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Sample records for iron corrosion products

  1. Degradation of trichloronitromethane by iron water main corrosion products.

    PubMed

    Lee, Jeong-Yub; Pearson, Carrie R; Hozalski, Raymond M; Arnold, William A

    2008-04-01

    Halogenated disinfection byproducts (DBPs) may undergo reduction reactions at the corroded pipe wall in drinking water distribution systems consisting of cast or ductile iron pipe. Iron pipe corrosion products were obtained from several locations within two drinking water distribution systems. Crystalline-phase composition of freeze-dried corrosion solids was analyzed using X-ray diffraction, and ferrous and ferric iron contents were determined via multiple extraction methods. Batch experiments demonstrated that trichloronitromethane (TCNM), a non-regulated DBP, is rapidly reduced in the presence of pipe corrosion solids and that dissolved oxygen (DO) slows the reaction. The water-soluble iron content of the pipe solids is the best predictor of TCNM reaction rate constant. These results indicate that highly reactive DBPs that are able to compete with oxygen and residual disinfectant for ferrous iron may be attenuated via abiotic reduction in drinking water distribution systems.

  2. Iron Drinking Water Pipe Corrosion Products: Concentrators of Toxic Metals

    DTIC Science & Technology

    2013-01-01

    Toxic Metals Tammie L. Gerke and J. Barry Maynard Department of Geology University of Cincinnati Cincinnati, OH, 45221-0013 USA Todd P. Luxton and...Kirk G. Scheckel U.S. Environmental Protection Agency, ORD, NRMRL, LRPCD 26 West Martin Luther King Dr. Cincinnati, OH, 45268 USA Brenda J...Little Naval Research Laboratory Stennis Space Center, MS 39525 USA ABSTRACT The capability of iron pipe corrosion products in active drinking water

  3. Role of humic substances in the formation of nanosized particles of iron corrosion products

    NASA Astrophysics Data System (ADS)

    Pankratov, D. A.; Anuchina, M. M.

    2017-02-01

    The corrosion of metallic iron in aqueous solutions of humic substances (HS) with limited access to air is studied. The HS are found to exhibit multiple functions. Acid-base, redox, and surfactant properties, along with the ability to form complexes with iron in solution, are displayed in the corrosion process. Partial reduction of the HS during the corrosion reaction and their adsorption onto the main corrosion product (Fe3O4 nanoparticles) are observed.

  4. Speciation and distribution of vanadium in drinking water iron pipe corrosion by-products

    SciTech Connect

    Gerke, Tammie L.; Scheckel, Kirk G.; Maynard, J. Barry

    2010-11-12

    Vanadium (V) when ingested from drinking water in high concentrations (> 15 {micro}g L{sup -1}) is a potential health risk and is on track to becoming a regulated contaminant. High concentrations of V have been documented in lead corrosion by-products as Pb{sub 5}(V{sup 5+}O{sub 4}){sub 3}Cl (vanadinite) which, in natural deposits is associated with iron oxides/oxyhydroxides, phases common in iron pipe corrosion by-products. The extent of potential reservoirs of V in iron corrosion by-products, its speciation, and mechanism of inclusion however are unknown. The aim of this study is to assess these parameters in iron corrosion by-products, implementing synchrotron-based {mu}-XRF mapping and {mu}-XANES along with traditional physiochemical characterization. The morphologies, mineralogies, and chemistry of the samples studied are superficially similar to typical iron corrosion by-products. However, we found V present as discrete grains of Pb{sub 5}(V{sup 5+}O{sub 4}){sub 3}Cl likely embedded in the surface regions of the iron corrosion by-products. Concentrations of V observed in bulk XRF analysis ranged from 35 to 899 mg kg{sup -1}. We calculate that even in pipes with iron corrosion by-products with low V concentration, 100 mg kg{sup -1}, as little as 0.0027% of a 0.1-cm thick X 100-cm long section of that corrosion by-product needs to be disturbed to increase V concentrations in the drinking water at the tap to levels well above the 15 {micro}g L{sup -1} notification level set by the State of California and could adversely impact human health. In addition, it is likely that large reservoirs of V are associated with iron corrosion by-products in unlined cast iron mains and service branches in numerous drinking water distribution systems.

  5. Speciation and distribution of vanadium in drinking water iron pipe corrosion by-products.

    PubMed

    Gerke, Tammie L; Scheckel, Kirk G; Maynard, J Barry

    2010-11-01

    Vanadium (V) when ingested from drinking water in high concentrations (>15 μg L(-1)) is a potential health risk and is on track to becoming a regulated contaminant. High concentrations of V have been documented in lead corrosion by-products as Pb(5)(V(5+)O(4))(3)Cl (vanadinite) which, in natural deposits is associated with iron oxides/oxyhydroxides, phases common in iron pipe corrosion by-products. The extent of potential reservoirs of V in iron corrosion by-products, its speciation, and mechanism of inclusion however are unknown. The aim of this study is to assess these parameters in iron corrosion by-products, implementing synchrotron-based μ-XRF mapping and μ-XANES along with traditional physiochemical characterization. The morphologies, mineralogies, and chemistry of the samples studied are superficially similar to typical iron corrosion by-products. However, we found V present as discrete grains of Pb(5)(V(5+)O(4))(3)Cl likely embedded in the surface regions of the iron corrosion by-products. Concentrations of V observed in bulk XRF analysis ranged from 35 to 899 mg kg(-1). We calculate that even in pipes with iron corrosion by-products with low V concentration, 100 mg kg(-1), as little as 0.0027% of a 0.1-cm thick X 100-cm long section of that corrosion by-product needs to be disturbed to increase V concentrations in the drinking water at the tap to levels well above the 15 μg L(-1) notification level set by the State of California and could adversely impact human health. In addition, it is likely that large reservoirs of V are associated with iron corrosion by-products in unlined cast iron mains and service branches in numerous drinking water distribution systems.

  6. Formation and Release Behavior of Iron Corrosion Products under the Influence of Bacterial Communities in a Simulated Water Distribution System

    EPA Science Inventory

    Understanding the effects of biofilm on the iron corrosion, iron release and associated corrosion by-products is critical for maintaining the water quality and the integrity of drinking water distribution system (DWDS). In this work, iron corrosion experiments under sterilized a...

  7. Formation and Release Behavior of Iron Corrosion Products under the Influence of Bacterial Communities in a Simulated Water Distribution System

    EPA Science Inventory

    Understanding the effects of biofilm on the iron corrosion, iron release and associated corrosion by-products is critical for maintaining the water quality and the integrity of drinking water distribution system (DWDS). In this work, iron corrosion experiments under sterilized a...

  8. Effect of natural and synthetic iron corrosion products on silicate glass alteration processes

    NASA Astrophysics Data System (ADS)

    Dillmann, Philippe; Gin, Stéphane; Neff, Delphine; Gentaz, Lucile; Rebiscoul, Diane

    2016-01-01

    Glass long term alteration in the context of high-level radioactive waste (HLW) storage is influenced by near-field materials and environmental context. As previous studies have shown, the extent of glass alteration is strongly related to the presence of iron in the system, mainly provided by the steel overpack around surrounding the HLW glass package. A key to understanding what will happen to the glass-borne elements in the geological disposal lies in the relationship between the iron-bearing phases and the glass alteration products formed. In this study, we focus on the influence of the formation conditions (synthetized or in-situ) and the age of different iron corrosion products on SON68 glass alteration. Corrosion products obtained from archaeological iron artifacts are considered here to be true analogues of the corrosion products in a waste disposal system due to the similarities in formation conditions and physical properties. These representative corrosion products (RCP) are used in the experiment along with synthetized iron anoxic corrosion products and pristine metallic iron. The model-cracks of SON68 glass were altered in cell reactors, with one of the different iron-sources inserted in the crack each time. The study was successful in reproducing most of the processes observed in the long term archaeological system. Between the different systems, alteration variations were noted both in nature and intensity, confirming the influence of the iron-source on glass alteration. Results seem to point to a lesser effect of long term iron corrosion products (RCP) on the glass alteration than that of the more recent products (SCP), both in terms of general glass alteration and of iron transport.

  9. Corrosion rate estimations of microscale zerovalent iron particles via direct hydrogen production measurements.

    PubMed

    Velimirovic, Milica; Carniato, Luca; Simons, Queenie; Schoups, Gerrit; Seuntjens, Piet; Bastiaens, Leen

    2014-04-15

    In this study, the aging behavior of microscale zerovalent iron (mZVI) particles was investigated by quantifying the hydrogen gas generated by anaerobic mZVI corrosion in batch degradation experiments. Granular iron and nanoscale zerovalent iron (nZVI) particles were included in this study as controls. Firstly, experiments in liquid medium (without aquifer material) were performed and revealed that mZVI particles have approximately a 10-30 times lower corrosion rate than nZVI particles. A good correlation was found between surface area normalized corrosion rate (RSA) and reaction rate constants (kSA) of PCE, TCE, cDCE and 1,1,1-TCA. Generally, particles with higher degradation rates also have faster corrosion rates, but exceptions do exists. In a second phase, the hydrogen evolution was also monitored during batch tests in the presence of aquifer material and real groundwater. A 4-9 times higher corrosion rate of mZVI particles was observed under the natural environment in comparison with the aquifer free artificial condition, which can be attributed to the low pH of the aquifer and its buffer capacity. A corrosion model was calibrated on the batch experiments to take into account the inhibitory effects of the corrosion products (dissolved iron, hydrogen and OH(-)) on the iron corrosion rate.

  10. Evaluation of Characterization Techniques for Iron Pipe Corrosion Products and Iron Oxide Thin Films

    SciTech Connect

    Borch, Thomas; Camper, Anne K.; Biederman, Joel A.; Butterfield, Phillip; Gerlach, Robin; Amonette, James E.

    2008-10-01

    A common problem faced by drinking water studies is that of properly characterizing the corrosion products (CP) in iron pipescor synthetic Fe (hydr)oxides used to simulate the iron pipe used in municipal drinking-water systems. The present work compares the relative applicability of a suite of imaging and analytical techniques for the characterization of CPs and synthetic Fe oxide thin films and provide an overview of the type of data that each instrument can provide as well as their limitations to help researchers and consultants choose the best technique for a given task. Crushed CP from a water distribution system and synthetic Fe oxide thin films formed on glass surfaces were chosen as test samples for this evaluation. The CP and synthetic Fe oxide thin films were analyzed by atomic force microscopy (AFM), scanning electron microscopy (SEM), energy-dispersive spectroscopy, time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray powder diffractometry (XRD), grazing incident diffractometry (GID), transmission electron microscopy (TEM), selected area electron diffraction, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared, Mössbauer spectroscopy, Brunauer-Emmett-Teller N2 adsorption and Fe concentration was determined by the ferrozine method. XRD and GID were found to be the most suitable techniques for identification of the mineralogical composition of CP and synthetic Fe oxide thin films, respectively. AFM and a combined ToF-SIMS-AFM approach proved excellent for roughness and depth profiling analysis of synthetic Fe oxide thin films, respectively. Corrosion products were difficult to study by AFM due to their surface roughness, while synthetic Fe oxide thin films resisted most spectroscopic methods due to their limited thickness (118 nm). XPS analysis is not recommended for mixtures of Fe (hydr)oxides due to their spectral similarities. SEM and TEM provided great detail on mineralogical morphology.

  11. The corrosion products of weathering steel and pure iron in simulated wet-dry cycles

    NASA Astrophysics Data System (ADS)

    Dávalos, J.; Marco, J. F.; Gracia, M.; Gancedo, J. R.

    1991-11-01

    Mössbauer spectroscopy and X-ray diffraction were used to establish the composition of the rust formed on pure iron and weathering steel after exposure to several wet-dry cycles in an SO2-polluted atmosphere. α-FeOOH poorly crystallized and quasi amorphous ferrihydrite are identified as the main corrosion products. The rust has different particle size for iron and weathering steel samples.

  12. Effect of corrosion products (neodymium iron boron) on oral fibroblast proliferation.

    PubMed

    Evans, R D; McDonald, F

    1995-01-01

    The biological effects of the corrosion products of neodymium iron boron (Nd2Fe14B) magnets are largely unknown. The aim of this study was to identify the types of corrosion product and to evaluate the effect of the corrosion products (CP) of Nd2Fe14B magnets on the proliferation of human oral mucosal fibroblasts. Uncoated Nd2Fe14B magnets were stored in saline at 37 degrees C for 6 months and the corrosion products collected. 100 microL of a cell suspension (human oral mucosal fibroblasts [14 x 10(4) cells/mL]) was aliquoted into 72 wells of a 96-well plate, the remaining plates receiving culture medium only. After 12 h incubation at 37 degrees C, each well then received 100 microL of either (A) culture medium, (B) 100% CP, (C) 50% CP, or (D) 0% CP. The plates were reincubated at 37 degrees C for a further 48, 96, or 144 h. Fibroblast proliferation was assessed using the methylene blue uptake/elution technique. The compounds in the corrosion product were examined using quantitative X-ray analysis. Statistical analysis (ANOVA, Bonferroni's test 0.05, SAS v 6.04), showed that at each time point, the cell numbers in groups B, C, and D were significantly lower than group A. Within groups B, C, and D no significant differences were found, despite the suggestion of a dose response effect. Fibroblast proliferation in the presence of corrosion products was significantly lower than with culture medium. Fibroblast proliferation did occur in the presence of 0, 50, and 100% CP. The actual corrosion products appeared to be salts of iron but 3.2% (+/- 0.6) of neodymium chloride (NdCl3) was found.

  13. Mini-review: the morphology, mineralogy and microbiology of accumulated iron corrosion products.

    PubMed

    Little, Brenda J; Gerke, Tammie L; Lee, Jason S

    2014-09-01

    Despite obvious differences in morphology, substratum chemistry and the electrolyte in which they form, accumulations of iron corrosion products have the following characteristics in common: stratification of iron oxides/hydroxides with a preponderance of α-FeOOH (goethite) and accumulation of metals. Bacteria, particularly iron-oxidizing and sulfate-reducing bacteria have been identified in some accumulations. Both biotic and abiotic mechanisms have been used to rationalize observations for particular sets of environmental data. This review is the first to compare observations and interpretations.

  14. Mini-review: the morphology, mineralogy and microbiology of accumulated iron corrosion products

    PubMed Central

    Little, Brenda J.; Gerke, Tammie L.; Lee, Jason S.

    2014-01-01

    Despite obvious differences in morphology, substratum chemistry and the electrolyte in which they form, accumulations of iron corrosion products have the following characteristics in common: stratification of iron oxides/hydroxides with a preponderance of α-FeOOH (goethite) and accumulation of metals. Bacteria, particularly iron-oxidizing and sulfate-reducing bacteria have been identified in some accumulations. Both biotic and abiotic mechanisms have been used to rationalize observations for particular sets of environmental data. This review is the first to compare observations and interpretations. PMID:25271874

  15. Formation and release behavior of iron corrosion products under the influence of bacterial communities in a simulated water distribution system.

    PubMed

    Sun, Huifang; Shi, Baoyou; Lytle, Darren A; Bai, Yaohui; Wang, Dongsheng

    2014-03-01

    To understand the formation and release behavior of iron corrosion products in a drinking water distribution system, annular reactors (ARs) were used to investigate the development processes of corrosion products and biofilm community as well as the concomitant iron release behavior. Results showed that the formation and transformation of corrosion products and bacterial community are closely related to each other. The presence of sulfate-reducing bacteria (SRB, e.g. Desulfovibrio and Desulfotomaculum), sulfur-oxidizing bacteria (SOB, e.g. Sulfuricella), and iron-oxidizing bacteria (IOB, e.g. Acidovorax, Gallionella, Leptothrix, and Sphaerotilus) in biofilms could speed up iron corrosion; however, iron-reducing bacteria (IRB, e.g. Bacillus, Clostridium, and Pseudomonas) could inhibit iron corrosion and iron release. Corrosion scales on iron coupons could develop into a two-layered structure (top layer and inner layer) with time. The relatively stable constituents such as goethite (α-FeOOH) and magnetite (Fe3O4) mainly existed in the top layers, while green rust (Fe6(OH)12CO3) mainly existed in the inner layers. The IOB (especially Acidovorax) contributed to the formation of α-FeOOH, while IRB and the anaerobic conditions could facilitate the formation of Fe3O4. Compared with the AR test without biofilms, the iron corrosion rate with biofilms was relatively higher (p < 0.05) during the whole experimental period, but the iron release with biofilms was obviously lower both at the initial stage and after 3 months. Biofilm and corrosion scale samples formed under different water supply conditions in an actual drinking water distribution system verified the relationships between the bacterial community and corrosion products.

  16. Corrosion of iron by iodide-oxidizing bacteria isolated from brine in an iodine production facility.

    PubMed

    Wakai, Satoshi; Ito, Kimio; Iino, Takao; Tomoe, Yasuyoshi; Mori, Koji; Harayama, Shigeaki

    2014-10-01

    Elemental iodine is produced in Japan from underground brine (fossil salt water). Carbon steel pipes in an iodine production facility at Chiba, Japan, for brine conveyance were found to corrode more rapidly than those in other facilities. The corroding activity of iodide-containing brine from the facility was examined by immersing carbon steel coupons in "native" and "filter-sterilized" brine samples. The dissolution of iron from the coupons immersed in native brine was threefold to fourfold higher than that in the filter-sterilized brine. Denaturing gradient gel electrophoresis analyses revealed that iodide-oxidizing bacteria (IOBs) were predominant in the coupon-containing native brine samples. IOBs were also detected in a corrosion deposit on the inner surface of a corroded pipe. These results strongly suggested the involvement of IOBs in the corrosion of the carbon steel pipes. Of the six bacterial strains isolated from a brine sample, four were capable of oxidizing iodide ion (I(-)) into molecular iodine (I(2)), and these strains were further phylogenetically classified into two groups. The iron-corroding activity of each of the isolates from the two groups was examined. Both strains corroded iron in the presence of potassium iodide in a concentration-dependent manner. This is the first report providing direct evidence that IOBs are involved in iron corrosion. Further, possible mechanisms by which IOBs corrode iron are discussed.

  17. Kinetics and corrosion products of aqueous nitrate reduction by iron powder without reaction conditions control.

    PubMed

    Fan, Xiaomeng; Guan, Xiaohong; Ma, Jun; Ai, Hengyu

    2009-01-01

    Although considerable research has been conducted on nitrate reduction by zero-valent iron powder (Fe0), these studies were mostly operated under anaerobic conditions with invariable pH that was unsuitable for practical application. Without reaction conditions (dissolved oxygen or reaction pH) control, this work aimed at subjecting the kinetics of denitrification by microscale Fe0 (160-200 mesh) to analysis the factors affecting the denitrification of nitrate and the composition of iron reductive products coating upon the iron surface. Results of the kinetics study have indicated that a higher initial concentration of nitrate would yield a greater reaction rate constant. The reduction rate of nitrate increased with increasing Fe0 dosage. The reaction can be described as a pseudo-first order reaction with respect to nitrate concentration or Fe0 dosage. Experimental results also suggested that nitrate reduction by microscale Fe0 without reaction condition control primarily was an acid-driven surface-mediated process, and the reaction order was 0.65 with respect to hydrogen ion concentration. The analyses of X-ray diffractometry and X-ray photoelectron spectroscopy indicated that a black coating, consisted of Fe2O3, Fe3O4 and FeO(OH), was formed on the surface of iron grains as an iron corrosion product when the system initial pH was lower than 5. The proportion of FeO(OH) increased as reaction time went on, whereas the proportion of Fe3O4 decreased.

  18. The Corrosion and Preservation of Iron Antiques.

    ERIC Educational Resources Information Center

    Walker, Robert

    1982-01-01

    Discusses general corrosion reactions (iron to rust), including corrosion of iron, sulfur dioxide, chlorides, immersed corrosion, and underground corrosion. Also discusses corrosion inhibition, including corrosion inhibitors (anodic, cathodic, mixed, organic); safe/dangerous inhibitors; and corrosion/inhibition in concrete/marble, showcases/boxes,…

  19. The Corrosion and Preservation of Iron Antiques.

    ERIC Educational Resources Information Center

    Walker, Robert

    1982-01-01

    Discusses general corrosion reactions (iron to rust), including corrosion of iron, sulfur dioxide, chlorides, immersed corrosion, and underground corrosion. Also discusses corrosion inhibition, including corrosion inhibitors (anodic, cathodic, mixed, organic); safe/dangerous inhibitors; and corrosion/inhibition in concrete/marble, showcases/boxes,…

  20. Anaerobic corrosion reaction kinetics of nanosized iron.

    PubMed

    Reardon, Eric J; Fagan, Randal; Vogan, John L; Przepiora, Andrzej

    2008-04-01

    Nanosized Fe0 exhibits markedly different anaerobic corrosion rates in water compared to that disseminated in moist quartz sand. In water, hydrogen production from corrosion exhibits an autocatalytic style, attaining a maximum rate of 1.9 mol kg(-1) d(-1) within 2 d of reaction. The rate then drops sharply over the next 20 d and enters a period of uniformly decreasing rate, represented equally well by first-order or diffusion-controlled kinetic expressions. In quartz sand, hydrogen production exhibits a double maximum over the first 20 d, similar to the hydration reaction of Portland cement, and the highest rate attained is less than 0.5 mol kg(-1) d(-1). We ascribe this difference in early time corrosion behavior to the ability of the released hydrogen gas to convect both water and iron particles in an iron/water system and to its inability to do so when the iron particles are disseminated in sand. By 30 d, the hydrogen production rate of iron in quartz sand exhibits a uniform decrease as in the iron/water system, which also can be described by first-order or diffusion-controlled kinetic expressions. However, the corrosion resistance of the iron in moist sand is 4 times greater than in pure water (viz. t1/2 of 365 d vs 78 d, respectively). The lower rate for iron in sand is likely due to the effect of dissolved silica sorbing onto iron reaction sites and acting as an anodic inhibitor, which reduces the iron's susceptibility to oxidation by water. This study indicates that short-term laboratory corrosion tests of nanosized Fe0/water slurries will substantially underestimate both the material's longevity as an electron source and its potential as a long-term source of hydrogen gas in groundwater remediation applications.

  1. Speciation And Distribution Of Vanadium In Drinking Water Iron Pipe Corrosion By-Products

    EPA Science Inventory

    Vanadium (V) when ingested from drinking water in high concentrations (> 15 µg L-1) is a potential health risk and is on track to becoming a regulated contaminant. High concentrations of V have been documented in lead corrosion by-products as Pb5(V5+

  2. Speciation And Distribution Of Vanadium In Drinking Water Iron Pipe Corrosion By-Products

    EPA Science Inventory

    Vanadium (V) when ingested from drinking water in high concentrations (> 15 µg L-1) is a potential health risk and is on track to becoming a regulated contaminant. High concentrations of V have been documented in lead corrosion by-products as Pb5(V5+

  3. Hibbingite(Beta-Fe2(OH)3Cl), a Chlorine-rich Corrosion Product in Meteorites and Ancient Iron Objects

    NASA Astrophysics Data System (ADS)

    Buchwald, V. F.; Koch, C. B.

    1995-09-01

    In a continuing survey over the corrosion of meteorites[1-3], the role of chlorine has in particular been examined. It has been shown that even under pristine antarctic conditions, akaganeite, the chlorine containing Beta-FeOOH will form[1,2], and that akaganeite is a common mineral in terrestrial corrosion also under temperate and sub-tropic conditions. Especially when an (iron) meteorite is transported from its soil environment to the laboratory or the museum, akaganeite formation may be violent and lead to destruction of the material. One way of improving the resistance to deterioration is to remove chlorine by exposing the sample to a hydrogen plasma[4]. Chlorine is present at a higher content, 18 wt%, in the compound Beta-Fe(sub)2(OH)(sub)3Cl. This compound was identified in the corroded parts of the iron meteorites Jerslev, Carbo, Odessa, Sardis, Toluca, Waverly, Willamette and Yamato 791694. The research was mainly carried out in The National Museum of Natural History, Washington, in 1988. The mineral is remarkable as being the only corrosion product that contains iron solely in the oxidation state II[1]. The mineral has later been identified in terrestrial rocks and it has been named hibbingite[5]. Hibbingite in iron meteorites occurs as thin films and as up to 1 x 0.1 mm veins and void-fillings. The mineral appears greenish under the microscope. It is softer than the iron matrix and adjacent goethite and magnetite, but it withstands routine preparation of sections and wet polishing operations. It is often associated with akaganeite, but is greenish as compared to the orangered color of akaganeite. Hibbingite belongs to a small group of hexagonal metalhydroxyhalogenides, Me(sub)2(OH)(sub)3X, where Me may be Cu(II), Co(II), Ni(II) and Fe(II), and X may be Cl, Br and I. In meteorites hibbingite is surprisingly pure -compared to e.g. akaganeite- since the lattice only accepts nickel (0-6 wt%) in substitution for iron. Hibbingite has also been identified by

  4. Corrosion of ductile iron piping

    SciTech Connect

    Szeliga, M.

    1995-12-31

    A compilation of 20 classic NACE papers on the subject, dating from 1957 to 1994. Papers include: Corrosion of Municipal Iron Watermains, Protecting Water Pipelines with Pipeline Coatings Conforming to American Water Works Association Coating Standards, Analysis of Aged Water Distribution Systems, and many more.

  5. Study of ferrous corrosion products on iron archaeological objects by electron backscattered diffraction (EBSD)

    NASA Astrophysics Data System (ADS)

    Azoulay, Ilanith; Conforto, Egle; Refait, Philippe; Rémazeilles, Céline

    2013-02-01

    The corrosion of iron-based archaeomaterials in anoxic environments leads mainly to Fe(II) compounds, like the hydroxychloride β-Fe2(OH)3Cl, chukanovite Fe2(OH)2CO3 or siderite FeCO3. The understanding of the mechanisms then necessarily implies a thorough investigation of the chemical, mechanical and morphological characteristics of the Fe(II)-based layer that develops between the metal surface and the environment. In the peculiar case of Fe(II) compounds, generally very reactive towards O2, the main concern is to prevent any transformation by air during the analysis. The EBSD technique is adapted on a scanning electron microscope (SEM) where the samples are analysed under vacuum and consequently sheltered from air. Different options offered by EBSD for phase characterisation and microstructural study were tested for the first time on the rust layers of two archaeological iron nails. Results were confronted to those obtained by micro-Raman spectroscopy, which was used as reference method. Magnetite, Fe(II) hydroxychloride β-Fe2(OH)3Cl and siderite were analysed successfully but improvements have to be brought for the study of other compounds such as iron oxyhydroxides and chukanovite. The choice of experimental parameters in our approach as well as the potentialities and limits of the technique for this kind of application are discussed.

  6. Effects of humic acid on arsenic(V) removal by zero-valent iron from groundwater with special references to corrosion products analyses.

    PubMed

    Rao, Pinhua; Mak, Mark S H; Liu, Tongzhou; Lai, Keith C K; Lo, Irene M C

    2009-04-01

    The effects of humic acid (HA) on As(V) removal by zero-valent iron (Fe(0)) from groundwater, associated with corrosion products analyses, were investigated using batch experiments. It was found that arsenic was rapidly removed from groundwater possibly due to its adsorption and co-precipitation with the corrosion products of Fe(0). The removal rate of arsenic by Fe(0) was inhibited in the presence of HA probably because of the formation of soluble Fe-humate in groundwater which hindered the production of iron precipitates. A longer reaction time was then required for arsenic removal. Such an influence of HA on arsenic removal increased with increasing HA concentration from 5 to 25mgL(-1). The binding capacity of HA for dissolved Fe was estimated to be about 0.75mg Femg(-1) HA. When the complexation of HA with dissolved Fe was saturated, further corrosion of Fe(0) would produce precipitates, which significantly accelerated the removal of arsenic from groundwater via adsorption and co-precipitation with the corrosion products. Iron (hydr)oxides such as maghemite, lepidocrocite, and magnetite were characterized by XRD analyses as the corrosion products, while As(V) was found on the surface of these corrosion products as detected by fourier transform infrared spectrometry and X-ray photoelectron spectroscopy.

  7. Effects of microbial redox cycling of iron on cast iron pipe corrosion in drinking water distribution systems.

    PubMed

    Wang, Haibo; Hu, Chun; Zhang, Lili; Li, Xiaoxiao; Zhang, Yu; Yang, Min

    2014-11-15

    Bacterial characteristics in corrosion products and their effect on the formation of dense corrosion scales on cast iron coupons were studied in drinking water, with sterile water acting as a reference. The corrosion process and corrosion scales were characterized by electrochemical and physico-chemical measurements. The results indicated that the corrosion was more rapidly inhibited and iron release was lower due to formation of more dense protective corrosion scales in drinking water than in sterile water. The microbial community and denitrifying functional genes were analyzed by pyrosequencing and quantitative polymerase chain reactions (qPCR), respectively. Principal component analysis (PCA) showed that the bacteria in corrosion products played an important role in the corrosion process in drinking water. Nitrate-reducing bacteria (NRB) Acidovorax and Hydrogenophaga enhanced iron corrosion before 6 days. After 20 days, the dominant bacteria became NRB Dechloromonas (40.08%) with the protective corrosion layer formation. The Dechloromonas exhibited the stronger corrosion inhibition by inducing the redox cycling of iron, to enhance the precipitation of iron oxides and formation of Fe3O4. Subsequently, other minor bacteria appeared in the corrosion scales, including iron-respiring bacteria and Rhizobium which captured iron by the produced siderophores, having a weaker corrosion-inhibition effect. Therefore, the microbially-driven redox cycling of iron with associated microbial capture of iron caused more compact corrosion scales formation and lower iron release.

  8. Sorption of Th(IV) onto iron corrosion products: EXAFS study.

    PubMed

    Seco, Ferran; Hennig, Christoph; de Pablo, Joan; Rovira, Miquel; Rojo, Isabel; Martí, Vicens; Giménez, Javier; Duro, Lara; Grivé, Mireia; Bruno, Jordi

    2009-04-15

    Long-term performance assessment of nuclear waste repositories is affected by the ability of the outer barrier systems to retain radionuclides after possible corrosive leakage of waste containers. The mobility of the radionuclides released from the spent fuel depends strongly on the processes that take place in the backfill material. The interaction of steel corrosion products and radionuclides is part of such a scenario. In this work, the sorption of Th(IV) onto 2-line-ferrihydrite (FeOOH x H2O) and magnetite (Fe3O4), used as models for steel corrosion products, has been studied using EXAFS spectroscopy. Sorption samples were prepared in 0.1 M NaClO4 solutions at acidic pH (initial pH values in the range 3.0-4.2) either from undersaturation and supersaturation conditions with respect to amorphous ThO2. Two oxygen subshells, one at 2.37 A and another at 2.54 A, were observed in the first hydration sphere of Th in the case of the ferrihydrite samples. Th-Fe distances for the different ferrihydrite samples are approximately 3.60 A. These results indicate a corner sharing surface complex of Th(IV) ion onto the ferrihydrite surface where the Th atom shares one O atom with each of two coordinated octahedra. The longer Th-O distance accounts for coordinated water molecules. No significant changes in the structural environment of Th in terms of coordination numbers and distances were detected as a function of Th(IV) concentration. Magnetite samples sorbing Th(IV) also showed also a strong distortion of the O shell, but in contrast to ferrihydrite, two types of nearest Fe atoms were detected at 3.50 A and 3.70 A. These results indicate that Th(IV) ion sorbs onto the magnetite surface as bidentate-corner sharing arrangements to [FeO6] octahedra and [FeO4] tetrahedra.

  9. Corrosion performance of iron aluminides

    SciTech Connect

    Natesan, K.

    1993-03-01

    Iron aluminides are being developed for use as structural materials and/or cladding alloys in fossil energy systems. Extensive development has been in progress on Fe{sub 3}Al-based alloys to improve the engineering ductility of these alloys. This paper describes results from the ongoing program to evaluate the corrosion performance of these alloys. The experimental program at Argonne National Laboratory involvesthermogravimetric analyses of alloys exposed to environments that simulate coal gasification and fluidized-bed combustion. Experiments were conducted at 650--1000{degrees}C in simulated oxygen/sulfur gas mixtures. In addition, oxidation/sulfidation behavior of several alumina-forming Fe-Al and Fe-Cr-Ni-Al alloys was determined for comparison with the corrosion rates obtained on iron aluminides. Other aspects of the program are corrosion evaluation of the aluminides in the presence of HC1-containing gases and in the presence of slag from a slogging gasifier. Results are used to establish threshold Al levels in the alloys for development of protective alumina scales. Thermal cycling tests are used to examine the spalling resistance of the scales.

  10. Corrosion performance of iron aluminides

    SciTech Connect

    Natesan, K.

    1993-03-01

    Iron aluminides are being developed for use as structural materials and/or cladding alloys in fossil energy systems. Extensive development has been in progress on Fe[sub 3]Al-based alloys to improve the engineering ductility of these alloys. This paper describes results from the ongoing program to evaluate the corrosion performance of these alloys. The experimental program at Argonne National Laboratory involvesthermogravimetric analyses of alloys exposed to environments that simulate coal gasification and fluidized-bed combustion. Experiments were conducted at 650--1000[degrees]C in simulated oxygen/sulfur gas mixtures. In addition, oxidation/sulfidation behavior of several alumina-forming Fe-Al and Fe-Cr-Ni-Al alloys was determined for comparison with the corrosion rates obtained on iron aluminides. Other aspects of the program are corrosion evaluation of the aluminides in the presence of HC1-containing gases and in the presence of slag from a slogging gasifier. Results are used to establish threshold Al levels in the alloys for development of protective alumina scales. Thermal cycling tests are used to examine the spalling resistance of the scales.

  11. Mini-review: The Morphology, Mineralogy and Microbiology of Accumulated Iron Corrosion Products

    DTIC Science & Technology

    2014-03-11

    environmental scanning electron microscopy coupled with energy dispersive X-ray spectrometry and powder X-ray diffraction (XRD) to examine rusticles from... powder XRD, they reported that rusticles on wrought iron surfaces of the USS Monitor had an outer casing of FeCO3, γ-FeOOH and α-FeOOH. They described...invertebrates, reef fish Gulfpenn 554 1921–1942 Tanker 90 k barrels gasoline Some microbial concretions ; abundant Lophelia pertusa, high invertebrate

  12. Interaction of sulfuric acid corrosion and mechanical wear of iron

    NASA Technical Reports Server (NTRS)

    Rengstorff, G. W. P.; Miyoshi, K.; Buckley, D. H.

    1986-01-01

    Friction and wear experiment were conducted with elemental iron sliding on aluminum oxide in aerated sulfuric acid at concentrations ranging from very dilute (0.00007 N; i.e., 4 ppm) to very concentrated (96 percent acid). Load and reciprocating sliding speed were kept constant. With the most dilute acid concentration of 0.00007 to 0.0002 N, a complex corrosion product formed that was friable and often increased friction and wear. At slightly higher concentrations of 0.001 N, metal losses were essentially by wear alone. Because no buildup of corrosion products occurred, this acid concentration became the standard from which to separate metal loss from direct corrosion and mechanical wear losses. When the acid concentration was increased to 5 percent (1 N), the well-established high corrosion rate of iron in sulfuric acid strongly dominated the total wear loss. This strong corrosion increased to 30 percent acid and decreased somewhat to 50 percent acid in accordance with expectations. However, the low corrosion of iron expected at acid concentrations of 65 to 96 percent was not observed in the wear area. It was apparent that the normal passivating film was being worn away and a galvanic cell established that rapidly attacked the wear area. Under the conditions where direct corrosion losses were highest, the coefficient of friction was the lowest.

  13. Interaction of sulfuric acid corrosion and mechanical wear of iron

    NASA Technical Reports Server (NTRS)

    Rengstorff, G. W. P.; Miyoshi, K.; Buckley, D. H.

    1984-01-01

    Friction and wear experiments were conducted with elemental iron sliding on aluminum oxide in aerated sulfuric acid at concentrations ranging from very dilute (0.00007 N; i.e., 4 ppm) to very concentrated (96 percent acid). Load and reciprocating sliding speed were kept constant. With the most dilute acid concentration of 0.00007 to 0.0002 N, a complex corrosion product formed that was friable and often increased friction and wear. At slightly higher concentrations of 0.001 N, metal losses were essentially by wear alone. Because no buildup of corrosion products occurred, this acid concentration became the standard from which to separate metal loss from direct corrosion and mechanical wear losses. When the acid concentration was increased to 5 percent (1 N), the well-established high corrosion rate of iron in sulfuric acid strongly dominated the total wear loss. This strong corrosion increased to 30 percent acid and decreased somewhat to 50 percent acid in accordance with expectations. However, the low corrosion of iron expected at acid concentrations of 65 to 96 percent was not observed in the wear area. It was apparent that the normal passivating film was being worn away and a galvanic cell established that rapidly attacked the wear area. Under the conditions where direct corrosion losses were highest, the coefficient of friction was the lowest.

  14. Formation of ferrihydrite and associated iron corrosion products in permeable reactive barriers of zero-valent iron

    NASA Technical Reports Server (NTRS)

    Furukawa, Yoko; Kim, Jin-Wook; Watkins, Janet; Wilkin, Richard T.

    2002-01-01

    Ferrihydrite, which is known to form in the presence of oxygen and to be stabilized by the adsorption of Si, PO4 and SO4, is ubiquitous in the fine-grained fractions of permeable reactive barrier (PRB) samples from the U.S. Coast Guard Support Center (Elizabeth City, NC) and the Denver Federal Center (Lakewood, CO) studied by high-resolution transmission electron microscopy and selected area electron diffraction. The concurrent energy-dispersive X-ray data indicate a strong association between ferrihydrite and metals such as Si, Ca, and Cr. Magnetite, green rust 1, aragonite, calcite, mackinawite, greigite and lepidocrocite were also present, indicative of a geochemical environment that is temporally and spatially heterogeneous. Whereas magnetite, which is known to form due to anaerobic Fe0 corrosion, passivates the Fe0 surface, ferrihydrite precipitation occurs away from the immediate Fe0 surface, forming small (<0.1 microm) discrete clusters. Consequently, Fe0-PRBs may remain effective for a longer period of time in slightly oxidized groundwater systems where ferrihydrite formation occurs compared to oxygen-depleted systems where magnetite passivation occurs. The ubiquitous presence of ferrihydrite suggests that the use of Fe0-PRBs may be extended to applications that require contaminant adsorption rather than, or in addition to, redox-promoted contaminant degradation.

  15. Formation of ferrihydrite and associated iron corrosion products in permeable reactive barriers of zero-valent iron

    NASA Technical Reports Server (NTRS)

    Furukawa, Yoko; Kim, Jin-Wook; Watkins, Janet; Wilkin, Richard T.

    2002-01-01

    Ferrihydrite, which is known to form in the presence of oxygen and to be stabilized by the adsorption of Si, PO4 and SO4, is ubiquitous in the fine-grained fractions of permeable reactive barrier (PRB) samples from the U.S. Coast Guard Support Center (Elizabeth City, NC) and the Denver Federal Center (Lakewood, CO) studied by high-resolution transmission electron microscopy and selected area electron diffraction. The concurrent energy-dispersive X-ray data indicate a strong association between ferrihydrite and metals such as Si, Ca, and Cr. Magnetite, green rust 1, aragonite, calcite, mackinawite, greigite and lepidocrocite were also present, indicative of a geochemical environment that is temporally and spatially heterogeneous. Whereas magnetite, which is known to form due to anaerobic Fe0 corrosion, passivates the Fe0 surface, ferrihydrite precipitation occurs away from the immediate Fe0 surface, forming small (<0.1 microm) discrete clusters. Consequently, Fe0-PRBs may remain effective for a longer period of time in slightly oxidized groundwater systems where ferrihydrite formation occurs compared to oxygen-depleted systems where magnetite passivation occurs. The ubiquitous presence of ferrihydrite suggests that the use of Fe0-PRBs may be extended to applications that require contaminant adsorption rather than, or in addition to, redox-promoted contaminant degradation.

  16. Reductive removal of selenate by zero-valent iron: The roles of aqueous Fe(2+) and corrosion products, and selenate removal mechanisms.

    PubMed

    Tang, Cilai; Huang, Yong H; Zeng, Hui; Zhang, Zengqiang

    2014-12-15

    Batch tests were conducted to investigate the roles of dissolved Fe(2+) and corrosion products, and the involved mechanisms in selenate (Se(VI)) removal by zero-valent iron (ZVI). The results showed that insignificant Se(VI) removal (4-7.5%) was observed in the presence of ZVI or Fe(2+) alone. However, external supply of dissolved ferrous ion dramatically enhanced Se(VI) removal in the presence of ZVI. Selenate removal efficiency increased with increasing Fe(2+) concentration. Selenate removal sustained only if Fe(2+) was supplied continuously. Both sequential extraction experiments and XPS analysis showed that selenate was reduced step by step, with elemental selenium and adsorbed selenite as the dominant reductive products. Selenite and elemental selenium could be further reduced to selenide, with continuous Fe(2+) supply and sufficient reaction time. In the ZVI-Se(VI)-Fe(2+) system, ZVI was the major electron donor for selenate reduction. Fe(2+) functioned as electron donor as well and was consumed with a Fe(2+):Se stoichiometry of ∼1:1. It also facilitated the transformation of the passive layer of iron coatings to a medium (e.g., magnetite) favoring electron transfer and thus enhanced selenate reduction. Iron corrosion products were media for electron transfer and reactive interfaces for selenium adsorption and reduction. These findings provided a new approach to overcome ZVI surface passivation for long-term application.

  17. Reactivity of Tannic Acid with Common Corrosion Products and Its Influence on the Hydrolysis of Iron in Alkaline Solutions

    NASA Astrophysics Data System (ADS)

    Jaén, J. A.; Araúz, E. Y.; Iglesias, J.; Delgado, Y.

    2003-06-01

    To ascertain the role of tannic acid in the anticorrosive protection of steels, the reaction between 5% tannic acid aqueous solutions with lepidocrocite, goethite, superparamagnetic goethite, akaganeite, poorly crystalline maghemite, magnetite and hematite was studied using color changes, infrared and Mössbauer spectroscopy. After three months of interaction with lepidocrocite, the formation of an iron tannate complex was detected by its dark blue color and confirmed by infrared and Mössbauer analysis. Evidence for the chemical transformation was obtained for goethite in nanoparticles and poorly crystalline maghemite after reaction for six months. The other iron compounds do not transform to another oxide or phase upon treatment with the tannic acid solution. These results showed that lepidocrocite is the most reactive phase and that the size and degree of crystallinity have strong influence on the formation of the tannate complexes. The precipitation of iron phases from alkaline solutions of iron (II) sulfate heptahydrate containing different amount of tannic acid and potassium nitrate as oxidative agent was also studied. Mössbauer and infrared results show that in the absence of tannic acid some common rust components are obtained (viz. goethite, superparamagnetic goethite, maghemite and non-stoichiometric magnetite). The presence of 0.1% tannic acid in a low alkalinity solution results in the precipitation of iron oxyhydroxides and some iron tannates. Concentrations of 1% tannic acid are required for the formation of the tannates complexes as main reaction product.

  18. High-temperature corrosion of iron aluminides

    SciTech Connect

    Natesan, K.; Cho, W.D.

    1994-04-01

    Iron aluminides are being developed for use as structural materials and/or cladding alloys in fossil energy systems. Extensive development has been in progress on Fe{sub 3}Al-based alloys to improve their engineering ductility. This paper describes results from an ongoing program to evaluate the corrosion performance of these alloys. The experimental program at Argonne involves thermogravimetric analyses of alloys exposed to environments that simulate coal gasification and coal combustion. Corrosion experiments were conducted to determine the effect of gas flow rate and different levels of HCl at a gas temperature of 650 C on three heats of aluminide material, namely, FA 61, FA 129, and FAX. In addition, specimens of Type 316 stainless steel with an overlay alloying of iron aluminide were prepared by electrospark deposition and tested for their corrosion resistance. Detailed microstructural evaluations of tested specimens were performed. Results are used to assess the corrosion resistance of various iron aluminides for service in fossil energy systems that utilize coal as a feedstock.

  19. Corrosion of iron by sulfate-reducing bacteria: new views of an old problem.

    PubMed

    Enning, Dennis; Garrelfs, Julia

    2014-02-01

    About a century ago, researchers first recognized a connection between the activity of environmental microorganisms and cases of anaerobic iron corrosion. Since then, such microbially influenced corrosion (MIC) has gained prominence and its technical and economic implications are now widely recognized. Under anoxic conditions (e.g., in oil and gas pipelines), sulfate-reducing bacteria (SRB) are commonly considered the main culprits of MIC. This perception largely stems from three recurrent observations. First, anoxic sulfate-rich environments (e.g., anoxic seawater) are particularly corrosive. Second, SRB and their characteristic corrosion product iron sulfide are ubiquitously associated with anaerobic corrosion damage, and third, no other physiological group produces comparably severe corrosion damage in laboratory-grown pure cultures. However, there remain many open questions as to the underlying mechanisms and their relative contributions to corrosion. On the one hand, SRB damage iron constructions indirectly through a corrosive chemical agent, hydrogen sulfide, formed by the organisms as a dissimilatory product from sulfate reduction with organic compounds or hydrogen ("chemical microbially influenced corrosion"; CMIC). On the other hand, certain SRB can also attack iron via withdrawal of electrons ("electrical microbially influenced corrosion"; EMIC), viz., directly by metabolic coupling. Corrosion of iron by SRB is typically associated with the formation of iron sulfides (FeS) which, paradoxically, may reduce corrosion in some cases while they increase it in others. This brief review traces the historical twists in the perception of SRB-induced corrosion, considering the presently most plausible explanations as well as possible early misconceptions in the understanding of severe corrosion in anoxic, sulfate-rich environments.

  20. IN DRIFT CORROSION PRODUCTS

    SciTech Connect

    D.M. Jolley

    1999-12-02

    As directed by a written development plan (CRWMS M&O 1999a), a conceptual model for steel and corrosion products in the engineered barrier system (EBS) is to be developed. The purpose of this conceptual model is to assist Performance Assessment Operations (PAO) and its Engineered Barrier Performance Department in modeling the geochemical environment within a repository drift, thus allowing PAO to provide a more detailed and complete in-drift geochemical model abstraction and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near-Field Environment (NFE) Revision 2 (NRC 1999). This document provides the conceptual framework for the in-drift corrosion products sub-model to be used in subsequent PAO analyses including the EBS physical and chemical model abstraction effort. This model has been developed to serve as a basis for the in-drift geochemical analyses performed by PAO. However, the concepts discussed within this report may also apply to some near and far-field geochemical processes and may have conceptual application within the unsaturated zone (UZ) and saturated zone (SZ) transport modeling efforts.

  1. Static Corrosion Test of Porous Iron Material with Polymer Coating

    NASA Astrophysics Data System (ADS)

    Markušová-Bučková, Lucia; Oriňaková, Renáta; Oriňak, Andrej; Gorejová, Radka; Kupková, Miriam; Hrubovčáková, Monika; Baláž, Matej; Kováľ, Karol

    2016-12-01

    At present biodegradable implants received increased attention due to their use in various fields of medicine. This work is dedicated to testing of biodegradable materials which could be used as bone implants. The samples were prepared from the carbonyl iron powder by replication method and surface polymer film was produced through sol-gel process. Corrosion testing was carried out under static conditions during 12 weeks in Hank's solution. The quantity of corrosion products increased with prolonging time of static test as it can be concluded from the results of EDX analysis. The degradation of open cell materials with polyethylene glycol coating layer was faster compared to uncoated Fe sample. Also the mass losses were higher for samples with PEG coating. The polymer coating brought about the desired increase in degradation rate of porous iron material.

  2. The role of iron in sulfide induced corrosion of sewer concrete.

    PubMed

    Jiang, Guangming; Wightman, Elaine; Donose, Bogdan C; Yuan, Zhiguo; Bond, Philip L; Keller, Jurg

    2014-02-01

    The sulfide-induced corrosion of concrete sewer is a widespread and expensive problem for water utilities worldwide. Fundamental knowledge of the initiation and propagation of sewer corrosion, especially the interactions between chemical reactions and physical structure changes, is still largely unknown. Advanced mineral analytical techniques were applied to identify the distribution of corrosion products and the micro-cracking that developed along the corrosion boundary. It was found that sewer concrete corrosion caused by reactions with sulfuric acid progressed uniformly in the cement of concrete. In contrast to conventional knowledge, iron rust rather than gypsum and ettringite was likely the factor responsible for cracking ahead of the corrosion front. The analysis also allowed quantitative determination of the major corrosion products, i.e., gypsum and ettringite, with the latter found closer to the corrosion front. The conceptual model based on these findings clearly demonstrated the complex interactions among different chemical reactions, diffusion, and micro-structure changes.

  3. Corrosion of Iron by Sulfate-Reducing Bacteria: New Views of an Old Problem

    PubMed Central

    Garrelfs, Julia

    2014-01-01

    About a century ago, researchers first recognized a connection between the activity of environmental microorganisms and cases of anaerobic iron corrosion. Since then, such microbially influenced corrosion (MIC) has gained prominence and its technical and economic implications are now widely recognized. Under anoxic conditions (e.g., in oil and gas pipelines), sulfate-reducing bacteria (SRB) are commonly considered the main culprits of MIC. This perception largely stems from three recurrent observations. First, anoxic sulfate-rich environments (e.g., anoxic seawater) are particularly corrosive. Second, SRB and their characteristic corrosion product iron sulfide are ubiquitously associated with anaerobic corrosion damage, and third, no other physiological group produces comparably severe corrosion damage in laboratory-grown pure cultures. However, there remain many open questions as to the underlying mechanisms and their relative contributions to corrosion. On the one hand, SRB damage iron constructions indirectly through a corrosive chemical agent, hydrogen sulfide, formed by the organisms as a dissimilatory product from sulfate reduction with organic compounds or hydrogen (“chemical microbially influenced corrosion”; CMIC). On the other hand, certain SRB can also attack iron via withdrawal of electrons (“electrical microbially influenced corrosion”; EMIC), viz., directly by metabolic coupling. Corrosion of iron by SRB is typically associated with the formation of iron sulfides (FeS) which, paradoxically, may reduce corrosion in some cases while they increase it in others. This brief review traces the historical twists in the perception of SRB-induced corrosion, considering the presently most plausible explanations as well as possible early misconceptions in the understanding of severe corrosion in anoxic, sulfate-rich environments. PMID:24317078

  4. Profiling iron corrosion coating on iron grains in a zerovalent iron system under the influence of dissolved oxygen.

    PubMed

    Zhang, Tian C; Huang, Yong H

    2006-07-01

    Rapid oxidation of Fe(0) by O(2) occurred when Fe(0) grains were bathed in 0.54 mM FeCl(2) solution saturated with dissolved oxygen (DO), forming a substantial corrosion coating on Fe(0) grains. A sonication method was developed to strip the corrosion coating off the iron grains layer by layer. The transformation of the constituents and the morphology of the corrosion coating along its depth and over reaction time were investigated with composition analysis, X-ray diffraction and scanning electron microscopy. Results indicate that the sonication method could consistently recover >90% iron oxides produced by the Fe(0)-DO redox reaction. Magnetite (Fe(3)O(4)) and lepidocrocite (gamma-FeOOH) were identified as the corrosion products. Initially, lepidocrocite was the preferential product in the presence of DO. As the oxide coating thickened, the inner layer transformed to magnetite, which retained as the only stable corrosion product once DO was depleted. The study confirms the phase transformations between gamma-FeOOH and Fe(3)O(4) within a stratified corrosion coating. The sonication technique exemplifies a new approach for investigating more complicated processes in Fe(0)/oxides/contaminants systems.

  5. Development of an Escherichia coli K12-specific quantitative polymerase chain reaction assay and DNA isolation suited to biofilms associated with iron drinking water pipe corrosion products.

    PubMed

    Lu, Jingrang; Gerke, Tammie L; Buse, Helen Y; Ashbolt, Nicholas J

    2014-12-01

    A quantitative polymerase chain reaction assay (115 bp amplicon) specific to Escherichia coli K12 with an ABI(TM) internal control was developed based on sequence data encoding the rfb gene cluster. Assay specificity was evaluated using three E. coli K12 strains (ATCC W3110, MG1655 & DH1), 24 non-K12 E. coli and 23 bacterial genera. The biofilm detection limit was 10(3) colony-forming units (CFU) E. coli K12 mL(-1), but required a modified protocol, which included a bio-blocker Pseudomonas aeruginosa with ethylenediaminetetraacetic acid buffered to pH 5 prior to cell lysis/DNA extraction. The novel protocol yielded the same sensitivity for drinking water biofilms associated with Fe3O4 (magnetite)-coated SiO2 (quartz) grains and biofilm-surface iron corrosion products from a drinking water distribution system. The novel DNA extraction protocol and specific E. coli K12 assay are sensitive and robust enough for detection and quantification within iron drinking water pipe biofilms, and are particularly well suited for studying enteric bacterial interactions within biofilms.

  6. Microbial Iron Respiration Can Protect Steel from Corrosion

    PubMed Central

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

    2002-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  8. Effects of chloride ions on corrosion of ductile iron and carbon steel in soil environments.

    PubMed

    Song, Yarong; Jiang, Guangming; Chen, Ying; Zhao, Peng; Tian, Yimei

    2017-07-31

    Chloride is reported to play a significant role in corrosion reactions, products and kinetics of ferrous metals. To enhance the understanding of the effects of soil environments, especially the saline soils with high levels of chloride, on the corrosion of ductile iron and carbon steel, a 3-month corrosion test was carried out by exposing ferrous metals to soils of six chloride concentrations. The surface morphology, rust compositions and corrosion kinetics were comprehensively studied by visual observation, scanning electron microscopy (SEM), X-Ray diffraction (XRD), weight loss, pit depth measurement, linear polarization and electrochemical impedance spectroscopy (EIS) measurements. It showed that chloride ions influenced the characteristics and compositions of rust layers by diverting and participating in corrosion reactions. α-FeOOH, γ-FeOOH and iron oxides were major corrosion products, while β-Fe8O8(OH)8Cl1.35 rather than β-FeOOH was formed when high chloride concentrations were provided. Chloride also suppressed the decreasing of corrosion rates, whereas increased the difficulty in the diffusion process by thickening the rust layers and transforming the rust compositions. Carbon steel is more susceptible to chloride attacks than ductile iron. The corrosion kinetics of ductile iron and carbon steel corresponded with the probabilistic and bilinear model respectively.

  9. Oxidant production from corrosion of nano- and microparticulate zero-valent iron in the presence of oxygen: a comparative study.

    PubMed

    Lee, Hongshin; Lee, Hye-Jin; Kim, Hyung-Eun; Kweon, Jihyang; Lee, Byeong-Dae; Lee, Changha

    2014-01-30

    In aqueous solution, zero-valent iron (ZVI, Fe(0)) is known to activate oxygen (O2) into reactive oxidants such as hydroxyl radical and ferryl ion capable of oxidizing contaminants. However, little is known about the effect of the particle size of ZVI on the yield of reactive oxidants. In this study, the production of reactive oxidants from nanoparticulate and microparticulate ZVIs (denoted as nZVI and mZVI, respectively) was comparatively investigated in the presence of O2 and EDTA. To quantify the oxidant yield, excess amount of methanol was employed, and the formation of its oxidation product, formaldehyde (HCHO), was monitored. The concentration of HCHO in the nZVI/O2 system rapidly reached the saturation value, whereas that in the mZVI/O2 system gradually increased throughout the entire reaction time. The mZVI/O2 system exhibited higher yields of HCHO than the nZVI/O2 system under both acidic and neutral pH conditions. The higher oxidant yields in the mZVI/O2 system are mainly attributed to the less reactivity of the mZVI surface with hydrogen peroxide (H2O2) relative to the surface of nZVI, which minimize the loss of H2O2 by ZVI (i.e., the two-electron reduction of H2O2 into water). In addition, the slow dissolution of Fe(II) from mZVI was found to be partially responsible for the higher oxidant yields at neutral pH.

  10. The rate of iron corrosion for different organic carbon sources during biofilm formation.

    PubMed

    Park, S K; Choi, S C; Kim, Y K

    2007-01-01

    The effects of total organic carbon and biofilm on microbial corrosion were quantified using serum bottles in a 2 x 2 factorial design. Both organic carbon and biofilm bacteria had a significant effect on the iron corrosion rate, irrespective of the levels of the other variable (p = 0.05). There was no evidence of interaction between organic carbon and biofilm bacteria. Within the tested levels, the addition of exogenous organic carbon increased the corrosion rate by an average of 3.838 mg dm(-2) day(-1) (mdd), but the presence of biofilm bacteria decreased the rate by an average of 2.305 mdd. More iron was released from the coupon in response to organic carbon. Powder x-ray diffractometry indicated that the scales deposited on the corroded iron surface consisted primarily of lepidocrocite (gamma-FeOOH), magnetite (Fe3O4) and hematite (alpha-Fe203). Corrosion rates by different organic carbon sources, i.e. acetate, glucose and humic substances, were compared using an annular biofilm reactor. One-way ANOVA suggested that the effect of each carbon source on corrosion was not the same, with the iron corrosion rate highest for glucose, followed by acetate, humic substances and the control. Magnetite was a major constituent of the corrosion products scraped from iron slides. Examination of community-level physiological profile patterns on the biofilms indicated that acetate was a carbon source that could promote the metabolic and functional potentials of biofilm communities.

  11. Effects of disinfectant and biofilm on the corrosion of cast iron pipes in a reclaimed water distribution system.

    PubMed

    Wang, Haibo; Hu, Chun; Hu, Xuexiang; Yang, Min; Qu, Jiuhui

    2012-03-15

    The effects of disinfection and biofilm on the corrosion of cast iron pipe in a model reclaimed water distribution system were studied using annular reactors (ARs). The corrosion scales formed under different conditions were characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM), while the bacterial characteristics of biofilm on the surface were determined using several molecular methods. The corrosion scales from the ARs with chlorine included predominantly α-FeOOH and Fe2O3, while CaPO3(OH)·2H2O and α-FeOOH were the predominant phases after chloramines replaced chlorine. Studies of the consumption of chlorine and iron release indicated that the formation of dense oxide layers and biofilm inhibited iron corrosion, causing stable lower chlorine decay. It was verified that iron-oxidizing bacteria (IOB) such as Sediminibacterium sp., and iron-reducing bacteria (IRB) such as Shewanella sp., synergistically interacted with the corrosion product to prevent further corrosion. For the ARs without disinfection, α-FeOOH was the predominant phase at the primary stage, while CaCO3 and α-FeOOH were predominant with increasing time. The mixed corrosion-inducing bacteria, including the IRB Shewanella sp., the IOB Sediminibacterium sp., and the sulfur-oxidizing bacteria (SOB) Limnobacter thioxidans strain, promoted iron corrosion by synergistic interactions in the primary period, while anaerobic IRB became the predominant corrosion bacteria, preventing further corrosion via the formation of protective layers.

  12. Influence of compositional modifications on the corrosion of iron aluminides of molten nitrate salts

    SciTech Connect

    Tortorelli, P.F.; Bishop, P.S.

    1991-01-01

    The corrosion of iron-aluminum alloys by molten nitrate salt as a function of aluminum, chromium, and other minor elements has been studied as part of an alloy design effort aimed at the development of a strong, ductile, corrosion-resistant FeAl type of aluminide. Short- term weight change data were used to examine the compositional dependence of the corrosion processes that occurred upon exposure of iron aluminides to highly oxidizing nitrate salts of 650{degrees}C. Corrosion resistance was found to increase with increasing aluminum concentrations of the alloy up to approximately 30 at. % Al. Chromium additions to the aluminide were not detrimental and may have improved the corrosion behavior for certain aluminum concentrations. No effects of minor alloying additions (C, B, Ti, and Zr) could be determined. The best overall corrosion resistance as measured by weight change results were obtained for an Fe-35.8 at. % Al aluminide containing some chromium. Based on linear weight loss kinetics, the weight change measurements for the most resistant compositions predict corrosion rates of 300 {mu}m/year or less at 650{degrees}C. These rates are substantially better than typical nickel-based alloys and stainless steels. From a consideration of the weight changes; the microstructural, thermodynamic, and X-ray diffraction data; and the salt analyses, corrosion of iron aluminides by the molten nitrate salt appears to be controlled by oxidation of base metal components and a slow release of material from an aluminum-rich product layer into the salt. The rate of release was substantially lower than that previously found for iron and iron-based alloys. This would imply that corrosion of iron aluminides could be minimized by maximizing the surface coverage of this aluminum-rich layer either by alloying or by an appropriate preoxidation treatment.

  13. Influence of compositional modifications on the corrosion of iron aluminides of molten nitrate salts

    SciTech Connect

    Tortorelli, P.F.; Bishop, P.S.

    1991-01-01

    The corrosion of iron-aluminum alloys by molten nitrate salt as a function of aluminum, chromium, and other minor elements has been studied as part of an alloy design effort aimed at the development of a strong, ductile, corrosion-resistant FeAl type of aluminide. Short- term weight change data were used to examine the compositional dependence of the corrosion processes that occurred upon exposure of iron aluminides to highly oxidizing nitrate salts of 650{degrees}C. Corrosion resistance was found to increase with increasing aluminum concentrations of the alloy up to approximately 30 at. % Al. Chromium additions to the aluminide were not detrimental and may have improved the corrosion behavior for certain aluminum concentrations. No effects of minor alloying additions (C, B, Ti, and Zr) could be determined. The best overall corrosion resistance as measured by weight change results were obtained for an Fe-35.8 at. % Al aluminide containing some chromium. Based on linear weight loss kinetics, the weight change measurements for the most resistant compositions predict corrosion rates of 300 {mu}m/year or less at 650{degrees}C. These rates are substantially better than typical nickel-based alloys and stainless steels. From a consideration of the weight changes; the microstructural, thermodynamic, and X-ray diffraction data; and the salt analyses, corrosion of iron aluminides by the molten nitrate salt appears to be controlled by oxidation of base metal components and a slow release of material from an aluminum-rich product layer into the salt. The rate of release was substantially lower than that previously found for iron and iron-based alloys. This would imply that corrosion of iron aluminides could be minimized by maximizing the surface coverage of this aluminum-rich layer either by alloying or by an appropriate preoxidation treatment.

  14. Corrosive wear of cast iron under reciprocating lubrication

    SciTech Connect

    Yahagi, Y.; Nagasawa, Y.; Hotta, S.; Mizutani, Y.

    1986-01-01

    In order to study the wear of cylinder bore fundamentally, a reciprocating friction tester was produced and utilized. The friction between a cast iron and a piston-ring and the wear of the cast iron were examined under the corrosive oil with sulphuric acid. The findings indicate that the friction and wear around TDC and BDC was confirmed to be greater than between these reversal points and the friction and wear around the reversal points increased with the sulphuric acid which has caused the deficiency of oil film and the corrosion of the cast iron.

  15. Nitrite reduction and formation of corrosion coatings in zerovalent iron systems.

    PubMed

    Huang, Yong H; Zhang, Tian C

    2006-08-01

    Batch tests were conducted to investigate nitrite reduction in a zerovalent iron (Fe0) system under various conditions. Nitrite at 1.4 mM initial concentration was slowly reduced to nitrogen gas in the first stage (days 1-6), which was mediated by an amorphous, Fe(II)-rich iron oxide coating. The second stage (days 7-14) featured a rapid reduction of nitrite to both ammonia and nitrogen gas and the formation of a more crystalline, magnetite form iron oxide coating. Water reduction by Fe0 occurred concurrently with nitrite reduction from the beginning and contributed significantly to the overall iron corrosion. Nitrite at 14 mM was found to passivate the surface of Fe0 grains with respect to nitrite reduction. Adding aqueous Fe2+ significantly accelerated reduction of nitrite by Fe0 to nitrogen gas with lepidocrocite as the main iron corrosion product. Substantially, though still substoichiometrically, 0.55 mol of Fe2+ were concomitantly consumed per 1.0 mol nitrite reduction, indicating that Fe0 was the main electron source. In the presence of Fe2+, nitrite reduction out-competed water reduction in terms of contributing to the overall iron corrosion. Results of this study help understand complicated interactions between water reduction and nitrite reduction, the roles of surface-bound Fe2+, and the evolution of the iron corrosion coating.

  16. Identification of Corrosion Products Due to Seawater and Fresh Water

    NASA Astrophysics Data System (ADS)

    Gismelseed, A.; Elzain, M.; Yousif, A.; Al Rawas, A.; Al-Omari, I. A.; Widatallah, H.; Rais, A.

    2004-12-01

    Mössbauer and X-ray diffraction (XRD) measurements were performed on corrosion products extracted from the inner surface of two different metal tubes used in a desalination plant in Oman. One of the tubes corroded due to the seawater while the second was corroded due to fresh water. The corrosion products thus resulted due to seawater were scrapped off in to two layers, the easily removable rust from the top is termed outer surface corrosion product and the strongly adhered rust as internal corrosion product. The Mössbauer spectra together with the XRD pattern of the outer surface showed the presence of magnetite (Fe3O4), akaganeite (β-FeOOH), lepidocrocite (γ-FeOOH), goethite (α-FeOOH) and hematite (Fe2O3). The inner surface however showed the presence of akaganite, goethite, and magnetite. On the other hand, the corrosion products due to the fresh water showed only the presence of goethite and magnetite. The mechanism of the corrosion process will be discussed based on the significant differences between the formation of the iron components of the corrosion products due to seawater and the fresh water.

  17. [The corrosion of pure iron in five different mediums].

    PubMed

    Xu, Li; Zhu, Shengfa; Huang, Nan; Li, Xinchang; Zhang, Yu

    2009-08-01

    The sectional test was adopted in this study to investigate the corrosion of pure iron in 0.15 mol/L NaCl solution, Ringer solution, PBS(-) solution, SBF solution and M199 cell culture medium at three different times. The result shows that different mediums have different corrosion effects on pure iron. The arrangement according to the medium's corrosion ability from the strongest to weakest is 0.15 mol/L NaCl solution (Ringer solution), PBS(-) solution, SBF solution and M199 cell culture medium. The results of scanning electron microscopy and energy dispersive X-ray spectrum analyses show that the addition of HPO4(2-), H2POC4-, Ca2+, Mg2+, SO4(2-) and the organic component can inhibit the corrosion to some degree.

  18. Alpha localized radiolysis and corrosion mechanisms at the iron/water interface: Role of molecular species

    NASA Astrophysics Data System (ADS)

    Vandenborre, Johan; Crumière, Francis; Blain, Guillaume; Essehli, Rachid; Humbert, Bernard; Fattahi, Massoud

    2013-02-01

    This paper is devoted to the iron corrosion phenomena induced by the α (4He2+) water radiolysis species studied in conjunction with the production/consumption of H2 at the solid/solution interface. On one hand, the solid surface is characterized during the 4He2+ ions irradiation by in situ Raman spectroscopy; on another hand, the H2 gas produced by the water radiolysis is monitored by ex situ gas measurements. The 4He2+ ions irradiation experiments are provided either by the CEMHTI (E = 5.0 MeV) either by the ARRONAX (E = 64.7 MeV) cyclotron facilities. The iron corrosion occurs only under irradiation and can be slowed down by H2 reductive atmosphere. Pure iron and carbon steel solids are studied in order to show two distinct behaviors of these surfaces vs. the 4He2+ ions water irradiation: the corrosion products identified are the magnetite phase (Fe(II)Fe(III)2O4) correlated to an H2 consumption for pure iron and the lepidocrocite phase (γ-Fe(III)OOH) correlated to an H2 production for carbon steel sample. This paper underlined the correlation between the iron corrosion products formation onto the solid surface and the H2 production/consumption mechanisms. H2O2 species is considered as the single water radiolytic species involved into the corrosion reaction at the solid surface with an essential role in the oxidation reaction of the iron surface. We propose to bring some light to these mechanisms, in particular the H2 and H2O2 roles, by the in situ Raman spectroscopy during and after the 4He2+ ions beam irradiation. This in situ experiment avoids the evolution of the solid surface, in particular phases which are reactive to the oxidation processing.

  19. The impact of gallic acid on iron gall ink corrosion

    NASA Astrophysics Data System (ADS)

    Rouchon-Quillet, V.; Remazeilles, C.; Bernard, J.; Wattiaux, A.; Fournes, L.

    Many old manuscripts suffer from iron-gall ink corrosion, threatening our graphic heritage. Corroded papers become brown and brittle with age. The chemical reactions involved in this corrosion are relatively well known: they include both acidic hydrolysis and oxidation catalysed by free iron(II). Yet, a great variety of iron-gall ink recipes, including a wide range of constituents can be found in the literature and the visual aspect of old inks, can be very different from one inscription to another, even if they have been written on the same sheet of paper. This suggests that even if the free iron(II) plays a dominant role in the paper alteration, the contribution of other ingredients should not be neglected. For this reason, we explored the impact gallic acid may have on the corrosion mechanisms and in particular on the oxidation reactions. These investigations were carried out on laboratory probes prepared with paper sheets immersed in different solutions, all containing the same amount of iron sulphate, and different gallic acid concentrations. These probes were then artificially aged and their degradation state was evaluated by bursting strength measurements, FTIR spectrometry and Mössbauer spectrometry. All these analyses lead us to conclude that gallic acid has an influence on the iron(III)/iron(II) ratio, probably because of its reducing properties.

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

    SciTech Connect

    Serdar, Marijana; Meral, Cagla; Kunz, Martin; Bjegovic, Dubravka; Wenk, Hans-Rudolf; Monteiro, Paulo J.M.

    2015-05-15

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

  1. Corrosion of weathering steel and iron under wet-dry cycling conditions: Influence of the rise of temperature during the dry period

    NASA Astrophysics Data System (ADS)

    Davalos, J.; Gracia, M.; Marco, J. F.; Gancedo, J. R.

    1992-04-01

    The effect of a dry-hot period on the SO2 corrosion of weatherig steel and pure iron under wet-dry cycling was investigated. Corrosion products were identified by Mössbauer spectroscopy and X-ray powder diffraction. The formation of an intermediate corrosion layer of spm α-FeOOH only on weathering steel was the most significant result.

  2. Corrosion of metastable iron alloys in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Wolf, Gerhard K.; Ferber, H.

    1983-05-01

    There exist some examples showing that metastable surface alloys can modify the corrision properties of a substrate in the same way as stable alloys do. In the present paper the corrosion behaviour of metastable surface alloys obtained by implanting gold, lead and mercury in iron was studied in aqueous solution of pH = 5.6. Potentiodynamic current density-potential curves were recorded of the implanted samples without further treatment and after isothermal annealing to temperatures up to 800°C. The results were compared with structural information on the alloys obtained by Turos et al. with α-backscattering and channeling experiments. Gold implantation turned out to enhance the active corrosion rate of iron, while lead and mercury had an impeding effect. The annealing experiments showed that the surface alloying facilitated the passivation of iron as long as the substitutional solid solution was "(meta)stable". After the breakdown at higher annealing temperatures leading to surface migration and clustering of the implanted elements a significant increase of the critical current density for passivation took place. This indicates passivation difficulties caused by the heterogeneous distribution of the "alloying" particles. In general the results suggest that substitutional metastable iron alloys cause in a systematic way corrosion inhibition or enhancement. However, their corrosion properties may change completely for non-substitutional distribution of the alloying elements as originating from annealing at higher temperatures.

  3. Corrosion Behavior of Ceramic Cup of Blast Furnace Hearth by Liquid Iron and Slag

    NASA Astrophysics Data System (ADS)

    Li, Yanglong; Cheng, Shusen; Wang, Zhifeng

    2016-10-01

    Three kinds of sample bricks of ceramic cups for blast furnace hearth were studied by dynamic corrosion tests based on different corrosion systems, i.e., liquid iron system, liquid slag system and liquid iron-slag system. Considering the influence of temperature and sample rotational speed, the corrosion profiles and mass loss of the samples were analyzed. In addition, the microstructure of the corroded samples was observed by optical microscope (OM) and scanning electron microscope (SEM). It was found that the corrosion profiles could be divided into iron corrosion region, slag corrosion region and iron-slag corrosion region via corrosion degree after iron-slag corrosion experiment. The most serious corrosion occurred in iron-slag corrosion region. This is due to Marangoni effect, which promotes a slag film formed between liquid iron and ceramic cup and results in local corrosion. The corrosion of the samples deepened with increasing temperature of liquid iron and slag from 1,623 K to 1,823 K. The variation of slag composition had greater influence on the erosion degree than that of rotational speed in this experiment. Taking these results into account the ceramic cup composition should be close to slag composition to decrease the chemical reaction. A microporous and strong material should be applied for ceramic cup.

  4. Corrosion of high-level radioactive waste iron-canisters in contact with bentonite.

    PubMed

    Kaufhold, Stephan; Hassel, Achim Walter; Sanders, Daniel; Dohrmann, Reiner

    2015-03-21

    Several countries favor the encapsulation of high-level radioactive waste (HLRW) in iron or steel canisters surrounded by highly compacted bentonite. In the present study the corrosion of iron in contact with different bentonites was investigated. The corrosion product was a 1:1 Fe layer silicate already described in literature (sometimes referred to as berthierine). Seven exposition test series (60 °C, 5 months) showed slightly less corrosion for the Na-bentonites compared to the Ca-bentonites. Two independent exposition tests with iron pellets and 38 different bentonites clearly proved the role of the layer charge density of the swelling clay minerals (smectites). Bentonites with high charged smectites are less corrosive than bentonites dominated by low charged ones. The type of counterion is additionally important because it determines the density of the gel and hence the solid/liquid ratio at the contact to the canister. The present study proves that the integrity of the multibarrier-system is seriously affected by the choice of the bentonite buffer encasing the metal canisters in most of the concepts. In some tests the formation of a patina was observed consisting of Fe-silicate. Up to now it is not clear why and how the patina formed. It, however, may be relevant as a corrosion inhibitor.

  5. Morphological and physicochemical characteristics of iron corrosion scales formed under different water source histories in a drinking water distribution system.

    PubMed

    Yang, Fan; Shi, Baoyou; Gu, Junnong; Wang, Dongsheng; Yang, Min

    2012-10-15

    The corrosion scales on iron pipes could have great impact on the water quality in drinking water distribution systems (DWDS). Unstable and less protective corrosion scale is one of the main factors causing "discolored water" issues when quality of water entering into distribution system changed significantly. The morphological and physicochemical characteristics of corrosion scales formed under different source water histories in duration of about two decades were systematically investigated in this work. Thick corrosion scales or densely distributed corrosion tubercles were mostly found in pipes transporting surface water, but thin corrosion scales and hollow tubercles were mostly discovered in pipes transporting groundwater. Magnetite and goethite were main constituents of iron corrosion products, but the mass ratio of magnetite/goethite (M/G) was significantly different depending on the corrosion scale structure and water source conditions. Thick corrosion scales and hard shell of tubercles had much higher M/G ratio (>1.0), while the thin corrosion scales had no magnetite detected or with much lower M/G ratio. The M/G ratio could be used to identify the characteristics and evaluate the performances of corrosion scales formed under different water conditions. Compared with the pipes transporting ground water, the pipes transporting surface water were more seriously corroded and could be in a relatively more active corrosion status all the time, which was implicated by relatively higher siderite, green rust and total iron contents in their corrosion scales. Higher content of unstable ferric components such as γ-FeOOH, β-FeOOH and amorphous iron oxide existed in corrosion scales of pipes receiving groundwater which was less corroded. Corrosion scales on groundwater pipes with low magnetite content had higher surface area and thus possibly higher sorption capacity. The primary trace inorganic elements in corrosion products were Br and heavy metals. Corrosion

  6. Microbial extracellular electron transfer and its relevance to iron corrosion.

    PubMed

    Kato, Souichiro

    2016-03-01

    Extracellular electron transfer (EET) is a microbial metabolism that enables efficient electron transfer between microbial cells and extracellular solid materials. Microorganisms harbouring EET abilities have received considerable attention for their various biotechnological applications, including bioleaching and bioelectrochemical systems. On the other hand, recent research revealed that microbial EET potentially induces corrosion of iron structures. It has been well known that corrosion of iron occurring under anoxic conditions is mostly caused by microbial activities, which is termed as microbiologically influenced corrosion (MIC). Among diverse MIC mechanisms, microbial EET activity that enhances corrosion via direct uptake of electrons from metallic iron, specifically termed as electrical MIC (EMIC), has been regarded as one of the major causative factors. The EMIC-inducing microorganisms initially identified were certain sulfate-reducing bacteria and methanogenic archaea isolated from marine environments. Subsequently, abilities to induce EMIC were also demonstrated in diverse anaerobic microorganisms in freshwater environments and oil fields, including acetogenic bacteria and nitrate-reducing bacteria. Abilities of EET and EMIC are now regarded as microbial traits more widespread among diverse microbial clades than was thought previously. In this review, basic understandings of microbial EET and recent progresses in the EMIC research are introduced.

  7. A Theoretical Study of Carbohydrates as Corrosion Inhibitors of Iron

    NASA Astrophysics Data System (ADS)

    Khalil, Salim M.; Ali-Shattle, Elbashir E.; Ali, Nozha M.

    2013-09-01

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

  8. UO 2 corrosion in an iron waste package

    NASA Astrophysics Data System (ADS)

    Ferriss, E. D. A.; Helean, K. B.; Bryan, C. R.; Brady, P. V.; Ewing, R. C.

    2009-02-01

    In order to investigate the interactions between spent nuclear fuel, corroding iron waste packages, and water under conditions likely to be relevant at the proposed repository at Yucca Mountain, six small-scale waste packages were constructed. Each package differed with respect to water input, exposure to the atmosphere and temperature. Two of the packages contained 0.1 g UO 2. Simulated Yucca Mountain process water (YMPW) was injected into five of the packages at a rate of 200 μl per day for up to 2 years, at which point the solids were characterized with X-ray powder diffraction, scanning electron microscopy, wet chemistry and electron microprobe analysis. Fe(II) is abundant in the corrosion products that form, and the dominant crystalline product in all cases according to X-ray diffraction is magnetite or the structurally similar maghemite. Minor phases included akaganeite (β-FeOOH) and possibly also hematite (Fe 2O 3), lepidocrocite (γ-FeOOH) and green rust (Fe(II) 1-xFe(III) x(OH) 2Y x/n). Under these conditions, UO 2 is expected to alter to the uranyl silicate uranophane (Ca[(UO 2)SiO 3(OH)] 2·5H 2O). Neither oxidation of the UO 2 nor any oxidized (uranyl) solid was observed, suggesting that conditions were sufficiently reducing to kinetically hinder U(IV) oxidation.

  9. Electrochemical corrosion of iron-magnesium-alumina spinel (FMAS) in molten potassium salts and coal slag

    SciTech Connect

    Marchant, D.D.; Griffin, C.W.; Bates, J.L.

    1981-01-01

    Iron, magnesium-alumina spinel (FMAS) (0.25 Fe/sub 3/O/sub 4/ . 0.75 MgAl/sub 2/O/sub 4/) has been considered for use as an electrode in magnetohydrodynamic (MHD) generator channels. Predominantly an electronic conductor, FMAS has adequate electrical conductivity (>1 S/m) above 520/sup 0/K. In addition, FMAS can be easily fabricated into a form and sintered in air to >90% theoretical density and has a melting point of 2124 +- 20/sup 0/K. Laboratory tests to measure both the electrochemical and chemical corrosion of FMAS in molten K/sub 2/CO/sub 3/, K/sub 2/SO/sub 4/ and coal slags were developed at the Pacific Northwest Laboratory to evaluate the relative corrosion of FMAS. Under isothermal conditions, a direct electric current was passed between an anode and a cathode through a molten electrolyte. The molten coal slags were synthetic high-calcium, low-iron Montana Rosebud and low-calcium, high-iron Illinois No. 6. Evaluations of electrochemical corrosion were made as functions of current density, temperature, and slag composition. These results were compared to those of FMAS tested without electric current. The corrosion rates and reaction products were investigated by optical microscopy and scanning electron microscopy. Overall, FMAS has too-high an electrochemical corrosion rate to be considered as MHD electrodes in Montana Rosebud coal slag or in systems where only molten potassium salts are present. However, FMAS may be considered for use in high-iron coal slags although the corrosion rates are still quite high even in these slags.

  10. Enhanced Corrosion Resistance of Iron-Based Amorphous Alloys

    SciTech Connect

    Rebak, R B; Day, S D; Lian, T; Aprigliano, L F; Hailey, P D; Farmer, J C

    2007-02-18

    Iron-based amorphous alloys possess enhanced hardness and are highly resistant to corrosion, which make them desirable for wear applications in corrosive environments. It was of interest to examine the behavior of amorphous alloys during anodic polarization in concentrated salt solutions and in the salt-fog testing. Results from the testing of one amorphous material (SAM2X5) both in ribbon form and as an applied coating are reported here. Cyclic polarization tests were performed on SAM2X5 ribbon as well as on other nuclear engineering materials. SAM2X5 showed the highest resistance to localized corrosion in 5 M CaCl{sub 2} solution at 105 C. Salt fog tests of 316L SS and Alloy 22 coupons coated with amorphous SAM2X5 powder showed resistance to rusting. Partial devitrification may be responsible for isolated pinpoint rust spots in some coatings.

  11. Effect of sulfate on the transformation of corrosion scale composition and bacterial community in cast iron water distribution pipes.

    PubMed

    Yang, Fan; Shi, Baoyou; Bai, Yaohui; Sun, Huifang; Lytle, Darren A; Wang, Dongsheng

    2014-08-01

    The chemical stability of iron corrosion scales and the microbial community of biofilm in drinking water distribution system (DWDS) can have great impact on the iron corrosion and corrosion product release, which may result in "red water" issues, particularly under the situation of source water switch. In this work, experimental pipe loops were set up to investigate the effect of sulfate on the dynamical transformation characteristics of iron corrosion products and bacterial community in old cast iron distribution pipes. All the test pipes were excavated from existing DWDS with different source water supply histories, and the test water sulfate concentration was in the range of 50-350 mg/L. Pyrosequencing of 16S rRNA was used for bacterial community analysis. The results showed that iron release increased markedly and even "red water" occurred for pipes with groundwater supply history when feed water sulfate elevated abruptly. However, the iron release of pipes with only surface water supply history changed slightly without noticeable color even the feed water sulfate increased multiply. The thick-layered corrosion scales (or densely distributed tubercles) on pipes with surface water supply history possessed much higher stability due to the larger proportion of stable constituents (mainly Fe3O4) in their top shell layer; instead, the rather thin and uniform non-layered corrosion scales on pipes with groundwater supply history contained relatively higher proportion of less stable iron oxides (e.g. β-FeOOH, FeCO3 and green rust). The less stable corrosion scales tended to be more stable with sulfate increase, which was evidenced by the gradually decreased iron release and the increased stable iron oxides. Bacterial community analysis indicated that when switching to high sulfate water, iron reducing bacteria (IRB) maintained dominant for pipes with stable corrosion scales, while significant increase of sulfur oxidizing bacteria (SOB), sulfate reducing bacteria (SRB

  12. Fretting corrosion resistance and fretting corrosion product cytocompatibility of ferritic stainless steel.

    PubMed

    Xulin, S; Ito, A; Tateishi, T; Hoshino, A

    1997-01-01

    To avoid nickel ion release from SUS317L as an implant material, a new type of nickel, commercially free, of high purity, and high chromium ferritic stainless steel, was developed. The new stainless steel (FJ) was studied for aspects of fretting corrosion and cytocompatibility compared with SUS317L. A pin-on-plate fretting corrosion test in an artificial physiologic solution, and cell culture in media with the addition of the artificial physiologic solution used for fretting was conducted. Resistance to the fretting induced crevice corrosion of FJ was higher than that of SUS317L because of the favorable electrochemical stability of the FJ alloy. The amount of iron ion or colloidal fine particles released from FJ was about a quarter of that from SUS317L, although the weight loss of a pin of FJ was almost 5/3 that of SUS317L. The artificial physiologic solution used for SUS317L fretting was more harmful to the growth of L929 and MC3T3-E1 cells than that used for FJ fretting. FJ was therefore superior to SUS317L as a biomaterial, judging from the resistance to fretting-induced crevice corrosion, electrochemical stability, and the cytocompatibility of fretting corrosion products.

  13. Investigation on corrosion stratigraphy and morphology in some Iron Age bronze alloys vessels by OM, XRD and SEM-EDS methods

    NASA Astrophysics Data System (ADS)

    Oudbashi, Omid; Hasanpour, Ata; Davami, Parviz

    2016-04-01

    The recently study of the corrosion in some bronze artefacts from the Sangtarashan Iron Age site, western Iran, was established to identify corrosion morphology and mechanism in these objects. The corrosion layers in 22 samples were studied by optical microscopy, scanning electron microscopy-energy-dispersive X-ray spectroscopy and X-ray diffraction methods. The results showed that a thin corrosion crust has formed on the surface of bronzes with a triple-layer structure, including two internal and one external corrosion layers. The formation of these layers is due to copper leaching from the bronze surface. The internal corrosion part has been a compact, tin-rich corrosion/oxidation product (noble patina) with some evidences from original metallurgical aspects of the bronze as well as a very thin layer beneath the tin-rich layer. External corrosion products have been identified as basic copper carbonates, malachite and azurite. Based on the results, the corrosion morphology in the Sangtarashan Iron Age bronzes is due to long-term burial in an appropriate environment in a moderately corrosive soil. Although it is the first time to investigate Iron Age bronzes from Iran, this corrosion morphology is partially similar to type I corrosion morphology observed in archaeological bronze objects; nevertheless, some deviations are visible in comparison with previously established patterns.

  14. Autotrophic denitrification using hydrogen generated from metallic iron corrosion.

    PubMed

    Sunger, Neha; Bose, Purnendu

    2009-09-01

    Hydrogenotrophic denitrification was demonstrated using hydrogen generated from anoxic corrosion of metallic iron. For this purpose, a mixture of hydrogenated water and nitrate solution was used as reactor feed. A semi-batch reactor with nitrate loading of 2000 mg m(-3) d(-1) and hydraulic retention time (HRT) of 50 days produced effluent with nitrate concentration of 0.27 mg N L(-1) (99% nitrate removal). A continuous flow reactor with nitrate loading of 28.9 mg m(-3) d(-1) and HRT of 15.6 days produced effluent with nitrate concentration of approximately 0.025 mg N L(-1) (95% nitrate removal). In both cases, the concentration of nitrate degradation by-products, viz., ammonia and nitrite, were below detection limits. The rate of denitrification in the reactors was controlled by hydrogen availability, and hence to operate such reactors at higher nitrate loading rates and/or lower HRT than reported in the present study, hydrogen concentration in the hydrogenated water must be significantly increased.

  15. Crevice corrosion products of dental amalgam

    SciTech Connect

    Sutow, E.J.; Jones, D.W.; Hall, G.C.; Owen, C.G. )

    1991-07-01

    The objective of this study was to determine the in vitro corrosion products that resulted from crevice corrosion of low- and high-copper dental amalgams. Specimens were potentiostatically polarized in a chloride-containing electrolyte while set against a PTFE surface to form a crevice. After 16 h, corrosion products were examined by light microscopy, SEM, EDS, and XRD. Analysis showed the presence of three previously reported products (Sn4(OH)6Cl2, SnO, and Cu2O) and a new product, CuCl, which formed on high-copper, {gamma} 2-free amalgams. Thermodynamic considerations show that CuCl is stable for the reported in vivo potentials of amalgam restorations and the high acidity and high chloride ion concentration associated with crevice corrosion.

  16. Anodic activation of iron corrosion in clay media under water-saturated conditions at 90 degrees C: characterization of the corrosion interface.

    PubMed

    Schlegel, Michel L; Bataillon, Christian; Blanc, Cécile; Prêt, Dimitri; Foy, Eddy

    2010-02-15

    To understand the process governing iron corrosion in clay over centuries, the chemical and mineralogical properties of solids formed by free or anodically activated corrosion of iron in water-saturated clay at 90 degrees C over 4 months were probed using microscopic and spectroscopic techniques. Free corrosion led to the formation of an internal discontinuous thin (<3 microm thick) magnetite layer, an external layer of Fe-rich phyllosilicate, and a clay transformation layer containing Ca-doped siderite (Ca(0.2)Fe(0.8)CO(3)). The thickness of corroded iron equaled approximately 5-7 microm, consistent with previous studies. Anodic polarization resulted in unequally distributed corrosion, with some areas corrosion-free and others heavily corroded. Activated corrosion led to the formation of an inner magnetite layer, an intermediate Fe(2)CO(3)(OH)(2) (chukanovite) layer, an outer layer of Fe-rich 7 A-phyllosilicate, and a transformed matrix layer containing siderite (FeCO(3)). The corroded thickness was estimated to 85 microm, less than 30% of the value expected from the supplied anodic charge. The difference was accounted for by reoxidation at the anodically polarized surface of cathodically produced H(2)(g). Thus, free or anodically activated corroding conditions led to structurally similar interfaces, indicating that anodic polarization can be used to probe the long-term corrosion of iron in clay. Finally, corrosion products retained only half of Fe oxidized by anodic activation. Missing Fe probably migrated in the clay, where it could interact with radionuclides released by alteration of nuclear glass.

  17. Glass corrosion in the presence of iron-bearing materials and potential corrosion suppressors

    SciTech Connect

    Reiser, Joelle T.; Neill, Lindsay; Weaver, Jamie L.; Parruzot, Benjamin; Musa, Christopher; Neeway, James J.; Ryan, Joseph V.; Qafoku, Nikolla; Gin, Stephane; Wall, Nathalie

    2015-07-16

    A complete understanding of radioactive waste glass interactions with near-field materials is essential for appropriate nuclear waste repository performance assessment. In many geologic repository designs, Fe is present in both the natural environment and in the containers that will hold the waste glasses. In this paper we discuss investigations into the alteration of International Simple Glass (ISG) in the presence of Fe0 foil and hematite (Fe2O3). ISG alteration is more pronounced in the presence of Fe0 than with hematite. Additionally, minimal glass corrosion is observed for distances equal to 5 mm between Fe materials and ISG, but substantial glass corrosion is observed for systems exhibiting full contact between Fe0 material and ISG. Diatomaceous earth appears to be a better corrosion suppressant than silica when present with iron and ISG.

  18. Corrosion of stainless steel during acetate production

    SciTech Connect

    Qi, J.S.; Lester, G.C.

    1996-07-01

    Corrosion of types 304, 304L, 316, and 316L stainless steel (SS) during the esterification of acetic acid and alcohol or glycol ether was investigated. The catalyst for this reaction, sulfuric acid or para-toluene sulfonic acid (PTSA), was shown to cause more corrosion on reactor equipment than CH{sub 3}COOH under the process conditions commonly practiced in industry. The corrosive action of the catalyst occurred only in the presence of water. Thus, for the batch processes, corrosion occurred mostly during the initial stage of esterification, where water produced by the reaction created an aqueous environment. After water was distilled off, the corrosion rate declined to a negligible value. The corrosion inhibitor copper sulfate, often used in industrial acetate processes, was found to work well for a low-temperature process (< 95 C) such as in production of butyl acetate, but it accelerated corrosion in the glycol ether acetate processes where temperatures were > 108 C. Process conditions that imparted low corrosion rates were determined.

  19. Corrosion resistant iron aluminides exhibiting improved mechanical properties and corrosion resistance

    DOEpatents

    Liu, C.T.; McKamey, C.G.; Tortorelli, P.F.; David, S.A.

    1994-06-14

    The specification discloses a corrosion-resistant intermetallic alloy comprising, in atomic percent, an FeAl iron aluminide containing from about 30 to about 40% aluminum alloyed with from about 0.01 to 0.4% zirconium and from 0.01 to about 0.8% boron. The alloy exhibits considerably improved room temperature ductility for enhanced usefulness in structural applications. The high temperature strength and fabricability is improved by alloying with molybdenum, carbon, chromium and vanadium. 9 figs.

  20. Corrosion resistant iron aluminides exhibiting improved mechanical properties and corrosion resistance

    DOEpatents

    Liu, Chain T.; McKamey, Claudette G.; Tortorelli, Peter F.; David, Stan A.

    1994-01-01

    The specification discloses a corrosion-resistant intermetallic alloy comprising, in atomic percent, an FeAl iron aluminide containing from about 30 to about 40% aluminum alloyed with from about 0.01 to 0.4% zirconium and from 0.01 to about 0.8% boron. The alloy exhibits considerably improved room temperature ductility for enhanced usefulness in structural applications. The high temperature strength and fabricability is improved by alloying with molybdenum, carbon, chromium and vanadium.

  1. Long-term in vivo corrosion behavior, biocompatibility and bioresorption mechanism of a bioresorbable nitrided iron scaffold.

    PubMed

    Lin, Wenjiao; Qin, Li; Qi, Haiping; Zhang, Deyuan; Zhang, Gui; Gao, Runlin; Qiu, Hong; Xia, Ying; Cao, Ping; Wang, Xiang; Zheng, Wei

    2017-03-14

    Pure iron as a potential bioresorbable material for bioresorbable coronary scaffold has major disadvantages of slow corrosion and bioresorption. However, so far, there are neither quantitative data of long-term in vivo corrosion nor direct experimental evidence for bioresorption of pure iron and its alloys, which are fundamental and vital for developing novel Fe-based alloys overcoming the intrinsic drawbacks of pure iron. This work systemically investigated scaffold performance, long-term in vivo corrosion behavior and biocompatibility of a nitrided iron coronary scaffold and explored its bioresorption mechanism. It was found that the 70μm Fe-based scaffold was superior to a state of the art Co-Cr alloy stent (Xience Prime(TM)) in terms of crossing profile, recoil and radial strength. Mass loss was 76.0 ± 8.5 wt.% for the nitrided iron scaffold and 44.2 ± 11.4 wt.% for the pure iron scaffold after 36 months implantation in rabbit abdominal aorta (p<0.05). The Fe-based scaffold showed good long-term biocompatibility in both rabbit and porcine model. Its insoluble corrosion products were demonstrated biosafe and could be cleared away by macrophages from in situ to adventitia to be indiscernible by Micro Computed Tomography and probably finally enter the lymphatics and travel to lymph nodes after 53 months implantion in porcine coronary artery. The results indicate that the nitrided iron scaffold with further improvements shall be promising for coronary application.

  2. Coking products as corrosion inhibitors

    SciTech Connect

    Antonov, A.V.; Petrenko, V.G.; Frolova, R.P.; Kurinnaya, S.N.

    1982-11-06

    Activated sludge and froth from the biological treatment of coke plant waste waters has been determined to be a corrosion inhibitor in both neutral and acidic media, due to the presence of unreacted coking derived inhibitors, bacteriological formation of inhibitors, bacterial organisms, humic-type organics and traces of germanium, zinc, mercury and manganese. The corrosive liquids tested were, river water, technical system water, gas cooler aqueous condensate, gas collector condensate and coking waste water before and after treatment, the substrate being St 3 steel plates (45 X 45 X 5 M) (time 24-30 hr (acid media) and 934 hr (neutral media)). The activated sludge (25 g/l) reduced acid media corrosion rate by 10/sup 3/, the protective effect being 99% for the test liquids: Sludge is more effective than the froth.

  3. High temperature chlorosilane corrosion of iron and AISI 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Aller, Joshua Loren

    Chlorosilane gas streams are used at high temperatures (>500°C) throughout the semiconductor, polycrystalline silicon, and fumed silica industries, primarily as a way to refine, deposit, and produce silicon and silicon containing materials. The presence of both chlorine and silicon in chlorosilane species creates unique corrosion environments due to the ability of many metals to form both metal-chlorides and metal-silicides, and it is further complicated by the fact that many metal-chlorides are volatile at high-temperatures while metal-silicides are generally stable. To withstand the uniquely corrosive environments, expensive alloys are often utilized, which increases the cost of final products. This work focuses on the corrosion behavior of iron, the primary component of low-cost alloys, and AISI 316L, a common low-cost stainless steel, in environments representative of industrial processes. The experiments were conducted using a customized high temperature chlorosilane corrosion system that exposed samples to an atmospheric pressure, high temperature, chlorosilane environment with variable input amounts of hydrogen, silicon tetrachloride, and hydrogen chloride plus the option of embedding samples in silicon during the exposure. Pre and post exposure sample analysis including scanning electron microscopy, x-ray diffraction, energy dispersive x-ray spectroscopy, and gravimetric analysis showed the surface corrosion products varied depending on the time, temperature, and environment that the samples were exposed to. Most commonly, a volatile chloride product formed first, followed by a stratified metal silicide layer. The chlorine and silicon activities in the corrosion environment were changed independently and were found to significantly alter the corrosion behavior; a phenomenon supported by computational thermodynamic equilibrium simulations. It was found that in comparable environments, the stainless steel corroded significantly less than the pure iron. This

  4. Effect of extracellular polymeric substances on corrosion of cast iron in the reclaimed wastewater.

    PubMed

    Jin, Juntao; Wu, Guangxue; Zhang, Zhenhua; Guan, Yuntao

    2014-08-01

    Microorganisms were cultured in the R2A medium with inoculum from biofilm in a reclaimed wastewater distribution system and then extracellular polymeric substances (EPS) were extracted from the culture. Characterization of EPS and their effects on the corrosion of cast iron were examined. EPS extracted from different culturing stages contained different proportions of protein and polysaccharide but with similar functional groups. All types of EPS could inhibit cast iron corrosion and the EPS from the stationary stage had the highest inhibition efficiency. The inhibition efficiency was increased with addition of a small amount of EPS while decreased with excessive amount of EPS. EPS formed a protective film on the metal surface, which retarded the cathodic reduction of oxygen. Excessive amount of EPS promoted anodic dissolution through EPS-Fe binding. The CO and C(O, N) in EPS could be the anodic electrochemical sites with possible products of C(C, H).

  5. Corrosion performance of iron aluminides in fossil energy environments

    SciTech Connect

    Natesan, K.

    1997-12-01

    Corrosion of metallic structural materials in complex gas environments of coal gasification and combustion is a potential problem. The corrosion process is dictated by concentrations of two key constituents: sulfur as H{sub 2}S or SO{sub 2} and chlorine as HCl. This paper presents a comprehensive review of the current status of the corrosion performance of alumina scales that are thermally grown on Fe-base alloys, including iron aluminides, in multicomponent gas environments of typical coal-conversion systems. Mechanisms of scale development/breakdown, performance envelopes for long-term usage of these materials, approaches to modifying the surfaces of engineering alloys by cladding or coating them with intermetallics, and in-service experience with these materials are emphasized. The results are compared with the performance of chromia-forming alloys in similar environments. The paper also discusses the available information on corrosion performance of alloys whose surfaces were enriched with Al by the electrospark deposition process or by weld overlay techniques.

  6. Corrosion performance of iron aluminides in single- and multioxidant environments.

    SciTech Connect

    Natesan, K.

    1998-06-22

    Iron aluminide intermetallics are being developed for use as structural materials and/or as cladding for conventional engineering alloys. In addition to their strength advantages, these materials exhibit excellent resistance to corrosion in single- and multioxidant environments at elevated temperatures through the formation of slow-growing, adherent alumina scales. Even though these intermetallics develop protective oxide scales in single-oxidant environments, the simultaneous presence of several reactants in the environment (typical of practical systems) can lead to development of oxide scales that are nonprotective and that undergo breakaway corrosion, or to nonoxide scales that are detrimental to the performance of the underlying alloy. This paper describes the corrosion performance of Fe-Al intermetallics in environments that contain sulfur, carbon, chlorine, and oxygen and that are typical of fossil energy systems. Emphasis is on mechanisms of scale development and breakdown, performance envelopes for long-term usage of these materials, and approaches to modifying the surfaces of engineering alloys by cladding or coating them with intermetallics to improve their corrosion resistance.

  7. Graphitic corrosion -- Don`t forget about buried cast iron pipes

    SciTech Connect

    Freeman, S.R.

    1999-08-01

    Graphitic corrosion is a form of de-alloying or selective leaching that occurs in cast iron material. This corrosion mechanism is unique to gray cast irons and is caused by the graphitic matrix present. The graphite is cathodic to the iron matrix. Exposure to an electrolyte results in leaching of the iron matrix, leaving behind a porous mass of graphite flakes. Graphite corrosion often occurs in buried gray cast iron pipes, although exposure to an aqueous environment is all that is necessary for the de-alloying to occur. The process of de-alloying in cast iron typically is long-term, taking several years to occur. In fact, many cases of graphitic corrosion-caused failure in cast iron piping occur in piping that has been in service for 50 years or more. Mechanical testing to determine the tensile strength of cast iron can provide information regarding the remaining strength of the pipe.

  8. Corrosion Product Film-Induced Stress Facilitates Stress Corrosion Cracking

    PubMed Central

    Wang, Wenwen; Zhang, Zhiliang; Ren, Xuechong; Guan, Yongjun; Su, Yanjing

    2015-01-01

    Finite element analyses were conducted to clarify the role of corrosion product films (CPFs) in stress corrosion cracking (SCC). Flat and U-shaped edge-notched specimens were investigated in terms of the CPF-induced stress in the metallic substrate and the stress in the CPF. For a U-shaped edge-notched specimen, the stress field in front of the notch tip is affected by the Young’s modulus of the CPF and the CPF thickness and notch geometry. The CPF-induced tensile stress in the metallic substrate is superimposed on the applied load to increase the crack tip strain and facilitate localized plasticity deformation. In addition, the stress in the CPF surface contributes to the rupture of the CPFs. The results provide physical insights into the role of CPFs in SCC. PMID:26066367

  9. Iron Corrosion Observations: Pu(VI)-Fe Reduction Studies

    SciTech Connect

    Reed, Donald T.; Swanson, Juliet S.; Richmann, Michael K.; Lucchini, Jean-Francois; Borkowski, Marian

    2012-09-11

    Iron and Pu Reduction: (1) Very different appearances in iron reaction products were noted depending on pH, brine and initial iron phase; (2) Plutonium was associated with the Fe phases; (3) Green rust was often noted at the higher pH; (4) XANES established the green rust to be an Fe2/3 phase with a bromide center; and (5) This green rust phase was linked to Pu as Pu(IV).

  10. Determining the Effect of Environmental Conditions on Iron Corrosion by Atomic Absorption

    ERIC Educational Resources Information Center

    Malel, Esteban; Shalev, Deborah E.

    2013-01-01

    Iron corrosion is a complex process that occurs when iron is exposed to oxygen and humidity and is exacerbated by the presence of chloride ions. The deterioration of iron structures or other components can be costly to society and is usually evaluated by following the properties of the corroding material. Here, the iron ions released into solution…

  11. Determining the Effect of Environmental Conditions on Iron Corrosion by Atomic Absorption

    ERIC Educational Resources Information Center

    Malel, Esteban; Shalev, Deborah E.

    2013-01-01

    Iron corrosion is a complex process that occurs when iron is exposed to oxygen and humidity and is exacerbated by the presence of chloride ions. The deterioration of iron structures or other components can be costly to society and is usually evaluated by following the properties of the corroding material. Here, the iron ions released into solution…

  12. Statistical analyses of field corrosion data for ductile cast iron pipes buried in sandy marine sediments

    SciTech Connect

    Kajiyama, F.; Koyama, Y.

    1997-02-01

    Field corrosion studies were conducted on bare, ductile cast iron pipes buried 17 y in sandy marine sediment classified as sandy soil and containing iron bacteria, sulfate-reducing bacteria (SRB), and other bacteria. Chemical and biochemical analyses of the sediment were performed in the laboratory. Correlation between the maximum corrosion depth (P{sub max}) and 21 environmental factors was evaluated by applying a correlation analysis. On that basis, the factors controlling corrosion damage were considered by quantification theory analysis. A corrosion mechanism was presented to explain the corrosion phenomena. The corrosion site had a positive correlation with the anaerobic site, characterized by particularly high levels of water content and ferrous sulfide generated by SRB. Corrosion was classified as graphitic and attributed to formation of extensive tubercles resulting from high activity of iron bacteria in the bicarbonate enriched soil.

  13. Corrosion, stress corrosion cracking, and electrochemistry of the iron and nickel base alloys in caustic environments

    SciTech Connect

    Koehler, R.; Beck, F. H.; Agrawal, A. K.; Soendjasmono, B.; Staehle, R. W.

    1980-02-01

    The electrochemical behavior of high purity (99.95% to 99.99%) iron in 0.6M NaCl and 1.0M Na/sub 2/SO/sub 4/ containing H/sub 2/S (50 ppM to 34,000 ppM) was studied using cyclic voltammetry, chronoamperometry, and slow scan rate polarization. Results have indicated that iron does undergo passivation in sulfate solutions containing H/sub 2/S. Iron dissolution depends on the presence of Cl/sup -/, the concentration of H/sub 2/S and solution pH. An equation is given that describes the anodic Tafel current densities. The slow strain rate test was used to evaluate the effect of electrode potential on the susceptibility of 2-1/4Cr, Mo steel to stress corrosion cracking in boiling 50% NaOH solution. Susceptibility decreased and general corrosion increased with increasing potentials. Failures contained a combination of ductile and brittle fracture. Time-to-failure was longest for controlled potentials of -700 and -600mV (Hg/HgO reference) in the -1100 to -400mV range used in this study.

  14. Corrosion behavior of carbon steel in the presence of two novel iron-oxidizing bacteria isolated from sewage treatment plants.

    PubMed

    Ashassi-Sorkhabi, H; Moradi-Haghighi, M; Zarrini, G; Javaherdashti, R

    2012-02-01

    In this work, two novel iron oxidizing bacteria (IOB), namely Gordonia sp. MZ-89 and Enterobacter sp. M01101, were isolated from sewage treatment plants and identified by biochemical and molecular methods. Then, microbially influenced corrosion (MIC) of carbon steel in the presence of these bacteria was investigated. The electrochemical techniques such as potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS) were used to measure the corrosion rate and observe the corrosion mechanism. The results showed that the existence of these microorganisms decreased the corrosion potential and enhanced the corrosion rate. Scanning electron microscopy (SEM) images revealed the ground boundary attacks and pitting on carbon steel samples in the presence of these bacteria after polarization. Corrosion scales were identified with X-ray diffraction (XRD). It was demonstrated that these bacteria can greatly affect the crystalline phase of corrosion products that also confirmed by SEM results. It was inferred that these bacteria were responsible for the corrosion of carbon steel, especially in the form of localized corrosion.

  15. Can Dynamic Bubble Templating Play a Role in Corrosion Product Morphology?

    SciTech Connect

    Gerke, T.L.; Scheckel, K.G.; Ray, R.I.; Little, B.J.

    2012-05-09

    Dynamic templating as a result of cathodic hydrogen gas production is suggested as a possible mechanism for the formation of tube-like corrosion products on an unlined cast iron pipe in a drinking water distribution system. Mounds of corrosion product, with protruding tubes and freestanding tubes, were observed within a single 30 cm section of piping. Internal morphologies for all shapes were texturally complex although mineralogically simple, composed of two iron oxide/oxyhydroxides minerals: {alpha}-FeOOH (goethite) and Fe{sub 3}O{sub 4} (magnetite). Static templating by either microorganisms or minerals was rejected as a possible mechanism for tube formation in this study.

  16. Effect of sulfate on the transformation of corrosion scale composition and bacterial community in cast iron water distribution pipes

    EPA Science Inventory

    The stability of iron corrosion products and the bacterial composition of biofilm in drinking water distribution systems (DWDS) could have great impact on the water safety at the consumer ends. In this work, pipe loops were setup to investigate the transformation characteristics ...

  17. Effect of sulfate on the transformation of corrosion scale composition and bacterial community in cast iron water distribution pipes

    EPA Science Inventory

    The stability of iron corrosion products and the bacterial composition of biofilm in drinking water distribution systems (DWDS) could have great impact on the water safety at the consumer ends. In this work, pipe loops were setup to investigate the transformation characteristics ...

  18. Characteristics of iron corrosion scales and water quality variations in drinking water distribution systems of different pipe materials.

    PubMed

    Li, Manjie; Liu, Zhaowei; Chen, Yongcan; Hai, Yang

    2016-12-01

    Interaction between old, corroded iron pipe surfaces and bulk water is crucial to the water quality protection in drinking water distribution systems (WDS). Iron released from corrosion products will deteriorate water quality and lead to red water. This study attempted to understand the effects of pipe materials on corrosion scale characteristics and water quality variations in WDS. A more than 20-year-old hybrid pipe section assembled of unlined cast iron pipe (UCIP) and galvanized iron pipe (GIP) was selected to investigate physico-chemical characteristics of corrosion scales and their effects on water quality variations. Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Inductively Coupled Plasma (ICP) and X-ray Diffraction (XRD) were used to analyze micromorphology and chemical composition of corrosion scales. In bench testing, water quality parameters, such as pH, dissolved oxygen (DO), oxidation reduction potential (ORP), alkalinity, conductivity, turbidity, color, Fe(2+), Fe(3+) and Zn(2+), were determined. Scale analysis and bench-scale testing results demonstrated a significant effect of pipe materials on scale characteristics and thereby water quality variations in WDS. Characteristics of corrosion scales sampled from different pipe segments show obvious differences, both in physical and chemical aspects. Corrosion scales were found highly amorphous. Thanks to the protection of zinc coatings, GIP system was identified as the best water quality stability, in spite of high zinc release potential. It is deduced that the complicated composition of corrosion scales and structural break by the weld result in the diminished water quality stability in HP system. Measurement results showed that iron is released mainly in ferric particulate form.

  19. Corrosion resistance of cast irons and titanium alloys as reference engineered metal barriers for use in basalt geologic storage: a literature assessment

    SciTech Connect

    Charlot, L.A.; Westerman, R.E.

    1981-07-01

    A survey and assessment of the literature on the corrosion resistance of cast irons and low-alloy titanium are presented. Selected engineering properties of cast iron and titanium are briefly described; however, the corrosion resistance of cast iron and titanium in aqueous solutions or in soils and their use in a basalt repository are emphasized. In evaluating the potential use of cast iron and titanium as structural barrier materials for long-lived nuclear waste packages, it is assumed that titanium has the general corrosion resistance to be used in relatively thin cross sections whereas the cost and availability of cast iron allows its use even in very thick cross sections. Based on this assumption, the survey showed that: The uniform corrosion of low-alloy titanium in a basalt environment is expected to be extremely low. A linear extrapolation of general corrosion rates with an added corrosion allowance suggests that a 3.2- to 6.4-mm-thick wall may have a life of 1000 yr. Pitting and crevice corrosion are not likely corrosion modes in basalt ground waters. It is also unlikely that stress corrosion cracking (SCC) will occur in the commercially pure (CP) titanium alloy or in palladiumor molybdenum-alloyed titanium materials. Low-alloy cast irons may be used as barrier metals if the environment surrounding the metal keeps the alloy in the passive range. The solubility of the corrosion product and the semipermeable nature of the oxide film allow significant uniform corrosion over long time periods. A linear extrapolation of high-temperature corrosion rates on carbon steels and corrosion rates of cast irons in soils gives an estimated metal penetration of 51 to 64 mm after 1000 yr. A corrosion allowance of 3 to 5 times that suggests that an acceptable cast iron wall may be from 178 to 305 mm thick. Although they cannot be fully assessed, pitting and crevice corrosion should not affect cast iron due to the ground-water chemistry of basalt.

  20. Wear of iron and nickel in corrosive liquid environments

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa; Rengstorff, George W. P.

    1987-01-01

    Friction and wear behavior of Fe and Ni sliding on aluminum oxide in aerated sulfuric acid and hydrochloric acid were investigated. The results show that the concentration of acid is an important factor in controlling the metal loss caused by wear corrosion processes in the acids. At very dilute acid concentration (10 to the -4 N), Fe behaves differently from Ni. Fe develops a soft, friable deposit, while Ni develops no corrosion layer. The formation and removal of the corrosion deposit on Fe resulted in high metal loss and coefficient of friction, as compared to the relatively low metal loss and coefficient of friction observed for Ni. At slightly higher acid concentration (10 to the -3 and 10 to the -2 N), no corrosion products were produced on both Fe and Ni. Wear of Fe and Ni was generally at a minimum. At higher acid concentration (10 to the -1 N and above), loss of Fe and Ni increased as the acid concentration increased. In sulfuric acid the maximum loss of both Fe and Ni was at 7.5 N (30%) concentration, and the metal losses of both Fe and Ni dropped markedly at 15 N (50%) and above. In hydrochloric acid, however, the Fe loss continued to increase with the increase of acid concentration, and the maximum Fe loss occurred in the most concentrated acid (12.1 N, 37%). There were variations in loss with Ni from specimen to specimen examined in hydrochloric acids (10 to the -1 N and above). The coefficient of friction for Ni increased slightly with an increase in acid concentration up to 10 to the -2 N. When corrosion started to dominate in the wear-corrosion process, the coefficient of friction decreased in both sulfuric and hydrochloric acids at 10 to the -1 N and above.

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

    NASA Astrophysics Data System (ADS)

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

    2017-04-01

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

  2. Friction and Wear of Iron in Corrosive Media

    NASA Technical Reports Server (NTRS)

    Rengstorff, G. W. P.; Miyoshi, K.; Buckley, D. H.

    1982-01-01

    Friction and wear experiments were conducted with elemental iron exposed to various corrosive media including two acids, base, and a salt. Studies involved various concentrations of nitric and sulfuric acids, sodium hydroxide, and sodium chloride. Load and reciprocating sliding speed were kept constant. With the base NaOH an increase in normality beyond 0.01 N resulted in a decrease in both friction and wear. X-ray photoelectron spectroscopy (XPS) analysis of the surface showed a decreasing concentration of ferric oxide (Fe2O3) on the iron surface with increasing NaOH concentration. With nitric acid (HNO3) friction decreased in solutions to 0.05 N, beyond which no further change in friction was observed. The concentration of Fe2O3 on the surface continued to increase with increasing normality. XPS analysis revealed the presence of sulfates in addition of Fe2O3 on surfaces exposed to sulfuric acid and iron chlorides but no sodium on surfaces exposed to NaCl.

  3. Interfacial corrosion on iron at the passive potential region

    SciTech Connect

    Teschke, O.

    1987-07-01

    Previous authors have shown by interference microscopy and ellipsometry that the spontaneous spreading of nonpolar liquids on smooth clean metal surfaces is characterized by the advance from the bulk liquid of a primary film less than 10/sup 3/ A thick, usually followed by a thicker secondary film assigned to the Marangoni effect. Others have shown that metastable thin film could be produced on platinum electrodes by immersion followed by slow draining under high potential, although they were never observed to form spontaneously. In this paper we experimentally show that this precursory film is involved in the corrosion of iron electrodes at the liquid-electrode interface, in various sulfuric acid concentrations, polarized at -- 500mV vs SCE.

  4. Computational study: Reduction of iron corrosion in lead coolant of fast nuclear reactor

    SciTech Connect

    Arkundato, Artoto; Su'ud, Zaki; Abdullah, Mikrajuddin; Widayani

    2012-06-20

    In this paper we report molecular dynamics simulation results of iron (cladding) corrosion in interaction with lead coolant of fast nuclear reactor. The goal of this work is to study effect of oxygen injection to the coolant to reduce iron corrosion. By evaluating diffusion coefficients, radial distribution functions, mean-square displacement curves and observation of crystal structure of iron before and after oxygen injection, we concluded that a significant reduction of corrosion can be achieved by issuing about 2% of oxygen atoms into lead coolant.

  5. Numerical study: Iron corrosion-resistance in lead-bismuth eutectic coolant by molecular dynamics method

    SciTech Connect

    Arkundato, Artoto; Su'ud, Zaki; Abdullah, Mikrajuddin; Widayani,; Celino, Massimo

    2012-06-06

    In this present work, we report numerical results of iron (cladding) corrosion study in interaction with lead-bismuth eutectic coolant of advanced nuclear reactors. The goal of this work is to study how the oxygen can be used to reduce the corrosion rate of cladding. The molecular dynamics method was applied to simulate corrosion process. By evaluating the diffusion coefficients, RDF functions, MSD curves of the iron and also observed the crystal structure of iron before and after oxygen injection to the coolant then we concluded that a significant and effective reduction can be achieved by issuing about 2% number of oxygen atoms to lead-bismuth eutectic coolant.

  6. Thermodynamic Development of Corrosion Rate Modeling in Iron Phosphate Glasses

    SciTech Connect

    Schlesinger, Mark; Brow, Richard

    2011-10-31

    A two-year research program investigated links between the thermodynamic properties of phosphate glasses and their corrosion rates in different solutions. Glasses in the Na2O-CaO-P2O5 and Na2O-Fe2O3-PO5 systems were prepared and characterized. These glasses were then exposed in bulk and powder form to acid (0.1M HCl), basic (0.1M KOH) and neutral (deionized water) solutions at varying exposure times and temperatures. Analysis of the solution and the glass after exposure determined the rate and type of corrosion that occurred. Simultaneously, efforts were made to determine the thermodynamic properties of solid iron phosphate compounds. This included measurement of low temperature (5-300 K) heat capacities, measured at Brigham Young University; the attempted use of a Parr calorimeter to measure ambient temperature enthalpies of formation; and attempted measurement of temperature heat capacities. Only the first of the three tasks was successfully accomplished. In lieu of experimental measurement of enthalpies of formation, first-principles calculation of enthalpies of formation was performed at Missouri S&T; these results will be used in subsequent modeling efforts.

  7. Modeling of corrosion product migration in the secondary circuit of nuclear power plants with WWER-1200

    NASA Astrophysics Data System (ADS)

    Kritskii, V. G.; Berezina, I. G.; Gavrilov, A. V.; Motkova, E. A.; Zelenina, E. V.; Prokhorov, N. A.; Gorbatenko, S. P.; Tsitser, A. A.

    2016-04-01

    Models of corrosion and mass transfer of corrosion products in the pipes of the condensate-feeding and steam paths of the secondary circuit of NPPs with WWER-1200 are presented. The mass transfer and distribution of corrosion products over the currents of the working medium of the secondary circuit were calculated using the physicochemical model of mass transfer of corrosion products in which the secondary circuit is regarded as a cyclic system consisting of a number of interrelated elements. The circuit was divided into calculated regions in which the change in the parameters (flow rate, temperature, and pressure) was traced and the rates of corrosion and corrosion products entrainment, high-temperature pH, and iron concentration were calculated. The models were verified according to the results of chemical analyses at Kalinin NPP and iron corrosion product concentrations in the feed water at different NPPs depending on pH at 25°C (pH25) for service times τ ≥ 5000 h. The calculated pH values at a coolant temperature t (pH t ) in the secondary circuit of NPPs with WWER-1200 were presented. The calculation of the distribution of pH t and ethanolamine and ammonia concentrations over the condensate feed (CFC) and steam circuits is given. The models are designed for developing the calculation codes. The project solutions of ATOMPROEKT satisfy the safety and reliability requirements for power plants with WWER-1200. The calculated corrosion and corrosion product mass transfer parameters showed that the model allows the designer to choose between the increase of the correcting reagent concentration, the use of steel with higher chromium contents, and intermittent washing of the steam generator from sediments as the best solution for definite regions of the circuit.

  8. Iron corrosion activity of anaerobic hydrogen-consuming microorganisms isolated from oil facilities.

    PubMed

    Mori, Koji; Tsurumaru, Hirohito; Harayama, Shigeaki

    2010-10-01

    The purpose of the present study was to test the hypothesis that anaerobic hydrogen-consuming microorganisms generally promote iron corrosion. We isolated 26 hydrogen-consuming microorganisms (acetogens, sulfate-reducing bacteria, and methanogens) from oil facilities in Japan using hydrogen as an electron donor. The iron corrosion activities of these microorganisms were examined using iron (Fe0) granules as the sole electron donor. Almost all the isolates consumed hydrogen that was chemically generated from iron granules but did not induce significant iron corrosion. The amount of corroded iron in the cultures of these organisms was less than 2-fold that in an abiotic chemical corrosion reaction. These results indicated that hydrogen consumption did not strongly stimulate iron corrosion. On the other hand, one isolate, namely, Methanococcus maripaludis Mic1c10, considerably corroded iron: this phenomenon was not accompanied by hydrogen consumption, methane formation, or cell growth. This finding also provided strong evidence that M. maripaludis Mic1c10 produced some material that caused iron to corrode.

  9. Galvanic Corrosion of Lead by Iron (Oxyhydr)Oxides: Potential Impacts on Drinking Water Quality.

    PubMed

    Trueman, Benjamin F; Sweet, Gregory A; Harding, Matthew D; Estabrook, Hayden; Bishop, D Paul; Gagnon, Graham A

    2017-06-20

    Lead exposure via drinking water remains a significant public health risk; this study explored the potential effects of upstream iron corrosion on lead mobility in water distribution systems. Specifically, galvanic corrosion of lead by iron (oxyhydr)oxides was investigated. Coupling an iron mineral cathode with metallic lead in a galvanic cell increased lead release by 531 μg L(-1) on average-a 9-fold increase over uniform corrosion in the absence of iron. Cathodes were composed of spark plasma sintered Fe3O4 or α-Fe2O3 or field-extracted Fe3O4 and α-FeOOH. Orthophosphate immobilized oxidized lead as insoluble hydroxypyromorphite, while humic acid enhanced lead mobility. Addition of a humic isolate increased lead release due to uniform corrosion by 81 μg L(-1) and-upon coupling lead to a mineral cathode-release due to galvanic corrosion by 990 μg L(-1). Elevated lead in the presence of humic acid appeared to be driven by complexation, with (208)Pb and UV254 size-exclusion chromatograms exhibiting strong correlation under these conditions (R(2)average = 0.87). A significant iron corrosion effect was consistent with field data: lead levels after lead service line replacement were greater by factors of 2.3-4.7 at sites supplied by unlined cast iron distribution mains compared with the alternative, lined ductile iron.

  10. Corrosion Mechanisms of Steel and Cast Iron by Molten Aluminum

    NASA Astrophysics Data System (ADS)

    Balloy, David; Tissier, Jean-Charles; Giorgi, Marie-Laurence; Briant, Marc

    2010-09-01

    The corrosion mechanisms by liquid aluminum of three industrial materials have been studied: unalloyed steel (UAS), and ferritic and modified pearlitic cast irons (FCI and PCI, respectively). The behavior of these materials when in contact with liquid aluminum is different. Aluminum diffuses deep into the UAS and forms intermetallic compounds with iron at the surface and in the steel matrix. At the surface, only Fe2Al5 and FeAl3 are found. In the matrix, FeAl2 also is formed in agreement with the equilibrium Fe-Al diagram. From the matrix to FeAl2, the Al content in the ferrite increases progressively until Al saturation is reached. At this step, black elongated precipitates (Al4C3 and/or graphite) appear. Graphite lamellas present in both FCI and PCI constitute an efficient barrier to the Al diffusion. The high silicon content of the FCI leads to the formation of a phase free from Al and saturated in Si. For the PCI, a thin layer rich in Al and Si, which is formed between the matrix and Fe2Al5, limits the diffusion of atoms. The effects of Cr and P added in the PCI also are discussed.

  11. Iron-Based Amorphous Metals: High-Performance Corrosion-Resistant Material Development

    NASA Astrophysics Data System (ADS)

    Farmer, Joseph; Choi, Jor-Shan; Saw, Cheng; Haslam, Jeffrey; Day, Dan; Hailey, Phillip; Lian, Tiangan; Rebak, Raul; Perepezko, John; Payer, Joe; Branagan, Daniel; Beardsley, Brad; D'Amato, Andy; Aprigliano, Lou

    2009-06-01

    An overview of the High-Performance Corrosion-Resistant Materials (HPCRM) Program, which was cosponsored by the Defense Advanced Research Projects Agency (DARPA) Defense Sciences Office (DSO) and the U.S. Department of Energy (DOE) Office of Civilian and Radioactive Waste Management (OCRWM), is discussed. Programmatic investigations have included a broad range of topics: alloy design and composition, materials synthesis, thermal stability, corrosion resistance, environmental cracking, mechanical properties, damage tolerance, radiation effects, and important potential applications. Amorphous alloys identified as SAM2X5 (Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4) and SAM1651 (Fe48Mo14Cr15Y2C15B6) have been produced as meltspun ribbons (MSRs), dropcast ingots, and thermal-spray coatings. Chromium (Cr), molybdenum (Mo), and tungsten (W) additions provided corrosion resistance, while boron (B) enabled glass formation. Earlier electrochemical studies of MSRs and ingots of these amorphous alloys demonstrated outstanding passive film stability. More recently, thermal-spray coatings of these amorphous alloys have been made and subjected to long-term salt-fog and immersion tests; good corrosion resistance has been observed during salt-fog testing. Corrosion rates were measured in situ with linear polarization, while the open-circuit corrosion potentials (OCPs) were simultaneously monitored; reasonably good performance was observed. The sensitivity of these measurements to electrolyte composition and temperature was determined. The high boron content of this particular amorphous metal makes this amorphous alloy an effective neutron absorber and suitable for criticality-control applications. In general, the corrosion resistance of such iron-based amorphous metals is maintained at operating temperatures up to the glass transition temperature. These materials are much harder than conventional stainless steel and Ni-based materials, and are proving to have excellent wear

  12. Iron-Based Amorphous Metals:The High Performance Corrosion Resistant Materials(HPCRM) Program

    SciTech Connect

    Farmer, J

    2007-07-09

    An overview of the High-Performance Corrosion-Resistant Materials (HPCRM) Program, which was co-sponsored by the Defense Advanced Research Projects Agency (DARPA) Defense Sciences Office (DSO) and the United States Department of Energy (DOE) Office of Civilian and Radioactive Waste Management (OCRWM), is discussed. Programmatic investigations have included a broad range of topics: alloy design and composition; materials synthesis; thermal stability; corrosion resistance; environmental cracking; mechanical properties; damage tolerance; radiation effects; and important potential applications. Amorphous alloys identified as SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) and SAM1651 (Fe{sub 48}Mo{sub 14}Cr{sub 15}Y{sub 2}C{sub 15}B{sub 6}) have been produced as melt-spun ribbons, drop-cast ingots and thermal-spray coatings. Chromium (Cr), molybdenum (Mo) and tungsten (W) additions provided corrosion resistance, while boron (B) enabled glass formation. Earlier electrochemical studies of melt-spun ribbons and ingots of these amorphous alloys demonstrated outstanding passive film stability. More recently thermal-spray coatings of these amorphous alloys have been made and subjected to long-term salt-fog and immersion tests. Good corrosion resistance has been observed during salt-fog testing. Corrosion rates were measured in situ with linear polarization, while simultaneously monitoring the open-circuit corrosion potentials. Reasonably good performance was observed. The sensitivity of these measurements to electrolyte composition and temperature was determined. The high boron content of this particular amorphous metal makes this amorphous alloy an effective neutron absorber, and suitable for criticality control applications. In general, the corrosion resistance of such iron-based amorphous metals is maintained at operating temperatures up to the glass transition temperature. These materials are much harder than conventional

  13. Iron-Based Amorphous-Metals: High-Performance Corrosion-Resistant Material (HPCRM) Development

    SciTech Connect

    Farmer, J C; Choi, J S; Saw, C; Haslam, J; Day, D; Hailey, P; Lian, T; Rebak, R; Perepezko, J; Payer, J; Branagan, D; Beardsley, B; D'Amato, A; Aprigliano, L

    2008-01-09

    An overview of the High-Performance Corrosion-Resistant Materials (HPCRM) Program, which was co-sponsored by the Defense Advanced Research Projects Agency (DARPA) Defense Sciences Office (DSO) and the United States Department of Energy (DOE) Office of Civilian and Radioactive Waste Management (OCRWM), is discussed. Programmatic investigations have included a broad range of topics: alloy design and composition; materials synthesis; thermal stability; corrosion resistance; environmental cracking; mechanical properties; damage tolerance; radiation effects; and important potential applications. Amorphous alloys identified as SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) and SAM1651 (Fe{sub 48}Mo{sub 14}Cr{sub 15}Y{sub 2}C{sub 15}B{sub 6}) have been produced as melt-spun ribbons, drop-cast ingots and thermal-spray coatings. Chromium (Cr), molybdenum (Mo) and tungsten (W) additions provided corrosion resistance, while boron (B) enabled glass formation. Earlier electrochemical studies of melt-spun ribbons and ingots of these amorphous alloys demonstrated outstanding passive film stability. More recently thermal-spray coatings of these amorphous alloys have been made and subjected to long-term salt-fog and immersion tests. Good corrosion resistance has been observed during salt-fog testing. Corrosion rates were measured in situ with linear polarization, while simultaneously monitoring the open-circuit corrosion potentials. Reasonably good performance was observed. The sensitivity of these measurements to electrolyte composition and temperature was determined. The high boron content of this particular amorphous metal makes this amorphous alloy an effective neutron absorber, and suitable for criticality control applications. In general, the corrosion resistance of such iron-based amorphous metals is maintained at operating temperatures up to the glass transition temperature. These materials are much harder than conventional

  14. Mechanism for Corrosion Prevention by a Mechanical Plating of Uniform Zinc-Iron Alloy

    NASA Astrophysics Data System (ADS)

    Kasai, Naoya; Kaku, Yoshihiko; Okazaki, Shinji; Hirai, Kuninori

    2016-11-01

    In situ electrochemical monitoring with a three-electrode cell was applied to investigate the anti-corrosion properties of a mechanical zinc-iron alloy plating. Several electron probe microanalyses were also conducted to identify the chemical elements in the plating. The results indicated the formation of a Zn-Fe intermetallic compound, which allowed a mechanism for corrosion prevention to be proposed. In the proposed mechanism, Zn(OH)2 plays a significant role in the corrosion prevention of steel alloys.

  15. Effects of 1000 C oxide surfaces on room temperature aqueous corrosion and environmental embrittlement of iron aluminides

    SciTech Connect

    Buchanan, R.A.; Perrin, R.L.

    1997-12-01

    Results of electrochemical aqueous-corrosion studies at room temperature indicate that retained in-service-type high-temperature surface oxides (1000 C in air for 24 hours) on FA-129, FAL and FAL-Mo iron aluminides cause major reductions in pitting corrosion resistance in a mild acid-chloride solution designed to simulate aggressive atmospheric corrosion. Removal of the oxides by mechanical grinding restores the corrosion resistance. In a more aggressive sodium tetrathionate solution, designed to simulate an aqueous environment contaminated by sulfur-bearing combustion products, only active corrosion occurs for both the 1000 C oxide and mechanically cleaned surfaces at FAL. Results of slow-strain-rate stress-corrosion-cracking tests on FA-129, FAL and FAL-Mo at free-corrosion and hydrogen-charging potentials in the mild acid chloride solution indicate somewhat higher ductilities (on the order of 50%) for the 1000 C oxides retard the penetration of hydrogen into the metal substrates and, consequently, are beneficial in terms of improving resistance to environmental embrittlement. In the aggressive sodium tetrathionate solution, no differences are observed in the ductilities produced by the 1000 C oxide and mechanically cleaned surfaces for FAL.

  16. Corrosion studies of iron and its alloys by means of57Fe Mössbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Marco, J. F.; Dávalos, J.; Gracia, M.; Gancedo, J. R.

    1994-12-01

    Some of the advantages and limitations of Mössbauer spectroscopy when used in corrosion research are shown by using three examples taken from the work of the authors on (i) the passive layer of iron, (ii) the corrosion of weathering steels by SO2-polluted atmospheres and (iii) the performance of rust converters.

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

    NASA Astrophysics Data System (ADS)

    Nakanishi, A.

    2012-03-01

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

  18. Correlation of 2-chlorobiphenyl dechlorination by Fe/Pd with iron corrosion at different pH.

    PubMed

    Fang, Yuanxiang; Al-Abed, Souhail R

    2008-09-15

    The rate of 2-chlorobiphenyl dechlorination by palladized iron (Fe/ Pd) decreased with increasing pH until pH > 12.5. Iron corrosion potential (Ec) and current (jc), obtained from polarization curves of a rotating disk electrode of iron, followed the Tafel equation at pH < or = 5.5 and pH > or = 9.5. The pH dependence of the dechlorination rate constant (k1) suggests four pH regimes. In the low pH regime (3-5.5), /Ec/ and je decreased with increasing pH and k1 was linearly correlated to /Ec/ and jc0.5. The correlation between k1 and jc0.5 indicates direct involvement of active hydrogen species (on the Pd surface) in PCB dechlorination. In the mid pH regime (5.5-9.5), no significant effect of pH was evident on the values of k1, je, and Ec, a combined result of limiting anodic oxidation of iron to an intermediate product (iron hydroxide) and a proton-independent overall reaction. Both /Ec/ and jc increased significantly as pH increased from 9.5 to 14. A cleartrough of the k1 values in solutions of pH between 12 and 13 and the mismatch between the kinetic and corrosion data suggest two pH regimes (9.5-12.5 and 12.5-14) of different corrosion mechanisms.

  19. Drying characteristics of thorium fuel corrosion products

    NASA Astrophysics Data System (ADS)

    Smith, R.-E. Lords

    2004-07-01

    The open literature and accessible US Department of Energy-sponsored reports were reviewed for the dehydration and rehydration characteristics of potential corrosion products from thorium metal and thorium oxide nuclear fuels. Mixed oxides were not specifically examined unless data were given for performance of mixed thorium-uranium fuels. Thorium metal generally corrodes to thorium oxide. Physisorbed water is readily removed by heating to approximately 200 °C. Complete removal of chemisorbed water requires heating above 1000 °C. Thorium oxide adsorbs water well in excess of the amount needed to cover the oxide surface by chemisorption. The adsorption of water appears to be a surface phenomenon; it does not lead to bulk conversion of the solid oxide to the hydroxide. Adsorptive capacity depends on both the specific surface area and the porosity of the thorium oxide. Heat treatment by calcination or sintering reduces the adsorption capacity substantially from the thorium oxide produced by metal corrosion.

  20. Behavior of tritium permeation induced by water corrosion of alpha iron around room temperature

    SciTech Connect

    Otsuka, T.; Hashizume, K.

    2015-03-15

    Tritium (T) permeation leakage to surroundings is a great safety concern in fission and fusion reactor systems. T permeation potentially occurs from T contaminated water through cooling tubes or storage tank made of metals which dissolve some T evolved by water corrosion. In order to understand behaviors of hydrogen uptake and permeation in pure α-iron (αFe) during water corrosion around room temperature, hydrogen permeation experiments for an αFe membrane have been conducted by means of tritium tracer techniques. The present study suggests that hydrogen produced by water corrosion of αFe is trapped in product oxide layers to delay hydrogen uptake in αFe for a moment. However, the oxide layers do not work as a sufficient barrier for hydrogen uptake. Some of hydrogen dissolved in αFe normally diffuses and permeates through the bulk in the early stage of permeation. In a later stage, hydrogen permeation could be apparently stopped by the disappearance of concentration difference of tritium. Hydrogen partial pressure at the water/αFe interface could be ranged from 0.7 to 9.5 kPa around room temperature.

  1. Mössbauer study of the corrosion behaviour of pure iron and weathering steel under a wet-dry cycle

    NASA Astrophysics Data System (ADS)

    Marco, J. F.; Dávalos, J.; Gancedo, J. R.; Gracia, M.

    1989-03-01

    Mossbauer spectroscopy (MBS) and X-ray diffraction (XRD) have been used to establish the composition of the rust layer formed on weathering steel and pure iron under several wet-dry cycles in a SO2-polluted atmosphere. FeSO3-3H2O, FeSO4-4H2O, and poorly crystalline ferrihydrite were identified as the only corrosion products. The Mossbauer spectrum of FeSO3-3H2O is reported.

  2. Molecular dynamics simulation of corrosion mitigation of iron in lead-bismuth eutectic using nitrogen as corrosion inhibitor

    NASA Astrophysics Data System (ADS)

    Arkundato, Artoto; Su'ud, Zaki; Sudarko; Hasan, Mohammad; Celino, Massimo

    2015-06-01

    The corrosion of structural materials used in fast nuclear reactor design is a current major problem. It is due to the use of liquid metal as a coolant candidate in the heat transfer system. The liquid metal as lead-bismuth eutectic was found to make high corrosion to structural material as steel. One of the solutions of this problem is to inject some inhibitor into liquid metal. In this current work we simulate the effect of nitrogen injection as inhibitor candidate. The simulation will predict the proper concentration of injected nitrogen and also observe the microscopic structure of the material before and after injection to know the ability of nitrogen as an inhibitor. The simulation follows the molecular dynamics method and for preliminary study we use iron material rather than steel. We also use lennard-jones potential for simplification of the study. It is from our simulation we see nitrogen shows better corrosion mitigation compare with oxygen as in our previous study. The effective inhibition can be achieved by injecting at least 0.056wt.% nitrogen. This amount seems to be able to reduce the corrosion level of iron till about 99.5% for high corrosion at temperature 750 °C.

  3. Impact of iron-reducing bacteria on the corrosion rate of carbon steel under simulated geological disposal conditions.

    PubMed

    Schütz, Marta K; Schlegel, Michel L; Libert, Marie; Bildstein, Olivier

    2015-06-16

    The current projects for the disposal of high-level radioactive waste rely on underground burial and confinement by metallic envelopes that are susceptible to corrosion processes. The impact of microbial activity must be fully clarified in order to provide biological parameters for predictive reactive transport models. This study investigates the impact of hydrogenotrophic iron-reducing bacteria (Shewanella oneidensis strain MR-1) on the corrosion rate of carbon steel under simulated geological disposal conditions by using a geochemical approach. It was found that corrosion damage changes mostly according to the experimental solution (i.e., chemical composition). Magnetite and vivianite were identified as the main corrosion products. In the presence of bacteria, the corrosion rate increased by a factor of 1.3 (according to weight loss analysis) to 1.8 (according to H2 measurements), and the detected amount of magnetite diminished. The mechanism likely to enhance corrosion is the destabilization and dissolution of the passivating magnetite layer by reduction of structural Fe(III) coupled to H2 oxidation.

  4. 21 CFR 310.518 - Drug products containing iron or iron salts.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 5 2012-04-01 2012-04-01 false Drug products containing iron or iron salts. 310... Drug products containing iron or iron salts. Drug products containing elemental iron or iron salts as...) that contains iron or iron salts for use as an iron source shall bear the following statement: WARNING...

  5. 21 CFR 310.518 - Drug products containing iron or iron salts.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Drug products containing iron or iron salts. 310... Drug products containing iron or iron salts. Drug products containing elemental iron or iron salts as...) that contains iron or iron salts for use as an iron source shall bear the following statement: WARNING...

  6. 21 CFR 310.518 - Drug products containing iron or iron salts.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 5 2011-04-01 2011-04-01 false Drug products containing iron or iron salts. 310... Drug products containing iron or iron salts. Drug products containing elemental iron or iron salts as...) that contains iron or iron salts for use as an iron source shall bear the following statement: WARNING...

  7. 21 CFR 310.518 - Drug products containing iron or iron salts.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 5 2014-04-01 2014-04-01 false Drug products containing iron or iron salts. 310... Drug products containing iron or iron salts. Drug products containing elemental iron or iron salts as...) that contains iron or iron salts for use as an iron source shall bear the following statement: WARNING...

  8. 21 CFR 310.518 - Drug products containing iron or iron salts.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 5 2013-04-01 2013-04-01 false Drug products containing iron or iron salts. 310... Drug products containing iron or iron salts. Drug products containing elemental iron or iron salts as...) that contains iron or iron salts for use as an iron source shall bear the following statement: WARNING...

  9. In vitro corrosion, cytotoxicity and hemocompatibility of bulk nanocrystalline pure iron.

    PubMed

    Nie, F L; Zheng, Y F; Wei, S C; Hu, C; Yang, G

    2010-12-01

    Bulk nanocrystalline pure iron rods were fabricated by the equal channel angular pressure (ECAP) technique up to eight passes. The microstructure and grain size distribution, natural immersion and electrochemical corrosion in simulated body fluid, cellular responses and hemocompatibility were investigated in this study. The results indicate that nanocrystalline pure iron after severe plastic deformation (SPD) would sustain durable span duration and exhibit much stronger corrosion resistance than that of the microcrystalline pure iron. The interaction of different cell lines reveals that the nanocrystalline pure iron stimulates better proliferation of fibroblast cells and preferable promotion of endothelialization, while inhibits effectively the viability of vascular smooth muscle cells (VSMCs). The burst of red cells and adhesion of the platelets were also substantially suppressed on contact with the nanocrystalline pure iron in blood circulation. A clear size-dependent behavior from the grain nature deduced by the gradual refinement microstructures was given and well-behaved in vitro biocompatibility of nanocrystalline pure iron was concluded.

  10. OSCAR-Na: A New Code for Simulating Corrosion Product Contamination in SFR

    NASA Astrophysics Data System (ADS)

    Génin, J.-B.; Brissonneau, L.; Gilardi, T.

    2016-12-01

    A code named OSCAR-Na has been developed to calculate the mass transfer of corrosion products in the primary circuit of sodium fast reactors (SFR). It is based on a solution/precipitation model, including diffusion in the steel (enhanced under irradiation), diffusion through the sodium boundary layer, equilibrium concentration of each element, and velocity of the interface (bulk corrosion or deposition). The code uses a numerical method for solving the diffusion equation in the steel and the complete mass balance in sodium for all elements. Corrosion and deposition rates are mainly determined by the iron equilibrium concentration in sodium and its oxygen-enhanced dissolution rate. All parameters of the model have been assessed from a literature review, but iron solubility had to be adjusted. A simplified primary system description of PHENIX French SFR was able to assess the correct amounts and profiles of contamination on heat exchanger surfaces for the main radionuclides.

  11. Vacuum ultraviolet fluorine laser formation of corrosion-resistant iron thin films

    NASA Astrophysics Data System (ADS)

    Okoshi, Masayuki; Awaihara, Yuta; Yamashita, Tsugito; Inoue, Narumi

    2015-06-01

    Corrosion-, chemical-resistant pure iron thin films were formed by the vacuum ultraviolet fluorine laser of 157 nm wavelength induced surface modification of 30- to 50-nm-thick iron thin films. Transmission electron microscope and electron energy-loss spectroscopy were conducted to analyze structure and oxidation state of the thin modified layer of iron thin films. No rust was observed on the surface of the fluorine laser-irradiated iron thin films in air for 2 years. The samples also showed high chemical resistance to a HNO3 aqueous solution to fabricate a micropattern of pure iron thin films.

  12. Erosion-corrosion behavior of austenitic cast iron in an acidic slurry medium

    NASA Astrophysics Data System (ADS)

    Yang, Ke; Sun, Lan; Liu, Yu-zhen; Fan, Hong-yuan

    2015-06-01

    A series of austenitic cast iron samples with different compositions were cast and a part of nickel in the samples was replaced by manganese for economic reason. Erosion-corrosion tests were conducted under 2wt% sulfuric acid and 15wt% quartz sand. The results show that the matrix of cast irons remains austenite after a portion of nickel is replaced with manganese. (Fe,Cr)3C is a common phase in the cast irons, and nickel is the main alloying element in high-nickel cast iron; whereas, (Fe,Mn)3C is observed with the increased manganese content in low-nickel cast iron. Under erosion-corrosion tests, the weight-loss rates of the cast irons increase with increasing time. Wear plays a more important role than corrosion in determining the weight loss. It is indicated that the processes of weight loss for the cast irons with high and low nickel contents are different. The erosion resistance of the cast iron containing 7.29wt% nickel and 6.94wt% manganese is equivalent to that of the cast iron containing 13.29wt% nickel.

  13. ALKALINITY, PH, AND COPPER CORROSION BY-PRODUCT RELEASE

    EPA Science Inventory

    Contrary to expectations, higher bicarbonate concentrations exacerbate copper corrosion rates and by-product release. In fact, as illustrated by monitoring experiences of large utilities and by laboratory data, the concentration of copper corrosion by-products in drinking water i...

  14. ALKALINITY, PH, AND COPPER CORROSION BY-PRODUCT RELEASE

    EPA Science Inventory

    Contrary to expectations, higher bicarbonate concentrations exacerbate copper corrosion rates and by-product release. In fact, as illustrated by monitoring experiences of large utilities and by laboratory data, the concentration of copper corrosion by-products in drinking water i...

  15. The corrosion inhibition of iron and aluminum by various naturally occurring biological molecules

    SciTech Connect

    McCafferty, E.; Hansen, D.C.

    1995-12-31

    Biological polymers that exhibit a strong affinity for metal surfaces are increasingly becoming the focus of research toward the development of environmentally friendly corrosion inhibitors. This paper deals with the use of various naturally occurring organic molecules as corrosion inhibitors for iron or aluminum. Among the organic molecules considered are catecholate and hydroxamate siderophores isolated from bacteria, the adhesive protein from the blue mussel Mytilus edulis L, and caffeic acid and chlorogenic acid. FTIR analysis, anodic polarization curves, and AC impedance measurements were used to determine the adsorption and effectiveness of the various organic molecules as corrosion inhibitors. Parabactin, a catecholate siderophore, was effective in inhibiting both the corrosion of iron in hydrochloric acid and the pitting of aluminum in 0.1 M sodium chloride. The adhesive protein from the blue mussel was also effective in inhibiting the pitting of aluminum.

  16. Corrosion Inhibition of Cast Iron in Arabian Gulf Seawater by Two Different Ionic Liquids

    PubMed Central

    Sherif, El-Sayed M.; Abdo, Hany S.; Zein El Abedin, Sherif

    2015-01-01

    In this paper we report on the corrosion inhibition of cast iron in Arabian Gulf seawater by two different ionic liquids namely, 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl) and 1-butyl-1-methylpyrrolidinium chloride ([Py1,4]Cl). The inhibiting influence of the employed ionic liquids was investigated by weight loss, open circuit potential electrochemical impedance spectroscopy, and cyclic potentiodynamic polarization. The results show the corrosion inhibition impact of the employed ionic liquids (ILs). Compared with [Py1,4]Cl, [EMIm]Cl shows a higher inhibition efficiency at a short immersion time, for the examined ILs concentrations. However, [Py1,4]Cl exhibits a higher efficiency upon increasing the immersion time indicating the persistence of the inhibiting influence. The corrosion inhibition of the employed ionic liquids is attributed to the adsorption of the cations of the ionic liquids onto the surface of cast iron forming a corrosion barrier. PMID:28793413

  17. Application of Mössbauer spectroscopy to the study of tannins inhibition of iron and steel corrosion

    NASA Astrophysics Data System (ADS)

    Jaén, Juan A.; de Obaldía, J.; Rodríguez, M. V.

    2011-11-01

    The inhibitory effect of tannins was investigated using, among others, potentiodynamic polarizations and Mössbauer spectroscopy. These techniques confirmed that the nature, pH and concentration of tannic solution are of upmost importance in the inhibitory properties of the solutions. It is observed that at low tannin concentration or pH, both, hydrolizable and condensed tannins, effectively inhibit iron corrosion, due to the redox properties of tannins. At pH ≈ 0, Mössbauer spectra of the frozen aqueous solutions of iron(III) with the tannin solutions showed that iron is in the form of a monomeric species [Fe(H2O)6]3 + , without coordination with the functional hydroxyl groups of the tannins. The suspended material consisted of amorphous ferric oxide and oxyhydroxides, though with quebracho tannin partly resulted in complex formation and in an iron (II) species from a redox process. Other tannins, such as chestnut hydrolysable tannins, do not complex iron at this low pH. Tannins react at high concentrations or pH (3 and 5) to form insoluble blue-black amorphous complexes of mono-and bis-type tannate complexes, with a relative amount of the bis-ferric tannate generally increasing with pH. Some Fe2 + in the form of hydrated polymeric ferrous tannate could be obtained. At pH 7, a partially hydrolyzed ferric tannate complex was also formed. The latter two phases do not provide corrosion protection. Tannin solutions at natural pH react with electrodeposited iron films (approx. 6 μm) to obtain products consisting only on the catecholate mono-complex of ferric tannate. Some aspects of the mechanism of tannins protection against corrosion are discussed.

  18. In vitro and in vivo corrosion properties of new iron-manganese alloys designed for cardiovascular applications.

    PubMed

    Drynda, Andreas; Hassel, Thomas; Bach, Friedrich Wilhelm; Peuster, Matthias

    2015-04-01

    The principle of biodegradation for the production of temporary implant materials (e.g. stents) plays an important role in the treatment of congenital heart defects. In the last decade several attempts have been made with different alloy materials-mainly based on iron and magnesium. None of the currently available materials in this field have demonstrated satisfying results and have therefore not found entry into broad clinical practice. While magnesium or magnesium alloy systems corrode too fast, the corrosion rate of pure iron-stents is too slow for cardiovascular applications. In the last years FeMn alloy systems were developed with the idea that galvanic effects, caused by different electrochemical properties of Fe and Mn, would increase the corrosion rate. In vitro tests with alloys containing up to 30% Mn showed promising results in terms of biocompatibility. This study deals with the development of new FeMn alloy systems with lower Mn concentrations (FeMn 0.5 wt %, FeMn 2.7 wt %, FeMn 6.9 wt %) to avoid Mn toxicity. Our results show, that these alloys exhibit good mechanical features as well as suitable in vitro biocompatibility and corrosion properties. In contrast, the evaluation of these alloys in a mouse model led to unexpected results-even after 9 months no significant corrosion was detectable. Preliminary SEM investigations showed that passivation layers (FeMn phosphates) might be the reason for corrosion resistance. If this can be proved in further experiments, strategies to prevent or dissolve those layers need to be developed to expedite the in vivo corrosion of FeMn alloys.

  19. Iron-based alloys with corrosion resistance to oxygen-sulfur mixed gases

    DOEpatents

    Natesan, K.

    1992-11-17

    An iron-based alloy with improved performance with exposure to oxygen-sulfur mixed gases with the alloy containing about 9--30 wt. % Cr and a small amount of Nb and/or Zr implanted on the surface of the alloy to diffuse a depth into the surface portion, with the alloy exhibiting corrosion resistance to the corrosive gases without bulk addition of Nb and/or Zr and without heat treatment at temperatures of 1000--1100 C. 7 figs.

  20. Iron-based alloys with corrosion resistance to oxygen-sulfur mixed gases

    DOEpatents

    Natesan, Krishnamurti

    1992-01-01

    An iron-based alloy with improved performance with exposure to oxygen-sulfur mixed gases with the alloy containing about 9-30 wt. % Cr and a small amount of Nb and/or Zr implanted on the surface of the alloy to diffuse a depth into the surface portion, with the alloy exhibiting corrosion resistance to the corrosive gases without bulk addition of Nb and/or Zr and without heat treatment at temperatures of 1000.degree.-1100.degree. C.

  1. Marine sulfate-reducing bacteria cause serious corrosion of iron under electroconductive biogenic mineral crust.

    PubMed

    Enning, Dennis; Venzlaff, Hendrik; Garrelfs, Julia; Dinh, Hang T; Meyer, Volker; Mayrhofer, Karl; Hassel, Achim W; Stratmann, Martin; Widdel, Friedrich

    2012-07-01

    Iron (Fe(0) ) corrosion in anoxic environments (e.g. inside pipelines), a process entailing considerable economic costs, is largely influenced by microorganisms, in particular sulfate-reducing bacteria (SRB). The process is characterized by formation of black crusts and metal pitting. The mechanism is usually explained by the corrosiveness of formed H(2) S, and scavenge of 'cathodic' H(2) from chemical reaction of Fe(0) with H(2) O. Here we studied peculiar marine SRB that grew lithotrophically with metallic iron as the only electron donor. They degraded up to 72% of iron coupons (10 mm × 10 mm × 1 mm) within five months, which is a technologically highly relevant corrosion rate (0.7 mm Fe(0) year(-1) ), while conventional H(2) -scavenging control strains were not corrosive. The black, hard mineral crust (FeS, FeCO(3) , Mg/CaCO(3) ) deposited on the corroding metal exhibited electrical conductivity (50 S m(-1) ). This was sufficient to explain the corrosion rate by electron flow from the metal (4Fe(0)  → 4Fe(2+)  + 8e(-) ) through semiconductive sulfides to the crust-colonizing cells reducing sulfate (8e(-)  + SO(4) (2-)  + 9H(+)  → HS(-)  + 4H(2) O). Hence, anaerobic microbial iron corrosion obviously bypasses H(2) rather than depends on it. SRB with such corrosive potential were revealed at naturally high numbers at a coastal marine sediment site. Iron coupons buried there were corroded and covered by the characteristic mineral crust. It is speculated that anaerobic biocorrosion is due to the promiscuous use of an ecophysiologically relevant catabolic trait for uptake of external electrons from abiotic or biotic sources in sediments.

  2. Marine sulfate-reducing bacteria cause serious corrosion of iron under electroconductive biogenic mineral crust

    PubMed Central

    Enning, Dennis; Venzlaff, Hendrik; Garrelfs, Julia; Dinh, Hang T; Meyer, Volker; Mayrhofer, Karl; Hassel, Achim W; Stratmann, Martin; Widdel, Friedrich

    2012-01-01

    Iron (Fe0) corrosion in anoxic environments (e.g. inside pipelines), a process entailing considerable economic costs, is largely influenced by microorganisms, in particular sulfate-reducing bacteria (SRB). The process is characterized by formation of black crusts and metal pitting. The mechanism is usually explained by the corrosiveness of formed H2S, and scavenge of ‘cathodic’ H2 from chemical reaction of Fe0 with H2O. Here we studied peculiar marine SRB that grew lithotrophically with metallic iron as the only electron donor. They degraded up to 72% of iron coupons (10 mm × 10 mm × 1 mm) within five months, which is a technologically highly relevant corrosion rate (0.7 mm Fe0 year−1), while conventional H2-scavenging control strains were not corrosive. The black, hard mineral crust (FeS, FeCO3, Mg/CaCO3) deposited on the corroding metal exhibited electrical conductivity (50 S m−1). This was sufficient to explain the corrosion rate by electron flow from the metal (4Fe0 → 4Fe2+ + 8e−) through semiconductive sulfides to the crust-colonizing cells reducing sulfate (8e− + SO42− + 9H+ → HS− + 4H2O). Hence, anaerobic microbial iron corrosion obviously bypasses H2 rather than depends on it. SRB with such corrosive potential were revealed at naturally high numbers at a coastal marine sediment site. Iron coupons buried there were corroded and covered by the characteristic mineral crust. It is speculated that anaerobic biocorrosion is due to the promiscuous use of an ecophysiologically relevant catabolic trait for uptake of external electrons from abiotic or biotic sources in sediments. PMID:22616633

  3. Iron production maintenance effectiveness system

    SciTech Connect

    Augstman, J.J.

    1996-12-31

    In 1989, an internal study in the Coke and Iron Maintenance Department identified the opportunities available to increase production, by decreasing unscheduled maintenance delays from 4.6%. A five year front loaded plan was developed, and presented to the company president. The plan required an initial investment of $1.4 million and a conservative break-even point was calculated to be 2.5 years. Due to budget restraints, it would have to be self-funded, i.e., generate additional production or savings, to pay for the program. The program began in 1991 at number 2 coke plant and the blast furnaces. This paper will describe the Iron Production Maintenance Effectiveness System (ME), which began with the mechanical and pipefitting trades.

  4. Development and Testing of a Linear Polarization Resistance Corrosion Rate Probe for Ductile Iron Pipe (Web Report 4361)

    EPA Science Inventory

    The North American water and wastewater community has hundreds of millions of feet of ductile iron pipe in service. Only a portion of the inventory has any form of external corrosion control. Ductile iron pipe, in certain environments, is subject to external corrosion.Linear Pola...

  5. Development and Testing of a Linear Polarization Resistance Corrosion Rate Probe for Ductile Iron Pipe (Web Report 4361)

    EPA Science Inventory

    The North American water and wastewater community has hundreds of millions of feet of ductile iron pipe in service. Only a portion of the inventory has any form of external corrosion control. Ductile iron pipe, in certain environments, is subject to external corrosion.Linear Pola...

  6. Effect of High Temperature Aging on the Corrosion Resistance of Iron Based Amorphous Alloys

    SciTech Connect

    Day, S D; Haslam, J J; Farmer, J C; Rebak, R B

    2007-08-10

    Iron-based amorphous alloys can be more resistant to corrosion than polycrystalline materials of similar compositions. However, when the amorphous alloys are exposed to high temperatures they may recrystallize (or devitrify) thus losing their resistance to corrosion. Four different types of amorphous alloys melt spun ribbon specimens were exposed to several temperatures for short periods of time. The resulting corrosion resistance was evaluated in seawater at 90 C and compared with the as-prepared ribbons. Results show that the amorphous alloys can be exposed to 600 C for 1-hr. without losing the corrosion resistance; however, when the ribbons were exposed at 800 C for 1-hr. their localized corrosion resistance decreased significantly.

  7. Corrosion resistance and electrochemical potentiokinetic reactivation testing of some iron-base hardfacing alloys

    SciTech Connect

    Cockeram, B.V.

    1999-11-01

    Hardfacing alloys are weld deposited on a base material to provide a wear resistant surface. Commercially available iron-base hardfacing alloys are being evaluated for replacement of cobalt-base alloys to reduce nuclear plant activation levels. Corrosion testing was used to evaluate the corrosion resistance of several iron-base hardfacing alloys in highly oxygenated environments. The corrosion test results indicate that iron-base hardfacing alloys in the as-deposited condition have acceptable corrosion resistance when the chromium to carbon ratio is greater than 4. Tristelle 5183, with a high niobium (stabilizer) content, did not follow this trend due to precipitation of niobium-rich carbides instead of chromium-rich carbides. This result indicates that iron-base hardfacing alloys containing high stabilizer contents may possess good corrosion resistance with Cr:C < 4. NOREM 02, NOREM 01, and NoCo-M2 hardfacing alloys had acceptable corrosion resistance in the as-deposited and 885 C/4 hour heat treated condition, but rusting from sensitization was observed in the 621 C/6 hour heat treated condition. The feasibility of using an Electrochemical Potentiokinetic Reactivation (EPR) test method, such as used for stainless steel, to detect sensitization in iron-base hardfacing alloys was evaluated. A single loop-EPR method was found to provide a more consistent measurement of sensitization than a double loop-EPR method. The high carbon content that is needed for a wear resistant hardfacing alloy produces a high volume fraction of chromium-rich carbides that are attacked during EPR testing. This results in inherently lower sensitivity for detection of a sensitized iron-base hardfacing alloy than stainless steel using conventional EPR test methods.

  8. Corrosion Characterization of Iron-Based High-Performance Amorphous-Metal Thermal-Spray Coatings

    SciTech Connect

    Farmer, J C; Haslam, J J; Day, S D; Branagan, D J; Blue, C A; Rivard, J K; Aprigliano, L F; Yang, N; Perepezko, J H; Beardsley, M B

    2005-03-21

    New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. One of these compositions, SAM1651, is discussed in detail to illustrate the promise of this general class of materials.

  9. Corrosion Behavior of Cast Iron in Freely Aerated Stagnant Arabian Gulf Seawater

    PubMed Central

    Sherif, El-Sayed M.; Abdo, Hany S.; Almajid, Abdulhakim A.

    2015-01-01

    In this work, the results obtained from studying the corrosion of cast iron in freely aerated stagnant Arabian Gulf seawater (AGS) at room temperature were reported. The study was carried out using weight-loss (WL), cyclic potentiodynamic polarization (CPP), open-circuit potential (OCP), and electrochemical impedance spectroscopy (EIS) measurements and complemented by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) investigations. WL experiments between two and 10 days’ immersion in the test electrolyte indicated that the weight-loss the cast iron increases with increasing the time of immersion. CPP measurements after 1 h and 24 h exposure period showed that the increase of time decreases the corrosion via decreasing the anodic and cathodic currents, as well as decreasing the corrosion current and corrosion rate and increasing the polarization resistance of the cast iron. EIS data confirmed the ones obtained by WL and CPP that the increase of immersion time decreases the corrosion of cast iron by increasing its polarization resistance.

  10. Effects of Copper and Austempering on Corrosion Behavior of Ductile Iron in 3.5 Pct Sodium Chloride

    NASA Astrophysics Data System (ADS)

    Hsu, Cheng-Hsun; Lin, Kuan-Ting

    2013-10-01

    Although alloying and heat treatments are common industrial practices to obtain ductile irons with desired mechanical properties, related information on how the two practices affect corrosion behavior is scarce. In this study, two ductile irons—with and without 1 wt pct copper addition—were austempered to obtain austempered ductile irons (ADIs). Polarization tests and salt spray tests were conducted to explore how both copper-alloying and austempering heat treatments influenced the corrosion behavior of ductile irons. The results showed that the corrosion resistance of 1 wt pct copper-alloyed ductile iron was better than that of the unalloyed one, while ADI had improved corrosion resistance compared with the as-cast. In particular, the ductile iron combined with the copper-alloying and austempering treatments increased the corrosion inhibition efficiency up to 84 pct as tested in 3.5 wt pct NaCl solution.

  11. [Effect of biofilm on the corrosion and fouling of cast iron pipe for water supply].

    PubMed

    Teng, Fei; Guan, Yun-Tao; Li, Sha-Sha; Zhu, Wan-Peng

    2009-02-15

    The crystalline phase and the element composition in the scales on cast iron pipe for drinking water was identified with XRD and XPS respectively to investigate the effect of biofilm existence on the corrosion and fouling of cast iron pipe. The total iron concentration in the water phase was measured simultaneously. The results showed that on 0-7 d the total iron concentration was higher in the water phase of the group with biofilm growth, but on 15-30 d it was higher in the water phase of the control without biofilm growth. The major peak of XRD patterns for the scales with biofilm growth was characterized as Fe oxide, while for the scales in the control it was always characterized as CaCO3. As presented by XPS atomic ratio, the Ca atomic percentage in the scales with biofilm growth was lower than that in the scales in the control, which might be contributed to the Ca2+ absorption by extracellular polymeric substances or Ca2+ consumption by microorganism growth. In comparison with that in the scales in the control, the iron atomic percentage in the scales with biofilm growth was higher on 7 d, while lower after 7 d. It can be concluded that on 0-7 d the existence of biofilm could promote the corrosion of cast iron pipe while inhibit corrosion after 7 d. The variance of major peak of XRD pattern and XPS atomic ratio indicated that biofilm had important effect on the configuration and composition of the scales of cast iron pipe. The corrosion inhibition of biofilm thus provided a new pathway to control the corrosion of metal pipes in drinking water distribution system.

  12. Effects of the Exposure to Corrosive Salts on the Frictional Behavior of Gray Cast Iron and a Titanium-Based Metal Matrix Composite

    SciTech Connect

    Blau, Peter Julian; Truhan, Jr., John J; Kenik, Edward A

    2007-01-01

    The introduction of increasingly aggressive road-deicing chemicals has created significant and costly corrosion problems for the trucking industry. From a tribological perspective, corrosion of the sliding surfaces of brakes after exposure to road salts can create oxide scales on the surfaces that affect friction. This paper describes experiments on the effects of exposure to sodium chloride and magnesium chloride sprays on the transient frictional behavior of cast iron and a titanium-based composite sliding against a commercial brake lining material. Corrosion scales on cast iron initially act as abrasive third-bodies, then they become crushed, spread out, and behave as a solid lubricant. The composition and subsurface microstructures of the corrosion products on the cast iron were analyzed. Owing to its greater corrosion resistance, the titanium composite remained scale-free and its frictional response was markedly different. No corrosion scales were formed on the titanium composite after aggressive exposure to salts; however, a reduction in friction was still observed. Unlike the crystalline sodium chloride deposits that tended to remain dry, hygroscopic magnesium chloride deposits absorbed ambient moisture from the air, liquefied, and retained a persistent lubricating effect on the titanium surfaces.

  13. Corrosion and environmental-mechanical characterization of iron-base nuclear waste package structural barrier materials. Annual report, FY 1984

    SciTech Connect

    Westerman, R.E.; Haberman, J.H.; Pitman, S.G.; Pulsipher, B.A.; Sigalla, L.A.

    1986-03-01

    Disposal of high-level nuclear waste in deep underground repositories may require the development of waste packages that will keep the radioisotopes contained for up to 1000 y. A number of iron-base materials are being considered for the structural barrier members of waste packages. Their uniform and nonuniform (pitting and intergranular) corrosion behavior and their resistance to stress-corrosion cracking in aqueous environments relevant to salt media are under study at Pacific Northwest Laboratory. The purpose of the work is to provide data for a materials degradation model that can ultimately be used to predict the effective lifetime of a waste package overpack in the actual repository environment. The corrosion behavior of the candidate materials was investigated in simulated intrusion brine (essentially NaCl) in flowing autoclave tests at 150/sup 0/C, and in combinations of intrusion/inclusion (high-Mg) brine environments in moist salt tests, also at 150/sup 0/C. Studies utilizing a /sup 60/Co irradiation facility were performed to determine the corrosion resistance of the candidate materials to products of brine radiolysis at dose rates of 2 x 10/sup 3/ and 1 x 10/sup 5/ rad/h and a temperature of 150/sup 0/C. These irradiation-corrosion tests were ''overtests,'' as the irradiation intensities employed were 10 to 1000 times as high as those expected at the surface of a thick-walled waste package. With the exception of the high general corrosion rates found in the tests using moist salt containing high-Mg brines, the ferrous materials exhibited a degree of corrosion resistance that indicates a potentially satisfactory application to waste package structural barrier members in a salt repository environment.

  14. EFFECT OF BACTERIAL SULFATE REDUCTION ON IRON-CORROSION SCALES

    EPA Science Inventory

    Iron-sulfur geochemistry is important in many natural and engineered environments including drinking water systems. In the anaerobic environment beneath scales of corroding iron drinking water distribution system pipes, sulfate reducing bacteria (SRB) produce sulfide from natura...

  15. EFFECT OF BACTERIAL SULFATE REDUCTION ON IRON-CORROSION SCALES

    EPA Science Inventory

    Iron-sulfur geochemistry is important in many natural and engineered environments including drinking water systems. In the anaerobic environment beneath scales of corroding iron drinking water distribution system pipes, sulfate reducing bacteria (SRB) produce sulfide from natura...

  16. Intravenous iron-containing products: EMA procrastination.

    PubMed

    2014-07-01

    A European reassessment has led to identical changes in the summaries of product characteristics (SPCs) for all intravenous iron-containing products: the risk of serious adverse effects is now highlighted, underlining the fact that intravenous iron-containing products should only be used when the benefits clearly outweigh the harms. Unfortunately, iron dextran still remains on the market despite a higher risk of hypersensitivity reactions than with iron sucrose.

  17. Erosion-corrosion for carbon steel in sweet production with sand: Modeling and experiments

    NASA Astrophysics Data System (ADS)

    Al-Mutahar, Faisal M.

    In the oil and gas production industry, carbon steel tubing and piping are susceptible to erosion-corrosion damage due to the erosive and corrosive nature of the flow. The combined effect of sand erosion and corrosion can be very significant. One form of erosion-corrosion of carbon steels occurs when impinging sand particles remove part or all of a protective iron carbonate (FeCO3) scale allowing corrosion rates to increase to bare metal rates. The role of a FeCO3 layer in reducing corrosion rates in sand-free environments has been studied by many investigators. However, the protection offered by FeCO3 scale when sand is produced is not well defined. A mechanistic approach for predicting metal loss due to sand erosion and CO2 corrosion of carbon steel was developed in the research presented in this thesis. The main contributions of the research were to develop: (1) a mechanistic model of the competition between FeCO 3 scale growth by precipitation and scale removal by erosion; (2) a procedure for predicting erosion-corrosion rates in oil and gas production and transportation systems; and, (3) a computer program to facilitate the prediction of the erosion-corrosion rates. Models from the literature for quantifying iron carbonate scale precipitation and growth rates, and diffusion rates of cathodic reactants and corrosion product species through iron carbonate scale were adapted to this purpose. The solid particle erosion resistance of FeCO3 scale produced under a range of environmental and flow conditions was characterized by direct impingement experiments. Dry and wet FeCO3 scales were subjected to direct impingement by sand at various impingement angles. Scales were pre-formed in a flow loop at 150-200°F (65-93°C), from 6.1-6.5 pH, and 2.4 bar CO2 pressure and then removed from the flow loop for direct impingement testing. The erosion pattern of the scale was characterized by scanning electron microscopy (SEM). Specimens with iron carbonate scale were partially

  18. Complementary Microorganisms in Highly Corrosive Biofilms from an Offshore Oil Production Facility.

    PubMed

    Vigneron, Adrien; Alsop, Eric B; Chambers, Brian; Lomans, Bartholomeus P; Head, Ian M; Tsesmetzis, Nicolas

    2016-04-01

    Offshore oil production facilities are frequently victims of internal piping corrosion, potentially leading to human and environmental risks and significant economic losses. Microbially influenced corrosion (MIC) is believed to be an important factor in this major problem for the petroleum industry. However, knowledge of the microbial communities and metabolic processes leading to corrosion is still limited. Therefore, the microbial communities from three anaerobic biofilms recovered from the inside of a steel pipe exhibiting high corrosion rates, iron oxide deposits, and substantial amounts of sulfur, which are characteristic of MIC, were analyzed in detail. Bacterial and archaeal community structures were investigated by automated ribosomal intergenic spacer analysis, multigenic (16S rRNA and functional genes) high-throughput Illumina MiSeq sequencing, and quantitative PCR analysis. The microbial community analysis indicated that bacteria, particularly Desulfovibrio species, dominated the biofilm microbial communities. However, other bacteria, such as Pelobacter, Pseudomonas, and Geotoga, as well as various methanogenic archaea, previously detected in oil facilities were also detected. The microbial taxa and functional genes identified suggested that the biofilm communities harbored the potential for a number of different but complementary metabolic processes and that MIC in oil facilities likely involves a range of microbial metabolisms such as sulfate, iron, and elemental sulfur reduction. Furthermore, extreme corrosion leading to leakage and exposure of the biofilms to the external environment modify the microbial community structure by promoting the growth of aerobic hydrocarbon-degrading organisms.

  19. Complementary Microorganisms in Highly Corrosive Biofilms from an Offshore Oil Production Facility

    PubMed Central

    Alsop, Eric B.; Chambers, Brian; Lomans, Bartholomeus P.; Head, Ian M.; Tsesmetzis, Nicolas

    2016-01-01

    Offshore oil production facilities are frequently victims of internal piping corrosion, potentially leading to human and environmental risks and significant economic losses. Microbially influenced corrosion (MIC) is believed to be an important factor in this major problem for the petroleum industry. However, knowledge of the microbial communities and metabolic processes leading to corrosion is still limited. Therefore, the microbial communities from three anaerobic biofilms recovered from the inside of a steel pipe exhibiting high corrosion rates, iron oxide deposits, and substantial amounts of sulfur, which are characteristic of MIC, were analyzed in detail. Bacterial and archaeal community structures were investigated by automated ribosomal intergenic spacer analysis, multigenic (16S rRNA and functional genes) high-throughput Illumina MiSeq sequencing, and quantitative PCR analysis. The microbial community analysis indicated that bacteria, particularly Desulfovibrio species, dominated the biofilm microbial communities. However, other bacteria, such as Pelobacter, Pseudomonas, and Geotoga, as well as various methanogenic archaea, previously detected in oil facilities were also detected. The microbial taxa and functional genes identified suggested that the biofilm communities harbored the potential for a number of different but complementary metabolic processes and that MIC in oil facilities likely involves a range of microbial metabolisms such as sulfate, iron, and elemental sulfur reduction. Furthermore, extreme corrosion leading to leakage and exposure of the biofilms to the external environment modify the microbial community structure by promoting the growth of aerobic hydrocarbon-degrading organisms. PMID:26896143

  20. Evaluation of steel corrosion products in tropical climates

    SciTech Connect

    Rincon, A.; Rincon, O.T. de; Haces, C.; Furet, N.R.; Corvo, F.

    1997-11-01

    Phase variations occurring in corrosion products obtained in steels exposed to different zones of tropical climate in Cuba and Venezuela were determined to establish their relationship to corrosion phenomena. Steel corrosion products were obtained at four test stations in both countries with marine, industrial, and rural characteristics. Phase composition was determined using x-ray diffraction (XRD), infrared (IR) spectroscopy, and Moessbauer spectroscopy. In the rural climate of both countries, the predominant phase was lepidocrocite ({gamma}-FeOOH), which was in agreement with reported corrosion rates. In the marine environments, corrosion products varied in composition. In Adicora, Venezuela, akaganeite ({beta}-FeOOH) was found, but in Cuba, this phase was nonexistent. Results were discussed in light of the contamination present and meteorological parameters recorded in the test zones.

  1. The Oxidation and Corrosion Resistance of Nitrided Iron Alloys.

    DTIC Science & Technology

    1981-07-27

    and mechanical properties of the nitrided alloys are understood. However, resistance of nitrided alloys to oxidation and corrosion has received...resulted in an order of magnitude decrease in current density compared with the un-nitrided alloy. The mechanism of corrosion was also found to change...suggested as suitable alternatives to AISI 304L and 316L (18Cr-8Ni types with molybdenum). The Armco Steel Corporation Nitronic series of austenitic

  2. Analysis of ZVI corrosion products and their functions in the combined ZVI and anaerobic sludge system.

    PubMed

    Zhu, Liang; Gao, Kaituo; Jin, Jie; Lin, Haizhuan; Xu, Xiangyang

    2014-11-01

    The zero-valent iron (ZVI) corrosion products and their functions were investigated in the combined ZVI and anaerobic sludge system. Results showed that ZVI corrosion occurred, and the reductive transformation and dechlorination of p-chloronitrobenzene (p-ClNB) by the anaerobic sludge were enhanced. In the combined systems with different types of ZVIs and mass ratios of anaerobic sludge to ZVI, a considerable amount of suspended iron compounds was produced and coated onto the microbial cells. However, the microbial cellular structure was damaged, and the p-ClNB reductive transformation was affected adversely after the long-term presence of nanoscale ZVI (NZVI) or reduced ZVI (RZVI) with a high concentration of 5 g L(-1). The oxidized products of FeOOH and Fe3O4 were found on the surface of ZVI, which are speculated to act as electron mediators and consequently facilitate the utilization of electron donors by the anaerobic microbes.

  3. THE EFFECT OF SMECTITE ON THE CORROSION OF IRON METAL

    SciTech Connect

    Balko, Barbara A.; Bosse, Stephanie A.; Cade, Anne E.; Jones-Landry, Elise F.; Amonette, James E.; Daschbach, John L.

    2012-04-24

    The combination of zero-valent iron and a clay-type amendment is often observed to have a synergistic effect on the rate of reduction reactions. In this paper, electrochemical techniques are used to determine the mechanism of interaction between the iron and smectite clay minerals. Iron electrodes coated with an evaporated smectite suspension (clay-modified iron electrodes, CMIEs) were prepared using five different smectites: SAz-1, SWa-1, STx-1, SWy-1, and SHCa-1. All the smectites were exchanged with Na+ and one sample of SWy-1 was also exchanged with Mg2+. Potentiodynamic potential scans and cyclic voltammograms were taken using the CMIEs and uncoated but passivated iron electrodes. These electrochemical experiments, along with measurements of the amount of Fe2+ and Fe3+ sorbed in the smectite coating, suggested that the smectite removed the passive layer of the underlying iron electrode during the evaporation process. Cyclic voltammograms taken after the CMIEs were biased at the active-passive transition potential for varying amounts of time suggested that the smectite limited growth of a passive layer, preventing passivation. These results are attributed to the Broensted acidity of the smectite as well as to its ability to sorb iron cations. Oxides that did form on the surface of the iron in the presence of the smectite when it was biased anodically seemed to be different than those that form on the surface of an uncoated iron electrode under otherwise similar conditions; this difference suggested that the smectite reacted with the Fe2+ formed from the oxidation of the underlying iron. No significant correlation could be found between the ability of the smectite to remove the iron passive film and the smectite type. The results have implications for the mixing of sediments and iron particles in permeable reactive barriers, underground storage of radioactive waste in steel canisters, and the use of smectite supports in preventing aggregation of nano-sized zero

  4. Strontium concentrations in corrosion products from residential drinking water distribution systems.

    PubMed

    Gerke, Tammie L; Little, Brenda J; Luxton, Todd P; Scheckel, Kirk G; Maynard, J Barry

    2013-05-21

    The United States Environmental Protection Agency (US EPA) will require some U.S. drinking water distribution systems (DWDS) to monitor nonradioactive strontium (Sr(2+)) in drinking water in 2013. Iron corrosion products from four DWDS were examined to assess the potential for Sr(2+) binding and release. Average Sr(2+) concentrations in the outermost layer of the corrosion products ranged from 3 to 54 mg kg(-1) and the Sr(2+) drinking water concentrations were all ≤0.3 mg L(-1). Micro-X-ray adsorption near edge structure spectroscopy and linear combination fitting determined that Sr(2+) was principally associated with CaCO3. Sr(2+) was also detected as a surface complex associated with α-FeOOH. Iron particulates deposited on a filter inside a home had an average Sr(2+) concentration of 40.3 mg kg(-1) and the associated drinking water at a tap was 210 μg L(-1). The data suggest that elevated Sr(2+) concentrations may be associated with iron corrosion products that, if disturbed, could increase Sr(2+) concentrations above the 0.3 μg L(-1) US EPA reporting threshold. Disassociation of very small particulates could result in drinking water Sr(2+) concentrations that exceed the US EPA health reference limit (4.20 mg kg(-1) body weight).

  5. Microelectrodes Based investigation of the Impacts of Water Chemistry on Copper and Iron Corrosion

    EPA Science Inventory

    The effect of bulk drinking water quality on copper and iron pipe corrosion has been extensively studied. Despite past research, many have argued that bulk water quality does not necessarily reflect water quality near the water-metal interface and that such knowledge is necessary...

  6. Microelectrodes Based investigation of the Impacts of Water Chemistry on Copper and Iron Corrosion

    EPA Science Inventory

    The effect of bulk drinking water quality on copper and iron pipe corrosion has been extensively studied. Despite past research, many have argued that bulk water quality does not necessarily reflect water quality near the water-metal interface and that such knowledge is necessary...

  7. Corrosion

    ERIC Educational Resources Information Center

    Slabaugh, W. H.

    1974-01-01

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

  8. Corrosion

    ERIC Educational Resources Information Center

    Slabaugh, W. H.

    1974-01-01

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

  9. Study of corrosion using long period fiber gratings coated with iron exposed to salty water

    NASA Astrophysics Data System (ADS)

    Coelho, L.; Santos, J. L.; Jorge, P. A. S.; de Almeida, J. M. M.

    2017-04-01

    A study of long period fiber gratings (LPFG) over coated with iron (Fe) and subjected to oxidation in water with different sodium chloride (NaCl) concentrations is presented. The formation of iron oxides and hydroxides was monitored in real time by following the features of the LPFG attenuation band. Preliminary results show that Fe coated LPFGs can be used as sensors for early warning of corrosion in offshore and in coastal projects where metal structures made of iron alloys are in contact with sea or brackish water.

  10. Corrosion behavior of Inconel 690 and 693 in an iron phosphate melt

    NASA Astrophysics Data System (ADS)

    Zhu, Dongmei; Kim, Cheol-Woon; Day, Delbert E.

    2005-01-01

    The corrosion resistance of Inconel 690 and 693 coupons submerged in an iron phosphate melt has been investigated. After 155 days in an iron phosphate melt at 1050 °C, which contained 30 wt% of a simulated low activity waste (LAW at Hanford), the weight loss of Inconel 690 and 693 was 14% and 8%, respectively. The overall corrosion rate, calculated from the initial and final dimensions of each coupon, was 1.3 and 0.7 μm/day for the Inconel 690 and 693, respectively. Scanning electron microscopy and X-ray diffraction of the submerged Inconel coupons after 155 days in the iron phosphate melt showed that an altered surface layer had formed which was depleted in nickel and consisted of a (Fe, Cr) 2O 3 solid solution. This altered layer appears to be chemically protective as indicated by the gradual reduction in weight loss which occurred with time in the iron phosphate melt. Inconel 693 appears to be a better candidate to use as an electrode in iron phosphate melts since its corrosion rate and weight loss was only about one half that of Inconel 690.

  11. Progress in combating microbiologically induced corrosion in oil production

    SciTech Connect

    Ciaraldi, S.W.; Ghazal, H.H.; Abou Shadey, T.H.; El-Leil, H.A.; El-Raghy, S.M.

    1999-11-01

    Widespread microbial activity has caused substantial recent corrosion problems throughout a major mature oil production operation. Control over this situation is gradually being gained through advances in several areas, These include improved understanding of the reservoir souring process, operational factors contributing to biocell formation/propagation, the role of bio-breeders in promoting corrosion and the kinetics of attack. Synergistic beneficial effects of cleaning programs (pigging, chemical treatments, etc.) and biocide/corrosion inhibitor injections have now been well demonstrated, with corrosion rates reduced to nil in many places, even in significantly damaged systems. Feasibility studies of new de-souring technologies have been performed with encouraging results and these offer the potential for successful and cost-effective long-term control of microbiologically induced corrosion (MIC) in several possible operational areas.

  12. Correlation Of 2-Chlorobiphenyl Dechlorination By Fe/Pd With Iron Corrosion At Different pH

    EPA Science Inventory

    The rate of 2-chlorobiphenyl dechlorination by palladized iron (Fe/Pd) decreased with increasing pH until pH > 12.5. Iron corrosion potential (Ec) and current (jc), obtained from polarization curves of a rotating disk electrode of iron, followed the Tafel e...

  13. Correlation Of 2-Chlorobiphenyl Dechlorination By Fe/Pd With Iron Corrosion At Different pH

    EPA Science Inventory

    The rate of 2-chlorobiphenyl dechlorination by palladized iron (Fe/Pd) decreased with increasing pH until pH > 12.5. Iron corrosion potential (Ec) and current (jc), obtained from polarization curves of a rotating disk electrode of iron, followed the Tafel e...

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

    PubMed

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

    2013-06-05

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

  15. High-Performance Corrosion-Resistant Iron-Based Amorphous Metals: The Effects of Composition, Structure and Environment on Corrosion Resistance

    SciTech Connect

    Farmer, J; Choi, J S; Haslam, J; Lian, T; Day, S; Yang, N; Blue, C; Peters, W; Bayles, R; Lewandowski, J; Perepezko, J; Hildal, K; Lavernia, E; Ajdelsztajn, A; Grave, O; Aprigliano, L; Kaufman, L; Boudreau, J; Branagan, D J; Beardsley, B

    2006-04-11

    New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative thermal phase stability, microstructure, mechanical properties, damage tolerance, and corrosion resistance. Some alloy additions are known to promote glass formation and to lower the critical cooling rate [F. Guo, S. J. Poon, Applied Physics Letters, 83 (13) 2575-2577, 2003]. Other elements are known to enhance the corrosion resistance of conventional stainless steels and nickel-based alloys [A. I. Asphahani, Materials Performance, Vol. 19, No. 12, pp. 33-43, 1980] and have been found to provide similar benefits to iron-based amorphous metals. Many of these materials can be cast as relatively thick ingots, or applied as coatings with advanced thermal spray technology. A wide variety of thermal spray processes have been developed by industry, and can be used to apply these new materials as coatings. Any of these can be used for the deposition of the formulations discussed here, with varying degrees of residual porosity and crystalline structure. Thick protective coatings have now been made that are fully dense and completely amorphous in the as-sprayed condition. An overview of the High-Performance Corrosion Resistant Materials (HPCRM) Project will be given, with particular emphasis on the corrosion resistance of several different types of iron-based amorphous metals in various environments of interest. The salt fog test has been used to compare the performance of various wrought alloys, melt-spun ribbons, arc-melted drop-cast ingots, and thermal-spray coatings for their susceptibility to corrosion in marine environments. Electrochemical tests have also been performed in seawater. Spontaneous breakdown of the passive film and localized corrosion require that the open-circuit corrosion potential exceed the critical potential. The resistance to localized corrosion is seawater has been

  16. Characterization of biofilm and corrosion of cast iron pipes in drinking water distribution system with UV/Cl2 disinfection.

    PubMed

    Zhu, Ying; Wang, Haibo; Li, Xiaoxiao; Hu, Chun; Yang, Min; Qu, Jiuhui

    2014-09-01

    The effect of UV/Cl2 disinfection on the biofilm and corrosion of cast iron pipes in drinking water distribution system were studied using annular reactors (ARs). Passivation occurred more rapidly in the AR with UV/Cl2 than in the one with Cl2 alone, decreasing iron release for higher corrosivity of water. Based on functional gene, pyrosequencing assays and principal component analysis, UV disinfection not only reduced the required initial chlorine dose, but also enhanced denitrifying functional bacteria advantage in the biofilm of corrosion scales. The nitrate-reducing bacteria (NRB) Dechloromonas exhibited the greatest corrosion inhibition by inducing the redox cycling of iron to enhance the precipitation of iron oxides and formation of Fe3O4 in the AR with UV/Cl2, while the rhizobia Bradyrhizobium and Rhizobium, and the NRB Sphingomonas, Brucella producing siderophores had weaker corrosion-inhibition effect by capturing iron in the AR with Cl2. These results indicated that the microbial redox cycling of iron was possibly responsible for higher corrosion inhibition and lower effect of water Larson-Skold Index (LI) changes on corrosion. This finding could be applied toward the control of water quality in drinking water distribution systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. A quantitative method to evaluate corrosion products in tissues.

    PubMed

    Cabrini, R L; Olmedo, D G; Guglielmotti, M B

    2003-01-01

    The use of odontological or orthopedic metal implants requires the availability of techniques to estimate tissue response to the corrosion processes. In previous experimental studies we showed the deposition of corrosion products not only locally (Olmedo et al., Implant Dent 2003; 12: 75-80) but also systemically (Olmedo et al., J Mater Sci: Mater in Medic 2002; 13: 793-796) in organs such as liver, spleen and lung. The aim of the present study was to propose a method to quantitatively assess the tissue deposits of the corrosion products of the materials used to manufacture implants. The samples (liver and lung) were embedded in paraffin, and the histological sections were submitted to thickness standardization. The quantitative evaluation of the deposits was performed in an MPM-800 (Carl Zeiss)* microscope. The light microscopy images were digitalized and then analyzed employing the DNA-IBAS-Kontron software that allows for the identification and evaluation of cells loaded with corrosion products (objective 20x). The following end-points were assessed: total field area, number of deposits of corrosion products, partial and total area of the deposits, and the ratio between volume of the deposits and tissue volume. The method proposed serves to quantitatively evaluate, at light microscopy level, the deposition of corrosion products in tissues.

  18. Neutrophilic iron-oxidizing "zetaproteobacteria" and mild steel corrosion in nearshore marine environments.

    PubMed

    McBeth, Joyce M; Little, Brenda J; Ray, Richard I; Farrar, Katherine M; Emerson, David

    2011-02-01

    Microbiologically influenced corrosion (MIC) of mild steel in seawater is an expensive and enduring problem. Little attention has been paid to the role of neutrophilic, lithotrophic, iron-oxidizing bacteria (FeOB) in MIC. The goal of this study was to determine if marine FeOB related to Mariprofundus are involved in this process. To examine this, field incubations and laboratory microcosm experiments were conducted. Mild steel samples incubated in nearshore environments were colonized by marine FeOB, as evidenced by the presence of helical iron-encrusted stalks diagnostic of the FeOB Mariprofundus ferrooxydans, a member of the candidate class "Zetaproteobacteria." Furthermore, Mariprofundus-like cells were enriched from MIC biofilms. The presence of Zetaproteobacteria was confirmed using a Zetaproteobacteria-specific small-subunit (SSU) rRNA gene primer set to amplify sequences related to M. ferrooxydans from both enrichments and in situ samples of MIC biofilms. Temporal in situ incubation studies showed a qualitative increase in stalk distribution on mild steel, suggesting progressive colonization by stalk-forming FeOB. We also isolated a novel FeOB, designated Mariprofundus sp. strain GSB2, from an iron oxide mat in a salt marsh. Strain GSB2 enhanced uniform corrosion from mild steel in laboratory microcosm experiments conducted over 4 days. Iron concentrations (including precipitates) in the medium were used as a measure of corrosion. The corrosion in biotic samples (7.4 ± 0.1 mM) was significantly higher than that in abiotic controls (5.0 ± 0.1 mM). These results have important implications for the role of FeOB in corrosion of steel in nearshore and estuarine environments. In addition, this work shows that the global distribution of Zetaproteobacteria is far greater than previously thought.

  19. Interactions of corrosion products and bentonite: An extended multicomponent reactive transport model

    NASA Astrophysics Data System (ADS)

    Lu, Chuanhe; Samper, Javier; Fritz, Bertrand; Clement, Alain; Montenegro, Luis

    Radioactive waste disposal in deep geological repositories envisages various engineered barriers such as carbon-steel canisters and compacted bentonite. Canister corrosion and the chemical interactions of corrosion products with bentonite are key reactions for the long term performance of a repository. Samper, Lu, and Montenegro (Physics and Chemistry of the Earth 2008; 33S: S306-S316) reported numerical models to simulate canister corrosion and the interactions of corrosion products with bentonite for the near field of a repository in granite. Here we present an updated version of their reactive transport model which accounts for: (1) Three types of sorption sites in the bentonite; (2) Kinetically-controlled canister corrosion, (3) Kinetically-controlled magnetite precipitation; and (4) The competition effect of Ni 2+ for sorbing sites. Accounting for kinetically-controlled canister corrosion leads to a significant reduction in the corrosion rate. Uncertainties in the surface complexation reactions play a minor role in the time evolution of the computed pH in the bentonite and the granite. Computed iron concentrations, however, are very sensitive to changes in the surface complexation reactions. The apparent distribution coefficient of Fe computed with the three-site model is 10 times larger than that obtained with a single-site model. The concentration of dissolved Fe computed with kinetic magnetite precipitation is smaller than that obtained with magnetite precipitation at local equilibrium. The largest difference in the concentration of dissolved Fe occurs after 3 × 10 4 years. The competition of Ni 2+ for sorption sites affects significantly the chemical evolution of the bentonite porewater. The sorption of Ni 2+ on bentonite releases protons and therefore the pH in the bentonite is smaller than that computed without Ni 2+ transport. The sorption of Ni 2+ leads to a decrease of the concentration of sorbed Fe and an increase of the concentration of dissolved

  20. Long-Term Corrosion Processes of Iron and Steel Shipwrecks in the Marine Environment: A Review of Current Knowledge

    NASA Astrophysics Data System (ADS)

    Moore, James D.

    2015-12-01

    Methodologies for examining the corrosion behavior of iron and steel shipwrecks have steadily progressed since the 1970s, but the analytical techniques utilized since then are comparatively site-specific, and the overall quantity of data available for independent review is seemingly limited. Laudable advancements in the fields of maritime archaeology, oceanography, and corrosion science support the determination that microbiologically-influenced corrosion primarily controls the degradation rates of iron and steel shipwrecks over archaeological timescales. Future in situ analyses performed on these shipwreck sites need to consider the overreaching impacts that microbiological metabolism have on long-term corrosion rates. The corrosion behavior of an iron or steel archaeological shipwreck site should also not be readily applied to similar sites or to other wrecked vessels that are in close proximity.

  1. Corrosion Testing of Carbon Steel in Oxalic Acid that Contains Dissolved Iron

    SciTech Connect

    Wiersma, Bruce J.; Mickalonis, John I.; Subramanian, Karthik H.

    2012-10-11

    Radioactive liquid waste has been stored in underground carbon steel tanks for nearly 60 years at the Savannah River Site. The site is currently in the process of removing the waste from these tanks in order to place it into vitrified, stable state for longer term storage. The last stage in the removal sequence is a chemical cleaning step that breaks up and dissolves metal oxide solids that cannot be easily pumped out of the tank. Oxalic acid (OA) will be used to chemically clean the tanks after waste retrieval is completed. The waste tanks at SRS were constructed from carbon steel materials and thus are vulnerable to corrosion in acidic media. In addition to structural impacts, the impact of corrosion on the hydrogen generated during the process must be assessed. Electrochemical and coupon immersion tests were used to investigate the corrosion mechanism at anticipated process conditions. The testing showed that the corrosion rates were dependent upon the reduction of the iron species that had dissolved in solution. Initial corrosion rates were elevated due to the reduction of the ferric species to ferrous species. At later times, as the ferric species depleted, the corrosion rate decreased. On the other hand, the hydrogen evolution reaction became more dominant.

  2. Effects of sulfate on heavy metal release from iron corrosion scales in drinking water distribution system.

    PubMed

    Sun, Huifang; Shi, Baoyou; Yang, Fan; Wang, Dongsheng

    2017-05-01

    Trace heavy metals accumulated in iron corrosion scales within a drinking water distribution system (DWDS) could potentially be released to bulk water and consequently deteriorate the tap water quality. The objective of this study was to identify and evaluate the release of trace heavy metals in DWDS under changing source water conditions. Experimental pipe loops with different iron corrosion scales were set up to simulate the actual DWDS. The effects of sulfate levels on heavy metal release were systemically investigated. Heavy metal releases of Mn, Ni, Cu, Pb, Cr and As could be rapidly triggered by sulfate addition but the releases slowly decreased over time. Heavy metal release was more severe in pipes transporting groundwater (GW) than in pipes transporting surface water (SW). There were strong positive correlations (R(2) > 0.8) between the releases of Fe and Mn, Fe and Ni, Fe and Cu, and Fe and Pb. When switching to higher sulfate water, iron corrosion scales in all pipe loops tended to be more stable (especially in pipes transporting GW), with a larger proportion of stable constituents (mainly Fe3O4) and fewer unstable compounds (β-FeOOH, γ-FeOOH, FeCO3 and amorphous iron oxides). The main functional iron reducing bacteria (IRB) communities were favorable for the formation of Fe3O4. The transformation of corrosion scales and the growth of sulfate reducing bacteria (SRB) accounted for the gradually reduced heavy metal release with time. The higher metal release in pipes transporting GW could be due to increased Fe6(OH)12CO3 content under higher sulfate concentrations.

  3. Iron-Based Amorphous-Metals: High-Performance Corrosion-Resistant Materials (HPCRM) Development Final Report

    SciTech Connect

    Farmer, J C; Choi, J; Saw, C; Haslem, J; Day, D; Hailey, P; Lian, T; Rebak, R; Perepezko, J; Payer, J; Branagan, D; Beardsley, B; D'Amato, A; Aprigliano, L

    2009-03-16

    An overview of the High-Performance Corrosion-Resistant Materials (HPCRM) Program, which was co-sponsored by the Defense Advanced Research Projects Agency (DARPA) Defense Sciences Office (DSO) and the United States Department of Energy (DOE) Office of Civilian and Radioactive Waste Management (OCRWM), is discussed. Programmatic investigations have included a broad range of topics: alloy design and composition; materials synthesis; thermal stability; corrosion resistance; environmental cracking; mechanical properties; damage tolerance; radiation effects; and important potential applications. Amorphous alloys identified as SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) and SAM1651 (Fe{sub 48}Mo{sub 14}Cr{sub 15}Y{sub 2}C{sub 15}B{sub 6}) have been produced as melt-spun ribbons, drop-cast ingots and thermal-spray coatings. Chromium (Cr), molybdenum (Mo) and tungsten (W) additions provided corrosion resistance, while boron (B) enabled glass formation. Earlier electrochemical studies of melt-spun ribbons and ingots of these amorphous alloys demonstrated outstanding passive film stability. More recently thermal-spray coatings of these amorphous alloys have been made and subjected to long-term salt-fog and immersion tests. Good corrosion resistance has been observed during salt-fog testing. Corrosion rates were measured in situ with linear polarization, while simultaneously monitoring the open-circuit corrosion potentials. Reasonably good performance was observed. The sensitivity of these measurements to electrolyte composition and temperature was determined. The high boron content of this particular amorphous metal make this amorphous alloy an effective neutron absorber, and suitable for criticality control applications. In general, the corrosion resistance of these iron-based amorphous metals is maintained at operating temperatures up to the glass transition temperature. These materials are much harder than conventional

  4. Fracture of concrete caused by the reinforcement corrosion products

    NASA Astrophysics Data System (ADS)

    Nguyen, Q. T.; Millard, A.; Caré, S.; L'Hostis, V.; Berthaud, Y.

    2006-11-01

    One of the most current degradations in reinforced concrete structures is related to the corrosion of the reinforcements. The corrosion products during active corrosion induce a mechanical pressure on the surrounding concrete that leads to cover cracking along the rebar. The objective of this work is to study the cracking of concrete due to the corrosion of the reinforcements. The phenomenon of corrosion/cracking is studied in experiments through tests of accelerated corrosion on plate and cylindrical specimens. A CCD camera is used to take images every hour and the pictures are analyzed by using the intercorrelation image technique (Correli^LMT) to derive the displacement and strain field. Thus the date of appearance of the first through crack is detected and the cinematic crack initiations are observed during the test. A finite element model that allows prediction of the mechanical consequences of the corrosion of steel in reinforced concrete structures is proposed. From the comparison between the test results and numerical simulations, it may be concluded that the model is validated in term of strains up to the moment when the crack becomes visible, and in terms of crack pattern.

  5. Analyses of fuel crud and coolant-borne corrosion products in normal water chemistry BWRs

    NASA Astrophysics Data System (ADS)

    Sawicki, Jerzy A.

    2011-12-01

    The samples of crud removed from the surface of fuel rods and corrosion products sampled by filtration of condensate and feed water in three boiling water reactors (BWR) operating at normal water chemistry (NWC) were analyzed using 57Fe Mössbauer spectroscopy. The corrosion products concentration and phase composition was examined in filter membranes exposed to influent and effluent of condensate polishing resin beds, as well as to final feed water. The brushed and scraped portions of fuel crud extracted from fuel rods during refueling outage comprised mostly hematite, α-Fe 2O 3, and submicron-sized goethite particles, α-FeOOH, in weight ratio similar to that observed in feed water. The observed phases are consistent with the oxidizing water chemistry of NWC BWRs. The feasibility of identifying other iron oxides and oxyhydroxides, as well as copper and zinc bearing phases in corrosion products from BWRs is briefly discussed. The results of this work can be used to better understand and minimize iron transport and crud deposition on fuel rods in BWRs.

  6. Evaluation of Iron Aluminide Weld Overlays for Erosion-Corrosion Resistant Boiler Tube Coatings in Low NOx Boilers

    SciTech Connect

    Regina, J.R.; Lim, M.; Barbosa, N., DuPont, J.N.; Marder, A.R.

    2000-04-28

    Iron aluminide weld overlays containing ternary additions and thermal spray coatings are being investigated for corrosion protection of boiler tubes in Low NO{sub x} burners. The primary objective of the research is to identify overlay and thermal spray compositions that provide corrosion protection of waterwall boiler tubes.

  7. Development of weldable, corrosion-resistant iron-aluminide alloys

    SciTech Connect

    Maziasz, P.J.; Goodwin, G.M.; Wang, X.L.

    1995-05-01

    Corrosion-resistant, weldable FeAl alloys have been developed with improved high-temperature strength industrial applications. Previous processing difficulties with these alloys led to their evaluation as weld-overlay claddings on conventional structural steels to take advantage of their good properties now. Simplified and better processing methods for monolithic FeAl components are also currently being developed so that components for industrial testing can be made. Other avenues for producing FeAl coatings are currently being explored. Neutron scattering experiments residual stress distributions in the FeAl weld-overlay cladding began in FY 1993 and continued this year.

  8. Corrosion behaviors and effects of corrosion products of plasma electrolytic oxidation coated AZ31 magnesium alloy under the salt spray corrosion test

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Huang, Zhiquan; Yan, Qin; Liu, Chen; Liu, Peng; Zhang, Yi; Guo, Changhong; Jiang, Guirong; Shen, Dejiu

    2016-08-01

    The effects of corrosion products on corrosion behaviors of AZ31 magnesium alloy with a plasma electrolytic oxidation (PEO) coating were investigated under the salt spray corrosion test (SSCT). The surface morphology, cross-sectional microstructure, chemical and phase compositions of the PEO coating were determined using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction analysis (XRD), respectively. Further, the corrosion process of the samples under the SSCT was examined in a non-aqueous electrolyte (methanol) using electrochemical impedance spectroscopy (EIS) coupled with equivalent circuit. The results show that the inner layer of the coating was destroyed firstly and the corrosion products have significant effects on the corrosion behaviors of the coating. The results above are discussed and an electrochemical corrosion model is proposed in the paper.

  9. Superhydrophobic surface fabricated on iron substrate by black chromium electrodeposition and its corrosion resistance property

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Feng, Haitao; Lin, Feng; Wang, Yabin; Wang, Liping; Dong, Yaping; Li, Wu

    2016-08-01

    The fabrication of superhydrophobic surface on iron substrate is carried out through 20 min black chromium electrodeposition, followed by immersing in 0.05 M ethanolic stearic acid solution for 12 h. The resultant superhydrophobic complex film is characterized by scanning electron microscope (SEM), disperse Spectrometer (EDS), atomic force microscope (AFM), water contact angle (CA), sliding angle (SA) and X-ray photoelectron spectroscope (XPS), and its corrosion resistance property is measured with cyclic voltammetry (CV), linear polarization and electrochemical impedance spectroscopy (EIS). The results show that the fabricated superhydrophobic film has excellent water repellency (CA, 158.8°; SA, 2.1°) and significantly high corrosion resistance (1.31 × 106 Ω cm-2) and excellent corrosion protection efficiency (99.94%).

  10. COUPLED IRON CORROSION AND CHROMATE REDUCTION: MECHANISMS FOR SUBSURFACE REMEDIATION

    EPA Science Inventory

    The reduction of chromium from the Cr(VI) to the Cr- (Ill) state by the presence of elemental, or zero-oxidation-state, iron metal was studied to evaluate the feasibility of such a process for subsurface chromate remediation. Reactions were studied in systems of natural aquifer m...

  11. COUPLED IRON CORROSION AND CHROMATE REDUCTION: MECHANISMS FOR SUBSURFACE REMEDIATION

    EPA Science Inventory

    The reduction of chromium from the Cr(VI) to the Cr- (Ill) state by the presence of elemental, or zero-oxidation-state, iron metal was studied to evaluate the feasibility of such a process for subsurface chromate remediation. Reactions were studied in systems of natural aquifer m...

  12. Effects of surface condition on aqueous corrosion and environmental embrittlement of iron aluminides

    SciTech Connect

    Perrin, R.L.; Buchanan, R.A.

    1996-08-01

    Effects of retained high-temperature surface oxides, produced during thermomechanical processing and/or heat treatment, on the aqueous-corrosion and environmental-embrittlement characteristics of Fe{sub 3}Al-based iron aluminides (FA-84, FA-129 and FAL-Mo), a FeAl-based iron aluminide (FA-385), and a disordered low-aluminum Fe-Al alloy (FAPY) were evaluated. All tests were conducted at room temperature in a mild acid-chloride solution. In cyclic-anodic-polarization testing for aqueous-corrosion behavior, the surface conditions examined were: as-received (i.e., with the retained high-temperature oxides), mechanically cleaned and chemically cleaned. For all materials, the polarization tests showed the critical pitting potentials to be significantly lower in the as-received condition than in the mechanically-cleaned and chemically-cleaned conditions. These results indicate detrimental effects of the retained high-temperature oxides in terms of increased susceptibilities to localized corrosion. In 200-hour U-bend stress-corrosion-cracking tests for environmental-embrittlement behavior, conducted at open-circuit corrosion potentials and at a hydrogen-charging potential of {minus}1500 mV (SHE), the above materials (except FA-385) were examined with retained oxides and with mechanically cleaned surfaces. At the open-circuit corrosion potentials, none of the materials in either surface condition underwent cracking. At the hydrogen-charging potential, none of the materials with retained oxides underwent cracking, but FA-84, FA-129 and FAL-Mo in the mechanically cleaned condition did undergo cracking. These results suggest beneficial effects of the retained high-temperature oxides in terms of increased resistance to environmental hydrogen embrittlement.

  13. Some nonionic surfactants as inhibitors of the corrosion of iron in acid chloride solutions

    SciTech Connect

    Elachouri, M.; Hajji, M.S.; Salem, M.; Kertit, S.; Aride, J.; Coudert, R.; Essassi, E.

    1996-02-01

    The inhibition effect of the surfactants 1,2-hexanediol (HD), 1,2,3-octanetriol (OT); 1,2,3-nonanetriol (NT); and 3,7-dimethyl-1,2,3,6,7-octanepentol (DOP) on the corrosion of iron in 1 M hydrochloric acid (HCl) was studied. Results obtained from gravimetric methods showed inhibition efficiencies increased with increasing surfactant concentrations and attained a maximum round their critical micellar concentration (cmc). A comparative study of corrosion inhibition of surfactants indicted DOP was the best inhibitor. Polarization measurements showed DOP was a cathodic type-inhibitor and acted on the cathodic reaction without modifying the mechanism of the hydrogen evolution reaction. DOP appeared to function through a general adsorption mode following the Langmuir adsorption isotherm. The effect of temperature on the corrosion behavior of iron in both 1 M HCl and 1 M HCl with addition of various concentrations of DOP was studied in the temperature range from 18 C to 48 C. The associated activation corrosion and free adsorption energies were determined.

  14. Effect of bacterial communities on the formation of cast iron corrosion tubercles in reclaimed water.

    PubMed

    Jin, Juntao; Wu, Guangxue; Guan, Yuntao

    2015-03-15

    To understand the role bacterial communities play in corrosion scale development, the morphological and physicochemical characteristics of corrosion scales in raw and disinfected reclaimed water were systematically investigated. Corrosion tubercles were found in raw reclaimed water while thin corrosion layers formed in disinfected reclaimed water. The corrosion tubercles, composed mainly of α-FeOOH, γ-FeOOH, and CaCO3, consisted of an top surface; a shell containing more magnetite than other layers; a core in association with stalks produced by bacteria; and a corroded layer. The thin corrosion layers also had layered structures. These had a smooth top, a dense middle, and a corroded layer. They mostly consisted of the same main components as the tubercles in raw reclaimed water, but with different proportions. The profiles of the dissolved oxygen (DO) concentration, redox potential, and pH in the tubercles were different to those in the corrosion layers, which demonstrated that these parameters changed with a shift in the microbial processes in the tubercles. The bacterial communities in the tubercles were found to be dominated by Proteobacteria (56.7%), Bacteroidetes (10.0%), and Nitrospira (6.9%). The abundance of sequences affiliated to iron-reducing bacteria (IRB, mainly Geothrix) and iron-oxidizing bacteria (mainly Aquabacterium) was relatively high. The layered characteristics of the corrosion layers was due to the blocking of DO transfer by the development of the scales themselves. Bacterial communities could at least promote the layering process and formation of corrosion tubercles. Possible mechanisms might include: (1) bacterial communities mediated the pH and redox potential in the tubercles (which helped to form shell-like and core layers), (2) the metabolism of IRB and magnetic bacteria (Magnetospirillum) might contribute to the presence of Fe3O4 in the shell-like layer, while IRB contributed to green rust in the core layer, and (3) the diversity of

  15. Microstructure Aspects of a Newly Developed, Low Cost, Corrosion-Resistant White Cast Iron

    NASA Astrophysics Data System (ADS)

    Sain, P. K.; Sharma, C. P.; Bhargava, A. K.

    2013-04-01

    The purpose of this work is to study the influence of heat treatment on the corrosion resistance of a newly developed white cast iron, basically suitable for corrosion- and wear-resistant applications, and to attain a microstructure that is most suitable from the corrosion resistance point of view. The composition was selected with an aim to have austenitic matrix both in as-cast and heat-treated conditions. The difference in electrochemical potential between austenite and carbide is less in comparison to that between austenite and graphite. Additionally, graphitic corrosion which is frequently encountered in gray cast irons is absent in white cast irons. These basic facts encouraged us to undertake this work. Optical metallography, hardness testing, X-ray diffractometry, and SEM-EDX techniques were employed to identify the phases present in the as-cast and heat-treated specimens of the investigated alloy and to correlate microstructure with corrosion resistance and hardness. Corrosion testing was carried out in 5 pct NaCl solution (approximate chloride content of sea water) using the weight loss method. In the investigated alloy, austenite was retained the in as-cast and heat-treated conditions. The same was confirmed by X-ray and EDX analysis. The stability and volume fraction of austenite increased with an increase of heat-treated temperature/time with a simultaneous decrease in the volume fraction of massive carbides. The decrease in volume fraction of massive carbides resulted in the availability of alloying elements. These alloying elements, on increasing the heat treatment temperature or increasing the soaking period at certain temperatures, get dissolved in austenite. As a consequence, austenite gets enriched as well as becomes more stable. On cooling from lower soaking period/temperature, enriched austenite decomposes to lesser enriched austenite and to a dispersed phase due to decreasing solid solubility of alloying elements with decreasing temperature

  16. Effect of coating time on corrosion behavior of electroless nickel-phosphorus coated powder metallurgy iron specimens

    SciTech Connect

    Singh, D.; Balasubramaniam, R.; Dube, R.K.

    1995-08-01

    Powder metallurgy iron specimens with porosities in the range 0% to 2% were electroless coated with nickel-phosphorus alloy from baths containing sodium hypophosphite (NaH{sub 2}PO{sub 2}{center_dot}H{sub 2}O). The effect of coating time on thickness and phosphorus content of the deposit was analyzed. The free corrosion potentials and corrosion rates of the coated specimens were obtained by the Tafel extrapolation method in 1.0 M hydrochloric acid (HCl) solution. Corrosion rates of the coated specimens after heat treatment also were studied. The observed corrosion characteristics were explained by the mixed-potential theory.

  17. Magnetostriction and corrosion studies in single crystals of iron-gallium alloys

    NASA Astrophysics Data System (ADS)

    Jayaraman, Tanjore V.

    Iron-gallium alloys have an excellent combination of large low-field magnetostriction, good mechanical properties, low hysteresis, and relatively low cost. This dissertation focuses on the magneto striction and corrosion behaviors of single crystals of Fe-Ga alloys. In the first part, the variation of magnetostrictive coefficient: (3/2) lambda100, with composition and heat treatment conditions of Fe-Ga alloys, is examined. Single crystals with compositions Fe-15 at.% Ga, Fe-20 at.% Ga, and Fe-27.5 at.% Ga were obtained by (a) vertical Bridgman technique (DG) and (b) vertical Bridgman technique followed by long-term annealing (LTA) and quenching. Rapid quenching from a phase region improves the (3/2) lambda 100 value in these alloys. X-ray diffraction characterization showed for the first time the direct evidence of short-range ordering in these alloys. The second part reports the first study of alpha" ordering heat treatment on the elastic properties and magnetostriction of Fe-27.5 at.% Ga alloy single crystals. The elastic constants were measured using resonant ultrasound spectroscopy (RUS), and the elastic properties and magneto-elastic coupling constant were calculated. The (3/2) lambda100 and B1 values obtained for a phase were higher than alpha" phase. The third part examines the first study of corrosion behavior of as-cast FeGa and Fe-Ga-Al alloys in acidic, basic, and simulated seawater environments. Corrosion measurements were performed by Tafel scan and polarization resistance method and in general exhibited good corrosion resistance. The fourth part examines the first study of corrosion behavior of Fe-15 at.% Ga, Fe-20 at.% Ga, and Fe-27.5 at.% Ga DG and LTA alloy single crystals and the dependence of corrosion rates on the crystal orientations. The corrosion resistance was better in basic environments followed by simulated seawater and acidic environments. The fifth part examines the effect of magnetostriction on the corrosion behavior of [100]-oriented

  18. Effect of temperature on the corrosion inhibition of iron in liquid lead using oxygen inhibitor: studied by MD simulation

    NASA Astrophysics Data System (ADS)

    Arkundato, Artoto; Monado, Fiber; Su'ud, Zaki

    2017-05-01

    For corrosion mitigation of steels used in a fast nuclear reactor power plant, oxygen gas is one of promising candidates of inhibitors. Many experiments have been conducted to reveal the mechanism of corrosion and mechanism of how to overcome the corrosion. In the previous work, we had shown computationally that the oxygen atom can be used to reduce the corrosion and we had predicted the oxygen contents. In the current work, not only to explore deeeper the ability of oxygen gas to reduce the corrosion, but also to include the variation of used temperature. We still used iron material to represent a real steels. Using MD (molecular dynamics) simulation based on the Lennard-Jones interaction potential, we sought to understand the concentration of oxygen gas as variation of temperature used in the reactor for the best corrosion mitigation. From this work, we conclude that the temperature does not give effect in related with how concentration of injected oxygen. The temparature merely affects to rise the diffusion coefficient of iron in liquid lead, yet it does not influence how much oxygen needed for corrosion mitigation. In this work, all simulations on different series of temperatures (1023°K, 1073°K, 1123°K, 1173°K) reveals that oxygen content of 0.1151wt% will cause the lowest corrosion level of iron in liquid lead.

  19. ROLE OF IRON (II, III) HYDROXYCARBONATE GREEN RUST IN ARSENIC REMEDIATION USING ZEROVALENT IRON IN COLUMN TESTS

    EPA Science Inventory

    We examined corrosion products of zerovalent iron (Peerless iron) that was used in three column tests for removing arsenic under dynamic flow conditions with and without added phosphate and silicate. Iron(II, III) hydroxycarbonate and magnetite were major iron corrosion products...

  20. ROLE OF IRON (II, III) HYDROXYCARBONATE GREEN RUST IN ARSENIC REMEDIATION USING ZEROVALENT IRON IN COLUMN TESTS

    EPA Science Inventory

    We examined corrosion products of zerovalent iron (Peerless iron) that was used in three column tests for removing arsenic under dynamic flow conditions with and without added phosphate and silicate. Iron(II, III) hydroxycarbonate and magnetite were major iron corrosion products...

  1. Corrosion and Passivation Studies of Iron and Ferrous Alloys

    DTIC Science & Technology

    1981-12-15

    combined cyclic voltammetry and rotatinq ring disk electrode have been used in different pH of borate or - ver) DD IFJAN113 1473 EDITION OF I NOV SS IS...OBSOLETE Unclassified S/N 0102- LF- 014- 6601 SECURITY CLASSIFICATION OF THIS PAGE (UWen Dora Entered) ii 20. buffer solution. Both cyclic voltammetry ...IV. Results and Discussion 76Si1. The Raman Spectrum of Borate Buffer Solution (pH 8.4) 76 2. Raman Spectrum of the Cathodically Protected Iron Surface

  2. Corrosion protection

    DOEpatents

    Brown, Donald W.; Wagh, Arun S.

    2003-05-27

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

  3. Evaluation of Iron Aluminide Weld Overlays for Erosion-Corrosion Resistant Boiler Tube Coatings in Low NOx Boilers

    SciTech Connect

    Regina, J.R.

    2000-05-16

    Iron aluminide weld overlays containing ternary additions and thermal spray coatings are being investigated for corrosion protection of boiler tubes in Low NOx burners. The primary objective of the research is to identify overlay and thermal spray compositions that provide corrosion protection of waterwall boiler tubes. In the current phase of work, preliminary corrosion tests were conducted on a binary Fe-Al alloy in multiple complex gases to determine which gases will be used for testing of the ternary alloys. Preliminary solid-state corrosion tests were also conducted to simulate slag-metal interactions seen in Low NOx furnaces. Two powder compositions were chosen for testing of the ternary alloys. A matrix of alloys to be tested in both gaseous and solid-state corrosion experiments was produced based on corrosion literature.

  4. Use of ion beam analysis techniques to characterise iron corrosion under water radiolysis

    NASA Astrophysics Data System (ADS)

    Lapuerta, S.; Moncoffre, N.; Millard-Pinard, N.; Mendes, E.; Corbel, C.; Crusset, D.

    2005-10-01

    The aim of this paper is to study the effect of water radiolysis under 12 MeV proton irradiation on the corrosion behaviour of pure iron. Oxygen and hydrogen playing a crucial role during the corrosion process have been specifically investigated. Heavy desaerated water (enriched at 99.9% in D) was also used to determine the origin of hydrogen at the iron surface. Proton irradiations were performed at the CERI cyclotron in Orléans. Both sides of the Fe foil (respectively in contact with air and with water) were analysed with ion beam techniques: alpha Rutherford backscattering spectrometry was used to profile oxygen, elastic recoil detection analysis has allowed to profile hydrogen. The use of D2O gives evidence that the hydrogen concentration present on the water face could originate from wet air. In addition, in case of the aerated deionised H2O media, it is shown that the irradiation process induces a strong corrosion. Scanning electron microscopy experiments confirm the formation of oxide precipitates.

  5. Properties of colloidal corrosion products and their effects on nuclear plants. Volume 1. Executive summary. Final report. [PWR; BWR

    SciTech Connect

    Matijevic, E.

    1982-10-01

    The properties of aqueous dispersions of finely divided oxides of iron, nickel, cobalt, chromium, and copper are described in overview fashion. More detailed aspects of this work will be found in a separate, larger report, NP-2606, Volume 2. The properties of these oxide corrosion products of importance to nuclear reactor water system technology are emphasized: adhesion, desorption, dissolution, transformation, and adsorption of dissolved species such as Co/sup 60/ ions. The work is fundamental to many LWR problems - radiation transport to piping surfaces, avoidance of crud buildup on nuclear fuel rods, decontamination and chemical cleaning of heat exchangers, and control of corrosion of piping.

  6. Facile fabrication of iron-based superhydrophobic surfaces via electric corrosion without bath

    NASA Astrophysics Data System (ADS)

    Sun, Qinghe; Liu, Hongtao; Chen, Tianchi; Wei, Yan; Wei, Zhu

    2016-04-01

    Superhydrophobic surface is of wide application in the field of catalysis, lubrication, waterproof, biomedical materials, etc. The superhydrophobic surface based on hard metal is worth further study due to its advantages of high strength and wear resistance. This paper investigates the fabrication techniques towards superhydrophobic surface on carbon steel substrate via electric corrosion and studies the properties of as-prepared superhydrophobic surface. The hydrophobic properties were characterized by a water sliding angle (SA) and a water contact angle (CA) measured by the Surface tension instrument. A Scanning electron microscope was used to analyze the structure of the corrosion surface. The surface compositions were characterized by an Energy Dispersive Spectrum. The Electrochemical workstation was used to measure its anti-corrosion property. The anti-icing performance was characterized by a steam-freezing test in Environmental testing chamber. The SiC sandpaper and 500 g weight were used to test the friction property. The research result shows that the superhydrophobic surface can be successfully fabricated by electrocorrosion on carbon steel substrate under appropriate process; the contact angle of the as-prepared superhydrophobic surface can be up to 152 ± 0.5°, and the sliding angle is 1-2°; its anti-corrosion property, anti-icing performance and the friction property all show an excellent level. This method provides the possibility of industrialization of superhydrophobic surface based on iron substrate as it can prepare massive superhydrophobic surface quickly.

  7. Aqueous Corrosion of Phosphide Minerals from Iron Meteorites: A Highly Reactive Source of Prebiotic Phosphorus on the Surface of the Early Earth

    NASA Astrophysics Data System (ADS)

    Pasek, Matthew A.; Lauretta, Dante S.

    2005-08-01

    We present the results of an experimental study of aqueous corrosion of Fe-phosphide under conditions relevant to the early Earth. The results strongly suggest that iron meteorites were an important source of reactive phosphorus (P), a requirement for the formation of P-based life. We further demonstrate that iron meteorites were an abundant source of phosphide minerals early in Earth history. Phosphide corrosion was studied in five different solutions: deionized water, deionized water buffered with sodium bicarbonate, deionized water with dissolved magnesium and calcium chlorides, deionized water containing ethanol and acetic acid, and deionized water containing the chlorides, ethanol, and acetic acid. Experiments were performed in the presence of both air and pure Ar gas to evaluate the effect of atmospheric chemistry. Phosphide corrosion in deionized water results in a metastable mixture of mixed-valence, P-bearing ions including pyrophosphate and triphosphate, key components for metabolism in modern life. In a pH-buffered solution of NaHCO3, the condensed and reduced species diphosphonate is an abundant corrosion product. Corrosion in ethanol- and acetic acid-containing solutions yields additional P-bearing organic molecules, including acetyl phosphonate and a cyclic triphosphorus molecule. Phosphonate is a major corrosion product of all experiments and is the only P-bearing molecule that persists in solutions with high concentrations of magnesium and calcium chlorides, which suggests that phosphonate may have been a primitive oceanic source of P. The stability and reactivity of phosphonate and hypophosphite in solution were investigated to elucidate reaction mechanisms and the role of mineral catalysts on P-solution chemistry. Phosphonate oxidation is rapid in the presence of Fe metal but negligible in the presence of magnetite and in the control sample. The rate of hypophosphite oxidation is independent of reaction substrate.

  8. Aqueous corrosion of phosphide minerals from iron meteorites: a highly reactive source of prebiotic phosphorus on the surface of the early Earth.

    PubMed

    Pasek, Matthew A; Lauretta, Dante S

    2005-08-01

    We present the results of an experimental study of aqueous corrosion of Fe-phosphide under conditions relevant to the early Earth. The results strongly suggest that iron meteorites were an important source of reactive phosphorus (P), a requirement for the formation of P-based life. We further demonstrate that iron meteorites were an abundant source of phosphide minerals early in Earth history. Phosphide corrosion was studied in five different solutions: deionized water, deionized water buffered with sodium bicarbonate, deionized water with dissolved magnesium and calcium chlorides, deionized water containing ethanol and acetic acid, and deionized water containing the chlorides, ethanol, and acetic acid. Experiments were performed in the presence of both air and pure Ar gas to evaluate the effect of atmospheric chemistry. Phosphide corrosion in deionized water results in a metastable mixture of mixed-valence, P-bearing ions including pyrophosphate and triphosphate, key components for metabolism in modern life. In a pH-buffered solution of NaHCO(3), the condensed and reduced species diphosphonate is an abundant corrosion product. Corrosion in ethanol- and acetic acid-containing solutions yields additional P-bearing organic molecules, including acetyl phosphonate and a cyclic triphosphorus molecule. Phosphonate is a major corrosion product of all experiments and is the only P-bearing molecule that persists in solutions with high concentrations of magnesium and calcium chlorides, which suggests that phosphonate may have been a primitive oceanic source of P. The stability and reactivity of phosphonate and hypophosphite in solution were investigated to elucidate reaction mechanisms and the role of mineral catalysts on P-solution chemistry. Phosphonate oxidation is rapid in the presence of Fe metal but negligible in the presence of magnetite and in the control sample. The rate of hypophosphite oxidation is independent of reaction substrate.

  9. 78 FR 15376 - Determinations: Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-11

    ... COMMISSION Determinations: Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea On the basis...)), that revocation of the countervailing duty order on corrosion-resistant carbon steel flat products from Korea and the antidumping duty orders on corrosion-resistant carbon steel flat products from Germany...

  10. Iron deficiency in outdoor pig production.

    PubMed

    Szabo, P; Bilkei, G

    2002-09-01

    It has been claimed that outdoor-reared suckling piglets do not need iron supplementation. According to practical experience, outdoor-reared and non-iron-supplemented piglets show a lower performance in comparison with their iron-supplemented counterparts. The purpose of the present study was to determine the effect of iron supplementation on outdoor-reared suckling piglets. In a large Hungarian outdoor pig production unit, 4691 piglets were assigned to one of two treatment groups. Piglets in group 1 (n = 2344): received no iron supplementation, whereas piglets in group 2 (n = 2347) were intramuscularly injected in the neck on day 3 post-partum with 1.5 ml of Ferriphor 10% solution (TAD Pharmaceutical GmbH, Bremerhaven, Germany). Animal weights, morbidity, haemoglobin concentration and mortality were recorded and analysed. At weaning the iron-injected piglets were significantly (P < 0.05) heavier. The iron-supplemented piglets also revealed significantly (P < 0.01) less pre-weaning morbidity and mortality and higher (P < 0.01) blood haemoglobin concentration compared with the non-injected ones. This study suggests that in order to prevent pre-weaning losses and support piglet health and weight performance, iron supplementation should be administered to piglets in outdoor pig production units.

  11. Effects of initial iron corrosion rate on long-term performance of iron permeable reactive barriers: column experiments and numerical simulation.

    PubMed

    suk O, Jin; Jeen, Sung-Wook; Gillham, Robert W; Gui, Lai

    2009-01-26

    Column experiments and numerical simulation were conducted to test the hypothesis that iron material having a high corrosion rate is not beneficial for the long-term performance of iron permeable reactive barriers (PRBs) because of faster passivation of iron and greater porosity loss close to the influent face of the PRBs. Four iron materials (Connelly, Gotthart-Maier, Peerless, and ISPAT) were used for the column experiments, and the changes in reactivity toward cis-dichloroethene (cis-DCE) degradation in the presence of dissolved CaCO3 were evaluated. The experimental results showed that the difference in distribution of the accumulated precipitates, resulting from differences in iron corrosion rate, caused a difference in the migration rate of the cis-DCE profiles and a significant difference in the pattern of passivation, indicating a faster passivation in the region close to the influent end for the material having a higher corrosion rate. For the numerical simulation, the accumulation of secondary minerals and reactivity loss of iron were coupled using an empirically-derived relationship that was incorporated into a multi-component reactive transport model. The simulation results provided a reasonable representation of the evolution of iron reactivity toward cis-DCE treatment and the changes in geochemical conditions for each material, consistent with the observed data. The simulations for long-term performance were also conducted to further test the hypothesis and predict the differences in performance over a period of 40 years under typical groundwater conditions. The predictions showed that the cases of higher iron corrosion rates had earlier cis-DCE breakthrough and more reduction in porosity starting from near the influent face, due to more accumulation of carbonate minerals in that region. Therefore, both the experimental and simulation results appear to support the hypothesis and suggest that reactivity changes of iron materials resulting from

  12. Synthesis and Corrosion Study of Zirconia-Coated Carbonyl Iron Particles

    SciTech Connect

    Shen, R.; Shafrir, S.N.; Miao, C.; Wang, M.; Lambropoulos, J.C.; Jacobs, S.D.; Yang, H.

    2010-01-07

    This paper describes the surface modification of micrometer-sized magnetic carbonyl iron particles (CI) with zirconia from zirconium(IV) butoxide using a sol–gel method. Zirconia shells with various thicknesses and different grain sizes and shapes are coated on the surface of CI particles by changing the reaction conditions, such as the amounts of zirconia sol, nitric acid, and CI particles. A silica adhesive layer made from 3-aminopropyl trimethoxysilane (APTMS) can be introduced first onto the surface of CI particles in order to adjust both the size and the shape of zirconia crystals, and thus the roughness of the coating. The microanalyses on these coated particles are studied by field-emission scanning electron microscopy (FE-SEM) and X-ray-diffraction (XRD). Accelerated acid corrosion and air oxidation tests indicate that the coating process dramatically improved oxidation and acid corrosion resistances, which are critical issues in various applications of CI magnetic particles.

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

    PubMed

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

    2001-01-01

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

  14. Enhanced Cr(VI) removal from groundwater by Fe(0)-H2O system with bio-amended iron corrosion.

    PubMed

    Yin, Weizhao; Li, Yongtao; Wu, Jinhua; Chen, Guocai; Jiang, Gangbiao; Li, Ping; Gu, Jingjing; Liang, Hao; Liu, Chuansheng

    2017-02-27

    A one-pot bio-iron system was established to investigate synergetic abiotic and biotic effects between iron and microorganisms on Cr(VI) removal. More diverse iron corrosion and reactive solids, such as green rusts, lepidocrocite and magnetite were found in the bio-iron system than in the Fe(0)-H2O system, leading to 4.3 times higher Cr(VI) removal efficiency in the bio-iron system than in the Fe(0)-H2O system. The cycling experiment also showed that the Cr(VI) removal capacity of Fe(0) in the bio-iron system was 12.4 times higher than that in the Fe(0)-H2O system. A 62days of life-span could be achieved in the bio-iron system, while the Fe(0)-H2O system lost its efficacy after 30days. Enhanced effects of extra Fe(2+) on Cr(VI) removal was observed, largely contributed to the adsorbed Fe(2+) on iron surface, which could function as an extra reductant for Cr(VI) and promote the electron transfer on the solid phase. The results also showed that the reduction of Cr(VI) by microorganisms was insignificant, indicating the adsorption/co-precipitation of Cr by iron oxides on iron surface was responsible for the overall Cr(VI) removal. Our study demonstrated that the bio-amended iron corrosion could improve the performance of Fe(0) for Cr(VI) removal from groundwater.

  15. Stress corrosion cracking susceptibilities of Fe3Al-based iron aluminides

    NASA Astrophysics Data System (ADS)

    Kim, Jung-Gu

    1995-04-01

    The susceptibilities to stress corrosion cracking (SCC) were investigated using the constant-potential U-bend SCC test. U-bend SCC evaluations were conducted on two iron aluminide compositions based on Fe3Al and containing 2 and 5 at.% Cr in acid-chloride (pH = 4200 ppm Cl), thiosulfate, and tetrathionate solutions at the freely-corroding conditions. Cracking failures occurred in the thiosulfate and tetrathionate solutions, but not in the acid-chloride solution. The iron aluminides were very susceptible to the sulfur-bearing environments in terms of SCC and aqueous corrosion characteristics. To investigate the effect of applied potential on the cracking behavior, U-bend tests were conducted in the acid-chloride solution at an anodic pitting potential and at cathodic hydrogen-evolution potentials. Cracking occurred within 200 h only at the highly negative cathodic potentials and only for the lower Cr composition. These results indicated that two iron aluminides investigated are susceptible to SCC in acid-chloride solution if the corrosion potential is sufficiently active to generate hydrogen, that the cracking mechanism was related to hydrogen embrittlement. The resistance to hydrogen embrittlement cracking increased with increasing Cr content, i.e., higher Cr levels were beneficial in minimizing this form of cracking. Increased resistance to cracking for the U-bend specimens is influenced by the chemical composition of the passive film. Metallographic examinations by scanning electron microscopy revealed that increasing Cr content decreased the proportion of transgranular cleavage cracking and increased the proportion of intergranular cracking.

  16. Corrosion behavior of surface films on boron-implanted high purity iron and stainless steels

    NASA Technical Reports Server (NTRS)

    Kim, H. J.; Carter, W. B.; Hochman, R. F.; Meletis, E. I.

    1985-01-01

    Boron (dose, 2 x 10 to the 17th ions/sq cm) was implanted into high purity iron, AISI 316 austenitic stainless steel, and AISI 440C martensitic stainless steel, at 40 keV. The film structure of implanted samples was examined and characterized by contrast and diffraction analyses utilizing transmission electron microscopy. The effect of B(+) ion implantation on the corrosion behavior was studied using the potentiodynamic polarization technique. Tests were performed in deaerated 1 N H2SO4 and 0.1 M NaCl solutions. Scanning electron microscopy was used to examine the morphology of the corroded surfaces after testing.

  17. Corrosion behavior of surface films on boron-implanted high purity iron and stainless steels

    NASA Technical Reports Server (NTRS)

    Kim, H. J.; Carter, W. B.; Hochman, R. F.; Meletis, E. I.

    1985-01-01

    Boron (dose, 2 x 10 to the 17th ions/sq cm) was implanted into high purity iron, AISI 316 austenitic stainless steel, and AISI 440C martensitic stainless steel, at 40 keV. The film structure of implanted samples was examined and characterized by contrast and diffraction analyses utilizing transmission electron microscopy. The effect of B(+) ion implantation on the corrosion behavior was studied using the potentiodynamic polarization technique. Tests were performed in deaerated 1 N H2SO4 and 0.1 M NaCl solutions. Scanning electron microscopy was used to examine the morphology of the corroded surfaces after testing.

  18. High-temperature corrosion-resistant iron-aluminide (FeAl) alloys exhibiting improved weldability

    DOEpatents

    Maziasz, P.J.; Goodwin, G.M.; Liu, C.T.

    1996-08-13

    This invention relates to improved corrosion-resistant iron-aluminide intermetallic alloys. The alloys of this invention comprise, in atomic percent, from about 30% to about 40% aluminum alloyed with from about 0.1% to about 0.5% carbon, no more than about 0.04% boron such that the atomic weight ratio of boron to carbon in the alloy is in the range of from about 0.01:1 to about 0.08:1, from about 0.01 to about 3.5% of one or more transition metals selected from Group IVB, VB, and VIB elements and the balance iron wherein the alloy exhibits improved resistance to hot cracking during welding. 13 figs.

  19. High-temperature corrosion-resistant iron-aluminide (FeAl) alloys exhibiting improved weldability

    DOEpatents

    Maziasz, Philip J.; Goodwin, Gene M.; Liu, Chain T.

    1996-01-01

    This invention relates to improved corrosion-resistant iron-aluminide intermetallic alloys. The alloys of this invention comprise, in atomic percent, from about 30% to about 40% aluminum alloyed with from about 0.1% to about 0.5% carbon, no more than about 0.04% boron such that the atomic weight ratio of boron to carbon in the alloy is in the range of from about 0.01:1 to about 0.08:1, from about 0.01 to about 3.5% of one or more transition metals selected from Group IVB, VB, and VIB elements and the balance iron wherein the alloy exhibits improved resistance to hot cracking during welding.

  20. Effects of blending of desalinated and conventionally treated surface water on iron corrosion and its release from corroding surfaces and pre-existing scales.

    PubMed

    Liu, Haizhou; Schonberger, Kenneth D; Peng, Ching-Yu; Ferguson, John F; Desormeaux, Erik; Meyerhofer, Paul; Luckenbach, Heidi; Korshin, Gregory V

    2013-07-01

    This study examined effects of blending desalinated water with conventionally treated surface water on iron corrosion and release from corroding metal surfaces and pre-existing scales exposed to waters having varying fractions of desalinated water, alkalinities, pH values and orthophosphate levels. The presence of desalinated water resulted in markedly decreased 0.45 μm-filtered soluble iron concentrations. However, higher fractions of desalinated water in the blends were also associated with more fragile corroding surfaces, lower retention of iron oxidation products and release of larger iron particles in the bulk water. SEM, XRD and XANES data showed that in surface water, a dense layer of amorphous ferrihydrite phase predominated in the corrosion products. More crystalline surface phases developed in the presence of desalinated water. These solid phases transformed from goethite to lepidocrocite with increased fraction of desalinated water. These effects are likely to result from a combination of chemical parameters, notably variations of the concentrations of natural organic matter, calcium, chloride and sulfate when desalinated and conventionally treated waters are blended.

  1. Physicochemical Characterization of Iron Carbohydrate Colloid Drug Products.

    PubMed

    Zou, Peng; Tyner, Katherine; Raw, Andre; Lee, Sau

    2017-07-31

    Iron carbohydrate colloid drug products are intravenously administered to patients with chronic kidney disease for the treatment of iron deficiency anemia. Physicochemical characterization of iron colloids is critical to establish pharmaceutical equivalence between an innovator iron colloid product and generic version. The purpose of this review is to summarize literature-reported techniques for physicochemical characterization of iron carbohydrate colloid drug products. The mechanisms, reported testing results, and common technical pitfalls for individual characterization test are discussed. A better understanding of the physicochemical characterization techniques will facilitate generic iron carbohydrate colloid product development, accelerate products to market, and ensure iron carbohydrate colloid product quality.

  2. Mechanism and kinetics of halogenated compound removal by metallic iron: Transport in solution, diffusion and reduction within corrosion films.

    PubMed

    Tang, Shun; Wang, Xiao-Mao; Liu, Shi-Ting; Yang, Hong-Wei; Xie, Yuefeng F; Yang, Xiao-Yi

    2017-03-06

    A detailed kinetic model comprised of mass transport (ktra), pore diffusion (kdif), adsorption and reduction reaction (krea), was developed to quantitatively evaluate the effect of corrosion films on the removal rate (kobs) of halogenated compounds by metallic iron. Different corrosion conditions were controlled by adjusting the iron aging time (0 or 1 yr) and dissolved oxygen concentration (0-7.09 mg/L DO). The kobs values for bromate, mono-, di- and tri-chloroacetic acids (BrO3(-), MCAA, DCAA and TCAA) were 0.41-7.06, 0-0.16, 0.01-0.53, 0.10-0.73 h(-1), with ktra values at 13.32, 12.12, 11.04 and 10.20 h(-1), kdif values at 0.42-5.82, 0.36-5.04, 0.30-4.50, 0.30-3.90 h(-1), and krea values at 14.94-421.18, 0-0.19, 0.01-1.30, 0.10-3.98 h(-1), respectively. The variation of kobs value with reaction conditions depended on the reactant species, while those of ktra, kdif and krea values were irrelevant to the species. The effects of corrosion films on kdif and krea values were responsible for the variation of kobs value for halogenated compounds. For a mass-transfer-limited halogenated compound such as BrO3(-), an often-neglected kdif value primarily determined its kobs value when pore diffusion was the rate-limiting step of its removal. In addition, the value of kdif might influence product composition during a consecutive dechlorination, such as for TCAA and DCAA. For a reaction-controlled compound such as MCAA, an increased krea value was achieved under low oxic conditions, which was favorable to improve its kobs value. The proposed model has a potential in predicting the removal rate of halogenated compounds by metallic iron under various conditions.

  3. Microstructure, corrosion properties and bio-compatibility of calcium zinc phosphate coating on pure iron for biomedical application.

    PubMed

    Chen, Haiyan; Zhang, Erlin; Yang, Ke

    2014-01-01

    In order to improve the biocompatibility and the corrosion resistance in the initial stage of implantation, a phosphate (CaZn2(PO4)2·2H2O) coating was obtained on the surface of pure iron by a chemical reaction method. The anti-corrosion property, the blood compatibility and the cell toxicity of the coated pure iron specimens were investigated. The coating was composed of some fine phosphate crystals and the surface of coating was flat and dense enough. The electrochemical data indicated that the corrosion resistance of the coated pure iron was improved with the increase of phosphating time. When the specimen was phosphated for 30min, the corrosion resistance (Rp) increased to 8006 Ω. Compared with that of the naked pure iron, the anti-hemolysis property and cell compatibility of the coated specimen was improved significantly, while the anti-coagulant property became slightly worse due to the existence of element calcium. It was thought that phosphating treatment might be an effective method to improve the biocompatibility of pure iron for biomedical application.

  4. High-temperature corrosion of iron-aluminum and iron-aluminum-yttrium alloys

    NASA Astrophysics Data System (ADS)

    Insoo, Kim

    The high-temperature corrosion behavior of Fe3Al alloy has been investigated by conducting two studies: (1) corrosion of Fe 3Al and Fe3Al-Y alloys in oxidizing atmosphere and (2) corrosion of Fe3Al in mixed chlorine/oxygen environments. In the first study, oxidation of the two alloys, Fe-14.3 wt% Al and Fe-14.1 wt% Al-0.3 wt% Y, was carried out in the temperature range of 800 to 1100°C to investigate the general oxidation behavior of Fe3Al and the effect of yttrium on the oxidation of Fe3Al in terms of oxidation kinetics, oxide scale adhesion and microstructure. At lower temperatures (<1000°C), the oxidation rate of the two alloys was nearly identical, and the parabolic rate constant obtained as a function of temperature was Kp = 5128 exp[--39500 (cal/mol)/RT] mg2/cm4 h. At higher temperatures, however, yttrium-added Fe3Al alloy exhibited lower oxidation rate and much more improved oxide adhesion. The lower oxidation rate observed in Fe3Al-Y alloy seems to be due to the followings: (1) a decrease in aluminum diffusion through alumina scale and (2) modification of the scale growth mechanism from simultaneous countercurrent diffusion of aluminum and oxygen to predominant inward diffusion of oxygen, which generates less growth stress and thus prevents the formation of fast diffusion paths such as microcracks. The adhesion improvement of alumina scale formed on the Fe3Al-Y was attributed to the modification of alumina growth mechanism by the addition of Y to the Fe3Al alloy. The change of growth mechanism leads to the formation of pegs, decrease of the oxide growth stress, and decrease of voids formation, which enhances the adhesion of alumina scale to the Fe3Al alloy. The second study has focused on the corrosion of Fe3Al in the temperature range of 600--800°C in Cl2-Ar gas mixtures containing traces of oxygen as an impurity. Weight gain was observed during the corrosion of Fe3Al at 600°C in 0.25% Cl2-Ar, which is due to the formation of Fe2O3, while continuous

  5. Influence of multi-element ion beam bombardment on the corrosion behavior of iron and steel

    SciTech Connect

    Wei, Tian; Run, Wu; Weiping, Cai; Rutao, Wang ); Godechot, X.; Brown, I. )

    1991-06-01

    The effect of multi-element ion implantation on the corrosion resistance to acid solution has been studied for stainless steel, medium carbon steel, pure iron, and chromium-deposited iron. The implanted elements were Cu, Mo, Cr, Ni, Yb and Ti at doses of each species of from 5 {times} 10{sup 15} to 1 {times} 10{sup 17} cm{sup {minus}2} and at ion energies of up to 100 keV. The stainless steel used was 18-8 Cr-Ni, and the medium carbon steel was 0.45% C. The implanted samples were soaked in dilute sulfuric acid solution for periods up to 48 hours and the weight loss measured by atomic absorption spectroscopy. The kinetic parameter values describing the weight loss as a function of time were determined for all samples. In this paper we summarize the corrosion resistance behavior for the various different combinations of implanted species, doses, and substrates. The influence of the composition and structure of the modified surface layer is discussed.8 refs., 5 figs., 2 tabs.

  6. Effects of iron-reducing bacteria on carbon steel corrosion induced by thermophilic sulfate-reducing consortia.

    PubMed

    Valencia-Cantero, Eduardo; Peña-Cabriales, Juan José

    2014-02-28

    Four thermophilic bacterial species, including the iron-reducing bacterium Geobacillus sp. G2 and the sulfate-reducing bacterium Desulfotomaculum sp. SRB-M, were employed to integrate a bacterial consortium. A second consortium was integrated with the same bacteria, except for Geobacillus sp. G2. Carbon steel coupons were subjected to batch cultures of both consortia. The corrosion induced by the complete consortium was 10 times higher than that induced by the second consortium, and the ferrous ion concentration was consistently higher in iron-reducing consortia. Scanning electronic microscopy analysis of the carbon steel surface showed mineral films colonized by bacteria. The complete consortium caused profuse fracturing of the mineral film, whereas the non-iron-reducing consortium did not generate fractures. These data show that the iron-reducing activity of Geobacillus sp. G2 promotes fracturing of mineral films, thereby increasing steel corrosion.

  7. Biodegradation of corrosion inhibitors and their influence on petroleum product pipeline.

    PubMed

    Rajasekar, Aruliah; Maruthamuthu, Sundaram; Palaniswamy, Narayanan; Rajendran, Annamalai

    2007-01-01

    The present study enlightens the role of Bacillus cereus ACE4 on biodegradation of commercial corrosion inhibitors (CCI) and the corrosion process on API 5LX steel. Bacillus cereus ACE4, a dominant facultative aerobic species was identified by 16S rDNA sequence analysis, which was isolated from the corrosion products of refined diesel-transporting pipeline in North West India. The effect of CCI on the growth of bacterium and its corrosion inhibition efficiency were investigated. Corrosion inhibition efficiency was studied by rotating cage test and the nature of biodegradation of corrosion inhibitors was also analyzed. This isolate has the capacity to degrade the aromatic and aliphatic hydrocarbon present in the corrosion inhibitors. The degraded products of corrosion inhibitors and bacterial activity determine the electrochemical behavior of API 5LX steel.

  8. Slippery liquid-infused porous surface based on perfluorinated lubricant/iron tetradecanoate: Preparation and corrosion protection application

    NASA Astrophysics Data System (ADS)

    Yang, Shengsheng; Qiu, Ri; Song, Hongqing; Wang, Peng; Shi, Zhiqiang; Wang, Yanfang

    2015-02-01

    Corrosion and fouling have been two major enemies for materials immersed in seawater. Fluid including gas and liquid as coating for marine corrosion protection has attracted much attention, since it can also exert antifouling capability in seawater environment. Combining gas and solid phases, superhydrophobic surface is promising to protect the underlying metal from corrosion. However, the intrinsically short sustainability in underwater environment has hindered its practical application, so that its corrosion protection ability is only temporary. Originated from liquid and solid phases, slippery liquid-infused porous surface (SLIPS) has spurred wide interest due to its prominent performance in different fields. However, the exploration of corrosion protection efficiency from SLIPS remains rare. In this research, SLIPS is constructed onto steel surface via a facile two-step protocol. First, based on a dissolution-deposition strategy, iron tetradecanoate is formed by an electrochemical route. After that, fluid lubricant is infused onto the deposit, whose rough surface acts as the reservoir to entrap the fluid to form a static liquid coating. Compared to the bare and hydrophobic deposit covering low alloy steel, the SLIPS composed perfluorinated lubricant and iron tetradecanoate endows good corrosion protection property.

  9. High-temperature corrosion and applications of nickel and iron aluminides in coal-conversion power systems

    SciTech Connect

    Natesan, K.; Tortorelli, P.F.

    1996-10-01

    Nickel and iron aluminide intermetallics are being developed for use as structural materials and/or as cladding for conventional engineering alloys. In addition to strength advantages, these materials exhibit excellent resistance to corrosion in single- and multioxidant environments at elevated temperatures by the formation of slow-growing, adherent alumina scales. Corrosion resistance in a given environment is strongly dependent on the composition of the alloy and on the nature of the corrosive species prevalent in the service environment. This paper presents a comprehensive review of the current status of the corrosion performance of these intermetallics in oxidizing, sulfidizing, and multicomponent gas environments of typical coal-conversion systems. Mechanisms of scale development/breakdown, performance envelopes for long-term usage of these materials, approaches to modifying the surfaces of engineering alloys by cladding or coating them with intermetallics, and in-service experience with these materials are emphasized.

  10. Characterization of corrosion products formed on different surfaces of steel exposed to simulated groundwater solution

    NASA Astrophysics Data System (ADS)

    Xu, Qiufa; Gao, Kewei; Wang, Yanbin; Pang, Xiaolu

    2015-08-01

    The corrosion behavior of a low alloy steel in simulated groundwater was investigated. The upward surface of the steel underwent more serious corrosion than the downward surface. The corrosion products formed on the upward and downward surfaces were characterized by SEM, EDX, and XRD, and the electrochemical properties of bare and rusted samples were analyzed. The difference in the corrosion rates of the different surfaces of the steel could be attributed to the potential difference between the upward and downward surfaces as well as the higher amount of CaCO3 deposits on the downward surface leading to a compact corrosion product.

  11. Examination of Corrosion Products and the Alloy Surface After Crevice Corrosion of a Ni-Cr-Mo- Alloy

    SciTech Connect

    X. Shan; J.H. Payer

    2006-06-09

    The objective of this study is to investigate the composition of corrosion products and the metal surface within a crevice after localized corrosion. The analysis provides insight into the propagation, stifling and arrest processes for crevice corrosion and is part of a program to analyze the evolution of localized corrosion damage over long periods of time, i.e. 10,000 years and longer. The approach is to force the initiation of crevice corrosion by applying anodic polarization to a multiple crevice assembly (MCA). Results are reported here for alloy C-22, a Ni-Cr-Mo alloy, exposed to a high temperature, concentrated chloride solution. Controlled crevice corrosion tests were performed on C-22 under highly aggressive, accelerated condition, i.e. 4M NaCl, 100 C and anodic polarization to -0.15V-SCE. The crevice contacts were by either a polymer tape (PTFE) compressed by a ceramic former or by a polymer (PTFE) crevice former. Figure 1 shows the polarization current during a crevice corrosion test. After an incubation period, several initiation-stifle-arrest events were indicated. The low current at the end of the test indicated that the metal surface had repassivated.

  12. Surface analysis and depth profiling of corrosion products formed in lead pipes used to supply low alkalinity drinking water.

    PubMed

    Davidson, C M; Peters, N J; Britton, A; Brady, L; Gardiner, P H E; Lewis, B D

    2004-01-01

    Modern analytical techniques have been applied to investigate the nature of lead pipe corrosion products formed in pH adjusted, orthophosphate-treated, low alkalinity water, under supply conditions. Depth profiling and surface analysis have been carried out on pipe samples obtained from the water distribution system in Glasgow, Scotland, UK. X-ray diffraction spectrometry identified basic lead carbonate, lead oxide and lead phosphate as the principal components. Scanning electron microscopy/energy-dispersive x-ray spectrometry revealed the crystalline structure within the corrosion product and also showed spatial correlations existed between calcium, iron, lead, oxygen and phosphorus. Elemental profiling, conducted by means of secondary ion mass spectrometry (SIMS) and secondary neutrals mass spectrometry (SNMS) indicated that the corrosion product was not uniform with depth. However, no clear stratification was apparent. Indeed, counts obtained for carbonate, phosphate and oxide were well correlated within the depth range probed by SIMS. SNMS showed relationships existed between carbon, calcium, iron, and phosphorus within the bulk of the scale, as well as at the surface. SIMS imaging confirmed the relationship between calcium and lead and suggested there might also be an association between chloride and phosphorus.

  13. Scanning Electrochemical Microscopy for the Investigation of Galvanic Corrosion of Iron with Zinc in 0.1 M NaCl Solution

    NASA Astrophysics Data System (ADS)

    Joseph Raj, X.; Nishimura, T.

    2016-02-01

    Scanning electrochemical microscopy was used to monitor microscopic aspects of the electrochemical processes at the iron-zinc couple immersed in 0.1 M NaCl aqueous solution. The SECM measured the concentration of chemical species relevant to the corrosion processes. The electrochemical behavior of galvanic Fe/Zn coupling was investigated as a function of time using SECM microelectrode both as Fe/Zn joined together as well as away from each other. SECM amperometric line scan curves were obtained over the Fe/Zn at a constant distance. In the first case, the chemical species participating in the corrosion reactions at the sample are detected at the SECM tip by applying appropriate potential values to the microelectrode. The release of Zn2+ ionic species into the solution phase from local anodic sites, as well as the consumption of dissolved oxygen at the corresponding cathodic locations, was successfully monitored. The results revealed that the galvanic couple where Fe/Zn is close to each other will show higher corrosion rate of zinc than that of galvanic couple away from each other. The Fe/Zn couple away from each other showed a decrease in current values with time. This is due to the formation of oxide layer of Zn over the Fe followed by the protection of the corrosion products with further exposure times.

  14. Electromagnetic absorbing property of the flaky carbonyl iron particles by chemical corrosion process

    NASA Astrophysics Data System (ADS)

    Zheng, Dianliang; Liu, Ting; Zhou, Li; Xu, Yonggang

    2016-12-01

    The flaky carbonyl iron particles (CIPs) were prepared using a milling process at the first step, then the chemical corrosion process was done to optimize the particle shape. The particle morphology was characterized by the scanning electron microscopy, the static magnetic property was evaluated on a vibrating sample magnetometer and X-ray diffraction (XRD) patterns were done to analyze the particle crystal grain structure. The complex permittivity and permeability were measured using a vector network analyzer in the frequency range of 2-18 GHz and the reflection loss (RL) was calculated. The results showed that the saturation magnetization value of the CIPs decreased as the CIPs was corroded to the small flakes in chemical corrosion process. The diffraction peaks of the single α-Fe existed in the XRD pattern of CIPs, and the characteristic peaks was more obvious and the intensity of the diffraction pattern was lower by corrosion. The permittivity and the permeability of the corroded milling CIPs was a little larger than the milling CIPs, it was due to the larger aspect ratio based on the fitting calculation process. At thickness 0.6 mm and 0.8 mm, the corroded milling CIPs composite had the better absorbing property than the other two samples. The frequency band (RL<-5 dB) could be widened to 8.96-18 GHz at 0.6 mm and 5.92-18 GHz at 0.8 mm, and RL less than -8 dB began to exist in 8.96-14.72 GHz at 0.8 mm.

  15. Corrosion fatigue of iron-chromium-nickel alloys: Fracture mechanics, microstructure and chemistry

    SciTech Connect

    Wei, R.P.

    1992-01-29

    This progress report briefly summarizes the research performed under the referenced grant for the period from 1 December 1990 to 31 December 1991, and contains a cumulative listing of technical presentations and publications dating back to 1 June 1988. Under this grant, a multi-disciplinary research program is undertaken to address certain fundamental issues relating to corrosion fatigue crack growth in structurally important alloys in aqueous environments. The principal goal of the research is to develop and expand the scientific understanding of the processes that control corrosion fatigue crack growth, particularly for ferrous alloys in terms of the controlling mechanical and chemical/electrochemical processes and their interactions with the microstructure. Focus is placed upon the austenitic iron-chromium-nickel (FeCrNi) alloys because of the need to resolve certain mechanistic issues and because of extensive utilization of these alloys in the power generation and chemical industries. Emphasis is given to the growth of short (small) cracks at low growth rates because crack growth in this regime is expected to be more sensitive to changes in external chemical/electrochemical variables.

  16. Erosion-Corrosion of Iron and Nickel Alloys at Elevated Temperature in a Combustion Gas Environment

    SciTech Connect

    Tylczak, Joseph

    2014-05-02

    This paper reports on the results of a study that compares the erosion-corrosion behavior of a variety of alloys (Fe- 2¼Cr 1Mo, 304 SS, 310 SS, Incoloy 800, Haynes 230 and a Fe3Al) in a combustion environment. Advanced coal combustion environments, with higher temperatures, are driving re-examination of traditional and examination of new alloys in these hostile environments. In order to simulate conditions in advanced coal combustion boilers, a special erosion apparatus was used to allow for impingement of particles under a low abrasive flux in a gaseous environment comprised of 20 % CO2, 0.05 % HCl, 77 % N2, 3 % O2, and 0.1 % SO2. Tests were conducted at room temperature and 700 °C with ~ 270 μm silica, using an impact velocity of 20 m/s in both air and the simulated combustion gas environment. The erosion-corrosion behavior was characterized by gravimetric measurements and by examination of the degraded surfaces optically and by scanning electron microscopy (SEM). At room temperature most of the alloys had similar loss rates. Not surprisingly, at 700 °C the lower chrome-iron alloy had a very high loss rate. The nickel alloys tended to have higher loss rates than the high chrome austenitic alloys.

  17. ARSENIC INTERACTION WITH IRON (II, III) HYDROXYCARBONATE GREEN RUST: IMPLICATIONS FOR ARSENIC REMEDIATION

    EPA Science Inventory

    Zerovalent iron is being used in permeable reactive barriers (PRBs) to remediate groundwater arsenic contamination. Iron(II, III) hydroxycarbonate green rust is a major corrosion product of zerovalent iron under anaerobic conditions. The interaction between arsenic and this green...

  18. ARSENIC INTERACTION WITH IRON (II, III) HYDROXYCARBONATE GREEN RUST: IMPLICATIONS FOR ARSENIC REMEDIATION

    EPA Science Inventory

    Zerovalent iron is being used in permeable reactive barriers (PRBs) to remediate groundwater arsenic contamination. Iron(II, III) hydroxycarbonate green rust is a major corrosion product of zerovalent iron under anaerobic conditions. The interaction between arsenic and this green...

  19. Iron Corrosion Induced by Nonhydrogenotrophic Nitrate-Reducing Prolixibacter sp. Strain MIC1-1

    PubMed Central

    Ito, Kimio; Wakai, Satoshi; Tsurumaru, Hirohito; Ohkuma, Moriya; Harayama, Shigeaki

    2014-01-01

    Microbiologically influenced corrosion (MIC) of metallic materials imposes a heavy economic burden. The mechanism of MIC of metallic iron (Fe0) under anaerobic conditions is usually explained as the consumption of cathodic hydrogen by hydrogenotrophic microorganisms that accelerates anodic Fe0 oxidation. In this study, we describe Fe0 corrosion induced by a nonhydrogenotrophic nitrate-reducing bacterium called MIC1-1, which was isolated from a crude-oil sample collected at an oil well in Akita, Japan. This strain requires specific electron donor-acceptor combinations and an organic carbon source to grow. For example, the strain grew anaerobically on nitrate as a sole electron acceptor with pyruvate as a carbon source and Fe0 as the sole electron donor. In addition, ferrous ion and l-cysteine served as electron donors, whereas molecular hydrogen did not. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain MIC1-1 was a member of the genus Prolixibacter in the order Bacteroidales. Thus, Prolixibacter sp. strain MIC1-1 is the first Fe0-corroding representative belonging to the phylum Bacteroidetes. Under anaerobic conditions, Prolixibacter sp. MIC1-1 corroded Fe0 concomitantly with nitrate reduction, and the amount of iron dissolved by the strain was six times higher than that in an aseptic control. Scanning electron microscopy analyses revealed that microscopic crystals of FePO4 developed on the surface of the Fe0 foils, and a layer of FeCO3 covered the FePO4 crystals. We propose that cells of Prolixibacter sp. MIC1-1 accept electrons directly from Fe0 to reduce nitrate. PMID:25548048

  20. Effect of surface condition on the aqueous corrosion behavior of iron aluminies

    SciTech Connect

    Buchanan, R.A.; Perrin, R.L.

    1995-08-01

    The effects of retained high-temperature surface oxides, produced during thermomechanical processing and/or heat treatment, on the aqueous-corrosion characteristics of Fe-Al-based alloys were evaluated by electrochemical methods. Cyclic anodic polarization evaluations were conducted at room temperature in a mild acid-chloride solution (pH = 4,200 ppm Cl{sup {minus}}) on the Fe{sub 3}Al-based iron aluminides, FA-84 (Fe-28Al-2Cr-0.05B, at %), FA-129 (Fe-28Al-5Cr-0.5Nb-0.2C, at %), and FAL-Mo (Fe-28Al-5Cr-1Mo-0.04B-0.08Zr, at %), on the FeAl-based iron aluminide, FA-385 (Fe-35.65Al-0.20Mo-0.05Zr-0.11C, at %). The surface conditions evaluated were: As received (i.e. with the retained high-temperature oxides), mechanically cleaned (ground through 600-grit SiC paper), and chemically cleaned (10% HNO{sub 3}, 2%HF, at 43 {degree}C). The principal electrochemical parameter of interest was the critical putting potential with lower values indicating less resistance to chloride-induced localized corrosion. For all materials evaluated, the critical pitting potential was found to be significantly lower in the as-received condition than in the mechanically-cleaned and chemically-cleaned conditions. Mechanisms responsible for the detrimental high-temperature-oxide effect are under study.

  1. Iron corrosion induced by nonhydrogenotrophic nitrate-reducing Prolixibacter sp. strain MIC1-1.

    PubMed

    Iino, Takao; Ito, Kimio; Wakai, Satoshi; Tsurumaru, Hirohito; Ohkuma, Moriya; Harayama, Shigeaki

    2015-03-01

    Microbiologically influenced corrosion (MIC) of metallic materials imposes a heavy economic burden. The mechanism of MIC of metallic iron (Fe(0)) under anaerobic conditions is usually explained as the consumption of cathodic hydrogen by hydrogenotrophic microorganisms that accelerates anodic Fe(0) oxidation. In this study, we describe Fe(0) corrosion induced by a nonhydrogenotrophic nitrate-reducing bacterium called MIC1-1, which was isolated from a crude-oil sample collected at an oil well in Akita, Japan. This strain requires specific electron donor-acceptor combinations and an organic carbon source to grow. For example, the strain grew anaerobically on nitrate as a sole electron acceptor with pyruvate as a carbon source and Fe(0) as the sole electron donor. In addition, ferrous ion and l-cysteine served as electron donors, whereas molecular hydrogen did not. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain MIC1-1 was a member of the genus Prolixibacter in the order Bacteroidales. Thus, Prolixibacter sp. strain MIC1-1 is the first Fe(0)-corroding representative belonging to the phylum Bacteroidetes. Under anaerobic conditions, Prolixibacter sp. MIC1-1 corroded Fe(0) concomitantly with nitrate reduction, and the amount of iron dissolved by the strain was six times higher than that in an aseptic control. Scanning electron microscopy analyses revealed that microscopic crystals of FePO4 developed on the surface of the Fe(0) foils, and a layer of FeCO3 covered the FePO4 crystals. We propose that cells of Prolixibacter sp. MIC1-1 accept electrons directly from Fe(0) to reduce nitrate.

  2. Technical investigation of a pyrophoric event involving corrosion products from HEU ZPPR fuel plates

    SciTech Connect

    Totemeier, T. C.

    2000-02-02

    A pyrophoric event recently occurred which involved corrosion products collected from highly-enriched uranium (HEU) fuel plates used in the Zero Power Physics Reactor (ZPPR). This paper summarizes the event and its background, and presents the results of an investigation into its source and mechanism. The investigation focused on characterization of corrosion product samples similar to those involved in the event using thermo-gravimetric analysis (TGA). Burning curve TGA tests were performed to measure the ignition temperature and hydride fractions of corrosion products in several different conditions to assess the effects of passivation treatment and long-term storage on chemical reactivity. The hydride fraction and ignition temperature of the corrosion products were found to be strongly dependent on the corrosion extent of the source metal. The results indicate that the energy source for the event was a considerable quantity of uranium hydride present in the corrosion products, but the specific ignition mechanism could not be identified.

  3. Characterization of uranium corrosion products involved in a uranium hydride pyrophoric event

    NASA Astrophysics Data System (ADS)

    Totemeier, T. C.

    2000-02-01

    Uranium metal corrosion products involved in a recent pyrophoric event were characterized using thermo-gravimetric analysis, X-ray diffraction, and BET gas sorption techniques to determine the effects of passivation treatment and long-term storage on chemical reactivity. Characterization was performed on corrosion products in three different conditions: immediately after separation from the source metal, after low-temperature passivation, and after passivation and extended vault storage. The hydride fraction and ignition temperature of the corrosion products were found to be strongly dependent on the corrosion extent of the source metal. There was little change in corrosion product properties resulting from low-temperature passivation or vault storage. The results indicate that the energy source for the pyrophoric event was a considerable quantity of uranium hydride present in the corrosion products, but the specific ignition mechanism could not be identified.

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

    PubMed

    Zuo, Rongjun; Wood, Thomas K

    2004-11-01

    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.

  5. Neutrophilic Iron-Oxidizing “Zetaproteobacteria” and Mild Steel Corrosion in Nearshore Marine Environments ▿ †

    PubMed Central

    McBeth, Joyce M.; Little, Brenda J.; Ray, Richard I.; Farrar, Katherine M.; Emerson, David

    2011-01-01

    Microbiologically influenced corrosion (MIC) of mild steel in seawater is an expensive and enduring problem. Little attention has been paid to the role of neutrophilic, lithotrophic, iron-oxidizing bacteria (FeOB) in MIC. The goal of this study was to determine if marine FeOB related to Mariprofundus are involved in this process. To examine this, field incubations and laboratory microcosm experiments were conducted. Mild steel samples incubated in nearshore environments were colonized by marine FeOB, as evidenced by the presence of helical iron-encrusted stalks diagnostic of the FeOB Mariprofundus ferrooxydans, a member of the candidate class “Zetaproteobacteria.” Furthermore, Mariprofundus-like cells were enriched from MIC biofilms. The presence of Zetaproteobacteria was confirmed using a Zetaproteobacteria-specific small-subunit (SSU) rRNA gene primer set to amplify sequences related to M. ferrooxydans from both enrichments and in situ samples of MIC biofilms. Temporal in situ incubation studies showed a qualitative increase in stalk distribution on mild steel, suggesting progressive colonization by stalk-forming FeOB. We also isolated a novel FeOB, designated Mariprofundus sp. strain GSB2, from an iron oxide mat in a salt marsh. Strain GSB2 enhanced uniform corrosion from mild steel in laboratory microcosm experiments conducted over 4 days. Iron concentrations (including precipitates) in the medium were used as a measure of corrosion. The corrosion in biotic samples (7.4 ± 0.1 mM) was significantly higher than that in abiotic controls (5.0 ± 0.1 mM). These results have important implications for the role of FeOB in corrosion of steel in nearshore and estuarine environments. In addition, this work shows that the global distribution of Zetaproteobacteria is far greater than previously thought. PMID:21131509

  6. M"ossbauer study of corrosion and abrasion products in oil transporting pipes

    NASA Astrophysics Data System (ADS)

    Gomez, Raul W.; Perez Mazariego, Jose Luis; Marquina, Vivianne; Marquina, Ma. Luisa; Ridaura, Rosalia; Martinez, Lorenzo

    2012-02-01

    It is known that one of the main technological problems in carbon steel oleoducts is the corrosion produced by different substances, such as water, carbon dioxide, sulfur, and microorganisms. In addition, if in such mixture there is sand, aggressive sludge can be form that abrasions material from the oleoduct. A room temperature M"ossbauer study of corroded material taken from different sites of oleoducts is presented. Most of the M"ossbauer spectra reveal the presence of nanoparticles, indicating that in these pipes the abrasion problem is severe. A preliminary identification of the oxidized samples suggests the presence of magnetite, and some Iron hydroxides. Further studies are in course in order to identify unambiguously the products present in the corroded materials.

  7. Effects of morpholine and boric acid implementation on secondary chemistry and corrosion product transport

    SciTech Connect

    Siegwarth, D.P.; Pearl, W.L.; Sawochka, S.G.; Clouse, M.E.

    1992-07-01

    This project expanded the database on the effects of morpholine use as a pH control additive in the secondary water system of pressurized water reactors. Tests carried out at Alabama Power`s Joseph M. Farley Units 1 and 2, Northern States Power`s Prairie Island Unit 2, and Commonwealth Edison`s Byron Unit 1 demonstrated that the use of morpholine reduced corrosion product transport in PWR secondary systems by up to a factor of 2. Further reductions were achieved by eliminating copper alloy tubing and increasing secondary cycles pH. Steam generator boric acid treatment in plants with all ferrous secondary cycles operated with morpholine was shown to have a minimal effect on iron transport.

  8. Effects of morpholine and boric acid implementation on secondary chemistry and corrosion product transport

    SciTech Connect

    Siegwarth, D.P.; Pearl, W.L.; Sawochka, S.G.; Clouse, M.E. )

    1992-07-01

    This project expanded the database on the effects of morpholine use as a pH control additive in the secondary water system of pressurized water reactors. Tests carried out at Alabama Power's Joseph M. Farley Units 1 and 2, Northern States Power's Prairie Island Unit 2, and Commonwealth Edison's Byron Unit 1 demonstrated that the use of morpholine reduced corrosion product transport in PWR secondary systems by up to a factor of 2. Further reductions were achieved by eliminating copper alloy tubing and increasing secondary cycles pH. Steam generator boric acid treatment in plants with all ferrous secondary cycles operated with morpholine was shown to have a minimal effect on iron transport.

  9. The influence of relative humidity on iron corrosion under proton irradiation

    NASA Astrophysics Data System (ADS)

    Lapuerta, S.; Bérerd, N.; Moncoffre, N.; Millard-Pinard, N.; Jaffrézic, H.; Crusset, D.; Féron, D.

    2008-03-01

    With regard to the storage for high-level radioactive waste and the reversible period of a geological repository, the influence of proton irradiation on the indoor atmospheric corrosion of iron has been investigated in relation to the relative humidity (RH) in the atmosphere. Irradiation experiments were performed using a 3-MeV extracted proton beam. Relative humidity varies from 0% to 85%. Before and after each irradiation, the surfaces of the sample were characterised by Rutherford backscattering spectrometry in order to determine oxygen concentrations in the metal. The maximum oxidation rate was observed for 45% RH in air under proton irradiation and was compared with literature data without irradiation where the maximum oxidation rate was observed at 95% RH. The experimental results are discussed on the basis of the Langmuir-Hinshelwood (LH) model: they are explained by the contrast between the adsorption of O 2 and H 2O species on the active cathodic sites of the iron surface and by the formation of H +(H 2O) n.

  10. Changes of the corrosion potential of iron in stagnation and flow conditions and their relationship with metal release.

    PubMed

    Fabbricino, Massimiliano; Korshin, Gregory V

    2014-10-01

    This study examined the behavior of corrosion potential (Ecorr) of iron exposed to drinking water during episodes of stagnation and flow. These measurements showed that during stagnation episodes, Ecorr values decrease prominently and consistently. This decrease is initially rapid but it becomes slower as the stagnation time increases. During flow episodes, the Ecorr values increase and reach a quasi-steady state. Experiments with varying concentrations of dissolved oxygen showed that the decrease of Ecorr values characteristic for stagnation is likely to be associated with the consumption of dissolved oxygen by the exposed metal. The corrosion potential of iron and its changes during stagnation were sensitive to the concentrations of sulfate and chloride ions. Measurements of iron release showed that both the absolute values of Ecorr measured prior to or after stagnation episodes were well correlated with the logarithms of concentrations of total iron. The slope of this dependence showed that the observed correlations between Ecorr values and Fe concentrations corresponded to the coupling between the oxidant consumption and changes of Fe redox status. These results demonstrate that in situ Ecorr measurements can be a sensitive method with which to ascertain effects of hydrodynamic conditions and short-term variations of water chemistry on metal release and corrosion in drinking water. This approach is valuable practically because Ecorr measurements are precise, can be carried out in situ with any desired time resolution, do not affect the state of exposed surface in any extent and can be carried out with readily available equipment.

  11. Study of MHD Corrosion and Transport of Corrosion Products of Ferritic/Martensitic Steels in the Flowing PbLi and its Application to Fusion Blanket

    NASA Astrophysics Data System (ADS)

    Saeidi, Sheida

    Two important components of a liquid breeder blanket of a fusion power reactor are the liquid breeder/coolant and the steel structure that the liquid is enclosed in. One candidate combination for such components is Lead-Lithium (PbLi) eutectic alloy and advanced Reduced Activation Ferritic/Martensitic (RAFM) steel. The research performed here is aimed at: (1) better understanding of corrosion processes in the system including RAFM steel and flowing PbLi in the presence of a strong magnetic field and (2) prediction of corrosion losses in conditions of a Dual Coolant Lead Lithium (DCLL) blanket, which is at present the key liquid metal blanket concept in the US. To do this, numerical and analytical tools have been developed and then applied to the analysis of corrosion processes. First, efforts were taken to develop a computational suite called TRANSMAG (Transport phenomena in Magnetohydrodynamic Flows) as an analysis tool for corrosion processes in the PbLi/RAFM system, including transport of corrosion products in MHD laminar and turbulent flows. The computational approach in TRANSMAG is based on simultaneous solution of flow, energy and mass transfer equations with or without a magnetic field, assuming mass transfer controlled corrosion and uniform dissolution of iron in the flowing PbLi. Then, the new computational tool was used to solve an inverse mass transfer problem where the saturation concentration of iron in PbLi was reconstructed from the experimental data resulting in the following correlation: CS = e 13.604--12975/T, where T is the temperature of PbLi in K and CS is in wppm. The new correlation for saturation concentration was then used in the analysis of corrosion processes in laminar flows in a rectangular duct in the presence of a strong transverse magnetic field. As shown in this study, the mass loss increases with the magnetic field such that the corrosion rate in the presence of a magnetic field can be a few times higher compared to purely

  12. Oxidation kinetics of hydride-bearing uranium metal corrosion products

    NASA Astrophysics Data System (ADS)

    Totemeier, Terry C.; Pahl, Robert G.; Frank, Steven M.

    The oxidation behavior of hydride-bearing uranium metal corrosion products from Zero Power Physics Reactor (ZPPR) fuel plates was studied using thermo-gravimetric analysis (TGA) in environments of Ar-4%O 2, Ar-9%O 2, and Ar-20%O 2. Ignition of corrosion product samples from two moderately corroded plates was observed between 125°C and 150°C in all environments. The rate of oxidation above the ignition temperature was found to be dependent only on the net flow rate of oxygen in the reacting gas. Due to the higher net oxygen flow rate, burning rates increased with increasing oxygen concentration. Oxidation rates below the ignition temperature were much slower and decreased with increasing test time. The hydride contents of the TGA samples from the two moderately corroded plates, determined from the total weight gain achieved during burning, were 47-61 wt% and 29-39 wt%. Samples from a lightly corroded plate were not reactive; X-ray diffraction (XRD) confirmed that they contained little hydride.

  13. Corrosion fatigue of iron-chromium-nickel alloys: Fracture mechanics, microstructure and chemistry. Final technical report, June 1, 1988--November 30, 1993

    SciTech Connect

    Wei, R.P.

    1994-01-05

    A multi-disciplinary research program was undertaken to address certain fundamental issues relating to corrosion fatigue crack growth in structurally important alloys in aqueous solutions. Focus was placed on austenitic iron-chromium-nickel alloys.

  14. Chlorates induce pitting corrosion of iron in sulfuric acid solutions: An analysis based on current oscillations and a point defect model

    NASA Astrophysics Data System (ADS)

    Pagitsas, M.; Pavlidou, M.; Papadopoulou, S.; Sazou, D.

    2007-01-01

    Current oscillatory phenomena were used to investigate the effect of chlorates on the passive state of iron in sulfuric acid solutions. Experimental results show that chlorates cause pitting corrosion, besides general corrosion. It is shown that pitting is not due to the chlorate ion itself, but to chlorides produced via the reduction of chlorates by ferrous ions. General and pitting corrosion are explained in terms of a point defect model proposed to describe the oxide growth and breakdown.

  15. The mutual co-regulation of extracellular polymeric substances and iron ions in biocorrosion of cast iron pipes.

    PubMed

    Jin, Juntao; Guan, Yuntao

    2014-10-01

    New insights into the biocorrosion process may be gained through understanding of the interaction between extracellular polymeric substances (EPS) and iron. Herein, the effect of iron ions on the formation of biofilms and production of EPS was investigated. Additionally, the impact of EPS on the corrosion of cast iron coupons was explored. The results showed that a moderate concentration of iron ions (0.06 mg/L) promoted both biofilm formation and EPS production. The presence of EPS accelerated corrosion during the initial stage, while inhibited corrosion at the later stage. The functional groups of EPS acted as electron shuttles to enable the binding of iron ions. Binding of iron ions with EPS led to anodic dissolution and promoted corrosion, while corrosion was later inhibited through oxygen reduction and availability of phosphorus from EPS. The presence of EPS also led to changes in crystalline phases of corrosion products. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Mass transfer of corrosion products and corrosion of steel in sodium at high hydrogen concentrations

    NASA Astrophysics Data System (ADS)

    Alekseev, V. V.; Kozlov, F. A.; Sorokin, A. P.; Varseev, E. V.; Orlova, E. A.; Torbenkova, I. Yu.

    2015-10-01

    Serviceability of steels in a loop having an increased content of hydrogen is estimated. The equilibrium pressure of hydrogen in a sodium loop saturated with hydrogen is around 10 MPa at a temperature of approximately 630°C and around 100 MPa at 800°C. At the hydrogen pressure equal to 10 MPa, steel with a chromium content of 5% is serviceable to a temperature of 840°C, and steel with a chromium content of 25% is serviceable in the entire considered range of temperatures (above 600°C). At a hydrogen pressure of 80 MPa, steel containing 5% of chromium is not serviceable in the entire considered range of temperatures, and steel containing 25% of chromium is serviceable to a temperature of 830°C. The article presents the results from experimental investigations of the effect of hydrogen on corrosion and mass transfer of corrosion products in a sodium loop at the hydrogen concentration in sodium equal to 6 ppm, which were carried out in the high-temperature section of the sodium test facility (the test facility and the investigation methodology were described in the previous publications of the authors). The distributions of chromium and nickel flows toward the walls over the channel length are obtained at increased hydrogen content (around 6 ppm) and at low oxygen content (less than 2 ppm) in sodium and at a temperature of up to 780°C. For the conditions with relatively low content of oxygen and hydrogen in sodium, the experimental values of chromium flow toward the channel wall are consistent with the calculated data. This fact confirms the possibility of using the previously obtained physicochemical constants for calculating the mass transfer of chromium in high-temperature sodium loops at an increased content of hydrogen in sodium.

  17. Effect of microstructure on the corrosion and deformation behavior of a newly developed 6Mn-5Cr-1.5Cu corrosion-resistant white iron

    NASA Astrophysics Data System (ADS)

    Rao, P. N. V. R. S. S. V. Prasada; Patwardhan, A. K.; Jain, N. C.

    1993-02-01

    An experimental study has been made of the effect of heat treatment on the transformation behavior of a 4.8 pct Cr white iron, alloyed with 6 pct Mn and 1.5 pct Cu, by employing optical metallography, X-ray diffractometry, and differential thermal analysis (DTA) techniques, with a view to assess the suitability of the different microstructures in resisting aqueous corrosion. The matrix microstructure in the as-cast condition, comprising pearlite + bainite/martensite, transformed to austenite on heat-treating at all the temperatures between 900 °C and 1050 °C. Increasing the soaking period at each of the heat-treating temperatures led to an increase in the volume fraction and stability of austenite. M3C was the dominant carbide present in the as-cast condition. On heat-treating, different carbides formed: M23C6 carbide was present on heat-treating at 900 °C and 950 °C; on heat-treating at 1000 °C, M7C3 formed and persisted even on heattreating at 1050 °C. The possible formation of M5C2 carbide in the as-cast and heat-treated conditions (900 °C and 950 °C) is also indicated. Dispersed carbides (DC), present in austenite up to 950 °C, mostly comprised M3C and M5C2. On stress relieving of the heat-treated samples, M7C3-type DC also formed. The hardness changes were found to be consistent with the micro-structural changes occurring on heat-treating. The as-cast state was characterized by a reasonable resistance to corrosion in 5 pct NaCl solution. On heat-treating, the corrosion resistance improved over that in the as-cast state. After 4 hours soaking, increasing the temperature from 900 °C to 1050 °C led to an improvement in corrosion resistance. However, after 10 hours soaking, corrosion resistance decreased on increasing the temperature from 900 °C to 950 °C and improved thereafter on increasing the heat-treating temperature. Deformation behavior responded to the microstructure on similar lines as the corrosion behavior. Although in an early stage of

  18. Mössbauer spectroscopy study of iron corrosion underneath painting system

    NASA Astrophysics Data System (ADS)

    Nigam, R. K.; Hajela, B. P.; Sengupta, S.; Srivastava, B. C.; Gupta, K. M.

    1986-02-01

    The effect of pigments on the development of corrosion products between the painting system and metal surface when exposed to marine environments has been discussed. The pigments studied were; Red Mud Zinc chromate, Zinc chromate, Red oxide Zinc Phosphate, Manganese Phosphate Barium chromate and Basic Lead Silico Chromate. Mossbauer Spectroscopy revealed that the upper rust layer in all the cases consisted of γ-Fe203, γ-FeOOH and α-FeOOH. The lower rust layer immediately in contact with the metal surface consisted of an asymmetrical doublet due to γ-FeOOH.

  19. Iron based photoanodes for solar fuel production.

    PubMed

    Bassi, Prince Saurabh; Gurudayal; Wong, Lydia Helena; Barber, James

    2014-06-28

    In natural photosynthesis, the water splitting reaction of photosystem II is the source of the electrons/reducing equivalents for the reduction of carbon dioxide to carbohydrate while oxygen is formed as the by-product. Similarly, for artificial photosynthesis where the end product is a solar fuel such as hydrogen, a water splitting-oxygen evolving system is required to supply high energy electrons to drive the reductive reactions. Very attractive candidates for this purpose are iron based semiconductors which have band gaps corresponding to visible light and valence band energies sufficient to oxidise water. The most studied system is hematite (Fe2O3) which is highly abundant with many attributes for incorporation into photoelectrochemical (PEC) cells. We review the recent progress in manipulating hematite for this purpose through nanostructuring, doping and surface modifications. We also consider several hybrid iron-based semiconducting systems like ferrites and iron titanates as alternatives to hematite for light driven water splitting emphasizing their advantages with respect to their band levels and charge transport properties.

  20. Exposure testing of fasteners in preservative treated wood : gravimetric corrosion rates and corrosion product analyses

    Treesearch

    Samuel L. Zelinka; Rebecca J. Sichel; Donald S. Stone

    2010-01-01

    Research was conducted to determine the corrosion rates of metals in preservative treated wood and also understand the mechanism of metal corrosion in treated wood. Steel and hot-dip galvanized steel fasteners were embedded in wood treated with one of six preservative treatments and exposed to 27oC at 100% relative humidity for 1 year. The...

  1. Corrosion inhibition of Eleusine aegyptiaca and Croton rottleri leaf extracts on cast iron surface in 1 M HCl medium

    NASA Astrophysics Data System (ADS)

    Rajeswari, Velayutham; Kesavan, Devarayan; Gopiraman, Mayakrishnan; Viswanathamurthi, Periasamy; Poonkuzhali, Kaliyaperumal; Palvannan, Thayumanavan

    2014-09-01

    The adsorption and corrosion inhibition activities of Eleusine aegyptiaca (E. aegyptiaca) and Croton rottleri (C. rottleri) leaf extracts on cast iron corrosion in 1 M hydrochloric acid solution were studied first time by weight loss and electrochemical techniques viz., Tafel polarization and electrochemical impedance spectroscopy. The results obtained from the weight loss and electrochemical methods showed that the inhibition efficiency increased with inhibitor concentrations. It was found that the extracts acted as mixed-type inhibitors. The addition of halide additives (KCl, KBr, and KI) on the inhibition efficiency has also been investigated. The adsorption of the inhibitors on cast iron surface both in the presence and absence of halides follows the Langmuir adsorption isotherm model. The inhibiting nature of the inhibitors was supported by FT-IR, UV-vis, Wide-angle X-ray diffraction and SEM methods.

  2. Investigation of gas production and entrapment in granular iron medium

    NASA Astrophysics Data System (ADS)

    Kamolpornwijit, W.; Liang, L.

    2006-01-01

    A method for measuring gas entrapment in granular iron (Fe 0) was developed and used to estimate the impact of gas production on porosity loss during the treatment of a high NO 3- groundwater (up to ˜10 mM). Over the 400-d study period the trapped gas in laboratory columns was small, with a maximum measured at 1.3% pore volume. Low levels of dissolved H 2(g) were measured (up to 0.07 ± 0.02 M). Free moving gas bubbles were not observed. Thus, porosity loss, which was determined by tracer tests to be 25-30%, is not accounted for by residual gas trapped in the iron. The removal of aqueous species (i.e., NO 3-, Ca, and carbonate alkalinity) indicates that mineral precipitation contributed more significantly to porosity loss than did the trapped gases. Using the stoichiometric reactions between Fe 0 and NO 3-, an average corrosion rate of 1.7 mmol kg - 1 d - 1 was derived for the test granular iron. This rate is 10 times greater than Fe 0 oxidation by H 2O alone, based on H 2 gas production. NO 3- ion rather than H 2O was the major oxidant in the groundwater in the absence of molecular O 2. The N-mass balance [e.g., N 2(g) and NH 4+ and NO 3-] suggests that abiotic reduction of NO 3- dominated at the start of Fe 0 treatment, whereas N 2 production became more important once the microbial activity began. These laboratory results closely predict N 2 gas production in a separated large column experiment that was operated for ˜2 yr in the field, where a maximum of ˜600 ml d - 1 gas volumes was detected, of which 99.5% (v/v) was N 2. We conclude that NO 3- suppressed the production of H 2(g) by competing with water for Fe 0 oxidation, especially at the beginning of water treatment when Fe 0 is highly reactive. Depends on the groundwater composition, gas venting may be necessary in maintaining PRB performance in the field.

  3. Evaluation of iron aluminide weld overlays for erosion - corrosion resistant boiler tube coatings in low NO{sub x} boilers

    SciTech Connect

    DuPont, J.N.; Banovic, S.W.; Marder, A.R.

    1996-08-01

    Low NOx burners are being installed in many fossil fired power plants in order to comply with new Clean Air Regulations. Due to the operating characteristics of these burners, boiler tube sulfidation corrosion is often enhanced and premature tube failures can occur. Failures due to oxidation and solid particle erosion are also a concern. A program was initiated in early 1996 to evaluate the use of iron aluminide weld overlays for erosion/corrosion protection of boiler tubes in Low NOx boilers. Composite iron/aluminum wires will be used with the Gas Metal Arc Welding (GMAW) process to prepare overlays on boiler tubes steels with aluminum contents from 8 to 16wt%. The weldability of the composite wires will be evaluated as a function of chemical composition and welding parameters. The effect of overlay composition on corrosion (oxidation and sulfidation) and solid particle erosion will also be evaluated. The laboratory studies will be complemented by field exposures of both iron aluminide weld overlays and co-extruded tubing under actual boiler conditions.

  4. Characterization of reaction products of iron and iron salts and aqueous plant extracts

    NASA Astrophysics Data System (ADS)

    Jaén, J. A.; García de Saldaña, E.; Hernández, C.

    1999-11-01

    The complexes formed in aqueous solution as a result of a reaction of iron and iron salts (Fe2+ and Fe3+) and some plant extracts were analyzed using Mössbauer spectroscopy and Fourier transform infrared. The extracts were obtained from Opuntia elatior mill., Acanthocereus pentagonus (L.) Britton, Mimosa tenuiflora, Caesalpinia coriaria (Jacq.) Willd., Bumbacopsis quinata (Jacq.) Dugand and Acacia mangium Willd., plants growing wildly in different zones of the Isthmus of Panama. Results suggest the formation of mono- and bis-type complexes, and in some cases, the occurrence of a redox reaction. The feasibility of application of the studied extracts as atmospheric corrosion inhibitors is discussed.

  5. Corrosion Behavior of Copper-Clad Steel Bars with Unclad Two-End Faces for Grounding Grids in the Red Clay Soil

    NASA Astrophysics Data System (ADS)

    Shao, Yupei; Mu, Miaomiao; Zhang, Bing; Nie, Kaibin; Liao, Qiangqiang

    2017-02-01

    Iron-aluminum oxides in the red soil have a significant impact on the corrosion behavior of the metal for grounding grids. Effects of iron-aluminum oxides on the corrosion behavior of the cross section of copper-clad steel in the red soil have been investigated using electrochemical impedance spectroscopy and Tafel polarization. All the data indicate that the iron-aluminum oxides can promote the corrosion of copper-clad steel in the red soil. The corrosivity of the red soil greatly increases after iron-aluminum oxides are added into the soil. Iron-aluminum oxides promote galvanic corrosion of copper-clad steel and increase the corrosion degree of the center steel layer. The iron-aluminum oxides stimulate corrosion process of copper-clad steel acting as a cathodic depolarizing agent. XRD results further validate that the corrosion products of the copper-clad steel bar mainly consist of Fe3O4 and Cu2O.

  6. Application of iron electrode corrosion enhanced electrokinetic-Fenton oxidation to remediate diesel contaminated soils: A laboratory feasibility study

    NASA Astrophysics Data System (ADS)

    Tsai, Tzai-Tang; Sah, Jygau; Kao, Chih-Ming

    2010-01-01

    SummaryDiesel soil contamination on gas stations or refinery plants is a worldwide environmental problem. The main objectives of this study were to (1) evaluate the efficiency of electrokinetic (EK) by using different electrode materials (graphite and iron rods) and electrolytes (tap water, 0.01 M NaCl, and 0.1 M NaCl) on the remediation of diesel contaminated soils, and (2) evaluate the feasibility of total petroleum hydrocarbon-diesel (TPH-D) reducing in soils via EK-Fenton oxidation enhanced by corroded iron electrode. The EK and EK-Fenton experiments were conducted in batch and sand box experiments, respectively. Batch experiments reveal that the most appropriate electrolyte was 0.1 M NaCl when iron electrode was used in the EK system. Sand box experiments indicate that the TPH-D concentration dropped from 10,000 to 300 mg kg -1 when amorphous iron/total iron (Fe o/Fe t) ratio increased from 0.1 to 0.33, with the addition of 8% of H 2O 2 and 0.1 M NaCl after 60 days of EK-Fenton operation. Electrokinetically enhanced oxidation with the presence of both H 2O 2 and Fe 3O 4 (iron electrode corrosion) resulted in higher TPH-D removal efficiency (97%) compared to the efficiencies observed from EK (55%) or Fenton oxidation (27%) alone. This demonstrates that EK-Fenton oxidation catalyzed by iron electrode corrosion is a valuable direction to efficiently and effectively remediate diesel contaminated soils.

  7. 78 FR 59652 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-27

    ... International Trade Administration Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of... administrative review of the antidumping duty order on certain corrosion-resistant carbon steel flat products... Results. \\2\\ See Certain Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea:...

  8. 77 FR 24221 - Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Notice of Commission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-23

    ... COMMISSION Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Notice of Commission... countervailing duty order on corrosion-resistant carbon steel flat products from Korea and the antidumping duty orders on corrosion- resistant carbon steel flat products from Germany and Korea would be likely to...

  9. 77 FR 31877 - Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Scheduling of Full Five...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-30

    ... COMMISSION Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Scheduling of Full Five... duty order on corrosion-resistant carbon steel flat products from Korea and the antidumping duty orders on corrosion- resistant carbon steel flat products from Germany and Korea would be likely to lead...

  10. 77 FR 54891 - Certain Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Preliminary...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-06

    ... International Trade Administration Certain Corrosion-Resistant Carbon Steel Flat Products from the Republic of... administrative review of the antidumping order on corrosion-resistant carbon steel flat products (CORE) from the... the order on March 12, 2012. See Certain Corrosion- Resistant Carbon Steel Flat Products From the...

  11. 78 FR 55057 - Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Preliminary Results of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-09

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea... antidumping duty order on corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea.... See Corrosion-Resistant Carbon Steel Flat Products from Germany and the Republic of Korea: Revocation...

  12. 77 FR 72827 - Corrosion-Resistant Carbon Steel Flat Products From Germany and the Republic of Korea: Final...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-06

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From Germany and the Republic... on certain corrosion- resistant carbon steel flat products (``CORE'') from Germany and the Republic... Reviews'' section of this notice. \\1\\ Corrosion-Resistant Carbon Steel Flat Products From Germany and the...

  13. 75 FR 55769 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-14

    ... International Trade Administration Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of... administrative review of the antidumping order on corrosion-resistant carbon steel flat products (CORE) from the... Antidumping Duty Orders on Certain Cold-Rolled Carbon Steel Flat Products and Certain Corrosion-Resistant...

  14. 76 FR 15291 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-21

    ... International Trade Administration Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of... for certain corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea (Korea). See Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

  15. The Mineralogy of Microbiologically Influenced Corrosion

    DTIC Science & Technology

    2015-01-01

    product linked to the resulting corrosion, e.g., sulfate- and iron-reducing; sulfur -, iron-, and manganese-oxidizing; or acid- and sulfide-producing...layer. However, iron oxides on unalloyed steel in alkaline media (e.g., steel in concrete ) are passive. Similarly, copper forms passivating layers in...concluded that at temperatures below 100 °C, titanium is not vulnerable to iron/ sulfur -oxidizing, SRB, acid-producing bacteria (APB), differential

  16. Influence of pH on the localized corrosion of iron

    SciTech Connect

    Webley, R.; Henry, R.

    1986-06-01

    The influence of pH on the pitting corrosion of iron in chloride and sulfate solutions was determined using two artificial pit apparatuses to obtain the pH near the surface of the pit bottom. A glass membrane electrode and an antimony electrode were used to measure pH in the two apparatuses. Using solutions of NaCl and Na/sub 2/SO/sub 4/ at current densities of 0.5, 5.0, and 10 mA/cm/sup 2/ pH's in the range 5 to 6 were obtained with the first apparatus. The antimony probe did not measure pH accurately in solutions of 1 N NaCl and 1 N Na/sub 2/SO/sub 4/ and had an error of approximately 2 pH units. A one-dimensional transport model was developed to predict pH variations around the pit mouth and inside the pit. The validity of this model was not verified due to the relative lack of precision with pH measurement techniques.

  17. Control of marrow production by the level of iron supply

    PubMed Central

    Hillman, Robert S.; Henderson, Perry A.

    1969-01-01

    The level of erythroid marrow production varies widely in different erythropoietic disorders. In part, this reflects the level of erythropoietin stimulation as determined by the severity of the anemia. However, iron supply plays an equally important role in the control of erythropoiesis. As demonstrated in normal individuals subjected to prolonged periods of phlebotomy-induced anemia, the erythroid marrow will increase production by as little as twice to as much as eight times normal, depending on the iron supply available from different iron pools. Whereas the iron delivered from normal reticuloendothelial stores or orally administered iron is sufficient for a marrow production response of only two to three times normal, the increased iron supply from nonviable red cells, hemolysis, or iron dextran infusions permits marrow production to rise acutely to levels of four to eight times normal. PMID:5773083

  18. Concrete Cracking Prediction Including the Filling Proportion of Strand Corrosion Products

    PubMed Central

    Wang, Lei; Dai, Lizhao; Zhang, Xuhui; Zhang, Jianren

    2016-01-01

    The filling of strand corrosion products during concrete crack propagation is investigated experimentally in the present paper. The effects of stirrups on the filling of corrosion products and concrete cracking are clarified. A prediction model of crack width is developed incorporating the filling proportion of corrosion products and the twisting shape of the strand. Experimental data on cracking angle, crack width, and corrosion loss obtained from accelerated corrosion tests of concrete beams are presented. The proposed model is verified by experimental data. Results show that the filling extent of corrosion products varies with crack propagation. The rust filling extent increases with the propagating crack until a critical width. Beyond the critical width, the rust-filling extent remains stable. Using stirrups can decrease the critical crack width. Stirrups can restrict crack propagation and reduce the rust filling. The tangent of the cracking angle increases with increasing corrosion loss. The prediction of corrosion-induced crack is sensitive to the rust-filling extent. PMID:28772367

  19. The Corrosion Study in the Tubing for Gas Production on the CBM Reservoir including CO2

    NASA Astrophysics Data System (ADS)

    Kim, K. H.; Kang, I. O.; Han, J. M.; Lee, S. M.

    2016-12-01

    In the CBM reservoir, although the gas mainly contains more than 85% CH4, it actually consists of multi-component such as CH4, CO2 and N2. Both the multi-component gas including CO2 and water are produced together from Coalbed into tubing. Because the reaction between CO2 and water always acts as the heart of the corrosion mechanisms, the presence of CO2 can produce several aspects of corrosion problem in the coalbed. In this study, we analyzed the experimental report of the sorption and gas content about the specific CBM field. By the using reservoir simulator, we have calculated about the changing the composition of desorption gas for production period. Applied on the simulation results, we identified corrosion rate of the tubing for applied dewaad corrosion model. Firstly, we conducted sensitivity analysis on the variable ranges of the properties. Secondly, we checked the maximum corrosion rate into the production well. Finally, we measured the cumulative corrosion rate for production duration. Although the CO2 mole fraction existed in coal reaches 20 percents, the amount of CO2 is left into the coal matrix without desorption because CO2 is preferentially adsorbed onto the coal matrix. Thus, the CO2 mole fraction into production well is lowly calculated from 5 to 6 percents. Since the water rate is especially changing for production period in CBM, the water gas ratio which is mainly affected by corrosion rate dramatically varies with the production period. Applied on these results from CBM, the CO2 corrosion rate becomes higher at the higher pressure of a deeper place in general, because the CO2 partial pressure increases. However, as it generated FeCO3 protection above the specific temperature, the corrosion rate is inversely decreased at the deeper tubing section above critical depth. From the sensitivity studies on CBM reservoir including CO2, it was identified that corrosion rate relatively shows the low value as compared with CO2 composition due to the

  20. Iron-stimulated toxin production in Microcystis aeruginosa.

    PubMed Central

    Utkilen, H; Gjølme, N

    1995-01-01

    Nitrate- and phosphate-limited conditions had no effect on toxin production by Microcystis aeruginosa. In contrast, iron-limited conditions influenced toxin production by M. aeruginosa, and iron uptake was light dependent. A model for production of toxin by M. aeruginosa is proposed. PMID:7574617

  1. Chapter 23: Corrosion of Metals in Wood Products

    Treesearch

    Samuel L. Zelinka

    2014-01-01

    The corrosion of metals in contact with wood has been studied for over 80 years, and in most situations wood is not corrosive [1]. Recently, however, the durability of fasteners in preservative--treated wood has become a concern. Changes in legislation and certification in the United States, the European Union, and Australasia have restricted the use of chromated...

  2. Dietary iron intervention using a staple food product for improvement of iron status in female runners.

    PubMed

    Alaunyte, Ieva; Stojceska, Valentina; Plunkett, Andrew; Derbyshire, Emma

    2014-01-01

    Adequate nutrient intake is critically important for achieving optimal sports performance. Like all athletes, female runners require a nutritionally balanced diet to maintain daily activities and a successful training regime. This study investigates the effects of cereal product based dietary iron intervention on iron status of recreational female runners (n = 11; 32 ± 7yr; 239 ± 153 minutes exercise/week, of which 161 ± 150 minutes running activity/week; VO2max 38 ± 4 ml/kg/min). Participants completed a 6-week dietary intervention study. They were asked to replace their usual bread with iron-rich Teff bread as part of their daily diet. During this period, their dietary habits were assessed by multiple pass 24-hr recalls; iron status was determined by venous blood analysis for serum transferrin, serum transferrin receptor, serum ferritin, total iron-binding capacity and transferrin receptor/ferritin log index. Pre-intervention a cohort of 11 female runners reported inadequate daily dietary iron intake of 10.7 ± 2.7 mg/day, which was associated with overall compromised iron status. Over a third of all participants showed depleted bodily iron stores (serum ferritin <12 μg/L). Pre-intervention macronutrient assessment revealed adequate energy, protein and fibre intakes, whilst total fat and saturated fat intake was above the recommendations at the expense of carbohydrate intake. A 6-week dietary intervention resulted in significantly higher total iron intakes (18.5 mg/day, P < 0.05) and improved iron tissue supply but not enlarged iron stores. Improvements in heamatological indices were associated with compromised baseline iron status, prolonged intervention period and increase in dietary iron intake. Dietary iron interventions using a staple cereal product offer an alternative way of improving dietary iron intake and favourable affecting overall iron status in physically active females.

  3. 78 FR 16247 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea; Final Results of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-14

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... antidumping duty order on corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea... section entitled ``Final Results of Review.'' \\1\\ See Certain Corrosion-Resistant Carbon Steel...

  4. 76 FR 69703 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of Extension of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-09

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...) published a notice of initiation of the administrative review of the antidumping duty order on corrosion... results of this review. See Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic...

  5. 76 FR 77775 - Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-14

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea... countervailing duty order on corrosion-resistant carbon steel flat products from the Republic of Korea covering the period January 1, 2009, through December 31, 2009. See Corrosion-Resistant Carbon Steel...

  6. 75 FR 77615 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of Extension of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-13

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...) published a notice of initiation of the administrative review of the antidumping duty order on corrosion... results of this review. See Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic...

  7. 77 FR 13093 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Final Results of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-05

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... administrative review of the countervailing duty (``CVD'') order on corrosion-resistant carbon steel flat... Review'' below. \\1\\ See Corrosion-Resistant Carbon Steel Flat Products from the Republic of...

  8. 78 FR 59651 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-27

    ... International Trade Administration Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of... fourteenth administrative review of the antidumping duty order on certain corrosion-resistant carbon steel... aspects of the Final Results. \\2\\ See Certain Corrosion-Resistant Carbon Steel Flat Products from...

  9. 78 FR 16832 - Corrosion-Resistant Carbon Steel Flat Products From Germany and the Republic of Korea: Revocation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-19

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From Germany and the Republic... corrosion-resistant carbon steel flat products (``CORE'') from Germany and the Republic of Korea (``Korea...-Year (``Sunset'') Review, 77 FR 85 (January 3, 2012). \\2\\ See Corrosion-Resistant Carbon Steel...

  10. 78 FR 19210 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Final Results of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-29

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...) has completed its administrative review of the countervailing duty (CVD) order on corrosion-resistant...\\ See Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Preliminary Results...

  11. 77 FR 14501 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-12

    ... International Trade Administration Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of... antidumping duty administrative review for certain corrosion-resistant carbon steel flat products (CORE) from... (POR) is August 1, 2009, through, July 31, 2010. \\1\\ See Certain Corrosion-Resistant Carbon Steel Flat...

  12. The corrosion product of Cs-Te corrosive compound with 11Cr-Ferritic/Martensitic Steel and 9Cr-Oxide Dispersion Strengthened steel

    NASA Astrophysics Data System (ADS)

    Sasaki, K.; Tanigaki, T.; Fujimura, R.; Fukumoto, K.; Uno, M.

    2015-05-01

    Cs-Te corrosion tests were performed to FBR fuel cladding candidate materials listed below: 11Cr-Ferritic/Martensitic Steel (F/M steel) and 9Cr Oxide Dispersion Strengthened steel (ODS steel). The corrosion products of Cs-Te corrosive compound Cs2Te3 with F/M steel or ODS steel were picked up from the specimens after the corrosion test by focus ion beam method (FIB) and the corrosion products were specified based on element analysis and crystal analysis by transmit electron microscopy (TEM) with electron dispersion X-ray spectrum (EDS). The result of analysis allowed us to presume Cs-Te corrosion reactions in the Fe-Cr based fuel cladding material. The presumable reactions are 4Te + 3/23 Cr23C6 →Cr3Te4 + 18/23 C and 4Te + 3Cr →Cr3Te4 .

  13. Application of stripping voltammetry and microelectrodes in vitro biocompatibility and in vivo toxicity tests of AISI 316L corrosion products.

    PubMed

    Morais, S; Pereira, M C

    2000-04-01

    Adsorptive stripping voltammetric procedures, using mercury film microelectrodes, were optimised and applied to quantify total iron, chromium and nickel in samples of osteoblast-like cells culture medium and mice organs (liver, kidney and spleen) obtained from, respectively, in vitro and in vivo 316L stainless steel corrosion products biocompatibility and toxicity studies. The methods were based on the pre-concentration of the iron-catechol complex by adsorption at the potential of -1.80 V (vs. Ag/AgCl), of the chromium-diethylenetriaminepentaacetic acid complex at -1.00 V or -1.15 V (vs. Ag/AgCl) and of the nickel-dimethylglyoxime complex at -0.70 V (vs. Ag/AgCl). The detection limits achieved for each metal ion (i) in the culture medium were 1.93x10(-8) mol/L Fe, 2.80x10(-10) mol/L Cr and 7.70x10(-9) mol/L Ni for a collection time of 30 s, 40 s and 10 s, respectively, and (ii) in the mice organ solutions were 1.37x10(-8) mol/L Fe, 1.54x10(-8) mol/L Cr and 1.58x10(-9) mol/L Ni for an adsorption time of 25 s, 25 s and 15 s, respectively. The accuracy of the proposed procedures was verified by comparison of the results obtained by adsorptive stripping voltammetry with those attained by atomic absorption spectrometry for the same set of samples and good agreement was found. The in vitro study showed that stainless steel corrosion products affect the expression of the osteogenic phenotype. The in vivo mice model, used to investigate the systemic effects provoked by the corrosion products per se, indicated that Fe, Cr and Ni are partially accumulated in the organs studied and that Ni induced the more significant morphological alterations.

  14. Bioaccumulation and food chain transfer of corrosion products from radioactive stainless steel

    SciTech Connect

    Young, J.S.

    1986-07-01

    Two sets of experiments were conducted to determine if corrosion products from radioactive Type 347 stainless steel could be biologically transferred from sediment through a marine food chain, and whether corrosion products dissolved in seawater could be bioaccumulated and then eliminated. Corrosion products containing /sup 60/Co and /sup 63/Ni from the radioactive stainless steel were introduced into marine sediments. Infaunal polychaete worms exposed to these sediments bioaccumulated the radionuclides. The feeding of these worms to shrimp and fish resulted in a trophic transfer of the radioactive products across a one-step food chain. The magnitude of the transfers are described in terms of transfer factors. Dissolved corrosion products as measured by the radionuclides were also bioaccumulated by shrimp and fish concentrating more than fish. Concentration factors were calculated.

  15. A Fenton-like oxidation process using corrosion of iron metal sheet surfaces in the presence of hydrogen peroxide: a batch process study using model pollutants.

    PubMed

    Namkung, K C; Burgess, A E; Bremner, D H

    2005-03-01

    This study evaluates a new method for chemically destroying organic pollutants in wastewater using spontaneous corrosion of iron metal sheet surfaces in the presence of hydrogen peroxide. Model pollutants (phenol and benzoic acid) were degraded in batch experiments to investigate which parameters affected the process performance. Iron metal sheet surfaces spontaneously corrode under acidic conditions producing iron species (mainly ferrous ions) dissolved in aqueous solution, which react with hydrogen peroxide via the Fenton reaction. In order to optimise the oxidation system, several factors (pH, H2O2 dosage, initial concentration of organic substances) affecting corrosion of the iron metal sheet surface were investigated. Total iron concentration in solution was investigated with different dosages of H2O2 (100 mg l(-1), 1000 mg l(-1) and 1900 mg l(-1)) at different pH values (1.5, 2.5 and 3.0). Iron corrosion increased with the decrease of pH. The addition of H2O2 resulted in a significant increase of iron corrosion. Organic substances also had a marked effect with, for instance, the presence of phenol or benzoic acid resulting in a considerable increase of iron corrosion. In contrast, the absence of either hydrogen peroxide or iron metal brought no change in total organic carbon (TOC). In order to obtain the most effective combination of parameters for TOC removal of phenol solution, experiments were conducted under varied conditions. The experimental results showed that there is an optimum pH requirement (in this work, 2.5). The factors affecting the TOC removal are discussed and the oxidation mechanisms leading to mineralization of organic substances are proposed.

  16. Mössbauer study of corrosion products formed on Fe80B20 and Fe40Ni40(MoB)20 amorphous alloys in an SO2-polluted atmosphere

    NASA Astrophysics Data System (ADS)

    Dávalos, J.; Marco, J. F.; Gracia, M.; Gancedo, J. R.; Greneche, J. M.

    1990-07-01

    ICEMS, XPS, XRD, and AES have been used to study the corrosion layers formed on two metallic glasses, Fe80B20 and Fe40Ni40(MoB)20 (2605 and 2826 MB, Allied Company), exposed to an SO2-polluted humid atmosphere. The iron-containing corrosion products are the same found for pure iron in the same environment, but different relative concentrations were clearly evidenced by ICEMS results. Elemental sulphur, Ni(OH)2, and B(OH)3, the latter enriched at the surface, were found by XPS, XRD, and AES.

  17. Environment-induced embrittlement: Stress corrosion cracking and metal-induced embrittlement; Environmental embrittlement of iron aluminide alloys

    SciTech Connect

    Heldt, L.A.; Milligan, W.W.; White, C.L.

    1991-01-01

    This research program has included two thrusts. The first addressed environment-induced embrittlement in a parallel study of stress corrosion cracking and metal-induced embrittlement. This work has examined (1) mechanical properties as influenced by embrittling environments, (2) fractography and crystallography or transgranular cracking, (3) the mechanics of cracking, (4) the extent and role of local plastic flow, and (5) local chemistry within stress corrosion and metal-induced cracks. The embrittlement of iron aluminide alloys by air was addressed by determining the effect of water and hydrogen upon the mechanical properties. Slow strain rate testing in aqueous environments was carried out at controlled anodic and cathodic potentials. The effect of cathodically charged hydrogen and the effect of subsequent baking were measured. Environmental susceptibility was measured as affected by alloy composition, microstructure and degree of ordering.

  18. Method for forming a layer of synthetic corrosion products on tubing surfaces

    DOEpatents

    Lane, Michael H.; Salamon, Eugene J. M.

    1996-01-01

    A method is provided for forming a synthetic corrosion product layer on tube surfaces. The method utilizes two dissimilar materials with different coefficients of thermal expansion. An object tube and sacrificial tube are positioned one inside the other such that an annular region is created between the two tubes' surfaces. A slurry of synthetic corrosion products is injected into this annular region and the assembly is heat treated. This heat causes the tubes to expand, the inner tube with the higher coefficient of expansion expanding more than the outer tube, thereby creating internal pressures which consolidate the corrosion products and adhere the corrosion products to the tubing surfaces. The sacrificial tube may then be removed by conventional chemical etching or mechanical methods.

  19. Iron nutrition, biomass production, and plant product quality.

    PubMed

    Briat, Jean-François; Dubos, Christian; Gaymard, Frédéric

    2015-01-01

    One of the grand challenges in modern agriculture is increasing biomass production, while improving plant product quality, in a sustainable way. Of the minerals, iron (Fe) plays a major role in this process because it is essential both for plant productivity and for the quality of their products. Fe homeostasis is an important determinant of photosynthetic efficiency in algae and higher plants, and we review here the impact of Fe limitation or excess on the structure and function of the photosynthetic apparatus. We also discuss the agronomic, plant breeding, and transgenic approaches that are used to remediate Fe deficiency of plants on calcareous soils, and suggest ways to increase the Fe content and bioavailability of the edible parts of crops to improve human diet.

  20. Bench-scale evaluation of ferrous iron oxidation kinetics in drinking water: effect of corrosion control and dissolved organic matter.

    PubMed

    Rahman, Safiur; Gagnon, Graham A

    2014-01-01

    Corrosion control strategies are important for many utilities in maintaining water quality from the water treatment plant to the customers' tap. In drinking water with low alkalinity, water quality can become significantly degraded in iron-based pipes if water utilities are not diligent in maintaining proper corrosion control. This article reports on experiments conducted in bicarbonate buffered (5 mg-C/L) synthetic water to determine the effects of corrosion control (pH and phosphate) and dissolved organic matter (DOM) on the rate constants of the Fe(II) oxidation process. A factorial design approach elucidated that pH (P = 0.007, contribution: 42.5%) and phosphate (P = 0.025, contribution: 22.7%) were the statistically significant factors in the Fe(II) oxidation process at a 95% confidence level. The comprehensive study revealed a significant dependency relationship between the Fe(II) oxidation rate constants (k) and phosphate-to- Fe(II) mole ratio. At pH 6.5, the optimum mole ratio was found to be 0.3 to reduce the k values. Conversely, the k values were observed to increase for the phosphate-to- Fe(II) mole ratio > 1. The factorial design approach revealed that chlorine and DOM for the designated dosages did not cause a statistically significant (α = 0.05, P > 0.05)change in rate constants. However, an increment of the chlorine to ferrous iron mole ratio by a factor of ∼ 2.5 resulted in an increase k values by a factor of ∼ 10. This study conclusively demonstrated that the lowest Fe(II) oxidation rate constant was obtained under low pH conditions (pH ≤ 6.5), with chlorine doses less than 2.2 mg/L and with a phosphate-to-Fe(II) mole ratio ≈ 0.3 in the iron water systems.

  1. Effect of molybdenum plus chromium on the corrosion of iron-, nickel-, and cobalt-base alloys in basaltic lava and simulated magmatic gas at 1150/sup 0/C

    SciTech Connect

    Ehrlich, S.A.; Douglass, D.L.

    1982-06-01

    The compatibility of several binary and ternary alloys in a magma environment was studied. Binary alloys containing molybdenum and ternary alloys containing chromium and molybdenum were exposed to basaltic lava at 1150/sup 0/C for periods of 24 and 96 hours. A cover gas was used to produce oxygen and sulfur fugacities corresponding to those of the gases dissolved in basaltic melts. Three base metals were used. These included iron, nickel, and cobalt. The primary reactions in binary alloys were found to be sulfidation. Oxide scales with a spinel layer formed on ternary alloys. The synergistic effect of molybdenum and chromium additions in ternary alloys exhibited superior corrosion resistance to binary alloys which formed base-metal sulfides down grain-boundaries. Extensive analyses of the reaction products by scanning electron microscopy, X-ray energy dispersive analysis, electron microprobe analysis, and metallography are presented for each alloys. The products formed are discussed with reference to thermodynamic stability diagrams, and the reaction path concept is used to explain some of the corrosion.

  2. Methanogens rapidly transition from methane production to iron reduction.

    PubMed

    Sivan, O; Shusta, S S; Valentine, D L

    2016-03-01

    Methanogenesis, the microbial methane (CH4 ) production, is traditionally thought to anchor the mineralization of organic matter as the ultimate respiratory process in deep sediments, despite the presence of oxidized mineral phases, such as iron oxides. This process is carried out by archaea that have also been shown to be capable of reducing iron in high levels of electron donors such as hydrogen. The current pure culture study demonstrates that methanogenic archaea (Methanosarcina barkeri) rapidly switch from methanogenesis to iron-oxide reduction close to natural conditions, with nitrogen atmosphere, even when faced with substrate limitations. Intensive, biotic iron reduction was observed following the addition of poorly crystalline ferrihydrite and complex organic matter and was accompanied by inhibition of methane production. The reaction rate of this process was of the first order and was dependent only on the initial iron concentrations. Ferrous iron production did not accelerate significantly with the addition of 9,10-anthraquinone-2,6-disulfonate (AQDS) but increased by 11-28% with the addition of phenazine-1-carboxylate (PCA), suggesting the possible role of methanophenazines in the electron transport. The coupling between ferrous iron and methane production has important global implications. The rapid transition from methanogenesis to reduction of iron-oxides close to the natural conditions in sediments may help to explain the globally-distributed phenomena of increasing ferrous concentrations below the traditional iron reduction zone in the deep 'methanogenic' sediment horizon, with implications for metabolic networking in these subsurface ecosystems and in past geological settings.

  3. Excellent anti-corrosive pretreatment layer on iron substrate based on three-dimensional porous phytic acid/silane hybrid

    NASA Astrophysics Data System (ADS)

    Gao, Xiang; Lu, Ke; Xu, Lei; Xu, Hua; Lu, Haifeng; Gao, Feng; Hou, Shifeng; Ma, Houyi

    2016-01-01

    A novel, highly effective and environmentally friendly film-forming material, phytic acid (PA)/silane (denoted as PAS) hybrid with a three-dimensional (3D) network structure, was prepared through a condensation reaction of PA with methyltrihydroxysilane generated from the hydrolysis of methyltriethoxysilane (MTES). Two kinds of PAS-based pretreatment layers, namely NaBrO3-free and NaBrO3-doped PAS layers, were fabricated on iron substrates using the dip-coating method. SEM and AFM observations showed that the as-fabricated PAS-based layers possessed a 3D porous microstructure at the nanoscale and a rough surface morphology. X-ray photoelectron spectroscopic (XPS) and attenuated total reflection infrared (ATR-IR) spectroscopic characterization demonstrated that the above PAS layers bound to the iron surface via the -P-O- bond. Moreover, analyses of steady-state polarization curves and electrochemical impedance spectroscopic (EIS) data indicated that the corrosion rates of the iron substrates decreased considerably in the presence of the two PAS-based pretreatment layers. In particular, the NaBrO3-dosed PAS layer displayed the better corrosion resistance ability as well as maintaining the original microstructure and surface morphology. The PAS-based pretreatment layers are expected to act as substitutes for chromate and phosphate conversion layers and will find widespread application in the surface pretreatment of iron and steel materials due to the advantages of being environmentally friendly, the rapid film-forming process, and, especially, the nanoporous microstructure and rough surface morphology.A novel, highly effective and environmentally friendly film-forming material, phytic acid (PA)/silane (denoted as PAS) hybrid with a three-dimensional (3D) network structure, was prepared through a condensation reaction of PA with methyltrihydroxysilane generated from the hydrolysis of methyltriethoxysilane (MTES). Two kinds of PAS-based pretreatment layers, namely Na

  4. Contact corrosion measurements on the pair UO 2+ x and carbon steel 1.0330 in brines and bentonite porewater with respect to direct waste disposal

    NASA Astrophysics Data System (ADS)

    Engelhardt, J.; Marx, G.

    1999-01-01

    Contact corrosion between carbon steel and UO 2 was studied in the MgCl 2 rich Q-brine, in bentonite porewater and in saturated NaCl solution by use of contact potential and contact current measurements. In all solutions the carbon steel dominates the contact potential, so that this potential is near to the rest potential of the carbon steel. Only in solutions without precipitation of iron corrosion products, the presence of metallic iron slightly reduces the UO 2 corrosion rate. If iron corrosion products precipitate, the relevant adsorption of the uranium species will be more effective than any direct cathodic corrosion protection.

  5. LITERATURE REVIEW ON THE SORPTION OF PLUTONIUM, URANIUM, NEPTUNIUM, AMERICIUM AND TECHNETIUM TO CORROSION PRODUCTS ON WASTE TANK LINERS

    SciTech Connect

    Li, D.; Kaplan, D.

    2012-02-29

    The Savannah River Site (SRS) has conducted performance assessment (PA) calculations to determine the risk associated with closing liquid waste tanks. The PA estimates the risk associated with a number of scenarios, making various assumptions. Throughout all of these scenarios, it is assumed that the carbon-steel tank liners holding the liquid waste do not sorb the radionuclides. Tank liners have been shown to form corrosion products, such as Fe-oxyhydroxides (Wiersma and Subramanian 2002). Many corrosion products, including Fe-oxyhydroxides, at the high pH values of tank effluent, take on a very strong negative charge. Given that many radionuclides may have net positive charges, either as free ions or complexed species, it is expected that many radionuclides will sorb to corrosion products associated with tank liners. The objective of this report was to conduct a literature review to investigate whether Pu, U, Np, Am and Tc would sorb to corrosion products on tank liners after they were filled with reducing grout (cementitious material containing slag to promote reducing conditions). The approach was to evaluate radionuclides sorption literature with iron oxyhydroxide phases, such as hematite ({alpha}-Fe{sub 2}O{sub 3}), magnetite (Fe{sub 3}O{sub 4}), goethite ({alpha}-FeOOH) and ferrihydrite (Fe{sub 2}O{sub 3} {center_dot} 0.5H{sub 2}O). The primary interest was the sorption behavior under tank closure conditions where the tanks will be filled with reducing cementitious materials. Because there were no laboratory studies conducted using site specific experimental conditions, (e.g., high pH and HLW tank aqueous and solid phase chemical conditions), it was necessary to extend the literature review to lower pH studies and noncementitious conditions. Consequently, this report relied on existing lower pH trends, existing geochemical modeling, and experimental spectroscopic evidence conducted at lower pH levels. The scope did not include evaluating the appropriateness

  6. IRON COATED URANIUM AND ITS PRODUCTION

    DOEpatents

    Gray, A.G.

    1960-03-15

    A method of applying a protective coating to a metallic uranium article is given. The method comprises etching the surface of the article with an etchant solution containlng chloride ions, such as a solution of phosphoric acid and hydrochloric acid, cleaning the etched surface, electroplating iron thereon from a ferrous ammonium sulfate electroplating bath, and soldering an aluminum sheath to the resultant iron layer.

  7. Production of iron from metallurgical waste

    SciTech Connect

    Hendrickson, David W; Iwasaki, Iwao

    2013-09-17

    A method of recovering metallic iron from iron-bearing metallurgical waste in steelmaking comprising steps of providing an iron-bearing metallurgical waste containing more than 55% by weight FeO and FeO equivalent and a particle size of at least 80% less than 10 mesh, mixing the iron-bearing metallurgical waste with a carbonaceous material to form a reducible mixture where the carbonaceous material is between 80 and 110% of the stoichiometric amount needed to reduce the iron-bearing waste to metallic iron, and as needed additions to provide a silica content between 0.8 and 8% by weight and a ratio of CaO/SiO.sub.2 between 1.4 and 1.8, forming agglomerates of the reducible mixture over a hearth material layer to protect the hearth, heating the agglomerates to a higher temperature above the melting point of iron to form nodules of metallic iron and slag material from the agglomerates by melting.

  8. Interleukin 2 production in iron-deficient children.

    PubMed

    Galan, P; Thibault, H; Preziosi, P; Hercberg, S

    1992-01-01

    The relationship between iron status and capacity for IL-2 production by lymphocytes was assessed in 81 children from 6 mo to 3 yr of age selected at random from a population with low socioeconomic status, undergoing free systematic examination in four children's health centers in the Paris area. Iron deficiency was defined by the existence of at least two abnormal values among the three indicators of iron status: serum ferritin level less than or equal to 12 micrograms/L, transferrin saturation less than 12%, and erythrocyte protoporphyrin concentration greater than 3 micrograms/g hemoglobin. According to this definition, 53 children were classified as iron deficient and 28 as iron sufficient. No differences were observed between the iron-deficient and iron-sufficient groups in terms of the IL-2 concentration without stimulation by PHA. IL-2 production by lymphocytes stimulated with PHA, as well as the stimulation index (ratio of IL-2 concentration following stimulation by PHA to that of IL-2 concentration without stimulation by PHA) were significantly lower in iron-deficient children. The reduction in IL-2 production by activated lymphocytes observed in our study of iron-deficient children may be responsible for impairments in immunity found by other authors, particularly in cell-mediated immunity.

  9. Cogeneration process for production of energy and iron materials

    SciTech Connect

    Lehto, J.M.

    1991-10-08

    This paper reports a process for the production of electricity. It comprises: providing a low grade coal fuel' performing a pyrolysis procedure on the coal fuel at a temperature of about 600{degrees} C. to remove oil and volatiles therefrom, and to generate a resultant coal char product; pelletizing the coal char product to form coal char product pellets, the step of pelletizing comprising pelletizing at least a portion of the coal char product in combination with reducible solid iron material to form coal char pellets containing reducible solid iron material; charging a cupola with the coal char product and the reducible solid iron material, the step of charging a cupola being characterized by charging substantially all the coal char product in the form of coal char product pellets and substantially all the reducible solid iron material in the form of pellets containing the coal char product in combination with the reducible solid iron material; reducing and melting all the reducible solid iron material in the coal char pellets by heating the pellets in the cupola at a suitable temperature under a pressure of at least about 100 psi in the presence of a sufficient upward flow of process gases, with the resultant formation of hot product gases.

  10. GEOCHEMISTRY OF SULFUR IN IRON CORROSION SCALES FOUND IN DRINKING WATER DISTRIBUTION SYSTEMS

    EPA Science Inventory

    Iron-sulfur geochemistry is important in many natural and engineered environments, including drinking water systems. In the anaerobic environment beneath scales of corroding iron drinking water distribution system pipes, sulfate reducing bacteria (SRB) produce sulfide from natu...

  11. Role of orthophosphate as a corrosion inhibitor in chloraminated solutions containing tetravalent lead corrosion product PbO2.

    PubMed

    Ng, Ding-Quan; Strathmann, Timothy J; Lin, Yi-Pin

    2012-10-16

    Addition of orthophosphate has been commonly employed to suppress lead levels in drinking water. Its detailed mechanism and time required for it to become effective, however, have not been fully elucidated. In this study, we investigated the mechanistic role of orthophosphate as a corrosion inhibitor in controlling lead release from tetravalent lead corrosion product PbO(2) in chloraminated solutions, a system representing distribution networks experiencing disinfectant changeover from free chlorine to monochloramine. In all experiments with orthophosphate addition of at least 1 mg/L as P, peaking of soluble Pb(II) concentration within the first 24 h was observed before lead concentrations decreased and stabilized at levels lower than 15 μg/L. The variation of soluble Pb(II) concentration could be attributed to the dynamics between the rate of PbO(2) reductive dissolution, primarily induced by monochloramine decomposition, and that of chloropyromorphite (Pb(5)(PO(4))(3)Cl) precipitation, which did not occur until a critical supersaturation ratio of about 2.36 was reached in the solution. Our findings provide insights to how orthophosphate reduces lead levels under drinking water conditions and highlight the potential risk of short-term elevated lead concentrations. Intensive monitoring following the disinfectant changeover may be required to determine the overall lead exposure when using orthophosphate as a corrosion inhibitor.

  12. Spontaneous activation of CO2 and corrosion pathways on iron surface Fe(100): a quantum mechanical study informed by DFT-based dynamics

    NASA Astrophysics Data System (ADS)

    Glezakou, V. A.; McGrail, P.; Dang, L. X.

    2009-12-01

    Because of the rapidly increasing interest in technologies for capturing and permanently sequestering CO2 as part of a climate change mitigation strategy, understanding the interaction of CO2 with materials that comprise a sequestration system (steels, cements, silicate minerals, etc.) is of fundamental importance. The majority of models for corrosion of metals involve water-mediated processes, with CO2 dissolved in the aqueous phase playing a minor role in the process. In contrast, recent experiments with mild steels have shown that much greater corrosivity actually occurs in the dense CO2 phase, provided sufficient molecular water is present in the CO2 phase to catalyse certain reactions. In our study, we use DFT-based dynamics to study the internal structure of the the super-critical CO2/(H2O)n system, with n=0-4. While water does not disturb the super-critical CO2 phase, it also gives rise to short-lived CO2...H2O bonds which are likely to facilitate the activation of CO2 on the surface, but otherwise maintains its molecular form. We also use DFT methods to probe the fundamental interactions of CO2 or SO2 and H2O with clean or doped iron surfaces and determine the reactive pathways that lead to CO2 chemisorption, dissociation and further formation of corrosion products in the form of carbonates or sulfites. DFT-based molecular dynamics are employed to sample the configurational space of reactants and products more efficiently. CO2 adsorbs readily on the surface assuming a bent geometry, indicative of charge transfer from the surface to CO2, which closely resembles a CO2- moiety. Once CO2 is adsorbed, it can decompose to adsorbed O+CO, which further reacts with CO2 or SO2 to form corrosion products. Molecularly adsorbed water acts as catalyst to lower these reaction barriers. Clearly, the reactive pathways on the surface are quite different than those in aqueous solution. Battelle operates Pacific Northwest National Laboratory for the US Department of Energy.

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

    PubMed

    Sherif, El-Sayed M

    2014-07-09

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

  14. Effect of traditional oriental soy products on iron absorption.

    PubMed

    Macfarlane, B J; van der Riet, W B; Bothwell, T H; Baynes, R D; Siegenberg, D; Schmidt, U; Tal, A; Taylor, J R; Mayet, F

    1990-05-01

    The effect of a variety of traditional oriental unfermented and fermented soy products on iron absorption was evaluated in 242 Indian women. When compared with a soy-flour meal containing an equal amount of protein, iron absorption was found to be significantly improved with silken tofu, natto, tempeh, rice miso, barley miso, and soybean miso. This improvement could not be adequately explained except with reference to changes in the protein composition of the products. The protein fraction profiles of the soy products were obtained by size-exclusion high-performance liquid chromatography. An inverse relationship between food iron absorption and the high-molecular-weight fraction of the soy products was demonstrated (r = 0.66, p = 0.01). However, anomalous results obtained with three products (sufu, tempeh, and fully hydrolyzed isolated soy protein) did not make it possible to reach firm conclusions concerning the effect of the protein fraction of soy on iron bioavailability.

  15. FY05 HPCRM Annual Report: High-Performance Corrosion-Resistant Iron-Based Amorphous Metal Coatings

    SciTech Connect

    Farmer, J; Choi, J; Haslam, J; Day, S; Yang, N; Headley, T; Lucadamo, G; Yio, J; Chames, J; Gardea, A; Clift, M; Blue, G; Peters, W; Rivard, J; Harper, D; Swank, D; Bayles, R; Lemieux, E; Brown, R; Wolejsza, T; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Lavernia, E; Schoenung, J; Ajdelsztajn, L; Dannenberg, J; Graeve, O; Lewandowski, J; Perepezko, J; Hildal, K; Kaufman, L; Boudreau, J

    2007-09-20

    New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Two Fe-based amorphous metal formulations have been found that appear to have corrosion resistance comparable to, or better than that of Ni-based Alloy C-22, based on breakdown potential and corrosion rate. Both Cr and Mo provide corrosion resistance, B enables glass formation, and Y lowers critical cooling rate (CCR). SAM1651 has yttrium added, and has a nominal critical cooling rate of only 80 Kelvin per second, while SAM2X7 (similar to SAM2X5) has no yttrium, and a relatively high critical cooling rate of 610 Kelvin per second. Both amorphous metal formulations have strengths and weaknesses. SAM1651 (yttrium added) has a low critical cooling rate (CCR), which enables it to be rendered as a completely amorphous thermal spray coating. Unfortunately, it is relatively difficult to atomize, with powders being irregular in shape. This causes the powder to be difficult to pneumatically convey during thermal spray deposition. Gas atomized SAM1651 powder has required cryogenic milling to eliminate irregularities that make flow difficult. SAM2X5 (no yttrium) has a high critical cooling rate, which has caused problems associated with devitrification. SAM2X5 can be gas atomized to produce spherical powders of SAM2X5, which enable more facile thermal spray deposition. The reference material, nickel-based Alloy C-22, is an outstanding corrosion-resistant engineering material. Even so, crevice corrosion has been observed with C-22 in hot sodium chloride environments without buffer

  16. Characterization of corrosion products from atmospheric exposures for up to 5 years

    SciTech Connect

    Hernandez, L.S.; Miranda, J.M.; Narvaez, L.; Garcia, G.

    1998-12-31

    Four metallic materials of economic significance were exposed to an urban atmosphere up to five years. These materials were low carbon steel, zinc (as galvanized steel), copper and aluminum all of commercial quality. The corrosion rate was measured after 1, 2, 3 and 5 years using a weight loss method. Sulfur dioxide deposition rate and climatological parameters were determined monthly. At the same time, different techniques were used to characterize the corrosion products developed on the above materials. Results obtained by polarization resistance technique (Rp) in a 0.1 M Na{sub 2}SO{sub 4} solution revealed that, the longer the exposure time, the greater the corrosion products protection, as result of broadening and compactness of such products, this was verified by scanning electron microscopy (SEM). Through x-rays diffraction (XRD), the expected crystalline compounds on steel and copper were identified and also, the transformation of middling protective initial products into other more protective was followed. For aluminum and zinc it was not possible to identify the crystalline compounds perhaps due to the very thin corrosion products layers. So, these materials were analyzed by means of Raman spectroscopy. a-Al{sub 2}O, was identified on an aluminum sample whereas on zinc any corrosion product could not be identified due to excessive fluorescence.

  17. Corrosion of aluminides by molten nitrate salt

    SciTech Connect

    Tortorelli, P.F.; Bishop, P.S.

    1990-01-01

    The corrosion of titanium-, iron-, and nickel-based aluminides by a highly aggressive, oxidizing NaNO{sub 3}(-KNO{sub 3})-Na{sub 2}O{sub 2} has been studied at 650{degree}C. It was shown that weight changes could be used to effectively evaluate corrosion behavior in the subject nitrate salt environments provided these data were combined with salt analyses and microstructural examinations. The studies indicated that the corrosion of relatively resistant aluminides by these nitrate salts proceeded by oxidation and a slow release from an aluminum-rich product layer into the salt at rates lower than that associated with many other types of metallic materials. The overall corrosion process and resulting rate depended on the particular aluminide being exposed. In order to minimize corrosion of nickel or iron aluminides, it was necessary to have aluminum concentrations in excess of 30 at. %. However, even at a concentration of 50 at. % Al, the corrosion resistance of TiAl was inferior to that of Ni{sub 3}Al and Fe{sub 3}Al. At higher aluminum concentrations, iron, nickel, and iron-nickel aluminides exhibited quite similar weight changes, indicative of the principal role of aluminum in controlling the corrosion process in NaNO{sub 3}(-KNO{sub 3})-Na{sub 2}O{sub 2} salts. 20 refs., 5 figs., 3 tabs.

  18. Products of in Situ Corrosion of Depleted Uranium Ammunition in Bosnia and Herzegovina Soils.

    PubMed

    Wang, Yuheng; von Gunten, Konstantin; Bartova, Barbora; Meisser, Nicolas; Astner, Markus; Burger, Mario; Bernier-Latmani, Rizlan

    2016-11-15

    Hundreds of tons of depleted uranium (DU) ammunition were used in previous armed conflicts in Iraq, Bosnia and Herzegovina, and Serbia/Kosovo. The majority (>90%) of DU penetrators miss their target and, if left in the environment, corrode in these postconflict zones. Thus, the best way to understand the fate of bulk DU material in the environment is to characterize the corrosion products of intact DU penetrators under field conditions for extended periods of time. However, such studies are scarce. To fill this knowledge gap, we characterized corrosion products formed from two intact DU penetrators that remained in soils in Bosnia and Herzegovina for over seven years. We used a combination of X-ray powder diffraction, electron microscopy, and X-ray absorption spectroscopy. The results show that metaschoepite (UO3(H2O)2) was a main component of the two DU corrosion products. Moreover, studtite ((UO2)O2(H2O)2·2(H2O)) and becquerelite (Ca(UO2)6O4(OH)6·8(H2O)) were also identified in the corrosion products. Their formation through transformation of metaschoepite was a result of the geochemical conditions under which the penetrators corroded. Moreover, we propose that the transformation of metaschoepite to becquerelite or studtite in the DU corrosion products would decrease the potential for mobilization of U from corroded DU penetrators exposed to similar environments in postconflict areas.

  19. Evaluation of the corrosion resistance of Fe-Al-Cr alloys in simulated low NOx environments

    SciTech Connect

    Deacon, R.M.; DuPont, J.N.; Kiely, C.J.; Marder, A.R.; Tortorelli, P.F.

    2009-08-15

    Due to their excellent corrosion resistance, iron aluminum alloys are currently being considered for use as weld claddings in fossil fuel fired power plants. The susceptibility to hydrogen cracking of these alloys at higher aluminum concentrations has led researchers to examine the effect of chromium additions on the corrosion resistance of lower aluminum alloys. In this work, three iron aluminum alloys were exposed to simulated coal combustion environments at 500 and 700{sup o}C for short (100 h) and long (5000 h) isothermal durations. Scanning electron microscopy was used to analyze the corrosion products. All alloys exhibited excellent corrosion resistance during short term exposures. For longer test times, increasing the aluminum concentration improved alloy corrosion resistance. The addition of chromium to the binary iron aluminum alloy prevented the formation iron sulfide and resulted in slower corrosion kinetics. A general classification of the scales developed on these alloys is presented.

  20. Integrating Mobile Phones into Science Teaching to Help Students Develop a Procedure to Evaluate the Corrosion Rate of Iron in Simulated Seawater

    ERIC Educational Resources Information Center

    Moraes, Edgar P.; Confessor, Mario R.; Gasparotto, Luiz H. S.

    2015-01-01

    This article proposes an indirect method to evaluate the corrosion rate of iron nail in simulated seawater. The official procedure is based on the direct measurement of the specimen's weight loss over time; however, a highly precise scale is required and such equipment may not be easily available. On the other hand, mobile phones equipped with…

  1. Integrating Mobile Phones into Science Teaching to Help Students Develop a Procedure to Evaluate the Corrosion Rate of Iron in Simulated Seawater

    ERIC Educational Resources Information Center

    Moraes, Edgar P.; Confessor, Mario R.; Gasparotto, Luiz H. S.

    2015-01-01

    This article proposes an indirect method to evaluate the corrosion rate of iron nail in simulated seawater. The official procedure is based on the direct measurement of the specimen's weight loss over time; however, a highly precise scale is required and such equipment may not be easily available. On the other hand, mobile phones equipped with…

  2. CONDENSED MATTER: STRUCTURE, MECHANICAL AND THERMAL PROPERTIES: Microstructure and Corrosion Performance of Carbonitriding Layers on Cast Iron by Plasma Electrolytic Carbonitriding

    NASA Astrophysics Data System (ADS)

    Pang, Hua; Lv, Guo-Hua; Chen, Huan; Wang, Xin-Quan; Zhang, Gu-Ling; Yang, Si-Ze

    2009-08-01

    The surface carbonitriding of cast iron is investigated in an aqueous solution of acetamide and glycerin. Microstructure, chemical and phase composition and corrosion performance of the carbonitriding layers are investigated by scanning electron microscopy, energy dispersive spectroscopy and x-ray diffraction, as well as potentiodynamic polarization testing. X-ray diffraction results show that the carbonitriding coatings are composed of martensite, austenite(γ-Fe), Fe2C, Fe3C, Fe5C2, FeN and in-Fe2-3N. After the plasma electrolytic carbonitriding treatment the corrosion resistance of cast iron is clearly improved compared to the substrate, and the coatings produced at 350 V for 30s give the best corrosion resistance.

  3. Moessbauer Effect Studies of Crystalline and Amorphous Iron-Based Alloys and of Corrosion Processes at Iron Surfaces.

    NASA Astrophysics Data System (ADS)

    Lin, Mou Ching

    In Part I of this thesis, Mossbauer effect spectroscopy has been used to measure the temperature dependence of the ('57)Fe effective magnetic hyperfine field, H(,eff), and isomer shift, (delta), across the entire Fe(,3)Al(,x)Si(,1 -x) system (0 (LESSTHEQ) x (LESSTHEQ) 1) from77K to the Curie temperature, the latter also being determined from these measurements. The observed dependence of H(,eff) and (delta) on Al concentration can be qualitatively understood in terms of the calculated band structure of Fe(,3)Si. ('57)Fe Mossbauer spectra have been obtained at both liquid nitrogen and room temperatures for a series of metallic glasses Fe(,82)B(,18-x)Be(,x) with 0 (LESSTHEQ) x (LESSTHEQ) 6 in Part II. The width of the probability distribution function of the effective magnetic hyperfine field remains approximately constant at a value of 80 kOe for all samples. However, the most probable value of the effective magnetic hyperfine field at liquid nitrogen temperature initially increases with Be content, but starts to decrease as x exceeds four. The isomer shift has a value of -0.032 mm/sec for samples with x (LESSTHEQ) 4 but changes to -0.050 mm/sec for samples with x > 4. The crystallization products obtained upon annealing the samples were identified. In the last part of this thesis, Mossbauer spectroscopy coupled with electrochemical measurements has been used to study in situ the effects of chloride ions on a passivated iron surface in boric acid-sodium borate buffer solution at a pH of 8.4. The Mossbauer spectrum of the oxide film formed after breakdown of the passive film by aggressive chloride ions consists of a doublet with line-width of 0.51 (+OR-) 0.03 mm/sec, isomer shift of 0.35 (+OR-) 0.02 mm/sec relative to the metallic iron, and quadrupole splitting of 0.79 (+OR-) 0.01 mm/sec. The quadrupole splitting differs from that of the passive film which has line-widths of 0.55 (+OR-) 0.08 mm/sec, an isomer shift of 0.36 (+OR-) 0.01 mm/sec, and a quadrupole

  4. Characterization of uranium corrosion product colloids by dynamic light scattering.

    SciTech Connect

    Mertz, C.; Bowers, D.; Goldberg, M.; Shelton-Davis, C.

    2000-11-16

    The Department of Energy plans to dispose of approximately 2100 metric tons of spent metallic uranium fuel in the mined repository at Yucca Mountain. Laboratory studies at Argonne National Laboratory have shown that corrosion of metallic uranium fuel with groundwater generates significant quantities of stable colloids. This finding is considered very important in light of the recent report (1) of rapid subsurface transport of radionuclides at the Nevada Test Site via colloids. Thus, sparingly soluble radionuclides can be transported with the colloids through the subsurface aqueous environment to much greater distances than is predicted based on the aqueous volubility of the radionuclides alone. Accordingly, characterization of colloids generated by fuel corrosion is necessary for assessing the long-term fate and transport of radionuclides in the repository environment.

  5. Iron Depletion Enhances Production of Antimicrobials by Pseudomonas aeruginosa

    PubMed Central

    Nguyen, Angela T.; Jones, Jace W.; Ruge, Max A.; Kane, Maureen A.

    2015-01-01

    ABSTRACT Cystic fibrosis (CF) is a heritable disease characterized by chronic, polymicrobial lung infections. While Staphylococcus aureus is the dominant lung pathogen in young CF patients, Pseudomonas aeruginosa becomes predominant by adulthood. P. aeruginosa produces a variety of antimicrobials that likely contribute to this shift in microbial populations. In particular, secretion of 2-alkyl-4(1H)-quinolones (AQs) contributes to lysis of S. aureus in coculture, providing an iron source to P. aeruginosa both in vitro and in vivo. We previously showed that production of one such AQ, the Pseudomonas quinolone signal (PQS), is enhanced by iron depletion and that this induction is dependent upon the iron-responsive PrrF small RNAs (sRNAs). Here, we demonstrate that antimicrobial activity against S. aureus during coculture is also enhanced by iron depletion, and we provide evidence that multiple AQs contribute to this activity. Strikingly, a P. aeruginosa ΔprrF mutant, which produces very little PQS in monoculture, was capable of mediating iron-regulated growth suppression of S. aureus. We show that the presence of S. aureus suppresses the ΔprrF1,2 mutant's defect in iron-regulated PQS production, indicating that a PrrF-independent iron regulatory pathway mediates AQ production in coculture. We further demonstrate that iron-regulated antimicrobial production is conserved in multiple P. aeruginosa strains, including clinical isolates from CF patients. These results demonstrate that iron plays a central role in modulating interactions of P. aeruginosa with S. aureus. Moreover, our studies suggest that established iron regulatory pathways of these pathogens are significantly altered during polymicrobial infections. IMPORTANCE Chronic polymicrobial infections involving Pseudomonas aeruginosa and Staphylococcus aureus are a significant cause of morbidity and mortality, as the interplay between these two organisms exacerbates infection. This is in part due to enhanced

  6. Mass Transfer of Corrosion Products in the Nonisothermal Sodium Loop of a Fast Reactor

    NASA Astrophysics Data System (ADS)

    Varseev, E. V.; Alekseev, V. V.

    2014-11-01

    The mass transfer of the products of corrosion of the steel surface of the sodium loop of a fast nuclear power reactor was investigated for the purpose of optimization of its parameters. The problem of deposition of the corrosion products on the surface of the heat-exchange unit of the indicated loop was considered. Experimental data on the rate of accumulation of deposits in the channel of this unit and results of the dispersion analysis of the suspensions contained in the sodium coolant are presented.

  7. Studies of volatile high temperature corrosion products via the free-jet MBMS technique

    SciTech Connect

    Jacobson, N.S.

    1995-03-01

    In high temperature applications such as heat engines, heat exchangers, and chemical process plants, metal and ceramic structural materials are exposed to harsh chemical environments. It is important to understand the mechanism of corrosion of these materials under such conditions. Most laboratory studies of corrosion involve a sensitive microbalance with the sample suspended in a furnace and particular gas atmosphere (thermogravimetric apparatus--TGA). This system allows one to follow the kinetics of reaction and then characterize the corrosion products. Corrosion products are often condensed phase oxides, sulfides, carbides, etc. However, they may often be volatile products such as volatile oxides, hydroxides, chlorides, and oxychlorides. In a TGA, these form as down-stream deposits, which must be chemically analyzed after an experiment. In such a {open_quotes}pseudo-transpiration{close_quotes} experiment, speculations can then be made regarding the composition of these vapor species. Clearly, an in-situ mass spectrometric sampling method is far superior for such analysis. The free-jet expansion, molecular beam mass spectrometric technique allows direct identification of these species. The features of this technique--a rapid transition to collisionless flow, beam cooling, and a high velocity molecular beam--preserve the chemical and dynamic integrity of the beam. In this paper, several studies on volatile corrosion products will be summarized. It will be shown how the mass spectrometric results are combined with other data to elucidate the reaction mechanism. These studies fall into two categories: volatile chlorides and oxychlorides, and volatile hydroxides. Corrosion by chlorine occurs in waste incineration and chemical process plants; formation of volatile hydroxides occurs in combustion environments since water is always a product of combustion.

  8. Corrosion Testing in Support of the Accelerator Production of Tritium Program

    SciTech Connect

    Chandler, G.

    2000-11-07

    The Accelerator Production of Tritium Project is part of the United States Department of Energy strategy to meet the nation's tritium needs. The project involves the design of a proton beam accelerator, which will produce tritium through neutron/proton interaction with helium-3. Design, construction and operation of this one-of-a-kind facility will involve the utilization of a wide variety of materials exposed to unique conditions, including elevated temperature and high-energy mixed-proton and -neutron spectra. A comprehensive materials test program was established by the APT project which includes the irradiation of structural materials by exposure to high-energy protons and neutrons at the Los Alamos Neutron Science Center at the Los Alamos National Laboratory. Real-time corrosion measurements were performed on specially designed corrosion probes in water irradiated by an 800 MeV proton beam. The water test system provided a means for measuring water chemistry, dissolved hydroge n concentration, and the effects of water radiolysis and water quality on corrosion rate. The corrosion probes were constructed of candidate APT materials alloy 718, 316L stainless steel, 304L stainless steel, and 6061 Aluminum (T6 heat treatment), and alternate materials 5052 aluminum alloy, alloy 625, and C276. Real-time corrosion rates during proton irradiation increased with proton beam current. Efforts are continuing to determine the effect of proton beam characteristics and mixed-particle flux on the corrosion rate of materials located directly in the proton beam. This paper focuses on the real-time corrosion measurements of materials located in the supply stream and return stream of the water flow line to evaluate effects of long-lived radiolysis products and water chemistry on the corrosion rates of materials. In general, the corrosion rates for the out-of-beam probes were low and were affected mainly by water conductivity. The data indicate a water conductivity threshold e xists

  9. Application of Mössbauer spectroscopy on corrosion products of NPP

    NASA Astrophysics Data System (ADS)

    Dekan, J.; Lipka, J.; Slugeň, V.

    2013-04-01

    Steam generator (SG) is generally one of the most important components at all nuclear power plants (NPP) with close impact to safe and long-term operation. Material degradation and corrosion/erosion processes are serious risks for long-term reliable operation. Steam generators of four VVER-440 units at nuclear power plants V-1 and V-2 in Jaslovske Bohunice (Slovakia) were gradually changed by new original "Bohunice" design in period 1994-1998, in order to improve corrosion resistance of SGs. Corrosion processes before and after these design and material changes in Bohunice secondary circuit were studied using Mössbauer spectroscopy during last 25 years. Innovations in the feed water pipeline design as well as material composition improvements were evaluated positively. Mössbauer spectroscopy studies of phase composition of corrosion products were performed on real specimens scrapped from water pipelines or in form of filters deposits. Newest results in our long-term corrosion study confirm good operational experiences and suitable chemical regimes (reduction environment) which results mostly in creation of magnetite (on the level 70 % or higher) and small portions of hematite, goethite or hydrooxides. Regular observation of corrosion/erosion processes is essential for keeping NPP operation on high safety level. The output from performed material analyses influences the optimisation of operating chemical regimes and it can be used in optimisation of regimes at decontamination and passivation of pipelines or secondary circuit components. It can be concluded that a longer passivation time leads more to magnetite fraction in the corrosion products composition.

  10. A study on the production processes of granulated iron

    NASA Astrophysics Data System (ADS)

    Nokhrina, O. I.; Rozhikhina, I. D.; Khodosov, I. E.

    2016-09-01

    The results of theoretical and experimental studies on the production process of high-quality granulated iron using hematite-magnetite iron ore and coal of different brands as a raw material are presented. According to the research the optimal coal consumption, temperature and time parameters of the metallization process, necessary for obtaining metallized materials with the specified composition and metallization degree, are defined. The conditions for the formation of metal granules with high content (over 98%) of primary iron are found. The process includes two stages: initially the solid-phase reduction of iron from oxides with production of metallized sponge material is carried out, further as the temperature increases the separation of slag and metal phases takes place.

  11. Microbiologically Influenced Corrosion: Causative Organisms and Mechanisms

    DTIC Science & Technology

    2012-01-31

    natural iron oxyhydroxide biominerali/.ation products, Science 289 751-754. Beech IB and Cheung CWS (1995) Interactions of exopolymers produced by...Girasole M. Fra/.er BH, Nesterova MV. Fakra S and Banfield JF(2004)The role of microbial polymers in template mineral growth. Science 303 1656-2658. (hau... enviromental composition as a potential method for reversing microbiologically influenced corrosion, Corrosion (NAC’E) International. Houston. Texas

  12. Role of B/sup +/ and N/sub 2//sup +/ ion implantation in the corrosion behavior of high purity iron and 440 C stainless steel

    SciTech Connect

    Kim, H.J.

    1985-01-01

    The change in the surface composition and structure by ion implantation was examined to determine the mechanisms by which ion implantation affected the corrosion properties of the substrate. The corrosion behavior of ion implanted samples tested in deaerated 1 N H/sub 2/SO/sub 4/ and 0.1 M NaCl solutions was compared with that of the unimplanted samples measured by the potentiodynamic and potentiostatic polarization methods. Boron implantation into iron and 440 C stainless steel with a fluence of 2 x 10/sup 17/ ions cm/sup -2/ at 40 keV changed the surface structure to either an amorphous or a fine microcrystalline state. Nitrogen implantation with a fluence of 1 x 10/sup 17/ and 2.5 x 10/sup 17/ ions cm/sup -2/ at 50 keV and 100 keV, respectively, produced nitrides in iron and the matrix of 440 C. The higher dose and higher voltage implantation of N/sub 2//sup +/ produced a more disturbed surface layer than did implantation at the other condition. Implantation of boron into iron increased the corrosion resistance of the iron in deaerated 1 N H/sub 2/SO/sub 4/. However, the same surface showed a decrease in the pitting resistance in deaerated 0.1 M NaCl when compared to the unimplanted iron. Nitrogen implantation with a fluence of 2.5 x 10/sup 17/ ions cm/sup -2/ at 100 keV produced a significant increase in both general and pitting corrosion resistance of iron. Nitrogen implantation with a fluence of 1 x 10/sup 17/ ions cm/sup -2/ at 50 keV produced little or no improvement in the corrosion resistance of iron in deaerated 1 N H/sub 2/SO/sub 4/, and a tendency for increased pitting in deaerated 0.1 M NaCl. Boron implantation into AISI 440C stainless steel markedly increased the corrosion resistance in deaerated 1 N H/sub 2/SO/sub 4/.

  13. Modeling of hydrogen sulfide oxidation in concrete corrosion products from sewer pipes.

    PubMed

    Jensen, Henriette Stokbro; Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild; Vollertsen, Jes

    2009-04-01

    Abiotic and biotic oxidation of hydrogen sulfide related to concrete corrosion was studied in corrosion products originating from a sewer manhole. The concrete corrosion products were suspended in an acidic solution, mimicking the conditions in the pore water of corroded concrete. The removal of hydrogen sulfide and dissolved oxygen was measured in parallel in the suspension, upon which the suspension was sterilized and the measurement repeated. The results revealed the biotic oxidation to be fast compared with the abiotic oxidation. The stoichiometry of the hydrogen sulfide oxidation was evaluated using the ratio between oxygen and hydrogen sulfide uptake. The ratio for the biotic oxidation pointed in the direction of elemental sulfur being formed as an intermediate in the oxidation of hydrogen sulfide to sulfuric acid. The experimental results were applied to suggest a hypothesis and a mathematical model describing the hydrogen sulfide oxidation pathway in a matrix of corroded concrete.

  14. Influence of solid corrosion by-products on the consumption of dissolved oxygen in copper pipes

    SciTech Connect

    Vargas, Ignacio T.; Alsina, Marco A.; Pastén, Pablo A.; Pizarro, Gonzalo E.

    2009-06-12

    Research on corrosion of copper pipes has given little consideration to the influence of solid corrosion by-products on the processes occurring at the metal-liquid interface. Consequently, the effect of such solid phases on the rate of dissolved oxygen (DO) consumption remains poorly understood. In-situ experiments were performed in copper pipes under different carbonate concentrations and ageing times. Our results show that the amount of solid corrosion by-products and concentration of hydrogen ions affect the rate of DO consumption during stagnation. Furthermore, our findings support the existing hypothesis that the available concentration of hydrogen ions, rather than DO, is the limiting factor for copper release into drinking water.

  15. Iron atoms redistribution in oxide films of Zr-Fe, Zr-Fe-Cu alloys during corrosion in autoclave at 350°C

    NASA Astrophysics Data System (ADS)

    Filippov, V.; Bateev, A.

    2016-04-01

    The data on changes of iron atoms state in the oxide films of binary Zr-1.24 mas.%Fe and ternary Zr-1.39 mas.%Fe-0.60 mas.%Cu zirconium alloys are obtained. Alloys are subjected to corrosion tests under autoclave conditions at 350°C temperature in a steam-water environment under pressure p = 16.8 MPa. In initial specimens of the alloys the iron atoms are in the form of intermetallic compounds. In oxide films the decomposition of intermetallic compounds and formation of new compounds occurs with structural phase distortion. In the oxide films metallic the metallic iron particles α-Fe, iron oxide in the form of hematite α-Fe2O3, solid solutions of iron ions in ZrO2 are formed. The phase composition of the oxide films depends on the alloy composition and changes during the growth process of the oxide film.

  16. An investigation of the corrosion of polycrystalline iron by XPS, TMS and CEMS

    NASA Astrophysics Data System (ADS)

    Idczak, K.; Idczak, R.; Konieczny, R.

    2016-06-01

    The room temperature studies of polycrystalline iron exposed to air at various temperatures were performed using: the transmission Mössbauer spectroscopy (TMS), the conversion electron Mössbauer spectroscopy (CEMS) and the X-ray photoelectron spectroscopy (XPS). The unique combination of these techniques allows to determine changes of chemical composition and content of iron oxides simultaneously on the surface region, the 300 nm pre-surface region and the bulk of the samples. The results show that the chemical composition of samples changes significantly and it is strongly dependent on temperature at which the iron sample is exposed to air as well as on investigated region.

  17. 76 FR 4291 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Partial Rescission of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-25

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... administrative review of the countervailing duty order on corrosion- resistant carbon steel flat products from... ] requests for administrative review and partial revocation of the countervailing duty order on...

  18. 77 FR 301 - Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea: Institution of Five-Year...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-04

    ... Reviews Concerning the Countervailing Duty Order on Corrosion-Resistant Carbon Steel Flat Products From Korea and the Antidumping Duty Orders on Corrosion-Resistant Carbon Steel Flat Products From Germany and... (19 U.S.C. 1675(c)) (the Act) to determine whether revocation of the countervailing duty order on...

  19. Sulphide production and corrosion in seawaters during exposure to FAME diesel.

    PubMed

    Lee, Jason S; Ray, Richard I; Little, Brenda J; Duncan, Kathleen E; Oldham, Athenia L; Davidova, Irene A; Suflita, Joseph M

    2012-01-01

    Experiments were designed to evaluate the corrosion-related consequences of storing/transporting fatty acid methyl ester (FAME) alternative diesel fuel in contact with natural seawater. Coastal Key West, FL (KW), and Persian Gulf (PG) seawaters, representing an oligotrophic and a more organic- and inorganic mineral-rich environment, respectively, were used in 60 day incubations with unprotected carbon steel. The original microflora of the two seawaters were similar with respect to major taxonomic groups but with markedly different species. After exposure to FAME diesel, the microflora of the waters changed substantially, with Clostridiales (Firmicutes) becoming dominant in both. Despite low numbers of sulphate-reducing bacteria in the original waters and after FAME diesel exposure, sulphide levels and corrosion increased markedly due to microbial sulphide production. Corrosion morphology was in the form of isolated pits surrounded by an intact, passive surface with the deepest pits associated with the fuel/seawater interface in the KW exposure. In the presence of FAME diesel, the highest corrosion rates measured by linear polarization occurred in the KW exposure correlating with significantly higher concentrations of sulphur and chlorine (presumed sulphide and chloride, respectively) in the corrosion products.

  20. Corrosion considerations for thermochemical biomass liquefaction process systems in biofuel production

    SciTech Connect

    Brady, Michael P.; Keiser, James R.; Leonard, Donovan N.; Whitmer, Lysle; Thomson, Jeffery K.

    2014-11-11

    Thermochemical liquifaction processing of biomass to produce bio-derived fuels (e.g. gasoline, jet fuel, diesel, home heating oil, etc.) is of great recent interest as a renewable energy source. Approaches under investigation include direct liquefaction, hydrothermal liquefaction, hydropyrolysis, fast pyrolysis, etc. to produce energy dense liquids that can be utilized as produced or further processed to provide products of higher value. An issue with bio-oils is that they tend to contain significant concentrations of organic compounds, which make the bio-oil acidic and a potential source of corrosion issues in in transport, storage, and use. Efforts devoted to modified/further processing of bio-oils to make them less corrosive are currently being widely pursued. Another aspect that must also be addressed is potential corrosion issues in the bio-oil liquefaction process equipment itself. Depending on the specific process, bio-oil liquefaction production temperatures can reach up to 400-600 °C, and involve the presence of aggressive sulfur, and halide species from both the biomass used and/or process additives. Detailed knowledge of the corrosion resistance of candidate process equipment alloys in these bio-oil production environments is currently lacking. Lastly, this paper summarizes our recent, ongoing efforts to assess the extent to which corrosion of bio-oil process equipment may be an issue, with the ultimate goal of providing the basis to select the lowest cost alloy grades capable of providing the long-term corrosion resistance needed for future bio-oil production plants.

  1. Corrosion considerations for thermochemical biomass liquefaction process systems in biofuel production

    DOE PAGES

    Brady, Michael P.; Keiser, James R.; Leonard, Donovan N.; ...

    2014-11-11

    Thermochemical liquifaction processing of biomass to produce bio-derived fuels (e.g. gasoline, jet fuel, diesel, home heating oil, etc.) is of great recent interest as a renewable energy source. Approaches under investigation include direct liquefaction, hydrothermal liquefaction, hydropyrolysis, fast pyrolysis, etc. to produce energy dense liquids that can be utilized as produced or further processed to provide products of higher value. An issue with bio-oils is that they tend to contain significant concentrations of organic compounds, which make the bio-oil acidic and a potential source of corrosion issues in in transport, storage, and use. Efforts devoted to modified/further processing of bio-oilsmore » to make them less corrosive are currently being widely pursued. Another aspect that must also be addressed is potential corrosion issues in the bio-oil liquefaction process equipment itself. Depending on the specific process, bio-oil liquefaction production temperatures can reach up to 400-600 °C, and involve the presence of aggressive sulfur, and halide species from both the biomass used and/or process additives. Detailed knowledge of the corrosion resistance of candidate process equipment alloys in these bio-oil production environments is currently lacking. Lastly, this paper summarizes our recent, ongoing efforts to assess the extent to which corrosion of bio-oil process equipment may be an issue, with the ultimate goal of providing the basis to select the lowest cost alloy grades capable of providing the long-term corrosion resistance needed for future bio-oil production plants.« less

  2. Corrosion Considerations for Thermochemical Biomass Liquefaction Process Systems in Biofuel Production

    NASA Astrophysics Data System (ADS)

    Brady, M. P.; Keiser, J. R.; Leonard, D. N.; Whitmer, L.; Thomson, J. K.

    2014-12-01

    Thermochemical liquefaction processing of biomass to produce bio-derived fuels (e.g., gasoline, jet fuel, diesel, home heating oil, etc.) is of great recent interest as a renewable energy source. Approaches under investigation include direct liquefaction, hydrothermal liquefaction, hydropyrolysis, fast pyrolysis, etc., to produce energy dense liquids that can be utilized as produced or further processed to provide products of higher value. An issue with bio-oils is that they tend to contain significant concentrations of organic oxygenates, including acids, which make the bio-oil a potential source of corrosion issues in transport, storage, and use. Efforts devoted to modified/further processing of bio-oils to make them less corrosive are currently being widely pursued. Another issue that must also be addressed in bio-oil liquefaction is potential corrosion issues in the process equipment. Depending on the specific process, bio-oil liquefaction production temperatures are typically in the 300-600°C range, and the process environment can contain aggressive sulfur and halide species from both the biomass used and/or process additives. Detailed knowledge of the corrosion resistance of candidate process equipment alloys in these bio-oil production environments is currently lacking. This paper summarizes recent, ongoing efforts to assess the extent of corrosion of bio-oil process equipment, with the ultimate goal of providing a basis for the selection of the lowest cost alloy grades capable of providing the long-term corrosion resistance needed for future bio-oil production plants.

  3. Iron-niobium-aluminum alloy having high-temperature corrosion resistance

    DOEpatents

    Hsu, Huey S.

    1988-04-14

    An alloy for use in high temperature sulfur and oxygen containing environments, having aluminum for oxygen resistance, niobium for sulfur resistance and the balance iron, is discussed. 4 figs., 2 tabs.

  4. Neutrophilic Iron-Oxidizing "Zetaproteobacteria" and Mild Steel Corrosion in Nearshore Marine Environments

    DTIC Science & Technology

    2011-02-16

    15, 17, 21). Cultivation-independent studies have estab- lished that a novel candidate class of Proteobacteria , the "Zetaproteobacteria" tend to be... proteobacteria , Mariprofundus ferrooxydans, from an iron mat at Loihi Seamount, provided phylogenctic confirmation of the uniqueness of... Proteobacteria , based on the SSU rRNA gene (A), the LSU rRNA gene (B), and the gyrB gene (C). The tree A oulgroup is the iron oxide stalk-forming freshwater

  5. Hydroxide nanoparticles for deacidification and concomitant inhibition of iron-gall ink corrosion of paper.

    PubMed

    Poggi, Giovanna; Giorgi, Rodorico; Toccafondi, Nicola; Katzur, Verena; Baglioni, Piero

    2010-12-21

    This Article reports an investigation on the use of magnesium hydroxide nanoparticles dispersed in alcohols to inhibit two different and synergistic degradation processes usually affecting historically valuable manuscripts and, more generally, paper documents. We show that the preservation of paper from acid hydrolysis and oxidative ink corrosion can be achieved by stabilizing the final pH of deacidified paper around 6.5 to 7.5. Reactive magnesium hydroxide nanoparticles with a narrow size distribution, obtained by using a novel synthetic procedure, are very efficient in controlling paper's pH to avoid further degradation of cellulose from acid hydrolysis, oxidative ink corrosion, or both. The deacidification and antioxidant actions of magnesium hydroxide nanoparticles are compared with magnesium oxide particles present in one of the best mass deacidification methods (Bookkeeper).

  6. Study of corrosion in archaeological gilded irons by Raman imaging and a coupled scanning electron microscope-Raman system.

    PubMed

    Veneranda, Marco; Costantini, Ilaria; de Vallejuelo, Silvia Fdez-Ortiz; Garcia, Laura; García, Iñaki; Castro, Kepa; Azkarate, Agustín; Madariaga, Juan Manuel

    2016-12-13

    In this work, analytical and chemical imaging tools have been applied to the study of a gilded spur found in the medieval necropolis of Erenozar (Bizkaia, Spain). As a first step, a lot of portable equipment has been used to study the object in a non-invasive way. The hand-held energy-dispersive X-ray fluorescence equipment allowed us to characterize the artefact as a rare example of an iron matrix item decorated by means of a fire gilding technique. On the other hand, the use of a portable Raman system helped us to detect the main degradation compounds affecting the spur. Afterwards, further information was acquired in the laboratory by analysing detached fragments. The molecular images obtained using confocal Raman microscopy permitted us to characterize the stratigraphic succession of iron corrosions. Furthermore, the combined use of this technique with a scanning electron microscope (SEM) was achieved owing to the use of a structural and chemical analyser interface. In this way, the molecular characterization, enhanced by the magnification feature of the SEM, allowed us to identify several micrometric degradation compounds. Finally, the effectiveness of one of the most used desalination baths (NaOH) was evaluated by comparing its effects with those provided by a reference bath (MilliQ). The comparison proved that basic treatment avoided any side effects on the spur decorated by fire gilding, compensating for the lack of bibliographic documentation in this field.This article is part of the themed issue 'Raman spectroscopy in art and archaeology'.

  7. Study of corrosion in archaeological gilded irons by Raman imaging and a coupled scanning electron microscope-Raman system

    NASA Astrophysics Data System (ADS)

    Veneranda, Marco; Costantini, Ilaria; de Vallejuelo, Silvia Fdez-Ortiz; Garcia, Laura; García, Iñaki; Castro, Kepa; Azkarate, Agustín; Madariaga, Juan Manuel

    2016-12-01

    In this work, analytical and chemical imaging tools have been applied to the study of a gilded spur found in the medieval necropolis of Erenozar (Bizkaia, Spain). As a first step, a lot of portable equipment has been used to study the object in a non-invasive way. The hand-held energy-dispersive X-ray fluorescence equipment allowed us to characterize the artefact as a rare example of an iron matrix item decorated by means of a fire gilding technique. On the other hand, the use of a portable Raman system helped us to detect the main degradation compounds affecting the spur. Afterwards, further information was acquired in the laboratory by analysing detached fragments. The molecular images obtained using confocal Raman microscopy permitted us to characterize the stratigraphic succession of iron corrosions. Furthermore, the combined use of this technique with a scanning electron microscope (SEM) was achieved owing to the use of a structural and chemical analyser interface. In this way, the molecular characterization, enhanced by the magnification feature of the SEM, allowed us to identify several micrometric degradation compounds. Finally, the effectiveness of one of the most used desalination baths (NaOH) was evaluated by comparing its effects with those provided by a reference bath (MilliQ). The comparison proved that basic treatment avoided any side effects on the spur decorated by fire gilding, compensating for the lack of bibliographic documentation in this field. This article is part of the themed issue "Raman spectroscopy in art and archaeology".

  8. Oxidation of sulfoxides and arsenic(III) in corrosion of nanoscale zero valent iron by oxygen: evidence against ferryl ions (Fe(IV)) as active intermediates in Fenton reaction.

    PubMed

    Pang, Su-Yan; Jiang, Jin; Ma, Jun

    2011-01-01

    Previous studies have shown that the corrosion of zerovalent iron (ZVI) by oxygen (O(2)) via the Fenton reaction can lead to the oxidation of various organic and inorganic compounds. However, the nature of the oxidants involved (i.e., ferryl ion (Fe(IV)) versus hydroxyl radical (HO(•))) is still a controversial issue. In this work, we reevaluated the relative importance of these oxidants and their role in As(III) oxidation during the corrosion of nanoscale ZVI (nZVI) in air-saturated water. It was shown that Fe(IV) species could react with sulfoxides (e.g., dimethyl sulfoxide, methyl phenyl sulfoxide, and methyl p-tolyl sulfoxide) through a 2-electron transfer step producing corresponding sulfones, which markedly differed from their HO(•)-involved products. When using these sulfoxides as probe compounds, the formation of oxidation products indicative of HO(•) but no generation of sulfone products supporting Fe(IV) participation were observed in the nZVI/O(2) system over a wide pH range. As(III) could be completely or partially oxidized by nZVI in air-saturated water. Addition of scavengers for solution-phase HO(•) and/or Fe(IV) quenched As(III) oxidation at acidic pH but had little effect as solution pH increased, highlighting the importance of the heterogeneous iron surface reactions for As(III) oxidation at circumneutral pH.

  9. "A L C L A D" A New Corrosion Resistant Aluminum Product

    NASA Technical Reports Server (NTRS)

    Dix, E H , Jr

    1927-01-01

    Described here is a new corrosion resistant aluminum product which is markedly superior to the present strong alloys. Its use should result in greatly increased life of a structural part. Alclad is a heat-treated aluminum, copper, manganese, magnesium alloy that has the corrosion resistance of pure metal at the surface and the strength of the strong alloy underneath. Of particular importance is the thorough character of the union between the alloy and the pure aluminum. Preliminary results of salt spray tests (24 weeks of exposure) show changes in tensile strength and elongation of Alclad 17ST, when any occurred, to be so small as to be well within the limits of experimental error. Some surface corrosion of the pure metal had taken place, but not enough to cause the specimens to break through those areas.

  10. Corrosion fatigue of iron-chromium-nickel alloys: Fracture mechanics, microstructure and chemistry

    SciTech Connect

    Wei, R.P.

    1993-01-25

    Phase transformation and cracking during RT aging of charged, high-purity Fe18Cr12Ni alloy and commerical 304 ss were examined; results show that [epsilon]* (hcp) hydride formed on Fe18Cr12Ni upon charging, and it decomposed rapidly to form first [epsilon] and then [alpha]' martensite. Morphology of fracture surfaces of Fe18Cr12Ni produced by corrosion fatigue in NaCl solutions and in hydrogen was found to be identical. Effort was made to examine the approaches and methodologies used in service life predictions and reliability analyses.

  11. Iron-Oxidizing Bacteria: A Review of Corrosion Mechanisms in Fresh Water and Marine Environments

    DTIC Science & Technology

    2010-01-01

    chemical composition by %, C, 0.17-0.23; Mn, 0.3-0.6; P max, 0.04; S max, 0.05 and Fe, balance) was machined into discs 1.58 cm (5/8 in.) dia. x 0.158...chlorides that are extremely corrosive. Under these circumstances, pitting involves the conventional features of differential aeration, a large...tubing filled with saturated KC1 solution and sealed with glass frits on either end. Electrical conduction was achieved by placing each end of the salt

  12. Constitution of green rust and its significance to the corrosion of steel in Portland cement

    SciTech Connect

    Sagoe-Crentsil, K.K. . Div. of Building Construction and Engineering); Glasser, F.P. . Dept. of Chemistry)

    1993-06-01

    Studies of the corrosion of pure iron showed green rust, approximately Fe[sub 4][sup 2+]Fe[sub 2][sup 3+] (OH)[sub 12](Cl,OH)[sub 2], was a stable corrosion product at high pH and low E[sub h] in the presence of chloride. The structure, constitution, preparation, and characterization of green rust was reviewed. A diagram relevant to the corrosion of iron in cement, constructed for pH 12, showed stability fields of green rust, [alpha],[delta] FeO(OH), and [beta]FeO(OH,Cl). Overall implications of chloride to the corrosion process were investigated.

  13. 78 FR 55241 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Preliminary Results of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-10

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...) is conducting an administrative review of the countervailing duty (CVD) order on corrosion-resistant.... SUPPLEMENTARY INFORMATION: Scope of the Order The merchandise covered by this Order \\2\\ is certain...

  14. Characterisation of secondary products of uranium-aluminium material test reactor fuel element corrosion in repository-relevant brine

    NASA Astrophysics Data System (ADS)

    Mazeina, L.; Curtius, H.; Fachinger, J.; Odoj, R.

    2003-11-01

    Corrosion experiments with non-irradiated uranium-aluminium fuel elements were performed in MgCl 2-rich brine. Distribution analysis of corroded material showed that about 90% of the initially available metallic U and Al precipitated. Investigations of these secondary corrosion products provided that one component is a Mg-Al-Cl-hydrotalcite.

  15. Iron ore mines leachate potential for oxyradical production.

    PubMed

    Hamoutene, D; Rahimtula, A; Payne, J

    2000-06-01

    The ecotoxicological effects of mining effluents is coming under much greater scrutiny. It appears necessary to explore possible health effects in association with iron ore mining effluents. The present results clearly demonstrate that iron-ore leachate is not an inert media but has the potential to induce lipid peroxidation. Peroxidation was assessed by measuring oxygen consumption in the presence of a reducing agent such as ascorbate or NADPH and a chelator such as EDTA. Labrador iron ore is an insoluble complex crystalline material containing a mixture of metals (Fe, Al, Ti, Mn, Mg,ellipsis, ) in contrast to the iron sources used for normal lipid peroxidation studies. The metal of highest percentage is iron (59. 58%), a metal known to induce oxyradical production. Iron ore powder initiated ascorbic acid-dependent lipid peroxidation (nonenzymatic) in liposomes, lipids extracted from rat and salmon liver microsomes, and intact salmon liver microsomes. It also revealed an inhibitory effect of NADPH-dependent microsomes lipid peroxidation as well as on NADPH cytochrome c reductase activity. However, nonenzymatic peroxidation in rat liver microsomes was not significantly inhibited. Cytochrome P450 IA1- and IIB1-dependent enzymatic activities as well as P450 levels were not affected. The inhibition could be due to one of the other components of iron ore leachate (Mn, Al,ellipsis, ). These effects of iron-ore leachate indicate that a potential toxicity could be associated with its release into lakes. Further studies are necessary to explore in vivo effects on aquatic animals. Copyright 2000 Academic Press.

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

    SciTech Connect

    Videla, H.A.; Mele, M.F.L. de; Swords, C.; Edyvean, R.G.J.; Beech, I.B.

    1999-11-01

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

  17. Iron management and production of electricity by microorganisms.

    PubMed

    Folgosa, Filipe; Tavares, Pedro; Pereira, Alice S

    2015-10-01

    The increasing dependency on fossil fuels has driven researchers to seek for alternative energy sources. Renewable energy sources such as sunlight, wind, or water are the most common. However, since the 1990s, other sources for energy production have been studied. The use of microorganisms such as bacteria or archaea to produce energy is currently in great progress. These present several advantages even when compared with other renewable energy sources. Besides the energy production, they are also involved in bioremediation such as the removal of heavy metal contaminants from soils or wastewaters. Several research groups have demonstrated that these organisms are able to interact with electrodes via heme and non-heme iron proteins. Therefore, the role of iron as well as iron metabolism in these species must be of enormous relevance. Recently, the influence of cellular iron regulation by Fur in the Geobacter sulfurreducens growth and ability to produce energy was demonstrated. In this review, we aim to briefly describe the most relevant proteins involved in the iron metabolism of bacteria and archaea and relate them and their biological function with the ability of selected organisms to produce energy.

  18. Corrosion study of iron-cobalt alloys for MRI-based propulsion embedded in untethered microdevices operating in the vascular network.

    PubMed

    Pouponneau, Pierre; Savadogo, Oumarou; Napporn, Teko; Yahia, L'hocine; Martel, Sylvain

    2010-04-01

    Our group have shown in an experiment performed in the carotid artery of a living swine that magnetic gradients generated by a clinical magnetic resonance imaging (MRI) system could propel and navigate untethered medical microdevices and micro-nanorobots in the human vasculature. The main problem with these devices is that the metal necessary for magnetic propulsion may corrode and induce cytotoxic effects. The challenge, then, is to find an alloy with low corrosion yet providing an adequate magnetization level for propulsion in often stringent physiological conditions. Because of their high magnetization, we studied the corrosion behavior of two iron-cobalt alloys, Permendur (49% Fe, 49% Co, 2% V) and Vacoflux 17 (81% Fe, 17% Co, 2% Cr), in physiological solution by potentiodynamic polarization assay, surface analysis, and corrosion electrolyte analysis. Both alloys exhibited low corrosion parameters such as a corrosion potential (E(corr)) of -0.57 V/SCE and E(corr) of -0.42 V/SCE for Vacoflux 17. The surface of Permendur samples was homogenously degraded. Vacoflux 17 surface was impaired by cracks and crevices. Both alloys had a stoichiometric dissolution in the electrolyte, and they released enough cobalt to induce cytotoxic effects. This study concluded that Fe-Co alloys could be used preferably in medical microdevices if they were coated so as not to come in contact with physiological solutions.

  19. Metabolomic and Metagenomic Analysis of Two Crude Oil Production Pipelines Experiencing Differential Rates of Corrosion.

    PubMed

    Bonifay, Vincent; Wawrik, Boris; Sunner, Jan; Snodgrass, Emily C; Aydin, Egemen; Duncan, Kathleen E; Callaghan, Amy V; Oldham, Athenia; Liengen, Turid; Beech, Iwona

    2017-01-01

    Corrosion processes in two North Sea oil production pipelines were studied by analyzing pig envelope samples via metagenomic and metabolomic techniques. Both production systems have similar physico-chemical properties and injection waters are treated with nitrate, but one pipeline experiences severe corrosion and the other does not. Early and late pigging material was collected to gain insight into the potential causes for differential corrosion rates. Metabolites were extracted and analyzed via ultra-high performance liquid chromatography/high-resolution mass spectrometry with electrospray ionization (ESI) in both positive and negative ion modes. Metabolites were analyzed by comparison with standards indicative of aerobic and anaerobic hydrocarbon metabolism and by comparison to predicted masses for KEGG metabolites. Microbial community structure was analyzed via 16S rRNA gene qPCR, sequencing of 16S PCR products, and MySeq Illumina shotgun sequencing of community DNA. Metagenomic data were used to reconstruct the full length 16S rRNA genes and genomes of dominant microorganisms. Sequence data were also interrogated via KEGG annotation and for the presence of genes related to terminal electron accepting (TEA) processes as well as aerobic and anaerobic hydrocarbon degradation. Significant and distinct differences were observed when comparing the 'high corrosion' (HC) and the 'low corrosion' (LC) pipeline systems, especially with respect to the TEA utilization potential. The HC samples were dominated by sulfate-reducing bacteria (SRB) and archaea known for their ability to utilize simple carbon substrates, whereas LC samples were dominated by pseudomonads with the genetic potential for denitrification and aerobic hydrocarbon degradation. The frequency of aerobic hydrocarbon degradation genes was low in the HC system, and anaerobic hydrocarbon degradation genes were not detected in either pipeline. This is in contrast with metabolite analysis, which demonstrated the

  20. Stress Corrosion Cracking and Oxidation Characteristics of Boride-Strengthend Microcrystalline Iron and Nickel Based Alloys.

    DTIC Science & Technology

    1984-10-22

    through subsequent thermomechanical treatments make this class of alloy attractive for many applications. One such relatively new class of alloys based...crystallizing it in the solid state) using controlled thermal or thermomechanical treatments. Preliminary evaluations of the Fe, Ni, and Co-based micrystalline...and iron in alloys 3 and 4). Each of the four microcrystalline alloys was processed in similar ways. Each alloy was induction melted and chill block

  1. Pacific patterns of dust deposition, iron supply and export production

    NASA Astrophysics Data System (ADS)

    Winckler, G.; Anderson, R. F.; Park, J.; Schwartz, R.; Pahnke, K.; Struve, T.; Lamy, F.; Gersonde, R.

    2015-12-01

    The scarcity of iron limits marine export production and carbon uptake in about a quarter of the global ocean where the surface concentration of nitrate and phosphate is high, as biological utilization of these macronutrients is incomplete. Of these high nutrient low chlorophyll (HNLC) regions, the Southern Ocean is the region where variations in iron availability can have the largest effect on Earth's carbon cycle through its fertilizing effect on marine ecosystems, both in the modern and in the past. Recent work in the Subantarctic South Atlantic (Martínez-Garcia et al., 2009, 2014, Anderson et al., 2014) suggests that dust-driven iron fertilization lowered atmospheric CO2 by up to 40 ppm in the latter half of each glacial cycle of the late Pleistocene, with the increase in Subantarctic productivity consuming a greater fraction of the surface nutrients and thus driving more storage of carbon in the ocean interior. The other sectors of the Southern Ocean remain poorly constrained, including the Pacific Sector, that accounts for the largest surface area of the Subantarctic Southern Ocean. Here we report records of dust deposition, iron supply and export production from a set of cores from the Subantarctic Pacific (PS75, Lamy et al 2014) and initial results about the origin of dust transported to the Subantarctic Pacific Ocean from radiogenic isotopes and rare earth elements. We test how tightly dust and biological productivity are coupled over glacial/interglacial and millennial timescales in the Subantarctic Pacific and place the region in a context of global patterns of biological productivity, nutrient utilization and iron fertilization by dust, including comparisons to the other Pacific HNLC regions, the Subarctic North Pacific and equatorial Pacific.

  2. Effect of Phosphate on the Corrosion of Carbon Steel and on the Composition of Corrosion Products in Two-Stage Continuous Cultures of Desulfovibrio desulfuricans†

    PubMed Central

    Weimer, Paul J.; Van Kavelaar, Margaret J.; Michel, Charles B.; Ng, Thomas K.

    1988-01-01

    A field isolate of Desulfovibrio desulfuricans was grown in defined medium in a two-stage continuous culture apparatus with different concentrations of phosphate in the feed medium. The first state (V1) was operated as a conventional chemostat (D = 0.045 h−1) that was limited in energy source (lactate) or phosphate. The second stage (V2) received effluent from V1 but no additional nutrients, and contained a healthy population of transiently starved or resting cells. An increase in the concentration of phosphate in the medium fed to V1 resulted in increased corrosion rates of carbon steel in both V1 and V2. Despite the more rapid corrosion observed in growing cultures relative to that in resting cultures, corrosion products that were isolated under strictly anaerobic conditions from the two culture modes had similar bulk compositions which varied with the phosphate content of the medium. Crystalline mackinawite (Fe9S8), vivianite [Fe3(PO4)2 · 8H2O], and goethite [FeO(OH)] were detected in amounts which varied with the culture conditions. Chemical analyses indicated that the S in the corrosion product was almost exclusively in the form of sulfides, while the P was present both as phosphate and as unidentified components, possibly reduced P species. Some differential localization of S and P was observed in intact corrosion products. Cells from lactate-limited, but not from phosphate-limited, cultures contained intracellular granules that were enriched in P and Fe. The results are discussed in terms of several proposed mechanisms of microbiologically influenced corrosion. Images PMID:16347552

  3. Effect of Phosphate on the Corrosion of Carbon Steel and on the Composition of Corrosion Products in Two-Stage Continuous Cultures of Desulfovibrio desulfuricans.

    PubMed

    Weimer, P J; Van Kavelaar, M J; Michel, C B; Ng, T K

    1988-02-01

    A field isolate of Desulfovibrio desulfuricans was grown in defined medium in a two-stage continuous culture apparatus with different concentrations of phosphate in the feed medium. The first state (V1) was operated as a conventional chemostat (D = 0.045 h) that was limited in energy source (lactate) or phosphate. The second stage (V2) received effluent from V1 but no additional nutrients, and contained a healthy population of transiently starved or resting cells. An increase in the concentration of phosphate in the medium fed to V1 resulted in increased corrosion rates of carbon steel in both V1 and V2. Despite the more rapid corrosion observed in growing cultures relative to that in resting cultures, corrosion products that were isolated under strictly anaerobic conditions from the two culture modes had similar bulk compositions which varied with the phosphate content of the medium. Crystalline mackinawite (Fe(9)S(8)), vivianite [Fe(3)(PO(4))(2) . 8H(2)O], and goethite [FeO(OH)] were detected in amounts which varied with the culture conditions. Chemical analyses indicated that the S in the corrosion product was almost exclusively in the form of sulfides, while the P was present both as phosphate and as unidentified components, possibly reduced P species. Some differential localization of S and P was observed in intact corrosion products. Cells from lactate-limited, but not from phosphate-limited, cultures contained intracellular granules that were enriched in P and Fe. The results are discussed in terms of several proposed mechanisms of microbiologically influenced corrosion.

  4. The Role of Oxygen in Anaerobic Microbiologically Influenced Marine Corrosion

    DTIC Science & Technology

    2011-10-01

    12) p. 1173-1188. 12. Hamilton WA (2003) Microbially influenced corrosion as a model system for the study of metal microbe interactions: A unifying...enzyme dehydrogenase, anodic depolarization, production of corrosive iron sulphides, release of exopolymers capable of binding metal ions, sulphide...biofilm is greater than the oxygen diffusion rate, the metal /biofilm interface can become anaerobic and provide a niche for sulphide production by SRB

  5. Excitation of Lamb waves over a large frequency-thickness product range for corrosion detection

    NASA Astrophysics Data System (ADS)

    Zeng, Liang; Luo, Zhi; Lin, Jing; Hua, Jiadong

    2017-09-01

    For corrosion detection, it is often desirable that a Lamb wave mode is highly sensitive to surface thinning and enjoys some degree of mode purity at a particular frequency. In view of this, this paper aims to generate a variety of Lamb wave modes over broad frequency bands to ensure an abundant supply of candidates for corrosion detection, and further, establish a strategy to find appropriate operation points efficiently and effectively. Firstly, a short-duration laser pulse is applied to generate Lamb waves over a large frequency-thickness product range. The selection of symmetric modes or anti-symmetric modes is obtained by addition or subtraction of signals captured by two identical transducers which are symmetrically coupled on both sides of the plate. Subsequently, the S0 mode at a non-dispersive frequency bandwidth is employed to improve the accuracy of the transmitter-receiver distance. Based on those, three selection criteria including mode separability, amplitude ratio and corrosion sensitivity, are presented to efficiently determine the suitable operation points (i.e., mode types and frequencies). The experimental results show that the simulated corrosion could be correctly detected and accurately localized at the chosen modes and frequencies.

  6. A pharmaceutical product as corrosion inhibitor for carbon steel in acidic environments.

    PubMed

    Samide, Adriana

    2013-01-01

    A pharmaceutical product, Trimethoprim (TMP), IUPAC name: 5-(3,4,5-trimethoxybenzyl)pyrimidine-2,4-diamine was investigated, as inhibitor to prevent carbon steel corrosion in acidic environments. The study was performed using weight loss and electrochemical measurements, in temperatures ranging between 25-55°C. The surface morphology before and after corrosion of carbon steel in 1.0 M HCl solution in the presence and absence of TMP was evaluated using scanning electron microscopy (SEM). The inhibition efficiency (IE) increased with the increasing of the inhibitor concentration, reaching a maximum value of 92% at 25°C and 0.9 mM TMP, and decreased with increasing temperature. The inhibition of carbon steel corrosion by TMP can be attributed to the adsorption ability of inhibitor molecules onto the reactive sites of the metal surface. The adsorption is spontaneous and it is best described by the Langmuir isotherm. The apparent activation energy (E(a)) for the corrosion process in the absence and presence of TMP was evaluated from Arrhenius equation, to elucidate its inhibitive properties.

  7. Mössbauer effect study of corrosion processes at iron surfaces

    NASA Astrophysics Data System (ADS)

    Ching Lin, Mou; Barnes, R. G.; Furtak, T. E.

    1982-05-01

    Mössbauer spectroscopy coupled with electrochemical measurements has been used to study in situ the effects of chloride ions on a passivated iron surface in boric acid-sodium borate buffer solution at a pH of 8.4. The Mössbauer spectrum of the oxide film formed after breakdown of the passive film by aggressive chloride ions consists of a doublet with line-width of 0.51±0.03 mm/sec, isomer shift of 0.35±0.02 mm/sec relative to the metallic iron, and quadrupole splitting of 0.79±0.01 mm/sec. The quadrupole splitting differs from that of the passive film in which it is 0.94±0.06 mm/sec with line-widths of 0.55±0.08 mm/sec, and an isomer shift of 0.36±0.01 mm/sec. However, these parameters are essentially the same as those of the dried passive film and correlate well with those of superparamagnetic γ-Fe2O3. The Mössbauer spectra of oxide films grown in chloride-containing solution and of films exposed to the air for several days are similar to those of films after chemical breakdown. The introduction of chloride ions appear to stabilize the formation of γ-Fe2O3 and to exclude the incorporation of water and formation of di-oxy or di-hydroxy bridging bonds which are crucial to the passivity of the iron surface.

  8. Stainless steel corrosion scale formed in reclaimed water: Characteristics, model for scale growth and metal element release.

    PubMed

    Cui, Yong; Liu, Shuming; Smith, Kate; Hu, Hongying; Tang, Fusheng; Li, Yuhong; Yu, Kanghua

    2016-10-01

    Stainless steels generally have extremely good corrosion resistance, but are still susceptible to pitting corrosion. As a result, corrosion scales can form on the surface of stainless steel after extended exposure to aggressive aqueous environments. Corrosion scales play an important role in affecting water quality. These research results showed that interior regions of stainless steel corrosion scales have a high percentage of chromium phases. We reveal the morphology, micro-structure and physicochemical characteristics of stainless steel corrosion scales. Stainless steel corrosion scale is identified as a podiform chromite deposit according to these characteristics, which is unlike deposit formed during iron corrosion. A conceptual model to explain the formation and growth of stainless steel corrosion scale is proposed based on its composition and structure. The scale growth process involves pitting corrosion on the stainless steel surface and the consecutive generation and homogeneous deposition of corrosion products, which is governed by a series of chemical and electrochemical reactions. This model shows the role of corrosion scales in the mechanism of iron and chromium release from pitting corroded stainless steel materials. The formation of corrosion scale is strongly related to water quality parameters. The presence of HClO results in higher ferric content inside the scales. Cl(-) and SO4(2-) ions in reclaimed water play an important role in corrosion pitting of stainless steel and promote the formation of scales.

  9. 76 FR 20954 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-14

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea..., the Department published in the Federal Register the countervailing duty order on...

  10. 75 FR 18153 - Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-09

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea..., the Department published in the Federal Register the countervailing duty order on...

  11. 77 FR 67395 - Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Revised Schedule for the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-09

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Revised Schedule for the Subject Reviews AGENCY: United States International Trade Commission. ACTION: Notice. DATES:...

  12. 77 FR 16810 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-22

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea..., the Department published in the Federal Register the countervailing duty order on...

  13. Characterization of corrosion products on a copper-containing intrauterine device during storage at room temperature.

    PubMed

    Bastidas, J M; Simancas, J

    1997-02-01

    This paper studies the characterization of corrosion products formed on corroded and uncorroded copper-containing intrauterine devices stored at room temperature for a period of 30 months. The experimental techniques used were X-ray photo-electron spectroscopy and Auger electron spectroscopy. The compounds found were cuprite (Cu2O) and tenorite (CuO). The latter was the main compound formed on corroded samples, forming thin tarnish films.

  14. Influence of benzimidazole derivatives on corrosion and electrochemical behavior of iron

    SciTech Connect

    Makovei, G.L.; Keris, L.D.; Kurmakova, I.N.

    1986-03-01

    The authors study the relation of the ..pi..-electron density of the molecules of benzimidazole and its derivatives and their inhibiting effect in hydrochloric acid. The compositions of the derivatives of synthesized benzimidazole were verified by ultimate analysis and IR spectroscopy. The ..pi..-electron densities were calculated on a computer. It was found that the introduction of a proton increases the charge re-distribution in the imidazole and benzene rings, with practically no change in the charge on the substituents. The efficiency of inhibition of corrosion was studied by the gravimetric and potentiodynamic methods. To elucidate the limiting stages of cathodic evolution of hydrogen and anodic solution of the metal, the authors recorded polarization curves for steel St3 without additive and with 20 mM benzimidazole, 1-(alpha-acetoxy)ethylbensimidazole and 1-acetylbenzimidazole. The polarization curves for various concentrations of benzimidazole and its derivatives in the pH range 0-2 and a calculation of the characteristics of the cathodic evolution of hydrogen suggest that the limiting stage of the process is delayed discharge.

  15. Persistence of commercial nanoscaled zero-valent iron (nZVI) and by-products

    NASA Astrophysics Data System (ADS)

    Adeleye, Adeyemi S.; Keller, Arturo A.; Miller, Robert J.; Lenihan, Hunter S.

    2013-01-01

    The use of nanoscale zero-valent iron (nZVI) for in situ remediation of a wide scale of environmental pollutants is increasing. Bench and field pilot studies have recorded successful cleanup of many pollutants using nZVI and other iron-mediated nanoparticles. However, a major question remains unanswered: what is the long-term environmental fate of the iron nanoparticles used for remediation? We aged three types of commercial nZVI in different aqueous media, including a groundwater sample, under aerobic and anaerobic conditions for 28 days, and found that the bulk of the nZVI injected into polluted sites will end up in the sediment phase of the aquifer. This is mainly due to aggregation-induced sedimentation of the nZVI and the insoluble iron oxides formed when nZVI undergoes corrosion. Iron concentrations >500 g/kg were detected in sediment, a loading level of iron that may potentially affect some organisms and also reduce the permeability of aquifers. Dissolved and suspended iron concentrations initially surged when nZVI was applied, but iron decreased steadily in the supernatant and suspended sediment as the bulk of the iron partitioned into the sediment. Solution and surface chemistry of the iron species showed that nZVI remains reactive for more than 1 month, and that the reactivity of iron and its transformations are governed by environmental factors, including the presence of different ions, ionic strength, natural organic matter, and pH.

  16. Galactic restrictions on iron production by various types of supernovae

    NASA Astrophysics Data System (ADS)

    Acharova, I. A.; Mishurov, Yu. N.; Kovtyukh, V. V.

    2012-02-01

    We propose a statistical method for decomposition of contributions to iron production from various sources: Type II supernovae and the subpopulations of Type Ia supernovae, prompt (their progenitors are short-lived stars with ages lower than ˜100 Myr) and tardy (their progenitors are long-lived stars with ages >100 Myr). To do that, we develop a theory of oxygen and iron synthesis that takes into account the influence of the spiral arms on the amount of the above elements synthesized by both Type II supernovae and prompt Type Ia supernovae. In the framework of the theory, we processed statistically the new, more precise, observational data on Cepheid abundances, which, as is well known, demonstrate non-trivial radial distributions of oxygen and iron in the Galactic disc with bends in the gradients. In our opinion, such fine structure in the distribution of elements along the Galactic disc enables one to decompose the amount of iron unambiguously into three components produced by the above three sources. In addition, by means of our statistical methods we solve this task without any preliminary suppositions about the ratios between the proportions of iron synthesized by the above sources. The total mass supplied to the Galactic disc during its life by all types of supernovae is ˜(4.0 ± 0.4) × 107 M⊙, while the mass of iron occurring in the present interstellar medium (ISM) is ˜(1.20 ± 0.05) × 107 M⊙, i.e. about two thirds of iron is contained in stars and stellar remnants. The relative proportion of iron synthesized by tardy type Ia supernovae for the lifetime of the Galaxy is ˜35 per cent (in the present ISM this portion is ˜50 per cent). Correspondingly, the total proportion of iron supplied to the disc by Type II supernovae and prompt Type Ia supernovae is ˜65 per cent (in the present ISM this proportion is ˜50 per cent). The above result depends slightly on the adopted mass of oxygen and iron synthesized during one supernova explosion and the

  17. Dictionary of corrosion and corrosion control: English-German/German-English

    SciTech Connect

    Gross, H.

    1985-01-01

    This dictionary has been complied by coworkers of the Department of Applied Linguistics of the Dresden University of Technology. It comprises the special terms of a highly important economical branch of science and technology. Corrosion-induced damage occurs in every branch of technology, and subsequent losses in money and material are enormous. Experts estimate that about one-third of the annual world production of steel and iron is destroyed by corrosion. Corrosion protection is thus becoming increasingly important in order to solve the problems involved, a profound understanding of corrosion processes and of the possibilities of corrosion control is indispensible. The dictionary comprises approximately 3,000 entries in each part taken from a wide variety of fields.

  18. [Using Raman spectrum analysis to research corrosive productions occurring in alloy of ancient bronze wares].

    PubMed

    Jia, La-jiang; Jin, Pu-jun

    2015-01-01

    The present paper analyzes the interior rust that occurred in bronze alloy sample from 24 pieces of Early Qin bronze wares. Firstly, samples were processed by grinding, polishing and ultrasonic cleaning-to make a mirror surface. Then, a confocal micro-Raman spectrometer was employed to carry out spectroscopic study on the inclusions in samples. The conclusion indicated that corrosive phases are PbCO3 , PbO and Cu2O, which are common rusting production on bronze alloy. The light-colored circular or massive irregular areas in metallographic structure of samples are proved as Cu2O, showing that bronze wares are not only easy to be covered with red Cu2O rusting layer, but also their alloy is easy to be eroded by atomic oxygen. In other words, the rust Cu2O takes place in both the interior and exterior parts of the bronze alloy. In addition, Raman spectrum analysis shows that the dark grey materials are lead corrosive products--PbCO3 and PbO, showing the corroding process of lead element as Pb -->PbO-->PbCO3. In the texture of cast state of bronze alloy, lead is usually distributed as independent particles between the different alloy phases. The lead particles in bronze alloy would have oxidation reaction and generate PbO when buried in the soil, and then have chemical reaction with CO3(2-) dissolved in the underground water to generate PbCO3, which is a rather stable lead corrosive production. A conclusion can be drawn that the external corrosive factors (water, dissolved oxygen and carbonate, etc) can enter the bronze ware interior through the passageway between different phases and make the alloy to corrode gradually.

  19. Siderophore production in high iron environments

    NASA Astrophysics Data System (ADS)

    Bennett, S. A.; Hoffman, C. L.; Moffett, J. W.; Edwards, K. J.

    2010-12-01

    Up until recently, the geochemical cycling of Fe in deep sea hydrothermal plumes has assumed to be inorganically dominated, resulting in quantitative precipitation of all hydrothermally sourced Fe to the seafloor. Recent detection of organic Fe binding ligands within both the dissolved and particulate phase (Bennett et al., 2008; Toner et al., 2009), suggests that hydrothermally sourced Fe may be important on a global scale (Tagliabue et al., 2010). The source of these organic ligands is currently unknown; hypotheses include the possible entrainment of organic carbon from the biologically rich diffuse flow areas, or in-situ production from microbial processes. However, the microbial production of organic ligands is only expected when Fe is a limited micronutrient, which is not the case in the hydrothermal environment. The importance of Fe cycling microorganisms within hydrothermal systems was previously overlooked due to the poor energetics with regards to Fe oxidation and reduction. But their recent detection within the hydrothermal system, both around low temperature Fe rich mineral deposits and within hydrothermal plumes (Edwards et al., 2004; Sylvan et al., In prep) suggests that they may have an important role in the hydrothermal Fe cycle, potentially resulting in an interplay between Fe and organic carbon. Within the laboratory, we have carried out experiments to investigate an Fe oxidizing bacteria in a variety of high Fe environments. We have detected both the production of siderophores and an increase in reduced Fe when the Fe oxidizing bacteria is exposed to both Fe(III) and Fe(II) rich minerals. The role of these microbes in the mineral dissolution of Fe sulfides along the seafloor and within the hydrothermal plume, may have important implications on the speciation of Fe and the role of siderophores in the marine environment. Bennett, S.A. et al. 2008. EPSL, 270: 157-167. Edwards, K.J. et al. 2004. Geomicrobiology Journal, 21: 393-404. Sylvan, J.B. et al

  20. High-temperature oxidation/corrosion of iron-based superalloys

    NASA Technical Reports Server (NTRS)

    Lemkey, F. D.; Smeggil, J. G.; Bailey, R. S.; Schuster, J. C.; Nowotny, H.

    1987-01-01

    The oxidation and sulfidation of several novel iron-base superalloys were evaluated in high-temperature cyclic tests. The experimental austenitic alloys examined were modifications of NASAUT-4GA which were developed for Stirling-engine application. The weight gains and resulting surface scales were measured and analyzed. Mixed oxide scales were found to form on all specimens exposed above 871 C. The build-up of these scales led to a depletion of Mn and Cr in a zone adjacent to the oxides. In addition, the initial oxidation of the Fe-rich alloy was inhibited by a thin but tenacious Si layer which formed at the interface between oxides and the parent layer. Sulfidation tests using Na2SO4 coatings resulted in the formation of a protective spinel and alpha-Fe2O3 phases. Preferential attack of the carbide phase by hydrogen was not observed after 350 h at 871 C.

  1. Testing and prediction of erosion-corrosion for corrosion resistant alloys used in the oil and gas production industry

    NASA Astrophysics Data System (ADS)

    Rincon, Hernan E.

    The corrosion behavior of CRAs has been thoroughly investigated and documented in the public literature by many researchers; however, little work has been done to investigate erosion-corrosion of such alloys. When sand particles are entrained in the flow, the degradation mechanism is different from that observed for sand-free corrosive environment. There is a need in the oil and gas industry to define safe service limits for utilization of such materials. The effects of flow conditions, sand rate, pH and temperature on the erosion-corrosion of CRAs were widely studied. An extensive experimental work was conducted using scratch tests and flow loop tests using several experimental techniques. At high erosivity conditions, a synergistic effect between erosion and corrosion was observed. Under the high sand rate conditions tested, erosivity is severe enough to damage the passive layer protecting the CRA thereby enhancing the corrosion rate. In most cases there is likely a competition between the rates of protective film removal due to mechanical erosion and protective film healing. Synergism occurs for each of the three alloys examined (13Cr and Super13Cr and 22Cr); however, the degree of synergism is quite different for the three alloys and may not be significant for 22Cr for field conditions where erosivities are typically much lower that those occurring in the small bore loop used in this research. Predictions of the corrosion component of erosion-corrosion based on scratch test data compared reasonably well to test results from flow loops for the three CRAs at high erosivity conditions. Second order behavior appears to be an appropriate and useful model for representing the repassivation process of CRAs. A framework for a procedure to predict penetration rates for erosion-corrosion conditions was developed based on the second order model behavior observed for the re-healing process of the passive film of CRAs and on computational fluid dynamics (CFD) simulations

  2. Environmental boundary and formation mechanism of different types of H2S corrosion products on pipeline steel

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Li, Hui-xin; Shi, Feng-xian; Yang, Jian-wei; Hu, Li-hua; Lu, Min-xu

    2017-04-01

    To establish an adequate thermodynamic model for the mechanism of formation of hydrogen sulfide (H2S) corrosion products, theoretical and experimental studies were combined in this work. The corrosion products of API X60 pipeline steel formed under different H2S corrosion conditions were analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. A thermodynamic model was developed to clarify the environmental boundaries for the formation and transformation of different products. Presumably, a dividing line with a negative slope existed between mackinawite and pyrrhotite. Using experimental data presented in this study combined with previously published results, we validated the model to predict the formation of mackinawite and pyrrhotite on the basis of the laws of thermodynamics. The established relationship is expected to support the investigation of the H2S corrosion mechanism in the oil and gas industry.

  3. Understanding Passive Layer Formation for Further Corrosion Management in Gas Production Pipes

    NASA Astrophysics Data System (ADS)

    Santoso, R. K.; Rahmawati, S. D.; Gadesa, A.; Wahyuningrum, D.

    2017-07-01

    Corrosion is a critical issue during the development of a gas field, especially wet gas or retrograde gas field. Corrosion affects the management system of a field and further impacts the amount of investment. Therefore, accurate prediction of corrosion rate is needed to plan an effective preventive action before going further to the development phase. One of the important parameters that should be noticed to create an accurate prediction is the formation of the passive layer. In CO2-H2S environment, there will be three possibilities of passive layer: FeS, FeCO3 or no passive layer. In this study, we create mathematical models to determine the formed passive layer in each segment of the gas production tubing and pipeline. The model is built using Faraday’s Law and Thermodynamic approach to account the passive layer formation at different temperature, pH, corrosion rate and partial pressure of CO2 and H2S. From the simulation, it was found that there were three boundary conditions: no scale-FeS boundary, no scale-FeCO3 boundary and FeS-FeCO3 boundary. The first two boundaries evolved over a time as the concentration of Fe2+ ions was increasing. However, FeS-FeCO3 boundary remained steady as it was not affected by the addition of Fe2+ ions. Using sample case study, few variations were noticed at production pipeline and tubing. It was caused by the gas composition, which contained high CO2 and very low H2S. Boundary conditions only changed slightly over two days period.

  4. Environment-induced embrittlement: Stress corrosion cracking and metal-induced embrittlement; Environmental embrittlement of iron aluminide alloys. Final report, September 1, 1986--August 31, 1991

    SciTech Connect

    Heldt, L.A.; Milligan, W.W.; White, C.L.

    1991-12-31

    This research program has included two thrusts. The first addressed environment-induced embrittlement in a parallel study of stress corrosion cracking and metal-induced embrittlement. This work has examined (1) mechanical properties as influenced by embrittling environments, (2) fractography and crystallography or transgranular cracking, (3) the mechanics of cracking, (4) the extent and role of local plastic flow, and (5) local chemistry within stress corrosion and metal-induced cracks. The embrittlement of iron aluminide alloys by air was addressed by determining the effect of water and hydrogen upon the mechanical properties. Slow strain rate testing in aqueous environments was carried out at controlled anodic and cathodic potentials. The effect of cathodically charged hydrogen and the effect of subsequent baking were measured. Environmental susceptibility was measured as affected by alloy composition, microstructure and degree of ordering.

  5. Iron

    MedlinePlus

    Iron is a mineral that our bodies need for many functions. For example, iron is part of hemoglobin, a protein which carries ... It helps our muscles store and use oxygen. Iron is also part of many other proteins and ...

  6. Metabolomic and Metagenomic Analysis of Two Crude Oil Production Pipelines Experiencing Differential Rates of Corrosion

    PubMed Central

    Bonifay, Vincent; Wawrik, Boris; Sunner, Jan; Snodgrass, Emily C.; Aydin, Egemen; Duncan, Kathleen E.; Callaghan, Amy V.; Oldham, Athenia; Liengen, Turid; Beech, Iwona

    2017-01-01

    Corrosion processes in two North Sea oil production pipelines were studied by analyzing pig envelope samples via metagenomic and metabolomic techniques. Both production systems have similar physico-chemical properties and injection waters are treated with nitrate, but one pipeline experiences severe corrosion and the other does not. Early and late pigging material was collected to gain insight into the potential causes for differential corrosion rates. Metabolites were extracted and analyzed via ultra-high performance liquid chromatography/high-resolution mass spectrometry with electrospray ionization (ESI) in both positive and negative ion modes. Metabolites were analyzed by comparison with standards indicative of aerobic and anaerobic hydrocarbon metabolism and by comparison to predicted masses for KEGG metabolites. Microbial community structure was analyzed via 16S rRNA gene qPCR, sequencing of 16S PCR products, and MySeq Illumina shotgun sequencing of community DNA. Metagenomic data were used to reconstruct the full length 16S rRNA genes and genomes of dominant microorganisms. Sequence data were also interrogated via KEGG annotation and for the presence of genes related to terminal electron accepting (TEA) processes as well as aerobic and anaerobic hydrocarbon degradation. Significant and distinct differences were observed when comparing the ‘high corrosion’ (HC) and the ‘low corrosion’ (LC) pipeline systems, especially with respect to the TEA utilization potential. The HC samples were dominated by sulfate-reducing bacteria (SRB) and archaea known for their ability to utilize simple carbon substrates, whereas LC samples were dominated by pseudomonads with the genetic potential for denitrification and aerobic hydrocarbon degradation. The frequency of aerobic hydrocarbon degradation genes was low in the HC system, and anaerobic hydrocarbon degradation genes were not detected in either pipeline. This is in contrast with metabolite analysis, which

  7. Effect of zinc, copper, and iron on ochratoxin A production.

    PubMed

    Steele, J A; Davis, N D; Diener, U L

    1973-05-01

    The effect of zinc, copper, and iron levels on production of ochratoxin A by Aspergillus ochraceus Wilhelm in a synthetic medium in a shake culture was investigated. Optimal concentrations of ZnSO(4), CuSO(4), and FeCl(3) for ochratoxin A production were 0.055 to 2.2 mg/liter, 0.004 to 0.04 mg/liter, and 1.2 to 24 mg/liter, respectively. Zinc and copper levels greater than optimum reduced the rate of ochratoxin accumulation without altering either glutamate or sucrose utilization. Ochratoxin A production was correlated with rapid utilization of sucrose by the fungus and decreasing pH of the medium. Most of the glutamic acid was removed from the medium prior to ochratoxin production. There was no correlation between mycelial dry weight and ochratoxin A production.

  8. Effect of Zinc, Copper, and Iron on Ochratoxin A Production

    PubMed Central

    Steele, J. A.; Davis, N. D.; Diener, U. L.

    1973-01-01

    The effect of zinc, copper, and iron levels on production of ochratoxin A by Aspergillus ochraceus Wilhelm in a synthetic medium in a shake culture was investigated. Optimal concentrations of ZnSO4, CuSO4, and FeCl3 for ochratoxin A production were 0.055 to 2.2 mg/liter, 0.004 to 0.04 mg/liter, and 1.2 to 24 mg/liter, respectively. Zinc and copper levels greater than optimum reduced the rate of ochratoxin accumulation without altering either glutamate or sucrose utilization. Ochratoxin A production was correlated with rapid utilization of sucrose by the fungus and decreasing pH of the medium. Most of the glutamic acid was removed from the medium prior to ochratoxin production. There was no correlation between mycelial dry weight and ochratoxin A production. PMID:4715563

  9. Magnesium and iron nanoparticles production using microorganisms and various salts

    NASA Astrophysics Data System (ADS)

    Kaul, R. K.; Kumar, P.; Burman, U.; Joshi, P.; Agrawal, A.; Raliya, R.; Tarafdar, J. C.

    2012-09-01

    Response of five fungi and two bacteria to different salts of magnesium and iron for production of nanoparticles was studied. Pochonia chlamydosporium, and Aspergillus fumigatus were exposed to three salts of magnesium while Curvularia lunata, Chaetomium globosum, A. fumigatus, A. wentii and the bacteria Alcaligenes faecalis and Bacillus coagulans were exposed to two salts of iron for nanoparticle production. The results revealed that P. chlamydosporium induces development of extracellular nanoparticles in MgCl2 solution while A. fumigatus produces also intracellular nanoparticles when exposed to MgSO4 solution. C. globosum was found as the most effective in producing nanoparticles when exposed to Fe2O3 solution. The FTIR analysis of the nanoparticles obtained from Fe2O3 solution showed the peaks similar to iron (Fe). In general, the species of the tested microbes were selective to different chemicals in their response for synthesis of nanoparticles. Further studies on their characterization and improving the efficiency of promising species of fungi need to be undertaken before tapping their potential as nanonutrients for plants.

  10. ARSENATE AND ARSENITE SORPTION AND ARSENITE OXIDATION BY IRON (II, III) HYDROXYCARBONATE GREEN RUST

    EPA Science Inventory

    Iron (II, III) hydroxycarbonate green rust is a major corrosion product of zerovalent iron that is being used in permeable reactive barriers to remediate groundwater arsenic contamination. To optimize the design of iron barriers, it is important to evaluate the influence of geoch...

  11. ARSENATE AND ARSENITE SORPTION AND ARSENITE OXIDATION BY IRON (II, III) HYDROXYCARBONATE GREEN RUST

    EPA Science Inventory

    Iron (II, III) hydroxycarbonate green rust is a major corrosion product of zerovalent iron that is being used in permeable reactive barriers to remediate groundwater arsenic contamination. To optimize the design of iron barriers, it is important to evaluate the influence of geoch...

  12. CHEMICAL INTERACTIONS OF ARSENATE, ARSENITE, PHOSPHATE, AND SILICATE WITH IRON (II, III) HYDROXYCARBONATE GREEN RUST

    EPA Science Inventory

    Granular zerovalent iron has been proposed to be used as a medium in permeable reactive barriers (PRBs) to remove arsenic from contaminated groundwater. Iron(II, III) hydroxycarbonate green rust (carbonate green rust, or CGR) is a major corrosion product of zerovalent iron under ...

  13. CHEMICAL INTERACTIONS OF ARSENATE, ARSENITE, PHOSPHATE, AND SILICATE WITH IRON (II,III) HYDROXYCARBONATE GREEN RUST

    EPA Science Inventory

    Granular zerovalent iron has been proposed to be used as a medium in permeable reactive barriers (PRBs) to remove arsenic from contaminated groundwater. Iron(II, III) hydroxycarbonate green rust (carbonate green rust, or CGR) is a major corrosion product of zerovalent iron under ...

  14. CHEMICAL INTERACTIONS OF ARSENATE, ARSENITE, PHOSPHATE, AND SILICATE WITH IRON (II,III) HYDROXYCARBONATE GREEN RUST

    EPA Science Inventory

    Granular zerovalent iron has been proposed to be used as a medium in permeable reactive barriers (PRBs) to remove arsenic from contaminated groundwater. Iron(II, III) hydroxycarbonate green rust (carbonate green rust, or CGR) is a major corrosion product of zerovalent iron under ...

  15. CHEMICAL INTERACTIONS OF ARSENATE, ARSENITE, PHOSPHATE, AND SILICATE WITH IRON (II, III) HYDROXYCARBONATE GREEN RUST

    EPA Science Inventory

    Granular zerovalent iron has been proposed to be used as a medium in permeable reactive barriers (PRBs) to remove arsenic from contaminated groundwater. Iron(II, III) hydroxycarbonate green rust (carbonate green rust, or CGR) is a major corrosion product of zerovalent iron under ...

  16. FY05 HPCRM Annual Report: High-Performance Corrosion-Resistant Iron-Based Amorphous Metal Coatings Evaluation of Corrosion Reistance FY05 HPCRM Annual Report # Rev. 1DOE-DARPA Co-Sponsored Advanced Materials Program

    SciTech Connect

    Farmer, J C; Haslam, J J; Day, S D

    2007-09-19

    New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Two Fe-based amorphous metal formulations have been found that appear to have corrosion resistance comparable to, or better than that of Ni-based Alloy C-22, based on breakdown potential and corrosion rate. Both Cr and Mo provide corrosion resistance, B enables glass formation, and Y lowers critical cooling rate (CCR). SAM1651 has yttrium added, and has a nominal critical cooling rate of only 80 Kelvin per second, while SAM2X7 (similar to SAM2X5) has no yttrium, and a relatively high critical cooling rate of 610 Kelvin per second. Both amorphous metal formulations have strengths and weaknesses. SAM1651 (yttrium added) has a low critical cooling rate (CCR), which enables it to be rendered as a completely amorphous thermal spray coating. Unfortunately, it is relatively difficult to atomize, with powders being irregular in shape. This causes the powder to be difficult to pneumatically convey during thermal spray deposition. Gas atomized SAM1651 powder has required cryogenic milling to eliminate irregularities that make flow difficult. SAM2X5 (no yttrium) has a high critical cooling rate, which has caused problems associated with devitrification. SAM2X5 can be gas atomized to produce spherical powders of SAM2X5, which enable more facile thermal spray deposition. The reference material, nickel-based Alloy C-22, is an outstanding corrosion-resistant engineering material. Even so, crevice corrosion has been observed with C-22 in hot sodium chloride environments without buffer

  17. Analysis of the magnetic corrosion product deposits on a boiling water reactor cladding

    SciTech Connect

    Orlov, Andrey; Degueldre, Claude; Kaufmann, Wilfried

    2013-01-15

    The buildup of corrosion product deposits (CRUD) on the fuel cladding of the boiling water reactor (BWR) before and after zinc injection has been investigated by applying local experimental analytical techniques. Under the BWR water chemistry conditions, Zn addition together with the presence of Ni and Mn induce the formation of (Zn,Ni,Mn)[Fe{sub 2}O{sub 4}] spinel solid solutions. X-ray absorption spectroscopy (XAS) revealed inversion ratios of cation distribution in spinels deposited from the solid solution. Based on this information, a two-site ferrite spinel solid solution model is proposed. Electron probe microanalysis (EPMA) and extended X-ray absorption fine structure (EXAFS) findings suggest the zinc-rich ferrite spinels formation on BWR fuel cladding mainly at lower pin. - Graphical Abstract: Analysis of spinels in corrosion product deposits on boiling water reactor fuel rod. Combining EPMA and XAFS results: schematic representation of the ferrite spinels in terms of the end members and their extent of inversion. Note that the ferrites are represented as a surface between the normal (upper plane, M[Fe{sub 2}]O{sub 4}) and the inverse (lower plane, Fe[MFe]O{sub 4}). Actual compositions red Black-Small-Square for the specimen at low elevation (810 mm), blue Black-Small-Square for the specimen at mid elevation (1800 mm). The results have an impact on the properties of the CRUD material. Highlights: Black-Right-Pointing-Pointer Buildup of corrosion product deposits on fuel claddings of a boiling water reactor (BWR) are investigated. Black-Right-Pointing-Pointer Under BWR water conditions, Zn addition with Ni and Mn induced formation of (Zn,Ni,Mn)[Fe{sub 2}O{sub 4}]. Black-Right-Pointing-Pointer X-Ray Adsorption Spectroscopy (XAS) revealed inversion of cations in spinel solid solutions. Black-Right-Pointing-Pointer Zinc-rich ferrite spinels are formed on BWR fuel cladding mainly at lower pin elevations.

  18. Properties of colloidal corrosion products and their effects on nuclear plants. Final report. [PWR; BWR

    SciTech Connect

    Matijevic, E.

    1982-09-01

    Detailed results from the first two years of work on the properties of corrosion product oxides common to light water nuclear reactor systems are presented. A smaller companion volume describes the results in overview fashion. Numerous methods are described for producing these model oxides in forms making their study simpler, i.e., particles with uniform diameter and composition. A number of studies of particle adhesion to simulated power plant surfaces are described. The magnetic properties of hematite of various particle sizes are described - a property important to the use of electromagnetic filtration in LWRs.

  19. Iron-catalyzed hydrogen production from formic acid.

    PubMed

    Boddien, Albert; Loges, Björn; Gärtner, Felix; Torborg, Christian; Fumino, Koichi; Junge, Henrik; Ludwig, Ralf; Beller, Matthias

    2010-07-07

    Hydrogen represents a clean energy source, which can be efficiently used in fuel cells generating electricity with water as the only byproduct. However, hydrogen generation from renewables under mild conditions and efficient hydrogen storage in a safe and reversible manner constitute important challenges. In this respect formic acid (HCO(2)H) represents a convenient hydrogen storage material, because it is one of the major products from biomass and can undergo selective decomposition to hydrogen and carbon dioxide in the presence of suitable catalysts. Here, the first light-driven iron-based catalytic system for hydrogen generation from formic acid is reported. By application of a catalyst formed in situ from inexpensive Fe(3)(CO)(12), 2,2':6'2''-terpyridine or 1,10-phenanthroline, and triphenylphosphine, hydrogen generation is possible under visible light irradiation and ambient temperature. Depending on the kind of N-ligands significant catalyst turnover numbers (>100) and turnover frequencies (up to 200 h(-1)) are observed, which are the highest known to date for nonprecious metal catalyzed hydrogen generation from formic acid. NMR, IR studies, and DFT calculations of iron complexes, which are formed under reaction conditions, confirm that PPh(3) plays an active role in the catalytic cycle and that N-ligands enhance the stability of the system. It is shown that the reaction mechanism includes iron hydride species which are generated exclusively under irradiation with visible light.

  20. Perforation corrosion and its mechanism on galvanized steel sheets on vehicles

    SciTech Connect

    Fujita, Sakae

    1998-12-31

    Mechanism of perforation corrosion on vehicles in the area where deicing salts are dispersed on roads in winter was investigated, using the Gumbel probability plots of the maximum depth of corrosion inside the lapped portion and quantitative analyses of crystalline compositions of the iron rusts which formed on the steel panels of vehicles. It was estimated that perforation occurred in 7 years for zincrometal steel sheet and more than 14 years for galvanized steel sheet with zinc coating weight of 120g/m{sup 2} in the crevice of lapped panel. The composition of the rust in the lapped portion of galvanized steel panels was mainly amorphous at the initial stage of corrosion and moves towards the high content of ({gamma}-FeOOH+Fe{sub 3}O{sub 4}) regions of the non-galvanized parts. Zinc corrosion product prevented the redox reaction of the iron rust and performed as corrosion inhibitor of steel in laboratory simulation tests. Perforation mechanism on vehicles in real environments will be also discussed in the following stages; (1) corrosion of zinc layer, (2) galvanic corrosion of zinc, (3) corrosion of steel under zinc corrosion product, (4) corrosion of steel.

  1. Corrosion resistance of stainless steels during thermal cycling in alkali nitrate molten salts.

    SciTech Connect

    Bradshaw, Robert W.; Goods, Steven Howard

    2001-09-01

    The corrosion behavior of three austenitic stainless steels was evaluated during thermal cycling in molten salt mixtures consisting of NaNO{sub 3} and KNO{sub 3}. Corrosion tests were conducted with Types 316, 316L and 304 stainless steels for more than 4000 hours and 500 thermal cycles at a maximum temperature of 565 C. Corrosion rates were determined by chemically descaling coupons. Metal losses ranged from 5 to 16 microns and thermal cycling resulted in moderately higher corrosion rates compared to isothermal conditions. Type 316 SS was somewhat more corrosion resistant than Type 304 SS in these tests. The effect of carbon content on corrosion resistance was small, as 316L SS corroded only slightly slower than 316 SS. The corrosion rates increased as the dissolved chloride content of the molten salt mixtures increased. Chloride concentrations approximating 1 wt.%, coupled with thermal cycling, resulted in linear weight loss kinetics, rather than parabolic kinetics, which described corrosion rates for all other conditions. Optical microscopy and electron microprobe analysis revealed that the corrosion products consisted of iron-chromium spinel, magnetite, and sodium ferrite, organized as separate layers. Microanalysis of the elemental composition of the corrosion products further demonstrated that the chromium content of the iron-chromium spinel layer was relatively high for conditions in which parabolic kinetics were observed. However, linear kinetics were observed when the spinel layer contained relatively little chromium.

  2. Metallic corrosion in the polluted urban atmosphere of Hong Kong.

    PubMed

    Liu, Bo; Wang, Da-Wei; Guo, Hai; Ling, Zhen-Hao; Cheung, Kalam

    2015-01-01

    This study aimed to explore the relationship between air pollutants, particularly acidic particles, and metallic material corrosion. An atmospheric corrosion test was carried out in spring-summer 2012 at a polluted urban site, i.e., Tung Chung in western Hong Kong. Nine types of metallic materials, namely iron, Q235 steel, 20# steel, 16Mn steel, copper, bronze, brass, aluminum, and aluminum alloy, were selected as specimens for corrosion tests. Ten sets of the nine materials were all exposed to ambient air, and then each set was collected individually after exposure to ambient air for consecutive 6, 13, 20, 27, 35, 42, 49, 56, 63, and 70 days, respectively. After the removal of the corrosion products on the surface of the exposed specimens, the corrosion rate of each material was determined. The surface structure of materials was observed using scanning electron microscopy (SEM) before and after the corrosion tests. Environmental factors including temperature, relative humidity, concentrations of gaseous pollutants, i.e., sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), ozone (O₃), and particulate-phase pollutants, i.e., PM₂.₅ (FSP) and PM₁₀ (RSP), were monitored. Correlation analysis between environmental factors and corrosion rate of materials indicated that iron and carbon steel were damaged by both gaseous pollutants (SO₂ and NO₂) and particles. Copper and copper alloys were mainly corroded by gaseous pollutants (SO₂ and O₃), while corrosion of aluminum and aluminum alloy was mainly attributed to NO₂ and particles.

  3. Use of Bacteria To Stabilize Archaeological Iron.

    PubMed

    Comensoli, Lucrezia; Maillard, Julien; Albini, Monica; Sandoz, Frederic; Junier, Pilar; Joseph, Edith

    2017-05-01

    Iron artifacts are common among the findings of archaeological excavations. The corrosion layer formed on these objects requires stabilization after their recovery, without which the destruction of the item due to physicochemical damage is likely. Current technologies for stabilizing the corrosion layer are lengthy and generate hazardous waste products. Therefore, there is a pressing need for an alternative method for stabilizing the corrosion layer on iron objects. The aim of this study was to evaluate an alternative conservation-restoration method using bacteria. For this, anaerobic iron reduction leading to the formation of stable iron minerals in the presence of chlorine was investigated for two strains of Desulfitobacterium hafniense (strains TCE1 and LBE). Iron reduction was observed for soluble Fe(III) phases as well as for akaganeite, the most troublesome iron compound in the corrosion layer of archaeological iron objects. In terms of biogenic mineral production, differential efficiencies were observed in assays performed on corroded iron coupons. Strain TCE1 produced a homogeneous layer of vivianite covering 80% of the corroded surface, while on the coupons treated with strain LBE, only 10% of the surface was covered by the same mineral. Finally, an attempt to reduce iron on archaeological objects was performed with strain TCE1, which led to the formation of both biogenic vivianite and magnetite on the surface of the artifacts. These results demonstrate the potential of this biological treatment for stabilizing archaeological iron as a promising alternative to traditional conservation-restoration methods.IMPORTANCE Since the Iron Age, iron has been a fundamental material for the building of objects used in everyday life. However, due to its reactivity, iron can be easily corroded, and the physical stability of the object built is at risk. This is particularly true for archaeological objects on which a potentially unstable corrosion layer is formed during

  4. Development of an Accelerated Test Method for the Determination of Susceptibility to Atmospheric Corrosion

    NASA Technical Reports Server (NTRS)

    Ambrose, John R.

    1991-01-01

    The theoretical rationale is presented for use of a repetitive cyclic current reversal voltammetric technique for characterization of localized corrosion processes, including atmospheric corrosion. Applicability of this proposed experimental protocol is applied to characterization of susceptibility to crevice and pitting corrosion, atmospheric corrosion and stress corrosion cracking. Criteria upon which relative susceptibility is based were determined and tested using two iron based alloys commonly in use at NASA-Kennedy; A36 (a low carbon steel) and 4130 (a low alloy steel). Practicality of the procedure was demonstrated by measuring changes in anodic polarization behavior during high frequency current reversal cycles of 25 cycles per second with 1 mA/sq cm current density amplitude in solutions containing Cl anions. The results demonstrated that, due to excessive polarization which affects conductivity of barrier corrosion product layers, A36 was less resistant to atmospheric corrosion than its 4130 counterpart; behavior which was also demonstrated during exposure tests.

  5. Comparison of microbial communities involved in souring and corrosion in offshore and onshore oil production facilities in Nigeria.

    PubMed

    Okoro, Chuma; Smith, Seun; Chiejina, Leo; Lumactud, Rhea; An, Dongshan; Park, Hyung Soo; Voordouw, Johanna; Lomans, Bart P; Voordouw, Gerrit

    2014-04-01

    Samples were obtained from the Obigbo field, located onshore in the Niger delta, Nigeria, from which oil is produced by injection of low-sulfate groundwater, as well as from the offshore Bonga field from which oil is produced by injection of high-sulfate (2,200 ppm) seawater, amended with 45 ppm of calcium nitrate to limit reservoir souring. Despite low concentrations of sulfate (0-7 ppm) and nitrate (0 ppm), sulfate-reducing bacteria (SRB) and heterotrophic nitrate-reducing bacteria (NRB) were present in samples from the Obigbo field. Biologically active deposits (BADs), scraped from corrosion-failed sections of a water- and of an oil-transporting pipeline (both Obigbo), had high counts of SRB and high sulfate and ferrous iron concentrations. Analysis of microbial community composition by pyrosequencing indicated anaerobic, methanogenic hydrocarbon degradation to be a dominant process in all samples from the Obigbo field, including the BADs. Samples from the Bonga field also had significant activity of SRB, as well as of heterotrophic and of sulfide-oxidizing NRB. Microbial community analysis indicated high proportions of potentially thermophilic NRB and near-absence of microbes active in methanogenic hydrocarbon degradation. Anaerobic incubation of Bonga samples with steel coupons gave moderate general corrosion rates of 0.045-0.049 mm/year, whereas near-zero general corrosion rates (0.001-0.002 mm/year) were observed with Obigbo water samples. Hence, methanogens may contribute to corrosion at Obigbo, but the low general corrosion rates cannot explain the reasons for pipeline failures in the Niger delta. A focus of future work should be on understanding the role of BADs in enhancing under-deposit pitting corrosion.

  6. F2-laser-induced micro/nanostructuring and surface modification of iron thin film to realize hydrophobic and corrosion resistant

    NASA Astrophysics Data System (ADS)

    Okoshi, Masayuki; Awaihara, Yuta; Yamashita, Tsugito; Inoue, Narumi

    2014-11-01

    Nanoswellings of 60 nm height and 500 nm diameter on average of an iron thin film deposited on a silica glass substrate at regular intervals of 2.5 µm were fabricated by the irradiation of a 157 nm F2 laser. The F2 laser was focused on the iron thin film by each microsphere made of silica glass of 2.5 µm diameter, which covered the entire surface of the films. The surface of the silica glass substrate underneath the F2-laser-irradiated iron thin film selectively swelled to push up the film. After the laser-induced micro/nanostructuring, the F2 laser was again irradiated onto the entire surface of the periodic micro/nanostructured iron thin film to form an approximately 2-nm-thick Fe3O4 modified layer. As a result, the samples showed hydrophobicity and high corrosion resistance to 3 wt % NaCl aqueous solution (quasi-seawater). No rust was observed on the samples after the immersion test in the quasi-seawater for 24 h.

  7. 77 FR 25141 - Corrosion-Resistant Carbon Steel Flat Products From Germany and South Korea: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-27

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From Germany and South Korea... Germany and South Korea (Korea), pursuant to section 751(c) of the Tariff Act of 1930, as amended (the Act...-Resistant Carbon Steel Flat Products from Germany and South Korea: Adequacy Redetermination...

  8. Anomalously deep and fast failure of copper and bronze under the action of the corrosion products existing on them

    NASA Astrophysics Data System (ADS)

    Pozhidaeva, S. D.; Eliseeva, A. Yu.; Ivanov, A. M.

    2015-12-01

    When the corrosion products on copper and bronze are in close contact with a diluted aqueous solution of hydrochloric acid and atmospheric oxygen, they rapidly transform into effective metal (alloy) oxidizers, which provide rapid and deep metal consumption. The metal can be almost fully consumed in a reasonable technological time provided the accumulated solid phase of the products is periodically removed.

  9. High solubility pathway for the carbon dioxide free production of iron.

    PubMed

    Licht, Stuart; Wang, Baohui

    2010-10-07

    We report a fundamental change in the understanding of iron oxide thermochemistry, opening a facile, new CO(2)-free route to iron production. The resultant process can eliminate a major global source of greenhouse gas emission, producing the staple iron in molten media at high rate and low electrolysis energy.

  10. Iron migration from the anode surface in alumina electrolysis

    NASA Astrophysics Data System (ADS)

    Zhuravleva, Elena N.; Drozdova, Tatiana N.; Ponomareva, Svetlana V.; Kirik, Sergei D.

    2013-01-01

    Corrosion destruction of two-component iron-based alloys used as an anode in high-temperature alumina electrolysis in the melt of NaF/KF/AlF3 electrolyte has been considered. Ni, Si, Cu, Cr, Mn, Al, Ti in the amount of up to 10% have been tested as the dopants to an anode alloys. The composition of the corrosion products has been studied using X-ray diffraction, scanning electron microscopy and electron microprobe analysis. It has been established that the anode corrosion is induced by a surface electrochemical polarization and iron atom oxidation. Iron ions come into an exchange interaction with the fluoride components of the melted electrolyte, producing FeF2. The last interacts with oxyfluoride species transforming into the oxide forms: FeAl2O4, Fe3O4, Fe2O3. Due to the low solubility, the iron oxides are accumulated in the near-electrode sheath. The only small part of iron from anode migrates to cathode that makes an production of high purity aluminum of a real task. The alloy dopants are also subjected to corrosion in accordance with electromotive series resulting corrosion tunnels on the anode surface. The oxides are final compounds which collect in the same area. The corrosion products form an anode shell which is electronic conductor at electrolysis temperature. The electrolysis of alumina occurs beyond the corrosion shell. The rate limiting step in the corrosion is the electrolyte penetration through corrosion shell to the anode surface. The participation of the released oxygen in the corrosion has not been observed.

  11. Factors affecting catalysis of copper corrosion products in NDMA formation from DMA in simulated premise plumbing.

    PubMed

    Zhang, Hong; Andrews, Susan A

    2013-11-01

    This study investigated the effects of corrosion products of copper, a metal commonly employed in household plumbing systems, on N-nitrosodimethylamine (NDMA) formation from a known NDMA precursor, dimethylamine (DMA). Copper-catalyzed NDMA formation increased with increasing copper concentrations, DMA concentrations, alkalinity and hardness, but decreased with increasing natural organic matter (NOM) concentration. pH influenced the speciation of chloramine and the interactions of copper with DMA. The transformation of monochloramine (NH2Cl) to dichloramine and complexation of copper with DMA were involved in elevating the formation of NDMA by copper at pH 7.0. The inhibiting effect of NOM on copper catalysis was attributed to the rapid consumption of NH2Cl by NOM and/or the competitive complexation of NOM with copper to limit the formation of DMA-copper complexes. Hardness ions, as represented by Ca(2+), also competed with copper for binding sites on NOM, thereby weakening the inhibitory effect of NOM on NDMA formation. Common copper corrosion products also participated in these reactions but in different ways. Aqueous copper released from malachite [Cu2CO3(OH)2] was shown to promote NDMA formation while NDMA formation decreased in the presence of CuO, most likely due to the adsorption of DMA.

  12. [On the iron contamination in cocoa and chocolate products (author's transl)].

    PubMed

    Wijsman, J A

    1978-08-18

    The investigation in question deals with the iron contamination in cocoa and chocolate products. Semi finished goods as well as finished products were examined. An average of 29 mg/kg total iron (i.e. ionic + metallic iron) was found in cocoabeans. The iron content of cocoa shells was approximately 10 fold higher. The process of grinding roasted nibs to cocoa-mass (liquor) resulted in a noticeable increase of the quantity of iron to an average amount of 150 mg/kg mass. This process thus produced an increase of the iron content of approximately 75 to as much as 200%. The cocoa powders contained more iron (238 mg/kg) than the cocoa mass, which linked to a reduction of the fat content by pressing and by grinding of the presscake. The quantities of iron observed in commercial samples of cocoa powder from different countries did not show appreciable differences.

  13. Characterization of corrosion products of AB{sub 5}-type hydrogen storage alloys for nickel-metal hydride batteries

    SciTech Connect

    Maurel, F.; Knosp, B.; Backhaus-Ricoult, M.

    2000-01-01

    To better understand the decrease in storage capacity of AB{sub 5}-type alloys in rechargeable Ni/MH batteries undergoing repeated charge/discharge cycles, the corrosion of a MnNi{sub 3.55}Co{sub 0.75}Mn{sub 0.4}Al{sub 0.3} alloy in aqueous KOH electrolyte was studied. The crystal structure, chemical composition, and distribution of corrosion products were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Hollow and filed needles of a mixed rare earth hydroxide Mn(OH){sub 3} were found to cover a continuous nanocrystalline corrosion scale composed of metal (Ni, Co) solid solution, oxide (Ni,Co)O solid solution and rare earth hydroxide, and a Mn-depleted alloy subscale. Corrosion kinetics were measured for three different temperatures. Growth kinetics of the continuous corrosion scale and of the Mm(OH){sub 3} needles obeyed linear and parabolic rate laws, respectively. Models for the corrosion mechanism were developed on the basis of diffusional transport of Mn and OH through the hydroxide needles and subsequent diffusion along grain boundaries through the nanocrystalline scale.

  14. Addition versus radiolytic production effects of hydrogen peroxide on aqueous corrosion of UO 2

    NASA Astrophysics Data System (ADS)

    Corbel, C.; Sattonnay, G.; Guilbert, S.; Garrido, F.; Barthe, M.-F.; Jegou, C.

    2006-01-01

    The effects of hydrogen peroxide, H 2O 2, on UO 2 corrosion is investigated in aerated deionized water in two types of situations. The H 2O 2 species is either added to water or produced by radiolysis at UO 2/H 2O interfaces. The concentrations vary in the range 10 -5-10 -1 mol l -1. The radiolysis is induced by irradiating the UO 2/H 2O interfaces with a He 2+-beam emerging from the UO 2 discs into the solutions. Both the evolution of the aqueous solutions and the UO 2 surfaces are characterised. In both types of experiments, the alteration of UO 2 results in the formation of the same secondary phase, an hydrated uranium peroxide called studtite (UO 2(O) 2 · 4H 2O). However, the uranium release at the interface differs strikingly. It is much higher when H 2O 2 is produced by irradiation than when it is simply added. Furthermore, it varies in opposite direction as a function of the H 2O 2 concentration. This gives evidence that the chemistry at the UO 2 interface under irradiation differs significantly from the chemistry induced by simply adding H 2O 2 to the solution. Rutherford backscattering spectrometry is used to determine the growth rate of the corrosion layer. For H 2O 2 addition, the layer thickness increases with increasing leaching time, although as time increases, the U release tends towards zero. It is possible to establish the first empirical equation relating the corrosion rates to the added H 2O 2 concentrations. For H 2O 2 radiolytic production, the growth is continuous as irradiation time increases but the growth rate seems to decrease as the layer grows and to reach a limit.

  15. Significance of Iron(II,III) Hydroxycarbonate Green Rust in Arsenic Remediation Using Zerovalent Iron in Laboratory Column Tests

    EPA Science Inventory

    We examined the corrosion products of zerovalent iron used in three column tests for removing arsenic from water under dynamic flow conditions. Each column test lasted three- to four-months using columns consisting of a 10.3-cm depth of 50 : 50 (w : w, Peerless iron : sand) in t...

  16. Significance of Iron(II,III) Hydroxycarbonate Green Rust in Arsenic Remediation Using Zerovalent Iron in Laboratory Column Tests

    EPA Science Inventory

    We examined the corrosion products of zerovalent iron used in three column tests for removing arsenic from water under dynamic flow conditions. Each column test lasted three- to four-months using columns consisting of a 10.3-cm depth of 50 : 50 (w : w, Peerless iron : sand) in t...

  17. On corrosivity of sulphate-nitrate-chloride sewage used in catalyst production

    SciTech Connect

    Medvedeva, M.L.

    1995-09-01

    Solutions containing sodium chloride, nitrate, and sulfate are most often used in petroleum processing plants. These solutions are very corrosive to the equipment in the waste processing plants. The corrosivity of the solutions was studied and corrosion resistance was measured as a function of mass loss.

  18. High-Performance Corrosion-Resistant Materials: Iron-Based Amorphous-Metal Thermal-Spray Coatings: SAM HPCRM Program ? FY04 Annual Report ? Rev. 0 - DARPA DSO & DOE OCRWM Co-Sponsored Advanced Materials Program

    SciTech Connect

    Farmer, J; Haslam, J; Wong, F; Ji, S; Day, S; Branagan, D; Marshall, M; Meacham, B; Buffa, E; Blue, C; Rivard, J; Beardsley, M; Buffa, E; Blue, C; Rivard, J; Beardsley, M; Weaver, D; Aprigliano, L; Kohler, L; Bayles, R; Lemieux, E; Wolejsza, T; Martin, F; Yang, N; Lucadamo, G; Perepezko, J; Hildal, K; Kaufman, L; Heuer, A; Ernst, F; Michal, G; Kahn, H; Lavernia, E

    2007-09-19

    The multi-institutional High Performance Corrosion Resistant Materials (HPCRM) Team is cosponsored by the Defense Advanced Projects Agency (DARPA) Defense Science Office (DSO) and the Department of Energy (DOE) Office of Civilian Radioactive Waste Management (OCRWM), and has developed new corrosion-resistant, iron-based amorphous metals that can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Corrosion costs the Department of Defense billions of dollars every year, with an immense quantity of material in various structures undergoing corrosion. For example, in addition to fluid and seawater piping, ballast tanks, and propulsions systems, approximately 345 million square feet of structure aboard naval ships and crafts require costly corrosion control measures. The use of advanced corrosion-resistant materials to prevent the continuous degradation of this massive surface area would be extremely beneficial. The Fe-based corrosion-resistant, amorphous-metal coatings under development may prove of importance for applications on ships. Such coatings could be used as an 'integral drip shield' on spent fuel containers, as well as protective coatings that could be applied over welds, thereby preventing exposure to environments that might cause stress corrosion cracking. In the future, such new high-performance iron-based materials could be substituted for more-expensive nickel-based alloys, thereby enabling a reduction in the $58-billion life cycle cost for the long-term storage of the Nation's spent nuclear fuel by tens of percent.

  19. Protective effect of phytic acid hydrolysis products on iron-induced lipid peroxidation of liposomal membranes.

    PubMed

    Miyamoto, S; Kuwata, G; Imai, M; Nagao, A; Terao, J

    2000-12-01

    Beneficial effects of dietary phytic acid (myo-inositol hexaphosphate; IP6) have often been explained by its strong iron ion-chelating ability, which possibly suppresses iron ion-induced oxidative damage in the gastrointestinal tract. Because phytic acid is hydrolyzed during digestion, this work aimed to know whether its hydrolysis products (IP2, IP3, IP4, and IP5) could still prevent iron ion-induced lipid peroxidation. Studies using liposomal membranes demonstrated that hydrolysis products containing three or more phosphate groups are able to inhibit iron ion-induced lipid peroxidation although their effectiveness decreased with dephosphorylation. Similarly, they also prevented iron ion-induced decomposition of phosphatidylcholine hydroperoxide. These results demonstrate that intermediate products of phytic acid hydrolysis still possess iron ion-chelating ability, and thus they can probably prevent iron ion-induced lipid peroxidation in biological systems.

  20. Properties of colloidal corrosion products and their effects on nuclear plants: Final report

    SciTech Connect

    Matijevic, E.

    1986-12-01

    A number of different solid particles found in nuclear reactor coolant have been produced in the laboratory. Such particles result from corrosion processes at metal piping and component surfaces. The particles produced and studied in this work differ from those observed in power plant water in two respects: (1) they are all of one narrowly controlled particle diameter and particle shape; (2) they are all of one simple composition - such as magnetite or hematite. The methods for making new supplies of these particles are provided for use by those wishing to study, for example, how best to dissolve surface oxides during a decontamination of plant piping surfaces. The model oxides aid in sorting out the proper dissolution procedures by providing a well-defined simulation of each separate constituent of plant surfaces in a form where dissolution rates are easily measured. Measurements of the properties of magnetite, hematite, and nickel-iron-cobalt ferrites relevant to radioactive cobalt-60 transport have been made and are reported in summary form. Some of these properties studied are (1) cobalt adsorption as a function of temperature and pH; (2) magnetic properties to assess the ease of magnetic filtration; (3) dissolution rates by the commonly employed decontamination chemicals. Copies of 41 separate scientific journal publications resulting from this work are reproduced in microfiche in the back cover pocket.

  1. Iron (III) porphyrin aggregates grafted on agarose gel as models of hemoglobin degradation products

    NASA Astrophysics Data System (ADS)

    Brémard, C.; Girerd, J. J.; Merlin, J. C.; Moreau, S.

    1992-03-01

    The degradation of hemoglobin by the intraerythrocytic Malaria parasite Plasmodium generates a pseudo crystalline dark product : the Malaria pigment. In a modeling effort to mimic the aggregation of the degradation products we have undertaken the synthesis of iron (III) protoporphyrin aggregates using grafted iron protoporphyrin on agarose gel. We demonstrate using Resonance Raman microspectrometry, EPR spectroscopy and magnetic measurements that the Malaria pigment is an aggregate of monomeric iron (III) protoporphyrin hydroxide compound.

  2. Ecotoxicity of Concretes with Granulated Slag from Gray Iron Pilot Production as Filler.

    PubMed

    Hybská, Helena; Hroncová, Emília; Ladomerský, Juraj; Balco, Karol; Mitterpach, Jozef

    2017-05-06

    This paper focuses on research concerning the ecotoxicological properties of granulated slag from the pilot production of gray iron with red mud addition and concrete composites with the application of this slag. Red mud is a hazardous waste generated in the production of aluminium oxide. Negative ecotoxicological tests are, therefore, one of the basic prerequisites for the ability to use granulated slag from gray iron pilot production. Granulated slag and concrete composite samples with various ratios of granulated slag have been subject to ecotoxicity tests: determining root growth inhibition in the highly-cultivated plant Sinapisalba, and determining acute toxicity in Daphniamagna. The results of ecotoxicological testing of granulated slag from gray iron standard production and gray iron pilot production with the additive were, according to the standard (STN 83 8303), negative. Additionally, the results of ecotoxicological tests of concrete composites were negative, with the exception of a 50% substitution of fine aggregate with slag from gray iron pilot production.

  3. Iron Fertilization and Productivity in the Panama Basin

    NASA Astrophysics Data System (ADS)

    Loveley, M. R.; Marcantonio, F.; Lyle, M. W.; Hertzberg, J. E.

    2016-12-01

    The Panama Basin, located in the Eastern Equatorial Pacific, is a high-nutrient low-chlorophyll zone (HNLC). HNLC zones are thought to be iron limited, and thus have low rates of primary productivity. Iron can be delivered to the ocean by continental dust, and times of increased dust flux are thought to be correlated with increased productivity. However, few studies have addressed the relationship between dust flux and primary productivity in the Panama Basin. We use xs230Th-derived 232Th accumulation rates as a dust flux proxy, and excess Ba, and authigenic U to reconstruct primary productivity in the basin. We focus on these proxies' differences between glacial and interglacial times for the last five marine isotope stages, during which glacial times are dustier. Our study involves two marine sediment cores, one retrieved from the northern part of the Panama Basin at the Cocos Ridge, (MV1014-01-"8JC", 6° 14.0'N 86° 2.6' W, 1993 m depth), and one from the southern part of the basin at the Carnegie Ridge, (MV1014-02-"17JC" 0° 10.8'S 85° 52.0' W, 2846 m depth). Both cores record high sedimentation rates (between 4 and 20 cm kyr-1) which allow us to present a high-resolution study of the basin. However, sediment focusing and the preferential transport of fine grained material have been identified in these cores. In the Panama Basin, the lithogenic dust fraction is part of the fine fraction (<4 µm) influenced by sediment focusing. Our recent research has shown that 230Th-normalized MARs of the fine-grained fraction remain relatively unaffected by the redistribution process. Our preliminary findings show that dust flux may not have played a major role in influencing primary productivity during glacial periods in the Panama Basin. Other factors, such as nutrient consumption or nutrient supply from upwelled deep water, may have had a more dominant role during these times.

  4. 75 FR 25841 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-10

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...'') published a notice of initiation of the administrative review of the antidumping duty order on...

  5. 76 FR 17381 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-29

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of Final Results of the Sixteenth Administrative Review Correction In notice document...

  6. 76 FR 21332 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-15

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...'') published a notice of initiation of the administrative review of the antidumping duty order on...

  7. 77 FR 25405 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...'') published a notice of initiation of the administrative review of the antidumping duty order on...

  8. Fate of corrosion products released from stainless steel in marine sediments and seawater. Part 1. Northeast Pacific pelagic red clay

    SciTech Connect

    Schmidt, R.L.

    1982-03-01

    To provide information useful for determining the biogeochemical cycling of corrosion products in the benthic boundary layer of the deep ocean, neutron-activated stainless steel was exposed to seawater and to Northeast Pacific red clay under aerobic and non-oxygenated conditions. This report describes the trace metal geochemistry of the sediment and the chemical speciation of the corrosion products. The sediments generally consisted of reddish-brown clay at the surface grading to a dark-brown transition zone below which mottled olive-gray clay prevailed. Neutron-irradiated 347 stainless steel specimens were exposed to seawater and sediment slurry under aerobic and non-oxygenated conditions for 108 days. The presence of aerated sediment more than doubled the amount of corrosion products released compared to aerated seawater and non-oxygenated sediment treatments. The distribution of /sup 60/Co released from the stainless steel exposed to aerated seawater show that almost 70% of /sup 60/Co activity became associated with suspended particulate matter. No detectable /sup 60/Co activity was present in the soluble, readily dissolved, or inorganic or weakly complexed fractions of aerated sediment which had been used to treat neutron-activated stainless steel. Almost 50% of the /sup 60/Co activity was extracted in the combined soluble, easily dissolved, adsorbed, and organically complexed fractions from the non-oxygenated sediment treatment indicating that this much of the corrosion products may be initially released in ionic form.

  9. 75 FR 55745 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Preliminary Results...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-14

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... Administration, International Trade Administration, Department of Commerce. SUMMARY: The Department of Commerce..., Office 3, Import Administration, International Trade Administration, ] U.S. Department of Commerce, Room...

  10. Synchrotron based x-ray fluorescence microscopy confirms copper in the corrosion products of metals in contact with treated wood

    Treesearch

    Samuel L. Zelinka; Joseph E. Jakes; Grant T. Kirker; David Vine; Stefan Vogt

    2017-01-01

    Copper based waterborne wood preservatives are frequently used to extend the service life of wood products when subjected to frequent moisture exposure. While these copper based treatments protect the wood from fungal decay and insect attack, they increase the corrosion of metals embedded or in contact with the treated wood. Previous research has shown the most...

  11. A process for the production of a scale-proof and corrosion-resistant coating on graphite and carbon bodies

    NASA Technical Reports Server (NTRS)

    Fitzer, E.

    1981-01-01

    A process for the production of a corrosion resistant coating on graphite and carbon bodies is described. The carbon or graphite body is coated or impregnated with titanium silicide under the addition of a metal containing wetting agent in a nitrogen free atmosphere, so that a tight coating is formed.

  12. Experimental investigation of solid by-product as sensible heat storage material: Characterization and corrosion study

    NASA Astrophysics Data System (ADS)

    Ortega-Fernández, Iñigo; Faik, Abdessamad; Mani, Karthik; Rodriguez-Aseguinolaza, Javier; D'Aguanno, Bruno

    2016-05-01

    The experimental investigation of water cooled electrical arc furnace (EAF) slag used as filler material in the storage tank for sensible heat storage application was demonstrated in this study. The physicochemical and thermal properties of the tested slags were characterized by using X-ray diffraction, scanning electron microcopy, Fourier transform infrared spectroscopy, Raman spectroscopy and laser flash analysis, respectively. In addition, the chemical compatibility between slags and molten nitrate salt (60 wt. % NaNO3 and 40 wt. % KNO3) was investigated at 565 °C for 500 hrs. The obtained results were clearly demonstrated that the slags showed a good corrosion resistance in direct contact with molten salt at elevated temperature. The present study was clearly indicated that a low-cost filler material used in the storage tank can significantly reduce the overall required quantities of the relatively higher cost molten salt and consequently reduce the overall cost of the electricity production.

  13. Associations between iron concentration and productivity in montane streams of the Black Hills, South Dakota

    USGS Publications Warehouse

    Hayer, Cari Ann; Holcomb, Benjamin M.; Chipps, Steven R.

    2013-01-01

    Iron is an important micronutrient found in aquatic systems that can influence nutrient availability (e.g., phosphorus) and primary productivity. In streams, high iron concentrations often are associated with low pH as a result of acid mine drainage, which is known to affect fish and invertebrate communities. Streams in the Black Hills of South Dakota are generally circumneutral in pH, yet select streams exhibit high iron concentrations associated with natural iron deposits. In this study, we examined relationships among iron concentration, priphyton biomass, macroinvertebrate abundance, and fish assemblages in four Black Hills streams. The stream with the highest iron concentration (~5 mg Fe/L) had reduced periphyton biomass, invertebrate abundance, and fish biomass compared to the three streams with lower iron levels (0.1 to 0.6 mg Fe/L). Reduced stream productivity was attributed to indirect effects of ferric iron Fe+++), owing to iron-hydroxide precipitation that influenced habitat quality (i.e., substrate and turbidity) and food availability (periphyton and invertebrates) for higher trophic levels (e.g., fish). Additionally, reduced primary and secondary production was associated with reduced standing stocks of salmonid fishes. Our findings suggested that naturally occurring iron deposits may constrain macroinvertebrate and fish production.

  14. General corrosion, irradiation-corrosion, and environmental-mechanical evaluation of nuclear waste package structural barrier materials. Progress report

    SciTech Connect

    Westerman, R.E.; Pitman, S.G.; Nelson, J.L.

    1982-09-01

    Pacific Northwest Laboratory is studying the general corrosion, irradiation-corrosion, and environmentally enhanced crack propagation of five candidate materials in high-temperature aqueous environments simulating those expected in basalt and tuff repositories. The materials include three cast ferrous materials (ductile cast iron and two low-alloy Cr-Mo cast steels) and two titanium alloys, titanium Grade 2 (commercial purity) and Grade 12 (a Ti-Ni-Mo alloy). The general corrosion results are being obtained by autoclave exposure of specimens to slowly replenished simulated ground water flowing upward through a bed of the appropriate crushed rock (basalt or tuff), which is maintained at the desired test temperature (usually 250/sup 0/C). In addition, tests are being performed in deionized water. Metal penetration rates of iron-base alloys are being derived by stripping off the corrosion product film and weighing the specimen after the appropriate exposure time. The corrosion of titanium alloy specimens is being determined by weight gain methods. The irradiation-corrosion studies are similar to the general corrosion tests, except that the specimen-bearing autoclaves are held in a /sup 60/Co gamma radiation field at dose rates up to 2 x 10/sup 6/ rad/h. For evaluating the resistance of the candidate materials to environmentally enhanced crack propagation, three methods are being used: U-bend and fracture toughness specimens exposed in autoclaves; slow strain rate studies in repository-relevant environments to 300/sup 0/C; and fatigue crack growth rate studies at ambient pressure and 90/sup 0/C. The preliminary data suggest a 1-in. corrosion allowance for iron-base barrier elements intended for 1000-yr service in basalt or tuff repositories. No evidence has yet been found that titanium Grade 2 or Grade 12 is susceptible to environmentally induced crack propagation or, by extension, to stress corrosion cracking.

  15. Comments on "Sorption of triazoles to soil and iron minerals" by Y. Jia et al. [Chemosphere 67 (2007) 250-258].

    PubMed

    Noubactep, C

    2008-03-01

    This letter suggests possible improvements on the discussion of the adsorptive removal of triazoles by iron minerals which are possible corrosion products of elemental iron materials (Fe0) in a recent article by Jia et al. [Jia, Y., Aagaard, P., Breedveld, G.D., 2007. Sorption of triaxoles to soil and iron materials. Chemosphere 67, 250-258]. Also recalled is the importance of the adsorption of organics by iron corrosion products which is not properly addressed in the iron technology literature when the contaminants are redox-sensitive.

  16. Mineralogical Fingerprints for Corrosion Processes Induced

    DTIC Science & Technology

    1990-01-01

    distribution is unlimited. ’ Abstract (Maximum 200 words). MineralogicaL data, thermodynamic stability ( Pourbaix ) diagrams , and the simpLexity principle for...stability ( Pourbaix ) diagrams , and the simplexity principle for precipitation reactions are used to rationalize corrosion product mineralogy in a...excluding those found in coal mine and peat-bog situations. In Figure 2, parallelograms have been superimposed on a Pourbaix diagram for iron in water

  17. Localized corrosion of 316L stainless steel in tritiated water containing aggressive radiolytic and decomposition products at different temperatures

    NASA Astrophysics Data System (ADS)

    Bellanger, G.

    2008-02-01

    Tritium is one of the more important radionuclides used in nuclear industry as plutonium and uranium. The tritium in tritiated water always causes difficulties in nuclear installations, including equipment corrosion. Moreover, with tritiated water there are, in addition, the radiolytic and decomposition products such as hydrogen peroxide formed during decay, chloride ions produced by degradation of organic seals and oils used for tightness and pumping, and acid pH produced by excitation of nitrogen in air by the β - particle. Highly concentrated tritiated water releases energy and its temperature is about 80 °C, moreover heating is necessary in the tritium processes. These conditions highly facilitate the corrosion of stainless steels by pitting and crevice attack. Corrosion tests were performed by electrochemical analysis methods and by visual inspection of the surface of stainless steel.

  18. Zirconium alloys with small amounts of iron and copper or nickel show improved corrosion resistance in superheated steam

    NASA Technical Reports Server (NTRS)

    Greenberg, S.; Youngdahl, C. A.

    1967-01-01

    Heat treating various compositions of zirconium alloys improve their corrosion resistance to superheated steam at temperatures higher than 500 degrees C. This increases their potential as fuel cladding for superheated-steam nuclear-fueled reactors as well as in autoclaves operating at modest pressures.

  19. Microbial Methane Production Associated with Carbon Steel Corrosion in a Nigerian Oil Field.

    PubMed

    Mand, Jaspreet; Park, Hyung S; Okoro, Chuma; Lomans, Bart P; Smith, Seun; Chiejina, Leo; Voordouw, Gerrit

    2015-01-01

    Microbially influenced corrosion (MIC) in oil field pipeline systems can be attributed to many different types of hydrogenotrophic microorganisms including sulfate reducers, methanogens and acetogens. Samples from a low temperature oil reservoir in Nigeria were analyzed using DNA pyrotag sequencing. The microbial community compositions of these samples revealed an abundance of anaerobic methanogenic archaea. Activity of methanogens was demonstrated by incubating samples anaerobically in a basal salts medium, in the presence of carbon steel and carbon dioxide. Methane formation was measured in all enrichments and correlated with metal weight loss. Methanogens were prominently represented in pipeline solids samples, scraped from the inside of a pipeline, comprising over 85% of all pyrosequencing reads. Methane production was only witnessed when carbon steel beads were added to these pipeline solids samples, indicating that no methane was formed as a result of degradation of the oil organics present in these samples. These results were compared to those obtained for samples taken from a low temperature oil field in Canada, which had been incubated with oil, either in the presence or in the absence of carbon steel. Again, methanogens present in these samples catalyzed methane production only when carbon steel was present. Moreover, acetate production was also found in these enrichments only in the presence of carbon steel. From these studies it appears that carbon steel, not oil organics, was the predominant electron donor for acetate production and methane formation in these low temperature oil fields, indicating that the methanogens and acetogens found may contribute significantly to MIC.

  20. Microbial Methane Production Associated with Carbon Steel Corrosion in a Nigerian Oil Field

    PubMed Central

    Mand, Jaspreet; Park, Hyung S.; Okoro, Chuma; Lomans, Bart P.; Smith, Seun; Chiejina, Leo; Voordouw, Gerrit

    2016-01-01

    Microbially influenced corrosion (MIC) in oil field pipeline systems can be attributed to many different types of hydrogenotrophic microorganisms including sulfate reducers, methanogens and acetogens. Samples from a low temperature oil reservoir in Nigeria were analyzed using DNA pyrotag sequencing. The microbial community compositions of these samples revealed an abundance of anaerobic methanogenic archaea. Activity of methanogens was demonstrated by incubating samples anaerobically in a basal salts medium, in the presence of carbon steel and carbon dioxide. Methane formation was measured in all enrichments and correlated with metal weight loss. Methanogens were prominently represented in pipeline solids samples, scraped from the inside of a pipeline, comprising over 85% of all pyrosequencing reads. Methane production was only witnessed when carbon steel beads were added to these pipeline solids samples, indicating that no methane was formed as a result of degradation of the oil organics present in these samples. These results were compared to those obtained for samples taken from a low temperature oil field in Canada, which had been incubated with oil, either in the presence or in the absence of carbon steel. Again, methanogens present in these samples catalyzed methane production only when carbon steel was present. Moreover, acetate production was also found in these enrichments only in the presence of carbon steel. From these studies it appears that carbon steel, not oil organics, was the predominant electron donor for acetate production and methane formation in these low temperature oil fields, indicating that the methanogens and acetogens found may contribute significantly to MIC. PMID:26793176

  1. Reline 33 year old kettle for more corrosive process at about 1/3 cost of new unit: lightweight foamed glass block protects corroded cast iron cover

    SciTech Connect

    Not Available

    1982-06-01

    This article presents a solution to a chemical plant's need for a lining material to reline a 33 year old kettle that would be resistant to attack by aqueous bromine and hydrochloric, nitrous, and bromic acid. The solution was to use an elastomeric polyisobutylene sheeting as a primary lining for the kettle. The problem was also solved by using a light weight foamed glass block which protected the corroded cast iron dome cover for the kettle. Installation of the two-step lining for the kettle and cover by Chemsteel Construction Company of New Kensington, PA was completed in 5 weeks. The cost was about 1/3 as much as fabricating, installing, and lining a new steel 5000 gal vessel. The kettle has been in service about 12 months and the acid brick/polyisobutylene membrance liner shows no signs of damage from the highly corrosive chemicals and elevated temperatures required for the process change.

  2. Corrosion performance of structural alloys.

    SciTech Connect

    Natesan, K.

    1999-07-15

    Component reliability and long-term trouble-free performance of structural materials are essential in power-generating and gasification processes that utilize coal as a feedstock. During combustion and conversion of coal, the environments encompass a wide range of oxygen partial pressures, from excess-air conditions in conventional boilers to air-deficient conditions in 10W-NO{sub x} and gasification systems. Apart from the environmental aspects of the effluent from coal combustion and conversion, one concern from the systems standpoint is the aggressiveness of the gaseous/deposit environment toward structural components such as waterwall tubes, steam superheaters, syngas coolers, and hot-gas filters. The corrosion tests in the program described in this paper address the individual and combined effects of oxygen, sulfur, and chlorine on the corrosion response of several ASME-coded and noncoded structural alloys that were exposed to air-deficient and excess-air environments typical of coal-combustion and gasification processes. Data in this paper address the effects of preoxidation on the subsequent corrosion performance of structural materials such as 9Cr-1Mo ferritic steel, Type 347 austenitic stainless steel, Alloys 800, 825, 625, 214, Hastelloy X, and iron aluminide when exposed at 650 C to various mixed-gas environments with and without HCI. Results are presented for scaling kinetics, microstructural characteristics of corrosion products, detailed evaluations of near-surface regions of the exposed specimens, gains in our mechanistic understanding of the roles of S and Cl in the corrosion process, and the effect of preoxidation on subsequent corrosion.

  3. Corrosion fatigue of iron-chromium-nickel alloys: Fracture mechanics, microstructure and chemistry. Progress report, December 1, 1990--December 31, 1992

    SciTech Connect

    Wei, R.P.

    1992-01-29

    This progress report briefly summarizes the research performed under the referenced grant for the period from 1 December 1990 to 31 December 1991, and contains a cumulative listing of technical presentations and publications dating back to 1 June 1988. Under this grant, a multi-disciplinary research program is undertaken to address certain fundamental issues relating to corrosion fatigue crack growth in structurally important alloys in aqueous environments. The principal goal of the research is to develop and expand the scientific understanding of the processes that control corrosion fatigue crack growth, particularly for ferrous alloys in terms of the controlling mechanical and chemical/electrochemical processes and their interactions with the microstructure. Focus is placed upon the austenitic iron-chromium-nickel (FeCrNi) alloys because of the need to resolve certain mechanistic issues and because of extensive utilization of these alloys in the power generation and chemical industries. Emphasis is given to the growth of short (small) cracks at low growth rates because crack growth in this regime is expected to be more sensitive to changes in external chemical/electrochemical variables.

  4. Methane production by large iron meteorite impacts on early Earth

    NASA Astrophysics Data System (ADS)

    Sekine, Yasuhito; Sugita, Seiji; Kadono, Toshihiko; Matsui, Takafumi

    2003-07-01

    The continuous existence of life on the Earth is thought to have begun around 4 Ga, which is near the end of the heavy bombardment period. Impacts of asteroids and comets may have produced and delivered organic matter on the Hadean Earth. However, the nature of those processes has not been understood well yet. In this paper, we propose a new process of organic synthesis induced by asteroid impacts. We consider the effect of impact vapor condensates reentering the Earth's early atmosphere. Vapor condensates produced by a large-scale impact are dispersed around the globe and reenter the atmosphere at very high speed. The reentering condensates are heated and decelerated by the friction with the atmosphere and form a ``hot condensate layer'' around the globe. We calculate the temperature and atmospheric pressure of the hot condensate layer as a function of time. A Fischer-Tropsch reaction on the surface of the reentering iron and nickel condensates will lead to efficient methane production. The reaction rate of Fischer-Tropsch catalysis is estimated based on a kinetic model. Calculation results indicate that the amount of methane produced by the impact of an iron meteorite with a diameter of 10 km at 15 km sec-1 of velocity reaches ~1012-1013 kg. Some of the methane formed by this process is photodissociated to HCN and organic aerosols. The amount of the resulting HCN is estimated to be ~1010-1012 kg. This is 103-104 times the preimpact inventory of HCN on the Earth, which is maintained by UV radiation and electric discharge in a mildly reducing (i.e., CO-CO2 dominant) atmosphere. Such an episodic increase in the organic inventory on the surface of the early Earth may have played an important role in the origin of life.

  5. Influence of hydronium, sulfate, chloride and other non-carbonate ions on hydrogen generation by anaerobic corrosion of granular cast iron.

    PubMed

    Ruhl, Aki S; Jekel, Martin

    2013-10-15

    Permeable reactive barriers are successfully applied for the removal of various contaminants. The concomitant reduction of hydrogen ions and the subsequent formation of hydrogen gas by anaerobic corrosion lead to decreased pore volume filled with water and thus residence times, so called gas clogging. Long term column experiments were conducted to elucidate the impact of ubiquitous water constituents on the formation of hydrogen gas and potential passivation due to corrosion products. The collected gas volumes revealed a relation to the hydronium concentration (pH) but were only slightly increased in the presence of chloride and sulfate and not significantly influenced in the presence of phosphate, silicate, humic acid and ammonium compared to deionized water. Significant gas volumes within the reactive filling were verified by gravimetry. The presence of nitrate completely eliminated hydrogen formation by competition for electrons. Solid phase analyses revealed that neither chloride nor sulfate was incorporated in corrosion products in concentrations above 0.1 weight percent, and they did not alter the formation of mainly magnetite in comparison to deionized water.

  6. Microbes adapt to iron scarcity through siderophore production across the eastern tropical Pacific

    NASA Astrophysics Data System (ADS)

    Repeta, D.; Boiteau, R.; Mende, D. R.; DeLong, E.

    2016-02-01

    Iron regulates microbial growth and carbon fixation rates in vast regions of the ocean characterized by high nutrient and low chlorophyll (HNLC) concentrations. As competition for bioavailable iron in HNLC regions intensifies, microbial communities face tremendous selective pressure to develop efficient uptake and utilization strategies that access the strong organic ligands controlling iron bioavailability in these areas. Using liquid chromatography mass spectrometry, we found 27 unique iron complexes in surface waters sampled across the GEOTRACES eastern tropical Pacific zonal cruise track, with a clear trend in the abundance of different ligands across nutrient regimes. We identified siderophores, compounds produced by microbes under iron stress to facilitate iron uptake, as important components of iron ligands. Siderophore composition varied dramatically across the region, reflecting adaptive microbial strategies for acquiring iron. Concentrations of amphibactins, amphiphilic siderophores with cell membrane affinity, were low in coastal waters, but reached 9pM in HNLC waters, while ferrioxamine concentrations were higher in coastal and oligotrophic regions (1-2pM). These spatial changes in siderophore distributions represents adaptations used by marine microbes to acquire iron under different ecological conditions. To infer the potential ocean-wide contribution of amphibactins to microbial iron acquisition, we investigated the distribution of amphibactin synthesis genes in the recently published TARA Oceans metagenomic catalogue. We found amphibactin synthesis genes were present in other major iron-starved regions, suggesting that adaptations involving siderophore utilization likely impact global marine ecosystem composition and productivity.

  7. Control of community growth and export production by upwelled iron in the equatorial Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Coale, Kenneth H.; Fitzwater, Steve E.; Gordon, R. Michael; Johnson, Kenneth S.; Barber, Richard T.

    1996-02-01

    THE 'iron hypothesis'1,2 states that phytoplankton growth and biomass are limited by low concentrations of available iron in large regions of the world's oceans where other plant nutrients are abundant. Such limitation has been demonstrated by experiments in which iron has been added to both enclosed and in situ (un-enclosed) phytoplankton populations2-6. A corollary of the iron hypothesis is that most 'new' iron is supplied by atmospheric deposition7,8, and it has been suggested that changes in the deposition rates of iron-bearing dust have led to changes in biological productivity and, consequently, global climate7. Here we report surface-water measurements in the equatorial Pacific Ocean which show that the main iron source to equatorial waters at 140° W is from upwelling waters. Shipboard in vitro experiments indicate that sub-nanomolar increases in iron concentrations can cause substantial increases in carbon export to deeper waters in this region. These findings demonstrate that equatorial biological production is controlled not solely by atmospheric iron deposition, but also by processes which influence the rate of upwelling and the iron concentration in upwelled water.

  8. Effect of Temperature on the Corrosion Behavior of API X120 Pipeline Steel in H2S Environment

    NASA Astrophysics Data System (ADS)

    Okonkwo, Paul C.; Sliem, Mostafa H.; Shakoor, R. A.; Mohamed, A. M. A.; Abdullah, Aboubakr M.

    2017-08-01

    The corrosion behavior of newly developed API X120 C-steel that is commenced to be used for oil pipelines was studied in a H2S saturated 3.5 wt.% NaCl solution between 20 and 60 °C using potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The corrosion products formed on the surface of the alloy were characterized using x-ray diffraction and scanning electron microscopy. It has been noticed that the formation of corrosion product layer takes place at both lower and higher temperatures which is mainly comprised of iron oxides and sulfides. The electrochemical results confirmed that the corrosion rate decreases with increasing temperature up to 60 °C. This decrease in corrosion rate with increasing temperature can be attributed to the formation of a protective layer of mackinawite layer. However, cracking in the formed mackinawite layer may not be responsible for the increase in the corrosion rate. More specifically, developed pourbaix diagrams at different temperatures showed that the formed protective layer belongs to mackinawite (FeS), a group of classified polymorphous iron sulfide, which is in good agreement with the experimental results. It is also noticed that the thickness of corrosion products layer increases significantly with decrease in the corrosion rate of API X120 steel exposed to H2S environment. These findings indicate that API X120 C-steel is susceptible to sour corrosion under the above stated experimental conditions.

  9. Marine and offshore corrosion

    SciTech Connect

    Chandler, K.A.

    1985-01-01

    Until recently marine corrosion technology has been preoccupied with the corrosion of ships. Within the last ten years, however, the rapid expansion of oil and gas exploration has changed the course of corrosion research as well as the market for corrosion services and products. So complete has been the change that a new approach, dealing with ships, structures, and plant has been taken in this book. This introduction to the control of corrosion in marine environments will serve as a reference on topics ranging from coating systems to metallurgical considerations in the design of ships, offshore structure, plant and pipelines.

  10. WASTE PACKAGE CORROSION STUDIES USING SMALL MOCKUP EXPERIMENTS

    SciTech Connect

    B.E. Anderson; K.B. Helean; C.R. Bryan; P.V. Brady; R.C. Ewing

    2005-10-19

    The corrosion of spent nuclear fuel and subsequent mobilization of radionuclides is of great concern in a geologic repository, particularly if conditions are oxidizing. Corroding A516 steel may offset these transport processes within the proposed waste packages at the Yucca Mountain Repository (YMR) by retaining radionuclides, creating locally reducing conditions, and reducing porosity. Ferrous iron, Fe{sup 2+}, has been shown to reduce UO{sub 2}{sup 2+} to UO{sub 2(s)} [1], and some ferrous iron-bearing ion-exchange materials adsorb radionuclides and heavy metals [2]. Of particular interest is magnetite, a potential corrosion product that has been shown to remove TcO{sub 4}{sup -} from solution [3]. Furthermore, if Fe{sup 2+} minerals, rather than fully oxidized minerals such as goethite, are produced during corrosion, then locally reducing conditions may be present. High electron availability leads to the reduction and subsequent immobilization of problematic dissolved species such as TcO{sub 4}{sup -}, NpO{sub 2}{sup +}, and UO{sub 2}{sup 2+} and can also inhibit corrosion of spent nuclear fuel. Finally, because the molar volume of iron material increases during corrosion due to oxygen and water incorporation, pore space may be significantly reduced over long time periods. The more water is occluded, the bulkier the corrosion products, and the less porosity is available for water and radionuclide transport. The focus of this paper is on the nature of Yucca Mountain waste package steel corrosion products and their effects on local redox state, radionuclide transport, and porosity.

  11. A model of the ocean iron cycle and its influence on biological production

    NASA Astrophysics Data System (ADS)

    Dutkiewicz, S.; Parekh, P.; Follows, M.

    2003-04-01

    Biological productivity in large regions of the ocean, specifically high nutrient, low chlorophyll regions, is limited by the deficit in iron relative to other nutrients. We have developed a parameterization of the iron cycle of the world's oceans which attempts to explicitly represent the processes by which this deficit in iron occurs. We have implemented this parameterization in the context of the MIT three dimensional global ocean model and examined the consequences for nutrient distributions, new production and primary production. The iron model parameterizes the mechanisms of scavenging of iron onto sinking particles and complexation with an organic ligand and is driven by specified aeolian flux patterns. First, using an idealized representation of export production, limited by light, phosphate and iron, the model reproduces the broad features of the observed ocean phosphate and iron distributions. We replace the simplified export parameterization with an explicit, but highly idealized, ecosystem model. The model represents a simplified food web with two phytoplankton size classes and a single grazer. The base currency for this model is phosphorus, but the larger phytoplankton class (i.e. diatoms) is also limited by silica. Both classes are limited by the availability of iron. The results of this model are also generally consistent with the observed patterns of phosphate and iron. In addition, the model captures the broad features of the distributions and cycles of silica, chlorophyll and primary production. We will also explore the sensitivities of this model to the forcing fields (e.g. aeolian iron flux) and parameter choices of the ecosystem model. This model represents a step towards the explicit representation of the ocean iron cycle, and its biogeochemical influences, in global biogeochemical models.

  12. Investigation of the weldability of iron-aluminum-chromium overlay coatings for corrosion protection in oxidizing/sulfidizing environments

    NASA Astrophysics Data System (ADS)

    Regina, Jonathan R.

    The current study investigated the effect of chromium additions on the hydrogen cracking susceptibility of Fe-Al weld overlay claddings containing chromium additions. It was found that the weldability of FeAlCr claddings was a function of both the aluminum and chromium concentrations of the weld coatings. Weld overlay compositions that were not susceptible to hydrogen cracking were identified and the underlying mechanism behind the hydrogen cracking phenomenon was investigated further. It was concluded that the cracking behavior of the FeAlCr welds depended strongly on the microstructure of the weld fusion zone. Although it was found that the cracking susceptibility was influenced by the presence of Fe-Al intermetallic phases (namely Fe3 Al and FeAl), the cracking behavior of FeAlCr weld overlay claddings also depended on the size and distribution of carbide and oxide particles present within the weld structure. These particles acted as hydrogen trapping sites, which are areas where free hydrogen segregates and can no longer contribute to the hydrogen embrittlement of the metal. It was determined that in practical applications of these FeAlCr weld overlay coatings, carbon should be present within these welds to reduce the amount of hydrogen available for hydrogen cracking. Based on the weldability results of the FeAlCr weld claddings, coating compositions that were able to be deposited crack-free were used for long-term corrosion testing in a simulated low NOx environment. These alloys were compared to a Ni-based superalloy (622), which is commonly utilized as boiler tube coatings in power plant furnaces for corrosion protection. It was found that the FeAlCr alloys demonstrated superior corrosion resistance when compared to the Ni-based superalloy. Due to the excellent long-term corrosion behavior of FeAlCr weld overlays that were immune to hydrogen cracking, it was concluded that select FeAlCr weld overlay compositions would make excellent corrosion resistant

  13. Al-26 and Be-10 production in iron meteorites

    NASA Technical Reports Server (NTRS)

    Aylmer, D.; Bonanno, V.; Herzog, G. F.; Weber, H.; Klein, J.

    1988-01-01

    To compare the Al-26/Ne-21 ages with K-40/K-41 ages, the contents of Al-26 were determined in seven iron meteorites using accelerator mass spectrometry and the light noble gas contents were determined using conventional mass spectrometry, for samples for which these values were not available. In addition, contents of Be-10 were measured. Due to the presence of boron in the samples, the values of Al-26 were found to be at least 30 percent lower than the literature values obtained by low-level counting techniques, while the Be-10 values were 10-15 percent lower. The production rates of these nuclides at different He-4/Ne-21 ratios were estimated, showing that the increase in He-4/Ne-21 ratios corresponded with decreases in Al-26 and Be-10. It was shown that the exposure ages calculated from the Ne-21/Al-26 ratio cannot be calibrated so as to agree with both the K-40/K-41 ages and ages based on the shorter-lived nuclides Ar-39 and Cl-36.

  14. Surface modification for corrosion protection of steel pipes

    NASA Astrophysics Data System (ADS)

    Morshed, Ali

    Corrosion of carbon steel oil pipelines in the sweet environments has been a well- known problem in the oil industry all over the world and corrosion inhibitors of the film forming type have been widely used to combat this type of corrosion. In this project numerous effort has been made to devise a similar way of corrosion mitigation by producing an impermeable and protective coating made of precipitated iron carbonate scale. Based on the previous works it was suggested that iron carbonate scale as the corrosion product (of carbon steel and CO2) could to some extent offer protection to its substrate and reduce the corrosion rate effectively. However, precipitating an adherent and protective iron carbonate scale has not been an easy job. Our main objectives during this work have been firstly to define the favourable conditions under which an iron carbonate scale would precipitate in the system and then to investigate how the protective characteristics of the scale could be improved. The effects of several environmental variables like solution pH, solution temperature, additives (scale inhibitors), stirring and solution composition on the scale properties such as adhesion, surface coverage, stability and porosity (scale density) have been investigated. Simultaneously, the adverse effects of certain conditions or variables that tended to reduce the scale protectiveness or prevent its precipitation have been investigated and discussed. Some of the presented results are rather qualitative; nevertheless it is believed that they have contributed in the better understanding of the iron carbonate scale properties and its precipitation process. Based on the results and conclusions of this project few suggestions have been made at the end for the possible continuation of this work.

  15. PHOTOCHEICAL PRODUCTION OF HYDROXYL RADICAL IN NATURAL WATER - THE ROLE OF IRON AND DISSOLVED ORGANIC MATTER

    EPA Science Inventory

    Photochemical hydroxyl radical (OH) production was measured in several natural waters to investigate the importance of colored dissolved organic matter (CDOM) and iron-CDOM complexes as sources of OH. High rates of OH photoproduction in highly colored, iron-rich, acidic waters a...

  16. PHOTOCHEICAL PRODUCTION OF HYDROXYL RADICAL IN NATURAL WATER - THE ROLE OF IRON AND DISSOLVED ORGANIC MATTER

    EPA Science Inventory

    Photochemical hydroxyl radical (OH) production was measured in several natural waters to investigate the importance of colored dissolved organic matter (CDOM) and iron-CDOM complexes as sources of OH. High rates of OH photoproduction in highly colored, iron-rich, acidic waters a...

  17. Corrosion product deposits on boiling-water reactor cladding: Experimental and theoretical investigation of magnetic properties

    NASA Astrophysics Data System (ADS)

    Orlov, A.; Degueldre, C.; Wiese, H.; Ledergerber, G.; Valizadeh, S.

    2011-09-01

    Recent Eddy current investigations on the cladding of nuclear fuel pins have shown that the apparent oxide layers are falsified due to unexpected magnetic properties of corrosion product deposits. Analyses by Scanning Electron Microscopy (SEM) or Electron Probe Micro Analysis (EPMA) demonstrated that the deposit layer consists of complex 3-d element oxides (Ni, Mn, Fe) along with Zn, since the reactor operates with a Zn addition procedure to reduce buildup of radiation fields on the recirculation system surfaces. The oxides crystallise in ferritic spinel structures. These spinels are well-known for their magnetic behaviour. Since non-magnetic zinc ferrite (ZnFe 2O 4) may become magnetic when doped with even small amounts of Ni and/or Mn, their occurrence in the deposit layer has been analyzed. The magnetic permeability of zinc ferrite, trevorite and jacobsite and their solid solutions are estimated by magnetic moment additivity. From the void history examination, the low elevation sample (810 mm) did not face significant boiling during the irradiation cycles suggesting growth of (Mn0.092+Zn0.752+Fe0.293+)[(Fe1.713+Mn0.032+Ni0.132+)O] crystals with theoretical value of the magnetic permeability for the averaged heterogeneous CRUD layer of 9.5 ± 3. Meanwhile, (Mn0.162+Zn0.552+Fe0.293+)[(Fe1.713+Mn0.042+Ni0.252+)O] crystallizes at the mid elevation (1810 mm) with theoretical magnetic permeability for the CRUD layer of 4.2 ± 1.5 at the investigated azimuthal location. These theoretical data are compared with the magnetic permeability of the corrosion product deposited layers gained from reactor pool side Eddy current (EC) analyses (9.0 ± 1.0 for low and 3.5 ± 1.0 for high elevation). The calculated thicknesses and magnetic permeability values of the deposition layers (estimated by MAGNACROX multifrequency EC method) match together with these estimated using an "ion magnetic moment additivity" model.

  18. Kinetic study for phenol degradation by ZVI-assisted Fenton reaction and related iron corrosion investigated by X-ray absorption spectroscopy.

    PubMed

    Yoon, In-Ho; Yoo, Gursong; Hong, Hye-Jin; Kim, Jungmin; Kim, Min Gyu; Choi, Wang-Kyu; Yang, Ji-Won

    2016-02-01

    In this study, we investigated phenol degradation via zero-valent iron (ZVI)-assisted Fenton reaction through kinetic and spectroscopic analysis. In batch experiments, 100 mg/L of phenol was completely degraded, and 75% of TOC was removed within 3 min under an optimal hydrogen peroxide (H2O2) concentration (50 mM) via the Fenton reaction. In the absence of H2O2, oxygen (O2) was dissolved into the solution and produced H2O2, which resulted in phenol degradation. However, phenol removal efficiency was not very high compared to external H2O2 input. The Fenton reaction rapidly occurred at the surface of ZVI, and then phenol mobility from the solution to the ZVI surface was the rate determining step of the whole reaction. The pseudo-second order adsorption kinetic model well describes phenol removal, and its rate increased according to the H2O2 concentration. X-ray absorption spectroscopic analysis revealed that iron oxide (Fe-O bonding) was formed on ZVI with [H2O2] > 50 mM. A high concentration of H2O2 led to rapid degradation of phenol and caused corrosion on the ZVI surface, indicating that Fe(2+) ions were rapidly oxidized to Fe(3+) ions due to the Fenton reaction and that Fe(3+) was precipitated as iron oxide on the ZVI surface. However, ZVI did not show corroded characteristics in the absence of H2O2 due to the insufficient ZVI-assisted Fenton reaction and oxidation of Fe(2+) to Fe(3+).

  19. The problems of mass transfer and formation of deposits of corrosion products on fuel assemblies of a VVER-1200 reactor

    NASA Astrophysics Data System (ADS)

    Rodionov, Yu. A.; Kritskii, V. G.; Berezina, I. G.; Gavrilov, A. V.

    2014-03-01

    On the basis of examination of materials published both in Russia and abroad, as well as their own investigations, the authors explain the reasons for the occurrence of such effects as AOA (Axial Offset Anomalies) and an increase in the coolant pressure difference in the core of nuclear reactors of the VVER type. To detect the occurrence of the AOA effect, the authors suggest using the specific activity of 58Co in the coolant. In the VVER-1200 design the thermohydraulic regime for fuel assemblies in the first year of their service life involves slight boiling of the coolant in the upper part of the core, which may induce the occurrence of the AOA effect, intensification of corrosion of fuel claddings, and abnormal increase in deposition of corrosion products. Radiolysis of the water coolant in the boiling section (boiling in pores of deposits) may intensify not only general corrosion but also a localized (nodular) one. As a result of intensification of the corrosion processes and growth of deposits, deterioration of the radiation situation in the rooms of the primary circuit of a VVER-1200 reactor as compared to that at nuclear power plants equipped with reactors of the VVER-1000 type is possible. Recommendations for preventing the AOA effect at nuclear power plants with VVER-1200 reactors on the matter of the direction of further investigations are made.

  20. Non-animal testing strategies for assessment of the skin corrosion and skin irritation potential of ingredients and finished products.

    PubMed

    Robinson, M K; Cohen, C; de Fraissinette, A de Brugerolle; Ponec, M; Whittle, E; Fentem, J H

    2002-05-01

    The dermatotoxicologist today is faced with a dilemma. Protection of workers and consumers from skin toxicities (irritation and allergy) associated with exposure to products, and the ingredients they contain, requires toxicological skin testing prior to manufacture, transport, or marketing. Testing for skin corrosion or irritation has traditionally been conducted in animals, particularly in rabbits via the long established Draize test method. However, this procedure, among others, has been subject to criticism, both for its limited predictive capacity for human toxicity, as well as for its use of animals. In fact, legislation is pending in the European Union which would ban the sale of cosmetic products, the ingredients of which have been tested in animals. These considerations, and advancements in both in vitro skin biology and clinical testing, have helped drive an intensive effort among skin scientists to develop alternative test methods based either on in vitro test systems (e.g. using rat, pig or human skin ex vivo, or reconstructed human skin models) or ethical clinical approaches (human volunteer studies). Tools are now in place today to enable a thorough skin corrosion and irritation assessment of new ingredients and products without the need to test in animals. Herein, we describe general testing strategies and new test methods for the assessment of skin corrosion and irritation. The methods described, and utilized within industry today, provide a framework for the practicing toxicologist to support new product development initiatives through the use of reliable skin safety testing and risk assessment tools and strategies.

  1. Laboratory study related to the production and properties of pig iron nuggets

    SciTech Connect

    Anameric, B.; Kawatra, S.K.

    2006-02-15

    Pig iron nuggets were produced in a laboratory-scale furnace at Michigan Technological University. The process was intended to replicate Kobe Steel's ITmk3 direct ironmaking process. These nuggets were produced from pellets that were made from a mixture of iron oxide, coal, flux and a binder and heated in a furnace with a chamber temperature of 1450{sup o}C. The pellets then self-reduced to produce a solid, high-density, highly metallized (96.5% Fe) pig iron. During the nugget production process, a separate liquid slag phase formed that cleanly separated from the molten metal. The physical and chemical properties of the pig iron nuggets were similar to pig iron produced by blast furnaces, which is distinct from direct reduced iron (DRI).

  2. Iron sucrose accelerates early atherogenesis by increasing superoxide production and upregulating adhesion molecules in CKD.

    PubMed

    Kuo, Ko-Lin; Hung, Szu-Chun; Lee, Tzong-Shyuan; Tarng, Der-Cherng

    2014-11-01

    High-dose intravenous iron supplementation is associated with adverse cardiovascular outcomes in patients with CKD, but the underlying mechanism is unknown. Our study investigated the causative role of iron sucrose in leukocyte-endothelium interactions, an index of early atherogenesis, and subsequent atherosclerosis in the mouse remnant kidney model. We found that expression levels of intracellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) and adhesion of U937 cells increased in iron-treated human aortic endothelial cells through upregulated NADPH oxidase (NOx) and NF-κB signaling. We then measured mononuclear-endothelial adhesion and atherosclerotic lesions of the proximal aorta in male C57BL/6 mice with subtotal nephrectomy, male apolipoprotein E-deficient (ApoE(-/-)) mice with uninephrectomy, and sham-operated mice subjected to saline or parenteral iron loading. Iron sucrose significantly increased tissue superoxide production, expression of tissue cell adhesion molecules, and endothelial adhesiveness in mice with subtotal nephrectomy. Moreover, iron sucrose exacerbated atherosclerosis in the aorta of ApoE(-/-) mice with uninephrectomy. In patients with CKD, intravenous iron sucrose increased circulating mononuclear superoxide production, expression of soluble adhesion molecules, and mononuclear-endothelial adhesion compared with healthy subjects or untreated patients. In summary, iron sucrose aggravated endothelial dysfunction through NOx/NF-κB/CAM signaling, increased mononuclear-endothelial adhesion, and exacerbated atherosclerosis in mice with remnant kidneys. These results suggest a novel causative role for therapeutic iron in cardiovascular complications in patients with CKD.

  3. A vegetarian diet rich in soybean products compromises iron status in young students.

    PubMed

    Shaw, N S; Chin, C J; Pan, W H

    1995-02-01

    The iron status of young Chinese Buddhist vegetarians (23 men and 32 women) and nonvegetarian students (20 men and 39 women from a medical college) was investigated by dietary assessment of iron intake and hematological measurement of biochemical indices including hemoglobin, plasma iron, transferrin, transferrin saturation and plasma ferritin. A characteristic of the vegetarian diet in this study was the replacement of meat by soybean products. Results of the dietary assessment showed that the average iron density of the diets ranged from 1.9 to 2.2 mg/MJ, with no difference between the vegetarian and nonvegetarian diets. Daily iron intake was similar in both vegetarian and nonvegetarian men. However, iron intake was significantly higher in female vegetarians than nonvegetarians, averaging 104 and 78% of the RDA, respectively. Results of blood analysis showed that, for both sexes, the median plasma ferritin concentration of the vegetarians (male 47 micrograms/L and female 12 micrograms/L) was about half the level of the nonvegetarians (male 91 micrograms/L and female 27 micrograms/L). Occurrence and risk of iron deficiency are more prevalent in vegetarians. Correlation between plasma ferritin concentration and years of vegetarian practice in vegetarian men was marginally significant (r = -0.38, P = 0.077). We conclude that a vegetarian diet that is rich in soybean products and restricted in animal foods is limited in bioavailable iron and is not adequate for maintaining iron balance in men and women.

  4. Intergranular stress corrosion cracking and selective internal oxidation of nickel-chromium-iron alloys in hydrogenated steam

    NASA Astrophysics Data System (ADS)

    Capell, Brent M.

    2005-07-01

    Selective internal oxidation (SIO) is a mechanism of grain boundary embrittlement through the formation of intergranular oxides of Cr2O3. SIO is proposed as a mechanism to explain intergranular stress corrosion cracking (IGSCC) of Ni-base alloys in pressurized water reactor environments. The purpose of this work is to investigate SIO through a series of experiments using controlled-purity alloys in a controlled, low-pressure steam environment in which the oxygen potential is varied. Five alloys; Ni-9Fe, Ni-5Cr, LCr (Ni-5Cr-9Fe), CD85 (Ni-16Cr-9Fe) and HCr (Ni-30Cr-9Fe), were used in corrosion coupon exposure tests and constant extension rate tensile (CERT) tests at 550°C and 400°C in an environment consisting of a controlled mixture of hydrogen, water vapor and argon. The hydrogen-to-water vapor partial pressure ratio (PPR) was varied between 0.001 and 0.9 to control the oxygen partial pressure. The Ni-9Fe, Ni-5Cr and LCr alloys formed a uniform Ni(OH)2 film at PPR values less than 0.09 while CD85 and HCr formed Cr2O 3 oxide films over the entire PPR range. Corrosion coupon results also show the formation of highly localized oxide particles at grain boundaries. Focused ion beam analysis revealed that intergranular oxides were observed at significant depths (>150 nm) down grain boundaries and the oxide morphology depended on the alloy composition and PPR value. Diffusion of oxygen along the grain boundary accounted for the growth of intergranular oxides. CERT test results showed that intergranular cracking was caused by creep-induced microvoid coalescence only at 550°C and did not depend on PPR. At 400°C, the cracking behavior depended on the PPR and resulted in a mixture of creep-induced microvoid coalescence and brittle intergranular failure. The cracked boundary fraction was higher at a PPR value where a Ni(OH)2 surface film formed. Alloy composition influenced cracking and the cracked boundary fraction decreased as the alloy chromium content increased. The

  5. Corrosion behavior of ruthenium oxide-titanium anodes during production of sodium chlorate by electrolysis of chloride-chlorate solutions

    SciTech Connect

    Uzbekov, A.A.; Klement 'pva, V.S.; Kubasov, V.L.; Lambrev, V.G.

    1985-09-01

    The authors studied the influence of specific factors in chlorate electrilysis on the corrosion behavior of ROTA. The technique used in the investigation was based on neutron activation of the test specimens followed by corrosion tests. Figures show the dependence rate of ruthenium dissolution on the sodium chloride production during production of chlorate by electrolysis with ROTA, and dependence of the rate of ruthenium dissolution and of the rate of oxygen evolution during polarization of ROTA. Over the entire range of ROTA potentials studied the process of oxygen evolution conforms to the Tafel relationship. The rate of ruthenium dissolution in chlorate solution rises by more than 4 orders of magnitude with increase of the ROTA potential.

  6. Uncommon corrosion phenomena of archaeological bronze alloys

    NASA Astrophysics Data System (ADS)

    Ingo, G. M.; de Caro, T.; Riccucci, C.; Khosroff, S.

    2006-06-01

    In the framework of the EFESTUS project (funded by the European Commission, contract No. ICA3-CT-2002-10030) the corrosion products of a large number of archaeological bronze artefacts are investigated by means of the combined use of scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD) and optical microscopy (OM) and tentative correlation of their nature with the chemical composition of the artefacts and the burial context is proposed. The results provide good insight into the corrosion layers and evidence in some bronze Roman coins and artefacts; the occurrence of uncommon corrosion phenomena that give rise to the formation of a yellowish-green complex chlorine-phosphate of lead (pyromorphite, (PbCl)Pb4(PO4)3) and of a gold-like thick layer of an iron and copper sulphide (chalcopyrite, CuFeS2). The micro-chemical and micro-structural results show that the coins were buried in a soil enriched in phosphorus for the accidental presence of a large amount of decomposing fragments of bones or in an anaerobic and humus rich soil where the chalcopyrite layer has been produced via the interaction between the iron of the soil, the copper of the coin and the sulphur produced by the decomposition of organic matter in an almost oxygen free environment. Finally, some unusual periodic corrosion phenomena occurring in high tin bronze mirrors found at Zama (Tunisia) are described.

  7. Micro-Raman study of copper hydroxychlorides and other corrosion products of bronze samples mimicking archaeological coins.

    PubMed

    Bertolotti, Giulia; Bersani, Danilo; Lottici, Pier Paolo; Alesiani, Marcella; Malcherek, Thomas; Schlüter, Jochen

    2012-02-01

    Three bronze samples created by CNR-ISMN (National Research Council-Institute of Nanostructured Materials) to be similar to Punic and Roman coins found in Tharros (OR, Sardinia, Italy) were studied to identify the corrosion products on their surfaces and to evaluate the reliability of the reproduction process. Micro-Raman spectroscopy was chosen to investigate the corroded surfaces because it is a non-destructive technique, it has high spatial resolution, and it gives the opportunity to discriminate between polymorphs and to correlate colour and chemical composition. A significant amount of green copper hydroxychlorides (Cu(2)(OH)(3)Cl) was detected on all the coins. Their discrimination by Raman spectroscopy was challenging because the literature on the topic is currently confusing. Thus, it was necessary to determine the characteristic peaks of atacamite, clinoatacamite, and the recently discovered anatacamite by acquiring Raman spectra of comparable natural mineral samples. Clinoatacamite, with different degrees of order in its structure, was the major component identified on the three coins. The most widespread corrosion product, besides hydroxychlorides, was the red copper oxide cuprite (Cu(2)O). Other corrosion products of the elements of the alloy (laurionite, plumbonacrite, zinc carbonate) and those resulting from burial in the soil (anatase, calcite, hematite) were also found. This study shows that identification of corrosion products, including discrimination of copper hydroxychlorides, could be accomplished by micro-Raman on valuable objects, for example archaeological findings or works of art, avoiding any damage because of extraction of samples or the use of a destructive analytical technique.

  8. Combined use of SEM-EDS, OM and XRD for the characterization of corrosion products grown on silver roman coins

    NASA Astrophysics Data System (ADS)

    Ingo, G. M.; Balbi, S.; de Caro, T.; Fragalà, I.; Angelini, E.; Bultrini, G.

    2006-06-01

    In the framework of the PROMET project (European Commission contract No. 509126) aimed to develop new analytical techniques and materials for monitoring and protecting metal artefacts and monuments from the Mediterranean region, the corrosion products grown on silver Roman coins during archaeological burial is studied by means of scanning electron microscopy combined with energy dispersive spectrometry (SEM-EDS), X-ray diffraction (XRD) and optical microscopy (OM) techniques.

  9. Effect of water chemistry on the dissolution rate of the lead corrosion product hydrocerussite.

    PubMed

    Noel, James D; Wang, Yin; Giammar, Daniel E

    2014-05-01

    Hydrocerussite (Pb3(CO3)2(OH)2) is widely observed as a corrosion product in drinking water distribution systems. Its equilibrium solubility and dissolution rate can control lead concentrations in drinking water. The dissolution rate of hydrocerussite was investigated as a function of pH, dissolved inorganic carbon (DIC), and orthophosphate concentrations at conditions relevant to drinking water distribution using continuously stirred tank reactors (CSTRs). In the absence of DIC and orthophosphate, the dissolution rate decreased with increasing pH. Addition of DIC inhibited the dissolution of hydrocerussite. The addition of orthophosphate significantly decreased the dissolution rate of hydrocerussite. At conditions with orthophosphate and without DIC, a lead(II) phosphate solid hydroxylpyromorphite (Pb5(PO4)3OH) was observed after reaction, and orthophosphate's inhibitory effect can be attributed to the formation of this low-solubility lead(II) phosphate solid. In the presence of both orthophosphate and DIC, no lead(II) phosphate solid was observed, but the rate was still lowered by the presence of orthophosphate, which might be due to the adsorption of orthophosphate to block reactive sites on the hydrocerussite surface. For systems in which hydroxylpyromorphite was present, the steady-state effluent lead concentrations from the CSTRs were close to the predicted equilibrium solubility of hydroxylpyromorphite. In the absence of orthophosphate rapid equilibration of hydrocerussite was observed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Impact of chlorine disinfectants on dissolution of the lead corrosion product PbO2.

    PubMed

    Xie, Yanjiao; Wang, Yin; Giammar, Daniel E

    2010-09-15

    Plattnerite (β-PbO(2)) is a corrosion product that develops on lead pipes that have been in contact with free chlorine present as a residual disinfectant. The reductive dissolution of PbO(2) can cause elevated lead concentrations in tap water when the residual disinfectant is switched from free chlorine to monochloramine. The objectives of this study were to quantify plattnerite dissolution rates in the presence of chlorine disinfectants, gain insights into dissolution mechanisms, and measure plattnerite's equilibrium solubility in the presence of free chlorine. The effects of free chlorine and monochloramine on the dissolution rates of plattnerite were quantified in completely mixed continuous-flow reactors at relevant pH and dissolved inorganic carbon conditions. Plattnerite dissolution rates decreased in the following order: no disinfectant > monochloramine > chlorine, which was consistent with the trend in the redox potential. Compared with experiments without disinfectant, monochloramine inhibited plattnerite dissolution in continuous-flow experiments. Although free chlorine maintained steady-state lead concentrations below the action level of 15 μg/L in flow-through experiments, in batch experiments lead concentrations exceeded the action level for longer residence times and approached an equilibrium value that was several orders of magnitude higher than that predicted from available thermodynamic data.

  11. Mineralogy and crystal chemistry of iron in the Timan bauxite and products of their technological processing

    NASA Astrophysics Data System (ADS)

    Kotova, O.; Silaev, V.; Lutoev, V.; Vakhrushev, A.

    2016-04-01

    Mineralogical and geochemical features of two series of samples of typical bauxites from two deposits of Middle Timan mining area (Vezhayu-Vorykva and Svetlinskoe) were studied. The phase composition of ferrous bauxites generally is boehmite, hematite, ultradisperse low-ordered goethite and berthierine. In a boehmite and kaolinite structural impurity of iron to 10%, and in the iron oxidehydroxides aluminum impurity is revealed. On iron content bauxites are subdivided into three mineral types for which quantitative data on valence states of ions of iron and proportions of their distribution last on nonequivalent structural positions in hematite, goethite and berthierine are obtained. Noble metals (Ag, Au, Ir, Rh, Pd) concentrating in bauxites are revealed for the first time. Obtained data can lead to decrease of power consumption during aluminum production and high quality ceramics, to provide production of valuable iron oxide, and also to minimize the ecological harm from accumulation of bauxite wastes.

  12. Iron control in west Texas sour-gas wells provides sustained production increases

    SciTech Connect

    Walker, M.L.; Dill, W.R.; Besler, M.R.; McFatridge, D.G. )

    1991-05-01

    Permian Basin operators have recorded sustained production increases in oil wells by preventing precipitation of iron sulfide and other sulfur-containing species. This improvement has resulted largely from cleaning out tubing before acidizing and from preventing the precipitation of ferrous sulfide and the formation of elemental sulfur by simultaneous use of iron chelants and sulfide-control agents. Previously used methods gave only temporary production increases that terminated when iron dissolved by the stimulation acid reprecipitated in the pay zone and damage the formation after the stimulation acid was spent. This paper describes a method to optimize iron sulfide control, methods to minimize reprecipitation, and case histories from the Permian Basin that show improved methods to control iron in sour-well environments.

  13. Effect of Annealing on the Passive Film Stability and Corrosion Resistance of New Families of Iron-Based Amorphous Metals

    DTIC Science & Technology

    2011-06-01

    in the expected carbides or borides . Although these phases are potentially present, they do not exist in any large quantity. SAM4X7 has similar...score for titanium mixed with iron and chromium. Once again, titanium carbide and titanium boride did not appear in any large quantity. Because

  14. KINETICS OF SOLUBLE CHROMIUM REMOVAL FROM CONTAMINATED WATER BY ZEROVALENT IRON MEDIA: CORROSION INHIBITION AND PASSIVE OXIDE EFFECTS. (R825223)

    EPA Science Inventory

    Permeable reactive barriers containing zerovalent iron are being increasingly
    employed for in situ remediation of groundwater contaminated with redox active
    metals and chlorinated organic compounds. This research investigated the effect
    of chromate concentration on...

  15. KINETICS OF SOLUBLE CHROMIUM REMOVAL FROM CONTAMINATED WATER BY ZEROVALENT IRON MEDIA: CORROSION INHIBITION AND PASSIVE OXIDE EFFECTS. (R825223)

    EPA Science Inventory

    Permeable reactive barriers containing zerovalent iron are being increasingly
    employed for in situ remediation of groundwater contaminated with redox active
    metals and chlorinated organic compounds. This research investigated the effect
    of chromate concentration on...

  16. The Impact of Bacterial Strain on the Products of Dissimilatory Iron Reduction

    PubMed Central

    Salas, Everett C.; Berelson, William M.; Hammond, Douglas E.; Kampf, Anthony R.; Nealson, Kenneth H.

    2009-01-01

    Three bacterial strains from the genus Shewanella were used to examine the influence of specific bacteria on the products of dissimilatory iron reduction. Strains CN32, MR-4 and W3-18-1 were incubated with HFO (hydrous ferric oxide) as the terminal electron acceptor and lactate as the organic carbon and energy source. Mineral products of iron reduction were analyzed using X-ray powder diffraction, electron microscopy, coulometry and susceptometry. Under identical nutrient loadings, iron reduction rates for strains CN32 and W3-18-1 were similar, and about twice as fast as MR-4. Qualitative and quantitative assessment of mineralized end products (secondary minerals) indicated that different products were formed during experiments with similar reduction rates but different strains (CN32 and W3-18-1), and similar products were formed during experiments with different iron reduction rates and different strains (CN32 and MR-4). The major product of iron reduction by strains CN32 and MR-4 was magnetite, while for W3-18-1 it was a mixture of magnetite and iron carbonate hydroxide hydrate (green rust), a precursor to fougerite. Another notable difference was that strains CN32 and MR-4 converted all of the starting ferric iron material into magnetite, while W3-18-1 did not convert most of the Fe3+ into a recognizable crystalline material. Biofilm formation is more robust in W3-18-1 than in the other two strains used in this study. The differences in mineralization may be an indicator that EPS (or another cellular product from W3-18-1) may interfere with the crystallization of magnetite or facilitate formation of green rust. These results suggest that the relative abundance of mineral end products and the relative distribution of these products are strongly dependent on the bacterial species or strain catalyzing iron reduction. PMID:20161499

  17. Investigation of the inhibiting action of O-, S- and N-dithiocarbamato(1,4,8,11-tetraazacyclotetradecane)cobalt(III) complexes on the corrosion of iron in HClO 4 acid

    NASA Astrophysics Data System (ADS)

    Babić-Samardžija, K.; Khaled, K. F.; Hackerman, N.

    2005-02-01

    The inhibiting properties of four macrocyclic cobalt(III) complexes of the general formula [Co III(Rdtc)cyclam](ClO 4) 2, where cyclam and Rdtc- refer to 1,4,8,11-tetraazacyclotetradecane and morpholine-, thiomorpholine-, piperazine-, N-methylpiperazine-dithiocarbamates, respectively, has been studied on the corrosion of iron in aerated 0.1 M HClO 4 solutions by potentiodynamic polarization (dc) technique and electrochemical impedance spectroscopy (ac). Inhibitor efficiency for the corrosion of iron is found to be better for cobalt complexes then for related amino-ligands. The impedance increases with inhibitor concentration. Polarization curves indicate that the inhibitors are predominantly mixed-type. Better protection by the complex inhibitors was obtained with longer immersion time. The best fit for inhibitors adsorption is obtained using the Langmuir isotherm model. Molecular modeling calculations were used to correlate structural properties of the complex species and their inhibition efficiency.

  18. Characterization of Copper Corrosion Products in Drinking Water by Combining Electrochemical and Surface Analyses

    EPA Science Inventory

    This study focuses on the application of electrochemical approaches to drinking water copper corrosion problems. Applying electrochemical approaches combined with copper solubility measurements, and solid surface analysis approaches were discussed. Tafel extrapolation and Electro...

  19. Characterization of Copper Corrosion Products Formed in Drinking Water by Combining Electrochemical and Surface Analyses

    EPA Science Inventory

    This study focuses on the application of electrochemical approaches to drinking water copper corrosion problems. Applying electrochemical approaches combined with copper solubility measurements, and solid surface analysis approaches were discussed. Tafel extrapolation and Electro...

  20. Characterization of Copper Corrosion Products Formed in Drinking Water by Combining Electrochemical and Surface Analyses

    EPA Science Inventory

    This study focuses on the application of electrochemical approaches to drinking water copper corrosion problems. Applying electrochemical approaches combined with copper solubility measurements, and solid surface analysis approaches were discussed. Tafel extrapolation and Electro...

  1. Characterization of Copper Corrosion Products in Drinking Water by Combining Electrochemical and Surface Analyses

    EPA Science Inventory

    This study focuses on the application of electrochemical approaches to drinking water copper corrosion problems. Applying electrochemical approaches combined with copper solubility measurements, and solid surface analysis approaches were discussed. Tafel extrapolation and Electro...

  2. Enhanced High Temperature Corrosion Resistance in Advanced Fossil Energy Systems by Nano-Passive Layer Formation

    SciTech Connect

    Arnold R. Marder

    2007-06-14

    Due to their excellent corrosion resistance, iron aluminum alloys are currently being considered for use as weld claddings in fossil fuel fired power plants. The susceptibility to hydrogen cracking of these alloys at higher aluminum concentrations has highlighted the need for research into the effect of chromium additions on the corrosion resistance of lower aluminum alloys. In the present work, three iron aluminum alloys were exposed to simulated coal combustion environments at 500 C and 700 C for both short (100 hours) and long (5,000 hours) isothermal durations. Scanning electron microscopy was used to analyze the corrosion products. All alloys exhibited excellent corrosion resistance in the short term tests. For longer exposures, increasing the aluminum concentration was beneficial to the corrosion resistance. The addition of chromium to the binary iron aluminum alloy prevented the formation iron sulfide and resulted in lower corrosion kinetics. A classification of the corrosion products that developed on these alloys is presented. Scanning transmission electron microscopy (STEM) of the as-corroded coupons revealed that chromium was able to form chromium sulfides only on the higher aluminum alloy, thereby preventing the formation of deleterious iron sulfides. When the aluminum concentration was too low to permit selective oxidation of only aluminum (upon initial exposure to the corrosion environment), the formation of chromium oxide alongside the aluminum oxide led to depletion of chromium beneath the oxide layer. Upon penetration of sulfur through the oxide into this depletion layer, iron sulfides (rather than chromium sulfides) were found to form on the low aluminum alloy. Thus, it was found in this work that the role of chromium on alloy corrosion resistance was strongly effected by the aluminum concentration of the alloy. STEM analysis also revealed the encapsulation of external iron sulfide products with a thin layer of aluminum oxide, which may provide a

  3. High temperature corrosion studies. A. Iron: based superalloy in SO/sub 2//O/sub 2/ atmospheres. B. Gas: solid reaction with formation of volatile species

    SciTech Connect

    Liu, T.K.

    1980-03-01

    The thermogravimetric method was used to study high temperature corrosion under SO/sub 2//O/sub 2/ atmosphere applied to Armco 18SR alloys with different heat treatment histories, Armco T310 and pure chromium between 750 and 1100/sup 0/C. The weight gain follows the parabolic rate law. The volatilization of the protective Cr/sub 2/O/sub 3/ layer via formation of CrO/sub 3/ was taken into account above 900/sup 0/C for long time runs. The parabolic rate and the volatilization rate, derived from fitting the experimental data to the modified Tedmon's non-linear model, were correlated using the Arrhenius equation. Armco 18SR-C has the best corrosion resistance of the Armco 18SR alloys. Armco T310 is not protective at high temperatures. The available rate data on the oxidation of chromium oxide, chlorination of chromium, oxidation-chlorination of chromium oxide, chlorination of nickel and chlorination of iron were found to be predictable. The calculation of high temperature volatilization rate was performed using the available fluid correlation equations and the Lennard-Jones parameters derived from the molecule with similar structure and from the low temperature viscosity measurement. The lower predicted volatilization rate is due to the use of the Chapman-Enskog equation with the Lennard-Jones parameters mostly derived from the low temperature viscosity measurement. This was substantiated by comparing the reliable high temperature diffusion rate in the literature with the above mentioned calculational method. The experimental volatilization rates of this study are compared with the other related studies and the mass transfer predictions.

  4. 49 CFR 192.487 - Remedial measures: Distribution lines other than cast iron or ductile iron lines.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... STANDARDS Requirements for Corrosion Control § 192.487 Remedial measures: Distribution lines other than cast iron or ductile iron lines. (a) General corrosion. Except for cast iron or ductile iron pipe, each... engineering tests and analyses show can permanently restore the serviceability of the pipe. Corrosion...

  5. 49 CFR 192.487 - Remedial measures: Distribution lines other than cast iron or ductile iron lines.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... STANDARDS Requirements for Corrosion Control § 192.487 Remedial measures: Distribution lines other than cast iron or ductile iron lines. (a) General corrosion. Except for cast iron or ductile iron pipe, each... engineering tests and analyses show can permanently restore the serviceability of the pipe. Corrosion...

  6. 49 CFR 192.487 - Remedial measures: Distribution lines other than cast iron or ductile iron lines.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... STANDARDS Requirements for Corrosion Control § 192.487 Remedial measures: Distribution lines other than cast iron or ductile iron lines. (a) General corrosion. Except for cast iron or ductile iron pipe, each... engineering tests and analyses show can permanently restore the serviceability of the pipe. Corrosion pitting...

  7. 49 CFR 192.487 - Remedial measures: Distribution lines other than cast iron or ductile iron lines.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... STANDARDS Requirements for Corrosion Control § 192.487 Remedial measures: Distribution lines other than cast iron or ductile iron lines. (a) General corrosion. Except for cast iron or ductile iron pipe, each... engineering tests and analyses show can permanently restore the serviceability of the pipe. Corrosion pitting...

  8. 49 CFR 192.487 - Remedial measures: Distribution lines other than cast iron or ductile iron lines.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... STANDARDS Requirements for Corrosion Control § 192.487 Remedial measures: Distribution lines other than cast iron or ductile iron lines. (a) General corrosion. Except for cast iron or ductile iron pipe, each... engineering tests and analyses show can permanently restore the serviceability of the pipe. Corrosion pitting...

  9. Cytotoxicity of corrosion products of degradable Fe-based stents: relevance of pH and insoluble products.

    PubMed

    Fagali, Natalia S; Grillo, Claudia A; Puntarulo, Susana; Fernández Lorenzo de Mele, Mónica A

    2015-04-01

    Fe-based biodegradable metallic materials (Fe-BMMs) have been proposed for cardiovascular applications and are expected to disappear via corrosion after an appropriate period. However, in vivo studies showed that Fe ions release leads to accumulation of orange and brownish insoluble products at the biomaterial/cell interface. As an additional consequence, sharp changes in pH may affect the biocompatibility of these materials. In the present work, the experimental protocols were designed with the aim of evaluating the relative importance that these factors have on biocompatibility evaluation of BMMs. Mitochondrial activity (MTT assay) and thiobarbituric acid reactive substances (TBARS) assay on mammalian cells, exposed to 1-5 mM of added Fe3+ salt, were assessed and compared with results linked exclusively to pH effects. Soluble Fe concentration in culture medium and intracellular Fe content were also determined. The results showed that: (i) mitochondrial activity was affected by pH changes over the entire range of concentrations of added Fe3+ assayed, (ii) at the highest added Fe3+ concentrations (≥3 mM), precipitation was detected and the cells were able to incorporate the precipitate, that seems to be linked to cell damage, (iii) the extent of precipitation depends on the Fe/protein concentration ratio; and (iv) lipid peroxidation products were detected over the entire range of concentrations of added Fe3+. Hence, a new approach opens in the biocompatibility evaluation of Fe-based BMMs, since the cytotoxicity would not be solely a function of released (and soluble) ions but of the insoluble degradation product amount and the pH falling at the biomaterial/cell interface. The concentration of Fe-containing products at the interface depends on diffusional conditions in a very complex way that should be carefully analyzed in the future.

  10. Microbially Promoted Solubilization of Steel Corrosion Products and Fate of Associated Actinides

    SciTech Connect

    Gorby, Yuri A.; Geesey, Gill G.; Caccavo Jr., Frank; Fredrickson, James K.

    2002-06-01

    The U.S. Department of Energy (DOE) statements of need call for ''biological and physical chemical parameters for effective decontamination of metal surfaces using environmentally benign aqueous-based biopolymer solutions and microbial processes with potential for decontaminating corroding metal surfaces.'' Improved understanding of the fundamental processes of microbial reductive dissolution of iron oxide scale on corroding carbon steel will support assessment and potential application of an environmentally benign and cost-effective strategy for in situ decontamination of structural metal surfaces and piping. This research is designed to develop a safe and effective biological approach for decontaminating mild and stainless steels that were used in the production, transport, and storage of radioactive materials.

  11. The influence of the corrosion product layer generated on the high strength low-alloy steels welded by underwater wet welding with stainless steel electrodes in seawater

    NASA Astrophysics Data System (ADS)

    Bai, Qiang; Zou, Yan; Kong, Xiangfeng; Gao, Yang; Dong, Sheng; Zhang, Wei

    2017-02-01

    The high strength low-alloy steels are welded by underwater wet welding with stainless steel electrodes. The micro-structural and electrochemical corrosion study of base metal (BM), weld zone (WZ) and heat affected zone (HAZ) are carried out to understand the influence of the corrosion product layer generated on the high strength low-alloy steels welded by underwater wet welding with stainless steel electrodes, methods used including, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). The results indicate that the WZ acts as a cathode and there is no corrosion product on it throughout the immersion period in seawater. The HAZ and BM acts as anodes. The corrosion rates of the HAZ and BM change with the immersion time increasing. In the initial immersion period, the HAZ has the highest corrosion rate because it has a coarse tempered martensite structure and the BM exhibites a microstructure with very fine grains of ferrite and pearlite. After a period of immersion, the BM has the highest corrosion rate. The reason is that the corrosion product layer on the HAZ is dense and has a better protective property while that on the BM is loose and can not inhibit the diffusion of oxygen.

  12. Tubercles and Localized Corrosion on Carbon Steel

    DTIC Science & Technology

    2011-02-16

    with symbiotic relationships and nutrient cycling. Miller and Tiller [14] indicated, "iron bacteria , which, together with the ferric hydroxide they...be used to conclude localized corrosion directly under the tubercles or a role for bacteria in their formation. 15. SUBJECT TERMS tubercle...corrosion, iron-oxidizing bacteria , magnetite 16. SECURITY CLASSIFICATION OF: a. REPORT Unclassified b. ABSTRACT Unclassified c. THIS PAGE

  13. Nonenzymatic glycation of transferrin: decrease of iron-binding capacity and increase of oxygen radical production.

    PubMed

    Fujimoto, S; Kawakami, N; Ohara, A

    1995-03-01

    The total iron-binding capacity (TIBC) and iron contents of diabetic rat serum, as well as the iron-binding capacity of glycated transferrin and oxygen radical production by the glycated proteins were examined. The TIBC and iron content of diabetic rat sera were found to be much lower than those of control rat sera. Incubation of human serum with glucose in vitro resulted in a significant fall of its unsaturated iron-binding capacity (UIBC) with time. When apotransferrin was incubated with glucose, its UIBC significantly decreased. The iron content of holotransferrin was markedly reduced by incubation with bathophenanthroline sulphonic acid (BPSA) in the presence of glucose, although the content was not altered by incubation with BPSA alone. The generation of superoxide radical (O2-) and hydroxyl radical (OH.) by the glycated holotransferrin was much greater than that by glycated apotransferrin. Glycated holotransferrin showed significantly accelerated hydroxyl radical production by the hypoxanthine-xanthine oxidase system, while intact holotransferrin did not. Treatment of holotransferrin with glucose caused the fragmentation of the protein, while the same treatment of apotransferrin did not. These results suggest that iron ions in the glycated transferrin molecule are bound loosely to the protein and are redox-active and the glycated holotransferrin produces oxygen radicals including O2- and OH. efficiently, and that the glycated transferrin does not function as an iron-binding protein.

  14. Formation Sequences of Iron Minerals in the Acidic Alteration Products and Variation of Hydrothermal Fluid Conditions

    NASA Astrophysics Data System (ADS)

    Isobe, H.; Yoshizawa, M.

    2008-12-01

    Iron minerals have important role in environmental issues not only on the Earth but also other terrestrial planets. Iron mineral species related to alteration products of primary minerals with surface or subsurface fluids are characterized by temperature, acidity and redox conditions of the fluids. We can see various iron- bearing alteration products in alteration products around fumaroles in geothermal/volcanic areas. In this study, zonal structures of iron minerals in alteration products of the geothermal area are observed to elucidate temporal and spatial variation of hydrothermal fluids. Alteration of the pyroxene-amphibole andesite of Garan-dake volcano, Oita, Japan occurs by the acidic hydrothermal fluid to form cristobalite leaching out elements other than Si. Hand specimens with unaltered or weakly altered core and cristobalite crust show various sequences of layers. XRD analysis revealed that the alteration degree is represented by abundance of cristobalite. Intermediately altered layers are characterized by occurrence including alunite, pyrite, kaolinite, goethite and hematite. A specimen with reddish brown core surrounded by cristobalite-rich white crust has brown colored layers at the boundary of core and the crust. Reddish core is characterized by occurrence of crystalline hematite by XRD. Another hand specimen has light gray core, which represents reduced conditions, and white cristobalite crust with light brown and reddish brown layers of ferric iron minerals between the core and the crust. On the other hand, hornblende crystals, typical ferrous iron-bearing mineral of the host rock, are well preserved in some samples with strongly decolorized cristobalite-rich groundmass. Hydrothermal alteration experiments of iron-rich basaltic material shows iron mineral species depend on acidity and temperature of the fluid. Oxidation states of the iron-bearing mineral species are strongly influenced by the acidity and redox conditions. Variations of alteration

  15. Influence of hydrogen-oxidizing bacteria on the corrosion of low carbon steel: Local electrochemical investigations.

    PubMed

    Moreira, Rebeca; Schütz, Marta K; Libert, Marie; Tribollet, Bernard; Vivier, Vincent

    2014-06-01

    Low carbon steel has been considered a suitable material for component of the multi-barrier system employed on the geological disposal of high-level radioactive waste (HLW). A non negligible amount of dihydrogen (H2) is expected to be produced over the years within the geological repository due to the anoxic corrosion of metallic materials and also to the water radiolysis. The influence of the activity of hydrogen-oxidizing bacteria (HOB) and iron-reducing bacteria (IRB) on carbon steel corrosion is considered in this study because of the high availability of energetic nutriments (H2, iron oxides and hydroxides) produced in anoxic disposal conditions. Local electrochemical techniques were used for investigating the activity of IRB as a promoter of local corrosion in the presence of H2 as electron donor. A local consumption of H2 by the bacteria has been evidenced and impedance measurements indicate the formation of a thick layer of corrosion products.

  16. Iron bioavailability from cereal products enriched with Pleurotus ostreatus mushrooms in rats with induced anaemia.

    PubMed

    Reguła, Julita; Krejpcio, Zbigniew; Staniek, Halina

    2016-06-02

    Oyster mushroom Pleurotus ostreatus is good source of iron. However, there is a limited data concerning bioavailability of iron from oyster mushroom and also cereal products containing this mushroom. The aim of this study was to assess bioavailability of iron from products with an addition of Pleurotus ostreatus in male rats with anaemia. Investigations were conducted in two stages. In the first stage iron deficiency was developed in rats. For this purpose 6 weeks old 36 male Wistar rats were fed a AIN-93M diet deficient in iron and 6 males received a standard AIN-93M diet. In the second stage of the study the assessment of Fe bioavailability from cereal products enriched with dried Pleurotus ostreatus. After experiment the animals were killed and blood and heart, liver, spleen and kidneys were collected for biochemical tests. Feeding male Wistar rats supplemented with dried Pleurotus ostreatus mushrooms diets resulted in the restitution of the systemic Fe level, as manifested by an increase of the level comparable to the control group for: iron transferrin saturation rate, haemoglobin and mean corpuscular volume. Values of hematocrit, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration in animals fed products supplemented with Pleurotus ostreatus were significantly higher compared to animals fed products with no Fe added. The highest MCV value was recorded when 20% of dried oyster mushrooms were added. Iron levels in the blood serum, the liver and kidneys in animals fed cereal products considerably exceeded values recorded at the beginning of the experiment and were similar to the control values. Product may be a valuable source of iron in the nutrition of individuals with a deficiency of this element, first of all patients with absorption and metabolism disorders, but also may add variety to the traditional daily diet.

  17. PIXE elemental mapping on original manuscripts with an external microbeam. Application to manuscripts damaged by iron-gall ink corrosion

    NASA Astrophysics Data System (ADS)

    Remazeilles, Céline; Quillet, Véronique; Calligaro, Thomas; Claude Dran, Jean; Pichon, Laurent; Salomon, Joseph

    2001-07-01

    Proton-induced X-ray emission (PIXE) mapping and PIXE spot analysis have been performed on three original manuscripts. We observed that the precision of the spot measurements for the analysis of the ink composition is limited by the heterogeneity of the writing. PIXE mapping proved to be a complementary technique which is much more sensitive, and which makes it possible to evaluate the migration of some elements, such as sulphur, iron and calcium around inscriptions.

  18. Modeling the Distribution of Acidity within Nuclear Fuel (UO{sub 2}) Corrosion Product Deposits and Porous Sites

    SciTech Connect

    Cheong, W.J.; Keech, P.G.; Wren, J.C.; Shoesmith, D.W.; Qin, Z.

    2007-07-01

    A model for acidity within pores within corrosion products on anodically-dissolving UO{sub 2} was developed using Comsol Multiphysics 3.2 to complement ongoing electrochemical measurements. It was determined that a depression of pH within pores can be maintained if: electrochemically measured dissolution currents used in the calculations are attenuated to reflect very localized pores; corrosion potentials exceed -250 mV (vs. SCE); and pore depths are >1 {mu}m for 300 mV or >100 {mu}m for -50 mV (vs. SCE). Mixed diffusional-chemical equilibria control is suggested through deviations in the shapes between pH-potential and pH-pore depth plots. (authors)

  19. Production of carbon nano-tubes via CCVD method and their corrosion protection performance in epoxy based coatings

    NASA Astrophysics Data System (ADS)

    Raza, M. A.; Ghauri, F. A.; Awan, M. S.; Farooq, A.; Ahmad, R.

    2016-08-01

    Good yield of carbon products was obtained by catalytic chemical vapor deposition (CCVD) technique using 100-500mg of ferrocene catalyst at temperature of 900 °C and acetylene flow rate of 150-200cc/min. The effects of amount of ferrocene, temperature and hydrocarbons precursors on the yield of carbon nanomaterial's was calculated and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) andenergy- dispersive X-ray spectroscopy (EDS). Good yield of carbon nanomaterials primarily consisted of carbon nanotubes (CNTs) and carbon nanoparticles was obtained. CNTs obtained after purification were dispersed in epoxy resin to produce composite coatings which were coated on stainless steel 316L. The coated stainless steel samples’ corrosion behavior was studied using open circuit potential (OCP), cyclic polarization and electrochemical impedance spectroscopy (EIS) techniques. Results showed that epoxy coating containing 4 wt. % of CNTs offered improved corrosion resistance to stainless steel.

  20. Role of temperature, chlorine, and organic matter in copper corrosion by-product release in soft water.

    PubMed

    Boulay, N; Edwards, M

    2001-03-01

    Soft, low alkalinity drinking waters tend to cause relatively high copper corrosion by-product release in plumbing systems. Long-term tests (6-8 months) in a synthetic, microbially stable soft tap water confirmed that lower pHs and higher temperatures increased copper release to water. Soluble copper release increased at lower temperature and lower pH. Low levels of free chlorine (0.7 mg/L) slightly increased copper release at pH 9.5, in marked contrast to the dramatic reductions in copper release that have been observed in soft waters in which Type III pitting corrosion is occurring. Gum xanthan and sodium alginate produced a microbially unstable water that reduced the pH and DO during stagnation in pipes--these indirect effects far outweighed their possible role in chelation or other modes of direct attack on copper surfaces.