Dissertations / Theses: 'Corrosion effects'

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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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Upchurch, Marian. "The Effects of Chlorine on Boiler Corrosion." TopSCHOLAR®, 1994. http://digitalcommons.wku.edu/theses/954.

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The amount of corrosion of six metal samples was measured by a change in weight over time. The simulated flue gas stream consisted of 0.2% SO2,14% C02 / and 4% O2, with the HC1 percentage varied from 0.2% to 0.0% and the balance of gas being N2. A Lindbergh Three Temperature Tube Furnace was used to house the metal samples at 100°C, 200°C, and 600°C while being subjected to the simulated flue gas stream. The six metal samples were chosen on the frequency of industrial use. Two carbon steels, C1018 and C1010, contain no chromium and were chosen because of their popularity in older coal combustor systems. The other four samples, F l l , F22, Alloy 800, and 310 SS, are chromium containing metals that were chosen to indicate corrosion inhibitory effects. These four chromium containing samples are commonly used for replacement parts in areas that are prone to high corrosion effects. Weight loss due to corrosion shows a direct relationship to the concentration of HC1 in the flue gas stream for the F l l , F22, and C1018 samples. The greatest amount of weight loss was seen in the 0.2% HC1 and the least for the three samples when there was no HC1 in the flue gas stream. The C1010 sample had the greatest amount of weight loss under the 0.01% HC1 concentration, slightly less for the 0.2% HC1, and finally a weight gain for the 0.0% HC1 run. At no concentration did samples Alloy 800 and 310 SS exhibit any weight change. As for temperature considerations, the greatest amount of change in the samples was seen for the 600°C runs. The 200°C run produced no change in weight for any of the samples, due to the lack of condensation that would facilitate corrosion at low temperatures. For the 100°C runs, the flue gas containing 0.2% HC1, 0.2% S02,14% SO2,4% O2, and the balance N2, caused a change in weight for F l l , F22, C1010, and C1018. This change was not as great as that for the 600°C run. The other two 100°C runs produced no change in weight. Chromium content of the metals can also be related to the amount of corrosion. The high percentage chromium metals, Alloy 800 and 310 SS, showed no weight change in any of the runs. Low chromium containing samples, Fll and F22, showed a loss of weight at all 600°C runs and also for the 100°C subjected to the 0.2% HC1 flue gas stream. The C1010 and C1018 samples contain no chromium and have the most erratic results. These samples gained in weight for the 600°C run for the 0.0% HC1 gas and lost weight for the two other 600°C runs. Also, weight loss for these samples was observed for the 100°C run under 0.2% HC1. Corrosion of the samples begins and proceeds rather quickly until an oxide layer is formed. Once the oxide layer has formed, the amount of corrosion is dependent on the stability of that layer and the diffusion rate of the gases.

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Liu, Xiaodong. "Effects of stress on intergranular corrosion and intergranular stress corrosion cracking in AA2024-T3." Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1133313637.

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Stanish, Kyle David. "Corrosion effects on bond strength in reinforced concrete." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq29397.pdf.

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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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Namahoot, Jutatip. "Effects of deformations on corrosion of Al-Mn alloys." Thesis, University of Birmingham, 2005. http://etheses.bham.ac.uk//id/eprint/108/.

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Wrought Al-Mn alloys can develop a thin deformed layer on the surface as a result of hot and cold rolling. Subsequent heat-treatment precipitates fine secondary intermetallic particles which effect corrosion susceptibility. This work focuses on the effect of surface preparation and deformation on the electrochemical behaviour of Al-Mn alloys. The first part of the work investigated the effect of surface preparation such as mechanical grinding and polishing, alkaline etching and desmutting, and nitric acid treatment on electrochemical behaviour of an Al-1Mn-0.4Fe-0.3Si model alloy. Different surface preparations of this alloy show different electrochemical behaviour. In the second part of the work, the electrochemical reactivity of the surface layers of commercial rolled AA3005 sheet was investigated by profiling through the surface with GDOES (glow discharge optical emission spectroscopy). The microstructure and electrochemical reactivity was examined at different depths in order to compare the behaviour of the surface layers with that of the bulk alloy. In order to understand the role of deformation on corrosion behaviour of Al-Mn alloy, an Al-1Mn-0.4Fe-0.3Si model alloy was deformed by uniaxial compression and equal channel angular extrusion (ECAE) and followed by annealing. It was found that deformation is likely to have two effects on the surface of Al-Mn alloy. One effect is to cause the precipitation of particles that act as local cathodes and pit initiation sites. The other effect is that formation of precipitates will deplete the adjacent matrix in solute, making it more susceptible to dissolution.

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Kao, Tsu-Mu 1958. "Incorporating flow-accelerated corrosion effects into probabilistic risk assessment." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9402.

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Bakare, Mayowa Sunday. "The effects of microstructural modifications on corrosion resistance of metallic corrosion resistant materials Inconel 625 and FeCrMoCB." Thesis, University of Nottingham, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.546474.

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Malka, Ramakrishna. "Erosion Corrosion and Synergistic Effects in Disturbed Liquid-Particle Flow." Ohio University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1125603562.

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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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Forslund, Mattias. "Micro-galvanic effects and corrosion inhibition of copper-zinc alloys." Doctoral thesis, KTH, Yt- och korrosionsvetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-151189.

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With the advancement and accessibility of local probing techniques that can operate at the submicron scale it has become possible to analyse the local corrosion properties of industrially important metallic materials and relate these properties to microstructure characteristics of the same materials. In this doctoral study the focus has been on copper-zinc samples, both as industrial brass alloys and as micro-patterned copper-zinc samples. They have been exposed to dilute chloride solutions and to an atmosphere that mimics indoor conditions that cause corrosion. The main goal has been to investigate micro-galvanic effects caused by surface heterogeneities in the copper-zinc samples, and the corrosion inhibition ability of a self-assembled octadecanethiol (ODT, CH3(CH2)17SH) monolayer when applied to these heterogeneous samples. The local chemistry, local electrochemistry, and local surface chemistry in the presence of the copper-zinc galvanic couplings have been elucidated, and their importance has been investigated for corrosion initiation, propagation, termination, and inhibition. A broad spectrum of local probe techniques has been utilised. They include optical microscopy (ex situ and in situ), electrochemical techniques, scanning electron microscopy with energy dispersive spectroscopy, atomic force microscopy, scanning Kelvin probe force microscopy and confocal Raman spectroscopy. In addition, infrared reflection absorption spectroscopy (in situ) and vibrational sum frequency spectroscopy have been employed to analyse the formation of corrosion products and monitor the corrosion kinetics. A characteristic selective zinc dissolution process was triggered in non-metallic inclusions when a brass alloy was exposed to 1 mM NaCl. Disc-like corrosion areas spread radially outwards from the inclusions, the shape and termination of which was attributed to accessibility to chloride ions. An ODT-layer deposited on brass retarded access to chloride ions at the brass surface and slowed down the radial corrosion process. Instead a delayed formation of filiform-like corrosion was observed. Upon exposure of the copper-zinc patterned sample to humidified air containing formic acid, micro-galvanic effects were induced by the copper patches on zinc that accelerated the zinc dissolution in the thin aqueous adlayer with concomitant precipitation of zinc formate. The micro-galvanic effects not only resulted in accelerated corrosion rates for zinc, but also in broadening of shapes and atomic structures for the corrosion products formed. Crystalline zinc oxide and zinc formate were observed on the copper-zinc patterned samples, whereas amorphous zinc oxide and zinc formate were formed on the bare zinc surface. Micro-galvanic effects occurred in the two-phase Cu40Zn (Cu with 40 wt% Zn) brass alloy as well, induced by more zinc-rich beta-phase grains surrounded by an alpha matrix with lower zinc-content. The application of a self-assembled monolayer of ODT for corrosion inhibition of pure zinc and the patterned copper-zinc samples was also explored. In situ infrared reflection absorption spectroscopy analyses showed that ODT initially reduced the rate of zinc formate formation on pure zinc and on the copper-zinc micro-patterned sample. However, the inhibition efficiency was slightly reduced with exposure time due to local removal of ODT on pure zinc and on the micro-patterned samples. This caused micro-galvanic effects that resulted in increased rates of zinc formate formation on the ODT-covered samples – even higher than on the uncovered samples. When applied to the single-phase Cu20Zn alloy, ODT resulted in a corrosion inhibition that was comparable to that of pure copper, a metal for which ODT has shown very good corrosion inhibition. On double-phase Cu40Zn local galvanic effects resulted in less efficient corrosion inhibition and more abundant corrosion products than on Cu20Zn. Based on vibrational sum frequency spectroscopy, the ODT-layer retained its well-ordered molecular structure throughout the exposure to both Cu20Zn and Cu40Zn. In all, the inhibiting action of the ODT-layer was attributed to the transport hindrance of corrosion promoters (O2, H2O, and HCOOH) to the brass surface. This result suggests that ODT can function as a temporary corrosion inhibitor for brass exposed to benign indoor environments.
Med utvecklingen av och tillgången till lokala analysmetoder som kan ge information med en lateral upplösning på mindre än en mikrometer har det blivit möjligt att analysera lokala korrosionsegenskaper hos industriellt viktiga metalliska material och relatera dessa egenskaper till mikrostrukturen hos samma material. I doktorsavhandlingen har denna möjlighet utnyttjats för koppar-zinkprover, dels som industriella mässingslegeringar dels som mikro-mönstrade koppar-zinkprover, som exponerats för utspädda kloridlösningar samt för en atmosfär som kan efterlikna den atmosfäriska korrosionen inomhus. Det huvudsakliga målet har varit att undersöka dels mikro-galvaniska korrosionseffekter som orsakas av heterogeniteter på koppar-zinkytorna dels korrosionsförmågan hos självorganiserande monolager av oktadekantiol (ODT, CH3(CH2)17SH) vid adsorption på dessa heterogena ytor. På så vis har den lokala kemin, ytkemin och elektrokemin kunnat klarläggas i närvaro av galvaniska effekter, och dess betydelse har undersökts för korrosionsprocessens initiering, propagering, terminering och inhibering. Ett brett spektrum av lokala analysmetoder har utnyttjats. De innefattar ljusoptisk mikroskopi (ex situ och in situ), elektrokemiska metoder, svepelektronmikroskopi med energidispersiv röntgen-spektroskopi, atomkraftsmikroskopi för mikro-kartering och Voltapotentialmätningar samt konfokal Raman-spektroskopi. Dessutom har infrarödreflektions absorptionsspektroskopi (in situ) och vibrationssummafrekvens spektroskopi (engelska: vibrational sum frequency generation) använts. När en mässingslegering exponerades för 1 mM NaCl observerades en selektiv utlösning av zink med karakteristiskt utseende som växte radiellt från icke-metalliska inneslutningar för att bilda cirkulärt formade korrosionsområden. Formen och termineringen av denna korrosionsprocess bestäms av tillgången på kloridjoner. När ett monolager av ODT adsorberades på mässingslegeringen hämmades tillgången av kloridjoner på mässingsytan och den radiella korrosionsprocessen stannade upp. Istället iakttogs en fördröjd bildning av s.k. filiform korrosion. Vid exponering av mikro-mönstrade koppar-zinkprover för befuktad luft med låga tillsatser av myrsyra inducerades mikro-galvaniska effekter i gränsen mellan koppar och zink som accelererade utlösningen av zink i den adsorberade fuktfilmen på provet, under samtidig utfällning av zinkformat. De mikro-galvaniska effekterna resulterade inte bara i förhöjda korrosionshastigheter jämfört med de på ren zink, utan även i andra faser hos bildade korrosionsprodukter. På de mikro-mönstrade koppar-zinkproverna bildades kristallint zinkoxid och zinkformat, under det att amorft zinkoxid och zinkhydroxyformat bildades på ren zink. Mikrogalvaniska effekter observerades även i den tvåfasiga mässingslegeringen Cu40Zn (Cu med 40 vikt-% Zn) orsakade av kontakten mellan den mer zinkrika beta-fasen och den omgivande alfa-fasen med lägre zinkhalt. Appliceringen av ett självorganiserat monolager av ODT för korrosionsinhibering av ren zink och koppar-zinkprover har också undersöks. In situ infrarödreflektions absorptionsspektroskopi visade att adsorberat ODT initialt hämmade bildningen av zinkformat på ren zink och på de mikro-mönstrade koppar-zinkproverna. Med tiden minskade ODTs korrosionsinhiberings-förmåga på grund av att ODTs vidhäftning lokalt försvann. De mikro-galvaniska effekter som därigenom uppstod resulterade i bildandet av zinkformat som med tiden blev snabbare på de ODT-belagda proverna än på motsvarande prover utan ODT. När ODT applicerades på den enfasiga mässingslegeringen Cu20Zn resulterade detta i en korrosionsinhibering som var jämförbar med den på ren koppar, en metall på vilken ODT tidigare visat mycket bra korrosionsskydd. På den tvåfasiga mässingslegeringen Cu40Zn ledde lokala galvaniska effekter till en mindre effektiv korrosions-inhibering och en rikligare mängd korrosionsprodukter än på Cu20Zn. Baserat på vibrationssummafrekvens spektroskopi behöll ODT-lagret dess välordnade struktur under hela exponeringen på både Cu20Zn och Cu40Zn. ODTs korrosionsinhibering tillskrivs främst transport-hämningen av korrosionsstimulatorer (O2, H2O och HCOOH) till mässingsytan och antyder att ODT kan fungera som en temporär korrosionsinhibitor för mässing i milda inomhusmiljöer.

QC 20140915

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Batt, Joanna Mary. "The biological effects of titanium corrosion products on gingival epithelium." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7810/.

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Implanted titanium (Ti) devices such as dental implants have been shown to produce metallic species within adjacent tissues. The effect of the presence of these species within oral epithelial tissues is currently not well characterised or known. This thesis investigates the effects of TiO$_2$ nanoparticles (TiO$_2$ NPs) at a range of concentrations on oral epithelial cells in the context of cell viability, cellular functions and interactions via a variety of methods. A co-culture model was established, and the difficulties of using a nano-scale insoluble stimulus were explored, and high content screening techniques were shown to be potentially more appropriate methods than conventional assays in this context. Interactions between TiO2 NPs and oral epithelial cells were imaged and investigated using a variety of imaging techniques. Oral epithelial cells were shown to take up TiO$_2$ NPs within vacuole type structures. Cell viability appeared to not be affected at lower concentrations. Gene expression changes of oral epithelial cells in response to TiO$_2$ NPs in the presence and absence of pathogenic bacteria were investigated. Cytokines important in cell-cell signalling were shown to bind TiO$_2$ NPs, therefore creating potential for TiO$_2$ NPs within tissues to modify immune responses within tissues adjacent to implanted Ti devices.

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Zhang, Yan. "Relative Effects of Water Chemistry on Aspects of Iron Corrosion." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/35501.

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The net present replacement value of all publicly and privately owned potable water pipes in the U.S. is on the order of $2.4 trillion dollars, and costs associated with deteriorating iron pipes is billions of dollars per year. Problems arising from iron corrosion include reduced lifetime of the material, scale buildup and energy loss, nonuniform corrosion and leaks, catastrophic failure, "red water," disinfectant loss and bacterial re-growth. Iron corrosion is a very complicated process and is affected by many factors. This research focused on the effect of disinfectant type, sulfate/chloride ratios, nitrate concentration, and magnesium hardness on iron corrosion. For the waters tested, chlorine better controlled red water and microbial activity in the bulk solution than chloramine. Changes in the sulfate/chloride ratio did not have a large effect on iron corrosion. High levels of nitrate increased the rate of chlorine decay as a result of free ammonia formation, and also increased the release of iron. Increased magnesium and zinc decreased the red water caused by high silicate. Microbiological activity is important in iron corrosion, and control of re-growth in water distribution systems is a major challenge for water utilities. A separate study examined the inter-relationship between iron corrosion and bacterial re-growth, with a special focus on the potential of iron pipe to serve as a source of phosphorus. Under some circumstances corroding iron and steel may serve as a source for all macronutrients necessary for bacterial re-growth including fixed carbon, fixed nitrogen and phosphorus. Conceptual models and experimental data illustrate that levels of phosphorus released from corroding iron are significant relative to that necessary to sustain high levels of biofilm bacteria. Consequently, it may be more difficult to limit re-growth on iron surfaces by limiting phosphorus in the bulk water.
Master of Science

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Jauseau, Nicolas. "Multiphase Flow Effects on Naphthenic Acid Corrosion of Carbon Steel." Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1354149810.

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Lewis, Jeremy D. "The Effects of Corrosion on Reinforced Concrete with Fiber Addition." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1355171708.

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Liang, Dong. "Environmental and Alloying Effects on Corrosion of Metals and Alloys." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1243995273.

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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 Â½ 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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Sapiro, David O. "The Effects of Alloy Chemistry on Localized Corrosion of Austenitic Stainless Steels." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/1087.

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This study investigated localized corrosion behavior of austenitic stainless steels under stressed and unstressed conditions, as well as corrosion of metallic thin films. While austenitic stainless steels are widely used in corrosive environments, they are vulnerable to pitting and stress corrosion cracking (SCC), particularly in chloride-containing environments. The corrosion resistance of austenitic stainless steels is closely tied to the alloying elements chromium, nickel, and molybdenum. Polarization curves were measured for five commercially available austenitic stainless steels of varying chromium, nickel, and molybdenum content in 3.5 wt.% and 25 wt.% NaCl solutions. The alloys were also tested in tension at slow strain rates in air and in a chloride environment under different polarization conditions to explore the relationship between the extent of pitting corrosion and SCC over a range of alloy content and environment. The influence of alloy composition on corrosion resistance was found to be consistent with the pitting resistance equivalent number (PREN) under some conditions, but there were also conditions under which the model did not hold for certain commercial alloy compositions. Monotonic loading was used to generate SCC in in 300 series stainless steels, and it was possible to control the failure mode through adjusting environmental and polarization conditions. Metallic thin film systems of thickness 10-200 nm are being investigated for use as corrosion sensors and protective coatings, however the corrosion properties of ferrous thin films have not been widely studied. The effects of film thickness and substrate conductivity were examined using potentiodynamic polarization and scanning vibrating electrode technique (SVET) on iron thin films. Thicker films undergo more corrosion than thinner films in the same environment, though the corrosion mechanism is the same. Conductive substrates encourage general corrosion, similar to that of bulk iron, while insulating substrates supported only localized corrosion.

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19

Hill, Lisa. "On the effects of special boundary geometries on intergranular corrosion and grain boundary evolution in aluminium." Thesis, Swansea University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678451.

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Zarouni, Ismael. "Effects of admixtures on chloride-induced corrosion of steel in concrete." Thesis, University of Leeds, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438568.

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Bogen, Daniel J. "Effects of Manufacturing Defects on the Corrosion of Additively Manufactured AlSi10Mg." Youngstown State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1596641889374996.

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22

Wang, Hua. "Effects Of Microbial Attachment And Biofilm Formation On Microbiologically Influenced Corrosion." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1396543805.

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23

Abdulwahhab, Yousuf. "Investigations of Corrosion Effects at High Temperatures and High Pressure Conditions." Thesis, Curtin University, 2020. http://hdl.handle.net/20.500.11937/84146.

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Corrosion in the oil and gas industry is one of the outstanding challenging problems due to material degradation. This thesis deals with the nature of the passive film formed on 316LSS and its protective mechanism in oil and gas production where anaerobic CO2 environments exist as well as high temperature and pressure. In addition to the effect of different CO2 partial pressure. This thesis are also study the effects of nitrite ions on the corrosion inhibition of carbon steel in the absence and presence of chloride solution at high temperature.

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Kang, Chiun-Chia. "Moisture and stress effects on fretting between steel and polyimide coatings." Diss., This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06062008-171727/.

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25

Miller, Jason. "Devitrification Effects on the Structure and Corrosion of an Fe-based Bulk Metallic Glass." Cleveland, Ohio : Case Western Reserve University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1252371978.

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Thesis(M.A.)--Case Western Reserve University, 2010
Title from PDF (viewed on 2010-01-28) Department of Materials Science and Engineering Includes abstract Includes bibliographical references and appendices Available online via the OhioLINK ETD Center

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26

Linder, Jenny. "Alcoholate corrosion of aluminium in ethanol blends -the effects of water content, surface treatments, temperature, time and pressure." Thesis, KTH, Skolan för kemivetenskap (CHE), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145856.

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As it becomes more important to replace fossil fuels with alternative fuels, biofuels like ethanol are becoming more commercially used. The increased use of ethanol brings good influences such as lower impact on the environment. However, the use of ethanol can also bring negative effects regarding corrosion of metals. In the automotive industry aluminium has been seen affected by a novel very aggressive corrosion phenomenon, alcoholate corrosion. This master thesis investigation has investigated the effect of a few parameters of importance for alcoholate corrosion; water, temperature, time and pressure. The aluminium alloys AA6063 and A380 have been investigated and the capacity of five different surface treatments of AA6063 has been tested to observe if they inhibit the effect of alcoholate corrosion. Throughout the experiments the water dependence of alcoholate corrosion has showed to be of large importance for the corrosion process. An increase in water content will postpone the start of alcoholate corrosion or prevent corrosion to occur. A correlation between temperature and time has been observed. Higher temperatures results in a shorter time period of exposure before alcoholate corrosion occurs, and vice versa. The effect of different pressures was investigated and showed no effect on alcoholate corrosion when using pressurisation with the inert nitrogen gas. All surface treatments revealed a capacity to protect the aluminium alloy against alcoholate corrosion to different extent. The electroless nickel plating seemed to prevent alcoholate corrosion while the Keronite coating seemed more sensitive to this form of corrosion.

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Mitre, Cirlei Igreja do Nascimento. "Efeitos de um campo magnético aplicado na corrosão de cobre monitorado in situ por RMN." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/75/75135/tde-04082017-151644/.

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Nesta dissertação de mestrado se monitorou in situ e ex situ a corrosão de corpos de prova de cobre metálico por ressonância magnética nuclear no domínio do tempo (RMN-DT). A reação ocorreu em solução aquosa de HCl 1 mol L-1 fornecendo íons de cobre Cu2+ como produtos da corrosão. A corrosão foi monitorada com um espectrômetro RMN de bancada, através da correlação entre os tempos de relaxação transversal (T2) adquiridos por meio da sequência de pulso CPMG e a concentração de Cu2+ na solução. As reações foram estudadas usando como corpos de prova placas e cilindros de cobre, na presença e ausência de campo magnético e na presença e ausência de potencial elétrico aplicado. Esses experimentos foram realizados para estudar o efeito das forças magnéticas que podem afetar as reações. Os experimentos de RMN-DT-eletroquímica (RMN-DT-EQ) foram executados usando o corpo de prova em formato de placa de cobre como eletrodo de trabalho, fio espiral de platina como contra eletrodo e um eletrodo de referência de Ag/AgCl (KCl 3 mol L-1). Os experimentos sem potencial aplicado foram realizados usando-se somente os corpos de prova de cobre na solução de HCl. Os resultados mostraram que o campo magnético não alterou o efeito da corrosão quando se aplicou um potencial de 1V. No entanto a reação foi inibida na corrosão sem potencial elétrico aplicado. Esses resultados levaram a hipótese de que, na reação com potencial aplicado, a força de Lorentz foi minimizada pelas forças de gradiente de campo magnético e força de gradiente da concentração de espécies paramagnética. No caso da corrosão sem potencial elétrico aplicado, a hipótese para a inibição da corrosão foi que as forças de gradiente mantiveram os íons de cobre na interface corpo de prova/solução, o que dificultou a reação. O efeito do campo magnético sobre a superfície do cilindro de cobre ao final do processo de corrosão também foram analisados pelas técnicas de microscopia eletrônica de varredura e microscopia de força atômica enquanto que a solução resultante do processo de corrosão teve os valores da concentração de íons Cu2+ quantificados pelas espectroscopias de absorção no ultravioleta e visível e de absorção atômica com chama.
In this Masters dissertation the corrosion of metallic copper samples was monitored in situ and ex situ by time domain nuclear magnetic resonance (TD-NMR). The reaction was performed in an aqueous solution containing HCl (1 mol L-1), where Cu2+ ions were the corrosion products. A benchtop NMR spectrometer was used to monitor the reaction through the correlation between the transverse relaxation times (T2), acquired with the CPMG pulse sequence, and the concentration of Cu2+ in the solution. The reactions were studied using copper plaques and cylinders in the presence and absence of a magnetic field and in the presence and absence of an applied potential. These experiments were performed to study the effect of the magnetic forces which affect reactions with and without an applied potential. The coupling experiments between TD-NMR and electrochemistry (EC-NMR) were performed using a copper plaque as a working electrode, a platinum wire in a spiral shape as a counter electrode and a Ag/AgCl KCl 3 mol L-1 reference electrode. Experiments in which no potential was applied were performed by inserting the copper sample in an HCl aqueous solution. Results showed that the magnetic field didn’t alter the corrosion process when a 1V potential was applied but it did inhibit the corrosion of copper when no potential was applied. These results lead to the hypothesis that, in the reaction with an applied potential, the Lorentz force was minimized by the forces created by the magnetic field and the concentration gradient of the paramagnetic species (Cu2+). In the case of corrosion experiments without an applied potential a possibility is that the forces created by the concentration gradient force copper ions to stay on the interface copper/solution, which hinders the reaction. The effect of the magnetic field on the surface of the copper cylinder at the end of the corrosion process was also analysed by scanning electron microscopy and atomic force microscopy while the concentration of Cu2+ in the solution was measured by UV-vis spectroscopy and flame atomic absorption spectrometry.

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Curbo, Jason Wayne. "A preliminary investigation of the effects of environmentally assisted cracking on natural gas transmission pipelines." Thesis, Texas A&M University, 2005. http://hdl.handle.net/1969.1/2357.

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Concepts for the development of a model to predict natural gas transmission pipeline lifetime in a corrosive environment are constructed. Primarily, the effects of environmentally assisted cracking (EAC) are explored. Tensile test specimens from a sample of API 5L X-52 pipeline were tested in a simulated groundwater solution and subsequently analyzed. The results suggested that the simulated environment ultimately reduced the ductility of the test specimens; however, no evidence of ??classical?? stress corrosion crack morphology was discovered. However, corrosion pits up to 0.75 mm (0.03 in) were revealed during metallographic analysis. A Marin factor analogy and an energy method concept are suggested and explored. Ultimately, the test data set was too small for the results to be of any directly applicable significance.

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Huang, Lei. "Investigation of Environmental Effects on Intrinsic and Galvanic Corrosion of Mild Steel Weldment." Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1338567512.

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30

Qiu, Ping. "Quantified In Situ Analysis of Initial Atmospheric Corrosion : Surface heterogeneity, galvanic effects and corrosion product distribution on zinc, brass and Galvalume." Doctoral thesis, KTH, Korrosionslära, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-34096.

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The interaction of the surface of a pure metal or an alloy with the surrounding atmosphere occurs in a highly complex interfacial regime. During atmospheric corrosion this interfacial regime involves the metal surface, often covered by a naturally formed oxide layer of a few nanometers thickness; an aqueous adlayer, typically with a thickness of a few to a few tens of nanometers, and the atmosphere from which airborne particles, oxygen, and gaseous pollutants dissolve into the adlayer and influence the atmospheric corrosion process. This thesis work is mainly concerned with the initial atmospheric corrosion of zinc and brass induced by carboxylic acids (120 parts per billion of formic, acetic, or propionic acid) in laboratory air with 90% relative humidity. This model system has been chosen to mimic indoor corrosion with carboxylic acids as major corrosion stimulators. The study forms part of a broader research program with the ultimate goal to provide a computer model of the early stages of atmospheric corrosion of copper, zinc and copper-zinc alloys, induced by carboxylic acids. Particular emphasis has been given to identify and quantify the corrosion products formed and to determine their lateral distribution over the corroding surface. This has been accomplished through a multi-analytical approach in which two main techniques are infrared reflection absorption spectroscopy (IRAS) which can identify and quantify corrosion products with a relative accuracy of about 10%, and confocal Raman microspectroscopy (CRM) which can identify and resolve corrosion products with a surface lateral resolution of better than one micrometer. The corrosion products identified on pure zinc are zinc oxide (ZnO) and various forms of Zn-carboxylates. On brass, the main corrosion products identified are a cuprite (Cu2O)-like phase and various forms of Zn-carboxylates. For pure zinc and brass the formation rates of corrosion products in presence of the investigated acids depend, among others, on their deposition velocity and acid strength. The interaction of pure zinc and brass with humidified air containing carboxylic acids follows two spatially separated main pathways: a proton-induced dissolution of metal ions followed by the formation of oxides, and a carboxylate-induced dissolution followed by the deposition of metal carboxylates. When applying this multi-analytical approach, it has been possible to distinguish between anodically and cathodically active areas for brass, but not for pure zinc. Galvanic effects have been shown to play a significant role during the initial corrosion of brass. Further evidence of the selective formation of corrosion products has been found when exploring the more complex heterogeneous surface of Galvalume, a commercial aluminum-zinc alloy coating. This material has been exposed to humidified laboratory air with additions of carbon dioxide (CO2) and sodium chloride (NaCl) and to a marine atmospheric environment. Initiated in the interdendritic zinc-rich areas, a uniform aluminum oxide (Al2O3) layer is formed. This oxide exhibits an inhibiting effect on the subsequent formation of other corrosion products, including aluminum oxyhydroxide (AlOOH), aluminum hydroxide (Al(OH)3), ZnO, zinc hydroxycarbonate and zinc hydroxychloride.
QC 20110607

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31

Carvalho, Maria Leonor. "Corrosion of copper alloys in natural seawater : effects of hydrodynamics and pH." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066304/document.

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Cette thèse, réalisée en étroite collaboration avec le partenaire industriel RSE S.p.A (Italie), s’inscrit dans le cadre du projet européen BIOCOR ITN. Les alliages de cuivre habituellement utilisés dans les circuits de refroidissement de centrales électriques peuvent être affectés par la biocorrosion induite par la formation d’un biofilm. L’objectif de ce travail était d’étudier the comportement à la corrosion de l’alliage 70Cu-30Ni et d’un laiton contenant 2% d’aluminium en milieu marin, dans des conditions industrielles réelles (expériences sur le terrain) et en laboratoire. L’influence de différents paramètres, tels que la solution (eau de mer naturelle filtrée (FNSW) vs eau de mer artificielle (ASW)), la concentration en biomolécules (biomolécules naturellement présentes dans l’eau de mer vs une protéine modèle, l’albumine de sérum bovin (BSA)), l’hydrodynamique (conditions statiques, sous circulation et agitation, électrode à anneau tournant) et le pH (8,0 ; 6,0 et 3,7), a été évaluée. Sur le terrain, le comportement global à la corrosion et les traitements antifouling ont été suivis en utilisant des techniques électrochimiques (potentiel de corrosion Ecorr vs temps, LPR), gravimétriques (pertes de masse) et génétiques. En laboratoire, des mesures électrochimiques (Ecorr vs temps, courbes de polarisation, spectroscopie d’impédance électrochimique), réalisées pendant les toutes premières étapes de formation des couches d’oxydes (1 h d’immersion), ont été combinées à des analyses de surface par XPS et ToF-SIMS. A partir des expériences sur le terrain, l’analyse microbiologique et moléculaire des biofilms formés sur les deux alliages de cuivre dans l’eau de mer naturelle montre la présence des espèces bactériennes Marinobacter, Alteromonas et Pseudomonas. In the case of Al brass, the single experimental loop illustrates both anodic charge transfer and anodic mass transport. A partir des expériences en laboratoire, des modèles sont proposés pour analyser les données d’impédance obtenues à Ecorr. Dans le cas de 70Cu-30Ni, la boucle HF illustre principalement le transfert de charge anodique (diamètre égal à Rta) ; alors que la boucle BF est liée au transport de matière anodique et au blocage partiel de la surface par CuCl. Dans le cas du laiton, la seule boucle expérimentale illustre à la fois le transfert de charge anodique et le transport de matière anodique. Le comportement électrochimique et la composition chimique de surface de l’alliage 70Cu-30Ni sont similaires dans ASW et dans FNSW statiques, du fait de la faible concentration en biomolécules dans FNSW. En comparaison de l’alliage 70Cu-30Ni dans ASW statique sans biomolécules, pour lequel une couche duplex épaisse (couche externe de Cu2O redéposé et couche interne de nickel oxydé) est montrée, la présence de BSA conduit à une couche mixte d’oxydes de Cu et de Ni d’épaisseur plus faible ; les résultats montrent aussi un ralentissement de la réaction anodique et un faible effet d’inhibition de la corrosion en présence de BSA. Sous circulation et agitation, une couche mixte d’oxydes de Cu et de Ni, de très faible épaisseur, est obtenue. Pour les deux alliages dans FNSW, le courant de corrosion icorr estimé à partir de Rta est indépendant de la vitesse de rotation de l’électrode tournante, du fait de la compensation des effets du potentiel et du transport de matière. Pour 70Cu-30Ni dans FNSW statique, la réaction anodique est ralentie à pH acide (effet cinétique). Pour le laiton, un effet d’inhibition de la corrosion est montré à pH acide, et plus le pH est acide, plus la réaction anodique est lente. Pour 70Cu-30Ni, l’épaisseur de la couche d'oxyde augmente avec la diminution du pH, dans le cas du laiton il est indépendante du pH. La composition chimique de la couche d'oxyde semble avoir un effet sur la quantité de protéines adsorbées et l'épaisseur équivalente calculée de la couche organique est très faible (quelques Å pour 70Cu-30Ni et 1 Å pour laiton)
This thesis was carried out in the frame of the BIOCOR ITN European project, in close collaboration with the industrial partner RSE S.p.A. (Italy). Copper alloys commonly used in cooling systems of power plants may be affected by biocorrosion induced by biofilm formation. The main objective of this work was to study the corrosion behavior of 70Cu-30Ni alloy and aluminum brass in seawater environments, under real industrial conditions (field experiments) and in laboratory. The influence of different parameters, such as the solution (filtered natural seawater (FNSW) vs artificial seawater (ASW)), the concentration of biomolecules (biomolecules naturally present in seawater vs a model protein, the bovine serum albumin (BSA)), hydrodynamics (static conditions, under flow and stirring, rotating ring electrode (RRE)) and pH (8.0, 6.0 and 3.7), was evaluated. In field, the overall corrosion behavior and antifouling treatments were monitored using electrochemical (corrosion potential Ecorr vs time, LPR), gravimetric (weight losses) and genetic techniques. In lab, electrochemical measurements (Ecorr vs time, polarization curves, EIS), performed during the very first steps of oxide layers formation (1 h immersion time), were combined to surface analysis by XPS and ToF-SIMS. From field experiments, microbiological and molecular analysis of biofilms formed on both copper alloys in natural seawater indicates the presence of Marinobacter, Alteromonas and Pseudomonas bacterial species. From lab experiments, models are proposed to analyze impedance data obtained at Ecorr. In the case of 70Cu-30Ni, the HF loop illustrates mainly the anodic charge transfer (diameter equal to Rta); whereas the LF loop is related to the anodic mass transport and partial blocking effect by CuCl. In the case of Al brass, the single experimental loop illustrates both anodic charge transfer and anodic mass transport. Similar electrochemical behavior and surface chemical composition of 70Cu-30Ni alloy are obtained in static ASW and FNSW, due to the low biomolecule concentration in FNSW. Compared to 70Cu-30Ni in static ASW without biomolecules, for which a thick duplex oxide layer (outer redeposited Cu2O layer and inner oxidized nickel layer) is shown, the presence of BSA leads to a mixed Cu and Ni oxide layer with a lower thickness; the results also show a slow-down of the anodic reaction and a small corrosion inhibition effect in the presence of BSA. Under flow and stirring, a very thin mixed Cu and Ni oxide layer is obtained. For both alloys in FNSW, the corrosion current icorr estimated from Rta is independent of the rotation speed of the RRE, due to compensated potential and mass transport effects. For 70Cu-30Ni in static FNSW, the anodic reaction is slown down at acidic pH (kinetic effect). For Al brass, there is a corrosion inhibition effect at acidic pH, and the more acidic the pH, the slower the anodic reaction. In the case of 70Cu-30Ni alloy, the oxide layer thickness increases with decreasing pH, whereas for Al brass it is independent of the pH. The chemical composition of the oxide layer seems to have an effect on the amount of adsorbed proteins and the calculated organic layer equivalent thickness is very low (few Å for 70Cu-30Ni and 1 Å for Al brass)

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32

Sapiro, David O. "The Effects of Alloy Chemistry on Localized Corrosion of Austenitic Stainless Steels." Thesis, Carnegie Mellon University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10639516.

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This study investigated localized corrosion behavior of austenitic stainless steels under stressed and unstressed conditions, as well as corrosion of metallic thin films. While austenitic stainless steels are widely used in corrosive environments, they are vulnerable to pitting and stress corrosion cracking (SCC), particularly in chloride-containing environments. The corrosion resistance of austenitic stainless steels is closely tied to the alloying elements chromium, nickel, and molybdenum. Polarization curves were measured for five commercially available austenitic stainless steels of varying chromium, nickel, and molybdenum content in 3.5 wt.% and 25 wt.% NaCl solutions. The alloys were also tested in tension at slow strain rates in air and in a chloride environment under different polarization conditions to explore the relationship between the extent of pitting corrosion and SCC over a range of alloy content and environment. The influence of alloy composition on corrosion resistance was found to be consistent with the pitting resistance equivalent number (PREN) under some conditions, but there were also conditions under which the model did not hold for certain commercial alloy compositions. Monotonic loading was used to generate SCC in in 300 series stainless steels, and it was possible to control the failure mode through adjusting environmental and polarization conditions. Metallic thin film systems of thickness 10-200 nm are being investigated for use as corrosion sensors and protective coatings, however the corrosion properties of ferrous thin films have not been widely studied. The effects of film thickness and substrate conductivity were examined using potentiodynamic polarization and scanning vibrating electrode technique (SVET) on iron thin films. Thicker films undergo more corrosion than thinner films in the same environment, though the corrosion mechanism is the same. Conductive substrates encourage general corrosion, similar to that of bulk iron, while insulating substrates supported only localized corrosion.

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33

Williamson, Joanne. "The influence of concrete cover properties on the effects of reinforcement corrosion." Thesis, University of Birmingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496284.

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34

Chevrot, Thierry. "Pressure effects on the hot-salt stress-corrosion cracking of titanium alloys." Thesis, Cranfield University, 1994. http://dspace.lib.cranfield.ac.uk/handle/1826/7745.

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Benefiting from good specific mechanical properties, exceptional oxidation resistance, and high temperature capability, Titanium Alloys are used in Gas Turbine Engines, especially in the early stages of the compressor. However they are subject to stresscorrosion cracking in the laboratory when subjected to stresses and contaminated with salts at elevated temperatures. The lack of in-service failures of titanium components due to Hot-Salt Stress-Corrosion Cracking (HSSCC) is not yet understood. The parameters influencing the HSSCC of titanium alloys (temperature, load, stress and temperature cycling, quantity and kind of salt, air velocity, water vapour or oxygen content of the atmosphere, composition, texture, and microstructure of the alloy, surtace conditions), cannot account for the lack of in-service failure. After an examination of the service conditions within a typical gas turbine engine compressor, it was considered that the high pressures prevailing may extend the life of titanium alloys subjected to HSSCC. This work used a unique high temperature, high pressure, servo-hydraulic facility in order to carry out hot-salt stress-corrosion testing on titanium alloy 1M! 834 at high pressure. The results obtained show that high oxygen partial pressures extend significantly the life of 1M! 834 subjected to HSSCC. Continuous thermogravimetric measurements both in oxidising and salt-corroding environments were carried out to study the kinetics of the hot-salt attack of IMI 834. Basic metallography revealed the formation of channels which extend deep into the metal during the initial stages of hot-salt-corrosion. Theoretical thermodynamic studies highlighted the role of alloying elements and vapour phase metallic chlorides in the mechanisms of the HSSCC of titanium alloys. A new model for the hot-salt stress-corrosion of titanium alloys is proposed. It is based on the establishment of a self sustaining cycle where vapour phase metallic chlorides act as hydrogen carriers and can diffuse quickly into the material through channels.

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Li, Wei. "Mechanical Effects of Flow on CO2 Corrosion Inhibition of Carbon Steel Pipelines." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1461751721.

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36

Theron, Gavin De Vos. "Effects of reinforcement corrosion on the structural performance of reinforced concrete beams." Master's thesis, University of Cape Town, 1994. http://hdl.handle.net/11427/18238.

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This dissertation is an investigation into the effect of reinforcement corrosion on the structural performance of reinforced concrete beams. Two types of specimens are investigated, the first without any stirrups and the second with stirrups. The specimens were corroded galvanostatically as well as by subjecting them to alternate cycles of wetting and drying with a saline water. An attempt is made at classifying the extent of corrosion of the reinforcing steel and its effects on the concrete. The effect of the corrosion on the structural performance is measured by establishing its effect on the maximum load carrying capacity, the deflections, energy requirements and ductility ratio. The main conclusions made in respect of the effect of reinforcement corrosion are that it causes: a decrease in the load carrying capacity; an increase in the deflections at the equivalent load level; a decrease in the energy requirements to reach the maximum load; and a smoothing of the load-deflection relationship. A limited literature review is also presented to provide background information of corrosion in concrete and general structural behaviour. Guidelines for the development of an analytical model to predict the load carrying capacity of corrosion affected reinforced concrete beams are also given.

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37

Mhaede, Saad Mansour Hamed. "Corrosion performance of high strength aluminum alloys-effects of mechanical surface treatments." Clausthal-Zellerfeld Papierflieger, 2008. http://d-nb.info/996419667/04.

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38

Gaydos, Peter Andrew. "The effects of load and humidity on friction and life of polymeric coatings used to prevent fretting corrosion." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/53123.

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A statistical analysis was conducted to investigate the effect of applied load and relative humidity of the atmosphere on the durability and coefficient of friction of five polymer coatings used to protect against fretting corrosion. Chlorine and non-chlorine containing polymers were used in this research to see if the large humidity effect seen in a previous study with polyvinyl chloride is strictly a chlorine related phenomenon. The five polymers used were polyvinyl chloride, polyvinylidene chloride, polystyrene, and two siloxane modified polyimides. Disks made of 1045 steel were coated with thin polymeric films and fretted against a 52100 steel ball. Three levels of load were used: 11.12, 22.25, and 44.5 N, and the two levels of relative humidity were less than 10% and between 45 and 55%. Amplitude of oscillation was 330 μm peak to peak, frequency of oscillation was 40 Hz, and the coating thickness was 25 μm. Statistically significant variables and interactions are identified, and reasons for their significance are discussed. Increasing the humidity had no consistent effect on the ending coefficient of friction between the polymer film and the oscillating ball, increasing the load decreased the coefficient of friction, and either increasing the humidity or load decreased the life of the coating during fretting. The extent of this reduction in life depends on the polymer. The relative humidity of the environment affected the coating life of only one of the chlorine-containing polymers. Humidity was also shown to affect the coating life of two polymers that do not contain chlorine.
Master of Science

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39

Hazzaa, M. I. "Synergistic effects in the inhibition by chromate-containing mixtures of the corrosion of mild steel." Thesis, University of Manchester, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380533.

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40

Kashyap, Anusha Venkitachalam. "Effects of water chemistry, temperature, gaseous cavitation & phosphate inhibitors on concrete corrosion." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/35788.

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Concrete corrosion has serious societal and economic impacts and is an important concern in a utilityâ s overall corrosion control strategy. Though concrete based pipes and linings are only restricted to the distribution mains, they still make up a large percentage of the drinking water infrastructure at about 17% of its total length. An improved understanding of the corrosion mechanisms involved steps that can be taken to mitigate concrete corrosion are very important. This study examined the role of phosphate chemicals, water chemistry, temperature and gaseous cavitation on the degradation of cement-based pipes and linings. It also provides information for utilities to make informed decisions regarding the use, effectiveness, and application of phosphate corrosion inhibitors relative to concrete corrosion control.

Under low alkalinity and low pH conditions, considered to be highly aggressive in the literature, we noticed very substantial corrosion of concrete in laboratory experiments. At high pH and high alkalinity conditions, the buildup of scale (e.g., calcium carbonate) on the inside of the pipe is the major concern. The addition of phosphate inhibitors strongly influenced both concrete corrosion and scaling. At low alkalinity the addition of zinc orthophosphate or polyphosphate reduced corrosion of concrete. The addition of orthophosphate under low alkalinity conditions increased aluminum leaching and could push aluminum concentrations above the EPA SMCL threshold. At high alkalinity conditions the addition of orthophosphate is highly effective at reducing scaling, and aluminum leaching was not a concern.

The presence of high concentrations of magnesium and silicon could form magnesium aluminum oxyhydroxides and magnesium silicates which could act as a protective scale on the concrete surface. However, this precipitate forms only at pH values above 9.5. The effectiveness of this protective scale in reducing corrosion of concrete was not established unambiguously in this research. Temperature plays a key role in corrosion of concrete. Calcite solubility increases at lower temperatures however at higher temperatures corrosion of concrete increases, which implies that corrosion of concrete is not driven by calcite solubility. At higher alkalinities scaling of concrete is higher at lower temperatures. This indicates that calcite solubility controls scaling of concrete at higher alkalinities. Tests with gaseous cavitation indicate that corrosion of concrete does not increase in the presence of gaseous cavitation. Vaporous cavitation is more detrimental to concrete than gaseous cavitation.

Master of Science

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41

Yang, Qi. "Effects of hydrogen on passivity and corrosion related behavior of austenitic stainless steels." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0010/NQ59701.pdf.

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42

Guo, Yanling [Verfasser]. "The Effects of Minor Constituents on Corrosion of Zirconia by Steel / Yanling Guo." Aachen : Shaker, 2005. http://d-nb.info/1186587954/34.

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43

Wasserstrom, Lauren W. "Uptake of Lead by Iron Corrosion Scales: Effects of Iron Mineralogy and Orthophosphate." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1396524188.

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44

Cohen, Laura Jane Rachel. "Some effects of hydrogen on duplex stainless steels." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292256.

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45

Porr, William C. "Specimen size effects in slow strain-rate testing." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/53153.

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A study was conducted to evaluate the effect of specimen dimensions in slow strain-rate environmental effects testing. Tension tests of free machining brass were conducted in a mercuric nitrate solution at a constant crosshead displacement rate of 10⁻³(inch/sec). Thirty-six smooth round bar specimens with different dimensions were tested. It was shown that percent elongation to failure was inversely proportional to an effective ratio of length to diameter, ((D - 2a)L / D²), where D is the specimen diameter, L is the length of the reduced cross section of the specimen, and a is the environmentally induced crack depth. This effective length to diameter ratio correlates with the applied tearing modulus for a cracked round bar tension specimen as defined by P. C. Paris and co-workers in 1979. The results verify that the tearing modulus may be used as a parameter to evaluate tearing instability in terms of elastic-plastic fracture mechanics. More directly, these results show a possible source of error in evaluating the degree of susceptibility to environmentally induced cracking in a material-environment interaction.
Master of Science

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Wang, Kai Yuan. "Effects of metallurgical variables on the cavitation erosion behaviour of wrought austenitic stainless steel." Thesis, University of Macau, 2017. http://umaclib3.umac.mo/record=b3691143.

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Li, Jing Hui. "Effects of metallurgical variables on the cavitation erosion behaviour of AISI 304 austenitic stainless steel." Thesis, University of Macau, 2017. http://umaclib3.umac.mo/record=b3691682.

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Lim, Chwee-Teck. "Effects of compliance and friction on elastic-plastic impact." Thesis, University of Cambridge, 1996. https://www.repository.cam.ac.uk/handle/1810/273133.

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Xie, Tieling. "Electrochemical corrosion effects of ethanol based fuel on general aviation aircraft fuel system components." Diss., Mississippi State : Mississippi State University, 2004. http://library.msstate.edu/etd/show.asp?etd=etd-11072004-122317.

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Talukdar, Sudip. "The effects of global climate change on carbonation induced corrosion of reinforced concrete structures." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44259.

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Abstract:

There is nearly unanimous consensus amongst scientists that increasing greenhouse gas emissions, including CO₂ generated by human activity, are affecting the Earth‘s climate. Climate change has the potential to overwhelm existing capacities, as well as durability of concrete infrastructure. Carbonation of concrete occurs due to a reaction between atmospheric CO₂ and the hydrated phases of concrete, leading to a drop in its pH and the depassivation of embedded rebar. Therefore, increases in carbonation rates of reinforced concrete structures are expected as a result of increased temperatures and CO₂ concentrations, with the enhanced risk of carbonation induced corrosion likely affecting the longevity of our concrete infrastructure. This thesis considered the potential consiquences of global climate change on our concrete infrastructure, with the objective being to determine if there is an increased risk of deterioration due to carbonation induced corrosion. A unique numerical model was developed to determine carbonation rates in structures, and verified through experimental tests. The model was applied to a number of cities in locations throughout the world to determine where structures were most vulnerable. Additionally, a number of other laboratory experiments were carried out to supplement the numerical model and provide insights as to how carbonation progress can be monitored within a structure. Using the model developed, and inputting forecasts for increases in future atmospheric CO₂ concentrations and weather conditions, it was shown that for medium quality, non-pozzolonic concrete in geographic areas where carbonation induced corrosion is a concern, global climate change will affect its progress in our concrete infrastructure. We will see much higher ultimate carbonation depths in the long term. The use of non-destructive testing (NDT) methods, and structural health monitoring (SHM) techniques could be invaluable in monitoring the progress of carbonation in a structure, but the data generated by the methods and techniques used must be analyzed carefully before making any conclusions. For the NDT methods and carbonation pH sensors which were evaluated in this study, it was found that ambient test conditions had a major impact on results.

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Dissertations / Theses on the topic 'Corrosion effects'

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