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Adsorption and inhibition effect of benzotriazole on brass-118 and brass-MM55 in artificial seawater
(Maik Nauka/Interperiodica/Springer, 2012) Gerengi, Hüsnü; Bereket, Gözen
Corrosion behaviours of the new type special commercial brass alloys, called 118 and MM55, have been investigated by Tafel Extrapolation (TP) and Linear Polarization (LP) methods in artificial seawater. Inhibition effect of benzotrizole (BTA) of four different concentrations for the corrosion of brass samples was investigated. It was found that BTA was acting as mixed type inhibitor and inhibition efficiency was increasing with the increase of BTA concentration. The change of the degree of surface coverage (theta) as a function of inhibitor concentration (c) shows that BTA follows Langmuir adsorption isotherm. Values of adsorption equilibrium constants (K (ads)) and values of free energies of adsorption (Delta G (ads)) were calculated from adsorption isotherms. Results reveal that chemisorption is the initial step of inhibition processes.
Anticorrosive Properties of Date Palm (Phoenix dactylifera L.) Fruit Juice on 7075 Type Aluminum Alloy in 3.5% NaCl Solution
(Amer Chemical Soc, 2012) Gerengi, Hüsnü
The influence of date palm (Phoenix dactylifera L.) (PDL) fruit juice on 7075 type aluminum (AA7075) alloy in 3.5% NaCl solution was investigated by Tafel extrapolarization and electrochemical impedance spectroscopy. It was found that PDL fruit juice acted as a slightly cathodic inhibitor, and inhibition efficiencies increased with the increase of PDL fruit juice concentration. The adsorption of the inhibitor on the metal surface was found to obey the Temkin adsorption isotherm and has a physisorption mechanism.
Assessment of the corrosion behaviour of untreated and chemically treated pure magnesium in simulated body fluid
(Taylor & Francis Ltd, 2022) Gerengi, Hüsnü; Cabrini, Marina; Solomon, Moses M.; Kaya, Ertuğrul
The corrosion behaviour of pure Mg in simulated body fluid (SBF) and the effect of chemical treatment on the corrosion resistance property were investigated using DEIS (dynamic electrochemical impedance spectroscopy), EIS (electrochemical impedance spectroscopy), PDP (potentiodynamic polarization), SEM (scanning electron microscopy), AFM (atomic force microscope), and pH measurement techniques for 30 h. NaOH or H2O2 were utilized for the chemical treatment. The DEIS was used for the first time in the investigation of Mg corrosion in SBF. Results obtained disclosed that the chemical treatment benefitted the anticorrosion property immensely. Results from both the electrochemical and surface analysis techniques are consistent.
Carboxymethyl Cellulose/Silver Nanoparticles Composite: Synthesis, Characterization and Application as a Benign Corrosion Inhibitor for St37 Steel in 15% H2SO4 Medium
(Amer Chemical Soc, 2017) Solomon, Moses M.; Gerengi, Hüsnü; Umoren, Saviour A.
This study has been designed to boost the inhibition efficiency and stability of carboxymethyl cellulose (CMC) and this objective has been achieved by incorporating silver nanoparticles (AgNPs) generated in situ by reduction of AgNO3 using natural honey into CMC matrix. Characterization of CMC/AgNPs composite was done using transmission electron microscope (TEM), Fourier transform infrared (FTIR) spectroscopy, ultraviolet visible spectroscopy (UV-vis), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS). Weight loss, electrochemical (dynamic electrochemical impedance spectroscopy, electrochemical impedance spectroscopy, and potentiodynamic polarization) supported by surface assessment (SEM, atomic force microscope, and FTIR) techniques are deployed for the anticorrosion studies of CMC/AgNPs on St37 specimen in 15% H2SO4 medium. CMC/AgNPs performs better than CMC. At 25 degrees C, optimum inhibition efficiency of 93.94% is afforded by 1000 ppm of CMC/AgNPs from DEIS method. Inhibition efficiency of 96.37% has been achieved from weight loss method at 60 degrees C. CMC/AgNPs is found to retard both the anodic and cathodic reactions and the adsorption is explained using Langmuir adsorption isotherm. AFM and SEM graphics reveal smoother surface for St37 sample in the acid solution containing inhibitor than inthe solution without the inhibiting agent. FTIR and EDS results show that CMC/AgNPs molecules were adsorbed on the metal surface.
Chemical, Electrochemical, and Surface Morphological Studies of the Corrosion Behavior of the AZ31 Alloy in Simulated Body Fluid: Effect of NaOH and H2O2 Surface Pretreatments on the Corrosion Resistance Property
(Amer Chemical Soc, 2022) Gerengi, Hüsnü; Cabrini, Marina; Solomon, Moses M.; Kaya, Ertuğrul; Gritti, Luca; Yola, Mehmet Lutfi
Magnesium and its alloys have attracted attention for biomedical implant materials in dental and orthopedic applications because of their biodegradability and similar properties to human bones. The very high rate of degradation in the physiological systems is, however, a major setback to their utilization. Chemical modification is one of the approaches adopted to enhance the corrosion resistance property of Mg and its alloys. In this work, NaOH and H2O2 were used as a pretreatment procedure to improve the corrosion resistance of the AZ31 Mg alloy in simulated body fluid (SBF). Advanced techniques such as dynamic electrochemical impedance spectroscopy (dynamic-EIS), atomic force microscopy, and optical profilometry were used in addition to the classical mass loss, hydrogen evolution, EIS, and polarization techniques to study the corrosion resistance property of the alloy in SBF for 30 h. Results obtained show that the surface treatment significantly enhanced the corrosion resistance property of the alloy. From dynamic-EIS at 30 h, the charge transfer resistance of the untreated AZ31 Mg alloy is 432.6 omega cm(2), whereas 822.7 and 2617.3 omega cm(2) are recorded for NaOH-and H2O2-treated surfaces, respectively. H2O2 is a better treatment reagent than NaOH. The mechanism of corrosion of both untreated and treated samples in the studied corrosive medium has been discussed.
A comparative analysis of the corrosion characteristics of electro-galvanized steel coated with epoxy zinc-free and zinc-rich coatings in 5% NaCl
(Taylor & Francis Ltd, 2022) Gerengi, Hüsnü; Solomon, Moses M.; Maraşlı, Muhammed; Kohen, Beni B.
Anchor elements and pad hooks are used to attach large or small parts made of Glass Fiber Reinforced Concrete (GFRC) panels to the main structure of a building. The protection of these metallic parts is important to avoid corrosion. This work aims to compare the protection ability of normal epoxy and zinc-rich coatings (96% Zn) against chloride-induced corrosion of GFRC electrogalvanized pad hooks. The ASTM B117 salt spray test methods supported by SEM and EDAX surface analysis were adopted. The influence of surface treatment on coating thickness and performance was also considered. The results obtained show that the normal epoxy coatings are unsuitable for the studied pad hooks. Corrosion progressed under the coatings. Surface pre-treatment has a significant effect on the thickness of coatings. The average thickness of a two-coats untreated, sandblasted, and wire brushed pad hook zinc-rich coated layer is 39.27 mu m, 117.8 mu m, and 228.2 mu m. The sandblasted pad hooks coated with zinc-rich coatings exhibit high corrosion resistance after the salt spray test. The EDAX results reveal that the surface products on the sandblasted zinc-rich coatings were devoid of the main substrate components, namely Fe, Si, and Mn but consisted of 2.43 wt.% O, 0.53 wt.% Cl, and 96.49 wt.% Zn. The absence of these elements implies no corrosion and effective corrosion prevention by zinc-rich coatings. Visual observation and SEM images corroborate the EDAX results. However, the thickness of the sand-blasted zinc-rich coated surface increased from 117.8 mu m to 306.2 mu m due to the formation of ZnO. Zinc-rich coatings are recommended for the protection of GFRC electrogalvanized hooks and elements.
A comprehensive evaluation of mimosa extract as a corrosion inhibitor on AA6060 alloy in acid rain solution: part I. Electrochemical AC methods
(Taylor & Francis Ltd, 2015) Gerengi, Hüsnü; Jazdzewska, Agata; Kurtay, Mine
The inhibition effect of mimosa extract on the corrosion of AA6060 aluminum alloy in acid rain solution was investigated by electrochemical impedance spectroscopy and dynamic electrochemical impedance spectroscopy (DEIS). All the studied electrochemical parameters showed good corrosion inhibitive characteristics with respect to the aluminum alloy in the tested solution. Inhibitor efficiency increased with the concentration and attained 45% at 2750ppm. The advantage of DEIS as a tool for the investigation of corrosion inhibitor influence was discussed.
Corrosion behavior of concrete produced with diatomite and zeolite exposed to chlorides
(Techno-Press, 2017) Gerengi, Hüsnü; Koçak, Yılmaz; Jazdzewska, Agata; Kurtay, Mine
Chloride induced reinforcement corrosion is widely accepted to be the most frequent mechanism causing premature degradation of reinforced concrete structures. The electrochemical impedance of reinforcing steel in diatomite-and zeolitecontaining concrete exposed to sodium chloride was assessed. Chemical, physical and mineralogical properties of three concrete samples (20% diatomite, 20% zeolite, and a reference containing neither) were correlated with corrosion investigations. The steel -reinforced samples were exposed to 3.5% NaCl solution for 500 days, and measured every 15 days via EIS method. Results indicated that porosity and capillary spaces increase the diffusion rate of water and electrolytes throughout the concrete, making it more susceptible to cracking. Reinforcement in the reference concrete was the most corroded compare to the zeolite and the diatomite samples.
Corrosion characteristics of plasma spray, arc spray, high velocity oxygen fuel, and diamond jet coated 30MnB5 boron alloyed steel in 3.5 wt.% NaCl solution
(Walter De Gruyter Gmbh, 2022) Güney, Bekir; Dilay, Yusuf; Solomon, Moses M.; Gerengi, Hüsnü; Özkan, Adem; Yıldız, Mesut
30MnB5 boron alloyed steel surface is coated using different coating techniques, namely 60(Ni-15Cr-4.4Si-3.5Fe-3.2B 0.7C)-40(WC 12Co) metallic powder plasma spray, Fe-28Cr-5C-1Mn alloy wire arc spray, WC-10Co-4Cr (thick) powder high velocity oxy-fuel (HVOF), and WC-10Co-4Cr (fine) diamond jet HVOF. The microstructure of the crude steel sample consists of ferrite and pearlite matrices and iron carbide structures. The intermediate binders are well bonded to the substrate for all coated surfaces. The arc spray coated surface shows the formation of lamellae. The cross-section of HVOF and diamond jet HVOF coated surfaces indicates the formation of WC, W2C Cr, and W parent matrix carbide structures. The corrosion characteristic of the coated steel has been investigated in 3.5 wt.% NaCl solution using electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDAX) techniques. The results reveal that the steel corroded in the medium despite the coatings. However, the extent of corrosion varies. HVOF coated sample demonstrated the highest corrosion resistance while arc spray coated sample exhibited the least. EDAX mapping reveals that the elements in the coatings corroded in the order of their standard electrode potential (SEP). Higher corrosion resistance of HVOF coated sample is linked to the low SEP of tungsten.
Corrosion response of ultra-high strength steels used for automotive applications
(Iop Publishing Ltd, 2019) Gerengi, Hüsnü; Şen, Nuri; Uygur, İlyas; Solomon, Moses M.
The corrosion resistance properties of two ultra-high strength steels, Docol 1200 and 1400 were studied in 3.5 wt% NaCl solution using chemical and electrochemical techniques supported by surface characterization techniques namely scanning electron microscope (SEM), energy dispersive spectroscopy (EDX), atomic force microscope (AFM), and optical profilometer. The mechanical properties of both Docol 1200 and Docol 1400 uncorroded and corroded were determined by tensile test. Results obtained reveal that the two alloys exhibit similar mechanical properties. Corrosion has effect on the mechanical properties of the alloys. Corrosion studies reveal that both Docol 1200 and 1400 are prone to corrosion in NaCl environment. A corrosion rate of 30.6 mpy and 49.6 mpy was recorded for a Docol 1200 at 25 degrees C and 60 degrees C, respectively. For Docol 1400, the corrosion rate obtained at 25 degrees C and 60 degrees C was 32.7 mpy and 52.4 mpy, respectively. Docol 1200 is adjudged to exhibit superior corrosion resistance property than Docol 1400. The optical profilometric results disclose that Docol 1200 and Docol 1400 suffered pitting corrosion in NaCl solution. Pitting corrosion was more severe with Docol 1400 than 1200.
Corrosion-inhibiting effect of Mimosa extract on brass-MM55 corrosion in 0.5 M H2SO4 acidic media
(Elsevier Science Inc, 2012) Gerengi, Hüsnü; Schaefer, Katarzyna; Şahin, H. İbrahim
Mimosa extract was examined as a corrosion inhibitor for brass-MM55 in 0.5 M H2SO4 by using electrochemical impedance spectroscopy and the polarization technique. The polarization studies showed that Mimosa extracts acted as anodic-type inhibitor. The percentage inhibition efficiency (eta), was found to increase with increase of the inhibitor concentration due to the adsorption of the inhibitor molecules on the metal surface. In addition it was established the adsorption follows Temkin adsorption isotherm. Moreover some thermodynamic data were calculated and discussed. The results showed that Mimosa extract could play significant role as a corrosion inhibitor for brass-MM55 in 0.5 M H2SO4 environment. (C) 2012 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
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, Gözen
The 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.
The Effect of Flamestab (R) NOR 116 on EPDM-based Automotive Sealing Profiles
(Rubber Res Inst Malaysia, 2018) Küçük, Sibel Dikmen; Gerengi, Hüsnü; Güner, Yusuf
Ethylene propylene diene polymethylene (EPDM) rubber is one of the fastest growing synthetic rubbers in the market. It is widely used in many fields due to its easy processing and high resistance against outdoor conditions compared to other rubber types. However like all organic compounds, over time it is degraded under weathering conditions such as radiation, heat, ozone and chemical media, all of which can contribute to loss of bulk properties and reduce its service life. Cracks, discoloration, breakage, or staining can occur on the surface of visible automotive profiles due to the effect of UV light. These phenomena are definitely undesirable. In this study, five different EPDM rubber compounds (control and four different Flamestab (R) NOR 116 concentrations) were produced. The effects of the Flamestab NOR 116 were investigated by mechanical and rheological tests and ageing using the internationally recognised Florida artificial weathering test. The aged surfaces were visually scrutinised and surface morphological changes were examined via scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analyses. The results obtained showed that Flamestab (R) NOR 116 can be used as a UV stabiliser for EPDM rubber applications if it is added in amounts of between 1.25 and 2.0 phr.
The effect of Tinuvin derivatives as an ultraviolet (UV) stabilizer on EPDM rubber
(International University of Sarajevo, 2018) Küçük, Sibel Dikmen; Gerengi, Hüsnü; Güner, Yusuf
Ethylene-propylene-diene monomer (EPDM) is one of the most widely used synthetic rubbers, especially in the automotive industry. Despite its many benefits, the chief weakness of EPDM has been the color change occurring in its products due to ultraviolet (UV) rays. It is recognized that UV energy causes the dissociation of bonds (mostly C-C and C-H) in EPDM materials as well as cracks and color changes on the surface. The aim of this study was to investigate the effect of the Tinuvin derivatives widely used as UV stabilizers in the plastics industry on EPDM rubber. The EPDM rubber plates were prepared by adding Tinuvin-P, Tinuvin-213 and Tinuvin-234 as UV absorbers (UVAs) and Tinuvin-123 as hindered amine light stabilizer (HALS) material at a ratio of 1.0 phr (parts per hundred parts of rubber) to an available EPDM formula. The effects of the Tinuvin derivatives were investigated by the internationally recognized Florida outdoor aging test. The surfaces of the EPDM plates were visually scrutinized and surface morphological changes were examined via scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and Fourier transform infrared (FTIR) spectrometry analyses. The results obtained showed that, unlike in the plastic industry, not all Tinuvin derivatives could be used as UV stabilizers for EPDM products. Of all the tested Tinuvin derivatives, the Tinuvin-123 compound was the most effective, indicating it to be suitable for use as a protective UV stabilizer for EPDM rubber applications. Thus, an important issue such as the UV resistance of sealing profiles made by EPDM rubber has been contributed about the suitability of Tinuvin derivatives. © 2018 Sibel Dikmen Kucuk, Husnu Gerengi, Yusuf Guner.
Effect of Ultraviolet Stabilizers on Rubber-Based Automotive Sealing Profiles
(2018) Küçük, Sibel Dikmen; Gerengi, Hüsnü; Güner, Yusuf
Kapı, cam, kaput ve bagaj gibi aracın görünür ve görünmez birçok bölgesinde kullanılan sızdırmazlık profilleri; sentetik etilen propilen dien monomer (EPDM) kauçuktan üretilmektedir. Etilen, propilen ve doymamış dien moleküllerinin bu kombinasyonu, yüksek mekanik özellikler sergiler ve su geçirmez bir yapı oluşturur. Güneş ışığına maruz kalan görünür bölgede kullanılan sızdırmaz profillerin yüzeyinde, yüksek yoğunluklu ultraviyole (UV) radyasyonun ve güneş ışığının etkisiyle, zamanla renk değişimi, çatlama ve lekelenme gözlemlenebilir. Bu çalışmanın amacı, plastik endüstrisinde yaygın olarak kullanılan UV stabilizatörlerin EPDM kauçuğunun UV dayanımına olan etkisini araştırmaktır. UV stabilizatörleri, polimerde meydana gelen kimyasal bağ kırılımı nedeni ile oluşan serbest radikaller ile tepkimeye girerek veya UV ışımayı absorbe ederek polimeri UV ışınlarına karşı korur. Mevcut EPDM formülasyonuna farklı tip ve farklı oranlarda UV stabilizatörler eklenerek EPDM hamur plakaları oluşturulmuştur. UV stabilizatörlerin EPDM plakaları üzerindeki etkileri; mekanik testler ve yüksek yoğunluklu güneş ışığı, yüksek yoğunluklu UV ile yüksek sıcaklık/nem içeren iklim koşullarına sahip ve uluslararası alanda tanınmış Florida açık hava yaşlanma testi ile ölçülmüştür
The effect of zeolite and diatomite on the corrosion of reinforcement steel in 1 M HCl solution
(Elsevier Science Bv, 2015) Gerengi, Hüsnü; Kurtay, Mine; Durgun, Hatice
The greatest disadvantage of reinforced concrete structures is the corrosion occurring in the reinforcement which, over time, causes a reduction in the reinforcement-concrete adherence and eventual sectional loss. The purpose of this study was to reveal the corrosion mechanism of ribbed reinforcement inside additive-free (reference), 20% zeolite-doped and 20% diatomite-doped concrete samples after exposure to 1 M HCl over 240 days. Electrochemical impedance spectroscopy (EIS) measurements were made every 10 days. Consequently, it was determined that the 20% zeolite-doped concrete samples had higher concrete and reinforcement resistance compared to the 20% diatomite-doped and the reference concrete, i.e. they exhibited less corrosion. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
The Effects of Cryogenic Treatment on the Corrosion of AISI D3 Steel
(Univ Fed Sao Carlos, Dept Engenharia Materials, 2015) Uygur, İlyas; Gerengi, Hüsnü; Arslan, Yusuf; Kurtay, Mine
It is well known that cryogenic treatment is used to improve the mechanical properties of a material. Consequently, the use of cryogenic treatment has grown beyond its successful application on tool steels. In this research, the effects of cryogenic treatment on the corrosion of AISI D3 steel in 3.5% NaCl solution were examined by electrochemical impedance spectroscopy (EIS). The surface structure of the AISI D3 steel was examined by scanning electron microscopy (SEM) after the EIS investigations. Results clearly indicated that the pre-treatment of the steel was responsible for a significant effect on corrosion. The heat treatment process prior to the cryogenic treatment and the tempering process after were shown to decrease corrosion resistance.
Electrochemical and morphological assessments of inhibition level of 8-hydroxylquinoline for AA2024-T4 alloy in 3.5% NaCl solution
(Taylor & Francis Ltd, 2018) Gerengi, Hüsnü; Solomon, Moses M.; Kurtay, Mine; Bereket, Gözen; Gökşen, Kadir; Yıldız, Mesut; Kaya, Ertuğrul
The corrosion inhibition of AA2024-T4 in 3.5% NaCl solution by 8-hydroxylquinoline (8-HQ) was investigated by potentiodynamic polarisation (PDP), electrochemical impedance spectroscopy and dynamic electrochemical impedance spectroscopy. Experimental results were supported with scanning electron microscopy (SEM), atomic force microscopy and Fourier transform-infrared (FTIR) spectroscopy analysis. It was found that 8-HQ molecules adsorbed on the alloy surface and protected it against corrosion. SEM, energy dispersive spectroscopy, and FTIR results confirm the adsorption of 8-HQ molecules on AA2024-T4. The inhibition efficiency of 8-HQ is found to increase with increase in concentration and the highest concentration studied (0.05 M) offered corrosion inhibition efficiency of 84%. PDP results show that 8-HQ acts as mixed type inhibitor in the studied medium.
Electrochemical Evaluation of Sustainable Corrosion Inhibitors via Dynamic Electrochemical Impedance Spectroscopy
(American Chemical Society, 2021) Slepski, P.; Gerengi, Hüsnü; Gece, G.; Kaya, Ertuğrul; Rizvi Marziya; Szoci?ski, M.
Finding suitable measurement methods for the effective management of electrochemical problems is of paramount importance, particularly for improving efficiency in corrosion protection. The need for accurate measurement techniques specific to nonstationary conditions has long been recognized, and promising approaches have emerged. This chapter introduces dynamic electrochemical impedance spectroscopy as a novel advancement in electrochemistry that can be used efficiently in galvanostatic and potentiostatic modes. The review focuses first on an explanation of the method and second on presenting a comprehensive corpus covering available studies that have applied dynamic electrochemical impedance spectroscopy for the purpose of preventing corrosion phenomena.This chapter defines the merits of this novel approach compared with the conventional electrochemical impedance spectroscopy method. © 2021 American Chemical Society. All rights reserved.
Electrochemical investigations on the corrosion behaviour of reinforcing steel in diatomite- and zeolite-containing concrete exposed to sulphuric acid
(Elsevier Sci Ltd, 2013) Gerengi, Hüsnü; Koçak, Yılmaz; Jazdzewska, Agata; Kurtay, Mine; Durgun, Hatice
Corrosion is a major concern for most structural applications. Its detrimental effect significantly reduces the life of metallic components. This paper presents the results of an experimental investigation of corrosion in the steel reinforcement of concrete samples having three different substituents: 20% diatomite, 20% zeolite, and a reference without zeolite or diatomite. All concrete specimens were subjected to a solution of 0.5 M H2SO4 for 160 days, and every 15 days electrochemical impedance spectroscopy (EIS) measurements were performed. The results indicated that porosity plays a very important role in reinforcing concrete. The steel reinforcement in the zeolite was less corroded by the H2SO4 solution than the reference and the diatomite samples. (C) 2013 Elsevier Ltd. All rights reserved.

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