Corrosion Of Aluminum Alloy Research Articles

Corrosion resistance and antibacterial activity of 2-mercaptobenzothiazole for 7B04 aluminium alloy in 3.5%NaCl solution

In this paper, the inhibition effect of 2-mercaptobenzothiazole (MBT) on microorganisms in the fuel system and corrosion inhibition of 7B04 aluminum alloy are studied, and the mechanism is discussed. The antibacterial activity of MBT is studied by microbial experiments. The agar diffusion test demonstrates the significant antibacterial efficacy of MBT against Lysinibacillus sphaericus (L. sphaericus) and Acinetobacter lwoffii (A. lwoffii) strains isolated from aircraft fuel systems, and the bacteriostatic effect on L. sphaericus is better. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PDP) results show that MBT inhibits the corrosion of 7B04 aluminum alloy by forming a protective film on the aluminum alloy surface and inhibiting the cathode reaction. In this study, the most effective corrosion inhibition concentration of MBT is 200 mg∙L−1, with a maximum corrosion inhibition rate of 99.27%. Langmuir adsorption isotherm results further indicate that MBT acts on the aluminum alloy surface by physical adsorption and chemical adsorption. The scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) results confirm that MBT form a protective adsorption film on the aluminum alloy surface, which effectively shield the corrosive media on the surface. Furthermore, density functional theory (DFT), Monte Carlo simulation (MC), and molecular dynamics simulation (MD) are employed to identify the active sites of MBT as N and S atoms and to demonstrate that MBT adsorb onto the aluminum alloy surface in a horizontal orientation.

Caesalpinia crista seed is used as an eco-friendly inhibitor to prevent the corrosion of aluminium in hydrochloric acid solutions

This investigation delves into the inhibitory impact of Caesalpinia crista (Kanchaki) seed extract (CCE) on the corrosion of aluminium alloy (AA6061) at temperatures varying between 303 and 333K, employing Potentiodynamic Polarisation (PDP), Electrochemical Impedance Spectroscopy (EIS), and weight loss methodologies. Findings demonstrate that CCE extract effectively safeguards Al against corrosion, with efficacy increasing at higher concentrations. The observed inhibitory action exhibits a cathodic-type behavior across all concentrations and temperatures, aligning well with Langmuir isotherm. Notably, the highest level of inhibitory efficiency, reaching 96.87 ​%, is attained at a concentration of 2.0 ​g/L and a temperature of 303 ​K for 3 hours. Consistency is observed between the results obtained through EIS and PDP. A plausible mechanism for preventing corrosion in Al alloy is proposed. Surface analysis techniques, such as Atomic Force Microscopy (AFM) and Scanning Electron Microscopy/Energy Dispersive X-ray analysis (SEM/EDX), validate the adsorption of the inhibitor onto Al alloy surfaces. Morphological examinations corroborate electrochemical findings, confirming protection against uniform corrosion in HCl solutions. Additional analyses involve the computation of activation energy and thermodynamic parameters, with a thorough discussion of the results.

Atmospheric corrosion and mechanical property degradation of 2524-T3 aluminum alloy in marine environments

Atmospheric corrosion and the resulting mechanical property degradation of 2524-T3 aluminum alloy in marine environments with different environmental factors are investigated. 2524-T3 aluminum alloy exhibits the most severe corrosion in tropical marine atmosphere, attributed to the highest temperature, humidity, rainfall, Cl- deposition rate, and the longest time of wetness. The EIS results are closely related to the corrosion evolution process. The degradation sensitivity indexed by elongation, reduction-in-area, and tensile strength is correlated with the average corrosion-induced surface defect depth (D′ave), while the elasticity modulus is related to the maximum corrosion penetration depth (Dmax).

Anticorrosion mechanism of epoxy coating containing mesoporous resorcinol-formaldehyde hollow nanosphere loaded with 8-Hydroxyquinolin

Mesoporous resorcinol-formaldehyde hollow nanosphere (MRFHN) with erythrocyte like shape was prepared successfully. The average diameter, shell thickness, and specific area of MRFHN are 223 nm, 42 nm, and 73.2 m2/g, respectively. The average loading capacity of 8-Hydroxyquinoline (8-HQ) in MRFHN is 33 % and the sucked 8-HQ can release continuously from MRFHN. MRFHN loaded with 8-HQ (MRFHN@8-HQ) was introduced into epoxy coating to enhance its anticorrosion performance. The results show that epoxy coating pigmented with MRFHN@8-HQ has a higher anticorrosion performance than neat epoxy coating. Especially, epoxy coating containing 4 wt% of MRFHN@8-HQ presents the best anticorrosion performance and self-healing function, and its coating resistance is still maintained at 109 Ω cm2 even after 50-day immersion in 3.5 wt% NaCl solution. Meanwhile, the scratch on coating surface is covered by a thin layer of 8-HQ which can prevent the AA2024 aluminum alloy from corrosion even after 50-day neutral salt spray test. 8-HQ can release from MRFHN and form a compact inhibiting layer on AA2024 aluminum alloy surface, thus the corrosion of AA2024 aluminum alloy is suppressed effectively. MRFHN@8-HQ can be used as a high performance anticorrosion pigment to give epoxy coating a long term protection.

Effect of Fatigue and Precorrosion Fatigue on Fatigue Crack Propagation and Fracture Failure Behavior of 5B70 Aluminum Alloy

Aluminum alloys are ideal lightweight structural materials for spacecraft, but they are susceptible to local corrosion during service. Herein, a systematic investigation is carried out to determine the fatigue behavior of 5B70 aluminum alloy under salt spray precorrosion. The mechanism of salt spray corrosion, fatigue life, crack propagation, and failure fracture mechanism of 5B70 aluminum alloy are studied. Under the salt spray corrosion, 5B70 aluminum alloy mainly undergoes pitting corrosion via a galvanic corrosion mechanism. After precorrosion, the formation of macroscopic fatigue cracks is accelerated, which significantly reduces its fatigue life. Fracture occurs due to single crack initiation and propagation under fatigue conditions. The fatigue crack tip undergoes a mixture of intergranular and transgranular modes, but mainly transgranular mode. Multiple strain localization phenomena occur during precorrosion fatigue, and corrosion pits on the surface provide a tortuous crack propagation path; the fatigue crack tip is mainly transgranular mode.

Comprehensive evaluation of fungal-induced corrosion in aluminum alloys by Amorphotheca resinae

Amorphotheca resinae is a fungus that particularly corrodes aeronautical aluminum alloys, leading to economic issues in various industries. This study aims to investigate the effects of this fungus on the corrosion of four different aluminum alloys, namely 2024, 7075, 5083, and 3105, after 25, 50, and 75 days through scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), 3D profilometry, weight loss (%) measurement, energy dispersive spectrometry (EDS), electrochemical impedance (EIS), and pH changes. After 25 days, the 2024 alloy had the highest mycocorrosion rate (1.3417 mpy), while alloy 3105 had an undetectable value on this day. According to the EIS test, the 3105 alloy had the highest level of resistance (1.12 × 105 Ω cm2) to corrosion, while the 2024 alloy was the most susceptible (7138 Ω cm2). The qualitative data from SEM, CLSM, and 3D profilometry also confirmed the quantitative findings where the surface pits on the 2024 alloy were deeper than those of other alloys. Overall, the results showed that the lowest and highest corrosion rates mediated by A. resinae belonged to 3105 and 2024 alloys, respectively. These findings could have significant implications for industries that use aluminum alloys and might help in developing strategies to prevent or control biocorrosion.

Effect of two-step anodizing on corrosion and adhesion resistance of A5052 aluminum alloy

Effect of two-step anodizing on corrosion and adhesion resistance of A5052 aluminum alloy

How Often Should Microbial Contamination Be Detected in Aircraft Fuel Systems? An Experimental Test of Aluminum Alloy Corrosion Induced by Sulfate-Reducing Bacteria.

Microbial contamination in aircraft fuel-containing systems poses significant threats to flight safety and operational integrity as a result of microbiologically influenced corrosion (MIC). Regular monitoring for microbial contamination in these fuel systems is essential for mitigating MIC risks. However, the frequency of monitoring remains a challenge due to the complex environmental conditions encountered in fuel systems. To investigate the impact of environmental variables such as water content, oxygen levels, and temperature on the MIC of aluminum alloy in aircraft fuel systems, orthogonal experiments with various combinations of these variables were conducted in the presence of sulfate-reducing bacteria. Among these variables, water content in the fuel oil demonstrated the most substantial influence on the corrosion rate of aluminum alloys, surpassing the effects of oxygen and temperature. Notably, the corrosion rate of aluminum alloys was the highest in an environment characterized by a 1:1 water/oil ratio, 0% oxygen, and a temperature of 35 °C. Within this challenging environment, conducive to accelerated corrosion, changes in the corrosion behavior of aluminum alloys over time were analyzed to identify the time point at which MIC intensified. Observations revealed a marked increase in the depth and width of corrosion pits, as well as in the corrosion weight-loss rate, starting from the 7th day. These findings offer valuable insights for determining the optimal frequency of microbial contamination detection in aircraft fuel systems.

A dual UV light-trigged and pH-responsive release system based on functional ZIF-8

We developed zeolitic imidazolium framework-8 (ZIF-8) complexes loaded with cerium corrosion inhibitor and pH-jump reagent 2-nitrobenzaldehyde (ONBA), called ZIF-8/Ce@ONBA, for the intelligent control of metal corrosion by using a simple one-pot method. The pH-jump reagent can utilize ultraviolet (UV) light to induce the acidic degradation of ZIF-8 and achieve the controlled release of cerium inhibitor. The measurement results of the inductively coupled plasma mass spectrometry show that the release of cerium ions from the ZIF-8/Ce@ONBA reaches 42 mg/L after 9 h of UV irradiation. The release amount can reach 53 mg/L under a pH of 3 for 24 h. The results of electrochemical measurements and corrosion morphology observations also confirm that the fabricated ZIF-8/Ce@ONBA considerably suppresses the corrosion of aluminum alloy. Furthermore, these pH-responsive and UV-triggered properties endow the composite coating with a short-time self-healing ability and an excellent anticorrosion performance. These results underscore the potential of this composite to provide an efficient and intelligent delivery of corrosion inhibitors to metals for corrosion protection. This composite also presents an avenue for developing sustainable industrial corrosion protection.

The influence Cl− on stress corrosion of 7xxx series aluminium alloys studied by experimental and simulation technology

The stress corrosion behavior of 7xxx series aluminium alloys in different concentrations NaCl solution was studied, and numerical simulation was conducted in COMSOL Multiphysics based on experimental results. Different stresses were applied on the experiment pieces, the pitting crater deepened with the change of stress level. The corrosion rate increased with the raising stress. There is no positive correlation between stress corrosion degree and chloride ion concentration. The most severe corrosion occurs in 5.0 wt% NaCl solution instead of 6.0 wt% NaCl solution due to the increase of water film conductivity and decrease of solubility of oxygen under high Cl− environment. The finite element model was used to analyze the stress distribution on aluminium alloy surface, to describe the dynamic equation of anodic dissolution of metal due to elastic and plastic deformation. Corrosion occurs mainly in stress concentrated areas. When the stress loading exceeds a certain threshold, plastic strain occurs on the surface of both the specimen and the structural part, the corrosion current density increases instantaneously, and the corrosion behavior in the stress concentration area gradually intensifies. The survey can provide practical theoretical guidance for predicting stress corrosion and extending the service life of equipment in (harsh) marine environments.

Study of process parameters and deposition mechanism of composite co-deposited Cu/Co-Mo-Ce on aluminum alloy surface

The 6061‑aluminum alloy is most used in marine engineering equipment. We used composite co-deposition to prepare a Cu/Co-Mo-Ce alloy coating on the aluminum alloy surface, which not only solved problems related to the ready corrosion of aluminum alloy in marine environments and the difficulty of directly preparing protective coatings but also solved problems associated with the fact that CoMo alloy form many holes by introducing the rare earth Ce. An exploration of the plating process revealed that when the concentration of the other main salts was unchanged and the concentration of Ce3+ was 0.012 mol·L−1, the Cu/Co-Mo-Ce had the flattest morphology, and the best corrosion resistance. The coatings were characterized and analyzed using SEM, EDS, XRD, and XPS. Finally, the ions deposition processes were tested via cyclic voltammetry and chronoamperometry and AC impedance.

Experimental and theoretical studies on the electrochemical behavior of Al alloy treated by cyclohexanol-based inhibitor

Corrosion of aluminum alloys in aggressive environments such as seawater and industrial processes is a major challenge due to its negative impact on the mechanical properties, safety, and economic performance of the alloy. In this context, employing corrosion inhibitors stands out as one of the greatest effective approaches for combating the effects of this phenomenon. However, most commonly used inhibitor molecules are non-biodegradable and can cause adverse health and environmental effects. In this work, the corrosion inhibitive effect of Ethyl 3 – benzoyl -1- cyano-4 - hydroxy-2,4,6-triphenylcuclohexane-1-carboxylate (EBCHTC) was examined. This performance was investigated using some experimental tests such as gravimetric analysis, electrochemical measurements, and surface characterization. The findings indicate that the EBCHTC substantially improves corrosion resistance, achieving an efficiency of 93% with an optimal concentration of 1×10-3 M at 25°C. To understand the adsorption ability and stability of the inhibitor on the 3003 AA surface, various concentrations and temperatures with and without inhibitor was tested. The results show an out-standing inhibition efficiency in the diverse experimental environments, the EBCHTC belong to mixed-type inhibitor and the adsorption of the inhibitor molecules on the 3003AA surface is spontaneous and is physical-chemical adsorption. The capacity of the EBCHTC to act as a good anti-corrosion agent was justified using the computational tools. The drawn-in-silico conclusions are in good arrangement with experimental results.

Experimental and theoretical investigations of the anti-corrosion film derivated from bio-based melatonin on AA5052 aluminum alloy surface

In this work, the effect of the bio-based melatonin (MEL) on the corrosion inhibition of AA5052 aluminum alloy in 3 wt% NaCl solution has been studied by weight-loss experiments, electrochemical measurements and surface analysis. MEL inhibits the corrosion of AA5052 aluminum alloy in 3 wt% NaCl solution very well, resulting in a positive shift of the corrosion potential and the pitting potential. The corrosion inhibition efficiency reaches 71.76% at 2 mM MEL. The FT-IR, SEM, XPS and theoretical calculation are used to investigate its corrosion inhibition mechanism. It indicates that MEL coordinates with Al3+ ions via its N (9) atom and O (10) atom to form a surface complex film. This protective film retards the corrosion of AA5052 aluminum alloy significantly. This biomolecule is a promising anti-corrosion additive to protect aluminum alloys heat-exchange in seawater desalination plant.

High temperature corrosion behavior of ADC12 aluminum alloy in oxalic acid solution

High temperature corrosion of ADC12 aluminum alloy in oxalic acid solution was investigated using weight loss, electrochemical measurements, surface technologies. The results showed that at room temperature, the aluminum alloy exhibited localized corrosion, while at high temperatures, it exhibited uniform corrosion. As the temperature rose from 30 °C to 90 °C, the rapid dissolution of its passivation film led to a 70.19% increase in the corrosion rate. After soaking for 72 h, its corrosion rate decreased by 74.35% because of the depletion of hydrogen ions and the accumulation of corrosion products. The corrosion products were mainly Al2O3 and aluminum oxalate.

Study on oxidation mechanism of aluminum surface under applied electric field

The oxidation behavior of aluminum alloy has a significant impact on its industrial application of aluminum alloy, and studying how aluminum alloy oxidizes in electrolyte solutions is crucial. However, current research predominantly focuses on aluminum anodization at higher voltages and the second-phase corrosion behaviors in halide ion-containing solutions. The research on the formation mechanism of the oxide film on the aluminum surface lacks in-depth analysis, and there is no unified opinion on the method of oxygen invasion into the oxide film. This study establishes an experiment on the corrosion of aluminum alloy in an oxygen-free water environment. By scrutinizing the oxidation behaviors of aluminum surface under conditions of no voltage and low voltage, we investigate the effect of applied electric field on the mode of oxygen invasion in alumina. The findings reveal that under the condition of no external voltage and an alkaline environment, self-passivation products of aluminum undergo a transformation from AlO(OH) to Al(OH)3 as the pH value increases. At a pH of 10, complete transformation into Al(OH)3 occurs. When external voltage is applied, Al(OH)3 is initially formed on the aluminum surface with an increase of potential. As the potential reaches a certain value, the potential energy barrier for the reaction of H and O in OH− is disrupted, leading to the reaction of Al3+ replacing H+ and generating an Al2O3 film, with the current on the membrane surface changes unevenly during this process, resulting in the emergence of a double-layer film structure on the aluminum surface. Therefore, under the electrochemical environment of applying a small current, the film formation process on the surface of aluminum alloy is carried out under the action of OH− heterocracking in water, and the O in the water molecule forms two distinct oxide films with the Al matrix in the form of O2− and OH−.

Effect of L-Cysteine on Micro-Galvanic Corrosion of ADC12 Aluminum Alloy in a Low-Conductivity Coolant for Electric Vehicles

L-cysteine as a corrosion inhibitor for ADC12 aluminum alloy in a modified coolant solution was investigated. Results reveal its effectiveness as a cathodic inhibitor, suppressing the oxygen reduction reaction. Immersion tests show efficient inhibition of localized corrosion at an optimized L-cysteine concentration of 1.0 mM. A favorable L-cysteine adsorption on θ-Al2Cu is confirmed, enhancing hydrophobicity, and leading to corrosion inhibition. This study proposes a tentative corrosion inhibition mechanism.

Electrochemical behaviour of thermally treated aluminium 2024 alloy exposed to B. mojavensis

The copper-rich zone plays a key role in understanding the deterioration process of 2024 aluminium alloy. The intermetallic on the surfaces makes this alloy susceptible to both local corrosion and microbial colonization. The adhesion of bacteria on the surface could deteriorate the metallic substrate in a phenomenon known as microbiologically influenced corrosion (MIC). The triggering mechanism of MIC in 2024-T3 is unclear. An electro­chemical study was conducted to determine the influence of the second phase (Al2Cu) on the corrosion of the 2024-T3 aluminium alloy exposed to bacteria. The 2024-T3 alloy was thermally treated to increase the amount of Al2Cu by nearly 67 % on the surface. The bacterium under study was collected from the corrosion products of a Chilean Air Force aircraft. The isolated bacterium was identified by 16S RNA sequencing as Bacillus mojavensis (99.99 %). Results obtained by electrochemical impedance spectroscopy showed a decreased impedance of 2024-T3 and an increased impedance of heat-treated, both samples exposed to bacteria. The increased impedance could be associated with the antibacterial effect due to the high ion release of copper on the surface, which can inhibit biofilm formation and biocorrosion.

The investigation of Bacillus cereus induced degradation of passive films of 5A06 aluminium alloy in simulated condensate solutions of space station

Microbiologically influenced corrosion in water recovery system of manned spacecrafts deserves attention. The effect of Bacillus cereus on the corrosion of 5A06 aluminium alloy in simulated condensate solutions of space station was investigated. The organic acids induced significant dissolution of aluminium alloy, electrochemical measurements results showed living cells could weakened the cathode reaction, and focused ion beam-scanning/transmission electron microscopy indicated that B. cereus cell promoted the thinning of passive films. B. cereus affected the corrosion of 5A06 AA through metabolic activities and extracellular polymeric substances, ultimately promoting the degradation of passive films of aluminium alloy.

MgO/KH2PO4 and Curing Moisture Content in MKPC Matrices to Optimize the Immobilization of Pure Al and Al-Mg Alloys.

Magnesium Potassium Phosphate Cements (MKPCs) are considered a good alternative for the immobilization of aluminium radioactive waste. MKPC composition and moisture curing conditions are relevant issues to be evaluated. The corrosion of pure aluminium (A1050) and AlMg alloys (AA5754) with 3.5% of Mg is studied in MKPC systems prepared with different MgO/KH2PO4 (M/P) molar ratios (1, 2, and 3M) and moisture curing conditions (100% Relative Humidity (RH) and isolated in plastic containers (endogenous curing)). The Al corrosion potential (Ecorr) and corrosion kinetic (icorr and Vcorr) are evaluated over 90 days. Additionally, the pore ion evolution, the matrix electrical resistance, the pore structure, and compressive strength are analysed. The corrosion process of Al alloy is affected by the pH and ion content in the pore solution. The pore pH increases from near neutral for the 1M M/P ratio to 9 and 10 for the 2 and 3M M/P ratio, increasing in the same way the corrosion of pure Al (AA1050) and AlMg alloys (AA5754). The effect of Mg content in the alloy (AA5754) becomes more relevant with the increase in the M/P ratio. The presence of phosphate ions in the pore solution inhibits the corrosion process in both Al alloys. The MKPC physicochemical stability improved with the increase in the M/P ratio, higher mechanical strength, and more refined pore structure.

New morpholino acetamide ligand's rare earth metal complexes through synthesis, structural, and theoretical studies. Effect of ligand on aluminum alloy corrosion inhibition

A series of new complexes of the general formula [Ln(L)Cl2]Cly·4H2O (Ln = Er and Ta) and [Yb(L)(H2O)2]Cl3, L = N,N'-((ethane-1,2-diylbis(sulfanediyl))bis(2,1-phenylene))bis-(2-morpholino-acetamide) were synthesized and characterized. The physical properties of these complexes were investigated including melting point, color, and percentage yield. Spectral and physico-analytical techniques collectively with elemental analyses were utilized to structurally elucidate the synthesized complexes. At room temperature, complexes exhibited similar solution absorption spectra in the UV–Vis region. As shown by thermal analysis, the complexes lose water molecules first, then anions, and finally ligand molecule, leaving a metal oxide residue. The complexes resulted from monomolar coordination of neutral tetradentate ligand through the two amide nitrogen and the two sulfur, with octahedral geometries. Ligand and its Ta(V) complex were structurally characterized by X-ray powder diffraction. Their optical band gaps demonstrated the ligand and complexes have semiconducting properties. Multiple bonding patterns were discovered in molecular docking simulations of the ligand against SARS-CoV-2 (6Y84) and E. coli DNA gyrase (5MMN). The binding energy of the complexes revealed active compounds capable of inhibiting SARS-CoV-2 and E. coli DNA gyrase. The antioxidant activity of the ligand and its Ln-complexes was investigated, yielding some surprising results. Finally, it is worthy to note that, the biochemical outcomes revealed that these complexes may be promising antibacterial agents. Aluminum alloys (AlSi) corrosion inhibition was investigated in 1 M HCl using potentiodynamic polarization (PP) and electrochemical impedance spectroscopy (EIS). The inhibition efficiency was found to be 96.36 % at 500 ppm inhibitor in 1 M HCl.