Impedance Spectroscopy Methods Research Articles

Synergistic corrosion inhibition of rubber seed extract with KI on cold rolled steel in sulfuric acid solution

BackgroundPlant-based inhibitor has emerged an important topic owing to the combing merits of eco-friendly, low cost, rich natural resources as well as easy preparation. Rubber seed is the agricultural waste, and is mainly composed of oil and fatty acids those contain many polar oxygen atoms, and so it can be extracted to prepare the potential corrosion inhibitor. MethodsRubber seed extract (RSE) is prepared using reflux extraction method with the extracting solvent of ethanol aqueous solution. The synergistic inhibition effect of RSE and potassium iodide (KI) on the corrosion of cold rolled steel (CRS) in 0.50 M H2SO4 solution is firstly studied by weight loss, potentiodynamic polarization (PDP) curves and electrochemical impedance spectroscopy (EIS) methods. CRS surface was thoroughly characterized using metallographic microscope, scanning electron microscope (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS) and contact angle measurements. FTIR, UV–vis and liquid chromatography mass spectrometry (LC-MS) compositional analysis of RSE were used to analyze the efficient components in RSE. Significant findingsThe results indicate that individual RSE or KI cannot function as a successful inhibitor to prevent CRS corrosion, but the mixture of RSE/KI performs better at inhibiting, with a maximal inhibition efficacy of up to 96.4% of 200 mg L−1 RSE/100 mg L−1 KI. The synergistic coefficient of the mixture is larger than 1, indicating that a true synergism. RSE/KI can drastically retard both cathodic and anodic processes, and interfacial capacitance falls as the charge transfer resistance of CRS/solution rises. It exhibits remarkable inhibition properties when the capacitor arc grows. There is only a small corrosion response in the inhibited media, as evidenced by the variations in electrical conductivity and ultraviolet spectrum before and after immersion. The hydrophilicity and surface roughness of CRS surface is dropped as a result of the introduction of RSE/KI. A series of metallurgical microscopy, AFM, SEM or contact angle tests indicate a synergistic inhibition effect is more pronounced for RSE/KI. XPS results clearly demonstrate that elements including Fe, S, N, and I are bonded to the surface of CRS. The primary ingredients of oleic acid, polyphenols, phenylpropanoids can also produce a strong synergism with KI.

Impedance-Based Method for Predictive Stability Assessment

Impedance-based analysis methods enable a more specific and earlier foundation for assessing harmonic stability in decentralized converter-based power plants compared to the conventional compliance testing in the grid connection process. Essentially, they can be implemented as black-box model approaches without the necessity to disclose internal control models. Initially, only knowledge of the input impedances of the planned grid connection point and the planned PV system is required for application. For this purpose, the method of impedance spectroscopy for inverters has already been developed as a means to determine the effective impedance profile and the internal harmonic sources of inverters, allowing for the description of the frequency-dependent behavior of individual units. The time- and frequency-dependent grid impedance at the grid connection point (GCP) has also been successfully measured in several campaigns on medium and low-voltage grids. Through the coordinated application of both measurement methods, a predictive harmonic assessment is intended in the future, ensuring high planning reliability and grid quality even in grids with a high penetration of power electronics-coupled systems. This paper provides an overview of the current state of research on impedance-based stability criteria and presents measurement methods for practical implementation. Furthermore, it outlines remaining open questions until application in the field.

Evaluation of adults' acumen exerted from cerebral stress with quantified anthropometric indices using bioelectrical impedance analysis

This work considers cerebral stress-struck adults to assess their ‘acumen’ with four quantified anthropometric indices like cell membrane capacitance (CM), total body impedance (TBI), total body fat (TBF), and total body water (TBW). Primarily, a bio-impedance model of the epithelial tissue structure of human body has been presented and anatomized considering mental stress driven hormonal changes happen inside human body to propose several preambles. Secondly, an intelligence quotient (IQ) test designed to create ‘racing’ thoughts has been conducted right before measuring indices using bioelectrical impedance spectroscopy (BIS) method. Finally, juxtaposed investigations to vindicate the correlation between bio-impedance model-implied preambles and the variance of the four quantified indices were made by comparing them to the IQ test outcomes. This article reports, an effectively innervated nervous system having homeostasis endocrine human anatomy with CM, TBI, TBF, and TBW, in the range of 1.0–2.1 nF, 470–550 Ω, 7.9–20%, and 56.8–80%, respectively for the subjects whose acumen is classified as “Class-A", while “Class-B" subjects are also presented with other distinct quantified indices. The outcomes of this work are expected to be a paradigm in the digital judgment of adults' psychological engagement to any tasks.

Exploring Impact of Various Operating Parameters on the Specific Capacitance at the Glassy Carbon/H2SO4 Interface: A Comparative Analysis Using Electrochemical Characterization

AbstractThe aim of this study is to investigate the influence of scanning rate, electrolyte concentration, temperature and electrode rotation speed on the capacitance of glassy carbon electrode in sulfuric acid solution using cyclic voltammetry (CV). The results show that they have a significant influence on the capacitance with varying experimental conditions. In addition, the electrochemical impedance spectroscopy (EIS) method was employed to conduct a more thorough analysis of the ways in which hydrodynamic circumstances resulting from a rotating electrode affect the electrode capacity and the charge storage process. Step potential electrochemical spectroscopy (SPECS) was used to identify the various charge storage mechanisms involved. It was shown that the voltammograms measured by the CV method and determined from the SPECS method have a quasi‐rectangular shape, revealing a predominantly capacitive behavior and that capacitance decreases with increasing scanning rate. Furthermore, both methods confirm that the contribution of the diffusion process is the main factor influencing the charge storage mechanism when the sweep rate is taken into account. However, the SPECS approach provides more accurate and detailed information regarding the kinetic characteristics of the electrode.

A novel method for improving the electrochemical properties by modifying conductive polymer on 3D printed nanocarbon electrode

The technology of 3D printing has emerged as a potent tool for the preparation of 3D-printed electrode. Using commercial graphene/polylactic acid (PLA) composite filaments as printed materials, fused deposition modeling as 3D-printed technique, 3D printed electrodes (3DEs) were created in this work. Gold nanoparticles (AuNPs) and the composites of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) were used to modify the activated 3DEs for constructing a novel electrode(SACP@Au@3DE), and in this work chlorogenic acid (CGA) was regarded as a probe for testing the performance of SACP@Au@3DE. The surface physicochemical properties of the prepared 3DEs were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The electrochemical properties of the prepared 3DEs were investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods. The constructed SACP@Au@3DE can be used to determine CGA at concentrations ranging from 10 to 400 μM with a limit of detection (LOD) of 4.13 μM. Ultimately, the SACP@Au@3DE sensor was used for CGA detection in coffee powder sample to explore the potential for real sample analysis. This work opens the novel avenue of using conductive polymer modified 3D-printed electrode in the field of sensor.

Comprehensive assessment of thermoelectric properties in modules: Time-domain impedance spectroscopy considering heat leakage via attached lead wires

This study aimed to determine various thermoelectric properties, including the dimensionless figure of merit (zT0), resistivity (ρTE), thermal conductivity (κTE), and Seebeck coefficient (S), using a combination of 3ω and time-domain impedance spectroscopy (TDIS) methods for a thermoelectric module at absolute temperature (T0). The effective dimensionless figure of merit (zT0,eff), influenced by heat leakage through attached lead wires, was quantitatively and qualitatively assessed based on the TDIS method. The results demonstrated that zT0,eff/zT0 can be expressed as the ratio between the thermal conductance of the attached thermoelectric element and the lead wire. Thus, by considering heat leakage through the lead wire, the TDIS method can estimate not only zT0 and ρTE but also κTE and S after measuring the lead wire's thermal conductivity using the 3ω method. The study utilized a commercial Π-shaped bismuth-telluride-based thermoelectric module and derived representative values for its elements. zT0, ρTE, κTE, and |S| at 300 K were 0.871, 10.15 μΩ m, 1.71 W/mK, and 224 μV/K, respectively, consistent with previous reports on representative bismuth-telluride-based materials. In conclusion, the combination of the 3ω and TDIS methods is useful for determining all thermoelectric properties, considering heat leakage through attached lead wires.

Preparation and opto-electrical characterization of poly(ethylene oxide) based polymer blends for electrochemical applications

Solid polymer electrolyte blends with varied compositions of poly(ethylene oxide) (PEO)/carboxymethyl cellulose (Na-CMC) in 10/90, 50/50, and 90/10 compositions have been successfully prepared by means of the solution cast technique at room temperature. The modification of the structural, optical, and electrical properties of the prepared blend samples was studied by employing XRD, FTIR, UV-Vis, and electrical impedance spectroscopy methods. X-ray diffraction studies revealed that the crystalline nature gradually transforms into amorphous as the Na-CMC content increases in the sample. The variation of bands noticed in the Fourier transform infrared spectroscope characteristic spectrum of the blends reveals the formation of complexes between the individual polymers. The analysis of optical properties using a UV-Vis spectrometer in the wavelength range of 900–1100nm, shows a gradual decrease in the optical indirect energy band gap with an increase in Na-CMC content in the blend. The study of the electrical properties of the blend carried out in the frequency range 50 Hz–1MHz and temperature range 303K–338K, using an electrical impedance analyzer reveals that, the dielectric constant and loss decrease with the rise in frequency, exhibiting the usual behavior of the polymers. AC conductivity is found to increase with an increase in temperature. The highest value of ionic conductivity is found to be 6.06 × 10−3Scm−1 for the blend with a 10/90 composition.

Densification and corrosion properties of graphite reinforced binderless TiC70N30 ceramic composites

In this study, binderless TiC70N30 ceramic composites with varying graphite (TiC70N30–Gr) reinforcements were fabricated via spark plasma sintering and their effect on densification was assessed. Subsequently, the electrochemical behaviour of TiC70N30–Gr composites was evaluated in 0.5 mol/L hydrochloric acid (HCl), 0.5 mol/L sulphuric acid (H2SO4) and 0.5 mol/L nitric acid (HNO3) solutions using open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. The corrosion behaviour of TiC70N30-based ceramic composites with and without graphite reinforcement exhibited high corrosion resistance in the acidic electrolytes. Composites with 0.5 and 1.0 wt% graphite content showed lower Icorr values of 0.452 µA and 0.081 µA in 0.5 mol/L HCL and 0.5 mol/L HNO3, respectively, while specimen without graphite addition showed better corrosion resistance in 0.5 mol/L H2SO4 (0.041 µA). Based on the corrosion results, the corrosion properties of TiC70N30 ceramic composites in HCl and HNO3 solutions were significantly enhanced upon the incorporation of graphite reinforcements. However, the corrosion test results conducted in H2SO4 solution showed that the addition of graphite had a negligible influence on the corrosion resistance of the titanium carbonitride (TiCN) composites.

Exploring the Impact of Copper Oxide Substitution on Structure, Morphology, Bioactivity, and Electrical Properties of 45S5 Bioglass®.

In recent decades, the requirements for implantable medical devices have increased, but the risks of implant rejection still exist. These issues are primarily associated with poor osseointegration, leading to biofilm formation on the implant surface. This study focuses on addressing these issues by developing a biomaterial for implant coatings. 45S5 bioglass® has been widely used in tissue engineering due to its ability to form a hydroxyapatite layer, ensuring a strong bond between the hard tissue and the bioglass. In this context, 45S5 bioglasses®, modified by the incorporation of different amounts of copper oxide, from 0 to 8 mol%, were synthesized by the melt-quenching technique. The incorporation of Cu ions did not show a significant change in the glass structure. Since the bioglass exhibited the capacity for being polarized, thereby promoting the osseointegration effectiveness, the electrical properties of the prepared samples were studied using the impedance spectroscopy method, in the frequency range of 102-106 Hz and temperature range of 200-400 K. The effects of CuO on charge transport mobility were investigated. Additionally, the bioactivity of the modified bioglasses was evaluated through immersion tests in simulated body fluid. The results revealed the initiation of a Ca-P-rich layer formation on the surface within 24 h, indicating the potential of the bioglasses to enhance the bone regeneration process.

Successful synthesis of proton-conducting high-entropy (La0.2Nd0.2Ho0.2Lu0.2Y0.2)2ZrO5 ceramics

Using mechanical activation of an oxide mixture containing 0.2 wt% hexagonal boron nitride, followed by high-temperature firing (1400–1500 °C), we prepared single-phase (La0.2Nd0.2Ho0.2Lu0.2Y0.2)2ZrO5 ceramic, a high-entropy oxide (HEO) analog of Gd2ZrO5, whereas we failed to obtain single-phase Gd2ZrO5 under similar conditions: the material consisted of two phases, with the fluorite and bixbyite structures, like in the case of conventional synthesis or coprecipitation in previous work. Thus, the use of the HEOs allowed us to obtain a phase-pure compound with the fluorite structure at a markedly lower synthesis temperature. An important role was played by 0.2 wt% hyperstoichiometric hexagonal BN additions, which ensured considerable amorphization of the starting oxides. The start powders and resulting ceramics were studied by X-ray diffraction, SEM analyses and conductivity was measured by impedance spectroscopy method in dry and wet air.The highest proton conductivity, ∼2.5 × 10−5 S/cm at 630 °C, was offered by the (La0.2Nd0.2Ho0.2Lu0.2Y0.2)2ZrO5 HEO ceramic. The use of HEO analogs of various compounds can be helpful for not only assessing thermodynamic properties of ceramics (reduction in synthesis and polymorphic transformation temperatures), but also preparing proton conductors when it is necessary to enhance hydrating properties of the cation sublattice.

Investigation of the Electrochemical Corrosion Property of 2xxx Series Cast Aluminium Alloy in 0.3 M, 0.6 M NaCl, and Seawater Environments

The electrochemical corrosion activities of 2xxx series Al alloys were investigated in NaCl of 0.3 M, and 0.6 M concentrations and seawater environments. Both Tafel polarization and electrochemical impedance spectroscopy (EIS) methods were followed to analyze the corrosion behavior. These results implied that corrosive attack is more aggressive in sodium chloride solution compared to seawater, as additional elements present in seawater are involved in forming various protective layers. Again, a higher concentration of NaCl solution damaged the alloy surface more drastically. The open circuit potential moved towards the nobler direction in the case of seawater environment, and 0.3 M solution for NaCl. The corrosion rate and corrosion current showed higher values in NaCl solution than in seawater. The surface morphologies of the alloys were characterized not only with an optical microscope but with a scanning electron microscope also. The scratch marks from polishing were removed after corrosion. Extensive damage to the surface was found in the NaCl environment, where 0.6 M solution created the most damage, which is evident by both optical and scanning electron micrography. A higher level of pitting corrosion occurred in NaCl than in seawater, identified by SEM images.

Data-driven internal temperature estimation methods for sodium-ion battery using electrochemical impedance spectroscopy

As sodium-ion batteries (SIBs) move towards commercialization, safety monitoring of SIBs has become the next key issue, and how to avoid thermal runaway is one of the toughest challenges. The electrochemical impedance spectroscopy (EIS) method for the internal temperature estimation of lithium-ion batteries has received considerable attention due to its non-invasive detection and high accuracy. However, research on the impedance-temperature characteristics of commercial SIBs remains limited, and EIS methods suitable for estimating the internal temperature of SIBs require further investigation. In this study, four commercial 26,700 SIBs were tested, the EIS results of the batteries in various state-of-charge (SoC) states and at different temperatures were systematically investigated, and a method for estimating the internal temperature of SIBs on the basis of the combination of EIS and machine learning (ML) is proposed. Seven component parameters were extracted as features from the raw EIS data using equivalent circuit model fitting, and four features, which were found to be highly correlated with temperature, were further selected by correlation analysis. The mapping relationship between the extracted features and the internal temperature of the battery was established based on three ML regression models. Results demonstrate that the average estimation error of the multi-layer perceptron models for the internal temperature of the battery with unknown SoC states is only 1.086 °C. This paper fills the gap in the temperature characterization of EIS for SIBs and proposes an effective method for overcoming the cross-coupling of the battery EIS with the SoC and temperature within the framework of mechanical learning to estimate the internal temperature of SIBs.

CPE-Na-Based Hole Transport Layers for Improving the Stability in Nonfullerene Organic Solar Cells: A Comprehensive Study.

Organic photovoltaic (OPV) cells have experienced significant development in the last decades after the introduction of nonfullerene acceptor molecules with top power conversion efficiencies reported over 19% and considerable versatility, for example, with application in transparent/semitransparent and flexible photovoltaics. Yet, the optimization of the operational stability continues to be a challenge. This study presents a comprehensive investigation of the use of a conjugated polyelectrolyte polymer (CPE-Na) as a hole layer (HTL) to improve the performance and longevity of OPV cells. Two different fabrication approaches were adopted: integrating CPE-Na with PEDOT:PSS to create a composite HTL and using CPE-Na as a stand-alone bilayer deposited beneath PEDOT:PSS on the ITO substrate. These configurations were compared against a reference device employing PEDOT:PSS alone, as the HTL increased efficiency and fill factor. The instruments with CPE-Na also demonstrated increased stability in the dark and under simulated operational conditions. Device-based PEDOT:PSS as an HTL reached T80 after 2500 h while involving CPE-Na in the device kept at T90 in the same period, evidenced by a reduced degradation rate. Furthermore, the impedance spectroscopy and photoinduced transient methods suggest optimized charge transfer and reduced charge carrier recombination. These findings collectively highlight the potential of CPE-Na as a HTL optimizer material for nonfluorine OPV cells.

CORROSION EVALUATION OF LPBF-MANUFACTURED DUPLEX STAINLESS STEEL

In this study, the effect of as built and heat-treated additively manufactured 2507 super duplex stainless steel (SDSS) on electrochemical corrosion performance was examined. The corrosion was studied by Tafel polarization and electrochemical impedance spectroscopy (EIS) methods in a 3.5% NaCl solution. For this purpose, the as-built and heat-treated printed samples (solution annealed and stress-relieved) were examined by LOM/SEM and X-ray diffraction to evaluate the phase changes of steel at different processing stages. The correlation between corrosion resistance, structure, and heat treatment was assessed. As a result of the very fast cooling rate of the LPBF process, SDSS reveals ferrite as the major phase in the printed samples. To enhance the corrosion resistance of LPBF-produced duplex stainless steel, it's crucial to balance its two-phase structure and minimize residual stresses. The ferrite grains are elongated in the build direction, with some austenite precipitation along the grain boundaries or as Widmanstatten laths. The stress-relieved and as-printed SDSS exhibits reduced corrosion characteristics by around 20% compared to the solution-annealed SDSS, according to anodic polarization curves. Based on EIS results, the solution-annealed SDSS revealed an almost double increase in corrosion resistance (based on charge transfer resistance values) compared to the as-printed and stress-relieved conditions.

Silver Nanoparticles Decorated in In Situ Reduced Graphene Oxide Nanohybrids Improved Properties in Poly(vinylidene fluoride)/Poly(methyl methacrylate) Blends

In this paper, reduced graphene oxide decorated with silver nanoparticle (rGO-Ag) nanohybrids were prepared using an environmentally friendly approach and incorporated as reinforcement in poly(vinylidene fluoride)-poly(methyl methacrylate) blends via a melt mixing process. The microstructure of rGO-Ag nanohybrids and its effect on the microstructure, mechanical, thermal, and electrical properties of the PVDF/PMM/rGO-Ag was studied using Fourier transform infrared (FTIR), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), tensile, thermogravimetric analysis (TGA), and impedance spectroscopy methods. FTIR and TEM analysis confirmed that rGO-Ag successfully synthesized and Ag nanoparticles are located on the rGO surface. The tensile analysis demonstrated that incorporating 1 wt.% of rGO-Ag in PVDF/PMMA blend increases Young’s modulus and strength of nanocomposite up to 31% and 35%, respectively. The Halpin-Tsai model was also used for PVDF/PMMA/rGO-Ag nanocomposites, and the results confirmed that this model works well to predict the tensile modulus. Impedance spectroscopy analysis showed that the presence of rGO-Ag nanohybrids in PVDF/PMMA blend effectively enhanced the conductivity of PVDF/PMMA blend. TGA results demonstrated that the presence of rGO-Ag nanohybrids enhanced the thermal stability of nanocomposites and increased the degradation temperature of PVDF/PMMA/rGO-Ag nanocomposites in the range of 20°C compared to PVDF/PMMA blend.

Investigation on chloride migration behavior of metakaolin-quartz-limestone blended cementitious materials with electrochemical impedance spectroscopy method

Calcined clay and limestone powder composites offer a viable solution for reducing carbon emissions in building materials by allowing significant cement replacement. However, there is a need for further investigation into their impact on durability, especially for low-grade clays. In this study, different ratios of metakaolin and quartz powder are utilized to simulate various grades of calcined clay, while limestone powder is incorporated as a partial cement substitute. Initially, the influence of metakaolin content on rapid chloride migration was analyzed. Subsequently, various analytical techniques such as free water content, Mercury Intrusion Porosimetry (MIP), X-ray diffraction (XRD)/Rietveld method, and electrochemical impedance spectroscopy (EIS) test were employed to investigate the effects of metakaolin contents on the pore structure, phase assemblage, and electrochemical parameters of the blended cementitious system. The relationship between chloride migration coefficient and free water content, critical pore size, and impedance parameters was established to determine the key indicators for chloride migration. The study revealed that systems with partial metakaolin content demonstrate improved chloride resistance in the blended system, which could be predicted using Rct1 from the EIS test. Furthermore, the inclusion of metakaolin and limestone powder facilitated the formation of Monocarboaluminate (Mc) and Hemicarboaluminate (Hc), leading to the refinement of the pore structure and inhibition of chloride transport within the blended material. This study indicates the potential of low-grade calcined clay to enhance the overall durability of the blended cementitious system while contributing to carbon emissions reduction.

The Inhibition Action of Some Brij-Type Nonionic Surfactants on the Corrosion of OLC 45 in Various Aggressive Environments.

The corrosion protection property of three Brij-type surfactants, namely, Brij 35, Brij 56 and Brij 58P, was considered on OLC 45 carbon steel in a 0.5 M H2SO4 medium. The efficacy for these organic compounds was examined using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods, scanning electron microscopy (SEM) procedures, and Fourier transform infrared (FT-IR) spectroscopy. We hypothesized that these surfactants hinder the corrosion for OLC 45 samples through a protecting mechanism owing to the adsorption of organic molecules that form an inhibitive film or through the formation of complex oxides. These surfactants exhibited an appreciable protective effect against OLC 45 corrosion, operating as mixed inhibitors, as could be demonstrated by their influence on the electrochemical characteristics of the metallic substrates. The adsorption of surfactants over the substrates zone conformed to the representation of the Langmuir isotherm. The effect of temperature on the electrochemical comportment of the OLC 45 specimens in H2SO4 without and with Brij at 800 ppm was examined in the temperature interval of 293 to 333 K. The negative estimate of thermodynamic attributed as Gibbs free energy of adsorption presented the spontaneity of the adsorption activity. The investigation with FT-IR and SEM established the adsorption of Brij and the constitution of the corrosive components on the OLC 45 surface. Electrochemical determinations of these surfactants indicated its anticorrosion inhibition performance and the highest inhibition of 96% was reached when the Brij 35 concentration was at 800 or 1000 ppm, while for Brij 56 and Brij 58P, the highest inhibition was obtained when their concentrations were 500, 800, or 1000 ppm.

Corrosion behavior of high- and low-chromium steel grinding balls in chloride solution

The corrosion behaviour of three types of alloys (two low-alloy carbon steel and one stainless iron with ~15 wt.% Cr), in a solution which simulates seawater (3% NaCl solution, pH 8.1) was tested. Tested samples are used to make steel (iron) balls applied in mils for grinding copper and other ore. The corrosion tests were performed using three electrochemical methods, at room temperature in the presence of atmospheric oxygen. The linear polarization resistance (LPR) method, electrochemical impedance spectroscopy (EIS) method, and linear sweep voltammetry (LSV) method were applied. Based on measurements by LPR and EIS methods (as non-destructive methods), the value of polarization resistance (Rp) was determined and the general corrosion rate (vcorr) of the examined samples was calculated. The obtained values of the general corrosion rate can be used to calculate the service life of steel (iron) balls under exploitation conditions (seawater). The appearance of the surface after linear sweep voltammetry (LSV) measurement showed the presence of localized corrosion (pits were formed) of the tested samples, especially stainless iron, and the LSV method is not suitable for the determination of the general corrosion rate of tested samples in seawater. This form of corrosion occurs at high anodic polarizations, during performing LSV measurements.

The temperature dependence investigation of the frequency dispersion of the electrical properties of lithium-iron spinel doped with La, Y

The temperature-frequency dependences of the electrical characteristics of Li2 Fe2,5-x Mex O4 (Ме=La;Y, x=0.01; 0.03; 0.05) spinels synthesized by the «sol-gel» autocombustion technology were obtained by the method of impedance spectroscopy in the temperature range of 298-473 K.
 Based on their analysis, the main mechanisms of conductivity of these materials in the studied temperature range were identified: hopping and activation, which are competing. The effect of doping lithium-iron spinels with rare-earth metal impurities on these conductivity mechanisms has been investigated. It has been established that the presence of impurities in small concentrations in the synthesized samples significantly decreases their conductivity, mainly due to destruction of the hopping mechanism of electronic conductivity.

Green Ostrich fat waste extracts as a novel potential inhibitor to sustainable corrosion of steel in acidic environments: Electrochemical and DFT evaluation

The shift from traditional chemical corrosion inhibitors to green alternatives, focusing on plant extracts (GCIs), addresses environmental concerns in line with sustainable development goals. An innovative approach explores animal-derived extracts for eco-friendly corrosion inhibition, addressing environmental issues associated with conventional chemical inhibitors. Ostrich Oil, renowned for its nutritional, cosmetic, and pharmaceutical properties, is examined as a potential green corrosion inhibitor for C38 steel in 1 M hydrochloric. Extracted and characterized through GC-FID, Ostrich Oil exhibits corrosion protection analyzed via impedance spectroscopy, potentiodynamic polarization, and gravimetric methods. Complementary SEM and metallurgical microscopy with EDS offer surface insights. DFT and MD simulations explore the relationship between electronic properties and inhibition efficiency. Results show Ostrich Oil's significant corrosion inhibition (up to 94%), attributed to chemical adsorption of fatty compounds. The corrosion mechanism is influenced by Oil extract adsorption, increasing double electrochemical layer resistance. Gas chromatography identifies main compounds, and quantum chemical calculations highlight its reactivity. This research underscores the potential of animal-derived extracts, exemplified by Ostrich Oil, as effective and environmentally friendly corrosion inhibitors, contributing to sustainable corrosion protection practices.