Studies on corrosion of surface-treated aluminum alloys in sea water

Abstract Aluminum alloys 3003, 3004, and 5050 were evaluated for desalination applications by means of their anodic polarization curves determined in 1X synthetic sea water at 25 C (77 F) to 150 C (302 F). Pitting performance was established from the relative values of the corrosion potential and the breakdown and protection potentials, and general corrosion rates were calculated from corrosion currents determined by the slop-intercept method. Pitting is not anticipated for 3003 and 3004 alloys at temperatures to 150 C and for 5050 alloy to 125 C (257 F). General corrosion rates for these alloys were less than 1 mpy.

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A Polyaniline Coating Material for Inhibiting Corrosion in Marine Environment

MRS Proceedings ◽

10.1557/proc-598-bb5.8 ◽

1999 ◽

Vol 598 ◽

Author(s):

Yuan Lin ◽

Sze C. Yang ◽

Robert Clark ◽

Richard Brown

Keyword(s):

Aluminum Alloys ◽

Marine Environment ◽

Sea Water ◽

Metal Corrosion ◽

Epoxy Primer ◽

Doped Polyaniline ◽

Polymeric Complexes ◽

Pre Treatment ◽

Chromate Replacement ◽

Protection Of Metals

ABSTRACTThe conventional molecular ion doped polyaniline undergoes dedoping in sea water because the sea water, with pH = 8, induces deprotontation of polyaniline. In this article we report polyaniline complexes that remain conductive in sea water. These complexes are useful for corrosion protection of metals in marine environment and for chromate replacement coatings. The reason for the pH stability of these polyaniline complexes was discussed. The polymeric complexes of polyaniline were used as an additive in an epoxy primer coating on AL7075-T6 without surface pre-treatment of the metal. Corrosion tests show that these polymeric complexes of polyaniline are effective for improving the corrosion inhibition in seawater for aluminum alloys.

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Galvanic Corrosion of Aluminum

CORROSION ◽

10.5006/0010-9312-35.9.423 ◽

1979 ◽

Vol 35 (9) ◽

pp. 423-428 ◽

Cited By ~ 19

Author(s):

M. C. REBOUL

Keyword(s):

Stainless Steel ◽

Aluminum Alloys ◽

Sea Water ◽

Galvanic Corrosion ◽

Tap Water ◽

Field Tests ◽

Electrochemical Characteristics ◽

Galvanic Current ◽

Galvanic Couples ◽

The Cost

Abstract Laboratory tests were carried out to compare the electrochemical characteristics of galvanic couples made of aluminum alloys (1050, 5086, 2024, and 7075) with other metals (plain steel, Type 316 stainless steel, titanium) in tap water and in artificial sea water. It was found that: One must first choose materials which individually resist corrosion. Only when this requirement is fulfilled can the risk of galvanic corrosion be evaluated. In aluminum-steel assemblies, taking into account only the risk of galvanic corrosion leads to the following bad choices: (1) the choice of copper containing aluminum alloys which are less anodic than copper free alloys (poor choice except when justified by mechanical factors),and (2) the choice of plain steel which is less noble than stainless steel. Although they generate weaker galvanic currents, field tests show that those assemblies made of corrosive materials have shorter life than stainless steel assembled with a copper free aluminum alloy. The galvanic current produced by the couple decreases rapidly with time, then stabilizes within a few days. The comparison of these stabilized currents seems to be the best way to compare the risks of galvanic corrosion. For a given couple of different metals, the life span of the assembly depends upon the conductivity and the aggressiveness of the environment; in other words the complexity and the cost of the protection to be used, for a given couple increase with the aggressiveness of the environment.

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REVISITING THE CONFIRMATION OF THE IDENTITY OF THE CORROSION DESTRUCTION MECHANISM OF ALUMINUM ALLOYS (review) Part 2. Corrosion in sea water

Aviation Materials and Technologies ◽

10.18577/2713-0193-2021-0-1-95-103 ◽

2021 ◽

pp. 95-103

Author(s):

M.G. Abramova ◽

Keyword(s):

Aluminum Alloys ◽

Sea Water ◽

Chemical Parameters ◽

Destruction Mechanism ◽

Physical And Chemical Parameters ◽

Main Factors ◽

Fouling Organisms ◽

Physical And Chemical ◽

Test Objects

The paper presents an overview of studies of the corrosion destruction mechanisms of aluminum alloys in seawater. The main factors that have the greatest impact on corrosion are considered: physical and chemical parameters, the depth of the test objects, as well as the role of biofouling. It has been determined that the parameter of the species composition of the fouling organisms is an important factor in the corrosion of metals in seawater and should be taken into account when identifying the mechanism of corrosion destruction during tests under various conditions.

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Corrosion properties of amg3 aluminum alloy treated by short-pulse plasma electrolytic oxidation in marine conditions

MORSKIE INTELLEKTUAL`NYE TEHNOLOGII ◽

10.37220/mit.2021.54.4.041 ◽

2021 ◽

pp. 117-121

Author(s):

В.С. Егоркин ◽

И.Е. Вялый ◽

Н.В. Изотов ◽

А.Н. Минаев ◽

С.Л. Синебрюхов ◽

...

Keyword(s):

Aluminum Alloy ◽

Aluminum Alloys ◽

Plasma Electrolytic Oxidation ◽

Sea Water ◽

Protective Coatings ◽

Short Pulse ◽

Salt Spray ◽

Corrosion Properties ◽

Electrolytic Oxidation ◽

Plasma Electrolytic

Алюминиевые сплавы находят все более широкое применение в морской технике как для строительства корпусов судов, так и для изготовления различного судового оборудования, трубопроводов и других устройств. Однако применение алюминиевых сплавов в элементах морской техники, подвергающихся прямому контакту с морской водой или работающих в условиях морской атмосферы, требует дополнительного изучения и разработки мер по улучшению антикоррозионных свойств. Формирование защитных покрытий на поверхности алюминиевых сплавов методом плазменного электролитического оксидирования (ПЭО) позволяет повысить антикоррозионные характеристики. В работе представлены результаты комплексных исследований коррозионной стойкости и морфологии ПЭО-покрытий, сформированных на алюминиевом сплаве АМг3, в камере соляного тумана и при натурных испытаниях в морской воде и в морской атмосфере. Показано, что обработка алюминиевого сплава АМг3 методом плазменного электролитического оксидирования с использованием короткоимпульсного поляризующего сигнала приводит к улучшению коррозионных характеристик формируемого покрытия. Aluminum alloys are increasingly used in marine engineering both for the construction of ship hulls and for the manufacture of various ship equipment, pipelines and other devices. However, the use of aluminum alloys in elements of marine technology exposed to direct contact with sea water or operating in the sea atmosphere requires additional study and development of ways to improve anticorrosion properties. The formation of protective coatings on the surface of aluminum alloys by the method of plasma electrolytic oxidation (PEO) enable one to increase the anticorrosive characteristics. The paper presents the results of comprehensive studies of the corrosion resistance and morphology of PEO coatings formed on the AMg3 aluminum alloy in a salt spray chamber and during field tests in sea water and in the marine atmosphere. It is shown that the treatment of the AMg3 aluminum alloy by the method of plasma electrolytic oxidation with the use of a short-pulse polarizing signal leads to an improvement in the corrosion characteristics of the formed coating.

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Analytical Electron Microscopy Study of Second-Phase Particles in 7075 and 7475 Aluminum Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100118618 ◽

1985 ◽

Vol 43 ◽

pp. 348-349

Author(s):

M. Raghavan ◽

J. Y. Koo ◽

J. W. Steeds ◽

B. K. Park

Keyword(s):

Aluminum Alloys ◽

Silicon Oxide ◽

Analytical Electron Microscopy ◽

Microscopy Study ◽

Electron Microscopy Study ◽

Partial Substitution ◽

Second Phase ◽

X Ray ◽

Second Phase Particles ◽

Almost All

X-ray microanalysis and Convergent Beam Electron Diffraction (CBD) studies were conducted to characterize the second phase particles in two commercial aluminum alloys -- 7075 and 7475. The second phase particles studied were large (approximately 2-5μm) constituent phases and relatively fine ( ∼ 0.05-1μn) dispersoid particles, Figures 1A and B. Based on the crystal structure and chemical composition analyses, the constituent phases found in these alloys were identified to be Al7Cu2Fe, (Al,Cu)6(Fe,Cu), α-Al12Fe3Si, Mg2Si, amorphous silicon oxide and the modified 6Fe compounds, in decreasing order of abundance. The results of quantitative X-ray microanalysis of all the constituent phases are listed in Table I. The data show that, in almost all the phases, partial substitution of alloying elements occurred resulting in small deviations from the published stoichiometric compositions of the binary and ternary compounds.

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