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Sample records for steel corrosion protection

  1. Guidelines for the Protection of Steel Piles : Corrosive Marine Environment

    Rhodes, Graham

    2011-01-01

    The corrosion of steel is a common phenomenon. In a marine environment, steel is corroded at an accelerated rate due to the atmospheric conditions. To combat this corrosion, steel piles are coated in order to protect them. As a major supplier of steel piles, Rautaruukki Oyj (Ruukki) commissioned this project in order to streamline their coating process. Currently Ruukki supplies a different coating system for almost every job; the aim of the project was to reduce the number of systems used to...

  2. Corrosion protection by sonoelectrodeposited organic films on zinc coated steel.

    Et Taouil, Abdeslam; Mahmoud, Mahmoud Mourad; Lallemand, Fabrice; Lallemand, Séverine; Gigandet, Marie-Pierre; Hihn, Jean-Yves

    2012-11-01

    A variety of coatings based on electrosynthesized polypyrrole were deposited on zinc coated steel in presence or absence of ultrasound, and studied in terms of corrosion protection. Cr III and Cr VI commercial passivation were used as references. Depth profiling showed a homogeneous deposit for Cr III, while SEM imaging revealed good surface homogeneity for Cr VI layers. These chromium-based passivations ensured good protection against corrosion. Polypyrrole (PPy) was also electrochemically deposited on zinc coated steel with and without high frequency ultrasound irradiation in aqueous sodium tartrate-molybdate solution. Such PPy coatings act as a physical barrier against corrosive species. PPy electrosynthesized in silent conditions exhibits similar properties to Cr VI passivation with respect to corrosion protection. Ultrasound leads to more compact and more homogeneous surface structures for PPy, as well as to more homogeneous distribution of doping molybdate anions within the film. Far better corrosion protection is exhibited for such sonicated films. PMID:22516111

  3. Corrosion Protection of Steels by Conducting Polymer Coating

    Toshiaki Ohtsuka

    2012-01-01

    Full Text Available The corrosion protection of steels by conducting polymer coating is reviewed. The conducting polymer such as polyaniline, polypyrrole, and polythiophen works as a strong oxidant to the steel, inducing the potential shift to the noble direction. The strongly oxidative conducting polymer facilitates the steel to be passivated. A bilayered PPy film was designed for the effective corrosion protection. It consisted of the inner layer in which phosphomolybdate ion, PMo12O3−40 (PMo, was doped and the outer layer in which dodecylsulfate ion (DoS was doped. The inner layer stabilized the passive oxide and the outer possessed anionic perm-selectivity to inhibit the aggressive anions such as chloride from penetrating through the PPy film to the substrate steel. By the bilayered PPy film, the steel was kept passive for about 200 h in 3.5% sodium chloride solution without formation of corrosion products.

  4. Inorganic coatings on stainless steel for protection against crevice corrosion

    In order to create protection against crevice corrosion stainless steel test specimens of type 316 steel with various inorganic coatings applied on crevice surfaces were tested for 3-50 months at 25 and 30 degree C in natural seawater containing 0.2-1.5 ppm free chlorine. Various metallic coatings, Ni base alloys with Cr and Mo, Ni with W, pure Ag and pure Mo, as well as ceramic coatings - Cr2O3, TiO2 and Al2O3 - were studied. All the coatings tested, except pure Molybdenum applied by plasma spraying in a max 0.1 mm thick layer were found to promote crevice corrosion of the stainless steel. A significant reduction of the crevice corrosion susceptibility was obtained with Molybdenum. The result is considered promising enough to justify full scale tests in seawater on flange joints of pipes, valves or pumps. (author)

  5. Studies and research work on the reinforcement steel and concrete surface corrosion protection methods

    Gheorghe Croitoru

    2013-01-01

    Methods for reinforcement steel corrosion protection and concrete surface protection are analyzed. Knowing the corrosion process mechanism reinforcement steel can be protected by different protection methods even in the presence of crevices larger than those anticipated by design. The selection of the corrosion protection method depends on the reduction level of the reinforcement steel corrosion which in its turn is determined by the atmospheric conditions. The selection of the accelerated co...

  6. Investigation of Corrosion and Cathodic Protection in Reinforced Concrete. II: Properties of Steel Surface Layers

    Koleva, D.A.; De Wit, J.H.W.; Van Breugel, K.; Lodhi, Z.F.; Ye, G.

    2007-01-01

    The present study explores the formation of corrosion products on the steel surface (using as-received low carbon construction steel) in reinforced concrete in conditions of corrosion and subsequent transformation of these layers in conditions of cathodic protection (CP).

  7. Characterisation of corrosion products on pipeline steel under cathodic protection

    Lanarde, Lise [Gaz de France Research and Development Division, 361 avenue du President Wilson, BP33, 93211 Saint Denis La Plaine (France)]|[UPR15 du CNRS, Laboratoire des Interfaces et Systemes Electrochimiques, Universite Pierre et Marie Curie, C.P. 133, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Campaignolle, Xavier; Karcher, Sebastien; Meyer, Michel [Gaz de France Research and Development Division, 361 avenue du President Wilson, BP33, 93211 Saint Denis La Plaine (France); Joiret, Suzanne [UPR15 du CNRS, Laboratoire des Interfaces et Systemes Electrochimiques, Universite Pierre et Marie Curie, C.P. 133, 4 Place Jussieu 75252 Paris Cedex 05 (France)

    2004-07-01

    Onshore gas transmission lines are conjointly protected against external corrosion by cathodic protection (CP) and organic coatings. If both protection systems are simultaneously faulty, the pipe may be subjected to local loss of protection criteria. Consequently, the development of a corrosion due to the ground intrinsic corrosiveness may occur. To guarantee an optimal and safe use of its 31000 km buried gas transmission network, Gaz de France regularly inspects its pipelines. When indications of metal damage are suspected, excavations are realized to carry out a finer diagnosis and, if necessary, to repair. Whenever, corrosions are encountered, although it occurs very scarcely, it is necessary to evaluate its degree of gravity: activity, mechanism, and kinetics. Among corrosion defects, it is indeed essential to differentiate those active, from those older inactive at the time of excavation, since those last ones may possibly have been annihilated, by a PC reinforcement for instance. Eventually, the identification of the corrosion mechanism and its associated rate will provide an assessment of the risks encountered by other sections of the pipeline similar to that excavated. This study investigates to what extent the degree of gravity (activity, kinetics) of a corrosion can be determined by the characterization and identification of its associated corrosion products. Moreover, it will attempt to relate it to the close environment features as well as to the operating conditions of the pipe. The preliminary results presented in this paper consist in a laboratory study of the time evolution of corrosion products formed on the surface of ordinary low carbon steel samples. The specimens have been previously subjected to various polarization conditions in various aqueous media. The selected solutions are characteristic of ground waters. The main parameters considered for the definition of the media were its initial chemical composition, pH and dissolved gas composition

  8. Spectroscopic identification of protective and non-protective corrosion coatings on steel structures in marine environments

    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. In conjunction with X-ray diffraction and micro-Raman analyses, the iron oxides that form the rusts on steels corroded in different marine and other environments can be completely identified and mapped within the rust coating. The spectroscopic analyses can be used to determine the nature of the environment in which structural steels have been, and these act as a monitor of the corrosion itself. Moessbauer spectroscopy is playing an important role in a new corrosion program in the United States and Japan 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 archaeological artifacts, and it is providing guidance to aid in the removal of the oxides necessary for their conservation

  9. Microbial iron respiration can protect steel from corrosion.

    Dubiel, M; Hsu, C H; Chien, C C; Mansfeld, F; Newman, D K

    2002-03-01

    Microbiologically influenced corrosion (MC) of steel has been attributed to the activity of biofilms that include anaerobic microorganisms such as iron-respiring bacteria, yet the mechanisms by which these organisms influence corrosion have been unclear. To study this process, we generated mutants of the iron-respiring bacterium Shewanella oneidensis strain MR-1 that were defective in biofilm formation and/or iron reduction. Electrochemical impedance spectroscopy was used to determine changes in the corrosion rate and corrosion potential as a function of time for these mutants in comparison to the wild type. Counter to prevailing theories of MC, our results indicate that biofilms comprising iron-respiring bacteria may reduce rather than accelerate the corrosion rate of steel. Corrosion inhibition appears to be due to reduction of ferric ions to ferrous ions and increased consumption of oxygen, both of which are direct consequences of microbial respiration. PMID:11872499

  10. Microbial Iron Respiration Can Protect Steel from Corrosion

    Dubiel, M.; Hsu, C H; Chien, C. C.; Mansfeld, F.; Newman, D. K.

    2002-01-01

    Microbiologically influenced corrosion (MC) of steel has been attributed to the activity of biofilms that include anaerobic microorganisms such as iron-respiring bacteria, yet the mechanisms by which these organisms influence corrosion have been unclear. To study this process, we generated mutants of the iron-respiring bacterium Shewanella oneidensis strain MR-1 that were defective in biofilm formation and/or iron reduction. Electrochemical impedance spectroscopy was used to determine changes...

  11. Synthesizing and Characterizing a Waterborne Polyaniline for Corrosion Protection of Steels

    Pan, Tongyan; Yu, Qifeng; Miao, Tao

    2015-02-01

    This study explores the idea of synthesizing and characterizing a new intrinsically conducting polyaniline that at the molecular level carries a hydrophilic component, making the polymer highly waterborne and thereby applicable to massive production for corrosion protection of steels. The waterborne polyaniline was mixed in a water-based epoxy and then coated on SAE 1008/1010 steel samples for evaluating its anti-corrosion capacity using a powerful surface-analysis tool, Scanning Kelvin Probe Force Microscopy (SKPFM). The high resolution surface topography and corrosion potential of steel samples coated with the Polyaniline-based primer, as studied by SKPFM, show significantly lower corrosion activities than two control groups: uncoated steel samples and epoxy-only coated samples that were also subjected to SKPFM analyses under the same corrosive condition. The surface analysis results indicate that this new waterborne polyaniline is capable of protecting steels from corrosion when mixed in conventional water-based epoxies, opening the door to the development of an economical and long-life coating for corrosion protection of steel structures.

  12. Mechanism of protective film formation during CO2 corrosion of X65 pipeline steel

    2008-01-01

    Electrochemical techniques,X-ray diffraction (XRD),and scanning electron microscopy (SEM) were applied to study the corrosion behaviors of X65 steel in static solution with carbon dioxide (CO2 at 65℃.The results show that iron carbonate (FeCO3deposits on the steel surface as a corrosion product scale.This iron carbonate scale acts as a barrier to CO2 corrosion,and can reduce the general corrosion rate.The protection ability of the scale is closely related to the scale morphological characteristics.

  13. Electrodeposition of zinc-doped silane films for corrosion protection of mild steels

    Highlights: ► Metallic zinc is doped into organosilane films by one-step electrodeposition. ► The composite films exhibit the improved corrosion resistance of mild steels. ► Zinc-doping provides additional cathodic protection to the mild steels. - Abstract: Organosilane/zinc composite films are prepared by one-step electrodeposition onto cold-rolled steels for corrosion protection. Electrochemical impedance spectroscopy measurement, bulk solution immersion and wet heat tests all show that the composite films have improved corrosion performance. X-ray photoelectron spectroscopy measurement suggests the successful encapsulation of metallic zinc. The embedding of metallic zinc results in negative shift in open-circuit potential of the film-covered electrodes. Such cathodic protection effect given by the metallic zinc provides the improved corrosion resistance of the composite films.

  14. Polypyrrole electrochemistry: Environmentally friendly corrosion protection of steel: (im)possibilities

    Hamer, W.J.

    2005-01-01

    Chromate compounds have been widely used to improve the corrosion protection of galvanised steel and aluminium objects in the past decades. The hexavalent chromium in chromate enhances the adherence of coatings to galvanised steel and aluminium. Additionally, if the passive layers on these material

  15. Application of Self Assembled 6-aminohexanol layers for corrosion protection of 304 stainless steel surface

    Yu Fei [Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100 (China); Chen Shougang, E-mail: sgchen2000@yahoo.com.cn [Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100 (China); Li Houmin; Yang Lejiao [Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100 (China); Yin Yansheng [Institute of Marine Materials Science and Engineering, Shanghai Maritime University, Shanghai 200135 (China)

    2012-05-31

    Grafting of 6-aminohexanol onto a 304 stainless steel substrate was performed with the assistance of polydopamine self assembly. The surface structure of the films was characterized using optical and scanning electron microscopy and X-ray energy dispersive spectroscopy confirmed the establishment of organic films. The corrosion resistance properties were characterized using the electrochemical impedance spectroscopy and potentiodynamic polarization curve measurements. Enhanced corrosion resistance performance was mainly ascribed to the compact film structure and the blocking characteristics against electron transfer of the modified 304 stainless steel substrate. - Highlights: Black-Right-Pointing-Pointer Organic layers for corrosion protection of 304 stainless steel (SS) surface. Black-Right-Pointing-Pointer Bio-inspired self assembly of polydopamine/composite films. Black-Right-Pointing-Pointer 6-aminohexanol membrane synthesized on polydopamine modified SS surface. Black-Right-Pointing-Pointer An efficiency route for improving corrosion protection.

  16. Application of Self Assembled 6-aminohexanol layers for corrosion protection of 304 stainless steel surface

    Grafting of 6-aminohexanol onto a 304 stainless steel substrate was performed with the assistance of polydopamine self assembly. The surface structure of the films was characterized using optical and scanning electron microscopy and X-ray energy dispersive spectroscopy confirmed the establishment of organic films. The corrosion resistance properties were characterized using the electrochemical impedance spectroscopy and potentiodynamic polarization curve measurements. Enhanced corrosion resistance performance was mainly ascribed to the compact film structure and the blocking characteristics against electron transfer of the modified 304 stainless steel substrate. - Highlights: ► Organic layers for corrosion protection of 304 stainless steel (SS) surface. ► Bio-inspired self assembly of polydopamine/composite films. ► 6-aminohexanol membrane synthesized on polydopamine modified SS surface. ► An efficiency route for improving corrosion protection.

  17. Corrosion Protection Service Life of Epoxy-Coated Reinforcing Steel in Virginia Bridge Decks

    Brown, Michael C.; Weyers, Richard E.; Megan C. Wheeler

    2003-01-01

    The corrosion protection service life extension provided by epoxy-coated reinforcement (ECR) was determined by comparing ECR and bare steel bars from 10 Virginia bridge decks built between 1981 and 1995. The objective was to determine the corrosion protection service life time extension provided by ECR field specimens with various degrees of coating adhesion: disbonded, partially disbonded, and wholly bonded coatings. The size and length distributions of cracks in Virginia bridge decks were i...

  18. Corrosion and cathodic protection of carbon steel in the tidal zone: Products, mechanisms and kinetics

    Highlights: • The corrosion product layer forming in the tidal zone is mainly made up of magnetite. • A thin film of magnetite is formed on the steel surface under cathodic protection. • Magnetite is formed during cathodic protection under the calcareous deposit. • Pre-existing corrosion product layers are almost not modified by cathodic protection. - Abstract: Carbon steel coupons were set in the tidal zone of a French seaport for 7 years with or without cathodic protection. The average corrosion rates decreased from 90 μm yr−1 to 9 μm yr−1 under cathodic protection. The corrosion product layers covering the unprotected coupons, characterized by Raman spectroscopy and X-ray diffraction, were mainly made up of magnetite and Fe(III) oxyhydroxides, with magnetite being clearly predominant. The products of the residual corrosion process under cathodic protection, similar to those observed at open circuit potential, formed a thin layer on the steel surface under the calcareous deposit

  19. Parameters Influencing the Corrosion Protection Service Life of Epoxy Coated Reinforcing Steel in Virginia Bridge Decks

    Wheeler, Megan Caroline

    2003-01-01

    This study is an evaluation of epoxy coated reinforcing steel (ECR) and its ability to effectively provide corrosion protection in reinforced concrete highway bridge decks. An analysis was conducted on 10 bridge decks built in the state of Virginia between the years 1981 and 1995. A total of 141 cores containing either ECR or bare steel were evaluated. A chloride solution was applied to the surface on a weekly cycle (for a total duration of 3.06 years) and a nondestructive electrochemica...

  20. Indium oxide thin film as potential photoanodes for corrosion protection of stainless steel under visible light

    Graphical abstract: If the conduction band potential of In2O3 is more negative than the corrosion potential of stainless steel, photo-induced electrons will be transferred from In2O3 to the steel, thus shifting the potential of the steel into a corrosion immunity region and preventing the steel from the corrosion. - Highlights: • Indium oxide performed novel application under visible light. • Indium oxide by sol–gel method behaved better photoelectrochemical properties. • Electrons were transferred to stainless steel from indium oxide once light on. - Abstract: This paper reports the photoelectrochemical cathodic protection of 304 stainless steel by In2O3 thin-film under visible-light. The films were fabricated with In2O3 powders, synthesized by both sol–gel (In2O3-sg) and solid-state (In2O3-ss) processes. The photo-induced open circuit potential and the photo-to-current efficiency measurements suggested that In2O3 could be a promising candidate material for photoelectrochemical cathodic protection of metallic alloys under visible light. Moreover, the polarization curve experimental results indicated that In2O3-sg thin-film can mitigate the corrosion potential of 304 stainless steel to much more negative values with a higher photocurrent density than the In2O3-ss film under visible-light illumination. All the results demonstrated that the In2O3-sg thin-film provides a better photoelectrochemical cathodic protection for 304 stainless steel than In2O3-ss thin-film under visible-light illumination. The higher photoelectrochemical efficiency is possibly due to the uniform thin films produced with the smaller particle size of In2O3-sg, which facilitates the transfer of the photo-induced electrons from bulk to the surface and suppresses the charge recombination of the electrons and holes

  1. A polyaniline based intrinsically conducting coating for corrosion protection of structural steels.

    Pan, Tongyan; Wang, Zhaoyang

    2013-11-01

    Among the various corrosion protection strategies for structural steels, coating techniques provide the most cost-effective protection and have been used as the primary mode of corrosion protection. Existing coating techniques however have been used mainly for their barrier capability and therefore all have a limited service life due to oxidation aging, electrolytic degradation, or various inadvertent defects and flaws occurred in and after coating applications. This work investigated the anti-corrosion potential of a π-conjugated polymer-polyaniline (PANi), which was doped into an intrinsically conducting polymer and then included in a two-layer coating system as a primer layer. To achieve a long service life, the primer layer was made by mixing the conductive PANi in a waterborne poly-vinyl butyral solution to provide strong adhesion to steel surface, and then topcoated with a layer of elastomer-modified polyethylene to obtain extra mechanical and barrier protections. Two ASTM standard tests were conducted to evaluate the corrosion durability and tensile adhesion of the two-layer system, in which the system demonstrated superior performance. The Scanning Kelvin Probe Force Microscopy (SKPFM) was used to provide the microscopic evidences for the outstanding performance. PMID:24000080

  2. Corrosion protection

    This invention describes a corrosion protection device for long-term storage containers of radioactive matter, in particular of irradiated fuel elements stored in geological formations apt for the purpose. This device prevents corrosion of the containers even if water emerges unexpectedly, or, in any case, inhibits and minimizes corrosion. The device comprehends reactive anodes that are connected to the containers by means of conductive connections. (orig.)

  3. Stoichiometric titanium dioxide ion implantation in AISI 304 stainless steel for corrosion protection

    Hartwig, A.; Decker, M.; Klein, O.; Karl, H.

    2015-12-01

    The aim of this study is to evaluate the applicability of highly chemically inert titanium dioxide synthesized by ion beam implantation for corrosion protection of AISI 304 stainless steel in sodium chloride solution. More specifically, the prevention of galvanic corrosion between carbon-fiber reinforced plastic (CFRP) and AISI 304 was investigated. Corrosion performance of TiO2 implanted AISI 304 - examined for different implantation and annealing parameters - is strongly influenced by implantation fluence. Experimental results show that a fluence of 5 × 1016 cm-2 (Ti+) and 1 × 1017 cm-2 (O+) is sufficient to prevent pitting corrosion significantly, while galvanic corrosion with CFRP can already be noticeably reduced by an implantation fluence of 5 × 1015 cm-2 (Ti+) and 1 × 1016 cm-2 (O+). Surface roughness, implantation energy and annealing at 200 °C and 400 °C show only little influence on the corrosion behavior. TEM analysis indicates the existence of stoichiometric TiO2 inside the steel matrix for medium fluences and the formation of a separated metal oxide layer for high fluences.

  4. Comparative Study on Corrosion Protection of Reinforcing Steel by Using Amino Alcohol and Lithium Nitrite Inhibitors

    Han-Seung Lee

    2015-01-01

    Full Text Available In this study, the ability of lithium nitrite and amino alcohol inhibitors to provide corrosion protection to reinforcing steel was investigated. Two types of specimens—reinforcing steel and a reinforced concrete prism that were exposed to chloride ion levels resembling the chloride attack environment—were prepared. An autoclave accelerated corrosion test was then conducted. The variables tested included the chloride-ion concentration and molar ratios of anti-corrosion ingredients in a CaOH2-saturated aqueous solution that simulated a cement-pore solution. A concentration of 25% was used for the lithium nitrite inhibitor LiNO2, and an 80% solution of dimethyl ethanolamine ((CH32NCH2CH2OH, hereinafter DMEA was used for the amino alcohol inhibitor. The test results indicated that the lithium nitrite inhibitor displayed anti-corrosion properties at a molar ratio of inhibitor of ≥0.6; the amino alcohol inhibitor also displayed anti-corrosion properties at molar ratios of inhibitor greater than approximately 0.3.

  5. Corrosion Protection of Carbon Steel Using Poly aniline Composite with Inorganic Pigments

    Two inorganic pigments (TiO2 and SiO2) were used to prepare composites with poly aniline (PANI) by situ polymerization method. PANI and PANI composites with SiO2 and TiO2 were characterized using Fourier transform infrared spectroscopy and X-ray diffraction. The morphology of the synthesized pigments (PANI , PANI-SiO2 and PANI-TiO2) was examined using scanning electron microscopy. Samples were then used as pigments through blending them with acrylic paint and applied on the surface of carbon steel panels. Corrosion was evaluated for coating of carbon steel panels through full immersion test up to standard ASTMG 31. Mass loss was calculated after they have been exposed in acidic media. A digital camera was also used for monitoring corrosion visually on the surface of carbon steel specimens. The results revealed that acrylic paint pigmented by PANI-SiO2 composite was more efficient in corrosion protection for carbon steel compared with the other synthesized pigments. (author)

  6. Characterization of organic-inorganic hybrid coatings for corrosion protection of galvanized steel and electroplated ZnFe steel

    Maria Eliziane Pires de Souza

    2006-03-01

    Full Text Available The development of hybrids materials has been extensively investigated in recent years. The combination of a wide variety of compositions and production processes had permitted the use of these materials in different applications like coatings for corrosion protection of metals. In this work organic-inorganic hybrid materials have been prepared from the hydrolysis of tetraethylorthosilicate and silanol-terminated polidymetilmetoxysilane using a sol-gel process. These materials have been applied on galvanized steel and on steel electroplated with a ZnFe. In order to evaluate the degradation behavior of these coatings, electrochemical techniques (Electrochemical Impedance Spectroscopy and Potentiodynamic Polarization were used. EIS data was fitted to an equivalent circuit from which the electrochemical parameters were obtained. Results show a good protective character of the hybrid films, when compared with uncovered specimens. The overall performance of the coating systems appears to be highly dependent on the kind of metallic coating applied to the steel.

  7. Oxidation of steels in liquid lead bismuth: Oxygen control to achieve efficient corrosion protection

    Martinelli, Laure, E-mail: laure.martinelli@cea.f [CEA, DEN, DPC, SCCME, Laboratoire d' Etude de la Corrosion Non Aqueuse, F-91191 Gif-sur-Yvette (France); Jean-Louis, Courouau; Fanny, Balbaud-Celerier [CEA, DEN, DPC, SCCME, Laboratoire d' Etude de la Corrosion Non Aqueuse, F-91191 Gif-sur-Yvette (France)

    2011-05-15

    Hybrid systems dedicated to waste transmutation are constituted of an accelerator generating a high energy proton flux, a spallation target on which the accelerated proton beam impinges to produce neutrons and a subcritical core. The Pb-Bi eutectic liquid alloy is considered as spallation target material due to its suitable nuclear and physical properties. However, liquid metals can be corrosive towards containment materials (austenitic and Fe9Cr alloys). In the case of liquid lead bismuth alloy, one of the protection means considered against the dissolution of the steels is the in situ protection by the formation of an oxide layer at the steels' surface. However, in order to ensure the efficient protection of the steels by an oxide layer, the control and the monitoring of the oxygen content in the Pb-Bi alloy is a major issue. The paper recalls, first, the oxygen chemistry in a lead alloy system, in order to propose the oxygen operating window that complies with both the contamination by lead oxide of the coolant and the corrosion control by the promotion of an oxide film on the structure. Results of tests performed in stagnant lead bismuth at high oxygen concentrations are also presented showing the effect of various operating parameters on the oxidation kinetics and on the nature of the oxide layer. An oxidation mechanism and model are also proposed and compared with experimental data.

  8. Self-immunity microcapsules for corrosion protection of steel bar in reinforced concrete

    Wang, Yanshuai; Fang, Guohao; Ding, Weijian; Han, Ningxu; Xing, Feng; Dong, Biqin

    2015-12-01

    A novel microcapsule-based self-immunity system for reinforced concrete is proposed. Its feasibility for hindering the corrosion of steel rebar by means of lifting the threshold value of [Cl-]/[OH-] is discussed. Precisely controlled release behavior enables corrosion protection in the case of depassivation. The release process is characterized over a designated range of pH values, and its release characteristics of the microcapsules, triggered by decreasing pH value, are captured by observing that the core crystals are released when exposed to a signal (stimulus). The aim of corrosion protection of steel bar is achieved through the constantly-stabilized passive film, and its stability is promoted using continuous calcium hydroxide released from the microcapsule, restoring alkaline conditions. The test results exhibited that the release process of the microcapsules is a function of time. Moreover, the release rate of core materials could interact with environmental pH value, in which the release rate is found to increase remarkably with decreasing pH value, but is inhibited by high pH levels.

  9. Selection of varnish-and-paint system for protection of 20Kh3MVF steel from atmospheric corrosion

    A varish-and-paint system has been selected for protecting steel 20Kh3MVF against atmospheric corrosion under conditions of elevated temperatures and humidity. It has been established that optimum protection of steel can be achieved by coating it with epoxy enamel EhP-525 in combination with surface phosphating. For lono.-term protection, enamel ML-12 coatings on the phosphate layer are recommended

  10. Corrosion protection of low-carbon steel using exopolysaccharide coatings from Leuconostoc mesenteroides

    Corrosion is one of the most serious and challenging problems faced worldwide by industry. This research investigates the inhibition of corrosive behavior of SAE1010 steel by bacterial exopolysaccharides. Electrochemical Impedance Spectroscopy was used to evaluate the corrosion inhibition of diffe...

  11. Corrosion protection performance of porous strontium hydroxyapatite coating on polypyrrole coated 316L stainless steel.

    Gopi, D; Ramya, S; Rajeswari, D; Kavitha, L

    2013-07-01

    Polypyrrole/strontium hydroxyapatite bilayer coatings were achieved on 316L stainless steel (316L SS) by the electropolymerisation of pyrrole from sodium salicylate solution followed by the electrodeposition of porous strontium hydroxyapatite. The formation and the morphology of the bilayer coatings were characterised by Fourier transform infrared spectroscopy (FT-IR) and high resolution scanning electron microscopy (HRSEM), respectively. The corrosion resistance of the coated 316L SS specimens was investigated in Ringer's solution by electrochemical techniques and the results were substantiated with inductively coupled plasma atomic emission spectrometry (ICP-AES). The passive film underneath the polypyrrole layer is effective in protecting 316L SS against corrosion in Ringer's solution. Moreover, we believe that the top porous strontium hydroxyapatite layer can provide potential bioactivity to the 316L SS. PMID:23475060

  12. Use of Extracted Green Inhibitors as a Friendly Choice in Corrosion Protection of Low Alloy Carbon Steel

    Jano, A.

    2012-11-01

    Full Text Available Mitigation of corrosion impact on environment is an important step in environmental protection. Use of environmentally friendly corrosion protection methods is very important. It is smart to choose cheap and safe to handle compounds as corrosion inhibitors. The use of green inhibitors (extracted inexpensively, from the seed endosperm of some Leguminosae plants, and investigation of their efficiency in corrosion protection is the aim of this study. As green inhibitor one kind of polysaccharides (galactomannan from locust bean gum (also known as carob gum, carob bean gum extracted from the seed of carob tree is used. Corrosion protection efficiency of these extracted green inhibitors was tested for carbon steel marked as: steel 39, steel 44, and iron B 500 (usually applied as reinforcing bars to concrete. Sulfuric acid solution in the presence of chloride ions was used as corrosion media. The composition of corrosion acid media used was 1 mol L-1 H2SO4 and 10-3 mol L-1 Cl- (in the form of NaCl. Electrochemical techniques such as potentiodynamic polarization methods were used for inhibitor efficiency testing.

  13. Microbial corrosion of stainless steel.

    Ibars, J R; Moreno, D A; Ranninger, C

    1992-11-01

    Stainless steel, developed because of their greater resistance to corrosion in different aggressive environments, have proved to be affected, however, by various processes and types of corrosion. Some of these types of corrosion, mainly pitting, is activated and developed in the presence of microorganisms, which acting in an isolated or symbiotic way, according to their adaptation to the environment, create a favorable situation for the corrosion of these steel. The microorganisms that are involved, mainly bacteria of both the aerobic and anaerobic type, modify the environment where the stainless steel is found, creating crevices, differential aeration zones or a more aggressive environment with the presence of metabolites. In these circumstances, a local break of the passive and passivating layer is produced, which is proper to these types of steel and impedes the repassivation that is more favorable to corrosion. In the study and research of these types of microbiologically influenced corrosion are found electrochemical techniques, since corrosion is fundamentally an electrochemical process, and microbiological techniques for the identification, culture, and evaluation of the microorganisms involved in the process, as well as in the laboratory or field study of microorganism-metal pairs. Microstructural characterization studies of stainless steel have also been considered important, since it is known that the microstructure of steel can substantially modify their behavior when faced with corrosion. As for surface analysis studies, it is known that corrosion is a process that is generated on and progresses from the surface. The ways of dealing with microbiologically influenced corrosion must necessarily include biocides, which are not always usable or successful, the design of industrial equipment or components that do not favor the adherence of microorganisms, using microstructures in steel less sensitive to corrosion, or protecting the materials. PMID:1492953

  14. On the protective effect of KhOSP-10 inhibitor during corrosion, hydrogenadsorption and corrosion cracking of a steel in sulfuric acid

    The protective propeties of inhibitor KhOSP-10 in the time of corrosion and corrosive cracking of steel 40Kh are higher then those of inhibitors KPI-1, KI-1, I-I-V etc. Its ability to reduce steel hydrogenation is the same as in the case of KPI-1 inhibitor i.e. below that of KI-1. HCl additives enhance the efficiency of inhibitors KPI-1, KI-1, I-1-V etc. up to the protective ability of KhOSP-10. Kinetics of the electrode processes was estimated from polarization curves

  15. Corrosion properties of steel protected by nanometre-thick oxide coatings

    Highlights: • 40–50 nm mixed alumina–tantala coatings were grown by atomic layer deposition. • Effects of substrate surface finish and oxide mix were analysed. • Nanolaminate stacks are better resistant to breakdown. • Localised corrosion occurs at pre-existing coating defects exposing substrate sites. • Substrate brushing and H2–Ar plasma pre-treatment hinder pit initiation. - Abstract: A comprehensive study of the corrosion properties of low alloy steel protected by 40–50 nm aluminium and tantalum mixed oxide coatings grown by atomic layer deposition is reported. Electrochemical and surface analysis was performed to address the effect of substrate surface finish and whether an oxide mixture or nanolaminate was used. There was no dissolution or breakdown for nanolaminate alumina/tantala stacks in acidic NaCl solution. Localised corrosion (pitting) took place when defects exposing the substrate pre-existed in the coating. Substrate pre-treatment by brushing and H2–Ar plasma was instrumental to block or slow down pit initiation by reducing the defect dimensions

  16. Corrosion Protection of Steel by Thin Coatings of Starch-oil Emulsions

    Corrosion of materials is one of the most serious and challenging problems faced worldwide by industry. This research investigated the inhibition of corrosive behavior by jet-cooked starch-soybean oil composites on SAE 1010 steel. Electrochemical Impedance Spectroscopy (EIS) was used to evaluate t...

  17. The effect of oil on carbon dioxide corrosion inhibition on carbon steel - potential for improved corrosion protection

    Foss, Martin Smedstad

    2009-07-01

    The search for robust and cost efficient ways to prevent internal corrosion of carbon steel piping and equipment in oil and gas production and transportation has lead to the development of highly sophisticated CO{sub 2} corrosion inhibitor products. This thesis studies oil wetting and corrosion inhibitor performance on bare steel and steel with corrosion product deposits on the surface, in the presence of a refined, low aromatic hydrocarbon oil. Three surfactants were used in the experiments; two commercial inhibitor base chemicals; an oleic imidazoline salt (OI) and a phosphate ester (PE), and cetyl trimethyl ammonium bromide (CTAB), a well characterized quaternary ammonium compound. Adsorption characteristics of the inhibitors on corroding iron and FeCO{sub 3} particles were also studied. Polarization resistance (PR) and electrochemical impedance spectroscopy (EIS) techniques were used to study the effect of the oil on the performance of the inhibitors. The performance testing was done on corroding carbon steel without any surface deposits and on carbon steel with either ferrous carbonate (FeCO{sub 3}) or ferric corrosion products on the surface. The results showed that the addition of oil in the inhibitor tests had a significant, positive effect on the performance of the two commercial corrosion inhibitors; decrease in corrosion rate of about one order of magnitude compared to the rate without oil was found. Based on the EIS data it was concluded that the improved performance was caused by a modification of the inhibitor film and not the formation of a macroscopic oil film on the steel surface. Indications of oil wetting of the steel surface were only found when ferric corrosion products were present and OI was used as the inhibitor. No such effects were seen on bare steel or on FeCO{sub 3} covered surfaces. Contact angle measurements and dispersion tests were used to investigate the effect of the inhibitors on the wettability of the three types of surfaces when

  18. The effect of oil on carbon dioxide corrosion inhibition on carbon steel - potential for improved corrosion protection

    The search for robust and cost efficient ways to prevent internal corrosion of carbon steel piping and equipment in oil and gas production and transportation has lead to the development of highly sophisticated CO2 corrosion inhibitor products. This thesis studies oil wetting and corrosion inhibitor performance on bare steel and steel with corrosion product deposits on the surface, in the presence of a refined, low aromatic hydrocarbon oil. Three surfactants were used in the experiments; two commercial inhibitor base chemicals; an oleic imidazoline salt (OI) and a phosphate ester (PE), and cetyl trimethyl ammonium bromide (CTAB), a well characterized quaternary ammonium compound. Adsorption characteristics of the inhibitors on corroding iron and FeCO3 particles were also studied. Polarization resistance (PR) and electrochemical impedance spectroscopy (EIS) techniques were used to study the effect of the oil on the performance of the inhibitors. The performance testing was done on corroding carbon steel without any surface deposits and on carbon steel with either ferrous carbonate (FeCO3) or ferric corrosion products on the surface. The results showed that the addition of oil in the inhibitor tests had a significant, positive effect on the performance of the two commercial corrosion inhibitors; decrease in corrosion rate of about one order of magnitude compared to the rate without oil was found. Based on the EIS data it was concluded that the improved performance was caused by a modification of the inhibitor film and not the formation of a macroscopic oil film on the steel surface. Indications of oil wetting of the steel surface were only found when ferric corrosion products were present and OI was used as the inhibitor. No such effects were seen on bare steel or on FeCO3 covered surfaces. Contact angle measurements and dispersion tests were used to investigate the effect of the inhibitors on the wettability of the three types of surfaces when they were exposed to

  19. Parameters Governing the Corrosion Protection Efficiency of Fusion-Bonded Epoxy Coatings on Reinforcing Steel

    Andrei Ramniceanu; Weyers, Richard E.; Brown, Michael C.; Sprinkel, Michael M.

    2008-01-01

    The purpose of this study was to investigate various epoxy coating and exposure parameters to determine their effects on the corrosion of reinforcing steel. The parameters investigated were: chloride content at the bar depth, coated bar corroded area, corrosion product color under the coating, epoxy coating adhesion, coating color, coating damage (holidays and holes), coating thickness, TGA, DSC and EDS analysis and SEM coating cracking investigation. This study demonstrated that the ECR coat...

  20. Chromate-free Hybrid Coating for Corrosion Protection of Electrogalvanized Steel Sheets

    Jo, Duhwan; Kwon, Moonjae; Kim, Jongsang [POSCO Technical Research Laboratories, Pohang (Korea, Republic of)

    2012-01-15

    Both electrogalvanized and hot-dip galvanized steel sheets have been finally produced via organic-inorganic surface coating process on the zinc surface to enhance corrosion resistance and afford additional functional properties. Recently, POSCO has been developed a variety of chromate-free coated steels that are widely used in household, construction and automotive applications. New organic-inorganic hybrid coating solutions as chromate alternatives are comprised of surface modified silicate with silane coupling agent and inorganic corrosion inhibitors as an aqueous formulation. In this paper we have prepared new type of hybrid coatings and evaluated quality performances such as corrosion resistance, spot weldability, thermal tolerance, and paint adhesion property etc. The electrogalvanized steels with these coating solutions exhibit good anti-corrosion property compared to those of chromate coated steels. Detailed components composition of coating solutions and experimental results suggest that strong binding between organic-inorganic hybrid coating layer and zinc surface plays a key role in the advanced quality performances.

  1. An electrochemical study of corrosion protection by primer-topcoat systems on 4130 steel with ac impedance and dc methods

    Mendrek, M. J.; Higgins, R. H.; Danford, M. D.

    1988-01-01

    To investigate metal surface corrosion and the breakdown of metal protective coatings, the ac impedance method is applied to six systems of primer coated and primer topcoated 4130 steel. Two primers were used: a zinc-rich epoxy primer and a red lead oxide epoxy primer. The epoxy-polyamine topcoat was used in four of the systems. The EG and G-PARC Model 368 ac impedance measurement system, along with dc measurements with the same system using the polarization resistance method, were used to monitor changing properties of coated 4230 steel disks immersed in 3.5 percent NaCl solutions buffered at pH 5.4 over periods of 40 to 60 days. The corrosion system can be represented by an electronic analog called an equivalent circuit consisting of resistors and capacitors in specific arrangements. This equivalent circuit parallels the impedance behavior of the corrosion system during a frequency scan. Values for the resistors and capacitors, that can be assigned in the equivalent circuit following a least-squares analysis of the data, describe changes that occur on the corroding metal surface and in the protective coatings. Two equivalent circuits have been determined that predict the correct Bode phase and magnitude of the experimental sample at different immersion times. The dc corrosion current density data are related to equivalent circuit element parameters. Methods for determining corrosion rate with ac impedance parameters are verified by the dc method.

  2. Multilayer Al2O3/TiO2 Atomic Layer Deposition coatings for the corrosion protection of stainless steel

    Atomic Layer Deposition (ALD) is used to deposit conformal nanometric layers onto different substrates. In this paper, characterization of different ALD layers has been carried out in order to evaluate the suitability of this deposition technolnique for the corrosion protection of stainless steel substrates. Al2O3, TiO2 and multilayer configurations, have been deposited on AISI 316 austenitic stainless steel and have then been investigated using atomic force microscopy (AFM), glow discharge optical emission spectrometry (GDOES), scanning electron microscopy (SEM), Vickers indentation and potentiodynamic polarizations (PP). AFM has been used to obtain a morphological characterization and to evaluate the thickness of the depositions. SEM has been used to investigate the presence of deposition defects. GDOES has been used to obtain a compositional profile. Vickers indentations were used in order to evaluate the resistance to delamination. PPs have been used in order to evaluate the corrosion protection. The results have showed that corrosion resistance can be effectively enhanced. Multilayer configuration proved to be more effective than single layers configurations. - Highlights: ► Atomic Layer Deposition (ALD) coatings with different thicknesses were tested. ► Glow Discharge Optical Emission Spectroscopy gave in-depth composition profiles. ► Corrosion resistance was strongly enhanced by ALD. ► Coating to substrate adhesion was improved for thin and multilayer coatings. ► Multilayer ALD configurations proved to be more protective than single layers.

  3. Oleic acid-grafted chitosan/graphene oxide composite coating for corrosion protection of carbon steel.

    Fayyad, Eman M; Sadasivuni, Kishor Kumar; Ponnamma, Deepalekshmi; Al-Maadeed, Mariam Al Ali

    2016-10-20

    An anticorrosion coating film based on the formation of nanocomposite coating is reported in this study. The composite consisted of chitosan (green matrix), oleic acid, and graphene oxide (nano filler). The nanocomposite coating was arranged on the surface of carbon steel, and the corrosion resistance was monitored using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP). Compared to the pure chitosan (CS) coating, the corrosion resistance of oleic acid-modified chitosan/graphene oxide film (CS/GO-OA) is increased by 100 folds. Since the well-dispersed smart grafted nanolayers delayed the penetration rate of corrosive species and thus maintained long term anticorrosive stability which is correlated with hydrophobicity and permeability. PMID:27474635

  4. Corrosion protection of the reinforcing steels in chloride-laden concrete environment through epoxy/polyaniline–camphorsulfonate nanocomposite coating

    Highlights: • Epoxy/polyaniline–camphorsulfonate nanocomposite coating well protects steel rebar. • Coating performance is evaluated by impedance measurements up to 1 year. • Ultimate bond strength between the coated rebars and concrete is measured. • Self-compacting concrete shows better anticorrosive property compared to normal one. - Abstract: In this study, an epoxy/polyaniline–camphorsulfonate nanocomposite (epoxy/PANI–CSA) is employed to protect reinforcing steels in chloride-laden concrete environment. The synthesized nanocomposite was characterized using Fourier transform infrared spectroscopy and transmission electron microscopy. Bare, epoxy-coated and epoxy/PANI–CSA nanocomposite-coated steel rebars were embedded in normal and self-compacting concretes. To evaluate their corrosion behaviors, open circuit potential and impedance measurements were performed for the duration of 1 year. Ultimate bond strength of concrete with the reinforcement bars were measured in corroded and uncorroded conditions. It was found that epoxy/PANI–CSA coating provides good corrosion resistance and durable bond strength with concrete for steel rebars

  5. Fabrication of continuous mesoporous organic-inorganic nanocomposite films for corrosion protection of stainless steel in PEM fuel cells

    Graphical abstract: Ordered mesoporous organic-inorganic composite film has been achieved by sol-gel and spin-coating techniques. We believe that the mesoporous composite films have a potential application as a protect coating of bipolar plate material. Display Omitted Research highlights: → Ordered mesoporous composite film was deposited on the 304 stainless steel. → This composite film exhibited excellent protective performance in 0.5 M H2SO4. → The film exhibited a high surface tension with water contact angle close to 90o. - Abstract: The organic-inorganic composite film was deposited on the 304 stainless steel as bipolar plate material for proton exchange membrane fuel cells by spin-coating method. As shown by XRD, N2 adsorption-desorption and TEM, the composite films exhibit ordered mesoporous structures. The corrosion tests in 0.5 M H2SO4 system displayed that, compared with 304SS, the composite films made corrosion potential shifted to positive direction by 250-1000 mV (SCE) and corrosion current decreased by 1-3 orders of magnitude. Wherein, the C-50-60% composite film showed the optimal protective performance, its corresponding potentiostatic polarization process was extremely stable in the simulated fuel cells environment.

  6. Preparation of Crosslinked Amphiphilic Silver Nanogel as Thin Film Corrosion Protective Layer for Steel

    Ayman M. Atta

    2014-07-01

    Full Text Available Monodisperse silver nanoparticles were synthesized by a new developed method via reaction of AgNO3 and oleic acid with the addition of a trace amount of Fe3+ ions. Emulsion polymerization at room temperature was employed to prepare a core-shell silver nanoparticle with controllable particle size. N,N'-methylenebisacrylamide (MBA and potassium peroxydisulfate (KPS were used as a crosslinker, and as redox initiator system, respectively for crosslinking polymerization. The structure and morphology of the silver nanogels were characterized by Fourier transform infrared spectroscopy (FTIR, transmission and scanning electron microscopy (TEM and SEM. The effectiveness of the synthesized compounds as corrosion inhibitors for steel in 1 M HCl was investigated by various electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS. Monolayers of silver nanoparticle were self-assembled on the fresh active surface of the steel electrode and have been tested as a corrosion inhibitor for steel in 1 M HCl solution. The results of polarization measurements showed that nanogel particles act as a mixed type inhibitor.

  7. Multilayer graphene for long-term corrosion protection of stainless steel bipolar plates for polymer electrolyte membrane fuel cell

    Stoot, Adam C.; Camilli, Luca; Spiegelhauer, Susie-Ann; Yu, Feng; Bøggild, Peter

    2015-10-01

    Motivated by similar investigations recently published (Pu et al., 2015), we report a comparative corrosion study of three sets of samples relevant as bipolar plates for polymer electrolyte fuel cells: stainless steel, stainless steel with a nickel seed layer (Ni/SS) and stainless steel with Ni seed layer coated by a multi-layered graphene thin film (G/Ni/SS). The graphene film, synthesized by chemical vapour deposition (CVD), has a moderate amount of defects according to Raman spectroscopy. Short/medium-term corrosion test shows no significant advantage of using G/Ni/SS rather than Ni/SS, both samples exhibiting a similar trend, thus questioning the short-term positive effect of graphene coatings. However, partial immersion in boiling seawater for three weeks reveals a clear superiority of the graphene coating with respect to steel just protected by Ni. After the test, the graphene film is still intact with unchanged defect density. Our results show that even non-perfect multilayer graphene films can considerably increase the lifetime of future-generation bipolar plates for fuel cells.

  8. Investigation on the Effect of Green Inhibitors for Corrosion Protection of Mild Steel in 1 M NaOH Solution

    Premjith Jayakumar Ramakrishnan; Vishnu Deth Kaleekal Janardhanan; Ramkumar Sreekumar; Keerthy Parayil Mohan

    2014-01-01

    Alkaline corrosion is one of the main issues faced by the industries. The main chemicals abundantly used in industries are NaOH, H3PO4, HCl, and H2SO4. Corrosion control of metals has technical, economical, environmental, and aesthetical importance. The use of inhibitors is one of the best options to protect metals and alloys against corrosion. The corrosion protection of mild steel in 1 M NaOH solution by mix of Henna/Zeolite powder was studied at different temperatures by weight loss techni...

  9. Rare earth and silane as chromate replacers for corrosion protection on galvanized steel

    PENG Tianlan; MAN Ruilin

    2009-01-01

    The present work aimed at using rare earth lanthanum salt and trimethoxy(viny)silance as chromate substitutes for galvanized steel passivation, in contrast to zinc coating samples treated with chromate. The corrosion resistance was assessed by electrochemical impedance spectroscopy (EIS) and neutral salt spray tests (NSS). Scanning electron microscopy (SEM) was used to characterize the sample surfaces. The organic coating adhesion on the panel was also investigated via varnishes-cross cut tests. The results indicated that rare earth and silane two-step treatment gave more effective anticorrosion performance than Cr, which also provided good paint adhesion. The coating formation mechanism was also discussed.

  10. Study on cerium-doped nano-TiO2 coatings for corrosion protection of 316 L stainless steel

    Li, Suning; Wang, Qian; Chen, Tao; Zhou, Zhihua; Wang, Ying; Fu, Jiajun

    2012-04-01

    Many methods have been reported on improving the photogenerated cathodic protection of nano-TiO2 coatings for metals. In this work, nano-TiO2 coatings doped with cerium nitrate have been developed by sol-gel method for corrosion protection of 316 L stainless steel. Surface morphology, structure, and properties of the prepared coatings were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. The corrosion protection performance of the prepared coatings was evaluated in 3 wt% NaCl solution by using electrochemical techniques in the presence and absence of simulated sunlight illumination. The results indicated that the 1.2% Ce-TiO2 coating with three layers exhibited an excellent photogenerated cathodic protection under illumination attributed to the higher separation efficiency of electron-hole pairs and higher photoelectric conversion efficiency. The results also showed that after doping with an appropriate concentration of cerium nitrate, the anti-corrosion performance of the TiO2 coating was improved even without irradiation due to the self-healing property of cerium ions.

  11. Nanocomposite films for corrosion protection

    Sababi, Majid

    2013-01-01

    This thesis describes technical and scientific aspects of new types of composite films/coatings for corrosion protection of carbon steel, composite films with nanometer thickness consisting of mussel adhesive protein (Mefp‐1) and ceria nanoparticles, and polymeric composite coatings with micrometre thickness consisting of conducting polymer and ceria nanoparticles in a UV‐curing polyester acrylate (PEA) resin. The influence of microstructure on corrosion behaviour was studied for a Fe‐Cr‐V‐N ...

  12. Corrosion Protection of Electro-Galvanized Steel by Ceria-Based Coatings: Effect of Polyethylene Glycol (PEG) Addition

    Hamlaoui, Y.; Tifouti, L.; Pedraza, F.

    2013-09-01

    A cerium oxide thin layer was deposited onto galvanized steel by cathodic electrodeposition from 0.1 M concentrated cerium nitrate solution. In this work, the influence of polyethylene glycol (PEG) addition on the composition and morphology of the deposits is examined. The results showed that the addition of PEG to the cerium nitrate solutions leads to a decrease in the cracks in the deposits by decreasing the hydrogen reduction reaction and by decreasing the film thickness which provided enhanced corrosion protection. Moreover, the substrate dissolution reaction is inhibited.

  13. Investigation of thermal spray coatings on austenitic stainless steel substrate to enhance corrosion protection

    Rogers, Daniel M.

    The research is aimed to evaluate thermal spray coatings to address material issues in supercritical and ultra-supercritical Rankine cycles. The primary purpose of the research is to test, evaluate, and eventually implement a coating to improve corrosion resistance and increase efficiency of coal fired power plants. The research is performed as part of a comprehensive project to evaluate the ability of titanium, titanium carbide, or titanium diboride powders to provide fireside corrosion resistance in supercritical and ultra-supercritical steam boilers, specifically, coal driven boilers in Illinois that must utilize high sulfur and high chlorine content coal. [1] The powder coatings that were tested are nano-sized titanium carbide (TiC) and titanium di-boride (TiB2) powders that were synthesized by a patented process at Southern Illinois University. The powders were then sent to Gas Technology Institute in Chicago to coat steel coupons by HVOF (High Velocity Oxy-Fuel) thermal spray technique. The powders were coated on an austenitic 304H stainless steel substrate which is commonly found in high temperature boilers, pipelines, and heat exchangers. The samples then went through various tests for various lengths of time under subcritical, supercritical, and ultra-supercritical conditions. The samples were examined using a scanning electron microscope and x-ray diffraction techniques to study microstructural changes and then determined which coating performed best.

  14. Galvanic Liquid Applied Coating System For Protection of Embedded Steel Surfaces from Corrosion

    Curran, Joseph; Curran, Jerome; Voska, N. (Technical Monitor)

    2002-01-01

    Corrosion of reinforcing steel in concrete is an insidious problem facing Kennedy Space Center (KSC), other Government Agencies, and the general public. These problems include KSC launch support structures, highway bridge infrastructure, and building structures such as condominium balconies. Due to these problems, the development of a Galvanic Liquid Applied Coating System would be a breakthrough technology having great commercial value for the following industries: Transportation, Infrastructure, Marine Infrastructure, Civil Engineering, and the Construction Industry. This sacrificial coating system consists of a paint matrix that may include metallic components, conducting agents, and moisture attractors. Similar systems have been used in the past with varying degrees of success. These systems have no proven history of effectiveness over the long term. In addition, these types of systems have had limited success overcoming the initial resistance between the concrete/coating interface. The coating developed at KSC incorporates methods proven to overcome the barriers that previous systems could not achieve. Successful development and continued optimization of this breakthrough system would produce great interest in NASA/KSC for corrosion engineering technology and problem solutions. Commercial patents on this technology would enhance KSC's ability to attract industry partners for similar corrosion control applications.

  15. Atmospheric corrosion of mild steel

    Morcillo, M.; de la Fuente, D.; I. Díaz; Cano, H.

    2011-01-01

    The atmospheric corrosion of mild steel is an extensive topic that has been studied by many authors in different regions throughout the world. This compilation paper incorporates relevant publications on the subject, in particular about the nature of atmospheric corrosion products, mechanisms of atmospheric corrosion and kinetics of the atmospheric corrosion process, paying special attention to two matters upon which relatively less information has been published: a) the morphology of steel c...

  16. Use of Extracted Green Inhibitors as a Friendly Choice in Corrosion Protection of Low Alloy Carbon Steel

    Jano, A.; Lame (Galo), A.; Kokalari (Teli), E.

    2012-01-01

    Mitigation of corrosion impact on environment is an important step in environmental protection. Use of environmentally friendly corrosion protection methods is very important. It is smart to choose cheap and safe to handle compounds as corrosion inhibitors. The use of green inhibitors (extracted inexpensively, from the seed endosperm of some Leguminosae plants), and investigation of their efficiency in corrosion protection is the aim of this study. As green inhibitor one kind of polys...

  17. Effect of zinc phosphate chemical conversion coating on corrosion behaviour of mild steel in alkaline medium: protection of rebars in reinforced concrete

    Florica Simescu and Hassane Idrissi

    2008-01-01

    Full Text Available We outline the ability of zinc phosphate coatings, obtained by chemical conversion, to protect mild steel rebars against localized corrosion, generated by chloride ions in alkaline media. The corrosion resistance of coated steel, in comparison with uncoated rebars and coated and uncoated steel rebars embedded in mortar, were evaluated by open-circuit potential, potentiodynamic polarization, cronoamperometry and electrochemical impedance spectroscopy. The coated surfaces were characterized by x-ray diffraction and scanning electron microscopy. First, coated mild steel rebars were studied in an alkaline solution with and without chloride simulating a concrete pore solution. The results showed that the slow dissolution of the coating generates hydroxyapatite Ca10(PO46(OH2. After a long immersion, the coating became dense and provided an effective corrosion resistance compared with the mild steel rebar. Secondly, the coated and uncoated steel rebars embedded in mortar and immersed in chloride solution showed no corrosion or deterioration of the coated steel. Corrosion rate is considerably lowered by this phosphate coating.

  18. Waste of cleaning emulsion sewage as inhibitors of steel corrosion

    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.

  19. Oxide and nitride protective layers formed on stainless steel by thermal treatment: SEM, AES, WDS and corrosion measurements

    Jenko, M.

    2008-04-01

    Full Text Available Protective oxide and/or nitride layers on AISI 321 stainless steel were prepared by thermal treatment in air and two controlled atmospheres in a laboratory simulation of an actual technological procedure. Samples’ surface was imaged by Scanning Electron Microscopy (SEM, elemental composition of the substrates was checked by Wavelength Dispersive Spectroscopy (WDS and depth profiles of the samples were measured by Auger Electron Spectroscopy (AES. Since protective layer thicknesses were found to be of the order of hundreds of nanometers an attempt was made to obtain some fast averaged information about layers composition by Wavelength Dispersive Spectroscopy (WDS with appropriately adjusted primary beam energy. Electrochemical corrosion testing was also performed on samples.

  20. Atmospheric corrosion of mild steel

    Morcillo, Manuel; Fuente, Daniel de la; Díaz Ocaña, Iván; Cano, Heidis

    2011-01-01

    The atmospheric corrosion of mild steel is an extensive topic that has been studied by many authors in different regions throughout the world. This compilation paper incorporates relevant publications on the subject, in particular about the nature of atmospheric corrosion products, mechanisms of atmospheric corrosion and kinetics of the atmospheric corrosion process, paying special attention to two matters upon which relatively less information has been published: a) the morpholog...

  1. Multilayer graphene for long-term corrosion protection of stainless steel bipolar plates for polymer electrolyte membrane fuel cell

    Stoot, Adam Carsten; Camilli, Luca; Spiegelhauer, Susie Ann;

    2015-01-01

    Abstract Motivated by similar investigations recently published (Pu et al., 2015), we report a comparative corrosion study of three sets of samples relevant as bipolar plates for polymer electrolyte fuel cells: stainless steel, stainless steel with a nickel seed layer (Ni/SS) and stainless steel...... graphene film is still intact with unchanged defect density. Our results show that even non-perfect multilayer graphene films can considerably increase the lifetime of future-generation bipolar plates for fuel cells....

  2. Corrosion protection of steel by thin coatings of starch-oil dry lubricants

    Corrosion of materials is one of the most serious and challenging problems faced worldwide by industry. Dry lubricants reduce friction between two metal surfaces. This research investigated the inhibition of corrosive behavior a dry lubricant formulation consisting of jet-cooked corn starch and soyb...

  3. Recent Natural Corrosion Inhibitors for Mild Steel: An Overview

    Marko Chigondo

    2016-01-01

    Full Text Available Traditionally, reduction of corrosion has been managed by various methods including cathodic protection, process control, reduction of the metal impurity content, and application of surface treatment techniques, as well as incorporation of suitable alloys. However, the use of corrosion inhibitors has proven to be the easiest and cheapest method for corrosion protection and prevention in acidic media. These inhibitors slow down the corrosion rate and thus prevent monetary losses due to metallic corrosion on industrial vessels, equipment, or surfaces. Inorganic and organic inhibitors are toxic and costly and thus recent focus has been turned to develop environmentally benign methods for corrosion retardation. Many researchers have recently focused on corrosion prevention methods using green inhibitors for mild steel in acidic solutions to mimic industrial processes. This paper provides an overview of types of corrosion, corrosion process, and mainly recent work done on the application of natural plant extracts as corrosion inhibitors for mild steel.

  4. Layered double hydroxides as containers of inhibitors in organic coatings for corrosion protection of carbon steel

    Hang, To Thi Xuan; Truc, Trinh Anh; Duong, Nguyen Thuy; Pébère, Nadine; Olivier, Marie-Georges

    2012-01-01

    International audience The present work focuses on the use of layered double hydroxides (LDH) as containers for corrosion inhibitors in an epoxy coating. 2-Benzothiazolylthio-succinic acid (BTSA), used as corrosion inhibitor, was intercalated by co-precipitation in magnesium-aluminum layered double hydroxides. The obtained LDH-BTSA was characterized by infrared spectroscopy, X-ray diffraction and scanning electron microscopy. BTSA release from LDH-BTSA in NaCl solutions was investigated by...

  5. An efficient protection of stainless steel against corrosion: Combination of a conversion layer and titanium dioxide deposit

    Bamoulid, Loubna; Maurette, Marie-Thérèse; De Caro, Dominique; Guenbour, Abdellah; Ben Bachir, Ali; Aries, Lucien; El hajjaji, Souad; Benoit-Marquié, Florence; Ansart, Florence

    2008-01-01

    In the present work, a novel process has been developed to improve the corrosion properties of ferritic stainless steels. Titanium oxide coatings have been deposited onto stainless steel by sol–gel process after a pre-functionalization of the substrate in a conversion bath. Gel titania was prepared by hydrolysis of a titanium butoxide through a sol–gel process. Duplex systems "conversion layer/uniform TiO2 coating" have been prepared on stainless steels using a dipping technique and thermal p...

  6. Electrochemical, atomic force microscopy and infrared reflection absorption spectroscopy studies of pre-formed mussel adhesive protein films on carbon steel for corrosion protection

    Zhang, Fan, E-mail: fanzhang@kth.se [KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Div. of Surface and Corrosion Science, Drottning Kristinas vaeg.51, SE-100 44 Stockholm (Sweden); Pan, Jinshan [KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Div. of Surface and Corrosion Science, Drottning Kristinas vaeg.51, SE-100 44 Stockholm (Sweden); Claesson, Per Martin [KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Div. of Surface and Corrosion Science, Drottning Kristinas vaeg.51, SE-100 44 Stockholm (Sweden); Institute for Surface Chemistry, P.O. Box 5607, SE-114 86 Stockholm (Sweden); Brinck, Tore [KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Physical Chemistry, Division of Physical Chemistry, Teknikringen 36, SE-10044 Stockholm (Sweden)

    2012-10-01

    Electrochemical measurements, in situ and ex situ atomic force microscopy (AFM) experiments and infrared reflection absorption spectroscopy (IRAS) analysis were performed to investigate the formation and stability as well as corrosion protection properties of mussel adhesive protein (Mefp-1) films on carbon steel, and the influence of cross-linking by NaIO{sub 4} oxidation. The in situ AFM measurements show flake-like adsorbed protein aggregates in the film formed at pH 9. The ex situ AFM images indicate multilayer-like films and that the film becomes more compact and stable in NaCl solution after the cross-linking. The IRAS results reveal the absorption bands of Mefp-1 on carbon steel before and after NaIO{sub 4} induced oxidation of the pre-adsorbed protein. Within a short exposure time, a certain corrosion protection effect was noted for the pre-formed Mefp-1 film in 0.1 M NaCl solution. Cross-linking the pre-adsorbed film by NaIO{sub 4} oxidation significantly enhanced the protection efficiency by up to 80%. - Highlights: Black-Right-Pointing-Pointer Mussel protein was tested as 'green' corrosion protection strategy for steel. Black-Right-Pointing-Pointer At pH 9, the protein adsorbs on carbon steel and forms a multilayer-like film. Black-Right-Pointing-Pointer NaIO{sub 4} leads to structural changes and cross-linking of the protein film. Black-Right-Pointing-Pointer Cross-linking results in a dense and compact film with increased stability. Black-Right-Pointing-Pointer Cross-linking of preformed film significantly enhances the corrosion protection.

  7. Electrochemical, atomic force microscopy and infrared reflection absorption spectroscopy studies of pre-formed mussel adhesive protein films on carbon steel for corrosion protection

    Electrochemical measurements, in situ and ex situ atomic force microscopy (AFM) experiments and infrared reflection absorption spectroscopy (IRAS) analysis were performed to investigate the formation and stability as well as corrosion protection properties of mussel adhesive protein (Mefp-1) films on carbon steel, and the influence of cross-linking by NaIO4 oxidation. The in situ AFM measurements show flake-like adsorbed protein aggregates in the film formed at pH 9. The ex situ AFM images indicate multilayer-like films and that the film becomes more compact and stable in NaCl solution after the cross-linking. The IRAS results reveal the absorption bands of Mefp-1 on carbon steel before and after NaIO4 induced oxidation of the pre-adsorbed protein. Within a short exposure time, a certain corrosion protection effect was noted for the pre-formed Mefp-1 film in 0.1 M NaCl solution. Cross-linking the pre-adsorbed film by NaIO4 oxidation significantly enhanced the protection efficiency by up to 80%. - Highlights: ► Mussel protein was tested as “green” corrosion protection strategy for steel. ► At pH 9, the protein adsorbs on carbon steel and forms a multilayer-like film. ► NaIO4 leads to structural changes and cross-linking of the protein film. ► Cross-linking results in a dense and compact film with increased stability. ► Cross-linking of preformed film significantly enhances the corrosion protection.

  8. Development of Nb2O5|Cu composite as AISI 1020 steel thermal spray coating for protection against corrosion by soil in buried structures

    An Nb2O|Cu corrosion-resistant coating was developed and applied onto AISI 1020 steel substrate by Powder Flame Spray. A galvanostatic electrochemical technique was employed, with and without ohmic drop, in four different soils (two corrosively aggressive and two less aggressive). Behavior of coatings in different soils was compared using a cathodic hydrogen reduction reaction (equilibrium potential, overvoltage and exchange current density) focusing on the effect of ohmic drop. Results allow recommendation of Nb2O5|Cu composite for use in buried structure protection. (author)

  9. Evaluation of the protection behaviour of reinforcement steel against corrosion induced by chlorides in reinforced mortar specimens; Avaliacao do comportamento frente a corrosao pelo ataque de cloreto de argamassa armada apos varios tratamentos protetores

    Crivelaro, Marcos

    2002-07-01

    In this work various treatments for protecting reinforcing steels against corrosion induced by chlorides have been evaluated. Additives to mortars and surface treatments given to reinforcing steels were evaluated as corrosion protection measures. In the preliminary tests the corrosion resistance of a CA 50 steel treated by immersion in nearly 50 different solutions, was determined. The solutions were prepared with tannins (from various sources) and/or benzotriazole, and during immersion, a surface film formed on the steel. The corrosion resistance of the coated steels was evaluated in a saturated Ca(OH){sub 2} solution with 5% (wt) NaCl. Preliminary tests were also carried out with mortars reinforced with uncoated steel to which tannin or lignin was added. Two organic coatings, a monocomponent and a bicomponent type, formulated specially for this investigation, with both tannin and benzotriazole, were also tested in the preliminary tests to select the coating with better corrosion protection property. The bicomponent type (epoxy coating) showed better performance than the monocomponent type coating, and the former was therefore chosen to investigate the corrosion performance on CA 50 steel inside mortar specimens. From the preliminary tests, two solutions with tannin from two sources, Black Wattle (Acacia mearnsii) and Brazilian tea (Ilex paraguariensis St. Hill), to which benzotriazole and phosphoric acid were added, were chosen. Mortar specimens reinforced with CA50 steel treated by immersion in these two solutions were prepared. Also, epoxy coated CA50 steel was tested as reinforcement inside mortar specimens. Mortars reinforced with uncoated CA50 steel were also prepared and corrosion tested for comparison. The effect of tannin and lignin as separate additives to the mortar on the corrosion resistance of uncoated steel was also studied. The reinforced mortar specimens were tested with various cycles of immersion for 2 days in 3.5% (wt) NaCl followed by with air

  10. Marine corrosion of mild steel at Lumut, Perak

    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.

  11. Multilayer Al{sub 2}O{sub 3}/TiO{sub 2} Atomic Layer Deposition coatings for the corrosion protection of stainless steel

    Marin, E., E-mail: elia.marin@uniud.it [University of Udine, 33100 Udine (Italy); Guzman, L.; Lanzutti, A. [University of Udine, 33100 Udine (Italy); Ensinger, W. [Darmstadt Technolnische Universitaet, 06151 Germany (Germany); Fedrizzi, L. [University of Udine, 33100 Udine (Italy)

    2012-11-01

    Atomic Layer Deposition (ALD) is used to deposit conformal nanometric layers onto different substrates. In this paper, characterization of different ALD layers has been carried out in order to evaluate the suitability of this deposition technolnique for the corrosion protection of stainless steel substrates. Al{sub 2}O{sub 3}, TiO{sub 2} and multilayer configurations, have been deposited on AISI 316 austenitic stainless steel and have then been investigated using atomic force microscopy (AFM), glow discharge optical emission spectrometry (GDOES), scanning electron microscopy (SEM), Vickers indentation and potentiodynamic polarizations (PP). AFM has been used to obtain a morphological characterization and to evaluate the thickness of the depositions. SEM has been used to investigate the presence of deposition defects. GDOES has been used to obtain a compositional profile. Vickers indentations were used in order to evaluate the resistance to delamination. PPs have been used in order to evaluate the corrosion protection. The results have showed that corrosion resistance can be effectively enhanced. Multilayer configuration proved to be more effective than single layers configurations. - Highlights: Black-Right-Pointing-Pointer Atomic Layer Deposition (ALD) coatings with different thicknesses were tested. Black-Right-Pointing-Pointer Glow Discharge Optical Emission Spectroscopy gave in-depth composition profiles. Black-Right-Pointing-Pointer Corrosion resistance was strongly enhanced by ALD. Black-Right-Pointing-Pointer Coating to substrate adhesion was improved for thin and multilayer coatings. Black-Right-Pointing-Pointer Multilayer ALD configurations proved to be more protective than single layers.

  12. Corrosion protection of cold-rolled steel with alkyd paint coatings composited with submicron-structure types polypyrrole-modified nano-size alumina and carbon nanotubes

    Highlights: ► Alumina/carbon nanotube (CNT) supported polypyrrole (PPy) particles were prepared. ► Various paint compositions with alkyd binder were immersion tested. ► Alumina-supported PPy based coating provided steel protection in NaCl solution. ► Polyelectrolyte modified CNT embedded coating afforded long-term stable protection. ► sulphonated CNT loaded coating indicated firm corrosion resistance in HCL solution. ► Results are interpreted on the basis of nano and microstructure of the particles. - Abstract: This paper is focused on studying corrosion protection of cold-rolled steel with alkyd paint coatings comprising nano-size alumina and either polystyrene-sulphonate (PSS) modified or sulphonated multi-walled carbon nanotube (MWCNT) supported polypyrrole (PPy). Single layer coatings (in thickness of 40 ± 5 μm) comprising PPy deposited alumina and PSS modified MWCNT supported PPy afforded viable protection during the 1 M sodium chloride test. The coatings containing PSS modified and weakly sulphonated MWCNTs (at volume fractions of 9.9 × 10−4 and 2.5 × 10−4) with PPy volume fractions of 3.5 × 10−3 and 2.5 × 10−3 provided effective corrosion prevention during the 1 M sodium chloride and hydrochloric acid solution tests. While inhibitor particles were characterised by infrared spectroscopy, corrosion products formed at the paint–steel interface were studied by X-ray photoelectron spectroscopy. Apart from the electron microscopy observations, rheology study of three-dimensional structure of the inhibitor particles was performed in dispersions at similar compositions to those used for the paint formulations. Thus, protection mechanism relating to both types of immersion tests is discussed in terms of properties of the inhibitor particles and their microstructure in the coatings.

  13. Some peculiarities of corrosion of wheel steel

    Alexander SHRAMKO; Alfred KOZLOWSKY; Elena BELAJA; Yuriy PROIDAK; Pinchuk, Sofia; Gubenko, Svetlana

    2009-01-01

    Corrosion mechanism and rate of different chemical composition and structural condition of wheel steel were investigated. It was shown that “white layers”, variation in grain size and banding of wheel steel structure results in corrosion rate. Microstructure of steel from different elements of railway wheels after operation with corrosion was investigated. Wheel steel with addition of vanadium corroded more quickly than steel without vanadium. Non-metallic inclusions are the centre of corrosi...

  14. Atmospheric corrosion of mild steel

    Morcillo, M.

    2011-10-01

    Full Text Available The atmospheric corrosion of mild steel is an extensive topic that has been studied by many authors in different regions throughout the world. This compilation paper incorporates relevant publications on the subject, in particular about the nature of atmospheric corrosion products, mechanisms of atmospheric corrosion and kinetics of the atmospheric corrosion process, paying special attention to two matters upon which relatively less information has been published: a the morphology of steel corrosion products and corrosion product layers; and b long-term atmospheric corrosion ( > 10 years.

    La corrosión atmosférica del acero suave es un tema de gran amplitud que ha sido tratado por muchos autores en numerosas regiones del mundo. Este artículo de compilación incorpora publicaciones relevantes sobre esta temática, en particular sobre la naturaleza de los productos de corrosión atmosférica, mecanismos y cinética de los procesos de corrosión atmosférica, prestando una atención especial a dos aspectos sobre los que la información publicada ha sido menos abundante: a morfología de los productos de corrosión del acero y capas de productos de corrosión, y b corrosión atmosférica a larga duración (> 10 años.

  15. Protection of Mild Steel Against Sulphides Corrosion In Petroleum Oil Industry

    The aggressive properties of the media encountered when drilling for oil derive from the fact that they contain an abundance of mineralized water, as well as hydrogen sulphide and carbon dioxide. Particularly vulnerable to corrosion and installation of old deposits, where highly mineralized water or sometimes even sea water, is pumped into the bed so as to increase the oil yield, and where acid treatment is also carried out, the injection of such water into the bed creates favourable conditions for the development of microbiological processes promoting the life activity of sulphate-reducing bacteria and contributing to the appearance of hydrogen sulphide in the system

  16. Investigation on the Effect of Green Inhibitors for Corrosion Protection of Mild Steel in 1 M NaOH Solution

    Premjith Jayakumar Ramakrishnan

    2014-01-01

    Full Text Available Alkaline corrosion is one of the main issues faced by the industries. The main chemicals abundantly used in industries are NaOH, H3PO4, HCl, and H2SO4. Corrosion control of metals has technical, economical, environmental, and aesthetical importance. The use of inhibitors is one of the best options to protect metals and alloys against corrosion. The corrosion protection of mild steel in 1 M NaOH solution by mix of Henna/Zeolite powder was studied at different temperatures by weight loss technique. Adsorption, activation, and statistical studies were addressed in this work. Adsorption studies showed that inhibitor adsorbed on metal surface according to Langmuir isotherm. Surface studies were performed by using UV-spectra and SEM. The adsorption of inhibitor on the steel surface was found to obey Langmuir’s adsorption isotherm. The inhibition efficiency increased with increasing concentration of the inhibitor in NaOH medium. Inhibition mechanism is deduced from the concentration and temperature dependence of the inhibition efficiency, Langmuir’s adsorption isotherm, SEM, and UV spectroscopic results.

  17. Steel corrosion in radioactive waste storage tanks

    A collaborative study is being conducted by CNEA and USDOE (Department of Energy of the United States of America) to investigate the effects of tank waste chemistry on radioactive waste storage tank corrosion. Radioactive waste is stored in underground storage tanks that contain a combination of salts, consisting primarily of sodium nitrate, sodium nitrite and sodium hydroxide. The USDOE, Office of River Protection at the Hanford Site, has identified a need to conduct a laboratory study to better understand the effects of radioactive waste chemistry on the corrosion of waste storage tanks at the Hanford Site. The USDOE science need (RL-WT079-S Double-Shell Tanks Corrosion Chemistry) called for a multi year effort to identify waste chemistries and temperatures within the double-shell tank (DST) operating limits for corrosion control and operating temperature range that may not provide the expected corrosion protection and to evaluate future operations for the conditions outside the existing corrosion database. Assessment of corrosion damage using simulated (non-radioactive) waste is being made of the double-shell tank wall carbon steel alloy. Evaluation of the influence of exposure time, and electrolyte composition and/or concentration is being also conducted. (author)

  18. Cathodic protection to control microbiologically influenced corrosion

    Information about the cathodic protection performance in environments with microbiologically influenced corrosion (MIC) effects is very fragmented and often contradictory. Not enough is known about the microbial effects on cathodic protection effectiveness, criteria, calcareous deposits, corrosion rates and possible hydrogen embrittlement of titanium and some stainless steel condenser tubes. This paper presents a review of cathodic protection systems, describes several examples of cathodic protection in environments with MIC effects and provides preliminary conclusions about cathodic protection design parameters, criteria and effectiveness in MIC environments. 30 refs

  19. Electrochemical and analytical study of some organic inhibitors used for carbon steel corrosion protection in water cooling systems

    Water is the main cooling fluid in most industrial applications due to its wide existence in nature and its high specific heat capacity and its thermal conductivity. If pure water was used in cooling systems no problems will occur. However, due to the presence of suspended matter and dissolved solids and gases in water three main problems are encountered in industrial cooling systems; corrosion, scale, and growth of microorganisms which all badly affect the heat transfer efficiency of such system. This study is concerned with utilizing organic inhibitors to control corrosion of mild steel. Three inhibitors were used; 1-hydroxyethylene-1,1- diphosphonic acid (HEDP) as an example of phosphonates, sodium octanoate (C7H15-COONa)as an examples of carboxylates, and 2- phosphono-butane -1,2,4-tricarboxylic acid (PBTC) as an example of a compound having two effective groups: carboxylate and phosphonate (PBTC). City water available at site was used in the present study as a large number of cooling systems utilize water available at site together with mechanical and chemical treatment methods to control corrosion among the two other problems. Two experimental techniques were utilized, potentiodynamic polarization technique and gravimetric technique. The gravimetric technique included a flow loop to simulate the flowing condition of a cooling circuit and a one-day immersion test. Carbon steel specimens, polished to 120 and 600 grit size were used to investigate the effect of surface roughness on the corrosion inhibition efficiency.

  20. BWR steel containment corrosion

    The report describes regulatory actions taken after corrosion was discovered in the drywell at the Oyster Creek Plant and in the torus at the Nine Mile Point 1 Plant. The report describes the causes of corrosion, requirements for monitoring corrosion, and measures to mitigate the corrosive environment for the two plants. The report describes the issuances of generic letters and information notices either to collect information to determine whether the problem is generic or to alert the licensees of similar plants about the existence of such a problem. Implementation of measures to enhance the containment performance under severe accident conditions is discussed. A study by Brookhaven National Laboratory (BNL) of the performance of a degraded containment under severe accident conditions is summarized. The details of the BNL study are in the appendix to the report

  1. Effect of magnetite as a corrosion product on the corrosion of carbon steel overpack

    It is necessary to clear the effects of corrosion products on the corrosion life time of carbon steel overpack for geological isolation of high-level radioactive waste (HLW). Especially, it is important to understand the effects of magnetite because magnetite as a simulated corrosion product is reported to accelerate the corrosion rate of carbon steel. In this study, corrosion tests to reproduce the acceleration of corrosion due to magnetite was performed and the mechanism of the acceleration was investigated to evaluate the effects of magnetite as a corrosion product. Based on the results of experiments, following conclusions are obtained; (1) Magnetite powder accelerates the corrosion rate of carbon steel. The main reaction of corrosion under the presence of magnetite is the reduction of Fe(III) in magnetite to Fe(II), but the reaction of hydrogen generation is also accelerated. The contribution of hydrogen generation reaction was estimated to be about 30% in the total corrosion reaction based on the experimental result of immersion test under the presence of magnetite. (2) Actual corrosion products containing magnetite generated by the corrosion of carbon steel protect the metal from the propagation of corrosion. The corrosion depth of carbon steel overpack due to magnetite was estimated to be about 1 mm based on the results of experiments. Even if the effect of magnetite is taken into the assessment of corrosion lifetime of overpack, total corrosion depth in 1000 years is estimated to be 33 mm, which is smaller than the corrosion allowance of 40 mm described in the second progress report on research and development for the geological disposal of HLW in Japan. It was concluded that the effect of magnetite on the corrosion life time of carbon steel overpack is negligible. (author)

  2. Atmospheric corrosion of carbon steel in the prairie regions

    Shaw, W.J. [Calgary Univ., AB (Canada). Dept. of Mechanical and Manufacturing Engineering; Andersson, J.I. [Husky Oil Operations Ltd., Calgary, AB (Canada)

    2010-07-01

    A study of atmospheric corrosion and carbon steel located in the prairie regions of Canada was presented. The study considered corrosion behaviour as well as the standards currently used to establish and predict corrosion in atmospheric conditions. The aim of the study was to develop an accurate predictive method of establishing corrosion amounts over time. The controlling parameters for atmospheric corrosion included acidic rainfall; temperature and humidity; time of wetness; and the presence of major contaminants such as sulfur dioxide (SO{sub 2}). The predictive approach involved the study of a protective film of magnetite iron oxide that establishes itself on carbon steel over time. The presence of the film provides increased atmospheric corrosion resistance. An analysis of the atmospheric corrosion of steel tanks at the Hardisty terminal was used to demonstrate the method. 22 refs., 5 tabs., 7 figs.

  3. Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel

    Hilbert, Lisbeth Rischel

    2000-01-01

    Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria, e.g. on pipelines buried in soil and on marine structures. MIC of carbon steel must be monitored on-line in order to provide an efficient protection and...... control the corrosion. A number of monitoring techniques is industrially used today, and the applicability and reliability of these for monitoring MIC is evaluated. Coupons and ER are recommended as necessary basic techniques even though localised corrosion rate cannot be measured. FSM measures general...... corrosion and detects localised corrosion, but the sensitivity is not high enough for monitoring initiation of pitting and small attacks. Electrochemical techniques as LPR and EIS give distorted data and unreliable corrosion rates, when biofilm and corrosion products cover the steel surface. However, EIS...

  4. Volatile corrosion inhibitor film formation on carbon steel surface and its inhibition effect on the atmospheric corrosion of carbon steel

    A novel volatile corrosion inhibitor (VCI), bis-piperidiniummethyl-urea (BPMU), was developed for temporary protection of carbon steel. Its vapor corrosion inhibition property was evaluated under simulated operational conditions. Electrochemical impedance spectroscopy was applied to study the inhibition effect of BPMU on the corrosion of carbon steel with a thin stimulated atmospheric corrosion water layers. Adsorption of BPMU on carbon steel surfaces was investigated by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The results indicate that BPMU can form a protective film on the metal surface, which protects the metal against further corrosion. The structure of the protective film was suggested as one BPMU molecule chelated with one Fe atom to form a complex with two hexa-rings

  5. Volatile corrosion inhibitor film formation on carbon steel surface and its inhibition effect on the atmospheric corrosion of carbon steel

    Zhang, Da-quan; An, Zhong-xun; Pan, Qing-yi; Gao, Li-xin; Zhou, Guo-ding

    2006-11-01

    A novel volatile corrosion inhibitor (VCI), bis-piperidiniummethyl-urea (BPMU), was developed for temporary protection of carbon steel. Its vapor corrosion inhibition property was evaluated under simulated operational conditions. Electrochemical impedance spectroscopy was applied to study the inhibition effect of BPMU on the corrosion of carbon steel with a thin stimulated atmospheric corrosion water layers. Adsorption of BPMU on carbon steel surfaces was investigated by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The results indicate that BPMU can form a protective film on the metal surface, which protects the metal against further corrosion. The structure of the protective film was suggested as one BPMU molecule chelated with one Fe atom to form a complex with two hexa-rings.

  6. Corrosion of carbon steel welds

    This report assesses the factors which cause preferential attack to occur in carbon steel fusion welds. It was concluded that the main factors were: the inclusion content of the weld metal, the potential of the weld metal being less noble than that of the parent, and the presence of low-temperature transformation products in the heat-affected zone of the weld. These factors should be minimized or eliminated as appropriate so that the corrosion allowances determined for carbon steel waste drums is also adequate for the welds. An experimental/theoretical approach is recommended to evaluate the relative corrosion resistance of welds prepared from BS 4360 grade 43A steel to that of the parent material. (author)

  7. Inhibition of the Corrosion of Mild Steel in Acid Media by Naturally Occurring Acacia Senegal

    Urvija Garg; Tak, R. K.

    2010-01-01

    The inhibition of corrosion of mild steel in HCl solution by naturally occurring Acacia Senegal has been studied in relation to the concentration of inhibitor and concentration of corrosive medium. It has been observed that the Acacia Senegal alcoholic extract acts as a good corrosion inhibitor in hydrochloric acid solution and the adsorption of the extract provides a good protection against mild steel corrosion.

  8. Corrosion behavior of 2205 duplex stainless steel.

    Platt, J A; Guzman, A; Zuccari, A; Thornburg, D W; Rhodes, B F; Oshida, Y; Moore, B K

    1997-07-01

    The corrosion of 2205 duplex stainless steel was compared with that of AISI type 316L stainless steel. The 2205 stainless steel is a potential orthodontic bracket material with low nickel content (4 to 6 wt%), whereas the 316L stainless steel (nickel content: 10 to 14 wt%) is a currently used bracket material. Both stainless steels were subjected to electrochemical and immersion (crevice) corrosion tests in 37 degrees C, 0.9 wt% sodium chloride solution. Electrochemical testing indicates that 2205 has a longer passivation range than 316L. The corrosion rate of 2205 was 0.416 MPY (milli-inch per year), whereas 316L exhibited 0.647 MPY. When 2205 was coupled to 316L with equal surface area ratio, the corrosion rate of 2205 reduced to 0.260 MPY, indicating that 316L stainless steel behaved like a sacrificial anode. When 316L is coupled with NiTi, TMA, or stainless steel arch wire and was subjected to the immersion corrosion test, it was found that 316L suffered from crevice corrosion. On the other hand, 2205 stainless steel did not show any localized crevice corrosion, although the surface of 2205 was covered with corrosion products, formed when coupled to NiTi and stainless steel wires. This study indicates that considering corrosion resistance, 2205 duplex stainless steel is an improved alternative to 316L for orthodontic bracket fabrication when used in conjunction with titanium, its alloys, or stainless steel arch wires. PMID:9228844

  9. MECHANICAL PROPERTIES AND CORROSION PROTECTION OF CARBON STEEL COATED WITH AN EPOXY BASED POWDER COATING CONTAINING MONTMORILONITE FUNCTIONALIZED WITH SILANE

    Paula Tibola Bertuoli

    2014-06-01

    Full Text Available In the present work the MMT-Na+ clay was functionalized with 3-aminopropyltriethoxysilane (γ-APS and incorporated in a commercial formulation epoxy-based powder coating in a proportion of 8 wt% and applied on 1008 carbon steel panels by electrostatic spray. Adhesion, flexibility, impact and corrosion performance in salt spray chamber tests were performed to evaluate the coatings. The presence of clay did not affect the mechanical properties of the film, however greater subcutaneous migration was assessed after the completion of salt spray testing, which can compromise the use of paints obtained as primers.

  10. Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel

    Hilbert, Lisbeth Rischel

    2000-01-01

    Abstract Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria, e.g. on pipelines buried in soil and on marine structures. MIC of...... carbon steel must be monitored on-line in order to provide an efficient protection and control the corrosion. A number of monitoring techniques is industrially used today, and the applicability and reliability of these for monitoring MIC is evaluated. Coupons and ER are recommended as necessary basic...... techniques even though localised corrosion rate cannot be measured. FSM measures general corrosion and detects localised corrosion, but the sensitivity is not high enough for monitoring initiation of pitting and small attacks. Electrochemical techniques as LPR and EIS give distorted data and unreliable...

  11. Study on cerium-doped nano-TiO2 coatings for corrosion protection of 316 L stainless steel.

    Li, Suning; Wang, Qian; Chen, Tao; Zhou, Zhihua; Wang, Ying; Fu, Jiajun

    2012-01-01

    Many methods have been reported on improving the photogenerated cathodic protection of nano-TiO2 coatings for metals. In this work, nano-TiO2 coatings doped with cerium nitrate have been developed by sol-gel method for corrosion protection of 316 L stainless steel. Surface morphology, structure, and properties of the prepared coatings were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. The corrosion protection performance of the prepared coatings was evaluated in 3 wt% NaCl solution by using electrochemical techniques in the presence and absence of simulated sunlight illumination. The results indicated that the 1.2% Ce-TiO2 coating with three layers exhibited an excellent photogenerated cathodic protection under illumination attributed to the higher separation efficiency of electron-hole pairs and higher photoelectric conversion efficiency. The results also showed that after doping with an appropriate concentration of cerium nitrate, the anti-corrosion performance of the TiO2 coating was improved even without irradiation due to the self-healing property of cerium ions. PMID:22515192

  12. Tantalum oxide nanocoatings prepared by atomic layer and filtered cathodic arc deposition for corrosion protection of steel: Comparative surface and electrochemical analysis

    Highlights: ► 50 nm Ta2O5 coatings grown by ALD at 160 °C and FCAD for protection of steel. ► Combined analysis by ToF-SIMS, XPS, polarization curves and EIS. ► Relation between chemical architecture and corrosion protection properties studied. ► Localized corrosion by pitting with absence of coating dissolution demonstrated. ► Origin and role of spurious interfacial oxide promoting coating breakdown emphasized. -- Abstract: A comparative study by Time-of-Flight Secondary Ions Mass Spectrometry and X-ray Photoelectron Spectroscopy, i–E polarization curves and Electrochemical Impedance Spectroscopy of the corrosion protection of low alloy steel by 50 nm thick tantalum oxide coatings prepared by low temperature Atomic Layer Deposition (ALD) and Filtered Cathodic Arc Deposition (FCAD) is reported. The data evidence the presence of a spurious oxide layer mostly consisting of iron grown by transient thermal oxidation at the ALD film/substrate interface in the initial stages of deposition and its suppression by pre-treatment in the FCAD process. Carbonaceous contamination (organic and carbidic) resulting from incomplete removal of the organic precursor is the major cause of the poorer sealing properties of the ALD film. No coating dissolution is demonstrated in neutral or acid 0.2 M NaCl solutions. In acid solution localized corrosion by pitting proceeds faster with the ALD than with the FCAD coating. The roles of the pre-existing channel defects exposing the substrate surface and of the spurious interfacial oxide promoting coating breakdown and/or delamination are emphasized

  13. Tests Of Protective Coats For Carbon Steel

    Macdowell, Louis G., III

    1995-01-01

    Report describes laboratory and field tests of candidate paints (primers, tie coats, and topcoats) for use in protecting carbon-steel structures against corrosion in seaside environment at Kennedy Space Center. Coating materials selected because of utility in preventing corrosion, also on basis of legal requirements, imposed in several urban areas, for reduction of volatile organic contents.

  14. Synthesis and Application of Hybrid Polymer Composites Based on Silver Nanoparticles as Corrosion Protection for Line Pipe Steel

    Ayman M. Atta

    2014-05-01

    Full Text Available A facile method was developed to synthesize in high yield dispersed silver nanoparticles (AgNPs with small particle sizes of less than 10 nm. Silver nitrate was reduced to silver nanoparticles by p-chloroaniline in the presence of polyoxyethylene maleate 4-nonyl-2-propylene-phenol (NMA as a stabilizer. The produced AgNPs were used to prepare hybrid polymer based on N-isopropylacrylamide (NIPAm, 2-acrylamido-2-methylpropane sulfonic acid (AMPS, N,N-methylenebisacrylamide (MBA and potassium persulfate (KPS using a semi-batch solution polymerization method. The prepared AgNPs and hybrid polymer were characterized by Fourier transform infrared (FTIR spectroscopy, X-ray diffraction (XRD patterns and transmission electron microscopy (TEM. The corrosion inhibition activity of the AgNPs and hybrid polymer towards steel corrosion in the presence of hydrochloric acid has been investigated by polarization and electrochemical impedance spectroscopy (EIS methods. Polarization measurements indicate that the AgNPs and hybrid polymer acts as a mixed type-inhibitor and the inhibition efficiency increases with inhibitor concentration. The results of potentiodynamic polarization and EIS measurements clearly showed that the inhibition mechanism involves blocking of the steel surface by inhibitor molecules via adsorption.

  15. Assessing resistance of stabilized corrosion resistant steels to intergranular corrosion

    Resistance to intergranular corrosion was determined for four types of titanium-stabilized steels from the coefficients of stabilization efficiency according to the degree the chemical composition was known. The ATA SUPER steel showed the highest resistance parameter value. The resistance of this type of steel of a specific composition, showing a relatively low value of mean nitrogen content was compared with steel of an optimized chemical composition and with low-carbon niobium stabilized, molybdenum modified steels. The comparison showed guarantees of a sufficient resistance of the steel to intergranular corrosion. The method of assessing the resistance to intergranular corrosion using the calculation of the minimum content of Cr', i.e., the effective chromium content, and the maximum effective carbon content C' giving the resistance parameter k seems to be prospective for practical use in the production of corrosion resistant steels. (author). 1 tab., 5 figs., 15 refs

  16. Marine atmospheric corrosion of carbon steels

    Morcillo, Manuel; Alcántara, Jenifer; Díaz, Iván; Chico, Belén; Simancas, Joaquín; de la Fuente, Daniel

    2015-01-01

    Basic research on marine atmospheric corrosion of carbon steels is a relatively young scientific field and there continue to be great gaps in this area of knowledge. The presence of akaganeite in the corrosion products that form on steel when it is exposed to marine atmospheres leads to a notable increase in the corrosion rate. This work addresses the following issues: (a) environmental conditions necessary for akaganeite formation; (b) characterisation of akaganeite in the corrosion products...

  17. Pitting corrosion protection of low nickel stainless steel by electropolymerized conducting polymer coating in 0.5 M NaCl solution

    T Dhanabal; G Amirthaganesan; J Ravichandran

    2011-06-01

    Conducting polymers of polyaniline (PANi) and poly(o-phenylenediamine) (PoPD) were electropolymerized by cyclic voltammetric technique on low nickel stainless steel (LN SS) in H2SO4 solution containing aniline and -phenylenediamine monomers. The coatings were characterized by Fourier transform infrared spectroscopy, UV-visible and scanning electron microscopic techniques and the results are discussed. The corrosion protective properties of PANi and PoPD coatings on LN SS in 0.5 M NaCl were evaluated using potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) techniques. The potentiodynamic polarization and electrochemical impedance spectroscopic results indicate that the PoPD coating inhibits the corrosion of LN SS in 0.5 M NaCl solution more effectively than PANi.

  18. Monitoring corrosion of steel bars in reinforced concrete structures.

    Verma, Sanjeev Kumar; Bhadauria, Sudhir Singh; Akhtar, Saleem

    2014-01-01

    Corrosion of steel bars embedded in reinforced concrete (RC) structures reduces the service life and durability of structures causing early failure of structure, which costs significantly for inspection and maintenance of deteriorating structures. Hence, monitoring of reinforcement corrosion is of significant importance for preventing premature failure of structures. This paper attempts to present the importance of monitoring reinforcement corrosion and describes the different methods for evaluating the corrosion state of RC structures, especially hal-cell potential (HCP) method. This paper also presents few techniques to protect concrete from corrosion. PMID:24558346

  19. 不锈钢管材蒸汽发生器的腐蚀与防护%Corrosion and protection of stainless steel tube material steam generator

    丁训慎

    2009-01-01

    This paper describes stainless steel tube material and corrosion form Shippingport No.1 Nclear Power Plant, vertical steam generator of some nuclear-powered equipment and horizontal steam generator,using several protection measures of stainless steel tube material steam generator.%介绍了蒸汽发生器不锈钢管材及其腐蚀形式,美国西屋公司希平港1号核电厂蒸汽发生器、我国某核动力装置立式蒸汽发生器和卧式蒸汽发生器的腐蚀,对不锈钢管材蒸汽发生器的多项防护措施.

  20. Thermally Sprayed Aluminum (TSA) with Cathodic Protection as Corrosion Protection for Steel in Natural Seawater : Characterization of Properties on TSA and Calcareous Deposit

    Egtvedt, Solveig

    2011-01-01

    Cathodic protection is an effective corrosion protection for structures submerged in seawater. In addition to applying the current need to lower the metal below the protection potential, a resulting increase in interfacial pH leads to precipitation of calcareous deposit. This deposited layer act as a barrier against oxygen diffusion on the surface, hence lowering the current demand of the structure. However, this layer will also hinder the thermal conductivity, and is therefore unwanted at th...

  1. Microbial corrosion and cracking in steel. A concept for evaluation of hydrogen-assisted stress corrosion cracking in cathodically protected high-pressure gas transmission pipelines

    Vendelbo Nielsen, L.

    1998-08-01

    An effort has been undertaken in order to develop a concept for evaluation of the risk of hydrogen-assisted cracking in cathodically protected gas transmission pipelines. The effort was divided into the following subtasks: A. Establish a correlation between the fracture mechanical properties of high-strength pipeline steel and the concentration of hydrogen present in the steel. B. Determine the degree hydrogen absorption by cathodically protected steel exposed in natural soil sediment, which include activity of sulphate-reducing bacteria (SRB). C. Compare the above points with fracture mechanical considerations on the level of stress intensity actually present in pipelines during normal operational conditions. The results were used for a discussion - based on well established fracture mechanical relations - on which set of conditions (CP-level and operating pipeline pressure) could give crack propagation. This resulted in threshold curves that can be used for assessment of the risk of hydrogen-assisted cracking as a function of operating pressure and hydrogen content - having the flaw size as discrete parameter. The results are to be used mainly on a conceptual basis, but it was indicated that the requirements for crack propagation include an overprotective CP-condition, a severe sulphate-reducing environment, as well as a large flaw (8 mm or a leak in the present case). A 1 mm flaw (which may be the maximum realistic flaw size) is believed to be unable to provoke crack propagation in this steel. (EG) EFP-95. 16 refs.

  2. Effect of cathodic protection on the state of steel reinforcement

    Damage of reinforced concrete structures is mainly caused by chloride or carbonation induced corrosion of steel. Cathodic protection is a very effective measure for corrosion control of steel in concrete, especially in chloride contaminated concrete. In this paper, effect of cathodic protection on the state of steel reinforcement is presented. Cathodic polarization of reinforcements in concrete was done under different submerged conditions. Cyclic potentiodynamic tests were used to determine the effect of cathodic protection on the behavior of the steel. Pitting appeared on the non-protected steel, but was not observed on the cathodically protected steel. microscopic photographs show that a close film exists on the protected steel, while the non-protected steel's film is loose. Investigated results have proved the effect of cathodic protection in restoring or strengthening passive film on the steel reinforcement

  3. Liquid Coatings for Reducing Corrosion of Steel in Concrete

    MacDowell, Louis G.; Curran, Joseph

    2003-01-01

    Inorganic coating materials are being developed to slow or stop corrosion of reinforcing steel members inside concrete structures. It is much simpler and easier to use these coating materials than it is to use conventional corrosion-inhibiting systems based on impressed electric currents. Unlike impressed electrical corrosion-inhibiting systems, these coatings do not require continuous consumption of electrical power and maintenance of power-supply equipment. Whereas some conventional systems involve the use of expensive arc-spray equipment to apply the metallic zinc used as the sacrificial anode material, the developmental coatings can be applied by use of ordinary paint sprayers. A coating material of the type under development is formulated as a liquid containing blended metallic particles and/or moisture-attracting compounds. The liquid mixture is sprayed onto a concrete structure. Experiments have shown that even though such a coat resides on the exterior surface, it generates a protective galvanic current that flows to the interior reinforcing steel members. By effectively transferring the corrosion process from the steel reinforcement to the exterior coating, the protective current slows or stops corrosion of the embedded steel. Specific formulations have been found to meet depolarization criteria of the National Association of Corrosion Engineers (NACE) for complete protection of steel reinforcing bars ("rebar") embedded in concrete.

  4. Corrosion of plasma nitrided austenitic stainless steels

    The corrosion behaviour of plasma nitrided austenitic stainless steel grades AISI 304, 316 and 321 was studied at various temperatures. Certain plasma nitriding cycles included a post-oxidation treatment. The corrosion rates were measured using linear polarisation technique. Results showed that corrosion rate increased with the plasma nitriding temperature. Minimum deterioration occurred at 653K. (author). 2 tabs., 4 figs., 10 refs

  5. Corrosion protection with eco-friendly inhibitors

    Corrosion occurs as a result of the interaction of a metal with its environment. The extent of corrosion depends on the type of metal, the existing conditions in the environment and the type of aggressive ions present in the medium. For example, CO3−2 and NO−3 produce an insoluble deposit on the surface of iron, resulting in the isolation of metal and consequent decrease of corrosion. On the other hand, halide ions are adsorbed selectively on the metal surface and prevent formation of the oxide phase on the metal surface, resulting in continuous corrosion. Iron, aluminum and their alloys are widely used, both domestically and industrially. Linear alkylbenzene and linear alkylbenzene sulfonate are commonly used as detergents. They have also been found together in waste water. It is claimed that these chemicals act as inhibitors for stainless steel and aluminum. Release of toxic gases as a result of corrosion in pipelines may lead in certain cases to air pollution and possible health hazards. Therefore, there are two ways to look at the relationship between corrosion and pollution: (i) corrosion of metals and alloys due to environmental pollution and (ii) environmental pollution as a result of corrosion protection. This paper encompasses the two scenarios and possible remedies for various cases, using 'green' inhibitors obtained either from plant extracts or from pharmaceutical compounds. In the present study, the effect of piperacillin sodium as a corrosion inhibitor for mild steel was investigated using a weight-loss method as well as a three-electrode dc electrochemical technique. It was found that the corrosion rate decreased as the concentration of the inhibitor increased up to 9×10−4 M; 93% efficiency was exhibited at this concentration. (review)

  6. Corrosion protection with eco-friendly inhibitors

    Shahid, Muhammad

    2011-12-01

    Corrosion occurs as a result of the interaction of a metal with its environment. The extent of corrosion depends on the type of metal, the existing conditions in the environment and the type of aggressive ions present in the medium. For example, CO3‑2 and NO‑3 produce an insoluble deposit on the surface of iron, resulting in the isolation of metal and consequent decrease of corrosion. On the other hand, halide ions are adsorbed selectively on the metal surface and prevent formation of the oxide phase on the metal surface, resulting in continuous corrosion. Iron, aluminum and their alloys are widely used, both domestically and industrially. Linear alkylbenzene and linear alkylbenzene sulfonate are commonly used as detergents. They have also been found together in waste water. It is claimed that these chemicals act as inhibitors for stainless steel and aluminum. Release of toxic gases as a result of corrosion in pipelines may lead in certain cases to air pollution and possible health hazards. Therefore, there are two ways to look at the relationship between corrosion and pollution: (i) corrosion of metals and alloys due to environmental pollution and (ii) environmental pollution as a result of corrosion protection. This paper encompasses the two scenarios and possible remedies for various cases, using 'green' inhibitors obtained either from plant extracts or from pharmaceutical compounds. In the present study, the effect of piperacillin sodium as a corrosion inhibitor for mild steel was investigated using a weight-loss method as well as a three-electrode dc electrochemical technique. It was found that the corrosion rate decreased as the concentration of the inhibitor increased up to 9×10‑4 M 93% efficiency was exhibited at this concentration.

  7. Microbial corrosion inhibition of mild steel in salty water environment

    The use of antimicrobial corrosion inhibitor is increasingly being curtailed by recent corrosion restrictions. This paper represents the results of the study of new biocide, antimicrobial corrosion inhibitor named 8-hydroxy-N'-(2-(quinolin-8-yloxy)acetyl)quinoline-5-sulfonohydrazide (HQS) was used to inhibit corrosion causing sulphate reducing bacteria (SRB). The effects of the inhibitor on mild steel dissolution in salty water environment were studied through weight loss measurements, electrochemical and microorganism tests. The results obtained from this study show that, the new inhibitor can decrease corrosion and microbial growth under the conditions tested. The mass loss for the protected mild steel coupons shows lower corrosion rate compared to the unprotected once. Cyclic polarization test reveals that, the biocide minimizes the pitting area (hysteresis). The nature of protective film formed on mild steel was studied by scanning electron microscopy (SEM). SEM images revealed that, the corrosion inhibition by the HQS on the mild steel surface significantly improved in the presence of biocide

  8. Microbial corrosion inhibition of mild steel in salty water environment

    El-Shamy, A.M. [Electrochemistry and Corrosion Lab., Department of Physical Chemistry, National Research Centre, Dokki, 12622 Cairo (Egypt); Soror, T.Y. [Chemistry Department, Faculty of Science, Cairo University, Cairo (Egypt); El-Dahan, H.A. [Electrochemistry and Corrosion Lab., Department of Physical Chemistry, National Research Centre, Dokki, 12622 Cairo (Egypt)], E-mail: hosnieldahan@yahoo.com; Ghazy, E.A. [Microbial Biotechnology Department, National Research Centre, Dokki, 12622 Cairo (Egypt); Eweas, A.F. [Medicinal Chemistry Department, National Research Centre, Dokki, 12622, Cairo (Egypt)

    2009-03-15

    The use of antimicrobial corrosion inhibitor is increasingly being curtailed by recent corrosion restrictions. This paper represents the results of the study of new biocide, antimicrobial corrosion inhibitor named 8-hydroxy-N'-(2-(quinolin-8-yloxy)acetyl)quinoline-5-sulfonohydrazide (HQS) was used to inhibit corrosion causing sulphate reducing bacteria (SRB). The effects of the inhibitor on mild steel dissolution in salty water environment were studied through weight loss measurements, electrochemical and microorganism tests. The results obtained from this study show that, the new inhibitor can decrease corrosion and microbial growth under the conditions tested. The mass loss for the protected mild steel coupons shows lower corrosion rate compared to the unprotected once. Cyclic polarization test reveals that, the biocide minimizes the pitting area (hysteresis). The nature of protective film formed on mild steel was studied by scanning electron microscopy (SEM). SEM images revealed that, the corrosion inhibition by the HQS on the mild steel surface significantly improved in the presence of biocide.

  9. METHOD FOR ARRANGEMENT OF HIGH-STRENGTH CORROSION-RESISTANT FOR EFFICIENT PROTECTION OF STEEL PIPELINES OPERATED IN THE EXTREME NORTH

    I. S. Surovtsev

    2011-11-01

    Full Text Available Problem statement. At present, the problem of main pipeline protection from corrosion is extremelyimportant. Principal gas-transport routes have the biggest length in the North areas whereclimatic and geotechnical conditions are adverse. Scientists of Voronezh State University of Architectureand Civil Engineering have developed new material, rubber concrete. This material isbased on liquid oligodienes and has unique set of operational characteristics. The material can beefficiently used as insulation material for metal pipe in the conditions of the Extreme North.Results. The method for arrangement of protective coating of metal pipe is developed on the basisof rubber concrete. The method is patented. Laboratory device which allows one to perform structuresformation of rubber mastic on the surface of metal pipe is constructed. Physicomechanicalproperties of rubber concrete as insulation material for steel pipes are determined.Conclusions. The results of experiments allow us to draw a conclusion on the expediency of the useof rubber concrete as a protection coating material for steel pipes operated in the Extreme North.

  10. Complex Protection of Vertical Stainless Steel Tanks

    Fakhrislamov Radik Zakievich

    2014-01-01

    The authors consider the problem of fail-safe oil and oil products storage in stainless steel tanks and present the patented tank inner side protection technology. The latter provides process, ecological and fire safety and reducing soil evaporation of oil products, which is a specific problem. The above-mentioned technology includes corrosion protection and heat insulation protection providing increase of cover durability and RVS service life in general. The offered technological protection ...

  11. General corrosion of carbon steels in high temperature water

    This short paper seeks to provide a summary of the main knowledge about the general corrosion of carbon steels in high temperature water. In pure water or slightly alkaline deaerated water, steels develop a protective coating of magnetite in a double layer (Potter and Mann oxide) or a single layer (Bloom oxide). The morphology of the oxide layer and the kinetics of corrosion depend on the test parameters controlling the solubility of iron. The parameters exercising the greatest influence are partial hydrogen pressure and mass transfer: hydrogen favours the solubilization of the magnetite; the entrainment of the dissolved iron prevents a redeposition of magnetite on the surface of the steel. Cubic or parabolic in static conditions, the kinetics of corrosion tends to be linear in dynamic conditions. In dynamic operation, corrosion is at least one order of magnitude lower in water with a pH of 10 than in pure water with a pH of 7. The activation energy of corrosion is 130 kJ/mol (31 kcal/mol). This results in the doubling of corrosion at around 300 deg C for a temperature increase of 15 deg C. Present in small quantities (100-200 ppb), oxygen decreases general corrosion but increases the risk of pitting corrosion - even for a low chloride content - and stress corrosion cracking or corrosion-fatigue. The steel composition has probably an influence on the kinetics of corrosion in dynamic conditions; further work would be required to clarify the effect of some residual elements. (author). 31 refs., 9 figs., 2 tabs

  12. The Corrosion of High Performance Steel in Adverse Environments

    The corrosion products that have formed on weathering steel bridges exposed to different weather conditions in the United States have been evaluated. They have been analyzed by spectroscopic techniques to determine the relationship between protective and non-protective rust coatings, and their relationship to the exposure conditions. Bridges constructed recently using High Performance Steel, as well as older bridges built with Type A588B weathering steel, were evaluated for corrosion performance of the rust coatings. In locations where the steel is subjected to regular wet-dry cycling, where the surface is wet for less than about 20% of the time, a protective patina starts to form after a few months exposure, and continues to an adherent, impervious coating after a decade. The protective patina is characterized by the formation of only goethite and lepidocrocite. The goethite makes up about 80% of the rust, and itself consists of a nanophase component, 40%, or infrequent drying cycles (regions close to waterways, fog or having high humidity), the weathering steel forms a rust coating that consists of a large amount of maghemite, and goethite that contains very little of the nanophase component. The rust coating ex-foliates from the steel and is not protective. Under exposure conditions in which chlorides are deposited onto the weathering steel surface (marine or de-icing salt locations), the protective patina also does not form. Instead, the rust coating consists of a large fraction of akaganeite that forms at the expense of the lepidocrocite and nanophase goethite. The bridges exposed to high chloride concentrations, 1.5 wt%, and therefore having no protective patina, have corrosion rates measured to be 6 times larger than expected for weathering steel with the protective patina

  13. Internal corrosion of carbon steel piping in hot aquifers service

    Simičić Miloš V.

    2011-01-01

    Full Text Available Internal corrosion of carbon steel pipelines is a major problem encountered in water service. In terms of prediction of the remaining lifetime for water pipelines based on the corrosion allowance, the three main approaches are corrosion modelling, corrosion inhibitor availability, and corrosion monitoring. In this study we used two theoretical corrosion models, CASSANDRA and NORSOK M-506 of quite different origin in order to predict uniform corrosivity of hot aquifers in eight different pipelines. Because of the varying calculation criteria for the different models, these can give very different corrosion rate predictions for the same data input. This is especially true under conditions where the formation of protective films may occur, such as at elevated temperatures. The evaluation of models was conducted by comparison using weight-loss coupons and three corrosion inhibitors were obtained from commercial suppliers. The tests were performed during the 60-day period. Even though inhibitors’ efficiencies of 98% had been achieved in laboratory testing, inhibitors’ availabilities of 85% have been used due to logistics problems and other issues. The results, given in mmpy, i.e. millimeter per year, are very consistent with NORSOK M-506 prediction. This is presumably because the model considers the effect of the formation of a passive iron carbonate film at temperatures above 80 °C and significant reduction in corrosion rate. Corrosion inhibitor A showed a better performance than inhibitors B and C in all cases but the target corrosion rates of less than 0.1 mmpy were achieved for all inhibitors. The chemical type of corrosion inhibitor A is based on quaternary amines mixed with methanol, isopropyl alcohol, xylene and ethylbenzene. Based on the obtained results the carbon steel lifetime of 30 years, provided proper inhibitors are present and 3mm corrosion allowance, can be achieved for hot aquifers service with presented water compositions.

  14. Corrosion behavior of sensitized duplex stainless steel.

    Torres, F J; Panyayong, W; Rogers, W; Velasquez-Plata, D; Oshida, Y; Moore, B K

    1998-01-01

    The present work investigates the corrosion behavior of 2205 duplex stainless steel in 0.9% NaCl solution after various heat-treatments, and compares it to that of 316L austenitic stainless steel. Both stainless steels were heat-treated at 500, 650, and 800 degrees C in air for 1 h, followed by furnace cooling. Each heat-treated sample was examined for their microstructures and Vickers micro-hardness, and subjected to the X-ray diffraction for the phase identification. Using potentiostatic polarization method, each heat-treated sample was corrosion-tested in 37 degrees C 0.9% NaCl solution to estimate its corrosion rate. It was found that simulated sensitization showed an adverse influence on both steels, indicating that corrosion rates increased by increasing the sensitization temperatures. PMID:9713683

  15. Corrosion-protective coatings from electrically conducting polymers

    Thompson, Karen Gebert; Bryan, Coleman J.; Benicewicz, Brian C.; Wrobleski, Debra A.

    1991-01-01

    In a joint effort between NASA Kennedy and LANL, electrically conductive polymer coatings were developed as corrosion protective coatings for metal surfaces. At NASA Kennedy, the launch environment consist of marine, severe solar, and intermittent high acid and/or elevated temperature conditions. Electrically conductive polymer coatings were developed which impart corrosion resistance to mild steel when exposed to saline and acidic environments. Such coatings also seem to promote corrosion resistance in areas of mild steel where scratches exist in the protective coating. Such coatings appear promising for many commercial applications.

  16. Corrosion of an austenite and ferrite stainless steel weld

    BRANIMIR N. GRGUR

    2011-07-01

    Full Text Available Dissimilar metal connections are prone to frequent failures. These failures are attributed to the difference in the mechanical properties across the weld, the coefficients of thermal expansion of the two types of steels and the resulting creep at the interface. For the weld analyzed in this research, it was shown that corrosion measurements can be used for a proper evaluation of the quality of weld material and for the prediction of whether or not the material, after the applied welding process, can be in service without failures. It was found that the corrosion of the weld analyzed in this research resulted from the simultaneous activity of different types of corrosion. In this study, electrochemical techniques including polarization and metallographic analysis were used to analyze the corrosion of a weld material of ferrite and austenitic stainless steels. Based on surface, chemical and electrochemical analyses, it was concluded that corrosion occurrence was the result of the simultaneous activity of contact corrosion (ferrite and austenitic material conjuction, stress corrosion (originating from deformed ferrite structure and inter-granular corrosion (due to chromium carbide precipitation. The value of corrosion potential of –0.53 V shows that this weld, after the thermal treatment, is not able to repassivate a protective oxide film.

  17. Corrosion Properties of Laser Welded Stainless Steel

    Weldingh, Jakob; Olsen, Flemmming Ove

    1997-01-01

    In this paper the corrosion properties of laser welded AISI 316L stainless steel are examined. A number of different welds has been performed to test the influence of the weld parameters of the resulting corrosion properties. It has been chosen to use the potential independent critical pitting...

  18. Corrosion of austenitic steel in sodium loops

    The possibility of predicting corrosion effects for austenitic steel exposed to liquid sodium with an analytical diffusion model is presented. The analytically predicated corrosion effects are compared with experimental measurements of corrosion effects achieved in an accurately controlled sodium loop. The diffusion model is described with figures showing disc sample weight loss and sodium flow guidance tube chromium and nickel profiles. Finally, the concentration profile in the fuel rod wall (diffusion model) is presented for iron, chromium and nickel

  19. Corrosion Behavior of Carbon Steels in CCTS Environment

    Cabrini, M; S. Lorenzi; T. Pastore

    2016-01-01

    The paper reports the results of an experimental work on the effect of steel microstructures on morphology and protectiveness of the corrosion scale formed in water saturated by supercritical CO2. Two HSLA steels were tested. The microstructures were modified by means of different heat treatments. Weight loss was measured after exposure at CO2 partial pressure of 80 bar and 60°C temperature. The morphology of the scale was analyzed by means of scanning electron microscope (SEM) energy-dispers...

  20. Effect of CO2 on Atmospheric Corrosion of UNS G10190 Steel under Thin Electrolyte Film

    2000-01-01

    The atmospheric corrosion of UNS G10190 steel under a thin electrolyte film in the atmosphere polluted by CO2 has been studied in the lab using an atmospheric corrosion monitor(ACM) in combination with XRD and SEM observations of the surface of steel. The ACM study indicated that the corrosion rate of the steel increased with increasing carbon dioxide concentration. The XRD and SEM observations showed that no carbonate was found in the corrosion product on the steel surface. The corrosion product consisted of two layers, i. e., inner and outer layer. From the experimental results, it was concluded that CO2 played an enhancing role in the atmospheric corrosion of UNS G10190 steel. The film of the corrosion product showed slight protection.

  1. Atmospheric corrosion of mild steel. Pt. I. Rural and urban atmospheres

    This paper summarizes the results obtained in the MICAT project for mild steel specimens exposed for 1 to 4 years in 22 rural and urban atmospheres in the Ibero-American region. Test site characterization and chemical and morphological determination of the steel corrosion product layers (SCPLs) contributed to understanding the corrosion phenomena involved. It was observed how some climatological factors could affect steel corrosion rates and SCPL properties. Although the studied atmospheres were classified into different ISO groups, steel corrosion rates did not differ significantly between them. The only common characteristic of these atmospheres was an increase in SCPLs protectiveness with exposure time. (orig.)

  2. Corrosion of Steel in Concrete, Part I – Mechanisms

    Küter, André; Møller, Per; Geiker, Mette Rica

    2006-01-01

    prematurely. Reinforcement corrosion is identified to be the foremost cause of deterioration. Steel in concrete is normally protected by a passive layer due the high alkalinity of the concrete pore solution; corrosion is initiated by neutralization through atmospheric carbon dioxide and by ingress of......Throughout the world reinforced concrete is the most widely used construction material for buildings and civil engineering structures. Most reinforced concrete structures have performed satisfactory over many decades, but there still is an unacceptable large number of structures that deteriorate...... depassivation ions, especially chloride ions. The background and consequences of deterioration of reinforced concrete structures caused by steel corrosion are summarized. Selected corrosion mechanisms postulated in the literature are briefly discussed and related to observations. The key factors controlling...

  3. Corrosion behavior of carbon steel in wet Na-bentonite medium

    Corrosion behaviors of carbon steel in wet Na-bentonite medium were studied. Corrosion rate of carbon steel in wet bentonite was measured to be 20 μm/yr at 25 deg C using the AC impedance technique. This value is agreed with that obtained by weight loss at 40 deg C for 1 year. The effect of bicarbonate ion on the corrosion of carbon steel in wet bentonite was also evaluated. The carbon steels in wet bentonite having 0.001, 0.01, and 0.1 M concentration of bicarbonate ion gave corrosion rates of 20, 8, and 0.2 μm/yr, respectively. Corrosion potentials of specimens were also measured and compared with the AC impedance results. Both results indicated that bicarbonate ion could effectively reduce the corrosion rate of carbon steels in bentonite due to the formation of protective layer on the carbon steel. (author)

  4. Development of novel protective high temperature coatings on heat exchanger steels and their corrosion resistance in simulated coal firing environment; Developpement de revetements pour les aciers d'echangeurs thermiques et amelioration de leur resistance a la corrosion en environnement simulant les fumees de combustion et de charbon

    Rohr, V.

    2005-10-15

    Improving the efficiencies of thermal power plants requires an increase of the operating temperatures and thus of the corrosion resistance of heat exchanger materials. Therefore, the present study aimed at developing protective coatings using the pack cementation process. Two types of heat exchanger steels were investigated: a 17% Cr-13% Ni austenitic steel and three ferritic-martensitic steels with 9 (P91 and P92) and 12% Cr (HCM12A). The austenitic steel was successfully aluminized at 950 C. For the ferritic-martensitic steels, the pack cementation temperature was decreased down to 650 C, in order to maintain their initial microstructure. Two types of aluminides, made of Fe{sub 2}Al{sub 5} and FeAl, were developed. A mechanism of the coating formation at low temperature is proposed. Furthermore, combining the pack cementation with the conventional heat treatment of P91 allowed to take benefit of higher temperatures for the deposition of a two-step Cr+Al coating. The corrosion resistance of coated and uncoated steels is compared in simulated coal firing environment for durations up to 2000 h between 650 and 700 C. It is shown that the coatings offer a significant corrosion protection and, thus, an increase of the component lifetime. Finally, the performance of coated 9-12% Cr steels is no longer limited by corrosion but by interdiffusion between the coating and the substrate. (author)

  5. Superclean steel development: Stress corrosion cracking characteristics

    1990-07-01

    Stress corrosion tests (SCC initiation and propagation) were carried out on a high purity version of the 3.5% NiCrMoV low pressure rotor steel in comparison to similar steels of conventional cleanness. In the constant load tests in 30% sodium hydroxide solution the clean steel showed longer times to crack initiation than the conventional steels with comparable strength levels. The amount of scatter makes it difficult to quantify the improvement, which lay at or above 5% in stress level. Neither in pure water (aerated and deaerated) nor in a concentrated caustic solution were differences in the stress corrosion crack velocities detected. Neither the clean steel nor the conventional steel tested in this programme showed any increase in SCC susceptibility after aging at 350 or 450{degree}C for 10,000 hours. 19 refs., 17 figs., 3 tabs.

  6. Marine atmospheric corrosion of carbon steels

    Basic research on marine atmospheric corrosion of carbon steels is a relatively young scientific field and there continue to be great gaps in this area of knowledge. The presence of akaganeite in the corrosion products that form on steel when it is exposed to marine atmospheres leads to a notable increase in the corrosion rate. This work addresses the following issues: (a) environmental conditions necessary for akaganeite formation; (b) characterisation of akaganeite in the corrosion products formed; (c) corrosion mechanisms of carbon steel in marine atmospheres; (d) exfoliation of rust layers formed in highly aggressive marine atmospheres; (e) long-term corrosion rate prediction; and (f) behaviour of weathering steels. Field research has been carried out at Cabo Vilano wind farm (Camarinas, Galicia) in a wide range of atmospheric salinities and laboratory work involving the use of conventional atmospheric corrosion techniques and near-surface and bulk sensitive analytical techniques: scanning electron microscopy (SEM)/energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Mossbauer spectroscopy and SEM/μRaman spectroscopy. (Author)

  7. Marine atmospheric corrosion of carbon steels

    Morcillo, M.; Alcantara, J.; Diaz, I.; Chico, B.; Simancas, J.; Fuente, D. de la

    2015-07-01

    Basic research on marine atmospheric corrosion of carbon steels is a relatively young scientific field and there continue to be great gaps in this area of knowledge. The presence of akaganeite in the corrosion products that form on steel when it is exposed to marine atmospheres leads to a notable increase in the corrosion rate. This work addresses the following issues: (a) environmental conditions necessary for akaganeite formation; (b) characterisation of akaganeite in the corrosion products formed; (c) corrosion mechanisms of carbon steel in marine atmospheres; (d) exfoliation of rust layers formed in highly aggressive marine atmospheres; (e) long-term corrosion rate prediction; and (f) behaviour of weathering steels. Field research has been carried out at Cabo Vilano wind farm (Camarinas, Galicia) in a wide range of atmospheric salinities and laboratory work involving the use of conventional atmospheric corrosion techniques and near-surface and bulk sensitive analytical techniques: scanning electron microscopy (SEM)/energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Mossbauer spectroscopy and SEM/μRaman spectroscopy. (Author)

  8. Corrosion behavior of duplex polyaniline/epoxy coating on mild steel in 3% NaCl

    Gvozdenović Milica M.; Grgur Branimir N.; Kačarević-Popović Zorica M.; Mišković-Stanković Vesna B.

    2005-01-01

    The corrosion behavior and thermal stability of epoxy coatings electrodeposited on mild steel and on mild steel with electrochemically deposited polyaniline (PANI) film were investigated by electrochemical impedance spectroscopy (EIS) and thermo gravimetric analysis (TGA). The aim of the paper was to present new findings on the corrosion protection of mild steel by a duplex PANI/-epoxy coating in 3% NaCI solution and to determine the effect of thin PANI film on the protective properties of th...

  9. Laboratory study of reinforcement protection with corrosion inhibitors

    Concrete is a durable material and its performance as part of the containment function in NPPs has been good. However, experience shows that degradation of the reinforced concrete structures caused by the corrosion of the reinforcing steel represents more than 80% of all damages in the world. Much effort has been made to develop a corrosion inhibition process to prolong the life of existing structures and minimize corrosion damages in new structures. Migrating Corrosion Inhibitor technology was developed to protect the embedded steel rebar/concrete structure. These inhibitors can be incorporated as an admixture or can be surface impregnated on existing concrete structures. The effectiveness of two inhibitors (ethanolamine and diethanolamine) mixed in the reinforced concrete was evaluated by gravimetric measurements. The corrosion behavior of the steel rebar and the inhibiting effects of the amino alcohol chemistry in an aggressive environment were monitored using electrochemical measurements and scanning electron microscopy (SEM) investigations. (authors)

  10. Microbially influenced corrosion of carbon steels

    White, D.C.; Jack, R.F.; Dowling, N.J.E.; Franklin, M.J.; Nivens, D.E.; Brooks, S.; Mittelman, M.W.; Vass, A.A. (Tennessee Univ., Knoxville, TN (USA). Inst. for Applied Microbiology); Isaacs, H.S. (Brookhaven National Lab., Upton, NY (USA))

    1990-01-01

    Microbially influenced corrosion of pipeline steels is an economically important problem. Microbes form tubercles which block fluid flow and can facilitate localized corrosion leading to through-wall penetrations. Microbes of diverse physiological types and metabolic potentialities have been recovered from fresh tubercles or under-deposit corrosion and have been characterized. In tests utilizing sterilizable flow-through systems containing pipeline steel coupons, corrosion rates determined by nondestructive electrochemical means have indicated that increasing the number of physiological types of microbes inoculated into the system generally increased the severity of the microbially influenced corrosion (MIC). This study reports the MIC of monocultures and combinations of monocultures in an aerobic fresh water system with low sulfate and an anaerobic saline system. In both the aerobic and anaerobic systems, the combination of microbes induced greater MIC responses than the monocultures. In tests involving a combination of microbes in both systems in which one member was a sulfate-reducing bacteria (SRB), the corrosion mechanism was different for the control and the monocultures. This difference was indicated by the phase shift in the electrochemical impedance spectra (EIS). The localization of corrosion, that in many cases is the hallmark of MIC, may be initiated by the inhomogeneities of supposedly smooth metal surfaces. The scanning vibrating electrode technique (SVET) demonstrated non-uniform current densities over carbon steel electrodes polished to a 600 grit finish suggesting pitting and repassivation of pits in sterile medium.

  11. Crevice Corrosion of 321 Stainless Steel in Sodium Chloride Solutions

    Electrochemical techniques have been applied to study the crevice corrosion behaviour of stabilized 321 stainless steel in both 0.5, 1 and 2 M sodium chloride solutions at 25 and 80 degree . This type of stainless steel enjoys a good corrosion resistance especially in the heat affected zone (Haz) of welds. In this investigation the crevice corrosion of 321 stainless steel was studied in both bulk solution environments as well as in chloride solutions simulating those formed inside crevices. A metal-to-nonmetal crevice assembly, in which disc type specimens were faced to a PTFE crevice former, is used for bulk solution tests. Crevice-free specimens of solutions formed inside crevices (known as the critical crevice solutions, CCS). Cyclic potentiodynamic technique was used in evaluating the electrochemical corrosion performance of the alloy in bulk (0.5 and 1 M Nacl) environment. This revealed that both chloride ion concentration and temperature have a marked effect on the electrochemical parameters generally used for the evaluation of the crevice corrosion susceptibility. This included the corrosion potential. E corr. The passivity breakdown potential, Eb, and the protection potential, E p

  12. Corrosion behavior of novel 3%Cr pipeline steel in CO2 Top-of-Line Corrosion environment

    Highlights: ► CO2 Top-of-Line Corrosion environment in wet gas pipelines was simulated. ► Compared with X70, the resistance to CO2 TLC of novel 3%Cr pipeline steel is better. ► The effect of Cr enrichment in the corrosion scale on CO2 TLC is confirmed. -- Abstract: CO2 Top-of-Line Corrosion (TLC) of carbon steel pipelines is a serious problem for wet gas transportation. We have studied the corrosion behavior of novel 3%Cr (3Cr) pipeline steel and conventional carbon steel (X70) in the simulated CO2 TLC environment. The composition and morphology of the corrosion scale are characterized by X-ray diffraction, energy dispersive X-ray spectroscopy and scanning electron microscopy analyses. The results indicate that 3Cr pipeline steel shows superior resistance to CO2 TLC, exhibiting uniform corrosion with duplex corrosion layer, while X70 suffers severe localized corrosion. It was suggested that the inner Cr enriched layer enhanced the protective ability of the scale to steel substrate and improved the resistance to localized corrosion in CO2 TLC environment.

  13. POLYETHERSULFONE COATING FOR MITIGATING CORROSION OF STEEL IN GEOTHERMAL ENVIRONMENT.

    SUGAMA, T.

    2005-06-01

    Emphasis was directed toward evaluating the usefulness of a polyethersulfone (PES)-dissolved N-methyl pyrrolidone (NMP) solvent precursor as a low-temperature film-forming anti-corrosion coating for carbon steel in simulated geothermal environments at brine temperatures up to 300 C. A {approx} 75 {micro}m thick PES coating performed well in protecting the steel against corrosion in brine at 200 C. However, at {>=} 250 C, the PES underwent severe hydrothermal oxidation that caused the cleavage of sulfone- and ether-linkages, and the opening of phenyl rings. These, in turn, led to sulfone {yields} benzosulfonic acid and ether {yields} benzophenol-type oxidation derivative transformations, and the formation of carbonyl-attached open rings, thereby resulting in the incorporation of the functional groups, hydroxyl and carbonyl, into the coating. The presence of these functional groups raised concerns about the diminutions in water-shedding and water-repellent properties that are important properties of the anti-corrosion coatings; such changes were reflected in an enhancement of the magnitude of susceptibility of the coatings surfaces to moisture. Consequently, the disintegration of the PES structure by hydrothermal oxidation was detrimental to the maximum efficacy of the coating in protecting the steel against corrosion, allowing the corrosive electrolytes to infiltrate easily through it.

  14. Complex Protection of Vertical Stainless Steel Tanks

    Fakhrislamov Radik Zakievich

    2014-03-01

    Full Text Available The authors consider the problem of fail-safe oil and oil products storage in stainless steel tanks and present the patented tank inner side protection technology. The latter provides process, ecological and fire safety and reducing soil evaporation of oil products, which is a specific problem. The above-mentioned technology includes corrosion protection and heat insulation protection providing increase of cover durability and RVS service life in general. The offered technological protection scheme is a collaboration of the author, Steel Paint GmbH firm and JSC “Koksokhimmontazhproyekt”. PU foam unicomponent materials of Steel Paint GmbH firm provide the protection of tank inner side and cover.

  15. A Study on Atmospheric Corrosion of 304 Stainless Steel in a Simulated Marine Atmosphere

    Lv, Wangyan; Pan, Chen; Su, Wei; Wang, Zhenyao; Liu, Shinian; Wang, Chuan

    2015-07-01

    The atmospheric corrosion behavior of 304 stainless steel in a simulated marine atmosphere has been investigated using scanning electron microscope, optical microscope, x-ray photoelectron spectroscopy (XPS), and electrochemical measurements. The experimental results indicate that the main corrosion type of 304 stainless steel in a simulated marine atmosphere is pitting corrosion and the initiation of pits is associated with the dissolution of MnS inclusion. The maximum pit depth of 304 stainless steel increased in linear relationship with the extension of corrosion time. XPS results reveal that the corrosion products possess more hydroxide, and the ratio of [Cr]/{[Cr]+[Fe]} in the corrosion products gradually increases with the increasing time. The protective ability of corrosion products formed on 304 stainless steel has also been discussed.

  16. Research on atmospheric corrosion of steel using synchrotron radiation

    Correlation between local structure around Cr in the protective rust layer on weathering steel and protective performance of the rust layer is presented as an example of corrosion research using synchrotron radiation which has recently been applied in various research fields as a useful tool. In addition, in situ observation of initial process of rust formation on steel is also mentioned. It was pointed out by considering the X-ray absorption fine structure spectra that the nanostructure of the protective rust layer on weathering steel primarily comprises of small Cr-goethite crystals containing surface adsorbed and/or intergranular CrOx3-2X complex anions. This CrOx3-2X explains the protective performance of the rust layer originated by dense aggregation of fine crystals with cation selectivity of the Cr-goethite. It is very advantageous to employ white X-rays for in situ observation of rusting process of a carbon steel covered with electrolyte thin films because rust structure might change very quickly. This in situ observation revealed the effect of ion species on the change in rust phase during wet/dry repeating. It can be said that application of synchrotron radiation on corrosion research is so useful to understand the nanostructure of surface oxides which closely relate to corrosion behavior of metals and alloys. (author)

  17. Corrosion of steel tendons used in prestressed concrete pressure vessels

    The purpose of this investigation was to determine the corrosion behavior of a high strength steel (ASTM A416-74 grade 270), typical of those used as tensioning tendons in prestressed concrete pressure vessels, in several corrosive environments and to demonstrate the protection afforded by coating the steel with either of two commercial petroleum-base greases or Portland Cement grout. In addition, the few reported incidents of prestressing steel failures in concrete pressure vessels used for containment of nuclear reactors are reviewed. The susceptibility of the steel to stress corrosion cracking and hydrogen embrittlement and its general corrosion rate were determined in several salt solutions. Wires coated with the greases and grout were soaked for long periods in the same solutions and changes in their mechanical properties were subsequently determined. All three coatings appeared to give essentially complete protection but small flaws in the grease coatings were detrimental; flaws or cracks less than 1 mm wide in the grout were without effect

  18. Corrosion of steel tendons used in prestressed concrete pressure vessels

    The corrosion behavior of a high-strength steel [Specifications for Uncoated Seven-Wire-Stress-Relieved Strand for Prestressed Concrete (ASTM A 416-74, Grade 270)], typical of those used as tensioning tendons in prestressed concrete pressure vessels was measured in several corrosive environments. The protection obtained by coating the steel with two commercial petroleum-base greases or with Portland cement grout was evaluated. The few reported incidents of prestressing steel failures in concrete pressure vessels used for containment of nuclear reactors were reviewed. The susceptibility of the steel to stress corrosion cracking and hydrogen embrittlement and its general corrosion rate were determined in several salt solutions. Wires coated with the greases and grout were soaked for long periods in the same solutions and changes in their mechanical properties were subsequently determined. All three coatings appeared to give essentially complete protection; however, flaws in the grease coatings could be detrimental, and flaws or cracks less than 1-mm-wide (0.04 in.) in the grout were without effect

  19. Treatment Prevents Corrosion in Steel and Concrete Structures

    2007-01-01

    In the mid-1990s, to protect rebar from corrosion, NASA developed an electromigration technique that sends corrosion-inhibiting ions into rebar to prevent rust, corrosion, and separation from the surrounding concrete. Kennedy Space Center worked with Surtreat Holding LLC, of Pittsburgh, Pennsylvania, a company that had developed a chemical option to fight structural corrosion, combining Surtreat's TPS-II anti-corrosive solution and electromigration. Kennedy's materials scientists reviewed the applicability of the chemical treatment to the electromigration process and determined that it was an effective and environmentally friendly match. Ten years later, NASA is still using this approach to fight concrete corrosion, and it has also developed a new technology that will further advance these efforts-a liquid galvanic coating applied to the outer surface of reinforced concrete to protect the embedded rebar from corrosion. Surtreat licensed this new coating technology and put it to use at the U.S. Army Naha Port, in Okinawa, Japan. The new coating prevents corrosion of steel in concrete in several applications, including highway and bridge infrastructures, piers and docks, concrete balconies and ceilings, parking garages, cooling towers, and pipelines. A natural compliment to the new coating, Surtreat's Total Performance System provides diagnostic testing and site analysis to identify the scope of problems for each project, manufactures and prescribes site-specific solutions, controls material application, and verifies performance through follow-up testing and analysis.

  20. Conducting polyaniline/multi-wall carbon nanotubes composite paints on low carbon steel for corrosion protection: electrochemical investigations

    Deshpande, P. P.; Vathare, S. S.; Vagge, S. T.; Tomšík, Elena; Stejskal, Jaroslav

    2013-01-01

    Roč. 67, č. 8 (2013), s. 1072-1078. ISSN 0366-6352 R&D Projects: GA ČR GA202/09/1626 Institutional support: RVO:61389013 Keywords : corrosion * polyaniline * conducting polymer Subject RIV: JI - Composite Materials Impact factor: 1.193, year: 2013

  1. Corrosion of steel structures in sea-bed sediment

    Xiutong Wang; Jizhou Duan; Yan Li; Jie Zhang; Shide Ma; Baorong Hou

    2005-04-01

    Seabed sediment (SBS) is a special soil that is covered by seawater. With the developments in marine oil exploitation and engineering, more and more steel structures have been buried in SBS. SBS corrosion has now become a serious problem in marine environment and an important issue in corrosion science. In this paper, approach in the field of SBS corrosion is reviewed. Electrochemical and microbial corrosion factors, corrosion mechanism, measurement of metal corrosion rate, corrosion evaluation and prediction of corrosion are also discussed here.

  2. Pitting corrosion protection of stainless steel by sputter deposited hafnia, alumina, and hafnia-alumina nanolaminate films

    316L stainless steel coated with sputter deposited HfO2, Al2O3, and HfO2-Al2O3 nanolaminate films were subjected to direct current cyclic potentiodynamic polarization (DCP) in Hanks' balanced salt solution electrolyte. Postexposure morphology was characterized by scanning electron microscopy (SEM) with in situ energy dispersive spectroscopy (EDS). SEM/EDS data show that bare steel and steel coated with single-layer HfO2 develop pits with perforated covers. These pits become autocatalytic, consistent with an observed positive DCP hysteresis. On the other hand, SEM/EDS data show that steel coated with Al2O3 and HfO2-Al2O3 nanolaminate films does not develop autocatalytic pits, consistent with an observed negative DCP hysteresis. However, Al2O3 splinters upon polarization whereas the HfO2-Al2O3 nanolaminate remains intact. The areas of worst damage in the nanolaminate correspond to pit cover rupture before autocatalysis, allowing pit and bulk electrolyte to mix and the newly exposed steel surface to repassivate. The films' diverse behavior is discussed in terms of a model for perforated pit growth that requires occlusion until an autocatalytic geometry is established. The authors conclude that the key property a film must have to arrest autocatalytic geometry development is the ability to rupture locally at an early stage of pit growth.

  3. Corrosion of Steels in Steel Reinforced Concrete in Cassava Juice

    Oluwadare, G. O.; Agbaje, O.

    The corrosion of two types of construction steels, ST60Mn and RST37-2♦, in a low cyanide concentration environment (cassava juice) and embedded in concrete had been studied. The ST60 Mn was found to be more corrosion resistant in both ordinary water and the cassava juice environment. The cyanide in cassava juice does not attack the steel but it provides an environment of lower pH around the steel in the concrete which leads to breakdown of the passivating film provided by hydroxyl ions from cement. Other factors such as the curing time of the concrete also affect the corrosion rates of the steel in the concrete. The corrosion rate of the steel directly exposed to cassava juice i.e., steel not embedded in concrete is about twice that in concrete. Long exposure of concrete structure to cassava processing effluent might result in deterioration of such structures. Careful attention should therefore be paid to disposal of cassava processing effluents, especially in a country like Nigeria where such processing is now on the increase.

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

    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.

  5. Corrosion Behavior of Carbon Steels in CCTS Environment

    M. Cabrini

    2016-01-01

    Full Text Available The paper reports the results of an experimental work on the effect of steel microstructures on morphology and protectiveness of the corrosion scale formed in water saturated by supercritical CO2. Two HSLA steels were tested. The microstructures were modified by means of different heat treatments. Weight loss was measured after exposure at CO2 partial pressure of 80 bar and 60°C temperature. The morphology of the scale was analyzed by means of scanning electron microscope (SEM energy-dispersive X-ray spectroscopy (EDX. Cathodic potentiodynamic tests were carried out on precorroded specimens for evaluating the effect of preformed scales on cathodic polarization curves in CO2 saturated sulphuric acid solution at pH 3, which is the value estimated for water saturated by supercritical CO2. The results are discussed in order to evaluate the effect of iron carbide network on scale growth and corrosion rate. Weight loss tests evidenced average corrosion rate values in the range 1–2.5 mm/y after 150-hour exposure. The presence of thick siderite scale significantly reduces the corrosion rate of carbon steel. A slight decrease of the corrosion rate was observed as the scale thickness increases and moving from martensite to microstructures containing carbides.

  6. 起落架用300M超高强度钢应力腐蚀分析与防护%Analysis and Protection of Stress Corrosion of 300M Ultra-high Strength Steel for Landing Gear

    杨永; 张宏明; 吴朝华; 张敏; 蔚海清

    2016-01-01

    Objective To study the protection measures against stress corrosion of 300M ultra-high strength steel for landing gear. Methods The mechanism of stress corrosion cracking of 300M ultra-high strength steel for landing gear was analyzed. Results According to the effects of the source of stress and the stress corrosion environment on the landing gear, optimization was conducted from aspects of the manufacturing process, the surface stress state and the surface treatment methods of the material. Conclusion The stress corrosion resistance of landing gear was improved, and the prevention measures against stress corrosion of landing gear were summarized.%目的 研究起落架用300M超高强度钢的应力腐蚀防护措施.方法 分析起落架用300M超高强度钢应力腐蚀开裂的机理.结果 针对应力源和应力腐蚀环境对起落架的影响,从材料的制造工艺、表面应力状态和表面处理方法 方面进行优化.结论 提高了起落架的抗应力腐蚀能力,并对起落架的防应力腐蚀措施进行总结.

  7. Microbially Influenced Corrosion of Stainless Steels

    Lee, Yong Deuk; Ryu, Seung Ki; Kim Young Ho [POSCO Techanical Researh Laboratories, Pohang (Korea, Republic of)

    1996-06-25

    Microbially Influenced Corrosion(MIC) is often a significant factor in controlling the long-term performance of most structural materials in industrial applications. This papers cover MIC mechanism and evaluation of stainless steels in soil and sea water environments. Papers also cover detection, monitoring and mitigation of MIC, biocides and treatments. (author). 28 refs., 2 tabs., 5 figs.

  8. Stress Corrosion Cracking of Pipeline Steels

    2002-01-01

    This paper provides a review of the differences between high pH and near-neutral pH stress corrosion cracking ofpipeline steels, influencing factors, and mechanisms. The characteristics and historical information on both forms ofSCC are discussed. The prospect for research in the future is also presented.

  9. Electrochemical Fabrication and Characterization of Corrosion-Resistant, Ternary, Lead-Based Alloys as a New Material for Steel Surface Protection

    Aliyev, A. Sh.; Tahirli, H. M.; Elrouby, Mahmoud; Soltanova, N. Sh.; Tagiev, D. B.

    2016-06-01

    This article presents the study of the synthesis of the ternary Pb-Sb-Te alloy on the stainless steel substrate via electrochemical method. The corrosion resistance of the electrodeposited alloy has been investigated via subjecting the electro-synthesized alloy to a corrosive medium containing sulfide ions; this medium is similar to the petroleum refining environment. The resulting film of the electrodeposited alloy was analyzed by the scanning electron microscope, energy-dispersive X-ray analysis, and X-ray diffraction to determine the morphology and the phase structure of the electrodeposited film. It was found that the electrodeposited Pb-Sb-Te alloy thin film is a multiphase composition. The obtained data reveal that the most corrosion-resistant phase is the PbSb2Te4 alloy.

  10. Space Shuttle Corrosion Protection Performance

    Curtis, Cris E.

    2007-01-01

    The reusable Manned Space Shuttle has been flying into Space and returning to earth for more than 25 years. The launch pad environment can be corrosive to metallic substrates and the Space Shuttles are exposed to this environment when preparing for launch. The Orbiter has been in service well past its design life of 10 years or 100 missions. As part of the aging vehicle assessment one question under evaluation is how the thermal protection system and aging protective coatings are performing to insure structural integrity. The assessment of this cost resources and time. The information is invaluable when minimizing risk to the safety of Astronauts and Vehicle. This paper will outline a strategic sampling plan and some operational improvements made by the Orbiter Structures team and Corrosion Control Review Board.

  11. Microbial Corrosion and Cracking in Steel

    Hilbert, Lisbeth Rischel

    1998-01-01

    be based on results from the entire 3 year period, but only selected experimental data primarily from the latest experiments will be presented in detail here.Microbial corrosion of carbon steel under influence of sulphate-reducing bacteria (SRB) is characterised by the formation of both biofilm and...... recommendations in regards to electrochemical monitoring of MIC. The work presented here and further studies are also planned to lead to a Ph.D. thesis on "MIC monitoring based on mechanisms of corrosion".The results of laboratory experiments conducted in the period 1995 to 1997 are summarised. Conclusions will...... corrosion products (ferrous sulphides) on the metal surface. Experiments have been conducted on carbon steel exposed in near neutral (pH 6 to 8.5) saline hydrogen sulphide environment (0 to 100 mg/l total dissolved sulphide) for a period of 14 days. Furthermore coupons have been exposed in a bioreactor for...

  12. Valuation of surfactant Phosphonates synthesized in the protection of metal surfaces against corrosion of mild steel in 0.5M H2SO4 media

    R. Ghibate

    2015-12-01

    Full Text Available In this article, we are interesting to investigate the corrosion inhibition of mild steel in sulfuric acid by two surfactants phospohonates already synthesized namely sodium methyldodecylphosphonate (Pho1 and sodium methyl (11-methacryloyloxyundecyl phosphonate (Pho2. The inhibition performances of Pho1 and Pho2 on mild steel corrosion in 0,5M H2SO4 solution were studied using the electrochemical impedance spectroscopy (EIS, weight loss, and Tafel polarization technics. The experimental results suggest that those surfactants are effective corrosion inhibitors and the inhibition efficiency increases with the increase surfactants concentrations. Polarization measurements proved that the inhibitors behave as mixed-type. EIS diagram appears a large capacitive loop at high frequencies (HF followed by a small inductive loop at low frequencies (LF for Pho2, and the addition of this surfactant inhibitor increases the impedance of electrode. The adsorption of each surfactant on steel surface obeys Langmuir adsorption isotherm. The thermodynamic and kinetic parameters were calculated and discussed. Values of inhibition efficiency calculated from weight loss, Tafel polarization curves, and EIS are in good agreement.

  13. Corrosion protection at a nuclear power station

    Early in the 1970's, the Electricity Supply Commission (Eskom) in South Africa took the decision to construct South Africa's first nuclear fuelled power station. The environment at Koeberg, however, was determined as being particularly corrosive. Eskom was thus faced with the task of selecting corrosion resistant materials and protective coating systems that would provide the required performance in the hostile marine environment. In order to select the correct coating, it was decided to conduct an investigation into the behaviour of various coating systems. All the major coating suppliers in South Africa were invited to provide wet samples of the coating systems that they would recommend. These coatings were applied to mild steel panels which had been prepared in accordance with the coating manufacturer's specification. The panels were then mounted on exposure test racks at various sites. The results of this coating exposure programme were used in the compilation of the corrosion protection specifications for plant and components exposed to the atmosphere at Koeberg. 1 ill

  14. Corrosion resistance testing of high-boron-content stainless steels

    Boron steels, i.e. stainless steels with boron contents of 0.2 to 2.25 wt.%, are employed in nuclear engineering for the manufacture of baskets or wells in which radioactive fissile materials are stored, mostly spent nuclear fuel elements. The resistance of such steels to intergranular corrosion and uniform corrosion was examined in the Strauss solution and in boric acid; the dependence of the corrosion rate of the steels on their chemical composition was investigated, and their resistance was compared with that of AISI 304 type steel. Corrosion resistance tests in actual conditions of ''wet'' compact storage (demineralized water or a weak boric acid solution) gave evidence that boron steels undergo nearly no uniform corrosion and, as electrochemical measurements indicated, match standard corrosion-resistant steels. Corrosion resistance was confirmed to decrease slightly with increasing boron content and to increase somewhat with increasing molybdenum content. (Z.S.). 3 tabs., 4 figs., 7 refs

  15. Some Clarifications Regarding Literature on Atmospheric Corrosion of Weathering Steels

    Morcillo, M.; de la Fuente, D.; Chico, B.; Cano, H.; I. Díaz

    2012-01-01

    Extensive research work has thrown light on the requisites for a protective rust layer to form on weathering steels (WSs) in the atmosphere, one of the most important is the existence of wet/dry cycling. However, the abundant literature on WS behaviour in different atmospheres can sometimes be confusing and lacks clear criteria regarding certain aspects that are addressed in the present paper. What corrosion models best fit the obtained data? How long does it take for the rust layer to stabil...

  16. Corrosion protection and control using nanomaterials

    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 ...

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

    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)

  18. Corrosion Protection of Electrically Conductive Surfaces

    Jian Song; Liangliang Wang; Andre Zibart; Christian Koch

    2012-01-01

    The basic function of the electrically conductive surface of electrical contacts is electrical conduction. The electrical conductivity of contact materials can be largely reduced by corrosion and in order to avoid corrosion, protective coatings must be used. Another phenomenon that leads to increasing contact resistance is fretting corrosion. Fretting corrosion is the degradation mechanism of surface material, which causes increasing contact resistance. Fretting corrosion occurs when there is...

  19. Microbially induced corrosion of carbon steel in deep groundwater environment

    Rajala, Pauliina; Carpén, Leena; Vepsäläinen, Mikko; Raulio, Mari; Sohlberg, Elina; Bomberg, Malin

    2015-01-01

    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 abil...

  20. Corrosion resistance of modern austenitic-ferritic (duplex) stainless steel. Corrosion of special types. (Review)

    Recent data on resistance of modern corrosion-resistant austenitic-ferritic steels to different types of corrosion are generalized. It is shown that these steels are characterized by high resistance to general corrosion in acid, alkali, chloride and other solutions, are not inclined to intercrystalline, pitting and crevice corrosion and are noted for high resistance to corrosion cracking and corrosion fatigue. All this is combined with technological and economical effectiveness. It is advisible to use these steels instead of highly-alloyed and expensive steels and alloys in chemical, power and other industries. 59 refs.; 2 tabs

  1. Reinforcement steel corrosion in passive state and by carbonation: Consideration of galvanic currents and interface steel - concrete defaults

    This thesis aims to study the durability of nuclear waste deep storage structures. The work carried out is essentially an experimental study, and focuses on the corrosion of steel in the passive state with aerated or non-aerated conditions on the one hand, and the corrosion of steel in carbonated concrete during the propagation phase on the other hand. Indeed, the pore solution of concrete in contact with the metal is alkaline (pH between 12 and 13). Under these conditions, steel reinforced concrete remains passive by forming a stable and protective oxide layer (corrosion of steel in the passive state). This passive layer limits the steel corrosion rate at very low values (negligible on a short life time) but not null. For the nuclear waste storage structures due to a very long life time (up to several hundred years), this low corrosion rate can become a risk. Therefore, it is necessary to study the evolution of the oxide layer growth over time. The objectives of the thesis are to study the influence of the steel-concrete interface quality on reinforcement corrosion in passive and active state, and the possible occurrence of galvanic corrosion currents between different reinforcement steel areas. (author)

  2. Corrosion-Activated Micro-Containers for Environmentally Friendly Corrosion Protective Coatings

    Li, Wenyan; Buhrow, J. W.; Zhang, X.; Johnsey, M. N.; Pearman, B. P.; Jolley, S. T.; Calle, L. M.

    2016-01-01

    indicators, inhibitors and self-healing agents. This allows the incorporation of autonomous corrosion control functionalities, such as corrosion detection and inhibition as well as the self-healing of mechanical damage, into coatings. This paper presents technical details on the characterization of inhibitor-containing particles and their corrosion inhibitive effects using electrochemical and mass loss methods.Three organic environmentally friendly corrosion inhibitors were encapsulated in organic microparticles that are compatible with desired coatings. The release of the inhibitors from the microparticles in basic solution was studied. Fast release, for immediate corrosion protection, as well as long-term release for continued protection, was observed.The inhibition efficacy of the inhibitors, incorporated directly and in microparticles, on carbon steel was evaluated. Polarization curves and mass loss measurements showed that, in the case of 2MBT, its corrosion inhibition effectiveness was greater when it was delivered from microparticles.

  3. Interaction between Cathodic Protection and Microbially Influenced Corrosion.

    Bujang Masli, Azlan Bin

    2011-01-01

    The present work studied the interaction between cathodic protection and microbiallyinfluenced corrosion (MIC) on the surface of mild steel. Potential trending wasobserved when the currents were held constant, and current trending was observedwhen potentials were held constant. Scanning electron microscopy and energydispersive x-ray spectroscopy were used to study surface deposits on the samples andfurther understand the result of the interaction. Sul...

  4. Corrosion products release from steel surface into BWR water coolant

    Kritsky, V.G.; Korolev, A.S.; Berezina, I.G.; Sofyin, M.V.

    1986-02-01

    Factors influencing steel corrosion product release and transfer into a BWR primary circuit have been studied and reported on in this paper. The study of corrosion kinetics and corrosion product release was carried out on the samples tested under RBMK NPP condensate-feedwater cycle conditions, as well as, under test rig conditions. The ratio of corrosion product specific mass, transferred to the water, to the whole corrosion product specific mass of steel, formed under the given conditions was determined and used as a criterion, characterizing the extent of corrosion product transfer from the steel surface into the water.

  5. Protective film formation of carbon steel surfaces for corrosion and deposit control in Heavy Water Plant, Manuguru (Paper No. 1.1)

    Heavy Water Plant, Manuguru based on H2S-H2O bi-thermal chemical exchange process employs carbon steel as major material of construction for towers and piping. Several different phases of iron sulphide form as a result of interaction between aqueous H2S and carbon steel. Development of a procedure for formation of stable film on carbon steel as a preconditioning step was carried out based on work done by Heavy Water Division and the experiences of HWP, Kota. Heavy Water Plant, Manuguru was designed for carrying protective film formation of entire exchange unit including vessels, tanks, pipings etc. under dynamic conditions. This paper describes the procedure followed for the protective film formation of carbon steel surfaces at HWP, Manuguru. (author). 2 refs., 3 tabs., 2 figs

  6. An investigation on corrosion protection layers in pipelines transporting hydrocarbons

    Giovanna Gabetta

    2014-10-01

    Full Text Available Chemical reactions between carbon steel, water and chemical species produce corrosion layers (scales on the internal surface of pipelines transporting hydrocarbons. Scales act as a diffusion barrier and prevent the progress of corrosion, a dangerous failure initiator. The protective film (10-100 μm thickness can be removed locally by the action of the internal flow, or by other mechanisms. Adhesion with the substrate and the failure modes of the corrosion layer can be tested by indentation. Some results are presented of experiments performed on specimens with scales grown in a controlled environment.

  7. Corrosion of two kinds of cast steels containing chromium in hot concentrated alkaline

    LI Wei

    2007-02-01

    Full Text Available A typical hot concentrated alkaline corrosion environment exists in alumina metallurgical industry, so that steel materials with outstanding alkaline corrosion resistance are strongly demanded for its processing equipment. In this paper, the corrosion resistance of two kinds of martensitic cast steels containing chromium in static 303g/L NaOH alkaline solution at 85℃ was studied through polarization and potential-time curves, corrosion weight loss and corrosion morphology analysis. Experimental results showed that protection effect by passive film of cast steel containing Cr was temporary. The low carbon steel without Cr content also exhibited chemical passivity in the same solution. The corrosion mode of the tested Cr-containing cast steel was composed of active dissolving corrosion and caustic embrittlement cracking. Dissolving corrosion was the primary mechanism for the induced weight loss, while severe caustic embrittlement cracking was secondary. With the increase of chromium content in the cast steel, the tendency of the caustic embrittlement cracking decreased, while the active dissolving corrosion increased.

  8. Corrosion of two kinds of cast steels containing chromium in hot concentrated alkaline

    LI Wei; LIU Jun-quan; TU Xiao-hui

    2007-01-01

    A typical hot concentrated alkaline corrosion environment exists in alumina metallurgical industry, so that steel materials with outstanding alkaline corrosion resistance are strongly demanded for its processing equipment. In this paper, the corrosion resistance of two kinds of martensitic cast steels containing chromium in static 303 g/L NaOH alkaline solution at 85℃ was studied through polarization and potential-time curves, corrosion weight loss and corrosion morphology analysis. Experimental results showed that protection effect by passive film of cast steel containing Cr was temporary. The low carbon steel without Cr content also exhibited chemical passivity in the same solution. The corrosion mode of the tested Cr-containing cast steel was composed of active dissolving corrosion and caustic embrittlement cracking. Dissolving corrosion was the primary mechanism for the induced weight loss, while severe caustic embrittlement cracking was secondary. With the increase of chromium content in the cast steel, the tendency of the caustic embrittlement cracking decreased, while the active dissolving corrosion increased.

  9. Corrosion behaviour of carbon steel in contact with bentonite under anaerobic condition

    material design, the corrosion products film formed on the surface at 353 K were tight and very small corrosion rates less than 1μm/y was obtained in any cases. While, the corrosion product at 323 K was not protective and larger corrosion rate of 2μm/y was estimated. There was no influence of steel type and welding on the corrosion rate of carbon steel up to 3 years of immersion period. The average corrosion depth of carbon steel overpack was calculated to be ≤ 2 mm by extrapolating the obtained corrosion rate of ≤ 2μm/y to 1000 years, and this estimation was well agreed with natural analogue data. (authors)

  10. Corrosion behaviour of carbon steel in contact with bentonite under anaerobic condition

    Naoki, Taniguchi; Susumu, Kawakami [Japan Nuclear Cycle Development Institute, Tokai-mura, Ibaraki (Japan); Manabu, Kawasaki; Mitsuru, Kubota [Inspection Development Corporation, Tokai-mura, Ibaraki (Japan)

    2004-07-01

    test solution and buffer material design, the corrosion products film formed on the surface at 353 K were tight and very small corrosion rates less than 1{mu}m/y was obtained in any cases. While, the corrosion product at 323 K was not protective and larger corrosion rate of 2{mu}m/y was estimated. There was no influence of steel type and welding on the corrosion rate of carbon steel up to 3 years of immersion period. The average corrosion depth of carbon steel overpack was calculated to be {<=} 2 mm by extrapolating the obtained corrosion rate of {<=} 2{mu}m/y to 1000 years, and this estimation was well agreed with natural analogue data. (authors)

  11. Microbial corrosion and cracking in steel. Assessment of soil corrosivity using an electrochemical soil corrosion probe

    Vendelbo Nielsen, L.

    1998-08-01

    An electrochemical soil corrosion probe has been designed, manufactured, and tested at five different locations in the field. The probe includes facilities for hydrogen permeation measurements, local soil resistivity measurements by the Wenner fourpoint method, and open circuit potential measurements on carbon steel- and high-alloyed (SMO-254) stainless steel electrodes. The carbon steel electrodes were arranged as two sets of three-electrode arrangements. Using these arrangements, electrochemical impedance spectroscopy (EIS), galvanostatic pulse (GP) measurements, and DC polarisation scans were applied for characterisation of the corrosion conditions present in the soil. (au) EFP-95. 21 refs.

  12. On the inhibition of hydrogen sulfide corrosion of steel with Schiff Bases

    The number of the Schiff bases(above 20 compounds) is synthesized. Their impact on the kinetics of electrochemical reactions and steel corrosion behaviour in the two-phase systems electrolyte - hydrocarbon containing H2S, is studied. It is shown, that azomethines, synthesized by the Schiff reaction from aldehydes and aliphatic amines, may serve as water-soluble inhibitors in these systems. The efficiency of steel corrosion protection against hydrogen sulfide corrosion through azomethines depends on their chemical structure and pH media. The effective water-soluble inhibitor of the hydrogen sulfide corrosion - IFKhAN-62 - is developed

  13. Production, properties and application of steels resistant to atmospheric corrosion

    Steels, resistant to atmospheric corrosion, applied in the USSR and abroad, are reviewed. The influence of alloying elements (Cu, P, Cr, Si, Ni, Mo, Mn, As etc) upon resistance against atmospheric corrosion and mechanical properties of rolled steel is discussed. Technological properties, fields of the above steels application as well as the data on the range of product, are presented

  14. Synergistic corrosion inhibition of environment-friendly inhibitors on the corrosion of carbon steel in soft water

    Highlights: • The composite demonstrated synergistic effects and exhibited mixed-type corrosion inhibition behaviour. • The composite showed remarkable corrosion inhibition property at a relatively low dosage. • The composite functioned more environmental-friendly compared to traditional inhibitors. • The composite have been adsorbed on the carbon steel surface as a protective film against corrosion attack. - Abstract: The synergistic effect of the combination of polyaspartic acid (PASP), polyepoxysuccinic acid (PESA), polyamino polyether methylenephosphonate (PAPEMP), sodium gluconate (Glu) and Zn2+ on carbon steel corrosion was investigated using weight loss and electrochemical measurements. The combination of PASP, PESA, PAPEMP, Glu and Zn2+ is an environment-friendly inhibitor and exhibited mixed-type inhibition behaviour. The composite efficiently inhibited corrosion on carbon steel at relatively low dosages in severely corrosive soft water media. Atomic force microscopy (AFM) images and X-ray photoelectron spectroscopic (XPS) spectra further confirmed the formation of a protective film composed of the adsorbed inhibitor molecules on the carbon steel surface against corrosion attack

  15. Pitting corrosion resistant austenite stainless steel

    van Rooyen, D.; Bandy, R.

    A pitting corrosion resistant austenite stainless steel comprises 17 to 28 wt. % chromium, 15 to 26 wt. % nickel, 5 to 8 wt. % molybdenum, and 0.3 to 0.5 wt. % nitrogen, the balance being iron, unavoidable impurities, minor additions made in the normal course of melting and casting alloys of this type, and may optionally include up to 10 wt. % of manganese, up to 5 wt. % of silicon, and up to 0.08 wt. % of carbon.

  16. Atmospheric corrosion of mild steel in Oman

    Gismelseed, Abbasher; Al-Harthi, S. H.; Elzain, M.; Al-Rawas, A. D.; Yousif, A.; Al-Saadi, S.; Al-Omari, I.; Widatallah, H.; Bouziane, K.

    A systematic study has been made of the initial corrosion products which form on mild steel capons exposed near the coastal region of Oman and at some industrial areas. The phases and compositions of the products formed at different periods of exposure were examined by using Mossbauer spectroscopy (295 and 78 K) and X-ray diffraction (XRD) techniques. The results show that lepidocorcite and maghemite are early corrosion products and goethite starts to form after 2 months of metal exposure to the atmosphere. Akaganeite is an early corrosion product but it forms in marine environments only, which reflects the role of chlorine effect in the atmosphere. The 12 months coupons showed the presence of goethite, lepidocorcite and maghemite, but no akaganeite being seen in the products of one of the studied areas.

  17. Atmospheric corrosion of mild steel in Oman

    A systematic study has been made of the initial corrosion products which form on mild steel capons exposed near the coastal region of Oman and at some industrial areas. The phases and compositions of the products formed at different periods of exposure were examined by using Moessbauer spectroscopy (295 and 78 K) and X-ray diffraction (XRD) techniques. The results show that lepidocorcite and maghemite are early corrosion products and goethite starts to form after 2 months of metal exposure to the atmosphere. Akaganeite is an early corrosion product but it forms in marine environments only, which reflects the role of chlorine effect in the atmosphere. The 12 months coupons showed the presence of goethite, lepidocorcite and maghemite, but no akaganeite being seen in the products of one of the studied areas.

  18. Atmospheric corrosion of mild steel in Oman

    Gismelseed, Abbasher, E-mail: abbasher@squ.edu.om; Al-Harthi, S. H.; Elzain, M.; Al-Rawas, A. D.; Yousif, A.; Al-Saadi, S.; Al-Omari, I.; Widatallah, H.; Bouziane, K. [College of Science, Department of Physics (Oman)

    2006-01-15

    A systematic study has been made of the initial corrosion products which form on mild steel capons exposed near the coastal region of Oman and at some industrial areas. The phases and compositions of the products formed at different periods of exposure were examined by using Moessbauer spectroscopy (295 and 78 K) and X-ray diffraction (XRD) techniques. The results show that lepidocorcite and maghemite are early corrosion products and goethite starts to form after 2 months of metal exposure to the atmosphere. Akaganeite is an early corrosion product but it forms in marine environments only, which reflects the role of chlorine effect in the atmosphere. The 12 months coupons showed the presence of goethite, lepidocorcite and maghemite, but no akaganeite being seen in the products of one of the studied areas.

  19. To the corrosion of austenitic steels in sodium loops

    This report describes the comparison between experimental corrosion and calculated corrosion effects on austenitic steels exposed to liquid sodium. As basis for the calculations served a diffusion model. The comparison showed that the model is able to predict the corrosion effects. In addition the model was used to calculate the corrosion effect along an actual fuel rod. (orig.)

  20. Galvanic corrosion between carbon steel 1018 and Alloy 600 in crevice with boric acid solution

    This work dealt with the evaluation of galvanic corrosion rate in a corrosion cell having annular gap of 0.5 mm between carbon steel 1018 and alloy 600 as a function of temperature and boron concentration. Temperature and boron concentration were ranged from 110 to 300 .deg. C and 2000∼10000 ppm, respectively. After the operating temperature of the corrosion cell where the electrolyte was injected was attained at setting temperature, galvanic coupling was made and at the same time galvanic current was measured. The galvanic corrosion rate decreased with time, which was described by corrosion product such as protective film as well as boric acid deposit formed on the carbon steel with time. From the galvanic current obtained as a function of temperature and boron concentration, it was found that the galvanic corrosion rate decreased with temperature while the corrosion rate increased with boron concentration. The experimental results obtained from galvanic corrosion measurement were explained by adhesive property of corrosion product such as protective film, boric acid deposit formed on the carbon steel wall and dehydration of boric acid to be slightly soluble boric acid phase. Moreover the galvanic corrosion rate calculated using initial galvanic coupling current instead of steady state coupling current was remarked, which could give us relatively closer galvanic corrosion rate to real pressurized water reactor

  1. Electrochemical behavior and corrosion protection performance of bis-[triethoxysilylpropyl] tetrasulfide silane films modified with TiO{sub 2} sol on 304 stainless steel

    Chen, Shougang, E-mail: sgchen@ouc.edu.cn; Cai, Yuchen; Zhuang, Chen; Yu, Meiyan; Song, Xianwang; Zhang, Yuping

    2015-03-15

    Highlights: • The TiO{sub 2} sol/BTESPT composite films were prepared on 304 SS surface. • TiO{sub 2} sol/BTESPT composite films exhibit strong adhesion force and good compactness. • TiO{sub 2} sol/BTESPT composite films provided superior corrosion resistance ability. - Abstract: The corrosion protection ability of bis-[triethoxysilylpropyl]tetrasulfide/TiO{sub 2} composite films was evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy in this paper. The electrochemical results show that the composite films modified with TiO{sub 2} sol exhibited superior corrosion protection performance compared to single bis-[triethoxysilylpropyl]tetrasulfide (BTESPT) silane films. The durability and reaction mechanism of BTESPT films and BTESPT/TiO{sub 2} composite films were further studied by electrochemical impedance spectroscopy, scanning electron microscopy, reflection absorption Fourier infrared spectroscopy and X-ray photoelectron spectroscopy, the experimental results revealed the loading of TiO{sub 2} sol into the porous part of the silane network, which not only increases the compactness and durability of silane films but also improves the interfacial bonding force due to formation of Si−O−Ti bonds. After 15 days immersion in 3.5 wt.% NaCl solution, the BTESPT/TiO{sub 2} composite films still had good corrosion resistance ability.

  2. Electrochemical behavior and corrosion protection performance of bis-[triethoxysilylpropyl] tetrasulfide silane films modified with TiO2 sol on 304 stainless steel

    Highlights: • The TiO2 sol/BTESPT composite films were prepared on 304 SS surface. • TiO2 sol/BTESPT composite films exhibit strong adhesion force and good compactness. • TiO2 sol/BTESPT composite films provided superior corrosion resistance ability. - Abstract: The corrosion protection ability of bis-[triethoxysilylpropyl]tetrasulfide/TiO2 composite films was evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy in this paper. The electrochemical results show that the composite films modified with TiO2 sol exhibited superior corrosion protection performance compared to single bis-[triethoxysilylpropyl]tetrasulfide (BTESPT) silane films. The durability and reaction mechanism of BTESPT films and BTESPT/TiO2 composite films were further studied by electrochemical impedance spectroscopy, scanning electron microscopy, reflection absorption Fourier infrared spectroscopy and X-ray photoelectron spectroscopy, the experimental results revealed the loading of TiO2 sol into the porous part of the silane network, which not only increases the compactness and durability of silane films but also improves the interfacial bonding force due to formation of Si−O−Ti bonds. After 15 days immersion in 3.5 wt.% NaCl solution, the BTESPT/TiO2 composite films still had good corrosion resistance ability

  3. The effect of organic matter associated with the corrosion products on the corrosion of mild steel in the Arabian Sea

    Bhosle, N.B.; Wagh, A.B.

    the corrosion of mild steel and the temperature and dissolved oxygen of seawater. In contrast to this, the corrosion and mild steel was inversely related to the organic carbon and water extractable carbohydrates associated with the corrosion products of mild...

  4. Increasing corrosion resistance of carbon steels by surface laser cladding

    Polsky, V. I.; Yakushin, V. L.; Dzhumaev, P. S.; Petrovsky, V. N.; Safonov, D. V.

    2016-04-01

    This paper presents results of investigation of the microstructure, elemental composition and corrosion resistance of the samples of low-alloy steel widely used in the engineering, after the application of laser cladding. The level of corrosion damage and the corrosion mechanism of cladded steel samples were established. The corrosion rate and installed discharge observed at the total destruction of cladding were obtained. The regularities of structure formation in the application of different powder compositions were obtained. The optimal powder composition that prevents corrosion of samples of low-carbon low-alloy steel was established.

  5. Influence of alloying elements on the corrosion properties of shape memory stainless steels

    Highlights: ► The corrosion properties of three Fe–Mn–Si–Cr–Ni–(Co) shape-memory stainless steels (SMSSs) were compared with those of a type 304 (SS 304) austenitic stainless steel. ► A considerably high Si content (about 40 at%) is present in the anodic passive films formed on SMSSs in 0.5 M H2SO4 solution. ► The high protectiveness of the anodic passive film formed on SMSSs in 0.5 M H2SO4 solution results from a protective film consisting of a (Fe, Cr)–mixed silicate. ► The SMSSs exhibited higher corrosion resistance than SS 304 in highly oxidizing environments. ► The SMSSs showed poor corrosion resistance in 3.5% NaCl solution compared to that of SS 304. - Abstract: The corrosion properties of three Fe–Mn–Si–Cr–Ni–(Co) shape memory stainless steels were studied based on X-ray photoelectron spectroscopy (XPS) analyses, immersion and polarization tests. The test results were compared with those of a type 304 austenitic stainless steel. The XPS analyses indicated substantial Si content in the anodic passive films formed on shape memory stainless steels in sulfuric acid solution and that the high protectiveness of these films results from a protective film consisting of a (iron, chromium)–mixed silicate. The corrosion rate of the shape memory stainless steels in boiling nitric acid solution was lower than that of austenitic stainless steel. The high silicon content was found to play an important role in the corrosion behavior of these shape memory alloys in highly oxidizing environments. Due to their high manganese content, the shape memory stainless steels showed poor corrosion behavior in 3.5% sodium chloride solution when compared with austenitic stainless steel.

  6. METHOD FOR ARRANGEMENT OF HIGH-STRENGTH CORROSION-RESISTANT FOR EFFICIENT PROTECTION OF STEEL PIPELINES OPERATED IN THE EXTREME NORTH

    I. S. Surovtsev; Yu. M. Borisov; S. I. Matreninsky; R. I. Sapelkin

    2011-01-01

    Problem statement. At present, the problem of main pipeline protection from corrosion is extremelyimportant. Principal gas-transport routes have the biggest length in the North areas whereclimatic and geotechnical conditions are adverse. Scientists of Voronezh State University of Architectureand Civil Engineering have developed new material, rubber concrete. This material isbased on liquid oligodienes and has unique set of operational characteristics. The material can beefficiently used as in...

  7. Corrosion of steel in concrete in cooling water walls. Report part 3 - Corrosion of steel in water saturated concrete

    corrosion, is probably caused by galvanic corrosion as a consequence of incomplete cathodic protection of stainless steel surfaces within the pumps. Single rebar's being isolated from the rest of the reinforcement can be exposed to stray current corrosion if they are located close to a cathodically protected structure having a high demand for protective current. Concrete structures of greater extent can be exposed to stray current interference caused by high voltage direct current transmission lines located in the neighbourhood. Future installations of cathodic protection in extended culverts should not imply connection of separate parts to each other. The risk of alternating current corrosion is judged to be minimal. If it was not for the corrosion observed on reinforcement on the Oeland Bridge and in Gothenburg harbour, which until now has not been explained, corrosion should be possible to exclude in other positions than the splash zone, walls externally exposed to air and in the vicinity to unprotected structures of stainless steel

  8. Natural Corrosion Inhibitors for Steel Reinforcement in Concrete — a Review

    Raja, Pandian Bothi; Ghoreishiamiri, Seyedmojtaba; Ismail, Mohammad

    2015-04-01

    Reinforced concrete is one of the widely used construction materials for bridges, buildings, platforms and tunnels. Though reinforced concrete is capable of withstanding a large range of severe environments including marine, industrial and alpine conditions, there are still a large number of failures in concrete structures for many reasons. Either carbonation or chloride attack is the main culprit which is due to depassivation of reinforced steel and subsequently leads to rapid steel corrosion. Among many corrosion prevention measures, application of corrosion inhibitors play a vital role in metal protection. Numerous range of corrosion inhibitors were reported for concrete protection that were also used commercially in industries. This review summarizes the application of natural products as corrosion inhibitors for concrete protection and also scrutinizes various factors influencing its applicability.

  9. Corrosion inhibition of carbon steel by sodium metavanadate

    VIJAYA GOPAL SRIBHARATHY

    2012-08-01

    Full Text Available The inhibition efficiency of sodium metavanadate (SMV-adipic acid (AA system in controlling corrosion of carbon steel in an aqueous solution containing 60 ppm of Cl- has been evaluated by weight-loss method; 250 ppm of SMV exhibits inhibition efficiency of 56 %. Addition of adipic acid to SMV improves the inhibition efficiency of the system. The formulation consisting of 250 ppm of SMV and 250 ppm of adipic acid has inhibition efficiency of 98 %. A synergistic effect exists between SMV and adipic acid with the synergism parameters greater than 1. Mecha¬nistic aspects of corrosion inhibition have been studied by electrochemical methods like potentiodynamic polarization and electrochemical impedance spectroscopy. FTIR spectra reveal that the protective film consists of Fe2+-SMV complex and Fe2+-adipic acid complex. The protective film has been analyzed by fluorescence spectra, SEM and EDAX.

  10. Some Clarifications Regarding Literature on Atmospheric Corrosion of Weathering Steels

    I. Díaz

    2012-01-01

    Full Text Available Extensive research work has thrown light on the requisites for a protective rust layer to form on weathering steels (WSs in the atmosphere, one of the most important is the existence of wet/dry cycling. However, the abundant literature on WS behaviour in different atmospheres can sometimes be confusing and lacks clear criteria regarding certain aspects that are addressed in the present paper. What corrosion models best fit the obtained data? How long does it take for the rust layer to stabilize? What is the morphology and structure of the protective rust layer? What is an acceptable corrosion rate for unpainted WS? What are the guideline environmental conditions, time of wetness (TOW, SO2, and Cl−, for unpainted WS? The paper makes a review of the bibliography on this issue.

  11. High temperature (salt melt) corrosion tests with ceramic-coated steel

    Thermal recycling of refuse in waste-to-energy plants reduces the problems connected to waste disposal, and is an alternative source of electric energy. However, the combustion process in waste incinerators results in a fast degradation of the steam-carrying superheater steel tubes by corrosive attack and abrasive wear. Higher firing temperatures are used to increase their efficiency but lead to higher corrosion rates. It is more economical to apply protective coatings on the superheater steel tubes than to replace the base material. In-situ tests were conducted in a waste-to-energy plant first in order to identify and quantify all involved corrosive elements. Laboratory scale experiments with salt melts were developed accordingly. The unprotected low-alloyed steel displayed substantial local corrosion. Corrosion was predominant along the grain boundaries of α-ferrite. The corrosion rate was further increased by FeCl3 and a mixture of HCL and FeCl3. Coatings based on pre-ceramic polymers with specific filler particles were engineered to protect superheater tubes. Tests proved their suitability to protect low-alloYed steel tubes from corrosive attack under conditions typical for superheaterS in waste incinerators, rendering higher firing temperatures in waste-to-energy plants possible. - Highlights: • Corrosion wall thickness losses of 400 μm/2 weeks occurred in a waste incinerator. • Abrasion is a major problem on superheater tubes in waste incinerators. • Laboratory salt melt tests can simulate metal corrosion in waste incinerators. • Corrosion protection coatings for steel (temperature: max. 530 °C) were developed. • Higher steam temperatures are possible in WIs with the developed coatings

  12. Boric acid corrosion of low alloy steel

    In the last decade, the industry has been aware of a potential loss of coolant accident (LOCA) per the following scenario: primary water stress corrosion cracking (PWSCC) of a primary system component or weld leads to a coolant leak, the coolant corrodes a low alloy steel structural component (e.g., the reactor vessel (RV) or the reactor vessel head (RVH)), and corrosion degrades the pressure boundary leading to a loss of coolant accident. The industry has taken several steps to address this concern, including replacement of the most susceptible components (RVH replacement), enhanced inspection (both NDE of components and visual inspections for boric acid deposits), and safety analyses to determine appropriate inspection intervals. Although these measures are generally thought to have adequately addressed this issue, there have been some uncertainties in the safety analyses which the industry has sought to address in order to quantify the extent of conservatism in the safety analyses. Specifically, there has been some uncertainty regarding the rate of boric acid corrosion under various conditions which might arise due to a PWSCC leak and the extent to which boric acid deposits are retained near the leak under various geometries. This paper reviews the results of the Electric Power Research Institute (EPRI) Materials Reliability Program (MRP) boric acid corrosion (BAC) test programs conducted over the last 8 years, focusing on the most recent results of full-scale mockup testing of CRDM nozzle and bottom mounted nozzle (BMN) configurations. The main purpose of this presentation is to provide an overview of the latest understanding of the risk of boric acid corrosion as it is informed by the results of the testing conducted over the last eight years. The rate of boric acid corrosion has been found to be a function of many factors, including initial chemistry, the extent of concentration due to boiling, the temperature at which concentration takes place, the velocity

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

    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.

  14. Corrosion inhibition in 2.0 M sulfuric acid solutions of high strength maraging steel by aminophenyl tetrazole as a corrosion inhibitor

    Sherif, El-Sayed M., E-mail: emsherif@gmail.com [Center of Excellence for Research in Engineering Materials (CEREM), Advanced Manufacturing Institute, King Saud University, PO. Box 800, Al-Riyadh 11421 (Saudi Arabia); National Research Centre (NRC), Electrochemistry and Corrosion Laboratory, Department of Physical Chemistry, National Research Centre (NRC), Dokki, 12622 Cairo (Egypt)

    2014-02-15

    The corrosion of high strength maraging steel after varied immersion times in concentrated solution, 2.0 M, of sulfuric acid has been investigated. The work was also extended to study the effect of 5-(3-aminophenyl)-tetrazole (APTA) on the inhibition of the steel corrosion. The study has been carried out using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and scanning electron microscope (SEM) along with energy dispersive X-ray analyzer (EDX) investigations. EIS spectra showed that the corrosion and polarization resistances decrease with increasing the immersion time of the steel before measurement and increase in the presence of APTA and the increase of its concentration. Polarization data agreed with the EIS measurements and indicated that the increase of immersion time increases the corrosion of steel by increasing its corrosion current and corrosion rate and lowering its polarization resistance. On the other hand, the addition of APTA and the increase of its concentration minimized the corrosion of steel through decreasing the corrosion current and corrosion rate and increasing the polarization resistance at all exposure test periods. SEM and EDX investigations confirmed that the inhibition of the maraging steel in the 2.0 M H{sub 2}SO{sub 4} solutions is achieved via the adsorption of the APTA molecules onto the steel protecting its surface from being dissolved easily.

  15. Corrosion inhibition in 2.0 M sulfuric acid solutions of high strength maraging steel by aminophenyl tetrazole as a corrosion inhibitor

    The corrosion of high strength maraging steel after varied immersion times in concentrated solution, 2.0 M, of sulfuric acid has been investigated. The work was also extended to study the effect of 5-(3-aminophenyl)-tetrazole (APTA) on the inhibition of the steel corrosion. The study has been carried out using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and scanning electron microscope (SEM) along with energy dispersive X-ray analyzer (EDX) investigations. EIS spectra showed that the corrosion and polarization resistances decrease with increasing the immersion time of the steel before measurement and increase in the presence of APTA and the increase of its concentration. Polarization data agreed with the EIS measurements and indicated that the increase of immersion time increases the corrosion of steel by increasing its corrosion current and corrosion rate and lowering its polarization resistance. On the other hand, the addition of APTA and the increase of its concentration minimized the corrosion of steel through decreasing the corrosion current and corrosion rate and increasing the polarization resistance at all exposure test periods. SEM and EDX investigations confirmed that the inhibition of the maraging steel in the 2.0 M H2SO4 solutions is achieved via the adsorption of the APTA molecules onto the steel protecting its surface from being dissolved easily.

  16. Influence of burnishing on stress corrosion cracking susceptibility of duplex steel

    J. Łabanowski

    2006-09-01

    Full Text Available Purpose: of the current study was to investigate the usability of burnishing-inducted surface enhancement method for improve the stress corrosion cracking resistance of duplex stainless steel.Design/methodology/approach: The surface layers upon round in cross section specimens were performed through burnishing treatment. Corrosion tests were performed with the use of Slow Strain Rate Test technique in inert (glycerin and aggressive (boiling 35% MgCl2 solution environments.Findings: It was shown that burnishing treatment increases corrosion resistance of the steel. Stress corrosion cracking resistance depends on the magnitude of cold work at surface layers. High level of cold work decreases corrosion resistance.Research limitations/implications: This study does not indicate the optimum stress level and stress distribution in surface layers for the best corrosion resistance. It is necessary to continue the research to determine burnishing parameters for demanded properties of duplex steel surface layers.Practical implications: The burnishing treatment can significantly improve stress corrosion resistance of specified parts of chemical installations working in the contact with aggressive media. Such parts as valve parts or propeller shafts can be successfully protected against corrosion attack.Originality/value: Burnishing surface enhancement for constructional parts made of duplex stainless steels exposed to corrosive environments has not been reported in literature. Application of this technology can increase life-time of chemical installation devices and improve their reliability.

  17. Corrosion Protection of Electrically Conductive Surfaces

    Jian Song

    2012-11-01

    Full Text Available The basic function of the electrically conductive surface of electrical contacts is electrical conduction. The electrical conductivity of contact materials can be largely reduced by corrosion and in order to avoid corrosion, protective coatings must be used. Another phenomenon that leads to increasing contact resistance is fretting corrosion. Fretting corrosion is the degradation mechanism of surface material, which causes increasing contact resistance. Fretting corrosion occurs when there is a relative movement between electrical contacts with surfaces of ignoble metal. Avoiding fretting corrosion is therefore extremely challenging in electronic devices with pluggable electrical connections. Gold is one of the most commonly used noble plating materials for high performance electrical contacts because of its high corrosion resistance and its good and stable electrical behavior. The authors have investigated different ways to minimize the consumption of gold for electrical contacts and to improve the performance of gold plating. Other plating materials often used for corrosion protection of electrically conductive surfaces are tin, nickel, silver and palladium. This paper will deal with properties and new research results of different plating materials in addition to other means used for corrosion protection of electrically conductive surfaces and the testing of corrosion resistance of electrically conductive surfaces.

  18. Microbially induced corrosion of carbon steel in deep groundwater environment

    Rajala, Pauliina; Carpén, Leena; Vepsäläinen, Mikko; Raulio, Mari; Sohlberg, Elina; Bomberg, Malin

    2015-01-01

    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 3 and 8 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. PMID:26257707

  19. Microbially induced corrosion of carbon steel in deep groundwater environment

    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.

  20. Microbially induced corrosion of carbon steel in deep groundwater environment.

    Rajala, Pauliina; Carpén, Leena; Vepsäläinen, Mikko; Raulio, Mari; Sohlberg, Elina; Bomberg, Malin

    2015-01-01

    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 3 and 8 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. PMID:26257707

  1. Microbiological Corrosion in Low Carbon Steels

    O. Medina–Custodio

    2009-01-01

    Full Text Available The Microbiologically Induced Corrosion affects several industries, such as oil industry where it is estimated that 20% to 30% pipes failures are related with microorganism . The chemical reactions generate ions transfer, this validate the use of electrochemical techniques for its analysis. Coupons submerged in a nutritional medium with presence and absence of three different microorganisms during two periods, 48 hours and 28 days we restudied. Polarization resistance (Rp and Electrochemical Impedance Spectroscopy (EIS techniques we re applied to determine the corrosivity of the systems. The results show a greater corrosive effect of abiotic system, this indicates a microorganisms protection effect to the metal, opposite to the first hypothesis. This result was ratified observing surfaces coupons by using Scanning Electron Microscopy (SEM technique. A possible mechanism based on Evans – Tafel graph is proposed to explain inhibitor microorganism effect.

  2. Atmospheric Corrosion on Steel Studied by Conversion Electron Moessbauer Spectroscopy

    In order to investigate initial products on steel by atmospheric corrosion, conversion electron Moessbauer measurements were carried out at temperatures between 15 K and room temperature. From the results obtained at low temperatures, it was found that the corrosion products on steel consisted of ferrihydrite.

  3. Isomers of Poly Aminophenol: Chemical Synthesis, Characterization, and Its Corrosion Protection Aspect on Mild Steel in 1 M HCl

    G. Thenmozhi

    2014-01-01

    Full Text Available The oxidative chemical polymerizations of three isomers of aminophenol, ortho, meta, and para (PoAP, PmAP, and PpAP, were performed in aqueous HCl using ammonium persulfate as an oxidant at 0–3°C. The synthesized polymers were characterized by employing elemental analysis, GPC, UV-VIS-NIR, FT-IR, XRD, and TGA. The corrosion inhibition effect of these three polymers on mild steel in 1 M HCl solution was studied by using electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy. These measurements reveal that the inhibition efficiency obtained by these polymers increased by increasing their concentration. The inhibition efficiency follows the order PpAP > PoAP > PmAP. The results further revealed that PpAP at a concentration of 250 mg/L furnishes maximum inhibition efficiency (96.5%. Polarization studies indicated that these three polymers act as the mixed type corrosion inhibitors.

  4. Marine atmospheric corrosion of carbon steels

    Morcillo, Manuel

    2015-06-01

    Full Text Available Basic research on marine atmospheric corrosion of carbon steels is a relatively young scientific field and there continue to be great gaps in this area of knowledge. The presence of akaganeite in the corrosion products that form on steel when it is exposed to marine atmospheres leads to a notable increase in the corrosion rate. This work addresses the following issues: (a environmental conditions necessary for akaganeite formation; (b characterisation of akaganeite in the corrosion products formed; (c corrosion mechanisms of carbon steel in marine atmospheres; (d exfoliation of rust layers formed in highly aggressive marine atmospheres; (e long-term corrosion rate prediction; and (f behaviour of weathering steels. Field research has been carried out at Cabo Vilano wind farm (Camariñas, Galicia in a wide range of atmospheric salinities and laboratory work involving the use of conventional atmospheric corrosion techniques and near-surface and bulk sensitive analytical techniques: scanning electron microscopy (SEM/energy dispersive spectrometry (EDS, X-ray diffraction (XRD, Mössbauer spectroscopy and SEM/μRaman spectroscopy.La investigación fundamental en corrosión atmosférica marina de aceros al carbono es un campo científico relativamente joven que presenta grandes lagunas de conocimiento. La formación de akaganeíta en los productos de corrosión que se forman sobre el acero cuando se expone a atmósferas marinas conduce a un incremento notable de la velocidad de corrosión. En el trabajo se abordan las siguientes cuestiones: (a condiciones ambientales necesarias para la formación de akaganeíta, (b caracterización de la akaganeíta en los productos de corrosión formados, (c mecanismos de corrosión del acero al carbono en atmósferas marinas, (d exfoliación de las capas de herrumbre formadas en atmósferas marinas muy agresivas, (e predicción de la velocidad de corrosión a largo plazo, y (f comportamiento de aceros patinables. La

  5. Atmospheric corrosion of galvanized steel in a marine environment

    Atmospheric corrosion is the electrochemical process of metal deterioration from the action of atmospheric factors, both meteorological as well as chemical. Metals deteriorate due to their spontaneous oxidation when their surface is moistened with a film of condensed water, dew, fog or rain and this process leads to the formation of a protective film that acts as a physical barrier between the metal and the environment. However, this layer of corrosion can become a non protective film, due to a physical discharge or a partial dissolution of some soluble corrosion products of the material (galvanized steel) during rainfall or in condensed water on the material's surface. This process is known as metal runoff. In order to estimate the runoff process for galvanized steel and to study its behavior to atmospheric corrosion in a marine environment, samples of 10x10x0,6cm galvanized steel, with a coating thickness of 100 m Zn, were exposed in the city of Valparaiso, Region V, Chile. The atmospheric station is located at lat. 32AS and long. 71oW, classified according to ISO 9223 to 9226 as C2, S1 and P1, with a humidification time of 0.6 and chloride ion and sulfur dioxide content of 40.65 mgm-2day-1 and 7.18 mgm-2day-1, respectively. The deterioration of the galvanized steel was evaluated by weight loss measurements, determination of 'in situ' corrosion potential and morphology of the attack using scanning electron microscopy (SEM). The composition of the corrosion products was determined by X-ray diffraction (XRD). The runoff solutions collected after the rainfall events were analyzed with different techniques to determine the content of Cl- ions, SO4-2 and dissolved solids, and pH and conductivity were measured as well. The concentration of Zn+2 is obtained by atomic adsorption spectroscopy. After four months of exposure of the test pieces preliminary results show that the potential for corrosion of the galvanized steel increased over time, which corroborates the

  6. Investigation of corrosion behavior of Mg-steel laser-TIG hybrid lap joints

    Highlights: ► Galvanic corrosion increases the corrosion rate of the Mg-steel joint. ► Fe splashes lower the corrosion resistance of the joint greatly. ► The effect of grain refinement on the corrosion behavior of the joint is slight. ► Ni or Cu interlayer could not improve the corrosion resistance of fusion zone. ► The arc-sprayed coating could enhance the reliability of weld joint. - Abstract: The paper investigates the corrosion behavior of the lap joint of AZ31 magnesium alloy to Q235 steel with salt solution immersion testing and electrochemical testing. It is demonstrated that grain refinement resulting from the welding process has little effect on the corrosion behavior of the lap joint. However, the cathodic phases formed in the welding process and the galvanic corrosion between magnesium alloy and steel decrease the corrosion resistance of the joint greatly. Besides, neither Cu nor Ni, as filler material, could improve the corrosion resistance of the joint, but the arc-sprayed Al coating acting as a protective layer could.

  7. Corrosion of Steel in Concrete – Thermodynamical Aspects

    Küter, Andre; Møller, Per; Geiker, Mette Rica

    2004-01-01

    The present understanding of selected corrosion phenomena in reinforced concrete is reviewed. Special emphasis is given to chloride induced corrosion. There is a general acceptance of the basic corrosion mechanism for steel in concrete. However different anodic reactions governing the subsequent...

  8. Characterization of Corrosion Products on Carbon Steel Exposed to Natural Weathering and to Accelerated Corrosion Tests

    Renato Altobelli Antunes; Rodrigo Uchida Ichikawa; Luis Gallego Martinez; Isolda Costa

    2014-01-01

    The aim of this work was to compare the corrosion products formed on carbon steel plates submitted to atmospheric corrosion in urban and industrial atmospheres with those formed after accelerated corrosion tests. The corrosion products were characterized by X-ray diffraction, Mössbauer spectroscopy, and Raman spectroscopy. The specimens were exposed to natural weathering in both atmospheres for nine months. The morphologies of the corrosion products were evaluated using scanning electron micr...

  9. Initial Atmospheric Corrosion of Carbon Steel in Industrial Environment

    Han, Wei; Pan, Chen; Wang, Zhenyao; Yu, Guocai

    2015-02-01

    The initial corrosion behavior of carbon steel subjected to Shenyang industrial atmosphere has been investigated by weight-loss measurement, scanning electron microscopy observation, x-ray diffraction, auger electron spectroscopy, and electron probe microanalysis. The experimental results reveal that the corrosion kinetics of the initial corrosion of carbon steel in industrial atmosphere follows empirical equation D = At n , and there is a corrosion rate transition from corrosion acceleration to deceleration; the corrosion products are composed of γ-FeOOH, α-FeOOH, Fe3O4, as well as FeS which is related to the existence of sulfate-reducing bacteria in the rust layers. The effect of dust particles on the corrosion evolution of carbon steel has also been discussed.

  10. MICROBIAL CORROSION OF MILD AND MEDIUM CARBON STEELS

    J. E.O. OVRI; S. I. OKEAHIALAM; O. O. ONYEMAOBI

    2013-01-01

    The role of bacteria in the corrosion of mild and medium carbon steels is reported. The steels were exposed to anaerobic and aerobic, and fresh water (control) environments. The corrosion rates were evaluated at intervals of seven days for a period of 42 days using weight loss and electrochemical methods. The corroded specimens were visually examined and majorities were found to have undergone general corrosion in the three environments (aerobic, anaerobic, and fresh water)....

  11. Corrosion of Stainless Steels of Cryogenic Hydrocarbon Flare Tips Burners

    H. U. Nwosu; A. U. Iwuoha

    2011-01-01

    Analysis of the corrosion resistance of AISI Type 304 Stainless Steel (SS) used in flare tips (burners) of natural gas (NG) extraction facilities is considered to determine the resistance of this grade of austenitic stainless steel to the aggressive corrosive actions of the environment. It was observed that the grade of SS yielded quite early to corrosion attacks which gave effects to scaling, flaking, pitting, material thinning and flare distortions in the burners contrary to expectations. T...

  12. The anaerobic corrosion of carbon steel in concrete

    This is the final report of a 2 year programme aimed at (1) determining the rate of anaerobic corrosion of steel in concrete, (2) investigating the nature of the corrosion products formed on carbon steel embedded in cementitious material under anaerobic conditions and (3) evaluating the effect of hydrogen over-pressures on the rate of anaerobic corrosion. All experiments have been carried out at temperatures in the range 20-300C, ie ambient conditions. 4 refs.; 19 figs.; 6 tabs

  13. Electrochemical Evaluation of Corrosion Inhibitors to Austenistic Stainless Steel

    Yosmari Adames Montero

    2014-03-01

    Full Text Available The use of corrosion inhibitors is one of the most universal methods, and diffused for the protection ofmetals, because they reduce substantially the corrosion losses when they are added in smallconcentrations. At the present work it was carried out the electrochemical tests evaluation of twoinhibitors, A and B, to be used in the chemical cleanings for trays of heat interchanger, which aresuffering thickness losses until its perforation. By the chemical composition analysis, it wasdemonstrated that the metal is an austenistic stainless steel and by electrochemical tests of linearpolarization resistance, electrochemical noise and cyclic sweep, were demonstrated the localizedcorrosion. The best efficiency of the inhibitor A was obtained with one and two percent concentration,while the inhibitor B shows values efficiency near 95% with two percent concentration.

  14. 石油化工业钢结构的大气腐蚀与防护措施%Corrosion and Protection of Steel Structures in Atmospheric Environment of Petrochemical Industry

    朱晓明; 周学杰; 王玮; 纪方奇; 张琳; 林志坚; 胡章枝

    2013-01-01

    Four kinds of standard metals were tested in exposed atmosphere of petrochemical industry so as to determine the corrosive grade of the corrosive atmosphere. In the meantime, eight kinds of anticorro -sive systems were also tested in the exposed corrosive atmosphere so as to evaluate their protective effect. It was found that high concentrations of corrosive mediums such as sulfur dioxide and hydrogen sulfide were present in the atmosphere of petrochemical industry. The atmospheric corrosion grade was from C4 to C5, corresponding to serious corrosion of carbon steel. Moreover, in terms of various protective systems, the one consisting of sprayed Al primer or Zn-rich primer, epoxy micaceous iron oxide intermediate paint, and fluorocarbon resin finish (or acrylic polyurethane coating) possessed the best corrosion resistance and weatherability.%化工大气环境中含有较多的腐蚀性介质,对钢结构腐蚀严重.为了评价石油化工大气环境的腐蚀性,采用4种标准金属材料进行石油化工大气环境现场暴露试验,对石油化工大气环境腐蚀性进行评级;同时选用8种防腐蚀体系试样进行暴露试验,以评价其防护效果.结果表明:石油化工大气环境中含有较高浓度的二氧化硫、硫化氢等腐蚀介质,腐蚀等级属C4~C5级;保护层体系中,由喷铝或富锌底漆、环氧云铁中间漆、氟碳树脂(或丙烯酸聚氨酯)面漆组成的防护体系的综合耐蚀性和耐候性较好.

  15. Electrochemical protection of pointed metallic structures from atmospheric corrosion

    Efficiency of electrochemical protection (ECP) of steel against atmospheric corrosion under thin electrolyte films is investigated. It is shown that the zone of ECP action is restricted by a low conductivity of moisture films, occurring on metals under natural conditions. A method of increasing ECP efficiency by means of using electroconducting coatings applied to standard paint and varnish coatings, is proposed. 6 refs., 2 figs

  16. Experiencies of corrosion and corrosion protection in seawater-cooling systems in the Nordic countries

    This report summarizes the experience of the corrosion resistance of pumps, heat exchangers, valves, and pipings in different seawater-cooling system. For pumps and heat exchangers the experience has been so extensive that a clear picture of todays status can be given. Owing to more scanty data concerning valves and pipes the survey of the corrosion in these components is less well substantiated. The most common pumps in the cooling systems of power stations are vertically extended shaft pumps. To counteract corrosion on column and casing with organic surface coating and on stainless steel shafts and impellers under shutdown conditions, these should be provided with internal and external cathodic protection. The experience of tin and aluminium bronzes in impellers and shafts in such pumps has been so poor - erosion and cavitaion damage - that a change has usually been made to preferentially ferritic-austenitic Mo-alloyd stainless steels. The combination of stainless steel/Ni-Resist 2 D has been found unsatisfactory owing to the occurrence of galvanic corrosion on the latter material. For heat exchangers, titanium has proved to be far and away the best choice. In the optimal blanket solution for a titanium heat exchangers the tubes are seal-welded to tube sheets of explosion-bonded titanium clad steel. For retubing of old condensers a similar procedure with tubes of high-alloy stainless steel in tube sheets of stainless clad steel is of economic interest. The effect of chlorination of the cooling water, however, remains to be clarified before such a procedure can be unreservedly recommended. Pipings of rubber-lined carbon steel or with thick coatings of solvent-free opoxy resin have shown very good corrosion resistance. Tar-epoxy-resin-coated pipes, however, should usually be provided with internal cathodic protection. Cement-lined carbon steel pipes are used with varying results in the offshore industry. Recently, however, pipes of the high slloy stainless steel

  17. Effect of chloride content of molten nitrate salt on corrosion of A516 carbon steel.

    Bradshaw, Robert W.; Clift, W. Miles

    2010-11-01

    The corrosion behavior of A516 carbon steel was evaluated to determine the effect of the dissolved chloride content in molten binary Solar Salt. Corrosion tests were conducted in a molten salt consisting of a 60-40 weight ratio of NaNO{sub 3} and KNO{sub 3} at 400{sup o}C and 450{sup o}C for up to 800 hours. Chloride concentrations of 0, 0.5 and 1.0 wt.% were investigated to determine the effect on corrosion of this impurity, which can be present in comparable amounts in commercial grades of the constituent salts. Corrosion rates were determined by descaled weight losses, corrosion morphology was examined by metallographic sectioning, and the types of corrosion products were determined by x-ray diffraction. Corrosion proceeded by uniform surface scaling and no pitting or intergranular corrosion was observed. Corrosion rates increased significantly as the concentration of dissolved chloride in the molten salt increased. The adherence of surface scales, and thus their protective properties, was degraded by dissolved chloride, fostering more rapid corrosion. Magnetite was the only corrosion product formed on the carbon steel specimens, regardless of chloride content or temperature.

  18. Corrosion of SUS304 stainless steel in oxalic acid solution

    The corrosion rate of oxidized and unoxidized SUS304 stainless steel was measured in 0.1M oxalic acid at 80degC under the potentiostatically polarized conditions. The dissolved amounts of Fe, Cr and Ni were determined by atomic absorption analysis after 166 min of polarization as a function of the potential. The corrosion potential and the sweep potentiostatic polarization curve were also measured in the same solution. The unoxidized specimen was severely attacked at the cathodic potential between -200 and -700 mV vs Ag-AgCl. Similar cathodic corrosion was also found, but with a decreased dissolution rate, for oxidized specimens. Since the corrosion potential of the alloy situated nearly at the boundary of active passive transition, both specimens frequently suffered localized attack due to insufficient passivation during spontaneous immersion. The dissolution rate of the surface oxide was slightly effected by the electrode potential within the active and the passive regions. Therefore, weakly anodic polarization is desirable for the dual purposes of the effective dissolution of surface oxide and the protection of substrate alloy surface. (author)

  19. Enamel coated steel reinforcement for improved durability and life-cycle performance of concrete structures: microstructure, corrosion, and deterioration

    Tang, Fujian

    This study is aimed (a) to statistically characterize the corrosion-induced deterioration process of reinforced concrete structures (concrete cracking, steel mass loss, and rebar-concrete bond degradation), and (b) to develop and apply three types of enamel-coated steel bars for improved corrosion resistance of the structures. Commercially available pure enamel, mixed enamel with 50% calcium silicate, and double enamel with an inner layer of pure enamel and an outer layer of mixed enamel were considered as various steel coatings. Electrochemical tests were respectively conducted on steel plates, smooth bars embedded in concrete, and deformed bars with/without concrete cover in 3.5 wt.% NaCl or saturated Ca(OH)2 solution. The effects of enamel microstructure, coating thickness variation, potential damage, mortar protection, and corrosion environment on corrosion resistance of the steel members were investigated. Extensive test results indicated that corrosion-induced concrete cracking can be divided into four stages that gradually become less correlated with corrosion process over time. The coefficient of variation of crack width increases with the increasing level of corrosion. Corrosion changed the cross section area instead of mechanical properties of steel bars. The bond-slip behavior between the corroded bars and concrete depends on the corrosion level and distribution of corrosion pits. Although it can improve the chemical bond with concrete and steel, the mixed enamel coating is the least corrosion resistant. The double enamel coating provides the most consistent corrosion performance and is thus recommended to coat reinforcing steel bars for concrete structures applied in corrosive environments. Corrosion pits in enamel-coated bars are limited around damage locations.

  20. Understanding corrosion via corrosion product characterization: II. Role of alloying elements in improving the corrosion resistance of Zn-Al-Mg coatings on steel

    Highlights: → Origins of better corrosion resistance of ZnAlMg coatings than galvanized steel. → Comparative study of corrosion products formed on ZnAlMg, ZnMg and Zn coatings. → Modeling of dissolution and precipitation stages of corrosion. → At early stages Mg stabilizes protective zinc basic salts during dry-wet cycling. → At later stages Al dissolves at high pH forming protective layered double hydroxides. - Abstract: Corrosion products are identified on Zn, ZnMg and ZnAlMg coatings in cyclic corrosion tests with NaCl or Na2SO4 containing atmospheres. For Mg-containing alloys the improved corrosion resistance is achieved by stabilization of protective simonkolleite and zinc hydroxysulfate. At later stages, the formation of layered double hydroxides (LDH) is observed for ZnAlMg. According to thermodynamic modeling, Mg2+ ions bind the excess of carbonate or sulfate anions preventing the formation of soluble or less-protective products. A preferential dissolution of Zn and Mg at initial stages of corrosion is confirmed by in situ dissolution measurement. The physicochemical properties of different corrosion products are compared.

  1. Corrosion of Steel in Concrete – Potential Monitoring and Electrochemical Impedance Spectroscopy during Corrosion Initiation and Propagation

    Küter, Andre; Mason, Thomas O.; Geiker, Mette Rica;

    2005-01-01

    investigation on the effect of the steel quality and the steel surface properties on initiation and propagation of chloride-induced reinforcement corrosion. Besides untreated (as received) carbon rebars and stainless rebars, selected surface treatments and galvanization were investigated. The surface treatments...... included grit blasting, electrochemical and hydrochloric acid cleaning (HCl) as well as weathering. The results indicate that the investigated treatments of the carbon steel surface have no major effect on the initiation period, which was approximately 20 days under the actual conditions. The galvanized...... rebar appears to be protected throughout the experimental period to date (200 days), whereas active corrosion of the stainless steel appeared to be initiated after 100 days exposure....

  2. Corrosion behavior of duplex polyaniline/epoxy coating on mild steel in 3% NaCl

    Gvozdenović Milica M.

    2005-01-01

    Full Text Available The corrosion behavior and thermal stability of epoxy coatings electrodeposited on mild steel and on mild steel with electrochemically deposited polyaniline (PANI film were investigated by electrochemical impedance spectroscopy (EIS and thermo gravimetric analysis (TGA. The aim of the paper was to present new findings on the corrosion protection of mild steel by a duplex PANI/-epoxy coating in 3% NaCI solution and to determine the effect of thin PANI film on the protective properties of the coating. PANI film was deposited electrochemically on mild steel from an aqueous solution of 0.5 mol dm"3 sodium benzoate and 0.1 mol dm"3 aniline at a constant current density of 1.5 mA cm"2. Non-pigmented epoxy coatings on mild steel and on mild steel with PANI film were obtained by cathodic electrode position at constant voltage and stirring conditions. The resin concentration in the electrode position bath was 10 wt.% solid dispersion in water at pH 5.7. The applied voltage was 250 V, the temperature 26°C and the deposition time 3 min. It was shown that thin PANI film could be used to modify the surface of mild steel prior to epoxy coating deposition, due to the increased corrosion protection of a duplex PANI/epoxy coating comparing to an epoxy coating on mild steel in 3% NaCl solution.

  3. Corrosion behavior of duplex stainless steel in sulphuric acid

    Duplex stainless steels are alloyed and processed to develop microstructure of roughly equal amounts of ferrite and austenite. Duplex stainless steel constitute a new class of materials because they have balanced amounts of ferrite and austenite. Since they have high content of chromium and molybdenum present, thus they have good corrosion resistance. Their corrosion resistance is double to that of annealed austenitic stainless steels with regard to pitting, crevice corrosion, sulphide stress corrosion, and chloride stress corrosion environments. The corrosion behavior of duplex stainless steel in various concentrations of sulphuric acid was studied. The reactions were carried out by placing the steel specimen in a beaker containing a known concentration of sulphuric acid at room temperature for a definite period. Pits were initiated in duplex stainless steel specimen and the propagation of pits depends upon the concentration of the acid solution in which the sample is in contact. The weight loss for definite period of time were measured and corrosion rates were calculated in millimetres per year. The corrosion rates increases with an increase in acid concentration at room temperature. A comparison of the results obtained from various concentrations of sulphuric acid with the same concentrations of nitric acid is also discussed. (author)

  4. Inhibition properties of self-assembled corrosion inhibitor talloil diethylenetriamine imidazoline for mild steel corrosion in chloride solution saturated with carbon dioxide

    Highlights: •Corrosion inhibitor talloil diethylenetriamine imidazoline effectively protects mild steel from CO2 corrosion. •Quartz crystal microbalance measurements were used to the investigate kinetics of corrosion inhibitor adsorption. •Adsorption of talloil diethylenetriamine imidazoline can be described by Langmuir adsorption isotherm. -- Abstract: The inhibition effect of talloil diethylenetriamine imidazoline (TOFA/DETA imidazoline) on corrosion of mild steel in chloride solutions saturated with CO2 was investigated by weight loss measurements (WL) and atomic force microscopy (AFM). Adsorption mechanism and kinetics of self-assembled (TOFA/DETA imidazoline) monolayers formation on gold were studied using the quartz crystal microbalance measurements (QCM). WL and AFM results demonstrated that TOFA/DETA imidazoline can effectively protect mild steel surface from corrosion. QCM measurements shown that the adsorption of TOFA/DETA imidazoline onto gold follows Langmuir adsorption isotherm and further investigation of the adsorption process will be carried out on a corroding metal surface

  5. Kinetics and structural studies of the atmospheric corrosion of carbon steels in Panama

    The corrosion of a carbon steel was studied in different atmospheres at sites in the Republic of Panama. The weight loss (corrosion penetration) suffered by the carbon steel is related to time by a bilogarithmic law. Moessbauer spectroscopy indicated the rust was composed of non-stoichiometric magnetite (Fe3-xO4), maghemite (γ-Fe2O3), goethite (α-FeOOH) of intermediate particle size, lepidocrocite (γ-FeOOH) and superparamagnetic particles. Magnetite formation is related to the alternating dry-wet cycles. Goethite is related to corrosion penetration by a saturation type of behavior, following a Langmuir type of relationship. Goethite in rust protects steel against further atmospheric corrosion

  6. Materials corrosion and protection at high temperatures

    This book was made from the lectures given in 2010 at the thematic school on 'materials corrosion and protection at high temperatures'. It gathers the contributions from scientists and engineers coming from various communities and presents a state-of-the-art of the scientific and technological developments concerning the behaviour of materials at high temperature, in aggressive environments and in various domains (aerospace, nuclear, energy valorization, and chemical industries). It supplies pedagogical tools to grasp high temperature corrosion thanks to the understanding of oxidation mechanisms. It proposes some protection solutions for materials and structures. Content: 1 - corrosion costs; macro-economical and metallurgical approach; 2 - basic concepts of thermo-chemistry; 3 - introduction to the Calphad (calculation of phase diagrams) method; 4 - use of the thermodynamic tool: application to pack-cementation; 5 - elements of crystallography and of real solids description; 6 - diffusion in solids; 7 - notions of mechanics inside crystals; 8 - high temperature corrosion: phenomena, models, simulations; 9 - pseudo-stationary regime in heterogeneous kinetics; 10 - nucleation, growth and kinetic models; 11 - test experiments in heterogeneous kinetics; 12 - mechanical aspects of metal/oxide systems; 13 - coupling phenomena in high temperature oxidation; 14 - other corrosion types; 15 - methods of oxidized surfaces analysis at micro- and nano-scales; 16 - use of SIMS in the study of high temperature corrosion of metals and alloys; 17 - oxidation of ceramics and of ceramic matrix composite materials; 18 - protective coatings against corrosion and oxidation; 19 - high temperature corrosion in the 4. generation of nuclear reactor systems; 20 - heat exchangers corrosion in municipal waste energy valorization facilities; 21 - high temperature corrosion in oil refining and petrochemistry; 22 - high temperature corrosion in new energies industry. (J.S.)

  7. Electrochemical surface modification technique to impede mild steel corrosion using perfluorooctanoic acid

    Shubha H Natarj

    2016-02-01

    Full Text Available The present work demonstrated that corrosion inhibition efficiency of electrochemically generated organic coat is remarkably effective than self-assembled monolayer (SAM generated by dip coating technique. Perfluorooctanoic Acid (PFOA is used to modify mild steel surface for effective protection. Infrared reflection absorption spectroscopy and contact angle measurements substantiate the modification of mild steel surface and its effect on surface hydrophobicity. A comparison between electrochemical properties of PFOA SAM generated by dip coat method (DC-PFOA and PFOA coat generated by electrochemical method (EC-PFOA is presented. Electrochemical measurements reveal that the corrosion protection efficiency of EC-PFOA (91% is much superior to DC-PFOA (28%.

  8. Corrosion behavior of niobium coated 304 stainless steel in acid solution

    Pan, T. J.; Chen, Y.; Zhang, B.; Hu, J.; Li, C.

    2016-04-01

    The niobium coating is fabricated on the surface of AISI Type 304 stainless steel (304SS) by using a high energy micro arc alloying technique in order to improvecorrosion resistance of the steel against acidic environments. The electrochemical corrosion resistance of the niobium coating in 0.7 M sulfuric acid solutions is evaluated by electrochemical impedance spectroscopy, potentiodynamic polarization and the open circuit potential versus time. Electrochemical measurements indicate that the niobium coating increases the free corrosion potential of the substrate by 110 mV and a reduction in the corrosion rate by two orders of magnitude compared to the substrate alone. The niobium coating maintains large impedance and effectively offers good protection for the substrate during the long-term exposure tests, which is mainly ascribed to the niobium coating acting inhibiting permeation of corrosive species. Finally, the corresponding electrochemical impedance models are proposed to elucidate the corrosion resistance behavior of the niobium coating in acid solutions.

  9. Corrosion and Stress Corrosion Behaviors of Low and Medium Carbon Steels in Agro-Fluid Media

    Ayo Samuel AFOLABI

    2007-01-01

    Full Text Available Investigations were carried out to study critically the corrosion behaviour and Stress Corrosion Cracking (SCC of low and medium carbon steels in cassava and cocoa extracts by weight loss measurement and constant extension to fracture method respectively. The results obtained showed that medium carbon steel is more susceptible to corrosion than low carbon steel in both media. SCC is also more in medium carbon steel than low carbon steel in the two media under study. These deductions are due to higher carbon content in medium carbon steel coupled with various aggressive corrosion constituents contained in these media. Hydrogen embrittlement, as well as carbon cracking, is responsible for SCC of these materials in the agro-fluid media.

  10. CORROSION RESISTANCE OF HOT DIP GALVANIZED STEEL PRETREATED WITH BIS-FUNCTIONAL SILANES MODIFIED WITH NANOALUMINA

    F.J.Shan; C.S.Liu; S.H.Wang; G.C.Qi

    2008-01-01

    The corrosion behavior of hot dip galvanized steel pretreated with bis-[triethoxy-silylpropyl]tetrasulfide (BTESPT) modified with alumina particles was studied.The corrosion resistance of the passiving films was evaluated by Tafel polarization curve and electrochemical impedance spectroscopy.The films formed on the galvanized steel substrate were characterized by Fourier transform infrared spectroscopy and energy dispersive X-ray spectrometry.The surface morphology of the treated hot dip galva-nized steel samples was observed by Field Emission Scanning Electron Microscope. The results show that the pretreatments on the basis of silane films modified with nanoalumina particles have reduced both anodic and cathodic current densities,and increased total impedance in the measured frequency,consequently,improving cor-rosion protection for hot dip galvanized steel during immersion in NaCl solutions compared to chromate films and silane films.

  11. Experiences of corrosion and corrosion protection in seawater systems in the Nordic countries

    A summary is given of the experience of the corrosion resistance of pumps, heat exchangers, valves and pipings in different seawater cooling systems in Scandinavia, including power reactor cooling systems in Finland and Sweden. For pumps and heat exchangers the experience has been so extensive that a clear picture of today's standing can be given. Owing to scanty data concerning valves and pipes, the survey of the corrosion in these components is less well supported. Vertically extended centrifugal pumps are the pumps in general use in power plant cooling systems. To counteract corrosion on pump riser and pump casing having an organic surface coating, and on stainless steel shafts and impellers, these components should be provided with internal and external cathodic protection. For tube and plate type heat exchangers, titanium has proved to be the best material choice. Rubber-enclosed carbon steel pipings, or pipings having a thick coating of epoxy plastic, have shown very strong corrosion resistance in power plant seawater cooling systems. Valves in seawater systems have primarily been affected by corrosion due to poorly executed or damaged organic coating on cast iron. Different seawater-resistant bronzes (red bronze, tin bronze and aluminium bronze) are therefore preferable as valve materials

  12. Corrosion of vessel steel during its interaction with molten corium

    Bechta, S.V. [Scientific Research Technological Institute (NITI), Sosnovy Bor of Leningrad Oblast 188540 (Russian Federation)]. E-mail: bechta@sbor.spb.su; Khabensky, V.B. [Scientific Research Technological Institute (NITI), Sosnovy Bor of Leningrad Oblast 188540 (Russian Federation); Vitol, S.A. [Scientific Research Technological Institute (NITI), Sosnovy Bor of Leningrad Oblast 188540 (Russian Federation); Krushinov, E.V. [Scientific Research Technological Institute (NITI), Sosnovy Bor of Leningrad Oblast 188540 (Russian Federation); Granovsky, V.S. [Scientific Research Technological Institute (NITI), Sosnovy Bor of Leningrad Oblast 188540 (Russian Federation); Lopukh, D.B. [SPb Electrotechnical University (SpbGETU), Professor Popov str., b.5/3, 197376 St. Petersburg (Russian Federation); Gusarov, V.V. [Institute of Silicate Chemistry of Russian Academy of Science (ISC of RAS), Odoevsky str., b. 24/2, 199155 St. Petersburg (Russian Federation); Martinov, A.P. [SPb Electrotechnical University (SpbGETU), Professor Popov str., b.5/3, 197376 St. Petersburg (Russian Federation); Martinov, V.V. [Scientific Research Technological Institute (NITI), Sosnovy Bor of Leningrad Oblast 188540 (Russian Federation); Fieg, G. [Forshungszentrum Karlsruhe (FZK), Institut fur Neutronenphysik and Reaktortechnik, Postfach 3640, D-78021 Karlsruhe (Germany); Tromm, W. [Forshungszentrum Karlsruhe (FZK), Institut fur Neutronenphysik and Reaktortechnik, Postfach 3640, D-78021 Karlsruhe (Germany); Bottomley, D. [Europaeische Kommission, General Direktion GFS, Institut fuer Transurane (ITU), Postfach 2340, 76125 Karlsruhe (Germany); Tuomisto, H. [Fortum Engineering Ltd. 00048 FORTUM, Rajatorpantie 8, Vantaa (Finland)

    2006-07-15

    An experimental examination of the cooled vessel steel corrosion during the interaction with molten corium is presented. The experiments have been conducted on 'Rasplav-2' test facility and followed up with physico-chemical and metallographic analyses of melt samples and corium-specimen ingots. The results discussed in the first part of the paper have revealed specific corrosion mechanisms for air and inert atmosphere above the melt. Models have been proposed based on this information and approximate curves constructed for the estimation of the corrosion rate or corrosion depth of vessel steel in conditions simulated by the experiments.

  13. Atmospheric corrosion of mild steel. Pt. II. Marine atmospheres

    This paper summarizes the results obtained in the MICAT project for mild steel specimens exposed for 1 to 4 years in 47 marine atmospheres in the Ibero-American region. All these atmospheres were characterized for climatology, pollution and corrosion rates according to ISO standards. Complementary morphological and chemical characterization of the steel corrosion product layers (SCPLs) formed in these atmospheres was carried out. The overall analysis of results contributes to understanding, in a systematic way, how atmospheric corrosivity categories can be correlated with corrosion mechanisms. Special aspects of the atmospheres, from pure to mixed marine, were considered. (orig.)

  14. Corrosion induced by cathodic hydrogen in 2205 duplex stainless steel

    Michalska, J.

    2011-05-01

    In this work new results about the influence of cathodic hydrogen on passivity and corrosion resistance of 2205 duplex stainless steel are described. The results were discussed by taking into account hydrogen charged samples and without hydrogen. The corrosion resistance to pitting was qualified with the polarization curves. The conclusion is that, hydrogen deteriorated the passive film stability and corrosion resistance to pitting of 2205 duplex stainless steel. The presence of hydrogen in passive films increases corrosion current density and decreases the potential of the film breakdown. It was also found that degree of susceptibility to hydrogen action was dependent on the hydrogen charging conditions.

  15. Corrosion induced by cathodic hydrogen in 2205 duplex stainless steel

    Michalska, J, E-mail: joanna.k.michalska@polsl.pl [Department of Materials Science, Silesian University of Technology, Krasinskiego 8, 40-019 Katowice (Poland)

    2011-05-15

    In this work new results about the influence of cathodic hydrogen on passivity and corrosion resistance of 2205 duplex stainless steel are described. The results were discussed by taking into account hydrogen charged samples and without hydrogen. The corrosion resistance to pitting was qualified with the polarization curves. The conclusion is that, hydrogen deteriorated the passive film stability and corrosion resistance to pitting of 2205 duplex stainless steel. The presence of hydrogen in passive films increases corrosion current density and decreases the potential of the film breakdown. It was also found that degree of susceptibility to hydrogen action was dependent on the hydrogen charging conditions.

  16. Modeling Corrosion Reactions of Steel in a Dilute Carbonate Solution

    Eliyan, Faysal Fayez; Alfantazi, Akram

    2016-02-01

    This research models the corrosion reactions of a high-strength steel in an aerated, dilute, carbonate solution during a single-cycle voltammetry. Based on a previous study (Eliyan et al. in J Mater Eng Perform 24(6):1-8, 2015) and a literature survey, the corrosion reactions of the cathodic reduction, anodic dissolution, and passivation, as well as the interfacial interactions and the chemistry of the corrosion products are illustrated in schematics. The paper provides a visual guide on the corrosion reactions for steel in carbonate solutions based on the available mechanistic details that were reported and are still being investigated in literature.

  17. In situ 3D monitoring of corrosion on carbon steel and ferritic stainless steel embedded in cement paste

    Highlights: • The morphology of the corrosion of steel in cement paste was studied in situ. • During galvanostatic corrosion, carbon steel reinforcement corroded homogeneously. • On ferritic stainless steel, deep corrosion pits formed and caused wider cracks. • The measured rate of steel loss correlated well with Faraday’s law of electrolysis. - Abstract: In a X-ray microcomputed tomography study, active corrosion was induced by galvanostatically corroding steel embedded in cement paste. The results give insight into corrosion product build up, crack formation, leaching of products into the cracks and voids, and differences in morphology of corrosion attack in the case of carbon steel or stainless steel reinforcement. Carbon steel was homogeneously etched away with a homogeneous layer of corrosion products forming at the steel/cement paste interface. For ferritic stainless steel, pits were forming, concentrating the corrosion products locally, which led to more extensive damage on the cement paste cover

  18. Synergistic inhibition of carbon steel corrosion in seawater by cerium chloride and sodium gluconate

    Highlights: • Significant synergistic effect was determined for cerium and gluconate. • The mixture showed significant corrosion inhibition of carbon steel in seawater. • Predominant anodic inhibition mechanism was observed. • The presence of cerium ions incorporated in the protective layer was confirmed. - Abstract: In this research the effect of cerium (III) chloride heptahydrate (CC) and sodium gluconate (SG) on the corrosion inhibition of carbon steel C45 (1531) in natural seawater has been evaluated using electrochemical methods and scanning electron microscopy (SEM). The results show that substantial corrosion inhibition (94.98%) using CC and SG can be obtained in synergistic manner. Surface analysis confirmed the presence of cerium ions incorporated in the protective layer of carbon steel specimen. SG acts predominantly as anodic inhibitor whereas CC acts as a mixed type inhibitor. Using both inhibitors predominant mechanism of anodic inhibition is observed

  19. Prediction of external corrosion for steel cylinders

    The US Department of Energy (DOE) currently manages the UF6 Cylinder Program (the program). The program was formed to address the depleted-uranium hexafluoride (UF6) stored in approximately 50,000 carbon steel cylinders. The cylinders are located at three DOE sites: the K-25 site (K-25) at Oak Ridge, Tennessee; the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The System Requirements Document (SRD) (LMES 1996a) delineates the requirements of the program. The appropriate actions needed to fulfill these requirements are then specified within the System Engineering Management Plan (SEMP) (LMES 1996b). The report presented herein documents activities that in whole or in part satisfy specific requirements and actions stated in the UF6 Cylinder Program SRD and SEMP with respect to forecasting cylinder conditions. The wall thickness projections made in this report are based on the assumption that the corrosion trends noted will continue. Some activities planned may substantially reduce the rate of corrosion, in which case the results presented here are conservative. The results presented here are intended to supersede those presented previously, as the quality of several of the datasets has improved

  20. Influence of temperature on corrosion rate and porosity of corrosion products of carbon steel in anoxic bentonite environment

    Highlights: •The corrosion rate is not significantly dependent on temperature. •Corrosion products at higher temperatures have different color. •Corrosion products at higher temperatures are more compact. •The change in corrosion products nature is reversible. -- Abstract: The study focuses on the porosity of layers of corrosion products and its impact on corrosion rate of carbon steel in moist bentonite. Measurements were performed in an aggressive Czech type of bentonite – Rokle B75 at temperatures of 90 and 40 °C. Aggressiveness of B75 bentonite consists in low content of chlorides. Presence of chlorides in pore solution allows formation of more protective magnetite. The evaluation was made by electrochemical techniques (red/ox potential, open circuit potential, linear polarization resistance, impedance spectroscopy) and resistometric sensor measurements. The result imply that the higher the temperature the more compact is the layer of corrosion products that slightly decelerates corrosion rate compared to the state at 40 °C. The state of corrosion products at both temperatures is reversible

  1. Investigation of Fecraly Coating on Corrosion Behaviour of Mild Steel

    Joseph B. AGBOOLA

    2009-01-01

    Steel has found wide application in hot rolling equipments in the steel industry and the oil rig structures in sea water. These equipments are frequently subjected to corrosive and temperature condition which causes severe damage to them, hence the need to develop steel suitable to withstand these conditions in terms of surface treatment. This research work investigates the effect of FeCrAlY coating on mild steel under high temperature and aggressive environment. Iron based coatings are used ...

  2. Corrosion-resistant Foamed Cements for Carbon Steels

    Sugama T.; Gill, S.; Pyatina, T., Muraca, A.; Keese, R.; Khan, A.; Bour, D.

    2012-12-01

    The cementitious material consisting of Secar #80, Class F fly ash, and sodium silicate designed as an alternative thermal-shock resistant cement for the Enhanced Geothermal System (EGS) wells was treated with cocamidopropyl dimethylamine oxide-based compound as foaming agent (FA) to prepare numerous air bubble-dispersed low density cement slurries of and #61603;1.3 g/cm3. Then, the foamed slurry was modified with acrylic emulsion (AE) as corrosion inhibitor. We detailed the positive effects of the acrylic polymer (AP) in this emulsion on the five different properties of the foamed cement: 1) The hydrothermal stability of the AP in 200 and #61616;C-autoclaved cements; 2) the hydrolysis-hydration reactions of the slurry at 85 and #61616;C; 3) the composition of crystalline phases assembled and the microstructure developed in autoclaved cements; 4) the mechanical behaviors of the autoclaved cements; and, 5) the corrosion mitigation of carbon steel (CS) by the polymer. For the first property, the hydrothermal-catalyzed acid-base interactions between the AP and cement resulted in Ca-or Na-complexed carboxylate derivatives, which led to the improvement of thermal stability of the AP. This interaction also stimulated the cement hydration reactions, enhancing the total heat evolved during cement’s curing. Addition of AP did not alter any of the crystalline phase compositions responsible for the strength of the cement. Furthermore, the AP-modified cement developed the porous microstructure with numerous defect-free cavities of disconnected voids. These effects together contributed to the improvement of compressive-strength and –toughness of the cured cement. AP modification of the cement also offered an improved protection of CS against brine-caused corrosion. There were three major factors governing the corrosion protection: 1) Reducing the extents of infiltration and transportation of corrosive electrolytes through the cement layer deposited on the underlying CS

  3. Microbial corrosion in weld zone of stainless steel. Stainless ko yosetsubu no biseibutsu fushoku

    Sasaki, E. (National Chemical Laboratory for Industry, Tsukuba (Japan)); Nishimura, M. (Mitsubishi Kakoki Kaisha, Ltd., Tokyo (Japan))

    1992-10-15

    Microbial corrosion may happen wherever water is treated in many kinds of practical metal except titan, such as common steel, copper alloy, stainless steel, and high-nickel alloy. Although microbes causing microbial corrosion are not limited to specified microbes, specially affecting microbes are iron bacteria, iron-oxidizing bacteria, and sulfate-reducing bacteria. mechanism in these microbial corrosion, which is fundamentally caused through formation of oxygen concentration cells and production of metabolites, is complex and different by each microbe. In the case of stainless steel, the corrosion is located mainly in weld zones or heat affected zones, the shape of corrosion is like a pot, and the pattern is a type of pitting corrosion. Microbes are apt to adhere to the surface near weld zones, then oxygen becomes consequently insufficient beneath the surface, where the self-mending capacity of passive films is deprived, resulting in occurrence of pitting corrosion. For protection of microbial corrosion, it is essential to control water so that habitation of microbes is not formed. 9 refs., 3 figs.

  4. 49 CFR 192.461 - External corrosion control: Protective coating.

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false External corrosion control: Protective coating... for Corrosion Control § 192.461 External corrosion control: Protective coating. (a) Each external protective coating, whether conductive or insulating, applied for the purpose of external corrosion...

  5. Corrosion behavior of carbon steels under tuff repository environmental conditions

    Carbon steels may be used for borehole liners in a potential high-level nuclear waste repository in tuff in Nevada. Borehole liners are needed to facilitate emplacement of the waste packages and to facilitate retrieval of the packages, if required. Corrosion rates of low carbon structural steels AISI 1020 and ASTM A-36 were determined in J-13 well water and in saturated steam at 1000C. Tests were conducted in air-sparged J-13 water to attain more oxidizing conditions representative of irradiated aqueous environments. A limited number of irradiation corrosion and stress corrosion tests were performed. Chromium-molybdenum alloy steels and cast irons were also tested. These materials showed lower general corrosion but were susceptible to stress corrosion cracking when welded. 4 references, 4 tables

  6. Investigation for anti-stress corrosion cracking of SUS 304 stainless steel weldments

    The anti-stress corrosion cracking method by current density of cathodic protection was studied for stress corrosion cracking of SUS 304 stainless steel weldments in the environment of various MgCl2 boiling solution (wt%). Main results obtained are as follows: 1) Under the conditions below the critical current density of cathodic protection for anti-stress corrosion cracking, the latent time of crack initiation of weld heat affected zone occurs more rapidly than that of base metal because of the phenomenon of sensitizing and softening caused by weld heat cycles. 2) Under the constant current density of cathodic protection, the anti-stress corrosion cracking of weld heat affected zone can be controlled by critical concentration of MgCl2 solution. 3) The critical current density of cathodic protection of weld heat affected zone increases in proportion to concentration of MgCl2 solution. (Author)

  7. Corrosion of alloy steels in oil field fluids

    Laboratory and field tests have been conducted on two low alloy and two higher alloy steels at a range of brine salinities and sulfide contents typical of oil well production fluids. AISI types 4130 and 4340 show the same behavior in these fluids as mild steel. AISI type 410 stainless steel and 9% chromium - 1% molybdenum steel corrode at rates as great as that of mild steel at higher chloride or sulfide concentrations. Special corrosion inhibitors are required for higher alloy steels when they are exposed to these conditions

  8. Effect of Geobacter sulfurreducens on the microbial corrosion of mild steel, ferritic and austenitic stainless steels

    Mehanna, Maha [Laboratoire de Genie Chimique, CNRS - Universite de Toulouse, 5 rue Paulin Talabot, BP1301, 31029 Toulouse (France)], E-mail: mum34@psu.edu; Basseguy, Regine; Delia, Marie-Line; Bergel, Alain [Laboratoire de Genie Chimique, CNRS - Universite de Toulouse, 5 rue Paulin Talabot, BP1301, 31029 Toulouse (France)

    2009-11-15

    The influence of Geobacter sulfurreducens was tested on the anaerobic corrosion of four different steels: mild steel 1145, ferritic steel 403 and austenitic steels 304L and 316L. Within a few hours, the presence of cells induced a free potential (E{sub oc}) ennoblement around +0.3 V on 1145 mild steel, 403 ferritic steel and 304L austenitic steels and slightly less on 316L. The kinetics of E{sub oc} ennoblement depended on the amount of bacteria in the inoculum, but the final potential value depended essentially on the nature of the material. This effect was due to the capacity of G. sulfurreducens to create a direct cathodic reaction on steel surfaces, extracting the electrons directly from material. The presence of bacterial cells modified the corrosion features of mild steel and ferritic steel, so that corrosion attacks were gathered in determined zones of the surface. Local corrosion was significantly enhanced on ferritic steel. Potential ennoblement was not sufficient to induce corrosion on austenitic steels. In contrast G. sulfurreducens delayed the occurrence of pitting on 304L steel because of its capability to oxidize acetate at high potential values. The electrochemical behaviour of 304L steel was not affected by the concentration of soluble electron donor (acetate, 1-10 mM) or the amount of planktonic cells; it was directly linked to the biofilm coverage. After polarization pitting curves had been recorded, microscopic observations showed that pits propagated only in the surface zones where cell settlement was the densest. The study evidenced that Geobacter sulfurreducens can control the electrochemical behaviour of steels in complex ways that can lead to severe corrosion. As Geobacteraceae are ubiquitous species in sediments and soils they should now be considered as possible crucial actors in the microbial corrosion of buried equipment.

  9. Effect of Geobacter sulfurreducens on the microbial corrosion of mild steel, ferritic and austenitic stainless steels

    The influence of Geobacter sulfurreducens was tested on the anaerobic corrosion of four different steels: mild steel 1145, ferritic steel 403 and austenitic steels 304L and 316L. Within a few hours, the presence of cells induced a free potential (Eoc) ennoblement around +0.3 V on 1145 mild steel, 403 ferritic steel and 304L austenitic steels and slightly less on 316L. The kinetics of Eoc ennoblement depended on the amount of bacteria in the inoculum, but the final potential value depended essentially on the nature of the material. This effect was due to the capacity of G. sulfurreducens to create a direct cathodic reaction on steel surfaces, extracting the electrons directly from material. The presence of bacterial cells modified the corrosion features of mild steel and ferritic steel, so that corrosion attacks were gathered in determined zones of the surface. Local corrosion was significantly enhanced on ferritic steel. Potential ennoblement was not sufficient to induce corrosion on austenitic steels. In contrast G. sulfurreducens delayed the occurrence of pitting on 304L steel because of its capability to oxidize acetate at high potential values. The electrochemical behaviour of 304L steel was not affected by the concentration of soluble electron donor (acetate, 1-10 mM) or the amount of planktonic cells; it was directly linked to the biofilm coverage. After polarization pitting curves had been recorded, microscopic observations showed that pits propagated only in the surface zones where cell settlement was the densest. The study evidenced that Geobacter sulfurreducens can control the electrochemical behaviour of steels in complex ways that can lead to severe corrosion. As Geobacteraceae are ubiquitous species in sediments and soils they should now be considered as possible crucial actors in the microbial corrosion of buried equipment.

  10. Corrosion resistance properties of sintered duplex stainless steel

    L.A. Dobrzański; Z. Brytan; M. Actis Grande; M. Rosso

    2006-01-01

    Purpose: of this paper was to examine the corrosion resistance of duplex stainless steels using electrochemical methods in 1M NaCl solution. The influence of powder mixes preparation and cooling cycle after sintering on corrosion properties was evaluated.Design/methodology/approach: In presented study duplex stainless steels were obtained through powder metallurgy starting from austenitic, martensitic base powders by controlled addition of alloying elements, such as Cr, Ni, Mo and Cu. In the ...

  11. Corrosion under stress of AISI 304 steel in thiocyanate solutions

    Corrosion susceptibility under stress of AISI 304 steel sensitized in a sodium thiocyanate solution has been studied and results were compared with those obtained with solutions of thiosulfate and tetrathionate. Sensitized steel type 304 is highly susceptible to corrosion when under intergranular stress (IGSCC) in thiocyanate solutions but the aggressiveness of this anion is less than that of the other sulphur anions studied (thiosulfate and tetrathionate). This work has been partly carried out in the Chemistry Department. (Author)

  12. Corrosion behavior of plasma sprayed ceramic and metallic coatings on carbon steel in simulated seawater

    Highlights: • Plasma sprayed Ni60 coating can provide corrosion protect for the substrate. • Depositing ceramic coatings on metallic coating can improve the corrosion resistance. • The corrosion resistance of Al2O3 coating was better than that of ZrO2 coating. • The porosity had direct effect on the corrosion rate of the plasma sprayed coatings. • The top layer and the bond layer were treated as one coating in the EIS tests. - Abstract: Al2O3, ZrO2 and Ni60 coatings were produced on carbon steels by plasma spray. Ni60 was used as the bond coat in all the cases. The microstructure of these coatings was analyzed by scanning electron microscopy (SEM). The corrosion behavior of the plasma spray coated samples as well as uncoated samples was evaluated by open circuit potential (OCP) measurements, potentiodynamic polarization tests, and electrochemical impedance spectroscopy (EIS) in simulated seawater. The results showed that Ni60 coating protected carbon steels against the corrosion and plasma spraying ceramic powders on metallic coating improved the corrosion resistance of the coatings further. The corrosion resistance of the Al2O3 coating was superior to that of the ZrO2 coating due to the relatively few defects in Al2O3 coating

  13. Stress Corrosion Cracking of ferrito-pearlitic steel in aqueous environment containing dissolved CO2

    Vancostenoble, Alix; Duret-Thual, C.; Bosch, Cédric; Delafosse, David

    2014-01-01

    A confined aqueous environment is defined by a very low water-volume to exposed steel-area ratio. In such media containing dissolved CO2, siderite is formed and acts as a protective film. An addition of applied stress and/or environmental fluctuation can disturb the balance between the steel and this protective film, causing the fracture of the latter and leading to Stress Corrosion Cracking (SCC). The material studied is a cold drawn and rolled high strength steel composed of ferrite and sph...

  14. Effect of hydrogenase on the corrosion of mild steel

    Mehanna, Maha; Basséguy, Régine; Délia, Marie-Line; Bergel, Alain

    2007-01-01

    Losses due to corrosion are evaluated at 4% of the GDP of industrialised countries and biocorrosion may be responsible for 10% of these costs [1]. Whereas the general mechanism of anaerobic corrosion, involving iron sulphur deposits, seems now well agreed, the detailed mechanism is still unclear and the implication of hydrogenase is very controversial. The influence of a [Fe] hydrogenase from C. acetobutylicum on mild steel corrosion was studied using a galvanic cell and measuring the current...

  15. Monitoring Corrosion of Steel Bars in Reinforced Concrete Structures

    2014-01-01

    Corrosion of steel bars embedded in reinforced concrete (RC) structures reduces the service life and durability of structures causing early failure of structure, which costs significantly for inspection and maintenance of deteriorating structures. Hence, monitoring of reinforcement corrosion is of significant importance for preventing premature failure of structures. This paper attempts to present the importance of monitoring reinforcement corrosion and describes the different methods for eva...

  16. Electrochemical surface modification technique to impede mild steel corrosion using perfluorooctanoic acid

    Shubha H Natarj; Venkatesha T. Venkatarangaiah; ANANTHA N. SUBBA RAO

    2015-01-01

    The present work demonstrated that corrosion inhibition efficiency of electrochemically generated organic coat is remarkably more effective than self-assembled monolayer (SAM) generated by dip coating technique. Perfluorooctanoic acid (PFOA) is used to modify mild steel surface for effective protection. Infrared reflection absorption spectroscopy and contact angle measurements substantiate the modification of mild steel surface and its effect on surface hydrophobicity. A comparison between el...

  17. Spatial distribution of crystalline corrosion products formed during corrosion of stainless steel in concrete

    Serdar, Marijana

    2015-05-01

    © 2015 Elsevier Ltd All rights reserved. The mineralogy and spatial distribution of nano-crystalline corrosion products that form in the steel/concrete interface were characterized using synchrotron X-ray micro-diffraction (μ-XRD). Two types of low-nickel high-chromium reinforcing steels embedded into mortar and exposed to NaCl solution were investigated. Corrosion in the samples was confirmed by electrochemical impedance spectroscopy (EIS). μ-XRD revealed that goethite (α-FeOOH) and akaganeite (β-FeOOH) are the main iron oxide-hydroxides formed during the chloride-induced corrosion of stainless steel in concrete. Goethite is formed closer to the surface of the steel due to the presence of chromium in the steel, while akaganeite is formed further away from the surface due to the presence of chloride ions. Detailed microstructural analysis is shown and discussed on one sample of each type of steel.

  18. Steel corrosion in anoxic mediums with high chloride concentrations

    Carbon steels are widely used in contact with chloride containing mediums, however most of the literature reports corrosion problems in solutions in contact with air, for example, sea water. There are other applications where the steel is in contact with freshwater in the absence of oxygen as is the case with materials for nuclear repositories or in petroleum production. These mediums can have varied composition but their corrosivity is usually related to the concentration of chlorides. There are no systematic studies in the literature about the influence of high chloride concentrations on the speed of steel corrosion for carbon steels in the absence of oxygen. Some work has been done using Raman and XPS spectroscopy, but these techniques have been carried out ex situ in samples submitted to the action of high chloride concentrations. This results in the appearance of corrosion products on the metal surface due to the oxidation of the surface from exposure to air before and during the use of these techniques, generating confusing and uncertain data. The lack of reliable data is due to the difficulty of applying these techniques in situ under very low oxygen conditions (less than 10 ppb) without allowing any air into the system. Since there are no studies in the literature about the influence of high concentrations of chloride on the corrosion speed of carbon steels in the absence of oxygen, this work aims to generate experimental data to evaluate the influence of high concentrations of this anion on the corrosion speed of steel under anoxic conditions. The corrosivity of each solution was evaluated using electrochemical techniques such as corrosion potential, corrosion speed, anodic and cathodic polarization curves, cyclic voltammetries and electrochemical impedance spectroscopy to study the oxidation-reduction processes that occur with specific temperature, pH and chloride concentration conditions. Concentrated solutions of sodium chloride (50,000, 100,000 and 180

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

    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.

  20. A New Green Ionic Liquid-Based Corrosion Inhibitor for Steel in Acidic Environments.

    Atta, Ayman M; El-Mahdy, Gamal A; Al-Lohedan, Hamad A; Ezzat, Abdel Rahman O

    2015-01-01

    This work examines the use of new hydrophobic ionic liquid derivatives, namely octadecylammonium tosylate (ODA-TS) and oleylammonium tosylate (OA-TS) for corrosion protection of steel in 1 M hydrochloric acid solution. Their chemical structures were determined from NMR analyses. The surface activity characteristics of the prepared ODA-TS and OA-TS were evaluated from conductance, surface tension and contact angle measurements. The data indicate the presence of a double bond in the chemical structure of OA-TS modified its surface activity parameters. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) measurements, scanning electron microscope (SEM), Energy dispersive X-rays (EDX) analysis and contact angle measurements were utilized to investigate the corrosion protection performance of ODA-TS and OA-TS on steel in acidic solution. The OA-TS and ODA-TS compounds showed good protection performance in acidic chloride solution due to formation of an inhibitive film on the steel surface. PMID:26091073

  1. Phyllanthus muellerianus and C6H15NO3 synergistic effects on 0.5 M H2SO4-immersed steel-reinforced concrete: Implication for clean corrosion-protection of wind energy structures in industrial environment

    Okeniyi, Joshua Olusegun; Omotosho, Olugbenga Adeshola; Popoola, Abimbola Patricia Idowu; Loto, Cleophas Akintoye

    2016-07-01

    This paper investigates Phyllanthus muellerianus leaf-extract and C6H15NO3 (triethanolamine: TEA) synergistic effects on reinforcing-steel corrosion-inhibition and the compressive-strength of steel-reinforced concrete immersed in 0.5 M H2SO4. This is to assess suitability of the synergistic admixture usage for wind-energy steel-reinforced concrete structures designed for industrial environments. Steel-reinforced concrete specimens were admixed with individual and synergistic designs of Phyllanthus muellerianus leaf-extract and C6H15NO3 admixtures and immersed in the 0.5 M H2SO4. Electrochemical monitoring of corrosion potential, as per ASTM C876-91 R99, and corrosion current were obtained and statistically analysed, as per ASTM G16-95 R04, for modelling noise resistance. Post-immersion compressive-strength testing then followed, as per ASTM C39/C39M-03, for detailing the admixture effect on load-bearing strength of the steel-reinforced concrete specimens. Results showed that while individual Phyllanthus muellerianus leaf-extract concentrations exhibited better inhibition-efficiency performance than C6H15NO3, synergistic additions of C6H15NO3 to Phyllanthus muellerianus leaf-extract improved steel-rebar corrosion-inhibition. Thus, 6 g Phyllanthus muellerianus + 2 g C6H15NO3 synergistically improved inhibition-efficiency to η = 84.17%, from η = 55.28% by the optimal chemical or from η = 74.72% by the optimal plant-extract admixtures. The study also established that improved compressive strength of steel-reinforced concrete with acceptable inhibition of the steel-rebar corrosion could be attained through optimal combination of the Phyllanthus muellerianus leaf-extract and C6H15NO3 admixtures.

  2. Corrosion Protection under Thermal Insulation

    Sigbjørnsen, Karen

    2013-01-01

    Corrosion under insulation (CUI) is an extensive and costly problem for the petrochemical and chemical industry. Both good coatings to mitigate the problem and test methods to ensure the quality of these coatings are needed. In this thesis, four coatings; standard epoxy coating, epoxy phenolic coating, titanium modified inorganic copolymer (TMIC) and thermally sprayed aluminium (TSA), were tested for their ability to mitigate the problem. To simulate the CUI conditions, several test methods m...

  3. On the corrosion behavior of a ferritic 18 Cr-2 Mo-steel

    The investigations carried out with 18Cr-2Mo steel were aimed at its behaviour under pitting corrosion, crevice corrosion and stress corrosion cracking conditions. This was done in autoclave laboratory experiments and under experimental heat exchanger conditions in Rhine river water with a chloride content of max. 400 ppm. The test temperatures were 80, 100 and 1300C. Model heat exchangers were fabricated and operated to investigate the influence of filler materials and weld joints between the ferritic 18Cr-2Mo steel and a standard austenitic steel. The possibilities of fabricating tube sheers by applying a weld overaly and using explosive bonding were explored. 18Cr-2Mo steel has been shown to be suited for applications in cooling water which a chloride content of 400 ppm. No stress corrosion cracking occurs under such conditions. Tubes with a wall thickness up to 3 mm have sufficient toughness. Tube sheets can be made of boiler plate protected by an explosive cladding or a weld overlay of 18Cr-2Mo. A combination of Type 321 or 304 L and 18Cr-2Mo is possible. Provided 18Cr-2Mo is sufficiently resistant to the product to be cooled, it is an alternative to austenitic CrNi-(Mo) steels (e.g. AISI 304) when stress corrosion cracking is likely to occur. (orig.)

  4. Effect of Permeable Crystalline Material on Steel Reinforcement Corrosion of Concrete

    YU Jian-ying; WANG Gui-ming

    2004-01-01

    Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.

  5. Corrosion Behavior of Zirconium Treated Mild Steel with and Without Organic Coating: a Comparative Study

    Ghanbari, Alireza; Attar, Mohammadreza Mohammadzade

    2014-10-01

    In this study, the anti-corrosion performance of phosphated and zirconium treated mild steel (ZTMS) with and without organic coating was evaluated using AC and DC electrochemical techniques. The topography and morphology of the zirconium treated samples were studied using atomic force microscopy (AFM) and field emission scanning electron microscope (FE-SEM) respectively. The results revealed that the anti-corrosion performance of the phosphate layer was superior to the zirconium conversion layer without an organic coating due to very low thickness and porous nature of the ZTMS. Additionally, the corrosion behavior of the organic coated substrates was substantially different. It was found that the corrosion protection performance of the phosphate steel and ZTMS with an organic coating is in the same order.

  6. In situ Raman identification of stainless steels pitting corrosion films

    Raman spectroscopy is used for the in situ identification of the corrosion products grown during the pitting corrosion of stainless steels in presence of NaCl. To obtain a better approach of these complicated materials, binary alloys are first investigated, in which the alloying element is present in the same ratio as in steel. Here, results on Fe-10%Ni and Fe-18%Cr, AISI304 and AISI316 are presented and the respective parts played by chromium and molybdenum in the prevention of pitting corrosion are described. The outer product, ''colloidal'' green rust (GR) ,is particularly studied and a GR formula is proposed

  7. Corrosion of reinforcing steel in concrete - electrochemical laboratory experiments

    Steel bars with electric connections were embedded in prisms of six different concrete compositions. The test specimens were stored partly immersed into synthetic sea water or tap water over a period of about two years. Potential monitoring and polarisation experiments were used to estimate the corrosion rates of the steel. (author) 4 refs., 6 figs., 3 tabs

  8. Influence on corrosion resistance of superficial strain hardening of parts made of austenitic stainless steels

    Reactivity of strain hardened stainless steel 18-10 and 18-10 Mo in oxidizing media is very different at the surface and in the metal core. Surface corrosion or protection is very sensitive to superficial strain hardening resulting of mechanical treatments. Three physical phenomena are directly strain hardening dependent and have important consequences on corrosion resistance: 1) increase of diffusion rate of the different alloy elements, especially chromium; 2) residual superficial strain influence on stress corrosion and 3) structural transformation of metastable austenite

  9. In situ 3D monitoring of corrosion on carbon steel and ferritic stainless steel embedded in cement paste

    Itty, Pierre-Adrien

    2014-06-01

    In a X-ray microcomputed tomography study, active corrosion was induced by galvanostatically corroding steel embedded in cement paste. The results give insight into corrosion product build up, crack formation, leaching of products into the cracks and voids, and differences in morphology of corrosion attack in the case of carbon steel or stainless steel reinforcement. Carbon steel was homogeneously etched away with a homogeneous layer of corrosion products forming at the steel/cement paste interface. For ferritic stainless steel, pits were forming, concentrating the corrosion products locally, which led to more extensive damage on the cement paste cover. © 2014 Elsevier Ltd.

  10. Adsorption and corrosion inhibiting effect of riboflavin on Q235 mild steel corrosion in acidic environments

    Chidiebere, Maduabuchi A. [Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Rd, Shenyang 110016 (China); Electrochemistry and Materials Science Research Laboratory, Department of Chemistry, Federal University of Technology Owerri, PMB 1526 Owerri (Nigeria); Oguzie, Emeka E. [Electrochemistry and Materials Science Research Laboratory, Department of Chemistry, Federal University of Technology Owerri, PMB 1526 Owerri (Nigeria); Liu, Li [Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Rd, Shenyang 110016 (China); Li, Ying, E-mail: liying@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Rd, Shenyang 110016 (China); Wang, Fuhui [Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Rd, Shenyang 110016 (China)

    2015-04-15

    The inhibiting effect of Riboflavin (RF) on Q235 mild steel corrosion in 1 M HCl and 0.5 M H{sub 2}SO{sub 4} at 30 °C temperature was investigated using electrochemical techniques (electrochemical impedance spectroscopy and potentiodynamic polarization). The obtained results revealed that RF inhibited the corrosion reaction in both acidic solutions. Maximum inhibition efficiency values in 1 M HCl and 0.5 M H{sub 2}SO{sub 4} were 83.9% and 71.4%, respectively, obtained for 0.0012 M RF. Polarization data showed RF to be a mixed-type inhibitor, while EIS results revealed that the RF species adsorbed on the metal surface. The adsorption of RF followed Langmuir adsorption isotherm. Atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) studies confirmed the formation of a protective layer adsorbed on the steel surface. Quantum chemical calculations were used to correlate the inhibition ability of RF with its electronic structural parameters. - Highlights: • The inhibitory mechanism was influenced by the nature of acid anions. • RF has reasonable inhibition effect especially in 1 M HCl solution. • Polarization studies showed that RF functioned as a mixed type inhibitor. • Improved surface morphology was observed in the presence of RF.

  11. Adsorption and corrosion inhibiting effect of riboflavin on Q235 mild steel corrosion in acidic environments

    The inhibiting effect of Riboflavin (RF) on Q235 mild steel corrosion in 1 M HCl and 0.5 M H2SO4 at 30 °C temperature was investigated using electrochemical techniques (electrochemical impedance spectroscopy and potentiodynamic polarization). The obtained results revealed that RF inhibited the corrosion reaction in both acidic solutions. Maximum inhibition efficiency values in 1 M HCl and 0.5 M H2SO4 were 83.9% and 71.4%, respectively, obtained for 0.0012 M RF. Polarization data showed RF to be a mixed-type inhibitor, while EIS results revealed that the RF species adsorbed on the metal surface. The adsorption of RF followed Langmuir adsorption isotherm. Atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) studies confirmed the formation of a protective layer adsorbed on the steel surface. Quantum chemical calculations were used to correlate the inhibition ability of RF with its electronic structural parameters. - Highlights: • The inhibitory mechanism was influenced by the nature of acid anions. • RF has reasonable inhibition effect especially in 1 M HCl solution. • Polarization studies showed that RF functioned as a mixed type inhibitor. • Improved surface morphology was observed in the presence of RF

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

    Hong-Bok Choe; Han-Seung Lee; Jun-Ho Shin

    2014-01-01

    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 ...

  13. Microbially influenced corrosion of stainless steels in nuclear power plants

    Sinha, U.P.; Wolfram, J.H.; Rogers, R.D.

    1990-01-01

    This paper reviews the components, causative agents, corrosion sites, and potential failure modes of stainless steel components susceptible to microbially influenced corrosion (MIC). The stainless steel components susceptible to MIC are located in the reactor coolant, emergency, and reactor auxiliary systems, and in many plants, in the feedwater train and condenser. The authors assessed the areas of most high occurrence of corrosion and found the sites most susceptible to MIC to the heat-affected zones in the weldments of sensitized stainless steel. Pitting is the predominant MIC corrosion mechanisms, caused by sulfur reducing bacteria (SRB). Also discussed is the current status of the diagnostic, preventive, and mitigation techniques, including use of improved water chemistry, alternate materials, and improved thermomechanical treatments. 37 refs., 3 figs.

  14. Investigation of high temperature corrosion behavior on 304L austenite stainless steel in corrosive environments

    In this work, 304L stainless steel samples were exposed at 700 °C for 10hrs in different corrosive environments; dry oxygen, molten salt, and molten salt + dry oxygen. The corrosion behavior of samples was analyzed using weight change measurement technique, optical microscope (OM) and Scanning Electron Microscope (SEM) equipped with Energy Dispersive X-ray (EDX). The existence phases of corroded sample were determined using X-ray Diffraction (XRD). The lowest corrosion rate was recorded in dry oxygen while the highest was in molten salt + dry oxygen environments with the value of 0.0062 mg/cm2 and −13.5225 mg/cm2 respectively. The surface morphology of sample in presence of salt mixture showed scale spallation. Oxide scales of Fe3O4, Fe2O3 were the main phases developed and detected by XRD technique. Cr2O3 was not developed in every sample as protective layers but chromate-rich oxide was developed. The cross-section analysis found the oxide scales were in porous, thick and non-adherent that would not an effective barrier to prevent from further degradation of alloy. EDX analysis also showed the Cr-element was low compared to Fe-element at the oxide scale region

  15. Experimental and theoretical studies of thiazoles as corrosion inhibitors for mild steel in sulphuric acid solution

    Graphical abstract: The inhibition effect of 2-amino-5-mercapto-1,3,4-thiadiazole and 2-mercaptothiazoline on mild steel corrosion in 1.0 M H2SO4 was studied using electrochemical techniques. The effects of the presence of extra NH2 group and N atom in 2A5MT on the ability to act as corrosion inhibitors were investigated by theoretical calculations. Highlights: → The inhibition effects of thiazoles on mild steel corrosion in 1.0 M H2SO4 were studied. → It was shown that both thiazole compounds act as excellent corrosion inhibitors for mild steel. → The high inhibition efficiency was attributed to the adsorption of the inhibitor molecules on the metal surface. → Langmuir adsorption isotherm exhibited the best fit to the experimental data. → Quantum chemical calculations show there is a correlation between inhibitive property and molecular parameters. - Abstract: The inhibition effects of 2-amino-5-mercapto-1,3,4-thiadiazole (2A5MT) and 2-mercaptothiazoline (2MT) on mild steel corrosion in 1.0 M H2SO4 were studied with potentiodynamic polarization, linear polarization resistance and electrochemical impedance spectroscopy techniques. It was shown that both 2A5MT and 2MT act as good corrosion inhibitors for mild steel protection. The high inhibition efficiencies were attributed to the simple blocking effect by adsorption of inhibitor molecules on the steel surface. The effects of the presence of extra NH2 group and N atom in 2A5MT on the ability to act as corrosion inhibitors were investigated by theoretical calculations.

  16. Corrosion fatigue of a superduplex stainless steel weldment

    Comer, Anthony John

    2004-01-01

    Superduplex stainless steels have superior mechanical and corrosion properties compared to austenitic stainless steels such as the grade 300 series. This is a result of a microstructure consisting of roughly equal percentages of austenite (y) and ferrite (a) and negligible inclusion content. As a result, super duplex stainless steels are increasingly being used in the offshore oil and gas industries. It is also envisaged that they will find application in the emergent renewable energy sec...

  17. Corrosion of carbon steel nuclear waste containers in marine sediment

    The report describes a study of the corrosion of carbon steel nuclear waste containers in deep ocean sediments, which had the objective of estimating the metal allowance needed to ensure that the containers were not breached by corrosion for 1000 years. It was concluded that under such disposal conditions carbon steel would not be subject to localised corrosion or hydrogen embrittlement, and therefore the study concentrated on evaluating the rate of general attack. This was carried out by developing a mechanistically based mathematical model which was formulated on the conservative assumption that the corrosion would be under activation control, and would not be impeded by the formation of corrosion product layers. This model predicted that an allowance of 33 mm would be required for a 1000 year life. (author)

  18. Corrosion properties of stainless steel coatings made by different methods of thermal spraying

    The corrosion protection ability of thermally sprayed stainless steel coatings in aggressive environments is considerably limited as compared to bulk materials of the same composition. The two main reasons for the decrease in corrosion resistance are the porosity in the coatings and the oxidation of elements, particularly chromium, during spraying process. The corrosion resistance and structure of stainless steel coatings, ANVAL 254 SMO, made by different methods of thermal spraying were evaluated in this work. The coatings were produced by atmospheric plasma spraying (APS), atmospheric plasma spraying using gas shielding around the plasma (APS/S), low pressure plasma spraying (LPPS), detonation gun spraying (DGS) and high velocity oxyfuel spraying (HVOF). Electrochemical methods were used for determining the corrosion protection ability of coatings in 3.5% NaCl-solution and in sulfur acid solution (pH 3 and 1). The structure and composition of coatings were studied by optical microscopy and scanning electron microscopy/energy dispersive analysator (SEM/EDS). The porosity of the coatings was determined by water impregnation method, optical microscopy and mercury porosimeter. The results showed that the best coating quality can be achieved by LPPS- and HVOF-coatings. Oxidation and porosity restrict the use of APS-coatings in corrosive environments. The oxidation can be avoided by using argon gas shield around the plasma flame during spraying. Due to porosity all studied coatings suffered crevice corrosion in chloride solution. Despite high Mo-alloying the best coatings reached only the corrosion resistance of AISI 316

  19. Formation of Surface Corrosion-Resistant Nanocrystalline Structures on Steel.

    Nykyforchyn, Hryhoriy; Kyryliv, Volodymyr; Maksymiv, Olha; Slobodyan, Zvenomyra; Tsyrulnyk, Oleksandr

    2016-12-01

    Engineering materials with nanocrystalline structure could be exploited under simultaneous action of mechanical loading and corrosion environments; therefore, their corrosion resistance is important. Surface nanocrystalline structure was generated on middle carbon steels by severe plastic deformation using the method of mechanical pulse friction treatment. This treatment additionally includes high temperature phase transformation and alloying. Using a complex of the corrosive, electrochemical and physical investigations, it was established that nanocrystalline structures can be characterized by lower or increased corrosion resistance in comparison with the reference material. It is caused by the action of two confronting factors: arising energy level and anticorrosive alloying of the surface layer. PMID:26831689

  20. Study on corrosion simulation device for marine structural steel

    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.

  1. Formation of Surface Corrosion-Resistant Nanocrystalline Structures on Steel

    Nykyforchyn, Hryhoriy; Kyryliv, Volodymyr; Maksymiv, Olha; Slobodyan, Zvenomyra; Tsyrulnyk, Oleksandr

    2016-02-01

    Engineering materials with nanocrystalline structure could be exploited under simultaneous action of mechanical loading and corrosion environments; therefore, their corrosion resistance is important. Surface nanocrystalline structure was generated on middle carbon steels by severe plastic deformation using the method of mechanical pulse friction treatment. This treatment additionally includes high temperature phase transformation and alloying. Using a complex of the corrosive, electrochemical and physical investigations, it was established that nanocrystalline structures can be characterized by lower or increased corrosion resistance in comparison with the reference material. It is caused by the action of two confronting factors: arising energy level and anticorrosive alloying of the surface layer.

  2. Investigation of Fecraly Coating on Corrosion Behaviour of Mild Steel

    Joseph B. AGBOOLA

    2009-07-01

    Full Text Available Steel has found wide application in hot rolling equipments in the steel industry and the oil rig structures in sea water. These equipments are frequently subjected to corrosive and temperature condition which causes severe damage to them, hence the need to develop steel suitable to withstand these conditions in terms of surface treatment. This research work investigates the effect of FeCrAlY coating on mild steel under high temperature and aggressive environment. Iron based coatings are used due to low cost among other properties such as good corrosion resistance, ease of machining and high ductility when compared to hard metals.Thermal spraying of the specimens was carried out using high velocity oxygen fuel (HVOF. Corrosion test was carried out on both coated and uncoated samples. All samples were subjected to the same high temperature treatment for oxidation test.

  3. Spatial distribution of crystalline corrosion products formed during corrosion of stainless steel in concrete

    The mineralogy and spatial distribution of nano-crystalline corrosion products that form in the steel/concrete interface were characterized using synchrotron X-ray micro-diffraction (μ-XRD). Two types of low-nickel high-chromium reinforcing steels embedded into mortar and exposed to NaCl solution were investigated. Corrosion in the samples was confirmed by electrochemical impedance spectroscopy (EIS). μ-XRD revealed that goethite (α-FeOOH) and akaganeite (β-FeOOH) are the main iron oxide–hydroxides formed during the chloride-induced corrosion of stainless steel in concrete. Goethite is formed closer to the surface of the steel due to the presence of chromium in the steel, while akaganeite is formed further away from the surface due to the presence of chloride ions. Detailed microstructural analysis is shown and discussed on one sample of each type of steel. - Highlights: • Synchrotron micro-diffraction used to map the distribution of crystalline phases. • Goethite and akaganeite are the main corrosion products during chloride induced corrosion in mortar. • Layers of goethite and akaganeite are negatively correlated. • EDS showed Cr present in corrosion products identified by SEM

  4. Corrosion and hydrogen permeation of A216 Grade WCA steel in hydrothermal magnesium-containing brines

    Corrosion rates determined at 1 month in 150/degree/C brine increased with magnesium concentration. The structure of the corrosion product, as determined by x-ray diffraction, depended upon the magnesium concentration. In brines with less than 10,000 ppM magnesium, the primary corrosion product had a spinel structure characteristic of magnetite or magnesioferrite. In brines containing magnesium concentrations greater than 20,000 ppM, the primary corrosion product had the amakinite structure characteristic of a complex iron-magnesium hydroxide. The high corrosion rates observed in brines containing high magnesium concentrations suggest that the corrosion products having the amakinite structure is less protective than corrosion products having the spinel structure. Corrosion rates in high-magnesium (inclusion) brine determined over a 6-month test duration were essentially constant. Hydrogen permeation rates observed in exposing mild steel to high-Mg/sup 2/plus// brine at 150/degree/C could be potentially damaging to a mild steel waste package container. The rate of hydrogen permeation was proportional to the brine flow rate in the autoclave. Thiourea additions to the brine increased the hydrogen permeation rate; sulfate and bromide ion additions did not. The maximum gaseous hydrogen pressure attainable is not known (based on 3Fe /plus/ 4H2O /plus/ Fe(sub 3)O /plus/ 4H2, would be /approximately/900 atmospheres), and the dependence of permeation rate on temperature is not known. 8 refs., 13 figs., 3 tabs

  5. Rusting Evolution of MnCuP Weathering Steel Submitted to Simulated Industrial Atmospheric Corrosion

    Hao, Long; Zhang, Sixun; Dong, Junhua; Ke, Wei

    2012-05-01

    The rusting evolution of MnCuP weathering steel in a simulated industrial atmosphere as a function of corrosion duration was investigated by corrosion weight gain, scanning electron microscopy, X-ray diffraction, and electrochemical methods. The results indicate that the corrosion kinetics is related closely to the rust composition and electrochemical properties. The corrosion rate is higher during the first corrosion stage, and it is lower during the second corrosion stage. During the first corrosion stage, the rust layer is in low density, discontinuous, and loose, with a lower relative abundance of α-FeOOH. During the second corrosion stage, a compact and protective inner rust layer forms with a higher relative abundance of α-FeOOH, contributing to enhanced rust layer resistance. The rust initially enhances and then stabilizes the cathodic process, but the anodic process tends to be inhibited by the protective rust layer. Electrochemical impedance spectroscopy tests indicate that it is more scientific to evaluate the rust layer protective ability by charge transfer resistance.

  6. Corrosion resistance of high-strength modified 13% Cr steel

    Kimura, M.; Miyata, Y.; Yamane, Y.; Toyooka, T.; Nakano, Y.; Murase, F. [Kawasaki Steel Corp., Handa, Aichi (Japan)

    1999-08-01

    A new 13% Cr martensitic stainless steel (0.025% C-13% Cr-Ni-Mo) with excellent resistance to carbon dioxide (CO{sub 2}) corrosion and good resistance to sulfide stress cracking (SSC) was developed, and its application limits in oil and gas environments were clarified. The CO{sub 2} corrosion rate of the 13% Cr steels with Ni and Mo was < 0.3 mm/y at 180 C (356 F) in 20% sodium chloride (NaCl). It was less than that of the conventional 13% Cr steel (0.2% C-13% Cr). The corrosion rate of the steel slightly decreased with the increase in Mo and Ni content. The SSC resistance improved with the increase in Mo content. The critical partial pressure of hydrogen sulfide (H{sub 2}S) for the 2% Mo steel was > 0.005 MPa at pH 3.5. Effects of Ni and Cu on SSC were not distinctive for this kind of steel. These results depended upon hydrogen permeability. The critical H{sub 2}S partial pressure for the 110-grade steel was the same as that of the 95-grade steel at pH 4.5 and pH 3.0 and was slightly lower at pH values between 3.0 and 4.5. The new 13% Cr steel proved to have excellent properties in the sweet and slightly sour environments.

  7. Evaluation of stainless steels for their resistance to intergranular corrosion

    Austenitic stainless steels are being considered as structural materials for first wall/blanket systems in the international thermonuclear reactor (ITER). The uniform corrosion of stainless steels in water is well known and is not a critical issue limiting its application for the ITER design. The sensitivity of austenitic steels to intergranular corrosion (IGC) can be estimated rather accurately by means of calculation methods, considering structure and chemical composition of steel. There is a maximum permissible carbon content level, at which sensitization of stainless steel is eliminated: K=Creff-αCeff, where α-thermodynamic coefficient, Creff-effective chromium content (regarding molybdenum influence) and Ceff-effective carbon content (taking into account nickel and stabilizing elements). Corrosion tests for 16Cr11Ni3MoTi, 316L and 316LN steel specimens, irradiated up to 2 x 1022 n/cm2 fluence have proved the effectiveness of this calculation technique for determination of austenitic steels tendency to IGC. This method is directly applicable in austenitic stainless steel production and enables one to exclude complicated experiments on determination of stainless steel susceptibility to IGC. (orig.)

  8. Electrochemical synthesis and corrosion behavior of thin polyaniline film on mild steel, copper and aluminum

    Elkais Ali Ramadan

    2011-01-01

    Full Text Available The electrochemical synthesis of polyaniline (PANI on mild steel, aluminum and copper from the sodium benzoate solutions has been investigated. It has been shown that thin, highly adherent, polyaniline films on the investigated metals could be obtained by anodic oxidation with current densities in the range of 0.5 and 1.5 mA cm-2. The corrosion behavior of mild steel, aluminum and copper with polyaniline coating in 0.5 mol dm3 NaCl (pH 3 solutions, has been investigated by polarization technique. The corrosion current densities, porosity and protection efficiency was determined. It has been shown that polyaniline coating provided corrosion protection of all mentioned metals.

  9. Effect of Geobacter sulfurreducens on the microbial corrosion of mild steel, ferritic and austenitic stainless steels

    Mehanna, Maha; Basséguy, Régine; Délia, Marie-Line; Bergel, Alain

    2009-01-01

    The influence of Geobacter sulfurreducens was tested on the anaerobic corrosion of four different steels: mild steel 1145, ferritic steel 403 and austenitic steels 304L and 316L. Within a few hours, the presence of cells induced a free potential (Eoc) ennoblement around +0.3 V on 1145 mild steel, 403 ferritic steel and 304L austenitic steels and slightly less on 316L. The kinetics of Eoc ennoblement depended on the amount of bacteria in the inoculum, but the final potential value depended ess...

  10. Bacterial corrosion in marine sediments: influence of cathodic protection

    In order to protect offshore structures from marine corrosion, cathodic protection is widely applied via sacrificial anodes (for example zinc or aluminium) or impressed current. In aerated seawater, steel is considered to be protected when a potential of -8050 mV/Cu.CuSO4 is achieved. In many cases, however this potential must be lowered, due to the activity of microorganisms and more specially sulfate-reducing bacteria (SRB). SRB are obligate anaerobes using sulphate as electron acceptor with resultant production of sulphide. Some of them are also able to use hydrogen as energy source, causing cathodic depolarization of steel surfaces. An experiment was performed to analyze the relation between SRB activity and use of different cathodic potentials applied to mild steel samples in marine sediments. Analytical techniques employed included lipid bio-markers and electrochemical methods. Results indicated an evolution of the bacterial community structure both on the steel and in the sediment, as a function of time and potential. The results also show that cathodically produced hydrogen promotes the growth of SRB (author)

  11. Environmental factors affecting the corrosion behavior of reinforcing steel III. Measurement of pitting corrosion currents of steel in Ca(OH)2 solutions under natural corrosion conditions

    Using a simple electrolytic cell, the pitting corrosion current of reinforcing steel is measured in Ca(OH)2 solutions in presence of chloride and sulfate as aggressive ions. Pitting corrosion current starts to flow after an induction period which depends on the concentration of both the aggressive and the passivating anions. The pitting corrosion current densities reach steady-state values which depend also on the type and concentration of the corrosive and passivating anions. The corrosive action of the aggressive species decreased in the order: SO42- > Cl-. Corrosion of the steel is found to be governed by a single electron transfer reaction. Raising the temperature decreases the induction period associated with pit initiation and increases the corrosion current associated with pit propagation. From Arrhenius plots, the activation energies for both pit initiation and pit propagation in presence of chloride and sulfate ions are calculated.

  12. ANTICORROSION POTENTIAL OF HYDRALAZINE FOR CORROSION OF MILD STEEL IN 1M HYDROCHLORIC ACID SOLUTION

    B. M. Prasanna

    2015-05-01

    Full Text Available Anticorrosion potential of mild steel by Hydralazine as corrosion inhibitor for mild steel in 1M hydrochloric acid was investigated by chemical and electrochemical measurements at 303-333 K temperature. The maximum inhibition efficiency of inhibitor by Weight loss method is around 90%, Tafel polarization method is around 85%; electrochemical impedance spectroscopy measurement around 90% at 1250 ppm of Hydralazine in. The result shows that the inhibition efficiency increases with I 1M hydrochloric acid. Hydralazine acts as a mixed type inhibitor which inhibits the corrosion of mild steel due to the adsorption on metal surface. This adsorption system obeys the Langmuir adsorption isotherm.Activation parameters explains the effect of temperature with inhibition efficiency of inhibitor molecule.SEM images of inhibited mild steel strips shows a formation of passive protective film over the surface.

  13. Corrosion protection for silver reflectors

    Arendt, Paul N. (Los Alamos, NM); Scott, Marion L. (Los Alamos, NM)

    1991-12-31

    A method of protecting silver reflectors from damage caused by contact with gaseous substances which are often present in the atmosphere and a silver reflector which is so protected. The inventive method comprises at least partially coating a reflector with a metal oxide such as aluminum oxide to a thickness of 15 .ANG. or less.

  14. Poly(o-phenylenediamine) as an inhibitor of mild steel corrosion in HCl solution

    The inhibition properties of the electro-prepared P(o-phenylenediamine), P(oPD), on the corrosion rate of mild steel (MS) in HCl solutions have been investigated under different experimental conditions using weight loss and potentiodynamic polarization techniques. The data obtained from the two techniques are comparable and showed that the presence of P(oPD) in the acid solutions suppresses the corrosion rate of MS indicating that the polymer acts as corrosion inhibitor. The inhibition efficiency (IE%) of the polymer enhances with increasing its concentration and decreases with an increase in temperature. The inhibition occurs through adsorption and formation of barrier film on the metal surface which separates the metal from direct contact with the corrosive medium and hence protects the metal against the corrosion. Langmuir isotherm fits well with the experimental data. Thermodynamic parameters for both dissolution and adsorption processes were determined.

  15. Corrosion Behavior of Aluminum-Steel Weld-Brazing Joint

    Shi, Yu; Li, Jie; Zhang, Gang; Huang, Jiankang; Gu, Yufen

    2016-05-01

    Dissimilar metals of 1060 aluminum and galvanized steel were joined with a lap joint by pulsed double-electrode gas metal arc weld brazing with aluminum-magnesium and aluminum-silicon filler metals. The corrosion behavior of the weld joints was investigated with immersion corrosion and electrochemical corrosion tests, and the corrosion morphology of the joints was analyzed with scanning electron microscopy (SEM). Galvanic corrosion was found to occur when the samples were immersed in corrosive media, and the corrosion rate of joints was increased with increased heat input of the workpiece. Comparison of the corrosion properties of weld joints with different filler wires indicated that the corrosion rate of weld joints with aluminum-silicon filler wire was larger than that of weld joints with aluminum-magnesium filler wire. Results also showed that the zinc-rich zone of weld joints was prone to corrosion. The corrosion behavior of zinc-rich zone was analyzed with SEM equipped with an energy-dispersive x-ray spectroscopy analysis system based on the test results.

  16. Corrosion Behavior of Aluminum-Steel Weld-Brazing Joint

    Shi, Yu; Li, Jie; Zhang, Gang; Huang, Jiankang; Gu, Yufen

    2016-03-01

    Dissimilar metals of 1060 aluminum and galvanized steel were joined with a lap joint by pulsed double-electrode gas metal arc weld brazing with aluminum-magnesium and aluminum-silicon filler metals. The corrosion behavior of the weld joints was investigated with immersion corrosion and electrochemical corrosion tests, and the corrosion morphology of the joints was analyzed with scanning electron microscopy (SEM). Galvanic corrosion was found to occur when the samples were immersed in corrosive media, and the corrosion rate of joints was increased with increased heat input of the workpiece. Comparison of the corrosion properties of weld joints with different filler wires indicated that the corrosion rate of weld joints with aluminum-silicon filler wire was larger than that of weld joints with aluminum-magnesium filler wire. Results also showed that the zinc-rich zone of weld joints was prone to corrosion. The corrosion behavior of zinc-rich zone was analyzed with SEM equipped with an energy-dispersive x-ray spectroscopy analysis system based on the test results.

  17. Corrosion Products and Formation Mechanism During Initial Stage of Atmospheric Corrosion of Carbon Steel

    XIAO Kui; DONG Chao-fang; LI Xiao-gang; WANG Fu-ming

    2008-01-01

    The formation and development of corrosion products on carbon steel surface during the initial stage of atmospheric corrosion in a laboratory simulated environment have been studied by scanning electron microscopy (SEM)and Raman spectroscopy.The results showed that two different shapes of corrosion products,that is,ring and chain,were formed in the initial stage of corrosion.MnS clusters were found in the nuclei of corrosion products at the active local corrosion sites.The ring-shaped products were composed of lepidocrocite (γ-FeOOH) and maghemite(γ-Fe2 O3) transformed from lepidocrocite.The chain-type products were goethite (α-FeOOH).A formation mechanism of the corrosion products is proposed.

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

    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. PMID:25188842

  19. Stress corrosion cracking of stainless steel used in drill collars

    The present work, studies the stress corrosion cracking behavior in austenitic Fe-Cr-Mn-N stainless steel, in as received, solubilized and sensitized conditions, submitted to several chlorides environments. To evaluate the stress corrosion cracking susceptibility, double cantilever beam specimens, fatigue precracked, side grooved and wedge loaded were used. The environments employed were boiling solution of 45wt.% of MgCl2 at 154 deg. C and synthetic marine environment at ambient and boiling temperature. The susceptibility to stress corrosion cracking has been evaluated in terms of the corrosion stress intensity limit factor, KISCC, applying the fracture-mechanics concept. The results showed that only the specimens in the as received and sensitized conditions, were susceptible to the stress corrosion cracking effect in the boiling solution of 45wt.% of MgCl2 at 154 deg. C, and mean values of the stress corrosion intensity limit factor, KISCC, of 15MPam and 7.8MPam, respectively

  20. Corrosion Behaviors of Steel A3 Exposed to Thiobacillus Ferrooxidans

    Jianhua LIU; Xin LIANG; Songmei LI

    2008-01-01

    The corrosion behaviors of steel A3 in synergistic action of Thiobacillus ferrooxidans (T.f) and electrochemically accelerated corrosion were studied by electrochemical, microbiology and surface analysis methods. The open circuit potential (Eocp) and electrochemical impedance spectroscopy (EIS) of the steel A3 electrodes were measured in leathen culture medium without and with T.f (simply called T.f solution in the following paper)in immersion electrode way at the time of the 2nd, 5th, 10th, 20th and 30th days, respectively. It was found that Eocp of the electrode for immersion in leathen culture medium shifted negatively with the immersion time while that for immersion in T.f solutions shifted negatively, then positively and finally negatively. On the 20th day, the corrosion of steel A3 for immersion in culture medium was in pitting initiation stage while that for immersion in T.f solutions was in pitting growth stage. It was found that the corrosion of steel A3 was accelerated by T.f. The morphology of corrosion product of steel A3 immersion in T.f solutions observed through scanning electron microscopy (SEM) transformed from solid globules to tabular plates and to spongy globules and plates.

  1. Corrosion protection and finishing of automobiles

    finishing of automobiles is an important aspect. There have been considerable reductions of weight in automobiles by the use of composites components replacing heavy metallic components. Fenders previously based on metal have been replaced with plastic and painted with the same colour shade as of the metallic body, this has eps for proper adhesion of the paints on the plastic fender to avoid chipping off the paint form it. This paper discusses the necessary processes required for finishing of an automobile along with the corrosion protection measures. Automobiles contains a variety of engineering materials, engine main body fuel tanks connecting rods heat radiators and other mechanical parts are made from different types of engineering alloys having varying chemical compositions. Other parts like dashboard, front panel and other are made from composites. The main body made from cold roll ed steel having various contours 'c' it due to the different designs is the potential site for corrosion attack, The main body is exposed to the hostile environment through out its life period. An automobile is given a particular finish with a view to counter the hostile environments as they are not limited for plying in a limiting conditions and are taken to different weather conditions in one day thus facing severe stresses and strain. Thus it is essential that an automobile before rolling 'out of the assembly line should properly corrosion resistant and aesthetically pleasant also. Finishing for automobiles being very specialized, the main requirement being maximum durability with minimum numbers of coats baked, at the fastest possible schedule. High gloss and range of good eye catching colours being important to increase sales appeal. In the near past the car finishes were based on alkyd-amino resins baking materials and force drying lacquers, which have excellent appearance originally and maintain it on aging. The finishing system for the synthetic baking type may consist of

  2. Analysis of corrosion products of carbon steel in wet bentonite

    As a part of evaluation of the long-term durability for the overpack containers for high-level radioactive waste, we have conducted corrosion tests for carbon steel in wet bentonite, a candidate buffer material. The corrosion rates were evaluated by weight difference of carbon steel and corrosion products were analyzed by Fourier transform infrared spectroscopy (FT-IR) and colorimetry. At 40degC, the corrosion rate of carbon steel in wet bentonite was smaller than that in pure water. At 95degC, however, the corrosion rate in wet bentonite was much higher than that in pure water. This high corrosion rate in wet bentonite at 95degC was considered to result from evaporation of moisture in bentonite in contact with the metal. This evaporation led to dryness and then to shrinkage of the bentonite, which generated ununiform contact of the metal with bentonite. Probably, this ununiform contact promoted the local corrosion. The locally corroded parts of specimen in wet bentonite at 95degC were analyzed by Fourier transform infrared microspectroscopy (micro-FT-IR), and lepidocrocite γ-FeO(OH) was found as well as goethite α-FeO(OH). In wet bentonite at 95degC, hematite α-Fe2O3 was identified by means of colorimetry. (author)

  3. Corrosion of steel tanks in liquid nuclear wastes

    The objective of this work is to understand how solution chemistry would impact on the corrosion of waste storage steel tanks at the Hanford Site. Future tank waste operations are expected to process wastes that are more dilute with respect to some current corrosion inhibiting waste constituents. Assessment of corrosion damage and of the influence of exposure time and electrolyte composition, using simulated (non-radioactive) wastes, of the double-shell tank wall carbon steel alloys is being conducted in a statistically designed long-term immersion experiment. Corrosion rates at different times of immersion were determined using both weight-loss determinations and electrochemical impedance spectroscopy measurements. Localized corrosion susceptibility was assessed using short-term cyclic potentiodynamic polarization curves. The results presented in this paper correspond to electrochemical and weight-loss measurements of the immersed coupons during the first year of immersion from a two year immersion plan. A good correlation was obtained between electrochemical measurements, weight-loss determinations and visual observations. Very low general corrosion rates (-1) were estimated using EIS measurements, indicating that general corrosion rate of the steel in contact with liquid wastes would no be a cause of tank failure even for these out-of-chemistry limit wastes. (author)

  4. The Intergranular Corrosion of Mild Steel in CO2 + NaNO2 Solution

    Intergranular corrosion (IGC) is observed on mild steel surface when the steel is polarized to passive potential zone in CO2 + NaNO2 solution. The methods of potentiodynamic polarization, scanning electron microscope (SEM) and scanning tunneling microscope (STM) are applied to study the phenomenon. Intergranular corrosion mainly happens as the steel is polarized into the active–passive transition zone, and the width and depth of the corroded grain boundaries increase with potential in the zone. When the potential enters the passive zone, the depth of IGC shows only very slight change. The IGC is related to the segregation of the impurity elements Mn and Si at the grain boundaries. The occurrence of intergranular corrosion is influenced by the potential scanning rate and CO2 concentration in the solution. When the potential scanning rate is below 0.3 mV s−1 IGC phenomenon is observed. In saturated CO2 + NaNO2 solution no IGC is observed which may be attributed to the formation of FeCO3 layer on steel surface that protects the grain boundaries from corrosion. The observed IGC is due to the combined effect of CO2 and NaNO2 in solution. NO2− promotes passivation on the grain surface but CO2 induces corrosion at the grain boundaries

  5. Susceptibility to corrosion damage of pipeline steels under coating disbondments

    Guermazi, N.; Ibrahmi, A.; Hmidi, H.; Elleuch, K.; Ayedi, H.F. [Unite de Recherche de Chimie Industrielle et Materiaux, URCIM - ENIS, Sfax (Tunisia)

    2010-01-15

    This study provides an experimental investigation on the corrosion behaviour of three carbon steels used for pipeline application. The susceptibility of these materials to corrosion damage was analysed in order to simulate its service conditions particularly under disbonded coating. Monitoring of open-circuit potential (E{sub free}), polarization resistance (R{sub p}) and measuring of the weight loss during immersion time were used to evaluate the corrosion behaviour of the studied materials. All the corrosion experiments were performed in two aqueous solutions: natural seawater and synthetic one (3 wt% NaCl solution). The morphology of the corrosion products was examined by optical microscopy. The results obtained from electrochemical tests have shown different behaviour for the studied steels into the retained corrosive environments: more stable potentials (E{sub free}), higher R{sub p}-values with large fluctuations evolution were found in natural seawater. The gravimetric measurements have also shown a continuous variation of the weight loss throughout the exposure period in the sodium chloride solution. However, it seemed that a passive behaviour was observed in natural seawater. A little difference was observed between all the studied steels in terms of corrosion kinetics. The steel, having the little ferritic grain size, seems to be more resistant to corrosion damage. Qualitatively, a porous and non-adherent oxide film was observed on the corroded surface in the synthetic solution; while, the rust layer, which is formed in the natural seawater, has acted as a barrier of corrosion process. Finally, all the results obtained from both electrochemical tests and weight loss measurements were in reasonably good accordance. The important common point that can be concluded was that all the tested materials seem to be more suitable for natural seawater than 3 wt% NaCl solution. Also, they are not recommendable to be used in an environment where chloride attack is

  6. Materials corrosion and protection at high temperatures; Corrosion et protection des materiaux a haute temperature

    Balbaud, F.; Desgranges, Clara; Martinelli, Laure; Rouillard, Fabien [CEA-Saclay, DEN, DPC, SCCME, Laboratoire d' Etude de la Corrosion Non Aqueuse, 91191 Gif-sur-Yvette Cedex (France); Duhamel, Cecile [Mines ParisTech, Centre des materiaux UMR-CNRS 7633, BP 87, 91003 Evry Cedex (France); Marchetti, Loic; Perrin, Stephane [CEA, Laboratoire d' Etude de la Corrosion Aqueuse (France); Molins, Regine [Mines ParisTech, Direction de la Recherche, 60 Bvd Saint Michel, 75272 Paris Cedex 06 (France); Chevalier, S.; Heintz, O. [Laboratoire interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Univ. de Bourgogne, Dijon (France); David, N.; Fiorani, J.M.; Vilasi, M. [Institut Jean Lamour, UMR 7198, Univ. Henri Poincare Nancy-1 - CNRS, 54506 Vandoeuvre-les-Nancy (France); Wouters, Y.; Galerie, A. [SIMAP UMR CNRS 5266, Grenoble-INP/UJF, 1130 rue de la Piscine BP 75, 38402 Saint-Martin-d' Heres Cedex (France); Mangelinck, D. [IM2NP, UMR6242, CNRS, Univ. Paul Cezanne, Case 142, Faculte de Saint Jerome, 13397 Marseille Cedex 20 (France); Viguier, B.; Monceau, D. [Univ. de Toulouse, Institut Carnot CIRIMAT, INP-ENSIACET, 4 allee Emile Monso, BP 44362, 31030 Toulouse Cedex 4 (France); Soustelle, M. [Ecole nationale superieure des mines, Saint Etienne (France); Pijolat, M. [Centre Spin, Ecole des mines de Saint Etienne (France); Favergeon, J.; Brancherie, D.; Moulin, G.; Dawi, K. [Laboratoire Roberval, UTC (France); Wolski, K.; Barnier, V. [Centre SMS, EMSE, UMR 5146, LCG, Univ. de Lyon, 158 Cours Fauriel, 42023 Saint Etienne (France); Rebillat, F. [LCTS, Univ. de Bordeaux (France); Lavigne, O. [Onera, Dep. Materiaux et Structures Metalliques, BP 72, 29 av. de la Division Leclerc, 92322 Chatillon (France); Brossard, J.M. [Dep. energetique et procedes, Veolia Environnement Recherche et Innovation, Limay (France); Ropital, F. [IFP Energies Nouvelles, BP 3, 69360 Solaize (France); Mougin, J. [CEA-Liten, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France)

    2011-07-01

    This book was made from the lectures given in 2010 at the thematic school on 'materials corrosion and protection at high temperatures'. It gathers the contributions from scientists and engineers coming from various communities and presents a state-of-the-art of the scientific and technological developments concerning the behaviour of materials at high temperature, in aggressive environments and in various domains (aerospace, nuclear, energy valorization, and chemical industries). It supplies pedagogical tools to grasp high temperature corrosion thanks to the understanding of oxidation mechanisms. It proposes some protection solutions for materials and structures. Content: 1 - corrosion costs; macro-economical and metallurgical approach; 2 - basic concepts of thermo-chemistry; 3 - introduction to the Calphad (calculation of phase diagrams) method; 4 - use of the thermodynamic tool: application to pack-cementation; 5 - elements of crystallography and of real solids description; 6 - diffusion in solids; 7 - notions of mechanics inside crystals; 8 - high temperature corrosion: phenomena, models, simulations; 9 - pseudo-stationary regime in heterogeneous kinetics; 10 - nucleation, growth and kinetic models; 11 - test experiments in heterogeneous kinetics; 12 - mechanical aspects of metal/oxide systems; 13 - coupling phenomena in high temperature oxidation; 14 - other corrosion types; 15 - methods of oxidized surfaces analysis at micro- and nano-scales; 16 - use of SIMS in the study of high temperature corrosion of metals and alloys; 17 - oxidation of ceramics and of ceramic matrix composite materials; 18 - protective coatings against corrosion and oxidation; 19 - high temperature corrosion in the 4. generation of nuclear reactor systems; 20 - heat exchangers corrosion in municipal waste energy valorization facilities; 21 - high temperature corrosion in oil refining and petrochemistry; 22 - high temperature corrosion in new energies industry. (J.S.)

  7. Performance evaluation of pectin as ecofriendly corrosion inhibitor for X60 pipeline steel in acid medium: experimental and theoretical approaches.

    Umoren, Saviour A; Obot, Ime B; Madhankumar, A; Gasem, Zuhair M

    2015-06-25

    The corrosion inhibition effect of pectin (a biopolymer) for X60 pipeline steel in HCl medium was investigated using weight loss, electrochemical, water contact angle measurements, and scanning electron microscopy techniques. The results obtained show that pectin acts as a good corrosion inhibitor for X60 steel. Inhibition efficiency increased with increase in pectin concentration and temperature. Potentiodynamic polarization results reveal that pectin could be classified as a mixed-type corrosion inhibitor with predominant control of the cathodic reaction. The effective corrosion inhibition potential of pectin could be related to the adsorption of pectin molecules at the metal/solution interface which is found to accord with the Langmuir adsorption isotherm model and a protective film formation. Quantum chemical calculations provided insights into the active sites and reactivity parameters governing pectin activity as a good corrosion inhibitor for X60 steel. PMID:25839822

  8. Inhibition of carbon steel corrosion by 11-aminoundecanoic acid

    Saad Ghareba

    2015-12-01

    Full Text Available The current study reports results on the investigation of the possibility of using 11-aminoundecanoic acid (AA as an inhibitor of general corrosion of carbon steel (CS in HCl under a range of experimental conditions: inhibitor concentration, exposure time, electrolyte temperature and pH and CS surface roughness. It was found that AA acts as a mixed-type inhibitor, yielding maximum inhibition efficiency of 97 %. The adsorption of AA onto the CS surface was described by the Langmuir adsorption isotherm. The corresponding apparent Gibbs free energy of AA adsorption on CS at 295 K was calculated to be −30.2 kJ mol–1. The adsorption process was found to be driven by a positive change in entropy of the system. PM-IRRAS measurements revealed that the adsorbed AA layer is amorphous, which can be attributed to the repulsion between the neighboring positively charged amine groups and a high heterogeneity of the CS surface. It was also found that the AA provides very good corrosion protection of CS of various surface roughness, and over a prolonged time.

  9. Self-Healing Corrosion Protective Sol-Gel Coatings

    Abdolah Zadeh, M.

    2016-01-01

    Inspired by the state of the art and the recent advances in the field of self-healing corrosion protective coatings, the thesis entitled “Self-healing corrosion protective sol-gel coatings” addresses novel routes to self-healing corrosion protective sol-gel coatings via extrinsic and intrinsic heali

  10. Fabrication of superhydrophobic textured steel surface for anti-corrosion and tribological properties

    Zhang, Hongmei; Yang, Jin; Chen, Beibei; Liu, Can; Zhang, Mingsuo; Li, Changsheng

    2015-12-01

    We describe a simple and rapid method to fabricate superhydrophobic textured steel surface with excellent anti-corrosion and tribological properties on S45C steel substrate. The steel substrate was firstly ground using SiC sandpapers, and then polished using diamond paste to remove scratches. The polished steel was subsequently etched in a mixture of HF and H2O2 solution for 30 s at room temperature to obtain the textured steel surface with island-like protrusions, micro-pits, and nano-flakes. Meanwhile, to investigate the formation mechanism of the multiscale structures, the polished steel was immersed in a 3 wt% Nital solution for 5 s to observe the metallographic structures. The multiscale structures, along with low-surface-energy molecules, led to the steel surface that displayed superhydrophobicity with the contact angle of 158 ± 2° and the sliding angle of 3 ± 1°. The chemical stability and potentiodynamic polarization test indicated that the as-prepared superhydrophobic surface had excellent corrosion resistance that can provide effective protection for the steel substrate. The tribological test showed that the friction coefficient of the superhydrophobic surface maintained 0.11 within 6000 s and its superhydrophobicity had no obvious decrease after the abrasion test. The theoretical mechanism for the excellent anti-corrosion and tribological properties on the superhydrophobic surface were also analyzed respectively. The advantages of facile production, anti-corrosion, and tribological properties for the superhydrophobic steel surface make it to be a good candidate in practical applications.

  11. Effect of Cr content on the corrosion performance of low-Cr alloy steel in a CO2 environment

    Xu, Lining; Wang, Bei; Zhu, Jinyang; Li, Wei; Zheng, Ziyi

    2016-08-01

    Low-Cr alloy steel demonstrates lower corrosion rate than does C steel in a high-temperature and high-pressure CO2-containing environment. This study aimed to clarify the role of the Cr content in mitigating corrosion and reports the performance of 1%Cr, 2%Cr, 3%Cr, 4%Cr, 5%Cr, and 6.5%Cr steels. The results show that low-Cr alloy steel in CO2 at 80 °C and 0.8 MPa possesses spontaneous prepassivation characteristics when the Cr content is 3% or higher. Furthermore, the formation and peel-off of a prepassivation film on 3%Cr-6.5%Cr steels surfaces during polarization demonstrate that adequate amount of Cr in the steel substrate can cause protective layer. The main component of prepassivation film on 3%Cr steel is Cr(OH)3. Thus, the role of Cr is revealed. An adequate amount of Cr in the steel substrate causes the formation of protective Cr(OH)3 layer, which helps low-Cr steel to possess prepassivation characteristics. Prepassivation is the reason why low-Cr steel has a lower corrosion rate than C steel.

  12. Corrosion of mild steel, copper and brass in crude oil / seawater mixture

    PrabhaDevi, S.; Sawant, S.S.; Wagh, A.B.

    Mild steel, copper and brass coupons were introduced in natural seawater containing varying amount of crude oil. Mild steel showed higher rate of corrosion in seawater containing oil and lower corrosion rate in natural as well as artificial seawater...

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

    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.

  14. Recent Research and Development in Solving Atmospheric Corrosion Problems of Steel Industries in Japan

    A rust layer, so called 'protective' rust layer, on a weathering low-alloy steel has strong protective ability for atmospheric corrosion of the steel. We have recently found through a large number of spectroscopic studies including Moessbauer spectroscopy that the protective rust layer forms after long-term phase transformation. The phase and structure of the rust definitely control the protective ability of the rust layer. From this recent knowledge, some new technologies have been developed. One is the surface-treatment technique that provides a possibility for obtaining the protective rust layer in a relatively short period even in the severe environments such as in marine and chloride (de-icing salts) containing environments. Others are based on selection of effective alloying elements for steel materials. These are particularly important for application in areas where protective rust layer formation may be hindered or prevented. In this paper, we mention recent progress in research and development on rusting protection by rust for atmospheric corrosion of steels in Japan.

  15. Results of steel corrosion tests in flowing liquid Pb/Bi at 420-600 deg. C after 2000 h

    Corrosion tests were carried out on austenitic AISI 316L and 1.4970 steel and on MANET steel up to 2000 h of exposure to flowing (up to 2 m/s) Pb/Bi. The concentration of oxygen in the liquid alloy was controlled at 10-6 wt%. Specimens consisted of tube and rod sections in original state and after alloying of Al into the surface. After 2000 h of exposure at 420 and 550 deg. C the specimen surfaces were covered with an intact oxide layer which provided a good protection against corrosion attack of the liquid Pb/Bi alloy. At the same time corrosion attack at 600 deg. C was severe at the original AISI 316L steel specimens. The alloyed specimens containing FeAl on the surface of the alloyed layer still maintained an intact oxide layer with good corrosion protection up to 600 deg. C. (author)

  16. Corrosion inhibition of mild steel in HCL solution by pectin

    Highlights: • Pectin is an efficient inhibitor for mild steel corrosion in HCl. • Inhibition results from surface geometric blocking by chemisorbed species. • UV–visible data point to the formation of a complex between pectin and Fe2+ ions. - Abstract: This work describes the successful performance of pectin as an eco-friendly corrosion inhibitor for mild steel in HCl solution. The inhibition mechanism is discussed considering thermodynamics of adsorption and kinetics of the electrochemical reactions. Inhibition efficiency increases with temperature while the activation energy for the corrosion rate decreases with the addition of pectin. Pectin is a mixed-type inhibitor and the mode of inhibition results from the geometric blocking effect of chemisorbed inhibitive species at the metal surface. Spectroscopic analysis points to the formation of a complex between pectin and Fe2+ ions released during the corrosion reaction

  17. Corrosion inhibition of mild steel by aerobic biofilm

    Mild steel electrodes were incubated in phosphate-buffered basal salt solution (BSS) having two different aerobic bacteria, viz. Pseudomonas alcaligenes and Pseudomonas cichorii. In the medium containing P. cichorii, significant reduction in the corrosion rate was observed due to the surface reaction leading to the formation of corrosion inhibiting bacterial biofilm. With a view to understand the mechanism of microbially influenced corrosion/corrosion inhibition, electrochemical and biological experiments such as electrochemical impedance spectroscopy (EIS) measurements and biochemical analysis were made. The exposed surfaces were examined using scanning electron micrographs (SEM), energy dispersive spectroscopy (EDS) and electron spectroscopy for chemical analysis (ESCA). The scraped surface film was also examined using FT-IR spectroscopy. The results suggested that mild steel surface contained iron oxide-phosphate layer covered with bacteria and exo polymeric substance (EPS)/iron-EPS complex for P. cichorii and iron oxides and iron phosphate for P. alcaligenes

  18. Effect of Different Treatment on Corrosion Resistance of Sputtered Al Coating on Stainless Steel

    Fu, Guangyan; Qi, Zeyan; Su, Yong; Liu, Qun; Guo, Xingxing

    2014-12-01

    Aluminum coating on 1Cr18Ni9Ti stainless steel was prepared by magnetron sputtering method. The specimens were treated with pre-oxidation (PO) or vacuum diffusion annealing (VA). Hot corrosion resistance of the coatings beneath the deposits of Na2SO4 at 1050 °C was investigated. Corrosion products were analyzed by XRD and SEM. Results show that the presence of coating could improve the corrosion resistance of stainless steel. FeAl phase appeared after VA at 600 °C, which enhanced cohesive force between the coating and the substrate, and reduced the oxidation and sulfidation rate. PO treatment can protect the substrate more effectively than VA treatment for metastable Al2O3 formed during PO treatment can be translated to stable Al2O3 more quickly at high temperatures. The corrosion products of the two kinds of specimens with aluminum coating were both composed of Al2O3, a little amount of FeS and Fe2O3 after 24 h corrosion. Al2O3 was formed mainly in the coatings, FeS was mainly distributed in the interface between coating and substrate of the specimens, and a small amount of FeS was distributed in the substrate. Al2O3 film remained intact after 24 h corrosion, and kept its protective effect on the substrate.

  19. Oil field chemicals synergistic effects on the corrosion rate of L-80 steel in sea and formation waters

    Al Hashem, A.; Carew, J. [Petroleum Research and Studies Center, Kuwait Institute for Scientific Research, P.O. Box 24885, 13109 Safat Kuwait (Kuwait); Al-Borno, A. [Charter Coating Service (2000) Ltd., no 6, 4604, 13 Street N.E., Calgary, AB T2E 6P1 (Canada)

    2004-07-01

    The corrosion rate of tubular grade L-80 carbon steel under downhole conditions of a northern oil field of Kuwait was investigated. This was done using the injection seawater, formation water and a 50:50 mixture of both waters in the presence of commercially available corrosion inhibitor, scale inhibitor, and biocide products separately and in combination with each other. The main objective of this study was to investigate the effect of the corrosion inhibitor and its interaction with the scale inhibitor and the biocide, as seen in the corrosion rate of L80 carbon steel. This was done using the manufacturers' recommended dosage levels of the corrosion inhibitor, scale inhibitor and biocide. The corrosion rates were measured by linear polarization. Tests were conducted using the rotating cylinder electrode method with rotational speeds of 1000 and 2000 rpm at 80 deg. C. The seawater results indicated that the corrosion-scale inhibitor and biocide-scale inhibitor combinations provided the best protection at both rotation speeds. In formation water, the effects of rotation speed were more apparent with higher corrosion rates of L-80 carbon steel accompanying higher shear forces. In the 50: 50 mix waters and the formation water, the corrosion-scale inhibitors-biocide combination provided the best protection at both rotational speeds under downhole conditions of a northern oil field of Kuwait. (authors)

  20. Characterization of corrosion products formed on steels in the first months of atmospheric exposure

    Antunes Renato Altobelli; Costa Isolda; Faria Dalva Lúcia Araújo de

    2003-01-01

    The corrosion products of carbon steel and weathering steel exposed to three different types of atmospheres, at times ranging from one to three months, have been identified. The steels were exposed in an industrial site, an urban site (São Paulo City, Brazil), and a humid site. The effect of the steel type on the corrosion products formed in the early stages of atmospheric corrosion has been evaluated. The corrosion products formed at the various exposure locations were characterized by Raman...

  1. The behaviour of praseodymium 4-hydroxycinnamate as an inhibitor for carbon dioxide corrosion and oxygen corrosion of steel in NaCl solutions

    Highlights: •Praseodymium 4-hydroxycinnamate (Pr(4OHCin)3) highly effective corrosion inhibitor. •Mechanism of inhibition different in CO2-saturated solutions compared to aerated system. •In natural aerated solutions a continuous protective film forms on the steel surface. •In CO2-saturated solutions inhibiting deposits form at active corrosion sites. -- Abstract: Praseodymium 4-hydroxycinnamate (Pr(4OHCin)3) was investigated as a novel corrosion inhibitor for steel in NaCl solutions, and found to be effective at inhibiting corrosion in both CO2-containing and naturally-aerated systems. Surface analysis results suggest that the corrosion inhibition ability of Pr(4OHCin)3 in the naturally-aerated corrosion system could be attributed to the formation of a continuous protective film. For the CO2-containing system, the corrosion inhibition efficiency of Pr(4OHCin)3 was predominantly because of formation of protective inhibiting deposits at the active electrochemical corrosion sites, in addition to a thinner surface film deposit

  2. Development of Nb{sub 2}O{sub 5}|Cu composite as AISI 1020 steel thermal spray coating for protection against corrosion by soil in buried structures; Desenvolvimento e uso do composito de Nb{sub 2}O{sub 5}|Cu como revestimento aplicado por aspersao termica sobre o aco AISI 1020 para protecao contra a corrosao pelo solo em estruturas enterradas

    Regis Junior, Oscar [Universidade Tecnologica Federal do Parana, Ponta Grossa, PR (Brazil). Dept. de Mecanica; Silva, Jose Maurilio da; Portella, Kleber Franke [Instituto de Tecnologia para o Desenvolvimento, Curitiba, PR (Brazil). Dept. de Pesquisa em Engenharia Civil; Paredes, Ramon Sigifredo Cortes, E-mail: regis@utfpr.edu.br [Universidade Federal do Parana, Curitiba, PR (Brazil). Dept. de Mecanica

    2012-07-01

    An Nb{sub 2}O|Cu corrosion-resistant coating was developed and applied onto AISI 1020 steel substrate by Powder Flame Spray. A galvanostatic electrochemical technique was employed, with and without ohmic drop, in four different soils (two corrosively aggressive and two less aggressive). Behavior of coatings in different soils was compared using a cathodic hydrogen reduction reaction (equilibrium potential, overvoltage and exchange current density) focusing on the effect of ohmic drop. Results allow recommendation of Nb{sub 2}O{sub 5}|Cu composite for use in buried structure protection. (author)

  3. The methodology of determining the corrosion of steel structures

    S.D. Fedotov; A.V. Ulybin; N.N. Shabrov

    2013-01-01

    The problems of determining the corrosive wear of steel structures are considered. The results of applying ultrasonic method to determine the remaining profile of the structure are described. The main advantages and disadvantages of ultrasonic thickness meters comparing to mechanical devices are given. Low reliability of the method based on evaluating the thickness of the corrosion oxides is substantiated. The problems of determining the original section of the elements are outlined. The alg...

  4. Ni-W coatings electrodeposited on carbon steel: Chemical composition, mechanical properties and corrosion resistance

    Highlights: → Hard, ductile and adherent nanostructured Ni-W coatings on carbon steel. → New procedures for achieving deposits by current pulse techniques. → Current pulse frequency was the dominant factor to define coating characteristics. → Ni-W coatings protect the carbon steel from corrosion induced by sulphate anions. - Abstract: Hard, ductile and adherent nanostructured Ni-W coatings were electrodeposited on carbon steel from electrolyte solutions containing sodium tungstate, nickel sulfate and sodium citrate, using different current pulse programs. Current pulse frequency was the dominant factor to define chemical composition, grain size, thickness and hardness. According to the electrodeposition conditions the deposited coatings showed 15-30 at% W, the grain size ranged from 65 to 140 nm, and the hardness varied from 650 to 850 Hv. Tungsten carbide also present in the coating contributed to its hardness. The corrosion resistance of the Ni-W coated steel was tested by potentiodynamic polarization in a neutral medium containing sulphate ions. The Ni-W coating protected the carbon steel from localized corrosion induced by sulphate anions.

  5. Study on the Corrosion Inhibition Characteristics of Carbon Steel by Sodium Phosphate and Sodium Nitrite

    Sodium nitrite is widely used as one of the popular corrosion inhibitors for the protection of ferrous metal in closed cooling water system, such as a diesel engine and a chiller. The optimum treatment conditions are studied through laboratory tests using linear polarization resistance (LPR) technique. Corrosion rate of the carbon steel electrode could be maintained less than 2.5x10-3 mmpy in the test condition of 500 ppm as NO2-, 200 ppm as CT, 70 .deg. C and pH 6.8. The pH control is confirmed not to be an important factor in the protection of carbon steel by sodium nitrite inhibitor. The addition of tolyltriazole was needed for the protection of the copper alloy in the sodium nitrite treatment system

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

    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.

  7. Corrosion of 316L stainless steels MAVL wastes containers

    The long lived and medium activity wastes are conditioned or could be re-conditioned in primary drums of 316L stainless steels. In the framework of wastes storage, these drums will be placed in concrete containers; each containers would contain one or more drums. This document recalls global information on the corrosion of stainless steels, analyzes specific conditions bond to the drums conditioning in concrete containers and the nature of the wastes, and details the consequences on the possible risks of external and internal corrosion of the drums. (A.L.B.)

  8. Microbial corrosion of high alloy steels in natural sea water

    The paper deals with an investigation into regularities of settlement and potential impact of microbial forms on the corrosion of 12Kh18N10T stainless steel depending on its microstructure. It is shown that inhomogeneity of the morphorological composition and quantitative distribution of microorganisms on the surface of alloyed steels is caused by the selectivity of bacterial cells settlement on the substrate structural elements. The corrosion destruction at microscopic level primarily starts in the zones of microorganism concentration. 19 refs.; 3 figs.; 2 tabs

  9. Corrosion behaviour of some conventional stainless steels in electrolyzing process

    Amal NASSAR

    2015-12-01

    Full Text Available In this study, attempts were made to increase the amount of hydrogen generated from the water electrolysis process. Some conventional stainless steels (316; 409; 410 and 430 were used as anode and cathode in electrolysis process. Further study was carried out on the corrosion trend in all the investigated metals. It is observed that the electrode material can effect on the amount of hydrogen generate by electrolyzing process and metal composition of the stainless steels effects on the rate of corrosion.

  10. Testing corrosion rates on steel piping in geothermal district heating

    İnce, Umut; Toksoy, Macit; Güden, Mustafa

    2008-01-01

    The corrosion behavior of St-37 pipeline carbon steel (CS) in a geothermal district heating system was tested at two different fluid velocities. An experimental set-up, directly connected the the end of the transmission line of a geothermal well, was used to assess the corrosion of St-37 steel tensile test coupons prepared in accordance with ASTM E8 in geothermal fluid. The geothermal fluid entered the set-up with a relatively low velocity, 0.02 m/s, and then injected into the well with a rel...

  11. 21 CFR 178.3300 - Corrosion inhibitors used for steel or tinplate.

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Corrosion inhibitors used for steel or tinplate... AIDS, AND SANITIZERS Certain Adjuvants and Production Aids § 178.3300 Corrosion inhibitors used for steel or tinplate. Corrosion inhibitors may be safely used for steel or tinplate intended for use in,...

  12. Corrosion of a carbon steel in simulated liquid nuclear wastes

    This work is part of a collaboration agreement between CNEA (National Atomic Energy Commission of Argentina) and USDOE (Department of Energy of the United States of America), entitled 'Tank Corrosion Chemistry Cooperation', to study the corrosion behavior of carbon steel A537 class 1 in different simulated non-radioactive wastes in order to establish the safety concentration limits of the tank waste chemistry at Hanford site (Richland-US). Liquid high level nuclear wastes are stored in tanks made of carbon steel A537 (ASTM nomenclature) that were designed for a service life of 20 to 50 years. A thickness reduction of some tank walls, due to corrosion processes, was detected at Hanford site, beyond the existing predicted values. Two year long-term immersion tests were started using non radioactive simulated liquid nuclear waste solutions at 40 C degrees. This work extends throughout the first year of immersion. The simulated solutions consist basically in combinations of the 10 most corrosion significant chemical components: 5 main components (NaNO3, NaCl, NaF, NaNO2 and NaOH) at three concentration levels and 5 secondary components at two concentration levels. Measurements of the general corrosion rate with time were performed for carbon steel coupons, both immersed in the solutions and in the vapor phases, using weight loss and electrochemistry impedance spectroscopy techniques. Optic and scanning electron microscopy examination, analysis of U-bend samples and corrosion potential measurements, were also done. Localized corrosion susceptibility (pitting and crevice corrosion) was assessed in isolated short-term tests by means of cyclic potentiodynamic polarization curves. The effect of the simulated waste composition on the corrosion behavior of A537 steel was studied based on statistical analyses. The Surface Response Model could be successfully applied to the statistical analysis of the A537 steel corrosion in the studied solutions. General corrosion was not

  13. Nanocrystallization of aluminized surface of carbon steel for enhanced resistances to corrosion and corrosive wear

    Aluminizing is often used to improve steel's resistances to corrosion, oxidation and wear. This article reports our recent attempts to further improve aluminized carbon steel through surface nanocrystallization for higher resistances to corrosion and corrosive wear. The surface nanocrystallization was achieved using a process combining sandblasting and recovery heat treatment. The entire surface modification process includes dipping carbon steel specimens into a molten Al pool to form an Al coat, subsequent diffusion treatment at elevated temperature to form an aluminized layer, sandblasting to generate dislocation network or cells, and recovery treatment to turn the dislocation cells into nano-sized grains. The grain size of the nanocrystallized aluminized surface layer was in the range of 20-100 nm. Electrochemical properties, electron work function (EWF), and corrosive wear of the nanocrystalline alloyed surfaces were investigated. It was demonstrated that the nanocrystalline aluminized surface of carbon steel exhibited improved resistances to corrosion, wear and corrosive wear. The passive film developed on the nanocrystallized aluminized surface was also evaluated in terms of its mechanical properties and adherence to the substrate.

  14. Nanocrystallization of aluminized surface of carbon steel for enhanced resistances to corrosion and corrosive wear

    Chen, C. [Dept. of Materials Physical and Chemical, University of Science and Technology Beijing, Beijing 100083 (China); Dept. of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4 (Canada); Li, D.Y., E-mail: dongyang.li@ualberta.c [Dept. of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4 (Canada); Shang, C.J. [Dept. of Materials Physical and Chemical, University of Science and Technology Beijing, Beijing 100083 (China)

    2009-12-15

    Aluminizing is often used to improve steel's resistances to corrosion, oxidation and wear. This article reports our recent attempts to further improve aluminized carbon steel through surface nanocrystallization for higher resistances to corrosion and corrosive wear. The surface nanocrystallization was achieved using a process combining sandblasting and recovery heat treatment. The entire surface modification process includes dipping carbon steel specimens into a molten Al pool to form an Al coat, subsequent diffusion treatment at elevated temperature to form an aluminized layer, sandblasting to generate dislocation network or cells, and recovery treatment to turn the dislocation cells into nano-sized grains. The grain size of the nanocrystallized aluminized surface layer was in the range of 20-100 nm. Electrochemical properties, electron work function (EWF), and corrosive wear of the nanocrystalline alloyed surfaces were investigated. It was demonstrated that the nanocrystalline aluminized surface of carbon steel exhibited improved resistances to corrosion, wear and corrosive wear. The passive film developed on the nanocrystallized aluminized surface was also evaluated in terms of its mechanical properties and adherence to the substrate.

  15. Experimental studies of 2-pyridinecarbonitrile as corrosion inhibitor for mild steel in hydrochloric acid solution

    Highlights: • The corrosion effect of inhibitor was studied in 0.1 mol L−1 HCl on mild steel. • The inhibitor efficiency increases with increase in the concentration of inhibitor. • SEM micrographs showed that the inhibitor has a good protective film on the metal surface. - Abstract: The effect of 2-Pyridinecarbonitrile (2-PCN) was studied on mild steel (MS) corrosion in 0.1 mol L−1 HCl by electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and potentiodynamic polarization measurements. The surface morphologies of the MS were investigated in the inhibitor-free and in the presence of 10 mmol L−1 2-PCN containing corrosive media, at 120 h exposure period by scanning electron microscopy (SEM). The mechanism of adsorption was determined from the potential of zero charge (Epzc). 2-PCN adsorption on the MS surface obeyed the isotherm of Langmuir and the thermodynamic parameters Kads; ΔGads° were also calculated and discussed

  16. Characterization of Corrosion Products on Carbon Steel Exposed to Natural Weathering and to Accelerated Corrosion Tests

    Renato Altobelli Antunes

    2014-01-01

    Full Text Available The aim of this work was to compare the corrosion products formed on carbon steel plates submitted to atmospheric corrosion in urban and industrial atmospheres with those formed after accelerated corrosion tests. The corrosion products were characterized by X-ray diffraction, Mössbauer spectroscopy, and Raman spectroscopy. The specimens were exposed to natural weathering in both atmospheres for nine months. The morphologies of the corrosion products were evaluated using scanning electron microscopy. The main product found was lepidocrocite. Goethite and magnetite were also found on the corroded specimens but in lower concentrations. The results showed that the accelerated test based on the ASTM B117 procedure presented poor correlation with the atmospheric corrosion tests whereas an alternated fog/dry cycle combined with UV radiation exposure provided better correlation.

  17. Corrosion of connectors used in equipment protecting against falls from a height

    Jachowicz, Marcin

    2015-01-01

    Connectors are commonly found in personal equipment protecting against falls from a height. They are typically used outdoors and exposed to atmospheric factors, which can result in corrosion. This article presents the results of a study involving exposure of connectors to experimental corrosive media – neutral salt spray (NSS), acid salt spray (ASS), and seawater mist (for elements made of carbon steel and non-ferrous metals) – and to experimental conditions simulating the processes of pittin...

  18. Corrosion protection system for nuclear power plant

    A cathodic corrosion protection system for a nuclear power plant which employs an ion tank adjacent the main fresh water feed pipe leading to the steam generator to treat water from the main feed pipe and then return the treated water to the main feed pipe to form a corrosion protecting alkaline layer on surfaces of the main feed pipe and the secondary side of the steam generator. The ion tank receives measured amounts of hydrazine to render the water therein substantially conductive and contains ionizable metal anodes which release free metal ions as electric current flows between the anodes and a cathode connection on an ion tank outlet pipe near the main feed water pipe

  19. Corrosion fatigue behavior of carbon steel in drilling fluids

    Chaoyang, F.; Jiashen, Z. [Huazhong Univ. of Science and Technology, Wuhan (China)

    1998-08-01

    Corrosion fatigue of carbon steel (CS) in drilling fluids was studied using a self-made rotary bending corrosion fatigue testing apparatus under simulated drilling conditions. Mechanisms of the effects of cyclic stress, chloride (Cl{sup {minus}}), sulfide (S{sup 2{minus}}), and pH of drilling fluids on corrosion fatigue of CS as well as the inhibiting action of the imidazoline inhibitor and oxygen (O{sub 2}) scavenger sodium sulfite (Na{sub 2}SO{sub 3}) on corrosion fatigue were studied. Results showed Cl{sup {minus}} and S{sup 2{minus}} promoted corrosion fatigue crack initiation and growth. Fatigue life was lengthened after reducing subjected stress, increasing the pH of the drilling fluids, or adding the inhibitor and O{sub 2} scavenger.

  20. An evaluation of carbon steel corrosion under stagnant seawater conditions.

    Lee, Jason S; Ray, Richard I; Lemieux, Edward J; Falster, Alexander U; Little, Brenda J

    2004-01-01

    Corrosion of 1020 carbon steel coupons in natural seawater over a 1-year period was more aggressive under strictly anaerobic stagnant conditions than under aerobic stagnant conditions as measured by weight loss and instantaneous corrosion rate (polarization resistance). Under oxygenated conditions, a two-tiered oxide layer of lepidocrocite/goethite formed. The inner layer was extremely tenacious and resistant to acid cleaning. Under anaerobic conditions, the corrosion product was initially a non-tenacious sulphur-rich corrosion product, mackinawite, with enmeshed bacteria. As more sulphide was produced the mackinawite was transformed to pyrrhotite. In both aerobic and anaerobic exposures, corrosion was more aggressive on horizontally oriented coupons compared to vertically oriented samples. PMID:15621645

  1. Cathodic protection criteria for controlling microbially influenced corrosion in power plants

    Nekoksa, G. (Corrosion Failure Analysis and Control, San Ramon, CA (USA)); Gutherman, B. (Florida Power Corp., St. Petersburg, FL (USA))

    1991-05-01

    The main objective of this project was to evaluate galvanic corrosion on coupled samples and to determine cathodic protection criteria and effectiveness on four materials in an untreated seawater cooling system with microbially influenced corrosion. Hydrogen embrittlement of two cathodically protected high performance condenser tube materials was also evaluated. The long-term field testing was conducted at the intake structure of Florida Power Corporation's Crystal River Unit 3 Nuclear Power Plant. The test results indicate that Type 304L stainless steel can be galvanically corroded when coupled to Cu/Ni and fully cathodically protected when coupled to a carbon steel anode. Cathodic protection did protect carbon steel, but less than expected from the literature. The cathodic protection effectiveness on carbon steel was approximately 82% at {minus}1.01 V (SCE). To prevent hydrogen embrittlement, the tested titanium or ferritic stainless steel should not be polarized to more negative potentials than {minus}0.75 V (SCE). This report consists of a literature search, preliminary laboratory polarization testing, laboratory testing to determine microbial effects caused by an interruption of cathodic current, development of exposure racks for long-term electrochemical testing and analyses of corrosion, metallurgical, microbial and chemical data. 44 refs., 26 figs., 9 tabs.

  2. Corrosion resistance of zinc-magnesium coated steel

    A significant body of work exists in the literature concerning the corrosion behaviour of zinc-magnesium coated steel (ZMG), describing its enhanced corrosion resistance when compared to conventional zinc-coated steel. This paper begins with a review of the literature and identifies key themes in the reported mechanisms for the attractive properties of this material. This is followed by an experimental programme where ZMG was subjected to an automotive laboratory corrosion test using acidified NaCl solution. A 3-fold increase in time to red rust compared to conventional zinc coatings was measured. X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy were used to characterize the corrosion products formed. The corrosion products detected on ZMG included simonkolleite (Zn5Cl2(OH)8 . H2O), possibly modified by magnesium uptake, magnesium hydroxide (Mg(OH)2) and a hydroxy carbonate species. It is proposed that the oxygen reduction activity at the (zinc) cathodes is reduced by precipitation of alkali-resistant Mg(OH)2, which is gradually converted to more soluble hydroxy carbonates by uptake of atmospheric carbon dioxide. This lowers the surface pH sufficiently to allow thermodynamically for general precipitation of insoluble simonkolleite over the corroding surface thereby retarding the overall corrosion reactions, leaving only small traces of magnesium corrosion products behind. Such a mechanism is consistent with the experimental findings reported in the literature

  3. CO2 corrosion resistance of carbon steel in relation with microstructure changes

    The microstructural effects on the corrosion resistance of an API 5L X42 carbon steel in 0.5 M NaCl solution saturated with CO2 was investigated. Four microstructures were considered: banded (B), normalized (N), quenched and tempered (Q&T), and annealed (A). Electrochemical measurements (polarization curves and electrochemical impedance spectroscopy) were coupled with surface analyses (scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS)) to characterize the formation of the corrosion product layers. Electrochemical results revealed that corrosion resistance increased in the following order: B < N < Q&T < A. From the polarization curves it was shown that specifically, cathodic current densities were affected by microstructural changes. SEM images indicated that ferrite dissolved earlier than cementite and a thin layer of corrosion products was deposited on the steel surface. XPS analyses revealed that this layer was composed of a mixture of iron carbonate and non-dissolved cementite. It was also found that the quantity of FeCO3 content on the steel surface was greater for Q&T and A microstructures. These results, in agreement with the electrochemical data, indicate that the deposition mechanism of iron carbonate is closely related to the morphology of the non-dissolved cementite, determining the protective properties of the corrosion product layers. - Highlights: • The effect of change in microstructure on CO2 corrosion resistance was evaluated. • An API 5LX 42 carbon steel was immersed in a 0.5 M NaCl solution saturated with CO2. • Banded, normalized, quenched-tempered and annealed microstructures were considered. • Electrochemical measurements were coupled with surface analysis. • Morphology and distribution of undissolved Fe3C control corrosion kinetics

  4. CO{sub 2} corrosion resistance of carbon steel in relation with microstructure changes

    Ochoa, Nathalie, E-mail: nochoa@usb.ve [Departamento de Ciencia de los Materiales, Universidad Simón Bolívar, Aptdo., 89000, Caracas (Venezuela, Bolivarian Republic of); Vega, Carlos [Departamento de Ciencia de los Materiales, Universidad Simón Bolívar, Aptdo., 89000, Caracas (Venezuela, Bolivarian Republic of); Pébère, Nadine; Lacaze, Jacques [Université de Toulouse, CIRIMAT, UPS/INPT/CNRS, ENSIACET, 4 Allée Emile Monso, CS 44362, 31030 Toulouse Cedex 4 (France); Brito, Joaquín L. [Laboratorio de Físico-química de Superficies, Centro de Química, Instituto Venezolano de Investigaciones Cientificas (IVIC), Carretera Panamericana, Km 11, Altos de Pipe, Estado Miranda (Venezuela, Bolivarian Republic of)

    2015-04-15

    The microstructural effects on the corrosion resistance of an API 5L X42 carbon steel in 0.5 M NaCl solution saturated with CO{sub 2} was investigated. Four microstructures were considered: banded (B), normalized (N), quenched and tempered (Q&T), and annealed (A). Electrochemical measurements (polarization curves and electrochemical impedance spectroscopy) were coupled with surface analyses (scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS)) to characterize the formation of the corrosion product layers. Electrochemical results revealed that corrosion resistance increased in the following order: B < N < Q&T < A. From the polarization curves it was shown that specifically, cathodic current densities were affected by microstructural changes. SEM images indicated that ferrite dissolved earlier than cementite and a thin layer of corrosion products was deposited on the steel surface. XPS analyses revealed that this layer was composed of a mixture of iron carbonate and non-dissolved cementite. It was also found that the quantity of FeCO{sub 3} content on the steel surface was greater for Q&T and A microstructures. These results, in agreement with the electrochemical data, indicate that the deposition mechanism of iron carbonate is closely related to the morphology of the non-dissolved cementite, determining the protective properties of the corrosion product layers. - Highlights: • The effect of change in microstructure on CO{sub 2} corrosion resistance was evaluated. • An API 5LX 42 carbon steel was immersed in a 0.5 M NaCl solution saturated with CO{sub 2}. • Banded, normalized, quenched-tempered and annealed microstructures were considered. • Electrochemical measurements were coupled with surface analysis. • Morphology and distribution of undissolved Fe{sub 3}C control corrosion kinetics.

  5. Corrosion rate of carbon steel in NS tank water

    Neutron shield tank (NST) is an open tank 12.5 meters in height and 12 meters dia constructed around the research reactor. It is filled with water to (i) provide shielding from the neutron radiation, (ii) to remove the heat from the Pressure suppression system during LOCA and (iii) to act as a heat sink. NST is made of IS2062 carbon steel and it contains the stainless steel tanks, CS support structures, forged carbon steel gas cylinders, steel containment and its supports and emergency cooling down system condensers made of ASTM 350 grade LF2 carbon steel. All the equipments/systems located inside NST are painted with epoxy paint. NST is filled up 12 meters ie with 1200 m3 of water. The water chemistry parameters and microbiological parameters and corrosion rate of carbon steel materials in NST water at various water chemistry and various depths are discussed in the paper. (author)

  6. Morphology of protective film formed on steel in aqueous media inhibited with tetrazole

    Surface topography of low-carbon steel after its exposure in water solution of sodium sulfate containing tetrazole as inhibitor, is studied through the methods of screen-electron (SEM) and atom-power (APM) microscopy. The SEM data prove formation of the adsorption phase protection film on the surface of steel samples by their contact with corrosion aqueous media inhibited with tetrazole

  7. Boundary Element Method (BEM) Analysis for Galvanic Corrosion of Hot Dip Galvanized Steel Immersed in Seawater

    Xiao Tang; Yuzhi Zhanga; Meng Liu; Yan Li

    2009-01-01

    A numerical analysis of galvanic corrosion of hot-dip galvanized steel immersed in seawater was presented.The analysis was based on the boundary element methods (BEMs) coupled with Newton-Raphson iterative technique to treat the nonlinear boundary conditions, which were determined by the experimental polarization curves. Results showed that galvanic current density concentrates on the boundary of steel substrate and zinc coating, and the sacrificial protection of zinc coating to steel substrate results in overprotection of steel cathode. Not only oxygen reduction but also hydrogen reduction could occur as cathode reactions, which probably led up to the adsorption and absorption of hydrogen atoms. Flat galvanized steel tensile sample shows a brittle behavior similar to hydrogen embrittlement according to the SSRT (show strain rate test) in seawater.

  8. The corrosion of steels by hot sodium melts

    Considerable research has been performed by AEA Technology on the corrosion of steels by hot sodium melts containing sodium hydroxide and sodium oxide. This research has principally been in support of understanding the effects of sodium-water reactions on the internals of fast reactor steam generators. The results however have relevance to sodium fires. It has been determined that the rate of corrosion of steels by melts of pure NaOH can be significantly increased by the addition of Na2O. In the case of a sodium-water reaction jet created by a leak of steam into sodium, the composition of the jet varies from 100% sodium through to 100% steam, with a full range of concentrations of NaOH and Na2O, depending on axial and radial position. The temperature in the jet also varies with position, ranging from bulk sodium temperature on one boundary to expanded steam temperature on the other boundary, with internal temperatures ranging up to 1300 deg. C, depending on the local pre-reaction mole ratio of steam to sodium. In the case of sodium-water reaction jets, it has been possible to develop a model which predicts the composition of the reaction jet and then, using the data generated on the corrosivity of sodium melts, predict the rate of corrosion of a steel target in the path of the jet. In the case of a spray sodium fire, the sodium will initially contain a concentration of NaOH and the combustion process will generate Na2O. If there is sufficient humidity, conversion of some of the Na2O to NaOH will also occur. There is therefore the potential for aggressive mixtures of NaOH and Na2O to exist on the surface of the sodium droplets. It is therefore possible that the rate of corrosion of steels in the path of the spray may be higher than expected on the basis of assuming that only Na and Na2O were present. In the case of a pool sodium fire, potentially corrosive mixtures of NaOH and Na2O may be formed at some locations on the surface. This could lead to significant

  9. MICROBIAL CORROSION OF MILD AND MEDIUM CARBON STEELS

    J. E. O. OVRI

    2013-10-01

    Full Text Available The role of bacteria in the corrosion of mild and medium carbon steels is reported. The steels were exposed to anaerobic and aerobic, and fresh water (control environments. The corrosion rates were evaluated at intervals of seven days for a period of 42 days using weight loss and electrochemical methods. The corroded specimens were visually examined and majorities were found to have undergone general corrosion in the three environments (aerobic, anaerobic, and fresh water. The mild steel was found to corrode more than the medium carbon steel in anaerobic environment-mild steel: 6.43×10-4 mpy and -0.93 mV, due to limited available oxygen whilst it had -0.89 mV in aerobic and -0.77 mV in the fresh water. The medium carbon steel had -5.30×10-4 mpy and -0.91 mV in anaerobic: -0.84mV in aerobic and -0.74mV in freshwater.

  10. A liquid aluminum corrosion resistance surface on steel substrate

    The process of hot dipping pure aluminum on a steel substrate followed by oxidation was studied to form a surface layer of aluminum oxide resistant to the corrosion of aluminum melt. The thickness of the pure aluminum layer on the steel substrate is reduced with the increase in temperature and time in initial aluminizing, and the thickness of the aluminum layer does not increase with time at given temperature when identical temperature and complete wetting occur between liquid aluminum and the substrate surface. The thickness of the Fe-Al intermetallic layer on the steel base is increased with increasing bath temperature and time. Based on the experimental data and the mathematics model developed by the study, a maximum exists in the thickness of the Fe-Al intermetallic at certain dipping temperature. X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis reveals that the top portion of the steel substrate is composed of a thin layer of α-Al2O3, followed by a thinner layer of FeAl3, and then a much thicker one of Fe2Al5 on the steel base side. In addition, there is a carbon enrichment zone in diffusion front. The aluminum oxide surface formed on the steel substrate is in perfect condition after corrosion test in liquid aluminum at 750 deg. C for 240 h, showing extremely good resistance to aluminum melt corrosion

  11. Corrosion behaviour of carbon steel in the Tournemire clay

    Carbon steels are possible materials for the fabrication of nuclear waste containers for long term geological disposal in argillaceous environments. Experimental studies of the corrosion behaviour of such materials has been conducted in various conditions. Concerning the numerous laboratory experiments, these conditions (water and clay mixture or compacted clay) mainly concern the bentonite clay that would be used for the engineered barrier. On the opposite, only few in-situ experiments has been conducted directly in the local clay of the repository site (such as Boom clay, etc.). In order to better estimate the corrosion behaviour of carbon steels in natural clay site conditions, an experimental study has been conducted jointly by EDF and IRSN in the argillaceous French site of Tournemire. In this study, A42 carbon steel specimens have been exposed in 3 different zones of the Tournemire clay formation. The first type of environmental conditions concerns a zone where the clay has not been affected by the excavation (EDZ) of the main tunnel neither by the main fracture zone of the clay formation. The second and third ones are located in the EDZ of the tunnel. In the second zone, an additional aerated water flows from the tunnel, whereas it does not in the third place. Some carbon steel specimens have been extracted after several years of exposure to these conditions. The average corrosion rate has been measured by the weight loss technique and the pitting corrosion depth has been evaluated under an optical microscope. Corrosion products have also been characterised by scanning electron microscopy and X-ray diffraction technique. Results are then discussed regarding the surrounding environmental conditions. Calculations of the oxygen transport from the tunnel through the clay and of the clay re-saturation can explain, in a first approach, the corrosion behaviour of the carbon steel in the different tested zones. (authors)

  12. Mangrove tannins and their flavanoid monomers as alternative steel corrosion inhibitors in acidic medium

    Rahim, Afidah A. [School of Chemical Sciences, University Sains Malaysia, 11800 Penang (Malaysia)]. E-mail: afidah@usm.my; Rocca, E. [Laboratoire de Chimie du Solide Mineral, Universite Henri Poincare, Nancy I BP 239, 54506 Vandoeuvre Les Nancy (France); Steinmetz, J. [Laboratoire de Chimie du Solide Mineral, Universite Henri Poincare, Nancy I BP 239, 54506 Vandoeuvre Les Nancy (France); Kassim, M.J. [School of Chemical Sciences, University Sains Malaysia, 11800 Penang (Malaysia); Adnan, R. [School of Chemical Sciences, University Sains Malaysia, 11800 Penang (Malaysia); Sani Ibrahim, M. [School of Chemical Sciences, University Sains Malaysia, 11800 Penang (Malaysia)

    2007-02-15

    The inhibitive behaviour on steel of flavanoid monomers that constitute mangrove tannins namely catechin, epicatechin, epigallocatechin and epicatechingallate was investigated in an aerated HCl solution via electrochemical methods. The monomers were found to be mainly cathodic inhibitors and the inhibition efficiency was dependent on concentration. To explain the adsorptive behaviour of the molecules on the steel surface, a semiempirical approach involving quantum chemical calculations using HyperChem 6.0 was undertaken. The HOMO electronic density of the molecule was used to explain the inhibiting mechanism. The most probable adsorption centers were found in the vicinity of the phenolic groups. In a second part, the use of mangrove tannin, extracted from the mangrove barks as steel corrosion inhibitors in acidic media was investigated and its inhibitive efficiency was compared with that of commercial mimosa, quebracho and chestnut tannins. The inhibitive performance of mangrove tannins was comparable to the other tannins investigated, indicating their potential in corrosion protection.

  13. Mangrove tannins and their flavanoid monomers as alternative steel corrosion inhibitors in acidic medium

    The inhibitive behaviour on steel of flavanoid monomers that constitute mangrove tannins namely catechin, epicatechin, epigallocatechin and epicatechingallate was investigated in an aerated HCl solution via electrochemical methods. The monomers were found to be mainly cathodic inhibitors and the inhibition efficiency was dependent on concentration. To explain the adsorptive behaviour of the molecules on the steel surface, a semiempirical approach involving quantum chemical calculations using HyperChem 6.0 was undertaken. The HOMO electronic density of the molecule was used to explain the inhibiting mechanism. The most probable adsorption centers were found in the vicinity of the phenolic groups. In a second part, the use of mangrove tannin, extracted from the mangrove barks as steel corrosion inhibitors in acidic media was investigated and its inhibitive efficiency was compared with that of commercial mimosa, quebracho and chestnut tannins. The inhibitive performance of mangrove tannins was comparable to the other tannins investigated, indicating their potential in corrosion protection

  14. Contribution of acoustic emission to monitor the effect of phosphate based inhibitor on the corrosion behavior of steel reinforcement

    Nahali, Haifa [Laboratoire MATEIS CNRS UMR5511 (Equipe CorrIS), INSA-Lyon, Villeurbanne (France); Univ. de Tunis El Manar, Belvedere (Tunisia). Unite de Recherche ' ' Mecanique-Energetique' ' ; Dhouibi, Leila [Univ. de Tunis El Manar, Belvedere (Tunisia). Unite de Recherche ' ' Mecanique-Energetique' ' ; Idrissi, Hassane [Laboratoire MATEIS CNRS UMR5511 (Equipe CorrIS), INSA-Lyon, Villeurbanne (France)

    2014-11-01

    One of the most important causes of reinforced concrete structures deterioration is the corrosion of the reinforcement steel. This corrosion depends on the presence of aggressive agents such as chlorides in the surrounding medium. Numerous protection techniques have been employed to mitigate this corrosion. Among them, the use of corrosion inhibitors has been considered as one of the most effective solutions. In the present work, the influence of phosphate based inhibitor on the corrosion of reinforcing steels embedded in mortar, and immersed in sodium chloride solution, was investigated by acoustic emission technique. The monitoring of specimens shows that the phosphate based inhibitor addition in the mortar increase the threshold of chloride concentrations, causing the breakdown of steel passivation layer. Thus, the acoustic signatures of concrete fracture and of structure degradation during the corrosion of these specimens have been highlighted. Similarly, the mechanism of phosphate action in terms of preventing steel from corrosion in mortar specimens was analysed by characterization methods (SEM, XRD) of the steel-mortar interface.

  15. Contribution of acoustic emission to monitor the effect of phosphate based inhibitor on the corrosion behavior of steel reinforcement

    One of the most important causes of reinforced concrete structures deterioration is the corrosion of the reinforcement steel. This corrosion depends on the presence of aggressive agents such as chlorides in the surrounding medium. Numerous protection techniques have been employed to mitigate this corrosion. Among them, the use of corrosion inhibitors has been considered as one of the most effective solutions. In the present work, the influence of phosphate based inhibitor on the corrosion of reinforcing steels embedded in mortar, and immersed in sodium chloride solution, was investigated by acoustic emission technique. The monitoring of specimens shows that the phosphate based inhibitor addition in the mortar increase the threshold of chloride concentrations, causing the breakdown of steel passivation layer. Thus, the acoustic signatures of concrete fracture and of structure degradation during the corrosion of these specimens have been highlighted. Similarly, the mechanism of phosphate action in terms of preventing steel from corrosion in mortar specimens was analysed by characterization methods (SEM, XRD) of the steel-mortar interface.

  16. Case histories of microbiologically influenced corrosion of austenitic stainless steel weldments

    Microbiologically influenced corrosion (MIC) is initiated or accelerated by microorganisms and is currently recognized as a serious problem affecting the construction and operation of many industrial facilities, including nuclear power plants. The purpose of this paper is to review how biofouling and MIC can occur and discuss current mechanistic theories. A case history of MIC attack in power plants is examined with emphasis on the role of welding and heat treatment variables using laboratory electrochemical analyses. Although MIC can occur on a variety of alloys, pitting corrosion failures of austenitic stainless steels are often associated with weldments. MIC occurs as the result of a consortium of microorganisms colonizing on the metal surface and their variety (fungi, bacteria, algae, mold, and slimes) enables them to form support systems for cross feeding to enhance survival. The metabolic processes influence corrosion behaviour of materials by destroying protective coatings, producing a localized acid environment, creating corrosive deposits, or altering anodic and cathodic reactions. On stainless steels, biofilms destroy the passive oxide film on the surface of the steels and subject them to localized forms of corrosion. Many of the MIC failures in industry result in pitting to austenitic stainless steel weldments. Pitting primarily occurs in the weld metal, heat affected zones, and adjacent to the weld in the base metal. Depending on the conditions of the concentration cell created by the biofilm, either phase of the two-phase duplex stainless steel, austenite or delta ferrite, may be selectively attacked. Theories have been proposed about the mechanism of MIC on austenitic stainless steel and and a general understanding is that some function associated with the biofilm formation directly affects the electrochemical process

  17. Mitigating Localized Corrosion Using Thermally Sprayed Aluminum (TSA) Coatings on Welded 25% Cr Superduplex Stainless Steel

    Paul, S.; Lu, Q.; Harvey, M. D. F.

    2015-04-01

    Thermally sprayed aluminum (TSA) coating has been increasingly used for the protection of carbon steel offshore structures, topside equipment, and flowlines/pipelines exposed to both marine atmospheres and seawater immersion conditions. In this paper, the effectiveness of TSA coatings in preventing localized corrosion, such as pitting and crevice corrosion of 25% Cr superduplex stainless steel (SDSS) in subsea applications, has been investigated. Welded 25% Cr SDSS (coated and uncoated) with and without defects, and surfaces coated with epoxy paint were also examined. Pitting and crevice corrosion tests, on welded 25% Cr SDSS specimens with and without TSA/epoxy coatings, were conducted in recirculated, aerated, and synthetic seawater at 90 °C for 90 days. The tests were carried out at both the free corrosion potentials and an applied cathodic potential of -1100 mV saturated calomel electrode. The acidity (pH) of the test solution was monitored daily and adjusted to between pH 7.5 and 8.1, using dilute HCl solution or dilute NaOH, depending on the pH of the solution measured during the test. The test results demonstrated that TSA prevented pitting and crevice corrosion of 25% Cr SDSS in artificial seawater at 90 °C, even when 10-mm-diameter coating defect exposing the underlying steel was present.

  18. Stress corrosion cracking susceptibility of dissimilar stainless steels welded joints

    J. Łabanowski

    2007-01-01

    Full Text Available Purpose: The aim of the current study is to reveal the influence of welding conditions on structure and stresscorrosion cracking resistance of dissimilar stainless steels butt welded joints.Design/methodology/approach: Butt joints between duplex 2205 and austenitic 316L steels were performedwith the use of submerged arc welding (SAW method. The plates 15 mm in thickness were welded with heatinput in the range of 1.15 – 3.2 kJ/mm using duplex steel filler metal. Microstructure examinations and corrosiontests were carried out. Slow strain rate tests (SSRT were performed in inert (glycerin and aggressive (boiling35% MgCl2 solution environments.Findings: It was shown that place of the lowest resistance to stress corrosion cracking is heat affected zone atduplex steel side of dissimilar joins. That phenomenon was connected with undesirable structure of that zoneconsisted of great amount of coarse ferrite grains and acicular austenite precipitates. High welding inputs do notdeteriorate stress corrosion cracking resistance of welds.Research limitations/implications: High welding heat inputs should enhance the precipitation process ofintermetallic phases in the HAZ. It is necessary to continue the research to determine the relationship betweenwelding parameters, obtained structures, and corrosion resistance of dissimilar stainless steels welded joints.Practical implications: Application of more productive joining process for dissimilar welds like submerged arcwelding instead of currently employed gas metal arc welding (GMAW method will be profitable in terms ofreduction the welding costs.Originality/value: The stress corrosion cracking resistance of dissimilar stainless steel welded joints wasdetermined. The zone of the weaker resistance to stress corrosion cracking was pointed out.

  19. Trends in the automotive paint industry for corrosion protection

    Blandin, Nathalie; Brunat, William [PPG Industries France, 3 Z.A.E. Les Dix Muids, B.P. 89, F-59583 Marly (France); Neuhaus, Ralf [PPG Industries Lacke GmbH, Stackenbergstrasse 34, D-42329 Wuppertal (Germany); Sibille, Ettore [PPG Industries Italia, Via Serra11, I-15028 Quattordio (Italy)

    2004-07-01

    Since many years ED-paints are protecting car bodies against corrosion. Currently the automotive paint industry is faced with increasing demands of higher levels of corrosion protection and also requests to comply with new environmental regulations and economical pressures. Some key factors that contributed significantly towards the improvement of corrosion protection systems are: - New generations of lead free ED-paints; - Weldable organic thin film for corrosion protection, especially in box cavities and flange areas. The goal of this paper is to show how the various elements of the 'anti-corrosion package' interact. (authors)

  20. Some observations on phosphate based corrosion inhibitors in preventing carbon steel corrosion

    Among the various types of phosphonic acid based inhibitors assayed, namely HEDP, ATMP and a commercial corrosion inhibitor (code named Betz), it was found that Betz has the maximum amount of organic phosphate followed by HEDP and ATMP. The corrosion rate studies show that Betz gives the highest inhibition efficiency followed by HEDP and ATMP. This shows that organic phosphate plays a significant role in corrosion protection. However, it was observed that due to synergestic effect, HEDP in the presence of Zn2+ gave a better corrosion protection than Betz. The results are discussed in the light of available literature. (author)

  1. Sodium phthalamates as corrosion inhibitors for carbon steel in aqueous hydrochloric acid solution

    Highlights: → N-Alkyl-sodium phthalamates as corrosion inhibitors for industry in acidic medium. → Compounds behaved as mixed type inhibitors and followed Langmuir adsorption isotherm. → Efficiencies were proportional to aliphatic chain length and inhibitor concentration. → Iron complexes and chelates with phthalamates contributed to carbon steel protection. - Abstract: Three compounds of N-alkyl-sodium phthalamates were synthesized and tested as corrosion inhibitors for carbon steel in 0.5 M aqueous hydrochloric acid. Tests showed that inhibitor efficiencies were related to aliphatic chain length and dependent on concentration. N-1-n-tetradecyl-sodium phthalamate displayed moderate efficiency against uniform corrosion, 42-86% at 25 deg. C and 25-60% at 40 oC. Tests indicated that compounds behave as mixed type inhibitors where molecular adsorption on steel followed Langmuir isotherm, whereas thermodynamic suggested that a physisorption process occurred. XPS analysis confirmed film formation on surface, where Fe+2 complexes and Fe+2 chelates with phthalamates prevented steel from further corrosion.

  2. Anti-Corrosive Effect of Tridax Procumbens – Zn2+ System Controlling the Corrosion of Carbon Steel

    C. Kumar

    2014-03-01

    Full Text Available The corrosion inhibition efficiency (IE of an aqueous extract Tridax Procumbens(TP in controlling the corrosion of carbon steel aqueous medium containing 60 ppm of chloride ions in absence and presence of Zn2+ has been studied by weight loss method. The formulation consisting of 1 ml of Tridax Procumbens extract and 150 ppm of Zn2+ offers 96% inhibition efficiency. The synergistic effect exists between Tridax Procumbens and Zn2+ system. Polarization study shows that the Tridax Procumbens – Zn2+ system function as a cathodic inhibitor. AC impedance spectra reveal that a protective film formed on the surface. The Adsorption equilibrium exhibited better fit to Langmuir isotherm than Freundlich isotherm. FTIR spectra reveal that the protective film consists of Fe2+ -Tridax Procumbens and Zn(OH2.

  3. Cesium corrosion process in Fe–Cr steel

    A cesium corrosion out-pile test was performed to Fe–Cr steel in a simulated fuel pin environment. In order to specify the corrosion products, the corroded area was analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A cesium corrosion process in Fe–Cr steel was successfully developed proceeding from both experimental results and thermochemical consideration. The corroded area was mainly formed by Fe layer and Fe depleted oxidized layer. The Fe depleted oxidized layer was formed by Cr0.5Fe0.5 and Cr2O3. The presumed main corrosion reactions were 2Cr+2/3 O2→Cr2O3(ΔG650°C=-894.1kJ/mol) and Cr23C6+46Cs+46O2→23Cs2CrO4+6C(ΔG650°C=-25018.1kJ/mol). Factors of these reactions are chromium, carbon, oxygen and cesium. Therefore, cesium corrosion progression must be dependent on the chromium content, carbon content in the steel, the supply rate of oxygen and temperature which correlated with the diffusion rate of cesium and oxygen into the specimen

  4. Corrosion Resistance of High Performance Weathering Steel for Bridge Building Applications

    CHENAi—hua; XUJian—qiu; LIRan; LIHua—long

    2012-01-01

    The mechanical properties, corrosion resistance and microstructures of high performance steel (HPS) was investigated by tensile testing machine, Charpy V-Notch (CVN) testing machine, cyclic immersion corrosion tester, XRD, optical microscopy (OM), scanning electron microscopy (SEM), and electron probe micro-analyzer (EPMA). The results showed that significant differences existed in the tensile strength, yield strength and impact toughness between HPS and PCS. After 72 h cyclic immersion accelerated corrosion test, the inner rust layer on HPS was com- posed of a-FeOOH phase and denser than that on PCS that was a mixture of a-FeOOH and Fe3 04. The rust formed on HPS provides better protection and HPS has lower corrosion rates than PCS. Copper and chromium in HPS en- rich in the rust layer and enhance the compactness of the rust layer. Based on the results of the accelerated corrosion tests and rust layer analysis, the roles of Cu and Cr against corrosion are discussed, providing HPS with chemical specification which has been industrially successful to produce weathering steel for bridge structure.

  5. Microgalvanic corrosion of laser-welded HSLA steels

    Looi, Y.-M.

    2008-01-01

    Laser welding of galvanized high strength low alloy (HSLA) steels leads to the evaporation of zinc at the weld and the formation of a heat-affected-zone (HAZ). High heat input due to welding generates macro galvanic coupling between the weld and the parent metal as well as micro galvanic corrosion a

  6. Microbial corrosion of carbon steel by sulfate-reducing bacteria:

    Nielsen, Lars Vendelbo; Hilbert, Lisbeth Rischel

    1997-01-01

    Electrochemical measurements (EIS and DC-polarisation curves) have been conducted on carbon steel coupons exposed in SRB-active environments. Results from EIS measurements show that very large interfacial capacities are found in such systems, and consequently high capacitive currents are to be ex...... misleading conclusion that increasing corrosion rates are caused by cathodic depolarisation in SRB-active environments....

  7. Ambient temperature stress-corrosion cracking of sensitized stainless steels

    Stress-corrosion cracking of sensitized Type 304 steel in low temperature borated water has been observed. The probable role of low levels of chloride ions or sulfur-containing ions is described, including the relationship of the phenomenon to polythionic acid cracking. The mechanism of the sulfur-induced cracking and its usefulness as a test for sensitization are outlined

  8. Structural Characterization of Highly Corrosion-resistant Steel

    Lančok, Adriana; Kmjec, T.; Štefánik, M.; Sklenka, L.; Miglierini, M.

    2015-01-01

    Roč. 88, č. 4 (2015), s. 355-361. ISSN 0011-1643 R&D Projects: GA ČR(CZ) GA14-12449S Institutional support: RVO:61388980 Keywords : Mossbauer spectroscopy * corrosion -resistant steel * LC200 * CEMS Subject RIV: CA - Inorganic Chemistry Impact factor: 0.728, year: 2014

  9. Corrosion resistance of phosphated steels with plasma sprayed ceramic coatings

    Brožek, Vlastimil; Mastný, L.; Pokorný, P.

    Zagreb: Croatian Metallurgical Society (CMS), 2014 - (Mamuzić, I.). s. 401 ISBN N. [International Symposium of Croatian Metallurgical Society SHMD 2014/11./. 22.06.2014-26.06.2014, Šibenik] Institutional support: RVO:61389021 Keywords : steel phosphating * phosphate coatings * plasma spraying * ceramic coatings * corrosion resistance * bond strength of coatings Subject RIV: CA - Inorganic Chemistry

  10. Crude Oil Corrosion Fatigue of L485MB Pipeline Steel

    Gajdoš, Lubomír; Šperl, Martin; Bystrianský, J.

    2015-01-01

    Roč. 137, č. 5 (2015), 051401. ISSN 0094-9930 R&D Projects: GA TA ČR(CZ) TE02000162 Institutional support: RVO:68378297 Keywords : corrosion fatigue * crude oil * pipeline steel * S–N curve * separated water Subject RIV: JI - Composite Materials Impact factor: 0.357, year: 2014 http://pressurevesseltech.asmedigitalcollection.asme.org/article.aspx?articleID=2107675

  11. Corrosion resistance properties of sintered duplex stainless steel

    L.A. Dobrzański

    2006-09-01

    Full Text Available Purpose: of this paper was to examine the corrosion resistance of duplex stainless steels using electrochemical methods in 1M NaCl solution. The influence of powder mixes preparation and cooling cycle after sintering on corrosion properties was evaluated.Design/methodology/approach: In presented study duplex stainless steels were obtained through powder metallurgy starting from austenitic, martensitic base powders by controlled addition of alloying elements, such as Cr, Ni, Mo and Cu. In the studies behind the preparation of mixes, Schaeffler’s diagram was taken into consideration. Prepared mixes have been compacted at 800 MPa and sintered in a vacuum furnace with argon backfilling at 1260°C for 1 h. After sintering two different cooling cycles were applied: rapid cooling with an average cooling rate of 245 °C/min and slow cooling of 5 °C/min in argon atmosphere. Produced duplex stainless steels have been studied by scanning and optical microscopy and EDS chemical analysis of microstructure components. Corrosion properties have been studied through electrochemical methods in 1M NaCl water solutionFindings: According to achieved results, it was affirmed that applied sintering method as well as powder mixes preparation allows for manufacturing the sintered duplex steels with good corrosion properties which depends on austenite/ferrite ratio in the microstructure and elements partitioning between phases. Corrosion resistance of sintered stainless steels is strictly connected with the density and the pore morphology present in the microstructure too. The highest resistance to pitting corrosion in 1M NaCl solution was achieved for composition with approximate balance of ferrite and austenite in the microstructure.Research limitations/implications: According to the powders characteristic, the applied fast cooling rate seems to be a good compromise for corrosion properties and microstructures, nevertheless further tests should be carried out in

  12. Self-Healing Corrosion Protective Sol-Gel Coatings

    Abdolah Zadeh, M.

    2016-01-01

    Inspired by the state of the art and the recent advances in the field of self-healing corrosion protective coatings, the thesis entitled “Self-healing corrosion protective sol-gel coatings” addresses novel routes to self-healing corrosion protective sol-gel coatings via extrinsic and intrinsic healing approaches. The employed approaches aim at extending the service life of the coating and the underlying substrate by multiple damage closure/sealing and metal surface protection through incorpor...

  13. Molybdate Coatings for Protecting Aluminum Against Corrosion

    Calle, Luz Marina; MacDowell, Louis G.

    2005-01-01

    Conversion coatings that comprise mixtures of molybdates and several additives have been subjected to a variety of tests to evaluate their effectiveness in protecting aluminum and alloys of aluminum against corrosion. Molybdate conversion coatings are under consideration as replacements for chromate conversion coatings, which have been used for more than 70 years. The chromate coatings are highly effective in protecting aluminum and its alloys against corrosion but are also toxic and carcinogenic. Hexavalent molybdenum and, hence, molybdates containing hexavalent molybdenum, have received attention recently as replacements for chromates because molybdates mimic chromates in a variety of applications but exhibit significantly lower toxicity. The tests were performed on six proprietary formulations of molybdate conversion coatings, denoted formulations A through F, on panels of aluminum alloy 2024-T3. A bare alloy panel was also included in the tests. The tests included electrochemical impedance spectroscopy (EIS), measurements of corrosion potentials, scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS).

  14. Microstructure and corrosion behaviour of pulsed plasma-nitrided AISI H13 tool steel

    Basso, Rodrigo L.O. [Centro de Ciencias Exatas e Tecnologia, Universidade de Caxias do Sul, 95070-560 Caxias do Sul, RS (Brazil); Pastore, Heloise O. [Instituto de Quimica, Universidade Estadual de Campinas, 13084-862 Campinas, SP (Brazil); Schmidt, Vanessa [Centro de Ciencias Exatas e Tecnologia, Universidade de Caxias do Sul, 95070-560 Caxias do Sul, RS (Brazil); Baumvol, Israel J.R. [Centro de Ciencias Exatas e Tecnologia, Universidade de Caxias do Sul, 95070-560 Caxias do Sul, RS (Brazil); Instituto de Fisica, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, RS (Brazil); Abarca, Silvia A.C.; Souza, Fernando S. de; Spinelli, Almir [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis, SC (Brazil); Figueroa, Carlos A. [Centro de Ciencias Exatas e Tecnologia, Universidade de Caxias do Sul, 95070-560 Caxias do Sul, RS (Brazil); Giacomelli, Cristiano, E-mail: cgiacomelli@pq.cnpq.b [Centro de Ciencias Exatas e Tecnologia, Universidade de Caxias do Sul, 95070-560 Caxias do Sul, RS (Brazil)

    2010-09-15

    The effect of pulsed plasma nitriding temperature and time on the pitting corrosion behaviour of AISI H13 tool steel in 0.9% NaCl solutions was investigated by cyclic polarization. The pitting potential (E{sub pit}) was found to be dependent on the composition, microstructure and morphology of the surface layers, whose properties were determined by X-ray diffraction and scanning electron microscopy techniques. The best corrosion protection was observed for samples nitrided at 480 {sup o}C and 520 {sup o}C. Under such experimental conditions the E{sub pit}-values shifted up to 1.25 V in the positive direction.

  15. Microstructure and corrosion behaviour of pulsed plasma-nitrided AISI H13 tool steel

    The effect of pulsed plasma nitriding temperature and time on the pitting corrosion behaviour of AISI H13 tool steel in 0.9% NaCl solutions was investigated by cyclic polarization. The pitting potential (Epit) was found to be dependent on the composition, microstructure and morphology of the surface layers, whose properties were determined by X-ray diffraction and scanning electron microscopy techniques. The best corrosion protection was observed for samples nitrided at 480 oC and 520 oC. Under such experimental conditions the Epit-values shifted up to 1.25 V in the positive direction.

  16. Crack bridging in stress corrosion cracking of duplex stainless steels

    Wedge open loaded (WOL) specimens of age hardened Zeron 100 duplex stainless steel were tested in 3.5 wt % NaCl solution with cathodic polarizes applied at-900m V/SCE to investigate stress corrosion cracking mechanism in duplex stainless steel. The interaction between microstructure and mechanism of stress corrosion cracking was studied. Fracture mechanism was studied by using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The material was found cracked by ferrite cleavage, austenite tearing and austenite dissolution by environment. The ferrite cleavage took place along [100] planes and [112] twin habit planes. The austenite grains appear to act as crack bridging and crack arrester and failed by tearing and stress corrosion cracking. (author)

  17. Long-Term Underground Corrosion of Stainless Steels

    M. K. Adler Flitton; T. S. Yoder

    2007-03-01

    In 1970, the National Institute of Standards and Technology (NIST) implemented the most ambitious and comprehensive long-term corrosion behavior test to date for stainless steels in soil environments. Over thirty years later, one of the six test sites was targeted to research subsurface contamination and transport processes in the vadose and saturated zones. This research directly applies to environmental management operational corrosion issues and long term stewardship scientific needs for understanding the behavior of waste forms and their near-field contaminant transport of chemical and radiological contaminants at nuclear disposal sites. This paper briefly describes the ongoing research and the corrosion analysis results of the stainless steel plate specimens recovered from the partial recovery of the first test site.

  18. Effect of B-Mo-W Complex Inhibitor on Corrosion of Mild Steel in 55% LiBr Solution

    Li, Jielan; Liang, Chenghao; Huang, Naibao

    2015-11-01

    The inhibition effects of B-Mo-W complex inhibitor on corrosion of mild steel in 55% LiBr solution were investigated using weight-loss method, electrochemistry tests, SEM, EDX, and XRD. The ingredients of B-Mo-W complex inhibitor included organic phosphonic acid B, Na2MoO4, and Na2WO4. The results revealed that B-Mo-W complex inhibitor was capable of inhibiting the corrosion of mild steel in 55% LiBr solution, exhibiting high inhibition efficiencies around 97.7%. B-Mo-W complex inhibitor promoted the formation of a protective passive film composed of Fe, Mo, W, and O elements. The passive film decreased the corrosion rate, improved the electrochemistry performance, and enhanced anti-corrosion ability of mild steel.

  19. Inhibition of the corrosion of carbon steel in HCl solution by methionine and its derivatives

    Highlights: • The methionine derivatives were good corrosion inhibitors for 1045 carbon steel (CS). • The XPS indicated that the FMOC self-assembled on CS surface by chemisorption. • The Fukui surface distribution and the radial distribution function were used. - Abstract: The self-assembled films of methionine and its derivatives were prepared on a 1045 carbon steel (CS) surface. EIS and potentiodynamic measurements showed that these films could effectively protect CS against corrosion in 0.5 M HCl, with a maximal protection efficiency of 95.01% achieved by FMOC films. An XPS study confirmed that methionine and its derivatives could form films by chemical adsorption on CS. The inhibition mechanism was theoretically investigated through the quantum chemical calculation and dynamic simulation

  20. Corrosion of steels in sour gas environments

    This report presents a study on the effects of sour gas environments on steels. Emphasis is placed on alloys commonly used in the heavy water, sour gas and refining industries. In addition, 'high strength, low alloy' steels, known as 'oil country tubular goods', are included. Reference is made to the effects of hydrogen sulphide environments on austenitic steels and on certain specialty steels. Theories of hydrogen-related cracking mechanisms are outlined with emphasis placed on sulphide stress cracking and hydrogen induced cracking in carbon and low alloy steels. Methods of controlling sulphide stress cracking and hydrogen induced cracking are addressed separately. Case histories from the heavy water, refining, and sour gas industries are used to illustrate operating experience and failure mechanisms. Finally, recommendations, based largely on the author's industrial experience, are made with respect to quality assurance and inspection requirements for sour service components. Only published literature was surveyed. Abstracts were made of all references, reviewing the major sources in detail

  1. Corrosion testing type HP 9-4-20-steel

    Forged HP 9-4-20 steel exhibits a high yield strength [1240 MPa (180 ksi)], a high fracture toughness (K/sub Ic/) [120 MN/m/sup 3/2/ (110 ksi √in)], in good weldability. The alloy was studied to determine some of its corrosion and stress-corrosion characteristics, especially after welding. Potentiodynamic-polarization studies established that pitting of the steel was most severe when the chloride ion concentration was high and the pH of the solution was low. Higher potentials (approaching 1 V) caused increased corrosion rates also. Pitting of the welded samples was not preferential to any part of the weld and was uniform on both the base metal and weld. Dead-weight stress-corrosion tests demonstrated that welding did not increase susceptibility of the alloy to stress corrosion. The specimens failed in a ductile manner from the increased tensile load as the cross-sectional area was reduced by dissolution of the metal in the corrosive solution

  2. Corrosion of Ferritic-Martensitic steels in high temperature water: A literature Review

    Available literature concerning corrosion of high-chromium ferritic/martensitic steel in high temperature water as reviewed. The subjects considered are general corrosion, effect of irradiation on corrosion, environmentally assisted cracking (EAC) including stress corrosion cracking (SCC), corrosion fatigue and irradiation-assisted stress corrosion cracking (IASCC). In addition some investigations about radiation induced segregation (RIS). Are shown in order to know the compositional changes at grain boundaries of these alloys and their influence on corrosion properties. (Author)

  3. Microbial corrosion of P235GH steel under geological conditions

    Hajj, Hicham El; Abdelouas, Abdesselam; Grambow, Bernd; Martin, Christelle; Dion, Michel

    The role of microbial activity on the alteration of steel containers used for nuclear waste disposal is increasingly discussed. In this work we isolated and identified sulphate-reducing bacteria (SRB) in the Callovo-Oxfordian clay rock studied as a potential host rock formation for a repository for high-level and long-lived radioactive waste in France. Then, the effect of the SRB growth on the overpack steel corrosion was investigated. The corrosion rate of the steel coupons was high under biotic conditions (∼30 μm/year) in comparison to blank sterilized runs (∼14 μm/year). Culture experiments in compacted conditions with clay-stone cores and steel coupons under 120 bar, simulating deep geological conditions, gave results similar to those obtained in batch experiments (e.g. production of H 2S). This indicates the plausibility of SRB growth during the construction and operational phases of the repository and their survival at least temporarily after the disposal closure if water is available, which may cause fast corrosion of the steel containers under disposal conditions.

  4. Stress corrosion cracking of low steel weldments in LWR environments

    Results obtained at VTT in the ICG-EAC Group bolt-loaded WOL specimen testing round robin for pressure vessel steel weldments in simulated PWR primary water (typical of Loviisa VVER-440 power plant) are presented. Two low alloy type A508 C1.2 steels were tested; one steel had a very low S-content (0.002% S) and the other steel had normal medium S-content (0.008/0.009% S). The low sulphur steel did not show any indication of stress corrosion crack growth, while in one specimen of normal A508 C1.2 steel minor crack extension (less than 1 mm) was locally observed at the precrack tip in the HAZ of the weldment. Crack extension was explained by a water chemistry transient in one phase of the test and the phase of cracking could be related to this occurrence by detailed fractographic examination. Because of difficulties in locating exactly the precrack tip in the HAZ of the weldment, it was observed in the end of the test that precrack tips in various specimens were located either in the weld metal or in the HAZ or in some cases also very close to the fusion line. Thus, this study was also testing the stress corrosion cracking susceptibilities of the various zones of the weldments of low alloy pressure vessel steel A508 C1.2. Stress corrosion crack extension in small amounts was observed only in one HAZ specimen of the normal medium S-content steel

  5. Synthesis and Corrosion Inhibition Study of Benzothiazepine Derivatives on Mild Steel In Acid Medium

    T. Sasikala

    2016-05-01

    Full Text Available 2-ethoxy-4-(4-phenyl-2, 3-dihydro-1, 5-benzothiazepin-2-yl phenol (EPBTZ and 2-(4-methoxyphenyl-4-phenyl-2, 3-dihydro-1, 5-benzothiazepine (MPPBTZ were synthesized by the condensation reaction between o-aminothiophenol and chalcone. The synthesized benzothiazepines were characterized by FTIR spectra. Their corrosion inhibition property on mild steel in sulphuric acid medium was investigated by weight loss and electrochemical techniques. Scanning electron microscopic studies were employed to examine the surface morphology of the inhibited and uninhibited metal samples. The compound EPBTZ revealed good corrosion protection property than MPPBTZ at all the temperatures studied. Electrochemical studies showed that the inhibitors behave as mixed type inhibitor retarding both cathodic and anodic corrosion reaction by forming an adsorbed protective layer.

  6. Carbon exchange between steel and sodium as a corrosion phenomenon

    New analytical methods are applied to measure carbon in liquid sodium in the concentration range below 1 μg C/gNa. The carbon exchange between sodium and austenitic steel under decarburising conditions can be understood on the basis of the results of these analyses. The decarburisation of austenitic steel by sodium may cause a corrosive effect of the surface region of the materials. Some tests with the steel no. 1.4948 have demonstrated a reduction of its creep-rupture strength at 550deg C. The corrosion due to decarburisation proceeds slowly, specimens with a larger diameter were not affected, a significant reduction of the creep-rupture strength did not occur. (orig.)

  7. Niobium coatings on 316L stainless steel for improving corrosion resistance

    Niobium coatings were deposited onto 316L stainless steel substrates by ion-beam-assisted deposition. The coatings, deposited under 250 eV ion bombardment with [Ar+]/[Nb] ratios ranging from 0.68 to 0.8, were dense and showed no sign of pitting corrosion in a 3% NaCl solution. Also, based on the result of scratch tests, niobium coatings may act as sacrificial anodes and protect substrates. (orig.)

  8. Influence of Alloying Elements Corrosion Resistance of Cold on Mechanical Properties and Rolled C-Mn-Si TRIP Steels

    ZHANG Ling-yun; WU Di; LI Zhuang

    2012-01-01

    The rust layer plays an important role in the corrosion of steel in chlorinated environments. Salt spray, po- tentiodynamic polarization curve and tensile test were conducted in laboratory for the specimens after two-stage heat treatment. The influence of the alloying elements on mechanical properties and corrosion resistance of three kinds of steels was investigated by observing the microstructure and the morphologies of rust layer. The results show that the highest value (29%) of total elongation for steel A is obtained. The mechanical property of the specimen for steel C exhibits best strength ductility balance (21 384 MPa ·%) because of the presence of the multiphase microstructures after a two-stage heat treatment and the addition of the alloying elements. The corrosion products are known to be a complex mixture of Fe3O4 , Fe2O3 and α-FeOOH for steel C. The presence of the alloying elements results in the for mation of compact and dense rust layers in steel B and C. Passive film protects the substrate of TRIP (transformation induced plasticity) steel containing a complex mix of multiphase. Superior corrosion performance is exhibited for steel C with low alloying contents due to the enrichment of alloying elements within the rust layers.

  9. Mechanical properties and corrosion resistance of dissimilar stainless steel welds

    J. Łabanowski

    2007-01-01

    Full Text Available Purpose: The purpose of this paper is to determine the influence of welding on microstructure, mechanical properties, and stress corrosion cracking resistance of dissimilar stainless steels butt welded joints.Design/methodology/approach: Duplex 2205 and austenitic 316L steels were used. Butt joints of plates 15 mm in thickness were performed with the use of submerged arc welding (SAW method. The heat input was in the range of 1.15 – 3.2 kJ/mm. Various plates’ edge preparations were applied. Microstructure examinations were carried out. Mechanical properties were evaluated in tensile tests, bending tests and Charpy-V toughness tests. Susceptibility to stress corrosion cracking was determined with the use of slow strain rate tests (SSRT performed in inert (glycerin and aggressive (boiling 35% MgCl2 solution environments.Findings: All tested joints showed acceptable mechanical properties. Metallographic examinations did not indicate the excessive ferrite contents in heat affected zones (HAZ of the welds. It was shown that area of the lowest resistance to stress corrosion cracking is heat affected zone at duplex steel side of dissimilar joins. That phenomenon is connected with undesirable structure of that zone consisted of greater amounts of coarse ferrite grains and acicular austenite precipitates. High heat inputs do not deteriorate mechanical properties as well as stress corrosion cracking resistance of welds.Practical implications: All tested joints showed acceptable mechanical properties. Metallographic examinations did not indicate the excessive ferrite contents in heat affected zones (HAZ of the welds. It was shown that area of the lowest resistance to stress corrosion cracking is heat affected zone at duplex steel side of dissimilar joins. That phenomenon is connected with undesirable structure of that zone consisted of greater amounts of coarse ferrite grains and acicular austenite precipitates. High heat inputs do not deteriorate

  10. Corrosion behaviour of hot dip zinc and zinc-aluminium coatings on steel in seawater

    Yan Li

    2001-08-01

    A comparative investigation of hot dip Zn–25Al alloy, Zn–55Al–Si and Zn coatings on steel was performed with attention to their corrosion performance in seawater. The results of 2-year exposure testing of these at Zhoushan test site are reported here. In tidal and immersion environments, Zn–25Al alloy coating is several times more durable than zinc coating of double thickness. At long exposure times, corrosion rate for the Zn–25Al alloy coating remains indistinguishable from that for the Zn–55Al–Si coating of similar thickness in tidal zone, and is two to three times lower than the latter in immersion zone. The decrease in tensile strength suggested that galvanized and Zn–55Al–Si coated steel suffer intense pitting corrosion in immersion zone. The electrochemical tests showed that all these coatings provide cathodic protection to the substrate metal; the galvanic potentials are equal to – 1,050, – 1,025 and – 880 mV (SCE) for zinc, Zn–25Al alloy and Zn–55Al–Si coating, respectively, which are adequate to keep the steel inside the immunity region. It is believed that the superior performance of the Zn–25Al alloy coating is due to its optimal combination of the uniform corrosion resistance and pitting corrosion resistance. The inferior corrosion performance by comparison of the Zn coating mainly results from its larger dissolution rate, while the failure of the Zn–55Al–Si coating is probably related to its higher susceptibility to pitting corrosion in seawater.

  11. Long-term atmospheric corrosion of mild steel

    Research highlights: → Atmospheric corrosion rate stabilises after the first 4-6 years of exposure. → Great compaction of the rust layers in rural and urban atmospheres. → Corrosion (in rural and urban) deviates from common behaviour of bilogarithmic law. → Typical structures of lepidocrocite, goethite and akaganeite are identified. → Formation of hematite (industrial atmosphere) and ferrihydrite (marine atmosphere). - Abstract: A great deal of information is available on the atmospheric corrosion of mild steel in the short, mid and even long term, but studies of the structure and morphology of corrosion layers are less abundant and generally deal with those formed in just a few years. The present study assesses the structure and morphology of corrosion product layers formed on mild steel after 13 years of exposure in five Spanish atmospheres of different types: rural, urban, industrial and marine (mild and severe). The corrosion layers have been characterised by X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Long-term corrosion is seen to be more severe in the industrial and marine atmospheres, and less so in the rural and urban atmospheres. In all cases the corrosion rate is seen to decrease with exposure time, stabilising after the first 4-6 years of exposure. The most relevant aspects to be noted are (a) the great compaction of the rust layers formed in the rural and urban atmospheres, (b) the formation of hematite and ferrihydrite phases (not commonly found) in the industrial and marine atmospheres, respectively and (c) identification of the typical morphological structures of lepidocrocite (sandy crystals and flowery plates), goethite (cotton balls structures) and akaganeite (cotton balls structures and cigar-shaped crystals).

  12. Long-term atmospheric corrosion of mild steel

    Fuente, D. de la; Diaz, I.; Simancas, J.; Chico, B. [National Centre for Metallurgical Research (CENIM-CSIC), Avda. Gregorio del Amo, 8, 28040 Madrid (Spain); Morcillo, M., E-mail: morcillo@cenim.csic.e [National Centre for Metallurgical Research (CENIM-CSIC), Avda. Gregorio del Amo, 8, 28040 Madrid (Spain)

    2011-02-15

    Research highlights: {yields} Atmospheric corrosion rate stabilises after the first 4-6 years of exposure. {yields} Great compaction of the rust layers in rural and urban atmospheres. {yields} Corrosion (in rural and urban) deviates from common behaviour of bilogarithmic law. {yields} Typical structures of lepidocrocite, goethite and akaganeite are identified. {yields} Formation of hematite (industrial atmosphere) and ferrihydrite (marine atmosphere). - Abstract: A great deal of information is available on the atmospheric corrosion of mild steel in the short, mid and even long term, but studies of the structure and morphology of corrosion layers are less abundant and generally deal with those formed in just a few years. The present study assesses the structure and morphology of corrosion product layers formed on mild steel after 13 years of exposure in five Spanish atmospheres of different types: rural, urban, industrial and marine (mild and severe). The corrosion layers have been characterised by X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Long-term corrosion is seen to be more severe in the industrial and marine atmospheres, and less so in the rural and urban atmospheres. In all cases the corrosion rate is seen to decrease with exposure time, stabilising after the first 4-6 years of exposure. The most relevant aspects to be noted are (a) the great compaction of the rust layers formed in the rural and urban atmospheres, (b) the formation of hematite and ferrihydrite phases (not commonly found) in the industrial and marine atmospheres, respectively and (c) identification of the typical morphological structures of lepidocrocite (sandy crystals and flowery plates), goethite (cotton balls structures) and akaganeite (cotton balls structures and cigar-shaped crystals).

  13. Anti-corrosive Effects of Multi-Walled Carbon Nano Tube and Zinc Particle Shapes on Zinc Ethyl Silicate Coated Carbon Steel

    Jang, JiMan; Shon, MinYoung; Kwak, SamTak [Pukyong National University, Busan (Korea, Republic of)

    2016-01-15

    Zinc ethyl silicate coatings containing multi walled carbon nanotubes (MWCNTs) were prepared, to which we added spherical and flake shaped zinc particles. The anti-corrosive effects of MWCNTs and zinc shapes on the zinc ethyl silicate coated carbon steel was examined, using electrochemical impedance spectroscopy and corrosion potential measurement. The results of EIS and corrosion potential measurement showed that the zinc ethyl silicate coated with flake shaped zinc particles and MWCNT showed lesser protection to corrosion. These outcomes were in agreement with previous results of corrosion potential and corrosion occurrence.

  14. Corrosion Behavior of Austenitic and Duplex Stainless Steels in Lithium Bromide

    Ayo Samuel AFOLABI; Alaneme, K.K.; Samson Oluwaseyi BADA

    2009-01-01

    The corrosion behavior of austenitic and duplex stainless steels in various concentrations of lithium, bromide solution was investigated by using the conventional weight loss measurement method. The results obtained show that corrosion of these steels occurred due to the aggressive bromide ion in the medium. Duplex stainless steel shows a greater resistance to corrosion than austenitic stainless steel in the medium. This was attributed to equal volume proportion of ferrite and austenite in th...

  15. Inhibitive Performance of a Rust Converter on Corrosion of Mild Steel

    Zhao, X. D.; Cheng, Y. F.; Fan, W.; Vladimir, C.; Volha, V.; Alla, T.

    2014-11-01

    In this work, a rust converter consisting of two steps of processing solutions was prepared to convert iron rust of the steel surface into a protective conversion film. The performance of the converter was evaluated in both neutral and acidic solutions by various electrochemical measurements, including potentiodynamic polarization curves and electrochemical impedance spectroscopy, and surface characterization. The effect of temperature was investigated. It was found that the rust converter is able to effectively convert the iron rust into a conversion film, serving as a barrier layer to block corrosive species from reaching the steel surface.

  16. Effect of impurities on the corrosion behavior of CO2 transmission pipeline steel in supercritical CO2-water environments.

    Choi, Yoon-Seok; Nesic, Srdjan; Young, David

    2010-12-01

    The corrosion property of carbon steel was evaluated using an autoclave under CO(2)-saturated water phase and water-saturated CO(2) phase with impurities (O(2) and SO(2)) at 80 bar CO(2) and 50 °C to simulate the condition of CO(2) transmission pipeline in the carbon capture and storage (CCS) applications. The results showed that the corrosion rate of carbon steel in CO(2)-saturated water was very high and it increased with adding O(2) in the system due to the inhibition effect of O(2) on the formation of protective FeCO(3). It is noteworthy that corrosion took place in the water-saturated CO(2) phase under supercritical condition when no free water is present. The addition of O(2) increased the corrosion rates of carbon steel in water-saturated CO(2) phase. The addition of 0.8 bar SO(2) (1%) in the gas phase dramatically increased the corrosion rate of carbon steel from 0.38 to 5.6 mm/y. This then increased to more than 7 mm/y with addition of both O(2) and SO(2). SO(2) can promote the formation of iron sulfite hydrate (FeSO(3)·3H(2)O) on the steel surface which is less protective than iron carbonate (FeCO(3)), and it is further oxidized to become FeSO(4) and FeOOH when O(2) is present with SO(2) in the CO(2)-rich phase. The corrosion rates of 13Cr steel were very low compared with carbon steel in CO(2)-saturated water environments with O(2), whereas it was as high as carbon steel in a water-saturated CO(2) phase with O(2) and SO(2). PMID:21049923

  17. Chloride induced localized corrosion in simulated concrete pore solution: effect of a phosphate-based inhibitor on the behavior of 304L stainless steel compared to carbon steel

    In this paper, the acoustic emission technique coupled with electrochemical measurements was used to determine, in simulated concrete pore solution (Ca(OH)2), the critical value [Cl-] / [OH-], which prevents the pitting corrosion initiation of AISI 304L austenitic stainless steel, and to compare this critical value with that of the carbon steel in the same medium with and without inhibitor Na3PO4. The results show that for the austenitic stainless steel, the critical threshold of pitting corrosion initiation is around 5, while for carbon steel without inhibitor in Ca(OH)2 solution, it has a low value of about 0.6. However, the presence of the inhibitor Na3PO4 in this solution leads to the formation of a protective phosphate layer on the steel surface, increasing the critical ratio [Cl-] / [OH-] from 0.6 to 15. Under these conditions, the corrosion behavior of carbon steel is improved and, thanks to the blocking of pitting sites by the Na3PO4 inhibitor, it becomes much more resistant to localized corrosion than AISI 304L austenitic steel. (authors)

  18. Stress corrosion crack growth rates and general corrosion rates at crack tips of steels in high temperature water

    The maximum stress corrosion crack growth rates for a number of structural materials (steels and nickel alloys) have been measured in 288 C water. Also, the general corrosion rates of these materials have been determined from weight loss experiments in simulated stress corrosion crack tip electrolytes at 288 C. It is shown that the stress corrosion crack growth rates are typically twenty times faster than the general corrosion rates. This correlation holds over five orders of magnitude. It is concluded that strategies to prevent stress corrosion cracking in high temperature aqueous environments might include alloys of higher general corrosion resistance

  19. The corrosion of carbon steel in aqueous lithium hydroxide under a hydrogen blanket

    The corrosion behavior of carbon steel in 3 and 5 mol/L aqueous solutions of lithium hydroxide at 95 degrees C under a hydrogen atmosphere was investigated in immersion tests lasting ten days. Corrosion rates were determined by wight loss, and the corrosion products were characterized by bulk chemical analysis, by light and electron microscopy, and by powder X-ray diffraction. Corrosion was uniform and the corrosion rates were moderately high (0.42 mm/y in 3 mol/L and 0.56 mm/y in 5 mol/L). The corrosion products consisted of a mixture of well-formed, octahedral crystals, and poorly crystallized masses and spherules that formed by precipitation from solution. These products formed a scale on the metal surface that continually sloughed off and afforded only minor protection. Both phases were identified as lithium-iron oxides, each possessing a disordered, non-stoichiometric structure. The predominant phase was a magnetic spinel LiFe508 and the minor phase was LiFe02. A corrosion mechanism is outlined. (2 figs., 5 tabs., 20 refs.)

  20. Corrosion, Al containing corrosion barriers and mechanical properties of steels foreseen as structural materials in liquid lead alloy cooled nuclear systems

    A key problem in development of heavy liquid metal cooled nuclear energy and transmutation reactors is the corrosion of structural and fuel. Above 500 oC steels have to be protected by stable, thin oxide scales. A well understood measure is alloying of stable oxide formers into the surface. Two methods, alloying an Al layer into the steel surface using pulsed electron beams (GESA - gepulste Elektronenstrahlanlage) and coating the surface with an Al-alloy with subsequent GESA treatment are applied. In the range of 4-10 wt% Al on the surface a stable thin alumina scale is formed by Al diffusion to the surface and selective oxidation. The alumina scale grows only very slowly and prevents migration of oxygen into the steel as well as migration of steel components onto the surface. A number of corrosion experiments showed the good protective behaviour of Al scales in LBE with 10-6 wt% oxygen up to 650 oC and for exposure times up to 10,000 h. Furthermore the influence of parameters like stresses in the cladding wall, creep behaviour, different flow velocities of the LBE and changing temperatures and oxygen concentrations in LBE is discussed. This paper will provide an overview on the activities concerning Pb-PbBi corrosion and corrosion protection performed at the Institute of Pulsed Power and Microwave Technology (IHM) at the KIT.

  1. Moessbauer spectroscopy of corrosion products of mild steel due to microbiologically influenced corrosion

    Corrosion products of mild steel exposed to four different cultures of sulfur reducing bacteria (SRB) grown in a synthetic medium have been studied by transmission Moessbauer spectroscopy (TMS). Cultures of SRB studied are two hydrogenase positive strains, Desulfovibrio desulfuricans (DD) and Desulfovibrio vulgaris (DV) and two hydrogenase negative strains Desulfotomaculum orientis (DO) and Desulfotomaculum nigrificans (DN). The corrosion products generated on the coupons as well as in the broth were studied. In all the cases, the corrosion products removed from coupons showed the presence of green rust 2 (GR2), ferrous sulfides, γ-FeOOH and superparamagnetic (SPM) α-FeOOH in different proportions. The corrosion products from the broth showed a symmetrical central doublet, which indicates the presence of γ-FeOOH and SPM α-FeOOH along with ferrous sulfides. The corrosion products from coupons suspended in sewage water also showed the presence of GR 2 and ferrous sulfides together with oxyhydroxides. FTIR spectrum supports the presence of these phases in corrosion products. The formation of GR 2 on coupons seems to be the first step for the SRB induced corrosion. The corrosion rate has been found in the order of DO > DN > DV > DD. (author)

  2. Mechanical Properties and Corrosion Behavior of Low Carbon Steel Weldments

    Mohamed Mahdy

    2013-01-01

    Full Text Available This research involves studying the mechanical properties and corrosion behavior of “low carbon steel” (0.077wt% C before and after welding using Arc, MIG and TIG welding. The mechanical properties include testing of microhardness, tensile strength, the results indicate that microhardness of TIG, MIG welding is more than arc welding, while tensile strength in arc welding more than TIG and MIG.The corrosion behavior of low carbon weldments was performed by potentiostat at scan rate 3mV.sec-1 in 3.5% NaCl to show the polarization resistance and calculate the corrosion rate from data of linear polarization by “Tafel extrapolation method”. The results indicate that the TIG welding increase the corrosion current density and anodic Tafel slop, while decrease the polarization resistance compared with unwelded low carbon steel. Cyclic polarization were measured to show resistance of specimens to pitting corrosion and to calculate the forward and reveres potentials. The results show shifting the forward, reverse and pitting potentials toward active direction for weldments samples compared with unwelded sample.

  3. Hydrogen Diffusion and H{sub 2}S Corrosion in Steel

    Haugstveit, Bjarte Erlend

    2001-01-01

    The electrochemical permeation technique introduced by Devanathan and Stachurski has been used to measure the effective diffusivity of hydrogen in steel in a H{sub 2}S-saturated aqueous environment. The linear polarization resistance (LPR) method has been used to measure the corrosion rate. The effective diffusion coefficient of hydrogen has been found to be in the range of 1*10-12 to 7*10-11, depending on the environmental conditions. The corrosion film was identified as mackinawite, and it affected the permeation process of hydrogen. The results supported the assumption that the diffusion process can be described by a three layer model and indicated that the model could be reduced to a two layer model in the cases of iron and steel. A model aimed to describe the reaction pathway of hydrogen through the surface film and into the steel is proposed. The corrosion film influenced the corrosion rate, and it was least protective against corrosion at pH 6.5. Corrosion rates were in the range of 0.2-1 mm/year. The corrosion rate was increased significantly at pH 3.5, but the effect of the surface film was stronger and overshadowed the pH effect at the higher pH values. Increased flow velocity also lead to increased corrosion rate, but this effect was less significant compared to the effect of pH and the surface film. DEG decreased the corrosion rate. The uncertainty in the diffusion measurements was mainly due to the assumption of a constant sub-surface concentration of atomic hydrogen, which was not fulfilled. A method less dependent on constant surface conditions would probably yield better estimates of the effective diffusivity. The uncertainty in the corrosion measurements was mainly due to the uncertainty in the value of the Stern-Geary constant. The qualitative assumptions based on the results in this thesis are assumed to be valid. A test section designed for this thesis was tested and was found successful in corrosion rate measurements, but proved to be

  4. Development of Custom 465® Corrosion-Resisting Steel for Landing Gear Applications

    Daymond, Benjamin T.; Binot, Nicolas; Schmidt, Michael L.; Preston, Steve; Collins, Richard; Shepherd, Alan

    2016-04-01

    Existing high-strength low-alloy steels have been in place on landing gear for many years owing to their superior strength and cost performance. However, there have been major advances in improving the strength of high-performance corrosion-resisting steels. These materials have superior environmental robustness and remove the need for harmful protective coatings such as chromates and cadmium now on the list for removal under REACH legislation. A UK government-funded collaborative project is underway targeting a refined specification Custom 465® precipitation hardened stainless steel to replace the current material on Airbus A320 family aircraft main landing gear, a main fitting component developed by Messier-Bugatti-Dowty. This is a collaborative project between Airbus, Messier-Bugatti-Dowty, and Carpenter Technology Corporation. An extensive series of coupon tests on four production Heats of the material have been conducted, to obtain a full range of mechanical, fatigue, and corrosion properties. Custom 465® is an excellent replacement to the current material, with comparable tensile strength and fracture toughness, better ductility, and very good general corrosion and stress corrosion cracking resistance. Fatigue performance is the only significant area of deficit with respect to incumbent materials, fatigue initiation being often related to carbo-titanium-nitride particles and cleavage zones.

  5. Corrosion of CrN-coated steels for nuclear reactors in liquid Pb-Bi

    Corrosion tests of CrN-coated steels for nuclear reactors were conducted in liquid lead-bismuth (Pb-Bi) at 450degC and 550degC for 3000 h to investigate the applicability of CrN coating to a liquid Pb-Bi environment. CrN coatings on F82H (Fe-8Cr-2W-0.3V-0.04Ta-0.1C) and 316SS exhibited good compatibility in liquid Pb-Bi during corrosion test at 450degC. The CrN coating layer suffered heavy damage such as cracking and spalling, and showed no effectiveness as a protective layer in corrosion test at 550degC. Nickel and chromium in 316SS dissolved into Pb-Bi through the damaged coating layer at 550degC. The cracking and spalling were not found after heating CrN-coated steels in Ar gas at 550degC. It is considered that stresses caused by the difference of thermal expansion coefficients between CrN and steels led to cracking and spalling of the CrN coating through corrosion attack by liquid Pb-Bi at 550degC. (author)

  6. Corrosion Behavior of Ultra-high Strength Steel 300M in Different Simulated Marine Environments

    GUO Qiang; LIU Jianhua; YU Mei; LI Songmei

    2016-01-01

    Corrosion behavior of 300M in neutral corrosion environments containing NaCl simulated by total immersion (TI), salt spraying (SS) and periodic immersion (PI), was investigated by surface analysis techniques, corrosion weight-loss method, and electrochemical measurements. In total immersion environment, rust on the steel consisted of a porous outer rust layer with main constituent ofγ-FeOOH, and an inner rust layer of dense Fe3O4 iflm with network broad cracks. In salt spraying environment, outer rust with main composition ofγ-FeOOH/α-FeOOH/Fe3O4 was compact, and inner rust showed dense Fe3O4 iflm. Rust formed by periodic immersion exhibited a compact outer rust layer with constituent ofα-FeOOH/γ-FeOOH/Fe3O4 and an inner rust layer with composition ofα-FeOOH/α-Fe2O3; inner rust showed a ultra-dense iflm adherent to the steel. The corrosion rate showed a rule ofvs(salt spraying)>vti(total immersion)>>vpi(periodic immersion) in 0-240 h, andvss≈vti»vpiin 240-720 h. The rust formed by periodic immersion was dense and compact, with stable electrochemical properties, and had excellent protection on the steel. Humidity and oxygen concentration in all the environments played major roles in rust formation.

  7. Development of highly corrosion resistant 18-8 stainless steel for nuclear fuel reprocessing plants

    Corrosion behavior of ultra low carbon 18-8 stainless steel was evaluated in boiling nitric acid environment. Although ultra low carbon stainless steel shows excellent corrosion resistance, it is, due to low carbon content, easily induced martensite by cold work. Increasing the strain induced martensite by cold work, the corrosion rate of 18-8 stainless steel increased. Corrosion rate is summarized as a function of stability factor with represents a resistance to martensite transformation induced by cold work and highly austenitic stabilized steel showed better corrosion resistance. Ultra low carbon 18-8 stainless steel which is highly stabilized austenite was designed and manufactured with commercial mill. The development steel showed an excellent corrosion resistance in boiling nitric acid even after cold work. The corrosion rate of the welded joint was also excellent as well as matrix

  8. Accelerated corrosion of stainless steel in thiocyanate-containing solutions

    Pistorius, P Chris; Li, Wen

    2012-09-19

    It is known that reduced sulfur compounds (such as thiocyanate and thiosulfate) can accelerate active corrosion of austenitic stainless steel in acid solutions, but before we started this project the mechanism of acceleration was largely unclear. This work combined electrochemical measurements and analysis using scanning electron microscopy (SEM) and X-ray photo-electron spectroscopy (XPS), which provided a comprehensive understanding of the catalytic effect of reduced sulfur species on the active corrosion of stainless steel. Both the behavior of the pure elements and the steel were studied and the work focused on the interaction between the pure elements of the steel, which is the least understood area. Upon completion of this work, several aspects are now much clearer. The main results from this work can be summarized as follows: The presence of low concentrations (around 0.1 mM) of thiocyanate or tetrathionate in dilute sulfuric acid greatly accelerates the anodic dissolution of chromium and nickel, but has an even stronger effect on stainless steels (iron-chromium-nickel alloys). Electrochemical measurements and surface analyses are in agreement with the suggestion that accelerated dissolution really results from suppressed passivation. Even well below the passivation potential, the electrochemical signature of passivation is evident in the electrode impedance; the electrode impedance shows clearly that this pre-passivation is suppressed in the presence of thiocyanate. For the stainless steels, remarkable changes in the morphology of the corroded metal surface and in the surface concentration of chromium support the suggestion that pre-passivation of stainless steels is suppressed because dissolution of chromium is accelerated. Surface analysis confirmed that adsorbed sulfur / sulfide forms on the metal surfaces upon exposure to solutions containing thiocyanate or thiosulfate. For pure nickel, and steels containing nickel (and residual copper), bulk sulfide

  9. Corrosion behavior of Al-Fe-sputtering-coated steel, high chromium steels, refractory metals and ceramics in high temperature Pb-Bi

    Corrosion tests of Al-Fe-coated steel, high chromium steels, refractory metals and ceramics were carried out in high temperature Pb-Bi at 700 C degrees. Oxygen concentrations in this experiment were 6.8*10-7 wt.% for Al-Fe-coated steels and 5*10-6 wt.% for high chromium steels, refractory metals and ceramics. All specimens were immersed in molten Pb-Bi in a corrosion test pot for 1.000 hours. Coating was done with using the unbalanced magnetron sputtering (UBMS) technique to protect the steel from corrosion. Sputtering targets were Al and SUS-304. Al-Fe alloy was coated on STBA26 samples. The Al-Fe alloy-coated layer could be a good protection layer on the surface of steel. The whole of the Al-Fe-coated layer still remained on the base surface of specimen. No penetration of Pb-Bi into this layer and the matrix of the specimen. For high chromium steels i.e. SUS430 and Recloy10, the oxide layer formed in the early time could not prevent the penetration of Pb-Bi into the base of the steels. Refractory metals of tungsten (W) and molybdenum (Mo) had high corrosion resistance with no penetration of Pb-Bi into their matrix. Penetration of Pb-Bi into the matrix of niobium (Nb) was observed. Ceramic materials were SiC and Ti3SiC2. The ceramic materials of SiC and Ti3SiC2 had high corrosion resistance with no penetration of Pb-Bi into their matrix. (authors)

  10. Influence of Heat Treatments on the Corrosion Resistance of Medium -Carbon Steel using Sulfuric Spring Water

    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

  11. Evaluation of Encapsulated Inhibitor for Autonomous Corrosion Protection

    Johnsey, M. N.; Li, W.; Buhrow, J. W.; Calle, L. M.; Pearman, B. P.; Zhang, X.

    2015-01-01

    This work concerns the development of smart coating technologies based on microencapsulation for the autonomous control of corrosion. Microencapsulation allows the incorporation of corrosion inhibitors into coating which provides protection through corrosion-controlled release of these inhibitors.One critical aspect of a corrosion protective smart coating is the selection of corrosion inhibitor for encapsulation and comparison of the inhibitor function before and after encapsulation. For this purpose, a systematic approach is being used to evaluate free and encapsulated corrosion inhibitors by salt immersion. Visual, optical microscope, and Scanning Electron Microscope (with low-angle backscatter electron detector) are used to evaluate these inhibitors. It has been found that the combination of different characterization tools provide an effective method for evaluation of early stage localized corrosion and the effectiveness of corrosion inhibitors.

  12. Synergistic Effect on Corrosion Inhibition Efficiency of Ginger Affinale Extract in Controlling Corrosion of Mild Steel in Acid Medium

    The corrosion inhibition nature of Ginger affinale extract for the corrosion of mild steel in 0.5N H2SO4 was investigated using weight loss, electrochemical impedance and potentiodynamic polarization methods. The results revealed that Ginger affinale extract acts as a good corrosion inhibitor in 0.5N H2SO4 medium. The inhibition efficiency increased with an increase in inhibitor concentration. The inhibition could be attributed to the adsorption of the inhibitor on the steel surface

  13. Advanced zinc phosphate conversion and pre-ceramic polymetallosiloxane coatings for corrosion protection of steel and aluminum, and characteristics of polyphenyletheretherketone-based materials. Final report

    Sugama, T.; Carciello, N.R.

    1992-07-01

    Anhydrous zinc phosphate (Zn{center_dot}Ph) coatings deposited by immersing the steel in transition Co, Ni, and Mn cation-incorporated phosphating solutions were investigated. Two features for the anhydrous 340C-heated (Zn{center_dot}Ph) were addressed; one was to determine if electron trapping of adsorbed CO{sup 2+} and Ni{sup 2+} ions acts to inhibit the cathodic reaction on the (Zn{center_dot}Ph), and the second was to determine the less susceptibility of the {alpha}-Zn{sub 3}(PO{sub 4}){sub 2} phase to alkali-induced dissolution. The factors governing film-forming of pre-ceramic polymetallosiloxane (PMS) coatings for Al substrates were investigated. Four factors were important in obtaining a good film: (1) formation of organopolymetallosiloxane at sintering temperatures of 150C; (2) pyrolytic conversion at 350C into an amorphous PMS network structure in which the Si-O-M linkage were moderately enhanced; (3) noncrystalline phases; and (4) formation of interfacial oxane bond between PMS and Al oxide. Formation of well-crystallized polyphenyletheretherketone (PEEK) in vicinity of silica aggregates was found in the molted body made in N{sub 2}. Crystalline PEEK contributed to thermal and hydrothermal stabilities of mortar specimens at temperatures up to 200C, and resistance in 5 wt % H{sub 2}SO{sub 4} solution at 80C.

  14. Accelerated Test Method for Corrosion Protective Coatings Project

    Falker, John; Zeitlin, Nancy; Calle, Luz

    2015-01-01

    This project seeks to develop a new accelerated corrosion test method that predicts the long-term corrosion protection performance of spaceport structure coatings as accurately and reliably as current long-term atmospheric exposure tests. This new accelerated test method will shorten the time needed to evaluate the corrosion protection performance of coatings for NASA's critical ground support structures. Lifetime prediction for spaceport structure coatings has a 5-year qualification cycle using atmospheric exposure. Current accelerated corrosion tests often provide false positives and negatives for coating performance, do not correlate to atmospheric corrosion exposure results, and do not correlate with atmospheric exposure timescales for lifetime prediction.

  15. Effect of antimony on the corrosion behavior of low-alloy steel for flue gas desulfurization system

    The alloying effect of Sb in a new low-alloy steel for the purpose of FGD materials was investigated by potentiodynamic polarization, linear polarization resistance measurement, electrochemical impedance spectroscopy (EIS) and weight loss measurements in an aggressive solution of 16.9 vol.% H2SO4 + 0.35 vol.% HCl (modified green death solution) at 60 deg. C, pH -0.3. All measurements confirmed the marked improvement in the corrosion behavior of the low-alloy steel via the addition of a small amount of Sb, particularly for the 0.10Sb steel. Pitting corrosion was detected by scanning electron microscopy (SEM) on the surface of blank steel and 0.05Sb steel, but not 0.10Sb steel, after weight loss measurements. X-ray photoelectron spectroscopy (XPS) analysis of the corroded surfaces after EIS and linear polarization measurements showed that the decrease in corrosion rates was due to the formation of a protective Sb2O5 oxide film on the surface of the Sb-containing steels. Moreover, the addition of 0.10% Sb stimulated the development of high corrosion inhibiting, Cu-containing compounds which further inhibited the anodic and cathodic reactions

  16. A Study of Electrochemical Protection of Carbon Steels in Sulfuric Acid Solutions - Electrochemical Protection Diagrams of Metals (1) -

    Electrochemical protection of carbon steels was studied in sulfuric acid solutions. The main results obtained are as follows: 1) Electrochemical protection diagrams of carbon steels in sulfuric acid solutions can be drawn with the data from Jeon's determination method of the optimum cathodic protection potential, the Tafel extrapolation and the characteristics of anodic polarization curves, and the diagram also represent various practical protection data. 2) Corrosion rates of carbon steels in the more concentration than 45% solutions are very low because they are on sulfaction or passivation in the solution, but the rates in the less concentration than the solutions are very high since they are on activation. 3) SS 41 steel is suitable in the more concentration than 45% solutions but SM 50 steel is relatively good in the less concentration than the solutions from the economical view

  17. A Corrosion Sensor for Monitoring the Early-Stage Environmental Corrosion of A36 Carbon Steel

    Dong Chen

    2014-08-01

    Full Text Available An innovative prototype sensor containing A36 carbon steel as a capacitor was explored to monitor early-stage corrosion. The sensor detected the changes of the surface- rather than the bulk- property and morphology of A36 during corrosion. Thus it was more sensitive than the conventional electrical resistance corrosion sensors. After being soaked in an aerated 0.2 M NaCl solution, the sensor’s normalized electrical resistance (R/R0 decreased continuously from 1.0 to 0.74 with the extent of corrosion. Meanwhile, the sensor’s normalized capacitance (C/C0 increased continuously from 1.0 to 1.46. X-ray diffraction result indicates that the iron rust on A36 had crystals of lepidocrocite and magnetite.

  18. Microbially influenced corrosion of stainless steel by marine bacterium Vibrio natriegens: (I) Corrosion behavior

    Cheng Sha; Tian Jintao [Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100 (China); Chen Shougang, E-mail: sgchen@ouc.edu.cn [Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100 (China); Lei Yanhua; Chang Xueting; Liu Tao [Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100 (China); Yin Yansheng, E-mail: yys2006@ouc.edu.cn [Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100 (China)

    2009-04-30

    The microbially influenced corrosion of stainless steel (SS) by marine bacterium Vibrio natriegens (V. natriegens) was investigated using surface analysis (atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDXA)) and electrochemical techniques (the open circuit potential, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization curves ). AFM images corroborated the results from the EIS models which show biofilm attachment and subsequent detachment over time. The SEM images revealed the occurrence of micro-pitting corrosion underneath the biofilms on the metal surface after the biofilm removal. The presence of carbon, oxygen, phosphor and sulfur obtained from EDXA proved the formation of biofilm. The electrochemical results showed that the corrosion of SS was accelerated in the presence of V. natriegens based on the decrease in the resistance of the charge transfer resistance (R{sub ct}) obtained from EIS and the increase in corrosion current densities obtained from potentiodynamic polarization curves.

  19. The effects of radiolysis on the corrosion and stress corrosion behavior of 316 stainless steels

    Duquette, D.J.; Steiner, D.

    1993-09-01

    This program is focused on the corrosion, stress corrosion and corrosion fatigue behavior of Type 316 stainless steel (316SS) at 50, 90, and 130 C in high-purity water. Irradiated solution tests are performed using high-energy photon radiation. Purpose of this work is to determine the effects of radiolysis products on the environmental stability of 316SS in support of the ITER first wall/shield/blanket design. Preliminary results suggest that irradiation of pure water at 50 C results in a shift in the electrochemical potential for 316SS of approximately 100mV in the active direction and nearly an order of magnitude increase in the passive current density as compared to non-irradiated conditions. This proposal outlines a three-year program to develop corrosion design criteria for the use of 316SS in an ITER environment.

  20. Microbially influenced corrosion of stainless steel by marine bacterium Vibrio natriegens: (I) Corrosion behavior

    The microbially influenced corrosion of stainless steel (SS) by marine bacterium Vibrio natriegens (V. natriegens) was investigated using surface analysis (atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDXA)) and electrochemical techniques (the open circuit potential, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization curves ). AFM images corroborated the results from the EIS models which show biofilm attachment and subsequent detachment over time. The SEM images revealed the occurrence of micro-pitting corrosion underneath the biofilms on the metal surface after the biofilm removal. The presence of carbon, oxygen, phosphor and sulfur obtained from EDXA proved the formation of biofilm. The electrochemical results showed that the corrosion of SS was accelerated in the presence of V. natriegens based on the decrease in the resistance of the charge transfer resistance (Rct) obtained from EIS and the increase in corrosion current densities obtained from potentiodynamic polarization curves.

  1. Corrosion resistance of stainless steel pipes in soil

    Sjoegren, L.; Camitz, G. [Swerea KIMAB AB, Box 55970, SE-102 16 Stockholm (Sweden); Peultier, J.; Jacques, S.; Baudu, V.; Barrau, F.; Chareyre, B. [Industeel and ArcelorMittal R and D, 56 rue Clemenceau, BP19, FR-71201 le Creusot, Cedex (France); Bergquist, A. [Outokumpu Stainless AB, P.O. Box 74, SE-774 22 Avesta (Sweden); Pourbaix, A.; Carpentiers, P. [Belgian Centre for Corrosion Study, Avenue des Petits-Champs 4A, BE 1410 Waterloo (Belgium)

    2011-04-15

    To be able to give safe recommendations concerning the choice of suitable stainless steel grades for pipelines to be buried in various soil environments, a large research programme, including field exposures of test specimens buried in soil in Sweden and in France, has been performed. Resistance against external corrosion of austenitic, super austenitic, lean duplex, duplex and super duplex steel grades in soil has been investigated by laboratory tests and field exposures. The grades included have been screened according to their critical pitting-corrosion temperature and according to their time-to-re-passivation after the passive layer has been destroyed locally by scratching. The field exposures programme, being the core of the investigation, uses large specimens: 2 m pipes and plates, of different grades. The exposure has been performed to reveal effects of aeration cells, deposits or confined areas, welds and burial depth. Additionally, investigations of the tendency of stainless steel to corrode under the influence of alternating current (AC) have been performed, both in the laboratory and in the field. Recommendations for use of stainless steels under different soil conditions are given based on experimental results and on operating experiences of existing stainless steel pipelines in soil. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Role of surface finishing on pitting corrosion of a duplex stainless steel in seawater

    Salah-Rousset, N. Ben; Chaouachi, M. A.; Chellouf, A.

    1996-04-01

    Localized corrosion of duplex UNS S32550 stainless steel in seawater was investigated in the laboratory and in field trials for several surface finish conditions: polished, ground, and sandblasted. Electrochemical data obtained by polarization curves showed that the smoother, polished surface had better characteristics (higher pitting and protection potentials) than the ground or sandblasted surfaces. However, despite its high degree of roughness, the sandblasted surface was the most resistant in field conditions, exhibiting the lowest number of sites attacked. Internal compressive stresses created by sandblasting seem also to have an “unsensitizing” effect on sensitized zones that exist in cast steel (due to repairs of mold defects), reducing its susceptibility to microbiologically influenced corrosion (MIC). Such stresses are not generated in polished or ground surfaces, and localized MIC attack can occur.

  3. 3DII implantation effect on corrosion properties of the AISI/SAE 1020 steel

    Dulce M., H.J.; Rueda V., Alejandro [Universidad Francisco de Paula Santander, A.A. 1055, Cucuta (Colombia); Dougar-Jabon, Valeri [Universidad Industrial de Santander, A.A. 678, Bucaramanga (Colombia)

    2005-08-01

    The three dimensional ion implantation technology (3DII) is one of the methods of improving the tribological characteristics and resistance to hydrogen embrittlement processes in metals. In this report, some results concerning the resistance effect of nitrogen ion implantation to oxidation of the sample, made of AISI/SAE 1020 steel, are given. The nitrogen ions were implanted in the discharge chamber of the JUPITER reactor. Both the treated and untreated samples were tested through potential-static measurements, which permitted to determine the corrosion current, the slopes that characterise the braking level of anode and cathode reactions. The polarization resistance near the corrosion potential is calculated. The results of the study encourage to consider the nitrogen ion implantation in high voltage and low pressure discharges as one of the methods of anticorrosive protection which do not change the geometric configuration of the treated steel pieces. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Mechanical properties and corrosion resistance of dissimilar stainless steel welds

    J. Łabanowski

    2007-01-01

    Purpose: The purpose of this paper is to determine the influence of welding on microstructure, mechanical properties, and stress corrosion cracking resistance of dissimilar stainless steels butt welded joints.Design/methodology/approach: Duplex 2205 and austenitic 316L steels were used. Butt joints of plates 15 mm in thickness were performed with the use of submerged arc welding (SAW) method. The heat input was in the range of 1.15 – 3.2 kJ/mm. Various plates’ edge preparation...

  5. Inhibition of mild steel corrosion using Jatropha Curcas leaf extract

    OLORUNFEMI MICHAEL AJAYI; JAMIU KOLAWOLE ODUSOTE; RAHEEM ABOLORE YAHYA

    2014-01-01

    Jatropha Curcas leaf was investigated as a green inhibitor on the degradation of mild steel in 4 M HCl and 4 M H2SO4 aqueous solutions using gasometric technique. Mild steel coupons of dimension 2 × 1.5 cm were immersed in test solutions of uninhibited acid and also those with extract concentrations of 4 ml, 6 ml, 8 ml and 10 ml at 30 oC, for up to 30 minutes. The results showed that as the concentration of the extract increases, there was reduction in the corrosion rate. As the extract conce...

  6. Corrosion monitoring of different steels by thin layer activation

    For corrosion monitoring, the behavior of various steels (Sanicro 28, AISI 316 L, SAF 2507) and a carbon steel were investigated by thin layer activation (TLA) in acid solutions containing chloride. A loop system with a sample holder as well as a temperature and a flow control device were used in laboratory tests. Experimental parameters like fluid temperature, H2SO4 concentration and running time were selected as a function of the specific material under investigation. The congruence of Ta results was verified by comparison with mass loss data, obtained by gravimetry

  7. The New-generation of Green Surfactant(Alkylpolyglucoside)as an Inhibitor to the Corrosion of 907 Steel in Seawater

    Min DU; Rong Jie GAO; Ping GONG; Qing Zhang WANG

    2004-01-01

    Weight-loss trials and potentiodynamic polarization curves have been used to study the inhibitive properties of alkylpolyglucoside (APG) towards the 907 steel in seawater.The inhibition was different, if the length of alkyl chain APG was different.As the result, calcium gluconate, zinc sulfate and APG can protect 907 steel from being corrupted in static seawater.The compound corrosion inhibitor was found to control both the anodic process and the cathodic process.

  8. The kinetics of pitting corrosion of carbon steel

    This report describes progress between April 1986 and May 1987 in a programme studying the kinetics of pitting corrosion in carbon steel containers for the disposal of high level nuclear waste in a granitic repository. Experimental studies are being undertaken with the following objectives: (a) To improve the validation of a mathematical model for the propagation of pitting corrosion. (b) To develop an improved statistical method for analysing experimental pit growth data to take account of the difference in area of laboratory specimens and full size waste containers. (c) To estimate the maximum period during which pitting attack is feasible under repository conditions by calculating the time during which the diffusion of oxygen to the containers will be sufficient to maintain carbon steel in its passive state. Work in the first 14 months of the project has concentrated on (b) and to a lesser extent on (c). (orig./MM)

  9. Corrosion Protection of Launch Infrastructure and Hardware Through the Space Shuttle Program

    Calle, L. M.

    2011-01-01

    Corrosion, the environmentally induced degradation of materials, has been a challenging and costly problem that has affected NASA's launch operations since the inception of the Space Program. Corrosion studies began at NASA's Kennedy Space Center (KSC) in 1966 during the Gemini/Apollo Programs with the evaluation of long-term protective coatings for the atmospheric protection of carbon steel. NASA's KSC Beachside Corrosion Test Site, which has been documented by the American Society of Materials (ASM) as one of the most corrosive, naturally occurring environments in the world, was established at that time. With the introduction of the Space Shuttle in 1981, the already highly corrosive natural conditions at the launch pad were rendered even more severe by the acidic exhaust from the solid rocket boosters. In the years that followed, numerous efforts at KSC identified materials, coatings, and maintenance procedures for launch hardware and equipment exposed to the highly corrosiye environment at the launch pads. Knowledge on materials degradation, obtained by facing the highly corrosive conditions of the Space Shuttle launch environment, as well as limitations imposed by the environmental impact of corrosion control, have led researchers at NASA's Corrosion Technology Laboratory to establish a new technology development capability in the area of corrosion prevention, detection, and mitigation at KSC that is included as one of the "highest priority" technologies identified by NASA's integrated technology roadmap. A historical perspective highlighting the challenges encountered in protecting launch infrastructure and hardware from corrosion during the life of the Space Shuttle program and the new technological advances that have resulted from facing the unique and highly corrosive conditions of the Space Shuttle launch environment will be presented.

  10. Effect of microstructure and Cr content in steel on CO{sub 2} corrosion

    Ueda, Masakatsu [Sumitomo Metal Industries, Ltd., Amagasaki (Japan). Iron and Steel Research Labs.; Ikeda, Akio [Sumitomo Metal Industries, Ltd., Osaka (Japan)

    1996-08-01

    The effect of microstructure and Cr content in steels on CO{sub 2} corrosion was investigated by using steels containing Cr content from 0 to 13 mass% melted in laboratory and Steels J55, N80 and L80(API Grade) melted in the mill. Temperatures and H{sub 2}S contamination were considered as environmental factors. In CO{sub 2} environments, the temperature giving a maximum corrosion rate, T{sub max.}, existed in carbon and Cr steels. T{sub max.} increased together with Cr content, and T{sub max.} of 0, 1, 2 and 13% Cr steels was about 80, 100, 120 and 225 C, respectively. Because of this behavior, the relationship between Cr content and corrosion rate was linear at 60 C, but the corrosion rate was highest on the steel with around 1 mass% Cr at 100 C. H{sub 2}S contamination for CO{sub 2} corrosion suppressed the corrosion rate and localized-corrosion in the temperature region whose corrosion rate showed a maximum value. It was clarified that this was related to the formation of Fe-sulfides from EPMA analysis and the solubility of the corrosion products. Concerning microstructure, Steel J55 with ferritic-pearlitic microstructure showed good corrosion resistance for localized-corrosion compared with Steel N80 and L80 with martensitic microstructure.

  11. Corrosion of an austenite and ferrite stainless steel weld

    BRANIMIR N. GRGUR; VLADANA N. RAJAKOVIĆ-OGNJANOVIĆ

    2011-01-01

    Dissimilar metal connections are prone to frequent failures. These failures are attributed to the difference in the mechanical properties across the weld, the coefficients of thermal expansion of the two types of steels and the resulting creep at the interface. For the weld analyzed in this research, it was shown that corrosion measurements can be used for a proper evaluation of the quality of weld material and for the prediction of whether or not the material, after the applied welding proce...

  12. Role of direct microbial electron transfer in corrosion of steels

    Mehanna, Maha; Basséguy, Régine; Délia, Marie-Line; Bergel, Alain

    2009-01-01

    It has recently been discovered that many microbial species have the capacity to connect their metabolism to solid electrodes, directly exchanging electrons with them through membrane-bound redox compounds,nevertheless such a direct electron transfer pathway has been evoked rarely in the domain of microbial corrosion. Here was evidenced for the first time that the bacterium Geobacter sulfurreducens is able to increase the free potential of 304 L stainless steel up to 443 mV in only a few hour...

  13. Microgalvanic corrosion of laser-welded HSLA steels

    Looi, Y.-M.

    2008-01-01

    Laser welding of galvanized high strength low alloy (HSLA) steels leads to the evaporation of zinc at the weld and the formation of a heat-affected-zone (HAZ). High heat input due to welding generates macro galvanic coupling between the weld and the parent metal as well as micro galvanic corrosion at different microstructures of the weld, HAZ and the parent metal. Different microstructural substructures exhibit different electrochemical characteristics, potentially leading to microgalvanic co...

  14. Influence of remanent magnetization on pitting corrosion in pipeline steel

    Espina-Hernandez, J. H. [ESIME Zacatenco, SEPI Electronica Instituto Politecnico Nacional Mexico, D. F. (Mexico); Caleyo, F.; Hallen, J. M. [DIM-ESIQIE, Instituto Politecnico Nacional Mexico D. F. (Mexico); Lopez-Montenegro, A.; Perez-Baruch, E. [Pemex Exploracion y Produccion, Region Sur Villahermosa, Tabasco (Mexico)

    2010-07-01

    Statistical studies performed in Mexico indicate that leakage due to external pitting corrosion is the most likely cause of failure of buried pipelines. When pipelines are inspected with the magnetic flux leakage (MFL) technology, which is routinely used, the magnetization level of every part of the pipeline changes as the MFL tool travels through it. Remanent magnetization stays in the pipeline wall after inspection, at levels that may differ from a point to the next. This paper studies the influence of the magnetic field on pitting corrosion. Experiments were carried out on grade 52 steel under a level of remanent magnetization and other laboratory conditions that imitated the conditions of a pipeline after an MLF inspection. Non-magnetized control samples and magnetized samples were subjected to pitting by immersion in a solution containing chlorine and sulfide ions for seven days, and then inspected with optical microscopy. Results show that the magnetic field in the pipeline wall significantly increases pitting corrosion.

  15. Atmospheric corrosion evaluation of galvanised steel by thin layer activation

    The release of certain metals, such as zinc, from outdoor constructions due to atmospheric corrosion is of some concern. For risk assessments the evaluation of the amount of released metal is of importance. Various methods can be used to study the release of metals. These include those using radiotracers, such as thin layer activation (TLA). To verify the reliability of TLA with respect to conventional techniques in the evaluation of atmospheric corrosion, galvanised steel was exposed to a mild marine environment. The amount of zinc in the corrosion products, released through artificial leaching, at different time intervals was evaluated by TLA and atomic absorption spectroscopy (AAS). A good correlation between the results was found indicating the feasibility of TLA for these release studies

  16. High temperature corrosion of low and high alloy steels under molten carbonate fuel cell conditions

    Biedenkopf, P.; Spiegel, M.; Grabke, H.J. [Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany)

    1997-08-01

    The corrosion behavior of eight low and high alloy steels was investigated under simulating the conditions at the cathode of a molten carbonate fuel cell at 650 C. Different Li-containing iron oxides (LiFeO{sub 2} and LiFe{sub 5}O{sub 8}) were formed in contact with the eutectic (Li, K)-carbonate melt depending on the Cr-content of the steel. These oxides show low solubility in the melt and protect the metallic material against further corrosive attack. Fast growing scales of Fe{sub 3}O{sub 4} and LiFe{sub 5}O{sub 8} were observed on the low alloy ferritic steel 10 CrMo 9 10. Higher alloy steels form LiFeO{sub 2} in contact with the melt and mixed Fe-Cr-spinels underneath. Steels with Cr-contents over 20 wt.% Cr form a mixed LiCr{sub 1-x}Fe{sub x}O{sub 2} and LiCrO{sub 2} layer in contact with the metal. Marker experiments on the commercial steel 1.4404 (X2 CrNiMo 17 13 2) show that the outer LiFeO{sub 2} layer grows mainly by outward diffusion of iron ions (Fe{sup 3+}), whereas the inner (Fe,Ni)Cr{sub 2}O{sub 4} spinel layer grows inward. After 500 hours, LiFe{sub 5}O{sub 8} was formed between the spinel and the LiFeO{sub 2} layer, but it had disappeared after several thousand hours of exposure as it was fully transformed to LiFeO{sub 2}. Co-containing LiFeO{sub 2} was found after 500 hours on the high Co-containing steel 1.4971 (X12 CrCoNi 21 20), but is not stable after several thousand hours exposure. Co diffuses outward to form a protective LiCoO{sub 2} layer of a few microns in thickness. Protective Cr{sub 2}O{sub 3} layers were not observed on steels with high Co-content ({>=}25 wt.% Cr) due to peroxide ions in the melt, which cause oxidation Cr{sub 2}O{sub 3} and flux to chromate, which is highly soluble in the melt. Further quantitative investigations on total corrosion considering the chromate formation have shown that high alloy steels with high amounts of Cr form mainly K{sub 2}CrO{sub 4}. (orig.) 22 refs.

  17. High temperature corrosion of low and high alloy steels under molten carbonate fuel cell conditions

    The corrosion behavior of eight low and high alloy steels was investigated under simulating the conditions at the cathode of a molten carbonate fuel cell at 650 C. Different Li-containing iron oxides (LiFeO2 and LiFe5O8) were formed in contact with the eutectic (Li, K)-carbonate melt depending on the Cr-content of the steel. These oxides show low solubility in the melt and protect the metallic material against further corrosive attack. Fast growing scales of Fe3O4 and LiFe5O8 were observed on the low alloy ferritic steel 10 CrMo 9 10. Higher alloy steels form LiFeO2 in contact with the melt and mixed Fe-Cr-spinels underneath. Steels with Cr-contents over 20 wt.% Cr form a mixed LiCr1-xFexO2 and LiCrO2 layer in contact with the metal. Marker experiments on the commercial steel 1.4404 (X2 CrNiMo 17 13 2) show that the outer LiFeO2 layer grows mainly by outward diffusion of iron ions (Fe3+), whereas the inner (Fe,Ni)Cr2O4 spinel layer grows inward. After 500 hours, LiFe5O8 was formed between the spinel and the LiFeO2 layer, but it had disappeared after several thousand hours of exposure as it was fully transformed to LiFeO2. Co-containing LiFeO2 was found after 500 hours on the high Co-containing steel 1.4971 (X12 CrCoNi 21 20), but is not stable after several thousand hours exposure. Co diffuses outward to form a protective LiCoO2 layer of a few microns in thickness. Protective Cr2O3 layers were not observed on steels with high Co-content (≥25 wt.% Cr) due to peroxide ions in the melt, which cause oxidation Cr2O3 and flux to chromate, which is highly soluble in the melt. Further quantitative investigations on total corrosion considering the chromate formation have shown that high alloy steels with high amounts of Cr form mainly K2CrO4. (orig.)

  18. Microbial corrosion and cracking in steel. Results from a screening of soil corrosivity using weight loss coupons

    Vendelbo Nielsen, L.

    1998-08-01

    A series of field measurements (49 in all) of the corrosion rate on steel exposed in different types of soil has been conducted by means of weight loss coupons. Additional measurements included pH, open circuit corrosion potential (OCP), soil resistivity, and analysis of the chemical composition of the corrosion products formed during the exposure. A brief discussion of the corrosion rate dependency on these additional parameters has been presented. (au)

  19. Cyclotriphosphazene and TiO2 reinforced nanocomposite coated on mild steel plates for antibacterial and corrosion resistance applications

    Krishnadevi, Krishnamoorthy; Selvaraj, Vaithilingam

    2016-03-01

    The mild steel surface has been modified to impart anticorrosion and antibacterial properties through a dip coating method followed by thermal curing of a mixture containing amine terminated cyclotriphosphazene and functionalized titanium dioxide nanoparticles reinforced benzoxazine based cyanate ester composite (ATCP/FTiO2/Bz-CE). The corrosion resistance behavior of coating material has been investigated by electrochemical and antibacterial studies by disc diffusion method. The nanocomposites coated mild steels have displayed a good chemical stability over long immersion in a corrosive environment. The protection efficiency has found to be high for ATCP/FTiO2/Bz-CE composites, which can be used in microelectronics and marine applications.

  20. Corrosion of carbon steel in sodium methanoate solutions

    The behaviour of steel electrodes in sodium methanoate solutions was studied by coupling electrochemical techniques (voltammetry, OCP vs. time) with in situ micro-Raman spectroscopy analyses of the corrosion products. The polarisation curves depended strongly on the methanoate concentration. For the smallest concentration (10-3 mol L-1), the current density increased regularly with the applied potential. So the behaviour of the electrode was typical of an active material. In contrast, for the largest concentration (10-1 mol L-1), the curves obtained were typical of a passive material. Methanoate ions favoured growth and stability of a passive oxide film more likely by adsorbing on its surface. The polarisation curve obtained for the intermediate concentration (10-2 mol L-1) was unusual and testified of an imperfect passivation of the steel surface. Finally, steel electrodes were left at the open circuit potential in the methanoate solutions. In any case, the passivity was rapidly lost and a general corrosion of the surface took place. In situ Raman spectroscopy analyses at the early stage of the corrosion process demonstrated that the first product to form was a green rust, GR(HCOO-). It was oxidised later into γ-FeOOH (lepidocrocite) by dissolved O2. The process is then typical of what is usually observed in neutral or alkaline media, whatever the anions present and responsible of the GR formation. A new and detailed characterisation of GR(HCOO-) by X-ray diffraction was performed and a crystal structure is proposed.

  1. Stress Corrosion Cracking Behavior of Cast Stainless Steels

    Casting of austenitic stainless steels offers the possibility of directly producing large and/or relatively complex structures, such as the first wall shield modules or the diverter cassette for the ITER fusion reactor. Casting offers major cost savings when compared to fabrication via welding of quarter modules machined from large forgings. However, the strength properties of such cast components are typically considered inferior to those of conventionally forged and annealed components. To improve and validate cast stainless steel as a substitute for wrought stainless steel, a development and testing program was initiated, utilizing nitrogen and manganese additions to promote improved performance. This paper focuses on the response of the first set of developmental alloys to neutron-irradiation and susceptibility to stress corrosion cracking. These cast materials may also have applications for different components in light water reactors. Results showed that all steels exhibited irradiation-induced hardening and a corresponding drop in ductility, as expected, although there is still considerable ductility in the irradiated samples. The cast steels all exhibited reduced hardening in comparison to a wrought reference steels, which may be related to a larger grain size. Higher nitrogen contents did not negatively influence irradiation performance. Regarding stress corrosion cracking susceptibility, the large difference in grain size limits the comparison between wrought and cast materials, and inclusions in a reference and archive cast alloy tests complicate analysis of these samples. Results suggest that the irradiated archive heat was more susceptible to cracking than the modified alloys, which may be related to the more complex microstructure. Further, the results suggest that the modified cast steel is at least as SCC resistant as wrought 316LN. The beneficial effect of nitrogen on the mechanical properties of the alloys remains after irradiation and is not

  2. Microstructure, corrosion and tribological and antibacterial properties of Ti-Cu coated stainless steel.

    Jin, Xiaomin; Gao, Lizhen; Liu, Erqiang; Yu, Feifei; Shu, Xuefeng; Wang, Hefeng

    2015-10-01

    A Ti-Cu coated layer on 316L stainless steel (SS) was obtained by using the Closed Field Unbalanced Magnetron Sputtering (CFUBMS) system to improve antibacterial activity, corrosion and tribological properties. The microstructure and phase constituents of Ti-Cu coated layer were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and glow discharge optical emission spectrometry (GDOES). The corrosion and tribological properties of a stainless steel substrate, SS316L, when coated with Ti-Cu were investigated in a simulated body fluid (SBF) environment. The viability of bacteria attached to the antibacterial surface was tested using the spread plate method. The results indicate that the Ti-Cu coated SS316L could achieve a higher corrosion polarization resistance and a more stable corrosion potential in an SBF environment than the uncoated SS316L substrate. The desirable corrosion protection performance of Ti-Cu may be attributable to the formation of a Ti-O passive layer on the coating surface, protecting the coating from further corrosion. The Ti-Cu coated SS316L also exhibited excellent wear resistance and chemical stability during the sliding tests against Si3N4 balls in SBF environment. Moreover, the Ti-Cu coatings exhibited excellent antibacterial abilities, where an effective reduction of 99.9% of Escherichia coli (E.coli) within 12h was achieved by contact with the modified surface, which was attributed to the release of copper ions when the Ti-Cu coatings are in contact with bacterial solution. PMID:26093948

  3. Effect of environmental factors of stress corrosion cracking behavior of turbine steel in pure water

    Slow Strain Rate Tests (SSRT) were carried out to investigate the effect of dissolved oxygen on stress corrosion cracking (SCC) susceptibility of 3.5NiCrMoV steels used in discs of low-pressure (LP) steam turbines in electric power generating plants. The influence of dissolved oxygen on cracking in water was studied; for this purpose, specimens were strained to fracture at 150 degree C in water environments with various amounts of dissolved oxygen. Also tests were conducted in aerated water at temperature of 50 ∼ 200 degree C and at various strain rates (5x10-8 ∼ 1x10-5 s-1). The maximum elongation of the turbine steel decreased with decreasing strain rate, and with increasing temperature. Dissolved oxygen significantly affected the SCC susceptibility of turbine steel in water. The increase of the SCC susceptibility of the turbine steel in a higher dissolved oxygen environment is due to the non protectiveness of the oxide layer of the turbine steel surface and the increase of corrosion current

  4. Hydrazino-methoxy-1,3,5-triazine Derivatives’ Excellent Corrosion Organic Inhibitors of Steel in Acidic Chloride Solution

    Ayman El-Faham

    2016-06-01

    Full Text Available The corrosion inhibition performance of 2-hydrazino-4,6-dimethoxy-1,3,5-tirazine (DMeHT, 2,4-dihydrazino-6-methoxy-1,3,5-triaizine (DHMeT, and 2,4,6-tridydrazino-1,3,5-triaizne (TH3 on steel corrosion in acidic media was examined using electrochemical techniques. The results showed 2,4-Ddihydrazino-6-methoxy-1,3,5-triaizine (DHMeT gave the best corrosion protection performance among the other hydrazino derivatives even at a low concentration of 25 ppm (95%. The number of hydrazino groups play an important role in the corrosion inhibition, where the two hydrazine groups increased the electrostatic interactions between the protonated tested compounds, the negatively charged steel surface resulted from the adsorption of the chloride anions, and the presence of the methoxy group made the compound more reliable for formation of film protection on the surface of steel through the lone pair of oxygen atoms. Electrochemical Impedance Spectroscopy (EIS measurements suggested that the corrosion process of steel in presence of the hydrazino-s-triazine derivatives (TH3, DMeHT and DHMeT were being controlled by the charge transfer reaction. Polarization curves indicated that the examined TH3, DMeHT and DHMeT behaved as mixed type inhibitors.

  5. Hydrazino-methoxy-1,3,5-triazine Derivatives' Excellent Corrosion Organic Inhibitors of Steel in Acidic Chloride Solution.

    El-Faham, Ayman; Osman, Sameh M; Al-Lohedan, Hamad A; El-Mahdy, Gamal A

    2016-01-01

    The corrosion inhibition performance of 2-hydrazino-4,6-dimethoxy-1,3,5-tirazine (DMeHT), 2,4-dihydrazino-6-methoxy-1,3,5-triaizine (DHMeT), and 2,4,6-tridydrazino-1,3,5-triaizne (TH₃) on steel corrosion in acidic media was examined using electrochemical techniques. The results showed 2,4-Ddihydrazino-6-methoxy-1,3,5-triaizine (DHMeT) gave the best corrosion protection performance among the other hydrazino derivatives even at a low concentration of 25 ppm (95%). The number of hydrazino groups play an important role in the corrosion inhibition, where the two hydrazine groups increased the electrostatic interactions between the protonated tested compounds, the negatively charged steel surface resulted from the adsorption of the chloride anions, and the presence of the methoxy group made the compound more reliable for formation of film protection on the surface of steel through the lone pair of oxygen atoms. Electrochemical Impedance Spectroscopy (EIS) measurements suggested that the corrosion process of steel in presence of the hydrazino-s-triazine derivatives (TH₃, DMeHT and DHMeT) were being controlled by the charge transfer reaction. Polarization curves indicated that the examined TH₃, DMeHT and DHMeT behaved as mixed type inhibitors. PMID:27258241

  6. Investigation of Stainless Steel Corrosion in Ultrahigh-Purity Water and Steam Systems by Surface Analytical Techniques

    Dong, Xia; Iacocca, Ronald G.; Bustard, Bethany L.; Kemp, Craig A. J.

    2010-02-01

    Stainless steel pipes with different degrees of rouging and a Teflon®-coated rupture disc with severe corrosion were thoroughly investigated by combining multiple surface analytical techniques. The surface roughness and iron oxide layer thickness increase with increasing rouge severity, and the chromium oxide layer coexists with the iron oxide layer in samples with various degrees of rouging. Unlike the rouging observed for stainless steel pipes, the fast degradation of the rupture disc was caused by a crevice corrosion environment created by perforations in the protective Teflon coating. This failure analysis clearly shows the highly corrosive nature of ultrapure water used in the manufacture of pharmaceutical products, and demonstrates some of the unexpected corrosion mechanisms that can be encountered in these environments.

  7. Effect of antimony(III) on carbon steel corrosion inhibition by molybdate in citric acid solution

    Molybdate is known as a good corrosion inhibitor of carbon steel (CS). But it cannot inhibit CS corrosion in citric acid solution at 85 °C. It has been observed that the presence of small concentration of Sb(III) along with MoO42- inhibits CS corrosion efficiently. The corrosion inhibition by MoO42- have been studied extensively by varying the concentration of Sb(III) and MoO42-. A critical concentration of MoO42- is required to passivate CS in acid medium in the presence of Sb(III). The study shows that molybdate forms a thin protective layer on CS surface in presence of Sb(III) which provides the corrosion inhibition. Inhibition property and the layer composition on CS surface have been studied by electrochemical and surface analytical techniques. The protective layer is found to be composed of both Mo and Sb and appears to be formed due to cathodic reduction of Mo6+ to Mo5+ and Mo4+ and anodic oxidation of Fe and Sb. (author)

  8. Influence of hydrogen on corrosion and stress induced cracking of stainless steel

    Kivisäkk, Ulf

    2010-01-01

    Hydrogen is the smallest element in the periodical table. It has been shown in several studies that hydrogen has a large influence on the corrosion and cracking behaviour of stainless steels. Hydrogen is involved in several of the most common cathode reactions during corrosion and can also cause embrittlement in many stainless steels. Some aspects of the effect of hydrogen on corrosion and hydrogen-induced stress cracking, HISC, of stainless steels were studied in this work. These aspects rel...

  9. Radiation-induced grain boundary segregation effect on stress corrosion cracking in steel

    Stress corrosion cracking of stainless steels 304L, 316 and 316L irradiated at 673 K up to the dose of 0.8 dpa is studied. It is shown that radiation-induced reduction of chromium content in the grain boundary results in corrosion cracking of the steels in water containing dissolved oxygen. Corrosion cracking in water with dissolved hydrogen occurs in the context of radiation-induced strengthening of the steel and change in its microstructure

  10. High temperature corrosion of boiler steels in hydrochloric atmosphere under oil shale ashes

    Highlights: • High temperature gaseous hydrochloric corrosion analysis of different boiler steels. • Influence on the corrosion of the presence of oil shale ashes and cyclic removing. • Empiric kinetic coherence equation and diagram for corrosion depth versus time. • Additional oxidation tests of all materials investigated. • Qualitative analysis of the present corrosion mechanisms. - Abstract: High temperature corrosion in power plants is a main breakdown criterion in boiler applications. This study is focused on the high-temperature corrosion resistance of several boiler steels used in Estonian power plants, which were experimentally tested in gaseous hydrochloric environment combined with Estonian oil shale ashes in a high temperature corrosion test up to 600 °C. Scanning electron microscopy supported by energy dispersive X-ray spectroscopy was used to reveal different corrosion mechanisms. Results indicate a strong dependence of the boiler steel corrosion to the present anions in the oil shale ash and their removal in the boiler

  11. Protective oxide coating on the surface of steel St20

    The authors investigated the stability of oxide coatings on the surface of pearlitic steel 20 at 90 degree C in an aqueous medium. The article examines the influence of the flow rate and of the presence of corrosion products of iron on the protective effect of the oxide coating. On the basis of the results of the investigations obtained with the aid of the radionuclides 59Fe, 54Mn, 137Cs the conclusion is reached that the oxide coating is not restored and does not peel off. The assumption is voiced that a layer of hydroxide forms between the metal and the oxide coating

  12. Long term corrosion resistance of alumina forming austenitic stainless steels in liquid lead

    Highlights: • Alumina forming austenitic stainless steels (AFA) were exposed to lead at 550 °C. • The influence of Al addition and Ni content was evaluated. • The low Ni (14 wt.%) AFA formed a thin protective Al rich oxide on its surfaces. • 17% ferrite was formed in the 14Ni AFA alloy as a result of the one year exposure. - Abstract: Alumina forming austenitic steels (AFA) and commercial stainless steels have been exposed in liquid lead with 10−7 wt.% oxygen at 550 °C for up to one year. It is known that chromia forming austenitic stainless steels, such as 316L and 15–15 Ti, have difficulties forming protective oxides in liquid lead at temperatures above 500 °C, which is confirmed in this study. By adding Al to austenitic steels, it is in general terms possible to increase the corrosion resistance. However this study shows that the high Ni containing AFA alloys are attacked by the liquid lead, i.e. dissolution attack occurs. By lowering the Ni content in AFA alloys, it is possible to achieve excellent oxidation properties in liquid lead. Following further optimization of the microstructural properties, low Ni AFA alloys may represent a promising future structural steel for lead cooled reactors

  13. Corrosion and cathodic protection of buried pipes: study, simulation and application of solar energy

    Cathodic protection is intensively used on steel pipes in petroleum and gas industries. It is a technique used to prevent corrosion which transforms the whole pipe into a cathode of a corrosion cell. Two types of cathodic protection systems are usually used: 1) the galvanic protection systems which use galvanic anodes, also called sacrificial anodes being electrochemically more electronegative than the structure to be protected and 2) the imposed current systems, which through a current generator will deliver a direct current from the anode to the structure to be protected. The aim of this work is to design a cathodic protection system of a pipe by imposed current with auxiliary electric solar energy. (O.M.)

  14. Electrochemical corrosion behavior of stainless steel irradiated in FBR

    A cooperative research on the evaluation of fracture behaviors of neutron irradiated materials has been initiated in 1991 by the Japan Atomic Energy Research Institute (JAERI) and the Power Reactor and Nuclear Fuel Development Corporation (PNC). The research program includes a study of stress corrosion cracking (SCC) of the wrapper tube material of fuel assembly irradiated in the experimental fast reactor 'JOYO'. The program is related with a research activity on the irradiation assisted stress corrosion cracking (IASCC) at JAERI. To investigate the SCC behavior and to pursue its mechanism, knowledges about a corrosion behavior of the material are required. Therefore corrosion tests were performed on the irradiated material by employing electrochemical technique. On the wrapper tube material of type 316 stainless steel irradiated in 'JOYO' up to a neutron fluence of 7 x 1022 n/cm2 (E > 0.2 MeV) at about 400degC, the electrochemical potentiokinetic reactivation (EPR) test and the potentiostatic electrolytic test were carried out in the hot laboratory of JAERI. By EPR test a degradation of corrosion resistance due to the irradiation was detected. By the other test a possibility of grain boundary segregation of impurity elements was shown. (author)

  15. Mass transfer of stainless steel corrosion products in sodium

    Mass transfer of stainless steel corrosion products (CP) in sodium coolant circuits in the absence of chemical interaction of impurities in sodium as well as in the case of interaction of steel components with oxygen and hydrogen is investigated. The mathematical models of CP mass transfer in pure sodium and in that with increased oxygen content are elaborated. The values of constants using in description of the processes under consideration are refined in experiments. The integral model of CP mass transfer applied to non-isothermal circulation sodium circuit is developed. Calculated data on steel components transfer in BN-600 primary coolant circuit are obtained. Parametric calculations for the model taking into account the deposit formation on the channel surface are conducted. Distribution of CP flow density on walls along the channel length are obtained

  16. Study of corrosion resistance of chromium-nickel steel in calcium - hypochlorite solution. Part 1. Steels uranus b6

    Tošković D.; Rajković Miloš B.; Stanojević D.

    2002-01-01

    Corrosion resistance of Cr - Ni (special steels) specimen is tested by electrochemical methods, numerical method of linear polarization and polarization resistance method in calcium-hypochlorite (Ca(OCl)2) solutions. With increasing of Ca(OCl)2 concentration, pH value of the solution increases, as well as active chlorine concentration and corrosion activity of the medium. According to the quantitative method of the corrosion resistance determination it can be concluded that the steels tested ...

  17. Corrosion of nickel alloys and stainless steels in polluted or confined PWR environments

    This document addresses the issue of corrosion of materials used in PWR nuclear reactors, notably in steam generators which have been particularly affected by this kind of degradation due to a progressive accumulation of impurities. The authors first present the different materials used in secondary circuit and in auxiliary circuits of PWRs: carbon steels and low alloyed steels, nickel alloys, stainless steels, and other materials. They discuss the degradation of steam generator tubes by corrosion: corrosion environments, types of corrosion (wastage, pitting, intergranular stress corrosion cracking), and influence of the environment and of the microstructure. They also propose a brief overview of modelling efforts in the case of the 600 alloy, and indicates measures to mitigate the tube degradation by corrosion (water treatment, better design of steam generators and secondary circuit, improvement of corrosion resistance). The next part addresses the degradation by stress corrosion cracking of stainless steels in polluted environments in PWRs reactors: return on experience, stress corrosion cracking in media contaminated by impurities (intergranular corrosion of sensitized or work hardened steels, transgranular corrosion by chloride ions, corrosion by diluted sulphate + chloride, corrosion in concentrated boric acid solutions)

  18. Corrosion of CrN-coated steels in liquid Pb-Bi

    Corrosion tests of CrN-coated steels were conducted in liquid lead-bismuth (Pb-Bi) at 450degC and 550degC for 3000 h to investigate the applicability of CrN coating to a liquid Pb-Bi environment. CrN coatings on F82H (Fe-8Cr-2W-0.3V-0.04Ta-0.1C) and 316SS exhibited good compatibility in liquid Pb-Bi during corrosion test at 450degC. The CrN coating layer suffered heavy damage such as cracking and spalling, and showed no effectiveness as a protective layer in corrosion test at 550degC. Nickel and chromium in 316SS dissolved into Pb-Bi through the damaged coating layer at 550degC. It is considered that stresses caused by the difference of thermal expansion coefficient between CrN and steels led to cracking and spalling of the CrN coating through corrosion attack by liquid Pb-Bi at 550degC. (author)

  19. Evaluation of Corrosion Resistance on Al-Cr Coated Stainless Steel Separator for MCFC at Anode Side

    Yoon, J.S.; Bae, I.S.; Park, H.H. [Korea Research Institute of Rare Materials, Sunchon (Korea); Lee, M.H. [Kwangyang College, Kwangyang (Korea); Yoon, D.J. [Hanlyo University, Kwangyang (Korea); Kim, B.I. [Sunchon National University, Sunchon (Korea)

    2003-02-01

    In order to evaluate the corrosion resistance at the anode side separator for molten carbonate fuel cell, STS316 and SACC-STS316 (chromium and aluminum were simultaneously deposited by diffusion into STS316 austenitic stainless steel substrate by pack-cementation process) were applied as the separator material. In case of STS316, corrosion proceeded via three steps ; a formation step of corrosion product until stable corrosion product, a protection step against corrosion until breakaway occurs, a advance step of corrosion after breakaway. Especially, STS316 would be impossible to use the separator without suitable surface modification because of rapid corrosion rate after formation of corrosion product, occurs the severe problem on stability of cell during long-time operation. Whereas, SACC-STS316 was showed more effective corrosion resistance than the present separator, STS316 due to the intermetallic compound layer such as NiAl, Ni3Al formed on the surface of STS316 specimen. And it is anticipated that, in order to use SACC-STS316 alternative separator at the anode side, coating process, which can lead to dense coating layer, has to be developed, and by suitable pre-treatment before using it, very effective corrosion resistance will be achieved. (author). 15 refs., 9 figs.

  20. Corrosion Behavior of Austenitic and Duplex Stainless Steels in Lithium Bromide

    Ayo Samuel AFOLABI

    2009-07-01

    Full Text Available The corrosion behavior of austenitic and duplex stainless steels in various concentrations of lithium, bromide solution was investigated by using the conventional weight loss measurement method. The results obtained show that corrosion of these steels occurred due to the aggressive bromide ion in the medium. Duplex stainless steel shows a greater resistance to corrosion than austenitic stainless steel in the medium. This was attributed to equal volume proportion of ferrite and austenite in the structure of duplex stainless steel coupled with higher content of chromium in its composition. Both steels produced electrochemical noise at increased concentrations of lithium bromide due to continuous film breakdown and repair caused by reduction in medium concentration by the alkaline corrosion product while surface passivity observed in duplex stainless steel is attributed to film stability on this steel.

  1. Fabrication of high nitrogen austenitic stainless steels with excellent mechanical and pitting corrosion properties

    Hua-bing Li; Zhou-hua Jiang; Yang Cao; Zu-rui Zhang

    2009-01-01

    18Cr18Mn2Mo0.9N high nitrogen austenitic stainless steel exhibits high strength and good ductility at room temperature. The steel shows typical duc-tile-brittle transition behavior and excellent pitting corrosion resistance properties.

  2. Carbon steel protection in G.S. [Girldler sulphide] plants: Pt. 7

    In order to protect carbon steel towers and piping of a GS experimental heavy water plant against corrosion produced by the action of aqueous solutions of hydrogen sulphide, a method, elsewhere published, was developed. Carbon steel exposed to saturated aqueous solutions of hydrogen sulphide forms iron sulphide scales. In oxygen free solutions, evolution of corrosion follows the sequence mackinawite → cubic ferrous sulphide → troilite → pyrrotite → pyrite. Scales formed by pyrrotite and pyrite are the most protective layers (these are obtained at 130 deg C, 2 MPa for a period of 14 days). During a plant shutdown procedures, the carbon steel protected with those scales is exposed to water and highly humid air; under such conditions oxidation is unavoidable. Later, treatment in plant conditions does not regenerate scales because the composition of regenerated scales involves more soluble iron sulphides such as mackinawite and troilite. Therefore, it is not recommendable to expose the protective scales to atmospherical conditions. (Author)

  3. Microbially influenced corrosion of 303 stainless steel by marine bacterium Vibrio natriegens: (II) Corrosion mechanism

    Yin Yansheng, E-mail: yys2006@ouc.edu.cn [Institute of Ocean Materials and Engineering, Shanghai Maritime University, Shanghai 200135 (China); Cheng Sha [Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100 (China); Chen Shougang, E-mail: sgchen@ouc.edu.cn [Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100 (China); Tian Jintao; Liu Tao; Chang Xueting [Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100 (China)

    2009-04-30

    Electrochemical techniques (electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves) and surface analysis (scanning electron microscopy (SEM)) were carried out to determine the possible mechanism of the microbially influenced corrosion of 303 stainless steel (303 SS) by marine bacterium Vibrio natriegens (V. natriegens). In order to clarify the mechanism, 303 SS coupons were immersed in four different mediums. EIS results were interpreted with different equivalent circuits to model the physicoelectric characteristics of the electrode/biofilm/solution interface. The results showed that N{sub 2}-fixation actually promoted the corrosion of 303 SS; however, the influence of the produced NH{sub 3} was negligible. It can be speculated that the electron transfer and/or the nitrogenase catalyzing the process may influence the corrosion.

  4. Microbially influenced corrosion of 303 stainless steel by marine bacterium Vibrio natriegens: (II) Corrosion mechanism

    Electrochemical techniques (electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves) and surface analysis (scanning electron microscopy (SEM)) were carried out to determine the possible mechanism of the microbially influenced corrosion of 303 stainless steel (303 SS) by marine bacterium Vibrio natriegens (V. natriegens). In order to clarify the mechanism, 303 SS coupons were immersed in four different mediums. EIS results were interpreted with different equivalent circuits to model the physicoelectric characteristics of the electrode/biofilm/solution interface. The results showed that N2-fixation actually promoted the corrosion of 303 SS; however, the influence of the produced NH3 was negligible. It can be speculated that the electron transfer and/or the nitrogenase catalyzing the process may influence the corrosion.

  5. Long-Term Anti-Corrosion Performance of a Conducting Polymer-Based Coating System for Steels

    Pan, Tongyan; Yu, Qifeng

    2016-06-01

    The long-term durability of a two-layer coating system was evaluated by two accelerated corrosion tests, i.e., the ASTM B117 Salt spray test and the ASTM D5894 Cyclic salt fog/UV exposure test, and a series of surface analyses. The coating system was developed for protecting structural steels from corrosion, including a functional primer made of intrinsically conducting polymer (ICP) and a protective topcoat. The standard pull-off test per ASTM D4541 was employed for characterizing the adhesion of the coating systems to substrate, aided by visual examination of the surface deterioration of the samples. The ICP-based systems demonstrated superior long-term anti-corrosion capacity when a polyurethane topcoat is used. The ICP-based primer made of a waterborne epoxy gave poorer anti-corrosion performance than the ICP-based primer made of regular non-waterborne epoxy, which can be attributed to the lower adhesion the waterborne epoxy demonstrated to the substrate surface. The zinc-rich control systems showed good anti-corrosion durability; however, they may produce excessive oxidative products of zinc to cause coating delamination. Based on the test results, the two-layer coating system consisting of an ICP-based primer and a polyurethane topcoat outperforms the conventional zinc-rich coating systems for corrosion protection of steels.

  6. Stress corrosion of unalloyed steels in geological storage conditions

    The concept retained for high level and years living radioactive waste disposal is the underground storage. It is then necessary to know the behaviour in time (about 10000 years) of the different constituent elements of the containment. The storage site chosen is the Bures' ones, presenting a clay formation at 600 m of depth. Each compartment is separated of a sufficient distance in order to profit of the thermal dispersion effect in the rock for optimizing the cooling of the package. In this work, has been used an unalloyed steel sur-container. The aim is to understand the resistance of the material under corrosion and loading, and particularly the stress corrosion which is a particular case of cracking assisted by environment. The material studied is a weld of two unalloyed steels obtained by electron beam. Slow traction tests have been carried out in an autoclave in the following experimental conditions: interstitial water in equilibrium with a helium-CO2 mixture 5.4 per thousand under 50 bar and at a temperature of 90 C. The results show an influence of the hydrogen corrosion on the mechanical behaviour of the material and particularly a decrease of the size of the reduction in area, which is practically unexisting in the case of the melted zone. These results are explained into details. (O.M.)

  7. Stress corrosion cracking of austenitic stainless steel core internal weld

    Microstructural analyses by several advanced metallographic techniques were conducted on austenitic stainless steel mockup and core shroud welds that cracked in boiling water reactors. Contrary to previous beliefs, heat-affected zones of the cracked Type 304L as well as 304 SS core shroud welds and mockup shielded-metal-arc welds were free of grain-boundary carbides, which shows that core shroud failure cannot be explained by classical intergranular stress corrosion cracking. Neither martensite nor delta-ferrite films were present on grain boundaries. However, as a result of exposure to weld fumes, the heat-affected zones of the core shroud welds were significantly contaminated by oxygen and fluorine which migrate to grain boundaries. Significant oxygen contamination seems to promote fluorine contamination and suppress thermal sensitization. Results of slow-strain-rate tensile tests indicate also that fluorine exacerbate the susceptibility of irradiated steels to intergranular stress corrosion cracking. These observations, combined with previous reports on the strong influence of weld flux, indicate that oxygen and fluorine contamination and fluorine-catalyzed stress corrosion play a major role in cracking of core shroud welds

  8. Microbially influenced corrosion of stainless steel by manganese oxidizing microorganisms

    Linhardt, P. [Technische Universitaet Wien, Technische Versuchs- und Forschungsanstalt (TVFA), Karlsplatz 13, 1040 Wien (Austria)

    2004-03-01

    Based on the corrosion behaviour of stainless steels in fresh water and on the electrochemical properties of higher manganese oxides, the mechanism ''Microbially influenced corrosion by manganese oxidizing microorganisms'' (MIC by MOMOs) is presented as the consequence of biomineralized manganese oxides in contact with the metal. Localized corrosion may develop at elevated but normally undercritical chloride concentration in the water. The mechanism was found useful in the analysis of certain cases of unexpected failure of stainless steel in fresh water. (Abstract Copyright [2004], Wiley Periodicals, Inc.) [German] Ausgehend vom Korrosionsverhalten nichtrostender Staehle in Suesswasser und den elektrochemischen Eigenschaften hoeherer Manganoxide wird der Mechanismus ''Mikrobiell beeinflusste Korrosion durch manganoxidierende Mikroorganismen'' als die Folge des Kontaktes von biomineralisiertem Braunstein mit dem metallischen Werkstoff beschrieben. Unter diesen Bedingungen kann Lokalkorrosion bei Chloridkonzentrationen im Wasser entstehen, die normalerweise als unkritisch angesehen werden. Der Mechanismus hat sich bei der Schadensanalyse bestimmter, unerwarteter Korrosionsfaelle bewaehrt. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  9. Mechanism of pitting corrosion prevention by nitrite in carbon steel exposed to dilute salt solutions. 1998 annual progress report

    'The overall goal of this project is to develop a fundamental understanding of the role of nitrite in preventing the breakdown of protective oxide(s) on carbon steel and the onset of pitting. Pitting corrosion of carbon steel exposed to dilute alkaline salt solutions can be induced by nitrate, sulfate, and chloride ions and is prevented by sufficient concentration of nitrite. A significant example of this material/electrolyte system is the storage and processing of DOE''s high-level radioactive liquid waste in carbon steel tanks. Added nitrite in the waste has a considerable downstream impact on the immobilization of the waste in a stable glass form. Waste tank integrity and glass production efficiency may benefit from the fundamental understanding of nitrite''s role in preventing pitting. This report summarizes progress after approximately six months of effort in this three-year EMSP project. Initial experimental and theoretical work has focused on the electrochemical behavior of carbon steel in simplified non-radioactive solutions that simulate complex dilute radioactive waste solutions. These solutions contain corrosion-inducing species such as nitrate and chloride and the corrosion-inhibiting nitrite at moderately alkaline pHs. The electrochemical behavior of interest here is that of the open-circuit potential of the steel specimen at equilibrium in the experimental electrolyte and the measures of the steel''s passivity and passivity breakdown.'

  10. Investigation of the corrosion fatigue behaviour of turbineblade steels in the region of initial steam condensation

    The fact that a large proportion of the total number of turbine failures is due to blade damage, particularly in the region of initial steam condensation, led to comprehensive investigations of the behaviour of 12/13% chromium steels. 17% Cr-4% Ni steel, duplex stainless steels and titanium alloys with regard to pitting corrosion and corrosion fatigue. The corrosion fatigue strength of these materials after a specific number of cycles in media representative of operating conditions is dependent principially on whether or not pitting corrosion and/or hydrogen-induced crack propagation along cleavage planes occur during dynamic loading in the relevant environment. With optimisation of heat treatment, duplex stainless steels free from copper, 17% Cr-4% Ni steel and the titanium alloy, TiAl6V4 offer better corrosion fatigue behaviour than the 12/13% chromium steels, performance improving in the order as listed. (orig.)

  11. An electroless plating film of palladium on 304 stainless steel and its excellent corrosion resistance

    An uniform palladium film on 304 stainless steel was obtained by electroless plating. Scanning electronic microscopy, X-ray photoelectron spectroscopy, weight loss tests and electrochemical measurements were used to character the properties of the film. The palladium plated stainless steel samples showed excellent corrosion resistance in strong reductive corrosion mediums. In boiling dilute sulfuric acid solutions and boiling acetic/formic acids, corrosion rates of palladium plated 304 stainless steel samples were 3 or 4 orders of magnitude lower than the original 304 stainless steel samples. In solutions with NaCl concentration less that 0.1%, the palladium plated samples also showed better corrosion resistance. The function of palladium film on stainless steel is to raise the electrode potential and promote passivation of the steel in strong corrosive environments

  12. Coating Prospects in Corrosion Prevention of Aluminized Steel and Its Coupling with Magnesium

    Sun, Fuyan

    In this study, a plasma electrolytic oxidation (PEO) process was used to form oxide coating on aluminized steel, heated aluminized steel and magnesium. A potentiodynamic polarization corrosion test was employed to investigate the general corrosion properties. Galvanic corrosion of steel samples and magnesium samples was studied by zero resistance ammeter (ZRA) tests and boiling tests. Scanning electron microscopy (SEM) and EDS were used to investigate the coating microstructure and the coating/substrate interface. In general, the PEO coatings on all three substrate can help prevent general corrosion. 6-min coated magnesium with unipolar current mode performs best in most galvanic couplings for preventing both general corrosion and galvanic corrosion. Factors which could influence galvanic corrosion behaviors of tested samples were discussed based on area ratios of anode/cathode and cell potential driving force during the ZRA corrosion tests and boiling tests.

  13. Inhibition of mild steel corrosion using Jatropha Curcas leaf extract

    OLORUNFEMI MICHAEL AJAYI

    2014-05-01

    Full Text Available Jatropha Curcas leaf was investigated as a green inhibitor on the degradation of mild steel in 4 M HCl and 4 M H2SO4 aqueous solutions using gasometric technique. Mild steel coupons of dimension 2 × 1.5 cm were immersed in test solutions of uninhibited acid and also those with extract concentrations of 4 ml, 6 ml, 8 ml and 10 ml at 30 oC, for up to 30 minutes. The results showed that as the concentration of the extract increases, there was reduction in the corrosion rate. As the extract concentration increased from 4 ml to 10 ml at 30 minutes exposure, the volume of hydrogen gas evolved decreased from 19.1 cm3 to 11.2 cm3 in H2SO4 medium, while it reduced to 5 cm3 from 9 cm3 in HCl medium. Also, the metal surface-phytoconstituent interaction mechanism showed that 6 minutes is the best exposure time for the adsorption of the extract in both acidic media. The Jatropha Curcas leaf extract was adsorbed on the mild steel surface to inhibit corrosion, while the experimental data obtained at 30 minutes exposure in both acidic media were well fitted with the Langmuir adsorption isotherm. Hence, Jatropha Curcas leaf extract is a good and safe inhibitor in both acidic solutions.

  14. Corrosion inhibition of steel in sulphuric acid by pyrrolidine derivatives

    Novel corrosion inhibitors, namely 1-{2-[(2-hydroxyethyl)thio]ethyl}pyrrolidin-2-one (P5) and {[2-(2-oxopyrrolidin-1-yl)ethyl]thio}acetic acid (P4), were synthesised and tested as corrosion inhibitors for steel in 0.5 M H2SO4. The effects of P4 and P5 are also compared to their initial reactants 1-vinylpyrrolidin-2-one (P1), 2-mercaptoethanol (P2) and mercaptoacetic acid (P3). The study was carried out by weight loss measurements, potentiodynamic polarisation, linear polarisation resistance (R p) and electrochemical impedance spectroscopy (EIS) methods. The inhibition efficiency increases with the concentration of P5 to attain 89% at 5 x 10-3 M. We note good agreement between the various methods explored. Polarisation measurements show also that the pyrrolidones act essentially as cathodic inhibitors. The cathodic curves indicate that the reduction of proton at the steel surface is an activating mechanism. P4 and P5 adsorb on the steel surface according to Langmuir adsorption model. Effect of temperature is also studied in the 298-353 K range. Efficiency is explained by the theoretical studies

  15. Structure and mechanical properties of the three-layer material based on a vanadium alloy and corrosion-resistant steel

    Nikulin, S. A.; Rozhnov, A. B.; Nechaikina, T. A.; Rogachev, S. O.; Zavodchikov, S. Yu.; Khatkevich, V. M.

    2014-10-01

    The quality of three-layer pipes has been studied; they are manufactured by hot pressing of a three-layer assembly of tubular billets followed by forging and cold rolling. The operating core is made from a V-4Ti-4Cr alloy. The protective claddings are made from corrosion-resistant steels of two grades, 08Kh17T and 20Kh13. The results of investigation into the structure and microhardness of the junction zone of steel and the vanadium alloy, which includes a contact zone and a transition diffusion layer, are reported. The 08Kh17T steel is shown to be a preferred cladding material.

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

    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.

  17. Prediction of External Corrosion for Steel Cylinders--2007 Report

    Schmoyer, Richard L [ORNL

    2008-01-01

    Depleted uranium hexafluoride (DUF{sub 6}) is stored in over 62,000 containment cylinders at the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and at the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. Over 4,800 of the cylinders at Portsmouth were recently moved there from the East Tennessee Technology Park (ETTP) in Oak Ridge, Tennessee. The cylinders range in age up to 56 years and come in various models, but most are 48-inch diameter 'thin-wall'(312.5 mil) and 'thick-wall' (625 mil) cylinders and 30-inch diameter '30A' (including '30B') cylinders with 1/2-inch (500 mil) walls. Most of the cylinders are carbon steel, and they are subject to corrosion. The United States Department of Energy (DOE) manages the cylinders to maintain them and the DUF{sub 6} they contain. Cylinder management requirements are specified in the System Requirements Document (LMES 1997a), and the activities to fulfill them are specified in the System Engineering Management Plan (LMES 1997b). This report documents activities that address DUF{sub 6} cylinder management requirements involving measuring and forecasting cylinder wall thicknesses. As part of these activities, ultrasonic thickness (UT) measurements are made on samples of cylinders. For each sampled cylinder, multiple measurements are made in an attempt to find, approximately, the minimum wall thickness. Some cylinders have a skirt, which is an extension of the cylinder wall to protect the head (end) and valve. The head/skirt interface crevice is thought to be particularly vulnerable to corrosion, and for some skirted cylinders, in addition to the main body UT measurements, a separate suite of measurements is also made at the head/skirt interface. The main-body and head/skirt minimum thickness data are used to fit models relating minimum thickness to cylinder age, nominal thicknesses, and cylinder functional groups defined in terms of plant site, storage yard

  18. Pulsed laser deposition of alumina coating for corrosion protection against liquid uranium

    Alumina coatings find wide applications as tribological coatings and as corrosion protective coatings for structural materials against chemical attack. We have investigated alumina coatings deposited on Stainless Steel (SS) substrates via pulsed laser deposition (PLD) technique. Characterization tests performed on these coatings including their compatibility with liquid uranium suggests alumina to be a potential candidate as a coating material for handling and containment of liquid uranium. We present here results of our detailed parametric study including dependence of average mass removal rate on laser fluence and ablation geometry and average deposition efficiency during PLD. These measurements provide vital inputs facilitating proper choice of process parameters for PLD runs. Deposited coatings have been characterized in terms of their microstructure, surface profile, adhesion to substrate, crystalline phase and corrosion resistance against liquid uranium. Our PLD based alumina coatings have shown a high degree of compaction and excellent corrosion resistance to molten uranium even upto a temperature of 1165 °C. - Highlights: • Alumina films deposited on stainless steel via pulsed laser deposition (PLD) technique. • PLD alumina films investigated as potential corrosion protective coatings. • Deposited coatings have been characterized in terms of their microstructure and crystalline phase. • Corrosion resistance of coatings against liquid uranium was tested. • Results suggest PLD alumina films have a promising potential for containment of molten uranium

  19. Flow accelerated corrosion of carbon steel piping in nuclear power plants

    Flow accelerated corrosion (FAC) is a process whereby the normally protective oxide layer on carbon or low alloy steel dissolved into a stream of flowing water resulting in increasing the corrosion rate. Major influencing factors that affect the FAC are flow velocity, temperature, pH, dissolved oxygen concentration, and steel composition. The experimental study described in this paper was focused on evaluating the FAC behavior of carbon steel according to environment conditions. Feasibility tests for the mitigation method against the FAC were also carried out with controlling the water chemistry and with applying the magnetic field. A high temperature rotating cylinder electrode (HTRCE) and a water chemistry control system was developed to perform the electrochemical test in high temperature water environments. The main design concept of HTRCE is to assure stable operation of working electrode in a severe environment, to insulate electrode housing except working electrode surface against external fluid, and to extract corrosion parameter from the rotating cylinder to outside of the autoclave safely. The electrochemical corrosion potential (ECP) and current density were measured as a function of temperature and rotating speed using polarization monitoring. ECP values dropped at a rate of -1.51 mV/.deg. C above 150 .deg. C, which may be come from the formation of magnetite on the steel surface. With increasing rotation of the RCE, the ECP shifted upward in all temperature ranges. This shift may be attributed to the diffusion enhancement of the oxidizing agents in the rapidly flowing of fluid. From the velocity exponent of the cathodic half-cell current density on the steel surface, it was evident that a mass transfer process first dominated the corrosion reaction at 150 .deg. C, and then an activation process partly controlled the corrosion kinetics with increasing temperature. From the results of corrosion experiment at high temperature water, HTRCE has been proved

  20. Cladding of pressure vessel steel with corrosion resistant filler material

    Pressure vessels are often on the inside clad with corrosion resistant material. Of the various cladding processes surfacing by welding has proved to be most useful, especially for large thick-walled pressure vessels. Submerged arc welding with strip electrode is the most common method. Rather promising results have also been obtained by plasma hot wire welding. In general, Nb-alloyed austenitic stainless steel, over-alloyed with Cr and Ni, is used as filler material. Henceforth, also nickel alloys, e.g. Inconel 600, are used. The surfacing is made in one or several layers, following the requirements on the clad surface and the welding process used. The most dangerous welding defects in the surface are various types of cracks. The corrosion resistance of the cladding can show rather high local variations, depending on the composition of the filler material and various welding process factors. It is proved that the surface layer comparises areas with low chromium martensite. To ensure the corrosion resistance of the cladding, the generation of low-chromium martensite must be prevented by using suitable welding parameters, welding equipment and filler metal. It is also possible to eliminate the negative influence on the corrosion resistance from the low-chromium martensite, e.g. by welding in two layers. In the case of the high demands on quality a welding procedure test should always be made prior to production welding.(author)

  1. Ceria based protective coatings for steel interconnects prepared by spray pyrolysis

    Szymczewska, Dagmara; Molin, Sebastian; Chen, Ming;

    2014-01-01

    Stainless steels can be used in solid oxide fuel/electrolysis stacks as interconnects. For successful long term operation they require protective coatings, that lower the corrosion rate and block chemical reactions between the interconnect and adjacent layers of the oxygen or the hydrogen electro...... to deposit thin (~400 nm), continuous CeO2 layers on Crofer 22 APU steel substrates. Influence of the deposition parameters on layer quality is elucidated in this work....

  2. Corrosion inhibition of steel in sulfuric acidic solution by the Chenopodium Ambrosioides Extracts

    L. Bammou

    2014-10-01

    Full Text Available The influence of natural occurring extract of Chenopodium Ambrosioides (CAE on the corrosion inhibition of carbon steel in sulfuric acid solution is studied by the weight loss method, potentiodynamic polarization and impedance spectroscopy (EIS measurements. The experimental results reveal that extract has a good inhibiting effect on the metal tested in 0.5 M H2SO4 solution. The protection efficiency increases with increasing inhibitor concentration to attain 94% at 4 g/l. Potentiodynamic polarization studies clearly reveal that it acts essentially as a cathodic inhibitor. EIS results show that the change in the impedance parameters (Rt and Cdl with concentration of extract of Chenopodium Ambrosioides is indicative of the adsorption of molecules leading to the formation of a protective layer on the surface of carbon steel. The efficiency decreases with temperature. The adsorption of Chenopodium Ambrosioides extract is found to obey the Langmuir adsorption isotherm. The activation energies and enthalpies of the corrosion process of carbon steel in acidic medium were determined.

  3. Interaction of inhibitors with corrosion scale formed on N80 steel in CO{sub 2}-saturated NaCl solution

    Liu, D. [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Hubei Key Laboratory of Materials Chemistry and Service Failure, Wuhan (China); School of Chemical Engineering and Pharmacy, Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan (China); Qiu, Y.B.; Guo, X.P. [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Hubei Key Laboratory of Materials Chemistry and Service Failure, Wuhan (China); Tomoe, Y.; Bando, K. [Japan Oil, Gas and Metals National Corporation, The Former Japan National Oil Corporation, Hamada, Mihama-ku, Chiba-City, Chiba (Japan)

    2011-12-15

    The performance of the selected inhibitors, including thioglycolic acid (TGA), diethylenetriamine (DETA), and naphthene acid imidazolines (IM), on the bare surface of N80 steel and its scaled surface pre-corroded in CO{sub 2}-saturated 1%NaCl solution was investigated by weight-loss method, electrochemical measurements using rotating cylinder electrode and surface analytical methods (SEM, XRD, and EPMA). The results indicate that there is a remarkable difference in inhibition efficiency of inhibitors on the N80 steel with and without pre-corrosion scale. The synergistic effect between inhibitors and corrosion scale not only depends on the size of inhibitor molecules, but also depends on the interaction of the inhibitor with the corrosion scale. It shows that IM and DETA have a good positive synergistic effect with the corrosion scale formed on N80 steel, although DETA has no inhibition efficiency for bare N80 steel, which can easily enter into the apertures of the corrosion scale, and block the active sites on the metal surface and the diffusion routeways of the reactant so as to depress the corrosion of the substrate metal. While TGA shows excellent inhibition efficiency on bare N80 steel, but it has an antagonistic effect with the corrosion scale although it has a small molecular weight as well as DETA, because TGA can dissolve corrosion scale and break its integrality and protectiveness performance. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Interaction between corrosion crack width and steel loss in RC beams corroded under load

    This paper presents results and discussions on an experimental study conducted to relate the rate of widening of corrosion cracks with the pattern of corrosion cracks as well as the level of steel corrosion for RC beams (153 x 254 x 3000 mm) that were corroded whilst subjected to varying levels of sustained loads. Steel corrosion was limited to the tensile reinforcement and to a length of 700 mm at the centre of the beams. The rate of widening of corrosion cracks as well as strains on uncracked faces of RC beams was constantly monitored during the corrosion process, along the corrosion region and along other potential cracking faces of beams using a demec gauge. The distribution of the gravimetric mass loss of steel along the corrosion region was measured at the end of the corrosion process. The results obtained showed that: the rate of widening of each corrosion crack is dependent on the overall pattern of the cracks whilst the rate of corrosion is independent of the pattern of corrosion cracks. A mass loss of steel of 1% was found to induce a corrosion crack width of about 0.04 mm.

  5. Environmental factors affecting the corrosion behaviour of reinforcing steel. VI. Benzotriazole and its derivatives as corrosion inhibitors of steel

    Highlights: • The rate of oxide film repair follows a direct logarithmic law. • The inhibition efficiency depend on Cl− and the organic additives concentrations. • Benzotriazoles inhibit pitting corrosion by way of adsorption. • ΔG°ads values for organic additives reveal a chemisorption mechanism. - Abstract: Benzotriazole and some of its derivatives cause inhibition of corrosion of reinforcing steel in saturated naturally aerated Ca(OH)2 solutions contaminated by Cl−. The inhibition efficiency of these compounds depends on both the inhibitor type and concentration, as well as, on the chloride ions content. Inhibition by these compounds is assumed to take place through the formation of iron-chloro-benzotriazoles complexes and/or the adsorption of the deprotonated species on the steel surface according to Langmuir’s isotherm. The thermodynamic parameters Kads and ΔG°ads for the adsorption process are calculated and discussed. Benzotriazoles shift the pitting corrosion potential into the noble direction accounting for increased resistance to pitting

  6. Corrosion and Corrosion Inhibition of High Strength Low Alloy Steel in 2.0 M Sulfuric Acid Solutions by 3-Amino-1,2,3-triazole as a Corrosion Inhibitor

    El-Sayed M. Sherif

    2014-01-01

    Full Text Available The corrosion and corrosion inhibition of high strength low alloy (HSLA steel after 10 min and 60 min immersion in 2.0 M H2SO4 solution by 3-amino-1,2,4-triazole (ATA were reported. Several electrochemical techniques along with scanning electron microscopy (SEM and energy dispersive X-ray (EDS were employed. Electrochemical impedance spectroscopy indicated that the increase of immersion time from 10 min to 60 min significantly decreased both the solution and polarization resistance for the steel in the sulfuric acid solution. The increase of immersion time increased the anodic, cathodic, and corrosion currents, while it decreased the polarization resistance as indicated by the potentiodynamic polarization measurements. The addition of 1.0 mM ATA remarkably decreased the corrosion of the steel and this effect was found to increase with increasing its concentration to 5.0 mM. SEM and EDS investigations confirmed that the inhibition of the HSLA steel in the 2.0 M H2SO4 solutions is achieved via the adsorption of the ATA molecules onto the steel protecting its surface from being dissolved easily.

  7. Steel Corrosion Inhibition by Acid Garlic Essential Oil as a Green Corrosion Inhibitor a nd Sorption Behavior

    Afia, L.; Benali, O.; Salghi, R.; Ebenso, Eno E.; Jodeh, S.; Zougagh, M.; Hammouti, B.

    2014-01-01

    The aim of this work was to investigate the inhibition effect of acid garlic essential oil (GO oil) as an inhibitor on the corrosion of carbon steel in a 1M HCl solution at different temperatures by weight loss,electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods. The GO oil acts as an effective corrosion inhibitor for carbon steel in a hydrochloric acid medium. The inhibition process is attributed to the formatio...

  8. The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor.

    Minnoş, Bihter; Ilhan-Sungur, Esra; Çotuk, Ayşın; Güngör, Nihal Doğruöz; Cansever, Nurhan

    2013-01-01

    The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor was investigated over a 10-month period in a hotel. Planktonic and sessile numbers of sulphate reducing bacteria (SRB) and heterotrophic bacteria were monitored. The corrosion rate was determined by the weight loss method. The corrosion products were analyzed by energy dispersive X-ray spectroscopy and X-ray diffraction. A mineralized, heterogeneous biofilm was observed on the coupons. Although a biocide and a corrosion inhibitor were regularly added to the cooling water, the results showed that microorganisms, such as SRB in the mixed species biofilm, caused corrosion of galvanized steel. It was observed that Zn layers on the test coupons were completely depleted after 3 months. The Fe concentrations in the biofilm showed significant correlations with the weight loss and carbohydrate concentration (respectively, p < 0.01 and p < 0.01). PMID:23439037

  9. Corrosion of construction steel in pore simulated solution

    The corrosion of steel for reinforcing reinforced cement structures is a common problem particularly in structures that are exposed to a marine environment. Loosened masonry originating by the diametrical stress that iron oxides place on the cement is not unusual. These situations involve risk to people and goods and make it necessary to repair the structure to prolong its useful service life. Some preliminary results are presented from the reproduction of the corrosive process with the use of a solution that simulates the chemical surroundings in the concrete pores. These results will help to evaluate the incidence of contaminants (CO2, chloride ions), inhibitors and coatings, among others, in the following stages by conveniently adjusting the solution's composition. The composition of the chosen solution is: 0.01 mol NaOH - 0.002 mol/l Ca(OH)2. The effect was evaluated of a passive film generated on the surface of the steel of the reinforcements at 100 mV for 14 minutes and for 12 hours. This potential corresponds to the passive region, as determined by recording tests with cyclic volt amperometry and in accordance with the Pourbaix diagram for steel. The corrosion current was defined by recording the resistance to polarization using different electrochemical methods: potential sweep, potentiostatic jump and sweep electrochemical impedance. The results show that neither of the two times selected are enough to generate the metal's passive state and that the potential of 100 mV used to generate the passive film may be too low to produce a compact and long lasting layer, considering that the passive zone interval comes to 700 mV, according to the volt amperometry readings (CW)

  10. Corrosion of carbon steel in sodium methanoate solutions

    Barchiche, C.; Sabot, R.; Jeannin, M. [Laboratoire d' etude des materiaux en milieux agressifs (LEMMA), EA 3167, Univ. La Rochelle, Bat. Marie Curie, Avenue Michel Crepeau, F-17042 La Rochelle cedex 01 (France); Refait, Ph., E-mail: prefait@univ-lr.f [Laboratoire d' etude des materiaux en milieux agressifs (LEMMA), EA 3167, Univ. La Rochelle, Bat. Marie Curie, Avenue Michel Crepeau, F-17042 La Rochelle cedex 01 (France)

    2010-02-15

    The behaviour of steel electrodes in sodium methanoate solutions was studied by coupling electrochemical techniques (voltammetry, OCP vs. time) with in situ micro-Raman spectroscopy analyses of the corrosion products. The polarisation curves depended strongly on the methanoate concentration. For the smallest concentration (10{sup -3} mol L{sup -1}), the current density increased regularly with the applied potential. So the behaviour of the electrode was typical of an active material. In contrast, for the largest concentration (10{sup -1} mol L{sup -1}), the curves obtained were typical of a passive material. Methanoate ions favoured growth and stability of a passive oxide film more likely by adsorbing on its surface. The polarisation curve obtained for the intermediate concentration (10{sup -2} mol L{sup -1}) was unusual and testified of an imperfect passivation of the steel surface. Finally, steel electrodes were left at the open circuit potential in the methanoate solutions. In any case, the passivity was rapidly lost and a general corrosion of the surface took place. In situ Raman spectroscopy analyses at the early stage of the corrosion process demonstrated that the first product to form was a green rust, GR(HCOO{sup -}). It was oxidised later into gamma-FeOOH (lepidocrocite) by dissolved O{sub 2}. The process is then typical of what is usually observed in neutral or alkaline media, whatever the anions present and responsible of the GR formation. A new and detailed characterisation of GR(HCOO{sup -}) by X-ray diffraction was performed and a crystal structure is proposed.

  11. Detection of acoustic signal emitted during corrosion of 304 stainless steel

    In this work, corrosion of 304 stainless steel was evaluated by using acoustic emission(AE) technique. AE measurement system was set for detecting acoustic signal during accelerated corrosion test of the specimen. AE signal started to be detected after the time of pitting corrosion initiation was evaluated by anodic polarization curve. Pitting corrosion damage was confirmed by optical microscopic observation of the surface morphology. AE cumulative counts and amplitude according to corrosion time could be divided into three stages. These trends were discussed in relation with changing pitting corrosion mechanism. Feasibilities of AE technique for evaluation of corrosion damage and mechanism were suggested.

  12. Graphene grown on stainless steel as a high-performance and ecofriendly anti-corrosion coating for polymer electrolyte membrane fuel cell bipolar plates

    Pu, Nen-Wen; Shi, Gia-Nan; Liu, Yih-Ming; Sun, Xueliang; Chang, Jeng-Kuei; Sun, Chia-Liang; Ger, Ming-Der; Chen, Chun-Yu; Wang, Po-Chiang; Peng, You-Yu; Wu, Chia-Hung; Lawes, Stephen

    2015-05-01

    In this study, the growth of graphene by chemical vapor deposition (CVD) on SUS304 stainless steel and on a catalyzing Ni/SUS304 double-layered structure was investigated. The results indicated that a thin and multilayered graphene film can be continuously grown across the metal grain boundaries of the Ni/SUS304 stainless steel and significantly enhance its corrosion resistance. A 3.5 wt% saline polarization test demonstrated that the corrosion currents in graphene-covered SUS304 were improved fivefold relative to the corrosion currents in non-graphene-covered SUS304. In addition to enhancing the corrosion resistance of stainless steel, a graphene coating also ameliorates another shortcoming of stainless steel in a corrosive environment: the formation of a passive oxidation layer on the stainless steel surface that decreases conductivity. After a corrosion test, the graphene-covered stainless steel continued to exhibit not only an excellent low interfacial contact resistance (ICR) of 36 mΩ cm2 but also outstanding drainage characteristics. The above results suggest that an extremely thin, lightweight protective coating of graphene on stainless steel can act as the next-generation bipolar plates of fuel cells.

  13. Stress corrosion cracking susceptibility of stainless and duplex steels

    Costa, S.; Dias, C.; Pimenta, G. [Materials Laboratory, ISQ, Taguspark, Porto Salvo (Portugal); Costa, S.; Fonseca, I. [Centre for Molecular Sciences and Materials, FCUL, Lisboa (Portugal)

    2009-07-01

    Full text of publication follows: A comparative study of the influence of chloride concentration, temperature and metal crevice formation on SCC susceptibility of DIN 1.4404, 14410, 14410-CW, 1.4318 and 1.4462 steels has been performed. Single U-bend and double U-bend coupons were exposed to aqueous NaCl and MgCl{sub 2} solutions for 10 days, or until fracture, if sooner, at different temperatures. After exposure, samples were visually and dye penetrant inspected for crack or pitting determination. Results allowed producing corrosion maps accounting for the influence of [Cl{sup -}], T and crevice formation on the SCC susceptibility.

  14. Corrosion inhibition of carbon steel by extract of Buddleia perfoliata

    ROY LOPES-SESENES

    2012-06-01

    Full Text Available Buddleia perfoliata leaves extract has been investigated as a carbon steel corrosion inhibitor in 0.5 M sulfuric acid by using polarization curves, electrochemical impedance spectroscopy and weight-loss tests at different concentrations (0, 100, 200, 300, 400 and 500 ppm and temperatures, namely 25, 40 and 60 °C. Results showthat inhibition efficiency increases as the inhibitor concentration increases, decreases with temperature, and reaches a maximum value after 12 h of exposure, decreasing with a further increase in the exposure time. It was found that the inhibitory effect is due to the presence of tannines on this extract.

  15. Corrosion Inhibition of Carbon Steel in Chloride and Sulfate Solutions

    Amr Ahmed Elsayed

    2016-02-01

    Full Text Available Corrosion is a major problem in industry and in infrastructure; a huge sum of expenditure every year is spent on preventing, retarding, and repairing its damages. This work studies the engineering of an inhibitor for carbon steel metal used in the cooling systems containing high concentration of chloride and sulfate ions. For this purpose, the synergy between the dichromate, molybdate and nitrite inhibitors is examined and optimized to the best results. Moreover, care was taken that the proposed inhibitor is compliant with the environmental laws and regulations.

  16. General and Localized Corrosion of Borated Stainless Steels

    T.E. Lister; Ronald E. Mizia; A.W. Erickson; T.L. Trowbridge; B. S. Matteson

    2008-03-01

    The Transportation, Aging and Disposal (TAD) canister-based system is being proposed to transport and store spent nuclear fuel at the Monitored Geologic Repository (MGR) located at Yucca Mountain, Nevada. The preliminary design of this system identifies borated stainless steel as the neutron absorber material that will be used to fabricate fuel basket inserts for nuclear criticality control. This paper discusses corrosion test results for verifying the performance of this material manufactured to the requirements of ASTM A887, Grade A, under the expected repository conditions.

  17. Effect of microstructure variation on the corrosion behavior of high-strength low-alloy steel in 3.5wt% NaCl solution

    Guo, Yu-bing; Li, Chong; Liu, Yong-chang; Yu, Li-ming; Ma, Zong-qing; Liu, Chen-xi; Li, Hui-jun

    2015-06-01

    The effect of microstructure variation on the corrosion behavior of high-strength low-alloy (HSLA) steel was investigated. The protective property of the corrosion product layer was also explored. Experimental results reveal that the type of microstructure has significant effect on the corrosion resistance of HSLA steel. The measurement results of weight loss, potentiodynamic polarization curves, and electrochemical impedance spectroscopy indicate that the steel with acicular ferrite microstructure exhibits the lowest corrosion rate. Martensite exhibits a reduced corrosion resistance compared with polygonal ferrite. It is found that the surface of the acicular ferrite specimen uniformly covered by corrosion products is seemingly denser and more compact than those of the other two microstructures, and can provide some amount of protection to the steel; thus, the charge transfer resistance and modulus values of the acicular ferrite specimen are the largest. However, corrosion products on martensite and polygonal ferrite are generally loose, porous, and defective, and can provide minor protectiveness; thus, the charge transfer resistance values for polygonal ferrite and martensite are lower.

  18. Development of regional corrosion maps for galvanized steel by linking the RADM engineering model with an atmospheric corrosion model

    Spence, John W.; McHenry, John N.

    Annual corrosion rates for galvanized steel standard panels were estimated for eastern North America and part of southern Canada using the Regional Acid Deposition Model Engineering Model Model (ACM). The galvanized steel ACM examines the contributions of wet and dry deposition, including anthropogenic and naturally occurring atmospheric species to galvanized steel structure corrosion. The results show agreement between model-predicted and field-measured annual corrosion rates of galvanized steel panel except for an exposure site located in up-state New York. Further comparison of corrosion rates showed some spatial disagreement of the relative contributions to the individual corrosion processes, particularly for the New York site. In addition, RADM EM MM-4 was used to predict the change in ambient sulfur (S) concentrations and hydrogen ion deposition from a hypothetical uniform 50°, reduction in S emissions. Using the ACM, the effects of the emission reduction on the annually estimated corrosion rates were modeled. The results show a beneficial reduction in regional corrosion rates estimated annually. However, due to nonlinearities associated with wet and dry deposition, the corrosion rates decline in a less than 1:1 proportion to the emissions reduction.

  19. Corrosion of Steel in High-Strength Self-Compacting Concrete Exposed to Saline Environment

    Hana A. Yousif

    2014-01-01

    Full Text Available A research work was carried out to investigate the effectiveness of high-strength self-compacting concrete (SF-R in controlling corrosion of embedded steel. Reinforced concrete cylinders and plain cubes were subjected to 5% NaCl solution. Slump flow, J-ring, V-funnel, compressive strength, electrical resistance, and electrochemical tests were conducted. Corrosion resisting characteristics of steel were examined by monitoring corrosion potential, polarization resistance, corrosion currents, and Tafel plots. The relationship between corrosion current density and corrosion potential was established. Results were compared with characteristics of a grade 40 MPa reference concrete (R and grade 70 MPa conventional self-compacting concrete (SP. Results indicated that at 270 days of exposure, the corrosion currents for steel in SF-R were 63- and 16-fold lower compared to those of steel in R and SP concretes, respectively. This concrete showed a considerable increase in electrical resistance and compressive strength of 96 MPa at 28 days of exposure. Relying on corrosion risk classification based on corrosion current densities and corrosion potentials, the steel in SF-R concrete is definitely in the passive condition. The splendid durability performance of steel in SF-R concrete linked to adorable self-compacting features could furnish numerous opportunities for future structural applications in severe environmental conditions.

  20. Corrosion resistance of high-chromium steels in coal gasification atmospheres

    Kihara, S.; Nakagawa, K.; Ohtomo, A.; Kato, M.

    1987-06-01

    The corrosion resistances of AISI 347H and 310 stainless steels (SSs), 35Cr-45Ni steel, and chromized and aluminized AISI 347H SS were evaluated in simulated coal gasification atmospheres at 550, 600, and 650 C. The scales formed were mainly sulfides, with a small amount of oxides. Although the corrosion of AISI 347H and 310 SS increased with increasing temperature the corrosion of high-chromium steels, 35Cr-45Ni steel, and chromized AISI 347H SS remarkably decreased at 650 C. Weight gain decreased with increasing chromium content of steel. However, local corrosion occurred on 35Cr-45Ni steel at 600 C. The aluminized samples were the most corrosion resistant of the materials tested, but some cracks were found in the aluminized layer after 100-h exposure. Addition of HCI to the simulated gasification atmosphere generally accelerated corrosion by the formation of a porous outer scale. Pitting during downtime corrosion occurred only for AISI 347H SS exposed in the simulated gas involving 0.2 vol% HCI. The results of electrochemical measurements suggested that the downtime corrosion might by polythionic acid corrosion and crevice corrosion in the solution involving CI/sup -/.