Evaluation of Mycocorrosion by Amorphotheca resinae in Aluminum Alloys 2024, 7075, 5083 and 3105: A Comprehensive Study

Evaluation of Mycocorrosion by Amorphotheca resinae in Aluminum Alloys 2024, 7075, 5083 and 3105: A Comprehensive Study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Evaluation of Mycocorrosion by Amorphotheca resinae in Aluminum Alloys 2024, 7075, 5083 and 3105: A Comprehensive Study Amir Hosein Shariat, Hamid Moghimi, Minoo Giyahchi, Mohammad-Bagher Ebrahim-Habibi, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4291481/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 17 Aug, 2024 Read the published version in Scientific Reports → Version 1 posted 10 You are reading this latest preprint version Abstract 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. Biological sciences/Biological techniques Biological sciences/Biotechnology Biological sciences/Microbiology Aluminium alloys Amorphotheca resinae Corrosion Mycocorrosion Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction The ISO 8044 standard defines corrosion as an electrochemical interaction that occurs reciprocally between a metal and its surroundings and results in changes to the metal's properties. When the effect of microorganisms carries out this process, it is assigned to microbial corrosion, a significant issue in many industries and sectors [ 1 , 2 ]. According to estimates, microbial corrosion losses account for 20–40% of all corrosion types, causing billions of dollars in economic scathe [ 3 ]. The process of microbial corrosion on metals, including aluminium, iron, copper, etc., and their alloys is carried out by various microorganisms, and fungi are among the significant ones in corrosion [ 4 ]. Aspergillus niger , Fusarium spp., Penicillium spp., and Amorphotheca resinae are some of the fungal species that contribute to microbial corrosion; A. resinae is the most significant and harmful fungus in corrosion among others [ 5 ] as it corrodes aluminum fuel tanks and is resistant to hostile environments thanks to the abundance of spores it produces [ 5 , 6 ]. Among the variety of carbon sources, diesel, and jet fuel could serve as the carbon supply for A. resinae . This fungus typically comes into contact with sediments and the aqueous phase of fuel and water combinations [ 7 ] and generates organic acids as a result of hydrocarbon consumption which is the principle of how the fungus causes corrosion on metal surfaces, including aluminium. In contrast to alkaline and neutral settings, acidic conditions are more likely to cause aluminum to corrode, and fungi's production of organic acids increases both the acidity of the environment and the rate of corrosion [ 8 , 9 ]. Due to characteristics like lightweight, repeatability, ease of work, durability, rust resistance, forming ability, and electrical conductivity, aluminum -the second most used metal- has become valuable and widely employed [ 10 ]. Heat exchangers, hospital equipment, automotive parts, etc. are made of aluminum alloy 3105 [ 11 ], while the 2024 aluminum alloy is utilized in the manufacture of airplanes, fuel tanks, auto parts, and other machinery [ 12 ]. The aluminum alloy 5083 is frequently used in marine equipment, pressure and storage tanks, constructions, and aircraft sectors, but in situations with a lot of power requirements, 7075 aluminum alloy is employed [ 13 ]. The majority of studies in the field of microbial corrosion on aluminum alloys have exclusively focused on the corrosion of Aspergillus species, A. resinae , and some bacterial genera, including Bacillus and Pseudomonas [ 14 ]. Although studies on A. resinae's ability to corrode aluminum alloy 2024 have been conducted before, to the best of our knowledge, there is no comparative research on the intensity of A. resinae’ s mediated corrosion on different kinds of widely used aluminum alloys. Considering the widespread use of these alloys in various industries and their susceptibility to corrosion, having an overview of how this agent will influence these alloys sounds essential. As a result, this study aimed to examine the A. resinae corrosion rates in the aluminum alloys 2024, 7075, 5083, and 3105, analyzing how A. resinae affects their corrosion. Material and methods Strain and growth medium A. resinae DSM1203 was obtained from the Research Institute of Petroleum Industry (Iran) and used as the corrosive fungal strain in this experiment. Potato Dextrose Broth (PDB) culture medium (pH 6.5) was used to cultivate A. resinae during the examination process [ 15 ]. Preparation and immersion test The corrosion rate was calculated using the immersion method test, a graph of weight loss over time was drawn, and the graph's slope was used to determine the corrosion rate. For this examination, A7075, A5083, A2024, and A3105 alloys were obtained in the coupon shape (Produced by Mirab Sanat Rastin Pars in Iran). A three-millimeter hole was made on one side of the metals for immersion in the culture medium. The exact diameter and thickness of the coupons were measured using a caliper with an accuracy of 0.01 mm. Since the entire surface of the metals was not exposed to the corrosive environment, the diameter of the disposable area was measured. For sample preparation, coupons bearing the numbers 120, 280, 600, and 1200 were polished using silicone sandpaper under a gentle flow of water. The coupon samples were hung into the flasks and incubated in an inoculated liquid culture. To mimic the fuel tank's condition, 25 mL of diesel fuel was added to the culture medium which makes a diesel-aqueous two-phasic media. The incubation was carried out in static condition at 30 ºC for optimal growth but briefly shaken every few days to inhibit the aqueous phase from becoming anaerobic. After incubation, the physical structural changes of the alloys, corrosion rates, microbial growth, and biofilm thickness were analyzed in samples through different assessments, including pH changes, Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS), Electrochemical Impedance (EIS) measurement, 3D profilometry, and Confocal Laser Scanning Microscopy (CLSM). Following that, the samples were cleaned, and the weight loss (%) was assessed [ 16 ]. SEM and EDS analysis Following three aforementioned intervals, SEM (VEGA3 TESCAN, Czech Republic) and EDS (DXR-X10P DIGITAL-X-RAY-PRICESSOR) tests were conducted. The alloys were removed from the culture media and fixed with glutaraldehyde for 24 hours, then washed in five ethanol dilution series (25, 50, 75, 96, and 100%) in turn (2 h each). The fixed samples were then coated with a thin layer of gold and observed for any sign of corrosion and microbial biofilm formation. CLSM analysis CLSM (Leica, Germany) was implemented to trace biofilm on coupon surfaces in 3D resolution. To prepare the samples, the alloys went through the acridine orange staining. This fluorochrome dye attaches to the DNA of cells and shows a green hue under CLSM [ 17 ]. 3D profilometry 3D profilometry analysis was carried out to demonstrate the physical destruction intensity of alloys after mycocorrosion. The size of the pits on the coupon's surface will reveal the depth of microbial invasion and corrosion. The test was done after washing the aluminum coupons in a 3D profilometer (LPM-D2, Iran) and the data was analyzed by Gwyddion v.2.41 software. EIS analysis The coupon samples were put into a beaker (as a tube) that had a capacity of around 70 ml, exposing a particular 1.5 cm 2 region of the samples' surface to the electrolyte. In this investigation, Saturated Calomel Electrodes (SCE) were employed as the reference and the examined alloys served as the working electrodes. A platinum electrode with a surface area of 1 cm 2 served as the counter electrode. The time constant is represented by the peak that was seen in the phase angle diagram for every sample. The surface and corrosion rates were investigated using the EIS test. In this experiment, a frequency analyzer of the Solarton-SI 1260 type and a potentiostat of the Solarton-SI 1287 type were used. ZsimpWin v.3.60 software was utilized to compare the experiment's outcomes. Coupons weight loss (%) measurement Loss of the weight is a sign of the physical destruction during corrosion. To measure this parameter, the metals were eradicated from biofilm, the corrosion products, and sediments according to the ASTM G1-03 (American Society for Testing and Materials) standard. Then, the coupons were dehumidified at 50°C for 4 h and reached a constant dry weight. Finally, the weight loss rate was calculated in mL year − 1 by the Eq. (1) [ 18 ]: (1) CR \(=\frac{\mathbf{K}\times \mathbf{W}\left(\mathbf{g}\mathbf{r}\right)}{\mathbf{D} \left(\frac{\mathbf{g}\mathbf{r}}{{\varvec{c}\varvec{m}}^{3}}\right)\times \mathbf{A} \left({\mathbf{c}\mathbf{m}}^{2}\right)\times \mathbf{T}\left(\mathbf{h}\right)}\) Where K is the corrosion rate constant, A is the entire exposed area of ​​the coupon, T is the time the coupon samples were exposed to the corrosive solution, W is weight loss, and D is the metal coupon density. Statistical analysis All the quantitative tests were performed in triplicate and analyzed with SPSS v.27.0.1 software. The p-value was < 0.001. Results and Discussion pH variation in the corrosion process of aluminum coupons Prior to the commencement of the experiment, the pH value of the 2024 alloy was 6.6. Its values were 5.5 on the 25th day of inoculation, 4.85 on the 50th day, and 6.45 on the 75th day. In contrast, the control sample's values ranged from 6.26 to 5.83. The A. resinae fungus is able to synthesize organic acids, including citric, oxalic, succinic, glutaric, and pyruvic acids this ability could be the reason for the pH values decrement on days 25 and 50 [ 5 , 10 ]. Additionally, it is expected that the fungus will transit from its constant growth phase to the stage of cell death or lysis due to the reduction of carbon resources and mineral components in the culture media, which may be the cause of the increase in pH values on day 75. Alkaline metabolite synthesis is linked to this phase shift [ 19 ]. In several alloys, comparable outcomes were seen. On days 25, 50, and 75, the pH values of the 7075 alloy were 5.54, 4.93, and 6.38, respectively. The pH values of alloy 5083 were likewise 5.70, 5.3, and 6.48, in that order, while for alloy 3105 the values were likewise 5.62, 5.35, and 6.62 in the same periods. It is worth noting, that for each of the four alloys under consideration, the control samples' pH value range was nearly identical. Weight loss in the corrosion process of aluminum coupons The results of the corrosion rate ratio in the presence and absence of A. resinae are shown in Table 2 . The findings demonstrated that the samples' corrosion rates in A. resinae culture are noticeably higher than that of the sterile solution (control) with increasing exposure duration, revealing that the presence of this fungus can speed up alloy corrosion [ 20 ]. The samples with the highest and lowest rates of corrosion were 2024 and 3105, respectively. The ratio of the corrosion rate for all the samples on day 50 was at its highest value and for the entire test period, the 2024 sample's corrosion rate was reduced by 1.6, 2.2, and 2.4 times more than that of the control. Samples 5083 and 3105 did not show measurable corrosion on the 25th day, but the ratios after 50 and 75 days, were gradually increased by 1.8 and 7.1 times in sample 5083 and 2 and 9.1 times in sample 3105 (Fig. 1 ). The corrosion rates of the 2024 alloy were 1.3417, 0.6655, and 0.8393 on days 25, 50, and 75, respectively. This is significantly greater than the corrosion rates of the alloy 3105, with 0.2442, and 0.1493 on days 50 and 75. On day 75, alloy 2024 also lost 7 mg of its weight, which is far greater than alloy 3105's with 2 mg of weight reduction. Table 1 The weight loss and corrosion rate of aluminum alloys in the test period of 25-50-75 days Time (days) Alloy Code Initial weight (g) Second weight (g) Weight loss (mg) Corrosion rate (mpy) Control to Test Ratio Control Test Control Test Control Test Control Test 25 2024 2.983 3.281 2.982 3.279 1 2 0.2104 1.3417 1.6232 3105 0.573 1.246 0.573 1.246 0 0 0 0 0 5083 2.508 2.684 2.508 2.684 0 0 0 0 0 7075 1.733 2.212 1.732 2.211 1.222 1 0.1601 0.2181 1.3547 50 2024 2.327 2.567 2.325 2.562 2 1 0.2994 0.6655 2.2228 3105 1.145 1.071 1.144 1.070 1 1 0.1195 0.2442 2.04355 5083 2.136 2.668 2.135 2.665 1 3 0.1941 0.3496 1.8011 7075 1.748 1.876 1.746 1.873 2 3 0.2718 0.4691 1.7259 75 2024 2.282 2.437 2.279 2.430 3 7 0.3532 0.8393 2.3763 3105 0.893 1.200 0.892 1.198 1 2 0.0795 0.1493 1.8779 5083 2.615 2.035 2.613 2.032 2 3 0.2263 0.3873 1.7321 7075 1.899 1.838 1.897 1.834 2 4 0.2319 0.5284 2.7563 In general, the results indicated that the tendency to corrosion and the corrosion rate increased gradually [ 21 ]. This could be because of the gradual production of organic acids, reaching their maximum concentration between days 25 to 50 [ 22 ]. Compared to the 75th day which is based on the identical results of Brenda Little et al. (2009), entering the fungus to death and lysis phase, the pH is lowered and corrosion is reduced [ 19 ]. Also, the resistance of aluminum in neutral and alkaline pH environments to corrosion could be another factor that lowers the corrosion rate on day 75 [ 23 ]. A. resinae destroys the oxide film layer that is naturally formed on the aluminum surface which has a protective effect against corrosion. This will cause more corrosion of the samples [ 21 ]. While in sterile environments due to the existence of this oxide layer, the tendency of aluminum to corrode is very weak [ 8 , 24 , 25 ]. The obtained results showed that the 2024 and 3105 alloys had the lowest and highest corrosion resistance, respectively which is consistent with the reports of Imo et al.’s (2018) and Sun et al.’s (2009) studies [ 26 , 27 ]. A. resinae is aerobic and consumes large amounts of dissolved oxygen in the culture medium. This phenomenon is significant in deep layers of the biofilm structure, leading to the creation of an anaerobic niche over there. This area also accumulates enormous amounts of organic acids by trapping them into rigid layers of biofilm structure. These events create two separated regions with different gradients of oxygen; The aerated area which acts as the anode and the non-aerated (anaerobic) area as the cathode [ 28 ]. By creating an oxygen-concentrated region, the aluminum oxide layer is destroyed and causes localized corrosion and the release of Al 3+ [ 29 ]. As explained in the results of weight loss (Table 1 ), with the increase of the test time, the number of holes on the surface of the samples in the biotic solution gradually increases, which shows that the corrosion of aluminum alloys by the A. resinae is mainly the result of localized cavities. Because some of the holes will link to form larger ones, aluminum alloys' mechanical qualities and lifetime of use are decreased [ 21 ]. As per the obtained results, sample 3015 has the strongest corrosion resistance and the lowest corrosion rate, corresponding to Imo et al. (2018) [ 26 ] and Sun et al. (2009) [ 27 ]; alloy 2024 has the lowest corrosion resistance. Corrosion evaluation by SEM To examine how fungus adhered to metal surfaces and to spot corrosion, SEM micrographs were obtained after the test period of 25, 50, and 75 days (see Fig. 2 ). In images a2 to d2, the biofilm and fungal hyphae on the coupons surfaces are visible, which in the case of sample 7075 is very compact and sticky. Figure 2c3 shows the gathered hyphae and spores inside the cavity on the surface of sample 5083 and in a3 to d3 micrographs, intense local holes are obvious. The average diameter of holes was 8.08, 2.46, 9.05, and 5.13 µm in 2024, 7075, 3105, and 5083 alloys, respectively (Fig. a 4 to c 4 ). Although the 3105 sample had the highest average diameter of holes, the corrosion of this sample was insignificant. That may be the reason for surficial corrosion in which the holes of corrosion were not very deep. The SEM images of aluminum alloys revealed that the shape and diameter of the corrosion holes in the fungal environment varied. This difference may be attributed to the non-uniform growth of the fungus in the initial stages of development, as well as the accumulation of biofilm in distinct regions of the aluminum samples, resulting in uneven distribution of the corrosion holes. Some corrosion products were observed on the surface of samples a2, b3, c2, and d3, and with an increasing incubation period, more intense fungal hyphae and spores on the aluminum surface were obvious and expected. This intensity could cause local corrosion which is shown in Fig. a 4 to d 4 . The results obtained from the preliminary weight loss and SEM analysis revealed that alloy 2024 has a high sensitivity to corrosion even when there is no fungus. Corrosion evaluation by EDS The proportion of elements in a sample may be determined using the EDS method. Based on these results, Mg, O, C, and Al elements were detected in EDS spectra (see Supplementary Fig. S1 online) of the cultivated aluminum alloys, while Cl, S, Na, and Cu were present at lower intensity. As Zhang et al. (2022) demonstrated, the presence of O and C elements can be attributed to fungal hyphae and spores, which can confirm the growth of fungal biofilm on the surface of the samples [ 8 ]. According to the results of EDS (Table 2 ), the relative weight percentage (Wt.%) of Al in the corrosion products was the highest among the other compounds. The reason could be quested in the presence of A. resinae that accelerates the dissolution of aluminum due to biofilm adhesion. The longer the fungus is present, the more aluminum is deposited as Alekhova et al. (2010) and Fan et al. (2021) mentioned in their reports [ 21 , 30 ]. Some aluminum alloy elements such as Mg may increase the growth of the fungus to some extent [ 31 ]. Of the elements that comprise the 2024 alloy, Cu has the highest concentration. According to the findings of Buchheit et al. (2000), the presence of Cu ions is common in the vicinity of corrosion-mediated holes. So, the high degree of corrosion is directly related to the presence of the Cu element in the corrosion products, which are discharged along with the alloy. Spherical compounds observed near the holes are assigned to copper deposits from the dealloying process, and chlorine is also observed along with them [ 32 ]. Table 2 Quantitative results of EDS analysis for tested alloys per unit (wt.%) Alloy Al C O Na Mg Cu Cl S 2024 55.20 19.97 16.20 - 1.07 6.79 0.77 - 3105 49.36 30.54 14.33 1.95 1.52 - - 2.29 5083 46.86 34.93 16.86 - 0.69 - 0.67 - 7075 48.43 37.96 10.68 0.34 0.68 - - 1.90 Corrosion evaluation by EIS Corrosion resistance and corrosion rate were checked using the EIS test. The structure of the fungal biofilm, the activity of the fungus, and its metabolites can all have an impact on the electrochemical reaction that drives the microbial corrosion process in aluminum samples [ 33 ]. A semicircular diagram forms as a consequence of the growth of fungi and the production of fungal acid metabolites, followed by microbial adhesion to the sample surface and the build-up of corrosion products. It can be seen in Fig. 2 that samples 3105, 5083, 7075, and 2024 had the highest to lowest corrosion resistance, respectively. Sample 2024 had a resistance of 7138 Ω.cm², a lower value than the other samples’ resistance, while 3105 alloys had a resistance value of 1.12×10 5 Ω.cm², which was greater than that of the others. Additionally, it is evident that the magnitude of load transfer resistance (Rct), which indicates the value of metal resistance against metal ion was released which in the case of sample 3105 was about 15.6 times higher than that of 2024 alloy. In the Nyquist diagram, the diameter of each semicircular represents the corrosion resistance of each sample. According to this plot (Fig. 2 a), the semicircles' diameters were around 4000 Ω.cm² in 2024 alloy, 11000 Ω.cm² in 7075, 32000 Ω.cm² in 5083, and 40000 Ω.cm² in 3105 alloys. From these findings, it can be concluded that 3105 and 5083 alloys are more resistant to the dissolution of metal ions in the microbial environment, causing their resistance to corrosion in the same condition. As can be demonstrated, there is a respectable level of agreement between the results and the outcomes of the other tests, which shows that alloy 2024 has the highest and alloy 3105 has the lowest corrosion rates. According to the results of Fan et al., 2021, The Nyquist diagram's decreasing ring diameter during the incubation time indicates that A. resinae is adhered to the sample surface and generates acidic metabolites [ 21 ]. The number of loops (peaks) shows the number of time constants. High-frequency rings are created due to the capacity of the two electric layers formed between the oxide layer on the surface of the alloy and the solution, and these two electric layers are also called capacitive rings. Also, medium-frequency rings can be attributed to the loosening process of the oxide film. The results of the device are presented as point values ​​with a negative slope (Bode plot, Fig. 2 b), and as can be seen in Fig. 2 c, there is only one peak that shows the dissolution of the oxide layer on the alloys. 3D Profilometeric Analysis According to the results obtained from previous tests, 2024 and 3105 alloys had the highest and lowest corrosion rates, respectively (See Supplementary Fig. S2 online for the obvious corrosion pits on the surface of the alloys). Based on these results, CLSM and 3D profilometry tests were performed on these two samples to compare the efficiency of corrosion on them. Using a 3D profilometer, the configuration of the pits on the coupon surface was assessed. The results indicated that the pits in the 2024 alloy are deeper than in 3105 where the maximum corrosion depth in the 2024 alloy was equal to 480 µm compared to 61 µm in 3105. The pits' structure, depth, and width were also analyzed through this method, showing that in contrast to alloy 2024, which had long, narrow corrosion pits, alloy 3105 had shallower, rounder, and wider corrosion pits. The dippest pit was observed after 50 days of incubation in alloy 2024. These outcomes prove the results of weight loss measurement and EIS analysis. The values ​​of the results are shown in Fig. 3 , where the 3D figures and diagrams of the corroded areas of the surface of the samples are shown. The presence and percentage of some elements in the aluminum alloy component can be definitive to the severity of corrosion or in other words, the resistance of the metal to corrosion. For example, the amount of Mg in the 2024 alloy is less than 7075 and 5083 samples, and according to the investigation of Zhaohi et al. (2009), corrosion resistance increases with a higher amount of Al-Mg combination [ 34 , 35 ]. Also, the present and changing value of Cu can lead to a different corrosion rate. 2024 alloy has the highest amount of Cu. The results obtained by Min-Sung Hong et al. (2017) show that the negative effect of pitting corrosion is increased by the presence of this element [ 36 , 37 ] which is consistent with the results of this experiment. Corrosion evaluation by CLSM The CLSM technique was used to examine fungal biofilms, as well as how much biofilm was present in various areas of the surface after 50 days. In this test, the green color denotes the presence of fungal biofilm, and its intensity over the surface reveals how strongly the biofilm is adhered to the surface. Alloy 2024 had a more intense green color in its CLSM micrograph, while the irradiance was visibly lower in alloy 3105, indicating a thicker and more intense biofilm complex on the former alloy. These results are consistent with earlier research and indicate that alloy 2024 is more disposed to biofilm formation, which in turn increases the alloy's rate of corrosion. Conclusions Previous studies have shown that A. resinae can affect the corrosion of aluminum alloys which is related to the ability of this fungus to produce a wide range of metabolites and organic acids under aerobic conditions. These corrosive metabolites can change the chemical nature of the environment and the electrochemical properties of the metal, leading to metal corrosion. The present study has focused on comparing the rate, severity, and depth of the mycocorrosion developed by A. resinae on three aluminum alloys in 25-day intervals. Comparing the corrosion rate and resistance of the aluminum alloys, this experiment showed that alloys 2024 and 3105 had the highest and lowest corrosion rate, respectively. From the electrochemical analysis of impedance, it was found that the presence of fungus affected the metal's resistance to corrosion, and the resistance values of the samples in alloys 2024, 7075, 5083, and 3105 were respectively the lowest to the highest. These values were supported by outcomes of the microscopic observations in the CLSM analysis in which the intensity of biofilm formation on the 2024 alloy's surface was obviously higher than the most resistant alloy of the experiment (3105). The findings also confirmed that the intensity and depth of corrosion increases over time, as does the release of corrosion by-products, and the thickness and hardness of the biofilm. The observations and comparison results of this study can provide a better view to aluminum-using industries in order to accurately select the type of alloy depending on the corrosion resistance of each one. Declarations Ethics approval and consent to participate Ethics approval is not applicable as this article does not describe any studies involving human participants or animals. Consent for publication Not applicable. Availability of data and materials All data are included in the manuscript and additional information, and further queries about sharing data can be directed to the corresponding author. Competing interests The authors declare that they have no competing interests. Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Authors’ contributions H.M. designed the project. A.H.S performed the experiments, A.H.S and M.G. wrote the paper, and M.E., M.G., and H.T. edited the manuscript. 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Localized corrosion of aluminum alloy 6061 in the presence of Aspergillus niger. International Biodeterioration & Biodegradation 133 , 17-25 (2018). Alekhova, T. et al. Electron microscopy investigation of AlMg6 aluminum alloy surface defects caused by microorganisms extracted in space stations. Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques 4 , 747-753 (2010). Wang, J. et al. Corrosion behavior of Aspergillus niger on 7075 aluminum alloy and the inhibition effect of zinc pyrithione biocide. Journal of The Electrochemical Society 166 , G39 (2019). Buchheit, R., Martinez, M. & Montes, L. Evidence for Cu ion formation by dissolution and dealloying the Al2CuMg intermetallic compound in rotating ring‐disk collection experiments. Journal of the Electrochemical Society 147 , 119 (2000). Lekbach, Y. et al. in Advances in microbial physiology Vol. 78 317-390 (Elsevier, 2021). Wen, Z., Wu, C., Dai, C. & Yang, F. Corrosion behaviors of Mg and its alloys with different Al contents in a modified simulated body fluid. Journal of Alloys and Compounds 488 , 392-399 (2009). Lim, J. et al. Controlled optimization of Mg and Zn in Al alloys for improved corrosion resistance via uniform corrosion. Materials Advances 3 , 4813-4823 (2022). Hong, M.-S., Park, I.-J. & Kim, J.-G. Alloying effect of copper concentration on the localized corrosion of aluminum alloy for heat exchanger tube. Metals and Materials International 23 , 708-714 (2017). Ahmed, M. S., Anwar, M. S., Islam, M. S. & Arifuzzaman, M. Experimental study on the effects of three alloying elements on the mechanical, corrosion and microstructural properties of aluminum alloys. Results in Materials 20 , 100485 (2023). Additional Declarations No competing interests reported. Supplementary Files SupplementaryfileShariatetal..docx Cite Share Download PDF Status: Published Journal Publication published 17 Aug, 2024 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 26 Jun, 2024 Reviews received at journal 12 Jun, 2024 Reviews received at journal 29 May, 2024 Reviewers agreed at journal 19 May, 2024 Reviewers agreed at journal 19 May, 2024 Reviewers invited by journal 19 May, 2024 Editor assigned by journal 19 May, 2024 Editor invited by journal 29 Apr, 2024 Submission checks completed at journal 25 Apr, 2024 First submitted to journal 19 Apr, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4291481","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":296847512,"identity":"260d3eeb-6207-4150-981c-e3de4be619a9","order_by":0,"name":"Amir Hosein Shariat","email":"","orcid":"","institution":"University of Tehran","correspondingAuthor":false,"prefix":"","firstName":"Amir","middleName":"Hosein","lastName":"Shariat","suffix":""},{"id":296847517,"identity":"9ff6298e-7f3b-46d7-a594-56cc1269a2a0","order_by":1,"name":"Hamid Moghimi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAtklEQVRIiWNgGAWjYBACAyBmBpI8/FABHuK1SDYwk6QFxDjATKTDzMUOH35dULBNxvhG/gGGHzUMMuYNBLRYzk5Ls55hcJvH7EYyA2PPMQYemQOEHHY7x8yYB6qFgbeBgUeCkMPgWoxnAG35S6QW48cgLQYSyQzMRNqSlsYM0iJx5rHBYZljEsRoST78mefPbXv+9sSHD9/U2NgT1AIEbHBFBxgYiNEAjMkPRCkbBaNgFIyCkQsA96M1rp57kd8AAAAASUVORK5CYII=","orcid":"","institution":"University of Tehran","correspondingAuthor":true,"prefix":"","firstName":"Hamid","middleName":"","lastName":"Moghimi","suffix":""},{"id":296847518,"identity":"4b91d756-8e1d-4ec2-8eef-ffda3fe3a4d3","order_by":2,"name":"Minoo Giyahchi","email":"","orcid":"","institution":"University of Tehran","correspondingAuthor":false,"prefix":"","firstName":"Minoo","middleName":"","lastName":"Giyahchi","suffix":""},{"id":296847519,"identity":"e0cb635e-8e85-47ef-99aa-1ee3340fc32d","order_by":3,"name":"Mohammad-Bagher Ebrahim-Habibi","email":"","orcid":"","institution":"Research Institute of Petroleum Industry","correspondingAuthor":false,"prefix":"","firstName":"Mohammad-Bagher","middleName":"","lastName":"Ebrahim-Habibi","suffix":""},{"id":296847520,"identity":"0c10a4ed-fed5-4815-9e56-320f95169f15","order_by":4,"name":"Hassan Tirandaz","email":"","orcid":"","institution":"Research Institute of Petroleum Industry","correspondingAuthor":false,"prefix":"","firstName":"Hassan","middleName":"","lastName":"Tirandaz","suffix":""}],"badges":[],"createdAt":"2024-04-19 07:15:32","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4291481/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4291481/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-024-70150-x","type":"published","date":"2024-08-17T15:57:21+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":55589066,"identity":"c55447f2-e2e1-4845-ab8b-64ca3e664224","added_by":"auto","created_at":"2024-04-30 09:16:37","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":2331738,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images of corroded and uncorroded aluminum alloys. \u003cstrong\u003ea1)\u003c/strong\u003e to \u003cstrong\u003ed1\u003c/strong\u003e) control samples without A. resinae.\u003cstrong\u003e a2)\u003c/strong\u003e to \u003cstrong\u003ed2\u003c/strong\u003e) samples after 25 days in the presence of A. resinae.\u003cstrong\u003e a3)\u003c/strong\u003e to \u003cstrong\u003ed3\u003c/strong\u003e) samples after 50 days in the presence of A. resinae. \u003cstrong\u003ea4)\u003c/strong\u003e to \u003cstrong\u003ed4\u003c/strong\u003e) samples after 75 days in the presence of A. resinae\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-4291481/v1/e38e375a2eef69861d76042f.png"},{"id":55588295,"identity":"9c3b4201-b322-4948-ac84-dfdde88c6e6d","added_by":"auto","created_at":"2024-04-30 09:08:37","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":263459,"visible":true,"origin":"","legend":"\u003cp\u003eDiagrams of resistance of four different alloys to corrosion. a) Nyquist diagram b) Bode diagram c) Phase angle diagram. The diameter of each semicircle shows the corrosion resistance of each sample.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-4291481/v1/35df9116d62f838a9ac74614.png"},{"id":55588293,"identity":"bbbf4999-7da4-41c6-ab69-2c76542a0d6a","added_by":"auto","created_at":"2024-04-30 09:08:37","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1127120,"visible":true,"origin":"","legend":"\u003cp\u003eThe 3D profilometer graph and diagrams of the corroded areas of the surface of aluminum alloy coupons with the structure of pits obtained from fungal biofilm corrosion after 50 days. 3D graph and Depth of \u003cstrong\u003ea)\u003c/strong\u003e 2024 alloy and \u003cstrong\u003eb)\u003c/strong\u003e 3105 alloy. The diagrams of the corroded areas of the surface of\u003cstrong\u003e c)\u003c/strong\u003e 2024 alloy and \u003cstrong\u003ed)\u003c/strong\u003e 3105 alloy\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-4291481/v1/8c635ebc05273d2d0ee833b6.png"},{"id":55588296,"identity":"06647ece-7e37-488f-a905-bc8432f3db2d","added_by":"auto","created_at":"2024-04-30 09:08:37","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1093562,"visible":true,"origin":"","legend":"\u003cp\u003eCLSM and 3D micrograph from the surface of the samples. The intensity of the fluorescence indicates the intensity of the formed biofilm. 3D micrographs of \u003cstrong\u003ea)\u003c/strong\u003e 2024 alloy and \u003cstrong\u003eb)\u003c/strong\u003e 3105 alloy. CLSM micrographs of\u003cstrong\u003e c)\u003c/strong\u003e 2024 alloy and \u003cstrong\u003ed)\u003c/strong\u003e 3105 alloy\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-4291481/v1/c10ccf29e3fe4d725821362f.png"},{"id":63070873,"identity":"4296030e-cb07-481c-bcdf-b677306882e4","added_by":"auto","created_at":"2024-08-22 19:56:02","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":6071113,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4291481/v1/a5b33df6-8b43-4807-a22b-248f7ef7c796.pdf"},{"id":55588297,"identity":"bd0ce09a-1caf-4b08-adb5-d0df8c22d185","added_by":"auto","created_at":"2024-04-30 09:08:38","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":3107461,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryfileShariatetal..docx","url":"https://assets-eu.researchsquare.com/files/rs-4291481/v1/e819e4cd8c54c9cc8d809b3f.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Evaluation of Mycocorrosion by Amorphotheca resinae in Aluminum Alloys 2024, 7075, 5083 and 3105: A Comprehensive Study","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe ISO 8044 standard defines corrosion as an electrochemical interaction that occurs reciprocally between a metal and its surroundings and results in changes to the metal's properties. When the effect of microorganisms carries out this process, it is assigned to microbial corrosion, a significant issue in many industries and sectors [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. According to estimates, microbial corrosion losses account for 20\u0026ndash;40% of all corrosion types, causing billions of dollars in economic scathe [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The process of microbial corrosion on metals, including aluminium, iron, copper, etc., and their alloys is carried out by various microorganisms, and fungi are among the significant ones in corrosion [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. \u003cem\u003eAspergillus niger\u003c/em\u003e, \u003cem\u003eFusarium\u003c/em\u003e spp., \u003cem\u003ePenicillium\u003c/em\u003e spp., and \u003cem\u003eAmorphotheca resinae\u003c/em\u003e are some of the fungal species that contribute to microbial corrosion; \u003cem\u003eA. resinae\u003c/em\u003e is the most significant and harmful fungus in corrosion among others [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] as it corrodes aluminum fuel tanks and is resistant to hostile environments thanks to the abundance of spores it produces [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAmong the variety of carbon sources, diesel, and jet fuel could serve as the carbon supply for \u003cem\u003eA. resinae\u003c/em\u003e. This fungus typically comes into contact with sediments and the aqueous phase of fuel and water combinations [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] and generates organic acids as a result of hydrocarbon consumption which is the principle of how the fungus causes corrosion on metal surfaces, including aluminium. In contrast to alkaline and neutral settings, acidic conditions are more likely to cause aluminum to corrode, and fungi's production of organic acids increases both the acidity of the environment and the rate of corrosion [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDue to characteristics like lightweight, repeatability, ease of work, durability, rust resistance, forming ability, and electrical conductivity, aluminum -the second most used metal- has become valuable and widely employed [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Heat exchangers, hospital equipment, automotive parts, etc. are made of aluminum alloy 3105 [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e], while the 2024 aluminum alloy is utilized in the manufacture of airplanes, fuel tanks, auto parts, and other machinery [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The aluminum alloy 5083 is frequently used in marine equipment, pressure and storage tanks, constructions, and aircraft sectors, but in situations with a lot of power requirements, 7075 aluminum alloy is employed [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe majority of studies in the field of microbial corrosion on aluminum alloys have exclusively focused on the corrosion of \u003cem\u003eAspergillus\u003c/em\u003e species, \u003cem\u003eA. resinae\u003c/em\u003e, and some bacterial genera, including \u003cem\u003eBacillus\u003c/em\u003e and \u003cem\u003ePseudomonas\u003c/em\u003e [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Although studies on \u003cem\u003eA. resinae's\u003c/em\u003e ability to corrode aluminum alloy 2024 have been conducted before, to the best of our knowledge, there is no comparative research on the intensity of \u003cem\u003eA. resinae\u0026rsquo;\u003c/em\u003es mediated corrosion on different kinds of widely used aluminum alloys. Considering the widespread use of these alloys in various industries and their susceptibility to corrosion, having an overview of how this agent will influence these alloys sounds essential. As a result, this study aimed to examine the \u003cem\u003eA. resinae\u003c/em\u003e corrosion rates in the aluminum alloys 2024, 7075, 5083, and 3105, analyzing how \u003cem\u003eA. resinae\u003c/em\u003e affects their corrosion.\u003c/p\u003e"},{"header":"Material and methods","content":"\u003cp\u003e \u003cb\u003eStrain and growth medium\u003c/b\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e \u003cem\u003eA. resinae\u003c/em\u003e DSM1203 was obtained from the Research Institute of Petroleum Industry (Iran) and used as the corrosive fungal strain in this experiment. Potato Dextrose Broth (PDB) culture medium (pH 6.5) was used to cultivate \u003cem\u003eA. resinae\u003c/em\u003e during the examination process [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePreparation and immersion test\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThe corrosion rate was calculated using the immersion method test, a graph of weight loss over time was drawn, and the graph's slope was used to determine the corrosion rate. For this examination, A7075, A5083, A2024, and A3105 alloys were obtained in the coupon shape (Produced by Mirab Sanat Rastin Pars in Iran). A three-millimeter hole was made on one side of the metals for immersion in the culture medium. The exact diameter and thickness of the coupons were measured using a caliper with an accuracy of 0.01 mm. Since the entire surface of the metals was not exposed to the corrosive environment, the diameter of the disposable area was measured.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003cp\u003eFor sample preparation, coupons bearing the numbers 120, 280, 600, and 1200 were polished using silicone sandpaper under a gentle flow of water. The coupon samples were hung into the flasks and incubated in an inoculated liquid culture. To mimic the fuel tank's condition, 25 mL of diesel fuel was added to the culture medium which makes a diesel-aqueous two-phasic media. The incubation was carried out in static condition at 30 \u0026ordm;C for optimal growth but briefly shaken every few days to inhibit the aqueous phase from becoming anaerobic. After incubation, the physical structural changes of the alloys, corrosion rates, microbial growth, and biofilm thickness were analyzed in samples through different assessments, including pH changes, Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS), Electrochemical Impedance (EIS) measurement, 3D profilometry, and Confocal Laser Scanning Microscopy (CLSM). Following that, the samples were cleaned, and the weight loss (%) was assessed [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eSEM and EDS analysis\u003c/h2\u003e \u003cp\u003eFollowing three aforementioned intervals, SEM (VEGA3 TESCAN, Czech Republic) and EDS (DXR-X10P DIGITAL-X-RAY-PRICESSOR) tests were conducted. The alloys were removed from the culture media and fixed with glutaraldehyde for 24 hours, then washed in five ethanol dilution series (25, 50, 75, 96, and 100%) in turn (2 h each). The fixed samples were then coated with a thin layer of gold and observed for any sign of corrosion and microbial biofilm formation.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eCLSM analysis\u003c/h2\u003e \u003cp\u003eCLSM (Leica, Germany) was implemented to trace biofilm on coupon surfaces in 3D resolution. To prepare the samples, the alloys went through the acridine orange staining. This fluorochrome dye attaches to the DNA of cells and shows a green hue under CLSM [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e3D profilometry\u003c/h2\u003e \u003cp\u003e3D profilometry analysis was carried out to demonstrate the physical destruction intensity of alloys after mycocorrosion. The size of the pits on the coupon's surface will reveal the depth of microbial invasion and corrosion. The test was done after washing the aluminum coupons in a 3D profilometer (LPM-D2, Iran) and the data was analyzed by Gwyddion v.2.41 software.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eEIS analysis\u003c/h2\u003e \u003cp\u003eThe coupon samples were put into a beaker (as a tube) that had a capacity of around 70 ml, exposing a particular 1.5 cm\u003csup\u003e2\u003c/sup\u003e region of the samples' surface to the electrolyte. In this investigation, Saturated Calomel Electrodes (SCE) were employed as the reference and the examined alloys served as the working electrodes. A platinum electrode with a surface area of 1 cm\u003csup\u003e2\u003c/sup\u003e served as the counter electrode. The time constant is represented by the peak that was seen in the phase angle diagram for every sample. The surface and corrosion rates were investigated using the EIS test. In this experiment, a frequency analyzer of the Solarton-SI 1260 type and a potentiostat of the Solarton-SI 1287 type were used. ZsimpWin v.3.60 software was utilized to compare the experiment's outcomes.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eCoupons weight loss (%) measurement\u003c/h2\u003e \u003cp\u003eLoss of the weight is a sign of the physical destruction during corrosion. To measure this parameter, the metals were eradicated from biofilm, the corrosion products, and sediments according to the ASTM G1-03 (American Society for Testing and Materials) standard. Then, the coupons were dehumidified at 50\u0026deg;C for 4 h and reached a constant dry weight. Finally, the weight loss rate was calculated in mL year \u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e by the Eq.\u0026nbsp;(1) [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]:\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e(1) CR \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(=\\frac{\\mathbf{K}\\times \\mathbf{W}\\left(\\mathbf{g}\\mathbf{r}\\right)}{\\mathbf{D} \\left(\\frac{\\mathbf{g}\\mathbf{r}}{{\\varvec{c}\\varvec{m}}^{3}}\\right)\\times \\mathbf{A} \\left({\\mathbf{c}\\mathbf{m}}^{2}\\right)\\times \\mathbf{T}\\left(\\mathbf{h}\\right)}\\)\u003c/span\u003e\u003c/span\u003e\u003c/h2\u003e \u003cp\u003eWhere K is the corrosion rate constant, A is the entire exposed area of ​​the coupon, T is the time the coupon samples were exposed to the corrosive solution, W is weight loss, and D is the metal coupon density.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eAll the quantitative tests were performed in triplicate and analyzed with SPSS v.27.0.1 software. The p-value was \u0026lt;\u0026thinsp;0.001.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results and Discussion","content":"\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003epH variation in the corrosion process of aluminum coupons\u003c/h2\u003e \u003cp\u003ePrior to the commencement of the experiment, the pH value of the 2024 alloy was 6.6. Its values were 5.5 on the 25th day of inoculation, 4.85 on the 50th day, and 6.45 on the 75th day. In contrast, the control sample's values ranged from 6.26 to 5.83. The \u003cem\u003eA. resinae\u003c/em\u003e fungus is able to synthesize organic acids, including citric, oxalic, succinic, glutaric, and pyruvic acids this ability could be the reason for the pH values decrement on days 25 and 50 [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Additionally, it is expected that the fungus will transit from its constant growth phase to the stage of cell death or lysis due to the reduction of carbon resources and mineral components in the culture media, which may be the cause of the increase in pH values on day 75. Alkaline metabolite synthesis is linked to this phase shift [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. In several alloys, comparable outcomes were seen. On days 25, 50, and 75, the pH values of the 7075 alloy were 5.54, 4.93, and 6.38, respectively. The pH values of alloy 5083 were likewise 5.70, 5.3, and 6.48, in that order, while for alloy 3105 the values were likewise 5.62, 5.35, and 6.62 in the same periods. It is worth noting, that for each of the four alloys under consideration, the control samples' pH value range was nearly identical.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eWeight loss in the corrosion process of aluminum coupons\u003c/h2\u003e \u003cp\u003eThe results of the corrosion rate ratio in the presence and absence of \u003cem\u003eA. resinae\u003c/em\u003e are shown in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The findings demonstrated that the samples' corrosion rates in \u003cem\u003eA. resinae\u003c/em\u003e culture are noticeably higher than that of the sterile solution (control) with increasing exposure duration, revealing that the presence of this fungus can speed up alloy corrosion [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. The samples with the highest and lowest rates of corrosion were 2024 and 3105, respectively. The ratio of the corrosion rate for all the samples on day 50 was at its highest value and for the entire test period, the 2024 sample's corrosion rate was reduced by 1.6, 2.2, and 2.4 times more than that of the control. Samples 5083 and 3105 did not show measurable corrosion on the 25th day, but the ratios after 50 and 75 days, were gradually increased by 1.8 and 7.1 times in sample 5083 and 2 and 9.1 times in sample 3105 (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The corrosion rates of the 2024 alloy were 1.3417, 0.6655, and 0.8393 on days 25, 50, and 75, respectively. This is significantly greater than the corrosion rates of the alloy 3105, with 0.2442, and 0.1493 on days 50 and 75. On day 75, alloy 2024 also lost 7 mg of its weight, which is far greater than alloy 3105's with 2 mg of weight reduction.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe weight loss and corrosion rate of aluminum alloys in the test period of 25-50-75 days\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"11\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTime (days)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eAlloy Code\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003eInitial weight (g)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003eSecond weight (g)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003eWeight loss (mg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003eCorrosion rate (mpy)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eControl to Test Ratio\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eControl\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTest\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eControl\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTest\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eControl\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eTest\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eControl\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eTest\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.983\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.281\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.982\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3.279\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.2104\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e1.3417\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e1.6232\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3105\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.573\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.246\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.573\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.246\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5083\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.508\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.684\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.508\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.684\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e 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colname=\"c7\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.1195\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.2442\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e2.04355\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5083\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.136\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.668\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.135\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.665\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.1941\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.3496\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e1.8011\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.748\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.876\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.746\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.873\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.2718\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.4691\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e1.7259\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.282\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.437\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.279\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.430\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.3532\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.8393\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e2.3763\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3105\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.893\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.892\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.198\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.0795\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.1493\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e1.8779\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5083\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.615\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.035\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.613\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.032\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.2263\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.3873\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e1.7321\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.899\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.838\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.897\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.834\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.2319\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.5284\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e2.7563\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eIn general, the results indicated that the tendency to corrosion and the corrosion rate increased gradually [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. This could be because of the gradual production of organic acids, reaching their maximum concentration between days 25 to 50 [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Compared to the 75th day which is based on the identical results of Brenda Little et al. (2009), entering the fungus to death and lysis phase, the pH is lowered and corrosion is reduced [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Also, the resistance of aluminum in neutral and alkaline pH environments to corrosion could be another factor that lowers the corrosion rate on day 75 [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. \u003cem\u003eA. resinae\u003c/em\u003e destroys the oxide film layer that is naturally formed on the aluminum surface which has a protective effect against corrosion. This will cause more corrosion of the samples [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. While in sterile environments due to the existence of this oxide layer, the tendency of aluminum to corrode is very weak [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. The obtained results showed that the 2024 and 3105 alloys had the lowest and highest corrosion resistance, respectively which is consistent with the reports of Imo et al.\u0026rsquo;s (2018) and Sun et al.\u0026rsquo;s (2009) studies [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cem\u003eA. resinae\u003c/em\u003e is aerobic and consumes large amounts of dissolved oxygen in the culture medium. This phenomenon is significant in deep layers of the biofilm structure, leading to the creation of an anaerobic niche over there. This area also accumulates enormous amounts of organic acids by trapping them into rigid layers of biofilm structure. These events create two separated regions with different gradients of oxygen; The aerated area which acts as the anode and the non-aerated (anaerobic) area as the cathode [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. By creating an oxygen-concentrated region, the aluminum oxide layer is destroyed and causes localized corrosion and the release of Al \u003csup\u003e3+\u003c/sup\u003e [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. As explained in the results of weight loss (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), with the increase of the test time, the number of holes on the surface of the samples in the biotic solution gradually increases, which shows that the corrosion of aluminum alloys by the \u003cem\u003eA. resinae\u003c/em\u003e is mainly the result of localized cavities. Because some of the holes will link to form larger ones, aluminum alloys' mechanical qualities and lifetime of use are decreased [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAs per the obtained results, sample 3015 has the strongest corrosion resistance and the lowest corrosion rate, corresponding to Imo et al. (2018) [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e] and Sun et al. (2009) [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]; alloy 2024 has the lowest corrosion resistance.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eCorrosion evaluation by SEM\u003c/h2\u003e \u003cp\u003eTo examine how fungus adhered to metal surfaces and to spot corrosion, SEM micrographs were obtained after the test period of 25, 50, and 75 days (see Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). In images a2 to d2, the biofilm and fungal hyphae on the coupons surfaces are visible, which in the case of sample 7075 is very compact and sticky. Figure\u0026nbsp;2c3 shows the gathered hyphae and spores inside the cavity on the surface of sample 5083 and in a3 to d3 micrographs, intense local holes are obvious. The average diameter of holes was 8.08, 2.46, 9.05, and 5.13 \u0026micro;m in 2024, 7075, 3105, and 5083 alloys, respectively (Fig. a\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e to c\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Although the 3105 sample had the highest average diameter of holes, the corrosion of this sample was insignificant. That may be the reason for surficial corrosion in which the holes of corrosion were not very deep. The SEM images of aluminum alloys revealed that the shape and diameter of the corrosion holes in the fungal environment varied. This difference may be attributed to the non-uniform growth of the fungus in the initial stages of development, as well as the accumulation of biofilm in distinct regions of the aluminum samples, resulting in uneven distribution of the corrosion holes. Some corrosion products were observed on the surface of samples a2, b3, c2, and d3, and with an increasing incubation period, more intense fungal hyphae and spores on the aluminum surface were obvious and expected. This intensity could cause local corrosion which is shown in Fig. a\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e to d\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The results obtained from the preliminary weight loss and SEM analysis revealed that alloy 2024 has a high sensitivity to corrosion even when there is no fungus.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eCorrosion evaluation by EDS\u003c/h2\u003e \u003cp\u003eThe proportion of elements in a sample may be determined using the EDS method. Based on these results, Mg, O, C, and Al elements were detected in EDS spectra (see Supplementary Fig. \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e online) of the cultivated aluminum alloys, while Cl, S, Na, and Cu were present at lower intensity. As Zhang et al. (2022) demonstrated, the presence of O and C elements can be attributed to fungal hyphae and spores, which can confirm the growth of fungal biofilm on the surface of the samples [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. According to the results of EDS (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), the relative weight percentage (Wt.%) of Al in the corrosion products was the highest among the other compounds. The reason could be quested in the presence of \u003cem\u003eA. resinae\u003c/em\u003e that accelerates the dissolution of aluminum due to biofilm adhesion. The longer the fungus is present, the more aluminum is deposited as Alekhova et al. (2010) and Fan et al. (2021) mentioned in their reports [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Some aluminum alloy elements such as Mg may increase the growth of the fungus to some extent [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. Of the elements that comprise the 2024 alloy, Cu has the highest concentration. According to the findings of Buchheit et al. (2000), the presence of Cu ions is common in the vicinity of corrosion-mediated holes. So, the high degree of corrosion is directly related to the presence of the Cu element in the corrosion products, which are discharged along with the alloy. Spherical compounds observed near the holes are assigned to copper deposits from the dealloying process, and chlorine is also observed along with them [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eQuantitative results of EDS analysis for tested alloys per unit (wt.%)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"9\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAlloy\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAl\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eO\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eNa\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eMg\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eCu\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eCl\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e55.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e19.97\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e16.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e6.79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3105\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e49.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e30.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2.29\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5083\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e46.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e34.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e16.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e48.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e37.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e10.68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1.90\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eCorrosion evaluation by EIS\u003c/h2\u003e \u003cp\u003eCorrosion resistance and corrosion rate were checked using the EIS test. The structure of the fungal biofilm, the activity of the fungus, and its metabolites can all have an impact on the electrochemical reaction that drives the microbial corrosion process in aluminum samples [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. A semicircular diagram forms as a consequence of the growth of fungi and the production of fungal acid metabolites, followed by microbial adhesion to the sample surface and the build-up of corrosion products. It can be seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e that samples 3105, 5083, 7075, and 2024 had the highest to lowest corrosion resistance, respectively. Sample 2024 had a resistance of 7138 Ω.cm\u0026sup2;, a lower value than the other samples\u0026rsquo; resistance, while 3105 alloys had a resistance value of 1.12\u0026times;10\u003csup\u003e5\u003c/sup\u003e Ω.cm\u0026sup2;, which was greater than that of the others. Additionally, it is evident that the magnitude of load transfer resistance (Rct), which indicates the value of metal resistance against metal ion was released which in the case of sample 3105 was about 15.6 times higher than that of 2024 alloy. In the Nyquist diagram, the diameter of each semicircular represents the corrosion resistance of each sample. According to this plot (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea), the semicircles' diameters were around 4000 Ω.cm\u0026sup2; in 2024 alloy, 11000 Ω.cm\u0026sup2; in 7075, 32000 Ω.cm\u0026sup2; in 5083, and 40000 Ω.cm\u0026sup2; in 3105 alloys. From these findings, it can be concluded that 3105 and 5083 alloys are more resistant to the dissolution of metal ions in the microbial environment, causing their resistance to corrosion in the same condition. As can be demonstrated, there is a respectable level of agreement between the results and the outcomes of the other tests, which shows that alloy 2024 has the highest and alloy 3105 has the lowest corrosion rates. According to the results of Fan et al., 2021, The Nyquist diagram's decreasing ring diameter during the incubation time indicates that \u003cem\u003eA. resinae\u003c/em\u003e is adhered to the sample surface and generates acidic metabolites [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. The number of loops (peaks) shows the number of time constants. High-frequency rings are created due to the capacity of the two electric layers formed between the oxide layer on the surface of the alloy and the solution, and these two electric layers are also called capacitive rings. Also, medium-frequency rings can be attributed to the loosening process of the oxide film. The results of the device are presented as point values ​​with a negative slope (Bode plot, Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb), and as can be seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec, there is only one peak that shows the dissolution of the oxide layer on the alloys.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003e3D Profilometeric Analysis\u003c/h2\u003e \u003cp\u003eAccording to the results obtained from previous tests, 2024 and 3105 alloys had the highest and lowest corrosion rates, respectively (See Supplementary Fig. S2 online for the obvious corrosion pits on the surface of the alloys). Based on these results, CLSM and 3D profilometry tests were performed on these two samples to compare the efficiency of corrosion on them. Using a 3D profilometer, the configuration of the pits on the coupon surface was assessed. The results indicated that the pits in the 2024 alloy are deeper than in 3105 where the maximum corrosion depth in the 2024 alloy was equal to 480 \u0026micro;m compared to 61 \u0026micro;m in 3105. The pits' structure, depth, and width were also analyzed through this method, showing that in contrast to alloy 2024, which had long, narrow corrosion pits, alloy 3105 had shallower, rounder, and wider corrosion pits. The dippest pit was observed after 50 days of incubation in alloy 2024. These outcomes prove the results of weight loss measurement and EIS analysis. The values ​​of the results are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, where the 3D figures and diagrams of the corroded areas of the surface of the samples are shown.\u003c/p\u003e \u003cp\u003eThe presence and percentage of some elements in the aluminum alloy component can be definitive to the severity of corrosion or in other words, the resistance of the metal to corrosion. For example, the amount of Mg in the 2024 alloy is less than 7075 and 5083 samples, and according to the investigation of Zhaohi et al. (2009), corrosion resistance increases with a higher amount of Al-Mg combination [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. Also, the present and changing value of Cu can lead to a different corrosion rate. 2024 alloy has the highest amount of Cu. The results obtained by Min-Sung Hong et al. (2017) show that the negative effect of pitting corrosion is increased by the presence of this element [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e] which is consistent with the results of this experiment.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003eCorrosion evaluation by CLSM\u003c/h2\u003e \u003cp\u003eThe CLSM technique was used to examine fungal biofilms, as well as how much biofilm was present in various areas of the surface after 50 days. In this test, the green color denotes the presence of fungal biofilm, and its intensity over the surface reveals how strongly the biofilm is adhered to the surface. Alloy 2024 had a more intense green color in its CLSM micrograph, while the irradiance was visibly lower in alloy 3105, indicating a thicker and more intense biofilm complex on the former alloy. These results are consistent with earlier research and indicate that alloy 2024 is more disposed to biofilm formation, which in turn increases the alloy's rate of corrosion.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusions","content":"\u003cp\u003ePrevious studies have shown that \u003cem\u003eA. resinae\u003c/em\u003e can affect the corrosion of aluminum alloys which is related to the ability of this fungus to produce a wide range of metabolites and organic acids under aerobic conditions. These corrosive metabolites can change the chemical nature of the environment and the electrochemical properties of the metal, leading to metal corrosion. The present study has focused on comparing the rate, severity, and depth of the mycocorrosion developed by \u003cem\u003eA. resinae\u003c/em\u003e on three aluminum alloys in 25-day intervals. Comparing the corrosion rate and resistance of the aluminum alloys, this experiment showed that alloys 2024 and 3105 had the highest and lowest corrosion rate, respectively. From the electrochemical analysis of impedance, it was found that the presence of fungus affected the metal's resistance to corrosion, and the resistance values of the samples in alloys 2024, 7075, 5083, and 3105 were respectively the lowest to the highest. These values were supported by outcomes of the microscopic observations in the CLSM analysis in which the intensity of biofilm formation on the 2024 alloy's surface was obviously higher than the most resistant alloy of the experiment (3105). The findings also confirmed that the intensity and depth of corrosion increases over time, as does the release of corrosion by-products, and the thickness and hardness of the biofilm. The observations and comparison results of this study can provide a better view to aluminum-using industries in order to accurately select the type of alloy depending on the corrosion resistance of each one.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEthics approval is not applicable as this article does not describe any studies involving human participants or animals.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data are included in the manuscript and additional information, and further queries about sharing data can be directed to the corresponding author.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eH.M. designed the project. A.H.S performed the experiments, A.H.S and M.G. wrote the paper, and M.E., M.G., and H.T. edited the manuscript. All the authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eDuret-Thual, C. Understanding corrosion: basic principles. \u003cem\u003eUnderstanding Biocorrosion: Fundamentals and Applications\u003c/em\u003e, 3-32 (2014). \u003c/li\u003e\n\u003cli\u003eJia, R., Unsal, T., Xu, D., Lekbach, Y. \u0026amp; Gu, T. Microbiologically influenced corrosion and current mitigation strategies: A state of the art review. \u003cem\u003eInternational biodeterioration \u0026amp; biodegradation\u003c/em\u003e \u003cstrong\u003e137\u003c/strong\u003e, 42-58 (2019). \u003c/li\u003e\n\u003cli\u003eVigneron, A., Head, I. M. \u0026amp; Tsesmetzis, N. 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Experimental study on the effects of three alloying elements on the mechanical, corrosion and microstructural properties of aluminum alloys. \u003cem\u003eResults in Materials\u003c/em\u003e \u003cstrong\u003e20\u003c/strong\u003e, 100485 (2023). \u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Aluminium alloys, Amorphotheca resinae, Corrosion, Mycocorrosion","lastPublishedDoi":"10.21203/rs.3.rs-4291481/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4291481/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e \u003cem\u003eAmorphotheca resinae\u003c/em\u003e 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\u0026times;105 Ω.cm\u0026sup2;) to corrosion, while the 2024 alloy was the most susceptible (7138 Ω.cm\u0026sup2;). 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 \u003cem\u003eA. resinae\u003c/em\u003e 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.\u003c/p\u003e","manuscriptTitle":"Evaluation of Mycocorrosion by Amorphotheca resinae in Aluminum Alloys 2024, 7075, 5083 and 3105: A Comprehensive Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-04-30 09:08:33","doi":"10.21203/rs.3.rs-4291481/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-06-26T05:02:11+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-12T18:57:34+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-05-30T01:54:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"216346172665014036567964115285860705215","date":"2024-05-20T02:49:47+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"285974488434738206630961012623526005586","date":"2024-05-19T15:14:04+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-05-19T11:50:09+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-05-19T11:48:30+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-04-29T10:59:13+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-04-25T08:23:04+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2024-04-19T07:14:12+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f3f451e7-538c-478a-a998-adbc012413ab","owner":[],"postedDate":"April 30th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":31310545,"name":"Biological sciences/Biological techniques"},{"id":31310546,"name":"Biological sciences/Biotechnology"},{"id":31310547,"name":"Biological sciences/Microbiology"}],"tags":[],"updatedAt":"2024-08-22T19:29:31+00:00","versionOfRecord":{"articleIdentity":"rs-4291481","link":"https://doi.org/10.1038/s41598-024-70150-x","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2024-08-17 15:57:21","publishedOnDateReadable":"August 17th, 2024"},"versionCreatedAt":"2024-04-30 09:08:33","video":"","vorDoi":"10.1038/s41598-024-70150-x","vorDoiUrl":"https://doi.org/10.1038/s41598-024-70150-x","workflowStages":[]},"version":"v1","identity":"rs-4291481","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4291481","identity":"rs-4291481","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}