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Öğe Beton karışım suyu ve boşluk suyuna katılan ekolojik inhibitörlerin donatı korozyonuna etkisinin araştırılması(Düzce Üniversitesi, 2020) Kurtay, Mine; Gerengi, HüsnüKorozyon, betonarme yapıların en büyük sorunudur. Korozyonu önlemek için çimentoya organik ve inorganik inhibitörler eklenir. Günümüzde bazı inorganik ve organik bileşiklerin toksisitesi nedeniyle, doğal inhibitörlerin kullanımına daha fazla dikkat edilmektedir. Bu çalışmanın amacı; 2 saat, 7, 28, 56 ve 90 gün süreyle beton karışım suyu ve beton boşluk suyuna maruz kalan donatı çeliklerinin korozyon mekanizmasını araştırmaktır. Karışım suyu ve boşluk suyu çözeltilerindeki donatıların korozyon direnci; Dinamik Elektrokimyasal Empedans Spektroskopisi (DEIS), Elektrokimyasal Empedans Spektroskopisi (EIS) ve Tafel Ekstrapolasyon (TP) yöntemleri kullanılarak belirlenmiştir. Ayrıca belirtilen ortam ve koşullara maruz bırakılan donatıların korozyon direncini arttırmak amacıyla ekolojik inhibitörler (50 ppm kafein ve 50 ppm L-arjinin) kullanılmıştır. Elektrokimyasal deneyler sonrası metal yüzeyinde meydana gelen değişimler Taramalı Elektron Mikroskobu (SEM), Enerji Dağılımlı X-Ray Spektroskopisi (EDS), Atomik Kuvvet Mikroskobu (AFM) ve Optik Profilometre (OP) analizleri ile incelenmiş, uygulanan tüm yöntemlerle aralarındaki korelasyon ortaya konulmuştur. Bunlara ek olarak referans ve inhibitör ikameli çimentolar için TS-EN 196-1'e göre 2, 7, 28 günlük standart çimento deneyleri yapılarak basınç dayanımları tespit edilmiştir. Kritik süre olan 28. gündeki numunelerin hidratasyon gelişiminde meydana gelen değişimler SEM, Diferansiyel Termal Analizi (DTA), Termogravimetrik Analiz (TGA), X-Işını Difraksiyonu (XRD) ve Fourier Dönüşümlü Kızılötesi Spektrometresi (FT-IR) analiz teknikleri kullanılarak incelenmiştir. Elde edilen sonuçlara göre, donatı çeliğinin çözeltide bekleme süresi arttıkça korozyon direncinin de arttığı gözlenmiştir. Ayrıca donatı çeliğinin boşluk suyu çözeltisindeki korozyon direncinin karışım suyundan daha iyi olduğu belirlenmiştir. Bekleme süresiyle paralel olarak kullanılan inhibitörlerin donatının korozyon direncini arttırıcı yönde etki ettiği ve L-arjininin kafeine göre daha yüksek inhibisyon etkisi gösterdiği tespit edilmiştir. 75 ppm kafein ve L-arjinin içeren harçların basınç dayanımı 28. günde tüm çimento harçlarından daha yüksek dayanım göstermiştir. Kullanılan her iki inhibitörün de çimento hidratasyonuna katkı sağladığı ve korozyon inhibitörü olarak boşluk suyu ve karışım suyu ortamlarında kullanılabileceği bu tez çalışması ile bilimsel olarak ispatlanmıştır.Öğe 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, MineThe 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.Öğe Corrosion behavior of concrete produced with diatomite and zeolite exposed to chlorides(Techno-Press, 2017) Gerengi, Hüsnü; Koçak, Yılmaz; Jazdzewska, Agata; Kurtay, MineChloride 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.Öğe Corrosion inhibition of reinforcement steel in mixture water by caffeine and L-arginine(Taylor & Francis Ltd, 2021) Kurtay, Mine; Gerengi, Husnu; Chidiebere, Arinzechukwu; Yildiz, MesutMany additives are preferred to extend the usage of concrete constructions in order to increase durability. These compounds have to be non-poisonous and have no undesirable consequences on the environs. Out of all these concerns, amino acids are mainly used in food and drug industries as well as safe corrosion inhibitors in a number of acid solutions. Here, the corrosion inhibition efficacy of optimum concentration (50 ppm) of caffeine and L-arginine has been investigated for reinforcement steel in mixture water (MW) environment. This was performed for a duration of 2 h, 7, 28, 56 and 90 d using electrochemical impedance spectroscopy (EIS), dynamic EIS (DEIS), and potentiodynamic polarization (PDP) techniques. The surface of specimens was also investigated by atomic force microscopy (AFM), optical profilometer (OP) and scanning electron microscopy (SEM). DEIS results indicate that selected inhibitors protected reinforcement steel approximately up to 62% against corrosion till 7 d, then the effectiveness of the protection decreased to 30% on 90th day. It was also observed that L-arginine showed better inhibition efficiency than caffeine.Öğe The effect of caffeine molecule on the physico-chemical properties of blended cement(Elsevier Sci Ltd, 2020) Kurtay, Mine; Gerengi, Husnu; Kocak, YilmazCaffeine is a nontoxic and eco-friendly natural molecule used in the food industry as well as a corrosion inhibitor in various corrosive media. However, its behavior and performance as an additive in the construction industry has not been explored. This paper investigates the effect of caffeine as an additive on strength, water demands, setting time and hydration mechanism of cement. In the first instance, the water demand, volume expansion and setting time of cement pastes, incorporating 0, 25, 50 and 75 ppm of caffeine were determined. In the second section, the rate of hydration and cement pastes' products were conducted by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermal analysis and scanning electron microscope (SEM) at 28 days. Finally, the cement mortars' compressive strengths were determined at 2, 7 and 28 days intervals. Consequently, mortars containing 75 ppm caffeine registered higher strength than the pure cement mortars due to high quantities of primary C-S-H gel, chemically bound water, compact structure at 28 days. Furthermore, by result of analysis and experiments, it was determined that caffeine had no negative effect on cement. (C) 2020 Elsevier Ltd. All rights reserved.Öğe 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, HaticeThe 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/).Öğe 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, MineIt 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.Öğe 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, ErtuğrulThe 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.Öğe 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, HaticeCorrosion 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.Öğe Impact of Copper Chrome Boron (CCB) Wood Preservative on the Corrosion of St37 Steel(Amer Chemical Soc, 2014) Gerengi, Hüsnü; Taşçıoğlu, Cihat; Akçay, Çağlar; Kurtay, MineCopper chrome boron (CCB) is a well-known new-generation wood preservative. In this study, the corrosion inhibition performance of CCB on St37 steel in 3.5% (w/v) NaCl was examined using dynamic electrochemical impedance spectroscopy (DEIS), potentiodynamic polarization, and scanning electron microscopy. Results of corrosion tests on the system under investigation revealed that CCB displayed inhibitor properties, behaving predominantly as a slightly anodic inhibitor. Scientifically, this work can contribute to an understanding of the mechanism of corrosion of St37 steel fasteners used with CCB-treated and untreated wood.Öğe İnşaat sektöründe kullanılan alüminyum alaşımlarında asit yağmurlarının etkisiyle oluşan korozyonun incelenmesi(Düzce Üniversitesi, 2014) Kurtay, Mine; Gerengi, HüsnüKorozyon kavramı, metal ve alaşımlarının çevreleri ile kimyasal ve elektrokimyasal reaksiyonları sonucu bozulmalarını tanımlamak için kullanılır. Alüminyum, oksidasyona karşı üstün direnci ile tanınır. Bu direncin temelinde pasivasyon özelliği yatar. Endüstrinin pek çok kolunda milyonlarca farklı ürünün yapımında alüminyum kullanılmaktadır. Özellikle, alüminyumdan üretilmiş yapısal bileşenler hafiflik ve yüksek dayanım özellikleri gerektiren taşımacılık ve inşaat sanayinde geniş kullanım alanı bulur. Yapı cephesini tümüyle saran, giydiren ve alüminyum doğrama profilleri kullanılarak oluşturulan konstrüksiyona, alüminyum giydirme cephe adı verilmektedir. Alüminyum giydirme cephe sistemleri; hafifliği ile yapıya az yük binmesini sağlayan özellikleri ile inşaat sektöründe kullanımı her geçen gün artan bir uygulamadır. Ancak, sanayi ve ulaşım araçlarının yoğun olarak geçtiği bölgelerde hava kalitesinde meydana gelen değişiklikler nedeniyle bu yapıların korozyona uğradığı bilinmektedir. Bu çalışma ile yapay asit yağmuruna maruz kalan alüminyum dış cephe giydirme sistemlerinde kullanılan 6060 ve 6082 alüminyum alaşımlarında meydana gelen korozyon, korozyon ölçüm metotlarından Tafel polarizasyon (TP), Lineer Polarizasyon (LP), Elektrokimyasal Empedans Spektroskopisi (EIS) ve daha önce böyle bir sistemde hiç uygulaması olmayan Dinamik Elektrokimyasal Empedans Spektroskopisi (DEIS) yöntemleri kullanılarak belirlenmiş, yöntemlere bağlı elde edilen sonuçlar mukayese edilerek tartışılmıştır. Deney sonuçları SEM ve AFM analizleriyle desteklenmiştir. Deney sonuçları, yapay asit yağmuru çözeltisinde AA6060 metalinin korozyon dayanıklılığının AA6082 metaline göre daha fazla olduğunu göstermektedir. Anahtar sözcükler: Alüminyum, Korozyon, Yapay Asit YağmuruÖğe 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 Kalıp Şartlandırıcı Serpantinde Oluşan Korozyonun İnhibitör Kullanımıyla Engellenmesi(2021) Sarıoğlu, İbrahim; Kurtay, Mine; Yıldız, Mesut; Gerengi, Hüsnü; Ketrez, MustafaPlastik enjeksiyon üretiminde üretilen ürünün, kalıptan soğutularak çıkarılması için su kullanılmaktadır. Zamanla kullanıma bağlı olarak ısınan suyun sıcaklığını istenilen derecede tutmak için chiller cihazları kullanılmaktadır. Enjeksiyon makinelerinde ısınan su, chiller cihazlarında bulunan bakır serpantin (eşanjör) yardımıyla soğutularak tekrar kullanıma hazır hale getirilmektedir. Bu çalışmada; bakır serpantinin korozyonu yapay soğutma suyu (SCW) ve yapay soğutma suyuna katılan 1000 ppm NaNO2 ortamlarında 21 gün süreyle sürekli su devir daimi yapılarak araştırılmıştır. Deney öncesi ve sonrası bakır serpantinin yüzeyi Taramalı Elektron Mikroskobu (SEM), Enerji Dağılımlı X-Ray Kırınımı (EDS) ve Atomik Kuvvet Mikroskobu (AFM) yöntemleri ile incelenmiştir. Korozyon inhibitörü olarak kullanılan NaNO2 bileşiğinin, bakır serpantin üzerinde bir koruyucu film oluşturarak korozyona karşı koruduğu belirlenmiştir.Öğe A morphological and electrochemical comparison of the corrosion process of aluminum alloys under simulated acid rain conditions(Elsevier, 2016) Gerengi, Hüsnü; Bereket, Gözen; Kurtay, MineThe corrosion behavior of aluminum 6060 and 6082 alloys was examined by scanning electron microscopy (SEM), atomic force microscopy (AFM) and dynamic electrochemical impedance spectroscopy (DEIS) after exposure to simulated acid rain for 1, 5, 24 and 48 h. The electrochemical parameters obtained from DEIS were compared with the AFM and SEM studies. Results showed that DEIS is a sensitive technique detecting even very moderate changes in charge -transfer resistance (R-ct); it exhibits a very good correlation with surface morphological changes in relation to exposure time. This research also demonstrated the importance of performing corrosion measurements after a longer time period. (C) 2015 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.Öğe The potency of zeolite and diatomite on the corrosive destruction of reinforcing steel in 1 M HNO3 environment(Elsevier Sci Ltd, 2020) Kurtay, Mine; Gerengi, Husnu; Kocak, Yilmaz; Chidiebere, Maduabuchi A.; Yildiz, MesutConsidering the high neutralizing power of concrete, it is seen as the major material for preserving reinforcing steel. This is observed in reinforced concrete (RC) formation. It is obvious that under corrosive situations, concrete is subject to noticeable quality losses. The aim of this research is to conduct an inquiry on the disintegration of reinforcing steel subjected to 1 M HNO3 solution over 200 days. For this purpose, concrete samples were produced having three different formulations, which included the reference (pure Portland cement), 20% diatomite and 20% zeolite. Reinforcing steel was embedded into these concrete samples. Afterwards, the electrochemical impedance spectroscopy (EIS) approach was used to monitor the system every seven days. The results clearly revealed that long-term experiments are required for accurate electrochemical measurements. The addition of diatomite and zeolite protected the reinforcement better against corrosion. Although it loses its effectiveness over time, zeolite provided better resistance against corrosion than diatomite for the reinforcement bars in 1 M HNO3 solution. (C) 2019 Elsevier Ltd. All rights reserved.Öğe Synergistic corrosion inhibition effect of 1-ethyl-1-methylpyrrolidinium tetrafluoroborate and iodide ions for low carbon steel in HCl solution(Taylor & Francis Ltd, 2016) Gerengi, Hüsnü; Uğraş, Halil İbrahim; Solomon, Moses M.; Umoren, Saviour A.; Kurtay, Mine; Atar, NecipInvestigation into the corrosion inhibition of low carbon steel in 0.1-M HCl solution by 1-ethyl-1-methylpyrrolidinium (EMTFB) and the effect of KI addition on the inhibition efficiency was carried out using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy and surface analysis (scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDAX)) techniques. Results show that EMTFB suppresses low carbon steel dissolution in the corrosive environment. Inhibition efficiency increased with the increase in EMTFB concentration. Addition of iodide ions to EMTFB raises inhibition efficiency from 75 to 98%. PDP results indicate that EMTFB affects majorly anodic reactions while EMTFB + KI act as cathodic-type inhibitor. The adsorption of EMTFB onto low carbon steel surface is by physical adsorption mechanism and follows Langmuir adsorption isotherm model. SEM and EDAX results confirm the adsorption of EMTFB alone and in combination with KI onto the steel surface.
