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1

Corrosion and anti-corrosion protection of steel structures  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The thesis provides the basics about corrosion of steel structures. It describes different perspectives on genesis of corrosion – engineering, physics, chemistry and electrochemistry perspective, and what promotes its development. Next chapter is about anti-corrosion protection, actually it considers four methods of steel defense. The methods are: chatodic protection, electroplating or galvanization, because I am focused on steel structures, anti-corrosion paint coatings and protection with...

Kovac?ic?, Mateja

2012-01-01

2

Protection of Steel Constructions from Corrosive Destruction  

International Science & Technology Center (ISTC)

Development of the New Effective Sacrificial Anodes on the Basis of Secondary Aluminum for Protection of Steel Constructions of Hydropower Stations and Heat Stations of the Republic of Tajikistan from Corrosion Destruction

3

ANTI-CORROSION AND FIRE PROTECTION OF STEEL STRUCTURES  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The thesis discussed the problem of how to protect steel structures against corrosion and fire. Because of the scale selected topics we focused our work on the basics of the problem. First of all, we describe in section two of the thesis what corrosion is, how they arise and present types of corrosion. Also in this section we present the process of preparing the surface of steel structures, the selection of an appropriate protective coating as well as type of application method and finally th...

Ragolic?, Sandy

2012-01-01

4

Stainless steel structures and corrosion protection of steel structures according to Eurocode  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Steel is an excellent material to build with, but consideration must be given to the fact that unprotected steel corrodes, rusts, therefore, as a rule, the steel must be protected in some way. This can be done by reducing the tendency of the steel to corrode by using stainless steel or by treating the steel with a protection method. The two most common methods of protection are corrosion protection paint and zinc coating. To determine the method, the corrosive category must first be evaluated...

Karlsson, Niklas; O?jemyr, Jenny

2012-01-01

5

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

Energy Technology Data Exchange (ETDEWEB)

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.

Cook, Desmond C. [Department of Physics, Old Dominion University, Norfolk, VA 23529 (United States)]. E-mail: dcook@physics.odu.edu

2005-10-01

6

Corrosion protection of galvanized steels by silane-based treatments  

Science.gov (United States)

The possibility of using silane coupling agents as replacements for chromate treatments was investigated on galvanized steel substrates. In order to understand the influence of deposition parameters on silane film formation, pure zinc substrates were first used as a model for galvanized steel to study the interaction between silane coupling agents and zinc surfaces. The silane films formed on pure zinc substrates from aqueous solutions were characterized by ellipsometry, contact angle measurements, reflection absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and atomic force microscopy. The deposition parameters studied include solution concentration, solution dipping time and pH value of the applied solution. It appears that silane film formation involved a true equilibrium of hydrolysis and condensation reactions in aqueous solutions. It has been found that the silane film thickness obtained depends primarily on the solution concentration and is almost independent of the solution dipping time. The molecular orientation of applied silane films is determined by the pH value of applied silane solutions and the isoelectric point of metal substrates. The deposition window in terms of pH value for zinc substrates is between 6.0 and 9.0. The total surface energy of the silane-coated pure zinc substrates decreases with film aging time, the decrease rate, however, is determined by the nature of silane coupling agents. Selected silane coupling agents were applied as prepaint or passivation treatments onto galvanized steel substrates. The corrosion protection provided by these silane-based treatments were evaluated by salt spray test, cyclic corrosion test, electrochemical impedance spectroscopy, and stack test. The results showed that silane coupling agents can possibly be used to replace chromates for corrosion control of galvanized steel substrates. Silane coatings provided by these silane treatments serve mainly as physical barriers. Factors that affect the performance of a silane coupling agent in the application of corrosion control include chemical reactivity, hydrophobic character, siloxane crosslinker network, and film thickness. Good protections afforded by the silane treatments are a synergetic effect of all these factors.

Yuan, Wei

7

Microbial Iron Respiration Can Protect Steel from Corrosion  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2002-01-01

8

Galvanic Liquid Applied Coating System for Protection of Embedded Steel Surfaces from Corrosion  

Science.gov (United States)

The corrosion of reinforcing steel in concrete is an insidious problem for the Kennedy Space Center, government agencies, and the general public. Existing corrosion protection systems on the market are costly, complex, and time-consuming to install, require continuous maintenance and monitoring, and require specialized skills for installation. NASA's galvanic liquid-applied coating offers companies the ability to conveniently protect embedded steel rebar surfaces from corrosion. Liquid-applied inorganic galvanic coating contains one ore more of the following metallic particles: magnesium, zinc, or indium and may contain moisture attracting compounds that facilitate the protection process. The coating is applied to the outer surface of reinforced concrete so that electrical current is established between metallic particles and surfaces of embedded steel rebar; and electric (ionic) current is responsible for providing the necessary cathodic protection for embedded rebar surfaces.

Curran, Joseph; MacDowell, Louis; Voska, N. (Technical Monitor)

2002-01-01

9

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

10

The role of goethite in the formation of the protective corrosion layer on steels  

International Nuclear Information System (INIS)

The corrosion products formed on carbon and weathering steels exposed in marine, industrial and rural environments in the United States for 16 years have been investigated using Moessbauer spectroscopy, Raman spectrometry and chemical analysis. Moessbauer spectroscopy was used to measure the fraction of each oxide in the corrosion coatings and micro-Raman spectrometry was used to locate and map the oxides to 2 ?m spatial resolution. Moessbauer spectroscopy identified the corrosion products in the weathering steels as 75% goethite, 20% lepidocrocite and 5% maghemite. Raman analysis showed that the corrosion products generally formed as alternating layers containing different oxides. For the weathering steels the protective inner-layer closest to the steel substrate consisted of nano-sized goethite ranging in size from 5-30 nm and having a mean particle size of about 12 nm. The outer-layer close to the coating surface, consisted of lepidocrocite and goethite with the former oxide being most abundant. Electron probe micro-analysis measured significant chromium in the goethite close to the steel substrate. Comparison of the goethite in the corrosion products was made with synthetic chromium substituted goethite with nearly identical microstructural characteristics being recorded. It is concluded that chromium inclusions in the goethite are important for formation of a nano-phase oxide layer which may help protect the weathering steel from further corrosioneel from further corrosion

11

Methods for protection of high-strength welded stainless steel from corrosion cracking  

International Nuclear Information System (INIS)

The efficiency of protection from corrosion cracking under a bending stress of 100 kgf/mm2 in a salt mist and in a sulphur dioxide atmosphere, of welded joints of steel 08Kh15N5D2T with metallizing, galvanic and varnish coatings and lubricants, and of steel 1Kh15N4AM3 with sealing compounds has been investigated. Metallization of welded joints with aluminium and zinc efficiently increases corrosion resistance in a salt mist. Galvanic coatings of Cd, Zn, and Cr increase the time to cracking in a salt mist from 2-3 to 60-80 days. The protective properties of varnishes under the effect of a salt mist decrease in the following sequence: epoxy-polyamide enamel EP-140, acrylic enamel C-38, silicone enamels KO-834, KO-811, and KO-814. In an atmosphere containing SO2 0.15 vol.% at 100% relative humidity, the varnishes investigated, with the exception of the inhibited coating XC-596, show lower protective properties than in a salt mist. The high efficiency of protection from corrosion cracking in a salt mist of slots of steel 1Kh15N4AM3 when using organic sealing compounds U4-21 and U5-21, and also slushing lubricants and oils PVK, TsIATIM-201, K17, and AMS3 was established

12

The Effect of Oil on Carbon Dioxide Corrosion Inhibition on Carbon Steel - Potential for Improved Corrosion Protection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Foss, Martin Smedstad

2010-01-01

13

Evaluation of the protection behaviour of reinforcement steel against corrosion induced by chlorides in reinforced mortar specimens  

International Nuclear Information System (INIS)

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)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 drying for 5 days. The corrosion tests used in this investigation were gravimetric and electrochemical tests. The results showed satisfactory corrosion performance for all kinds of protection measures. However, the performance depended on the type of protection used. The best performance was obtained with tannin containing epoxy coated steel, followed by the steel treated by immersion in tannin containing solutions and finally by the addition of tannin (Black Wattle) or lignin to the mortar. All the protection measures evaluated in this study are economically viable and environmentally friendly and can therefore be considered for protecting reinforcement steels against corrosion. (author)

14

Aluminium electroplated from ionic liquids as protective coating against steel corrosion  

International Nuclear Information System (INIS)

The protective action of thin layers of aluminium electroplated on a carbon steel (UNI Fe360B) has been studied. The coatings were obtained via electroreduction, at room temperature, from an ionic liquid constituted by 1-butyl-3-methyl-imidazolium heptachloroaluminate. Coatings of different thickness, ranging from 10 to 40 ?m, were obtained. Their morphology and chemical composition were investigated using SEM microscopy coupled with EDX microanalysis and X-ray diffraction. Electrochemical tests (potentiodynamic polarization curves, open-circuit potential and electrochemical impedance spectroscopy) were performed in order to characterise the corrosion resistance of the coating in 3.5% NaCl aqueous solution. Visual investigation of the samples during long term of exposition to neutral salt spray gave an evaluation of their free corrosion properties. It was found that the aluminium layers deposited from ionic liquids significantly protect the substrate from the general corrosion and this action increases with the coating thickness

15

Process for the formation of an oxide layer to protect against corrosion on steel liable to corrosion  

International Nuclear Information System (INIS)

Steel liable to corrosion is treated with air at 2000C, and then with superheated steam at 4800C in a fluidised bed furnace (Re > 900) for some hours in order to remove organic impurities. Slow cooling in an air flow up to 1000C provides a closed, non-porous and firm oxide layer of the Spinell type. There is no hydrogen embrittlement, and the meachanical properties are retained in full. The rate of corrosion in a UF6 atmosphere is reduced 50 times compared to untreated steel. The thickness of the layer can be varied between 0.7 and 3 ?m by different durations of the treatment. Welded seams can be protected by this process without any loss of quality. (IHOE)

16

Interaction of Benzimidazoles and Benzotriazole: Its Corrosion Protection Properties on Mild Steel in Hydrochloric Acid  

Science.gov (United States)

Synergistic hydrogen-bonded interaction of alkyl benzimidazoles and 1,2,3-benzotrizole and its corrosion protection properties on mild steel in hydrochloric acid at different temperatures have been studied using polarization, EIS, adsorption, surface studies, and computational methods. The extent of synergistic interaction increases with temperature. Quantum chemical approach is used to calculate some electronic properties of the molecules and to ascertain the synergistic interaction, inhibitive effect, and molecular structures. The corrosion inhibition efficiencies and the global chemical reactivity relate to some parameters, such as total energy, E HOMO, E LUMO, and gap energy (? E). 1,2,3-Benzotrizole interacts with benzimidazoles derivatives up to a bond length of approximately 1.99 Å. This interaction represents the formation of a hydrogen bond between the 1,2,3-benzotrizole and benzimidazoles. This synergistic interaction of 1,2,3-benzotrizole and benzimidazole derivatives offers extended inhibition efficiency toward mild steel in hydrochloric acid.

Ramya, K.; Mohan, Revathi; Joseph, Abraham

2014-11-01

17

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

Directory of Open Access Journals (Sweden)

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.

Souza Maria Eliziane Pires de

2006-01-01

18

On the inhibitor protection of high-strength steels from corrosion cracking on the crack propagation stage  

International Nuclear Information System (INIS)

Possibilities of applying inhibitors to protect high-strength steels from corrosion crack growth in water medium, are studied. Mechanisms of their effect are investigated. Tests are carried out using the heat treated 45KhN2MFA steel (tempering 200 deg C) at the temperature of 25 deg C using beam samples (12x18x160 mm). It is shown that inhibitor protection of high-strength steels from corrosion cracking is a prospective way of increasing their corrosion crack resistance. Oxoanions are inhibitors of crack growth if they are reduced during adsorption, absorbing hydrogen ions. Inhibitors of the ICG type (inhibitors of crack growth) which suppress the process of hydrogen discharge - is a highly effective means of increasing corrosion crack resistance of high-strength alloys in the water medium. The effectiveness of inhibitors considered proves the hydrogen mechanism of water medium effect on crack growth in high-strength steels

19

POLYPHENYLENESULFIED/MONTOMORILLONITE CLAY NANOCOMPOSITE COATINGS: THEIR EFFICACY IN PROTECTING STEEL AGAINST CORROSION.  

Energy Technology Data Exchange (ETDEWEB)

Nanoscale montomorillonite (MMT) clay fillers became dispersed in a polyphenylenesulfied (PPS) matrix through the processes of octadecylamine (ODA) intercalation {yields} molten PPS co-intercalation {yields} exfoliation. Cooling this molten exfoliated material led to the formation of a PPS/MMT nanocomposite. The MMT nanofiller conferred three advanced properties on the semi-crystalline PPS: First, it raised its melting point by nearly 40 C to 290 C; second, it increased its crystallization energy, implying that an excellent adherence of the nanofillers surfaces to PPS in terms of a good interfacial bond; and, third, it abated the degree of its hydrothermal oxidation due to sulfide {yields} sulfite linkage transformations. When this advanced PPS nanocomposite was used as a corrosion-preventing coating for carbon steel in a simulated geothermal environment at 300 C, a coating of {approx}150 {micro}m thickness adequately protected the steel against hot brine-caused corrosion. In contrast, an MMT-free PPS coating of similar thickness was not nearly as effective in mitigating corrosion as was the nanocompsite; in fact, the uptake of corrosive ionic electrolyte by the unmodified coating increased with an extending exposure time.

SUGAMA, T.; GAWLIK, K.

2006-06-01

20

Interface-engineered parylene C coating for corrosion protection of cold-rolled steel  

Energy Technology Data Exchange (ETDEWEB)

Vacuum-deposited poly(chloro-p-xylylene), or parylene C, can be used for corrosion protection of cold-rolled steel (CRS) through interface engineering. Interface engineering replaces galvanizing, zinc phosphating, and cathodic electrocoating (E-coatings). Parylene C polymer has excellent bulk properties, including its moisture barrier, toughness, and electrical insulation characteristics, but its poor adhesion to most smooth or nonporous substrates has restricted its application. Parylene C coating applied directly to a CRS surface does not provide corrosion protection because there is no adhesion between the film and the substrate. It was shown that adhesion could be improved to the extent parylene-coated CRS panels performed as good as, if not better than, a control (E-coat/zinc phosphate/electrogalvanized steel [EGS]) under conditions of a commercial scab corrosion test. Improvement was achieved by placing an interlayer of plasma polymer to provide interfacial bonding to the CRS surface and the parylene C film. The interface engineering involved in-situ consecutive vacuum processes consisting of: the removal of oxides by (argon + hydrogen) plasma, the direct current (DC) cathodic plasma polymerization of trimethylsilane (TMS), the in-situ cathodic polymerization of methane on the plasma polymer of TMS (in the parylene reactor), and the deposition of parylene C.

Yasuda, H.; Chun, B.H.; Cho, D.L. [Univ. of Missouri, Columbia, MO (United States); Lin, T.J.; Yang, D.J.; Antonelli, J.A. [E.I. DuPont de Nemours and Co., Philadelphia, PA (United States)

1996-03-01

 
 
 
 
21

Polyindole top coat on TiO2 sol–gel films for corrosion protection of steel  

International Nuclear Information System (INIS)

Highlights: ? Polyindole top coating was electrochemically synthesized on TiO2 sol–gel coated stainless steel. ? The high protection was determined against corrosion; it was attributed to the adherent adsorption of the multilayer. ? Quantum calculations showed, there were a correlation experimental data and molecular parameters. - Abstract: The protection efficiency of polyindole film on stainless steel was enhanced via titanium dioxide pre-coating. The characterization of coatings was achieved by nuclear magnetic resonance and Fourier-transform infrared spectra. The surface morphology of electrodes was monitored with scanning electron microscope. The corrosion performance was investigated in 3.5% NaCl solution by electrochemical impedance spectroscopy and potentiodynamic measurements. The quantum calculations were employed, and theoretical parameters were determined. Results showed that the correlation between experimental and theoretical parameters. The high protection efficiency was observed against corrosion on the steel surface via forming a protective polyindole top coated titanium dioxide film.

22

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

Directory of Open Access Journals (Sweden)

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.

Jano, A.

2012-11-01

23

Influence of tantalum modifying addition on corrosion protective action of the diffusional chromized layers on carbon steel  

International Nuclear Information System (INIS)

The role of tantalum as of a modifying addition under 45 steel thermodiffusional saturation with chromium is investigated and a favourable effect of this element on the increase of protective properties of chromium-carbide coatings produced is demonstrated. A conclusion is made that the favourable effect of tantalum is conditioned by the production of carbide and other corrosion-resistant tantalum microphases in more deficient places of the coating in which an intense diffusional carbon supply from the protected steel is provided

24

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

Science.gov (United States)

Corrosion of metals is a serious and challenging problem faced worldwide by industry. Purified Leuconostoc mesenteroides exopolysaccharide (EPS) coatings, cast from aqueous solution, inhibited the corrosion of low-carbon steel as determined by electrochemical impedance spectroscopy (EIS). There were two different corrosion behaviors exhibited when EPS films from different strains were cast onto the steel. One EPS coating reacted immediately with the steel substrate to form an iron (III) oxide layer ("rust") during the drying process while another did not. The samples that did not flash corrode had higher corrosion inhibition and formed an iron (II) passivation layer during EIS testing that persisted after the cells were disassembled. Corrosion inhibition was strain-specific as polysaccharides with similar structure did not have the same corrosion potential. PMID:21290167

Finkenstadt, Victoria L; Côté, Gregory L; Willett, J L

2011-06-01

25

Thermodynamic aspects of the development of inhibitory methods of protecting steel from corrosion in salt water environments  

Directory of Open Access Journals (Sweden)

Full Text Available  The thermodynamics aspects of steel in water-salt solutions spontaneous corrosion and ways of purposeful creation of inhibition methods for its slow-down were considered. For the system Fe-H2O on the basis of diagram Pourbe analysis were determined definite ranges of potentials of metal and pH of the solutions for which corrosive destruction speed reduction were achieved. It is shown that the effective corrosion protection of steel can be achieved by means of measures which include application of inhibitors with simultaneous medium pH modification, as a result there takes place a transition of metal into a stable passivated state. Potentiostatic research of steel in water-salt solutions corrosion had confirmed efficiency of the method offered.

?.?. ??????????

2008-04-01

26

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

International Nuclear Information System (INIS)

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

27

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

Maria Eliziane Pires de, Souza; Edith, Ariza; Margarita, Ballester; Inez Valéria Pagotto, Yoshida; Luis Augusto, Rocha; Célia Marina de Alvarenga, Freire.

2006-03-01

28

Protection of steel from corrosion and hydrogen absorption by organic inhibitors: experimental and quantum-chemical studies  

Directory of Open Access Journals (Sweden)

Full Text Available The step-strip anodic dissolution technique was used to obtain concentration profiles of cathodic evolved H2 across the depth of Cr-Ni1810 steel under corrosion in water-salt media in the presence of SRB. The proposed approximation of the experimentally obtained distribution of hydrogen along the depth of steel by means of standard Gaussian function made it possible to establish the integral hydrogen content of the sub-layer (up to 80 ?m with high degree of accuracy. The efficiency of protective actions of the studied organic compounds against corrosion and hydrogen absorption by steel were compared with the data of quantum chemical computations performed for isolated molecules of the studied inhibitors with the help of the MNDO method. The results obtained point to a difference in the protective mechanisms of the studies inhibitors in case of anticorrosion action and hydrogen absorption by steel.

Beloglazov G.

2013-01-01

29

Synthesis, characterization and corrosion protection properties of poly(N-(acryloyloxymethyl) benzotriazole-co-glycidyl methacrylate) coatings on mild steel  

International Nuclear Information System (INIS)

The synthesis of copolymers from different feed ratios of N-(acryloyloxymethyl) benzotriazole (AMBT) and glycidyl methacrylate (GMA) was achieved by using free radical solution polymerization technique and characterised using FT-IR and 13C NMR spectroscopy. The thermal stability of the synthesized copolymers was studied using theremogravimetrtic analysis (TGA). The corrosion performances of mild steel specimens dip coated with different composition of copolymers were investigated in 0.1 M HCl by using potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) method. The polarization and impedance measurements showed different corrosion protection efficiency with change in composition of the copolymers. It was found that the corrosion protection properties are owing to the barrier effect of the polymer layer covered on the mild steel surfaces. However, it was observed that the copolymer obtained from 1:1 mole ratio of AMBT and GMA exhibited better protection efficiency than other combinations

30

Synthesis, characterization, and corrosion protection properties of poly(N-(methacryloyloxymethyl) benzotriazole-co-methyl methacrylate) on mild steel  

International Nuclear Information System (INIS)

The copolymers from different feed ratios of N-(methacryloyloxymethyl) benzotriazole (MMBT) and methyl methacrylate (MMA) has been synthesised using free radical solution polymerization technique and characterized using FT-IR and 13C NMR spectroscopy. The thermal stability of the polymers was studied using theremogravimetrtic analysis (TGA). The corrosion behaviors of mild steel specimens dip coated with different composition of copolymers have been evaluated by potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) method. These electrochemical properties were observed in 0.1 M HCl medium. The polarization and impedance measurements showed different corrosion protection efficiency with change in composition of the copolymers. It was found that the corrosion protection properties are owing to the barrier effect of the polymer layer covered on the mild steel surfaces. However, it was observed that the copolymer obtained from 1:1 mole ratio of MMBT and MMA exhibited better protection efficiency than other combinations

31

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

International Nuclear Information System (INIS)

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 thaBased 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 water and oil. Both the behavior of an oil droplet on an already water-wet surface and a water droplet on an already oil wet surface were investigated to determine the ability of the inhibitors to alter the affinity of the surface to water and oil respectively. The results indicated the no hydrophilic to hydrophobic transition occurred on bare steel and FeCO3 covered steel. The testing on surfaces with ferric corrosion products revealed that a water wet to oil-wet transition was possible on the ferric deposits using both PE and OI as inhibitor. The effect was, however, significantly stronger with OI than with PE. It was also found that the addition of the two inhibitors enhanced the hydrophobic behavior of an already oil-wet surface for both bare steel and steel with FeCO3 deposits. Water droplets entrained in the oil was in these experiments not able to spread on the steel surface. Electrophoresis measurements were used to determine influence of the three inhibitors on the zetapotential of FeCO3 and corroding iron particles. The tendency of the inhibitors to adsorb on surfaces with the same charge as the head group of the inhibitor was investigated. The focus in the testing on corroding iron was to determine the suitability of zetapotential as a method for investigating surface potential of corroding surfaces. It was found that the inhibitors adsorbed on iron carbonate regardless of the surface charge on the iron carbonate. On iron particles the experiments indicated that measurements of the surface potential of corroding particles could only be done when the corrosion rate had been reduced significantly using corrosion inhibitors. (Author)

32

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

Energy Technology Data Exchange (ETDEWEB)

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 they were exposed to water and oil. Both the behavior of an oil droplet on an already water-wet surface and a water droplet on an already oil wet surface were investigated to determine the ability of the inhibitors to alter the affinity of the surface to water and oil respectively. The results indicated the no hydrophilic to hydrophobic transition occurred on bare steel and FeCO{sub 3} covered steel. The testing on surfaces with ferric corrosion products revealed that a water wet to oil-wet transition was possible on the ferric deposits using both PE and OI as inhibitor. The effect was, however, significantly stronger with OI than with PE. It was also found that the addition of the two inhibitors enhanced the hydrophobic behavior of an already oil-wet surface for both bare steel and steel with FeCO{sub 3} deposits. Water droplets entrained in the oil was in these experiments not able to spread on the steel surface. Electrophoresis measurements were used to determine influence of the three inhibitors on the zetapotential of FeCO{sub 3} and corroding iron particles. The tendency of the inhibitors to adsorb on surfaces with the same charge as the head group of the inhibitor was investigated. The focus in the testing on corroding iron was to determine the suitability of zetapotential as a method for investigating surface potential of corroding surfaces. It was found that the inhibitors adsorbed on iron carbonate regardless of the surface charge on the iron carbonate. On iron particles the experiments indicated that measurements of the surface potential of corroding particles could only be done when the corrosion rate had been reduced significantly using corrosion inhibitors. (Author)

Foss, Martin Smedstad

2009-07-01

33

Corrosion protection by anaerobiosis.  

Science.gov (United States)

Biofilm-forming bacteria can protect mild (unalloyed) steel from corrosion. Mild steel coupons incubated with Rhodoccocus sp. strain C125 and Pseudomonas putida mt2 in an aerobic phosphate-buffered medium containing benzoate as carbon and energy source, underwent a surface reaction leading to the formation of a corrosion-inhibiting vivianite layer [Fe3(PO4)2]. Electrochemical potential (E) measurements allowed us to follow the buildup of the vivianite cover. The presence of sufficient metabolically active bacteria at the steel surface resulted in an E decrease to -510 mV, the potential of free iron, and a continuous release of ferrous iron. Part of the dissolved iron precipitated as vivianite in a compact layer of two to three microns in thickness. This layer prevented corrosion of mild steel for over two weeks, even in a highly corrosive medium. A concentration of 20 mM phosphate in the medium was found to be a prerequisite for the formation of the vivianite layer. PMID:11730124

Volkland, H P; Harms, H; Wanner; Zehnder, A J

2001-01-01

34

Study of electrodeposited polypyrrole coatings for the corrosion protection of stainless steel bipolar plates for the PEM fuel cell  

Energy Technology Data Exchange (ETDEWEB)

Polypyrrole coatings were prepared on stainless steel SS304 in order to study the corrosion protection provided by the conductive polymer in a simulated PEM fuel cell environment. The polypyrrole was deposited by electrochemical polymerization with 0.04, 0.07 and 0.14gcm{sup -2} onto SS304 electrodes. Polarization curves, taken after immersion for 1, 3 or 24h in 0.1M sulphuric acid at either room temperature or 60{sup o}C were used as an accelerated test. For short immersion times, it was found that corrosion current densities (at free corrosion potentials), diminished up to 2 orders of magnitude for samples tested at room temperature and up to 4 orders of magnitude for samples tested at 60{sup o}C. Furthermore, at potentials in the range of the PEM fuel cell anode potential, corrosion rates also decreased up to several orders of magnitude. However, these protective properties were lost at longer times of immersion. The addition of DBSA to the polypyrrole coatings did lead to improved corrosion current densities at the free corrosion potential, however due to the loss of passivity of these samples, the corrosion rates in the potential range applicable to PEM fuel cells were either similar to or larger than bare metal. SEM was used to determine the morphology of the coatings and showed that the most homogeneous coating was obtained for 0.07gcm{sup -2} polypyrrole, without the incorporation of DBSA. (author)

Garcia, M.A. Lucio [CIE-UNAM, Priv. Xochicalco S/N, 62580 Temixco, Morelos (Mexico); Smit, Mascha A. [Unidad de Materiales, Centro de Investigacion Cientifica de Yucatan (CICY), Calle 43 no. 130, col. Chuburna de Hidalgo, 97200 Merida, Yucatan (Mexico)

2006-07-14

35

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

International Nuclear Information System (INIS)

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.

36

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

Energy Technology Data Exchange (ETDEWEB)

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: {yields} Ordered mesoporous composite film was deposited on the 304 stainless steel. {yields} This composite film exhibited excellent protective performance in 0.5 M H{sub 2}SO{sub 4}. {yields} The film exhibited a high surface tension with water contact angle close to 90{sup o}. - 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, N{sub 2} adsorption-desorption and TEM, the composite films exhibit ordered mesoporous structures. The corrosion tests in 0.5 M H{sub 2}SO{sub 4} 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.

Wang Tao [College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); He Jianping, E-mail: jianph@nuaa.edu.c [College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Sun Dun; Zhou Jianhua; Guo Yunxia; Ding Xiaochun; Wu Shichao; Zhao Jianqing; Tang Jing [College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

2011-04-15

37

Corrosion of steel in concrete  

International Nuclear Information System (INIS)

A comparative study has been made of those properties of Massiv and Standard cements which are considered to determine their ability to protect steel reinforcement from corroding. Saturated Massiv cement has a higher evaporabel water content, but a significantly finer pore structure than has saturated Standard cement. This fine structure resulted in an electrical resistivity ten times higher and chloride diffusivity ten times lower than those of Standard cement. Electrochemical measurements have shown that the passive current density of steel in Massiv mortar is higher than that of steel in Standard mortar, but the higher current should lead to a more rapid decrease in potential to a level at which neither chloride attack of hydrogen evolution will occur. Whereas steel in Standard mortar was found to be highly susceptible to crevice corrosion, no such attack has been observed in Massiv mortar. Moreover, the initiation of chloride induced corrosion and the subsequent rates of corrosion were both lower in Massiv mortar than in Standard mortar. Thus, it may be predicted that Massiv cement would provide greater protection for steel reinforcement in underground structures exposed to chloride containing ground water than would Standard cement. (author)

38

Corrosion resistant steel  

International Nuclear Information System (INIS)

Corrosion-resistant chromium-nickel steel containing cerium and vanadium additions is developed. It is aimed at producing welding structures operating at cryogenic temperatures. The above steel also contains C, Mo, Co, Ca, Y, Fe. Ce and V additions permit to increase the impact strength of joints at the temperature of -253 deg and resistance to the formation of welded cracks by way of grain size refinement of the initial coarse-grained structure and decreasing steel tendency to grain growth during welding heatings. A considerable economic effect from the introduction of the suggested steel is supposed

39

Nanocomposite films for corrosion protection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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?C...

Sababi, Majid

2013-01-01

40

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

Directory of Open Access Journals (Sweden)

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.

Ayman M. Atta

2014-07-01

 
 
 
 
41

Preparation of crosslinked amphiphilic silver nanogel as thin film corrosion protective layer for steel.  

Science.gov (United States)

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. PMID:25036152

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

2014-01-01

42

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

Science.gov (United States)

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.

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

2012-04-01

43

Migrating corrosion inhibitor protection of concrete  

Energy Technology Data Exchange (ETDEWEB)

Migrating corrosion inhibitors (MCI) were developed to protect steel rebar from corrosion in concrete. They were designed to be incorporated as an admixture during concrete batching or used for surface impregnation of existing concrete structures. Two investigations are summarized. One studied the effectiveness of MCIs as a corrosion inhibitor for steel rebar when used as an admixture in fresh concrete mix. The other is a long-term study of MCI concrete impregnation that chronicles corrosion rates of rebar in concrete specimens. Based on data from each study, it was concluded that migrating corrosion inhibitors are compatible with concrete and effectively delay the onset of corrosion.

Bjegovic, D.; Miksic, B.

1999-11-01

44

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

Science.gov (United States)

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.

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

2002-01-01

45

Corrosion protection of 316 L stainless steel by a TiO2 nanoparticle coating prepared by sol-gel method  

International Nuclear Information System (INIS)

A uniform and TiO2 nanoparticle coating on steels has been prepared using sol-gel method and hydrothermal post-treatments. The morphology and structure of the coatings were analysed using atomic force microscopy and X-ray diffraction. The anticorrosion performances of the coatings in dark and under ultraviolet illumination have been evaluated by using electrochemical techniques. The influences of coating thickness, pH and NaCl concentration on corrosion protection have been examined as well. The results indicate that the TiO2 nanoparticle coatings on steels exhibit an excellent corrosion resistance due to a ceramic protective barrier on metal surface in dark, and a photo-generated cathodic protection current under UV illumination. The electrochemical impedance spectroscopy measurements provide an explanation to the increased resistance of nano TiO2 particles coated 316 L stainless steel against corrosion

46

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

International Nuclear Information System (INIS)

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(PO4)6(OH)2. 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.

47

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

Directory of Open Access Journals (Sweden)

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.

Florica Simescu and Hassane Idrissi

2008-01-01

48

Adsorption rate and protective effect of tributyl(cyclohexyl)ammonium chloride inhibitor on the acidic corrosion of steel  

Energy Technology Data Exchange (ETDEWEB)

The inhibition of corrosion of a steel surface by an inhibitor, tributyl(cyclohexyl)ammonium chloride (TBCA), was investigated by gravimetric and electrochemical polarization measurements in various aqueous solutions of HCl and H{sub 2}SO{sub 4} acids. It is known that the most extensive corrosive destruction proceeds during the initial stage of contact between the metallic surface and the aggressive surroundings. The change from H{sub 2}SO{sub 4} to HCl considerably decreases the time for formation of an adsorption layer. The high adsorption of the surface-active cationic TBCA on the steel electrode surface can be explained by the specific adsorption of Cl{sup -} anions increasing the negative charge on the electrode surface. It was observed that the value of the polarizing current can be increased from time to time by addition of more TBCA inhibitor. This fact can be explained by the low stability of the film-forming layer on the steel. A similar decrease of the protective effect was also observed in HCl solution. The inhibitor provides at least a slowing of the corrosion process ({tau}=21 min). It was found that an increase in H{sub 2}SO{sub 4} concentration from 1.0 to 0.2 N did not change the protective action of the inhibitor and had rather high values ({theta}=283 ma/h, {psi}=84%, and {tau}=14 min at [I]=3.5 x 10{sup -4} mol/L). It was shown that the attraction constant has a negative value (A=-1.5 and K{sub a}=22.3) for the inhibitor, which relates to a high value for the adsorption ability of TBCA in HCl solution and therefore with the intermolecular repulsive force between adsorption molecules having similar charges. The protective action of TBCA increases with an increase in temperature, which is correlated with the chemical nature of its adsorption on the steel surface. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Magerramov, A.M.; Aliyev, I.A.; Khalilova, F.I. [Faculty of Chemistry, Baku State University (Azerbaijan); Rzayev, Z.M.O. [Chemical Engineering Department, Faculty of Engineering, Hacettepe University, Beytepe, Ankara (Turkey)

2010-08-15

49

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

Directory of Open Access Journals (Sweden)

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.

Jenko, M.

2008-04-01

50

Modernization of technology - corrosion protection - environmental protection  

Energy Technology Data Exchange (ETDEWEB)

Discusses corrosive properties of the atmosphere in Upper Silesian coal mines and corrosion rate of equipment used in the mines. Types of corrosion protection used by the Mining Electronics Plant in Tychy manufacturing control equipment, computerized control equipment and measuring instruments for underground mines are comparatively evaluated. The following types of corrosion protection are used: paints (organic and inorganic), metal surface coatings (zinc, aluminium), electroplated coatings, surface coatings made of plastics. Manufacturing technologies of corrosion protection, properties of materials, effects of corrosion protection on corrosion rate of metals, specific problems associated with corrosion protection of electronic equipment, and methods for quality control of corrosion protection are discussed. 5 refs.

Borkowska, D.; Banas, J.; Kuryatto, I. (Zaklad Elektroniki Gorniczej, Tychy (Poland))

1989-12-01

51

Ormocer (ZrO2-PMMA) films for stainless steel corrosion protection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The chemical protection of 316 L stainless steel coated with ORMOCER coatings of polymethylmethacrylate (PMMA) and ZrO2 has been verified. The coatings were dip-coated on the substrates from sols prepared by mixing zirconium propoxide (ZrOC3H7)4, isopropanol (C3H7OH), glacial acetic acid (CH3COOH), polymethylmethacrylate and water under application of ultrasounds. The films were heat treated between 40 and 300°C in air up to 20 h. Their morphology was studied by electron scanning microscopy ...

Luna, Fernando P.; Atik, Mohamed; Messaddeq, Sandra H.; Aegerter, Michel A.

1997-01-01

52

Poly(N-ethylaniline) coatings on 304 stainless steel for corrosion protection in aqueous HCl and NaCl solutions  

International Nuclear Information System (INIS)

Poly(N-ethylaniline) (PNEA) coatings were grown by potentiodynamic synthesis technique on 304 stainless steel (SS) alloy from 0.1 M of N-ethylaniline (NEA) in 0.3 M oxalic acid solution. Characterization of adhesive and electroactive PNEA coatings was carried out by cyclic voltammetry, FT-IR spectroscopy and scanning electron microscopy (SEM) techniques. The protective properties of PNEA coatings on SS were elucidated using linear anodic potentiodynamic polarization, Tafel and electrochemical impedance spectroscopy (EIS) test techniques, in highly aggressive 0.5 M HCl and 0.5 M NaCl solutions. Linear anodic potentiodynamic polarization test results proved that PNEA coating improved the degree of protection against pitting corrosion in HCl and NaCl solutions. Tafel test results showed that PNEA coating appears to enhancement protection for SS in 0.5 M NaCl and 0.5 M HCl solutions. However, according to long-term EIS results, PNEA coating is better for the protection of SS electrodes during the long immersion period in NaCl compared to that in HCl medium

53

Steel corrosion protection by means of alkyd paints pigmented with calcium acid phosphate  

Energy Technology Data Exchange (ETDEWEB)

The use of classic anticorrosive pigments is becoming more and more restricted by increasing environmental concerns; they are gradually being replaced by zinc phosphate and related compounds. Other anticorrosive pigments such as surface-exchanged silicas were also proposed. The object of this research is to study the anticorrosive properties of calcium acid phosphate as an inhibitive pigment, introducing a careful selection of complementary pigments in order to achieve an efficient anticorrosive protection. Several alkyd paints were prepared and evaluated through accelerated and electrochemical tests. The nature of the passive film formed was also studied. Paint containing zinc oxide and calcium carbonate (50/50) as complementary pigments showed the best performance in the salt spray test. Zinc oxide and calcium carbonate decreased film permeability and improved steel passivation. The passive film was composed of ferric oxyhydroxide, the pores of which became plugged by ferric phosphate.

Amo, B. del; Romagnoli, R.; Vetere, V.F. [CIC-CONICET, La Plata (Argentina)

1999-06-01

54

Boroaluminide coatings on steels for protection against high temperature corrosion and erosion  

Energy Technology Data Exchange (ETDEWEB)

Low alloy Cr-Mo containing ferritic-martensitic steels have been widely used in power plant applications. Despite their very good high temperature mechanical properties they are nevertheless prone to high temperature oxidation and erosion when they are used in steam containing environments. Appropriate protective coatings can be applied to these alloys in order to improve their oxidation and wear properties, while preserving the mechanical properties of the base materials. The coating system chosen in this work is boroaluminide as the recently investigated characteristics of this coating hold promise for such an application. The coating was deposited by pack cementation and characterized, in terms of morphology and phase identification, by means of optical and scanning electron microscopy, and X-Ray diffractometry respectively. Some physical and mechanical properties, relevant to the intended application, such as steam oxidation resistance, and fatigue strength determined by ball-indenter-impact-testing for both, coating and substrate, are reported. (orig.)

Omar, H.; Michalidis, N. [Aristotle Univ., Thessaloniki (Greece). Dept. of Mechanical Engineering; Tsipas, S.A. [Univ. Carlos III of Madrid, Leganes (Spain). Dept. of Materials Science; Papamichael, G.; Lefakis, H. [Western Macedonia Univ., Kozani (Greece). Dept. of Mechanical Engineering

2010-07-01

55

40 CFR 280.31 - Operation and maintenance of corrosion protection.  

Science.gov (United States)

...false Operation and maintenance of corrosion protection. 280.31 Section...31 Operation and maintenance of corrosion protection. All owners and operators of steel UST systems with corrosion protection must comply with the...

2010-07-01

56

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 tec...

Bamoulid, L.; Maurette, M. -t; Caro, D.; Guenbour, A.; Ben Bachir, A.; Aries, L.; El Hajjaji, S.; Benoit-marquie?, F.; Ansart, Florence

2008-01-01

57

Preparation, characterisation and corrosion behaviour of protective coatings on stainless steel samples deposited by plasma detonation techniques  

International Nuclear Information System (INIS)

Plasma-detonation techniques have been used to modify the surface of austenitic stainless steel samples in order to improve their corrosion resistance. Deposition of Al2O3 coatings in combination with high current electron beam treatment and deposition of titanium nitride (TIN) were applied for this purpose. The characterisation of the samples was performed using nuclear reaction analysis and Rutherford backscattering spectroscopy. The corrosion behaviour of the samples was investigated in H2SO4 using electrochemical techniques (cyclo-voltammetry and potentiodynamic polarisation). The values of the critical and passivation current density as well as of the corrosion, passivation and re-passivation potentials, showed a considerable increase of the corrosion resistance of the coated steel samples. This improvement is connected with the properties of the modified region (thickness, adhesion). The surface morphology and microstructure of the specimens before and after the corrosion experiments were investigated by X-ray diffraction, scanning and transmission electron microscopy

58

Effective corrosion protection  

International Nuclear Information System (INIS)

The following methods have been developed to minimize corrosion in conventional and nuclear power plants, heating station equipment, and other heat generating installations and district heat distribution grids: (1) chemical cleaning of steam and water boilers by using a special active agent which forms compounds with multivalent metal ions and dissolves already existing deposits on the wall, (2) corrosion protection of steam and hot water boilers of all systems and types during shut down by the use of a film-forming substance, and (3) corrosion protection of warm and hot water grids during operation or shut down by introducing a corrosion inhibitor which forms a protective film on all metal surfaces upon which the warm or hot water impinges during routine operation. The technical and economical advantages of the methods are summarized

59

Corrosion of steel in concrete  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The research work that is presented in this thesis aims at mapping out the various mechanisms which control the process of steel corrosion in concrete. The process of corrosion is illustrated with a schematic model where the service life is divided into a period of initiation and a period of propagation. The time up to the initiation of the corrosion process is determined by the flow of penetrating substances into the concrete cover and by the threshold concentration for corrosion to start. T...

Tuutti, Kyo?sti

1982-01-01

60

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

International Nuclear Information System (INIS)

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.on protection.

 
 
 
 
61

Corrosion resistance of trip steels  

International Nuclear Information System (INIS)

Anodic polarization tests on certain metastable austenitic (TRIP) steels having very high strength and good ductility, with contents of sulfur, phosphorus, and other impurities comparable to those of commercial alloy steels, indicate they would have about the same general corrosion resistance as commercial Type 316 stainless steel and appreciably better resistance to pitting in sea water. Cold-working of a TRIP steel increased its resistance to pitting somewhat and decreased its indicated general corrosion resistance slightly; these effects appear to be due to the transformation of austenite to martensite as a result of the cold-working rather than to the cold-working itself. (U.S.)

62

Corrosion protection by electro-deposited aluminum  

Science.gov (United States)

Deposition of aluminum on various substrates by using a nonaqueous organic electrolytic system is described. The metallic deposit has a high purity and good corrosion protection properties. It can be used as a substitute for the highly toxic cadmium. Possible fields of application are protection against corrosion of high strength steels without any danger of hydrogen embrittlement, the coating of lightweight materials like aluminum, magnesium, and titanium alloys, and the fabrication of fiber reinforced metal matrix composites.

Suchentrunk, R.

1980-03-01

63

Some peculiarities of corrosion of wheel steel  

Directory of Open Access Journals (Sweden)

Full Text Available 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 corrosion nucleation and their influence on corrosion depends on type of inclusion. Mechanism of corrosion of wheel steel corrosion was discussed.

Alexander SHRAMKO

2009-01-01

64

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  

Energy Technology Data Exchange (ETDEWEB)

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 drying for 5 days. The corrosion tests used in this investigation were gravimetric and electrochemical tests. The results showed satisfactory corrosion performance for all kinds of protection measures. However, the performance depended on the type of protection used. The best performance was obtained with tannin containing epoxy coated steel, followed by the steel treated by immersion in tannin containing solutions and finally by the addition of tannin (Black Wattle) or lignin to the mortar. All the protection measures evaluated in this study are economically viable and environmentally friendly and can therefore be considered for protecting reinforcement steels against corrosion. (author)

Crivelaro, Marcos

2002-07-01

65

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

International Nuclear Information System (INIS)

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

66

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

67

Corrosion fatigue of steel in concrete structures  

International Nuclear Information System (INIS)

The basic objective of this research programme was to clarify to what extent the traditional alkaline protection is sufficient also under cyclic actions in chloride environments or under which conditions more protection efforts (coating, cathodic protection) would be required. As a measure of the efficiency of the protection the fatigue strength of the prestressing steel under simultaneous action of different corrosive environments has been investigated. Corrosion fatigue tests on 3 series of 3-point-loaded beams post-tensioned with a 7-wire monostrand tendon according to German standard specifications have been performed. The corrosive environment was produced for the beams of the first two series by wetting their surface with salt water in regular intervals. For the third series of beams chloride has been added to the concrete and the grouting mortar and the beams have been wetted with water at proper intervals. Constant amplitude load cycles have been applied. (orig./MM)

68

Improvement of superficial protection of steel concrete supports of the contact network against corrosion  

Directory of Open Access Journals (Sweden)

Full Text Available The influence of different water-repellent rendering compounds for steel concrete supports of a contact network on change of their electric resistance and water absorption is under study. It is shown that the domestic production "Silol" has the best parameters on these indices.

V.G. Sychenko

2012-08-01

69

Protection of Mild Steel Against Sulphides Corrosion In Petroleum Oil Industry  

International Nuclear Information System (INIS)

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

70

Marine corrosion of mild steel at Lumut, Perak  

Science.gov (United States)

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.

Ting, Ong Shiou; Potty, Narayanan Sambu; Liew, Mohd. Shahir

2012-09-01

71

Inhibitor protection of steel from corrosion and hydrogen impregnation, and the technology of chemical cleaning of equipment in solutions of sulfuric and sulfamic acids  

Energy Technology Data Exchange (ETDEWEB)

An analysis is made and the results are presented of investigations of the features of inhibitor protection of steel from corrosion and hydrogen impregnation and also of cleaning of industrial equipment in solutions of sulfuric and sulfamic acids. Acid cleaning of equipment (thermal power, chemical, petroleum refining, and petro-chemical industries, etc.) with hydrochloric acid is the most widely used. The data of plant investigations indicate the high protective effectiveness of inhibited sulfamic acid solutions; the best is an acid solution with additions of KhOSP-10 inhibitor. The sulfamic acid without inhibitor additions does not fulfill the requirements imposed for removal of scale and prevention of copper deposits.

Mindyuk, A.K.; Kost, Y.S.; Savitskaya, O.P.; Sholok, V.I.; Tkach, A.D.

1986-01-01

72

Development of low-temperature galvanizing and its application for corrosion protection of high-strength steels; Entwicklung einer niedrigschmelzenden Legierung und deren Applikation zum Korrosionsschutz hochfester Staehle  

Energy Technology Data Exchange (ETDEWEB)

Apart from reliability and quality, vehicle safety and cost efficiency are the decisive criteria for automobile manufacturers. Corrosion protection plays a decisive role because it increases the service life. The ultra-high-strength steels are materials which exhibit high lightweight potential as well as a very good energy absorption capacity because of their mechanical properties. In connection with the possibility of hot forming, they are predestined for the fabrication of complicated, load-compatible shapes in the crash-relevant frame and body construction. The application of these steel qualities has been carried out in structural parts which are protected from corrosion by a hot-dip coat of FeAl7 - the so-called Usibor. However, at the moment there is no ready-for-production solution for later corrosion protection of already hot-formed parts. Therefore, a corrosion protection system on the basis of conventional low-temperature galvanizing processes has been developed and utilized. First, the softening behavior of the highly-resistant 22MnB5 substrate was analyzed. Afterwards, a galvanizing system was developed and applied. The corrosion protection coatings were characterized with regard to their structure and corrosion protection potential. As a result, a significant improvement of the corrosion behaviour has occurred. (Abstract Copyright [2008], Wiley Periodicals, Inc.) [German] Neben Zuverlaessigkeit und Qualitaet sind vor allem Fahrzeugsicherheit und Wirtschaftlichkeit entscheidende Kriterien fuer den Automobilhersteller. Der Korrosionsschutz spielt dabei eine herausragende Rolle, da hierdurch die Lebens- und Gebrauchsdauer erhoeht wird. Mit der Bereitstellung hoechstfester Stahlqualitaeten stehen Werkstoffe zur Verfuegung, die auf Grund ihrer mechanischen Eigenschaften ein hohes Leichtbaupotenzial sowie ein sehr gutes Energieabsorptionsvermoegen aufweisen. In Verbindung mit der Moeglichkeit der Warmformgebung sind sie damit praedestiniert fuer die Herstellung komplizierter, beanspruchungsgerechter Formen im crashrelevanten Karosseriebereich. Der Einsatz dieser Stahlqualitaeten erfolgt bislang in Strukturbauteilen, die mit einem Schmelztauchueberzug aus FeAl7, sog. Usibor, vor Korrosion geschuetzt sind. Jedoch besteht zurzeit keine serienreife Loesung fuer den nachtraeglichen Korrosionsschutz von bereits warmumgeformten Bauteilen. Deshalb wurde ein Korrosionsschutzsystem auf Basis des herkoemmlichen Schmelztauchverzinkungsprozesses entwickelt und appliziert. Zunaechst wurde das Entfestigungsverhalten des hoechstfesten Substrats 22MnB5 analysiert. Anschliessend wurde ein Legierungssystem entwickelt und appliziert. Die so entstandenen Korrosionsschutzschichten wurden hinsichtlich ihrer Struktur und des Korrosionsschutzpotenzials charakterisiert. Im Ergebnis tritt eine deutliche Verbesserung des Korrosionsverhaltens ein. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Wielage, B.; Lampke, T.; Steinhaeuser, S. [Technische Universitaet Chemnitz (Germany). Institut fuer Werkstoffwissenschaft und Werkstofftechnik; Strobel, C. [Fachhochschule Ingolstadt (Germany); Merklinger, V.

2008-12-15

73

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

International Nuclear Information System (INIS)

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 investi120 and 600 grit size were used to investigate the effect of surface roughness on the corrosion inhibition efficiency.

74

Sol-gel deposition of ZrO2 films in air and in oxygen-free atmospheres for chemical protection of 304 stainless steel : a comparative corrosion study  

Digital Repository Infrastructure Vision for European Research (DRIVER)

ZrO2 coatings for corrosion protection were deposited on 304 stainless steel by sol-gel method using zirconium propoxide as precursor and densified in air and in oxygen-free (argon or nitrogen) atmospheres. XRD and IR data of the films were practically independent of the atmosphere used in the densification step showing that the ceramic oxide is properly formed from the precursor. The corrosion behavior of the stainless steel substrate was studied by potentiodynamic polarization curves in the...

Aegerter, Michel A.; Lima-neto, P.; Perdomo, L. F.; Avaca, Luis A.

1999-01-01

75

Steel corrosion in radioactive waste storage tanks  

International Nuclear Information System (INIS)

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)

76

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

Science.gov (United States)

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.

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

2006-11-01

77

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

International Nuclear Information System (INIS)

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

78

Tests Of Protective Coats For Carbon Steel  

Science.gov (United States)

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.

Macdowell, Louis G., III

1995-01-01

79

BWR steel containment corrosion  

Energy Technology Data Exchange (ETDEWEB)

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.

Tan, C.P.; Bagchi, G.

1996-04-01

80

BWR steel containment corrosion  

International Nuclear Information System (INIS)

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

 
 
 
 
81

Characterization of SiO2-TiO2 Hybrid Corrosion Protective Coatings on Mild Steel  

Science.gov (United States)

Organic-inorganic SiO2-TiO2 sol-gel coatings were prepared and applied on a mild steel substrate using dip coating technique and subsequently heat treated at 200 and 300 °C to improve the corrosion resistance. The coating sols were synthesized using Glycidoxytrimethoxysilane and titanium tetraisopropoxide as precursor materials. The corrosion resistances of the both coated and uncoated samples were evaluated by the Tafel polarization and electrochemical impedance spectroscopy in NaCl solution. The microstructure of coated specimens was characterized by scanning electron microscopy. Fourier transformed infrared and energy dispersive spectroscopy analyses were used to identify the presence of various functional groups in the coating solutions. A comparison of the corrosion resistance of the coated and uncoated mild steel was presented. i corr values of coated specimens heat treated at 200 °C were between 6.9 and 9.2 times smaller than those of uncoated specimen. In the case of coated specimens heat treated at 300 °C, i corr values were 4.4 and 5 times smaller than those of uncoated specimen. The coating film was noted to be smooth and between 7.2- and 7.5-µm thick. The measured electrochemical parameters indicated that the corrosion resistance was improved by the coating film. The elasticity of the coating can be improved by the presence of organic groups in the coating which reduces stress and crack formations during sintering. Ultimately, crack-free and elastic coating was obtained by heat treating of organic-inorganic coating at as low as 200 °C.

Kirtay, Sebahattin

2014-09-01

82

Evaluation and control of environmental corrosion for aluminum and steel alloys  

Science.gov (United States)

Corrosion protection systems for aerospace application and the effects of surface treatments and methods of controlling stress corrosion are evaluated. Chromate pigmented systems were found to be most effective for aluminum alloys; zinc-rich coatings gave the greatest protection to steel alloys. Various steel and aluminum alloys are rated for stress corrosion resistance.

Franklin, D. B.

1977-01-01

83

Corrosion of carbon steel welds  

International Nuclear Information System (INIS)

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)

84

EXPERIMENTAL STUDY ON EFFECTS OF CATHODIC PROTECTION TO PREVENT MACRO-CELL CORROSION OF STEEL IN CONCRETE  

Science.gov (United States)

Reinforcing bars embedded in concrete tend to corrode due to salt attack under marine environments. Corrosion of bars might be often caused with phenomenon of macro-cell. Cathodic protection has been, so far, applied to control the corrosion of reinforcing bars in RC members. In order to make clear the mechanisms of macro-cell corr osion and the effect of cathodic protecti on, laboratory tests were carried out. Testing concrete specimens contained two reinforcing bars which were buried at upper area of specimens and at lower area of ones, respectively. Lower zone of the concrete specimens were immersed in water. Testing results indicated as follows: (1) reinforci ng bars under wetting condition were anode and reinforcing bars under drying one cathode, (2) current density of macro-cell between two bars increased according as the potential difference increased and electric resistance of the concrete between two bars decreased, and (3) cathodic protection was effective to prevented macro-cell corrosion of reinforcing bars in concrete. Furthermore, it was presumed that corroded iron might be reduced to metal iron due to the protection current.

Yamamoto, Satoru; Ueno, Moe; Ishii, Kouji; Seki, Hiroshi

85

Synthesis and application of hybrid polymer composites based on silver nanoparticles as corrosion protection for line pipe steel.  

Science.gov (United States)

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. PMID:24840897

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

2014-01-01

86

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

Directory of Open Access Journals (Sweden)

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.

Ayman M. Atta

2014-05-01

87

Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel  

DEFF Research Database (Denmark)

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 corrosion rates, when biofilm and corrosion products cover the steel surface. However, EIS might be used for detection ofMIC. EN is a suitable technique to characterise the type of corrosion attack, but is unsuitable for corrosion rate estimation. The concentric electrodes galvanic probe arrangement initiates localised corrosion on the anode and seems applicable to evaluate the risk of MIC. Hydrogen permeation measurements are very useful to monitor hydrogen induced cracking accelerated by MIC.

Hilbert, Lisbeth Rischel

2000-01-01

88

Evaluation of Multiple Corrosion Protection Systems for Reinforced Concrete Bridge Decks.  

Science.gov (United States)

The performance of corrosion protection systems for reinforcing steel in concrete is evaluated. In addition to conventional and conventional epoxy-coated reinforcement, the corrosion protection systems tested include epoxy coatings with improved adhesion ...

C. E. Locke, D. Darwin, J. Browning, M. O'Reilly

2011-01-01

89

Corrosion behavior of 2205 duplex stainless steel.  

Science.gov (United States)

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

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

1997-07-01

90

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

DEFF Research Database (Denmark)

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.

Nielsen, Lars Vendelbo

1998-01-01

91

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

International Nuclear Information System (INIS)

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

92

Corrosion protection with eco-friendly inhibitors  

International Nuclear Information System (INIS)

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)

93

Corrosion of Steel in Concrete, Part I – Mechanisms  

DEFF Research Database (Denmark)

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 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 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 initiation and propagation of corrosion of steel in concrete are outlined.

Küter, André; MØller, Per

2006-01-01

94

49 CFR 193.2625 - Corrosion protection.  

Science.gov (United States)

...2010-10-01 2010-10-01 false Corrosion protection. 193.2625 Section 193...STANDARDS Maintenance § 193.2625 Corrosion protection. (a) Each operator shall...which metallic components could, unless corrosion is controlled, have their...

2010-10-01

95

Microbial corrosion inhibition of mild steel in salty water environment  

International Nuclear Information System (INIS)

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

96

Influence of corrosion on the light steel gauge framing  

Directory of Open Access Journals (Sweden)

Full Text Available Construction technology based on the light steel gauge construction is a frame technology, allowing erecting houses in a short time. The essence of this technology is using panels of light steel galvanized perforated and non-perforated profile, which form the metal frame of the building. There are many characteristics of LSGF that have been explored for nowadays. One of the main such characteristics is corrosion resistance. Corrosion protection of light steel structures are extremely important. For the construction of steel structures, electrochemical corrosion has the main importance. Electrochemical corrosion processes take place in aqueous solutions. When the metal surface in contact with the electrolyte solution there is an interaction of the metal with charged particles of solution and the transition metal ions into the solution. It is known that stress corrosion cracking occurs under the action of tensile stresses, which cause dilation of cracks. Compressive stresses counteract cracking, causing the closure of cracks. Growth of carbon content in steel leads to growth of its resistance to stress corrosion including in environments of nitrides and hydroxides. Reducing the grain size of steel increases its resistance to cracking, which is associated with the increase of cracking of path and strength increase. In a high risk of corrosion, it is better to use solid, closed sections than lattice. Greater consumption of steel will pay off as a result of increasing physical strength of the structure. Currently, the most common method of corrosion protection is the application of coatings in a layer of paint. They concede superiority in terms of stability, plated and metal coatings, but more are available.

Maria Vladimirovna Ananina

2014-07-01

97

Corrosion protection method for reactor core tube  

International Nuclear Information System (INIS)

Palladium oxide or rhodium oxide is vapor-deposited or flame-coated on the inner surface of a tubular member of a reactor core comprising zirconium (Zr) or Zr alloy which needs corrosion protection. This suppresses diffusion of dissolved oxygen from an aqueous solution to the mother phase of the tubular member of the reactor core comprising Zr or Zr alloy. In addition, it suppresses hydrogen generated along the corrosion reaction to be absorbed to the mother phase of the Zr or Zr alloy. Further, in a coupling for a different kinds of pipes formed by bonding a first tubular member made of Zr or Zr alloy to a second tubular member comprising a stainless steel by a plastic fabrication method, when hydrogen is generated due to crevice corrosion of the joined surface of the second tubular member and the first tubular member, hydrogen is suppressed from being absorbed to the first tubular member comprising Zr or Zr alloy. (T.M.)

98

Corrosion resistance of electrical steel after calorizing  

Energy Technology Data Exchange (ETDEWEB)

Magnetically soft 20895 electrical steel is used in instrument manufacture for production of relays. According to GOST 11036-75 the magnetic properties of the steel in the annealed condition are H{sub c} = 95.0 A/m and B{sub s} = 1.32 T with an external magnetic field strength of 500 A/m. During service the magnetic properties of the steel are preserved while the life of the part depends upon the corrosion resistance of the steel used in a humid industrial atmosphere. The surface of the steel is calorized to increase the corrosion resistance. 1 ref., 1 fig., 1 tab.

Babich, S.T.; Zyabrev, A.A.; Skibina, G.V.; Kiselev, V.D.

1992-03-01

99

Role of climatic conditions on corrosion characteristics of structural steels  

International Nuclear Information System (INIS)

Corrosion behaviour of low alloy (LASS) and plain carbon (PCSS) structural steels exposed in different types of climatic conditions and nature of rust formed on their surfaces have been studied after 2 years of exposures. The test sites were chosen to represent four types of environments who strongly influence the corrosion of metals and alloys. They include (a) humid-saline, (b) humid-saline-urban (c) humid-industrial and (d) plain dry-urban environments. Mass loss, Raman spectroscopy, scanning electron microscopy and electrochemical impedance spectroscopic studies have been performed to study the corrosion behaviour and characterise the nature of rusts formed on these steels. Mass loss measurement technique has been used to determine the loss of thickness of steels during their atmospheric and salt spray exposures. Results indicate that the corrosion rate of steels is strongly influenced by the climatic conditions prevailing at the exposure sites. The presence of SO2 and salinity in the environments change the structure and protective properties of rust formed on the steels' surface. Electrochemical impedance and cyclic polarisation studies of the steels in simulated environments have been performed to understand the mechanism of corrosion in different climatic conditions

100

SYNERGIC MIXTURES PROTECTIVE ACTION AS THE FUNCTION OF WATER-SALINE MEDIUM COMPONENTS NATURE AND RATIO OF ITS CONCENTRATIONS AT CORROSION OF STEEL  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The relation between the ratio of concentrations of components in binary mixtures of adsorption and passivation effects inhibitors; its influence on the corrosion-electrochemical behavior in aqueous salt mediums (method of isomolar series) was studied. It was shown that this effect has an extremum character, where the most corrosion inhibition of anodic reaction is achieved at synergistic maximum where also achieved almost complete corrosion protection.

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2012-01-01

 
 
 
 
101

Scaling and corrosion damage of mild steel and low alloy steel in boiler feedwater  

International Nuclear Information System (INIS)

Initial corrosion of mild steel and low alloy steel in boiler feed water results in corrosion restraining oxide layers. Experiments on formation of these layers in flowing (up to 4 m/s) simulated feedwater (up to 180 deg C) are presented. According to the oxygen content of the water and depending on the hydrodynamic conditions in the tubes three different types of layers were observed. Mechanism of formation and the effect of formation are discussed. Chloride can be damaging to the corrosion restraining or protecting effects of the oxides. The different effects of chloride contaminations are discussed for the three types of layers. (author)

102

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  

Energy Technology Data Exchange (ETDEWEB)

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)

Rohr, V.

2005-10-15

103

External Corrosion in Weld Repaired Buried Steel Oil Tanks.  

Science.gov (United States)

Experimental data have been collected to reveal the effects of an internal welding repair on the external protective coating of buried steel tanks. The welding repair causes failures in the external coating and may lead to soil corrosion of buried tanks. ...

O. Varjonen

1986-01-01

104

Corrosion and protection of uranium alloy penetrators  

International Nuclear Information System (INIS)

Penetrators made from either a U--3/4 percent Ti alloy or a U--3/4 percent Mo--3/4 percent Zr--3/4 percent Nb--1/2 percent Ti alloy (''Quad'') corrode mildly in moist air, significantly in moist nitrogen, and severely in salt fog. Adequate protection was provided in moist air and nitrogen by coating with electroplated nickel, electroplated nickel and zinc with a chromate finish, and galvanized zinc with a chromate finish. In salt fog, electroplated nickel offered only temporary protection whereas galvanized zinc and electroplated nickel-zinc provided long-lasting protection. The resistance of uncoated penetrators was affected variously by dissimilar metal couplings. Aluminum protected the Quad alloy and adversely affected the U--3/4 percent Ti alloy, whereas steel enhanced localized corrosion in both. (U.S.)

105

Corrosion of steel in ionic liquids  

Directory of Open Access Journals (Sweden)

Full Text Available The corrosion behavior of 1018 carbon steel alloy has been investigated by electrochemical techniques. The ionic liquids studied were 1-butyl-3-methylimidazolium chloride ([C4mim]Cl, 1 hexyl-3-methylimidazolium hexafluorophosphate ([C6mim]PF6 1-octyl-3-methylimidazolium hexafluorophosphate ([C8mim]PF6, and 1-butyl-3-methylimidazolium bis-(trifluoromethanesulfonyl imide ([C4mim][Tf2N]. Potentiodynamic polarization and Tafel plots were used to determine the corrosion behavior of the carbon steel. Results showed that corrosion resistance of 1018 carbon steel in ionic liquids is outstanding as indicated by the low corrosion rates obtained which ranged from 3-13 µm/yr. Anodic polarization curves showed active/passive corrosion behavior of the alloy in most of the ionic liquids tested. However, ionic liquids containing chloride ions were unable to form a passive region.

Arenas M.F.

2003-01-01

106

Corrosion behavior of sensitized duplex stainless steel.  

Science.gov (United States)

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

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

1998-01-01

107

Corrosion under gamma irradiation and stress corrosion cracking behavior of unalloyed steels in a MgCl2 rich brine  

International Nuclear Information System (INIS)

Corrosion studies performed until now on a number of materials in salt brines have shown that unalloyed steels undergoing active corrosion are the most promising material for the realization of a HLW packaging serving as a barrier in a salt repository. The steels investigated exhibited only general corrosion until now so that their long-term corrosion behavior can be easier calculated that that of passive corroded alloys. Besides, the corrosion rates of the steels obtained so far lead to acceptable corrosion allowances for a thick-walled packaging. Thick-walled packagings are necessary anyway as a mechanical protection against the high rock pressure of about 40 MPa at the maximum at 1,000 m disposal depth. Two important aspects of the corrosion studies are the evaluation of the influence of gamma-radiation on the corrosion behavior of the steels and the examination of their resistance to stress corrosion cracking. Corrosion experiments performed under gamma-radiation are important because the radiolytic products formed due to the effect of radiation on salt brines might be capable of influencing the process of corrosion. The corrosion results confirmed that unalloyed steels are a promising HLW packaging material

108

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

International Nuclear Information System (INIS)

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.)

109

Corrosion and deposition of corrosion products on carbon steel and martensitic steel components of CANDU-6 reactor primary circuit  

International Nuclear Information System (INIS)

les exposed for different times in autoclaves (197, 371, 568 and 825 days), allowed us to determine the corrosion rate, the deposition and releasing of corrosion products, as well as the characteristics of the corrosive films formed. The results obtained by corrosion analysis of the carbon and martensitic steel coupons exposed in Y1-Y4 autoclaves, assembled in by-pass of CANDU-6 reactor primary circuit from Cernavoda NPP Unit 1 showed the following: - The continuous, adherent and protective oxide films were formed by generalized corrosion of structural materials. By increasing the exposure times better formation of more adherent oxides was evidenced but not any localized corrosion. The corrosion products were mainly magnetite crystalides. Their quantity increased with exposure time and was higher on samples exposed in autoclave circuits in the reactor inlet header, because the magnetite solubility is smaller, the temperature being smaller, and the coolant is probably still supersaturated in iron. The corrosion products release rate and the corrosion rate for carbon steel SA 106 gr.B decreased, while the exposure time increased. The higher values for these rates, especially at the beginning, were obtained on the samples exposed in autoclave circuits from the reactor inlet header

110

Corrosion of carbon steel under waste disposal conditions  

International Nuclear Information System (INIS)

The corrosion of carbon steel has been studied in the United Kingdom under granitic groundwater conditions, with pH between 5 and 10 and possibly substantial amounts of Cl-, SO42- and HCO3-/CO32-. Corrosion modes considered include uniform corrosion under both aerobic and anaerobic conditions; passive corrosion; localized attack in the form of pitting or crevice corrosion; and environmentally assisted cracking - hydrogen embrittlement or stress corrosion cracking. Studies of these processes are being carried out in order to predict the metal thicknesses required to give container lifetimes of 500 to 1000 years. A simple uniform corrosion model predicts a corrosion rate of around 13.4 ?m/a at 20C, rising to 69 ?m/a at 50C and 208 ?m/a at 90C. A radiation dose of 105 rad/h and a G-value of 2.8 for the production of oxidizing species would account for an increase in corrosion rate of 7 ?m/a. This model overestimates slightly the results actually achieved for experimental samples exposed for two years, the difference being due to a protective film formed on the samples. These corrosion rates predict that the container must be 227 mm thick to withstand uniform corrosion; however, they predict very high levels of hydrogen production. Conditions will be favourable for localized or pitting corrosion for about 125 years, leading to a maximum penetration of 160 mm. Since the exposure environment cannot be predicted precisely, one cannot state that stress corrosion cracking is impossible. Thus the container must be stress relieved. Other corrosion mechanisms such as microbial corrosion and hydrogen embrittlement are not considered significant

111

Rust and corrosion resistant cast steel  

International Nuclear Information System (INIS)

An austenite-ferritic chromium-nickel (molybdenum) steel alloy is used to manufacture rust and corrosion-resistant, weldable casting steel without thermal treatment. The alloy exhibits a minimum yield strength of 35-45 kg/mm2 and tensile strength of between 55-65 kg/mm2 depending on the ferrite content. (IHOE)

112

Corrosion behaviour of solution nitrided stainless steels  

International Nuclear Information System (INIS)

The case of near net shape parts made from austenitic steel X2CrNiMo17-13-2 and austenitic-ferritic steels X2CrNiMoN22-5-3 (wrought) and G-X3CrNiMoCuN26-6-3-3 (cast) is interstitially enriched with nitrogen by the diffusion-based process ''solution nitriding''. In order to obtain good corrosion resistance and mechanical properties, the solution nitriding parameters and the applied cooling time are selected so, that precipitates are avoided (X2CrNiMo17-13-2, X2CrNiMoN22-5-3). However, in case of a superimposed hydroabrasive load, the presence of nitrides in the case is found to be beneficial. The solution nitrided and the solution annealed conditions of the steels are compared with respect to their susceptibility to corrosion by means of electrochemical polarisation curves. The erosion corrosion behaviour of the materials is analysed in pilot scale flow-loop tests using particle loaded corrosive and particle loaded non-corrosive media. It is shown that ''solution nitriding'' leads to improved corrosion behaviour and/or improved erosion corrosion resistance, in particular in the case of the duplex steels. (orig.)

113

Stress corrosion of low alloy steel forgings  

International Nuclear Information System (INIS)

The catastrophic failure of a steam turbine rotor disc at Hinkley Point 'A' Power station was shown to have been caused by the growth of a stress corrosion crack to critical dimensions. This failure has promoted great interest in the stress corrosion susceptibility of medium strength low alloy steel forgings in steam environments. Consequently, initiation and growth of stress corrosion cracks of typical disc steels have been investigated in steam and also in water at 950C. Cracking has been shown to occur, predominantly in an intergranular manner, with growth rates of between 10-9 and 10-7 mm sec.-1. It is observed that corrosion pitting and oxide penetration prior to the establishment of a stress corrosion crack in the plain samples. (author)

114

Characteristics of Corrosion Product Layer Formed on Weathering Steel Exposed to the Tropical Climate of Vietnam  

Directory of Open Access Journals (Sweden)

Full Text Available The weathering steel (Corten B was exposed to out-door atmosphere of Hanoi (urban site and Donghoi (marine site. The results showed the protective ability of corrosion product layer formed on weathering steel in the initial stage. The SEM-EDX analysis detected the presence of chromium and copper in the inner layers of corrosion product formed on weathering steel. These elements improved corrosion resistance of corrosion product layers. In addition, the dense ?-FeOOH phase were appeared early in corrosion product which is detected by X-ray diffraction and Micro Raman investigations. The results of polarization and EIS measurements also demonstrated the protectiveness of the corrosion product of weathering steel.

Le Thi Hong Lien

2013-07-01

115

Corrosion behavior of wire-arc-sprayed stainless steel coating on mild steel  

Science.gov (United States)

The corrosion characteristics of a wire-are-sprayed stainless steel coating on mild steel have been investigated in regards to atomizing gases and sealing treatment. Salt spray test was performed. The corrosion behavior of the coating was observed under a microscope succesively through a cycling test of wetting and drying in a salt solution. The sealing-treated coating was found to rust faster compared with the non-sealing-treated coating; it protected the mild steel substrate against corrosion, but even it deteriorated the coating itself due to the interruption of the substrate as an anode. The air-atomized coating ruste more heavily than the nitrogen-atomized one. Four different phases were observed in the coating in regards to corrosion behavior; namely, chromium-based oxide, iron-based oxide, chromium-depleted metallic phase, and stainless steel matrix phase. It was found that the chromium-depleted metallic phase and the iron-based oxide are non-corrosion-resistant, whereas the chromium-based oxide and the stainless steel matrix phase are corrosion-resistant.

Zeng, Z.; Sakoda, N.; Tajiri, T.

2006-09-01

116

POLYETHERSULFONE COATING FOR MITIGATING CORROSION OF STEEL IN GEOTHERMAL ENVIRONMENT.  

Energy Technology Data Exchange (ETDEWEB)

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.

SUGAMA, T.

2005-06-01

117

Crevice Corrosion of 321 Stainless Steel in Sodium Chloride Solutions  

International Nuclear Information System (INIS)

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

118

Corrosion of steel tendons used in prestressed concrete pressure vessels  

International Nuclear Information System (INIS)

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

119

Corrosion of steel tendons used in prestressed concrete pressure vessels  

International Nuclear Information System (INIS)

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

120

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

International Nuclear Information System (INIS)

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.

 
 
 
 
121

Metallic corrosion of steels embedded in calcium aluminate cement mortars  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the present paper, the corrosion levels of reinforcing steels embedded in Calcium Aluminate Cement (CAC) mortars have been studied. Experiments were designed to investigate the influence of the following factors in steel corrosion: cover thickness, type of steel (carbon steel (CS) and stainless steel (SS)), temperature at mixing and curing, influence of chloride concentration, nitrite ion as corrosion inhibitor and carbonation of mortar. The reinforcing steel bars do not become more corrod...

Garci?a Andio?n, Luis; Garce?s Terradillos, Pedro; Cases Iborra, Francisco Javier; Garci?a Andreu, Ce?sar; Va?zquez Pico?, Jose? Luis

2001-01-01

122

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

International Nuclear Information System (INIS)

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 (?-Fe2O3), goethite (?-FeOOH) of intermediate particle size, lepidocrocite (?-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

123

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

International Nuclear Information System (INIS)

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

124

Principles and criteria for the evaluation of the corrosivity of atmospheric environments on steel structures  

Directory of Open Access Journals (Sweden)

Full Text Available The paper presents the environmental impact on steel structures and the corrosivity of atmospheric environments. It defines the principles and criteria for the evaluation of atmospheric-corrosivity classes, according to European standard, which were introduced in the new technical national regulations in the field of corrosion protection of steel structures. It shows the equivalence between the new corrosivity classes and the old aggressivity classes according to Romanian standard, still in force. The examples of typical environments corresponding to the corrosivity classes are also presented.

Ioan PEPENAR

2013-12-01

125

Corrosion of Steels in Steel Reinforced Concrete in Cassava Juice  

Science.gov (United States)

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.

Oluwadare, G. O.; Agbaje, O.

126

Corrosion of Steels in Steel Reinforced Concrete in Cassava Juice  

Directory of Open Access Journals (Sweden)

Full Text Available 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.

G.O. Oluwadare

2007-01-01

127

Corrosion Behavior of Low Alloy Steels Containing Manganese in Mixed Chloride Sulfate Solution  

Science.gov (United States)

The corrosion resistance of the low alloy steels was improved by the addition of Mn up to 2.0 wt pct due to grain refinement and the formation of a protective rust layer. On the other hand, the addition of 5.0 wt pct manganese decreased the corrosion resistance of low alloy steel due to the microstructural changes that hinder the formation of the protective rust layer.

Nam, Nguyen Dang; Kim, Min Jun; Kim, Jung Gu

2014-02-01

128

Corrosion of austenitic steel in leakage lithium  

International Nuclear Information System (INIS)

High-temperature lithium, which is used as the neutron source in the International Fusion Material Irradiation Facility, reacts with oxygen, nitrogen, and moisture in the atmosphere. We estimated which lithium compounds might be stable under environmental conditions by using chemical equilibrium calculations, then performed austenitic stainless steel corrosion tests with the selected lithium compounds. The lithium compounds (reagents) and a steel specimen were heated to 1120 K in an Al2O3 Tammann crucible. After the test, the steel specimen was cleaned with alcohol and water and then weighed and metallurgically examined. We found that the steel was significantly corroded in Li3N, LiOH, and Li2O2 environments. Because Li2O2 is not stable according to the chemical equilibrium calculations, corrosion by Li3N and LiOH needs to be considered in high-temperature lithium applications

129

Corrosion damage of welded steel 17247  

International Nuclear Information System (INIS)

Corrosion effects arising from welded joints of austenitic steel CSN (Czechoslovak Standard) 17247 were studied. Test specimens were taken from two heats; the one had standard chemical composition, whereas the other had elevated titanium content, viz. nearly twelvefold the carbon content. The samples were welded without preheating by manual arc welding, and successively exposed to two corrosion media: 10% ferric chloride, and a solution of copper sulfate and sulfuric acid in distilled water containing copper filings. The corrosion effect depended substantially on the previous surface finishing. Conventionally finished samples exhibited the highest corrosion resistance, electrolytically polished samples followed, whereas samples treated by cast iron grit blasting displayed the lowest resistance. Neither the base material nor the weld material exhibited tendency to intergranular corrosion in sulfuric acid. In ferric chloride solution, the weld material was only slightly affected with respect to the base material. (Z.M.). 11 refs

130

An investigation on corrosion protection layers in pipelines transporting hydrocarbons  

Directory of Open Access Journals (Sweden)

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 ?m 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.

Gabriella Bolzon

2014-10-01

131

Corrosion studies on alpha tantalum and beta tantalum coated steel  

Science.gov (United States)

Tantalum coating by sputtering, one form of physical vapor deposition (PVD), has been investigated as a replacement for chromium coatings on gun bores to protect them from erosion and corrosion due to its high ductility and high corrosion resistance in aggressive environments. When deposited as a film on steel substrates by sputtering, either alpha-Ta, beta-Ta, or a mixture of both phases have been observed under varying deposition conditions. To evaluate corrosion behavior of Ta coatings, electrochemical impedance spectroscopy and potentiodynamic polarization were conducted as a function of coating thickness. The coating porosity was observed to decrease with increasing coating thickness and hence, coatings greater than 50 mum exhibited corrosion resistance consistent with the bulk phase. Substrate roughness appeared to have little to no effect on the coating duality with respect to corrosion performance for 50 mum alpha-Ta coatings. Coatings produced in full scale processes revealed that for Ta coating (coating degradation was not observed. In contrast, while open pores were not observed with the Cr coatings, the corrosion resistance decreased as a function of time under acidic conditions, resulting in dissolution and oxidation of Cr. Initially, however, the sputtered Cr coating exhibited improved corrosion resistance over the electrodeposited one, potentially due to its oxide film. The unique properties of tantalum oxide films produced from anodic oxidation and thermal oxidation demonstrates that the nanoscale oxide films formed exhibit an ordered local structure reflecting the very compact nature that enhances its corrosion resistance.

Maeng, Sung Min

132

Corrosion protected reversing heat exchanger  

International Nuclear Information System (INIS)

A reversing heat exchanger of the plate and fin type having multiple aluminum parting sheets in a stacked arrangement with corrugated fins separating the sheets to form multiple flow paths, means for closing the ends of the sheets, an input manifold arrangement of headers for the warm end of of the exchanger and an output manifold arrangement for the cold end of the exchanger with the input air feed stream header and the waste gas exhaust header having an alloy of zinc and aluminum coated on the inside surface for providing corrosion protection to the stack

133

Corrosion inhibition of steel by bacteria  

Energy Technology Data Exchange (ETDEWEB)

Mild steel was exposed to Pseudomonas sp. S9 or Serratia marcescens in synthetic seawater. An increase in corrosion resistance over that i natural seawater was monitored by electrochemical techniques. Biological analyses were performed to characterize the system. The inhibition effect also was observed when mild steel was coated with bacteria and then immersed in synthetic seawater. When specimens coated with bacteria were transferred to a natural seawater flow system, the inhibition effect disappeared during the first 2 weeks.

Hernandez, G.; Kucera, V.; Thierry, D.; Pedersen, A. (Swedish Corrosion Inst., Stockholm (Sweden)); Hermansson, M. (Univ. of Gothenburg (Sweden). Dept. of General and Marine Microbiology)

1994-08-01

134

Metronidazole: A Corrosion Inhibitor for Mild Steel in Aqueous Environment  

Scientific Electronic Library Online (English)

Full Text Available SciELO Portugal | Language: English Abstract in english The inhibition efficiency (IE) of metronidazole (MZ)-Zn(II) system in controlling corrosion of mild steel in aqueous solution containing 60 ppm of Cl- ion has been evaluated by weight loss method. Weight loss study reveals that the formulation consisting of 140 ppm of MZ and 50 ppm of Zn(II) has 84% [...] inhibition efficiency in controlling corrosion of mild steel immersed in aqueous solution containing 60 ppm of Cl- ion. Polarization study reveals that this system as a mixed type of inhibitor controlling the cathodic and anodic reaction to an equal extent. AC impedance reveals that a protective film is formed on the metal surface. The FTIR spectra revealed that the protective film consists of Fe(II)-MZ complex.

S.M., Megalai; Y. P., Manjula; K.N., Manonmani; N., Kavitha; N., Baby.

2012-11-01

135

Metronidazole: A Corrosion Inhibitor for Mild Steel in Aqueous Environment  

Scientific Electronic Library Online (English)

Full Text Available SciELO Portugal | Language: English Abstract in english The inhibition efficiency (IE) of metronidazole (MZ)-Zn(II) system in controlling corrosion of mild steel in aqueous solution containing 60 ppm of Cl- ion has been evaluated by weight loss method. Weight loss study reveals that the formulation consisting of 140 ppm of MZ and 50 ppm of Zn(II) has 84% [...] inhibition efficiency in controlling corrosion of mild steel immersed in aqueous solution containing 60 ppm of Cl- ion. Polarization study reveals that this system as a mixed type of inhibitor controlling the cathodic and anodic reaction to an equal extent. AC impedance reveals that a protective film is formed on the metal surface. The FTIR spectra revealed that the protective film consists of Fe(II)-MZ complex.

S.M., Megalai; Y. P., Manjula; K.N., Manonmani; N., Kavitha; N., Baby.

136

Corrosion of martensitic and ferritic steels in nuclear power plants  

International Nuclear Information System (INIS)

In nuclear reactor operation martensite or ferritic corrosion resistant steels come in contact with solutions used for desactivation prior to dismantling, repairs, etc. The most frequent type of corrosion is stress corrosion cracking. For achieving good corrosion resistance material heating should be avoided in mechanical treatment. Low-resistance corrosion centres may also result from the penetration of common steel particles, eg., in grinding. The corrosion resistance test can be effected by placing filter paper soaked with the said solution on the steel surface. Corrosion centres will be evident by their blue colouring after 10 minutes. (J.B.)

137

Study of steel corrosion resistance in water coolant of WWR with boron concentration control  

International Nuclear Information System (INIS)

Presented are investigation results of corrosion effect regularities of water coolant with boron acid on different classes of steel (08Kh18N10T, EhI696, 14Kh17N2, 16GNM, 12Kh2M, 22K) at 20, 100, 200 and 300 deg C. It is determined that austenitic and martensite-ferritic stainless steels are highly corrosion resistant under investigated conditions and need protection. Pearlitic steels (12Kh2M, 16GNM, 22K and other) are liable to heavy total and pit corrosion. Corrosion resistance of pearlitic steels improves with the increase of chromium content in steels up to 5%. It is recommended to use the Kh5M steel in NPP equipment components

138

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Afolabi, Ayo Samuel

2007-01-01

139

Development of ion-plated aluminide diffusion coatings for thermal cyclic oxidation and hot corrosion protection of a nickel-based superalloy and a stainless steel  

Science.gov (United States)

This project was carried out at the University of Toronto and Cametoid Ltd of Whitby, Ontario. Ohno continuous casting; a novel net shape casting technique, was used to generate, Al-Y, Al-Ce, Al-La, and Al-Si-Y, in form of 1.6 to 1.7 mm diameter alloy wires. These alloy wires exhibited suitable properties for use as feed materials to an Ion Vapor Deposition facility. The deposition parameters were optimized to provide coatings with a compact and cohesive columnar structure with reduced porosity and diffusion barriers that were essential to ensure the success of the diffusion process in the subsequent stage. Solid-state diffusion heat treatment processes were developed in order to form the stable aluminide phases, AlNi and FeAl, on IN738 and S310 substrates, respectively. Experiments simulating the coating service conditions and environments encountered during the prospective aerospace and fuel cell applications were conducted to evaluate the performance of each aluminide coating developed during this study. Thermal cyclic oxidation and molten sulfate corrosion studies were performed on coated IN738 pins at 1050°C and 900°C, respectively, simulating the service environment of turbine engine blades and other hot section components. Molten carbonate corrosion behavior was investigated for coated S310 coupons that were immersed in, or covered with a thin film of molten carbonate, at 650°C, in air plus 30%CO2, to simulate the operating conditions of the cathode-side separator plates of molten carbonate fuel cells. The behavior of the reactive elements, yttrium, cerium, lanthanum, and silicon in enhancing the adhesion of the protective aluminum oxide scale was determined by weight variation experiments, structural examination and compositional analysis. The influence of the base material elements, nickel, chromium, and iron, on the formation of protective oxides was investigated. All coatings were found to provide significant improvement for thermal cyclic oxidation and hot corrosion protection. For protection of IN738, Al-La coatings provided the greatest protection during oxidative thermal cycling, whereas Al-Ce coatings were found to be the most effective for protection against corrosive molten sulfate environments in aerospace applications. For protection of S310 against the corrosive environments of molten carbonate fuel cells, the effectiveness of the aluminide coatings were in the sequence, from the most to the least effective, Al-La, Al-Ce, Al-Y, and Al-Si-Y Mechanisms for Lanthanum and cerium protective behavior in high temperature aluminide diffusion coatings were suggested from the results of this study combined with literature information.

Elsawy, Abdel Raouf

140

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

International Nuclear Information System (INIS)

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)

 
 
 
 
141

Corrosion of steel in hot brine  

International Nuclear Information System (INIS)

On an unalloyed steel, an oxide layer grows in aqueous solutions according to the parabolic time law. The corresponding velocity constant is independent of the chloride content of the solution. The velocity constant does not follow an Arrhenius line, but reaches a peak at a temperature of about 2500C. In the absence of chloride, the stationary corrosion rate in a neutral aqueous solution is always very low. An addition of a small quantity of chloride causes strong variations of the corrosion rate. This is to be explained by local corrosion. Holes covered by an oxide layer, however, grow towards depth only during a limited time. This effect leads to an increase in the average stationary corrosion rate particularly in concentrated chloride leaches. The design of a high-temperature apparatus for thermodynamic measurements on iron at temperatures of up to 2500C and pressures of up to 4 kbar is described. (orig./RB)

142

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

International Nuclear Information System (INIS)

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

143

49 CFR 192.461 - External corrosion control: Protective coating.  

Science.gov (United States)

...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...

2010-10-01

144

Corrosion of carbon steel in the stagnant cooling water  

International Nuclear Information System (INIS)

In the cooling water system treated with zinc-polyphosphate inhibitor, the relationship between inhibitor performance and corroded conditions of heat exchangers was studied. When cooling water system was kept in wet lay-up state, inhibitor concentration in the water jucket of heat exchangers decreased 15 ? 30 percent per week, and turbidity increased 30 ? 150 percent per week. These results show that corrosion rate of shell-plate in stagnant cooling water is more rapid than in flowing cooling water. Applied trouble discrimination method based on SiO2 ratio to the chemical composition of corrosion products, corrosion trouble was observed in shell-plates of heat exchangers. When cooling water system is kept in wet lay-up state, cooling water in the water jucket of heat exchangers is isolated for mouter system. In this perfectly closed system, zinc-polyphosphate inhibitor was not effective for protection of corrosion of carbon steel, and metal (carbon steel) dissolution occurred. However, in the perfectly closed system, since the dissolved oxygen content of the system was reduced with lapse of time, reduction process at cathodic region was stopped, so corrosion of metals seemed to be inhibited. (author)

145

Investigation into corrosion fatigue of ferritic stainless steels  

International Nuclear Information System (INIS)

The corrosion fatigue bahaviour has been studied under cyclic flexural load in air and in concentrated NaCl solutions. The materials of construction used in the test were the steels X 20 Cr 13 and X 20 CrMo 13, and the recently developed steels Inconel X 744 and PV 520 B which are used for turbine blades. The results show that the two last mentioned steels containing, in addition to 26 and 13% Cr respectively, 6 to 7% Ni are characterized by much higher corrosion fatigue resistance (107 cycles). In view of the differences found in the results with respect to the ratio between unnotched and notched specimens, on the one hand in the group X 20 Cr 13 and X 20 CrMo 13, on the other hand in the group Inconel X 744 and PV 520 B the necessity becomes evident of using for corrosion fatigue tests notched specimens too. Nitrided surface layers may exert a considerable influence in the case of short test durations, particularly in the case of the steel X 20 CrMo 13. At test durations exceeding some 100 hours, however, the protective effect of the nitrided layers disappears. (orig.)

146

Improvement of barrier properties of a hybrid sol-gel coating by incorporation of synthetic talc-like phyllosilicates for corrosion protection of a carbon steel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sol–gel coatings for corrosion protection of metals are a good alternative to toxic chromate treatments. The present work focussed on the incorporation of inorganic fillers in a sol–gel coating to improve the barrier properties of the film. Talc-like phyllosilicates obtained by hydrothermal synthesis at 160°C, 260°C and 350°C, called T160, T260 and T350 respectively, were selected as inorganic fillers. The synthetic materials showed talc lamellar structure but, in contrast with natural...

Joncoux-chabrol, Karine; Bonino, Jean-pierre; Gressier, Marie; Menu, Marie-joe?lle; Pe?be?re, Nadine

2012-01-01

147

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

International Nuclear Information System (INIS)

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

148

The assessment of corrosion type and corrosion rate of carbon steel in compacted bentonite  

International Nuclear Information System (INIS)

Carbon steel is one of the candidate materials for overpacks for high-level radioactive waste disposal in Japan. The estimation of corrosion allowance of carbon steel overpack needs to clarify the type of corrosion and the corrosion rate under repository conditions. The type of the corrosion occurring on overpacks depends on whether carbon steel is passivated or not. If carbon steel is passivated under repository conditions, localized corrosion such as pitting, crevice corrosion and stress corrosion cracking may occur under some conditions. On the other hand, if carbon steel is not passivated under repository conditions, general corrosion will occur. Passivation behavior and corrosion rate of carbon steel were investigated by electrochemical measurements under simulated repository conditions. The results of the measurements showed that carbon steel was hard to passivate in highly compacted bentonite. The immersion tests were carried out in compacted bentonite and average corrosion rates were measured from weight loss and the AC impedance of carbon steel specimens. The database of average corrosion rate were made from the data obtained by the weight loss technique. Based on the database of average corrosion rate in compacted bentonite, the relationship between average corrosion rates and test conditions were investigated. The average corrosion depth for 1000years was also estimated to be less than 5 mm. In order to simulate the accumulation of corrosion products after long term, the external current were supplied to carbon steel specimens. After the formation of corrosion products, corrosion rates were measured using AC impedance technique. The results of the measurements showed that the corrosion rate of carbon steel did not increase in the presence of corrosion products formed by external current supply. (author)

149

Corrosion Properties for Hot-dip Aluminized Steel and 304 Stainless Steel  

International Nuclear Information System (INIS)

This paper dealt with the corrosion properties of hot-dip aluminized steel and 304 type stainless steel in various corrosion environments. Pitting and crevice corrosion rates of hot-dip aluminized steel were larger than those of 304 type stainless steel, but corrosion mode of the former was general corrosion and its mode of the latter was localized corrosion. By immersion test in 3.5% NaCl solution, also, corrosion rate of hot-dip aluminized steel was faster than that of 304 type stainless steel. In anodic polarization test, corrosion potential of 304 stainless steel was noble than that of hot-dip aluminized steel and showed better passivation behavior

150

Erosion-corrosion behavior and cathodic protection of alloys in seawater-sand slurries  

Science.gov (United States)

An experimental study was conducted on the erosion-corrosion behavior of three alloys in seawater-sand slurries. The idea explored was to select a steel, a copper alloy, and a titanium alloy, which should have good resistance to abrasive wear because of high hardness (within their alloy classes). Then cathodic pro-tection would be used to protect them from corrosion. The alloys studied were 4340 steel, silicon bronze, and titanium alloy Ti-6V-4Al. Limiting conditions for cathodic protection were derived from electro-chemical polarization measurements. From erosion-corrosion tests, it was found that erosive wear by sand dominated the metal loss rates of both silicon bronze and Ti-6V-4Al. For the 4340 steel, which was the hardest material, cathodic protection provided good erosion-corrosion resistance. Supplementary measurements showed that ductility loss due to cathodically charged hydrogen in the 4340 steel was neg-ligible under the experimental conditions.

Yang, J.; Swisher, J. H.

1993-12-01

151

Pitting corrosion detection in stainless steels using ultrasounds  

International Nuclear Information System (INIS)

Passive metallic systems are able to develop in a spontaneous way a protective layer on the metallic surface that offers excellent corrosion resistance since really in a physical barrier for the reaction with the environment. However, some factors can break locally this layer, promoting one of the most insidious attack, pitting corrosion, which produces local chemical conditions that favouring the corrosive process causing defects in the material, as externals and internals ones, with a random distribution on the metal surface. In this work, ultrasounds non destructive technique has been employed using as variable the maximum amplitude of the back wall echo in order to detect this type of attack. The material employed is an austenitic stainless steel AISI 304, wherein appear several defectology distributions as superficial such as depths simulating pits. (Author)

152

Corrosion-resistant analogue of Hadfield steel  

Energy Technology Data Exchange (ETDEWEB)

The concept of alloying austenitic steels with carbon + nitrogen is used for the development of a corrosion-resistant austenitic CrMn steel having an impact wear resistance close to that of the Hadfield steel. A higher stabilization of the austenitic phase by C + N, as compared to carbon or nitrogen alone, is substantiated by ab initio calculation of the electron structure, measurements of the concentration of free electrons and calculations of the phase equilibrium. Based on these results, the compositions (mass%) Cr18Mn18C0.34N0.61 and Cr18Mn18C0.49N0.58 were melted and tested along with Hadfield steel Mn12C1.2. Mechanical tests have shown that, as compared to the Hadfield steel, the experimental steels possess a higher strength, plasticity, hardness and the same resistance to impact wear. TEM studies of the surface layer after impact treatment revealed a mixture of the amorphous phase, nanocrystals and fine-twinned austenite. At the same time, using Moessbauer spectroscopy of conversion electrons, the ferromagnetic ordering was found in the surface layer of up to 10 {mu}m in depth, which is the sign of the strain-induced martensitic phase. The hypothesis of a transition from the low-spin to the high-spin state of the iron atoms within the thin twins in austenite was proposed in order to interpret the discrepancy between TEM and Moessbauer studies. Potentiodynamic measurements and immersion tests show that the CrMnCN steels possess a significantly higher pitting potential and resistance to general corrosion in comparison with Hadfield steel.

Gavriljuk, V.G. [G.V. Kurdyumov Institute for Metal Physics, UA-03680 Kiev (Ukraine)]. E-mail: gavr@imp.kiev.ua; Tyshchenko, A.I. [G.V. Kurdyumov Institute for Metal Physics, UA-03680 Kiev (Ukraine); Razumov, O.N. [G.V. Kurdyumov Institute for Metal Physics, UA-03680 Kiev (Ukraine); Petrov, Yu.N. [G.V. Kurdyumov Institute for Metal Physics, UA-03680 Kiev (Ukraine); Shanina, B.D. [Ruhr University Bochum, D-44780 Bochum (Germany); Berns, H. [Institute for Semiconductor Physics, 03028 Kiev (Ukraine)

2006-03-25

153

Corrosion-resistant analogue of Hadfield steel  

International Nuclear Information System (INIS)

The concept of alloying austenitic steels with carbon + nitrogen is used for the development of a corrosion-resistant austenitic CrMn steel having an impact wear resistance close to that of the Hadfield steel. A higher stabilization of the austenitic phase by C + N, as compared to carbon or nitrogen alone, is substantiated by ab initio calculation of the electron structure, measurements of the concentration of free electrons and calculations of the phase equilibrium. Based on these results, the compositions (mass%) Cr18Mn18C0.34N0.61 and Cr18Mn18C0.49N0.58 were melted and tested along with Hadfield steel Mn12C1.2. Mechanical tests have shown that, as compared to the Hadfield steel, the experimental steels possess a higher strength, plasticity, hardness and the same resistance to impact wear. TEM studies of the surface layer after impact treatment revealed a mixture of the amorphous phase, nanocrystals and fine-twinned austenite. At the same time, using Moessbauer spectroscopy of conversion electrons, the ferromagnetic ordering was found in the surface layer of up to 10 ?m in depth, which is the sign of the strain-induced martensitic phase. The hypothesis of a transition from the low-spin to the high-spin state of the iron atoms within the thin twins in austenite was proposed in order to interpret the discrepancy between TEM and Moessbauer studies. Potentiodynamic measurements and immersion tests show that the CrMnCN steels possess a significantly higher pitting potensess a significantly higher pitting potential and resistance to general corrosion in comparison with Hadfield steel

154

Corrosion resistance and mechanism of steel rebar coated with three types of enamel  

International Nuclear Information System (INIS)

Highlights: ? Three types of enamel coatings have different microstructures. ? All enamel coatings improve corrosion resistance of rebar to various extents. ? Unlike damaged FBE coating, enamel coatings experience no under-film corrosion. ? Enamel coatings are less sensitive to mechanical damage than FBE coating. ? Pure/double enamel coatings have higher corrosion resistance than mixed enamel coating. - Abstract: Corrosion resistances of steel rebar with different enamel coatings, and with fusion bonded epoxy coatings were investigated in 3.5 wt.% NaCl solution by Electrochemical Impedance Spectroscopy (EIS). The sensitivity to damage of the coatings was characterized and it was found that the pure and double enamel coatings can protect the steel rebar better than the mixed enamel coating due to their denser microstructures with isolated pores. Damaged enamel coating was locally corroded, whereas corrosion at a defect often undercut the epoxy coating. The intact epoxy coating offered better corrosion protection than the enamel coatings.

155

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

Energy Technology Data Exchange (ETDEWEB)

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.

Vendelbo Nielsen, L.

1998-08-01

156

Protection potential of St3 steel in liquid cultures of soil microorganisms  

Energy Technology Data Exchange (ETDEWEB)

To determine the requirements on the protection of underground structures against microbiological corrosion, the examined the effect on the protective potential of steel of sulfate-reducing bacteria Thiobacillus thiooxidans and Aspergillus niger capable of reducing the corrosion potential in the laboratory experiments. In 10-day liquid cultures of microorganisms, they determined the corrosion losses of steel, the level of buildup of biomass by the culture, and the pH value of the medium at varying values of the applied potential.

Pritula, V.V.; Sapozhnikova, G.A.; Mogil' nitskii, G.M.; Ageeva, N.I.; Kamaeva, S.S.

1987-09-01

157

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

International Nuclear Information System (INIS)

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.

158

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

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer 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. Black-Right-Pointing-Pointer A considerably high Si content (about 40 at%) is present in the anodic passive films formed on SMSSs in 0.5 M H{sub 2}SO{sub 4} solution. Black-Right-Pointing-Pointer The high protectiveness of the anodic passive film formed on SMSSs in 0.5 M H{sub 2}SO{sub 4} solution results from a protective film consisting of a (Fe, Cr)-mixed silicate. Black-Right-Pointing-Pointer The SMSSs exhibited higher corrosion resistance than SS 304 in highly oxidizing environments. Black-Right-Pointing-Pointer 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.

Della Rovere, C.A., E-mail: carlosdrovere@gmail.com [Department of Materials Engineering, Federal University of Sao Carlos Rodovia Washington Luis, Km 235, 13565-905 Sao Carlos, SP (Brazil); Alano, J.H.; Silva, R.; Nascente, P.A.P. [Department of Materials Engineering, Federal University of Sao Carlos Rodovia Washington Luis, Km 235, 13565-905 Sao Carlos, SP (Brazil); Otubo, J. [Division of Mechanical Engineering, Technological Institute of Aeronautics Praca Marechal Eduardo Gomes, 50, Vila das Acacias, 12228-900 Sao Jose dos Campos, SP (Brazil); Kuri, S.E. [Department of Materials Engineering, Federal University of Sao Carlos Rodovia Washington Luis, Km 235, 13565-905 Sao Carlos, SP (Brazil)

2012-04-16

159

Electrochemical Studies of Stainless Steel Corrosion in Peroxide Solutions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pollution control measures have resulted in replacement of chlorine by peroxide as bleaching chemical. Change of chemical affects corrosion aspects, the suitability of existing plant metallurgy and materials of construction of bleach plants. Accordingly long term immersion and electrochemical corrosion tests were conducted on stainless steel 304L, 316L, 2205 and 6% Mo and mild steel in peroxide solutions of pH 10. The materials were tested for uniform corrosion, pitting and crevice corrosion ...

Singh, Ajay K.; Vipin Chaudhary; Sharma, A.

2012-01-01

160

Corrosion product release into sodium from austenitic stainless steel  

International Nuclear Information System (INIS)

The results of radioactive and non-radioactive corrosion product release from austenitic stainless steel are discussed. Some release mechanism are described. It was found that corrosion of austenitic stainless steel in sodium is a complex process involving several mechanisms for the different alloy constituents. Many of the hypotheses of J.R. Weeks and H.S. Isaacs concerning the role of oxygen in corrosion of steels by sodium are confirmed

 
 
 
 
161

49 CFR 192.463 - External corrosion control: Cathodic protection.  

Science.gov (United States)

...Transportation 3 2010-10-01 2010-10-01 false External corrosion control: Cathodic protection. 192.463 Section...STANDARDS Requirements for Corrosion Control § 192.463 External corrosion control: Cathodic protection. (a)...

2010-10-01

162

49 CFR 192.463 - External corrosion control: Cathodic protection.  

Science.gov (United States)

...2010-10-01 2010-10-01 false External corrosion control: Cathodic protection. 192.463 ...FEDERAL SAFETY STANDARDS Requirements for Corrosion Control § 192.463 External corrosion control: Cathodic protection....

2010-10-01

163

49 CFR 192.461 - External corrosion control: Protective coating.  

Science.gov (United States)

...2010-10-01 2010-10-01 false External corrosion control: Protective coating. 192.461 Section...FEDERAL SAFETY STANDARDS Requirements for Corrosion Control § 192.461 External corrosion control: Protective coating. (a)...

2010-10-01

164

49 CFR 192.463 - External corrosion control: Cathodic protection.  

Science.gov (United States)

...2010-10-01 2010-10-01 false External corrosion control: Cathodic protection. 192.463...FEDERAL SAFETY STANDARDS Requirements for Corrosion Control § 192.463 External corrosion control: Cathodic protection....

2010-10-01

165

49 CFR 192.461 - External corrosion control: Protective coating.  

Science.gov (United States)

...2010-10-01 2010-10-01 false External corrosion control: Protective coating. 192.461...FEDERAL SAFETY STANDARDS Requirements for Corrosion Control § 192.461 External corrosion control: Protective coating....

2010-10-01

166

Corrosion of austenitic steel in leakage lithium  

Energy Technology Data Exchange (ETDEWEB)

High-temperature lithium, which is used as the neutron source in the International Fusion Material Irradiation Facility, reacts with oxygen, nitrogen, and moisture in the atmosphere. We estimated which lithium compounds might be stable under environmental conditions by using chemical equilibrium calculations, then performed austenitic stainless steel corrosion tests with the selected lithium compounds. The lithium compounds (reagents) and a steel specimen were heated to 1120 K in an Al{sub 2}O{sub 3} Tammann crucible. After the test, the steel specimen was cleaned with alcohol and water and then weighed and metallurgically examined. We found that the steel was significantly corroded in Li{sub 3}N, LiOH, and Li{sub 2}O{sub 2} environments. Because Li{sub 2}O{sub 2} is not stable according to the chemical equilibrium calculations, corrosion by Li{sub 3}N and LiOH needs to be considered in high-temperature lithium applications.

Furukawa, Tomohiro, E-mail: furukawa.tomohiro@jaea.go.jp; Hirakawa, Yasushi; Kato, Shoichi

2013-10-15

167

78 FR 15376 - Determinations: Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea  

Science.gov (United States)

...618 (Third Review)] Determinations: Corrosion-Resistant Carbon Steel Flat Products...revocation of the countervailing duty order on corrosion-resistant carbon steel flat products...Korea and the antidumping duty orders on corrosion-resistant carbon steel flat...

2013-03-11

168

A study on the N-, S- and Cl-modified nano-TiO2 coatings for corrosion protection of stainless steel  

International Nuclear Information System (INIS)

Nano-titania coatings doped with anions of nitrogen, sulfur and chlorine have been supplied on the surface of 316L stainless steel by a sol-gel process and dip-coating technique. The measurements of XRD, SEM, ATR-IR, Raman and XPS were carried out to characterize the chemical composition and structure for the prepared samples. The corrosion performances of the coating in 0.5 M NaCl were evaluated by electrochemical impedance spectroscopy (EIS) and polarization measurements. According to the measurements of EIS and electrochemical polarization, the N-modified TiO2 nano-coatings show a highest corrosion resistance among the prepared coatings. It is revealed, from the SEM, XRD and Raman characterizations, that the surface of N-modified TiO2 nano-coatings are more compact and uniform, relatively well-crystallized and able to act as an optimal barrier layer to metallic substrates. The XPS analysis confirms the presence of low concentration of N element in two forms, atomic ?-N (interstitial state) and chemisorbed ?-N2 on the surface of TiO2 nano-coatings. It is suggested that the addition of nitrogen is beneficial to improve the compact structure and enhance the hydrophobic property

169

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

International Nuclear Information System (INIS)

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 254 SMO have also come into use for similar purposes. (Author)

170

Nitrogen addition and localized corrosion behaviour of austenitic stainless steels  

International Nuclear Information System (INIS)

Nitrogen as an alloying element has been reported to improve the localized corrosion resistance, particularly pitting, crevice and intergranular corrosion of austenitic stainless steels in chloride containing aqueous environments. The authors highlight the corrosion behaviour of nitrogen-alloyed (up to 0.56 wt%) austenitic stainless steels and compared the studies carried out by several groups. The influence of various metallurgical variables including cold working, thermal ageing, grain size and surface treatment on the pitting corrosion behaviour of the nitrogen-alloyed austenitic stainless steels is addressed. The mechanism by which nitrogen enhanced the corrosion resistance is elucidated with the help of results obtained using electrochemical and surface analytical techniques. The role of nitrogen on the formation of passive films and the semiconducting nature of passive film with nitrogen addition, are discussed to understand the corrosion resistance offered by the passive films with increasing nitrogen addition. The differences in the localized corrosion behaviour between various nitrogen alloyed stainless steels are highlighted. (author)

171

Tantalum films for protective coatings of steel  

International Nuclear Information System (INIS)

Deposition of tantalum films for protective coatings on steel by DC magnetron sputtering have been investigated. Conditions resulting in the deposition of bcc and tetragonal phases of tantalum and the evolution of the phase composition and crystallinity during the film growth from nanometers to tens of micrometers are described. Heating the substrates to only 400 deg. C resulted in the growth of pure bcc phase tantalum, which is tough and ductile and thus preferred for protective coatings, while lower temperatures promote nucleation and growth of the hard and brittle tetragonal phase. Adhesion tests by scratching with a diamond tip showed that while well adhering coatings of both phases can be obtained, the tetragonal phase films develop cracks under load, well below the critical value that results in delamination. This has important implications for application of tantalum films for protection against corrosion of steel elements subjected to mechanical stress and wear, as the cracks would locally expose the substrate to the surrounding environment. With proper choice of deposition conditions and moderate heating that does not compromise the steel properties, coatings of the preferred bcc phase of tantalum with excellent adhesion can be deposited by DC magnetron sputtering

172

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

Directory of Open Access Journals (Sweden)

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.

C. Kumar

2014-03-01

173

Materials corrosion and protection at high temperatures  

International Nuclear Information System (INIS)

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 cro- 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.)

174

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

Science.gov (United States)

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.

Sherif, El-Sayed M.

2014-02-01

175

Corrosion resistance of high-strength stainless maraging steels  

International Nuclear Information System (INIS)

Investigated are corrosion resistance and electrochemical behaviour of low-carbon (0.03% C) steels of three groups: Fe-Cr-Ni, Fe-Cr-Co, Fe-Cr-Co-Ni additionally alloyed with one of the following elements: Mo, W, Si, Cu. The sample structure and character of corrosion fracture are evaluated metalographically. The steels have been subjected to heat treatment before testing. It is shown, that alloying of the steels investigated with molybdenum, tungsten, copper and silicon does not affect their resistance to corrosion cracking. In all the steels corrosion cracking takes place with formation of a great number of cracks, propagated along the grain boundaries or subboundaries of martensite grains. Copper and molybdenum increase effectively resistance to pitting corrosion, especially in cobalt-containing steels. Molybdenum also facilitates the steel passivation

176

Influence of burnishing on stress corrosion cracking susceptibility of duplex steel  

Directory of Open Access Journals (Sweden)

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.

J. ?abanowski

2006-09-01

177

Effect of debonded interfaces on corrosion of mild steel composites in supercritical CO2-saturated brines  

Energy Technology Data Exchange (ETDEWEB)

The geologic sequestration of CO{sub 2} is a proposed method to limit greenhouse gas emissions and has been the subject of many studies in the last decade. Wellbore systems achieve isolation of the storage reservoir through a combination of steel (generally carbon steel) and Portland cement. CO{sub 2} leakage along the steel-cement interface has the potential to accelerate corrosion. We conduct experiments to assess the corrosion risk at cement-steel interface under in situ wellbore conditions. Wellbore interfaces were simulated by assemblies constructed of J55 mild steel and Portland class G (Epoxy was used in this study to separate) cement and corrosion was investigated in supercritical CO{sub 2} saturated brines, (NaCl = 1 wt%) at T = 50 C, pCO{sub 2} = 1200 psi with interface gap size = 100 {micro}m and {infinity} (open surface). The experiments were carried out in a high-pressure, 1.8 L autoclave. The corrosion kinetics were measured employing electrochemical techniques including linear polarization resistance and electrochemical impedance spectroscopy techniques. The corrosion scales were analyzed using secondary electron microscopy, back scattering electron microscopy, energy dispersive spectroscopy and x-ray diffraction. Corrosion rates decreased as time with or without interface gap. In this case corrosion rates are controlled by scale protectivity through the interface gap. Scaled steel corrosion rates were two orders of magnitude less compared with fresh steel. The corrosion scale is pseudo crystalline at the open interface. Well-crystallized scale was observed at interface gap sizes 100 {micro}m. All corrosion scales were composed of iron carbonates.

John, Han [Los Alamos National Laboratory; Carey, James W [Los Alamos National Laboratory; Zhang, Jinsuo [Los Alamos National Laboratory

2010-10-07

178

Corrosion modeling for carbon steel under oxygen depleted underground environment  

International Nuclear Information System (INIS)

In the oxygen depleted underground neutral aqueous solution environment, carbon steel reacts with H2O, producing H2 gas and forming corrosion film on the steel surface. Corrosion rate is controlled by diffusion of reaction species through corrosion film. Diffusion constants of some species working in the corrosion process were obtained from literatures. However, no data were found on the diffusion constant of H2O in iron oxides, which were estimated based on an appropriate assumption. Mass transfer model for the corrosion rate was used to simulate the corrosion rate of carbon steel. Liquid phase diffusion model of Fe2+ or H2O through pores in the corrosion film and solid phase diffusion model of H2O through corrosion film itself were examined by simulation using the spread sheet of Excel. Change in corrosion current density and corrosion loss with time and pH and temperature dependence of corrosion current density were examined. By comparing simulated results with the experimental data, it was suggested that the solid phase diffusion of H2O in the corrosion film controls the corrosion rate of carbon steel in oxygen depleted environment. (author)

179

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

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer Galvanic corrosion increases the corrosion rate of the Mg-steel joint. Black-Right-Pointing-Pointer Fe splashes lower the corrosion resistance of the joint greatly. Black-Right-Pointing-Pointer The effect of grain refinement on the corrosion behavior of the joint is slight. Black-Right-Pointing-Pointer Ni or Cu interlayer could not improve the corrosion resistance of fusion zone. Black-Right-Pointing-Pointer 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.

Liu Liming, E-mail: liulm@dlut.edu.cn [Key Laboratory of Liaoning Advanced Welding and Joining Technology, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Xu Rongzheng [Key Laboratory of Liaoning Advanced Welding and Joining Technology, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China)

2012-01-15

180

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

International Nuclear Information System (INIS)

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.

 
 
 
 
181

Steel corrosion in ammonia solutions studied by Moessbauer spectrometry  

International Nuclear Information System (INIS)

The corrosive action of diluted ammonia solutions has been thoroughly studied until 90s. A particular interest towards studying it after this time arisen from problems relating to environment protection. We have initiated a programme which involves the study of steel samples in ammoniac solutions. The steel samples were obtained from industrial Fe-C steel with C of low concentration. The surface of the samples was diamond polished, subsequently degreased and desiccated. The corrosion process of the samples was performed in an electrolytic cell with diluted ammonia solutions of concentration ranging within 10-1 - 10-4 N. Moessbauer measurements were performed at room temperature in the transmission (TMS) and conversion electron spectroscopy (CEMS) using a conventional constant-acceleration spectrometer with a 57 Co-Rh source. The TMS spectrum shows the presence of a single sextet: ?-iron. The best fit of the CEMS spectra uses an addition wide line to the sextet. The parameters of the wide line correspond to a non-stoichiometric oxide with (probably) small particles. Also the line parameters prove that we have studied the early stage of the corrosion process. All CEMS spectra show that on the surface the directions of the ?-ray and the magnetic moments are nearly perpendicular. There is a magnetic anisotropy on the surface of the samples, which remains even in the corroded samples. In contrast TMS spectrum shows that in the interior ofS spectrum shows that in the interior of the sample the magnetic moments are in a random arrangement. The result of the corrosion is the layer appearance (non-stoichiometric iron oxide) on the sample surface. The layer thickness increases with the change of the NH3 concentration from 10-1 to 10-4 N. (authors)

182

Corrosion resistance of steel thermal sprayed with tungsten carbide  

International Nuclear Information System (INIS)

The corrosion resistance of thermal-sprayed W2C + Co coatings on 40H steel both nonremelted and remelted by means of laser and TIG methods was investigated. The investigations were carried out in 'salt spray' environment, moist SO2 and inhibited HCl solution. The coatings did not improve the corrosion resistance of steel. The remelted coatings were more effective than nonremelted. (author)

183

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

DEFF Research Database (Denmark)

A reinforced mortar specimen that allows potential measurements and electrochemical impedance spectroscopy (EIS) immediately after preparation was designed and tested. The specimen consists of a mortar cylinder with a central rebar and a concentric arrangement of embedded Ru/Ir activated titanium wires. The wires can act as both reference and counter electrode during EIS and, thus, no external electrode is required. The defined geometry solves reproducibility problems involved with application of an external reference electrode for EIS. Changes of the electromotive force (EMF) between rebar and titanium wires can be monitored immediately after preparation. The wire arrangement also allows investigation of local changes in the bulk mortar by EIS or by measuring the potential development of the titanium wires versus an external standard electrode. The specimen design was evaluated in an 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.

Küter, Andre; Geiker, Mette Rica

2005-01-01

184

Corrosion Behavior of Nitrogen Ion Implanted Stainless Steel  

International Nuclear Information System (INIS)

The corrosion behavior of nitrogen ion implanted 440C stainless steel was studied as a practical application of ion implantation. 440C stainless steel was subjected to the same implantation condition which showed the significant improvement of corrosion resistance of a high purity iron. The composition and structure of implanted layer were examined. The corrosion tests of the samples were performed in deaerated 1N H2SO4 and 0.1M NaCl aqueous solution using a potentiodynamic polarization method. The corrosion mechanisms of nitrogen ion implanted 440C stainless steel were investigated

185

Joint effect of temperature, stress states and sulfur ions on the CO2 corrosion behavior of N80 tubing steel  

Directory of Open Access Journals (Sweden)

Full Text Available The joint influence of solution temperature, stress states and sulfur ions on the CO2 corrosion behavior of N80 tubing steel, were investigated by using electrochemical impedance spectroscopy (EIS. The results showed that the addition of sulfur ions into the solution and with the introducing of stress into carbon steel can decrease the protective effect of the corrosion scale on the substrate at low temperature; and the protective effect enhances at high temperatures. The corrosion scale formed on N80 steel in stratum water containing sulfur ions are mainly consisted of FeCO3 and FeS.

J. B. Li, X. Hou, M.S Zheng, J. W. Zhu

2007-08-01

186

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

International Nuclear Information System (INIS)

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

187

The influence of carbon steel microstructure on corrosion layers An XPS and SEM characterization  

International Nuclear Information System (INIS)

Corrosion related failures in the oil and gas industry represent a very serious and costly problem. The successful application of carbon steels in oil and gas pipelines and production tubulars in CO2 containing environments depends mainly on either the formation of protective corrosion product film or the use of corrosion inhibitors. Both laboratory experiments and field experience have shown that the protective properties and adherence of the film may vary significantly for carbon steels with apparently the same composition and microstructure. In the present work, characteristics such as morphology, thickness and composition of corrosion layers formed on carbon steel with two different microstructures (annealed, and quenched and tempered) have been studied by means of scanning electron microscopy (SEM), electron dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS). The corrosive media was a deoxygenated 5% NaCl solution, saturated with CO2 at 40 deg. C and pH 6. The effect of the addition of benzimidazol as a corrosion inhibitor has also been analyzed. It is concluded that the microstructure of steel influences the inhibitor efficiency and the properties of the corrosion layers, such as morphology and proportion of the various chemical compounds present

188

Corrosion of martensitic steels in flowing Pb17Li  

International Nuclear Information System (INIS)

Corrosion tests carried out in the CAMILLE loop at 475 deg C evidence that the corrosion rate of martensitic steels is strongly dependent on Pb17Li velocity, suggesting that the rate limiting step is diffusion of dissolved elements in the laminar sub-layer. The comparison of various corrosion data available in the literature corroborates this result. The other parameters also investigated in these studies (metallurgical state, surface preparation, type of steel, position of specimens) comparatively seem to be of minor importance

189

A Study of Localized Corrosion in Supermartensitic Stainless Steel Weldments  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This doctoral thesis is concerned with pitting corrosion in super martensitic stainless steel (SMSS) weldments in slightly sour service. Thee main objective with the present thesis has been to find out why pitting corrosion occurs in the heat affected zone (HAZ) at ambient rather than at elevated temperatures and how the corrosion mechanism depends on the welding process. The thesis is divided into six parts. Part I gives a general introduction to martensitic stainless steels, focusing on the...

Enerhaug, Jakob

2002-01-01

190

The anaerobic corrosion of carbon steel in concrete  

International Nuclear Information System (INIS)

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

191

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

Energy Technology Data Exchange (ETDEWEB)

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.

Bradshaw, Robert W.; Clift, W. Miles

2010-11-01

192

Corrosion of steel in concrete in cooling water walls. Report part 2 - Effects of the relative humidity on chlorine-initiated corrosion of the reinforcing steel  

International Nuclear Information System (INIS)

Steel in concrete is protected against corrosion by the high pH value of the concrete. The passivity can however be broken if chloride ions penetrate into the concrete. It is presumed that a certain amount of chloride is needed to activate the steel. This value is called the threshold level. Even though many attempts have been performed no reliable value has been found. One of the reasons for this is probably that the threshold value is influenced by the humidity of the concrete. At very high humidity the transport of oxygen to the steel surface is slow and at low humidity the electrical resistance increases. The aim of this investigation has been to determine at what humidity the corrosion rate reaches its highest value. With this as a background new tests can be performed to predict the chloride threshold value. The results indicate that it most probably do exist a threshold value for each concrete quality. At chloride contents above the threshold value the steel looses its passivity. If severe corrosion takes place or not is however strongly dependent on the humidity of the concrete. In a close interval around 95 % relative humidity the steel is attacked by pitting corrosion when the threshold value is exceeded. At lower and higher humidity the passivity is incomplete and the corrosion rate in most cases marginal. Future investigations concerning chloride threshold values is recommended to be performed at a relative humidity of 95 % and by using reference samples according to proposed procedure.

193

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

International Nuclear Information System (INIS)

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

194

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

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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.

Gvozdenovi? Milica M.

2005-01-01

195

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

Science.gov (United States)

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.

Tang, Fujian

196

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

Science.gov (United States)

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.

Stoulil, J.; Ka?ok, J.; Kou?il, M.; Parschová, H.; Novák, P.

2013-11-01

197

49 CFR 192.461 - External corrosion control: Protective coating.  

Science.gov (United States)

... External corrosion control: Protective coating...of external corrosion control must— (1) Be applied...underfilm migration of moisture; (3) Be sufficiently...type must also have low moisture absorption and high...effective corrosion control must be...

2010-10-01

198

The Corrosion Behavior of Cold Sprayed Zinc Coatings on Mild Steel Substrate  

Science.gov (United States)

Zinc and its alloy coatings have been used extensively for the cathodic protection of steel. Zinc coating corrodes in preference to the steel substrate due to its negative corrosion potential. Numerous studies have been conducted on the corrosion behavior of zinc and its alloy coatings deposited using several techniques viz., hot dip galvanizing, electrodeposition, metalizing or thermal spray etc. Cold spray is an emerging low temperature variant of thermal spray family which enables deposition of thick, dense, and pure coatings at a rapid rate with an added advantage of on-site coating of steel structures. In the present study, the corrosion characteristics of cold sprayed zinc coatings have been investigated for the first time. In addition, the influence of heat treatment of zinc coating at a temperature of 150 °C on its corrosion behavior has also been addressed.

Chavan, Naveen Manhar; Kiran, B.; Jyothirmayi, A.; Phani, P. Sudharshan; Sundararajan, G.

2013-04-01

199

A Novel Hydrazinecarbothioamide as a Potential Corrosion Inhibitor for Mild Steel in HCl  

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Full Text Available 2-(1-methyl-4-((E-(2-methylbenzylideneamino-2-phenyl-1H-pyrazol-3(2H-ylidene-hydrazineecarbothioamide (HCB was synthesized as a corrosion inhibitor from the reaction of 4-aminoantipyrine, thiosemicarbazide and 2-methylbenzaldehyde. The corrosion inhibitory effects of HCB on mild steel in 1.0 M HCl were investigated using potentiodynamic polarization (PDP and electrochemical impedance spectroscopy (EIS. The results showed that HCB inhibited mild steel corrosion in acidic solution and inhibition efficiency increased with an increase in the concentration of the inhibitor. The inhibition efficiency was up to 96.5% at 5.0 mM. Changes in the impedance parameters suggested that HCB adsorbed on the surface of mild steel, leading to the formation of a protective film. The novel corrosion inhibitor synthesized in the present study was characterized using Fourier transform infrared spectroscopy (FTIR and nuclear magnetic resonance (NMR spectral data.

Abu Bakar Mohamad

2013-04-01

200

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

Energy Technology Data Exchange (ETDEWEB)

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 (Fe{sub 3-x}O{sub 4}), maghemite ({gamma}-Fe{sub 2}O{sub 3}), goethite ({alpha}-FeOOH) of intermediate particle size, lepidocrocite ({gamma}-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.

Jaen, Juan A. [Universidad de Panama, Centro de Investigaciones con Tecnicas Nucleares (Panama); Sanchez de Villalaz, Mariela [Universidad Tecnologica de Panama, Laboratorio de Metalurgia (Panama); Araque, Lilibeth de [Universidad de Panama, Centro de Investigaciones con Tecnicas Nucleares (Panama); Bosquez, Agnes de [Universidad de Panama, Departamento de Quimica (Panama)

1997-09-15

 
 
 
 
201

Comparative investigation of corrosion resistance of steel reinforcement in alinite and Portland cement mortars  

Energy Technology Data Exchange (ETDEWEB)

The corrosion resistance of steel-reinforced mortar specimens made from alinite cement was investigated using ordinary Portland cement (OPC) specimens as reference. The specimens were prepared and exposed in three different environments: continuous exposure in tap water, interrupted exposure in tap water, and interrupted exposure in 3.5% NaCl solution. The steel weight loss and the half cell potential were measured vs. exposure time, up to the age of 12 months. Pore solution extraction and analysis and porosity determination were also performed. In continuous exposure in tap water, alinite cement provided adequate protection against corrosion. In interrupted exposure in tap water, a higher corrosion was observed for alinite cement compared to OPC. In the case of interrupted exposure in 3.5% NaCl solution, the simultaneous action of free chlorides and oxygen resulted in the depassivation of steel reinforcing bars in alinite and Portland cement mortars, and led to severe corrosion effect.

Kostogloudis, G.C.; Kalogridis, D.; Ftikos, C. [National Technical Univ., Athens (Greece); Malami, C.; Georgali, B.; Kaloidas, V. [Heracles General Cement Co., Athens (Greece)

1998-07-01

202

Inhibition of salt precipitation, corrosion and corrosion fatigue of steel in neutral environments  

International Nuclear Information System (INIS)

Processes of salt precipitation, corrosion under dynamic and static conditions, are studied as well as corrosion fatigue of 20 and 40Kh steels in neutral aqueous media without and with the addition of compounds of several classes. The solution of calcium bicarbonate with the initial concentration [Ca(HCO3)2]=1.3 g/l and 3% NaCl solution in distilled water are used for investigation. The effectiveness index of salt precipitation inhibitor is determined by the change in the rate of calcium bicarbonate transformation into carbonate. The combination of results obtained permits to make the conclusion that tripolyphosphate and pyrophosphoric acid are rather perspective inhibitors of complex effect with low protective concentrations

203

Role of FeS in protective action of iron corrosion inhibitors  

International Nuclear Information System (INIS)

Adsorption of hexanol on iron sulfide, sodium capronate and AB catamine was studied. Influence of FeS on the AB catamine protective action in the course of steel 10 corrosion in 1M solution of NaCl was considered. High adsorption specific capacity of FeS as regards surfactants was ascertained. Adsorption of the inhibitor by iron sulfide reduces its protective action during steel corrosion, although does not lead to its compolete loss, which indicates participation of colloid particles in the formation of protective film on metal

204

Corrosion monitoring of reinforcing steel in RC beam by an intelligent corrosion sensor  

Science.gov (United States)

Health degradation by corrosion of steel in civil engineering is a persistent problem. Structural health monitoring techniques can lead to improve estimates of structural safety and serviceability effectively. The corrosion sensor and the monitoring method have been explored and applied in RC beam's corrosion monitoring. A novel five-electrode corrosion sensor has been developed to provide the platform for corrosion monitoring of the steel bar in concrete beam by electrochemical method. Half-cell potential of the RC beam has been measured to identify the corrosion statues of the steel bar qualitatively. Galvanostatic step method has been used to excite the steel-concrete system and the transient response of the system has been obtained. The data of the transient response has been analyzed by segmented method. Some important electrochemical parameters have been extracted by this method. The results show it is effectively to analyze the data of the transient response by segmented method.

Qiao, Guofu; Hong, Yi; Ou, Jinping

2009-07-01

205

Flow Assisted Corrosion and Erosion-Corrosion of RAFM Steel in Liquid Breeders  

International Nuclear Information System (INIS)

Full text: Study on flow assisted corrosion (FAC) and erosion-corrosion of RAFM JLF-1 steel (Fe-9Cr-2W-0.1C) in liquid breeders of Li, Pb-17Li and Flinak was carried out. It was found that the alloying element of Fe and Cr in the JLF-1 steel was commonly dissolved into these melts. The compatibility model of the JLF-1 steel in liquid breeders was developed. The mass loss of the specimens in the corrosion experiments was evaluated by the model. The effect of erosion-corrosion on the total mass loss of the steel in the liquid metals could be larger than that of FAC estimated by mass transfer calculation. The mass loss of the steel by electrochemical corrosion might be larger than that by the FAC in the Flinak. (author)

206

Investigation of Carbon steel corrosion in water base drilling mud  

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Full Text Available Carbon steel, the most widely used engineering material, accounts for approximately 85%, of the annual steel production worldwide. Despite its relatively limited corrosion resistance, carbon steel is used in large tonnages in marine applications, nuclear power and fossil fuel power plants, transportation, chemical processing, petroleum production and refining, pipelines, mining, construction and metal-processing equipment. This paper Investigate Carbon steel corrosion in water. The corrosion rate in production and casing pipes in water base drilling mud (packer fluid, different salt concentration (100gm/L , 150 gm/L , 200gm/L have been used and different temperature (30co , 50 co , 70 co have been investigated. Weight loss and polarization methods were applied. The results indicate that the corrosion rates decrease with the increasing of salt concentration while the corrosion rates increase with increasing of temperature

Fadhil Sarhan Kadhim

2011-01-01

207

Corrosion behavior of duplex stainless steel in sulphuric acid  

International Nuclear Information System (INIS)

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)

208

Sensitization-induced localized corrosion in austenitic stainless steels  

International Nuclear Information System (INIS)

Sensitization-induced localized corrosion can be broadly classified into two categories, namely, intergranular corrosion (IGC) and intergranular stress corrosion cracking (IGSCC). These two forms of corrosion affect several grades of austenitic stainless steels and nickel based alloys, and are commonly observed in power, chemical and petrochemical industries. Majority of corrosion failures of critical austenitic stainless steel components in these industries can be attributed to IGC and IGSCC. It is therefore essential to monitor the extent and rate of these localized forms of corrosion periodically. This paper will discuss the following issues related to sensitization induced localized corrosion in austenitic stainless steels: low temperature sensitization (LTS) in austenitic stainless steels, modification to ASTM test for evaluation of IGC susceptibility in austenitic stainless steels and NDT methods (UT and ECT) for monitoring IGC and IGSCC in austenitic stainless steels. Irradiation-assisted stress corrosion cracking (IASCC), attributed to solute segregation (Si, P) and chromium depletion at grain boundaries induced by irradiation will also be discussed. (author)

209

Corrosion monitoring of reinforcing steel in concrete by electrochemical sensors  

Science.gov (United States)

Health degradation by corrosion of steel in civil engineering, especially in rough environment, is a persistent problem. Structural health monitoring (SHM) techniques can lead to improved estimates of structural safety and serviceability. A novel all solid state-current confined corrosion sensor has been developed to provide the platform for corrosion monitoring of the steel bar in concrete beam by electrochemical method. Finite element method has been used to certify the current confined effect of the sensor. The sensors have been used in concrete beams to monitor the corrosion of the steel bar. Also, half-cell potential of the beam has obtained. The results shows that the corrosion sensor can effectively confine the current in the fixed area which is 45mm×?×Dsteel bar and the monitoring results of the corrosion sensor are accurate.

Qiao, Guofu; Hong, Yi; Ou, Jinping

2010-04-01

210

Hot Corrosion Behavior of HVOF Sprayed Coatings on ASTM SA213-T11 Steel  

Science.gov (United States)

Cr3C2-NiCr, NiCr, WC-Co and Stellite-6 alloy coatings were sprayed on ASTM SA213-T11 steel using the HVOF process. Liquid petroleum gas was used as the fuel gas. Hot corrosion studies were conducted on the uncoated as well as HVOF sprayed specimens after exposure to molten salt at 900 °C under cyclic conditions. The thermo-gravimetric technique was used to establish the kinetics of corrosion. XRD, SEM/EDAX and EPMA techniques were used to analyze the corrosion products. All these overlay coatings showed a better resistance to hot corrosion as compared to that of uncoated steel. NiCr Coating was found to be most protective followed by the Cr3C2-NiCr coating. WC-Co coating was least effective to protect the substrate steel. It is concluded that the formation of Cr2O3, NiO, NiCr2O4, and CoO in the coatings may contribute to the development of a better hot-corrosion resistance. The uncoated steel suffered corrosion in the form of intense spalling and peeling of the scale, which may be due to the formation of unprotective Fe2O3 oxide scale.

Sidhu, H. S.; Sidhu, B. S.; Prakash, S.

2007-09-01

211

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

Science.gov (United States)

...2010-04-01 2009-04-01 true Corrosion inhibitors used for steel or tinplate...Adjuvants and Production Aids § 178.3300 Corrosion inhibitors used for steel or tinplate. Corrosion inhibitors may be safely used for...

2010-04-01

212

Electrochemical Studies of Stainless Steel Corrosion in Peroxide Solutions  

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Full Text Available Pollution control measures have resulted in replacement of chlorine by peroxide as bleaching chemical. Change of chemical affects corrosion aspects, the suitability of existing plant metallurgy and materials of construction of bleach plants. Accordingly long term immersion and electrochemical corrosion tests were conducted on stainless steel 304L, 316L, 2205 and 6% Mo and mild steel in peroxide solutions of pH 10. The materials were tested for uniform corrosion, pitting and crevice corrosion and attack around the weld area. Corrosion attack estimated from long term immersion tests is found in agreement, by and large, with that analyzed from electrochemical test. E-pH diagrams drawn for water-peroxide system have been used to understand the corrosivity of the peroxide media. An attempt has been made to suggest a suitable material of construction for handling the test media on the basis of degree of corrosion attack on them and their cost and the mechanical properties.

Ajay K. Singh

2012-03-01

213

Corrosion of vessel steel during its interaction with molten corium  

Energy Technology Data Exchange (ETDEWEB)

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.

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

214

Corrosion of vessel steel during its interaction with molten corium  

International Nuclear Information System (INIS)

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

215

Corrosion-resistant Foamed Cements for Carbon Steels  

Energy Technology Data Exchange (ETDEWEB)

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 surfaces; 2) inhibiting the cathodic reactions at the corrosion site of CS; 3) extending the coverage of cement over CS surfaces; and, 4) improving the adherence of the cement to CS surfaces. Thus, the CS’s corrosion rate of 176 milli inch/per year (mpy) for 1 wt% FA-foamed cement without AP was considerably reduced to 69 mpy by adding only 2 wt% AP. Addition of AP at 10 wt% further reduced this rate to less than 10 mpy.

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

2012-12-01

216

Corrosion Behaviour of Nickel Plated Low Carbon Steel in Tomato Fluid  

Directory of Open Access Journals (Sweden)

Full Text Available This research work investigated the corrosion resistance of nickel plated low carbon steel in tomato fluid. It simulated the effect of continuous use of the material in a tomato environment where corrosion products are left in place. Low carbon steel samples were nickel electroplated at 4V for 20, 25, 30 and 35 mins using Watts solution.The plated samples were then subjected to tomato fluid environment for for 30 days. The electrode potentials mV (SCE were measured every day. Weight loss was determined at intervals of 5 days for the duration of the exposure period. The result showed corrosion attack on the nickel- plated steel, the severity decreasing with the increasing weight of nickel coating on substrate. The result showed that thinly plated low carbon steel generally did not have any advantage over unplated steel. The pH of the tomato solution which initially was acidic was observed to progress to neutrality after 4 days and then became alkaline at the end of the thirty days test (because of corrosion product contamination of the tomatocontributing to the reduced corrosion rates in the plated samples after 10 days. Un-plated steel was found to be unsuitable for the fabrication of tomato processing machinery without some form of surface treatment - thick nickel plating is suitable as a protective coating in this environment.

Oluleke OLUWOLE

2010-12-01

217

Corrosion protection of metals by silane surface treatment  

Science.gov (United States)

The need for toxic chromate replacements in metal-finishing industries has prompted an intensive search for replacement technologies in recent years. Among the replacements that have been proposed, those that are based upon the use of organofunctional silanes rank very high in terms of performance, broad applicability as well as ease of application. This dissertation presents a four-part work: (1) structural characterization of silane films on metals, (2) mechanism studies of silane-treated metal systems, (3) development of water-based silane systems, and (4) measurements of other properties of silane films. In part 1, silane films, i.e., bis-[triethoxysilylpropyl]tetrasulfide (bis-sulfur silane) and bis-[trimethoxysilylpropyl]amine (bis-amino silane) were deposited on AA 2024-T3 and were characterized mainly using reflection-absorption Fourier-transform infrared spectroscopy (FTIR-RA) and electrochemical impedance spectroscopy (EIS) techniques. In part 2, the mechanistic study of corrosion protection of AA 2024-T3 by bis-sulfur silane film was carried out. In summation, the following two factors play critical roles in the corrosion protection of AA 2024-T3: (1) the formation of a highly crosslinked interfacial layer, and (2) high water resistance of silane films. The former inhibits corrosion in the following two ways: (1) blocking favorable sites for water adsorption by the formation of AlOSi bonds at the interface which effectively reduces the tendency of aqueous corrosion; and (2) bonding tightly to the metal and thus restricting transportation of the existing corrosion products away from their original sites which hinders pit growth. It should be noted that a high density of AlOSi bonds can be obtained employing bis-silanes rather than mono-silanes. A high water resistance makes water penetration difficult in silane films. This is essential for preventing AlOSi bonds from hydrolysis. In part 3, test results for newly-developed water-based silane systems were reported. The major advantage of these silane systems is that they are highly miscible with water, which makes them more industrially acceptable than alcohol-based silanes. Test results demonstrated that these silanes provide excellent corrosion protection as well as paint adhesion on a variety metals including, Al alloys, Zn-coated steels, carbon steels, and stainless steels. Part 4 reported several other properties of silane films, such as resistivity/conductivity, mechanical properties, and thermal stabilities of silane films. (Abstract shortened by UMI.)

Zhu, Danqing

218

Synthesis of the functional derivatives of thioglycolic acid and research of influence of structural factors on their protective properties at corrosion of steel  

International Nuclear Information System (INIS)

Full text: Results of influence of structural factors investigation on protective properties of some mono-and di-replaced functional derivatives with general formulas HS-CH2COOH and R'-S-CH2-COOR, synthesized on the basis of thioglycolic acids (TGA) have been considered. It is established, that in biphasic sour system 0.04% water solution CH3COOH-kerosene, all the investigated compounds-both mono and di-replaced, process inhibitor properties. Influence of the nature, structure and lengths of radicals on efficiency of obtained compounds is also established. It is revealed, that among the investigated connections, bi-replaced derivatives of TGA: cyclohexyl propoxycarbonylmethyl sulphide and deputy ether butoxycarbonyymethyl this iconic acids are the most effective inhibitors. As well it is revealed, that all the mono-replaced derivatives of TGA, expect the compound with formula HS-CH2-COOCH2-OH, in biphasic neutral system 3% water solution NaCI- kerosene stimulate corrosion process St-3.It is established, that above-stated di-replaced derivatives TGA also process inhibitor properties in neutral system, however efficiency of these compounds turned to be much less, than in sour system

219

Electrochemical study of the crevice corrosion resistance of stainless steels: example of Cr-Mo ferritic steels  

International Nuclear Information System (INIS)

The measurement of stainless steel depassivating pH enables the crevice corrosion resistance to be evaluated. It is concluded that: Mo is more efficient than Cr; the classification of the stainless steel types is not the same for pitting and crevice corrosion resistance; crevice corrosion resistance of Cr-Mo ferritic steels is similar to that of Cr-Ni-Mo austenitic steels

220

Corrosion protective coating for metallic materials  

Science.gov (United States)

Corrosion protective coatings for metallic materials, particularly aluminum and aluminum alloys, produced with simple, low-cost equipment and materials other than toxic metals or metal salts, or metal cyanides is disclosed. The metallic material is cleaned, degreased, and deoxidized, the surface is converted to a substantially alkaline condition, and the surface is chemically sealed with inorganic metal compounds. 1 fig.

Buchheit, R.G.; Martinez, M.A.

1998-05-26

 
 
 
 
221

Bacterial corrosion in marine sediments: influence of cathodic protection  

International Nuclear Information System (INIS)

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)

222

Corrosion inhibition by ion beam induced vacuum carburization of tool steel  

Science.gov (United States)

Drastic improvements of corrosion properties of a highly corrosive carbon steel material has been observed after N + ion bombardment and simultaneous vacuum vaporization of silicon oil. The combined effect of ion irradiation and controlled deposition results in a compact carbon-silicon layer, which due to the dynamic ion beam mixing process, is firmly attached to the substrate surface. Aqueous corrosion studies were done in both acetic acid and NaCl solutions. Improved corrosion properties were found by measuring the incubation time, i.e. the time of exposure in the liquid necessary to induce the first signs of corrosion attack. The improved corrosion characteristics are explained by the creation of the nonporous and highly adhesive carbon-silicon film acting as a protecting layer against chemical attack.

Braun, M.

1989-03-01

223

AFM study of steel corrosion in aqueous solutions in concrete  

Directory of Open Access Journals (Sweden)

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.

Díaz-Benito, B.

2011-03-01

224

Corrosion study of two ferritic steels by liquid lead circulating in a thermoshyphon: Model research  

International Nuclear Information System (INIS)

In the field of the investigations concerning direct contact for Molten Salts Reactors, a study of the behaviour of ferritic steels in flowing liquid lead has been untertaken. For this purpose, two thermal convection loops were constructed, respectively of Chromesco 3 and EM 12 steels. They operated during 3000 h, without plugging, with a hot leg temperature of 5500C, a ?T of 800C and a lead flow velocity of 0.1 m/s. It appears that the hot leg corrosion and the associated deposition in the cold leg are significantly more pronounced for Chromesco 3 compared to EM 12 steel. A unsophisticated model, only taking into account the phenomena of dissolution-deposition, liquid state diffusion and transport of the dissolved metal in liquid lead allows to explain qualitatively the results obtained with Chromesco 3 steel. Concerning EM 12 steel, the formation of a protective chromium rich oxide layer is probably involved in the corrosion mechanism. (orig.)

225

Corrosion fatigue behaviour of ion nitrided AISI 4140 steel  

Energy Technology Data Exchange (ETDEWEB)

Machine components suffer from corrosion degradation of fatigue characteristics and improvement can be attained by the application of a nitriding treatment, particularly to low alloy steels. In the present study, the effect of ion nitriding on corrosion fatigue performance of AISI 4140 steel has been investigated by conducting a series of rotary bending corrosion fatigue tests at 95 Hz, in 3% NaCl aqueous solution. Hourglass shaped, 4 mm diameter fatigue specimens were ion nitrided at 748 K for 1, 3, 8 and 16 h prior to the tests. It was observed that distinct fatigue limit behaviour of ion nitrided steel in air completely disappeared in corrosive environment besides severe degradation in fatigue characteristics. An improvement reaching to 60% in corrosion fatigue strength can be attained by successive ion nitriding practice based on a fatigue life of 10{sup 7} cycles. An attempt was made to establish an empirical relationship between corrosion fatigue strength and relative case depth, which considers the size of the ion nitrided specimen. It was also determined that a power relationship holds between corrosion fatigue strength and fatigue life of ion nitrided steel. The presence of white layer has resulted in additional improvement in corrosion fatigue resistance, and it was observed that corrosion fatigue cracks were initiated dominantly under the white layer by pit formation mechanism. (orig.)

Genel, K. [Sakarya Univ., Adapazari (Turkey). Mech. Eng. Dept.; Demirkol, M.; Guelmez, T. [Faculty of Mechanical Engineering, Istanbul Technical University, Guemuessuyu, 80191, Istanbul (Turkey)

2000-08-31

226

Corrosion fatigue behaviour of ion nitrided AISI 4140 steel  

International Nuclear Information System (INIS)

Machine components suffer from corrosion degradation of fatigue characteristics and improvement can be attained by the application of a nitriding treatment, particularly to low alloy steels. In the present study, the effect of ion nitriding on corrosion fatigue performance of AISI 4140 steel has been investigated by conducting a series of rotary bending corrosion fatigue tests at 95 Hz, in 3% NaCl aqueous solution. Hourglass shaped, 4 mm diameter fatigue specimens were ion nitrided at 748 K for 1, 3, 8 and 16 h prior to the tests. It was observed that distinct fatigue limit behaviour of ion nitrided steel in air completely disappeared in corrosive environment besides severe degradation in fatigue characteristics. An improvement reaching to 60% in corrosion fatigue strength can be attained by successive ion nitriding practice based on a fatigue life of 107 cycles. An attempt was made to establish an empirical relationship between corrosion fatigue strength and relative case depth, which considers the size of the ion nitrided specimen. It was also determined that a power relationship holds between corrosion fatigue strength and fatigue life of ion nitrided steel. The presence of white layer has resulted in additional improvement in corrosion fatigue resistance, and it was observed that corrosion fatigue cracks were initiated dominantly under the white layer by pit formation mechanism. (orig.)

227

Innovative steels for structural and corrosion resistance applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The attention towards innovative steels at limited cost increased significantly in the last years. The research focused mainly in the development of new high strength steels where a combination of elevated mechanical properties, good formability and weldability is required and of duplex stainless steels if high corrosion resistance and mechanical properties are demanded. The possibility to design new light components thanks to the higher strength of such steels, the substitution of expensive ...

Baldo, Silvia

2011-01-01

228

Investigation of Fecraly Coating on Corrosion Behaviour of Mild Steel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Agboola, Joseph B.

2009-01-01

229

Hardfaced welded protective coatings for corrosion and wear stresses  

International Nuclear Information System (INIS)

As a rule, materials which resist even extremely high corrosion and wear stresses, are very expensive and/or difficult to work. For this reason many efforts are made to avoid massive types of construction, if possible, and only to provide the stressed surface with a suitable protective coating. An economically favourable alternative, which is particularly used for thick-walled components, is hardfacing welding. With this it is possible to use coated basic materials, eg: unalloyed steels as the sources of mechanical strength, and to coat the surface with different hardfacing welding processes according to the stresses on it. (orig.)

230

Corrosion resistance of Si- and Al-rich steels in flowing lead-bismuth  

International Nuclear Information System (INIS)

Corrosion resistance of Si- and Al-rich steels in lead-bismuth flow was studied experimentally. The specimens of SUH3 (10Cr-1Mo-2Si), NTK04L (18Cr-3Al) and Recloy10 (18Cr-1Al-1Si) were exposed to flowing lead-bismuth for 500-2000 h. After the exposure, metallurgical analysis of their surfaces and weight loss measurement of the specimens were carried out. The surface of the Si-rich steels, SUH3, was smooth with no liquid metal corrosion. Double-oxide layers were observed on the surface of SUH3 steel, where an inner layer might serve as a barrier for the liquid metal corrosion attack, while the outer layer could detach from the surface. An initial metallic luster of the surfaces remained on NTK04L and Recloy 10 steels after the exposure. An Al-rich single layer was formed and stuck on the steel surfaces. This layer protected the steel matrix from the corrosion. The weight losses of these Al-rich steels, NTK04L and Recloy10, in the exposure for the time up to 2000 h were negligibly small

231

Behaviour of corrosion product from irradiated stainless steel in flowing sodium  

International Nuclear Information System (INIS)

The behaviour of corrosion products in flowing sodium was analyzed. In particular: corrosion and leaching, deposition of radioactive products and radioactive sodium analysis. Corrosion products was obtained together with the corrosion rate of stainless steel specimens in flowing sodium

232

Stress corrosion cracking protection device  

International Nuclear Information System (INIS)

Purpose: To reduce dissolved oxygen at a reduced cost and simply thereby prevent stress corrosion cracking. Constitution: Taking notice of the fact that dissolved oxygen concentration is reduced in reactor water in contact with organic materials irradiated with radioactive rays such as ?-rays, organic materials such as polyethylenes are disposed to the inside of pipeways in reactor clean-up systems and radioactive rays are irradiated to them. Thus, reactor water can be brought into contact with organic materials, by which dissolved oxygen is caught by organic materials under the action of the radioactive rays to reduce the dissolved oxygen concentration. Further, if the organic materials are disposed to the inside of the pipeways connecting the heat exchanger and the desalter of the clean-up system, since the temperature of the reactor water is relatively low and the flow rate is not so high in this portion, dissolved oxygen can be removed stably and efficiently. (Kawakami, Y.)

233

Uniform corrosion monitoring of carbon steel in concrete  

Science.gov (United States)

Corrosion in concrete can cause disastrous destructions of bridges and other constructions. Different methods of corrosion monitoring can be applied including electrochemical noise despite its disadvantageous limitations. Noise measurements enable continuous monitoring of corrosive conditions inside concrete and recognition when corrosion starts to make trouble there. Results of electrochemical noise measurements in concrete are presented. Polarization resistance of carbon steel is estimated by current and voltage noise measurements. Changes of factor 2-4 of the estimated polarization resistance are recognized during time of noise registration. The observed changes in uniform corrosion rate can be identified by electrochemical noise analysis. Limitations of the applied method of polarization resistance evaluation are considered and presented.

Smulko, Janusz M.; Darowicki, Kazimierz; Zielinski, Artur

2004-05-01

234

Corrosion behavior of carbon steels under tuff repository environmental conditions  

International Nuclear Information System (INIS)

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. J-13 well water is representative of water which has percolated through the tuff horizon where the repository would be located. Tests were conducted in air-sparged J-13 water to attain stronger oxidizing conditions. 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 refs., 7 tabs

235

Fatigue of austenitic steels due to corrosion  

International Nuclear Information System (INIS)

In the context of the project 'Investigations of the influence of low cycle overloads in nuclear powerstation materials on the formation and propagation of cracks' supported by the Ministry of Research and Technology (1500860), low cycle fatigue tests were carried out in specially developed fatigue apparatus, supported by micro-computer. Flat samples (55 x 15 x 5 mm3, working crossection 10 x 3 mm2) and pipe samples (diameter 20 mm, wall thickness 5 mm, l=300 mm, working diameter thinned to 18 mm) made of Austenitic steel X6CrNiTi 18.10 were examined. In the fatigue tests on flat samples, the frequency (0.5, 5 and 25 Hz), the temperature (23 and 80 C), the surface properties (milled, polished, etched, passivated), the bending stress at the sample surface (225 and 280 MPa) and the corrosion conditions in a 0.01 m NaCl solution were potentiostatically varied. The tests were used to determine the causes and the main influential factors of the fatigue fracture of Austenitic steel. The results obtained from the flat samples were checked and expanded in the tests on pipe samples, with an expansion of the temperature range to 250 C and increased mechanical loading. Due to its high toughness, the Austenitic steel X6CrNiT 18.10 has a high resistance to fatigue fracture if the surface is free of defects. The cause for a fatigue fracture is the presence of surface defects, which act as stress concentrators. (orig./MM)M)

236

Corrosion Behavior of Mild Carbon Steel in Ethanolic Solutions  

Science.gov (United States)

Electrochemical evaluation of ASTM A36 steel was performed in ethanolic solutions containing small concentrations of water ranging from 0 to 10 vol.%. Electrochemical techniques such as open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization were utilized to analyze corrosion parameters. A fixed concentration of chloride, as per the ASTM specification for fuel grade ethanol, was added to increase the conductivity of the solutions. The effects of water and oxygen on the corrosion behavior of steel in these solutions have been discussed. Pitting corrosion of the steel specimens in these solutions was evaluated using scanning electron microscopy (SEM) and pitting analysis. This investigation was performed to establish a baseline for the microbiologically influenced corrosion (MIC) of steel in ethanolic solutions.

Bhola, Shaily M.; Bhola, Rahul; Jain, Luke; Mishra, Brajendra; Olson, David L.

2011-04-01

237

Controlled ferrite content improves weldability of corrosion-resistant steel  

Science.gov (United States)

Corrosion-resistant steel that adds restrictions on chemical composition to ensure sufficient ferrite content decreases the tendency of CRES to develop cracks during welding. The equations restricting composition are based on the Schaeffler constitution diagram.

Malin, C. O.

1967-01-01

238

Effect of segregation bands on corrosion of steel plate for ship hull  

Directory of Open Access Journals (Sweden)

Full Text Available Despite significant progress in the manufacturing of sheet metal ships carried both by optimizing the chemical compositions of steel mills as well as rolling and heat treatment, it still fails to remove the effects of persistent segregation. As a result we observed anisotropy of mechanical properties of the material which essentially complicates the process of construction for shipbuilding industry. Anisotropy of mechanical properties occurring in sheet metal hull is even more dangerous, that during their work, they are exposed to continuous exposure variable charges arising from sea surface waves. Another factor weakening the resistance to cracking metal ship is sea-water, which in the surface layer is highly aerated and very aggressive corrosion. The purpose of this study is to clarify the role of the segregation bands in the process of corrosion of low alloy steels used for ship hull. It was estimate a rate of corrosion in aerated sea water areas of the metal with or without segregation bands. After corrosion tests were made observations of specimens surfaces. Inside the segregation bands were found phosphorus. The contents of it were exceeded the average this element content in the steel. At the same time areas of the sheet metal with segregation bands were slowly corroded than areas without bands, although the changes of corrosion rate was similar in nature.Corrosion activity of rich in phosphorus segregation band is similar to phosphate corrosion inhibitors. These are effective in the presenceof chloride in seawater to form a protective layer that protects against corrosion segregation band. Under the observation on scanningelectron microscope there was no change in the appearance of surface samples after corrosion tests. A future direction of research will be estimate the stress corrosion in the same species – with and without segregation bands.

M. Mazur

2010-07-01

239

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

240

Corrosion and potentiostatic hydrogenation of carbon steels in carbonate and sulfide solutions  

International Nuclear Information System (INIS)

Corrosion behaviour and hydrogenation of two structural carbon steel at controlled potentials in the interval of -1.4 V-+0.4 V in a carbonate-bicarbonate solution (pH 9.4) on the free oxygen access, solution deaeration with argon and saturation with hydrogen sulfide (pH 8.5) are studied. It is established that in the deaerated solution on the potential cathode shift is realized the steel cathode protection where as in carbonate-sulfide solution is found increasing the corrosion rate. 6 refs., 3 figs

 
 
 
 
241

Temperature and time effects on the acid corrosion of steel in the presence of acetylenic inhibitors  

International Nuclear Information System (INIS)

One studied the influence of temperature and time dependent polymer film formation speed on kinetics of iron electrode processes and on rate of soft steel corrosion. High inhibiting effect of propargyl alcohol (PA) and of propargylchloride (PC) on electrode processes and on corrosion of steel in hydrochloric acid and that of PC in sulfuric acid is shown to increase with time and temperature increase and to be resulted from formation of polymer phase film on a metal. Loss of protective effect of PA in sulfuric acid results from its cathode hydrogenation and desorption of hydrogenation products

242

Corrosion of alloy steels in oil field fluids  

Energy Technology Data Exchange (ETDEWEB)

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.

Martin, R.L.

1987-01-01

243

Corrosion of alloy steels in oil field fluids  

International Nuclear Information System (INIS)

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

244

On the use of triazines as inhibitors of steel corrosion  

International Nuclear Information System (INIS)

A possibility of using substandard pesticides as a raw materials for synthesis of a set of triazines and also using them as a inhibitors of acidic corrosion of steel 20, as well as additions to epoxy powder coatings is considered. It is shown that triazines studied are inhibitors of acidic corrosion of steel 20. 2,4-di(ethylamino)-6-phenylhydrazono-1,3,5-triazine (In 4) has a maximum inhibiting effect among the studied compounds

245

AFM study of steel corrosion in aqueous solutions in concrete  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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,...

Di?az-benito, B.; Velasco, F.; Guzma?n, S.; Calabre?s, R.

2011-01-01

246

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

247

Silane coupling agents for corrosion protection  

Science.gov (United States)

Organofunctional silanes have retained special attention of the adhesion world for a long time. The current work attempts to expand the areas of application of silanes into corrosion control of metals and alloys. Studies of selected functional and non-functional silane films formed on iron substrates showed that there is interaction between the amine functional group of gamma-aminopropyl trimethoxysilane (gamma-APS) and the iron substrate, the result of which is no improvement in corrosion protection. A non-functional silane, Bis-triethoxysilyl ethane (BTSE), on the other hand, formed more number of oxane bonds with the substrate, when applied from acidic pH range. This results in improved corrosion protection. A two-step silane treatment consisting of a non-functional first silane layer and a functional silane second layer is proposed, which can provide corrosion protection and adhesion enhancement. Several alloy systems and bis-silanes are investigated and the two step silane treatment is shown to improve both adhesion and corrosion performance. The selection of the silane application pH is shown to be related to the stability of the metal or oxide surface present. The roles of the first and second layer of the silane are corrosion protection and adhesion improvement with the top-coat respectively. Concentration of BTSE in the coating solution is shown to affect the properties of the protective film formed on AL 2024. The thickness of the silane film increases proportional to the concentration. Thinner films of BTSE reduce only the cathodic reaction rates at the metal surface, whereas thicker films substantially reduce both anodic and cathodic reaction rates. These results also match several performance tests including ASTM B-117 salt spray. On Al 1050, the oxide layer on the surface is shown to have little effect on the electrical properties of the BTSE film formed. Preheating the surface and curing of the deposited film strongly influence the electrical properties. The condensation reaction occurring during the curing process results in a hydrophobic silane film. This results in the emergence of a second relaxation in the impedance behavior, which is directly related to the resistance offered by the silane film towards corrosive attack.

Subramanian, Vijay

2000-10-01

248

Corrosion protection for silver reflectors  

International Nuclear Information System (INIS)

This patent describes a method of protecting a silver reflector from damage caused by contact with gaseous substances. It comprises: at least partially coating the reflector to a thickness of 15 Angstrom or less with a substance selected from a group containing aluminum oxide, magnesium oxide, titanium dioxide, silicon dioxide, yttrium oxide, hafnium oxide, zirconium oxide, and praseodymium oxide

249

Electrochemical methods for characterisation of thermal spray corrosion resistant stainless steel coatings  

International Nuclear Information System (INIS)

The use of thermal spray stainless steel coatings for protection of low alloyed steels against different types of corrosion is limited due to high porosity levels and oxide inclusions. In this paper electrochemical methods like corrosion potential monitoring and cyclic voltammetry are reported to monitor the corrosion resistance of thermal spray coatings. The studied stainless steel AISI 316 coatings are deposited by arc spraying, plasma spraying or high velocity oxygen fuel (HVOF) spraying. The electrochemical tests are performed in a 0.5 M H2SO4 solution. It is found that none of the tested coatings had an electrochemical response equal to that of stainless steel alloy AISI 316. The results indicate that the HVOF coating has the highest corrosion resistance and the corrosion resistance of arc spray coatings can be improved by spraying in an inert argon atmosphere. The electrochemical response of the studied arc spray coatings is independent of substrate type (including the case of no substrate), indicating that the underlying alloy does not contribute to the corrosion process and only the coating itself is attacked. The HVOF coatings age rapidly in a 0.5 M H2SO4 solution. It is proposed that this is due to pore opening and pore widening. (orig.)

250

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

International Nuclear Information System (INIS)

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

251

The Effect of Sour Gases and Some Anions on the Corrosion Behavior of Carbon Steel  

Scientific Electronic Library Online (English)

Full Text Available SciELO Portugal | Language: English Abstract in english The effect of the presence of CO2 and H2S in the well water used in the petroleum plant on corrosion of carbon steel has been tested using impedance measurements. Carbon dioxide leads to decrease in the resistivity of the film developed on the metallic surface, while the effect of hydrogen sulfide i [...] s less pronounced. Scanning electron micrographs have shown that corrosion products cover only small part of metallic surface in water containing CO2. Studies under polarization conditions will allow concluding that the dissolved gases in the well water reduce the ability of the film to protect the metal against corrosion. The influence of the oxoanions and halide ions on the corrosion rate of steel has also been analyzed.

S.A., Salih; A.A., Mazhar; H., Mahanny.

252

Influence of sulphur content, sulphur distribution and deoxidation practice on the corrosion of steel in seawater  

International Nuclear Information System (INIS)

Seven steels, mainly differing by the sulphur content have been exposed for two years in the splash water-, alternate immersion-, and continuous immersion zones of the test stand Helgoland of the Verein Deutscher Eisenhuettenleute. High sulphur contents led in the splash water zone to a markedly higher corrosion attack. This is attributable to the formation of sulphate clusters, reducing the protective effect of formed rust layers. In addition, the sulphur content influences to a slight extent also the formation of the surface layers in the alternate immersion zone. In the continuous immersion zone, there is no evidence of any influence of the sulphur on corrosion. The deoxidation practice and the distribution of the sulphur had no bearing on the corrosion rates. A localy increased corrosion attack, being in a causal connection with the sulphides in the steel, was not observed. (orig./RW)

253

The Effect of Sour Gases and Some Anions on the Corrosion Behavior of Carbon Steel  

Directory of Open Access Journals (Sweden)

Full Text Available The effect of the presence of CO2 and H2S in the well water used in the petroleum plant on corrosion of carbon steel has been tested using impedance measurements. Carbon dioxide leads to decrease in the resistivity of the film developed on the metallic surface, while the effect of hydrogen sulfide is less pronounced. Scanning electron micrographs have shown that corrosion products cover only small part of metallic surface in water containing CO2. Studies under polarization conditions will allow concluding that the dissolved gases in the well water reduce the ability of the film to protect the metal against corrosion. The influence of the oxoanions and halide ions on the corrosion rate of steel has also been analyzed.

S.A. Salih

2004-01-01

254

Corrosion behaviour and biocorrosion of galvanized steel water distribution systems.  

Science.gov (United States)

Galvanized steel tubes are a popular mean for water distribution systems but suffer from corrosion despite their zinc or zinc alloy coatings. First, the quality of hot-dip galvanized (HDG) coatings was studied. Their microstructure, defects, and common types of corrosion were observed. It was shown that many manufactured tubes do not reach European standard (NBN EN 10240), which is the cause of several corrosion problems. The average thickness of zinc layer was found at 41?m against 55?m prescribed by the European standard. However, lack of quality, together with the usual corrosion types known for HDG steel tubes was not sufficient to explain the high corrosion rate (reaching 20?m per year versus 10?m/y for common corrosion types). Electrochemical tests were also performed to understand the corrosion behaviours occurring in galvanized steel tubes. Results have shown that the limiting step was oxygen diffusion, favouring the growth of anaerobic bacteria in steel tubes. EDS analysis was carried out on corroded coatings and has shown the presence of sulphur inside deposits, suggesting the likely bacterial activity. Therefore biocorrosion effects have been investigated. Actually sulphate reducing bacteria (SRB) can reduce sulphate contained in water to hydrogen sulphide (H2S), causing the formation of metal sulphides. Although microbial corrosion is well-known in sea water, it is less investigated in supply water. Thus, an experimental water main was kept in operation for 6months. SRB were detected by BART tests in the test water main. PMID:24503139

Delaunois, F; Tosar, F; Vitry, V

2014-06-01

255

Inhibition of steel corrosion by electrosynthesized poly(o-anisidine)-dodecylbenzenesulfonate coatings  

Energy Technology Data Exchange (ETDEWEB)

Poly(o-anisidine)-dodecylbenzenesulfonate (POA-DBSA) coatings were synthesized on stainless steel from aqueous solution containing o-anisidine and dodecylbenzene sulfonic acid by using cyclic voltammetry. These coatings were characterized by Fourier transform infrared spectroscopy (FTIR), UV-vis absorption spectroscopy, scanning electron microscopy (SEM) and cyclic voltammetry (CV). Corrosion tests of these coatings were carried out in aqueous 3% NaCl solution by using open circuit potential (OCP) measurements, potentiodynamic polarization technique, cyclic potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS). The results reveal that POA-DBSA acts as a corrosion protective coating on steel and reduces the corrosion rate (CR) of steel almost by a factor of 14.5.

Chaudhari, Sudeshna, E-mail: sudeshna6480@yahoo.co.i [Department of Physics, North Maharashtra University, Jalgaon 425001, Maharashtra (India); Patil, P.P. [Department of Physics, North Maharashtra University, Jalgaon 425001, Maharashtra (India)

2010-09-01

256

Inhibition of steel corrosion by electrosynthesized poly(o-anisidine)-dodecylbenzenesulfonate coatings  

International Nuclear Information System (INIS)

Poly(o-anisidine)-dodecylbenzenesulfonate (POA-DBSA) coatings were synthesized on stainless steel from aqueous solution containing o-anisidine and dodecylbenzene sulfonic acid by using cyclic voltammetry. These coatings were characterized by Fourier transform infrared spectroscopy (FTIR), UV-vis absorption spectroscopy, scanning electron microscopy (SEM) and cyclic voltammetry (CV). Corrosion tests of these coatings were carried out in aqueous 3% NaCl solution by using open circuit potential (OCP) measurements, potentiodynamic polarization technique, cyclic potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS). The results reveal that POA-DBSA acts as a corrosion protective coating on steel and reduces the corrosion rate (CR) of steel almost by a factor of 14.5.

257

Localised corrosion processes of austenitic stainless steel bipolar plates for polymer electrolyte membrane fuel cells  

Energy Technology Data Exchange (ETDEWEB)

This research addresses the problem of localised corrosion of stainless steel PEMFC bipolar plates. The susceptibility to pitting and crevice corrosion of austenitic AISI 304 stainless steel has been investigated both by post-mortem microscopic analysis of the end-plates of a laboratory single-cell and by studies of electrochemically corroded stainless steels, in the presence of specially-designed crevice-formers simulating the operating conditions of a PEMFC. This work is based on optical and scanning-electron microscopies as well as potentiostatic and potentiodynamic measurements. The crevice-formers we considered were: Teflon, graphite and AISI 304. The samples, coupled to the crevice-formers have been tested in aqueous solutions containing Cl{sup -}, SO{sub 4}{sup 2-} and F{sup -}. From the E-log i plot, the values of corrosion, pitting, crevice and protection potential have been obtained and perfect and imperfect passivity conditions have been identified. (author)

Mele, Claudio; Bozzini, Benedetto [Dipartimento di Ingegneria dell' Innovazione, Universita del Salento, via Monteroni, 73100 Lecce (Italy)

2010-06-01

258

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

International Nuclear Information System (INIS)

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.)

259

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

Science.gov (United States)

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.

Mohamed, Nedal; Boulfiza, Mohamed; Evitts, Richard

2013-03-01

260

Analysis of corrosion data for carbon steels in simulated salt repository brines and acid chloride solutions at high temperatures  

International Nuclear Information System (INIS)

Carbon steel is currently the leading candidate material for fabrication of a container for isolation of high level nuclear waste in a salt repository. Since brine entrapped in the bedded salt can migrate to the container by several transport processes, corrosion is an important consideration in the long-term performance of the waste package. A detailed literature search was performed to compile relevant corrosion data for carbon steels in anoxic acid chloride solutions, and simulated salt repository brines at temperatures between ? 20 and 4000C. The hydrolysis of Mg2+ ions in simulated repository brines containing high magnesium concentrations causes acidification at temperatures above 250C, which, in turn, influences the protective nature of the magnetite corrosion product layer on carbon steel. The corrosion data for the steels were analyzed, and an analytical model for general corrosion was developed to calculate the amount of penetration (i.e., wall thinning) as a function of time, temperature, and the pressure of corrosion product hydrogen than can build up during exposure in a closed system (e.g., a sealed capsule). Both the temperature and pressure dependence of the corrosion rate of steels in anoxic acid chloride solutions indicate that the rate-controlling partial reaction is the cathodic reduction of water to form hydrogen. Variations in the composition and microstructure of the steels or the concentration of the ionic species in the chloride solutions (provided that they do not change the pH significantly) do not appear to strongly influence the corrosion rate

 
 
 
 
261

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

Directory of Open Access Journals (Sweden)

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.

Elkais Ali Ramadan

2011-01-01

262

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

Science.gov (United States)

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.

Sahri, M. I.; Othman, N. K.; Samsu, Z.; Daud, A. R.

2014-09-01

263

Corrosion of reinforcing steel in concrete - electrochemical laboratory experiments  

International Nuclear Information System (INIS)

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

264

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

International Nuclear Information System (INIS)

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

265

Efficiency of Corrosion Inhibitors on Cathodic Protection System  

Directory of Open Access Journals (Sweden)

Full Text Available This study is on experiment being carried out to determine the efficiency of in inhibitors on catholically protected medium carbon steel in sea water in Bonny and Ogbokoro in the Niger Delta region of Nigeria. The experiment was conducted using the total immersion technique in a non-flowing media containing sea water inhibited with potassium dichromate, sodium nitrate, ECIO21A, sarvor CK 368, and Kurizets 636. In the course of this research work, Cathodically protected and unprotected medium carbon steel were totally immersed in seawater containing the aforementioned inhibitors differently. Their weight loss, corrosion rate, pH value and corrosion potentials were determined at intervals of 72 hours, over 2016 hours the test lasted. The results obtained shows that inhibitor EC1021A has efficiency of 79.8%, other results are as follows: Kurizet S.636, 77%, savor CK368, 43%, potassium dichromate, 35% and sodium nitrate, 1.88%. It was concluded that EC1021A is the most efficient inhibitor, under a non-flow system.

Tobinson Briggs

2014-02-01

266

Flow accelerated corrosion and erosion-corrosion of RAFM steel in liquid breeders  

Energy Technology Data Exchange (ETDEWEB)

Corrosion experiments for RAFM, JLF-1 steel (Fe-9Cr-2W-0.1C) in three types of liquid breeders (i.e. Li, Pb-17Li and Flinak) were performed at 600 {sup o}C. The influence of the different experimental parameters, such as a flowing condition, an exposure time and a geometric condition, on the corrosion behavior was investigated. The present study focused on the evaluation of the weight loss of the corroded specimen by the corrosion model based on mass transfer. The dissolution of the metal elements from the steel was accelerated by the fluids. An erosion-corrosion of the steel was caused by the peeling off of the corroded steel surface in the flowing liquid breeders.

Kondo, Masatoshi, E-mail: kondo.masatoshi@nifs.ac.jp [National Institute for Fusion Science, Toki (Japan); Muroga, Takeo; Sagara, Akio [National Institute for Fusion Science, Toki (Japan); Valentyn, Tsisar [Physico-Mechanical Institute of National Academy of Sciences of Ukraine, Lviv (Ukraine); Suzuki, Akihiro; Terai, Takayuki [University of Tokyo, Tokyo (Japan); Takahashi, Minoru [Tokyo Institute of Technology, Tokyo (Japan); Fujii, Naoki [Biko chemical company, Kobe, 658-0013 (Japan); Yokoyama, Yukihiro; Miyamoto, Hiroshi; Nakamura, Eiji [Santoku cooperation, Kobe, 673-0443 (Japan)

2011-10-15

267

Flow accelerated corrosion and erosion-corrosion of RAFM steel in liquid breeders  

International Nuclear Information System (INIS)

Corrosion experiments for RAFM, JLF-1 steel (Fe-9Cr-2W-0.1C) in three types of liquid breeders (i.e. Li, Pb-17Li and Flinak) were performed at 600 oC. The influence of the different experimental parameters, such as a flowing condition, an exposure time and a geometric condition, on the corrosion behavior was investigated. The present study focused on the evaluation of the weight loss of the corroded specimen by the corrosion model based on mass transfer. The dissolution of the metal elements from the steel was accelerated by the fluids. An erosion-corrosion of the steel was caused by the peeling off of the corroded steel surface in the flowing liquid breeders.

268

Corrosion of steel in simulated nuclear waste solutions  

International Nuclear Information System (INIS)

Processing of inhibited nuclear waste to forms for long-term storage will cause waste tank environments to have dynamic conditions. During processing compositional changes in the waste may produce a corrosive environment for the plain carbon steel tanks. Large concentrations of nitrates which corrode steel are contained in the waste. Nitrite and hydroxides are added to inhibit any corrosion. Concentration changes of nitrate and nitrite were investigated to identify corrosion regimes that may occur during processing. Corrosion testing was performed with cyclic potentiodynamic polarization and linear polarization resistance. Test samples were plain carbon steel which was similar to the material of construction of the waste tanks. The corrosion morphology of test samples was investigated by visual evaluation and scanning electron microscopy. Qualitative chemical analysis was also performed using energy dispersive spectroscopy. The corrosion mechanism changed as a function of the nitrate concentration. As the nitrate concentration was increased the steel transitioned from a passive state to general attack, and finally pitting and crevice corrosion. The nitrate anion appeared to destabilize the surface oxide. Nitrite countered the oxide breakdown, although the exact mechanism was not determined

269

Evaluation of the corrosion resistance of different galvanized steels treated in a cerium salt solution  

Energy Technology Data Exchange (ETDEWEB)

Analysis of polarization curves and impedance spectra has shown that the surface chemistry of galvanized steels plays an important role in determining their corrosion behavior. Zn-Ni samples that were untreated or had been treated in a 10 mM Ce(NO{sub 3}){sub 3} solution had the lowest corrosion rates in 0.5 N NaCl. The efficiency of the surface modification process was the highest for electrogalvanized steel. Surface analysis showed that the protective layers on Zn-Ni and electrogalvanized steel contained mainly cerium oxides/hydroxides, while the layer on hot-dipped steel consisted mainly of zinc hydroxide. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

Song, Y.K.; Mansfeld, F. [Corrosion and Environmental Effects Laboratory (CEEL), Department of Materials Science and Engineering, University of Southern California, Los Angeles, CA 90089-0241 (United States)

2005-04-01

270

Peroxy molybdates preparation, characterization and mild steel corrosion inhibition  

International Nuclear Information System (INIS)

Six peroxyl molybdates were prepared by varying pH (5,6 and 7) and ratio between hydrogen peroxide and molybdate (2:1 and 1:1). These were characterized as mono-, di-mixed and polymerized peroxy molybdates. The best corrosion inhibition of mild steel in simulated cooling water (SCW) was obtained by di peroxy molybdate. This shows the beneficial effect of per oxo group addition to molybdate. Other peroxy molybdates did not show improved corrosion inhibition compared to the molybdate. This was due to decomposition of these peroxy molybdates before reaching the mild steel surface. With citric acid, peroxy molybdates provided highly improved corrosion inhibition of mild steel in SCW and the result was obtained with monomeric mono peroxy molybdates. These results as well as the mechanisms of corrosion inhibition were discussed. (author)

271

Corrosion protection of the annular water container of the Rheinsberg AKW1 reactor  

International Nuclear Information System (INIS)

The difficult accessible annular water container of the PWR, made from low-alloyed steel 16 Mn 3, was protected against corrosion by the combination consisting of a coating system (200 to 300 ?m thick sprayed aluminium layer + 4 layers of bituminous lacquer) and inhibition of the water used (deionized) by magnesium or potassium chromate. After twenty years of service no remarkable corrosion attack was found. (author)

272

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

International Nuclear Information System (INIS)

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.

273

Desenvolvimento e uso do compósito de Nb2O5|Cu como revestimento aplicado por aspersão térmica sobre o aço AISI 1020 para proteção contra a corrosão pelo solo em estruturas enterradas Development of Nb2O5|Cu composite as AISI 1020 steel thermal spray coating for protection against corrosion by soil in buried structures  

Directory of Open Access Journals (Sweden)

Full Text Available 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.

Oscar Regis Junior

2012-01-01

274

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  

Energy Technology Data Exchange (ETDEWEB)

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)

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

275

Desenvolvimento e uso do compósito de Nb2O5|Cu como revestimento aplicado por aspersão térmica sobre o aço AISI 1020 para proteção contra a corrosão pelo solo em estruturas enterradas / Development of Nb2O5|Cu composite as AISI 1020 steel thermal spray coating for protection against corrosion by soil in buried structures  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese [...] Abstract in english 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 coatin [...] gs 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.

Oscar, Regis Junior; José Maurílio da, Silva; Kleber Franke, Portella; Ramon Sigifredo Cortes, Paredes.

276

Desenvolvimento e uso do compósito de Nb2O5|Cu como revestimento aplicado por aspersão térmica sobre o aço AISI 1020 para proteção contra a corrosão pelo solo em estruturas enterradas / Development of Nb2O5|Cu composite as AISI 1020 steel thermal spray coating for protection against corrosion by soil in buried structures  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese [...] Abstract in english 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 coatin [...] gs 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.

Oscar, Regis Junior; José Maurílio da, Silva; Kleber Franke, Portella; Ramon Sigifredo Cortes, Paredes.

1517-15-01

277

Corrosion fatigue of a superduplex stainless steel weldment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Comer, Anthony John

2004-01-01

278

Corrosion of carbon steel nuclear waste containers in marine sediment  

International Nuclear Information System (INIS)

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)

279

PITTING CORROSION OF STAINLESS STEEL AT THE VARIOUS SURFACE TREATMENT  

Directory of Open Access Journals (Sweden)

Full Text Available The stainless steel surface treatment is very important with regard to its pitting corrosion susceptibility. An effect of various types surfacing on pitting corrosion resistance of AISI 304stainless steel is investigated in this work. The samples of the tested material are turned, blasted, peened, grinded and a half of them are pickled to achieve higher purity of surfaces and better quality of passive film. Eight types of different finished surfaces are tested by electrochemical and immersion tests to determine corrosion behaviour in conditions where pitting is evoked by controlled potential and second by solution with high redox potential. By this way the effect of mechanical and chemical surface treatment on the resistance to pitting corrosion, character, size and shape of pits are compared in the conditions of different mechanisms of corrosion process.

Viera Zatkalíková

2012-02-01

280

PITTING CORROSION OF STAINLESS STEEL AT THE VARIOUS SURFACE TREATMENT  

Directory of Open Access Journals (Sweden)

Full Text Available The stainless steel surface treatment is very important with regard to its pitting corrosion susceptibility. An effect of various types surfacing on pitting corrosion resistance of AISI 304stainless steel is investigated in this work. The samples of the tested material are turned, blasted, peened, grinded and a half of them are pickled to achieve higher purity of surfaces and better quality of passive film. Eight types of different finished surfaces are tested by electrochemical and immersion tests to determine corrosion behaviour in conditions where pitting is evoked by controlled potential and second by solution with high redox potential. By this way the effect of mechanical and chemical surface treatment on the resistance to pitting corrosion, character, size and shape of pits are compared in the conditions of different mechanisms of corrosion process.

Viera Zatkalíková

2011-09-01

 
 
 
 
281

Polyethyleneimine as a corrosion inhibitor for ASTM 420 stainless steel in near-neutral saline media  

International Nuclear Information System (INIS)

The effect of polyethyleneimine (PEI) as a corrosion inhibitor for ASTM 420 stainless steel in 3% aqueous NaCl solution was studied. The results of linear polarization and cyclic polarization measurements indicate high inhibiting effectiveness of the selected organics. Moreover, from cyclic polarization measurements it can be deduced that PEI acts as an inhibitor against pitting corrosion. Immersion tests in the presence of PEI showed remarkable corrosion protection against uniform corrosion. Film persistency immersion testing indicated that once the protective layer is formed, it is very stable in a non-inhibited NaCl solution. X-ray photoelectron spectroscopy measurements showed that PEI binding is mediated by electrostatic interactions between PEI and the substrate. A dense layer of PEI might be effective either in preventing diffusion of ionic species from the film or in preventing attack by chlorine from the salt water

282

Crevice corrosion resistivity assessment of carbon steel and stainless alloys  

International Nuclear Information System (INIS)

The disposal facility for radioactive wastes requires long-term integrity. Metal is considering to use as the engineered barrier which constructs the outer walls in such facility, in order to prevent groundwater from percolating into such disposal facility. The present report discusses crevice corrosion resistivity assessment of carbon steel and stainless alloys. Potential-pH (E-pH) diagram for carbon steel is obtained in the environment of water which imitates groundwater in Japan. And the repassivation potential for crevice corrosion, ER,CREV, is measured by an electro-chemical test. And natural corrosion potential, ESP, and ER,CREV for stainless alloys. Type 304 steel and Titanium alloys (ASTM Gr. 1-Ti, Gr, 12-Ti), are measured in the environment of neutral and alkalized water. And usable condition of these materials are discussed. The conclusion of this paper are: 1) In the environment of higher values of pH, carbon steel is in the state of passivation. In this state it can occur crevice corrosion, at least in the condition of [Cl-]? 10ppm. So, using carbon steel is inadequate for coexistence with concrete lining which shows higher pH environment. In neutral pH environment which without concrete, carbon steel is in the state of uniform corrosion, and can be used by previous consideration of diminishing its thickness by corrosion. 2) Usable diagram for crevice corrosion of stainless alloys is obtained, which includes [Cl-] concentration and temperature as a parameter. And it can be said that the adequate selection of materials by using this diagram can assure long-term integrity for groundwater corrosion. (author)

283

Water corrosion resistance of ODS ferritic-martensitic steel tubes  

International Nuclear Information System (INIS)

Oxide dispersion strengthened (ODS) ferritic-martensitic steels have superior radiation resistance; it is possible to achieve a service temperature of up to around 973 K because of their superior creep strength. These advantages of ODS steels facilities their application to long-life cladding tubes in advanced fast reactor fuel elements. In addition to neutron radiation resistance, sufficient general corrosion resistance to maintain the strength of the cladding, and the stress corrosion cracking (SCC) resistance for spent-fuel-pool cooling systems and high-temperature oxidation for the fuel-clad chemical interaction (FCCI) of ODS ferritic steel are required. Although the addition of Cr to ODS is effective in preventing water corrosion and high-temperature oxidation, an excessively high amount of Cr leads to embrittlement due to the formation of a Cr-rich ?' precipitate. The Cr content in 9Cr-ODS martensite and 12Cr-ODS ferrite, the ODS steels developed by the Japan Atomic Energy Agency (JAEA), is controlled. In a previous paper, it has been demonstrated that the resistances of 9Cr- and 12Cr-ODS ferritic-martensitic steels for high-temperature oxidation are superior to those of conventional 12Cr ferritic steel. However, the water corrosion data of ODS ferritic-martensitic steels are very limited. In this study, a water corrosion test was conducted on ODS steels in consideration of the spent-fuel-pool cooling condition, and the results were compared with those of converesults were compared with those of conventional austenitic stainless steel and ferritic-martensitic stainless steel. (author)

284

Study of steel corrosion by application of neutron activation analysis  

International Nuclear Information System (INIS)

In studies of the corrosion process of structural materials to be used in chemical industry neutron instrumental activation analysis was applied. Steel specimens were irradiated in a WWR-S reactor for 80 hours at a neutron flux of 2 x 1017 nm-2s-1. Cooling time before starting corrosion experiments was one month. The corrosion tests were performed according to a Czechoslovak Standard. The experiments gave evidence of a disproportionate dissolution in the initial stage of corrosion. Though a steady state is characteristic of the following stage, in many cases the disproportion in solubility continues. (author)

285

76 FR 77775 - Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Extension of Time...  

Science.gov (United States)

...Trade Administration [C-580-818] Corrosion-Resistant Carbon Steel Flat Products...review of the countervailing duty order on corrosion-resistant carbon steel flat products...2009, through December 31, 2009. See Corrosion-Resistant Carbon Steel Flat...

2011-12-14

286

77 FR 13093 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Final Results of...  

Science.gov (United States)

...Trade Administration [C-580-818] Corrosion-Resistant Carbon Steel Flat Products...countervailing duty (``CVD'') order on corrosion-resistant carbon steel flat products...1\\ See Corrosion-Resistant Carbon Steel Flat...

2012-03-05

287

78 FR 19210 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Final Results of...  

Science.gov (United States)

...C-580-818] Corrosion-Resistant Carbon Steel Flat Products From the Republic...order on corrosion-resistant carbon steel flat products from the Republic...1\\ See Corrosion-Resistant Carbon Steel Flat Products From the...

2013-03-29

288

Investigation of Fecraly Coating on Corrosion Behaviour of Mild Steel  

Directory of Open Access Journals (Sweden)

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.

Joseph B. AGBOOLA

2009-07-01

289

A Study on Corrosion Resistance of Coating System on Steel  

International Nuclear Information System (INIS)

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

290

The electrochemical corrosion of maraging steel in various media  

International Nuclear Information System (INIS)

Electrochemical corrosion behavior of maraging steel in various media has been studied using electrode kinetic measurements. The media used included IN H/sub 2/SO/sub 4/, IN HCl and artificial sea water, all at room temperature. The steel used was 350 grade of maraging steel and its corrosion behavior was studied in annealed as well as aged condition. In addition to the general behavior observed using potentiodynamic polarization, the corrosion rates were also evaluated using our own method known as ZTCorr. This method has been proved to be robust and accurate as compared to any other known method. The surfaces of corroded specimens were examined in an scanning electron microscope. The pitting observed in samples corroded by sea water was found to be associated with the inclusion present in the steel. Passive behavior was noted in IN H/sub 2/SO/sub 4/ but not IN HCl or artificial sea water. (author)

291

Investigation of sodium phenylanthranilate as an inhibitor of steel corrosion in neutral media  

International Nuclear Information System (INIS)

Effect of sodium phenylanthranilate (SPhN) on corrosion and electrochemical behaviour of armco- and Kh18N10T steels is studied in borate buffer solutions (pH=7.36) and in water. It is established that protective effect on Kh18N10T steels is higher, that is connected with the increased chromium content. Presence of F and CH3COO- ions in studied solutions does not cause the pitting of armco and Kh18N10T steels. It is proposed to use SPhN as a practically safe inhibitor

292

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Mehanna, Maha; Basse?guy, Re?gine; De?lia, Marie-line; Bergel, Alain

2009-01-01

293

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  

International Nuclear Information System (INIS)

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.

294

Mechanisms of corrosion and denting of ferritic steels in aqueous chloride at 3000C  

International Nuclear Information System (INIS)

An investigation of aqueous corrosion of 0-23% Cr ferritic steels and binary alloys has been carried out in pure water, NiCl2 solutions, and mixtures of FeCl2 or CuCl2 with NiCl2 and seawater at 3000C. The main series of tests on Cr containing alloys was in a standard solution of 0.1 M NiCl2 for up to 1200 h. Low (1 - 2%) Cr alloys showed initially protective, duplex oxide growth. Subsequently lamination of the inner spinel layer occurred, with the onset of linear corrosion rates which were slower than those of carbon steel. For higher %Cr steels in the standard solution, corrosion rates are approximately two orders of magnitude less than for carbon steel. The oxides were duplex with an inner iron/chromium spinel layer of equal volume to the metal consumed, surmounted by an outer layer of solution deposited magnetite. Oxide morphologies and growth mechanisms are discussed and the implications for PWR steam generator corrosion are analyzed. Recommendations are proposed for maximum seawater levels in steam generator bulk water to avoid long term corrosion damage

295

Corrosion behaviour of AISI 304 stainless steel with Cu coatings in H2SO4  

International Nuclear Information System (INIS)

The work addresses the influence of cementation and electrodeposition of copper coatings on the corrosion resistance of AISI 304 stainless steel immersed in 30 wt.% H2SO4 at temperatures of 25 and 50 deg. C. Corrosion process was evaluated by gravimetric tests, DC measurements and electrochemical impedance spectroscopy (EIS). The specimen surfaces were analysed by scanning electron microscopy, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction. The corrosion performance of AISI 304 stainless steel in sulphuric acid solution was greatly improved by copper coatings. The amount of copper deposited by the cementation process was sufficient to protect the stainless steel of corrosion. A greater amount of copper obtained by electrodeposition treatments does not supply further improvement in the corrosion behaviour. The improved corrosion resistance is related to copper dissolution at the initial stages of immersion tests and the presence of Cu2+ in the solution, which makes the medium more oxidizing, increasing the stability of the passive layer. In addition, the presence of copper at the surface reduces the overpotential of cathodic reaction, enabling the transition from an active region to the passive one

296

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

International Nuclear Information System (INIS)

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)

297

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

International Nuclear Information System (INIS)

Corrosion tests were carried out on austenitic AISI 316L and 1.4970 steels 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. After 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

298

Effect of long-term aging on electrochemical corrosive behavior of 17-4PH stainless steel  

International Nuclear Information System (INIS)

The corrosion and electrochemical behavior of long-term aging on 17-4PH stainless steel in different solutions has been measured by electrochemical methods. The solutions consisted of chlorine ion sulphuric acid and neutral. Electrochemical potential dynamic reactivation test. The polarization curves results demonstrate that the pitting potential of 17-4PH stainless steel shifted negatively and the protection performance of the passive film decreased after aging treatment. The decline of corrosion resistance of aged specimens ,and with the age time prolonging corrosion inhibitors is decline the sulphuric acid can control the pit corrosion of 17-4PH stainless steel because the vitriol (S) can hold back the Cl-, The anodic polarization curves illustrate that 17-4PH stainless steel can passive in 1% NaCl sulphuric acid, while in 1% NaCl neutral the passivity is deteriorated due to Cl- ion participate in electrochemical corrosion, accelerate the localized corrosion, destroy passivation and induce pit corrosion to the stainless steel. The decline of corrosion resistance of aged specimens was due to the precipitation of the second phase along grain boundaries and the transformation of microstructure. (authors)

299

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

International Nuclear Information System (INIS)

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

300

Corrosion and erosion-corrosion behaviors of carbon steel in naphthenic acid media  

International Nuclear Information System (INIS)

The naphthenic acid corrosion (NAC) and erosion-corrosion (NAEC) behaviors of carbon steel were investigated detailedly in laboratory. The resistance to NAEC of pack-aluminized carbon steel and carbon steel coated by high velocity oxygen-fuel (HVOF) thermal-sprayed AISI 316L stainless steel, was also investigated in both laboratory and an oil refinery. It was found that the control-step of NAC was primarily dependent on the temperature. The NAC rate of carbon steel increased markedly with the increase of the total acid number and temperature, which may be attributed to the enhanced absorption and active reaction of naphthenic acid molecules on the metal surface. Increasing the velocity of flow seriously aggravated NAEC, especially in the high temperature range. The reasons were closely associated with the enhanced mass transfer and the accelerated active reaction as well as the rapid spallation of corrosion products from the metal surface. Both the aluminized carbon steel and the carbon steel covered by HVOF coating showed better resistance against NAEC compared to the carbon steel due to higher microhardness and corrosion resistance of their surface-layers. The HVOF coating is hopeful to be applied for NAEC prevention of the components in oil refineries in view of present experimental results. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

 
 
 
 
301

Stress corrosion cracking of stainless steel used in drill collars  

International Nuclear Information System (INIS)

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

302

Correlation between composition of passive layer and corrosion behavior of high Si-containing austenitic stainless steels in nitric acid  

Science.gov (United States)

Austenitic stainless steels with 18% Cr have a good corrosion behavior in pure nitric acid. However, when oxidizing power of the solution increases, this kind of stainless steels faces a severe intergranular corrosion. Adding a sufficiently high concentration of silicon to the steel avoids this type of corrosion: in oxidizing solutions, those stainless steels exhibit generalized corrosion but their dissolution rate is higher than the one of stainless steels without silicon. To find out the role of silicon on such effects, the corrosion behavior of two different stainless steels with equivalent chromium content but with different silicon content (304L steel and Uranus S1N) has been studied in concentrated nitric acid solutions. Correlations have been evidenced between the passive layer composition investigated by XPS analysis and the corrosion behavior characterized by electrochemical techniques. The presence of silicon in the steel changes neither the oxidation state of chromium or iron, nor the ratio between iron and chromium in the passive layer. Silicon is present in the passive layer in an important content (35 at.%) and thus decreases the chromium content of the passive layer (80 and 50 at.% respectively for 304L steel and Uranus S1N after nitric passivation). Uranus S1N exhibits a less protective passive layer and so its generalized corrosion rate is higher than the one of 304L steel. A selective deposition of platinoïds highlights differences of polarization distribution on the surface between the grain boundaries and grain faces for theses steels. For Uranus S1N, the similar electrochemical behavior of grain boundaries and faces might be connected with the homogeneous silicon distribution.

Robin, R.; Miserque, F.; Spagnol, V.

2008-03-01

303

Correlation between composition of passive layer and corrosion behavior of high Si-containing austenitic stainless steels in nitric acid  

Energy Technology Data Exchange (ETDEWEB)

Austenitic stainless steels with 18% Cr have a good corrosion behavior in pure nitric acid. However, when oxidizing power of the solution increases, this kind of stainless steels faces a severe intergranular corrosion. Adding a sufficiently high concentration of silicon to the steel avoids this type of corrosion: in oxidizing solutions, those stainless steels exhibit generalized corrosion but their dissolution rate is higher than the one of stainless steels without silicon. To find out the role of silicon on such effects, the corrosion behavior of two different stainless steels with equivalent chromium content but with different silicon content (304L steel and Uranus S1N) has been studied in concentrated nitric acid solutions. Correlations have been evidenced between the passive layer composition investigated by XPS analysis and the corrosion behavior characterized by electrochemical techniques. The presence of silicon in the steel changes neither the oxidation state of chromium or iron, nor the ratio between iron and chromium in the passive layer. Silicon is present in the passive layer in an important content (35 at.%) and thus decreases the chromium content of the passive layer (80 and 50 at.% respectively for 304L steel and Uranus S1N after nitric passivation). Uranus S1N exhibits a less protective passive layer and so its generalized corrosion rate is higher than the one of 304L steel. A selective deposition of platinoids highlights differences of polarization distribution on the surface between the grain boundaries and grain faces for theses steels. For Uranus S1N, the similar electrochemical behavior of grain boundaries and faces might be connected with the homogeneous silicon distribution.

Robin, R. [CEA Saclay, DEN/DANS/DPC/SCCME, Bat. 458, 91191 Gif sur Yvette (France)], E-mail: rapheal.robin@cea.fr; Miserque, F. [CEA Saclay, DEN/DANS/DPC/SCP, Bat. 391, 91191 Gif sur Yvette (France); Spagnol, V. [CEA Saclay, DEN/DANS/DPC/SCCME, Bat. 458, 91191 Gif sur Yvette (France)

2008-03-30

304

Correlation between composition of passive layer and corrosion behavior of high Si-containing austenitic stainless steels in nitric acid  

International Nuclear Information System (INIS)

Austenitic stainless steels with 18% Cr have a good corrosion behavior in pure nitric acid. However, when oxidizing power of the solution increases, this kind of stainless steels faces a severe intergranular corrosion. Adding a sufficiently high concentration of silicon to the steel avoids this type of corrosion: in oxidizing solutions, those stainless steels exhibit generalized corrosion but their dissolution rate is higher than the one of stainless steels without silicon. To find out the role of silicon on such effects, the corrosion behavior of two different stainless steels with equivalent chromium content but with different silicon content (304L steel and Uranus S1N) has been studied in concentrated nitric acid solutions. Correlations have been evidenced between the passive layer composition investigated by XPS analysis and the corrosion behavior characterized by electrochemical techniques. The presence of silicon in the steel changes neither the oxidation state of chromium or iron, nor the ratio between iron and chromium in the passive layer. Silicon is present in the passive layer in an important content (35 at.%) and thus decreases the chromium content of the passive layer (80 and 50 at.% respectively for 304L steel and Uranus S1N after nitric passivation). Uranus S1N exhibits a less protective passive layer and so its generalized corrosion rate is higher than the one of 304L steel. A selective deposition of platinoids highlights differences of polarization distribution on the surface between the grain boundaries and grain faces for theses steels. For Uranus S1N, the similar electrochemical behavior of grain boundaries and faces might be connected with the homogeneous silicon distribution

305

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

306

Investigation of Corrosion and Cathodic Protection in Reinforced Concrete. I: Application of Electrochemical Techniques:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The electrochemical behavior of steel reinforcement in conditions of corrosion and cathodic protection was studied, using electrochemical impedance spectroscopy (EIS) and compared to reference (noncorroding) conditions. Polarization resistance (PR) method and potentiodynamic polarization (PDP) were employed as well, in addition to ac 2 pin electrical resistance monitoring, thus deriving a comparison of the involved parameters, mainly polarization resistance and bulk electrical properties, obt...

Koleva, D. A.; Wit, J. H. W.; Breugel, K.; Lodhi, Z. F.; Westing, E.

2007-01-01

307

Intergranular stress corrosion sensitivity in stabilized stainless steels  

International Nuclear Information System (INIS)

Stabilized stainless steels are used in ASEA-ATOM BWR's in a number of forged and casted components, viz. valve housings. Samples of steels that are Ti-stabilized have been analyzed for carbon, and then CERT-tested for intergranular stress corrosion (IGSCC). The steels tested are Sandvik 8R30 and VEW A700. The medium was water with 8 ppm O2 and at 286 degreeC, and a feed conductivity of less than 0.1?Scm-1. The tests show that the zone near welds in these stabilized steels which in strongly oxidizing acids are sensitive to knife line attack, are also in BWR systems sensitive to IGSCC. This type of corrosion can be inhibited by minimizing the carbon content of the steels. (Aa)

308

Corrosion of steel tanks in liquid nuclear wastes  

International Nuclear Information System (INIS)

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)

309

Microbiologically influenced corrosion of steels by thermophilic and mesophilic bacteria  

Energy Technology Data Exchange (ETDEWEB)

Bacterial influenced corrosion of AISI 316 stainless steels (SS) and ASTM A36 carbon steel by two strains of sulfate reducing bacteria (SRB) were analyzed. Thermophilic and mesophilic bacteria were isolated from the condensate fluid of ''Los Azufres'', a geothermal electric field located in the State of Michoacan at Central Mexico. Anaerobic corrosion tests were carried out for 15, 30 and 60 days in lactate-containing media at 50 C and 40 C. Scanning electron microscopy (SEM) was used to determine corrosion morphology. Pitting density was determined with an optical microscope. Corrosion potential, anodic potentiodynamic polarization curves and pH values were measured under anaerobic conditions. Results show that the microbial activity influenced the overall corrosion process, whereas, pitting corrosion and localized attack corrosion (LAC) were found. The anodic polarization curves show that passivation and activation processes should take place on the steel surface of the sample and pH decreases as the exposure time increases. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

Alfaro-Cuevas-Villanueva, R.; Cortes-Martinez, R.; Galvan-Martinez, R.; Torres-Sanchez, R. [Universidad Michoacana de San Nicolas de Hidalgo, Instituto de Investigaciones Metalurgicas, Edificio ' ' U' ' , C.U. Apartado Postal 52-B, CP, 58000, Morelia, Michoacan (Mexico); Garcia-Diaz, J.J. [Instituto Tecnologico de Morelia, Centro de Graduados, Morelia, Michoacan (Mexico)

2006-07-15

310

Electrochemical synthesis of polythiophene on nickel coated mild steel and corrosion performance  

Science.gov (United States)

Electrochemical polymerization of polythiophene (PTh) was investigated on nickel coated mild steel (MS) electrode, in LiClO 4 containing acetonitrile medium (ACN-LiClO 4). Nickel layer (1 ?m thick) was deposited galvanostatically, from a proper bath solution. Then, the synthesis of PTh film was achieved in 0.1 M thiophene containing ACN-LiClO 4, by using cyclic voltammetry technique. The corrosion performances of nickel coated samples with and without polymer top coats were investigated in 3.5% NaCl solution, by using electrochemical impedance spectroscopy (EIS) and anodic polarization curves. The nickel coating behaved like a physical barrier and provided some protection to MS against corrosion. But its barrier property diminished significantly with time and failed to protect MS. It was shown that PTh top coat improved the barrier efficiency remarkably, and excellent protection efficiency was obtained against MS corrosion, for considerable exposure time in such aggressive environment.

Tüken, T.; Yaz?c?, B.; Erbil, M.

2005-01-01

311

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

International Nuclear Information System (INIS)

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.

312

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

Energy Technology Data Exchange (ETDEWEB)

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.

Arganaraz, M.P. Quiroga; Ribotta, S.B. [INQUINOA-CONICET, Instituto de Quimica Fisica, Facultad de Bioquimica, Quimica y Farmacia, Universidad Nacional de Tucuman, Ayacucho 471, (4000) San Miguel de Tucuman (Argentina); Folquer, M.E., E-mail: mefolquer@fbqf.unt.edu.ar [INQUINOA-CONICET, Instituto de Quimica Fisica, Facultad de Bioquimica, Quimica y Farmacia, Universidad Nacional de Tucuman, Ayacucho 471, (4000) San Miguel de Tucuman (Argentina); Gassa, L.M.; Benitez, G.; Vela, M.E.; Salvarezza, R.C. [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Universidad Nacional de La Plata-CONICET, Suc. 4, C.C. 16, (1900) La Plata (Argentina)

2011-07-01

313

Inhibiting mild steel corrosion from sulfate-reducing and iron-oxidizing bacteria using gramicidin-S-producing biofilms.  

Science.gov (United States)

A gramicidin-S-producing Bacillus brevis 18-3 biofilm was shown to reduce corrosion rates of mild steel by inhibiting both the sulfate-reducing bacterium Desulfosporosinus orientis and the iron-oxidizing bacterium Leptothrix discophora SP-6. When L. discophora SP-6 was introduced along with D. orientis to a non-antimicrobial-producing biofilm control, Paenibacillus polymyxa ATCC 10401, a corrosive synergy was created and mild steel coupons underwent more severe corrosion than when only D. orientis was present, showing a 2.3-fold increase via electrochemical impedance spectroscopy (EIS) and a 1.8-fold difference via mass-loss measurements. However, when a gramicidin-S-producing, protective B. brevis 18-3 biofilm was established on mild steel, the metal coupons were protected against the simultaneous attack of D. orientis and L. discophora SP-6. EIS data showed that the protective B. brevis 18-3 biofilm decreased the corrosion rate about 20-fold compared with the non-gramicidin-producing P. polymyxa ATCC 10401 biofilm control. The mass loss for the protected mild steel coupons was also significantly lower than that for the unprotected ones (4-fold decrease). Scanning electron microscope images corroborated the corrosion inhibition by the gramicidin-S-producing B. brevis biofilm on mild steel by showing that the metal surface remained untarnished, i.e., the polishing grooves were still visible after exposure to the simultaneous attack of the sulfate-reducing bacterium and the iron-oxidizing bacterium. PMID:15278311

Zuo, Rongjun; Wood, Thomas K

2004-11-01

314

Corrosion inhibitor mechanisms on reinforcing steel in Portland cement pastes  

Science.gov (United States)

The mechanisms of corrosion inhibitor interaction with reinforcing steel are investigated in the present work, with particular emphasis on effects associated with corrosion inhibitors admixed into Portland cement paste. The principal objective in reinforcing steel corrosion inhibition for Portland cement concrete is observed to be preservation of the naturally passive steel surface condition established by the alkaline environment. Introduction of chloride ions to the steel surface accelerates damage to the passive film. Excessive damage to the passive film leads to loss of passivity and a destabilization of conditions that facilitate repair of the passive film. Passive film preservation in presence of chloride ions is achieved either through stabilization of the passive film or by modification of the chemical environment near the steel surface. Availability of inhibitors to the steel surface and their tendency to stabilize passive film defects are observed to be of critical importance. Availability of admixed corrosion inhibitors to the passive film is affected by binding of inhibitors during cement paste hydration. It is determined that pore solution concentrations of inorganic admixed inhibitors tend to be lower than the admixed concentration, while pore solution concentrations of organic admixed inhibitors tend to be higher than the admixed concentration. A fundamental difference of inhibitor function is observed between film-forming and defect stabilizing corrosion inhibitors. Experiments are conducted using coupons of reinforcing steel that are exposed to environments simulating chloride-contaminated Portland cement concrete. A study of the steel/cement paste interface is also performed, and compounds forming at this interface are identified using X-Ray diffraction.

Martin, Farrel James

2001-07-01

315

Erosion-corrosion of carbon steel in simulated tailing slurries  

International Nuclear Information System (INIS)

Research highlights: ? Physical model for predicting corrosion-enhanced erosion is established on basis of irreversible thermodynamics. ? The model for erosion-enhanced corrosion is modified to consider the non-uniform distribution of anodic dissolution over target surface. ? The models are validated by the in-situ microhardness measurement and erosion-corrosion tests. - Abstract: This paper investigates the synergism of mechanical and electrochemical factors in erosion-corrosion. The fact that active corrosion in the tailing slurry donates a small portion of total material loss indicates that the synergism results mainly from corrosion-enhanced erosion. As theoretically predicted, the erosion rates in corroding slurry under same hydrodynamic condition is a linear function of logarithmic corrosion rate, suggesting that the corrosion-induced surface plasticity is the dominate mechanism of corrosion-enhanced erosion. The reduced resistance to plastic deformation in surface layer while exposed to corroding media is demonstrated by the in situ micro-hardness measurements. The erosion-enhanced corrosion in flowing slurry of steel is a result of dynamic plastic deformation caused by erodent impingement.

316

Erosion-corrosion of carbon steel in simulated tailing slurries  

Energy Technology Data Exchange (ETDEWEB)

Research highlights: {yields} Physical model for predicting corrosion-enhanced erosion is established on basis of irreversible thermodynamics. {yields} The model for erosion-enhanced corrosion is modified to consider the non-uniform distribution of anodic dissolution over target surface. {yields} The models are validated by the in-situ microhardness measurement and erosion-corrosion tests. - Abstract: This paper investigates the synergism of mechanical and electrochemical factors in erosion-corrosion. The fact that active corrosion in the tailing slurry donates a small portion of total material loss indicates that the synergism results mainly from corrosion-enhanced erosion. As theoretically predicted, the erosion rates in corroding slurry under same hydrodynamic condition is a linear function of logarithmic corrosion rate, suggesting that the corrosion-induced surface plasticity is the dominate mechanism of corrosion-enhanced erosion. The reduced resistance to plastic deformation in surface layer while exposed to corroding media is demonstrated by the in situ micro-hardness measurements. The erosion-enhanced corrosion in flowing slurry of steel is a result of dynamic plastic deformation caused by erodent impingement.

Lu, B.T., E-mail: baotong.lu@swri.or [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alta., T6G 2G6 (Canada); Lu, J.F. [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alta., T6G 2G6 (Canada); Luo, J.L., E-mail: jingli.luo@ualberta.c [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alta., T6G 2G6 (Canada)

2011-03-15

317

Titanium containing high strength sulfuric acid corrosion resistant steel  

Energy Technology Data Exchange (ETDEWEB)

Ti containing low alloy steel free of Sb is found to have higher strength than and equivalent sulfuric acid corrosion (SAC) resistance to traditional SAC resistant steels in Cu-Cr-Sb system. SAC resistance of the Ti containing steel was investigated with potentiodynamic polarization, linear polarization resistance, electrochemical impedance spectroscopy, and weight loss measurements in a solution of 20 wt% H{sub 2}SO{sub 4} at 20 C. All measurements confirm that Ti addition is suitable for designing high strength SAC resistant steels. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Guo, Hairong; Li, Tingting; Li, Hualong; Toshihiko, Emi [Institute of Research of Iron and Steel, Shasteel, Zhangjiagang, Jiangsu (China)

2012-05-15

318

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

Directory of Open Access Journals (Sweden)

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.

Md. A. Aziz

2014-04-01

319

General corrosion of carbon steels in high temperature water; La corrosion generalisee des aciers au carbone dans l`eau a haute temperature  

Energy Technology Data Exchange (ETDEWEB)

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.

Gras, J.M.

1994-04-01

320

Stress Corrosion Cracking of FM Steels in Supercritical Water  

International Nuclear Information System (INIS)

As one of the Generation IV nuclear reactors, Supercritical Water Cooled Reactor (SCWR) is considered as a candidate reactor due to its high thermal efficiency. At above the supercritical condition of 374 .deg. C, 22.1 MPa, the supercritical water does not change the phase through the reactor core outlet. Then the high temperature coolant is effectively used at on over 40 % thermal efficiency. A critical step for this good feature to be attainable is to choose the proper structural materials. For an application of the structural materials to a core internal, fuel cladding, the materials should be evaluated in terms of their high temperature tensile strength, creep strength, corrosion and stress corrosion cracking susceptibility, radiation resistance, weldability, etc. Among the qualification items, stress corrosion cracking (SCC) tests of F/M steels have been performed in supercritical water environment. This work aims at evaluating stress corrosion cracking behavior of F/M steels as candidate materials for the SCWR

 
 
 
 
321

Corrosion testing of stainless steel-zirconium metal waste form  

International Nuclear Information System (INIS)

Stainless steel-zirconium (SS-Zr) alloys are being considered as waste forms for the disposition of metallic waste generated during the electrometallurgical treatment of spent nuclear fuel. The waste forms contain irradiated cladding hulls, components of the alloy fuel, noble metal fission products, and actinide elements. The baseline waste form is a stainless steel-15 wt% zirconium (SS-15Zr) alloy. This article presents microstructure and some of the corrosion studies being conducted on the waste form alloys. Electrochemical corrosion, immersion corrosion, and vapor hydration tests have been performed on various alloy compositions to evaluate corrosion behavior and resistance to selective leaching of simulated fission products. The SS-Zr waste forms are successful at the immobilization and retention of fission products and show potential for acceptance as high-level nuclear waste forms

322

Corrosion inhibition of mild steel by aerobic biofilm  

International Nuclear Information System (INIS)

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

323

Atomic Force Microscopy Study of Microbiologically Influenced Corrosion of Mild Steel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The anaerobic corrosion of mild steel in seawater was studied by atomic force microscopy (AFM). In the presence of sulfate reducing bacteria (SRB), corrosion was intensified and accelerated. A biofilm consists of heterogeneous microbial cells and extracellular polymeric substance with interstitial voids was observed on the surface of mild steel coupons. The greatest damage of steel occurred beneath the biofilm, in the form of pitting corrosion. The corrosion of steel can be quantified through...

Xu, Lc; Fang, Hhp; Chan, Ky

1999-01-01

324

Strain Aging of X100 Steel in Service and the Enhanced Susceptibility of Pipelines to Stress Corrosion Cracking  

Science.gov (United States)

In this study, experimental tests were performed to investigate the strain aging behavior of X100 pipeline steel in service and the resulting enhancement of susceptibility of pipelines to stress corrosion cracking (SCC). Results demonstrated that an immediate rise in temperature during coating application could result in strain aging of X100 steel, as indicated by increasing strength and decreasing elongation as well as the presence of Lüders strain during yielding. The aged steel is associated with an enhanced cracking susceptibility under cathodic protection potentials. It is believed that strain aging is able to enhance hydrogen evolution and the further permeation into steel, resulting in hydrogen-induced SCC of the steel.

Liang, Guangchuan; Peng, Xingyu; Juan, E. San; Cheng, Y. Frank

2013-12-01

325

Distinctive features of corrosion cracking of high-strength steels  

Energy Technology Data Exchange (ETDEWEB)

Experimental data on the corrosion cracking resistance of high-strength steel with a yield limit {sigma}{sub 0.2}{congruent} 1000 MPa in 3.5% NaCl solution are presented. It is shown that cracking resistance can be estimated by using the so-called net rated fracture stresses. Corrosion cracking in the surface layers of the metal operating in contact with the medium is explained by the suppression of the processes of plastic deformation.

Malyshev, V.N.; Potapov, V.V.

1994-07-01

326

Monitoring and characterization of corrosion processes on steel in concrete  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this thesis was to perform a critical comparison of a number of different electrochemical and physical methods for the monitoring of steel corrosion in concrete. Initially, some tests were performed on medium-sized reinforced-concrete columns located in a natural marine environment, into which electrical resistance probes were embedded. Electrochemical noise was measured using a five-electrode assembly, and corrosion potentials and rates were determined by the galvanostatic puls...

C?esen, Ales?

2013-01-01

327

Corrosion behavior of microwave-sintered austenitic stainless steel composites  

International Nuclear Information System (INIS)

This study compares the electrochemical response of austenitic stainless steel (316L) and yttrium aluminum garnet (YAG)-reinforced 316L composites microwave-sintered in solid-state (1200 deg. C) and supersolidus (1400 deg. C) condition. Compared with conventional sintering (through radiative heating), microwave sintering results in better corrosion resistance. This has been correlated with higher densification and microstructural attributes in the latter. The 316L-5YAG composites consolidated in microwave furnace at 1400 deg. Cyields the highest corrosion resistance

328

Corrosion behavior of microwave-sintered austenitic stainless steel composites  

Energy Technology Data Exchange (ETDEWEB)

This study compares the electrochemical response of austenitic stainless steel (316L) and yttrium aluminum garnet (YAG)-reinforced 316L composites microwave-sintered in solid-state (1200 deg. C) and supersolidus (1400 deg. C) condition. Compared with conventional sintering (through radiative heating), microwave sintering results in better corrosion resistance. This has been correlated with higher densification and microstructural attributes in the latter. The 316L-5YAG composites consolidated in microwave furnace at 1400 deg. Cyields the highest corrosion resistance.

Padmavathi, C. [Department of Materials and Metallurgical Engineering, Indian Institute of Technology, Kanpur, UP (India); Upadhyaya, A. [Department of Materials and Metallurgical Engineering, Indian Institute of Technology, Kanpur, UP (India)], E-mail: anishu@iitk.ac.in; Agrawal, D. [Materials Research Institute, The Pennsylvania State University, University Park, PA 16802 (United States)

2007-10-15

329

Corrosion enhanced erosion of steel in fresh concrete  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper deals with erosion-corrosion of steel in contact with flowing fresh concrete. Results of tests performed in fresh mortar on rotating cylindrical and disk electrodes are reported. The fresh mortar was manufactured by using chemical admixtures in order to retain constant workability during long time tests. Electrochemical and weight loss tests were conducted. SEM analysis was carried out to evaluate damage morphology. Damage mechanisms and corrosion behavior are discussed. Effect of ...

Cabrini, Marina; Lorenzi, Sergio; Marcassoli, Paolo; Pastore, Tommaso

2010-01-01

330

Steel corrosion assessment by electrochemical impedance on metakaolin blended mortars  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Since Corrosion of reinforcing steel in concrete is the cause of major economic losses, Portland cement has been traditionally replaced by cements blended with pozzalanic materials, most of which have been found to reduce the corrosion of steel. This paper shows the results of an experimental resear [...] ch aimed to investigate the corrosion of reinforcement in mortar using electrochemical impedance spectroscopy (EIS). For this, concrete laboratory samples containing a 0.0055 m steel bar and prepared with just ordinary Portland cement (OPC) and metakaolin at a replacement level of 20% were analyzed. In order to accelerate the steel corrosion process, all the samples were kept in a 3% NaCl solution and a constant anodic electrical potential was applied. Variations in the water to cementitious material ratio (0.5 and 0.6) and metakaolin proportion were analyzed, while the cementitious material to sand ratio was kept constant at 1:2.25 in all of the specimens. The results showed a reduction in corrosion rates when metakaolin was used as a blending admixture, especially at water to cementitious material ratio of 0.5.

Víctor, Triana; Juan, Lizarazo-Marriaga; Jhon Olaya, Flórez.

1457-14-01

331

/ Factorial design applied to corrosion of superduplex stainless steel  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: Spanish Abstract in spanish [...] Abstract in english Steels employed in offshore oil and gas production are subject to a very corrosive environment. Especially the new oilfields located in pre-salt layers imply the contact of steels with high brine concentration, high temperature and presence of corrosive gas such as CO2. Besides these facts, stainles [...] s steels have to present higher mechanical properties obtained from an optimized heat treatment. In order to take into account these factors and their synergisms, on the present paper, we have chosen a factorial experimental design to study the corrosion behavior of superduplex steel UNS S32750 by electrochemical tests. The results of open circuit potential, polarization curves and electrochemical impedance were analyzed with statistical methods considering a confidence level of 95%. The factors that significantly affect the corrosion potential are the carbon dioxide and heat treatment; the corrosion current is sensitive to carbon dioxide, and the resistance of polarization is strongly affected by the CO2 content.

T.J., Mesquita; R.P., Nogueira; I.N., Bastos.

2011-10-01

332

Electrochemical and weight-loss study of carbon steel corrosion  

International Nuclear Information System (INIS)

The Point Lepreau Generating Station (PLGS) will undergo an 18 month refurbishment project beginning in April, 2008. During this time, most of the carbon steel piping in the primary loop will be drained of water and dried. However, some water will remain during the shutdown due to the lack of drains in some lower points in the piping system. As a result, it is necessary to examine the effect of corrosion during the refurbishment. This study examined the effect of several variables on the corrosion rate of clean carbon steel. Specifically, the effect of oxygen in the system and the presence of chloride ions were evaluated. Corrosion rates were determined using both a weight-loss technique and electrochemical methods. The experiment was conducted at room temperature. The corrosion products from the experiment were analyzed using a Raman microscope. The results of the weight-loss measurements show that the corrosion rate of polished carbon steel is independent of both the presence of oxygen and chloride ions. The electrochemical method failed to yield meaningful results due to the lack of clearly interpretable data and the inherent subjectivity in the analysis. Lepidocricite was found to be the main corrosion product using the Raman microscope. (author)

333

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

International Nuclear Information System (INIS)

, 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.

334

Bio-corrosion in synthetic and natural sea water of modified stainless steels by poison elements  

International Nuclear Information System (INIS)

In seawater, bacteria can modify the behaviour of stainless steels towards corrosion. It can be then considered to control this type of degradation by a better adjustment of the chemical composition of the steels used. In this work, has been studied the influence of the addition of 'poisons' elements for bacteria on the bio-corrosion resistance of an austenitic 316L steel. The added elements were copper, tin and arsenic. After a bibliographic study and a description of the metallographic, electrochemical and surface analyses methods used, the results obtained in the considered media are given: synthetical seawater, natural, or sterilized and then inoculated. The specific role of each addition elements has then been revealed as well as the alteration of the protecting films and of the induced bio-film, and the behaviour differences in aerobic and anaerobic conditions. (O.M.)

335

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

International Nuclear Information System (INIS)

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

336

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

337

Corrosion of 316L stainless steels MAVL wastes containers  

International Nuclear Information System (INIS)

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.)

338

Stress corrosion of pure stainless steels in an alkaline solution  

International Nuclear Information System (INIS)

Stainless steel cracking in alkaline solutions is the cause of many problems in nuclear reactor technology and in sodium hydroxide and hydrogen industries using electrolysis processes. Resistance of Fe-, Cr-, Ni-steels to stress the corrosion with high purity of 20% Cr, 25% Ni in hot sodium hydroxide solutions is discussed. Studies on these alloys with one or several of other elements (C, N, P, Si, Mn, Ti, Mo) has also been performed. Finally, microscopic structure of these alloys in cold works has been assessed. The relation between stress corrosion and microscopic structure for some of the added elements to the alloys in sodium hydroxide solution is found

339

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

International Nuclear Information System (INIS)

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)

340

Corrosion of a carbon steel in simulated liquid nuclear wastes  

International Nuclear Information System (INIS)

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-bon 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 significant for A537 carbon steel in the concentration range of the solutions studied (pH 10-13) at 40 C degrees. The highest calculated corrosion rate for immersed samples, using the electrochemical impedance spectroscopy techniques, was 25 ?m/yr, while the highest calculated corrosion rate for vapor phase coupons, using weight-loss measurements, was 51 ?m/yr. On the contrary, it was found that A537 carbon steel was highly susceptible to localized attack, due to pitting and crevice corrosion, in the solutions and at the temperature studied. The highest penetration rates produced by pitting attack, measured by optical microscopy examination after 11 month immersion, were 0.3 mm/yr and 0.4 mm/yr for the immersed and the vapor phase coupons respectively. The highest penetration rate produced by crevice corrosion on the immersed coupons, measured by optical microscopy examination after 11 month immersion, was 1,1 mm/yr. Stress corrosion cracking signs were not observed after 11 month immersion on the U-bend coupons. (author)

 
 
 
 
341

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

International Nuclear Information System (INIS)

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.

342

A Study of Electrochemical Protection of Carbon Steels in Sulfuric Acid Solutions - Electrochemical Protection Diagrams of Metals (1) -  

International Nuclear Information System (INIS)

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

343

Case histories of microbiologically influenced corrosion of austenitic stainless steel weldments  

International Nuclear Information System (INIS)

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

344

The methodology of determining the corrosion of steel structures  

Directory of Open Access Journals (Sweden)

Full Text Available 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 algorithm for determining the corrosive wear is developed. An example of its application on a real object is shown.

S.D. Fedotov

2013-02-01

345

AFM evaluation for corrosion behavior of ion irradiated stainless steel  

International Nuclear Information System (INIS)

Development and research about analytical method for the study of irradiation assisted stress corrosion cracking (IASCC) of austenitic stainless steel was conducted. Specimens were irradiated by Ni3+ ions at 573 to 673K up to dose level of 35 dpa with synergetic implantation of He ions. The specimens were etched in H2SO4 solution at a constant potential, and then corroded positions were evaluated by atomic force microscope (AFM) and electron backscatter diffraction pattern (EBSP) technique. The developed method could quantitatively evaluate irradiation effects on corrosion behavior. He implantation reduced corrosion rate. (author)

346

Effect of liquid metals velocity on corrosion rate of steels  

International Nuclear Information System (INIS)

The nature of liquid-metal coolant velocity on corrosion of steel is considered. The model describing transition from diffusion to kinetic mechanism of liquid metal corrosion under Re number near 105 is proposed, the viscous sublayer plays the main role. The model is suitable for both alkali (Li-Cs, Na+K) and heavy liquid metal (Hg, Bi, Pb, Sn, Ga, Pb+Bi) coolants. It is shown that under velocity variance in wide Re number range various liquid metals have mutual regularities of corrosion rate change

347

Corrosion studies of stainless steel 316L, modified by ion beam techniques, under simulated physiological conditions  

Energy Technology Data Exchange (ETDEWEB)

Stainless steel 316L is a commonly used material for medical implants in orthopaedic surgery. In order to improve its performance in biological surroundings, metallic coatings (Au, Ag, Cu and Zn) were deposited by evaporation (vapour deposition) followed by ion beam mixing. Ceramic coatings (Al{sub 2}O{sub 3}) were produced by ion beam-assisted deposition. As protection against galvanic corrosion of the 316L bulk material in contact with noble metals, an alumina layer was deposited on to the bulk material and afterwards the coatings with noble metals were carried out. Potentiostatic and potentiodynamic corrosion experiments in physiological sodium chloride solution and in human plasma showed interesting differences in the corrosion behaviour between these two electrolytes. Coatings with a high corrosion protection in human plasma sometimes showed poor corrosion protection in physiological sodium chloride solution. These findings are discussed on the basis of the electrochemical properties of the systems. The combination of alumina and silver coatings showed the best results in electrochemical corrosion evaluations in both solutions. (orig.) 15 refs.

Meinert, K.; Wolf, G.K. [Heidelberg Univ. (Germany). Physikalisch-Chemisches Inst.

1998-01-01

348

Influence of hot water conditioning on the corrosion behavior of carbon steel  

Energy Technology Data Exchange (ETDEWEB)

The effect of hot water conditioning on the corrosion behavior of carbon steel in aqueous solutions of sodium chloride has been examined. In particularly, it has been examined the effect of water conditioning in the presence of octadecylamine = ODA on the corrosion and passivation of carbon steel, which was a major point in this research because of the big interest in the improvement of the hot water corrosion situation in electric and heating power stations of development countries, where a lot of damage is produced on the walls of the heat exchangers. It has been tried to determine which conditioning methods are working to improve the corrosion resistance and also to remove the deposits. Because it is known that ODA = Octadecylamine improves the corrosion resistance (it does not allow the formation of thick layers and also removes the deposits), it has been tried to develop a method of hot water conditioning by using ODA. For examining the corrosion behavior and the resistance of these materials electrochemical techniques have been used: DC - Potentiodynamic scanning AC - Electrochemical impedance spectroscopy (EIS) Scanning electron microscopy (SEM) was applied to determine the morphology of the oxide layers. Additionally, the electrolytes after hot water conditioning were analyzed for dissolved iron. The most important results are: 1. Hydrazine conditioning reveals in pure hot water much lower corrosion than oxygen conditioning. 2. ODA addition retards the corrosion much more in the case of hydrazine conditioning, than in the case of oxygen conditioning. 3. Hot water conditioning in the case of carbon steel does not form protective oxide layers resistant to 0.01 m Cl{sup -}-solution (low polarization resistance, no passive range). 4. ODA showed no beneficial effect on the anodic branch of the polarization curve in 0.01 m Cl{sup -}-solution, but it reduced the cathodic currents. (orig.)

Banica, C.E. [Inst. of Atomic Physics, Inst. of Optoelectronics, IOEL-SA, Bucharest (Romania); Inst. of Solid State and Materials Research, IFW, Dresden (Germany); Czempik, E. [REICON, Leipzig (Germany); Vogt, C.; Schneider, F. [Inst. of Solid State and Materials Research, IFW, Dresden (Germany)

2002-04-01

349

Biopolymer Corrosion Inhibition of Mild Steel: Electrochemical/Moessbauer Results  

International Nuclear Information System (INIS)

Metallic corrosion is the destructive attack of a metal by its environment. Organic inhibitors, amongst others, adsorb directly onto the surface of the metal and can thus inhibit corrosion. Chitosan, tri-methyl chitosan and dodecyl amine hydrochloride were studied with a view to assessing their potential use as adsorption inhibitors for mild steel in acid chloride and sulphate solutions. The inhibition efficiency was studied successfully by potentiostatic polarisation (Tafel plots), Moessbauer spectroscopy (CEMS and transmission) and corrosion experiments in static acidified electrolytes. Inhibition efficiencies ranged from 20 to 93%. The chemical compositions of the corrosion products were determined by means of Moessbauer spectroscopy, which identified iron hydroxides as the main corrosion products forming in the presence of the inhibitors.

350

Biopolymer Corrosion Inhibition of Mild Steel: Electrochemical/Moessbauer Results  

Energy Technology Data Exchange (ETDEWEB)

Metallic corrosion is the destructive attack of a metal by its environment. Organic inhibitors, amongst others, adsorb directly onto the surface of the metal and can thus inhibit corrosion. Chitosan, tri-methyl chitosan and dodecyl amine hydrochloride were studied with a view to assessing their potential use as adsorption inhibitors for mild steel in acid chloride and sulphate solutions. The inhibition efficiency was studied successfully by potentiostatic polarisation (Tafel plots), Moessbauer spectroscopy (CEMS and transmission) and corrosion experiments in static acidified electrolytes. Inhibition efficiencies ranged from 20 to 93%. The chemical compositions of the corrosion products were determined by means of Moessbauer spectroscopy, which identified iron hydroxides as the main corrosion products forming in the presence of the inhibitors.

Waanders, F. B., E-mail: chifbw@puknet.puk.ac.za; Vorster, S. W.; Geldenhuys, A. J. [PU for CHE, School of Chemical and Minerals Engineering (South Africa)

2002-03-15

351

Accelerated hot corrosion studies of cold spray Ni-50Cr coating on boiler steels  

International Nuclear Information System (INIS)

In the current investigation Ni-50Cr powder was deposited on two boiler steels SA-213-T22 and SA 516 (Grade 70) by cold spray process. The hot corrosion performance of coated as well as bare boiler steels was evaluated in an aggressive environment of Na2SO4-60% V2O5 under cyclic conditions at an elevated temperature of 900 oC. The kinetics of the corrosion was approximated by the weight change measurements made after each cycle for a total period of 50 cycles. Each cycle consisted of 1 h heating in a tube furnace followed by 20 min cooling in ambient air. X-ray diffraction (XRD), scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDAX) techniques were used to analyse the corrosion products. Both the uncoated boiler steels suffered intensive spallation in the form of removal of their oxide scales, which may be attributed to the formation of unprotective Fe2O3 dominated oxide scales. The Ni-50Cr coated steels showed lesser weight gains and the oxide scales remained intact till the end of the experiment. The phases revealed in the oxide scales of the coated specimens were mainly oxides of chromium and nickel and their spinels which are reported to be protective against the hot corrosion.

352

Corrosion mechanisms of austenitic stainless steels in nitric media used in reprocessing plants  

Science.gov (United States)

Austenitic stainless steels type 304L, 316L and 310Nb are largely used as structural materials for equipments handling nitric acid media in reprocessing plants. In almost all nitric media, these materials, protected by a chromium(III) oxide rich layer, remain in their passive state. However, in some particular nitric media, their corrosion potential may be shifted towards their transpassive domain. In this domain, they can suffer intergranular corrosion, even though they are not sensitized owing to their very low carbon content. The corrosion potential of the steel depends greatly on the cathodic reaction involved in the oxido-reduction process between the elements Fe, Cr, Ni of the steel and the oxidizing species of the medium. Three cases of an increase in the corrosion potential can be found in reprocessing media: pure nitric acid-water solutions, in which the cathodic reaction is the reduction reaction of HNO 3; nitric acid media containing oxidizing species, in which the cathodic reaction is the reaction of reduction of the oxidizing species into the reduced one; nitric media containing metallic elements electrochemically more noble than the steels, causing galvanic coupling. In each case, the mechanism and the relevant situations we experimentally studied are described.

Fauvet, P.; Balbaud, F.; Robin, R.; Tran, Q.-T.; Mugnier, A.; Espinoux, D.

2008-03-01

353

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

International Nuclear Information System (INIS)

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.

354

Significance of steel electrical resistance method in the evaluation of reinforcement corrosion in cementitious systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The suitable detection system of steel reinforcement corrosion in concrete structures contributes to the reduction of their maintenance costs. Method of steel electrical resistance represents non-destructive monitoring of steel in cementitious systems. Specially prepared and arranged test specimen of steel as a corrosion sensor is embedded in mortar specimen. Verification tests of this method based on chloride corrosion of steel in mortars as well as its visual inspection are introduced. Sign...

Krajci, L.; Janotka, I.

2004-01-01

355

Effect of chlorides on the corrosion behaviour of mild steel  

International Nuclear Information System (INIS)

closed system such as in crevice. In addition to acidification of MgCl2 soln., the formation of non-protective magnetite film by Mg2+ ion was estimated to be a reason of accelerated corrosion. (author)

356

Corrosion protection of a commercial NdFeB magnet by phosphating  

Energy Technology Data Exchange (ETDEWEB)

NdFeB magnets are susceptible to corrosion in normal working environments and are therefore protected against corrosion with coatings of epoxies, electrodeposited nickel, etc. Eventual failure of these coatings expose the surface of the magnet to corrosion. Hence, protection of magnets prior to the application of coatings is one way of overcoming the corrosion problems associated with coating failures. Phosphating is a well known process to protect carbon steels and other ferrous alloys in general, and is often used as a pretreatment before the application of coatings. This study reports the experimental work carried out to obtain a corrosion inhibiting layer directly on NdFeB magnet surfaces, that is also structurally coherent with the substrate. The electrochemical characteristics of the surface layer on the bare magnet surface, obtained by immersion in a solution of 0.15 M NaH{sub 2}PO{sub 4} and acidified with H{sub 2}SO{sub 4}, was determined. The corrosion resistance of the layer was tested in a solution of 1%(wt) NaCl plus 5 mM H{sub 2}SO{sub 4} with pH of 2.9, by electrochemical impedance spectroscopy (EIS) and cyclic polarization tests. The results indicated that NdFeB magnets can be protected in fairly aggressive media by a phosphate layer. Anodic polarization measurements indicated breakdown of the phosphate layer and corrosion of the magnet, only at an overpotential of approximately 400 mV. (orig.)

Saliba-Silva, A.M.; Costa, I. [IPEN, Inst. de Pesquisas Energeticas e Nucleares, Cidade Univ., Sao Paulo, SP (Brazil)

2001-07-01

357

Resistance of WWER vessel steel to stress corrosion  

International Nuclear Information System (INIS)

Crack resistance of 15Kh2MFA steel samples, irradiated in the medium of the IRT-2000 reactor core coolant, is investigated. The tests were carried out in circulating distilled water with the addition of boric acid at 290 deg C and under the pressure of 14 MPa for 1500 h. The test results have shown that under the given conditions in the 15Kh2MFA vessel steel no growth of corrosion cracks takes place

358

Effect of carbon content and tempering structures on the electrochemical and corrosion properties of carbon steels  

International Nuclear Information System (INIS)

The effect of carbon content, hardening structures and internal stresses occuring in the result of carbonic steel heat treatment on their electrochemical and corrosion properties is investigated. The corrosion rate is shown to be increased in 6% H2SO4 and 3% NaCl with the increase of carbon content and in respect to internal stresses arising in the result of heat treatment, in transition from perlite, to sorbite, troostite- and martensite. The inhibitor protection is most effective in the case of perlite-ferrite structure; the effectiveness of the inhibitor protection decreases in transition to highly resistant structures. The electrochemical properties of steels also depend on carbon content and hardening structures

359

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

360

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

International Nuclear Information System (INIS)

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.

 
 
 
 
361

Crevice corrosion control for stainless steel using radiation-induced surface activation  

International Nuclear Information System (INIS)

When a semiconductor film is irradiated by ?-rays, excited electrons are transferred to a base metal in contact with the film, resulting in cathodic-anodic reactions and surface activation of the metal oxide film. The authors first produced radiation-induced surface activation (RISA) in 2000 and have used it in the development of a new corrosion protection method. This report describes a corrosion mitigation technique based on RISA to prevent crevice corrosion in stainless steel, using low-intensity radiation. Experimental results show that an electrode potential of -100 mV vs. Ag/AgCl was produced and maintained on TiO2-coated SUS304 stainless steel specimens immersed in artificial seawater and in close contact with a small, sealed 60Co source (external irradiation) or activated by neutron irradiation to become self-exciting, with no corrosion observed for more than 7 days. In contrast, the potential of a specimen without a radiation source decreased to less than -280 mV vs. Ag/AgCl and crevice corrosion occurred beneath the O-ring within a few days. The corrosion control mechanism was explored by measurement of dissolved oxygen and iron ions in the solution. (author)

362

A liquid aluminum corrosion resistance surface on steel substrate  

Energy Technology Data Exchange (ETDEWEB)

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 {alpha}-Al{sub 2}O{sub 3}, followed by a thinner layer of FeAl{sub 3}, and then a much thicker one of Fe{sub 2}Al{sub 5} 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.

Wang Deqing; Shi Ziyuan; Zou Longjiang

2003-05-31

363

Evaluation of Corrosion Protection for Epoxy and Urethane Coating by EIS under Various Cyclic Corrosion Tests  

International Nuclear Information System (INIS)

Protective coatings play an important role in the protection of metallic structures against corrosive environment. The main function of anticorrosive coating is to prevent the materials from corrosive agents, such as water, oxygen and ions. In the study, the corrosion protection properties of urethane and epoxy coating systems were evaluated using EIS methods exposed to the corrosion acceleration test such as Norsok M501, Prohesion and hygrothermal cyclic test. AFM analysis of the coating systems was carried out to monitor the change of roughness of coatings. Urethane coating system was more stable than the epoxy coating under given cyclic conditions. Water uptake into the urethane coatings was less than that into the epoxy coating. The urethane coating system showed better corrosion protection than epoxy coating system based on the changes of the impedance modulus at low frequency region with exposure time. Consequently, the corrosion protection properties of the epoxy and urethane coatings was well correspond with their surface roughness changes and water uptakes

364

Stress corrosion cracking susceptibility of dissimilar stainless steels welded joints  

Directory of Open Access Journals (Sweden)

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.

J. ?abanowski

2007-01-01

365

Corrosion Inhibition and Adsorption of Anthocleista Djalonesis Leaf Extract on the Acid Corrosion of Mild Steel  

Scientific Electronic Library Online (English)

Full Text Available SciELO Portugal | Language: English Abstract in english Aqueous extracts of the leaves of Anthocleista djalonesis (AD) have been investigated as non toxic corrosion inhibitors for mild steel in acidic environments (1 M HCl and 0.5 M H2SO4, respectively). Corrosion rates were evaluated at 30 °C using the weight loss, electrochemical impedance spectroscopy [...] and potentiodynamic polarization techniques. AD extract was found to inhibit mild steel corrosion in both acidic media via adsorption of the extract organic matter on the metal/solution interface. Polarization data indicate that the extract functioned via a mixed inhibition mechanism, affecting both the cathodic and anodic partial reactions of the corrosion process. Molecular dynamics (MD) simulations were performed to illustrate the adsorption process of some specific components of the extract.

C.E., Ogukwe; C.O., Akalezi; M. A., Chidiebere; K.L., Oguzie; Z.O., Iheabunike; E.E., Oguziea.

2012-05-01

366

Sol-gel TiO2-SiO2 films as protective coatings against corrosion of 316L stainless steel in H2SO4 solutions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sol-gel TiO2-SiO2 films were deposited on 316L stainless steel by dip coating process from a sono-catalysed sol of composition 30TiO2-70SiO2 prepared from a mixture of Ti(OC2H5)4 and Si(OC2H5)4, absolute ethanol C2H5OH and glacial acetic acid CH3COOH as precursors and solvents. The films, densified at 800° C in air for 2 h, are composed of small orthorhombic titania (anatase) crystallites embedded in a SiO2 amorphous matrix as identified by X-ray diffraction. The temperature dependence of th...

Atik, Mohamed; Lima Neto, Pedro; Aegerter, Michel A.; Avaca, Luis A.

1995-01-01

367

Alloy steel corrosion kinetics and oxide morphologies in acid chloride environments  

International Nuclear Information System (INIS)

The denting of PWR primary water tubes as a result of corrosive attack of the mild steel support plates has led to extensive research into the mechanism of corrosion and a search for palliatives to ease the problem. In the current design of steam generators the mild steel drilled hole tube support plate has been replaced by one of quatrefoil or trifoil shape made of ferritic stainless steel (12%Cr) to ensure that the plates are less vulnerable to attack in the event of adverse boiler water chemistry. The oxide volume is again approximately twice that of the metal consumed but the corrosion mechanism is different from that of the mild steel in that a duplex oxide is formed consisting of an inner chromium rich (FeCr)3O4 layer surmounted by an outer Fe3O4 layer of similar thickness. This study was initiated to investigate the mechanisms of oxide growth and the transition between protective and rapid linear oxidation in order to validate the use of chromium steels for resistance to acid chloride attack and to establish a confidence margin in terms of chromium content and environment

368

Stainless steel corrosion by molten nitrates : analysis and lessons learned.  

Energy Technology Data Exchange (ETDEWEB)

A secondary containment vessel, made of stainless 316, failed due to severe nitrate salt corrosion. Corrosion was in the form of pitting was observed during high temperature, chemical stability experiments. Optical microscopy, scanning electron microscopy and energy dispersive spectroscopy were all used to diagnose the cause of the failure. Failure was caused by potassium oxide that crept into the gap between the primary vessel (alumina) and the stainless steel vessel. Molten nitrate solar salt (89% KNO{sub 3}, 11% NaNO{sub 3} by weight) was used during chemical stability experiments, with an oxygen cover gas, at a salt temperature of 350-700 C. Nitrate salt was primarily contained in an alumina vessel; however salt crept into the gap between the alumina and 316 stainless steel. Corrosion occurred over a period of approximately 2000 hours, with the end result of full wall penetration through the stainless steel vessel; see Figures 1 and 2 for images of the corrosion damage to the vessel. Wall thickness was 0.0625 inches, which, based on previous data, should have been adequate to avoid corrosion-induced failure while in direct contact with salt temperature at 677 C (0.081-inch/year). Salt temperatures exceeding 650 C lasted for approximately 14 days. However, previous corrosion data was performed with air as the cover gas. High temperature combined with an oxygen cover gas obviously drove corrosion rates to a much higher value. Corrosion resulted in the form of uniform pitting. Based on SEM and EDS data, pits contained primarily potassium oxide and potassium chromate, reinforcing the link between oxides and severe corrosion. In addition to the pitting corrosion, a large blister formed on the side wall, which was mainly composed of potassium, chromium and oxygen. All data indicated that corrosion initiated internally and moved outward. There was no evidence of intergranular corrosion nor were there any indication of fast pathways along grain boundaries. Much of the pitting occurred near welds; however this was the hottest region in the chamber. Pitting was observed up to two inches above the weld, indicating independence from weld effects.

Kruizenga, Alan Michael

2011-09-01

369

Cesium corrosion process in Fe–Cr steel  

International Nuclear Information System (INIS)

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(?G650°C=-894.1kJ/mol) and Cr23C6+46Cs+46O2?23Cs2CrO4+6C(?G650°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

370

Protection of well equipment against acetic acid corrosion  

Energy Technology Data Exchange (ETDEWEB)

A study was made of the effect that the surfactant OP-10 has on corrosion. It was shown to possess a protective capability but insufficient to suppress fully the corrosion processes. When the water-soluble corrosion inhibitors VRI and IKB-4 were added to an aqueous solution of OP-10, the protective effect of the mixture significantly increased. 2 references, 1 figure, 2 tables.

Kutovaya, A.A.; Obukhova, Z.P.; Miroshnichenko, O.A.; Kuzhetsov, V.P.

1978-12-01

371

Ductility of reinforcing steel with different degrees of corrosion and the 'equivalent steel' criterion  

Digital Repository Infrastructure Vision for European Research (DRIVER)

One of the most significant effects of reinforcing steel corrosion on reinforced concrete structures is the decline in the ductility-related properties of the steel. Such properties condition the behaviour of reinforced concrete structures and must be taken into account when re-engineering corroded members, for even the analytical approach itself may be determined on these grounds. The present experimental study addresses the variation in the ductility of concrete-embedded steel bars when e...

Moreno Ferna?ndez, E.; Cobo Escamilla, A.; Ferna?ndez Ca?novas, M.

2007-01-01

372

Stainless steel stress corrosion in acid solutions and its inhibition  

International Nuclear Information System (INIS)

The influence of different organic inhibitors on the overall corrosion rate and on the morphology of attack was studied on U-shaped samples of austenitic stainless steels (AISI 304 and 316) in solutions of H2SO4+NaCl or HCl at different concentrations

373

Ambient temperature stress-corrosion cracking of sensitized stainless steels  

International Nuclear Information System (INIS)

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

374

Polyethersulfone Coating for Mitigating Corrosion of Steel in Geothermal Environment.  

Science.gov (United States)

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 bri...

T. Sugama

2005-01-01

375

Pitting and crevice corrosion of stainless steels in chloride solutions  

International Nuclear Information System (INIS)

In practice stainless steels in chloride containing waters are found to be susceptible to crevice corrosion and pitting. Corrosion tests were carried out on AISI 304 L stainless using a simulated crevice and the compositions of the electrolyte in the crevice determined. Long term potentiostatic tests were used to determine the critical potentials for crevice corrosion (Usub(S)), for various steels in sodium chloride solutions at different concentrations and temperatures. The steels studied were 22 CrMoV 121, X 22 CrNi 17 and AISI 304 L. Like the critical pitting potential (Usub(L)), Usub(S) was found to have a strong dependence on the chloride content of the external solution. At higher concentrations the two potentials were similar. At lower concentrations the Usub(S) was lower than Usub(L). The knowledge of these critical potentials together with well known rest potentials for a steel in an electrolyte of known concentration, allows conclusions to be drawn about its susceptibility to pitting and crevice corrosion. The method is suitable also for other passive metals. (orig.)

376

The anaerobic corrosion of carbon steel in concrete  

International Nuclear Information System (INIS)

The report describes the work of a two year programme investigating the anaerobic corrosion of carbon steel embedded in a range of candidate repository cements and concretes at laboratory temperatures. The factors investigated in the study were the rate of the anaerobic corrosion reaction, the effect of hydrogen overpressure on the reaction rate and the form of the corrosion product. Both electrochemical and sample weight loss corrosion rate measurements were used. The cements and concretes used were prepared both with and without small additions of chloride (2% by weight of mix water). The results indicate that the corrosion rate is low, < 1 ?m/year, the effect of hydrogen overpressure is not significant over the range of pressures investigated, 1-100 atmospheres, and that the corrosion product is dependent on the cement used to cast the samples. Magnetite was identified in the case of blast furnace slag replacement cements but for pulverised fuel ash and ordinary Portland cements no corrosion product was evident either from X-ray diffraction or laser Raman measurements. Further work is presently underway to investigate the effects of elevated temperatures and chloride levels on the anaerobic corrosion reaction and the rate of hydrogen gas production. (author)

377

Corrosion resistance properties of sintered duplex stainless steel  

Directory of Open Access Journals (Sweden)

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 order to examine different cooling rates.Originality/value: The use of elemental powders added to a stainless steel base showed its potentialities, in terms of fair compressibility and final sintered density. In addition a good microstructural homogeneity and first of all corrosion resistance was achieved, also working with cycles possible for industries.

L.A. Dobrza?ski

2006-09-01

378

Effect of H2S on the CO2 corrosion of carbon steel in acidic solutions  

International Nuclear Information System (INIS)

The objective of this study is to evaluate the effect of low-level hydrogen sulfide (H2S) on carbon dioxide (CO2) corrosion of carbon steel in acidic solutions, and to investigate the mechanism of iron sulfide scale formation in CO2/H2S environments. Corrosion tests were conducted using 1018 carbon steel in 1 wt.% NaCl solution (25 oC) at pH of 3 and 4, and under atmospheric pressure. The test solution was saturated with flowing gases that change with increasing time from CO2 (stage 1) to CO2/100 ppm H2S (stage 2) and back to CO2 (stage 3). Corrosion rate and behavior were investigated using linear polarization resistance (LPR) technique. Electrochemical impedance spectroscopy (EIS) and potentiodynamic tests were performed at the end of each stage. The morphology and compositions of surface corrosion products were analyzed using scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The results showed that the addition of 100 ppm H2S to CO2 induced rapid reduction in the corrosion rate at both pHs 3 and 4. This H2S inhibition effect is attributed to the formation of thin FeS film (tarnish) on the steel surface that suppressed the anodic dissolution reaction. The study results suggested that the precipitation of iron sulfide as well as iron carbonate film is possible in the acidion carbonate film is possible in the acidic solutions due to the local supersaturation in regions immediately above the steel surface, and these films provide corrosion protection in the acidic solutions.

379

Corrosion behavior of stainless steel-zirconium alloy waste forms  

International Nuclear Information System (INIS)

Stainless steel-zirconium (SS-Zr) alloys are being considered as waste forms for the disposal of metallic waste generated during the electrometallurgical treatment of spent nuclear fuel. The baseline waste form for spent fuels from the EBR-II reactor is a stainless steel-15 wt.% zirconium (SS-15Zr) alloy. This article briefly reviews the microstructure of various SS-Zr waste form alloys and presents results of immersion corrosion and electrochemical corrosion tests performed on these alloys. The electrochemical tests show that the corrosion behavior of SS-Zr alloys is comparable to those of other alloys being considered for the Yucca Mountain geologic repository. The immersion tests demonstrate that the SS-Zr alloys are resistant to selective leaching of fission product elements and, hence, suitable as candidates for high-level nuclear waste forms

380

New findings on intergranular corrosion mechanism of stabilized stainless steels  

International Nuclear Information System (INIS)

Number of different sets of stabilized both ferritic and austenitic stainless steels with various alloying elements were evaluated to verify new findings on the intergranular corrosion mechanism. The intergranular segregation and precipitation were analyzed by using a transmission electron microscopy with an energy dispersive X-ray spectroscopy and a laser assisted three-dimensional atom probe. On the basis of the current result, it is newly proposed that the intergranular corrosion occurring in the stabilized both ferritic and austenitic stainless steels is induced by Cr-depletion due to segregation of un-reacted Cr atoms around carbides of stabilizer elements (Ti or Nb) along the grain boundary, but not due to formation of Cr-carbide. A prevention method for this type of intergranular corrosion is also suggested after critical evaluation on the effect of Cr, C, and Ni.

 
 
 
 
381

New findings on intergranular corrosion mechanism of stabilized stainless steels  

Energy Technology Data Exchange (ETDEWEB)

Number of different sets of stabilized both ferritic and austenitic stainless steels with various alloying elements were evaluated to verify new findings on the intergranular corrosion mechanism. The intergranular segregation and precipitation were analyzed by using a transmission electron microscopy with an energy dispersive X-ray spectroscopy and a laser assisted three-dimensional atom probe. On the basis of the current result, it is newly proposed that the intergranular corrosion occurring in the stabilized both