Tafel Extrapolation Method Research Articles

Insight into anti-corrosion behavior of Cladanthus mixtus (L.) flower extracts as a biodegradable inhibitor for carbon steel in acid medium: Experimental and theoretical studies

This study conducted a comprehensive investigation into the corrosion inhibition potency of the essential oil of flowers (EOF) and the aqueous extract of flowers (AQEF), a by-product liquid waste derived from the extraction process of Clandanthus mixtus (L.), towards carbon steel in 1 M HCl. Phytochemical screening, gas chromatography (GC), and gas chromatography coupled to mass spectrometry (GC-MS) were employed to explore the chemical composition of the extracts. Flavonoids, tannins, and coumarins were identified as chemical families present in the extracts, while palmitic acid (10 %) and arcurcumene (39.1 %) were found to be the most important constituents, comprising 49.1 % of the total composition of the essential oil. Electrochemical techniques, including Tafel extrapolation methods and electrochemical impedance spectroscopy (EIS), were used to evaluate the inhibition efficiency of the extracts. The inhibition efficiencies reached a maximum of 80 % following a mixed-type inhibition mechanism. The temperature effect was evaluated, revealing a physisorption process followed by desorption at higher temperatures. The synergistic effect between the extract and potassium iodide was assessed at different doses, demonstrating their cooperative role in reducing steel surface deterioration. Surface micrographs were acquired through scanning electron microscopy (SEM) with the Energy Dispersive X-ray (EDX) method in the presence of AQEF, confirming the establishment of a protective barrier that mitigates the corrosive effects of hydrochloric acid. Additionally, this study employed Density Functional Theory (DFT) and Molecular Dynamics (MD) simulations to investigate the behavior of AQEF compounds against corrosion.

Oleaster Leaf Extract: A Potential Environmentally Friendly Inhibitor for Mild Steel

In this research, the potential of Elaeagnus angustifolia tree leaf extract as a green corrosion inhibitor for mild steel in hydrochloric acid solution was examined. The stock concentration of the aqueous extract was determined to be 0.38% (w/v). Other experimental solutions were created by diluting four different extract concentrations in aggressive solution. Experimental measurements, including linear polarization (LPR), electrochemical impedance spectroscopy (EIS), and semi-logarithmic current potential curves by Tafel extrapolation method, were employed to validate the corrosion inhibition effects of the plant leaf extract at varying concentrations. Notably, oleaster leaf extract demonstrated a corrosion protection of over 90% for 0.018% w/v concentration on the mild steel, attributed to its abundance in secondary metabolites such as polyphenols and flavonoids. The atomic force microscopy (AFM) surface maps provide robust evidence for the electrochemical measurement data.

Corrosion Behavior of Steel 37 under Dynamic Conditions in 0.1 N H2SO4

An aggressive environment has a substantial effect on the progression of corrosion on metal surfaces and alloys. This study investigated the effect of one of the parameters that affect the corrosion process, the stirring rate, on the behavior of Steel 37 in 0.1 N of sulfuric acid. The main method used in this study is an electrochemical method (using a potentiostat at a scan rate of 3 MV.sec-1), applied at three different temperatures (25, 30, and ˚C). To evaluate the parameters of corrosion in this study, the Tafel extrapolation method was used. At a constant stirring rate, the corrosion current density was found to be increased with increasing temperature at a constant stirring rate. In addition, the corrosion rate increased with increasing stirring rate at a constant temperature due to the rise of the diffusion coefficient of oxygen. The Levich equation was used to calculate the limiting current densities, as well as the mass transfer coefficient (Km) and the Sherwood number (Sh). The Km values were calculated and it was found that the mass transfer coefficient was greater at higher temperatures and stirring rates. The results also revealed that the smallest values of Sh (2.575, 3.897) occurred at 30 °C at two stirring rates (200 and 400 rpm).

Promising Eco-friendly Inhibitor Potency: Elaeagnus Angustifolia Leaf Extract for Mild Steel

In this research, the potential of Elaeagnus angustifolia tree leaf extract as a green corrosion inhibitor for mild steel in hydrochloric acid solution was examined. The stock concentration of the aqueous extract was determined to be 0.38% (w/v). Other experimental solutions were created by diluting four different extract concentrations in aggressive solution. Experimental measurements, including linear polarization (LPR), electrochemical impedance spectroscopy (EIS), and semi-logarithmic current potential curves by Tafel extrapolation method, were employed to validate the corrosion inhibition effects of the plant leaf extract at varying concentrations. Notably, oleaster leaf extract demonstrated a corrosion protection of over 80% for mild steel, even at low concentrations, attributed to its abundance in secondary metabolites such as polyphenols and flavonoids. The atomic force microscopy (AFM) surface maps provide robust evidence for the electrochemical measurement data.

Application of a new inhibitor for the corrosion of iron in acidic solution: Electrochemical effect of a scorpion venom

In this study, the venom of the species Leiurus abdullahbayrami, known as the yellow scorpion from the Buthidae family, was applied for the first time as a natural corrosion inhibitor for iron in hydrochloric acid solution. The effectiveness of scorpion venom as an eco-friendly and natural inhibitor was determined by electrochemical methods such as electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (Tafel extrapolation method) and linear polarization resistance (LPR) after an hour of immersion. Four different concentrations were determined for the green and natural inhibitor scorpion venom in 1.0 M HCl, and it was observed that the corrosion of iron in these solutions was significantly inhibited. In general, the inhibition efficiency was above 80%. According to the potentiodynamic polarization data, it has been determined that the Leiurus abdullahbayrami venom acts as a cathodic-type inhibitor on the Fe surface. Finally, the surface images of the iron electrodes in 1.0 M HCl solutions without and with Leiurus abdullahbayrami venom after 1 h immersion were examined by field emission scanning electron microscope (FE-SEM), it was concluded that the surface containing scorpion venom had a flatter compared to the uninhibited surface.

Synthesis of corundum rich coating on 7055 aluminum alloy by micro-arc oxidation and its corrosion resistant property in a saline medium

The work researched on Micro-arc oxidation (MAO) coatings fabrication method using 7055 aluminum alloy as substrate. The electrolyte was an alkaline solution added by sodium hexametaphosphate with/without sodium tungstate additive. X-ray diffraction (XRD) characterization proved that the α-Al2O3 (corundum)/γ-Al2O3 (gamma alumina) ratio in the coating reached 0.929 with trace tungsten metal, which was produced by thermit reaction. Scanning electron microscopy (SEM) characterization revealed craters up to 100 μm in diameter and micro-cracks on the coating surface. Energy dispersive X-ray spectroscopy (EDS) results indicated that the coating surface contains 0.74 at.% Mg, undetectable Zn and Cu, and 1.39 at.% Zr element, which should be 1.04 at.%, 1.51 at.%, 0.43 at.% and 0.02 % theoretically. Zr element distributed spatially in the same region with P element. The corrosion resistant property of the samples was analyzed by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization in 3.5 wt% NaCl. Tafel extrapolation method was utilized to analyze polarization curves and the results revealed that the corrosion potential of the MAO-treated sample was 0.016–0.093 V higher, and the corrosion current density was one order of magnitude lower (1/9.10–1/19.06) than the base 7055 aluminum alloy. The Nyquist diagrams of samples were modeled by equivalent electrical circuits through ZsimpWin software. The iterated data verified a three-layer structure of the MAO coating and the intermediate layer exhibited higher electrical resistance than the barrier layer. The coating film containing the most α-Al2O3 phase displayed the largest open porosity (3.99 % by calculation) and the highest electrical resistance. The friction test revealed that the coating fabricated under a higher current density possessed better wear resistance when the outer layer contacted the counterpair of Si3N4 ball.

Effect of Nb Addition on Corrosion Resistance of U-6Zr Alloys

The fuel element plates in a research reactor can be exposed to an acidic, neutral, or alkaline environment based on its surroundings. This study aimed to investigate the effect of Nb addition on the corrosion properties of U-6Zr alloys in various environments. U-6Zr-xNb alloys (U-6Zr-2Nb, U-6Zr-5Nb, and U-6Zr-8Nb) with different Nb compositions of 2, 5, and 8 wt%, respectively, were prepared and cut into smaller pieces. The pieces were then mounted with chemical resin equipped with copper wire cables and metallography prepared by grinding using sandpaper with grit sizes ranging from 320 to 1200. The electrochemical corrosion tests used in this work were the polarization test and Tafel extrapolation method. In the first step of corrosion testing, the corrosion potential and polarization resistance were measured using standard settings from a voltage range of −0.02 to 0.02 V with a scanning rate of 0.05 mV/s. In the next step, a destructive method, called the Tafel extrapolation method, was used. Corrosion tests were carried out on U-6Zr-xNb alloys (x = 2, 5, 8) under various environmental conditions using electrochemical methods. Polarization resistance test and Tafel extrapolation methods revealed that the U-6Zr-2Nb alloy exhibited good corrosion resistance in an acidic HNO3 environment with a pH of 1.18. The best corrosion resistance of the U-6Zr-5Nb alloy was observed in demineralized water. Meanwhile, the U-6Zr-8Nb alloy showed the best corrosion resistance in an alkaline NaOH environment with a pH of 11.02. It can be concluded that the higher Nb composition added to U-6Zr alloys, the better their corrosion resistance in higher pH environments.

Effect of different corrosive media on the corrosion resistance and mechanical properties of armor steel

Abstract Armor steel samples were exposed to corrosion for 24, 72, 168, and 720 h in two different corrosive media. The corrosion rate was determined using mass loss, measurement of the concentration of components in the corrosive medium solution, and Tafel extrapolation methods. Before and after corrosion experiments, the tensile properties, surface characteristics, and phase structures of the samples were examined. The surface analyses were performed using the SEM technique combined with EDX analyses, and the phase analyses were performed by X-ray diffraction. The corrosion rate determined by the mass loss method was 0.02 ± 0.01 mm year−1 for the 3.5 wt% NaCl medium and 2.66 ± 0.16 mm year−1 for the 1 M HCl medium. The corrosion rate values determined by the Tafel extrapolation method were 0.02 ± 0.01 mm year−1 in the 3.5 wt% NaCl medium and 1.21 ± 0.01 mm year−1 in the 1 M HCl medium. There was a decrease in the tensile, yield strengths, and elongation to fracture values of the corroded samples compared to the non-corroded samples. While intergranular ductile fracture occurred in samples exposed to 3.5 wt% NaCl medium, there were features reminiscent of the brittle fracture in samples exposed to the 1 M HCl/168 h medium.

Corrosion Resistance of Nanostructured Cemented Carbides with Alternative FeNi and FeNiCo Binders.

Nanostructured cemented carbides with Co binders have shown excellent mechanical properties in various applications. Nevertheless, their corrosion resistance has shown to be insufficient in different corrosive environments, leading to premature tool failure. In this study, WC-based cemented carbide samples with different binders were produced using 9 wt% of FeNi or FeNiCo with the addition of Cr3C2 and NbC as the grain growth inhibitors. The samples were investigated using electrochemical corrosion techniques: the open circuit potential Ecorr, the linear polarization resistance (LPR), the Tafel extrapolation method, and the electrochemical impedance spectroscopy (EIS) at room temperature in the solution of 3.5% NaCl. Microstructure characterization, surface texture analysis, and instrumented indentation were conducted to investigate the influence of corrosion on the micro-mechanical properties and the surface characteristics of the samples before and after corrosion. The obtained results indicate a strong binder chemical composition's effect on the consolidated materials' corrosive behavior. Compared to the conventional WC-Co systems, a significantly improved corrosion resistance was observed for both alternative binder systems. The study shows that the samples with the FeNi binder are superior to those with the FeNiCo binder since they were almost unaffected when exposed to the acidic medium.

Comparison of the Mechanical Properties and Corrosion Resistance of the Cr-CrN, Ti-TiN, Zr-ZrN, and Mo-MoN Coatings

In this work, the mechanical properties and corrosion resistance of Cr-CrN, Ti-TiN, Zr-ZrN, and Mo-MoN coatings deposited by the physical vapor deposition (PVD) method on Ti-6Al-4V alloy were compared. The phase composition of the coatings, their hardness and fracture resistance in scratch tests were determined, and their structural characteristics were also studied using a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The diffraction spectra were made using an automatic X-ray diffractometer. The value of the adhesive component of the friction coefficient fadh of the pair “coated and uncoated Ti-6Al-4V alloy” was investigated in the temperature range of 20–900 °C. The lowest value of fadh was detected for the Zr-ZrN coating at temperatures below 400 °C, while for the Mo-MoN coating it was observed at temperatures above 700 °C. The polarization curves of the coated and uncoated samples were performed in a 3% aqueous NaCl solution. The level of corrosion of the Ti-6Al-4V alloy samples with Cr-CrN, Ti-TiN, Zr-ZrN, and Mo-MoN coatings was evaluated using the Tafel extrapolation method, the iteration method, and the polarization resistance method. The results obtained with these methods indicate that the Zr-ZrN coated sample has the best corrosion resistance in the 3 wt.% NaCl solution, with a corrosion current density of 0.123 μA/cm2.

Corrosion and material properties of 316L stainless steel produced by material extrusion technology

Material Extrusion (ME) multi-step additive manufacturing of highly filled metal filament Ultrafuse 316L offers a notable alternative to cutting-edge additive technologies of metal alloys. It allows the creation of metal objects with debinding and sintering processes. Especially Powder Bed Fusion (PBF) technologies using laser or high-energy electron beams require costly maintenance, professional operators, and demanding process conditions during printing. On the other hand, such requirements do not incorporate ME printing.This study aims to comprehensively investigate and describe the behavior of material printed out of Ultrafuse 316L stainless steel filament on an affordable ME office-friendly printer. The main focus was on tests of fracture toughness, porosity, and corrosion resistance determined by the Tafel extrapolation method. The secondary objective was verifying the mechanical properties found in other studies (differing in results). For this purpose, several sets of fully dense samples were printed, debinded, and tested.

Corrosion Inhibition of Medium Carbon Steel in the Acidic Medium Using Alcoholic and Aqueous Extract of Kujarat Tea Plant

This study deals with the corrosion inhibition of metal corrosion process of medium carbon steel using 1M HCl for kinetic studies and rate reaction determination. The weight loss method is applied to pieces of Medium carbon steel divided to Cubans with dimensions (0.4*2*2.4) cm , and use Tafel Extrapolation Method, the samples were polished using carbide silicon paper with dimensions of (180,200,400,600,800,1000). The samples were immersed in the alcoholic medium ethanol at a temperature 293K for 3hr. Natural inhibitor Kujarat Tea (Hibiscus sabdarriffa L.) is used which is extracted in aqueous and alcoholic medium, different concentrations (1000،2000, 3000) ppm have been used ; The best concentration found through the results is a concentration found that is 1000 and 2000 ppm, the results indicate that the highest degree of inhibition for aqueous extract is 93.3% with the concentration of 2000 ppm and 90.5% with 1000 ppm at293K. While the alcoholic inhibitor shows the highest efficiency 92.4% with a concentration of 2000 ppm and 88.6% with a concentration of 1000 ppm respectively. The structure of the inhibitor was investigated using infrared spectroscopy (FTIR), and the surface morphology of the tested samples was investigated using a scanning electron microscope (SEM).

Uticaj ekstrakta polka maline (Rubus idaeus L.) na inhibiciju korozije bronze

Plant extracts contain a large number of organic compounds, and one of the large groups of compounds present are phenolic compounds. Researchers have shown that a certain number of these compounds can be used as effective metal corrosion inhibitors. Plant extracts of raspberries (leaves, flowers, and fruit) were obtained by ultrasonic extraction using 96% ethanol as a solvent. The UV/Vis spectrophotometric method was used to determine the content of total phenols in plant extracts. Phenolic acids and flavonoids in plant extracts were separated and quantified using the HPLC method. Tafel extrapolation was used for electrochemical characteristics. The corrosion characteristics and behavior of bronze in 3% NaCl solution, with and without the presence of plant extracts were investigated. The content of total phenols in leaves was found to be 107.14±3.63 mg/g in flowers 148.99±9.02 mg/g and in fruits was 8.75±0.61 mg/g. Leaf extract in a concentration of 0.04828 g/L according to the Tafel extrapolation method provides the best protection for bronze in a 3% NaCl solution. The same concentration in the case of flower and fruit extracts proved to be the most favorable.

Ptychostomum schleicheri (Bryophyta) Ekstraktının Yumuşak Çeliğin Korozyonu Üzerine Yeşil Önleyici Etkisi

In present study, the inhibitive impact of Ptychostomum schleicheri extract, a moss species of Bryaceae family, on the mild steel corrosion in 1 M HCl at ambient temperature was firstly analysed by Tafel extrapolation method, electrochemical impedance spectroscopy (EIS) and linear polarization (LPR) techniques. Electrochemical tests were conducted by 1 h immersing mild steels in HCl solutions containing four various concentrations of moss extract. At a concentration of 0.200% (w/v), the moss extract displayed around 90 percent inhibition efficiency by three electrochemical methods, and it was also observed that its protective effect increased depending on the upsurge in the concentration of Ptychostomum schleicheri extract. The morphologies of mild steels surface in 1 M HCl with and without P. schleicheri extract at the end of 1 h immersion time were visualized by a metal microscope. Finally, according to the electrochemical data and surface morphology results, it can be said that the extract molecules adsorbed on the mild steel surface to achieve almost maximal coverage and contact.

Characteristics of boronized Ti6Al4V alloy using boric acid based boronizing mixture

Boronizing processes of Ti alloys are generally performed in atmosphere-controlled furnaces. In this study, it is aimed to carry out boronizing process under atmospheric conditions by using an alternative boronizing mixture containing boric acid and to better the surface characteristics of Ti6Al4V alloy by boronizing. The efficiency of the boronizing mixture was evaluated by performing boronizing at different process temperatures (900-1100 °C) and durations (12 and 20 h). Microstructural (OM, SEM) and chemical (XRD, EDS, XPS) analyzes were performed to characterize the boride layers formed on the surfaces of the boronized samples. As a consequence of these analyzes, it was found out that a two-phase boride layer (TiB2 + TiB) was obtained in the samples. In addition, in vitro tests were done for specifying the bioactivity of boronized samples. In order to determine the effect of boronizing on the corrosion resistance of Ti6Al4V alloy, corrosion tests were performed by the Tafel extrapolation method. The adhesion behavior of the boride layers was determined by the Daimler-Benz Rockwell C indentation test. As a result, boronizing studies have been performed successfully without atmospheric-controlled conditions and it has been defined that surface characteristics of the Ti6Al4V alloy have bettered through the boride layers formed on the alloy surface.

Comparative study on electrochemical corrosion behavior of boronized X52 steel in 1 M HCl and H2SO4 solutions

This paper investigates the effect of boronizing treatment on the corrosion resistance of API X52 steel. Borides were grown on API X52 steel in a powder mixture containing 5% B4C as a boron source, 5% NaBF4 as an activator, and 90% SiC as diluents for 4 hours at 950 °C. X-ray diffraction (XRD) analysis revealed that the sample's boride layer contains only Fe2B phases. The corrosion behavior of borided and unborided specimens was investigated using the Tafel extrapolation method in 1M HCl and H2SO4 solutions. The results show that borided specimens have better corrosion resistance than unboronized specimens. The formation of layers of protective iron borides reduces the corrodability of the steel in the borided specimens. Boronizing increased the corrosion resistances of X52 steel in HCl and H2SO4 by 23 and 77-fold, respectively.

Synthesis of Cyano-Benzylidene Xanthene Synthons Using a Diprotic Brønsted Acid Catalyst, and Their Application as Efficient Inhibitors of Aluminum Corrosion in Alkaline Solutions.

Novel cyano-benzylidene xanthene derivatives were synthesized using one-pot and condensation reactions. A diprotic Brønsted acid (i.e., oxalic acid) was used as an effective catalyst for the promotion of the synthesis process of the new starting xanthene–aldehyde compound. Different xanthene concentrations (ca. 0.1–2.0 mM) were applied as corrosion inhibitors to control the alkaline uniform corrosion of aluminum. Measurements were conducted in 1.0 M NaOH solution using Tafel extrapolation and linear polarization resistance (LPR) methods. The investigated xanthenes acted as mixed-type inhibitors that primarily affect the anodic process. Their inhibition efficiency values were enhanced with inhibitor concentration, and varied according to their chemical structures. At a concentration of 2.0 mM, the best-performing studied xanthene derivative recorded maximum inhibition efficiency values of 98.9% (calculated via the Tafel extrapolation method) and 98.4% (estimated via the LPR method). Scanning electron microscopy (SEM) was used to examine the morphology of the corroded and inhibited aluminum surfaces, revealing strong inhibitory action of each studied compound. High-resolution X-ray photoelectron spectroscopy (XPS) profiles validated the inhibitor compounds’ adsorption on the Al surface. Density functional theory (DFT) and Monte Carlo simulations were applied to investigate the distinction of the anticorrosive behavior among the studied xanthenes toward the Al (111) surface. The non-planarity of xanthenes and the presence of the nitrile group were the key players in the adsorption process. A match between the experimental and theoretical findings was evidenced.

On the Tribocorrosion Behavior of Fe-Mn-Al-C Alloys in Ringer’s Solution

The long-term performance of steels is affected by the simultaneous actions of wear and corrosion, known as tribocorrosion. The tribocorrosion behavior of fully austenitic steels: Fe-Mn-xAl-C (x = 0, 3.5 and 8.3 wt.%) in Ringer’s solution was investigated by using a pin on disk tribometer adapted with a three-electrode corrosion cell. Open circuit potential and coefficient of friction evolution as well as polarization curves were measured. Corrosion rates were calculated by the Tafel extrapolation method, and wear rates were calculated by using a linear profilometer. Pure and total wear rates were higher for the 3Al alloy due to the greater precipitation and embedded calcium minerals, hydroxides, and oxides on the surface, to the detachment of the deformed layer and its adhesion to the counterbody. Additionally, the 8Al alloy exhibited the lowest tendency to corrosion and corrosion rate and the greatest synergistic effect, indicating that this alloy is more sensitive to this effect than the other alloys. For the three materials, the change in the wear rate due to corrosion had a greater contribution to the synergy than the change in corrosion rate due to wear and the damage in the materials was derived mainly from pure mechanical wear.

Tafel-Piontelli model for the prediction of uniform corrosion rate of active metals in strongly acidic environments

Corrosion represents a threatening and expensive problem for every industrial sector. To address this issue, several predictive models were developed and categorized in empirical, semiempirical and mechanistic, according to their underlying hypotheses, their representation of major physicochemical phenomena, and their applicability limits. In this work, a mechanistic model strongly based on the theory of kinetics of electrochemical corrosion is presented and validated. The model, called Tafel-Piontelli, was firstly proposed in 2017 as a tool for the calculation of the corrosion rate of active metals in acidic environments, characterized by hydrogen evolution as the dominant cathodic process. Starting from its initial version, the base-equation of the model has been revised and the theoretical architecture improved. The model was validated according to the experimental data collected for a variety of strong acids in a wide range of temperature and pH sets. The kinetic parameters of the equation, such as the cathodic Tafel slope and the hydrogen evolution exchange current density, were determined via cathodic potentiodynamic polarization tests (Tafel extrapolation method), while the iron ion activity and the corrosion rate were determined from mass loss tests and application of the Faraday law. The results show a remarkable improvement in the representation of the iron ion activity and of its exponential dependence on pH and temperature with respect to the original formulation. Additionally, the estimated corrosion rates accurately capture the dynamics observed in the empirical data, thus confirming the validity of the model.

INFLUENCE OF SIGMA PHASE ON GENERAL CORROSION OF AUSTENITIC STAINLESS STEEL

Austenitic stainless steel is mostly used at high temperatures. It is known that during heating of the austenitic stainless steel with increasing temperature and time of annealing a microstructure is changed i.e. there is the precipitation of carbides followed by precipitation of secondary phases as a sigma phase. The presence of the delta ferrite in austenitic stainless steel enhances the formation of the sigma phase. This study represents the influence of delta ferrite on the sigma phase formation and the effect of the sigma phase on general corrosion. Corrosion tests were conducted in the corrosion cell according to Standard ASTM G5, on instrument potentiostat/galvanostat, Princeton Applied Research, model 263A-2, with the software PowerCORR® (Standard, ASTM G5-94). Examinations were carried out in 1% HCl and 10% FeCl3 solutions. The Tafel extrapolation method was used for the investigation of general corrosion. The results of corrosion testing indicated that the intensity of the general corrosion increases with the increase of the delta ferrite and sigma phase contents.