scholarly journals Corrosion Resistance of Hard Coat Anodized AA 6061 in Citric–Sulfuric Solutions

Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 601
Author(s):  
José Cabral-Miramontes ◽  
Citlalli Gaona-Tiburcio ◽  
Francisco Estupinán-López ◽  
María Lara-Banda ◽  
Patricia Zambrano-Robledo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Sulfuric Acid Electrolyte ◽  
Cyclic Potentiodynamic Polarization ◽  
Anodization Process ◽  
Current Densities ◽  
Corrosive Environments ◽  
Sulfuric Acid Solutions

Aluminum is a material widely used in aeronautical and transport industries due to its excellent mechanical and corrosion resistance properties. Unfortunately, aluminum alloys are susceptible to corrosion, which limits their use in some corrosive environments. The aim of this work is to characterize hard coat film fabricated by anodizing in a citric–sulfuric acid system using electrochemical techniques. The anodization process was carried out using an aluminum alloy AA 6061 anodization bath: a mix of citric and sulfuric acid solutions were used. For the anodizing process, two current densities were used, 1 and 7.2 A·cm−2. Anodized specimens obtained under different conditions were exposed to a 3.5 wt.% NaCl solution, and their electrochemical behavior was studied by electrochemical impedance spectroscopy (EIS) and cyclic potentiodynamic polarization (CPP) according to ASTM G106-15 and ASTM G5-13, respectively. Scanning electron microscopy (SEM) was employed to determinate the morphology and thickness of coatings. The results showed improved corrosion resistance in 6061 aluminum anodized in citric–sulfuric acid electrolyte compared to those anodized in sulfuric acid solution.

scholarly journals Corrosion and Corrosion Inhibition of High Strength Low Alloy Steel in 2.0 M Sulfuric Acid Solutions by 3-Amino-1,2,3-triazole as a Corrosion Inhibitor

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
El-Sayed M. Sherif ◽  
Adel Taha Abbas ◽  
D. Gopi ◽  
A. M. El-Shamy
Keyword(s):  
Sulfuric Acid ◽  
Corrosion Inhibition ◽  
Polarization Resistance ◽  
Immersion Time ◽  
Electrochemical Impedance ◽  
Hsla Steel ◽  
Electrochemical Techniques ◽  
High Strength ◽  
X Ray ◽  
Sulfuric Acid Solutions

The corrosion and corrosion inhibition of high strength low alloy (HSLA) steel after 10 min and 60 min immersion in 2.0 M H2SO4solution by 3-amino-1,2,4-triazole (ATA) were reported. Several electrochemical techniques along with scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) were employed. Electrochemical impedance spectroscopy indicated that the increase of immersion time from 10 min to 60 min significantly decreased both the solution and polarization resistance for the steel in the sulfuric acid solution. The increase of immersion time increased the anodic, cathodic, and corrosion currents, while it decreased the polarization resistance as indicated by the potentiodynamic polarization measurements. The addition of 1.0 mM ATA remarkably decreased the corrosion of the steel and this effect was found to increase with increasing its concentration to 5.0 mM. SEM and EDS investigations confirmed that the inhibition of the HSLA steel in the 2.0 M H2SO4solutions is achieved via the adsorption of the ATA molecules onto the steel protecting its surface from being dissolved easily.

scholarly journals A New Approach in Modifying Polymeric Coatings to Increase Corrosion Resistance Properties

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Alisina Toloei ◽  
Sanam Atashin ◽  
Mohammad Ebrahim Bahrololoom
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Open Circuit ◽  
Polymeric Coatings ◽  
Protective Properties ◽  
Clay Nanoparticles ◽  
Steel Sheets ◽  
Corrosive Environments ◽  
Modified Epoxy

In this study, carbon steel sheets were coated with a modified epoxy coating. The urea-modified montmorillonite clay nanoparticles were added to a DGEBA epoxy resin in different contents and then applied to the surfaces. The corrosion resistance of the coated samples was determined by electrochemical techniques (open circuit potential and linear polarization) in 3.5 wt% NaCl solutions at room temperature and 80°C. Electrochemical impedance spectroscopy (EIS) evaluated the properties of polymer-coated metals and their changes during the exposure to corrosive environments. Scanning electron microscopy (SEM) was used to characterize the coatings. An improvement of protective properties of epoxy coatings with an optimal percentage of the modified clay in comparison with pure epoxy was achieved.

Corrosion and Corrosion Inhibition of Aluminum Alloys A5052 and A5754 in Sulfuric Acid Solutions by Some Inorganic Inhibitors

2017 ◽  
Vol 231 (6) ◽  
Author(s):  
S.S. Abd El-Rehim ◽  
M.A. Deyab ◽  
H.H. Hassan ◽  
Ahamed Abd El-Moneim
Keyword(s):  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Aluminum Alloys ◽  
Electrochemical Impedance ◽  
Pure Aluminum ◽  
Solution Temperature ◽  
Acid Solutions ◽  
X Ray ◽  
Potentiodynamic Polarization Curves ◽  
Sulfuric Acid Solutions

AbstractThe corrosion of aluminum alloys (A5052 and 5754) in sulfuric acid solutions was investigated using potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), and energy-dispersive X-ray (EDX) methods. For comparison, the corrosion of pure aluminum in sulfuric acid was examined potentiodynamically. The data reveal that increasing sulfuric acid concentrations and solution temperature enhance the corrosion rate of aluminum alloys. The two aluminum alloys exhibit higher corrosion resistance than pure aluminum. Moreover, A5052 involves more corrosion resistance than A5754. The effect of WO

scholarly journals Corrosion Behavior of AA 1100 Anodized in Gallic-Sulfuric Acid Solution

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 405
Author(s):  
Marlon L. Mopon ◽  
Jayson S. Garcia ◽  
Dexter M. Manguerra ◽  
Cyril John C. Narisma
Keyword(s):  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Acid Solution ◽  
Gallic Acid ◽  
Acid Concentration ◽  
Sulfuric Acid Solution ◽  
Current Density ◽  
Electrochemical Impedance ◽  
Anodized Aluminum ◽  
The Common

Sulfuric acid anodization is one of the common methods used to improve corrosion resistance of aluminum alloys. Organic acids can be added to the sulfuric acid electrolyte in order to improve the properties of the anodized aluminum produced. In this study, the use of gallic acid as an additive to the sulfuric acid anodization of AA1100 was explored. The effect of varying anodization current density and gallic acid concentration on the properties of anodized aluminum samples was observed using electrochemical impedance spectroscopy, linear polarization, and scanning electron microscopy. It was observed that the corrosion resistance of samples anodized in gallic-sulfuric acid solution at 10 mA·cm−2 is lower than samples anodized in sulfuric acid. It was also observed that higher anodization current density can lead to lower corrosion resistances for aluminum samples anodized in gallic-sulfuric acid solution. However, samples anodized at 5 mA·cm−2 and at a gallic acid concentration of 5 g·L−1 showed better corrosion performance than the samples anodized in sulfuric acid only. This suggests that the use of low amounts of gallic acid as an additive for sulfuric acid anodization can lead to better corrosion resistances for anodized aluminum.

scholarly journals ESTUDIO DE LA RESISTENCIA A LA CORROSION DEL ALUMINIO 6063 ANODIZADO

2017 ◽  
Vol 22 (2) ◽  
pp. 17
Author(s):  
Karín Paucar Cuba ◽  
Hugo Rojas Flores ◽  
Abel Vergara Sotomayor
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Sulfuric Acid ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Aluminum Surface ◽  
Equivalent Circuits ◽  
Acid Salt ◽  
Mass Losses ◽  
Palabras Clave

El estudio de la resistencia a la corrosión del anodizado de una aleación de aluminio (AA6063) en ácido sulfúrico a diferentes tiempos de anodizado: 30, 45 y 60 min. se realizó usando la espectroscopia de impedancia electroquímica (EIE) y el ensayo de niebla salina ácida. (ASTM B287). Los datos obtenidos por EIE y su correlación con los circuitos equivalentes más apropiados permitieron determinar los parámetros asociados a la capa porosa y a la capa barrera del óxido protector formado sobre la superficie del aluminio en estudio. La exposición de las muestras anodizadas durante 250h a una niebla salina ácida permitió observar variaciones en su masa. De los resultados obtenidos por EIE y las pérdidas de masa de las muestras anodizadas se estableció que la película de anodizado de 45 minutos mostró una mayor resistencia a la corrosión en comparación con la obtenida a 60 y 30 min., respectivamente. Palabras clave.- Aluminio, Anodizado, Impedancia electroquímica, Niebla salina ácida. ABSTRACTThe study of the corrosion resistance of anodized on aluminum alloy (AA6063) in sulfuric acid to different times: 30, 45 and 60 min. was performed using electrochemical impedance spectroscopy (EIS) and the acid salt spray test (ASTM B287). The EIS’data and its correlation with the most appropriate equivalent circuits allowed to determine the parameters associated with the porous layer and the oxide layer protective barrier formed on the aluminum surface under study. Exposure of the samples anodized for a 250h salt spray acid allowed to observe changes in their mass. From the results obtained by EIS and the mass losses of the anodized samples was established that the anodized film of 45 minutes showed higher corrosion resistance compared to that obtained at 60 and 30 min, respectively. Keywords.- Aluminum, Anodized, Electrochemical impedance, Acid salt spray.

Corrosion Resistance of Nd-Fe-B Magnets Coated with Polypyrrole Films

2006 ◽  
Vol 530-531 ◽  
pp. 111-116
Author(s):  
M.C.E. Bandeira ◽  
F.D. Prochnow ◽  
Isolda Costa ◽  
César V. Franco
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Nacl Solution ◽  
Corrosion Performance ◽  
Low Frequencies ◽  
Polypyrrole Films ◽  
Phosphate Ions ◽  
Polypyrrole Film ◽  
Corrosive Environments ◽  
Magnet Surface

Nd-Fe-B magnets present outstanding magnetic properties. However, due to their low corrosion resistance, their applications are limited to non-corrosive environments. Nowadays, significant efforts are underway to increase the corrosion resistance of these materials, through the use of coatings. Herein are presented the results of a study on the corrosion resistance of Nd-Fe-B magnets coated with polypyrrole (PPY). The electrochemical behavior of coated and uncoated magnets has been studied by Electrochemical Impedance spectroscopy (EIS) in synthetic saliva. The results were compared to previous investigations, which were carried out under similar conditions, in Na2SO4 and NaCl solutions. In sulphate solution, the corrosion resistance of the PPY-coated magnet was 3 times larger (1600 .cm2) than that of uncoated magnet (500 .cm2). In NaCl solution, however, the corrosion resistance of coated and uncoated magnets were very similar (250 .cm2). In synthetic saliva, both the uncoated and coated magnets presented good corrosion performance (1940 .cm2). Such behavior can be attributed to the phosphate ions in saliva, which play a role as corrosion inhibitor, producing phosphating, at least partially, of the magnet surface. The PPY-coated magnets presented a strong diffusional control from moderate to low frequencies, caused by the polypyrrole film. The thicker PPY film increased the corrosion resistance of the magnet in synthetic saliva.

Improved Corrosion Resistance and Increased Hardness of Copper Substrates from Cu-Ni/Ni-P Composite Coatings

MRS Advances ◽  
2020 ◽  
Vol 5 (40-41) ◽  
pp. 2129-2137 ◽  
Author(s):  
Wenwen Dou ◽  
Wen Li ◽  
Yuchen Cai ◽  
Mengyao Dong ◽  
Xiaojing Wang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Copper Substrate ◽  
Electrolytic Deposition ◽  
Deposition Method ◽  
Nacl Solution ◽  
Current Densities ◽  
Superior Corrosion Resistance ◽  
Deposition Conditions

ABSTRACTTo improve the corrosion resistance and to increase the hardness of copper substrate in marine environment, the Cu-Ni/Ni-P composite coatings were prepared on the copper substrate using the galvanostatic electrolytic deposition method. The deposition current densities were explored to find the optimized deposition conditions for forming the composite coatings. Corrosion resistance properties were analyzed using the polarization curves and electrochemical impedance spectroscopy (EIS). Considering the corrosion resistance and hardness, the −20 mA/cm2 was selected to deposit Cu-Ni coatings on copper substrate and the −30 mA/cm2 was selected to deposit Ni-P coating on the Cu-Ni layer. The Cu-Ni/Ni-P composite coatings not only exhibited superior corrosion resistance compared to single Cu-Ni coating in 3.5 wt.% NaCl solution, but also showed much better mechanical properties than single Cu-Ni coating.

MICROSTRUCTURE AND ELECTROCHEMICAL PROPERTIES OF Ni–B/GO ULTRASONIC-ASSISTED COMPOSITE COATINGS

2019 ◽  
Vol 26 (10) ◽  
pp. 1950080
Author(s):  
JIBO JIANG ◽  
HAOTIAN CHEN ◽  
LIYING ZHU ◽  
YAOXIN SUN ◽  
WEI QIAN ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Ultrasonic Field ◽  
Protective Material ◽  
X Ray ◽  
Electrochemical Tests ◽  
Ultrasonic Assisted ◽  
Corrosive Environments

Graphene oxide (GO) sheet and ultrasonic field (UF) were successfully employed to produce Ni–B/GO and UF–Ni–B/GO composite coatings on Q235 mild steel by electroless plating. The composite coatings’ structure and surface morphology were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Results showed that GO was successfully co-deposited in the Ni–B alloy. Moreover, UF–Ni–B/GO composite coatings have smoother surface and thicker cross-section than others. The microhardness and corrosion resistance of the sample coatings were determined using Vickers hardness tests, Tafel electrochemical tests and electrochemical impedance measurements (EIS) in 3.5[Formula: see text]wt.% NaCl solution to receive the effect of GO and ultrasonic. The findings indicated that UF–Ni–B/GO exhibited optimum hardness (856[Formula: see text]HV) and enhanced corrosion resistance (6.38 [Formula: see text][Formula: see text] over the Ni–B and Ni–B/GO coatings. Due to these interesting properties of the coating, it could be used as a protective material in the automotive and aerospace industries for parts of machines that were manipulated in high temperature and corrosive environments.

scholarly journals Evaluation of the Corrosion Resistance of Phosphate Coatings Deposited on the Surface of the Carbon Steel Used for Carabiners Manufacturing

2020 ◽  
Vol 10 (8) ◽  
pp. 2753 ◽  
Author(s):  
Diana-Petronela Burduhos-Nergis ◽  
Petrica Vizureanu ◽  
Andrei Victor Sandu ◽  
Costica Bejinariu
Keyword(s):  
Corrosion Resistance ◽  
Carbon Steel ◽  
Zinc Phosphate ◽  
Sea Water ◽  
Electrochemical Impedance ◽  
Phosphate Solution ◽  
Fire Extinguishing ◽  
Different Types ◽  
Iron Based ◽  
Corrosive Environments

This study aims to evaluate the corrosion resistance of carbon steel, used for carabiners manufacturing, coated with three different types of phosphate layer. The phosphate layers have been obtained by phosphate conversion coating with three different types of phosphate solutions: zinc-based solution, zinc-iron-based phosphate solution, and manganese-based phosphate solution. Additionally, the test was performed on zinc phosphate samples impregnated with molybdenum bisulfate-based oil and zinc phosphate samples further coated with a layer of elastomer-based paint. Considering the areas where the carabiners are used (civil engineering, navigation, oil industry, rescue operations, etc.), the corrosive environments studied are rainwater, Black Sea water, and fire extinguishing solution. The structure of the deposited layers was studied by scanning electron microscopy, while the interface structure between the alloy and corrosive environment was analyzed by electrochemical impedance spectroscopy. According to this study, the corrosion resistance of zinc-based phosphate coated samples and zinc/iron-based phosphate coated samples is higher than that of the studied carbon steel samples, despite the corrosion environment. Also, the most aggressive corrosion environment was the fire extinguishing solution.

Electrochemical Investigation of the Effects of Acid Concentration and Dissolved Oxygen on the Corrosion Behavior of Austenitic Low-Nickel Stainless Steels in Citric Acid

2016 ◽  
Vol 835 ◽  
pp. 115-120
Author(s):  
Francis Mulimbayan ◽  
Manolo G. Mena
Keyword(s):  
Corrosion Resistance ◽  
Citric Acid ◽  
Dissolved Oxygen ◽  
Corrosion Behavior ◽  
Polarization Resistance ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Open Circuit ◽  
Human Consumption ◽  
Face Centered Cubic

All materials which are intended to have in contact with food and other commodities produced or processed for human consumption are called food contact materials (FCM’s). Stainless steel (SS) – a widely known metallic FCM is used mainly in processing equipment, containers and household utensils. It is known for having numerous industrial and domestic applications worldwide due to its special characteristics of having notable corrosion resistance. However, this corrosion resistance is not all-encompassing since SS may still undergo degradation when subjected to a specific corrosion-inducing environment. SS may be classified according to its microstructure. If the atoms which make up the SS can be viewed as having a face-centered cubic structure, then the alloy is said to be austenitic. This SS grades include the conventional 300-series and the newly-developed 200-series. The former has superior corrosion resistance while the latter is far cheaper. In this study, the corrosion behavior of AISI 202 SS in two different levels of dissolved oxygen (O2) and three acid concentrations was investigated using electrochemical techniques, namely, open-circuit potential (OCP) measurements and electrochemical impedance spectroscopy (EIS). As the concentration of citric acid is increased, the measured OCP values of the alloy decreased and the polarization resistance (Rp) decreased, indicating decrease in alloy stability and decline in the corrosion resistance, respectively. With regards to effects of dissolved O2, results revealed that increasing the level of dissolved O2 has consequently increased the polarization resistance and shifted the OCP to more positive values. All the generated Nyquist plots exhibited a depressed capacitive loops indicating that corrosion in the designated solution occurred with charge transfer as the rate-determining step.

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