Aqueous Sodium Chloride Solutions Research Articles

Enhanced electrical conductivity and stretchability of ionic-liquid PEDOT:PSS air-cathodes for aluminium-air batteries with long lifetime and high specific energy

A hydrogel film, poly-3,4-ethylenedioxythiophene (PEDOT):polystyrenesulfonate (PSS), containing an ionic liquid, is used as an air–cathode for a metal-air battery and its performance is investigated. This work presents the development of the air–cathode and the characterization of its physical, chemical and mechanical properties. Moreover, in view of wearable batteries, these air-cathodes are implemented within a flexible aluminium-air battery. It contains an aluminium anode, an electrolyte made of cellulose paper imbibed with an aqueous sodium chloride solution and the PEDOT:PSS air–cathode. Characterisation tests showed that the ionic liquid did not change the air–cathode chemically, while the electric conductivity increased considerably. The anode has an acceptable purity and was found to be resistant against self-corrosion. Discharge tests showed operating voltages up to 0.65 V, whereas two batteries in series could deliver up to 1.3 V at a current density of 0.9 mA cm−2 for almost a day, sufficient for monitoring and medical devices. Several discharge tests with current densities from 0.25 up to 2.5 mA cm−2 have presented operating lifetimes from 10 h up until over a day. At a current density of 2.8 mA cm−2, the operating voltage and lifetime dropped considerably, explained by approaching the limiting current density of about 3 mA cm−2, as evidenced by linear sweep voltammetry. The batteries showed high specific energies up to about 3140 Wh kg−1. Mechanical tests revealed a sufficient stretchability of the air–cathode, even after battery discharge, implying an acceptable degree of wearability. Together with the reusability of the air–cathode, the battery is a promising route towards a low-cost viable way for wearable power supply for monitoring medical devices with long lifetimes and high specific energies. Optimization of the air–cathode could even lead to higher power applications.

Behavior of the aqueous sodium chloride solutions from molecular simulations and theories

Molecular simulations and theories are important tools for studying electrolyte solutions. In this work, molecular dynamics simulations with one of the most widely used force field combination of water and alkali and halide monovalent ion parameters were first conducted for the aqueous sodium chloride solutions to predict density, self-diffusion coefficients and molar conductivity. Then the radial distribution functions were analyzed to obtain the first shell solvation radii and coordination numbers of ions, which were found practically unchanged against concentration. Together with the force field parameters, they were further applied into various molecular theories to predict the Gibbs energy of solvation, static relative permittivity, mean ionic activity coefficients and molar conductivity. It is remarkable to see that the mean ionic activity coefficients and molar conductivity can be predicted with deviations of 1.1 % and 1.4 %, respectively, up to 6 mol/kg H2O.

Unimpaired highly extensible tough chemically crosslinked hydrogel after experiencing freeze/thaw and boiling processes

AbstractA highly extensible, tough, chemically crosslinked double‐network (DN) hydrogel was synthesized from acrylamide. Three samples of this hydrogel were swelled using different solutions. One swelled in water, one in an aqueous glycerol solution, and one in an aqueous sodium chloride solution. The freezing points of the hydrogel samples were determined using differential scanning calorimetry (DSC). Then, the samples underwent controlled freeze–thaw cycles, and their mechanical behavior under loading‐unloading‐reloading large‐strain tensile deformation were analyzed. The results of these mechanical tests indicated that all the data points for deformation cycles coincided, despite the large water content of the samples. This means that no mechanical damage occurred during the deformation process. The results of hydrogel samples boiled in these solutions also showed no damage. Thus, it can be concluded that the tough chemically crosslinked DN hydrogel does not damage under large‐strain tensile deformations even after experiencing harsh environmental conditions, such as freeze/thaw or boiling processes, which makes it a great candidate for applications that involve large temperature variations. The resistance of the DN hydrogel to damage is attributed to the specific molecular architecture of this hydrogel, in that the building block of this material is a loosely crosslinked polymeric network.

Study on decolorization of methylene blue with a kind of electrolytic active water

Electrolytic active water was prepared by electrolytic treatment of sodium chloride aqueous solution using a self-made device. In order to investigate the properties of electrolytic active water , the pH value, available chlorine contents and decolorization ability on methylene blue solution were tested and compared with that of sodium hypochlorite aqueous solution. Experimental results showed that the electrolytic active water has higher oxidation capacity and decolorization efficiency for methylene blue compared with sodium hypochlorite solution, implying maybe other reactive oxygen species components besides hypochlorite existed in the electrolytic active water. The electrolytic active water was stable under long-term storage, and mechanical force with oxidation activity did not decrease. In addition, the decolorization kinetics of methylene blue in the electrolytic active water was explored, and it was found that, in general, the decolorization reaction of methylene blue in electrolytic active water was consistent with the first-order reaction kinetics model, but when the pH value of electrolytic active water solution was weakly alkaline or neutral, the decolorization reaction of methylene blue was closer to the second-order reaction kinetics model.

Voltage generation induced by thermo-driven ion solution flow in CNTs for low-grade thermal energy harvesting

The flow induced voltage generation has been regarded as an advanced energy harvesting technology at nanoscale with broad application prospects. The ionic liquid flow inside carbon nanotubes (CNTs) can be potential to harvest the low-grade thermal energy. In this work, the flow of aqueous solution of sodium chloride (NaCl) driven by the temperature gradient and the performance of voltage generation in CNT are investigated with the non-equilibrium molecular dynamics (MD) simulations. The accumulated displacement and the number density distribution of ions and water molecules are recorded in the simulations. The average flow velocities of ions are obtained and the flow-induced voltage is then predicted. The results show the thermal gradient along the axial direction of CNT drives the NaCl solution to flow from its hot end to cold one, which can drag the free charge carriers of CNT with a directional shift and generate a considerable voltage output. Moreover, the effects of temperature difference, CNT diameter and solution concentration on the ions flow and the flow-induced voltage are also studied. It is found the influence of the average flow velocity difference between Na+ and Cl− plays a dominant role on the flow-induced voltage, the different influencing factors show different rules in the variation of voltage generation. The findings in this work can contribute to the development of new energy-harvesting nano-devices for the low-grade thermal energy.

The effect of plasma flow on the properties of low-current arc in an open atmosphere

The electrical and optical properties of a low-current arc, which was blown by a plasma flow from a gas discharge with a liquid electrolyte cathode, were experimentally studied. The arc current varied in the range of 1-10 A. As a liquid electrolyte, aqueous solutions of sodium chloride with a specific electrical conductivity of 10-15 mS/cm were used. The arc and gas discharge with an electrolyte cathode were tied to a single-metal anode.

The Transfer Free Energetics of L-Cysteine in Aqueous Sodium Chloride Solutions

The Transfer Free Energetics of L-Cysteine in Aqueous Sodium Chloride Solutions

Effect of membrane mean pore diameter on water and solute flux in forward osmosis processes

Several forward osmosis (FO) experiments were carried out using aqueous solutions of sodium chloride (NaCl) in different concentrations, as draw solution (DS), and freshwater, as feed water (FW). The experiments were conducted at a constant temperature of ~20°C and using a symmetric cellulosic membrane in two grades different in their values of the molecular weight cut-off (MWCO), which is related to the mean pore diameter. This study investigates the effect of the membrane mean pore diameter on water flux and DS solute diffusional flux across the membrane. The value of water flux indicates the performance of the FO process, while solute flux is an important factor that determines its practicality. A proportionality factor is used to specify the relationship between water flux and solute flux for each membrane type and operational conditions. The results of this study show that water flux and solute flux increase as the solute concentration difference across the membrane increases. It is also found that, in the range of the tested membranes, membranes with larger mean pore diameters have lower water flux and higher solute flux.

The statistics of the Debye–Hückel limiting law

The Debye–Hückel Limiting Law (DHLL) correctly predicts the thermodynamic behavior of dilute electrolyte solutions. Most articles and books explain this law using Peter Debye and Erich Hückel’s original formalism of linearizing the Poisson–Boltzmann equation for a simple electrolyte model. Brilliant in its own right, this approach does not fully explain which microstates contribute in the range of the Debye–Hückel theory. Notably, the original formalism does not establish the Energy Multiplicity Distribution (EMD), which is the energy distribution of a system’s microstates. This work establishes an analytical expression for the EMD that satisfies the DHLL. Specifically, an EMD that is proportional to exp(aUel3) satisfies the DHLL for a monovalent electrolyte solution. Here, Uel is the effective electrostatic energy due to ion–ion interactions. The proposed proportionality shows quantitative agreement with the simulated EMDs of a Coulomb lattice gas that corresponds to an aqueous sodium chloride solution at a concentration of 3.559 × 10−4 M. The lattice gas that is used does not incorporate solvent molecules, but the Coulomb interactions are scaled through a permittivity that emulates the solvent—similar to the Debye–Hückel theory. Moreover, this work explains the proportionality by partitioning Uel into a set of energy contributions using minimal spanning graphs. This discussion on the EMD is new in the field. It widens the scope of the Debye–Hückel theory and could lead to a new parameterization option for developing equations of state.

A Study of the Lossy Mode Resonances during the Synthesis Process of Zinc Telluride Films.

Films of zinc telluride (ZnTe) were deposited on the surface of a chemically thinned section of an optical fiber by metalorganic chemical vapor deposition. The boundary values of temperatures and the concentration ratios of the initial tellurium and zinc precursors at which the synthesis of ZnTe coatings is possible are determined. The influence of the position of the thinned part of the optical fiber in the reactor on the growth rate of films on the side surface of the fiber was studied, on the basis of which, the parameters of the deposition zone were determined. By placing a section of an optical fiber with an etched cladding in the center of this zone, sensitive elements for refractometers were created. The principle of their operation is based on the dependence of the spectral position of the lossy mode resonance (LMR) maximum on the refractive index (RI) of the external medium. It has been found that even thin films deposited on a light guide in a continuous process have cracks. It is shown that the interruption of the deposition process makes it possible to avoid the appearance of defects in the zinc telluride layers even with the repeated deposition of the sensor. The sensitivity of the spectral position of the LMR to changes in the RI of aqueous sodium chloride solutions in the range from 1.33 to 1.35 for the first transverse electric and transverse magnetic LMRs was 6656 and 6240 nm per refractive index unit, respectively.

Analysis of florfenicol in pig plasma using a validated PPT-HPLC-DAD method

High performance liquid chromatography (HPLC) has proven to be an effective tool for examining the disposition kinetics of florfenicol (FF), a synthetic broad-spectrum antibiotic used to treat infectious diseases in veterinary medicine. Modification and optimisation of the protein precipitation (PPT) sample preparation procedure and HPLC with diode array detector (DAD) instrumental method were carried out to ensure conditions suitable for FF analyses in pig plasma samples. Stable supernatants with good plasma mean recoveries of FF (99.8% ± 0.7%RSD) were achieved using 1% v/v phosphoric acid solution in methanol and 10% w/v sodium chloride in aqueous solution. The PPT-HPLCDAD method’s detection limit of 0.004 μg/mL and quantification limit of 0.013 μg/mL provides high sensitivity for analyses of FF in plasma samples. In addition, the optimisation of method conditions resulted in shorter extraction and analysis time and less solvent consumption, which stresses the sustainability of this method in analytical chemistry. The optimised and validated PPT-HPLC-DAD method was applied in a comparative study of FF in pig plasma after administration of veterinary medicinal products. The study was conducted on fattening pigs following repeated intramuscular administration of two similar solutions for injection at a dose of 20 mg FF/kg bodyweight (test groups 1 and 2). The solutions for injection contained the same FF concentration, i.e., 300 mg/mL, but differed in excipients. The aim was to examine the influence of administrated solutions for injection on the extent of exposure to FF in pig plasma. The dynamics of kinetic profiles of FF in pig plasma from both treatments correspond to the FF kinetic profiles published in similar studies. However, differences were observed in the concentrations of FF, which were constant throughout the study, and statistical differences between the test groups were confirmed (P<0.05). Though these findings suggest the possible influence of excipients, a full comprehensive conclusion on the influence of administrated solutions for injection on FF exposure in pig plasma requires additional research.

Cerium Oxide on a Fluorinated Carbon-Based Electrode as a Promising Catalyst for Hypochlorite Production.

Sodium hypochlorite (NaOCl) is widely used as a disinfectant agent for water treatment and surface cleaning. A straightforward way to produce NaOCl is by the electrolysis of an aqueous sodium chloride (NaCl) solution. This process presents several side reactions decreasing its efficiency with hypochlorite reduction on the cathode surface being one of the main detrimental reactions. In this work, we have studied carbon-based electrodes modified with cerium oxide (CeO2), fluorine, and platinum nanoparticles as cathodes for hypochlorite production. Fluorination was carried out electrochemically; the polyol method was used to synthesize platinum nanoparticles; and the hydrothermal process was applied to form a CeO2 layer. Scanning electron microscopy, FTIR, and inductively coupled plasma (ICP) indicated the presence of cerium oxide as a film, fluorine groups on the substrate, and a load of 3.2 mg/cm2 of platinum nanoparticles and 2.7 mg/cm2 of CeO2. From electrochemical impedance spectroscopy, it was possible to demonstrate that incorporating platinum and fluorine decreases the charge transfer resistance by 16% and 28%, respectively. Linear sweep voltammetry showed a significant decrease in hypochlorite reduction when the substrate was doped with fluorine from −16.6 mA/cm2 at −0.6 V to −9.64 mA/cm2 that further reduced to −8.78 mA/cm2 with cerium oxide covered fluorinated electrodes. The performance of the cathode materials during hypochlorite production improved by 80% compared with pristine activated carbon cloth (ACC) electrodes. The improvement toward hindering NaOCl reduction is probably caused by the incorporation of a partial negative charge upon doping with fluorine.

Preparation of ethyl vanillin spherical particles with functions of sustained release and anti-caking by an organic solvent-free process

Ethyl vanillin is an important synthetic flavor that occupies a large market share in food additives. However, the shortcomings in terms of too fast aroma release rate and poor powder properties have severely limited its further application. In this work, the intrinsic mechanism of ethyl vanillin oiling-out process is revealed with the help of process analytical technologies. Further, a green and efficient spherical particles preparation technology is developed by constructing the oiling-out phase diagram of ethyl vanillin in the aqueous solution of sodium chloride. The ethyl vanillin spherical product has excellent powder properties with high bulk density (0.74 g/cm3), good sphericity (93.4 %), high flowability (29°), high yield (>95 %) and adjustable particle size distribution. More importantly, the spherical product exhibits 57.9 % lower aroma release rate at 323.15 K and 1400 % higher critical caking cycle compared to irregularly shaped powder, which confirms its sustained release and anti-caking function.

Influence of aqueous sodium chloride solutions on operational properties of epoxy coatings

The main goal of the research presented in the article is to assess the impact of the destruction (degradation) of epoxy coatings, caused by the influence of a 25% aqueous solution of sodium chloride (brine), on the operational properties that determine the coatings reliability (durability). Samples of two-layer epoxy coatings (obtained from powder paints) were aged by immersing them in brine for a maximum period of 1680 h. The following criteria were used to assess the operational properties of the coatings: thickness, roughness and surface morphology, hardness, water absorption (mass increase), surface free energy. The FTIR and DSC tests performed showed a progressive development of the oxidation processes of the epoxy with the ageing period. The long-term impact of the brine resulted in the destruction of the coatings in the form of: craters, grooves, microcracks, including silver cracks. The contact of the coatings with brine also increased their: surface roughness (Ra, Rz, Rmax), thickness, mass, surface free energy, and decreased hardness and heat resistance.

ОСОБЛИВОСТІ ФОРМУВАННЯ ПОВЕРХНЕВИХ ШАРІВ НА МЕТАЛАХ

The practical application of metal alloys, in particular amorphous ones, often necessitates the creation of multifunctional coatings of various nature and purpose on their surfaces. The main requirements for obtaining optimal results of applying such coatings are as follows: 1. Understanding of the morphology of the surface before coating. 2. Information on the physical and mechanical properties of the metal-coating composition. 3. Testing of the adhesion strength immediately after coating. 4. The use of different methods of control of the application and functionality of the coating, depending on the operating conditions of the product. The reliability of functional coatings also depends on the preparation of the surface of the material, as well as the choice of appropriate conditions for its formation. However, regardless of the purpose, a general requirement that all coatings must meet is a good adhesion to the surface of the substrate material. It is also important to ensure the uniform thickness in different areas (protrusions and depressions), because the thickness of the coating determines the longevity of its protective effect. Also, the coatings should have very low rate of dissolution even in the most aggressive environments in which they work. Therefore, the problem of creating optimal coatings is complex and requires a comprehensive study in each specific case. In the case of industrial use of amorphous metal alloys (AMA) based on transition metals with different alloying elements, special attention must be paid to the elemental composition of the surface of the finished products, which can differ significantly from the quantitative composition of the initial charge, which depends on the nature of the components and the applied protocol of ultra-fast cooling of the melt. The difference in the elemental composition on the surface and in the volume of the amorphous alloy is also due to the possible formation of surface chemical compound i.e. metal oxides. The protective properties are evaluated by the speed of metal oxidation, the formation of a layer and the duration of its action. Comparative assessment of the reactivity of amorphous alloys Al87.0Y5.0Ni8.0, Fe73.6Cu1.0Nb2.4Si15.8B1.2, Fe78.5Ni1.0Mo0.5Si6.0B14.0, Co75.5Fe4.6Si6,B16.7 in an aqueous solution of sodium chloride was carried out using electrochemical studies. The main requirements for obtaining optimal results of applying protective coatings on crystalline and amorphous surfaces have been analyzed.

Effect of exopolymer gels on the viscoelasticity of mucus-rich saltwater and settling dynamics of particles

Algal blooms enrich seawater with gel-like exopolymers modifying the local structure and physio-chemical properties of water column. These effects are particularly intense during mucilage events occurring seasonally in some seas and coastal regions and in thin layers. However, detailed in situ examination is limited, and the effects of biologically modified seawater on microscale processes remain poorly understood. In this study, we experimentally investigated the impact of exopolymer gels on rheological properties of mucus-rich saltwater and consequences on settling dynamics of fast-sinking particles using aqueous solutions of sodium chloride with an addition of xanthan gum, a model exopolymer forming gels dispersed in water. We studied two types of solutions: colloidal dispersion and dispersion with predominant content of particulate gels. The results showed that dispersions consisting of colloidal exopolymers have stronger inner structure than dispersions with predominant particulate exopolymers, suggesting that viscoelastic properties of seawater vary with the structure of gels. Settling velocity and drag exerted on solid spheres and disks were substantially different for the two types of solutions, with the drag coefficient up to six times higher for colloidal than for particulate solutions of corresponding salinity, indicating that colloidal exopolymers may retard particles falling in marine environment more effectively than particulate gels. The findings highlight possible variation in viscoelasticity of mucus-rich saltwater with exopolymer network structure changes in spatial and temporal scales during algal bloom development and implications to the sedimentation of fast-sinking particles such as faecal pellets, carbonate grains, minerals and microplastics.

Stress corrosion cracking of AISI 304 under chromium variation within the standard limits: Failure analysis implementing microcapillary method

This study focuses on the failure analysis of an industrial part made of AISI 304 that severely ruptured, while another identical part operated under identical service conditions has no sign of fracture. Various electrochemical polarization responses and stress corrosion cracking (SCC) susceptibility were compared by employing the microcapillary method on representative samples. The dominant factor was identified to be the chromium (Cr) content variation within the range of standard designations. Various concentration levels of sodium chloride aqueous solution were studied for both strained and unstrained conditions. Results highlighted higher susceptibility to pitting and SCC for the specimens with lower Cr content, indicating a more severe condition at higher chloride concentrations.

Stably electrospraying highly conductive sodium chloride aqueous solution coated with outer ionic liquid using coaxial capillary

Concentrated aqueous solutions with high conductivity have been proven difficult to be stably electrosprayed mainly due to their large surface tension, which will easily trigger air discharge. The ionic liquid with lower surface tension is involatile, viscous, and highly conductive and can easily achieve stable electrospray. This paper presents a more convenient method to ionize the concentrated aqueous solution than the previous attempts and proves the feasibility of coaxially electrospraying two highly conductive liquids (∼1 S/m). Our method utilizes a coaxial capillary to coat the highly conducting concentrated sodium chloride (NaCl) aqueous solution (0.67 S/m) with a thin layer of immiscible ionic liquid to form a compound cone and achieve the stable coaxial electrospray. The compound cone remains static at a suitable flow rate (0.1–1 nl/s) of the ionic liquid. At a higher or lower flow rate, the compound cone elongates or shrinks and eventually vibrates. Due to the high conductivity of both liquids, the spray current does not follow the current scaling law. The spray current is mostly dominated by the NaCl solution and counterintuitively decreases as the flow rate of the ionic liquid increases due to the frequent vibration of the compound cone. The highly conducting thin layer of the ionic liquid is the key to achieving stable coaxial electrospray. It lowers the surface tension of the compound cone and shields the external electric field acting at the inner aqueous solution; thus, the air discharge of the aqueous solution is suppressed, and the stable compound cone can be formed.

Neutron scattering on an aqueous sodium chloride solution in the gigapascal pressure range

An aqueous 3 m (=mol kg−1) NaCl solution in D2O is investigated at 0.1 MPa (hereafter denoted as 0 GPa)/298 K, 1 GPa/298 K, 1 GPa/523 K, and 4 GPa/523 K by neutron scattering combined with an empirical potential structure refinement (EPSR) method. The pressure and temperature dependence of the ion solvation and association and solvent water structure is discussed in pair correlation functions, coordination number distributions, angular distributions (orientational correlation), and spatial density functions (3D structure). The Na+ solvation is characterized as nearly octahedral coordination with about five water molecules and one Cl− over a pressure range measured. The Na–Ow (water oxygen) and Na–Dw (water hydrogen) distances are 2.34–2.37 Å and 2.82–3.00 Å, respectively. The water dipole is tilted by about 31° from the Na–O bond direction and the angle distribution becomes broader with an increase in pressure and temperature. The Cl− solvation shows a change in the coordination number of a water oxygen atom from 11 at 0 GPa to 15 at 4 GPa. An increase in the coordination number of a water hydrogen atom with pressure is observed; the values fall within five to six. The first neighbor Cl–Dw and Cl–Ow distances are 2.19–2.28 Å and 3.10–3.21 Å, respectively. The hydrogen-bonded angle Cl−···Dw–Ow is almost linear over a whole pressure range, but the angle distribution becomes broader upon compression. Another interesting finding of the Cl− solvation is the formation of extended solvation shells of Cl− in the gigapascal pressure range as if they behave as a structure making ion as Na+. The extended solvation shell of Cl– is caused by the breakdown or distortion of the hydrogen-bonded network of solvent water under compression. The coordination number of water oxygen increases from 4.7 at 0 GPa to 12–13, close to a value seen in simple liquids like Ar at 1–4 GPa. Despite such a drastic increase in water oxygen coordination number, the coordination number of the water hydrogen decreases from 2.2 at 0 GPa to 1.8 at 4 GPa, with the Ow–Dw distance lengthening from 1.77 Å to 1.95 Å, i.e., the hydrogen bonds between water molecules are retained in the gigapascal pressure range. The hydrogen bond angle Ow···Dw–Ow is almost linear, but the angle distribution is broadened upon compression, suggesting the distortion of the hydrogen bonds. Thus, it is concluded that compression of an aqueous NaCl solution to the gigapascal pressure causes the distortion of the hydrogen bonds between water molecules, resulting in the formation of the second and extended shells of a structure breaking Cl−.

Fatigue Life Estimation of 7020 Aluminum Alloy Subjected to Aqueous Sodium Chloride Solution

The 7020-aluminum alloy is a lightweight and high strength material which is widely used in aerospace industries where the damage tolerance, the factor of safety and environmental induced fatigue is very high. The low density and better mechanical properties enable its applications in industries over conventional engineering materials. In the present work, the fatigue crack growth (FCG) behavior of the pre-corroded 7020-aluminum alloy was investigated. The samples were subjected to an aqueous solution of sodium chloride; the micro-hardness was optimized and the significance of corrosion on FCG was studied in the context of bending stress, the number of cycles (N) to failure/fatigue life and microstructure. The solution treated samples at a temperature of 520°C for 3 hours provided the maximum hardness. However, the hardness of samples was optimum for 3 hours of solution heat treatment and minimum for 2 hours of solution heat treatment. It is suggested that the precipitation of the metastable phase affected the hardness. In the initial stage, the fatigue life of pre-corroded samples was significantly lower as compared to as-received samples. However, at the later stage, it became less significant but still, the pre-corroded sample showed lower fatigue life. Both types (pre-corroded and as-received) of samples showed a similar trend as fatigue life decreases with increasing bending stress. The fractured microstructure of the pre-corroded sample showed scratches on the surface which were produced during mechanical rubbing of the specimen pieces during plastic deformation under load. However, the microstructure at the edge of the notch showed "volcano-mouth" features" which indicated the phenomena of galvanic corrosion. The galvanic corrosion envisages due to deposition on the 7020-aluminum alloy and the impurities in the alloy. The elements Fe, Si, C and Mn existed as impurities that induced the galvanic corrosion and an elliptical corrosion pit was observed.