Linear Polarization Resistance Techniques Research Articles

Electrochemical, thermodynamic and DFT studies of Fomitopsis pinicola as green corrosion inhibitor for carbon steel in sulfuric acid

In this work, the methanolic extract of Fomitopsis pinicola has been evaluated as a green corrosion inhibitor for the dissolution of 1018 carbon steel in 0.5 M sulfuric acid. For this, gravimetric tests and electrochemical methods such as potentiodynamic polarization curves, linear polarization resistance (LPR) and Electrochemical Impedance Spectroscopy (EIS) techniques were used. These tests were aided with Infrared and GC–MS analytical techniques. In addition to this, theoretical calculation with the use of the density functional theory (DFT) technique has been used to correlate the electronic extract properties and its inhibitory capacity. Weight loss results have shown an inhibitor efficiency of 85 % with the addition of 400 ppm. Thermodynamic parameters have shown that Fomitopsis pinicola extract is physically adsorbed onto the steel following a Langmuir adsorption isotherm. Potentiodynamic polarization curves showed that the extract behaves as a mixed type of corrosion inhibitor inducing the formation of a protective film onto the steel surface. In the presence of the Fomitopsis pinicola extract, a more resistive film obtained the highest polarization resistance value when 400 ppm of extract was used. In addition to this, as the concentration of the extract increased the charge transfer resistance and the double electrochemical layer capacitance decreased. GC–MS results indicated that main compounds contained in the Fomitopsis pinicola extract were Dehydrergosterol, Hydrazino-acetic acid ethyl ester, and Phthalic acid, di (2-propylpentyl) ester, whereas theoretical calculations showed that the highest EHOMO and lowest ELUMO values correspond to Dehydrergosterol and the Phthalic acid, which are the responsible for the extract inhibitory properties.

Corrosion of AISI1018 and AISI304 steel exposed to sulfates

This research analyses the behavior of corrosion, durability, and quality of reinforced concrete samples coated with two different materials when exposed to contaminated soil with sulfates. The initial assessment involved evaluating the water absorption rate of the coating materials before and after exposure to a solution containing 3% Na2SO4 + 3% MgSO4 + 3% K2SO4 + 3% CaSO4 to determine their durability. The corrosion potential and linear polarization resistance technique were employed to measure the corrosion rate. Carbon steel and AISI 304 steel bars were tested alongside a stainless counter electrode. The findings indicate that the solvent-based coating exhibited superior performance, demonstrating reduced corrosion and water absorption rates. Additionally, the presence of sulfates led to the formation of a surface layer on the concrete, initially aiding in limiting water penetration. However, over time, this layer eventually causes damage to the concrete from the inside out.

Effect of formic acid on aqueous corrosion mechanisms of mild steel

The effect of formic acid (HCOOH or shortly HFr) on corrosion mechanisms of X65 steel was systematically investigated in pH controlled, N2-sparged and CO2-sparged solutions using potentiodynamic polarization and linear polarization resistance (LPR) techniques. The results from the electrochemical experiments conducted in 1 wt.% NaCl solutions at 1 bar (total pressure) confirm that HFr is not significantly electroactive and therefore is not directly reduced on the steel surface under the conditions studied here. Experiments at various HFr concentration, temperature, pH, and flow rate also confirm that the main role of HFr on the corrosion of X65 steel is through the “buffering effect” mechanism. According to this mechanism, weak acids such as HFr increase the cathodic limiting current by providing hydrogen ions (H+) through their chemical dissociation similarly as is seen with acetic acid (CH3COOH or HAc).A comparison between HFr and HAc shows that these two organic acids have some differences in their behavior. First, HAc seems to retard the anodic reaction and decrease the corrosion rate, especially at lower temperatures and higher concentrations, while HFr does not. Second, the influence of these two acids on increasing the limiting current density seems to be similar at 30 °C, but at higher temperatures (50 °C, 80 °C), the cathodic limiting current density in the presence of HAc is greater than that with HFr at the same molar concentration. Under similar experimental conditions, HAc was observed to be less corrosive at lower temperature (30 °C), and more corrosive at higher temperatures (50 °C and 80 °C) compared to HFr at the same molar concentration.Experimental data collected in this study were used to validate a newly developed mechanistic model. According to our investigations this model shows an accurate fit to the experimental data at different HFr concentrations and pH at 30 °C. However, the model deviates from the experimental limiting current density value at higher temperatures (50 °C and 80 °C). It is speculated that this deviation results from a potential inaccuracy in the available temperature function for equilibrium constant of HFr dissociation reaction, which requires further investigations.

Protection of mild steel from corrosion in HCl solution via green Rumex acetosella extract: Experimental and theoretical studies

The efficiency and potential of green Rumex acetosella extract (RAE) on the inhibition of the mild steel (MS) corrosion were investigated in the acidic environment. The high inhibitive capability of RAE on the mild steel was studied by electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR) techniques. In addition, potentiodynamic (PD) polarization measurements were carried out to examine corrosion mechanism. The achieved electrochemical tests showed that RAE has a significant inhibition effect on mild steel corrosion. The results of surface analysis recorded by scanning electron microscopy (SEM), and atomic force microscopy (AFM) depicted that RAE provide strong protective layer on the steel surface via adsorptive groups. The inhibition efficiency was calculated as 99.7 %, and 99.6 % from LPR and EIS after 120 h exposure time. Adsorption free energy (∆Gadso) value is found as −29.79 kJ mol−1, indicating that both physical and chemical adsorptions occur. Furthermore, the obtained experimental findings were supported with quantum chemical calculation results.

Effects of Ca2+ Ions on the Localized Corrosion of Carbon Steel Influence of the Associated Anion

The corrosion rate of carbon steel under the attack of electrolytic mediums saturated by CO2 at a working temperature of 65 °C under dynamic conditions is studied in this paper. The effect of Ca2+ ions on corrosion rates and their dependency on the associated anion (Cl− or CO32−) with respect to the Ca2+ cation and Na+ are also assessed. A potentiostat/galvanostat associated with a rotor stator in an AISI 1040 steel-ring configuration, rotating at 600 rpm, was used. A linear polarization-resistance technique was applied to calculate the corrosion rate. It is found that the corrosion rate depends not only on the presence of Ca2+, but also on the salt anion added to the electrolytic medium. There was a strong inhibitory effect of the corrosion in the presence of Ca2+ in chloride-free mediums because of an ankerite deposition with a lower solubility compared to siderite. Moreover, it was observed that, even if the corrosion rate increased together with the Cl− concentration, its value depended on the cation introducing the anion. It was higher when Cl− was associated with Na+ compared to when it was associated with Ca2+. We found the following decreasing order in the carbon steel corrosion rate: 2% NaCl + 1380 ppm CaCl2 > 2% NaCl > 2% NaCl + 1360 ppm Na2CO3 > 2% NaCl + 1.25 g/L CaCO3 > 1450 ppm of NaCl > 1380 ppm CaCl2 > 1360 ppm Na2CO3 > 500 ppm CaCl2 > 424 ppm Na2CO3 >> 1.250 g/L CaCO3.

Green corrosion and DFT studies of Ustilago maydis extract for carbon steel in sulfuric acid

A study on the use of Ustilago maydis extract as a green corrosion inhibitor for 1018 carbon steel in 0.5 m H2SO4 by using gravimetric, potentiodynamic polarization curves, linear polarization resistance and electrochemical impedance spectroscopy electrochemical techniques at 25, 40 and 60 °C. Density functional theory (DFT) calculations were performed to know the relationship between inhibitor electronic properties and inhibition efficiency. Weight loss results indicated that Ustilago maydis was a good corrosion inhibitor with an efficiency that increased with its concentration but decreased with the temperature. However, the efficiency was around 60% because it was physically adsorbed on to the steel surface according to a Langmuir type of adsorption isotherm obtaining relatively low free energy values, which lied between −14.8 and −27 kJ/mol at 25 and 60 °C respectively. Activation energy decreased in presence of Ustilago maydis making corrosion process more difficult to occur. Potentiodynamic polarization curves showed a decrease in the corrosion current density in one order of magnitude and determined this extract as a cathodic type of corrosion inhibitor affecting. There was no evidence of a passive film, whereas the corrosion mechanism was controlled by the adsorption/desorption of some intermediate species and the double electrochemical layer resistance increased with the addition of the inhibitor. Gas chromatography showed that the main compounds found in this extract included D-Mannose, β-D-Glucopyranose,4-O-β-D-galactopyranosyl, Melibiose and Arabinose, whereas quantum chemical calculations by density functional theory analysis showed that Melibiose had the highest inhibition efficiency because it had the highest EHOMO value and lowest gap energy value, ∆E.

Sustainable and Green Approach for Api 5L Pipeline Steel Acidic Corrosion Inhibition Using Agro-Industrial Waste: Experimental and Theoretical

Currently, the use of synthetic inhibitors in preventing corrosion is destructive to the environment; therefore, natural inhibitors might be an alternative and innovative solution to this challenge, owing to their sustainability. Herein, wasted avocado seed extract was examined as a sustainable and green inhibitor for API 5L X65 pipeline steel at an ambient temperature using the gravimetric analysis, the potentiodynamic polarization curve, and linear polarization resistance techniques. The inhibitor’s chemical characterization was carried out with Fourier-transform infrared spectroscopy (FTIR), and the morphological characterization was carried out by detailed scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDX). The result showed that the extract decreased the corrosion rate by retarding the cathodic and anodic electrochemical reactions, with a maximum efficiency of 88% at 5 g/L. The extract was adsorbed physically onto the X 65 steel following the Langmuir adsorption isotherms. The electrochemical studies showed that the agro-waste was a mixed-type inhibitor. The SEM image of the X65 steel with the extract showed thin film formation on the steel surface. The extract can be substituted for synthetic inhibitors, which are toxic, scarce, and costly.

Application of solar photovoltaic electricity in unravelling the effects of coating defects on cathodic protection parameters of buried pipeline

Corrosion management in some remote locations such as Niger Delta region of Nigeria, is at risk of uncertainty of constant power supply. Thus, solar photovoltaic (PV) presents a sustainable alternative to conventional fossil energy in mitigating pipeline failure, associated human and material harzards and other environmental exposures. Coating defects takes place when the surface of the structure is cathodically exposed. An epoxy coating was applied on the X65 carbon pipeline powered with four (4) solar PV modules to charge a 200Ah battery to generate a direct current (DC) and to detect defects initiated on the coated pipe. Linear Polarization Resistance (LPR) technique was adopted in assessing cathodic protection (CP) parameters of the coated pipe. The result shows that current flow decreased with an increase in the size of the defect. Resistance to CP was found to be 12354263.07 Ohm.cm2 compared with no CP of 87174 Ohm.cm2 at 0.1 cm2 scratch size. By implication, the application of coating with CP in the absence of defects was observed to significantly increase cathodic current. This is otherwise known as overprotection, a situation that enhances hydrogen embrittlement and coating disbondment.

Effect of different types of calcined crude kaolins and high purity metakaolin on corrosion resistance of reinforcement in concretes: Experimental evaluation and analytical modeling

In this experimental study, the corrosion characteristics of steel reinforcement bars embedded in concretes, which were produced by incorporation of metakaolin obtained from high purity metakaolin or calcined raw kaolins, were investigated. The linear polarization resistance (LPR) method was benefited as the corrosion monitoring method. In concrete production, 0.40 water/binder ratio, 350 kg/m3 total binder amount, two different mineral admixture replacement levels of 5% and 15% were used. In addition, control samples were produced to evaluate the effectiveness of mineral additives. Reinforced concrete samples manufactured for accelerated corrosion monitoring were submerged into NaCl solutions of two different concentrations (2% and 5% solutions) to provide rapid anodic reactions in corrosion process. Additionally, the electrical resistance values of the concretes were tested to assess the corrosion behavior. After the experimental results were achieved, the obtained data were evaluated statistically and a new mathematical estimation model was developed using the gene-expression programming (GEP) method taking into account the effective parameters. This model was also compared with the results of the multiple linear regression, which is a statistical method. The analysis of the results based on LPR technique showed that the modified samples yielded higher corrosion resistance than the plain samples in both solution exposure conditions. Among the mineral additives used, it was observed that those with metakaolin addition had the highest resistance. While the coefficient of determination (R2) of the testing set produced for the GEP prediction model was around 0.9, the value obtained by multiple linear regression was found to be 0.433.

Effect of Damage on the Corrosion Performance of Thermal Spray Aluminium (TSA) Coating in Synthetic Seawater

A widely used coating system for corrosion mitigation of offshore steel structures is thermally sprayed aluminium (TSA). Even though these coatings have been used for decades, it is not always clear how they perform in service over long periods, particularly if damaged during installation or in service. To understand the corrosion behaviour of damaged TSA coatings in seawater and their tolerance to levels of damage, TSA coatings (1050 Al) were prepared on carbon steel substrates using wire arc spray and tested in synthetic seawater. Prior to testing, various levels of holidays or damage (~5%, 10%, 15% and 18%) reaching the steel substrate were drilled on the front surface of the coated specimens. Open circuit potential was measured and linear polarization resistance technique was used to calculate the corrosion rate. The work showed that the TSA coatings polarised steel to potentials below −800 mV (Ag/AgCl) at 25 °C, even in the presence of damage or holiday (up to ~18%). The SEM/EDX and XRD data confirmed the presence of brucite and aragonite in the damage region. The presence of damage impacted the short-term corrosion rate at the start, but did not significantly affect the overall corrosion performance of the TSA coatings in 420 days of testing.

A new 1,2,4-triazole derivative as an excellent corrosion inhibitor: Electrochemical experiments with theoretical validation

In the present investigation a triazole derivative, 4-{(E)-[(4-hydroxy-3-methoxyphenyl)methylidene]amino}-5-(pyridin-4-yl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (HMPT) has been synthesized. The inhibition efficacy of HMPT has been studied on carbon steel in 1 M hydrochloric acid solution by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization techniques (PDP), electrochemical frequency modulation (EFM), and linear polarization resistance (LPR) techniques. The results revealed that HMPT has significant inhibitory effects for the corrosion of carbon steel in an acid medium and displayed around 95% inhibition efficiency at optimum HMPT concentration with decrease in the current density value from 279.9 μA/cm2 to 153.8 μA/cm2. PDP studies signified mixed-type inhibition of HMPT. The mechanism of inhibition is believed to be occur by the adsorption of HMPT on the carbon steel surface and obeyed Langmuir adsorption isotherm. The values of Gibbs free energy of adsorption indicated that the adsorption of HMPT molecules on carbon steel takes place by both physical and chemical adsorption processes. The SEM/EDX studies confirmed the adsorption of HMPT on the carbon steel surface. The quantum chemical studies have provided good support to the experimental results. The promising results indicate the proposed inhibitor HMPT as a possible corrosion inhibitor for protecting the metallic components effectively from corrosion.

Corrosion initiation and its effect on bond characteristics and service life of reinforced concrete systems with Cement-Polymer-Composite coated steel rebars

This paper investigates the corrosion and bond characteristics of steel reinforcement with Cement-Polymer-Composite (CPC) coating, which is widely used worldwide to prolong the initiation of corrosion. CPC coating is supposed to be applied on sandblasted or cleaned surface to exploit its full potential. However, CPC coating is generally applied on the rusted or uncleaned surface, which can lead to premature corrosion initiation and associated degradation of the bond between coated steel and concrete. For corrosion studies, 20 lollipop specimens with as-received and sandblasted steels, and with and without CPC coating were cast. These were exposed to chlorides and tested using a recently developed test method based on the linear polarization resistance technique. It was found that as-received, CPC coated steels had 50% less chloride threshold than sandblasted, CPC coated steel. For bond studies, 16 pull-out specimens with CPC coated steel rebars were cast. It was found that even negligible corrosion can lead to ≈50 to 70% reduction in bond strength. This indicates that the corrosion propagation period in the case of CPC coated rebar systems would be negligible. Based on the corrosion and bond results, a new service life model for RC systems with CPC coated steel rebars is proposed. The results highlight that if preventive maintenance is not employed, many structures with CPC coated rebars can experience premature corrosion initiation and significant bond reduction.

Corrosion Inhibition Evaluation of Chitosan–CuO Nanocomposite for Carbon Steel in 5% HCl Solution and Effect of KI Addition

Chitosan–copper oxide (CHT–CuO) nanocomposite was made by an in-situ method utilizing olive leaf extract (OLE) as reductant. The OLE mediated CHT–CuO nanocomposite containing varying amount of chitosan (0.5, 1.0 and 2.0 g) was evaluated as corrosion inhibitor for X60 carbon steel in 5 wt% hydrochloric acid solution. The corrosion inhibitive performance was assessed utilizing weight loss and electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic polarization techniques complemented with surface assessment of the corroded X60 carbon steel without and with the additives using scanning electron microscopy/energy dispersive X-ray spectroscopy and 3D optical profilometer. The effect of KI addition on the corrosion protection capacity of the nanocomposites was also examined. Corrosion inhibitive effect was observed to increase with increase in the nanocomposites dosage with the highest inhibition efficiency (IE) achieved at the optimum dosage of 0.5%. The order of corrosion inhibition performance followed the trend CHT1.0–CuO (90.35%) > CHT0.5–CuO (90.16%) > CHT2.0–CuO (89.52%) nanocomposite from impedance measurements. Also, IE was found to increase as the temperature was raised from 25 to 40 °C and afterwards a decline in IE was observed with further increase in temperature to 50 and 60 °C. The potentiodynamic polarization results suggest that the nanocomposites alone and in combination with KI inhibited the corrosion of X60 carbon steel by an active site blocking mechanism. Addition of KI upgrades the IE of the nanocomposites but is not attributable to synergistic influence. The lack of synergistic influence was confirmed from the computed synergism parameter (S1) which was found to be less than unity with values of 0.89, 0.74 and 0.75 for CHT0.5–CuO, CHT1.0–CuO and CHT2.0–CuO nanocomposites, respectively, at 60 °C. Furthermore, KI addition improved the IE with rise in temperature from 25 to 60 °C. Surface analysis results confirm the formation of a protective film which could be attributed to the adsorption of the nanocomposites on the carbon steel surface.

The role of some triazoles on the corrosion inhibition of C1020 steel and copper in a desalination descaling solution

The effect of molecular structure on the performance of three triazole derivatives namely benzotriazole (BZT), 5-methyl-1H-benzotriazole (5MBZT), and 3-amino-5-methylthio-1H-1,2,4, triazole (3AMT) as corrosion inhibitors for C1020 steel and pure copper in 2% hydrochloric acid (HCl), which simulate descaling process in a typical desalination plant was investigated. Electrochemical characterization such as electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), linear polarization resistance (LPR) techniques and theoretical simulations were utilized in this study. The electrochemical characterization results showed that the order of inhibition efficiencies for the inhibitors was a function of the type of metal, molecular structure, and immersion time. For instance, for C1020 steel, the order of inhibition efficiency using EIS data was 5MBZT (91.8%) > BZT (78.1%) > 3AMT (24.8%) after 24 h of immersion. On the other hand, for pure copper, the order of inhibition efficiency with the same EIS data was 3AMT (93.0%) > 5MBZT (92.1%) > BZT (90.4%) after 24 h of immersion indicating the role of different metallurgy on corrosion protection. The theoretical results provided molecular level insights on the nature and the active sites of the corrosion inhibiting species as well as the energetics of the adsorption process on steel and copper.

Insight into the Elemental Sulfur Corrosion of Carbon Steel in Chloride Bearing Media Using Electrochemical and Non-electrochemical Techniques

This paper studies elemental sulfur-induced corrosion of carbon steel in chloride bearing media. The issue is of great importance in industries dealing with sour gas environment and its mechanism is yet not entirely understood. The aim of this study was sought using various electrochemical (such as potentiodynamic polarization, linear polarization resistance technique, electrochemical impedance spectroscopy and zero resistance ammeter technique) and non-electrochemical techniques (such as scanning electron microscopy and Raman spectroscopy). It was found that reduction of dissolved oxygen is not the main cathodic reaction in the process of the sulfur-induced corrosion. Besides, severe corrosion primarily occurs at near peripheral region of sulfur deposition, leading to formation of a ring of FeS. However, the FeS accumulation reduces the corrosion rate, over the time. In the long term, a galvanic couple is established between the near peripheral and remote regions of the sulfur deposition. Occurrence of the consequent galvanic corrosion could cause severe corrosion at the regions which are far from the sulfur deposition and are not influenced by the sulfur-based species.

Corrosion Resistance Measurement of 316L Stainless Steel Manufactured by Selective Laser Melting.

Selective laser melting (SLM) technology is ushering in a new era of advanced industrial production of metal components. It is of great importance to understand the relationship between the surface features and electrochemical properties of manufactured parts. This work studied the influence of surface orientation on the corrosion resistance of 316L stainless-steel (SS) components manufactured with SLM. The corrosion resistance of the samples was measured using linear polarization resistance (LPR) and electromechanical noise (EN) techniques under three different environments, H2O, 3.5 wt.% NaCl, and 20% H2SO4, analyzing the horizontal (XY) and vertical (XZ) planes. The microstructure and morphology of the samples were obtained by optical (OM) and scanning electron microscopy (SEM). The obtained microstructure showed the grains growing up from the fusion line to the melt pool center and, via SEM-EDS, the presence of irregular and spherical pores was observed. The highest corrosion rate was identified in the H2SO4 solution in the XZ plane with 2.4 × 10−2 mm/year and the XY plane with 1.31 × 10−3 mm/year. The EN technique along with the skewness factor were used to determine the type of corrosion that the material developed. Localized corrosion was observed in the NaCl electrolyte, for the XY and XZ planes (−1.65 and −0.012 skewness factors, respectively), attacking mainly the subgrains of the microstructure and, in some cases, the pores, caused by Cl ions. H2O and H2SO4 solutions presented a uniform corrosion mechanism for the two observed orientations. The morphology identified by SEM was correlated with the results obtained from the electrochemical techniques.

N1,N1,N12,N12-Tetramethyl-N1, N12-dioctyldodecane-1,12-diaminium bromide: Its synthesis and application in inhibition of mild steel corrosion in 15% HCl

A bis-quaternary ammonium bromide, N1,N1,N12,N12-tetramethyl-N1,N12-dioctyldodecane-1,12-diaminium bromide (TDAB) was successfully synthesized and characterized with the elemental analyzer, FTIR, TGA, 1H, and 13C NMR. Electrochemical frequency modulation (EFM), electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), potentiodynamic polarization (PDP), and weight-loss techniques were used to evaluate the corrosion inhibition performance of TDAB in a 15% HCl solution. TDAB showed an inhibition efficiency of ≈95% at 25 °C and an average of 90% at 45 °C and 60 °C at 311.17 µM. The thermodynamic parameters estimated values of ΔG0mics, ΔG0ads, ΔH#ads, and Ea was found to reveal typical behavior of physisorption of TDAB on mild steel, support unimolecular reaction, and obeyed Langmuir isotherm model. The ability of low concentration (15.56 µM) of TDAB to undergoes synergistic interaction with iodide ion was predicted (SI = 1.92). SEM and XPS analysis confirmed the adsorption of the TDAB molecule on mild steel.

Efficacious Alkaline Copper Corrosion Inhibition by a Mixed Ligand Copper(II) Complex of 2,2′‐Bipyridine and Glycine: Electrochemical and Theoretical Studies

AbstractA mixed ligand copper(II) complex, namely, [Cu(BPy)(Gly)Cl]⋅2H2O (CuC) (BPy=2,2′‐bipyridine and Gly=glycine), was synthesized and characterized. The synthesized CuC complex was tested as inhibitor to effectively mitigate the corrosion of copper in alkaline solutions using the linear sweep voltammetry (LSV) and linear polarization resistance (LPR) techniques. For the sake of comparison, such two D.C. electrochemical techniques were also applied to the Cu/OH− interface in the presence of the two studied free ligands, namely, BPy and Gly. The results showed that the three studied compounds acted as mixed‐type inhibitors, with CuC being the most efficacious one. The adsorption of the inhibitor is confirmed from X‐ray photoelectron spectroscopy (XPS) profiles by the appearance of organic chlorine as well as pyridine and amine nitrogen bonds. Based on XPS data, it was presumed that the corrosion inhibitor stimulates the formation of Cu2CO3(OH)2 species at the electrode surface since, in the case of a corroded reference sample (in absence of inhibitors), its proportion is trivial. The reactivity of the isolated inhibitors was analyzed by computing several quantum chemical parameters based on the density functional theory (DFT). A good correlation was found between these parameters and the anticorrosive performance. Additionally, Monte Carlo simulation studies were applied to find the best configurational space of ligands and their complex on the Cu(111) surface.

Application of LPR and EIS techniques for on‐site corrosion monitoring at the geothermal plant in Central Poland

AbstractCorrosion monitoring station was installed at ‘Geotermia Mazowiecka’ geothermal plant in Poland. Linear polarisation resistance and electrochemical impedance spectroscopy techniques were applied to estimate the corrosion rate and the surface changes of K55 carbon steel, L80‐13CR and 316 stainless steels directly in the geothermal water flux. The enhanced corrosion of K55 carbon steel and corrosion rate of L80‐13CR and 316 stainless steels was observed. The formation of biofilm increased the resistivity of the surface.

Improvement of in vitro corrosion, wear, and mechanical properties of newly developed Ti alloy by thermal treatment for dental applications

Abstract The effects of thermal treatments on the structure, mechanical properties, wear resistance, and in vitro corrosion protection in artificial saliva (AS) were investigated for a newly developed Ti20Nb13Zr (TNZ) alloy. XRD and SEM analyses were used for structural and microstructural analysis. The in vitro corrosion properties of the samples were investigated using electrochemical impedance spectroscopy and linear polarization resistance techniques up to an immersion time of 168 h. The tribological characteristics were evaluated with a linear reciprocating tribometer. SEM analysis showed that solution treatment and aging influenced the size and distribution of α phase. The air-cooled and aged samples exhibited the highest microhardness and macrohardness, for which the wear resistances were 25% and 30% higher than that of the untreated sample, respectively. The cooling rate significantly influenced the corrosion resistance of the TNZ samples. The treated samples showed a reduced corrosion rate (50%) for long immersion time up to 168 h in AS. The furnace-cooled and aged samples exhibited the highest corrosion resistance after 168 h of immersion in AS. Among the treated samples, the aged sample showed enhanced mechanical properties, wear behavior, and in vitro corrosion resistance in AS.