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Öğe Dynamic electrochemical impedance spectroscopy and polarization studies to evaluate the inhibition effect of benzotriazole on copper-manganese-aluminium alloy in artificial seawater(Wiley-V C H Verlag Gmbh, 2013) Gerengi, Hüsnü; Slepski, Pawel; Bereket, GözenThe effect of benzotriazole (BTA) on the corrosion of a new type copper-manganese-aluminium (CMA) alloy in artificial seawater was investigated using dynamic electrochemical impedance spectroscopy (DEIS), linear polarization resistance, and Tafel extrapolation methods. Measurement results obtained from those three methods showed that corrosion rates decreased while BTA concentration increased. This clearly indicates that BTA inhibits the corrosion rate of CMA in artificial seawater. Although there are consistent results obtained from all these three methods, the results of the percent inhibition efficiency, IE (%), values obtained from DEIS method should be calculated from the charge transfer resistance (R-ct) values obtained after 5h.Öğe Evaluation of corrosion inhibition of brass-118 in artificial seawater by benzotriazole using Dynamic EIS(Pergamon-Elsevier Science Ltd, 2009) Gerengi, Hüsnü; Darowicki, Kazimierz; Bereket, Gözen; Slepski, PawelThe paper presents the results of corrosion behaviour of brass-118 in artificial seawater and the inhibitor effect of benzotriazole (BTA) by using a novel method called dynamic electrochemical impedance spectroscopy (DEIS). This method allows the tracing of the dynamics of the corrosion and the inhibition process based on the evaluation of electrical parameters of the equivalent circuit. Instantaneous impedance spectra recorded up to 10 h show that an exposure of few hours is not enough for the determination of inhibition efficiency. The results indicate the usefulness of DEIS technique in the field of inhibitor research. (C) 2009 Elsevier Ltd. All rights reserved.Öğe Improved Performance of 1-Ethyl-3-Methylimidazolium Tetrafluoroborate at Steel/HCl Interface by Iodide Ions(Springer International Publishing, 2018) Gerengi, Hüsnü; Solomon, Moses M.; Umoren, Saviour A.; Uğraş, H. İbrahim; Yıldız, Mesut; Slepski, PawelThe corrosion and corrosion inhibition of St37 steel in 0.1 M HCl solution by 1-ethyl-3-methylimidazolium tetrafluoroborate (EMITFB) and the effect of addition of KI on the inhibitive performance of EMITFB have been examined by electrochemical [electrochemical impedance spectroscopy, potentiodynamic polarization, and dynamic electrochemical impedance spectroscopy (DEIS)] and surface examination [scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS)] techniques. Results show that EMITFB could only afford the protection of St37 steel in HCl medium on an average scale. The highest studied concentration of EMITFB (4 mM) affords optimum inhibition efficiency of 78.86% from DEIS method. Addition of iodide ions to EMITFB has beneficial effect on the inhibition efficiency; 86.10% has been achieved by addition of 1 mM KI to 4 mM EMITFB. Adsorption of EMITFB molecules onto the metal surface is via physical adsorption mechanism and follows El Awady et al. kinetic/thermodynamic adsorption isotherm model. SEM and EDS results confirm the improvement of corrosion inhibiting ability of EMITFB by iodide ions. EMITFB and EMITFB + KI behave as mixed-type corrosion inhibitor in the studied environment. © 2018, Springer International Publishing AG, part of Springer Nature.Öğe The Inhibition Effect of Mad Honey on Corrosion of 2007-Type Aluminium Alloy in 3.5% NaCl Solution(Univ Fed Sao Carlos, Dept Engenharia Materials, 2014) Gerengi, Hüsnü; Göksu, Haydar; Slepski, PawelThe inhibition effect of mad honey on corrosion of 2007-type aluminium alloy in 3.5% NaCl solution was investigated by Tafel extrapolarisation (TP), electrochemical impedance spectroscopy (EIS) and dynamic electrochemical impedance spectroscopy (DEIS). All the studied parameters exhibited good anti-corrosive properties against corrosion of 2007-type aluminium alloy in the test solution; the corrosion rates decreased with the increase of the mad honey concentration. The surface morphology of the alloy was examined under scanning electron microscopy (SEM) in the absence and presence of the inhibitor. The inhibitory adsorption processes of mad honey on the 2007-type aluminium alloy surfaces conformed to the Langmuir adsorption isotherm.Öğe Instantaneous Impedance Analysis of Non-Stationary Corrosion Process: a Case Study of Carbon Steel in 1M HCl(Esg, 2017) Ryl, Jacek; Gawel, Lukasz; Cieslik, Mateusz; Gerengi, Hüsnü; Lentka, Grzegorz; Slepski, PawelThe paper concerns the problem of evaluation of stationarity of carbon steel corrosion in 1M HCl. Comparison of corrosion rate with addition of corrosion inhibitor to the reference measurement is the most often used way of evaluating inhibitor efficiency. Such an approach is valid only if corrosion rate is a stationary process. Two complementary techniques were used simultaneously: volumetric analysis of evolved hydrogen and instantaneous impedance spectroscopy monitoring. Changes of the electrode surface area and chemical composition have a major impact on the dynamics of both cathodic and anodic processes. On the base obtained results, authors claim that the stationarity of the process determined most often on the base of corrosion potential is ineffective and insufficient.Öğe Investigation effect of benzotriazole on the corrosion of brass-MM55 alloy in artificial seawater by dynamic EIS(Springer, 2010) Gerengi, Hüsnü; Darowicki, Kazimierz; Slepski, Pawel; Bereket, Gözen; Ryl, JacekThe electrochemical behavior of brass-MM55 alloy was studied in artificial seawater with benzotriazole by using a novel method called dynamic electrochemical impedance spectroscopy (DEIS). This method gives possibility to investigate the protection of metals in corrosive medium by using inhibitors in galvanostatic conditions for a long time. Instantaneous impedance spectra for brass-MM55 were recorded for 10 h in artificial seawater for different concentration of benzotriazole. It was found that a few hours were not enough for the accurate calculation of corrosion inhibition. Also with this method it is possible to figure out how the charge transfer resistance (R (ct)) changes by the time. Usefulness of the DEIS technique in the investigation of non-stationary phenomena has been proved in the field of inhibitor research. All studies clearly show that benzotriazole inhibits the corrosion of brass-MM55 alloy in artificial seawater solution and the value of inhibition efficiency increases with increasing concentration of benzotriazole.Öğe Investigation of corrosion behavior of 6060 and 6082 aluminum alloys under simulated acid rain conditions(Wiley-V C H Verlag Gmbh, 2015) Gerengi, Hüsnü; Slepski, Pawel; Özgan, Ercan; Kurtay, MineInstantaneous impedance changes of 6060 and 6082 type aluminum alloys in pure water, and simulated acid rain poured into the pure water was investigated by dynamic electrochemical impedance spectroscopy (DEIS). In this way, the influence of aluminum content on the corrosion behavior of 6060 and 6082 type aluminum alloys immersed in simulated acid rain was determined. The corrosion rate of the alloy decreased with increasing Al content, which may be related to the distribution of the Al-rich phase. The surface morphology of studied alloys was also examined with scanning electron microscopy.Öğe New Method of Non-Linear Electrochemical Impedance Spectroscopy with an Amplitude-Modulated Perturbation Signal(Electrochemical Soc Inc, 2019) Slepski, Pawel; Szocinski, Michal; Majcherczak, J.; Gerengi, Hüsnü; Darowicki, K.The paper presents a new method of non-linear electrochemical impedance spectroscopy (NLEIS), which allows fast and non-destructive evaluation of the corrosion rate and determination of the Tafel coefficients values for a corrosion system under investigation. This method employs amplitude modulation of the ac perturbation signal. The study demonstrated that it was possible to obtain impedance characteristic as a function of the perturbation signal amplitude based only on a single measurement. The investigations were carried out on carbon steel exposed to 1M KCl solution, which is a model corrosion system with cathodic control. The values of corrosion current and Tafel coefficients values for the corrosion reaction were determined using the dependence between the charge transfer resistance and the amplitude of the perturbation signal. (C) 2019 The Electrochemical Society.Öğe A Probe into the Corrosion Behavior of a WE43B Magnesium Alloy in a Simulated Body Fluid using Dynamic Electrochemical Impedance Spectroscopy(Springer, 2023) Gerengi, Husnu; Lorenzi, Sergio; Solomon, Moses M.; Slepski, Pawel; Gratton, Sara; Cabrini, MarinaWE43B is one of the newest Mg alloys with practical application in biomedical implant technology. This work attempts to scrutinize the corrosion characteristics of WE43B alloy in a simulated body fluid (SBF) at a typical body temperature. The dynamic-electrochemical impedance spectroscopy with the capacity to track changes on surfaces in a dynamic corrosive system is used in combination with other classical techniques namely, linear polarization, EIS, and hydrogen evolution to track the corrosion pattern of the alloy in SBF for 24 h. The electrochemical results reveal a steady increase in the corrosion resistance of the alloy with immersion time reaching 1398 ohm cm2 at 24 h. This corroborates the hydrogen evolution results in which a declining trend in the corrosion rate with immersion time is observed. The corrosion rate of the alloy is in the range of 1.326-1.338 mm y-1 at 24 h. The results from the applied techniques are comparable. The surface analysis (scanning electron microscope, energy-dispersive x-ray spectroscopy, atomic force microscopy AFM) results conform with the results obtained from applied methods.
