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Shkirskiy, Viacheslav. "Corrosion inhibition of galvanized steel by LDH - inhibitor hybrids : Mechanisms of Inhibitor Release and Corrosion Reactions". Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066216/document.
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Le travail présenté essaie de comprendre les mécanismes de l’action d’un inhibiteur de corrosion présent dans un revêtement hybride sous forme de pigments intercalés dans les hydroxydes double lamellaires (HDL) pour la protection de l’acier galvanisé. Trois étapes clés ont été choisies pour ce travail : (1) l’identification d’un inhibiteur de corrosion hydrosoluble pour l’acier galvanisé avec une compréhension de sa réactivité, (2) la détermination des facteurs et des mécanismes contrôlant la libération de l’inhibiteur à partir d’HDL et (3) la compréhension des mécanismes de protection dans un système modèle avec le revêtement hybride contrôlé par la libération de l’inhibiteur et la réactivité d’inhibiteur. MoO42- a montré la meilleure efficacité d'inhibition comparable à CrO42- dans des solutions alcalines et neutres. L’effet inhibiteur de MoO42- a été associé à la formation d’un film riche en Mo(V). L'effet de cet anion sur la dissolution de l'acier à bas carbone a été également vérifié pour exclure la possibilité d'un effet d'accélération des espèces choisies. Les tests de lixiviation ont montré que la libération de MoO42- à partir d’HDL a été contrôlée par la nature des ions échangés à partir du support par un mécanisme d'échange d'ions à un pH neutre et par la dissolution du cadre de la LDH à un pH alcalin. La présence de seulement Cl- conduit à moins de 40% de libération de MoO42- après 24 h d'immersion alors que les additions des carbonates ont abouti à libération de 100% après 1 h. Les tests d'immersion ont montré léger effet d'inhibition du système de revêtement dans Cl- et une augmentation dans CO32- en accords avec le niveau plus élevé de MoO42- libéréThe current work was dedicated to the investigation of the fundamental mechanisms of the action of a layered double hydroxide (LDH) inhibitor hybrid coated systems for the corrosion protection of galvanized steel. The objective of the work was achieved by the realization of three milestones: (1) the identification of the effective water soluble inhibitor on Zn and steel substrates and the understanding the mechanisms of its action, (2) the revealing the factors and mechanisms controlling the release of the selected inhibitor from Zn2Al/-LDH hosts and (3) the understanding the mechanisms of coated system controlled by inhibitor release and its action. MoO42- showed the best inhibition efficiency comparable to CrO42- in alkaline and neutral solutions. The protective properties of MoO42- were assigned to the fast formation of Mo(V) film. The effect of MoO42- on the dissolution of low carbon steel was also verified to exclude the possible accelerating effect of chosen species. The leaching tests showed that MoO42- release from LDH was controlled by the nature of the exchanged ions from the media by ion-exchange mechanism at neutral pH and by the dissolution of the LDH framework at alkaline pH. The presence of only Cl- resulted in less than 40 % of MoO42- release after 24 hours of the immersion while the additions of the carbonates resulted in 100 % release after 1 hour. The immersion tests showed slight inhibiting effect of coated system in Cl and high in CO32- medias coherent with higher level of MoO¬42- released. The ways to control the inhibitor release and hence, the inhibition performance of coated systems were discussed in the vein of environment composition
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Ahmed, Mohamed. "Inhibition of mild steel corrosion in cooling systems by low- and non-toxic corrosion inhibitors". Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/inhibition-of-mild-steel-corrosion-in-cooling-systems-by-low-and-nontoxic-corrosion-inhibitors(7dc2367d-7352-4ab2-85b1-39b09d6487d8).html.
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The aim of the research in this thesis was to study how environmentally friendly corrosion inhibitors for cooling water systems might be developed and used. Firstly, reduced toxicity inorganic corrosion inhibitors (i.e. nitrite/molybdate) were considered. Secondly, non-toxic inhibitors based on mono and di-basic salts of carboxylic acids were studied systematically as a function of carbon chain length. For nitrite inhibitor alone, a concentration of 7 mM NaNO2 was effective to inhibit carbon steel in chloride media of 10 mM NaCl, while 10 mM nitrite was needed in sulphate media of 3.66 mM Na2SO4. However, it was found possible to significantly reduce the concentration of nitrite by adding molybdate in synergy. This was attributed to the nitrite passivation combined with ferrous molybdate salt film pore plugging thus promoting a continuous and protective film on the material within these media. Thus, in pH 6-10 an inhibition efficiency of 97% was recorded with a mixture of 3 mM nitrite/2 mM molybdate in both chloride and sulphate media and at 25°C and 60°C. However as the solution pH decreased below pH 4 the inhibition efficiency decreased to about 47%.In the second part of the study, the use of sodium salts of carboxylic acids with different chain lengths has been investigated. In this part a summary of the performances and limitations of both mono- and di-sodium carboxylate inhibitors are presented. For mono-carboxylates, the inhibition efficiency reached a maximum value of 95% in stagnant aerated solutions at a chain length of C=4 with a critical inhibition concentration of 6 mM in 10 mM NaCl solution. However the inhibition efficiency gradually decreased as the number of carbon atoms in the chain length increased to more than 8, or less than 4, and this was in agreement with surface hydrophobicity and contact angle results. For lower chain lengths, the carboxylate anion becomes more acidic and complexing of the metal ion while for longer chain lengths, the carboxylate anion becomes less soluble and tends to micellise wherby the active groups are no longer available for surface adsorption. For di-carboxylates the inhibition efficiency improved in 10 mM NaCl at a given chain length compared with mono-carboxylates, and continued to increase to C=8 (sebacate), which achieved excellent inhibition efficiency. However, sebacate is costly so a blend with ethyl hexanoate was found to be economically favoured.
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Petersen, Adam George. "An ultrasound-based test for corrosion inhibitor persistency". Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620324.
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Wang, Hansheng. "Electrochemical investigation of "green" film-forming corrosion inhibitors :". Thesis, KTH, Skolan för kemivetenskap (CHE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-40888.
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In this work, a comparative electrochemical study has been performed to evaluate corrosion inhibition property of several film-forming corrosion inhibitors provide by Akzo Nobel on carbon steel in a chloride solution. For carbon steel exposed to 1 M NaCl solution with and without added inhibitor, electrochemical measurements including electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) at different exposure time intervals, and potentiodynamic polarization at the termination of the exposure, have been performed to investigate the film forming process and to evaluate corrosion inhibition efficiency of the inhibitors, as well as its evolution with time. The corrosion resistance data obtained from the EIS and LPR measurements are in good agreement. The results indicate different inhibition properties of the inhibitors tested. The inhibition effect of SSF CI-1 is negligible in the first hour of exposure, but it increases steadily with time for 1 day, and then remains the same level during the exposure up to one week. SSF CI-2 exhibits a good inhibition effect in the first hour, but the effect decreases with time to a low level after 8 hours, and then increases again with prolonged exposure. SSF CI-4 shows a low inhibition effect during the first day, and then increases to a maximum level after three days’ exposure. For SSF CI-5 and SSF CI-6, the inhibition effect within 8 hours is relative low but higher than that of SSF CI-4, and the effect increases with time during prolonged exposure. The SSF CI-5 seems to be better than SSF CI-6 because of a more stable inhibition effect. The EIS results indicate that most of the inhibitors form a resistive surface film on carbon steel, which becomes more resistive and protective after several days’ of exposure. However, in the initial stage of exposure, the SSF CI-6 does not show an effect of formation of a resistive film on the surface. The potentiodynamic polarization measurements suggest that, SSF CI-1 and SSF CI-2 are anodic type inhibitor, SSF CI-4 is cathodic type inhibitor, and SSF CI-5 and SSF CI-6 are mix type inhibitor. Moreover, the inhibitors tested show a similar corrosion inhibition effect as mussel adhesive protein (MAP) at the low dosage level.
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Heiyantuduwa, Rukshani. "Performance of a penetrating corrosion inhibitor in controlling carbonation induced corrosion in reinforced concrete". Master's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/11581.
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Includes bibliography.Reinforcement corrosion in concrete remains the most serious cause of premature deterioration of concrete structures world-wide, and many methods have been proposed to combat this problem. One method of improving the durability of concrete in aggressive environments is the use of corrosion inhibitors. In this work the effectiveness of an organic penetrating corrosion inhibitor in reducing the rate of corrosion and delaying the onset of corrosion in carbonated concrete is discussed, with reference to corrosion rates.
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Frey, Abigael. "A Mathematical Model of a Corrosion System Containing Inhibitors". University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1525449155620077.
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Yang, Lin. "Corrosion inhibitor system for superprimer coatings on aerospace alloys". Cincinnati, Ohio : University of Cincinnati, 2005. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1135970650.
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Thesis (M.S.)--University of Cincinnati, 2005.Title from electronic thesis title page (viewed Apr. 20, 2006). Includes abstract. Keywords: corrosion-inhibitive paint pigments; aerospace alloys. Includes bibliographical references.
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YANG, LIN. "CORROSION INHIBITOR SYSTEM FOR SUPERPRIMER COATINGS ON AEROSPACE ALLOY". University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1135970650.
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Seong, Jinwook. "Inhibition of Corrosion and Stress Corrosion Cracking of Sensitized AA5083". The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1429701294.
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Zhang, Fan. "The Mussel Adhesive Protein (Mefp-1) : A GREEN Corrosion Inhibitor". Doctoral thesis, KTH, Yt- och korrosionsvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-123489.
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Corrosion of metallic materials is a natural process, and our study shows that even in an alkaline environment severe corrosion may occur on a carbon steel surface. While corrosion cannot be stopped it can be retarded. Many of the traditional anti-corrosion approaches such as the chromate process are effective but hazardous to the environment and human health. Mefp-1, a protein derived from blue mussel byssus, is well known for its extraordinary adhesion and film forming properties. Moreover, it has been reported that Mefp-1 confers a certain corrosion protection for stainless steel. All these facts indicate that this protein may be developed into corrosion inhibitors with ‘green’, ‘effective’ and ‘smart’ properties. In this study, a range of surface-sensitive techniques have been used to investigate adsorption kinetics, film forming and film compaction mechanisms of Mefp-1. In situ atomic force microscopy (AFM) enables the protein adsorption on substrates to be visualized, whereas the ex situ AFM facilitates the characterization of micro- and nano-structures of the protein films. In situ Peak Force AFM can be used to determine nano-mechanical properties of the surface layers. The quartz crystal microbalance with dissipation monitoring (QCM-D) was used to reveal the build-up of the Mefp-1 film on substrates and measure the viscoelastic properties of the adsorbed film. Analytical techniques and theoretical calculations were applied to gain insights into the formation and compaction processes such as oxidation and complexation of pre-formed Mefp-1 films. The electron probe micro analyzer (EPMA) and X-ray photoelectron spectroscopy (XPS) were utilized to obtain the chemical composition of the surface layer. Electrochemical impedance spectroscopy (EIS) measurements were performed to evaluate the corrosion inhibition efficiency of different forms of Mefp-1 on carbon steel substrates. The results demonstrate that Mefp-1 adsorbs on carbon steel surfaces across a broad pH interval, and it forms a continuous film covering the substrate providing a certain extent of corrosion protection. At a higher pH, the adsorption is faster and the formed film is more compact. At neutral pH, results on the iron substrate suggest an initially fast adsorption, with the molecules oriented preferentially parallel to the surface, followed by a structural change within the film leading to molecules extending towards solution. Both oxidation and complexation of the Mefp-1 can lead to the compaction of the protein films. Addition of Fe3+ induces a transition from an extended and soft protein layer to a denser and stiffer one by enhancing the formation of tri-Fe3+/catechol complexes in the surface film, leading to water removal and film compaction. Exposure to a NaIO4 solution results in the cross-linking of Mefp-1, which also results in a significant compaction of the pre-formed protein film. Mefp-1 is an effective corrosion inhibitor for carbon steel when added to an acidic solution, and the inhibition efficiency increases with time. As a film-forming corrosion inhibitor, the pre-formed Mefp-1 film provides a certain level of corrosion protection for short term applications, and the protection efficiency can be significantly enhanced by the film compaction processes. For the long term applications, a thin film composed of Mefp-1 and ceria nanoparticles was developed. The deposited Mefp-1/ceria composite film contains micro-sized aggregates of Mefp-1/Fe3+ complexes and CeO2 particles. The Mefp-1/ceria film may promote the further oxidation of ferrous oxides, and the corrosion resistance increases with time. Moreover, phosphate ions react with Fe ions released from the surface and form deposits preferentially at the surface defect sites. The deposits incorporate into the Mefp-1/ceria composite film and heal the surface defects, which result in a significantly improved corrosion inhibition effect for the Mefp-1/ceria composite film in both initial and prolonged exposure situationsQC 20130610
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Stone, Erica. "EFFECTS OF ORTHOPHOSPHATE CORROSION INHIBITOR IN BLENDED WATER QUALITY ENVIRONMENTS". Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2961.
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This study evaluated the effects of orthophosphate (OP) inhibitor addition on iron, copper, and lead corrosion on coupons exposed to different blends of groundwater, surface water, and desalinated seawater. The effectiveness of OP inhibitor addition on iron, copper, and lead release was analyzed by statistical comparison between OP treated and untreated pilot distribution systems (PDS). Four different doses of OP inhibitor, ranging from zero (control) to 2 mg/L as P, were investigated and non-linear empirical models were developed to predict iron, copper, and lead release from the water quality and OP doses. Surface characterization evaluations were conducted using X-ray Photoelectron Spectroscopy (XPS) analyses for each iron, galvanized steel, copper, and lead/tin coupon tested. Also, a theoretical thermodynamic model was developed and used to validate the controlling solid phases determined by XPS. A comparison of the effects of phosphate-based corrosion inhibitor addition on iron, copper, and lead release from the PDSs exposed to the different blends was also conducted. Three phosphate-based corrosion inhibitors were employed; blended orthophosphate (BOP), orthophosphate (OP), and zinc orthophosphate (ZOP). Non-linear empirical models were developed to predict iron, copper, and lead release from each PDS treated with different doses of inhibitor ranging from zero (control) to 2 mg/L as P. The predictive models were developed using water quality parameters as well as the inhibitor dose. Using these empirical models, simulation of the water quality of different blends with varying alkalinity and pH were used to compare the inhibitors performance for remaining in compliance for iron, copper and lead release. OP inhibitor addition was found to offer limited improvement of iron release for the OP dosages evaluated for the water blends evaluated compared to pH adjustment alone. Empirical models showed increased total phosphorus, pH, and alkalinity reduced iron release while increased silica, chloride, sulfate, and temperature contributed to iron release. Thermodynamic modeling suggested that FePO4 is the controlling solid that forms on iron and galvanized steel surfaces, regardless of blend, when OP inhibitor is added for corrosion control. While FePO4 does not offer much control of the iron release from the cast iron surfaces, it does offer protection of the galvanized steel surfaces reducing zinc release. OP inhibitor addition was found to reduce copper release for the OP dosages evaluated for the water blends evaluated compared to pH adjustment alone. Empirical models showed increases in total phosphorus, silica, and pH reduced copper release while increased alkalinity and chloride contributed to copper release. Thermodynamic modeling suggested that Cu3(PO4)2•2H2O is the controlling solid that forms on copper surfaces, regardless of blend, when OP inhibitor is added for corrosion control. OP inhibitor addition was found to reduce lead release for the OP dosages evaluated for the water blends evaluated compared to pH adjustment alone. Empirical models showed increased total phosphorus and pH reduced lead release while increased alkalinity, chloride, and temperature contributed to lead release. Thermodynamic modeling suggested that hydroxypyromorphite is the controlling solid that forms on lead surfaces, regardless of blend, when OP inhibitor is added for corrosion control. The comparison of phosphate-based inhibitors found increasing pH to reduce iron, copper, and lead metal release, while increasing alkalinity was shown to reduce iron release but increase copper and lead release. The ZOP inhibitor was not predicted by the empirical models to perform as well as BOP and OP at the low dose of 0.5 mg/L as P for iron control, and the OP inhibitor was not predicted to perform as well as BOP and ZOP at the low dose of 0.5 mg/L as P for lead control. The three inhibitors evaluated performed similarly for copper control. Therefore, BOP inhibitor showed the lowest metal release at the low dose of 0.5 mg/L as P for control of iron, copper, and lead corrosion.Ph.D.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engineering PhD
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Canto, Maya Christian M. "Effect of Wall Shear Stress on Corrosion Inhibitor Film Performance". Ohio University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1447954894.
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Hansen, Joan Elizabeth. "A study of polymeric corrosion inhibitors for copper". Case Western Reserve University School of Graduate Studies / OhioLINK, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=case1057601491.
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Leong, Hoi San. "Effect of corrosion inhibitor and laser surface treatment on corrosion behavior of steel used in chilling system". Thesis, University of Macau, 2011. http://umaclib3.umac.mo/record=b2550589.
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Li, Chong. "Effect of Corrosion Inhibitor on Water Wetting and Carbon Dioxide Corrosion in Oil-Water Two-Phase Flow". View abstract, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3371584.
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Winkler, Jonathan M. "Structural performance evaluation of the Postrite post-treatment corrosion inhibitor system". Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-08222008-063213/.
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Ajayi, Fredric. "Mitigating corrosion risks in oil and gas equipment by electrochemical protection : top of the line corrosion". Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/mitigating-corrosion-risks-in-oil-and-gas-equipment-by-electrochemical-protection-top-of-the-line-corrosion(550870a4-9373-4872-a076-a52f48a5a4f2).html.
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This study investigated the corrosion processes at the top and bottom of carbon steel pipelines transporting wet gases, and studied possible chemical mitigation strategies. First, immersion tests were carried out using carbon steel to study the effects of de-aeration with high purity nitrogen gas on the corrosion rate. Secondly, the corrosion rate was assessed for varying chloride ion concentrations in an aerated environment. In general, increasing de-aeration time changes the corrosion mechanism from mass transfer oxygen reduction to water reduction reaction. However, oxygen solubility controlled the corrosion process in aerated solution containing different chloride ion concentrations. A special two-electrode cell was designed for the top of the line corrosion (TLC) electrochemical measurements but a conventional three electrode cell was used for the bottom of the line corrosion (BLC) measurements. The TLC rate increases with temperature, and X-Ray Diffraction (XRD) confirmed the presence of chukanovite {Fe2(CO3)(OH)2}and possibly ferrous carbonate corrosion products at 40oC and 60oC respectively. However, for the BLC, the cementite phase remained on the metal surface after preferential dissolution of the ferrite phase in the carbon steel. Addition of acetic acid (HAc) locally dissolved the initially FeCO3 film formed on the metal surface, causing local corrosion damage. Addition of methyl di ethanol amine (MDEA) as a pH stabiliser reduced TLC and BLC rates due to enhanced stability of FeCO3 at pH 5.7-6.3. When Zn2+ ions were added as ZnCl2, both Fe2O3 and ZnCO3 were formed at reduced corrosion rate. Whenever FeCO3 film was damaged/dissolved by HAc addition of neither pH stabiliser; MDEA nor hydrate preventer; mono ethylene glycol (MEG) could not re-establish a protective film on the metal surface. The following organic inhibitors were investigated as potential mitigators of TLC: 2-mercaptobenzimidazole (2MBI), 2-amino-5-ethyl-1,3,4-thiodiazole (AETDA), 2-phenyl-2-imidazoline (2PI), dicyclohexylamine (DHA), and a commercial inhibitor formulation (CI-A). The inhibition efficiency (IE%) was found to increase in the order CI-A > 2MBI > AETDA > DHA. Their efficiency increases (except DHA) with inhibitor concentrations both at top and bottom of the line. 2MBI and CI-A behaved as mixed inhibitors but AETDA behaved as cathodic inhibitor, all were best fitted to a simple Langmuir adsorption isotherm. However, IE% of DHA decreased at higher inhibitor concentrations. Surprisingly, 2PI inhibitor increased the corrosion rate, and the corrosion rate further increased with increase inhibitor concentrations. Weight loss measurements results of TLC are also presented which showed lower inhibition efficiency for all the inhibitors investigated compared with electrochemical measurements in similar environments. The free energy of adsorption (∆Goads values for 2MBI and AETDA are around -36kJ.mol-1 while for CI-A the value was -15kJ.mol-1 (-7kJ.mol-1 in the presence of HAc). This is evidence for adsorption of 2MBI and AETDA on the metal surface by chemisorption with CI-A by physisorption. XPS analysis confirmed the presence of FeCO3 and FeOOH as corrosion products in the brine solution in the absence and presence of HAc containing different corrosion inhibitors.
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Guan, Xiaotao. "IMPACT OF ZINC ORTHOPHOSPHATE INHIBITOR ON DISTRIBUTION SYSTEM WATER QUALITY". Doctoral diss., University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3294.
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This dissertation consists of four papers concerning impacts of zinc orthophosphate (ZOP) inhibitor on iron, copper and lead release in a changing water quality environment. The mechanism of zinc orthophosphate corrosion inhibition in drinking water municipal and home distribution systems and the role of zinc were investigated. Fourteen pilot distribution systems (PDSs) which were identical and consisted of increments of PVC, lined cast iron, unlined cast iron and galvanized steel pipes were used in this study. Changing quarterly blends of finished ground, surface and desalinated waters were fed into the pilot distribution systems over a one year period. Zinc orthophosphate inhibitor at three different doses was applied to three PDSs. Water quality and iron, copper and lead scale formation was monitored for the one year study duration. The first article describes the effects of zinc orthophosphate (ZOP) corrosion inhibitor on surface characteristics of iron corrosion products in a changing water quality environment. Surface compositions of iron surface scales for iron and galvanized steel coupons incubated in different blended waters in the presence of ZOP inhibitor were investigated using X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM) / Energy Dispersive X-ray Spectroscopy (EDS). Based on surface characterization, predictive equilibrium models were developed to describe the controlling solid phase and mechanism of ZOP inhibition and the role of zinc for iron release. The second article describes the effects of zinc orthophosphate (ZOP) corrosion inhibitor on total iron release in a changing water quality environment. Development of empirical models as a function of water quality and ZOP inhibitor dose for total iron release and mass balances analysis for total zinc and total phosphorus data provided insight into the mechanism of ZOP corrosion inhibition regarding iron release in drinking water distribution systems. The third article describes the effects of zinc orthophosphate (ZOP) corrosion inhibitor on total copper release in a changing water quality environment. Empirical model development was undertaken for prediction of total copper release as a function of water quality and inhibitor dose. Thermodynamic models for dissolved copper based on surface characterization of scale that were generated on copper coupons exposed to ZOP inhibitor were also developed. Surface composition was determined by X-ray Photoelectron Spectroscopy (XPS). The fourth article describes the effects of zinc orthophosphate (ZOP) corrosion inhibitor on total lead release in a changing water quality environment. Surface characterization of lead scale on coupons exposed to ZOP inhibitor by X-ray Photoelectron Spectroscopy (XPS) was utilized to identify scale composition. Development of thermodynamic model for lead release based on surface analysis results provided insight into the mechanism of ZOP inhibition and the role of zinc.Ph.D.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engineering PhD
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Marek, Martin. "Progresivní bednící systém s protikorozní ochrannou funkcí". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409764.
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Corrosion of reinforcement in reinforced concrete is a huge problem. Corrosion of reinforcement has a great effect on the service life of reinforced concrete structures. The subject of this work is to verify the inhibitors properties and their efficiency using physical and electrochemical methods. The aim of this work is the design of formwork panels with corrosion protection. The formwork panels are on different material basis. Corrosion protection is ensured by the use of migration corrosion inhibitors.
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Huynh, Ngoc Huu. "The Inhibition Of Copper Corrosion In Aqueous Environments With Heterocyclic Compounds". Thesis, Queensland University of Technology, 2004. https://eprints.qut.edu.au/15951/1/Ngoc_Huu_Huynh_Thesis.pdf.
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Benzotriazole (BTAH) has been used as a corrosion inhibitor for copper and copper-, based alloys for more than 40 years. It has been successfully employed for the, prevention of both atmospheric corrosion and particularly for the protection of, copper under immersed conditions. Whilst BTAH is an excellent inhibitor in alkaline, solution its efficiency drops off markedly as the pH decreases. It was hypothesized, that a possible way to increase surface adsorption and subsequent better inhibition, over a wide pH range might be through the preparation of derivatives, particularly, carboxybenzotriazoles and alkyl esters of these compounds.
In this work the following techniques: weight loss measurements, potentiodynamic, polarisation, SERS spectroscopy, electrochemical impedance spectroscopy and, coulometry were employed to investigate the inhibition efficiency of 4- and 5-, carboxybenzotriazole and their alkyl ester for copper corrosion. Molecular modelling, was also investigated as a tool for inhibitor design.
Studies on 4- and 5- carboxybenzotriazole (CBT) showed that the inhibition, efficiency for copper corrosion in aerated acidic sulphate solution of each isomer was, pH, concentration and time dependant. At lower pH the 5-isomer is the better, inhibitor and this behaviour continues at higher pH. The anti-tarnishing test showed, that whilst both isomers exhibited these properties, 5-CBT was once again the, superior inhibitor.
It was found that a commercial mixture of the octyl esters of 4- and 5-, carboxybenzotriazole inhibits copper corrosion in sulphate environments open to air., The inhibition efficiency of the ester mixture at the lx10-4 M level (pH - 0) is 98%, which compares very favourably with that for BTAH (- 50%). With respect to other, alkyl esters of 4- and 5-carboxybezotriazole, hexyl, butyl and methyl, it was found, that all of these inlibited copper corrosion in sulphate environments open to air. In, each case the inhibition efficiency is concentration, pH and time dependent. Both, coupon tests and EIS measurements indicate that inhibition efficiency depends on the, length of the alkyl chain. At pH - 0 the inhibition efficiency decreased in the order, octyl >hexyl >butyl >methyl. At higher pH (- 8) the order is reversed. At the 1x104, M level (pH - 0) the inhibition efficiency of each of the alkyl esters is equal to or, better than that for BTAH. At higher pH (- 8) the inhibition efficiency in each case is, reduced in comparison to BTAH. but is still good enough for practical use ( 2 75%)., The inhibitive behaviour of the alkyl esters at low pH can be attributed to, chemisorption through an azole nitrogen of the protonated alkyl esters. The, hydrocarbon chain is also physically adsorbed and the increase in physical adsorption, as the chain is lengthened accounts for the improved inhibition efficiency.
Dry films formed by immersing copper in solutions of alkyl esters of, carboxybenzotriazole also inhibit copper corrosion in both strongly acidic (pH - 0), and near neutral (pH - S) sulphate corrodents. The inhibition efficiency depends on, the solvents used to dissolve the esters, solution temperature and immersion time., Aqueous coating solutions furnish the most protective films. Films formed by, CBTAH-BU, CBTAH-HE and CBTAH-OE are more protective than that formed by, BTAH. The inhibition efficiency of the alkyl ester film increases as the alkyl chain is, made longer.
Molecular modeling showed that the optimum crude binding energy (Eblnd), between each protonated ester molecule and the surface varied linearly with the alkyl, chain length. The resulting linear correlation between IE% and E bind for compounds, that are structurally similar suggested that the crude binding energy of a single, molecule with copper may be used to predict the inhibition performance of other, compounds constituting a series.
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Huynh, Ngoc Huu. "The Inhibition Of Copper Corrosion In Aqueous Environments With Heterocyclic Compounds". Queensland University of Technology, 2004. http://eprints.qut.edu.au/15951/.
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Benzotriazole (BTAH) has been used as a corrosion inhibitor for copper and copper-, based alloys for more than 40 years. It has been successfully employed for the, prevention of both atmospheric corrosion and particularly for the protection of, copper under immersed conditions. Whilst BTAH is an excellent inhibitor in alkaline, solution its efficiency drops off markedly as the pH decreases. It was hypothesized, that a possible way to increase surface adsorption and subsequent better inhibition, over a wide pH range might be through the preparation of derivatives, particularly, carboxybenzotriazoles and alkyl esters of these compounds. In this work the following techniques: weight loss measurements, potentiodynamic, polarisation, SERS spectroscopy, electrochemical impedance spectroscopy and, coulometry were employed to investigate the inhibition efficiency of 4- and 5-, carboxybenzotriazole and their alkyl ester for copper corrosion. Molecular modelling, was also investigated as a tool for inhibitor design. Studies on 4- and 5- carboxybenzotriazole (CBT) showed that the inhibition, efficiency for copper corrosion in aerated acidic sulphate solution of each isomer was, pH, concentration and time dependant. At lower pH the 5-isomer is the better, inhibitor and this behaviour continues at higher pH. The anti-tarnishing test showed, that whilst both isomers exhibited these properties, 5-CBT was once again the, superior inhibitor. It was found that a commercial mixture of the octyl esters of 4- and 5-, carboxybenzotriazole inhibits copper corrosion in sulphate environments open to air., The inhibition efficiency of the ester mixture at the lx10-4 M level (pH - 0) is 98%, which compares very favourably with that for BTAH (- 50%). With respect to other, alkyl esters of 4- and 5-carboxybezotriazole, hexyl, butyl and methyl, it was found, that all of these inlibited copper corrosion in sulphate environments open to air. In, each case the inhibition efficiency is concentration, pH and time dependent. Both, coupon tests and EIS measurements indicate that inhibition efficiency depends on the, length of the alkyl chain. At pH - 0 the inhibition efficiency decreased in the order, octyl >hexyl >butyl >methyl. At higher pH (- 8) the order is reversed. At the 1x104, M level (pH - 0) the inhibition efficiency of each of the alkyl esters is equal to or, better than that for BTAH. At higher pH (- 8) the inhibition efficiency in each case is, reduced in comparison to BTAH. but is still good enough for practical use ( 2 75%)., The inhibitive behaviour of the alkyl esters at low pH can be attributed to, chemisorption through an azole nitrogen of the protonated alkyl esters. The, hydrocarbon chain is also physically adsorbed and the increase in physical adsorption, as the chain is lengthened accounts for the improved inhibition efficiency. Dry films formed by immersing copper in solutions of alkyl esters of, carboxybenzotriazole also inhibit copper corrosion in both strongly acidic (pH - 0), and near neutral (pH - S) sulphate corrodents. The inhibition efficiency depends on, the solvents used to dissolve the esters, solution temperature and immersion time., Aqueous coating solutions furnish the most protective films. Films formed by, CBTAH-BU, CBTAH-HE and CBTAH-OE are more protective than that formed by, BTAH. The inhibition efficiency of the alkyl ester film increases as the alkyl chain is, made longer. Molecular modeling showed that the optimum crude binding energy (Eblnd), between each protonated ester molecule and the surface varied linearly with the alkyl, chain length. The resulting linear correlation between IE% and E bind for compounds, that are structurally similar suggested that the crude binding energy of a single, molecule with copper may be used to predict the inhibition performance of other, compounds constituting a series.
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Griffin, Allian Sophia. "Corrosion in New Construction:Elevated Copper, Effects of Orthophosphate Inhibitors, and Flux Initiated Microbial Growth". Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/76951.
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It is generally acknowledged that a variety of problems affecting aesthetics, health, and corrosivity of potable water can arise during installation of building plumbing systems. These include 'blue water', microbial infestation, and rapid loss of disinfectant residual, among other things. Frequently cited causes of the problems include metallic fines left in the plumbing lines from deburring, cutting and product fabrication; solder flux residuals (water soluble and petroleum based flux); and solvents for CPVC. Mechanistically, some materials such as flux contain high chloride, high ammonia and cause low pH, which can increase the corrosivity of water held in the lines. Indirect effects are also suspected to be important. For example, ammonia from flux and organic carbon from flux or PVC solvents can spur microbial growth, which in turn can reduce pH or otherwise increase corrosivity. Recent work has also demonstrated that problems with lead leaching to water from brass in modern plumbing can actually be worse in PVC/plastic than in copper systems, if certain types of microbes such as nitrifiers proliferate and drop pH. Some of the problems initiated by construction practices can persist indefinitely, causing higher levels of lead and copper in water, or longer term, contributing to failures of the plumbing system.
Blue water from high copper concentrations is a confounding problem that continues to arise in some locales of the United States. One public elementary school in Miami Dade County is experiencing blue water issues as manifested by blue ice cubes and sink staining. In addition to the aesthetic problems, copper levels are above the EPA's Copper Action Level of 1.3 ppm. Bottled water has been substituted for tap water consumption, which has created a financial burden. The pH of the school's water ranges from 7.15 - 7.5 and the school itself is located 1 ½ miles off the main distribution line resulting in a very low chlorine residual of between 0.06 mg/L Cl2 and 0.18 mg/L Cl2. On site water was shipped to Virginia Tech from Miami to be used in this study. Preliminary testing showed that an increase in the pH of the water would decrease copper leaching. Several pH's were tested which revealed that increasing the pH of the water to 8.5 would drop copper below 1.3 mg/L. When these recommendations were implemented at the school, the high alkalinity and calcium rich water caused calcite scales to form which clogged the chemical feed nozzles. Further bench scale testing indicated that adding 2 mg/L orthophosphate corrosion inhibitor would effectively decrease copper to a level that would comply with the EPA's Copper Action Limit.
Orthophosphate corrosion inhibitors are used by utilities to limit lead and copper corrosion from consumer's plumbing. An evaluation comparing the effects of both 100% orthophosphate inhibitor and orthophosphate/polyphosphate inhibitor blends was performed to study the effects they have on galvanic corrosion, metallic corrosion, microbial growth and the decay of chloramine disinfectant. On site water was sent to Virginia Tech from UNC for use in this bench scale study. The results from this study indicated that 100% orthophosphate inhibitor was the most effective corrosion inhibitor at decreasing metallic corrosion.
It has long been known that microbial activity can have significant effects on water quality. This study evaluated nitrifying and heterotrophic bacterial growth in water systems containing copper pipes, a common plumbing product, and flux which is used in soldering copper pipes together in new construction. There are several types of commercially available fluxes which are often used when soldering new pipes together. Flux ingredients vary and can include extremely high concentrations of ammonia, zinc, chloride, tin, copper and TOC. Flux containing high amounts of ammonia can be detrimental to water quality because it can accelerate the occurrence of nitrification, thus creating a cascading set of problems including, but not limited to, pH decrease and copper corrosion. The results from this case study indicated that flushing a pipe system can effectively decrease the high concentrations of flux present in a new construction system; however, high levels of ammonia from flux can create an environment in which nitrifiers may proliferate within the system.
Many water utilities in the United States are switching disinfection type from chlorine to chloramine due to the increased stability, longer residual time, and overall safety benefits of chloramine. Although chloramines have been found to be a desirable means for disinfection, chloramine decay is an issue of great concern because if the chloramine residual decays, it can leave a water system unprotected against microbial infestation. A preliminary examination of this issue was performed in a laboratory setting to evaluate the many components that effect the stability of chloramine decay, including alkalinity, phosphate, temperature, and various pipe materials. The results from this experiment revealed that temperature increase, pH increase, and aged tygon tubing all accelerated the rate of chloramine decay.Master of Science
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Holmér, Camilla. "Study of green film-forming corrosion inhibitor based on mussel adhesive protein". Thesis, KTH, Skolan för kemivetenskap (CHE), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-143553.
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Today there are numerous methods to slow down a corrosion process of metallic materials. However, due to environmental effects and health risk issues, several traditional corrosion inhibitors have to be phased out. Hence, it is of great importance to develop new corrosion inhibitors that are “green”, safe, smart and multifunctional. In this essay, the focus is on mussel adhesive protein (MAP) and its possibility to reduce the rate of the corrosion process. The protein exhibit great adhesive strength and protective properties, allowing it to adhere to a multitude of different surfaces and is therefore of great interest of corrosion science. The protein Mefp-1, derived from the blue mussel´s foot, had been pre-adsorbed on the carbon steel surface and provided good corrosion inhibition in a basic chloride solution for a short exposure time. The protection was further improved with the assist of iron and ceria ions by formation of protein/ions complexes within the surface films and thus enhanced the corrosion protection for longer exposure time. Ceria nanoparticles were used in order to create a multi-layer composite film with an even higher corrosion protection. The results suggest a denser film compared to previous samples and a more uniform surface.
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Chilukuri, Anusha. "Corrosion Inhibition by Inorganic Cationic Inhibitors on the High Strength Aluminum Alloy, 2024-T3". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1343784869.
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Akbar, Abdulmuhsen. "Understanding the interactions between corrosion scales and inhibitor films in flow conditions". Thesis, University of Leeds, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614641.
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A sweet corrosion environment is known as one which contains carbon dioxide. 12.5% of failures in the oil and gas industry are associated with this environment and the corrosion in it. In some engineering applications and under certain conditions, corrosion layers, such as iron carbonate are produced on material surfaces in which they form a diffusion and physical barrier between the carbon steel surface and the environment and hence protect the carbon steel from further corrosion. Additionally, corrosion inhibitors are used to prevent or decrease material degradation as a result of corrosion for carbon steel. The aim of this study is to assess the conditions required to form iron carbonate layers and the nature of these layers on the surface of X65 carbon steel. The erosion-corrosion resistance of the surface covered with the iron carbonate film in inhibited systems is investigated to assess the interactions between the iron carbonate film and the inhibitor film using both the Rotating Cylinder Electrode (RCE) and the Submerged Impingement Jet (SIJ). It was found that 1% NaCI with pH 7 and ferrous ion concentration of 250 ppm sufficient to produce a FeC03 protective film on the surface ofX65 carbon steel. This was proven using optical microscopy, Scanning Electron Microscope (SEM), Focused Ion Beam SEM (FIBSEM), Energy Dispersive X-Ray (EDX) analysis and Fourier Transform Infrared Spectroscopy (FTIR) analysis. Multi Scale (7.1) software was used to assess the supersaturation conditions in the brine. In addition, material damage of as-received X65 was found to reduce when the inhibitor was used in both RCE and SIJ systems as expected. However, the inhibitor was found to be insufficient to reduce the material degradation of pre- scaled X65 using RCE, whereas this damage of the pee-scaled X65 was decreased using SU. The results are related to the current literature and suggested damage mechanisms are discussed.
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Xiong, Yao. "AFM studies of the Metallicity of Single-walled Carbon Nanotubes and Corrosion Inhibitor Adsorption". Ohio University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1307457679.
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Modesto, Marina Gracinda. "Avaliação do molibdato de sódio, tungstato de sódio e um copolímero a base de silano como inibidores de corrosão para o aço carbono ABNT 1005 em meio de NaCI 3,5%". Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-10112008-112012/.
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O objetivo deste trabalho consiste em avaliar o molibdato de sódio (Na2MoO4), o tungstato de sódio (Na2WO4) e um copolímero a base de silano polioxialquileno e polidimetilsiloxano modificado (CPPM) como inibidores de corrosão para o açocarbono ABNT 1005 em meio de NaCl 3,5%. O estudo compreendeu na exposição do metal no meio proposto na ausência e presença de concentrações crescentes das substâncias estudadas. As técnicas utilizadas foram: ensaios de imersão com medida de perda de massa; medida de potencial de corrosão (Ecorr); espectroscopia de impedância eletroquímica (EIE) e curvas de polarização potenciodinâmicas anódicas e catódicas (Cpol). Os resultados dos ensaios de imersão com medida de perda de massa mostraram que a velocidade de corrosão do aço-carbono ABNT 1005 em meio de água do mar é menor que a velocidade de corrosão em meio de NaCl 3,5%. Os valores de potenciais de corrosão mostraram que o Na2MoO4 e Na2WO4 deslocaram os potenciais para valores mais positivos indicando um comportamento de inibidores anódicos. Os parâmetros obtidos pela técnica de EIE mostraram que para o Na2MoO4 o melhor tempo de imersão foi de 6 horas e para o Na2WO4 foi de 12 horas, com eficiências de 70% e 77%, respectivamente. As Cpol confirmaram os resultados de potenciais de corrosão, ou seja, onde tanto o Na2MoO4 quanto o Na2WO4 comportaram-se como inibidores anódicos para o açocarbono ABNT 1005 em meio de NaCl 3,5%. O valor de perda de espessura com a presença de 1x10-2 mol.L-1 de Na2MoO4 com 24 horas de imersão comparado com o valor obtido em NaCl 3,5% sem inibidor forneceu uma eficiência de 82%, enquanto que na presença de Na2WO4, também com 24 horas de imersão e na concentração de 1x10-2 mol.L-1, a eficiência foi de 65%. Os resultados obtidos com o CPPM mostraram que esta substância não age como inibidor de corrosão para o açocarbono ABNT 1005 em meio de NaCl 3,5%.The aim of this study is to evaluate the sodium molybdate (Na2Mo4), sodium tungstate (Na2WO4) and polydimethyl-siloxane modified copolymer (CPPM) as corrosion inhibitors for the carbon steel ABNT 1005 in 3,5% NaCl media. The metal substrate was exposed in the media with absence and presence of increasing concentrations of the investigated substances. The techniques used were: mass loss tests; open circuit potential; potentiodynamic polarization (Cpol) and electrochemical impedance spectroscopy (EIS). For comparative purpose, mass loss testes were carried out in seawater and in 3,5% NaCl. The results showed that carbon steel ABNT 1005 corrosion rate in seawater is lower than the corrosion rate at 3,5% NaCl. The Na2Mo4 and Na2WO4 corrosion potentials showed more positive values than their absence, indicating an anodic inhibitor behavior. The parameters obtained by EIS technique showed that for the Na2MoO4 the best time of immersion was 6 hours and the Na2WO4 was 12 hours, with efficiencies of 70% and 77% respectively. The Cpol results confirmed the anodic behavior as corrosion inhibitors of the Na2MoO4 and Na2WO4 for carbon steel ABNT 1005 in 3,5% NaCl. After 24 hours of immersion in 1,0x10-2 mol.L-1 Na2MoO4 presence, the corrosion inhibition efficiency estimed using Tafel extrapolation was 82%. In the 1x10-2 mol.L-1 Na2WO4 presence after 24 hours of immersion, the efficiency obtained was 65%. The CPPM results showed it not acting as corrosion inhibitor for carbon steel ABNT 1005 in 3.5% NaCl.
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Allison, Crispin. "Flexible liners for corrosion protection of pipelines". Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7388.
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Flexible plastic liners are sometimes installed into new and existing oil and gas pipelines to prevent corrosion of the pipe wall. A practical difficulty of this method is that the plastic liners are permeable to gases, which can collect and form an annular space between the liner and the pipe. If the operating pressure in the pipe decreases then the collected gas can cause the liner to collapse and block the pipe. One method for overcoming this problem is to insert vents at intervals along the liner to allow the gas to escape into the pipe during depressurisation. However, there is concern that this arrangement might lead to excessive corrosion beneath the vent where the pipe wall is exposed. The rate of corrosion is expected to be controlled by the vent size but this principle needs to be confirmed by experiment. The work described in this thesis is aimed at investigating this corrosion by experiment for a range of conditions typical of oil and gas production. A novel crevice corrosion cell was designed, consisting of an X100 carbon steel plate and a sheet of transparent Perspex, separated by a thin gasket. A small hole in the Perspex simulated a liner vent and allowed carbon dioxide to reach the steel surface. Tests were carried out in 3.5% NaCl solutions saturated with carbon dioxide at 1 bar partial pressure. Corrosion rates along the length of the annular space were measured using the Linear Polarisation Resistance (LPR) technique on pairs of insulated X100 electrodes set into the plate. The corrosion rates within the annular space have been shown to be small compared to those in the bulk solution and to diminish rapidly with distance from the vent. Mathematical modelling, based on the transport of carbon dioxide, is described to explain these findings and support the experimental work. The effectiveness of the LinerVentTM, installed over the vent, in a turbulence pipeline was demonstrated. The benefit of applying cathodic protection within the annular space was also demonstrated. The results are discussed in terms of the fundamental corrosion principles and their practical implications
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Alshehri, Abdulrahman. "IMPACT OF CORROSION INHIBITOR BLENDED ORTHOPHOSPHATE ON WATER QUALITY IN WATER DISTRIBUTION SYSTEMS". Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3248.
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The impact of blended orthophosphate (BOP) inhibitor addition on the corrosion of iron, copper, and lead in drinking water distribution systems was studied under changing water quality environment. Release of iron, copper, and lead were monitored at varying inhibitor doses and changing blends of source waters (groundwater, surface water, and desalinated water). Solid corrosion products on pipe surfaces under BOP treatment were evaluated with surface characterization techniques. Performance of the BOP inhibitor was compared to other corrosion control strategies. Iron scales for iron and galvanized steel coupons incubated in different blended waters in the presence of BOP inhibitor were analyzed by X-ray Photoelectron Spectroscopy (XPS) for surface composition. Identified iron corrosion products were ferric oxide (Fe2O3), magnetite (Fe3O4), and hydrated ferric oxide (FeOOH), in addition to ferric phosphate (FePO4) on coupons exposed to BOP inhibitor. Variations of water quality did not significantly affect the distribution of solid iron forms on surface films. Thermodynamic modeling indicated siderite (FeCO3) was the controlling solid phase of iron release. XPS indicated addition of BOP inhibitor produced a solid phosphate film in the iron scale which could inhibit iron release. Impact of BOP, orthophosphate, and pH adjustment on iron release in a distribution system was examined. Iron release was sensitive to water quality variations (alkalinity and chloride) associated with source and blends of finished water. Finished waters with high alkalinity content (between 149 and 164 mg/L as CaCO3) consistently mitigated iron release regardless of inhibitor use. Dissolved iron constituted about 10% of total iron release. Empirical models were developed that related water quality, inhibitor type and dose to iron release. The BOP inhibitor minimized total iron release followed closely by increasing pH (between 7.9 and 8.1), while orthophosphate dose did not affect iron release. Temperature (ranged from 21.2 to 25.3) had limited influence on iron release with BOP treatment. Monitoring copper release showed that dissolved copper was the dominant form in the effluent, at about 88%. BOP inhibitor doses of 0.5 to 2.0 mg/L proved beneficial in controlling copper concentrations to an average of below 0.5 mg/L. Control of copper release improved with increasing BOP dose, despite changes in alkalinity. Elevation of pH by 0.3 unit beyond pHs (between 7.9 and 8.1) resulted in noticeable decrease in copper concentrations of about 30%, but was more sensitive to higher alkalinity (146 to 151 mg/L as CaCO3) than BOP treatment. Developed empirical models confirmed the importance of BOP inhibitor dose, pH increase, and alkalinity content on copper release. Statistical comparison of the corrosion control strategies proved the advantage of BOP inhibitor, at all doses, over pH elevation in controlling copper release. The BOP inhibitor mitigated lead release below action level, and consistently outperformed pH elevation, in all water quality conditions. XPS analysis identified lead dioxide (PbO2), lead oxide (PbO), cerussite (PbCO3), and hydrocerussite (Pb3(CO3)2(OH)2) as the corrosion products in the scale of lead/tin coupons exposed to BOP inhibitor. XPS and Scanning Electron Microscopy (SEM) analysis suggested cerussite or hydrocerussite is the controlling solid phase of lead release. Thermodynamic models for cerussite and hydrocerussite grossly over predicted actual concentrations. Solubility and equilibrium relationships suggested the possibility of a lead orthophosphate solid that would describe the effectiveness of BOP inhibitor, although no lead-phosphate solid was detected by surface analysis. BOP inhibitor appeared to have mitigated lead release by forming a surface film between lead scale and the bulk water.Ph.D.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engineering PhD
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Chokshi, Kunal. "A Study of Inhibitor-Scale Interaction in Carbon dioxide Corrosion of Mild Steel". Ohio University / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1089819131.
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Lu, Donghui. "The influence of inhibitor ions on localized corrosion of Al and Al alloys /". The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488202171196922.
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Chokshi, Kunal K. "A study of inhibitor-scale interaction in carbon dioxide corrosion of mild steel". Ohio : Ohio University, 2004. http://www.ohiolink.edu/etd/view.cgi?ohiou1089819131.
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Ossorio, Dominguez Anile. "Análise comparativa de inibidores de corrosão na água poro e no concreto armado para aço carbono CA-50". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/148761.
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No presente trabalho analisa-se o comportamento do aço de reforço ante à corrosão, com o uso dos inibidores: nitrito de sódio, fosfato de sódio e etalonamina, na água de poros contaminada com cloreto, e no concreto com a finalidade de analisar seus resultados e seus mecanismos diferenciados. Para cumprir este objetivo o presente trabalho divide-se em duas etapas: uma primeira etapa baseada em simular sinteticamente a água de poro de um concreto, cuja solução é KOH 28g/l+NaOH 4g/l. Essa água de poro é simulada em ambiente marinho, cuja solução é KOH 28g/l + NaOH 4g/l+NaCl 35g/l, e a esta solução referência incorporamse os inibidores (20g/l da cada um). Realizaram-se ensaios de espectroscopia de impedância eletroquímica (EIE) (após 3 e 72 horas de imersão) e curvas de polarização (após 72 horas de imersão) com vistas a obter respostas da cinética da corrosão ante a cada solução. Obteve-se o melhor comportamento para a água de poros. No caso da água de poro contaminada por cloretos, o melhor comportamento se obteve para o inibidor nitrito de sódio. Na segunda etapa adotou-se apenas o inibidor nitrito de sódio, pois estatisticamente as eficiências dos três inibidores foram muito similares. Analisou-se o nitrito de sódio em amostras reais de concreto armado contaminado com cloreto de sódio. Para isso se elegeram dois tipos de cimentos (CP IV e CP V) e três relações água-cimento (a/c-0.4, a/c-0.5, a/c- 0.65). Para simular o ambiente marinho, realizaram-se ensaios acelerados de cloretos. Comparam-se métodos de análises simuladas sinteticamente e reais, concluindo-se em ambos meios, embora fossem um solido e outro líquido o inibidor Nitrito de Sódio aumento a sua eficiência com os ciclos de exposição.In this paper it is analyzed the behavior of reinforcing steel against corrosion using inhibitors: sodium nitrate, sodium phosphate and ethanolamine in water contaminated with chlorides pore and concrete, in order to analyzing the results and different mechanisms. To meet the objective of this work, it was divided into two stages, a first stage based on synthetically simulate the pore water of a concrete, through the following solution KOH 28g/l+NaOH 4g/l, this same solution simulated pore water to a marine environment it would be KOH 28g/l + NaOH 4g/l+NaCl 35g/l, it is then incorporated into both reference solutions inhibitors in a proportion, (20g/l de cada um). Assays were performed electrochemical impedance spectroscopy (EIE) (last 3 hours and 72 hours of immersion) and polarization curves (last 72 hours of immersion) in order to obtain responses corrosion kinetics in each solution. the best performance was obtained in the pore water. In the case of water contaminated with chlorides pore, the best performance was obtained in the presence of sodium nitrite inhibitor. In the second step was performed only with the inhibitor sodium nitrate, as statistically efficiencies of the three inhibitors were similar. Sodium nitrate was analyzed in real samples of reinforced concrete contaminated with chlorides of sodium. So they were chosen two types of cement CP- IV and CP-V, cement water three relationships 0.4, a/c-0.5, a/c- 0.65. In this case to simulate the marine environment, accelerated tests were performed chloride. They were compared the methods of analysis, simulated synthetically and simulated in real concrete.
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Tavassoli-Salardini, Fereshteh, of Western Sydney Nepean University i Faculty of Science and Technology. "Inhibition of mild steel corrosion in aqueous media with sodium propionate". THESIS_FST_XXX_TavassoliSalardini_F.xml, 1996. http://handle.uws.edu.au:8081/1959.7/233.
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The potential use of sodium propionate as a corrosion inhibitor for mild steel in aqueous media is investigated using a range of electrochemical and surface analytical techniques. The use of sodium propionate for the inhibition of mild steel corrosion is discussed, and the effective pH range of sodium propionate using various buffers is investigated. The effectiveness of sodium propionate as an inhibitor for mild steel pitting corrosion in the presence of various concentrations of CI- is studied. The effect of some oxidants, IO3-, BrO3-, NO32- on the anodic behaviour of mild steel in deaerated 0.01M carboxylate solutions of acetate, propionate, formate, succinate and salicylate is investigated. The critical temperature for effective inhibition of mild steel corrosion with sodium propionate is established, and the chemical composition of the film formed on mild steel surface in sodium propionate solution is studied using surface sensitive Fourier transform infrared spectroscopy FTIR. The efficiency of sodium propionate is compared to that of conventional inhibitors and a mechanism for the inhibition of mild steel corrosion with sodium propionate is proposed.Doctor of Philosophy (PhD)
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YANG, HAI. "PLASMA TREATMENT OF ORGANIC INHIBITORS FOR CORROSION PROTECTION OF AEROSPACE ALLOYS". University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1058383366.
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Santos, Isis Valença de Sousa. "Filmes de benzotriazol sobre materiais ferrosos: formação, eficiência, resistência, efeito de aditivos e do transporte de massa". Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/46/46132/tde-12022016-123029/.
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Filmes de benzotriazol (BTAH) formados sobre aços carbono e inoxidável 316L foram estudados em meios de ácido sulfúrico, ácido clorídrico e cloreto de sódio a 25°C. Os seguintes aspectos foram considerados: as condições de formação do filme, sua eficiência, sua resistência em meios não contendo o inibidor,a presença de aditivos e o efeito do transporte de massa sobre o mecanismo da reação. Foram empregadas como técnicas: transitórios de potencial de circuito aberto, ensaios gravimétricos, curvas de polarização potenciostáticas e potenciodinâmicas com eletrodo parado e de disco rotativo, cronoamperometria, espectroscopia de impedância eletroquímica, microscopia ótica, microscopia eletrônica de varredura e análise da superfície por dispersão de energia. O BTAH se mostrou inibidor na grande maioria dos meios para os dois materiais estudados. A resistência dos filmes formados não existe ou é parcial quando as superfícies metálicas revestidas com o filme são imersas nos meios estudados sem inibidor. A adição de Cu(II) aumenta a resistência dos filmes, para determinadas relações [BTAH]/[Cu(II)] que estabilizem o intermediário Cu(I). A presença de íons provenientes da dissolução do aço inoxidável 304 em H2SO4 0,50 mol.L-1 contendo BTAH, eleva significativamente a resistência dos filmes formados, quando estes são expostos aos meios sem inibidor. O cloreto de trimetildodecil amônio exerce sinergismo sobre a ação do BTAH como inibidor de corrosão do aço carbono 1010 em meios ácidos. Superfícies de aço carbono previamente reduzidas são mais eficientes na formação de filmes resistentes aos meios sem inibidor. O transporte de massa do BTAH é uma etapa cinética importante no mecanismo de formação do filme sobre aço inoxidável 316L em meio de HCI 2,0 mol.L-1. O BTAH se mostrou inibidor para a corrosão do aço quando revestido pelo \"primer\" da tinta epóxi, quando adicionado à tinta ou quando o filme é formado antes da aplicação do \"primer\".Benzotriazole (BTAH) films formed on carbon steel and 316L stainless steel have been studied in sulfuric and chloridric acids and in sodium choride solutionsat 25°C. Different aspects were considered: the film formation conditions, its efficiency, its resistance, the presence of additives and the effect of mass transport on the reaction mechanism. Open circuit potential measurements, weight loss experiments, potenciostatic and potentiadynamic polarization curves using stationary and rotating disc electrode, chronoamperometry, electrochemical impedance spectroscopy, optical and scanning electron microscopies and energy dispersive surface analysis have been used as techniques. BTAH have shown inhibitive effect over the majority of the systems studied. The film resistance depends on the presence of the inhibitor in the solution but the result is different if the film is formed in solution containing additives as copper (II) ions or cations obtained from 304 SS dissolution in H2SO4 media; in this case the films resist to chloridric acid media without BTAH. Dodecyltrimetilammonium chloride presents synergism on the inhibitive BTAH action forcarbon steel in acid solution. The BTAH mass transport represents an important step on the film formation mechanism. BTAH is also an effective inhibitor for carbon steel covered by epoxy primer when it is added to the primer or when the film is formed on the carbon steel surface from a H2SO4 solution containing BTAH.
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Grari, Olfa. "Amélioration des propriétés physico-chimiques et anticorrosives du revêtement de polypyrrole électrodéposé sur l'acier inoxydable 304". Thesis, Besançon, 2015. http://www.theses.fr/2015BESA2041/document.
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L’objectif de ce travail est d’élaborer par voie électrochimique un film de polypyrrole sur l’acier inoxydable 304 à partir d’un électrolyte support d’acide phosphorique et d’améliorer sa résistance à la corrosion par l’utilisation d’ondes ultrasonores haute fréquence (US) et l’incorporation d’un inhibiteur inorganique (KNO3) et de particules de silice (SiO2). L’inhibiteur inorganique a réduit le potentiel d’oxydation du monomère et a été incorporé dans la chaîne polymérique. Les ultrasons ont favorisé la réaction d’électropolymérisation en augmentant le transport des espèces électroactives vers l’électrode. Ils ont engendré des films plus compacts, présentant une topographie plus fine et plus homogène. Les films composites PPy-SiO2 ont été élaborés par différentes méthodes. Une bonne répartition des particules dans la chaîne polymérique a été obtenue avec la méthode multicouche. Tous les films élaborés : PPy-NO3-, PPy-US et PPy-SiO2 offrent une meilleure protection de l’acier inoxydable contre la corrosion en milieu chloruré que le revêtement PPyThe aim of this work is to electrochemically elaborate polypyrrole films on 304 stainless steel in phosphoric acid solution and improve corrosion resistance by the use of high frequency ultrasound (US), incorporation of inorganic inhibitor (KNO3) and silica (SiO2) particles. The inorganic inhibitor reduced the oxidation potential of pyrrole monomers and was incorporated into polymer matrix. Ultrasound favors electrochemical polymerization reaction by improving mass transfer towards the electrode. It leads to films more compact, presenting a thinner and more homogeneous topography. PPy-SiO2 composite films were prepared by different methods. Good particles distribution within polymer matrix was achieved through multilayered method. All formed films: PPy-NO3-, PPy-US and PPy-SiO2 offer better protection of stainless steel against corrosion in chloride environment than PPy coatings
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Costa, Thiago Santangelo. "Obtenção do copolímero de acrilonitrila e vinil-tetrazol e sua aplicação como inibidor de corrosão para meio ácido". Universidade do Estado do Rio de Janeiro, 2007. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=2803.
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Polímeros heterocíclicos abrangem uma grande variedade de materiais, desde simples polímeros lineares sintetizados a partir de monômeros do tipo heterocíclicos vinílicos até polímeros altamente funcionalizados e reticulados. Neste trabalho realizou-se a modificação química da poliacrilonitrila com a incorporação de grupos tetrazol em diferentes teores (1%, 2,5%, 5% e 10%). Os copolímeros de acrilonitrila e vinil-tetrazol obtidos foram caracterizados por FTIR e o seu comportamento térmico analisado por DSC e TGA. Os polímeros heterocíclicos foram avaliados como inibidores de corrosão para aço-carbono em meio ácido obtendo-se bons resultados e alcançando, em alguns casos, uma eficiência de inibição média superior a 70%Heterocyclic polymers enclose a great variety of materials, since simple linear polymers synthesized from monomers of vinyl heterocyclics to polymers highly functionalized and crosslinked. In this work was carried out the chemical modified of polyacrilonitrile with incorporation of tetrazole groups in different quantities (1%, 2,5%, 5% and 10%). The acrilonitrile and vinyl-tetrazole copolymers were characterized by FTIR and its thermal behavior analyzed by DSC and TGA. The heterocyclic polymers were evaluated as corrosion inhibitor to carbon steel in acidic medium. It was obtained good results and in some cases inhibitor efficient average higher than 70% were reached
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Faustin, Milcard. "Étude de l'effet des alcaloïdes sur la corrosoion de l'acier C38 en milieu acide chlorhydrique 1M : application à Aspidosperma album et Geissospermum laeve (Apocynacées)". Thesis, Antilles-Guyane, 2013. http://www.theses.fr/2013AGUY0578/document.
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Ce travail porte sur l'inhibition de l'acier C38 en milieu acide HC1 1M par les extraits alcaloïdes issus de 2 plantes : aspidosperma album et geissospermum laeve. Biodégradables et respectueux de l'environnement, les alcaloïdes pourraient être utilisés temporairement pour prévenir la corrosion de l'acier C39 avec des taux d'inhibition supérieurs à ceux décrits dans la littérature. Dans la première partie du travail, l'influence de la concentration, du temps d'immersion et de la température sur le processus de corrosion de l'acier C38 en milieu HC1 1M en absence de polarisation et spectroscopie d'impédance électrochimique. Les analyses de surface effectuées par microscopie électronique a balayage montrent la présence d'une couche constituée d'un mélange d'oxyde de fer incorporant les alcaloïdes et qui conduit à la diminution de la vitesse de corrosion. La deuxième partie de ce travail a été consacrée à l'isolement des alcaloïdes des deux extraits afin de déterminer le ou les alcaloïdes responsables de l'activité inhibitrice et ainsi remonter aux mécanismes d’adsorption. Il a été montré que l'alcaloïde majoritaire des extraits est responsable de l'inhibitionThis work is devoted to the corrosion inhibition of C38 steel in 1M HCL acid medium by alkaloids extracts from two plants : aspidosperma album and geissospermum laeve. Biodegradable and environmentally friendly, alkaloids could be used temporarily to prevent the corrosion of C38 steel with inhibition rates higher than those described in the literature. The first part of this work studies the influence of concentration, immersion time and temperature on the corrosion inhibitor by electrochemical measurements : polarization curves and electrochemical impedance spectroscopy. The surface analyses conducted by scanning electron microscopy showed the presence of a layer composed of an iron oxide mixture incorporating alkaloids extracts and which leads to the decrease of the corrosion rate. The second part of this work was devoted to the isolation of alkaloids of two extracts in order to determine the alkaloids responsible of the inhibitory activity and thus to determine the adsorption mechanisms. It was showed that the major alkaloids of two extracts is responsible of the inhibition activity
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Ben, Mansour Hela. "Etude du comportement à la corrosion des armatures tendues dans le béton contaminé par des ions chlorure : Effet anticorrosif d’un inhibiteur à base de phosphates". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI085/document.
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La corrosion dans le béton précontraint est considérée parmi les pathologies les plus dangereuses dans le secteur du génie civil. En effet ce phénomène se caractérise par la gravité de ses conséquences économiques et sécuritaires. L’objectif de ce travail consiste à évaluer l’efficacité d’un inhibiteur à base de phosphates Na3PO4.12H2O contre la corrosion des aciers de précontrainte. L’étude a été d’abord menée en milieu synthétique simulant le béton chloruré sur des armatures tendues à 80% Rm, puis d’une part sur des éprouvettes en mortier précontraint conçues à l’échelle laboratoire, et d’autre part en utilisant la technique de cellule de diffusion pour tester l’efficacité de l’inhibiteur à long terme. Les résultats issus de l’étude réalisée dans le milieu simulant ont révélé que la présence des phosphates entraine l’augmentation du seuil critique d’amorçage de corrosion localisée R=[Cl-]/[OH-] jusqu’à la valeur de 5 au lieu de 0,4. Ceci semble être dû à deux actions inhibitrices des phosphates à savoir : la stabilisation de la couche protectrice à base d’oxyde de fer et la formation de composés phosphatés très peu solubles qui bloquent les sites anodiques actifs, augmentant ainsi la résistance de l’acier à la corrosion localisée. L’emploi de Na3PO4.12H2O en tant qu’adjuvant diminue légèrement la résistance à la compression du mortier. Cependant les composés phosphatés provenant de la réaction de l’inhibiteur avec les hydrates de ciment colmatent les pores du mortier et freinent la diffusion des chlorures. Ceci améliore le comportement à la corrosion des armatures enrobées de mortier précontraint. Enfin, lorsque le triphosphate de sodium est utilisé comme inhibiteur migrateur ou comme moyen de prétraitement des armatures, la technique de la cellule de diffusion a montré son efficacité à long terme, grâce à l’augmentation de la période précédant l’amorçage d’une corrosion localisée, où l’armature est en état passifCorrosion in prestressed concrete is considered among the most dangerous pathologies in the civil engineering sector. Indeed, this phenomenon is characterized by the seriousness of its economic and security consequences. The objective of this work is to evaluate the efficiency of a phosphate based inhibitor Na3PO4.12H2O against the corrosion of prestressing steels. The study was first conducted on wires tensioned at 80% Rm and immersed in simulating concrete pore solution. Then it concerned, on one hand, prestressed mortar specimens designed on a laboratory scale and, on the other hand, the long term efficiency of the inhibitor using diffusion cell technique. The results obtained from the study carried out in the concrete simulating medium revealed that the presence of the phosphates causes the increase in the critical threshold of localized corrosion initiation R = [Cl -] / [OH-] up to the value of 5 instead of 0.4. This seems to be due to two phosphate inhibiting actions, namely: the stabilization of the iron oxide protective layer and the formation of very insoluble phosphate compounds which block the active anodic sites, increasing prestressing steel resistance to localized corrosion. The use of Na3PO4.12H2O as an additive slightly reduces the compressive strength of the mortar. However, phosphate compounds resulting from the reaction of the inhibitor with the cement hydrates clog the pores of the mortar and slow down the diffusion of the chlorides. This improves the corrosion behavior of prestressed mortar reinforcement. Finally, when sodium triphosphate is used as a migratory inhibitor or as a means of steel reinforcement pretreatment, the diffusion cell technique has shown its long-term efficiency, thanks to the increase of the period preceding the initiation of a localized corrosion, where the reinforcement is in a passive state
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Menezes, Richard Joseph. "An experimental study of corrosion inhibitor performance and slug flow characteristics in horizontal multiphase pipelines". Ohio : Ohio University, 1994. http://www.ohiolink.edu/etd/view.cgi?ohiou1178135456.
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Zvandasara, Tendayi. "Influence of hydrodynamics on carbon steel erosion-corrosion and inhibitor efficiency in simulated oilfield brines". Thesis, University of Glasgow, 2010. http://theses.gla.ac.uk/2284/.
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Corrosion within the oil and gas sector is an ongoing concern for operators. The challenging nature of extraction and processing fluids is an unavoidable cause of severe metallic corrosion. With modern emphasis on health, safety and the environment, the case for managing corrosion has become an imperative agenda. Whilst new and more effective methods of mitigation are key, an interim solution is improving the value of current methods. A literature survey carried out within this project has revealed CO2 corrosion as contributing to most corrosion related failures within the industry. The corrosion behaviour in CO2 containing environments is complex partly due to the wide range of prevailing conditions such as temperature, CO2 concentration and flow conditions. For oil and gas transportation pipelines, internal corrosion mitigation can be achieved by the use of chemical inhibitors. Inhibitors have been established to be effective but are by no means a complete solution. Issues such as their effectiveness in high velocity and high shear flow are a main consideration for their function. The hydrodynamic nature of the flowing fluids can affect inhibitor efficiency by either slowing the rate of formation of the inhibitive layer or causing degradation of well-formed inhibitive layers. A combined effect may also be active. The corrosion behaviour of carbon steel in simulated oilfield conditions is investigated in this project with emphasis on conditions of varying velocity, impinging flow and consequently shear stress. Since inhibition is the main mitigation technique for fluid related corrosion, the efficiency of a commercially used inhibitor is, in this case assessed in the abovementioned conditions. To simulate both impingement and flow, a jet impingement apparatus is used in conjunction with a segmented-electrode specimen set up to separately study the erosion-corrosion behaviour of different hydrodynamic zones under the jet. Corrosion rates are measured by gravimetric analysis and results are also evaluated with electrochemistry. Additionally, galvanic interactions between the different hydrodynamic zones have been investigated. Visual and light-optical microscopic examinations are also used to assess variable effects within the zones. Under such conditions, the corrosion rates have been found to be significantly higher in impingement zones. Aerated conditions have shown a significant variation in corrosion behaviour between impingement and non-impingement zones. The results in CO2 saturated brines are consistent but with evidence of different relations between hydrodynamics and the corrosion rate. The inhibitor has been shown to be effective in CO2 saturated brines and significantly influenced by both inhibitor concentration and hydrodynamic conditions. Inhibitor efficiency has also shown a complex dependence on concentration and establishes a need to evaluate optimum inhibitor concentrations before field application. Evaluation of the mass loss results against electrochemistry has shown a large discrepancy between the two methods. This rather surprising result suggests solid-free flow is not entirely free of erosion and synergistic effects. This comprehensive study has not only improved current knowledge on the relation between hydrodynamics and inhibitor efficiency but also indicates a critical need to evaluate suitability of current monitoring methods. Electrochemical methods are increasingly used as a method of choice and while they contribute significant monitoring data, they are observed to be unable, alone, to monitor erosion and synergy. An industry review on their suitability to monitor solid-free flow corrosion is recommended.
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Tinani, Suraj P. "Techniques to Analyze Underdeposit Corrosion". Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1272643724.
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Chevalier, Maxime. "Étude de l'effet des alcaloïdes de deux espèces d'arbres guyanaises (Xylopia) sur la corrosion de l'acier C38 en milieu hydrochlorydrique 1M : études électrochimiques et phytochimiques". Thesis, Antilles, 2015. http://www.theses.fr/2015ANTI0099.
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De nos jours, dans le domaine de l’inhibition de la corrosion, la recherche et le développement de molécules plus environnementales est de plus en plus importante. C’est dans cet optique que le laboratoire L3MA poursuit ses travaux sur la recherche de molécules naturelles capable d’agir en tant qu’inhibiteur de corrosion.Ce travail de thèse porte sur l’inhibition de la corrosion de l’acier C38 en milieu acide HCl 1M par les extraits alcaloïdiques de deux plantes : Xylopia frutescens et Xylopia cayennensis. Ces molécules considérées comme respectueuses de l’environnement peuvent être utilisées en tant qu’inhibiteur de corrosion temporaire de l’acier C38 avec des taux d’inhibition supérieurs à 90%. Pour chaque plante, les travaux sont consacrés premièrement à l’étude de son extrait alcaloïdique total en tant qu’inhibiteur de corrosion à l’aide de techniques telles que les courbes de polarisation et la spectroscopie d’impédance. Dans un second temps, le fractionnement de cet extrait alcaloïdique total et l’isolement de certains composés actifs permettront de déterminer les structures de certains alcaloïdes actifs en tant qu’inhibiteur de corrosion, et d’en comprendre le mode d’action et les types d’adsorptionsToday, the research and development of ecofriendly biosourced inhibitor have gained a great interest. The laboratory L3MA is involved in the research and characterization of alkaloids isolated from plants growing wild in Guyana as corrosion inhibitor.The present work continues to focus on the broadening application of plant extracts for metallic corrosion control and reports on the inhibiting effect of alkaloidic extract from two plants: Xylopia frutescens and Xylopia cayennensis. The molecules used are considered like ecofriendly and can be used as corrosion inhibitor of C38 steel. More than 90% of efficiency was obtained. The same workflow was used for each plant: firstly the study of the total alkaloidic extract with polarization curves and electrochemical impedance spectroscopy. In second time, the alkaloidic extract is chromatographied and the main composants are isolated and identified. These main components are tested as corrosion inhibitor, to determine the mode of action and the adsorptions’ forms. XPS and SEM studies confirmed that the plants alkaloidics extracts and the main composants are strongly adsorbed onto the steel surface
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Al-Asadi, Akram A. "Iron Carbide Development and its Effect on Inhibitor Performance". Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1416422709.
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Aranha, Hernani. "O benzotriazol (BTAH) como inibidor de corrosão do aço inoxidável tipo 304 imerso em banhos de decapagem ácido". Universidade de São Paulo, 1994. http://www.teses.usp.br/teses/disponiveis/46/46132/tde-21122015-145730/.
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O comportamento eletroquímico do aço inoxidável 304 foi estudado em meios de ácido sulfúrico a várias temperaturas, utilizando reagentes de diferentes graus de pureza, na ausência e presença de benzotriazol (BTAH). Foram feitos ensaios gravimétricos, medidas de potencial de circuito aberto e curvas de polarização potenciostática anódicas e catódicas e análise dos produtos de corrosão por espectrometria de emissão atômica. O objetivo deste estudo foi avaliar a performance do BTAH como inibidor em banhos de decapagem industriais de H2SO4. O BTAH mostrou-se um inibidor efetivo para o aço 304 em toda a faixa de concentração de ácido e temperatura estudadas. A eficiência do inibidor- decresce com o aumento de temperatura e da concentração de H2SO4. O filme inibidor obedece à isoterma de Langmuir, tanto a 28,0 °C quanto 70,0°C, e os valores de energia livre de adsorção sugerem adsorção química. As impurezas presentes nos reagentes exercem pouco efeito na eficiência do inibidor. Estudos potenciostáticos mostraram que o BTAH é um inibidor anódico em toda a faixa de potencial e temperatura estudadas. Do ponto de vista tecnológico, os resultados mais importantes são: o BTAH inibe o processo de corrosão do aço, mas não impede a dissolução dos óxidos (carepa); o BTAH não promove dissolução seletiva dos elementos de liga.The electrochemical behaviour of 304 stainless steel in sulfuric acid media containing benzotriazole (BTAH), was studied at different temperatures, using reagents of different purity grades. Weight loss experiments, open circuit potential measurements, anodic and cathodic potentiostatic polarisation curves and corrosion product analysis by atomic emission spectrometry were made. This study had as objective to evaluate the BTAH perfonnance as corrosion inhibitor in H2SO4 pick1ing baths. BTAH showed to be an effective inhibitor for 304 SS on the entire range of acid concentration and at alI studied temperatures . Inhibitor efficiency decreases as the temperature or acid concentration mcrease. The inhibitive film obeys to Langmuir isothenn, at 28,0 °C as well at 70,0 °C, and free energy adsorption values suggest chemical adsorption. The impurities present in the reagents have little effect on the inhibitor efficiency. Potentiostatic studies have shown that BTAH is an anodic inhibitor on the entire range of potential and at alI studied temperatures. The principal result for pickling baths aplication are that BTAR prevents the steel corrosion, but it does not avoid the scale dissolution and it does not promote selective steel dissolution.
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Coimbatore, Dhandayuth Venkatesh. "Cerium chloride inhibition for high strength low alloy steel exposed to sulphide polluted seawater". University of Western Australia. School of Mechanical Engineering, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0134.
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[Truncated abstract] Corrosion of steel structures caused by sulphide is a common engineering problem encountered by many industries, such as the petroleum, chemical processing, mining and mineral processing industries. The control of sulphide corrosion is still a controversial topic among corrosion engineers. There is an absence of guideline for a reliable acceptable limit of sulphide level in service and each processing industry has its own empirical values. Selection of inhibitors in the sulphide environment depends on laboratory testing before its actual application in pipelines and reaction vessels. Many investigators have postulated the corrosion mechanisms due to sulphide based on operating envelopes such as pH, chloride, manganese, hydrogen sulphide, sulphate reducing bacteria levels and inhibitor concentration. It is recommended in the literature that the batch dosing of inhibitor and biocide needs to be evaluated in regards to sulphide reducing bacteria (SRB) level, which may produce sulphide concentrations up to 2000 ppm. Although sulphide scale formation may protect the base metal by providing a physical barrier, the detrimental effects of sulphide are often inevitable, such as stress corrosion cracking, hydrogen embrittlement, etc. Currently, there are many chemicals that are used as inhibitors to prevent corrosion by scavenging the sulphide from the environment. Cerium, a rare-earth element, is not used as inhibitor in the sulphide environment. Also, there are no previous research findings on the effects of compounds of rare-earth metals, such as cerium chloride (CeCl3), in sulphide environment. This research examines the corrosion behaviour of 0.4Mo-0.8Cr steel, a High Strength Low Alloy (HSLA) steel, in sulphide-polluted artificial seawater with the addition of CeCl3 and glutaraldehyde. ... It is postulated that the moderate inhibiting effect of CeCl3 is due to the scavenging effect thereby forming Ce2S3 complex. Further reaction of sulphide with steel resulted in ferrous sulphide, leading to an increased corrosion rate. It is also concluded that the CeCl3 interferes with both anodic and cathodic reactions in deaerated conditions. Addition of glutaraldehyde in the sulphide-polluted seawater was found to decrease the corrosion rate. According to the electrochemical measurements conducted, the concurrent addition of glutaraldehyde and CeCl3 appeared to have an added effect on reducing the corrosion of the steel, as evidenced by the increase of the open circuit potential during the short-term testing. From the weight loss measurements after 60 days, sulphide pollution in deaerated seawater was found to increase corrosion rate. This is attributed to the increase of sulphide activity whereby continual dissolution of steel was encountered. From the weight loss tests, it was found that the addition of CeCl3 and glutaraldehyde reduced the corrosion rate of the steel in the solutions containing 0-10 ppm sulphide. There is no noticeable corrosion rate decrease for the solution containing 100 ppm sulphide. The added effect of CeCl3 and glutaraldehyde to the SRB medium has resulted in lower corrosion rates. Further detailed experimentation is required to elucidate the corrosion reduction mechanism in glutaraldehyde-containing environments.
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Yang, Yuan Feng. "Calcium and magnesium containing anti-corrosion films on mild steel". Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/calcium-and-magnesium-containing-anticorrosion-films-on-mild-steel(34a7b76f-8ba6-49a7-a1fa-d87f52dc230f).html.
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Under normal conditions, cathodically protected mild steel in seawater is protected by a precipitated film of calcium carbonate and magnesium hydroxide, the so-called calcareous film. This study has attempted to investigate the dynamics of calcareous deposit formation during cathodic protection and the composition of calcareous deposits formed under different applied current densities, and also the role played by the initial current density in forming a good quality calcareous deposit. In addition, an under protection situation can occur where current demand values are under estimated, or where structures are approaching the end of their design lives. In these conditions, a calcareous film might well occur but complete protection is probably not possible. These situations have also been studied. At low insufficient current densities where steel corrosion is still occurring, a clear correlation exists between the iron containing corrosion product and the overlaying magnesium hydroxide layer. Such effects have also been investigated using pH titration analysis, where the effect of co-precipitation of the iron and magnesium oxides/hydroxides has been shown. At higher current densities a layered precipitate has been shown to occur consisting of an inner magnesium containing layer and an outer calcium containing layer. At obvious overprotection current densities, the mechanical stresses involved in hydrogen evolution are assumed to give rise to film cracking. To augment and compliment the study on calcareous calcium/magnesium films formed during cathodic protection, a calcium-magnesium containing pigment has also been investigated in aqueous solutions at open circuit as a possible corrosion inhibitor. Another study looked at the same inhibitor in conjunction with a sacrificial zinc anode. Very effective inhibition has been shown with the film containing not only magnesium, calcium and phosphorous but also zinc. In all the investigations electrochemical methods have been used together with various surface analytical techniques.
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Nelson, William Forrester. "An Investigation into the Use of Mussel Adhesive Proteins as Temporary Corrosion Inhibitors for HY80 Steel". University of Dayton / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1417774059.
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Biswas, Avidipto. "CORROSION PROTECTION OF COPPER IN OILY MEDIA: MICROSCOPIC MECHANISMS". Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1364487333.
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