Corrosion Rate Of Aluminum Alloy Research Articles

Microbial corrosion behavior and mechanism of 5A06 aluminum alloy under low dose proton radiation

Low-dose proton radiation is one of the important factors that have a major impact on microorganisms in spacecraft. In this paper, the changes in the life activity characteristics of Penicillium oxalate and its impact on the corrosion behavior and mechanism of 5A06 aluminum alloy under low-dose proton radiation have been reported. The results show that the survival rate of the fungus is only 24.8 % under the low radiation condition, but its growth rate is faster and the content of organic acid produced by the metabolism of the fungus is higher per unit. The fungal attachment area was deeper and corroded more severely. Electrochemical tests have shown that the corrosion rate of aluminum alloy is related to the organic acid content in the metabolic solution, so the accumulation of organic acids is considered the main reason for the sever and faster corrosion of 5A06 aluminum alloy under low radiation.

Effect of anodizing on aluminum alloy 2024 with boric sulfate acid in medium 3.5 % NaCl

The utilization of metal materials finds widespread applications in various industries, including the aircraft industry, where aluminum alloys are commonly employed. However, metal materials are prone to corrosion under specific conditions, necessitating the implementation of corrosion prevention methods to decelerate the material's corrosion rate. Corrosion is a process in which the quality of metal deteriorates due to environmental influences. An effective approach to inhibit corrosion is through anodizing, which involves applying a protective coating to the metal surface, preventing direct contact with the surrounding environment. In this research, the focus was on studying the corrosion rate of aluminum alloy 2024 using Boric Sulfate Acid Anodizing (BSAA) at 10 volts and immersion times of 10, 15, and 20 minutes, followed by sealing with acetic acid in a corrosive environment containing 3.5 % NaCl. The main goals were to evaluate the effectiveness of anodizing with and without sealing in lowering the rate of aluminum corrosion, to compare the effectiveness of anodizing with and without sealing, and to create adsorption models using Langmuir adsorption. Through the examination of the potentiodynamic approach, it was shown that anodizing had an inhibitory impact that was strengthened by sealing. The maximum efficiency of 76 % was attained after 20 minutes of anodizing and sealing at 10 volts. A correlation value of 0.7487 from the Langmuir adsorption modeling was also obtained, pointing to an advantageous adsorption behavior. This research demonstrates how effectively anodizing for aluminum alloy 2024 works with and without sealing, especially in a 3.5 % NaCl-corrosive environment

Investigation on AC corrosion of aluminum alloy sacrificial anode in the artificial simulated seawater environment

The alternating current (AC) density induced by submarine cables, which are parallel to submarine pipelines, has nonnegligible effects on the sacrificial anode system of submarine pipeline. The objective of this work is to clarify the AC corrosion of aluminum alloy sacrificial anode. The weight loss tests show that the corrosion rate of aluminum alloy increases with the increase in AC density, whereas the corrosion pits are obvious and dense. The calculated AC current efficiency for aluminum alloy is obviously higher than that for carbon steel under the same condition. The analyses of polarization characteristics and local environment reveal that the activity of aluminum alloy increases under the combined action of alloying elements and AC interference. Furthermore, the surface characteristics verify that Al and the alloying elements (Zn or In) in the solid solution with aluminum are oxidized during the anodic half cycles of AC density. And the alkaline environment created by the cathodic reaction in the cathodic half cycles is beneficial to the dissolution of aluminum alloy. In the condition of high AC density, the vigorous gas evolution is observed on coupon surface, resulting in the formation of larger corrosion pits due to the intrinsic effects of the adsorbed hydrogen and hydrogen bubbles. These results provide a guidance to understand the mechanism of AC corrosion for aluminum alloy exposed to artificial simulated seawater environment.

Influence of Electron Mediator on Microbiologically Influenced Corrosion Behavior of 2024 Aluminum Alloy

In microbiologically influenced corrosion (MIC) caused by sulfate-reducing bacteria (SRB), extracellular electron transfer (EET) between metals and microorganisms affects the metal corrosion process. In this work, the effect of the electron mediator riboflavin on the EET-MIC behavior of 2024 aluminum alloy (AA2024) was investigated by electrochemical methods, surface analysis techniques, focused ion beam, scanning electron microscopy, and x-ray photoelectron spectroscopy techniques. The results showed that the electron mediator was significantly able to accelerate SRB attack against AA2024. SRB utilized to consume H+ to accelerate its own metabolism and promoted the corrosion of AA2024, resulting in the formation of corrosion product AlOOH and Al(OH)3. The addition of electron mediator riboflavin increased the electron transfer efficiency and affected the reaction rate constant to accelerate the corrosion rate of aluminum alloy. The addition of 10 ppm riboflavin led to denser corrosion product biofilms on the surface of the aluminum alloy, which accelerated the formation of NaAlO2. Cl− diffused into the film layer through the pores of the surface of the aluminum alloy and was adsorbed into the film layer to induce pitting corrosion on the surface of the aluminum alloy. A large amount of SRB was attached, which resulted in an increasing pit depth on the surface of the aluminum alloy. Riboflavin accelerated the electron transfer process from the surface of the aluminum alloy across the cell wall to the cytoplasm, which led to serious corrosion of the aluminum alloy. The distribution of SRB in biofilm and the longitudinal distribution of bacteria in the process of pitting corrosion showed that the addition of electron mediators increased the depth of pits in aluminum alloys. Bacteria in the pitting area gathered at the bottom of the biofilm, and the pits were rich in Ca, P, and other elements.

Analysis and calculation of corrosion rate of aluminum alloy in nitric acid solution

In this paper, the polarization curve and corrosion amount of aluminum alloy 1050 in 30 mass% nitric acid solution were measured as the corrosion potential under natural corrosion. it was found that the surface corrosion of aluminum alloy was uniformed and the corrosion rate calculated according to the weight loss-time curve was 0.25 mA·cm−2 by observing the corrosion morphology. The polarization resistance curve was obtained by differentiating the polarization curve. The corrosion rate calculated by analyzing the characteristics of the polarization resistance curve was 0.29 mA·cm−2, which was close to the actual corrosion rate obtained by chemical erosion.

Investigation of Metal Cation Effects on Corrosion Behavior of Aluminum Alloys

Introduction Due to excellent mechanical property and corrosion resistance, aluminum alloys are widely used in airplanes, automobiles, and kitchen utensils. The corrosion resistance of aluminum alloys relies on highly protective and reformative passive films. However, the passive films are destroyed in presence of chloride ions, and the corrosion rate of aluminum alloys depends on the concentration of chloride ions 1 - 3. A few studies have shown the corrosion behavior of aluminum alloys in freshwater; however, the corrosion rates of aluminum alloys were changed in freshwater which sampled different place 4. Because freshwater also contains some metal cations in dilute concentration. The authors expected that the metal cations changed the corrosion rate of aluminum alloy in freshwater. The authors have been investigated the corrosion of A3003 aluminum alloy in freshwater focused on the effects of metal cations5 - 8. The corrosion rate of A3003 aluminum alloy is changed with metal cations in model freshwater despites the concentration of chloride ions, dissolved oxygen and pH are the same. The researches also clarified that Zn2+ is the best metal cation to inhibit the freshwater corrosion of A3003 among the metal cations used6, 7. An Auger spectroscope was used to investigate the corrosion morphology and composition of corrosion products of A3003 formed in model freshwater with different Zn2+ concentration8. From the cross-sectional AES point analysis, it has been clarified that the corrosion products have multi-layer structure.However, it is not fully elucidated the role of the metal cations on the corrosion behavior of aluminum alloys. The purpose of this study is to investigate the effects of metal cations on corrosion behavior of aluminum alloys in aqueous environment. Experimental Sheets of aluminum alloys (A7075, A6061and A2024) were used as the specimens. The sheets were cut into 7 7 mm for immersion corrosion tests, and 10 10 mm for electrochemical measurements. The specimens were grounded with SiC abrasive paper. Before the tests, specimens were cleaned in highly purified water and in ethanol using ultrasonic bath.Model solutions of 1 molm-3 NaCl (NaS), 0.5 molm-3 MgCl2 (MgS), and 0.5 molm-3 ZnCl2 (ZnS) were used in this experiment. The pH of the model solutions was maintained at around neutral.Electrochemical tests were carried out in a three-electrode cell using a potentiostat. An 4 cm2 Pt plate and an Ag/AgCl-saturated KCl electrode were used as the counter and the reference electrodes. Before the measurements, the specimens were immersed in the solutions for 3.6 ks (1 h) at 298 K. Electrochemical impedance spectroscopy (EIS) tests were carried out in the frequency range from 1 mHz to 10 kHz, and the modulation amplitude of the applied sinusoidal wave was 10 mV.Specimens were immersed in the model freshwater for 2.59 Ms (30 d) and 0.6 Ms (7 d) at 25 ºC. The mass of a specimen was measured before and after the test. Surface analysis were carried out by scanning electron microscope (SEM) and X-ray photoelectron spectroscope (XPS). Results From the immersion tests, the mass of specimens increased after immersion in the solutions and corrosion behavior of aluminum alloys was changed with the metal cations present in the solutions. Independent of used alloy, SEM images clearly showed the deposited corrosion products on the surface. Uniform deposition of corrosion products was observed on the specimen immersed in ZnS as compared to the NaS and MgS. EDS results demonstrated the presence of zinc-related products on the specimen immersed in ZnS XPS results suggested that zinc ions were incorporated in the oxide films of aluminum alloy and increased the corrosion resistance property of the oxide films. EIS results showed the highest impedance in ZnS as compared to the other solutions. References 1) T. H. Nguyen and R. T. Foley, Journal of the Electrochemical Society, 127, 2563-2566 (1980).2) R. T. Foley, Corrosion, 42, 277-288 (1986).3) B. Zaid, D. Saidi, A. Benzaid, and S. Hadji, Corrosion Science, 50, 1841-1847 (2008).4) Editorial board of Japan Aluminium Association: "Aluminum Handbook. Tokyo", Japan Aluminium Association, (2007), p 73.5) K. Otani, M. Sakairi, T. Kikuchi, and A. Kaneko, Zairyo-to-Kankyo, 59, 330-331(2010).6) M. Sakairi, K. Otani, A. Kaneko, Y. Seki, and D. Nagasawa, Surface and Interface Analysis, 45, 1517-1521 (2013).7) K. Otani, M. Sakairi, R. Sasaki, A. Kaneko, Y. Seki and D. Nagasawa, Journal of Solid State Electrochemistry, 18, 325-332 (2014).8) K. Otani, Md. Saiful Islam, M. Sakairi, and A. Kaneko, Surface and Interface Analysis, 51, 1207-1213 (2019).

Pengaruh Rapat Arus Proses Continuous Hard Anodizing Elektrolit (H2SO4) terhadap Laju Korosi Pipa Aluminium 6061 dengan Pengujian Kabut Garam

Anodizing is an electro-chemical process used to coat metal surfaces with a stable oxide layer. The function of this oxide layer is to increase corrosion resistance. The purpose of this study is determine the effect of variations in current density on the continuous hard anodizing process carried out in sulfuric acid electrolyte solution (H2SO4) on the corrosion rate of aluminum alloy 6061. Corrosion rate testing is carried out through salt fog testing. The values of the current variation used are 1 A/dm2; 2 A/dm2; 3 A/dm2; 4 A/dm2; and 5 A/dm2. Statistical calculations using the analysis of variance proved the current density in the anodizing process has a significant effect on the corrosion resistance of the anodizing workpiece. Corrosion testing provides information that the highest corrosion rate is an anodizing workpiece with a current density of 1 A/dm2, which is 125.6861 mdd, then 2 A/dm2 of 104.33333 mdd. The lowest corrosion rate value obtained at the use of current density 3 A/dm2, that is 51,8083 mdd. Meanwhile, the use of current density of 4 A/dm2 has a slightly higher corrosion rate compared to the use of current density of 3 A/dm2, which is 86.5444 mdd. Furthermore, the use of current density of 5 A/dm2 has the highest decay rate, so that the formed oxide layer will be damaged, as seen from the higher corrosion rate of the material, which is 100.8361 mdd.

Corrosion Study of Aluminum Alloy 3303 in Water-Ethylene Glycol Mixture: Effect of Inhibitors and Thermal Shocking

Three types of corrosion inhibitors consisting of sodium diphosphate (Na2H2P2O7), sodium benzoate (NaC7H5O2), and sodium tetraborate (Na2B4O7) were evaluated to analyze their effectiveness to inhibit the aluminum alloy 3303 (UNS A93303) against corrosion, in water-ethylene glycol (C2H6O2) mixture. Potentiodynamic polarization tests were carried out to study the effect of each chemical. The temperature of solutions was 88°C and the aluminum samples were coupled with five other metals consisting of mild steel, stainless steel, brass, copper, and solder to include the effect of galvanic corrosion. The results showed that sodium diphosphate can effectively protect the aluminum alloy 3303 in comparison with two other chemicals. The effect of thermal shocking on the corrosivity of water-ethylene glycol solution was also investigated. It was indicated that the corrosivity of water-ethylene glycol solution increases because of thermal shocking, which oxidizes the aqueous ethylene glycol. The corrosion rate of aluminum alloy 3303 coupled with the five metals in thermal shocked water-ethylene glycol solution is 142 mpy, while it is 94 mpy in fresh water-ethylene glycol solution.

Optimization of effective processing parameters of hybrid anti-corrosion Si/Zr sol–gel coatings doped with cerium salt for aluminum alloy 6061

In this study, the Taguchi method was used to design of experiment to obtain optimum conditions for hybrid Si–Zr sol–gel coating doped with cerium nitrate. The experimental design consisted of five different parameters at four levels. An orthogonal array of L16 type was utilized. With these experiences it was intended to find the suitable sol–gel deposition conditions for the aluminum alloy 6061. Chemical composition of the hybrid films were studied by attenuated total reflectance-fourier transform infrared spectroscopy. Field emission scanning electron microscopy was used to investigate the structural feature of coatings. Corrosion performance of coatings was evaluated by potentiodynamic polarization test. The response parameter of hybrid coatings was measured in terms of corrosion rate. The optimum processing parameters were predicted on the basis of data analysis and S/N ratio using analysis of variance. The results showed that by using optimal experimental parameters, the corrosion rate of aluminum alloy 6061 was decreased five orders of magnitude in compare to uncoated alloy 6061. This study has been based on design and optimizing effective parameters of hybrid organic-inorganic Si-Zr coatings doped with cerium reagent by Taguchi method. The effect of molar ratio of Si-bearing precursor, Zr content, Ce content, curing temperature and time was evaluated on corrosion rate of substrate. By deposition of the coatings on AA6061 the corrosion rate was decreased up to four orders of magnitude. Preparation of optimum coating led to decreasing in corrosion rate five orders of magnitude.

Protection against Corrosion of Aluminum Alloy in Marine Environment by Lawsonia inermis

The corrosion performance of aluminum alloy 5083 (AA5083) was investigated in the splash zone area simulated in salt spray cabinet at ambient temperature. Three paint formulations were prepared in accordance with different percentages of henna extract. FTIR method was used to determine the constituent of henna while weight loss and electrochemical method were applied to investigate the inhibition behaviour. The findings show that corrosion rate of aluminum alloy decreased with the increases of henna extract in the coating formulation. The rise of charge transfer resistance (Rct) value has contributed to the greater protection of the coated aluminum. The decrease in double layer capacitance value (Cdl) is another indicator that a better protective barrier has been formed in the presence of henna in the coating matrix.

The Research Progress of Aluminum Alloy Corrosion in Marine Atmosphere

It is very important to study on the corrosion of aluminum in marine atmospheric environment, because aluminum alloy structure of weapon equipment usually serves in marine atmospheric environment. On the basis of marine atmospheric environment corrosion features, the paper summarizes the influence of marine atmospheric environment influencing factors (e.g., Relative Humidity, Concentration of cl-, Alternate Drying-Wetting, Rainfall) on corrosion rule and corrosion rate of aluminum alloy, and analyses the mechanism of pitting, inter-granular corrosion and denudation. Then the natural environment exposure test and accelerated test were compared. Finally, the key research direction in the field of aluminum alloy corrosion in marine atmosphere was pointed out.

Investigation on corrosion behaviors of aluminum alloy in NaCl and EXCO solution

Purpose – The purpose of this paper is to investigate the corrosion behaviors of 2A12 aluminum alloy in NaCl and EXCO solution, and establish the relationship between the corrosion depth and the time. Design/methodology/approach – Alternate immersion corrosion test chamber was used to perform the corrosion test. The corrosion mediums were 3.5 percent NaCl solution and EXCO solution (NaCl 234 g/L, KNO3 50 g/L, 68 percent HNO3 6.8 mL/L). The surface morphology was studied using the digital microscope. Findings – The average corrosion rate of aluminum alloy in NaCl solution decreased gradually at the initial stage and then went to a plateau value. The average corrosion rate of aluminum alloy in EXCO solution increased first, then showed a downward trend. The empirical function D=At B was verified. Originality/value – The results could provide a reference for the establishment of accelerated environmental spectrum in the laboratory and give instructions on the application of aluminum alloy in alternated dry and wet environment.

Inhibitive Action of Ferrous Gluconate on Aluminum Alloy in Saline Environment

The corrosion of aluminum in saline environment in the presence of ferrous gluconate was studied using weight loss and linear polarization methods. The corrosion rates were studied in different concentrations of ferrous gluconate 0.5, 1.0, 1.5, and 2.0 g/mL at 28°C. Experimental results revealed that ferrous gluconate in saline environment reduced the corrosion rate of aluminum alloy at the different concentrations studied. The minimum inhibition efficiency was obtained at 1.5 g/mL concentration of inhibitor while the optimum inhibition efficiency was achieved with 1.0 g/mL inhibitor concentration. The results showed that adsorption of ferrous gluconate on the aluminium alloy surface fits Langmuir adsorption isotherm. The potentiodynamic polarization results showed that ferrous gluconate is a mixed type inhibitor. Ferrous gluconate acted as an effective inhibitor for aluminium alloy within the temperature and concentration range studied. The data obtained from weight loss and potentiodynamic polarization methods were in good agreement.

An investigation of the effects of inorganic inhibitors on the corrosion rate of aluminum alloy using electrochemical noise measurements and electrochemical impedance spectroscopy

PurposeThe purpose of this paper is to investigate the effects of inorganic inhibitors on the corrosion rate of aluminum alloy using the electrochemical noise (EN) analysis and electrochemical impedance spectroscopy (EIS) techniques.Design/methodology/approachEN and EIS measurements were employed to study the corrosion behavior of aluminum alloy in Na2SO4(0.50 M)/NaCl(0.20 M) solution in presence of inorganic inhibitors. The time‐series noise patterns were transformed into the frequency domain using fast Fourier transformation, and then their power spectrum densities (PSDs) at specified frequencies were determined and compared with the EIS and polarization results.FindingsThe EN, EIS and polarization results were in agreement. The inhibitive effect of the anions decreased in the order: CrO42−>Cr2O72−>NO3−>WO42−>MoO42−>NO2−. The results showed that the slope of PSD of the current (i.e. the “roll off”) was less where inhibition efficiency was greater. The spectral noise impedance and the modulus of the impedance recorded using impedance spectroscopy showed good agreement.Originality/valueThis paper provides useful information relative to corrosion inhibition efficiency of the sodium and potassium salts using EN analysis technique.

流動塩化ナトリウム水溶液中におけるアルミニウム合金の腐食速度

流動塩化ナトリウム水溶液中におけるアルミニウム合金の腐食速度