Corrosion Of Aluminum Alloy Research Articles

Research on accelerating the corrosion of 7B04 aluminium alloy in the Lacticaseibacillus paracasei environment

Research on accelerating the corrosion of 7B04 aluminium alloy in the Lacticaseibacillus paracasei environment

Inhibition of the localised corrosion of AA2024 in chloride solution by 2-mercaptobenzimidazole and octylphosphonic acid

The scanning vibrating electrode technique was employed to monitor the in situ localised electrochemical activity on aluminium alloy 2024-T3 at the free corrosion potential in aggressive NaCl solutions with and without corrosion inhibitors 2-mercaptobenzimidazole (MBI) and octylphosphonic acid (OPA). MBI is a very effective inhibitor against pitting corrosion, even in a chloride environment without the reservoir of MBI. In contrast, localised corrosion was observed at several points at the early stage of immersion of AA2024 in NaCl solution containing OPA. Ex situ energy-dispersive X-ray spectroscopy analysis of the Al2CuMg particle at the cross-section revealed that MBI does not entirely prevent its dissolution but reduces the dissolution rate and the rate of oxygen reduction by forming an insoluble complex compound Cu–MBI on the partially dealloyed AlCu-based particles, i.e., on the porous copper remnants. The MBI’s action is an efficient option for mitigating the corrosion of Cu-based aluminium alloys.

Controllable Construction and Corrosion Resistance Mechanism of Durable Superhydrophobic Micro-Nano Structure on Aluminum Alloy Surface

Aluminum alloy corrosion resistance could be improved by micro-nanostructures on superhydrophobic surfaces, but inadequate mechanical stability remains a bottleneck concern in the sector. Herein, femtosecond laser processing and spray modification techniques are employed to fabricate “armor-style” micro-nanostructures on aluminum alloy surfaces. The construction of durable superhydrophobic surfaces was controllably constructed using this strategy. Applying a spray of hydrophobic nano silica onto the surface of aluminum alloys is an effective method for creating a low surface energy coating, while the femtosecond laser-processed “armor-style” micro-nano structure offers additional adhesion sites for the hydrophobic nano-silica. The findings indicated that the treated surface’s contact angle (CA) reached 152.5° while the slide angle (SA) was only 2.3°, exhibiting favorable superhydrophobic performance. Being worn 100 times with 400# sandpaper, the superhydrophobic surface retained a contact angle above 150°. Electrochemical tests demonstrated significant reductions in the self-corrosion current of superhydrophobic surfaces. Meanwhile, the impedance increased significantly, showing good thermal, mechanical, and chemical stability, enabling better sustainable use of aluminum alloys. These results will serve as a theoretical foundation for the surface protection of aluminum alloys.

Corrosion of Aluminum and Aluminum Alloys Used for Rolling Stock

Corrosion of Aluminum and Aluminum Alloys Used for Rolling Stock

A comparative analysis on the effects of sodium nitrate and hexamine on the corrosion of aluminium alloy in an acidic environment

Despite aluminium and its alloys being relatively resistant to corrosion reaction as a result of their passivating tendencies, aluminium alloys usually succumb to acidic attacks resulting in mostly pitting corrosion. This study is focused on comparing the efficiency of sodium nitrate with that of hexamine on the acid corrosion of aluminium when used individually as inhibitors in 1 M Hydrochloric acid. The gravimetric method was used for the corrosion study. Sodium nitrate was found to have higher inhibitor efficiency of 94% compared to that of hexamine (44%), positioning the former as a better inhibitor for aluminium alloy in 1 M HCl. ΔGadso was evaluated and the obtained Standard free energy of adsorption were in the range of −13 to −17 kJ/mol for NaNO3 and −6 to −12 kJ/mol for hexamine, signifying the physisorption mode of adsorption.

Effect of Acinetobacter lwoffi on corrosion behavior of 7B04 aluminum alloy

In this work, the corrosion of 7B04 Aluminum alloy in cultured A. lwoffi was studied using electrochemical and surface analysis techniques. The study found that the presence of bacteria led to an increase in the pH value of the solution when compared to a sterile system. The electrochemical results indicated accelerated anodic dissolution rate and cathodic oxygen reduction rate of Al alloy, resulting in increased corrosion current density in the A. lwoffi system. Surface analysis, such as scanning electron microscope and stereomicroscope, revealed a large number of corrosion pits, and the severity of the corrosion phenomenon was attributed to the denitrification effect of A. lwoffi, indicating that A. lwoffi promoted the corrosion of Al alloy.

On the localized corrosion of AA5083 in a simulated dynamic seawater/air interface—Part 2: effects of wetting time

The effect of wetting time on localized corrosion of AA5083-H111 aluminum alloy in a dynamic seawater/air interface zone was investigated using electrochemical measurements, scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Longer wetting time resulted in a more serious localized corrosion degree and thus led to an uneven and incomplete corrosion product film. This was attributed to the presence of a thin electrolyte layer upon the alloy, restricting the repassivation of the corrosion pits.

Aluminium alloy corrosion inhibition by composite pigment based on nanoporous synthetic zeolite and zinc dihydrogen phosphate

Aluminium alloy corrosion inhibition by composite pigment based on nanoporous synthetic zeolite and zinc dihydrogen phosphate

Inhibition effect of lithium salts on the corrosion of AA1100 aluminium alloy in ordinary Portland cement pastes

The corrosion inhibition effect of LiNO3 and Li2CO3 has been investigated for protecting aluminium alloy 1100 encapsulated in ordinary Portland cement pastes. A combined approach of electrochemical measurements, scanning electron microscopy and gas chromatography revealed that the corrosion rate of AA1100 is effectively inhibited owing to the formation of a protective corrosion product film in cement pastes with the addition of LiNO3 or Li2CO3. Without any inhibitor, the fast corrosion rate leads to visible cracking in the cement paste matrix. Both the hydration evolution and the curing environment of cement pastes play important roles in the corrosion process.

Electrochemical Investigation of the Anti-corrosive Effect of Spondias mombin Leaves Extract on the Corrosion of Aluminium Alloy (AA2024) and Mild Steel in 0.5 M NaCl

The inhibiting effect of Spondias mombin (SM) leaves extract on the corrosion of AA2024 and mild steel in 0.5 M NaCl environment was investigated using electrochemical techniques. Tafel plots obtained from the potentiodynamic polarization (PDP) experiments indicate that for both metals, the curves shifted toward more negative values of the corrosion current density (Icorr) as the inhibitor concentration increased. More so, for all concentrations of the inhibitor, the values of maximum displacement shift in corrosion potential (Ecorr) were found to be less than 85 mV. This shows that SM behaves like a mixed-type corrosion inhibitor. The electrochemical impedance spectroscopy (EIS) study shows that for both metals, the charge transfer resistance (Rct) values increased with an increase in concentration of the inhibitor. The increase in values of Rct can be attributed to the formation of protective film at the metal-solution interface. The Nyquist plots show semi circles whose diameter increased as the inhibitor concentration is increased and this is suggestive of retardation in corrosion process. The inhibition efficiency values obtained in the EIS experiment were found to be in close conformity with those of the PDP experiment.

Effect of Tropical Marine Atmospheric Environment on Corrosion Behaviour of the 7B04-T74 Aluminium Alloy

In this work, the effects of the tropical marine atmospheric environment on the corrosion behaviour of the 7B04-T74 aluminium alloy were systematically investigated by using accelerated testing, together with corrosion kinetic analysis, microstructure observation, product composition analysis, and potentiodynamic polarization curve tests. The weight loss method was used for the corrosion kinetics analysis. The surface morphology and corrosion products transformation law were investigated by OM, SEM, EDS, and XPS. The electrochemical characteristics were studied using potentiodynamic polarization curves. The research indicated that the 7B04-T74 aluminium alloy has eminent corrosion resistance in the tropical marine atmospheric environment. Localized pitting corrosion occurred rapidly in the tropical marine atmosphere. In the later stage of corrosion, the corrosion of aluminium alloy did not become serious. Specifically, no obvious intergranular corrosion was found, which is related to the thermal treatment method. Corrosion products included Al(OH)3, Al2O3, and AlCl3, of which Al(OH)3 is the most notable.

Easy and low-cost transient detection of Al(III) evolution during the galvanic corrosion of aluminum alloys

Corrosion is a serious problem that affects several industries and causes significant economic losses. In recent years, the transportation industry has replaced several ferrous parts with aluminum or magnesium alloys to produce lighter vehicles. Due to this, galvanic corrosion has been more frequent in that industry. In this work, a colorimetric sensor for the detection of Al(III) species during galvanic corrosion is presented. The sensor was made of a chromophore immobilized on a gel electrolyte based on NaCl and agar. The sensor developed a red coloration proportional to the Al(III) concentration under the pH interval studied (3.2–4.5). A galvanic couple consisting of an aluminum alloy and carbon steel was used to test the capacity of the sensor to develop the production of Al(III) into the gel electrolyte and over the whole aluminum surface. Through image processing, it was possible to construct 2D Al(III) concentration maps over time using a commercial aluminum alloy (AA7075) and a castable aluminum alloy from a steering rack as a real sample.Graphical

Corrosion inhibition study of 6061 aluminium alloy in the presence of ethyl 5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazole-4-carboxylate (NTE) in hydrochloric acid

The inhibitory effect of an ethyl 5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazole-4-carboxylate (NTE) was investigated on the corrosion of Al (AA6061) alloy at different temperatures (303–333 K) by Electrochemical impedance spectroscopy (EIS), Potentiodynamic polarization (PDP), and weight loss techniques. It was found that NTE molecules protect the aluminium against corrosion and its ability increases with increasing concentrations, and temperature resulting in better inhibitory performance. At all concentrations and temperature ranges, NTE exhibited mixed inhibitor action and complied with the Langmuir isotherm. At 100 ppm and 333 K, NTE demonstrated the highest inhibition efficiency (94%). The EIS results and the PDP results had a good level of concordance. A suitable mechanism for the corrosion prevention of AA6061 alloy was proposed. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to confirm the adsorption of an inhibitor onto the aluminium alloy surface. The electrochemical results were validated by morphological examination, which demonstrated that NTE prevents uniform corrosion of aluminium alloy in acid chloride solutions. The activation energy and thermodynamic parameters were computed, and the results were discussed.

LDH-Based "Smart" Films for Corrosion Sensing and Protection.

In a "smart" corrosion-protective coating system, both the active anti-corrosion and the early corrosion detection of underlying metals are highly required. It is practical significant to develop materials that possess self-detecting of the early local corrosion and self-healing of coating defects simultaneously. The organic compound 8-hydroxyquinoline (8HQ) is an effective inhibitor and a fluorescent sensor probe for corrosion of aluminum alloy. Therefore, a layer double hydroxide (LDH) nanocontainer film loaded with the 8HQ was developed for the active corrosion protection purpose of aluminum alloy AA2024. In corrosive environments, the 8HQ are released from LDH film to inhibit the corrosion process, leading to the loss of the complexation with Al3+ ions in LDH laminates, thus turning off fluorescence. Results show that the LDH film loaded with 8HQ composites can improve the anti-corrosion performance of the film by releasing corrosion inhibitors on demand. Simultaneously, due to the complexation of 8HQ and Al3+ ions, the LDH film is fluorescent at the initial stage under ultraviolet light, and then becomes non-fluorescent at the corrosion sites, indicating the corrosion evolution process of the coating. The 8HQ-loaded LDH film with self-healing and self-detecting dual functions provides promising opportunities for the effective corrosion protection of aluminum alloy due to its "smart" and multifunctional properties.

Corrosion behaviour of Tribaloy T400 coating prepared by laser cladding in molten aluminium alloys

Corrosion of molten Aluminium alloys is an important reason to lead the failure of moulds. The Tribaloy T400 coating was prepared on H13 steel by laser cladding to investigate corrosion behaviour in molten A356 Aluminium alloys at 993 K for different periods. The main phases in the Tribaloy T400 coating were primary Co-rich FCC phase and Laves phase (Co7Mo6 and Co3Mo2Si). The Tribaloy T400 coating maintain its surface integrity after immersion in molten Aluminium alloy for 7d. The corrosion resistance was improved significantly compared to H13 steel substrate. The Vickers hardness of the coating was increased from 686 to 727 HV0.3, which could be attributed to the obvious aging hardening effect in Tribaloy T400 coating.

Effects of tannic acid on film formation process of colored Ti/Zr-based conversion coatings

Corrosion of aluminum (Al) alloys represents a major issue in industrial applications, giving rise to safety concerns and enormous economic loss. Chromate conversion coatings (CCCs) have been widely used in industry over the past decades, providing exceptional corrosion protection for aluminum alloys at a relatively low cost. However, new environmental regulations prohibiting the use of chromium (VI) (Cr6+) have raised a growing interest in the development of alternative technologies to CCCs, but only titanium (Ti)/zirconium (Zr) conversion coatings have been used in industrial applications thus far. However, there remain some disadvantages to these coatings, such as colorless appearance and poor corrosion resistance, which affect their wide application. Here, a colored titanium/zirconium-based conversion coating, formed on aluminum alloy 6063 using a solution containing tannic acid (TA; C76H52O46), hexafluorozirconic acid (H2ZrF6), hexafluorotitanic acid (H2TiF6) and sodium metavanadate (NaVO3), was developed recently by the authors, enabling rapid film formation at room temperature and improved corrosion resistance. The influence of TA on the film-forming process of colored titanium/zirconium-based conversion coatings was investigated using the ultraviolet–visible spectrophotometry, X-ray photoelectron spectroscopy and infrared spectroscopy techniques, and the possible reaction process after adding TA, as well as the mechanism of rapid film formation and color rendering, was also explored. The results showed that the large number of organic complexes formed by TA with metal ions during the aging process of conversion solution and film formation was the main reason for the rapid film formation and color rendering of the coating.

Insight into Intergranular Corrosion of the Aluminum Alloy 2024-T3: Effect of Pre-Charged Hydrogen

2024-T3 aluminum alloy has been widely applied in aviation fields, whilst the accumulation of hydrogen at grain boundaries deteriorates the mechanical properties and corrosion resistance. The intergranular corrosion of 2024-T3 related to hydrogen permeation was investigated. Atom probe tomography was used to observe the precise position of hydrogen atoms in relation to grain boundaries. The ionic current density of the H pre-charged surface was studied by in situ scanning vibrating electrode technique. Results show that the distribution of H is highly related to the S-phase at grain boundaries and the H pre-charging significantly improves the charge transfer efficiency at the initial period of intergranular corrosion process while the enhancement effect is then gradually weakened. The study provided new insight into hydrogen distribution at grain boundaries and its impact on the intergranular corrosion of 2024-T3 aluminum alloy, which can be informative and instructive for the research of corrosion in aluminum alloy.

In Situ Electrochemical Monitoring of the Crevice Corrosion Process of the 7075-T651 Aluminium Alloy in Acidic NaCl and NaNO3 Solution

The crevice corrosion of the 7075-T651 aluminium alloy was investigated using in situ electrochemical impedance spectroscopy (EIS), potentiodynamic polarization curves (PC), and H+ sensors in acidic NaCl solution with different contents of NaNO3. In the solution without NaNO3, the pH in the crevice increased rapidly and gradually reached a relatively stable status. The corrosion of the aluminium alloy in the crevice was inhibited and crevice corrosion could not be initiated. In the solution with NaNO3, the pH increased rapidly at the initial immersion period and then decreased gradually. The corrosion of the aluminium alloy inside the crevice could be enhanced and the corrosion of the aluminium alloy outside crevice could be inhibited. This triggered crevice corrosion in the solution with NaNO3. The inhibited corrosion outside the crevice can be attributed to the improved passive film of the specimen outside the crevice by nitrate. The accumulated secondary products of ammonia inside the crevice led to selective dissolution of copper, which triggered the nucleation of pitting corrosion and promoted the corrosion of the specimen inside the crevice.

Green Inhibition of Corrosion of Aluminium Alloy 5083 by Artemisia annua L. Extract in Artificial Seawater

Plant extracts are increasingly being examined in the corrosion inhibition of metal and alloys in various environments due to their potent antioxidant properties. The use of Artemisia annua L. aqueous extract (AAE) as an aluminium alloy 5083 (ALA) corrosion inhibitor in artificial seawater (ASW) was investigated using electrochemical tests and spectroscopy tools, while the active biocompounds found in AAE were analyzed using high-performance liquid chromatography (HPLC). Electrochemical results showed that AAE acts as an anodic inhibitor through the physisorption (ΔG ≈ -16.33 kJ mol-1) of extract molecules on the ALA surface, thus reducing the active sites for the dissolution of the alloy in ASW. Fourier-transform infrared spectra confirmed that phenolic acids found in AAE formed the surface layer that protects ALA against the corrosive marine environment, while HPLC analysis confirmed that the main phytoconstituents of AAE were chlorogenic acid and caffeic acid. The inhibition action of phenolic acids and their derivatives found in the AAE was based on the physisorption of caffeic acid on the ALA surface, which improved physicochemical properties of the barrier film and/or conversion of Al3+ to elemental aluminium by phenolic acids as reducens, which slowed down the diffusion rate of Al3+ to or from the ALA surfaces. The protective effect of the surface layer formed in the presence of AAE against ASW was also confirmed by inductively coupled plasma-optical emission spectrometry (ICP-OES) whereby the measured concentration of Al ions after 1 h of immersion of ALA in the pure ASW was 15.30 μg L-1 cm-2, while after the addition of 1 g L-1 AAE, the concentration was 3.09 μg L-1 cm-2.

Effect of Cathode Distance, Anode and Electroplating Time on Aluminum Alloy Corrosion Rate

Aluminum foil is used more often than actual aluminum in everyday life because aluminum is actually quite unstable and is not suitable for securing heavy containing objects. For car wheels, aluminum is mixed with manganese and then hardened to withstand the load. Using aluminum alloys requires an electroplating process to increase corrosion resistance, decorative value and friction resistance. The purpose of this study was to determine the properties of anodized cathode aluminum alloy and the required coating time. In this study, a quantitative experiment used 20 samples. The results showed that there were defects in the aluminum alloy lattice, but not too significant. Different corrosion rate values were shown using electrolysis periods of 30 minutes and 60 minutes combined with anode-cathode distances of 5 cm, 10 cm and 15 cm. The group with 30 minutes of coating time and 5 cm anode-cathode distance had the highest corrosion rate (0.853 mm/year), while the group with 30 minutes of coating time and 10 cm anode-cathode distance had the lowest corrosion rate (0.610). The group with 60 minutes of coating time and 10 cm distance between the anode and cathode had the highest corrosion rate of 1,564 mm/year, while the group with 60 minutes of coating time and 15 cm distance had the lowest corrosion rate. The anode-cathode distance partially affects the corrosion rate of aluminum alloy electroplating. The smaller the distance between the anode and cathode, the higher the corrosion rate of the aluminum alloy. The longer the coating lasts, the higher the corrosive rate of the Al alloy.