher than 30° C., the current density applied to the pores formed in the surface of the aluminum substrate is further increased, and thus the pores are continuously grown in a direction perpendicular to the surface of the aluminum substrate, undesirably increasing the thickness of the oxide film.
  • the anodizing process is preferably carried out.
  • the anodizing process is preferably carried out.
  • anodizing treatment is carried out at 25° C. at 40 V for 3 hr, whereby the porous oxide film having a uniform pore size is formed on the surface of the aluminum substrate.
  • (b) is a step of applying the corrosion inhibitor on the surface of the aluminum substrate having the porous oxide film formed thereon.
  • the corrosion inhibitor particularly a non-aqueous corrosion inhibitor is applied on the surface of the aluminum substrate having the porous oxide film formed thereon and is thus absorbed through the pores of the porous oxide film, thereby forming a coating layer having improved corrosion resistance and anti-fouling efficiency.
  • the corrosion inhibitor may be an oil-type corrosion inhibitor that includes a petroleum-based solvent.
  • the oil-type corrosion inhibitor may be obtained in a manner in which an environmentally friendly metal salt having high corrosion resistance and heat resistance, such as silicon, silver, magnesium, vanadium, zirconium, titanium, or hafnium, is alkalized with sodium hydroxide, potassium hydroxide or a mixture thereof and then mixed with a petroleum-based solvent or organic synthetic oil, thereby maximizing the corrosion resistance and anti-fouling effects of the surface-treated aluminum substrate.
  • an environmentally friendly metal salt having high corrosion resistance and heat resistance such as silicon, silver, magnesium, vanadium, zirconium, titanium, or hafnium
  • a petroleum-based solvent or organic synthetic oil thereby maximizing the corrosion resistance and anti-fouling effects of the surface-treated aluminum substrate.
  • a variety of known lubricating corrosion inhibitors such as NP-7, NP-8, NP-9 and NP-10, may be used.
  • the oil-type corrosion inhibitor preferably has a viscosity of 1 to 1000 cP.
  • the corrosion inhibitor When the corrosion inhibitor having the viscosity within the above range is applied on the surface of the aluminum substrate, the corrosion inhibitor is provided in the form of a coating layer at a thickness of 10 ⁇ m or more on the surface of the aluminum substrate while being absorbed into the pores of the oxide film.
  • the oil-type corrosion inhibitor is further mixed with a viscosity controller so as to adjust the degree of absorption of the corrosion inhibitor into the pores in the porous oxide film formed on the surface of the aluminum substrate, thereby controlling the absorption efficiency and thickness of the coating layer.
  • the corrosion inhibitor coating layer which is formed while being absorbed into the micropores in the oxide film, may exhibit superior corrosion resistance and anti-fouling effects because the retention time of the corrosion inhibitor on the surface of the aluminum substrate is increased and thus corrosion resistance and breakdown potential are increased, compared to aluminum substrates obtained through conventional surface treatment methods using only a corrosion inhibitor coating process.
  • the surface of the aluminum substrate is coated with the corrosion inhibitor using a process such as spray coating, screen printing, brushing or dipping.
  • the present step may further comprise homogenizing the surface of the aluminum substrate, after applying the corrosion inhibitor on the surface of the aluminum substrate having the oxide film formed thereon.
  • the homogenizing treatment is performed in a manner such that the coating layer is uniformly diffused in the oxide film using a variety of known metal surface heat-treatment processes on the surface of the aluminum substrate having the coating layer formed thereon, thereby forming the coating layer at a uniform thickness on the surface of the aluminum substrate.
  • the corrosion inhibitor coating layer is formed while being absorbed into the micropores in the oxide film, the retention time thereof on the surface of the aluminum substrate is increased, thus increasing corrosion resistance and breakdown potential, ultimately exhibiting superior corrosion resistance and anti-fouling effects, compared to aluminum substrates obtained through conventional surface treatment methods using only a corrosion inhibitor coating process.
  • the method of treating the surface of the aluminum substrate according to the present invention enables the corrosion resistance and anti-fouling effects of offshore equipment, which is constantly exposed to seawater and marine conditions, to be increased, thus enhancing the performance of offshore equipment utilized in ships or marine plants, whereby economical industrial effects can be expected.
  • the aluminum substrate was disposed as an anode in an electrolyte containing 0.3 M oxalic acid and sulfuric acid, and the aluminum substrate was subjected to anodizing treatment at 25° C. at a voltage of 40 V for 3 hr.
  • the surface of the anodized aluminum substrate was observed using FE-SEM. The results are shown in FIGS. 1A and 1B .
  • the anodized aluminum substrate was confirmed to have the porous oxide film layer formed thereon.
  • each of a non-aqueous corrosion inhibitor oil-type
  • NP-1 solvent dilution-type
  • anti-corrosive petrolactam semisolid-type
  • water H 2 O
  • the aluminum substrate onto which the solvent dilution-type corrosion inhibitor was dropped a portion of the solvent dilution-type corrosion inhibitor was absorbed into the oxide film layer.
  • the corrosion inhibitor was not significantly absorbed.
  • the oil-type corrosion inhibitor manifested the greatest adsorption properties for coating of the aluminum substrate.
  • a non-aqueous corrosion inhibitor was sprayed onto one surface of the anodized aluminum substrate using a spray coating process, thus forming the coating layer on the surface of the aluminum substrate, whereby the surface of the aluminum substrate was subjected to corrosion resistance and anti-fouling treatment.
  • the surface of an aluminum substrate was subjected to corrosion resistance and anti-fouling treatment in the same manner as in the above example, with the exception that anodizing treatment was not performed.
  • the oil-type corrosion inhibitor was applied while being absorbed into the oxide film on the surface of the aluminum substrate, thus inducing metal oxidation at a higher potential. Furthermore, the breakdown potential of the aluminum substrate was higher than that of the aluminum substrate that was surface-treated using the method of Comparative Example. Therefore, when the aluminum substrate having the oxide film formed using the method of Example was coated with the corrosion inhibitor, the corrosion resistance and anti-fouling efficiency of the aluminum substrate were increased.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Mechanical Engineering (AREA)
  • General Chemical & Material Sciences (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)
US15/149,400 2015-11-23 2016-05-09 Method of treating surface of aluminum substrate to increase performance of offshore equipment Abandoned US20170145581A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR2015-0164257 2015-11-23
KR1020150164257A KR101643575B1 (ko) 2015-11-23 2015-11-23 해양기자재의 성능향상을 위한 알루미늄 기재의 표면 처리 방법

Publications (1)

Publication Number Publication Date
US20170145581A1 true US20170145581A1 (en) 2017-05-25

Family

ID=56681822

Family Applications (1)

Application Number Title Priority Date Filing Date
US15/149,400 Abandoned US20170145581A1 (en) 2015-11-23 2016-05-09 Method of treating surface of aluminum substrate to increase performance of offshore equipment

Country Status (2)

Country Link
US (1) US20170145581A1 (ko)
KR (1) KR101643575B1 (ko)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101859527B1 (ko) * 2016-11-29 2018-06-28 한국해양과학기술원 내식성능 향상을 위한 알루미늄의 화학적 표면개질 방법 및 이에 의해 표면개질한 알루미늄 소재
KR20190064045A (ko) 2017-11-30 2019-06-10 한국해양과학기술원 해양기자재의 내식/방오 성능 향상을 위한 나노입자 스프레이 코팅 기반 금속 기재 표면 코팅 방법
KR20190080219A (ko) 2017-12-28 2019-07-08 (주)브이티엠 우수한 내식성 및 경량성을 가지는 해상 cctv 하우징용 복합소재 제조방법 및 이에 의해 제조된 해상 cctv 하우징용 복합소재

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1297688C (zh) * 2000-05-30 2007-01-31 杰富意钢铁株式会社 具有有机涂层的钢板和其制造方法
JP3784638B2 (ja) 2000-11-24 2006-06-14 株式会社日鉱マテリアルズ 金属表面処理剤およびそれを塗布した金属材料
KR100825620B1 (ko) * 2006-06-22 2008-04-25 주식회사 포스코 제조성이 우수한 내후성강용 방청 피막 도료 및 그 제조방법
JP5451965B2 (ja) 2007-01-29 2014-03-26 株式会社神戸製鋼所 アルミニウム合金用表面処理剤
EP2210970B1 (en) * 2007-10-25 2017-03-29 Mitsubishi Rayon Co., Ltd. Stamper, process for producing the same, process for producing molding, and aluminum base die for stamper
WO2010112605A1 (en) 2009-04-03 2010-10-07 Akzo Nobel Coatings International B.V. Anti-corrosive coating composition
KR101301210B1 (ko) 2011-03-31 2013-09-10 (주)디포유건업 철재표면을 수분산성의 세라믹도료로 표면처리하는 방법
KR20130048554A (ko) * 2011-11-02 2013-05-10 (주)엔에스엔 아연도금재의 방청 코팅 조성물

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
McDermott et al US 2010/0252241 A1 *

Also Published As

Publication number Publication date
KR101643575B1 (ko) 2016-07-28

Similar Documents

Publication Publication Date Title
Ivanou et al. Plasma anodized ZE41 magnesium alloy sealed with hybrid epoxy-silane coating
JP6383803B2 (ja) 陽極酸化処理された材料の腐食を防止するための組成物及び方法
Chung et al. Effect of current density and concentration on microstructure and corrosion behavior of 6061 Al alloy in sulfuric acid
Barchiche et al. A better understanding of PEO on Mg alloys by using a simple galvanostatic electrical regime in a KOH–KF–Na3PO4 electrolyte
TW200408010A (en) Halogen-resistant, anodized aluminum for use in semiconductor processing apparatus
Song et al. Corrosion resistance of water repellent aluminum surfaces with various wetting morphologies
Balan et al. Modified silane films for corrosion protection of mild steel
US20170145581A1 (en) Method of treating surface of aluminum substrate to increase performance of offshore equipment
Raj et al. Comparative study of formation and corrosion performance of porous alumina and ceramic nanorods formed in different electrolytes by anodization
Lee et al. Essential anti-corrosive behavior of anodized Al alloy by applied current density
WO2016178372A1 (ja) 耐食皮膜を有する積層体とその製造方法
RU2543580C1 (ru) Способ получения защитных покрытий на сплавах магния
JP5614671B2 (ja) 酸化被膜及びその形成方法
Konno et al. Corrosion protection of iron using porous anodic oxide/conducting polymer composite coatings
Sidorova et al. Effect of PEO-modes on the electrochemical and mechanical properties of coatings on MA8 magnesium alloy
Kim et al. Influence of ZrO2 incorporation into coating layer on electrochemical response of low-carbon steel processed by electrochemical plasma coating
Telmenbayar et al. Fabrication of a superhydrophobic surface on Al alloy 5052 via combined anodic oxidation and fluorination treatment
Mazhari Abbasi et al. Optimizing the TiO2 content to obtain the highest corrosion resistance in Ir-Ru-Ta-based mixed metal oxide coating in oxygen evolution reaction application
KR101859527B1 (ko) 내식성능 향상을 위한 알루미늄의 화학적 표면개질 방법 및 이에 의해 표면개질한 알루미늄 소재
Liu et al. Electrodeposition of polypyrrole films on 2024 aluminum alloy in phosphoric acid solution
Naief et al. Comparative Study for Anodizing Aluminum Alloy 1060 by Different Types of Electrolytes Solutions
CN111344836B (zh) 耐腐蚀性及绝缘特性优秀的阳极氧化包含铝的构件及其的氧化膜形成方法
Senbahavalli et al. Enhanced corrosion resistance of anodic non-porous alumina (ANPA) coatings on aluminium fabricated from mixed organic-inorganic electrolytes
Jin-Young et al. Influence of potassium pyrophosphate in electrolyte on coated layer of AZ91 Mg alloy formed by plasma electrolytic oxidation
Mashtalyar et al. Formation of the composite coatings as a method of restoration of titanium products after exploitation

Legal Events

Date Code Title Description
AS Assignment

Owner name: KOREA INSTITUTE OF OCEAN SCIENCE & TECHNOLOGY, KOR

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:JUNG, JUNG-YEUL;YEU, TAE-KYEONG;HONG, SUP;REEL/FRAME:038635/0098

Effective date: 20160516

STPP Information on status: patent application and granting procedure in general

Free format text: NON FINAL ACTION MAILED

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION