Copper enrichment on Al 2024 surface after de-oxidizing treatment

1993 ◽  
Vol 51 ◽  
pp. 860-861
Author(s):  
C. A. Drewien ◽  
R. G. Buchheit ◽  
K. R. Zavadil ◽  
T. E. Neil
Keyword(s):  
Aluminum Alloys ◽  
Salt Spray ◽  
Lithium Carbonate ◽  
Salt Spray Test ◽  
Lithium Aluminum ◽  
General Corrosion ◽  
Corrosion Properties ◽  
Carbonate Hydroxide ◽  
Processing Step ◽  
Aluminum Part

Coatings of lithium-aluminum-carbonate-hydroxide are being developed for corrosion protection of aluminum alloys against atmospheric and saline environments. Coating is performed by immersion of the aluminum part into a lithium carbonate-lithium hydroxide solution of pH=11.5. Before coating, the aluminum alloy is degreased in trichloroethylene, cleaned in a sodium carbonate-sodium silicate bath, and de-oxidized in nitric acid containing ammonium biflouride. Coating of most aluminum alloys is easily accomplished, and the coatings pass the ASTM B117 salt spray test. However, aluminum alloys that contain copper, specifically 2024-T3 and 7075-T6, yield coatings that fail the salt spray test, i.e. pitting and general corrosion is observed. Photographs of coatings after 168 hr salt spray exposure are shown in Figure 1 for Al 1100 and 2024-T3 alloys. A study has been undertaken to determine the influence of copper upon the corrosion properties of the coating.The surface of 2024-T3 was analyzed after each processing step in order to determine if copper enrichment at the specimen surface was occurring.

Influence of Formation Conditions on Corrosion Behavior of PEO-Coatings during Salt-Spray Test

2020 ◽  
Vol 312 ◽  
pp. 319-324
Author(s):  
Vladimir S. Egorkin ◽  
Igor E. Vyaliy ◽  
Andrey S. Gnedenkov ◽  
Nikolay V. Izotov ◽  
Dmitry K. Tolkanov ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Salt Spray ◽  
Protective Layer ◽  
Salt Spray Test ◽  
Corrosion Properties ◽  
Sem Image ◽  
Formation Conditions ◽  
Aluminum Alloy 2024 ◽  
Plasma Electrolytic ◽  
Peo Coatings

Plasma electrolytic oxidation (PEO) was used to form a protective layer on 5754 and 2024 aluminum alloys to improve the corrosion properties of the processed materials. The protective performances of the obtained coatings were studied by a combination of electrochemical methods and salt spray test. The absence of pitting corrosion after a 7-day test for the entire series of PEO-layers on aluminum alloys 5754 and 2024 was confirmed by scanning electron microscopy (SEM). Also, microcracks were detected only in the SEM-image for the most porous and thin PEO-coating formed on aluminum alloy 2024 at duty cycle = 0.06 and 30 min.

Lithium-aluminum-carbonate-hydroxide hydrate coatings on aluminum alloys: Composition, structure, and processing bath chemistry

1996 ◽  
Vol 11 (6) ◽  
pp. 1507-1513 ◽  
Author(s):  
C.A. Drewien ◽  
M. O. Eatough ◽  
D. R. Tallant ◽  
C. R. Hills ◽  
R. G. Buchheit
Keyword(s):  
Crystal Structure ◽  
Aluminum Alloys ◽  
Bulk Material ◽  
Lithium Carbonate ◽  
Lithium Aluminum ◽  
Nominal Composition ◽  
Al Alloy ◽  
Carbonate Hydroxide ◽  
Coating Formation ◽  
Composition Structure

A new corrosion resistant coating, being designed for possible replacement of chromate conversion coatings on aluminum alloys, was investigated for composition, structure, and solubility using a variety of techniques. The stoichiometry of the material, prepared by immersion of 1100 Al alloy into a lithium carbonate-lithium hydroxide solution, was approximately Li2Al4CO3(OH)12 · 3H2O. Processing time was shown to be dependent upon the bath pH, and consistent coating formation required supersaturation of the coating bath with aluminum. The exact crystal structure of this hydrotalcite material, hexagonal or monoclinic, was not determined. It was shown that both the bulk material and coatings with the same nominal composition and crystal structure could be formed by precipitation from an aluminum supersatured solution of lithium carbonate.

Investigation on dual corrosion performance of magnesium-rich primer for aluminum alloys under salt spray test (ASTM B117) and natural exposure

2010 ◽  
Vol 52 (4) ◽  
pp. 1453-1463 ◽  
Author(s):  
Shashi S. Pathak ◽  
Michael D. Blanton ◽  
Sharathkumar K. Mendon ◽  
James W. Rawlins
Keyword(s):  
Aluminum Alloys ◽  
Salt Spray ◽  
Salt Spray Test ◽  
Corrosion Performance ◽  
Natural Exposure

Analysis of Mixtures of Gamma Lithium Aluminate, Lithium Aluminum Carbonate Hydroxide Hydrate, and Lithium Carbonate

1997 ◽  
Vol 496 ◽  
Author(s):  
M. T. Nemeth ◽  
R. B. Ford ◽  
T. A. Taylor
Keyword(s):  
Ceramic Powder ◽  
Lithium Carbonate ◽  
Lithium Aluminum ◽  
Carbonate Content ◽  
Lithium Aluminate ◽  
Molten Carbonate ◽  
X Ray Diffraction ◽  
Carbonate Hydroxide ◽  
Molten Carbonate Fuel Cells ◽  
Hydroxide Hydrate

ABSTRACTLithium aluminate, LiA1O2is a ceramic powder which is used as the porous solid support for the electrolyte in molten carbonate fuel cells (MCFCs). It has previously been reported that gamma LiAlO2will convert to lithium aluminum carbonate hydroxide hydrate, Li2Al4(CO3)(OH)123H2O and Li2CO3when exposed to water vapor and carbon dioxide. We compare three techniques, weight gain, carbonate content and x-ray diffraction to measure the amount of conversion. The reaction may involve amorphous intermediates and no one technique by itself is satisfactory to study the conversion.

scholarly journals Corrosion Behavior during Cyclic Salt Spray Test of Friction Stir Welded A7075 and A6N01 Aluminum Alloys

2006 ◽  
Vol 70 (1) ◽  
pp. 96-105 ◽  
Author(s):  
Xiaoyong Yun ◽  
Yoshinobu Motohashi ◽  
Tsutomu Ito ◽  
Toshiyuki Asano ◽  
Satoshi Hirano
Keyword(s):  
Aluminum Alloys ◽  
Corrosion Behavior ◽  
Salt Spray ◽  
Salt Spray Test ◽  
Friction Stir

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

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.

Effects of Conductive Pigments on the Anti-Corrosion Properties of Zinc-Rich Coatings

2013 ◽  
Vol 652-654 ◽  
pp. 1830-1833
Author(s):  
Ling Chen ◽  
Xue Jiao Zheng ◽  
Hui Ma ◽  
Jia Qing Wang
Keyword(s):  
Aluminum Powder ◽  
Salt Spray ◽  
Zinc Content ◽  
Graphite Powder ◽  
Immersion Test ◽  
Open Circuit ◽  
Salt Spray Test ◽  
Content Increase ◽  
Corrosion Properties ◽  
Iron Phosphide

Effects of replacing partial zinc dust with conductive pigments on the anti-corrosion properties of ethyl silicate zinc-rich coatings with low zinc content were investigated. Salt spray test, salt immersion test and open circuit potential(OCP) measurement were utilized to evaluate anti-corrosion properties. Experimental results revealed that the effects of conductive pigments content on anti-corrosion properties are similar for di-iron phosphide powder, graphite powder and aluminum powder employed in this article. For every kind of conductive pigments, protection life in salt spray test, protection life in salt immersion test, galvanic protection life and initial OCP change with conductive pigments content increase in a similar way. They all reach an extreme point, and all the extreme points correspond to a same replacing ratio named best replacing ratio. The best replacing ratio is 20,15 and 15wt% for di-iron phosphide powder, graphite powder and aluminum powder respectively. Comparing with non-replacing coatings, conductive pigments-containing coatings at best replacing ratio possess both lower zinc content and better anti-corrosion properties.

Electrochemical Impedance Characteristics of Sintered 7075 Aluminum Alloy Under Ssrt Condition

2013 ◽  
Vol 58 (2) ◽  
pp. 505-508 ◽  
Author(s):  
S. Sunada ◽  
N. Nunomura
Keyword(s):  
Aluminum Alloys ◽  
Complex Shape ◽  
Electrochemical Impedance ◽  
Ingot Metallurgy ◽  
View Point ◽  
Corrosion Properties ◽  
Electrochemical Tests ◽  
Impedance Characteristics ◽  
Polarization Test ◽  
Conventional Ingot

Powder metallurgy (P/M) process has the advantage of better formability to fabricate complex shape products without machining and welding. And recently this P/M process has been applied to the production of aluminum alloys. The P/M aluminum alloys thus produced also have received considerable interest because of their fine and homogeneous structure. Many papers have been published on the mechanical properties of the aluminum alloys produced by P/M process while there have been few on their corrosion properties from the view point of electrochemistry. In this experiment, therefore, two kinds of 7075 aluminum alloys prepared by the conventional ingot metallurgy (I/M) process and P/M process were used, I/M material is commercially available. and their corrosion behavior were investigated through the electrochemical tests such as potentiodynamic polarization test, slow rate strain tensile (SSRT) test and electrochemical impedance spectroscopy (EIS) measurement under SSRT test in the corrosion solution and the deionized water.

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