Dissertations / Theses on the topic 'Steel – corrosion'
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1
Nilsson, Oskar. "Radiation induced corrosion of steel." Thesis, KTH, Kärnkemi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-40452.
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The aim of this thesis was to investigate the influence of aqueous radiation induced oxidants on stainless steel. This was done by exposing the steel to both radiation and chemically added oxidants under ambient conditions, i.e. in and near room temperature. When water is exposed to radiation several oxidizing species are formed, including hydrogen peroxide, which have been known to increase the risk for corrosion of other materials. Stainless steel is used in many parts in a nuclear power plant, and the results from this thesis could be useful when elucidating whether the steel is an appropriate material to use for these applications.
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Belland, Eirik. "Alternating Current Corrosion of Carbon Steel." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for materialteknologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16342.
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The objective was to investigate if the established theory concerning corrosion calculations and electrochemical behavior of carbon is valid when steel is exposed to AC in an electrolyte consisting of 3,5 wt% NaCl and distilled water. The experimental work was divided in two main parts. The first part concerned corrosion testing, including weight loss measurements in stagnant conditions in combination with linear polarization resistance experiments. AC-current densities investigated was 0-, 50-, 75-, 100-, 150-, 220- and 500 A/m2. Polarization curves were produced on two weight loss samples, one exposed to 150 A/m2 and the other exposed to 220 A/m2, at the end of the weight loss experiments.From the corrosion testing it was found that the estimated corrosion current densities (icorr) from the weight loss experiments on samples exposed to AC-current densities below 500 A/m2, was in an approximate accordance with the icorr values estimated from LPR. At 500 A/m2 the measured corrosion rates and corresponding corrosion currents were slightly higher than the remainder. The higher corrosion rate measured from the samples exposed to 500 A/m2 is suggested related to a non-faradaic corrosion contribution. The suggested mechanism is a facilitation of grain boundary corrosion at high AC-current densities leading to the loss of grains. This being a non-faradaic corrosion contribution it is not possible to measure with LPR or polarization curves. The constant B [mV] from the Stern-Geary equation was estimated on basis of LPR measurements. The constant displayed a decreasing trend with increasing AC-current densities. This was explained by the lowering of anodic and cathodic tafel slopes with increasing AC-current densities. The polarization resistance (Rp’ - [Ω∙m2]) also showed a decreasing trend with increased AC-current densities. This was explained by the increased current response in the LPR measurements with increasing AC-current densities.The second part was intended to elucidate the effect of AC on electrochemical behavior of the carbon steel through producing polarization curves at different AC-current densities using a rotating electrode experimental setup. Alterations in corrosion current densities, cathodic tafel slopes, limiting current density of oxygen reduction and corrosion potentials on steel without AC and at current densities of 100-, 150-, 220- and 500 A/m2 are investigated during the electrochemical testing.  From the rotating electrode experiments no significant change in corrosion current was found with increasing AC-current densities. The potential range, in which limiting current of oxygen reduction (ilim) appeared, decreased with increasing AC-current densities. This decrease in ilim also affected the corrosion potentials (Ecorr). A decrease in the potential range of ilim leads to a more cathodic Ecorr. A particular observation was found at AC-current densities of 150 A/m2 were the effect of ilim seemed absent. The samples exposed to this AC-current density also attained the most cathodic corrosion potentials at approximately -850mVSCE which was between 200-400mV lower than the samples exposed to the remaining AC-current densities. Cathodic tafel slopes showed a decreasing trend with increasing AC-current density. Anodic rafel slopes were considered absent due to pitting above Ecorr.Pictures of the weight loss samples were captured in the SEM. It was found that the formation of pits occurred on all weight loss samples exposed to AC. On the samples without induced AC no sign of pitting was observed. Hence it was found that the corrosion attacks attained a more local character when AC-current was induced in the steel samples.
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Torstensen, Andreas. "AC corrosion on cathodically protected steel." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for materialteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19590.
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This report deals with the effect of alternating current on cathodically protected steel. AC corrosion has become relevant in the offshore industry due to the introduction of the direct electric heating system (DEH). The principle with DEH is to prevent wax solidification inside pipelines by heating them up with alternating current. This can give rise to AC corrosion.DC current densities, AC current densities and DC potential have been measured for steel samples under cathodic protection with applied AC voltage. Weight loss measurements were done of both steel and sacrificial anode samples after the experiments. There have also been focused on the corrosion kinetics of AlZnIn by plotting polarization curves and potential measurements over time with applied AC current.The weight loss measurements have shown that carbon steel is protected against AC corrosion for AC current densities lower than 1300 A/m^{2}. All steel samples had corrosion rate lower than 0,1 mm/year up to this value. SEM investigation showed that no pitting corrosion occurred at any of the steel surfaces. The corrosion rate of AlZnIn increased with increasing AC current density up to 300 - 500 A/m^{2}. At higher AC current density, the sacrificial anodes became passive which resulted in decreased protection current and corrosion rate. Polarization curves of AlZnIn have also shown large resistance when AC is introduced which is probably due to surface coverings.Study of the surface morphology of AlZnIn have shown that more localized corrosion occurs with increasing AC current. At 500 A/m^{2} pitting corrosion occurred at the whole surface and the pits became deeper with increasing AC. This resulted in decreased efficiency of the sacrificial anode and consequently reduced DC current density and corrosion rate of the sacrificial anode.Potential and current measurements have shown that the galvanic potential of steel and AlZnIn became more electropositive with increasing AC current density. It is believed that this is due to more localized corrosion with increasing AC voltage and consequently lowering of the anode/cathode ratio. This will force the potential to more anodic values. The initial DC current density increased with increasing AC voltage for all samples but the passivation of sacrificial anode resulted in high reduction rate with time. Polarization curves of AlZnIn showed that the corrosion potential decreased and the corrosion current increased when AC was introduced. Within the samples exposed to AC there were no significant difference in corrosion potential and corrosion current. The polarization curves of all samples that were exposed to AC were characterized by high ohmic resistance which was due to hydrogen evolution and formation of corrosion products at the surface.
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Singh, Surya Kumar. "Corrosion studies on prestressing steel wires." Thesis, Imperial College London, 2000. http://hdl.handle.net/10044/1/7773.
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Ostrofsky, David. "Effects of corrosion on steel reinforcement." [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0002258.
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Vuong, J. C. T. "Natural corrosion inhibitors for stainless steel." Thesis, University of Manchester, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539460.
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Garsany, Yannick. "Understanding steel corrosion in oilfield brines." Thesis, University of Southampton, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252197.
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Mohammed, Ali Haval Bashar. "Atmospheric pitting corrosion of stainless steel." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/7073/.
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Atmospheric pitting corrosion of austenitic stainless steels 304L and 316L under droplets of MgCl2 have been studied under conditions of relevance to long-term storage of nuclear waste containers using automated deposition of arrays of droplets. The effect of microstructure on the morphology of atmospheric corrosion pits in 304L stainless steel plate was investigated. The presence of retained delta ferrite was found to influence the morphology of pits. Ferrite bands were preferentially attacked, and pits were found to have layered attack morphology dependent on the rolling direction and plane of the metal surface. Solution annealing of stainless steel resulted in ferrite reduction and formation of faceted pits. Pits can grow with an initial shallow dish, which may propagate via ‘earring’ or small satellite pits. The size and morphology were seen to vary with exposure humidity, chloride deposition density and distance from the droplet edge. Pits propagated readily above chloride densities of ~10-4 µg/cm2, depending on alloy and exposure time. Below this value much smaller pits were observed due to a discontinuous solution layer. The formation of secondary spreading and micro-droplet formation was observed for MgCl2 droplets on stainless steel when pits form close to or at the droplet edge. Small pits developed beneath these micro-droplets at lower humidities. This work provides a basis to make recommendations for long-term storage conditions of intermediate nuclear waste (ILW) in order to minimise the risk of pitting corrosion.
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Bennett, Andrew Richard. "Novel anti-corrosion coatings on steel." Thesis, Swansea University, 2009. https://cronfa.swan.ac.uk/Record/cronfa42310.
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The primary objective of the work detailed in this thesis was to further explore the inhibitory performance of polyaniline for the prevention of corrosion-driven cathodic disbondment on steels and zinc-alloy coated steels. Polyaniline was investigated under atmospheric conditions so as to make possible further elucidation of the mechanisms by which it would provide this inhibition. Accordingly it is suggested that the positive performance of polyaniline indicated within this report, in addition to further mechanistic understanding, paves the way for industrial use of polyaniline as an inhibitor. To provide further mechanistic support to the inhibitory performance of polyaniline, polyaniline micro-films were applied to the metal substrate surfaces, allowing the visualisation of electrochemical and acid-base state changes resulting from substrate contact and corrosion. Due to industrial concerns over the current cost associated with polyaniline inhibitor pigments, the inhibitory properties of novel organic acid etch primers were explored on both iron and zinc substrates. The findings of this study led to the proposition that the presence of polyaniline may not be required within the model organic coating system in order to provide a similar level of inhibition. Alongside the investigations of inhibitory organic coating systems, attention was directed towards novel Mg-Al-Zn metallic coatings. These are shown to provide inhibition of cathodic disbondment of organic coatings where no form of in-coating inhibition is present. These alloy-coated steels were found to suffer from a novel form of corrosion and full mechanistic proposition is provided, as well as important initiation factors. Finally, the photovoltaic possibilities of polyaniline were explored in order to find novel, high value coating systems for the pre-painted steel industry. Accordingly the photovoltaic properties of polyaniline are compared to established photovoltaic polymers.
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Abosrra, L. R. "Corrosion of steel reinforcement in concrete : corrosion of mild steel bars in concrete and its effect on steel-concrete bond strength." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/5417.
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This thesis reports on the research outcome of corrosion mechanism and corrosion rate of mild steel in different environments (saline, alkaline solutions and concrete media) using potentiodynamic polarization technique. The study also included the effect of corrosion on bond strength between reinforcing steel and concrete using pull-out test. Corrosion of mild steel and 316L stainless steel with different surface conditions in 1, 3 and 5% saline (NaCl + Distilled water) was investigated. Specimens ground with 200 and 600 grit silicon carbide grinding paper as well as 1μm surface finish (polished with 1μm diamond paste) were tested. In case of mild steel specimens, reduction in surface roughness caused increase in corrosion rate, while in 316L stainless steel corrosion rate decreased as the surface roughness improved. Metallographic examination of corroded specimens confirmed breakdown of passive region due to pitting corrosion. Corrosion of mild steel was also investigated in alkaline solution (saturated calcium hydroxide, pH =12.5) contaminated with 1, 3 and 5% saline. A series of corrosion experiments were also conducted to examine the efficiency of various concentrations of calcium nitrite (CN) on corrosion behaviour of both as-received and polished mild steel in alkaline solution containing 3% saline after 1 hour and 28 days of exposure. Corrosion rate was higher for the as-received than polished mild steel surface under the same testing conditions in NaCl alkaline solution with and without nitrites due to the effect of surface roughness. Morphology investigation of mild steel specimens in alkaline solution ii containing chlorides and nitrites showed localized pits even at nitrite concentration equal to chloride concentration. Corrosion of steel bars embedded in concrete having compressive strengths of 20, 30 and 46MPa was also investigated. The effect of 2 and 4% CN by weight of cement on corrosion behaviour of steel bar in low and high concrete strengths specimens were also studied. All reinforced concrete specimens were immersed in 3% saline solution for three different periods of 1, 7 and 15 days. In order to accelerate the chemical reactions, an external current of 0.4A was applied. Corrosion rate was measured by retrieving electrochemical information from polarization tests. Pull-out tests of reinforced concrete specimens were then conducted to assess the corroded steel/concrete bond characteristics. Experimental results showed that corrosion rate of steel bars and bond strength were dependent on concrete strength, amount of CN and acceleration corrosion period. As concrete strength increased from 20 to 46MPa, corrosion rate of embedded steel decreased. First day of corrosion acceleration showed a slight increase in steel/concrete bond strength, whereas severe corrosion due to 7 and 15 days corrosion acceleration significantly reduced steel/concrete bond strength. Addition of only 2% CN did not give corrosion protection for steel reinforcement in concrete with 20MPa strength at long time of exposure. However, the combination of good quality concrete and addition of CN appear to be a desirable approach to reduce the effect of chloride induced corrosion of steel reinforcement. At less time of exposure, specimens without CN showed higher bond strength in both concrete mixes than those with CN. After 7 days of corrosion acceleration, the higher concentration of CN gave higher bond strength in both concrete mixes. The same trend was observed at 15 days of corrosion acceleration except for the specimen with 20MPa compressive strength and 2% CN which recorded the highest deterioration in bond strength.
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Lindquist, Lisa. "Corrosion of steel bridge Girder anchor bolts." Thesis, Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24649.
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The research objectives for this project were to explicitly define the anchor bolt corrosion problem in the state of Georgia and recommend action to the Georgia Department of Transportation. The bearing assembly of concern is the plate bearing assembly, in which carbon steel and/or bronze plates are anchored by either carbon steel or stainless steel anchor bolts. Inspection report data revealed that anchor bolt corrosion was ubiquitous for all environments in Georgia; the problem was reported for 27% of the steel girder bridges throughout the state. Based on a synthesis of the field investigations, bolt failure analyses, laboratory experimental testing, and review of GDOT inspection report surveys, the corrosion of carbon steel anchor bolts is caused universally by concentration cell corrosion. Other corrosion mechanisms of concern are galvanic and crevice corrosion, which are both enhanced by the current bearing design.
Corrosion protection provided through zinc galvanization cannot sufficiently protect the carbon steel bolt for its entire service life. Corrosion potential and cyclic polarization data confirmed that ASTM Type 304, Type 316, Type 2101, and Type 2205 were protected from concentration cell and localized corrosion in the simulated bearing environment. Therefore, it is recommended that the stainless steel anchor bolts of these types be use in future designs and that the bolts should be electrically separated from all dissimilar metals using a Nylon or Teflon washer to prevent preferential corrosion of carbon steel. It is further recommended that the bronze lube plate should be eliminated entirely and that the bearing type should be a reinforced elastomeric bearing. Maintenance of existing sliding plate bearings should include regular cleaning by brushing away debris from the bearing surfaces, and bridges with carbon steel anchor bolts should be retrofitted to provide additional lateral restraint according to current maintenance procedures.
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Appleton, Richard Joseph. "Corrosion fatigue of a C-Mn steel." Thesis, University of Glasgow, 1985. http://theses.gla.ac.uk/2176/.
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Walsh, Michael Thomas. "Corrosion of Steel in Submerged Concrete Structures." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/6048.
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This investigation determined that severe corrosion of steel can occur in the submerged portions of reinforced concrete structures in marine environments. Field studies of decommissioned pilings from actual bridges revealed multiple instances of strong corrosion localization, showing appreciable local loss of steel cross-section. Quantitative understanding of the phenomenon and its causes was developed and articulated in the form of a predictive model. The predictive model output was consistent with both the corrosion rate estimates and the extent of corrosion localization observed in the field observations. The most likely explanation for the observed phenomena that emerged from the understanding and modeling is that cathodic reaction rates under oxygen diffusional limitation that are negligible in cases of uniform corrosion can nevertheless support substantial corrosion rates if the corrosion becomes localized. A dynamic evolution form of the model was created based on the proposition that much of the steel in the submerged concrete zone remained in the passive condition given cathodic prevention that resulted from favorable macrocell coupling with regions of the steel that had experienced corrosion first. The model output also matched observations from the field, supporting the plausibility of the proposed scenario.
The modeling also projected that corrosion in the submerged zone could be virtually eliminated via the use of sacrificial anode cathodic protection; the rate of corrosion damage progression in the low elevation zone above water could also be significantly reduced. Continuation work should be conducted to define an alternative to the prevalent limit-state i.e., visible external cracks and spalls, for submerged reinforced concrete structures. Work should also be conducted to determine the possible structural consequences of this form of corrosion and to assess the technical feasibility and cost/benefit aspects of incorporating protective anodes in new pile construction.
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Sidorin, Dmitry. "Studies of steel corrosion in oilfield brines." Thesis, University of Southampton, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438048.
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Mattin, Sarah Patricia. "Nucleation of corrosion pits on stainless steel." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321495.
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Sarveswaran, Velautham. "Remaining capacity of corrosion damaged steel structures." Thesis, University of Bristol, 1996. http://hdl.handle.net/1983/dd074d92-3e3b-4a6c-8bed-ce7dc447307b.
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Salleh, Suhaila. "Modelling pitting corrosion in carbon steel materials." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/modelling-pitting-corrosion-in-carbon-steel-materials(40658bff-f7c5-4675-a7f9-7a5519c6fdd2).html.
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Pitting corrosion is one of the most destructive types of metal loss. The purpose of this study was to investigate the evolution, or in other words, the propagation, of a single pit in carbon steel after the initiation stage. In view of the chemical and electrochemical reactions inside a single pit in carbon steel, a two dimensional model that allows the prediction of pit evolution was developed. Eleven species in aqueous sodium chloride solution and two neutral complexes were considered in the model. Given that the active-passive transition of a metal is a key phenomenon in pitting, the equations used to construct a Pourbaix diagram for iron were incorporated in the model as rules to govern passivation behaviour. By using the finite element package COMSOL Multiphysics as a tool, the Nernst-Planck equations for the mass transport and potential variations were solved. In addition, the multiphysics model was extended with Moving Boundary (ALE) mode to predict shapes of pits. The results of the study were that the model was able to investigate migration of ionic species, account for the active-passive transition of metal and also able to show the effect of solid precipitation. The model was able to show movement of the boundaries of a pit and hence, predict the shapes of pit at a given range of time. The results were discussed in comparison to the Pourbaix diagram of iron and compared with the experimental results and published models reported in literature. The principal conclusion is that modelling corrosion activities with integrated thermodynamic equations based on Pourbaix diagram methods is an outstanding way to model any other corrosion activities.
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Akhoondan, Mersedeh. "Corrosion assessment of mechanically formed aluminized steel." [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0002248.
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James, Liam A. "Graphene layers for corrosion protection of steel." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/235169/1/Liam_James_Thesis.pdf.
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Graphene coatings have previously been used on various metals to prevent corrosion. The corrosion of steels in modern environments is a costly and ongoing issue that may be aided by graphene coatings. This project focused on forming graphene coatings formed on steel samples in a quartz-tube furnace. The coatings were analysed for their quality, and corrosion testing was performed on the coated steel. The graphene coatings were found to have superior corrosion resistance compared to uncoated samples.
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Navabzadeh, Esmaeely Saba. "Galvanic Localized Corrosion of Mild Steel under Iron Sulfide Corrosion Product Layers." Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou151551709542735.
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Miller, Jacob T. "Sulfuric Acid Corrosion to Simulate Microbial Influenced Corrosion on Stainless Steel 316L." Youngstown State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ysu151621775594905.
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Metaferia, Ineku Amhayesus. "Characterization of Steel Corrosion Products in Reinforced Concrete." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42128.
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Steel corrosion is one of the major distress mechanisms that causes the deterioration of reinforced concrete structures around the world. It is an electrochemical reaction between the reinforcing steel and the surrounding concrete that produces a mass loss of the metal. Through the process of corrosion in reinforced concrete, iron ions get oxidized to form corrosion products (CP). Although multiple experiments and studies have been developed to understand the rheological behavior of corrosion products, this topic stays inconclusive. This work aims to characterize corrosion products at micro-scale in order to trace the progress of the formation of rust, to determine its nature and to analyse its rheological behavior in reinforced concrete. An experimental procedure to produce CP in the laboratory is also presented in this research. In addition, material characterization methods have been used to identify the iron oxide phases present in CP, determine their viscosity and rheological behavior and to study how CP flows in a porous media. In order to identify the different stages in the corrosion process, the CP was analysed at 2, 4, 6 and 8 weeks. The experiments identified four phases of iron oxide for each period. Furthermore, it was found that CP behaves as a shear-thinning slurry and as a result, its viscosity decreases with the applied shear rate. In addition, the damage caused by CP on concrete depends on the w/c ratio of the concrete mix and the exposure time to a corroding environment. The rebar mass loss results show that CP is formed in layers around the rebar, and the flow of each CP layer can differ.
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Lou, Xiaoyuan. "Stress corrosion cracking and corrosion of carbon steel in simulated fuel-grade ethanol." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37279.
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Today, ethanol, as well as other biofuels, has been increasingly gaining popularity as a major alternative liquid fuel to replace conventional gasoline for road transportation. One of the key challenges for the future use of bioethanol is to increase its availability in the market via an efficient and economic way. However, one major concern in using the existing gas-pipelines to transport fuel-grade ethanol or blended fuel is the potential corrosion and stress corrosion cracking (SCC) susceptibility of carbon steel pipelines in these environments. Both phenomenological and mechanistic investigations have been carried out in order to address the possible degradation phenomena of X-65 pipeline carbon steel in simulated fuel-grade ethanol (SFGE). Firstly, the susceptibilities of stress corrosion cracking of this steel in SFGE were studied. Ethanol chemistry of SFGE was shown to have great impact on the stress corrosion crack initiation/propagation and the corrosion mode transition. Inclusions in the steel can increase local plastic strain and act as crack initiation sites. Secondly, the anodic behavior of carbon steel electrode was investigated in detail under different ethanol chemistry conditions. General corrosion and pitting susceptibility under unstressed condition were found to be sensitive to the ethanol chemistry. Low tendency to passivate and the sensitivity to ethanol chemistry are the major reasons which drive corrosion process in this system. Oxygen plays a critical role in controlling the passivity of carbon steel in ethanol. Thirdly, the detailed study was carried out to understand the SCC mechanism of carbon steel in SFGE. A film related anodic dissolution process was identified to be a major driving force during the crack propagation. Fourthly, more detailed electrochemical impedance spectroscopy (EIS) studies using phase angle analysis and transmission line simulation reveal a clearer physical picture of the stress corrosion cracking process in this environment. Fifthly, the cathodic reactions of carbon steel in SFGE were also investigated to understand the oxygen and hydrogen reactions. Hydrogen uptake into the pipeline steel and the conditions of the fractures related to hydrogen embrittlement were identified and studied.
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Ghareba, Saad. "Inhibition of carbon steel corrosion by long alkyl-chain amino acid corrosion inhibitors." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104608.
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Carbon steel (CS) is the most commonly used material for equipment and pipes in the oil production processes. However, presence of water/salts and carbon dioxide, among other gases, in the oil is a serious problem due to increased corrosion rate of the material. The most common way of mitigating this problem is by using corrosion inhibitors. However, many common corrosion inhibitors that are in use today are health hazards. Therefore, there is a need to develop more environmentally compatible and biodegradable corrosion inhibitors. Bioorganic and naturally occurring molecules, such as amino acids, are the most obvious candidates. This work was aimed at studying the influence of some amino acids, 11-aminoundecanoic acid (11AA) and 12-aminododecanoic acid (12AA), as corrosion inhibitors for carbon steel (CS) in hydrochloric acid and some other electrolytes that might be used in certain industries.In this study the inhibiting effect of 12AA on corrosion of CS in CO2-free and CO2-saturated 0.5 HCl was investigated as a function of various parameters: inhibitor concentration, electrolyte pH, temperature, treatment time, CS surface roughness, electrolyte flow rate and pattern, effect of electrolyte type. In addition, the interaction of 11AA with the CS surface under selected experimental conditions was also investigated. It was found that 12AA inhibits both partial corrosion reactions, with a slightly stronger inhibition of the anodic corrosion reaction which indicated that 12AA acts as a mixed-type inhibitor. The corrosion protection mechanism is by formation of a surface-adsorbed 12AA monolayer that offers a hydrophobic barrier to transport of solvated corrosive ions to the surface yielding a maximum inhibition efficiency of ~98%. The adsorption of 12AA onto the CS surface was described by the Langmuir adsorption isotherm. The corresponding Gibbs energy of adsorption was calculated to be −26 and −28 kJ mol−1 in the CO2-free and CO2-saturated 0.5 M HCl, respectively. This indicated that the self assembled monolayers (SAM) formation process is spontaneous and reversible. PM-IRRAS measurements revealed that the SAM is amorphous, which could be attributed to the repulsion between the neighboring positively charged amine groups and also to a high heterogeneity of the CS surface. The study showed also that the 12AA can be used as an effective inhibitor of CS general corrosion in several other electrolytes including; acetic acid, perchloric acid and sodium chloride, but its application in nitric and sulfuric acid should be avoided. The corrosion inhibition of the CS surface by 12AA is also effective at higher pH values, although the corresponding corrosion inhibition efficiency decreased due to a decrease in 12AA solubility. 12AA was also confirmed to be an efficient corrosion inhibitor of a CS surface of different roughness.The effect of flow and flow pattern of CO2-saturated HCl on the corrosion inhibition of CS by 12AA was also investigated in a square duct, rotating disk electrode (RDE) and jet impingement cell configuration. 3 mM 12AA provided high corrosion inhibition efficiency in the square duct and RDE configuration. However, in 1 mM 12AA solution, the inhibition efficiency decreased with an increase in Reynolds number (Re), due to desorption of 12AA from the CS surface. 12AA was found to poorly protect CS in the impingement-jet configuration at low Re, while at high Re, acceleration of CS corrosion was recorded.Similar results were also obtained for inhibition of CS corrosion by 11AA. In fact, this molecule was found to better protect CS from corrosion than 12AA. This was attributed to the higher surface coverage of 11AA on the CS surface, i.e. the formation of a more compact 11AA monolayer.L'acier au carbone est le matériel le plus couramment utilisé pour les équipements et les pipelines reliés aux processus de production pétrolière. Toutefois, la présence de certains éléments comme l'eau, les sels and le dioxyde de carbone dans l'huile pose plusieurs problèmes reliés à l'augmentation du taux de corrosion du matériel. La façon la plus répandue d'éliminer ce problème est l'utilisation d'inhibiteurs de corrosion. Il est cependant important de mentionner que la majorité de ces inhibiteurs sont nocifs pour l'être humain. Il est donc nécessaire de développer des composés compatibles avec l'environnement et biodégradables et ceci peut être fait avec l'utilisation d'acides aminés.Ce projet a pour but d'étudier l'influence des acides aminés "11-aminoundecanoic acid" (11AA) et "12-aminododecanoic acid" (12AA) en tant que qu'inhibiteurs pour l'acier carbone dans l'acide chlorhydrique et plusieurs autres électrolytes utilisés dans certaines industries.Dans cette étude, l'effet inhibiteur du 12AA sur la corrosion de l'acier carbone dans une solution sans ou saturée en dioxyde de carbone et avec 0.5 M d'acide chlorhydrique a été étudié. Différents paramètres tels que la concentration des inhibiteurs, la concentration des électrolytes, le pH, la température, le temps de traitement, la rugosité de surface, le taux de flux et les différents types d'électrolytes furent analysés pour mieux comprendre le mécanisme de fonctionnement. De plus, l'interaction du 11AA avec la surface de l'acier à certaines conditions fut également prise en considération.Il fut démontré que le 12AA inhibait les corrosions partielles et démontrait une corrosion anodique légèrement plus inhibée. Ceci nous a donc indiqué que cet inhibiteur était de type mixte. Le mécanisme de protection de la corrosion se faisait par adsorption de l'inhibiteur 12AA et cela procurait une protection hydrophobique contre les ions corrosifs avec une efficacité de 98%. L'adsorption de 12AA à la surface de l'acier suit le modèle de l'isotherme de Langmuir. L'énergie de Gibbs correspondante de cette adsorption a été calculée comme étant environ −26 (sans CO2) et −28 kJ mol−1 (saturée en CO2 et 0.5 M HCl). Ceci a indiqué que la formation de la couche (composée d'une épaisseur) est amorphe et que cela est causé par la répulsion engendrée avec les groupes voisins de même charge positive et par le caractère très hétérogène de la surface. L'étude a aussi démontré que le 12AA peut être très efficace contre la corrosion de l'acier carbone et ce avec une grande variété d'électrolytes et d'acides. Il est important de mentionner que l'inhibiteur est inefficace contre l'acide nitrique et sulfurique. L'inhibiteur peut aussi réduire la corrosion lorsque le pH est élevé, mais voit son efficacité réduite dans ces conditions en raison de l'augmentation de sa solubilité. Finalement, le 12AA semble aussi performant avec toutes les rugosités. L'effet et le type de flux d'une solution de HCl saturée en dioxyde de carbone fut aussi étudié avec l'aide d'une électrode à disque rotatif. L'inhibiteur 12AA (3mM) se démontra très performant à contrer la corrosion dans un espace carré et avec un électrode à disque rotatif. Cependant, lorsque la concentration fut réduite à 1mM la performance de l'inhibiteur diminua et son nombre de Reynolds fut augmenté. Ceci fut causé par désorption de 12AA de la surface de l'acier. Cet inhibiteur ne fut donc pas efficace à protéger l'acier carbone dans ces conditions.L'étude de l'inhibiteur 11AA donna des résultats similaires. Cependant, la protection de l'acier carbone fut plus efficace qu'avec le 12AA à cause que le 11AA est capable de couvrir une surface plus importante tout en faisant une couche plus compacte.
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Cao, Liu. "Corrosion and Stress Corrosion Cracking of Carbon Steel in Simulated Fuel Grade Ethanol." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1345141634.
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Soh, Tedric. "Conductive polymer coating for corrosion protection of steel." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112584.
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There is an increasing interest in exploring the use of conductive polymers for protecting metals from corrosion. The corrosion resistance of steel coated with the conductive polymer polypheneylenevinylene (PPV) is studied. The corrodant used is deaerated 1% w/w NaCl(aq).The PPV coating is deposited by a homemade spinning coater. The effect of substrate microstructure and surface treatment on PPV coating morphology is investigated. The morphology and surface roughness of the coating are measured by Atomic Force Microscopy (AFM). The PPV coating thickness and substrate surface roughness are measured by profilometer.
Open Circuit Potential (OCP), electrochemical impedance spectroscopy (EIS), linear potentiodynamic voltammetry (Tafel) and optical microscopy were used to characterize the structure and properties of the coatings. The correlation between the coating thickness, the surface treatment of the steel substrate prior to coating, and the corrosion behaviour of PPV coated steel was investigated.
Under the condition of our studies, the level of pH in the solution used for corrosion testing has the strongest effect on the corrosion behaviour of PPV coated steel.
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Palumbo, Nicolino. "Accelerated corrosion testing of steel reinforcement in concrete." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60681.
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In the last few decades, there has been an increasing worldwide problem of deterioration of reinforced concrete structures, caused primarily by the corrosion of the steel reinforcement embedded within the concrete. Several factors can influence the corrosion process in different types of inservice structures. This thesis reviews the basic principles of the reinforcement corrosion. Various protection and rehabilitation schemes that can be undertaken in the repair of deteriorated concrete structures are presented. In particular, three specific types of structures in the Montreal region which have undergone rehabilitation are presented as typical case studies. Additionally, major research work done in the area of reinforcement corrosion over the last twenty years is reviewed.This thesis reports the results of an experimental research program carried out at McGill University dealing with accelerated electrochemical corrosion testing of reinforced concrete. The main objective of this study is to determine the importance and influence of the depth of the concrete cover thickness on the rate of corrosion of steel reinforcement and thereby, on the resistance of concrete. Appropriate conclusions and recommendations regarding the construction variables affecting the corrosion process are brought forth.
These conclusions and recommendations can be summarized.
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Constantinou, Anastasia. "The corrosion of steel reinforcement in carbonated concrete." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362540.
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Holloway, Mark. "Corrosion of steel reinforcement in slag-based concrete." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365811.
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Wong, T. M. "Stress corrosion cracking in a high strength steel." Thesis, University of Canterbury. Engineering, 1986. http://hdl.handle.net/10092/6429.
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This thesis falls into four fields of study.
The first is a survey of relevant literature concerning the many theories of stress corrosion cracking and hydrogen embritt1ement. This includes descriptions of the mechanisms of stress corrosion cracking (SCC) and outlines electromechanical processes and stress - sorption theory. Four widely accepted mechanisms for environment assisted cracking are also outlined. They are, 1) Embritt1ement resulting from accumulated hydrogen at embritt1ement sites, 2) Lowering of surface energy by adsorption of hydrogen, 3) Hydrogen interaction with dislocations, and 4) Lowering of the binding energy by interaction of hydrogen.
The literature survey is a significant part of this thesis. The overall objective of the survey is to review a series of current SCC tests on high strength steels. The principal findings from these previous studies are summarized, they provide concrete evidence for the conclusion that SCC of high strength steels is due to hydrogen embrittlement.
The second part of the project deals with the development of a stress corrosion loading clevis suitable for testing compact tension specimens. Three existing constant load rigs were developed, and equipment was designed for the successful operation of the rigs.
Corrosive environment was applied to the standard compact tension specimen using a novel circulation system based on a magnetic plate stirrer. Corrosive solution (3.5% NaCl) was stirred by the magnetic plate, and the vortex created by the magnetic stirrer was used to create a pumping head.
The third area of work dealt with the testing of compact tension specimens of ULTIMO 200 steel using the developed apparatus. The experimental procedures used are based on the application of linear elastic fracture mechanics to stress corrosion cracking.
The fourth area of work carried out was to perform slot length calibration experiments on CT specimens by using strain gauges.
The results indicated that the specimens pre-cracked in air with a higher dynamic load gave higher threshold stress intensities (KIscc ) than those pre-cracked in air with a lower dynamic load. An electron microscope study indicated evidence of a largely inter granular fatigue crack having occurred in the specimens pre-cracked with a high dynamic load.
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West, Anna Elizabeth. "Contributors to waterside corrosion of soil-steel structures." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45606.
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Soil-steel structures are designed and constructed worldwide for use in civil infrastructure and construction industries. As a result, extensive work has been devoted to understanding the corrosion of zinc and galvanized steel yielding the development of various corrosion models worldwide. Canada does not have a corrosion model required for use in design, but engineers and contractors often use that developed in the United States by the American Association of State Highway and Transportation Officials. This corrosion model defines the recommended range of pH, chloride concentration and soluble sulphate concentration as well as minimum resistivity for unsaturated soil applications. However, these design recommendations and associated corrosion model are often misused in aqueous environments. As a result, many structures have demonstrated significant evidence of premature corrosion raising concerns with the suitability of this corrosion model.
Field testing was conducted on both mechanically stabilized earth retaining walls as well as corrugated steel pipe. Steel samples were extracted for analyses with scanning electron microscope and energy dispersive x-ray spectroscopy while water samples were collected to determine the properties causing degradation. Linear polarization resistance was also completed on two mechanically stabilized earth walls to obtain in-situ corrosion rates.
To complement field work, laboratory experiments were conducted on galvanized steel samples in electrolytes simulating environments satisfying design criteria recommending by the American Association of State Highways and Transportation Officials as well as outside the scope of this model. Relative corrosion rates were calculated from results obtained from accelerated corrosion testing and sample surfaces were analyzed with the use of a scanning electron microscope.
Through laboratory experimentation and field testing it has been discovered that the hardness of water affects the formation of the outermost protective layer on zinc articles, the zinc patina. The following dissertation challenges the appropriateness of durability design criteria and associated corrosion model, defined by the American Association of State Highway and Transportation Officials, for use in aqueous environments while offering guidance on the development of more suitable guidelines for conditions other than unsaturated soil.
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Young, N. P. "The corrosion chemistry of Li2̲SiO3̲ with steel." Thesis, University of Nottingham, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235358.
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Morshed, Ali. "Surface modification for corrosion protection of steel pipes." Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271173.
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De, Rojas Ricardo R. (Ricardo Rafael De Rojas Pando) 1978. "New developments in steel reinforcement protection from corrosion." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8613.
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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2001.Includes bibliographical references (leaves 55-56).
Due to life-cycle costs considerations, the Federal Highway Administration has required that all their new bridge structures have a service life of more than 75 years. The practical use of adequate concrete cover, low water/cement ratio, and corrosion inhibitors and admixtures are not enough to satisfy this requirement. Corrosion still affects the reinforcing steel through the diffusion of chlorides. The steel reinforcement, the last line of defense, has to be addressed in order to protect reinforced concrete structures from corrosion and thus extend the service life. Today, new cost-effective technology has surfaced to address the problem. Nuovinox Stainless-steel clad reinforcing bars, fusion bonded epoxy (3M Skotchkot 426) and the recent Dual Phase Ferritic Martensitic bars (MMFXI/II steels) have emerged. This study describes each new reinforcement protection technology and compares them through cost, service life, availability and resistance considerations. The comparisons show that stainless-steel clad bars have the advantage over all other new reinforcement types. The fusion bonded epoxy closely followed while the MMFX steel, because of its lack of exposure, came in last. A prudent combination of the standard corrosion protection methods with these new technologies in steel reinforcement can potentially provide a cost-effective service of more than 75 years to a structure.
by Ricardo R. De Rojas.
M.Eng.
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Ren, Gang. "Corrosion and passivity of 13Cr supermartensitic stainless steel." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609807.
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Sasaki, Kotaro. "Erosion-corrosion of stainless steel by aqueous slurries." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624961.
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Rajahram, Shiva Suthan. "Erosion-corrosion mechanisms of stainless steel UNS S31603." Thesis, University of Southampton, 2010. https://eprints.soton.ac.uk/195255/.
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Solid particle erosion-corrosion is the wear caused by the combined action of the mechanical process of solid particle erosion and the electrochemical process of corrosion. This joint action leads to a synergistic interaction that enhances the wear rate of the material, causing severe problems to engineering components exposed to these aggressive conditions. This poses a problem to designers and engineers, as there are currently no robust models available to predict erosion-corrosion rates due to the incomplete understanding of the physical erosion-corrosion mechanisms and synergy. The aim of this project is to develop a systematic understanding towards modelling erosion-corrosion by investigating the erosion-corrosion mechanisms of stainless steel UNS S31603. An integrated approach is used in this study consisting of three main thrusts from an environmental, electrochemical and materials perspective. The first part of the thesis, examines the robustness of the semi-empirical model based on an active area principle, which was developed recently at the University of Southampton on a passive metal UNS S31603. Gravimetric experiments were performed using a slurry pot erosion tester. The slurry pot erosion tester was also modified to perform in-situ electrochemical investigations. Results from this novel modification, showed that the erosion-corrosion rates and synergy levels increased with increasing velocity, temperature and sand concentration. Electrochemical current noise measurements for multiple particle impact experiments showed that this was partly due to the continuous rupture of the oxide film leading to an erosion enhanced corrosion synergistic effect. The erosion-corrosion rates were found to be a function of the kinetic energy of the particles, the number and the size of the particles impacting the surface. The amount of charge consumed and the repassivation kinetics were derived from the single particle impact experiments. Lips also appear to crack on the surface believed to be caused by corrosive action accelerating material removal. The results were analysed statistically and for the first time, interaction contour plots have been used to decouple the interactions between the test parameters. These studies showed that the largest interaction occurred between velocity and sand concentration and empirical models were also derived from these analyses. Although the model provided reasonable prediction of the synergy values, the unanswered question of whether the right mechanisms were being modelled formed an important basis for this work. For the first time, in-depth investigation was performed on the evolution of wear on the surface and subsurface of UNS S31603 using SEM, FIB, STEM and TEM. Investigations revealed that a three layer grain structure consisting of nano-grains, micro-grains and deformed bulk grains was seen to evolve with time. An explanation is proposed on reasons why the mass loss rates vary at different stages of erosion-corrosion, by correlating the surface and subsurface wear with the trend of mass loss rate versus time. TEM investigations also revealed the formation of numerous fatigue cracks and folding of lips on the surface believed to be due to strain imposed during repeated particle impact. Other unique features observed are embedment of erodent fragments and chromium oxide layer as well as strain induced phase transformation. It is believed that a thin composite structure consisting of these elements are formed and enhanced by the formation of lips over this structure. All these factors combined with grain refinement and work hardening enhances the fatigue crack formation process. This process is then accelerated by corrosion as confirmed by the higher density of cracks observed in the erosion-corrosion sample, compared to the sample subjected to pure erosion. This is proposed as one of the main corrosion enhanced erosion synergistic mechanism present during erosion-corrosion. Physical models have been developed based on these micro and nano-scale wear observations to integrate the surface and subsurface erosion-corrosion mechanisms. This work has generated an enhanced physical model to explain the erosion-corrosion mechanisms at the subsurface of UNS S31603. The findings of this work would greatly assist engineers and designers in the development of future erosion-corrosion models and in the understanding of synergy between erosion and corrosion
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Saithala, Janardhan R. "Pitting and stress corrosion cracking of stainless steel." Thesis, Sheffield Hallam University, 2007. http://shura.shu.ac.uk/20311/.
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An investigation has been performed to determine the pitting resistance of stainless steels and stress corrosion cracking of super duplex stainless steels in water containing chloride ions from 25 - 170°C. The steels studied are 12% Cr, FV520B, FV566, 304L, Uranus65, 2205, Ferallium Alloy 255, and Zeron 100. All these commercial materials used in very significant industrial applications and suffer from pitting and stress corrosion failures. The design of a new experimental setup using an autoclave enabled potentiodynamic polarisation experiments and slow strain rate tests in dilute environments to be conducted at elevated temperatures. The corrosion potentials were controlled using a three electrode cell with computer controlled potentiostat. The experimental programme to determine pitting potentials was designed to simulate the service conditions experienced in most industrial plants and develop mathematical model equations to help a design engineer in material selection decision. Stress corrosion resistance of recently developed Zeron100 was evaluated in dilute environments to propose a mechanism in chloride solutions at high' temperatures useful for the nuclear and power generation industry. Results have shown the significance of the composition of alloying elements across a wide range of stainless steels and its influence on pitting. Nitrogen and molybdenum added to modern duplex stainless steels was found to be unstable at higher temperatures. The fractographic results obtained using the scanning electron microscope (SEM) has given insight in the initiation of pitting in modem duplex and super duplex stainless steels. A mathematical model has been proposed to predict pitting in stainless steels based on the effect of environmental factors (temperature, chloride concentration, and chemical composition). An attempt has been made to identify the mechanism of SCC in Zeron100 super duplex stainless steel. The proposed empirical models have shown good correlation between predicted pitting potential values with experimental results. It has been shown that the SCC mechanism in Zeron100 supports the slip assisted anodic dissolution model of SCC. The relationship between pitting and stress corrosion in dilute environments is established and empirical equations have been proposed to determine the damage region for wide range of stainless steels.
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Rahgozar, Reza. "Fatigue endurance of steel structures subjected to corrosion." Thesis, University of Bristol, 1998. http://hdl.handle.net/1983/ea197da9-80da-4385-a7ed-eabd7acdedec.
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Ilevbare, Gabriel Oiseomoje. "The inhibition of pitting corrosion in stainless steel." Thesis, University of Cambridge, 1996. https://www.repository.cam.ac.uk/handle/1810/272144.
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Tran, Thu N. B. "Corrosion Mechanisms of Mild Steel in Weak Acids." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1400078277.
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Gowda, Sunil. "MULTI-SCALE EFFECTS OF CORROSION ON STEEL STRUCTURES." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1469007207.
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Gao, Xin. "Localized Corrosion Initiation of Steel in CO2 Environments." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1596657895973621.
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Sergi, George. "Corrosion of steel in concrete : cement matrix variables." Thesis, Aston University, 1986. http://publications.aston.ac.uk/14236/.
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Miyagawa, Toyoaki. "EARLY CHLORIDE CORROSION OF REINFORCING STEEL IN CONCRETE." Kyoto University, 1985. http://hdl.handle.net/2433/74641.
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RUNGTHONGBAISUREE, Somkiat. "FUNDAMENTAL INVESTIGATIONS ON CORROSION DETERIORATION OF STEEL STRUCTURES." Kyoto University, 1991. http://hdl.handle.net/2433/138450.
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Hinton, Jackson Daniel. "Corrosion of Hydraulic Steel Structures and Preventive Measures." Thesis, Mississippi State University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=10978643.
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Hydraulic steel structures (HSS) are key components of U.S. Army Corps of Engineers infrastructure and are subject to corrosive environments, unpredictable loadings, and extreme conditions. Corrosion can take many forms and can cause costly damage to HSS due to inadequate design of protective measures. There are numerous forms of corrosion that have a negative effect on HSS, as well as material properties that need consideration when designing HSS preventive measures. Understanding corrosion and providing proper preventive measures is crucial for HSS. Proper maintenance and repair of these protection systems also play a significant part in corrosion control of HSS.
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Hall, Caroline A. "Corrosion of metals in ester-based lubricants." Thesis, University of Newcastle Upon Tyne, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240745.
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Halsall, John Frederick. "The prevention of biological corrosion and fouling of metals : a study of corrosion processes and the electrochemical methods of controlling corrosion and fouling." Thesis, Bangor University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318073.
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Rybiak, Radoslaw. "Fretting wear of the stainless steel / stainless steel contact under elevated temperature conditions." Ecully, Ecole centrale de Lyon, 2008. https://bibli.ec-lyon.fr/exl-doc/rrybiak.pdf.
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L’usure par fretting qui est considérée comme une nuisance dans plusieurs branches de l’industrie telles que l’aéronautique, l’industrie nucléaire, etc. , consiste en la dégradation de la surface en contact résultant de l’usure qui nécessite une rémise en état ou un remplacement des éléments des machines. Elle est définie comme l’usure qui a lieu pendant un mouvement oscillatoire de faible amplitude entre deux solides apparement immobiles sous une charge normale à la surface de contact. Un tel phénomène est observé surtout dans les assemblages soumis à des vibrations. Dans le cadre de la Thèse, on a étudié le couple tribologique acier Jethete M152 contre acier A-286 à des temperératures élevées afin de créer des conditions identiques à celles qui existent dans un système d’aube de redresseur à calage variable (RCV) d’un compresseur à haute pression d’un moteur double corps-double flux GE90-115B (Fig. 1). En faisant l’analyse des conditions de travail dans un système RCV on peut considérer le processus d’usure d’une douille (eng. Bushing) stationnaire en contact avec un pivot d’aube (vane trunnion) de redresseur. Le mécanisme d’usure correspond à un processus de fretting torsion. Cependant, dans la thèse, on a étudié un fretting type de glissements alternés entre la douille et le pivot sous une sollicitation normale équivalente à une force d’interaction induite par un flux d’air. En effet, nos moyens expérimentaux actuels ne nous permettent pas d’étudier les phénoménes d’usure par torsion. Le mémoire est composé de quatre chapitres. Dans le premier chapitre on réalise une synthèse bibliographique du phénoméne fretting. La problèmatique industrielles est détaillée. Dans le 2ème chapitre sont présentés les matériaux utilisés, les moyens experimentaux utilisés ainsi que le formalisme mécanique et ainsi que la méthode de calcul du volume d’usure. Dans le 3ème chapitre l’auteur mène une discussion sur les résultats de fretting sous des sollicitations invariables avec une prise en considération de l’effet de la température sur le comportement tribologique du système étudié. Une analyse approfondie de l’évolution de l’interface en fonction de la température y est présentée. Dans le 4ème chapitre l’usure par fretting est étudiée pour des sollicitations variables équivalentes à celles qui agissent dans le système RCV. On discute de la dynamique d’évolution du troisième corps sous une température variable pendant un seul essai de fretting. Une carte de fretting-usure de l’activation de la couche ‘glaze’ en fonction de la température, de l’amplitude de déplacement et de pression est présentée. En utilisant la propriété d’additivité de l’énergie dissipée, une loi ‘composite’ de l’usure est introduite.