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Sample records for corrosion protective layer

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

    NARCIS (Netherlands)

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

    2007-01-01

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

  2. Corrosion protected, multi-layer fuel cell interface

    Science.gov (United States)

    Feigenbaum, Haim; Pudick, Sheldon; Wang, Chiu L.

    1986-01-01

    An improved interface configuration for use between adjacent elements of a fuel cell stack. The interface is impervious to gas and liquid and provides resistance to corrosion by the electrolyte of the fuel cell. The multi-layer configuration for the interface comprises a non-cupreous metal-coated metallic element to which is film-bonded a conductive layer by hot pressing a resin therebetween. The multi-layer arrangement provides bridging electrical contact.

  3. Corrosion protection

    Science.gov (United States)

    Brown, Donald W.; Wagh, Arun S.

    2003-05-27

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

  4. Monolayers and mixed-layers on copper towards corrosion protection

    Energy Technology Data Exchange (ETDEWEB)

    Sinapi, F. [Fonds pour la Formation a la Recherche dans l' Industrie et dans l' Agriculture, Rue d' Egmont 5, B-1000 Brussels (Belgium); Julien, S.; Auguste, D.; Hevesi, L.; Delhalle, J. [Laboratory of Chemistry and Electrochemistry of Surfaces, University of Namur, FUNDP, Rue de Bruxelles, 61, B-5000 Namur (Belgium); Mekhalif, Z. [Laboratory of Chemistry and Electrochemistry of Surfaces, University of Namur, FUNDP, Rue de Bruxelles, 61, B-5000 Namur (Belgium)], E-mail: zineb.mekhalif@fundp.ac.be

    2008-05-01

    In order to improve the protection abilities of (3-mercaptopropy)trimethoxysilane (MPTS) self-assembled monolayers on copper surfaces, mixed monolayers have been formed successfully by successive immersions in MPTS and in n-dodecanethiol (DT). A newly synthesised molecule, (11-mercaptoundecyl)trimethoxysilane (MUTS), has also been employed to form a thicker organic film on copper surfaces and, thereby, enhance the inhibitory action of the coating. The grafting has been confirmed by X-ray photoelectron spectroscopy (XPS), polarization modulation infrared reflection adsorption spectroscopy (PM-IRRAS) and water contact angle. The protective efficiency of each protective organic film has been evidenced by cyclic voltammetry (CV) and polarization curve measurements (CP). It was shown that the MUTS and unhydrolyzed MPTS/DT films exhibited significant corrosion protection properties.

  5. Corrosion product layers on magnesium alloys AZ31 and AZ61: Surface chemistry and protective ability

    Energy Technology Data Exchange (ETDEWEB)

    Feliu, S., E-mail: sfeliu@cenim.csic.es; Llorente, I.

    2015-08-30

    Highlights: • Surface chemistry of the corrosion product layers on magnesium alloys. • Influence of the type of alloy on the carbonate surface enrichment. • Relation between surface composition and protection properties. - Abstract: This paper studies the chemical composition of the corrosion product layers formed on magnesium alloys AZ31 and AZ61 following immersion in 0.6 M NaCl, with a view to better understanding their protective action. Relative differences in the chemical nature of the layers were quantified by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive analysis of X-ray (EDX) and low-angle X-ray diffraction (XRD). Corrosion behavior was investigated by Electrochemical Impedance Spectroscopy (EIS) and hydrogen evolution measurement. An inhibitive effect from the corrosion product layers was observed from EIS, principally in the case of AZ31, as confirmed by hydrogen evolution tests. A link was found between carbonate enrichment observed by XPS in the surface of the corrosion product layer, concomitant with the increase in the protective properties observed by EIS.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cook, D.C. [Old Dominion University, Department of Physics (United States); Oh, S.J. [Pohang University of Science and Technology, Pohang, Department of Materials Science and Engineering (Korea, Republic of); Balasubramanian, R. [Old Dominion University, Department of Physics (United States); Yamashita, M. [Himeji Institute of Technology, Department of Mechanical Engineering (Japan)

    1999-11-15

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

  7. Protection against corrosion of magnesium alloys with both conversion layer and sol–gel coating

    OpenAIRE

    2013-01-01

    International audience; The anticorrosion performances of a system consisting of a phosphate based conversion layer and a hybrid sol–gel coating have been evaluated for the magnesium alloy Elektron21. The lone sol–gel coating affords a significant protection of the magnesium substrate. However, the presence of an intermediate conversion layer is presumed to improve the corrosion resistance of the system. The surface morphology of the protection coatings was characterized by optical microscopy...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-05-31

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

  9. Thermal spraying of corrosion protection layers in biogas plants; Erzeugung von Korrosionsschutzschichten fuer Bioenergieanlagen mittels Thermischen Spritzens

    Energy Technology Data Exchange (ETDEWEB)

    Crimmann, P.; Dimaczek, G.; Faulstich, M. [ATZ Entwicklungszentrum, Sulzbach-Rosenberg (Germany)

    2004-07-01

    Corrosion in plants for the energetic conversion of biomass is a severe problem that often causes premature damage of components. Thermal spraying is a process for the creation of corrosion protection layer. An advantage of thermal spraying is that as well as each material can be used as layer material. First practical results demonstrated that thermal spraying has the potential to create coatings to protect components against high temperature corrosion as well as biocorrosion. Layer materials are for example nickel base alloys (high temperature corrosion) and titan alloys (biocorrosion). Further investigations are necessary in order to examine whether cost-efficient coatings also contribute to the corrosion protection (e.g. polymer materials against biocorrosion). (orig.)

  10. A new double layer epoxy coating for corrosion protection of Petroleum Equipments

    Directory of Open Access Journals (Sweden)

    Maher A. El Sockarya

    2014-11-01

    Full Text Available Homogeneous epoxy coating containing polymer nanocomposite (PNC was successfully synthesized and applied on carbon steel substrates by room temperature curing of fully mixed epoxy slurry. (PNC containing both ZNO nanoparticles and epoxy hyper branched polymer (EHBP, a new double layer thin film which comprises ZNO-epoxy as a primer coat and ZNO-EHBP-epoxy as a top coat offers better corrosion protection compared to the purely inorganic ZNO-epoxy coating and hybrid ZNO-EHBP-epoxy coating. Chemical structures of synthesized compounds were confirmed by FTIR, H1NMR spectroscopy and GPC. The surface morphology and phase structure of the produced Zno nanoparticles were characterized by scanning electron microscopy SEM, transmission electron microscopy TEM and X-ray diffraction. Chemical resistance of theses coatings to NaOH and HCL was investigated. The effect of incorporating polymer nanocomposite and new double layer coating on corrosion resistance of epoxy coated steel was investigated by salt spray test.

  11. Metallic corrosion processes reactivation sustained by iron-reducing bacteria: Implication on long-term stability of protective layers

    Science.gov (United States)

    Esnault, L.; Jullien, M.; Mustin, C.; Bildstein, O.; Libert, M.

    In deep geological environments foreseen for the disposal of radioactive waste, metallic containers will undergo anaerobic corrosion. In this context, the formation of corrosion products such as magnetite may reduce the rate of corrosion processes through the formation of a protective layer. This study aims at determining the direct impact of iron-reducing bacteria (IRB) activity on the stability of corrosion protective layers. Batch experiments investigating iron corrosion processes including the formation of secondary magnetite and its subsequent alteration in the presence of IRB show the bacteria ability to use structural Fe(III) for respiration which leads to the sustainment of a high corrosion rate. With the bio-reduction of corrosion products such as magnetite, and H 2 as electron donor, IRB promote the reactivation of corrosion processes in corrosive environments by altering the protective layer. This phenomenon could have a major impact on the long-term stability of metallic compounds involved in multi-barrier system for high-level radioactive waste containment.

  12. Hybrid layers deposited by an atmospheric pressure plasma process for corrosion protection of galvanized steel.

    Science.gov (United States)

    Del Frari, D; Bour, J; Bardon, J; Buchheit, O; Arnoult, C; Ruch, D

    2010-04-01

    Finding alternative treatments to reproduce anticorrosion properties of chromated coatings is challenging since both physical barrier and self-healing effects are needed. Siloxane based treatments are known to be a promising way to achieve physical barrier coatings, mainly plasma polymerized hexamethyldisiloxane (ppHMDSO). In addition, it is known that cerium-based coatings can also provide corrosion protection of metals by means of self-healing effect. In this frame, innovative nanoAlCeO3/ppHMDSO layers have thus been deposited and studied. These combinations allow to afford a good physical barrier effect and active properties. Liquid siloxane and cerium-based particles mixture is atomized and introduced as precursors into a carrier gas. Gas mixture is then injected into an atmospheric pressure dielectric barrier discharge (DBD) where plasma polymerization of the siloxane precursor occurs. The influence of cerium concentration on the coating properties is investigated: coating structure and topography have been studied by scanning electron microscopy (SEM) and interferometry, and corrosion resistance of these different coatings is compared by electrochemistry techniques: polarization curves and electrochemical impedance spectroscopy (EIS). Potential self-healing property afforded by cerium in the layer was studied by associating EIS measurements and nanoscratch controlled damaging. Among the different combinations investigated, mixing of plasma polymerized HMDSO and AICeO3 nanoparticles seems to give promising results with a good physical barrier and interesting electroactive properties. Indeed, corrosion currents measured on such coatings are almost as low as those measured with the chromated film. Combination of nanoscratch damaging of layers with EIS experiments to investigate self-healing also allow to measure the active protection property of such layers.

  13. Corrosion protection by anaerobiosis.

    Science.gov (United States)

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

    2001-01-01

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

  14. Atomic Layer Deposited Coatings on Nanowires for High Temperature Water Corrosion Protection.

    Science.gov (United States)

    Yersak, Alexander S; Lewis, Ryan J; Liew, Li-Anne; Wen, Rongfu; Yang, Ronggui; Lee, Yung-Cheng

    2016-11-30

    Two-phase liquid-cooling technologies incorporating micro/nanostructured copper or silicon surfaces have been established as a promising thermal management solution to keep up with the increasing power demands of high power electronics. However, the reliability of nanometer-scale features of copper and silicon in these devices has not been well investigated. In this work, accelerated corrosion testing reveals that copper nanowires are not immune to corrosion in deaerated pure hot water. To solve this problem, we investigate atomic layer deposition (ALD) TiO2 coatings grown at 150 and 175 °C. We measured no difference in coating thickness for a duration of 12 days. Using a core/shell approach, we grow ALD TiO2/Al2O3 protective coatings on copper nanowires and demonstrate a preservation of nanoengineered copper features. These studies have identified a critical reliability problem of nanoscale copper and silicon surfaces in deaerated, pure, hot water and have successfully demonstrated a reliable solution using ALD TiO2/Al2O3 protective coatings.

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

    OpenAIRE

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

    2012-01-01

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

  16. Coating Layer and Corrosion Protection Characteristics in Sea Water with Various Thermal Spray Coating Materials for STS304

    Science.gov (United States)

    Kim, Seong-Jong; Woo, Yong-Bin

    We investigated the optimal method of application and the anticorrosive abilities of Zn, Al, and Zn + 15%Al spray coatings in protecting stainless steel 304 (STS304) in sea water. If a defect such as porosity or an oxide layer, causes STS304 to be exposed to sea water, and the thermal spray coating material will act as the cathode and anode, respectively. The Tafel experiments revealed that Al-coated specimens among applied coating methods had the lowest corrosion current densities. As the corrosion potential decreases with increasing corrosion current density, we estimated the characteristics and lifetime of the protective thermal spray coating layer in the galvanic cell formed by the thermal spray coating layer and STS304.

  17. Emeraldine base as corrosion protective layer on aluminium alloy AA5182, effect of the surface microstructure

    DEFF Research Database (Denmark)

    Cecchetto, L; Ambat, Rajan; Davenport, A.J.

    2007-01-01

    AA5182 aluminium alloy cold rolled samples were coated by thin Wlms of emeraldine base (EB) obtained from a 5% solution in N-methylpyrrolidinone. Accelerated corrosion tests prove this coating very eVective for corrosion protection of aluminium alloys in neutral environment. This study underlines......: • a weak redox activity of the polymer which passivate the metal, • a proton involving self-healing process taking place at the polymer–metal interface, which contributes to delay local acidiWcation in Wrst steps of corrosion on EB coated aluminium surfaces....

  18. Corrosion protection of fluorzirconate glasses coated by a layer of surface modified tin oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hammer, P. [Instituto de Quimica /UNESP, Departamento de Fisico-Quimica, P.O. Box 355, CEP 14801-970, Araraquara, SP (Brazil)]. E-mail: peter@iq.unesp.br; Rizzato, A.P. [Instituto de Quimica /UNESP, Departamento de Fisico-Quimica, P.O. Box 355, CEP 14801-970, Araraquara, SP (Brazil); Alvarez, F. [Instituto de Fisica ' Gleb Wataghin' , Universidade Estadual de Campinas, Unicamp, 13083-970, Campinas, SP (Brazil); Landers, R. [Instituto de Fisica ' Gleb Wataghin' , Universidade Estadual de Campinas, Unicamp, 13083-970, Campinas, SP (Brazil); Pulcinelli, S.H. [Instituto de Quimica /UNESP, Departamento de Fisico-Quimica, P.O. Box 355, CEP 14801-970, Araraquara, SP (Brazil); Santilli, C.V. [Instituto de Quimica /UNESP, Departamento de Fisico-Quimica, P.O. Box 355, CEP 14801-970, Araraquara, SP (Brazil)

    2006-04-28

    The protection efficiency against water corrosion of fluorozirconate glass, ZBLAN, dip-coated by nanocrystalline tin oxide film containing the organic molecule Tiron (registered) was investigated by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The chemical bonding structure of the surface region and morphology were studied before and after two water exposure periods of 5 and 30 min. The results of the analysis for the as-grown sample revealed a SnO{sub 1.6} phase containing carbon and sulfur, related to Tiron (registered) , and traces of elements related to ZBLAN (Zr, F, Ba). This fact and the clear evidence of the presence of tin oxifluoride specie (SnO {sub x}F {sub y}) indicates a diffusion of the glass components into the porous coating. After water exposure, the increase of the oxygen concentration accompanied by a strong increase of Zr, F, Ba and Na content is interpreted as filling of the nanopores of the film by glass compounds. The formation of a compact protective layer is supported by the morphological changes observed by AFM.

  19. Interface control of atomic layer deposited oxide coatings by filtered cathodic arc deposited sublayers for improved corrosion protection

    Energy Technology Data Exchange (ETDEWEB)

    Härkönen, Emma, E-mail: emma.harkonen@helsinki.fi [Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland); Tervakangas, Sanna; Kolehmainen, Jukka [DIARC-Technology Inc., Espoo (Finland); Díaz, Belén; Światowska, Jolanta; Maurice, Vincent; Seyeux, Antoine; Marcus, Philippe [Laboratoire de Physico-Chimie des Surfaces, CNRS (UMR 7075) – Chimie ParisTech (ENSCP), F-75005 Paris (France); Fenker, Martin [FEM Research Institute, Precious Metals and Metals Chemistry, D-73525 Schwäbisch Gmünd (Germany); Tóth, Lajos; Radnóczi, György [Research Centre for Natural Sciences HAS, (MTA TKK), Budapest (Hungary); Ritala, Mikko [Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland)

    2014-10-15

    Sublayers grown with filtered cathodic arc deposition (FCAD) were added under atomic layer deposited (ALD) oxide coatings for interface control and improved corrosion protection of low alloy steel. The FCAD sublayer was either Ta:O or Cr:O–Ta:O nanolaminate, and the ALD layer was Al{sub 2}O{sub 3}–Ta{sub 2}O{sub 5} nanolaminate, Al{sub x}Ta{sub y}O{sub z} mixture or graded mixture. The total thicknesses of the FCAD/ALD duplex coatings were between 65 and 120 nm. Thorough analysis of the coatings was conducted to gain insight into the influence of the FCAD sublayer on the overall coating performance. Similar characteristics as with single FCAD and ALD coatings on steel were found in the morphology and composition of the duplex coatings. However, the FCAD process allowed better control of the interface with the steel by reducing the native oxide and preventing its regrowth during the initial stages of the ALD process. Residual hydrocarbon impurities were buried in the interface between the FCAD layer and steel. This enabled growth of ALD layers with improved electrochemical sealing properties, inhibiting the development of localized corrosion by pitting during immersion in acidic NaCl and enhancing durability in neutral salt spray testing. - Highlights: • Corrosion protection properties of ALD coatings were improved by FCAD sublayers. • The FCAD sublayer enabled control of the coating-substrate interface. • The duplex coatings offered improved sealing properties and durability in NSS. • The protective properties were maintained during immersion in a corrosive solution. • The improvements were due to a more ideal ALD growth on the homogeneous FCAD oxide.

  20. Composition and Morphology of Product Layers in the Steel/Cement Paste Interface in Conditions of Corrosion and Cathodic Protection in Reinforced Concrete

    NARCIS (Netherlands)

    Koleva, D.A.; Van Breugel, K.; De Wit, J.H.W.; Fraaij, A.L.A.; Boshkov, N.

    2007-01-01

    The present study explores the formation of corrosion products on the steel surface in reinforced concrete in conditions of corrosion and subsequent transformation of these layers in conditions of cathodic protection (CP). Of particular interest was to investigate if the introduced pulse CP (as cost

  1. XPS study on water corrosion of fluorzirconate glasses and their protection by a layer of surface modified tin dioxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hammer, P. [Sao Paulo State University, Institute of Chemistry, 14801-970 Araraquara, SP (Brazil)], E-mail: peter@iq.unesp.br; Rizzato, A.P. [Rhodia Poliamida e Especialidades, Fazenda Sao Francisco, 07 13140-000 Paulinia, SP (Brazil); Pulcinelli, S.H.; Santilli, C.V. [Sao Paulo State University, Institute of Chemistry, 14801-970 Araraquara, SP (Brazil)

    2007-05-15

    The surface corrosion process associated with the hydrolysis of fluorozirconate glass, ZBLAN (53ZrF{sub 4}, 20BaF{sub 2}, 20NaF, 4LaF{sub 2}, 3AlF{sub 3}), and the corrosion protection efficiency of a nanocrystalline transparent SnO{sub 2} layer were investigated by X-ray photoelectron spectroscopy. The tin oxide film was deposited by the sol-gel dip-coating process in the presence of Tiron as particle surface modifier agent. The chemical bonding structure and composition of the surface region of coated and non-coated ZBLAN were studied before water contact and after different immersion periods (5-30 min). In contrast to the effects occurring for non-coated glass, where the surface undergoes a rapid selective dissolution of the most soluble species inducing the formation of a new surface phase consisting of stable zirconium oxyfluoride, barium fluoride and lanthanum fluoride species, the results for the SnO{sub 2}-coated glass showed that the hydrolytic attack induces a filling of the film nanopores by dissolved glass material and the formation of tin oxyfluoride and zirconium oxyfluoride species. This process results in a modified film, which acts as a hermetic diffusion barrier protecting efficiently the glass surface.

  2. Smart Coatings for Corrosion Protection

    Science.gov (United States)

    Calle, Luz Marina; Li, Wendy; Buhrow, Jerry W.; Johnsey, Marissa N.

    2016-01-01

    Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. It is essential to detect corrosion when it occurs, and preferably at its early stage, so that action can be taken to avoid structural damage or loss of function. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it.

  3. Laser-controllable coatings for corrosion protection.

    Science.gov (United States)

    Skorb, Ekaterina V; Skirtach, Andre G; Sviridov, Dmitry V; Shchukin, Dmitry G; Möhwald, Helmuth

    2009-07-28

    We introduce a novel and versatile approach to the corrosion protection by use of "smart" laser-controllable coating. The main advantage of the proposed technique is that one could terminate the corrosion process by very intensive healing after an appearance of corrosion centers using local laser irradiation. It is also shown that by applying a polyelectrolyte shell with noble metal particles over the mesoporous titania and silica via layer-by-layer assembly it is possible to fabricate micro- and nanoscaled reservoirs, which, being incorporated into the zirconia-organosilica matrix, are responsible for the ability of laser-driven release of the loaded materials (e.g., corrosion inhibitor). Furthermore, the resultant films are highly adhesive and could be easily deposited onto different metallic substrates. Laser-mediated remote release of incorporated corrosion inhibitor (benzotriazole) from engineered mesoporous containers with silver nanoparticles in the container shell is observed in real time on single and multicontainer levels.

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

    Directory of Open Access Journals (Sweden)

    Ayman M. Atta

    2014-07-01

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

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

    Science.gov (United States)

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

    2014-07-17

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

  6. Numerical simulation of a metal corrosion for a point defect for a organic protection layer; Simulations numeriques de la corrosion d'un metal au niveau d'un defaut ponctuel d'une couche organique de protection

    Energy Technology Data Exchange (ETDEWEB)

    Vautrin-Ul, Ch.; Chausse, A. [Evry Univ., Laboratoire Analyses et Environnement, UMR 8587-CEA-CNRS, 91(France); Stafiej, J. [Institute of Physical Chemistry, Polish Academy of Sciences, Varsovie (Poland); Badiali, J.P. [Universite Pierre et Marie Curie, LECA-ERI, UMR 7575ENSCP, 75 - Paris (France)

    2005-07-01

    The safety of radioactive wastes disposal requires a big knowledge on their aging facing a corrosive environment. The corrosion is a complex phenomenon which implies many processes bound to the physic and the chemistry of the system. This approach proposes, from a little number of simple processes, numerical simulation which will define theses complex phenomenon. The presented model is a 2 dimension model at a mesoscopic scale and based on cellular automates. It allows the simulation of a metal evolution, protected by a polymer layer and in contact at one point with a corrosive media at a defect of the layer. (A.L.B.)

  7. CORROSION PROTECTION OF ALUMINUM

    Science.gov (United States)

    Dalrymple, R.S.; Nelson, W.B.

    1963-07-01

    Treatment of aluminum-base metal surfaces in an autoclave with an aqueous chromic acid solution of 0.5 to 3% by weight and of pH below 2 for 20 to 50 hrs at 160 to 180 deg C produces an extremely corrosion-resistant aluminum oxidechromium film on the surface. A chromic acid concentration of 1 to 2% and a pH of about 1 are preferred. (D.C.W.)

  8. Corrosion protection of silver-based telescope mirrors using evaporated anti-oxidation overlayers and aluminum oxide films by atomic layer deposition

    Science.gov (United States)

    Fryauf, David M.; Phillips, Andrew C.; Kobayashi, Nobuhiko P.

    2016-09-01

    An urgent demand remains in astronomy for high-reflectivity silver mirrors that can withstand years of exposure in observatory environments. The University of California Observatories Astronomical Coatings Lab has undertaken development of protected silver coatings suitable for telescope mirrors that maintain high reflectivity at wavelengths from 340 nm through the mid-infrared spectrum. We present results on superior protective layers of transparent dielectrics produced by evaporation and atomic layer deposition. Several novel coating recipes have been developed with ion-assisted electron beam deposition (IAEBD) of various fluorides, oxides, and nitrides in combination with conformal layers of aluminum oxide (AlOx) deposited by ALD using trimethylaluminum as a metal precursor and water vapor as a reactant. Extending on our previous results demonstrating the superior durability of ALD-based AlOx top barrier layers over conventionally-deposited AlOx, this work investigates the effects on mirror barrier durability comparing different anti-oxidation materials on Ag with an identical AlOx top barrier layer deposited by ALD. Samples of coating recipes with different anti-oxidation layers undergo aggressive environmental testing, including high temperature/high humidity (HTHH), in which samples are exposed to an environment of 80% humidity at 80°C for ten days in a simple test set-up. While most samples show fairly successful endurance after HTHH testing, visible results suggest that MgAl2O4, Al2O3, and AlN anti-oxidation layers offer enhanced robust protection against chemical corrosion and moisture in an accelerated aging environment, which is attributed to superior adhesion and intermolecular bonding between the Al-based anti-oxidation layers and the AlOx top barrier layer. Mirror samples are further characterized by reflectivity/absorption before and after deposition of oxide coatings. We also show that the performance of the ALD-AlOx barrier layer depends in part

  9. Mechanism of Pitting Corrosion Protection of Metals and Alloys

    OpenAIRE

    Vladimir Alexandrovich Grachev; Andrei Evgenievich Rozen; Gennadii Vasilievich Kozlov; Andrei Andreievich Rozen

    2016-01-01

    In this article authors set out a principle of pitting corrosion protection, suggested a new class of multilayer materials with high corrosion resistance. They substantiated the choice of the layers for the multilayer material designed for exploitation in oxidizing and non-oxidizing environment. The sphere of application of the multilayer materials was defined.

  10. Corrosion protection and control using nanomaterials

    CERN Document Server

    Cook, R

    2012-01-01

    This book covers the use of nanomaterials to prevent corrosion. The first section deals with the fundamentals of corrosion prevention using nanomaterials. Part two includes a series of case studies and applications of nanomaterials for corrosion control.$bCorrosion is an expensive and potentially dangerous problem in many industries. The potential application of different nanostructured materials in corrosion protection, prevention and control is a subject of increasing interest. Corrosion protection and control using nanomaterials explores the potential use of nanotechnology in corrosion control. The book is divided into two parts. Part one looks at the fundamentals of corrosion behaviour and the manufacture of nanocrystalline materials. Chapters discuss the impact of nanotechnology in reducing corrosion cost, and investigate the influence of various factors including thermodynamics, kinetics and grain size on the corrosion behaviour of nanocrystalline materials. There are also chapters on electrodeposition ...

  11. 49 CFR 193.2625 - Corrosion protection.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Corrosion protection. 193.2625 Section 193.2625...: FEDERAL SAFETY STANDARDS Maintenance § 193.2625 Corrosion protection. (a) Each operator shall determine which metallic components could, unless corrosion is controlled, have their integrity or...

  12. Corrosion Protection of Electrically Conductive Surfaces

    OpenAIRE

    Jian Song; Liangliang Wang; Andre Zibart; Christian Koch

    2012-01-01

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

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

    Science.gov (United States)

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

    2012-11-01

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

  14. Migrating corrosion inhibitor protection of concrete

    Energy Technology Data Exchange (ETDEWEB)

    Bjegovic, D.; Miksic, B.

    1999-11-01

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

  15. Catalysts, Protection Layers, and Semiconductors

    DEFF Research Database (Denmark)

    Chorkendorff, Ib

    2015-01-01

    Hydrogen is the simplest solar fuel to produce and in this presentation we shall give a short overview of the pros and cons of various tandem devices [1]. The large band gap semiconductor needs to be in front, but apart from that we can chose to have either the anode in front or back using either...... acid or alkaline conditions. Since most relevant semiconductors are very prone to corrosion the advantage of using buried junctions and using protection layers offering shall be discussed [2-4]. Next we shall discuss the availability of various catalysts for being coupled to these protections layers...... and how their stability may be evaluated [5, 6]. Examples of half-cell reaction using protection layers for both cathode and anode will be discussed though some of recent examples under both alkaline and acidic conditions. Si is a very good low band gap semiconductor and by using TiO2 as a protection...

  16. Ozone Layer Protection

    Science.gov (United States)

    ... Search Search Ozone Layer Protection Share Facebook Twitter Google+ Pinterest Contact Us Ozone Layer Protection Welcome to ... Managing Refrigerant Emissions Stationary Refrigeration and Air Conditioning Car and Other Mobile Air Conditioning GreenChill Partnership Responsible ...

  17. Remote computer monitors corrosion protection system

    Energy Technology Data Exchange (ETDEWEB)

    Kendrick, A.

    Effective corrosion protection with electrochemical methods requires some method of routine monitoring that provides reliable data that is free of human error. A test installation of a remote computer control monitoring system for electrochemical corrosion protection is described. The unit can handle up to six channel inputs. Each channel comprises 3 analog signals and 1 digital. The operation of the system is discussed.

  18. Corrosion Protection of Electrically Conductive Surfaces

    Directory of Open Access Journals (Sweden)

    Jian Song

    2012-11-01

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

  19. Corrosion Protection of Steels by Conducting Polymer Coating

    Directory of Open Access Journals (Sweden)

    Toshiaki Ohtsuka

    2012-01-01

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

  20. Influence of Bath Composition at Acidic pH on Electrodeposition of Nickel-Layered Silicate Nanocomposites for Corrosion Protection

    Directory of Open Access Journals (Sweden)

    Jeerapan Tientong

    2013-01-01

    Full Text Available Nickel-layered silicates were electrochemically deposited from acidic bath solutions. Citrate was used as a ligand to stabilize nickel (II ions in the plating solution. The silicate, montmorillonite, was exfoliated by stirring in aqueous solution over 24 hours. The plating solutions were analyzed for zeta-potential, particle size, viscosity, and conductivity to investigate the effects of the composition at various pHs. The solution particles at pH 2.5 (−22.2 mV and pH 3.0 (−21.9 mV were more stable than at pH 1.6 (−10.1 mV as shown by zeta-potential analysis of the nickel-citrate-montmorillonite plating solution. Ecorr for the films ranged from −0.32 to −0.39 V with varying pH from 1.6 to 3.0. The films were immersed in 3.5% NaCl and the open circuit potential monitored for one month. The coatings deposited at pH 3.0 were stable 13 days longer in the salt solution than the other coatings. X-ray diffraction showed a change in the (111/(200 ratio for the coatings at the various pHs. The scanning electron microscopy and hardness results also support that the electrodeposition of nickel-montmorillonite at pH 3.0 (234 GPa had improved hardness and morphology compared to pH 2.5 (174 GPa and pH 1.6 (147 GPa.

  1. Mesoporous silica nanoparticles for active corrosion protection.

    Science.gov (United States)

    Borisova, Dimitriya; Möhwald, Helmuth; Shchukin, Dmitry G

    2011-03-22

    This work presents the synthesis of monodisperse, mesoporous silica nanoparticles and their application as nanocontainers loaded with corrosion inhibitor (1H-benzotriazole (BTA)) and embedded in hybrid SiOx/ZrOx sol-gel coating for the corrosion protection of aluminum alloy. The developed porous system of mechanically stable silica nanoparticles exhibits high surface area (∼1000 m2·g(-1)), narrow pore size distribution (d∼3 nm), and large pore volume (∼1 mL·g(-1)). As a result, a sufficiently high uptake and storage of the corrosion inhibitor in the mesoporous nanocontainers was achieved. The successful embedding and homogeneous distribution of the BTA-loaded monodisperse silica nanocontainers in the passive anticorrosive SiOx/ZrOx film improve the wet corrosion resistance of the aluminum alloy AA2024 in 0.1 M sodium chloride solution. The enhanced corrosion protection of this newly developed active system in comparison to the passive sol-gel coating was observed during a simulated corrosion process by the scanning vibrating electrode technique (SVET). These results, as well as the controlled pH-dependent release of BTA from the mesoporous silica nanocontainers without additional polyelectrolyte shell, suggest an inhibitor release triggered by the corrosion process leading to a self-healing effect.

  2. Silica nanocontainers for active corrosion protection

    Science.gov (United States)

    Maia, Frederico; Tedim, João; Lisenkov, Aleksey D.; Salak, Andrei N.; Zheludkevich, Mikhail L.; Ferreira, Mário G. S.

    2012-02-01

    Novel self-healing protective coatings with nanocontainers of corrosion inhibitors open new opportunities for long-term anticorrosion protection of different metallic materials. In this paper a new type of functional nanoreservoir based on silica nanocapsules (SiNC) synthesized and loaded with corrosion inhibitor 2-mercaptobenzothiazole (MBT) in a one-stage process is reported for the first time. Unlike conventional mesoporous silica nanoparticles, SiNC possess an empty core and shell with gradual mesoporosity, arising from the particular conditions of the synthetic route adopted, which confers significant loading capacity and allows prolonged and stimuli-triggered release of the inhibiting species. The kinetics of inhibitor release was studied at different pH values and concentrations of NaCl. The results show a clear dependence of the release profiles on corrosion relevant triggers such as pH and Cl- concentration. When SiNC loaded with MBT are dispersed in NaCl solution, there is a significant decrease of the corrosion activity on aluminium alloy 2024. More importantly, when SiNC-MBT is added to a conventional water-based coating formulation, the modified coating hampers corrosion activity at the metal interface, better than in the case of direct addition of corrosion inhibitor. Furthermore, self-healing is observed before and after artificially inflicting defects in the modified coatings. As a result, the developed nanocontainers show high potential to be used in new generation of active protective coatings.

  3. Corrosion protection with eco-friendly inhibitors

    Science.gov (United States)

    Shahid, Muhammad

    2011-12-01

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

  4. Durable Corrosion Resistance of Copper Due to Multi-Layer Graphene

    Directory of Open Access Journals (Sweden)

    Abhishek Tiwari

    2017-09-01

    Full Text Available Ultra-thin graphene coating has been reported to provide considerable resistance against corrosion during short-term exposures, however, there is great variability in the corrosion resistance due to graphene coating in different studies. It may be possible to overcome the problem of hampered corrosion protection ability of graphene that is caused due to defective single layer graphene by applying multilayer graphene. Systematic electrochemical characterization showed that the multilayer graphene coating developed in the study provided significant corrosion resistance in a chloride solution and the corrosion resistance was sustained for long durations (~400 h, which is attributed to the multilayer graphene.

  5. Corrosion protective coating for metallic materials

    Science.gov (United States)

    Buchheit, Rudolph G.; Martinez, Michael A.

    1998-01-01

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

  6. Defects Mediated Corrosion in Graphene Coating Layer.

    Science.gov (United States)

    Lei, Jincheng; Hu, Yaowu; Liu, Zishun; Cheng, Gary J; Zhao, Kejie

    2017-04-05

    Mixed results were reported on the anticorrosion of graphene-coated metal surfaces-while graphene serves as an effective short-term barrier against corrosion and oxidation due to its low permeability to gases, the galvanic cell between graphene and the metal substrate facilitates extensive corrosion in the long run. Defects in the graphene layer provide pathways for the permeation of oxidizing species. We study the role of defects in graphene in the anticorrosion using first-principles theoretical modeling. Experiments in the highly reactive environment indicate that the oxidized products primarily distribute along the grain boundaries of graphene. We analyze the thermodynamics of the absorption of S and O on the grain boundaries of graphene on the basis of density functional theory. The insertion of S and O at the vacancy sites is energetically favorable. The interstitial impurities facilitate structural transformation of graphene and significantly decrease the mechanical strength of the graphene layer. Furthermore, the presence of the interstitial S and O reduces the chemical stability of graphene by enhancing the formation of vacancies and promoting dispersive growth of corrosive reactants along the grain boundaries.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

  8. Self-Healing Corrosion Protective Sol-Gel Coatings

    NARCIS (Netherlands)

    Abdolah Zadeh, M.

    2016-01-01

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

  9. Self-Healing Corrosion Protective Sol-Gel Coatings

    NARCIS (Netherlands)

    Abdolah Zadeh, M.

    2016-01-01

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

  10. Protection of Steel Corrosion in Concrete Members by the Combination of Galvanic Anode and Nitrite Penetration

    OpenAIRE

    Minobu Aoyama; Shinichi Miyazato; Mitsunori Kawamura

    2014-01-01

    Chloride induced-corrosion of steel bars in concrete can make cracks and exfoliation in near-surface regions in reinforced concrete structures. In this paper, we described the basic concept and practice of steel bars corrosion protection method by the combination of galvanic anode (zinc wire) and the penetration of nitrite ions from mortar layers containing a large amount of lithium nitrite.

  11. Corrosion behaviors of arc spraying single and double layer coatings in simulated Dagang soil solution

    Institute of Scientific and Technical Information of China (English)

    LIN Bi-lan; LU Xin-ying; LI Long

    2009-01-01

    Three kinds of single layer coatings of Zn,Zn15Al,316L stainless steel and two kinds of double layer coatings with inner layer of Zn or Zn15Al and outer layer of 316L stainless steel by arc spraying were developed to protect the metal ends of prestressed high-strength concrete (PHC) pipe piles against soil corrosion.The corrosion behaviors of the coated Q235 steel samples in the simulated Dagang soil solution were investigated by potentiodynamic polarization,electrochemical impedance spectroscopy (EIS) and natural immersion tests.The results show that the corrosion of the matrix Q235 steel is effectively inhibited by Zn,Zn15Al,Zn+316L and Zn15Al+316L coatings.The corrosion rate value of Zn15Al coated samples is negative.The corrosion products on Zn and Zn15Al coated samples are compact and firm.The corrosion resistance indexes of both Zn and Zn15Al coated samples are improved significantly with corrosion time,and the latter are more outstanding than the former.But the corrosion resistance of 316L coated samples is decreased quickly with the increase in immersion time.When the coatings are sealed with epoxy resin,the corrosion resistance of the coatings will be enhanced significantly.

  12. Trends in the automotive paint industry for corrosion protection

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-07-01

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

  13. Self-Healing Corrosion Protective Sol-Gel Coatings

    OpenAIRE

    Abdolah Zadeh, M.

    2016-01-01

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

  14. Molybdate Coatings for Protecting Aluminum Against Corrosion

    Science.gov (United States)

    Calle, Luz Marina; MacDowell, Louis G.

    2005-01-01

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

  15. Effect of Flow Velocity on Corrosion Rate and Corrosion Protection Current of Marine Material

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seong Jong [Kunsan National University, Kunsan (Korea, Republic of); Han, Min Su; Jang, Seok Ki; Kim, Seong Jong [Mokpo National Maritime University, Mokpo (Korea, Republic of)

    2015-10-15

    In spite of highly advanced paint coating techniques, corrosion damage of marine metal and alloys increase more and more due to inherent micro-cracks and porosities in coatings formed during the coating process. Furthermore, flowing seawater conditions promote the breakdown of the protective oxide of the materials introducing more oxygen into marine environments, leading to the acceleration of corrosion. Various corrosion protection methods are available to prevent steel from marine corrosion. Cathodic protection is one of the useful corrosion protection methods by which the potential of the corroded metal is intentionally lowered to an immune state having the advantage of providing additional protection barriers to steel exposed to aqueous corrosion or soil corrosion, in addition to the coating. In the present investigation, the effect of flow velocity was examined for the determination of the optimum corrosion protection current density in cathodic protection as well as the corrosion rate of the steel. It is demonstrated from the result that the material corrosion under dynamic flowing conditions seems more prone to corrosion than under static conditions.

  16. Graphene coatings for protection against microbiologically induced corrosion

    Science.gov (United States)

    Krishnamurthy, Ajay

    Microbiologically induced corrosion (MIC) is a special form of electrochemical corrosion where micro-organisms affect the local environmental conditions at the metal-electrolyte interface by forming a stable biofilm. The biofilm introduces localized concentration cells, which accelerate the electrochemical corrosion rates. MIC has been found to affect many industrial systems such as sewage waste water pipes, heat exchangers, ships, underwater pipes etc. It has been traditionally eradicated by physical, biochemical and surface protection methods. The cleaning methods and the biocidal deliveries are required periodically and don't provide a permanent solution to the problem. Further, the use of biocides has been harshly criticized by environmentalists due to safety concerns associated with their usage. Surface based coatings have their own drawback of rapid degradation under harsh microbial environments. This has led to the exploration of thin, robust, inert, conformal passivation coatings for the protection of metallic surfaces from microbiologically induced corrosion. Graphene is a 2D arrangement of carbon atoms in a hexagonal honeycomb lattice. The carbon atoms are bonded to one another by sp2 hybridization and each layer of the carbon ring arrangement spans to a thickness of less than a nm. Due to its unique 2D arrangement of carbon atoms, graphene exhibits interesting in-plane and out of plane properties that have led to it being considered as the material for the future. Its excellent thermal, mechanical, electrical and optical properties are being explored in great depth to understand and realize potential applications in various technological realms. Early studies have shown the ability of bulk and monolayer graphene to protect metallic surfaces from air oxidation and solution based galvanic corrosion processes for short periods. However, the role of graphene in resisting MIC is yet to be determined, particularly over the long time spans characteristic of

  17. High Corrosion-Resistance Double-Layer Ni-P Coating on Steels

    Institute of Scientific and Technical Information of China (English)

    JIANG Hai; LIU Xian-li; JIANG Zhang-hao; LI Guang-yu; LIAN Jian-she; GU Chang-dong

    2004-01-01

    Double-layer Ni-P alloy coating with a thickness about 20 μm and different Ni-P layers was prepared by electroless deposition and its corrosion resistance was studied. The microstructure and corrosion-resistance of the coatings were analyzed by SEM, XRD, electrochemical polarization measurements and salt spray tests. The salt spray tests showed that the double-layer coating exhibits better corrosion resistance. The time of the emergence of the first red rust spot on the coating surface can reach 384 hours, and the gray rusts were firstly emergered during the salt spray tests. The electrochemical analysis revealed that the difference in the corrosion potential between the double layers plays a very important role in protecting the substrate from rusting.

  18. Formation Characteristic of CO2 Corrosion Product Layer of P110 Steel Investigated by SEM and Electrochemical Techniques

    Institute of Scientific and Technical Information of China (English)

    ZHAO Guo-xian; LU Xiang-hong; XIANG Jian-min; HAN Yong

    2009-01-01

    Formation characteristic of CO2 corrosion product layer on the surface of P110 steel was investigated in simulated oilfield environment using mass-loss experiment, potentiodynamic polarization curve, impedance spectroscopy, and SEM micrograph analysis. Samples of different times up to 240 h were tested during exposure. Corrosion product was primarily composed of Fe(Ca, Mg)(CO3)2, which was distinguished by two layers. With an increase in the exposure time, the charge transfer resistance and polarization resistance increased progressively, the uniform corrosion rate decreased, and the corrosion reaction was controlled by the diffusion process instead of the activation process. All phenomena were attributed to the formation of the protective corrosion product layer. More compact and lower porosity of the layer made it more difficult to transfer and diffuse through the corrosion product layer for the charges and ions. Similar results were obtained by electrochemical test and mass-loss experiment.

  19. Evaluation of Encapsulated Inhibitor for Autonomous Corrosion Protection

    Science.gov (United States)

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

    2015-01-01

    This work concerns the development of smart coating technologies based on microencapsulation for the autonomous control of corrosion. Microencapsulation allows the incorporation of corrosion inhibitors into coating which provides protection through corrosion-controlled release of these inhibitors.One critical aspect of a corrosion protective smart coating is the selection of corrosion inhibitor for encapsulation and comparison of the inhibitor function before and after encapsulation. For this purpose, a systematic approach is being used to evaluate free and encapsulated corrosion inhibitors by salt immersion. Visual, optical microscope, and Scanning Electron Microscope (with low-angle backscatter electron detector) are used to evaluate these inhibitors. It has been found that the combination of different characterization tools provide an effective method for evaluation of early stage localized corrosion and the effectiveness of corrosion inhibitors.

  20. Corrosion Protection of Metal Matrix Composites

    Science.gov (United States)

    1990-04-01

    2, 162 (1986). 8. B. R. W. Hinton, D. R. Arnott, and N. E. Ryan, Metals Forum, Z, 211,(1984) 9. Ullmann , Fritz, "Ullmann’s Encyclopedia of Industrial ... Chemistry ", (1985). 10. F. Keller, M. S . Hunter, and 0. L. Robinson, J. Electrochem Soc., IM0, 411 0 (1953) 11. F. Mansfeld, S . Lin, S . Kim, and H...OIC FILE COPY "/9° * AD-A222 951 CORROSION PROTECTION OF METAL MATRIX COMPOSITES 0 FINAL REPORT F. MANSFELD, S . LIN AND H. SHIN APRIL 1990 0 U. S

  1. Cathodic corrosion protection of steel pipes; Kathodischer Korrosionsschutz von Rohrleitungsstaehlen

    Energy Technology Data Exchange (ETDEWEB)

    Buechler, Markus [SGK Schweizerische Gesellschaft fuer Korrosionsschutz, Zuerich (Switzerland); Schoeneich, Hanns-Georg [Open Grid Europe, Essen (Germany)

    2011-07-01

    The cathodic corrosion protection has been proven excellently in the practical use for buried steel pipelines. This is evidenced statistically by a significantly less frequency of loss compared to non-cathodically protected pipelines. Based on thermodynamic considerations, the authors of the contribution under consideration describe the operation of the cathodic corrosion protection and regular adjustment of the electrochemical potential at the interface steel / soil in practical use. Subsequently, the corrosion scenarios are discussed that may occur when an incorrect setting of the potential results from an operation over several decades. This incorrect setting also can be caused by the failure of individual components of the corrosion protection.

  2. Protecting the ozone layer.

    Science.gov (United States)

    Munasinghe, M; King, K

    1992-06-01

    Stratospheric ozone layer depletion has been recognized as a problem by the Vienna Convention for the Protection of the Ozone Layer and the 1987 Montreal Protocol (MP). The ozone layer shields the earth from harmful ultraviolet radiation (UV-B), which is more pronounced at the poles and around the equator. Industrialized countries have contributed significantly to the problem by releasing chlorofluorocarbons (CFCs) and halons into the atmosphere. The effect of these chemicals, which were known for their inertness, nonflammability, and nontoxicity, was discovered in 1874. Action to deal with the effects of CFCs and halons was initiated in 1985 in a 49-nation UN meeting. 21 nations signed a protocol limiting ozone depleting substances (ODS): CFCs and halons. Schedules were set based on each country's use in 1986; the target phaseout was set for the year 2000. The MP restricts trade in ODSs and weights the impact of substances to reflect the extent of damage; i.e., halons are 10 times more damaging than CFCs. ODS requirements for developing countries were eased to accommodate scarce resources and the small fraction of ODS emissions. An Interim Multilateral Fund under the Montreal Protocol (IMFMP) was established to provide loans to finance the costs to developing countries in meeting global environmental requirements. The IMFMP is administered by the World Bank, the UN Environmental Program, and the UN Development Program. Financing is available to eligible countries who use .3 kg of ODS/person/year. Rapid phaseout in developed countries has occurred due to strong support from industry and a lower than expected cost. Although there are clear advantages to rapid phaseout, there were no incentives included in the MP for rapid phaseout. Some of the difficulties occur because the schedules set minimum targets at the lowest possible cost. Also, costs cannot be minimized by a country-specific and ODS-specific process. The ways to improve implementation in scheduling and

  3. 用于燃气锅炉低碳钢耐冲蚀-腐蚀磨损的双层热喷涂层%Thermal Sprayed Dual-layer Coatings for Steel Protection against Corrosion-Erosion at Power Boilers

    Institute of Scientific and Technical Information of China (English)

    王卜谦; 税正荣; 王海斗

    2001-01-01

    为防护发电厂锅炉的热交换器管道的腐蚀冲蚀磨损,研究开发了一种热喷涂双层涂层(高速火焰喷涂Cr3C2/TiC–25NiCr涂层+燃烧电弧喷涂Ni21Cr9Mo35Nb涂层).在锅炉管道上实际应用两年后,对这种双涂层进行冲蚀试验和金相分析,并对其性能进行讨论.结果发现,燃烧电弧喷涂Ni21Cr9Mo3.5Nb涂层在高硫及氯环境中是一种良好的防护涂层.%The heat exchanger tubes of power plant boilers suffer from corrosion-erosion by ash particles and corrosive gases attack at elevated temperatures. The tube wastage rate depends on the boiler design and operation, the characteristics of ash particles, environment conditions, and tube materials. Thermal sprayed dual-layer coatings (HVOF Cr3C2/TiC-25NiCr coating and combustion arc-sprayed Ni21Cr9Mo3.5Nb coating) were developed for the tube corrosion-erosion protection. The erosion test comparison and metallographic examination of the coated tube after two years service in boiler were presented and its performance was discussed. The combustion arc-sprayed Ni21Cr9Mo3.5Nb coating was found a good solution for relatively high sulfur and chlorine environment.

  4. Marine corrosion protective coatings of hexagonal boron nitride thin films on stainless steel.

    Science.gov (United States)

    Husain, Esam; Narayanan, Tharangattu N; Taha-Tijerina, Jose Jaime; Vinod, Soumya; Vajtai, Robert; Ajayan, Pulickel M

    2013-05-22

    Recently, two-dimensional, layered materials such as graphene and hexagonal boron nitride (h-BN) have been identified as interesting materials for a range of applications. Here, we demonstrate the corrosion prevention applications of h-BN in marine coatings. The performance of h-BN/polymer hybrid coatings, applied on stainless steel, were evaluated using electrochemical techniques in simulated seawater media [marine media]. h-BN/polymer coating shows an efficient corrosion protection with a low corrosion current density of 5.14 × 10(-8) A/cm(2) and corrosion rate of 1.19 × 10(-3) mm/year and it is attributed to the hydrofobic, inert and dielectric nature of boron nitride. The results indicated that the stainless steel with coatings exhibited improved corrosion resistance. Electrochemical impedance spectroscopy and potentiodynamic analysis were used to propose a mechanism for the increased corrosion resistance of h-BN coatings.

  5. Protection of bronze artefacts through polymeric coatings based on nanocarriers filled with corrosion inhibitors

    Science.gov (United States)

    de Luna, Martina Salzano; Buonocore, Giovanna; Di Carlo, Gabriella; Giuliani, Chiara; Ingo, Gabriel M.; Lavorgna, Marino

    2016-05-01

    Protective coatings based on polymers synthesized from renewable sources (chitosan or an amorphous vinyl alcohol based polymer) have been prepared for the protection of bronze artifacts from corrosion. Besides acting as an effective barrier against corrosive species present in the environment, the efficiency of the coatings has been improved by adding corrosion inhibitor compounds (benzotriazole or mercaptobenzothiazole) to the formulations. The liquid medium of the formulations has been carefully selected looking at maximizing the wettability on the bronze substrate and optimizing the solvent evaporation rate. The minimum amount of inhibitor compounds has been optimized by performing accelerated corrosion tests on coated bronze substrates. The inhibitors have been directly dissolved in the coating-forming solutions and/or introduced by means of nanocarriers, which allow to control the release kinetics. The free dissolved inhibitor molecules immediately provide a sufficient protection against corrosion. On the other hand, the inhibitor molecules contained in the nanocarriers serve as long-term reservoir, which can be activated by external corrosion-related stimuli in case of particularly severe conditions. Particular attention has been paid to other features which affect the coating performances. Specifically, the adhesion of the protective polymer layer to the bronze substrate has been assessed, as well as its permeability properties and transparency, the latter being a fundamental feature of protective coating for cultural heritages. Finally, the protective efficiency of the produced smart coatings has been assessed through accelerated corrosion tests.

  6. Thin Coatings of Polymeric Carbon and Carbon Nanotubes for Corrosion Protection

    Science.gov (United States)

    2009-02-01

    Carbon Nanotube Functionalization /Doping Polyvinylpyrrolidone (PVP) A) p-Doping C) Polymer Wrapping Model B) n-Doping Polyethyleneimine ( PEI ) SWCNT Paint...fluorine-containing) groups functions as the barrier layer Multilayer Smart Carbon Nanotube Coating Insoluble polymer layer top coating -PMMA Substrate...Thin Coatings of Polymeric Carbon and Carbon Nanotubes for Corrosion Protection Zafar Iqbal Department of Chemistry and Environmental Science New

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

    Science.gov (United States)

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

    2016-01-01

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

  8. Smart Coatings for Launch Site Corrosion Protection

    Science.gov (United States)

    Calle, Luz M.

    2014-01-01

    Smart, environmentally friendly paint system for early corrosion detection, mitigation, and healing that will enable supportability in KSC launch facilities and ground systems through their operational life cycles. KSC's Corrosion Technology Laboratory is developing a smart, self-healing coating that can detect and repair corrosion at an early stage. This coating is being developed using microcapsules specifically designed to deliver the contents of their core when corrosion starts.

  9. Multicomponent Oxide Systems for Corrosion Protection.

    Science.gov (United States)

    1980-11-15

    and Si(OEt) 4 are somewhat lpss corrosive to aluminum than is SiCI 4 alone, although some pitting occurs for slow hydrolysis after coating by solutions...humidity (x) 86 A𔃻 determinants of corrosion resistance. The magnesium-silicon- aluminum alloy AA 6061 is generally considered to have good corrosion ... 6061 ), the corrosion resistance exceeded that of the chromate coatings. The feasibilityof the basic approach taken here has been validated. It

  10. The Corrosion Protection of Metals by Ion Vapor Deposited Aluminum

    Science.gov (United States)

    Danford, M. D.

    1993-01-01

    A study of the corrosion protection of substrate metals by ion vapor deposited aluminum (IVD Al) coats has been carried out. Corrosion protection by both anodized and unanodized IVD Al coats has been investigated. Base metals included in the study were 2219-T87 Al, 7075-T6 Al, Titanium-6 Al-4 Vanadium (Ti-6Al-4V), 4130 steel, D6AC steel, and 4340 steel. Results reveal that the anodized IVD Al coats provide excellent corrosion protection, but good protection is also achieved by IVD Al coats that have not been anodized.

  11. Determination of Aquifer Protective Capacity and Corrosivity of Near Surface Materials in Yenagoa City, Nigeria

    Directory of Open Access Journals (Sweden)

    K.S. Okiongbo

    2011-08-01

    Full Text Available Geoelectrical sounding method was adopted in the evaluation of aquifer protective capacity and corrosivity of near surface materials in Yenagoa city, South South, Nigeria. A total of eleven Vertical Electrical Soundings (VES stations were occupied using the Schlumberger configuration. Five geoelectric layers were identified. Layers four and five are the likely aquiferous horizons with resistivities >280 Sm. The depth to the aquiferous horizon varied between 6.0-52.0 m, and has a rather irregular distribution and thickness. Corrosivity, isopach and longitudinal unit conductance (S maps were generated from the combination of first and second order geoelectric parameters. The results indicate that the INC and Opolo areas of the city are characterized by weak protective capacity (0.1-0.2 mhos while other locations investigated are underlain by materials which could be regarded as moderate (0.2-0.69 mhos to good (0.7-4.9 mhos protective capacity. Resistivity values within the second layer (11.0-53.0 Sm indicate that this layer is moderately aggressive and may likely form corrosion cells which may lead to significant corrosion failures of shallow subsurface piping facilities. The results of this study highlight a set of environmental factors (corrosivity and protective capacity that should not be ignored at the planning stages of residential and industrial estates.

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

    Science.gov (United States)

    Pan, Tongyan; Wang, Zhaoyang

    2013-11-01

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

  13. Multilayered Zn-Ni alloy coatings for better corrosion protection of mild steel

    Directory of Open Access Journals (Sweden)

    Sadananda Rashmi

    2017-06-01

    Full Text Available A simple aqueous electrolyte for the deposition of anti-corrosive Zn-Ni alloy coatings was optimized using conventional Hull cell method. The corrosion protection value of the electrodeposited coatings at a current density (c.d. range of 2.0–5.0 A dm−2 has been testified in 5 wt% NaCl solution, as representative corrosion medium. The electrochemical behavior of the coatings towards corrosion was related to its surface topography, elemental composition and phase structure using scanning electron microscopy (SEM, energy dispersive spectroscopy (EDS and X-ray diffraction (XRD analyses, respectively. Among the monolithic coatings developed at different c.d.’s, the coating obtained at 3.0 A dm−2 was found to be the best with least corrosion current (icorr value. Further, the corrosion protection efficacy of the monolayer coatings were improved to many folds through multilayer coating approach, by modulating the cyclic cathode current densities (CCCD’s. The composition modulated multilayer (CMM Zn-Ni alloy coating with 60 layers, developed from the combination of CCCD’s 3.0 and 5.0 A dm−2 was found to be the best with 3 fold enhancement in corrosion protection efficiency. The formation of multilayer coatings was confirmed using cross-sectional SEM, and the experimental results are discussed with tables and figures.

  14. Corrosion Protection for Space and Beyond

    Science.gov (United States)

    Calle, Luz Marina

    2007-01-01

    Florida is home to NASA's Launch Operations Center. Since its establishment in July 1962, the spaceport has served as the departure gate for every American manned mission and hundreds of advanced scientific spacecraft under the Launch Services Program. The center was renamed the John F. Kennedy Space Center in late 1963 to honor the president who put America on the path to the moon. Today, NASA is on the edge of a bold new chaIlenge: the ConsteIlation Program. ConsteIlation is a NASA program to create a new generation of spacecraft for human spaceflight, consisting primarily of the Ares I and Ares V launch vehicles, the Orion crew capsule, the Earth Departure stage and the Lunar access module. These spacecraft will be capable of performing a variety of missions, from Space Station resupply to lunar landings. The ambitious new endeavor caIls for NASA to return human explorers to the moon and then venture even farther, to Mars and beyond. As the nation's premier spaceport, Kennedy Space Center (KSC) will playa critical role in this new chapter in exploration, particularly in the conversion of the launch facilities to accommodate the new launch vehicles. To prepare for this endeavor, the launch site and facilities for the next generation of crew and cargo vehicles must be redesigned, assembled and tested. One critical factor that is being carefuIly considered during the renovation is protecting the new facilities and structures from corrosion and deterioration.

  15. Biobased polymers for corrosion protection of metals

    Science.gov (United States)

    Anticorrosive biobased polymers were developed in our lab. We isolated an exopolysaccharide produced by a microbe that, when coated on metal substrates, exhibited unique corrosion inhibition. Corrosion is a worldwide problem and impacts the economy, jeopardizes human health and safety, and impedes t...

  16. Microencapsulation Technologies for Corrosion Protective Coating Applications

    Science.gov (United States)

    Li, Wenyan; Buhrow, Jerry; Jolley, Scott; Calle, Luz; Pearman, Benjamin; Zhang, Xuejun

    2015-01-01

    Microencapsulation technologies for functional smart Coatings for autonomous corrosion control have been a research area of strong emphasis during the last decade. This work concerns the development of pH sensitive micro-containers (microparticles and microcapsules) for autonomous corrosion control. This paper presents an overview of the state-of-the-art in the field of microencapsulation for corrosion control applications, as well as the technical details of the pH sensitive microcontainer approach, such as selection criteria for corrosion indicators and corrosion inhibitors; the development and optimization of encapsulation methods; function evaluation before and after incorporation of the microcontainers into coatings; and further optimization to improve coating compatibility and performance.

  17. Corrosion and protection in reinforced concrete: pulse cathodic protection: an improved cost-effective alternative

    NARCIS (Netherlands)

    Koleva, D.A.

    2007-01-01

    Corrosion and protection in reinforced concrete. Pulse cathodic protection: an improved cost-effective alternative. The aim of the research project was to study the possibilities for establishing a new or improved electrochemical method for corrosion prevention/protection for reinforced concrete. Th

  18. Influence of the layer architecture of DLC coatings on their wear and corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Bobzin, Kirsten; Bagcivan, Nazlim; Theiss, Sebastian; Weiss, Raphael [RWTH Aachen (Germany). Inst. fuer Oberflaechentechnik; Depner, Udo; Trossmann, Torsten; Ellermeier, Joerg; Oechsner, Matthias [Technische Univ. Darmstadt (Germany). Inst. fuer Werkstoffkunde

    2012-06-15

    In this work, the influence of diamond-like carbon top layers deposited on two different types of layer architecture on wear and corrosion resistance is investigated. Physical vapour deposition coatings with a-C:H top layer of various thicknesses were deposited on plasma nitrided 42CrMo4 by reactive magnetron sputter ion plating. Beneath the top layer, an architecture with and without a-C interlayers was deposited. Investigations using potentiodynamic polarisation testing in artificial seawater as well as an impact tribometer show that it is possible to protect low-alloy heat treatable steel from both corrosion and wear by using pretreatment and an appropriate diamond-like carbon coating. Thicker a-C:H top layers as well as the addition of a-C interlayers resulted in an overall improvement in the coating behaviour. (orig.)

  19. Corrosion-protective coatings from electrically conducting polymers

    Science.gov (United States)

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

    1991-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    SUN Huanhuan; WANG Hui; MENG Fanling

    2011-01-01

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

  1. Electrodeposited Reduced Graphene Oxide Films on Stainless Steel, Copper, and Aluminum for Corrosion Protection Enhancement

    Directory of Open Access Journals (Sweden)

    Abdulkareem Mohammed Ali Al-Sammarraie

    2017-01-01

    Full Text Available The enhancement of corrosion protection of metals and alloys by coating with simple, low cost, and highly adhered layer is still a main goal of many workers. In this research graphite flakes converted into graphene oxide using modified Hammers method and then reduced graphene oxide was electrodeposited on stainless steel 316, copper, and aluminum for corrosion protection application in seawater at four temperatures, namely, 20, 30, 40, and 50°C. All corrosion measurements, kinetics, and thermodynamics parameters were established from Tafel plots using three-electrode potentiostat. The deposited films were examined by FTIR, Raman, XRD, SEM, and AFM techniques; they revealed high percentages of conversion to the few layers of graphene with confirmed defects.

  2. Corrosion behavior of boride layers evaluated by the EIS technique

    Energy Technology Data Exchange (ETDEWEB)

    Campos, I. [Instituto Politecnico Nacional. SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F. 07738 (Mexico)], E-mail: icampos@ipn.mx; Palomar-Pardave, M. [Universidad Autonoma Metropolitana-Azcapotzalco, Materials Department, Avenue San Pablo 180 Col. Reynosa Tamaulipas, Mexico D.F. 02200 (Mexico); Amador, A. [Tecnologico de Monterrey, Campus Ciudad de Mexico, Calle del Puente 222 Col. Ejidos de Huipulco, Mexico D.F. 14380 (Mexico); VillaVelazquez, C. [Instituto Politecnico Nacional. SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F. 07738 (Mexico); Hadad, J. [Tecnologico de Monterrey, Campus Ciudad de Mexico, Calle del Puente 222 Col. Ejidos de Huipulco, Mexico D.F. 14380 (Mexico)

    2007-09-30

    The corrosion behavior of boride layers at the AISI 304 steel surface is evaluated in the present study. Electrochemical impedance spectroscopy (EIS) technique was used for the evaluation of the polarization resistance at the steel surface, with the aid of AUTOLAB potentiostat. Samples were treated with boron paste thickness of 4 and 5 mm, in the range of temperatures 1123 {<=} T {<=} 1273 K and exposed time of 4 and 6 h. The electrochemical technique employed 10 mV AC with a frequency scan range from 8 kHz to 3 mHz in deaerated 0.1 M NaCl solution. Nyquist diagrams show that the highest values of corrosion resistance are present in the samples borided at the temperature of 1273 K, with treatment time of 4 h and 4 mm of boron paste thickness. The values of corrosion resistance on borided steels are compared with the porosity exhibited in the layers.

  3. Effect of Hydrogen Plasma on Model Corrosion Layers of Bronze

    Science.gov (United States)

    Fojtíková, P.; Sázavská, V.; Mika, F.; Krčma, F.

    2016-05-01

    Our work is about plasmachemical reduction of model corrosion layers. The model corrosion layers were produced on bronze samples with size of 10 × 10 × 5 mm3, containing Cu and Sn. Concentrated hydrochloric acid was used as a corrosive environment. The application of reduction process in low-pressure low-temperature hydrogen plasma followed. A quartz cylindrical reactor with two outer copper electrodes was used. Plasma discharge was generated in pure hydrogen by a RF generator. Each corroded sample was treated in different conditions (supplied power and a continual or pulsed regime with a variable duty cycle mode). Process monitoring was ensured by optical emission spectroscopy. After treatment, samples were analyzed by SEM and EDX.

  4. Using Protection Layers for a 2-Photon Water Splitting Device

    DEFF Research Database (Denmark)

    Seger, Brian; Mei, Bastian Timo; Frydendal, Rasmus;

    2015-01-01

    conditions.(2) I will follow this up by discussing how protection layers bypass the corrosion issue by creating a buffer layer.(3) Finally I will show how we integrated a photocatalyst/protection layer/(co-catalyst) scheme to produce highly efficient H2 evolution photocathodes and O2 evolution photoanodes.(3....... Vesborg, O. Hansen and I. Chorkendorff, Journal of the American Chemical Society, 135, 1057 (2013). 4. B. Mei, A. A. Permyakova, R. Frydendal, D. Bae, T. Pedersen, P. Malacrida, O. Hansen, I. E. L. Stephens, P. C. K. Vesborg, B. Seger and I. Chorkendorff, The Journal of Physical Chemistry Letters, 5, 3456...

  5. Effect of the layer of anodized 7075-T6 aluminium corrosion properties

    Science.gov (United States)

    Montoya Z, R. D.; L, E. Vera; Pineda T, Y.; Cedeño, M. L.

    2017-01-01

    Aluminium alloys are widely used in various sectors of industry. The 7075-T6 alloy corresponding to an Al-Zn T6, is mostly used as structural component in the aviation industry, due to the good relationship between weight and mechanical properties. However, the negative point of this alloys is the resistance to corrosion, which is why they need to be coated with an anodic film. Different surface treatments, such as anodizing, are used to improve corrosion resistance. Anodizing is an electrolytic process by which a protective layer on aluminium known as “alumina” is formed, this is formed by the passage of an electric current in an acidic electrolyte. This investigation presents a study of the effect of the thickness of layers of alumina deposited by anodized method, in the corrosion resistance of 7075-T6 aluminium. This study was performed by using in a solution of tartaric acid - sulfuric acid and an inorganic salt. To evaluate the influence alumina layer thickness on the corrosion properties some tests were carried out by using the electrochemical spectroscopy impedances (EIS) technique and Tafel polarization curves. It was found that the grown of the thickness of film favourably influences in the corrosion resistance.

  6. Enhanced High Temperature Corrosion Resistance in Advanced Fossil Energy Systems by Nano-Passive Layer Formation

    Energy Technology Data Exchange (ETDEWEB)

    Arnold R. Marder

    2007-06-14

    secondary layer of a corrosion protection in these regions. In a separate set of experiments, in-situ oxidation performed in x-ray photoelectron spectroscopy (XPS) equipment showed that the formation of aluminum oxide in a pure oxygen environment at 500 C was slowed by the addition of chromium.

  7. Corrosion detection in multi-layered rotocraft structures

    Energy Technology Data Exchange (ETDEWEB)

    ROACH,DENNIS P.; WALKINGTON,PHILLIP D.; HOHMAN,ED; MARSHALL,GREG

    2000-04-25

    Rotorcraft structures do not readily lend themselves to quantifiable inspection methods due to airframe construction techniques. Periodic visual inspections are a common practice for detecting corrosion. Unfortunately, when the telltale signs of corrosion appear visually, extensive repair or refurbishment is required. There is a need to nondestructively evaluate airframe structures in order to recognize and quantify corrosion before visual indications are present. Nondestructive evaluations of rotorcraft airframes face inherent problems different from those of the fixed wing industry. Most rotorcraft lap joints are very narrow, contain raised fastener heads, may possess distortion, and consist of thinner gage materials ({approximately}0.012--0.125 inches). In addition the structures involve stack-ups of two and three layers of thin gage skins that are separated by sealant of varying thickness. Industry lacks the necessary data techniques, and experience to adequately perform routine corrosion inspection of rotorcraft. In order to address these problems, a program is currently underway to validate the use of eddy current inspection on specific rotorcraft lap joints. Probability of detection (POD) specimens have been produced that simulate two lap joint configurations on a model TH-57/206 helicopter. The FAA's Airworthiness Assurance Center (AANC) at Sandia Labs and Bell Helicopter have applied single and dual frequency eddy current (EC) techniques to these test specimens. The test results showed enough promise to justify beta site testing of the eddy current methods evolved in this study. The technique allows users to distinguish between corrosion signals and those caused by varying gaps between the assembly of skins. Specific structural joints were defined as prime corrosion areas and a series of corrosion specimens were produced with 5--20% corrosion distributed among the layers of each joint. Complete helicopter test beds were used to validate the laboratory

  8. Chemical conversion coating for protecting magnesium alloys from corrosion

    Science.gov (United States)

    Bhargava, Gaurang; Allen, Fred M.; Skandan, Ganesh; Hornish, Peter; Jain, Mohit

    2016-01-05

    A chromate-free, self-healing conversion coating solution for magnesium alloy substrates, composed of 10-20 wt. % Mg(NO.sub.3).sub.2.6H.sub.2O, 1-5 wt. % Al(NO.sub.3).sub.3.9H.sub.2O, and less than 1 wt. % of [V.sub.10O.sub.28].sup.6- or VO.sub.3.sup.- dissolved in water. The corrosion resistance offered by the resulting coating is in several hundreds of hours in salt-spray testing. This prolonged corrosion protection is attributed to the creation of a unique structure and morphology of the conversion coating that serves as a barrier coating with self-healing properties. Hydroxoaluminates form the backbone of the barrier protection offered while the magnesium hydroxide domains facilitate the "slow release" of vanadium compounds as self-healing moieties to defect sites, thus providing active corrosion protection.

  9. The corrosion protection of aluminum by various anodizing treatments

    Science.gov (United States)

    Danford, Merlin D.

    1989-01-01

    Corrosion protection to 6061-T6 aluminum, afforded by both teflon-impregnated anodized coats (Polylube and Tufram) and hard-anodized coats (water sealed and dichromate sealed), was studied at both pH 5.5 and pH 9.5, with an exposure period of 28 days in 3.5 percent NaCl solution (25 C) for each specimen. In general, corrosion protection for all specimens was better at pH 9.5 than at pH 5.5. Protection by a Tufram coat proved superior to that afforded by Polylube at each pH, with corrosion protection by the hard-anodized, water-sealed coat at pH 9.5 providing the best protection. Electrochemical work in each case was corroborated by microscopic examination of the coats after exposure. Corrosion protection by Tufram at pH 9.5 was most comparable to that of the hard-anodized samples, although pitting and some cracking of the coat did occur.

  10. The corrosion protection of 2219-T87 aluminum by anodizing

    Science.gov (United States)

    Danford, M. D.

    1991-01-01

    Various types of anodizing coatings were studied for 2219-T87 aluminum. These include both type II and type III anodized coats which were water sealed and a newly developed and proprietary Magnaplate HCR (TM) coat. Results indicate that type II anodizing is not much superior to type II anodizing as far as corrosion protection for 2219-T87 aluminum is concerned. Magnaplate HCR (TM) coatings should provide superior corrosion protection over an extended period of time using a coating thickness of 51 microns (2.0 mils).

  11. 40 CFR 280.31 - Operation and maintenance of corrosion protection.

    Science.gov (United States)

    2010-07-01

    ... protection. All owners and operators of steel UST systems with corrosion protection must comply with the... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Operation and maintenance of corrosion... is used to store regulated substances: (a) All corrosion protection systems must be operated...

  12. Corrosion protection of condensing boilers with organic coatings

    Energy Technology Data Exchange (ETDEWEB)

    Faller, M.; Schicker, M.; Richner, P. [Swiss Federal Laboratories for Materials Testing and Research (EMPA), Duebendorf (Switzerland)

    2000-07-01

    An investigation was conducted into whether organic coatings may be used to provide protection from the corrosive condensate which occurs in condensing boilers. The suitability of various coating systems was investigated in laboratory tests. On the basis of these results, a heat curing phenolic resin was selected for field trials in boilers from various manufacturers. The boilers were operated for up to two years. The condition of the coating was investigated during operation and after completion of the trial period. It was found that the selected coating provides good corrosion protection in areas not exposed to very high temperatures, which is precisely where condensation is most severe and there is thus the greatest risk of corrosion. (orig.)

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

    Science.gov (United States)

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

    2015-12-01

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

  14. Realistic approach to corrosion protection of ballast water tanks

    NARCIS (Netherlands)

    Ferrari, G.M.; Buter, S.J.; Zhang, X.; Prent, C.S.W.

    2012-01-01

    Corrosion protection of ballast water tanks is very precarious because of the aggressiveness of the environment and the difficult accessibility of the areas. Numerous accidents have led to regulation by the International Maritime Organization (IMO). Practical circumstances in yards are often not ide

  15. 49 CFR 192.463 - External corrosion control: Cathodic protection.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false External corrosion control: Cathodic protection. 192.463 Section 192.463 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS...

  16. Corrosion protection of reinforcement by hydrophobic treatment of concrete

    NARCIS (Netherlands)

    Polder, R.B.; Vries, H. de

    1999-01-01

    Penetration of de-icing salts into concrete bridge decks may cause corrosion of reinforcement. Hydrophobic treatment of concrete was studied as additional protection. It was shown that hydrophobic treatment strongly reduces chloride ingress, during semi-permanent contact and in wetting/drying situat

  17. Corrosion protection of aluminum alloys in contact with other metals

    Science.gov (United States)

    Kuster, C. A.

    1969-01-01

    Study establishes the quality of chemical and galvanized protection afforded by anodized and aldozided coatings applied to test panels of various aluminum alloys. The test panels, placed in firm contact with panels of titanium alloys, were subjected to salt spray tests and visually examined for corrosion effect.

  18. FUNCTIONALLY GRADED ALUMINA/MULLITE COATINGS FOR PROTECTION OF SILICON CARBIDE CERAMIC COMPONENTS FROM CORROSION

    Energy Technology Data Exchange (ETDEWEB)

    Prof. Stratis V. Sotirchos

    2001-02-01

    The main objective of this research project was the formulation of processes that can be used to prepare compositionally graded alumina/mullite coatings for protection from corrosion of silicon carbide components (monolithic or composite) used or proposed to be used in coal utilization systems (e.g., combustion chamber liners, heat exchanger tubes, particulate removal filters, and turbine components) and other energy-related applications. Since alumina has excellent resistance to corrosion but coefficient than silicon carbide, the key idea of this project has been to develop graded coatings with composition varying smoothly along their thickness between an inner (base) layer of mullite in contact with the silicon carbide component and an outer layer of pure alumina, which would function as the actual protective coating of the component. (Mullite presents very good adhesion towards silicon carbide and has thermal expansion coefficient very close to that of the latter.)

  19. The effect of superhydrophobic wetting state on corrosion protection--the AKD example.

    Science.gov (United States)

    Ejenstam, Lina; Ovaskainen, Louise; Rodriguez-Meizoso, Irene; Wågberg, Lars; Pan, Jinshan; Swerin, Agne; Claesson, Per M

    2013-12-15

    Corrosion is of considerable concern whenever metal is used as construction material. In this study we address whether superhydrophobic coatings could be used as part of an environmentally friendly corrosion-protective system, and specific focus is put on how the wetting regime of a superhydrophobic coating affects corrosion inhibition. Superhydrophobic alkyl ketene dimer (AKD) wax coatings were produced, using different methods resulting in hierarchical structures, where the coatings exhibit the same surface chemistry but different wetting regimes. Contact angle measurements, ESEM, confocal Raman microscopy, open circuit potential and electrochemical impedance spectroscopy were used to evaluate the surfaces. Remarkably high impedance values of 10(10)Ω cm(2) (at 10(-2) Hz) were reached for the sample showing superhydrophobic lotus-like wetting. Simultaneous open circuit potential measurements suggest that the circuit is broken, most likely due to the formation of a thin air layer at the coating-water interface that inhibits ion transport from the electrolyte to the metal substrate. The remaining samples, showing superhydrophobic wetting in the rose state and hydrophobic Wenzel-like wetting, showed less promising corrosion-protective properties. Due to the absence of air films on these surfaces the coatings were penetrated by the electrolyte, which allowed the corrosion reaction to proceed. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Enhancement of active corrosion protection via combination of inhibitor-loaded nanocontainers.

    Science.gov (United States)

    Tedim, J; Poznyak, S K; Kuznetsova, A; Raps, D; Hack, T; Zheludkevich, M L; Ferreira, M G S

    2010-05-01

    The present work reports the synthesis of layered double hydroxides (LDHs) nanocontainers loaded with different corrosion inhibitors (vanadate, phosphate, and 2-mercaptobenzothiazolate) and the characterization of the resulting pigments by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The anticorrosion activity of these nanocontainers with respect to aluminum alloy AA2024 was investigated by electrochemical impedance spectroscopy (EIS). The bare metallic substrates were immersed in dispersions of nanocontainers in sodium chloride solution and tested to understand the inhibition mechanisms and efficiency. The nanocontainers were also incorporated into commercial coatings used for aeronautical applications to study the active corrosion protection properties in systems of industrial relevance. The results show that an enhancement of the active protection effect can be reached when nanocontainers loaded with different inhibitors are combined in the same protective coating system.

  1. Intercalation and Stability of Layered Semiconductive Material in Corrosive Environment

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The intercalation of 4-methyl pyridine (4-picoline) into layered semiconductive material (MnPS3) and the stability of the resulting materials in corrosive environments (water, HCI and open atmosphere) were investigated.Powder X-ray diffraction (XRD) indicated that the presence of water and hydrochloric acid greatly influenced the existing form of intercalation and its orientation in the interlayer of the host. Atmospheric environment (open air) affected the guest orientation in the interlayer of the host material. Phase transformation occurred and the material was stable. The intercalated compounds could be indexed in the trigonal unit cell. The XRD patterns exhibited sharp hkl reflections of the intercalated compounds, which formed in water and HCI,confirming that the materials were well crystalline and stable in corrosive environments.

  2. Mullite coatings for corrosion protection of silicon carbide

    Energy Technology Data Exchange (ETDEWEB)

    Mulpuri, R.; Sarin, V.K. [Boston Univ., MA (United States)

    1995-08-01

    SiC based ceramics have been identified as the leading candidate materials for elevated temperature applications in harsh oxidation/corrosion environments. It has been established that a protective coating can be effectively used to avoid problems with excessive oxidation and hot corrosion. However, to date, no coating configuration has been developed that can satisfy the stringent requirements imposed by such applications. Chemical Vapor Deposited (CVD) mullite coatings due to their desirable properties of toughness, corrosion resistance, and a good coefficient of thermal expansion match with SiC are being investigated as a potential candidate. Since mullite has never been successfully grown via CVD, the thermodynamics and kinetics of its formation were initially established and used as a guideline in determining the initial process conditions. Process optimization was carried out using an iterative process of theoretical analysis and experimental work coupled with characterization and testing. The results of theoretical analysis and the CVD formation characteristics of mullite are presented.

  3. Status of corrosions protection primers for the automotive industry

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann-Loeser, P. [Adam Opel AG, Ruesselsheim (Germany); Schnell, A. [DaimlerChrysler, Werk Sindelfingen (Germany); Stellnberger, K.H.; Androsch, F.M. [voestalpine Stahl, Linz (Austria); Reier, T. [SZMF, Salzgitter (Germany); Lewandowski, J. [ThyssenKrupp Stahl, Duisburg (Germany); Filthaut, C. [DOC Dortmunder OberflaechenCentrum, Dortmund (Germany); Besseyrias, A. [Arcelor / R and D LEDEPP, Florange (France); Dane, C. [Corus, Ijmuiden (Netherlands); Steinbeck, G. [Steel Institute VDEh, Duesseldorf (Germany)

    2005-07-01

    In Europe, 2.5 - 4 {mu}m Zn-pigmented corrosion protection primers (CPP) are being used by the automotive industry. A short introduction describing the development steps leading up to the state of the art will be given and also the reasons for using it in practice. For some applications it became necessary to try to achieve a significantly higher level of corrosion resistance than this ''first generation'' type coating can offer. It was also important to lower the curing temperature of the paint considerably in order to be able to supply bake-hardening grade steels. This type of corrosion protection primer is now called the ''second generation''. The Opel-production of the Astra-family started using 2{sup nd} generation CPP (4-6 {mu}m) on chromate-free pre-treatment and EG for hood and crash box in 2004. The newest developments show a high potential to lower the coating thickness even further and thus make cost savings possible. The development process is still ongoing and for effective progress, a good mutual basis for laboratory evaluation of properties is of valuable support. In a Steel Institute VDEh working group (Arcelor, Corus, Salzgitter, ThyssenKrupp, voestalpine), test procedures are being generated in order to be able to correctly assess properties such as corrosion resistance, adhesion, peeling-off behavior, etc. An overview of the procedures will be given together with correlations between laboratory results and reality. To round up the paper, corrosion protection primers have a number of potentials which can be utilized by the automotive industry to justify the additional cost. Examples highlighted with results giving evidence of these potentials will be shown. (orig.)

  4. Enhanced corrosion protective PANI-PAA/PEI multilayer composite coatings for 316SS by spin coating technique

    Energy Technology Data Exchange (ETDEWEB)

    Syed, Junaid Ali; Lu, Hongbin; Tang, Shaochun; Meng, Xiangkang, E-mail: mengxk@nju.edu.cn

    2015-01-15

    Highlights: • PANI-PAA/PEI multilayers with controllable thickness were fabricated by spin assembly. • PAA matrix results in the homogeneous dispersion of PANI in the composite coatings. • Spin coating combined with heating assures the linear increase in thickness with n. • The corrosion protection property of PANI-PAA/PEI coatings were optimized at n = 20. • Enhanced protection owing to multilayer structure that lengthens the diffusion pathway of ions. - Abstract: In the present study, polyaniline-polyacrylic acid/polyethyleneimine (PANI-PAA/PEI) composite coatings with a multilayer structure for corrosion protection of 316 stainless steels (316SS) were prepared by an alternate deposition. Spin coating combined with heating assists removal of residual water that result in a linear increase in thickness with layer number (n). The combination of PANI-PAA composite with PEI and their multilayer structure provides a synergistic enhancement of corrosion resistance properties as determined by electrochemical measurements in 3.5% NaCl solution. Importantly, the PANI-PAA/PEI coating with an optimized layer number of n = 20 shows improved corrosion protection. The superior performance was attributed to the formation of an interfacial oxide layer as well as the multilayer structure that extend the diffusion pathway of corrosive ions.

  5. Characterization of Corrosion Product Layers from CO2 Corrosion of 13Cr Stainless Steel in Simulated Oilfield Solution

    Science.gov (United States)

    Yin, Z. F.; Wang, X. Z.; Liu, L.; Wu, J. Q.; Zhang, Y. Q.

    2011-10-01

    The influence of temperature and flow rate on the characterization and mechanisms of corrosion product layers from CO2 corrosion of 13Cr stainless steel was carried out in simulated oilfield solution. Cyclic potentiodynamic polarization method as well as weight loss tests in autoclave were utilized to investigate pitting corrosion behavior at various temperatures. Weight loss tests were performed at 100 and 160 °C under dynamic and static flow conditions. At the same time, the significant pitting parameters such as E corr, E pit, E pp, ∆ E, and I pass in cyclic polarization curves at various temperatures were analyzed and compared for revealing the pitting behavior of 13Cr stainless steel. The surface measurement techniques such as SEM, XRD, and XPS were used to detect the corrosion product layers. The results showed that both temperature and flow rate had significant effects on characterization of corrosion product layers or passive films formed on 13Cr stainless steel in CO2 corrosion system. At high temperature, lots of pits were formed at the localized corrosion areas of metal surfaces. Corrosion rates under the condition of 5 m/s were higher than those under the static condition regardless of the test temperatures.

  6. Enhanced corrosion resistance of magnesium alloy by a silane-based solution treatment after an in-situ formation of the Mg(OH)2 layer

    Science.gov (United States)

    Gong, Fubao; Shen, Jun; Gao, Runhua; Xie, Xiong; Luo, Xiong

    2016-03-01

    A novel organic-inorganic Mg(OH)2/silane surface layer has been developed for corrosion protection of AZ31 magnesium alloy. The results of electrochemical impedance spectroscopy (EIS), the immersion tests, Fourier-transform infrared spectroscopy (FTIR) and sellotape tests showed that the Mg(OH)2/silane-based composite surface layer possessed excellent corrosion resistance and very good adhesion due to the formation of Si-O-Mg bond between Mg(OH)2 layer and silane layer. Electrochemical impedance spectroscopy tests results indicated that for the long-term corrosion protection of AZ31 the increase of the curing temperature improved the impedance of the composited layer when the curing temperature was lower than 130 °C. However, the impedance of the composited layer deceased when the curing temperature was more than 130 °C due to the carbonization of the silane layer.

  7. Robust Slippery Coating with Superior Corrosion Resistance and Anti-Icing Performance for AZ31B Mg Alloy Protection.

    Science.gov (United States)

    Zhang, Jialei; Gu, Changdong; Tu, Jiangping

    2017-03-29

    Biomimetic slippery liquid-infused porous surfaces (SLIPSs) are developed as a potential alternative to superhydrophobic surfaces (SHSs) to resolve the issues of poor durability in corrosion protection and susceptibility to frosting. Herein, we fabricated a double-layered SLIPS coating on the AZ31 Mg alloy for corrosion protection and anti-icing application. The porous top layer was infused by lubricant, and the compact underlayer was utilized as a corrosion barrier. The water-repellent SLIPS coating exhibits a small sliding angle and durable corrosion resistance compared with the SHS coating. Moreover, the SLIPS coating delivers durable anti-icing performance for the Mg alloy substrate, which is obviously superior to the SHS coating. Multiple barriers in the SLIPS coating, including the infused water-repellent lubricant, the self-assembled monolayers coated porous top layer, and the compact layered double hydroxide-carbonate composite underlayer, are suggested as being responsible for the enhanced corrosion resistance and anti-icing performance. The robust double-layered SLIPS coating should be of great importance to expanding the potential applications of light metals and their alloys.

  8. Corrosion Protection of AM50 Magnesium Alloy by Nafion/DMSO Organic Coatings

    Institute of Scientific and Technical Information of China (English)

    SONG Renguo; ZHENG Xiaohua; BAI Shuju; BLAWERT Carsten; DIETZEL Wolfgang

    2008-01-01

    The effectiveness of the corrosion protection of Nafion/Dimethysulfoxid (DMSO) organic coatings for AM50 magnesium alloy prepared by simple immersion and heat treatment was investigated. Its corrosion resistance and morphologies of the Nafion/DMSO organic coatings were studied by electrochemical corrosion testing and optical microscopy. The results show that Nafion/DMSO organic coatings can improve the corrosion resistance of AM50 magnesium alloy effectively. Also, the corrosion resistance increases with the surface density of the organic coatings.

  9. Microstructures of corrosion layer of ACSR conductor in atmospheric corrosion and corrosion mechanism%钢芯铝绞导线大气腐蚀产物层的结构及腐蚀机理

    Institute of Scientific and Technical Information of China (English)

    张建堃; 陈国宏; 王家庆; 张涛; 王煦; 汤文明

    2011-01-01

    The dry/wet NaCl+NaHSO3 atmosphere-salt spraying experiment of the aluminum conductor steel reinforced (ACSR) conductor was carried out to study the phases and microstructures of corrosion products and the corrosion mechanism in simulated air corrosion condition. The results show that the ACSR conductor is mainly corroded by pitting corrosion. The corrosion layer mainly consists of hydroxides, sulfates and sulfate-chloride double salts and their hydrates of Zn and Al. At the initial corroding stage, the corrosion pits form on the Al strands and the galvanizing Zn layer, which are gradually replaced by the continuous corrosion layers as prolonging the spraying time. In the ACSR conductor, a primary cell is generated between the galvanizing Zn layer and the internal Al layer in the electrolyte. In the cell, as an anode, the galvanizing Zn layer is violently etched, contrarily, as a cathode, the internal Al layer is protected. In the ACSR conductor, the sequence of the corrosion rate from high to low is the galvanizing Zn layer, the external Al layer and the internal Al layer.%在模拟大气腐蚀环境中,采用干/湿NaHSO3+NaCl水溶液盐雾试验研究钢芯铝绞(ACSR)导线腐蚀产物的相组成及腐蚀层结构,讨论其腐蚀机理.结果表明:ACSR导线中单股铝线或镀锌钢芯线的腐蚀主要表现为点蚀,腐蚀产物组成复杂,主要为锌和铝的氢氧化物、硫酸盐与氯化物的复式盐;在腐蚀初期,内外层铝股线及钢芯线表面镀锌层开始形成点蚀坑,逐步形成连续的腐蚀层:由于镀锌层和内层铝股线之间构成原电池,因为牺牲阳极效应,镀锌层腐蚀速率最大;而内层铝股线受到保护,腐蚀速率最小,外层铝股线腐蚀速率居中.

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

    Science.gov (United States)

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

    2013-07-01

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

  11. Protection against Corrosion of Aluminum Alloy in Marine Environment by Lawsonia inermis

    Directory of Open Access Journals (Sweden)

    H. M. Hajar

    2016-01-01

    Full Text Available The corrosion performance of aluminum alloy 5083 (AA5083 was investigated in the splash zone area simulated in salt spray cabinet at ambient temperature. Three paint formulations were prepared in accordance with different percentages of henna extract. FTIR method was used to determine the constituent of henna while weight loss and electrochemical method were applied to investigate the inhibition behaviour. The findings show that corrosion rate of aluminum alloy decreased with the increases of henna extract in the coating formulation. The rise of charge transfer resistance (Rct value has contributed to the greater protection of the coated aluminum. The decrease in double layer capacitance value (Cdl is another indicator that a better protective barrier has been formed in the presence of henna in the coating matrix.

  12. The corrosion protection of AA2024-T3 aluminium alloy by leaching of lithium-containing salts from organic coatings.

    Science.gov (United States)

    Visser, Peter; Liu, Yanwen; Zhou, Xiaorong; Hashimoto, Teruo; Thompson, George E; Lyon, Stuart B; van der Ven, Leendert G J; Mol, Arjan J M C; Terryn, Herman A

    2015-01-01

    Lithium carbonate and lithium oxalate were incorporated as leachable corrosion inhibitors in model organic coatings for the protection of AA2024-T3. The coated samples were artificially damaged with a scribe. It was found that the lithium-salts are able to leach from the organic coating and form a protective layer in the scribe on AA2024-T3 under neutral salt spray conditions. The present paper shows the first observation and analysis of these corrosion protective layers, generated from lithium-salt loaded organic coatings. The scribed areas were examined by scanning and transmission electron microscopy before and after neutral salt spray exposure (ASTM-B117). The protective layers typically consist of three different layered regions, including a relatively dense layer near the alloy substrate, a porous middle layer and a flake-shaped outer layer, with lithium uniformly distributed throughout all three layers. Scanning electron microscopy and white light interferometry surface roughness measurements demonstrate that the formation of the layer occurs rapidly and, therefore provides an effective inhibition mechanism. Based on the observation of this work, a mechanism is proposed for the formation of these protective layers.

  13. Improving Corrosion Resistance of Q235 Steel by Ni-Cr Alloyed Layer

    Institute of Scientific and Technical Information of China (English)

    HUANG Jun; ZHANG Pingze; WU Hongyan; BI Qiang

    2012-01-01

    Ni-Cr alloyed layer was formed on surface of Q235 steel by double glow plasma surface metallurgy to improve the corrosion resistance of substrate.The composition and microstructure of alloyed layer was analyzed by SEM and XRD.Potentiodynamic polarization and electrochemical impedance spectroscopy was applied to evaluate the corrosion resistance of the alloyed layer.The results showed working pressure had a great effect on structure of Ni-Cr alloyed layer,and the dense and smooth alloyed layer was prepared at 50 Pa working pressure.Compared with substrate,Ni-Cr alloyed layer exhibited higher corrosion potential,lower corrosion current density and larger charge transfer resistance,which indicated that Ni-Cr alloyed layer significantly modified the corrosion resistance of Q235 steel.

  14. Protection of copper surface with phytic acid against corrosion in chloride solution.

    Science.gov (United States)

    Peca, Dunja; Pihlar, Boris; Ingrid, Milošev

    2014-01-01

    Phytic acid (inositol hexaphosphate) was tested as a corrosion inhibitor for copper in 3% sodium chloride. Phytic acid is a natural compound derived from plants, it is not toxic and can be considered as a green inhibitor. Electrochemical methods of linear polarization and potentiodynamic polarization were used to study the electrochemical behaviour and evaluate the inhibition effectiveness. To obtain the optimal corrosion protection the following experimental conditions were investigated: effect of surface pre-treatment (abrasion and three procedures of surface roughening), pre-formation of the layer of phytic acid, time of immersion and concentration of phytic acid. To evaluate the surface pre-treatment procedures the surface roughness and contact angle were measured. Optimal conditions for formation of phytic layer were selected resulting in the inhibition effectiveness of nearly 80%. Morphology and composition of the layer were further studied by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The layer of phytic acid with thickness in the nanometer range homogeneously covers the copper surface. The obtained results show that this natural compound can be used as a mildly effective corrosion inhibitor for copper in chloride solution.

  15. Corrosion and optimum corrosion protection potential offriction stir welded 5083-O Al alloy for leisure ship

    Institute of Scientific and Technical Information of China (English)

    Sung-Hyeon PARK; Jong-Shin KIM; Min-Su HAN; Seong-Jong KIM

    2009-01-01

    Electrochemical tests were undertaken to determine the optimum conditions in seawater for corrosion protection of friction stir-welded 5083-O Al alloy. Polarization trend observations show that the limiting potential that avoids the effects of hydrogen embrittlement is -1.6 V, corresponding to the crossover point between concentration polarization and activation polarization. However, the optimum protection potential is between -1.5 and -0.7 V since the current density at these values is low in the potentiostatic tests. When a galvanic cell is formed in the seawater, the welds exhibit electrochemically stable trends. Welded parts in galvanic tests with various area ratios are stable and have excellent anticorrosion characteristics.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-10-01

    Corrosion research, and the need to fully understand the effects that environmental conditions have on the performance of structural steels, is one area in which Moessbauer spectroscopy has become a required analytical technique. This is in part due to the need to identify and quantify the nanophase iron oxides that form on and protect certain structural steels, and that are nearly transparent to most other spectroscopic techniques. In conjunction with X-ray diffraction and micro-Raman analyses, the iron oxides that form the rusts on steels corroded in different marine and other environments can be completely identified and mapped within the rust coating. The spectroscopic analyses can be used to determine the nature of the environment in which structural steels have been, and these act as a monitor of the corrosion itself. Moessbauer spectroscopy is playing an important role in a new corrosion program in the United States and Japan in which steel bridges, old and new, are being evaluated for corrosion problems that may reduce their serviceable lifetimes. Moessbauer spectroscopy has been used to characterize the corrosion products that form the protective patina on weathering steel, as well those that form in adverse environments in which the oxide coating is not adherent or protective to the steel. Moessbauer spectroscopy has also become an important analytical technique for investigating the corrosion products that have formed on archaeological artifacts, and it is providing guidance to aid in the removal of the oxides necessary for their conservation.

  17. Corrosion Protection Systems and Fatigue Corrosion in Offshore Wind Structures: Current Status and Future Perspectives

    Directory of Open Access Journals (Sweden)

    Seth J. Price

    2017-02-01

    Full Text Available Concerns over reducing CO2 emissions associated with the burning of fossil fuels in combination with an increase in worldwide energy demands is leading to increased development of renewable energies such as wind. The installation of offshore wind power structures (OWS is one of the most promising approaches for the production of renewable energy. However, corrosion and fatigue damage in marine and offshore environments are major causes of primary steel strength degradation in OWS. Corrosion can reduce the thickness of structural components which may lead towards fatigue crack initiation and buckling. These failure mechanisms affect tower service life and may result in catastrophic structural failure. Additionally, environmental pollution stemming from corrosion’s by-products is possible. As a result, large financial investments are made yearly for both the prevention and recovery of these drawbacks. The corrosion rate of an OWS is dependent on different characteristics of attack which are influenced by access to oxygen and humidity. Structural degradation can occur due to chemical attack, abrasive action of waves, and microorganism attacks. Inspired by technological and scientific advances in recent years, the purpose of this paper is to discuss the current protective coating system technologies used to protect OWS as well as future perspectives.

  18. Corrosion and protection of NdFeB type magnets

    Science.gov (United States)

    Cavalloti, P.; Bozzini, B.; Cecchini, R.; Bava, G. F.; Davies, H. A.; Hoggarth, C.

    1992-02-01

    A general mechanism for the corrosion behaviour of NdFeB magnets is presented, related to the magnet heterogeneity with the presence of different phases. Cathodic control is outlined. An electrochemical method to assess the corrosion resistance of magnets, with and without coatings, is proposed; it is based on the study of the transient voltage at the magnet surface after a second cathodic current pulse in a suitable aggressive solution and its dependence on the amount of cathodic current circulating. Suitable pretreatments have been tried and interesting results obtained with passivation pretreatments, giving phosphorous Nd at grain boundaries. Coatings if sintered and plastic magnets have been tried using several methods. Good results are obtained with Zn-Co layers on sintered magnets and a sol-gel glass on powders for plastic magnets. Improved ACS (Autocatalytic Chemical Deposition) Ni=P coatings have been realized, with an alkaline brass flash plating to start ACD deposition.

  19. Development of Anticorrosive Polymer Nanocomposite Coating for Corrosion Protection in Marine Environment

    Science.gov (United States)

    Mardare, L.; Benea, L.

    2017-06-01

    The marine environment is considered to be a highly aggressive environment for metal materials. Steels are the most common materials being used for shipbuilding. Corrosion is a major cause of structural deterioration in marine and offshore structures. Corrosion of carbon steel in marine environment becomes serious due to the highly corrosive nature of seawater with high salinity and microorganism. To protect metallic materials particularly steel against corrosion occurrence various organic and inorganic coatings are used. The most used are the polymeric protective coatings. The nanostructured TiO2 polymer coating is able to offer higher protection to steel against corrosion, and performed relatively better than other polymer coatings.

  20. Corrosion protection performance of single and dual Plasma Electrolytic Oxidation (PEO) coating for aerospace applications

    Energy Technology Data Exchange (ETDEWEB)

    Madhan Kumar, A., E-mail: princemadhank@gmail.com; Kwon, Sun Hwan; Jung, Hwa Chul; Shin, Kwang Seon

    2015-01-15

    Plasma Electrolytic Oxidation (PEO) coatings are known to be one of the most appropriate method for corrosion protection of magnesium (Mg) alloy. The improvement of PEO coatings and the optimization of their surface aspects are of major importance. In this current work, the influence of dual PEO coating on strip-cast AZ31 Mg alloy substrate has been evaluated with the aim of improving the surface and corrosion protection aspects. For this purpose, AZ31 Mg substrates are subjected to single and dual PEO processing in silicate and phosphate electrolyte under similar condition. Scanning electron microscopy (SEM) analysis confirmed that the number of pores in PEO coating processed in silicate electrolyte is higher than others. X-ray diffraction analysis of PEO coatings showed that the surface coating is mainly comprised of Mg{sub 2}SiO{sub 4}, Mg{sub 3}(PO{sub 4}){sub 2} and MgO with different quantity based on PEO processing. Compared with the AZ31 Mg, the corrosion potential (E{sub corr}) of both type PEO coatings was positively shifted about 250–400 mV and the corrosion current density (i{sub corr}) was lowered by 3-4 orders of magnitude as result of adequate corrosion protection to the Mg alloy in 3.5% NaCl solution. All of the observation obviously showed that the dual PEO coating provides better corrosion protection performance than their respective single due to its synergistic beneficial effect. - Highlights: • Influence of dual PEO coating on AZ31 Mg alloy substrate was evaluated. • XRD confirmed formation of thin MgO inner, Mg{sub 3}(PO{sub 4}){sub 2} and Mg{sub 2}SiO{sub 4} outer layer. • SEM results showed uniform coating with no cracks and relatively less micro pores. • Micro hardness of dual PEO coatings is higher than single PEO coatings. • Dual coating provides superior corrosion performance due to its synergistic effect.

  1. Development of nanostructured coatings for protecting the surface of aluminum alloys against corrosion and ice accretion

    Science.gov (United States)

    Farhadi, Shahram

    Ice and wet snow accretion on outdoor structures is a severe challenge for cold climate countries. A variety of de-icing and anti-icing techniques have been developed so far to counter this problem. Passive approaches such as anti-icing or icephobic coatings that inhibit or retard ice accumulation on the surfaces are gaining in popularity. Metal corrosion should also be taken into account as metallic substrates are subject to corrosion problems when placed in humid or aggressive environments. Development of any ice-releasing coatings on aluminum structures, as they must be durable enough, is therefore closely related to anti-corrosive protection of that metal. Accordingly, series of experiments have been carried out to combine reduced ice adhesion and improved corrosion resistance on flat AA2024 substrates via thin films of single and double layer alkyl-terminated SAMs coatings. More precisely, alkyl-terminated aluminum substrates were prepared by depositing layer(s) of 18C-SAMs on BTSE-grafted AA2024 or mirror-polished AA2024 surfaces. This alloy is among the most widely used aluminum alloys in transportation systems (including aircraft), the military, etc. The stability of the coatings in an aggressive environment, their overall ice-repellent performance as well as their corrosion resistance was systematically studied. The stability of one-layer and two-layer coatings in different media was tested by means of CA measurements, demonstrating gradual loss of the hydrophobic property after ~1100-h-long immersion in water, associated by decrease in water CA. Surface corrosion was observed in all cases, except that the double-layer coating system provided improved anti-corrosive protection. All single layer coatings showed initial shear stress of ice detachment values of ~1.68 to 2 times lower than as-received aluminum surfaces and about ~1.22 to 1.5 times lower than those observed on mirror-polished surfaces. These values gradually increased after as many as 5 to 9

  2. The role of surface preparation in corrosion protection of copper with nanometer-thick ALD alumina coatings

    Science.gov (United States)

    Mirhashemihaghighi, Shadi; Światowska, Jolanta; Maurice, Vincent; Seyeux, Antoine; Klein, Lorena H.; Salmi, Emma; Ritala, Mikko; Marcus, Philippe

    2016-11-01

    Surface smoothening by substrate annealing was studied as a pre-treatment for improving the corrosion protection provided to copper by 10, 20 and 50 nm thick alumina coatings deposited by atomic layer deposition. The interplay between substrate surface state and deposited film thickness for controlling the corrosion protection provided by ultrathin barrier films is demonstrated. Pre-annealing at 750 °C heals out the dispersed surface heterogeneities left by electropolishing and reduces the surface roughness to less than 2 nm independently of the deposited film thickness. For 10 nm coatings, substrate surface smoothening promotes the corrosion resistance. However, for 20 and 50 nm coatings, it is detrimental to the corrosion protection due to local detachment of the deposited films. The weaker adherence of the thicker coatings is assigned to the stresses accumulated in the films with increasing deposited thickness. Healing out the local heterogeneities on the substrate surface diminishes the interfacial strength that is bearing the stresses of the deposited films, thereby increasing adhesion failure for the thicker films. Pitting corrosion occurs at the local sites of adhesion failure. Intergranular corrosion occurs at the initially well coated substrate grain boundaries because of the growth of a more defective and permeable coating at grain boundaries.

  3. The role of surface preparation in corrosion protection of copper with nanometer-thick ALD alumina coatings

    Energy Technology Data Exchange (ETDEWEB)

    Mirhashemihaghighi, Shadi; Światowska, Jolanta [PSL Research University, CNRS – Chimie ParisTech, Institut de Recherche de Chimie Paris (IRCP), 11 rue Pierre et Marie Curie, 75005 Paris (France); Maurice, Vincent, E-mail: vincent.maurice@chimie-paristech.fr [PSL Research University, CNRS – Chimie ParisTech, Institut de Recherche de Chimie Paris (IRCP), 11 rue Pierre et Marie Curie, 75005 Paris (France); Seyeux, Antoine; Klein, Lorena H. [PSL Research University, CNRS – Chimie ParisTech, Institut de Recherche de Chimie Paris (IRCP), 11 rue Pierre et Marie Curie, 75005 Paris (France); Salmi, Emma; Ritala, Mikko [Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland); Marcus, Philippe [PSL Research University, CNRS – Chimie ParisTech, Institut de Recherche de Chimie Paris (IRCP), 11 rue Pierre et Marie Curie, 75005 Paris (France)

    2016-11-30

    Highlights: • 10–50 nm thick alumina coatings were grown on copper by atomic layer deposition. • Surface smoothening by substrate annealing was studied as pre-deposition treatment. • Corrosion protection is promoted by pre-treatment for 10 nm but not for thicker films. • Local adhesion failure is assigned to the stresses accumulated in the thicker films. • Surface smoothening decreases the interfacial strength bearing the film stresses. - Abstract: Surface smoothening by substrate annealing was studied as a pre-treatment for improving the corrosion protection provided to copper by 10, 20 and 50 nm thick alumina coatings deposited by atomic layer deposition. The interplay between substrate surface state and deposited film thickness for controlling the corrosion protection provided by ultrathin barrier films is demonstrated. Pre-annealing at 750 °C heals out the dispersed surface heterogeneities left by electropolishing and reduces the surface roughness to less than 2 nm independently of the deposited film thickness. For 10 nm coatings, substrate surface smoothening promotes the corrosion resistance. However, for 20 and 50 nm coatings, it is detrimental to the corrosion protection due to local detachment of the deposited films. The weaker adherence of the thicker coatings is assigned to the stresses accumulated in the films with increasing deposited thickness. Healing out the local heterogeneities on the substrate surface diminishes the interfacial strength that is bearing the stresses of the deposited films, thereby increasing adhesion failure for the thicker films. Pitting corrosion occurs at the local sites of adhesion failure. Intergranular corrosion occurs at the initially well coated substrate grain boundaries because of the growth of a more defective and permeable coating at grain boundaries.

  4. Electrochemical and pitting corrosion resistance of AISI 4145 steel subjected to massive laser shock peening treatment with different coverage layers

    Science.gov (United States)

    Lu, J. Z.; Han, B.; Cui, C. Y.; Li, C. J.; Luo, K. Y.

    2017-02-01

    The effects of massive laser shock peening (LSP) treatment with different coverage layers on residual stress, pitting morphologies in a standard corrosive solution and electrochemical corrosion resistance of AISI 4145 steel were investigated by pitting corrosion test, potentiodynamic polarisation test, and SEM observations. Results showed massive LSP treatment can effectively cause an obvious improvement of pitting corrosion resistance of AISI 4145 steel, and increased coverage layer can also gradually improve its corrosion resistance. Massive LSP treatment with multiple layers was shown to influence pitting corrosion behaviour in a standard corrosive solution.

  5. Concentration Boundary Layer Model of Mortar Corrosion by Sulfuric Acid

    Institute of Scientific and Technical Information of China (English)

    SONG Zhigang; ZHANG Xuesong; MIN Hongguang

    2011-01-01

    A long time immersion experiment of mortar specimens is carried out to investigate their degradation mechanism by sulfuric acid. Water-cement ratios of mortar are ranging from 0.5 to 0.7 and the pH value of sulfuric acid is 3.5 and 4.0 respectively. The pH meter is used to monitor the soak solution and the titration sulfuric acid with given concentration is added to maintain original pH value, through which the acid consumption of mortar is recorded. A theoretical reaction rate model is also proposed based on concentration boundary layer model. The results show that theoretical model fits the experimental results well and the corrosion mechanism can be modeled by a diffusion process accompanied with an irreversible chemical reaction when pH value of soak solution is no less than 3.5.

  6. Influence of Direct Current Electric Field on Corrosion Behavior of Tin Under a Thin Electrolyte Layer

    Science.gov (United States)

    Huang, H. L.; Bu, F. R.; Tian, J.; Liu, D.

    2017-08-01

    The influence of a direct current electric field (DCEF) on corrosion behavior of tin under a thin electrolyte layer was investigated based on an array electrode technology by polarization, electrochemical impedance spectroscopy and surface analysis. The experimental results indicate that the corrosion rate of tin near the positive plate of DCEF increases with increased electric field intensity, which could be attributed to the acceleration of the migration of ions, the removal of corrosion products under DCEF and the damage of tin surface oxide film. Furthermore, tin at different positions in a DCEF exhibits different corrosion behavior, which could be ascribed to the difference of the local corrosion environment caused by the DCEF.

  7. Assembly of polyaniline nanotubes by interfacial polymerization for corrosion protection.

    Science.gov (United States)

    Oueiny, C; Berlioz, S; Perrin, F X

    2016-02-01

    Polyaniline (PANI) was synthesized by the oxidation of aniline with ammonium peroxydisulfate as an oxidant in an immiscible organic/aqueous biphasic system and with decylphosphonic acid (DPA) or benzylphosphonic acid (BPA) in the aqueous phase. Nanofibers of aniline oligomers were produced using BPA in the aqueous phase while high quality polyaniline nanotubes were produced using DPA in the aqueous phase. PANI nanotubes have a outer diameter 160-240 nm, an inner diameter of 50-100 nm and a length of the order of several μm. The understanding of the formation of PANI nanotubes was examined by isolation of reaction intermediates and their ex situ characterization by atomic force microscopy. The roles of BPA and DPA on the morphology formation of the PANI nanostructures were discussed. A nanofibrillar template produced by aniline oligomers was found to guide the growth of PANI to nanotubular morphology. PANI nanotubes are thus not derived from DPA vesicles. Preliminary corrosion tests exhibit high corrosion protection efficiency of PANI nanotubes because of their high surface area and corrosion inhibitive properties of DPA dopant.

  8. Corrosion and wear resistant metallic layers produced by electrochemical methods

    DEFF Research Database (Denmark)

    Christoffersen, Lasse; Maahn, Ernst Emanuel

    1999-01-01

    Corrosion and wear-corrosion properties of novel nickel alloy coatings with promising production characteristics have been compared with conventional bulk materials and hard platings. Corrosion properties in neutral and acidic environments have been investigated with electrochemical methods....... Determination of polarisation resistance during 100 hours followed by stepwise anodic polarisation seems to be a promising technique to obtain steady state data on slowly corroding coatings with transient kinetics. A slurry test enables determination of simultaneous corrosion and abrasive wear. Comparison...

  9. Coatings for Oxidation and Hot Corrosion Protection of Disk Alloys

    Science.gov (United States)

    Nesbitt, Jim; Gabb, Tim; Draper, Sue; Miller, Bob; Locci, Ivan; Sudbrack, Chantal

    2017-01-01

    Increasing temperatures in aero gas turbines is resulting in oxidation and hot corrosion attack of turbine disks. Since disks are sensitive to low cycle fatigue (LCF), any environmental attack, and especially hot corrosion pitting, can potentially seriously degrade the life of the disk. Application of metallic coatings are one means of protecting disk alloys from this environmental attack. However, simply the presence of a metallic coating, even without environmental exposure, can degrade the LCF life of a disk alloy. Therefore, coatings must be designed which are not only resistant to oxidation and corrosion attack, but must not significantly degrade the LCF life of the alloy. Three different Ni-Cr coating compositions (29, 35.5, 45wt. Cr) were applied at two thicknesses by Plasma Enhanced Magnetron Sputtering (PEMS) to two similar Ni-based disk alloys. One coating also received a thin ZrO2 overcoat. The coated samples were also given a short oxidation exposure in a low PO2 environment to encourage chromia scale formation. Without further environmental exposure, the LCF life of the coated samples, evaluated at 760C, was less than that of uncoated samples. Hence, application of the coating alone degraded the LCF life of the disk alloy. Since shot peening is commonly employed to improve LCF life, the effect of shot peening the coated and uncoated surface was also evaluated. For all cases, shot peening improved the LCF life of the coated samples. Coated and uncoated samples were shot peened and given environmental exposures consisting of 500 hrs of oxidation followed by 50 hrs of hot corrosion, both at 760C). The high-Cr coating showed the best LCF life after the environmental exposures. Results of the LCF testing and post-test characterization of the various coatings will be presented and future research directions discussed.

  10. Model and numerical analysis of 3D corrosion layer of reinforced concrete structure

    Institute of Scientific and Technical Information of China (English)

    李永和; 葛修润

    2003-01-01

    Under the assumption that the corrosion at the end of steel bolt or steel bar is shaped like the contour line of ellipsoid, a mathematic model and formulas of calculating the thickness of corrosion layer at arbitrary point are presented in this paper. Then regarding the arbitrary points of 3D corrosion layer as patch element model of fictitious displacement discontinuity, we propose the basic solution of 3D problem of the patch element acting on discontinuous displacement. With three basic assumptions of the corrosion layer, we set up the 3D numerical discreted model, and derive the stress boundary equation for fictitious corrosion layer of 3D numerical analysis. We also make the numerical stimulating calculation of the shotcrete structure at some lane using 3D finite element method. The results show that this method is effective and reasonable.

  11. Generation reason and corrosion characteristic of cavity of tinplate alloy layer

    Institute of Scientific and Technical Information of China (English)

    黄久贵; 李宁; 周德瑞

    2004-01-01

    The surface morphology of alloy layer of tinplate was studied by means of scanning electron microscopy.By using the layer on layer debonding technology of glow discharge spectrum, the contents of C and O at the boundary of alloy layer and black plate were analyzed. And the corrosion characteristic of cavity of tinplate alloy layer was studied on-line and in-situ by means of electrochemical atomic force microscope. The corrosion depth of cavity of alloy layer in-situ after different corrosion time was measured. The results show that the cavity of alloy layer is a critical factor causing rapid decline of corrosion resistance of tinplate, and the formation of cavity of alloy layer is due to incorrect pretreatment of black plate before electrotinning. The cavity of alloy layer is the internal factor causing pitting corrosion of tinplate when the tinplate is applied to food packaging material. And the dynamic equation of pitting corrosion generated in the cavity of alloy layer conforms to logarithm law.

  12. Corrosion properties of S-phase layers formed on medical grade austenitic stainless steel.

    Science.gov (United States)

    Buhagiar, Joseph; Dong, Hanshan

    2012-02-01

    The corrosion properties of S-phase surface layers formed in AISI 316LVM (ASTM F138) and High-N (ASTM F1586) medical grade austenitic stainless steels by plasma surface alloying with nitrogen (at 430°C), carbon (at 500°C) and both carbon and nitrogen (at 430°C) has been investigated. The corrosion behaviour of the S-phase layers in Ringer's solutions was evaluated using potentiodynamic and immersion corrosion tests. The corrosion damage was evaluated using microscopy, hardness testing, inductive coupled plasma mass spectroscopy and X-ray diffraction. The experimental results have demonstrated that low-temperature nitriding, carburising and carbonitriding can improve the localised corrosion resistance of both industrial and medical grade austenitic stainless steels as long as the threshold sensitisation temperature is not reached. Carburising at 500°C has proved to be the best hardening treatment with the least effect on the corrosion resistance of the parent alloy.

  13. Structure and mechanical properties of the three-layer material based on a vanadium alloy and corrosion-resistant steel

    Science.gov (United States)

    Nikulin, S. A.; Rozhnov, A. B.; Nechaikina, T. A.; Rogachev, S. O.; Zavodchikov, S. Yu.; Khatkevich, V. M.

    2014-10-01

    The quality of three-layer pipes has been studied; they are manufactured by hot pressing of a three-layer assembly of tubular billets followed by forging and cold rolling. The operating core is made from a V-4Ti-4Cr alloy. The protective claddings are made from corrosion-resistant steels of two grades, 08Kh17T and 20Kh13. The results of investigation into the structure and microhardness of the junction zone of steel and the vanadium alloy, which includes a contact zone and a transition diffusion layer, are reported. The 08Kh17T steel is shown to be a preferred cladding material.

  14. Corrosion protection of secondary lithium electrodes in organic electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Besenhard, J.O.; Guertler, J.; Komenda, P.; Paxinos, A.

    1987-07-01

    Hydrocarbons show considerable surface activity in organic electrolytes;they, at least partially, displace the polar organic solvent molecules from any solid/electrolyte interface. Saturated hydrocarbons are chemically stable even versus lithium or lithium-rich alloys, and thus they are able to delay the irreversible reduction of organic electrolytes by these highly active negatives, i.e., they delay corrosion and surface filming of the negatives. As surface filming of lithium strongly controls the growth of lithium dendrites during electroplating, a delay in the filming process significantly decreased dendrite growth. Prevention of dendrite growth, however, requires speedy protection of freshly created 'dynamic' surfaces and, hence, a high concentration (and solubility) of the hydrocarbon surfactant. On the other hand, for the protection of 'static' electrodes under open cell conditions, even relatively insoluble surfactants may suffice.

  15. Corrosion

    Science.gov (United States)

    Slabaugh, W. H.

    1974-01-01

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

  16. Corrosion

    Science.gov (United States)

    Slabaugh, W. H.

    1974-01-01

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

  17. Corrosion Protection of Al/Au/ZnO Anode for Hybrid Cell Application

    OpenAIRE

    2015-01-01

    Effective protection of power sources from corrosion is critical in the development of abiotic fuel cells, biofuel cells, hybrid cells and biobateries for implantable bioelectronics. Corrosion of these bioelectronic devices result in device inability to generate bioelectricity. In this paper Al/Au/ZnO was considered as a possible anodic substrate for the development of a hybrid cell. The protective abilities of corrosive resistant aluminum hydroxide and zinc phosphite composite films formed o...

  18. Evaluation of aquifer protective capacity of overburden unit and soil corrosivity in Makurdi, Benue state, Nigeria, using electrical resistivity method

    Indian Academy of Sciences (India)

    Daniel N Obiora; Adeolu E Ajala; Johnson C Ibuot

    2015-02-01

    This paper presents result of 30 vertical electrical soundings carried out in Makurdi, Benue state capital, north–central Nigeria to evaluate aquifer protective capacity and soil corrosivity of overburden units in the study area. This was done using the Schlumberger electrode array to obtain the data and was modelled using computer iteration (Winresist software). The field data gives a resolution with 3–4 geoelectric layers and the observed frequencies in curve types include: 30% of KQ, 16.67% of QH, 6.67% of AA and K, 3.33% of HA, Q and A, 10% of H, KH and HK. Using the longitudinal unit conductance (S), the protective capacities of the study area were classified as 36.67% weak, 10% poor, 40% moderate, and 13.33% as good. The corrosivity ratings of the study area show that 10% is strongly corrosive, 23% moderately corrosive, 37% slightly corrosive, and 30% noncorrosive The results reasonably provide information on areas where industries can be sited and iron pipes can be laid in order to safeguard the hydrological setting for resident’s safety in the study area. Regions with moderate/good protective capacity are good sites for locating boreholes.

  19. Electrophoretic deposition of hybrid coatings on aluminum alloy by combining 3-aminopropyltrimethoxysilan to silicon–zirconium sol solutions for corrosion protection

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Mei; Xue, Bing; Liu, Jianhua, E-mail: yumei@buaa.edu.cn; Li, Songmei; Zhang, You

    2015-09-01

    Electrophoretic deposition (EPD) silicon–zirconium organic–inorganic hybrid coatings were applied on LC4 aluminum alloy for corrosion protection. 3-Glycidoxypropyl-trimethoxysilane (GTMS) and Zirconium (IV) n-propoxide (TPOZ) were used as precursors. 3-Aminopropyl-trimethoxysilane (APS) was added to enhance the corrosion protective performance of the coatings. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) were employed to characterize morphology, microstructure and component. The results show that the addition of APS leads to the enhanced migration and deposition of positively charged colloidal particles on the surface of metal substrate, which results in the thickness increasing of coatings. However, loading an excessive amount of APS gives a heterogeneous coating surface. The corrosion protective performance of coatings were measured by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The results indicate that the addition of APS improves corrosion protective performance of coatings. The optimal addition content of APS is about 15%. The 15% APS coating is uniform and dense, as well as has good corrosion protective performance. The impedance value (1.58 × 10{sup 5} Ω·cm{sup 2}, at the lowest frequency) of 15% APS coating is half order of magnitude higher than that of coating without APS, and 15% APS coating always keeps the best corrosion protective performance with prolonged immersion time. This kind of coating is identified with “double-structure” properties based on the analysis of EIS and potentiodynamic polarization. Furthermore, the equivalent circuit results indicate that the intermediate oxide layer plays a main role in corrosion protection. - Highlights: • Electrophoretic deposition hybrid coatings are prepared on LC4 aluminum alloy. • 3-Aminopropyl-trimethoxysilane (APS) enhances the corrosion protective performance. • The

  20. Lipid Layer-based Corrosion Monitoring on Metal Substrates

    Science.gov (United States)

    2013-04-01

    nonconductive coatings (6) and detection of chemical agents (7), and also in their use as a corrosion inhibitor (8). The goal of this research is to expand...Distribution List 8 iv List of Figures Figure 1. (a) Uncoated Al 6061 plate prior to corrosion and (b) DPPC lipid coated Al 6061 plate prior to...and coated specimens after 42 days in salt fog chamber ........5 Figure 5. Plexiglass cover on the Al specimens for accelerated corrosion in the salt

  1. Electrochemical synthesis and characterisation of hybrid materials polypyrrole/dodecatungstophosphate as protective agents against steel corrosion

    Science.gov (United States)

    Bonastre Cano, Jose Antonio

    The losses caused by the effect of the corrosion are of the order of 2-3,5% of the GDP of the developed countries or developing only in direct costs, losses in structures or products. This figure doubles by the indirect costs, losses of productivity or demands for delays. Beside the possible losses of human lives, any intent leaded to the decrease of the corrosion in rusty metals is a commendable objective from the point of view of the protection of the environment. Building industry employing reinforced concrete is able to project some structural elements (pillars, wrought, beam, etc.) in principle free of corrosion, assuring during many years the useful life of the work in service. However, the reinforced concrete would be' a perfect solution if the indefinite permanency of the passive state of the steel could be guaranteed. Indeed, although the steel is protected against corrosion due to basic pH which provides the cement, the severe action of saline media or the effect of CO2 can diminish this protection conditions beginning the corrosion in steel elements. Type-p doped conducting polymers, as polypyrrole, are firm candidates to protect carbon steel providing galvanic protection by stabilising the passive layer of Fe oxides initially grown. Doping the polymeric matrix with polioxometalates, concretely phosphotungstate PW12O403-, is a very interesting hypothesis due to their oxidising effect, improving the anodic protection by the hybrid material electrosynthesised on carbon steel substrate. First in the present work, a new method was developed by cyclic voltammetry in LiClO4 + acetonitrile medium in order to diminish the unavoidable oxidation of carbon steel when the electrosyntesis of the hybrid material polypyrrole/PW12O403- is carrying out. The beginning potential of polypyrrole polymerisation is about 0.8 V (vs. Ag/AgCl), a positive potential where oxidation of Fe substrate is high, not allowing the electrodeposition of the hybrid material. On the other

  2. Recent Developments on Autonomous Corrosion Protection Through Encapsulation

    Science.gov (United States)

    Li, W.; Buhrow, J. W.; Calle, L. M.; Gillis, M.; Blanton, M.; Hanna, J.; Rawlins, J.

    2015-01-01

    This paper concerns recent progress in the development of a multifunctional smart coating, based on microencapsulation, for the autonomous detection and control of corrosion. Microencapsulation has been validated and optimized to incorporate desired corrosion control functionalities, such as early corrosion detection and inhibition, through corrosion-initiated release of corrosion indicators and inhibitors, as well as self-healing agent release triggered by mechanical damage. While proof-of-concept results have been previously reported, more recent research and development efforts have concentrated on improving coating compatibility and synthesis procedure scalability, with a targeted goal of obtaining easily dispersible pigment-grade type microencapsulated materials. The recent progress has resulted in the development of pH-sensitive microparticles as a corrosion-triggered delivery system for corrosion indicators and inhibitors. The synthesis and early corrosion indication results obtained with coating formulations that incorporate these microparticles are reported. The early corrosion indicating results were obtained with color changing and with fluorescent indicators.

  3. The corrosion protection of several aluminum alloys by chromic acid and sulfuric acid anodizing

    Science.gov (United States)

    Danford, M. D.

    1994-01-01

    The corrosion protection afforded 7075-T6, 7075-T3, 6061-T6, and 2024-T3 aluminum alloys by chromic acid and sulfuric acid anodizing was examined using electrochemical techniques. From these studies, it is concluded that sulfuric acid anodizing provides superior corrosion protection compared to chromic acid anodizing.

  4. Evaluating protection systems against marine corrosion of aeronautic alloy Alclad 2024-T3

    Directory of Open Access Journals (Sweden)

    William Aperador Chaparro

    2011-05-01

    Full Text Available  This paper shows how two coating systems were obtained as an alternative for protection against corrosion of al clad 2024-T3which is used in battery compartment manufacture for T-41 aircraft. Such systems consist of three types of organic resin: a first layer of P-115 polyester resin as the first coating on both systems, and a second layer of Hetron 197-3 polyester resin in the first system and vinyl-ester resin in the second one. Scanning electron microscopy (SEM was used for surface morphology analysis, showing the roughness produced by surface treatment. The coatings were electrochemically characterised by electro chemical impedance spectroscopy (EIS and Tafel polarization curves; it was found that both systems had good performance against corrosion in a marine environment and the chemical surface preparation system had a superior protective pattern for Alodine5700 + 197-3 Hetron, a 1.42x10-12mpycorrosion rate being obtained while substratum rate was 1.59x10-7 mpy. 

  5. Corrosion protection of Arctic offshore structures: Final report. [Effects of temperature and salinity on required cathodic protection current

    Energy Technology Data Exchange (ETDEWEB)

    Sackinger, W.M.; Rogers, J.C.; Feyk, C.; Theuveny, B.

    1985-10-01

    Results are presented for a research program on corrosion prevention for Arctic offshore structures which are in contact with sea ice for a significant portion of the year. The electrical method most adaptable for structure protection involves the injection of impressed current from several remote anodes buried just beneath the sea floor. The electrical resistivity of annual sea ice as a function of temperature and salinity is presented. Details of the interface layers formed between sea ice and steel in the presence of current injection are shown. A computer program was developed to enable the calculation of protective current density into the structure, in the presence of ice rubble and ridges around the structure. The program and the results of an example calculation are given for a caisson- retained island structure. 81 refs., 103 figs., 3 tabs.

  6. A combined corrosion protection system for reinforced concrete structures using a carbon fibre mesh

    Energy Technology Data Exchange (ETDEWEB)

    Bruns, M.; Raupach, M. [Institut fuer Bauforschung der RWTH Aachen, IBAC, Institute of Building Materials Research of the Technical University of Aachen, Schinkelstrasse 3 Aachen (Germany)

    2004-07-01

    Cathodic Protection (CP) has become a world-wide used method to protect reinforced concrete structures against reinforcement corrosion. Another method to stop or reduce reinforcement corrosion, at least in case of lower chloride contents is the reduction of the water content of the concrete by applying sealing coatings on the concrete surface. At the Institute of Building Materials Research of Aachen University (IBAC) actually a surface protection system is investigated based on the combination of both methods mentioned above. The idea is to protect the reinforcement within the first years after system installation by cathodic protection until the water content of the concrete has decreased to a level due to the surface coating where the corrosion rate of the reinforcement is uncritical and does not lead to any damage. The system investigated, consists of a carbon fibre net embedded in a special mortar layer as impressed current anode for cathodic protection, covered by a 'dense' cement based polymer modified surface coating. In order to investigate the system, it has been installed on a test area on the weathered upper deck of a parking garage in Aachen, Germany. To investigate the effectiveness regarding the reduction of the water content of the concrete the test area was equipped with so called Multiring-Electrodes (MRE) for depth depended measurement of the concrete resistivity. Reference electrodes for potential and depolarization measurements as well a device for automatic measurement of the protection current were installed to investigate the effectiveness of the impressed current cathodic protection. Additionally 3 re bars were embedded into the concrete of the test area using mortar containing 1, 2 or 3 M.-% chloride by weight of cement respectively, to investigate the influence of the chloride content. First results of the MRE-measurements showing already within the first months after system installation a distinct drying of the concrete cover

  7. Corrosion behavior of 907 steel under thin electrolyte layers of artificial seawater

    Institute of Scientific and Technical Information of China (English)

    王慧萍; 丁少春; 朱娟; 张昭; 张鉴清; 曹楚南

    2015-01-01

    The corrosion behavior of 907 steel under thin electrolyte layer (TEL) has been investigated by means of cathodic polarization curve measurement, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The results show that the cathodic diffusion current density presents the variation trend of initial increase and subsequent decrease with the decrease of TEL thickness, and the maximum deposits at 58 μm. The cotangent-hyperbolic impedance (O) is rationally first introduced to study the diffusion process of the reactants through the corrosion products layer with many permeable holes. The initial corrosion rate of 907 steel under different TEL thickness increases with the decrease of TEL thickness except that of 104 μm, whereas the corrosion rate after long time corrosion can be ranked as 104μm﹥402μm﹥198μm﹥301μm﹥bulk solution.

  8. Air-Impregnated Nanoporous Anodic Aluminum Oxide Layers for Enhancing the Corrosion Resistance of Aluminum.

    Science.gov (United States)

    Jeong, Chanyoung; Lee, Junghoon; Sheppard, Keith; Choi, Chang-Hwan

    2015-10-13

    Nanoporous anodic aluminum oxide layers were fabricated on aluminum substrates with systematically varied pore diameters (20-80 nm) and oxide thicknesses (150-500 nm) by controlling the anodizing voltage and time and subsequent pore-widening process conditions. The porous nanostructures were then coated with a thin (only a couple of nanometers thick) Teflon film to make the surface hydrophobic and trap air in the pores. The corrosion resistance of the aluminum substrate was evaluated by a potentiodynamic polarization measurement in 3.5 wt % NaCl solution (saltwater). Results showed that the hydrophobic nanoporous anodic aluminum oxide layer significantly enhanced the corrosion resistance of the aluminum substrate compared to a hydrophilic oxide layer of the same nanostructures, to bare (nonanodized) aluminum with only a natural oxide layer on top, and to the latter coated with a thin Teflon film. The hydrophobic nanoporous anodic aluminum oxide layer with the largest pore diameter and the thickest oxide layer (i.e., the maximized air fraction) resulted in the best corrosion resistance with a corrosion inhibition efficiency of up to 99% for up to 7 days. The results demonstrate that the air impregnating the hydrophobic nanopores can effectively inhibit the penetration of corrosive media into the pores, leading to a significant improvement in corrosion resistance.

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

    Science.gov (United States)

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

    2011-06-01

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

  10. Silicone coating systems to improve corrosion protection of steel; Silikonbeschichtungssysteme zur Verbesserung des Korrosionsschutzes von Stahl

    Energy Technology Data Exchange (ETDEWEB)

    Kucharczyk, P.; Fachinger, J.; Odoj, R. [Forschungszentrum Juelich GmbH (Germany); Boehnert, R. [Fachhochschule Koeln (Germany)

    2006-06-15

    Due to German policy an interim storage of radioactive waste during additional 30 years is needed. This requires a high standard of storage containers especially in terms of corrosion resistance. Silicon elastomers (polysiloxanes) have favourable physical and chemical properties and seem to be appropriate for either outer or inner coating of storage containers. In this paper corrosion protection of different silicon coating systems has been investigated. The addition-curing polysiloxane RT622 (Wacker Chemie) was used for experiments. This is a low-viscosity material that could be modified by corrosion protecting pigments like zinc powder and micaceous iron ore. The pigment coatings assured better corrosion protection than unmodified silicon covering. Furthermore, the zinc powder caused the most notable improvement of corrosion protection. The best coating system consisted of a zinc paint and a polysiloxane coating. (orig.)

  11. Recent Developments on Microencapsulation for Autonomous Corrosion Protection

    Science.gov (United States)

    Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Fitzpatrick, Lilliana; Jolley, Scott T.; Surma, Jan M.; Pearman, Benjamin P.; Zhang, Xuejun

    2014-01-01

    This work concerns recent progress in the development of a multifunctional smart coating based on microencapsulation for the autonomous control of corrosion. Microencapsulation allows the incorporation of desired corrosion control functionalities, such as early corrosion detection and inhibition through corrosion controlled release of corrosion indicators and inhibitors, as well as self-healing agent release when mechanical damage occurs.While proof-of-concept results have been reported previously, more recent efforts have been concentrated in technical developments to improve coating compatibility, synthesis procedure scalability, as well as fine tuning the release property of encapsulated active agents.

  12. Corrosion Protection of Nd-Fe Magnets via Phophatization, Silanization and Electrostatic Spraying with Organic Resin Composite Coatings

    Science.gov (United States)

    Ding, Xia; Li, Jingjie; Li, Musen; Ge, Shengsong; Wang, Xiuchun; Ding, Kaihong; Cui, Shengli; Sun, Yongcong

    2014-09-01

    Nd-Fe-B permanent magnets possess excellent properties. However, they are highly sensitive to the attack of corrosive environment. The aim of this work is to improve the corrosion resistance of the magnets by phosphatization, silanization, and electrostatic spraying with organic resin composite coatings. Field emission scanning electron microscope (FE-SEM) and energy dispersive spectrometer (EDS) tests showed that uniform phosphate conversion coatings and spray layers were formed on the surface of the Nd-Fe-B magnets. Neutral salt spray tests exhibited that, after treated by either phosphating, silanization or electrostatic spraying, the protectiveness of Nd-Fe-B alloys was apparently increased. And corrosion performance of magnets treated with silane only was slightly inferior to those of phosphatized ones. However, significant improvement in corrosion protection was achieved after two-step treatments, i.e. by top-coating spray layer with phosphate or silane films underneath. Grid test indicated that the phosphate and silane coating were strongly attached to the substrate while silane film was slightly weaker than the phosphate-treated ones. Magnetic property analysis revealed phosphatization, silanization, and electrostatic spraying caused decrease in magnetism, but silanization had the relatively smaller effect.

  13. The Role of Nanostructured Al2O3 Layer in Reduction of Hot Corrosion Products in Normal YSZ Layer

    Directory of Open Access Journals (Sweden)

    Mohammadreza Daroonparvar

    2013-01-01

    Full Text Available YVO4 crystals and monoclinic ZrO2 are known as hot corrosion products that can considerably reduce the lifetime of thermal barrier coatings during service. The hot corrosion resistance of two types of air plasma sprayed thermal barrier coating systems was investigated: an Inconel 738/NiCrAlY/YSZ (yttria-stabilized zirconia and an Inconel 738/NiCrAlY/YSZ/nano-Al2O3 as an outer layer. Hot corrosion test was accomplished on the outer surface of coatings in molten salts (45% Na2SO4 + 55% V2O5 at 1000°C for 52 hour. It was found that nanostructured alumina as outer layer of YSZ/nano-Al2O3 coating had significantly reduced the infiltration of molten salts into the YSZ layer and resulted in lower reaction of fused corrosive salts with YSZ, as the hot corrosion products had been substantially decreased in YSZ/nano-Al2O3 coating in comparison with normal YSZ coating after hot corrosion process.

  14. Aqueous oxidation reaction enabled layer-by-layer corrosion of semiconductor nanoplates into single-crystalline 2D nanocrystals with single layer accuracy and ionic surface capping.

    Science.gov (United States)

    Ji, Muwei; Xu, Meng; Zhang, Jun; Liu, Jiajia; Zhang, Jiatao

    2016-02-25

    A controllable aqueous oxidation reaction enabled layer-by-layer corrosion has been proposed to prepare high-quality two-dimensional (2D) semiconductor nanocrystals with single layer accuracy and well-retained hexagonal shapes. The appropriate oxidizing agent, such as H2O2, Fe(NO3)3, and HNO3, could not only corrode the layered-crystalline-structured Bi2Te3 nanoplates layer-by-layer to be a single quintuple layer, but also replace the organic barriers to be ionic ligands on the surface synergistically. AFM analysis was used to confirm the layer-by-layer exfoliation from the side to the center. Together with precise XRD, LRTEM and HRTEM characterizations, the controllable oxidation reaction enabled aqueous layer-by-layer corrosion mechanism has been studied.

  15. Enhancement of the corrosion protection of electroless Ni–P coating by deposition of sonosynthesized ZnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Sharifalhoseini, Zahra [Sonochemical Research Center, Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, 91779 Mashhad (Iran, Islamic Republic of); Entezari, Mohammad H., E-mail: entezari@um.ac.ir [Sonochemical Research Center, Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, 91779 Mashhad (Iran, Islamic Republic of); Environmental Chemistry Research Center, Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, 91779 Mashhad (Iran, Islamic Republic of)

    2015-10-01

    Graphical abstract: Enhancement of the corrosion protection of electroless Ni–P layer by ZnO nanoparticles deposition and the comparison with the classical and sonochemical Ni–P coatings. - Highlights: • Unique effects of ultrasound were investigated on the anticorrosive performance of electroless Ni–P coating. • Sonoynthesis of ZnO NPs and its deposition were performed on the surface of Ni–P coating. • ZnO as an anticorrosive has a critical role in the multifunctional surfaces. • Electrochemical properties of all fabricated samples were compared with each other. - Abstract: Ni–P coatings were deposited through electroless nickel plating in the presence and absence of ultrasound. The simultaneous synthesis of ZnO nanoparticle and its deposition under ultrasound were also carried out on the surface of Ni–P layer prepared by the classical method. The morphology of the surfaces and the chemical composition were determined by scanning electron microscopy(SEM) and energy dispersive spectroscopy (EDS), respectively. Electrochemical techniques were applied for the corrosion behavior studies. The Ni–P layer deposited by ultrasound showed a higher anticorrosive property than the layer deposited by the classical method. The ZnO nanoparticles deposited on the surface of Ni–P layer significantly improved the corrosion resistance.

  16. 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

    Science.gov (United States)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

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

  18. 2D Heterostructure coatings of hBN-MoS2 layers for corrosion resistance

    Science.gov (United States)

    Vandana, Sajith; Kochat, Vidya; Lee, Jonghoon; Varshney, Vikas; Yazdi, Sadegh; Shen, Jianfeng; Kosolwattana, Suppanat; Vinod, Soumya; Vajtai, Robert; Roy, Ajit K.; Sekhar Tiwary, Chandra; Ajayan, P. M.

    2017-02-01

    Heterostructures of atomically thin 2D materials could have improved physical, mechanical and chemical properties as compared to its individual components. Here we report, the effect of heterostructure coatings of hBN and MoS2 on the corrosion behavior as compared to coatings employing the individual 2D layer compositions. The poor corrosion resistance of MoS2 (widely used as wear resistant coating) can be improved by incorporating hBN sheets. Depending on the atomic stacking of the 2D sheets, we can further engineer the corrosion resistance properties of these coatings. A detailed spectroscopy and microscopy analysis has been used to characterize the different combinations of layered coatings. Detailed DFT based calculation reveals that the effect on the electrical properties due to atomic stacking is one of the major reasons for the improvement seen in corrosion resistance.

  19. Corrosion Performance of Composite Galvanic Coatings with Variable Concentration of Polymeric Nanoaggregates and/or Cr(III) Conversion Layers

    NARCIS (Netherlands)

    Koleva, D.A.; Taheri, P.; Tsvetkova, N.; Boshkov, N.; Van Breugel, K.; De Wit, J.H.W.; Mol, J.M.C.

    2011-01-01

    This paper reports on the corrosion performance of composite zinc layers (~ 8µm) on a steel substrate, considering the influence of nano-aggregates and Cr(III) conversion layers, compared to control (only Zn layers) conditions. The main factors, influencing the corrosion performance of Zn in this

  20. Corrosion Performance of Composite Galvanic Coatings with Variable Concentration of Polymeric Nanoaggregates and/or Cr(III) Conversion Layers

    NARCIS (Netherlands)

    Koleva, D.A.; Taheri, P.; Tsvetkova, N.; Boshkov, N.; Van Breugel, K.; De Wit, J.H.W.; Mol, J.M.C.

    2011-01-01

    This paper reports on the corrosion performance of composite zinc layers (~ 8µm) on a steel substrate, considering the influence of nano-aggregates and Cr(III) conversion layers, compared to control (only Zn layers) conditions. The main factors, influencing the corrosion performance of Zn in this st

  1. Corrosion protection of steel in ammonia/water heat pumps

    Science.gov (United States)

    Mansfeld, Florian B.; Sun, Zhaoli

    2003-10-14

    Corrosion of steel surfaces in a heat pump is inhibited by adding a rare earth metal salt to the heat pump's ammonia/water working fluid. In preferred embodiments, the rare earth metal salt includes cerium, and the steel surfaces are cerated to enhance the corrosion-inhibiting effects.

  2. Application of Electrochemical Impedance Spectroscopy in the Evaluation of Corrosion and Cathodic Protection in Reinforced Concrete

    NARCIS (Netherlands)

    Koleva, D.A.; Van Breugel, K.; De Wit, J.H.W.; Fraaij, A.L.A.; Boshkov, N.

    2007-01-01

    The electrochemical behavior of steel reinforcement in conditions of corrosion and cathodic protection (CP) was studied, using electrochemical impedance spectroscopy (EIS) and compared to reference (non-corroding) conditions. Polarization resistance (PR) method and potentio-dynamic polarization (PDP

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

    NARCIS (Netherlands)

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

    2007-01-01

    The electrochemical behavior of steel reinforcement in conditions of corrosion and cathodic protection was studied, using electrochemical impedance spectroscopy (EIS) and compared to reference (noncorroding) conditions. Polarization resistance (PR) method and potentiodynamic polarization (PDP) were

  4. Corrosion Protection of Launch Infrastructure and Hardware Through the Space Shuttle Program

    Science.gov (United States)

    Calle, L. M.

    2011-01-01

    Corrosion, the environmentally induced degradation of materials, has been a challenging and costly problem that has affected NASA's launch operations since the inception of the Space Program. Corrosion studies began at NASA's Kennedy Space Center (KSC) in 1966 during the Gemini/Apollo Programs with the evaluation of long-term protective coatings for the atmospheric protection of carbon steel. NASA's KSC Beachside Corrosion Test Site, which has been documented by the American Society of Materials (ASM) as one of the most corrosive, naturally occurring environments in the world, was established at that time. With the introduction of the Space Shuttle in 1981, the already highly corrosive natural conditions at the launch pad were rendered even more severe by the acidic exhaust from the solid rocket boosters. In the years that followed, numerous efforts at KSC identified materials, coatings, and maintenance procedures for launch hardware and equipment exposed to the highly corrosiye environment at the launch pads. Knowledge on materials degradation, obtained by facing the highly corrosive conditions of the Space Shuttle launch environment, as well as limitations imposed by the environmental impact of corrosion control, have led researchers at NASA's Corrosion Technology Laboratory to establish a new technology development capability in the area of corrosion prevention, detection, and mitigation at KSC that is included as one of the "highest priority" technologies identified by NASA's integrated technology roadmap. A historical perspective highlighting the challenges encountered in protecting launch infrastructure and hardware from corrosion during the life of the Space Shuttle program and the new technological advances that have resulted from facing the unique and highly corrosive conditions of the Space Shuttle launch environment will be presented.

  5. Hot Corrosion Behavior of Double-ceramic-layer LaTi2Al9O19/YSZ Thermal Barrier Coatings

    Institute of Scientific and Technical Information of China (English)

    XIE Xiaoyun; GUO Hongbo; GONG Shengkai; XU Huibin

    2012-01-01

    LaTi2Al9O19 (LTA) exhibits promising potential as a new kind of thermal barrier coating (TBC) material,due to its excellent high-temperature capability and low thermal conductivity.In this paper,LTA/yttria stabilized zirconia (YSZ) TBCs are produccd by atmospheric plasma spraying.Hot corrosion behavior and the related failure mechanism of the coating are investigated.Decomposition of LTA does not occur even after 1 458 hot corrosion cycles at 1 373 K,revealing good chemical stability in molten salt of Na2SO4 and NaCl.However,the molten salt infiltrates to the bond coat,causing dissolving of the thermally grown oxide (TGO) in the molten salt and hot corrosion of the bond coat.As a result,cracking of the TBC occurs within the oxide layer.In conclusion,the ceranic materials LTA and YSZ reveal good chemical stability in molten salts of Na2SO4 and NaCl,and the bond coat plays a significant role in providing protection for the component against hot corrosion in the LTA/YSZ TBCs.LTA exhibits very promising potential as a novel TBC material.

  6. Corrosion Protection Performance of Polyester-Melamine Coating with Natural Wood Fiber Using EIS Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Shin, PyongHwa; Shon, MinYoung [Pukyong National University, Busan (Korea, Republic of); Jo, DuHwan [POSCO, Gwangyang (Korea, Republic of)

    2016-04-15

    In the present study, polyester-melamine coating systems with natural wood fiber (NWF) were prepared and the effects of NWF on the corrosion protectiveness of the polyester-melamine coating were examined using EIS analysis. From the results, higher average surface roughness was observed with increase of NWF content. Water diffusivity and water uptake into the polyester-melamine coatings with NWF were much higher than that into the pure polyester-melamine coating. The decrease in the impedance modulus |Z| was associated with the localized corrosion on carbon steel, confirming that corrosion protection of the polyester-melamine coatings with NWF well agrees with its water transport behavior.

  7. In Situ Formation of Decavanadate-Intercalated Layered Double Hydroxide Films on AA2024 and their Anti-Corrosive Properties when Combined with Hybrid Sol Gel Films

    Directory of Open Access Journals (Sweden)

    Junsheng Wu

    2017-04-01

    Full Text Available A layered double hydroxide (LDH film was formed in situ on aluminum alloy 2024 through a urea hydrolysis method, and a decavanadate-intercalated LDH (LDH-V film fabricated through the dip coating method. The microstructural and morphological characteristics were investigated by scanning electron microscopy (SEM. The corrosion-resistant performance was analyzed by electrochemical impedance spectroscopy (EIS, scanning electrochemical microscopy (SECM, and a salt-spray test (SST.The SEM results showed that a complete and defect-free surface was formed on the LDH-VS film. The anticorrosion results revealed that the LDH-VS film had better corrosion-resistant properties than the LDH-S film, especially long-term corrosion resistance. The mechanism of corrosion protection was proposed to consist of the self-healing effect of the decavanadate intercalation and the shielding effect of the sol-gel film.

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

    Science.gov (United States)

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

    2012-04-01

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

  9. Hydrogen-increased dezincification layer-induced stress and susceptibility to stress corrosion cracking of brass

    Institute of Scientific and Technical Information of China (English)

    李会录; 高克玮; 褚武扬; 刘亚萍; 乔利杰

    2003-01-01

    Dezincification layer formed during corrosion or stress corrosion cracking (SCC) of brass in an ammonia solution could induce an additive stress. The effect of hydrogen on the dezincification layer-induced stress and the susceptibility to SCC were studied. The dezincification layer-induced stress was measured using the deflection method and the flowing stress differential method, respectively. The latter measures the difference between the flowing stress of a specimen before unloading and the yield stress of the same specimen after unloading and forming a dezincification layer. The susceptibility to SCC was measured using slow strain rate test. Results show that both the dezincification layer-induced stress and the susceptibility to SCC increase with increasing hydrogen concentration in a specimen. This implies that hydrogen-enhanced dezincification layer-induced stress is consistence with the hydrogen-increased susceptibility to SCC of brass in the ammonia solution.

  10. Graphene Coatings: Probing the Limits of the One Atom Thick Protection Layer

    DEFF Research Database (Denmark)

    Nilsson, Louis; Andersen, Mie; Balog, Richard

    2012-01-01

    The limitations of graphene as an effective corrosion-inhibiting coating on metal surfaces, here exemplified by the hex-reconstructed Pt(100) surface, are probed by scanning tunneling microscopy measurements and density functional theory calculations. While exposure of small molecules directly onto...... the Pt(100) surface will lift the reconstruction, a single graphene layer is observed to act as an effective coating, protecting the reactive surface from O2 exposure and thus preserving the reconstruction underneath the graphene layer in O2 pressures as high as 104 mbar. A similar protective effect...

  11. Low-cost Evaporator Protection Method against Corrosion in a Pulverized Coal Fired Boiler

    Directory of Open Access Journals (Sweden)

    Arkadiusz Krzysztof Dyjakon

    2010-07-01

    Full Text Available Corrosion processes appearing on the watertubes in a combustion chamber of pulverized coal-fired boilers require permanent control and service. Subject to the power plant strategy, different anti-corrosion protection methods can be applied. Technical-economical analysis has been performed to evaluate and support the decisions on maintenance and operation services. The paper presents and discusses results of the application of an air protection system in boiler OP-230 in view of anti-corrosion measures. It is indicated that a low-cost protection method of watertubes (evaporator against corrosion can be efficient and lead to financial savings in comparison to the standard procedure of replacement of watertube panels.

  12. Thin layer activation for probing flow accelerated corrosion of carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, H.; Madasamy, P. [Water and Steam Chemistry Division, BARC Facilities, Kalpakkam 603 102, Tamil Nadu (India); Kumawat, H.; Thomas, R.G. [Nuclear Physics Division, BARC, Mumbai 400 085, Maharashtra (India); Krishnamohan, T.V. [Water and Steam Chemistry Division, BARC Facilities, Kalpakkam 603 102, Tamil Nadu (India); Velmurugan, S., E-mail: svelu@igcar.gov.in [Water and Steam Chemistry Division, BARC Facilities, Kalpakkam 603 102, Tamil Nadu (India); Narasimhan, S.V. [Water and Steam Chemistry Division, BARC Facilities, Kalpakkam 603 102, Tamil Nadu (India)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Corrosion rate in certain locations of feeder piping exceeds the design allowance. Black-Right-Pointing-Pointer Online measurement of localized wall thinning in a short time. Black-Right-Pointing-Pointer Velocity and pH dependence of corrosion rates predicted by Sanchez-Caldera model. Black-Right-Pointing-Pointer Surface roughness corrections mandatory for extrapolation of experimental results. - Abstract: Carbon steel feeder elbows and feeder piping of the primary coolant system of pressurized heavy water reactors undergo significant wall thinning due to flow accelerated corrosion. The rate of corrosion in certain locations exceeds the design corrosion allowance. Corrosion rate is dependent on several parameters like pH, temperature, dissolved oxygen, chromium content in material, pipe geometry, etc. Thin layer activation, utilizing the {sup 57}Fe(p,n){sup 57}Co reaction, enabled rapid online measurement of wall thinning in a simulated straight feeder pipe. Significant velocity and pH dependence was observed for corrosion rates and the same were compared with the predictions by Sanchez-Caldera model.

  13. Smart Coatings for Launch Site Corrosion Protection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Corrosion is a serious problem that has enormous costs for the nation (4.2% GDP in 2007) and worldwide. Kennedy Space Center is located in one of the most naturally...

  14. Self Healing Ultrahydrophobic Coatings for Corrosion Protection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The total annual corrosion related costs in the US has been estimated at greater than $300 billion. Much of these costs are associated with scraping and repainting...

  15. Corrosion-resistant uranium

    Science.gov (United States)

    Hovis, V.M. Jr.; Pullen, W.C.; Kollie, T.G.; Bell, R.T.

    1981-10-21

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  16. Influence of mill scale and rust layer on the corrosion resistance of low-alloy steel in simulated concrete pore solution

    Science.gov (United States)

    Shi, Jin-jie; Ming, Jing

    2017-01-01

    Electrochemical impedance spectroscopy, cyclic potentiodynamic polarization measurements, and scanning electron microscopy in conjunction with energy-dispersive X-ray spectroscopy were used to investigate the influence of mill scale and rust layer on the passivation capability and chloride-induced corrosion behaviors of conventional low-carbon (LC) steel and low-alloy (LA) steel in simulated concrete pore solution. The results show that mill scale exerts different influences on the corrosion resistance of both steels at various electrochemical stages. We propose that the high long-term corrosion resistance of LA steel is mainly achieved through the synergistic effect of a gradually formed compact, adherent and well-distributed Cr-enriched inner rust layer and the physical barrier protection effect of mill scale.

  17. GALVANIC CORROSION AND PROTECTION OF GECM/LY12CZ COUPLES UNDER DIFFERENT ATMOSPHERIC EXPOSURE CONDITIONS

    Institute of Scientific and Technical Information of China (English)

    F. Lu; Q.P. Zhong; C.X. Cao

    2003-01-01

    Galvanic compatibility between graphite epoxy composite materials (GECM) andLY12CZ aluminum alloy was evaluated in different atmospheric corrosion environ-ments and by laboratory electrochemical measurements. Open circuit potential elec-trochemical measurements showed a relatively large potential difference about 1 voltbetween the GECM and LY12CZ aluminum alloy, and this difference provided thedriving force for galvanic corrosion of the LY12CZ aluminum alloy as an anode.Having been exposed for 1, 3 or 5 years in Beijing, Tuandao and Wanning station,GECM/L Y12CZ couples showed significant losses of strength and elongation. Protec-tive coatings and non-conductive barriers breaking the galvanic corrosion circuit wereevaluated under the same atmospheric corrosive conditions. Epoxy primer paint, glasscloth barriers and LY12CZ anodizing were effective in galvanic corrosion control forGECM/L Y12CZ couples.

  18. effect of municipal liquid waste on corrosion susceptibility of ...

    African Journals Online (AJOL)

    DR. AMINU

    The corrosion rate of the galvanized steel pipe was measured using the gravimetric technique. ... three stagnant liquid waste samples collected outside the city (SLW4,SLW5, and ... increased exposure time, a layer of protective corrosion ...

  19. Corrosion protection of Mg/Al alloys by thermal sprayed aluminium coatings

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, A., E-mail: anpardo@quim.ucm.es [Departamento de Ciencia de Materiales, Facultad de Quimicas, Universidad Complutense, 28040 Madrid (Spain); Casajus, P.; Mohedano, M.; Coy, A.E.; Viejo, F. [Departamento de Ciencia de Materiales, Facultad de Quimicas, Universidad Complutense, 28040 Madrid (Spain); Torres, B. [Departamento de Ciencia e Ingenieria de Materiales, ESCET, Universidad Rey Juan Carlos, 28933 Mostoles, Madrid (Spain); Matykina, E. [Corrosion and Protection Centre, School of Materials, The University of Manchester, P.O. Box 88, Sackville Street, Manchester M60 1QD (United Kingdom)

    2009-05-15

    The protective features of thermal sprayed Al-coatings applied on AZ31, AZ80 and AZ91D magnesium/aluminium alloys were evaluated in 3.5 wt.% NaCl solution by electrochemical and gravimetric measurements. The changes in the morphology and corrosion behaviour of the Al-coatings induced by a cold-pressing post-treatment were also examined. The specimens were characterized by scanning electron microscopy, energy dispersive X-ray analysis and low-angle X-ray diffraction. The as-sprayed Al-coatings revealed a high degree of porosity and poor corrosion protection, which resulted in galvanic acceleration of the corrosion of the magnesium substrates. The application of a cold-pressing post-treatment produced more compact Al-coatings with better bonding at the substrate/coating interface and higher corrosion resistance regardless of the nature of the magnesium alloy.

  20. The corrosion protection of 6061-T6 aluminum by a polyurethane-sealed anodized coat

    Science.gov (United States)

    Danford, M. D.

    1990-01-01

    The corrosion protection of 6061-T6 anodized aluminum afforded by a newly patented polyurethane seal was studied using the ac impedance technique. Values of the average corrosion rates over a 27-day exposure period in 3.5 percent NaCl solutions at pH 5.2 and pH 9.5 compared very favorably for Lockheed-prepared polyurethane-sealed and dichromate-sealed coats of the same thickness. Average corrosion rates for both specimens over the first 7 days of exposure compared well with those for a hard anodized, dichromate-sealed coat, but rose well above those for the hard anodized coat over the entire 27-day period. This is attributed both to the greater thickness of the hard anodized coat, and possibly to its inherently better corrosion protective capability.

  1. Plasma chemical reduction of model corrosion brass layers prepared in soil

    Science.gov (United States)

    Radkova, Lucie; Mikova, Petra; Prikryl, Radek; Krcma, Frantisek

    2016-08-01

    The brass plates of (50 × 10 × 1) mm3 were prepared with model corrosion layer because the real archaeological artifacts could be damaged during the method optimization. Samples corroded naturally more than 2 years in the soil. Excavated samples were treated in the low pressure (150 Pa) quartz glass plasma reactor (90 cm long and 9.5 cm in diameter) which was surrounded by two external copper electrodes supplied by radio-frequency generator (13.56 MHz). The experiments were carried out in a hydrogen-argon gas mixture at mass flows of 30 sccm for hydrogen and 20 sccm for argon for 90 min. The plasma power was 100, 200, 300 and 400 W in continuous and pulsed mode. Maximum sample temperature was set at 120 °C. The whole process was monitored by optical emission spectroscopy and the obtained data were used to calculate the relative intensity of OH radicals and rotational temperature. The results showed that the higher power had the greater maximum intensity of the OH radicals and rapidly degraded the corrosion layer. Corrosion layer was not completely removed during the reduction, but due to the reactions which occur in the plasma corrosion layer became brittle and after plasma chemical treatment can be removed easily. Finally, the SEM-EDX analysis of the surface composition confirmed removal of chlorine and oxygen from the corrosion products layers. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-05-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-15

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

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    /SS, both samples exhibiting a similar trend, thus questioning the short-term positive effect of graphene coatings. However, partial immersion in boiling seawater for three weeks reveals a clear superiority of the graphene coating with respect to steel just protected by Ni. After the test, the graphene film......Abstract Motivated by similar investigations recently published (Pu et al., 2015), we report a comparative corrosion study of three sets of samples relevant as bipolar plates for polymer electrolyte fuel cells: stainless steel, stainless steel with a nickel seed layer (Ni/SS) and stainless steel...

  5. Insitu grown superhydrophobic Zn–Al layered double hydroxides films on magnesium alloy to improve corrosion properties

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Meng; Pang, Xiaolu; Wei, Liang; Gao, Kewei, E-mail: kwgao@yahoo.com

    2015-05-15

    Highlights: • Hierarchical superhydrophobic Zn–Al LDHs film has been fabricated on a magnesium alloy substrate. • The superhydrophobic surface has good long-term stability under atmospheric environment. • The superhydrophobic surface can provide a stable corrosion protection for the Mg alloys. - Abstract: A hierarchical superhydrophobic zinc–aluminum layered double hydroxides (Zn–Al LDHs) film has been fabricated on a magnesium alloy substrate via a facile hydrothermal crystallization method following chemical modification. The characteristics of the films were investigated by X-ray diffraction (XRD), scanning electronic microscope (SEM), and energy dispersive spectroscopy (EDS). XRD patterns and SEM images showed that the micro/nanoscale hierarchical LDHs film surfaces composed of ZnO nanorods and Zn–Al LDHs nanowalls structures. The static contact angle (CA) for the prepared surfaces was observed at around 165.6°. The corrosion resistance of the superhydrophobic films was estimated by electrochemical impedance spectroscopy (EIS) and potentiondynamic polarization measurement. EIS and polarization measurements revealed that the superhydrophobic Zn–Al LDHs coated magnesium alloy had better corrosion resistance in neutral 3.5 wt.% NaCl solution.

  6. Corrosion behavior of rebar for intermittent cathodic protection of coastal bridges

    Energy Technology Data Exchange (ETDEWEB)

    Ziomek-Moroz, M. | Cramer, S.D. | Covino, B.S., Jr. | Bullard, S.J. | Holcomb, G.R. | Russell, J.H. | Windisch, Jr., C.F. (PNNL)

    2001-02-01

    A number of reinforced concrete bridges on the Oregon coast are protected against chloride-induced corrosion damage by means of impressed current cathodic protection (ICCP). Thermal-sprayed Zn serves as the anode in these systems. Rebar in the concrete can remain passive and protected for some period of time after the CP system is turned off. The active-passive corrosion behavior of rebar in simulated pore solution (SPS) was investigated as a function of pH and Cl- concentration as part of a study of intermittent ICCP operation. Rebar corrosion rates in SPS were determined from polarization curves by fitting the Butler-Volmer equation and the linear polarization equation. Analysis of the passive film in SPS by x-ray diffraction and surface enhanced Raman spectroscopy showed it to be largely Fe3O4. However, the Fe(OH)2 content increased with cathodic polarization time.

  7. Green Inhibitors for Corrosion Protection of Metals and Alloys: An Overview

    Directory of Open Access Journals (Sweden)

    B. E. Amitha Rani

    2012-01-01

    Full Text Available Corrosion control of metals is of technical, economical, environmental, and aesthetical importance. The use of inhibitors is one of the best options of protecting metals and alloys against corrosion. The environmental toxicity of organic corrosion inhibitors has prompted the search for green corrosion inhibitors as they are biodegradable, do not contain heavy metals or other toxic compounds. As in addition to being environmentally friendly and ecologically acceptable, plant products are inexpensive, readily available and renewable. Investigations of corrosion inhibiting abilities of tannins, alkaloids, organic,amino acids, and organic dyes of plant origin are of interest. In recent years, sol-gel coatings doped with inhibitors show real promise. Although substantial research has been devoted to corrosion inhibition by plant extracts, reports on the detailed mechanisms of the adsorption process and identification of the active ingredient are still scarce. Development of computational modeling backed by wet experimental results would help to fill this void and help understand the mechanism of inhibitor action, their adsorption patterns, the inhibitor-metal surface interface and aid the development of designer inhibitors with an understanding of the time required for the release of self-healing inhibitors. The present paper consciously restricts itself mainly to plant materials as green corrosion inhibitors.

  8. Improved mechanical and corrosion properties of nickel composite coatings by incorporation of layered silicates

    Energy Technology Data Exchange (ETDEWEB)

    Tientong, J. [University of North Texas, Department of Chemistry, 1155 Union Circle #305070, Denton, TX 76203 (United States); Ahmad, Y.H. [Center for Advanced Materials, P.O. Box 2713, Qatar University, Doha (Qatar); Nar, M.; D' Souza, N. [University of North Texas, Department of Mechanical and Energy Engineering, Denton, TX 76207 (United States); Mohamed, A.M.A. [Center for Advanced Materials, P.O. Box 2713, Qatar University, Doha (Qatar); Golden, T.D., E-mail: tgolden@unt.edu [University of North Texas, Department of Chemistry, 1155 Union Circle #305070, Denton, TX 76203 (United States)

    2014-05-01

    Layered silicates as exfoliated montmorillonite are incorporated into nickel films by electrodeposition, enhancing both corrosion resistance and hardness. Films were deposited onto stainless steel from a plating solution adjusted to pH 9 containing nickel sulfate, sodium citrate, and various concentrations of exfoliated montmorillonite. The presence of the incorporated layered silicate was confirmed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The composite films were also compact and smooth like the pure nickel films deposited under the same conditions as shown by scanning electron microscopy. X-ray diffraction results showed that incorporation of layered silicates into the film do not affect the nickel crystalline fcc structure. The nanocomposite films exhibited improved stability and adhesion. Pure nickel films cracked and peeled from the substrate when immersed in 3.5% NaCl solution within 5 days, while the nanocomposite films remained attached even after 25 days. The corrosion resistance of the nickel nanocomposites was also improved compared to nickel films. Nickel-layered silicate composites showed a 25% increase in Young's modulus and a 20% increase in hardness over pure nickel films. - Highlights: • 0.05–2% of layered silicates are incorporated into crystalline nickel films. • Resulting composite films had improved stability and adhesion. • Corrosion resistance improved for the composite films. • Hardness improved 20% and young's modulus improved 25% for the composite films.

  9. Failure behavior of protective organic coatings under corrosive conditions

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xian-cheng; XU Bin-shi; WANG Hai-dou; WU Yi-xiong

    2004-01-01

    Recent research activities on the formation of micro-defects and porosity in organic coatings were reviewed. The mechanisms of aggressive ionic conduction through organic coatings were analyzed. The micro-mechanisms for the failure behavior of coatings under corrosive environments were discussed in detail. These mechanisms included blistering (i. e. osmotic blistering, anodic blistering and cathodic blistering) in the coating, wet-adhesion loss at the substrate/coating interface, cathodic delamination of coating from the substrate. Based on these researches, it was found that the failure behavior of organic coatings is closely related to the micro-defects in coatings, regardless of the failure mode. Additionally, the general failure mode of a coating system was proposed to interpret the failure behavior of organic in corrosion environments. The topics discussed can provide some insights into the development of a methodology for designing fail-safe coating systems.

  10. Corrosion Control of Kunifer-5 Seawater Piping Systems of Naval Ships by Cathodic Protection Technique

    Directory of Open Access Journals (Sweden)

    M. B. Deshmukh

    1982-01-01

    Full Text Available The cause of premature corrosion of Kunifer-5(copper alloy containing Ni 5 per cent and Fe 1.35 per cent pipes used in seawater piping systems on board ships for feeding seawater to various units has been discussed. It has been shown that the Kunifer-5 alloys suffer from heavy corrosion-erosion attack at unavoidable bends and places where local seawater velocity exceeds the specified limit. The field observations as well as laboratory study have indicated that satisfactory protection of the pipes could be achieved by galvanic cathodic protection using aluminium alloy anodes.

  11. Molybdenum Disulfide as a Protection Layer and Catalyst for Gallium Indium Phosphide Solar Water Splitting Photocathodes.

    Science.gov (United States)

    Britto, Reuben J; Benck, Jesse D; Young, James L; Hahn, Christopher; Deutsch, Todd G; Jaramillo, Thomas F

    2016-06-02

    Gallium indium phosphide (GaInP2) is a semiconductor with promising optical and electronic properties for solar water splitting, but its surface stability is problematic as it undergoes significant chemical and electrochemical corrosion in aqueous electrolytes. Molybdenum disulfide (MoS2) nanomaterials are promising to both protect GaInP2 and to improve catalysis because MoS2 is resistant to corrosion and also possesses high activity for the hydrogen evolution reaction (HER). In this work, we demonstrate that GaInP2 photocathodes coated with thin MoS2 surface protecting layers exhibit excellent activity and stability for solar hydrogen production, with no loss in performance (photocurrent onset potential, fill factor, and light-limited current density) after 60 h of operation. This represents a 500-fold increase in stability compared to bare p-GaInP2 samples tested in identical conditions.

  12. Molybdenum Disulfide as a Protection Layer and Catalyst for Gallium Indium Phosphide Solar Water Splitting Photocathodes

    Energy Technology Data Exchange (ETDEWEB)

    Britto, Reuben J.; Benck, Jesse D.; Young, James L.; Hahn, Christopher; Deutsch, Todd G.; Jaramillo, Thomas F.

    2016-06-02

    Gallium indium phosphide (GaInP2) is a semiconductor with promising optical and electronic properties for solar water splitting, but its surface stability is problematic as it undergoes significant chemical and electrochemical corrosion in aqueous electrolytes. Molybdenum disulfide (MoS2) nanomaterials are promising to both protect GaInP2 and to improve catalysis since MoS2 is resistant to corrosion and also possesses high activity for the hydrogen evolution reaction (HER). In this work, we demonstrate that GaInP2 photocathodes coated with thin MoS2 surface protecting layers exhibit excellent activity and stability for solar hydrogen production, with no loss in performance (photocurrent onset potential, fill factor, and light limited current density) after 60 hours of operation. This represents a five-hundred fold increase in stability compared to bare p-GaInP2 samples tested in identical conditions.

  13. The influence of time-variable cathodic corrosion protection on a.c. corrosion; Einfluss von zeitlich variierendem kathodischem Korrosionsschutz auf die Wechselstromkorrosion

    Energy Technology Data Exchange (ETDEWEB)

    Buechler, Markus; Voute, Carl-Heinz; Joos, David [SGK Schweizerische Gesellschaft fuer Korrosionsschutz, Zuerich (Switzerland)

    2011-07-01

    The current limiting values for corrosion of pipelines under a.c. current stress may be difficult to apply to pipelines, owing to the very heterogeneous bedding of the pipeline, poor jacket quality, or high short-term a.c. voltages. In principle, periodic alternation between very high and very low protective currents may optimize cathodic corrosion protection. This pulsed current strategy was found to be effective in laboratory tests if the operating parameters are set accurately.

  14. A single precursor pit for pitting corrosion on defect of tinplate alloy layer visualized by atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cui Guofeng [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China)]. E-mail: cuiguofeng@hit.edu.cn; Wang Jinghe [Research of Precise Engineering, Harbin Institute of Technology, Harbin 150001 (China); Li Ning [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Huang Xingqiao [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China)

    2006-06-10

    The gray points highly disperse on the alloy layer surface after free tin coating removed on poorly corrosion-resistant tinplate. The morphology and composition of normal area and the gray point were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and energy dispersion spectroscopy (EDS) on the same tinplate sheet. Additional, the cyclic voltammetry results indicate that corrosion resistance of alloy layer containing gray points is less than that of normal area. Those indicate that gray points are defects of Sn-Fe alloy layer. AFM was applied to obtain detail information on topography change of the gray point in electrolyte. Furthermore, profile lines of the sample at varied time were determined and delivered additional arguments for corrosion rate of the gray point. The results of a single pit corrosion measurement show that corrosion rate is determined by a mass-transport controlled mechanism in acid electrolyte.

  15. Micro-EDXRF surface analyses of a bronze spear head: Lead content in metal and corrosion layers

    Energy Technology Data Exchange (ETDEWEB)

    Figueiredo, E. [Instituto Tecnologico e Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); Departamento de Conservacao e Restauro, Faculdade de Ciencias e Tecnologia da Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Monte de Caparica (Portugal)], E-mail: elin@itn.pt; Valerio, P.; Araujo, M.F. [Instituto Tecnologico e Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); Senna-Martinez, J.C. [Instituto de Arqueologia, Faculdade de Letras da Universidade de Lisboa, Cidade Universitaria, Campo Grande, 1600-214 Lisbon (Portugal)

    2007-09-21

    A bronze spear head from Central Portugal dated to Late Bronze Age has been analyzed by non-destructive micro-EDXRF in the metal surface and corrosion layers. The artifact had previously been analyzed using a conventional EDXRF spectrometer having a larger incident beam. The quantification of the micro-EDXRF analyses showed that lead content in corrosion layers can reach values up to four times higher than the content determined in the metal surface. Results obtained with the higher energy incident beam from the EDXRF equipment, although referring mainly to the corrosion layers, seem to suffer some influence from the surface composition of the metallic alloy.

  16. Nanoscale coatings for erosion and corrosion protection of copper microchannel coolers for high powered laser diodes

    Science.gov (United States)

    Flannery, Matthew; Fan, Angie; Desai, Tapan G.

    2014-03-01

    High powered laser diodes are used in a wide variety of applications ranging from telecommunications to industrial applications. Copper microchannel coolers (MCCs) utilizing high velocity, de-ionized water coolant are used to maintain diode temperatures in the recommended range to produce stable optical power output and control output wavelength. However, aggressive erosion and corrosion attack from the coolant limits the lifetime of the cooler to only 6 months of operation. Currently, gold plating is the industry standard for corrosion and erosion protection in MCCs. However, this technique cannot perform a pin-hole free coating and furthermore cannot uniformly cover the complex geometries of current MCCs involving small diameter primary and secondary channels. Advanced Cooling Technologies, Inc., presents a corrosion and erosion resistant coating (ANCERTM) applied by a vapor phase deposition process for enhanced protection of MCCs. To optimize the coating formation and thickness, coated copper samples were tested in 0.125% NaCl solution and high purity de-ionized (DIW) flow loop. The effects of DIW flow rates and qualities on erosion and corrosion of the ANCERTM coated samples were evaluated in long-term erosion and corrosion testing. The robustness of the coating was also evaluated in thermal cycles between 30°C - 75°C. After 1000 hours flow testing and 30 thermal cycles, the ANCERTM coated copper MCCs showed a corrosion rate 100 times lower than the gold plated ones and furthermore were barely affected by flow rates or temperatures thus demonstrating superior corrosion and erosion protection and long term reliability.

  17. Enhancement of corrosion protection efficiency of iron by poly(aniline-co-amino-naphthol-sulphonic acid) nanowires coating in highly acidic medium

    Energy Technology Data Exchange (ETDEWEB)

    Bhandari, Hema [Polymeric and Soft Materials Section National Physical Laboratory (CSIR) Dr. K. S. Krishnan, Road New Delhi, 110 012 (India); Centre for Polymer Science and Engineering, Indian Institute of Technology New Delhi, 110, 016 (India); Srivastav, Ritu [Polymeric and Soft Materials Section National Physical Laboratory (CSIR) Dr. K. S. Krishnan, Road New Delhi, 110 012 (India); Choudhary, Veena [Centre for Polymer Science and Engineering, Indian Institute of Technology New Delhi, 110, 016 (India); Dhawan, S.K., E-mail: skdhawan@mail.nplindia.ernet.i [Polymeric and Soft Materials Section National Physical Laboratory (CSIR) Dr. K. S. Krishnan, Road New Delhi, 110 012 (India)

    2010-11-30

    Nanowires of copolymers film based on aniline and 1-amino-2-naphthol-4-sulphonic acid were electrochemically synthesized on the iron electrode by cyclic voltammetry using oxalic acid as a supporting electrolyte. Protective properties of copolymer film on the iron surface in 1.0 M HCl solution was investigated by chronoamperometry, potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The results showed that the copolymer film showed the significant shifting in the corrosion potential and greater charge transfer resistance. Moreover, the copolymer showed the larger degree of surface coverage onto the iron surface, reflecting the higher protection for corrosion of the iron in acidic medium. In addition, the film constitutes a physical as well as a chemical barrier layer due to the presence of -OH and -NH groups in ANSA unit, which provides passivity protection in polymer coatings. The mechanism of corrosion protection of iron by these copolymers was investigated by surface morphology and EIS techniques. In addition, by using scanning electron microscopy, the effect of morphology of copolymer on corrosion protection of metal was investigated.

  18. Characterization of corrosion layers on irradiated and non-irradiated surfaces in BWR conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kysela, J.; Balek, V.; Zmitko, M.; Brozova, A.; Burda, J. [Nuclear Research Inst., Rez (Czech Republic); Hoffmann, H.; Ruehle, W. [VGB Essen (Germany); Bezdicka, P. [Institute of Inorganic Chemistry, ASCR, Rez (Czech Republic)

    2002-07-01

    Stress corrosion cracking of low-alloyed steel 22NiMoCr37 is evaluated with the goal to determine crack growth rate in irradiated steel under conditions simulating closely conditions of BWR RPV under operation. For the experiment, in pile BWR experimental loop has been built at Nuclear Research Institute, Rez. During the experiment, specimens are loaded by cyclic and constant load. Crack growth is monitored by means of potential drop measurement and COD. Corrosion layers formed on specimens in reactor water loop exposed to BWR primary water chemistry and radiation were studied. Two sets of specimens were placed in loop channels. One set of specimens was situated in reactor conditions and the second set out of reactor, other parameters like water chemistry (e.g. concentration of hydrogen, oxygen and conductivity), temperature and flow rate were identical. By means of this an effect of radiation could be studied. The differences in chemical composition, structure and microstructure of corrosion products were characterized by SEM and X-ray powder diffractometry. The differences in microstructure of corrosion layer formed under different conditions were observed. (authors)

  19. Understanding Passive Layer Formation for Further Corrosion Management in Gas Production Pipes

    Science.gov (United States)

    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.

  20. Duplex Al-based thermal spray coatings for corrosion protection in high temperature refinery applications

    Directory of Open Access Journals (Sweden)

    Rocha Adriana da Cunha

    2004-01-01

    Full Text Available The application of thermal spray coatings has been effective in preventing corrosion of steel and iron products. It has been used in a wide range of applications spreading from the petroleum to the food industry. In this work, the performance and effectiveness of a two-layered aluminum-based thermal spray coating applied to an ASTM A387 G11 steel was evaluated. The coating structure was comprised of an inner Al-Fe-Cr layer and an outer layer of aluminum. Coated samples were tested in the reactor zone of a fluid catalytic cracking unit (FCCU of a petrochemical plant for 2.5 years. The reactor zone temperature was about 793 K (520 °C and the environment was a mixed gas containing sulfur, oxygen and carbon. Laboratory-scale tests were also conducted on the coated samples in order to gain a better understanding of the corrosive effect of the gaseous species present in the FCCU atmosphere. Porosity present in the thermal spray coatings allowed the penetration of the atmosphere corrodents, which instigated intergranular corrosion of the steel substrate. The presence of an inner Al-Fe-Cr layer did not prevent coating spallation, which further contributed to the internal corrosion process.

  1. Corrosion protection of copper by a self-assembled monolayer of alkanethiol

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Y.; Teo, W.K.; Siow, K.S.; Gao, Z.; Tan, K.L.; Hsieh, A.K. [National Univ. of Singapore (Singapore)

    1997-01-01

    A self-assembled monolayer of 1-dodecanethiol (DT) was formed on a copper surface pretreated using different methods. The corrosion protection abilities of the monolayer were evaluated in an air-saturated 0.51 M NaCl solution using various techniques including electrochemical impedance spectroscopy, polarization, coulometry, weight loss, and X-ray photoelectron spectroscopy. It was found that the corrosion resistance of the monolayer was improved markedly by using a nitric acid etching method. A minimum concentration of 10{sup {minus}4} M DT was needed to form a protective monolayer. The DT-monolayer retarded the reduction of dissolved oxygen and inhibited the growth of copper oxide in the NaCl solution. In comparison with other inhibitors, such as benzotriazole (BTA) and mercapto-benzothiazole (MBT), the DT-monolayer showed much better corrosion resistance in aqueous solution.

  2. Analysis of corrosion layers in ancient Roman silver coins with high resolution surface spectroscopic techniques

    Energy Technology Data Exchange (ETDEWEB)

    Keturakis, Christopher J. [Operando Molecular Spectroscopy and Catalysis Research Laboratory, Department of Chemical Engineering, Lehigh University, Bethlehem, PA 18015 (United States); Notis, Ben [Brandeis University, Waltham, MA 02453 (United States); Blenheim, Alex [Department of Mechanical Engineering, Pennsylvania State University, College Park, PA 16802 (United States); Miller, Alfred C.; Pafchek, Rob [Zettlemoyer Center for Surface Studies, Lehigh University, Bethlehem, PA 18015 (United States); Notis, Michael R., E-mail: mrn1@lehigh.edu [Department of Materials Science and Engineering, Lehigh University, Bethlehem, PA 18015 (United States); Wachs, Israel E., E-mail: iew0@lehigh.edu [Operando Molecular Spectroscopy and Catalysis Research Laboratory, Department of Chemical Engineering, Lehigh University, Bethlehem, PA 18015 (United States)

    2016-07-15

    Highlights: • Five ancient silver alloy coins (225 BCE–244 CE) were analyzed using surface characterization techniques. • Both destructive and non-destructive surface characterization methods were developed. • Alloying with copper, even in small amounts, leads to the formation of an outer Cu{sub 2}O corrosion layer. - Abstract: Determination of the microchemistry of surface corrosion layers on ancient silver alloy coins is important both in terms of understanding the nature of archaeological environmental conditions to which these ancient coins were exposed and also to help in their conservation. In this present study, five ancient silver alloy coins (225 BCE–244 CE) were used as test vehicles to measure their immediate surface microchemistry and evaluate the appropriateness and limitations of High Sensitivity-Low Energy Ion Scattering Spectroscopy (HS-LEIS, 0.3 nm depth analysis), High Resolution-X-ray Photoelectron Spectroscopy (HR-XPS, 1–3 nm depth analysis) and High Resolution-Raman Spectroscopy (HR-Raman, ∼1000 nm depth analysis). Additional information about the deeper corrosion layers, up to ∼300–1000 nm, was provided by dynamic HS-LEIS and HR-Raman spectroscopy. While not archeologically significant, the use of these coins of small commercial value provides data that is more representative of the weaker signals typically obtained from ancient corroded objects, which can be in stark contrast to pristine data often obtained from carefully prepared alloys of known composition. The oldest coins, from 225 to 214 BCE, possessed an outermost surface layer containing Cu{sub 2}O, Na, Al, Pb, and adsorbed hydrocarbons, while the more recent coins, from 98 to 244 CE, contained Cu{sub 2}O, Ag, N, F, Na, Al, S, Cl, and adsorbed hydrocarbons in similar corresponding surface layers. It thus appears that alloying with copper, even in small amounts, leads to the formation of an outer Cu{sub 2}O layer. Depth profiling revealed the presence of K, Na, Cl, and

  3. Architectural optimization of an epoxy-based hybrid sol-gel coating for the corrosion protection of a cast Elektron21 magnesium alloy

    Science.gov (United States)

    Murillo-Gutiérrez, N. V.; Ansart, F.; Bonino, J.-P.; Kunst, S. R.; Malfatti, C. F.

    2014-08-01

    An epoxy-based hybrid sol-gel coating was prepared in various architectural configurations has been studied for the corrosion protection of a cast Elektron21 magnesium alloy. The creation of a single layer of this coating presents defects consisting of macro-pores and protuberances, which opens access for corrosive species to reach the metallic substrate. These defects are suspected to result from the high reactivity of the substrate, as well as to the irregular topography of the substrate disrupted by the microstructure of the own magnesium alloy. Hence, a sol-gel coating in bilayer architecture is proposed, where the first layer would “inert” the surface of the magnesium substrate, and the second layer would cover the defects of the first layer and also thickening the coating. The morphological characteristics of the sol-gel coatings were analyzed by scanning electron microscopy (SEM), and their corrosion behavior was evaluated by OCP (open circuit potential) monitoring and electrochemical impedance spectroscopy (EIS) in chloride media. It is shown that both the architectural arrangement and the individual thickness of the first and second layers have an important influence on the anticorrosion performances of the protective system, just as much as its global thickness.

  4. Architectural optimization of an epoxy-based hybrid sol–gel coating for the corrosion protection of a cast Elektron21 magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Murillo-Gutiérrez, N.V., E-mail: murillo@chimie.ups-tlse.fr [Université de Toulouse UPS-INP-CNRS, Institut Carnot CIRIMAT, Toulouse (France); Ansart, F.; Bonino, J-P. [Université de Toulouse UPS-INP-CNRS, Institut Carnot CIRIMAT, Toulouse (France); Kunst, S.R.; Malfatti, C.F. [Universidade Federal do Rio grande do Sul, Laboratory of Corrosion Research (LAPEC), Porto Alegre (Brazil)

    2014-08-01

    An epoxy-based hybrid sol–gel coating was prepared in various architectural configurations has been studied for the corrosion protection of a cast Elektron21 magnesium alloy. The creation of a single layer of this coating presents defects consisting of macro-pores and protuberances, which opens access for corrosive species to reach the metallic substrate. These defects are suspected to result from the high reactivity of the substrate, as well as to the irregular topography of the substrate disrupted by the microstructure of the own magnesium alloy. Hence, a sol–gel coating in bilayer architecture is proposed, where the first layer would “inert” the surface of the magnesium substrate, and the second layer would cover the defects of the first layer and also thickening the coating. The morphological characteristics of the sol–gel coatings were analyzed by scanning electron microscopy (SEM), and their corrosion behavior was evaluated by OCP (open circuit potential) monitoring and electrochemical impedance spectroscopy (EIS) in chloride media. It is shown that both the architectural arrangement and the individual thickness of the first and second layers have an important influence on the anticorrosion performances of the protective system, just as much as its global thickness.

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

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

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

  6. Corrosion behaviors of TiO{sub 2} nanotube layers on titanium in Hank's solution

    Energy Technology Data Exchange (ETDEWEB)

    Yu Weiqiang; Qiu Jing; Xu Ling; Zhang Fuqiang, E-mail: fredzc@online.sh.c [Department of Prosthodontics, Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, 200011 (China)

    2009-12-15

    It is well known that the growth of osteoblast cultured on titanium with nanotube layers can be significantly increased compared to unanodized surfaces. In the current study, the corrosion behavior of titanium with nanotube layers was studied in naturally aerated Hank's solution using open circuit potentials (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests. The electrochemical results indicated that TiO{sub 2} nanotube layers on titanium showed a better corrosion resistance in simulated biofluid than that of smooth-Ti. The OCP, corrosion rate (I{sub corr}), passive current density (I{sub pass}) and the oxygen evolution potential (E{sub o}) were significantly influenced by titanium oxide nanotube layers acquired by anodization. The anatase nanotube layer showed higher OCP and smaller current density than the amorphous nanotube layer. EIS analysis showed that the annealing had a significant effect on the corrosion resistance of the outer tube layer (R{sub t}), but little effect on the corrosion resistance of the inter-barrier layer (R{sub b}) for nanotube layers. The results suggested that titanium with TiO{sub 2} nanotube layers has an adequate electrochemical behavior for use as a dental implant material.

  7. TiO2 membranes for concurrent photocatalytic organic degradation and corrosion protection

    Science.gov (United States)

    Liang, Robert; Hatat-Fraile, Melisa; He, Horatio; Arlos, Maricor; Servos, Mark R.; Zhou, Y. Norman

    2015-10-01

    Organic contaminants and corrosion in water treatment effluents are a current global problem and the development of effective methods to facilitate the removal of organic contaminants and corrosion control strategies are required to mitigate this problem. TiO2 nanomaterials that are exposed to UV light can generate electron-hole pairs, which undergo redox reactions to produce hydroxyl radicals from adsorbed molecular oxygen. They hydroxyl radicals are able to oxidize organic contaminants in water. This same process can be used in conjunction to protect metals from corrosion via cathodic polarization. In this work, TiO2 nanomaterials were synthesized and electrophoretically deposited on conductive substrates to serve as films or membranes. An illuminated TiO2 film on a conductive surface served as the photoanode and assisted in the cathodic protection of stainless steel (SS304) and the degradation of organic pollutants, in this case glucose. This proof-of-concept relied on photoelectrochemical experiments conducted using a potentiostat and a xenon lamp illumination source. The open-circuit potential changes that determine whether a metal is protected from corrosion under illumination was observed; and the electrical characteristics of the TiO2 film or membrane under dark and arc lamp illumination conditions were also analyzed. Furthermore, the effect of organic contaminants on the photocathodic protection mechanism and the oxidation of glucose during this process were explored.

  8. Possibilities for improving corrosion protection of reinforced concrete by modified hydrotalcites: a literature review

    NARCIS (Netherlands)

    Yang, Z.; Fischer, H.R.; Polder, R.B.

    2012-01-01

    Modified Hydrotalcites (MHTs) represent a group of technologically promising materials for improving corrosion protection in concrete owing to their low cost, relative simplicity of preparation, and plenty of composition variables. Numerous academic and commercial studies on MHTs have been carried o

  9. Corrosion and wear protective composition modulated alloy coatings based on ternary Ni-P-X alloys

    DEFF Research Database (Denmark)

    Leisner, P.; Benzon, M. E.; Christoffersen, Lasse

    1996-01-01

    Scattered reporting in the litterature describes a number of ternary Ni-P-X alloyes (where X can be Co, Cr, Cu, Mo, Pd, Re or W) with promising corrosin and wear protective performance. Based on a systematic study of Ni-P-X alloys it is the intention to produce coatings with improved corrosion...

  10. Corrosion resistance of pseudo-spin-valve systems: Pd vs. Ta capping layers

    Science.gov (United States)

    Matthes, P.; Albrecht, M.

    2016-08-01

    An analysis of both magnetic and magneto-transport properties in dependence of the corrosion resistance is presented for a pseudo-spin-valve (PSV) system with different capping layers. The magnetoresistive part of the sample consists of a [Co/Pd] multilayer with perpendicular magnetic anisotropy and a single Co layer with in-plane easy axis separated by a Cu spacer, forming a PSV system with crossed anisotropies. The samples were annealed under ambient conditions up to temperatures of 200 °C to facilitate the corrosion process. Whereas the magnetic properties are stable up to 100 °C independent of the capping layer, the giant magnetoresistance (GMR) effect is more sensitive on annealing. In case of Pd as capping layer, the GMR of the pseudo-spin-valve considerably degrades already after annealing at 60 °C, whereby even by thickening of the Pd layer up to 10 nm, no pronounced improvement was obtained. On the contrary, for Ta as capping layer the GMR ratio stays constant upon heating up to 100 °C, followed by a comparable moderate decay for even higher annealing temperatures.

  11. Numerical modeling of stray current corrosion of ductile iron pipe induced by foreign cathodic protection system

    Science.gov (United States)

    Li, SeonYeob; Kim, Young-Geun

    2013-07-01

    Stray current corrosion phenomena of ductile iron pipe (DIP) located in the vicinity of cathodically protected steel pipe was assessed using the boundary element method. When all joints in DIP were electrically connected, the maximum corrosion rate was 0.005 mm/y. However, when the joints were isolated, the corrosion rate increased due to the jumping effect of stray current at isolated joints, which resulted in the increase of maximum corrosion rate to 0.87 mm/y at the isolated point. Moreover, the electrical bonding between the DIP and steel pipe could not act effectively but showed an adverse effect of collecting more cathodic protection (CP) currents into the DIP, which eventually jumped out into the soil and resulted in larger amount of stray current corrosion. Therefore it is desirable to apply control methods from the design and construction stage, which include the increase of anodebed and the pipe distance, electrical connection of DIP joints, installation of sacrificial anode at isolated joints, or the application of CP on DIP, etc.

  12. Enhanced wear and corrosion resistance of plasma electrolytic carburized layer on T8 carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jie; Wang, Bin; Zhang, Yifan; Liu, Run [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Xia, Yuan; Li, Guang [Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China); Xue, Wenbin, E-mail: xuewb@bnu.edu.cn [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2016-03-01

    A hardening layer of 70 μm on T8 carbon steel was fabricated by plasma electrolytic carburizing (PEC) in glycerol solution at 380 V with 3 min treatment. The discharge process was characterized using optical emission spectroscopy (OES), and the electron temperature in plasma envelope was determined. Meanwhile, diffusion coefficient of carbon was calculated on the basis of carbon concentration profile. The tribological property of carburized steel under dry sliding against ZrO{sub 2} ball was measured by a ball-disc friction and wear tester. The corrosion behaviors were evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). It was found that the carburized layer mainly contained α-Fe and Fe{sub 3}C phases with maximum hardness of 620 HV. The PEC treatment significantly decreased the friction coefficient from 0.4 to 0.1. The wear rate of PEC treated steel was about 5.86 × 10{sup −6} mm{sup 3}/N·m, which was less than 1/4 of T8 steel substrate. After PEC treatment, the wear and corrosion resistance of T8 steel were improved. Particularly, the pitting corrosion of steel substrate was obviously suppressed. - Highlights: • Electron temperature in plasma electrolytic carburizing process is determined. • Diffusion coefficient of carbon in PEC is higher than conventional carburizing. • Wear and corrosion resistance of T8 steel are both improved after PEC treatment. • Pitting corrosion of steel substrate is obviously suppressed by PEC treatment.

  13. Investigation of Corrosion Behaviour of Aluminium Alloy Subjected to Laser Shock Peening without a Protective Coating

    Directory of Open Access Journals (Sweden)

    U. Trdan

    2015-01-01

    Full Text Available The effect of shock waves and strain hardening of laser shock peening without protective coating (LSPwC on alloy AA 6082-T651 was investigated. Analysis of residual stresses confirmed high compression in the near surface layer due to the ultrahigh plastic strains and strain rates induced by multiple laser shock waves. Corrosion tests in a chloride environment were carried out to determine resistance to localised attack, which was also verified on SEM/EDS. OCP transients confirmed an improved condition, that is, a more positive and stable potential after LSPwC treatment. Moreover, polarisation resistance of the LSPwC treated specimen was by a factor of 25 higher compared to the untreated specimen. Analysis of voltammograms confirmed an improved enhanced region of passivity and significantly smaller anodic current density of the LSPwC specimen compared to the untreated one. Through SEM, reduction of pitting attack at the LSPwC specimen surface was confirmed, despite its increased roughness.

  14. Corrosion Behaviour of a Silane Protective Coating for NdFeB Magnets in Dentistry

    Directory of Open Access Journals (Sweden)

    Luigi Calabrese

    2015-01-01

    Full Text Available The corrosion behavior of coated and uncoated Ni/Cu/Ni rare earth magnets was assessed at increasing steps with a multilayering silanization procedure. Magnets’ durability was analyzed in Fusayama synthetic saliva solution in order to evaluate their application in dental field. Corrosion performance was evaluated by using polarization and electrochemical impedance spectroscopy in synthetic saliva solution up to 72 hours of continuous immersion. The results show that the addition of silane layers significantly improved anticorrosion properties. The coating and aging effects, in synthetic saliva solution, on magnetic field were evaluated by means of cyclic force-displacement curves.

  15. Study of the Effect of Sol pH and Nanoclay Incorporation on the Corrosion Protection Performance of a Silane Sol-Gel Coating

    Directory of Open Access Journals (Sweden)

    Najmeh Asadi

    2014-06-01

    Full Text Available This work is aimed to evaluate the role of nanoclay in the protective performance of an eco-friendly silane sol-gel layer applied on mild steel substrate in 0.1M sodium chloride solution. At the first step, the effect of pH of the silane solution, consisting of a mixture of γ-glycidoxypropiltrimethoxysilane and methyltriethoxysilane and tetraethoxysilane, on the coating performance was evaluated through electrochemical noise measurements. The values of characteristic charge as a parameter extracted from shot noise theory revealed that the sol pH determining the rate of hydrolysis can play an important role in the corrosion protection behavior of silane coatings. Then, the influence of clay nanoparticles on the corrosion protective performance of the hybrid silane film was studied through taking advantage of electrochemical techniques, including electrochemical impedance spectroscopy and polarization curves, as well as surface analysis methods. The obtained electrochemical data including the values of charge transfer resistance, coating resistance, low frequency impedance and corrosion current density showed that the silane sol gel film in the presence of clay nanoparticles can present an improved corrosion protection. The behavior was connected to an enhancement in the coating barrier properties. Moreover, FESEM and water contact angle confirmed the higher reticulation in case of the coating incorporating nanoclay.

  16. Hydrothermal synthesis and corrosion behavior of the protective coating on Mg-2Zn-Mn-Ca-Ce alloy

    Directory of Open Access Journals (Sweden)

    Dan Song

    2016-12-01

    Full Text Available Protective coatings were synthesized on the Mg-2Zn-Mn-Ca-Ce Mg alloy through the hydrothermal method with de-ionized water as the reagent. The coatings were composed of Mg hydroxide, generally uniform and compact. Hydrogen evolution tests and electrochemical tests in the Hanks’ solution demonstrated that the Mg(OH2 coatings effectively decreased the bio-degradation rate of the Mg alloy substrate. Microstructure observation showed that the coating formation on the secondary phases was more difficult than that on the α-Mg matrix, which led to micro cracks and pores on the secondary phases after drying. Over synthesizing time, the coating layer on secondary phases gradually becomes more compact and uniform. Meanwhile, owing to the thicker and more compact coatings, the corrosion resistance and protective efficiency were significantly improved with longer synthesizing time as well.

  17. Protection of 2024-T3 aluminium alloy by corrosion resistant phytic acid conversion coating

    Science.gov (United States)

    Shi, Hongwei; Han, En-Hou; Liu, Fuchun; Kallip, Silvar

    2013-09-01

    The corrosion protection properties of environmentally friendly phytic acid conversion coatings were studied on 2024-T3 aluminium alloy. The films were prepared under acidic conditions with various pH values and characterised by SEM, EDS, ATR-FTIR and electrochemical techniques. The results indicate that the conversion coatings obtained by immersing the alloy in phytic acid solutions at pH from 3 to 5.5 provide excellent corrosion resistance. ATR-FTIR confirms that the film is formed by deposition of reaction products between Al3+ and phosphate groups in phytic acid molecules. The conformation models of the deposition film are proposed.

  18. 硫磺回收装置的腐蚀及防护措施%Corrosion of Equipment in Sulfur Recovery of Coke Oven Gas Unit and Protection

    Institute of Scientific and Technical Information of China (English)

    冯江华; 李慧敏; 张继明; 张方

    2012-01-01

    Analysis of coke oven gas desulfurization production process with vacuum carbonate method,corrosion and its mechanism in the form of important devices,morphology and characteristics of metal sulfide corrosion layers,and made against the different forms of corrosion problems of the improved process control,equipment,appropriate protection measures.%分析了焦炉煤气采用真空碳酸盐法脱硫的生产过程中,重要装置存在的腐蚀形式及其发生的机理,金属硫化腐蚀层的形态与特征,并针对不同形态的腐蚀问题提出了工艺控制、设备改进等相应的防护措施。

  19. Corrosion protection of AZ31 magnesium alloy treated with La3+ modified 3-methacryloxypropyltrimethoxysilane conversion film

    Institute of Scientific and Technical Information of China (English)

    乔英杰; 李文鹏; 王桂香; 张晓红

    2015-01-01

    This study demonstrated the influence of addition concentration of La3+ on the anti-corrosion behavior of a 3-methacry-loxypropyltrimethoxysilane (MPS) film formed on AZ31 magnesium alloy. The morphology and surface chemistry of the samples were evaluated through scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR), respectively. The corrosion resistance of the pre-treated AZ31 magnesium alloy was studied during immersion in 0.1 mol/L NaCl solution, using poten-tiodynamic polarization curves and electrochemical impedance spectra (EIS). In comparison to MPS film, the low concentration of La3+ ion modified silane layer exhibited a better anti-corrosion performance, nevertheless, the high concentration of La3+ ion modified was worse. Results showed that the preferable addition concentration of La3+ ion in the silane film was 5×10–4 mol/L in this experi-ment.

  20. Characterization of a “Smart” Hybrid Varnish Electrospun Nylon Benzotriazole Copper Corrosion Protection Coating

    Directory of Open Access Journals (Sweden)

    C. Menchaca

    2012-01-01

    Full Text Available This work presents the electrochemical evaluation of a proposed copper corrosion protection hybrid coating acting as a smart corrosion protection system. This consists of an alkyd varnish, painted over electrospun nylon fibers acting as a secondary diffusion barrier and also as a benzotriazole (BTAH inhibitor nanocontainer. Submicron diameter electrospun nylon 6-6 fiber nanocontainers were prepared from a polymeric solution containing BTAH at different concentrations, and Cu samples were coated with the electrospun fibers and painted over with an alkyd varnish by the drop method. Functional groups in fibers were determined through FTIR spectroscopy. Optical and SEM microscopies were used to characterize the nanocontainer fibers. Samples were evaluated using electrochemical impedance and noise, during six weeks of immersion, in a chloride-ammonium sulfate solution. Excellent response was obtained for the smart inhibitor coating system. For long periods of immersion good corrosion protection performance was observed. The results presented demonstrate the good barrier properties of the hybrid coating, obstructing the diffusion of aggressive species, through the electrospun structure. Furthermore the nanocontainer functionality to store and liberate the corrosion inhibitor, only when it is needed, was also proved.

  1. Nanotechnology based surface treatments for corrosion protection and deposit control of power plant equipment. Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-05-15

    Nanotechnology can provide possibilities for obtaining new valuable information regarding performance and corrosion protection in power plants. In general the desired performance of the contact surfaces is an easy-to-release effect. This is in order to prolong the time interval between cleaning periods or make the cleaning procedures easier and less expensive. Corrosion protection is also desired in order to extend the life time of various parts in the power plants and thus optimize the energy output and overall efficiency of the plant. Functional sol-gel coating based on nanotechnology is tested in a variety of conditions. Applications of functional sol-gel coatings were performed in the condenser and on seven air preheaters at Fynsvaerket, Odense, with corrosion protection as the main issue. Coatings with easy-to-clean effects were tested in the Flue Gas Desulphurization plant at Nordjyllandsvaerket, Aalborg, with the aim of reducing gipsum deposit. Thermo stabilized coatings were tested on tube bundles between in the passage from the 1st to 2end pass and on the wall between 1st and 2end pass at Amagervaerket, Copenhagen, and in the boiler at Haderslev CHP plant. The objective of this test were reducing deposits and increasing corrosion protection. The tested coatings were commercial available coatings and coatings developed in this project. Visual inspections have been performed of all applications except at Nordjyllandsvaerket. Corrosion assessment has been done at DTU - Mechanical Engineering. The results range from no difference between coated and uncoated areas to some improvements. At Amagervaerket the visual assessment showed in general a positive effect with a sol-gel hybrid system and a commercial system regarding removal of deposits. The visual assessment of the air preheaters at Fynsvaerket indicates reduced deposits on a sol-gel nanocomposite coated air preheater compared to an uncoated air preheater. (Author)

  2. Enhancement of corrosion protection effect in mechanochemically synthesized Polyaniline/MMT clay nanocomposites

    Directory of Open Access Journals (Sweden)

    N. Kalaivasan

    2017-02-01

    Full Text Available Nanocomposite material that consists of DBSA (dodecylbenzensulfonic acid doped polyaniline (PANI was prepared by solvent free mechanochemical intercalation method. Organic aniline monomer was first intercalated into the interlayer regions of Na-MMT (sodium montmorillonite clay hosts and followed by one-step oxidative polymerization. The as synthesized polyaniline clay nanocomposites were treated with DBSA to get PANI-DBSA clay nanocomposites. PANI-DBSA clay nanocomposites in the form of coatings at different concentrations of DBSA on C45 steel were found much superior in corrosion protection over those of conventional polyaniline, based on the series of electrochemical measurement of corrosion potential, polarization resistance and corrosion current in 3.5% aqueous NaCl electrolyte. UV–visible spectroscopy, FT-IR and SEM studies confirm the formation of intercalated polyaniline clay nanocomposites inside the clay nanolayers.

  3. Cerium oxide as conversion coating for the corrosion protection of aluminum

    Directory of Open Access Journals (Sweden)

    JELENA GULICOVSKI

    2013-11-01

    Full Text Available CeO2 coatings were formed on the aluminum after Al surface preparation, by dripping the ceria sol, previously prepared by forced hydrolysis of Ce(NO34. The anticorrosive properties of ceria coatings were investigated by the electrochemical impedance spectroscopy (EIS during the exposure to 0.03 % NaCl. The morphology of the coatings was examined by the scanning electron microscopy (SEM. EIS data indicated considerably larger corrosion resistance of CeO2-coated aluminum than for bare Al. The corrosion processes on Al below CeO2 coating are subjected to more pronounced diffusion limitations in comparison to the processes below passive aluminum oxide film, as the consequence of the formation of highly compact protective coating. The results show that the deposition of ceria coatings is an effective way to improve corrosion resistance for aluminum.

  4. Corrosion resistance of biodegradable polymeric layer-by-layer coatings on magnesium alloy AZ31

    Science.gov (United States)

    Cui, Lan-Yue; Zeng, Rong-Chang; Zhu, Xiao-Xiao; Pang, Ting-Ting; Li, Shuo-Qi; Zhang, Fen

    2016-06-01

    Biocompatible polyelectrolyte multilayers (PEMs) and polysiloxane hybrid coatings were prepared to improve the corrosion resistance of biodegradable Mg alloy AZ31. The PEMs, which contained alternating poly(sodium 4-styrenesulfonate) (PSS) and poly(allylamine hydrochloride) (PAH), were first self-assembled on the surface of the AZ31 alloy substrate via electrostatic interactions, designated as (PAH/PSS)5/AZ31. Then, the (PAH/PSS)5/AZ31 samples were dipped into a methyltrimethoxysilane (MTMS) solution to fabricate the PMTMS films, designated as PMTMS/(PAH/PSS)5/AZ31. The surface morphologies, microstructures and chemical compositions of the films were investigated by FE-SEM, FTIR, XRD and XPS. Potentiodynamic polarization, electrochemical impedance spectroscopy and hydrogen evolution measurements demonstrated that the PMTMS/(PAH/PSS)5/AZ31 composite film significantly enhanced the corrosion resistance of the AZ31 alloy in Hank's balanced salt solution (HBSS). The PAH and PSS films effectively improved the deposition of Ca-P compounds including Ca3(PO4)2 and hydroxyapatite (HA). Moreover, the corrosion mechanism of the composite coating was discussed. These coatings could be an alternative candidate coating for biodegradable Mg alloys.

  5. Thermal Spray Coatings for High-Temperature Corrosion Protection in Biomass Co-Fired Boilers

    Science.gov (United States)

    Oksa, M.; Metsäjoki, J.; Kärki, J.

    2015-01-01

    There are over 1000 biomass boilers and about 500 plants using waste as fuel in Europe, and the numbers are increasing. Many of them encounter serious problems with high-temperature corrosion due to detrimental elements such as chlorides, alkali metals, and heavy metals. By HVOF spraying, it is possible to produce very dense and well-adhered coatings, which can be applied for corrosion protection of heat exchanger surfaces in biomass and waste-to-energy power plant boilers. Four HVOF coatings and one arc sprayed coating were exposed to actual biomass co-fired boiler conditions in superheater area with a probe measurement installation for 5900 h at 550 and 750 °C. The coating materials were Ni-Cr, IN625, Fe-Cr-W-Nb-Mo, and Ni-Cr-Ti. CJS and DJ Hybrid spray guns were used for HVOF spraying to compare the corrosion resistance of Ni-Cr coating structures. Reference materials were ferritic steel T92 and nickel super alloy A263. The circulating fluidized bed boiler burnt a mixture of wood, peat and coal. The coatings showed excellent corrosion resistance at 550 °C compared to the ferritic steel. At higher temperature, NiCr sprayed with CJS had the best corrosion resistance. IN625 was consumed almost completely during the exposure at 750 °C.

  6. Peptide-based biocoatings for corrosion protection of stainless steel biomaterial in a chloride solution.

    Science.gov (United States)

    Muruve, Noah G G; Cheng, Y Frank; Feng, Yuanchao; Liu, Tao; Muruve, Daniel A; Hassett, Daniel J; Irvin, Randall T

    2016-11-01

    In this work, PEGylated D-amino acid K122-4 peptide (D-K122-4-PEG), derived from the type IV pilin of Pseudomonas aeruginosa, coated on 304 stainless steel was investigated for its corrosion resistant properties in a sodium chloride solution by various electrochemical measurements, surface characterization and molecular dynamics simulation. As a comparison, stainless steel electrodes coated with non-PEGylated D-amino acid retroinverso peptide (RI-K122-4) and D-amino acid K122-4 peptide (D-K122-4) were used as control variables during electrochemical tests. It was found that the D-K122-4-PEG coating is able to protect the stainless steel from corrosion in the solution. The RI-K122-4 coating shows corrosion resistant property and should be investigated further, while the D-K122-4 peptide coating, in contrast, shows little to no effect on corrosion. The morphological characterizations support the corrosion resistance of D-K122-4-PEG on stainless steel. The adsorption of D-K122-4 molecules occurs preferentially on Fe2O3, rather than Cr2O3, present on the stainless steel surface. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Institute of Scientific and Technical Information of China (English)

    Jiang Xu; Xishan Xie; Zhong Xu; Wenjin Liu

    2004-01-01

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

  8. Investigation of the inner corrosion layer formed in pulse electrodeposition coating on Mg-Sr alloy and corresponding degradation behavior.

    Science.gov (United States)

    Shangguan, Yongming; Wan, Peng; Tan, Lili; Fan, Xinmin; Qin, Ling; Yang, Ke

    2016-11-01

    Magnesium-based metals are considered as promising biodegradable orthopedic implant materials due to their potentials of enhancing bone healing and reconstruction, and in vivo absorbable characteristic without second operation for removal. However, the rapid corrosion has limited their clinical applications. Ca-P coating by electrodeposition has been supposed to be effective to control the degradation rate and enhance the bioactivity. In this work, a brushite coating was fabricated on the Mg-Sr alloy by pulse electrodeposition (PED) to evaluate its efficacy for orthopedic application. Interestingly, an inner corrosion layer was observed between the PED coating and the alloy substrate. Meanwhile the results of in vitro immersion and electrochemical tests showed that the corrosion resistance of the coated alloy was undermined in comparison with the uncoated alloy. It was deduced that the existence of this corrosion layer was attributed to the worse corrosion performance of the alloy. The mechanism on formation of the inner corrosion layer and its influence on consequent degradation were analyzed. It can be concluded that the electrodeposition coating should be not suitable for those magnesium alloys with poor corrosion resistance such as the Mg-Sr alloy. More importantly, it should be noted that the process of coating formation combined with the nature of substrate alloy is important to evaluate the efficacy of coating for biodegradable Mg-based implants application.

  9. Evaluation of Corrosion Protection Methods for Aluminum Metal Matrix Composites

    Science.gov (United States)

    1992-08-01

    and hot water sealed MMCs 75 5.9 Calculated Barrier Layer Thickness for AA6061, A356 and3 2009/20% SiCr 81 5.10 Comparison of Exposure test results...anodized and hot water sealed 2009/20% SiCr after exposure to 0.5 N NaCI for 2 hrs, 17 days and 28 days. 224 I II Ii I * xv Figure Page 5.48 Bode plots...28 1 20.o SiCr 28 3 6061/20% AI,0 3 28 7I resembles that for hot water scaling with the porous layer capacitance and pore impedance visible in the

  10. Hybrid nanostructured coatings for corrosion protection of base metals: a sustainability perspective

    Science.gov (United States)

    Dennis, Robert V.; Patil, Vikas; Andrews, Justin L.; Aldinger, Jeffrey P.; Yadav, Ganapati D.; Banerjee, Sarbajit

    2015-03-01

    In this topical review article, we attempt to capture recent advances in the development of sustainable hybrid nanocomposite coatings for the corrosion inhibition of structural metals. Spurred primarily by the urgent imperative of replacing hexavalent chromium but also driven by concerns regarding the environmental impact of organic solvents, materials criticality considerations, the need to maintain structural integrity and function under extreme environments, and a renewed impetus towards lightweighting, the design of new coating concepts has seen an explosion of activity. We discuss varying modes of corrosion inhibition and the drive towards multicomponent nanostructured coatings that synergistically unite multiple modes of corrosion inhibition within a single coating system. Nanocomposite coatings in which nanoparticles of one phase are dispersed within a continuous phase, usually a polymeric matrix, provide a modular design approach to multifunctional coatings provided fundamental challenges such as dispersion and compatibility can be resolved. By dint of their high surface-to-volume ratios, the incorporation of nanoparticles profoundly modifies the adjacent polymeric matrix, giving rise to an ‘interphase’ region with modified properties, at relatively low filler loadings. The implications of incorporating metallic, porous metal oxide, and carbon nanomaterials (graphene and carbon nanotubes) within polymeric matrices are explored with an emphasis on active corrosion inhibition. The availability of high-quality nanoparticles that are either electroactive (e.g., metals, graphene, carbon nanotubes, etc.) or are capable of serving as reservoirs for active corrosion inhibitors (e.g., porous silicon oxide, layered double hydroxides, halloysite) provides unprecedented functionality and opportunities for multifunctional coatings. The review emphasizes mechanistic considerations where these have been elucidated with a view towards developing systematic design

  11. An electrochemical evaluation of new materials and methods for corrosion protection

    Science.gov (United States)

    Kus, Esra

    An electrochemical evaluation of various electrode/electrolyte systems was performed by means of electrochemical impedance spectroscopy (EIS) and other techniques. Each chapter in this thesis presents an individual project with a specific objective which serves an ultimate goal of finding better materials and methods of corrosion protection. An overview of new environmentally friendly and cost effective materials and corrosion protection methods is given in Chapter 1. The protective properties of non-toxic, environmentally friendly polymer coatings, which were developed in the purpose of minimizing biofouling and providing corrosion protection on steel, were investigated and discussed in Chapter 2. The corrosion resistance of steel panels coated with crosslinked siloxanes was evaluated using EIS. Differences in protective properties of the coatings were observed due to differences in the degree of fluorination, the way the films were cured and also the degree of crosslinking. In Chapter 3, a comparison of the corrosion behavior of nanocrystalline (NC) Al 5083 with that of the conventional alloy was made in order to determine what differences if any could be attributed to the NC microstructure. Pit growth rates decreased with time for both materials based on the analysis of the impedance spectra as a function of time. NC samples were resistant to intergranular corrosion whereas conventional Al 5083 was not. The concept of the bacterial battery is presented in Chapter 4. A galvanic cell with Cu and Al 2024 and an electrolyte containing Shewanella oneidensis MR-1 in a growth medium was prepared. A control cell, which did not contain the bacteria, was also tested. For the cell with MR-1 the maximum power values increased continuously with time, whereas in the control cell the maximum power output was obtained in the first day of exposure. The objective of the study presented in Chapter 5 was to examine the interaction of MR-1 with different metal surfaces in order to

  12. Corrosion Potential Profile Simulation in a Tube under Cathodic Protection

    Directory of Open Access Journals (Sweden)

    Mauricio Ohanian

    2014-01-01

    Full Text Available The potential distribution in tubes of a heat exchanger is simulated when applying cathodic polarization to its extremes. The comparison of two methods to achieve this goal is presented: a numeric solution based on boundary elements carried out with the commercial software Beasy-GID and a semianalytical method developed by the authors. The mathematical model, the simplifications considered, and the problem solving are shown. Since both approaches use polarization curves as a boundary condition, experimental polarization curves (voltage versus current density were determined in the laboratory under flow conditions and cylindrical cell geometry. The results obtained suggest the impossibility of extending the protection along the whole tube length; therefore, other protection methods are considered.

  13. Corrosion Protection Properties of PPy-ND Composite Coating: Sonoelectrochemical Synthesis and Design of Experiment

    Science.gov (United States)

    Ashassi-Sorkhabi, H.; Bagheri, R.; Rezaei-Moghadam, B.

    2016-02-01

    In this research, the nanocomposite coatings comprising the polypyrrole-nanodiamond, PPy-ND, on St-12 steel electrodes were electro-synthesized using in situ polymerization process under ultrasonic irradiation. The corrosion protection performance and morphology characterization of prepared coatings were investigated by electrochemical methods and scanning electron microscopy, SEM, respectively. Also, the experimental design was employed to determine the best values considering the effective parameters such as the concentration of nanoparticles, the applied current density and synthesis time to achieve the most protective films. A response surface methodology, RSM, involving a central composite design, CCD, was applied to the modeling and optimization of the PPy-ND nanocomposite deposition. Pareto graphic analysis of the parameters indicated that the applied current density and some of the interactions were effective on the response. The electrochemical results proved that the embedment of diamond nanoparticle, DNP, improves the corrosion resistance of PPy coatings significantly. Therefore, desirable correlation exists between predicted data and experimental results.

  14. Modeling of Multi-Layered Protection Systems for Chloride Penetration in Concrete Bridge Decks

    Science.gov (United States)

    Harajli, Ali A.

    Modeling of Multi-Layered Protection Systems for Chloride Penetration in Concrete Bridge Decks. This paper covers the development of a new methodology for predicting the chloride concentration and corrosion initiation times for a multi-layer protection overlay system. The first topic will be presenting an innovative method to predict the chloride concentrations using different diffusion coefficients for each protective layer. The new method covers the cases where the applied surface chloride concentrations are either a constant or linear functions with time. The second topic will implement the results from field data about the chloride variations due to the presence of applied topical layers for comparison with the theoretical models. This section will also apply damage factors that are time-dependent to simulate external factors such as traffic loading or vibrations. The third topic will investigate the sensitivity of the single and multi-layer systems due to diffusivity parameter changes. The fourth topic will analyze the random variation of the diffusivity values to predict the mean and standard deviation of chloride concentrations. The diffusivity values are selected from published values by NIST and are based on certain water cement (w/c) ratios.

  15. Structural and corrosion protection properties of electrochemically deposited nano-sized Zn–Ni alloy coatings

    Energy Technology Data Exchange (ETDEWEB)

    Tozar, A., E-mail: tozarali@gmail.com; Karahan, İ.H.

    2014-11-01

    Highlights: • Nano-sized, compact and bright deposits were obtained galvanostatically. • Deposition of zinc–nickel alloys has been materialized in domination of zinc-rich ∂-(Ni{sub 3}Zn{sub 22}) and γ-(Ni{sub 5}Zn{sub 22}) phases. • Sodium citrate (Na{sub 3}C{sub 6}H{sub 5}O{sub 7}) has been used together with boric acid (H{sub 3}BO{sub 3}) for inhibition of instantaneous deposition of zinc and accordingly increasing the relative amount of nickel. • Corrosion protection performances of the deposits were increased with increasing deposition current density and nickel amount. • Crystal defects have been increased with decreasing crystallite size. - Abstract: Zn–Ni alloy coatings were fabricated galvanostatically by applying varied current densities from 10 to 30 mA cm{sup −2}. Surface morphology of the coatings was examined with SEM. Crystal structure of the coatings was studied with X-ray diffraction spectroscopy (XRD). Compositions of the coatings were determined by atomic absorption spectroscopy (AAS). Corrosion protection properties studied using open circuit potential (OCP) measurements, potentiodynamic polarization measurements (Tafel), electrochemical impedance spectroscopy (EIS). Deposited alloy coatings were compact and nano-sized. Crystallite sizes of the coatings were varying from 26 nm to 36 nm. Nickel content of the samples were increased by increasing current densities and varied from 6.7 to 18.9 wt.%. Best corrosion protection performance was seen on the sample obtained at 30 mA cm{sup −2}. Our results are considerably encouraging for protection of mild steel against corrosion by obtained Zn–Ni alloys.

  16. Corrosion resistant coating

    Science.gov (United States)

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

    1997-01-01

    A method of protecting a metal substrate from corrosion including coating a metal substrate of, e.g., steel, iron or aluminum, with a conductive polymer layer of, e.g., polyaniline, coating upon said metal substrate, and coating the conductive polymer-coated metal substrate with a layer of a topcoat upon the conductive polymer coating layer, is provided, together with the resultant coated article from said method.

  17. Effects of surface modification with hydroxyl terminated polydimethylsiloxane on the corrosion protection of polyurethane coating

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Jae Hong; Shon, Min Young [Pukyong National University, Busan (Korea, Republic of)

    2014-10-15

    Polyurethane coating was designed to give a hydrophobic property on its surface by modifying it with hydroxyl terminated polydimethylsiloxane and then effects of surface hydrophobic tendency, water transport behavior and hence corrosion protectiveness of the modified polyurethane coating were examined using FT-IR/ATR spectroscopy, contact angle measurement and electrochemical impedance test. As results, the surface of polyurethane coating was changed from hydrophilic to hydrophobic property due primarily to a phase separation tendency between polyurethane and modifier by the modification. The phase separation tendency is more appreciable when modified by polydimethylsiloxane with higher content. Water transport behavior of the modified polyurethane coating decreased more in that with higher hydrophobic surface property. The decrease in the impedance modulus ⅠZⅠ at low frequency region in immersion test for polyurethane coatings was associated with the water transport behavior and surface hydrophobic properties of modified polyurethane coatings. The corrosion protectiveness of the modified polyurethane coated carbon steel generally increased with an increase in the modifier content, confirming that corrosion protectiveness of the modified polyurethane coating is well agreed with its water transport behavior.

  18. Microbiologically Induced Corrosion of Concrete and Protective Coatings in Gravity Sewers

    Institute of Scientific and Technical Information of China (English)

    Marjorie Valix; Diyana Zamri; Hiro Mineyama; Wai Hung Cheung; Jeffrey Shi; Heri Bustamante

    2012-01-01

    Microbiologically induced corrosion of concrete (MICC) and its protective coatings has a high eco-nomic impact on sewer maintenance and rehabilitation. A better understanding of the micro-organisms and the bio- genie acids that are generated in the sewer is essential in controlling the corrosion of concrete pipes and protective coatings. The role of succession of micro-organisms growth in the corrosion of concrete and protective coatings was evaluated in this study. Examination of various sewer pipe materials exhibiting various extents of degradation, including concrete, cement based and epoxy based coating revealed the presence of both organic and biogenic sulphuric acids. This reflects the activity of fungi and the thiobacilli strains. Organism growth and metabolism were strongly related to the substrate pH. Fungi were found to grow and metabolise organic acids at pH from 2.0-8.0. Whilst the thiobacilli strains grew and generated sulohuric acids at oH below 3.0. The successive growth of the organisms provides an impgrtant bearing in deyeloping improved strateegies.to better manage sewers.

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

    Science.gov (United States)

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

    2015-05-01

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

  20. Hybrid organic-inorganic coatings including nanocontainers for corrosion protection of magnesium alloy ZK30

    Energy Technology Data Exchange (ETDEWEB)

    Kartsonakis, I. A., E-mail: ikartsonakis@ims.demokritos.gr [IAMPPNM, NCSR ' DEMOKRITOS' , Sol-Gel Laboratory (Greece); Koumoulos, E. P.; Charitidis, C. A., E-mail: charitidis@chemeng.ntua.gr [School of Chemical Engineering NTUA (Greece); Kordas, G. [IAMPPNM, NCSR ' DEMOKRITOS' , Sol-Gel Laboratory (Greece)

    2013-08-15

    This study is focused on the fabrication, characterization, and application of corrosion protective coatings to magnesium alloy ZK30. Hybrid organic-inorganic coatings were synthesized using organic-modified silicates together with resins based on bisphenol A diglycidyl ether. Cerium molybdate nanocontainers (ncs) with diameter 100 {+-} 20 nm were loaded with corrosion inhibitor 2-mercaptobenzothiazole and incorporated into the coatings in order to improve their anticorrosion properties. The coatings were investigated for their anticorrosion and nanomechanical properties. The morphology of the coatings was examined by scanning electron microscopy. The composition was estimated by energy-dispersive X-ray analysis. The mechanical integrity of the coatings was studied through nanoindentation and nanoscratch techniques. Scanning probe microscope imaging of the coatings revealed that the addition of ncs creates surface incongruity; however, the hardness to modulus ratio revealed significant strengthening of the coating with increase of ncs. Studies on their corrosion behavior in 0.5 M sodium chloride solutions at room temperature were made using electrochemical impedance spectroscopy. Artificial defects were formatted on the surface of the films in order for possible self-healing effects to be evaluated. The results showed that the coated magnesium alloys exhibited only capacitive response after exposure to corrosive environment for 16 months. This behavior denotes that the coatings have enhanced barrier properties and act as an insulator. Finally, the scratched coatings revealed a partial recovery due to the increase of charge-transfer resistance as the immersion time elapsed.

  1. Hybrid organic-inorganic coatings including nanocontainers for corrosion protection of magnesium alloy ZK30

    Science.gov (United States)

    Kartsonakis, I. A.; Koumoulos, E. P.; Charitidis, C. A.; Kordas, G.

    2013-08-01

    This study is focused on the fabrication, characterization, and application of corrosion protective coatings to magnesium alloy ZK30. Hybrid organic-inorganic coatings were synthesized using organic-modified silicates together with resins based on bisphenol A diglycidyl ether. Cerium molybdate nanocontainers (ncs) with diameter 100 ± 20 nm were loaded with corrosion inhibitor 2-mercaptobenzothiazole and incorporated into the coatings in order to improve their anticorrosion properties. The coatings were investigated for their anticorrosion and nanomechanical properties. The morphology of the coatings was examined by scanning electron microscopy. The composition was estimated by energy-dispersive X-ray analysis. The mechanical integrity of the coatings was studied through nanoindentation and nanoscratch techniques. Scanning probe microscope imaging of the coatings revealed that the addition of ncs creates surface incongruity; however, the hardness to modulus ratio revealed significant strengthening of the coating with increase of ncs. Studies on their corrosion behavior in 0.5 M sodium chloride solutions at room temperature were made using electrochemical impedance spectroscopy. Artificial defects were formatted on the surface of the films in order for possible self-healing effects to be evaluated. The results showed that the coated magnesium alloys exhibited only capacitive response after exposure to corrosive environment for 16 months. This behavior denotes that the coatings have enhanced barrier properties and act as an insulator. Finally, the scratched coatings revealed a partial recovery due to the increase of charge-transfer resistance as the immersion time elapsed.

  2. Improvement on the corrosion protection of conductive polymers in PEMFC environments by adhesives

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Rodriguez, J.G.; Lucio-Garcia, M.A.; Nicho, M.E.; Cruz-Silva, R. [UAEM-CIICAP, Av. Universidad 1001, Col. Chamilpa, 62209-Cuernavaca, Morelos (Mexico); Casales, M. [Universidad Nacional Autonoma de Mexico, Instituto de Ciencicas Fisicas, Av. Universidad s/n, Col. Chamilpa, 62210-Cuernavaca, Morelos (Mexico); Valenzuela, E. [Universidad Politecnica de Chiapas, Cuerpo Academico de Energia y Sustentabilidad Eduardo J. Selvas S/N, Col. Magisterial, Tuxtla Gutierrez, Chiapas (Mexico)

    2007-05-25

    The corrosion protection of polypyrrol (PPY) and polyaniline (PANI) coatings electrochemically deposited with and without polyvinyl alcohol (PVA) as adhesive onto 304 type stainless steel has been evaluated using electrochemical techniques. Environment included 0.5 M H{sub 2}SO{sub 4} at 60 C whereas employed techniques included potentiodynamic polarization curves (PC), linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS) measurements. Results showed that the free corrosion potential, of the substrate, E{sub corr}, was made more noble up to 500 mV with the polymeric coatings. The corrosion rate was lowered by using the polymers, but with the addition of PVA, it was decreased further, one order of magnitude for PPY and up to three orders of magnitude for PANI. Impedance spectra showed that the corrosion mechanism is under a Warburgh-type diffusional process of the electrolyte throughout the coating, and that the uptake of the environment causes the eventual failure of the coating corroding the substrate. (author)

  3. Synthesis and corrosion protection properties of poly(o-phenylenediamine) nanofibers.

    Science.gov (United States)

    Muthirulan, P; Kannan, N; Meenakshisundaram, M

    2013-07-01

    The present study shows a novel method for the synthesis of uniformly-shaped poly(othophenylediamine) (PoPD) nanofibers by chemical oxidative polymerization method for application towards smart corrosion resistance coatings. Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) studies confirm morphology of PoPD with three dimensional (3D) networked dendritic superstructures having average diameter of 50-70 nm and several hundred meters of length. UV-vis and FTIR spectral results shows the formation of PoPD nanofibers containing phenazine ring ladder-structure with benzenoid and quinoid imine units. Thermogravimetric analyses (TGA) of PoPD nanofibers possess good thermal stability. The anti-corrosion behavior of PoPD nanofibers on 316L SS was investigated in 3.5% NaCl solution using potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) measurements. The PoPD coated 316L SS exhibits higher corrosion potential when compared to uncoated specimen. EIS studies, clearly ascertain that PoPD nanofiber coatings exhibits excellent potential barrier to protect the 316L SS against corrosion in 3.5% NaCl.

  4. Synthesis and corrosion protection properties of poly(o-phenylenediamine nanofibers

    Directory of Open Access Journals (Sweden)

    P. Muthirulan

    2013-07-01

    Full Text Available The present study shows a novel method for the synthesis of uniformly-shaped poly(othophenylediamine (PoPD nanofibers by chemical oxidative polymerization method for application towards smart corrosion resistance coatings. Transmission Electron Microscopy (TEM and Scanning Electron Microscopy (SEM studies confirm morphology of PoPD with three dimensional (3D networked dendritic superstructures having average diameter of 50–70 nm and several hundred meters of length. UV–vis and FTIR spectral results shows the formation of PoPD nanofibers containing phenazine ring ladder-structure with benzenoid and quinoid imine units. Thermogravimetric analyses (TGA of PoPD nanofibers possess good thermal stability. The anti-corrosion behavior of PoPD nanofibers on 316L SS was investigated in 3.5% NaCl solution using potentiodynamic polarization and electrochemical impedance spectroscopic (EIS measurements. The PoPD coated 316L SS exhibits higher corrosion potential when compared to uncoated specimen. EIS studies, clearly ascertain that PoPD nanofiber coatings exhibits excellent potential barrier to protect the 316L SS against corrosion in 3.5% NaCl.

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

    Directory of Open Access Journals (Sweden)

    Jano, A.

    2012-11-01

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

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

    Science.gov (United States)

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

    2012-04-19

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

  7. Complete corrosion inhibition through graphene defect passivation.

    Science.gov (United States)

    Hsieh, Ya-Ping; Hofmann, Mario; Chang, Kai-Wen; Jhu, Jian Gang; Li, Yuan-Yao; Chen, Kuang Yao; Yang, Chang Chung; Chang, Wen-Sheng; Chen, Li-Chyong

    2014-01-28

    Graphene is expected to enable superior corrosion protection due to its impermeability and chemical inertness. Previous reports, however, demonstrate limited corrosion inhibition and even corrosion enhancement of graphene on metal surfaces. To enable the reliable and complete passivation, the origin of the low inhibition efficiency of graphene was investigated. Combining electrochemical and morphological characterization techniques, nanometer-sized structural defects in chemical vapor deposition grown graphene were found to be the cause for the limited passivation effect. Extremely fast mass transport on the order of meters per second both across and parallel to graphene layers results in an inhibition efficiency of only ∼50% for Cu covered with up to three graphene layers. Through selective passivation of the defects by atomic layer deposition (ALD) an enhanced corrosion protection of more than 99% was achieved, which compares favorably with commercial corrosion protection methods.

  8. Comparison of some corrosion-protective coatings for inner surfaces of tanks

    Energy Technology Data Exchange (ETDEWEB)

    Mityagin, V.A.; Vigant, G.T.; Zakharova, N.N.

    1995-07-01

    Zinc-filled, sprayed-zinc, epoxy, and vinyl chloride coatings were comparatively studied as applied to corrosion protection of inner surfaces and tanks for clarified petroleum products. Tests were carried out by cycles of temperature variation from 60{degrees}C to - 25{degrees}C, on steel plates in vapor, in fuel, and in electrolyte, simulating sub-product water. The coatings KhS-5132, KhS-717 (vinyl chloride) and BEP-68, EP-525, EP-0010 (epoxy) are of the highest protective properties, resistant to steaming and washing with aqueous solutions of synthetic detergents, and are compatible with clarified petroleum products.

  9. 电力铁塔角钢镀锌层在NaCl介质中的腐蚀行为研究%Corrosion Behavior of Angle Steel Galvanized Layer of Power Tower in NaCl Solution

    Institute of Scientific and Technical Information of China (English)

    邱妮; 姚强; 苗玉龙; 宗庆彬; 黎学明; 杨萍

    2011-01-01

    Corrosion behavior of angle steel galvanized layer was studied in NaCl solution by Tafel linear extrapolation and accelerated corrosion test. Morphologies and corrosion products after corrosion were characterized by SEM, XRD. The results show that the corrosion current density of angle steel galvanized layer becomes larger when the solution temperature and the concentration of NaCl increase. The products of accelerated corrosion test can provide protection against chloride corrosion, and the corrosion rate become smaller with the extension of test time. Oxygen concentration cell corrosion of zinc layer is a slow corrosion process that can not form "eclipse pits" easily, while the primary cell of Zn-Fe corrosion is a quick corrosion process that can result in superficial "eclipse pits" easily, and the white corrosion products are mainly Zn5(OH)8Cl2·H2O.%采用Tafel直线外推法、加速腐蚀试验,研究了角钢镀锌层在NaCl溶液中的腐蚀行为,利用SEM和XRD表征角钢镀锌层的腐蚀形貌及腐蚀产物.结果表明:随着NaCl溶液温度和浓度升高,角钢镀锌层腐蚀电流密度增大;加速腐蚀试验的产物可阻碍Cl-腐蚀,使得角钢锌层的腐蚀速率随试验时间的延长而减小;锌层的氧浓差腐蚀为慢腐蚀过程,不易形成“蚀坑”,而Zn-Fe构成原电池的腐蚀为快腐蚀,易造成表面的“蚀坑”;锌层白色腐蚀产物主要是Zn5(OH)8Cl2·H2O.

  10. Anti-corrosion layer prepared by plasma electrolytic carbonitriding on pure aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jie; Zhang, Yifan; Liu, Run; Wang, Bin; Hua, Ming [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Xue, Wenbin, E-mail: xuewb@bnu.edu.cn [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2015-08-30

    Highlights: • PEC/N can be applied to low melting point metal. • The spectroscopic characterization of plasma discharge is investigated. • Electron concentration and electron temperature are evaluated for PEC/N. • Phase composition of the carbonitrided layer is determined. • PEC/N improves the corrosion resistance of aluminum greatly. - Abstract: In this paper, plasma electrolytic carbonitriding (PEC/N) method was applied to pure aluminum for the first time. The spectroscopic characterization of plasma discharge during PEC/N process was analyzed and the electron temperature was calculated in terms of optical emission spectroscopy. The results showed the discharge plasma was in local thermal equilibrium (LTE) state. Electron concentration and electron temperature were about 6 × 10{sup 21} m{sup −3} and 4000 K, respectively. The carbonitrided layer contained Al{sub 4}C{sub 3}, AlN and Al{sub 7}C{sub 3}N{sub 3} phases. After PEC/N treatment, the corrosion resistance of pure aluminum was significantly improved, which was related to the formation of nitride phases. This work expands the application of plasma electrolysis technology on the surface modification of low melting point metal.

  11. Corrosion inhibition in sputter-deposited thin-film systems using an intermediary layer of palladium

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, D.J.

    1979-03-01

    Accelerated and long term corrosion data are presented for the Ti--Ag and Cr--Au thin film metallization systems deposited by sputter deposition. The Ti--Ag conductor system is used as an electrode for high intensity silicon solar cells, and it has been found that an intermediate layer of 1500 A of palladium greatly improves the environmental stability of the metallization. The Cr--Au system has been used as an electrical circuit pattern, and thin films of palladium (100--300 A) have been incorporated to improve storage, processing, and service stability. A 100 A palladium intermediary did not affect the etch patterning of the Cr--Au metallization. It is observed that the introduction of palladium modifies the anodic potential of the active metal producing a passive oxide when exposed to an electrolytic environment. It is proposed that this modified oxide, at exposed pinhole sites, is responsible for the increased corrosion resistance when palladium is present as an intermediate layer for either the Ti--Ag or Cr--Au metallization systems.

  12. Pre-oxidation and its effect on reducing high-temperature corrosion of superheater tubes during biomass firing

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Kvisgaard, M.; Montgomery, Melanie;

    2016-01-01

    Superheater tubes in biomass-fired power plants experience high corrosion rates due to condensation of corrosive alkali chloride-rich deposits. To explore the possibility of reducing the corrosion attack by the formation of an initial protective oxide layer, the corrosion resistance of pre-oxidis...

  13. Biofilms: strategies for metal corrosion inhibition employing microorganisms.

    Science.gov (United States)

    Zuo, Rongjun

    2007-10-01

    Corrosion causes dramatic economic loss. Currently widely used corrosion control strategies have disadvantages of being expensive, subject to environmental restrictions, and sometimes inefficient. Studies show that microbial corrosion inhibition is actually a common phenomenon. The present review summarizes recent progress in this novel strategy: corrosion control using beneficial bacteria biofilms. The possible mechanisms may involve: (1) removal of corrosive agents (such as oxygen) by bacterial physiological activities (e.g., aerobic respiration), (2) growth inhibition of corrosion-causing bacteria by antimicrobials generated within biofilms [e.g., sulfate-reducing bacteria (SRB) corrosion inhibition by gramicidin S-producing Bacillus brevis biofilm], (3) generation of protective layer by biofilms (e.g., Bacillus licheniformis biofilm produces on aluminum surface a sticky protective layer of gamma-polyglutamate). Successful utilization of this novel strategy relies on advances in study at the interface of corrosion engineering and biofilm biology.

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

    Science.gov (United States)

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

    2015-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Gergely, Andras, E-mail: andras.gergely@ttk.mta.hu [Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Pusztaszeri ut 59-67, 1025 Budapest (Hungary); Paszti, Zoltan; Hakkel, Orsolya; Drotar, Eszter [Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Pusztaszeri ut 59-67, 1025 Budapest (Hungary); Mihaly, Judith [Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Pusztaszeri ut 59-67, 1025 Budapest (Hungary); Kalman, Erika [Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Pusztaszeri ut 59-67, 1025 Budapest (Hungary)

    2012-11-01

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

  16. Transition of interface oxide layer from porous Mg(OH)2 to dense MgO induced by polyaniline and corrosion resistance of Mg alloy therefrom

    Science.gov (United States)

    Luo, Yizhong; Sun, Yang; Lv, Jinlong; Wang, Xianhong; Li, Ji; Wang, Fosong

    2015-02-01

    The feasibility of polyaniline emeraldine base (EB) for enhancing long-term corrosion resistance of magnesium alloy (AZ91D Mg alloy) was confirmed, since the complex impedance of Mg alloy protected by EB/epoxy resin (ER) composite coating with 10 wt% EB loading maintained around 2 GΩ cm2 even after 80 day exposure in 0.5 M NaCl solution, while that of pure ER coated analogue decreased to 0.17 MΩ cm2 only after 31 days. The improvement in corrosion resistance was attributed to the transition of interface layer from porous Mg(OH)2 dominated one underneath pure ER coating to dense MgO dominated one underneath EB/ER coating, induced by the redox interaction of EB with Mg alloy. When the EB loading in EB/ER coating increased from 0 to 10 wt%, the relative XPS peak area ratio of MgO to Mg(OH)2 increased from 0.78 to 1.18, indicating that EB behaved as effective corrosion inhibitor causing the transformation of oxide layer from porous Mg(OH)2 to dense MgO.

  17. Improving the corrosion wear resistance of AISI 316L stainless steel by particulate reinforced Ni matrix composite alloying layer

    Energy Technology Data Exchange (ETDEWEB)

    Xu Jiang; Zhuo Chengzhi; Tao Jie; Liu Linlin [Department of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016 (China); Jiang Shuyun [Department of Mechanical Engineering, Southeast University, 2 Sipailou, Nanjing 210096 (China)], E-mail: xujiang73@nuaa.edu.cn

    2009-01-07

    In order to overcome the problem of corrosion wear of AISI 316L stainless steel (SS), two kinds of composite alloying layers were prepared by a duplex treatment, consisting of Ni/nano-SiC and Ni/nano-SiO{sub 2} predeposited by brush plating, respectively, and subsequent surface alloying with Ni-Cr-Mo-Cu by a double glow process. The microstructure of the two kinds of nanoparticle reinforced Ni-based composite alloying layers was investigated by means of SEM and TEM. The electrochemical corrosion behaviour of composite alloying layers compared with the Ni-based alloying layer and 316L SS under different conditions was characterized by potentiodynamic polarization test and electrochemical impedance spectroscopy. Results showed that under alloying temperature (1000 deg. C) conditions, amorphous nano-SiO{sub 2} particles still retained the amorphous structure, whereas nano-SiC particles were decomposed and Ni, Cr reacted with SiC to form Cr{sub 6.5}Ni{sub 2.5}Si and Cr{sub 23}C{sub 6}. In static acidic solution, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO{sub 2} particles interlayer is lower than that of the Ni-based alloying layer. However, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO{sub 2} particles interlayer is prominently superior to that of the Ni-based alloying layer under acidic flow medium condition and acidic slurry flow condition. The corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiC particles interlayer is evidently lower than that of the Ni-based alloying layer, but higher than that of 316L SS under all test conditions. The results show that the highly dispersive nano-SiO{sub 2} particles are helpful in improving the corrosion wear resistance of the Ni-based alloying layer, whereas carbides and silicide phase are deleterious to that of the Ni-based alloying layer due to the fact that the preferential removal of the matrix

  18. CORROSION PROTECTION OF ND–FE–B MAGNETS VIA PHOPHATIZATION, SILANIZATION AND ELECTROSTATIC SPRAYING WITH ORGANIC RESIN COMPOSITE COATINGS

    OpenAIRE

    XIA DING; JINGJIE LI; MUSEN LI; SHENGSONG GE; XIUCHUN WANG; KAIHONG DING; SHENGLI CUI; YONGCONG SUN

    2014-01-01

    Nd–Fe–B permanent magnets possess excellent properties. However, they are highly sensitive to the attack of corrosive environment. The aim of this work is to improve the corrosion resistance of the magnets by phosphatization, silanization, and electrostatic spraying with organic resin composite coatings. Field emission scanning electron microscope (FE-SEM) and energy dispersive spectrometer (EDS) tests showed that uniform phosphate conversion coatings and spray layers were formed on the surfa...

  19. Efficientcy of corrosion protection properties of epoxy resin/cashew nut shell liquid alloy reinforced with titanium dioxide

    Directory of Open Access Journals (Sweden)

    Wilaivan Loonpooht

    2014-12-01

    Full Text Available The cure behavior of epoxy resin containing cashew nut shell liquid (CNSL and corrosion protective performance of epoxy alloy reinforced with titanium dioxide (TiO2 have been investigated. According to FTIR spectra obtained from epoxy alloys, the CNSL can be employed as a curing agent. The curing process occurred when amount of CNSL was as low as 20%wt. It was found experimentally that the CNSL used for epoxy curing should not be higher than 40%wt.in order to minimize amount CNSL left after reaction. The corrosion protective performance of epoxy alloy on aluminum sheets was carried out. The results revealed that the ability of corrosion resistance increased with the amount of TiO2 introduced into the Epoxy/CNSL film investigated. In this work, the highest corrosion resistance value was found when the TiO2 concentration of 1.5 %wt was reached.

  20. Evaluation of soil corrosivity and aquifer protective capacity using geoelectrical investigation in Bwari basement complex area, Abuja

    Indian Academy of Sciences (India)

    A E Adeniji; O V Omonona; D N Obiora; J U Chukudebelu

    2014-04-01

    Bwari is one of the six municipal area councils of the Federal Capital Territory (FCT), Abuja with its attendant growing population and infrastructural developments. Groundwater is the main source of water supply in the area, and urbanization and industrialization are the predominant contributors of contaminants to the hydrological systems. In order to guarantee a continuous supply of potable water, there is a need to investigate the vulnerability of the aquifers to contaminants emanating from domestic and industrial wastes. A total of 20 vertical electrical soundings using Schlumberger electrode array with a maximum half current electrodes separation of 300 m was employed. The results show that the area is characterized by 3–6 geoelectric subsurface layers. The measured overburden thickness ranges from 1.0 to 24.3 m, with a mean value of 7.4 m. The resistivity and longitudinal conductance of the overburden units range from 18 to 11,908 m and 0.047 to 0.875 mhos, respectively. Areas considered as high corrosivity are the central parts with > 180 m. The characteristic longitudinal unit conductance was used to classify the area into zones of good (0.7–4.49 mhos), moderate (0.2–0.69 mhos), weak (0.1–0.19 mhos), and poor (> 0.1) aquifer protective capacity. Zones characterized by materials of moderate to good protective capacity serve as sealing potential for the underlying hydrogeological system in the area. This study is aimed at delineating zones that are very prone to groundwater contamination from surface contaminants and subsurface soils that are corrosive to utility pipes buried underground. Hence the findings of this work will constitute part of the tools for groundwater development and management and structural/infrastructural development planning of the area.

  1. Local environmental conditions and the stability of protective layers on steel surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, J.P. [Technical Univ. of Denmark, Lyngby (Denmark); Bursik, A.

    1996-12-01

    Local environmental conditions determine whether the protective layers on steel surfaces are stable. With unfavorable local environmental conditions, the protective layers may be subject to damage. Taking the cation conductivity of all plant cycle streams <0.2 {mu}S/cm for granted, an adequate feed-water and - if applicable - boiler water conditioning is required to prevent such damage. Even if the mentioned conditions are met in a bulk, the local environmental conditions may be inadequate. The reasons for this may be the disregarding of interactions among material, design, and chemistry. The paper presents many possible mechanisms of protective layer damage that are directly influenced or exacerbated by plant cycle chemistry. Two items are discussed in more detail: First, the application of all volatile treatment for boiler water conditioning of drum boiler systems operating at low pressures and, second, the chemistry in the transition zone water/steam in the low pressure turbine. The latter is of major interest for the understanding and prevention of corrosion due to high concentration of impurities in the aqueous liquid phases. This is a typical example showing that local environmental conditions may fundamentally differ from the overall bulk chemistry. (au) 19 refs.

  2. Corrosion protection of SiC-based ceramics with CVD mullite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Sarin, V.; Mulpuri, R.; Auger, M. [Boston University, Boston, MA (United States) Manufacturing Engineering

    1996-04-20

    SiC based ceramics have been identified as the leading candidate materials for elevated temperature applications in harsh oxidation/corrosion environments. It has been established that a protective coating can be effectively used to avoid problems with excessive oxidation and hot corrosion. However, to date, no coating configuration has been developed that can withstand the rigorous requirements imposed by such applications. Chemical vapor deposited (CVD) mullite coatings due to their desirable properties of toughness, corrosion resistance, and good coefficient of thermal expansion match with SiC are being developed as a potential solution. Formation of mullite on ceramic substrates via chemical vapor deposition was investigated. Thermodynamic calculations performed on the AlCl{sub 3}- SiCl{sub 4}-CO{sub 2}-H{sub 2} system were used to construct equilibrium CVD phase diagrams. Through process optimization, crystalline CVD mullite coatings have been successfully grown on SiC and Si{sub 3}N{sub 4} substrates. Results from the thermodynamic analysis, process optimization, and effect of various process parameters on deposition rate and coating morphology are discussed.

  3. Development of self-healing coatings for corrosion protection on metallic structures

    Science.gov (United States)

    Stankiewicz, Alicja; Barker, Michael B.

    2016-08-01

    Inspired by biological systems, artificial self-healing materials are designed for repairing local damage caused by external factors. The rapidly expanding field of self-healing systems contains, among others, materials with well-defined surface properties. Undoubtedly, enhancing surface functionalisation, by applying smart coatings, enjoys an extensive interest. The self-healing ability is particularly essential property for corrosion protection strategies, especially when the use of one of the most effective corrosion systems, based on chromium(VI) compounds, is now banned by the current registration, evaluation, authorisation and restriction of chemicals legislation. Self-healing protective coatings are produced using macromolecular compounds, ceramics, metals and composites. Considering the wide range of available materials, the number of potential combinations seems to be unlimited. The self-healing action of such coatings is activated by appropriate stimuli: temperature changes, radiation, pH changes, pressure changes and mechanical action. In this paper, the research and practical implications of the various approaches to achieving self-healing functionality of protective coatings, as well as potential developments in this area, are explored.

  4. Evaluation of hot corrosion protection of Cr-Al and CoNiCrAlY on IN-738LC

    Energy Technology Data Exchange (ETDEWEB)

    Khajavi, M.R. [Niroo Research Institute - Chemistry and Materials Research Center - Metallurgy Dept. End of Pounak-e-Bakhtari, P.O.Box 14665-517, Post Code 1468617151, Blvd., Shahrak-e-Gharb, Tehran (Iran)]|[Shiraz University - Materials Science and Engineering Department, Engineering School, Shiraz University, Shiraz (Iran); Pasha, A. [Niroo Research Institute - Chemistry and Materials Research Center - Metallurgy Dept. End of Pounak-e-Bakhtari, P.O.Box 14665-517, Post Code 1468617151, Blvd., Shahrak-e-Gharb, Tehran (Iran); Shariat, M.H. [Shiraz University - Materials Science and Engineering Department, Engineering School, Shiraz University, Shiraz (Iran)

    2004-07-01

    A program was conducted to evaluate the relative corrosion resistance of CoNiCrAlY and Chromium modified Aluminide on IN738-LC, used for turbine blades. The corrosion experiments were performed in a laboratory tube furnace. The microstructure of coatings was characterized by using optical and scanning electron microscopy techniques. The results indicated that at a temperature of 800 deg. C the CoNiCrAlY is more protective than Cr-Al coating. (authors)

  5. New conservation materials on the base of colza oil for the steel protection against atmospheric corrosion

    OpenAIRE

    V.I. VIGDOROVICH; TSYGANKOVA L.E.; TANYGINA E.D.; TANYGIN A.YU.; SHEL N.V.

    2016-01-01

    Protective efficiency of the composition on the base of low erucic colza oil has been studied against the carbon steel corrosion in the salt solution (3 % NaCl), thermo-moisture chamber and the natural conditions. The following compositions have been used: 1. Colza oil (CO) and its components without the inhibiting additives; 2. CO with the synthetic fat acids bottoms (SFAB) additive (1-10 wt.%); 3. CO with the anticorrosion additive IFHAN 29-A (20 wt.%); 4. CO with zinc micro powder filler (...

  6. Hydrogen Silsesquioxane based silica glass coatings for the corrosion protection of austenitic stainless steel

    DEFF Research Database (Denmark)

    Lampert, Felix; Jensen, Annemette Hindhede; Din, Rameez Ud

    2016-01-01

    The application of stainless steels in hostile environments, such as concentrated acid or hot sea water, requires additional surface treatments, considering that the native surface oxide does not guarantee sufficient corrosion protection under these conditions. In the present work, silica-like thin......-film barrier coatings were deposited on AISI 316L grade austenitic stainless steel with 2B surface finish from Hydrogen Silsesquioxane (HSQ) spin-on-glass precursor and thermally cured to tailor the film properties. Results showed that curing at 500 °C resulted in a film-structure with a polymerized siloxane...

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

    Science.gov (United States)

    Ahmad, Altaf; Kumar, Anil

    2016-10-01

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

  8. Layer texture of hot-rolled BCC metals and its significance for stress-corrosion cracking of main gas pipelines

    Science.gov (United States)

    Perlovich, Yu. A.; Isaenkova, M. G.; Krymskaya, O. A.; Morozov, N. S.

    2016-10-01

    Based on data of X-ray texture analysis of hot-rolled BCC materials it was shown that the layerwise texture inhomogeneity of products is formed during their manufacturing. The effect can be explained by saturation with interstitial impurities of the surface layer, resulting in dynamical deformation aging (DDA). DDA prevents the dislocation slip under rolling and leads to an increase of lattice parameters in the external layer. The degree of arising inhomogeneity correlates with the tendency of hot-rolled sheets and obtained therefrom tubes to stress-corrosion cracking under exploitation, since internal layers have a compressive effect on external layers, and prevents opening of corrosion cracks at the tube surface.

  9. Method for inhibiting corrosion of nickel-containing alloys

    Science.gov (United States)

    DeVan, J.H.; Selle, J.E.

    Nickel-containing alloys are protected against corrosion by contacting the alloy with a molten alkali metal having dissolved therein aluminum, silicon or manganese to cause the formation of a corrosion-resistant intermetallic layer. Components can be protected by applying the coating after an apparatus is assembled.

  10. Corrosion and cathodic protection of buried pipes: study, simulation and application of solar energy; Corrosion et protection cathodique des canalisations enterrees: etude, simulation et application de l energie solaire

    Energy Technology Data Exchange (ETDEWEB)

    Laoun, Brahim; Serir, Lazhar [Unite de Recherche Appliquee en Energies Renouvelables, URAER / Zone Industrielle Gaar Taam B.P. 88 - 47001, Ghardaia, (Algeria); Niboucha, Karima [Centre de Recherche Scientifique et Technique en Soudage et Controle, CSC / Route de Dely Brahim B.P. 64 - 16000, Cheraga, Alger, (Algeria)

    2006-07-01

    Cathodic protection is intensively used on steel pipes in petroleum and gas industries. It is a technique used to prevent corrosion which transforms the whole pipe into a cathode of a corrosion cell. Two types of cathodic protection systems are usually used: 1) the galvanic protection systems which use galvanic anodes, also called sacrificial anodes being electrochemically more electronegative than the structure to be protected and 2) the imposed current systems, which through a current generator will deliver a direct current from the anode to the structure to be protected. The aim of this work is to design a cathodic protection system of a pipe by imposed current with auxiliary electric solar energy. (O.M.)

  11. Underground pipeline corrosion

    CERN Document Server

    Orazem, Mark

    2014-01-01

    Underground pipelines transporting liquid petroleum products and natural gas are critical components of civil infrastructure, making corrosion prevention an essential part of asset-protection strategy. Underground Pipeline Corrosion provides a basic understanding of the problems associated with corrosion detection and mitigation, and of the state of the art in corrosion prevention. The topics covered in part one include: basic principles for corrosion in underground pipelines, AC-induced corrosion of underground pipelines, significance of corrosion in onshore oil and gas pipelines, n

  12. THE USE OF COATINGS FOR HOT CORROSION AND EROSION PROTECTION IN TURBINE HOT SECTION COMPONENTS

    Directory of Open Access Journals (Sweden)

    Hayrettin AHLATCI

    1999-01-01

    Full Text Available High pressure turbine components are subjected to a wide variety of thermal and mechanical loading during service. In addition, the components are exposed to a highly oxidizing atmosphere which may contain contaminants such as sulphates, chlorides and sulphuorous gases along with erosive media. So the variety of surface coatings and deposition processes available for the protection of blade and vane components in gas turbines are summarised in this study. Coating types range from simple diffusion aluminides to modified aluminides and a CoCrAlY overlayer. The recommendations for corrosion-resistant coatings (for low temperature and high temperature hot corrosion environments are as follows: silicon aluminide and platinumchromium aluminide for different gas turbine section superalloys substrates. Platinum metal additions are used to improve the properties of coatings on turbine components. Inorganic coatings based on ceramic films which contain aluminium or aluminium and silicon are very effective in engines and gas turbines. Diffusion, overlayer and thermal barrier coatings which are deposited on superalloys gas turbine components by pack cementation, plasma spraying processes and a number of chemical vapour deposition, physical vapour deposition processes (such as electron beam, sputtering, ion plating are described. The principles underlying the development of protective coatings serve as a useful guide in the choice of coatings for other high temperature applications.

  13. Silica doped with lanthanum sol-gel thin films for corrosion protection

    Energy Technology Data Exchange (ETDEWEB)

    Abuin, M. [Department of Materials Physics, Complutense University at Madrid, Avda. Complutense sn, 28004 Madrid (Spain); Serrano, A. [Glass and Ceramic Institute, CSIC, C. Kelsen 5, 28049 Madrid (Spain); Llopis, J. [Department of Materials Physics, Complutense University at Madrid, Avda. Complutense sn, 28004 Madrid (Spain); Garcia, M.A. [Glass and Ceramic Institute, CSIC, C. Kelsen 5, 28049 Madrid (Spain); IMDEA Nanoscience, Fco. Tomas y Valiente 7, 28049 Madrid (Spain); Carmona, N., E-mail: n.carmona@fis.ucm.es [Department of Materials Physics, Complutense University at Madrid, Avda. Complutense sn, 28004 Madrid (Spain)

    2012-06-01

    We present here anticorrosive silica coatings doped with lanthanum ions for the protection of metallic surfaces as an alternative to chromate (VI)-based conversion coatings. The coatings were synthesized by the sol-gel method starting from silicon alkoxides and two different lanthanum precursors: La (III) acetate hydrate and La (III) isopropoxide. Artificial corrosion tests in acid and alkaline media showed their effectiveness for the corrosion protection of AA2024 aluminum alloy sheets for coating prepared with both precursors. The X-ray absorption Near Edge Structure and X-ray Absorption Fine Structure analysis of the coatings confirmed the key role of lanthanum in the structural properties of the coating determining its anticorrosive properties. - Highlights: Black-Right-Pointing-Pointer Silica sol-gel films doped with lanthanum ions were synthesized. Black-Right-Pointing-Pointer Films from lanthanum-acetate and La-alkoxide were prepared for comparison purposes. Black-Right-Pointing-Pointer La-acetate is an affordable chemical reactive preferred for the industry. Black-Right-Pointing-Pointer Films properties were explored by scanning electron microscopy and X-Ray absorption spectroscopy. Black-Right-Pointing-Pointer An alternative to anticorrosive pre-treatments for metallic surfaces is suggested.

  14. Electrochemical synthesis of polypyrrole-Al2O3 composite coating on 316 stainless steel for corrosion protection

    Science.gov (United States)

    Yan, Qun; Li, Chuanxian; Huang, Tingting; Yang, Fei

    2017-03-01

    Polypyrrole (PPy)-Al2O3 composite coating was electrochemically deposited on 316 stainless steel (316 SS) by cyclic voltammetry technique. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) were employed to understand the morphology and composition of the PPy-Al2O3 coated SS. The corrosion protection ability of the PPy-Al2O3 coating was studied using open circuit potential (Eocp)-time measurements, polarization curves, and electrochemical impedance spectroscopy (EIS) after the electrodes had been immersed in a 3.5 wt% NaCl solution as the corrosive media. The results showed that PPy-Al2O3 composite coatings have a homogeneous and smooth surface without detectable cracks. Anodic polarization analysis revealed that the hybrid films provided an exceptional barrier and corrosion protection in comparison with PPy coating. The EIS studies indicated that the charge transfer resistance increases with the presence of PPy-Al2O3. PPy-Al2O3 composite coating provides better corrosion protection and can be considered as a coating material to protect 316SS. With increase in Al2O3/Py mole ratio, PPy-Al2O3 coatings tend to exhibit a better corrosion resistance ability.

  15. Effect of chelating agent acetylacetone on corrosion protection properties of silane-zirconium sol-gel coatings

    Science.gov (United States)

    Yu, Mei; Liang, Min; Liu, Jianhua; Li, Songmei; Xue, Bing; Zhao, Hao

    2016-02-01

    The hybrid sol-gel coatings on AA2024-T3 were prepared with a silane coupling agent 3-glycidoxypropyltrimethoxysilane (GPTMS) and a metal alkoxide tetra-n-propoxyzirconium (TPOZ) as precursors. The effect of acetylacetone (AcAc) as a chelating agent on the corrosion protection properties of sol-gel coatings were evaluated and the optimal AcAc/TPOZ molar ratio was obtained. The sol-gel coatings were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The corrosion protection properties of the coatings were evaluated by means of potentiodynamic polarization study (PDS) and electrochemical impedance spectroscopy (EIS). It is demonstrated that AcAc avoids fast hydrolysis of TPOZ and benefits to form stable sols. The coating with AcAc/TPOZ molar ratio of 3 shows the best corrosion protection performance in 0.05 M NaCl solution.

  16. Evaluation of corrosion protection performance of poly(o-ethyl aniline) coated copper by electrochemical impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, Vandana, E-mail: vda_shinde@yahoo.co [Department of Physics, North Maharashtra University, Jalgaon 425 001 (India); Patil, Pradip P., E-mail: pnmu@yahoo.co.i [Department of Physics, North Maharashtra University, Jalgaon 425 001 (India)

    2010-04-15

    Poly(o-ethylaniline) coatings were synthesized on copper (Cu) by electrochemical polymerization of o-ethylaniline in an aqueous salicylate solution by using cyclic voltammetry. The performance of poly(o-ethylaniline) as protective coating against corrosion of Cu in aqueous 3% NaCl was assessed by the electrochemical impedance spectroscopy (EIS). The results of these studies demonstrate that the poly (o-ethylaniline) coating has ability to protect the Cu against corrosion. The corrosion inhibition efficiency of coating is found to be 97%. The evaluation of the impedance parameters with immersion time was studied and water uptake and delamination area were determined. The variation of the water uptake and delamination area with the immersion time provides further evidence to the protective action of the poly(o-ethylaniline).

  17. Low Temperature Curing of Hydrogen Silsesquioxane Surface Coatings for Corrosion Protection of Aluminum

    DEFF Research Database (Denmark)

    Lampert, Felix; Jensen, Annemette Hindhede; Møller, Per

    2016-01-01

    Hydrogen Silsesquioxane (HSQ) has shown to be a promising precursor for corrosion protective glass coatings for metallic substrates due to the excellent barrier properties of the films, especially in the application of protective coatings for aluminum in the automotive industry where high chemical...... stability in alkaline environments is required. The coatings have been successfully applied to stainless steel substrates. However the traditional thermal curing of HSQ involves heating to elevated temperatures, which are beyond those applicable for most industrial applications of aluminum. In this study...... low temperature processes are tested and evaluated as possible alternatives to the traditional high temperature cure. Thin HSQ films are deposited onsilicon wafers to model the degree of curing induced by the low temperature methods in comparison to thermal curing.Furthermore, the coatings are applied...

  18. Phytic acid doped polyaniline containing epoxy coatings for corrosion protection of Q235 carbon steel

    Science.gov (United States)

    Hao, Yongsheng; Sani, Luqman Abdullahi; Ge, Tiejun; Fang, Qinghong

    2017-10-01

    Corrosion protection of epoxy coatings contained with phytic acid-doped polyaniline (PANI-PA) for Q235 carbon steel was studied in this work. Synthesized PANI-PA particles were characterized by XPS, TGA, and FTIR, respectively. The coating performance was investigated by OCP, EIS, and SVET, respectively. The experimental results show that the concentration of PANI-PA has a significant influence to the barrier effect of the epoxy coating. Epoxy coating loaded with 2 wt.% PANI-PA has the best protection ability and self-healing function to a certain degree. The self-healing function of PANI-PA is attributed to the synergistic effect of the passivation of PANI and the chelation of the dedoped phytic acid ions with iron ions. Therefore, PANI-PA can be used as an effective anticorrosion pigment in future.

  19. Replacement of corrosion protection chromate primers and paints used in cryogenic applications on the Space Shuttle with wire arc sprayed aluminum coatings

    Science.gov (United States)

    Daniel, R. L.; Sanders, H. L.; Zimmerman, F. R.

    1995-01-01

    With the advent of new environmental laws restricting volatile organic compounds and hexavalent chrome emissions, 'environmentally safe' thermal spray coatings are being developed to replace the traditional corrosion protection chromate primers. A wire arc sprayed aluminum coating is being developed for corrosion protection of low pressure liquid hydrogen carrying ducts on the Space Shuttle Main Engine. Currently, this hardware utilizes a chromate primer to provide protection against corrosion pitting and stress corrosion cracking induced by the cryogenic operating environment. The wire are sprayed aluminum coating has been found to have good potential to provide corrosion protection for flight hardware in cryogenic applications. The coating development, adhesion test, corrosion test and cryogenic flexibility test results will be presented.

  20. Smart epoxy coating containing Ce-MCM-22 zeolites for corrosion protection of Mg-Li alloy

    Science.gov (United States)

    Wang, Yanli; Zhu, Yanhao; Li, Chao; Song, Dalei; Zhang, Tao; Zheng, Xinran; Yan, Yongde; Zhang, Meng; Wang, Jun; Shchukin, Dmitry G.

    2016-04-01

    The epoxy coatings containing MCM-22 and Ce-MCM-22 zeolites were prepared by coating method on the Mg-Li alloy surface. The influence of MCM-22 and Ce-MCM-22 zeolites on corrosion protection of the epoxy coating was studied. The epoxy coating containing Ce-MCM-22 zeolites showed high corrosion resistance. Artificial defects in the epoxy coating containing Ce-MCM-22 zeolites on the Mg-Li surface were produced by the needle punching. The results show that the epoxy coating containing Ce-MCM-22 zeolites exhibits self-healing corrosion inhibition capabilities. It is ascribed to the fact that the Ce3+ ions are released from MCM-22 zeolites based on ion exchange of zeolite in the corrosion process of the Mg-Li alloy substrate. MCM-22 zeolites as reservoirs provided a prolonged release of cerium ions.

  1. Refractory Materials for Flame Deflector Protection System Corrosion Control: Flame Deflector Protection System Life Cycle Cost Analysis Report

    Science.gov (United States)

    Calle, Luz Marina; Hintze, Paul E.; Parlier, Christopher R.; Coffman, Brekke E.; Kolody, Mark R.; Curran, Jerome P.; Trejo, David; Reinschmidt, Ken; Kim, Hyung-Jin

    2009-01-01

    A 20-year life cycle cost analysis was performed to compare the operational life cycle cost, processing/turnaround timelines, and operations manpower inspection/repair/refurbishment requirements for corrosion protection of the Kennedy Space Center launch pad flame deflector associated with the existing cast-in-place materials and a newer advanced refractory ceramic material. The analysis compared the estimated costs of(1) continuing to use of the current refractory material without any changes; (2) completely reconstructing the flame trench using the current refractory material; and (3) completely reconstructing the flame trench with a new high-performance refractory material. Cost estimates were based on an analysis of the amount of damage that occurs after each launch and an estimate of the average repair cost. Alternative 3 was found to save $32M compared to alternative 1 and $17M compared to alternative 2 over a 20-year life cycle.

  2. Corrosion surface protection by using titanium carbon nitride/titanium-niobium carbon nitride multilayered system

    Energy Technology Data Exchange (ETDEWEB)

    Caicedo, J.C., E-mail: jcesarca@calima.univalle.edu.co [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Amaya, C. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Laboratorio de Recubrimientos Duros, CDT-ASTIN SENA, Cali (Colombia); Cabrera, G. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Esteve, J. [Department de Fisica Aplicada i Optica, Universitat de Barcelona, Catalunya (Spain); Aperador, W. [Universidad Militar Nueva Granada Bogota D.C (Colombia); Gomez, M.E. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Prieto, P. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Centro de Excelencia en Nuevos Materiales, CENM, Calle 13 100-00 Edificio 320, espacio 1026, Cali (Colombia)

    2011-07-29

    The aim of this work is the improvement of the electrochemical behavior of 4140 steel substrate using TiCN/TiNbCN multilayered system as a protective coating. We have grown [TiCN/TiNbCN]{sub n} multilayered via reactive r.f. magnetron sputtering technique in which was varied systematically the bilayer period ({Lambda}), and the bilayer number (n), maintaining constant the total thickness of the coatings ({approx} 3 {mu}m). The coatings were characterized by X-ray diffraction (XRD), optical microscopy, electron microscopy and transmission electron microscopy assisted with selected area electron diffraction. The electrochemical properties were studied by Electrochemical Impedance Spectroscopy and Tafel curves. XRD results showed a preferential growth in the face-centered cubic (111) crystal structure for [TiCN/TiNbCN]{sub n} multilayered coatings [1]. In this work was obtained the maximum corrosion resistance for the coating with ({Lambda}) equal to 15 nm, corresponding to n = 200 bilayered. The polarization resistance and corrosion rate were around 8.6 kOhm cm{sup 2} and 7.59 . 10{sup -4} mm/year, these values were 8.6 and 0.001 times better than those showed by the uncoated 4140 steel substrate (1.0 kOhm and 0.57 mm/year), respectively. The improvement of the electrochemical behavior of the 4140 coated with this TiCN/TiNbCN multilayered system can be attributed to the presence of several interfaces that act as obstacles for the inward and outward diffusions of Cl{sup -} ion species, generating an increment in the energy or potential required for translating the corrosive ions across the coating/substrate interface. Moreover, the interface systems affect the means free path on the ions toward the metallic substrate, due to the decreasing of the defects presented in the multilayered coatings.

  3. Atmospheric corrosion of Cu, Zn, and Cu-Zn alloys protected by self-assembled monolayers of alkanethiols

    Science.gov (United States)

    Hosseinpour, Saman; Forslund, Mattias; Johnson, C. Magnus; Pan, Jinshan; Leygraf, Christofer

    2016-06-01

    In this article results from earlier studies have been compiled in order to compare the protection efficiency of self-assembled monolayers (SAM) of alkanethiols for copper, zinc, and copper-zinc alloys exposed to accelerated indoor atmospheric corrosion conditions. The results are based on a combination of surface spectroscopy and microscopy techniques. The protection efficiency of investigated SAMs increases with chain length which is attributed to transport hindrance of the corrosion stimulators in the atmospheric environment, water, oxygen and formic acid, towards the copper surface. The transport hindrance is selective and results in different corrosion products on bare and on protected copper. Initially the molecular structure of SAMs on copper is well ordered, but the ordering is reduced with exposure time. Octadecanethiol (ODT), the longest alkanethiol investigated, protects copper significantly better than zinc, which may be attributed to the higher bond strength of Cu-S than of Zn-S. Despite these differences, the corrosion protection efficiency of ODT for the single phase Cu20Zn brass alloy is equally efficient as for copper, but significantly less for the heterogeneous double phase Cu40Zn brass alloy.

  4. Diffusion Coatings as Corrosion Inhibitors

    Science.gov (United States)

    Ivanov, Radoslav; Ignatova-Ivanova, Tsveteslava

    2016-03-01

    Corrosion is the cause of irretrievable loss of huge amounts of metals and alloys. The harmful effects of corrosion can be reduced significantly by applying appropriate methods of corrosion protection. One method to protect metals against corrosion is the formation of diffusion coatings on them. High corrosion resistance is typical for the boride diffusion layers. Aluminothermy is one of the main methods for diffusion saturation of the surface of metal products with various elements, including boron, and under certain conditions with aluminum, too. Samples of steel 45 were put to aluminothermic diffusion saturation with boron in a pressurized steel container at a temperature of 1100K, for 6 hours in powdered aluminothermic mixtures. The content of B2O3 in the starting mixtures decreased from the optimum - 20% to 0%, and the content of Al and the activator - (NH4)2.4BF3 is constant, respectively 7% and 0.5%. Al2O3 was used as filler. The borided samples were tested for corrosion resistance in 10% HCl for 72 hours. The results show that their corrosion resistance depends on the composition of the starting saturating mixture (mainly on the content of B2O3), and respectively on the composition, structure, thickness and degree of adhesion of the layer to the metal base.

  5. Diffusion Coatings as Corrosion Inhibitors

    Directory of Open Access Journals (Sweden)

    Ivanov Radoslav

    2016-03-01

    Full Text Available Corrosion is the cause of irretrievable loss of huge amounts of metals and alloys. The harmful effects of corrosion can be reduced significantly by applying appropriate methods of corrosion protection. One method to protect metals against corrosion is the formation of diffusion coatings on them. High corrosion resistance is typical for the boride diffusion layers. Aluminothermy is one of the main methods for diffusion saturation of the surface of metal products with various elements, including boron, and under certain conditions with aluminum, too. Samples of steel 45 were put to aluminothermic diffusion saturation with boron in a pressurized steel container at a temperature of 1100K, for 6 hours in powdered aluminothermic mixtures. The content of В2О3 in the starting mixtures decreased from the optimum - 20% to 0%, and the content of Al and the activator - (NH42.4BF3 is constant, respectively 7% and 0.5%. Al2O3 was used as filler. The borided samples were tested for corrosion resistance in 10% HCl for 72 hours. The results show that their corrosion resistance depends on the composition of the starting saturating mixture (mainly on the content of В2О3, and respectively on the composition, structure, thickness and degree of adhesion of the layer to the metal base.

  6. Fabrication of a nanocrystalline Ni-Co/CoO functionally graded layer with excellent electrochemical corrosion and tribological performance.

    Science.gov (United States)

    Wang, Liping; Zhang, Junyan; Zeng, Zhixiang; Lin, Yiming; Hu, Litian; Xue, Qunji

    2006-09-28

    Nanocrystalline (NC) Ni-Co/CoO functionally graded materials with excellent lubricating, high anti-corrosion and anti-wear performance were fabricated by electrodeposition and subsequent cyclic thermal oxidation and quenching. Transmission electron microscopy and energy dispersive x-ray spectroscopy investigations show that bulk Ni-Co gradient deposits with an average grain size in the range of 13-40 nm demonstrated a graded structure transition from face-centred cubic to hexagonal close packed and graded composition changes from Ni-rich to Co-rich regions with the increase in deposit thickness. X-ray diffraction and x-ray photoelectron spectroscopy analysis indicated the surface layer of NC Ni-Co graded materials to be mainly composed of dense and ultrafine CoO with a (111) preferred orientation. The NC Ni-Co/CoO functionally graded materials exhibited significantly enhanced corrosion resistance in both NaOH and NaCl solutions and remarkably improved wear resistance and dry self-lubricating performance when compared with the NC Ni and Ni-Co graded deposits under dry sliding wear conditions. The higher corrosion and tribological performance of NC Ni-Co/CoO graded materials can be attributed to the graded microstructure within the deposits, the anti-corrosion barrier of a dense oxide layer and the solid lubrication effect of CoO-rich tribo-surface films.

  7. Lawsonialnermis Extract Enhances Performance of Corrosion Protection of Coated Mild Steel in Seawater

    Directory of Open Access Journals (Sweden)

    Hajar H.M.

    2016-01-01

    Full Text Available The investigation of coating incorporated with various percentages of henna has been conducted by means of weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy method. Mild steel has been studied at ambient temperature and 50°C in order to examine the effect of temperature. The potentiodynamic polarization measurements indicate that henna extract acts as a mixed inhibitor while the corrosion rate (CR value decreases as the current density (Icorr decreases in the presence of 10% henna extract for both temperatures. Surface and protective film analysis have been carried out using Fourier transform infrared (FTIR and scanning electron microscopy (SEM.The inhibition activity is mainly correlated with the major active functional groups of lawsone. The main components can be found in lawsone structures are phenols O-H, carboxylic acid C=O and alkenes C=C. The morphology of the uninhibited sample shows a rough surface of mild steel as a result of corrosion process and severe damage can be seen. In the presence of henna, a smooth surface of mild steel anda uniform deposition of henna were observed.

  8. Ceramic coatings of LA141 alloy formed by plasma electrolytic oxidation for corrosion protection.

    Science.gov (United States)

    Li, Zhijun; Yuan, Yi; Sun, Pengpeng; Jing, Xiaoyan

    2011-09-01

    Superlight Mg-Li alloy is a promising structural materials in aerospace, automobile, and electronics because of its excellent properties such as low density, high ductility, superior strength-to-weight ratio, and good damping ability. The fabrication of compact plasma electrolytic oxidation coatings with excellent corrosion resistance is valuable for the widespread application of Mg-Li alloy. Here we present a ceramic coating on the surface of Mg-14Li-1Al (LA141) alloy for corrosion protection via plasma electrolytic oxidation (PEO) in an alkaline silicate electrolyte with tungstate as an additive. X-ray photoelectron spectroscopy and thin film-X-ray diffraction analysis of coatings show that the surface coating is mainly comprised of Mg(2)SiO(4), MgO and WO(3). Scanning electron microscopy observations have revealed that the dense and compact coating formed in the presence of tungstate has less structural imperfections in comparison to the control one fabricated without use of tungstate. The effect of oxidation time on the morphology and phase composition of coatings is also examined in detail.

  9. Compatibility between pipeline anti-corrosion coating and thermal insulator in the presence of cathodic protection

    Energy Technology Data Exchange (ETDEWEB)

    Papavinasam, S.; Doiron, A.

    2008-09-15

    Standard tests were conducted to evaluate and qualify materials used for the development of oil and gas pipeline insulators operating at elevated temperatures. The aim of the study was to demonstrate the efficacy of a modified cathodic disbondment methodology for evaluating the compatibility between anti-corrosion coatings and insulators in the presence of cathodic protection (CP). The surface of the coated panels were maintained at an external surface temperature of a pipeline operating at an internal temperature of 150 degrees C. The panels were also isolated from each other as well as from the heated pipes to ensure that the cathodic disbondment tests could be conducted simultaneously. Chemical and electrochemical changes were monitored using pH, electrochemical quartz crystal microbalance (EQCM) and electrochemical impedance spectroscopy (EIS). Samples with anti-corrosion coatings and insulators of varying thickness were tested with and without an outer polyethylene jacket. Results of the tests will be presented to industry stakeholders in order to obtain further feedback. 9 refs., 1 tab., 4 appendices.

  10. Protection of aluminium by chemical nickel plating against corrosion provoked by mercury - effect of fixing coat

    Energy Technology Data Exchange (ETDEWEB)

    Fares, C.; Merati, A. [Electrochemistry and Corrosion Laboratory, EMP BP17, Bordj El Bahri. 16111 Algiers (Algeria); Belouchrani, M.A. [Engineering Materials Laboratory, EMP BP 17, Bordj El Bahri, 16111 Algiers (Algeria)

    2004-07-01

    The aluminium structures are often met in the oil installations and for certain producer countries of oil, this matter contains a certain mercury rate. Like, Aluminium in contact with this metal is degraded by amalgamation, much of efforts are provided to trap mercury upstream installations in question by the means of specific absorbers. However, this trapping is not total, and corrosion by mercury even with the state of traces always threatens. In this context, and for the intention of preserving these installations even in the presence of corrosive metal, we recommended a solution which consists in applying a metal chemical nickel coating using the sodium hypophosphite like reducer. The choice of this process is especially dictated by the complex geometry of the parts to protect. Indeed, the metallization of aluminium requires fixing coat; in our case the latter is also selected out of nickel and is deposited by 'displacement' starting from an acid bath containing of nickel sulphate in strong concentration. In experiments, it was noted that 'displacement' is not carried out instantaneously, but rather gradually according to time. So covering was followed in two manners: initially for durations of treatment ranging between 10 and 50 minutes per step of 10, then for lower durations between 2 and 8 minutes per step of 2. In the first case, the total treatment (chemical fixing coat + nickel plating) was fixed at one hour, whereas in the other case this same time was reserved only for nickel plating (external deposit). The deposits carried out were characterized by the impact of shock thermal tests for the appreciation of their adherence, and by examinations under the optic microscope and the SEM. This study was supplemented by tests of corrosion in saline medium and in the presence of mercury by using the layouts of the curves of potential according to time and the curves intensity-potential. The results obtained show that the fixing coat improves

  11. Silver deposition on polypyrrole films electrosynthesised onto Nitinol alloy. Corrosion protection and antibacterial activity.

    Science.gov (United States)

    Saugo, M; Flamini, D O; Brugnoni, L I; Saidman, S B

    2015-11-01

    The electrosynthesis of polypyrrole films onto Nitinol from sodium salicylate solutions of different concentrations is reported. The morphology and corrosion protection properties of the resulting coatings were examined and they both depend on the sodium salicylate concentration. The immobilisation of silver species in PPy films constituted by hollow rectangular microtubes was studied as a function of the polymer oxidation degree. The highest amount of silver was deposited when the coated electrode was prepolarised at -1.00V (SCE) before silver deposition, suggesting an increase in the amount of non-oxidised segments in the polymer. Finally, the antibacterial activity of the coating against the Gram positive Staphylococcus aureus and Staphylococcus epidermidis bacteria was evaluated. Both strains resulted sensitive to the modified coatings, obtaining a slightly better result against S. aureus.

  12. Effect of chelating agent acetylacetone on corrosion protection properties of silane-zirconium sol–gel coatings

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Mei, E-mail: yumei@buaa.edu.cn; Liang, Min; Liu, Jianhua; Li, Songmei; Xue, Bing; Zhao, Hao

    2016-02-15

    Graphical abstract: - Highlights: • AcAc was employed as a chelating agent in order to form stable sols. • The sol particle size depends on the concentration of AcAc. • AFM results indicate that AcAc content affects the morphology of the coatings. • Coating AcAc3 shows the optimal corrosion protection. - Abstract: The hybrid sol–gel coatings on AA2024-T3 were prepared with a silane coupling agent 3-glycidoxypropyltrimethoxysilane (GPTMS) and a metal alkoxide tetra-n-propoxyzirconium (TPOZ) as precursors. The effect of acetylacetone (AcAc) as a chelating agent on the corrosion protection properties of sol–gel coatings were evaluated and the optimal AcAc/TPOZ molar ratio was obtained. The sol–gel coatings were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The corrosion protection properties of the coatings were evaluated by means of potentiodynamic polarization study (PDS) and electrochemical impedance spectroscopy (EIS). It is demonstrated that AcAc avoids fast hydrolysis of TPOZ and benefits to form stable sols. The coating with AcAc/TPOZ molar ratio of 3 shows the best corrosion protection performance in 0.05 M NaCl solution.

  13. Corrosion Protection Performance of Nano-SiO2/Epoxy Composite Coatings in Acidic Desulfurized Flue Gas Condensates

    Science.gov (United States)

    Wang, Z. B.; Wang, Z. Y.; Hu, H. X.; Liu, C. B.; Zheng, Y. G.

    2016-09-01

    Five kinds of nano-SiO2/epoxy composite coatings were prepared on mild steels, and their corrosion protection performance was evaluated at room temperature (RT) and 50 °C (HT) using electrochemical methods combined with scanning electron microscopy (SEM). The effects of preparation and sealing processes on the corrosion protection performance of epoxy coatings were specially focused on. The results showed that it was favorable for the corrosion protection and durable performance to add the modified nano-SiO2 during rather than after the synthesis of epoxy coatings. Furthermore, the employment of sealer varnish also had beneficial effects. The two better coatings still exhibited higher impedance values even after immersion tests for up to 1000 h at RT and 500 h at HT. SEM revealed that the improvement of corrosion protection performance mainly resulted from the enhancement of coating density. Moreover, the evolution of electrochemical behavior of the two better coatings with immersion time was also discussed by means of fitting the electrochemical impedance spectroscopy results using equivalent circuits with different physical meanings.

  14. 飞机结构的腐蚀与防护%Corrosion and Protection of Aircraft Structure

    Institute of Scientific and Technical Information of China (English)

    李东帆

    2016-01-01

    Objective To study the structure corrosion of military aircraft, to accomplish corrosion repair and protection,in order to ensure the flight safety and economic operation. Methods The typical structure corrosion in the repair works was analyzed, the main causes for the corrosion were found out, and targeted repair and protection measures were taken. Results The structure corrosion of aircraft was effectively controlled,the maintenance cost was greatly reduced, the aircraft′s flight safety and service life were guaranteed. Conclusion The structure corrosion of military aircraft is more and more serious, we must put prevention at the first position, and wipe out the corrosion at the starting stage by combining prevention and repair.%目的 研究军用飞机结构腐蚀情况,做好腐蚀的修理与防护,确保飞行安全和经济运行.方法 对修理中遇到的典型飞机结构腐蚀进行分析,找出腐蚀的主要原因,并作出针对性修理与防护措施.结果 飞机结构腐蚀得到了有效的控制,维修费用大大降低,飞机的飞行安全和使用寿命得到保障.结论 军用飞机结构腐蚀越来越严重,日常维修中必须做到预防为主,防治结合,把腐蚀消灭在萌芽状态.

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

    Science.gov (United States)

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

    1988-01-01

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

  16. Corrosion Mechanism of Corrosion-Resistant Steel Developed for Bottom Plate of Cargo Oil Tanks

    Institute of Scientific and Technical Information of China (English)

    Feilong SUN; Xiaogang LI; Fan ZHANG; Xuequn CHENG; Cheng ZHOU; Nianchun WU; Yuqun YIN

    2013-01-01

    A new type of corrosion-resistant steel consisting of ferrite and bainite phases was developed for cargo oil tanks of crude oil tankers.The corrosion rate of this new steel was 0.22 mm/a,which was equivalent to ca.1/5 of the criterion (≤ 1 mm/a) for corrosion-resistant steels.The composition and element distribution of the corrosion products were investigated by micro-Raman spectrometry and energy dispersive spectrometer.The results demonstrated that the corrosion product was composed of α-FeOOH,Fe3O4 and a continuous Cu enrichment layer.This kind of corrosion product was protective to the steel matrix and accounted for the enhancement of the corrosion resistance of the new developed steel.

  17. Protecting with nature (PwN) PwN concept (bio-) corrosion prevention

    NARCIS (Netherlands)

    Mijle Meijer, van der H.; Foekema, E.M.; Leon, F.

    2014-01-01

    Harbour infrastructures, civil engineering structures and offshore structures are exposed to a very aggressive maritime environment. The local corrosion mechanism bio-corrosion or microbial influenced corrosion (MIC) seems to be the life determining failure mechanism for these structures. There is a

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

    Science.gov (United States)

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

  19. Cellulose acetate layer effect toward aluminium corrosion rate in hydrochloric acid media

    Science.gov (United States)

    Andarany, K. S.; Sagir, A.; Ahmad, A.; Deni, S. K.; Gunawan, W.

    2017-09-01

    Corrosion occurs due to the oxidation and reduction reactions between the material and its environment. The oxidation reaction defined as reactions that produce electrons and reduction is between two elements that bind the electrons. Corrosion cannot be inevitable in life both within the industry and household. Corrosion cannot eliminate but can be control. According to the voltaic table, Aluminum is a metal that easily corroded. This study attempts to characterize the type of corrosion by using a strong acid media (HCl). Experiment using a strong acid (HCl), at a low concentration that occurs is pitting corrosion, whereas at high concentrations that occurs is corrosion erosion. One of prevention method is by using a coating method. An efforts are made to slow the rate of corrosion is by coating the metal with “cellulose acetate” (CA). cellulose acetate consisted of cellulose powder dissolved in 99% acetic acid, and then applied to the aluminum metal. Soaking experiments using hydrochloric acid, cellulose acetate is able to slow down the corrosion rate of 47 479%.

  20. An Experimental Investigation of Galvanic Anode Specifications for Suitable Cathodic Corrosion Protection of Low Carbon Steel in Kaduna Metropolitan Soil

    Directory of Open Access Journals (Sweden)

    T.N. Guma

    2016-06-01

    Full Text Available The paper stresses corrosion risks from huge underground engineering steel structures within the metropolitan area of Kaduna-a top city in Nigeria. Cathodic protection (CP is examined as an effective, economical and durable method of preventing corrosion of such structures if suitably designed-installed. Variables that can cause wide differences and difficulties in CP designs such as material make, surface area and nature of structure, corrosivity level of environment, etc, are recognized. Some supplementary information that accounts for complexity of such variables which can be used to optimize CP design of the structures was sought experimentally. Relative performances by zinc, pure magnesium and magnesium alloy as common and cheap galvanic anodes were investigated in a laboratory CP of polished bare low carbon steel specimens in soil of surveyed resistivity spectrum 31.9-152.9 ohm-m from the area. Specimens were exposed with and without CP by the anodes at ambient temperature up to 40 days in various samples of the soil. Levels of specimen protections were determined by analysis of obtained information on their corrosion rates and polarized potentials relative to the un-protected ones at 8-day intervals. The analysis indicated that; corrosion of the structures can be optimally reduced to negligible rates by polarizing them to -0.85V versus Cu/CuSO4 electrode with the anodes, pure magnesium is comparatively the best of the anodes for CP of the structures in terms of economy and effectiveness followed by magnesium alloy, and a unit surface area of the anodes can protect up to nearly 1200 units of the structure with the -0.85V protective potential depending on the anode type.

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

    DEFF Research Database (Denmark)

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

    2006-01-01

    prematurely. Reinforcement corrosion is identified to be the foremost cause of deterioration. Steel in concrete is normally protected by a passive layer due the high alkalinity of the concrete pore solution; corrosion is initiated by neutralization through atmospheric carbon dioxide and by ingress...... of depassivation ions, especially chloride ions. The background and consequences of deterioration of reinforced concrete structures caused by steel corrosion are summarized. Selected corrosion mechanisms postulated in the literature are briefly discussed and related to observations. The key factors controlling...... initiation and propagation of corrosion of steel in concrete are outlined....

  2. Electrochemical measurements of cathodic protection for reinforced concrete piles in a marine environment using embedded corrosion monitoring sensors

    Science.gov (United States)

    Jeong, Jin-A.; Chung, Won-Sub; Kim, Yong-Hwan

    2013-05-01

    This study developed a sensor to monitor the corrosion of reinforced concrete structures. Concrete pile specimens with embedded sensors were used to obtain data on corrosion and cathodic protection for bridge columns in a real marine environment. Corrosion potential, cathodic protection current density, concrete resistivity, and the degree of depolarization potential were measured with the embedded sensors in concrete pile specimens. The cathodic protection (CP) state was accurately monitored by sensors installed in underwater, tidal, splash, and atmospheric zones. The protection potential measurements confirmed that the CP by Zn-mesh sacrificial anode was fairly effective in the marine pile environment. The protection current densities in the tidal, splash zones were 2-3 times higher than those in underwater and atmospheric zones. The concrete resistivity in the tidal and splash zones was decreased through the installation of both mortar-embedded Zn-mesh (sacrificial anode) and outside an FRP jacket (cover). Considering the CP, the cathodic prevention was more effective than cathodic protection.

  3. Corrosion Protection of Stainless Steel by Polyaniline/Polypyrrole Composite Coating

    Directory of Open Access Journals (Sweden)

    A.Subathira

    2010-12-01

    Full Text Available Electrochemical deposition of polyaniline/polypyrrole coatings on stainless steel was carried out by the constant potential technique. The surface properties and corrosion behavior of the coatings were studied by varying the time of deposition and the initial monomer concentration. The corrosion current and corrosion potential were measured by direct current polarization test. The changes in corrosion current and corrosion potential with the deposition timeand the initial monomer concentration were thoroughly investigated. The surface energy of coated stainless steel was calculated by using dynamic contact angle analyzer.

  4. Self-assembled nanofilm of 1,2-dihydro-3-(octadecylthio)benzotriazine on copper for corrosion protection

    Indian Academy of Sciences (India)

    B V Appa Rao; M D Yakub Iqbal; M Narsihma Reddy; K Chaitanya Kumar

    2014-04-01

    The self-assembled nanofilm of 1,2-dihydro-3-(octadecylthio)benzotriazine (DOTBT) was formed on fresh copper surface obtained by etching with 7 N nitric acid at a room temperature of 30°C. The conditions for formation of the DOTBT nanofilm have been optimized by electrochemical impedance and electrochemical quartz crystal nanobalance (EQCN) studies. The DOTBT nanofilm on copper surface was characterized by contact-angle measurement, X-ray photoelectron spectra (XPS), reflection absorption FTIR spectra and atomic force micrographs (AFM). It is inferred that formation of DOTBT film is due to chemisorption of DOTBT on copper surface through nitrogen and subsequent complex formation between DOTBT and Cu+ ions. Corrosion protection ability of DOTBT nanofilm was evaluated in dilute aqueous NaCl solution using electrochemical impedance, potentiodynamic polarization, weight-loss and XPS studies. These studies inferred that the DOTBT film protects effectively copper from corrosion. Potentiodynamic polarization studies revealed that the DOTBT film inhibits corrosion by controlling the cathodic reaction. The mechanism of corrosion protection of copper by DOTBT nanofilm is discussed in this paper.

  5. Study of the properties of plasma deposited layers of nickel-chrome-aluminium-yttrium coatings resistant to oxidation and hot corrosion

    Directory of Open Access Journals (Sweden)

    Mihailo R. Mrdak

    2012-04-01

    Full Text Available The aim of this study was to examine the properties of Ni22Cr10Al1Y layers in order to obtain optimal structural - mechanical properties with the optimization of depositing parameters. Powder was deposited by the atmospheric plasma spray (APS process with the current intensity of 600, 700 and 800A, with a corresponding plasma gun power supply of 22KW, 34KW and 28KW. The evaluation of the Ni22Cr10Al1Y coating layers was made on the basis of their microhardness, tensile strength and microstructure performance. The best performance was obtained in the layers deposited with 800A and the 34KW plasma gun power supply. The coating with the best characteristics was tested to oxidation in the furnace for heat treatment without a protective atmosphere at 1100°C for one hour. The examination of the morphology of Ni22Cr10Al1Y powder particles was carried out on the SEM (Scanning Electron Microscope as well as the EDS analysis of the best layers. The microstructure of the deposited coating layers was examined with a light microscope. The microstructure analysis was performed according to the TURBOMECA standard. The mechanical properties of layers were evaluated by the method HV0.3 for microhardness and by tensile testing for bond strength. The research has shown that plasma gun power supply significantly affects the mechanical properties and microstructure of coatings that are of crucial importance for the protection of components exposed to high temperature oxidation and hot corrosion.

  6. Corrosion resistance of Zn-Al layered double hydroxide/poly(lactic acid) composite coating on magnesium alloy AZ31

    Science.gov (United States)

    Zeng, Rong-Chang; Li, Xiao-Ting; Liu, Zhen-Guo; Zhang, Fen; Li, Shuo-Qi; Cui, Hong-Zhi

    2015-12-01

    A Zn-Al layered double hydroxide (ZnAl-LDH) coating consisted of uniform hexagonal nano-plates was firstly synthesized by co-precipitation and hydrothermal treatment on the AZ31 alloy, and then a poly(lactic acid) (PLA) coating was sealed on the top layer of the ZnAl-LDH coating using vacuum freeze-drying. The characteristics of the ZnAl-LDH/PLA composite coatings were investigated by means of XRD, SEM, FTIR and EDS. The corrosion resistance of the coatings was assessed by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that the ZnAl-LDH coating contained a compact inner layer and a porous outer layer, and the PLA coating with a strong adhesion to the porous outer layer can prolong the service life of the ZnAl-LDH coating. The excellent corrosion resistance of this composite coating can be attributable to its barrier function, ion-exchange and self-healing ability.

  7. In-line fiber Bragg grating sensors for steel corrosion detection

    Science.gov (United States)

    Deng, Fodan; Huang, Ying; Azarmi, Fardad

    2016-04-01

    A corrosion monitoring system for steel using Fiber Bragg grating (FBG) sensors is proposed. FBG sensors were protected by hypodermic tubes and a layer of adhesive. The increase in volume caused by the presence of corrosion product introduces strain that can be monitored by FBG sensors. Experimental results showed a positive correlation between the strain and corrosion product, and the change in central wavelength has the potential to serve as an indicator for material weight loss due to corrosion.

  8. Self-assembled 1-octadecyl-1H-benzimidazole film on copper surface for corrosion protection

    Indian Academy of Sciences (India)

    B V Appa Rao; M Marsihma Reddy

    2013-11-01

    Films of 1-octadecyl-1H-benzimidazole (OBI) have been formed on copper surface by selfassembly method. Optimum conditions viz. the solvent, concentration of OBI, immersion period and temperature for the formation of a protective film on copper have been established using impedance studies. The OBI film has been characterized by X-ray photoelectron spectroscopy, reflection absorption Fourier transform infrared (FTIR) spectroscopy, contact angle measurements and atomic force microscopy. Efficiency of the OBI film to protect copper from corrosion has been investigated in aq. HCl solution using electrochemical impedance spectroscopy, potentiodynamic polarization method, cyclic voltammetry, scanning electron microscopy and gravimetry. Results of these studies inferred that the OBI film has an inhibition efficiency in the range of 97-99% under different conditions. Polarization studies inferred that the OBI film functions as a cathodic inhibitor. Cyclic voltammetric studies showed that the film is stable even after 15 cycles, when the copper electrode is polarized to an anodic potential of 0.35V vs. Ag/AgCl electrode.

  9. Mechanical properties and corrosion behavior of the nitriding surface layer of Ti−6Al−7Nb using large pulsed electron beam (LPEB)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jisoo; Lee, Woo Jin; Park, Hyung Wook, E-mail: hwpark@unist.ac.kr

    2016-09-15

    Large pulsed electron beam (LPEB) irradiation was used as a single surface finishing process for Ti−Al−7Nb. Nitrogen plasma gas and cathodic apparatus have been adopted to induce nitriding effect of Ti−6Al−7Nb during the electron beam irradiation. The atomic concentration of nitrogen atoms at the re-solidified layer could be t5achieved up to ∼18% by LPEB nitriding. Nano-hardness in the re-solidified layer was improved by ∼75% following the irradiation process, as a result of a phase transformation and the formation of TiN. The re-solidified layer induced by the LPEB nitriding, consisted of TiN, TiO{sub 2}, and TiO{sub x}N{sub y}, indicated significantly modified corrosion resistance showing a nobler corrosion potential, decreased corrosion current density, and improved charge transfer resistance. The increasing fraction of TiN at the re-solidified layer, induced by LPEB nitriding, was suggested as being responsible for remarkable improvement of mechanical properties and corrosion resistance, embedding uniformly noble and stable characteristics at the top surface. The corrosion-resistant surface layer with superior mechanical properties on Ti−6Al−7Nb has been successfully demonstrated by LPEB nitriding technique. - Highlights: • The nitrogen plasma source facilitated the formation of TiN at the re-solidified layer induced by LPEB. • The negative DC bias increased TiN fraction at the re-solidified layer. • The passivation of re-solidified layer enhanced corrosion resistance of Ti−6Al−7Nb. • The formation of uniformly stable oxy-nitride layer increased corrosion resistance. • Large pulsed electron beam irradiation with N{sub 2} plasma source generated surface hardening.

  10. Erosion-corrosion characteristic of nano-particulates reinforced Ni-Cr-Mo-Cu surface alloying layer in acidic flow and acidic slurry flow

    Energy Technology Data Exchange (ETDEWEB)

    Xu, J.; Zhuo, C. [Department of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing (China)

    2010-01-15

    In order to improve the corrosion and erosion-corrosion resistance of 316L stainless steel in engineering application, two kinds of composite alloying layers were prepared by a duplex treatment, consisting of Ni/nano-SiC and Ni/nano-SiO{sub 2} predeposited by brush plating, respectively, and a subsequent surface alloying with Ni-Cr-Mo-Cu by double glow process. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were performed on the two kinds of composite alloying layer using 10 wt% HCl solution to assess the corrosion behavior. Erosion-corrosion tests were carried out by erosion-corrosion test rig in acidic flow and acidic slurry flow for test time of 20 h at four different rotational speeds. Results of electrochemical tests indicated that the corrosion resistance of composite alloying layer with brush plating Ni/nano-SiO{sub 2} particles interlayer approximated to that of single Ni-based alloying layer, whereas the corrosion resistance of the composite alloying layer with brush plating Ni/nano-SiC particles interlayer was apparently inferior to that of Ni-based alloying layer in 10 wt% HCl solution at static state. Under the conditions of acidic flow and acidic slurry flow, the mass losses of tested samples increased with increase in the time of erosion-corrosion tests and the rotational speeds of samples. The mass losses of composite alloying layer with brush plating Ni/nano-SiO{sub 2} particles interlayer were lower than that of single Ni-based alloying layer at all rotational speeds, except at 1.88 m/s in acidic flow. The mass losses of composite alloying layer with brush plating Ni/nano-SiC particles interlayer were higher than that of single Ni-based alloying layer at all rotational speeds, but were obviously lower than that of AISI 316L stainless steel. The influences of second phase on the corrosion and erosion-corrosion of the two kinds of composite alloying layer were discussed in this paper. (Abstract Copyright [2010], Wiley

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

    Science.gov (United States)

    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

  12. High-Temperature Corrosion of Protective Coatings for Boiler Tubes in Thermal Power Plants

    Institute of Scientific and Technical Information of China (English)

    XU Lianyong; JING Hongyang; HUO Lixing

    2005-01-01

    High-temperature corrosion is a serious problem for the water-wall tubes of boilers used in thermal power plants. Oxidation, sulfidation and molten salt corrosion are main corrosion ways.Thereinto, the most severe corrosion occurs in molten salt corrosion environment. Materials rich in oxides formers, such as chromium and aluminum, are needed to resist corrosion in high-temperature and corrosive environment, but processability of such bulk alloys is very limited. High velocity electric arc spraying (HVAS) technology is adopted to produce coatings with high corrosion resistance. By comparison, NiCr (Ni-45Cr-4Ti) is recommended as a promising alloy coating for the water-wall tubes, which can even resist molten salt corrosion attack. In the study of corrosion mechanism, the modern material analysis methods, such as scanning electron microscopy (SEM), X-ray diffractometry (XRD) and energy dispersive spectrometry (EDS), are used. It is found that the corrosion resistances of NiCr and FeCrAI coatings are much better than that of 20g steel, that the NiCr coatings have the best anti-corrosion properties, and that the NiCr coatings have slightly lower pores than FeCrAI coatings.It is testified that corrosion resistance of coatings is mainly determined by chromium content, and the microstructure of a coating is as important as the chemical composition of the material. In addition, the fracture mechanisms of coatings in the cycle of heating and cooling are put forward. The difference of the thermal physical properties between coatings and base metals results in the thermal stress inside the coatings. Consequently, the coatings spall from the base metal.

  13. Optimisation of the phosphate conversion treatment for generating protective coatings; Optimizacion del tratamiento de fosfatado como metodo de proteccion frente a la corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Onofre-Bustamante, E.; Olvera, A.; Barba, A.; Rodriguez, F. J.; Carboneras, M.; Alvarez, M.; Garcia-Alonso, M. C.; Escudero, M. L.

    2010-07-01

    This paper evaluates the phosphate treatment as a chemical conversion treatment (CCT) free of chromium, from the basis of the study of a commercial treatment applied in phosphoric solution at different concentrations (100% and dilutions 1:2, 1:5 and 1:10). The optimum immersion time for the phosphate conversion treatment was established from the evolution over time of the open circuit potential. Protection against corrosion of the conversion layers was evaluated by polarisation resistance and electrochemical impedance measurements. The adhesion to the substrate was evaluated by pull-off tests. Results have shown that the application of an organic coating on the substrate with a previous phosphate treatment in 1:5 dilution (10 min.) increases the corrosion resistance in, at least, one order of magnitude with respect to the non phosphate-coated metal and improves the adhesion to the substrate, since the conversion layer obtained is part of the substrate and the surface generated increases the number and area of active sites. (Author)

  14. Effect of surface roughness on leakage current and corrosion resistance of oxide layer on AZ91 Mg alloy prepared by plasma electrolytic oxidation

    Science.gov (United States)

    Yoo, Bongyoung; Shin, Ki Ryoung; Hwang, Duck Young; Lee, Dong Heon; Shin, Dong Hyuk

    2010-09-01

    The influence of the surface roughness of Mg alloys on the electrical properties and corrosion resistance of oxide layers obtained by plasma electrolytic oxidation (PEO) were studied. The leakage current in the insulating oxide layer was enhanced by increasing the surface roughness, which is a favorable characteristic for the material when applied to hand-held electronic devices. The variation of corrosion resistance with surface roughness was also investigated. The corrosion resistance was degraded by the increasing surface roughness, which was confirmed with DC polarization and impedance spectroscopy. Pitting corrosion on the passive oxide layer was also analyzed with a salt spray test, which showed that the number of pits was not affected by the surface roughness when the spray time reached 96 h.

  15. Cathodic corrosion protection in a gas distribution grid. Operational experience in five years of operation; Kathodischer Korrosionsschutz in einem Gasverteilungsnetz. Betriebserfahrung nach fuenf Jahren

    Energy Technology Data Exchange (ETDEWEB)

    Poka, Werner [Stadtwerke Straubing (Germany); Gaugler, Hans; Steiger, Oliver [Stadtwerke Muenchen (Germany)

    2011-07-01

    In late 2001, Stadtwerke Straubing in Bavaria decided on cathodic corrosion protection of the Straubing low-pressure grid, with about 120 km of steel pipes. Planning started in early 2002 in cooperation with Stadtwerke Munich (SWM). Three years later, in December 2005, the last of the 25 grid sections was integrated in the cathodic corrosion protection system. This was followed by two years of monitoring, documentation, and measurements. The effectiveness of the cathodic corrosion protection system was proved for the whole low-pressure grid. Cost was reduced and availability enhanced. The project is discussed in detail, including economic efficiency, leak frequency and condition monitoring on the basis of measurements.

  16. Three-Layer PE Corrosion-Inhibiting Coating for Steel Pipeline

    Institute of Scientific and Technical Information of China (English)

    Li Aiguo; Zheng Aijing

    1994-01-01

    @@ RIET (Research Institute of Engineering Technology of China National Petroleum Corporation)had got a lender contract for manufacturing corrosion-inhibiting coating for steel pipe piles through international competitive bidding in the extension section project of Dandong Port (China)in 1992. The contract had been completed by May 1993. Now, brief descriptions of the corrosion-inhibiting coating manufactured by RIETare presented as following.

  17. Corrosion Resistance Behavior of Single-Layer Cathodic Arc PVD Nitride-Base Coatings in 1M HCl and 3.5 pct NaCl Solutions

    Science.gov (United States)

    Adesina, Akeem Yusuf; Gasem, Zuhair M.; Madhan Kumar, Arumugam

    2017-04-01

    The electrochemical behavior of single-layer TiN, CrN, CrAlN, and TiAlN coatings on 304 stainless steel substrate, deposited using state-of-the-art and industrial size cathodic arc PVD machine, were evaluated in 1M HCl and 3.5 pct NaCl solutions. The corrosion behavior of the blank and coated substrates was analyzed by electrochemical impedance spectroscopy (EIS), linear polarization resistance, and potentiodynamic polarization. Bond-coat layers of pure-Ti, pure-Cr, alloyed-CrAl, and alloyed-TiAl for TiN, CrN, CrAlN, and TiAlN coatings were, respectively, first deposited for improved coating adhesion before the actual coating. The average coating thickness was about 1.80 µm. Results showed that the corrosion potentials ( E corr) of the coated substrates were shifted to more noble values which indicated improvement of the coated substrate resistance to corrosion susceptibility. The corrosion current densities were lower for all coated substrates as compared to the blank substrate. Similarly, EIS parameters showed that these coatings possessed improved resistance to defects and pores in similar solution compared to the same nitride coatings developed by magnetron sputtering. The charge transfer resistance ( R ct) can be ranked in the following order: TiAlN > CrN > TiN > CrAlN in both media except in NaCl solution where R ct of TiN is lowest. While the pore resistance ( R po) followed the order: CrAlN > CrN > TiAlN > TiN in HCl solution and TiAlN > CrN > CrAlN > TiN in NaCl solution. It is found that TiAlN coating has the highest protective efficiencies of 79 and 99 pct in 1M HCl and 3.5 pct NaCl, respectively. SEM analysis of the corroded substrates in both media was also presented.

  18. Corrosion Resistance Behavior of Single-Layer Cathodic Arc PVD Nitride-Base Coatings in 1M HCl and 3.5 pct NaCl Solutions

    Science.gov (United States)

    Adesina, Akeem Yusuf; Gasem, Zuhair M.; Madhan Kumar, Arumugam

    2017-01-01

    The electrochemical behavior of single-layer TiN, CrN, CrAlN, and TiAlN coatings on 304 stainless steel substrate, deposited using state-of-the-art and industrial size cathodic arc PVD machine, were evaluated in 1M HCl and 3.5 pct NaCl solutions. The corrosion behavior of the blank and coated substrates was analyzed by electrochemical impedance spectroscopy (EIS), linear polarization resistance, and potentiodynamic polarization. Bond-coat layers of pure-Ti, pure-Cr, alloyed-CrAl, and alloyed-TiAl for TiN, CrN, CrAlN, and TiAlN coatings were, respectively, first deposited for improved coating adhesion before the actual coating. The average coating thickness was about 1.80 µm. Results showed that the corrosion potentials (E corr) of the coated substrates were shifted to more noble values which indicated improvement of the coated substrate resistance to corrosion susceptibility. The corrosion current densities were lower for all coated substrates as compared to the blank substrate. Similarly, EIS parameters showed that these coatings possessed improved resistance to defects and pores in similar solution compared to the same nitride coatings developed by magnetron sputtering. The charge transfer resistance (R ct) can be ranked in the following order: TiAlN > CrN > TiN > CrAlN in both media except in NaCl solution where R ct of TiN is lowest. While the pore resistance (R po) followed the order: CrAlN > CrN > TiAlN > TiN in HCl solution and TiAlN > CrN > CrAlN > TiN in NaCl solution. It is found that TiAlN coating has the highest protective efficiencies of 79 and 99 pct in 1M HCl and 3.5 pct NaCl, respectively. SEM analysis of the corroded substrates in both media was also presented.

  19. Corrosion Resistance of the Superhydrophobic Mg(OH2/Mg-Al Layered Double Hydroxide Coatings on Magnesium Alloys

    Directory of Open Access Journals (Sweden)

    Fen Zhang

    2016-04-01

    Full Text Available Coatings of the Mg(OH2/Mg-Al layered double hydroxide (LDH composite were formed by a combined co-precipitation method and hydrothermal process on the AZ31 alloy substrate in alkaline condition. Subsequently, a superhydrophobic surface was successfully constructed to modify the composite coatings on the AZ31 alloy substrate using stearic acid. The characteristics of the composite coatings were investigated by means of X-ray diffractometer (XRD, Fourier transform infrared spectroscopy (FTIR, X-ray photoelectron spectroscopy (XPS, scanning electronic microscope (SEM and contact angle (CA. The corrosion resistance of the coatings was assessed by potentiodynamic polarization, the electrochemical impedance spectrum (EIS, the test of hydrogen evolution and the immersion test. The results showed that the superhydrophobic coatings considerably improved the corrosion resistant performance of the LDH coatings on the AZ31 alloy substrate.

  20. Smart epoxy coating containing Ce-MCM-22 zeolites for corrosion protection of Mg-Li alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanli, E-mail: yanliwang@hrbeu.edu.cn [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Stephenson Institute for Renewable Energy, Department of Chemistry, University of Liverpool, Peach Street, Liverpool L69 7ZF (United Kingdom); Zhu, Yanhao; Li, Chao; Song, Dalei; Zhang, Tao; Zheng, Xinran; Yan, Yongde; Zhang, Meng; Wang, Jun [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Shchukin, Dmitry G. [Stephenson Institute for Renewable Energy, Department of Chemistry, University of Liverpool, Peach Street, Liverpool L69 7ZF (United Kingdom)

    2016-04-30

    Graphical abstract: - Highlights: • The self-healing behaviour of the epoxy coating containing Ce-MCM-22 zeolites on the Mg-Li alloy was studied. • MCM-22 zeolites as reservoirs provide a prolonged release of cerium ions. • The epoxy coating containing Ce-MCM-22 zeolites provides effective long-term active protection for the Mg-Li alloy. - Abstract: The epoxy coatings containing MCM-22 and Ce-MCM-22 zeolites were prepared by coating method on the Mg-Li alloy surface. The influence of MCM-22 and Ce-MCM-22 zeolites on corrosion protection of the epoxy coating was studied. The epoxy coating containing Ce-MCM-22 zeolites showed high corrosion resistance. Artificial defects in the epoxy coating containing Ce-MCM-22 zeolites on the Mg-Li surface were produced by the needle punching. The results show that the epoxy coating containing Ce-MCM-22 zeolites exhibits self-healing corrosion inhibition capabilities. It is ascribed to the fact that the Ce{sup 3+} ions are released from MCM-22 zeolites based on ion exchange of zeolite in the corrosion process of the Mg-Li alloy substrate. MCM-22 zeolites as reservoirs provided a prolonged release of cerium ions.

  1. A new dioxime corrosion inhibitor for the protection and conservation of copper: synthesis, characterization and evaluation in acidic chloride solution

    Science.gov (United States)

    Abu-Baker, Ahmad N.; Al-Qudah, Mahmoud A.

    2016-08-01

    This study aimed to investigate a new dioxime compound as a corrosion inhibitor for copper. The compound (4,6-dihydroxy benzene-1,3-dicarbaldehyde dioxime) was synthesized and characterized by nuclear magnetic resonance spectroscopy. Electrochemical impedance spectroscopy and potentiodynamic polarization measurements were used to compare the dioxime compound with benzotriazole for their effectiveness as corrosion inhibitors for copper in 0.1 M HCl solution. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were used to investigate the bonding mechanisms and morphological changes of the two inhibitors on the copper surface. The electrochemical techniques showed that the new dioxime compound was more effective than benzotriazole in inhibiting copper corrosion in the acidic chloride medium. The FTIR and SEM results indicated that the dioxime compound was able to coordinate with copper ions and formed a protective film on the copper surface. It was concluded that the new dioxime compound proved effectiveness to be used as a corrosion inhibitor for the protection and conservation of copper.

  2. Effects of CeO2 on microstructure and corrosion resistance of TiC-VC reinforced Fe-based laser cladding layers

    Institute of Scientific and Technical Information of China (English)

    张辉; 邹勇; 邹增大; 史传伟

    2014-01-01

    The effects of CeO2 on microstructure and corrosion resistance of TiC-VC reinforced Fe-based laser cladding layers were investigated. The results showed that carbides presented in cladding layers were TiVC2 and VC. A small quantity of CeC appeared with 2.0 wt.%CeO2 addition. The amount of lamellar pearlite increased while the amount of residual austenite decreased with in-creasing CeO2 addition. The corrosion resistance of cladding layers increased firstly and then decreased with the addition of CeO2 in-creasing. The EIS spectrum of the cladding layer without CeO2 was composed of an inductive arc at low frequency and a capacitive arc at high frequency. The cladding layer with 0.5 wt.%CeO2 addition showed the best corrosion resistance, and then the inductive arc at low frequency transformed into a capacitive arc.

  3. Corrosion and Protection of Atmospheric Tower%常压塔的腐蚀与防护

    Institute of Scientific and Technical Information of China (English)

    陈碧凤; 杨启明

    2009-01-01

    According to the corrosion happened in different places of the atmospheric tower. Analyze the corrosion mechanism, study the main factors affecting the equipment corrosion and raise some corresponding measures to avoid corrosion.%本文针对常压装置各个部位存在的腐蚀问题,分析了其腐蚀机理,研究出影响其腐蚀的主要因素,并提出相应的防腐蚀措施.

  4. Diamond-based protective layer for optical biosensors

    Science.gov (United States)

    Majchrowicz, D.; Ficek, M.; Baran, T.; WÄ sowicz, M.; Struk, P.; Jedrzejewska-Szczerska, M.

    2016-09-01

    Optical biosensors have become a powerful alternative to the conventional ways of measurement owing to their great properties, such as high sensitivity, high dynamic range, cost effectiveness and small size. Choice of an optical biosensor's materials is an important factor and impacts the quality of the obtained spectra. Examined biological objects are placed on a cover layer which may react with samples in a chemical, biological and mechanical way, therefore having a negative impact on the measurement reliability. Diamond, a metastable allotrope of carbon with sp3 hybridization, shows outstanding properties such as: great chemical stability, bio-compatibility, high thermal conductivity, wide bandgap and optical transparency. Additionally it possesses great mechanical durability, which makes it a long-lasting material. The protective diamond thin films were deposited on the substrate using Microwave Plasma Assisted Chemical Vapor Deposition (MW PA CVD) system. The surface morphology and roughness was assessed with atomic force microscopy and profilometry. We have performed a series of measurements to assess the biocompatibility of diamond thin films with whole blood. The results show that thin diamond protective layer does not affect the red blood cells, while retaining the sensors high resolution and dynamic range of measurement. Therefore, we conclude that diamond thin films are a viable protective coating for optical biosensors, which allows to examine many biological elements. We project that it can be particularly useful not only for biological objects but also under extreme conditions like radioactive or chemically aggressive environments and high temperatures.

  5. Synthesis of Graphene Oxide-Based Sulfonated Oligoanilines Coatings for Synergistically Enhanced Corrosion Protection in 3.5% NaCl Solution.

    Science.gov (United States)

    Lu, Hao; Zhang, Shengtao; Li, Weihua; Cui, Yanan; Yang, Tao

    2017-02-01

    As a vital derivative of graphene, graphene oxide (GO) is widely applied in various fields, such as transparent electrodes, solar cells, energy storage, and corrosion protection due to the large specific surface area and abundant active sites. However, compared with graphene, the application of GO has been less reported in metal corrosion protection field. Therefore, in our study, 3-aminobenzenesulfonic acid was selected to combine with oligoanilines to fabricate the GO-based sulfonated oligoanilines coatings for marine corrosion protection application. The obtained composite coatings were covered on the surface of Q235 steel, which is one of the most important structural marine materials. Fourier transform infrared spectra were utilized to prove the existence of different bonds and functional groups of aniline trimer and sulfonated aniline trimer (SAT). Scanning electron microscopy was applied to verify the combination of GO and SAT. What's more, transmission electron microscopy was applied to observe the surface appearance of the obtained GO-SAT composite material. Besides, the results of electrochemical measurements performed in 3.5 wt % NaCl solution showed excellent corrosion-protective properties of GO/SAT-coated epoxy resin with a dosage of 10 mg of GO compared with the pure epoxy resin. Moreover, the enhancement of surface hydrophobic property, to some extent, is in favor of preventing the absorption of corrosive medium and water molecules revealed by contact angle test. The addition of GO can make the diffusion pathway of the corrosive medium longer and more circuitous, while SAT has displayed excellent solvent solubility while maintaining corrosion-protective properties similar to those of polyanilines so that the corrosion-protective properties of the modified coatings improve significantly due to the synergistically enhanced corrosion protection of GO and SAT.

  6. Stainless steel protection by in-situ oxide layer formation in stagnant lead-bismuth eutectic

    Energy Technology Data Exchange (ETDEWEB)

    Soler, L. [CIEMAT, Edificio 30, Dpto. Fision Nuclear, Avda. Complutense 22, 28040 Madrid, (Spain); Martin, F.J.; Hernandez, F.; Gomez-Briceno, D. [CIEMAT, Nuclear Fission Department, Structural Materials Project, Avda. Complutense 22, Building 30, 28040 Madrid (Spain)

    2004-07-01

    Accelerator Driven Systems (ADS) are designed to transmute long life and high activity nuclear wastes. The physico-chemical and nuclear characteristics of lead bismuth eutectic make this heavy liquid metal suitable to be used as spallation target and as coolant in ADS. However, heavy liquid metals, and particularly lead-bismuth eutectic, present a high aggressiveness to most of the structural materials. Nickel, chromium and iron, as constitutive elements of stainless steels, show a high solubility in lead-bismuth eutectic, that prevents their use as structural materials without any protection at temperatures higher than 400 deg. C for austenitic stainless steels and higher than 450 deg. C for martensitic steels. According to the available experience, proceeding from the former USSR, one of the possible ways to improve the performance of structural materials in Pb-Bi is the formation and maintenance of a protective oxide layer, which would constitute a barrier between the liquid metal and the steel. The corrosion resistance is determined by the oxygen thermodynamic activity in the liquid metal. For oxygen concentrations in the liquid metal below the equilibrium concentration for the formation of protective layers, the structural steels will suffer dissolution attack. On the contrary, if the oxygen concentration is higher than the necessary for the formation of oxide layers, the steels will experience an oxidation process, but very high concentrations provoke lead-bismuth oxides. Therefore, the oxygen content should be between these two limits in order to be able to form a protective oxide on the steel surface. The necessary oxygen content in the liquid metal may be obtained by gas injection, lead oxide interacting with the melt or the H{sub 2}/H{sub 2}O system. In this work, materials protection by 'in situ' oxidation has been studied in stagnant lead-bismuth, with different oxygen levels (H{sub 2}/H{sub 2}O ratios of 0.3, 0.03 and 0.003), at temperatures

  7. Protecting polymers in space with atomic layer deposition coatings.

    Science.gov (United States)

    Minton, Timothy K; Wu, Bohan; Zhang, Jianming; Lindholm, Ned F; Abdulagatov, Aziz I; O'Patchen, Jennifer; George, Steven M; Groner, Markus D

    2010-09-01

    Polymers in space may be subjected to a barrage of incident atoms, photons, and/or ions. Atomic layer deposition (ALD) techniques can produce films that mitigate many of the current challenges for space polymers. We have studied the efficacy of various ALD coatings to protect Kapton polyimide, FEP Teflon, and poly(methyl methacrylate) films from atomic-oxygen and vacuum ultraviolet (VUV) attack. Atomic-oxygen and VUV studies were conducted with the use of a laser-detonation source for hyperthermal O atoms and a D2 lamp as a source of VUV light. These studies used a quartz crystal microbalance (QCM) to monitor mass loss in situ, as well as surface profilometry and scanning electron microscopy to study the surface recession and morphology changes ex situ. Al2O3 ALD coatings protected the underlying substrates from atomic-oxygen attack, and the addition of TiO2 coatings protected the substrates from VUV-induced damage. The results indicate that ALD coatings can simultaneously protect polymers from oxygen-atom erosion and VUV radiation damage.

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

    DEFF Research Database (Denmark)

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

    2005-01-01

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

  11. Anti corrosion layer for stainless steel in molten carbonate fuel cell - comprises phase vapour deposition of titanium nitride, aluminium nitride or chromium nitride layer then oxidising layer in molten carbonate electrolyte

    DEFF Research Database (Denmark)

    2000-01-01

    Forming an anticorrosion protective layer on a stainless steel surface used in a molten carbonate fuel cell (MCFC) - comprises the phase vapour deposition (PVD) of a layer comprising at least one of titanium nitride, aluminium nitride or chromium nitride and then forming a protective layer in situ...

  12. GALVANIC CORROSION AND PROTECTION OF GECM/LY12CZ COUPLES UNDER DIFFERENT ATMOSPHERIC EXPOSURE CONDITIONS

    Institute of Scientific and Technical Information of China (English)

    F.Lu; Q.P.Zhong; 等

    2003-01-01

    Galvanic compatibility between graphite epoxy composite materials (GECM) and LY12CZ aluminum alloy was evaluated in different atmospheric corrosion environ-ments and by laboratory electrochemical measurements.Open circuit potential elec-trochemical measurements showed a relatively large potemtial difference about 1 volt between the GECM and LY12CZ aluminum alloy,and this difference provided the driving force for galvanic corrosion of the LY12CZ aluminum alloy as an anode. Having been exposed for 1,3or 5years in Beijing,Tuandao and Wanning station,GECM/LY12CZ couples showed significant losses of strength and elongation.Protec-tive coatings and non-conductive barriers breaking the galvanic corrosion circuit were evaluated under the same atmospheric corrosive conditions.Epoxy primer paint,glass cloth barriers and LY12CZ anodizing were effective in glvanic corrosion control for GECM/LY12CZ couples.

  13. Effectiveness of concrete to protect steel reinforcement from corrosion in marine structures

    Energy Technology Data Exchange (ETDEWEB)

    1988-01-01

    A laboratory evaluation of how variations in cover design and properties determine its effectiveness in controlling corrosion in reinforced concretes in marine structures is described. The effect of concrete type and composition on chloride ingress and corrosion rate was studied for four simulated marine environments. Contrary to expectation, significant corrosion did not take place in reinforcement placed at 30 mm cover after 30 months exposure, even in concretes of lower strengths and higher water/cement ratios than mixes employed in the North Sea. Unexpected crevice corrosion let to the exclusion of electrochemical data and restricted the opportunity of correlating the properties of the cover with the onset and rate of corrosion of reinforcement. The project did, however, provide valuable data on in situ strength, moisture content, permeability, resistivity, carbonation and rate of chloride ingress. Limited data is also available on the pore structure of the cover and its oxygen diffusion characteristics. It is emphasised that all results refer to uncracked concrete. (author).

  14. A study of Corrosion Protection of Aluminum Metal by Tetraethoxysilane Plasma Polymerized Coatings-Influence of Aluminum Surface Pretreatments-

    Institute of Scientific and Technical Information of China (English)

    YoshihiroMomose; TatsuyaYabuki

    2004-01-01

    The corrosion-protective performance of plasma-polymerized (PP) coatings on pretreated aluminum substrates has been investigated by cathodic polarization curve measurement. The surface composition and electronic properties of the pretreated and PP film coated metal surfaces were also characterized by XPS and the temperature-programmed photoelectron emission (TPPE). A PP coating was prepared on the pretreated surfaces by plasma polymerization of a mixture of tetraethoxysilane (TEOS) monomer vapor and oxygen using a 13.56MHz radiofrequency generator. The polarization curve of PP film coated samples was measured in NaC1 aqueous solution. The weight loss rate calculated from the value of the corrosion current of the curve was used to estimate the protective performance of the PP film coated samples. Argon plasma treatment of the metal surface gave much better corrosion-protective performance than pretreatments such as oxidation by heating in air and diamond scratching. The XPS analysis indicated that the silicon oxide assigned to SiO2 was formed on the PP film coated surface. The TPPE analysis revealed that the electron emission characteristics for the metal surfaces pretreated only were strongly influenced by the pretreatments, while all the PP film coated samples exhibited nearly the same electron emission trend with a much decreased intensity.

  15. A study of Corrosion Protection of Aluminum Metal by Tetraethoxysilane Plasma Polymerized Coatings -Influence of Aluminum Surface Pretreatments-

    Institute of Scientific and Technical Information of China (English)

    Yoshihiro Momose; Tatsuya Yabuki

    2004-01-01

    The corrosion-protective performance of plasma-polymerized (PP) coatings on pretreated aluminum substrates has been investigated by cathodic polarization curve measurement. The surface composition and electronic properties of the pretreated and PP film coated metal surfaces were also characterized by XPS and the temperature-programmed photoelectron emission (TPPE). A PP coating was prepared on the pretreated surfaces by plasma polymerization of a mixture of tetraethoxysilane (TEOS) monomer vapor and oxygen using a 13.56MHz radiofrequency generator. The polarization curve of PP film coated samples was measured in NaCl aqueous solution. The weight loss rate calculated from the value of the corrosion current of the curve was used to estimate the protective performance of the PP film coated samples. Argon plasma treatment of the metal surface gave much better corrosion-protective performance than pretreatments such as oxidation by heating in air and diamond scratching. The XPS analysis indicated that the silicon oxide assigned to SiO2 was formed on the PP film coated surface. The TPPE analysis revealed that the electron emission characteristics for the metal surfaces pretreated only were strongly influenced by the pretreatments, while all the PP film coated samples exhibited nearly the same electron emission trend with a much decreased intensity.

  16. Corrosion of rapidly solidified neodymium-iron-boron (Nd-Fe-B) permanent magnets and protection via sacrificial zinc coatings

    Energy Technology Data Exchange (ETDEWEB)

    Attanasio, S.A. [Massachusetts Inst. of Tech., Cambridge (United States). Dept. of Materials Science and Engineering; Latanision, R.M. [Massachusetts Inst. of Tech., Cambridge (United States). Dept. of Materials Science and Engineering

    1995-07-15

    Rapidly solidified Nd-Fe-B alloys were found to corrode actively at open circuit in aerated Na{sub 2}SO{sub 4} and NaCl at 30 C and 80 C. Estimated penetration rates (greater than 27 mil year{sup -1}) indicate the need for corrosion control methods.The use of sacrificial zinc coatings in controlling the corrosion of Nd-Fe-B alloys may have previously been overlooked because of two potential limitations: incomplete protection and hydrogen damage. The electrochemical activity of Nd may prevent zinc from providing complete sacrificial protection to Nd-Fe-B at breaks in the coating, and cracking could occur when hydrogen production is galvanically stimulated on Nd-Fe-B at breaks in the coating.This study focuses on the evaluation of the protection conferred to Nd-Fe-B when a Zn/Nd-Fe-B galvanic couple is formed due to coating penetration. Quantitative solution analysis was used to demonstrate that the dissolution of Nd, Fe and B is essentially prevented by the galvanic coupling of Nd-Fe-B to zinc in NaCl at 25 C. Galvanic coupling to zinc also reduces the rate of environmentally assisted cracking of Nd-Fe-B. Sacrificial zinc coatings appear to be a viable, cost-effective corrosion control method for Nd-Fe-B, and the limitations described above should not preclude their use in this application. (orig.)

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

    Science.gov (United States)

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

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

  18. INFLUENCE OF PHOSPHATIZED SURFACE LAYER ON CORROSION RESISTANCE OF Mg-Al-RE ALLOY

    Directory of Open Access Journals (Sweden)

    Katarína Miková

    2015-09-01

    Full Text Available This contribution deals with evaluation of the corrosion resistance of extruded Mg-2Al-1RE (AE21 magnesium alloy in the state before and after treatment of ground surface by selected phosphatizing procedure. Specimens were exposed to 0.1M NaCl solution for several time periods starting from 5 minutes up-to 168 hours at room temperature of 22 ± 1 °C. Afterwards electrochemical impedance spectroscopy was carried out on the exposed specimens. Based on the results obtained from the electrochemical tests and visual observation of corrosion attack progress, positive or negative impact of selected phosphating process on the corrosion resistance of Mg-2Al-1RE magnesium alloy under given conditions was assessed.

  19. Corrosion and protection of metals in the rural atmosphere of "El Pardo" Spain (PATINA / CYTED project

    Directory of Open Access Journals (Sweden)

    Simancas, J.

    2003-12-01

    Full Text Available Atmospheric corrosion tests of metallic and organic coatings on steel, zinc and aluminium have been conducted in "El Pardo" (Spain as part of the PATINA/CYTED project "Anticorrosive Protection of Metals in the Atmosphere". This is a rural atmosphere with the following ISO corrosivity categories: C2 (Fe, C2 (Zn, C3 (Cu and Cl (Al. Its average temperature and relative humidity is 13 °C and 62.8 %, respectively, and it has low SO2 and Cl- contents. Results of 42 months exposure are discussed. Atmospheric exposure tests were carried out for the following types of coatings: conventional paint coatings for steel and hot-dip galvanized steel (group 1, new painting technologies for steel and galvanized steel (group 2, zinc-base metallic coatings (group 3, aluminium-base metallic coatings (group 4, coatings on aluminium (group 5 and coil-coatings on steel, hot-dip galvanized steel and 55 % Al-Zn coated steel (group 6.

    Como parte del proyecto PATINA/CYTED "Protección anticorrosiva de metales en la atmósfera" se han llevado a cabo en la estación de ensayo de "El Pardo" (España, ensayos de corrosión atmosférica de recubrimientos metálicos y orgánicos sobre acero, zinc y aluminio. Se trata de una atmósfera rural según la clasificación ISO de grado de corrosividad: C2 (Fe, C2 (Zn, C3 (Cu y Cl (Al. La temperatura y humedad relativa media es de 13 °C y 62,8 %, respectivamente, y tiene bajos contenidos de SO2 y Cl-. Se discuten los resultados obtenidos después de 42 meses de exposición. Los ensayos de corrosión atmosférica se llevaron a cabo para tres tipos de recubrimientos: recubrimientos de pintura convencional sobre acero y acero zincado (grupo 1, nuevas tecnologías en pinturas para acero y acero galvanizado (grupo 2, recubrimientos metálicos base zinc (grupo 3, recubrimientos metálicos base aluminio (grupo 4, recubrimientos sobre aluminio (grupo 5 y recubrimientos de banda en continuo

  20. Pitting corrosion behaviour of built-up welds - Effects of welding layers and tarnish; Lochkorrosionsverhalten von Auftragschweissungen - Schweisslagen- und Oberflaecheneffekte

    Energy Technology Data Exchange (ETDEWEB)

    Heyn, A.; Schilling, K.; Boese, E.; Spieler, S.; Altendorf, S. [Otto-von-Guericke-Universitaet Magdeburg, IWW, PF 4120, 39016 Magdeburg (Germany); Burkert, A. [BAM, Berlin, Fachgruppe VII.3, Unter den Eichen 87, 12205 Berlin (Germany); Schultze, S. [LMPA Sachsen-Anhalt, Grosse Steinernetischstrasse 4, 39104 Magdeburg (Germany)

    2003-12-01

    The pitting corrosion resistance of nickel based deposition welds on a superduplex steel made by active-gas metal pulsed-arc welding was studied. Therefore the determination of the CPT (Critical Pitting Temperature) should be carried out corresponding to ASTM G 48 C. However an unexpectedly low resistance of the built-up welds also at multilayer order was noticed. After visual assessment of the examined specimens a significant effect of the surface condition was assumed. Because the CPT determination according to ASTM does not allow any statement about the corrosion process, this method was not suitable to characterize the corrosion system. For this reason a new method was applied to clarify the causes of the low corrosion resistance. This method determines the CPT with the help of the electrochemical current noise under the same conditions demanded in ASTM G 48 C. The temperature is increased continuously and the characteristic parameters of the system are recorded and evaluated objectively within short time. So it was possible to see the influence of the surface condition on the pitting corrosion behaviour of the examined specimens. The required parameters to the post-processing of the deposition welds were determined. The comparison of the results show that the surface tarnish formed after the shielded arc welding process influences the pitting corrosion resistance negatively. After its elimination the CPT could be determined in dependence of the welding layers. (Abstract Copyright [2003], Wiley Periodicals, Inc.) [German] Zur vergleichenden Einschaetzung der Lochkorrosionsbestaendigkeit von verschiedenen, mehrlagigen MAGp-auftraggeschweissten Nickelbasis-Schweissguetern auf einem Superduplexstahl wurden kritische Lochkorrosionstemperaturen (critical pitting temperature, CPT) nach ASTM G 48 C ermittelt. Es zeigte sich eine unerwartet niedrige Bestaendigkeit der Auftragschweissungen, als dessen Ursache ein unguenstiger Oberflaechenzustand angenommen wurde. Da die

  1. Simultaneous use and self-consistent analyses of μ-PIXE and μ-EBS for the characterization of corrosion layers grown on ancient coins

    Science.gov (United States)

    Cruz, J.; Corregidor, V.; Alves, L. C.

    2017-09-01

    The study of corrosion products in two XVI century coins through the simultaneous and self-consistent μ-PIXE and μ-EBS spectra analyses is presented in this work. The fitted spectra give consistent results, showing the feasibility of this approach to determine in a fast and non-destructive way the elemental composition and concentration depth profiles of the corrosion layers.


  2. The corrosion protection of AISI(TM) 1010 steel by organic and inorganic zinc-rich primers

    Science.gov (United States)

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

    1995-01-01

    The behavior of zinc-rich primer-coated AISI 1010 steel in 3.5-percent Na-Cl was investigated using electrochemical techniques. The alternating current (ac) method of electrochemical impedance spectroscopy (EIS), in the frequency range of 0.001 to 40,000 Hz, and the direct current (dc) method of polarization resistance (PR), were used to evaluate the characteristics of an organic, epoxy zinc-rich primer and an inorganic, ethyl silicate zinc-rich primer. A dc electromechanical galvanic corrosion test was also used to determine the corrosion current of each zinc-rich primer anode coupled to a 1010 steel cathode. Duration of the EIS/PR and galvanic testing was 21 days and 24 h, respectively. The galvanic test results demonstrated a very high current between the steel cathode and both zinc-rich primer anodes (38.8 and 135.2 microns A/sq cm for the organic and inorganic primers, respectively). The results of corrosion rate determinations demonstrated a much higher corrosion rate of the zinc in the inorganic primer than in the organic primer, due primarily to the higher porosity in the former. EIS equivalent circuit parameters confirmed this conclusion. Based on this investigation, the inorganic zinc-rich primer appears to provide superior galvanic protection and is recommended for additional study for application on solid rocket booster steel hardware.

  3. Comparison of mechanical and corrosion properties of graphene monolayer on Ti–Al–V and nanometric Nb{sub 2}O{sub 5} layer on Ti–Al–V alloy for dental implants applications

    Energy Technology Data Exchange (ETDEWEB)

    Kalisz, M., E-mail: malgorzata.kalisz@its.waw.pl [Motor Transport Institute, Jagiellońska 80, 03-301 Warsaw (Poland); Grobelny, M. [Motor Transport Institute, Jagiellońska 80, 03-301 Warsaw (Poland); Mazur, M. [Wroclaw University of Technology, Faculty of Microsystem Electronics and Photonics, Janiszewskiego 11/17, 50-372 Wroclaw (Poland); Zdrojek, M. [Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw (Poland); Wojcieszak, D. [Wroclaw University of Technology, Faculty of Microsystem Electronics and Photonics, Janiszewskiego 11/17, 50-372 Wroclaw (Poland); Świniarski, M.; Judek, J. [Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw (Poland); Kaczmarek, D. [Wroclaw University of Technology, Faculty of Microsystem Electronics and Photonics, Janiszewskiego 11/17, 50-372 Wroclaw (Poland)

    2015-08-31

    In this paper the comparative studies on structural, mechanical and corrosion properties of Nb{sub 2}O{sub 5}/Ti–Al–V and graphene/Ti–Al–V alloy systems have been investigated. We show that the hardness of pure niobium pentoxide was ca. 8.64 GPa and graphene deposited on titanium alloy surface was equal 5.63 GPa. However, the graphene monolayer has no effect on surface hardness of titanium alloy and can be easily removed from the surface. On the other hand, the sample with graphene coating has much better corrosion resistance. Our results suggest, that the use of combined layers of niobium pentoxide and graphene, in the hybrid multilayer system can greatly improve the mechanical and corrosion properties of the titanium alloy surface. Such hybrid system can be used in the future, as protection coating for Ti alloy, in biomedical application and in other applications, where Ti alloys work in an aggressive corrosive environment and in engineering applications where friction is involved. - Highlights: • Corrosion properties of Nb{sub 2}O{sub 5}/TiAlV and graphene/TiAlV systems were investigated. • Nb{sub 2}O{sub 5} thin film improves titanium alloy surface hardness from 5.64 GPa to 8.64 GPa. • Nb{sub 2}O{sub 5} thin film improves corrosion resistance of Ti{sub 6}Al{sub 4}V in aggressive environment. • i{sub corr} for graphene monolayer deposited on Ti{sub 6}Al{sub 4}V surface decreases to 0.01 μA/cm{sup 2}. • Graphene monolayer caused decrease in the electrochemical activity of the Ti surface.

  4. PROTECTIVE LAYERS OF IRON AND NICKEL ALUMINIDES ON STEEL

    Directory of Open Access Journals (Sweden)

    Milena Voderova

    2013-05-01

    Full Text Available Intermediary phases Ni-Al and Fe-Al are promising materials due to their superior properties such as hardness and good resistance against oxidation at high temperatures. Moreover, Fe-Al phases are resistant in sulphur - containing atmospheres. Because of these characteristics, the above mentioned intermetallic phases seem to be prospective for the use in many technical applications such as energetics, chemical or automotive industry in a form of a bulk material or coatings. Presently, the protective aluminide layer is usually prepared by thermal spraying. Nevertheless, this method is not suitable for complex-shaped components. Therefore, the aim of this work was to find an alternative way to prepare layers consisting of nickel or iron aluminides by other technique than thermal spraying. At first, carbon steel samples were coated using galvanic or electroless nickel plating. Coated samples were subsequently submerged into molten aluminium at various temperatures and process durations. The influence of the temperature and duration on the intermetallic phase growth was studied by scanning electron and light microscopy. Thickness and microhardness of the intermetallic layer was also measured.

  5. PROTECTIVE LAYERS OF IRON AND NICKEL ALUMINIDES ON STEEL

    Directory of Open Access Journals (Sweden)

    Milena Voděrová

    2013-07-01

    Full Text Available Intermediary phases Ni-Al and Fe-Al are promising materials due to their superior properties such as hardness and good resistance against oxidation at high temperatures. Moreover, Fe-Al phases are resistant in sulphur - containing atmospheres. Because of these characteristics, the above mentioned intermetallic phases seem to be prospective for the use in many technical applications such as energetics, chemical or automotive industry in a form of a bulk material or coatings. Presently, the protective aluminide layer is usually prepared by thermal spraying. Nevertheless, this method is not suitable for complex-shaped components. Therefore, the aim of this work was to find an alternative way to prepare layers consisting of nickel or iron aluminides by other technique than thermal spraying. At first, carbon steel samples were coated using galvanic or electroless nickel plating. Coated samples were subsequently submerged into molten aluminium at various temperatures and process durations. The influence of the temperature and duration on the intermetallic phase growth was studied by scanning electron and light microscopy. Thickness and microhardness of the intermetallic layer was also measured.

  6. Surface treatment and history-dependent corrosion in lead alloys

    Energy Technology Data Exchange (ETDEWEB)

    Li Ning [Los Alamos National Laboratory, Los Alamos, NM (United States)]. E-mail: ningli@lanl.gov; Zhang Jinsuo [Los Alamos National Laboratory, Los Alamos, NM (United States); Sencer, Bulent H. [Los Alamos National Laboratory, Los Alamos, NM (United States); Koury, Daniel [University of Nevada, Las Vegas, NV (United States)

    2006-06-23

    In oxygen-controlled lead and lead-bismuth eutectic (LBE), steel corrosion may be strongly history dependent. This is due to the competition between liquid metal dissolution corrosion and oxidation as a 'self-healing' protection barrier. Such effects can be observed from corrosion testing of a variety of surface-treated materials, such as cold working, shot peening, pre-oxidation, etc. Shot peening of austenitic steels produces surface-layer microstructural damages and grain compression, which could contribute to increased Cr migration to the surface and enhance the protection through an impervious oxide. Pre-oxidation under conditions different from operating ones may form more protective oxides, reduce oxygen and metal ion migration through the oxides, and achieve better protection for longer durations. Corrosion and oxidation modeling and analysis reveal the potential for significantly reducing long-term corrosion rates by initial and early-stage conditioning of steels for Pb/LBE services.

  7. Finding of Gray Points on the Surface of the Sn-Fe Alloy Layer and Its Effects on the Corrosion Resistance of the Alloy Layer

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    After removing tin coating of tinplates offered by some steel works, we discovered massive, highly disperse gray points outspreading along rolling direction on the surface of the alloy layer. Morphology of the alloy layer was observed by scanning electron microscope (SEM), and many cavities of the alloy layer were found out in the gray point. After analyzing the composition of the alloy layer, we found that content of Fe in the gray points was more than that in the normal alloy layer. Moreover, corrosion resistance of the alloy layer declines with increase of amount of gray points.In addition, the hot-humidity testing was carried out for some plates whose surface has many gray points. After 14 days, there were many rust points occurring in the edge of gray points and in the small gray points. The morphology of rust points was observed by atomic force microscope (AFM). The reason why rust points generated in the edge of gray points and in the small gray points was discussed.

  8. Synthesis of hybrid sol-gel coatings for corrosion protection of we54-ae magnesium alloy

    Science.gov (United States)

    Hernández-Barrios, C. A.; Duarte, N. Z.; Hernández, L. M.; Peña, D. Y.; Coy, A. E.; Viejo, F.

    2013-11-01

    The present work shows some preliminary results related to the synthesis, characterization and corrosion evaluation of different hybrid sol-gel coatings applied on the WE54-AE magnesium alloy attending to the two experimental variables, i.e. the precursors ratio and the aging time, which may affect the quality and the electrochemical properties of the coatings resultant. The experimental results confirmed that, under some specific experimental conditions, it was possible to obtain homogeneous and uniform, porous coatings with good corrosion resistance that also permit to accommodate corrosion inhibitors.

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

    DEFF Research Database (Denmark)

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

    2005-01-01

    laser surface melting on microstructure and corrosion behaviour of AISI 316L welds. Welding and laser treatment parameters were varied. General corrosion behaviour of the weld and laser treated surface was characterised using a gel visualization test. The local electrochemistry of the weld and laser...... treated surface was investigated using a novel micro electrochemical technique with a tip resolution of ~1 mm. Results show that hybrid laser welding of 316L has increased corrosion susceptibility probably as a result of grain boundary carbide formation. However a suitable post laser treatment could...

  10. A systematic multiscale modeling and experimental approach to protect grain boundaries in magnesium alloys from corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Horstemeyer, Mark R. [Mississippi State Univ., Mississippi State, MS (United States); Chaudhuri, Santanu [Univ. of Illinois, Urbana-Champaign, IL (United States)

    2015-09-30

    A multiscale modeling Internal State Variable (ISV) constitutive model was developed that captures the fundamental structure-property relationships. The macroscale ISV model used lower length scale simulations (Butler-Volmer and Electronics Structures results) in order to inform the ISVs at the macroscale. The chemomechanical ISV model was calibrated and validated from experiments with magnesium (Mg) alloys that were investigated under corrosive environments coupled with experimental electrochemical studies. Because the ISV chemomechanical model is physically based, it can be used for other material systems to predict corrosion behavior. As such, others can use the chemomechanical model for analyzing corrosion effects on their designs.

  11. Synergistic effect of polypyrrole-intercalated graphene for enhanced corrosion protection of aqueous coating in 3.5% NaCl solution.

    Science.gov (United States)

    Qiu, Shihui; Li, Wei; Zheng, Wenru; Zhao, Haichao; Wang, Liping

    2017-09-15

    Dispersion of graphene in water and incorporation of it into waterborne resin have been rarely researched and hardly achieved owing to its hydrophobicity. Furthermore, it has largely been reported that graphene with impermeability contributed to the improved anticorrosion property. Here we show that highly concentrated graphene aqueous solution up to 5 mg/mL can be obtained by synthesizing hydrophilic polypyrrole nanocolloids as intercalators and ultrasonic vibration. Based on the π-π interaction between polypyrrole and graphene, stacked graphene sheets are exfoliated to the thickness of 3~5 layers without increasing defects. The corrosion performance of coatings without and with polypyrrole and graphene is collected by potential and impedance measurements, Tafel curves and fitted pore resistance immersed in 3.5 wt % NaCl solution. It turns out that composite coating with 0.5 wt % graphene additive exhibits superior anticorrosive ability. And mechanism of intercalated graphene-based coating is interpreted as the synergistic protection of impermeable graphene sheets and self-healing polypyrrole and proved by the identification of corrosion products and scanning vibrating electrode technique.

  12. Bond Strength Degradation of Corrosive Reinforced Lightweight Concrete

    Institute of Scientific and Technical Information of China (English)

    CHEN Yueshun; LU Yiyan; LI Houxiang; ZENG Sanhai

    2007-01-01

    The influence of reinforced bar corrosion on the bond degradation in lightweight concrete was studied. Accelerated constant current corrosion tests were performed on lightweight reinforced concrete samples, and the influential factors, such as protective layer thickness, reinforced bar diameter and corrosive level were investigated. The constant current step method was used to measure the electric resistance of the concrete protective cover, which was used to characterize the corrosion level of the rebar. Experimental results indicated that the corrosive resistance increased with increasing the cover dimension and decreasing the reinforced bar diameter, and the rate of decrease in the specimen impedance after cracking depended on the cover dimension. A new medium was offered for the further research on the performance degradation of corrosion lightweight concrete.

  13. Biocompatibility and Corrosion Protection Behaviour of Hydroxyapatite Sol-Gel-Derived Coatings on Ti6Al4V Alloy

    Directory of Open Access Journals (Sweden)

    Amir A. El Hadad

    2017-01-01

    Full Text Available The aim of this work was to prepare hydroxyapatite coatings (HAp by a sol-gel method on Ti6Al4V alloy and to study the bioactivity, biocompatibility and corrosion protection behaviour of these coatings in presence of simulated body fluids (SBFs. Thermogravimetric/Differential Thermal Analyses (TG/DTA and X-ray Diffraction (XRD have been applied to obtain information about the phase transformations, mass loss, identification of the phases developed, crystallite size and degree of crystallinity of the obtained HAp powders. Fourier Transformer Infrared Spectroscopy (FTIR has been utilized for studying the functional groups of the prepared structures. The surface morphology of the resulting HAp coatings was studied by Scanning Electron Microscopy (SEM. The bioactivity was evaluated by soaking the HAp-coatings/Ti6Al4V system in Kokubo’s Simulated Body Fluid (SBF applying Inductively Coupled Plasma (ICP spectrometry. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT and Alamar blue cell viability assays were used to study the biocompatibility. Finally, the corrosion behaviour of HAp-coatings/Ti6Al4V system was researched by means of Electrochemical Impedance Spectroscopy (EIS. The obtained results showed that the prepared powders were nanocrystalline HAp with little deviations from that present in the human bone. All the prepared HAp coatings deposited on Ti6Al4V showed well-behaved biocompatibility, good bioactivity and corrosion protection properties.

  14. Incorporation of Fe3O4/CNTs nanocomposite in an epoxy coating for corrosion protection of carbon steel

    Science.gov (United States)

    Pham, Gia Vu; Truc Trinh, Anh; To, Thi Xuan Hang; Duong Nguyen, Thuy; Trang Nguyen, Thu; Hoan Nguyen, Xuan

    2014-09-01

    In this study Fe3O4/CNTs composite with magnetic property was prepared by attaching magnetic nanoparticles (Fe3O4) to carbon nanotubes (CNTs) by hydrothermal method. The obtained Fe3O4/CNTs composite was characterized by Fourier transform infrared (FTIR) spectroscopy, powder x-ray diffraction and transmission electron microscopy. The Fe3O4/CNTs composite was then incorporated into an epoxy coating at concentration of 3 wt%. Corrosion protection of epoxy coating containing Fe3O4/CNTs composite was evaluated by electrochemical impedance spectroscopy and adhesion measurement. The impedance measurements show that Fe3O4/CNTs composite enhanced the corrosion protection of epoxy coating. The corrosion resistance of the carbon steel coated by epoxy coating containing Fe3O4/CNTs composite was significantly higher than that of carbon steel coated by clear epoxy coating and epoxy coating containing CNTs. FE-SEM photographs of fracture surface of coatings showed good dispersion of Fe3O4/CNTs composite in the epoxy matrix.

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

    DEFF Research Database (Denmark)

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

    2005-01-01

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

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

    DEFF Research Database (Denmark)

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

    2005-01-01

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

  17. Partial disjoint path for multi-layer protection in GMPLS networks

    OpenAIRE

    Urra i Fàbregas, Anna; Calle Ortega, Eusebi; Marzo i Lázaro, Josep Lluís

    2005-01-01

    In this paper, different recovery methods applied at different network layers and time scales are used in order to enhance the network reliability. Each layer deploys its own fault management methods. However, current recovery methods are applied to only a specific layer. New protection schemes, based on the proposed partial disjoint path algorithm, are defined in order to avoid protection duplications in a multi-layer scenario. The new protection schemes also encompass shared segment backup ...

  18. Corrosion protection of SiC-based ceramics with CVD mullite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Auger, M.L.; Sarin, V.K. [Boston Univ., MA (United States). Dept. of Mfg. Engineering

    1997-12-01

    For the first time, crystalline mullite coatings have been chemically vapor deposited on SiC substrates to enhance its corrosion and oxidation resistance. Thermodynamic and kinetic considerations have been utilized to produce mullite coatings with a variety of growth rates, compositions, and morphologies. The flexibility of processing can be exploited to produce coated ceramics with properties tailored to specific applications and varied corrosive environments.

  19. Electrochemical corrosion behavior of steel wires in a coalmine with a corrosive medium

    Institute of Scientific and Technical Information of China (English)

    Wang Songquan; Zhang Dekun; Wang Dagang; Zhang Zefeng

    2011-01-01

    A 6 × 19 point-contact hoisting cable was used as our research object to examine the progress of corrosion of steel wires in a laboratory, simulating the actual working conditions in a coalmine. An electrochemical method was used to investigate the corrosion behavior of steel wires with different surface treatments of a corrosive acid solution. The results show that anode activation of steel wire mainly occurs during pre-corrosion, where the anode activation process of bare steel wires is the fastest as is their corresponding corrosion speed, while the anode activation process of oil coated steel wires and their corresponding corrosion speed are the lowest. During the intermediate and late immersion periods,a passive film is generated on the surface of steel wires, which are gradually damaged with the passage of time. Local pitting corrosion occurs easily on the surface of steel wires with a high-polarization potential.Suitable equivalent circuits were chosen to fit the electrochemical impedance spectroscopy (EIS) of steel wires over various corrosive times and different surface treatments, which indicate good fitting results.The double electrical layer charge-transfer resistance increases in the sequence: bare steel wire,untreated steel wire and oil coated steel wire and their corrosion resistance decreases in turn, which is consistent with their polarization curves. The oil layer provides a certain protective effect on untreated steel wires, but its effect is not entirely clear.

  20. Improved Corrosion Resistance and Mechanical Properties of CrN Hard Coatings with an Atomic Layer Deposited Al2O3 Interlayer.

    Science.gov (United States)

    Wan, Zhixin; Zhang, Teng Fei; Lee, Han-Bo-Ram; Yang, Ji Hoon; Choi, Woo Chang; Han, Byungchan; Kim, Kwang Ho; Kwon, Se-Hun

    2015-12-01

    A new approach was adopted to improve the corrosion resistance of CrN hard coatings by inserting a Al2O3 layer through atomic layer deposition. The influence of the addition of a Al2O3 interlayer, its thickness, and the position of its insertion on the microstructure, surface roughness, corrosion behavior, and mechanical properties of the coatings was investigated. The results indicated that addition of a dense atomic layer deposited Al2O3 interlayer led to a significant decrease in the average grain size and surface roughness and to greatly improved corrosion resistance and corrosion durability of CrN coatings while maintaining their mechanical properties. Increasing the thickness of the Al2O3 interlayer and altering its insertion position so that it was near the surface of the coating also resulted in superior performance of the coating. The mechanism of this effect can be explained by the dense Al2O3 interlayer acting as a good sealing layer that inhibits charge transfer, diffusion of corrosive substances, and dislocation motion.

  1. Graphene: corrosion-inhibiting coating.

    Science.gov (United States)

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

    2012-02-28

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

  2. Protective silicon coating for nanodiamonds using atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lu, J. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, Hebei 066004 (China); College of Materials Science and Engineering, Yanshan University, Qinhuangdao, Hebei 066004 (China); Wang, Y.H. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, Hebei 066004 (China); College of Materials Science and Engineering, Yanshan University, Qinhuangdao, Hebei 066004 (China); Zang, J.B. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, Hebei 066004 (China) and College of Materials Science and Engineering, Yanshan University, Qinhuangdao, Hebei 066004 (China)]. E-mail: diamondzjb@163.com; Li, Y.N. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, Hebei 066004 (China); College of Materials Science and Engineering, Yanshan University, Qinhuangdao, Hebei 066004 (China)

    2007-01-30

    Ultrathin silicon coating was deposited on nanodiamonds using atomic layer deposition (ALD) from gaseous monosilane (SiH{sub 4}). The coating was performed by sequential reaction of SiH{sub 4} saturated adsorption and in situ decomposition. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were utilized to investigate the structural and morphological properties of the coating. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to compare the thermal stability of nanodiamonds before and after silicon coating. The results confirmed that the deposited cubic phase silicon coating was even and continuous. The protective silicon coating could effectively improve the oxidation resistance of nanodiamonds in air flow, which facilitates the applications of nanodiamonds that are commonly hampered by their poor thermal stability.

  3. Corrosion behaviour and structure of the surface layer formed on austempered ductile iron in concentrated sulphuric acid

    Energy Technology Data Exchange (ETDEWEB)

    Krawiec, H. [AGH University of Science and Technology, Department of Foundry Engineering, ul. Reymonta 23, 30-059 Cracow (Poland)]. E-mail: krawiec@uci.agh.edu.pl; Stypula, B. [AGH University of Science and Technology, Department of Foundry Engineering, ul. Reymonta 23, 30-059 Cracow (Poland); Stoch, J. [Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences (PAS), ul. Niezapominajek 8, 30-239 Cracow (Poland); Mikolajczyk, M. [Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences (PAS), ul. Niezapominajek 8, 30-239 Cracow (Poland)

    2006-03-15

    The aim of this paper is to investigate the structure of the surface layer formed on austempered ductile iron (ADI) after exposure to hot concentrated sulphuric acid at the open circuit potential value (OCP). The results derived from polarization measurements carried out in sulphuric acid at a temperature of 90 deg. C show that anodic dissolution of ADI is divided into three stages (corresponding to three anodic dissolution peaks). The structure of the layer formed on alloys at 90 deg. C at OCP was investigated using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). SEM analysis shows that the main elements of the surface layer are iron, silicon, oxygen, sulphur, and carbon. The binding energy recorded in individual bands indicates that the surface layer includes mainly SiO{sub 2} and FeOOH. The presence of sulphur at the lower oxidation state (S{sup 2-}) indicates that sulphuric acid undergoes reduction during this process. The corrosion resistance of these alloys is connected with the presence of SiO{sub 2} in the surface layer.

  4. Corrosion control in mining technology

    Energy Technology Data Exchange (ETDEWEB)

    Telekesi, J.

    1985-01-01

    An overview of corrosion effects in mining technology and the importance of protection is presented. The most common corrosion processes and effects are summarized and the system and criteria of their avoidance are discussed in detail. Preventive measures are recommended to decrease possible corrosion effects including the selection of corrosion-resistive constructions, to use protective coatings and inhibition techniques and some other protection possibilities where applicable. The organization aspects and the economic impact of corrosion control in mining are discussed.

  5. Electron transport in molecular junctions with graphene as protecting layer

    Energy Technology Data Exchange (ETDEWEB)

    Hüser, Falco; Solomon, Gemma C., E-mail: gsolomon@nano.ku.dk [Nano-Science Center and Department of Chemistry, University of Copenhagen, 2100 København Ø (Denmark)

    2015-12-07

    We present ab initio transport calculations for molecular junctions that include graphene as a protecting layer between a single molecule and gold electrodes. This vertical setup has recently gained significant interest in experiment for the design of particularly stable and reproducible devices. We observe that the signals from the molecule in the electronic transmission are overlayed by the signatures of the graphene sheet, thus raising the need for a reinterpretation of the transmission. On the other hand, we see that our results are stable with respect to various defects in the graphene. For weakly physiosorbed molecules, no signs of interaction with the graphene are evident, so the transport properties are determined by offresonant tunnelling between the gold leads across an extended structure that includes the molecule itself and the additional graphene layer. Compared with pure gold electrodes, calculated conductances are about one order of magnitude lower due to the increased tunnelling distance. Relative differences upon changing the end group and the length of the molecule on the other hand, are similar.

  6. Silicon protected with atomic layer deposited TiO2

    DEFF Research Database (Denmark)

    Seger, Brian; Tilley, S. David; Pedersen, Thomas

    2013-01-01

    The present work demonstrates that tuning the donor density of protective TiO2 layers on a photocathode has dramatic consequences for electronic conduction through TiO2 with implications for the stabilization of oxidation-sensitive catalysts on the surface. Vacuum annealing at 400 °C for 1 hour...... of atomic layer deposited TiO2 increased the donor density from an as-deposited value of 1.3 × 1019 cm -3 to 2.2 × 1020 cm-3 following the annealing step. Using an Fe(ii)/Fe(iii) redox couple it was shown that the lower dopant density only allows electron transfer through TiO2 under conditions of weak band...... bending. However it was shown that increasing the dopant density to 2.2 × 1020 cm-3 allows tunneling through the surface region of TiO2 to occur at significant band bending. An important implication of this result is that the less doped material is unsuitable for electron transfer across the TiO2...

  7. 东莞东江大桥防腐涂装设计%Design of Corrosion Protection Coating for Dongguan Dongjiang River Bridge

    Institute of Scientific and Technical Information of China (English)

    傅战工; 徐恭义

    2011-01-01

    Dongguan Dongjiang River Bridge is a continuous steel truss girder bridge stiffened by rigid suspension members and the site where the bridge is located is in the severe corrosion environment. Through comparison of the performance indices of the epoxy zinc rich premier, alcohol-soluble inorganic silicate zinc rich premier, water-base inorganic silicate zinc rich premier and spraying metal that have been commonly used as the corrosion protection systems for the exterior surfaces of steel structure, in the light of the characteristics of the different structural parts of the bridge and also in comprehensive consideration of the durability, environmental protection, costsaving and maintainability, it was determined that the epoxy zinc rich coating system was to be used for the corrosion protection of the exterior surfaces and high-strength bolt heads of the main trusses, the water-base inorganic silicate zinc rich coating system for the stringers, cross beams and inspection trolley, the electric arc spraying aluminum for the frictional surfaces of the bolts,the light color modified epoxy asphalt for the interior surfaces ofthe box members, the galvanization layer and sealing paint for the steel crush barriers, the resin coating for the balustrades on the sidewalks and the hot-dipped galvanization for the drainage steel pipes of the bridge.%东莞东江大桥为刚性悬索加劲连续钢桁梁桥,桥位处于较严重的腐蚀环境.通过对环氧富锌底漆、醇溶性无机硅酸富锌底漆、水性无机硅酸富锌底漆和喷涂金属等钢结构外表面常用防腐体系的性能指标比较,针对不同结构部位的特点,综合考虑耐久性、环保性、经济性和可维护性,主桁外表面和螺栓头采用环氧富锌体系防腐;纵、横梁和检查车采用水性无机富锌体系防腐;高强螺栓摩擦面采用电弧喷铝防腐;箱形杆件内表面采用淡色改性环氧沥青漆防腐;钢防撞栏采用镀锌层加封闭漆防腐;人

  8. Synthesis and characterization of novel coatings for corrosion protection and hydrogen embrittlement inhibition

    Science.gov (United States)

    Durairajan, Anand

    The degradation of metallic materials under the effect of corrosion is a costly problem, which nearly every industry is confronted with. By using electrochemical plating, one can alter the characteristics of a surface so as to provide improved appearance, ability to withstand corrosive agents, resistance to abrasion, improved electrocatalytic properties or other desired properties or a combination of them. The primary goal of this dissertation is to use electrochemical deposition (electrolytic and electroless) as a surface modification technique to obtain corrosion resistant high performance electrode materials for different electrochemical applications. Metal hydride alloys, which reversibly absorb/desorb hydrogen, have been used in battery applications. The continuous decrease in the absorb/desorbing capacity of these alloys has been attributed to the corrosion of the alloy. Cobalt encapsulation (electroless) has been used as a surface modification method to obtain high performance AB5 type metal hydride alloy. The coated material has a higher capacity and longer cycle life compared to the bare alloy. Pulverization and alloy oxidation---two prime reasons for capacity fading of MH alloys have been studied in greater detail using unique electrochemical and physical characterization methods. The harmful effects of hydrogen permeation (ingress) and related stress corrosion cracking (SCC) can limit the use of metals and alloys in aqueous environments. In the present work, a new Zn-Ni-Cd plating process which offers a unique way of controlling and optimizing the Zn and Cd contents in the final deposit, has been developed. The Zn Ni-Cd alloy coatings has a more anodic corrosion potential than that of Cd but higher than the corrosion potential of iron. The coatings have superior corrosion resistance (10 times higher) and barrier properties than the conventional Cd coatings. Zn-Ni-Cd coatings also inhibit the hydrogen entry into the underlying steel. The kinetic

  9. Carbon corrosion of proton exchange membrane fuel cell catalyst layers studied by scanning transmission X-ray microscopy

    Science.gov (United States)

    Hitchcock, Adam P.; Berejnov, Viatcheslav; Lee, Vincent; West, Marcia; Colbow, Vesna; Dutta, Monica; Wessel, Silvia

    2014-11-01

    Scanning Transmission X-ray Microscopy (STXM) at the C 1s, F 1s and S 2p edges has been used to investigate degradation of proton exchange membrane fuel cell (PEM-FC) membrane electrode assemblies (MEA) subjected to accelerated testing protocols. Quantitative chemical maps of the catalyst, carbon support and ionomer in the cathode layer are reported for beginning-of-test (BOT), and end-of-test (EOT) samples for two types of carbon support, low surface area carbon (LSAC) and medium surface area carbon (MSAC), that were exposed to accelerated stress testing with upper potentials (UPL) of 1.0, 1.2, and 1.3 V. The results are compared in order to characterize catalyst layer degradation in terms of the amounts and spatial distributions of these species. Pt agglomeration, Pt migration and corrosion of the carbon support are all visualized, and contribute to differing degrees in these samples. It is found that there is formation of a distinct Pt-in-membrane (PTIM) band for all EOT samples. The cathode thickness shrinks due to loss of the carbon support for all MSAC samples that were exposed to the different upper potentials, but only for the most aggressive testing protocol for the LSAC support. The amount of ionomer per unit volume significantly increases indicating it is being concentrated in the cathode as the carbon corrosion takes place. S 2p spectra and mapping of the cathode catalyst layer indicates there are still sulfonate groups present, even in the most damaged material.

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

    Science.gov (United States)

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

    2016-08-01

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

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

    Science.gov (United States)

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

    2016-10-20

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

  12. Electrochemical deposition of Mg(OH2/GO composite films for corrosion protection of magnesium alloys

    Directory of Open Access Journals (Sweden)

    Fengxia Wu

    2015-09-01

    Full Text Available Mg(OH2/graphene oxide (GO composite film was electrochemical deposited on AZ91D magnesium alloys at constant potential. The characteristics of the Mg(OH2/GO composite film were investigated by scanning electron microscope (SEM, energy-dispersive X-ray spectrometry (EDS, X-ray diffractometer (XRD and Raman spectroscopy. It was shown that the flaky GO randomly distributed in the composite film. Compared with the Mg(OH2 film, the Mg(OH2/GO composite film exhibited more uniform and compact structure. Potentiodynamic polarization tests revealed that the Mg(OH2/GO composite film could significantly improve the corrosion resistance of Mg(OH2 film with an obvious positive shift of corrosion potential by 0.19 V and a dramatic reduction of corrosion current density by more than one order of magnitude.

  13. Evaluation of the mechanical and corrosion protection performance of electrodeposited hydroxyapatite on the high energy electron beam treated titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Gopi, D., E-mail: dhanaraj_gopi@yahoo.com [Department of Chemistry, Periyar University, Salem 636 011, Tamil Nadu (India); Centre for Nanoscience and Nanotechnology, Periyar University, Salem 636 011,Tamil Nadu (India); Sherif, El-Sayed M. [Center of Excellence for Research in Engineering Materials (CEREM), Advanced Manufacturing Institute, King Saud University, P.O. Box 800, Al-Riyadh 11421 (Saudi Arabia); Electrochemistry and Corrosion Laboratory, Department of Physical Chemistry, National Research Centre (NRC), Dokki, 12622 Cairo (Egypt); Rajeswari, D. [Department of Chemistry, Periyar University, Salem 636 011, Tamil Nadu (India); Department of Physics, Periyar University, Salem 636 011, Tamil Nadu (India); Kavitha, L. [Department of Physics, School of Basic and Applied Sciences, Central University of Tamil Nadu, Thiruvarur 610 101, Tamil Nadu (India); Pramod, R.; Dwivedi, Jishnu [Industrial Accelerator Section, Raja Ramanna Centre for Advanced Technology, Indore 452 013, Madhya Pradesh (India); Polaki, S.R. [Surface and Nanoscience Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India)

    2014-12-15

    Graphical abstract: - Highlights: • Ti–6Al–4V alloy was surface treated by high energy low current DC electron beam. • Successful electrodeposition of HAP was achieved on surface treated Ti–6Al–4V. • The as-formed coating possessed improved surface wettability and adhesion strength. • Maximum corrosion protection performance was exhibited by the as-formed coating. - Abstract: In our present study, the Ti–6Al–4V alloy surface was modified by irradiating with the high energy low current DC electron beam (HELCDEB) using 700 keV DC accelerator. Following this, the HELCDEB treated surface was coated with hydroxyapatite by adopting electrodeposition method. The microstructure and hardness of HELCDEB treated Ti–6A1–4V alloy with and without electrodeposited hydroxyapatite were investigated. Also, the electrochemical corrosion characteristics of the samples in simulated body fluid (SBF) was studied by potentiodynamic polarisation and electrochemical impedence techniques (EIS) which showed an enhanced corrosion resistance and revealed an improved life time for the hydroxyapatite coating developed on the HELCDEB treated Ti–6A1–4V alloy than the untreated sample.

  14. Organic coatings as corrosion protection in low-temperature boilers; Organische Beschichtungen als Korrosionsschutz in Niedertemperatur-Heizkesseln

    Energy Technology Data Exchange (ETDEWEB)

    Faller, M. [Eidgenoessische Materialpruefungs- und Versuchsanstalt fuer Industrie, Bauwesen und Gewerbe, Duebendorf (Switzerland)

    1995-03-15

    The feasibility of organic coatings as corrosion protection of low temperature boilers was investigated by laboratory and practical tests. Apart from good mechanical properties the coatings should also have a good stability against aggressive, sour corrosives and and a low permeability to water vapour. A two-component epoxy resin and various thermally hardening phenol resins were chosen as test coatings. The coating systems were analysed by measuring the coating thickness, the adhesion, the water permeability, the absence of porosity and the temperature resistance. The mechanical resistance was measured by abrasion and impact resistance. The corrosion resistance was tested by standardized laboratory tests: the atmospheric exposure in saturated water vapour with and without presence of sulphur dioxide and the salt-spray testing with sodium chloride. The chemical resistance against various concentrated sulphuric and hydrochloric acids was tested by immersion experiments. All examined systems had good to very good physical properties. They are thermally resistant to 150{sup o}C. The thermally hardening up to phenol resins had a much better chemical resistance than the two-component epoxy resin. The most promising coating system was applied to the heat exchange surfaces of a boiler and then tested in a continuous low temperature test of three months according to DIN 4702. The coating was not damaged and proved to be resistant to these conditions. (author) figs., tabs., 1 ref.

  15. Corrosion protection agents for the inner chambers of internal combustion engines. Schutzmittel zum Korrosionsschutz der Innenraeume von Verbrennungsmotoren

    Energy Technology Data Exchange (ETDEWEB)

    Ettig, A.; Ferke, M.; Fueloep, J.; Gal, L.; Gyoengyoessy, L.; Horvath, R.; Keresztessy, Z.; Keresztessy, M.; Papp, I.

    1987-09-17

    Subject of the invention are protective agents for corrosion prevention of the interior of internal combustion engines which contain: (a) 70 to 95 weight-% of a base oil and/or engine oil; (b) 0.1 to 6.0 weight-% of an additive from a detergent with neutralizing effect, (c) 0.05 to 2.0 weight-% of a barium salt, calcium or zink salt of dialkyl dithiophosphoric acids, (d) 1 to 12 weight-% of an anti-corrosion neutralizing inhibitor of a polyethylene glycol sulphonamide, polyethylene glycol - N-(alkyl)-sulphonamide, polyethylene glycol sulphonimide or poyethylene glycol - N-(alkyl)-sulphonimide and (e) 0.1 to 1.0 weight-% of a corrosion inhibitor and also emulsification inhibitor of a monoester, diester or triester of fatty acids with a double bond as well as possibly (f) 0.1 to 6.0 weight-% of an additive of a polyolefine or olefine copolymer and this additive shall increase the viscosity index and the adherence.

  16. QUANTUM-CHEMICAL MODIFICATIONS OF SURFACE:NEW METHODS FOR PROTECTING MATERIALS FROM CORROSION

    Institute of Scientific and Technical Information of China (English)

    R. T. Malkhasyan

    2001-01-01

    A new method of corrosion-resistant coating of technical iron is presented. Processingby vibrationally excited hydrogen molecules of the iron surface covered with oxide filmof a-Fe2O3 results in modification of surface by creating a film of amorphous ironon it. The presence of iron films with crystalline and amorphous phases, having thedifferent Fermi levels, leads tO formation of potential differences between them. Thispotential difference is opposite to the external electric field, resulting in decrease ofanode current and increase of corrosion resistance.

  17. Protection of NdFeB magnets by corrosion resistance phytic acid conversion film

    Science.gov (United States)

    Nan, Haiyang; Zhu, Liqun; Liu, Huicong; Li, Weiping

    2015-11-01

    Phytic acid conversion film was prepared on NdFeB magnets by dipping the NdFeB into phytic acid solution. The morphology, composition, structure and corrosion resistance of the film were systematically investigated. The results showed that the phytic acid film was effective in improving the corrosion resistance of NdFeB magnets. XRD, TEM and FT-IR analyses revealed that the film was amorphous and had a strong peak of phosphate radical (PO43-). The formation mechanism of the film was also explored by XPS and the potential of zero charge (Epzc) measurement at the solution-metal interface.

  18. Sputter-ion plating of coatings for protection of gas-turbine blades against high-temperature oxidation and corrosion

    Science.gov (United States)

    Coad, J. P.; Restall, J. E.

    1982-01-01

    Considerable effort is being devoted to the development of overlay coatings for protecting critical components such as turbine blades against high-temperature oxidation, corrosion, and erosion damage in service. The most commercially advanced methods for depositing coatings are electron-beam evaporation and plasma spraying. Sputter-ion plating (SIP) offers a potentially cheaper and simpler alternative method for depositing overlays. Experimental work on SIP of Co-Cr-Al-Y and Ni-Cr-Al-Ti alloy coatings is described. Results are presented of metallographic assessment of these coatings, and of the results obtained from high-velocity testing using a gas-turbine simulator rig.

  19. INFLUENCE OF PHOSPHATIZED SURFACE LAYER ON CORROSION RESISTANCE OF Mg-Al-RE ALLOY

    OpenAIRE

    Katarína Miková; Filip Pastorek; Libor Trško; Sylvia Dundeková

    2015-01-01

    This contribution deals with evaluation of the corrosion resistance of extruded Mg-2Al-1RE (AE21) magnesium alloy in the state before and after treatment of ground surface by selected phosphatizing procedure. Specimens were exposed to 0.1M NaCl solution for several time periods starting from 5 minutes up-to 168 hours at room temperature of 22 ± 1 °C. Afterwards electrochemical impedance spectroscopy was carried out on the exposed specimens. Based on the results obtained from the electroc...

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

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

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

  1. Modified Hydrotalcites as Smart Additives for Improved Corrosion Protection of Reinforced Concrete

    NARCIS (Netherlands)

    Yang, Z.

    2015-01-01

    Corrosion of reinforcing steel is a major culprit to durability and serviceability of concrete structures. This problem is highly relevant for civil engineering structures in the transport sector, such as bridges, tunnels, harbour quays and parking structures. The dominant aggressive external influe

  2. A simple device in a horizontal TG analyzer to prevent mixing of corrosive and protective gases

    NARCIS (Netherlands)

    Velde, van de G.M.H.; Longe, T.A.; Spitbergen, U.

    1982-01-01

    A ceramic cylinder has been developed as an accessory to a standard DuPont 951 Thermogravimetric Analyzer to study weight changes of solid samples in corrosive atmospheres. This device has two purposes to be fulfilled at higher temperatures (≤ 9OO°C) and higher gas flow rates (≤ 14 cm s-l): (1) prev

  3. Adhesive Bonding and Corrosion Protection of a Die Cast Magnesium Automotive Door

    Science.gov (United States)

    Bretz, G. T.; Lazarz, K. A.; Hill, D. J.; Blanchard, P. J.

    It is well known that magnesium alloys, in close proximity to other alloys, are susceptible to galvanic corrosion. Combined with this fact, in automotive applications, it is rare that magnesium will be present in the absence of other alloys such as steel or aluminum. Therefore, in wet applications, where the galvanic cell is completed, it is necessary to isolate the magnesium in order to prevent accelerated corrosion. There are numerous commercial pre-treatments available for magnesium, however this paper focuses on conversion coatings in conjunction with a spray powder coat. By means of example, results for a hem flange joint on an AM50 die cast magnesium door structure will be presented. The outer door skin is an aluminum alloy hemmed around a cast magnesium flange. An adhesive is used between the inner and outer to help with stiffness and NVH (Noise, Vibration and Harshness). Results from bonded lap-shear coupon tests that have been exposed to accelerated corrosion cycles are presented. A second phase of this work considered a surrogate hem flange coupon, which was similarly exposed to the same accelerated corrosion cycle. Results from both of these tests are presented within this paper along with a discussion as to their suitability for use within automotive applications.

  4. CE dual-homing protection in layer 1 VPN

    Science.gov (United States)

    Du, Shu; Peng, Yunfeng; Long, Keping

    2008-11-01

    Layer 1 VPN (L1VPN) extends the notion of VPN to the optical domain to provide virtually dedicated circuit like leased lines, so that the security is more enhanced. Despite their secure gains from channel isolation, VPNs still suffer fragilities resulting from link-failures or node-failures. Extensive activities on survivability designs for wavelength-routed optical networks are proposed, including various protection and restoration schemes, but concerns on network edge are rare. Dual-homing is an effective skill to achieve survivability gains for L1VPNs. There are two dual-homing mode: Active/Standby mode and Load-Sharing mode In this paper, we investigate the problem of PE assignment, which is the key of dual-homing design and is NP-hard. We formulate it as an integer programming problem, and propose heuristic solutions. Simulation results show that the proposed solutions work in a correct and effective way and the Load-Sharing mode has higher bandwidth efficiency than Active/Standby mode.

  5. Corrosion Mechanism of Buried Oil Pipelines and Protection%埋地油气管道腐蚀机理研究及防护

    Institute of Scientific and Technical Information of China (English)

    林新宇; 吴明; 程浩力; 龙世华; 王鹏

    2011-01-01

    埋地油气管道的腐蚀一直是油气储运及集输工程的一个重要问题.分析了埋地油气输送管道腐蚀的各种形式及主要腐蚀机理.针对输油管道的腐蚀问题,从土壤微生物、理化性质以及交流电对管道的腐蚀影响等方面进行了分析.介绍了埋地油气混输管道腐蚀防护的方法:加缓蚀剂、外涂层、内涂层和衬里保护、阴极保护法、杂散电流排流保护等.提出要提高油气输送管道的使用寿命,就应在合理选择防腐护方法的同时,加强防腐管道的维护和保养,这些是管道防腐工作的的重中之重.%The corrosion of buried oil and gas pipeline has always been a problem for oil and gas storage and transportation and oil-gas gathering. In this paper, main corrosion forms of buried pipelines and the corrosion mechamsm were analyzed. Then effects of soil microorganism, soil physical and chemical properties and alternating current on pipeline corrosion were also analyzed. Some methods of corrosion protection were introduced, such as adding inhibitor, external coating, internal coating and lining protection, cathodic protection, stray current protection and so on. To solve the corrosion problem, the methods of corrosion protection must be selected reasonably, and maintenance of the pipeline must be strengthened, which is the key work in pipeline anticorrosion.

  6. Corrosion Behavior of S450EW Low-alloy Weathering Steel in Cyclically Alternate Corrosion Environments

    Institute of Scientific and Technical Information of China (English)

    Jun-shan WANG; Pei-yang SHI; Cheng-jun LIU; Mao-fa JIANG

    2015-01-01

    Weathering steel is widely used in various ifelds due to its excellent mechanical properties and high corrosion resistance. The effect of chromium content on the S450EW weathering steel in cyclic immersion test was studied. The results indicated that the corrosion resistance of S450EW weathering steel is closely related to chromium content. The addition of chromium signiif-cantly inhibited the weathering steel corrosion. The corrosion rate of experimental steel after 96 h immersion was 1.101 g·m−2·h−1. The rust of S450EW weathering steel was mainly constituted of FeOOH and Fe3O4 phase, and the elevation of chromium content promoted the formation of α-FeOOH. The ifne precipitates of the two phases contributed to the formation of dense dust layer of test steel. Furthermore, the increase of chromium is beneifcial for the cure of original defects and cracks of the rust layer via the enrich-ment of chromium. The corrosion potential and the resistance of corrosion process were thus increased, protecting the experimental steel from further corrosion. A S450EW steel with corrosion resistance more than 1.5 times of Q450NQR1 steel was prepared.

  7. Protection by high velocity thermal spraying coatings on thick walled permanent and interim store components for the diminution of repairs, corrosion and costs 'SHARK'. Overview at the end of the project; Schutz durch Hochgeschwindigkeitsflammspritzschichten auf dickwandigen End- und Zwischenlagerbauteilen zur Reduktion von Reparaturen, Korrosion und Kosten 'SHARK'. Ein Ueberblick zum Abschluss des Projektes

    Energy Technology Data Exchange (ETDEWEB)

    Behrens, Sabine; Hassel, Thomas; Bach, Friedrich-Wilhelm [Unterwassertechnikum Hannover, Garbsen (Germany). Inst. fuer Werkstoffkunde; Steinwarz, Wolfgang; Dyllong, Nobert; Tragsdorf, Inga Maren [Siempelkamp Nukleartechnik GmbH, Krefeld (Germany)

    2012-04-15

    The corrosion protection of the internal space of thick-walled interim and permanent storage facility components, such as Castor {sup copyright} containers, are ensured nowadays by a galvanic nickel layer. The method has proved itself and protects the base material of the containers at the underwater loading in the Nuclear power station from a corrosive attack. Although, the galvanic nickel plating is a relatively time consuming method, it lasts for several days for each container, and is with a layer thickness of 1,000 {mu}m also expensive. To develop an alternative, faster and more economical method, a BMBF research project named - 'SHARK - protection by high velocity thermal spraying layers on thick-walled permanent and interim store components for the diminution of repairs, corrosion and costs' in cooperation between Siempelkamp Nukleartechnik GmbH and the Institute of Materials Science of the Leibniz University of Hanover was established to investigate the suitability of the high velocity oxy fuel spraying technology (HVOF) for the corrosion protective coating of thickwalled interim and permanent storage facility components. Since the permanent storage depot components are manufactured from cast iron with globular graphite, this material was exclusively used as a base material in this project. The evaluation of the economical features of the application of different nickel base spraying materials on cast iron substratum was in focus, as well as the scientific characterization of the coating systems with regard to the corrosion protective properties. Furthermore, the feasibility of the transfer of the laboratory results on a large industrial setup as well as a general suitability of the coating process for a required repair procedure was to be investigated. The preliminary examination program identified chromium containing spraying materials as successful. Results of the preliminary examination program have been used for investigations with the CASOIK

  8. Corrosion resistance of high-performance materials titanium, tantalum, zirconium

    CERN Document Server

    2012-01-01

    Corrosion resistance is the property of a material to resist corrosion attack in a particular aggressive environment. Although titanium, tantalum and zirconium are not noble metals, they are the best choice whenever high corrosion resistance is required. The exceptionally good corrosion resistance of these high–performance metals and their alloys results from the formation of a very stable, dense, highly adherent, and self–healing protective oxide film on the metal surface. This naturally occurring oxide layer prevents chemical attack of the underlying metal surface. This behavior also means, however, that high corrosion resistance can be expected only under neutral or oxidizing conditions. Under reducing conditions, a lower resistance must be reckoned with. Only very few inorganic and organic substances are able to attack titanium, tantalum or zirconium at ambient temperature. As the extraordinary corrosion resistance is coupled with an excellent formability and weldability these materials are very valua...

  9. Formation mechanism of the protective layer in a blast furnace hearth

    Science.gov (United States)

    Jiao, Ke-xin; Zhang, Jian-liang; Liu, Zheng-jian; Xu, Meng; Liu, Feng

    2015-10-01

    A variety of techniques, such as chemical analysis, scanning electron microscopy-energy dispersive spectroscopy, and X-ray diffraction, were applied to characterize the adhesion protective layer formed below the blast furnace taphole level when a certain amount of titanium- bearing burden was used. Samples of the protective layer were extracted to identify the chemical composition, phase assemblage, and distribution. Furthermore, the formation mechanism of the protective layer was determined after clarifying the source of each component. Finally, a technical strategy was proposed for achieving a stable protective layer in the hearth. The results show that the protective layer mainly exists in a bilayer form in the sidewall, namely, a titanium-bearing layer and a graphite layer. Both the layers contain the slag phase whose major crystalline phase is magnesium melilite (Ca2MgSi2O7) and the main source of the slag phase is coke ash. It is clearly determined that solid particles such as graphite, Ti(C,N) and MgAl2O4 play an important role in the formation of the protective layer, and the key factor for promoting the formation of a stable protective layer is reasonable control of the evolution behavior of coke.

  10. Formation mechanism of the protective layer in a blast furnace hearth

    Institute of Scientific and Technical Information of China (English)

    Ke-xin Jiao; Jian-liang Zhang; Zheng-jian Liu; Meng Xu; Feng Liu

    2015-01-01

    A variety of techniques, such as chemical analysis, scanning electron microscopy?energy dispersive spectroscopy, and X-ray dif-fraction, were applied to characterize the adhesion protective layer formed below the blast furnace taphole level when a certain amount of ti-tanium-bearing burden was used. Samples of the protective layer were extracted to identify the chemical composition, phase assemblage, and distribution. Furthermore, the formation mechanism of the protective layer was determined after clarifying the source of each component. Finally, a technical strategy was proposed for achieving a stable protective layer in the hearth. The results show that the protective layer mainly exists in a bilayer form in the sidewall, namely, a titanium-bearing layer and a graphite layer. Both the layers contain the slag phase whose major crystalline phase is magnesium melilite (Ca2MgSi2O7) and the main source of the slag phase is coke ash. It is clearly determined that solid particles such as graphite, Ti(C,N) and MgAl2O4 play an important role in the formation of the protective layer, and the key factor for promoting the formation of a stable protective layer is reasonable control of the evolution behavior of coke.

  11. Drum Screen Preventing Corrosion Protection and Common Issue Prevention%鼓形旋转滤网腐蚀防护及常见问题预防

    Institute of Scientific and Technical Information of China (English)

    孙宗旭; 黄海滨

    2015-01-01

    本文简要介绍了腐蚀的定义及腐蚀防护的基本方法,对鼓形旋转滤网腐蚀防护的难点及国内常见腐蚀防护方法的选择做了分析,并结合工程实践经验对鼓形旋转滤网腐蚀防护常见的问题进行了分析,提出了预防措施及解决办法,为工程施工过程提供参考依据。%This paper introduces the definition of corrosion and basic methods of corrosion protection. It analyzes the difficulties in corrosion protection of drum screen and the choice of common domestic corrosion protection method. According to engineering experience, common issues of corrosion protection of drum screen are also analyzed. It provides preventive measures and solutions for construction projects for reference.

  12. Other EPA Initiatives to Protect the Ozone Layer

    Science.gov (United States)

    Access information on EPA's efforts to address ozone layer depletion through voluntary partnerships with the private sector and activities aimed at educating the public about the health effects of ozone layer depletion.

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

    Science.gov (United States)

    Lei, Yanhua; Ohtsuka, Toshiaki; Sheng, Nan

    2015-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Maria Eliziane Pires de Souza

    2006-03-01

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

  15. Investigation of the weldability of iron-aluminum-chromium overlay coatings for corrosion protection in oxidizing/sulfidizing environments

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  17. Practical applications of ion beam and plasma processing for improving corrosion and wear protection

    CERN Document Server

    Klingenberg, M L; Wei, R; Demaret, J; Hirvonen, J

    2002-01-01

    A multi-year project for the US Army has been investigating the use of various ion beam and plasma-based surface treatments to improve the corrosion and wear properties of military hardware. These processes are intended to be complementary to, rather than competing with, other promising macro scale coating processes such high velocity oxy-fuel (HVOF) deposition, particularly in non-line-of- sight and flash chrome replacement applications. It is believed that these processes can improve the tribological and corrosion behavior of parts without significantly altering the dimensions of the part, thereby eliminating the need for further machining operations and reducing overall production costs. The ion beam processes chosen are relatively mature, low-cost processes that can be scaled-up. The key methods that have been considered under this program include nitrogen ion implantation into electroplated hard chrome, ion beam assisted chromium and chromium nitride coatings, and plasma-deposited diamond- like carbon an...

  18. Preparation of ultraviolet-cured nanocomposite coatings for protecting against corrosion of metal substrates

    Energy Technology Data Exchange (ETDEWEB)

    Malucelli, G.; Di Gianni, A. [Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, c. so Duca degli Abruzzi 24, 10129 Torino (Italy); Deflorian, F. [Dipartimento di Ingegneria dei Materiali e Tecnologie Industriali, Universita di Trento, Via Mesiano 77, 38050 Trento (Italy)], E-mail: defloria@ing.unitn.it; Fedel, M. [Dipartimento di Ingegneria dei Materiali e Tecnologie Industriali, Universita di Trento, Via Mesiano 77, 38050 Trento (Italy); Bongiovanni, R. [Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, c. so Duca degli Abruzzi 24, 10129 Torino (Italy)

    2009-08-15

    A cycloaliphatic di-epoxy monomer was used to prepare ultraviolet-cured coatings, in the presence of montmorillonites, either commercially available, or modified on purpose (Cloisite Na{sup +}, Cloisite 30B), dispersed at two different concentrations (5% and 10% w/w). The corrosion resistance of the ultraviolet-cured films coated on a metal substrate was investigated with electrochemical techniques and compared to the behaviour of the neat ultraviolet-cured epoxy resin films. The coatings showed different stability as revealed by the measurements of the barrier properties depending on the type of nanoclay used. Changing the modifier employed the coatings exhibited intercalated or exfoliated morphologies, as assessed by electron microscopy analysis and confirmed by X-ray diffraction results; the prevention of corrosion was proved dependent on the morphology.

  19. Oceanic corrosion test of bare and zinc-protected aluminum alloys for seawater heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Sasscer, D.S.; Ernst, R.; Morgan, T.O.; Rivera, C.; Scott, A.C.; Summerson, T.J.

    1984-01-01

    In a cooperative research effort between The Puerto Rico Center of Energy and Environment Research, Kaiser Aluminum and Chemical Corporation and The Trane Company, a six month study was made of the seawater corrosion performance of various aluminum materials to test their suitability for use in seawater heat exchangers. The materials tested included bare 3004 tubes, 7072 Alclad 3004 tubes and bare and zinc diffusion treated 3003 extrusions from a brazed aluminum, plate-fin heat exchanger extrusions from a brazed aluminium, plate-fin heat exchanger developed by The Trane Company. The test materials were exposed to 1.8 m/sec flowing seawater aboard an open ocean test facility moored 3.4 km off the southeast coast of Puerto Rico. After six months exposure, the average corrosion rates for most varieties of aluminum materials converged to a low value of 0.015 mm/yr (0.6 mils/yr).

  20. Corrosion Characteristics and Protection Techniques for Mg Alloys%镁合金的腐蚀特性及防护技术

    Institute of Scientific and Technical Information of China (English)

    高志恒

    2016-01-01

    ABSTRACT:Magnesium alloy is the lightest metallic structural material, and has broad application prospects in fields of automo-bile, 3C, national defence, aerospace and so on. However, the poor anti-corrosion property has become the bottleneck for its large-scale applications. The corrosion mechanisms of comprehensive corrosion, local corrosion and galvanic corrosion etc. of magnesium alloys as well as the factors affecting the corrosion resistance of magnesium alloy were elucidated in the paper. Based on the corro-sion resistance of magnesium alloy in different media, the three major factors affecting corrosion of magnesium alloys were intro-duced, and the two study directions to improve magnesium alloy′s corrosion resistance were summarized:one was to improve mag-nesium alloy′s intrinsic corrosion resistance, i. e. to improving the corrosion resistance of the material by optimization of alloy com-position and improving magnesium alloy′s microstructure. The other way was to use surface protection treatment technology, i. e. to separate the basis materials and the corrosion medium by using protective coatings to protect the basis materials. Then the methods to enhance the intrinsic corrosion resistance of magnesium alloy were reviewed, including purification of magnesium alloy′s compo-nents, inventing new kinds of anti-corrosion magnesium alloy, improving magnesium alloy′s surface microstructure, etc. The re-search status of organic polymerization and metallic compound corrosion resistant coatings for magnesium alloy were also summa-rized. Furthermore, the existing problems in the corrosion protection technologies of magnesium alloys and the future development orientation were pointed out.%镁合金作为最轻的金属结构材料,在汽车、3C、国防军工、航空航天等领域具有广阔的应用前景,但耐蚀性较差是其大规模应用的瓶颈。介绍了镁合金的腐蚀机理,包括全面腐蚀、局部腐蚀、电偶腐蚀等

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

    Science.gov (United States)

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

    2002-01-01

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

  2. The Effect of Powder Particle Biencapsulation with Ni-P Layer on Local Corrosion of Bonded Nd-(Fe,Co-B Magnetic Material

    Directory of Open Access Journals (Sweden)

    Klimecka-Tatar D.

    2015-04-01

    Full Text Available Effect of the Nd-(Fe,Co-B powder particle biencapsulation with Ni-P layer on bonded magnetic materials corrosion behaviour has been investigated. Bonded magnets were prepared from single-phase, nanocrystalline magnetic Nd11Fe77Co5B6 powder. Powder particles before consolidation were preliminary etched and then coated with bilayer (powder biencapsulation. The powder surface was coated as a first with autocatalytic applied Ni-P layer during 5, 15 and 30 minutes in Ni(II containing bath and the second layer was thermosetting epoxy-resin. Impact of the used biencapsulation process was rated on the basis of polarization curves recorded in phosphate environment with addition of chloric ions. It has been established that the used biencapsulation method satisfactorily isolate individual particles of the powder and consequently, significantly inhibits corrosion processes of the final material, especially in passivating environment containing Cl-.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  4. Graphene coating for anti-corrosion and the investigation of failure mechanism

    Science.gov (United States)

    Zhu, Y. X.; Duan, C. Y.; Liu, H. Y.; Chen, Y. F.; Wang, Y.

    2017-03-01

    Graphene produced by chemical vapor deposition (CVD) methods has been considered as a promising corrosion prevention layer because of its exceptional structure and impermeability. However, the anti-corrosion performance and the failure mechanism are still controversial. In this study, graphene layers with different quality levels, crystallite sizes, and layer numbers were prepared on the surface of Cu by a CVD process. The effects of grain boundaries (GBs) on the failure of graphene layers to provide adequate protection were investigated in detail by combining graphene transfer techniques, computation, and anti-corrosion measurements. Our results reveal that corrosion rates decrease marginally upon the increase of graphene layer number, and this rather weak dependence on thickness likely arises from the aligned nature of the GBs in CVD-grown few-layer graphene. This problem can potentially be overcome by layer-by-layer graphene transfer technique, in which corrosion is found to be arrested locally when transferred graphene is present on top of the as-grown graphene. However, this advantage is not reflected in corrosion studies performed on large-scale samples, where cracks or imperfect interfaces could offset the advantages of GB misalignment. With improvements in technology, the layer-by-layer assembly technique could be used to develop an effective anti-corrosion barrier.

  5. Triple-layer Absorptive Structures for Shock Wave Blast Protection

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Triple-layer absorptive structure is designed to reinforce a missile silo against shock wave blasts. An energy-absorbing layer and a cushion layer overlay the circular silo cover made of reinforced concrete. The dynamic stress analysis is performed by ABAQUS/Explicit. The mesoscopic structure of the energy absorbing layer is designed as an assembly of ductile tubes containing crushable cellular ceramics. Combined mesoscopic and macroscopic simulations indicate that the structure can enhance the survivability of a missile silo against blast waves.

  6. Effect of Temperature on the Corrosion Behavior of API X120 Pipeline Steel in H2S Environment

    Science.gov (United States)

    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.

  7. High performance corrosion and wear resistant composite titanium nitride layers produced on the AZ91D magnesium alloy by a hybrid method

    Directory of Open Access Journals (Sweden)

    Michał Tacikowski

    2014-09-01

    Full Text Available Composite, diffusive titanium nitride layers formed on a titanium and aluminum sub-layer were produced on the AZ91D magnesium alloy. The layers were obtained using a hybrid method which combined the PVD processes with the final sealing by a hydrothermal treatment. The microstructure, resistance to corrosion, mechanical damage, and frictional wear of the layers were examined. The properties of the AZ91D alloy covered with these layers were compared with those of the untreated alloy and of some engineering materials such as 316L stainless steel, 100Cr6 bearing steel, and the AZ91D alloy subjected to commercial anodizing. It has been found that the composite diffusive nitride layer produced on the AZ91D alloy and then sealed by the hydrothermal treatment ensures the corrosion resistance comparable with that of 316L stainless steel. The layers are characterized by higher electrochemical durability which is due to the surface being overbuilt with the titanium oxides formed, as shown by the XPS examinations, from titanium nitride during the hydrothermal treatment. The composite titanium nitride layers exhibit high resistance to mechanical damage and wear, including frictional wear which is comparable with that of 100Cr6 bearing steel. The performance properties of the AZ91D magnesium alloy covered with the composite titanium nitride coating are substantially superior to those of the alloy subjected to commercial anodizing which is the dominant technique employed in industrial practice.

  8. Mitigation of Corrosion on Magnesium Alloy by Predesigned Surface Corrosion

    OpenAIRE

    Xuming Zhang; Guosong Wu; Xiang Peng; Limin Li; Hongqing Feng; Biao Gao; Kaifu Huo; Chu, Paul K.

    2015-01-01

    Rapid corrosion of magnesium alloys is undesirable in structural and biomedical applications and a general way to control corrosion is to form a surface barrier layer isolating the bulk materials from the external environment. Herein, based on the insights gained from the anticorrosion behavior of corrosion products, a special way to mitigate aqueous corrosion is described. The concept is based on pre-corrosion by a hydrothermal treatment of Al-enriched Mg alloys in water. A uniform surface c...

  9. Composite coating with synergistic effect of biomimetic epoxy thermoset morphology and incorporated superhydrophobic silica for corrosion protection

    Directory of Open Access Journals (Sweden)

    W. F. Ji

    2016-11-01

    Full Text Available In this work, potential anticorrosive coating resulted from the composite with synergistic effect of biomimetic epoxy thermoset (BET morphology and incorporated superhydrophobic silica microspheres was presented. First of all, superhydrophobic methyl-modified silica (MS microspheres were synthesized by performing the conventional base-catalyzed sol-gel process of MTMS and APTMS. The as-prepared MS microspheres were identified as having an average particle size of ~1 µm in diameter. The as-prepared MS microspheres were characterized by Fourier transform infrared spectrometry (FTIR, 29Si and 13C solid-state nuclear magnetic resonance (NMR spectroscopy. Morphological properties of MS microspheres and BET-silica composite coating were studied by scanning electron microscopy (SEM. Subsequently, 3 wt% of MS microspheres were incorporated into an epoxy slurry of DGEBA/T-403 in dimetyl acetamide (DMAc, followed by performing the programmed heating through nanocasting technique with PDMS as soft template materials for pattern transfer by using leaf of Xanthosoma Sagittifolium as natural template, leading to the formation of artificial biomimetic composite coating. The appearance/dispersion capability of silica microspheres in BET coating was confirmed by the energy dispersive X-ray spectroscopy (EDX and Si-mapping. The roughness level of BET and BEC-3% were detected by AFM. The BETsilica composite was found to exhibit a contact angle (CA of ~153°, revealing the synergistic effect of biomimetic epoxy morphology and incorporated superhydrophobic MS microspheres, which is found to be more hydrophobic than that of neat epoxy thermoset (CA = 81°. Corrosion protection of as-prepared coatings was demonstrated by performing a series of electrochemical measurements (Tafel, Nyquists and Bode plots upon CRS electrodes in saline condition. It should be noted that the BET coatings upon CRS electrode revealed an effectively enhanced corrosion protection as compared

  10. Evaluation results on the effectiveness of the corrosion protection system for underground pipelines, using the DC-voltage gradient technique

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Antonio Carlos [Petroquimica Uniao S.A., Santo Andre, SP (Brazil)

    2003-07-01

    A pipeline of diameter 6'' with 17.694 km of extension was evaluated how much to the integrity of its external covering and the effectiveness of the system of cathodic protection, using the method DC-Voltage Gradient. The Cathodic Protection in this pipeline is made by seven rectifiers. The gotten data indicate that the potential pipe-ground registered in some check points to the long one of the pipeline is extremely negative, what has led to a super protection of the pipeline for the CP. This if explains for the great proximity between the anodes and the pipeline. For km had been identified 917 failures with a mean density of 50,1 per Km. Beyond the analysis of the data, this work includes conclusions and recommendations detailed for the repairs of the covering of the pipeline and for improvement of the effectiveness of the CP. One sends regards to a combination of repairs in the covering and reevaluation of the CP, in way to improve the protection level and to assure the reduction of the risk of external corrosion. (author)

  11. A synergistic combination of tetraethylorthosilicate and multiphosphonic acid offers excellent corrosion protection to AA1100 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Dalmoro, Viviane [Instituto de Química, Universidade Federal do Rio Grande do Sul (UFRGS) Av. Bento Gonçalves 9500 - CEP 91501-970, Porto Alegre, RS (Brazil); Departament d’Enginyeria Química, ETSEIB, Universitat Politècnica de Catalunya (UPC), Avda. Diagonal 647, Barcelona E-08028 (Spain); Center for Research in Nano-Engineering (CRnE), Universitat Politècnica de Catalunya (UPC), Campus Sud, Edifici C’, C/Pasqual i Vila s/n, Barcelona E-08028 (Spain); Santos, João H.Z. dos [Instituto de Química, Universidade Federal do Rio Grande do Sul (UFRGS) Av. Bento Gonçalves 9500 - CEP 91501-970, Porto Alegre, RS (Brazil); Armelin, Elaine, E-mail: elaine.armelin@upc.edu [Departament d’Enginyeria Química, ETSEIB, Universitat Politècnica de Catalunya (UPC), Avda. Diagonal 647, Barcelona E-08028 (Spain); Center for Research in Nano-Engineering (CRnE), Universitat Politècnica de Catalunya (UPC), Campus Sud, Edifici C’, C/Pasqual i Vila s/n, Barcelona E-08028 (Spain); Alemán, Carlos, E-mail: carlos.aleman@upc.edu [Departament d’Enginyeria Química, ETSEIB, Universitat Politècnica de Catalunya (UPC), Avda. Diagonal 647, Barcelona E-08028 (Spain); Center for Research in Nano-Engineering (CRnE), Universitat Politècnica de Catalunya (UPC), Campus Sud, Edifici C’, C/Pasqual i Vila s/n, Barcelona E-08028 (Spain); and others

    2013-05-15

    This work describes a new mechanism for the incorporation of organophosphonic acid into silane self-assembly monolayers, which has been used to protect AA1100 aluminum alloy. The protection improvement has been attributed to the fact that phosphonic structures promote the formation of strongly bonded and densely packed monolayer films, which show higher surface coverage and better adhesion than conventional silane systems. In order to evaluate the linking chemistry offered by phosphonic groups, two functionalized organophosphonic groups have been employed, 1,2-diaminoethanetetrakis methylenephosphonic acid (EDTPO) and aminotrimethylenephosphonic acid (ATMP), and combined with tetraethylorthosilicate (TEOS) films prepared by sol–gel synthesis. Results suggest that phosphonic acids may interact with the surface through a monodentate and bidentate coordination mode and, in addition, form one or more strong and stable linkages with silicon through non-hydrolysable bonds. Therefore, the incorporation of a very low concentration of phosphonic acids on TEOS solutions favors the complete coverage of the aluminum substrate during the silanization process, which is not possible using TEOS alone. The linking capacity of phosphonic acid has been investigated by FTIR-RA spectroscopy, SEM and EDX analysis, X-ray photoelectron spectroscopy (XPS), and quantum mechanical calculations. Finally, electrochemical impedance spectroscopy has been used to study the corrosion protection revealing that EDTPO-containing films afforded more protection to the AA1100 substrate than ATMP-containing films.

  12. A synergistic combination of tetraethylorthosilicate and multiphosphonic acid offers excellent corrosion protection to AA1100 aluminum alloy

    Science.gov (United States)

    Dalmoro, Viviane; dos Santos, João H. Z.; Armelin, Elaine; Alemán, Carlos; Azambuja, Denise S.

    2013-05-01

    This work describes a new mechanism for the incorporation of organophosphonic acid into silane self-assembly monolayers, which has been used to protect AA1100 aluminum alloy. The protection improvement has been attributed to the fact that phosphonic structures promote the formation of strongly bonded and densely packed monolayer films, which show higher surface coverage and better adhesion than conventional silane systems. In order to evaluate the linking chemistry offered by phosphonic groups, two functionalized organophosphonic groups have been employed, 1,2-diaminoethanetetrakis methylenephosphonic acid (EDTPO) and aminotrimethylenephosphonic acid (ATMP), and combined with tetraethylorthosilicate (TEOS) films prepared by sol-gel synthesis. Results suggest that phosphonic acids may interact with the surface through a monodentate and bidentate coordination mode and, in addition, form one or more strong and stable linkages with silicon through non-hydrolysable bonds. Therefore, the incorporation of a very low concentration of phosphonic acids on TEOS solutions favors the complete coverage of the aluminum substrate during the silanization process, which is not possible using TEOS alone. The linking capacity of phosphonic acid has been investigated by FTIR-RA spectroscopy, SEM and EDX analysis, X-ray photoelectron spectroscopy (XPS), and quantum mechanical calculations. Finally, electrochemical impedance spectroscopy has been used to study the corrosion protection revealing that EDTPO-containing films afforded more protection to the AA1100 substrate than ATMP-containing films.

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

    Institute of Scientific and Technical Information of China (English)

    PENG Tianlan; MAN Ruilin

    2009-01-01

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

  14. Electrochemical corrosion studies

    Science.gov (United States)

    Knockemus, W. W.

    1986-01-01

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

  15. Corrosion Protection and Design Improvement of an Aircraft%某型飞机腐蚀防护及设计改进

    Institute of Scientific and Technical Information of China (English)

    彭志军; 王学强; 叶彬

    2014-01-01

    Objective To study the corrosion problem of a certain aircraft, and to formulate structure corrosion repairing and anti-corrosion measures. Methods The corrosion reasons and the defects of the structure protection system were ob-tained after statistical analysis of aircraft corrosion classification and combing of the existing aircraft protection system. On the basis of aircraft serving area environment measurement, the aircraft ground parking environmental spectrum and the lo-cal environmental spectrum were developed. The design improvement measures for the structure protection system were taken, and the improvement effect of the design was verified by the accelerated corrosion test. Results Compared to the o-riginal state before improvement of the structure design, the calendar life of the anti-corrosion improvement structure was extend by 1. 6 to 5 times. Conclusion The aircraft was easy to subject to a variety of types of corrosion problems under the weak protection system. Good effect could only be achieved through systematic treatment of the problems in aircraft struc-ture corrosion.%目的:针对某型飞机的腐蚀问题开展研究,制定结构腐蚀修理和防腐改进措施。方法对外场飞机的腐蚀情况进行统计归类,对现有飞机防护体系进行梳理,分析结构腐蚀原因和防护体系的不足。在对飞机服役地区环境进行实测的基础上,编制飞机地面停放环境谱和飞机结构局部环境谱。研究制定结构防护体系设计改进措施,并通过加速腐蚀试验验证设计改进效果。结果与结构设计改进前的原始状态相比,防腐改进后的结构日历寿命提高1.6~5倍。结论飞机防护体系薄弱的情况下容易引发多种类型的腐蚀问题;系统地对飞机结构腐蚀问题进行治理,才能取得令人满意的效果。

  16. 埋地输油管道防腐技术的研究现状%Progress of Pipeline Corrosion Protection in soil

    Institute of Scientific and Technical Information of China (English)

    舒炼; 李晓敏; 胡苏

    2015-01-01

    The domestic and foreign oil pipeline that buried in earth, and the current status of research about the anti-corrosion methods, which suffered soil corrosion and caused serious accidents, were mainly discussed. based on the investigation of current exposition of antisepsis methods, soil corrosion effect and problems of controlling corrosion were elaborated, different conditions were analyzed, and the corresponding anti-corrosion measures was put forward. The buried soil pipeline according to the actual environment should have maximum protection by protective coating, corrosion inhibitor, electrochemical protection, cathode protection, and so on.%主要探讨了国内外输油管道在埋地铺设后,遭受土壤腐蚀而引起的严重事故及目前防腐方法的研究现状。本文在目前防腐方法调研的基础上阐述了土壤腐蚀影响、控制问题、腐蚀措施等方面,分析了不同情况下的影响因素,并提出了相应的防腐措施。对于埋地土壤中输油管道应根据实际铺设环境应采取涂层保护、缓蚀剂保护、电化学保护、阴极保护等手段因地制宜相结合,使输油管线得到最大的保护。

  17. Surface characterization and corrosion behavior of calcium phosphate-base composite layer on titanium and its alloys via plasma electrolytic oxidation: A review paper.

    Science.gov (United States)

    Rafieerad, A R; Ashra, M R; Mahmoodian, R; Bushroa, A R

    2015-12-01

    In recent years, calcium phosphate-base composites, such as hydroxyapatite (HA) and carbonate apatite (CA) have been considered desirable and biocompatible coating layers in clinical and biomedical applications such as implants because of the high resistance of the composites. This review focuses on the effects of voltage, time and electrolytes on a calcium phosphate-base composite layer in case of pure titanium and other biomedical grade titanium alloys via the plasma electrolytic oxidation (PEO) method. Remarkably, these parameters changed the structure, morphology, pH, thickness and crystallinity of the obtained coating for various engineering and biomedical applications. Hence, the structured layer caused improvement of the biocompatibility, corrosion resistance and assignment of extra benefits for Osseo integration. The fabricated layer with a thickness range of 10 to 20 μm was evaluated for physical, chemical, mechanical and tribological characteristics via XRD, FESEM, EDS, EIS and corrosion analysis respectively, to determine the effects of the applied parameters and various electrolytes on morphology and phase transition. Moreover, it was observed that during PEO, the concentration of calcium, phosphor and titanium shifts upward, which leads to an enhanced bioactivity by altering the thickness. The results confirm that the crystallinity, thickness and contents of composite layer can be changed by applying thermal treatments. The corrosion behavior was investigated via the potentiodynamic polarization test in a body-simulated environment. Here, the optimum corrosion resistance was obtained for the coating process condition at 500 V for 15 min in Ringer solution. This review has been summarized, aiming at the further development of PEO by producing more adequate titanium-base implants along with desired mechanical and biomedical features.

  18. Protection of carbon steel against hot corrosion using thermal spray Si- and Cr-base coatings

    Science.gov (United States)

    Porcayo-Calderon, J.; Gonzalez-Rodriguez, J. G.; Martinez, L.

    1998-02-01

    A Fe75Si thermal spray coating was applied on the surface of a plain carbon steel baffle plate. Beneath this coating, a Ni20Cr coating was applied to give better adherence to the silicon coating. The baffle was installed in the high-temperature, fireside, corrosion zone of a steam generator. At the same time, an uncoated 304 stainless steel baffle was installed nearby for comparison. For 13 months the boiler burned heavy fuel oil with high contents of vanadium. The samples were studied employing scanning electron microscopy, x-ray microanalysis, and x-ray diffraction techniques. After that, it was possible to inspect the structural state of the components, and it was found that the stainless steel baffle plates were destroyed almost completely by corrosion, whereas the carbon steel coated baffle plate did not suffer a significant attack, showing that the performance of the thermal spray coating was outstanding and that the coating was not attacked by vanadium salts of the molten slag.

  19. Cathodic corrosion protection for the inside areas of metallic plants (KKS-I); Kathodischer Korrosionsschutz fuer die Innenflaechen von metallischen Anlagen (KKS-I)

    Energy Technology Data Exchange (ETDEWEB)

    Tenzer, Norbert [TZ-International Corrosion Consulting, Hagen (Germany)

    2012-07-01

    Cathodic corrosion protection for the inside areas of metallic plants (KKS-I) is a worldwide used technology in order to afford a safe protection of metallic plans against corrosion. This technology is used for plants in the treatment and storage of drinking water, for containers and reaction vessels in the chemical industry, for plants in the oil and gas industry as well as for containers and large-dimension pipelines containing seawater for the cooling of air liquefaction plants, power plants and seawater desalination plants, for examples. Furthermore, there exist further special applications for wastewater systems and biogas plants. The general description of the KKS-I shall supply the information to the operators of appropriate plants, that the cathodic corrosion protection also offers a wide range of applications for the protection of the inside areas of the plants against corrosion. Beside the previously mentioned standard areas of application there exist manifold further possibilities of application for metallic plants. It has to be emphasized that there are application possibilities not only for unalloyed or low alloy steels but also for stainless steels, aluminium, lead, copper, titanium and zinc. The regulation DIN EN 12499 firstly edited in 2003 contains the fundamentals, areas of application and specifications.

  20. Multi-layer protective armour for underwater shock wave mitigation

    Directory of Open Access Journals (Sweden)

    Ahmed Hawass

    2015-12-01

    The strain gauge data and displacement sensors results showed that the multi-layer plates have higher level of underwater shock wave mitigation than the triple aluminum plates with strain and deflection of nearly 50%.

  1. 污水管道腐蚀机理及防护措施%Corrosion Mechanism and Protection Measures of Oilfield Sewage Pipelines

    Institute of Scientific and Technical Information of China (English)

    杨娜; 吴明; 齐浩; 王丹; 谢飞

    2013-01-01

    The corrosion mechanism of oil field sewage pipelines was analyzed. Types, conditions and characteristics of internal and external corrosion of pipelines were investigated. The main factors to cause the corrosion of sewage pipeline were listed;the impact of these factors was analyzed. According to the domestic and foreign research results on pipeline corrosion and research situation, some protection measures were proposed, such as using the coatings, electrochemical protection, using nonmetal pipelines, adding corrosion inhibitors and so on.%  分析了油田污水管道腐蚀机理,分别考察了管道外腐蚀和内腐蚀的类型、条件及特点。列举了造成污水管道腐蚀的主要影响因素,具体分析了这些因素的影响情况。根据国内外对管道腐蚀的研究结果及研究状况,提出了采用涂层、电化学保护、应用非金属管道及添加缓蚀剂等预防措施。

  2. 油套管腐蚀与防护技术发展现状%Current Status of Casing/Tubing Corrosion and Protection Technology

    Institute of Scientific and Technical Information of China (English)

    王军; 毕宗岳; 张劲楠; 王燕; 李超; 白鹤; 何石磊; 王涛

    2013-01-01

    介绍了国内外油套管腐蚀与防护的研究现状,分析了油气田开发过程中溶解气体腐蚀、细菌腐蚀、溶解盐腐蚀和温度、pH值及流速对油套管腐蚀的影响,探讨了国内外耐蚀合金、表面涂镀层、阴极保护及加注缓蚀剂等防腐技术的特点及其在油气开采中的应用.最后指出,油气井腐蚀环境不尽相同,每种防腐技术都有其使用条件的局限性,应该建立完善的并下监测系统,准确分析油气井管柱服役环境,针对不同的油气开采环境,选择适当的措施进行综合防护.%The current status of casing/tubing corrosion and protection at home and abroad were introduced.The influence of dissloved gas corrosion,bacterial corrosion,dissolving salt corrosion and temperature,PH value and flow velocity on casing/tubing corrosion were analyzed during oil and gas field development course,and the characteristics of corrosion resistant alloy,surface coating,cathodic protection and injecting corrosion inhibitor,as well as their application,were discussed.In the end,it pointed that the corrosion environment of oil well is not completely same with that of gas well,the service conditions of each corrosion resistance technology has its limitation.It should establish perfect underground monitoring system,accurately analyze service environment of oil and gas well tubularstring,and should select appropriate measures to conduct comprehensive protection for different oil and gas exploitation environment.

  3. Initial corrosion behaviors of AZ91 magnesium alloy in the presence of SO2

    Institute of Scientific and Technical Information of China (English)

    Cui Lin; Xiaogang Li

    2004-01-01

    The effects of SO2 on the initial atmospheric corrosion of AZ91D magnesium alloy were investigated in laboratory. Metallographic observation, SEM (Scanning Electron Microscopy), XRD (X-ray Diffraction) and XPS (X-ray Proton Spectrograph) were used to analyze and discuss the initial surface morphology of corrosion layers and corrosion products. The corrosion rate of the alloy increases with increasing the content of SO2. The initial attack has the characteristics of localized corrosion and preferentially concentrates on α phase. MgO and Mg(OH)2 form at first, which provide a protective layer, then the existence of SO2 decreases the pH of the thin solution on the alloy, accelerates dissolution process, and promotes the formation of MgSO3·6H20 and MgSO4·6H20,meanwhile cracks were found on the corrosion products with corrosion continuation. These soluble corrosion products and the cracks provide the paths for filtering oxygen and corrosion pollutants into the matrix, which results in severe localized corrosion and the loss of protective function of film.

  4. Corrosion Protection of Electro-Galvanized Steel by Green Conversion Coatings

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A cerium-based chemical conversion process was studied. First, zinc coating obtained from a free-cyanide alkaline bath, with derivative of imidazol with new brightener, was investigated, zinc-plated steel specimens were treated with a solution of 50 mmol·L-1 Ce(NO3)3. The corrosion behavior of bare and treated mild galvanized steel was evaluated during exposure to 0.5 mol·L-1 NaCl for different immersion time, using Tafel polarization curves and electrochemical impedance spectroscopy (EIS) measurements. The surface morphology of the coating was studied using scanning electron microscopy (SEM). The composition and chemical percent of the coating were examined by X-ray dispersion energy (EDAX). The results of these measurements showed that the newly developed cerium-based conversion coating process was a promising candidate for replacing the conventional chromate treatments used at present for galvanized steel.

  5. Limpets counteract ocean acidification induced shell corrosion by thickening of aragonitic shell layers

    Directory of Open Access Journals (Sweden)

    G. Langer

    2014-08-01

    Full Text Available Specimens of the patellogastropod limpet Patella caerulea were collected within (pHlow-shells and outside (pHn-shells a CO2 vent site at Ischia, Italy. Four pHlow-shells and four pHn-shells were sectioned transversally and scanned for polymorph distribution by means of confocal Raman microscopy. The pHlow-shells displayed a twofold increase in aragonite area fraction and size normalised aragonite area. Size normalised calcite area was halved in pHlow-shells. Taken together with the increased apical and the decreased flank size normalised thickness of the pHlow-shells, these data led us to conclude that low pH exposed P. caerulea specimens counteract shell dissolution by enhanced shell production. The latter is different from normal elongation growth and proceeds through addition of aragonitic layers only, while the production of calcitic layers is confined to elongation growth. Therefore aragonite cannot be regarded as a per se disadvantageous polymorph under ocean acidification conditions.

  6. Crystalline TiO2: A Generic and Effective Electron-Conducting Protection Layer for Photoanodes and -cathodes

    DEFF Research Database (Denmark)

    Mei, Bastian Timo; Pedersen, Thomas; Malacrida, Paolo;

    2015-01-01

    Stabilizing efficient photoabsorbers for solar water splitting has recently shown significant progress with the development of various protection layers. Suitable protection layers for tandem devices should be conductive, transparent, and stable in strongly acidic or alkaline solutions. This paper...

  7. Corrosion inhibitors and other protective systems in concrete repair concepts or misconcepts

    Institute of Scientific and Technical Information of China (English)

    XuKe

    2009-01-01

    The paper concludes that as long as one continues to blindly use protection methods applicable for newly constructed structures for concrete repairs,the business of "repairing the repairs"will be on the rise.A broader understanding of the electrochemical differences between new and repaired concrete is necessary for effective protection of reinforcement in repaired structures.

  8. Highly Stable Nanocontainer of APTES-Anchored Layered Titanate Nanosheet for Reliable Protection/Recovery of Nucleic Acid

    Science.gov (United States)

    Kim, Tae Woo; Kim, In Young; Park, Dae-Hwan; Choy, Jin-Ho; Hwang, Seong-Ju

    2016-02-01

    A universal technology for the encapsulative protection of unstable anionic species by highly stable layered metal oxide has been developed via the surface modification of a metal oxide nanosheet. The surface anchoring of (3-aminopropyl)triethoxysilane (APTES) on exfoliated titanate nanosheet yields a novel cationic metal oxide nanosheet, which can be universally used for the hybridization with various biological and inorganic anions. The encapsulation of deoxyribonucleic acid (DNA) in the cationic APTES-anchored titanate lattice makes possible the reliable long-term protection of DNA against enzymatic, chemical, and UV-vis light corrosions. The encapsulated DNA can be easily released from the titanate lattice via sonication, underscoring the functionality of the cationic APTES-anchored titanate nanosheet as a stable nanocontainer for DNA. The APTES-anchored titanate nanosheet can be also used as an efficient CO2 adsorbent and a versatile host material for various inorganic anions like polyoxometalates, leading to the synthesis of novel intercalative nanohybrids with unexplored properties and useful functionalities.

  9. DECORATIVE SANDWICH CONCRETES WITH A PROTECTIVE POLYMER LAYER ENSURING IMPROVED FRACTURE STRENGTH

    Directory of Open Access Journals (Sweden)

    Moiseenko Ksenija Sergeevna

    2012-10-01

    Pre-set theoretical provisions were applied to develop recommendations aimed at the optimization of the composition and characteristics of the technology of production of double-layer decorative and protective products based on polymer and mineral binders.

  10. Microstructures and properties of low-chromium high corrosion-resistant TiC-VC reinforced Fe-based laser cladding layer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hui; Zou, Yong, E-mail: yzou@sdu.edu.cn; Zou, Zengda; Wu, Dongting

    2015-02-15

    Highlights: • The cladding layer with 3.0%Cr and 0.25%CeO{sub 2} showed a good corrosion resistance. • Passive film formed on the cladding layer without Cr and CeO{sub 2} was Fe{sub 3}O{sub 4}. • Fe{sub 3}O{sub 4} displayed p type semiconductivity. • Passive film formed on the cladding layer with Cr and CeO{sub 2} was Fe(OH){sub 3} and Cr(OH){sub 3}. • Fe(OH){sub 3} displayed n type while Cr(OH){sub 3} displayed p type semiconductivity. - Abstract: Effects of 3.0 wt.%Cr and/or 0.25 wt.%CeO{sub 2} on microstructures and properties of TiC-VC reinforced Fe-based cladding layer were investigated by using X-ray diffractometry (XRD), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). Passive films formed on cladding layers surface were investigated by using X-ray photoelectron spectroscopy (XPS) and Mott-Schottky analysis. Results showed that phases of cladding layers were α-Fe, γ-Fe, TiC, VC and TiVC{sub 2}. There were no obvious effects of adding 3.0 wt.%Cr and/or 0.25 wt.%CeO{sub 2} on cladding layers phases. The microstructure of the cladding layer with 3.0 wt.%Cr and 0.25 wt.%CeO{sub 2} was lath martensite and retained austenite. Microhardness of the cladding layer with 0.25 wt.%CeO{sub 2} decreased slightly. Microhardness and corrosion resistance of the cladding layer with 3.0 wt.%Cr and 0.25 wt.%CeO{sub 2} both increased, the corrosion resistance increased 7.33 times while the EIS Nyquist spectrum transformed into a capacitive arc. The passive film formed on the cladding layer without Cr and CeO{sub 2} was Fe{sub 3}O{sub 4} which displayed p type semiconductivity. The passive film formed on the cladding layer with 3.0 wt.%Cr and 0.25 wt.%CeO{sub 2} was composed of Fe(OH){sub 3} and Cr(OH){sub 3}, which displayed n and p type semiconductivity respectively.

  11. The Corrosion and Protection of Circulating Water Pump in Nuclear Power Plant%核电厂循环水泵腐蚀与防护

    Institute of Scientific and Technical Information of China (English)

    李伟光; 赵万祥; 王佳栋; 孔全兴

    2014-01-01

    It Was simple analysed Based on the corrosion events of the circulating water pump occurring in some nuclear power plant, summarized the main corrosion types, and it was given relevant suggestion of corrosion and protection , it was provided the necessary technical and services support of the circulating pump maintenance for the subsequent serviced and refomed.%通过对某核电厂循环水泵出现的腐蚀事件进行简单的分析,总结其主要的腐蚀类型,并给出腐蚀与防护相关建议,为后续循环水泵维修和改造提供必要的技术和服务支持。

  12. Functional Requirements and Layers of Protection for Compounds

    NARCIS (Netherlands)

    Oosterhout, A.W.G. van; Wevers, J.

    2010-01-01

    The compounds that are used during out-of-area operations serve a host of goals of which protection is one. They should be approached as integrated systems that are designed (and upgraded) according to the rules that also apply for other systems. The design of a compound contains two distinctive

  13. An analysis on the effect of mining height and floor lithology on pressure relief of upper protective layers

    Institute of Scientific and Technical Information of China (English)

    Xu-chao HUANG; Dong-ling SUN; Kang-wu FENG

    2013-01-01

    In order to understand the effect of mining height and floor lithology at the upper protective layer face on the pressure relief of protected coal seams,this paper uses a numerical simulation method to model the pressure changes at protected coal seam during mining upper protective layer.The results show that the taller the mining height at the upper protective layer face,the greater the protection on protected coal seam due to the higher level of pressure release; the upper protective layer face with hard rock floor impedes the pressure release at the protected coal seam,which affects the overall effect of the pressure release at protected coal seam using the protective layer mining method.

  14. Graphene-protected iron layer on Ni(111)

    Energy Technology Data Exchange (ETDEWEB)

    Dedkov, Yuriy [FHI, Berlin (Germany); Fonin, Mikhail; Ruediger, Ulrich [Uni, Konstanz (Germany); Laubschat, Clemens [TU, Dresden (Germany)

    2009-07-01

    Magnetic thin films with out-of-plane (or perpendicular) magnetic anisotropy play an important role in nanotechnology. Such systems can be used as perpendicular recording media which are predicted to allow information storage densities of up to 1 Tbit/in.{sup 2} a quadrupling of today's highest areal densities. Along with the widely used materials with out-of-plane magnetic anisotropy such as CoPt or FePt alloys, face-centered cubic (fcc) Fe thin films also showing perpendicular magnetic anisotropy have recently attracted considerable interest as possible candidates for applications in novel magnetic data storage devices. Here Fe which originally has body centered cubic (bcc) structure can be stabilized in {gamma} phase (fcc) at room temperature in thin epitaxial films grown on suitable fcc substrates. Here we report a photoemission study of the Fe intercalation underneath a graphene layer on Ni(111). The process of intercalation was monitored by means of x-ray photoemission of corresponding core levels as well as ultraviolet photoemission of the graphene-derived {pi} states in the valence band. Thin fcc Fe layers (2-5 ML thickness) at the interface between a graphene capping layer and Ni(111) form epitaxial films passivated from the reactive environment.

  15. In-plane and through-plane non-uniform carbon corrosion of polymer electrolyte fuel cell cathode catalyst layer during extended potential cycles

    Science.gov (United States)

    Ghosh, Sourov; Ohashi, Hidenori; Tabata, Hiroshi; Hashimasa, Yoshiyuki; Yamaguchi, Takeo

    2017-09-01

    The impact of electrochemical carbon corrosion via potential cycling durability tests mimicking start-stop operation events on the microstructure of the cathode catalyst layer in polymer electrolyte fuel cells (PEFCs) is investigated using focused ion beam (FIB) fabrication without/with the pore-filling technique and subsequent scanning electron microscope (SEM) observations. FIB/SEM investigations without pore-filling reveals that the durability test induces non-uniform cathode shrinking across the in-plane direction; the thickness of the catalyst layer decreases more under the gas flow channel compared to the area under the rim of the flow field. Furthermore, FIB/SEM investigations with the pore-filling technique reveal that the durability test also induces non-uniform cathode shrinking in the through-plane direction; the pores in the area close to the membrane are more shrunken compared with those close to the microporous layer. In particular, a thin area (1-1.5 μm) close to the membrane is found to be severely damaged; it includes closed pores that hinder mass transport through the catalyst layer. It is suggested that uneven carbon corrosion and catalyst layer compaction are responsible for the performance loss during potential cycling operation of PEFCs.

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

    Directory of Open Access Journals (Sweden)

    Florica Simescu and Hassane Idrissi

    2008-01-01

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

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

    Science.gov (United States)

    Simescu, Florica; Idrissi, Hassane

    2008-12-01

    We outline the ability of zinc phosphate coatings, obtained by chemical conversion, to protect mild steel rebars against localized corrosion, generated by chloride ions in alkaline media. The corrosion resistance of coated steel, in comparison with uncoated rebars and coated and uncoated steel rebars embedded in mortar, were evaluated by open-circuit potential, potentiodynamic polarization, cronoamperometry and electrochemical impedance spectroscopy. The coated surfaces were characterized by x-ray diffraction and scanning electron microscopy. First, coated mild steel rebars were studied in an alkaline solution with and without chloride simulating a concrete pore solution. The results showed that the slow dissolution of the coating generates hydroxyapatite Ca10(PO4)6(OH)2. After a long immersion, the coating became dense and provided an effective corrosion resistance compared with the mild steel rebar. Secondly, the coated and uncoated steel rebars embedded in mortar and immersed in chloride solution showed no corrosion or deterioration of the coated steel. Corrosion rate is considerably lowered by this phosphate coating.

  18. Comparison Between the Inhibition Efficiencies of Two Modification Processes with PEG-Ceria Based Layers Against Corrosion of Mild Steel in Chloride and Sulfate Media

    Science.gov (United States)

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

    2017-08-01

    Cerium (III) and polyethylene glycol (PEG) combinations were employed to enhance the corrosion resistance of ASTM A915 mild steel in 0.1 M NaCl and in 0.1 M Na2SO4 media. One of the combinations consisted in dipping the steel in a bath mixture of PEG and cerium nitrate for 60 min. In the second combination, the steel was first immersed in the PEG solution for 30 min, then in cerium nitrate for 30 additional minutes. The corrosion protective capabilities of the superficially modified steels were evaluated through cyclic voltammetry, linear polarization resistance (R p), polarization measurements (Tafel) and electrochemical impedance spectroscopy. The composition and structure of the surface products were analyzed through Raman spectroscopy and scanning electron microscopy coupled to chemical EDS analysis. The mixture of PEG and cerium nitrate hindered the development of corrosion products on the mild steel surface. However, the subsequent immersion of the steel first in PEG then in cerium nitrate was not efficient to slow down corrosion.

  19. Protection against corrosion to high temperature by means of rich silicon coatings; Proteccion contra corrosion a alta temperatura por medio de recubrimientos ricos en silicio

    Energy Technology Data Exchange (ETDEWEB)

    Porcayo Calderon, Jesus [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    1999-07-01

    In this research work the study of the process of corrosion by molten salts of sodium sulphate-vanadium pentoxide and its prevention by means of metallic coatings rich in silicon was contemplated. The research encompassed the development of the coating system, the chemical and thermochemical analysis of the system sodium sulphate - vanadium pentoxide, the evaluation of the resistance to the corrosion of the coating system by gravimetric and electrochemistry techniques, and the study of the stability of the coating system - substrate. [Spanish] En este trabajo de investigacion se contempla el estudio del proceso de corrosion por sales fundidas de sulfato de sodio - pentoxido de vanadio y su prevencion por medio de recubrimientos metalicos ricos en silicio. La investigacion abarca el desarrollo del sistema de recubrimientos, el analisis quimico y termoquimico del sistema sulfato de sodio - pentoxido de vanadio, la evaluacion de la resistencia a la corrosion del sistema de recubrimientos por tecnicas gravimetricas y electroquimicas, y el estudio de la estabilidad del sistema recubrimiento - sustrato.

  20. Protecting nickel with graphene spin-filtering membranes: A single layer is enough

    Energy Technology Data Exchange (ETDEWEB)

    Martin, M.-B.; Dlubak, B.; Piquemal-Banci, M.; Collin, S.; Petroff, F.; Anane, A.; Fert, A.; Seneor, P. [Unité Mixte de Physique CNRS/Thales, 1 Avenue Augustin Fresnel, 91767 Palaiseau, France and Université Paris Sud, 91405 Orsay (France); Weatherup, R. S.; Hofmann, S.; Robertson, J. [Department of Engineering, University of Cambridge, Cambridge CB21PZ (United Kingdom); Yang, H. [IBS Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Blume, R. [Helmholtz-Zentrum Berlin fur Materialien und Energie, 12489 Berlin (Germany); Schloegl, R. [Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin (Germany)

    2015-07-06

    We report on the demonstration of ferromagnetic spin injectors for spintronics which are protected against oxidation through passivation by a single layer of graphene. The graphene monolayer is directly grown by catalytic chemical vapor deposition on pre-patterned nickel electrodes. X-ray photoelectron spectroscopy reveals that even with its monoatomic thickness, monolayer graphene still efficiently protects spin sources against oxidation in ambient air. The resulting single layer passivated electrodes are integrated into spin valves and demonstrated to act as spin polarizers. Strikingly, the atom-thick graphene layer is shown to be sufficient to induce a characteristic spin filtering effect evidenced through the sign reversal of the measured magnetoresistance.

  1. Protected Sulfur Cathode with Mixed Conductive Coating Layer for Lithium Sulfur Battery

    Science.gov (United States)

    Jin, Jun; Wen, Zhaoyin; Wang, Qingsong; Gu, Sui; Huang, Xiao; Chen, Chunhua

    2016-10-01

    A mixed conductive coating layer composed of lithium ion conductive ceramic powder, carbon and binder was introduced on the surface of a sulfur electrode. This coating layer is designed to suppress the migration of lithium polysulfides from the sulfur electrode, and improve the cycling capacity of a lithium sulfur battery. The protected sulfur cathode with a mixed conductive coating layer delivered an initial specific capacity of 1236 mAh g-1 at 0.5C and maintained a capacity of 842 mAh g-1 after 100 cycles. In particular, a soft package battery with protected cathode exhibits improved cycling capacity and excellent rate performance.

  2. The study on the influence of surface cleanness and water soluble salt on corrosion protection of epoxy resin coated carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Shon, Younng Shon [Pukyong National University, Busan (Korea, Republic of)

    2014-10-15

    The corrosion resistance of epoxy-coated carbon steel was evaluated. The carbon steel surface was subjected to different treatment methods such as steel grit blasting and power tool treatment as well as contamination of water soluble salt. To study the effect of the surface treatments and contamination, the topology of the treated surface was observed by confocal microscopy and a pull-off adhesion test was conducted. The corrosion resistance of the epoxy-coated carbon steel was further examined by electrochemical impedance spectroscopy (EIS) combined with immersion test of 3.5 wt% of NaCl solution. Consequently, the surface contamination by sodium chloride with 16 mg/m{sup 2}, 48 mg/m{sup 2} and 96 mg/m{sup 2} didn't affect the adhesion strength for current epoxy coated carbon steel and blister and rust were not observed on the surface of epoxy coating contaminated by various concentration of sodium chloride after 20 weeks of immersion in 3.5 wt% NaCl aqueous solutions. In addition, the results of EIS test showed that the epoxy-coated carbon steel treated with steel grit blasting and power tool showed similar corrosion protection performance and surface cleanness such as Sa 3 and Sa 2.5 didn't affect the corrosion protectiveness of epoxy coated carbon steel.

  3. Aviation Fuel Pipeline Buried Corrosion and Protection%航空燃料埋地输送管道的腐蚀与防护

    Institute of Scientific and Technical Information of China (English)

    秦一峰

    2012-01-01

    随着航空事业的发展,管输方式成为航空燃料又一广泛运用的运输方式,但腐蚀穿孔成为埋地管道的重要安全隐患。文章从腐蚀的分类分析了航空燃料埋地输送管道腐蚀的原因、影响因素,并重点从外防腐涂层和阴极保护两方面论述了当前对管道腐蚀防护的技术。%With the development of aviation,aviation fuel pipeline has become a widely used means of transport,but the corrosion of buried pipeline safety become important.In the paper the classification of corrosion analysis of aviation fuel buried pipeline corrosion,influencing factors,and from the point of external anticorrosive coating and cathodic protection are discussed in two aspects of the pipeline corrosion protection technology.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-03-15

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

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

    Directory of Open Access Journals (Sweden)

    Premjith Jayakumar Ramakrishnan

    2014-01-01

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

  6. Metal Surface Modification for Obtaining Nano- and Sub-Nanostructured Protective Layers

    Science.gov (United States)

    Ledovskykh, Volodymyr; Vyshnevska, Yuliya; Brazhnyk, Igor; Levchenko, Sergiy

    2017-03-01

    Regularities of the phase protective layer formation in multicomponent systems involving inhibitors with different mechanism of protective action have been investigated. It was shown that optimization of the composition of the inhibition mixture allows to obtain higher protective efficiency owing to improved microstructure of the phase layer. It was found that mechanism of the film formation in the presence of NaNO2-PHMG is due to deposition of slightly soluble PHMG-Fe complexes on the metal surface. On the basis of the proposed mechanism, the advanced surface engineering methods for obtaining nanoscaled and sub-nanostructured functional coatings may be developed.

  7. Thin film corrosion. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Raut, M.K.

    1980-06-01

    Corrosion of chromium/gold (Cr/Au) thin films during photolithography, prebond etching, and cleaning was evaluated. Vapors of chromium etchant, tantalum nitride etchant, and especially gold etchant were found to corrosively attack chromium/gold films. A palladium metal barrier between the gold and chromium layers was found to reduce the corrosion from gold etchant.

  8. Corrosion resistant PEM fuel cell

    Science.gov (United States)

    Fronk, Matthew Howard; Borup, Rodney Lynn; Hulett, Jay S.; Brady, Brian K.; Cunningham, Kevin M.

    2002-01-01

    A PEM fuel cell having electrical contact elements comprising a corrosion-susceptible substrate metal coated with an electrically conductive, corrosion-resistant polymer containing a plurality of electrically conductive, corrosion-resistant filler particles. The substrate may have an oxidizable metal first layer (e.g., stainless steel) underlying the polymer coating.

  9. The corrosion resistance and neutron-absorbing properties of coatings based on amorphous alloys

    Science.gov (United States)

    Sevryukov, O. N.; Polyansky, A. A.

    2016-04-01

    The object of the present study was the corrosion-resistant amorphizing alloys with an increased content of boron for cladding the surface of metals, rapidly quenched alloys without boron for protective coatings on a high-boron cladding layer, as well as steel samples with a protective coating with a high content of boron and without boron. The aim of the work is to investigate the corrosion resistance of a coating in water at the temperature of 40 °C in conditions of an open access of oxygen for 1000 h, as well as the features of the microstructure of clad samples before and after the corrosion tests. New data on the corrosion resistance of Cr18Ni10Ti steel samples with a protective layer from a rapidly quenched alloy Ni-19Cr-10Si (in wt.%) on a high-boron coating have been obtained.

  10. 钢质原油储罐的腐蚀与防护%Corrosion and Protection of Steel Crude Oil Tanks

    Institute of Scientific and Technical Information of China (English)

    李军龙; 徐星; 金刘伟; 巩毅超; 陈挺

    2016-01-01

    With the continuous development of petroleum and petrochemical industry, and increasing of oil storage capacity, more and more storage tanks are being applied. Because the physical and chemical properties of crude oil are relatively complex and crude oil has strong corrosive, research on oil tank anti-corrosion measures and methods is very important. In this paper, based on the status of the corrosion of crude oil tank, in order to improve the service life of the tank and reduce the incidence of the tank, the corrosion mechanism of each part of the tank was researched. At the same time, the concrete corrosion protection measures were put forward. Finally, key causes to affect the tank anti-corrosion effect were analyzed.%随着石油石化行业的快速发展,对原油的储存提出了更高的要求,这就需要新建大量的原油储罐。基于原油的理化性质相对复杂又具有极强的腐蚀性,因此,研究原油储罐防腐蚀的举措和方法受到高度的重视。针对原油储罐的腐蚀现状,为确保大型储罐安全长周期运行,解决储罐防腐技术应用中的腐蚀泄露问题,降低储罐的事故风险,分析了针对储罐各个部位的腐蚀机理所采取的防腐蚀措施。最后阐述了影响储罐防腐蚀效果的原因。

  11. Real-time corrosion control system for cathodic protection of buried pipes for nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Tae; Kim, Hae Woong; Kim, Young Sik [School of Materials Science and Engineering, Andong National University, Andong (Korea, Republic of); Chang, Hyun Young; Lim, Bu Taek; Park, Heung Bae [Power Engineering Research Institute, KEPCO Engineering and Construction Company, Seongnam (Korea, Republic of)

    2015-02-15

    Since the operation period of nuclear power plants has increased, the degradation of buried pipes gradually increases and recently it seems to be one of the emerging issues. Maintenance on buried pipes needs high quality of management system because outer surface of buried pipe contacts the various soils but inner surface reacts with various electrolytes of fluid. In the USA, USNRC and EPRI have tried to manage the degradation of buried pipes. However, there is little knowledge about the inspection procedure, test and manage program in the domestic nuclear power plants. This paper focuses on the development and build-up of real-time monitoring and control system of buried pipes. Pipes to be tested are tape-coated carbon steel pipe for primary component cooling water system, asphalt-coated cast iron pipe for fire protection system, and pre-stressed concrete cylinder pipe for sea water cooling system. A control system for cathodic protection was installed on each test pipe which has been monitored and controlled. For the calculation of protection range and optimization, computer simulation was performed using COMSOL Multiphysics (Altsoft co.)

  12. Advanced Zinc Phosphate Conversion and Pre-Ceramic Polymetallosiloxane Coatings for Corrosion Protection of Steel and Aluminum, and Characteristics of Polyphenyletheretherketone-Based Materials

    Science.gov (United States)

    1992-09-24

    Finally, the most effective organosilane for use in the fabrica - tion of PTS coatings leading to good corrosion protection was N-[3-(tri...89. References !. T.St;OAMA. L. E KUKACKAimd N. CARC \\ELLO. Froy. Ory. Coat. 10(1990) 173. 2. H w EICH N ER and W. E. SCHOWALTER. Forest...wt % HC1 and 14-17 wt % water. 14. A method for preparing a solution for the fabrica - tion of polymetallicsiloxane coatings which comprises the

  13. Hot Corrosion Mechanism in Multi-Layer Suspension Plasma Sprayed Gd2Zr2O7 /YSZ Thermal Barrier Coatings in the Presence of V2O5 + Na2SO4

    Science.gov (United States)

    Jonnalagadda, Krishna Praveen; Mahade, Satyapal; Curry, Nicholas; Li, Xin-Hai; Markocsan, Nicolaie; Nylén, Per; Björklund, Stefan; Peng, Ru Lin

    2016-12-01

    This study investigates the corrosion resistance of two-layer Gd2Zr2O7/YSZ, three-layer dense Gd2Zr2O7/ Gd2Zr2O7/YSZ, and a reference single-layer YSZ coating with a similar overall top coat thickness of 300-320 µm. All the coatings were manufactured by suspension plasma spraying resulting in a columnar structure except for the dense layer. Corrosion tests were conducted at 900 °C for 8 h using V2O5 and Na2SO4 as corrosive salts at a concentration of approximately 4 mg/cm2. SEM investigations after the corrosion tests show that Gd2Zr2O7-based coatings exhibited lower reactivity with the corrosive salts and the formation of gadolinium vanadate (GdVO4), accompanied by the phase transformation of zirconia was observed. It is believed that the GdVO4 formation between the columns reduced the strain tolerance of the coating and also due to the fact that Gd2Zr2O7 has a lower fracture toughness value made it more susceptible to corrosion-induced damage. Furthermore, the presence of a relatively dense layer of Gd2Zr2O7 on the top did not improve in reducing the corrosion-induced damage. For the reference YSZ coating, the observed corrosion-induced damage was lower probably due to combination of more limited salt penetration, the SPS microstructure and superior fracture toughness of YSZ.

  14. Hot Corrosion Mechanism in Multi-Layer Suspension Plasma Sprayed Gd2Zr2O7 /YSZ Thermal Barrier Coatings in the Presence of V2O5 + Na2SO4

    Science.gov (United States)

    Jonnalagadda, Krishna Praveen; Mahade, Satyapal; Curry, Nicholas; Li, Xin-Hai; Markocsan, Nicolaie; Nylén, Per; Björklund, Stefan; Peng, Ru Lin

    2017-01-01

    This study investigates the corrosion resistance of two-layer Gd2Zr2O7/YSZ, three-layer dense Gd2Zr2O7/ Gd2Zr2O7/YSZ, and a reference single-layer YSZ coating with a similar overall top coat thickness of 300-320 µm. All the coatings were manufactured by suspension plasma spraying resulting in a columnar structure except for the dense layer. Corrosion tests were conducted at 900 °C for 8 h using V2O5 and Na2SO4 as corrosive salts at a concentration of approximately 4 mg/cm2. SEM investigations after the corrosion tests show that Gd2Zr2O7-based coatings exhibited lower reactivity with the corrosive salts and the formation of gadolinium vanadate (GdVO4), accompanied by the phase transformation of zirconia was observed. It is believed that the GdVO4 formation between the columns reduced the strain tolerance of the coating and also due to the fact that Gd2Zr2O7 has a lower fracture toughness value made it more susceptible to corrosion-induced damage. Furthermore, the presence of a relatively dense layer of Gd2Zr2O7 on the top did not improve in reducing the corrosion-induced damage. For the reference YSZ coating, the observed corrosion-induced damage was lower probably due to combination of more limited salt penetration, the SPS microstructure and superior fracture toughness of YSZ.

  15. Corrosion and wear properties of electroless Ni-P plating layer on AZ91D magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    LI Zhong-hou; CHEN Zhi-yong; LIU Sha-sha; ZHENG Feng; DAI A-gan

    2008-01-01

    A direct electroless Ni-P plating treatment was applied to AZ91D magnesium alloy for improving its corrosion resistance and wear resistance. Corrosion resistance of the Ni-P coatings was evaluated by potentiodynamic polarization and immersing experiments in 3.5% NaCl solution. The wear resistance of the coatings was investigated by the wear track and the mass change after ball-on-disk experiment. The results show that corrosion resistance and wear resistance of the AZ91D alloy are greatly improved after direct electroless Ni-P plating. No discoloration is noticed until 4 d of immersion in 3.5% NaCl solution. Potentiodynamic polarization experiments show that the free corrosion potential of magnesium alloy is shifted from -1 500 mV to -250 mV and passivation occurs at 1 350 mV after direct electroless plating. The friction coefficients and wear rates of Ni-P coating and Ni-P coating after tempering are 0.10-0.351, 9.038×10-3 mm3/m and 0.13-0.177, 3.056×10-4 mm3/m, respectively, at a load of 1.5 N with dry sliding. Although minor hurt on corrosion resistance was caused, significant improvement of wear resistance was obtained after tempering treatment of the coating.

  16. Corrosion inhibitors; Los inhibidores de corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Godinez, L. A.; Meas, Y.; Ortega-Borges, R.; Corona, A.

    2003-07-01

    In this paper, we briefly describe the characteristics, cost and electrochemical nature of the corrosion phenomena as well as some of the technologies that are currently employed to minimize its effect. The main subject of the paper however, deals with the description, classification and mechanism of protection of the so-called corrosion inhibitors. Examples of the use of these substances in different aggressive environments are also presented as means to show that these compounds, or their combination, can in fact be used as excellent and relatively cheap technologies to control the corrosion of some metals. In the last part of the paper, the most commonly used techniques to evaluate the efficiency and performance of corrosion inhibitors are presented as well as some criteria to make a careful and proper selection of a corrosion inhibitor technology in a given situation. (Author) 151 refs.

  17. 外锈层对低碳钢腐蚀影响的电化学分析%Electrochemical Analysis Outer Rust Layer Effect on Corrosion Behavior of Low Carbon Steel

    Institute of Scientific and Technical Information of China (English)

    田志强; 孔小东; 王崇碧; 王源升

    2012-01-01

    In the long-term corrosion process, the rust layer formed on the low carbon hull steel may affect its corrosion behavior. The influence mechanism of the outer rust layer on the hull steel corrosion behavior is unclear. A certain type of low carbon steel was selected to soaked in 3mass% NaCl solutions for one year, then of which the electrochemical corrosion characteristic was studied by electrochemical methods before and after removal of the formed outer rust layer. The corrosion resistance before and after the removal of the outer rust layer was compared, and the effect of the outer rust layer on the corrosion of the rust steel was analyzed by use of linear polarization, AC impedance spectroscopy (EIS) and electrochemical noise (EN). The morphology, phase constituents and elemental distribution of the corrosion products formed on the rust and base steels were characterized by EPMA and XRD respectively, then the relevant corrosion mechanism was discassed. The results show that, the corrosion resistance of the steel decreased and the corrosion rate increased after removal of outer rust layer; the removal of the outer rust layer may facilitate the oxygen inward-transportation thereby affecting the electrode process on interface of the rust layer/ metal matrix.%选用某型船用低碳钢,在3mass%NaCl溶液中浸泡一年,用电化学技术研究外锈层去除前后低碳钢的腐蚀电化学特征.运用线性极化、电化学阻抗(EIS)和电化学噪声(EN)技术比较外锈层去除前后钢的耐蚀性,分析外锈层对腐蚀的影响;通过对内、外锈层和裸钢腐蚀形貌的显微观察、对内锈层的电子探针(EMPA)和x射线衍射(XRD)分析,研究外锈层对腐蚀影响的机理.结果表明,去除外锈层使钢的耐蚀性减小,腐蚀速率增大;外锈层的去除导致氧更易于向内输送,进而影响内锈层/金属基体界面的电极过程.

  18. 自组装制备铁质文物保护用纳米缓蚀颗粒%Corrosion inhibitor nano-particles for iron relics protection prepared by self-assembling

    Institute of Scientific and Technical Information of China (English)

    何本桥; 李亭亭; 张桐阳; 沈大娲

    2012-01-01

    The corrosion protection plays a very important role in the protection of iron relics. A novel corrosion inhibitor nano-particle for iron relics was fabricated by consecutively layer-by-layer self-assembling of positive polyethylene imide (PEI), negative poly(sulfonated styrene) (PSS) and positive benzotriazole (BTA) on the surface of negatively charged SiO2 nanoparticles. Transmission electron microscopy, zetasizer and X-ray photoe-lectron spectroscopy (XPS) were employed to characterize the inhibitor nano-particles. Results reveal that the size of particles increases with the increase in the number of coating layers. The surface charge appears corresponding changes. The XPS result shows that the chemical surrounding of nitrogen atoms in the inhibitor nano-particles is changed with the assembly process due to the electrostatic effect between layers. The content of BTA in the inhibitor nano-particle with mono-layer of BTA reached 35. 4mg/g SiO2, which can be readily controlled by improving the number of the PSS and BTA layers.%长效缓蚀材料对于铁质文物的长期保护有着至关重要的作用.通过层层自组装的方法,在带负电荷的SiO2胶粒表面交替组装上了带正电荷的聚乙烯亚胺(PEI)层,带负电荷的聚苯乙烯磺酸钠(PSS)层,以及带正电荷的缓蚀活性成分苯并三氮唑(BTA)层.利用透射电子显微镜、zeta电位仪、X射线光电子能谱仪(XPS)等对纳米缓蚀颗粒进行了表征.结果表明,随着组装过程的进行,胶体粒子尺寸依次增大,颗粒表面zeta电位出现负正交替变化,表面元素化学环境也随之改变,氮原子的结合能随静电作用的增强向高位移动.缓蚀剂的负载量可通过多层组装方式提高,BTA单层负载量可达到35.4mg/g SiO2.

  19. High Temperature Corrosion under Laboratory Conditions Simulating Biomass-Firing: A Comprehensive Characterization of Corrosion Products

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Montgomery, Melanie; Jappe Frandsen, Flemming

    2014-01-01

    characterization of the corrosion products. The corrosion products consisted of three layers: i) the outermost layer consisting of a mixed layer of K2SO4 and FexOy on a partly molten layer of the initial deposit, ii) the middle layer consists of spinel (FeCr2O4) and Fe2O3, and iii) the innermost layer is a sponge......-like Ni3S2 containing layer. At the corrosion front, Cl-rich protrusions were observed. Results indicate that selective corrosion of Fe and Cr by Cl, active oxidation and sulphidation attack of Ni are possible corrosion mechanisms....

  20. High Temperature Corrosion under Laboratory Conditions Simulating Biomass-Firing: A Comprehensive Characterization of Corrosion Products

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Montgomery, Melanie; Jappe Frandsen, Flemming

    2014-01-01

    characterization of the corrosion products. The corrosion products consisted of three layers: i) the outermost layer consisting of a mixed layer of K2SO4 and FexOy on a partly molten layer of the initial deposit, ii) the middle layer consists of spinel (FeCr2O4) and Fe2O3, and iii) the innermost layer is a sponge......-like Ni3S2 containing layer. At the corrosion front, Cl-rich protrusions were observed. Results indicate that selective corrosion of Fe and Cr by Cl, active oxidation and sulphidation attack of Ni are possible corrosion mechanisms....

  1. Adhesion of Model Molecules to Metallic Surfaces, the Implications for Corrosion Protection

    Energy Technology Data Exchange (ETDEWEB)

    De Wit, J. H. W.; Van den Brand, J.; De Wit, F. M.; Mol, J. M. C. [Delf University of Technology and Netherlaands Institute for Metals Research, Delf (Netherlands)

    2008-02-15

    The majority of the described experimental results deal with relatively pure aluminium. Variations were made in the pretreatment of the aluminum substrates and an investigation was performed on the resulting changes in oxide layer composition and chemistry. Subsequently, the bonding behavior of the surfaces was investigated by using model adhesion molecules. These molecules were chosen to represent the bonding functionality of an organic polymer. They were applied onto the pretreated surfaces as a monolayer and the bonding behavior was studied using infrared reflection absorption spectroscopy. A direct and clear relation was found between the hydroxyl fraction on the oxide surfaces and the amount of molecules that subsequently bonded to the surface. Moreover, it was found that most bonds between the oxide surface and organic functional groups are not stable in the presence of water. The best performance was obtained using molecules, which are capable of chemisorption with the oxide surface. Finally, it was found that freshly prepared relatively pure aluminum substrates, which are left in air, rapidly lose their bonding capacity towards organic functional groups. This can be attributed to the adsorption of contamination and water to the oxide surface. in addition the adhesion of a typical epoxy-coated aluminum system was investigated during exposure to water at different temperatures. The coating was found to quite rapidly lose its adhesion upon exposure to water. This rapid loss of adhesion corresponds well with the data where it was demonstrated that the studied epoxy coating only bonds through physisorptive hydrogen bonding, these bonds not being stable in the presence of water. After the initial loss the adhesion of the coating was however found to recover again and even exceeded the adhesion prior to exposure. The improvement could be ascribed to the growth of a thin oxyhydroxide layer on the aluminum substrate, which forms a new, water-stable and stronger bond

  2. Study on the countermeasures against methane outburst of mining multiple upper protective layers in coal seams cluster

    Institute of Scientific and Technical Information of China (English)

    XIE Guang-xiang; LUO Yong

    2005-01-01

    In order to prevent coal and methane outbursts, mining protective layers is an effective means, yet no precedents of mining multiple protective layers is discoveried in seams which includes several seams are prone to outburst like Xinzhuangzi Mine. This paper perfected the related theories through analyzing mining multiple upper protective layers. By means of examining several parameters, it synthetically analyzed and ascertains the protected effectiveness and scope and reasonable parameters, finally obtained the specific indexes and effectiveness of mining multiple protective layers in coal seams cluster.

  3. Corrosion during gasification of biomass and waste

    OpenAIRE

    Källström, Rikard

    1993-01-01

    The gasification of biomass and waste results in severe atmospheric corrosion conditions. The problems arise because of the low oxygen content which prevents the metal forming stable and protective oxide surface layer. Consequently it is possible for the aggressive sulphur and chlorine present in the gas to attack the metal. In the Studsvik CFB gasification pilot plant, which uses RDF (Refuse Derived Fuel), the performance of 20 metallic and ceramic materials has been studied. Materials teste...

  4. Optimization of In-Situ Shot-Peening-Assisted Cold Spraying Parameters for Full Corrosion Protection of Mg Alloy by Fully Dense Al-Based Alloy Coating

    Science.gov (United States)

    Wei, Ying-Kang; Luo, Xiao-Tao; Li, Cheng-Xin; Li, Chang-Jiu

    2017-01-01

    Magnesium-based alloys have excellent physical and mechanical properties for a lot of applications. However, due to high chemical reactivity, magnesium and its alloys are highly susceptible to corrosion. In this study, Al6061 coating was deposited on AZ31B magnesium by cold spray with a commercial Al6061 powder blended with large-sized stainless steel particles (in-situ shot-peening particles) using nitrogen gas. Microstructure and corrosion behavior of the sprayed coating was investigated as a function of shot-peening particle content in the feedstock. It is found that by introducing the in-situ tamping effect using shot-peening (SP) particles, the plastic deformation of deposited particles is significantly enhanced, thereby resulting in a fully dense Al6061 coating. SEM observations reveal that no SP particle is deposited into Al6061 coating at the optimization spraying parameters. Porosity of the coating significantly decreases from 10.7 to 0.4% as the SP particle content increases from 20 to 60 vol.%. The electrochemical corrosion experiments reveal that this novel in-situ SP-assisted cold spraying is effective to deposit fully dense Al6061 coating through which aqueous solution is not permeable and thus can provide exceptional protection of the magnesium-based materials from corrosion.

  5. MATHEMATICAL MODEL FOR CALCULATION OF MINIMUM PRESSURE PERTAINING TO DESTRUCTION OF SURFACE CORROSION LAYER DUE TO IMPACT OF WORKING LIQUID REVERSIVE STREAM

    Directory of Open Access Journals (Sweden)

    I. V. Kachanov

    2014-01-01

    Full Text Available Due to balance of external and internal force capacities a variation quasistatic problem has been solved in the paper. The problem allows to determine optimum values of α and β angles in the accepted field of sliding lines when destruction pressure takes on a minimum value pmin. It has been ascertained that the minimum pressure pmin which is necessary for destruction of a corrosion layer is registered at stream compression coefficient λ = 0,063 and the pressure is equal to 8-17 MPa for the investigated speed range v = 80-140 m/s.

  6. Refractory Materials for Flame Deflector Protection System Corrosion Control: Coatings Systems Literature Survey

    Science.gov (United States)

    Calle, Luz M.; Hintze, Paul E.; Parlier, Christopher R.; Sampson, Jeffrey W.; Coffman, Brekke E.; Coffman, Brekke E.; Curran, Jerome P.; Kolody, Mark R.; Whitten, Mary; Perisich, Steven; Trejo, David

    2009-01-01

    When space vehicles are launched, extreme heat, exhaust, and chemicals are produced and these form a very aggressive exposure environment at the launch complex. The facilities in the launch complex are exposed to this aggressive environment. The vehicle exhaust directly impacts the flame deflectors, making these systems very susceptible to high wear and potential failure. A project was formulated to develop or identify new materials or systems such that the wear and/or damage to the flame deflector system, as a result of the severe environmental exposure conditions during launches, can be mitigated. This report provides a survey of potential protective coatings for the refractory concrete lining on the steel base structure on the flame deflectors at Kennedy Space Center (KSC).

  7. The corrosion protection mechanism of rust converters: An electrochemical impedance spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Collazo, A. [ENCOMAT Group, ETSEI, Universidade de Vigo, Campus Universitario, 36310 Vigo (Spain); Novoa, X.R., E-mail: rnovoa@uvigo.e [ENCOMAT Group, ETSEI, Universidade de Vigo, Campus Universitario, 36310 Vigo (Spain); Perez, C.; Puga, B. [ENCOMAT Group, ETSEI, Universidade de Vigo, Campus Universitario, 36310 Vigo (Spain)

    2010-08-30

    Oxide converters represent an interesting alternative for the protection of steel surfaces that have some degree of rust. Although the mechanism of these converters is not clear, it is assumed that they react with iron oxides and generate new compounds that may have a passivation effect on the steel surface. This last point is not well established, and several authors have even spoken of an accelerating effect of these compounds. We present here a study of the electrochemical behaviour of iron oxides immersed in the rust converter. The modulus of the impedance increases significantly after a certain time of immersion, suggesting that the electronic conductivity and, consequently, the rate of the cathodic reaction tend to decrease.

  8. Corrosion-resistant metallic coatings

    OpenAIRE

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

    2008-01-01

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

  9. UV protective zinc oxide coating for biaxially oriented polypropylene packaging film by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lahtinen, Kimmo, E-mail: kimmo.lahtinen@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Kääriäinen, Tommi, E-mail: tommi.kaariainen@colorado.edu [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Johansson, Petri, E-mail: petri.johansson@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Kotkamo, Sami, E-mail: sami.kotkamo@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Maydannik, Philipp, E-mail: philipp.maydannik@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Seppänen, Tarja, E-mail: tarja.seppanen@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Kuusipalo, Jurkka, E-mail: jurkka.kuusipalo@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Cameron, David C., E-mail: david.cameron@miktech.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland)

    2014-11-03

    Biaxially oriented polypropylene (BOPP) packaging film was coated with zinc oxide (ZnO) coatings by atomic layer deposition (ALD) in order to protect the film from UV degradation. The coatings were made at a process temperature of 100 °C using diethylzinc and water as zinc and oxygen precursors, respectively. The UV protective properties of the coatings were tested by using UV–VIS and infrared spectrometry, differential scanning calorimetry (DSC) and a mechanical strength tester, which characterised the tensile and elastic properties of the film. The results obtained with 36 and 67 nm ZnO coatings showed that the ZnO UV protective layer is able to provide a significant decrease in photodegradation of the BOPP film under UV exposure. While the uncoated BOPP film suffered a complete degradation after a 4-week UV exposure, the 67 nm ZnO coated BOPP film was able to preserve half of its original tensile strength and 1/3 of its elongation at break after a 6-week exposure period. The infrared analysis and DSC measurements further proved the UV protection of the ZnO coatings. The results show that a nanometre scale ZnO coating deposited by ALD is a promising option when a transparent UV protection layer is sought for polymer substrates. - Highlights: • Atomic layer deposited zinc oxide coatings were used as UV protection layers. • Biaxially oriented polypropylene (BOPP) film was well protected against UV light. • Formation of UV degradation products in BOPP was significantly reduced. • Mechanical properties of the UV exposed BOPP film were significantly improved.

  10. Formation mechanism of the graphite-rich protective layer in blast furnace hearths

    Science.gov (United States)

    Jiao, Ke-xin; Zhang, Jian-liang; Liu, Zheng-jian; Liu, Feng; Liang, Li-sheng

    2016-01-01

    A long campaign life of blast furnaces is heavily linked to the existence of a protective layer in their hearths. In this work, we conducted dissection studies and investigated damage in blast furnace hearths to estimate the formation mechanism of the protective layer. The results illustrate that a significant amount of graphite phase was trapped within the hearth protective layer. Furthermore, on the basis of the thermodynamic and kinetic calculations of the graphite precipitation process, a precipitation potential index related to the formation of the graphite-rich protective layer was proposed to characterize the formation ability of this layer. We determined that, under normal operating conditions, the precipitation of graphite phase from hot metal was thermodynamically possible. Among elements that exist in hot metal, C, Si, and P favor graphite precipitation, whereas Mn and Cr inhibit this process. Moreover, at the same hot-face temperature, an increase of carbon concentration in hot metal can shorten the precipitation time. Finally, the results suggest that measures such as reducing the hot-face temperature and increasing the degree of carbon saturation in hot metal are critically important to improve the precipitation potential index.

  11. Formation mechanism of the graphite-rich protective layer in blast furnace hearths

    Institute of Scientific and Technical Information of China (English)

    Ke-xin Jiao; Jian-liang Zhang; Zheng-jian Liu; Feng Liu; Li-sheng Liang

    2016-01-01

    A long campaign life of blast furnaces is heavily linked to the existence of a protective layer in their hearths. In this work, we conducted dissection studies and investigated damage in blast furnace hearths to estimate the formation mechanism of the protective layer. The results illustrate that a significant amount of graphite phase was trapped within the hearth protective layer. Furthermore, on the basis of the thermodynamic and kinetic calculations of the graphite precipitation process, a precipitation potential index related to the formation of the graphite-rich protective layer was proposed to characterize the formation ability of this layer. We determined that, under normal operating conditions, the precipitation of graphite phase from hot metal was thermodynamically possible. Among elements that exist in hot metal, C, Si, and P favor graphite precipitation, whereas Mn and Cr inhibit this process. Moreover, at the same hot-face temperature, an increase of carbon concentration in hot metal can shorten the precipitation time. Finally, the results suggest that measures such as reducing the hot-face tem-perature and increasing the degree of carbon saturation in hot metal are critically important to improve the precipitation potential index.

  12. A Survey of Corrosion and Conditions of Corrosion Protection Systems in Civil Works Structures of the U.S. Army Corps of Engineers

    Science.gov (United States)

    2014-09-01

    report only a small snapshot of all potential problems affecting the Corps’ HSS, but the report does offer relevant insight into the items that have...Individual grains within the met- al become either anodes or cathodes, and adjacent grains become tiny corrosion cells. The cells form small pockets (or pits... annulus between the 1.125- in. anchor rod and the 1.250-in. pipe. The typical rod anchor is 60 ft long and anchored to the backing plate with a nut. The

  13. Analysis of thermal protection characteristics of a rectangular cell filled with PCM/air layer

    Energy Technology Data Exchange (ETDEWEB)

    Ho, C.J.; Chu, C.H. [National Cheng Kung Univ., Tainan (Taiwan, Province of China). Dept. of Mechanical Engineering

    1995-12-31

    The present paper presents a numerical analysis concerning thermal protection characteristics of a rectangular composite cell filled with a solid-liquid phase change material (PCM) and air layer. Inside the composite cell the PCM layer is separated from air layer by a solid partition of negligible thickness. The buoyancy-induced flows developed in both the air-filled layer and the molten PCM zone inside the PCM layer were modeled as two-dimensional laminar Newtonian fluid flow adhering to the Boussinesq approximation. Meanwhile, two-dimensional conduction heat transfer was accounted for the unmelted solid PCM region. Delineation is made via a parametric simulation of the effects of the pertinent parameters: Ste (Stefan number), Sc (subcooling factor), Ra (Rayleigh number), aspect ratio of composite cell, A, and relative thickness ratio A{sub p}/A{sub a}, on the transient thermal protection performance of the composite cell. Results demonstrate that by means of the latent-heat absorption inside the PCM layer, heat penetration across the composite cell can be greatly retarded over an effective duration until a critical instant until the melting front of PCM reaches the partition wall. Such an effective thermal protection duration is found to be a strong function of Ra, Ste, A{sub p}/A{sub a}, and A.

  14. Environmental Friendly Coatings and Corrosion Prevention For Flight Hardware Project

    Science.gov (United States)

    Calle, Luz

    2014-01-01

    Identify, test and develop qualification criteria for environmentally friendly corrosion protective coatings and corrosion preventative compounds (CPC's) for flight hardware an ground support equipment.

  15. Stress corrosion cracking of brass in ammonia solution

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Brass foil with a protective layer formed on one side was deflected during corrosion in an ammonia solution under various applied potentials, and then corrosion-induced stress generated at brass/dezincification layer under different potentials could be measured. At the same time, susceptibility to stress corrosion cracking(SCC) of brass in the ammonia solution under various applied potentials was measured using a single-edge notched specimen. At open-circuit potential, both corrosion-induced tensile stress and susceptibility to SCC(Iσ) had a maximum value. Both tensile stress σp and susceptibility Iσ decreased slightly under anodic polarization, but reduced steeply with the decrease in potential of cathodic polarization. At the cathodic potential of -500  mV(vs SCE), corrosion-induced stress became compressive because of copper-plating layer, correspondingly, susceptibility to SCC was zero. Therefore, the variation of SCC susceptibility with potential is consistent with that of the corrosion-induced additive stress.

  16. Corrosion protection of solar-collctor heat exchangers with electrochemically deposited films. Final report, 15 May 1978-15 November 1979. [Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Koch, V.R.; Schnaper, G.H.; Brummer, S.B.

    1980-05-01

    The goal of this program was the demonstration of a novel corrosion protection technique for the common solar collector metals: Al, Cu, and Fe as mild steel. This involves the electrochemical deposition of thin, adherent polymer films on the interior of heat-exchanger tubes by application of a current in the presence of a suitable organic monomer. Polyphenylene oxide (PPO) films were anodically deposited onto Cu and Fe coupons from methanolic media. However, defects in these films afforded poor corrosion protection. In an attempt to circumvent this problem, suitably functionalized PPO films were cross-linked via Schiff base formation in a subsequent chemical step. While these chemically modified PPO films were demonstrably more resistant to ethylene glycol H/sub 2/O media at elevated temperatures, they were eventually undetermined by the thermal transfer fluid. Cinnamaldehyde, a styrene-type monomre, has been successfully electrodeposited onto Al coupons. This process involved a constant, albeit unreferenced potential technique in which the Al is made the negative electrode. Cathodic deposition onto Al avoids passivating Al/sub 2/O/sub 3/ barrier coating formation, and is amenable to the cross-linking technique. Filmed and cross-linked Al samples stored at elevated temperatures resisted corrosive processes compared to unfilmed control samples. Pitting, however, was the ultimate fate of all filmed samples.

  17. 海底管道腐蚀与防护措施研究现状%Research Situation of Corrosion Protection for Submarine Pipeline

    Institute of Scientific and Technical Information of China (English)

    张炬; 陈振栋

    2015-01-01

    Submarine pipeline is the main carrier of offshore oil and gas gathering and transportation, the lifeline of offshore oil and gas development. Corrosion is a key factor affecting the reliability and service life of submarine pipeline.it is necessary to makeeffective anticorrosive measures to protect it. This paper describes the reasons of corrosion and discusses the research situation of corrosion protection for Submarine pipeline.%海底管道是海上油气集输的主要载体,是海上油气田开发的生命线.腐蚀是影响海底管道可靠性及其使用寿命的关键因素,对海底管道采取有效防腐蚀措施是保障其正常运行的必要措施.本文主要分析了海底管道的腐蚀原因,论述了海底管道腐蚀防护的研究现状.

  18. An evaluation of corrosion protection by two epoxy primers on 2219-T87 and 7075-T73 aluminum

    Science.gov (United States)

    Mendrek, M. J.

    1992-01-01

    A comparison of the corrosion protection provided by two amine epoxy primers was made using salt fog, alternate immersion, and total immersion as exposure media. The study is the result of a request to use an unqualified low volatile organic carbon (VOC) primer (AKZO 463-6-78) in place of the current primer (AKZO 463-6-3) because environmental regulations have eliminated use of the current primer in many states. Primed, scribed samples of 2219-T87 and 7075-T73 aluminum were exposed to 5-percent NaCl salt fog and 3.5-percent NaCl alternate immersion for a period of 90 days. In addition, electrode samples immersed in 3.5-percent NaCl were tested using electrochemical impedance spectroscopy (EIS). The EG&G model 368 ac impedance measurement system was used to monitor changing properties of AKZO 463-6-78 and AKZO 463-6-3 primed 2219-T87 aluminum for a period of 30 days. The response of the corroding system of a frequency scan can be modeled in terms of an equivalent circuit consisting of resistors and capacitors in a specific arrangement. Each resistor/capacitor combination represents physical processes taking place within the electrolyte, at the electrolyte/primer surface, within the coating, and at the coating/substrate surface. Values for the resistors and capacitors are assigned following a nonlinear least squares fit of the data to the equivalent circuit. Changes in the values of equivalent circuit parameters during the 30-day exposure allow assessment of the time to and mechanism of coating breakdown.

  19. Corrosion protection ability of self-assembled monolayer of 3-amino-5-mercapto-1,2,4-triazole on copper electrode

    Energy Technology Data Exchange (ETDEWEB)

    Rajkumar, Ganesan; Sethuraman, Mathur Gopalakrishnan, E-mail: mgsethu@rediffmail.com

    2014-07-01

    The self-assembled monolayer (SAM) of 3-amino-5-mercapto-1,2,4-triazole (AMTa) was formed on a copper surface and characterized using cyclic voltammetry, Fourier Transform Infra-red spectroscopy and scanning electron microscopy. Quantum chemical calculations suggested the stronger interaction between AMTa and copper. The protection ability of SAM has been evaluated using electrochemical impedance spectroscopy and potentiodynamic polarization measurements. The formed monolayer showed significant protection ability in 1% NaCl medium. The enhanced corrosion protection ability could be due to the compact film structure which blocks the electron transfer from the solution to AMTa monolayer modified copper substrate. - Highlights: • Self-assembled monolayer (SAM) of AMTa has been achieved on copper surface. • Monolayer formed has been duly characterized. • SAM of AMTa has been shown to offer significant protection to copper in NaCl medium.

  20. 硫磺回收装置的腐蚀与防护%Corrosion and protection of SRU unit

    Institute of Scientific and Technical Information of China (English)

    王凯; 刘文彬; 杨剑锋; 陈良超

    2015-01-01

    The feed material for SRU unit is acid gas, therefore corrosive mediums almost run through the en-tire unit. Corrosion prevention is always the key to ensuring safety in production for a long time. Use EDS method-ology to analyse the quench tower, exchangers and tail gas incinerator in this unit. Firstly, check the external cor-rosion, and then use EDS to analyse the corrosion cause and corrosion type. According to the conclusion of analy-sis, some suggestions on corrosion prevention are raised.%硫磺回收装置的原料主要是酸性气体,因此腐蚀性介质几乎贯穿全装置,腐蚀的防治始终是装置可以长时间安全运行的关键。运用能谱分析法(EDS,Energy Dispersive Spectrometer)对急冷塔、换热器和尾气焚烧炉进行分析,首先对设备进行外部宏观检查,然后使用能谱分析法分析腐蚀原因和腐蚀类型,并根据分析结果,讨论了相应的腐蚀防护策略。

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

    Indian Academy of Sciences (India)

    T Dhanabal; G Amirthaganesan; J Ravichandran

    2011-06-01

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

  2. The effect of cerium-based conversion treatment on the cathodic delamination and corrosion protection performance of carbon steel-fusion-bonded epoxy coating systems

    Science.gov (United States)

    Ramezanzadeh, B.; Rostami, M.

    2017-01-01

    The effect of surface pre-treatment of pipe surface by green cerium compound and phosphoric acid solution on the fusion-bonded epoxy (FBE) coating performance was studied. The composition and surface morphology of the steel samples treated by acid and Ce solutions were characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), equipped with energy dispersive spectroscopy (EDS). Also, the surface free energy was evaluated on these samples through contact angle measurements. In addition, the effect of Ce and acid washing procedures on the adhesion properties and corrosion protection performance of the FBE was examined by pull-off, salt spray and electrochemical impedance spectroscopy (EIS) tests. Results showed that compared to acid washing, the chemical treatment by Ce solution noticeably increased the surface free energy of steel, improved the adhesion properties of FBE, decreased the cathodic delamination rate of FBE, and enhanced the coating corrosion resistance compared to the acid washed samples.

  3. Influence of rare earth elements on corrosion behavior of Al-brass in marine water

    Institute of Scientific and Technical Information of China (English)

    LIN Gaoyong; ZHOU Yuxiong; ZENG Juhua; ZOU Yanming; LIU Jian; SUN Liping

    2011-01-01

    The corrosion behaviors of Al-brass in stagnant and flowing marine water as a function of combinative rare earths (Ce and La) addition were investigated by electrochemical techniques,X-ray diffraction (XRD) and scanning electron microscopy (SEM).It was demonstrated that RE elements could make the corrosion product layer more protective and strengthen the cohesion between the film and matrix in stagnant seawater.The electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) analysis confirmed that a duplex layer,which was mainly composed of an inner A12O3 with trace amounts of RE compounds and an outer basic chloride of copper or zinc like (Cu,Zn)2Cl(OH)3,Cu(OH)Cl and CuCl2·3Cu(OH)2 layer was formed on RE-contained Al-brass surface and that the inner layer was responsible for the good corrosion resistance of the alloy.While only a porous and non-protective corrosion product layer was formed on the Al-brass alloy without RE addition,which made small values of the corrosion resistance.Additionally,in flowing marine water with velocity about 2 m/s,pitting corrosion occurred on the M-brass surface and RE addition could availably decrease pitting sensitivity of the alloy.

  4. HVOF Thermal Spray TiC/TiB2 Coatings for AUSC Boiler/Turbine Components for Enhanced Corrosion Protection

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, Kanchan [Southern Illinois Univ., Carbondale, IL (United States). Dept. of Mechanical Engineering and Energy Processes; Koc, Rasit [Southern Illinois Univ., Carbondale, IL (United States). Dept. of Mechanical Engineering and Energy Processes; Fan, Chinbay [Gas Technology Inst., Des Plaines, IL (United States)

    2016-12-07

    The high temperatures of operations still pose significant risk of degradation and fatigue from oxidizing, corroding and eroding environment. In addition to unused O2, water from combustion and SOx from the coal sulfur oxidation that result in highly corrosive environment, acid gases such as HCl and other sulfur compounds may also be present. These adverse effects are further accelerated due to the elevated temperatures. In addition, ash particulates and unburnt carbon and pyritic sulfur can cause erosion of the surface and thus loss of material. Unburnt carbon and pyritic sulfur may also cause localized reduction sites. Thus, fireside corrosion protection and steam oxidation protection alternatives to currently used Ni-Cr overlays need to be identified and evaluated. Titanium carbide (TiC) is a suitable alternative on account of the material features such as the high hardness, the high melting point, the high strength and the low density for the substitution or to be used in conjunction with NiCr for enhancing the fireside corrosion and erosion of the materials. Another alternative is the use of titanium boride as a coating for chemical stability required for long-term service and high erosion resistance over the state-of-the-art, high fracture toughness (K1C ~12 MPam1/2) and excellent corrosion resistance (kp~1.9X10-11 g2/cm4/s at 800°C in air). The overarching aim of the research endeavor was to synthesize oxidation, corrosion and wear resistant TiC and TiB2 coating powders, apply thermal spray coating on existing boiler materials and characterize the coated substrates for corrosion resistance for applications at high temperatures (500 -750 °C) and high pressures (~350 bars) using the HVOF process and to demonstrate the feasibility of these coating to be used in AUSC boilers and turbines.

  5. Effect of gold nanorods in an MgO protective layer of AC plasma display panels.

    Science.gov (United States)

    Cho, Seok Ho; Lee, Seong Min; Kim, Woo Hyun; Choi, Kyung Cheol

    2015-04-15

    We propose a modified MgO protective layer for alternating current plasma display panels. The modified MgO protective layer of the panel tested here has a structure that incorporates silica-coated Au nanorods (NRs), leading to localized surface plasmon resonance (LSPR) in the near-infrared (IR) region. The silica-coated Au NRs were synthesized by a simple chemical method and inserted into an MgO protective layer using an air-spray method. The operating voltage of the proposed structure was decreased by 10 V. The luminance and luminous efficacy of the test panel part with the silica-coated Au NRs both increased by about 15%. According to the measured results of the IR response time, the sustain discharge time lag was reduced. In addition, by inserting the silica-coated Au NRs into the MgO protective layer, a decrease of the IR emission proceeding from the plasma discharge was acquired. Finally, we investigated the LSPR effect of the silica-coated Au NRs in a simulation with a finite-difference time domain method.

  6. Corrosion Rate of Hydrogenation to C110 Casing in High H2S Environment

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi; LI Changjin; ZHANG Jiyin; SHI Taihe

    2012-01-01

    The corrosion behavior of C110 bushing at high temperature and high pressure with a high H2S / CO2 was studied,and a basis for the materials selection of sour gas well bushing was provided in H2S,CO2 and saline coexisting environment.Under acidic condiction,hydrogen atoms greatly entered into the material and caused the material properties changed.Weight loss method was used to study the corrosion rate of hydrogen charging samples and original untreated samples in simulated oil field environment.PAR2273 electrochemical workstation was used to examine the electrochemical performance of samples untreated,hydrogen charging after reacting in autoclave.The corrosion product film was observed through SEM.The experimental results show that sample with hydrogen charging has a much more obvious partial corrosion and pitting corrosion than the untreated blank sample even the downhole corrosion speed of bushing is increased after being used for a period of time.Polarization curve shows the corrosion tendency is the same between sample with or without hydrogen charging and corrosion tendency is reduced by corrosion product film.A layer of dense product film formed on the surface of samples provides a certain protective effect to the matrix,but cracked holes which will accelerate partial corrosion of the sample were also observed.

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

    Energy Technology Data Exchange (ETDEWEB)

    Crivelaro, Marcos

    2002-07-01

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

  8. Microencapsulation Technology for Corrosion Mitigation by Smart Coatings

    Science.gov (United States)

    Buhrow, Jerry; Li, Wenyan; Jolley, Scott; Calle, Luz M.

    2011-01-01

    A multifunctional, smart coating for the autonomous control of corrosion is being developed based on micro-encapsulation technology. Corrosion indicators as well as corrosion inhibitors have been incorporated into microcapsules, blended into several paint systems, and tested for corrosion detection and protection effectiveness. This paper summarizes the development, optimization, and testing of microcapsules specifically designed to be incorporated into a smart coating that will deliver corrosion inhibitors to mitigate corrosion autonomously. Key words: smart coating, corrosion inhibition, microencapsulation, microcapsule, pH sensitive microcapsule, corrosion inhibitor, corrosion protection pain

  9. THE CORROSION RESISTANCE OF THE BASE GEOPOLYMER FLY ASH

    Directory of Open Access Journals (Sweden)

    Paweł Mazur

    2013-09-01

    Full Text Available The article presents research on a new engineering material which becomes geopolymer. This is the material used to form a protective layer, to provide a high moisture absorption capacity, however, its composition is highly alkaline and, therefore, its absorption does not affect adversely the protected structures. The research included the effects of various corrosive environments for a change in weight of the test samples during the test, as well as the surface structure on a macroscopic scale.

  10. Corrosion of Metal-Matrix Composites with Aluminium Alloy Substrate

    Directory of Open Access Journals (Sweden)

    B. Bobic

    2010-03-01

    Full Text Available The corrosion behaviour of MMCs with aluminium alloy matrix was presented. The corrosion characteristics of boron-, graphite-, silicon carbide-, alumina- and mica- reinforced aluminium MMCs were reviewed. The reinforcing phase influence on MMCs corrosion rate as well as on various corrosion forms (galvanic, pitting, stress corrosion cracking, corrosion fatique, tribocorrosion was discussed. Some corrosion protection methods of aluminium based MMCs were described

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

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, G. E-mail: georg.mueller@ihm.fzk.de; Heinzel, A.; Konys, J.; Schumacher, G.; Weisenburger, A.; Zimmermann, F.; Engelko, V.; Rusanov, A.; Markov, V

    2002-02-01

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

  12. Countermeasures to corrosion on water walls. Part 2; Aatgaerder mot eldstadskorrosion paa panntuber. Etapp 2

    Energy Technology Data Exchange (ETDEWEB)

    Storesund, Jan; Elger, Ragna; Nordling, Magnus; Viklund, Peter

    2011-01-15

    Background: The problems with water wall corrosion have been accelerating over the last years. There are a number of reasons for this. Originally mild steels were successfully used in power plant water walls. The magnetite layer that forms at the fire side of the tubes when the boiler is taken into operation protected from corrosion attack. The fuels at that time (oil, coal, gas) were not able to break down the magnetite by corrosion. In addition, there were no restrictions for pollutions and for the combustion itself that could contribute to corrosion attack. The usage of fossil fuels has decreased substantially over the last 25 years, not least by environmental reasons. As a replacement a number of different kinds of bio mass fuels are used. These are typically more or less corrosive and the magnetite layers are attacked. The corrosion is often supported by reducing conditions as a result of the restrictions of the NO{sub x}-pollution. Also the waste fuelled boilers have huge corrosion problems. This has been the case for the last 25 years but nowadays the number of such plants is so much higher and the service data have been turned up. Corrosion protection of the water wall tubes started to be successful in the beginning of the seventies by the introduction of the composite tube. Such tubes are fabricated by mild steel or a low alloy core and corrosion resistant austenite steel or nickel base as an about 2 mm thick corrosion protective coating. Weld cladding of the water wall tubes was introduced in the 1980's as a significantly cheaper alternative to the composite tubes. Thermal spraying and refractory protection are other methods. These corrosion protection methods have not always been effective. For example, depending on incorrect materials selection, incorrect performance and incorrect method selection for the current corrosion or erosion attack. Therefore, there is a need for increased knowledge of which protection method and material that will work

  13. Countermeasures to corrosion on water walls. Part 2; Aatgaerder mot eldstadskorrosion paa panntuber. Etapp 2

    Energy Technology Data Exchange (ETDEWEB)

    Storesund, Jan; Elger, Ragna; Nordling, Magnus; Viklund, Peter

    2011-01-15

    Background: The problems with water wall corrosion have been accelerating over the last years. There are a number of reasons for this. Originally mild steels were successfully used in power plant water walls. The magnetite layer that forms at the fire side of the tubes when the boiler is taken into operation protected from corrosion attack. The fuels at that time (oil, coal, gas) were not able to break down the magnetite by corrosion. In addition, there were no restrictions for pollutions and for the combustion itself that could contribute to corrosion attack. The usage of fossil fuels has decreased substantially over the last 25 years, not least by environmental reasons. As a replacement a number of different kinds of bio mass fuels are used. These are typically more or less corrosive and the magnetite layers are attacked. The corrosion is often supported by reducing conditions as a result of the restrictions of the NO{sub x}-pollution. Also the waste fuelled boilers have huge corrosion problems. This has been the case for the last 25 years but nowadays the number of such plants is so much higher and the service data have been turned up. Corrosion protection of the water wall tubes started to be successful in the beginning of the seventies by the introduction of the composite tube. Such tubes are fabricated by mild steel or a low alloy core and corrosion resistant austenite steel or nickel base as an about 2 mm thick corrosion protective coating. Weld cladding of the water wall tubes was introduced in the 1980's as a significantly cheaper alternative to the composite tubes. Thermal spraying and refractory protection are other methods. These corrosion protection methods have not always been effective. For example, depending on incorrect materials selection, incorrect performance and incorrect method selection for the current corrosion or erosion attack. Therefore, there is a need for increased knowledge of which protection method and material that will work

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

    Science.gov (United States)

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

    2016-12-01

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

  15. Surfactant-free carnauba wax dispersion and its use for layer-by-layer assembled protective surface coatings on wood

    Science.gov (United States)

    Lozhechnikova, Alina; Bellanger, Hervé; Michen, Benjamin; Burgert, Ingo; Österberg, Monika

    2017-02-01

    Protection from liquid water and UV radiation are equally important, and a sophisticated approach is needed when developing surface coatings that preserve the natural and well-appreciated aesthetic appearance of wood. In order to prevent degradation and prolong the service life of timber, a protective coating was assembled using carnauba wax particles and zinc oxide nanoparticles via layer-by-layer deposition in water. For this purpose, a facile sonication route was developed to produce aqueous wax dispersion without any surfactants or stabilizers. The suspension was stable above pH 4 due to the electrostatic repulsion between the negatively charged wax particles. The particle size could be controlled by the initial wax concentration with average particle sizes ranging from 260 to 360 nm for 1 and 10 g/L, respectively. The deposition of wax particles onto the surface of spruce wood introduced additional roughness to the wood surface at micron level, while zinc oxide provided nano roughness and UV-absorbing properties. In addition to making wood superhydrophobic, this novel multilayer coating enhanced the natural moisture buffering capability of spruce. Moreover, wood surfaces prepared in this fashion showed a significant reduction in color change after exposure to UV light. A degradation of the wax through photocatalytic activity of the ZnO particles was measured by FTIR, indicating that further studies are required to achieve long-term stability. Nevertheless, the developed coating showed a unique combination of superhydrophobicity and excellent moisture buffering ability and some UV protection, all achieved using an environmentally friendly coating process, which is beneficial to retain the natural appearance of wood and improve indoor air quality and comfort.

  16. Elasto-Plasticity Critical Corrosive Ratio Model for RC Structure Corrosive Expanding Crack

    Institute of Scientific and Technical Information of China (English)

    CHEN Yueshun; LU Yiyan; LIU Li

    2007-01-01

    The parameter of filling expanding ratio n, plasticity factor k1 and deformation parameter k2 is raised, and then the elasto-plasticity critical corrosive ratio model for RC structure corrosive expanding crack based on elasto-plasticity theory is constructed in this paper. The influences of parameters such as filling expansion ratio n, plasticity factor k1, deformation parameter k2, Poisson ratio of concrete v, diameter of reinforced bar d and protective layer thickness c on the critical corrosive ratio are researched by theory analysis and experiments. The experimental results validate the accuracy of the model. According to the experimental study, the least squares solution is calculated as n=1.8,k1 =0.61,k2 =0.5.

  17. Magnetic characterization of the nickel layer protecting the copper wires in harsh applications

    Directory of Open Access Journals (Sweden)

    Roger Daniel

    2017-06-01

    Full Text Available High Temperature (HT° motor coils open new perspectives for extending the applications of electrical motors or generators to very harsh environments or for designing very high power density machines working with high internal temperature gradients. Over a temperature of 300°C, the classic enameled wire cannot work permanently, the turn-to-turn insulation must be inorganic and made with high temperature textiles or vitro-ceramic compounds. For both cases, a diffusion barrier must protect the copper wire against oxidation. The usual solution consists of adding a nickel layer that yields an excellent chemical protection. Unfortunately, the nickel has ferromagnetic properties that change a lot the skin effect in the HT wire at high frequencies. For many applications such as aeronautics, electrical machines are always associated with PWM inverters for their control. The windings must resist to high voltage short spikes caused by the fast fronted pulses imposed by the feeding inverter. The nickel protection layer of the HT° inorganic wire has a large influence on the high frequency behavior of coils and, consequently, on the magnitude of the voltage spikes. A good knowledge of the non-linear magnetic characteristics of this nickel layer is helpful for designing reliable HT inorganic coils. The paper presents a method able to characterize non-linear electromagnetic properties of this nickel layer up to 500°C.

  18. Carbon-layer-protected cuprous oxide nanowire arrays for efficient water reduction

    KAUST Repository

    Zhang, Zhonghai

    2013-02-26

    In this work, we propose a solution-based carbon precursor coating and subsequent carbonization strategy to form a thin protective carbon layer on unstable semiconductor nanostructures as a solution to the commonly occurring photocorrosion problem of many semiconductors. A proof-of-concept is provided by using glucose as the carbon precursor to form a protective carbon coating onto cuprous oxide (Cu2O) nanowire arrays which were synthesized from copper mesh. The carbon-layer-protected Cu2O nanowire arrays exhibited remarkably improved photostability as well as considerably enhanced photocurrent density. The Cu2O nanowire arrays coated with a carbon layer of 20 nm thickness were found to give an optimal water splitting performance, producing a photocurrent density of -3.95 mA cm-2 and an optimal photocathode efficiency of 0.56% under illumination of AM 1.5G (100 mW cm-2). This is the highest value ever reported for a Cu 2O-based electrode coated with a metal/co-catalyst-free protective layer. The photostability, measured as the percentage of the photocurrent density at the end of 20 min measurement period relative to that at the beginning of the measurement, improved from 12.6% on the bare, nonprotected Cu2O nanowire arrays to 80.7% on the continuous carbon coating protected ones, more than a 6-fold increase. We believe that the facile strategy presented in this work is a general approach that can address the stability issue of many nonstable photoelectrodes and thus has the potential to make a meaningful contribution in the general field of energy conversion. © 2013 American Chemical Society.

  19. Corrosion protection by a recirculating tank atmosphere. System BelgEx; Korrosionsskydd med hjaelp av aatercirkulerad tankatmosfaer. System BaelgEx

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Leif [Chalmers Univ. of Tech., Goeteborg (Sweden). Monitoring Center

    2002-02-01

    A system for protection against air leakage and corrosion in non-pressurised hot water accumulators has been tested. The system utilises a rubber bellows to create a volume for gas expansion. The system is a Swedish innovation, patent pending, June 2001. The monitoring and evaluation show that the system has a very good protecting capacity. The concentration of dissolved oxygen was below the detection limit for the measurement during the entire period of monitoring, several months. Thus the oxygen concentration was well below 4 ppb, which should be compared to 20 ppb, the maximum value recommended by the district-heating companies for their process water. As a consequence it may be concluded that the technical life-span of the protected accumulator would be limited by external factors rather than internal corrosion. The bellows system is low-cost and virtually maintenance-free. If correctly dimensioned it may totally prohibit aeration of the accumulator. Draining of condensed water back to the accumulator is a feature of the construction. This has worked well, and the amount of condensed water was very small. This report describes the system and its operational principles. It also comments briefly on the theoretical background. A short section comments on the system dimensioning.

  20. In-situ monitoring of undercoating corrosion damage by Direct Optical Interrogation (DOI)

    Science.gov (United States)

    Lopez-Garrity, Meng

    An approach referred to as "Direct Optical Interrogation" (DOI) has been developed as an extension of the thin film pitting approach developed and used by Frankel and others. Samples were prepared by depositing Al and Al-Cu alloy metallizations about 800 nm thick on glass substrates. These metallizations were then coated with various coatings and coating systems. Samples were introduced to aggressive environments and the progression of corrosion of the metallization under the coating was monitored in situ using low power videography. Because metallizations were thin, corrosion quickly penetrated through the metal layer to the glass substrate and then spread laterally. Measurement of the lateral spread of corrosion enabled non-electrochemical assessment of the corrosion kinetics. In Al-Cu thin films, both aged and as-deposited, corrosion sites are irregularly shaped because there is not enough cathodic current to propagate the entire corrosion site margin at equal rates. In a number of cases, corrosion propagates with a filamentary morphology resembling filiform corrosion. Cu played a strong role in determining under coating corrosion morphology and growth kinetics in experiments with Al-Cu thin films substrates. As-deposited Al-Cu metallizations were more corrosion resistant than aged metallization and both were more corrosion resistant than pure Al. Cu-rich dendrites were formed on the corrosion front. Corrosion rate (current density) was calculated using Faraday's law by collecting corrosion site perimeter and bottom area. Systematic exploration of the effects of a chromate and chromate-free conversion coatings, chromate and chromate-free primer coatings and the presence or absence of a polyurethane topcoat confirmed the extraordinary corrosion protection by chromates. A commercial praseodymium-pigmented primer coating was not particularly effective in retarding undercoating corrosion site growth unless paired with a chromate conversion coating. The presence of a