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Sample records for comparative corrosion study

  1. Electrochemical corrosion studies

    Science.gov (United States)

    Knockemus, W. W.

    1986-01-01

    The objective was to gain familiarity with the Model 350 Corrosion Measurement Console, to determine if metal protection by grease coatings can be measured by the polarization-resistance method, and to compare corrosion rates of 4130 steel coated with various greases. Results show that grease protection of steel may be determined electrochemically. Studies were also conducted to determine the effectiveness of certain corrosion inhibitors on aluminum and steel.

  2. Comparative corrosion study of Ag–Pd and Co–Cr alloys used in dental applications

    Indian Academy of Sciences (India)

    D Mareci; D Sutiman; A Cailean; G Bolat

    2010-08-01

    The electrochemical behaviour of two Ag–Pd alloys (Unique White and Paliag) used in dental prosthetics construction for crowns and bridges and one Co–Cr alloy (Vitallium 2000) was studied in artificial saliva using the polarization curves and electrochemical impedance spectroscopy (EIS). The corrosion resistance was evaluated by means of the corrosion currents value and by coulometric analysis. The open circuit potential of Ag–Pd are attributed to dealloying followed by surface enrichment with Ag and the possible formation of an insoluble AgCl surface film on the respective alloy surfaces. Our results have shown that these alloys have a somewhat good corrosion resistance in artificial saliva. The corrosion current densities of Unique White and Vitallium 2000 alloys were very low (∼100 nA/cm2). For Ag–Pd alloys, when increasing the content of Cu, corrosion resistance decreases. The passivation of all samples occurred spontaneously at the open circuit potential. The electrochemical properties of the spontaneously passivated electrodes at the open circuit potential were studied by EIS. The polarization resistance (p) and the electrode capacitance (dl) were determined. The polarization resistance of all the samples increases with the immersion time. The polarization resistances are largest for Unique White (Ag–Pd) and Vitallium 2000 (Co–Cr) alloys. Because the electrochemical behaviour of the Co–Cr alloy was compared with that of Ag–Pd alloy, this type of alloy may be a suitable alternative for use in the manufacture of fixed dental prostheses. The present study, though limited, has shown that electrochemical characteristics can be used to identify such alloys. Knowledge of the in vitro corrosion behaviour of these alloys may lead to better understanding of any biologically adverse effects in vitro.

  3. A comparative study of the corrosion resistance of incoloy MA 956 and PM 2000 superalloys

    Directory of Open Access Journals (Sweden)

    Maysa Terada

    2010-12-01

    Full Text Available Austenitic stainless steels, titanium and cobalt alloys are widely used as biomaterials. However, new medical devices require innovative materials with specific properties, depending on their application. The magnetic properties are among the properties of interest for some biomedical applications. However, due to the interaction of magnetic materials with Magnetic Resonance Image equipments they might used only as not fixed implants or for medical devices. The ferromagnetic superalloys, Incoloy MA 956 and PM 2000, produced by mechanical alloying, have similar chemical composition, high corrosion resistance and are used in high temperature applications. In this study, the corrosion resistance of these two ferritic superalloys was compared in a phosphate buffer solution. The electrochemical results showed that both superalloys are passive in this solution and the PM 2000 present a more protective passive film on it associated to higher impedances than the MA 956.

  4. COMPARATIVE STUDY OF THE CORROSION BEHAVIOR OF HOT DIP GALVANIZED, GALVANNEAL AND GALVALUME COATED STEELS

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    Álvaro Pritzel dos Santos

    2013-10-01

    Full Text Available Corrosion attack of Hot Dip Zn coatings on steels is comparatively studied. For this, the electrochemical behavior of the coatings hot dip galvanized (GI, galvanneal (GA and galvalume (Zn55Al are analyzed in chloride solutions by cyclic voltammetry and by Scanning Vibrating Electrode Technique, with and without the incidence of white light. Coatings were characterized by Scanning Electronic Microscopy and Energy Dispersive X-Ray Spectrometry. The results show that the incidence of white UV-VIS light has a minor influence on the corrosive process, although the coatings contain intermetallic phases with semiconductor nature. The tests show that among the three coatings, GA has the slowest dissolution rate, when in contact with the steel for high exposed areas of steel.

  5. Corrosion Inhibition Study of Mild Steel in Acidic Medium by Antibiotic Drugs: A Comparative Study

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    Md. A. Aziz

    2014-04-01

    Full Text Available A comparison of the inhibiting efficiency of antibiotic drugs (ciprofloxacin, cloxacillin, and amoxicillin on the corrosion of mild steel in 1 mol·L−1 HCl were studied at room temperature using mass loss measurement. The main reason is probably be due to the formation of protective coverage by the inhibitor as other authors reported previously. Adsorption characteristics of the inhibitor has also been studied using simple equation and it was found that drugs inhibits the corrosion of mild steel by being adsorbed on the surface of mild steel by a physical adsorption mechanism. The adsorption of drugs on the mild steel surface was found to be spontaneous and obey the Langmuir adsorption isotherm model. It was observed that the test drug has a promising inhibitory action in acid medium against corrosion of mild steel. Moreover it was revealed that an inhibition efficiency of 80.1 % can be achieved with 3×10-3M ciprofloxacin drug treatment on mild steel.

  6. Comparative study of the corrosion product films formed in biotic and abiotic media

    Energy Technology Data Exchange (ETDEWEB)

    Videla, H.A.; Mele, M.F.L. de [Univ. of La Plata (Argentina). Dept. of Chemistry; Swords, C. [Univ. of Leeds (United Kingdom). School of Materials; Edyvean, R.G.J. [Univ. of Sheffield (United Kingdom). Dept. of Chemical and Processing Engineering; Beech, I.B. [Univ. of Portsmouth (United Kingdom). Dept. of Chemistry

    1999-11-01

    The growth of sulfate-reducing bacteria (SRB) affects several important parameters at the metal/solution interface of carbon steel in liquid media such as pH and redox potential values, as well as modifications of the composition and structure of corrosion product layers. Electrochemical techniques for corrosion assessment and surface analyses by energy dispersion X-ray analysis (EDAX), X-ray photoelectron spectra (XPS), X-ray distraction (XRD) and electron microprobe analysis (EPMA) complemented with scanning electron microscopy (SEM) and atomic force microscopy (MM) observations, were used to study the structure and composition of protective films on carbon steel in abiotic and biotic media containing different sulfur anions. The results revealed that in biotic and abiotic sulfide films the outer layers were formed by both FeS and FeS{sub 2}, although the relative content of these compounds varied in each case. Usually, the corrosion product films biotically formed were more adherent to the metal surface than those developed abiotically. The latter were flaky and loosely adherent, thus differing in their function during the corrosion process.

  7. Comparative study of the corrosion behavior of peripheral stents in an accelerated corrosion model: experimental in vitro study of 28 metallic vascular endoprostheses.

    Science.gov (United States)

    Paprottka, Karolin J; Paprottka, Philipp M; Reiser, Maximilian F; Waggershauser, Tobias

    2015-01-01

    Clinical cases of stent-fractures show that corrosion behavior might play a role in these fractures. Implanted in vivo, especially in combination with other implanted foreign materials, these metallic products are exposed to special conditions, which can cause a process of corrosion. Here, we aimed to test the corrosion potential of stents made of different materials in an in vitro setting. A total of 28 peripheral stents of different materials (nitinol, cobalt-chromium-nickel, tantalum, V4A) and surface treatments (electropolish, mechanical polish, no polish) were tested in vitro. Corrosion was accelerated by applying a constant voltage of 3.5 V and amperage of 1.16 mA in 0.9% NaCl. Nitinol stents showed the lowest susceptibility to corrosion and the longest period without damage. The Memotherm II® (BARD Angiomed®) was the only stent that showed neither macroscopic nor microscopic damages. The worst performing material was cobalt-chromium-nickel, which showed corrosion damages about ten times earlier compared to nitinol. Considering the reasons for termination of the test, nitinol stents primarily showed length deficits, while V4A and tantalum stents showed fractures. Cobalt-chromium-nickel stents had multiple fractures or a complete lysis in equal proportions. When placed in direct contact, nitinol stents showed best corrosion resistance, regardless of what material they were combined with. In terms of polishing treatments, electropolished stents performed the best, mechanical-polished stents and those without polishing treatment followed. The analysis of corrosion behavior may be useful to select the right stent fulfilling the individual needs of the patient within a large number of different stents.

  8. Comparative Study of Elaeis Guiniensis Exudates (Palm Wine as a Corrosion Inhibitor for Mild Steel in Acidic and Basic Solutions

    Directory of Open Access Journals (Sweden)

    S.C. Nwigbo

    2012-01-01

    Full Text Available This study has explored the possibility of using a typical plant extract other than the use of conventional materials as corrosion inhibitor. Elaeis guinensis exudates (Palm wine, which contains carbonyl groups, double bonds and triple bonds as shown by the FTIR, Gas chromatography-mass spectrometry and phytochemical tests is a one of good natural materials as corrosion inhibitor. This paper was focused on the behaviour of palm wine as corrosion inhibitor for mild steel in (0.1 and 0.5 M H2SO4 and NaOH solutions at 303 and 333 K temperatures and inhibitor concentrations using weight loss measurement. Results showed that weight loss decreases as concentration of both solutions studied increase. The inhibitor performs better under the basic solution compared to the acidic solution. The kinetics results showed that activation energy increases as temperature and inhibitors concentration increase. Palm wine inhibitor adsorbed on the surface of mild steel through physical adsorption.

  9. A Comparative Study on Ni-Based Coatings Prepared by HVAF, HVOF, and APS Methods for Corrosion Protection Applications

    Science.gov (United States)

    Sadeghimeresht, E.; Markocsan, N.; Nylén, P.

    2016-12-01

    Selection of the thermal spray process is the most important step toward a proper coating solution for a given application as important coating characteristics such as adhesion and microstructure are highly dependent on it. In the present work, a process-microstructure-properties-performance correlation study was performed in order to figure out the main characteristics and corrosion performance of the coatings produced by different thermal spray techniques such as high-velocity air fuel (HVAF), high-velocity oxy fuel (HVOF), and atmospheric plasma spraying (APS). Previously optimized HVOF and APS process parameters were used to deposit Ni, NiCr, and NiAl coatings and compare with HVAF-sprayed coatings with randomly selected process parameters. As the HVAF process presented the best coating characteristics and corrosion behavior, few process parameters such as feed rate and standoff distance (SoD) were investigated to systematically optimize the HVAF coatings in terms of low porosity and high corrosion resistance. The Ni and NiAl coatings with lower porosity and better corrosion behavior were obtained at an average SoD of 300 mm and feed rate of 150 g/min. The NiCr coating sprayed at a SoD of 250 mm and feed rate of 75 g/min showed the highest corrosion resistance among all investigated samples.

  10. A Comparative Study on Corrosion Inhibition of Mild Steel Using Piper Nigrum L. in Different Acid Medium

    OpenAIRE

    Anand, B.; Balasubramanian, V

    2010-01-01

    The inhibition of corrosion of mild steel using Piper nigrum L in different acid medium by weight loss method was investigated. The corrosion inhibition was studied in hydrochloric acid and sulphuric acid by weight loss method at different time interval at room temperature. The result showed that the corrosion inhibition efficiency of this compound was found to vary with different time interval and different acid concentration. Also, it was found that the corrosion inhibition behavior of Pipe...

  11. A Comparative Study on Corrosion Inhibition of Mild Steel Using Piper Nigrum L. in Different Acid Medium

    Directory of Open Access Journals (Sweden)

    B. Anand

    2010-01-01

    Full Text Available The inhibition of corrosion of mild steel using Piper nigrum L in different acid medium by weight loss method was investigated. The corrosion inhibition was studied in hydrochloric acid and sulphuric acid by weight loss method at different time interval at room temperature. The result showed that the corrosion inhibition efficiency of this compound was found to vary with different time interval and different acid concentration. Also, it was found that the corrosion inhibition behavior of Piper nigrum L is greater in sulphuric acid than hydrochloric acid. So, Piper nigrum L can be used as a good inhibitor for preventing mild steel material.

  12. Comparative study of formation and corrosion performance of porous alumina and ceramic nanorods formed in different electrolytes by anodization

    Energy Technology Data Exchange (ETDEWEB)

    Raj, V., E-mail: alaguraj2@rediffmail.com; Mumjitha, M., E-mail: mumjitha@gmail.com

    2014-01-15

    Highlights: • Alumina–titania coatings were fabricated by anodization in a single step. • The universal and cheap sulphuric acid was used as the reference electrolyte. • The minimum concentration of PTO is used to achieve ceramic nanorods. • Dense ceramic coatings were achieved at low current density and room temperature. • Anodized coatings show better corrosion resistance compared to bare aluminium. -- Abstract: Fabrication of Al{sub 2}O{sub 3}–TiO{sub 2} nanoceramic coatings on aluminium was carried out in a single step using cost effective sulphuric acid electrolyte with the addition of potassium titanium oxalate (PTO) by anodization method. For comparison, the anodization was also carried out in sulphuric acid electrolyte alone. The effect of composition of the electrolyte, current density and electrolyte concentration on formation and surface characteristics of anodic alumina and ceramic coatings produced from different electrolytes have been investigated. The growth process, surface morphology, nanostructure, distribution of chemical elements, phase constitutions and corrosion resistance of the coatings formed in two different electrolytes were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Tafel polarization technique and electrochemical impedance spectroscopy (EIS). As the concentration of electrolyte and current density increased, the surface properties of the coating increased up to certain content and beyond that they decreased. Dense, uniform nanoceramic coatings with less surface defects were obtained from sulphuric acid + PTO electrolyte. The corrosion studies reveal that ceramic coating formed in sulphuric acid + PTO electrolyte offers better corrosion resistance compared to the alumina coating formed in sulphuric acid electrolyte.

  13. Comparative study on lithium borates as corrosion inhibitors of aluminum current collector in lithium bis(fluorosulfonyl)imide electrolytes

    Science.gov (United States)

    Park, Kisung; Yu, Sunghun; Lee, Chulhaeng; Lee, Hochun

    2015-11-01

    Lithium bis(fluorosulfonyl)imide (LiFSI) is a promising salt that can possibly overcome the limitations of lithium hexafluorophosphate (LiPF6) in current Li-ion batteries (LIBs). Aluminum (Al) corrosion issue, however, is a major bottleneck for the wide use of LiFSI. This study investigates lithium borate salts as Al corrosion inhibitors in LiFSI electrolytes. Through a systematic comparison among lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), and lithium difluoro(oxalato)borate (LiDFOB), and LiPF6, the inhibition ability of the additives is revealed to be in the following order: LiDFOB > LiBF4 ≈ LiPF6 > LiBOB. In particular, the inhibition effect of LiDFOB is outstanding; the anodic behavior of Al in 0.8 M LiFSI + 0.2 M LiDFOB ethylene carbonate (EC)-based electrolyte is comparable to that of corrosion-free 1 M LiPF6 solution. The superior inhibition ability of LiDFOB is attributed to the formation of a passive layer composed of Al-F, Al2O3, and B-O species, as evidenced by X-ray photoelectron spectroscopy (XPS) measurements. A LiCoO2/graphite cell with 0.8 M LiFSI + 0.2 M LiDFOB electrolyte exhibits a rate capability comparable to a cell with 1 M LiPF6 solution, whereas a cell with 0.8 M LiFSI solution without LiDFOB suffers from poor power performance resulting from severe Al corrosion.

  14. A comparative study of the corrosion of wire used in urological treatment under sterilization

    Directory of Open Access Journals (Sweden)

    W. Walke

    2012-04-01

    Full Text Available The purpose of the tests was to determine whether and how sterilization process of samples made of AISI 316L stainless steel with different strain impacts their corrosion resistance. Tests were made on steel samples that had been electrochemically polished in order to assure proper surface roughness. In order to evaluate the influence of sterilization on physical and chemical properties of steel surface, tests of corrosion resistance were made by means of potentiodynamical method. The tests were made in alternative solution simulating human urine. Recorded anodic polarization curves created the ground for determination of typical parameters describing pitting corrosion resistance, that enabled to evaluate steel wire corrosion behavior under sterilization conditions.

  15. Comparative study on structure, corrosion and hardness of Zn-Ni alloy deposition on AISI 347 steel aircraft material

    Energy Technology Data Exchange (ETDEWEB)

    Gnanamuthu, RM. [Department of Chemical Engineering, College of Engineering, Kyung Hee University, 1732 Deogyeong-daero, Gihung, Yongin, Gyeonggi 446-701 (Korea, Republic of); Mohan, S., E-mail: sanjnamohan@yahoo.com [Central Electrochemical Research Institute, (CSIR), Karaikudi 630 006, Tamilnadu (India); Saravanan, G. [Central Electrochemical Research Institute, (CSIR), Karaikudi 630 006, Tamilnadu (India); Lee, Chang Woo, E-mail: cwlee@khu.ac.kr [Department of Chemical Engineering, College of Engineering, Kyung Hee University, 1732 Deogyeong-daero, Gihung, Yongin, Gyeonggi 446-701 (Korea, Republic of)

    2012-02-05

    Highlights: Black-Right-Pointing-Pointer Electrodeposition of Zn-Ni alloy on AISI 347 steel as an aircraft material has been carried out from various baths. Black-Right-Pointing-Pointer The effect of pulse duty cycle on thickness, current efficiency and hardness reached maximum values at 40% duty cycle and for 50 Hz frequencies average current density of 4 A dm{sup -2}. Black-Right-Pointing-Pointer The XRF characterizations of 88:12% Zn-Ni alloy provided excellent corrosion resistance. Black-Right-Pointing-Pointer It is found that Zn-Ni alloy on AISI 347 aircraft material has better structure and corrosion resistance by pulse electrodeposits from electrolyte-4. - Abstract: Zn-Ni alloys were electrodeposited on AISI 347 steel aircraft materials from various electrolytes under direct current (DCD) and pulsed electrodepositing (PED) techniques. The effects of pulse duty cycle on thickness, current efficiency and hardness of electrodeposits were studied. Alloy phases of the Zn-Ni were indexed by X-ray diffraction (XRD) techniques. Microstructural morphology, topography and elemental compositions were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray fluorescence spectroscopy (XRF). The corrosion resistance properties of electrodeposited Zn-Ni alloy in 3.5% NaCl aqueous solution obtained by DCD and PED were compared using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) technique. Elemental analysis showed that 88% of Zn and 12% of Ni obtained from electrolyte-4 by PED technique at 40% duty cycle for 50 Hz frequencies having better corrosion resistance than that of deposits obtained from other electrolytes.

  16. Comparative Study by Electrochemical Impedance Spectroscopy (EIS On The Corrosion Resistance of Industrial and Laboratory Zinc Coatings

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    Y. Hamlaoui

    2007-01-01

    Full Text Available In this work, corrosion monitoring of Zn-based coatings is investigated through potentiodynamic and electrochemical impedance spectroscopy (EIS methods. The first part of the study is devoted to galvanised coatings conventionally manufactured in the industry. The second part focuses on the corrosion resistance of a laboratory-made electrolytic coating. For such purpose, the corrosion behaviour is studied in NaCl media under various conditions. The results show that EIS allows to establish the interfacial reactions and the dissolution mechanisms occurring in this media, hence to foresee the protection conferred by these coatings. Moreover, the salted media at different concentrations allow to unambiguously assess the coating quality in terms of porosity. However, others corrosive media can reveal the slowest reaction without having appeal to a very low frenquency scanning. Finally, Zn/NaCl interface is characterised by a specific equivalent circuit giving a similar impedance response.

  17. A comparative study of the cytotoxicity and corrosion resistance of nickel-titanium and titanium-niobium shape memory alloys.

    Science.gov (United States)

    McMahon, Rebecca E; Ma, Ji; Verkhoturov, Stanislav V; Munoz-Pinto, Dany; Karaman, Ibrahim; Rubitschek, Felix; Maier, Hans J; Hahn, Mariah S

    2012-07-01

    Nickel-titanium (NiTi) shape memory alloys (SMAs) are commonly used in a range of biomedical applications. However, concerns exist regarding their use in certain biomedical scenarios due to the known toxicity of Ni and conflicting reports of NiTi corrosion resistance, particularly under dynamic loading. Titanium-niobium (TiNb) SMAs have recently been proposed as an alternative to NiTi SMAs due to the biocompatibility of both constituents, the ability of both Ti and Nb to form protective surface oxides, and their superior workability. However, several properties critical to the use of TiNb SMAs in biomedical applications have not been systematically explored in comparison with NiTi SMAs. These properties include cytocompatibility, corrosion resistance, and alterations in alloy surface composition in response to prolonged exposure to physiological solutions. Therefore, the goal of the present work was to comparatively investigate these aspects of NiTi (49.2 at.% Ti) and TiNb (26 at.% Nb) SMAs. The results from the current studies indicate that TiNb SMAs are less cytotoxic than NiTi SMAs, at least under static culture conditions. This increased TiNb cytocompatibility was correlated with reduced ion release as well as with increased corrosion resistance according to potentio-dynamic tests. Measurements of the surface composition of samples exposed to cell culture medium further supported the reduced ion release observed from TiNb relative to NiTi SMAs. Alloy composition depth profiles also suggested the formation of calcium phosphate deposits within the surface oxide layers of medium-exposed NiTi but not of TiNb. Collectively, the present results indicate that TiNb SMAs may be promising alternatives to NiTi for certain biomedical applications. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  18. Electrochemical noise evaluation of anodized aluminum. Comparative study against corrosion behaviour in the atmosphere

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    Betancourt, N.

    2003-12-01

    Full Text Available The present work reports the evaluation of aluminum and anodized aluminum by electrochemical noise, as a part of the PATINA/CYTED project of the working group Nº 5. A visual examination is also made. The samples were exposed at several Ibero-American atmospheres up to 2 years of exposure. Different thickness of anodized aluminum were evaluated. The electrochemical potential noise of the 5 μm unexposed sample (pattern showed a different behaviour to that showed by the other anodized specimens. This could be due to a slower sealed of the samples of higher thickness. The same behaviour was observed on the samples exposed at the rural station El Pardo. According to the visual examination, the samples of bare aluminum and those of anodized 5 μm thickness were the most affected by pitting corrosion in the highly polluted atmospheres. A good correlation between corrosion behaviour determined by visual examination and EN was obtained.

    Como parte de las investigaciones de la Red PATINA el grupo de trabajo Nº 5 dedicó su atención al comportamiento del aluminio desnudo y anodizado con diferentes espesores en diferentes atmósferas de Iberoamérica. En el presente trabajo se presenta una evaluación de patrones de aluminio 99,5 % de pureza desnudo y anodizado con espesores de 15 y 25 μm, mediante ruido electroquímico. Los resultados obtenidos se comparan con el comportamiento determinado en diferentes atmósferas durante un período de 2 años. El ruido de voltaje del patrón de 5 μm de espesor presenta un comportamiento diferente al de los restantes espesores, lo que coincide con una mayor susceptibilidad a la corrosión picadura de este primer anodizado. Se reportan también algunas diferencias en el ruido de corriente. Se concluye que mediante la utilización del ruido electroquímico es posible caracterizar el aluminio con respecto a su sensibilidad a la corrosión picadura en condiciones atmosféricas.

  19. A Comparative Corrosion Study of Al/Al2O3-SiC Hybrid Composite Fabricated by Accumulative Roll Bonding (ARB

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    Mohsen Reihanian

    2016-06-01

    Full Text Available In this study, the Al/Al2O3-SiC hybrid composite was produced by accumulative roll bonding (ARB. In the first and the second cycles, the particles were uniformly poured between the Al strips during each ARB cycle. In the subsequent cycles, ARB was repeated up to six cycles without adding the particles between the layers. After the total eight cycles, the particles were distributed uniformly without agglomeration in the Al matrix. The corrosion behavior of the hybrid composite was investigated and compared with that of the annealed and ARB processed Al. The corrosion tests were conducted by the potentiodynamic and electrochemical impedance spectroscopy tests in 3.5 wt-% NaCl solution. The anodic potential of the pure Al processed by ARB was more positive than that of the annealed Al while its corrosion current density was higher. The corrosion potential of the hybrid composite was somewhere between the annealed Al and ARB processed Al. The hybrid composite exhibited the lowest current density and the highest charge transfer resistance. The increased corrosion resistance of the hybrid composite was attributed to the inert character of the Al2O3 and SiC particles because these particles could decrease the active sites of the material surface and impeding the corrosive attacks.

  20. A comparative study of the corrosion performance of TiN, Ti(B,N) and (Ti,Al)N coatings produced by physical vapour deposition methods

    Energy Technology Data Exchange (ETDEWEB)

    Aromaa, J.; Ronkainen, H.; Mahiout, A.; Hannula, S.P. (Technical Research Centre of Finland, Espoo (Finland)); Leyland, A.; Matthews, A. (Univ. of Hull (United Kingdom)); Matthes, B.; Broszeit, E. (Technische Hochschule Darmstadt (Germany))

    1991-07-07

    Thin film coatings produced by physical vapour deposition methods often exhibit porosity. Local defects can cause local and rapid corrosion of the base material. The porosity is difficult to estimate and electrochemical methods are most suitable for evaluating the corrosion resistance of the coated material. This paper compares the corrosion resistance of TiN, Ti(B,N), (Ti,Al)N- and TiB{sub 2}-coated ASP 23 high speed steel. For the materials studied here the corrosion performance of TiB{sub 2}-coated samples was poor. Ti(B,N) coatings obtained by two different methods were quite similar even though the calculated porosity of the coating produced by magnetron sputtering was lower than that of coatings produced by the electron beam technique. These coatings had similar or slightly better corrosion resistance than (Ti,Al)N coatings with a high aluminium-to-titanium ratio. (Ti,Al)N coatings with a low aluminium-to-titanium ratio were better than coatings with a high aluminium-to-titanium ratio. TiN coatings were better than other types excluding (Ti,Al)N+AlN layer coatings, which performed best. (Ti,Al)N+AlN coatings have an insulating layer on top of the coating, which increases the polarization resistance and decreases the corrosion current density. (orig.).

  1. Avionics Corrosion Control Study

    Science.gov (United States)

    1974-01-01

    found at seacoast (harsn) environnents is the most destructive. Differences in electrolte concentration and oxygen concentration promote corrosion...against corrosion by acting as moisture and gas barriers. CMCVIT B0.4ID *COATINGS Polyurethane’s, cprxies, silicones, and polystyrenes are the most

  2. A Comparative Study on causes of corrosion of steel reinforcement in RC structures at Bangalore, India and Kigali, Rwanda

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    Abaho G

    2015-06-01

    Full Text Available Premature failure of reinforced concrete structures occurs primarily due to early corrosion of steel reinforcement. This paper intends to uplift the awareness of people about the role of structure maintenance to prevent or control corrosion in steel reinforced concrete structures. Some data collected using a designed questionnaire were distributed in Bangalore, India and Kigali, Rwanda, about corrosion of steel reinforcement which actually motivated this research. The research finds that without corrosion in steel reinforced concrete structures is just a matter of time. However corrosion map for Kigali is not available. Hence the survey has been conducted in Rwanda. Based on survey corrosion map will be prepared so that vulnerable areas for corrosion can be identified. This map will enable for protective design of structures against corrosion. The new steel RC structures corrosion monitoring systems should be incorporated for future less costly, timely maintenance for their reliable service life.

  3. A Comparative Study of the Inhibitory Effect of Gum Exudates from Khaya senegalensis and Albizia ferruginea on the Corrosion of Mild Steel in Hydrochloric Acid Medium

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    Paul Ocheje Ameh

    2015-01-01

    Full Text Available A comparative study of the inhibitory potentials of gum exudates from Albizia ferruginea (AF and Khaya senegalensis (KS on the corrosion of mild steel in HCl medium was investigated using weight loss and gasometric method. The active chemical constituents of the gum were elucidated using GC-MS while FTIR was used to identify the bonds/functional groups in the gums. The two gum exudates were found to be good corrosion inhibitors for mild steel in acidic medium. On comparison, maximum inhibition efficiency was found in Khaya senegalensis with 82.56% inhibition efficiency at 0.5% g/L concentration of the gum. This may be due to the fact that more compounds with heteroatoms were identified in the GCMS spectrum of KS gum compared to the AF gum. The presence of such compounds may have enhanced their adsorption on the metal surface and thereby blocking the surface and protecting the metal from corrosion. The adsorption of the inhibitors was found to be exothermic and spontaneous and fitted the Langmuir adsorption model.

  4. Critical Study of Corrosion Damaged Concrete Structures

    OpenAIRE

    Sallehuddin Shah Ayop; John Cairns

    2013-01-01

    Corrosion of steel reinforcement in concrete is one of the major problems with respect to the durability of reinforced concrete structures. The degradation of the structure strength due to reinforcement corrosion decreases its design life. This paper presents the literature study on the influence of the corrosion on concrete structure starting from the mechanism of the corrosion until the deterioration stage and the structural effects of corrosion on concrete structures.

  5. Comparative study of the structure and corrosion behavior of Zr-20%Cr and Zr-20%Ti alloy films deposited by multi-arc ion plating technique

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Farhat, E-mail: ilatahraf@yahoo.com [National Centre for Nanotechnology, Department of Metallurgy and Materials Engineering (DMME), Pakistan Institute of Engineering and Applied Sciences (PIEAS), PO Nilore, Islamabad 45650 (Pakistan); Mehmood, Mazhar, E-mail: mazhar@pieas.edu.pk [National Centre for Nanotechnology, Department of Metallurgy and Materials Engineering (DMME), Pakistan Institute of Engineering and Applied Sciences (PIEAS), PO Nilore, Islamabad 45650 (Pakistan); Qasim, Abdul Mateen; Ahmad, Jamil; Naeem-ur-Rehman [National Centre for Nanotechnology, Department of Metallurgy and Materials Engineering (DMME), Pakistan Institute of Engineering and Applied Sciences (PIEAS), PO Nilore, Islamabad 45650 (Pakistan); Iqbal, Muhammad [Physics Division, Pakistan Institute of Science and Technology (PINSTECH), Islamabad 45650 (Pakistan); Qureshi, Ammad H. [Materials Division, Pakistan Institute of Science and Technology (PINSTECH), Islamabad 45650 (Pakistan)

    2014-08-01

    The primary focus of the present work was to perform comparative study of the structure as well as corrosion behavior of two Zr-rich alloy films, i.e. Zr-20%Cr and Zr-20%Ti, as well as metallic Ti, Cr and Zr films, formed by multi-arc ion plating technique. The required alloy film composition was obtained by co-deposition with proper choice of current for the targets of the constituent metals. The deposited alloy film composition was determined by energy dispersion X-ray spectroscopy, X-ray fluorescence and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) techniques, which were in close agreement with each other. The film thickness lied in the range of 550-620 nm. The crystal structure was studied by X-ray diffraction, which revealed the formation of nanocrystalline and semi-amorphous structures. The corrosion rates of the films were determined through weight loss measurement in 1 M, 6 M and 12 M hydrochloric acid (HCl) by ICP-AES analysis of the solution after immersion for 200-350 h. Anodic (potentiodynamic) polarization was also performed. Zr-20%Cr alloy film exhibited the best corrosion resistance, and its dissolution rate was less than 0.5 μm/year in 6 M HCl and about 4 μm/year in 12 M HCl. - Highlights: • Fine control over the stoichiometry of each alloy film • Development of either nano-crystalline or semi-amorphous alloy films • Development of highly corrosion resistant films.

  6. Surface mechanical properties, corrosion resistance, and cytocompatibility of nitrogen plasma-implanted nickel-titanium alloys: a comparative study with commonly used medical grade materials.

    Science.gov (United States)

    Yeung, K W K; Poon, R W Y; Chu, P K; Chung, C Y; Liu, X Y; Lu, W W; Chan, D; Chan, S C W; Luk, K D K; Cheung, K M C

    2007-08-01

    Stainless steel and titanium alloys are the most common metallic orthopedic materials. Recently, nickel-titanium (NiTi) shape memory alloys have attracted much attention due to their shape memory effect and super-elasticity. However, this alloy consists of equal amounts of nickel and titanium, and nickel is a well known sensitizer to cause allergy or other deleterious effects in living tissues. Nickel ion leaching is correspondingly worse if the surface corrosion resistance deteriorates. We have therefore modified the NiTi surface by nitrogen plasma immersion ion implantation (PIII). The surface chemistry and corrosion resistance of the implanted samples were studied and compared with those of the untreated NiTi alloys, stainless steel, and Ti-6Al-4V alloy serving as controls. Immersion tests were carried out to investigate the extent of nickel leaching under simulated human body conditions and cytocompatibility tests were conducted using enhanced green fluorescent protein mice osteoblasts. The X-ray photoelectron spectroscopy results reveal that a thin titanium nitride (TiN) layer with higher hardness is formed on the surface after nitrogen PIII. The corrosion resistance of the implanted sample is also superior to that of the untreated NiTi and stainless steel and comparable to that of titanium alloy. The release of nickel ions is significantly reduced compared with the untreated NiTi. The sample with surface TiN exhibits the highest amount of cell proliferation whereas stainless steel fares the worst. Compared with coatings, the plasma-implanted structure does not delaminate as easily and nitrogen PIII is a viable way to improve the properties of NiTi orthopedic implants.

  7. Study on corrosion simulation device for marine structural steel

    Indian Academy of Sciences (India)

    Hou Baorong; Xiang Bin

    2003-04-01

    A corrosion simulation device was studied using offshore long scale hanging specimens. An Ni–Cu–P steel specimen was studied by analysing its corrosion products and corrosion types. The appearance of the samples and the surface of the metallic substrate after the removal of the rust layer produced by these two methods were observed and compared after 470 days of exposure. The phase structure of the corrosion products under different marine environments were analysed and compared. It further indicated good correlation between the electrically connected hanging specimen method and the long scale hanging specimen method.

  8. A Comparative Study of the Inhibitory Effect of the Extracts of Ocimum sanctum, Aegle marmelos, and Solanum trilobatum on the Corrosion of Mild Steel in Hydrochloric Acid Medium

    Directory of Open Access Journals (Sweden)

    M. Shyamala

    2011-01-01

    Full Text Available A comparative study of the inhibitory effect of plant extracts, Ocimum sanctum, Aegle marmelos, and Solanum trilobatum, on the corrosion of mild steel in 1N HCl medium was investigated using weightloss method, electrochemical methods, and hydrogen permeation method. Polarization method indicates plant extracts behave as mixed-type inhibitor. The impedance method reveals that charge-transfer process mainly controls the corrosion of mild steel. On comparison, maximum inhibition efficiency was found in Ocimum sanctum with 99.6% inhibition efficiency at 6.0% v/v concentration of the extract. The plant extracts obey Langmuir adsorption isotherm. The SEM morphology of the adsorbed protective film on the mild steel surface has confirmed the high performance of inhibitive effect of the plant extracts. From hydrogen permeation method, all the plant extracts were able to reduce the permeation current. The reason for the reduced permeation currents in presence of the inhibitors may be attributed to the slow discharge step followed by fast electrolytic desorption step. Results obtained in all three methods were very much in good agreement in the order Ocimum sanctum > Aegle marmelos > Solanum trilobatum.

  9. A comparative electrochemical study of electrosorbed 2- and 4-mercaptopyridines and their application as corrosion inhibitors at C60 steel

    Indian Academy of Sciences (India)

    Nazly Hassan; Rudolf Holze

    2009-09-01

    The electrochemistry of self-assembled monolayers (SAMs) prepared from 2-mercaptopyridine (2 Mpy) and 4-mercaptopyridine (4 Mpy) dissolved in either water or an aqueous solution of 0.1 M H2SO4 on a polycrystalline gold electrode has been investigated in an aqueous electrolyte solution (0.5 M H2SO4) using cyclic voltammetry. Results suggest that 2 Mpy is adsorbed more strongly than 4 Mpy due to the formation of a S-Au-N chelate. The under- and over-potential deposition of copper from an aqueous solution of 0.1 M sulphuric acid is inhibited in the presence of these SAMs suggesting strong interactions between these adsorbates and the gold surface. A copper adlayer was partially displaced by adsorbing 2 Mpy and 4 Mpy. The inhibition effect of these SAMs on the corrosion of C60 steel has been investigated using electrochemical impedance measurements (EIM) in an aqueous 3.5 wt% NaCl solution. The polarization resistance and the inhibition efficiency were calculated. 2 Mpy has higher inhibition efficiency than 4 Mpy.

  10. Corrosion processes of triangular silver nanoparticles compared to bulk silver

    Energy Technology Data Exchange (ETDEWEB)

    Keast, V. J., E-mail: vicki.keast@newcastle.edu.au; Myles, T. A. [University of Newcastle, School of Mathematical and Physical Sciences (Australia); Shahcheraghi, N.; Cortie, M. B. [University of Technology Sydney, Institute for Nanoscale Technology (Australia)

    2016-02-15

    Excessive corrosion of silver nanoparticles is a significant impediment to their use in a variety of potential applications in the biosensing, plasmonic and antimicrobial fields. Here we examine the environmental degradation of triangular silver nanoparticles (AgNP) in laboratory air. In the early stages of corrosion, transmission electron microscopy shows that dissolution of the single-crystal, triangular, AgNP (side lengths 50–120 nm) is observed with the accompanying formation of smaller, polycrystalline Ag particles nearby. The new particles are then observed to corrode to Ag{sub 2}S and after 21 days nearly full corrosion has occurred, but some with minor Ag inclusions remaining. In contrast, a bulk Ag sheet, studied in cross section, showed an adherent corrosion layer of only around 20–50 nm in thickness after over a decade of being exposed to ambient air. The results have implications for antibacterial properties and ecotoxicology of AgNP during corrosion as the dissolution and reformation of Ag particles during corrosion will likely be accompanied by the release of Ag{sup +} ions.

  11. Vibrational Spectroscopy in Studies of Atmospheric Corrosion

    Directory of Open Access Journals (Sweden)

    Saman Hosseinpour

    2017-04-01

    Full Text Available Vibrational spectroscopy has been successfully used for decades in studies of the atmospheric corrosion processes, mainly to identify the nature of corrosion products but also to quantify their amounts. In this review article, a summary of the main achievements is presented with focus on how the techniques infrared spectroscopy, Raman spectroscopy, and vibrational sum frequency spectroscopy can be used in the field. Several different studies have been discussed where these instruments have been used to assess both the nature of corrosion products as well as the properties of corrosion inhibitors. Some of these techniques offer the valuable possibility to perform in-situ measurements in real time on ongoing corrosion processes, which allows the kinetics of formation of corrosion products to be studied, and also minimizes the risk of changing the surface properties which may occur during ex-situ experiments. Since corrosion processes often occur heterogeneously over a surface, it is of great importance to obtain a deeper knowledge about atmospheric corrosion phenomena on the nano scale, and this review also discusses novel vibrational microscopy techniques allowing spectra to be acquired with a spatial resolution of 20 nm.

  12. Vibrational Spectroscopy in Studies of Atmospheric Corrosion

    Science.gov (United States)

    Hosseinpour, Saman; Johnson, Magnus

    2017-01-01

    Vibrational spectroscopy has been successfully used for decades in studies of the atmospheric corrosion processes, mainly to identify the nature of corrosion products but also to quantify their amounts. In this review article, a summary of the main achievements is presented with focus on how the techniques infrared spectroscopy, Raman spectroscopy, and vibrational sum frequency spectroscopy can be used in the field. Several different studies have been discussed where these instruments have been used to assess both the nature of corrosion products as well as the properties of corrosion inhibitors. Some of these techniques offer the valuable possibility to perform in-situ measurements in real time on ongoing corrosion processes, which allows the kinetics of formation of corrosion products to be studied, and also minimizes the risk of changing the surface properties which may occur during ex-situ experiments. Since corrosion processes often occur heterogeneously over a surface, it is of great importance to obtain a deeper knowledge about atmospheric corrosion phenomena on the nano scale, and this review also discusses novel vibrational microscopy techniques allowing spectra to be acquired with a spatial resolution of 20 nm. PMID:28772781

  13. Numerical Study of Corrosion Crack Opening

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Frandsen, Henrik Lund; Svensson, Staffan

    2008-01-01

    for the corrosion crack opening. Experiments and theoretical analysis by a numerical method, FEM, support that the relation between the reduction of the reinforcement bar diameter due to corrosion and the corresponding increase in crack width for a given time interval, measured on the surface of a concrete specimen...... is proportional. More recently, the constant of proportionality, the so-called crack-corrosion index, has been studied further with respect to its dependence on the diameter of the reinforcement and the concrete cover. In the present paper the above-mentioned work is presented and extended with more realistic 3D......-models of the cracked concrete beam. The crack-corrosion index is evaluated for a variation of different parameters, i.e. bar diameter, concrete cover, crack length and type of corrosion product. This paper is an extended version of a paper by Thoft-Christensen et al. (2005) presented at the IFIP WG 7.5 Conference...

  14. Electrochemical Studies of Atmospheric Corrosion.

    Science.gov (United States)

    1979-01-01

    Todynamlc polarization curves using a mod ifiedatmospheric corrosion mon i tor (ACM). Norma l Tafel behavior was observed , the limiting current for oxygen...following a suggestion of Peter Serada, who is heading a task group on time-of-wetness measurements In ASTM GO1 .04, in which the author is participating...about 5 papers except for 1968 where a symposium on atmospheric corrosion was held which resulted in the publ ication of an ASTM Special Technical

  15. A comparative study on the electrochemical corrosion behavior of iron and X-65 steel in 4.0 wt % sodium chloride solution after different exposure intervals.

    Science.gov (United States)

    Sherif, El-Sayed M

    2014-07-09

    In this work, the results obtained from studying the anodic dissolution of pure iron and API X-65 5L pipeline steel after 40 min and 12 h exposure period in 4.0 wt % NaCl solutions at room temperature were reported. Potential-time, electrochemical impedance spectroscopy, potentiodynamic polarization, and chronoamperometric current-time at constant potential techniques were employed. It has been found that the iron electrode corrodes in the chloride test solutions faster than the API X-65 5L steel does under the same conditions. Increasing the exposure period for the electrodes from 40 min to 12 h showed a significant reduction in the corrosion parameters for both iron and steel in the 4.0 wt % NaCl solution. Results together confirmed clearly that the X-65 steel is superior to iron against corrosion in sodium chloride solutions.

  16. A comparative electrochemical and quantum chemical calculation study of BTAH and BTAOH as copper corrosion inhibitors in near neutral chloride solution

    Energy Technology Data Exchange (ETDEWEB)

    Finsgar, Matjaz; Lesar, Antonija; Kokalj, Anton [Jozef Stefan Institute, Department of Physical and Organic Chemistry, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Milosev, Ingrid [Jozef Stefan Institute, Department of Physical and Organic Chemistry, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Valdoltra Orthopaedic Hospital, Jadranska c. 31, SI-6280 Ankaran (Slovenia)], E-mail: ingrid.milosev@ijs.si

    2008-11-30

    The inhibition of copper corrosion in 3% NaCl solution was studied by using a well-known inhibitor, benzotriazole (BTAH), and its not so extensively explored derivative, 1-hydroxybenzotriazole (BTAOH). Electrochemical methods, i.e., linear polarization, Tafel and potentiodynamic curve measurements and electrochemical quartz crystal microbalance (EQCM) measurements were used. Corrosion parameters and inhibition effectiveness were determined. Experimental results showed that benzotriazole is a more effective inhibitor of the corrosion of copper in chloride media than 1-hydroxybenzotriazole. Whereas in the presence of BTAH a protective Cu-BTA layer is formed on the Cu surface, in the presence of BTAOH a thick, poorly protective layer is formed, which readily dissolves in chloride solution. Kinetic parameters were calculated based on EQCM results. Adsorption of BTAOH follows a linear growth law, in contrast to BTAH, whose film growth can be best represented at first by a parabolic, and later by logarithmic, growth law. Different mechanisms of growth imply different mechanisms of inhibition and account for the different inhibition effectiveness. Density functional theory calculations were performed to characterize certain features of the molecular structures, including the electronic parameters related to the inhibition effectiveness of these inhibitors. Introduction of the -OH group into the benzotriazole molecules does not change their electronic parameters significantly neither in gas phase nor in the presence of water solvent. Other parameters, therefore, affect the inhibition effectiveness of these corrosion inhibitors. In particular, superior inhibition effectiveness of BTAH is attributed to interplay of planar molecular structure, physisorption and intermolecular H-bonding, which cooperatively may result in formation of thin and protective film on the surface.

  17. Report on accelerated corrosion studies.

    Energy Technology Data Exchange (ETDEWEB)

    Mowry, Curtis Dale; Glass, Sarah Jill; Sorensen, Neil Robert

    2011-03-01

    Sandia National Laboratories (SNL) conducted accelerated atmospheric corrosion testing for the U.S. Consumer Product Safety Commission (CPSC) to help further the understanding of the development of corrosion products on conductor materials in household electrical components exposed to environmental conditions representative of homes constructed with problem drywall. The conditions of the accelerated testing were chosen to produce corrosion product growth that would be consistent with long-term exposure to environments containing humidity and parts per billion (ppb) levels of hydrogen sulfide (H{sub 2}S) that are thought to have been the source of corrosion in electrical components from affected homes. This report documents the test set-up, monitoring of electrical performance of powered electrical components during the exposure, and the materials characterization conducted on wires, screws, and contact plates from selected electrical components. No degradation in electrical performance (measured via voltage drop) was measured during the course of the 8-week exposure, which was approximately equivalent to 40 years of exposure in a light industrial environment. Analyses show that corrosion products consisting of various phases of copper sulfide, copper sulfate, and copper oxide are found on exposed surfaces of the conductor materials including wires, screws, and contact plates. The morphology and the thickness of the corrosion products showed a range of character. In some of the copper wires that were observed, corrosion product had flaked or spalled off the surface, exposing fresh metal to the reaction with the contaminant gasses; however, there was no significant change in the wire cross-sectional area.

  18. Corrosion

    Science.gov (United States)

    Slabaugh, W. H.

    1974-01-01

    Presents some materials for use in demonstration and experimentation of corrosion processes, including corrosion stimulation and inhibition. Indicates that basic concepts of electrochemistry, crystal structure, and kinetics can be extended to practical chemistry through corrosion explanation. (CC)

  19. Corrosion

    Science.gov (United States)

    Slabaugh, W. H.

    1974-01-01

    Presents some materials for use in demonstration and experimentation of corrosion processes, including corrosion stimulation and inhibition. Indicates that basic concepts of electrochemistry, crystal structure, and kinetics can be extended to practical chemistry through corrosion explanation. (CC)

  20. Electrochemical impedance spectroscopy study on corrosion inhibition of benzyltriethylammonium chloride

    Science.gov (United States)

    Idris, Mohd Nazri; Daud, Abdul Razak; Othman, Norinsan Kamil

    2013-11-01

    Electrochemical Impedance Spectroscopy (EIS) was employed to study the corrosion inhibition behavior of benzyltriethylammonium chloride (BTC) for carbon steel corrosion. The inhibition efficiency was investigated in 1.0 M HCl solution at room temperature (25°C) by varying the BTC concentration. EIS results indicated that the double layer capacitance of electrolyte/carbon steel interface decreases with the increasing of BTC concentration and consequently enhances the polarization resistance of equivalence Randles circuit. The results indicated that inhibition efficiency of as high as 65% could be achieved when 10mM BTC was present in 1.0 M HCl solution as compared to inhibitor-free solution. The inhibition process of BTC on the carbon steel corrosion was found to obey Langmuir adsorption isotherm. This study revealed that BTC is suitable to be used as a corrosion inhibitor in acid media.

  1. Microbial Influenced Corrosion (MIC) Study

    Science.gov (United States)

    2012-05-23

    low lying areas breaks down protective coating system and causes structural corrosion , • Water and organic/inorganic nutrients BUSINESS SENSITIVE...Chemical disinfection (T.O 1-1-8 and T.O 1-1-691) • Biocidal rinses and coatings • Biocidal Corrosion Preventative Compounds or CPCs BUSINESS...Type: H    Proprietary  Coating  w/ Silver  Inhibitor   Non‐Chrome Treatment + Mg‐Rich  Primer  Coupon Type: I    Prekote® (Pantheon Chemical) N/A

  2. Comparative study on CO2 corrosion behavior of N80,P110,X52 and 13Cr pipe lines in simulated stratum water

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    To better understand the carbon dioxide (CO2) corrosion behavior of carbon steel and its influence on petroleum development (including drilling,production and transportation) in the Daqing Oilfield,CO2 corrosion behaviors of N80,P110,X52 and 13Cr pipe lines in simulated solution at high temperature and high pressure condition are investigated by dynamic corrosion experiments,scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses.Results show that the corrosion rate of all pipe lines increases quickly when CO2 partial pressure increases from 0.5 to 1.5 MPa,but it slows down when CO2 partial pressure further increases from 1.5 to 4.5 MPa,during which localized corrosion is prevailing.When the experimental temperature ranges from 60 to 120°C,localized corrosion prevails.The corrosion rate of all pipe lines decreases sharply when the temperature changes from 60 to 100°C,and it becomes stable after the temperature is higher than 100°C.When the flow rate is in the range of 0–1.5 m/s,the corrosion rate of sample X52 remains unchanged,but localized corrosion gradually becomes very serious when the flow rate further increases.By analyzing the corrosion product scales of sample 13Cr,some remarkable phenomena are observed.At the temperature range of 60–100°C,the corrosion product scales are loose and thick,but become very compact when the temperature increases above 100°C.In the later case,localized corrosion is prevailing.The main components of the corrosion product scales are FeCO3 and Cr2O3.

  3. Comparative study on the corrosion behavior of the cold rolled and hot rolled low-alloy steels containing copper and antimony in flue gas desulfurization environment

    Science.gov (United States)

    Park, S. A.; Kim, J. G.; He, Y. S.; Shin, K. S.; Yoon, J. B.

    2014-12-01

    The correlation between the corrosion and microstructual characteristics of cold rolled and hot rolled low-alloy steels containing copper and antimony was established. The corrosion behavior of the specimens used in flue gas desulfurization systems was examined by electrochemical and weight loss measurements in an aggressive solution of 16.9 vol % H2SO4 + 0.35 vol % HCl at 60°C, pH 0.3. It has been shown that the corrosion rate of hot rolled steel is lower than that of cold rolled steel. The corrosion rate of cold rolled steel was increased by grain refinement, inclusion formation, and preferred grain orientation.

  4. Study on metal corrosion caused by chlorine dioxide of various purities

    Institute of Scientific and Technical Information of China (English)

    崔崇威; 黄君礼; 许晶

    2004-01-01

    Weight lost method was used to comparatively study the corrosion behavior of four different metals under the dosage of chlorine dioxide, chlorine and their mixture respectively. The experimental results indicated that chlorine causes the most serious corrosion of carbon steel, and the higher the concentration of chlorine, the more serious the corrosion. On the contras, metals corrosion is the least serious in the case of chlorine dioxide.The results further revealed that chlorine dioxide is the most effective water treatment reagent, making it the best choice to use extensively in circulated cooling water disinfection and corrosion control.

  5. Hanford double shell waste tank corrosion studies - final report FY2014

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fuentes, R. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hicks, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2014-12-19

    SRNL tasks for FY14 included studies to evaluate the susceptibility of carbon steel to vapor space corrosion (VSC), liquid-air interface (LAI) corrosion, and pitting corrosion. Additionally, SRNL evaluated the susceptibility of carbon steel to pitting corrosion under buffered waste conditions, with the objective of determining the adequate amount of inhibitor (e.g., nitrite) necessary to mitigate pitting corrosion. Other CPP experiments were performed in historical waste simulants and the results were compared to previously gathered results. The results of these activities were utilized to assess the robustness of the standardized CPP protocol

  6. MICROSCOPIC CORROSION STUDIES OF DUPLEX STAINLESS STEELS

    Institute of Scientific and Technical Information of China (English)

    C.Leygraf; J.Pan; M.Femenia

    2004-01-01

    Electrochemical scanning tunneling microscopy and scanning electrochemical microscopy have been used for in situ monitoring of localized corrosion processes of different Duplex stainless steels (DSS) in acidic chloride solutions. The techniques allow imaging of local dissolution events with micrometer resolution, as opposed to conventional electrochemical techniques, which only give an overall view of the corrosion behavior. In addition, combined scanning Kelvin probe force microscopy and magnetic force microscopy were used for mapping the Volta potential variation over the surface of DSSs. A significant difference in Volta potential between the austenite and ferrite phases suggests galvanic interaction between the phases. A compositional gradient appears within 2 micrometers across the phase boundary, as seen with scanning Auger microscopy (SAM). In all, the studies suggest that higher alloyed DSS exhibit a more homogeneous dissolution behavior than lower alloyed DSS, due to higher and more similar corrosion resistance of the two phases, and enhanced resistance of the ferrite/austenite phase boundary regions.

  7. Comparative study of the microbiological corrosion among an AISI 304L and an API X65; Estudio comparativo de la corrosion microbiologica entre un AISI 304L y un API X65

    Energy Technology Data Exchange (ETDEWEB)

    Diaz S, A.; Arganis J, C.; Luna C, P.; Carapia M, L. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Gonzalez F, E. [ITT, Toluca, Estado de Mexico (Mexico)

    2004-07-01

    Metallic samples of AISI 304L sensitized and API X65, were subjected to the action of an inoculated media with reductive sulphate microorganisms (SBR), carrying out electrochemical evaluations by means of the techniques of Polarization Resistance (RP), Tafel extrapolation (ET) and Electrochemical Noise (RE). The generated information was complemented with the analysis and diagnostic of the present damage in the surfaces exposed in both metals. The used electrochemical techniques allow to determine the corrosion velocities associated to each system, establishing that the uniform corrosion is not affected by the effect of the microorganisms; however, electrochemical noise, evidenced the formation of stings associated to the presence of bacteria. (Author)

  8. Corrosion studies in brines of the Salton Sea Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Carter, J.P.; McCawley, F.X.; Cramer, S.D.; Needham, P.B. Jr.

    1979-01-01

    Toward the goal of maximizing minerals and metals recovery from domestic resources, the Bureau of Mines, U.S. Department of the Interior, has conducted in situ corrosion studies at the Salton Sea Known Geothermal Resources Area (KGRA) in the Imperial Valley, Calif., to evaluate and characterize materials of construction for geothermal resources recovery plants. General-, pitting, and crevice-corrosion characteristics of 13 commercially available alloys were investigated for periods of 15 and 30 days in seven process environments expected to be found in typical geothermal resources plants. Stainless steel alloy 29-4, Inconel 625, and the Hastelloys G, S, and C-276 were the most resistant to general corrosion, did not pit, and exhibited little susceptibility to crevice corrosion. Stainless steel alloys 430, E-Brite 26-1, and 6X had low general corrosion rates, but pitted and were susceptible to crevice corrosion. Stainless steel alloy 316 L had a low corrosion rate, but corroded intergranularly, pitted, and was susceptible to crevice corrosion and to stress-corrosion cracking. Titanium--1.5 nickel and TiCode-12 had low corrosion rates, did not pit, and were not susceptible to crevice corrosion. Carbon and 4130 steels had high corrosion rates, pitted, and had high susceptibilities to crevice corrosion. The major scale-forming mineral on the corrosion samples in most of the process environments studied was galena mixed with lesser amounts of other minerals.

  9. Urban and marine corrosion: Comparative behaviour between field and laboratory conditions

    Energy Technology Data Exchange (ETDEWEB)

    Iribarren Laco, J.I.; Liesa Mestres, F.; Bilurbina Alter, L. [Departament d' Enginyeria Quimica E.T.S.E.I.B. Universitat Politecnica de Catalunya, Barcelona (Spain); Cadena Villota, F. [Departamento de Materiales, Escuela Politecnica Nacional, Quito (Ecuador)

    2004-09-01

    A detailed study of the corrosion phenomena of carbon steel has been investigated in this work by means of the comparison of field and laboratory tests. Two areas of the metropolitan area of Barcelona (Spain) were selected to carry out the field tests, whereas two different solutions of sodium chloride and sodium hydrogen sulfite were used to simulate the field conditions by means of cyclic laboratory tests. The corrosion rate has been evaluated from the weight loss of the specimens and the morphology surface has been visualized by optical and scanning electron microscopy. Corrosion products and contaminants have been analyzed by X-ray diffraction and energy-dispersive X-ray spectroscopy, respectively. The penetration results can be adjusted to the Passano equation and the corrosivity degree can be assigned in accordance with ISO standards. A correlation between field and laboratory tests has been found, by comparing the specimens with the same degree of corrosion, showing the validity of the accelerated laboratory tests in order to simulate the field conditions. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  10. Corrosion behavior of tantalum-coated cobalt-chromium modular necks compared to titanium modular necks in a simulator test.

    Science.gov (United States)

    Dorn, Ulrich; Neumann, Daniel; Frank, Mario

    2014-04-01

    This study compared the corrosion behavior of tantalum-coated cobalt-chromium modular necks with that of titanium alloy modular necks at their junction to titanium-alloy femoral stem. Tests were performed in a dry assembly and two wet assemblies, one contaminated with calf serum and the other contaminated with calf serum and bone particles. Whereas the titanium modular neck tested in the dry assembly showed no signs of corrosion, the titanium modular necks tested in both wet assemblies showed marked depositions and corrosive attacks. By contrast, the tantalum-coated cobalt-chromium modular necks showed no traces of corrosion or chemical attack in any of the three assemblies. This study confirms the protective effect of tantalum coating the taper region of cobalt-chromium modular neck components, suggesting that the use of tantalum may reduce the risk of implant failure due to corrosion.

  11. A Study on Corrosion Resistance of Coating System on Steel

    Energy Technology Data Exchange (ETDEWEB)

    Nah, Hwan Seon; Lee, Hyeon Ju; Kim, Kang Seok [Korea Electricity Power Research Institute, Daejeon (Korea, Republic of); Lee, Chul Woo [KEPCO E and Co., Yongin (Korea, Republic of)

    2007-04-15

    The design purpose of architectural finish on steel structures is to prevent corrosion in the respect of structural durability, function, beauty and economy. In particular, as structures located on shores is easily degraded due to damage from salt, it is necessary to evaluate the applied coating systems on steel structures. This study is focused on anti-corrosive tests of both steel surfaces and high strength bolts. Two kinds of tests were conducted on each specimen under the condition of outdoor exposure and salt spray comparatively during 760 hours. In case of coating systems on steel surfaces, three layered coating system showed the best function among the various coating systems. Regarding the coating systems on high strength bolts, the coating system composed of zinc dust on hot dip galvanized coating was found to be the best against corrosion.

  12. Study of biofilm influenced corrosion on cast iron pipes in reclaimed water

    Science.gov (United States)

    Zhang, Haiya; Tian, Yimei; Wan, Jianmei; Zhao, Peng

    2015-12-01

    Biofilm influenced corrosion on cast iron pipes in reclaimed water was systemically studied using the weight loss method and electrochemical impedance spectroscopy (EIS). The results demonstrated that compared to sterile water, the existence of the biofilm in reclaimed water promoted the corrosion process significantly. The characteristics of biofilm on cast iron coupons were examined by the surface profiler, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The bacterial counts in the biofilm were determined using the standard plate count method and the most probable number (MPN). The results demonstrated that the corrosion process was influenced by the settled bacteria, EPS, and corrosion products in the biofilm comprehensively. But, the corrosion mechanisms were different with respect to time and could be divided into three stages in our study. Furthermore, several corresponding corrosion mechanisms were proposed for different immersion times.

  13. Comparative corrosive characteristics of petroleum diesel and palm biodiesel for automotive materials

    Energy Technology Data Exchange (ETDEWEB)

    Fazal, M.A.; Haseeb, A.S.M.A.; Masjuki, H.H. [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2010-10-15

    Corrosive characteristics of biodiesel are important for long term durability of engine parts. The present study aims to compare the corrosion behavior of aluminum, copper and stainless steel in both petroleum diesel and palm biodiesel. Immersion tests in biodiesel (B100) and diesel (B0) were carried out at 80 C for 1200 h. At the end of the test, corrosion characteristic was investigated by weight loss measurements and changes on the exposed metal surface. Surface morphology was examined by optical microscope and scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDS). Fuels were analyzed by using TAN analyzer, FTIR, GCMS and ICP in order to investigate the acid concentration, oxidation level with water content, compositional characteristics and presence of metal species respectively. Results show that the extent of corrosion and change in fuel properties upon exposure to metals are more in biodiesel than that in diesel. Copper and aluminum were susceptible to attack by biodiesel whereas stainless steel was not. (author)

  14. The Study on Inner Corrosion Sensor for ACSR

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong Boo; Jeong, Jae Kee; Sim, Eung Bo; Woo, Jeong Wook [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

    1996-12-31

    Life time estimations of the ACSR by mechanically analyzing the aluminum and steel strands of the ACSR. Finding corrosion trends of the industrial and marine area. Analyzing mechanical corrosion characteristics in case of artificial corrosion tests(the salt water spraying chamber, the sulphureous acid gas chamber). Defining the sorts of corrosion factors. Mechanical tests of used samples which be collected from the fields. Designing the ECT sensor and studying theoretical basis. Life time estimations of the ACSR over-head lines by means of ECT test. Designing and Implementing the corrosion detector using ECT for the real test in the future. (author). 15 refs., figs.

  15. Prompt gamma analysis of chlorine in concrete for corrosion study

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)]. E-mail: aanaqvi@kfupm.edu.sa; Nagadi, M.M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2006-02-15

    Measurement of chlorine in concrete is very important for studying of corrosion of reinforcing steel in concrete. Corrosion of reinforcing steel is primarily ascribed to the penetration of chloride ions to the steel surface. Preventive measures for avoiding concrete structure reinforcement corrosion requires monitoring the chloride ion concentration in concrete so that its concentration does not exceed a threshold limit to initiate reinforcement concrete corrosion. An accelerator based prompt gamma neutron activation analysis (PGNAA) setup has been developed for non-destructive analysis of elemental composition of concrete samples. The setup has been used to measure chlorine concentration in concrete samples over a 1-3 wt% concentration range. Although a strong interference has been observed between the chlorine {gamma}-rays and calcium {gamma}-rays from concrete, the chlorine concentration in concrete samples has been successfully measured using the 1.164 and 7.643 MeV chlorine {gamma}-rays. The experimental data were compared with the results of the Monte Carlo simulations. An excellent agreement has been achieved between the experimental data and results of Monte Carlo simulations. The study has demonstrated the successful use of the accelerator-based PGNAA setup in non-destructive analysis of chlorine in concrete samples.

  16. Prompt gamma analysis of chlorine in concrete for corrosion study.

    Science.gov (United States)

    Naqvi, A A; Nagadi, M M; Al-Amoudi, O S B

    2006-02-01

    Measurement of chlorine in concrete is very important for studying of corrosion of reinforcing steel in concrete. Corrosion of reinforcing steel is primarily ascribed to the penetration of chloride ions to the steel surface. Preventive measures for avoiding concrete structure reinforcement corrosion requires monitoring the chloride ion concentration in concrete so that its concentration does not exceed a threshold limit to initiate reinforcement concrete corrosion. An accelerator based prompt gamma neutron activation analysis (PGNAA) setup has been developed for non-destructive analysis of elemental composition of concrete samples. The setup has been used to measure chlorine concentration in concrete samples over a 1-3 wt% concentration range. Although a strong interference has been observed between the chlorine gamma-rays and calcium gamma-rays from concrete, the chlorine concentration in concrete samples has been successfully measured using the 1.164 and 7.643 MeV chlorine gamma-rays. The experimental data were compared with the results of the Monte Carlo simulations. An excellent agreement has been achieved between the experimental data and results of Monte Carlo simulations. The study has demonstrated the successful use of the accelerator-based PGNAA setup in non-destructive analysis of chlorine in concrete samples.

  17. Flow accelerated corrosion study in feeder pipes

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, P.; Verma, V.; Singh, R.K. [Bhabha Atomic Research Centre, Mumbai (India). Reactor Safety Div.

    2014-11-15

    The Indian Pressurized Heavy Water Reactor (PHWR) core consists of a number of horizontal channels containing nuclear fuel bundles. Parallel coolant channels are connected to Inlet and Outlet header through feeder pipes. Coolant from Reactor Inlet Header is distributed to the coolant channels and after removing heat combines at Reactor Outlet Header. Due to space constraints the feeder pipes are joined to the channel with one or two elbows close to the end fittings of the coolant channels. The carbon steel feeder pipes carry high temperature fluid at higher velocity and are liable to undergo Flow Accelerated Corrosion (FAC). In the recent inspection it has been found that feeders having double elbow are more susceptible to FAC on the intrados of second elbow. But it was found that in some of the elbows maximum thinning due to FAC was observed on the intrados of the first elbow. Hence to resolve this, effect of first bend orientation with respect of upstream direction has been studied. Two different approaches are used for predicting the FAC rate from calculated value of wall shear stress by CFD. One method is based on evaluating of wear rate using Colburn analogy and the other using an empirical equation between wear rate and shear stress. In Colburn analogy, mass transfer coefficient is evaluated by knowing shear stress and equilibrium concentration. For a case study, wall shear stress obtained from k-ε turbulence model was compared with k-ω SST turbulence model and no appreciable change in the wall shear stress has been found. Hence for subsequent analysis k-ε turbulence model was chosen because large mesh size near to the surface (first layer thickness) is permitted due to higher y{sup +} value.

  18. Comparing thermal stimulation techniques in infrared thermographic inspection of corrosion in steel

    Science.gov (United States)

    Chulkov, A. O.; Vavilov, V. P.

    2015-04-01

    Remote detection of corrosion in metals is a developing application area of active thermal nondestructive testing. In this study, emphasis is made on the optimization of heating techniques that is of a major interest in practical surveys. Some popular data processing techniques, such as Fourier transform, correlation and principal component analysis, are also quantitatively compared in application to corrosion detection in 1-2 mm thick steel by applying a criterion of signal-to-noise ratio. The best inspection results have been obtained by using powerful halogen lamps and air blowers. Material loss of about 25% with lateral dimensions greater than 10×10 mm can be reliably identified in practical tests. The use of Xenon flash tubes is inefficient because of significant steel thickness. LED panels have not provided expected results due to low absorption of LED quasi-monochromatic radiation.

  19. Corrosion in waste-fired boilers: A thermodynamic study

    DEFF Research Database (Denmark)

    Becidan, Michael; Sørum, Lars; Frandsen, Flemming

    2009-01-01

    A twofold study using thermodynamic equilibrium calculations was carried out to study corrosion in MSW incinerators. Corrosion was associated with the amount of alkalis and trace metals gaseous chlorides. Firstly, a two-level factorial experimental design combined with a data analysis were used...... corrosion-fighting additives (ammonium sulphate and silica) was investigated. Calculations confirmed experimental results and brought further insight on differentiated results for Na, K, Pb and Zn but also on capture mechanisms....

  20. Comparative Behaviour of Nitrite and Nitrate for the Protection of Rebar Corrosion

    Science.gov (United States)

    Ahmad, Altaf; Kumar, Anil

    2016-10-01

    Corrosion of rebar steel due to environmental causes has been studied through various approaches, and among the protection techniques use of inhibitors has gained encouragement. Nitrites and nitrates of sodium have gained sufficient scientific coverage. Recently, nitrites and nitrates of calcium have been verified in some studies, which, however, needs further experimentation through different angles. Simple polarization technique has been utilized in the present study to compare inhibitive efficiency of these salts of sodium and calcium, which indicate that calcium salts are more efficient.

  1. Studies on corrosion control of naphtha fractions in overhead condensing system using laboratory distillation device

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, R.C.; Jayaraman, A.; Chauhan, R.K; Goyal, H.B. [Indian Institute of Petroleum, Dehradun-248005 (India)

    2010-10-15

    Corrosion in the overhead condensing system of atmospheric distillation units is a common occurrence in petroleum refineries worldwide. These corrosion problems are influenced by the presence of three phases: vapours, liquid hydrocarbons and aqueous phase containing hydrochloric acid formed during distillation by decomposition of chloride salts of calcium and magnesium. Present studies highlight the corrosion control of naphtha fractions of Bombay High and Dubai crude oils in laboratory distillation device by chemical treatment using various corrosion inhibitors having different functional groups. These studies were carried out using two phase systems (aqueous-hydrocarbon) in the distillation device having facilities for monitoring the corrosion and temperatures in vapour condensing region and liquid condensate. Corrosion monitoring was carried out by potentiodynamic polarization technique and dissolved iron analysis using inductively coupled plasma atomic emission spectroscopy (ICPAES). Experimental findings indicate that Dubai naphtha fraction is more corrosive in nature when compared to Bombay High naphtha. This observation can also be explained on the basis of characterization of both crude oils and their naphtha fractions. At normally recommended dosage level as in refinery overhead systems, water soluble corrosion inhibitors are more effective than hydrocarbon soluble ones in the vapour condensing region as well as in the liquid condensate of both naphtha fractions. (author)

  2. Aircraft Integral Fuel Tank Corrosion Study

    Science.gov (United States)

    2007-11-02

    biology of Amorphoteca resinae . Materials und Organismen, 6, (3), p. 161, (1971). 8. D. Cabral. Corrosion by microorganisms of jet aircraft integral fuel...the mycelium of the fungus Hormoconis resinae in the MIC of Al alloys. Proc. XI Int. Corrosion Congress, Houston, USA, 5B, p. 3773, (1993). 14. M

  3. Electrochemical and Corrosion Inhibition Studies of Cucurbita Maxima

    Directory of Open Access Journals (Sweden)

    K. Anbarasi

    2016-08-01

    Full Text Available The influence of the acid extract of peel of Cucurbita maxima (PCM on the corrosion of mild steel in 1N H2SO4 was investigated by weight loss, polarization and impedance methods and SEM analysis. The inhibition efficiency increases with extract concentration and immersion period. Weight loss and corrosion rates of mild steel decreased as the concentration of inhibitor increased. The results showed that PCM was potential corrosion inhibitor and maximum inhibition efficiency (IE % obtained was 98% for 3%PCM at 1h. Impedance measurement results an increase in charge transfer resistance (Rct, which also confirms the corrosion inhibitive nature of the plant extract. Potentiodynamic study showed that PCM acts as a mixed type of inhibitor, which controls both the anodic and cathodic reactions. Scanning electron microscopic studies provided the evidence of improved surface condition for the corrosion protection, due to the adsorption.

  4. Chemical treatment of zinc surface and its corrosion inhibition studies

    Indian Academy of Sciences (India)

    S K Rajappa; T V Venkatesha; B M Praveen

    2008-02-01

    The surface treatment of zinc and its corrosion inhibition was studied using a product (BTSC) formed in the reaction between benzaldehyde and thiosemicarbozide. The corrosion behaviour of chemically treated zinc surface was investigated in aqueous chloride–sulphate medium using galvanostatic polarization technique. Zinc samples treated in BTSC solution exhibited good corrosion resistance. The measured electrochemical data indicated a basic modification of the cathode reaction during corrosion of treated zinc. The corrosion protection may be explained on the basis of adsorption and formation of BTSC film on zinc surface. The film was binding strongly to the metal surface through nitrogen and sulphur atoms of the product. The formation of film on the zinc surface was established by surface analysis techniques such as scanning electron microscopy (SEM–EDS) and Fourier transform infrared spectroscopy (FTIR).

  5. Study of surface interactions of ionic liquids with aluminium alloys in corrosion and erosion corrosion processes

    Science.gov (United States)

    Bermúdez, María-Dolores; Jiménez, Ana-Eva; Martínez-Nicolás, Ginés

    2007-06-01

    Surface interactions of alkylimidazolium ionic liquids (ILs) with aluminium alloy Al 2011 have been studied by immersion tests in seven neat ILs [1- n-alkyl-3-methylimidazolium X - (X = BF 4; n = 2 (IL1), 6 (IL2), 8 (IL3). X = CF 3SO 3; n = 2 (IL4). X = (4-CH 3C 6H 4SO 3); n = 2 (IL5). X = PF 6; n = 6 (IL6)] and 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide (IL7)]. Immersion tests for Al 2011 have also been carried out in 1 wt.% and 5 wt.% solutions of 1-ethyl,3-methylimidazolium tetrafluoroborate (IL1) in water. No corrosion of Al 2011 by neat ILs is observed. The highest corrosion rate for Al 2011 in water is observed in the presence of a 5 wt.% IL1 due to hydrolysis of the anion with hydrogen evolution and formation of aluminium fluoride. Erosion-corrosion processes have been studied for three aluminium alloys (Al 2011, Al 6061 and Al 7075) in a 90 wt.% IL1 solution in water in the presence of α-alumina particles. The erosion-corrosion rates are around 0.2 mm/year or lower, and increase with increasing copper content to give a corrosion resistance order of Al 6061 > Al 7075 > Al 2011. Results are discussed on the basis of scanning electron microscopy (SEM) observations, energy dispersive spectroscopy (EDS) analysis, X-ray diffraction (XRD) patterns and X-ray photoelectron spectroscopy (XPS) determinations.

  6. Review of the studies on fundamental issues in LBE corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jinsuo [International Nuclear System Engineering Group, Decision Application Division, MS K-575, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Material Physics and Applications Division, Los Alamos National Laboratory (United States)], E-mail: jszhang@lanl.gov; Li Ning [International Nuclear System Engineering Group, Decision Application Division, MS K-575, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Material Physics and Applications Division, Los Alamos National Laboratory (United States)

    2008-02-15

    Lead bismuth eutectic (LBE) technology is being developed for applications in advanced nuclear systems and high-power spallation neutron targets. In this paper, the current understanding of corrosion and the fundamental issues relevant to corrosion when using LBE as a heavy liquid metal nuclear coolant are reviewed. Corrosion mechanisms and processes in LBE are examined. Prospective methods to mitigate corrosion are briefly surveyed. We then discuss the oxygen control technique for corrosion mitigation in detail, including the range of oxygen concentrations in LBE, oxygen sensors, and the surface oxidation kinetics. Existing experimental results are summarized and reviewed. Theoretical corrosion models for non-isothermal liquid metal loops are refined and compared each other. The applications of these models to a few practical lead-alloy systems are used to illustrate the corrosion mechanisms and the parameter dependency, and to benchmark. Based on the current state of knowledge, a number of R and D tasks are proposed to fill the gaps and firmly establish the scientific underpinning before LBE nuclear coolant technology is ready for programmatic and industrial applications.

  7. Corrosion of archaeological iron artefacts compared to modern iron at the waterlogged site Nydam, Denmark

    DEFF Research Database (Denmark)

    Matthiesen, Henning; Hilbert, Lisbeth Rischel; Gregory, David;

    2004-01-01

    loss, corrosion potential, electrochemical impedance spectroscopy and electrical resistivity. 3) Measurements of environmental parameter such as water level, redox potential, oxygen concentration, soil pH, and the concentration of a range of dissolved species in the pore water. This presentation shows...... focuses solely on the iron objects. A three-pronged approach has been used in the studies in Nydam: Studies of the excavated artefacts, including the compositon of corrosion products and a mapping of their exact state of preservation. 2) Use of modern iron samples placed in the soil for studies of weight...... some of the results obtained during the seven years of studies at the site. It is demonstrated how the three pronged approach is useful in understanding not only the current corrosion rate and threats against the artefacts but also the corrosion history, i.e. when were the deterioration patterns...

  8. Electrochemical Study of Welded AISI 304 and 904L Stainless Steel in Seawater in View of Corrosion

    Directory of Open Access Journals (Sweden)

    Richárd Székely

    2010-10-01

    Full Text Available This is a comparative study of the corrosion behaviour of welds in AISI 304 and AISI 904L stainless steels carried out in seawater model solution in the temperature range 5-35°C and the standard of corrosion testing of welds was followed. The corrosion rate and corrosion attack characteristics were determined for welds of the examined steels with several type of treatment. The aim of this work was to compare the steels based on their resistance against the corrosion in terms of pitting potential (Epit and repassivation potential (Erepass. Seawater is an electrochemically aggressive medium, which can initiate localised corrosion in welded stainless steels. Different electrochemical and testing methods were used, including cyclic voltammetry, chronopotentiometry, electrochemical impedance spectroscopy (EIS, pH measuring and penetration tests.

  9. The corrosion of aluminum in dilute solutions: laboratory studies

    Energy Technology Data Exchange (ETDEWEB)

    Draley, J.E.; Arendt, J.W.; English, G.C.; Story, E.F.; Wainscott, M.M.; Berger, R.W.

    1945-06-19

    After it had been decided that aluminum was to be used as a corrosion-resistant material with good heat transfer properties, it was desired to determine the operating conditions to be used in the water-cooled Handford plant in order to avoid danger of corrosion penetration of thin aluminum parts. The studies here reported were undertaken with the object of determining these conditions by investigating the effects of all the known variables which might influence the corrosion behavior of aluminum in a water-coolded plant at HEW. The addition of hydrogen peroxide to the testing solutions was the only effort made to simulate special conditions at the plant.

  10. The corrosion of aluminum in dilute solutions: laboratory studies

    Energy Technology Data Exchange (ETDEWEB)

    Draley, J.E.; Arendt, J.W.; English, G.C.; Story, E.F.; Wainscott, M.M.; Berger, R.W.

    1945-06-19

    After it had been decided that aluminum was to be used as a corrosion-resistant material with good heat transfer properties, it was desired to determine the operating conditions to be used in the water-cooled Handford plant in order to avoid danger of corrosion penetration of thin aluminum parts. The studies here reported were undertaken with the object of determining these conditions by investigating the effects of all the known variables which might influence the corrosion behavior of aluminum in a water-coolded plant at HEW. The addition of hydrogen peroxide to the testing solutions was the only effort made to simulate special conditions at the plant.

  11. Study on corrosive grinding of gears

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Careful grinding or honing is usually required in machining of gears in order to improvethe machining quality of gear surface. Thus several grinding additives were used to formulate syn-thetic grinding lubricants similar to superior running-in lubricants. Experimental results show thatthe tooth surface of the produced oblique gear and steel worm becomes extremely smooth aftergrinding at a certain load for about a half to one hour. Especially, the gear surface finished withspecially formulated grinding lubricant reaches mirror-like smoothness. The quality of the geartooth can be improved by corrosive grinding, while the corrosive grinding time can be controlled byadjusting the quantity of the corrosive additives and the speed and load of the gears.

  12. Army Aviation Corrosion Engineering Case Studies

    Science.gov (United States)

    2010-02-10

    Support Rod 7 Yourfilename.ppt H-47 FRIES Bar Support Rod Corrosion • Resolution • ASAM H-47-09- ASAM -04 is issued • Requires inspection and grading...Analysis • Failure Analysis • Risk Analysis 12 Yourfilename.ppt H-60 SAS Link SCC Failure • The Resolution • Issue a message H060-10- ASAM -04 • Inspect all

  13. Corrosion studies: geopressured aquifer gas production

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, A.N. (Bechtel Group, Inc., San Francisco, CA); Weekes, M.C.; Schoepflin, F.; Sharer, J.C.; Bebout, D.G.; Bachman, A.L. (eds.)

    1981-01-01

    Analytical data, obtained on brine from three geopressured wells in Louisiana and one in Texas are presented. The chloride ion concentration of each brine is plotted against the total dissolved solids. Sulfate and bicarbonate ion concentrations are plotted against total dissolved solids. Experience with geothermal power plants, alternatives for corrosion prevention, and monitoring and test techniques are discussed. (MHR)

  14. The Study Programm Report of the Corrosion Behavior of New Zirconium-based Alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The corrosion of fuel cladding in PWR limits the extension of burnup. To compare the corrosion resistance of Zr-4 and new zirconium-based alloys, the out-of-pile water-side corrosion test has been conducted for these materials.To study the effects of heat flux on the corrosion of cladding, and keep the surface of cladding as an original ’as-received’ statement, the heat elements are introduced into the inside of the cladding tubes.The materials have been exposed for 205 d till now. The oxide film performed on the surface of cladding is black and glossy. The thickness of oxide is measured by the method of eddy current.

  15. Comparative study of N-[(4-methoxyphenyl (morpholin-4-ylmethyl]acetamide (MMPA and N-[morpholin-4-yl(phenylmethyl]acetamide (MPA as corrosion inhibitors for mild steel in sulfuric acid solution

    Directory of Open Access Journals (Sweden)

    A. Jamal Abdul Nasser

    2017-02-01

    Full Text Available Two Mannich bases namely, N-[(4-methoxyphenyl(morpholin-4-ylmethyl]acetamide (MMPA and N-[morpholin-4-yl(phenylmethyl]acetamide (MPA were synthesized and their influence on the inhibition of corrosion of mild steel in 1.0 M H2SO4 was investigated by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS, scanning electron microscopy (SEM and FT-IR spectroscopy. The weight loss measurements showed that these inhibitors have excellent inhibiting effect at a concentration of 0.01 M. The inhibitor efficiency was found to depend on both concentration and molecular structure of the inhibitor. Both the compounds have been found to be relatively good inhibitors. Potentiodynamic polarization curves revealed that the studied inhibitors represent a mixed-type, predominantly cathodic control. An equivalent circuit is suggested based on an analysis of EIS data. The negative value of standard free energy of adsorption in the presence of inhibitor suggests spontaneous adsorption of inhibitors on the mild steel surface. The activation energy of corrosion and other thermodynamic parameters were calculated to elaborate the mechanism of corrosion inhibition. The Temkin isotherm was found to provide an accurate description of the adsorption behavior of the inhibitors. Surface analysis using scanning electron microscope (SEM shows a significant morphological improvement on the mild steel surface with the addition of inhibitors. FT-IR spectra revealed the interaction between inhibitor molecules and mild steel surface.

  16. TREATMENT TANK CORROSION STUDIES FOR THE ENHANCED CHEMICAL CLEANING PROCESS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B.

    2011-08-24

    Radioactive waste is stored in high level waste tanks on the Savannah River Site (SRS). Savannah River Remediation (SRR) is aggressively seeking to close the non-compliant Type I and II waste tanks. The removal of sludge (i.e., metal oxide) heels from the tank is the final stage in the waste removal process. The Enhanced Chemical Cleaning (ECC) process is being developed and investigated by SRR to aid in Savannah River Site (SRS) High-Level Waste (HLW) as an option for sludge heel removal. Corrosion rate data for carbon steel exposed to the ECC treatment tank environment was obtained to evaluate the degree of corrosion that occurs. These tests were also designed to determine the effect of various environmental variables such as temperature, agitation and sludge slurry type on the corrosion behavior of carbon steel. Coupon tests were performed to estimate the corrosion rate during the ECC process, as well as determine any susceptibility to localized corrosion. Electrochemical studies were performed to develop a better understanding of the corrosion mechanism. The tests were performed in 1 wt.% and 2.5 wt.% oxalic acid with HM and PUREX sludge simulants. The following results and conclusions were made based on this testing: (1) In 1 wt.% oxalic acid with a sludge simulant, carbon steel corroded at a rate of less than 25 mpy within the temperature and agitation levels of the test. No susceptibility to localized corrosion was observed. (2) In 2.5 wt.% oxalic acid with a sludge simulant, the carbon steel corrosion rates ranged between 15 and 88 mpy. The most severe corrosion was observed at 75 C in the HM/2.5 wt.% oxalic acid simulant. Pitting and general corrosion increased with the agitation level at this condition. No pitting and lower general corrosion rates were observed with the PUREX/2.5 wt.% oxalic acid simulant. The electrochemical and coupon tests both indicated that carbon steel is more susceptible to localized corrosion in the HM/oxalic acid environment than

  17. Pitting corrosion of copper. An equilibrium - mass transport study

    Energy Technology Data Exchange (ETDEWEB)

    Taxen, C. [Swedish Corrosion Inst., Stockholm (Sweden)

    2002-08-01

    A mathematical model for the propagation of corrosion pits is described and used to calculate the potentials below which copper is immune to pitting. The model uses equilibrium data and diffusion coefficients and calculates the stationary concentration profiles of 26 aqueous species from the bulk water outside a corrosion pit to the site of the metal dissolution. Precipitation of oxides and salts of copper is considered. Studied conditions include water compositions from tap waters to seawater at the temperatures 25 deg C and 75 deg C. Carbonate and sulphate are aggressive towards copper because of complex formation with divalent copper. Carbonate is less aggressive in a corrosion pit than outside at the pH of the bulk. Carbonate carries acidity out from the pit, favours oxide formation and may prevent the initiation of acidic corrosion pits. The concentration profiles are used to estimate the maximum propagation rates for a corrosion pit. A high potential is found to be the most important factor for the rate of propagation. The levels of potential copper can sustain, as corrosion potentials are discussed in terms of the stability of cuprous oxide as a cathode material for oxygen reduction relative to non-conducting cupric phases.

  18. Study of Corrosion in a Biomass Boiler

    Directory of Open Access Journals (Sweden)

    C. Berlanga

    2013-01-01

    Full Text Available Biomass plants, apart from producing energy, help to reduce CO2(g emissions. One of the biggest problems for their development is superheater corrosion due to fuel corrosivity, especially of the straw. This limits both the temperature of the vapour and also the effectiveness of the plant. In order to know more about the reactions which happen inside the boiler of biomass, thermodynamic calculations using software (HSC Chemistry have been carried out. Field tests have been carried out in the Sangüesa Biomass Plant in Navarra (Spain: determination of the types of oxides and the deposits formed on the superheaters tubes as well as a program to measure temperatures. Finally, the global results are discussed.

  19. Atomic level characterization in corrosion studies

    Science.gov (United States)

    Marcus, Philippe; Maurice, Vincent

    2017-06-01

    Atomic level characterization brings fundamental insight into the mechanisms of self-protection against corrosion of metals and alloys by oxide passive films and into how localized corrosion is initiated on passivated metal surfaces. This is illustrated in this overview with selected data obtained at the subnanometre, i.e. atomic or molecular, scale and also at the nanometre scale on single-crystal copper, nickel, chromium and stainless steel surfaces passivated in well-controlled conditions and analysed in situ and/or ex situ by scanning tunnelling microscopy/spectroscopy and atomic force microscopy. A selected example of corrosion modelling by ab initio density functional theory is also presented. The discussed aspects include the surface reconstruction induced by hydroxide adsorption and formation of two-dimensional (hydr)oxide precursors, the atomic structure, orientation and surface hydroxylation of three-dimensional ultrathin oxide passive films, the effect of grain boundaries in polycrystalline passive films acting as preferential sites of passivity breakdown, the differences in local electronic properties measured at grain boundaries of passive films and the role of step edges at the exposed surface of oxide grains on the dissolution of the passive film. This article is part of the themed issue 'The challenges of hydrogen and metals'.

  20. TREATMENT TANK CORROSION STUDIES FOR THE ENHANCED CHEMICAL CLEANING PROCESS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B.

    2011-08-24

    Radioactive waste is stored in high level waste tanks on the Savannah River Site (SRS). Savannah River Remediation (SRR) is aggressively seeking to close the non-compliant Type I and II waste tanks. The removal of sludge (i.e., metal oxide) heels from the tank is the final stage in the waste removal process. The Enhanced Chemical Cleaning (ECC) process is being developed and investigated by SRR to aid in Savannah River Site (SRS) High-Level Waste (HLW) as an option for sludge heel removal. Corrosion rate data for carbon steel exposed to the ECC treatment tank environment was obtained to evaluate the degree of corrosion that occurs. These tests were also designed to determine the effect of various environmental variables such as temperature, agitation and sludge slurry type on the corrosion behavior of carbon steel. Coupon tests were performed to estimate the corrosion rate during the ECC process, as well as determine any susceptibility to localized corrosion. Electrochemical studies were performed to develop a better understanding of the corrosion mechanism. The tests were performed in 1 wt.% and 2.5 wt.% oxalic acid with HM and PUREX sludge simulants. The following results and conclusions were made based on this testing: (1) In 1 wt.% oxalic acid with a sludge simulant, carbon steel corroded at a rate of less than 25 mpy within the temperature and agitation levels of the test. No susceptibility to localized corrosion was observed. (2) In 2.5 wt.% oxalic acid with a sludge simulant, the carbon steel corrosion rates ranged between 15 and 88 mpy. The most severe corrosion was observed at 75 C in the HM/2.5 wt.% oxalic acid simulant. Pitting and general corrosion increased with the agitation level at this condition. No pitting and lower general corrosion rates were observed with the PUREX/2.5 wt.% oxalic acid simulant. The electrochemical and coupon tests both indicated that carbon steel is more susceptible to localized corrosion in the HM/oxalic acid environment than

  1. A Nationwide Population-Based Study of Corrosive Ingestion in Taiwan: Incidence, Gender Differences, and Mortality

    Directory of Open Access Journals (Sweden)

    Chuan-Mei Chen

    2016-01-01

    Full Text Available Corrosive injury results from the intake of corrosive-acid-based chemicals. However, this phenomenon is limited to a small number of cases and cannot be extrapolated to the epidemiology of corrosive injuries in actual situations. This study focuses on the annual incidence of corrosive injury and its connection to gender, risk factors, and in-hospital mortality. All patients with corrosive injury (ICD-9 947.0–947.3 were identified using a nationwide inpatient sample from 1996 until 2010. Chi-squared tests and multivariate logistic regression were used to examine risk factors of gender differences and in-hospital mortality of corrosive injury. Young adults comprised the majority of patients (71.2%, and mean age was 44.6 ± 20.9 years. Women showed a higher incidence rate of corrosive injuries, age, suicide, psychiatric disorder, and systemic complications compared with men (p<0.001. The present study demonstrated that age (OR = 10.93; 95% CI 5.37–22.27, systemic complications (OR = 5.43; 95% CI 4.61–6.41, malignant neoplasms (OR = 2.23; 95% CI 1.37–3.62, gastrointestinal complications (OR = 2.02; 95% CI 1.63–2.51, chronic disease (OR = 1.30; 95% CI 1.08–1.56, and suicide (OR = 1.23; 95% CI 1.05–1.44 were strongly associated with in-hospital mortality. Educational programs may be helpful for reducing the incidence of ingestion of corrosive chemicals.

  2. A computational study on corrosion inhibition performances of novel quinoline derivatives against the corrosion of iron

    Science.gov (United States)

    Erdoğan, Şaban; Safi, Zaki S.; Kaya, Savaş; Işın, Dilara Özbakır; Guo, Lei; Kaya, Cemal

    2017-04-01

    In this computational study, the adsorption and corrosion inhibition properties of some novel quinoline derivatives namely, 2-amino-7-hydroxy-4-phenyl-1,4-dihydroquinoline-3-carbonitrile (Q1), 2-amino-7-hydroxy-4-(p-tolyl)-1,4-dihydroquinoline-3-carbonitrile (Q2), 2-amino-7-hydroxy-4-(4-methoxyphenyl)-1,4-dihydroquinoline-3-carbonitrile) (Q3) and 2-amino-4-(4-(dimethylamino)phenyl)-7-hydroxy-1,4-dihydroquinoline-3-carbonitrile (Q4) on the corrosion of iron were investigated using quantum chemical and molecular dynamics simulation approaches. Quantum chemical calculations section of the study provides enough calculation and discussion on the relationship between corrosion inhibition and global reactivity descriptors such as EHOMO, ELUMO, HOMO-LUMO energy gap (ΔE), chemical hardness (η), softness (σ), electronegativity (χ), chemical potential (μ), electrophilicity (ω), nucleophilicity (ɛ), electrons transferred from inhibitors to metal surface (ΔN), initial molecule-metal interaction energy (Δψ), total electronic energy (E), the energy change during electronic back-donation process (ΔEb-d). The adsorption behaviors of studied compounds on Fe (110) surface were investigated with the help of molecular dynamics simulation approach. The binding energies calculated on Fe (110) surface of mentioned quinoline derivatives followed the order: Q4 > Q3 > Q2 > Q1. It should be noted that the results obtained in the study are in good agreement with experimental inhibition efficiency results earlier reported.

  3. Influence of pH and Chloride Concentration on the Corrosion Behavior of Unalloyed Copper in NaCl Solution: A Comparative Study Between the Micro and Macro Scales

    Directory of Open Access Journals (Sweden)

    Annemie Adriaens

    2012-11-01

    Full Text Available The effects of pH and chloride concentration on the electrochemical corrosion of copper in aqueous sodium chloride (NaCl media were studied at the micro scale using a microcapillary droplet cell and at the macro scale using a conventional large scale cell. Using an experimental design strategy, electrochemical response surface models of copper versus pH and NaCl concentration were constructed with the minimum number of experiments required. Results show that the electrochemical behavior of copper under corrosive media shows significant differences between the micro and macro scale experiments. At the micro scale, the pit initiation of copper occurs at more negative potentials for high NaCl concentrations and alkaline pH values. Also, the micro scale potentiostatic measurements indicate higher stabilised passive currents at high NaCl concentrations and low (acidic pH values. At the macro scale, the pH is shown to have a greater influence on the corrosion potential. The chloride concentration is the most significant factor in the passive current case while at the micro scale the effect of these two factors on the passive current was found to be the same. The surface morphology of the formed patina on the corroded copper in both micro and macro systems reveal a more significant role of the chloride concentration on the structure and the grain size of the patinas. Finally, micro and macro electrochemical impedance spectroscopy of copper at various NaCl concentrations and pH values demonstrates a different behavior of copper after several potentiodynamic polarization cycles.

  4. Biofilm-growing bacteria involved in the corrosion of concrete wastewater pipes: protocols for comparative metagenomic analyses.

    Science.gov (United States)

    Gomez-Alvarez, Vicente

    2014-01-01

    Advances in high-throughput next-generation sequencing (NGS) technology for direct sequencing of environmental DNA (i.e., shotgun metagenomics) are transforming the field of microbiology. NGS technologies are now regularly being applied in comparative metagenomic studies, which provide the data for functional annotations, taxonomic comparisons, community profile, and metabolic reconstructions. For example, comparative metagenomic analysis of corroded pipes unveiled novel insights on the bacterial populations associated with the sulfur and nitrogen cycle, which may be directly or indirectly implicated in concrete wastewater pipe corrosion. The objective of this chapter is to describe the steps involved in the taxonomic and functional analysis of metagenome datasets from biofilm involved in microbial-induced concrete corrosion (MICC).

  5. Part I. Corrosion studies of continuous alumina fiber reinforced aluminum-matrix composites. Part II. Galvanic corrosion between continuous alumina fiber reinforced aluminum-matrix composites and 4340 steel

    Science.gov (United States)

    Zhu, Jun

    Part I. The corrosion performance of continuous alumina fiber reinforced aluminum-matrix composites (CF-AMCs) was investigated in both the laboratory and field environments by comparing them with their respective monolithic matrix alloys, i.e., pure Al, A1-2wt%Cu T6, and Al 6061 T6. The corrosion initiation sites were identified by monitoring the changes in the surface morphology. Corrosion current densities and pH profiles at localized corrosion sites were measured using the scanning-vibrating electrode technique and the scanning ion-selective electrode technique, respectively. The corrosion damage of the materials immersed in various electrolytes, as well as those exposed in a humidity chamber and outdoor environments, was evaluated. Potentiodynamic polarization behavior was also studied. The corrosion initiation for the composites in 3.15 wt% NaCl occurred primarily around the Fe-rich intermetallic particles, which preferentially existed around the fiber/matrix interface on the composites. The corrosion initiation sites were also caused by physical damage (e.g., localized deformation) to the composite surface. At localized corrosion sites, the buildup of acidity was enhanced by the formation of micro-crevices resulting from fibers left in relief as the matrix corroded. The composites that were tested in exposure experiments exhibited higher corrosion rates than their monolithic alloys. The composites and their monolithic alloys were subjected to pitting corrosion when anodically polarized in the 3.15 wt% NaCl, while they passivated when anodically polarized in 0.5 M Na2SO4. The experimental results indicated that the composites exhibited inferior corrosion resistance compared to their monolithic matrix alloys. Part II. Galvanic corrosion studies were conducted on CF-AMCs coupled to 4340 steel since CF-AMCs have low density and excellent mechanical properties and are being considered as potential jacketing materials for reinforcing steel gun barrels. Coupled and

  6. AFM study of steel corrosion in aqueous solutions in concrete

    Directory of Open Access Journals (Sweden)

    Díaz-Benito, B.

    2011-03-01

    Full Text Available Early corrosion stages are studied in carbon steel by means of a solution simulating that contained in concrete pores. Non-carbonated solution contains 5% NaCl. The atomic force microscopy (AFM technique is used to study material performance after different immersion times (up to 48 h. Obtained data are compared to electrochemical ones (corrosion potential and polarization resistance. Analysis of images and roughness evolution along time shows that steel initially tends to reach passivity, although the passive layer rapidly loses its protective character due to chloride attack.

    Este trabajo estudia los primeros estados de la corrosión de un acero al carbono en una disolución que simula la existente en los poros del hormigón, sin carbonatar, con un 5% de NaCl. Para ello, se ha empleado la técnica de microscopía de fuerza atómica (AFM, estudiando el comportamiento del material tras diferentes tiempos de inmersión, hasta 48 h, en la disolución. Estos datos se comparan con datos electroquímicos (potencial de corrosión y resistencia de polarización. El análisis de las imágenes y la evolución de la rugosidad con el tiempo muestran que el acero tiende inicialmente a pasivarse, pero la capa pasiva pierde rápidamente su carácter protector debido al ataque de los cloruros.

  7. Corrosion study in the chemical air separation (MOLTOX trademark ) process

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Doohee; Wong, Kai P.; Archer, R.A.; Cassano, A.A.

    1988-12-01

    This report presents the results of studies aimed at solving the corrosion problems encountered during operation of the MOLTOX{trademark} pilot plant. These studies concentrated on the screening of commercial and developmental alloys under conditions simulating operation conditions in this high temperature molten salt process. Process economic studies were preformed in parallel with the laboratory testing to ensure that an economically feasible solution would be achieved. In addition to the above DOE co-funded studies, Air Products and Chemicals pursued proprietary studies aimed at developing a less corrosive salt mixture which would potentially allow the use of chemurgically available alloys such as stainless steels throughout the system. These studies will not be reported here; however, the results of corrosion tests in the new less corrosive salt mixtures are reported. Because our own studies on salt chemistry impacts heavily on the overall process and thereby has an influence on the experimental work conducted under this contract, some of the studies discussed here were impacted by our own proprietary data. Therefore, the reasons behind some of the experiments presented herein will not be explained because that information is proprietary to Air Products. 14 refs., 42 figs., 21 tabs.

  8. Long-term corrosion of rebars embedded in aerial and hydraulic binders - Parametric study and first step of modelling

    Energy Technology Data Exchange (ETDEWEB)

    Chitty, Walter-John [CEA, DSM, IRAMIS, Laboratoire Pierre Suee, F-91191 Gif-sur-Yvette cedex (France); Dillmann, Philippe [CEA, DSM, IRAMIS, Laboratoire Pierre Suee, F-91191 Gif-sur-Yvette cedex (France); Institut de Recherches sur les Archeomateriaux, LMC UMR5060 CNRS (France)], E-mail: philippe.dillmann@cea.fr; L' Hostis, Valerie [CEA, DEN, DPC, SCCME, Laboratoire d' Etude du Comportement des Betons et des Argiles, F-91191 Gif-sur-Yvette (France); Millard, Alain [CEA, DEN, DM2S, SEMT, Laboratoire de Modelisation, Systemes et Simulation, F-91191 Gif-sur-Yvette (France)

    2008-11-15

    The prediction of long-term behaviour of reinforced concrete structures involved in the nuclear industry requires a phenomenological modelling of the rebars corrosion processes. Previous analytical characterisation of archaeological artefacts allowed to identify a typical layout constituted of four layers (the metal, the dense product layer, the transformed medium and the binder). Additional experiments leaded to identify the long-term corrosion mechanisms. Following these results, this paper proposes an analytical model of long-term corrosion of rebars embedded in concrete. This modelling is considering the kinetic of oxygen diffusion through the system and its consumption at the metal/dense product layer interface as a function of concrete water saturation degree. Corrosion products thicknesses estimated with the model are then compared to corrosion product thicknesses measured on archaeological artefacts. A parametric study is performed and demonstrates that the oxygen diffusivity and the kinetic constant of the cathodic reaction affect in a wide range the model results.

  9. Corrosion Studies of 2195 Al-Li Alloy and 2219 Al Alloy with Differing Surface Treatments

    Science.gov (United States)

    Danford, M. D.; Mendrek, M. J.

    1998-01-01

    Corrosion studies of 2195 Al-Li and 2219 Al alloys have been conducted using the scanning reference electrode technique (SRET) and the polarization resistance (PR) technique. The SRET was used to study corrosion mechanisms, while corrosion rate measurements were studied with the PR technique. Plates of Al203 blasted, soda blasted and conversion coated 2219 Al were coated with Deft primer and the corrosion rates studied with the EIS technique. Results from all of these studies are presented.

  10. Study of sulphate-reducing bacteria corrosion in the weld joint for API X-70 steel

    Energy Technology Data Exchange (ETDEWEB)

    Flores, J. E.; Patino-Carachure, C.; Alfonso, I.; Rodriguez, J. A.; Rosas, G.

    2012-11-01

    The corrosion behavior originated by sulfate-reducing bacteria (SRB) was studied in two regions of welded API X-70 steel pipeline. The studies were focused on base material (BM) and heat affected zone (HAZ), from the internal region of the pipe. SRB were extracted from oil and grown in a Postgate medium. Corrosion was evaluated at 60 degree centigrade for times between 5 and 64 days. Potentiodynamic polarization curves, obtained by electrochemical techniques, indicated surface activation at short times. Structural and morphological characterizations were carried out by scanning electron microscopy (SEM) and optical microscopy (OM). H{sub 2}S concentration and pH were also measured. Results showed an important increase in the corrosion damage up to 20 days, influenced by the SRB activity, which lead to a maximum of H{sub 2}S (pH minimum). It was found a localized corrosion attack in the HAZ in a higher quantity compared to BM; and the formation of a thin film on the steel surface, originated by corrosion products and bacterial activity. (Author) 15 refs.

  11. Comparative study in the induced corrosion by sulfate reducing microorganisms, in a stainless steel 304L sensitized and a carbon steel API X65; Estudio comparativo de la corrosion inducida por microorganismos sulfatorreductores, en un acero inoxidable 304L sensibilizado y un acero al carbono API X65

    Energy Technology Data Exchange (ETDEWEB)

    Diaz S, A.; Gonzalez F, E.; Arganis J, C.; Luna C, P.; Carapia M, L. [ININ, Carretera Mexico-Toluca Km. 36.5, 52045 Estado de Mexico (Mexico)]. e-mail: ads@nuclear.inin.mx

    2004-07-01

    In spite of the operational experience related with the presence of the phenomenon of microbiological corrosion (MIC) in industrial components, it was not but until the decade of the 80 s when the nuclear industry recognized its influence in some systems of Nuclear Generating Power plants. At the moment, diverse studies that have tried to explain the generation mechanism of this phenomenon exist; however, they are even important queries that to solve, especially those related with the particularities of the affected metallic substrates. Presently work, the electrochemical behavior of samples of stainless steel AISI 304L sensitized is evaluated and the carbon steel APIX65, before the action of sulfate reducing microorganisms low the same experimental conditions; found that for the APIX65 the presence of this type of bacteria promoted the formation of a stable biofilm that allowed the maintenance of the microorganisms that damaged the material in isolated places where stings were generated; while in the AISI 304L, it was not detected damage associated to the inoculated media. The techniques of Resistance to the Polarization and Tafel Extrapolation, allowed the calculation of the speed of uniform corrosion, parameter that doesn't seem to be influenced by the presence of the microorganisms; while that noise electrochemical it distinguished in real time, the effect of the sulfate reducing in the steel APIX65. (Author)

  12. Development of Zn-SiC composite coatings: Electrochemical corrosion studies

    Directory of Open Access Journals (Sweden)

    Mudigere Krishnegowda Punith Kumar

    2015-03-01

    Full Text Available The Zn-SiC composite coatings were fabricated by using sulphate plating bath dispersed with 1, 2 and 3 g L-1 of 64.28 nm SiC nanoparticles. Appreciable influence on morphology and microstructure was observed in scanning electron microscopy, X-ray diffraction spectroscopy and texture co-efficient calculations for SiC incorporated zinc coatings. The electrochemical corrosion behavior of zinc and Zn-SiC composite coatings was studied by potentiodynamic polarization and electrochemical impedance analysis. Significant reduction in corrosion current and corrosion rate with increased charge transfer resistance was noticed for composite coatings. The SiC incorporated zinc coatings shown improved micro-hardness property to pure zinc coating. The properties of Zn-SiC composite coatings were compared with that of pure zinc coating.

  13. Wear and Corrosion Study of Sputtered Zirconium thin films on SS316L for Windmill Application

    Directory of Open Access Journals (Sweden)

    Arunkumar N

    2015-05-01

    Full Text Available The Aim of this study is to observe the Wear and Corrosion behavior of Zirconium coated 316L stainless steel. After polishing, SS316L was coated with Zirconium employing DC sputtering process (a technique of physical vapor deposition.Structure characterization techniques including Scanning Electron Microscope (SEM and X-Ray Diffraction (XRD were utilized to investigate the microstructure and crystallinity of the coating. Salt spray test was performed by spraying Sodium chloride in order to determine corrosion resistance behavior of the coated sample. Pin on disc wear test was performed by hardened and tempered EN31 steel pin in order to determine and compare the Wear resistance behavior of Coated and uncoated samples. The Objective is to recommend the zirconium coated Stainless steel SS316L can be a choice for Off-shore wind mills where the shafts undergo Wear and corrosion problems.

  14. Review of studies on corrosion of magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    ZENG Rong-chang; ZHANG jin; HUANG Wei-jiu; W. DIETZEL; K. U. KAINER; C. BLAWERT; KE Wei

    2006-01-01

    This review provided some recent progress of the research on corrosion mechanisms of magnesium and its alloys and a basis for follow-on research. Galvanic corrosion,pitting corrosion,intergranular corrosion (IGC),filiform corrosion,crevice corrosion,stress corrosion cracking (SCC),and corrosion fatigue (CF) were discussed. The influence of metallurgical factors such as alloying elements,microstructure and secondary phases,processing factors such as heat treatment and weld,and environmental factors including temperature,relative humidity,solution pH values and concentration on corrosion were discussed. In particular,a mechanism of pitting corrosion caused by AlMn particles was proposed. The corrosion properties of AZ91D weld material were investigated.

  15. A STUDY OF CORROSION AND STRESS CORROSION CRACKING OF CARBON STEEL NUCLEAR WASTE STORAGE TANKS

    Energy Technology Data Exchange (ETDEWEB)

    BOOMER, K.D.

    2007-08-21

    The Hanford reservation Tank Farms in Washington State has 177 underground storage tanks that contain approximately 50 million gallons of liquid legacy radioactive waste from cold war plutonium production. These tanks will continue to store waste until it is treated and disposed. These nuclear wastes were converted to highly alkaline pH wastes to protect the carbon steel storage tanks from corrosion. However, the carbon steel is still susceptible to localized corrosion and stress corrosion cracking. The waste chemistry varies from tank to tank, and contains various combinations of hydroxide, nitrate, nitrite, chloride, carbonate, aluminate and other species. The effect of each of these species and any synergistic effects on localized corrosion and stress corrosion cracking of carbon steel have been investigated with electrochemical polarization, slow strain rate, and crack growth rate testing. The effect of solution chemistry, pH, temperature and applied potential are all considered and their role in the corrosion behavior will be discussed.

  16. Comparative Calibration of Corrosion Measurements Using K-Nearest Neighbour Based Techniques

    Directory of Open Access Journals (Sweden)

    Hamed Yaman

    2016-01-01

    Full Text Available Every measuring equipment or inspection tool is known to have its own accuracy, which may affect the reliability of its measurements. This includes oil and gas pipeline corrosion defects measurements. The inspection tolerance occurred in the measurements should be treated carefully for each equipment to prevent misinterpretation of the data which could lead to incorrect assessment. This paper presents a comparison between two K-Nearest Neighbour (KNN interpolation techniques used to calibrate corrosion measurements collected by Magnetic Flux Leakage Intelligent Pig (MFL-IP with the readings of Ultrasonic Testing (UT scan device. The comparison has relied on the position of the interpolators, the weight sequence, and the error in the final enhanced metrics compared to the original measurements. Both techniques have the potential to calibrate and enhance IP measurements, with relative advantage for one technique in reducing over fitting problem. This enhancement will be used to improve the integrity assessment report that depends on the disturbed corrosion metrics of oil and gas pipelines, to decide whether the pipeline is fit for service or needs certain maintenance.

  17. Corrosion studies on casing steel in CO2 storage environments

    NARCIS (Netherlands)

    Zhang, X.; Zevenbergen, J.F.; Benedictus, T.

    2013-01-01

    The corrosion behavior of casing steel N80 in brine plus CO2 was studied in autoclave to simulate the CO2 storage environment. The brine solution used in the study contained 130 g/l NaCl, 22.2 g/l CaCl2 and 4 g/l MgCl2. The CO2 was charged in the autoclave at different pressures (60, 80 and 100 bar)

  18. Corrosion studies on casing steel in CO2 storage environments

    NARCIS (Netherlands)

    Zhang, X.; Zevenbergen, J.F.; Benedictus, T.

    2013-01-01

    The corrosion behavior of casing steel N80 in brine plus CO2 was studied in autoclave to simulate the CO2 storage environment. The brine solution used in the study contained 130 g/l NaCl, 22.2 g/l CaCl2 and 4 g/l MgCl2. The CO2 was charged in the autoclave at different pressures (60, 80 and 100 bar)

  19. Laser Raman Spectroscopy in studies of corrosion and electrocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Melendres, C.A.

    1988-01-01

    Laser Raman Spectroscopy (LRS) has become an important tool for the in-situ structural study of electrochemical systems and processes in recent years. Following a brief introduction of the experimental techniques involved in applying LRS to electrochemical systems, we survey the literature for examples of studies in the inhibition of electrode reactions by surface films (e.g., corrosion and passivation phenomena) as well as the acceleration of reactions by electro-sorbates (electrocatalysis). We deal mostly with both normal and resonance Raman effects on fairly thick surface films in contrast to surface-enhanced Raman investigations of monolayer adsorbates, which is covered in another lecture. Laser Raman spectroelectrochemical studies of corrosion and film formation on such metals as Pb, Ag, Fe, Ni, Co, Cr, Au, stainless steel, etc. in various solution conditions are discussed. Further extension of the technique to studies in high-temperature and high-pressure aqueous environments is demonstrated. Results of studies of the structure of corrosion inhibitors are also presented. As applications of the LRS technique in the area of electrocatalysis, we cite studies of the structure of transition metal macrocyclic compounds, i.e., phthalocyanines and porphyrins, used for catalysis of the oxygen reduction reaction. 104 refs., 20 figs.

  20. A comparative study of the inhibition effects of benzotriazole and 6-aniline-1,3,5-triazine-2,4-dithiol monosodium salt on the corrosion of copper by potentiodynamic polarization, AC impedance and surface-enhanced Raman spectroscopic techniques

    Science.gov (United States)

    Zhou, Guoding; Cai, Shengmin; Song, Liqun; Yang, Huaquan; Fujishima, A.; Ibrahim, A.; Lee, Y. G.; Loo, B. H.

    1991-11-01

    The inhibition effects of benzotriazole (BTA) and 6-aniline-1,3,5-triazine-2,4-dithiol (ATD) monosodium salt on copper corrosion have been studied by the potentiodynamic polarization, AC impedance and surface-enhanced Raman spectroscopic techniques. The polarization resistance Rp increases with the concentration of either BTA or ATD. From the plots of the phase shift θ versus logarithm of the frequency, it is found that θ is close to 90° after the copper electrode is immersed for a long period of time in BTA-containing solution which indicates the behavior of an ideal capacitor. In ATD-containing solutions, θ is close to 45 ° which shows the appearance of a Warburg impedance for a diffusion process. Surface-enhanced Raman spectroscopic studies of the competitive adsorption of BTA and ATD on copper surfaces indicate that BTA adsorbs better than ATD. Based on these results, it is concluded that the inhibition action of BTA is better than that of ATD.

  1. A study of microbial population dynamics associated with corrosion rates influenced by corrosion control materials

    NARCIS (Netherlands)

    Chang, Yu Jie; Hung, Chun Hsiung; Lee, Jyh Wei; Chang, Yi Tang; Lin, Fen Yu; Chuang, Chun Jie

    2015-01-01

    This research aims to analyze the variations of microbial community structure under anaerobic corrosive conditions, using molecular fingerprinting method. The effect of adding various materials to the environment on the corrosion mechanism has been discussed. In the initial experiment, sulfate-re

  2. A study of microbial population dynamics associated with corrosion rates influenced by corrosion control materials

    NARCIS (Netherlands)

    Chang, Yu Jie; Hung, Chun Hsiung; Lee, Jyh Wei; Chang, Yi Tang; Lin, Fen Yu; Chuang, Chun Jie

    2015-01-01

    This research aims to analyze the variations of microbial community structure under anaerobic corrosive conditions, using molecular fingerprinting method. The effect of adding various materials to the environment on the corrosion mechanism has been discussed. In the initial experiment,

  3. Corrosion studies of LiH thin films

    Science.gov (United States)

    Tonks, J. P.; King, M. O.; Galloway, E. C.; Watts, J. F.

    2017-02-01

    Thin films of LiH and its corrosion products were studied using temperature programmed decomposition (TPD), x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Thin films were grown on Ni(100) in an ultra high vacuum system using an electron beam evaporator. Characteristic Li KLL AES peaks were identified for Li, LiH, Li2O and LiOH which facilitated identification of thin film composition. XPS of the O 1s region revealed three distinct chemical shifts which were attributed to Li2O, LiOH and chemisorbed H2O. We show that exposing LiH to very low H2O partial pressures results in formation of LiOH/Li2O domains on LiH. We also show that these XPS peaks can be linked to reaction mechanisms in the TPD profiles. TPD traces have been explicitly modelled to determine the activation energies of the reactions and compare favourably with previous measurements on bulk LiH samples.

  4. Corrosion processes in quantized semiconductor colloids studied by pulse radiolysis

    Energy Technology Data Exchange (ETDEWEB)

    Nenadovic, M.T.; Nedeljkovic, J.M.; Micic, O.I.

    1987-04-01

    Electron-transfer reactions from different electron donors to PbSe colloids with diameter size less than 5 nm were studied by pulse-radiolysis techniques. Colloidal particles accept electrons from redox couples whose redox potentials are more negative than -0.8 V (vs. NHE). The optical properties of injected electrons show formation of Pb/sup +/ in bulk semiconductor after 1 ms and then reduction to Pb/sup 0/ in a second slower step ca. 10 s after electron injection. This cathodic corrosion process is also the dominant process during illumination of the colloids in the presence of hole scavengers. The photoreductive corrosion can be partially suppressed in the presence of an electron acceptor. Reduction reactions that cannot occur in bulk materials can occur in sufficiently small particles. Other quantized metal selenides show similar behaviour. The largest yield of hydrogen was produced with extremely small ZnSe colloids.

  5. Corrosion cast study of the canine hepatic veins.

    Science.gov (United States)

    Uršič, M; Vrecl, M; Fazarinc, G

    2014-11-01

    This study presents a detailed description of the distribution, diameters and drainage patterns of hepatic veins on the basis of the corrosion cast analysis in 18 dogs. We classified the hepatic veins in three main groups: the right hepatic veins of the caudate process and right lateral liver lobe, the middle hepatic veins of the right medial and quadrate lobes and the left hepatic veins of both left liver lobes and the papillary process. The corrosion cast study showed that the number of the veins in the Nomina Anatomica Veterinaria and most anatomical textbooks is underestimated. The number of various-sized hepatic veins of the right liver division ranged from 3 to 5 and included 1 to 4 veins from the caudate process and 2 to 4 veins from the right lateral liver lobe. Generally, in all corrosion casts, one middle-sized vein from the right part of the right medial lobe, which emptied separately in the caudal vena cava, was established. The other vein was a large-sized vein from the remainder of the central division, which frequently joined the common left hepatic vein from the left liver lobes. The common left hepatic vein was the largest of all the aforementioned hepatic veins.

  6. FEBEX Project Post-mortem Analysis: Corrosion Study

    Energy Technology Data Exchange (ETDEWEB)

    Madina, V.; Azkarate, I.

    2004-07-01

    The partial dismantling of the FEBEX in situ test was carried out during de summer of 2002, following 5 years of continuous heating. The operation included the demolition of the concrete plug and the removal of the section of the test corresponding to the first heater. A large number of samples from all types of materials have been taken during the dismantling for subsequent analysis. Part of the samples collected were devoted to the analysis of the corrosion processes occurred during the first operational phase of the test. These samples comprised corrosion coupons from different metals installed for that purpose, sensors retrieved during the dismantling that were found severely corroded and bentonite in contact with those sensors. In addition, a corrosion study was performed on the heater extracted and on one section of liner surrounding it. All the analyses were carried out by the Fundacion INASMET (Spain). This report describes, in detail the studies carried out the different materials and the obtained results, as well as the drawn conclusions. (Author)

  7. Electrochemical study of corrosion inhibition of stainless steel in phosphoric medium

    Energy Technology Data Exchange (ETDEWEB)

    Hnini, K.; Chtaini, A. [Laboratoire d' Electrochimie et de Bio Corrosion, Faculte des Sciences et Techniques, Beni-Mellal (Morocco); Khouili, M.; Elbouadili, A. [Laboratoire de Chimie Organique et Analytique, Faculte des Sciences et Techniques, Beni-Mellal (Morocco)

    2004-07-01

    The corrosion of metals represents a terrible waste of both natural resources and money, the failure of some stainless steel resulting from pitting corrosion is some times considered a technological problem, consequently, much effort has been expended in attempting to understand and overcome the corrosion therefore, many stainless steel/ environment combinations have been studied. The use of heterocyclic compounds as inhibitors is one of the most practical methods for protection against corrosion in acidic media. In continuation of our work on development of macrocyclic compounds as corrosion inhibitors we report in our study the corrosion inhibiting behaviour of organic compound Methoxy-2-Allyl-4 Phenol (MAP) containing coordinating and conjugation groups, at three forms (natural, polymerized and chemically treated) on the corrosion of stainless steel in phosphoric acid. This study focused on the comparison for corrosion inhibition proprieties of these different applications using potentiodynamic polarization, electrochemical impedance spectroscopy and SEM. The specimen was evaluated to determine change in his corrosion potential and resistance polarization; These MAP products have exhibited corrosion inhibition by maintaining a high resistance polarization (low corrosion rate) in each application. These results reveal that this compound is efficient inhibitor in all forms; the most inhibition efficiency is obtained with polymerized form. To further evaluate the test data, the steel surfaces were analyzed using scanning electron microscopy, SEM observations of surface treated concrete confirmed presence of inhibitor on the steel surfaces. (authors)

  8. ALTERNATIVE AND ENHANCED CHEMICAL CLEANING: CORROSION STUDIES RESULTS: FY2010

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B.

    2010-09-29

    Due to the need to close High Level Waste storage tanks, chemical cleaning methods are needed for the removal of sludge heel materials remaining at the completion of mechanical tank cleaning efforts. Oxalic acid is considered the preferred cleaning reagent for heel dissolution of iron-based sludge. However, the large quantity of chemical reagents added to the tank farm from oxalic acid based cleaning has significant downstream impacts. Optimization of the oxalic acid cleaning process can potentially reduce the downstream impacts from chemical cleaning. To optimize oxalic acid usage, a detailed understanding of the chemistry of oxalic acid based sludge dissolution is required. Additionally, other acidic systems may be required for specific waste components that have low solubility in oxalic acid, and as a means to reduce oxalic acid usage in general. Electrochemical corrosion studies were conducted with 1 wt. % oxalic acid at mineral acid concentrations above and below the optimal conditions for this oxalic acid concentration. Testing environments included pure reagents, pure iron and aluminum phases, and sludge simulants. Mineral acid concentrations greater than 0.2 M and temperatures greater than 50 C result in unacceptably high corrosion rates. Results showed that manageable corrosion rates of carbon steel can be achieved at dilute mineral acid concentrations (i.e. less than 0.2 M) and low temperatures based on the contact times involved. Therefore, it is recommended that future dissolution and corrosion testing be performed with a dilute mineral acid and a less concentrated oxalic acid (e.g., 0.5 wt.%) that still promotes optimal dissolution. This recommendation requires the processing of greater water volumes than those for the baseline process during heel dissolution, but allows for minimization of oxalic acid additions. The following conclusions can be drawn from the test results: (1) In both nitric and sulfuric acid based reagents, the low temperature and

  9. Experimental Study on Rebar Corrosion Using the Galvanic Sensor Combined with the Electronic Resistance Technique

    Science.gov (United States)

    Xu, Yunze; Li, Kaiqiang; Liu, Liang; Yang, Lujia; Wang, Xiaona; Huang, Yi

    2016-01-01

    In this paper, a new kind of carbon steel (CS) and stainless steel (SS) galvanic sensor system was developed for the study of rebar corrosion in different pore solution conditions. Through the special design of the CS and SS electronic coupons, the electronic resistance (ER) method and zero resistance ammeter (ZRA) technique were used simultaneously for the measurement of both the galvanic current and the corrosion depth. The corrosion processes in different solution conditions were also studied by linear polarization resistance (LPR) and the measurements of polarization curves. The test result shows that the galvanic current noise can provide detailed information of the corrosion processes. When localized corrosion occurs, the corrosion rate measured by the ER method is lower than the real corrosion rate. However, the value measured by the LPR method is higher than the real corrosion rate. The galvanic current and the corrosion current measured by the LPR method shows linear correlation in chloride-containing saturated Ca(OH)2 solution. The relationship between the corrosion current differences measured by the CS electronic coupons and the galvanic current between the CS and SS electronic coupons can also be used to evaluate the localized corrosion in reinforced concrete. PMID:27618054

  10. Study on interaction between macrocell and microcell in the early corrosion process of reinforcing steel in concrete

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    An array electrode technique was developed as a novel electrochemical method for studying the interaction between macrocell and microcell in the early corrosion process of reinforcing steel in cement mortar.The corrosion potential and galvanic current of macrocell corrosion of the reinforcing steel in cement mortar were imaged by the array electrode technique during the corrosion initiation and propagation.It was certified that the corrosion macrocell current is closely related with the difference of corrosion potential between the anodic and cathodic areas.The corrosion macrocell and microcell always exist during the corrosion process.The interaction of corrosion macrocell and corrosion microcell of steel in concrete was directly sensed by the array electrode for the first time,and was discussed in terms of corrosion electrochemistry.

  11. Modeling corrosion inhibition efficacy of small organic molecules as non-toxic chromate alternatives using comparative molecular surface analysis (CoMSA).

    Science.gov (United States)

    Fernandez, Michael; Breedon, Michael; Cole, Ivan S; Barnard, Amanda S

    2016-10-01

    Traditionally many structural alloys are protected by primer coatings loaded with corrosion inhibiting additives. Strontium Chromate (or other chromates) have been shown to be extremely effectively inhibitors, and find extensive use in protective primer formulations. Unfortunately, hexavalent chromium which imbues these coatings with their corrosion inhibiting properties is also highly toxic, and their use is being increasingly restricted by legislation. In this work we explore a novel tridimensional Quantitative-Structure Property Relationship (3D-QSPR) approach, comparative molecular surface analysis (CoMSA), which was developed to recognize "high-performing" corrosion inhibitor candidates from the distributions of electronegativity, polarizability and van der Waals volume on the molecular surfaces of 28 small organic molecules. Multivariate statistical analysis identified five prototypes molecules, which are capable of explaining 71% of the variance within the inhibitor data set; whilst a further five molecules were also identified as archetypes, describing 75% of data variance. All active corrosion inhibitors, at a 80% threshold, were successfully recognized by the CoMSA model with adequate specificity and precision higher than 70% and 60%, respectively. The model was also capable of identifying structural patterns, that revealed reasonable starting points for where structural changes may augment corrosion inhibition efficacy. The presented methodology can be applied to other functional molecules and extended to cover structure-activity studies in a diverse range of areas such as drug design and novel material discovery. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Studies on broad spectrum corrosion resistant oxide coatings

    Indian Academy of Sciences (India)

    Someswar Datta

    2001-12-01

    The corrosion resistant oxide coatings, developed and applied by the conventional vitreous enamelling techniques, showed superior resistance to a range of mineral acids at various strengths and temperatures, alkaline solutions, boiling water and chrome plating solutions. These coatings possess considerable abrasion and impact resistance as well as high thermal shock resistance. The properties of the coating system have been studied in detail and found to be strongly dependent on composition and processing parameters. These coatings have been characterized by X-ray diffraction analysis and SEM studies. Some of the coating materials have been found to be biocompatible.

  13. Hot Corrosion Studies of HVOF-Sprayed Coating on T-91 Boiler Tube Steel at Different Operating Temperatures

    Science.gov (United States)

    Bhatia, Rakesh; Singh, Hazoor; Sidhu, Buta Singh

    2013-11-01

    The aim of the present work is to investigate the usefulness of high velocity oxy fuel-sprayed 75% Cr3C2-25% (Ni-20Cr) coating to control hot corrosion of T-91 boiler tube steel at different operating temperatures viz 550, 700, and 850 °C. The deposited coatings on the substrates exhibit nearly uniform, adherent and dense microstructure with porosity less than 2%. Thermogravimetry technique is used to study the high temperature hot corrosion behavior of uncoated and coated samples. The corrosion products of the coating on the substrate are analyzed by using XRD, SEM, and FE-SEM/EDAX to reveal their microstructural and compositional features for the corrosion mechanisms. It is found that the coated specimens have shown minimum weight gain at all the operating temperatures when compared with uncoated T-91 samples. Hence, coating is effective in decreasing the corrosion rate in the given molten salt environment. Oxides and spinels of nickel-chromium may be the reason for successful resistance against hot corrosion.

  14. Electrochemical Corrosion Studies for Modeling Metallic Waste Form Release Rates

    Energy Technology Data Exchange (ETDEWEB)

    Poineau, Frederic [Univ. of Nevada, Las Vegas, NV (United States); Tamalis, Dimitri [Florida Memorial Univ., Miami Gardens, FL (United States)

    2016-08-01

    The isotope 99Tc is an important fission product generated from nuclear power production. Because of its long half-life (t1/2 = 2.13 ∙ 105 years) and beta-radiotoxicity (β⁻ = 292 keV), it is a major concern in the long-term management of spent nuclear fuel. In the spent nuclear fuel, Tc is present as an alloy with Mo, Ru, Rh, and Pd called the epsilon-phase, the relative amount of which increases with fuel burn-up. In some separation schemes for spent nuclear fuel, Tc would be separated from the spent fuel and disposed of in a durable waste form. Technetium waste forms under consideration include metallic alloys, oxide ceramics and borosilicate glass. In the development of a metallic waste form, after separation from the spent fuel, Tc would be converted to the metal, incorporated into an alloy and the resulting waste form stored in a repository. Metallic alloys under consideration include Tc–Zr alloys, Tc–stainless steel alloys and Tc–Inconel alloys (Inconel is an alloy of Ni, Cr and iron which is resistant to corrosion). To predict the long-term behavior of the metallic Tc waste form, understanding the corrosion properties of Tc metal and Tc alloys in various chemical environments is needed, but efforts to model the behavior of Tc metallic alloys are limited. One parameter that should also be considered in predicting the long-term behavior of the Tc waste form is the ingrowth of stable Ru that occurs from the radioactive decay of 99Tc (99Tc → 99Ru + β⁻). After a geological period of time, significant amounts of Ru will be present in the Tc and may affect its corrosion properties. Studying the effect of Ru on the corrosion behavior of Tc is also of importance. In this context, we studied the electrochemical behavior of Tc metal, Tc-Ni alloys (to model Tc-Inconel alloy) and Tc-Ru alloys in acidic media. The study of Tc-U alloys has also been performed in order to better understand the

  15. Corrosion resistance of ERW (Electric Resistance Welded) seam welds as compared to metal base in API 5L steel pipes

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Velasquez, Jorge L.; Godinez Salcedo, Jesus G.; Lopez Fajardo, Pedro [Instituto Politecnico Nacional (IPN), Mexico D.F. (Mexico). Escuela Superior de Ingenieria Quimica e Industrias Extractivas (ESIQIE). Dept. de Ingenieria Metalurgica

    2009-07-01

    The corrosion resistance of ERW seam welds and the base metal in API 5L X70 steel pipes was evaluated by Tafel tests. The procedure was according to ASTM G3 standard. The study was completed with metallographic and chemical characterization of the tested zones, that is, the welded zone and the base metal away of the weld. All tests were made on the internal surface of the pipe in order to assess the internal corrosion of an in-service pipeline made of the API 5L X70 steel. The test solution was acid brine prepared according to NACE Publications 1D182 and 1D196. The results showed that the ERW seam weld corrodes as much as three times faster than the base material. This behavior is attributed to a more heterogeneous microstructure with higher internal energy in the ERW seam weld zone, as compared to the base metal, which is basically a ferrite pearlite microstructure in a normalized condition. This result also indicates that pipeline segments made of ERW steel pipe where the seam weld is located near or at the bottom of the pipe are prone to a highly localized attack that may form channels of metal loss if there is water accumulation at the bottom of the pipeline. (author)

  16. Corrosion inhibition of mild steel in 1 M HCl solution by henna extract: A comparative study of the inhibition by henna and its constituents (Lawsone, Gallic acid, {alpha}-D-Glucose and Tannic acid)

    Energy Technology Data Exchange (ETDEWEB)

    Ostovari, A. [Technical Inspection Engineering Department, Petroleum University of Technology, Abadan (Iran, Islamic Republic of)], E-mail: A.Ostovari@gmail.com; Hoseinieh, S.M.; Peikari, M. [Technical Inspection Engineering Department, Petroleum University of Technology, Abadan (Iran, Islamic Republic of); Shadizadeh, S.R. [Petroleum Engineering Department, Petroleum University of Technology, Abadan (Iran, Islamic Republic of); Hashemi, S.J. [Technical Inspection Engineering Department, Petroleum University of Technology, Abadan (Iran, Islamic Republic of)

    2009-09-15

    The inhibitive action of henna extract (Lawsonia inermis) and its main constituents (lawsone, gallic acid, {alpha}-D-Glucose and tannic acid) on corrosion of mild steel in 1 M HCl solution was investigated through electrochemical techniques and surface analysis (SEM/EDS). Polarization measurements indicate that all the examined compounds act as a mixed inhibitor and inhibition efficiency increases with inhibitor concentration. Maximum inhibition efficiency (92.06%) is obtained at 1.2 g/l henna extract. Inhibition efficiency increases in the order: lawsone > henna extract > gallic acid > {alpha}-D-Glucose > tannic acid. Also, inhibition mechanism and thermodynamic parameters are discussed.

  17. Corrosion Study and Intermetallics Formation in Gold and Copper Wire Bonding in Microelectronics Packaging

    Directory of Open Access Journals (Sweden)

    Christopher Breach

    2013-07-01

    Full Text Available A comparison study on the reliability of gold (Au and copper (Cu wire bonding is conducted to determine their corrosion and oxidation behavior in different environmental conditions. The corrosion and oxidation behaviors of Au and Cu wire bonding are determined through soaking in sodium chloride (NaCl solution and high temperature storage (HTS at 175 °C, 200 °C and 225 °C. Galvanic corrosion is more intense in Cu wire bonding as compared to Au wire bonding in NaCl solution due to the minimal formation of intermetallics in the former. At all three HTS annealing temperatures, the rate of Cu-Al intermetallic formation is found to be three to five times slower than Au-Al intermetallics. The faster intermetallic growth rate and lower activation energy found in this work for both Au/Al and Cu/Al as compared to literature could be due to the thicker Al pad metallization which removed the rate-determining step in previous studies due to deficit in Al material.

  18. Study of corrosion behaviour in saturated bentonite barrier Corroben; Estudio de los productos de corrosion de la capsula y su interaccion con la berrar arcillosa de bentonita Corroben

    Energy Technology Data Exchange (ETDEWEB)

    Azkarate, I.; Insausti, M.; Medina, V.

    2004-07-01

    The corrosion behavior in saturated bentonite of various candidate metallic materials, to be used in the fabrication of containers of high level radioactive waste granite repositories, has been studied in this project. Due to the multi-barrier concept in which the canisters are surrounded by a clay barrier of compacted bentonite blocks, special attention has been paid to the characterization of corrosion products and the interaction between these and the repository sealing bentonite. The following metallic materials have been studied: S355 carbon steel, AISI 316L stainless steel, Cu-ETP electrolytic copper and Cu30Ni alloy. Samples of the alloys have been embedded in saturated bentonite to a water content of 25%, and compacted. The obtained pastilles have been introduced in autoclaves and tested at different temperatures and times ranging from one to 18 months. Once tests have concluded, several parameters have been evaluated: corrosion morphology, general corrosion rates calculated by gravimetric methods, nature and composition of the corrosion products and penetration of the corrosion products into the bentonite. Experimental data obtained are used to developed models of the corrosion behavior of canisters under disposal conditions. Results show that S355 carbon steel has suffered the highest general corrosion attack, with average corrosion rates of 10 per year and maximum penetration of 100 measured in specimens tested at 75C during 18 months. The most common analyzed corrosion product has been siderite, FeCO3. Formation of siderite, in the test conditions, effectively passivated the steel because of its stable and adherent feature. In test carried out at 25 and 5 C, sulfur rich corrosion products are observed, thus indicating a microbiologically corrosion phenomena due to the metabolic activity of bacteria present in the bentonite. No appreciable general corrosion rates, nor sensitivity to localized corrosion, has been observed in the AISI 316L stainless steel

  19. STUDY CONCERNING THE CORROSIVE ACTIVITY PROPERTIES OF MONATOMIC ALCOHOL-GASOLINE BLENDS

    Directory of Open Access Journals (Sweden)

    Valerian Cerempei

    2011-12-01

    Full Text Available The paper studies the corrosive activity of the monatomic alcohol (ethanol, butanol - gasoline mixtures on the materials from which the internal combustion engines are made. The corrosive influence of these blends was determined in dependence of their composition. It was established that the addition of butanol and triethylamine in the ethanol-gasoline mixture essentially reduces the corrosive activity of this mixture.

  20. Study of corrosion between a titanium implant and dental alloys.

    Science.gov (United States)

    Reclaru, L; Meyer, J M

    1994-06-01

    The infiltration of saliva into the multi-metallic structures on titanium implants brings different types of alloys into temporary or permanent contact. In this way a galvanic cell is established as a result of their potential difference. The galvanic cell phenomenon is compounded by another type of corrosion resulting from the geometry of the assembly: localized crevice corrosion. Fifteen galvanic couples (Ti/gold-based alloys, Ti/palladium-based alloy and Ti/non-precious alloys) were studied. Various electrochemical parameters (Ecorr, Ecommon, Ecouple corr, Ecrevice, icorr, icouple corr and Tafel slopes) were analysed. The galvanic currents measured are of the same order of magnitude (except Ti/stainless steel). They remain low. Application of the mixed-potential theory shows that titanium in coupling with the alloys studied will be under either cathodic or anodic control. According to the results obtained, an alloy that is potentially usable for superstructures in a galvanic coupling with titanium must fulfil a certain number of parameters: in a coupling, titanium must have a weak anodic polarization; the current generated by the galvanic cell must also be weak; the crevice potential must be markedly higher than the common potential.

  1. Study of corrosion erosion behaviour of stainless alloys in industrial phosphoric acid medium

    Science.gov (United States)

    Guenbour, Abdellah; Hajji, Mohamed-Adil; Jallouli, El Miloudi; Bachir, Ali Ben

    2006-12-01

    The corrosion and corrosion-abrasion resistance of some stainless steels in industrial phosphoric acid 30% P 2O 5 has been studied using electrochemical techniques. The corrosion rate of materials increases with the increase of temperature. Alloys which contain chromium, molybdenum and nitrogen in sufficient quantities present the best behaviour. In the abrasion-corrosion conditions, the experimental device set up allowed to follow continually samples electrochemical behaviour. Under dynamic conditions and without solid particles, the increase of acid projection speed has no effect on the alloys corrosion behaviour. The adding of abrasive leads to a general increase of corrosion rate and to a decrease of material resistance. Under these conditions, materials attack is controlled by synergistic effect between the abrasion and the impurities. The cast 30% Cr shows good resistance according to his high chromium content.

  2. Study of surface interactions of ionic liquids with aluminium alloys in corrosion and erosion-corrosion processes

    Energy Technology Data Exchange (ETDEWEB)

    Bermudez, Maria-Dolores [Grupo de Ciencia de Materiales e Ingenieria Metalurgica, Departamento de Ingenieria de Materiales y Fabricacion, Universidad Politecnica de Cartagena, C/ Doctor Fleming s/n, Campus Muralla del Mar, 30202 Cartagena (Spain)]. E-mail: mdolores.bermudez@upct.es; Jimenez, Ana-Eva [Grupo de Ciencia de Materiales e Ingenieria Metalurgica, Departamento de Ingenieria de Materiales y Fabricacion, Universidad Politecnica de Cartagena, C/ Doctor Fleming s/n, Campus Muralla del Mar, 30202 Cartagena (Spain); Martinez-Nicolas, Gines [Grupo de Ciencia de Materiales e Ingenieria Metalurgica, Departamento de Ingenieria de Materiales y Fabricacion, Universidad Politecnica de Cartagena, C/ Doctor Fleming s/n, Campus Muralla del Mar, 30202 Cartagena (Spain)

    2007-06-30

    Surface interactions of alkylimidazolium ionic liquids (ILs) with aluminium alloy Al 2011 have been studied by immersion tests in seven neat ILs [1-n-alkyl-3-methylimidazolium X{sup -} (X = BF{sub 4}; n = 2 (IL1), 6 (IL2), 8 (IL3). X = CF{sub 3}SO{sub 3}; n = 2 (IL4). X = (4-CH{sub 3}C{sub 6}H{sub 4}SO{sub 3}); n = 2 (IL5). X PF{sub 6}; n = 6 (IL6)] and 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide (IL7)]. Immersion tests for Al 2011 have also been carried out in 1 wt.% and 5 wt.% solutions of 1-ethyl,3-methylimidazolium tetrafluoroborate (IL1) in water. No corrosion of Al 2011 by neat ILs is observed. The highest corrosion rate for Al 2011 in water is observed in the presence of a 5 wt.% IL1 due to hydrolysis of the anion with hydrogen evolution and formation of aluminium fluoride. Erosion-corrosion processes have been studied for three aluminium alloys (Al 2011, Al 6061 and Al 7075) in a 90 wt.% IL1 solution in water in the presence of {alpha}-alumina particles. The erosion-corrosion rates are around 0.2 mm/year or lower, and increase with increasing copper content to give a corrosion resistance order of Al 6061 > Al 7075 > Al 2011. Results are discussed on the basis of scanning electron microscopy (SEM) observations, energy dispersive spectroscopy (EDS) analysis, X-ray diffraction (XRD) patterns and X-ray photoelectron spectroscopy (XPS) determinations.

  3. Study of Plant Cordia Dichotoma as Green Corrosion Inhibitor for Mild Steel in Different Acid Media

    Directory of Open Access Journals (Sweden)

    R. Khandelwal

    2011-01-01

    Full Text Available The corrosion inhibition of mild steel using extracts of Cordia dichotoma in different acid media was investigated by mass loss and thermometric methods. The experiments were carried out at 299±0.2 K in presence of different concentrations of dry fruit, leaves and stem extracts of Cordia dichotoma. The results reveal that the alcoholic extracts of Cordia dichotoma is a better corrosion inhibitor than that of toxic chemicals. The fruit extract is more potent than leaves and stem extracts to inhibit the corrosion rate. The study seeks to investigate the possibility of using extracts of Cordia dichotoma as a green corrosion inhibitor for mild steel.

  4. FURTHER DEVELOPMENT OF THE QUALITATIVE ELLIPSOMETRIC TECHNIQUE FOR THE STUDY OF CORROSION PROCESSES UNDER ORGANIC COATINGS

    OpenAIRE

    Ritter, J; Kruger, J.

    1983-01-01

    We describe the further development of an ellipsometric technique used to study corrosion processes under organic coatings. These developments include the ability to (1) detect the effect of different organic coating, (2) distinguish between surface roughening and film growth or dissolution, and (3) study corrosion processes occurring on separate anodic and cathodic sites.

  5. Environmental Considerations in the Studies of Corrosion Resistant Alloys for High-Level Radioactive Waste Containment

    Energy Technology Data Exchange (ETDEWEB)

    Ilevbare, G O; Lian, T; Farmer, J C

    2001-11-26

    The corrosion resistance of Alloy 22 (UNS No.: N06022) was studied in simulated ground water of different pH values and ionic contents at various temperatures. Potentiodynamic polarization techniques were used to study the electrochemical behavior and measure the critical potentials in the various systems. Alloy 22 was found to be resistant to localized corrosion in the simulated ground waters tested.

  6. A prospective study of comparison between Open Gastrojejunostomy and Laparoscopic Assisted Gastrojejunostomy in patients of post corrosive ingestion pyloric stenosis.

    Directory of Open Access Journals (Sweden)

    Samir shah

    2016-03-01

    Results: We observed that benign etiology was more common for GOO (58% compared to malignant cause (42% and post corrosive ingestion pyloric stenosis was most common benign cause(42% of GOO, Pancreatic cancer was most common malignant cause(18.5% of GOO. Corrosive ingestion was more common in younger age group (66% in 15 -30 yr age and female gender(63.34% and mostly as a suicidal attempt(86.66% and most common corrosive agent was sanitary cleansing agent(hydrochloric acid (70%.Postprandial nonbillious vomiting and weight loss were consistent symptom and appeared after 6-8 week of corrosive ingestion and 50% of patient of post corrosive ingestion pyloric stenosis had concomitant esophageal stricture. In present study those patient operated with Lap Assisted Gastrojejunostomy had smaller size of incision, reduce intra operative need of blood transfusion, less post-operative pain and less chance of wound infection, early drain and suture removal and early discharged from hospital with minimal post-operative morbidity and without significant increase in total duration and cost of operation. Conclusion : As compared to Open Gastrojejunostomy, Lap Assisted Gastrojejunostomy is better alternative operative method for pyloric stenosis. [Natl J Med Res 2016; 6(1.000: 48-50

  7. Morphological study of silver corrosion in highly aggressive sulfur environments

    DEFF Research Database (Denmark)

    Minzari, Daniel; Jellesen, Morten Stendahl; Møller, Per

    2011-01-01

    the silicone coating to the interface has resulted in three corrosion types namely: uniform corrosion, conductive anodic filament type of Ag2S growth, and silver migration with subsequent formation of sulfur compounds. Detailed morphological investigation of new and corroded power modules was carried out...

  8. Corrosion Studies of Platinum Nano-Particles for Fuel Cells

    DEFF Research Database (Denmark)

    Shim, Signe Sarah

    The main focus of the present thesis is on corrosion and prevention of corrosion of platinum particles supported on carbon. This is important for instance in connection with start up and shutdown of fuel cells. The degradation mechanism of platinum particles supported on carbon has been...

  9. Study on Microstructure and Slag Corrosion Mechanism of High Chrome Bricks for Gasifier

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Research was focused on slag corrosion mechanism of high chrome bricks used for different types of gasifier by comparing the structure of high chrome bricks for petroleum coke gasifier and water-coal slurry gasifier with slag corroded testing brick and water coal slurry gasifier through Scanning Electron Microscope (SEM) examination and X-ray diffraction. Results show that for high chrome brick used for petroleum coke gasifier, corrosion is mainly caused by Cr2O3 in the brick and V2O5 in molten slag and liquid phase generation at low temperature; for high chrome brick used for water-coal slurry gasifier, corrosion is caused by dissolution of Cr2O3 in molten slag and corrosion of ZrO2. For LIRR-HK95 brick, it performs better petroleum coke corrosion resistance than the others due to the optimal composition and structure.

  10. In-situ electrochemical study of interaction of tribology and corrosion in artificial hip prosthesis simulators.

    Science.gov (United States)

    Yan, Yu; Dowson, Duncan; Neville, Anne

    2013-02-01

    The second generation Metal-on-Metal (MoM) hip replacements have been considered as an alternative to commonly used Polyethylene-on-Metal (PoM) joint prostheses due to polyethylene wear debris induced osteolysis. However, the role of corrosion and the biofilm formed under tribological contact are still not fully understood. Enhanced metal ion concentrations have been reported widely from hair, blood and urine samples of patients who received metal hip replacements and in isolated cases when abnormally high levels have caused adverse local tissue reactions. An understanding of the origin of metal ions is really important in order to design alloys for reduced ion release. Reciprocating pin-on-plate wear tester is a standard instrument to assess the interaction of corrosion and wear. However, more realistic hip simulator can provide a better understanding of tribocorrosion process for hip implants. It is very important to instrument the conventional hip simulator to enable electrochemical measurements. In this study, simple reciprocating pin-on-plate wear tests and hip simulator tests were compared. It was found that metal ions originated from two sources: (a) a depassivation of the contacting surfaces due to tribology (rubbing) and (b) corrosion of nano-sized wear particles generated from the contacting surfaces.

  11. Studies on corrosion protection of laser hybrid welded AISI 316 by laser remelting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Ambat, Rajan; Rasmussen, A.J.

    2005-01-01

    Unlike in autogenous laser welding, hybrid laser welding of stainless steel could introduce grain boundary carbides due to low cooling rates. Formation of grain boundary carbides leads to reduced corrosion properties. Studies have initially been carried out on hybrid laser welding and subsequent ...... regain the corrosion resistance by desensitization....

  12. Quantum Chemical Study on the Corrosion Inhibition of Some Oxadiazoles

    Directory of Open Access Journals (Sweden)

    Hong Ju

    2015-01-01

    Full Text Available Quantum chemical calculations based on DFT method were performed on three nitrogen-bearing heterocyclic compounds used as corrosion inhibitors for the mild steel in acid media to determine the relationship between the molecular structure of inhibitors and inhibition efficiency. The structural parameters, such as energy and distribution of highest occupied molecular orbital (HOMO and lowest unoccupied molecular orbital (LUMO, the charge distribution of the studied inhibitors, the absolute electronegativity (χ values, and the fraction of electrons (ΔN transfer from inhibitors to mild steel were also calculated and correlated with inhibition efficiencies. The results showed that the inhibition efficiency of inhibitors increased with the increase in energy of HOMO and decrease in energy gap of frontier molecular orbital, and the areas containing N and O atoms are most possible sites for bonding the steel surface by donating electrons to the mild steel.

  13. Corrosion Engineering.

    Science.gov (United States)

    White, Charles V.

    A description is provided for a Corrosion and Corrosion Control course offered in the Continuing Engineering Education Program at the General Motors Institute (GMI). GMI is a small cooperative engineering school of approximately 2,000 students who alternate between six-week periods of academic study and six weeks of related work experience in…

  14. Theoretical study of inhibition efficiencies of some amino acids on corrosion of carbon steel in acidic media: green corrosion inhibitors.

    Science.gov (United States)

    Dehdab, Maryam; Shahraki, Mehdi; Habibi-Khorassani, Sayyed Mostafa

    2016-01-01

    Inhibition efficiencies of three amino acids [tryptophan (B), tyrosine (c), and serine (A)] have been studied as green corrosion inhibitors on corrosion of carbon steel using density functional theory (DFT) method in gas and aqueous phases. Quantum chemical parameters such as EH OMO (highest occupied molecular orbital energy), E LUMO (lowest unoccupied molecular orbital energy), hardness (η), polarizability ([Formula: see text]), total negative charges on atoms (TNC), molecular volume (MV) and total energy (TE) have been calculated at the B3LYP level of theory with 6-311++G** basis set. Consistent with experimental data, theoretical results showed that the order of inhibition efficiency is tryptophan (B) > tyrosine (C) > serine (A). In order to determine the possible sites of nucleophilic and electrophilic attacks, local reactivity has been evaluated through Fukui indices.

  15. XPS study of the corrosion resisting composite alloying layer obtained by double glow plasma with the brush plating Ni interlayer

    Institute of Scientific and Technical Information of China (English)

    Jiang Xu; Xishan Xie; Zhong Xu; Wenjin Liu

    2004-01-01

    The Ni-Cr-Mo-Cu multi-element surface alloying with the electric brush plating Ni interlayer on the low carbon steel substrate has been investigated. By the electrochemical method in 3.5% (mass fraction) NaC1 solution, the corrosion resistance of the composite alloying layer and single alloying layer is determined. The experimental results show that the corrosion resistance of the composite alloying layer is obviously better than that of the single alloying layer. The structure and composition of passive films formed on the two kinds of alloyed layers after electrochemical tests in 3.5% NaC1 solution have been studied using X-ray photoelectron spectroscopy (XPS). It is concluded that the double glow plasma surface alloying of low carbon steel with the electric brush plating Ni interlayer is an appropriate technique to enhance the corrosion resistance compared with the single double glow surface alloying.

  16. Studying Cu Alloy Corrosion Products in Cooling Liquid

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effect of cooiing liquid used for heat exchangers on the Cu alloy corrosion products has been examined using potential-time measurements under applied current condition (anodizing), potentiodynamic polarization, X-ray diffraction (XRD) and infrared spectroscopy (IR). The corrosion products formed on the Cu alloy surface during anodizing, are Cu2O, Cu2(OH)3CI, and Cu2S. NaCI is detected in the corrosion products. The film formation depends on the applied current and the shift of potential to nobler direction indicates its formation progress.

  17. Effect of corrosion on flexural bond strength

    Directory of Open Access Journals (Sweden)

    Akshatha Shetty

    2014-09-01

    Full Text Available Corrosion is one of the main causes affecting durability of structures. Corrosion effects on structures cannot be ignored and replaced. To understand the performance of structures there is a need to study the rate at which different corrosion levels occur. Hence the present investigation has been taken up to study the behaviour of NBS (National Bureau of Standard beam specimens made up of Ordinary Portland Cement (OPC and Portland Pozzolona Cement (PPC concrete matrix were subjected to accelerated corrosion for different corrosion levels of 2.5 % to 10 % at 2.5 % interval. Results are compared with those for control beam specimen. It is observed that bond stress value decreases with the increase in corrosion levels. Also corrosion leads to the decline of load carrying capacity.

  18. 3D study of intermetallics and their effect on the corrosion morphology of rheocast aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Mingo, B. [Departamento de Ciencia de Materiales, Facultad de Ciencias Químicas, Universidad Complutense, 28040, Madrid (Spain); Arrabal, R., E-mail: rarrabal@ucm.es [Departamento de Ciencia de Materiales, Facultad de Ciencias Químicas, Universidad Complutense, 28040, Madrid (Spain); Pardo, A.; Matykina, E. [Departamento de Ciencia de Materiales, Facultad de Ciencias Químicas, Universidad Complutense, 28040, Madrid (Spain); Skeldon, P. [Corrosion and Protection Group, School of Materials, The University of Manchester, Manchester M13 9PL (United Kingdom)

    2016-02-15

    In the present study, the effect of heat treatment T6.1 on the microstructure and corrosion behaviour of rheocast aluminium alloy A356 is investigated on the basis of 2D/3D characterization techniques and electrochemical and SKPFM measurements. Heat treatment strengthens the α-Al matrix, modifies the intermetallic particles and spheroidizes eutectic Si. These changes do not modify significantly the corrosion behaviour of the alloy. 3D SEM-Tomography clearly shows that the corrosion advances in the shape of narrow paths between closely spaced intermetallics without a major influence of eutectic Si. - Highlights: • T6.1 spheroidizes Si, strengthens the matrix and modifies the intermetallics. • Electrochemical behaviour of untreated and heat-treated alloys is similar. • 3D SEM-Tomography provides additional information on the corrosion morphology. • Corrosion advances as paths between intermetallics with little influence of Si.

  19. Study on the hot corrosion behavior of a cast Ni-base superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.; Guo, J.T.; Zhang, J.; Yuan, C.; Zhou, L.Z.; Hu, Z.Q. [Chinese Academy of Sciences, Shenyang (China). Inst. of Metal Research

    2010-07-01

    Hot corrosion behavior of Nickel-base cast superalloy K447 in 90% Na{sub 2}SO{sub 4} + 10% NaCl melting salt at 850 C and 900 C was studied. The hot corrosion kinetic of the alloy follows parabolic rate law under the experimental conditions. The external layer is mainly Cr{sub 2}O{sub 3} scale which is protective to the alloy, the intermediate layer is the Ti-rich phase, and the internal layer is mainly the international oxides and sulfides. With increased corrosion time and temperature, the oxide scales are gradually dissolved in the molten salt and then precipitate as a thick and non-protective scale. Chlorides cause the formation of volatile species, which makes the oxide scale disintegrate and break off. The corrosion kinetics and morphology examinations tend to support the basic dissolution model for hot corrosion mechanisms. (orig.)

  20. Comparative Packaging Study

    Science.gov (United States)

    Perchonok, Michele; Antonini, David

    2008-01-01

    This viewgraph presentation describes a comparative packaging study for use on long duration space missions. The topics include: 1) Purpose; 2) Deliverables; 3) Food Sample Selection; 4) Experimental Design Matrix; 5) Permeation Rate Comparison; and 6) Packaging Material Information.

  1. STUDY OF THE PROPOLIS EXTRACT AS A CORROSION ...

    African Journals Online (AJOL)

    H. Hachelef

    2017-05-01

    May 1, 2017 ... Keywords: Copper Alloy, Propolis extract, ethylene glycol; Corrosion ... containing multiple bonds and hetero atoms which are effective .... explained by a passivation phenomenon due to the formation of a copper oxide layer.

  2. SRNL SHELF LIFE STUDIES - SCC STUDIES AT ROOM TEMPERTURE [stress corrosion cracking

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J.; Duffey, J.

    2014-11-12

    Phase II, Series 2 corrosion testing performed by the Savannah River National Laboratory (SRNL) for the Department of Energy 3013 container has been completed. The corrosion tests are part of an integrated plan conducted jointly by Los Alamos National Laboratory and the Savannah River Site. SRNL was responsible for conducting corrosion studies in small-scale vessels to address the influence of salt composition, water loading, and type of oxide/salt contact on the relative humidity inside a 3013 container and on the resulting corrosion of Type 304L and 316L stainless steel (304L and 316L). This testing was conducted in two phases: Phase I evaluated a broad spectrum of salt compositions and initial water loadings on the salt mixtures exposed to 304L and 316L and the resulting corrosion; Phase II evaluated the corrosion of 304L at specific water loadings and a single salt composition. During Phase I testing at high initial moisture levels (0.35 to 1.24 wt%)a, the roomtemperature corrosion of 304L exposed to a series of plutonium oxide/chloride salt mixtures ranged from superficial staining to pitting and stress corrosion cracking (SCC). 304L teardrop coupons that exhibited SCC were directly exposed to a mixture composed of 98 wt % PuO2, 0.9 wt % NaCl, 0.9 wt % KCl, and 0.2 wt % CaCl2. Cracking was not observed in a 316L teardrop coupon. Pitting was also observed in this environment for both 304L and 316L with depths ranging from 20 to 100 μm. Neither pitting nor SCC was observed in mixtures with a greater chloride salt concentration (5 and 28 wt%). These results demonstrated that for a corrosive solution to form a balance existed between the water loading and the salt chloride concentration. This chloride solution results from the interaction of loaded water with the hydrating CaCl2 salt. In Phase II, Series 1 tests, the SCC results were shown to be reproducible with cracking occurring in as little as 85 days. The approximate 0.5 wt% moisture level was found to

  3. Study of biofuels corrosiveness; Estudo da corrosividade de biocombustiveis

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Rafaela da Conceicao; Branco, Lucas da Paz Nogueira; Guimaraes, Maria Jose de Oliveria Cavalcanti; Seidl, Peter Rudolf [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica

    2012-07-01

    The replacement of crude oil derivatives with biofuels is part of an energy strategy, in which efficiency and conservation should play a leading role. The renewable nature of biodiesel is based in the fact that it is derived from raw materials from agricultural activities, instead of petroleum. Thinking about the increasingly production of biodiesel and its storage to make the proper mixtures, the corrosion of biodiesel tanks can occur over time. The copper corrosion test is used as the standard method for biodiesel corrosivity, however it is designed for diesel fuel from petroleum. Petrodiesel contains sulfur, which attacks the copper alloys. Since biodiesel is free of this element, it should be characterized in a different way. This work intends to analyze existing methodologies in order to evaluate the corrosivity of biodiesel. A literature search was performed in Web of Science database, selecting keywords for a comprehensive search. For the final analysis, a selection of papers classified according to publication year, country and main subject covered was used. Research on biofuels corrosivity is recent and major countries where published (USA, Malaysia and Brazil) which have advantages in terms of size and production of oil seeds. Biodiesel is more corrosive than petroleum diesel, but there is no sufficient evidences as to verify if the level of corrosion found in biodiesel is within acceptable limits for automotive components. Ferrous alloys are more resistant to biodiesel attack than non-ferrous alloys. Among non-ferrous alloys, copper and lead alloys are the most vulnerable, followed by aluminum. It is necessary to develop appropriate methodologies to determine and characterize the corrosivity of biodiesel on engine parts and alloys used in its manufacture and storage. (author)

  4. A facility for studying irradiation accelerated corrosion in high temperature water

    Science.gov (United States)

    Raiman, Stephen S.; Flick, Alexander; Toader, Ovidiu; Wang, Peng; Samad, Nassim A.; Jiao, Zhijie; Was, Gary S.

    2014-08-01

    A facility for the study of irradiation accelerated corrosion in high temperature water using in situ proton irradiation has been developed and validated. A specially designed beamline and flowing-water corrosion cell added to the 1.7 MV tandem accelerator at the Michigan Ion Beam Laboratory provide the capability to study the simultaneous effects of displacement damage and radiolysis on corrosion. A thin sample serves as both a “window” into the corrosion cell through which the proton beam passes completely, and the sample for assessing irradiation accelerated corrosion. The facility was tested by irradiating stainless steel samples at beam current densities between 0.5 and 10 μA/cm2 in 130 °C and 320 °C deaerated water, and 320 °C water with 3 wppm H2. Increases in the conductivity and dissolved oxygen content of the water varied with the proton beam current, suggesting that proton irradiation was accelerating the corrosion of the sample. Conductivity increases were greatest at 320 °C, while DO increases were highest at 130 °C. The addition of 3 wppm H2 suppressed DO below detectable levels. The facility will enable future studies into the effect of irradiation on corrosion in high temperature water with in situ proton irradiation.

  5. Corrosion studies in fuel element reprocessing environments containing nitric acid

    Energy Technology Data Exchange (ETDEWEB)

    Beavers, J A; White, R R; Berry, W E; Griess, J C

    1982-04-01

    Nitric acid is universally used in aqueous fuel element reprocessing plants; however, in the processing scheme being developed by the Consolidated Fuel Reprocessing Program, some of the equipment will be exposed to nitric acid under conditions not previously encountered in fuel element reprocessing plants. A previous report presented corrosion data obtained in hyperazeotropic nitric acid and in concentrated magnesium nitrate solutions used in its preparation. The results presented in this report are concerned with the following: (1) corrosion of titanium in nitric acid; (2) corrosion of nickel-base alloys in a nitric acid-hydrofluoric acid solution; (3) the formation of Cr(VI), which enhances corrosion, in nitric acid solutions; and (4) corrosion of mechanical pipe connectors in nitric acid. The results show that the corrosion rate of titanium increased with the refreshment rate of boiling nitric acid, but the effect diminished rapidly as the temperature decreased. The addition of iodic acid inhibited attack. Also, up to 200 ppM of fluoride in 70% HNO/sub 3/ had no major effect on the corrosion of either titanium or tantalum. In boiling 8 M HNO/sub 3/-0.05 M HF, Inconel 671 was more resistant than Inconel 690, but both alloys experienced end-grain attack. In the case of Inconel 671, heat treatment was very important; annealed and quenched material was much more resistant than furnace-cooled material.The rate of oxidation of Cr(III) to Cr(VI) increased significantly as the nitric acid concentration increased, and certain forms of ruthenium in the solution seemed to accelerate the rate of formation. Mechanical connectors of T-304L stainless steel experienced end-grain attack on the exposed pipe ends, and seal rings of both stainless steel and a titanium alloy (6% Al-4% V) underwent heavy attack in boiling 8 M HNO/sub 3/.

  6. Estudio comparativo de la evaluación a la corrosión de recubrimientos de CrN y CrN/Cr con recubrimientos de cromo electrodepositado y pinturas tipo epoxy A comparative study of corrosion resistance in CrN and CrN/Cr coatings, electrodeposited chromium and epoxy paints

    Directory of Open Access Journals (Sweden)

    Olaya Florez Jhon Jairo

    2010-12-01

    Full Text Available En este trabajo se compara la resistencia a la corrosión de recubrimientos de CrN y CrN/Cr depositados con el sistema de sputtering con magnetrón desbalanceado (UBM con recubrimientos industriales de Cr y pinturas tipo epoxy. Los recubrimientos UBM fueron optimizados y producidos a temperatura ambiente y con una corriente de descarga de 400 mA. Se utilizó un flujo de Ar de 9 sccm y para la producción de CrN se activó el nitrógeno con un flujo de 3 sccm. Los tiempos de depósito se ajustaron para producir monocapas de CrN y multicapas a escala nanométrica manteniendo un espesor total de 1 μm y un periodo de 100 nm. A los recubrimientos obtenidos se les determinó su microestructura con icroscopia electrónica de barrido (SEM, la textura y fases cristalinas con difracción de rayos X (XRD y espectroscopia infrarroja (IR, y la resistencia a la corrosión se evaluó con ensayos de polarización potenciodinámica utilizando una solución de 0,5M H2SO4 y 0,05M KSCN. En general, las multicapas anométricas mejoraron la resistencia a la corrosión de los aceros inoxidables, además se observó que los aceros A36 recubiertos con CrN pueden ser una alternativa para reemplazar a los aceros inoxidables en ambientes ácidos.Los mecanismos de corrosión para los recubrimientos producidos son discutidos en esta investigación.This work was aimed at comparing the corrosion resistance of CrN and CrN/Cr coatings deposited through unbalanced magnetron sputtering (UBM, Cr industrial coatings and epoxy paints. UBM coatings were optimised and produced at room temperature, using 400 mA discharge current. Ar and N2 flow rates were set at 9 standard cubic centimetres per minute (SCCM and 3 SCCM, respectively. Deposition times were set to produce CrN monolayers and nanometric multilayers having 1 μm total thickness and 100 nm period. Coating icrostructure was determined through scanning electron microscopy as texture and crystalline phases were determined using

  7. Evaluation of thiosulfate as a substitute for hydrogen sulfide in sour corrosion fatigue studies

    Science.gov (United States)

    Kappes, Mariano Alberto

    This work evaluates the possibility of replacing hydrogen sulfide (H 2S) with thiosulfate anion (S2O32- ) in sour corrosion fatigue studies. H2S increases the corrosion fatigue crack growth rate (FCGR) and can be present in carbon steel risers and flowlines used in off-shore oil production. Corrosion tests with gaseous H2S require special facilities with safety features, because H2S is a toxic and flammable gas. The possibility of replacing H2S with S2O32-, a non-toxic anion, for studying stress corrosion cracking of stainless and carbon steels in H2S solutions was first proposed by Tsujikawa et al. ( Tsujikawa et al., Corrosion, 1993. 49(5): p. 409-419). In this dissertation, Tsujikawa work will be extended to sour corrosion fatigue of carbon steels. H2S testing is often conducted in deareated condition to avoid oxygen reaction with sulfide that yields sulfur and to mimic oil production conditions. Nitrogen deareation was also adopted in S2O3 2- testing, and gas exiting the cell was forced through a sodium hydroxide trap. Measurements of the sulfide content of this trap were used to estimate the partial pressure of H2S in nitrogen, and Henry's law was used to estimate the content of H2S in the solution in the cell. H2S was produced by a redox reaction of S2O 32-, which required electrons from carbon steel corrosion. This reaction is spontaneous at the open circuit potential of steel. Therefore, H2S concentration was expected to be maximum at the steel surface, and this concentration was estimated by a mass balance analysis. Carbon steel specimens exposed to S2O32- containing solutions developed a film on their surface, composed by iron sulfide and cementite. The film was not passivating and a good conductor of electrons. Hydrogen permeation experiments proved that this film controls the rate of hydrogen absorption of steels exposed to thiosulfate containing solutions. The absorption of hydrogen in S2O3 2- solutions was compared with the absorption of hydrogen in

  8. X-rays absorption study on medieval corrosion layers for the understanding of very long-term indoor atmospheric iron corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Monnier, J. [SIS2M UMR 3299 CEA-CNRS, Laboratoire Archeomateriaux et Prevision de l' Alteration (LAPA), Gif/Yvette cedex (France); UMR 7182 CNRS and UPEC, Universite Paris-Est, Institut de Chimie et des Materiaux Paris-Est (ICMPE), Thiais (France); Reguer, S.; Vantelon, D. [Synchrotron SOLEIL, Gif-sur-Yvette (France); Dillmann, P. [SIS2M UMR 3299 CEA-CNRS, Laboratoire Archeomateriaux et Prevision de l' Alteration (LAPA), Gif/Yvette cedex (France); IRAMAT UMR 5060 CNRS, Gif sur Yvette (France); Neff, D. [SIS2M UMR 3299 CEA-CNRS, Laboratoire Archeomateriaux et Prevision de l' Alteration (LAPA), Gif/Yvette cedex (France); Guillot, I. [UMR 7182 CNRS and UPEC, Universite Paris-Est, Institut de Chimie et des Materiaux Paris-Est (ICMPE), Thiais (France)

    2010-05-15

    The study and prediction of very long-term atmospheric corrosion behaviour of ferrous alloys is of great importance in different fields. First the conservation of metallic artefacts in museum and the corrosion diagnosis on ferrous reinforcement used in ancient monuments since medieval times needs reliable data to understand the mechanisms. Second, in the frame of the interim storage of nuclear waste in France, it is necessary to model the long-term corrosion of low alloy steel overcontainer. The nature of phases and elements constituting the corrosion layers can greatly influence the corrosion mechanisms. On the one hand, it is crucial to precisely determine the nature of microscopic phases that can be highly reactive. On the other hand, some elements as P and S could modify this reactivity. To clarify this point and complementary to other studies using Raman micro spectroscopy technique, X-rays Absorption Spectroscopy (XAS) under synchrotron radiation plays a crucial role. It allows one to precisely identify the reactive phases in the corrosion layers. Micro-XAS was required in order to refine the spatial variation, at micrometer scale, of the predominant Fe oxidation state and to characterise the corresponding corrosion products. Moreover, the role of minor elements on phase's stability and the chemical form of these elements in the rust layer, especially phosphorus and sulphur, was investigated. (orig.)

  9. Application of Moessbauer Spectroscopy to the Study of Corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Desmond C. [Old Dominion University, Department of Physics (United States)

    2004-03-15

    Corrosion research, and the need to fully understand the effects that environmental conditions have on the performance of structural steels, is one area in which Moessbauer spectroscopy has become a required analytical technique. This is in part due to the need to identify and quantify the nanophase iron oxides that form on and protect certain structural steels, and that are nearly transparent to most other spectroscopic techniques. A review is given of the most recent Moessbauer characterization of rusts that have formed on structural steels exposed to different environments. Moessbauer spectroscopy is playing an important role in a new corrosion program in the United States in which steel bridges, old and new, are being evaluated for corrosion problems that may reduce their serviceable lifetimes. Moessbauer spectroscopy has been used to characterize the corrosion products that form the protective patina on weathering steel, as well those that form in adverse environments in which the oxide coating is not adherent or protective to the steel. Moessbauer spectroscopy has also become an important analytical technique for investigating the corrosion products that have formed on archeological artifacts, and it is providing guidance to aid in the removal of the oxides necessary for their preservation.

  10. Study on applying technology of utilizing long-term materials for corrosion facilities

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Chul; Park, Young Kyu; Baek, Soo Gon; Lee, Jong Sub [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Park, Yong Soo [Yonsei University, Seoul (Korea, Republic of); Hwang, Won Suk [Inha University (Korea, Republic of); Song, Rhyo Seong [Hankuk Aviation, University (Korea, Republic of)

    1996-12-31

    Nowadays, as the pollution in seawater is escalating rapidly because of fast industrialization, corrosion rate and repairing frequency of seawater facilities in power plant are increasing. In addition, new construction is restricted with narrow limits due to the deterioration of social condition, asking for extension of facility life and repairing frequency. The objectives of this study are to select the appropriate new high corrosion resistance materials and apply them in the field, to make the corrosion data base in accordance with their usage conditions and to predict the remaining life and optimum repairing period by predicting the life of facilities. (author). 77 refs., 54 figs.

  11. Studies on Wear and Corrosion Resistances of Carbon Nitride Thin Films on Ti Alloy

    Institute of Scientific and Technical Information of China (English)

    LiJin-chai; GuoHuai-xi; LuXlan-feng; ZhangZhi-hong; YeMing-sheng

    2003-01-01

    CNx/SiCN composite films were prepared on titanium ( Ti ) alloy substrates by Radio Frequency Plasma Enhanced Chemical Vapor Deposition ( RF-PECVD ). As a buffer layer, SiCN ensured the adhesion of the CNx thin films on Ti substrates. X-ray diffraction (XRD) measurement revealed that the composite films possessed α-C3N4 structure.The microhardness of the films was 48 to 50 GPa. In or der totest the characteristics of wear and corrosion resistances, we prepared Ti alloy samples with and without CNx/SiCN composite films. Also for strengthening the effect of wear and corrosion, the wear tests were carried out under high load (12 MPa) and in 0. 9% NaCl solution. Results of the wear tests and the corrosive electrochemical measurements showed that the samples coated with CNx films had excellent charac-teristics of wear and corrosion resistances compared with Ti alloy substrate samples.

  12. Studies on Wear and Corrosion Resistances of Carbon Nitride Thin Films on Ti Alloy

    Institute of Scientific and Technical Information of China (English)

    Li Jin-chai; Guo Huai-xi; Lu Xian-feng; Zhang Zhi-hong; Ye Ming-sheng

    2003-01-01

    CNx/SiCN composite films were prepared on titanium ( Ti ) alloy substrates by Radio Frequency Plasma Enhanced Chemical Vapor Deposition ( RF-PECVD ). As a buffer layer, SiCN ensured the adhesion of the CNx thin films on Ti substrates. X-ray diffraction (XRD) measurement revealed that the composite films possessed α-C3N4 structure.The microhardness of the films was 48 to 50 GPa. In order to test the characteristics of wear and corrosion resistances, we prepared Ti alloy samples with and without CNx/SiCN composite films. Also for strengthening the effect of wear and corrosion, the wear tests were carried out under high load (12 MPa) and in 0. 9% NaCl solution. Results of the wear tests and the corrosive electrochemical measurements showed that the samples coated with CNx films had excellent characteristics of wear and corrosion resistances compared with Ti alloy substrate samples.

  13. Corrosion studies by use of the thermogravimetric analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Brinker, G.M.

    1995-11-01

    A series of tests have been performed by use of the thermogravimetric analyzer. Weight gain vs. time graphs have been generated by exposing one inch by two inch by sixty five hundredths of an inch low carbon (1020) steel specimens to a range of relative humidities (65%-90%) and temperatures (50-70{degrees}C). Data collected from these studies will give insight to both the kinetics of oxide formation and the material`s critical relative humidity. It has been observed that two separate rates and mechanisms for oxide formation exist. It is believed that dry oxidation is prevalent at low relative humidities, while aqueos electrochemical corrosion persists at high relative humidities. The relative humidity(s) and temperatures that oxidation formation transforms from one rate and mechanism to the other is of interest. The critical relative humidity is defined as the relative humidity at which oxide formation will become highly accelerated with respect to its normal growth rate. Hence, a better understanding of 1020 steel`s oxide formation kinetics and the alloy`s critical relative humidity will aid in waste package designs for use in conjunction with the proposed nuclear waste containment center at Yucca Mountain.

  14. Corrosion of archaeological iron artefacts compared to modern iron at the waterlogged site Nydam, Denmark

    DEFF Research Database (Denmark)

    Matthiesen, Henning; Hilbert, Lisbeth Rischel; Gregory, David

    2004-01-01

    loss, corrosion potential, electrochemical impedance spectroscopy and electrical resistivity. 3) Measurements of environmental parameter such as water level, redox potential, oxygen concentration, soil pH, and the concentration of a range of dissolved species in the pore water. This presentation shows...

  15. Hot Corrosion Studies in Coal Fired Boiler Environment

    Directory of Open Access Journals (Sweden)

    Kamal Subhash

    2014-07-01

    Full Text Available Hot corrosion behaviour of the bare and D-gun coated superfer 800H exposed to low temperature super-heater zone of the coal fired boiler of Guru Nanak Dev Thermal Power Plant, Bathinda, Punjab, India. The specimens were hanged in the platen super-heater of coal fired boiler where the gas temperature was around 900 °C ±10 °C. Hot corrosion experiments were performed for 10 cycles, each cycle consisting of 100 hours exposure followed by 1 hour cooling at ambient temperature. Weight change measurements were done at the end of each cycle. The weight change data used for predicting hot corrosion behaviour of the coated alloys after the total exposure of 1000 hours. The different phases and their distribution in the hot corroded specimens were analysed with the help of FE-SEM/EDS and X-ray mapping.

  16. Review: Results of studying atmospheric corrosion in Vietnam 1995–2005

    Directory of Open Access Journals (Sweden)

    Le Thi Hong Lien, Pham Thy San and Hoang Lam Hong

    2007-01-01

    Full Text Available Vietnam is situated in the wet tropical zone; thus, atmospheric conditions are characterized by high temperatures and a long time of wetness (TOW. In addition, the salt air coming in from the sea causes a high chloride concentration in coastal areas. Furthermore, Vietnam is a developing country, which means that air pollution is increasing with the development of industry. These factors result in significant damage to materials by atmospheric corrosion. In this report, the results of a recent study on the corrosion of carbon steel and zinc-galvanized steel at 6–8 testing sites in Vietnam over 10 recent years (1995–2005 are focused on as well as the effects of environmental factors on atmospheric corrosion. The results showed that the corrosion of carbon steel is dominated by TOW, whereas zinc-galvanized-steel corrosion strongly depends on the chloride ion concentration in the air. The corrosion losses of both carbon- and zinc-galvanized steel fit the power model well with high correlation coefficients. In addition, the characteristics of the Vietnamese climate are introduced in the form of distribution maps of temperature (T, relative humidity (RH, total rainfall and TOW. A relationship between TOW, T and RH was found that enabled the calculation of TOW from T and RH data, which are available at meteorological stations. Finally, atmospheric corrosivity is determined on the basis of data on TOW, Cl− and SO2 concentrations, and the carbon steel corrosion rate. It is shown that in Vietnam, TOW is so long that the corrosion rate of carbon steel is in the C3 category; nevertheless, Cl− and SO2 concentrations in the atmosphere are not high.

  17. ELECTROCHEMICAL STUDY ON THE LOCALIZED CORROSION OF TWO DIFFERENT TEMPER LY12 ALLOYS

    Institute of Scientific and Technical Information of China (English)

    F.H. Cao; L. Guo; L.J. Zhang; Z. Zhang; J.Q. Zhang

    2005-01-01

    The corrosion behavior of two different aged LY12 alloys in EXCO (234g/L NaCl, 50g/L KNO3,0. 1M HNO3) and MIL-H-600 (35g/L NaCl, 5g/L (NH4)2SO4) solutions were studied using electrochemical impedance spectroscopy (EIS) in conjunction with SEM technique respectively, and the pH variation of the above accelerated corrosion solution during materials corroding was also measured to characterize the corrosion processes. At the beginning of corrosion, EIS plots exhibited two capacitive arcs in the high frequency range (Ca) and mediate frequency range (Cy) originating from the original corroded surface and the newly formed interface respectively,and a low frequency inductive loop due to the relaxation phenomenon of reaction intermediates.In the EXCO.solution, the EIS results showed that once the exfoliation corrosion occurred, the inductive loop disappeared. The results also showed that the exfoliation corrosion susceptibility of state T6 is much higher than that of state T3, but the intergranular corrosion susceptibility has a reverse order. Based on the relationship of EIS results with SEM and metalloscopy morphologies of the corroding substrates and physic-chemical meaning of EIS parameters, an index (Cg/ Ca) has been proposed to characterize the extent of the localized corrosion, which variation tallies with the real corrosion extent correctly. Meanwhile, good agreement was found between the experimental results and the electrochemical model proposed and, good coherence between the electrochemical features and the distribution type of constituent particles of corroding material was observed.

  18. A theoretical study of carbohydrates as corrosion inhibitors of iron

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, Salim M.; Ali, Nozha M. [Libyan Academy for Graduate Studies, Tripoli (Libyan Arab Jamahiriya). Chemistry Dept.; Ali-Shattle, Elbashir E. [Tripoli Univ. (Libyan Arab Jamahiriya). Chemistry Dept.

    2013-08-15

    The inhibitive effect of fructose, glucose, lactose, maltose, and sucrose against the iron corrosion is investigated using density functional theory at the B3LYP/6-31 G level (d) to search the relation between the molecular structure and corrosion inhibition. The electronic properties such as the energy of the highest occupied molecular orbital (HOMO), the energy of lowest unoccupied orbital (LUMO), the energy gap (LUMO-HOMO), quantum chemical parameters such as hardness, softness, the fraction of the electron transferred, and the electrophilicity index are reported. The inhibition efficiency of the investigated carbohydrates follows the trend: maltose < sucrose < lactose < fructose < glucose. (orig.)

  19. Sample environment for in situ synchrotron corrosion studies of materials in extreme environments

    Science.gov (United States)

    Elbakhshwan, Mohamed S.; Gill, Simerjeet K.; Motta, Arthur T.; Weidner, Randy; Anderson, Thomas; Ecker, Lynne E.

    2016-10-01

    A new in situ sample environment has been designed and developed to study the interfacial interactions of nuclear cladding alloys with high temperature steam. The sample environment is particularly optimized for synchrotron X-ray diffraction studies for in situ structural analysis. The sample environment is highly corrosion resistant and can be readily adapted for steam environments. The in situ sample environment design complies with G2 ASTM standards for studying corrosion in zirconium and its alloys and offers remote temperature and pressure monitoring during the in situ data collection. The use of the in situ sample environment is exemplified by monitoring the oxidation of metallic zirconium during exposure to steam at 350 °C. The in situ sample environment provides a powerful tool for fundamental understanding of corrosion mechanisms by elucidating the substoichiometric oxide phases formed during the early stages of corrosion, which can provide a better understanding of the oxidation process.

  20. Microbially influenced corrosion: studies on enterobacteria isolated from seawater environment and influence of toxic metals on bacterial biofilm and bio-corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Bermond-Tilly, D.; Pineau, S.; Dupont-Morral, I. [Corrodys, 50 - Equeurdreville (France); Janvier, M.; Grimont, P.A.D. [Institut Pasteur, Unite BBPE, 75 - Paris (France)

    2004-07-01

    of microbial clusters and the increase production of the EPS by bacteria (Fang et al., 2002). This study was conducted to test the corrosive activity of Citrobacter freundii, Proteus mirabilis and Klebsiella planticola on carbon steel coupons and the influence of a toxic metal Cr(III) found in polluted marine environment) on these bacteria and the EPS production of the biofilm formed on carbon steel by appropriate in vitro experiments. (authors)

  1. Studies of the Low Temperature Hot Corrosion of Uncoated Superalloys.

    Science.gov (United States)

    1981-09-01

    Corrosion of Uncoated Superal loys * EPNIQoao. qEPORT NUMUER 7. AUTHOR,.I .CONTRACT OR11 GRANT IUR. Garry 0. flewberry 9. PERPOR0111MING ORGANIZATION ...Master’s Thesis, Naval Postgraduate School, M1onterey, 7, June 1981. 13. Exell , J. R., The Substrate Effect of Active Element Hafnium in Aluminide

  2. Corrosion behavior of titanium wires: An in vitro study

    Directory of Open Access Journals (Sweden)

    Thakur Prasad Chaturvedi

    2012-01-01

    Results: The results showed degradation of titanium wires by electrochemical attack when they were placed in the hostile electrolytic environments provided in the experiments. Surface analysis of titanium wires showed pitting and localized attacks on the surface. Pitting corrosion was found in the titanium wires.

  3. Comparative Corrosion Inhibition Effect of Imidazole Compounds and of Trichodesma indicum (Linn R. Br. on C38 Steel in 1 M HCl Medium

    Directory of Open Access Journals (Sweden)

    S. Alarmal Mangai

    2013-01-01

    Full Text Available Corrosion inhibition effect of alkaloid extract part of the plant Trichodesma indicum (Linn R. Br. of Boraginaceae family was studied and compared with that of imidazole compounds (imidazole, benzimidazole on C38 steel in 1 M HCl solution by weight loss method at various temperatures. The study showed that the alkaloid part of the plant extract acts as a better inhibitor in comparison to the selected organic inhibitors. The maximum inhibition efficiency of the extract of Trichodesma indicum R. Br. was found to be 94.5% at a concentration of 75 mg/L at 30°C.

  4. Corrosivity of paper mill effluent and corrosion performance of stainless steel.

    Science.gov (United States)

    Ram, Chhotu; Sharma, Chhaya; Singh, A K

    2015-01-01

    Present study relates to the corrosivity of paper mill effluent and corrosion performance of stainless steel (SS) as a construction material for the effluent treatment plant (ETP). Accordingly, immersion test and electrochemical polarization tests were performed on SS 304 L, 316 L and duplex 2205 in paper mill effluent and synthetic effluent. This paper presents electrochemical polarization measurements, performed for the first time to the best of the authors' information, to see the influence of chlorophenols on the corrosivity of effluents. The corrosivity of the effluent was observed to increase with the decrease in pH and increase in Cl- content while the addition of SO4- tends to inhibit corrosion. Mill effluent was found to be more corrosive as compared to synthetic effluent and has been attributed to the presence of various chlorophenols. Corrosion performance of SS was observed to govern by the presence of Cr, Mo and N contents.

  5. A rapid cyclic voltammetric method for studying cement factors affecting the corrosion of reinforced concrete

    Energy Technology Data Exchange (ETDEWEB)

    Foulkes, F.R.; McGrath, P. (Univ. of Toronto, Ontario (Canada))

    1999-06-01

    A rapid cyclic voltammetric method for studying the influence of cement factors on the corrosion of embedded iron and steel in hardened cement paste is described. The technique employs a cement electrode'' consisting of an iron or steel wire embedded in a miniature cylinder of hardened cement paste. The rapid cyclic voltammetric method is fast, reproducible, and provides information on the corrosiveness of the pore solution environment surrounding the embedded metal. The usefulness of the method is demonstrated by showing how it can be used to evaluate the threshold chloride content of hardened ordinary portland cement paste at which corrosion begins and by using it to evaluate the relative efficacy of several admixed corrosion inhibitors.

  6. Experimental and quantum chemical studies on corrosion inhibition performance of fluconazole in hydrochloric acid solution

    Indian Academy of Sciences (India)

    P Malekmohammadi Nouri; M M Attar

    2015-04-01

    The corrosion inhibition effect of fluconazole (FLU) was investigated on steel in 1 M hydrochloric acid solution. Weight loss measurements and atomic force microscope analysis were utilized to investigate the corrosion inhibition properties and film formation behaviour of FLU. Quantum chemical approach was also used to calculate some electronic properties of the molecule in neutral and protonated form in order to find any correlation between the inhibition effect and molecular structure of FLU molecule. The results showed that FLU can act as a good corrosion inhibitor for steel in hydrochloric acid solution at different temperatures and it can inhibit steel corrosion up to 95%. The adsorption followed the Langmuir isotherm and the thermodynamic parameters were also determined and discussed. Quantum chemical studies showed that in adsorption process of FLU molecules, nitrogen and oxygen atoms and benzene ring act as active centres.

  7. CEMS study of corrosion products formed by NaCl aqueous solution

    Science.gov (United States)

    Nakanishi, A.

    2012-03-01

    Conversion electron Mössbauer spectroscopy was used to study corrosion products by NaCl aqueous solution. A drop of the solution is put on an iron foil and the foil is left at RT. During the evaporation of the solution, corrosion products are formed. Conversion electron Mössbauer spectra were taken at temperatures between 15 K and room temperature (RT). In the Mössbauer spectra a ferric doublet is observed at RT, but sextets are found at 15 K. These results show that the corrosion product mainly consists of γ - FeOOH and a small amount of β - FeOOH is noticed. As NaCl concentration increases, the corrosion layer becomes thick and β- FeOOH / γ - FeOOH ratio increases slightly. Consequently, it has been concluded that the produced amount of β- FeOOH increases more rapidly than that of γ - FeOOH with increasing NaCl concentration.

  8. Study of a Triazole Derivative as Corrosion Inhibitor for Mild Steel in Phosphoric Acid Solution

    Directory of Open Access Journals (Sweden)

    Lin Wang

    2012-01-01

    Full Text Available The corrosion inhibition by a triazole derivative (PAMT on mild steel in phosphoric acid (H3PO4 solution has been investigated by weight loss and polarization methods. The experimental results reveal that the compound has a significant inhibiting effect on the corrosion of steel in H3PO4 solution. It also shows good corrosion inhibition at higher concentration of H3PO4. Potentiodynamic polarization studies have shown that the compound acts as a mixed-type inhibitor retarding the anodic and cathodic corrosion reactions with predominant effect on the cathodic reaction. The values of inhibition efficiency obtained from weight loss and polarization measurements are in good agreement. The adsorption of this compound is found to obey the Langmuir adsorption isotherm. Some kinetic and thermodynamic parameters such as apparent activation energy, frequency factor, and adsorption free energy have been calculated and discussed.

  9. Studies on corrosion protection of laser hybrid welded AISI 316 by laser remelting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Ambat, Rajan; Rasmussen, A.J.

    2005-01-01

    Unlike in autogenous laser welding, hybrid laser welding of stainless steel could introduce grain boundary carbides due to low cooling rates. Formation of grain boundary carbides leads to reduced corrosion properties. Studies have initially been carried out on hybrid laser welding and subsequent...... laser surface melting on microstructure and corrosion behaviour of AISI 316L welds. Welding and laser treatment parameters were varied. General corrosion behaviour of the weld and laser treated surface was characterised using a gel visualization test. The local electrochemistry of the weld and laser...... treated surface was investigated using a novel micro electrochemical technique with a tip resolution of ~1 mm. Results show that hybrid laser welding of 316L has increased corrosion susceptibility probably as a result of grain boundary carbide formation. However a suitable post laser treatment could...

  10. Test study of corrosion performances and wear characteristics of composite guide in vertical shaft

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, X.; Guo, J.; Xu, W. [Jiaozuo Institute of Technology, Jiaozuo (China)

    2000-10-01

    This paper describes the research of a new composite guide in the light of serious corrosion problem of vertical shaft equipment. Through the experimental study on the corrosion characteristics of the composite guide, it is pointed out that the corrosion resistance of the composite guide which is made of steel and glass fibre reinforced plastic (GFRP) can meet the needs of mine shaft environment. The minimum thickness of the GFRP material of the guide obtained from wear resistance test is put forward. It is found that the corrosion and wear resistance of the GFRP which protects the steel guide is over 30 years. Therefore, the replacement of shaft equipment will be less often, thereby conserving on capital investment. 5 refs., 5 figs., 3 tabs.

  11. Kinetic Study of the Effect of Selected Surfactants on Corrosion of Copper

    Directory of Open Access Journals (Sweden)

    Howaida M. El-Kashlan

    2008-01-01

    Full Text Available The rates of copper corrosion were determined by measuring the limiting current of anodic dissolution of copper in phosphoric acid in presence and in absence of cetyl trimethyl ammonium bromide (CTAB and cetyl pyridinium bromide (CPYB. The rate of corrosion is found to decrease by increasing the concentration of the surfactant. The percentage of inhibition ranged from 1.85 to 33.97% depending on the type of surfactant and its concentration. Increasing the copper electrode height, and concentration of H3PO4 decreases the rate of copper corrosion. The investigated adsorption isotherms indicate that the two surfactants fit Langmuir and Flory Huggins isotherm. The thermodynamic parameters show that corrosion is a diffusion controlled process. The dimensional analysis method was used to obtain the overall mass transfer correlations under the study conditions.

  12. Study on an Eco-Friendly Corrosion and Scale Inhibitor in Simulated cooling water

    Directory of Open Access Journals (Sweden)

    Defang Zeng1

    2013-01-01

    Full Text Available In this study, a composite eco-friendly phosphate-free corrosion and scale inhibitor used in simulated cooling water has been developed by sodium polyacrylate, zinc sulfate, sodium tungstate, sodium gluconate and triethanolamine . The corrosion and scale inhibition rate were respectively evaluated by weight loss experiment , the static scale inhibition test and electrochemical test. The results indicated that the corrosion and scale inhibitor was consisted of polyacrylate 14ppm,zinc sulfate 3ppm,sodium tungstate 7ppm,sodium gluconate 2ppm and triethanolamine12ppm.The corrosion inhibition rate could reached 92.79%, and anti-scaling inhibition rate could reached 96.01%. The formula was efficient , phosphate-free and environmental, it would be widely used

  13. Studies on corrosion protection of laser hybrid welded AISI 316 by laser remelting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Ambat, Rajan; Rasmussen, A.J.

    2005-01-01

    Unlike in autogenous laser welding, hybrid laser welding of stainless steel could introduce grain boundary carbides due to low cooling rates. Formation of grain boundary carbides leads to reduced corrosion properties. Studies have initially been carried out on hybrid laser welding and subsequent...... laser surface melting on microstructure and corrosion behaviour of AISI 316L welds. Welding and laser treatment parameters were varied. General corrosion behaviour of the weld and laser treated surface was characterised using a gel visualization test. The local electrochemistry of the weld and laser...... treated surface was investigated using a novel micro electrochemical technique with a tip resolution of ~1 mm. Results show that hybrid laser welding of 316L has increased corrosion susceptibility probably as a result of grain boundary carbide formation. However a suitable post laser treatment could...

  14. Systematic Study of Nanocrystalline Plasma Electrolytic Nitrocarburising of 316L Austenitic Stainless Steel for Corrosion Protection

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A number of studies have been reported on the use of nanocrystalline plasma electrolytic nitrocarburising technology for surface hardening of stainless steels for higher corrosion resistance resulted from this technique. However, very few studies have focused on the optimization of the nanocrystalline plasma electrolytic nitrocarburising process parameters. In this study, a design of experiment (DOE) technique, the Taguchi method, has been used to optimize the nanocrystalline plasma electrolytic nitrocarburising not only for surface hardening but also for the corrosion protection of 316L austenitic stainless steel by controlling the coating process's factors. The experimental design consisted of four factors (Urea concentration, electrical conductivity of electrolyte, voltage and duration of process), each containing three levels. Potentiodynamic polarization measurements were carried out to determine the corrosion resistance of the coated samples. The results were analyzed with related software. An analysis of the mean of signal-to-noise (S/N) ratio indicated that the corrosion resistance of nanocrystalline plasma electrolytic nitrocarburised 316L stainless steel was influenced significantly by the levels in the Taguchi orthogonal array. The optimized coating parameters for corrosion resistance are 1150 g/L for urea concentration, 360 mS/cm for electrical conductivity of electrolyte, 260 V for applied voltage, 6 min for treatment time. The percentage of contribution for each factor was determined by the analysis of variance (ANOVA). The results showed that the applied voltage is the most significant factor affecting the corrosion resistance of the coatings.

  15. Corrosion of RoHS-Compliant Surface Finishes in Corrosive Mixed Flowing Gas Environments

    Science.gov (United States)

    Hannigan, K.; Reid, M.; Collins, M. N.; Dalton, E.; Xu, C.; Wright, B.; Demirkan, K.; Opila, R. L.; Reents, W. D.; Franey, J. P.; Fleming, D. A.; Punch, J.

    2012-03-01

    Recently, the corrosion resistance of printed wiring board (PWB) finishes has generated considerable interest due to field failures observed in various parts of the world. This study investigates the corrosion issues associated with the different lead-free PWB surface finishes. Corrosion products on various PWB surface finishes generated in mixed flowing gas (MFG) environments were studied, and analysis techniques such as scanning electron microscopy, energy-dispersive x-ray, x-ray diffraction, focused ion beam, and scanning Auger microscopy were used to quantify the corrosion layer thickness and determine the composition of corrosion products. The corrosion on organic solderability preservative samples shows similar corrosion products to bare copper and is mainly due to direct attack of copper traces by corrosive gases. The corrosion on electroless nickel immersion gold occurs primarily through the porosity in the film and is accelerated by the galvanic potential between gold and copper; similar results were observed on immersion silver. Immersion tin shows excellent corrosion resistance due to its inherent corrosion resistance in the MFG environment as well as the opposite galvanic potential between tin and copper compared with gold or silver and copper.

  16. EIS study on corrosion and scale processes and their inhibition in cooling system media

    Energy Technology Data Exchange (ETDEWEB)

    Marin-Cruz, J. [Universidad Autonoma Metropolitana, Departamento de Quimica, Apdo. Postal 55-534, 09340 Mexico, DF (Mexico) and Instituto Mexicano del Petroleo, Coordinacion de Ingenieria Molecular, Competencia de Quimica Aplicada, Eje Central Lazaro Cardenas No. 152, CP 07730, DF (Mexico)]. E-mail: jmarin@imp.mx; Cabrera-Sierra, R. [Universidad Autonoma Metropolitana, Departamento de Quimica, Apdo. Postal 55-534, 09340 Mexico, DF (Mexico); Escuela Superior de Ingenieria Quimica e Industrias Extractivas (ESIQIE-IPN), Departamento de Metalurgia, UPALM Zacatenco AP 75-874, CP 07338, DF (Mexico); Pech-Canul, M.A. [Departamento de Fisica Aplicada, Centro de Investigacion y de Estudios, Avanzados del IPN, AP 73 Cordemex, CP 97310, Merida, Yucatan (Mexico); Gonzalez, I. [Universidad Autonoma Metropolitana, Departamento de Quimica, Apdo. Postal 55-534, 09340 Mexico, DF (Mexico)]. E-mail: igm@xanum.uam.mx

    2006-01-20

    A study of the carbon steel/cooling water interface was carried out using electrochemical impedance spectroscopy (EIS). EIS spectra reveal that a layer of corrosion and scale products forms naturally and evolves with the immersion time modifying the carbon steel/cooling water interface and giving rise to corrosion and scale processes. In addition, the nature of the layer formed on the metal was found to depend on the inhibitor used. It was established that the corrosion inhibitor (hydroxyphosphonoacetic acid (HPA)) chelates with Ca(II) ion generating a layer with resistive properties that provides good protection against corrosion. In contrast, the scale inhibitor (1-hydroxy-ethane-1,1-diphosphonic acid (HEDP)) is incorporated into the calcium carbonate crystals at the surface, modifying the structure and diminishing scale formation in the surface; this additive additionally inhibited corrosion. These observations were supported by scanning electronic microscopy (SEM) and corroborate previous studies performed by other techniques on HPA and HEDP. Finally, a synergistic effect was observed between these inhibitors that provides good protection to steel against corrosion and scaling in cooling media.

  17. In vitro studying corrosion behavior of porous titanium coating in dynamic electrolyte.

    Science.gov (United States)

    Chen, Xuedan; Fu, Qingshan; Jin, Yongzhong; Li, Mingtian; Yang, Ruisong; Cui, Xuejun; Gong, Min

    2017-01-01

    Porous titanium (PT) is considered as a promising biomaterials for orthopedic implants. Besides biocompatibility and mechanical properties, corrosion resistance in physiological environment is the other important factor affecting the long stability of an implant. In order to investigate the corrosion behavior of porous titanium implants in a dynamic physiological environment, a dynamic circle system was designed in this study. Then a titanium-based implant with PT coating was fabricated by plasma spraying. The corrosion resistance of PT samples in flowing 0.9% NaCl solution was evaluated by electrochemical measurements. Commercial pure solid titanium (ST) disc was used as a control. The studies of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) show that the pores in the PT play a negetive part in corrosion resistance and the flowing electrolyte can increase the corrosive rate of all titanium samples. The results suggest that pore design of titanium implants should pay attention to the effect of dynamic process of a physiological environment on the corrosion behavior of implants. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Selected durability studies of geopolymer concrete with respect to carbonation, elevated temperature, and microbial induced corrosion

    Science.gov (United States)

    Badar, Mohammad Sufian

    This thesis reports a comprehensive study related to the experimental evaluation of carbonation in reinforced geopolymer concrete, the evaluation of geopolymer concretes at elevated temperature, and the resistance of geopolymer concrete to microbial induced corrosion (MIC). Carbonation: Reinforced concretes, made of geopolymer, prepared from two class F fly ashes and one class C fly ash, were subjected to accelerated carbonation treatment for a period of 450 days. Electrochemical, microstructure and pore structure examinations were performed to evaluate the effect of corrosion caused due to carbonation. GPC specimens prepared from class F fly ash exhibited lower corrosion rates by a factor of 21, and higher pH values (pH>12) when compared with concrete specimens prepared from class C Fly ash (GPCMN). Microstructure and pore characterization of GPC prepared using class F fly ash revealed lower porosity by a factor of 2.5 as compared with thier counterparts made using GPC-MN. The superior performace of GPC prepared with the class F fly ash could be attributed to the dense pore structure and formation of the protective layer of calcium and sodium alumino silicate hydrates (C/N-A-S-H) geopolymeric gels around the steel reinforcement. Elevated Temperature: Geopolymers are an emerging class of cementitious binders which possess a potential for high temperature resistance that could possibly be utilized in applications such as nozzles, aspirators and refractory linings. This study reports on the results of an investigation into the performance of a fly ash based geopolymer binder in high temperature environments. Geopolymer concrete (GPC) was prepared using eleven types of fly ashes obtained from four countries. High content alumina and silica sand was used in the mix for preparing GPC. GPC was subjected to thermal shock tests following ASTM C 1100-88. The GPC samples prepared with tabular alumina were kept at 1093° C and immediately quenched in water. GPC specimens

  19. Operations dashboard: comparative study

    Science.gov (United States)

    Ramly, Noor Nashriq; Ismail, Ahmad Zuhairi; Aziz, Mohd Haris; Ahmad, Nurul Haszeli

    2011-10-01

    In this present days and age, there are increasing needs for companies to monitor application and infrastructure health. Apart from having proactive measures to secure their application and infrastructure, many see monitoring dashboards as crucial investment in disaster preparedness. As companies struggle to find the best solution to cater for their needs and interest for monitoring their application and infrastructure's health, this paper summarizes the studies made on several known off-the-shelf operations dashboard and in-house developed dashboard. A few criteria of good dashboard are collected from previous studies carried out by several researchers and rank them according to importance and business needs. The finalized criteria that will be discussed in later sections are data visualization, performance indicator, dashboard personalization, audit capability and alert/ notification. Comparative studies between several popular dashboards were then carried out to determine whether they met these criteria that we derived from the first exercise. The findings hopefully can be used to educate and provide an overview of selecting the best IT application and infrastructure operations dashboard that suit business needs, thus become the main contribution of this paper.

  20. The Study of Corrosion and Wear Resistance of Copper Composite Coatings with Inclusions of Carbon Nanomaterials in the Copper Metal Matrix

    Directory of Open Access Journals (Sweden)

    Viktorija MEDELIENĖ

    2011-07-01

    Full Text Available This paper deals with the peculiarities of the behaviour of copper nanocomposite coatings with CNMs inclusions under the free corrosion conditions in the acidic medium. The parameters of corrosion current density (jcorr, anodic dissolution current density (ia and polarization resistance (Rp have been determined. In the acidic medium a stronger oxidation of nanostructured copper nanocomposites occurred. With longer immersion periods more corrosion products are formed, resulting in a increase in the polarization resistance (Rp of corrosion. Corrosion products cover the whole surface of the coatings and the corrosion rate (jcorr tends towards a steady value of 1.7×10-3 ¸ 2.1×10-3 A·cm-2 for all copper coatings studied: 1.7×10-3 A·cm-2 for both Cu and Cu-CNM1, 1.9×10-3 A·cm-2 - for Cu-CNM2 and 2.1×10-3 A·cm-2 - for Cu-CNM3 composite coatings. It has been established that nanocomposites possess a higher wear resistance as compared to that of pure copper. The damage of metal characterized as a depth scar (đ is lower. The roughness of the composites studied was found to be the essential factor affecting their wear resistance. Therefore, the wear resistance of nanocomposites is impaired when they are deposited on a hard steel substrate.http://dx.doi.org/10.5755/j01.ms.17.2.481

  1. The Study of Corrosion and Wear Resistance of Copper Composite Coatings with Inclusions of Carbon Nanomaterials in the Copper Metal Matrix

    Directory of Open Access Journals (Sweden)

    Viktorija MEDELIENĖ

    2011-07-01

    Full Text Available This paper deals with the peculiarities of the behaviour of copper nanocomposite coatings with CNMs inclusions under the free corrosion conditions in the acidic medium. The parameters of corrosion current density (jcorr, anodic dissolution current density (ia and polarization resistance (Rp have been determined. In the acidic medium a stronger oxidation of nanostructured copper nanocomposites occurred. With longer immersion periods more corrosion products are formed, resulting in a increase in the polarization resistance (Rp of corrosion. Corrosion products cover the whole surface of the coatings and the corrosion rate (jcorr tends towards a steady value of 1.7×10-3 ¸ 2.1×10-3 A·cm-2 for all copper coatings studied: 1.7×10-3 A·cm-2 for both Cu and Cu-CNM1, 1.9×10-3 A·cm-2 - for Cu-CNM2 and 2.1×10-3 A·cm-2 - for Cu-CNM3 composite coatings. It has been established that nanocomposites possess a higher wear resistance as compared to that of pure copper. The damage of metal characterized as a depth scar (đ is lower. The roughness of the composites studied was found to be the essential factor affecting their wear resistance. Therefore, the wear resistance of nanocomposites is impaired when they are deposited on a hard steel substrate.http://dx.doi.org/10.5755/j01.ms.17.2.481

  2. Comparative waste forms study

    Energy Technology Data Exchange (ETDEWEB)

    Wald, J.W.; Lokken, R.O.; Shade, J.W.; Rusin, J.M.

    1980-12-01

    A number of alternative process and waste form options exist for the immobilization of nuclear wastes. Although data exists on the characterization of these alternative waste forms, a straightforward comparison of product properties is difficult, due to the lack of standardized testing procedures. The characterization study described in this report involved the application of the same volatility, mechanical strength and leach tests to ten alternative waste forms, to assess product durability. Bulk property, phase analysis and microstructural examination of the simulated products, whose waste loading varied from 5% to 100% was also conducted. The specific waste forms investigated were as follows: Cold Pressed and Sintered PW-9 Calcine; Hot Pressed PW-9 Calcine; Hot Isostatic Pressed PW-9 Calcine; Cold Pressed and Sintered SPC-5B Supercalcine; Hot Isostatic pressed SPC-5B Supercalcine; Sintered PW-9 and 50% Glass Frit; Glass 76-68; Celsian Glass Ceramic; Type II Portland Cement and 10% PW-9 Calcine; and Type II Portland Cement and 10% SPC-5B Supercalcine. Bulk property data were used to calculate and compare the relative quantities of waste form volume produced at a spent fuel processing rate of 5 metric ton uranium/day. This quantity ranged from 3173 L/day (5280 Kg/day) for 10% SPC-5B supercalcine in cement to 83 L/day (294 Kg/day) for 100% calcine. Mechanical strength, volatility, and leach resistance tests provide data related to waste form durability. Glass, glass-ceramic and supercalcine ranked high in waste form durability where as the 100% PW-9 calcine ranked low. All other materials ranked between these two groupings.

  3. A Study on Accelerated Corrosion Test by Combined Deteriorating Action of Salt Damage and Freeze-Thaw

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang-Soon; So, Byung-Tak [Sangmyung University, Cheonan (Korea, Republic of)

    2016-01-15

    In this study, the accelerated corrosion test by combined deteriorating action of salt damage and freeze-thaw was investigated. freeze-thaw cycle is one method for corrosion testing; corrosion initiation time was measured in four types of concrete samples, i.e., two samples mixed with fly ash (FA) and blast furnace slag (BS), and the other two samples having two water/cement ratio (W/C = 0.6, 0.35) without admixture (OPC60 and OPC35). The corrosion of rebar embedded in concrete occurred most quickly at the 30th freeze-thaw cycle. Moreover, a corrosion monitoring method with a half-cell potential measurement and relative dynamic elastic modulus derived from resonant frequency measures was conducted simultaneously. The results indicated that the corrosion of rebar occurred when the relative dynamic elastic modulus was less than 60%. Therefore, dynamic elastic modulus can be used to detect corrosion of steel bar. The results of the accelerated corrosion test exhibited significant difference according to corrosion periods combined with each test condition. Consequently, the OPC60 showed the lowest corrosion resistance among the samples.

  4. Enhancement of corrosion resistance of polypyrrole using metal oxide nanoparticles: Potentiodynamic and electrochemical impedance spectroscopy study.

    Science.gov (United States)

    Hosseini, Marzieh; Fotouhi, Lida; Ehsani, Ali; Naseri, Maryam

    2017-11-01

    We introduce a simple and facile strategy for dispersing of nanoparticles within a p-type conducting polymer matrix by in situ electropolymerization using oxalic acid as the supporting electrolyte. Coatings prepared from polypyrrole-nano-metal oxide particles synthesized by in situ polymerization were found to exhibit excellent corrosion resistance much superior to polypyrrole (Ppy) in aggressive environments. The anti-corrosion behavior of polypyrrole films in different states and the presence of TiO2, Mn2O3 and ZnO nanoparticles synthesized by electropolymerization on Al electrodes have been investigated in corrosive solutions using potentiodynamic polarization and electrochemical impedance spectroscopy. The electrochemical response of the coated electrodes in polymer and nanocomposite state was compared with bare electrodes. The use of TiO2 nanoparticles has proved to be a great improvement in the performances of polypyrrole films for corrosion protection of Al samples. The polypyrrole synthesized in the presence of TiO2 nanoparticles coated electrodes offered a noticeable enhancement of protection against corrosion processes. The exceptional improvement of performance of these coatings has been associated with the increase in barrier to diffusion, prevention of charge transport by the nanosize TiO2, redox properties of polypyrrole as well as very large surface area available for the liberation of dopant due to nano-size additive. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Friction surfacing for enhanced surface protection of marine engineering components: erosion-corrosion study

    Science.gov (United States)

    Rajakumar, S.; Balasubramanian, V.; Balakrishnan, M.

    2016-08-01

    Good mechanical properties combined with outstanding corrosion-resistance properties of cast nickel-aluminum bronze (NAB) alloy lead to be a specific material for many marine applications, including ship propellers. However, the erosion-corrosion resistance of cast-NAB alloy is not as good as wrought NAB alloy. Hence, in this investigation, an attempt has been made to improve the erosion-corrosion resistance of cast NAB alloy by depositing wrought (extruded) NAB alloy applying the friction surfacing (FS) technique. Erosion-corrosion tests were carried out in slurries composed of sand particles of 3.5% NaCl solution. Silica sand having a nominal size range of 250-355 μm is used as an erodent. Specimens were tested at 30° and 90° impingement angles. It is observed that the erosion and erosion-corrosion resistance of friction surfaced NAB alloy exhibited an improvement as compared to cast NAB alloy. Scanning electron microscope (SEM) analysis showed that the erosion tracks developed on the cast NAB alloy were wider and deeper than those formed on the friction surfaced extruded NAB alloy.

  6. Evaluation of oxygen corrosion in waterflood and disposal water systems

    Energy Technology Data Exchange (ETDEWEB)

    Conger, H.C.

    1967-01-01

    The case histories presented illustrate how specially polished pipe nipples have been used and examined in the field to evaluate the seriousness of an oxygen corrosion problem. The case histories also illustrate how these test pipe nipples have been used to evaluate actual, not relative, effectiveness of a chemical treatment program to control oxygen corrosion. Data are presented and discussed showing the relationship between corrosion rates of test pipe nipples and actual in-service equipment. The case histories show how corrosion rates based on pipe test nipple data were used to project equipment life under no chemical treatment vs. chemical treatment. A comparative study of corrosion rates between the use of pipe nipples and coupons as a means of measuring oxygen corrosion is discussed. A further comparative study is made between coupon corrosion rates based on weight loss and pit depth penetration.

  7. A STUDY ON THE CORROSION RESISTANCE OF BRONZES COVERED WITH ARTIFICIAL PATINA

    Directory of Open Access Journals (Sweden)

    Julieta Daniela SABĂU (CHELARU

    2011-06-01

    Full Text Available In recent years, due to increased air pollution, bronze objects exposed in urban areas suffer continuous degradation. Therefore, it is important to find efficient methods to protect them against corrosion. The present work aims to investigate the corrosion resistance of various artificial patina currently used in bronze sculpture. Once formed, the patina is relative stable and acts as a protective coating of the bronze object under many exposure conditions. The protective effect of different artificial patinas was comparatively investigated by electrochemical and non-electrochemical methods.

  8. Natural analogues of nuclear waste glass corrosion.

    Energy Technology Data Exchange (ETDEWEB)

    Abrajano, T.A. Jr.; Ebert, W.L.; Luo, J.S.

    1999-01-06

    This report reviews and summarizes studies performed to characterize the products and processes involved in the corrosion of natural glasses. Studies are also reviewed and evaluated on how well the corrosion of natural glasses in natural environments serves as an analogue for the corrosion of high-level radioactive waste glasses in an engineered geologic disposal system. A wide range of natural and experimental corrosion studies has been performed on three major groups of natural glasses: tektite, obsidian, and basalt. Studies of the corrosion of natural glass attempt to characterize both the nature of alteration products and the reaction kinetics. Information available on natural glass was then compared to corresponding information on the corrosion of nuclear waste glasses, specifically to resolve two key questions: (1) whether one or more natural glasses behave similarly to nuclear waste glasses in laboratory tests, and (2) how these similarities can be used to support projections of the long-term corrosion of nuclear waste glasses. The corrosion behavior of basaltic glasses was most similar to that of nuclear waste glasses, but the corrosion of tektite and obsidian glasses involves certain processes that also occur during the corrosion of nuclear waste glasses. The reactions and processes that control basalt glass dissolution are similar to those that are important in nuclear waste glass dissolution. The key reaction of the overall corrosion mechanism is network hydrolysis, which eventually breaks down the glass network structure that remains after the initial ion-exchange and diffusion processes. This review also highlights some unresolved issues related to the application of an analogue approach to predicting long-term behavior of nuclear waste glass corrosion, such as discrepancies between experimental and field-based estimates of kinetic parameters for basaltic glasses.

  9. Study of sulphate-reducing bacteria corrosion in the weld joint for API X-70 steel

    Directory of Open Access Journals (Sweden)

    Flores, J. E.

    2012-10-01

    Full Text Available The corrosion behavior originated by sulfate-reducing bacteria (SRB was studied in two regions of welded API X-70 steel pipeline. The studies were focused on base material (BM and heat affected zone (HAZ, from the internal region of the pipe. SRB were extracted from oil and grown in a Postgate medium. Corrosion was evaluated at 60 °C for times between 5 and 64 days. Potentiodynamic polarization curves, obtained by electrochemical techniques, indicated surface activation at short times. Structural and morphological characterizations were carried out by scanning electron microscopy (SEM and optical microscopy (OM. H2S concentration and pH were also measured. Results showed an important increase in the corrosion damage up to 20 days, influenced by the SRB activity, which lead to a maximum of H2S (pH minimum. It was found a localized corrosion attack in the HAZ in a higher quantity compared to BM; and the formation of a thin film on the steel surface, originated by corrosion products and bacterial activity.

    El comportamiento ante la corrosión, originada por bacterias sulfato-reductoras (SRB, fue estudiado en dos regiones de un tubo de acero soldado API X-70. Los estudios se enfocaron en el material base (BM y la zona afectada térmicamente (HAZ, en la parte interna del tubo. Las SRB fueron extraídas del petróleo y cultivadas en un medio Postgate. El comportamiento a la corrosión fue evaluado a una temperatura de 60 °C, por periodos comprendidos entre 5 y 64 días. El análisis de las curvas de polarización potenciodinámicas, obtenidas por técnicas electroquímicas, indicó la activación de la superficie para tiempos cortos. La superficie fue caracterizada estructural y morfológicamente mediante microscopia electrónica de barrido (SEM, así como mediante microscopía óptica (OM. La concentración de H2S y el pH también fueron medidos. Los resultados mostraron un aumento importante de la corrosi

  10. A Fundamental study of remedial technology development to prevent stress corrosion cracking of steam generator tubing

    Energy Technology Data Exchange (ETDEWEB)

    Park, In Gyu; Lee, Chang Soon [Sunmoon University, Asan (Korea)

    1998-04-01

    Most of the PWR Steam generators with tubes in Alloy 600 alloy are affected by Stress Corrosion Cracking, such as PWSCC(Primary Water Stress Corrosion Cracking) and ODSCC(Outside Diameter Stress Corrosion Cracking). This study was undertaken to establish the background for remedial technology development to prevent SCC. in the report are included the following topics: (1) General: (i) water chemistry related factors, (ii) Pourbaix(Potential-pH) Diagram, (iii) polarization plot, (iv) corrosion mode of Alloy 600, 690, and 800, (v) IGA/SCC growth rate, (vi) material suspetibility of IGA/SCC, (vii) carbon solubility of Alloy 600 (2) Microstructures of Alloy 600 MA, Alloy 600 TT, Alloy 600 SEN Alloy 690 TT(Optical, SEM, and TEM) (3) Influencing factors for PWSCC initiation rate of Alloy 600: (i) microstructure, (ii) water chemistry(B, Li), (iii) temperature, (iv) plastic deformation, (v) stress relief annealing (4) Influencing factors for PWSCC growth rate of Alloy 600: (i) water chemistry(B, Li), (ii) Scott Model, (iii) intergranular carbide, (iv) temperature, (v) hold time (5) Laboratory conditions for ODSCC initiation rate: 1% NaOH, 316 deg C; 1% NaOH, 343 deg C; 50% NaOH, 288 deg C; 10% NaOH, 302 deg C; 10% NaOH, 316 deg C; 50% NaOH, 343 deg C (6) Sludge effects for ODSCC initiation rate: CuO, Cr{sub 2}O{sub 3}, Fe{sub 3}O{sub 4} (7) Influencing factors for PWSCC growth rate of Alloy 600: (i) Caustic concentration effect, (ii) carbonate addition effect (8) Sulfate corrosion: (i) sulfate ratio and pH effect, (ii) wastage rate of Alloy 600 and Alloy 690 (9) Crevice corrosion: (i) experimental setup for crevice corrosion, (ii) organic effect, (iii) (Na{sub 2}SO{sub 4} + NaOH) effect (10) Remedial measures for SCC: (i) Inhibitors, (ii) ZnO effect. (author). 30 refs., 174 figs., 51 tabs.

  11. A laboratory study of the effect of acetic acid vapor on atmospheric copper corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Delgado, A.; Cano, E.; Bastidas, J.M.; Lopez, F.A. [Centro Nacional de Investigaciones Metalurgicas, Madrid (Spain)

    1998-12-01

    A study was made of the copper corrosion rate and corrosion products originated by the action of acetic acid vapor at 100% relative humidity. Copper plates were exposed to an acetic acid contaminated atmosphere for a period of 21 days. Five acetic vapor concentration levels were used. The copper corrosion rate was in the range of 1 to 23 mg/dm{sup 2} day. The corrosion-product layers were characterized using electrochemical, X-ray powder diffraction, Fourier transform infrared spectrometry, and scanning electron microscopy techniques. Thermal and calorimetric studies were also performed. Some of the compounds identified were cuprite (Cu{sub 2}O), copper acetate hydrate [Cu(CH{sub 3}COO){sub 2}{center_dot}2H{sub 2}O], and copper hydroxide acetate [Cu{sub 4}(OH)(CH{sub 3}COO){sub 7}{center_dot}2H{sub 2}O]. This last compound was also characterized. The thickness of the patina layers was 4 to 8 nm for amorphous cuprite, 11 to 48 nm for cuprite, and 225 nm for copper acetate. The patina, in which the cementation process of different corrosion-product layers plays an important role, is formed by the reaction of acetic vapor with copper through porous cuprite paths.

  12. Integrated analytical methodologies for the study of corrosion processes in archaeological bronzes

    Energy Technology Data Exchange (ETDEWEB)

    Alberghina, Maria Francesca; Barraco, Rosita; Brai, Maria; Schillaci, Tiziano, E-mail: tschillaci@unipa.it; Tranchina, Luigi

    2011-02-15

    The investigations on structure and micro-chemical composition of archaeological metal alloys are needed in archaeometry. The aim of this study is devoted both to acquire information about their provenance and production technology, and to improve our understanding about the corrosion processes. In this paper we present the study of the corrosion phenomena of bronze samples, laboratory-made according to binary, ternary and quaternary alloys typical of Roman archaeometallurgical production through an integrated methodology based on the use of non or micro invasive physical techniques. Among the analysed samples, two were artificially aged through burial in the archaeological site of Tharros, along the west coast of Sardinia (Italy). The corrosion products, typical of the bronzes in archaeological sites near the sea, have been characterized by non invasive and micro-destructive measurements. In particular, the corrosion patinas were examined through optical microscopy, scanning electron microscopy and microanalysis, X-ray fluorescence and laser ablation spectroscopy. The use of integrated technologies allowed us to determine both the elemental composition and surface morphology of the patina, highlighting the correlation between patina nature and chemical composition of the burial context. Moreover, data obtained by the laser-induced breakdown spectroscopy along the depth profile on the samples, have yielded information about the stratigraphic layers of corrosion products and their growth. Finally, the depth profiles allowed us to verify both the chemical elements constituting the patina, the metal ions constituting the alloy and the occurrence of migration phenomena from bulk to the surface.

  13. Studies of corrosion morphologies by use of experiments and computer models

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, Terje

    1997-12-31

    CO{sub 2} corrosion of carbon steel is frequently encountered in the oil industry. This thesis studies the morphology of corroded metals and the dynamical evolution of corrosion attacks, especially pits and general corroded fronts, experimentally and by computerized simulation. Two experimental systems of carbon steel in CO{sub 2} bearing waters and aluminium in chloride containing electrolytes were used. Fractal geometry was used in analysing the corrosion patterns and found to be a fruitful technique. The position of the corroding fronts was obtained by destructive methods as well as non-destructive ones. To study fragile corrosion product layers or the corrosion process in situ, a grazing angle lighting technique was developed and found superior to other techniques. A computer model was developed that uses Monte Carlo technique to simulate the generation of localized pits and more general corroded front morphologies. A three-dimensional model and two versions of a two-dimensional model were developed. The three-dimensional model was used to provide incremental data of corroded volume and depth as a function of the simulation time. 185 refs., 97 figs., 16 tabs.

  14. A corrosion study of the ferrous medieval reinforcement of the Amiens cathedral. Phase characterisation and localisation by various microprobes techniques

    Energy Technology Data Exchange (ETDEWEB)

    Monnier, J. [SIS2M/LAPA-Laboratoire Pierre Suee, UMR 9956 CNRS - CEA, Bat. 637, CEA Saclay, 91191 Gif/Yvette cedex (France); Institut de Chimie et des Materiaux Paris-Est UMR 7182 CNRS - Universite Paris 12, 2-8 rue Henri Dunant, 94320 Thiais (France)], E-mail: monnier@icmpe.cnrs.fr; Neff, D. [SIS2M/LAPA-Laboratoire Pierre Suee, UMR 9956 CNRS - CEA, Bat. 637, CEA Saclay, 91191 Gif/Yvette cedex (France); Reguer, S. [Synchrotron SOLEIL, Saint-Aubin BP 4891192 Gif-sur-Yvette (France); Dillmann, P. [SIS2M/LAPA-Laboratoire Pierre Suee, UMR 9956 CNRS - CEA, Bat. 637, CEA Saclay, 91191 Gif/Yvette cedex (France); IRAMAT/LMC UMR 5060 CNRS and Laboratoire Pierre Suee UMR 9956 CNRS - CEA, Bat. 637, CEA Saclay, 91191 Gif-sur-Yvette, Cedex (France); Bellot-Gurlet, L. [Laboratoire de Dynamique, Interaction et Reactivite (LADIR), UMR 7075 CNRS - Universite Pierre et Marie Curie - Paris 6, 2 rue Henri Dunant, 94320 Thiais (France); Leroy, E. [Institut de Chimie et des Materiaux Paris-Est UMR 7182 CNRS - Universite Paris 12, 2-8 rue Henri Dunant, 94320 Thiais (France); Foy, E. [SIS2M/LAPA-Laboratoire Pierre Suee, UMR 9956 CNRS - CEA, Bat. 637, CEA Saclay, 91191 Gif/Yvette cedex (France); Legrand, L. [Laboratoire Analyse et Modelisation pour la biologie et l' Environnement, UMR 8587, CNRS-Universite d' Evry-CEA, Universite d' Evry Val d' Essonne, rue du Pere Jarland, 91025 Evry (France); Guillot, I. [Institut de Chimie et des Materiaux Paris-Est UMR 7182 CNRS - Universite Paris 12, 2-8 rue Henri Dunant, 94320 Thiais (France)

    2010-03-15

    In this study, long term corrosion mechanisms are approached through the characterisation of corrosion products formed on ancient artefacts over 500 years. Thirty-one artefacts were sampled in the Amiens cathedral. The thick corrosion product layers have been characterised at a microscopic scale by coupling complementary microbeam analytical techniques (SEM-EDS, Raman microspectroscopy, X-ray microdiffraction and microfluorescence, X-ray absorption microspectroscopy under synchrotron radiation). The main phase of the corrosion layer is goethite but lepidocrocite and akaganeite are also present locally in the corrosion layer. In addition, the presence of low crystallinity phases (feroxyhyte and/or ferrihydrite) is showed. These phases are electrochemically reactive, thus they could play a key role in the corrosion mechanisms.

  15. Corrosion Behaviour of A380 Aluminiun Alloy by Semi-Solid Rheocasting

    Science.gov (United States)

    Forn, A.; Rupérez, E.; Baile, M. T.; Campillo, M.; Menargues, S.; Espinosa, I.

    2007-04-01

    A comparative study was performed on the corrosion behavior of a component of A380 aluminium alloy obtained by Semi-Solid Rheocasting (SSR). The effect of heat treatments T5 and T6 on corrosion resistance was compared with components without heat treatment by SSR processes. Corrosion studies were performed using an acetic acid salt spray test, impedance measurements and polarization curves using a 3,5%Na Cl test solution. The corrosion progress is described by micrographic analysis.

  16. Glass-metal objects from archaeological excavation: corrosion study

    Science.gov (United States)

    Greiner-Wronowa, Elżbieta; Zabiegaj, Dominika; Piccardo, Paolo

    2013-12-01

    This paper contributes to the investigations on history, technology, and degradation of middle age objects (metallic rings with mounted glass beads) recently excavated under the Main Square in Krakow (Poland). Moreover, they were discovered in soil layers differing by chemical composition and microclimate parameters. Historical material is indeed very limited in terms of quantity and sample size, and the following nondestructive analyses were applied: scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS), X-ray diffraction (XRD), and X-ray fluorescence spectroscopy (XRF). The glass and the metal were separately tested. Metallography on cross-sections (by both optical and scanning electron microscopy) was applied only on microfragments sampled from metallic rings. The achieved results pointed out how the local microclimate affected the degradation of the analyzed rings developing locally different corrosion processes. Each tested glass of "ring eye" shows a specific chemical composition. All glass pieces were covered by silica gel, and locally more advanced corrosion has been found.

  17. Evaluation of the corrosion resistance of latex modified concrete (LMC)

    Energy Technology Data Exchange (ETDEWEB)

    Okba, S.H.; El-Dieb, A.S.; Reda, M.M. [Ain Shams Univ., Cairo (Egypt). Dept. of Structural Engineering

    1997-06-01

    In recent years, various reinforced concrete structures worldwide have suffered rapid deterioration. Therefore, durability of concrete structures especially those exposed to aggressive environments is of great concern. Many deterioration causes and factors have been investigated. Corrosion of steel reinforcement was found to be one of the major deterioration problems. Penetration of chloride ions is one of the main causes which induces corrosion. The objective of this study is to evaluate the corrosion resistance of latex modified concrete (LMC) compared to conventional concrete using an accelerated corrosion cell. The corrosion cell proved to be a good and simple method to evaluate the durability of concretes especially with respect to chloride ion penetration, and the protection of reinforcement against corrosion. The LMC proved to be superior in its corrosion resistance compared to conventional concrete, which recommends its use in structures exposed to severe aggressive environments.

  18. Fundamental Studies of the Role of Grain Boundaries on Uniform Corrosion of Advanced Nuclear Reactor Materials

    Energy Technology Data Exchange (ETDEWEB)

    Taheri, Mitra [Drexel Univ., Philadelphia, PA (United States); Motta, Arthur [Pennsylvania State Univ., University Park, PA (United States); Marquis, Emmanuelle [Univ. of Michigan, Ann Arbor, MI (United States)

    2016-05-20

    The main objective of this proposal is to develop fundamental understanding of the role of grain boundaries in stable oxide growth. To understand the process of oxide layer destabilization, it is necessary to observe the early stages of corrosion. During conventional studies in which a sample is exposed and examined after removal from the autoclave, the destabilization process will normally have already taken place, and is only examined post facto. To capture the instants of oxide destabilization, it is necessary to observe it in situ; however, significant questions always arise as to the influence of the corrosion geometry and conditions on the corrosion process. Thus, a combination of post facto examinations and in situ studies is proposed, which also combines state-of-the-art characterization techniques to derive a complete understanding of the destabilization process and the role of grain boundaries.

  19. Study of corrosion of aluminium alloys of nuclear purity in ordinary water, пart one

    Directory of Open Access Journals (Sweden)

    Pešić Milan P.

    2004-01-01

    Full Text Available Effects of corrosion of aluminum alloys of nuclear purity in ordinary water of the spent fuel storage pool of the RA research reactor at VINČA Institute of Nuclear Sciences has been examined in the frame work of the International Atomic Energy Agency Coordinated Research Project "Corrosion of Research Reactor Aluminum-Clad Spent Fuel in Water" since 2002. The study presented in this paper comprises activities on determination and monitoring of chemical parameters and radio activity of water and sludge in the RA spent fuel storage pool and results of the initial study of corrosion effects obtained by visual examinations of surfaces of various coupons made of aluminum alloys of nuclear purity of the test racks exposed to the pool water for a period from six months to six years.

  20. Study of corrosion protection of the composite fdms on A356 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    SUN Huanhuan; WANG Hui; MENG Fanling

    2011-01-01

    Composite films were fabricated on A356 aluminum alloy by combined anodizing and rare earth deposition.The corrosion protection effect and corrosion behavior of the composite films in 3.5% NaC1 solution were studied by electrochemical impedance spectroscopy (EIS).SEM observation indicated that the rare earth Ce film completely sealed the porous structure of the anodic film,and the composite films composed of anodic film and Ce film were compact and integrated.According to the characteristics of EIS,the EIS plots of the composite films at different immersion times were simulated using the equivalent circuits of Rsol(QceRce)(QaRa),Rsol(QceRce)(QpRp)(QbRb) and Rsol(QpRp)(QbRb) models,respectively.The test results showed that the Ce film at the outer layer of the composite films had good protection effect at the initial stage of the immersion corrosion.It effectively helped the anodie film at the inner layer to prevent chloride irons from penetrating the aluminum alloy matrix.After 18 days,the Ce film lost its anticorrosive property,and the anodic film took the leading role of the corrosion protection.When the corrosion time was up to 42 days,the aluminum matrix was not corroded yet.Thus,the higher protection degree of the composite films for A356 aluminum alloy was attributed to the synergism effects of anodic film and rare earth Ce film.

  1. Experimental and modeling study of chloride ingress into concrete and reinforcement corrosion initiation

    Science.gov (United States)

    Yu, Hui

    Effects of reinforcement and coarse aggregate on chloride ingression into concrete and reinforcement corrosion initiation have been studied with experimental and modeling (finite element method) analyses. Once specimens were fabricated and exposed to a chloride solution, various experimental techniques were employed to determine the effect of reinforcement and coarse aggregate on time-to-corrosion and chloride ingress and concentration at corrosion locations. Model analyses were performed to verify and explain the experimental results. Based upon the results, it was determined that unexpectedly higher chloride concentrations were present on the top of the rebar trace than that to the side at the same depth and an inverse concentration gradient (increasing [ Cl-] with increasing depth) occurred near the top of rebars. Also, coarse aggregate volume profile in close proximity to the rebar and spatial distribution of these aggregates, in conjunction with the physical obstruction afforded by reinforcement to chloride flow, complicates concrete sampling for Cl- intended to define the critical concentration of this species to initiate corrosion. Modeling analyses that considered cover thickness, chloride threshold concentration, reinforcement size and shape, and coarse aggregate type and percolation confirmed the experimental findings. The results, at least in part, account for the relatively wide spread in chloride corrosion threshold values reported in the literature and illustrate that more consistent chloride threshold concentrations can be acquired from mortar or paste specimens than from concrete ones.

  2. An X-ray diffraction study of corrosion products from low carbon steel

    Directory of Open Access Journals (Sweden)

    Morales, A. L.

    2003-12-01

    Full Text Available It was found in earlier work a decrease in the corrosion rate from low carbon steel when it was subjected to the action of a combined pollutant concentration (SO4-2 = 10-4 M + Cl- = 1.5 x 10-3 M. It was also found that large magnetite content of the rust was related to higher corrosion rates. In the present study corrosion products are further analyzed by means of X-ray diffraction to account for composition changes during the corrosion process. It is found that lepidocrocite and goethite are the dominant components for the short-term corrosion in all batches considered while for long-term corrosion lepidocrite and goethite dominates if the corrosion rate is low and magnetite dominates if the corrosion rate is high. The mechanism for decreasing the corrosion rate is related to the inhibition of magnetite production at this particular concentration.

    En un estudio anterior se encontró que la tasa de corrosión, de un acero al carbono, decrecía cuando se le sometía al efecto combinado de una mezcla de contaminantes (SO4-2 = 10-4 M + Cl- = 1,5 x 10-3 M. También, se concluyó que altos contenidos de magnetita en la herrumbre estaban asociados a altas tasas de corrosión. En este trabajo se retoman estas herrumbres para analizarlas por difractometría de rayos X para tomar en cuenta los cambios en composición durante el proceso corrosivo. Se encuentra que goethita y lepidocrocita son las componentes dominantes durante la etapa inicial del proceso en todos los experimentos. En cambio para tiempos largos de exposición, y si la tasa de corrosión es alta, la magnetita es el producto de corrosión dominante. El mecanismo que reduce la tasa de corrosión, en la mezcla mencionada anteriormente, está relacionado con la inhibición del proceso de producción de la magnetita en estas condiciones.

  3. Study of the Intercrystalline Corrosion in Pipes of Stainless Steel in a Combined Cycle

    Directory of Open Access Journals (Sweden)

    Raúl Andrés Montejo Serrano

    2014-09-01

    Full Text Available The present work is carried out with the purpose of giving answer to the possible presence ofintercrystalline corrosion and its future consequences in the built tubes of stainless steel 304L anddedicated to the conduction from the water to the boilers of a combined cycle of electricity production.The plant is these in this moments in installation of process investor and assembly and this study wasrequested since during the trial of installation of the pipes of stainless steel that will drive the watertried to the steam generators, they were detected on the part of the operatives some imperfections inthe material, what generated the doubt about the possibility of presence of intercrystalline corrosion orof another type in the pipes. After the realized rehearsals according to international norms and alsousing rehearsals metallography you concludes that the material employee is not sensitive to this typeof corrosion.

  4. Study of Pitting Corrosion Behavior of FSW weldments of AA6101- T6 Aluminium Alloy

    Directory of Open Access Journals (Sweden)

    L.V. Kamble

    2015-09-01

    Full Text Available Friction Stir Welding (FSW is a promising solid state joining process widely used generally for Al alloys, especially in aerospace, marine and automobile applications. In present work, the microstructure and corrosion behavior of friction stir welded AA6101 T6 Al alloy is studied. The friction stir welding was carried using vertical milling machine with different tool rotational speeds and welding speeds. The microstructure at weld nugget or stir zone (SN, thermo-mechanically affected zone (TMAZ, heat affected zone (HAZ and base metal were observed using optical microscopy. The corrosion tests of base alloy and welded joints were carried out in 3.5% NaCl solution at temperature of 30º C. Corrosion rate and emf were determined using cyclic polarization measurement.

  5. Laboratory Study of High Temperature Corrosion in Straw-fired Power Plants

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Maahn, Ernst emanuel

    1997-01-01

    The components contributing to corrosion, HCl(g)SO2(g), KCl and K2SO4 were studied in the laboratory for Sandvik 8LR30 and Sanicro 28. The influence of HCl and SO2 was investigated at 600C material temperature and 600/800C flue gas temperature at time intervals up to 300 hours. The influence of ash...... deposits in air was examined at 525C-700C. Finally exposures were undertaken combining the aforementioned aggressive gas environment with the ash deposits. Thus the corrosion potential of individual components were evaluated and also whether they had a synergistic, antagonistic or additive effect on one...... another to influence the overall corrosion rate....

  6. Study on Mitigation Method of Solder Corrosion for Crystalline Silicon Photovoltaic Modules

    Directory of Open Access Journals (Sweden)

    Ju-Hee Kim

    2014-01-01

    Full Text Available The corrosion of 62Sn36Pb2Ag solder connections poses serious difficulties for outdoor-exposed photovoltaic (PV modules, as connection degradation contributes to the increase in series resistance (RS of PV modules. In this study, we investigated a corrosion mitigation method based on the corrosion mechanism. The effect of added sacrificial metal on the reliability of PV modules was evaluated using the oxidation-reduction (redox reaction under damp heat (DH conditions. Experimental results after exposure to DH show that the main reason for the decrease in power was a drop in the module’s fill factor. This drop was attributed to the increase of RS. The drop in output power of the PV module without added sacrificial metal is greater than that of the sample with sacrificial metal. Electroluminescence and current-voltage mapping analysis also show that the PV module with sacrificial metal experienced less degradation than the sample without sacrificial metal.

  7. Case study of a fast propagating bacteriogenically induced concrete corrosion in an Austrian sewer system

    Science.gov (United States)

    Grengg, Cyrill; Mittermayr, Florian; Baldermann, Andre; Böttcher, Michael; Leis, Albrecht; Koraimann, Günther; Dietzel, Martin

    2015-04-01

    Reaction mechanisms leading to microbially induced concrete corrosion (MICC) are highly complex and often not fully understood. The aim of the present case study is to contribute to a deeper understanding of reaction paths, environmental controls, and corrosion rates related to MICC in a modern Austrian sewer system by introducing an advanced multi proxy approach that comprises gaseous, hydro-geochemical, bacteriological, and mineralogical analyses. Various crucial parameters for detecting alteration features were determined in the field and laboratory, including (i) temperature, pH, alkalinity, chemical compositions of the solutions, (ii) chemical and mineralogical composition of solids, (iii) bacterial analysis, and (iv) concentrations of gaseous H2S, CH4 and CO2 within the sewer pipe atmosphere. An overview of the field site and analytical results, focusing on reaction mechanisms causing the corrosion, as well as possible remediation strategies will be presented.

  8. Photoelectrochemical Study of Corrosion Resisting Property of Cupronickel B10 in Simulated Cooling Water

    Institute of Scientific and Technical Information of China (English)

    XU Qunjie; WAN Zongyue; ZHOU Guoding; YIN Renhe; CAO Weimin; LIN Changjian

    2009-01-01

    The corrosion behavior for cupronickel B10 electrode in simulated cooling water has been studied by using cyclic voltammetry, a photocurrent response method and electrochemical impedance spectroscopy (EIS). The cupronickel electrode shows a p-type photoresponse to positive and negative potential scan, which comes from Cu2O layer on its surface, but its Iph.max is less than that in borax buffer solution. The corrosion resisting property of the cupronickel B10 electrode appeared worse with the increase in the concentrations of Cl-, SO2-4 and S2 ions, as well as with increasing pH. The rise in the temperature may result in a photoresponse changes from p-type to n-type, and the corrosion resisting property fell simultaneously. The results of the EIS measurement agree well with those obtained by a photoelectrochemical method.

  9. Micromechanical study of corrosion products layers. Part I: Experimental characterization

    Energy Technology Data Exchange (ETDEWEB)

    Dehoux, A., E-mail: dehoux@lmt.ens-cachan.fr [UPMC Univ., Paris 06, LMT-Cachan (ENS Cachan/UMR8535/UPMC) (France); Andra, Agence Nationale pour la gestion des Dechets RadioActifs, 1-7 rue Jean Monnet, parc de la croix blanche, 92298 Chatenay Malabry Cedex (France); Bouchelaghem, F.; Berthaud, Y. [UPMC Univ., Paris 06, LMT-Cachan (ENS Cachan/UMR8535/UPMC) (France); Neff, D. [SIS2M/LAPA-Laboratoire Pierre Suee, UMR 9956 CNRS, CEA, Bt. 637, CEA Saclay, 91191 Gif/Yvette (France); L' Hostis, V. [DEN, DANS, DPC, SCCME, Laboratoire d' Etude du Comportement des Betons et des Argiles, F-91191 Gif/Yvette (France)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer The mechanical characterization of oxide formed on ancient ferrous artefacts has been performed. Black-Right-Pointing-Pointer The main phases present are goethite, magnetite and maghemite. Black-Right-Pointing-Pointer Typical ranges of the local mechanical properties can be related with the main phases present. Black-Right-Pointing-Pointer The Young moduli at the micrometric scale vary between 50 and 200 GPa. Black-Right-Pointing-Pointer Time dependent effects are negligible. - Abstract: A micromechanical characterization had been performed on ancient artefacts corrosion products. The proposed experimental approach allies scanning electron microscopy observations, micro-indentation tests which allow the characterization of the local stiffness of elementary constituents, and finally Raman micro-spectroscopy tests which give access to the local crystallised phases of the samples. The experimental campaign contains a large series of tests, which give us the opportunity to interpret the dispersion of local stiffness measurements.

  10. Quantum chemical study on the corrosion inhibition property of some heterocyclic azole derivatives

    Directory of Open Access Journals (Sweden)

    N. Anusuya

    2015-09-01

    Full Text Available Quantum chemical calculations based on density functional theory (DFT method were performed on heterocyclic azole derivatives as corrosion inhibitors for mild steel in acid media to investigate the relationship between molecular structure of the inhibitors and the corresponding inhibition efficiencies (%. Quantum chemical parameters most relevant to their potential action as corrosion inhibitors have been calculated in the non-protonated and protonated forms in aqueous phase for comparison. Results obtained in this study indicate thatin acidic media, both the protonated and non-protonated forms of the azoles represent the better actual experimental situation.

  11. Stress corrosion study of PH13-8Mo stainless steel using the Slow Strain Rate Technique

    Science.gov (United States)

    Torres, Pablo D.

    1989-01-01

    The need for a fast and reliable method to study stress corrosion in metals has caused increased interest in the Slow Strain Rate Technique (SSRT) during the last few decades. PH13-8MoH950 and H1000 round tensile specimens were studied by this method. Percent reduction-in-area, time-to-failure, elongation at fracture, and fracture energy were used to express the loss in ductility, which has been used to indicate susceptibility to stress corrosion cracking (SCC). Results from a 3.5 percent salt solution (corrosive medium) were compared to those in air (inert medium). A tendency to early failure was found when testing in the vicinity of 1.0 x 10(-6) mm/mm/sec in the 3.5 percent salt solution. PH13-8Mo H1000 was found to be less likely to suffer SCC than PH13-8Mo H950. This program showed that the SSRT is promising for the SCC characterization of metals and results can be obtained in much shorter times (18 hr for PH steels) than those required using conventional techniques.

  12. A study of early corrosion behaviors of FeCrAl alloys in liquid lead-bismuth eutectic environments

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jun [Nuclear Transmutation Energy Research Center of Korea (NUTRECK), Seoul National University, San 56-1 Shinlim-dong, Gwanak-ku, Seoul 151-742 (Korea, Republic of); Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology, 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of); Nam, Hyo On; Hwang, Il Soon [Nuclear Transmutation Energy Research Center of Korea (NUTRECK), Seoul National University, San 56-1 Shinlim-dong, Gwanak-ku, Seoul 151-742 (Korea, Republic of); Kim, Ji Hyun, E-mail: kimjh@unist.ac.k [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology, 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of)

    2010-12-31

    Lead and lead-bismuth eutectic (LBE) alloy have been increasingly receiving attention as heavy liquid metal coolants (HLMC) for future nuclear energy systems. The compatibility of structural materials and components with lead-bismuth eutectic liquid at high temperature is one of key issues for the commercialization of lead fast reactors. In the present study, the corrosion behaviors of iron-based alumina-forming alloys (Kanthal-AF (registered) , PM2000, MA956) were investigated by exposing to stagnant LBE environments at 500 {sup o}C and 550 {sup o}C for up to 500 h. After exposures, the thickness and chemistry of the oxide layer on the specimens were analyzed by scanning electron microscopy, scanning transmission electron microscopy and energy dispersive X-ray spectroscopy. As a result, the oxide characteristics and the corrosion resistance were compared. In this study, it was shown that the corrosion resistance of FeCrAl ODS steels (PM2000, MA956) are superior to that of FeCrAl ferritic steel (Kanthal-AF (registered)) in higher temperature LBE.

  13. Corrosion studies using potentiodynamic and EIS electrochemical techniques of welded lean duplex stainless steel UNS S82441

    Science.gov (United States)

    Brytan, Z.; Niagaj, J.; Reiman, Ł.

    2016-12-01

    The corrosion characterisation of lean duplex stainless steel (1.4662) UNS S82441 welded joints using the potentiodynamic test and electrochemical impedance spectroscopy in 1 M NaCl solution are discussed. The influence of autogenous TIG welding parameters (amount of heat input and composition of shielding gases like Ar and Ar-N2 and an Ar-He mixture), as well as A-TIG welding was studied. The influence of welding parameters on phase balance, microstructural changes and the protective properties of passive oxide films formed at the open circuit potential or during the anodic polarisation were studied. From the results of the potentiodynamic test and electrochemical impedance spectroscopy of TIG and A-TiG, welded joints show a lower corrosion resistance compared to non-welded parent metal, but introducing heat input properly during welding and applying shielding gases rich in nitrogen or helium can increase austenitic phase content, which is beneficial for corrosion resistance, and improves surface oxide layer resistance in 1 M NaCl solution.

  14. Corrosion-fatigue study of a Zr-based bulk-metallic glass in a physiologically relevant environment

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Lu [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, XueYuan Road No. 37, HaiDian District, Beijing 100191 (China); Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996-2200 (United States); Wang, Gongyao; Qiao, Dongchun; Liaw, Peter K. [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996-2200 (United States); Pang, Shujie; Wang, Jianfeng [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, XueYuan Road No. 37, HaiDian District, Beijing 100191 (China); Zhang, Tao, E-mail: zhangtao@buaa.edu.c [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, XueYuan Road No. 37, HaiDian District, Beijing 100191 (China)

    2010-08-15

    Four-point-bend corrosion-fatigue experiments were conducted in a physiologically relevant environment to study the environmental effects on the fatigue behavior of (Zr{sub 0.55}Al{sub 0.10}Ni{sub 0.05}Cu{sub 0.30}){sub 99}Y{sub 1} (at.%) bulk-metallic glasses (BMGs), and the results were compared with those obtained in air at room temperature. At high stress ranges, the corrosive environment did not significantly affect the fatigue lifetime; while at low stress ranges, the corrosive environment exhibited a detrimental effect on the fatigue resistance. The fatigue strength was decreased by 40% in the physiologically relevant environment. Fracture morphologies after fatigue tests were studied by the scanning electron microscopy. The mechanism for the environmental effects on the fatigue life of the (Zr{sub 0.55}Al{sub 0.10}Ni{sub 0.05}Cu{sub 0.30}){sub 99}Y{sub 1} BMG was determined to be anodic dissolution.

  15. A study of the effects of phosphates on copper corrosion in drinking water: Copper release, electrochemical, and surface analysis approach

    Science.gov (United States)

    Kang, Young C.

    The following work is the study to evaluate the impact of corrosion inhibitors on the copper metal in drinking water and to investigate the corrosion mechanism in the presence and absence of inhibitors. Electrochemical experiments were conducted to understand the effect of specific corrosion inhibitors in synthetic drinking water which was prepared with controlled specific water quality parameters. Water chemistry was studied by Inductively Coupled Plasma--Atomic Emission Spectroscopy (ICP--AES) to investigate the copper leaching rate with time. Surface morphology, crystallinity of corrosion products, copper oxidation status, and surface composition were characterized by various solid surface analysis methods, such as Scanning Electron Microscopy/Energy--Dispersive Spectrometry (SEM/EDS), Grazing-Incidence-angle X-ray Diffraction (GIXRD), X-ray Photoelectron Spectroscopy (XPS), and Time-of-Flight Secondary Ions Mass Spectrometry (ToF-SIMS). The purpose of the first set of experiments was to test various electrochemical techniques for copper corrosion for short term before studying a long term loop system. Surface analysis techniques were carried out to identify and study the corrosion products that form on the fresh copper metal surface when copper coupons were exposed to test solutions for 2 days of experiments time. The second phase of experiments was conducted with a copper pipe loop system in a synthetic tap water over an extended period of time, i.e., 4 months. Copper release and electrochemically measured corrosion activity profiles were monitored carefully with and without corrosion inhibitor, polyphosphate. A correlation between the copper released into the solution and the electrochemically measured corrosion activities was also attempted. To investigate corrosion products on the copper pipe samples, various surface analysis techniques were applied in this study. Especially, static mass spectra acquisition and element distribution mapping were carried out

  16. A Comparative Study of Teaching Comparative Education

    OpenAIRE

    2007-01-01

    The purpose of this paper is to characterize the comparative education subjects offered in different programs in different foreign universities. As a subject, comparative education has not been firmly institutionalized in education programs in Japanese universities. There was a movement which aimed at making comparative education as one of the mandatory subjects in the teacher training program, however it was not successful. To date, comparative education subject has been offered in various p...

  17. Effect of plane surface and wrinkly surface of pure Titanium on corrosion resistance and bacterium accumulation:an in vivo study

    Institute of Scientific and Technical Information of China (English)

    李笑梅; 汪大林; 郭天文; 齐文胜

    2004-01-01

    Objective: To study the effect of surface configuration on the corrosion resistance and bacterium accumulation of pure Titanium(Ti) when used in oral environment. Methods: Six edentulous volunteers with healthy oral mucosa participated in an in vivo study. Two kinds of pure Ti testing pieces with plane and wrinkly surface were fixed in the polished surface of upper complete dentures. After 6-month wearing, dynamic polarization curves were traced with electrochemical oral cavity was higher than that left in air, which meant corrosion resistance falling. Compared to plane one, Ecorr of wrinkly put a significant influence on amount of bacterium adhered on pure Titanium, but had no relation to species of bacterium. To the same patient, wrinkly samples collected more bacterium than plane ones, and exhibited G- coccus beside G+ coccus.Conclusion: From the perspective of corrosion behavior and benefit to periodontal tissue, wrinkly surface should not be adopted when pure Ti prosthesis is made, especially on connector part of denture.

  18. Comparison of corrosion behavior of ZL104 alloy at as-cast and heat treatment states

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The corrosion behavior of ZL 104 alloy at different states (as-cast and heat treatment) in salt spray corrosion (SSC) was studied. The results show that the sample treated after refinement and modification has the least corrosive resistance compared with the sample bearing as-cast structure at the beginning of the corrosion. As the corrosion process continued, however, the trend reversed itself. After 44 h continuous corrosion, the corrosive rates of all samples tend to be stable. After experiments, the sample bearing as-cast structure had the most corrosive products on the surface whereas the sample being refined and modified had the least products. The Fourier transformation infrared spectroscopy (FTIR)analyses of the corrosion products show that these products are composed of hydroxyl-containing substances.

  19. Experimental and theoretical studies of xanthan gum and its graft co-polymer as corrosion inhibitor for mild steel in 15% HCl

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Amrita; Pal, Sagar; Udayabhanu, G., E-mail: g_udayabhanu@hotmail.com

    2015-10-30

    Highlights: • Xanthan gum and its graft co-polymer used as corrosion inhibitors for mild steel in 15% HCl. • Electrochemical and weight loss studies give comparable corrosion rates. • Both the inhibitors are mixed type in nature. • Modified graft co-polymer is a more effective corrosion inhibitor. • Theoretical calculations taking monomer units of the polymer support the experimental results. - Abstract: Xanthan gum (XG) and its graft co-polymer have been investigated as corrosion inhibitors for mild steel in 15% HCl. Gravimetric analysis, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods were employed for investigating the effectiveness of these inhibitors. Results indicate that both the inhibitors are of mixed type and follow Langmuir adsorption isotherm. Scanning electron microscopy (SEM) study also confirmed the protection of the metal surface by XG and xanthan gum-graft-poly(acrylamide) (XG-g-PAM). Theoretical calculations using Density Functional Theory (DFT) were used to establish the correlation between the structure and corrosion protection efficiencies.

  20. Corrosion susceptibility study of candidate pin materials for ALTC (Active Lithium/Thionyl Chloride) batteries

    Science.gov (United States)

    Bovard, Francine S.; Cieslak, Wendy R.

    1987-09-01

    The corrosion susceptibilities of eight alternate battery pin material candidates for ALTC (Active Lithium/Thionyl Chloride) batteries in 1.5M LiAlCl4/SOCl2 electrolyte have been investigated using ampule exposure and electrochemical tests. The thermal expansion coefficients of these candidate materials are expected to match Sandia-developed Li-corrosion resistant glasses. The corrosion resistances of the candidate materials, which included three stainless steels (15-5 PH, 17-4 PH, and 446), three Fe-Ni glass sealing alloys (Kovar, Alloy 52, and Niromet 426), a Ni-based alloy (Hastelloy B-2) and a zirconium-based alloy (Zircaloy), were compared to the reference materials Ni and 316L SS. All of the candidate materials showed some evidence of corrosion and, therefore, did not perform as well as the reference materials. The Hastelloy B-2 and Zircaloy are clearly unacceptable materials for this application. Of the remaining alternate materials, the 446 SS and Alloy 52 are the most promising candidates.

  1. Novel time–frequency characterization of electrochemical noise data in corrosion studies using Hilbert spectra

    NARCIS (Netherlands)

    Homborg, A.M.; Westing, E.P.M.; Tinga, Tiedo; Zhang, X; Oonincx, P.J.; Ferrari, G.M.; de Wit, J.H.W.; Mol, J.M.C.

    2013-01-01

    Hilbert spectra, calculated with the Hilbert–Huang transform, are presented here as an analysis technique for the characterization of electrochemical noise data in corrosion studies. A highly detailed decomposition of the original current and potential data is provided in time and frequency

  2. Surface Studies of Ultra Strength Drilling Steel after Corrosion Fatigue in Simulated Sour Environment

    Energy Technology Data Exchange (ETDEWEB)

    M. Ziomek-Moroz; J.A. Hawk; R. Thodla; F. Gui

    2012-05-06

    The Unites States predicted 60% growth in energy demand by 2030 makes oil and natural gas primary target fuels for energy generation. The fact that the peak of oil production from shallow wells (< 5000 m) is about to be reached, thereby pushing the oil and natural gas industry into deeper wells. However, drilling to depths greater than 5000 m requires increasing the strength-to weight ratio of the drill pipe materials. Grade UD-165 is one of the ultra- high yield strength carbon steels developed for ultra deep drilling (UDD) activities. Drilling UDD wells exposes the drill pipes to Cl{sup -}, HCO{sub 3}{sup -}/CO{sub 3}{sup 2-}, and H{sub 2}S-containig corrosive environments (i.e., sour environments) at higher pressures and temperatures compared to those found in conventional wells. Because of the lack of synergism within the service environment, operational stresses can result in catastrophic brittle failures characteristic for environmentally assisted cracking (EAC). Approximately 75% of all drill string failures are caused by fatigue or corrosion fatigue. Since there is no literature data on the corrosion fatigue performance of UD-165 in sour environments, research was initiated to better clarify the fatigue crack growth (FCGR) behavior of this alloy in UDD environments. The FCGR behavior of ultra-strength carbon steel, grade UD-165, was investigated by monitoring crack growth rate in deaerated 5%NaCl solution buffered with NaHCO{sub 3}/Na{sub 2}CO{sub 3} and in contact with H{sub 2}S. The partial pressure of H{sub 2}S (p{sub H2S}) was 0.83 kPa and pH of the solution was adjusted by NaOH to 12. The fatigue experiments were performed at 20 and 85 C in an autoclave with surface investigations augmented by scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) spectroscopy. In this study, research focused on surface analyses supported by the fatigue crack growth rate measurements. Fig. 1 shows an SEM micrograph of the crack that propagated from the

  3. Study on possibility for the improvement of corrosion resistance of metals using laser-formed oxide surface structure

    Science.gov (United States)

    Ruzankina, J. S.; Vasiliev, O. S.

    2016-08-01

    The laser processes of oxidation are currently known and used extensively, in particular, to improve corrosion resistance of metals possessing certain properties and composition. In this regard, actuality is the methods of laser oxidation of metals and the determination of their modes of treatment in each specific case. Increase of corrosion resistance ST20 can carried out with the formation on the surface oxide films, as well as by reducing surface roughness. Studied various modes of processing of the steel surface. Corrosion resistance investigated for protecting a metal. Defocusing the beam to allow the surface treatment of a wide beam in the low temperature mode of processing. For further study of the irradiated surface on the corrosion resistance was conducted by chemical treatment in acid. Estimated phase composition of films formed under laser treatment simulated in the program astics. The study to increase the corrosion resistance of steel and titanium, have shown that under the chosen methods of processing of materials degradation observed.

  4. Long-term corrosion study at nuclear power plant Bohunice (Slovakia)

    Science.gov (United States)

    Slugen, V.; Lipka, J.; Dekan, J.; Tóth, I.; Smieško, I.

    2010-03-01

    Steam generators of four VVER-440 units at nuclear power plants V-1 and V-2 in Jaslovske Bohunice (Slovakia) were gradually changed by new original "Bohunice" design in period 1994-1998. Corrosion processes before and after these design and material changes in Bohunice secondary circuit were studied using Mössbauer spectroscopy during last 25 years. Innovations in the feed water pipeline design as well as material composition improvements were evaluated positively. Mössbauer spectroscopy studies of phase composition of corrosion products were performed on real specimens scrapped from water pipelines or in form of filter deposits. The corrosion of new feed water pipelines system (from austenitic steel) in combination to innovated operation regimes goes dominantly to magnetite. The hematite presence is mostly on the internal surface of steam generator body and its concentration increases towards the top of the body. In the results interpretation it is necessary to consider also erosion as well as scope and type of maintenance activities. The long-term study of phase composition of corrosion products at VVER reactors is one of precondition for the safe operation over the projected NPP lifetime.

  5. Long-term corrosion study at nuclear power plant Bohunice (Slovakia)

    Energy Technology Data Exchange (ETDEWEB)

    Slugen, V; Lipka, J; Dekan, J; Toth, I [Department of Nuclear Physics and Technology, Slovak University of Technology Bratislava, Ilkovicova 3, 812 19 Bratislava (Slovakia); Smiesko, I, E-mail: Vladimir.Slugen@stuba.s [NPP Jaslovske Bohunice, SE, a.s. (Slovakia)

    2010-03-01

    Steam generators of four VVER-440 units at nuclear power plants V-1 and V-2 in Jaslovske Bohunice (Slovakia) were gradually changed by new original 'Bohunice' design in period 1994-1998. Corrosion processes before and after these design and material changes in Bohunice secondary circuit were studied using Moessbauer spectroscopy during last 25 years. Innovations in the feed water pipeline design as well as material composition improvements were evaluated positively. Moessbauer spectroscopy studies of phase composition of corrosion products were performed on real specimens scrapped from water pipelines or in form of filter deposits. The corrosion of new feed water pipelines system (from austenitic steel) in combination to innovated operation regimes goes dominantly to magnetite. The hematite presence is mostly on the internal surface of steam generator body and its concentration increases towards the top of the body. In the results interpretation it is necessary to consider also erosion as well as scope and type of maintenance activities. The long-term study of phase composition of corrosion products at VVER reactors is one of precondition for the safe operation over the projected NPP lifetime.

  6. Corrosion of carbon-alloyed iron aluminides

    Indian Academy of Sciences (India)

    M Sen; R Balasubramaniam; A V Ramesh Kumar

    2000-10-01

    The corrosion behaviour of two carbon-alloyed intermetallics of composition Fe–28.1Al–2.1C and Fe–27.5Al–3.7C has been studied and compared with that of binary intermetallics. Potentiodynamic polarization studies indicated that the intermetallics exhibited active–passive behaviour in an acidic solution of pH = 1, whereas they exhibited stable passivity in a buffer solution of pH 8.4. Corrosion rates were also obtained by immersion testing. The variation of corrosion rate as a function of time was similar for both the intermetallics. The variation in corrosion rate as a function of time has been explained based on the observed potentiodynamic polarization behaviour. Scanning electron microscopy of corroded surfaces indicated that the carbon-alloyed intermetallics were susceptible to galvanic corrosion, due to the presence of carbides.

  7. Embrittlement and anodic process in stress corrosion cracking: study of the influent micro-mechanical parameters; Fragilisation et processus anodiques en corrosion sous contrainte: etude des parametres micro-mecaniques influents

    Energy Technology Data Exchange (ETDEWEB)

    Tinnes, J.Ph

    2006-11-15

    We study the influence of local mechanical parameters on crack propagation in Stress Corrosion Cracking, at the scale of the microstructure. Two systems are compared: the CuAl{sub 9}Ni{sub 3}Fe{sub 2} copper-aluminium alloy in synthetic sea water under cathodic polarization, where the crack propagation mechanism is related to strain-assisted anodic dissolution, and the 316L austenitic stainless steel in MgCl{sub 2} solution, where embrittlement mechanisms related to hydrogen effects prevail. We use micro-notched tensile specimen that allow to study isolated short cracks. These experiments are modelled by means of finite elements calculations, and further characterized by Electron Back scattered Diffraction (EBSD) in the case of the 316L alloy. In terms of the local mechanical parameters that control propagation, fundamental differences are outlined between the two systems. They are discussed from the viewpoint of the available models of Stress Corrosion Cracking. (author)

  8. Study of the Corrosion Resistance of Electroless Ni-P Deposits in a Sodium Chloride Medium

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The corrosion resistance of electroless Ni-P deposits with phosphorous contents from 12% to 14% in sodium chloride solutions was studied. The deposits were immersed in 3.5% NaCl solutions for 29 d to obtain the electrochemical parameters and were examined in a standard salt spray test for 15 d respectively. The corrosion resistance of the deposits was studied by potentio-dynamic scan, electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD) and cold-field emission scanning electron microscopy (FE-SEM) equipped with an energy dispersive X-ray detector (EDX). The patterns of XRD and the results of FE-SEM showed that the prepared deposits were amorphous. But after a 15 d standard salt spray test, a few pinholes appeared on the surface of the deposit and the weight content of phosphorus on the surface of the deposit was higher (which was beneficial to the formation of the passivation films) than that before the standard salt spray test when the nickel content was lower because the dissolved weight of nickel was greater than that of phosphorus. The results from potentio-dynamic scan and EIS showed that passivation films formed on the Ni-P deposit after immersion in the NaC1 solutions, which decreased the corrosion rate of Ni-P samples. The results of this work show their potential applications in marine corrosion.

  9. Feasibility Study of Non-Destructive Techniques to Measure Corrosion in SAVY Containers

    Energy Technology Data Exchange (ETDEWEB)

    Davenport, Matthew Nicholas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-07-15

    Stainless Steel SAVY containers are used to transport and store nuclear material. They are prone to interior corrosion in the presence of certain chemicals and a low-oxygen environment. SAVY containers also have relatively thin walls to reduce their weight, making their structural integrity more vulnerable to the effects of corrosion. A nondestructive evaluation system that finds and monitors corrosion within containers in use would improve safety conditions and preclude hazards. Non-destructive testing can determine whether oxidation or corrosion is occurring inside the SAVY containers, and there are a variety of non-destructive testing methods that may be viable. The feasibility study described will objectively decide which method best fits the requirements of the facility and the problem. To improve efficiency, the containers cannot be opened during the non-destructive examination. The chosen technique should also be user-friendly and relatively quick to apply. It must also meet facility requirements regarding wireless technology and maintenance. A feasibility study is an objective search for a new technology or product to solve a particular problem. First, the design, technical, and facility feasibility requirements are chosen and ranked in order of importance. Then each technology considered is given a score based upon a standard ranking system. The technology with the highest total score is deemed the best fit for a certain application.

  10. THEORETICAL STUDY ON CORROSION INHIBITION PROPERTIES OF 2-ISOPROPYL-5-METHYLPHENOL

    Directory of Open Access Journals (Sweden)

    Saprizal Hadisaputra

    2016-08-01

    Full Text Available Corrosion inhibitors of 2-isopropyl-5-methylphenol and its derivatives has been elucidated by means of density functional theory at B3LYP/6-31G(d level of theory. Effect of electron donating and withdrawing groups such as NH2, SH, CHCH2, CH3, OH, CHO, COOH, F and NO2 on the corrosion inhibitor of 2-isopropyl-5-methylphenol derivatives also have been studied. The quantum chemical parameters such as the frontier orbital energies (EHOMO, ionization potential (I, electron affinity (A and electronegativity (χ are closely related to the corrosion inhibition efficiency (IE % of 2-isopropyl-5-methylphenol derivatives. The presence of electron donating groups increase IE % values meanwhile electron with drawing groups reduce IE % values. The enhancement of IE % follows NO2 < CHO < COOH < SH < F < CH3 < CHCH2 < OH < NH2. Electron donating NH2 group gives 96.38 % of IE %, pure 2-isopropyl-5-methylphenol IE % = 82.70 %. In contrast, electron withdrawing NO2 group gives IE % only 68.66 %. This theoretical study would have a significantly contribution for accelerating corrosion inhibitor experimental to gain optimum results.

  11. Density Functional Theory and Electrochemical Studies: Structure-Efficiency Relationship on Corrosion Inhibition.

    Science.gov (United States)

    Camacho-Mendoza, Rosa L; Gutiérrez-Moreno, Evelin; Guzmán-Percástegui, Edmundo; Aquino-Torres, Eliazar; Cruz-Borbolla, Julián; Rodríguez-Ávila, José A; Alvarado-Rodríguez, José G; Olvera-Neria, Oscar; Thangarasu, Pandiyan; Medina-Franco, José L

    2015-11-23

    The relationship between structure and corrosion inhibition of a series of 30 imidazol, benzimidazol, and pyridine derivatives has been established through the investigation of quantum descriptors calculated with PBE/6-311++G**. A quantitative structure-property relationship model was obtained by examination of these descriptors using a genetic functional approximation method based on a multiple linear regression analysis. Our results indicate that the efficiency of corrosion inhibitors is strongly associated with aromaticity, electron donor ability, and molecular volume descriptors. In order to calibrate and validate the proposed model, we performed electrochemical impedance spectroscopy (EIS) studies on imidazole, 2-methylimidazole, benzimidazole, 2-chloromethylbenzimidazole, pyridine, and 2-aminopyridine compounds. The experimental values for efficiency of corrosion inhibition are in good agreement with the estimated values obtained by our model, thus confirming that our approach represents a promising and suitable tool to predict the inhibition of corrosion attributes of nitrogen containing heterocyclic compounds. The adsorption behavior of imidazole or benzimidazole heterocyclic molecules on the Fe(110) surface was also studied to elucidate the inhibition mechanism; the aromaticity played an important role in the adsorbate-surface complex.

  12. Feasibility Study of Non-Destructive Techniques to Measure Corrosion in SAVY Containers

    Energy Technology Data Exchange (ETDEWEB)

    Davenport, Matthew Nicholas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-07-15

    Stainless Steel SAVY containers are used to transport and store nuclear material. They are prone to interior corrosion in the presence of certain chemicals and a low-oxygen environment. SAVY containers also have relatively thin walls to reduce their weight, making their structural integrity more vulnerable to the effects of corrosion. A nondestructive evaluation system that finds and monitors corrosion within containers in use would improve safety conditions and preclude hazards such as the ones shown in figures 1 and 2. Non-destructive testing can determine whether oxidation or corrosion is occurring inside the SAVY containers, and there are a variety of non-destructive testing methods that may be viable. The following feasibility study will objectively decide which method best fits the requirements of the facility and the problem. To improve efficiency, the containers cannot be opened during the non-destructive examination. The chosen technique should also be user-friendly and relatively quick to apply. It must also meet facility requirements regarding wireless technology and maintenance. A feasibility study is an objective search for a new technology or product to solve a particular problem. First, the design, technical, and facility feasibility requirements are chosen and ranked in order of importance. Then each technology considered is given a score based upon a standard ranking system. The technology with the highest total score is deemed the best fit for a certain application.

  13. Acoustic emission analysis coupled with thermogravimetric experiments dedicated to high temperature corrosion studies on metallic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Serris, Eric; Al Haj, Omar; Peres, Veronique; Cournil, Michel [Ecole Nationale Superieure des Mines de Saint-Etienne (France); Kittel, Jean; Grosjean, Francois; Ropital, Francois [IFP Energies nouvelles, BP3 rond-point de l' echangeur de Solaize (France)

    2014-11-01

    High temperature corrosion of metallic alloys (like iron, nickel, zirconium alloys) can damage equipment of many industrial fields (refinery, petrochemical, nuclear..). Acoustic emission (AE) is an interesting method owing to its sensitivity and its non-destructive aspect to quantify the level of damage in use of these alloys under various environmental conditions. High temperature corrosive phenomena create stresses in the materials; the relaxation by cracks of these stresses can be recorded and analyzed using the AE system. The goal of our study is to establish an acoustic signals database which assigns the acoustic signals to the specific corrosion phenomena. For this purpose, thermogravimetric analysis (TGA) is coupled with acoustic emission (AE) devices. The oxidation of a zirconium alloy, zircaloy-4, is first studied using thermogravimetric experiment coupled to acoustic emission analysis at 900 C. An inward zirconium oxide scale, preliminary dense, then porous, grow during the isothermal isobaric step. The kinetic rate increases significantly after a kinetic transition (breakaway). This acceleration occurs with an increase of acoustic emission activity. Most of the acoustic emission bursts are recorded after the kinetic transition. Acoustic emission signals are also observed during the cooling of the sample. AE numerical treatments (using wavelet transform) completed by SEM microscopy characterizations allows us to distinguish the different populations of cracks. Metal dusting represents also a severe form of corrosive degradation of metal alloy. Iron metal dusting corrosion is studied by AE coupled with TGA at 650 C under C{sub 4}H{sub 10} + H{sub 2} + He atmosphere. Acoustic emission signals are detected after a significant increase of the sample mass.

  14. Corrosion behavior of Mg/graphene composite in aqueous electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Selvam, M. [Centre for Nano Science and Technology, KS Rangasamy College of Technology, Tiruchengode, 637215, Tamil Nadu (India); Saminathan, K., E-mail: ksaminath@gmail.com [Centre for Nano Science and Technology, KS Rangasamy College of Technology, Tiruchengode, 637215, Tamil Nadu (India); Siva, P. [Centre for Nano Science and Technology, KS Rangasamy College of Technology, Tiruchengode, 637215, Tamil Nadu (India); Saha, P. [Department of Ceramic Engineering, National Institute of Technology, Rourkela, India-769008 (India); Rajendran, V. [Centre for Nano Science and Technology, KS Rangasamy College of Technology, Tiruchengode, 637215, Tamil Nadu (India)

    2016-04-01

    In the present work, the electrochemical corrosion behavior of magnesium (Mg) and thin layer graphene coated Mg (Mg/graphene) are studied in different salt electrolyte such as NaCl, KCl and Na{sub 2}SO{sub 4}. The phase structure, crystallinity, and surface morphology of the samples are investigated using X-ray diffraction (XRD) analysis, scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM/EDAX), and Raman spectroscopy techniques. The electrochemical corrosion behavior of the Mg and graphene coated Mg are also investigated using Electrochemical Impedance Spectroscopy (EIS) analysis. The tafel plot reveals that the corrosion of Mg drastically drops when coated with thin layer graphene (Mg/graphene) compared to Mg in KCl electrolyte. Moreover, the EIS confirms that Mg/graphene sample shows improve corrosion resistance and lower corrosion rate in KCl solution compare to all other electrolytes studied in the present system. - Highlights: • The corrosion behavior of magnesium alloy (AZ91) was investigated in three different electrolyte solution. • To study the anti-corrosion behavior of graphene coated with magnesium alloy. • To improve the corrosion resistance for magnesium alloy. • Nyquist plots confirms that MgG shows better corrosion resistance and lower corrosion rate in KCl solution.

  15. Corrosion Study of Stainless Steels in Peracetic Acid Bleach Media With and Without Chloride and Chelant

    Directory of Open Access Journals (Sweden)

    Rohtash

    2014-12-01

    Full Text Available The paper industries are adopting non-chlorine containing chemicals e.g. peroxide, ozone, peracids etc. as alternate of chlorine based bleach chemicals e.g. chlorine and chlorine dioxide etc. with the aim of eco-friend atmospheres. Changeover to the new chemicals in the bleaching process is likely to affect the metallurgy of the existing bleach plants due to change in the corrosivity of the media. Accordingly, corrosion investigations were performed in a peracid namely peracetic acid to test the suitability of austenitic stainless steels 654SMO, 265SMO, 2205, 317L and 316L. The performance of above stainless steels was evaluated through long term immersion tests and Electrochemical polarization measurements in peracetic acid (PAA bleach media at pH value 4 maintaining concentration 0.2 % as active oxygen along with three chloride levels 0, 500 and 1000 ppm in pulp-free laboratory. To study the effect of corrosion inhibitors with extending limit of chloride in liquors, measurements were also made with two types of chelants- EDTA & MgSO4. The results showed that corrosivity of PAA reduced by addition of chelant while increased with concentration of Cl¯. The results also exhibited that EDTA is better inhibitor than MgSO4.

  16. Atomistic Studies of Cation Transport in Tetragonal ZrO2 During Zirconium Corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Xian-Ming Bai; Yongfeng Zhang; Michael R. Tonks

    2013-10-01

    Zirconium alloys are the major fuel cladding materials in current reactors. The water-side corrosion is one of the major degradation mechanisms of these alloys. During corrosion the transport of oxidizing species in zirconium dioxide (ZrO2) determines the corrosion kinetics. Previously it has been argued that the outward diffusion of cation ions is important for forming protective oxides. In this work, the migration of Zr defects in tetragonal ZrO2 is studied with temperature accelerated dynamics and molecular dynamics simulations. The results show that Zr interstitials have anisotropic diffusion and migrate preferentially along the [001] or c direction in tetragonal ZrO2. The compressive stresses can increase the Zr interstitial migration barrier significantly. The migration barriers of some defect clusters can be much lower than those of point defects. The migration of Zr interstitials at some special grain boundaries is much slower than in a bulk oxide. The implications of these atomistic simulation results in the Zr corrosion are discussed.

  17. Study On The Effect Of Corrosion Behaviour Of Stainless Steel Before And After Carburizing Heat Treatment

    Science.gov (United States)

    Sulaiman, S. A.; Alias, S. K.; Ahmad, S.; Fauzi, M. H. Mohd; Ahmad, N. N.

    2016-11-01

    This study investigates the effect of corrosion behaviour of stainless steel before and after carburizing process. All samples were prepared based on the testing specification requirement and the chemical compositions of the stainless steel were obtained using spectrometer tester. Samples were then undergoing pack carburizing process by adding 50g of carbon powder as the carburizing agent. Then the samples were heated at 900 °C and 950 °C for 8 hours. To obtain corrosion rate, weight loss test was conducted and the samples were immersed in three different solutions which were distilled water, hydrochloric acid and sodium chloride. Hardness and density test were employed to measure the physical properties of the ASTM 304 stainless steel. The microstructures of all samples were observed using Olympus BX41M optical microscope. The resulting phases after each heat treatment were tested by x-ray diffraction (XRD) tester. The percentage of corrosion values, determined from this technique, showed fairly good agreement. Carburizing process produced a carburizing layer improved mechanical properties and corrosion resistance abilities

  18. Study of Microbiologically Induced Corrosion Action on Al-6Mg-Zr and Al-6Mg-Zr-Sc

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The corrosion behaviors of Al-6Mg-Zr and Al-6Mg-Zr-Sc in the sulfate-reducing bacteria (SRB) solution in anaerobic environment were studied using electrochemical, microbiological, and surface analysis methods. It was found that the oxide film was more compact owing to the addition of Sc resulting in the open circuit potential shifting by about 100mV positively. On the other hand, it was seen that the pitting sensitivity of Al-6Mg-Zr-Sc alloy in SRB solution decreased and its microbiologically influenced corrosion resistance was improved. Pitting corrosion occurring on the surface of the two alloys under the comprehensive action of the metabolism of SRB was observed by SEM. It was obtained by EDS that the corrosion degree increased with time and corrosion was furthered by deposition of the product.

  19. A study of steel bar reinforcement corrosion in concretes with SF and SRH using electrochemical impedance spectroscopy

    Directory of Open Access Journals (Sweden)

    Fernanda Giannotti da Silva

    2006-06-01

    Full Text Available Several electrochemical techniques can be used to monitor corrosion, among them are open circuit potential (OCP and eletrochemical impedance spectroscopy (EIS. Monitoring OCP is the most typical procedure for routine inspection of reinforced concrete structures and can be easily carried out, however it only gives an approximate idea of the corrosion process. EIS is a more complete technique, which supplies information regarding the mechanism and kinetics of reaction electrochemistries, but only used in the laboratory. Based on these two techniques, this study is related to the steel corrosion in high-performance concrete with silica fume and silica from rice husk. The acceleration of the corrosion was carried out using immersion cycles in a 3.5% NaCl solution. As well as high compressive strength values, the addition of silica fume presented low corrosion risks and high impedance module values and significant increases of the concrete resistivity after 22 months of alternate immersion/drying cycles were obtained.

  20. Study of caffeine as corrosion inhibitors of carbon steel in chloride solution containing hydrogen sulfide using electrochemical impedance spectroscopy (EIS)

    Science.gov (United States)

    Solehudin, Agus; Berman, Ega Taqwali; Nurdin, Isdiriayani

    2015-09-01

    The corrosion behaviour of steel surface in the absence and presence of caffeine in 3.5% NaCl solution containing dissolved H2S gas is studied using electrochemical impedance spectroscopy (EIS). The experimental results of carbon steel corrosion in 3.5% NaCl solution containing 500 mg/l H2S at different caffeine concentrations showed that corrosion rate of carbon steel decreases with increasing of caffeine concentrations from 0 to 0,1 mmol/l. Whereas, the corrosion rate increase with increasing of caffeine concentrations from 1 to 10 mmol/l. It is clear that no inhibition efficiency increases with increasing inhibitor concentration. The optimum value of inhibition efficiency was 90% at a caffeine concentration of 0.1 mmol/l. This suggests that caffeine's performance as a corrosion inhibitor is more effective at a concentration of 0.1 mmol/l.

  1. A galvanic corrosion study of brass/stainless steel and brass/cast iron couples; Estudio de corrosion galvanica en pares laton/acero inoxidable y laton/fundicion de hierro

    Energy Technology Data Exchange (ETDEWEB)

    Ohanian, M.; Diaz, V.; Corengia, M.; Zinola, C. F.

    2011-07-01

    Corrosion attack in heat exchanger systems is a topic of main interest for the maintenance in each industrial plant. These are multi galvanic systems with particular geometric and fluidodynamic complexity. Corrosive damages include zinc selective dealeation in copper alloys. In order to explain zinc dealeation attack, this paper deals with laboratory scale testing, characterization and interactions between two copper and zinc alloys (Yellow brass UNS C268 and Admiralty brass UNS C443) compared to AISI 316 stainless steel and cast iron. The tests were performed at 20 degree centigrade in 1.5 % NaCl and 1.5 % Na{sub 2}SO{sub 4} solutions, pH 8 and each material was characterized by potentiodynamic sweeps. The couples are analyzed by studying transient galvanic currents. We conclude about the cause of the analyzed pathology, brass protection potential ranges and its coupling compatibility with other metals. (Author) 33 refs.

  2. [Experimental study on the corrosion behavior of a type of oral near β-type titanium alloys modified with double glow plasma nitriding].

    Science.gov (United States)

    Wen, Ke; Li, Fenglan

    2015-12-01

    To study the electrochemical corrosion performance of a type of biomedical materials near beta titanium alloy(Ti-3Zr-2Sn-3Mo-25Nb, TLM) in artificial saliva before and after nitride changing, and to provide clinical basis for clinical application of titanium alloy TLM. The double glow plasma alloying technology was used to nitride the surface of titanium alloy TLM. The surface properties of the modified layer were observed and tested by optical microscope, scanning electron microscope, glow discharge spectrum analyzer, X-ray diffraction and micro hardness tester. Then, electrochemical measurement system was used to test and compare titanium alloy TLM's electrochemical corrosion in artificial saliva before and after its surface change. Finally, the surface morphology of the original titanium alloy and the modified layer was compared by scanning electron microscope. By the technology of double glow plasma nitriding, the surface of the titanium alloy TLM had been successfully nitrided with a modified layer of 4-5 µm in thickness, uniform and compact. Its main compositions were Ti and Ti(2)N. The Microhardness of modified layer also had been improved from (236.8 ± 5.4) to (871.8 ± 5.2) HV. The self-corrosion potential in electrochemical corrosion tests had been increased from -0.559 V to -0.540 V, while the self- corrosion current density had been reduced from 2.091 × 10(-7) A/cm(2) to 7.188 × 10(-8) A/cm(2). Besides, alternating-current impedance(AC Impedance) had also been increased. With the scanning electron microscope, it's obvious that the diameter of corrosion holes on modified layer were approximately 10 µm. As to the diameter and number of corrosion holes on modified layer, they had been decreased comparing with the original titanium alloy. The type of near beta titanium alloy TLM can construct a nitriding modified layer on its surface. Meanwhile, the performance of its anti- corrosion in artificial saliva has been improved, comparing to the original

  3. Formation of Chromium Coating and Comparative Examination on Corrosion Resistance with 13Cr Steel in CO2-SATURATED Simulated Oilfield Brine

    Science.gov (United States)

    Zou, Jiaojuan; Xie, Faqin; Lin, Naiming; Yao, Xiaofei; Tian, Wei; Tang, Bin

    2013-07-01

    In order to enhance the surface properties of P110 oil casing tube steel and increase its usage during operation, chromium coating was fabricated by pack cementation. Scanning electron microscope, energy dispersive spectrometry and X-ray diffraction were used to investigate the surface morphology, cross-sectional microstructure, element distribution and phase constitutions of the coating. Comparative examinations on corrosion resistance between chromium coating and 13Cr stainless steel in CO2-saturated simulated oilfield brine were carried out via electrochemical measurements. The results showed that the obtained coating was uniform and compact, mainly consisted of CrxCy and doped with minor Cr2N. Chromizing treatment made it possible to create on the working surface of P110 steel with enhanced corrosion resistance, and the chromium coating indicated lower pitting corrosion sensitivity than that of 13Cr stainless steel.

  4. Comparative High-Temperature Corrosion Behavior of Ni-20Cr Coatings on T22 Boiler Steel Produced by HVOF, D-Gun, and Cold Spraying

    Science.gov (United States)

    Kaushal, Gagandeep; Bala, Niraj; Kaur, Narinder; Singh, Harpreet; Prakash, Satya

    2014-01-01

    To protect materials from surface degradations such as wear, corrosion, and thermal flux, a wide variety of materials can be deposited on the materials by several spraying processes. This paper examines and compares the microstructure and high-temperature corrosion of Ni-20Cr coatings deposited on T22 boiler steel by high velocity oxy-fuel (HVOF), detonation gun spray, and cold spraying techniques. The coatings' microstructural features were characterized by means of XRD and FE-SEM/EDS analyses. Based upon the results of mass gain, XRD, and FE-SEM/EDS analyses it may be concluded that the Ni-20Cr coating sprayed by all the three techniques was effective in reducing the corrosion rate of the steel. Among the three coatings, D-gun spray coating proved to be better than HVOF-spray and cold-spray coatings.

  5. Corrosion of metals in wood : comparing the results of a rapid test method with long-term exposure tests across six wood treatments

    Science.gov (United States)

    Samuel L. Zelinka; Donald S. Stone

    2011-01-01

    This paper compares two methods of measuring the corrosion of steel and galvanized steel in wood: a long-term exposure test in solid wood and a rapid test method where fasteners are electrochemically polarized in extracts of wood treated with six different treatments. For traditional wood preservatives, the electrochemical extract method correlates with solid wood...

  6. 盐渍强腐蚀地区耐腐蚀混凝土试验研究%STUDIES OF CONCRETE'S CORROSION RESISTANCE IN SALTY CORROSION AREA

    Institute of Scientific and Technical Information of China (English)

    张玲玲; 倪娜; 张陵; 张靖

    2015-01-01

    我国西北地区许多工程所在地地下水及地基土具有强腐蚀性,同时因气候原因,全年温差较大,这些客观条件都对混凝土的耐腐蚀性能提出较高的要求。通过一系列的耐腐蚀性能试验,研究了5种配方的混凝土耐腐蚀性能。结果表明:采用高抗硫酸盐水泥加阻锈剂配置的C25混凝土的耐腐蚀性能较差,而采用P· O 42.5水泥加矿物掺料配置的C30、C40混凝土的耐腐蚀性能较好。%In Northwest, groundwater and subsoil of many projects are highly corrosive, moreover, the annual temperature is largely different due to the climate.So the higher requirements are put forward to the corrosion resistance of concrete.A series of corrosion resistance experiments were made to study the corrosion resistance of five kinds of concretes.The results indicated that the corrosion resistance of concrete C30 and C40 with ordinary Portland cement P· O 42.5 and mineral admixtures was better than that of concrete C25 with high sulfate cement and rust inhibitor.

  7. A study on species transport in the corrosion products of ferrous archaeological analogues - a contribution to the modelling of iron long term corrosion behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Vega, E.; Dillmann, Ph.; Fluzin, Ph. [LRC CEA DSM 01-27: IRAMAT UMR5060 CNRS et Laboratoire Pierre Sue (CEA/CNRS), CEA Saclay 91191 Gif-sur-Yvette Cedex (France)

    2004-07-01

    One of the main technological and environmental challenges for the next centuries is the safe storage of nuclear wastes. For this purpose, the behaviour during several centuries of every material constituting the barrier between wastes and environment must be predicted. In addition to modelling and laboratory simulations, the only mean to study corrosion systems formed during several centuries is to analyse archaeological ferrous artefacts buried in soil. Precedent studies on this kind of artefacts have shown that the corrosion system is formed by the metallic core, a dense corrosion product layer, a transformed medium constituted of a mix of corrosion products and soil compounds, and the soil itself. Moreover, analytical and electrochemical studies seem to show that the corrosion mechanisms are driven by the species transport in the dense product layer (DPL) and especially by oxygen migration in the DPL pores. Thus, it seems necessary to precise the species transport properties in the DPL. A characterisation study on ferrous artefacts coming from the site of Glinet (16. AD) have been carried out. The rust layers have been studied using several techniques. The composition analyses were performed with Energy Dispersive Spectroscopy (EDS) coupled to the Scanning Electron Microscope, and Electron Probe Microanalysis (EPMA). Structural information have been obtained by X-ray micro-diffraction ({mu}XRD) and micro-Raman spectroscopy. The aim of this communication is to present the results of a study performed with markers in order to better understand the species transport in the DPL. Experiments focus on an archaeological artefact part from Glinet excavation. The migration in the DPL of I and Na ions (which have roughly the same diffusion coefficient in water than oxygen) will be studied by immersion of an archaeological analogue with his DPL in a saturated iodide (NaI) aqueous solution. After different immersion times (1 h, 3 h, 7 h and 168 h), the concentration

  8. Plant applications of online corrosion monitoring: CO2 capture amine plant case study

    NARCIS (Netherlands)

    Kane, R.D.; Srinivasan, S.; Khakharia, P.M.; Goetheer, E.L.V.; Mertens, J.; Vroey, S. de

    2015-01-01

    Over the past several years, there has been a significant effort to bring corrosion monitoring into the realm of online, real-time management with plant process control technology. As part of this new direction in corrosion monitoring, corrosion data (e.g. information on corrosion rate, measured Ste

  9. Plant applications of online corrosion monitoring: CO2 capture amine plant case study

    NARCIS (Netherlands)

    Kane, R.D.; Srinivasan, S.; Khakharia, P.M.; Goetheer, E.L.V.; Mertens, J.; Vroey, S. de

    2015-01-01

    Over the past several years, there has been a significant effort to bring corrosion monitoring into the realm of online, real-time management with plant process control technology. As part of this new direction in corrosion monitoring, corrosion data (e.g. information on corrosion rate, measured

  10. Study of the HVOF Ni-Based Coatings' Corrosion Resistance Applied on Municipal Solid-Waste Incinerators

    Science.gov (United States)

    Guilemany, J. M.; Torrell, M.; Miguel, J. R.

    2008-06-01

    Oxidation of exchanger steel tubes causes important problems in Municipal Solid-Waste Incinerator (MSWI) plants. The present paper shows a possible solution for this problem through High-Velocity Oxygen Fuel (HVOF) thermal spray coatings. A comparative study was carried out between powder and wire Ni-based thermal spray coatings (with the same composition). These optimized coatings were compared based on their microstructure, wear properties (ASTM G99-90, ASTM G65-91), and erosion-corrosion (E-C) resistance. An E-C test designed in the Thermal Spray Centre was performed to reproduce the mechanisms that take place in a boiler. Studying the results of this test, the wire HVT Inconel coating sprayed by propylene appears to be the best alternative. A commercial bulk material with a composition similar to Ni-based coatings was tested to find the products of the oxidation reactions. The protective mechanisms of these materials were assessed after studying the results obtained for HVOF coatings and the bulk material where the presence of nickel and chromium oxides as a corrosion product can be seen. Kinetic evolution of the Ni-based coatings can be studied by thermogravimetric analysis. The protection that Inconel coatings give to the tube through the difference of the gain mass can be seen. Ni-based HVOF coatings by both spray conditions are a promising alternative to MSWI protection against chlorine environments, and their structures have a very important role.

  11. Physicochemical studies of glucose, gellan gum, and hydroxypropyl cellulose--inhibition of cast iron corrosion.

    Science.gov (United States)

    Rajeswari, Velayutham; Kesavan, Devarayan; Gopiraman, Mayakrishnan; Viswanathamurthi, Periasamy

    2013-06-05

    Glucose, gellan gum, and hydroxypropyl cellulose were studied against the acid corrosion of cast iron by means of weight loss, potentiodynamic polarization, and AC impedance spectroscopy techniques. The inhibition efficiency was found to increase with increasing concentration of the inhibitors. The effect of immersion time and temperature were also studied. The addition of potassium iodide to the corrosion-inhibition system showed both antagonism and synergism toward inhibition efficiency. Polarization studies revealed the mixed-type inhibiting nature of the carbohydrates. The adsorption of inhibitors on the cast iron surface obeys Langmuir adsorption isotherm model, both in presence and absence of KI. Physical interaction between the inhibitor molecules and the iron surface was suggested by the thermochemical parameters, rather than chemical interaction.

  12. Lithium-system corrosion/erosion studies for the FMIT project

    Energy Technology Data Exchange (ETDEWEB)

    Bazinet, G D [comp.

    1983-04-01

    The corrosion behavior of selected materials in a liquid lithium environment has been studied in support of system and component designs for the Fusion Materials Irradiation Test (FMIT) Facility. The liquid lithium test resources and the capabilities of several laboratories were used to study specific concerns associated with the overall objective. Testing conditions ranged from approx. 3700 hours to approx. 6500 hours of exposure to flowing lithium at temperatures from 230/sup 0/C to 270/sup 0/C and static lithium at temperatures from 200/sup 0/C to 500/sup 0/C. Principal areas of investigation included lithium corrosion/erosion effects of FMIT lithium system materials (largely Type 304 and Type 304L austenitic stainless steels) and candidate materials for major system components.

  13. Electrochemical Study on Newly Synthesized Chlorocurcumin as an Inhibitor for Mild Steel Corrosion in Hydrochloric Acid

    Directory of Open Access Journals (Sweden)

    Ahmed A. Al-Amiery

    2013-11-01

    Full Text Available A new curcumin derivative, i.e., (1E,4Z,6E-5-chloro-1,7-bis(4-hydroxy-3-methoxyphenylhepta-1,4,6-trien-3-one (chlorocurcumin, was prepared starting with the natural compound curcumin. The newly synthesized compound was characterized by elemental analysis and spectral studies (IR, 1H-NMR and 13C-NMR. The corrosion inhibition of mild steel in 1 M HCl by chlorocurcumin has been studied using potentiodynamic polarization (PDP measurements and electrochemical impedance spectroscopy (EIS. The inhibition efficiency increases with the concentration of the inhibitor but decreases with increases in temperature. The potentiodynamic polarization reveals that chlorocurcumin is a mixed-type inhibitor. The kinetic parameters for mild steel corrosion were determined and discussed.

  14. SERS and DFT study of copper surfaces coated with corrosion inhibitor

    Directory of Open Access Journals (Sweden)

    Maurizio Muniz-Miranda

    2014-12-01

    Full Text Available Azole derivatives are common inhibitors of copper corrosion due to the chemical adsorption occurring on the metal surface that gives rise to a protective film. In particular, 1,2,4-triazole performs comparable to benzotriazole, which is much more widely used, but is by no means an environmentally friendly agent. In this study, we have analyzed the adsorption of 1,2,4-triazole on copper by taking advantage of the surface-enhanced Raman scattering (SERS effect, which highlights the vibrational features of organic ligand monolayers adhering to rough surfaces of some metals such as gold, silver and copper. To ensure the necessary SERS activation, a roughening procedure was implemented on the copper substrates, resulting in nanoscale surface structures, as evidenced by microscopic investigation. To obtain sufficient information on the molecule–metal interaction and the formation of an anticorrosive thin film, the SERS spectra were interpreted with the aid of theoretical calculations based on the density functional theory (DFT approach.

  15. Study on Localized Corrosion Cracking of Alloy 600 using EN-DCPD Technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yeonju; Kim, Sungwoo; Kim, Hongpyo; Hwang, Seongsik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-02-15

    The object of this work is to establish an electrochemical noise(EN) measurement technique combined with a direct current potential drop(DCPD) method for monitoring of localized corrosion cracking of nickel-based alloy, and to analyze its mechanism. The electrochemical current and potential noises were measured under various conditions of applied stress to a compact tension specimen in a simulated primary water chemistry of a pressurized water reactor. The amplitude and frequency of the EN signals were evaluated in both time and frequency domains based on a shot noise theory, and then quantitatively analyzed using statistical Weibull distribution function. From the spectral analysis, the effect of the current application in DCPD was found to be effectively excluded from the EN signals generated from the localized corrosion cracking. With the aid of a microstructural analysis, the relationship between EN signals and the localized corrosion cracking mechanism was investigated by comparing the shape parameter of Weibull distribution of a mean time-to-failure.

  16. Corrosion behaviour of galvanized steel and electroplating steel in aqueous solution: AC impedance study and XPS

    Energy Technology Data Exchange (ETDEWEB)

    Lebrini, M.; Fontaine, G. [Laboratoire des Procedes d' Elaboration des Revetements Fonctionnels, LSPES UMR CNRS 8008, ENSCL, BP 90108, F-59652 Villeneuve d' Ascq Cedex (France); Gengembre, L. [Unite de Catalyse et Chimie du solide UMR 8181 Bat C3, USTL, F-59655 Villeneuve d' Ascq Cedex (France); Traisnel, M. [Laboratoire des Procedes d' Elaboration des Revetements Fonctionnels, LSPES UMR CNRS 8008, ENSCL, BP 90108, F-59652 Villeneuve d' Ascq Cedex (France)], E-mail: Michel.Traisnel@ensc-lille.fr; Lerasle, O.; Genet, N. [TOTAL France, Centre de Recherche de Solaize, Chemin du canal, BP 22, F-69360 Solaize (France)

    2008-08-30

    The efficiency of a new triazole derivative, namely, 2-{l_brace}(2-hydroxyethyl)[(4-methyl-1H-1,2,3-benzotriazol-1-yl)methyl]amino{r_brace} ethanol (TTA) has been studied for corrosion inhibition of galvanized steel and electroplating steel in aqueous solution. Corrosion inhibition was studied using electrochemical impedance spectroscopy (EIS). These studies have shown that TTA was a very good inhibitor. Data obtained from EIS show a frequency distribution and therefore a modelling element with frequency dispersion behaviour, a constant phase element (CPE) has been used. The corrosion behaviour of galvanized steel and electroplating steel in aqueous solution was also investigated in the presence of 4-methyl-1H-benzotriazole (TTA unsubstituted) by EIS. These studies have shown that the ability of the molecule to adsorb on the steel surface was dependent on the group in triazole ring substituent. X-ray photoelectron spectroscopy surface analysis with TTA shows that it chemisorbed on surface of galvanized steel and electroplating steel.

  17. An experimental study on cavitation erosion-corrosion performance of ANSI 1020 and ANSI 4135 steel

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Leqin; Qiu, Ning [Institute of Process Equipment, Zhejiang University, Hangzhou (China); Hellmann, Dieter-Heinz [KSB Aktiengesellschaft, Frankenthal (Germany); Zhu, Xiaowen [Zhejiang Keer Pump Stock Co., Ltd, Whenzhou (China)

    2016-02-15

    Cavitation erosion is quite complex, containing corrosion-erosion interaction effect. High temperature oxidization may be aroused after bubble collapse, accompanied by hot gas contacting with the pump component surface. The analysis of the erosion pits can be an effective way to know the mechanism of cavitation erosion. In present paper, the cavitation erosion resistance of carbon steel (ANSI 1020) and alloy steel (ANSI 4135) were tested in an ultrasonic vibration apparatus. By using energy dispersive X-ray spectroscope and three dimensional laser microscope, the chemical composition around erosion pits and the oxidation film structure were analyzed. By using metallographic microscope and scanning electronic microscope, the metallographic structure of specimens (e.g., carbon steel and alloy steel), the nano structured iron oxide and corresponding influence on specimen's anti-erosion performance were discussed. Based on the comparison between the different tests performed in distilled water and tap water respectively, results can be obtained that erosion rate of carbon steel and alloy steel varies with the component of water which had close correlation to the oxidation effect. Erosion rate of alloy steel 4135 was much lower in distilled water compared to tap water while the difference of carbon steel 1020 was not that large. The remarkable different responses of these two materials had close relationship with oxidation effect. The oxidation effect transferred the original structure of alloy steel surface which had high anti-erosion capability, into newly generated iron oxide structure, which was preferentially to be attacked. The pumping of slightly corrosive fluids frequently leads to erosion-corrosion damage on impellers, and corrosion can further amplify the erosion process.

  18. Study of the Effect of Swelling on Irradiation Assisted Stress Corrosion Cracking

    Energy Technology Data Exchange (ETDEWEB)

    Teysseyre, Sebastien Paul [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    This report describes the methodology used to study the effect of swelling on the crack growth rate of an irradiation-assisted stress corrosion crack that is propagating in highly irradiated stainless steel 304 material irradiated to 33 dpa in the Experimental Breeder Reactor-II. The material selection, specimens design, experimental apparatus and processes are described. The results of the current test are presented.

  19. Oral factors affecting titanium elution and corrosion: an in vitro study using simulated body fluid.

    Directory of Open Access Journals (Sweden)

    Hideki Suito

    Full Text Available OBJECTIVES: Ti, which is biocompatible and resistant to corrosion, is widely used for dental implants, particularly in patients allergic to other materials. However, numerous studies have reported on Ti allergy and the in vitro corrosion of Ti. This study investigated the conditions that promote the elution of Ti ions from Ti implants. METHODS: Specimens of commercially pure Ti, pure nickel, a magnetic alloy, and a gold alloy were tested. Each specimen was immersed in a simulated body fluid (SBF whose pH value was controlled (2.0, 3.0, 5.0, 7.4, and 9.0 using either hydrochloric or lactic acid. The parameters investigated were the following: duration of immersion, pH of the SBF, contact with a dissimilar metal, and mechanical stimulus. The amounts of Ti ions eluted were measured using a polarized Zeeman atomic absorption spectrophotometer. RESULTS: Eluted Ti ions were detected after 24 h (pH of 2.0 and 3.0 and after 48 h (pH of 9.0. However, even after 4 weeks, eluted Ti ions were not detected in SBF solutions with pH values of 5.0 and 7.4. Ti elution was affected by immersion time, pH, acid type, mechanical stimulus, and contact with a dissimilar metal. Elution of Ti ions in a Candida albicans culture medium was observed after 72 h. SIGNIFICANCE: Elution of Ti ions in the SBF was influenced by its pH and by crevice corrosion. The results of this study elucidate the conditions that lead to the elution of Ti ions in humans, which results in implant corrosion and Ti allergy.

  20. Novel electrochemical approach to study corrosion mechanism of Al-Au wire-bond pad interconnections

    DEFF Research Database (Denmark)

    Elisseeva, O. V.; Bruhn, A.; Cerezo, J.;

    2013-01-01

    A gold-aluminium material combination is typically employed as an interconnection for microelectronic devices. One of the reliability risks of such devices is that of corrosion of aluminium bond pads resulting from the galvanic coupling between an aluminium bond pad and a gold wire. The research...... presented in this manuscript focuses on studying bond pad corrosion by selecting an appropriate model system and a dedicated set of electrochemical and analytical experimental tools. Taking into account the complex three-dimensional structure and the small dimensions of Au-Al interconnections (around 50...... gold films were applied on Ti-Al covered silicon surfaces, and their morphology and electrochemical behaviour were analysed using the localised electrochemical cell, scanning vibrating electrode technique, scanning electron microscopy-energy dispersive X-ray spectroscopy, scanning electron microscopy...

  1. Study on Marine Corrosion and Antifouling Behavior of Copper Alloys Exposed to Sea Areas in China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The relationship of corrosion resistance and antifouling behavior of 19 Cu alloys exposed to seawater of Qingdao ,Xiamen,Yulin sea areas in China for 1,2,4,8 year intervals was studied .The experiments were carried on by analyzing the composition of corrosion films formed on the surface of alloy specimens during the immersion time and by using OM,SEM,EDXA and AES experiment methods.The results verify the view point that it is the cuprous oxide film which played an important role in antifouling property of Cu alloys in seawater and throw a light on the view point in details further.The influence of different sea areas on the antifouling property of Cu alloys is also discussed.

  2. Semiempirical Theoretical Studies of 1,3-Benzodioxole Derivatives as Corrosion Inhibitors

    Directory of Open Access Journals (Sweden)

    Omnia A. A. El-Shamy

    2017-01-01

    Full Text Available The efficiency of 1,3-benzodioxole derivatives as corrosion inhibitors is theoretically studied using quantum chemical calculation and Quantitative Structure Activity Relationship (QSAR. Different semiempirical methods (AM1, PM3, MNDO, MINDO/3, and INDO are applied in order to determine the relationship between molecular structure and their corrosion protection efficiencies. Different quantum parameters are obtained as the energy of highest occupied molecular orbital EHOMO, the energy of the lowest unoccupied molecular orbital ELUMO, energy gap ΔEg, dipole moment μ, and Mulliken charge on the atom. QSAR approach is applied to elucidate some important parameters as the hydrophobicity (Log P, surface area (S.A, polarization (P, and hydration energy (EHyd.

  3. A study on corrosion resistant graphene films on low alloy steel

    Directory of Open Access Journals (Sweden)

    A. S. Sai Pavan

    2016-04-01

    Full Text Available Abstract Graphene nanosheets were produced after synthesizing graphene oxide via Hummer’s method and a modified Hummer’s method. The obtained graphene after reduction was dispersed in 1-propanol to get a coating solution. Mild steel coupons were coated with the graphene solution via dip coating method. Corrosion studies were carried out at different environments like water (pH 6.0, HCl (0.1 N, NaCl (3.5 wt% and NaOH (1 M. Tafel analysis showed a reduction in the corrosion rate up to 99 % after three layer deposition with the graphene developed using the modified Hummer’s method. X-ray diffraction and Raman Spectroscopy confirmed the presence of graphene.

  4. A study on corrosion resistant graphene films on low alloy steel

    Science.gov (United States)

    Sai Pavan, A. S.; Ramanan, Sutapa Roy

    2016-11-01

    Graphene nanosheets were produced after synthesizing graphene oxide via Hummer's method and a modified Hummer's method. The obtained graphene after reduction was dispersed in 1-propanol to get a coating solution. Mild steel coupons were coated with the graphene solution via dip coating method. Corrosion studies were carried out at different environments like water (pH 6.0), HCl (0.1 N), NaCl (3.5 wt%) and NaOH (1 M). Tafel analysis showed a reduction in the corrosion rate up to 99 % after three layer deposition with the graphene developed using the modified Hummer's method. X-ray diffraction and Raman Spectroscopy confirmed the presence of graphene.

  5. Erosion-corrosion; Erosionkorrosion

    Energy Technology Data Exchange (ETDEWEB)

    Aghili, B

    1999-05-01

    A literature study on erosion-corrosion of pipings in the nuclear industry was performed. Occurred incidents are reviewed, and the mechanism driving the erosion-corrosion is described. Factors that influence the effect in negative or positive direction are treated, as well as programs for control and inspection. Finally, examples of failures from databases on erosion-corrosion are given in an attachment 32 refs, 16 figs, tabs

  6. Study of pitting corrosion in line-pipe steel under the influence of remanent magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Espina-Hernandez, J.H.; Caleyo, F.; Hallen, J.M. [Instituto Politecnico Nacional (IPN), Zacatenco (Mexico)

    2009-07-01

    The influence of remanent magnetization on pitting corrosion in line-pipe steels is studied. Pitting corrosion experiments have been carried out on samples of an API 5L grade 52 steel under a magnetization level of the same order of magnitude of the remanent magnetization in the pipeline wall after in-line inspection based on magnetic flux leakage. The samples were magnetized using rings of the same grade as the investigated steel. Immediately after magnetization, the investigated samples were subjected to pitting by immersing them in a solution containing dissolved Cl{sup -} and SO{sup 2-}{sub 4} and ions. The pitting experiments were conducted during a seven days period. The pit depth distribution and the maximum pit depth in each sample were recorded and used to conduct extreme value analyses of the pitting process in magnetized and non-magnetized control samples. The statistical assessment of the pitting corrosion data collected during this study shows that the magnetic field reduces the average depth of the pit population and also the extreme pit depth values that can be predicted from the maximum values observed in the magnetized samples in comparison with to the non-magnetized control samples. Scanning electron microscopy observations show that the magnetic field alters the pit morphology by increasing the pit mouth opening. (author)

  7. Study of pitting corrosion in line-pipe steel under the influence of remanent magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Espina-Hernandez, J.H.; Caleyo, F.; Hallen, J.M. [Instituto Politecnico Nacional (IPN), Zacatenco (Mexico)

    2009-07-01

    The influence of remanent magnetization on pitting corrosion in line-pipe steels is studied. Pitting corrosion experiments have been carried out on samples of an API 5L grade 52 steel under a magnetization level of the same order of magnitude of the remanent magnetization in the pipeline wall after in-line inspection based on magnetic flux leakage. The samples were magnetized using rings of the same grade as the investigated steel. Immediately after magnetization, the investigated samples were subjected to pitting by immersing them in a solution containing dissolved Cl{sup -} and SO{sup 2-}{sub 4} and ions. The pitting experiments were conducted during a seven days period. The pit depth distribution and the maximum pit depth in each sample were recorded and used to conduct extreme value analyses of the pitting process in magnetized and non-magnetized control samples. The statistical assessment of the pitting corrosion data collected during this study shows that the magnetic field reduces the average depth of the pit population and also the extreme pit depth values that can be predicted from the maximum values observed in the magnetized samples in comparison with to the non-magnetized control samples. Scanning electron microscopy observations show that the magnetic field alters the pit morphology by increasing the pit mouth opening. (author)

  8. Corrosion behavior of Ti–39Nb alloy for dentistry

    Energy Technology Data Exchange (ETDEWEB)

    Fojt, Jaroslav, E-mail: fojtj@vscht.cz [Institute of Chemical Technology, Technicka 5, 166 28 Prague (Czech Republic); Joska, Ludek [Institute of Chemical Technology, Technicka 5, 166 28 Prague (Czech Republic); Malek, Jaroslav [UJP Praha, Nad Kamínkou 1345, 156 10 Prague-Zbraslav (Czech Republic); Sefl, Vaclav [Institute of Chemical Technology, Technicka 5, 166 28 Prague (Czech Republic)

    2015-11-01

    To increase an orthopedic implant's lifetime, researchers are now concerned on the development of new titanium alloys with suitable mechanical properties (low elastic modulus–high fatigue strength), corrosion resistance and good workability. Corrosion resistance of the newly developed titanium alloys should be comparable with that of pure titanium. The effect of medical preparations containing fluoride ions represents a specific problem related to the use of titanium based materials in dentistry. The aim of this study was to determine the corrosion behavior of β titanium alloy Ti–39Nb in physiological saline solution and in physiological solution containing fluoride ions. Corrosion behavior was studied using standard electrochemical techniques and X-ray photoelectron spectroscopy. It was found that corrosion properties of the studied alloy were comparable with the properties of titanium grade 2. The passive layer was based on the oxides of titanium and niobium in several oxidation states. Alloying with niobium, which was the important part of the alloy passive layer, resulted in no significant changes of corrosion behavior. In the presence of fluoride ions, the corrosion resistance was higher than the resistance of titanium. - Highlights: • Alloy Ti–39Nb shows excellent corrosion resistance in physiological solution. • Corrosion resistance of Ti–39Nb alloy is significantly higher than that of titanium in the presence of fluoride ions. • The electrochemical impedance spectroscopy indicates a porous passive layer. • Passive layer of the alloy is enriched by niobium.

  9. Measurement of electrochemical noise for the study of corrosion processes of metallic alloys; Medida de ruido electroquimico para el estudio de rocesoso de corrosion de aleaciones metalicas

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Amaya, J. M.; Bethencourt, M.; Gonzalez-Rovira, L.; Botana, F. J.

    2009-07-01

    Electrochemical noise (EN) is a technique that allows the estimation of both the rate and the corrosion mechanism of different metallic alloys by means of the measurement and the analysis of the fluctuations of current and voltage. Its main advantage against other electrochemical techniques is that during the measurement process, the corrosive systems under study are not instrumentally disturbed, and therefore, the systems are kept at their natural corrosion potential. Two steps are necessary to use this technique: measurement and analysis of the EN signals. In this paper, the most important concepts related only to the measurement of EN are revised. The parameters most employed in the literature to analyse the EN signals will be described in another paper. In the present article, the experimental devices normally used to measure EN signals are firstly analysed. Subsequently, the most important properties of the EN signals are studied. Finally, the external sources of instrumental noise that can affect to the EN signals are described. (Author) 65 refs.

  10. Corrosion in Haas expanders with and without use of an antimicrobial agent: an in situ study

    Directory of Open Access Journals (Sweden)

    Cristhiane Ristum Bagatin

    2011-12-01

    Full Text Available OBJECTIVES: The purpose of this study was to evaluate in situ the occurrence of corrosion in the soldering point areas between the wire, silver brazing and band in Haas expanders. MATERIAL AND METHODS: Thirty-four 7-12-year-old patients who needed maxillary expansion with a Haas expander were randomly assigned to two groups of 17 individuals each, according to the oral hygiene protocol adopted during the orthodontic treatment: Group I (control, toothbrushing with a fluoride dentifrice and Group II (experimental, toothbrushing with the same dentifrice plus 0.12% chlorhexidine gluconate (Periogard® mouthrinses twice a week. The appliances were removed after approximately 4 months. Fragments of the appliances containing a metallic band with a soldered wire were sectioned at random for examination by stereomicroscopy, scanning electron microscopy (SEM and energy dispersive x-ray spectroscopy (EDS. Data were analyzed statistically by Fisher's test at 5% significance level. RESULTS: The analysis by optical microscopy revealed areas with color change suggestive of corrosion in the soldering point areas joining the band and the wire in all specimens of both groups, with no statistically significant difference between the groups (p=1. The peaks of chemical elements (Ni, Fe, Cr, O, C and P revealed by EDS were also similar in both groups. CONCLUSION: Color changes and peaks of chemical elements suggestive of corrosion were observed in the soldering point areas between the wire, silver brazing and band in both control and experimental groups, which indicate that the 0.12% chlorhexidine gluconate mouthrinses did not influence the occurrence of corrosion in situ.

  11. Electrochemical corrosion behavior of arc sprayed Zn-Al coatings

    Institute of Scientific and Technical Information of China (English)

    LIU Yan; ZHU Zi-xin; CHEN Yong-xiong; XU Bin-shi; MA Shi-ning; LI Zhuo-xin

    2004-01-01

    Cored wires and high velocity arc spraying (HVAS) technique were applied to produce high Al content Zn-Al alloy coatings on low carbon steel substrates. The electrochemical corrosion behaviors of Zn, Al and Zn-Al coatings were studied with potentiodynamic measurement in 5 % NaCl solution. Compared with pure Zn, pure Al and Zn-15Al coatings, Zn-26Al coatings show a higher corrosion resistance in salt solution. The potentiodynamic polarization tests show that the corrosion resistance of Zn-Al coatings increases as Al content is raised. Pure Al coating exhibits different electrochemical behaviors with other coatings. The corrosion initiated at the micro-pores of the coating and the underlying corrosion mechanism is very similar to that of the pitting corrosion.

  12. Electrochemical and quantum chemical studies of some indole derivatives as corrosion inhibitors for C38 steel in molar hydrochloric acid

    Energy Technology Data Exchange (ETDEWEB)

    Lebrini, M. [Laboratoire Materiaux et Molecules en Milieu Amazonien, CNRS 8172-UMR ECOFOG, Campus Trou Biran, Cayenne 97337, French Guiana (France); Robert, F. [Laboratoire Materiaux et Molecules en Milieu Amazonien, UAG-UMR ECOFOG, Campus Trou Biran, Cayenne 97337, French Guiana (France); Vezin, H. [Laboratoire de Chimie Organique et Macromoleculaire, UMR-CNRS 8009, USTL BatC4 F-59655 Villeneuve d' Ascq Cedex (France); Roos, C., E-mail: christophe.roos@guyane.univ-ag.f [Laboratoire Materiaux et Molecules en Milieu Amazonien, UAG-UMR ECOFOG, Campus Trou Biran, Cayenne 97337, French Guiana (France)

    2010-10-15

    A comparative study of 9H-pyrido[3,4-b]indole (norharmane) and 1-methyl-9H-pyrido[3,4-b]indole (harmane) as inhibitors for C38 steel corrosion in 1 M HCl solution at 25 {sup o}C was carried out. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were applied to study the metal corrosion behavior in the absence and presence of different concentrations of these inhibitors. The OCP as a function of time were also established. Cathodic and anodic polarization curves show that norharmane and harmane are a mixed-type inhibitors. Adsorption of indole derivatives on the C38 steel surface, in 1 M HCl solution, follows the Langmuir adsorption isotherm model. The {Delta}G{sub ads}{sup o} values were calculated and discussed. The potential of zero charge (PZC) of the C38 steel in inhibited solution was studied by the EIS method, and a mechanism for the adsorption process was proposed. Raman spectroscopy confirmed that indole molecules strongly adsorbed onto the steel surface. The electronic properties of indole derivates, obtained using the AM1 semi-empirical quantum chemical approach, were correlated with their experimental efficiencies using the linear resistance model (LR).

  13. Corrosion study of steels exposed over five years to the humid tropical atmosphere of Panama

    Energy Technology Data Exchange (ETDEWEB)

    Jaén, Juan A., E-mail: juan.jaen@up.ac.pa [Departamento de Química Física, Edificio de Laboratorios Científicos-VIP (Panama); Iglesias, Josefina [Laboratorio de Análisis Industriales y Ciencias Ambientales (Panama)

    2017-11-15

    The results of assessing five-year corrosion of low-carbon and conventional weathering steels exposed to the Panamanian tropical atmosphere is presented. Two different test sites, one in Panama City: 5 km from the shoreline of the Pacific Ocean, and another in the marine environment of Fort Sherman, Caribbean coast of Panama; namely, Fort Sherman Coastal site: 100 m from coastline. The corrosion products, formed in the skyward and earthward faces in the studied tropical environment, were mainly identified using room temperature and low temperature (15 K) Mössbauer spectroscopy, and ATR-FTIR. In all samples, lepidocrocite (γ-FeOOH) and goethite (α-FeOOH) were the main constituents. Some maghemite (γ-Fe{sub 2}O{sub 3}), was also identified in Tocumen by Mössbauer spectroscopy and traces of feroxyhyte (δ-FeOOH) using ATR-FTIR. The corrosion rate values obtained are discussed in light of the atmospheric exposure conditions and atmospheric pollutants.

  14. A study on structural analysis of highly corrosive melts at high temperature

    CERN Document Server

    Ohtori, N

    2002-01-01

    When sodium is burned at high temperature in the atmosphere, it reacts simultaneously with H sub 2 O in the atmosphere so that it can produce high temperature melt of sodium hydroxide as a solvent. If this melt includes peroxide ion (O sub 2 sup 2 sup -), it will be a considerably active and corrosive for iron so that several sodium iron double oxides will be produced as corrosion products after the reaction with steel structures. The present study was carried out in order to investigate the ability of presence of peroxide ion in sodium hydroxide solvent at high temperature and that of identification of the several corrosion products using laser Raman spectroscopy. The measurement system with ultraviolet laser was developed simultaneously in the present work to improve the ability of the measurement at high temperature. As results from the measurements, the possibility of the presence of peroxide ion was shown up to 823K in sodium peroxide and 823K in the melt of sodium hydroxide mixed with sodium peroxide. A...

  15. Electrochemical Impedance Spectroscopy Study on Corrosion Protection of Acrylate Nanocomposite on Mild Steel Doped Carbon Nanotubes

    Science.gov (United States)

    Mahmud, M. R.; Akhir, M. M.; Shamsudin, M. S.; Afaah, A. N.; Aadila, A.; Asib, N. A. M.; Alrokayan, Salman A. H.; Khan, Haseeb A.; Harun, M. K.; Rusop, M.; Abdullah, S.

    2015-05-01

    Acrylate:carbon nanotubes (A:CNTs) nanocomposite thin film was prepared by sol- gel technique. The corrosion coating protection of acrylate:carbon nanotubes (CNTs) nanocomposite thin film has been coated on mild steel characterised by electrochemical impedance spectrometer (EIS) measurement and equivalent circuit model are employed to analyse coating impedance for corrosion protection. In this study, 3.5 w/v % sodium chloride (NaCl) solution was immersed the acrylate:carbon nanotubes nanocomposite thin film. As the results, the surface morphology were found that there formation of carbon nanotubes with good distribution on acrylate-based coating. From EIS measurement, A:CNTs nanocomposite thin film with 0.4 w/v % contain of CNTs was exhibited the highest coating impedance from Nyquist graph after immersed in sodium chloride solution and may provide the excellent corrosion protection. The Bode plots have shown the impedance is high at the beginning from the time at high frequency and slightly decreases with value of frequency become smaller.

  16. Study of corrosion in steel sculptures by means of solid state voltammetry at paraffin-impregnated graphite electrodes

    OpenAIRE

    DOMENECH CARBO, ANTONIO; Roig Salom, José Luís; Domenech Carbo, Mª Teresa

    2006-01-01

    Solid-state voltammetry is used for studying the composition of corrosion products in a series of sculptures from the Contemporary Sculpture Collection of the Universidad Politècnica de Valencia (Spain). Upon attachment to paraffin-impregnated graphite electrodes, well-defined voltammetric responses were obtained upon immersion in 0.10 M HCl. A hematite with a variable degree of hydration and crystallinity, accompanied by FeO(OH) forms, is identified as the main corrosion product. La volta...

  17. Evaluation of steel corrosion by numerical analysis

    OpenAIRE

    Kawahigashi, Tatsuo

    2017-01-01

    Recently, various non-destructive and numerical methods have been used and many cases of steel corrosion are examined. For example, methods of evaluating corrosion through various numerical methods and evaluating macrocell corrosion and micro-cell corrosion using measurements have been proposed. However, there are few reports on estimating of corrosion loss with distinguishing the macro-cell and micro-cell corrosion and with resembling an actuality phenomenon. In this study, for distinguishin...

  18. Density functional theory and molecular dynamics simulation study on corrosion inhibition performance of mild steel by mercapto-quinoline Schiff base corrosion inhibitor

    Science.gov (United States)

    Saha, Sourav Kr.; Ghosh, Pritam; Hens, Abhiram; Murmu, Naresh Chandra; Banerjee, Priyabrata

    2015-02-01

    Corrosion inhibition mechanism of two mercapto-quinoline Schiff bases, eg., 3-((phenylimino)methyl)quinoline-2-thiol (PMQ) and 3-((5-methylthiazol-2-ylimino)methyl) quinoline-2-thiol (MMQT) on mild steel surface is investigated by quantum chemical calculation and molecular dynamics simulation. Quantum chemical parameters such as EHOMO, ELUMO, energy gap (ΔE), dipolemoment (μ), electronegativity (χ), global hardness (η) and fraction of electron transfers from the inhibitor molecule to the metallic atom surface (ΔN) have been studied to investigate their relative corrosion inhibition performance. Parameters like local reactive sites of the present molecule have been analyzed through Fukui indices. Moreover, adsorption behavior of the inhibitor molecules on Fe (1 1 0) surface have been analyzed using molecular dynamics simulation. The binding strength of the concerned inhibitor molecules on mild steel surface follows the order MMQT>PMQ, which is in good agreement with the experimentally determined inhibition efficiencies. In view of the above, our approach will be helpful for quick prediction of a potential inhibitor from a lot of similar inhibitors and subsequently in their rational designed synthesis for corrosion inhibition application following a wet chemical synthetic route.

  19. Graphene: corrosion-inhibiting coating.

    Science.gov (United States)

    Prasai, Dhiraj; Tuberquia, Juan Carlos; Harl, Robert R; Jennings, G Kane; Rogers, Bridget R; Bolotin, Kirill I

    2012-02-28

    We report the use of atomically thin layers of graphene as a protective coating that inhibits corrosion of underlying metals. Here, we employ electrochemical methods to study the corrosion inhibition of copper and nickel by either growing graphene on these metals, or by mechanically transferring multilayer graphene onto them. Cyclic voltammetry measurements reveal that the graphene coating effectively suppresses metal oxidation and oxygen reduction. Electrochemical impedance spectroscopy measurements suggest that while graphene itself is not damaged, the metal under it is corroded at cracks in the graphene film. Finally, we use Tafel analysis to quantify the corrosion rates of samples with and without graphene coatings. These results indicate that copper films coated with graphene grown via chemical vapor deposition are corroded 7 times slower in an aerated Na(2)SO(4) solution as compared to the corrosion rate of bare copper. Tafel analysis reveals that nickel with a multilayer graphene film grown on it corrodes 20 times slower while nickel surfaces coated with four layers of mechanically transferred graphene corrode 4 times slower than bare nickel. These findings establish graphene as the thinnest known corrosion-protecting coating.

  20. A New Approach of Studying Correlation between Outdoor Exposure and Indoor Accelerated Corrosion Test for High Polymer Materials

    Institute of Scientific and Technical Information of China (English)

    YANG Lixia; LI Xiaogang; ZHANG Sanping

    2006-01-01

    The correlation between outdoor exposure and indoor accelerated corrosion test for high polymer materials was investigated according to the variation of the functional group of exposure models aged. Environment aging intensities at different zones ( Wuhan and Lasa with the same latitude ) and the influences of indoor accelerating factors including water and ultraviolet on weathering performance of high polymer materials were also studied by comparing different indoor accelerated corrosion testing results. The experimental results show that: by testing variations of carbonyl exponent of polythene ( which represented the degradation behavior of highpolymer materials due to ultraviolet oxidation of double bond) and ultraviolet absorbance of polycarbonate ( which represented the degradation behavior of high polymer materials due to abevacuation of branched chain), the degradation behavior of high polymer materials could be studied. Carbonyl exponent of polythene exposed in Wuhan and Lasa for 1 year was equal to that exposed in indoor cycle ultraviolet for 128 h and 170 h, respectively, the ultraviolet absorbance of polycarbonate exposed in Wuhan for 1 year was equal to that exposed in indoor cycle ultraviolet for 240 h. The ratio of environment aging intensity of Lasa to Wuhan was around 1.2. With the prolongation of cycle accelerated ultraviolet exposure time, the variations of carbonyl exponent of polythene and the ultraviolet absorbance of polycarbonate were in the same shape of first order exponential decay curve. Accompanied with ultraviolet, the effect of water condensated on the sample on weathering performance of polythene was more significant than that of polycarbonate.

  1. Microbial-Influenced Corrosion of Corten Steel Compared with Carbon Steel and Stainless Steel in Oily Wastewater by Pseudomonas aeruginosa

    Science.gov (United States)

    Mansouri, Hamidreza; Alavi, Seyed Abolhasan; Fotovat, Meysam

    2015-07-01

    The microbial corrosion behavior of three important steels (carbon steel, stainless steel, and Corten steel) was investigated in semi petroleum medium. This work was done in modified nutrient broth (2 g nutrient broth in 1 L oily wastewater) in the presence of Pseudomonas aeruginosa and mixed culture (as a biotic media) and an abiotic medium for 2 weeks. The behavior of corrosion was analyzed by spectrophotometric and electrochemical methods and at the end was confirmed by scanning electron microscopy. The results show that the degree of corrosion of Corten steel in mixed culture, unlike carbon steel and stainless steel, is less than P. aeruginosa inoculated medium because some bacteria affect Corten steel less than other steels. According to the experiments, carbon steel had less resistance than Corten steel and stainless steel. Furthermore, biofilm inhibits separated particles of those steels to spread to the medium; in other words, particles get trapped between biofilm and steel.

  2. Study on the Synthesis and Corrosion Inhibition Performance of Mannich-Modified Imidazoline

    Directory of Open Access Journals (Sweden)

    Xiangjun Kong

    2016-07-01

    Full Text Available A novel Mannich-modified imidazoline (MMI as cationic emulsifier was synthesised for corrosion harm reduction, through three steps — acylation, cyclization, and Mannich reaction. The surface activity was characterized by determination of surface tensions and critical micelle concentration (CMC. The corrosion inhibition performance of five types of steels in the simulated corrosion solution in the presence of the MMI was investigated by static weight loss tests. The results showed that the MMI had good surface activities, with CMC of 19.8 μg g−1 and surface tension of 36.4 mN m−1. The corrosion test results indicated that the corrosion rates of different materials were decreased significantly, and degrees of corrosion inhibition were always higher than 80.0 %. The main inhibition mechanism was most likely due to the adsorption of the corrosion inhibitor on the steel surface, leading to the prevention of corrosion medium from the metal surface.

  3. Study on Interaction Relationship for Submarine Pipeline with Axial Corrosion Defects

    Institute of Scientific and Technical Information of China (English)

    CHEN Yan-fei; LI Xin; ZHOU Jing; GUAN Jiong

    2008-01-01

    Corrosion is one of the main reasons to cause the operation accident of submarine oil and gas transmission pipelines. As the major corrosion pattern in submarine pipelines, the effects of corrosion clusters consisting of the adjacent corrosion defects on failure pressure are investigated through non-linear large-deformation finite element method. Typically, the failure behavior and limit strength of submarine pipeline with axial groove-groove corrosion defect pair exposed to internal pressure are analyzed. The effects of corrosion depth and axial spacing between a pair of corrosion defects on failure pressure are concluded. An interaction relationship for corrosion defects in pipelines, as well as prediction formulations for assessing the remaining strength of corroded pipelines are proposed. The expressions based on the proposed interaction relationship give more accurate results than the methods used in the existing design guidelines.

  4. Corrosion monitoring as an integral component of an effective corrosion management program

    Energy Technology Data Exchange (ETDEWEB)

    Bich, N.N. [FORCE Technology Canada Inc., Calgary, AB (Canada)

    2004-07-01

    This paper presented 6 case studies of oil and sour gas transmission pipelines where the use of corrosion monitoring devices led to the early identification of ineffective mitigation measures. The field signature method inspection tool (FSM-IT) was used in all 6 cases. FSM-IT is a non-intrusive corrosion monitoring tool that consists of a geometric matrix of sensing pins that are permanently attached to an outer pipe wall. The sensing matrix wiring is coupled to a sensing matrix interface (SMI) to form an interface. With the occurrence of internal corrosion or erosion, the electrical field is changed and compared against the signature. Computer software is used to compare the new measurements against the original signature to produce metal loss values. The software is capable of trending the metal loss over time, calculating corrosion rates and creating 3D plots to illustrate accumulated wall loss over the whole matrix. The orientation of the corrosion can be determined from an evaluation of the plots. Case studies included details of pipeline length, corrosion mechanisms, and repair activities. Mitigation measures in the case studies included batching; continuous injection; and pigging. It was concluded that the FSM-IT corrosion mitigation tool is effective in monitoring mitigation effectiveness. 7 refs., 1 tab., 12 figs.

  5. Study on Mechanism of Concrete Failure Induced by Steel Corrosion under Externally Applied Direct Current

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    With the combination of electrochemical corrosion due to straycurrent in running tunnels of metro, the formula to determine the corrosion products of rebars in reinforced concrete subjected to externally applied direct current is proposed, and the influence of corrosion on stress in concrete is also discussed. Meanwhile, the concept of corrosion stress field and its mathematical formula are presented in the paper. Finally the failure mode of concrete and its shortest breaking time are also analyzed.

  6. Scattering length density profile of Ni film under controlled corrosion: A study in neutron reflectometry

    Indian Academy of Sciences (India)

    Surendra Singh; A K Poswal; S K Ghosh; Saibal Basu

    2008-11-01

    We report the density depth profile of an as-deposited Ni film and density profile for the same film after controlled electrochemical corrosion by chloride ions, measured by unpolarized neutron reflectometry. The neutron reflectometry measurement of the film after corrosion shows density degradation along the thickness of the film. The density profile as a function of depth, maps the growth of pitting and void networks due to corrosion. The profile after corrosion shows an interesting peaking nature.

  7. Electrochemical study of FeS corrosion in acid solutions in the presence of benzothiazolic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Chirita, P.; Samide, A.; Ciuciu, A. [Univ Craiova, Fac Chem, Craiova (Romania); Descostes, M.; Schlegel, M.L. [CEA Saclay, DEN, 91 - Gif sur Yvette (France)

    2009-06-15

    Complete text of publication follows: Iron monosulfide (FeS) exposed to acidic solutions containing oxidants can dissolve oxidatively [1, 2]. This corrosion releases toxic elements (heavy metals and arsenic) present in the FeS matrix. However, this corrosion may be altered by interaction with organic molecules. 2-(cyclohexyl-amino-mercapto)-benzothiazole (CMB) and 2-mercapto-benzothiazole (MBT) are known to inhibit corrosion of steel [3]. The present study investigated the effect of these molecules on FeS. The behaviour of synthetic FeS in acid solutions at 25 C in the presence and the absence of CMB or MBT was investigated using electrochemical measurements and microscopic analysis. The corrosion currents (i{sub corr}) were obtained from Tafel polarization plots [3]. The polarization resistance in absence and presence of inhibitors (R{sup 0}{sub p} and R{sub p}, respectively) were determined from electrochemical impedance spectroscopy. It was observed that both CMB and MBT reduce the oxidative (anodic) dissolution of FeS. For example, in 0.1 mol L{sup -1} HCl i{sub corr} decreases from 342 {mu}A cm{sup -2} (in the absence of inhibitors) to 65 {mu}A cm{sup -2} ([CMB] = 5*10{sup -4} mol L{sup -1}) and to 95.8 {mu}A cm{sup -2} ([MBT] = 5*10{sup -4} mol L{sup -1}). Instead R{sub p} increases from 33.4 {Omega} cm{sup 2} in the absence of inhibitors to 175.4 and to 119.3 {Omega} cm{sup 2} in the presence of CMB and MBT, respectively. These results indicate that CMB is a more efficient inhibitor than MBT. It was also found that the FeS surface coverage [{theta} = 1- (R{sup 0}{sub p}/R{sub p})] increases when inhibitor concentration augments from 2*10{sup -4} to 5*10{sup -4} mol L{sup -1}. This is in good agreement with microscopic images that indicate the formation of a protective film on the FeS surfaces corroded in presence of inhibitors. All these findings suggest that FeS corrosion can be substantially reduced by the formation of organic layers that may modify the

  8. A Study of Substituted Aliphatic Sulphides on the Corrosion Behaviour of Zinc in Ammonium Chloride Solution

    Directory of Open Access Journals (Sweden)

    R. Venckatesh

    2007-01-01

    Full Text Available Sulphur containing organic compounds decreases the corrosion rate by increasing the hydrogen over potential on zinc metal due to their electron donating groups. Their inhibiting effect was found to be associated with their adsorption on the active centers of the metal. The inhibition efficiencies of some aliphatic sulphides in ammonium chloride solution have been studied by weight loss studies, polarization and impedance measurements. The effect of substituent groups is correlated with their inhibition performance. These studies due to their relevance in Zn-Manganese dry batteries assume their importance.

  9. In-situ TEM Studies: Heat-treatment and Corrosion

    NARCIS (Netherlands)

    Malladi, S.R.K.

    2014-01-01

    Transmission electron microscopy (TEM) has been well known as a powerful characterisation tool to understand the structure and composition of various materials down to the atomic level. Over the years, several TEM studies have been carried out to understand the compositional, structural and morpholo

  10. Corrosion protection of copper by polypyrrole film studied by electrochemical impedance spectroscopy and the electrochemical quartz microbalance

    Science.gov (United States)

    Lei, Yanhua; Ohtsuka, Toshiaki; Sheng, Nan

    2015-12-01

    Polypyrrole (PPy) films were synthesized on copper in solution of sodium di-hydrogen phosphate and phytate for corrosion protection. The protection properties of PPy films were comparatively investigated in NaCl solution. During two months immersion, the PPy film doped with phytate anions, working as a cationic perm-selective membrane, inhibited the dissolution of copper to 1% of bare copper. Differently, the PPy film doped with di-hydrogen phosphate anions, possessing anionic perm-selectivity, was gradually reduced, and inhibited the dissolution to 7.8% of bare copper. Degradation of the PPy films was studied by comparing the electrochemical impedance spectroscopy change at different immersion time and Raman spectra change after immersion.

  11. Experimental Study on the Electrochemical Anti-Corrosion Properties of Steel Structures Applying the Arc Thermal Metal Spraying Method

    Directory of Open Access Journals (Sweden)

    Hong-Bok Choe

    2014-12-01

    Full Text Available The arc thermal metal spraying method (ATMSM provides proven long-term protective coating systems using zinc, aluminum and their alloys for steel work in a marine environment. This paper focuses on studying experimentally the anti-corrosion criteria of ATMSM on steel specimens. The effects of the types of spraying metal and the presence or absence of sealing treatment from the thermal spraying of film on the anti-corrosion performance of TMSM were quantitatively evaluated by electrochemical techniques. The results showed that ATMSM represented a sufficient corrosion resistance with the driving force based on the potential difference of more than approximately 0.60 V between the thermal spraying layer and the base substrate steel. Furthermore, it was found that the sealing treatment of specimens had suppressed the dissolution of metals, increased the corrosion potential, decreased the corrosion current density and increased the polarization resistance. Metal alloy Al–Mg (95%:5% by mass with epoxy sealing coating led to the most successful anti-corrosion performance in these electrochemical experiments.

  12. Analysis of Pipeline Steel Corrosion Data From NBS (NIST) Studies Conducted Between 1922-1940 and Relevance to Pipeline Management.

    Science.gov (United States)

    Ricker, Richard E

    2010-01-01

    Between 1911 and 1984, the National Bureau of Standards (NBS) conducted a large number of corrosion studies that included the measurement of corrosion damage to samples exposed to real-world environments. One of these studies was an investigation conducted between 1922 and 1940 into the corrosion of bare steel and wrought iron pipes buried underground at 47 different sites representing different soil types across the Unites States. At the start of this study, very little was known about the corrosion of ferrous alloys underground. The objectives of this study were to determine (i) if coatings would be required to prevent corrosion, and (ii) if soil properties could be used to predict corrosion and determine when coatings would be required. While this study determined very quickly that coatings would be required for some soils, it found that the results were so divergent that even generalities based on this data must be drawn with care. The investigators concluded that so many diverse factors influence corrosion rates underground that planning of proper tests and interpretation of the results were matters of considerable difficulty and that quantitative interpretations or extrapolations could be done "only in approximate fashion" and attempted only in the "restricted area" of the tests until more complete information is available. Following the passage of the Pipeline Safety Improvement Act in 2002 and at the urging of the pipeline industry, the Office of Pipeline Safety of the U.S. Department of Transportation approached the National Institute of Standards and Technology (NBS became NIST in 1988) and requested that the data from this study be reexamined to determine if the information handling and analysis capabilities of modern computers and software could enable the extraction of more meaningful information from these data. This report is a summary of the resulting investigations. The data from the original NBS studies were analyzed using a variety of

  13. Analysis of Pipeline Steel Corrosion Data From NBS (NIST) Studies Conducted Between 1922–1940 and Relevance to Pipeline Management

    Science.gov (United States)

    Ricker, Richard E.

    2010-01-01

    Between 1911 and 1984, the National Bureau of Standards (NBS) conducted a large number of corrosion studies that included the measurement of corrosion damage to samples exposed to real-world environments. One of these studies was an investigation conducted between 1922 and 1940 into the corrosion of bare steel and wrought iron pipes buried underground at 47 different sites representing different soil types across the Unites States. At the start of this study, very little was known about the corrosion of ferrous alloys underground. The objectives of this study were to determine (i) if coatings would be required to prevent corrosion, and (ii) if soil properties could be used to predict corrosion and determine when coatings would be required. While this study determined very quickly that coatings would be required for some soils, it found that the results were so divergent that even generalities based on this data must be drawn with care. The investigators concluded that so many diverse factors influence corrosion rates underground that planning of proper tests and interpretation of the results were matters of considerable difficulty and that quantitative interpretations or extrapolations could be done “only in approximate fashion” and attempted only in the “restricted area” of the tests until more complete information is available. Following the passage of the Pipeline Safety Improvement Act in 2002 and at the urging of the pipeline industry, the Office of Pipeline Safety of the U.S. Department of Transportation approached the National Institute of Standards and Technology (NBS became NIST in 1988) and requested that the data from this study be reexamined to determine if the information handling and analysis capabilities of modern computers and software could enable the extraction of more meaningful information from these data. This report is a summary of the resulting investigations. The data from the original NBS studies were analyzed using a variety of

  14. Carbon Dioxide Corrosion:

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup

    2008-01-01

    CO2 corrosion is a general problem in the industry and it is expensive. The focus of this study is an oil gas production related problem. CO2 corrosion is observed in offshore natural gas transportation pipelines. A general overview of the problem is presented in chapter 1. The chemical system co...

  15. Study of mechanical, physical, and corrosion behavior of 0.5% cobalt alloyed austempered ductile iron

    Science.gov (United States)

    Abdullah, Bulan; Jaffar, Ahmed; Alias, Siti Khadijah; Ramli, Abdullah; Izham, Mohd Faizul

    2010-03-01

    Objectives: The purpose of this research was to determine the mechanical properties and corrosion behavior of 0.5% Co-DI before and after heat treatment and compare with commercial ductile iron. Methods: Molten metal of newly developed ductile iron which alloyed with 0.5% Cobalt produced through CO2 sand casting method. The specimens then performed preheat to 500°C in an hour then oil quenched. Specimens then performed annealing to 900°C in half an hour before oil quenched again. 500°C, 600°C and 700°C austempering temperature had been selected subjected to the specimens in half an hour before cooled to room temperature. The tests involved are microstructure analysis which included nodule count and phase analysis, polarization test, spectrometer test, density test, tensile test (ASTM E 8M), hardness test and impact test (ASTM A327) on as cast and austempered specimen. Results: 0.5% Cobalt alloyed austempered ductile iron with 500°C austempered temperature is the optimum temperature for 0.5% Co-ADI. It's not only increase the nodule count in the content, but also improve the mechanical properties such as impact toughness and tensile strength. Corrosion rate of 0.5% Co-DI also improved compare to unalloyed DI.

  16. Corrosion-resistant metallic coatings

    OpenAIRE

    F. Presuel-Moreno; M.A. Jakab; N. Tailleart; Goldman, M.; J. R. Scully

    2008-01-01

    We describe recent computational and experimental studies on the corrosion properties of metallic coatings that can be tailored (tuned) to deliver up to three corrosion-inhibiting functions to an underlying substrate. Attributes are tuned by a selection of alloy compositions and nanostructures, ideally in alloy systems that offer flexibility of choice to optimize the corrosion-resisting properties. An amorphous Al-based coating is tuned for corrosion protection by on-demand release of ionic i...

  17. Postcoital Sperm Assessment Comparative Study.

    Science.gov (United States)

    Pelekanos, Michael J

    2015-11-01

    This postcoital sperm assessment study was performed over a 10 month time period (November 2014-August 2015). Fifteen couples enrolled in the study. The study was a non-blinded, non-randomized, single-center comparison study comparing The Stork® OTC (Rinovum Women's Health, Monroeville, PA) to natural intercourse (NI), using the subjects as their own control/baseline. This was an efficacy study designed to compare the number of sperm in the cervical mucus following the use of The Stork OTC conception aid with the number of sperm in the cervical mucus following natural intercourse. Subjects used both The Stork OTC conception system and the natural intercourse method to evaluate concentrations of sperm in the cervical mucus. Post-coital test (PCT) data was collected demonstrating higher concentrations of sperm within the cervical mucus with The Stork OTC conception system versus natural intercourse for 85% of test subjects in this study. Of the 15 couples enrolled in the study, 2 were lost to follow-up. Mean age for male subjects was 31.7 +/ 5.4 years of age and mean age for female subjects was 29.7+/- 5.4. The average sperm score value of the 85% of test subjects with higher sperm concentrations from The Stork OTC was 3.23 times the score value of sperm concentration compared to natural intercourse. The remaining 15% of test subjects showed no change in sperm score value between The Stork OTC and natural intercourse.

  18. STUDY ON THE EROSION-CORROSION BEHAVIOR OF STEELS AND THERMAL SPRAYED COATINGS

    Institute of Scientific and Technical Information of China (English)

    ChenHuahui; ZhaoHuiyou; ShooHesheng; ZhaoShanzhon

    1996-01-01

    16Mn steel, 1Cr18Ni9 stainless steel, thermal sprayed Al2O3-TiO2 ceramic coating and nylonl010-5%Al2O3 coating were tested with an erosion-corrosion tester.The effects of pH values and slurry velocities on the erosion-corrosion behavior of the materials tested were determined. The erosion-corrosion behavior of the materials tested changes with pH values and presents different change tendencies. The erosion-corrosion rates of the materials are increased with slurry velocities. The erosion-corrosion mechanisms for the steels and the coatings are considerably different.

  19. Corrosion Behavior of V2AlC and Cr2AlC Compared with SS 316L in NaOH at Four Temperatures

    Directory of Open Access Journals (Sweden)

    Rana A. Anaee

    2015-06-01

    Full Text Available This work involves the manufacturing of MAX phase materials include V2AlC and Cr2AlC using powder metallurgy as a new class of materials which characterized by regular crystals in lattice. Corrosion behavior of these materials was investigated by Potentiostat to estimate corrosion resistance and compared with the most resistant material represented by SS 316L. The experiments were carried out in 0.01N of NaOH solution at four temperatures in the range of 30–60oC. Polarization resistance values which calculated by Stern-Geary equation indicated that the MAX phase materials more resistant than SS 316L. Also cyclic polarization tests confirmed the resistivity of MAX phase materials through disappears of hysteresis loop.

  20. The influence of organic structure and rare earth metal cation on the corrosion efficiency observed on AS1020 steel compared with La(4OHCin3

    Directory of Open Access Journals (Sweden)

    Marianne Seter

    2015-01-01

    Full Text Available Whilst the corrosion protection of steel in aqueous chloride environments by the rare earth inhibitor lanthanum 4-hydroxycinnamate is well known, the influence of the structural variation of the organic component as well as the nature of the metal centre has not previously been addressed. Herein we show that praseodymium 4-hydroxy cinnamate is comparable to its lanthanum counterpart in aqueous solution. On the other hand, cerium 4-hydroxycinnamate and lanthanum 2-hydroxycinnamate show poor corrosion protection performance while lanthanum 3-hydroxycinnamate provides a level of inhibition between these. These differences are shown to be related to the speciation in solution and are postulated to be linked to steric influences which are likely to affect the bonding environment within the rare earth compound itself, as well as its bonding with the steel substrate.

  1. Studies on Indian bentonite as the carrying medium in corrosion inhibitive compositions for ferrus metals

    Directory of Open Access Journals (Sweden)

    B. Sanyal

    1959-10-01

    Full Text Available A new type of preservative based on chemical inhibitive incorporated in a suspension of bentonite in water was developed by Sanyal &Preston which proved as efficacious as petroleum base compositions for protection of steel against corrosion during storage and promised to be useful in some fields where use of petroleum base compositions was not feasible. In the present investigation, the performance o f Indian bentonite as the carrying medium for a wide range of chemical inhibitors and their mixtures, ha8 been studied.

  2. A theoretical study on the inhibition efficiencies of some amino acids as corrosion inhibitors of nickel

    Energy Technology Data Exchange (ETDEWEB)

    Gece, Goekhan, E-mail: gokhangc@gmail.co [Department of Physical Chemistry, Faculty of Science, Ankara University, Besevler, 06100 Ankara (Turkey); Bilgic, Semra [Department of Physical Chemistry, Faculty of Science, Ankara University, Besevler, 06100 Ankara (Turkey)

    2010-10-15

    To clarify the inhibition efficiencies of a total of 12 amino acids for the corrosion of nickel in acidic medium, a density functional theory (DFT) study was carried out using the B3LYP/LANL2DZ method. Quantum chemical descriptors such as the energy of highest occupied molecular orbital (E{sub HOMO}), energy of lowest unoccupied molecular orbital (E{sub LUMO}), and the energy gap ({Delta}E) were calculated. Equations were proposed using linear regression analysis to determine the most effective parameter on inhibition efficiency. The theoretically obtained results were found to be consistent with the experimental data reported.

  3. Decomposition studies of no-clean solder flux systems in connection with corrosion reliability of electronics

    DEFF Research Database (Denmark)

    Conseil, Helene; Jellesen, Morten Stendahl; Verdingovas, Vadimas

    2013-01-01

    One of the predominant factors for accelerated corrosion in electronics is the intrinsic contamination on Printed Circuit Board Assemblies (PCBAs) originating from the soldering process used for component mounting. However, the amount, distribution, and morphology of flux residue vary considerably...... such as electrochemical migration resulting in intermittent or permanent failures. This paper summarizes the investigations on decomposition of some typical no-clean flux systems (WOA based) which are used today for the electronic manufacturing. The change in flux chemistry was studied as a function of temperature...

  4. A STUDY OF LEAKAGE OF TRACE METALS FROM CORROSION OF THE MUNICIPAL DRINKING WATER DISTRIBUTION SYSTEM

    Directory of Open Access Journals (Sweden)

    M.R SHA MANSOURI

    2003-09-01

    Full Text Available Introduction: A high portion of lead and copper concentration in municipal drinking water is related to the metallic structure of the distribution system and facets. The corrosive water in pipes and facets cause dissolution of the metals such as Pb, Cu, Cd, Zn, Fe and Mn into the water. Due to the lack of research work in this area, a study of the trace metals were performed in the drinking water distribution system in Zarin Shahr and Mobareke of Isfahan province. Methods: Based on the united states Environmental protection Agency (USEPA for the cities over than 50,000 population such as Zarin Shahr and Mobareke, 30 water samples from home facets with the minimum 6 hours retention time of water in pipes, were collected. Lead and cadmium concentration were determined using flameless Atomic Absorption. Cupper, Zinc, Iron and Manganese were determined using Atomic Absorption. Results: The average concentration of Pb, Cd, Zn, Fe and Mn in water distribution system fo Zarin Shahr were 5.7, 0.1, 80, 3042, 23065 and in Mobareke were 7.83, 0.8,210,3100, 253, 17µg respectively. The cocentration of Pb, Cd and Zn were zero at the beginning of the water samples from the municipal drinking water distribution system for both cities. Conclusion: The study showed that the corrosion by products (such as Pb, Cd and Zn was the results of dissolution of the galvanized pipes and brass facets. Lead concentration in over that 10 percent of the water samples in zarin shahr exceeded the drinking water standard level, which emphasize the evaluation and control of corrosion in drinking water distribution systems.

  5. Improvement of carbon corrosion resistance through heat-treatment in polymer electrolyte membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Y.J.; Oh, H.S.; Kim, H. [Yonsei Univ., Seoul (Korea, Republic of). Dept. of Chemical and Biomolecular Engineering

    2010-07-01

    Electrochemical corrosion of carbon in the catalyst layer of polymer electrolyte membrane fuel cells (PEMFCs) is a critical factor in limiting their durability. The corrosion rate increases during the iterative abnormal operating conditions known as reverse current phenomenon. The corrosion causes a decrease of the active surface of the platinum (Pt) catalyst. The graphitization of carbon increases corrosion resistance, and the hydrophobicity of the carbon surface can also play an important role in decreasing carbon corrosion. This study investigated the effect of heat-treating carbon nanofibers (CNFs) for use in PEMFC applications. The aim of the study was to determine if heat treatments modified the carbon surface by eliminating the oxygen functional group and increasing hydrophobicity. The electrochemical carbon corrosion of CNFs were compared after heat treatments at various temperatures. Mass spectrometry was used to measure electrochemical carbon corrosion by monitoring the amounts of carbon dioxide (CO{sub 2}) produced during the electrochemical oxidation process. 2 refs.

  6. High Temperature Corrosion studies on Pulsed Current Gas Tungsten Arc Welded Alloy C-276 in Molten Salt Environment

    Science.gov (United States)

    Manikandan, M.; Arivarasu, M.; Arivazhagan, N.; Puneeth, T.; Sivakumar, N.; Murugan, B. Arul; Sathishkumar, M.; Sivalingam, S.

    2016-09-01

    Alloy C-276 is widely used in the power plant environment due to high strength and corrosion in highly aggressive environment. The investigation on high- temperature corrosion resistance of the alloy C-276 PCGTA weldment is necessary for prolonged service lifetime of the components used in corrosive environments. Investigation has been carried out on Pulsed Current Gas Tungsten Arc Welding by autogenous and different filler wires (ERNiCrMo-3 and ERNiCrMo-4) under molten state of K2SO4-60% NaCl environment at 675oC under cyclic condition. Thermogravimetric technique was used to establish the kinetics of corrosion. Weight gained in the molten salt reveals a steady-state parabolic rate law while the kinetics with salt deposits displays multi-stage growth rates. PCGTA ERNiCrMo-3 shows the higher parabolic constant compared to others. The scale formed on the weldment samples upon hot corrosion was characterized by using X-ray diffraction, SEM and EDAX analysis to understand the degradation mechanisms. From the results of the experiment the major phases are identified as Cr2O3, Fe2O3, and NiCr2O4. The result showed that weld fabricated by ERNiCrMo-3 found to be more prone to degradation than base metal and ERNiCrMo-4 filler wire due to higher segregation of alloying element of Mo and W in the weldment

  7. Study on the Corrosion Mechanism of Zn-5Al-0.5Mg-0.08Si Coating

    Directory of Open Access Journals (Sweden)

    Shiwei Li

    2011-01-01

    Full Text Available A new type of hot-dip Zn-5Al-0.5Mg-0.08Si and Zn-5Al alloy coatings was performed on the cold rolled common steel. The hot-dip process was executed by self-made hot-dip galvanising simulator. SEM and EDS test results demonstrated that Mg was mainly distributed in crystal boundaries. XRD test results showed that the corrosion product of Zn-5Al-0.5Mg-0.08Si alloy coating was almost Zn5(OH8C12⋅H2O. The features of Zn5(OH8C12⋅H2O are low electric conductivity, insolubility and good adhesion.The corrosion resistance of alloy-coated steels was detected by neutral salt spray test. The microstructural characterization of the coating surface after neutral salt spray test and removing the corrosion products revealed that the corrosion process of Zn-5Al-0.5Mg-0.08Si coating was uniform and the coating surface was almost flat. As a result, the corrosion resistance of Zn-5Al-0.5Mg-0.08Si coating has a remarkable improvement with a factor of 9.2 compared with that of Zn-5Al coating.

  8. THE STUDY OF HENNA LEAVES EXTRACT AS GREEN CORROSION INHIBITOR FOR MILD STEEL IN ACETIC ACID.

    Directory of Open Access Journals (Sweden)

    H. G. Chaudhari

    2016-05-01

    Full Text Available The inhibitive action of henna leaves extract on mild steel in acetic acid solution have been investigated by weight-loss, A C impedence and potentiodynamic polarization measurements. The study indicates that as acid concentration increases corrosion rate increases. The corrosion inhibition efficiency increases with increase in concentration of extract. The result obtained revealed that henna leaves extract act as efficient inhibitor. The adsorption of the henna leaves extract obeyed Langmuir adsorption isotherm. The calculated thermodynamic parameters indicated that the adsorption was a spontaneous, exothermic process accompanied by an increase in entropy. Cathodic and anodic polarization curves show that henna leaves extract is a mixed-type inhibitor. Normal 0 false false false EN-IN X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}   ABSTRACT:    The inhibitive action of henna leaves extract on mild steel in acetic acid solution have been investigated by weight-loss, A C impedence and potentiodynamic polarization measurements. The study indicates that as acid concentration increases corrosion rate increases. The corrosion inhibition efficiency increases with increase in concentration of extract. The result obtained revealed that henna leaves extract act as efficient inhibitor. The adsorption of the henna leaves

  9. Study of the Intergranular Corrosion of Sensitized UNS S31803 Stainless Steel in Transpassive Region

    Science.gov (United States)

    Morshed Behbahani, Khashayar; Najafisayar, Pooria; Pakshir, Mahmoud

    2016-08-01

    In this study, intergranular corrosion behavior of UNS S31803 duplex stainless steel was investigated using conventional potentiodynamic polarization, double loop electrochemical potentiokinetic reactivation (DLEPR), and electrochemical impedance spectroscopy (EIS) technique carried out at different potentials in the transpassive region. Different types of heat treatments were used to obtain samples with different degrees of sensitization. The results of the DLEPR tests showed that the solution-annealed sample and that was sensitized for half an hour would be considered as nonsensitized ones. Moreover, the sample that was sensitized for 24 h exhibits the highest value of the degree of sensitization. Polarization test results showed a typical active-passive behavior from which the transpassive potential range was determined and used as the range of the applied DC bias in the EIS experiments. Three different AC responses (including capacitive and inductive responses) were observed depending on the value of applied DC bias in the EIS experiments. In addition, it was observed that the presence of the second inductive loop at high applied DC bias is due to the adsorption of nonsoluble corrosion products on the surface of the samples. Moreover, the fitted values to the charge transfer and polarization resistances ( R ct and R P) decreased as the sensitization time increased from 30 min to 24 h. Such observations were in good accordance with the metallographic examination of the corroded surfaces, carried out by optical and scanning electron microscopy techniques, revealing discontinuous grain boundary attack in nonsensitized samples and a continuous network of grain boundary attack in the case of sensitized ones. Moreover, as the applied DC bias increases the ferrite phase attack also occurs in the sensitized samples. In addition, approximately no pitting corrosion was observed on the surface of the corroded samples which is in accordance with their respective cyclic

  10. Ultra-high temperature steam corrosion of complex silicates for nuclear applications: A computational study

    Science.gov (United States)

    Rashkeev, Sergey N.; Glazoff, Michael V.; Tokuhiro, Akira

    2014-01-01

    Stability of materials under extreme conditions is an important issue for safety of nuclear reactors. Presently, silicon carbide (SiC) is being studied as a cladding material candidate for fuel rods in boiling-water and pressurized water-cooled reactors (BWRs and PWRs) that would substitute or modify traditional zircaloy materials. The rate of corrosion of the SiC ceramics in hot vapor environment (up to 2200 °C) simulating emergency conditions of light water reactor (LWR) depends on many environmental factors such as pressure, temperature, viscosity, and surface quality. Using the paralinear oxidation theory developed for ceramics in the combustion reactor environment, we estimated the corrosion rate of SiC ceramics under the conditions representing a significant power excursion in a LWR. It was established that a significant time - at least 100 h - is required for a typical SiC braiding to significantly degrade even in the most aggressive vapor environment (with temperatures up to 2200 °C) which is possible in a LWR at emergency condition. This provides evidence in favor of using the SiC coatings/braidings for additional protection of nuclear reactor rods against off-normal material degradation during power excursions or LOCA incidents. Additionally, we discuss possibilities of using other silica based ceramics in order to find materials with even higher corrosion resistance than SiC. In particular, we found that zircon (ZrSiO4) is also a very promising material for nuclear applications. Thermodynamic and first-principles atomic-scale calculations provide evidence of zircon thermodynamic stability in aggressive environments at least up to 1535 °C.

  11. Corrosion of Carbon Steel and Corrosion-Resistant Rebars in Concrete Structures Under Chloride Ion Attack

    Science.gov (United States)

    Mohamed, Nedal; Boulfiza, Mohamed; Evitts, Richard

    2013-03-01

    Corrosion of reinforced concrete is the most challenging durability problem that threatens reinforced concrete structures, especially structures that are subject to severe environmental conditions (i.e., highway bridges, marine structures, etc.). Corrosion of reinforcing steel leads to cracking and spalling of the concrete cover and billions of dollars are spent every year on repairing such damaged structures. New types of reinforcements have been developed to avoid these high-cost repairs. Thus, it is important to study the corrosion behavior of these new types of reinforcements and compare them to the traditional carbon steel reinforcements. This study aimed at characterizing the corrosion behavior of three competing reinforcing steels; conventional carbon steel, micro-composite steel (MMFX-2) and 316LN stainless steel, through experiments in carbonated and non-carbonated concrete exposed to chloride-laden environments. Synthetic pore water solutions have been used to simulate both cases of sound and carbonated concrete under chloride ions attack. A three-electrode corrosion cell is used for determining the corrosion characteristics and rates. Multiple electrochemical techniques were applied using a Gamry PC4™ potentiostat manufactured by Gamry Instruments (Warminster, PA). DC corrosion measurements were applied on samples subjected to fixed chloride concentration in the solution.

  12. Mössbauer study of oxide films of Fe-, Sn-, Cr- doped zirconium alloys during corrosion in autoclave

    Science.gov (United States)

    Filippov, V. P.; Bateev, A. B.; Lauer, Yu. A.

    2016-12-01

    Mössbauer investigations were used to compare iron atom states in oxide films of binary Zr-Fe, ternary Zr-Fe-Cu and quaternary Zr-Fe-Cr-Sn alloys. Oxide films are received in an autoclave at a temperature of 350-360 °C and at pressure of 16.8 MPa. The corrosion process decomposes the intermetallic precipitates in alloys and forms metallic iron with inclusions of chromium atoms α-Fe(Cr), α-Fe(Cu), α-Fe 2O3 and Fe 3O4 compounds. Some iron ions are formed in divalent and in trivalent paramagnetic states. The additional doping influences on corrosion kinetics and concentration of iron compounds and phases formed in oxide films. It was shown the correlation between concentration of iron in different chemical states and corrosion resistance of alloys.

  13. Mössbauer study of oxide films of Fe-, Sn-, Cr- doped zirconium alloys during corrosion in autoclave

    Energy Technology Data Exchange (ETDEWEB)

    Filippov, V. P., E-mail: vpfilippov@mephi.ru; Bateev, A. B.; Lauer, Yu. A. [National Research Nuclear University “MEPhI” (Moscow Engineering Physics Institute) (Russian Federation)

    2016-12-15

    Mössbauer investigations were used to compare iron atom states in oxide films of binary Zr-Fe, ternary Zr-Fe-Cu and quaternary Zr-Fe-Cr-Sn alloys. Oxide films are received in an autoclave at a temperature of 350–360 °C and at pressure of 16.8 MPa. The corrosion process decomposes the intermetallic precipitates in alloys and forms metallic iron with inclusions of chromium atoms α–Fe(Cr), α–Fe(Cu), α–Fe {sub 2}O{sub 3} and Fe {sub 3}O{sub 4} compounds. Some iron ions are formed in divalent and in trivalent paramagnetic states. The additional doping influences on corrosion kinetics and concentration of iron compounds and phases formed in oxide films. It was shown the correlation between concentration of iron in different chemical states and corrosion resistance of alloys.

  14. A study on the mechanism of stress corrosion cracking of duplex stainless steels in hot alkaline-sulfide solution

    Science.gov (United States)

    Chasse, Kevin Robert

    Duplex stainless steels (DSS) generally have superior strength and corrosion resistance as compared to most standard austenitic and ferritic stainless grades owing to a balanced microstructure of austenite and ferrite. As a result of having favorable properties, DSS have been selected for the construction of equipment in pulp and paper, chemical processing, nuclear, oil and gas as well as other industries. The use of DSS has been restricted in some cases because of stress corrosion cracking (SCC), which can initiate and grow in either the ferrite or austenite phase depending on the environment. Thorough understanding of SCC mechanisms of DSS in chloride- and hydrogen sulfide-containing solutions has been useful for material selection in many environments. However, understanding of SCC mechanisms of DSS in sulfide-containing caustic solutions is limited, which has restricted the capacity to optimize process and equipment design in pulp and paper environments. Process environments may contain different concentrations of hydroxide, sulfide, and chloride, altering corrosion and SCC susceptibility of each phase. Crack initiation and growth behavior will also change depending on the relative phase distribution and properties of austenite and ferrite. The role of microstructure and environment on the SCC of standard grade UNS S32205 and lean grade UNS S32101 in hot alkaline-sulfide solution were evaluated in this work using electrochemical, film characterization, mechanical testing, X-ray diffraction, and microscopy techniques. Microstructural aspects, which included residual stress state, phase distribution, phase ratio, and microhardness, were related to the propensity for SCC crack initiation in different simulated alkaline pulping liquors at 170 °C. Other grades of DSS and reference austenitic and superferritic grades of stainless steel were studied using exposure coupons for comparison to understand compositional effects and individual phase susceptibility

  15. An Electrochemical Evaluation on the Corrosion of Weld Zone in Cold Arc Welding of the Cast Iron

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Kyung Man; Lee, Myung Hoon; Kim, Ki Joon [Korea Maritime University, Busan (Korea, Republic of); Kim, Jin Gyeong [Korea Institute of Marine and Frsheries Technology, Busan (Korea, Republic of)

    2008-04-15

    Cold arc welding of cast iron has been widely used with repair welding of metal structures. However its welding is often resulted in the galvanic corrosion between weld metal zone and heat affected zone(HAZ) due to increasing of hardness. In this study, corrosion properties such as hardness, corrosion potential, surface microstructures, and variation of corrosion current density of welding zone with parameters of used electrodes for cast iron welding were investigated with an electrochemical evaluation. Hardness of HAZ showed the highest value compared to other welding zone regardless of kinds of used electrodes for cast iron welding. And its corrosion potential was also shifted to more negative direction than other welding zone. In addition, corrosion current density of WM in polarization cures was qualitatively smaller than that of HAZ. Therefore galvanic corrosion may be apparently observed at HAZ. However galvanic corrosion may be somewhat controlled by using an optimum welding electrode.

  16. Study on Corrosion of the Foam Glass Anti-corrosion Lining%泡沫玻璃砖防腐内衬腐蚀研究

    Institute of Scientific and Technical Information of China (English)

    黎优霞; 冀运东

    2015-01-01

    Etching solution leaked from the thermal power plant wet chimney, which adopted domestic foam glass anti-corrosion lining and worked for a period of time. The performance of the foam glass anti-corrosion lining of it was studied in this paper. The properties of the foam glasses and plaster picking from the chimney lining were characterized by EDS and FT-IR. The results showed that the alkali metals (including Fe, K, Al, Na, Mg and so on) in the domestic foam glasses reacted with the acid corrosive media of the wet gas, which gave rise to the destruction of the closed pore structure and crisp cracking of the bricks; meanwhile, pendant groups on the polysiloxane matrix shed and Si-O-Si rigid structure increased in the main chain, which result in the loss of elasticity and adhesion of the plaster, then the foam dlass anti-corrosion lining fell off.%采用国产泡沫玻璃砖防腐内衬的火电厂湿烟囱,运行一段时间后,出现严重的渗透腐蚀现象。本文以湿烟囱排烟筒上脱落的泡沫玻璃砖为实验对象,利用EDS和FT-IR分别研究了国产泡沫玻璃砖和有机硅防腐胶泥的腐蚀状况及原理。结果表明,国产泡沫玻璃砖中含有Fe、K、Al、Na、Mg等碱金属,遇酸反应,导致砖体密闭孔隙结构破坏,酥化开裂,失去防腐作用;聚硅氧烷基体的侧基脱落,主链中Si-O-Si刚性结构增多,胶泥失去弹性和粘接性,导致防腐内衬整体脱落。

  17. Corrosion behavior of friction stir welded AZ31B Mg alloy - Al6063 alloy joint

    Directory of Open Access Journals (Sweden)

    B. Ratna Sunil

    2016-12-01

    Full Text Available In the present work, AZ31B Mg alloy and Al6063 alloy-rolled sheets were successfully joined by friction stir welding. Microstructural studies revealed a sound joint with good mechanical mixing of both the alloys at the nugget zone. Corrosion performance of the joint was assessed by immersing in 3.5% NaCl solution for different intervals of time and the corrosion rate was calculated. The joint has undergone severe corrosion attack compared with both the base materials (AZ31B and Al6063 alloys. The predominant corrosion mechanism behind the high corrosion rate of the joint was found to be high galvanic corrosion. From the results, it can be suggested that the severe corrosion of dissimilar Mg–Al joints must be considered as a valid input while designing structures intended to work in corroding environment.

  18. [Comparative studies of face recognition].

    Science.gov (United States)

    Kawai, Nobuyuki

    2012-07-01

    Every human being is proficient in face recognition. However, the reason for and the manner in which humans have attained such an ability remain unknown. These questions can be best answered-through comparative studies of face recognition in non-human animals. Studies in both primates and non-primates show that not only primates, but also non-primates possess the ability to extract information from their conspecifics and from human experimenters. Neural specialization for face recognition is shared with mammals in distant taxa, suggesting that face recognition evolved earlier than the emergence of mammals. A recent study indicated that a social insect, the golden paper wasp, can distinguish their conspecific faces, whereas a closely related species, which has a less complex social lifestyle with just one queen ruling a nest of underlings, did not show strong face recognition for their conspecifics. Social complexity and the need to differentiate between one another likely led humans to evolve their face recognition abilities.

  19. Polarization Studies on Inhibitory Effect of Chromates and Dichromates on Corrosion of Tin Coated Steel in 0.5M Monochloroacetic Acid

    Directory of Open Access Journals (Sweden)

    Sangita Sharma

    2008-01-01

    Full Text Available Chromates and Dichromates have been tested for its inhibitory effects towards tin coated steel in 0.5M monochloroacetic acid. The corrosion behaviour of potassium chromate, sodium chromate, potassium dichromate, sodium dichromate and ammonium dichromate was studied by polarization curves, Tafel parameters like Tafel slopes, extrapolation of cathodic Tafel line and intersection of cathodic and anodic line at open circuit potential in presence of inhibitors have been tabulated along with other electrochemical parameters and corrosion current have been calculated from Tafel lines. The efficiencies are calculated and compared reasonably well with those obtained from loss in weight data. All the inhibitors induce a significant increase of potential positive and direction accounts for cathodic polarization. The Icorr has also been calculated and that accounts well for cathodic reactions in presence of chromates and dichromates as inhibitors.

  20. A Study on the Residual Stress Improvement of PWSCC(Primary Water Stress Corrosion Cracking) in DMW(Dissimilar Metal Weld)

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sung Sik; Kim, Seok Hun; Lee, Seung Gun [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of); Park, Heung Bae [KEPCO Engineering and Construction Company, Daejeon (Korea, Republic of)

    2010-10-15

    Since 2000s, most of the cracks are found in welds, especially in (DMW) dissimilar metal welds such as pressurizer safety relief nozzle, reactor head penetration, reactor bottom mounted instrumentation (BMI), and reactor nozzles. Even the cracks are revealed as a primary water stress corrosion cracking (PWSCC), it is difficult to find the cracks by current non destructive examination. The PWSCC is occurred by three incident factors, such as susceptible material, environmental corrosive condition, and welding residual stress. If one of the three factors can be erased or decreased, the PWSCC could be prevented. In this study, we performed residual stress analysis for DMW and several residual stress improvement methods. As the preventive methods of PWSCC, we used laser peening(IP) method, inlay weld(IW) method, and induction heating stress improvement(IHSI) method. The effect of residual stress improvement for preventive methods was compared and discussed by finite element modeling and residual stress of repaired DMW

  1. Comparative study of approaches to estimate pipe break frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Simola, K.; Pulkkinen, U.; Talja, H.; Saarenheimo, A.; Karjalainen-Roikonen, P. [VTT Industrial Systems (Finland)

    2002-12-01

    The report describes the comparative study of two approaches to estimate pipe leak and rupture frequencies for piping. One method is based on a probabilistic fracture mechanistic (PFM) model while the other one is based on statistical estimation of rupture frequencies from a large database. In order to be able to compare the approaches and their results, the rupture frequencies of some selected welds have been estimated using both of these methods. This paper highlights the differences both in methods, input data, need and use of plant specific information and need of expert judgement. The study focuses on one specific degradation mechanism, namely the intergranular stress corrosion cracking (IGSCC). This is the major degradation mechanism in old stainless steel piping in BWR environment, and its growth is influenced by material properties, stresses and water chemistry. (au)

  2. Corrosion of Carbon Steel under Epoxy-varnish Coating Studied by Scanning Kelvin Probe

    Institute of Scientific and Technical Information of China (English)

    XIAO Kui; DONG Chaofang; ZHANG Xin; WU Junsheng; XU Longjiao; LI Xiaogang

    2012-01-01

    The corrosion behavior of partly coated carbon steel was investigated by salt spray test and scanning Kelvin probe (SKP) in order to understand the long-term corrosion behavior of coated carbon steel in marine atmosphere environment.The localized corrosion was accurately characterized by SKP in both coated and uncoated regions.The SKP results showed that Volta potential varied with the test time,and the more the corrosion products,the more positive the potential.The borderline between coated and uncoated regions of partly coated steel shifted towards the coated side with the increasing of test time.The coating disbonding rate could be determined according to the shift of potential borderline measured by SKP.The corrosion mechanism of partly coated steel in NaC1 salt spray was discussed according to the potential maps and corrosion morphologies.

  3. ELECTROCHEMICAL STUDIES ON THE CORROSION OF CARBON STEEL IN OXALIC ACID CLEANING SOLUTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B; John Mickalonis, J

    2007-10-08

    The Savannah River Site (SRS) will disperse or dissolve precipitated metal oxides as part of radioactive waste tank closure operations. Previously SRS has utilized oxalic acid to accomplish this task. Since the waste tanks are constructed of carbon steel, a significant amount of corrosion may occur. Although the total amount of corrosion may be insignificant for a short contact time, a significant amount of hydrogen may be generated due to the corrosion reaction. Linear polarization resistance and anodic/cathodic polarization tests were performed to investigate the corrosion behavior during the process. The effect of process variables such as temperature, agitation, aeration, sample orientation, light as well as surface finish on the corrosion behavior were evaluated. The results of the tests provided insight into the corrosion mechanism for the iron-oxalic acid system.

  4. A study of the corrosion products of mild steel in high ionic strength brines.

    Science.gov (United States)

    Wang, Z; Moore, R C; Felmy, A R; Mason, M J; Kukkadapu, R K

    2001-01-01

    The corrosion layer on steel surfaces that formed after exposure to waste isolation pilot plant (WIPP) brines under anoxic conditions was characterized for chemical composition, thickness and phase composition. The chemical composition of the corrosion layer was determined both by X-ray photoelectron spectroscopy (XPS) and by chemical analysis of acid solutions used to remove the corrosion layer. Atomic force microscopic (AFM) images indicated that the brine-corroded surface layer shows extensive granulation along the contours of the steel surface that is characteristic of sharp polishing marks. The corrosion layer seemed to be porous and could be dissolved and detached in dilute hydrochloric acid. The corrosion layer appears to be composed of iron oxides with some ionic substitutions from the brines. The 77 K Mössbauer spectrum recorded for iron powder leached under similar conditions indicated the corrosion layer was comprised principally of green rust.

  5. Hanford Double Shell Waste Tank Corrosion Studies - Final Report FY2015

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes, R. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Wyrwas, R. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-05-01

    During FY15, SRNL performed corrosion testing that supported Washington River Protection Solutions (WRPS) with their double shell tank (DST) integrity program. The testing investigated six concerns including, 1) the possibility of corrosion of the exterior of the secondary tank wall; 2) the effect of ammonia on vapor space corrosion (VSC) above waste simulants; 3) the determination of the minimum required nitrite and hydroxide concentrations that prevent pitting in concentrated nitrate solutions (i.e., waste buffering); 4) the susceptibility to liquid air interface (LAI) corrosion at proposed stress corrosion cracking (SCC) inhibitor concentrations; 5) the susceptibility of carbon steel to pitting in dilute solutions that contain significant quantities of chloride and sulfate; and 6) the effect of different heats of A537 carbon steel on the corrosion response. For task 1, 2, and 4, the effect of heat treating and/ or welding of the materials was also investigated.

  6. ELECTROCHEMICAL CORROSION STUDIES CORE 308 SEGMENTS 14R1 & 14R2 TANK 241-AY-102

    Energy Technology Data Exchange (ETDEWEB)

    DUNCAN JB; COOKE GA

    2003-10-30

    This document reports the results of electrochemical corrosion tests on AS1S Grade 60 carbon steel coupons exposed to tank 241-AY-102 sludge under conditions similar to those near the bottom of the tank. The tests were performed to evaluate the corrosive behavior of the waste in contact with sludge that does not meet the chemistry control limits of Administrative Control (AC) 5.15, Corrosion Mitigation Program.

  7. Study on H2S stress corrosion test of welded joint for X65 pipeline steel and numerical analysis

    Institute of Scientific and Technical Information of China (English)

    金晓军; 霍立兴; 张玉凤; 白秉仁; 李晓巍; 曹军

    2004-01-01

    The susceptibility of welded joint for the X65 pipeline steel to H2S stress corrosion cracking (SCC) is investigated. SCC tests on the steel are carried out in the environment based on NACE TM-01-77 solution with saturated gaseous H2S. The threshold stress intensity factor and crack propagation velocity are calculated according to wedge-opening loading (WOL) specimens. The three-dimensional elastic-plastic finite element analysis of WOL specimens is performed by using the FEM programming package ANSYS. Stress field and concentration of hydrogen distribution property ahead of the crack tip are obtained. This paper surveyed the microstructure of welded joint and studied on the mechanical properties of X65 pipeline steel. It provides experimental basis for studying stress corrosion. The results of numerical analysis are consistent with conclusions of stress corrosion test.

  8. A study of corrosion inhibition of steel AISI-SAE 1020 in CO2-brine using surfactant Tween 80

    Science.gov (United States)

    Cedeño, M. L.; L, E. Vera; Pineda T, Y.

    2017-01-01

    Surfactant inhibitors also called active surface agents are molecules composed of a polar hydrophilic group and a non-polar hydrophobic group, with characteristics of adsorption on metal surfaces, high efficiency of inhibiting, low price, low toxicity and easy production. In this work, the corrosion inhibition was study by CO2 steel AISI-SAE 1020 with the addition of 0.01M Tween 80 surfactant to a brine solution (3% NaCl). Electrochemical Impedance Spectroscopy and potentiodynamic polarization testing investigated the phenomenon. The results revealed that the surfactant studied acts as an excellent corrosion inhibitor and inhibition efficiency (E%) increases with increasing fluid velocity. The morphology of the steel surface after exposure to the solution of 3% NaCl with and without surfactant indicates the inhibition phenomenon is due to the adsorption of the surfactant molecules, which insulate the surface of the corrosive medium and reduces the attack surficial.

  9. Study on the Effects of Corrosion Inhibitor According to the Functional Groups for Cu Chemical Mechanical Polishing in Neutral Environment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Won; Kim, Jae Jeong [Institute of Chemical Process, Seoul National University, Seoul (Korea, Republic of)

    2015-08-15

    As the aluminum (Al) metallization process was replaced with copper (Cu), the damascene process was introduced, which required the planarization step to eliminate over-deposited Cu with Chemical Mechanical Polishing (CMP) process. In this study, the verification of the corrosion inhibitors, one of the Cu CMP slurry components, was conducted to find out the tendency regarding the carboxyl and amino functional group in neutral environment. Through the results of etch rate, removal rate, and chemical ability of corrosion inhibitors based on 1H-1,2,4-triazole as the base corrosion inhibitor, while the amine functional group presents high Cu etching ability, carboxyl functional group shows lower Cu etching ability than base-corrosion inhibitor which means that it increases passivation effect by making strong passivation layer. It implies that the corrosion inhibitor with amine functional group was proper to apply for 1st Cu CMP slurry owing to the high etch rate and with carboxyl functional group was favorable for the 2nd Cu CMP slurry due to the high Cu removal rate/dissolution rate ratio.

  10. Study of Acidithiobacillus ferrooxidans and enzymatic bio-Fenton process-mediated corrosion of copper-nickel alloy.

    Science.gov (United States)

    Jadhav, U; Hocheng, H

    2016-10-01

    This study presents the corrosion behavior of the copper-nickel (Cu-Ni) alloy in the presence of Acidithiobacillus ferrooxidans (A. ferrooxidans) and glucose oxidase (GOx) enzyme. In both the cases ferric ions played an important role in weight loss and thereby to carry out the corrosion of the Cu-Ni alloy. A corrosion rate of 0.6 (±0.008), 2.11 (±0.05), 3.69 (±0.26), 0.7 (±0.006) and 0.08 (±0.002) mm/year was obtained in 72 h using 9K medium with ferrous sulfate, A. ferrooxidans culture supernatant, A. ferrooxidans cells, GOx enzyme and hydrogen peroxide (H2O2) solution respectively. The scanning electron microscopy (SEM) micrographs showed that a variable extent of corrosion was caused by 9K medium with ferrous sulfate, GOx and A. ferrooxidans cells. An arithmetic average surface roughness (Ra) of 174.78 nm was observed for the control work-piece using optical profilometer. The change in Ra was observed with the treatment of the Cu-Ni alloy using various systems. The Ra for 9K medium with ferrous sulfate, GOx and A. ferrooxidans cells was 374.54, 607.32 and 799.48 nm, respectively, after 24 h. These results suggest that A. ferrooxidans cells were responsible for more corrosion of the Cu-Ni alloy than other systems used.

  11. Amino acids as corrosion inhibitors for copper in acidic medium: Experimental and theoretical study

    Directory of Open Access Journals (Sweden)

    Milošev Ingrid

    2013-01-01

    Full Text Available Experimental electrochemical methods combined with quantum chemical calculations and molecular dynamics simulations were used to investigate the possibility of use various amino acids as “green” corrosion inhibitors for copper in 0.5 M HCl solution. Among eleven amino acids studied, cysteine achieved the highest inhibitor effectiveness reaching 52% at 10 mM concentration. Other amino acids reached achieved effectiveness less than 25%, some of them even acted as corrosion accelerators. Based on the experimental results, theoretical calculations and simulations were focused on cysteine and alanine. The electronic and reactivity parameters of their protonated forms in electrical double layer were evaluated by density functional calculations. In addition, molecular dynamic simulations were introduced to follow the adsorption behaviour of these two amino acids at the Cu(111 surface in the electrolyte solution. The results indicate that the orientation of both molecules is nearly parallel to the surface except of ammonium group which is directed away from the surface. Therefore, as the orientation of the cysteine and alanine molecules at the surface is similar, thiol functional group is responsible for superior inhibition efficiency of cysteine.

  12. Management and control of microbiologically influenced corrosion (MIC) in the oil and gas industry-Overview and a North Sea case study.

    Science.gov (United States)

    Skovhus, Torben Lund; Eckert, Richard B; Rodrigues, Edgar

    2017-08-20

    the conflicting historic results obtained through serial dilution of culture media using the most probable number (MPN) method as compared to data obtained from corrosion monitoring and the quantitative polymerase chain reaction (qPCR) method. Results from qPCR application in the field case have changed the way MIC is monitored on the oil production facility in the North Sea. A number of high quality resources have been published as technical conference papers, books, educational videos and peer-reviewed scientific papers, and thus we end the review with an updated list of state-of-the-art resources for anyone desiring to become more familiar with the topic of MIC in the upstream oil and gas sector. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Corrosion protection

    Science.gov (United States)

    Brown, Donald W.; Wagh, Arun S.

    2003-05-27

    There has been invented a chemically bonded phosphate corrosion protection material and process for application of the corrosion protection material for corrosion prevention. A slurry of iron oxide and phosphoric acid is used to contact a warm surface of iron, steel or other metal to be treated. In the presence of ferrous ions from the iron, steel or other metal, the slurry reacts to form iron phosphates which form grains chemically bonded onto the surface of the steel.

  14. The coordinated use of synchrotron spectroelectrochemistry for corrosion studies on heritage metals.

    Science.gov (United States)

    Adriaens, Annemie; Dowsett, Mark

    2010-06-15

    Corrosion is a major source of degradation in heritage metal objects, and any remedial measures are subject to a strong (Western) ethic that favors conservation as opposed to restoration. Accordingly, major scientific challenges exist for developing appropriate treatment methods to stabilize and protect artifacts after they are recovered from an archaeological site, both before and during their display or storage in a museum. Because inappropriate treatments can cause irreversible damage to irreplaceable objects, it is crucial that the chemical processes involved are fully understood and characterized before any preservation work is undertaken. In this regard, large infrastructural facilities such as synchrotrons, neutron sources, and particle accelerators provide a wealth of analytical possibilities, unavailable in smaller scale laboratories. In general, the intensity of the radiation available allows measurements on a short time scale or with high spatial resolution (or both), so heterogeneous changes induced by a chemical process can be recorded while they occur. The penetrative nature of the radiation (e.g., X-rays, protons, or neutrons) also allows a sample to be studied in air. If necessary, complete artifacts (such as paintings or statuettes) can be examined. In situ analysis in a controlled environment, such as a liquid or corrosive atmosphere, also becomes an exciting possibility. Finally, there are many complementary techniques (local atomic structure or crystal structure determination, macroscopic 3-D imaging (tomographies), imaging chemical analysis, and so on) so the many distinct details of a problem can be thoroughly explored. In this Account, we discuss the application of this general philosophy to studies of corrosion and its prevention in cultural heritage metals, focusing on our recent work on copper alloys. More specifically, we use synchrotron-based techniques to evaluate the use of corrosion potential measurements as a possible monitoring

  15. Container assessment: corrosion study of HLW container materials. Quarterly progress report, July-September 1981. Volume 1, No. 3

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, T M; Soo, P

    1982-01-01

    Work has been started on the corrosion and hydrogen embrittlement behavior of commercially pure titanium (ASTM Grade 2), TiCode-12 (ASTM Grade 12), and OFHC copper, which are primary candidate materials for high level waste containers. The test environment used is a simulated brine solution typical of bedded salt at 150 C or room temperature. The immersion test results for these materials are in reasonable agreement with previous screening test results of Sandia National Laboratory; electron beam welded titanium and TiCode-12 samples show higher corrosion rates than the non-welded samples. To understand the difference between titanium and TiCode-12 in uniform and crevice corrosion, electrochemical tests were performed. While the initial repassivation behavior is similar in terms of charge density transfer after scratching tests in 1 M HCl solution at 80 C, titanium shows an active peak in polarization curves in brine at room temperature while TiCode-12 does not. Also, the open circuit corrosion potential of TiCode-12 is about 300 mV more anodic than that of titanium in 0.1 M HCl plus 0.9 M KCl solution at 85 C. Slow strain rate embrittlement and impact embrittlement have been observed in cathodically hydrogen charged commercially pure titanium and TiCode-12 in tension and buckling tests. C-ring and U-bend specimens of titanium and TiCode-12 have been designed and a slow strain rate test machine is being built to study stress corrosion cracking. Alternating Current Impedance and Scanning Reference Electrode Techniques are ready for pitting studies. For the study of radiation-induced corrosion, an irradiation cell was set up in the gamma pool to estimate quantitatively the oxidants as well as hydrogen produced by the gamma radiation in the brine solutions. 35 refs., 18 figs., 5 tabs.

  16. Application of electrochemical frequency modulation for monitoring corrosion and corrosion inhibition of iron by some indole derivatives in molar hydrochloric acid

    Energy Technology Data Exchange (ETDEWEB)

    Khaled, K.F. [Electrochemistry Research Laboratory, Chemistry Department, Faculty of Education, Ain Shams University, Roxy, Cairo (Egypt)], E-mail: khaled@asunet.shams.edu.eg

    2008-11-15

    The corrosion inhibition effect of four indole derivatives, namely indole (IND), benzotriazole (BTA), benzothiazole (BSA) and benzoimidazole (BIA), have been used as possible corrosion inhibitors for pure iron in 1 M HCl. In this study, electrochemical frequency modulation, EFM was used as an effective method for corrosion rate determination in corrosion inhibition studies. By using EFM measurements, corrosion current density was determined without prior knowledge of Tafel slopes. Corrosion rates obtained using EFM, were compared to that obtained from other chemical and electrochemical techniques. The results obtained from EFM, EIS, Tafel and weight loss measurements were in good agreement. Tafel polarization measurements show that indole derivatives are cathodic-type inhibitors. Molecular simulation studies were applied to optimize the adsorption structures of indole derivatives. The inhibitor/iron/solvent interfaces were simulated and the adsorption energies of these inhibitors were calculated. Quantum chemical calculations have been performed and several quantum chemical indices were calculated and correlated with the corresponding inhibition efficiencies.

  17. Study of the Corrosion of Reinforced Concrete%基于钢筋混凝土腐蚀的研究

    Institute of Scientific and Technical Information of China (English)

    谢振阳; 张智慧

    2014-01-01

    在混凝土中,最能影响其耐久性的因素就是钢筋的腐蚀。本文通过对某工程的钢筋混凝土结构腐蚀进行研究,介绍了钢筋混凝土结构的防腐问题,提出一系列切实可行的处理方法。%In concrete, corrosion is the main factor which affects its durability. This paper studies the corrosion of reinforced concrete structure of a certain project, introduces the problem of corrosion of reinforced concrete structure, and puts forward a series of feasible treatment method.

  18. In vivo electrochemical corrosion study of a CoCrMo biomedical alloy in human synovial fluids.

    Science.gov (United States)

    Igual Munoz, A; Schwiesau, J; Jolles, B M; Mischler, S

    2015-07-01

    The present study was initiated with the aim to assess the in vivo electrochemical corrosion behaviour of CoCrMo biomedical alloys in human synovial fluids in an attempt to identify possible patient or pathology specific effects. For this, electrochemical measurements (open circuit potential OCP, polarization resistance Rp, potentiodynamic polarization curves, electrochemical impedance spectroscopy EIS) were carried out on fluids extracted from patients with different articular pathologies and prosthesis revisions. Those electrochemical measurements could be carried out with outstanding precision and signal stability. The results show that the corrosion behaviour of CoCrMo alloy in synovial fluids not only depends on material reactivity but also on the specific reactions of synovial fluid components, most likely involving reactive oxygen species. In some patients the latter were found to determine the whole cathodic and anodic electrochemical response. Depending on patients, corrosion rates varied significantly between 50 and 750 mg dm(-2)year(-1).

  19. Influence of Heat Treatments on the Corrosion Resistance of Medium -Carbon Steel using Sulfuric Spring Water

    Directory of Open Access Journals (Sweden)

    Ikhlas Basheer

    2013-04-01

    Full Text Available The corrosion is one of the important problems that may be occur to the parts of machinery and equipment after manufactured and when used as a result of exposure to corrosive media. Plain-carbon steel is considered as one of the most common minerals used in industrial applications. Some of heat treatments can have direct effect on the corrosion rate of steel by building up galvanic corrosion cells between its microscopic phases. Therefore, to adopt one of kinds of the plain-carbon steel and the most commonly used in industry to be study subject, that is medium carbon steel and took samples of this steel has been treated thermally in three methods which the normalising, annealing, and hardening .The corrosive media used in the research is Sulfuric Spring, it contains many chemical compounds to show its influence on the corrosion of steel. The weight loss method is used to determine corrosion rate and to compare between the results obtained, show that the greatest corrosion resistance of the annealed steel and the corrosion resistance of the hardened steel is the lowest while the corrosion  resistance of the normalised steel is in-between them.         Calcium carbonate was formed on the metal surface which acts as an isolating layer which decrease corrosion rate with time

  20. Characterization of Encapsulated Corrosion Inhibitors Containing Microparticles for Environmentally Friendly Smart Coatings

    Science.gov (United States)

    Pearman, Benjamin Pieter; Calle, Luz M.

    2015-01-01

    This poster presents the results obtained from experiments designed to evaluate the release properties, as well as the corrosion inhibition effectiveness, of several encapsulated corrosion inhibitors. Microencapsulation has been used in the development of environmentally friendly multifunctional smart coatings. This technique enables the incorporation of autonomous corrosion detection, inhibition and self-healing functionalities into many commercially available coating systems. Select environmentally friendly corrosion inhibitors were encapsulated in organic and inorganic pH-sensitive microparticles and their release in basic solutions was studied. The release rate results showed that the encapsulation can be tailored from fast, for immediate corrosion protection, to slow, which will provide continued long-term corrosion protection. The incorporation of several corrosion inhibitor release profiles into a coating provides effective corrosion protection properties. To investigate the corrosion inhibition efficiency of the encapsulated inhibitors, electrochemical techniques were used to obtain corrosion potential, polarization curve and polarization resistance data. These measurements were performed using the free as well as the encapsulated inhibitors singly or in combinations. Results from these electrochemical tests will be compared to those obtained from weight loss and other accelerated corrosion experiments.

  1. Corrosion protection and control using nanomaterials

    CERN Document Server

    Cook, R

    2012-01-01

    This book covers the use of nanomaterials to prevent corrosion. The first section deals with the fundamentals of corrosion prevention using nanomaterials. Part two includes a series of case studies and applications of nanomaterials for corrosion control.$bCorrosion is an expensive and potentially dangerous problem in many industries. The potential application of different nanostructured materials in corrosion protection, prevention and control is a subject of increasing interest. Corrosion protection and control using nanomaterials explores the potential use of nanotechnology in corrosion control. The book is divided into two parts. Part one looks at the fundamentals of corrosion behaviour and the manufacture of nanocrystalline materials. Chapters discuss the impact of nanotechnology in reducing corrosion cost, and investigate the influence of various factors including thermodynamics, kinetics and grain size on the corrosion behaviour of nanocrystalline materials. There are also chapters on electrodeposition ...

  2. Electrochemical corrosion studies of carbon supports and electrocatalysts and their effects on the durability of low-temperature PEM fuel cells

    Science.gov (United States)

    Dowlapalli, Madhusudhana R.

    Performance of a PEM fuel cell relies heavily on the durability of the platinum and platinum-alloy based electrocatalysts supported on carbon blacks. Carbon corrosion has been widely accepted as an important issue affecting the degradation of the catalytic layer in PEMFCs. Traditional carbon blacks used in today's fuel cell industry are not tailored to suit the corrosive conditions encountered in PEMFCs. Advanced carbon supports should have excellent electrochemical corrosion resistance, good conductivity, high surface area and optimum hydrophilic properties. The principal objective of this work is to investigate the corrosive behavior of carbon blacks and electrocatalysts supported on such carbon blacks in conditions that are typical for fuel cells. Physical and chemical changes during oxidation of these carbon blacks have been reviewed along with methodology for studying their corrosion in a low-temperature fuel cell environment. This study provides an ex-situ corrosion measurement protocol and a gas diffusion electrode half-cell setup to study the electrochemical oxidation resistance behavior of standard carbon blacks, modified carbon blacks, and advanced carbon supports in acid electrolyte at 25°C. Corrosion current-time relationships were evaluated and transient mode of corrosion study was employed to simulate automobile startup/shutdown. The effects of various surface modifications on carbon corrosion behavior have been studied in detail. The aggravated corrosion of carbon supports at potentials higher than the thermodynamic stable regime of water was investigated and a mechanism is proposed to address the same. The role of the metal phase on carbon corrosion at the catalyst-support interphase has also been investigated. The corrosion current dependence on the microstructure and nature of surface groups present on these carbons was examined. Further, measuring carbon corrosion effects on the durability of a single membrane-electrode assembly (MEA) cathode

  3. Alkali chloride induced corrosion of superheaters under biomass firing conditions: Improved insights from laboratory scale studies

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Montgomery, Melanie; Jappe Frandsen, Flemming

    2015-01-01

    to the formation of corrosive deposits (rich in alkali chlorides) on the surfaces of the superheaters. Accordingly, an extensive number of fundamental investigations have been undertaken to understand the basic mechanisms behind the alkali chloride induced high temperature corrosion of superheaters (for example...

  4. Electrochemical, Polarization, and Crevice Corrosion Testing of Nitinol 60, A Supplement to the ECLSS Sustaining Materials Compatibility Study

    Science.gov (United States)

    Lee, R. E.

    2016-01-01

    In earlier trials, electrochemical test results were presented for six noble metals evaluated in test solutions representative of waste liquids processed in the Environmental Control and Life Support System (ECLSS) aboard the International Space Station (ISS). Subsequently, a seventh metal, Nitinol 60, was added for evaluation and subjected to the same test routines, data analysis, and theoretical methodologies. The previous six test metals included three titanium grades, (commercially pure, 6Al-4V alloy and 6Al-4V low interstitial alloy), two nickel-chromium alloys (Inconel(RegisteredTrademark) 625 and Hastelloy(RegisteredTrademark) C276), and one high-tier stainless steel (Cronidur(RegisteredTrademark) 30). The three titanium alloys gave the best results of all the metals, indicating superior corrosive nobility and galvanic protection properties. For this current effort, the results have clearly shown that Nitinol 60 is almost as noble as titanium, being very corrosion-resistant and galvanically compatible with the other six metals electrochemically and during long-term exposure. is also quite noble as it is very corrosion resistant and galvanically compatible with the other six metals from both an electrochemical perspective and long-term crevice corrosion scenario. This was clearly demonstrated utilizing the same techniques for linear, Tafel and cyclic polarization, and galvanic coupling of the metal candidate as was done for the previous study. The high nobility and low corrosion susceptibility for Nitinol 60 appear to be intermediate to the nickel/chromium alloys and the titanium metals with indications that are more reflective of the titanium metals in terms of general corrosion and pitting behavior.

  5. A photoemission study of the effectiveness of nickel, manganese, and cobalt based corrosion barriers for silicon photo-anodes during water oxidation

    Science.gov (United States)

    O'Connor, Robert; Bogan, Justin; McCoy, Anthony; Byrne, Conor; Hughes, Greg

    2016-05-01

    Silicon is an attractive material for solar water splitting applications due to its abundance and its capacity to absorb a large fraction of incident solar radiation. However, it has not received as much attention as other materials due to its tendency to oxidize very quickly in aqueous environments, particularly when it is employed as the anode where it drives the oxygen evolution reaction. In recent years, several works have appeared in the literature examining the suitability of thin transition metal oxide films grown on top of the silicon to act as a corrosion barrier. The film should be transparent to solar radiation, allow hole transport from the silicon surface to the electrolyte, and stop the diffusion of oxygen from the electrolyte back to the silicon. In this work, we compare Mn-oxide, Co-oxide, and Ni-oxide thin films grown using physical vapor deposition in order to evaluate which material offers the best combination of photocurrent and corrosion protection. In addition to the electrochemical data, we also present a detailed before-and-after study of the surface chemistry of the films using x-ray photoelectron spectroscopy. This approach allows for a comprehensive analysis of the mechanisms by which the corrosion barriers protect the underlying silicon, and how they degrade during the water oxidation reaction.

  6. Applicability of in vitro tests for skin irritation and corrosion to regulatory classification schemes: substantiating test strategies with data from routine studies.

    Science.gov (United States)

    Kolle, Susanne N; Sullivan, Kristie M; Mehling, Annette; van Ravenzwaay, Bennard; Landsiedel, Robert

    2012-12-01

    Skin corrosion or irritation refers to the production of irreversible or reversible damage to the skin following the application of a test substance, respectively. Traditionally, hazard assessments are conducted using the in vivo Draize skin test, but recently in vitro tests using reconstructed human epidermis (RhE) models have gained regulatory acceptance. In this study, skin corrosion (SCT) and irritation tests (SIT) using a RhE model were implemented to reduce the number of in vivo tests required by regulatory bodies. One hundred and thirty-four materials were tested from a wide range of substance classes included 46 agrochemical formulations. Results were assessed according to UN GHS, EU-CLP, ANVISA and US EPA classification schemes. There was high correlation between the two in vitro tests. Assessment of the SCT sensitivity was not possible due to the limited number of corrosives in the data set; SCT specificity and accuracy were 89% for all classification systems. Accuracy (63-76%) and sensitivity (53-67%) were low in the SIT. Specificity and concordance for agrochemical formulations alone in both the SCT and SIT were comparable to the values for the complete data set (SCT: 91% vs. 89% specificity, 91% vs. 89% accuracy and SIT: 64-88% vs. 70-85% specificity, 56-75% vs. 63-76% accuracy).

  7. Preliminary study for extension and improvement on modeling of primary water stress corrosion cracking at control rod drive mechanism nozzles of pressurized water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Aly, Omar F.; Mattar Neto, Miguel M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)], e-mail: ofaly@ipen.br, e-mail: mmattar@ipen.br; Schvartzman, Monica M.M.A.M. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil)], e-mail: monicas@cdtn.br

    2009-07-01

    This study is for to extend, to improve the existing models, and to propose a local approach to assess the primary water stress corrosion cracking in nickel-based components. It is includes a modeling of new data for Alloy 182 and new considerations about initiation and crack growth according a developing method based on EPRI-MRP-115 (2004), and USNRC NUREG/CR-6964 (2008). The experimental data is obtained from CDTN-Brazilian Nuclear Technology Development Center, by tests through slow strain rate test (SSRT) equipment. The model conception assumed is a built diagram which indicates a thermodynamic condition for the occurrence of corrosion submodes in essayed materials, through Pourbaix diagrams, for Nickel Alloys in high temperature primary water. Over them, are superimposed different models, including a semi-empiric-probabilistic one to quantify the primary water stress corrosion cracking susceptibility, and a crack growth model. These constructed models shall be validated with the experimental data. This development aims to extent some of the models obtained to weld metals like the Alloy 182, and to improve the originals obtained according methodologies exposed in above referred reports. These methodologies comprise laboratory testing procedures, data collecting, data screening, modeling procedures, assembling of data from some laboratories in the world, plotting of results, compared analysis and discussion of these results. Preliminary results for Alloy 182 will be presented. (author)

  8. Results from a Novel Method for Corrosion Studies of Electroplated Lithium Metal Based on Measurements with an Impedance Scanning Electrochemical Quartz Crystal Microbalance

    Directory of Open Access Journals (Sweden)

    Martin Winter

    2013-07-01

    Full Text Available A new approach to study the chemical stability of electrodeposited lithium on a copper metal substrate via measurements with a fast impedance scanning electrochemical quartz crystal microbalance is presented. The corrosion of electrochemically deposited lithium was compared in two different electrolytes, based on lithium difluoro(oxalato borate (LiDFOB and lithium hexafluorophosphate, both salts being dissolved in solvent blends of ethylene carbonate and diethyl carbonate. For a better understanding of the corrosion mechanisms, scanning electron microscopy images of electrodeposited lithium were also consulted. The results of the EQCM experiments were supported by AC impedance measurements and clearly showed two different corrosion mechanisms caused by the different salts and the formed SEIs. The observed mass decrease of the quartz sensor of the LiDFOB-based electrolyte is not smooth, but rather composed of a series of abrupt mass fluctuations in contrast to that of the lithium hexafluorophosphate-based electrolyte. After each slow decrease of mass a rather fast increase of mass is observed several times. The slow mass decrease can be attributed to a consolidation process of the SEI or to the partial dissolution of the SEI leaving finally lithium metal unprotected so that a fast film formation sets in entailing the observed fast mass increases.

  9. Corrosion sensor

    Science.gov (United States)

    Glass, Robert S.; Clarke, Jr., Willis L.; Ciarlo, Dino R.

    1994-01-01

    A corrosion sensor array incorporating individual elements for measuring various elements and ions, such as chloride, sulfide, copper, hydrogen (pH), etc. and elements for evaluating the instantaneous corrosion properties of structural materials. The exact combination and number of elements measured or monitored would depend upon the environmental conditions and materials used which are subject to corrosive effects. Such a corrosion monitoring system embedded in or mounted on a structure exposed to the environment would serve as an early warning system for the onset of severe corrosion problems for the structure, thus providing a safety factor as well as economic factors. The sensor array is accessed to an electronics/computational system, which provides a means for data collection and analysis.

  10. Review of state-of-the-art of solar collector corrosion processes. Task 1 of solar collector studies for solar heating and cooling applications. Final technical progress report

    Energy Technology Data Exchange (ETDEWEB)

    Clifford, J E; Diegle, R B

    1980-04-11

    The state-of-the-art of solar collector corrosion processes is reviewed, and Task 1 of a current research program on use of aqueous heat transfer fluids for solar heating and cooling is summarized. The review of available published literature has indicated that lack of quantitative information exists relative to collector corrosion at the present time, particularly for the higher temperature applications of solar heating and cooling compared to domestic water heating. Solar collector systems are reviewed from the corrosion/service life viewpoint, with emphasis on various applications, collector design, heat transfer fluids, and freeze protection methods. Available information (mostly qualitative) on collector corrosion technology is reviewed to indicate potential corrosion problem areas and corrosion prevention practices. Sources of limited quantitative data that are reviewed are current solar applications, research programs on collector corrosion, and pertinent experience in related applications of automotive cooling and non-solar heating and cooling. A data bank was developed to catalog corrosion information. Appendix A of this report is a bibliography of the data bank, with abstracts reproduced from presently available literature accessions (about 220). This report is presented as a descriptive summary of information that is contained in the data bank.

  11. Marine corrosion of mild steel at Lumut, Perak

    Science.gov (United States)

    Ting, Ong Shiou; Potty, Narayanan Sambu; Liew, Mohd. Shahir

    2012-09-01

    The corrosion rate of structural steels in the adverse marine and offshore environments affects the economic interest of offshore structures since the loss of steel may have significant impact on structural safety and performance. With more emphasis to maintain existing structures in service for longer time and hence to defer replacement costs, there is increasing interest in predicting corrosion rate at a given location for a given period of exposure once the protection coating or cathodic protection is lost. The immersion depth, salinity, steel composition and water pollution will be taken into account. Various corrosion allowances are prescribed for structural members by different standards. There are no studies to determine the appropriate corrosion allowance for steel structures in marine environment in Malaysia. The objectives of the research are to determine the nature and rate of corrosion in mm/year for steel structures in marine environment. It also tries to identify whether the corrosion rate is affected by differences in the chemical composition of the steels, and microalgae. Two sets of corrosion coupons of Type 3 Steel consisting of mild steel were fabricated and immersed in seawater using steel frames. The corrosion rate of the coupon in mm/ per year is estimated based on the material weight loss with time in service. The results are compared with recommendations of the code.

  12. Stress Corrosion Cracking and Fatigue Crack Growth Studies Pertinent to Spacecraft and Booster Pressure Vessels

    Science.gov (United States)

    Hall, L. R.; Finger, R. W.

    1972-01-01

    This experimental program was divided into two parts. The first part evaluated stress corrosion cracking in 2219-T87 aluminum and 5Al-2.5Sn (ELI) titanium alloy plate and weld metal. Both uniform height double cantilever beam and surface flawed specimens were tested in environments normally encountered during the fabrication and operation of pressure vessels in spacecraft and booster systems. The second part studied compatibility of material-environment combinations suitable for high energy upper stage propulsion systems. Surface flawed specimens having thicknesses representative of minimum gage fuel and oxidizer tanks were tested. Titanium alloys 5Al-2.5Sn (ELI), 6Al-4V annealed, and 6Al-4V STA were tested in both liquid and gaseous methane. Aluminum alloy 2219 in the T87 and T6E46 condition was tested in fluorine, a fluorine-oxygen mixture, and methane. Results were evaluated using modified linear elastic fracture mechanics parameters.

  13. Evaluation of biological stability and corrosion potential in drinking water distribution systems: a case study.

    Science.gov (United States)

    Chien, C C; Kao, C M; Chen, C W; Dong, C D; Chien, H Y

    2009-06-01

    The appearance of assimilable organic carbon (AOC), microbial regrowth, disinfection by-products (DBPs), and pipe corrosion in drinking water distribution systems are among those major safe drinking water issues in many countries. The water distribution system of Cheng-Ching Lake Water Treatment Plant (CCLWTP) was selected in this study to evaluate the: (1) fate and transport of AOC, DBPs [e.g., trihalomethanes (THMs), haloacetic acids (HAAs)], and other organic carbon indicators in the selected distribution system, (2) correlations between AOC (or DBPs) and major water quality parameters [e.g. dissolved oxygen (DO), free residual chlorine, and bacteria, and (3) causes and significance of corrosion problems of the water pipes in this system. In this study, seasonal water samples were collected from 13 representative locations in the distribution system for analyses of AOC, DBPs, and other water quality indicators. Results indicate that residual free chlorine concentrations in the distribution system met the drinking water standards (0.2 to 1 mg l(-1)) established by Taiwan Environmental Protection Administration (TEPA). Results show that AOC measurements correlated positively with total organic carbon (TOC) and UV-254 (an organic indicator) values in this system. Moreover, AOC concentrations at some locations were higher than the 50 microg acetate-C l(-1) standard established by Taiwan Water Company. This indicates that the microbial regrowth might be a potential water quality problem in this system. Higher DO measurements (>5.7 mg l(-1)) might cause the aerobic biodegradation of THMs and HAAs in the system, and thus, low THMs (water distribution system for maintaining a safe drinking water quality.

  14. Atmospheric corrosion in subtropical areas: XRD and electrochemical study of zinc atmospheric corrosion products in the province of Santa Cruz de Tenerife (Canary Islands, Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Morales, J. [Departamento de Quimica Fisica, Universidad de La Laguna, 38071 La Laguna, Tenerife (Spain)]. E-mail: jmorales@ull.es; Diaz, F. [Departamento de Quimica Fisica, Universidad de La Laguna, 38071 La Laguna, Tenerife (Spain); Hernandez-Borges, J. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Universidad de La Laguna, 38071 La Laguna, Tenerife (Spain); Gonzalez, S. [Departamento de Quimica Fisica, Universidad de La Laguna, 38071 La Laguna, Tenerife (Spain)

    2006-02-15

    In the present paper, zinc sheets have been exposed for 4 years to the action of different atmospheres in 35 test sites located in the province of Santa Cruz de Tenerife, Canary Islands, Spain. Corrosion products formed on the surface of the samples have been identified by means of X-ray diffraction (XRD) for the first and second year of exposure. Zincite, hydrozincite, simonkolleite, zinc chlorohydroxysulphate, zinc oxysulphate and zinc hydroxysulphate have been identified in the test sheets. Preliminary results of an electrochemical study of the breakdown potential of zinc samples are also presented in order to test the protective effect of the film formed on the surface of the samples. It was found that the protective effect of this film increases linearly with exposure time.

  15. Kinetics of Atmospheric Corrosion of Mild Steel in Marine and Rural Environments

    Institute of Scientific and Technical Information of China (English)

    S. Palraj; M.Selvaraj; K.Maruthan; M.Natesan

    2015-01-01

    In continuation of the extensive studies carried out to update the corrosion map of India, in this study, the degradation of mild steel by air pollutants was studied at 16 different locations from Nagore to Ammanichatram along the east coast of Tamilnadu, India over a period of two years. The weight loss study showed that the mild steel corrosion was more at Nagapattinam site, when compared to Ammanichatram and Maravakadu sites. A linear regression analysis of the experimental data was attempted to predict the mechanism of the corrosion. The composition of the corrosion products formed on the mild steel surfaces was identified by XRD technique. The corrosion rate values obtained are discussed in the light of the weathering parameters, atmospheric pollutants such as salt content & SO2 levels in the atmosphere, corrosion products formed on the mild steel surfaces.

  16. Monitoring corrosion and corrosion control of iron in HCl by non-ionic surfactants of the TRITON-X series - Part III. Immersion time effects and theoretical studies

    Energy Technology Data Exchange (ETDEWEB)

    Amin, Mohammed A., E-mail: maaismail@yahoo.co [Materials and Corrosion Lab (MCL), Department of Chemistry, Faculty of Science, Taif University, 888 Hawaiya, Taif (Saudi Arabia); Department of Chemistry, Faculty of Science, Ain Shams University, 11566 Abbassia, Cairo (Egypt); Ahmed, M.A. [Physics Department, Faculty of Science, Taif University, 888 Hawaiya, Taif (Saudi Arabia); Arida, H.A. [Materials and Corrosion Lab (MCL), Department of Chemistry, Faculty of Science, Taif University, 888 Hawaiya, Taif (Saudi Arabia); Kandemirli, Fatma [Nigde University, Department of Chemistry, 51240 Nigde (Turkey); Saracoglu, Murat [Faculty of Education, Erciyes University, 38039 Kayseri (Turkey); Arslan, Taner [Department of Chemistry, Eskisehir Osmangazi University, 26480 Eskisehir (Turkey); Basaran, Murat A. [Nigde University, Department of Mathematics, 51240 Nigde (Turkey)

    2011-05-15

    Graphical abstract: . Display Omitted Research highlights: The inhibition effect of TX-100, TX-165 and TX-305 on iron corrosion in 1.0 M HCl was studied. TX-305 inhibited iron corrosion more effectively than TX-100 and TX-165. In most cases, inhibition efficiency increased with time during the first 60 min of immersion, then decreased. Calculated quantum chemical parameters confirmed the experimental inhibition efficiencies of the tested surfactants. - Abstract: The inhibition performance of three selected non-ionic surfactants of the TRITON-X series, namely TRITONX-100 (TX-100), TRITON-X-165 (TX-165) and TRITON-X-305 (TX-305), on the corrosion of iron was studied in 1.0 M HCl solutions as a function of inhibitor concentration (0.01-0.20 g L{sup -1}) and immersion time (0.0-8 h) at 298 K. Measurements were conducted based on Tafel polarization, LPR and impedance studies. At high frequencies, the impedance spectrum showed a depressed capacitive loop in the complex impedance plane, whose diameter is a function of the immersion time and the type and concentration of the introduced surfactant. In all cases, an inductive loop was observed in the low frequency and this could be attributed to the adsorption behavior. The inhibition efficiency increased with immersion time, reached a maximum and then decreased. This was attributed to the orientation change of adsorbed surfactant molecules. TX-305 inhibited iron corrosion more effectively than TX-100 and TX-165. The frontier orbital energies, the energy gap between frontier orbitals, dipole moments ({mu}), charges on the C and O atoms, the polarizabilities, and the quantum chemical descriptors were calculated. The quantum chemical calculation results inferred that for the HOMO representing the condensed Fukui function for an electrophilic attack (f{sub k}{sup +}), the contributions belong to the phenyl group and the oxygen atom attached to the phenyl group for each tested surfactant. Quantitative structure

  17. Biofuel: a comparative case study

    OpenAIRE

    Siddiqui, Aamir; Kading, Christopher; Carter, Kasey

    2013-01-01

    Approved for public release; distribution is unlimited This project analyzes the governments role in the commercialization of biofuel by comparing biofuel commercialization efforts to those of nuclear power and nanotechnology commercialization. The PESTEL framework is applied to nuclear power and nanotechnology to identify key factors relevant to successful commercialization. These success factors are compared to current government biofuel policies to infer the likelihood of successful bio...

  18. Quantitative measures of corrosion and prevention: application to corrosion in agriculture

    NARCIS (Netherlands)

    Schouten, J.C.; Gellings, P.J.

    1987-01-01

    The corrosion protection factor (c.p.f.) and the corrosion condition (c.c.) are simple instruments for the study and evaluation of the contribution and efficiency of several methods of corrosion prevention and control. The application of c.p.f. and c.c. to corrosion and prevention in agriculture in

  19. Quantitative measures of corrosion and prevention: application to corrosion in agriculture

    NARCIS (Netherlands)

    Schouten, J.C.; Gellings, P.J.

    1987-01-01

    The corrosion protection factor (c.p.f.) and the corrosion condition (c.c.) are simple instruments for the study and evaluation of the contribution and efficiency of several methods of corrosion prevention and control. The application of c.p.f. and c.c. to corrosion and prevention in agriculture in

  20. A Positron Annihilation Study of Corrosion of Aluminum and Aluminum Alloy by NaOH

    Science.gov (United States)

    Wu, Y. C.; Zhai, T.; Coleman, P. G.

    2012-08-01

    Corrosion of fully-annealed pure aluminum and a continuous-cast AA2037 aluminum alloy (solutionized and water quenched) in a 1M NaOH solution for various periods of time were analyzed with positron beam-based Doppler broadening spectroscopy. By varying the energy of the incident positron beam, corrosion-induced defects at different depths from the surface were detected. It was found that the Doppler-broadened annihilation line-width parameter was significantly increased near the surface of pure aluminum after corrosion, probably due to the interaction between positrons and nanometer-sized voids formed near the aluminum surface during corrosion. Examination by atomic force microscopy indicated that many pits were formed on the aluminum surface after corrosion. In contrast, a significant decrease in the line-width parameter was observed in AA2037 alloy after corrosion and interpreted as being caused by copper enrichment at the metal-oxide interface during corrosion; such enrichment at large cavity sites was confirmed by energy dispersion spectrometry.

  1. An Experimental Study for Quantitative Estimation of Rebar Corrosion in Concrete Using Ground Penetrating Radar

    Directory of Open Access Journals (Sweden)

    Md Istiaque Hasan

    2016-01-01

    Full Text Available Corrosion of steel rebar in reinforced concrete is one the most important durability issues in the service life of a structure. In this paper, an investigation is conducted to find out the relationship between the amount of reinforced concrete corrosion and GPR maximum positive amplitude. Accelerated corrosion was simulated in the lab by impressing direct current into steel rebar that was submerged in a 5% salt water solution. The amount of corrosion was varied in the rebars with different levels of mass loss ranging from 0% to 45%. The corroded rebars were then placed into three different oil emulsion tanks having different dielectric properties similar to concrete. The maximum amplitudes from the corroded bars were recorded. A linear relationship between the maximum positive amplitudes and the amount of corrosion in terms of percentage loss of area was observed. It was proposed that the relationship between the GPR maximum amplitude and the amount of corrosion can be used as a basis of a NDE technique of quantitative estimation of corrosion.

  2. Corrosion behavior of Ti-39Nb alloy for dentistry.

    Science.gov (United States)

    Fojt, Jaroslav; Joska, Ludek; Malek, Jaroslav; Sefl, Vaclav

    2015-11-01

    To increase an orthopedic implant's lifetime, researchers are now concerned on the development of new titanium alloys with suitable mechanical properties (low elastic modulus-high fatigue strength), corrosion resistance and good workability. Corrosion resistance of the newly developed titanium alloys should be comparable with that of pure titanium. The effect of medical preparations containing fluoride ions represents a specific problem related to the use of titanium based materials in dentistry. The aim of this study was to determine the corrosion behavior of β titanium alloy Ti-39Nb in physiological saline solution and in physiological solution containing fluoride ions. Corrosion behavior was studied using standard electrochemical techniques and X-ray photoelectron spectroscopy. It was found that corrosion properties of the studied alloy were comparable with the properties of titanium grade 2. The passive layer was based on the oxides of titanium and niobium in several oxidation states. Alloying with niobium, which was the important part of the alloy passive layer, resulted in no significant changes of corrosion behavior. In the presence of fluoride ions, the corrosion resistance was higher than the resistance of titanium.

  3. Study of benzotriazole as corrosion inhibitors of carbon steel in chloride solution containing hydrogen sulfide using electrochemical impedance spectroscopy (EIS)

    Energy Technology Data Exchange (ETDEWEB)

    Solehudin, Agus, E-mail: asolehudin@upi.edu [Department of Mechanical Engineering Education, Indonesia University of Education (UPI), Bandung, West Java (Indonesia); Nurdin, Isdiriayani [Department of Chemical Engineering, Bandung Institute of Technology, Bandung, West Java (Indonesia)

    2014-03-24

    Corrosion and inhibition studies on API 5LX65 carbon steel in chloride solution containing various concentrations of benzotriazole has been conducted at temperature of 70°C using Electrochemical Impedance Spectroscopy (EIS). Corroded carbon steel surface with and without inhibitor have been observed using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive Spectroscopy (EDS). The objectives of this research are to study the performance of benzotriazole as corrosion inhibitors. The experimental results of carbon steel corrosion in 3.5% NaCl solution containing 500 mg/l H{sub 2}S at different BTAH concentrations showed that corrosion rate of carbon steel decreases with increasing of BTAH concentrations from 0 to 10 mmol/l. The inhibition efficiency of BTAH was found to be affected by its concentration. The optimum efficiency obtained of BTAH is 93% at concentration of 5 mmol/l. The result of XRD and EDS analysis reveal the iron sulfide (FeS) formation on corroded carbon steel surface without inhibitor. The EDS spectrum show the Nitrogen (N) bond on carbon steel surface inhibited by BTAH.

  4. Study of benzotriazole as corrosion inhibitors of carbon steel in chloride solution containing hydrogen sulfide using electrochemical impedance spectroscopy (EIS)

    Science.gov (United States)

    Solehudin, Agus; Nurdin, Isdiriayani

    2014-03-01

    Corrosion and inhibition studies on API 5LX65 carbon steel in chloride solution containing various concentrations of benzotriazole has been conducted at temperature of 70°C using Electrochemical Impedance Spectroscopy (EIS). Corroded carbon steel surface with and without inhibitor have been observed using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive Spectroscopy (EDS). The objectives of this research are to study the performance of benzotriazole as corrosion inhibitors. The experimental results of carbon steel corrosion in 3.5% NaCl solution containing 500 mg/l H2S at different BTAH concentrations showed that corrosion rate of carbon steel decreases with increasing of BTAH concentrations from 0 to 10 mmol/l. The inhibition efficiency of BTAH was found to be affected by its concentration. The optimum efficiency obtained of BTAH is 93% at concentration of 5 mmol/l. The result of XRD and EDS analysis reveal the iron sulfide (FeS) formation on corroded carbon steel surface without inhibitor. The EDS spectrum show the Nitrogen (N) bond on carbon steel surface inhibited by BTAH.

  5. Studies of corrosion properties and hydrogen embrittlement in laser welding of Zry-4; Estudio de las propiedades a la corrosion y a la frazilizacion por hidrogeno en soldaduras laser de zircaloy-4

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Luis; Meyer, Gabriel; Corso, Hugo [Centro Atomico Bariloche, San Carlos de Bariloche (Argentina); Martinez, Roberto [Invap S.E., San Carlos de Bariloche (Argentina)

    1996-07-01

    This paper compares the preliminary results obtained from welding of Zircaloy-4 performed by TIG technique with the results obtained using laser welding of CO{sub 2} of 1500W and pulsed beams of Nd:YAG of 332W and 350W, aiming an eventual application to fuel element fabrication. The comparison between the results have proved that there exist no damage in the corrosion resistance properties and sensitivity to hydrogen embrittlement when the usual TIG technique have been replaced for laser welding techniques. A study about the possible diffusion of iron and tin using dispersive x-ray spectroscopy and SEM in heat affected zone produced by welding have also been presented.

  6. Studies on corrosion protection of laser hybrid welded AISI 316 by laser remelting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Ambat, Rajan; Rasmussen, A.J.

    2005-01-01

    laser surface melting on microstructure and corrosion behaviour of AISI 316L welds. Welding and laser treatment parameters were varied. General corrosion behaviour of the weld and laser treated surface was characterised using a gel visualization test. The local electrochemistry of the weld and laser...... treated surface was investigated using a novel micro electrochemical technique with a tip resolution of ~1 mm. Results show that hybrid laser welding of 316L has increased corrosion susceptibility probably as a result of grain boundary carbide formation. However a suitable post laser treatment could...

  7. An Electrochemical Study on the Corrosion Inhibition of Stainless Steel by Polyaniline Film

    Institute of Scientific and Technical Information of China (English)

    Hao WANG; Lin NIU; Qiu Hong LI; Su Xiang WU; Feng Hua WEI

    2004-01-01

    Polyaniline(PANI) film was electrosynthesized on 304 stainless steel by cyclic voltammetry using aqueous oxalic acid as supporting electrolyte. The potential sweep rates were changed to achieve the PANI film with different thickness and structures. Protective properties of the PANI film for corrosion of stainless steel in 3% NaCl aqueous solution were investigated by monitoring potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS).The results showed that the PANI film which was formed with lower sweep rate led to more positive shift of corrosion potential and greater charge transfer resistance, reflecting higher inhibition for corrosion of the stainless steel.

  8. Acoustic emission in wet or dry corrosion studies: an update on the art and usefulness of a data base; L'emission acoustique en corrosion humide et seche: etat de l'art et interet d'une base de donnees

    Energy Technology Data Exchange (ETDEWEB)

    Caron, D.; Rigault, C. [Cetim-Centre Technique des Industries Mecaniques, 30 - Senlis (France); Rothea, C.; Mazille, H. [Institut National des Sciences Appliquees, INSA, 69 - Villeurbanne (France); Gaillet, L.; Moulin, G.; Beranger, G. [Universite de Technologie de Compiegne, 60 (France)

    2001-07-01

    At the initiative of CETIM, a bibliographical work was accomplished at the LPCI (INSA Lyon) and UTC. The aim of this work was to establish the most current and complete state of the art on the potential of the acoustic emission (A.E.) for the detection of wet or dry corrosion met on many equipments used in the mechanical, chemical and petrochemical industries. Corrosion can affect all metallic equipments of industry under more or less aggressive operating conditions. In spite of the existing knowledge of the degradation mechanisms, the post-mortem analysis or laboratory simulation only gives either late or incomplete information. This usually results from difficulties to determine the actual local conditions. A.E. is a non-destructive control technique that can be applied as well in laboratory as on industrial site. According to literature data, the ability of A.E. to detect and monitor wet or dry corrosion was evidenced. Thus, it could be used for to a more reliable, secure and economic industrial management. However A.E. was and is still sometimes discussed. Indeed, the diversity of the equipments, processes and conditions of exploitation can generate some discrepancies. This study attempts to remove these ambiguities by detailing the principal parameters and key factors in order to objectively compare the referenced works. Our works confirms that A.E. is a very sensitive and powerful technique for studying wet or dry corrosion in laboratories or on industrial plants. (authors)

  9. Migrating corrosion inhibitor protection of concrete

    Energy Technology Data Exchange (ETDEWEB)

    Bjegovic, D.; Miksic, B.

    1999-11-01

    Migrating corrosion inhibitors (MCI) were developed to protect steel rebar from corrosion in concrete. They were designed to be incorporated as an admixture during concrete batching or used for surface impregnation of existing concrete structures. Two investigations are summarized. One studied the effectiveness of MCIs as a corrosion inhibitor for steel rebar when used as an admixture in fresh concrete mix. The other is a long-term study of MCI concrete impregnation that chronicles corrosion rates of rebar in concrete specimens. Based on data from each study, it was concluded that migrating corrosion inhibitors are compatible with concrete and effectively delay the onset of corrosion.

  10. Effect on aluminum corrosion of LiBF{sub 4} addition into lithium imide electrolyte; a study using the EQCM

    Energy Technology Data Exchange (ETDEWEB)

    Song, Seung-Wan; Richardson, Thomas J.; Zhuang, Guorong V.; Devine, Thomas M.; Evans, James W

    2004-04-15

    A study of the corrosion of Al, used as a current collector for the cathode of rechargeable lithium batteries, has been carried out using the electrochemical quartz crystal microbalance (EQCM). An aluminum film was highly corroded in 1 M LiTFSI (lithium trifluorosulfonimide (LiTFSI), LiN(SO{sub 2}CF{sub 3}){sub 2})/EC+DMC electrolyte at 2-5 V versus Li/Li{sup +} with the formation of large pits, while the corrosion was clearly suppressed by adding LiBF{sub 4} salt into the imide electrolyte. Depression of corrosion on adding LiBF{sub 4} was attributed to the formation of a stable passive layer on the surface of aluminum due to the reaction of aluminum with electrolyte and the decomposition of electrolyte solvent at high potentials. The resulting data may help clarify the corrosion mechanism of aluminum metal in imide electrolyte and give insight into enhancing the performance of lithium ion batteries.

  11. Experimental and computational studies of Nicotiana tabacum leaves extract as green corrosion inhibitor for mild steel in acidic medium

    Directory of Open Access Journals (Sweden)

    Jeetendra Bhawsar

    2015-09-01

    Full Text Available In the present work corrosion inhibition of mild steel in 2 M H2SO4 solution by Nicotiana tabacum extract was studied by weight loss method. It has been found that the extract acts as an effective corrosion inhibitor for mild steel in Sulfuric acid medium. The inhibition process is attributed to the formation of an adsorbed film of inhibitor on the metal surface which protects the metal against corrosion. The inhibition efficiency (%IE and surface coverage (θ of N. tabacum extract increased with increase in inhibitor concentration but decreased with increasing the temperature. The adsorption of extract on the mild steel surface was found to obey Langmuir’s adsorption isotherm. The free energy value (ΔGads indicated that the adsorption of inhibitor molecules was typical of physisorption. The results obtained show that N. tabacum Extract could serve as an excellent eco-friendly green corrosion inhibitor. Quantum chemical parameters such as highest occupied molecular orbital energy (EHOMO, lowest unoccupied molecular orbital energy (ELUMO, energy gap (ΔE, dipole moment (μ and Mulliken charges were calculated. Quantum chemical calculations also supported experimental data and the adsorption of inhibitor molecules onto the metal surface.

  12. Biofilm-Growing Bacteria Involved in the Corrosion of Concrete Wastewater Pipes: Protocols for Comparative Metagenomic Analyses

    Science.gov (United States)

    Advances in high-throughput next-generation sequencing (NGS) technology for direct sequencing of environmental DNA (i.e. shotgun metagenomics) is transforming the field of microbiology. NGS technologies are now regularly being applied in comparative metagenomic studies, which pr...

  13. Study on an On-line Measurement System of Corrosion Rate by Linear Polarization Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Jeon Soo; Lee, Jae Kun; Lee, Jae Bong; Park, Pyl Yang [Korea Electric Power Research Institute, Daejeon (Korea, Republic of)

    2012-04-15

    The linear polarization resistance method is one of the widely used techniques for the corrosion rate monitoring in the water circulating systems of plants. The measurement is simple and rapid, so that a continuous on-line monitoring is possible without any shutdown of plants. A 2-electrode polarization corrosion rate measurement system was installed in a laboratory using a data acquisition board and PC. The signal processing parameters were optimized for the accurate corrosion rate measurement, and the polarization resistance was compensated with the solution resistance measured by the high frequency sine wave signal of an output channel. The precision of corrosion rate data was greatly improved by removing the initial noise signals on measuring the polarization resistance.

  14. Study of the corrosion products formed on carbon steels in the tropical atmosphere of Panama

    Energy Technology Data Exchange (ETDEWEB)

    Jaen, J. A.; Villalaz, M. S. de; Araque, L. de; Hernandez, C.; Bosquez, A. de

    2003-07-01

    Moessbauer spectroscopy and X-ray powder diffraction (in selected samples) have been used to characterize corrosion products on carbon steels after atmospheric exposure to the tropical Panamanian locations of Panama and Colon, classified according to ISO 9233 as C3 and C5, respectively. Goethite ({alpha}-FeOOH) of intermediate particle size (20-100 nm), lepidocrocite ({gamma}-FeOOH), a spinel phase consisting of non-stoichiometric magnetite (Fe{sub 3}-xO{sub 4}) and/or maghemita ({gamma}-Fe{sub 2}O{sub 3}) and nano-sized particles were identified in the corrosion products. The spinel phase is related to short term atmospheric exposure transforms in time to other corrosion products. The corrosion resistance increased with fraction of goethite following a saturation-type behavior. (Author) 13 refs.

  15. Inhibitive Performance of Benzotriazole for Steel Corrosion Studied by Electrochemical and AFM Characterization

    Science.gov (United States)

    Feng, Yuanchao; Cheng, Y. Frank

    2015-12-01

    In this work, the inhibiting effect of benzotriazole (BTA) on corrosion of X65 pipeline steel in bicarbonate solution was investigated by electrochemical measurements, including open-circuit potential, potentiodynamic polarization curves and electrochemical impedance spectroscopy, and atomic force microscopy characterization. It is found that BTA is effective to inhibit the steel corrosion, and the inhibiting efficiency is increased by the increasing inhibitor concentration. The BTA is an anodic inhibitor, which shifts the corrosion potential of the steel less negatively and decreases the anodic current density at individual potential. A layer of inhibitor film is formed on the steel surface to reduce the corrosion rate of the steel. The formed film is quite smooth, with a roughness at the nano-meter scale.

  16. Speciation study of chromium corrosion product in molten LiF-NaF-KF salt

    Institute of Scientific and Technical Information of China (English)

    邱杰; 邹杨; 俞国军; 何上明; 刘文冠; 贾彦彦; 李志军; 徐洪杰

    2015-01-01

    To investigate the corrosion products of Cr in molten FLiNaK salt (46.5 mol% LiF–11.5 mol% NaF–42 mol%KF), the corrosion test of the pure metal Cr was performed in molten FLiNaK salt at 700◦C for 200 h. The FLiNaK salt after the corrosion test was thoroughly investigated by X-ray absorption near-edge structure spectroscopy, a transmission electron microscope, and X-ray diffraction. The results demonstrate that the pre-dominant oxidation state of Cr in FLiNaK salt is Cr3+, and the main corrosion product in cooled FLiNaK salt is K2NaCrF6.

  17. Progressive Corrosion Study of Metals like Mild Steel, Zinc and Aluminium in an Urban Atmosphere

    Directory of Open Access Journals (Sweden)

    H. K. Kadiya

    2009-01-01

    Full Text Available Corrosion rate (Progressive of mild steel (MS, zinc and aluminum have been determined under outdoor conditions of exposure at Valsad (South Gujarat representing an urban atmosphere. Mild steel (MS, zinc and aluminium plates exposed during November 2005 indicates corrosion rate of 88, 33 and 1.4 mg/sq.dm for one month exposure period and 3668, 968 and 26.1 mg/sq.dm for mild steel, zinc and aluminium respectively for twelve months exposure period. Mild steel panels exposed vertically suffer less corrosion than those exposed at an angle of 45°. The resistivity towards the atmosphere was in the increasing order: mild steel < zinc < aluminium. Corrosion rate of these three metals found more in rainy seasons than the rate of winter and summer season

  18. Corrosion Evaluation and Corrosion Control of Steam Generators

    Energy Technology Data Exchange (ETDEWEB)

    Maeng, W. Y.; Kim, U. C.; Sung, K. W.; Na, J. W.; Lee, Y. H.; Lee, D. H.; Kim, K. M

    2008-06-15

    Corrosion damage significantly influences the integrity and efficiency of steam generator. Corrosion problems of steam generator are unsolved issues until now even though much effort is made around world. Especially the stress corrosion cracking of heat exchange materials is the first issue to be solved. The corrosion protection method of steam generator is important and urgent for the guarantee of nuclear plant's integrity. The objectives of this study are 1) to evaluate the corrosion properties of steam generator materials, 2) to optimize the water chemistry of steam generator and 3) to develop the corrosion protection method of primary and secondary sides of steam generator. The results will be reflected to the water chemistry guideline for improving the integrity and efficiency of steam generator in domestic power plants.

  19. The Growth of Small Corrosion Fatigue Cracks in Alloy 7075

    Science.gov (United States)

    Piascik, Robert S.

    2015-01-01

    The corrosion fatigue crack growth characteristics of small (greater than 35 micrometers) surface and corner cracks in aluminum alloy 7075 is established. The early stage of crack growth is studied by performing in situ long focal length microscope (500×) crack length measurements in laboratory air and 1% sodium chloride (NaCl) environments. To quantify the "small crack effect" in the corrosive environment, the corrosion fatigue crack propagation behavior of small cracks is compared to long through-the-thickness cracks grown under identical experimental conditions. In salt water, long crack constant K(sub max) growth rates are similar to small crack da/dN.

  20. A Study of Transport Processes and Initiation of Corrosion Under Paint Films.

    Science.gov (United States)

    1979-11-01

    1979 meeting of The Electrochemical Society (9). Once the feasibility of oxygen diffusion through a porous tail had been firmly established... Electrochemical Society , Los Angeles, CA, October 18, 1979. 10. G. M. Hoch, Int. Corrosion Conf. Ser., 1971, Published 1974, NACE 3, Localized Corrosion, 134-142...34Conservation of Energy in the Electrochemical Process Industries," by T. R. Beck, N. P. Yao, and A. R. Landgrebe. The Electrochemical Society , Las Vegas Meeting

  1. STUDY ON CORROSION RESISTANCE OF REBAR IN HYBRID GRINDING FLY ASH-LIME SILICATE CONCRETE

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The corrosion resistance of rebar in fly ash-lime sili cate concrete as well as its marco properties and pore distribution is investiga ted.The results show that the fly ash is activated, the compressive strength of the silicate concrete is strengthened and its pore structure is modified after f ly ash and lime being hybrid ground.Also the corrosion resistance of rebar in the silicate concrete is improved.

  2. Review and Study of Physics Driven Pitting Corrosion Modeling in 2024-T3 Aluminum Alloys (Postprint)

    Science.gov (United States)

    2015-05-01

    measuring the maximum pit size and its effect on the fatigue life. Microstructure and corrosion currents were neglected. In this paper we present the...Figure 2 Appearance of the pits on the surface of 7075 -T6 (Wang et al., 2003) Proc. of SPIE Vol. 9437 94372E-2 2 Distribution Statement A. Approved... density (Harlow and Wei, 1994). It can be seen that the definition of pitting current Ip is the key element in the pitting corrosion modeling, which

  3. Synergy effect of naphthenic acid corrosion and sulfur corrosion in crude oil distillation unit

    Science.gov (United States)

    Huang, B. S.; Yin, W. F.; Sang, D. H.; Jiang, Z. Y.

    2012-10-01

    The synergy effect of naphthenic acid corrosion and sulfur corrosion at high temperature in crude oil distillation unit was studied using Q235 carbon-manganese steel and 316 stainless steel. The corrosion of Q235 and 316 in corrosion media containing sulfur and/or naphthenic acid at 280 °C was investigated by weight loss, scanning electron microscope (SEM), EDS and X-ray diffractometer (XRD) analysis. The results showed that in corrosion media containing only sulfur, the corrosion rate of Q235 and 316 first increased and then decreased with the increase of sulfur content. In corrosion media containing naphthenic acid and sulfur, with the variations of acid value or sulfur content, the synergy effect of naphthenic acid corrosion and sulfur corrosion has a great influence on the corrosion rate of Q235 and 316. It was indicated that the sulfur accelerated naphthenic acid corrosion below a certain sulfur content but prevented naphthenic acid corrosion above that. The corrosion products on two steels after exposure to corrosion media were investigated. The stable Cr5S8 phases detected in the corrosion products film of 316 were considered as the reason why 316 has greater corrosion resistance to that of Q235.

  4. Ultimate strength performance of tankers associated with industry corrosion addition practices

    Science.gov (United States)

    Kim, Do Kyun; Kim, Han Byul; Zhang, Xiaoming; Li, Chen Guang; Paik, Jeom Kee

    2014-09-01

    In the ship and offshore structure design, age-related problems such as corrosion damage, local denting, and fatigue damage are important factors to be considered in building a reliable structure as they have a significant influence on the residual structural capacity. In shipping, corrosion addition methods are widely adopted in structural design to prevent structural capacity degradation. The present study focuses on the historical trend of corrosion addition rules for ship structural design and investigates their effects on the ultimate strength performance such as hull girder and stiffened panel of double hull oil tankers. Three types of rules based on corrosion addition models, namely historic corrosion rules (pre-CSR), Common Structural Rules (CSR), and harmonised Common Structural Rules (CSRH) are considered and compared with two other corrosion models namely UGS model, suggested by the Union of Greek Shipowners (UGS), and Time-Dependent Corrosion Wastage Model (TDCWM). To identify the general trend in the effects of corrosion damage on the ultimate longitudinal strength performance, the corrosion addition rules are applied to four representative sizes of double hull oil tankers namely Panamax, Aframax, Suezmax, and VLCC. The results are helpful in understanding the trend of corrosion additions for tanker structures

  5. Corrosion-Inhibitor Efficiency Control: Comparison by Means of Different Portable Corrosion Rate Meters

    OpenAIRE

    Martinez Sierra, Isabel; Andrade Perdrix, Maria del Carmen; Rebolledo Ramos, Nuria; Luo, L; De Schutter, G

    2010-01-01

    Corrosion-inhibiting substances have been applied to suppress corrosion mainly on bare steel, but when corrosion is progressing, suppression can be achieved if anodic and cathodic reactions are avoided, which is not an easy objective, particularly if the bare metal is surrounded by concrete. In the present article, several corrosion inhibitors are studied to identify their inhibition efficiency in concrete. The percentage of reduction of the corrosion rate without and with inhibitor is named ...

  6. Automated Methods of Corrosion Measurements

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    1997-01-01

    electrochemical measurements as well as elemental analysis look very promising for elucidating corrosion reaction mechanisms. The study of initial surface reactions at the atomic or submicron level is becoming an important field of research in the understanding of corrosion processes. At present, mainly two...... scanning microscope techniques are employed investigating corrosion processes, and usually in situ: in situ scanning tunneling microscopy (in situ STM) and in situ scanning force microscopy (in situ AFM). It is these techniques to which attention is directed here....

  7. Benchmarked Library Websites Comparative Study

    KAUST Repository

    Ramli, Rindra M.

    2015-01-01

    This presentation provides an analysis of services provided by the benchmarked library websites. The exploratory study includes comparison of these websites against a list of criterion and presents a list of services that are most commonly deployed by the selected websites. In addition to that, the investigators proposed a list of services that could be provided via the KAUST library website.

  8. Corrosion-resistant metallic coatings

    Directory of Open Access Journals (Sweden)

    F. Presuel-Moreno

    2008-10-01

    Full Text Available We describe recent computational and experimental studies on the corrosion properties of metallic coatings that can be tailored (tuned to deliver up to three corrosion-inhibiting functions to an underlying substrate. Attributes are tuned by a selection of alloy compositions and nanostructures, ideally in alloy systems that offer flexibility of choice to optimize the corrosion-resisting properties. An amorphous Al-based coating is tuned for corrosion protection by on-demand release of ionic inhibitors to protect defects in the coating, by formation of an optimized barrier to local corrosion in Cl− containing environments, as well as by sacrificial cathodic prevention. Further progress in this field could lead to the design of the next generation of adaptive or tunable coatings that inhibit corrosion of underlying substrates.

  9. Corrosion fatigue studies on F82H mod. martensitic steel in reducing water coolant environments

    Energy Technology Data Exchange (ETDEWEB)

    Maday, M.F.; Masci, A. [ENEA, Casaccia (Italy). Centro Ricerche Energia

    1998-03-01

    Load-controlled low cycle fatigue tests have been carried out on F82H martensitic steel in 240degC oxygen-free water with and without dissolved hydrogen, in order to simulate realistic coolant boundary conditions to be approached in DEMO. It was found that water independently of its hydrogen content, determined the same fatigue life reduction compared to the base-line air results. Water cracks exhibited in their first propagation stages similar fracture morphologies which were completely missing on the air cracks, and were attributed to the action of an environment related component. Lowering frequency gave rise to an increase in F82H fatigue lifetimes without any change in cracking mode in air, and to fatigue life reduction by microvoid coalescence alone in water. The data were discussed in terms of (i) frequency dependent concurrent processes for crack initiation and (ii) frequency-dependent competitive mechanisms for crack propagation induced by cathodic hydrogen from F82H corrosion. (author)

  10. The Application of Electrochemical and Surface Analysis Approaches to Studying Copper Corrosion in Water: Fundamentals, Limitations, and Examples

    Science.gov (United States)

    Corrosion control is a concern for many drinking water utilities. The Lead and Copper Rule established a regulatory need to maintain a corrosion control program. Other corrosion-related issues such as “red” water resulting from excessive iron corrosion and copper pinhole leaks ...

  11. Positive aspects issued from bio corrosion studies: from hydrogen production to biofuel cells; Des aspects positifs issus des recherches en biocorrosion: de la production d'hydrogene aux biopiles a combustible

    Energy Technology Data Exchange (ETDEWEB)

    Silva Munoz, L. de

    2007-12-15

    Microbially influenced corrosion or bio corrosion is a problem that generates heavy global economic losses (several billion euros per year). In spite of the progress made on the understanding of the underlying mechanisms, the complexity of the phenomenon has prevented finding definitive solutions to the problem and continues to inspire many research works. The participation in bio corrosion of catalytic mechanisms induced by weak acids was studied in this work. Another objective of the thesis has been to take advantage from catalytic phenomena found in bio corrosion research to apply them in other areas: energy production with biofuel cells or electrochemical hydrogen production in mild conditions. This work has shown that the presence of weak acids and amino acids inside bio-films could play a major role in steel bio corrosion accelerating the phenomenon through the catalysis of the water reduction reaction. The reversibility of this mechanism, discerned and proved here, could explain the corrosion increase when hydrogen is removed (bacterial consumption, agitation...). In addition, phosphates allow the production of hydrogen by electrolysis in mild pH conditions (pH 4.0 - 8.0) with an equal or better performance than those found in alkaline electrolysis. Finally, industrial materials like stainless steel and titanium could be used in the fabrication of enzymatic electrodes for biosensors or microsystems. The use of the glucose oxidase/glucose system in an aqueous fuel cell with a stainless steel cathode, allows the improvement of the cell performance thanks to the production of hydrogen peroxide that is easily reduced. Moreover, the use of materials with micro-structured surfaces like sandblasted steels deserve to be studied in detail to exploit the remarkable reactivity they present compared to smooth electrodes. (author)

  12. Corrosion study on high power feeding of telecomunication copper cable in 5 wt.% CaSO4.2H2O solution

    Science.gov (United States)

    Shamsudin, Shaiful Rizam; Hashim, Nabihah; Ibrahim, Mohd Saiful Bahri; Rahman, Muhammad Sayuzi Abdul; Idrus, Muhammad Amin; Hassan, Mohd Rezadzudin; Abdullah, Wan Razli Wan

    2016-07-01

    The studies were carried out to find out the best powering scheme over the copper telephone line. It was expected that the application of the higher power feeding could increase the data transfer and capable of providing the customer's satisfaction. To realize the application of higher remote power feeding, the potential of corrosion problem on Cu cables was studied. The natural corrosion behaviour of copper cable in the 0.5% CaSO4.2H2O solution was studied in term of open circuit potential for 30 days. The corrosion behaviour of higher power feeding was studied by the immersion and the planned interval test to determine the corrosion rate as well as the effect of voltage magnitudes and the current scheme i.e. positive direct (DC+) and alternating current (AC) at about 0.40 ± 0.01 mA/ cm2 current density. In the immersion test, both DC+ and AC scheme showed the increasing of feeding voltage magnitude has increased the corrosion rate of Cu samples starting from 60 to 100 volts. It was then reduced at about 100 - 120 volts which may due to the passive and transpassive mechanism. The corrosion rate was slowly reduced further from 120 to 200 volts. Visually, the positively charged of Cu cable was seems susceptible to severe corrosion, while AC scheme exhibited a slight corrosion reaction on the surface. However, the planned interval test and XRD results showed the corrosion activity of the copper cable in the studied solution was a relatively slow process and considered not to be corroded as a partially protective scale of copper oxide formed on the surface.

  13. New Developments in Mitigation of Microbiologically Influenced Corrosion

    Science.gov (United States)

    2007-07-12

    experiment to evaluate deoxygenation of natural seawater as a corrosion control measure for unprotected carbon steel seawater ballast tanks. They...either consistently aerobic or deoxygenated conditions. CONCLUSIONS: It is difficult to compare the laboratory studies on corrosion inhibition due to...using nitrogen gas. Report of Research and Development to the Ship and Ocean Foundation. 1999 October, Japan. 31. Lee JS, Ray RI, Lemieux E, Falster A

  14. Study of corrosion in archaeological gilded irons by Raman imaging and a coupled scanning electron microscope-Raman system

    Science.gov (United States)

    Veneranda, Marco; Costantini, Ilaria; de Vallejuelo, Silvia Fdez-Ortiz; Garcia, Laura; García, Iñaki; Castro, Kepa; Azkarate, Agustín; Madariaga, Juan Manuel

    2016-12-01

    In this work, analytical and chemical imaging tools have been applied to the study of a gilded spur found in the medieval necropolis of Erenozar (Bizkaia, Spain). As a first step, a lot of portable equipment has been used to study the object in a non-invasive way. The hand-held energy-dispersive X-ray fluorescence equipment allowed us to characterize the artefact as a rare example of an iron matrix item decorated by means of a fire gilding technique. On the other hand, the use of a portable Raman system helped us to detect the main degradation compounds affecting the spur. Afterwards, further information was acquired in the laboratory by analysing detached fragments. The molecular images obtained using confocal Raman microscopy permitted us to characterize the stratigraphic succession of iron corrosions. Furthermore, the combined use of this technique with a scanning electron microscope (SEM) was achieved owing to the use of a structural and chemical analyser interface. In this way, the molecular characterization, enhanced by the magnification feature of the SEM, allowed us to identify several micrometric degradation compounds. Finally, the effectiveness of one of the most used desalination baths (NaOH) was evaluated by comparing its effects with those provided by a reference bath (MilliQ). The comparison proved that basic treatment avoided any side effects on the spur decorated by fire gilding, compensating for the lack of bibliographic documentation in this field. This article is part of the themed issue "Raman spectroscopy in art and archaeology".

  15. Contribution to the Study of Effects of Surface State of Welded Joints in Stainless Steel Upon Resistance Towards Pitting Corrosion

    Directory of Open Access Journals (Sweden)

    Juraga, I.

    2007-01-01

    Full Text Available Successful corrosion resistance of stainless steels is based on their natural ability of passivation, i.e. formation of film of chromium oxides that prevents corrosion in many environments. Any nonuniformity of surface layers may be initial spot for corrosion processes and damages. In this contribution, beside real corrosion damages occurred in practice, results of testing of pitting corrosion resistance of weld beads made applying TIG process on AISI 316L steel grade are presented. SEM and EDX testing, as well as electrochemical corrosion testing confirmed adverse effects of heat tints zones upon corrosion resistance of stainless steels.

  16. The Comparative Effect of Sugarcane Juice on the Abrasion-Corrosion Behavior of Fe-Cr-B Electric Arc Sprayed and Fe-Cr-C Weld Coatings

    Science.gov (United States)

    Buchanan, Vernon E.

    2012-02-01

    Abrasion-corrosion tests were conducted on two commonly Fe-Cr-C shielded metal arc welding (SMAW) hardfacings used in the sugar industry and an arc sprayed Fe-Cr-based coating. The tests were performed on a modified block-on-ring tester with the coatings sliding against compressed sugarcane fiber in the presence of abrasive slurry. The findings showed that, in the presence of sugarcane juice and sand slurry, the SMAW coatings had similar wear performance while the abrasive wear of the arc-sprayed coating was superior to the SMAW coatings. In the presence of a neutral solution, the material loss from the arc-sprayed coating was similar to that obtained in the sugarcane juice while the SMAW coatings showed a marked decrease; this demonstrated that the arc-sprayed coating was more desirable in an abrasive-corrosion environment. The study also showed that the resistance to material does not follow the expected trend, in which wear resistance increases with increasing hardness.

  17. Mechanisms of metal dusting corrosion

    DEFF Research Database (Denmark)

    Hummelshøj, Thomas Strabo

    In this thesis the early stages of metal dusting corrosion is addressed; the development of carbon expanded austenite, C, and the decomposition hereof into carbides. Later stages of metal dusting corrosion are explored by a systematic study of stainless steel foils exposed to metal dusting...... influence of oxygen and carbon on the metal dusting corrosion is explored. The results indicate that exposure to metal dusting conditions have a detrimental effect on the resistance against oxidation and, conversely, that exposure to oxidation has a detrimental effect on the resistance towards metal dusting....... Consequently, a combination of carburizing and oxidizing conditions has a strong mutual catalyzing effect on the metal dusting corrosion....

  18. Adsorption and Corrosion Inhibition Studies of Some Selected Dyes as Corrosion Inhibitors for Mild Steel in Acidic Medium: Gravimetric, Electrochemical, Quantum Chemical Studies and Synergistic Effect with Iodide Ions

    Directory of Open Access Journals (Sweden)

    Thabo Peme

    2015-09-01

    Full Text Available The corrosion inhibition properties of some organic dyes, namely Sunset Yellow (SS, Amaranth (AM, Allura Red (AR, Tartrazine (TZ and Fast Green (FG, for mild steel corrosion in 0.5 M HCl solution, were investigated using gravimetric, potentiodynamic polarization techniques and quantum chemical calculations. The results showed that the studied dyes are good corrosion inhibitors with enhanced inhibition efficiencies. The inhibition efficiency of all the studied dyes increases with increase in concentration, and decreases with increase in temperature. The results showed that the inhibition efficiency of the dyes increases in the presence of KI due to synergistic interactions of the dye molecules with iodide (I− ions. Potentiodynamic polarization results revealed that the studied dyes are mixed-type inhibitors both in the absence and presence of KI. The adsorption of the studied dyes on mild steel surface, with and without KI, obeys the Langmuir adsorption isotherm and involves physical adsorption mechanism. Quantum chemical calculations revealed that the most likely sites in the dye molecules for interactions with mild steel are the S, O, and N heteroatoms.

  19. Adsorption and Corrosion Inhibition Studies of Some Selected Dyes as Corrosion Inhibitors for Mild Steel in Acidic Medium: Gravimetric, Electrochemical, Quantum Chemical Studies and Synergistic Effect with Iodide Ions.

    Science.gov (United States)

    Peme, Thabo; Olasunkanmi, Lukman O; Bahadur, Indra; Adekunle, Abolanle S; Kabanda, Mwadham M; Ebenso, Eno E

    2015-09-02

    The corrosion inhibition properties of some organic dyes, namely Sunset Yellow (SS), Amaranth (AM), Allura Red (AR), Tartrazine (TZ) and Fast Green (FG), for mild steel corrosion in 0.5 M HCl solution, were investigated using gravimetric, potentiodynamic polarization techniques and quantum chemical calculations. The results showed that the studied dyes are good corrosion inhibitors with enhanced inhibition efficiencies. The inhibition efficiency of all the studied dyes increases with increase in concentration, and decreases with increase in temperature. The results showed that the inhibition efficiency of the dyes increases in the presence of KI due to synergistic interactions of the dye molecules with iodide (I(-)) ions. Potentiodynamic polarization results revealed that the studied dyes are mixed-type inhibitors both in the absence and presence of KI. The adsorption of the studied dyes on mild steel surface, with and without KI, obeys the Langmuir adsorption isotherm and involves physical adsorption mechanism. Quantum chemical calculations revealed that the most likely sites in the dye molecules for interactions with mild steel are the S, O, and N heteroatoms.

  20. Study of alloy 600`S stress corrosion cracking mechanisms in high temperature water; Etude des mecanismes de corrosion sous contrainte de l`alliage 600 dans l`eau a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Rios, R.

    1994-06-01

    In order to better understand the mechanisms involved in Alloy 600`s stress corrosion cracking in PWR environment, laboratory tests were performed. The influence of parameters pertinent to the mechanisms was studies : hydrogen and oxygen overpressures, local chemical composition, microstructure. The results show that neither hydrogen nor dissolution/oxidation, despite their respective roles in the process, are sufficient to account for experimental facts. SEM observation of micro-cleavage facets on specimens` fracture surfaces leads to pay attention to a new mechanism of corrosion/plasticity interactions. (author). 113 refs., 73 figs., 15 tabs., 4 annexes.

  1. Corrosion in airframes

    OpenAIRE

    PETROVIC ZORAN C.

    2016-01-01

    The introductory chapter provides a brief reference to the issue of corrosion and corrosion damage to aircraft structures. Depending on the nature and dimensions of this non uniformity, three different categories of corrosion are defined: uniform, selective and localized corrosion. The following chapters present the forms of corrosion that can occur in three defined categories of corrosion. Conditions that cause certain types of corrosion in various corrosive environments are discussed. Examp...

  2. CORROSION IN AIRFRAMES

    OpenAIRE

    PETROVIC ZORAN C.

    2016-01-01

    The introductory chapter provides a brief reference to the issue of corrosion and corrosion damage to aircraft structures. Depending on the nature and dimensions of this non uniformity, three different categories of corrosion are defined: uniform, selective and localized corrosion. The following chapters present the forms of corrosion that can occur in three defined categories of corrosion. Conditions that cause certain types of corrosion in various corrosive environments are discussed. Examp...

  3. The corrosion protection of several aluminum alloys by chromic acid and sulfuric acid anodizing

    Science.gov (United States)

    Danford, M. D.

    1994-01-01

    The corrosion protection afforded 7075-T6, 7075-T3, 6061-T6, and 2024-T3 aluminum alloys by chromic acid and sulfuric acid anodizing was examined using electrochemical techniques. From these studies, it is concluded that sulfuric acid anodizing provides superior corrosion protection compared to chromic acid anodizing.

  4. Study of ferrous corrosion products on iron archaeological objects by electron backscattered diffraction (EBSD)

    Energy Technology Data Exchange (ETDEWEB)

    Azoulay, Ilanith; Conforto, Egle; Refait, Philippe; Remazeilles, Celine [FRE 3474 CNRS - Universite de La Rochelle, Laboratoire des Sciences de l' Ingenieur pour l' Environnement, La Rochelle cedex 01 (France)

    2013-02-15

    The corrosion of iron-based archaeomaterials in anoxic environments leads mainly to Fe(II) compounds, like the hydroxychloride {beta}-Fe{sub 2}(OH){sub 3}Cl, chukanovite Fe{sub 2}(OH){sub 2}CO{sub 3} or siderite FeCO{sub 3}. The understanding of the mechanisms then necessarily implies a thorough investigation of the chemical, mechanical and morphological characteristics of the Fe(II)-based layer that develops between the metal surface and the environment. In the peculiar case of Fe(II) compounds, generally very reactive towards O{sub 2}, the main concern is to prevent any transformation by air during the analysis. The EBSD technique is adapted on a scanning electron microscope (SEM) where the samples are analysed under vacuum and consequently sheltered from air. Different options offered by EBSD for phase characterisation and microstructural study were tested for the first time on the rust layers of two archaeological iron nails. Results were confronted to those obtained by micro-Raman spectroscopy, which was used as reference method. Magnetite, Fe(II) hydroxychloride {beta}-Fe{sub 2}(OH){sub 3}Cl and siderite were analysed successfully but improvements have to be brought for the study of other compounds such as iron oxyhydroxides and chukanovite. The choice of experimental parameters in our approach as well as the potentialities and limits of the technique for this kind of application are discussed. (orig.)

  5. Study of ferrous corrosion products on iron archaeological objects by electron backscattered diffraction (EBSD)

    Science.gov (United States)

    Azoulay, Ilanith; Conforto, Egle; Refait, Philippe; Rémazeilles, Céline

    2013-02-01

    The corrosion of iron-based archaeomaterials in anoxic environments leads mainly to Fe(II) compounds, like the hydroxychloride β-Fe2(OH)3Cl, chukanovite Fe2(OH)2CO3 or siderite FeCO3. The understanding of the mechanisms then necessarily implies a thorough investigation of the chemical, mechanical and morphological characteristics of the Fe(II)-based layer that develops between the metal surface and the environment. In the peculiar case of Fe(II) compounds, generally very reactive towards O2, the main concern is to prevent any transformation by air during the analysis. The EBSD technique is adapted on a scanning electron microscope (SEM) where the samples are analysed under vacuum and consequently sheltered from air. Different options offered by EBSD for phase characterisation and microstructural study were tested for the first time on the rust layers of two archaeological iron nails. Results were confronted to those obtained by micro-Raman spectroscopy, which was used as reference method. Magnetite, Fe(II) hydroxychloride β-Fe2(OH)3Cl and siderite were analysed successfully but improvements have to be brought for the study of other compounds such as iron oxyhydroxides and chukanovite. The choice of experimental parameters in our approach as well as the potentialities and limits of the technique for this kind of application are discussed.

  6. Cement corrosion in oil and gas wells. Literature study; Zementkorrosion bei Oel- und Gasbohrungen. Literaturstudie

    Energy Technology Data Exchange (ETDEWEB)

    Plank, J.; Brandl, A. [Technische Univ. Muenchen (Germany). Lehrstuhl fuer Bauchemie

    2009-07-15

    The goal of DGMK-project 652 is to determine the main factors which are responsible for cement corrosion in oil and gas wells, and to develop concepts for improvements with respect to the cement slurry formulation, the cementing process and the impact of factors such as temperature, electrolyte containing reservoir fluids, cement admixtures, sour gas, CO{sub 2} acids etc. To determine the state of the art, a literature survey in relevant journals and monographies with the help of data banks was performed. The results are presented in this report. At first, a detailed description of the chemistry and mineralogy of oil well cement and its corrosion processes is given. Then, current experiences from conventional concrete technology as well as the oilfield are presented. The state of art of cement corrosion in the oilfield was investigated. Overall, little literature about cement corrosion in oil and gas wells exists. In particular, only a few field reports were ever published. The subject of cement corrosion is mainly presented in the form of laboratory tests simulating certain conditions and using common analytical methods. (orig.)

  7. Study of metal corrosion using ac impedance techniques in the STS launch environment

    Science.gov (United States)

    Calle, Luz M.

    1989-01-01

    AC impedance measurements were performed to investigate the corrosion resistance of 19 alloys under conditions similar to the STS launch environment. The alloys were: Zirconium 702, Hastelloy C-22, Inconel 625, Hastelloy C-276, Hastelloy C-4, Inconel 600, 7Mo + N, Ferralium 255, Inco Alloy G-3, 20Cb-3, SS 904L, Inconel 825, SS 304LN, SS 316L, SS 317L, ES 2205, SS 304L, Hastelloy B-2, and Monel 400. AC impedance data were gathered for each alloy after one hour immersion time in each of the following three electrolyte solutions: 3.55 percent NaCl, 3.55 percent NaCl-0.1N HCl, and 3.55 percent NaCl-1.0N HCl. The data were analyzed qualitatively using the Nyquist plot and quantitatively using the Bode plot. Polarization resistance, Rp, values were obtained using the Bode plot. Zirconium 702 was the most corrosion resistant alloy in the three electrolytes. The ordering of the other alloys according the their resistance to corrosion varied as the concentration of hydrochloric acid in the electrolyte increased. The corrosion resistance of Zirconium 702 and Ferralium 255 increased as the concentration of hydrochloric acid in the electrolyte increased. The corrosion resistance of the other 17 alloys decreased as the concentration of the hyrdochloric acid in the electrolyte increased.

  8. Study on Polymer(JR)Cement Resisting Corrosion of Corrosive Performance by Carbon Dioxide%聚合物(JR)水泥抗二氧化碳腐蚀性能研究

    Institute of Scientific and Technical Information of China (English)

    王杰; 兰新生; 张力; 苏璟; 叶春燕

    2015-01-01

    This paper studies that the microstructure, changes of the composition and corrosion ratio, strength and permeability of cement stone before and after corrosion were analyzed with the method of X-ray diffraction(XRD),scanning electron microscope (SEM) and chemistry, The discussion that concentration of CO2 and temperature have effect on the cement corrosion characteristics and polymer JR resistances CO2 corrosion of mechanism. The results show the microstructure scanning seen a layer of impermeable membrane on cement surface by adding polymer JR, The corrosion products is the reaction of CO2 and a small amount of cement in the Ca(OH)2 and C-S-H by XRD;The internal structure and cementations materials of corrosion cement stone is not damaged. The polymer JR can effectively reduces the permeability of cement stone;Increasing the concentration of CO2 will intensify the corrosion rate, the loss of strength of cement stone and the increasing of permeability;The corrosion cement has a significantly larger turning point as the concentration of CO2 between 0.15 and 0.2. The polymer of cement has good effects of anti CO2 corrosion when the concentration of CO2 is less than 0.15;Under a certain concentration of CO2, the relationship between corrosion temperature and corrosion ratio is quadratics;Being covered non permeable polymer membranes on surface of cement stone and being filled polymer particles in cement stone pore have increased polymer JR of cement stone resistance corrosion of CO2.%本文利用化学、XRD和SEM等手段分析聚合物JR水泥腐蚀后的腐蚀率、强度、渗透率及水泥石微观结构和组成变化,探讨CO2浓度、腐蚀温度对聚合物JR水泥腐蚀性能影响和抗CO2腐蚀机理。结果表明:掺加聚合物JR后,SEM观察在水泥石表面上形成一层非渗透性膜,腐蚀后产物经XRD分析,水泥石中只有少量的Ca(OH)2和C-S-H碱性物质与CO2发生反应;腐蚀后水泥石内部结构和胶

  9. Study on Corrosion Inhibition Efficiency of Stem Alkaloid Extract of Different Varieties of Holy Basil on Aluminium in HCl Solution

    Energy Technology Data Exchange (ETDEWEB)

    Kumpawat, Nutan; Chaturvedi, Alok; Upadhyay, R. K. [Synthetic and Surface Science Laboratory, Ajmer (India)

    2012-08-15

    Corrosion inhibition efficiencies of holy basil on Al in HCl solution were studied by weight loss and thermometric methods in presence and in absence of stem extract of three different varieties of holy basil viz. ocimum basilicum (E{sub B}), ocimum canum (E{sub C}) and ocimum sanctum (E{sub S}). Inhibition efficiency increases with the increasing concentration of stem extract and decreases with increases in acid strength. Results show that all varieties under study are good corrosion inhibitors, among which, E{sub B} is most effective. Maximum inhibition efficiency was found 97.09% in 0.5N HCl solution with 0.6% stem extract. The Langmuir adsorption isotherm indicates that surface coverage also increases with increasing in the concentration of extract of stem in HCl solution.

  10. A Study of Magnesium-Base Metallic Systems and Development of Principles for Creation of Corrosion-Resistant Magnesium Alloys

    Science.gov (United States)

    Mukhina, I. Yu.

    2014-11-01

    The effect of 26 alloying elements on the corrosion resistance of high-purity magnesium in a 0.5-n solution of sodium chloride and in a humid atmosphere (0.005 n) is studied. The Mg - Li, Mg - Ag, Mg - Zn, Mg - Cu, Mg - Gd, Mg - Al, Mg - Zr, Mg - Mn and other binary systems, which present interest as a base for commercial or perspective castable magnesium alloys, are studied. The characteristics of corrosion resistance of the binary alloys are analyzed in accordance with the group and period of the Mendeleev's periodic law. The roles of the electrochemical and volume factors and of the factor of the valence of the dissolved element are determined.

  11. Feasibility Study on Nano-structured Coatings to Mitigate Flow-accelerated Corrosion in Secondary System of Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seunghyun; Kim, Jeong Won; Kim, Ji Hyun [Ulsan National Institute of Science and Technology, Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan (Korea, Republic of)

    2015-05-15

    There have been many efforts to mitigate FAC through the adoption of the advanced and modified water chemistries such as optimized dissolved oxygen (DO) concentration and temperature. However, these mitigation techniques pose certain challenges relating to the compatibility of new water chemistries with the steam generator, the thermal efficiency of the secondary side, etc. In this context, nano-particle reinforced electroless nickel plating (NP ENP) could help solve the FAC issues in secondary pipe systems. This does not require modification of water chemistry or structural materials, and hence, its application is reasonable and time-saving compared to previous FAC mitigation techniques. The main parameters of FAC are known as electrochemical reaction at the interface, dissolution of magnetite and ferrous ions due to concentration gradient between carbon steels and water and wear due to a fast-flowing fluid. High-temperature corrosion characteristics of the both coatings have potential as FAC barrier for carbon steel. Feasibility study will be carried out with FAC simulation experiments.

  12. Corrosion in drinking water pipes: the importance of green rusts.

    Science.gov (United States)

    Swietlik, Joanna; Raczyk-Stanisławiak, Urszula; Piszora, Paweł; Nawrocki, Jacek

    2012-01-01

    Complex crystallographic composition of the corrosion products is studied by diffraction methods and results obtained after different pre-treatment of samples are compared. The green rusts are found to be much more abundant in corrosion scales than it has been assumed so far. The characteristic and crystallographic composition of corrosion scales and deposits suspended in steady waters were analyzed by X-ray diffraction (XRD). The necessity of the examination of corrosion products in the wet conditions is indicated. The drying of the samples before analysis is shown to substantially change the crystallographic phases originally present in corrosion products. On sample drying the unstable green rusts is converted into more stable phases such as goethite and lepidocrocite, while the content of magnetite and siderite decreases. Three types of green rusts in wet materials sampled from tubercles are identified. Unexpectedly, in almost all corrosion scale samples significant amounts of the least stable green rust in chloride form was detected. Analysis of corrosion products suspended in steady water, which remained between tubercles and possibly in their interiors, revealed complex crystallographic composition of the sampled material. Goethite, lepidocrocite and magnetite as well as low amounts of siderite and quartz were present in all samples. Six different forms of green rusts were identified in the deposits separated from steady waters and the most abundant was carbonate green rust GR(CO(3)(2-))(I).

  13. Electrochemical Study on Corrosion Inhibition of Copper in Hydrochloric Acid Medium and the Rotating Ring-Disc Voltammetry for Studying the Dissolution

    Directory of Open Access Journals (Sweden)

    A. K. Satpati

    2011-01-01

    Full Text Available Dissolution characteristics of copper in hydrochloric acid medium and the effect of 4-amino 1,2,4-triazole (ATA on the corrosion process have been studied using conventional electrochemical techniques and rotating ring-disc electrodes (RRDEs. Corrosion potential (corr and corrosion current density (corr were obtained by Tafel extrapolation methods. Charge transfer resistance (ct and double-layer capacitance (dl were obtained from the electrochemical impedance spectroscopy (EIS. ATA was shown to be an effective inhibitor for the copper-corrosion inhibition in acid medium. The corrosion rate was retarded in presence of inhibitors mainly because of the adsorption of the inhibitor on the electrode surface. Adsorption of the inhibitor on the metal surface was found to follow the Langmuir adsorption isotherm. Standard free energy change of the adsorption process (Δ0ad was calculated to be −54.3 kJ mol−1; such a large negative value of Δ0ad suggests the prescence of a chemisorption process.

  14. Corrosion behavior of Haynes {sup registered} 230 {sup registered} nickel-based super-alloys for integrated coal gasification combined cycle syngas plants. A plant exposure study

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sungkyu; Lee, Jieun; Kang, Suk-Hwan; Lee, Seung-Jong; Yun, Yongseung [Institute for Advanced Engineering (IAE), Gyeonggi-do (Korea, Republic of). Plant Engineering Center; Kim, Min Jung [Sungkyunkwan Univ, Gyeonggi-do (Korea, Republic of). Advanced Materials Technology Research Center

    2015-07-01

    The corrosion behavior of commercially available Haynes {sup registered} 230 {sup registered} nickel-based alloy samples was investigated by exposure to coal-gasifying integrated coal gasification combined cycle pilot plant facilities affiliated with the Institute for Advanced Engineering (2.005 MPa and 160-300 C). The morphological and microstructural analyses of the exposed samples were conducted using scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis on the external surface of the recovered corrosion test samples to obtain information of the corrosion scale. These analyses based on the pre- and post-exposure corrosion test samples combined with thermodynamic Ellingham-Pourbaix stability diagrams provided preliminary insight into the mechanism of the observed corrosion behavior prevailing in the piping materials that connected the particulate removal unit and water scrubber of the integrated coal gasification combined cycle pilot plant. Uniform material wastage was observed after 46 hours of operation, and a preliminary corrosion mechanism was suggested: the observed material waste and corrosion behavior of the Haynes {sup registered} 230 {sup registered} nickel-based alloy samples cut off from the coal syngas integrated coal gasification combined cycle plant were explained by the formation of discontinuous (complex) oxide phases and subsequent chlorine-induced active oxidation under the predominantly reducing environment encountered. This contribution continues the already published studies of the Fe-Ni-Cr-Co alloy Haynes {sup registered} 556 {sup registered}.

  15. Combining hydrogen evolution and corrosion data - A case study on the economic viability of selected metal cathodes in microbial electrolysis cells

    Science.gov (United States)

    Brown, Robert Keith; Schmidt, Ulrike Christiane; Harnisch, Falk; Schröder, Uwe

    2017-07-01

    In this study, hydrogen evolution reaction (HER) catalytic and corrosion data is determined for selected metal cathode materials. The HER data was gathered using cyclic voltammetry (CV) in electrolytes with several pH values and varying current densities. Of the tested materials, the stainless steel alloy EN 1.4401/AISI 316 generally had the lowest HER overpotentials at the pH values 0.25, 7 and 9. At the higher pH values of 11 and 14 a custom NiMoFe alloy with a m/m% composition of 60-30-10 showed the lowest overpotentials. After each CV experiment, the electrolyte solution was analyzed to determine the corrosion of the metal cathodes. Results of corrosion measurements showed that the stainless steels EN 1.4401 had the lowest corrosion losses on average across all tested pH values. Combining HER and corrosion data revealed that: In the pH 9 electrolyte solution, EN 1.4401 was not always the best catalyst in terms of its overpotential, but it incurs the least material costs due to its lack of corrosion, this balance thereby making it the ;best choice; under the given conditions. The combination of HER and corrosion data provides a more effective framework for discussing economic viability than either data set alone.

  16. Electrochemical and conversion electron Moessbauer study of corrosion induced by acid rain

    Energy Technology Data Exchange (ETDEWEB)

    Vertes, C.; Lakatos-Varsanyi, M.; Vertes, A. (Dept. of Physical Chemistry and of Nuclear Chemistry, Eoetvoes Univ., Budapest (Hungary)); Meisel, W.; Guetlich, P. (Inst. of Inorganic Chemistry and Analytical Chemistry, Univ. Mainz (Germany))

    1993-04-01

    The passivation of low carbon steel was studied in aqueous solution of 0.5M Na[sub 2]SO[sub 4]+0.001M NaHSO[sub 3] (pH 3.5, 6.5 and 8.5) which can be considered as a model of acid rain. The used conversion electron Moessbauer spectroscopy (CEMS) with the complementary electrochemical investigations proved that the sulfite ions induce pitting corrosion at pH 3.5 and 6.5, while the measurements showed much weaker pitting at pH 8.5. The compositions and thicknesses of the passive films formed during the electrochemical treatments are determined from the CEM spectra. Only [gamma]-FeOOH was found on the surface of the samples at pH 6.5 and 8.5. Nevertheless, at pH 3.5 the sextet belonging to Fe[sub 3]C appears in the spectra, and also FeSO[sub 4].H[sub 2]O could be detected in low concentration. (orig.).

  17. Utilizing various test methods to study the stress corrosion behavior of Al-Li-Cu alloys

    Science.gov (United States)

    Pizzo, P. P.; Galvin, R. P.; Nelson, H. G.

    1984-01-01

    Recently, much attention has been given to aluminum-lithium alloys because of rather substantial specific-strength and specific-stiffness advantages offered over commercial 2000and 7000-series aluminum alloys. An obstacle to Al-Li alloy development has been inherent limited ductility. In order to obtain a more refined microstructure, powder metallurgy (P/M) has been employed in alloy development programs. As stress corrosion (SC) of high-strength aluminum alloys has been a major problem in the aircraft industry, the possibility of an employment of Al-Li alloys has been considered, taking into account a use of Al-Li-Cu alloys. Attention is given to a research program concerned with the evaluation of the relative SC resistance of two P/M processed Al-Li-Cu alloys. The behavior of the alloys, with and without an addition of magnesium, was studied with the aid of three test methods. The susceptibility to SC was found to depend on the microstructure of the alloys.

  18. Studies on the inhibition of mild steel corrosion in hydrochloric acid solution by atenolol drug

    Directory of Open Access Journals (Sweden)

    G. Karthik

    2016-06-01

    Full Text Available The inhibition performance of atenolol on mild steel in 1 M hydrochloric acid solution was studied by weight loss and electrochemical methods. The results show the inhibition efficiency was found to increase with increasing the concentration of the inhibitor from 50 to 300 ppm. The maximum inhibition efficiency 93.8% was observed in the presence of 300 ppm inhibitor (in case of potentiodynamic polarization. The inhibition action of atenolol was explained in terms of adsorption on the mild steel surface. The adsorption process follows Langmuir isotherm via physical adsorption. Electrochemical Impedance spectroscopic technique (EIS exhibits one capacitive loop indicating that, the corrosion reaction is controlled by charge transfer process. Polarization measurements showed that the inhibitor is of a mixed type. The results obtained from the different methods are in good agreement. The surface morphologies of mild steel were examined by Fourier-transform infrared (FT-IR spectroscopy, scanning electron microscope (SEM. Further, the computational calculations are performed to find a relation between their electronic and structural properties.

  19. Moessbauer study of the composition and corrosion behaviour of electrodeposited and cast brass containing 1-4 m% tin

    Energy Technology Data Exchange (ETDEWEB)

    Vertes, A.; Suba, M.; Varsanyi-Lakatos, M.; Czako-Nagy, I. (Eoetvoes Lorand Tudomanyegyetem, Budapest (Hungary). Fizikai Kemiai es Radiologiai Tanszek); Pchelnikov, A.P.; Losev, V.V. (AN SSSR, Moscow. Inst. Fizicheskoj Khimii)

    1982-09-06

    Moessbauer measurements on electrodeposited and cast brass containing 1-4 m% tin were carried out using conversion electron detector. It was found that the tin formed phases with copper but not with zinc. The identified phases were ..beta.., ..gamma.., epsilon and eta and their ratio depended on the tin concentration and on the preparation process of the brass. The corrosion behaviour of the samples was also studied.

  20. Study on Low Corrosion Gel Breaker%低腐蚀破胶剂的研究

    Institute of Scientific and Technical Information of China (English)

    陆原; 任奕; 王仲广; 逯学朝; 郭海军; 王铁钢

    2014-01-01

    An compound corrosion inhibitor BHH-DRH1 was developed in order to solve corrosion problem of oxidative gel breaker. It can be show that the inhibitor can decrease effectively corrosion of gel breaker JPC in laboratory test. It was suggested that the content of inhibitor was 1%. The technology was trialed in offshore oilfield, and the trial result reached expected effect.%针对氧化类的破胶剂引起的腐蚀问题,研究开发了一种复合型缓蚀剂BHH-DRH1,通过室内评价认为其很好地抑制了破胶剂JPC的腐蚀,推荐现场加注量为1.0%。该技术在南海某油田进行试用,取得了预期效果。

  1. Study of localized corrosion in aluminum alloys by the scanning reference electrode technique

    Science.gov (United States)

    Danford, M. D.

    1995-01-01

    Localized corrosion in 2219-T87 aluminum (Al) alloy, 2195 aluminum-lithium (Al-Li) alloy, and welded 2195 Al-Li alloy (4043 filler) have been investigated using the relatively new scanning reference electrode technique (SRET). Anodic sites are more frequent and of greater strength in the 2195 Al-Li alloy than in the 2219-T87 Al alloy, indicating a greater tendency toward pitting for the latter. However, the overall corrosion rates are about the same for these two alloys, as determined using the polarization resistance technique. In the welded 2195 Al-Li alloy, the weld bean is entirely cathodic, with rather strongly anodic heat affected zones (HAZ) bordering both sides, indicating a high probability of corrosion in the HAZ parallel to the weld bead.

  2. Study on Corrosion Mechanism Between MgO-CaO Refractories and Slag

    Institute of Scientific and Technical Information of China (English)

    YU Yanwen; WANG Ning

    2006-01-01

    Magnesia-Calcia materials containing 22- 53wt% CaO have been investigated for refinery slag corrosion and penetration resistance by Scanning Electron Microscopy (SEM) and XRD. The corrosion and penetration resistance of MgO-CaO materials is enhanced with the increase of CaO content in specimens. It can be explained that, with increase of CaO content, the specimens reacted with slag form higher melting point minerals of C3S and C2S, creating a dense surface layer.which stopped others from penetrating further. Thus. the corrosion and penetration resistance was improved. No matter what kinds of slag were chosen, the depth of penetration decreased with increase of CaO content.

  3. Electrochemical Impedance and Modelling Studies of the Corrosion of Three Commercial Stainless Steels in Molten Carbonate

    Directory of Open Access Journals (Sweden)

    C. S. Ni

    2014-01-01

    Full Text Available The corrosion induced by molten carbonates on the metallic structure materials is a problem constraining the life span of molten carbonate fuel cell (MCFC at elevated temperatures. The reaction between the outgrowing oxide scale and lithium carbonate in the electrolyte is generally a slow process and very important to the passivation behaviour of the underlying steel. The corrosion behaviour of three commercial alloys (P92, SS304, and SS310 with different Cr contents in molten (0.62Li, 0.38K2CO3 at 650°C was monitored by electrochemical impedance spectroscopy (EIS for 120 hours to investigate the lithiation process. With SEM images and extensive XRD analysis of the oxides, equivalent circuits were proposed to interpret the impedance data and explain the corrosion behaviour of the three alloys at different stage with respect to lithiation process.

  4. Study of the mechanism action of sodium gluconate used for the protection of scale and corrosion in cooling water system

    Directory of Open Access Journals (Sweden)

    Rachid Touir

    2014-12-01

    Full Text Available This work based on the mechanism action study of sodium gluconate (SG for ordinary mild steel used for cooling water system treatment. In the first time, we evaluated the temperature effect on the scale inhibition of SG using statistic scale inhibition method. Result showed that the inhibition efficiency became more important with increasing temperature, at great concentration (10−2 and 10−3 M. This can be explained by forming of stable complex SG–Ca2+. In the second time, the present work focuses on the study of operational parameters and corrosion products effect on SG performance using potentiodynamic polarization and electrochemical impedance spectroscopic method. The obtained results show that SG is a very good inhibitor for corrosion and scale and remains effective in the presence of corrosion products. For this study we were proposed a mechanism action for SG on metallic surface. In addition, the SG keeps its effectiveness in a more aggressive medium such as 3% NaCl. Finally, to complete the formulation, we added a not oxidizing biocide (CTAB to SG. The results obtained show that SG remains its effective.

  5. A multi-analytical approach to gold in Ancient Egypt: Studies on provenance and corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Tissot, I., E-mail: isabeltissot@gmail.com [LIBPhys – UNL, Faculty of Science and Technology, 2829-516 Caparica (Portugal); Department of Physics, Faculty of Sciences, University of Lisbon, Campo Grande, 1649-004 Lisbon (Portugal); Troalen, L.G. [National Museums Scotland, Collections Services Department, 242 West Granton Road, Edinburgh EH5 1JA (United Kingdom); Manso, M. [LIBPhys – UNL, Faculty of Science and Technology, 2829-516 Caparica (Portugal); Faculdade de Belas-Artes da Universidade de Lisboa, Largo da Academia Nacional de Belas-Artes, 1249-058 Lisbon (Portugal); Ponting, M. [Archaeology, Classics and Egyptology, University of Liverpool, 12-14 Abercromby Square, Liverpool L69 7WZ (United Kingdom); Radtke, M.; Reinholz, U. [BAM Federal Institute for Materials Research and Testing, Richard-Willstaetter-Strasse 11, 12489 Berlin (Germany); Barreiros, M.A. [LNEG, I.P., Estrada do Paço do Lumiar, 22, 1649-038 Lisbon (Portugal); Shaw, I. [Archaeology, Classics and Egyptology, University of Liverpool, 12-14 Abercromby Square, Liverpool L69 7WZ (United Kingdom); Carvalho, M.L. [LIBPhys – UNL, Faculty of Science and Technology, 2829-516 Caparica (Portugal); Guerra, M.F. [ArchAm, UMR 8096 CNRS - Université Paris Sorbonne, MAE, 21 allée de l' Université, 92023 Nanterre (France)

    2015-06-01

    Recent results from a three-year multi-disciplinary project on Ancient Egyptian gold jewellery revealed that items of jewellery from the Middle Kingdom to the New Kingdom were manufactured using a variety of alluvial gold alloys. These alloys cover a wide range of colours and the majority contain Platinum Group Elements inclusions. However, in all the gold foils analysed, these inclusions were found to be absent. In this work a selection of gilded wood and leather items and gold foil fragments, all from the excavations by John Garstang at Abydos (primarily from Middle Kingdom graves), were examined using Scanning Electron Microscopy-Energy Disperse Spectroscopy (SEM-EDS), X-Ray Fluorescence (μXRF), Particle Induced X-Ray Emission (µPIXE) and Double Dispersive X-Ray Fluorescence (D{sup 2}XRF). The work allowed us to characterise the composition of the base-alloys and also to reveal the presence of Pt at trace levels, confirming the use of alluvial gold deposits. Corrosion products were also investigated in the foils where surface tarnish was visually observed. Results showed that the differences in the colour of corrosion observed for the foils are related not only to the thickness of the corrosion layer but also to a multi-layer structure containing the various corrosion products. - Highlights: • Multi-analytical protocol based on techniques with different MDLs and spatial resolution • Application of D{sup 2}XRF developed at synchrotron BESSY II for determination of Pt in Au with a MDL of 1 ppm • Egyptian gold alloys have nanoporous corrosion layers where distinct corrosion phases could be identified. • Egyptian gold foils are made with different gold base alloys, but all containing alluvial gold.

  6. Study on the Applications of Corrosion Inhibitor in Military Aircraft Maintenance%缓蚀剂在军用飞机维护中的应用研究

    Institute of Scientific and Technical Information of China (English)

    孙祚东; 李云仲; 韦利军

    2014-01-01

    Objective To study the validity of the hard film water-displacing corrosion inhibitor which is used in the joint sections of military aircraft in marine environment. Methods The performance of corrosion inhibitor was evaluated through functional penetration test and environment spectrum accelerated corrosion contrast test, and the practical applica-tion effect was verified by the lead probation on typical structure sections of a certain aircraft. Results The penetration rate of the corrosion inhibitor was 85%. The applications of corrosion inhibitor in the military aircraft internal structures could effectively retard the development of corrosion,and postpone the occurrence time of corrosion. Conclusion The applications of corrosion inhibitor in the military aircraft maintenance as an effective means to prevent corrosion is valuable for populari-zation and application.%目的:验证海洋环境下硬膜水置换型缓蚀剂应用于军用飞机连接部位的有效性。方法采用功能渗透性试验、环境谱加速腐蚀对比试验对缓蚀剂性能进行评价,并通过在某型飞机典型结构部位的领先试用验证缓蚀剂的实际应用效果。结果缓蚀剂渗透率可达到85%。应用于军用飞机内部,对腐蚀的发展有明显的抑制作用,可显著延长腐蚀发生的时间。结论应用缓蚀剂作为腐蚀预防的有效手段,可在军用飞机维护中推广应用。

  7. Density functional theory study of ATA, BTAH, and BTAOH as copper corrosion inhibitors: adsorption onto Cu(111) from gas phase.

    Science.gov (United States)

    Kokalj, Anton; Peljhan, Sebastijan

    2010-09-21

    A low-coverage gas-phase adsorption of three corrosion inhibitors-3-amino-1,2,4-triazole (ATA), benzotriazole (BTAH), and 1-hydroxybenzotriazole (BTAOH)-on perfect Cu(111) surface has been studied and characterized using density functional theory calculations. We find that the molecules in neutral form chemisorb weakly to the perfect surface in an upright geometry. The strength of the chemisorption increases in the order BTAH BTA· with the adsorption energies of -1.65, -2.22, and -2.78 eV, respectively. This order is compatible with the trend of experimentally observed corrosion inhibition effectiveness on copper in near-neutral chloride solutions. Although the calculations are performed at the metal/vacuum interface, they provide enough insight to rationalize why in some experiments the BTAH was observed to be adsorbed with an upright geometry and in the others with parallel geometry.

  8. ECLSS Universal Waste Management System (UWMS) Metal Materials Compatibility Study- Electrochemical and Crevice Corrosion Evaluation

    Science.gov (United States)

    Lee, R. E.

    2017-01-01

    Electrochemical and crevice corrosion laboratory test results are presented for three noble metal candidates with possible application on the Universal Waste Management System (UWMS) in support of the Environmental Control and Life Support System (ECLSS) aboard the International Space Station (ISS). The three metal candidates, which included Inconel 625, Hastelloy C276 and Titanium 6Al-4V, were evaluated in two solutions representative of the acidic pretreatment formulations utilized during processing of waste liquids within the ECLSS. Final test results and data analysis indicated that the passive layer on all three metals provides excellent corrosion protection in both solutions under standard test conditions.

  9. Electrochemical impedance study on the corrosion of Al-Pure in hydrochloric acid solution using Schiff bases

    Indian Academy of Sciences (India)

    A S Patel; V A Panchal; N K Shah

    2012-04-01

    The inhibition effect of newly synthesized Schiff bases -benzylidene benzylamine (A) and benzenemethanamine--methyl--(phenylmethylene) (B) on the corrosion behaviour of Al-Pure in 1.0 M HCl was studied using galvanostatic polarization and electrochemical impedance spectroscopy (EIS) and adsorption studies. The effects of inhibitor concentration, temperature and surface coverage are investigated. The effect of inhibitor concentration and other parameters are evaluated for different inhibitor concentrations and the probable mechanism was also proposed. The results show that (A) and (B) possess excellent inhibiting effect for the corrosion of Al-Pure and the inhibitors act as mixed type inhibitors. The inhibitors do not affect the mechanism of the electrode processes and inhibit corrosion by blocking the reaction sites. The high inhibition efficiency of (A) and (B) were due to the adsorption of inhibitor molecules on the metal surface. The decrease of surface area available for electrode reactions to take place is due to the formation of a protective film. Activation energy and free energy of adsorption have been calculated.

  10. Towards lightweight nanocomposite coatings for corrosion inhibition: Graphene, carbon nanotubes, and nanostructured magnesium as case studies

    Science.gov (United States)

    Dennis, Robert Vincent, III

    The field of nanocomposites is a burgeoning area of research due to the interest in the remarkable properties which can be achieved through their use in a variety of applications, including corrosion resistant coatings. Lightweighting is of increasing importance in the world today due to the ever growing push towards energy efficiency and the green movement and in recent years there has been a vast amount of research performed in the area of developing lightweight nanocomposites for corrosion inhibition. Many new composite materials have been developed through the use of newly developed nanomaterials (including carbonaceous and metallic constituents) and their specialized incorporation in the coating matrix materials. We start with a general review on the development of hybrid nanostructured composites for corrosion protection of base metals from a sustainability perspective in Chapter 1. This review demonstrates the ever swelling requirements for a paradigm shift in the way that we protect metals against corrosion due to the costs and environmental concerns that exist with currently used technology. In Chapter 2, we delve into the much required understanding of graphene oxide and reduced graphene oxide through near-edge X-ray absorption fine structure (NEXAFS) spectroscopy measurements to elucidate information about the electronic structure upon incorporation of nitrogen within the structure. For successful integration of the carbonaceous nanomaterials into a composite coating, a full swath of knowledge is necessary. Within this work we have shown that upon chemical defunctionalization of graphene oxide to reduced graphene oxide by means of hydrazine treatment, nitrogen is incorporated into the structure in the form of a pyrazole ring. In Chapter 3, we demonstrate that by way of in situ polymerization, graphene and multiwalled carbon nanotubes can be incorporated within a polymer (polyetherimide, PEI) matrix. Two systems have been developed including graphene and

  11. Development of chloride-induced corrosion in pre-cracked RC beams under sustained loading: Effect of load-induced cracks, concrete cover, and exposure conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Linwen [Université de Toulouse, UPS, INSA, LMDC, Toulouse (France); Université de Sherbrooke, Quebec (Canada); François, Raoul, E-mail: raoul.francois@insa-toulouse.fr [Université de Toulouse, UPS, INSA, LMDC, Toulouse (France); Dang, Vu Hiep [Hanoi Architectural University, Faculty of Civil Engineering, Hanoi (Viet Nam); L' Hostis, Valérie [CEA Saclay, CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, Gif-sur-Yvette (France); Gagné, Richard [Université de Sherbrooke, Quebec (Canada)

    2015-01-15

    This paper deals with corrosion initiation and propagation in pre-cracked reinforced concrete beams under sustained loading during exposure to a chloride environment. Specimen beams that were cast in 2010 were compared to specimens cast in 1984. The only differences between the two sets of beams were the casting direction in relation to tensile reinforcement and the exposure conditions in the salt-fog chamber. The cracking maps, corrosion maps, chloride profiles, and cross-sectional loss of one group of two beams cast in 2010 were studied and their calculated corrosion rates were compared to that of beams cast in 1984 in order to investigate the factors influencing the natural corrosion process. Experimental results show that, after rapid initiation of corrosion at the crack tip, the corrosion process practically halted and the time elapsing before corrosion resumed depended on the exposure conditions and cover depth.

  12. Comparison of electrochemical techniques during the corrosion of X52 pipeline steel in the presence of sulfate reducing bacteria (SRB)

    Energy Technology Data Exchange (ETDEWEB)

    Galvan-Martinez, R.; Genesca, J. [Universidad Nacional Autonoma de Mexico (UNAM), Facultad de Quimica, Depto. de Ingenieria Metalurgica, Ciudad Universitaria. Mexico DF, CP 04510 (Mexico); Garcia-Caloca, G.; Duran-Romero, R.; Mendoza-Flores, J. [Instituto Mexicano del Petroleo, Direccion Ejecutiva de Exploracion y Produccion, Corrosion, Eje Central Lazaro Cardenas 152, Mexico D.F., 07730 (Mexico); Torres-Sanchez, R. [Universidad Michoacana de San Nicolas de Hidalgo, Instituto de Investigaciones, Metalurgicas. Edificio ' ' U' ' , C.U. Morelia, Michoacan (Mexico)

    2005-10-01

    This work compares three electrochemical techniques, linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN), used in the study of corrosion of X52 steel samples in an environment containing a culture of sulfate reducing bacteria (SRB). The study emphasizes the different electrochemical information obtained when using these techniques in microbiologically influenced corrosion (MIC) studies. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  13. Aqueous corrosion behavior of uranium-molybdenum alloys

    Science.gov (United States)

    Gardner, Levi D.

    Nuclear fuel characterization requires understanding of the various conditions to which materials are exposed in-reactor. One of these important conditions is corrosion, particularly that of fuel constituents. Therefore, corrosion behavior is of special interest and an essential part of nuclear materials characterization efforts. In support of the Office of Material Management and Minimization's Reactor Conversion Program, monolithic uranium-10 wt% molybdenum alloy (U-Mo) is being investigated as a low enriched uranium alternative to highly enriched uranium dispersion fuel currently used in domestic high performance research reactors. The aqueous corrosion behavior of U-Mo is being examined at Pacific Northwest National Laboratory (PNNL) as part of U-Mo fuel fabrication capability activity. No prior study adequately represents this behavior given the current state of alloy composition and thermomechanical processing methods, and research reactor water chemistry. Two main measurement techniques were employed to evaluate U-Mo corrosion behavior. Low-temperature corrosion rate values were determined by means of U-Mo immersion testing and subsequent mass-loss measurements. The electrochemical behavior of each processing condition was also qualitatively examined using the techniques of corrosion potential and anodic potentiodynamic polarization. Scanning electron microscopy (SEM) and optical metallography (OM) imagery and hardness measurements provided supplemental corrosion analysis in an effort to relate material corrosion behavior to processing. The processing effects investigated as part of this were those of homogenization heat treatment (employed to mitigate the effects of coring in castings) and sub-eutectoid heat treatment, meant to represent additional steps in fabrication (such as hot isostatic pressing) performed at similar temperatures. Immersion mass loss measurements and electrochemical results both showed very little appreciable difference between

  14. Synergistic effects of additives to benzotriazole solutions applied as corrosion inhibitors to archaeological copper and copper alloy artefacts.

    OpenAIRE

    Golfomitsou, S.

    2006-01-01

    Benzotriazole (BTA) is a corrosion inhibitor extensively used for the stabilisation of active corrosion of archaeological copper and copper alloys. However, BTA often fails to effectively retard corrosion when applied on heavily corroded artefacts. Although there are numerous studies about its mode of action on clean copper, there is no comprehensive understanding about the way it is bonded to corroded copper. This thesis aimed to understand and compare BTA and its mode of action on clean and...

  15. Experimental and theoretical studies on inhibition of mild steel corrosion by some synthesized polyurethane tri-block co-polymers.

    Science.gov (United States)

    Kumar, Sudershan; Vashisht, Hemlata; Olasunkanmi, Lukman O; Bahadur, Indra; Verma, Hemant; Singh, Gurmeet; Obot, Ime B; Ebenso, Eno E

    2016-08-12

    Polyurethane based tri-block copolymers namely poly(N-vinylpyrrolidone)-b-polyurethane-b-poly(N-vinylpyrrolidone) (PNVP-PU) and poly(dimethylaminoethylmethacrylate)-b-polyurethane-b-poly(dimethylaminoethylmethacrylate) (PDMAEMA-PU) were synthesized through atom transfer radical polymerization (ATRP) mechanism. The synthesized polymers were characterized using nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC) methods. The corrosion inhibition performances of the compounds were investigated on mild steel (MS) in 0.5 M H2SO4 medium using electrochemical measurements, surface analysis, quantum chemical calculations and molecular dynamic simulations (MDS). Potentiodynamic polarization (PDP) measurements revealed that the polymers are mixed-type corrosion inhibitors. Electrochemical impedance spectroscopy (EIS) measurements showed that the polymers inhibit MS corrosion by adsorbing on MS surface to form pseudo-capacitive interface. The inhibitive effects of the polymers increase with increasing concentration and decrease with increasing temperature. The adsorption of both the polymers on MS surface obey the Langmuir adsorption isotherm and involves both physisorption and chemisorption mechanisms. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses showed that the polymers formed protective film on MS surface and shield it from direct acid attack. Quantum chemical calculations and molecular dynamic simulations studies corroborate experimental results.

  16. Alternating and direct current electrochemical studies of a wool wax-based corrosion preventive coating on aluminum alloy 2024

    Energy Technology Data Exchange (ETDEWEB)

    Su, P.C.; Devereux, O.F. [Univ. of Connecticut, Storrs, CT (United States). Dept. of Metallurgy and Materials Engineering

    1998-06-01

    The corrosion behavior of Al 2024-T3 treated with a wool wax (lanolin)-based corrosion preventive coating in aqueous 0.5 M sodium chloride was studied using electrochemical impedance spectroscopy (EIS) and direct current electrode polarization. DC measurements were modeled by three reactions: oxidation of aluminum, reduction of oxygen, and reduction of hydrogen. Alternating current behavior of untreated specimens was modeled using the Randles circuit, and that of inhibited specimens was modeled using parallel resistance-capacitance circuits representing the coating and the charge-transfer process. AC and DC estimates of the polarization resistance of coated specimens were 50 M{Omega}-cm{sup 2} and 32 M{Omega}-cm{sup 2}, respectively. AC and DC values for bare control specimens were of the order of 3 k{Omega}-cm{sup 2} and 15 k{Omega}-cm{sup 2}, respectively. The wool wax coating was found to be a very effective corrosion preventative for this alloy in the aqueous saline environment whether applied to freshly prepared surfaces or to corroded specimens removed from simulated service.

  17. Experimental and quantum chemical studies on two triazole derivatives as corrosion inhibitors for mild steel in acid media

    Energy Technology Data Exchange (ETDEWEB)

    Li, W.; Tian, H.; Hou, B. [Key Laboratory of Corrosion Science, Shandong, Institute of Oceanology, Chinese Academy of Sciences, Qingdao (China); Hu, L.; Tao, Z. [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing (China)

    2011-11-15

    Two triazole derivatives [1-phenyl-2-(5-(1,2,4) triazol-1-ylmethyl-(1,3,4) oxadizaol-2-ylsulphanyl)-ethanone (PTOE) and 2-(4-tert-butyl-benzylsulphanyl)-5-(1,2,4) triazol-1-ylmethyl-(1,3,4) oxadiazole (TBTO)] were synthesized as new corrosion inhibitors for the corrosion of mild steel in 1 M hydrochloric acid solutions. The inhibiting efficiency of the different inhibitors was evaluated by means of weight loss and electrochemical techniques such as electrochemical impedance spectroscopy (EIS) and polarization curves. The electrochemical investigation results indicate that these compounds act as mixed-type inhibitors retarding the anodic and cathodic corrosion reactions and do not change the mechanism of either hydrogen evolution reaction or mild steel dissolution. The studied compounds followed the Langmuir adsorption isotherm, and the thermodynamic parameters were determined and discussed. The effect of molecular structure on the inhibition efficiency has been investigated with ab initio calculations. The electronic properties such as highest occupied molecular orbital (HOMO) energy level, lowest unoccupied molecular orbital (LUMO) energy level, dipole moment ({mu}) and molecular orbital densities were calculated. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Experimental and theoretical studies on inhibition of mild steel corrosion by some synthesized polyurethane tri-block co-polymers

    Science.gov (United States)

    Kumar, Sudershan; Vashisht, Hemlata; Olasunkanmi, Lukman O.; Bahadur, Indra; Verma, Hemant; Singh, Gurmeet; Obot, Ime B.; Ebenso, Eno E.

    2016-01-01

    Polyurethane based tri-block copolymers namely poly(N-vinylpyrrolidone)-b-polyurethane-b-poly(N-vinylpyrrolidone) (PNVP-PU) and poly(dimethylaminoethylmethacrylate)-b-polyurethane-b-poly(dimethylaminoethylmethacrylate) (PDMAEMA-PU) were synthesized through atom transfer radical polymerization (ATRP) mechanism. The synthesized polymers were characterized using nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC) methods. The corrosion inhibition performances of the compounds were investigated on mild steel (MS) in 0.5 M H2SO4 medium using electrochemical measurements, surface analysis, quantum chemical calculations and molecular dynamic simulations (MDS). Potentiodynamic polarization (PDP) measurements revealed that the polymers are mixed-type corrosion inhibitors. Electrochemical impedance spectroscopy (EIS) measurements showed that the polymers inhibit MS corrosion by adsorbing on MS surface to form pseudo-capacitive interface. The inhibitive effects of the polymers increase with increasing concentration and decrease with increasing temperature. The adsorption of both the polymers on MS surface obey the Langmuir adsorption isotherm and involves both physisorption and chemisorption mechanisms. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses showed that the polymers formed protective film on MS surface and shield it from direct acid attack. Quantum chemical calculations and molecular dynamic simulations studies corroborate experimental results. PMID:27515383

  19. Experimental and theoretical studies on inhibition of mild steel corrosion by some synthesized polyurethane tri-block co-polymers

    Science.gov (United States)

    Kumar, Sudershan; Vashisht, Hemlata; Olasunkanmi, Lukman O.; Bahadur, Indra; Verma, Hemant; Singh, Gurmeet; Obot, Ime B.; Ebenso, Eno E.

    2016-08-01

    Polyurethane based tri-block copolymers namely poly(N-vinylpyrrolidone)-b-polyurethane-b-poly(N-vinylpyrrolidone) (PNVP-PU) and poly(dimethylaminoethylmethacrylate)-b-polyurethane-b-poly(dimethylaminoethylmethacrylate) (PDMAEMA-PU) were synthesized through atom transfer radical polymerization (ATRP) mechanism. The synthesized polymers were characterized using nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC) methods. The corrosion inhibition performances of the compounds were investigated on mild steel (MS) in 0.5 M H2SO4 medium using electrochemical measurements, surface analysis, quantum chemical calculations and molecular dynamic simulations (MDS). Potentiodynamic polarization (PDP) measurements revealed that the polymers are mixed-type corrosion inhibitors. Electrochemical impedance spectroscopy (EIS) measurements showed that the polymers inhibit MS corrosion by adsorbing on MS surface to form pseudo-capacitive interface. The inhibitive effects of the polymers increase with increasing concentration and decrease with increasing temperature. The adsorption of both the polymers on MS surface obey the Langmuir adsorption isotherm and involves both physisorption and chemisorption mechanisms. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses showed that the polymers formed protective film on MS surface and shield it from direct acid attack. Quantum chemical calculations and molecular dynamic simulations studies corroborate experimental results.

  20. An experimental set-up to apply polarization modulation to infrared reflection absorption spectroscopy for improved in situ studies of atmospheric corrosion processes.

    Science.gov (United States)

    Wiesinger, R; Schade, U; Kleber, Ch; Schreiner, M

    2014-06-01

    A new set-up for improved monitoring of atmospheric corrosion processes in situ and in real-time is presented. To characterize chemical structures of thin films on metal surfaces surface sensitive analytical techniques are required. One possible technique is Infrared Reflection Absorption Spectroscopy (IRRAS) which has become an established method to investigate surface corrosion films of thicknesses less than 200 nm. However, there are limitations related to the sensitivity of these measurements, in case of investigating ultrathin films or absorption bands of interest, surface species are superimposed by atmospheric background absorption, which changes during in situ measurements in ambient atmospheres. These difficulties of in situ surface reflection measurements can be eliminated by availing the polarization selectivity of adsorbed surface species. At grazing angles of incidence the absorption of p-polarized infrared radiation by thin surface films on metals is enhanced, while the absorption of s-polarized light by this film is nearly zero. This different behavior of the polarization properties leads to strong selection rules at the surface and can therefore be used to identify molecules adsorbed on metal surfaces. Polarization Modulation (PM) of the infrared (IR) light takes advantage of this disparity of polarization on sample surfaces and in combination with IRRAS yielding a very sensitive and surface-selective method for obtaining IR spectra of ultra-thin films on metal surfaces. An already existing in situ IRRAS/Quartz Crystal Microbalance weathering cell was combined with PM and evaluated according to its applicability to study in situ atmospheric corrosion processes. First real-time measurements on silver samples exposed to different atmospheres were performed showing the advantage of PM-IRRAS compared to conventional IRRAS for such investigations.

  1. A study on microstructure and corrosion resistance of ZrO2-containing PEO coatings formed on AZ31 Mg alloy in phosphate-based electrolyte

    Science.gov (United States)

    Zhuang, J. J.; Guo, Y. Q.; Xiang, N.; Xiong, Y.; Hu, Q.; Song, R. G.

    2015-12-01

    ZrO2-containing ceramic coatings formed on the AZ31 Mg alloy were fabricated in an alkaline electrolyte containing sodium phosphate and potassium fluorozirconate (K2ZrF6) by plasma electrolytic oxidation (PEO). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) techniques were used to study the phase structure and composition of the coatings. It is indicated that the coatings formed in the K2ZrF6-containing electrolyte were composed of MgO, MgF2 and t-ZrO2. Morphological investigation carried out by scanning electron microscopy (SEM) and stereoscopic microscopy, revealed that the uniformity of coatings increased and roughness of coatings decreased after the addition of K2ZrF6. Electrochemical investigation was achieved by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) test. The results showed that the PEO coating formed in K2ZrF6-containing electrolyte exhibited an improved corrosion resistance than that of the coating formed in K2ZrF6-free electrolyte. In addition, the polarization and EIS tests results both showed that the suitable concentration (2.5 g/l) of K2ZrF6 is of significant ability to improve the corrosion resistance of coatings. However, 5 g/l and 10 g/l K2ZrF6 has a negative effect on improving the corrosion resistance of PEO coatings compared with the coating formed in 2.5 g/l K2ZrF6-containing electrolyte.

  2. A Meta-Analysis Of Corrosion Studies for Maritime Patrol and Reconnaissance Aircraft (MPRA)

    Science.gov (United States)

    2016-09-01

    fleet operators, using inductive and deductive reasoning proposed a different set of actual MPRA corrosion man-hour metrics. As stated in the...Figure 9.  Adapted from Herzberg Preventative vs . Corrective Cost Curve. Source: Herzberg et al. (2011, 1–5...Prevention vs . Treatment Man-Hours. Adapted from Wilson and Ball (2014)..........................................................32  x THIS PAGE

  3. Copper Corrosion in Nuclear Waste Disposal: A Swedish Case Study on Stakeholder Insight

    Science.gov (United States)

    Andersson, Kjell

    2013-01-01

    The article describes the founding principles, work program, and accomplishments of a Reference Group with both expert and layperson stakeholders for the corrosion of copper canisters in a proposed deep repository in Sweden for spent nuclear fuel. The article sets the Reference Group as a participatory effort within a broader context of…

  4. Copper Corrosion in Nuclear Waste Disposal: A Swedish Case Study on Stakeholder Insight

    Science.gov (United States)

    Andersson, Kjell

    2013-01-01

    The article describes the founding principles, work program, and accomplishments of a Reference Group with both expert and layperson stakeholders for the corrosion of copper canisters in a proposed deep repository in Sweden for spent nuclear fuel. The article sets the Reference Group as a participatory effort within a broader context of…

  5. The study of corrosion behavior of laser induced surface improvement (LISI) on steel and aluminum substrates

    Energy Technology Data Exchange (ETDEWEB)

    Lindsey, N.; Vasanth, K.L.

    1999-07-01

    Laser Induced Surface Improvement (LISI) is a new process developed by University of Tennessee Space Institute (UTSI) which employs lasers to melt precursor coatings and portions of the substrate to form a durable corrosion resistant surface. The LISI surface can be tailored to yield a composition that provides minimum impact to the base substrate material while giving good corrosion characteristics. The LISI surface treatment of tungsten carbide was applied on 7075 and 6061 aluminum alloys. The LISI treatment uses a chromium/nickel mixture and a stainless steel type mixture (pseudo stainless steel of 18 wt% chromium, 8 wt% nickel and a trace amount of manganese and silicon) on steel alloy 1010. The corrosion characteristics of these samples were determined in 3.5 wt% NaCl aqueous solution using linear polarization resistance technique. Potentiodynamic scans were run to determine the corrosion rates and optical microscopy was used to examine pitting characteristics of the different surface coatings. The effectiveness of the LISI modified surfaces to protect both steel and aluminum substrates is discussed.

  6. the study of henna leaves extract as green corrosion inhibitor for ...

    African Journals Online (AJOL)

    Chaudhari H.G and Vashi R.T

    2016-05-01

    May 1, 2016 ... Key words: corrosion; mild steel; acetic acid; henna leaves extract; .... The heat of adsorption ∆H°ads can be calculated from the Vant Hoff equation ..... The effect of bitter leaf on the nhibition of mild steel in HCl and H2SO4.

  7. Electrochemical Studies of Corrosion in Liquid Electrolytes for Energy Conversion Applications at Elevated Temperatures

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey Valerievich; Petrushina, Irina; Bjerrum, Niels J.

    2016-01-01

    Stainless steels (AISI 316, 321 and 347), high-nickel alloys (Hasteloy®C-276 and Inconel®625), tantalum, nickel, titanium, tungsten, molybdenum, niobium, platinum, and gold were tested for corrosion resistance in molten KH2PO4 (or KH2PO4-K2H2P2O7) as a promising electrolyte for the intermediate...

  8. Corrosion behavior of nanostructured Ni-Si{sub 3}N{sub 4} composite films: A study of electrochemical impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Li, J.M.; Cai, C.; Xue, M.Z.; Liu, Y.G. [School of Chemistry and Chemical Technology, Shanghai Jiao Tong University, Shanghai (China); Yin, J.Y.; Zhang, Z. [Department of Chemistry, Zhejiang University, Hangzhou (China); Key Laboratory for Light Alloy Materials Technology, JiaXing (China); Li, J.F. [School of Materials Science and Engineering, Central South University, Changsha (China); Yang, J.F. [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University (China)

    2012-07-15

    Ni-Si{sub 3}N{sub 4} nanocomposite films with both the consecutive Ni crystallites and dispersed Si{sub 3}N{sub 4} particles in the nanometer range have been fabricated using DC electroplating technique, and characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD). The corrosion resistance of the Ni-Si{sub 3}N{sub 4} nanocomposite film has been compared to that of pure Ni coating through polarization. Meanwhile, the corrosion process of Ni-Si{sub 3}N{sub 4} nanocomposite film in neutral 3.5% NaCl solution has been investigated using electrochemical impedance spectroscopy (EIS). The results show that the Ni-Si{sub 3}N{sub 4} nanocomposite film is more resistant to corrosion than the pure Ni coating. The corrosion of Ni-Si{sub 3}N{sub 4} nanocomposite film is controlled by electrochemical step, and the whole corrosion process is divided into two sequential stages. The main corrosion type of Ni-Si{sub 3}N{sub 4} nanocomposite films in neutral 3.5% NaCl solution is pitting. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Underground pipeline corrosion

    CERN Document Server

    Orazem, Mark

    2014-01-01

    Underground pipelines transporting liquid petroleum products and natural gas are critical components of civil infrastructure, making corrosion prevention an essential part of asset-protection strategy. Underground Pipeline Corrosion provides a basic understanding of the problems associated with corrosion detection and mitigation, and of the state of the art in corrosion prevention. The topics covered in part one include: basic principles for corrosion in underground pipelines, AC-induced corrosion of underground pipelines, significance of corrosion in onshore oil and gas pipelines, n

  10. Microstructural Modeling of Pitting Corrosion in Steels Using an Arbitrary Lagrangian-Eulerian Method

    Science.gov (United States)

    Yu, Qifeng; Pan, Tongyan

    2017-05-01

    Two microscale numerical models are developed in this work using a moving-mesh approach to investigate the growth process of pitting in different iron phases and the corrosion prevention capability of polyaniline (PANi) on steels. The distributions of corrosion potential and current in the electrolyte-coating-steel system are computed to evaluate the anti-corrosion ability of PANi. The arbitrary Lagrangian-Eulerian approach was used to accomplish the continuous remesh process as was needed to simulate the dynamic growing forefront of the modeled pitting domain. Experimental validation of the numerical models was conducted using the technique of scanning kelvin probe force microscopy (SKPFM). The SKPFM-scanned surface topography and Volta potential difference exhibit comparable results to and thereby prove the numerical results. The potential distribution in the electrolyte phase of the validated models shows that the corrosion pit grows faster in the epoxy-only-coated steel than that in the PANi-primer-coated steel over the simulation time; also, the corrosion pit grows faster in the ferrite phase than in the cementite phase. The simulation results indicate that the epoxy-only coating lost its anti-corrosion capability as the coating was penetrated by electrolyte, while the PANi-based coating can still protect the steel from corrosion after the electrolyte penetration. The models developed in this work can be used to study the mechanisms of pitting corrosion as well as develop more effective corrosion prevention strategies for general metallic materials.

  11. Corrosion behaviour of polished and sandblasted titanium alloys in PBS solution.

    Science.gov (United States)

    Burnat, Barbara; Walkowiak-Przybyło, Magdalena; Błaszczyk, Tadeusz; Klimek, Leszek

    2013-01-01

    In this work, we performed comparative studies of the effect of surface preparation of Ti6Al4V and Ti6Al7Nb biomedical alloys and the influence of endothelial cells on their corrosion behaviour in PBS (Phosphate Buffered Saline). Two different methods of surface modification were applied - polishing and sandblasting. The polished Ti6Al7Nb alloy was found to have the best resistance against general corrosion in PBS. It was characterized by the lowest corrosion rate, the widest passive range and the lowest reactivity. Both alloys prepared by sandblasting exhibited worse corrosion properties in comparison to the polished ones. This can be associated with a greater development of their surface and the presence of Al2O3 grains which caused an increase of corrosion potential but might also influence the weakening of the passive layer. Results of potentiodynamic anodic polarization indicated that more resistant to pitting corrosion was Ti6Al7Nb alloy regardless of the method of surface preparation. In those cases, anodic polarization caused only an increase of passive layer, while in the case of sandblasted Ti6Al4V alloy it caused a pitting corrosion. The results obtained allowed us to conclude that the niobium-titanium alloys had higher corrosion resistance than titanium alloys with vanadium. Moreover, it was stated that endothelial cells improved the corrosion resistance of all the titanium alloys examined.

  12. Microstructural Modeling of Pitting Corrosion in Steels Using an Arbitrary Lagrangian-Eulerian Method

    Science.gov (United States)

    Yu, Qifeng; Pan, Tongyan

    2017-03-01

    Abstracts Two microscale numerical models are developed in this work using a moving-mesh approach to investigate the growth process of pitting in different iron phases and the corrosion prevention capability of polyaniline (PANi) on steels. The distributions of corrosion potential and current in the electrolyte-coating-steel system are computed to evaluate the anti-corrosion ability of PANi. The arbitrary Lagrangian-Eulerian approach was used to accomplish the continuous remesh process as was needed to simulate the dynamic growing forefront of the modeled pitting domain. Experimental validation of the numerical models was conducted using the technique of scanning kelvin probe force microscopy (SKPFM). The SKPFM-scanned surface topography and Volta potential difference exhibit comparable results to and thereby prove the numerical results. The potential distribution in the electrolyte phase of the validated models shows that the corrosion pit grows faster in the epoxy-only-coated steel than that in the PANi-primer-coated steel over the simulation time; also, the corrosion pit grows faster in the ferrite phase than in the cementite phase. The simulation results indicate that the epoxy-only coating lost its anti-corrosion capability as the coating was penetrated by electrolyte, while the PANi-based coating can still protect the steel from corrosion after the electrolyte penetration. The models developed in this work can be used to study the mechanisms of pitting corrosion as well as develop more effective corrosion prevention strategies for general metallic materials.

  13. Corrosion control when using secondary treated municipal wastewater as alternative makeup water for cooling tower systems.

    Science.gov (United States)

    Hsieh, Ming-Kai; Li, Heng; Chien, Shih-Hsiang; Monnell, Jason D; Chowdhury, Indranil; Dzombak, David A; Vidic, Radisav D

    2010-12-01

    Secondary treated municipal wastewater is a promising alternative to fresh water as power plant cooling water system makeup water, especially in arid regions. Laboratory and field testing was conducted in this study to evaluate the corrosiveness of secondary treated municipal wastewater for various metals and metal alloys in cooling systems. Different corrosion control strategies were evaluated based on varied chemical treatment. Orthophosphate, which is abundant in secondary treated municipal wastewater, contributed to more than 80% precipitative removal of phosphorous-based corrosion inhibitors. Tolyltriazole worked effectively to reduce corrosion of copper (greater than 95% inhibition effectiveness). The corrosion rate of mild steel in the presence of free chlorine 1 mg/L (as Cl2) was approximately 50% higher than in the presence of monochloramine 1 mg/L (as Cl2), indicating that monochloramine is a less corrosive biocide than free chlorine. The scaling layers observed on the metal alloys contributed to corrosion inhibition, which could be seen by comparing the mild steel 21-day average corrosion rate with the last 5-day average corrosion rate, the latter being approximately 50% lower than the former.

  14. Sensitivity Analysis of Corrosion Rate Prediction Models Utilized for Reinforced Concrete Affected by Chloride

    Science.gov (United States)

    Siamphukdee, Kanjana; Collins, Frank; Zou, Roger

    2013-06-01

    Chloride-induced reinforcement corrosion is one of the major causes of premature deterioration in reinforced concrete (RC) structures. Given the high maintenance and replacement costs, accurate modeling of RC deterioration is indispensable for ensuring the optimal allocation of limited economic resources. Since corrosion rate is one of the major factors influencing the rate of deterioration, many predictive models exist. However, because the existing models use very different sets of input parameters, the choice of model for RC deterioration is made difficult. Although the factors affecting corrosion rate are frequently reported in the literature, there is no published quantitative study on the sensitivity of predicted corrosion rate to the various input parameters. This paper presents the results of the sensitivity analysis of the input parameters for nine selected corrosion rate prediction models. Three different methods of analysis are used to determine and compare the sensitivity of corrosion rate to various input parameters: (i) univariate regression analysis, (ii) multivariate regression analysis, and (iii) sensitivity index. The results from the analysis have quantitatively verified that the corrosion rate of steel reinforcement bars in RC structures is highly sensitive to corrosion duration time, concrete resistivity, and concrete chloride content. These important findings establish that future empirical models for predicting corrosion rate of RC should carefully consider and incorporate these input parameters.

  15. On the mechanisms of the corrosion of weathering steel by SO{sub 2} in laboratory studies: influence of the environmental parameters

    Energy Technology Data Exchange (ETDEWEB)

    Marco, J. F., E-mail: jfmarco@iqfr.csic.es [Instituto de Química Física “Rocasolano”, CSIC (Spain)

    2017-11-15

    We report here on the mechanisms underlying the corrosion of weathering steel in accelerated laboratory tests using artificially polluted SO{sub 2}-atmospheres. The role of corrosion parameters such as the SO{sub 2} concentration, the exposure time, the relative humidity and temperature of the environment are discussed in detail. Through the extensive use of Mössbauer spectroscopy in both its transmission and electron detection modes, as well as with the help of other analysis techniques, the characterization of the different corrosion products at the various stages of the corrosion process has been carried out. The results complement the data obtained in field studies and help to understand the mechanisms involved in this complex phenomenon.

  16. Corrosion behavior of duplex coatings

    Directory of Open Access Journals (Sweden)

    K. Raghu Ram Mohan Reddy

    2016-07-01

    Full Text Available The titanium alloys are used in defense, aerospace, automobile, chemical plants and biomedical applications due to their very high strength and lightweight properties. However, corrosion is a life-limiting factor when Ti alloys are exposed to different chemical environments at high temperatures. In the present paper, duplex NiCrAlY/WC–Co coating is coated onto Ti6Al4V substrate to investigate the corrosion behavior of both coated samples and the substrate. The duplex coating was performed with NiCrAlY as the intermediate coat of 200 μm thickness deposited by HVOF process and WC–Co ceramic top coat with varying thicknesses of 250 μm, 350 μm and 450 μm deposited by DS process. Potentiodynamic polarization tests were employed to investigate the corrosion performance of duplex coated samples and substrate in Ringer’s solution at 37 °C and pH value was set to 5.7. Finally the results reveal that 350 μm thick coated samples showed highest corrosion resistance compared to 250 μm thick samples as well as bare substrate. However, the 450 μm thick coated sample showed poor corrosion resistance compared to the substrate. The scale formed on the samples upon corrosion was characterized by using SEM analysis to understand the degree of corrosion behavior.

  17. Physics studies in Europe; a comparative study

    NARCIS (Netherlands)

    Steenstrup, S; dalle Rose, LFD; Jones, WG; Tugulea, L; van Steenwijk, FJ

    What are the differences and similarities between physics studies at different universities across Europe (here the definition of Europe is broad)? How much does a student have to work to obtain a degree in physics? Questions like those prompted EUPEN (European Physics Education Network) to make a

  18. Corrosion testing of urea-formaldehyde foam insulating material

    Energy Technology Data Exchange (ETDEWEB)

    Weil, R.; Graviano, A.; Sheppard, K.

    1980-09-01

    Two tests of the corrosiveness of urea-formaldehyde (UF) foam insulating materials were compared. One test, the Timm test, had test coupons foamed in place. In the second, the Canadian test, blocks of foam already set were placed in contact with test coupons. The Timm test uses 10 gage thick coupons, while the Canadian test specifies 3 mil thick ones. Two samples of UF foam were tested by the Timm and the Canadian tests. The electrical-resistance probes showed that the corrosion rate against steel was initially quite high, of the order of 12 to 20 mpy (mils per year). After about 20 days, the rate was almost zero. In the Timm test, the corrosion rates of steel coupons were of the order to 0.5 to 2 mpy when averaged over the 28 or 56 day test period. The greater corrosion rate of the thick coupons in the Canadian test as well as poor reproducibility of the corrosion rates was attributed primarily to variations in the contact areas between the sample and the UF foam. The corrosion rates of galvanized steel coupons in the Canadian test in several cases exceeded the failure value. In the Timm test, the corrosion rates averaged over the whole test period were quite low. The corrosion rates of copper and aluminum in both tests were quite low. On the basis of the results of this study the following recommendations for a corrosion-test procedure for UF foam were made: two corrosion tests should be conducted, one for foam while curing and one after it has stabilized; the Timm test for corrosiveness while curing should be used, but for only 1 to 2 days; the test for corrosiveness after stabilizing should be of the accelerated type such as the Canadian one. To insure a constant-contact area, thicker coupons should be used; and the coupons for both tests should have a controlled part of the area not in contact with the foam to simulate field conditions.

  19. Electrochemical Study of Corrosion Behavior of Wrought Stellite Alloys in Sodium Chloride and Green Death Solutions

    Science.gov (United States)

    Zhang, X. Z.; Liu, R.; Chen, K. Y.; Yao, M. X.; Collier, R.

    2015-09-01

    Corrosion behavior of wrought Stellite 6B and Stellite 6K, which have similar chemical composition but contain different carbon content, in 3.5 wt.% NaCl solution and in Green Death solution is investigated using various electrochemical methods, including potentiodynamic polarization, cyclic polarization, and electrochemical impedance spectroscopy (EIS). The obtained potentiodynamic polarization curves, cyclic polarization curves, and EIS spectra for these alloys are in good agreement, showing that Stellite 6K with higher carbon content is easier corroded due to its larger volume fraction of carbides but the Cr2O3 film formed on this alloy is stronger and more stable than that on Stellite 6B. Further immersion tests on these alloys show that Stellite 6K has less resistance to pitting corrosion.

  20. Corrosion Inhibition Studies of Mild Steel in Acid Medium Using Musa Acuminata Fruit Peel Extract

    Directory of Open Access Journals (Sweden)

    N. Gunavathy

    2012-01-01

    Full Text Available The inhibition effect of unripe fruit peel extract of Musa acuminata (Cultivar variety – Nendran (MNP on corrosion of mild steel in 1 N HCl has been investigated by weight loss and electrochemical impedance spectroscopy (EIS with various concentrations of the extract. The effect of temperature on the corrosion inhibition of mild steel in the temperature range of 30°C – 80°C was carried out. The results indicate that MNP extract act as an effective inhibitor in the acid environment and is of mixed type inhibitor having efficiency as high as 96% at 2% inhibitor concentration. The inhibition efficiency of MNP extract increases with the increase of concentration but decreases with the increase in temperature. The inhibitor achieves its inhibition by physical adsorption of nutrients of the peel extract on the surface of the mild steel. The experimental data revealed that the adsorption occurred according to the Langmuir and Temkin adsorption isotherm.

  1. Studies on the impact, detection, and control of microbiology influenced corrosion related to pitting failures in the Russian oil and gas industry. Final CRADA report.

    Energy Technology Data Exchange (ETDEWEB)

    Ehst, D.

    2006-09-30

    The objectives of the Project are: (1) to design effective anti-corrosion preparations (biocides, inhibitors, penetrants and their combinations) for gas- and oil-exploration industries; (2) to study a possibility of development of environmentally beneficial ('green') biocides and inhibitors of the new generation; (3) to develop chemical and microbiological methods of monitoring of sites at risk of corrosion; and (4) to evaluate potentialities in terms of technology, raw materials and material and technical basis to set up a production of effective anti-corrosion preparations of new generation in Russia. During the four years of the project 228 compounds and formulations were synthesized and studied in respect to their corrosion inhibiting activity. A series of compounds which were according to the Bubble tests more efficient (by a factor of 10-100) than the reference inhibitor SXT-1102, some possessing the similar activity or slightly better activity than new inhibitor ??-1154? (company ONDEO/Nalco). Two synthetic routes for the synthesis of mercaptopyrimidines as perspective corrosion inhibitors were developed. Mercaptopyrimidine derivatives can be obtained in one or two steps from cheap and easily available precursors. The cost for their synthesis is not high and can be further reduced after the optimization of the production processes. A new approach for lignin utilization was proposed. Water-soluble derivative of lignin can by transformed to corrosion protective layer by its electropolymerization on a steel surface. Varying lignosulfonates from different sources, as well as conditions of electrooxidation we proved, that drop in current at high anodic potentials is due to electropolymerization of lignin derivative at steel electrode surface. The electropolymerization potential can be sufficiently decreased by an increase in ionic strength of the growing solution. The lignosulfonate electropolymerization led to the considerable corrosion protection

  2. Studies on the corrosion elecrochemical behavior of nanocrystalline Cr in acidic media%纳米金属Cr在酸性介质中腐蚀电化学行为

    Institute of Scientific and Technical Information of China (English)

    代岚; 王艳; 曹中秋

    2012-01-01

    为探究纳米材料的腐蚀机理,采用机械合金化通过热压制备了纳米金属Cr,并与常规尺寸金属Cr对比研究了其在酸性介质中的腐蚀性能.结果表明:当晶粒尺寸细化到纳米级后,金属Cr腐蚀电流密度增大,耐蚀性能下降;随着酸度的增加,常规尺寸和纳米尺寸金属Cr腐蚀电流密度加大,耐蚀性能下降.两种尺寸金属Cr在中性Na2SO4介质中均出现钝化现象,但常规尺寸金属Cr的钝化区间较宽;常规尺寸金属Cr在加入H+后,钝化减弱,而纳米尺寸金属Cr在加入H+后,钝化现象消失;两种尺寸Cr的交流阻抗谱均呈单容抗弧特征,对纳米材料的应用具有重要意义.%In order to study corrosion mechanisms of nanocrystalline materials, nanocrystalline metal Cr is prepared by mechanical alloying through hot-pressing processes. Its corrosion mechanism and corrosion resistances in acidic media is thus investigated as compared with the corresponding coarse-grained Cr. Results show that with the increment of acid concentration, the corrosion current densities increase and therefore the corrosion resistances decrease. After the grain size is refined, the corrosion current densities of nanocrystalline Cr are larger than those of the corresponding coarse grained materials. This indicates that the corrosion resistances decrease when the grain size is refined. Two kinds of grain size metal Cr produce passive phenomena, but they become weaker with the increment of acid concentration. The electrochemical impedance spectroscopy (EIS) of the two alloys in acidic media is composed of single capacitive loop. This study is of significance for nanocrystalline materials applications.

  3. Draft report: Results of stainless steel canister corrosion studies and environmental sample investigations

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, Charles R. [Sandia National Laboratories, Albuquerque, NM (United States); Enos, David [Sandia National Laboratories, Albuquerque, NM (United States)

    2014-09-01

    This progress report describes work being done at Sandia National Laboratories (SNL) to assess the localized corrosion performance of container/cask materials used in the interim storage of used nuclear fuel. The work involves both characterization of the potential physical and chemical environment on the surface of the storage canisters and how it might evolve through time, and testing to evaluate performance of the canister materials under anticipated storage conditions.

  4. Assessment study of the stresses induced by corrosion in the Advanced Cold Process Canister

    Energy Technology Data Exchange (ETDEWEB)

    Hoch, A.R.; Sharland, S.M. [Chemical Studies Department, Radwaste Disposal Division, AEA Decommissioning and Radwaste, Harwell Laboratory, Oxfordshire (United Kingdom)

    1993-10-01

    The Advanced Cold Process Canister (ACPC) is a concept for the encapsulation of spent nuclear fuel for geological disposal. The basic design of the ACPC consists of an outer oxygen free copper overpack covering a carbon steel inner container. In this report the stresses exerted on the copper overpack as a result of an early failure of the canister and the subsequent corrosion of the steel are calculated. 4 figs, 8 refs, 2 tabs.

  5. Aqueous Corrosion Behavior of Iron aluminide Intermetallics

    Science.gov (United States)

    Sharma, Garima; Singh, P. R.; Sharma, R. K.; Gaonkar, K. B.; Ramanujan, R. V.

    2007-12-01

    Iron aluminide intermetallics based on DO3 ordered structure are being developed for use as structural materials and cladding material for conventional engineering alloys. Aqueous corrosion behavior of iron aluminides has been studied extensively by electrochemical techniques. Studies were carried out on pure Fe (99.9%), Fe-28Al (at.%), Fe-28Al-3Cr (at.%), and AISI SS 304 so as to compare and contrast their behavior in same experimental condition. Polarization behavior under different pH conditions was examined to evaluate their performance in acidic, basic, and neutral solutions. Pitting behavior was also studied in solution containing Cl-1 ions. The stability of the passive film formed was studied by current time transients and potential decay profiles. The presence of 3 at.% Cr in iron aluminides was found to improve the aqueous corrosion resistance and makes it comparable to AISI SS 304.

  6. The Influence Studies in Comparative Literature

    Institute of Scientific and Technical Information of China (English)

    张宏莹

    2010-01-01

    Comparative literature arose in the 19th century,the approach adopted for its influence study has been developed and diversified in different eras,in this article,the influence study in comparative literature through a reading culture is discussed in order to reveal in what aspects the reading culture may cut across the regional border of influence study.

  7. Application of Electrochemical Impedance Spectroscopy in the Evaluation of Corrosion and Cathodic Protection in Reinforced Concrete

    NARCIS (Netherlands)

    Koleva, D.A.; Van Breugel, K.; De Wit, J.H.W.; Fraaij, A.L.A.; Boshkov, N.

    2007-01-01

    The electrochemical behavior of steel reinforcement in conditions of corrosion and cathodic protection (CP) was studied, using electrochemical impedance spectroscopy (EIS) and compared to reference (non-corroding) conditions. Polarization resistance (PR) method and potentio-dynamic polarization (PDP

  8. Investigation of Corrosion and Cathodic Protection in Reinforced Concrete. I: Application of Electrochemical Techniques

    NARCIS (Netherlands)

    Koleva, D.A.; De Wit, J.H.W.; Van Breugel, K.; Lodhi, Z.F.; Van Westing, E.

    2007-01-01

    The electrochemical behavior of steel reinforcement in conditions of corrosion and cathodic protection was studied, using electrochemical impedance spectroscopy (EIS) and compared to reference (noncorroding) conditions. Polarization resistance (PR) method and potentiodynamic polarization (PDP) were

  9. Study on Surface Adsorption and Inhibition Behavior of Corrosion Inhibitors Contained in Copper Foil Rolling Oil

    Institute of Scientific and Technical Information of China (English)

    Xiong Sang; Sun Jianlin; Jiang Wei; Xu Yang; Zeng Yingfeng; Xia Lei

    2015-01-01

    Adsorption and inhibition behavior of 2,5-bis(ethyldisulfanyl)-1,3,4-thiadiazole (DMTDA) andN-((6-methyl-1H -benzo[d][1,2,3]triazol-1-yl)methyl)-N-octyloctan-1-amine (EAMBA) as corrosion inhibitors contained in copper foil roll-ing oil have been investigated using gravimetric and electrochemical techniques. Meanwhile, scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) have been employed to observe the surface topography and analyze the components on copper foil. The results show that the rolling oil containing DMTDA and EAMBA can signiifcantly decrease the dissolution rate and increase the inhibition efifciency of samples, especially in the case of best compounded rolling oil system. The SEM and EDS investigations also conifrmed that the protection of the copper foil surface is achieved by strong adsorption of the molecules which can prevent copper from being corroded easily. Reactivity descriptors of the corrosion inhibitors have been calculated by the density functional theory (DFT) and the reactivity has been analyzed through the molecular orbital and Fukui indices. Active sites of inhibitor are mainly concentrated on the ring and the polar functional groups, and in the meanwhile, the distribution is helpful to form coordination and backbonding among molecules and then to form stable adsorption on the metal surface. And this work provides theoretical evidence for the selection of corrosion inhibitors contained in copper foil rolling oil.

  10. Structure adhesion and corrosion resistance study of tungsten bisulfide doped with titanium deposited by DC magnetron co-sputtering

    Energy Technology Data Exchange (ETDEWEB)

    De La Roche, J. [Laboratorio de Física del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 vía al aeropuerto, Campus La Nubia, Manizales (Colombia); González, J.M. [Laboratorio de Recubrimientos Duros y Aplicaciones Industriales – RDAI, Universidad del Valle, Calle 13 N° 100-00 Ciudadela Meléndez, Cali (Colombia); Restrepo-Parra, E., E-mail: erestrepop@unal.edu.co [Laboratorio de Física del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 vía al aeropuerto, Campus La Nubia, Manizales (Colombia); Sequeda, F. [Laboratorio de Recubrimientos Duros y Aplicaciones Industriales – RDAI, Universidad del Valle, Calle 13 N° 100-00 Ciudadela Meléndez, Cali (Colombia); Alleh, V.; Scharf, T.W. [The University of North Texas, Department of Materials Science and Engineering, Denton, TX 76203 (United States)

    2014-11-30

    Highlights: • Ti-doped WS{sub 2} films were grown via the magnetron co-sputtering technique. • At a high Ti percentage, the crystalline structure of WS{sub 2} coatings tends to be amorphous. • As the Ti percentage increases in WS{sub 2} coatings, nanocomposites tend to form. • Ti-doped WS{sub 2} films have elastic behavior compared with the plastic response of pure WS{sub 2} films. • A high Ti percentage increases the corrosion resistance of WS{sub 2} films. - Abstract: Titanium-doped tungsten bisulfide thin films (WS{sub 2}-Ti) were grown using a DC magnetron co-sputtering technique on AISI 304 stainless steel and silicon substrates. The films were produced by varying the Ti cathode power from 0 to 25 W. Using energy dispersive spectroscopy (EDS), the concentration of Ti in the WS{sub 2} was determined, and a maximum of 10% was obtained for the sample grown at 25 W. Moreover, the S/W ratio was calculated and determined to increase as a function of the Ti cathode power. According to transmission electron microscopy (TEM) results, at high titanium concentrations (greater than 6%), nanocomposite formation was observed, with nanocrystals of Ti embedded in an amorphous matrix of WS{sub 2}. Using the scratch test, the coatings’ adhesion was analyzed, and it was observed that as the Ti percentage was increased, the critical load (Lc) also increased. Furthermore, the failure type changed from plastic to elastic. Finally, the corrosion resistance was evaluated using the electrochemical impedance spectroscopy (EIS) technique, and it was observed that at high Ti concentrations, the corrosion resistance was improved, as Ti facilitates coating densification and generates a protective layer.

  11. Nodular Corrosion Characteristics of Zirconium Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Gil; Jeong, Y. H.; Park, S. Y.; Lee, D. J

    2003-01-15

    This study was reported the effect of the nodular corrosion on the nuclear reactor environmental along with metallurgical influence, also suggested experimental scheme related to evaluate nodular corrosion characteristics of Zr-1 Nb alloy. Remedial strategies against the nodular corrosion should firstly develop plan to assess the effect of the water quality condition (Oxygen, Hydrogen) as well as the boiling on the nodular corrosion, secondarily establish plan to control heat treatment process to keep a good resistance on nodular corrosion in Zr-1Nb alloy as former western reactor did.

  12. Analyses of containment structures with corrosion damage

    Energy Technology Data Exchange (ETDEWEB)

    Cherry, J.L.

    1996-12-31

    Corrosion damage to a nuclear power plant containment structure can degrade the pressure capacity of the vessel. For the low-carbon, low- strength steels used in containments, the effect of corrosion on material properties is discussed. Strain-to-failure tests, in uniaxial tension, have been performed on corroded material samples. Results were used to select strain-based failure criteria for corroded steel. Using the ABAQUS finite element analysis code, the capacity of a typical PWR Ice Condenser containment with corrosion damage has been studied. Multiple analyses were performed with the locations of the corrosion the containment, and the amount of corrosion varied in each analysis.

  13. Microbial fouling and corrosion of carbon steel in deep anoxic alkaline groundwater.

    Science.gov (United States)

    Rajala, Pauliina; Bomberg, Malin; Vepsäläinen, Mikko; Carpén, Leena

    2017-02-01

    Understanding the corrosion of carbon steel materials of low and intermediate level radioactive waste under repository conditions is crucial to ensure the safe storage of radioactive contaminated materials. The waste will be in contact with the concrete of repository silos and storage containers, and eventually with groundwater. In this study, the corrosion of carbon steel under repository conditions as well as the microbial community forming biofilm on the carbon steel samples, consisting of bacteria, archaea, and fungi, was studied over a period of three years in a groundwater environment with and without inserted concrete. The number of biofilm forming bacteria and archaea was 1,000-fold lower, with corrosion rates 620-times lower in the presence of concrete compared to the natural groundwater environment. However, localized corrosion was detected in the concrete-groundwater environment indicating the presence of local microenvironments where the conditions for pitting corrosion were favorable.

  14. Corrosion Testing Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Corrosion Testing Facility is part of the Army Corrosion Office (ACO). It is a fully functional atmospheric exposure site, called the Corrosion Instrumented Test...

  15. Quinoxaline derivatives as corrosion inhibitors for mild steel in hydrochloric acid medium: Electrochemical and quantum chemical studies

    Science.gov (United States)

    Olasunkanmi, Lukman O.; Kabanda, Mwadham M.; Ebenso, Eno E.

    2016-02-01

    The corrosion inhibition potential of four quinoxaline derivatives namely, 1-[3-(4-methylphenyl)-5-(quinoxalin-6-yl)-4,5-dihydropyrazol-1-yl]butan-1-one (Me-4-PQPB), 1-(3-(4-methoxyphenyl)-5-(quinoxalin-6-yl)-4,5-dihydropyrazol-1-yl)butan-1-one (Mt-4-PQPB), 1-[3-(3-methoxyphenyl)-5-(quinoxalin-6-yl)-4,5-dihydropyrazol-1-yl]butan-1-one (Mt-3-PQPB) and 1-[3-(2H-1,3-benzodioxol-5-yl)-5-(quinoxalin-6-yl)-4,5-dihydropyrazol-1-yl]butan-1-one (Oxo-1,3-PQPB) was studied for mild steel corrosion in 1 M HCl solution using electrochemical, spectroscopic techniques and quantum chemical calculations. The results of both potentiodynamic polarization and electrochemical impedance spectroscopic studies revealed that the compounds are mixed-type inhibitors and the order of corrosion inhibition efficiency at 100 ppm is Me-4-PQPB>Mt-3-PQPB>Oxo-1,3-PQPB>Mt-4-PQPB. Fourier transform infrared (FTIR) and ultraviolet-visible (UV-vis) spectroscopic analyses confirmed the presence of chemical interactions between the inhibitors and mild steel surface. The adsorption of the inhibitor molecules on mild steel surface was found to be both physisorption and chemisorption but predominantly chemisorption. The experimental data obey Langmuir adsorption isotherm. Scanning electron microscopy studies revealed the formation of protective films of the inhibitors on mild steel surface. Quantum chemical parameters obtained from density functional theory (DFT) calculations support experimental results.

  16. Companion Study Guide to Short Course on Geothermal Corrosion and Mitigation in Low Temperature Geothermal Heating Systems

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, P.F. II

    1985-04-24

    The economic utilization of geothermal resources with temperatures less than 220 degrees Fahrenheit for purposes other than electric power generation (direct utilization) requires creation of systems with long plant life and minimum operation and maintenance costs. Development of such systems requires careful corrosion engineering if the most cost effective material selections and design choices are to be made. This study guide presents guidelines for materials selection for low-temperature geothermal systems (120 - 200 degrees Fahrenheit), as well as guidance in materials design of heat pump systems for very-lowtemperature geothermal resources (less than 120 degrees Fahrenheit). This guideline is divided into five sections and an Appendix.

  17. Quantum chemical study of the inhibition of the corrosion of mild steel in H2SO4 by some antibiotics.

    Science.gov (United States)

    Eddy, Nnabuk O; Ibok, Udo J; Ebenso, Eno E; El Nemr, Ahmed; El Ashry, El Sayed H

    2009-09-01

    The inhibition efficiency of some antibiotics against mild steel corrosion was studied using weight loss and quantum chemical techniques. Values of inhibition efficiency obtained from weight loss measurements correlated strongly with theoretical values obtained through semi empirical calculations. High correlation coefficients were also obtained between inhibition efficiency of the antibiotics and some quantum chemical parameters, including frontier orbital (E (HOMO) and E (LUMO)), dipole moment, log P, TNC and LSER parameters (critical volume and dipolar-polarisability factor), which indicated that these parameters affect the inhibition efficiency of the compounds. It was also found that quantitative structure activity relation can be used to adequately predict the inhibition effectiveness of these compounds.

  18. Microbially induced corrosion of carbon steel in deep groundwater environment

    Directory of Open Access Journals (Sweden)

    Pauliina eRajala

    2015-07-01

    Full Text Available The metallic low and intermediate level radioactive waste generally consists of carbon steel and stainless steels. The corrosion rate of carbon steel in deep groundwater is typically low, unless the water is very acidic or microbial activity in the environment is high. Therefore, the assessment of microbially induced corrosion of carbon steel in deep bedrock environment has become important for evaluating the safety of disposal of radioactive waste. Here we studied the corrosion inducing ability of indigenous microbial community from a deep bedrock aquifer. Carbon steel coupons were exposed to anoxic groundwater from repository site 100 m depth (Olkiluoto, Finland for periods of three and eight months. The experiments were conducted at both in situ temperature and room temperature to investigate the response of microbial population to elevated temperature. Our results demonstrate that microorganisms from the deep bedrock aquifer benefit from carbon steel introduced to the nutrient poor anoxic deep groundwater environment. In the groundwater incubated with carbon steel the planktonic microbial community was more diverse and 100-fold more abundant compared to the environment without carbon steel. The betaproteobacteria were the most dominant bacterial class in all samples where carbon steel was present, whereas in groundwater incubated without carbon steel the microbial community had clearly less diversity. Microorganisms induced pitting corrosion and were found to cluster inside the corrosion pits. Temperature had an effect on the species composition of microbial community and also affected the corrosion deposits layer formed on the surface of carbon steel.

  19. Some Phthalocyanine and Naphthalocyanine Derivatives as Corrosion Inhibitors for Aluminium in Acidic Medium: Experimental, Quantum Chemical Calculations, QSAR Studies and Synergistic Effect of Iodide Ions

    Directory of Open Access Journals (Sweden)

    Masego Dibetsoe

    2015-08-01

    Full Text Available The effects of seven macrocyclic compounds comprising four phthalocyanines (Pcs namely 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine (Pc1, 2,3,9,10,16,17,23,24-octakis(octyloxy-29H,31H-phthalocyanine (Pc2, 2,9,16,23-tetra-tert-butyl-29H,31H-phthalocyanine (Pc3 and 29H,31H-phthalocyanine (Pc4, and three naphthalocyanines namely 5,9,14,18,23,27,32,36-octabutoxy-2,3-naphthalocyanine (nPc1, 2,11,20,29-tetra-tert-butyl-2,3-naphthalocyanine (nPc2 and 2,3-naphthalocyanine (nP3 were investigated on the corrosion of aluminium (Al in 1 M HCl using a gravimetric method, potentiodynamic polarization technique, quantum chemical calculations and quantitative structure activity relationship (QSAR. Synergistic effects of KI on the corrosion inhibition properties of the compounds were also investigated. All the studied compounds showed appreciable inhibition efficiencies, which decrease with increasing temperature from 30 °C to 70 °C. At each concentration of the inhibitor, addition of 0.1% KI increased the inhibition efficiency compared to the absence of KI indicating the occurrence of synergistic interactions between the studied molecules and I− ions. From the potentiodynamic polarization studies, the studied Pcs and nPcs are mixed type corrosion inhibitors both without and with addition of KI. The adsorption of the studied molecules on Al surface obeys the Langmuir adsorption isotherm, while the thermodynamic and kinetic parameters revealed that the adsorption of the studied compounds on Al surface is spontaneous and involves competitive physisorption and chemisorption mechanisms. The experimental results revealed the aggregated interactions between the inhibitor molecules and the results further indicated that the peripheral groups on the compounds affect these interactions. The calculated quantum chemical parameters and the QSAR results revealed the possibility of strong interactions between the studied inhibitors and metal surface. QSAR

  20. Some Phthalocyanine and Naphthalocyanine Derivatives as Corrosion Inhibitors for Aluminium in Acidic Medium: Experimental, Quantum Chemical Calculations, QSAR Studies and Synergistic Effect of Iodide Ions.

    Science.gov (United States)

    Dibetsoe, Masego; Olasunkanmi, Lukman O; Fayemi, Omolola E; Yesudass, Sasikumar; Ramaganthan, Baskar; Bahadur, Indra; Adekunle, Abolanle S; Kabanda, Mwadham M; Ebenso, Eno E

    2015-08-28

    The effects of seven macrocyclic compounds comprising four phthalocyanines (Pcs) namely 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine (Pc1), 2,3,9,10,16,17,23,24-octakis(octyloxy)-29H,31H-phthalocyanine (Pc2), 2,9,16,23-tetra-tert-butyl-29H,31H-phthalocyanine (Pc3) and 29H,31H-phthalocyanine (Pc4), and three naphthalocyanines namely 5,9,14,18,23,27,32,36-octabutoxy-2,3-naphthalocyanine (nPc1), 2,11,20,29-tetra-tert-butyl-2,3-naphthalocyanine (nPc2) and 2,3-naphthalocyanine (nP3) were investigated on the corrosion of aluminium (Al) in 1 M HCl using a gravimetric method, potentiodynamic polarization technique, quantum chemical calculations and quantitative structure activity relationship (QSAR). Synergistic effects of KI on the corrosion inhibition properties of the compounds were also investigated. All the studied compounds showed appreciable inhibition efficiencies, which decrease with increasing temperature from 30 °C to 70 °C. At each concentration of the inhibitor, addition of 0.1% KI increased the inhibition efficiency compared to the absence of KI indicating the occurrence of synergistic interactions between the studied molecules and I(-) ions. From the potentiodynamic polarization studies, the studied Pcs and nPcs are mixed type corrosion inhibitors both without and with addition of KI. The adsorption of the studied molecules on Al surface obeys the Langmuir adsorption isotherm, while the thermodynamic and kinetic parameters revealed that the adsorption of the studied compounds on Al surface is spontaneous and involves competitive physisorption and chemisorption mechanisms. The experimental results revealed the aggregated interactions between the inhibitor molecules and the results further indicated that the peripheral groups on the compounds affect these interactions. The calculated quantum chemical parameters and the QSAR results revealed the possibility of strong interactions between the studied inhibitors and metal surface. QSAR analysis on the

  1. Corrosion resistance of Al-based coatings in flowing Pb–15.7Li produced by aluminum electrodeposition from ionic liquids

    Directory of Open Access Journals (Sweden)

    Sven-Erik Wulf

    2016-12-01

    Full Text Available Reduced activation ferritic–martensitic steels are intended to serve as structural materials in different blanket designs, e.g. HCLL, DCLL and WCLL. In these designs the material is supposed to be in direct contact with the flowing liquid breeder material Pb–15.7Li at an operating temperature of up to 550°C. These conditions will lead to severe corrosion attack of the steel and high corrosion rates of up to 400µm per year are reported in the literature. To avoid or reduce corrosion Al-based corrosion barriers were developed in the last years by using electrochemical techniques to deposit aluminum. Until now two processes have been developed. The first one, so called ECA process, is based on volatile toluene electrolytes. Long-term corrosion experiments on these coatings indicated reduced corrosion rates compared to bare Eurofer steel in flowing Pb–15.7Li. However, these Fe–Al scales showed inhomogeneous corrosion attack of the corrosion barrier itself. In this study the improved ECX process was applied to produce Al-based coatings. The short-term corrosion behavior of such barrier coatings was analyzed for up to 4000h by diameter measurements and metallographic examinations. The investigation revealed uniform corrosion in comparison to inhomogeneous attack in case of ECA coated samples and reduced corrosion rates of around 20µm/a even for low exposure times of 4000h.

  2. Effect of heat treatment on corrosion behavior of duplex coatings

    Directory of Open Access Journals (Sweden)

    K. Raghu Ram Mohan Reddy

    2017-01-01

    Full Text Available In the present paper, duplex WC-Co/NiCrAlY coating is coated onto Ti6Al4V substrate and vacuum heat treatment is employed to investigate the corrosion behavior of heat treated samples as well as Ti6Al4V substrate for comparison. In this duplex coating system, High Velocity Oxy Fuel (HVOF process is used to deposit NiCrAlY interlayer with a constant thickness of 200 μm and WC-Co ceramic top layer with varying thickness of 250 μm, 350 μm and 450 μm deposited by Detonation Spray (DS process. Different heat treatment temperatures (600–1150 °C were employed for the coated samples to study the microstructure and the effect on corrosion resistance of the duplex coatings. Potentiodynamic polarization tests were carried to investigate the corrosion performance of duplex coated heat treated samples and the substrate in Ringer’s solution at 37 °C and prepared the pH to 5.7. The microstructure upon corrosion after heat treatment was characterized by SEM analysis to understand the corrosion behavior. The results disclosed that at all heat treatment temperatures, all the coated samples exhibited better corrosion resistance than the base substrate. However, during 950 °C and 1150 °C heat treatment temperatures, it was observed highest corrosion potential than 600 °C and 800 °C. The 350 μm thickness, coated sample exhibited highest corrosion resistance compared to other two coated samples and the substrate at all heat treatment temperatures.

  3. Results of stainless steel canister corrosion studies and environmental sample investigations

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, Charles R. [Sandia National Laboratories, Albuquerque, NM (United States); Enos, David [Sandia National Laboratories, Albuquerque, NM (United States)

    2014-12-01

    This progress report describes work being done at Sandia National Laboratories (SNL) to assess the localized corrosion performance of container/cask materials used in the interim storage of used nuclear fuel. The work involves both characterization of the potential physical and chemical environment on the surface of the storage canisters and how it might evolve through time, and testing to evaluate performance of the canister materials under anticipated storage conditions. To evaluate the potential environment on the surface of the canisters, SNL is working with the Electric Power Research Institute (EPRI) to collect and analyze dust samples from the surface of in-service SNF storage canisters. In FY 13, SNL analyzed samples from the Calvert Cliffs Independent Spent Fuel Storage Installation (ISFSI); here, results are presented for samples collected from two additional near-marine ISFSI sites, Hope Creek NJ, and Diablo Canyon CA. The Hope Creek site is located on the shores of the Delaware River within the tidal zone; the water is brackish and wave action is normally minor. The Diablo Canyon site is located on a rocky Pacific Ocean shoreline with breaking waves. Two types of samples were collected: SaltSmart™ samples, which leach the soluble salts from a known surface area of the canister, and dry pad samples, which collected a surface salt and dust using a swipe method with a mildly abrasive ScotchBrite™ pad. The dry samples were used to characterize the mineralogy and texture of the soluble and insoluble components in the dust via microanalytical techniques, including mapping X-ray Fluorescence spectroscopy and Scanning Electron Microscopy. For both Hope Creek and Diablo Canyon canisters, dust loadings were much higher on the flat upper surfaces of the canisters than on the vertical sides. Maximum dust sizes collected at both sites were slightly larger than 20 μm, but Phragmites grass seeds ~1 mm in size, were observed on the tops of the Hope Creek canisters

  4. Waste of cleaning emulsion sewage as inhibitors of steel corrosion

    Science.gov (United States)

    Fazullin, D. D.; Mavrin, G. V.; Shaikhiev, I. G.

    2016-06-01

    The article describes the corrosion test of steel of the brand 20 in the stratal water. To increase corrosion resistance as a corrosion inhibitor the concentrate waste emulsion of the mark "Incam- 1" was provided. The article presents studies of the corrosion rate with different dosages of corrosion inhibitor in the stratal water. Based on these research results are revealed that the degree of protection of steel is 27% at a dosage of 3.8 g / dm3.

  5. Experimental and atomistic simulation studies of corrosion inhibition of copper by a new benzotriazole derivative in acid medium

    Energy Technology Data Exchange (ETDEWEB)

    Khaled, K.F. [Electrochemistry Research Laboratory, Chemistry Department, Ain Shams University, Roxy, Cairo 11711 (Egypt)], E-mail: khaledrice2003@yahoo.com

    2009-07-15

    The efficiency of N-(2-thiazolyl)-1H-benzotriazole-1-carbothioamide (TBC) as a non-toxic corrosion inhibitor for copper in 0.5 M HCl has been tested by weight loss and electrochemical techniques. Electrochemical techniques show that TBC is a mixed-type inhibitor and its inhibition mechanism on copper surface is adsorption assisted by H-bond formation. Impedance measurements show a wide peak presumably given by more than one time constant in the presence of TBC. Also, impedance results show that the values of CPEs (constant phase elements) tend to decrease and both polarization resistance and inhibition efficiency tend to increase with increasing of TBC concentration due to an increase in the electric double layer. Monte Carlo simulations incorporating molecular mechanics and molecular dynamics show that the TBC adsorb on the copper surface firmly through the thiazolyl and carbothioamide groups, the adsorption energy as well as hydrogen bond length have been calculated for both TBC and benzotriazole (BTA) for comparison. Quantum chemical calculations reveal that TBC has higher HOMO, lower LUMO, lower energy gap and lower dipole moment ({mu}) than BTA, which proves that TBC is better copper corrosion inhibitor compared with BTA in 0.5 M HCl.

  6. High temperature corrosion studies. A. Iron: based superalloy in SO/sub 2//O/sub 2/ atmospheres. B. Gas: solid reaction with formation of volatile species

    Energy Technology Data Exchange (ETDEWEB)

    Liu, T.K.

    1980-03-01

    The thermogravimetric method was used to study high temperature corrosion under SO/sub 2//O/sub 2/ atmosphere applied to Armco 18SR alloys with different heat treatment histories, Armco T310 and pure chromium between 750 and 1100/sup 0/C. The weight gain follows the parabolic rate law. The volatilization of the protective Cr/sub 2/O/sub 3/ layer via formation of CrO/sub 3/ was taken into account above 900/sup 0/C for long time runs. The parabolic rate and the volatilization rate, derived from fitting the experimental data to the modified Tedmon's non-linear model, were correlated using the Arrhenius equation. Armco 18SR-C has the best corrosion resistance of the Armco 18SR alloys. Armco T310 is not protective at high temperatures. The available rate data on the oxidation of chromium oxide, chlorination of chromium, oxidation-chlorination of chromium oxide, chlorination of nickel and chlorination of iron were found to be predictable. The calculation of high temperature volatilization rate was performed using the available fluid correlation equations and the Lennard-Jones parameters derived from the molecule with similar structure and from the low temperature viscosity measurement. The lower predicted volatilization rate is due to the use of the Chapman-Enskog equation with the Lennard-Jones parameters mostly derived from the low temperature viscosity measurement. This was substantiated by comparing the reliable high temperature diffusion rate in the literature with the above mentioned calculational method. The experimental volatilization rates of this study are compared with the other related studies and the mass transfer predictions.

  7. Lamb-Wave-Based Tomographic Imaging Techniques for Hole-Edge Corrosion Monitoring in Plate Structures

    Directory of Open Access Journals (Sweden)

    Dengjiang Wang

    2016-11-01

    Full Text Available This study presents a novel monitoring method for hole-edge corrosion damage in plate structures based on Lamb wave tomographic imaging techniques. An experimental procedure with a cross-hole layout using 16 piezoelectric transducers (PZTs was designed. The A0 mode of the Lamb wave was selected, which is sensitive to thickness-loss damage. The iterative algebraic reconstruction technique (ART method was used to locate and quantify the corrosion damage at the edge of the hole. Hydrofluoric acid with a concentration of 20% was used to corrode the specimen artificially. To estimate the effectiveness of the proposed method, the real corrosion damage was compared with the predicted corrosion damage based on the tomographic method. The results show that the Lamb-wave-based tomographic method can be used to monitor the hole-edge corrosion damage accurately.

  8. Electrochemical and analytical characterization of three corrosion inhibitors of steel in simulated concrete pore solutions

    Science.gov (United States)

    Shi, Jin-Jie; Sun, Wei

    2012-01-01

    Corrosion inhibitors for steel, such as sodium phosphate (Na3PO4), sodium nitrite (NaNO2), and benzotriazole (BTA), in simulated concrete pore solutions (saturated Ca(OH)2) were investigated. Corrosion behaviors of steel in different solutions were studied by means of corrosion potential ( E corr), linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP). A field emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray analysis (EDXA) was used for observing the microstructures and morphology of corrosion products of steel. The results indicate that, compared with the commonly used nitrite-based inhibitors, Na3PO4 is not a good inhibitor, while BTA may be a potentially effective inhibitor to prevent steel from corrosion in simulated concrete pore solutions.

  9. Effect of high repetition laser shock peening on biocompatibility and corrosion resistance of magnesium

    Science.gov (United States)

    Caralapatti, Vinodh Krishna; Narayanswamy, Sivakumar

    2017-02-01

    Magnesium, as a biomaterial has the potential to replace conventional implant materials owing to its numerous advantages. However, high corrosion rate is a major obstacle that has to be addressed for its implementation as implants. This study aims to evaluate the feasibility and effects of High Repetition Laser Shock Peening (HRLSP) on biocompatibility and corrosion resistance of Mg samples and as well as to analyze the effect of operational parameters such as peening with overlap on corrosion rate. From the results obtained using hydrogen evolution and mass loss methods, it was found that corrosion rates of both 0% overlap and 66% overlap peened samples reduced by more than 50% compared to that of unpeened sample and sample peened with 66% overlap exhibited least corrosion. The biocompatibility of peened Mg samples was also enhanced as there was neither rapid pH variation nor large hydrogen bubble formation around samples.

  10. Evaluation of corrosion behavior of Al-Mg-Li alloys in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Z.; Abdul Aleem, B.J. [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia)

    1996-04-01

    Weldalite 050, a high-strength Al-Mg-Li alloy, was evaluated for its corrosion resistance in deaerated and air saturated Arabian Gulf water to determine its suitability for marine applications. Weight loss and electrochemical studies showed that the alloy had minimum corrosion rates of 1.82 and 4.82 mpy (mils per year), respectively, in deaerated and air saturated Arabian Gulf water with very high total dissolved solids (TDS) content. Weldalite 050 exhibited good resistance to corrosion at velocities up to 3.9 m/s. The formation of Al{sub 2}MgLi, Al-Li, Al{sub 12}Mg{sub 17}, and Al-Li precipitates has a pronounced effect on its corrosion resistance. The corrosion resistance of Weldalite 050 compares favorably with that of alloys 5052 and 5054, wrought alloys 6061 and 6013, and silicon carbide (SiC) reinforced alloys 6061 and 6013.

  11. Studies on Hot Corrosion of the Microstructurally Different Regions of 2.25Cr-1Mo (T22) Boiler Tube Steel Weldment

    Science.gov (United States)

    Kumar, Ravindra; Tewari, V. K.; Prakash, Satya

    2009-10-01

    This study examines the effect of microstructurally different regions on the hot corrosion of tungsten inert gas weldment in 2.25Cr-1Mo (T22) boiler tube steel. Various regions of weldment were oxidized in molten salt Na2SO4-60% V2O5 environment at 900 °C. The base metal was found to oxidize at much higher rates than the weld metal and the heat-affected zone. Oxide scales formed in the three regions were compared by scanning electron microscopy with energy dispersive of X-ray analysis, X-ray diffraction pattern, and electron probe microanalysis. The research investigates the formation of inner scales with free Cr over the HAZ.

  12. Application of Moessbauer spectroscopy to the study of tannins inhibition of iron and steel corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Jaen, Juan A., E-mail: jjaen@ancon.up.ac.pa [Universidad de Panama, CITEN, Depto. de Quimica Fisica (Panama); Obaldia, J. De; Rodriguez, M. V. [Universidad de Panama, Escuela de Quimica, Facultad de Ciencias Naturales, Exactas y Tecnologia (Panama)

    2011-11-15

    The inhibitory effect of tannins was investigated using, among others, potentiodynamic polarizations and Moessbauer spectroscopy. These techniques confirmed that the nature, pH and concentration of tannic solution are of upmost importance in the inhibitory properties of the solutions. It is observed that at low tannin concentration or pH, both, hydrolizable and condensed tannins, effectively inhibit iron corrosion, due to the redox properties of tannins. At pH Almost-Equal-To 0, Moessbauer spectra of the frozen aqueous solutions of iron(III) with the tannin solutions showed that iron is in the form of a monomeric species [Fe(H{sub 2}O){sub 6}]{sup 3 + }, without coordination with the functional hydroxyl groups of the tannins. The suspended material consisted of amorphous ferric oxide and oxyhydroxides, though with quebracho tannin partly resulted in complex formation and in an iron (II) species from a redox process. Other tannins, such as chestnut hydrolysable tannins, do not complex iron at this low pH. Tannins react at high concentrations or pH (3 and 5) to form insoluble blue-black amorphous complexes of mono-and bis-type tannate complexes, with a relative amount of the bis-ferric tannate generally increasing with pH. Some Fe{sup 2 + } in the form of hydrated polymeric ferrous tannate could be obtained. At pH 7, a partially hydrolyzed ferric tannate complex was also formed. The latter two phases do not provide corrosion protection. Tannin solutions at natural pH react with electrodeposited iron films (approx. 6 {mu}m) to obtain products consisting only on the catecholate mono-complex of ferric tannate. Some aspects of the mechanism of tannins protection against corrosion are discussed.

  13. Field testing results for the strategic petroleum reserve pipeline corrosion control program

    Energy Technology Data Exchange (ETDEWEB)

    Buchheit, R.G.; Maestas, L.M.; Hinkebein, T.E.

    1998-02-01

    Results of two studies conducted as part of the Strategic Petroleum Reserve (SPR) Pipeline Corrosion Control Program are reported. These studies focused on evaluation of rotary-applied concrete materials for internal pipeline protection against the erosive and corrosive effects of flowing brine. The study also included evaluation of liners applied by hand on pipe pieces that cannot be lined by rotary methods. Such pipe pieces include tees, elbows and flanged pipe sections. Results are reported from a corrosion survey of 17 different liner formulations tested at the-Big-Rill SPR Site. Testing consisted of electrochemical corrosion rate measurements made on lined pipe sections exposed, in a test manifold, to flowing SPR generated fluids. Testing also involved cumulative immersion exposure where samples were exposed to static site-generated brine for increasing periods of time. Samples were returned to the laboratory for various diagnostic analyses. Results of this study showed that standard calcium silicate concrete (API RP10E) and a rotary calcium aluminate concrete formulation were excellent performers. Hand-lined pipe pieces did not provide as much corrosion protection. The focus of the second part of the study was on further evaluation of the calcium silicate, calcium aluminate and hand-applied liners in actual SPR equipment and service. It was a further objective to assess the practicality of electrochemical impedance spectroscopy (EIS) for field corrosion monitoring of concrete lined pipe compared to the more well-known linear polarization technique. This study showed that concrete linings reduced the corrosion rate for bare steel from 10 to 15 mils per year to 1 mil per year or less. Again, the hand-applied liners did not provide as much corrosion protection as the rotary-applied liners. The EIS technique was found to be robust for field corrosion measurements. Mechanistic and kinetic corrosion rate data were reliably obtained.

  14. A study of corrosion electrochemical properties of martensite-austenite steel Cr15Ni6Mo

    Energy Technology Data Exchange (ETDEWEB)

    Cihal, V.; Hubackova, J.; Kubelka, J.; Mezanec, K.

    1985-11-01

    The steel Cr15Ni6Mo (UHB 119) exhibits a very satisfactory corrosion resistance. However, its superior passivating ability depends on the heat treatment method used. The use of two-step tempering leads primarily to an improved resistance to reactivation and optimum properties are achieved when the basic matrix contains about 40% stable austenite in fine form. This structural state requires the use of tempering temperatures from 625 to 650/sup 0/C in Step 1, and 525/sup 0/C in Step 2 of tempering.

  15. Mentha pulegium extract as a natural product for the inhibition of corrosion. Part I: electrochemical studies.

    Science.gov (United States)

    Khadraoui, Abdelkader; Khelifa, Abdellah; Boutoumi, Hocine; Hammouti, Belkheir

    2014-01-01

    The inhibitory effect of Mentha pulegium extract (MPE) on steel corrosion in 1 M HCl solution was investigated using potentiodynamic polarisation and electrochemical impedance spectroscopy. The inhibition efficiency of MPE was found to increase with the concentration and reached 88% at 33% (v/v). Polarisation measurements show that the natural extract acted as a mixed inhibitor. The remarkable inhibition efficiency of MPE was discussed in terms of blocking of electrode surface by adsorption of inhibitor molecules through active centres. The adsorption of MPE was found to accord with the Temkin isotherm.

  16. Study of the corrosion products formed on carbon steels in the tropical atmosphere of Panama

    Directory of Open Access Journals (Sweden)

    Jaén, J. A.

    2003-12-01

    Full Text Available Mössbauer spectroscopy and X-ray powder diffraction (in selected samples have been used to characterize corrosion products on carbon steels after atmospheric exposure to the tropical Panamanian locations of Panama and Colon, classified according to ISO 9223 as C3 and C5, respectively. Goethite (α-FeOOH of intermediate particle size (20-100 nm, lepidocrocite (γ-FeOOH, a spinel phase consisting of non-stoichiometric magnetite (Fe3-xO4 and/or maghemite (γ-Fe2O3 and nano-sized particles were identified in the corrosion products. The spinel phase is related to short term atmospheric exposure transforms in time to other corrosion products. The corrosion resistance increased with fraction of goethite following a saturation-type behavior.

    Se caracterizaron los productos de corrosión de aceros al carbono expuestos a las atmósferas tropicales panameñas localizadas en Panamá y Colón, mediante el uso de la espectroscopia Mössbauer y difracción de rayos-X (en muestras seleccionadas. Las atmósferas se clasifican como C3 y C5, respectivamente, de acuerdo a la norma ISO 9223. Se lograron identificar los compuestos goethita (α-FeOOH de tamaño de partícula intermedio (20-100 nm, lepidocrocita (γ-FeOOH, una fase de espinela consistente en magnetita no estequiométrica (Fe3-xO4 y/o maghemita (γ-Fe2O3, y nanopartículas. La fase de espinela se puede correlacionar con exposiciones cortas a la atmósfera, transformándose en el tiempo en otros productos de corrosión. La resistencia a la corrosión se incrementa con la cantidad de goethita siguiendo una conducta de saturación.

  17. Performance Evaluation of CPCs Using Corrosion Sensors - Laboratory and Field Studies

    Science.gov (United States)

    2009-02-04

    Testing ( AET ) chamber for 31 days  Temperature: 30 °C  Relative Humidity: 6 hrs @ 50 % and 6 hrs @ 90 %  Salt spray: 15 sec every other day...Results - Summary CPC Threshold % area corroded Recovery during wet part of cycle Recovery during dry part of cycle First visual sign of...CPC G – 4 pins 20 % No No 2 days 5 days February 4, 2009 14 Army Corrosion Summit, 2009 Clearwater Beach, FL Ranking of CPCs – Visual and Impedance

  18. Rare earth conversion coatings grown on AA6061 aluminum alloys. Corrosion studies

    Energy Technology Data Exchange (ETDEWEB)

    Brachetti S, S. B. [Instituto Tecnologico de Ciudad Madero, Av. 1o. de Mayo y Sor Juana I. de la Cruz, Col. Los Mangos, 89440 Ciudad Madero, Tanaulipas (Mexico); Dominguez C, M. A.; Torres H, A. M.; Onofre B, E. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada - Altamira, Carretera Tampico-Puerto Industrial Altamira Km. 14.5, 89600 Altamira, Tamaulipas (Mexico); De la Cruz H, W., E-mail: mdominguezc@ipn.mx [UNAM, Centro de Nanociencias y Nanotecnologia, Apdo. Postal 2681, 22800 Ensenada, Baja California (Mexico)

    2014-07-01

    The present work is aimed to investigate the corrosion resistance of rare earth protective coatings deposited by spontaneous deposition on AA6061 aluminum alloy substrates. Coatings were deposited from water-based Ce(NO{sub 3}){sub 3} and La(NO{sub 3}){sub 3} solutions by varing parameters such as rare earth solution concentration, bath temperature and immersion time. The values of the Tafel slopes indicate that the cathodic process is favored by concentration polarization rather than activation polarization. Chemical and morphological characterizations of the surface before and after electrochemical evaluations were performed by X-ray photoelectron spectroscopy and scanning electron microscopy. (Author)

  19. Biofouling and corrosion studies. Final report, Part I, May 1, 1976-December 1977

    Energy Technology Data Exchange (ETDEWEB)

    Mahalingam, L. M.

    1978-01-01

    Three sets of biofouling experiments were conducted. Two of these sets were done in the Pacific Ocean at Keahole Point, Hawaii, and one was in the Caribbean at St. Croix, Virgin Islands. Data and results from these experiments are presented and discussed. Heat transfer, biological, and metallurgical measurements are presented. A brief account of the data analysis procedures, and an assessment of the hardware performance are given. Recommendations are made to improve the quality of the current efforts in the OTEC Biofouling, Corrosion and Materials program.

  20. Aircraft Corrosion

    Science.gov (United States)

    1981-08-01

    allowed to dry. The area is then checked for the golden brown color which is produced by the chemical conversion material. If the work area requires...Materials, pp. 258-3074 1968. 41. W. IH. Ailor, "Seven-year exposure at Point leyes , California," "Corrosion in Natural Environments, ASTM STP 558," American... Color Units 3 Turbidity Units 0.7 pH Units 7.6 Temperature OF 76 Sp. Conductivity MMhos 425 B.O.D. (5 days at 206C) 0.2 SjV i;~-- 1201 A .9 8 ~ 8 kl