Tafel Extrapolation Research Articles

Corrosion mitigation of carbon steel in sulfuric and hydrochloric acid solutions by Syzygium polyanthum (Wight) Walp. leaf extract

It is widely recognized that corrosion has been a persistent issue throughout human history. Over time, various effective strategies have been suggested and successfully employed to combat this problem. Among them, the utilization of inhibitors stands out as a promising, versatile, and easily applicable method. Considering the drawbacks associated with previous substances such as environmental concerns and high operational expenses, plant extracts have emerged as an effective alternative. In there, Syzygium polyanthum (Wight) Walp. stands out as a popular species characterized by a high concentration of polar compounds that is crucial for the formation of a protective film layer on carbon steel. Consequently, this work centers on investigating the corrosion inhibition behavior of Syzygium polyanthum (Wight) Walp. leaf water-extract (SPWE) for carbon steel in different solutions, including 1.0 M HCl, 0.5 M H2SO4, and co-volume acidic mixture, by employing electrochemical and surface techniques. The findings reveal that 2000 ppm of SPWE proved inhibition efficiency exceeding 94.24, 66.27, and 95.02% (estimated by Tafel extrapolation) for carbon steel in 1.0 M HCl, 0.5 M H2SO4, and acidic mixture solutions, respectively. High inhibition performance was also ensured by high polarization resistances (Rp) observed on electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR). Increasing corrosion resistance could be due to the protective layer formed on the inhibited samples, while severe corrosion occurred on the uninhibited steel due to extensive damage across the entire surface. Hence, the study underscores the noteworthy impact of chloride and sulfate ions on corrosive inhibition process of SPWE.

Quantitative Interpretation of Potentiodynamic Polarization Curves Obtained at High Scan Rates in Scanning Electrochemical Cell Microscopy.

Scanning electrochemical cell microscopy is becoming the tool of choice for the investigation of localized metal corrosion. Typically, potentiodynamic polarization measurements in scanning electrochemical cell microscopy are performed at high potential scan rates. However, Tafel extrapolation applied to high-scan-rate potentiodynamic polarization curves would yield inaccurate corrosion kinetics due to the interference of double-layer charging current or mass transport of species in the metal oxide. Instead, the high field model was used to simulate the potentiodynamic polarization curves of pure aluminum at 25, 50, 100, and 200 mV/s in neutral and acidic phosphate solutions, thus enabling quantitative analysis of local corrosion kinetics by fitting the potentiodynamic polarization curve.

Eco-friendly corrosion inhibition and scale control in seawater using Foeniculum vulgare and Pimpinella anisum extracts with chemical compounds

This study investigated the corrosion inhibition and scale control properties of both natural extracts and chemical inhibitors for C25 galvanized steel sheets with an 85-μm thick zinc coating steel exposed to seawater. The inhibitors, including Foeniculum vulgare (AF-Sha), Pimpinella anisum (AF-Sim), M640, and Veo, underwent rigorous evaluation through techniques such as Tafel extrapolation, potentiodynamic polarization analysis, concentration factor scale, seawater analysis, X-ray diffraction (XRD), infrared spectroscopy (IR), and conductivity-temperature analysis. Notably, AF-Sha and AF-Sim exhibited outstanding corrosion prevention capabilities, achieving inhibitory efficiencies of 87% and 85%, respectively. Comparative analyses with chemical inhibitors, M640 and Veo, demonstrated promising performance, positioning natural inhibitors as environmentally friendly alternatives. Corrosion rates, inhibition efficiency, and concentration factor scale results provided insights into the inhibitory effectiveness of each compound, with Veo showing superior performance. The study also explored the antiscalant behavior of inhibitors, revealing their ability to prevent corrosion and scale formation. XRD analysis indicated the impact of inhibitors on the crystal structure of scales, while IR spectra provided insights into vibration properties. Conductivity and temperature analyses illustrated the inhibitors' role in reducing ion exchange and gypsum concentration in seawater. These findings suggest that the inhibitors offered robust protection for ferrous metal surfaces and hold significant potential for practical applications. Additionally, our weight loss investigation extends this understanding, demonstrating the practical applicability of corrosion inhibitors like AF-Sha and AF-Sim in real-world scenarios. The presented results contribute significantly to the understanding of galvanized steel corrosion behavior in seawater, offering valuable insights for corrosion engineering applications.

Effect of post-processing on the corrosive behaviour of L-DED Ti-6Al-4V

The study investigates the effect of different post-processing techniques like annealing and cryogenic treatment on the corrosive behaviour on Laser direct energy deposited − Ti-6Al-4 V (LDED-Ti64). The investigation starts with LDED-Ti64 and cast-Ti64, one pair of samples are annealed at 800℃ for 2 h and the other pair of samples are Deep Cryogenic Treated(DCT) at −196℃ for 48 h. The electrochemical corrosion of all the samples are analysed through the tafel extrapolation technique. The results revealed that all the post-processed samples showed improvement in corrosion resistance, especially the annealed ones in comparison to the untreated sample. During annealing the martensitic α’-phases present in untreated samples get converted to β-phase which is a good corrosion inhibitor. During DCT the residual stress relieves and dislocation density improves which restrains electron flow and hence corrosion resistance improves.

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.

A Turn-Off Fluorescent Sensor for Metal Ions Quantifies Corrosion in an Organic Solvent

We demonstrate that the corrosion of AISI 1045 medium carbon steel and pure aluminum can be quantified by the turn-off fluorescent sensor Phen Green-SK (PGSK) in ethanol-based solutions. We first evaluate the dependence of the chelation enhanced quenching of PGSK on iron and aluminum ion concentrations. Subsequently, we apply PGSK to examine the anodic dissolution of metal corrosion. The observed time-dependent PGSK-quenching quantifies the corrosion rates of two metals over 24 h of immersion in ethanol-based solutions. The PGSK-based quantification of corrosion is compared to scanning electron microscopy and electrochemical techniques, including open circuit potential and Tafel extrapolation. The corrosion rates calculated from PGSK-quenching and Tafel extrapolation are in agreement, and both indicate a decrease in corrosion rates over 24 h. Our work shows PGSK can efficiently sense and quantify anodic corrosion reactions at metal interfaces, especially in organic solvents or other non-aqueous environments where the application of electrochemical techniques can be limited by the poor conductivity of the surrounding medium.

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.

Zirconium oxide thin films deposited via DC magnetron sputtering: corrosion and morphological investigation

Purpose The purpose of this study is to investigate the structural, surface roughness and corrosion properties of the zirconium oxide thin films deposited onto SS304 substrates using the direct current (DC) magnetron sputtering technique. Design/methodology/approach DC sputtering at different powers – 80, 100 and 120 W – was used to deposit ZrO2 thin films onto different substrates (Si/SS304) without annealing of the substrate. Atomic force microscope (AFM), energy-dispersive X-ray spectroscopy (EDS), Tafel extrapolation and contact angle techniques were applied to investigate the surface roughness, chemical compositions, corrosion behavior and hydrophobicity of these films. Findings Results showed that the thickness of the deposited film increased with power increase, while the corrosion current decreased with power increase. AFM images indicated that the surface roughness decreased with an increase in DC power. EDS analysis showed that the thin film has a stoichiometric ZrO2 (Zr:O 1:2) composition with basic uniformity. Water contact angle measurements indicated that the hydrophobicity of the synthesized films decreased with an increase in surface roughness. Originality/value DC magnetron sputtering technique is infrequently used to deposition thin films. The obtained thin films showed good hydrophobic and anticorrosion properties. Finally, results are compared with other deposition techniques.

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).

Microstructure and corrosion behavior of thermo-mechanically processed rare earth Mg alloy: Effect of friction stir processing

This study focuses on the application of friction stir processing (FSP) on a rare earth based WE43 magnesium alloy aiming to improve microstructure and corrosion resistance. Ultra-refined microstructure with an average grain size of 4 um was obtained due to plastic deformation in the FSPed specimen. Corrosion rate determined from Tafel extrapolation results for WE43 base alloy and FSPed samples are 2.31 mmpy and 0.938 mmpy respectively. The FSPed specimen showed improvement in corrosion behavior with increased uniformity in the protective passive layer and decreased occurrence of micro-galvanic coupling (pitting corrosion), which can be ascribed to the redistribution and fragmentation of second-phase particles.

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.

INVESTIGATION OF INHIBITORY EFFECT OF THE RASPBERRY FRUIT EXTRACT (Rubus idaeus L.) ON CORROSION OF COPPER IN 3% NaCl SOLUTION

<p>The paper presents an examination of the possibility of applying raspberry fruit extract (Rubus idaeus L.) as a green inhibitor of general corrosion of copper in 3% NaCl. Raspberry fruits (Rubus idaeus L.) sort Polka was collected from the Starposle near Kakanj, Bosnia and Herzegovina. Raspberry fruit extracts in ethanol were obtained by the Soxhlet extraction and the ultrasonic method. By UV/VIS spectrophotometry analysis, a significant content of polyphenols was found in the raspberry fruit extracts. Due to the great importance of gallic acid, the concentration of gallic acid was also determined using liquid chromatography. Corrosion testing of copper by the DC techniques was performed on a measuring device consisting of an electrochemical cell and a potentiostat/galvanostat, and electrochemical impedance spectroscopy measurements were performed using a potentiostat/galvanostat. Results obtained by the DC technique (by the method of Tafel extrapolation) prove that the corrosion rate decreases in the presence of the raspberry fruit extract. Tests performed by the method of electrochemical impedance spectroscopy prove that the tested extracts slow down the kinetics of the corrosion process, which is visible through the increase in resistance. The results of the conducted tests prove that in an aggressive medium, such as a 3% NaCl solution, Polka raspberry fruit extract can be used as an inhibitor of copper’s corrosion.</p>

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.

A sustainable approach exploiting Chrysanthemum Coronarium flowers distillation waste as a corrosion suppressor for low carbon steel in monoprotic acid medium through electrochemical and computational evaluations

This study focuses on evaluating a biowaste generated amid the hydrodistillation process of Chrysanthemum Coronarium Flower compounds as a sustainable inhibitor for the corrosion of carbon steel in the hydrochloric medium. Total phenolic and flavonoid contents, phytochemical screening protocols as well as Fourier Transform Infrared (FT-IR) analysis were implemented to examine the phytochemical diversity of the Chrysanthemum Coronarium flowers extract (CCFE). Electrochemical impedance spectroscopy (EIS) as well as Tafel extrapolation techniques were adopted for examining the corrosion suppression efficiency of the liquid waste as a corrosion inhibitor at 293 K. The findings indicated that the CCFE displayed strong corrosion suppression properties on the metal, achieving an impressive efficiency of 82 %. Following a mixed-type inhibition mechanism. Temperature influence in the presence of the CCFE was assessed at a 293–313 K domain, and the combined impact of KI and the CCFE inhibitor was investigated to determine their synergistic effects. Furthermore, an in-depth analysis of the surface morphology of metal was carried out using SEM-EDX analysis to investigate the electrochemical behavior and comprehend alterations occurring on the surface as a result of the CCFE introduction. Moreover, computational analysis through Density Functional Theory (DFT) and Molecular Dynamic simulations (MD) were performed to gain a more comprehensive understanding of the mechanism of electronic adsorption occurring at specific active sites in the presence of the Chrysanthemum Coronarium Flowers compounds.

Evaluation of Phosphopolyoxometalates with Mixed Addenda (Mo, W, V) as Corrosion Inhibitors for Steels.

Nowadays, choosing a corrosion inhibitor is not only based on efficiency, but must also consider the toxicity of the compound, the impact on the environment, and, obviously, the regulations in the field. In the last two decades, a special class of substances has begun to be studied, namely polyoxometalates (POMs). Their electronic properties and redox characteristics make the polyoxometalates potential candidates to be used in many electrochemical processes, and as potential corrosion inhibitors. Electrochemical methods such as a Tafel extrapolation plot, chronopotentiometry, or gravimetry have been used to establish the capacity of corrosion inhibition of S235 and SS304 steels in the presence of phosphovanadomolibdate acid (@PMoV) and phosphovanadotungstate acid (@PWV) in 0.5 M sulphuric acid solution. The inhibition efficiency for S235 steel is about 90.6% for @PMoV, and 69.5% for @PWV after 24 h of immersion. In the case of SS304 steel, polyoxometalates have similar effects: the inhibition degree, as a function of Flade potential, is 4.66 for @PMoV; better than 3.26 for @PWV, with both proving the passivant effect.

Development of trimetallic cobalt-nickel-vanadium oxide anticorrosion coatings for the protection of AA2024 Al alloy specimens against sodium chloride solutions

Trimetallic cobalt-nickel-vanadium oxide (CoNiVOx) thin films were fabricated on aerospace grade AA2024 Al alloy specimens to investigate their behavior as anticorrosion coatings in a sodium chloride (NaCl) medium. Compact and homogenous nanostructured CoNiVOx coatings were developed using aerosol-assisted chemical vapor deposition by varying the deposition duration from 45 to 150 min at a constant temperature (475 °C). The structure and composition of the trimetallic CoNiVOx thin films were comprehensively investigated using X-ray diffraction, transmission electron microscopy, scanning electron microscopy/energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy, which demonstrated the successful synthesis of CoO/NiO/VO composite materials. The electrochemical corrosion properties of the trimetallic CoNiVOx films in a 3.5 % NaCl solution were determined using Tafel extrapolation and impedance spectroscopic tests, whereas the electrochemical stability and localized corrosion characteristics were determined using scanning electrochemical microscopic analyses. This study demonstrates that the trimetallic CoNiVOx oxide layer fabricated for 150 min exhibited an effective barrier protection performance on Al surfaces against corrosive attack in NaCl media.

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.

Microstructural features and corrosion behavior of Inconel 625 components fabricated using Wire and Arc Additively Manufacturing (WAAM)

Wire and arc additive manufacturing (WAAM) is the predominant technique to process Nickel-based superalloys due to its low cost and high flexibility. This article discusses the microstructural features and corrosion resistance of two Inconel 625 parts manufactured using the WAAM technique. Using the WAAM process, two single-walled Inconel 625(IN625) components were produced additively for inter-pass layer temperatures (IPT) of 200 °C and 300 °C. The grain size changed with a change in IPTs, according to an investigation using electron backscatter diffraction (EBSD). The preferred grain orientation changed from the texture {001} < 001> to {001} < 101> as the IPT increased. Potentiodynamic polarization was used to evaluate the corrosion behavior. The corrosion rate of the IPT 300 °C sample is 0.007255 mmpy, while the corrosion rate of the IPT 200 °C sample is 0.01315 mmpy. Tafel’s extrapolation technique calculated the corrosion current density and corrosion current potential. The scanning electron microscope (SEM) explored the corroded area, and the energy-dispersive X-ray spectroscope examined the elemental composition.

Evaluation of the mechanical properties and corrosion behavior of hBN-Zn composite coatings on the weathering steel

Mechanical tests were conducted and analyzed to investigate the efficacy of Zinc-based coating methods enhanced with hexagonal Boron Nitride (h-BN) nanoparticles. Various methods are employed to deposit these coatings, including Zinc electroplating, Zinc hot-dip, and Zinc-rich coat (ZRC). Different parameters, such as plating time, temperature, voltage, pH, and concentrations of additives, are carefully selected during the process. The introduction of h-BN nanoparticles at varying concentrations into a Zinc- based coating significantly enhanced mechanical properties and performance measures. This improvement was achieved through the diffusion and dispersion of the nanoparticles within the coating. Furthermore, the incorporation of h-BN nanoparticles has exhibited notable enhancements in corrosion resistance when subjected to a 3.5% (NaCl) solution. The best microhardness and adhesion strength values can be achieved by increasing the h-BN concentration (1.5 to 2.5) wt.% in the plating baths. For instance, electroplating with h-BN at a concentration of 15.75 g/l yields a microhardness of 606.7 HV and an adhesion strength of 14.48 MPa. Similarly, hot dip galvanizing with h-BN at a concentration of 2.0% results in a microhardness of 542.1 HV and an adhesion strength of 10.28 MPa. Lastly, when using h-BN at a concentration of 2.5% in ZRC, the microhardness and adhesion strength values obtained are 557.8 HV and 8.5 MPa, respectively. The incorporation of h-BN nanoparticles resulted in a significant improvement and augmentation of the thickness of the coating exhibited the least amount of porosity and the most uniform dispersion when compared to other Zinc composite coatings, namely Zinc electroplating (with a thickness of 97 µm of h-BN at a concentration of 21 g/l), Zinc hot dip (with a thickness of 144 µm of h-BN at a concentration of 2.5%), and ZRC (with a thickness of 123 µm of h-BN at a concentration of 2.5%). Moreover, the utilization of Tafel extrapolation curves and corrosion analysis has demonstrated that Zinc- based coating techniques, when reinforced with the incorporation of h-BN, exhibit significantly improved corrosion current densities (icorr) and corrosion rates (CR). Zinc electroplating technique with h-BN at a concentration of 15.75 g/l yields current density and corrosion rate values of 0.72 µA/cm2 and 0.00659 mpy, respectively. Similarly, Zinc hot dip with a 2.0% h-BN concentration results in current density and corrosion rate values of 3.5 µA/cm2 and 0.032 mpy, while ZRC with a 2.5% h-BN concentration exhibits values of 5.2 µA/cm2 and 0.04758 mpy. OM, SEM, XRD, and EDS mapping analysis were used to characterize the Zinc composite coating's grain structure, grain size, nanoparticle distribution, and chemical composition. The coating matrix contained Zinc and h-BN nanoparticles without impurities. h- BN in the composite coating does not affect grain size. As nucleation sites, h-BN nanoparticles can reduce porosity and refine grains after integration. SubjectsMaterials Chemistry; Corrosion-Materials Science; Surface Engineering-Materials Science.

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.