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Sample records for continuous hot-dip galvanizing

  1. Effect of hot-dip galvanizing processes on the microstructure and mechanical properties of 600-MPa hot-dip galvanized dual-phase steel

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    Kuang, Chun-fu; Zheng, Zhi-wang; Wang, Min-li; Xu, Quan; Zhang, Shen-gen

    2017-12-01

    A C-Mn dual-phase steel was soaked at 800°C for 90 s and then either rapidly cooled to 450°C and held for 30 s (process A) or rapidly cooled to 350°C and then reheated to 450°C (process B) to simulate the hot-dip galvanizing process. The influence of the hot-dip galvanizing process on the microstructure and mechanical properties of 600-MPa hot-dip galvanized dual-phase steel (DP600) was investigated using optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and tensile tests. The results showed that, in the case of process A, the microstructure of DP600 was composed of ferrite, martensite, and a small amount of bainite. The granular bainite was formed in the hot-dip galvanizing stage, and martensite islands were formed in the final cooling stage after hot-dip galvanizing. By contrast, in the case of process B, the microstructure of the DP600 was composed of ferrite, martensite, bainite, and cementite. In addition, compared with the yield strength (YS) of the DP600 annealed by process A, that for the DP600 annealed by process B increased by approximately 50 MPa because of the tempering of the martensite formed during rapid cooling. The work-hardening coefficient ( n value) of the DP600 steel annealed by process B clearly decreased because the increase of the YS affected the computation result for the n value. However, the ultimate tensile strength (UTS) and elongation ( A 80) of the DP600 annealed by process B exhibited less variation compared with those of the DP600 annealed by process A. Therefore, DP600 with excellent comprehensive mechanical properties (YS = 362 MPa, UTS = 638 MPa, A 80 = 24.3%, n = 0.17) was obtained via process A.

  2. Processing hot-dip galvanized AHSS grades: a challenging task

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    Pichler, A.; Hebesberger, T.; Tragl, E.; Traint, S.; Faderl, J.; Angeli, G.; Koesters, K. [voestalpine Stahl GmbH, Linz (Austria)

    2005-07-01

    High-strength thin sheet steel grades have gained a considerable market share. At present a very strong demand has been observed for DP (dual-phase), CP (complex phase) and TRIP grades, which are often summarized as advanced high-strength steel grades (AHSS). The potential benefits of applying AHSS grades were impressively demonstrated in the ULSAC-AVC project, in which a remarkable reduction in mass and an increase in stiffness and crash safety were achieved by using a very high share of AHSS steel grades. The present contribution concentrates on hot-dip galvanized AHSS thin sheet grades. The hot-dip galvanizeability of such grades is critically discussed after an overview is provided of the metallurgy of AHSS grades, including microstructure, mechanical properties, phase transformations and required alloy design. Based on these fundamentals, the processing of AHSS grades in the hot-dip galvanizing line is discussed and the resulting properties presented. (orig.)

  3. Effect of Dynamic Flow on the Structure of Inhibition Layer in Hot-dip Galvanizing

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    Jin, Young Sool; Kim, Myung Soo; Kim, Su Young [POSCO Technical Research Labs., Gwangyang (Korea, Republic of); Paik, Doo Jin [POSCO Kwangyang Steel Works, Gwangyang (Korea, Republic of)

    2011-02-15

    The effect of dynamic flow or forced convection were investigated and compared on the formation of inhibition layer, galvanizing and galvannealing reactions through the hot-dip galvanizing simulator with the oscillation of specimen in zinc bath, continuous galvanizing pilot plant with zinc pumping system through the snout and continuous galvanizing operation with Dynamic Galvanizing{sup TR} system. The interfacial Al pick-up was not consistent between the results of simulator, pilot plant and line operation, but the morphology of inhibition layer became compact and refined by the forced convection. The growth of Fe-Zn intermetallics at the interface was inhibited by the forced convection, whereas the galvannealing rate would be a little promoted.

  4. Effect of Dynamic Flow on the Structure of Inhibition Layer in Hot-dip Galvanizing

    International Nuclear Information System (INIS)

    Jin, Young Sool; Kim, Myung Soo; Kim, Su Young; Paik, Doo Jin

    2011-01-01

    The effect of dynamic flow or forced convection were investigated and compared on the formation of inhibition layer, galvanizing and galvannealing reactions through the hot-dip galvanizing simulator with the oscillation of specimen in zinc bath, continuous galvanizing pilot plant with zinc pumping system through the snout and continuous galvanizing operation with Dynamic Galvanizing TR system. The interfacial Al pick-up was not consistent between the results of simulator, pilot plant and line operation, but the morphology of inhibition layer became compact and refined by the forced convection. The growth of Fe-Zn intermetallics at the interface was inhibited by the forced convection, whereas the galvannealing rate would be a little promoted

  5. Application of thermodynamics and Wagner model on two problems in continuous hot-dip galvanizing

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    Liu, Huachu; He, Yanlin; Li, Lin

    2009-12-01

    Firstly in this paper, the influence of H 2 and water vapor content on selective oxidation occurred in continuous hot-dip galvanizing has been studied by thermodynamics and Wagner model, then, the Gibbs energy of each possible aluminothermic reducing reaction in zinc bath was calculated in order to judge the possibility of these reactions. It was found that oxides' amounts and oxidation type were greatly related to the H 2 and water content in the annealing atmosphere. And from the view of thermodynamics, surface oxides (MnO, Cr 2O 3, SiO 2 etc.) can be reduced by the effective Al in Zn bath.

  6. Application of thermodynamics and Wagner model on two problems in continuous hot-dip galvanizing

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    Liu Huachu; He Yanlin [School of Material Science and Engineering, Shanghai University, No.149 Yanchang Road Shanghai 200072 (China); Li Lin, E-mail: liling@shu.edu.cn [School of Material Science and Engineering, Shanghai University, No.149 Yanchang Road Shanghai 200072 (China)

    2009-12-15

    Firstly in this paper, the influence of H{sub 2} and water vapor content on selective oxidation occurred in continuous hot-dip galvanizing has been studied by thermodynamics and Wagner model, then, the Gibbs energy of each possible aluminothermic reducing reaction in zinc bath was calculated in order to judge the possibility of these reactions. It was found that oxides' amounts and oxidation type were greatly related to the H{sub 2} and water content in the annealing atmosphere. And from the view of thermodynamics, surface oxides (MnO, Cr{sub 2}O{sub 3}, SiO{sub 2} etc.) can be reduced by the effective Al in Zn bath.

  7. Morphology and antimony segregation of spangles on batch hot-dip galvanized coatings

    Science.gov (United States)

    Peng, Shu; Lu, Jintang; Che, Chunshan; Kong, Gang; Xu, Qiaoyu

    2010-06-01

    Spangles produced by batch hot-dip galvanizing process have a rougher surface and a greater surface segregation of alloying element compared with those in continuous hot-dip galvanizing line (CGL), owing to the cooling rate of the former is much smaller than that of the later. Therefore, typical spangles on a batch hot-dipped Zn-0.05Al-0.2Sb alloy coating were investigated. The chemical, morphological characterization and identification of the phases on the spangles were examined by scanning electron microscopy (SEM), backscattered electron imaging (BSE), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS) and X-ray diffraction analysis (XRD). The results showed that the coating surface usually exhibited three kinds of spangles: shiny, feathery and dull spangle, of which extensively antimony surface segregation was detected. The nature of precipitate on the coating surface was identified as β-Sb 3Zn 4, The precipitated β-Sb 3Zn 4 particles distributed randomly on the shiny spangle surface, both β-Sb 3Zn 4 particles and dentritic segregation of antimony dispersed in the dendritic secondary arm spacings of the feathery spangle and on the whole dull spangle surface. The dentritic segregation of antimony and precipitation of Sb 3Zn 4 compound are discussed by a proposed model.

  8. Electrochemical Corrosion Behavior of Carbon Steel and Hot Dip Galvanized Steel in Simulated Concrete Solution with Different pH Values

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    Wanchen XIE

    2017-08-01

    Full Text Available Hot dip galvanizing technology is now widely used as a method of protection for steel rebars. The corrosion behaviors of Q235 carbon steel and hot galvanized steel in a Ca(OH2 solution with a pH from 10 to 13 was investigated by electrode potential and polarization curves testing. The results indicated that carbon steel and hot galvanized steel were all passivated in a strong alkaline solution. The electrode potential of hot dip galvanized steel was lower than that of carbon steel; thus, hot dip galvanized steel can provide very good anodic protection for carbon steel. However, when the pH value reached 12.5, a polarity reversal occurred under the condition of a certain potential. Hot dip galvanized coating became a cathode, and the corrosion of carbon steel accelerated. The electrochemical behaviors and passivation abilities of hot dip galvanized steel and carbon steel were affected by pH. The higher the pH value was, the more easily they were passivated.DOI: http://dx.doi.org/10.5755/j01.ms.23.3.16675

  9. Morphology and antimony segregation of spangles on batch hot-dip galvanized coatings

    Energy Technology Data Exchange (ETDEWEB)

    Peng Shu, E-mail: shu.peng@mail.scut.edu.cn [School of Materials Science and Engineering, South China University of Technology, No. 371 Wushan Road, Tianhe District, Guangzhou 510640 (China); Lu Jintang; Che Chunshan; Kong Gang; Xu Qiaoyu [School of Materials Science and Engineering, South China University of Technology, No. 371 Wushan Road, Tianhe District, Guangzhou 510640 (China)

    2010-06-01

    Spangles produced by batch hot-dip galvanizing process have a rougher surface and a greater surface segregation of alloying element compared with those in continuous hot-dip galvanizing line (CGL), owing to the cooling rate of the former is much smaller than that of the later. Therefore, typical spangles on a batch hot-dipped Zn-0.05Al-0.2Sb alloy coating were investigated. The chemical, morphological characterization and identification of the phases on the spangles were examined by scanning electron microscopy (SEM), backscattered electron imaging (BSE), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS) and X-ray diffraction analysis (XRD). The results showed that the coating surface usually exhibited three kinds of spangles: shiny, feathery and dull spangle, of which extensively antimony surface segregation was detected. The nature of precipitate on the coating surface was identified as {beta}-Sb{sub 3}Zn{sub 4}, The precipitated {beta}-Sb{sub 3}Zn{sub 4} particles distributed randomly on the shiny spangle surface, both {beta}-Sb{sub 3}Zn{sub 4} particles and dentritic segregation of antimony dispersed in the dendritic secondary arm spacings of the feathery spangle and on the whole dull spangle surface. The dentritic segregation of antimony and precipitation of Sb{sub 3}Zn{sub 4} compound are discussed by a proposed model.

  10. Effect of chemical composition of steel on the structure of hotdip galvanized coating

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    P. Pokorny

    2016-01-01

    Full Text Available This article describes the effect of the content of conventional steel impurity elements on the thickness and composition of the zinc layer. This article is focused primarily on low-temperature, batch hot-dip galvanizing; however, the continuous coating process is also mentioned. The main discussion covers galvanizing from pure zinc melt, and only touches on galvanizing from melts with the usual amounts of aluminium (0,2 wt. %. Silicon, phosphorus, aluminium and sulfur may have an especially negative effect on the mechanical properties of the coating and its final appearance. The content of ballast carbon and manganese has a rather limited effect on composition and coating thickness.

  11. Effect of Mg on the Microstructure and Corrosion Resistance of the Continuously Hot-Dip Galvanizing Zn-Mg Coating

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    Anping Dong

    2017-08-01

    Full Text Available The microstructure of continuously hot-dip galvanizing Zn-Mg coating was investigated in order to obtain the mechanism of the effects of Mg on the corrosion resistance. In this paper, the vertical section of the Zn-0.20 wt % Al-Mg ternary phase diagram near the Al-low corner was calculated. The results indicates that the phase composition of the Zn-0.20 wt % Al-Mg ternary phase diagram near the Al-low corner is the same as Zn-Mg binary phase diagram, suggesting Al in the Zn-Mg (ZM coatings mainly concentrates on the interfacial layer between the coating and steel substrate. The microstructure of continuously hot-dip galvanizing ZM coatings with 0.20 wt % Al containing 1.0–3.0 wt % Mg was investigated using tunneling electron microscopy (TEM. The morphology of Zn in the coating changes from bulk to strip and finally to mesh-like, and the MgZn2 changes from rod-like to mesh-like with the Mg content increasing. Al in the ZM coatings mainly segregates at the Fe2Al5 inhibition layer and the Mg added to the Zn bath makes this inhibition layer thinner and uneven. Compared to GI coating, the time of the first red rust appears increases by more than two-fold and expansion rate of red rust reduces by more than four-fold in terms of salt spray experiment. The ZM coating containing 2.0 wt % Mg has the best corrosion resistance. The enhanced corrosion resistance of ZM coatings mainly depends on different corrosion products.

  12. Nanoscale surface analysis on second generation advanced high strength steel after hot dip galvanizing.

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    Arndt, M; Duchoslav, J; Preis, K; Samek, L; Stifter, D

    2013-09-01

    Second generation advanced high strength steel is one promising material of choice for modern automotive structural parts because of its outstanding maximal elongation and tensile strength. Nonetheless there is still a lack of corrosion protection for this material due to the fact that cost efficient hot dip galvanizing cannot be applied. The reason for the insufficient coatability with zinc is found in the segregation of manganese to the surface during annealing and the formation of manganese oxides prior coating. This work analyses the structure and chemical composition of the surface oxides on so called nano-TWIP (twinning induced plasticity) steel on the nanoscopic scale after hot dip galvanizing in a simulator with employed analytical methods comprising scanning Auger electron spectroscopy (SAES), energy dispersive X-ray spectroscopy (EDX), and focused ion beam (FIB) for cross section preparation. By the combination of these methods, it was possible to obtain detailed chemical images serving a better understanding which processes exactly occur on the surface of this novel kind of steel and how to promote in the future for this material system galvanic protection.

  13. Simple Heat Treatment for Production of Hot-Dip Galvanized Dual Phase Steel Using Si-Al Steels

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    Equihua-Guillén, F.; García-Lara, A. M.; Muñíz-Valdes, C. R.; Ortíz-Cuellar, J. C.; Camporredondo-Saucedo, J. E.

    2014-01-01

    This work presents relevant metallurgical considerations to produce galvanized dual phase steels from low cost aluminum-silicon steels which are produced by continuous strip processing. Two steels with different contents of Si and Al were austenized in the two-phase field ferrite + austenite (α + γ) in a fast manner to obtain dual phase steels, suitable for hot-dip galvanizing process, under typical parameters of continuous annealing processing line. Tensile dual phase properties were obtained from specimens cooled from temperature below Ar3, held during 3 min, intermediate cooling at temperature above Ar1 and quenching in Zn bath at 465 °C. The results have shown typical microstructure and tensile properties of galvanized dual phase steels. Finally, the synergistic effect of aluminum, silicon, and residual chromium on martensite start temperature ( M s), critical cooling rate ( C R), volume fraction of martensite, and tensile properties has been studied.

  14. Local strain energy density for the fatigue assessment of hot dip galvanized welded joints: some recent outcomes

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    M. Peron

    2017-10-01

    Full Text Available Since in literature only data about the effect of the hot-dip galvanizing coating on fatigue behavior of unnotched specimens are available, whereas very few for notched components and none for welded joints, the aim of this paper is to partially fill this lack of knowledge comparing fatigue strength of uncoated and hot-dip galvanized fillet welded cruciform joints made of structural steel S355 welded joints, subjected to a load cycle R = 0. 34. The results are shown in terms of stress range ?s and of the averaged strain energy density range DW in a control volume of radius R0 = 0.28 mm

  15. Numerical Analysis of Edge Over Coating and Baffle Effect on Hot-Dip Galvanizing

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    Bao, Chengren; Kang, Yonglin; Li, Yan

    2017-06-01

    In hot-dip galvanizing process, air jet wiping control is so crucial to determine the coating thickness and uniformity of the zinc layer on the steel strip. A numerical simulation of gas-jet wiping in hot-dip galvanizing was conducted to minimize the occurrence of edge over coating (EOC). The causes of EOC were identified by contrasting and analyzing the airflow fields on the strip edge with and without a baffle. The factors influencing the airflow field on the strip edge during the change in the gap between the baffle and the strip edge were also analyzed. The effect of the distance between the air knife and the strip was evaluated. Technological parameters with on-site guidance role were obtained by combining them with the actual production to elucidate the role of the baffle in restraining the occurrence of EOC. The uniform distribution of pressure and coating thickness on the strip is achieved when the distance of the baffle from the strip edge is about 0.3 times of the jetting distance.

  16. Diversification of Intermetallic Zn Phases Growth on Steel During Hot-Dip Galvanizing

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    Węgrzynkiewicz S.

    2016-06-01

    Full Text Available The steel substrate formed as the result of oxy-acetylene cutting (OAB was treated differently - using: softening annealing, grinding and electro-polishing. Investigations were focused on the influence of additional processing on the structure and corrosion resistance of the deposited zinc coating. The hot - dip Zn galvanizing process was conducted in industrial conditions. Parameters were fixed: temperature 457 °C, dipping time 150 s. The coating thickness diversification dependent on the sub-surface steel structure was analysed and compared to the previous results. The correlation between conducted treatment and coatings morphology was determined.

  17. Effect of the Surface Layer of Iron Casting on the Growth of Protective Coating During Hot-Dip Galvanizing

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    Kopyciński D.

    2016-03-01

    Full Text Available The paper presents the results of investigations of the growth of protective coating on the surface of ductile iron casting during the hot-dip galvanizing treatment. Ductile iron of the EN-GJS-600-3 grade was melted and two moulds made by different technologies were poured to obtain castings with different surface roughness parameters. After the determination of surface roughness, the hot-dip galvanizing treatment was carried out. Based on the results of investigations, the effect of casting surface roughness on the kinetics of the zinc coating growth was evaluated. It was found that surface roughness exerts an important effect on the thickness of produced zinc coating.

  18. Effect of hot dip galvanization on the fatigue strength of steel bolted connections

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    S.M.J. Razavi

    2017-07-01

    Full Text Available Hot dip galvanized steel bolted joints has been tested under fatigue loading to evaluate the effect of galvanizing coating on the fatigue strength of S355 structural steel. The experimental results showed that the decrease of the fatigue life of coated specimens in comparison with that of uncoated joints is very limited and the results are in good agreement with Eurocode detail category, without substantial reductions. The procedure for coating and preparation of the bolted joints is described in detail in this paper providing a useful tool for engineers involved in similar practical applications. The experimental results are compared with the previously published data on central hole notched galvanized and not treated specimens characterized by the same geometry.

  19. Tribology and Tool Wear of Hot Dip Galvanized Zinc Magnesium Alloys on Cold Rolled Steel Sheets

    International Nuclear Information System (INIS)

    Raab, A. E.; Berger, E.; Freudenthaler, J.; Leomann, F.; Walch, C.

    2011-01-01

    Recently zinc based coatings on cold rolled steel with improved functionality in terms of forming and/or corrosion behaviour have been intensively investigated in the steel industry. One of the most promising products are zinc magnesium alloys produced in hot dip galvanizing process. These coatings were already introduced in construction industry a few years ago. With some modifications the improved properties of the coating are also interesting for automotive industry. In the present work the tribological potential of hot dip galvanized zinc magnesium coatings (HDG/ZM) produced at an industrial line under regular production, was studied in terms of sliding properties, adhesive and abrasive tool wear.First a short introduction into surface morphology of HDG/ZM will be given. For the tribological characterization of the material, which is the main topic of the contribution, different tests were performed on hot dip galvanised zinc magnesium material and results were compared with classic hot dip galvanized zinc coating (HDG/Z). The investigations are mainly based on the strip draw test which allows the determination of the friction coefficient directly by using a constant contact pressure. Deep drawing property was tested by forming model cups. The abrasive tool wear was tested using a standard test for material used in automotive industry. The adhesive tool wear was investigated by characterizing the coating material transferred to the tool in the strip draw test.All performed tests show an improved drawability of HDG/ZM compared to classical HDG/Z reference material. However the most promising difference between HDG/ZM and HDG/Z is that galling was found to be less for HDG/ZM than for HDG/Z. Therefore HDG/ZM is an interesting system not only with respect to corrosion protection but also in terms of tribology and provides clear advantages in formability.

  20. Tribology and Tool Wear of Hot Dip Galvanized Zinc Magnesium Alloys on Cold Rolled Steel Sheets

    Science.gov (United States)

    Raab, A. E.; Berger, E.; Freudenthaler, J.; Leomann, F.; Walch, C.

    2011-05-01

    Recently zinc based coatings on cold rolled steel with improved functionality in terms of forming and/or corrosion behaviour have been intensively investigated in the steel industry1,2,3. One of the most promising products are zinc magnesium alloys produced in hot dip galvanizing process. These coatings were already introduced in construction industry a few years ago1. With some modifications the improved properties of the coating are also interesting for automotive industry. In the present work the tribological potential of hot dip galvanized zinc magnesium coatings (HDG/ZM) produced at an industrial line under regular production, was studied in terms of sliding properties, adhesive and abrasive tool wear. First a short introduction into surface morphology of HDG/ZM will be given. For the tribological characterization of the material, which is the main topic of the contribution, different tests were performed on hot dip galvanised zinc magnesium material and results were compared with classic hot dip galvanized zinc coating (HDG/Z). The investigations are mainly based on the strip draw test which allows the determination of the friction coefficient directly by using a constant contact pressure. Deep drawing property was tested by forming model cups. The abrasive tool wear was tested using a standard test for material used in automotive industry. The adhesive tool wear was investigated by characterizing the coating material transferred to the tool in the strip draw test. All performed tests show an improved drawability of HDG/ZM compared to classical HDG/Z reference material. However the most promising difference between HDG/ZM and HDG/Z is that galling was found to be less for HDG/ZM than for HDG/Z. Therefore HDG/ZM is an interesting system not only with respect to corrosion protection but also in terms of tribology and provides clear advantages in formability.

  1. Deformation and fatigue behavior of hot dip galvanized coatings

    International Nuclear Information System (INIS)

    Camurri, Carlos P.; Benavente, Raul G.; Roa, Isidoro S.; Carrasco, Claudia C.

    2005-01-01

    This paper reports on the results of a study of the effect of static and dynamic stresses on hot dip galvanized coatings on SAE 1020 steel substrates. Galvanizing was performed using baths maintained at 450 deg. C, the zinc containing 0.16% Ti and 0.02% Fe and with Al and Ni in the ranges 0-0.20% and 0-0.30%, respectively. Static three-point bend tests were conducted with applied stresses in the range 428-790 MPa. Dynamic bend-fatigue tests involved stresses in the range 228-578 MPa at a cyclic frequency of 0.25 Hz for up to 700 cycles. The total crack density in the coatings was measured before and after the tests using light optical and electron microscopy. The results showed that the crack density increased as the applied stress increased and crack propagation was promoted perpendicular to the substrate. The number of cycles had no effect on the crack density and propagation at stresses lower than 386 MPa. At higher stresses the number of applied cycles contributed only to crack propagation. It was concluded that the best bath composition for preventing fatigue crack propagation is one that minimized the formation of thinner brittle layers in the galvanized coatings

  2. ENVIRONMENTAL AND ECONOMIC ASPECTS OF ANTICORROSION PROTECTION BY HOT-DIP GALVANIZED METHOD REBARS IN CONCRETE

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    Hegyi Andreea

    2015-05-01

    Full Text Available The implementation of the sustainable development concept is nowadays a key issue in almost all human activities. For the constructions domain an European strategy has already been elaborated. Among its goals are also the use of long lasting materials and the reduction of repair costs. This paper presents an interdisciplinary study concerning the efficiency of the use of hot-dip galvanized rebar for concrete structures. Experimental results about corrosion kinetics of coated and usual steel reinforcement embedded in concrete, subjected to chlorine ions attack, are analyzed. Electrochemical methods as chronoamperometry and linear polarization have been used. Corrosion potential values recorded for galvanized steel embedded in concrete indicate an uncertain corrosion activation process up to a rate of 2.5 % calcium chloride relative to concrete. For rates of 5% CaCl2 and more the corrosion process is activated. For unprotected steel bars embedded in concrete the corrosion activation process started at all calcium chloride studied rates and higher corrosion potential values has been registered than for the hot-dip galvanized ones, at the same rates. Economical assessments have been done using entire lifetime cost analysis of the reinforced concrete structures. Despite that the hotdip galvanization is a rather expansive procedure, when taking into account the whole expected life span, the use of zinc coating proves to be efficient both from structural and financial approaches.

  3. Mechanism and prevention of edge over coating in continuous hot-dip galvanizing

    Energy Technology Data Exchange (ETDEWEB)

    Takeishi, Y.

    2000-11-01

    In order to clarify the mechanism of edge over coating (EOC) for continuous hot-dip galvanizing, a visualization test of the gas flow on strip and a cold model test to measure the profile of the coating thickness at the strip edge were carried out. Outward deflected gas flow was observed at the strip edge and EOC developed in the absence of gas wiping. With gas wiping, EOC developing below the wiping position is reduced by the impinging pressure of the gas wiping jet, and the film thickness becomes approximately uniform at the gas wiping position. However, upward of the gas wiping position. EOC increases again and the outward deflected gas flow on the strip edge sweeps the liquid film to the strip edge. EOC is considered to develop at the location where the dynamic pressure of the outward deflected gas flow balances with the surface tension. For the prevention of EOC, edge masking was devised and the effects which reduce EOC were measured in the cold model test and on a commercial line test. The edge mask which can be kept farther away from the strip edge is more effective for preventing EOC than the edge plates. The optimum dimension of the edge mask is 30mm in width and 75-100 mm in depth, and installing it at 4-10mm away from the strip edge is most effective. It was confirmed by the commercial line test that the edge mask can reduce EOC from 45% to less than 10%. (author)

  4. Influence of dipping time on cracking during bending of hot dip galvanized coatings with Sn and Ti contents

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    L. Zortea

    2010-10-01

    Full Text Available In the last years, the attention to environmental topics led a new approach solution in classical protection techniques, introducing innovative way oriented to optimize different coating properties. Hot-dip galvanizing is a classical process aimed to generate coatings on iron-based surfaces, used unchanged since 200 years: some chemical elements are added in the bath with different aims (e.g., Pb is really important for its fluidizing properties, sometimes replaced by Sn but sometimes these elements are dangerous for human health (e.g. … Pb!.In this work, the influence of dipping time and coatings chemical compositions on damaging micromechanisms was investigated considering different Sn and Ti contents. Main damaging micromechanisms in hot dip zinc coated ipersandelin steel specimens were investigated by means of bending tests. Longitudinal sections of bended specimens were observed by means of a LOM (Light Optical Microscope: main damage micromechanisms were identified as longitudinal and radial cracks.

  5. Effect of confinement on bond strength of hot-dip galvanized lap splices in concrete structures

    International Nuclear Information System (INIS)

    Fakhran, Mazen

    2004-01-01

    Galvanizing the reinforcing steel is one of the methods used to protect bars against corrosion. Galvanizing is a hot dip process where the reinforcing bars are immersed in an aqueous pre flux solution of zinc ammonium chloride at a controlled temperature between 840 and 850 degrees F. In 2001, a research program was started at AUB to evaluate experimentally the effect of hot dip galvanizing on the bond capacity of tension lap splices anchored in full-scale beam specimens designed to fail in bond splitting mode. The test results indicated that the use of galvanized bars had a negligible effect on bond strength of reinforcement in normal strength. However, galvanizing caused an average of 20 percent decrease in bond strength of reinforcement in high strength concrete. The primary objective of research reported in this thesis, is the need to find a solution to eliminate the bond reduction of galvanized bars in high strength concrete. It is significant to evaluate the positive effect of the addition of transverse reinforcement in the splice region. The hypothesis to be tested is that such transverse reinforcement will insure uniform bond stress distribution over the entire splice region, thus mobilizing all bar lugs along the splice in the stress transfer mechanism between the bar and the surrounding concrete. Such mechanism might reduce the significant decrease in bond strength in high strength concrete due to galvanizing. To achieve this objective, eighteen full-scale beam specimens were tested in positive bending. Each beam was reinforced with bars spliced in a constant moment region at midspam. The splice length was chosen in such a way that the beams failed in bond splitting of the concrete cover in the splice region. The main variables were type of coating (black or galvanized bars), bar size (20, 25 and 32 mm), and amount of transverse reinforcement in the splice region (0, 2 or 4 stirrups). The test results indicated that confinement did not have a significant

  6. Nanoscale analysis of the influence of pre-oxidation on oxide formation and wetting behavior of hot-dip galvanized high strength steel

    International Nuclear Information System (INIS)

    Arndt, M.; Duchoslav, J.; Steinberger, R.; Hesser, G.; Commenda, C.; Samek, L.; Arenholz, E.

    2015-01-01

    Highlights: • Pre-oxidized hot-dip galvanized advanced high strength steel was examined. • The interface was analyzed in detail via high energy resolution Auger spectra. • Evidence for an aluminothermic reduction of the Mn oxide was found. • A new model for galvanizing high manganese steel was developed. - Abstract: Hot-dip galvanized (HDG) 2nd generation advanced high strength steel (AHSS), nano-TWIP (twinning induced plasticity) with 15.8 wt.% Mn, 0.79 wt.% C, was analyzed at the interface between steel and zinc by scanning Auger electron microscopy (AES) in order to confirm and improve an existing model of additional pre-oxidation treatment before annealing and immersion into the hot zinc bath. Furthermore these steel samples were fractured in the analysis chamber of the AES and analyzed without breaking vacuum. In these measurements the results of an aluminothermic reduction of the manganese and iron surface oxides on the steel could be confirmed by AES

  7. The effect of immersion time to low carbon steel hardness and microstructure with hot dip galvanizing coating method

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    Hakim, A. A.; Rajagukguk, T. O.; Sumardi, S.

    2018-01-01

    Along with developing necessities of metal materials, these rise demands of quality improvements and material protections especially the mechanical properties of the material. This research used hot dip galvanizing coating method. The objectives of this research were to find out Rockwell hardness (HRb), layer thickness, micro structure and observation with Scanning Electron Microscope (SEM) from result of coating by using Hot Dip Galvanizing coating method with immersion time of 3, 6, 9, and 12 minutes at 460°C. The result shows that Highest Rockwell hardness test (HRb) was at 3 minutes immersion time with 76.012 HRb. Highest thickness result was 217.3 μm at 12 minutes immersion. Microstructure test result showed that coating was formed at eta, zeta, delta and gamma phases, while Scanning Electron Microscope (SEM) showed Fe, Zn, Mn, Si and S elements at the specimens after coating.

  8. Description of structure of Fe-Zn intermetalic compounds present in hot-dip galvanized coatings on steel

    Directory of Open Access Journals (Sweden)

    P. Pokorny

    2015-10-01

    Full Text Available The article is describing formation, composition, morphology and crystallographic characteristics of intermetalic compounds Fe - Zn present in the coating formed during the process of low-temperature hot-dip galvanizing of carbon steels. In mutual confrontation we introduce older bibliography and results of latest modern researches based on combination of most precise analytical methods.

  9. The effect of zinc bath temperature on the morphology, texture and corrosion behaviour of industrially produced hot-dip galvanized coatings

    Directory of Open Access Journals (Sweden)

    A. Bakhtiari

    2014-03-01

    Full Text Available The purpose of this work is to identify the influence of zinc bath temperature on the morphology, texture and corrosion behavior of hot-dip galvanized coatings. Hot-dip galvanized samples were prepared at temperature in the range of 450-480 °C in steps of 10 °C, which is the conventional galvanizing temperature range in the galvanizing industries. The morphology of coatings was examined with optical microscopy and scanning electron microscopy (SEM. The composition of the coating layers was determined using energy dispersive spectroscopy (EDS analysis. The texture of the coatings was evaluated using X-ray diffraction. Corrosion behavior was performed using salt spray cabinet test and Tafel extrapolation test. From the experimental results, it was found that increasing the zinc bath temperature affects the morphology of the galvanized coatings provoking the appearance of cracks in the coating structure. These cracks prevent formation of a compact structure. In addition, it was concluded that (00.2 basal plane texture component was weakened by increasing the zinc bath temperature and, conversely, appearance of (10.1 prism component, (20.1 high angle pyramidal component and low angle component prevailed. Besides, coatings with strong (00.2 texture component and weaker (20.1 components have better corrosion resistance than the coatings with weak (00.2 and strong (20.1 texture components. Furthermore, corrosion resistance of the galvanized coatings was decreased by increasing the zinc bath temperature.

  10. Report on best available techniques (BAT) at Finnish hot dip galvanizing plants in 2001; Selvitys parhaasta kaeytettaevissae olevasta tekniikasta (BAT) Suomen kuumasinkityslaitoksissa vuonna 2001

    Energy Technology Data Exchange (ETDEWEB)

    Hakala, I.

    2002-02-01

    Report presents hot dip (batch) galvanizing process and its emissions as well as measures to prevent and control them. Report has been prepared in cooperation with industry representatives and environmental authorities. Reference Document on Best Available Techniques in the Ferrous Metals Processing Industry and especially its part concerning batch galvanizing has been utilized. Also background information from the existing environmental permits as well as information collected by the questionnaires has been used. In year 2001 there were 18 hot dip (batch) galvanizing plants in Finland. Branch can be considered quite homogenous as there are only few variations in processes used. Waste management and recovery and as well as waste water treatment are well taken care of. At many plants treated process water is recycled back to the galvanizing process. Air emissions from hot dipping pot (dust, zinc, ammonium compounds, chlorides) are filtrated only at few plants. Therefore most of the environmental load at many plants is caused by air emissions as they can indirectly cause pollution also into soil and nearby water bodies. Instead of specific emission and consumption data and comparison between different techniques, report presents choice of measures and actions to be taken into account when applying best available techniques (BAT) at an installation level. Galvanizers can use the report as background information when assessing implementation of BAT at their own plants. Permitting authorities can utilize the report in the environmental permitting of the plants. (orig.)

  11. Effects of Niobium Microalloying on Microstructure and Properties of Hot-Dip Galvanized Sheet

    Energy Technology Data Exchange (ETDEWEB)

    Mohrbacher, Hardy [NiobelCon bvba, Brussels (Belgium)

    2010-04-15

    Niobium microalloying is effective in hot-rolled and cold-rolled steels by providing a fine-grained microstructure resulting in increased strength. To optimize the strengthening effect, alloy design and hot-rolling conditions have to be adapted. As a key issue the dissolution and precipitation characteristics of Nb are discussed in particular with regard to the run-out table conditions. It is then considered how the hot-rolled microstructure and the solute state of Nb interact with the hot-dip galvanizing cycle. The adjusted conditions allow controlling the morphology and distribution of phases in the cold-rolled annealed material. Additional precipitation hardening can be achieved as well. The derived options can be readily applied to produce conventional HSLA and IF high strength steels as well as to modem multiphase steels. It will be explained how important application properties such as strength, elongation, bendability, weldability and delayed cracking resistance can be influenced in a controlled and favorable way. Examples of practical relevance and experience are given.

  12. Development of Continuous Galvanization-compatible Martensitic Steel

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Y. F.; Song, T. J.; Kim, Han S.; De Cooman [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of); Kwak, J. H. [POSCO Gwangyang Works, Gwangyang (Korea, Republic of)

    2012-01-15

    The development of martensitic grades which can be processed in continuous galvanizing lines requires the reduction of the oxides formed on the steel during the hot dip process. This reduction mechanism was investigated in detail by means of High Resolution Transmission Electron Microscopy (HR-TEM) of cross-sectional samples. Annealing of a martensitic steel in a 10% H{sub 2} + N{sub 2} atmosphere with the dew point of -35 .deg. C resulted in the formation of a thin c-xMno.SiO{sub 2} (x>1) oxide film and amorphous a-xMnO.SiO{sub 2} oxide particles on the surface. During the hot dip galvanizing in Zn-0.13%Al, the thin c-xMnO.SiO{sub 2} (x>1) oxide films was reduced by the Al. The a-xMnO.SiO{sub 2} (x<0.9) and a-SiO{sub 2} (x>1) oxide film was also reduced and the amorphous a-xMnO.SiO{sub 2} and a-SiO{sub 2} particles were embedded in the Fe{sub 2}Al{sub 5-x}Zn{sub x} inhibition layer formed at the steel/coating interface during hot dipping. The results clearly show that Al in the liquid Zn bath can reduce the crystalline c-xMn.SiO{sub 2} (x>1) oxides but not the amorphous a-xMnO.SiO{sub 2} (x<0.9) and a-SiO{sub 2} oxides. These oxides remain embedded in the Zn layer or in the inhibition layer, making it possible to apply a Zn or Zn-alloy coating on martensitic steel by hot dipping. The hot dipping process was also found to deteriorate the mechanical properties, independently of the Zn bath composition.

  13. Characterization of solid wastes from two different hot-dip galvanizing processes; Caracterizacion de residuos solidos procedentes de dos procesos distintos de galvanizado en caliente por inmersion

    Energy Technology Data Exchange (ETDEWEB)

    Delvasto, P.; Casal-Ramos, J. a.; Gonzalez-Jordan, O.; Duran-Rodriguez, N. C.; Dominguez, J. R.; Moncada, P.

    2012-11-01

    Zinc dust and zinc ash from hot-dip galvanizing industries located in Venezuela were characterized using atomic spectroscopy, scanning electron microscopy, X-Ray diffraction and infrared spectroscopy. Dust was formed during the high-pressure drying process of the galvanized pieces, in a plant that uses a steel kettle to hold the molten zinc. Ash identified as A came from the same plant as the dust, while ash identified as B came from a hot-dip galvanizing plant which use a ceramic lined galvanizing furnace. Dust contained 98 wt % Zn, in metallic form. Both ash samples contained: Zn and ZnO, while Zn{sub 5}(OH){sub 8}Cl{sub 2}×H{sub 2}O and ZnCl{sub 2} were only found in ash B. Globally, ash “A” and ash “B” contain 71 and 75 wt % Zn, respectively. (Author)

  14. Thermodynamic Study of the Nickel Addition in Zinc Hot-Dip Galvanizing Baths

    Science.gov (United States)

    Pistofidis, N.; Vourlias, G.

    2010-01-01

    A usual practice during zinc hot-dip galvanizing is the addition of nickel in the liquid zinc which is used to inhibit the Sandelin effect. Its action is due to the fact that the ζ (zeta) phase of the Fe-Zn system is replaced by the Τ (tau) phase of the Fe-Zn-Ni system. In the present work an attempt is made to explain the formation of the Τ phase with thermodynamics. For this reason the Gibbs free energy changes for Τ and ζ phases were calculated. The excess free energy for the system was calculated with the Redlich-Kister polyonyme. From this calculation it was deduced that the Gibbs energy change for the tau phase is negative. As a result its formation is spontaneous.

  15. Effect of Annealed Oxides on the Formation of Inhibition Layer During Hot-Dip Galvanizing of 590Mpa Trip Steel

    International Nuclear Information System (INIS)

    Kim, Seong Hwan; Huh, Joo Youl; Lee, Suk Kyu; Park, Rho Bum; Kim, Jong Sang

    2011-01-01

    The selective surface oxidation of a transformation-induced-plasticity (TRIP) steel containing 1.6 wt.% Mn and 1.5 wt.% Si during annealing at 800 .deg. C was investigated for its influence on the formation of an inhibition layer during hot-dip galvanizing. The selective oxidation of the alloying elements and the oxide morphology were significantly influenced by the annealing atmosphere. The pure N 2 atmosphere with a dew point -40 .deg. C promoted the selective oxidation of Mn as a crystalline Mn 2 SiO 4 phase, whereas the N 2 + 10% H 2 atmosphere with the same dew point -40 .deg. C promoted the selective oxidation of Si as an amorphous Si-rich oxide phase. During hot-dip galvanizing, the Mn 2 SiO 4 phase was reduced more readily by Al in the Zn bath than the Si-rich oxide phase. Consequently, the pure N 2 atmosphere resulted in a higher formation rate of Fe 2 Al 5 particles at the Zn/steel interface and better galvanizability than the N 2 + 10% H 2 atmosphere

  16. Designing the Color of Hot-Dip Galvanized Steel Sheet Through Destructive Light Interference Using a Zn-Ti Liquid Metallic Bath

    Science.gov (United States)

    Levai, Gabor; Godzsák, Melinda; Török, Tamas I.; Hakl, Jozsef; Takáts, Viktor; Csik, Attila; Vad, Kalman; Kaptay, George

    2016-07-01

    The color of hot-dip galvanized steel sheet was adjusted in a reproducible way using a liquid Zn-Ti metallic bath, air atmosphere, and controlling the bath temperature as the only experimental parameter. Coloring was found only for samples cooled in air and dipped into Ti-containing liquid Zn. For samples dipped into a 0.15 wt pct Ti-containing Zn bath, the color remained metallic (gray) below a 792 K (519 °C) bath temperature; it was yellow at 814 K ± 22 K (541 °C ± 22 °C), violet at 847 K ± 10 K (574 °C ± 10 °C), and blue at 873 K ± 15 K (600 °C ± 15 °C). With the increasing bath temperature, the thickness of the adhered Zn-Ti layer gradually decreased from 52 to 32 micrometers, while the thickness of the outer TiO2 layer gradually increased from 24 to 69 nm. Due to small Al contamination of the Zn bath, a thin (around 2 nm) alumina-rich layer is found between the outer TiO2 layer and the inner macroscopic Zn layer. It is proven that the color change was governed by the formation of thin outer TiO2 layer; different colors appear depending on the thickness of this layer, mostly due to the destructive interference of visible light on this transparent nano-layer. A complex model was built to explain the results using known relationships of chemical thermodynamics, adhesion, heat flow, kinetics of chemical reactions, diffusion, and optics. The complex model was able to reproduce the observations and allowed making predictions on the color of the hot-dip galvanized steel sample, as a function of the following experimental parameters: temperature and Ti content of the Zn bath, oxygen content, pressure, temperature and flow rate of the cooling gas, dimensions of the steel sheet, velocity of dipping the steel sheet into the Zn-Ti bath, residence time of the steel sheet within the bath, and the velocity of its removal from the bath. These relationships will be valuable for planning further experiments and technologies on color hot-dip galvanization of steel

  17. Problems with reliability and safety of hot dip galvanized steel structures Problemas com a confiabilidade e segurança de estruturas de aço galvanizadas a quente

    Directory of Open Access Journals (Sweden)

    L. Mraz

    2009-06-01

    Full Text Available Hot dip galvanizing is very effective means of protection against corrosion. Some recommendation concerning the steel quality are generally known and accepted. The process consists of cleaning (pickling or sand blasting and dipping the structures or pieces into liquid zinc bath. The case study of hot dip galvanized steels is presented. Some recent failures of hot dip galvanized welded structures and hot dip galvanized high strength steel screws are presented. Structures were made of S355 grade steel and MIG/MAG process was applied for welding. Large cracks were observed in the vicinity of welds after hot dip galvanizing process. The presence of both hydrogen and liquid metal embrittlement was identified and associated mainly with higher hardness of HAZ or the quenched and tempered steels. Possible cracking mechanisms are discussed. The influence of chemical composition and production process (welding, heat treatment was analyzed according to data published in literature. The solutions and recommendations for avoiding the failure in hot dip galvanized structures are proposed.Galvanização a quente é um meio muito efetivo de proteção contra a corrosão. Recomendações relativas a qualidade do aço são geralmente conhecidas e aceitas. O processo consiste de limpar (decapagem ou jateamento e mergulhar as estruturas ou partes destas em um banho de zinco líquido. O presente trabalho apresenta casos de falhas recentes em estruturas soldadas e em parafusos de aços de alta resistência galvanizados a quente. As estruturas foram fabricadas com aço do grau S355 e o processo MIG/MAG foi usado para a soldagem. Os parafusos foram fabricados com aço de alto carbono. Grandes trincas foram observadas nas proximidades das soldas após o processo de galvanização a quente. A ocorrência de fragilização tanto por hidrogênio como por metal líquido foi identificada e associada com a dureza elevada tanto da ZTA como dos aços temperados e revenidos. Os

  18. Surface conditioning of a cold-rolled dual-phase steel by annealing in nitriding atmospheres prior to hot-dip galvanizing

    Energy Technology Data Exchange (ETDEWEB)

    Luther, F.; Beste, D.; Bleck, W. [Institute for Ferrous Metallurgy (IEHK), RWTH Aachen (Germany); Dimyati, A.; Mayer, J. [Central Facility for Electron Microscopy (GFE), RWTH Aachen (Germany)

    2007-04-15

    The development of steel grades for automotive applications in the recent years has been driven on by two trends: lightweight and improved crash safety. By using steels like DP (dual phase) the goals of passenger safety, fuel efficiency and environmental friendliness can be met at reasonable price. The favorite corrosion protection method for sheet steels in the car industry is the hot-dip galvanizing process. Here, an approach was made to reduce the surface enrichment of critical alloying elements of a dual phase steel grade by reactive annealing in ammonia containing atmospheres. The effects of this treatment on mechanical properties and hot-dip coating behavior are reported. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  19. Effect of strip temperature on the formation of an Fe{sub 2}Al{sub 5} inhibition layer during hot-dip galvanizing

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Monojit [R and D Division, Tata Steel Ltd., Jamshedpur 831001 (India)], E-mail: monoron@yahoo.com; Singh, Shiv Brat [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur 721302 (India)

    2009-04-15

    The theory of nucleation has been employed to derive expressions for the formation of an Fe{sub 2}Al{sub 5} layer during commercial strip galvanizing. This is then used to show the effect of the strip entry temperature on the nucleation of the Fe{sub 2}Al{sub 5} layer. An attempt was also made to verify this effect through controlled experiments in a hot-dip galvanizing simulator and electron microscopic characterization of a few samples.

  20. Dissolution-Induced Nanowire Synthesis on Hot-Dip Galvanized Surface in Supercritical Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Aaretti Kaleva

    2017-07-01

    Full Text Available In this study, we demonstrate a rapid treatment method for producing a needle-like nanowire structure on a hot-dip galvanized sheet at a temperature of 50 °C. The processing method involved only supercritical carbon dioxide and water to induce a reaction on the zinc surface, which resulted in growth of zinc hydroxycarbonate nanowires into flower-like shapes. This artificial patina nanostructure predicts high surface area and offers interesting opportunities for its use in industrial high-end applications. The nanowires can significantly improve paint adhesion and promote electrochemical stability for organic coatings, or be converted to ZnO nanostructures by calcining to be used in various semiconductor applications.

  1. Research on the Microstructures and Mechanical Properties of Ti Micro-Alloyed Cold Rolled Hot-Dip Galvanizing DP980 Steel

    Science.gov (United States)

    Han, Yun; Kuang, Shuang; Qi, Xiumei; Xie, Chunqian; Liu, Guanghui

    Effects of galvanizing simulation parameters on microstructures and mechanical properties of Ti-microalloyed cold rolled hot-dip galvanizing DP980 steel were investigated in this study by optical microscopy (OM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and tensile test. Moreover, the precipitation behavior of Ti in the experimental steel was also studied. The results show that, as the heating temperature increases, the tensile strength of experimental galvanizing DP980 steel decreases while the yield ratio and elongation of the steel are enhanced. The microstructures of experimental steels exhibit typical dual phase steel character and the volume fractions of MA islands are almost 30%. In addition, lots of nano-sized TiC precipitates can be found in the ferrite grains.

  2. Factors affecting the hot-dip zinc coatings structure

    International Nuclear Information System (INIS)

    Sere, P.R.; Cuclcasi, J.D.; Elsner, C.I.; Sarli, A.R.

    1997-01-01

    Coating solidification during hot-dip galvanizing is a very complex process due to Al-Fe, Al-Fe-Zn and Fe-Zn intermetallic compounds development . Fe-Zn intermetallics are brittle and detrimental for the coating ductility, while the diffusion towards the surface of a segregated insoluble alloying such as antimonium causes the sheet darkness. Steel of different roughness were hot-dip galvanized under different operation conditions using a laboratory scale simulator. The effect of steel roughness and process parameters upon coating characteristics were analysed. Experimental results showed that the steel roughness affects the coating thickness, zinc grain size and texture as well as the out-bursts development, while the process parameters affects the Fe 2 Al 5 morphology and antimonium segregation. (Author) 11 refs

  3. Effect of Annealed Oxides on the Formation of Inhibition Layer During Hot-Dip Galvanizing of 590Mpa Trip Steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Hwan; Huh, Joo Youl [Korea University, Seoul (Korea, Republic of); Lee, Suk Kyu; Park, Rho Bum; Kim, Jong Sang [POSCO Technical Research Laboratories, Gwangyang (Korea, Republic of)

    2011-02-15

    The selective surface oxidation of a transformation-induced-plasticity (TRIP) steel containing 1.6 wt.% Mn and 1.5 wt.% Si during annealing at 800 .deg. C was investigated for its influence on the formation of an inhibition layer during hot-dip galvanizing. The selective oxidation of the alloying elements and the oxide morphology were significantly influenced by the annealing atmosphere. The pure N{sub 2} atmosphere with a dew point -40 .deg. C promoted the selective oxidation of Mn as a crystalline Mn{sub 2}SiO{sub 4} phase, whereas the N{sub 2} + 10% H{sub 2} atmosphere with the same dew point -40 .deg. C promoted the selective oxidation of Si as an amorphous Si-rich oxide phase. During hot-dip galvanizing, the Mn{sub 2}SiO{sub 4} phase was reduced more readily by Al in the Zn bath than the Si-rich oxide phase. Consequently, the pure N{sub 2} atmosphere resulted in a higher formation rate of Fe{sub 2}Al{sub 5} particles at the Zn/steel interface and better galvanizability than the N{sub 2} + 10% H{sub 2} atmosphere.

  4. An evaluation of airborne nickel, zinc, and lead exposure at hot dip galvanizing plants.

    Science.gov (United States)

    Verma, D K; Shaw, D S

    1991-12-01

    Industrial hygiene surveys were conducted at three hot dip galvanizing plants to determine occupational exposure to nickel, zinc, and lead. All three plants employed the "dry process" and used 2% nickel, by weight, in their zinc baths. A total of 32 personal and area air samples were taken. The air samples were analyzed for nickel, zinc, and lead. Some samples were also analyzed for various species of nickel (i.e., metallic, soluble, and oxidic). The airborne concentrations observed for nickel and its three species, zinc, and lead at the three plants were all well below the current and proposed threshold limit values recommended by the American Conference of Governmental Industrial Hygienists (ACGIH).

  5. Stabilization/solidification of hot dip galvanizing ash using different binders.

    Science.gov (United States)

    Vinter, S; Montanes, M T; Bednarik, V; Hrivnova, P

    2016-12-15

    This study focuses on solidification of hot dip-galvanizing ash with a high content of zinc and soluble substances. The main purpose of this paper is to immobilize these pollutants into a matrix and allow a safer way for landfill disposal of that waste. Three different binders (Portland cement, fly ash and coal fluidized-bed combustion ash) were used for the waste solidification. Effectiveness of the process was evaluated using leaching test according to EN 12457-4 and by using the variance analysis and the categorical multifactorial test. In the leaching test, four parameters were observed: pH, zinc concentration in leachate, and concentration of chlorides and dissolved substances in leachate. The acquired data was then processed using statistical software to find an optimal solidifying ratio of the addition of binder, water, and waste to the mixture, with the aim to fulfil the requirement for landfill disposal set by the Council Decision 2003/33/EC. The influence on the main observed parameters (relative amount of water and a binder) on the effectiveness of the used method and their influence of measured parameters was also studied. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Effect of Annealing Temperature on Microstructure and Mechanical Properties of Hot-Dip Galvanizing DP600 Steel

    Science.gov (United States)

    Hai-yan, Sun; Zhi-li, Liu; Yang, Xu; Jian-qiang, Shi; Lian-xuan, Wang

    Hot-dip galvanizing dual phase steel DP600 steel grade with low Si was produced by steel plant and experiments by simulating galvanizing thermal history. The microstructure was observed and analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of different annealing temperatures on the microstructure and mechanical properties of dual-phase steel was also discussed. The experimental results show that the dual-phase steel possesses excellent strength and elongation that match EN10346 600MPa standards. The microstructure is ferrite and martensite. TEM micrograph shows that white ferrite with black martensite islands inlay with a diameter of around 1um and the content of 14 18%. The volume will expand and phase changing take the form of shear transformation when ferrite converted to martensite. So there are high density dislocations in ferrite crystalline grain near martensite. The martensite content growing will be obvious along with annealing temperature going up. But the tendency will be weak when temperature high.

  7. Microstructure development and mechanical properties of quenching and partitioning (Q and P) steel and an incorporation of hot-dipping galvanization during Q and P process

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jing; Yu, Hao, E-mail: yhzhmr@126.com

    2013-12-01

    The “quenching and partitioning” (Q and P) process has recently been substantiated to be a unique technological route for the production of high strength steels with significant amounts of retained austenite, and thus to provide better combination of strength and ductility. In this work, intercritically annealed specimens followed by Q and P treatment have been applied to low-carbon steel with chemical composition typical for conventional TRIP-assisted steels. Microstructure of the steel treated by the Q and P process was characterized by means of optical microscope, SEM, TEM and XRD. The study suggests that microstructure is mainly composed of ferrite, lath martensite, martensite–austenite islands, retained austenite and a small amount of bainite formed during partitioning. The fraction of bainite formed during partitioning is proportional to quenching temperature. The mechanical property of specimen treated by the Q and P process exhibits an improved combination of strength and ductility than that of the Q and T process. Two schemes of hot-dipping galvanization processes were designed. The results indicate that both hot-dip galvanizing schemes present a limited reduction in tensile strength and a slight enhancement of ductility. The scheme of galvanizing and partitioning after the quenching progress shows a better combination of strength and ductility.

  8. Influence of some additives to the kinetics of Zn-crystal growth onto continuous hot dip galvanized steel

    International Nuclear Information System (INIS)

    Arsovski, Angel; Sekuloski, Predrag; Georgievski, Mile; Mickovski, Jovan

    2003-01-01

    In this work we made attempt on determination of the gefree, of influence, of the different types of additives on zinc spangle growth during forming of zinc coating, at the process of continues hot deep galvanizing of steel strip. All investigations were made at cold rolling mill plant 'Ladna Valavnica'-Skopje - HDG line, Additives were implied manually using hand pump directly on full hard strip, just before annealing furnace. Three types of additives were used in unchanged state as well as their mixtures. Analysis of the results included macro photograph of the surface, microphotograph of the zinc coating as well as different attempts of mathematical models. During investigation all technological parameters (cleanness of the strip from the emulsion marks, temperatures of the different zones of the furnace, temperature of the molten zinc and chemical composition of the zinc pot) remained at their constant values. (Original)

  9. Performance of Flow and Heat Transfer in a Hot-Dip Round Coreless Galvanizing Bath

    Science.gov (United States)

    Yue, Qiang; Zhang, Chengbo; Xu, Yong; Zhou, Li; Kong, Hui; Wang, Jia

    2017-04-01

    Flow field in a coreless hot-dip galvanizing pot was investigated through a water modeling experiment. The corresponding velocity vector was measured using an acoustic Doppler velocimeter. The flow field of molten zinc in the bath was also analyzed. Steel strip velocities from 1.7 to 2.7 m/s were adopted to determine the effect of steel strip velocity on the molten zinc flow in the bath. A large vortex filled the space at the right side of the sink roll, under linear speed from 1.0 to 2.7 m/s and width from 1.0 to 1.3 m of the steel strip, because of the effects of wall and shear stress. The results of the water modeling experiment were compared with those of numerical simulations. In the simulation, Maxwell equations were solved using finite element method to obtain magnetic flux density, electromagnetic force, and Joule heating. The Joule heating rate reached the maximum and minimum values near the side wall and at the core of the bath, respectively, because of the effect of skin and proximity. In an industrial-sized model, the molten zinc flow and temperature fields driven by electromagnetic force and Joule heating in the inductor of a coreless galvanizing bath were numerically simulated. The results indicated that the direction of electromagnetic force concentrated at the center of the galvanizing pot horizontal planes and exerted a pinch effect on molten zinc. Consequently, molten zinc in the pot was stirred by electromagnetic force. Under molten zinc flow and electromagnetic force stirring, the temperature of the molten zinc became homogeneous throughout the bath. This study provides a basis for optimizing electromagnetic fields in coreless induction pot and fine-tuning the design of steel strip parameters.

  10. In Situ Apparatus to Study Gas-Metal Reactions and Wettability at High Temperatures for Hot-Dip Galvanizing Applications

    Science.gov (United States)

    Koltsov, A.; Cornu, M.-J.; Scheid, J.

    2018-02-01

    The understanding of gas-metal reactions and related surface wettability at high temperatures is often limited due to the lack of in situ surface characterization. Ex situ transfers at low temperature between annealing furnace, wettability device, and analytical tools induce noticeable changes of surface composition distinct from the reality of the phenomena.Therefore, a high temperature wettability device was designed in order to allow in situ sample surface characterization by x-rays photoelectron spectroscopy after gas/metal and liquid metal/solid metal surface reactions. Such airless characterization rules out any contamination and oxidation of surfaces and reveals their real composition after heat treatment and chemical reaction. The device consists of two connected reactors, respectively, dedicated to annealing treatments and wettability measurements. Heat treatments are performed in an infrared lamp furnace in a well-controlled atmosphere conditions designed to reproduce gas-metal reactions occurring during the industrial recrystallization annealing of steels. Wetting experiments are carried out in dispensed drop configuration with the precise control of the deposited droplets kinetic energies. The spreading of drops is followed by a high-speed CCD video camera at 500-2000 frames/s in order to reach information at very low contact time. First trials have started to simulate phenomena occurring during recrystallization annealing and hot-dip galvanizing on polished pure Fe and FeAl8 wt.% samples. The results demonstrate real surface chemistry of steel samples after annealing when they are put in contact with liquid zinc alloy bath during hot-dip galvanizing. The wetting results are compared to literature data and coupled with the characterization of interfacial layers by FEG-Auger. It is fair to conclude that the results show the real interest of such in situ experimental setup for interfacial chemistry studies.

  11. Analysis Of Effect Of Mechanical Properties Of Aluminum Alloy Addition Of Zinc Corrosion Resistance Of Carbon Steel A325 Bolts Process Of Hot Dip Galvanizing

    Directory of Open Access Journals (Sweden)

    Ery Diniardi

    2015-08-01

    Full Text Available The world oil industry are common in offshore areas that are included in a corrosive environment so that the low-carbon steel bolts A325 will gradually corroded. Therefore an alternative that can be done to reduce the corrosion rate that is by coating with a Hot dip galvanizing method. The purpose of this study to improve the quality of products from low carbon steel bolts A325 with the addition of Zinc Aluminium alloy on the results of the Hot Dip Galvanizing. Results of testing the hardness of the lowest obtained in quenching time of 30 seconds is 162 037 HVN and the highest hardness obtained on quenching time of 60 seconds is 203 688 HVN. To microstructure shows that the phase Eta which is soft on the surface of the outermost started a little not as much time quenching 30 seconds so that the nature of its decline and violence increased the phase Zeta that are hard are widely spread meet the layer of phase resulting in hardness of the coating while quenching 45 seconds exceed the hardness of quenching time of 30 seconds. Results of analysis of the rate of corrosion that galvanized coating on each test is different and the structure of ferrite and pearlite it looks clear. For quenching time of 30 seconds obvious difference in galvanized layer thicker than quenching time of 45 and 60 seconds. This happens because of the influence of factors zinc layer that coats the base material so that decreased levels of corrosion is comparable to the time Salt Spray Test SST performed.

  12. A suggestion of a new method for the calculation of the coating thickness in continuous hot-dip galvanizing

    Energy Technology Data Exchange (ETDEWEB)

    Jo, C. M.; Kwon, Y. D.; Kwon, S. B. [Kyungpook National University, Daegu (Korea, Republic of); Kim, G. Y. [POSCO Technical Research laboratories, Gumgo-dong (Korea, Republic of)

    2011-11-15

    It is known that the distributions of the impinging pressure gradient and the shear stress at the strip surface play a decisive key role in the decision of the coating thickness in hot-dip galvanizing. So, to predict the exact coating thickness, it is essential that the distributions of the impinging wall jet pressure and the shear stress acting between the liquid film and jet stream are measured (or calculated) exactly for each specific coating condition. So far, to obtain the impinging wall jet pressure, it was assumed that the jet issuing from an air-knife is similar to the Hiemenz plane stagnation flow, and the wall shear stress could be predicted by an equation using the assumption of a non-negative Gaussian profile in impinging wall jet pressure in general, so that it cannot be reliable for some impinging wall jet regions and nozzle systems intrinsically. Nevertheless, one cannot find a suitable method to cope with the difficulties in measuring/calculating of the shear stress and the impinging wall jet pressure. Such a difficulty which will cause an inaccuracy in the coating thickness prediction. With these connections, in the present study, we suggest a new method named as a two-step calculation method to calculate the final coating thickness, which consists of the air jet analysis and coating thickness calculation. And, from the comparison of the results one may confirm the validation of the new suggested method.

  13. A study of the influence of air-knife tilting on coating thickness in hot-dip galvanizing

    Science.gov (United States)

    Cho, Tae-Seok; Kwon, Young-Doo; Kwon, Soon-Bum

    2009-09-01

    Gas wiping is a decisive operation in hot-dip galvanizing process. In special, it has a crucial influence on the thickness and uniformity in coating film, but may be subsequently responsible for the problem of splashing. The progress of industry demands continuously the reduction of production costs which may relate directly with the increase of coating speed, and the speed up of coating results in the increase of stagnation pressure in gas wiping system in final. It is known that the increase of stagnation pressure may accompany a harmful problem of splashing in general. Together with these, also, from the view point of energy consumption, it is necessary to design a nozzle optimally. And there is known that the downward tilting of nozzle using in air knife system is effective to prevent in somewhat the harmful problem of splashing. In these connections, first, we design a nozzle with constant expansion rate. Next, for the case of actual coating conditions in field, the effects of tilting of the constant expansion rate nozzle are investigated by numerical analysis. Under the present numerical conditions, it was turned out that the nozzle of constant expansion rate of p = having a downward jet angle of 5° is the most effective to diminish the onset of splashing, while the influence of small tilting of the nozzle on impinging wall pressure itself is not so large.

  14. Relation between microstructure and adhesion of hot dip galvanized zinc coatings on dual phase steel

    International Nuclear Information System (INIS)

    Song, G.M.; Vystavel, T.; Pers, N. van der; De Hosson, J.Th.M.; Sloof, W.G.

    2012-01-01

    Highlights: ► Amorphous manganese oxides present at the steel surface impair the adhesion of the zinc coating. ► The adhesion of the various interfaces that exist in zinc coated steel is quantitatively estimated using the “Macroscopic Atom” model. ► Zinc coating delaminates along the zinc layer/inhibition layer and ζ-FeZn 13 particle/inhibition layer interfaces, which agrees the theoretical calculation. - Abstract: The microstructure of hot dip galvanized zinc coatings on dual phase steel was investigated by electron microscopy and the coating adhesion characterized by tensile testing. The zinc coating consists of a zinc layer and columnar ζ-FeZn 13 particles on top of a thin inhibition layer adjacent to the steel substrate. The inhibition layer is a thin compact and continuous layer that consists of η-Fe 2 Al 5–x Zn x fine and coarse particles. The coarse faceted particles are on top and fine faceted particles are at the bottom. The steel surface is covered with small fraction manganese oxides, which may impair adhesion of the zinc coating. The adhesion at various interfaces that exist in zinc-coated steel was quantitatively estimated using a so-called “macroscopic atom” model. In addition, the adhesion at the interfaces in zinc-coated steel was qualitatively assessed by examining the fracture and delamination behavior upon tensile testing. In accordance with this model, fracture along zinc grain boundaries preceded fracture along the zinc layer/inhibition layer and ζ-FeZn 13 particle/inhibition layer interfaces.

  15. On the Processing of Martensitic Steels in Continuous Galvanizing Lines: Part II

    Science.gov (United States)

    Song, Taejin; Kwak, Jaihyun; de Cooman, B. C.

    2012-01-01

    The conventional continuous hot-dip galvanizing (GI) and galvannealing (GA) processes can be applied to untransformed austenite to produce Zn and Zn-alloy coated low-carbon ultra-high-strength martensitic steel provided specific alloying additions are made. The most suitable austenite decomposition behavior results from the combined addition of boron, Cr, and Mo, which results in a pronounced transformation bay during isothermal transformation. The occurrence of this transformation bay implies a considerable retardation of the austenite decomposition in the temperature range below the bay, which is close to the stages in the continuous galvanizing line (CGL) thermal cycle related to the GI and GA processes. After the GI and GA processes, a small amount of granular bainite, which consists of bainitic ferrite and discrete islands of martensite/austenite (M/A) constituents embedded in martensite matrix, is present in the microstructure. The ultimate tensile strength (UTS) of the steel after the GI and GA cycle was over 1300 MPa, and the stress-strain curve was continuous without any yielding phenomena.

  16. Relationship between surface structure of silicon containing steel and adhesion of hot dip galvanized coating; Si gan'yu koban no hyomen kozo to yoyu aen mekki micchakuseino kankei

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, Y.; Hashimoto, S.; Ishibashi, Y. [Kokan Keisoku K.K., Kawasaki (Japan); Inagaki, J. [NKK Corp., Tokyo (Japan); Fukuda, Y. [Shuibuoka University, Shizuoka (Japan)

    2000-06-01

    The surface of the annealed steel and the exfoliated interface of the coating for the hot dip galvanized Si containing steel sheets was characterized by using SEM (Scanning Electron Microscope), AES (Auger Electron Spectroscopy) and TEM (Transmission Electron Microscopy). The adhesion of the coatings have depended on the Si content of the steel. It have been found that MnSiO{sub 3} particles are formed at the surface of the annealed steels having high Si content and that two types of grain having different distribution of the oxide exist in the steels. Large oxide particles have been formed in one type of grain and small particles are formed in the other type of grain. The different type of Fe-Zn alloy are formed on two types of grains. It have been observed that the oxide particles exist at the interface of exfoliated coatings after the adhesion test for the steels with high Si content. The distribution of the oxide particles observed at the bottom of the exfoliated coating is quite similar to that of the surface oxide of the annealed steel. From these results, the exfoliation of the coating has initiated at the oxide particles of the steel surface that has been not reduced during the hot dip galvanizing. (author)

  17. On the Processing of Martensitic Steels in Continuous Galvanizing Lines: Part 1

    Science.gov (United States)

    Song, Taejin; Kwak, Jaihyun; de Cooman, B. C.

    2012-01-01

    Whereas low-carbon (galvanizing lines make it difficult to produce hot-dip Zn or Zn-alloy coated high-strength martensitic grades. This is because of the tempering processes occurring during dipping of the strip in the liquid Zn bath and, in the case of galvannealed sheet steel, the short thermal treatment required to achieve the alloying between the Zn and the steel. These short additional thermal treatments last less than 30 seconds but severely degrade the mechanical properties. Using a combination of internal friction, X-ray diffraction, and transmission electron microscopy, it is shown that the ultrafine-grained lath microstructure allows for a rapid dislocation recovery and carbide formation during the galvanizing processes. In addition, the effective dislocation pinning occurring during the galvannealing process results in strain localization and the suppression of strain hardening.

  18. Role of Al in Zn bath on the formation of the inhibition layer during hot-dip galvanizing for a 1.2Si-1.5Mn transformation-induced plasticity steel

    Science.gov (United States)

    Wang, Kuang-Kuo; Hsu, Chiung-Wen; Chang, Liuwen; Gan, Dershin; Yang, Kuo-Cheng

    2013-11-01

    This study investigated the interaction between the Al in the Zn bath and the surface oxides formed by selective oxidation on a 1.2Si-1.5Mn TRIP steel during hot-dip galvanizing. XPS and TEM were employed for characterization. The results indicated that the amorphous xMnO·SiO2 oxide could react with Al to form a Si-Mn-Al-containing oxide. The crystalline MnSiO3 and Mn2SiO4 oxides could be largely reduced by Al to form holes in the oxide film. Consequently, the steel covered by a layer of mixed xMnO·SiO2 and MnSiO3 could form a continuous Fe2Al5 inhibition layer and showed the highest galvanizability among the three samples examined.

  19. Influence of Gas Atmosphere Dew Point on the Selective Oxidation and the Reactive Wetting During Hot Dip Galvanizing of CMnSi TRIP Steel

    Science.gov (United States)

    Cho, Lawrence; Lee, Seok Jae; Kim, Myung Soo; Kim, Young Ha; De Cooman, Bruno C.

    2013-01-01

    The selective oxidation and reactive wetting of intercritically annealed Si-bearing CMnSi transformation-induced plasticity steels were investigated by high-resolution transmission electron microscopy. In a N2 + 10 pct H2 gas atmosphere with a dew point (DP) ranging from 213 K to 278 K (-60 °C to 5 °C), a continuous layer of selective oxides was formed on the surface. Annealing in a higher DP gas atmosphere resulted in a thinner layer of external oxidation and a greater depth of internal oxidation. The hot dipping was carried out in a Zn bath containing 0.22 mass pct Al, and the bath temperature was 733 K (460 °C). Coarse and discontinuous Fe2Al5- x Zn x grains and Fe-Zn intermetallics (ζ and δ) were observed at the steel/coating interface after the hot dip galvanizing (HDG) of panels were annealed in a low DP atmosphere 213 K (-60 °C). The Fe-Zn intermetallics were formed both in areas where the Fe2Al5- x Zn x inhibition layer had not been formed and on top of non-stoichiometric Fe-Al-Zn crystals. Poor wetting was observed on panels annealed in a low DP atmosphere because of the formation of thick film-type oxides on the surface. After annealing in higher DP gas atmospheres, i.e., 263 K and 278 K (-10 °C and 5 °C), a continuous and fine-grained Fe2Al5- x Zn x layer was formed. No Fe-Zn intermetallics were formed. The small grain size of the inhibition layer was attributed to the nucleation of the Fe2Al5- x Zn x grains on small ferrite sub-surface grains and the presence of granular surface oxides. A high DP atmosphere can therefore significantly contribute to the decrease of Zn-coating defects on CMnSi TRIP steels processed in HDG lines.

  20. Heat treatment, microstructure and mechanical properties of a C–Mn–Al–P hot dip galvanizing TRIP steel

    International Nuclear Information System (INIS)

    Ding, Wei; Hedström, Peter; Li, Yan

    2016-01-01

    Heat treatments of a hot dip galvanizing TRIP (Transformation induced plasticity) steel with chemical composition 0.20C-1.50Mn-1.2Al-0.07P(mass%) were performed in a Gleeble 3500 laboratory equipment. The heat treatment process parameters were varied to investigate the effect of intercritical annealing temperature as well as isothermal bainitic transformation (IBT) temperature and time, on the microstructure and the mechanical properties. The microstructure was investigated using scanning electron microscopy, transmission electron microscopy and x-ray diffraction, while mechanical properties were evaluated by tensile testing. Furthermore, to generate a better understanding of the phase transformations during heat treatment, dilatometry trials were conducted. The desired microstructure containing ferrite, bainite, retained austenite and martensite was obtained after the heat treatments. It was further found that the IBT is critical in determining the mechanical properties of the steel, since it controls the fraction of bainite. With increasing bainite fraction, the fraction of retained austenite increases while the fraction of martensite decreases. The mechanical properties of the steel are excellent with a tensile strength above 780 MPa (expect in one case) and elongation above 22%.

  1. Heat treatment, microstructure and mechanical properties of a C–Mn–Al–P hot dip galvanizing TRIP steel

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Wei [School of Material and Metallurgy, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Department of Materials Science and Engineering, KTH Royal Institute of Technology, SE-100 44 Stockholm (Sweden); Bayan Obo multimetallic resource comprehensive utilization Key lab, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Hedström, Peter [Department of Materials Science and Engineering, KTH Royal Institute of Technology, SE-100 44 Stockholm (Sweden); Li, Yan [Department of Materials Science and Engineering, KTH Royal Institute of Technology, SE-100 44 Stockholm (Sweden); Bayan Obo multimetallic resource comprehensive utilization Key lab, Inner Mongolia University of Science and Technology, Baotou 014010 (China)

    2016-09-30

    Heat treatments of a hot dip galvanizing TRIP (Transformation induced plasticity) steel with chemical composition 0.20C-1.50Mn-1.2Al-0.07P(mass%) were performed in a Gleeble 3500 laboratory equipment. The heat treatment process parameters were varied to investigate the effect of intercritical annealing temperature as well as isothermal bainitic transformation (IBT) temperature and time, on the microstructure and the mechanical properties. The microstructure was investigated using scanning electron microscopy, transmission electron microscopy and x-ray diffraction, while mechanical properties were evaluated by tensile testing. Furthermore, to generate a better understanding of the phase transformations during heat treatment, dilatometry trials were conducted. The desired microstructure containing ferrite, bainite, retained austenite and martensite was obtained after the heat treatments. It was further found that the IBT is critical in determining the mechanical properties of the steel, since it controls the fraction of bainite. With increasing bainite fraction, the fraction of retained austenite increases while the fraction of martensite decreases. The mechanical properties of the steel are excellent with a tensile strength above 780 MPa (expect in one case) and elongation above 22%.

  2. Application of Bayesian Networks to Diagnostics of Hot Dip Galvanized Coasts

    Directory of Open Access Journals (Sweden)

    A. Adrian

    2007-07-01

    Full Text Available This study presents an output of the application of a probabilistic method of inference based on Bayes' rule in the diagnosis of defects formed during hot-dip galvanising process of casting products. Bayesian cause-effect network for given group of surface defects and its causes was build. Many factors causing defects was taken into consideration like: technological parameters, technological nodes and character of cause. The advantages and drawbacks of a probabilistic method of representation of the incomplete and uncertain empirical knowledge were highlighted.

  3. Comparative life cycle cost assessment of painted and hot-dip galvanized bridges.

    Science.gov (United States)

    Rossi, B; Marquart, S; Rossi, G

    2017-07-15

    The study addresses the life cycle cost assessment (LCCA) of steel bridges, focusing on the maintenance activities and the maintenance scenario. Firstly, the unit costs of maintenance activities and their durability (i.e. the time between two activities) are evaluated. Pragmatic data are provided for the environment category C4 and for three activities: Patch Up, Overcoating and Remove & Replace. A comparative LCCA for a typical hypothetic steel girder bridge is carried out, either painted or hot-dip galvanized (HDG), in the environmental class C4. The LCC versus the cumulated life is provided for both options. The initial cost of the steel unpainted option is only 50.3% of the HDG option. It is shown that after 'Overcoating' occurring at 18.5 years, the total Net Present Value (NPV) of the painted option surpasses that of the HDG option. A sensitivity analysis of the NPV to the cost and service life parameters, the escalation and discount rates is then performed. The discount and escalation rates, considerably influences the total LCC, following a non-linear trend. The total LCC decreases with the discount rate increasing and, conversely, increases with the escalation rate increasing. Secondly, the influence of the maintenance scenario on the total LCC is assessed based on a probabilistic approach. A permutation of the three independent maintenance activities assumed to occur six times over the life of the bridge is considered and a probability of occurrence is associated to each unique scenario. The most probable scenarios are then classified according to their NPV or achieved service life. This approach leads to the definition of a cost-effective maintenance scenario i.e. the scenario, within all the considered permutations, that has the minimum LCC in a range of lifespan. Besides, the probabilistic analysis also shows that, whatever the scenario, the return on investment period ranges between 18.5 years and 24.2 years. After that period, the HDG option becomes

  4. Simulation to coating weight control for galvanizing

    Science.gov (United States)

    Wang, Junsheng; Yan, Zhang; Wu, Kunkui; Song, Lei

    2013-05-01

    Zinc coating weight control is one of the most critical issues for continuous galvanizing line. The process has the characteristic of variable-time large time delay, nonlinear, multivariable. It can result in seriously coating weight error and non-uniform coating. We develop a control system, which can automatically control the air knives pressure and its position to give a constant and uniform zinc coating, in accordance with customer-order specification through an auto-adaptive empirical model-based feed forward adaptive controller, and two model-free adaptive feedback controllers . The proposed models with controller were applied to continuous galvanizing line (CGL) at Angang Steel Works. By the production results, the precise and stability of the control model reduces over-coating weight and improves coating uniform. The product for this hot dip galvanizing line does not only satisfy the customers' quality requirement but also save the zinc consumption.

  5. A novel method of utilization of hot dip galvanizing slag using the heat waste from itself for protection from radiation.

    Science.gov (United States)

    Dong, Mengge; Xue, Xiangxin; Kumar, Ashok; Yang, He; Sayyed, M I; Liu, Shan; Bu, Erjun

    2018-02-15

    A novel, unconventional, low cost, eco-friendly and effective shielding materials have been made utilizing the hot dip galvanizing slag using the heat waste from itself, thereby saving the natural resources and preventing the environmental pollution. SEM-EDS of shielding materials indicates that the other elements are distributed in Zn element. The mass attenuation properties of shielding materials were measured using a narrow beam geometrical setup at 0.662MeV, 1.17MeV and 1.33MeV. The half value thickness layer, effective atomic number, and electron density were used to analyze the shielding performance of the materials. The EBFs and EABFs for the prepared shielding materials were also studied with incident photon energy for penetration depths upto 40mfp. The shielding effectiveness has been compared with lead, iron, zinc, some standard shielding concretes, different glasses and some alloys. The shielding effectiveness of the prepared samples is almost found comparable to iron, zinc, selected alloys and glasses while better than some standard shielding concretes. In addition, it is also found that the bending strength of all shielding materials is more than 110MPa. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Examination of the Mg-Zn phase formation in hot-dip galvanized steel sheet; Untersuchung der Mg-Zn-Phasenbildung in feuerverzinktem Stahlblech

    Energy Technology Data Exchange (ETDEWEB)

    Zywitzki, Olaf; Modes, Thomas; Scheffel, Bert; Metzner, Christoph [Fraunhofer-Institut fuer Elektronenstrahl- und Plasmatechnik, Dresden (Germany)

    2012-07-01

    Zinc-magnesium layers have been produced by a combination of conventional hot-dip galvanizing and PVD magnesium coating. A subsequent short heat treatment causes the diffusion of magnesium into the zinc layer. The influence of the maximum temperature of the heat treatment on the diffusion of magnesium and on the type and distribution of the formed intermetallic Mg-Zn phases has been examined in detail in a temperature range from 300 to 400 C by means of X-ray phase analyses and metallographic cross sections. With increasing temperature a sequential intermetallic Mg-Zn phase formation has been detected. At 300 C, an initial magnesium rich, intermetallic MgZn{sub 2} surface layer is formed, which, at higher temperatures from 335 to 379 C, is progressively transformed into a zinc rich Mg{sub 2}Zn{sub 11} layer by interdiffusion. In this context, the nucleation of the Mg{sub 2}Zn{sub 11} phase takes place on the interface between the MgZn{sub 2} and the Zn phase. Above the peritectic temperature of 381 C, the microstructure is composed of a zinc matrix in which precipitated MgZn{sub 2} is dispersed. (orig.)

  7. Coating adherence in galvanized steel assessed by acoustic emission wavelet analysis

    International Nuclear Information System (INIS)

    Gallego, Antolino; Gil, Jose F.; Vico, Juan M.; Ruzzante, Jose E.; Piotrkowski, Rosa

    2005-01-01

    Coating-substrate adherence in galvanized steel is evaluated by acoustic emission wavelet analysis in scratch tests on hot-dip galvanized samples. The acoustic emission results are compared with optical and electron microscopy observations in order to understand coating features related to adherence and to establish criteria aimed at improving the manufacture process

  8. Overall model of the dynamic behaviour of the steel strip in an annealing heating furnace on a hot-dip galvanizing line

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-de-Pison, F.J.; Pernia, A.; Jimenez-Macias, E.; Fernandez, R.

    2010-07-01

    Predicting the temperature of the steel strip in the annealing process in a hot-dip galvanizing line (HDGL) is important to ensure the physical properties of the processed material. The development of an accurate model that is capable of predicting the temperature the strip will reach according to the furnaces variations in temperature and speed, its dimensions and the steels chemical properties, is a requirement that is being increasingly called for by industrial plants of this nature. This paper presents a comparative study made between several types of algorithms of Data Mining and Artificial Intelligence for the design of an efficient and overall prediction model that will allow determining the strips variation in temperature according to the physico-chemical specifications of the coils to be processed, and fluctuations in temperature and speed that are recorded within the annealing process. The ultimate goal is to find a model that is effectively applicable to coils of new types of steel or sizes that are being processed for the first time. This model renders it possible to fine-tune the control model in order to standardise the treatment in areas of the strip in which there is a transition between coils of different sizes or types of steel. (Author).

  9. Studies into the Factors that Affects the Service Integrity of Galvanizing Kettle

    OpenAIRE

    Muhammed Olawale Hakeem AMUDA; Ayisat Adebukunola LAWAL; Olakunle Wasiu SUBAIR; Ganiyu Ishola LAWAL

    2008-01-01

    The finding of studies into the factors that affects optimal performance of galvanizing kettle is presented in this paper. The production schedule and history of a failed galvanizing kettle for 3-consecutively years in a hot-dip galvanizing industry was collated and analyzed. The analysis of the collated data revealed that average galvanizing temperatures for the 3-year under review were 483.9°C (2003), 482.25°C (2004) and 482°C (2005) respectively. The amount of flux, and dross produced in t...

  10. Studies into the Factors that Affects the Service Integrity of Galvanizing Kettle

    Directory of Open Access Journals (Sweden)

    Muhammed Olawale Hakeem AMUDA

    2008-12-01

    Full Text Available The finding of studies into the factors that affects optimal performance of galvanizing kettle is presented in this paper. The production schedule and history of a failed galvanizing kettle for 3-consecutively years in a hot-dip galvanizing industry was collated and analyzed. The analysis of the collated data revealed that average galvanizing temperatures for the 3-year under review were 483.9°C (2003, 482.25°C (2004 and 482°C (2005 respectively. The amount of flux, and dross produced in the corresponding years were 169.15kg and 31.6 tons, 56.31kg and 10.5 tons and 101.14 and 18.91 tonnes for 2003, 2004 and 2005 respectively. During these years, zinc consumed averaged 647, 334 and 446 tonnes respectively.Stochiometry evaluation of flux, and dross in a hot-dip galvanizing process determined flux required as 60 kg/year and dross produced as 90 slabs / month.The study revealed that the lifespan of galvanizing kettle is greatly reduced by temperature fluctuation, dross formation, excess flux additions and combinations of these factors.It is recommended that improved service integrity of galvanizing kettle is assured at galvanizing temperature of 460°C, flux consumption of 0.15 –0.20kg daily and constant removal of dross at 3-5 slabs per day. This reduces the formation of skim lines, which leads to pits on the walls of the kettle.

  11. Life Improvement of Pot Hardware in Continuous Hot Dipping Processes Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Xingbo Liu

    2006-01-18

    The process of continuous galvanizing of rolled sheet steel includes immersion into a bath of molten zinc/aluminum alloy. The steel strip is dipped in the molten bath through a series of driving motors and rollers which control the speed and tension of the strip, with the ability to modify both the amount of coating applied to the steel as well as the thickness and width of the sheet being galvanized. There are three rolls used to guide the steel strip through the molten metal bath. The rolls that operate in the molten Zn/Al are subject to a severely corrosive environment and require frequent changing. The performance of this equipment, the metallic hardware submerged in the molten Zn/Al bath, is the focus of this research. The primary objective of this research is to extend the performance life of the metallic hardware components of molten Zn/Al pot hardware by an order of magnitude. Typical galvanizing operations experience downtimes on the order of every two weeks to change the metallic hardware submerged in the molten metal bath. This is an expensive process for industry which takes upwards of 3 days for a complete turn around to resume normal operation. Each roll bridle consists of a sink, stabilizer, and corrector roll with accompanying bearing components. The cost of the bridle rig with all components is as much as $25,000 dollars just for materials. These inefficiencies are of concern to the steel coating companies and serve as a potential market for many materials suppliers. This research effort served as a bridge between the market potential and industry need to provide an objective analytical and mechanistic approach to the problem of wear and corrosion of molten metal bath hardware in a continuous sheet galvanizing line. The approach of the investigators was to provide a means of testing and analysis that was both expeditious and cost effective. The consortium of researchers from West Virginia University and Oak Ridge National Laboratory developed

  12. Formation of Outburst Structure in Hot Dip Galvannealed Coatings on IF Steels

    Directory of Open Access Journals (Sweden)

    Kollárová, M.

    2007-01-01

    Full Text Available Outburst structure in two industrially produced hot dip galvanized interstitial free steel sheets for automotive industry after additional annealing has been examined. Ti IF steel was found to form weak outburst structure in the early stage of annealing, followed by frontal growth of Fe-Zn phases during further heating. The high reactivity of this steel was confirmed by rapid G-phase formation. Under the same conditions, Ti-Nb-P IF steel exhibited frontal growth of Fe-Zn compounds without G-phase formation due to relatively high phosphorous content, which is known as inhibitor of Fe-Zn reaction, but simultaneously significant occurrence of undesired outburst structures was recorded. It was assumed that the phosphorous content was insufficient and/or ferrite grain was very fine.

  13. Corrosion Mechanism and Bond-Strength Study on Galvanized Steel in Concrete Environment

    Energy Technology Data Exchange (ETDEWEB)

    Kouril, M.; Pokorny, P.; Stoulil, J. [University of Chemistry and Technology, Prague (Czech Republic)

    2017-04-15

    Zinc coating on carbon steels give the higher corrosion resistance in chloride containing environments and in carbonated concrete. However, hydrogen evolution accompanies the corrosion of zinc in the initial activity in fresh concrete, which can lead to the formation of a porous structure at the reinforcement -concrete interface, which can potentially reduce the bond-strength of the reinforcement with concrete. The present study examines the mechanism of the corrosion of hot-dip galvanized steel in detail, as in the model pore solutions and real concrete. Calcium ion plays an important role in the corrosion mechanism, as it prevents the formation of passive layers on zinc at an elevated alkalinity. The corrosion rate of galvanized steel decreases in accordance with the exposure time; however, the reason for this is not the zinc transition into passivity, but the consumption of the less corrosion-resistant phases of hot-dip galvanizing in the concrete environment. The results on the electrochemical tests have been confirmed by the bond-strength test for the reinforcement of concrete and by evaluating the porosity of the cement adjacent to the reinforcement.

  14. Galvanic coupling effects for module-mounting elements of ground-mounted photovoltaic power station

    Directory of Open Access Journals (Sweden)

    Pierozynski Boguslaw

    2017-12-01

    Full Text Available This communication reports on the concerns associated with possible generation of galvanic coupling effects for construction materials that are used to manufacture mounting assemblies for ground-mounted photovoltaic (PV power stations. For this purpose, six macro-corrosion galvanic cells were assembled, including: hot-dip Zn/Magnelis®-coated steel/Al and stainless steel (SS/Al cells. Corrosion experiments involved continuous, ca. three-month exposure of these couplings in 3 wt.% NaCl solution, conducted at room temperature for a stable pH value of around 8. All corrosion cells were subjected to regular assessment of galvanic current-density and potential parameters, where special consideration was given to compare the corrosion behaviour of Zn-coated steel samples with that of Magnelis®-coated electrodes. Characterization of surface condition and elemental composition for examined materials was carried-out by means of SEM and EDX spectroscopy techniques.

  15. Reaction kinetics of the formation of intermetallic Fe – Zn during hot - dip galvanizing of steel

    Directory of Open Access Journals (Sweden)

    P. Pokorny

    2016-01-01

    Full Text Available This review article mainly describes the composition of intermetallic Fe - Zn, i.e. zeta (ζ, delta (δ1k + δ1p, gamma1 (Γ1 and gamma (Γ on galvanized steel during low temperature galvanization (t ~ 450 °C. It gives detailed the formation, growth of individual phases during galvanization and their interaction. In terms of the kinetics, the formation of the coating is defined by a parabolic kinetic equation of the growth of different intermetallic phases under ideal conditions. From the available literature the rate constants of the formation of individual intermetallic phases and also for the total coating are cited. The composition of the intermetallic phases, iron content, crystal structure, and group symmetry in which the surface of galvanized steel forms.

  16. Galvanizing and Galvannealing Behavior of CMnSiCr Dual-Phase Steels

    Science.gov (United States)

    Lin, Ko-Chun; Chu, Peng-Wei; Lin, Chao-Sung; Chen, Hon-Bor

    2013-06-01

    Alloying elements, such as Mn, Mo, Si, and Cr, are commonly used to enhance the strength of advanced high-strength steels. Those elements also play an important role in the hot-dip galvanizing (GI) and galvannealing (GA) process. In this study, two kinds of CMnSiCr dual-phase steels were galvanized and galvannealed using a hot-dip simulator to investigate the effect of the alloying elements on the microstructure of the GI and GA coatings. The results showed that the dual-phase steels had good galvanizability because no bare spots were observed and the Fe-Zn phases were readily formed at the interface. However, the alloying reaction during the GA process was significantly hindered. XPS analysis showed that external oxidation occurred under an extremely low dew point [213 K to 203 K (-60 °C to -70 °C)] atmosphere during the annealing prior to hot dipping. However, most of the oxides were reduced during the GI process. After the GI process, the Al was present as solid solutes in the Fe-Zn phase, suggesting that the Fe-Zn phase was formed from the transformation of the Fe-Al inhibition alloy. Meanwhile, the solubility of Si in the ζ phase was extremely low. With continued GA reaction, the ζ phase transformed into the δ phase, which contained approximately 1.0 at.pct Si. The Si also diffused into the Zn layer during the GA reaction. Hence, the ζ phase did not homogeneously nucleate at the steel substrate/Zn coating interface, but was found at the area away from the interface. Therefore, the Fe-Zn phases on the CMnSiCr dual-phase steels were relatively non-uniform compared to those on interstitial-free steel.

  17. Adhesion of Zinc Hot-dip Coatings

    Directory of Open Access Journals (Sweden)

    Michal Černý

    2014-01-01

    Full Text Available The work is focused on verification of quality adhesion of zinc coating. It describes elements which affect quality and adhesive solidity within the coating. For assessment itself it will be neccessary to get know the basic elements which can affect adhesion of hot-dip coating which will be essential for choosing suitable samples for verification itself. These elements characterise acoustic responses during delamination coating. They affect elements influencing progress of signal. In research there is also a summary of existing methods for testing adhesion of coatings. As a result a new proposal of a new method comes out for purpose of quality testing of adhesion zinc hot-dip coating. The results of verification of this method are put to scientific analysis and findings lead to assessment of proposed method and its application in technical practise.The goal of this contribution is also include to proposed methodology testing adhesion zinc coating by nondestructive diagnostic method of acoustic emission (AE, which would monitor characterise progress of coating delamination of hot-dip zinc from basic material in way to adhesion tests would be practicable in situ. It can be enabled by analysis and assessment of results acquired by method AE and its application within verification of new method of adhesion anti-corrosive zinc coating.

  18. Theoretical Investigation of the Interfacial Reactions during Hot-Dip Galvanizing of Steel

    Science.gov (United States)

    Mandal, G. K.; Balasubramaniam, R.; Mehrotra, S. P.

    2009-03-01

    In the modern galvanizing line, as soon as the steel strip enters the aluminum-containing zinc bath, two reactions occur at the strip and the liquid-zinc alloy interface: (1) iron rapidly dissolves from the strip surface, raising the iron concentration in the liquid phase at the strip-liquid interface; and (2) aluminum forms a stable aluminum-iron intermetallic compound layer at the strip-coating interface due to its greater affinity toward iron. The main objective of this study is to develop a simple and realistic mathematical model for better understanding of the kinetics of galvanizing reactions at the strip and the liquid-zinc alloy interface. In the present study, a model is proposed to simulate the effect of various process parameters on iron dissolution in the bath, as well as, aluminum-rich inhibition layer formation at the substrate-coating interface. The transient-temperature profile of the immersed strip is predicted based on conductive and convective heat-transfer mechanisms. The inhibition-layer thickness at the substrate-coating interface is predicted by assuming the cooling path of the immersed strip consists of a series of isothermal holds of infinitesimal time-step. The influence of galvanizing reaction is assessed by considering nucleation and growth mechanisms at each hold time, which is used to estimate the total effect of the immersion time on the formation mechanism of the inhibition layer. The iron- dissolution model is developed based on well established principles of diffusion taking into consideration the area fraction covered by the intermetallic on the strip surface during formation of the inhibition layer. The model can be effectively used to monitor the dross formation in the bath by optimizing the process parameters. Theoretical predictions are compared with the findings of other researchers. Simulated results are in good agreement with the theoretical and experimental observation carried out by other investigators.

  19. Investigation of shinning Spot Defect on Hot-Dip Galvanized Steel Sheets

    International Nuclear Information System (INIS)

    Yonggang, Liu; Lei, Cui

    2014-01-01

    Shinning spot defects on galvanized steel sheets were studied by optical microscope, scanning electron microscope(SEM), Energy Dispersive Spectrometer (EDS) and Laser-Induced Breakdown Spectroscopy Original Position Statistic Distribution Analysis (LIBSOPA) in this study. The research shows that the coating thickness of shinning spot defects which caused by the substrate defect is much lower than normal area, and when skin passed, the shinning spot defect area can not touch with skin pass roll which result in the surface of shinning spot is flat while normal area is rough. The different coating morphologies have different effects on the reflection of light, which cause the shinning spot defects more brighter than normal area

  20. Study on the wiping gas jet in continuous galvanizing line

    Science.gov (United States)

    Kweon, Yong-Hun; Kim, Heuy-Dong

    2011-09-01

    In the continuous hot-dip galvanizing process, the gas-jet wiping is used to control the coating thickness of moving steel strip. The high speed gas-jet discharged from the nozzle slot impinges on the strip, and at this moment, wipes the liquid coating layer dragged by a moving strip. The coating thickness is generally influenced on the flow characteristics of wiping gas-jet such as the impinging pressure distribution, pressure gradient and shear stress distribution on the surface of strip. The flow characteristics of wiping gas-jet mentioned above depends upon considerably both the process operating conditions such as the nozzle pressure, nozzle-to-strip distance and line speed, and the geometry of gas-jet wiping apparatus such as the height of nozzle slot. In the present study, the effect of the geometry of nozzle on the coating thickness is investigated with the help of a computational fluid dynamics method. The height of nozzle slot is varied in the range of 0.6mm to 1.7mm. A finite volume method (FVM) is employed to solve two-dimensional, steady, compressible Navier-Stokes equations. Based upon the results obtained, the effect of the height of nozzle slot in the gas-jet wiping process is discussed in detail. The computational results show that for a given standoff distance between the nozzle to the strip, the effective height of nozzle slot exists in achieving thinner coating thickness.

  1. Hot-Dip Coating of Lead-free Aluminum on Steel Substrates with Ultrasonic Vibration

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Hot-dip coating has been practically employed in manufacturing zinc alloy coated steel sheets. However, it is difficult to coat aluminum alloy on a bulky steel substrate without sufficient preheating, because a rapidly solidified layer containing gas babbles is formed on a substrate surface. A variety of iron-aluminides are also formed at the interface of a steel and aluminum hot-dip coating system, which is the main difficulty in joining of steel with aluminum. Ultrasonic vibration was applied to a steel substrate during hot-dip coating of aluminum alloy to control a rapidly solidified layer and a brittle reaction layer. Hot dipping of columnar steel substrates into molten aluminum alloy (Al-2.7 mass fraction Si-4.6 mass fraction Sn) was carried out through the use of a Langevin oscillator with resonant frequency of 19.5 kHz. The application of ultrasonic vibration is quite effective to control a rapidly solidified layer and a surface oxide layer from a substrate surface by the sonocapillary effect based on a cavitation phenomenon, so that the intimate contact is achieved at the beginning of hot-dip coating. The application of ultrasonic vibration to hot-dipping is effective to control a reaction layer with less than 5μm in thickness. An impact test exhibits that the good adhesive strength is approved in hot-dipped aluminum coatings with a thin reaction layer of approximately 5μm.

  2. CO2 laser welding of galvanized steel sheets using vent holes

    International Nuclear Information System (INIS)

    Chen Weichiat; Ackerson, Paul; Molian, Pal

    2009-01-01

    Joining of galvanized steels is a challenging issue in the automotive industry because of the vaporization of zinc at 906 deg. C during fusion welding of steel (>1530 deg. C). In this work, hot-dip galvanized steel sheets of 0.68 mm thick (24-gage) were pre-drilled using a pulsed Nd:YAG laser to form vent holes along the weld line and then seam welded in the lap-joint configuration using a continuous wave CO 2 laser. The welds were evaluated through optical and scanning electron microscopy and tensile/hardness tests. The vent holes allowed zinc vapors to escape through the weld zone without causing expulsion of molten metal, thereby eliminating the defects such as porosity, spatter, and loss of penetration. In addition, riveting of welds occurred so long as the weld width was greater than the hole diameter that in turn provided much higher strength over the traditional 'joint gap' method

  3. Analysis of the corrosion products on galvanized steels by FTIR spectroscopy

    International Nuclear Information System (INIS)

    Kasperek, J.

    1998-01-01

    FTIR reflectance spectroscopy has been used for the characterization of products formed by an accelerated wet ageing test on industrial hot-dip galvanized steel. Several aluminium contents are selected. Various products have been detected in this study. The kind and amount vary with the substrate, the type of ageing test used, the relative humidity level and the temperature. The galvanized coatings studied show a mixed zinc-aluminium compound, Zn 6 Al 2 (OH) 16 CO 3 .4H 2O. This phase is observed from the first exposure time on all coatings regardless of the amount of aluminium. Contrary to zinc, no basic aluminium compound has been detected. (orig.)

  4. Effect of Process Variables on the Grain Size and Crystallographic Texture of Hot-Dip Galvanized Coatings

    Science.gov (United States)

    Kaboli, Shirin; McDermid, Joseph R.

    2014-08-01

    A galvanizing simulator was used to determine the effect of galvanizing bath antimony (Sb) content, substrate surface roughness, and cooling rate on the microstructural development of metallic zinc coatings. Substrate surface roughness was varied through the use of relatively rough hot-rolled and relatively smooth bright-rolled steels, cooling rates were varied from 0.1 to 10 K/s, and bulk bath Sb levels were varied from 0 to 0.1 wt pct. In general, it was found that increasing bath Sb content resulted in coatings with a larger grain size and strongly promoted the development of coatings with the close-packed {0002} basal plane parallel to the substrate surface. Increasing substrate surface roughness tended to decrease the coating grain size and promoted a more random coating crystallographic texture, except in the case of the highest Sb content bath (0.1 wt pct Sb), where substrate roughness had no significant effect on grain size except at higher cooling rates (10 K/s). Increased cooling rates tended to decrease the coating grain size and promote the {0002} basal orientation. Calculations showed that increasing the bath Sb content from 0 to 0.1 wt pct Sb increased the dendrite tip growth velocity from 0.06 to 0.11 cm/s by decreasing the solid-liquid interface surface energy from 0.77 to 0.45 J/m2. Increased dendrite tip velocity only partially explains the formation of larger zinc grains at higher Sb levels. It was also found that the classic nucleation theory cannot completely explain the present experimental observations, particularly the effect of increasing the bath Sb, where the classical theory predicts increased nucleation and a finer grain size. In this case, the "poisoning" theory of nucleation sites by segregated Sb may provide a partial explanation. However, any analysis is greatly hampered by the lack of fundamental thermodynamic information such as partition coefficients and surface energies and by a lack of fundamental structural studies. Overall

  5. Effect of Process Parameters on the Structure and Properties of Galvanized Sheets

    Science.gov (United States)

    Shukla, S. K.; Saha, B. B.; Triathi, B. D.; Avtar, Ram

    2010-07-01

    The effect of galvanizing parameters on the structure (spangle size and coating microstructure) and properties (formability and corrosion resistance) of galvanized sheets was studied in a hot dip process simulator (HDPS) in a conventional Pb bearing (0.08-0.10%) zinc bath by varying zinc bath Al level (0.10-0.28%), bath temperature (718-743 K), dipping time (1.5-3.5 s), wiping gas flow rate (200-450 lpm), nozzle distance (15-17 mm) and wiping delay time (0.1-2.1 s). Al level in the range of 0.18-0.24% in combination with dipping time of 1.5-2.5 s and bath temperature of 718-733 K results in superior formability ( E cv: ~9.3 mm) of the composite (thickness: 0.8 mm). High post-dip cooling rates (~25 K/s) suppress spangle growth (spangle size: ~2 mm). The spangle size of the GI sheet strongly influences the corrosion rate which increases from 5.8 to 9.2 mpy with a decrease in spangle size from 17.5 to 3 mm. By controlling the Al level (0.20%) in zinc bath and bath temperature (733 K), the corrosion rate of mini-spangle GI sheet can be controlled to a level of 5.5 mpy.

  6. THE METHOD OF ROLL SURFACE QUALITY MEASUREMENT FOR CONTINUOUS HOT DIP ZINC COATED STEEL SHEET PRODUCTION LINE

    Directory of Open Access Journals (Sweden)

    Ki Yong Choi

    2015-01-01

    Full Text Available The present paper describes a developed analyzing system of roll surface during the process of continuous hot dip zinc coated steel sheet production line, in particular, adhering problem by transferred inclusions from roll to steel sheet surface during annealing process so called the pickup. The simulated test machine for coated roll surface in processing line has been designed and performed. The system makes it possible to analyze roll surface condition according to pickup phenomena from various roll coatings concerning operating conditions of hearth rolls in annealing furnace. The algorithm of fast pickup detection on surface is developed on the base of processing of several optical images of surface. The parameters for quality estimation of surface with pickups were developed. The optical system for images registration and image processing electronics may be used in real time and embed in processing line.

  7. Si、Mg、RE对热浸镀锌铝基合金镀层组织与性能的影响研究进展%Effects of Si, Mg and RE on Microstructure and Properties of Hot Dip Galvanized Alloy Coatings

    Institute of Scientific and Technical Information of China (English)

    周英伟; 高波

    2017-01-01

    热浸镀技术是钢铁材料长效防腐的一种有效方法,因其可以显著提高钢铁材料的耐蚀性能、延长材料的使用寿命而被广泛应用.近年来,随着科技水平的不断提高,传统的热浸镀层已经无法满足市场多样化的需求,多元合金镀层的研究成为热浸镀领域的研究热点.随着研究的不断深入,人们发现在热浸镀过程中添加合金元素能够明显提高热浸镀层的综合性能,但是合金元素的加入是如何影响镀层组织结构及性能是值得探讨的问题.为此,详细介绍了硅、镁、稀土等合金元素的加入对热浸镀层的微观组织、耐蚀性能和耐蚀机理的影响.通过列举国内外的研究实例,进一步分析了合金元素的添加量对热浸镀层性能的影响规律.最后提出,继续研究各种合金元素及其添加量对热浸镀层组织性能的影响规律及机制,并深入探讨添加合金元素之后,合金镀层中金属间化合物层的形成和生长规律,开发性能优异的新型热浸镀层及相应的热浸镀工艺是未来热浸镀技术的主要研究方向.%Hot dipping technology is an effective method for long-term corrosion of steel materials, it has been widely used as it can significantly improve corrosion resistance of steel materials and extend service life of the materials. Recently, with the continuous improvement of technological level, traditional hot-dip coating has failed to meet the demands of market diversifica-tion, and study on multicomponent alloy coating has become a hotspot in the field of hot dipping. With the constant deepening of study, it was found that overall performance of hot-dip coating could be greatly improved by adding alloy elements in the hot dipping process could significantly improve the comprehensive performance of the hot-dip coating. However, it was worthy to discuss how addition of alloying elements affected coating microstructure and performance. The effects of the

  8. Powdering of Hot-dip Galvannealed steel using Finite Element Analysis

    International Nuclear Information System (INIS)

    Kim, D. W.; Jang, Y. C.; Lee, Y. S.; Kim, S. I.

    2007-01-01

    Demand for hot-dip galvannealed steel has been increased due to it high corrosion resistance, paintability, and formability in automotive industry. Coating of Hot-dip galvannealed steel consists of various Fe-Zn intermetallic compounds. Since the coating is hard and therefore it is very brittle, the surface of steel sheet is easy to be ruptured during second manufacturing processing. This is called as powdering. Hence, various research have been carried out to prohibit powdering for improving the quality of GA steel during second manufacturing processing. This paper performed finite element analysis to evaluate local powdering and compared FEA results with V-bending test. The effects of punch radius and coating strength on the powdering was examined

  9. Phase Transformation of Hot Dipped Aluminium during High Temperature Oxidation

    International Nuclear Information System (INIS)

    Zaifol Samsu; Muhammad Daud; Hishamuddin Husain; Mohd Saari Ripin; Rusni Rejab; Zaiton Selamat; Mohd Shariff Sattar

    2014-01-01

    Low alloy carbon steel was coated by hot-dipping into a molten aluminum bath. Isothermal oxidations were carried out at 750 degree Celsius in static air to study the oxidation behaviour of the hot-dipped aluminide steel. The phase transformation in the aluminide layer during diffusion at 750 degree Celsius in static air was analyzed by SEM-EDX and XRD. After hot-dip treatment, the coating layers consisted of three phases, where Al, thinner layer of FeAl 3 , and thicker layer of Fe 2 Al 5 were detected from external topcoat to the aluminide/ steel substrate. After oxidation, the Fe 2 Al 5 formed during the immersion process completely transformed to Fe 2 Al 5 , FeAl 2 , FeAl and Al-Fe(Al) phases because of the composition gradient and the chemical diffusion by oxidation. After oxidation, there are some voids were found at the coating/ substrate interface due to the rapid inter-diffusion of iron and aluminium during oxidation. The FeAl phase kept growing with increasing exposure time at 750 degree Celsius, while the Fe 2 Al 5 was consumed during oxidation. After 168 hrs oxidation, the Fe 2 Al 5 phase was going disappeared as the aluminum layer was consumed. (author)

  10. LongerLife products increase the sustainability. Is corrosion protection ecologically useful for steel components?; LongerLife-Produkte erhoehen die Nachhaltigkeit. Ist Korrosionsschutz von Stahlbauteilen oekologisch sinnvoll?

    Energy Technology Data Exchange (ETDEWEB)

    Rogall, Armin Dietmar [Fachhochschule Dortmund (Germany). Fachbereich Architektur

    2011-07-01

    The installation of hot-dip galvanized construction units means sustainable acting. Since corrosion protection by hot-dip galvanizing can be particularly named sustainable due to its longevity, its environmental careful production, its recycling ability and life extension of steel components. Particularly the reduction of the maintenance cycles and utilization costs accompanying with a slightly higher initial investment makes the hot-dip galvanizing a sustainable system. Steel components which are treated with galvanization and colour coating, have a maintenance-free life span of more than 80 years.

  11. 40 CFR 438.2 - General definitions.

    Science.gov (United States)

    2010-07-01

    ...; galvanizing/hot dip coating; hot dip coating; kerfing; laminating; mechanical and vapor plating; metallic... machining; vacuum impregnation; vacuum plating; water shedder; wet air pollution control; wire galvanizing...

  12. Diffusion Coefficient in the Zinc Coating Shaped on the Surface of Cast Iron and Steel Alloys

    Directory of Open Access Journals (Sweden)

    Kopyciński D.

    2015-06-01

    Full Text Available The article presents the method to assess the diffusion coefficient D in the sub-layer of intermetallic phases formed during hot-dip galvanizing “Armco” iron and ductile cast iron EN-GJS-500-7. Hot-dip galvanizing is one of the most popular forms of long-term protection of Fe-C alloys against corrosion. The process for producing a protective layer of sufficient quality is closely related to diffusion of atoms of zinc and iron. The simulation consist in performed a hot-dip galvanizing in laboratory condition above Fe-C alloys, in the Department of Engineering of Cast Alloys and Composites. Galvanizing time ranged from 15 to 300 seconds. Then metallographic specimens were prepared, intermetallic layers were measured and diffusion coefficient (D were calculated. It was found that the diffusion coefficient obtained during hot-dip galvanizing “Armco” iron and zinc is about two orders of magnitude less than the coefficient obtained on ductile cast iron EN-GJS-500-7.

  13. Analysis of the Inhibition Layer of Galvanized Dual-Phase Steels

    International Nuclear Information System (INIS)

    Wang, K. K.; Wang, H. P.; Chang, L.; Gan, D.; Chen, T. R.; Chen, H. B.

    2012-01-01

    The formation of the Fe-Al inhibition layer in hot-dip galvanizing is a confusing issue for a long time. This study presents a characterization result on the inhibition layer formed on C-Mn-Cr and C-Mn-Si dual-phase steels after a short time galvanizing. The samples were annealed at 800 .deg. C for 60 s in N 2 -10% H 2 atmosphere with a dew point of -30 .deg. C, and were then galvanized in a bath containing 0.2%Al. X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) was employed for characterization. The TEM electron diffraction shows that only Fe 2 Al 5 intermetallic phase was formed. No orientation relationship between the Fe 2 Al 5 phase and the steel substrate could be identified. Two peaks of Al 2p photoelectrons, one from metallic aluminum and the other from Al 3+ ions, were detected in the inhibition layer, indicating that the layer is in fact a mixture of Fe 2 Al 5 and Al 2 O 3 . TEM/EDS analysis verifies the existence of Al 2 O 3 in the boundaries of Fe 2 Al 5 grains. The nucleation of Fe 2 Al 5 and the reduction of the surface oxide probably proceeded concurrently on galvanizing, and the residual oxides prohibited the heteroepitaxial growth of Fe 2 Al 5

  14. Influence of stripping and cooling atmospheres on surface properties and corrosion of zinc galvanizing coatings

    Science.gov (United States)

    Yasakau, K. A.; Giner, I.; Vree, C.; Ozcan, O.; Grothe, R.; Oliveira, A.; Grundmeier, G.; Ferreira, M. G. S.; Zheludkevich, M. L.

    2016-12-01

    In this work the influence of stripping/cooling atmospheres used after withdrawal of steel sheet from Zn or Zn-alloy melt on surface properties of Zn (Z) and Zn-Al-Mg (ZM) hot-dip galvanizing coatings has been studied. The aim was to understand how the atmosphere (composed by nitrogen (N2) or air) affects adhesion strength to model adhesive and corrosive behaviour of the galvanized substrates. It was shown that the surface chemical composition and Volta potential of the galvanizing coatings prepared under the air or nitrogen atmosphere are strongly influenced by the atmosphere. The surface chemistry Z and ZM surfaces prepared under N2 contained a higher content of metal atoms and a richer hydroxide density than the specimens prepared under air atmosphere as assessed by X-ray photoelectron spectroscopy (XPS). The induced differences on the microstructure of the galvanized coatings played a key role on the local corrosion induced defects as observed by means of in situ Atomic force microscopy (AFM). Peel force tests performed on the substrates coated by model adhesive films indicate a higher adhesive strength to the surfaces prepared under nitrogen atmosphere. The obtained results have been discussed in terms of the microstructure and surface chemical composition of the galvanizing coatings.

  15. Corrosion protection pays off for coal-fired power plants

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, T.

    2006-11-15

    Zinc has long been used to hot-dip galvanise steel to deliver protection in harsh environments. Powder River Basin or eastern coal-fired plants benefit from using galvanized steel for conveyors, vibratory feeders, coal hoppers, chutes, etc. because maintenance costs are essentially eliminated. When life cycle costs for this process are compared to an alternative three-coal paint system for corrosion protection, the latter costs 5-10 times more than hot-dip galvanizing. An AEP Power Plant in San Juan, Puerto Rico and the McDuffie Coal Terminal in Mobile, AL, USA have both used hot-dip galvanized steel. 1 fig., 1 tab.

  16. Corrosion behaviour of hot dip zinc and zinc-aluminium coatings

    Indian Academy of Sciences (India)

    A comparative investigation of hot dip Zn–25Al alloy, Zn–55Al–Si and Zn coatings on steel was performed with attention to their corrosion performance in seawater. The results of 2-year exposure testing of these at Zhoushan test site are reported here. In tidal and immersion environments, Zn–25Al alloy coating is several ...

  17. The effects of RE and Si on the microstructure and corrosion resistance of Zn–6Al–3Mg hot dip coating

    International Nuclear Information System (INIS)

    Li, Shiwei; Gao, Bo; Yin, Shaohua; Tu, Ganfeng; Zhu, Guanglin; Sun, Shuchen; Zhu, Xiaoping

    2015-01-01

    Highlights: • ZAM coating has been prepared by using an experimental hot-dip galvanizing simulator. • The corrosion resistance of ZAM coating can be improved by additions of Si and RE. • Zn–6Al–3Mg–Si–RE coating forms a dense and stabilized corrosion product layer. • Zn–6Al–3Mg–Si–RE coating shows uniform corrosion. - Abstract: The effects of Si and RE on the microstructure and corrosion resistance of Zn–6Al–3Mg coating (ZAM) have been investigated. Surface morphology observations of the coating and corrosion products reveal that the additions of Si and rare earth metals (RES) improve the microstructural homogeneity of ZAMSR coating and stability of corrosion products formed on ZAMSR coating. Moreover, only uniform corrosion occurs in ZAMSR coating during the corrosion test, while intergranular corrosion and pitting occur in ZAM. As a result, the corrosion resistance of ZAM coating is improved by the additions of Si and RES.

  18. The effects of RE and Si on the microstructure and corrosion resistance of Zn–6Al–3Mg hot dip coating

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shiwei [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093 (China); School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Gao, Bo, E-mail: surfgao@aliyun.com [School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Yin, Shaohua [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093 (China); School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Tu, Ganfeng; Zhu, Guanglin; Sun, Shuchen; Zhu, Xiaoping [School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China)

    2015-12-01

    Highlights: • ZAM coating has been prepared by using an experimental hot-dip galvanizing simulator. • The corrosion resistance of ZAM coating can be improved by additions of Si and RE. • Zn–6Al–3Mg–Si–RE coating forms a dense and stabilized corrosion product layer. • Zn–6Al–3Mg–Si–RE coating shows uniform corrosion. - Abstract: The effects of Si and RE on the microstructure and corrosion resistance of Zn–6Al–3Mg coating (ZAM) have been investigated. Surface morphology observations of the coating and corrosion products reveal that the additions of Si and rare earth metals (RES) improve the microstructural homogeneity of ZAMSR coating and stability of corrosion products formed on ZAMSR coating. Moreover, only uniform corrosion occurs in ZAMSR coating during the corrosion test, while intergranular corrosion and pitting occur in ZAM. As a result, the corrosion resistance of ZAM coating is improved by the additions of Si and RES.

  19. Analysis of the Inhibition Layer of Galvanized Dual-Phase Steels

    Energy Technology Data Exchange (ETDEWEB)

    Wang, K. K.; Wang, H. P.; Chang, L.; Gan, D. [National Sun Yat-Sen Univ., Kaohsiung (China); Chen, T. R.; Chen, H. B. [Steel and Aluminum R and D Development, Kaohsiung (China)

    2012-01-15

    The formation of the Fe-Al inhibition layer in hot-dip galvanizing is a confusing issue for a long time. This study presents a characterization result on the inhibition layer formed on C-Mn-Cr and C-Mn-Si dual-phase steels after a short time galvanizing. The samples were annealed at 800 .deg. C for 60 s in N{sub 2}-10% H{sub 2} atmosphere with a dew point of -30 .deg. C, and were then galvanized in a bath containing 0.2%Al. X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) was employed for characterization. The TEM electron diffraction shows that only Fe{sub 2}Al{sub 5} intermetallic phase was formed. No orientation relationship between the Fe{sub 2}Al{sub 5} phase and the steel substrate could be identified. Two peaks of Al 2p photoelectrons, one from metallic aluminum and the other from Al{sup 3+} ions, were detected in the inhibition layer, indicating that the layer is in fact a mixture of Fe{sub 2}Al{sub 5} and Al{sub 2}O{sub 3}. TEM/EDS analysis verifies the existence of Al{sub 2}O{sub 3} in the boundaries of Fe{sub 2}Al{sub 5} grains. The nucleation of Fe{sub 2}Al{sub 5} and the reduction of the surface oxide probably proceeded concurrently on galvanizing, and the residual oxides prohibited the heteroepitaxial growth of Fe{sub 2}Al{sub 5}.

  20. Effect of Al Hot-Dipping on High-Temperature Corrosion of Carbon Steel in N2/0.1% H2S Gas

    Directory of Open Access Journals (Sweden)

    Muhammad Ali Abro

    2016-02-01

    Full Text Available High-temperature corrosion of carbon steel in N2/0.1% H2S mixed gas at 600–800 °C for 50–100 h was studied after hot-dipping in the aluminum molten bath. Hot-dipping resulted in the formation of the Al topcoat and the Al-Fe alloy layer firmly adhered on the substrate. The Al-Fe alloy layer consisted primarily of a wide, tongue-like Al5Fe2 layer and narrow Al3Fe layer. When corroded at 800 °C for 100 h, the Al topcoat partially oxidized to the protective but non-adherent α-Al2O3 layer, and the interdiffusion converted the Al-Fe alloy layer to an (Al13Fe4, AlFe3-mixed layer. The interdiffusion also lowered the microhardness of the hot-dipped steel. The α-Al2O3 layer formed on the hot-dipped steel protected the carbon steel against corrosion. Without the Al hot-dipping, the carbon steel failed by forming a thick, fragile, and non-protective FeS scale.

  1. Influence of Minor Alloying Elements on Selective Oxidation and Reactive Wetting of CMnSi TRIP Steel during Hot Dip Galvanizing

    Science.gov (United States)

    Cho, Lawrence; Kim, Myung Soo; Kim, Young Ha; De Cooman, Bruno C.

    2014-09-01

    The influence of the addition of minor alloying elements on the selective oxidation and the reactive wetting of CMnSi transformation-induced plasticity (TRIP) steels was studied by means of galvanizing simulator tests. Five TRIP steels containing small alloying additions of Cr, Ni, Ti, Cu, and Sn were investigated. After intercritical annealing (IA) at 1093 K (820 °C) in a N2 + 5 pct H2 gas atmosphere with a dew point of 213 K (-60 °C), two types of oxides were formed on the strip surface: Mn-rich xMnO·SiO2 ( x > 1.5) and Si-rich xMnO·SiO2 ( x galvanizing. The addition of a small amount of Sn is shown to significantly decrease the density of Zn-coating defects on CMnSi TRIP steels.

  2. About the influence of the topography of the steel surface on faults during hot galvanizing of part loads; Zum Einfluss der Topographie der Stahloberflaeche auf Fehler beim Stueckgut-Feuerverzinken

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, W.D. [Institut fuer Korrosionsschutz GmbH, Dresden (Germany); Schubert, P.

    2002-03-01

    The topography of the steel surface can influence the formation of layers during hot galvanizing in many ways. Information is given on galvanizing faults caused by impressions in the steel surface (rolling and drawing ridges). Flux remainders accumulated in these impressions can be encapsulated in the zinc coating during hot galvanizing. This leads to cavities and pores in the coating or to sponge-like zinc raisings at its surface. The flux remainders from the zinc coating can boil during powder coating and lead to blisters and pimple-like rises in the coating. Therefore, steel surfaces designed for galvanizing should be even or only have flat impressions. (orig.)

  3. Corrosion behaviour of hot dip zinc and zinc–aluminium coatings on ...

    Indian Academy of Sciences (India)

    Abstract. A comparative investigation of hot dip Zn–25Al alloy, Zn–55Al–Si and Zn coatings on steel was performed with attention to their corrosion performance in seawater. The results of 2-year exposure testing of these at Zhoushan test site are reported here. In tidal and immersion environments, Zn–25Al alloy coating is.

  4. Overall model of the dynamic behaviour of the steel strip in an annealing heating furnace on a hot-dip galvanizing line

    Directory of Open Access Journals (Sweden)

    Fernández, R.

    2010-10-01

    Full Text Available Predicting the temperature of the steel strip in the annealing process in a hot-dip galvanizing line (HDGL is important to ensure the physical properties of the processed material. The development of an accurate model that is capable of predicting the temperature the strip will reach according to the furnace’s variations in temperature and speed, its dimensions and the steel’s chemical properties, is a requirement that is being increasingly called for by industrial plants of this nature. This paper presents a comparative study made between several types of algorithms of Data Mining and Artificial Intelligence for the design of an efficient and overall prediction model that will allow determining the strip’s variation in temperature according to the physico-chemical specifications of the coils to be processed, and fluctuations in temperature and speed that are recorded within the annealing process. The ultimate goal is to find a model that is effectively applicable to coils of new types of steel or sizes that are being processed for the first time. This model renders it possible to fine-tune the control model in order to standardise the treatment in areas of the strip in which there is a transition between coils of different sizes or types of steel.La predicción de la temperatura de la banda de acero dentro del proceso de recocido de una planta de galvanizado continuo en caliente es importante para garantizar las propiedades físicas del material procesado. El desarrollo de un modelo preciso que sea capaz de predecir la temperatura que va a alcanzar la banda según las variaciones de temperaturas y velocidades del horno, y sus dimensiones y propiedades químicas del acero, es una necesidad cada vez más demandada por este tipo de plantas industriales. En el presente estudio se muestra una comparativa realizada entre diversos tipos de algoritmos deMinería de Datos e Inteligencia Artificial para el desarrollo de un modelo de predicci

  5. Selective Oxidation and Reactive Wetting during Galvanizing of a CMnAl TRIP-Assisted Steel

    Science.gov (United States)

    Bellhouse, E. M.; McDermid, J. R.

    2011-09-01

    A transformation induced plasticity (TRIP)-assisted steel with 0.2 pct C, 1.5 pct Mn, and 1.5 pct Al was successfully galvanized using a thermal cycle previously shown to produce an excellent combination of strength and ductility. The steel surface chemistry and oxide morphology were determined as a function of process atmosphere oxygen partial pressure. For the 220 K (-53 °C) dew point (dp) + 20 pct H2 atmosphere, the oxide morphology was a mixture of films and nodules. For the 243 K (-30 °C) dp + 5 pct H2 atmosphere, nodules of MnO were found primarily at grain boundaries. For the 278 K (+5 °C) dp + 5 pct H2 atmosphere, nodules of metallic Fe were found on the surface as a result of alloy element internal oxidation. The steel surface chemistry and oxide morphology were then related to the reactive wetting behavior during continuous hot dip galvanizing. Good wetting was obtained using the two lower oxygen partial pressure process atmospheres [220 K dp and 243 K dp (-53 °C dp and -30 °C dp)]. An increase in the number of bare spots was observed when using the higher oxygen partial pressure process atmosphere (+5 °C dp) due to the increased thickness of localized oxide films.

  6. DFI oxyfuel process for saving energy and improving the performance and quality of continuous strip lines; DFI-Oxyfuel-Verfahren zur Energieeinsparung, Leistungs- und Qualitaetssteigerung von Banddurchlaufanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Eichelkraut, H. [ThyssenKrupp Steel AG, Duisburg (Germany). Standort Bruckhausen; Heiler, H.J. [ThyssenKrupp Steel AG, Finnentrop (Germany); Domels, H.P.; Hoegner, W. [ThyssenKrupp Steel AG, Duisburg (Germany). Energie/Anlagenwirtschaft

    2007-07-01

    The development of the 'Direct Flame Impingement (DFI)-Oxyfuel' process - in which an oxyfuel (oxygen-fuel) flame impinges directly on the material to be heated - represents a further development of furnace technology for continuous strip lines. With assistance from the cooperation partner Linde, the process was used on a hot-dip galvanizing line for the first time at ThyssenKrupp Steel's Finnentrop plant. Right from the start it produced outstanding results in terms of increased throughput, product quality, plant quality and energy efficiency and thus also a reduction in direct CO{sub 2} emissions. In the meantime, this technology also is being used at an additional strip galvanizing and aluminizing facility in the Duisburg-Bruckhausen plant. (orig.)

  7. Selective Oxidation and Reactive Wetting During Hot-Dip Galvanizing of a 1.0 pct Al-0.5 pct Si TRIP-Assisted Steel

    Science.gov (United States)

    Bellhouse, E. M.; McDermid, J. R.

    2012-07-01

    Selective oxidation and reactive wetting during continuous galvanizing were studied for a low-alloy transformation induced plasticity (TRIP)-assisted steel with 0.2 pct C, 1.5 pct Mn, 1.0 pct Al and 0.5 pct Si. Three process atmospheres were tested during annealing prior to galvanizing: 220 K (-53 °C) dew point (dp) N2-20 pct H2, 243 K (-30 °C) dp N2-5 pct H2 and 278 K (+5 °C) dp N2-5 pct H2. The process atmosphere oxygen partial pressure affected the oxide chemistry, morphology and thickness. For the 220 K (-53 °C) dp and 243 K (-30 °C) dp process atmospheres, film and nodule-type manganese, silicon and aluminum containing oxides were observed at the surface. For the 278 K (+5 °C) dp atmosphere, MnO was observed at the grain boundaries and as thicker localized surface films. Oxide morphology, thickness and chemistry affected reactive wetting, with complete wetting being observed for the 220 K (-53 °C) dp and 243 K (-30 °C) dp process atmospheres and incomplete reactive wetting being observed for the 278 K (+5 °C) dp atmosphere. Complete reactive wetting for the 220 K (-53 °C) dp and 243 K (-30 °C) dp process atmospheres was attributed to a combination of zinc bridging of oxides, aluminothermic reduction of surface oxides and wetting of the oxides. Incomplete wetting for the 278 K (+5 °C) dp atmosphere was attributed to localized thick MnO films.

  8. Influence of stripping and cooling atmospheres on surface properties and corrosion of zinc galvanizing coatings

    International Nuclear Information System (INIS)

    Yasakau, K.A.; Giner, I.; Vree, C.; Ozcan, O.; Grothe, R.; Oliveira, A.; Grundmeier, G.; Ferreira, M.G.S.; Zheludkevich, M.L.

    2016-01-01

    Highlights: • Stripping/cooling atmosphere affects surfaces chemical composition of Zn and Zn-Al-Mg galvanized coatings. • Higher peel forces of model adhesive films were obtained on zinc alloys samples prepared under nitrogen atmosphere. • Localized corrosion attack originates at grain boundaries on Zn galvanized coating. • Visible dissolution of MgZn_2 phase was observed by in situ AFM only at binary eutectics and not at ternary ones. - Abstract: In this work the influence of stripping/cooling atmospheres used after withdrawal of steel sheet from Zn or Zn-alloy melt on surface properties of Zn (Z) and Zn-Al-Mg (ZM) hot-dip galvanizing coatings has been studied. The aim was to understand how the atmosphere (composed by nitrogen (N_2) or air) affects adhesion strength to model adhesive and corrosive behaviour of the galvanized substrates. It was shown that the surface chemical composition and Volta potential of the galvanizing coatings prepared under the air or nitrogen atmosphere are strongly influenced by the atmosphere. The surface chemistry Z and ZM surfaces prepared under N_2 contained a higher content of metal atoms and a richer hydroxide density than the specimens prepared under air atmosphere as assessed by X-ray photoelectron spectroscopy (XPS). The induced differences on the microstructure of the galvanized coatings played a key role on the local corrosion induced defects as observed by means of in situ Atomic force microscopy (AFM). Peel force tests performed on the substrates coated by model adhesive films indicate a higher adhesive strength to the surfaces prepared under nitrogen atmosphere. The obtained results have been discussed in terms of the microstructure and surface chemical composition of the galvanizing coatings.

  9. Microscopic analysis and simulation of check-mark stain on the galvanized steel strip

    Science.gov (United States)

    So, Hongyun; Yoon, Hyun Gi; Chung, Myung Kyoon

    2010-11-01

    When galvanized steel strip is produced through a continuous hot-dip galvanizing process, the thickness of adhered zinc film is controlled by plane impinging air gas jet referred to as "air-knife system". In such a gas-jet wiping process, stain of check-mark or sag line shape frequently appears. The check-mark defect is caused by non-uniform zinc coating and the oblique patterns such as "W", "V" or "X" on the coated surface. The present paper presents a cause and analysis of the check-mark formation and a numerical simulation of sag lines by using the numerical data produced by Large Eddy Simulation (LES) of the three-dimensional compressible turbulent flow field around the air-knife system. It was found that there is alternating plane-wise vortices near the impinging stagnation region and such alternating vortices move almost periodically to the right and to the left sides on the stagnation line due to the jet flow instability. Meanwhile, in order to simulate the check-mark formation, a novel perturbation model has been developed to predict the variation of coating thickness along the transverse direction. Finally, the three-dimensional zinc coating surface was obtained by the present perturbation model. It was found that the sag line formation is determined by the combination of the instantaneous coating thickness distribution along the transverse direction near the stagnation line and the feed speed of the steel strip.

  10. Cross Coating Weight Control by Electromagnetic Strip Stabilization at the Continuous Galvanizing Line of ArcelorMittal Florange

    Science.gov (United States)

    Guelton, Nicolas; Lopès, Catherine; Sordini, Henri

    2016-08-01

    In hot dip galvanizing lines, strip bending around the sink roll generates a flatness defect called crossbow. This defect affects the cross coating weight distribution by changing the knife-to-strip distance along the strip width and requires a significant increase in coating target to prevent any risk of undercoating. The already-existing coating weight control system succeeds in eliminating both average and skew coating errors but cannot do anything against crossbow coating errors. It has therefore been upgraded with a flatness correction function which takes advantage of the possibility of controlling the electromagnetic stabilizer. The basic principle is to split, for every gage scan, the coating weight cross profile of the top and bottom sides into two, respectively, linear and non-linear components. The linear component is used to correct the skew error by realigning the knives with the strip, while the non-linear component is used to distort the strip in the stabilizer in such a way that the strip is kept flat between the knives. Industrial evaluation is currently in progress but the first results have already shown that the strip can be significantly flattened between the knives and the production tolerances subsequently tightened without compromising quality.

  11. Influence of stripping and cooling atmospheres on surface properties and corrosion of zinc galvanizing coatings

    Energy Technology Data Exchange (ETDEWEB)

    Yasakau, K.A., E-mail: kyasakau@ua.pt [Department of Materials and Ceramic Engineering, CICECO—Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro (Portugal); Giner, I. [Universität Paderborn, Fakultät NW—Department Chemie, Technische und Makromolekulare Chemie, Warburger Strasse 100, D-33098 Paderborn (Germany); Vree, C. [Salzgitter Mannesmann Forschung, GmbH Division Surface Technology, Eisenhüttenstrasse 99, 38239 Salzgitter (Germany); Ozcan, O.; Grothe, R. [Universität Paderborn, Fakultät NW—Department Chemie, Technische und Makromolekulare Chemie, Warburger Strasse 100, D-33098 Paderborn (Germany); Oliveira, A. [Department of Materials and Ceramic Engineering, CICECO—Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro (Portugal); Grundmeier, G. [Universität Paderborn, Fakultät NW—Department Chemie, Technische und Makromolekulare Chemie, Warburger Strasse 100, D-33098 Paderborn (Germany); Ferreira, M.G.S. [Department of Materials and Ceramic Engineering, CICECO—Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro (Portugal); Zheludkevich, M.L. [Department of Materials and Ceramic Engineering, CICECO—Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro (Portugal); Department of Corrosion and Surface Technology, Institute of Materials Research Helmholtz-Zentrum Geesthacht, Max-Planck Str. 1, 21502 Geesthacht (Germany)

    2016-12-15

    Highlights: • Stripping/cooling atmosphere affects surfaces chemical composition of Zn and Zn-Al-Mg galvanized coatings. • Higher peel forces of model adhesive films were obtained on zinc alloys samples prepared under nitrogen atmosphere. • Localized corrosion attack originates at grain boundaries on Zn galvanized coating. • Visible dissolution of MgZn{sub 2} phase was observed by in situ AFM only at binary eutectics and not at ternary ones. - Abstract: In this work the influence of stripping/cooling atmospheres used after withdrawal of steel sheet from Zn or Zn-alloy melt on surface properties of Zn (Z) and Zn-Al-Mg (ZM) hot-dip galvanizing coatings has been studied. The aim was to understand how the atmosphere (composed by nitrogen (N{sub 2}) or air) affects adhesion strength to model adhesive and corrosive behaviour of the galvanized substrates. It was shown that the surface chemical composition and Volta potential of the galvanizing coatings prepared under the air or nitrogen atmosphere are strongly influenced by the atmosphere. The surface chemistry Z and ZM surfaces prepared under N{sub 2} contained a higher content of metal atoms and a richer hydroxide density than the specimens prepared under air atmosphere as assessed by X-ray photoelectron spectroscopy (XPS). The induced differences on the microstructure of the galvanized coatings played a key role on the local corrosion induced defects as observed by means of in situ Atomic force microscopy (AFM). Peel force tests performed on the substrates coated by model adhesive films indicate a higher adhesive strength to the surfaces prepared under nitrogen atmosphere. The obtained results have been discussed in terms of the microstructure and surface chemical composition of the galvanizing coatings.

  12. Characterization of Sludge from the Process of Steel Tubes Chemical Treatment for Hot Galvanizing

    Directory of Open Access Journals (Sweden)

    Sofilić, U.

    2009-10-01

    Full Text Available Inadequate industrial waste management in Croatia is reflected in the non-sanitary waste disposal, low recycling levels, negligible share of waste processing technologies, insufficient control of its flows, etc.Generated industrial wastes are most frequently disposed of at producers’ own, mostly illegal landfills. There are many such landfills on the Croatian territory, and the disposed types of waste often include those that can be hazardous and represent a considerable source of environmental pollution.Past waste management in all industrial branches can be characterized in this way, which at the same time may result in the harmful impact on human health and the environment. It also represents economic loss due to low utilisation of material and energy potential of some industrial wastes. The metallurgical industry collects its production waste separately. Only a part of the generated waste is returned to the production process and some waste is occasionally used by other industries as secondary raw materials, but the largest part of it ends at producers' own landfills on site. Hazardous wastes (dust containing heavy metals, waste oils etc. are mostly disposed of in a controlled and lawful manner. Past handling of metallurgical waste was unacceptable both from the environmental and economic point of view. Therefore a systematic resolving of this important issue was initiated at the beginning of this decade. Sisak Steelworks galvanized steel pipes in the hot-dip galvanizing procedure by immersing in molten zinc. Between 1970 and 2000 Sisak Steelworks produced approximately 900 000 tonnes of galvanized pipes this way and generated around 70 000 m3 of neutralisation sludge, which was subsequently disposed of in the landfill on site. The paper presents the results of examination of physical-chemical properties of neutralisation sludge generated as waste material in the process of neutralisation of waste sulphate acid bath used in Sisak

  13. Corrosion behaviour and biocorrosion of galvanized steel water distribution systems.

    Science.gov (United States)

    Delaunois, F; Tosar, F; Vitry, V

    2014-06-01

    Galvanized steel tubes are a popular mean for water distribution systems but suffer from corrosion despite their zinc or zinc alloy coatings. First, the quality of hot-dip galvanized (HDG) coatings was studied. Their microstructure, defects, and common types of corrosion were observed. It was shown that many manufactured tubes do not reach European standard (NBN EN 10240), which is the cause of several corrosion problems. The average thickness of zinc layer was found at 41μm against 55μm prescribed by the European standard. However, lack of quality, together with the usual corrosion types known for HDG steel tubes was not sufficient to explain the high corrosion rate (reaching 20μm per year versus 10μm/y for common corrosion types). Electrochemical tests were also performed to understand the corrosion behaviours occurring in galvanized steel tubes. Results have shown that the limiting step was oxygen diffusion, favouring the growth of anaerobic bacteria in steel tubes. EDS analysis was carried out on corroded coatings and has shown the presence of sulphur inside deposits, suggesting the likely bacterial activity. Therefore biocorrosion effects have been investigated. Actually sulphate reducing bacteria (SRB) can reduce sulphate contained in water to hydrogen sulphide (H2S), causing the formation of metal sulphides. Although microbial corrosion is well-known in sea water, it is less investigated in supply water. Thus, an experimental water main was kept in operation for 6months. SRB were detected by BART tests in the test water main. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Advanced cold rolled steels for automotive applications

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Harald; Mattissen, Dorothea; Schaumann, Thomas Wilhelm [ThyssenKrupp Steel AG, Center of Materials Excellence, Dortmund (Germany)

    2009-01-15

    Advanced high-strength steels offer a great potential for the further development of automobile bodies-in-white due to their combined mechanical properties of high formability and strength. They represent the first choice in material selection for strength and crash-relevant parts with challenging geometries. The intensive development of multiphase steels by ThyssenKrupp Steel has led to hot dip galvanizing concepts with an outstanding forming potential. Hot rolled, hot dip galvanized complex-phase steels are currently produced in addition to cold rolled dual phase (DP) and retained austenite (RA) or transformation induced plasticity (TRIP) steels. New continuously annealed grades of steel are being developed with tensile strength levels of up to 1000 MPa in combination with sufficient ductility for the high demands of structural automobile components. These steels make use of the classic advantages of microalloying as well as the principles of DP steels and RA / TRIP steels. Further improvement of properties will be reached by the new class of high manganese alloyed steels. (orig.)

  15. Shaping optimal zinc coating on the surface of high-quality ductile iron casting. Part I – Moulding technologies vs. zinc coating

    Directory of Open Access Journals (Sweden)

    Szczęsny A.

    2017-03-01

    Full Text Available Studies have demonstrated that in the process of hot dip galvanizing the decisive influence on the mechanism of zinc coating formation and properties has the quality of the mechanically untreated (raw surface layer of the galvanized product. The terms “casting surface layer” denote various parameters of the microstructure, including the type of metal matrix, the number of grains and the size of graphite nodules, possible presence of hard spots (the precipitates of eutectic cementite and parameters of the surface condition. The completed research has allowed linking the manufacturing technology of ductile iron castings with the process of hot dip galvanizing.

  16. REMOVING ZINC FROM GALVANIZED STEEL SCRAP TO FEASIBLE THE BOF SLUDGE RECYCLING

    Directory of Open Access Journals (Sweden)

    Mônica Marques Caetano de Lima

    2013-06-01

    Full Text Available Galvanized steel scraps generated at Usiminas Ipatinga are recycled in BOF converters. Although they are noble products, they contain a significant quantity of zinc that escapes from the bath due to its high vapor pressure and is captured by the gas control system, appearing in BOF sludge. As BOF sludge contains high iron content, it could be recycled to the process, but due to its zinc content, it is disposed in landfills. For this reason, this study aimed to treat these scraps to remove zinc layer using a thermal treatment process. The samples were fed to a rotative furnace in an inert ambient. It was tested the hot dip galvanized and eletrogalvanized scraps, varying the zinc coating weight between 20g/m2 and 150g/m2, temperature between 700°C and 900°C and time between 3 minutes and 10 minutes. Considering these conditions, it is verified that more than 70% of the zinc layer is removed at 700°C, in 10 minutes. Dust captured is about 60% of metallic zinc and 40% as zinc oxide. Based on these results, the recycling of BOF sludge can be feasible to the ironmaking process.

  17. Preparation and characterization of 304 stainless steel/Q235 carbon steel composite material

    Science.gov (United States)

    Shen, Wenning; Feng, Lajun; Feng, Hui; Cao, Ying; Liu, Lei; Cao, Mo; Ge, Yanfeng

    The composite material of 304 stainless steel reinforced Q235 carbon steel has been prepared by modified hot-rolling process. The resulted material was characterized by scanning electron microscope, three-electrode method, fault current impact method, electrochemical potentiodynamic polarization curve measurement and electrochemical impedance spectroscopy. The results showed that metallurgical bond between the stainless steel layer and carbon steel substrate has been formed. The composite material exhibited good electrical conductivity and thermal stability. The average grounding resistance of the composite material was about 13/20 of dip galvanized steel. There has no surface crack and bubbling formed after fault current impact. The composite material led to a significant decrease in the corrosion current density in soil solution, compared with that of hot dip galvanized steel and bare carbon steel. On the basis polarization curve and EIS analyses, it can be concluded that the composite material showed improved anti-corrosion property than hot-dip galvanized steel.

  18. 46 CFR 160.035-3 - Construction of steel oar-propelled lifeboats.

    Science.gov (United States)

    2010-10-01

    ... apparatus shall have a minimum factor of safety of six. (2) For construction and capacity of disengaging... shall be galvanized by the hot dipped process. All fabricated pieces or sections are to be galvanized...

  19. The influence of alloying elements on the hot-dip aluminizing process and on the subsequent high-temperature oxidation

    International Nuclear Information System (INIS)

    Glasbrenner, H.; Nold, E.; Voss, Z.

    1997-01-01

    For hot dip aluminizing HDA an Al melt was doped with one of the elements Mo, W or Nb with a nominal composition of about 1 wt%. In case of W, the nominal composition was achieved, not so for Mo and Nb. The influence of these elements on the coating formed and on the following oxidation process was investigated. Hot dip aluminizing was carried out at 800 C for 5 min under dry Ar atmosphere. The oxidation experiments were performed at 950 C for 24 h in air. Compared to the HDA processes with pure Al, the addition of the alloying elements lead to thinner intermetallic layers. A change in the oxidation behavior was observed as well concerning the suppression of internal oxidation and the formation of dense and close oxide scales. (orig.)

  20. The morphology of coating/substrate interface in hot-dip-aluminized steels

    International Nuclear Information System (INIS)

    Awan, Gul Hameed; Hasan, Faiz ul

    2008-01-01

    In hot-dip-aluminized (HAD) steels, the morphology and the profile of the interface between the aluminum coating and the substrate steel, are affected both by the composition of the molten aluminum as well as by the composition, and even the microstructure, of the substrate steel. This effect has been investigated using optical and scanning electron microscopy, and X-ray diffraction. The reaction between the steel and the molten aluminum leads to the formation of Fe-Al inter-metallic compounds on the steel surface. The thickness of the inter-metallic compound layer as well as the morphology of the interface between the steel and the interlayer varies with the silicon content of the molten aluminum. In hot-dip-aluminizing with pure aluminum, the interlayer is 'thick' and exhibits a finger-like growth into the steel. With a gradually increasing addition of silicon into the aluminum melt, the thickness of the interlayer decreases while the interface between the interlayer and the substrate gradually becomes 'smoother'. With an increase in the carbon content of the substrate steel the growth of the interlayer into the steel is impeded by the pearlite phase, whereas the ferrite phase appears to dissolve more readily. X-ray diffraction and electron microscopic studies showed that the interlayer formed in samples aluminized in pure aluminum, essentially consisted of orthorhombic Fe 2 Al 5 . It was further observed that the finger-like grains of Fe 2 Al 5 phase exhibited a preferred lattice orientation. With a gradual addition of silicon into the aluminum melt, a cubic phase based on Fe 3 Al also started to form in the interlayer and replaced most of the Fe 2 Al 5

  1. Annealing treatments for producing cold-rolled low-silicon multi-phase steels for automotive applications

    Energy Technology Data Exchange (ETDEWEB)

    Vrieze, J.; Vortrefflich, W.; Winter, L. de [Applied Physical Metallurgy, Hoogovens Research and Development, Ijmuiden (Netherlands)

    2000-07-01

    Laboratory simulations of a hot-dip galvanizing line have been carried out on a 0.16%C-1.5%Mn-0.4%Si steel. It has been demonstrated that based on this steel composition materials with typical multi-phase properties can be produced on hot-dip galvanizing lines. By varying the process conditions a tensile strength between 570 and 650 MPa has been obtained. In addition, tensile tests at high strain rates have been carried out and the results have been compared with those of other non-multi-phase steel grades. (orig.)

  2. Effect of zinc crystals size on galvanized steel deformation and electrochemical behavior

    Directory of Open Access Journals (Sweden)

    José Daniel Culcasi

    2009-09-01

    Full Text Available Hot-dip galvanized steel sheets with different spangle sizes were deformed by means of rolling and tension. The change of preferential crystallographic orientation and of superficial characteristics due to the deformation was analyzed by means of both X-rays diffraction and optical and scanning electronic microscopy. A correlation between such changes and the involving deformation modes was intended to be done and the spangle size influence on these modes was studied. Coating reactivity change due to the deformation was investigated by means of quasi-steady DC electrochemical tests. The results allow to infer that, in great spangle samples, the main deformation mechanism is twinning whereas in small spangle ones, pyramidal slip systems happen as well. The increase of the reactivity with the deformation is greater in tension than in rolling and it is more important in small than in great spangle samples.

  3. Hot-dipped tin-zinc on U-0.75 w/o Ti

    International Nuclear Information System (INIS)

    Weirick, L.J.

    1979-09-01

    Conventional Zn galvanizing of U-0.75 Ti results in nonuniform coatings and reduced elongation because of thermal aging of the surface of the U-Ti. A lower melting material which would give sacrificial galvanic protection to the U-Ti was found in the Sn-Zn alloy system. The present work describes: (1) the metallography of the Sn-Zn system, (2) the electrochemistry of the Sn-Zn system with respect to U-Ti, (3) the mechanics of applying a Sn-Zn coating to U-Ti, (4) salt spray corrosion test results of various Sn-Zn alloys applied to U-Ti coupons, and (5) mechanical property tests of coated U-Ti tensile bars. An 80 Sn-20 Zn alloy (MP-280 0 C) was chosen for the galvanizing study because of its lower melting point. The results showed that all alloys of the Sn-Zn system galvanically protected the U-Ti in salt fog environments. The lack of a suitable low temperature flux prevented the operation of the Sn-Zn bath at its optimum temperature and low elongations were obtained with this coating system

  4. Cold laminar galvanizing: a new anti-corrosion concept

    International Nuclear Information System (INIS)

    Bagnulo, L.H.

    1984-01-01

    Cold laminar galvanizing, a recent anticorrosion technology, now combines the most positive characteristics of the hot galvanizing protective systems. This patented technology has a zinc laminated foil (obtained by processing 99.9% pure zinc ingots) that is homogeneous and isotropic, with a standard thickness of 80-100μm. This foil is backed with an electro-conductive, selfadhesive glue prepared under an original formula. The zinc laminated foil offers excellent anchorage and elevated resistance to the main atmospheric agents

  5. Preparation and characterization of 304 stainless steel/Q235 carbon steel composite material

    Directory of Open Access Journals (Sweden)

    Wenning Shen

    Full Text Available The composite material of 304 stainless steel reinforced Q235 carbon steel has been prepared by modified hot-rolling process. The resulted material was characterized by scanning electron microscope, three-electrode method, fault current impact method, electrochemical potentiodynamic polarization curve measurement and electrochemical impedance spectroscopy. The results showed that metallurgical bond between the stainless steel layer and carbon steel substrate has been formed. The composite material exhibited good electrical conductivity and thermal stability. The average grounding resistance of the composite material was about 13/20 of dip galvanized steel. There has no surface crack and bubbling formed after fault current impact. The composite material led to a significant decrease in the corrosion current density in soil solution, compared with that of hot dip galvanized steel and bare carbon steel. On the basis polarization curve and EIS analyses, it can be concluded that the composite material showed improved anti-corrosion property than hot-dip galvanized steel. Keywords: Stainless steel, Carbon steel, Anti-corrosion, Conductivity, Electrochemical, EIS

  6. Effect of Continuous Galvanizing Heat Treatments on the Microstructure and Mechanical Properties of High Al-Low Si Transformation Induced Plasticity Steels

    Science.gov (United States)

    Bellhouse, E. M.; McDermid, J. R.

    2010-02-01

    Heat treatments were performed using an isothermal bainitic transformation (IBT) temperature compatible with continuous hot-dip galvanizing on two high Al-low Si transformation induced plasticity (TRIP)-assisted steels. Both steels had 0.2 wt pct C and 1.5 wt pct Mn; one had 1.5 wt pct Al and the other had 1 wt pct Al and 0.5 wt pct Si. Two different intercritical annealing (IA) temperatures were used, resulting in intercritical microstructures of 50 pct ferrite (α)-50 pct austenite (γ) and 65 pct α-35 pct γ. Using the IBT temperature of 465 °C, five IBT times were tested: 4, 30, 60, 90, and 120 seconds. Increasing the IBT time resulted in a decrease in the ultimate tensile strength (UTS) and an increase in the uniform elongation, yield strength, and yield point elongation. The uniform elongation was higher when using the 50 pct α-50 pct γ IA temperature when compared to the 65 pct α-35 pct γ IA temperature. The best combinations of strength and ductility and their corresponding heat treatments were as follows: a tensile strength of 895 MPa and uniform elongation of 0.26 for the 1.5 pct Al TRIP steel at the 50 pct γ IA temperature and 90-second IBT time; a tensile strength of 880 MPa and uniform elongation of 0.27 for the 1.5 pct Al TRIP steel at the 50 pct γ IA temperature and 120-second IBT time; and a tensile strength of 1009 MPa and uniform elongation of 0.22 for the 1 pct Al-0.5 pct Si TRIP steel at the 50 pct γ IA temperature and 120-second IBT time.

  7. Benchmarking of Zinc Coatings for Corrosion Protection: A Detailed Characterization of Corrosion and Electrochemical Properties of Zinc Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Wijesinghe, Sudesh L; Zixi, Tan [Singapore Institute of Manufacturing Technology, Nanyang Drive (Singapore)

    2017-02-15

    Due to various types of Zn coatings for many decades for various applications, it is imperative to study and compare their corrosion resistance properties of some of these. Here, we introduce a systematic methodology for evaluation and validation of corrosion protection properties of metallic coatings. According to this methodology, samples are were exposed in an advanced cyclic corrosion test chamber according to ISO 14993, and removed at the end of each withdrawal for respective corrosion and electrochemical characterization to evaluate both barrier and galvanic protection properties. Corrosion protection properties of coatings were evaluated by visual examination according to ISO 10289, mass loss and subsequent corrosion rate measurements, electrochemical properties, and advanced electrochemical scanning techniques. In this study, corrosion protection properties of a commercial zinc rich coating (ZRC) on AISI 1020 mild steel substrates were evaluated and benchmarked against hot dip galvanized (HDG). Results were correlated, and corrosion protection capabilities of the two coatings were compared. The zinc rich coating performed better than hot dip galvanized coating in terms of overall corrosion protection properties, according to the exposure and experimental conditions used in this study. It proved to be a suitable candidate to replace hot dip galvanized coatings for desired applications.

  8. Forming of High-strength Steels Using a Hot-melt Dry Lubricant

    DEFF Research Database (Denmark)

    Hörnström, Sven-Erik; Karlsson, Erik; Olsson, Mikael

    2008-01-01

    during forming resulting in seizure of the tool/steel sheet contact and extensive scratching of the steel sheet surface. As a result, a number of concepts have been developed in order to reduce the tendency to galling in metal forming, including the development of new dry lubricants, new forming tool...... steel grades and improved surface engineering treatments such as the deposition of low friction CVD and PVD coatings. In the present study the performance of a hot-melt dry lubricant in the forming of hot and cold rolled and hot-dip galvanized high strength steel has been evaluated and compared...... with a conventional rust protection oil using four different tests methods, i.e. a strip reduction test, a bending under tension test, a stretch-forming test and a pin-on disc test. In the tests, two different cold work tool steels, a conventional steel grade and a nitrogen alloyed PM steel grade were evaluated...

  9. Dip-slope and Dip-slope Failures in Taiwan - a Review

    Science.gov (United States)

    Lee, C.

    2011-12-01

    Taiwan is famous for dip-slope and dip-slope slides. Dip-slopes exist at many places in the fold-and-thrust belt of Taiwan. Under active cutting of stream channels and man-made excavations, a dip-slope may become unstable and susceptible for mass sliding. Daylight of a bedding parallel clay seam is the most dangerous type for dip-slope sliding. Buckling or shear-off features may also happen at toe of a long dip-slope. Besides, a dip-slope is also dangerous for shallow debris slides, if the slope angle is between 25 to 45 degrees and the debris (colluvium or slope wash) is thick (>1m). These unstable slopes may slide during a triggering event, earthquake or typhoon storm; or even slide without a triggering event, like the 2010 Tapu case. Initial buckling feature had been found in the dip-slope of the Feitsui arch dam abutment after detailed explorations. Shear-off feature have also been found in dip-slope located in right bank of the Nahua reservoir after field investigation and drilling. The Chiufengerhshan slide may also be shear-off type. On the other hand, the Tapu, the Tsaoling slides and others are of direct slide type. The Neihoo Bishan slide is a shallow debris slide on dip-slope. All these cases demonstrate the four different types of dip-slope slide. The hazard of a dip-slope should be investigated to cover these possible types of failure. The existence of bedding parallel clay seams is critical for the stability of a dip-slope, either for direct slide or buckling or shear-off type of failure, and is a hot point during investigation. Because, the stability of a dip-slope is changing with time, therefore, detailed explorations to including weathering and erosion rates are also very necessary to ensure the long-term stability of a dip-slope.

  10. Origin of intragranular crystallographic misorientations in hot-dip Al-Zn-Si coatings

    International Nuclear Information System (INIS)

    Niederberger, Ch.; Michler, J.; Jacot, A.

    2008-01-01

    The origin of intragranular variations of the crystallographic orientation in hot-dip Al-Zn-Si coatings is discussed based on new experimental results and modelling. The solidification microstructure in as-received 55Al-43.4Zn-1.6Si (in wt.%) coatings deposited on steel plates in an industrial production line was analyzed by electron backscattered diffraction, glow-discharge optical emission spectroscopy and atomic force microscopy (AFM). The results were compared with those obtained in coatings re-solidified under different cooling and mechanical loading conditions. Continuous variations of the crystallographic orientation as large as 35 deg. were observed within individual grains of Al-Zn-Si, consistent with previous studies. However, the mechanisms previously proposed for the origin of intragranular crystallographic misorientations had to be revisited. The new experimental data acquired during this study indicate that the solidification shrinkage accumulating in the area of the grain envelope is the driving force for the formation of intragranular misorientations. The solidification shrinkage leads to the development of tensile stresses in the oxide film covering the coating while it solidifies. Estimations based on AFM profiles and phase field simulations of the dendritic structure indicate that the stresses applied on the dendrite network are sufficient to deform plastically the dendrite arms during solidification

  11. Influence of hot water dip and gamma irradiation on postharvest fungal decay of Galia melons

    International Nuclear Information System (INIS)

    Barkai-Golan, R.; Padova, R.; Ross, I.; Lapidot, M.; Copel, A.; Davidson, H.

    1993-01-01

    Dipping Galia melons in hot water at 52 deg C for 5 min or at 55 deg for 2 min resulted in 12-15% decay (caused by Alternaria alternata, Fusarium spp. and Trichothecium roseum) during prolonged storage (12 d at 6 deg plus 3 d at 18 deg ) compared with 75% decay in untreated fruit or 60% decay in cold-water-dipped fruit. Irradiation at 0.5 or 1 kGy had no significant effect on decay development. However, combination of heat treatment with a 0.5 kGy dose prevented fungal growth, resulting in 5% decay during storage. Combinations of heating with 1 kGy irradiation gave no improvement in anti-fungal effect over treatment with 0.5 kGy and sometimes resulted in a decreased suppressive effect. Reducing the duration of dipping at 55 deg from 2 to 0.5 min, applied alone or in combination with irradiation, considerably reduced the anti-fungal effect of the treatment. The effective combined treatment resulted in 12-15% of slight peel damage, but all the fruits were regarded as marketable. No differences in fruit firmness were recorded among the treatments

  12. Identification of Intermetallic Compounds and Its Formation Mechanism in Boron Steel Hot-Dipped in Al-7 wt.% Mn Alloy

    Directory of Open Access Journals (Sweden)

    Sung-Yun Kwak

    2017-12-01

    Full Text Available In laser welding and hot stamping Al-Si-coated boron steel, there is a problem that the strength of the joint is lowered due to ferrite formation in the fusion zone. The purpose of this study is to develop an Al-7 wt.% Mn hot-dip coating in which Mn, an austenite stabilizing element, replaces the ferrite stabilizing element Si. The nucleation and formation mechanism of the reaction layer was studied in detail by varying the dipping time between 0 and 120 s at 773 °C. The microstructure and phase constitution of the reaction layer were investigated by various observational methods. Phase formation is discussed using a phase diagram calculated by Thermo-CalcTM. Under a 30 s hot-dipping process, no reaction occurred due to the formation of a Fe3O4 layer on the steel surface. The Fe3O4 layer decomposed by a reduction reaction with Al-Mn molten alloy, constituent elements of steel dissolved into a liquid, and the reaction-layer nucleus was formed toward the liquid phase. A coated layer consists of a solidified layer of Al and Al6Mn and a reactive layer formed beneath it. The reaction layer is formed mainly by inter-diffusion of Al and Fe in the solid state, which is arranged on the steel in the order of Al11Mn4 → FeAl3 (θ → Fe2Al5 (η phases, and the Fe3AlC (κ in several nm bands formed at the interface between the η-phase and steel.

  13. Corrosion protection of galvanized steels by silane-based treatments

    Science.gov (United States)

    Yuan, Wei

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

  14. Application of artificial neural network and adaptive neuro-fuzzy inference system to investigate corrosion rate of zirconium-based nano-ceramic layer on galvanized steel in 3.5% NaCl solution

    International Nuclear Information System (INIS)

    Mousavifard, S.M.; Attar, M.M.; Ghanbari, A.; Dadgar, M.

    2015-01-01

    Highlights: • Film formation of Zr-based conversion coating under different conditions was investigated. • We study the effect of some parameters on anticorrosion performance of conversion coating. • Optimization of processing conditions for surface treatment of galvanized steel was obtained. • Modeling and predicting corrosion current density of treated surfaces was performed using ANN and ANFIS. - Abstract: A nano-ceramic Zr-based conversion solution was prepared and optimization of Zr concentration, pH, temperature and immersion time for the treatment of hot-dip galvanized steel (HDG) was performed. SEM microscopy was utilized to investigate the microstructure and film formation of the layer and the anticorrosion performance of conversion coating was studied using polarization test. Artificial intelligence systems (ANN and ANFIS) were applied on the data obtained from polarization test and the models for predicting corrosion current density values were attained. The outcome of these models showed proper predictability of the methods. The influence of input parameters was discussed and the optimized conditions for Zr-based conversion layer formation on the galvanized steel were obtained as follows: pH 3.8–4.5, Zr concentration of about 100 ppm, ambient temperature and immersion time of about 90 s

  15. Application of artificial neural network and adaptive neuro-fuzzy inference system to investigate corrosion rate of zirconium-based nano-ceramic layer on galvanized steel in 3.5% NaCl solution

    Energy Technology Data Exchange (ETDEWEB)

    Mousavifard, S.M. [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Attar, M.M., E-mail: attar@aut.ac.ir [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Ghanbari, A. [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Dadgar, M. [Textile Engineering Department, Neyshabur University, Neyshabur (Iran, Islamic Republic of)

    2015-08-05

    Highlights: • Film formation of Zr-based conversion coating under different conditions was investigated. • We study the effect of some parameters on anticorrosion performance of conversion coating. • Optimization of processing conditions for surface treatment of galvanized steel was obtained. • Modeling and predicting corrosion current density of treated surfaces was performed using ANN and ANFIS. - Abstract: A nano-ceramic Zr-based conversion solution was prepared and optimization of Zr concentration, pH, temperature and immersion time for the treatment of hot-dip galvanized steel (HDG) was performed. SEM microscopy was utilized to investigate the microstructure and film formation of the layer and the anticorrosion performance of conversion coating was studied using polarization test. Artificial intelligence systems (ANN and ANFIS) were applied on the data obtained from polarization test and the models for predicting corrosion current density values were attained. The outcome of these models showed proper predictability of the methods. The influence of input parameters was discussed and the optimized conditions for Zr-based conversion layer formation on the galvanized steel were obtained as follows: pH 3.8–4.5, Zr concentration of about 100 ppm, ambient temperature and immersion time of about 90 s.

  16. Heteroepitaxial growth of Fe{sub 2}Al{sub 5} inhibition layer in hot-dip galvanizing of an interstitial-free steel

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Kuang-Kuo [Department of Materials and Optoelectronic Science, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China); Chang, Liuwen, E-mail: lwchang@mail.nsysu.edu.t [Department of Materials and Optoelectronic Science, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China); Gan, Dershin; Wang, Hung-Ping [Department of Materials and Optoelectronic Science, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China)

    2010-02-01

    This work presents characterization results on inhibition layers formed on a TiNb-stabilized interstitial-free steel after short time galvanizing. The Fe-Al and steel interface was free from oxide, so that the Fe-Al intermetallic compound could directly nucleate on ferrite grains. Electron diffraction performed in a transmission electron microscope showed that only Fe{sub 2}Al{sub 5} was formed and it had a well-defined orientation relationship of [110]{sub Fe(sub/2)Al(sub/5)}// [111]{sub Fe}, (001){sub Fe(sub/2)Al(sub/5)}//(011){sub Fe} and (110){sub Fe(sub/2)Al(sub/5)}//(211){sub Fe} with Fe substrate. The structure of the interfaces between Fe{sub 2}Al{sub 5} and Fe is discussed. The epitaxially nucleated Fe{sub 2}Al{sub 5} grains on Fe substrate had very small grain size, 20 nm or less, and several variants were intimately mixed. The grains grew rapidly to hundreds of nanometers toward the Zn side.

  17. Contribution to the study of the influence of zinc bath composition on corrosion resistance of coatings obtained by galvanization

    International Nuclear Information System (INIS)

    Cabrillac, Claude

    1969-01-01

    This research thesis deals with the influence of zinc purity on the corrosion resistance of a coating obtained by galvanization, and on its effect on cathodic protection. This study therefore addresses methods and tests processes (notably salt spray test) aiming at assessing the efficiency of steel protection by hot galvanization, and aims at highlighting the influence of galvanization bath purity or composition on corrosion resistance of galvanized layers

  18. Mathematical approach in galvanized steel sheet coatings

    International Nuclear Information System (INIS)

    Perez, A.; Andres, L.J.; Gonzalez, I.; Fernandez, B.; Puente, J.M.

    1998-01-01

    A short review of the kinetics models for the formation of Fe-Zn alloy phases in the galvannealing process is presented. It will focus on the continuous process which is often used by the automotive industry. A first mathematical approach of the kinetics growth of the δ phase has been done using a continuous hot-dipping process simulator which resembles the conditions of the galvannealing process in production lines. Hold time and the galvannealing temperature as well as the weight of the coating were varied. The preliminary results of the iron content and proportion of δ phase in the coating are in agreement with the results obtained by other authors. (Author) 16 refs

  19. Wear of Shaped Surfaces of PVD Coated Dies for Clinching

    Directory of Open Access Journals (Sweden)

    Miroslav Džupon

    2017-11-01

    Full Text Available A clinching method that uses a simple toolset consisting of a punch and a die, is utilized for joining lightweight materials. This paper is aimed at investigating the wear of the die cavity of a clinching tool. A clinching tool with a specially shaped cavity was used for joining thin hot-dip galvanized steel sheets. Various types of physical vapour deposition (PVD coatings such as ZrN, CrN and TiCN were deposited on the shaped surface of the die using Lateral Rotating Arc-Cathodes technology. Hot-dip galvanized steel sheets were used for testing the clinching tool. The material properties of PVD coatings that were deposited on the shaped part of the clinching die were evaluated. Finite Element Analysis was used to localize the area of the shaped part of the die and the part of surface area of the cylindrical die cavity of ϕ 5.0 mm, in which high contact pressure values were predicted. The prediction of the start of the wear cycle was verified experimentally by the clinching of 300 samples of hot-dip galvanized steel sheets. Unlike the CrN and ZrN coatings, the TiCN coating remained intact on the entire surface of the die.

  20. Evaluation of mechanically treated cerium (IV) oxides as corrosion inhibitors for galvanized steel

    Energy Technology Data Exchange (ETDEWEB)

    Deflorian, F., E-mail: flavio.deflorian@ing.unitn.it [Department of Materials Engineering and Industrial Technology, University of Trento, Via Mesiano 77, 38123 Trento (Italy); Fedel, M.; Rossi, S. [Department of Materials Engineering and Industrial Technology, University of Trento, Via Mesiano 77, 38123 Trento (Italy); Kamarchik, P. [PPG Industries, Coatings Innovation Center, 4325 Rosanna Drive, Allison Park, PA 15101 (United States)

    2011-09-30

    The use of cerium salts as corrosion inhibitors for hot dip galvanized steel has been object of a numerous studies in the last few years. The role of cerium ions as corrosion inhibitors was proved: cerium is able to block the cathodic sites of the metal, forming insoluble hydroxides and oxides on the zinc surface. This fact leads to a dramatic decrease of the cathodic current densities and, therefore, to a reduction the overall corrosion processes. On the other hand, the potential of cerium oxides as corrosion inhibitors was also proposed. However, the real effectiveness of this kind of anticorrosive pigments has not been clarified yet. In this work cerium (IV) oxides are considered as corrosion inhibitors for galvanized steel. The corrosion inhibition mechanism of mechanically treated (milled) CeO{sub 2} alone and in combination with milled SiO{sub 2} nanoparticles was investigated. For this purpose milled CeO{sub 2}, CeO{sub 2} and SiO{sub 2} milled together and milled SiO{sub 2} particles were studied as corrosion inhibitors in water solution. Therefore, the different mechanically treated particles were dispersed in 0.1 M NaCl solution to test their effectiveness as corrosion inhibitors for galvanized steel. The galvanized steel was immersed in the different solutions and the corrosion inhibition efficiency of the different particles was measured by means of electrochemical techniques. For this purpose, electrochemical impedance spectroscopy (EIS) measurements were carried out, monitoring the evolution of the corrosion processes occurring at the metal surface with the immersion time in the solution. The effect of the different pigments was also investigated by carrying out anodic and cathodic polarization measurements. The polarization curves were acquired under conditions of varied pH. The experimental measurements suggest that the mechanical treatment performed on the SiO{sub 2} and CeO{sub 2} particles promote the formation of an effective corrosion pigment

  1. 40 CFR 465.20 - Applicability; description of the galvanized basis material subcategory.

    Science.gov (United States)

    2010-07-01

    ... galvanized basis material subcategory. 465.20 Section 465.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS COIL COATING POINT SOURCE CATEGORY Galvanized Basis Material Subcategory § 465.20 Applicability; description of the galvanized basis material...

  2. Rapid cooling in continuous annealing and galvanizing lines; Refroidissement rapide dans les lignes de recuit continu et de galvanisation

    Energy Technology Data Exchange (ETDEWEB)

    Renard, M. [DREVER International SA, Angleur (Belgium); Gouriet, J.B.; Planquart, Ph.; Van Beeck, J.; Buchlin, J.M. [Von Karman Institute for Fluid Dynamics Brussels (Belgium)

    2003-08-01

    The production of new steel grades - such as dual phase and TRIP steels - requires improvements to both process and equipment of continuous galvanizing lines. In particular, progress has to be obtained in cooling technology in order to get the desired mechanical properties. This paper presents a study of design parameters allowing the optimization of fast gas multi-jet cooling systems. The thermal study involves the application of infrared thermography and three-dimensional numerical simulations. Furthermore, a dynamic study is performed in order to reduce steel strip vibration. (authors)

  3. About the effect of melted zinc mass additives on the formation on layers during hot galvanizing; Zur Wirkung von Zusaetzen zur Zinkschmelze auf die Schichtbildung beim Feuerverzinken

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, P.; Schulz, W.D. [Institut fuer Korrosionsschutz Dresden GmbH, Gostritzer Str. 61-63, D-01217 Dresden (Germany)

    2002-09-01

    The influence of various melted zinc mass additives on the galvanizing behaviour of steels is examined by way of comparison. The mechanisms influencing the formation of layers are very different. In case tin is added, a material barrier of enriched tin develops in the zinc coating, which inhibits the iron transport. The mechanisms of Ni, Ti and Al in the melted zinc mass are explained by means of a new theory on the formation of layers, which is based on the influence of the growth of layers via hydrogen escaping from the steel surface during hot galvanizing. This behaviour makes it clear why the single melted mass additives only have a layer-thickness reducing effect on steels with very definite Si contents. The different inhibitions of the growth of the layer during hot galvanizing are discussed. (Abstract Copyright[2002], Wiley Periodicals, Inc.) [German] Der Einfluss unterschiedlicher Zinkschmelzezusaetze auf das Verzinkungsverhalten der Staehle wird vergleichend untersucht. Die Mechanismen der Einflussnahme auf die Schichtbildung sind sehr unterschiedlich. Bei Zusatz von Zinn entsteht im Zinkueberzug eine Materialbarriere aus angereichertem Zinn, die den Eisentransport hemmt. Die Wirkungsweise von Ni, Ti und Al in der Zinkschmelze wird mit Hilfe einer neuen Theorie der Schichtbildung erklaert. Diese beruht auf der Beeinflussung des Schichtwachstums durch Wasserstoff, der waehrend des Feuerverzinkens aus der Stahloberflaeche austritt. Diese Erklaerung macht verstaendlich, warum die einzelnen Schmelzezusaetze nur bei Staehlen mit ganz bestimmten Si-Gehalten schichtdickenreduzierend wirken. Die unterschiedlichen Hemmungen des Schichtwachstums beim Feuerverzinken werden diskutiert. (Abstract Copyright[2002], Wiley Periodicals, Inc.)

  4. First stages of zinc runoff in humid tropical climate

    International Nuclear Information System (INIS)

    Meraz, E.; Veleva, L.; Acosta, M.

    2007-01-01

    Frequently used metals in building application are Zinc and hot dip galvanized steel. The zinc has a relatively good atmospheric resistance, due to its oxidation in air and formation of protective layer. However, some of the zinc corrosion products can be dissolved by pluvial precipitations and water condensed on the metal surface. This process is called metal runoff. In order to estimate el zinc runoff in humid tropical climate, since its firs stages, samples of pure zinc and hot dip galvanized steel have been exposed during 2 years in outdoor atmosphere (rural and urban). The data reveal high annual values of zinc runoff (8,20-12,40±0.30 g/m''2 ano), being this process 80% of total mass loss of corroded zinc. The runoff and corrosion processes are more accelerated for zinc, than that of galvanized steel. The principal factors that control the runoff process are discussed. (Author) 48 refs

  5. Corrosion and protection of metals in the rural atmosphere of El Pardo Spain (PATINA/CYTED project)

    International Nuclear Information System (INIS)

    Simancas, J.; Castano, J. G.; Morcillo, M.

    2003-01-01

    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), C'' (Zn), Cu (Cu) and C1 (Al). Its average temperature and relative humidity is 13 degree centigrade and 62.8, respectively, and it has low SO 2 and C1''- 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). (Author) 9 refs

  6. Effect of Coating-thickness on the formability of hot dip aluminized steel

    International Nuclear Information System (INIS)

    Awan, G.H.; Ahmed, F.; Hasan, F.

    2008-01-01

    The influence of coating thickness on the formability and ductility of hot-dip-aluminized steel has been determined using a 3-point bend test and optical metallography. The ductility / formability was estimated from the 3-point bend test wherein the angle of bend at which the cracks start to appear on the surface of the aluminized sheet during bending, was taken as an index of the formability / ductility. It was observed that as the amount of silicon in the aluminising melt was gradually increased the measured ductility of the sheet sample also increased. Metallographic examination has shown that as the amount of silicon in the aluminising melt was increased the thickness of the intermediate compound layer, between the outer aluminum coat and the substrate steel, decreased. It was thus indicated from these experiments that the formability / ductility of the sheet was inversely related to the thickness of the interlayer. (author)

  7. Fatigue of coated and laser hardened steels

    International Nuclear Information System (INIS)

    La Cruz, P. de.

    1990-01-01

    In the present work the effect of ion nitriding, laser hardening and hot dip galvanizing upon the fatigue limit and notch sensitivity of a B-Mn Swedish steel SS 2131 have been investigated. The fatigue tests were performed in plane reverse bending fatigue (R=1). The quenched and tempered condition was taken as the reference condition. The microstructure, microhardness, fracture surface and coating appearance of the fatigue surface treated specimens were studied. Residual stress and retained austenite measurements were also carried out. It was found that ion nitriding improves the fatigue limit by 53 % for smooth specimens and by 115 % for notched specimens. Laser hardening improves the fatigue limit by 18 % and 56 % for smooth and notched specimen respectively. Hot dip galvanizing gives a slight deterioration of the fatigue limit (9 % and 10 % for smooth and notched specimen respectively). Ion nitriding and laser hardening decrease the value of the notch sensitivity factor q by 78 % and 65 % respectively. Hot dip galvanizing does not modify it. A simple schematic model based on a residual stress distribution, has been used to explain the different effects. It seems that the presence of the higher compressive residual stresses and the higher uniformity of the microstructure may be the causes of the better fatigue performance of ion nitrided specimens. (119 refs.) (author)

  8. Influence of Experimental Parameters Using the Dip-Coating Method on the Barrier Performance of Hybrid Sol-Gel Coatings in Strong Alkaline Environments

    Directory of Open Access Journals (Sweden)

    Rita B. Figueira

    2015-04-01

    Full Text Available Previous studies have shown that the barrier effect and the performance of organic-inorganic hybrid (OIH sol-gel coatings are highly dependent on the coating deposition method as well as on the processing conditions. However, studies on how the coating deposition method influences the barrier properties in alkaline environments are scarce. The aim of this experimental research was to study the influence of experimental parameters using the dip-coating method on the barrier performance of an OIH sol-gel coating in contact with simulated concrete pore solutions (SCPS. The influence of residence time (Rt, a curing step between each dip step and the number of layers of sol-gel OIH films deposited on hot-dip galvanized steel to prevent corrosion in highly alkaline environments was studied. The barrier performance of these OIH sol-gel coatings, named U(400, was assessed in the first instants of contact with SCPS, using electrochemical impedance spectroscopy and potentiodynamic methods. The durability and stability of the OIH coatings in SCPS was monitored during eight days by macrocell current density. The morphological characterization of the surface was performed by Scanning Electronic Microscopy before and after exposure to SCPS. Glow Discharge Optical Emission Spectroscopy was used to investigate the thickness of the U(400 sol-gel coatings as a function of the number of layers deposited with and without Rt in the coatings thickness.

  9. Effect of Mg content on microstructure and corrosion behavior of hot dipped Zn–Al–Mg coatings

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Caizhen; Lv, Haibing [Research Centre of Laser Fusion, CAEP, P.O.Box 919-988-5, Mianyang, Sichuan 621900 (China); Zhu, Tianping [Department of Chemical and Materials Engineering, The University of Auckland, PB 92019, Auckland 1142 (New Zealand); Zheng, Wanguo [Research Centre of Laser Fusion, CAEP, P.O.Box 919-988-5, Mianyang, Sichuan 621900 (China); Yuan, Xiaodong, E-mail: xdyuan@caep.cn [Research Centre of Laser Fusion, CAEP, P.O.Box 919-988-5, Mianyang, Sichuan 621900 (China); Gao, Wei, E-mail: w.gao@auckland.ac.nz [Department of Chemical and Materials Engineering, The University of Auckland, PB 92019, Auckland 1142 (New Zealand)

    2016-06-15

    In this article, Zn–Al–Mg coatings were prepared by hot dipping method. The surface morphology, cross–section microstructure, microhardness, composition, corrosion behaviour of ZAM coatings were investigated by using X–ray diffraction (XRD), Optical microscope, Environmental scanning electron microscopy equipped with EDS (FESEM–EDS), Microhardness tester and Electrochemical analysis respectively. Corrosion test was also performed in a standard salt fog spray chamber. Microstructure studies indicates that Zn grain size was refined and eutectic areas at Zn grain boundary areas increased with increasing Mg content. ZA5M1.5 and ZA5M2 coatings have two distinct layers. Mg tends to exist in the outer layer while Al is in the inner layer. The inner layer is composed of Al{sub 5}Fe{sub 2}Zn{sub 0.4} intermetallic, which may to contribute to the microhardness. The outer layer is Zn grains surrounded by Zn–Mg etutectics, which may improve the corrosion resistance. The microhardness is more than 700 HV{sub 50g} for Al-rich layer and around 151 HV{sub 25g} for Mg-rich layer. The improved corrosion resistance of Zn–5%Al-1.5%Mg coating comes from the corrosion product of flocculent type simonkolleite, which prolongs the micro-path and impedes the movement of O{sub 2} and H{sub 2}O, ultimately retards the overall corrosion process. - Highlights: • Two-layer structured Zn–Al–Mg coatings were prepared by hot dipping method. • Mg exists in the outer layer while Al exists in the inner layer of Zn–Al–Mg coating. • Zn–Al–Mg coating has better protective ability than Zn and Zn–Al coatings. • The Mg-modified simonkolleite is the reason of the enhanced corrosion resistance.

  10. The mechanical properties and microstructures of vanadium bearing high strength dual phase steels processed with continuous galvanizing line simulations

    Science.gov (United States)

    Gong, Yu

    For galvanized or galvannealed steels to be commercially successful, they must exhibit several attributes: (i) easy and inexpensive processing in the hot mill, cold mill and on the coating line, (ii) high strength with good formability and spot weldability, and (iii) good corrosion resistance. At the beginning of this thesis, compositions with a common base but containing various additions of V or Nb with or without high N were designed and subjected to Gleeble simulations of different galvanizing(GI), galvannealing(GA) and supercooling processing. The results revealed the phase balance was strongly influenced by the different microalloying additions, while the strengths of each phase were somewhat less affected. Our research revealed that the amount of austenite formed during intercritical annealing can be strongly influenced by the annealing temperature and the pre-annealing conditions of the hot band (coiling temperature) and cold band (% cold reduction). In the late part of this thesis, the base composition was a low carbon steel which would exhibit good spot weldability. To this steel were added two levels of Cr and Mo for strengthening the ferrite and increasing the hardenability of intercritically formed austenite. Also, these steels were produced with and without the addition of vanadium in an effort to further increase the strength. Since earlier studies revealed a relationship between the nature of the starting cold rolled microstructure and the response to CGL processing, the variables of hot band coiling temperature and level of cold reduction prior to annealing were also studied. Finally, in an effort to increase strength and ductility of both the final sheet (general formability) and the sheared edges of cold punched holes (local formability), a new thermal path was developed that replaced the conventional GI ferrite-martensite microstructure with a new ferrite-martensite-tempered martensite and retained austenite microstructure. The new

  11. The recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor

    International Nuclear Information System (INIS)

    Ren Xiulian; Wei Qifeng; Hu Surong; Wei Sijie

    2010-01-01

    This paper reports the optimization of the process parameters for recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor. The experiments were carried out in an ammoniacal ammonium chloride system. The influence of composition of electrolytes, pH, stirring rate, current density and temperature, on cathodic current efficiency, specific power consumption and anodic dissolution of Zn were investigated. The results indicate that the cathode current efficiency increases and the hydrogen evolution decreased with increasing the cathode current density. The partial current for electrodeposition of Zn has liner relationship with ω 1/2 (ω: rotation rate). The highest current efficiency for dissolving zinc was obtained when NH 4 Cl concentration was 53.46 g L -1 and the anodic dissolution of zinc was determined by mass transfer rate at stirring rate 0-300 r min -1 . Increase in temperature benefits to improve CE and dissolution of Zn, and reduce cell voltage. Initial pH of electrolytes plays an important role in the deposition and anodic dissolution of Zn. The results of single factor experiment show that about 50% energy consumption was saved for electrodeposition of Zn in the anion-exchange membrane electrolysis reactor.

  12. Formation of microstructural features in hot-dip aluminized AISI 321 stainless steel

    Science.gov (United States)

    Huilgol, Prashant; Rajendra Udupa, K.; Udaya Bhat, K.

    2018-02-01

    Hot-dip aluminizing (HDA) is a proven surface coating technique for improving the oxidation and corrosion resistance of ferrous substrates. Although extensive studies on the HDA of plain carbon steels have been reported, studies on the HDA of stainless steels are limited. Because of the technological importance of stainless steels in high-temperature applications, studies of their microstructural development during HDA are needed. In the present investigation, the HDA of AISI 321 stainless steel was carried out in a pure Al bath. The microstructural features of the coating were studied using scanning electron microscopy and transmission electron microscopy. These studies revealed that the coating consists of two regions: an Al top coat and an aluminide layer at the interface between the steel and Al. The Al top coat was found to consist of intermetallic phases such as Al7Cr and Al3Fe dispersed in an Al matrix. Twinning was observed in both the Al7Cr and the Al3Fe phases. Furthermore, the aluminide layer comprised a mixture of nanocrystalline Fe2Al5, Al7Cr, and Al. Details of the microstructural features are presented, and their formation mechanisms are discussed.

  13. Thermogalvanic corrosion and galvanic effects of copper and AISI 316L stainless steel pairs in heavy LiBr brines under hydrodynamic conditions

    International Nuclear Information System (INIS)

    Sánchez-Tovar, R.; Montañés, M.T.; García-Antón, J.

    2012-01-01

    Highlights: ► Thermogalvanic corrosion results in an increase of the current densities. ► Thermogalvanic effect increases as temperature difference between tubes is higher. ► Potentials fit linearly with increase in temperature. ► ZRA shows hot cathodes for AISI 316L while cold ones for copper and galvanic pairs. ► Weight loss tests show a combined effect between thermogalvanic and galvanic effects. - Abstract: Thermogalvanic corrosion of the copper/copper and AISI 316L/AISI 316L stainless steel pairs was studied in heavy lithium bromide brines under hydrodynamic conditions. The galvanic coupling effect between copper and stainless steel was also analysed. The cold electrode (25 °C) was the stainless steel for the galvanic pair, whereas copper temperature varied (25, 50 and 75 °C). A hydrodynamic circuit was designed to study thermogalvanic corrosion by means of the zero resistance ammeter technique. Hot cathodes take place in stainless steel pairs while cold cathodes are present in copper/copper and stainless steel/copper pairs; this agrees with the thermal temperature coefficient of the potential sign. Thermogalvanic corrosion increases corrosion rates, especially working with copper. Weight loss measurements show that there is a combined effect due to the thermogalvanic and the galvanic effects.

  14. Nicotinic acid as a nontoxic corrosion inhibitor for hot dipped Zn and Zn-Al alloy coatings on steels in diluted hydrochloric acid

    Energy Technology Data Exchange (ETDEWEB)

    Ju Hong [Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Li Yan [Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China)], E-mail: yanlee@ms.qdio.ac.cn

    2007-11-15

    The inhibition effect of nicotinic acid for corrosion of hot dipped Zn and Zn-Al alloy coatings in diluted hydrochloric acid was investigated using quantum chemistry analysis, weight loss test, electrochemical measurement, and scanning electronic microscope (SEM) analysis. Quantum chemistry calculation results showed that nicotinic acid possessed planar structure with a number of active centers, and the populations of the Mulliken charge, the highest occupied molecular orbital (HOMO), and the lowest unoccupied molecular orbital (LUMO) were found mainly focused around oxygen and nitrogen atoms, and the cyclic of the benzene as well. The results of weight loss test and electrochemical measurement indicated that inhibition efficiency (IE%) increased with inhibitor concentration, and the highest inhibition efficiency was up to 96.7%. The corrosion inhibition of these coatings was discussed in terms of blocking the electrode reaction by adsorption of the molecules at the active centers on the electrode surface. It was found that the adsorption of nicotinic acid on coating surface followed Langmuir adsorption isotherm with single molecular layer, and nicotinic acid adsorbed on the coating surface probably by chemisorption. Nicotinic acid, therefore, can act as a good nontoxic corrosion inhibitor for hot dipped Zn and Zn-Al alloy coatings in diluted hydrochloric acid solution.

  15. EFFECT OF DEW POINT OF ATMOSPHERE OF CGL’S ANNEALING FURNACES ON THE QUALITY OF GA COATING ON BAKE HARDENABLE STEEL

    Directory of Open Access Journals (Sweden)

    Juliana Porto Guimarães

    2013-10-01

    Full Text Available The strip steel surface condition after continuous annealing of strip is extremely important to the quality of galvannealed coating (GA. The presence of oxides or precipitated can affect the reactions at the coating/substrate interface and decrease the zinc wettability on the steel surface, leading to various defects in the final product. To avoid oxidation of the material during continuous annealing, a protective atmosphere is used in the furnaces. Despite this atmosphere, it is possible the selective oxidation or precipitation of second phase particles, being the dew point of atmosphere one of the leading factors to reduce this occurrence. This study aims to evaluate the effect of the dew point on the quality of GA coatings applied to a bake hardenable steel. The continuous annealing under dew points of –60°C, 30°C and 0°C, as well as hot dip galvanizing, were performed in a Hot Dip Process Simulator. It is found that the dew point has a decisive influence on the amount, distribution and type of oxides formed, and the condition of –30°C provided the coating with less failures and better adhesion.

  16. Interface fracture behavior of zinc coatings on steel : Experiments and finite element calculations

    NARCIS (Netherlands)

    Song, G.M.; Sloof, W.G.; Pei, Y.T.; de Hosson, J.T.M.

    2006-01-01

    Hot-dipped galvanized steels are widely used in the automotive industry. The formability and damage resistance of zinc coatings depend strongly on their microstructure and adhesion to the steel substrate. In order to improve the mechanical performance of zinc coatings, the influence of their

  17. Development of Zn-Al-Cu coatings by hot dip coated technology: preparation and characterization

    International Nuclear Information System (INIS)

    Cervantes, J.; Barba, A.; Hernandez, M. A.; Salas, J.; Espinoza, J. L.; Denova, C.; Torres-Villasenor, G.; Conde, A.; Covelo, A.; Valdez, R.

    2013-01-01

    In the present study, research concerning Zn-Al-Cu coatings on low carbon steels has been conducted in order to characterize different properties obtained by a hot-dip coated process. The results include preparation procedure as well as the processing parameters of the coatings. The obtained coatings were subjected to a cold rolling process followed by an anneal heat treatment at different temperatures and under different time conditions. The structural characteristics of coatings have been investigated by optical and electron microscopy. The mechanical properties were obtained by using micro-hardness testing, deep drawing and wear tests whereas chemical analyses were carried out using the SEM/EDAX microprobe. The corrosion properties were achieved by using a salt spray fog chamber and potentiodynamic tests in a saline solution. The coatings are resistant to corrosion and wear in the presence of sodium chloride, therefore, the coatings could be an attractive alternative for application in coastal areas, and adequate wear adhesive resistance. (Author)

  18. Hot-Dip Aluminizing on AISI F55–UNS S32760 Super Duplex Stainless Steel Properties: Effect of Thermal Treatments

    Directory of Open Access Journals (Sweden)

    Andrea Francesco Ciuffini

    2017-11-01

    Full Text Available The behavior of super duplex stainless steels AISI F55-UNS S32760 in hot-dip aluminizing process has been studied, investigating the influence of cold working and of different initial microstructures obtained through a preliminary thermal treatment. The microstructural features examined are the secondary austenite precipitation, the static recovery of ferrite and the thermal dissolution of austenite within ferritic matrix. The hot-dip aluminizing temperature has been optimized through sessile drop tests. The treatment has been performed at 1100 °C for 300 s, 900 s and 2700 s. A strong chemical interaction occurs, generating intermetallic compounds at the interface. Molten aluminum interacts exclusively with the ferritic phase due to its much higher diffusivity in this phase coupled with its marked ferrite-stabilizer behavior. Thus, the influence of cold working is not remarkable, since the strains are mainly allocated by austenitic phase. The diffusivity of aluminum increases due to lattice defects thermally generated and, mainly, to influence given by grain boundaries, multiplied by secondary austenite precipitation, which act as short-circuit diffusion paths. Ni and Cr contents in the ferritic matrix have an influence but not highly relevant. Then, the best starting condition of the super duplex stainless steel substrates, to obtain a thick interfacial layer, are the thermal annealing at 1080 °C for 360 s/mm after a solution thermal treatment at 1300 °C for 60 s/mm.

  19. Numerical analysis of fluid flow and heat transfer in molten zinc pot of continuous hot-dip galvanizing line

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y.H.

    2000-07-01

    A numerical model adopting a partially staggered grid system for the location of dependent variables has been developed to analyze the fluid flow and temperature distributions in a molten zinc pot of No. 2 CGL of POSCO K wangyang strip mills. A control volume based finite difference procedure was employed to solve the conservation equations transformed by using the boundary-fitted-coordinate (BFC) system. The calculation results have shown that a change in the steel strip velocity has little influence on the overall flow pattern developed in the pot. The overall temperature distribution was rather uniform as predicted. However, charging cold ingots directly into the pot produced a non-uniform distribution of temperature. The local temperature fluctuations will promote the formation of intermetallic dross particles. It has been proposed that the non-uniform distribution of temperature could be reduced by selecting an appropriate channel inductor position as well as by optimizing the zinc ingot loading position. (author)

  20. The recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ren Xiulian [College of Ocean, Harbin Institute of Technology at Weihai, Weihai 264209 (China); Wei Qifeng, E-mail: weiqifeng163@163.com [College of Ocean, Harbin Institute of Technology at Weihai, Weihai 264209 (China); Hu Surong; Wei Sijie [College of Ocean, Harbin Institute of Technology at Weihai, Weihai 264209 (China)

    2010-09-15

    This paper reports the optimization of the process parameters for recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor. The experiments were carried out in an ammoniacal ammonium chloride system. The influence of composition of electrolytes, pH, stirring rate, current density and temperature, on cathodic current efficiency, specific power consumption and anodic dissolution of Zn were investigated. The results indicate that the cathode current efficiency increases and the hydrogen evolution decreased with increasing the cathode current density. The partial current for electrodeposition of Zn has liner relationship with {omega}{sup 1/2} ({omega}: rotation rate). The highest current efficiency for dissolving zinc was obtained when NH{sub 4}Cl concentration was 53.46 g L{sup -1} and the anodic dissolution of zinc was determined by mass transfer rate at stirring rate 0-300 r min{sup -1}. Increase in temperature benefits to improve CE and dissolution of Zn, and reduce cell voltage. Initial pH of electrolytes plays an important role in the deposition and anodic dissolution of Zn. The results of single factor experiment show that about 50% energy consumption was saved for electrodeposition of Zn in the anion-exchange membrane electrolysis reactor.

  1. The recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor.

    Science.gov (United States)

    Ren, Xiulian; Wei, Qifeng; Hu, Surong; Wei, Sijie

    2010-09-15

    This paper reports the optimization of the process parameters for recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor. The experiments were carried out in an ammoniacal ammonium chloride system. The influence of composition of electrolytes, pH, stirring rate, current density and temperature, on cathodic current efficiency, specific power consumption and anodic dissolution of Zn were investigated. The results indicate that the cathode current efficiency increases and the hydrogen evolution decreased with increasing the cathode current density. The partial current for electrodeposition of Zn has liner relationship with omega(1/2) (omega: rotation rate). The highest current efficiency for dissolving zinc was obtained when NH(4)Cl concentration was 53.46 g L(-1) and the anodic dissolution of zinc was determined by mass transfer rate at stirring rate 0-300 r min(-1). Increase in temperature benefits to improve CE and dissolution of Zn, and reduce cell voltage. Initial pH of electrolytes plays an important role in the deposition and anodic dissolution of Zn. The results of single factor experiment show that about 50% energy consumption was saved for electrodeposition of Zn in the anion-exchange membrane electrolysis reactor. Copyright 2010 Elsevier B.V. All rights reserved.

  2. Reduce of adherence problems in galvanised processes through data mining techniques; Reducciond e problemas de adherencia en procesos de galvanizado mediante tecnicas de mineria de datos

    Energy Technology Data Exchange (ETDEWEB)

    Martinez de Pison, F. J.; Ordieres, J.; Pernia, A.; Alba, F.; Torre, V.

    2007-07-01

    This paper presents an example of the application of data mining techniques to obtain hidden knowledge from the historical data of a hot dip galvanizing process and to establish rules to improve quality in the final product and to reduce errors in the process. For this purpose, the tuning records of a hot dip galvanizing line where coils with adherence problems in the zinc coating had been identified were used as starting point. From the database of the process, the classical data mining approach was applied to obtain and analyze a number of decision trees hat classified two types of coils, i.e. those with the right adherence and those with irregular adherence. The variables and values that might have influenced the quality of the coating were extracted from these tress. Several rules that may be applied to reduce the number of faulty coils with adherence problems were also established. (Author) 24 refs.

  3. Reduce of adherence problems in galvanised processes through data mining techniques

    International Nuclear Information System (INIS)

    Martinez de Pison, F. J.; Ordieres, J.; Pernia, A.; Alba, F.; Torre, V.

    2007-01-01

    This paper presents an example of the application of data mining techniques to obtain hidden knowledge from the historical data of a hot dip galvanizing process and to establish rules to improve quality in the final product and to reduce errors in the process. For this purpose, the tuning records of a hot dip galvanizing line where coils with adherence problems in the zinc coating had been identified were used as starting point. From the database of the process, the classical data mining approach was applied to obtain and analyze a number of decision trees hat classified two types of coils, i.e. those with the right adherence and those with irregular adherence. The variables and values that might have influenced the quality of the coating were extracted from these tress. Several rules that may be applied to reduce the number of faulty coils with adherence problems were also established. (Author) 24 refs

  4. Issues in recycling galvanized scrap

    Energy Technology Data Exchange (ETDEWEB)

    Koros, P.J. [LTV Steel Co., Inc., Cleveland, OH (United States); Hellickson, D.A. [General Motors Corp., Detroit, MI (United States); Dudek, F.J. [Argonne National Lab., IL (United States)

    1995-02-10

    The quality of the steel used for most galvanizing (and tinplate) applications makes scrap derived from their production and use a premier solid charge material for steelmaking. In 1989 the AISI created a Task Force to define the issues and to recommend technologically and economically sound approaches to assure continued, unhindered recyclability of the growing volume of galvanized scrap. The AISI program addressed the treatment of full-sized industrial bales of scrap. The current, on-going MRI (US)--Argonne National Laboratory program is focused on ``loose`` scrap from industrial and post-consumer sources. Results from these programs, issues of scrap management from source to steel melting, the choices for handling zinc in iron and steelmaking and the benefits/costs for removal of zinc (and lead) from scrap prior to melting in BOF and foundry operations are reviewed in this paper.

  5. Hot Ductility Behavior of a Peritectic Steel during Continuous Casting

    OpenAIRE

    Arıkan, Mustafa

    2015-01-01

    Hot ductility properties of a peritectic steel for welded gas cylinders during continuous casting were studied by performing hot tensile tests at certain temperatures ranging from 1200 to 700 °C for some cooling rates by using Gleeble-3500 thermo-mechanical test and simulation machine in this study. The effects of cooling rate and strain rate on hot ductility were investigated and continuous casting process map (time-temperature-ductility) were plotted for this material. Reduction of area ...

  6. Review of Thermal Spray Coating Applications in the Steel Industry: Part 2—Zinc Pot Hardware in the Continuous Galvanizing Line

    Science.gov (United States)

    Matthews, S.; James, B.

    2010-12-01

    This two-part article series reviews the application of thermal spray coating technology in the production of steel and steel sheet products. Part 2 of this article series is dedicated to coating solutions in the continuous galvanizing line. The corrosion mechanisms of Fe- and Co-based bulk materials are briefly reviewed as a basis for the development of thermal spray coating solutions. WC-Co thermal spray coatings are commonly applied to low Al-content galvanizing hardware due to their superior corrosion resistance compared to Fe and Co alloys. The effect of phase degradation, carbon content, and WC grain size are discussed. At high Al concentrations, the properties of WC-Co coatings degrade significantly, leading to the application of oxide-based coatings and corrosion-resistant boride containing coatings. The latest results of testing are summarized, highlighting the critical coating parameters.

  7. DEPOSITION OF NICKEL ON CARBON FIBRES BY GALVANIC METHOD

    Directory of Open Access Journals (Sweden)

    Pavol Štefánik

    2012-01-01

    Full Text Available The investigation of coating parameters in quasi-static coating of Ni layer on carbon fibre tow by galvanic method is presented. The tow of fibres was immersed in typical galvanic bath based on NiSO4, NiCl2, Na2SO4 and H3BO3 and current to carbon fibres was supplied by two leading metal rolls which are parts of continuous coating apparatus. The main parameters were current of 1 A, electrolyte temperature of 50 °C and the distance from power contacts to level of galvanic bath (8 or 13 cm. The amount and structure of deposited Ni layer at coating time 15 and 90 seconds of exposure in electrolyte and depth of immersion of tow into bath were discussed.

  8. Corrosion resistance of zinc-based systems in NaCl environment

    Directory of Open Access Journals (Sweden)

    Jiří Votava

    2013-01-01

    Full Text Available Metal components in engineering, industry and agriculture are subjects of degradation process influenced by corrosion which result in changes of mechanical characteristics. The current trend of anticorrosion protection is aimed at inorganic metal zinc-based coatings, such as zinc dipping which can be improved by duplex protection. This paper deals with two types of corrosion protection of steel components by zinc coating, first of which is produced by hot dip galvanizing, the other by Zn-Al spray. Hot dip galvanizing was processed in working conditions; the Zn-Al coating was sprayed following the instructions of producer. It is a special aerosol with particles of Zn and Al sized approximately 5 µm. There have been processed the following tests: analysis of element structure, test of corrosion resistance in aggressive environment of salt spray according to ČSN ISO 9227, further measurement weight of applied coatings according to ČSN EN ISO 3892 and measurement of thickness of passivating coating. There was also made an analysis of coating tenacity on bending pin according to ČSN EN ISO 8401. Quality of applied coatings was evaluated following the metallographic scratch pattern.

  9. 76 FR 23279 - Certain Steel Nails From the People's Republic of China: Amended Final Results of the First...

    Science.gov (United States)

    2011-04-26

    ... vinyl, zinc (galvanized, whether by electroplating or hot-dipping one or more times), phosphate cement... merchandise during the period of review for which the importer-specific assessment rate is zero or de minimis... original investigation, to the day prior to the U.S. International Trade Commission's final determination...

  10. Influence of increasing phosphate/silikate contents on the pitting and general corrosion of galvanized steel tubing and the corrosion of copper in warm water mixed installation systems

    International Nuclear Information System (INIS)

    Ehreke, J.; Stichel, W.

    1989-01-01

    In hot tap water (65 0 C) the influence of a mixture of phosphate/silicate inhibitor on the general, the pitting and the galvanic corrosion of galvanized steel tubes and the general corrosion of copper in mixed installations of both metals was investigated. Increasing concentration of inhibitors descreases the general corrosion rate of galvanized steel and copper. A worth mentioning reduction of pitting and galvanic corrosion of steel could be reached only with high concentrations of 5 mg/l P 2 O 5 and 30 mg/l SiO 2 . Galvannealed tubes are much more sensitive to pitting corrosion than galvanized ones. Referring to this they could not be inhibited. (orig.) [de

  11. Development of Alloy Coating Process of Steel Pipe for Seawater service

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jong Man; Kwon, Taeg Kyu; Lee, Sang Hyeog [Daewoo Shipbuilding and Marine Engineering Co., Ltd., Okpo (Korea)

    2001-02-01

    The new alloy coating process was developed to apply steel pipe for seawater service. This process consists of Zn-Al hot-dip coating treatment immediately following after normal galvanizing treatment. The alloy coating process formed double layer after surface treatment, and the surface layer was similar to that of Galfan steel and the intermetallic layer was also similar to that of aluminized steel. The alloy coating layer protect steel pipe galvanically and provide steel pipe with high resistance to general corrosion of seawater. This new alloy coated steel pipe had also good weldability and adhesion strength of paints compared to galvanized steel. 5 refs., 14 figs.

  12. 46 CFR 160.041-3 - Construction and workmanship.

    Science.gov (United States)

    2010-10-01

    ... construction, with the body, handle, and all fittings of a corrosion-resistant material or suitably protected against corrosion. All ferrous metal employed shall be protected by hot dip galvanizing, or other equally... and joints shall be welded or brazed. Either the body or the cover shall contain a gasket of molded...

  13. Bulletin of Materials Science | News

    Indian Academy of Sciences (India)

    Effects and mechanisms of grain refinement in aluminium alloys ... Corrosion behaviour of hot dip zinc and zinc-aluminium coatings on steel in ... The decrease in tensile strength suggested that galvanized and Zn–55Al–Si coated steel ... Low temperature sintering of MgCuZn ferrite and its electrical and magnetic properties.

  14. Thickness measurement of Sn-Ag hot dip coatings on Large Hadron Collider Superconducting strands by coulometry

    CERN Document Server

    Arnau-Izquierdo, G; Oberli, L R; Scheuerlein, C; Taborelli, M; 10.1149/1.1715094

    2004-01-01

    Amperostatic coulometry is applied for the thickness measurement of Sn-Ag hot dip coatings, which comprise an extended Sn-Cu interdiffusion layer. Complementary measurements, notably weight loss, X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), X-ray fluorescence (XRF) and dynamic secondary ion mass spectroscopy (DSIMS) have been performed in order to obtain a better interpretation of the coulometry results. Based on the experimental results presented in this article the three potential changes that are observed during coulometry measurements are ascribed to (1) the entire dissolution of pure Sn, (2) the formation of a CuCl salt layer and (3) the surface passivation. The measurement of the pure Sn mass is well reproducible despite of strong coating thickness variations that are detected by XRF. Several experimental problems, in particular a coating undercutting, hamper the determination of the Sn mass in the intermetallic Sn-Cu layer.

  15. NAVFAC Ocean Thermal Energy Conversion (OTEC) Project; OTEC Technology Development Report

    Science.gov (United States)

    2010-11-01

    INSIDE FACE OF THE PLATE MUST BE SMOOTH AND FREE FROM WELD SLAG . 9255 WELLINGTON ROAD MANASSAS, VA 20110-4121LOCKHEED MARTIN NAVAL FACILITIES...document by their basic designation number shown below: A. A36 Structural Steel American Society for Testing and Materials (ASTM): A123 Zinc (Hot...Galvanized) Coatings on Iron and Steel Products A153 Zinc Coating (Hot Dip) On Iron and Steel Hardware A307 Specification for Carbon Steel Bolts and

  16. The Effect of Ductile Cast Iron Matrix on Zinc Coating During Hot Dip Galvanising of Castings

    Directory of Open Access Journals (Sweden)

    D. Kopyciński

    2012-12-01

    Full Text Available The growth kinetics of the zinc coating formed on the surface of casting made from ductile iron grade EN-GJS-500-3 was investigated. To produce homogenous metal matrix in test samples, the normalising and ferritising annealing was carried out. Studies showeda heterogeneous structure of cast iron with varying content of the phases formed. This was followed by hot dip galvanising treatment at450°C to capture the growth kinetics of the zinc coating (the time of the treatment ranged from 60 to 600 seconds. Nonlinear estimation of the determined growth kinetics of the alloyed layer of a zinc coating was made and an equation of the zinc coating growth was derived.Based on the results of the investigations it was concluded that thickness of the zinc coating formed on the surface of casting with a 100% pearlitic matrix makes 55% of the thickness of coating formed on the surface in 100% ferritic.

  17. The Effect of Ductile Cast Iron Matrix on Zinc Coating During Hot Dip Galvanising of Castings

    Directory of Open Access Journals (Sweden)

    Kopyciński D.

    2012-12-01

    Full Text Available The growth kinetics of the zinc coating formed on the surface of casting made from ductile iron grade EN-GJS-500-3 was investigated. To produce homogenous metal matrix in test samples, the normalising and ferritising annealing was carried out. Studies showed a heterogeneous structure of cast iron with varying content of the phases formed. This was followed by hot dip galvanising treatment at 450°C to capture the growth kinetics of the zinc coating (the time of the treatment ranged from 60 to 600 seconds. Nonlinear estimation of the determined growth kinetics of the alloyed layer of a zinc coating was made and an equation of the zinc coating growth was derived. Based on the results of the investigations it was concluded that thickness of the zinc coating formed on the surface of casting with a 100% pearlitic matrix makes 55% of the thickness of coating formed on the surface in 100% ferritic.

  18. THE EFFECT OF DEGREASING ON ADHESIVE JOINT STRENGTH

    Directory of Open Access Journals (Sweden)

    Anna Rudawska

    2017-03-01

    Full Text Available The paper investigates the effect of degreasing, a surface preparation methods in adhesive bonding, on adhesive joint strength. 5 types of degreasing agents were used in the study: acetone, extraction naphtha, Ultramyt, Wiko and Loctite 7061. The degreasing operation was performed by three methods: rubbing, spraying and immersion. Strength tests were performed on single-lap adhesive joints of hot-dip galvanized metal sheets made with Loctite 9466 adhesive according to the above variants of surface preparation. The experimental results demonstrate that adhesive joint strength is significantly affected by the applied degreasing agent. Moreover, the method of application of the degreasing agent is crucial, too. The results of strength testing reveal that the most effective degreasing method for hot-dip galvanized metal sheet adhesive joints is spraying using extraction naphtha. Thereby degreased samples have the highest immediate strength and shear strength. The use of extraction naph-tha is also effective in combination with degreasing by rubbing; however, it is not effective when used in combi-nation with immersion, as reflected in the lowest strength results.

  19. Introducing of chrome less protection technology for hot dip galvanized and plasticised sheet in cold mill A.D. plant mill in Skopje

    International Nuclear Information System (INIS)

    Panovska, Liljana; Arsovski, Angel; Sekuloski, Predrag

    2003-01-01

    From the experiences of many well known companies, but also having in mind the legislative of the European Union about the direction which will take in the future and using our own experiences we have come to a conclusion that the process of substitution compounds in which the chromium is found in a shape of its hexavalent ion, as an imperative, as for better environmental protection, so far accomplishing economic effects, and improvement of the products. In other words, we have in plan to make changes in the existing technology for passivation of the galvanized coils and the preparation of the pre-painted coils before the process of applying primer, by ejecting chromate compounds in which chromium is hexavalent and its substitution with non-harmful compounds. Also we predict substitution of the standard chromate primer with universal chromate-free primer. There are planned laboratory experiments in some of the institutes of the companies, which manufacture chemical products of this type (Henkel, BASF, Akzo Nobel and others) as well as semi-industrial and industrial trials at our plant. In the frame of this project the focus will be in a direction of inventing pigments that do not contain strontium chromate that will provide best correlative characteristics in a function of the quality of the pre-painted product. Introducing a green label on the products will mean direct ecological influences (no need of an expensive procedures for reduction and refining) on the environment. Putting out of use the means, which contain hexavalent chromium gives benefits in the possibility of finding sophisticated buyers (manufactures of house-holding products and their decoration) as well as more aggressive marketing appearance on the West European market. (Original)

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

    Science.gov (United States)

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

    2010-01-01

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

  1. Sn and Ti influences on intermetallic phases damage in hot dip galvanizing

    Directory of Open Access Journals (Sweden)

    V. Di Cocco

    2012-10-01

    Full Text Available Protection against metallic materials corrosion is one of the most important means to reduce both maintenance costs and environmental impact. In the last years new studies on chemical baths compositions and fluxes have been performed in order to improve processes, corrosion resistance and mechanical behavior of Zn based coatings. Chemical bath composition is often improved by the Sn addition which increases the fluidity of the melt. Ti addition makes the coatings to change color under appropriate heat treatment. In this work a comparative microstructural analysis, in Zn-Sn and Zn-Ti coatings, is performed to evaluate intermetallic phases formation kinetics and the influence of intermetallic microstructure on coating damage under constant bending deformation.

  2. Characterization of surface defects in high strength galvannealed steels; Charakterisierung der Oberflaechendefekte in hochfesten, nach dem Verzinken waermebehandelten Staehlen

    Energy Technology Data Exchange (ETDEWEB)

    Hong, M.H. [Automotive Steels Research Center, Technical Research Labs., POSCO, Gwangyang (Korea)

    2004-03-01

    Hot-dip galvannealed steel sheets, in which Fe of the substrate steel diffused into upper coating layer so as to be alloyed with Zn through a galvannealing above 450 C followed by hot-dip galvanizing process, generally show superior corrosion resistance, weldability and paintability. They have been widely used in automobile, construction, appliance industries and others. In particular, many researches have been carrying out to produce defect-free coating for an exposed automotive body panel. In the present study, high strength interstitial-free steel sheets containing Mn and P were galvannealed in an industrial continuous galvanizing line and defects on the coating surface were investigated by optical microscopy, scanning electron microscopy and transmission electron microscopy. It is clear that the quality of the substrate strongly affects galvannealed coating and it is essential to keep clean surface just before immediately dipping into molten Zn pot. (orig.) [German] Feuerverzinkte und danach waermebehandelte Stahlbleche, wo Fe aus dem Substratstahl in die obere Beschichtungsschicht diffundiert wie bei Legieren mit Zn und einer Waermebehandlung von ueber 450 C, gefolgt von einem Feuerverzinkverfahren, zeigen im Allgemeinen hervorragende Korrosionsbestaendigkeit, Schweissbarkeit und Anstreichbarkeit. Sie finden ein breites Einsatzgebiet bei Automobilen, im Bauwesen, in Werkzeugindustrien und anderen. Insbesondere wurde von vielen Forschern versucht, eine fehlerfreie Beschichtung fuer ein ungeschuetztes Karosserieteil herzustellen. In der vorliegenden Arbeit wurden hochfeste porenfreie Stahlbleche mit Mn- und P-Gehalt nach dem Verzinken in einer industriellen Endlos-Verzinkungslinie (CGL) waermebehandelt, wobei die Defekte auf der Schichtoberflaeche lichtmikroskopisch, rasterund transmissionselektronenmikroskopisch untersucht wurden. Klar ist, dass die Qualitaet des Substrats die nach dem Verzinken waermebehandelten Schichten beeinflusst und es ist von grosser

  3. Accelerated atmospheric corrosion testing using a cyclic wet/dry exposure test

    International Nuclear Information System (INIS)

    Lyon, S.B.; Thompson, G.E.; Johnson, J.E.; Wood, G.C.

    1989-01-01

    Aluminum corrosion is important in overhead electrical conductors constructed from aluminum wire centrally reinforced by galvanized steel strands. Inspection of conductor after long service has implicated rubber bushing material, on the outside, and the galvanized strands, on the inside, as providing potential galvanic sites for the initiation of rapid aluminum corrosion. Therefore, the galvanic corrosion of aluminum in contact with graphite-loaded neoprene rubber, hot-dip galvanized steel and steel was assessed in a cyclic wet/dry exposure test using mixed-salts spray solutions containing appropriate ratios of sulfate and chloride ion. Aluminum was found to corrode at between 3 to 6 times its uncoupled rate when associated with the rubber material. While the eta-phase, relatively pure Zn, galvanized layer remained intact, galvanic corrosion of aluminum was slow. However, on exposure of the zeta-phase, Zn/Fe intermetallic layer, aluminum corroded about 35 times faster than expected in a solution with a high level of Cl - ion. The importance of these data to conductor lifetime is discussed

  4. Imposed currents in galvanic cells

    NARCIS (Netherlands)

    Biesheuvel, P.M.; Soestbergen, M.; Bazant, M.Z.

    2009-01-01

    We analyze the steady-state behavior of a general mathematical model for reversible galvanic cells, such as redox flow cells, reversible solid oxide fuel cells, and rechargeable batteries. We consider not only operation in the galvanic discharging mode, spontaneously generating a positive current

  5. Galvanic corrosion -- Effect of environmental and experimental variables

    International Nuclear Information System (INIS)

    Roy, A.K.; Fleming, D.L.; Lum, B.Y.

    1999-01-01

    Galvanic corrosion behavior of A 516 steel (UNS K01800) coupled to UNS N06022 and UNS R53400, respectively was evaluated in an acidic brine (pH ∼ 2.75) at 30 C, 60 C and 80 C using zero resistance ammeter method. A limited number of experiments were also performed in a neutral brine involving A 516 steel/UNS N06022 couple. The steady-state galvanic current and galvanic potential were measured as functions of anode-to-cathode (A/C) area ratio and electrode distance. Results indicate that the galvanic current was gradually reduced as the A/C area ratio was increased. No systematic trend on the effect of A/C area ratio on the galvanic potential was observed. Also, no significant effect of electrode distance on the galvanic current and galvanic potential was evident. In general, increased galvanic current was noticed with increasing temperature. The limited data obtained in the neutral brine indicate that the galvanic current was reduced in this environment compared to that in the acidic brine. Optical microscopic examination was performed on all tested specimens to evaluate the extent of surface damage resulting from galvanic interaction. A 516 steel suffered from general corrosion and crevice corrosion in all environments tested. Very light crevice corrosion mark was observed with UNS N06022 and R53400 in the acidic brine at 60 C and 80 C. However, this mark appears to be a surface discoloration and no actual crevice was detected

  6. Evaluation of surface characteristics under fretting of electrical contacts: Removal behaviour of hot dipped tin coating

    International Nuclear Information System (INIS)

    Park, Young Woo; Ramesh Bapu, G.N.K.; Lee, Kang Yong

    2009-01-01

    The fretting corrosion behaviour of hot dipped tin coating is investigated at low fretting cycles at ±25 μm displacement amplitude, 0.5N normal load, 3 Hz frequency, 45-50% relative humidity, and 25 ± 1 deg. C temperature. The typical characteristics of the change in contact resistance with fretting cycles are explained. The fretted surface is examined using laser scanning microscope, scanning electron microscope and energy dispersive X-ray analysis to assess the surface profile, extent of fretting damage, extent of oxidation and elemental distribution across the contact zone. The interdependence of extent of wear and oxidation increases the complexity of the fretting corrosion behaviour of tin coating. The variation of contact resistance clearly revealed the fretting of tin coating from 50 to 1200 cycles and the fretting of the substrate above 1200 cycles. The observed low and stable contact resistance region and the fluctuating resistance region at various fretting cycles are explained and substantiated with Scanning electron microscopy (SEM), laser scanning microscope (LSM) and energy dispersive analysis of X-rays (EDAX) analysis results of the fretted surface.

  7. Hot Ductility Behavior of a Peritectic Steel during Continuous Casting

    Directory of Open Access Journals (Sweden)

    Mustafa Merih Arıkan

    2015-06-01

    Full Text Available Hot ductility properties of a peritectic steel for welded gas cylinders during continuous casting were studied by performing hot tensile tests at certain temperatures ranging from 1200 to 700 °C for some cooling rates by using Gleeble-3500 thermo-mechanical test and simulation machine in this study. The effects of cooling rate and strain rate on hot ductility were investigated and continuous casting process map (time-temperature-ductility were plotted for this material. Reduction of area (RA decreases and cracking susceptibility increases during cooling from solidification between certain temperatures depending on the cooling rate. Although the temperatures which fracture behavior change upon cooling during continuous casting may vary for different materials, it was found that the type of fracture was ductile at 1100 and 1050 °C; semi-ductile at 1000 °C, and brittle at 800 °C for the steel P245NB. There is a ductility trough between 1000 and 725 °C. The ductility trough gets slightly narrower as the cooling rate decreases.

  8. Prediction of hot-ductility of steels during continuous casting using artificial neural networks

    International Nuclear Information System (INIS)

    Liu, W.J.; Emadi, D.; Essadiqi, E.

    2000-01-01

    During continuous casting, transversal cracks can be developed due to tensile stress in temperature regions where the steel exhibits a low ductility. The cracking tendency during continuous casting depends on the steel chemistry and the casting parameters such as lubrication, mold type, secondary cooling and bending/unbending temperatures. To prevent cracking one needs to predict the hot-ductility of a material under continuous-casting conditions. However, hot-ductility is one of the poorly understood material behaviors and cannot be readily modeled using conventional techniques. In the present study, we used an alternative method, namely Artificial Neural Networks (ANN), to model the ductility of a steel under continuous casting conditions. A hot-ductility database was established based on published literature. Several standard three-layer ANN models were then trained using data randomly selected from the database. The outputs of the ANN models were subsequently compared with the remaining data in the database. The results indicate that ANN is a suitable modelling technique for hot-ductility prediction. (author)

  9. Selective surface oxidation and segregation upon short term annealing of model alloys and industrial steel grades

    Energy Technology Data Exchange (ETDEWEB)

    Swaminathan, S.

    2007-07-01

    Segregation and selective oxidation phenomena of minor alloying elements during annealing of steel sheets lead to the formation of bare spots after hot-dip galvanizing. This thesis highlights the influence of annealing conditions and the effect of alloying elements on the selective oxidation in model alloys and some industrial steel grades. Model alloys of binary (Fe-2Si, Fe-2Mn, Fe-0.8Cr), ternary (Fe-2Mn-2Si, Fe-2Mn-0.8Cr, Fe-1Mn-0.8Cr, Fe-1Si-0.8Cr, Fe-2Si-0.8Cr) and quarternary (Fe-2Mn-2Si-0.8Cr) systems were studied. In the case of steels, standard grade interstitial free (IF) steels and experimental grade tensile strength 1000 MPa steel were investigated. All specimens were annealed at 820 C in N{sub 2}-5%H{sub 2} gas atmospheres with the wide range of dew points (i.e. -80 to 0 C). The surface chemistry after annealing and its wettability with liquid Zn have been correlated as a function of dew points by simulating the hot-dip galvanizing process at laboratory scale. (orig.)

  10. Advanced cold rolled steels for automotive applications

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, H. [ThyssenKrupp Steel AG, Eberhardstrasse 12, 44145 Dortmund (Germany); Mattissen, D.; Schaumann, T.W. [ThyssenKrupp Steel AG, Duisburg (Germany)

    2006-09-15

    Advanced multiphase steels offer a great potential for bodies-in-white through their combination of formability and achievable component strength levels. They are first choice for strength and crash-relevant parts of challenging geometry. The intensive development of high-strength multiphase steels by ThyssenKrupp has led to hot dip galvanizing concepts with an outstanding forming potential. Hot rolled, hot dip galvanized complex phase steels are currently produced in addition to cold rolled DP and RA steels. New continuously annealed grades with tensile strength levels of up to 1000 MPa in combination with sufficient ductility for applications mainly in the field of structural automobile elements make use of the classic advantages of microalloying as well as the principles of DP and TRIP steels. Further improvement of properties will be reached by the new class of high manganese alloyed steels. (Abstract Copyright [2006], Wiley Periodicals, Inc.) [German] Fortschrittliche Multiphasen-Staehle eroeffnen wegen der inzwischen erreichbaren Kombination aus Umformbarkeit und Bauteilfestigkeit ein enormes Potenzial fuer Rohkarosserien. Sie stellen eine erste Wahl dar, wenn es um Festigkeit und um Crashsicherheit geht und besondere Anforderungen an die Bauteilgeometrien gestellt werden. Bei ThyssenKrupp hat die Entwicklung hochfester Multiphasen-Staehle in Verbindung mit dem Feuerverzinken zur Realisierung von Blechhalbzeugen gefuehrt, die hervorragend formbar sind. Es werden heute feuerverzinkte Komplexphasenstaehle neben den bewaehrten kaltgewalzten Dualphasen(DP) - und Retained Austenit(RA)-Staehlen produziert. Die neuen kontinuierlich gegluehten Stahlvarianten mit Festigkeiten bis zu 1000 MPa in Kombination mit der bei Strukturbauteilen im Automobilbau geforderten Duktilitaet nutzen sowohl die klassischen Vorteile des Mikrolegierens aus und dazu die Prinzipien, die man bei DP- und TRIP-Staehlen anwendet. Eine weitere Verbesserung des Eigenschaftsprofils wird mit dem

  11. Practical uses of galvanized steel in electric utility applications

    International Nuclear Information System (INIS)

    Bueche, D.G.

    1995-01-01

    Steel corrosion has been shown to be a major problem for the electric utility industry. Galvanizing has been shown to prevent or substantially slow steel corrosion. This paper describes the galvanizing process, discusses the properties associated with the galvanized coating, and demonstrates galvanizing's durability in specific, real world applications in the electric utility industry

  12. TEXTURE AND MECHANICAL BEHAVIOUR OF Ti AND Nb-Ti STABILIZED IF STEELS

    Directory of Open Access Journals (Sweden)

    Fabio Moreira da Silva Dias

    2013-12-01

    Full Text Available An analysis of the crystallographic texture and mechanical behavior of two types of IF steels is presented. Two steels, Ti and Nb-Ti, were submitted to different thermal annealing cycles in a continuous hot-dip galvanizing line, heat treated at temperatures of 860°C and 760°C. The more relevant characteristics of mechanical properties are evaluated. The crystallographic texture of the samples is determined by electron diffraction technique of back-scattering (SEM-EBSD. The intensity of orientation //ND is evaluated and compared. Metallographic characterization is done, and the ferritic grain size is measured with optical microscopy. The mechanical behavior of materials is characterized in the tensile test with 80 mm gauge length.

  13. Microstructure and High-temperature Wear Behavior of Hot-dipped Aluminized Coating on Different Substrate Materials

    Directory of Open Access Journals (Sweden)

    ZHOU De-qin

    2018-02-01

    Full Text Available The aluminized 45 and H13 steel were prepared via hot-dipped aluminizing and subsequently high-temperature diffusion treatment. The phase, morphology and composition of aluminized coating were characterized by XRD,SEM and EDS methods. Comparative study was performed on unlubricated sliding wear behavior of plating under different substrates on a pin-on-disc wear tester, and the wear mechanism was explored. The results show that the coating is composed of ductile phases FeAl and Fe3Al. Kikendall porosity parallel to the surface exists around the interface of the two phases; because of the carbide particles agglomeration, the bond between the coating and H13 steel is apparently inferior to that in the case of 45 steel; the aluminized 45 steel possesses an excellent wear resistance under 50-200N at 400℃, whereas mild-to-severe wear transition occurs when the temperature increases to 600℃. The wear rate of the aluminized H13 steel reaches the lowest at 400℃, then slightly increases at 600℃. The wear mechanisms of Fe-Al coating are mainly predominated by oxidative mild wear, whereas the extrusion wear prevails in the process for aluminized 45 steel at 600℃.

  14. Dissolved oxygen detection by galvanic displacement-induced

    Indian Academy of Sciences (India)

    Dissolved oxygen detection by galvanic displacement-induced graphene/silver nanocomposite ... dissolved oxygen (DO) detection based on a galvanic displacement synthesized reduced graphene oxide–silver nanoparticles ... Current Issue

  15. Alternativas para o tratamento de efluentes da indústria galvânica Alternatives for the galvanic wastewater treatment

    Directory of Open Access Journals (Sweden)

    Artur Pereira Neto

    2008-09-01

    Full Text Available Os métodos de precipitação química, cristalização e extração líquido-líquido foram aplicados visando propor alternativas para o tratamento de efluentes líquidos gerados pela indústria de galvanoplastia. Efluentes de diversas empresas do setor, localizadas no estado de Minas Gerais (Brasil, foram coletados e caracterizados. O efluente estudado, proveniente de empresa de galvanização de zinco a quente, continha cerca de 90 g/L de ferro total, 35 g/L de zinco e menores quantidades de Al, Ni e Cu, em meio ácido clorídrico (pH = 0,6. A separação seletiva entre ferro e zinco não se mostrou eficiente por precipitação, sendo a técnica adequada somente no tratamento do efluente, ao contrário da cristalização e extração líquido-líquido utilizando-se TBP como agente extratante. A integração destas técnicas ainda requer estudos mais detalhados visando à otimização de custos e das condições operacionais.Separation methods such as chemical precipitation, crystallization and liquid-liquid extraction have been investigated aiming to treat effluents generated by the galvanic industry. Effluent samples generated by several companies located in the state of Minas Gerais (Brazil were collected and chemically characterized. For this work, a typical zinc hot-dip galvanizing effluent containing about 90 g/L of total iron, 35 g/L of zinc and minor amounts of Al, Ni, Cu, in HCl medium (pH = 0.6 was treated. A selective separation between metals zinc and iron was not achieved by chemical precipitation, which was found adequate to threat water only. On contrary, zinc and iron was separated very efficiently by crystallization and liquid-liquid extraction using TBP as extractant agent. The integration of these methods to recover zinc and iron from effluent still requires more detailed studies.

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

    Science.gov (United States)

    Zhu, Jun

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-12-15

    Apart from reliability and quality, vehicle safety and cost efficiency are the decisive criteria for automobile manufacturers. Corrosion protection plays a decisive role because it increases the service life. The ultra-high-strength steels are materials which exhibit high lightweight potential as well as a very good energy absorption capacity because of their mechanical properties. In connection with the possibility of hot forming, they are predestined for the fabrication of complicated, load-compatible shapes in the crash-relevant frame and body construction. The application of these steel qualities has been carried out in structural parts which are protected from corrosion by a hot-dip coat of FeAl7 - the so-called Usibor. However, at the moment there is no ready-for-production solution for later corrosion protection of already hot-formed parts. Therefore, a corrosion protection system on the basis of conventional low-temperature galvanizing processes has been developed and utilized. First, the softening behavior of the highly-resistant 22MnB5 substrate was analyzed. Afterwards, a galvanizing system was developed and applied. The corrosion protection coatings were characterized with regard to their structure and corrosion protection potential. As a result, a significant improvement of the corrosion behaviour has occurred. (Abstract Copyright [2008], Wiley Periodicals, Inc.) [German] Neben Zuverlaessigkeit und Qualitaet sind vor allem Fahrzeugsicherheit und Wirtschaftlichkeit entscheidende Kriterien fuer den Automobilhersteller. Der Korrosionsschutz spielt dabei eine herausragende Rolle, da hierdurch die Lebens- und Gebrauchsdauer erhoeht wird. Mit der Bereitstellung hoechstfester Stahlqualitaeten stehen Werkstoffe zur Verfuegung, die auf Grund ihrer mechanischen Eigenschaften ein hohes Leichtbaupotenzial sowie ein sehr gutes Energieabsorptionsvermoegen aufweisen. In Verbindung mit der Moeglichkeit der Warmformgebung sind sie damit praedestiniert fuer die

  18. Flow-accelerated corrosion characteristics of galvanically coupled dissimilar metals

    International Nuclear Information System (INIS)

    Choi, Yoon Seok; Kim, Jnng Gu

    2001-01-01

    Flow accelerated galvanic corrosion characteristics of a carbon steel coupled to stainless steel were investigated in deaerated alkaline-chloride solutions as a function of flow velocities, pH and temperatures. The electrochemical properties of specimens were investigated by potentiodynamic test and galvanic corrosion test using RCE(Rotating Cylinder Electrode). Carbon steel showed active behavior in the deaerated alkaline-chloride solution. The galvanic current density of carbon steel increased with increasing flow velocity and temperature, but decreased with increasing pH. Flow velocity had a small effect on the galvanic current density at 25 deg. C, whereas the flow velocity increased galvanic current density significantly at 50 .deg. C and 75 .deg. C. This might be due to the increased solubility of magnetite at the higher temperatures

  19. Galvanic manifestation of spontaneous coherence in the negative glow

    International Nuclear Information System (INIS)

    Zhechev, D; Parvanova, N

    2002-01-01

    Both the magnetic depolarization of the spontaneous emission from self-aligned states and the discharge galvanic reaction are measured simultaneously in a magnetic field. The observed galvanic peak is ascribed to magnetic destruction of self-aligned ensembles of atoms. This presents galvanic manifestation of coherent conductivity. (letter to the editor)

  20. Influence of silicon on hot-dip aluminizing process and subsequent oxidation for preparing hydrogen/tritium permeation barrier

    Energy Technology Data Exchange (ETDEWEB)

    Han, Shilei; Li, Hualing; Wang, Shumao; Jiang, Lijun; Liu, Xiaopeng [Energy Materials and Technology Research Institute, General Research Institute for Nonferrous Metals, Beijing 100088 (China)

    2010-04-15

    The development of the International Thermonuclear Experimental Reactor (ITER) requires the production of a material capable of acting as a hydrogen/tritium permeation barrier on low activation steel. It is well known that thin alumina layer can reduce the hydrogen permeation rate by several orders of magnitude. A technology is introduced here to form a ductile Fe/Al intermetallic layer on the steel with an alumina over-layer. This technology, consisting of two main steps, hot-dip aluminizing (HDA) and subsequent oxidation behavior, seems to be a promising coating method to fulfill the required goals. According to the experiments that have been done in pure Al, the coatings were inhomogeneous and too thick. Additionally, a large number of cracks and porous band could be observed. In order to solve these problems, the element silicon was added to the aluminum melt with a nominal composition. The influence of silicon on the aluminizing and following oxidation process was investigated. With the addition of silicon into the aluminum melt, the coating became thinner and more homogeneous. The effort of the silicon on the oxidation behavior was observed as well concerning the suppression of porous band and cracks. (author)

  1. Multifunctional Metallic and Refractory Materials for Energy Efficient Handling of Molten Metals

    Energy Technology Data Exchange (ETDEWEB)

    Xingbo Liu; Ever Barbero; Bruce Kang; Bhaskaran Gopalakrishnan; James Headrick; Carl Irwin

    2009-02-06

    The goal of the project was to extend the lifetime of hardware submerged in molten metal by an order of magnitude and to improve energy efficiency of molten metal handling process. Assuming broad implementation of project results, energy savings in 2020 were projected to be 10 trillion BTU/year, with cost savings of approximately $100 million/year. The project team was comprised of materials research groups from West Virginia University and the Missouri University of Science and Technology formerly University of Missouri – Rolla, Oak Ridge National Laboratory, International Lead and Zinc Research Organization, Secat and Energy Industries of Ohio. Industry partners included six suppliers to the hot dip galvanizing industry, four end-user steel companies with hot-dip Galvanize and/or Galvalume lines, eight refractory suppliers, and seven refractory end-user companies. The results of the project included the development of: (1) New families of materials more resistant to degradation in hot-dip galvanizing bath conditions were developed; (2) Alloy 2020 weld overlay material and process were developed and applied to GI rolls; (3) New Alloys and dross-cleaning procedures were developed for Galvalume processes; (4) Two new refractory compositions, including new anti-wetting agents, were identified for use with liquid aluminum alloys; (5) A new thermal conductivity measurement technique was developed and validated at ORNL; (6) The Galvanizing Energy Profiler Decision Support System (GEPDSS)at WVU; Newly Developed CCW Laser Cladding Shows Better Resistance to Dross Buildup than 316L Stainless Steel; and (7) A novel method of measuring the corrosion behavior of bath hardware materials. Project in-line trials were conducted at Southwire Kentucky Rod and Cable Mill, Nucor-Crawfordsville, Nucor-Arkansas, Nucor-South Carolina, Wheeling Nisshin, California Steel, Energy Industries of Ohio, and Pennex Aluminum. Cost, energy, and environmental benefits resulting from the project

  2. High chromium nickel base alloys hot cracking susceptibility

    International Nuclear Information System (INIS)

    Tirand, G.; Primault, C.; Robin, V.

    2014-01-01

    High Chromium nickel based alloys (FM52) have a higher ductility dip cracking sensitivity. New filler material with higher niobium and molybdenum content are developed to decrease the hot crack formation. The behavior of these materials is studied by coupling microstructural analyses and hot cracking test, PVR test. The metallurgical analyses illustrate an Nb and Mo enrichment of the inter-dendritic spaces of the new materials. A niobium high content (FM52MSS) induces the formation of primary carbide at the end of solidification. The PVR test reveal a solidification crack sensitivity of the new materials, and a lowest ductility dip cracking sensitivity for the filler material 52MSS. (authors)

  3. Effect of UV-C radiation and hot water on the calcium content and postharvest quality of apples

    International Nuclear Information System (INIS)

    Hemmaty, S.; Moallemi, N.; Naseri, L.

    2007-01-01

    To increase the storage shelf life of 'Red Delicious' and 'Golden Delicious' apples they were treated with UV-C irradiation at doses of 0, 5 and 15 min irradiation at 1.435 x 10 -4 W/square cm - and with hot water containing 4% CaCl 2 at four levels (control, dipping at 25 deg C for 10 min, dipping at 38 deg C for 5 min and dipping in 54 deg C for 1 min) in a factorial design with 4 replicates. The results showed that UV-C irradiation and dipping of fruit in hot water increased the storage life and improved fruit quality factors in 'Red Delicious' and 'Golden Delicious' apples at the end of cold storage. Both UV-C and hot water treatments decreased pH and total soluble solids/titratable acids ratio and increased fruit titratable acids and firmness. UV-C and hot water treatment increased fruit Ca content during storage. The results showed that UV-C and hot water treatment can retard fruit ripening and maintain fruit quality in cold storage. These treatments can also increase Ca concentration of fruit flesh and thus increase the nutritional value of the apples. (author) [es

  4. Complex approach mechanical properties and formability assessment of selected deep-drawing steels

    OpenAIRE

    J. Štaba; M. Buršák

    2009-01-01

    The paper analyses the properties of deep-drawing sheets of three grades (Re = 320 to 475 MPa), surface-treated with hot-dip galvanizing, made of microalloyed steels. Deformation properties are assessed using tensile tests, technological Erichsen or cupping tests. These characteristics, as well as the behaviour of the surface layer, are also investigated under dynamic conditions (modified Erichsen test using a drop tester), or using flat bending fatigue tests. Using microscopic analysis the d...

  5. Structural Controls of Neal Hot Springs Geothermal Field, Malhuer County, Oregon

    Science.gov (United States)

    Edwards, J. H.; Faulds, J. E.

    2012-12-01

    Detailed mapping (1:24,000) of the Neal Hot Springs area (90 km2) in eastern Oregon is part of a larger study of geothermal systems in the Basin and Range, which focuses on the structural controls of geothermal activity. The study area lies within the intersection of two regional grabens, the middle-late Miocene, N-striking, Oregon-Idaho graben and younger late Miocene to Holocene, NW-striking, western Snake River Plain graben. The geothermal field is marked by Neal Hot Springs, which effuse from opaline sinter mounds just north of Bully Creek. Wells producing geothermal fluids, with temperatures at 138°C, intersect a major, W-dipping, NNW-striking, high-angle normal fault at depths of 850-915 m. Displacement along this structure dies southward, with likely horse-tailing, which commonly produces high fracture density and a zone of high permeability conducive for channeling hydrothermal fluids. Mapping reveals that the geothermal resource lies within a local, left step-over. 'Hard-linkage' between strands of the left-stepping normal fault, revealed through a study of well chips and well logs, occurs through two concealed structures. Both are W-striking faults, with one that runs parallel to Cottonwood Creek and one 0.5 km N of the creek. Injection wells intersect these two transverse structures within the step-over. Stepping and displacement continue to the NW of the known geothermal field, along W-dipping, N-striking faults that cut lower to middle Miocene Hog Creek Formation, consisting of silicic and mafic volcanic rocks. These N-striking faults were likely initiated during initial Oregon-Idaho graben subsidence (15.3-15.1 Ma), with continued development through late Miocene. Bully Creek Formation deposits, middle to upper Miocene lacustrine and pyroclastic rocks, concomitantly filled the sub half-grabens, and they dip gently to moderately eastward. Younger, western Snake River Plain deposits, upper Miocene to Pliocene fluvial, lacustrine, and pyroclastic rocks

  6. Study on the Formation of Reaction Phase to Si Addition in Boron Steel Hot-Dipped in Al–7Ni Alloy

    Directory of Open Access Journals (Sweden)

    Jung-Gil Yun

    2017-11-01

    Full Text Available In order to reduce the intermetallic compounds formed during the application of an Al–7Ni wt % hot-dip multifunctional coating on boron steel, developed for Tailor Welded Blanks (TWB and hot stamping, 2–6 wt % Si was added to the coating to change the reaction layer. The coating was run at 690 °C for 120 s. Al9FeNi phases were formed on the steel interface, Fe2Al5 was formed on the steel, FeAl3 was generated between the existing layers, and flake-type Al2Fe3Si3 was formed in the Fe2Al5 phase, depending on the Si content. In addition, as Si was added to the coating, the thickness of the Fe2Al5 phase decreased and the thickness of the Al9FeNi phase and Al2Fe3Si3 increased. The decrease in the thickness of the Fe2Al5 phase was mainly due to the effect of the Si solid solution and the Al2Fe3Si3 formation in the Fe2Al5 phase. The reason for the growth of Al9FeNi is that the higher the Si content in the coating, the more the erosion of the interface of the steel material due to the coating solution. Therefore, the outflow of Fe into the coating liquid increased.

  7. Corrosion of Galvanized Steel Under Different Soil Moisture Contents

    OpenAIRE

    Pereira,Roseana Florentino da Costa; Oliveira,Edkarlla Sousa Dantas de; Lima,Maria Alice Gomes de Andrade; Brasil,Simone Louise Delarue Cezar

    2015-01-01

    Galvanized steel has been widely applied in different applications and the industry significantly increased its production in recent years. Some galvanized structures can be completely or partially buried, such as transmission tower footings. The corrosion of these metallic structures is related to the soil chemical and physicochemical properties, which define the aggressiveness of the environment. To assess the effect of the soil moisture on galvanized steel corrosion, a comparative study wa...

  8. Galvanic cell for processing of used nuclear fuel

    Science.gov (United States)

    Garcia-Diaz, Brenda L.; Martinez-Rodriguez, Michael J.; Gray, Joshua R.; Olson, Luke C.

    2017-02-07

    A galvanic cell and methods of using the galvanic cell is described for the recovery of uranium from used nuclear fuel according to an electrofluorination process. The galvanic cell requires no input energy and can utilize relatively benign gaseous fluorinating agents. Uranium can be recovered from used nuclear fuel in the form of gaseous uranium compound such as uranium hexafluoride, which can then be converted to metallic uranium or UO.sub.2 and processed according to known methodology to form a useful product, e.g., fuel pellets for use in a commercial energy production system.

  9. 76 FR 29266 - Galvanized Steel Wire From China and Mexico

    Science.gov (United States)

    2011-05-20

    ...)] Galvanized Steel Wire From China and Mexico Determinations On the basis of the record \\1\\ developed in the... reason of imports from China and Mexico of galvanized steel wire, provided for in subheading 7217.20.30... subsidized imports of galvanized steel wire from China and Mexico. Accordingly, effective March 31, 2011, the...

  10. Effects of Mn addition on the microstructure and indentation creep behavior of the hot dip Zn coating

    International Nuclear Information System (INIS)

    Wang, Youbin; Zeng, Jianmin

    2015-01-01

    Highlights: • Mn addition could significantly refine the grain of the Zn coating. • Twins could be observed in the Zn coatings. • The stress exponent of the Zn coating increases with Mn addition. • The creep process of the Zn coating is dominated by dislocation climb and twins. - Abstract: The Zn coatings with different Mn additions were prepared by hot dip process, and the effects of the Mn addition on the microstructure and indentation creep behavior of the coatings were investigated through scanning electron microscope and constant-load holding indentation technique at the room temperature. Some twins can be observed in the microstructure of Zn coating, which may account for the formation of the large thermal misfit stress between the zinc coating and the steel substrate. The amount of twin microstructure in the Zn coating decreases with the Mn addition. It is also found that Mn addition could induce MnZn 13 phases to precipitate along the grain boundary and significantly refine the grains of Zn coatings. The steady-state stress of the Zn coating could be improved by Mn addition. The creep stress exponent values are in the range of 14–46 and increases with Mn addition. The creep process of the Zn coating is dominated by dislocation climb and twin formation

  11. Cr(VI) reduction in wastewater using a bimetallic galvanic reactor

    International Nuclear Information System (INIS)

    Lugo-Lugo, Violeta; Barrera-Diaz, Carlos; Bilyeu, Bryan; Balderas-Hernandez, Patricia; Urena-Nunez, Fernando; Sanchez-Mendieta, Victor

    2010-01-01

    The electrochemical reduction of Cr(VI)-Cr(III) in wastewater by iron and copper-iron bimetallic plates was evaluated and optimized. Iron has been used as a reducing agent, but in this work a copper-iron galvanic system in the form of bimetallic plates is applied to reducing hexavalent chromium. The optimal pH (2) and ratio of copper to iron surface areas (3.5:1) were determined in batch studies, achieving a 100% reduction in about 25 min. The Cr(VI) reduction kinetics for the bimetallic system fit a first order mechanism with a correlation of 0.9935. Thermodynamic analysis shows that the Cr(VI) reduction is possible at any pH value. However, at pH values above 3.0 for iron and 5.5 for chromium insoluble species appear, indicating that the reaction will be hindered. Continuous column studies indicate that the bimetallic copper-iron galvanic system has a reduction capacity of 9.5890 mg Cr(VI) cm -2 iron, whereas iron alone only has a capacity of 0.1269 mg Cr(VI) cm -2 . The bimetallic copper-iron galvanic system is much more effective in reducing hexavalent chromium than iron alone. The exhausted plates were analyzed by SEM, EDS, and XRD to determine the mechanism and the surface effects, especially surface fouling.

  12. 77 FR 28404 - Galvanized Steel Wire From China and Mexico

    Science.gov (United States)

    2012-05-14

    ...)] Galvanized Steel Wire From China and Mexico Determinations On the basis of the record \\1\\ developed in the... reason of imports from Mexico of galvanized steel wire, provided for in subheadings 7217.20.30, 7217.20... galvanized steel wire from China and Mexico were sold at LTFV within the meaning of 733(b) of the Act (19 U.S...

  13. Properties of Galvanized and Galvannealed Advanced High Strength Hot Rolled Steels

    Energy Technology Data Exchange (ETDEWEB)

    V.Y. Guertsman; E. Essadiqi; S. Dionne; O. Dremmailova; R. Bouchard; B. Voyzelle; J. McDermid; R. Fourmentin

    2008-04-01

    The objectives of the project were (i) to develop the coating process information to achieve good quality coatings on 3 advanced high strength hot rolled steels while retaining target mechanical properties, (ii) to obtain precise knowledge of the behavior of these steels in the various forming operations and (iii) to establish accurate user property data in the coated conditions. Three steel substrates (HSLA, DP, TRIP) with compositions providing yield strengths in the range of 400-620 MPa were selected. Only HSLA steel was found to be suitable for galnaizing and galvannealing in the hot rolled condition.

  14. Galvanic corrosion in odontological alloys

    International Nuclear Information System (INIS)

    Riesgo, O.; Bianchi, G.L.; Duffo, G.S.

    1993-01-01

    Galvanic corrosion can occur when different alloys are placed in direct contact within the oral cavity or within tissues. Concern has been expressed associated with the coupling of selected restorative materials as well as implant material with various alloys used for restorative procedures. This could be critical if the crown or bridge had subgingival finish line with a metallic zone in contact with the tissue, and the implant was made in titanium alloy. The present work shows the results of galvanic coupling studies done on implants of titanium alloy connected to nickel-chromium and cobalt-chromium alloys. (Author)

  15. Scalable, "Dip-and-Dry" Fabrication of a Wide-Angle Plasmonic Selective Absorber for High-Efficiency Solar-Thermal Energy Conversion.

    Science.gov (United States)

    Mandal, Jyotirmoy; Wang, Derek; Overvig, Adam C; Shi, Norman N; Paley, Daniel; Zangiabadi, Amirali; Cheng, Qian; Barmak, Katayun; Yu, Nanfang; Yang, Yuan

    2017-11-01

    A galvanic-displacement-reaction-based, room-temperature "dip-and-dry" technique is demonstrated for fabricating selectively solar-absorbing plasmonic-nanoparticle-coated foils (PNFs). The technique, which allows for facile tuning of the PNFs' spectral reflectance to suit different radiative and thermal environments, yields PNFs which exhibit excellent, wide-angle solar absorptance (0.96 at 15°, to 0.97 at 35°, to 0.79 at 80°), and low hemispherical thermal emittance (0.10) without the aid of antireflection coatings. The thermal emittance is on par with those of notable selective solar absorbers (SSAs) in the literature, while the wide-angle solar absorptance surpasses those of previously reported SSAs with comparable optical selectivities. In addition, the PNFs show promising mechanical and thermal stabilities at temperatures of up to 200 °C. Along with the performance of the PNFs, the simplicity, inexpensiveness, and environmental friendliness of the "dip-and-dry" technique makes it an appealing alternative to current methods for fabricating selective solar absorbers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Galvanic corrosion of copper-cast iron couples

    International Nuclear Information System (INIS)

    Smart, N.R.; Rance, A.P.; Fennell, P.A.H.

    2005-01-01

    To ensure the safe encapsulation of spent nuclear fuel rods for geological disposal, SKB are considering using the Copper-Cast Iron Canister, which consists of an outer copper canister and an inner cast iron container. The canister will be placed into boreholes in the bedrock of a geologic repository and surrounded by bentonite clay. In the unlikely event of the outer copper canister being breached, water would enter the annulus between the inner and outer canister and at points of contact between the two metals there would be the possibility of galvanic interactions. Although this subject has been considered previously from both a theoretical standpoint and by experimental investigations there was a need for further experimental studies in support of information provided by SKB to the Swedish regulators (SKI). In the work reported here copper-cast iron galvanic couples were set up in a number of different environments representing possible conditions in the SKB repository. The tests investigated two artificial porewaters at 30 deg C and 50 deg C, under aerated and deaerated conditions. Tests were also carried out in a 30 wt% bentonite slurry made up in artificial groundwater. The potential of the couples and the currents passing between the coupled electrodes were monitored for several months. The effect of growing an oxide film on the surface of the cast iron prior to coupling it with copper was investigated. In addition, some crevice specimens based on the multi-crevice assembly (MCA) design were used to simulate the situation where the copper canister will be in direct contact with the cast iron inner vessel. The electrochemical results are presented graphically in the form of electrode potentials and galvanic corrosion currents as a function of time. The galvanic currents in aerated conditions were much higher than in deaerated conditions. For example, at 30 deg C, galvanic corrosion rates as low as 0.02 μm/year for iron were observed after deaeration, but

  17. Failure analysis of edge discoloration of galvanized fuel tank

    Directory of Open Access Journals (Sweden)

    Jitendra Mathur

    2015-10-01

    Full Text Available A peculiar type of edge discoloration defect on the surface of some galvanized fuel tank was observed, causing significant appearance problems. In the present study, the surface defect was characterized by visual inspection, optical microscopy, scanning electron microscopy and energy dispersive spectroscopic analysis to understand the source and mechanism of the defect. In the visual inspection, these peculiar surface appearances were observed in fuel tank at three distinct locations. The SEM examination exhibited two distinct regions on the surface apart from the normal galvanized surface: (1 galvannealed, (2 mixture of galvanized and galvannealed texture. The energy dispersive spectroscopic analysis of galvannealed region indicated enrichment of Zn and Al whereas in the region of galvanized majorly Zn was observed. Surface texture of galvannealed region showed majorly zeta crystals along with skin pass marks; whereas no such zeta crystals were observed in case of galvanized regions. Based on the preliminary results, the following hypothesis was made: Coil processed during galvanizing to galvannealing transition. Thickness and width changed to wider and thicker section, which resulted into lower line speed. Due to the lower Al content, lower speed and thicker section combination resulted in formation of partial GA in the coil owing to the internal heat content of the coil. This paper presents the results of the investigation.

  18. A Cellular Automaton / Finite Element model for predicting grain texture development in galvanized coatings

    Science.gov (United States)

    Guillemot, G.; Avettand-Fènoël, M.-N.; Iosta, A.; Foct, J.

    2011-01-01

    Hot-dipping galvanizing process is a widely used and efficient way to protect steel from corrosion. We propose to master the microstructure of zinc grains by investigating the relevant process parameters. In order to improve the texture of this coating, we model grain nucleation and growth processes and simulate the zinc solid phase development. A coupling scheme model has been applied with this aim. This model improves a previous two-dimensional model of the solidification process. It couples a cellular automaton (CA) approach and a finite element (FE) method. CA grid and FE mesh are superimposed on the same domain. The grain development is simulated at the micro-scale based on the CA grid. A nucleation law is defined using a Gaussian probability and a random set of nucleating cells. A crystallographic orientation is defined for each one with a choice of Euler's angle (Ψ,θ,φ). A small growing shape is then associated to each cell in the mushy domain and a dendrite tip kinetics is defined using the model of Kurz [2]. The six directions of basal plane and the two perpendicular directions develop in each mushy cell. During each time step, cell temperature and solid fraction are then determined at micro-scale using the enthalpy conservation relation and variations are reassigned at macro-scale. This coupling scheme model enables to simulate the three-dimensional growing kinetics of the zinc grain in a two-dimensional approach. Grain structure evolutions for various cooling times have been simulated. Final grain structure has been compared to EBSD measurements. We show that the preferentially growth of dendrite arms in the basal plane of zinc grains is correctly predicted. The described coupling scheme model could be applied for simulated other product or manufacturing processes. It constitutes an approach gathering both micro and macro scale models.

  19. The First Post-Kepler Brightness Dips of KIC 8462852

    Science.gov (United States)

    Boyajian, Tabetha. S.; Alonso, Roi; Ammerman, Alex; Armstrong, David; Asensio Ramos, A.; Barkaoui, K.; Beatty, Thomas G.; Benkhaldoun, Z.; Benni, Paul; Bentley, Rory O.; Berdyugin, Andrei; Berdyugina, Svetlana; Bergeron, Serge; Bieryla, Allyson; Blain, Michaela G.; Capetillo Blanco, Alicia; Bodman, Eva H. L.; Boucher, Anne; Bradley, Mark; Brincat, Stephen M.; Brink, Thomas G.; Briol, John; Brown, David J. A.; Budaj, J.; Burdanov, A.; Cale, B.; Aznar Carbo, Miguel; Castillo García, R.; Clark, Wendy J.; Clayton, Geoffrey C.; Clem, James L.; Coker, Phillip H.; Cook, Evan M.; Copperwheat, Chris M.; Curtis, J. L.; Cutri, R. M.; Cseh, B.; Cynamon, C. H.; Daniels, Alex J.; Davenport, James R. A.; Deeg, Hans J.; De Lorenzo, Roberto; de Jaeger, Thomas; Desrosiers, Jean-Bruno; Dolan, John; Dowhos, D. J.; Dubois, Franky; Durkee, R.; Dvorak, Shawn; Easley, Lynn; Edwards, N.; Ellis, Tyler G.; Erdelyi, Emery; Ertel, Steve; Farfán, Rafael. G.; Farihi, J.; Filippenko, Alexei V.; Foxell, Emma; Gandolfi, Davide; Garcia, Faustino; Giddens, F.; Gillon, M.; González-Carballo, Juan-Luis; González-Fernández, C.; González Hernández, J. I.; Graham, Keith A.; Greene, Kenton A.; Gregorio, J.; Hallakoun, Na’ama; Hanyecz, Ottó; Harp, G. R.; Henry, Gregory W.; Herrero, E.; Hildbold, Caleb F.; Hinzel, D.; Holgado, G.; Ignácz, Bernadett; Ilyin, Ilya; Ivanov, Valentin D.; Jehin, E.; Jermak, Helen E.; Johnston, Steve; Kafka, S.; Kalup, Csilla; Kardasis, Emmanuel; Kaspi, Shai; Kennedy, Grant M.; Kiefer, F.; Kielty, C. L.; Kessler, Dennis; Kiiskinen, H.; Killestein, T. L.; King, Ronald A.; Kollar, V.; Korhonen, H.; Kotnik, C.; Könyves-Tóth, Réka; Kriskovics, Levente; Krumm, Nathan; Krushinsky, Vadim; Kundra, E.; Lachapelle, Francois-Rene; LaCourse, D.; Lake, P.; Lam, Kristine; Lamb, Gavin P.; Lane, Dave; Lau, Marie Wingyee; Lewin, Pablo; Lintott, Chris; Lisse, Carey; Logie, Ludwig; Longeard, Nicolas; Lopez Villanueva, M.; Whit Ludington, E.; Mainzer, A.; Malo, Lison; Maloney, Chris; Mann, A.; Mantero, A.; Marengo, Massimo; Marchant, Jon; Martínez González, M. J.; Masiero, Joseph R.; Mauerhan, Jon C.; McCormac, James; McNeely, Aaron; Meng, Huan Y. A.; Miller, Mike; Molnar, Lawrence A.; Morales, J. C.; Morris, Brett M.; Muterspaugh, Matthew W.; Nespral, David; Nugent, C. R.; Nugent, Katherine M.; Odasso, A.; O’Keeffe, Derek; Oksanen, A.; O’Meara, John M.; Ordasi, András; Osborn, Hugh; Ott, John J.; Parks, J. R.; Rodriguez Perez, Diego; Petriew, Vance; Pickard, R.; Pál, András; Plavchan, P.; Pollacco, Don; Pozo Nuñez, F.; Pozuelos, F. J.; Rau, Steve; Redfield, Seth; Relles, Howard; Ribas, Ignasi; Richards, Jon; Saario, Joonas L. O.; Safron, Emily J.; Sallai, J. Martin; Sárneczky, Krisztián; Schaefer, Bradley E.; Schumer, Clea F.; Schwartzendruber, Madison; Siegel, Michael H.; Siemion, Andrew P. V.; Simmons, Brooke D.; Simon, Joshua D.; Simón-Díaz, S.; Sitko, Michael L.; Socas-Navarro, Hector; Sódor, Á.; Starkey, Donn; Steele, Iain A.; Stone, Geoff; Strassmeier, Klaus G.; Street, R. A.; Sullivan, Tricia; Suomela, J.; Swift, J. J.; Szabó, Gyula M.; Szabó, Róbert; Szakáts, Róbert; Szalai, Tamás; Tanner, Angelle M.; Toledo-Padrón, B.; Tordai, Tamás; Triaud, Amaury H. M. J.; Turner, Jake D.; Ulowetz, Joseph H.; Urbanik, Marian; Vanaverbeke, Siegfried; Vanderburg, Andrew; Vida, Krisztián; Vietje, Brad P.; Vinkó, József; von Braun, K.; Waagen, Elizabeth O.; Walsh, Dan; Watson, Christopher A.; Weir, R. C.; Wenzel, Klaus; Westendorp Plaza, C.; Williamson, Michael W.; Wright, Jason T.; Wyatt, M. C.; Zheng, WeiKang; Zsidi, Gabriella

    2018-01-01

    We present a photometric detection of the first brightness dips of the unique variable star KIC 8462852 since the end of the Kepler space mission in 2013 May. Our regular photometric surveillance started in 2015 October, and a sequence of dipping began in 2017 May continuing on through the end of 2017, when the star was no longer visible from Earth. We distinguish four main 1%–2.5% dips, named “Elsie,” “Celeste,” “Skara Brae,” and “Angkor,” which persist on timescales from several days to weeks. Our main results so far are as follows: (i) there are no apparent changes of the stellar spectrum or polarization during the dips and (ii) the multiband photometry of the dips shows differential reddening favoring non-gray extinction. Therefore, our data are inconsistent with dip models that invoke optically thick material, but rather they are in-line with predictions for an occulter consisting primarily of ordinary dust, where much of the material must be optically thin with a size scale ≪1 μm, and may also be consistent with models invoking variations intrinsic to the stellar photosphere. Notably, our data do not place constraints on the color of the longer-term “secular” dimming, which may be caused by independent processes, or probe different regimes of a single process.

  20. Laboratory studies of galvanic corrosion. I. Two-metal couples

    International Nuclear Information System (INIS)

    Mansfeld, F.; Kenkel, J.V.

    1975-01-01

    Galvanic interaction of stainless steel 304L, Ni 270, Cu, Ti--6Al--4V, Sn, 4130 steel, Cd, and Zn has been studied in 3.5 percent NaCl using galvanic current and weight loss measurements in 24-hour tests. Galvanic couples of 4130 steel and one of the Al alloys 1100, 2024, 2219, 6061, and 7075 have also been evaluated in tap water and distilled water. Galvanic current data can be used to assess both the effect of different dissimilar cathode materials as well as the relative susceptibility to galvanic corrosion of anode materials. For 3.5 percent NaCl, it has been found that the effect of the cathode material decreases in the order Cu greater than Ni greater than stainless steel greater than Ti--6Al--4V, while the relative susceptibility of anode materials decreases in the order Sn greater than Zn greater than 4130 steel greater than Cd. An analysis of data in various electrolytes shows that coupling of 4130 steel to Al alloys leads to cathodic protection of the steel in 3.5 percent NaCl, but to accelerated corrosion in tap water and distilled water. (U.S.)

  1. Galvanic Corrosion between Alloy 690 and Magnetite in Alkaline Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Soon-Hyeok Jeon

    2015-12-01

    Full Text Available The galvanic corrosion behavior of Alloy 690 coupled with magnetite has been investigated in an alkaline solution at 30 °C and 60 °C using a potentiodynamic polarization method and a zero resistance ammeter. The positive current values were recorded in the galvanic couple and the corrosion potential of Alloy 690 was relatively lower. These results indicate that Alloy 690 behaves as the anode of the pair. The galvanic coupling between Alloy 690 and magnetite increased the corrosion rate of Alloy 690. The temperature increase led to an increase in the extent of galvanic effect and a decrease in the stability of passive film. Galvanic effect between Alloy 690 and magnetite is proposed as an additional factor accelerating the corrosion rate of Alloy 690 steam generator tubing in secondary water.

  2. Hot working effect on austenite transformations in structural steel in continuous cooling

    International Nuclear Information System (INIS)

    Zajmovskij, V.A.; Kisteh, N.V.; Samedov, O.V.

    1979-01-01

    Austenite transformations in 40, 40Kh, 40KhN and 40KhNMA steels under hot working at 900 deg C with 20% reduction degree and continuous cooling with 1,7-16 0 /s are investigated. Changing of cooling rate in various ways affects the temperature range of austenite transformation in pearlite and bainite regions. Regulating the cooling rate after hot working one can essentially change the impact strength and steel ductility as a result of high temperature thermomechanical treatment effect

  3. Epitaxial growth by monolayer restricted galvanic displacement

    Directory of Open Access Journals (Sweden)

    Vasilić Rastko

    2012-01-01

    Full Text Available The development of a new method for epitaxial growth of metals in solution by galvanic displacement of layers pre-deposited by underpotential deposition (UPD was discussed and experimentally illustrated throughout the lecture. Cyclic voltammetry (CV and scanning tunneling microscopy (STM are employed to carry out and monitor a “quasi-perfect”, two-dimensional growth of Ag on Au(111, Cu on Ag(111, and Cu on Au(111 by repetitive galvanic displacement of underpotentially deposited monolayers. A comparative study emphasizes the displacement stoichiometry as an efficient tool for thickness control during the deposition process and as a key parameter that affects the deposit morphology. The excellent quality of layers deposited by monolayer-restricted galvanic displacement is manifested by a steady UPD voltammetry and ascertained by a flat and uniform surface morphology maintained during the entire growth process.

  4. Ecological and economic assessment and optimisation of measures for in-house recycling in hot galvanizing plants; Oekologische und oekonomische Beurteilung und Optimierung von Massnahmen zur innerbetrieblichen Stoffkreislaufschliessung beim Feuerverzinken von Stahl

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, R.; Fleischer, G. [TU Berlin, Inst. fuer Technischen Umweltschutz, Lehrstuhl Abfallvermeidung und Sekundaerrohstoffwirtschaft, Berlin (Germany)

    2003-07-01

    Exemplary strategies for materials use and recycling in a plant for hot galvanizing of steel are reviewed from an ecological and economic viewpoint and optimized. The changes resulting from the optimization measures are assessed in terms of cost and potential ecological effects. The results of this assessment, which is based on the methodology published in DIN EN ISO 14040 ff, illustrate the potential contained in the recycling option. (orig.) [German] Fuer das Feuerverzinken von Stahlbauteilen werden beispielhaft Strategien zur innerbetrieblichen Stoffkreislaufschliessung oekologisch und oekonomisch beurteilt und optimiert. Die sich hinsichtlich der betrieblichen Stoff- und Energiefluesse durch Optimierungsmassnahmen ergebenden Veraenderungen werden in Bezug auf die Kostensituation des Unternehmens und die oekologischen potentiellen Auswirkungen beurteilt. Die Ergebnisse der Oekologischen Betriebsoptimierung, die unter Nutzung methodischer Elemente der Oekobilanzierung (DIN EN ISO 14040 ff) erzielt werden, verdeutlichen, welche Potentiale in einer weitgehenden Schliessung des Stoffkreislaufs liegen. (orig.)

  5. Fault diagnosis and comparing risk for the steel coil manufacturing process using statistical models for binary data

    International Nuclear Information System (INIS)

    Debón, A.; Carlos Garcia-Díaz, J.

    2012-01-01

    Advanced statistical models can help industry to design more economical and rational investment plans. Fault detection and diagnosis is an important problem in continuous hot dip galvanizing. Increasingly stringent quality requirements in the automotive industry also require ongoing efforts in process control to make processes more robust. Robust methods for estimating the quality of galvanized steel coils are an important tool for the comprehensive monitoring of the performance of the manufacturing process. This study applies different statistical regression models: generalized linear models, generalized additive models and classification trees to estimate the quality of galvanized steel coils on the basis of short time histories. The data, consisting of 48 galvanized steel coils, was divided into sets of conforming and nonconforming coils. Five variables were selected for monitoring the process: steel strip velocity and four bath temperatures. The present paper reports a comparative evaluation of statistical models for binary data using Receiver Operating Characteristic (ROC) curves. A ROC curve is a graph or a technique for visualizing, organizing and selecting classifiers based on their performance. The purpose of this paper is to examine their use in research to obtain the best model to predict defective steel coil probability. In relation to the work of other authors who only propose goodness of fit statistics, we should highlight one distinctive feature of the methodology presented here, which is the possibility of comparing the different models with ROC graphs which are based on model classification performance. Finally, the results are validated by bootstrap procedures.

  6. A Galvanic Sensor for Monitoring the Corrosion Condition of the Concrete Reinforcing Steel: Relationship Between the Galvanic and the Corrosion Currents

    Directory of Open Access Journals (Sweden)

    Elsa Vaz Pereira

    2009-10-01

    Full Text Available This work reports a study carried out on the design and performance of galvanic and polarization resistance sensors to be embedded in concrete systems for permanent monitoring of the corrosion condition of reinforcing steel, aiming to establish a correlation between the galvanic currents, Igal, and the corrosion currents, Icorr, estimated from the polarization resistance, Rp. Sensors have been tested in saturated Ca(OH2 aqueous solutions, under a variety of conditions, simulating the most important parameters that can accelerate the corrosion of concrete reinforcing steel, such as carbonation, ingress of chloride ions, presence or absence of O2. For all the conditions, the influence of temperature (20 to 55 ºC has also been considered. From this study, it could be concluded that the galvanic currents are sensitive to the various parameters following a trend similar to that of the Rp values. A relationship between the galvanic and the corrosion current densities was obtained and the limiting values of the Igal, indicative of the state condition of the reinforcing steel for the designed sensor, were established.

  7. Intermediate Latency-Evoked Potentials of Multimodal Cortical Vestibular Areas: Galvanic Stimulation

    Directory of Open Access Journals (Sweden)

    Stefan Kammermeier

    2017-11-01

    Full Text Available IntroductionHuman multimodal vestibular cortical regions are bilaterally anterior insulae and posterior opercula, where characteristic vestibular-related cortical potentials were previously reported under acoustic otolith stimulation. Galvanic vestibular stimulation likely influences semicircular canals preferentially. Galvanic stimulation was compared to previously established data under acoustic stimulation.Methods14 healthy right-handed subjects, who were also included in the previous acoustic potential study, showed normal acoustic and galvanic vestibular-evoked myogenic potentials. They received 2,000 galvanic binaural bipolar stimuli for each side during EEG recording.ResultsVestibular cortical potentials were found in all 14 subjects and in the pooled data of all subjects (“grand average” bilaterally. Anterior insula and posterior operculum were activated exclusively under galvanic stimulation at 25, 35, 50, and 80 ms; frontal regions at 30 and 45 ms. Potentials at 70 ms in frontal regions and at 110 ms at all of the involved regions could also be recorded; these events were also found using acoustic stimulation in our previous study.ConclusionGalvanic semicircular canal stimulation evokes specific potentials in addition to those also found with acoustic otolith stimulation in identically located regions of the vestibular cortex. Vestibular cortical regions activate differently by galvanic and acoustic input at the peripheral sensory level.SignificanceDifferential effects in vestibular cortical-evoked potentials may see clinical use in specific vertigo disorders.

  8. Micro-electrochemical characterization of galvanic corrosion of TA2/316L composite plate

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, X.; Li, X.; Dong, C.; Xiao, K. [Corrosion and Protection Center, University of Science and Technology Beijing (China)

    2011-12-15

    Galvanic corrosion behavior of TA2/316L composite plate was investigated in the solution of 3.5 wt% NaCl by galvanic potential monitoring, scanning localized electrochemical impedance spectroscopy (LEIS) and scanning vibrating micro-electrode (SVME) techniques. The results demonstrated that the pitting corrosion resistance of 316L for the galvanic combination sample is lower, and the coupled current density is higher than for the single 316L sample. It indicates that the galvanic action works on the corrosion behavior of the TA2 titanium alloy/316L stainless steel galvanic combination in sodium chloride solution. The galvanic effect width was determined as 1500 {mu}m. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Galvanic manufacturing in the cities of Russia: potential source of ambient nanoparticles.

    Directory of Open Access Journals (Sweden)

    Kirill S Golokhvast

    Full Text Available Galvanic manufacturing is widely employed and can be found in nearly every average city in Russia. The release and accumulation of different metals (Me, depending on the technology used can be found in the vicinities of galvanic plants. Under the environmental protection act in Russia, the regulations for galvanic manufacturing do not include the regulations and safety standards for ambient ultrafine and nanosized particulate matter (PM. To assess whether Me nanoparticles (NP are among environmental pollutants caused by galvanic manufacturing, the level of Me NP were tested in urban snow samples collected around galvanic enterprises in two cities. Employing transmission electronic microscopy, energy-dispersive X-ray spectroscopy, and a laser diffraction particle size analyzer, we found that the size distribution of tested Me NP was within 10-120 nm range. This is the first study to report that Me NP of Fe, Cr, Pb, Al, Ni, Cu, and Zn were detected around galvanic shop settings.

  10. DIP and DIP + 2 as glutathione oxidants and radiation sensitizers in cultured Chinese hamster cells

    International Nuclear Information System (INIS)

    Harris, J.W.; Power, J.A.; Kosower, N.S.; Kosower, E.M.

    1975-01-01

    Two diamide analogues, diazene dicarboxylic acid bis (N'-methyl-piperazide) or DIP, and its bis-N'-methyl iodide salt, or DIP + 2, were tested for their ability to penetrate cultured Chinese hamster cells and oxidize intracellular glutathione. DIP penetrated the cells at a reasonable rate at 18 0 C, 160 nmoles being required to oxidize the endogenous glutathione of 2 x 10 6 cells, but it penetrated very slowly at 0 0 C. DIP + 2 did not effectively oxidize glutathione in Chinese hamster cells, possibly because it did not enter the cels. DIP became toxic after about 10 min of exposure, but its toxicity could be moderated by using anoxic conditions. DIP, but not DIP + 2, sensitized anoxic Chinese hamster cells to X-radiation by a factor of 1.5, an effect that was due entirely to removal of the shoulder from the survival curve. (author)

  11. 7 CFR 1755.370 - RUS specification for seven wire galvanized steel strand.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false RUS specification for seven wire galvanized steel..., ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.370 RUS specification for seven wire galvanized... Steel Wire Strand, issued May 1978. All seven wire galvanized steel strand purchased after April 1, 1990...

  12. Dips spacecraft integration issues

    International Nuclear Information System (INIS)

    Determan, W.R.; Harty, R.B.

    1988-01-01

    The Department of Energy, in cooperation with the Department of Defense, has recently initiated the dynamic isotope power system (DIPS) demonstration program. DIPS is designed to provide 1 to 10 kW of electrical power for future military spacecraft. One of the near-term missions considered as a potential application for DIPS was the boost surveillance and tracking system (BSTS). A brief review and summary of the reasons behind a selection of DIPS for BSTS-type missions is presented. Many of these are directly related to spacecraft integration issues; these issues will be reviewed in the areas of system safety, operations, survivability, reliability, and autonomy

  13. Gold recovery from organic solvents using galvanic stripping

    Energy Technology Data Exchange (ETDEWEB)

    Flores, C.; O`Keefe, T.J. [Univ. of Missouri, Rolla, MO (United States). Dept. of Metallurgical Engineering

    1995-08-01

    A novel process using solid metals for the direct reduction of more noble metal ions from solvent extraction organics has been developed. Base metals recovery has been the principal focus of investigations to date but feasibility tests have now also been made on galvanically stripping selected precious metals. In this study gold (III) was loaded from an aqueous HAuCl{sub 4}{center_dot}3H{sub 2}O solution into a mixed organic 40 vol.% TBP, 10 vol.% D2EHPA in kerosene. The direct precipitation of metallic gold from the loaded organic phase using zinc powder and iron, aluminum and copper slabs at 70 C was successfully demonstrated. The gold reduction rates were relatively fast even though the conductivity of the organic solutions is very low. The reaction rates were studied as a function of the variables zinc particulate size, oxygen and nitrogen atmosphere, water content in the organic phase, organic ratios and temperature. The gold morphology was usually powdery or dendritic in nature but continuous films were obtained in some instances. Activation energies were calculated and possible reaction mechanisms are discussed. In general, the results obtained were very promising and showed that gold can be successfully cemented from selected organic solvents by galvanic stripping using less noble solid metal reductants.

  14. 75 FR 17162 - Dipping and Coating Operations (Dip Tanks) Standard; Extension of the Office of Management and...

    Science.gov (United States)

    2010-04-05

    ...] Dipping and Coating Operations (Dip Tanks) Standard; Extension of the Office of Management and Budget's... Standard on Dipping and Coating Operations (Dip Tanks) (29 CFR 1910.126(g)(4)). DATES: Comments must be... of efforts in obtaining information (29 U.S.C. 657). The Standard on Dipping and Coating Operations...

  15. Surface Oxidation of the High-Strength Steels Electrodeposited with Cu or Fe and the Resultant Defect Formation in Their Coating during the Following Galvanizing and Galvannealing Processes

    Science.gov (United States)

    Choi, Yun-Il; Beom, Won-Jin; Park, Chan-Jin; Paik, Doojin; Hong, Moon-Hi

    2010-12-01

    This study examined the surface oxidation of high-strength steels electrodeposited with Cu or Fe and the resultant defect formation in their coating during the following galvanizing and galvannealing processes. The high-strength steels were coated with an Cu or Fe layer by the electroplating method. Then, the coated steels were annealed in a reducing atmosphere, dipped in a molten zinc, and finally transformed into galvannealed steels through the galvannealing process. The formation of Si and Mn oxides on the surface of the high-strength steel was effectively suppressed, and the density of surface defects on the galvanized steel was significantly reduced by the pre-electrodeposition of Cu and Fe. This effect was more prominent for the steels electrodeposited at higher cathodic current densities. The finer electrodeposit layer formed at higher cathodic current density on the steels enabled the suppression of partial surface oxidation by Mn or Si and better wetting of Zn on the surface of the steels in the following galvanizing process. Furthermore, the pre-electrodeposited steels exhibited a smoother surface without surface cracks after the galvannealing process compared with the untreated steel. The diffusion of Fe and Zn in the Zn coating layer in the pre-electrodeposited steels appears to occur more uniformly during the galvannealing process due to the low density of surface defects induced by oxides.

  16. UNDERSTANDING THE STRUCTURE OF THE HOT INTERSTELLAR MEDIUM IN NORMAL EARLY-TYPE GALAXIES.

    Science.gov (United States)

    Traynor, Liam; Kim, Dong-Woo; Chandra Galaxy Atlas

    2018-01-01

    The hot interstellar medium (ISM) of early-type galaxies (ETG's) provides crucial insight into the understanding of their formation and evolution. Mechanisms such as type Ia supernovae heating, AGN feedback, deepening potential depth through dark matter assembly and ramp-pressure stripping are known to affect the structure of the ISM. By using temperature maps and radial temperature profiles of the hot ISM from ~70 ETG's with archival Chandra data, it is possible to classify the galaxy's ISM into common structural types. This is extended by using 3D fitting of the radial temperature profile in order to provide models that further constrain the structural types. Five structural types are present, negative (temperature decreases with radii), positive (temperature increases with radii), hybrid-dip (temperature decreases at small radii and increases at large radii), hybrid-bump (inverse of hybrid-dip) and quasi-isothermal (temperature is constant at all radii). This work will be continued by 1) determining which mechanisms are present in which galaxies and 2) analysing the model parameters between galaxies within each structural type to determine whether each type can be described by a single set of model parameters, indicating that the same physical processes are responsible for creating that structural type.

  17. About neutralization of the toxic waste of galvanic production

    International Nuclear Information System (INIS)

    Akhmetzhanova, Z.Kh.; Samatov, I.B.

    1996-01-01

    The nature of heavy metals ions migration to environment from the galvanic production is considered in the article. The method of toxic precipitations transformation to non-toxic ones is proposed. The essence of stabilization method of heavy metals hydroxides precipitations consists in transformation of galvanic precipitations mixture to same metals ferrites mixture. The reaction has followed in oxygen medium under heating of galvanic precipitations from 70 up 90 deg C. Before heating the precipitation have acid medium, after temperature treatment the medium turn to the neutral one. These compounds are presented as ferrite class and can be serve as base for various pigments. (author)

  18. Hot deformation effect on the kinetics of austenite transformation under continuous cooling conditions

    International Nuclear Information System (INIS)

    Bernshtejn, M.L.; Zajmovskij, V.A.; Kisteh, N.V.; Samedov, O.V.; Faldin, S.A.

    1979-01-01

    The effect of hot deformation on the kinetics of austenite transformations in the commercial 4040Kh 40KhN, and 40KhNMA steels on continuous cooling was studied. The transformations were studied using a dilatometer of a special design which permits a specimen to be fixed quickly in holders after hot deformation. It is stated that in hot-deformed austenite the pearlite transformation proceeds at higher temperatures and in a narrower temperature range. Austenite deformation provides an opportunity to obtain a more fine ferrite-pearlite structure and ensures a uniform distribution of a structurally free ferrite in the steel bulk. The effect of hot deformation on the structure of ferrite decomposition products in the 40KhN and 40KhNMA steels is more complicated, which is connected with a substantial change in the kinetics of pearlite and intermediate transformations

  19. Migration using a transversely isotropic medium with symmetry normal to the reflector dip

    KAUST Repository

    Alkhalifah, Tariq Ali; Sava, P.

    2011-01-01

    A transversely isotropic (TI) model in which the tilt is constrained to be normal to the dip (DTI model) allows for simplifications in the imaging and velocity model building efforts as compared to a general TI (TTI) model. Although this model cannot be represented physically in all situations, for example, in the case of conflicting dips, it handles arbitrary reflector orientations under the assumption of symmetry axis normal to the dip. Using this assumption, we obtain efficient downward continuation algorithms compared to the general TTI ones, by utilizing the reflection features of such a model. Phase-shift migration can be easily extended to approximately handle lateral inhomogeneity using, for example, the split-step approach. This is possible because, unlike the general TTI case, the DTI model reduces to VTI for zero dip. These features enable a process in which we can extract velocity information by including tools that expose inaccuracies in the velocity model in the downward continuation process. We test this model on synthetic data corresponding to a general TTI medium and show its resilience. 2011 Tariq Alkhalifah and Paul Sava.

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

    Science.gov (United States)

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

    2002-01-01

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

  1. Migration velocity analysis using a transversely isotropic medium with tilt normal to the reflector dip

    KAUST Repository

    Alkhalifah, T.

    2010-06-13

    A transversely isotropic model in which the tilt is constrained to be normal to the dip (DTI model) allows for simplifications in the imaging and velocity model building efforts as compared to a general TTI model. Though this model, in some cases, can not be represented physically like in the case of conflicting dips, it handles all dips with the assumption of symmetry axis normal to the dip. It provides a process in which areas that meet this feature is handled properly. We use efficient downward continuation algorithms that utilizes the reflection features of such a model. For lateral inhomogeneity, phase shift migration can be easily extended to approximately handle lateral inhomogeneity, because unlike the general TTI case the DTI model reduces to VTI for zero dip. We also equip these continuation algorithms with tools that expose inaccuracies in the velocity. We test this model on synthetic data of general TTI nature and show its resilience even couping with complex models like the recently released anisotropic BP model.

  2. Galvanic detection of sulfur dioxide in ambient air at trace levels by anodic oxidation

    NARCIS (Netherlands)

    Lindqvist, F.

    1978-01-01

    A continuous method for the measurement of SO2 in ambient air at trace levels is described. The principle of detection is based on the anodic oxidation of SO2 in a galvanic cell. A differential measuring technique with a cell with two anodes and one cathode is used; background and noise current are

  3. Imposed currents in galvanic cells

    International Nuclear Information System (INIS)

    Biesheuvel, P.M.; Soestbergen, M. van; Bazant, M.Z.

    2009-01-01

    We analyze the steady-state behavior of a general mathematical model for reversible galvanic cells, such as redox flow cells, reversible solid oxide fuel cells, and rechargeable batteries. We consider not only operation in the galvanic discharging mode, spontaneously generating a positive current against an external load, but also operation in two modes which require a net input of electrical energy: (i) the electrolytic charging mode, where a negative current is imposed to generate a voltage exceeding the open-circuit voltage, and (ii) the 'super-galvanic' discharging mode, where a positive current exceeding the short-circuit current is imposed to generate a negative voltage. Analysis of the various (dis-)charging modes of galvanic cells is important to predict the efficiency of electrical to chemical energy conversion and to provide sensitive tests for experimental validation of fuel cell models. In the model, we consider effects of diffuse charge on electrochemical charge-transfer rates by combining a generalized Frumkin-Butler-Volmer equation for reaction kinetics across the compact Stern layer with the full Poisson-Nernst-Planck transport theory, without assuming local electroneutrality. Since this approach is rare in the literature, we provide a brief historical review. To illustrate the general theory, we present results for a monovalent binary electrolyte, consisting of cations, which react at the electrodes, and non-reactive anions, which are either fixed in space (as in a solid electrolyte) or are mobile (as in a liquid electrolyte). The full model is solved numerically and compared to analytical results in the limit of thin diffuse layers, relative to the membrane thickness. The spatial profiles of the ion concentrations and electrostatic potential reveal a complex dependence on the kinetic parameters and the imposed current, in which the diffuse charge at each electrode and the total membrane charge can have either sign, contrary perhaps to intuition

  4. Alexander von Humboldt: galvanism, animal electricity, and self-experimentation part 1: formative years, naturphilosophie, and galvanism.

    Science.gov (United States)

    Finger, Stanley; Piccolino, Marco; Stahnisch, Frank W

    2013-01-01

    During the 1790s, Alexander von Humboldt (1769-1859), who showed an early interest in many facets of natural philosophy and natural history, delved into the controversial subject of galvanism and animal electricity, hoping to shed light on the basic nature of the nerve force. He was motivated by his broad worldview, the experiments of Luigi Galvani, who favored animal electricity in more than a few specialized fishes, and the thinking of Alessandro Volta, who accepted specialized fish electricity but was not willing to generalize to other animals, thinking Galvani's frog experiments flawed by his use of metals. Differing from many German Naturphilosophen, who shunned "violent" experiments, the newest instruments, and detailed measurement, Humboldt conducted thousands of galvanic experiments on animals and animal parts, as well as many on his own body, some of which caused him great pain. He interpreted his results as supporting some but not all of the claims made by both Galvani and Volta. Notably, because of certain negative findings and phenomenological differences, he remained skeptical about the intrinsic animal force being qualitatively identical to true electricity. Hence, he referred to a "galvanic force," not animal electricity, in his letters and publications, a theoretical position he would abandon with Volta's help early in the new century.

  5. 76 FR 55031 - Galvanized Steel Wire From the People's Republic of China: Preliminary Affirmative Countervailing...

    Science.gov (United States)

    2011-09-06

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-976] Galvanized Steel Wire From... galvanized steel wire (galvanized wire) from the People's Republic of China (PRC). For information on the..., filed in proper form, concerning imports of galvanized wire from the PRC.\\1\\ The Department initiated a...

  6. Tolerance to extended galvanic vestibular stimulation: optimal exposure for astronaut training.

    Science.gov (United States)

    Dilda, Valentina; MacDougall, Hamish G; Moore, Steven T

    2011-08-01

    We have developed an analogue of postflight sensorimotor dysfunction in astronauts using pseudorandom galvanic vestibular stimulation (GVS). To date there has been no study of the effects of extended GVS on human subjects and our aim was to determine optimal exposure for astronaut training based on tolerance to intermittent and continuous galvanic stimulation. There were 60 subjects who were exposed to a total of 10.5 min of intermittent GVS at a peak current of 3.5 mA or 5 mA. A subset of 24 subjects who tolerated the intermittent stimulus were subsequently exposed to 20-min continuous stimulation at 3.5 mA or 5 mA. During intermittent GVS the large majority of subjects (78.3%) reported no or at most mild motion sickness symptoms, 13.3% reported moderate symptoms, and 8.3% experienced severe nausea and requested termination of the stimulus. During 20-min continuous exposure, 83.3% of subjects reported no or at most mild motion sickness symptoms and 16.7% (all in the 5-mA group) experienced severe nausea. Based on these results, we propose two basic modes of GVS application to minimize the incidence of motion sickness: intermittent high (5 mA) amplitude, suited to simulation of intensive operator tasks requiring a high-fidelity analogue of postflight sensorimotor dysfunction such as landing or docking maneuvers; and continuous low (3.5 mA) amplitude stimulation, for longer simulation scenarios such as extra vehicular activity. Our results suggest that neither mode of stimulation would induce motion sickness in the large majority of subjects for up to 20 min exposure.

  7. DIPS space exploration initiative safety

    International Nuclear Information System (INIS)

    Dix, T.E.

    1991-01-01

    The Dynamic Isotope Power Subsystem has been identified for potential applications for the Space Exploration Initiative. A qualitative safety assessment has been performed to demonstrate the overall safety adequacy of the Dynamic Isotope Power Subsystem for these applications. Mission profiles were defined for reference lunar and martian flights. Accident scenarios were qualitatively defined for all mission phases. Safety issues were then identified. The safety issues included radiation exposure, fuel containment, criticality, diversion, toxic materials, heat flux to the extravehicular mobility unit, and disposal. The design was reviewed for areas where safety might be further improved. Safety would be improved by launching the fuel separate from the rest of the subsystem on expendable launch vehicles, using a fuel handling tool during unloading of the hot fuel canister, and constructing a cage-like structure around the reversible heat removal system lithium heat pipes. The results of the safety assessment indicate that the DIPS design with minor modifications will produce a low risk concept

  8. Review of Langmuir-Wave-Caused Dips and Charge-Exchange-Caused Dips in Spectral Lines from Plasmas and their Applications

    Directory of Open Access Journals (Sweden)

    Elisabeth Dalimier

    2014-05-01

    Full Text Available We review studies of two kinds of dips in spectral line profiles emitted by plasmas—dips that have been predicted theoretically and observed experimentally: Langmuir-wave-caused dips (L-dips and charge-exchange-caused dips (X-dips. There is a principal difference with respect to positions of L-dips and X-dips relative to the unperturbed wavelength of a spectral line: positions of L-dips scale with the electron density Ne roughly as Ne1/2, while positions of X-dips are almost independent of Ne (the dependence is much weaker than for L-dips. L-dips and X-dips phenomena are important, both fundamentally and practically. The fundamental importance is due to a rich physics behind each of these phenomena. L-dips are a multi-frequency resonance phenomenon caused by a single-frequency (monochromatic electric field. X-dips are due to charge exchange at anticrossings of terms of a diatomic quasi-molecule, whose nuclei have different charges. As for important practical applications, they are as follows: observations of L-dips constitute a very accurate method to measure the electron density in plasmas—a method that does not require knowledge of the electron temperature. L-dips also allow measuring the amplitude of the electric field of Langmuir waves—the only spectroscopic method available for this purpose. Observations of X-dips provide an opportunity to determine rate coefficient of charge exchange between multi-charged ions. This is an important reference data, virtually inaccessible by other experimental methods. The rate coefficients of charge exchange are important for magnetic fusion in Tokamaks, for population inversion in the soft x-ray and VUV ranges, for ion storage devices, as well as for astrophysics (e.g., for the solar plasma and for determining the physical state of planetary nebulae.

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

    International Nuclear Information System (INIS)

    Kim, Dong Jin; Kim, Hong Pyo; Kim, Joung Soo; Machonald, Digby D.

    2005-01-01

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

  10. DFT study on the galvanic interaction between pyrite (100) and galena (100) surfaces

    International Nuclear Information System (INIS)

    Ke, Baolin; Li, Yuqiong; Chen, Jianhua; Zhao, Cuihua; Chen, Ye

    2016-01-01

    Graphical abstract: - Highlights: • Galvanic interaction is weakened with the increase of contact distance. • Electronic transfer mainly occurs on the contact layers. • Galvanic effect enhances nucleophilicity of galena and electrophilicity of pyrite. • Presence of H_2O increases the galvanic interaction. - Abstract: The galvanic interaction between pyrite and galena surface has been investigated using density functional theory (DFT) method. The calculated results show that galvanic interactions between pyrite and galena surface are decreased with the increase of contact distance. The galvanic interactions still occurs even the distance larger than the sum of two atoms radius (≈2.8 Å), and the limit distance of galvanic interaction between galena and pyrite surface is about 10 Å, which is consistent with the quantum tunneling effect. Through Mulliken charge population calculation, it is found that electrons transfer from galena to pyrite. For galena surface, Pb 6s and 6p states lose electrons and S 3p state loses a small amount of electrons, which causes the electron loss of galena. For pyrite surface, Fe 4p state obtains large numbers of electrons, resulting in the decrease of positive charge of Fe atom. However, the 3p state of S atom loses a small numbers of electrons. The reactivity of mineral surface has also been studied by calculating the frontier orbitals of minerals. Results suggest that the highest occupied molecular orbital (HOMO) coefficients of galena are increased whereas those of pyrite are decreased with the enhancing galvanic interaction, indicating that the oxidation of galena surface would be enhanced due to the galvanic interaction. The Fukui indices and dual descriptor values of surface atoms suggest that the nucleophilicity of the galena surface increases, meanwhile, the electrophilicity of pyrite surface increases with the decrease of the contact distance. In addition, the density of states (DOS) of atoms results show that the

  11. Performance of Inductors Attached to a Galvanizing Bath

    Science.gov (United States)

    Zhou, Xinping; Yuan, Shuo; Liu, Chi; Yang, Peng; Qian, Chaoqun; Song, Bao

    2013-12-01

    By taking a galvanizing bath with inductors from an Iron and Steel Co., Ltd as an example, the distributions of Lorentz force and generated heat in the inductor are simulated. As a result, the zinc flow and the temperature distribution driven by the Lorentz force and the generated heat in the inductor of a galvanizing bath are simulated numerically, and their characteristics are analyzed. The relationship of the surface-weighted average velocity at the outlet and the temperature difference between the inlet and the outlet and the effective power for the inductor is studied. Results show that with an increase in effective power for the inductor, the surface-weighted average velocity at the outlet and the temperature difference between the inlet and the outlet increase gradually. We envisage this work to lay a foundation for the study of the performance of the galvanizing bath in future.

  12. Vertical Soil Profiling Using a Galvanic Contact Resistivity Scanning Approach

    Directory of Open Access Journals (Sweden)

    Luan Pan

    2014-07-01

    Full Text Available Proximal sensing of soil electromagnetic properties is widely used to map spatial land heterogeneity. The mapping instruments use galvanic contact, capacitive coupling or electromagnetic induction. Regardless of the type of instrument, the geometrical configuration between signal transmitting and receiving elements typically defines the shape of the depth response function. To assess vertical soil profiles, many modern instruments use multiple transmitter-receiver pairs. Alternatively, vertical electrical sounding can be used to measure changes in apparent soil electrical conductivity with depth at a specific location. This paper examines the possibility for the assessment of soil profiles using a dynamic surface galvanic contact resistivity scanning approach, with transmitting and receiving electrodes configured in an equatorial dipole-dipole array. An automated scanner system was developed and tested in agricultural fields with different soil profiles. While operating in the field, the distance between current injecting and measuring pairs of rolling electrodes was varied continuously from 40 to 190 cm. The preliminary evaluation included a comparison of scan results from 20 locations to shallow (less than 1.2 m deep soil profiles and to a two-layer soil profile model defined using an electromagnetic induction instrument.

  13. Ultrasonic dip seal maintenance system

    International Nuclear Information System (INIS)

    Poindexter, A.M.; Ricks, H.E.

    1978-01-01

    Disclosed is a system for removing impurities from the surfaces of liquid dip seals and for wetting the metal surfaces of liquid dip seals in nuclear components. The system comprises an ultrasonic transducer that transmits ultrasonic vibrations along an ultrasonic probe to the metal and liquid surfaces of the dip seal thereby loosening and removing those impurities

  14. 77 FR 17418 - Galvanized Steel Wire From the People's Republic of China: Final Affirmative Countervailing Duty...

    Science.gov (United States)

    2012-03-26

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-976] Galvanized Steel Wire From... exporters of galvanized steel wire (galvanized wire) from the People's Republic of China (the PRC). For... three parties withdrew their requests for a hearing. \\1\\ See Galvanized Steel Wire From the People's...

  15. Galvanic corrosion evaluation of high activity nuclear waste container metals components

    International Nuclear Information System (INIS)

    Semino, C.J.

    1990-04-01

    The final disposal container for vitrified high-level waste is assumed to have three metallic layers: a stainless steel inner layer, and external one of a metal to be selected and a thick lead layer (10 cm) in the middle. As design limit, the container shall act as an engineering barrier, granting the isolation of the radionuclides for approximately 1000 years. Preliminary titanium-lead galvanic couple tests showed that titanium behaved always as a cathode in the galvanic couple, promoting the galvanic corrosion of lead. This corrosion study focused on the behaviour of lead-AISI 304 stainless steel and lead-carbon steel (SAE 1010 and 1020) galvanic couples with different area relationships, temperature and media composition. High purity lead (99,999%) and commercial lead (99,9%) were used for galvanic couples tests. Tests were performed at 75, 50, 45 and 40 deg. C. Test solution was either synthetic groundwater, a suspension of 10% bentonite in groundwater, or synthetic sea water. The synthetic sea water was used at 100, 50 and 25% concentration by dilution with distilled water. Tests with lead-304 stainless steel galvanic couples showed that lead always behaves as an anode, corroding preferentially. Very low lead corrosion rates were found in lead-carbon steel galvanic couple in 10% bentonite suspension in synthetic groundwater test at 75 deg. C. An increase of carbon content in steel has very little influence on steel corrosion rate. Commercial lead has a higher corrosion rate and presented a more pronounced attack than high purity lead. Its corrosion rate is at least twice when lead-carbon steel area relationship increases from 1:10 to 1:40. There are higher steel corrosion rates in sea water than in groundwater. Lead behaves as a cathode to the end of the test. 8 refs, 85 figs, 10 tabs

  16. Opto-galvanic effect on degenerate magnetic states of sputtered atoms in a glow discharge

    International Nuclear Information System (INIS)

    Zhechev, D; Steflekova, V

    2014-01-01

    The opto-galvanic response of some degenerate states of sputtered atoms to linearly- and circularly polarize light is studied. On the same optical transition both time-resolved- and amplitude opto-galvanic signals are found depending on the polarizations of light absorbed. The latter induces galvanic responses differing in opto-galvanic efficiency, time-evolution and sensitivity to discharge current and laser power. The differences are ascribed to the rate constants of the decay processes, characterizing aligned and oriented atoms

  17. Galvanic coupling of steel and gold alloy lingual brackets with orthodontic wires.

    Science.gov (United States)

    Polychronis, Georgios; Al Jabbari, Youssef S; Eliades, Theodore; Zinelis, Spiros

    2018-03-06

    The aim of this research was to assess galvanic behavior of lingual orthodontic brackets coupled with representative types of orthodontic wires. Three types of lingual brackets: Incognito (INC), In-Ovation L (IOV), and STb (STB) were combined with a stainless steel (SS) and a nickel-titanium (NiTi) orthodontic archwire. All materials were initially investigated by scanning electron microscopy / x-ray energy dispersive spectroscopy (SEM/EDX) while wires were also tested by x-ray diffraction spectroscopy (XRD). All bracket-wire combinations were immersed in acidic 0.1M NaCl 0.1M lactic acid and neutral NaF 0.3% (wt) electrolyte, and the potential differences were continuously recorded for 48 hours. The SEM/EDX analysis revealed that INC is a single-unit bracket made of a high gold (Au) alloy while IOV and STB are two-piece appliances in which the base and wing are made of SS alloys. The SS wire demonstrated austenite and martensite iron phase, while NiTi wire illustrated an intense austenite crystallographic structure with limited martensite. All bracket wire combinations showed potential differences below the threshold of galvanic corrosion (200 mV) except for INC and STB coupled with NiTi wire in NaF media. The electrochemical results indicate that all brackets tested demonstrated galvanic compatibility with SS wire, but fluoride treatment should be used cautiously with NiTi wires coupled with Au and SS brackets.

  18. Research on Forming Mechanisms and Controlling Measurements for Surface Light Spot Defects of Galvanizing Steel Coils for Automobile Use

    Science.gov (United States)

    Guangmin, Wei; Haiyan, Sun; Jianqiang, Shi; Lianxuan, Wang; Haihong, Wu

    When producing high surface quality galvanizing steel coils for automobile use, there are always many light spots on the surface since Hansteel CGL No.1 has been put into operation. The defect samples were analyzed by SEM and EDS. The result shows that cause for light spot is not only one. There are more Mn and P in high strength auto sheet, which can result in difficulty to be cleaned off the oxide on the hot rolled coils, so the defects coming. This is why the defects come with high strength auto sheet. When coils galvanized, the defects can't be covered up. To the contrary, the defects will be more obvious when zinc growing on the surface. And sometimes zinc or residue can adhere to work rolls when strips passing through SPM. The deposits then press normal coating. So the light spots come more. When the defect comes from pressing, there is no defect on steel base. The causation is found and measures were taken including high pressure cleaning equipments adopted. Result shows that the defects disappeared.

  19. Galvanic corrosion of metals and coatings when coupled to uranium in severe environments

    International Nuclear Information System (INIS)

    Winkle, J.R.; Childs, E.L.

    1982-01-01

    The results of galvanic testing were varied in each environment. The position of metals in the galvanic series was not fixed, but changed with environment. In all cases where high general and galvanic corrosion rates were observed, the conditions of potential, pH, and impurity content could be correlated with regions of oxide surface film instability outlined by Pourbaix Diagrams. The majority of the severe corrosion reactions were observed in the acidic environment, although a few were noted in the caustic environment. The presence of chlorides tended to enhance galvanic corrosion rates at the neutral environment. 10 tables

  20. Effect of galvanic coupling between overpack materials for high-level nuclear waste containers

    International Nuclear Information System (INIS)

    Dunn, D.S.; Cragnolino, G.A.; Sridhar, N.

    1998-01-01

    The effect of environmental parameters and area ratio on the galvanic protection of Alloy 825 by A516 steel was studied. A simplified model was used to calculate the potential and corrosion current density of the bimetallic couple as a function of the galvanic coupling efficiency. Galvanic corrosion tests were performed to gain confidence in the calculated values. Both the calculations and laboratory testing indicate that, with highly efficient coupling, the potential of the galvanic couple is maintained below the repassivation potential for Alloy 825 in chloride-containing solutions. As a result, the initiation of localized corrosion on Alloy 825 is prevented. The formation of oxides, scales, and corrosion product layers between the barriers is shown to reduce the efficiency of the galvanic couple, which may result in conditions under which the localized corrosion of the inner corrosion resistant barrier can occur

  1. Corrosive microenvironments at lead solder surfaces arising from galvanic corrosion with copper pipe.

    Science.gov (United States)

    Nguyen, Caroline K; Stone, Kendall R; Dudi, Abhijeet; Edwards, Marc A

    2010-09-15

    As stagnant water contacts copper pipe and lead solder (simulated soldered joints), a corrosion cell is formed between the metals in solder (Pb, Sn) and the copper. If the resulting galvanic current exceeds about 2 μA/cm(2), a highly corrosive microenvironment can form at the solder surface, with pH chloride concentrations at least 11 times higher than bulk water levels. Waters with relatively high chloride tend to sustain high galvanic currents, preventing passivation of the solder surface, and contributing to lead contamination of potable water supplies. The total mass of lead corroded was consistent with predictions based on the galvanic current, and lead leaching to water was correlated with galvanic current. If the concentration of sulfate in the water increased relative to chloride, galvanic currents and associated lead contamination could be greatly reduced, and solder surfaces were readily passivated.

  2. Shaping optimal zinc coating on the surface of high-quality ductile iron casting. Part II – Technological formula and value of diffusion coefficient

    Directory of Open Access Journals (Sweden)

    Kopyciński D.

    2017-03-01

    Full Text Available The completed research presented in the first part of the article has allowed linking the manufacturing technology of ductile iron castings with the process of hot dip galvanizing. On the basis of these data simulations were carried out to examine the behaviour of zinc diffusion coefficient D in the galvanized coating. The adopted model of zinc coating growth helped to explain the cases of excessive growth of the intermetallic phases in this type of coating. The paper analyzes covered the relationship between the roughness and phase composition of the top layer of product and the thickness and kinetics of zinc coating growth referred to individual sub-layers of the intermetallic phases.Roughness and phase composition in the surface layer of product were next related to the diffusion coefficient D examined in respective sublayers of the intermetallic phases.

  3. Modelling of hot air chamber designs of a continuous flow grain dryer

    DEFF Research Database (Denmark)

    Kjær, Lotte Strange; Poulsen, Mathias; Sørensen, Kim

    2018-01-01

    The pressure loss, flow distribution and temperature distribution of a number of designs of the hot air chamber in a continuous flow grain dryer, were investigated using CFD. The flow in the dryer was considered as steady state, compressible and turbulent. It is essential that the grain...... is uniformly dried as uneven drying can result in damage to the end-product during storage. The original commercial design was modified with new guide vanes at the inlets to reduce the pressure loss and to ensure a uniform flow to the line burner in the hot air chamber. The new guide vane design resulted...... in a 10% reduction in pressure loss and a γ-value of 0.804. Various design changes of the hot air chamber were analysed in terms of pressure loss and temperature distribution with the aim of a temperature variation of 5 K at the outlet ducts. An obstruction design was analysed, which improved mixing...

  4. Formal concept analysis applied to the prediction of additives for galvanizing process

    Directory of Open Access Journals (Sweden)

    J. Klimeš

    2010-04-01

    Full Text Available Formal concept analysis is a new mathematical approach to data analysis, data mining and to discavering patterns in data. The result of the application of the formal concept analysis method to the behavior of the galvanizing of rimmed steel is presented. Effects of additives in the galvanizing process have been correlated to the chemical element properties of the additives. This model may also help to design new alloys as additives in the galvanizing process.

  5. Galvanic corrosion of laser weldments of AA6061 aluminium alloy

    International Nuclear Information System (INIS)

    Rahman, A.B.M. Mujibur; Kumar, S.; Gerson, A.R.

    2007-01-01

    Galvanic corrosion of laser welded AA6061 aluminium alloy, arising from the varying rest potentials of the various weldment regions, was examined. The weld fusion zone is found to be the most cathodic region of the weldment while the base material is the most anodic region. The rate of galvanic corrosion, controlled by the cathodic process at the weld fusion zone, increases with time until a steady state maximum is reached. On galvanic corrosion the corrosion potential of the weld fusion zone shifts in the positive direction and the free corrosion current increases. It is proposed that the cathodic process at the weld fusion zone causes a local increase in pH that in turn causes dissolution of the surface film resulting in the loss of Al to solution and the increase of intermetallic phases. The increase in galvanic corrosion may result from either the build up of the intermetallic phases in the surface layer and/or significant increase in surface area of the weld fusion zone due to the porous nature of the surface layer

  6. 76 FR 68422 - Galvanized Steel Wire From Mexico: Preliminary Determination of Sales at Less Than Fair Value and...

    Science.gov (United States)

    2011-11-04

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-201-840] Galvanized Steel Wire From... determines that galvanized steel wire (galvanized wire) from Mexico is being, or is likely to be, sold in the... investigation on galvanized wire from Mexico. See Galvanized Steel Wire from the People's Republic of China and...

  7. Alexander von Humboldt: galvanism, animal electricity, and self-experimentation part 2: the electric eel, animal electricity, and later years.

    Science.gov (United States)

    Finger, Stanley; Piccolino, Marco; Stahnisch, Frank W

    2013-01-01

    After extensive experimentation during the 1790s, Alexander von Humboldt remained skeptical about "animal electricity" (and metallic electricity), writing instead about an ill-defined galvanic force. With his worldview and wishing to learn more, he studied electric eels in South America just as the new century began, again using his body as a scientific instrument in many of his experiments. As had been the case in the past and for many of the same reasons, some of his findings with the electric eel (and soon after, Italian torpedoes) seemed to argue against biological electricity. But he no longer used galvanic terminology when describing his electric fish experiments. The fact that he now wrote about animal electricity rather than a different "galvanic" force owed much to Alessandro Volta, who had come forth with his "pile" (battery) for multipling the physical and perceptable effects of otherwise weak electricity in 1800, while Humboldt was deep in South America. Humboldt probably read about and saw voltaic batteries in the United States in 1804, but the time he spent with Volta in 1805 was probably more significant in his conversion from a galvanic to an electrical framework for understanding nerve and muscle physiology. Although he did not continue his animal electricity research program after this time, Humboldt retained his worldview of a unified nature and continued to believe in intrinsic animal electricity. He also served as a patron to some of the most important figures in the new field of electrophysiology (e.g., Hermann Helmholtz and Emil du Bois-Reymond), helping to take the research that he had participated in to the next level.

  8. 76 FR 33242 - Galvanized Steel Wire From the People's Republic of China: Postponement of Preliminary...

    Science.gov (United States)

    2011-06-08

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-976] Galvanized Steel Wire From... the countervailing duty investigation of galvanized steel wire from the People's Republic of China. See Galvanized Steel Wire From the People's Republic of China: Initiation of Countervailing Duty...

  9. Standard guide for conducting and evaluating galvanic corrosion tests in electrolytes

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1981-01-01

    1.1 This guide covers conducting and evaluating galvanic corrosion tests to characterize the behavior of two dissimilar metals in electrical contact in an electrolyte under low-flow conditions. It can be adapted to wrought or cast metals and alloys. 1.2 This guide covers the selection of materials, specimen preparation, test environment, method of exposure, and method for evaluating the results to characterize the behavior of galvanic couples in an electrolyte. Note 1—Additional information on galvanic corrosion testing and examples of the conduct and evaluation of galvanic corrosion tests in electrolytes are given in Refs (1) through (7). 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicabil...

  10. A study on the flow-accelerated corrosion characteristics of galvanically coupled dissimilar metals

    International Nuclear Information System (INIS)

    Choi, Yoon Seok; Kim, Jung Gu

    2002-01-01

    The flow-accelerated corrosion characteristics of a carbon steel(CS) coupled to stainless steel(SS) were investigated in deaerated alkaline-chloride solutions with velocities (0, 0.2, 0.4 and 0.6 m/s), pH (8, 9 and 10) and temperatures (25, 50 and 75 .deg. C). The electrochemical properties of specimens were investigated by potentiodynamic test and galvanic corrosion test using RCE (Rotating Cylinder Electrode). CS did not show passive behavior while SS show passive behavior in the alkaline-chloride solution. Galvanic corrosion tests were conducted as a function of flow velocities, pH and temperature. The galvanic current density increases with increasing flow velocity and temperature, but decreased with increasing pH. Flow velocity had a small effect on the galvanic current density at 25 .deg. C, whereas the flow velocity increased galvanic current density significantly at 50 and 75 .deg. C. This might be due to the increased solubility of magnetite at the higher temperature

  11. Photocatalytic activity of galvanically synthesized nanostructure SnO{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jana, Sumanta, E-mail: sumantajana85@gmail.com [Department of Chemistry, Bengal Engineering and Science University, Botanic Garden, Howrah 711103, WB (India); Mitra, Bibhas Chandra [Department of Physics, Bengal Engineering and Science University, Botanic Garden, Howrah 711103, WB (India); Bera, Pulakesh [Department of Chemistry, Panskura Banamali College, Purba Medinipur, Panskura 721152, WB (India); Sikdar, Moushumi [Department of Chemistry, Bengal Engineering and Science University, Botanic Garden, Howrah 711103, WB (India); Mondal, Anup, E-mail: anupmondal2000@yahoo.co.in [Department of Chemistry, Bengal Engineering and Science University, Botanic Garden, Howrah 711103, WB (India)

    2014-07-25

    Graphical abstract: Nanostructured porous tin dioxide (SnO{sub 2}) thin films have been synthesized by simple and cost effective galvanic technique. The synthesized porous SnO{sub 2} thin films show excellent photocatalytic activity for degrading methyl orange (MO) dye under light irradiation. The porous morphological grain growth due to annealing is likely to play an active role for this degradation. - Highlights: • SnO{sub 2} thin films have been successfully synthesized by galvanic technique. • A drastic morphological change occurs after annealing as deposited SnO{sub 2} thin films. • Morphological advantage results enhanced photodegradation of dye. - Abstract: The study demonstrates an approach to synthesize nanostructure SnO{sub 2} thin films on TCO (transparent conducting oxide) coated glass substrates by galvanic technique. Aqueous solution of hydrated stannic chloride (SnCl{sub 4}⋅5H{sub 2}O) in potassium nitrate (KNO{sub 3}) solution was used as the working solution. The process involves no sophisticated reactor or toxic chemicals, and proceeds continuously under ambient condition; it provides an economic way of synthesizing nanostructure SnO{sub 2} semiconductor thin films. The influence of sintering temperature on crystalline structure, morphology, electrical and dielectric properties has been studied. A detail analysis of I−V, C−V and dielectrics for annealed SnO{sub 2} thin films have been carried out. The morphological advantage i.e. nanoporous flake like structure allows more efficient transport of reactant molecules to the active interfaces and results a strong photocatalytic activity for degrading methyl orange (MO) dye.

  12. Effects of supporting electrolyte on galvanic deposition of Cu2O crystals

    International Nuclear Information System (INIS)

    Wang Lida; Liu Guichang; Xue Dongfeng

    2011-01-01

    Highlights: → The effects of electrolyte on the galvanic deposition of Cu 2 O crystals have been investigated. → The chemical nature of supporting electrolyte plays important roles in the galvanic deposition of Cu 2 O crystals. → Cubic Cu 2 O crystals are formed in chloride electrolytes. → Truncated octahedral Cu 2 O crystals are produced in nitrate, sulfate and fluoride electrolytes. - Abstract: The effects of introduced supporting electrolyte on the galvanic deposition of Cu 2 O crystals have been investigated using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray diffraction (XRD). The results show that the chemical nature of supporting electrolytes plays very important roles in the galvanic deposition of Cu 2 O crystals. The chloride stabilizes the (1 0 0) planes of Cu 2 O crystals, resulting in the formation of cubic crystals, while nitrate, sulfate and fluoride stabilize the (1 1 1) planes of Cu 2 O crystals, leading to the deposition of truncated octahedral and octahedral Cu 2 O crystals. It provides a facile way to control the morphology of galvanically obtained Cu 2 O crystals by indirectly adjusting the inorganic adsorption agents.

  13. 9 CFR 72.25 - Dipping methods.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Dipping methods. 72.25 Section 72.25 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE... CATTLE § 72.25 Dipping methods. Dipping is accomplished by thoroughly wetting the entire skin by either...

  14. Caracterización de residuos sólidos procedentes de dos procesos distintos de galvanizado en caliente por inmersión

    Directory of Open Access Journals (Sweden)

    Delvasto, P.

    2012-02-01

    Full Text Available Zinc dust and zinc ash from hot-dip galvanizing industries located in Venezuela were characterized using atomic spectroscopy, scanning electron microscopy, X-Ray diffraction and infrared spectroscopy. Dust was formed during the high-pressure drying process of the galvanized pieces, in a plant that uses a steel kettle to hold the molten zinc. Ash identified as “A” came from the same plant as the dust, while ash identified as “B” came from a hot-dip galvanizing plant which use a ceramic lined galvanizing furnace. Dust contained 98 wt % Zn, in metallic form. Both ash samples contained: Zn and ZnO, while Zn5(OH8Cl2—H2O and ZnCl2 were only found in ash “B”. Globally, ash “A” and ash “B” contain 71 and 75 wt % Zn, respectively.

    Se caracterizaron polvos y escorias de zinc de industrias venezolanas de galvanizado en caliente por inmersión empleando espectroscopía atómica, microscopía electrónica de barrido, difracción de R-X y espectroscopía infrarroja. Los polvos se obtienen del proceso de secado a alta presión de las piezas en una planta cuyo proceso se basa en una cuba de acero para contener el zinc fundido, planta de la cual procede también la muestra de escoria denominada “A”. Por su parte, la escoria denominada “B” se genera en una industria que utiliza una cuba recubierta con refractario cerámico. Los polvos contienen 98 % en peso de zinc, en forma metálica. Las escorias, por su parte, presentaron las siguientes fases: Zn y ZnO,. Adicionalmente, la escoria “B” mostró la presencia ZnCl2 y Zn5(OH8Cl2—H2O. El contenido total de zinc (% en peso en la escoria “A” es 71 %, mientras que en la escoria “B” es 75 %.

  15. Surface investigation and tribological mechanism of a sulfate-based lubricant deposited on zinc-coated steel sheets

    Energy Technology Data Exchange (ETDEWEB)

    Timma, Christian, E-mail: christian.timma@thyssenkrupp.com [ThyssenKrupp Steel Europe AG, Technology & Innovation, Kaiser-Wilhelm Str. 100, 47166 Duisburg (Germany); University of Duisburg-Essen, Faculty of Chemistry, CENIDE, Universitätsstraße 7, 45141 Essen (Germany); Lostak, Thomas; Janssen, Stella; Flock, Jörg [ThyssenKrupp Steel Europe AG, Technology & Innovation, Kaiser-Wilhelm Str. 100, 47166 Duisburg (Germany); Mayer, Christian [University of Duisburg-Essen, Faculty of Chemistry, CENIDE, Universitätsstraße 7, 45141 Essen (Germany)

    2016-12-30

    Highlights: • Skin-passed hot-dip galvanized (HDG-) steel sheets were coated with (NH{sub 4}){sub 2}SO{sub 4} in a common roll-coating method. • A formation of (NH{sub 4}){sub 2}Zn(SO{sub 4}) * xH{sub 2}O was observed and the reaction mainly occurred in the skin-passed areas of the surface. • Sulfate coated samples reveal a superior friction behaviour in oil-like conditions compared non-sulfated specimen. - Abstract: Phosphatation is a well-known technique to improve friction and wear behaviour of zinc coated steel, but has a variety of economic and ecologic limitations. In this study an alternative coating based on ammonium sulfate ((NH{sub 4}){sub 2}SO{sub 4}) is applied on skin-passed hot-dip galvanized steel sheets in order to investigate its surface chemical and tribological behaviour in a Pin-on-Disk Tribometer. Raman- and X-ray photoelectron spectroscopic results revealed a formation of ammonium zinc sulfate ((NH{sub 4}){sub 2}Zn(SO{sub 4}){sub 2} * xH{sub 2}O) on the surface, which is primarily located in the skin-passed areas of the steel material. Sulfate coated samples exhibited a superior friction behaviour in Pin-on-Disk Tests using squalane as a model substance for oil-like lubricated conditions and a formation of a thin lubrication film is obtained in the wear track. Squalane acts as a carrier substance for ammonium zinc sulfate, leading to an effective lubrication film in the wear track.

  16. Thin film galvanic cell with RbAg4I5 solid electrolyte

    International Nuclear Information System (INIS)

    Bodnaruk, L.I.; Danilov, A.V.; Kulinkovich, V.E.; Aleskovskij, V.B.

    1975-01-01

    In order to decrease the size and weight and to increase the specific capacity and energy of galvanic cells, some solid electrolytes in the form of thin films are proposed. The galvanic cells were prepared by a combined method: the cathodic and anodic materials (Te and Ag) were evaporated under vacuo to cover an electrolyte layer, the latter being obtained by impregnating the porous materials with RbAg 4 I 5 acetonic solution. The most specific charge curves of the galvanic cells at various current densities are given: specific energy of the samples was 0.2 to 0.7 watt-h/kg, their capacity being 0.1 to 0.2 mah. Behaviour of the cells when stored (that of Ag(RbAg 4 I 5 ) interface in particular) was investigated, namely, the effect of the storage time on the capacity and internal resistance of the galvanic cell

  17. Evaluation of treatments with hot water, chemicals and ventilated containers to reduce microbial spoilage in irradiated potatoes

    International Nuclear Information System (INIS)

    Shirsat, S.G.; Thomas, P.; Nair, P.M.

    1991-01-01

    Potatoes irradiated to control sprouting were dipped in: hot water (56°C, 5 min; 52°C, 10, 15 and 20 min); cold (25°C, 5 min) or hot (56°C, 5 min) salicylic acid (1000 and 2000 ppm); or sodium hypochlorite (0.1 and 0.2%, 5 min); or dusted with salicylic acid (1 and 2%), to try to reduce the incidence of bacterial soft rot (Erwinia sp.) during controlled temperature (10°C, 15°C) and ambient temperature (20–34°C) storage. All treatments, particularly hot water and hot salicylic acid dip, increased microbial spoilage, possibly as a result of handling damage during the treatments combined with the inhibition of wound periderm formation as a result of irradiation. Storing irradiated tubers in well ventilated containers reduced soft rot compared to storing them in sacks and after 6 months storage at 10, 15 and 20–34°C, 95, 90 and 77% respectively were healthy and marketable. (author)

  18. IMPACT OF STRAIN RATE ON MICROALLOYED STEEL SHEET BREAKING

    Directory of Open Access Journals (Sweden)

    Mária Mihaliková

    2014-08-01

    Full Text Available Strain rate is a significant external factor and its influence on material behavior in forming process is a function of its internal structure. The contribution is analysis of the impact of loading rate from 1.6 x 10-4 ms-1 to 24 ms-1 to changes in the fracture of steel sheet used for bodywork components in cars. Experiments were performed on samples taken from HC420LA grade strips produced by cold rolling and hot dip galvanizing. Material strength properties were compared based on measured values, and changes to fracture surface character were observed.

  19. Chromate conversion coatings and their current application

    Directory of Open Access Journals (Sweden)

    P. Pokorny

    2016-04-01

    Full Text Available This paper describes formation, composition and possible production technologies of application chromate coatings. Summation of common examples of applications of these coatings in corrosion protection of metals and alloys is provided. Individual chromate coatings are divided by their dominant anions either with CrVI or CrIII. Restrictions of chromate coatings with dominantly CrVI and related toxicity of hexavalent chromium is discussed in detail. In conclusion, examples of both chromium and other, alternative coatings are summed up. Application of these coatings as a protection for concrete hot-dip galvanized reinforcement is also reviewed.

  20. A microfluidic galvanic cell on a single layer of paper

    Science.gov (United States)

    Purohit, Krutarth H.; Emrani, Saina; Rodriguez, Sandra; Liaw, Shi-Shen; Pham, Linda; Galvan, Vicente; Domalaon, Kryls; Gomez, Frank A.; Haan, John L.

    2016-06-01

    Paper microfluidics is used to produce single layer galvanic and hybrid cells to produce energy that could power paper-based analytical sensors. When two aqueous streams are absorbed onto paper to establish co-laminar flow, the streams stay in contact with each other with limited mixing. The interface at which mixing occurs acts as a charge-transfer region, eliminating the need for a salt bridge. We designed a Cusbnd Zn galvanic cell that powers an LED when two are placed in series. We also used more powerful redox couples (formate and silver, formate and permanganate) to produce higher power density (18 and 3.1 mW mg-1 Pd). These power densities are greater than previously reported paper microfluidic fuel cells using formate or methanol. The single layer design is much more simplified than previous reports of multi-layer galvanic cells on paper.

  1. 76 FR 73589 - Galvanized Steel Wire From the People's Republic of China: Amended Preliminary Determination of...

    Science.gov (United States)

    2011-11-29

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-975] Galvanized Steel Wire From... galvanized steel wire from the People's Republic of China (``PRC'').\\1\\ We are amending our Preliminary... Fair Value and Postponement of Final Determination: Galvanized Steel Wire from the People's Republic of...

  2. Area effect on galvanic corrosion of condenser materials with titanium tubes in nuclear power plants

    International Nuclear Information System (INIS)

    Hwang, Seong Sik; Kim, Joung Soo; Kim, Uh Chul

    1993-01-01

    Titanium tubes have recently been used in condensers of nuclear power plants since titanium has very good corrosion resistance to seawater. However, when it is connected to Cu alloys as tube sheet materials and these Cu alloys are connected to carbon steels as water box materials, it makes significant galvanic corrosion on connected materials. It is expected from electrochemical tests that the corrosion rate of carbon steel will increase when it is galvanically coupled with Ti or Cu in sea water and the corrosion rate of Cu will increase when it is coupled with Ti, of this couple is exposed to sea water for a long time. It is also expected that the surface area ratios, R 1 (surface area of carbon steel/surface area of Ti) and R 2 (surface area of carbon steel/surface area of Cu) are very improtant for the galvanic corrosion of carbon steel and that these should not be kept to low values in order to minimize the galvanic corrosion on the carbon steel of the water box. Immersed galvanic corrosion tests show that the corrosion rate of carbon steel is 4.4 mpy when this ratio is 10 -2 . The galvanic corrosion rate of this carbon steel is increased from 4.4 mpy to 13 mpy at this area ratio, 1, when this connected galvanic specimen is galvanically coupled with a Ti tube. This can be rationalized by the combined effects of R 1 and R 2 on the polarization curve. (Author)

  3. Hydrogen embrittlement and galvanic corrosion of titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Soh, Jeong Ryong; Jeong, Y. H.; Choi, B. K.; Baek, J. H.; Hwang, D. Y.; Choi, B. S.; Lee, D. J

    2000-06-01

    The material properties including the fracture behavior of titanium alloys used as a steam generator tube in SMART can be degraded de to the hydrogen embrittlement and the galvanic corrosion occurring as a result of other materials in contact with titanium alloys in a conducting corrosive environment. In this report the general concepts and trends of hydrogen embrittlement are qualitatively described to adequately understand and expect the fracture behavior from hydrogen within the bulk of materials and under hydrogen containing environments because hydrogen embrittlement may be very complicated process. And the characteristics of galvanic corrosion closely related to hydrogen embrittlement is qualitatively based on wimple electrochemical theory.

  4. Hydrogen embrittlement and galvanic corrosion of titanium alloys

    International Nuclear Information System (INIS)

    Soh, Jeong Ryong; Jeong, Y. H.; Choi, B. K.; Baek, J. H.; Hwang, D. Y.; Choi, B. S.; Lee, D. J.

    2000-06-01

    The material properties including the fracture behavior of titanium alloys used as a steam generator tube in SMART can be degraded de to the hydrogen embrittlement and the galvanic corrosion occurring as a result of other materials in contact with titanium alloys in a conducting corrosive environment. In this report the general concepts and trends of hydrogen embrittlement are qualitatively described to adequately understand and expect the fracture behavior from hydrogen within the bulk of materials and under hydrogen containing environments because hydrogen embrittlement may be very complicated process. And the characteristics of galvanic corrosion closely related to hydrogen embrittlement is qualitatively based on wimple electrochemical theory

  5. Hot ductility of continuously cast structural steels

    International Nuclear Information System (INIS)

    Pytel, S.M.

    1995-01-01

    The objective of this investigation was to explain the hot ductility of the structural steels characterized by different amount of carbon and morphology of sulfides. Two different rolling processes were simulated under computer controlled, high temperature deformation MTS system. Results of this study show that morphology of sulfides as well as temperature and amount of deformation are responsible for level of hot ductility of the steel tested. (author)

  6. A review of hot cracking in austenitic stainless steel weldments

    International Nuclear Information System (INIS)

    Shankar, V.; Gill, T.P.S.; Mannan, S.L.; Rodriguez, P.

    1991-01-01

    The occurrence of hot cracking in austenitic stainless steel weldments is discussed with respect to its origin and metallurgical contributory factors. Of the three types of hot cracking, namely solidification cracking, liquation and ductility dip cracking, solidification cracking occurs in the interdendritic regions in weld metal while liquation and ductility dip cracking occur intergranularly in the heat-affected zone (HAZ). Segregation of impurity and minor elements such as sulphur, phosphorous, silicon, niobium, boron etc to form low melting eutectic phases has been found to be the major cause of hot cracking. Control of HAZ cracking requires minimisation of impurity elements in the base metal. In stabilized stainless steels containing niobium, higher amounts of delta-ferrite have been found necessary to prevent cracking than in unstabilized compositions. Titanium compounds have been found to cause liquation cracking in maraging steels and titanium containing stainless steels and superalloys. In nitrogen added stainless steels, cracking resistance decreases when the solidification mode changes to primary austenitic due to nitrogen addition. A review of the test methods to evaluate hot cracking behaviour showed that several external restraint and semi-self-restraint tests are available. The finger Test, WRC Fissure Bend Test, the PVR test and the Varestraint Test are described along with typical test results. Hot ductility testing to reveal HAZ cracking tendency during welding is described, which is of particular importance to stabilized stainless steels. Based on the literature, recommendations are made for welding stabilized and nitrogen added steels, indicating areas of further work. (author). 81 refs., 30 figs., 1 tab

  7. Influence of the cooling method on the structure of 55AlZn coatings

    Energy Technology Data Exchange (ETDEWEB)

    Mendala, J, E-mail: jacek.mendala@polsl.pl [Department of Materials Technology, Silesian University of Technology, Krasinskiego 8, 40-019 Katowice (Poland)

    2011-05-15

    In metallization processes, metals or metal alloys are used which have a low melting point and good anticorrosion properties. Moreover, they must form durable intermetallic compounds with iron or its alloys. The most common hot-dip metallization technology involves galvanizing, however, molten multi-component metal alloys are used as well. An addition of aluminium to the zinc bath causes an increase in corrosion resistance of the obtained coatings. The article presents results of tests of obtaining coatings by the batch hot-dip method in an 55AlZn bath. Kinetics of the coating growth in the tested alloys were determined in the changeable conditions of bath temperature, dip time and type of cooling. The structure of coatings and their phase composition were revealed. As a result of the tests performed, it has been found that an increase in total thickness of the coatings as a function of the dipping time at a constant temperature is almost of a parabolic nature, whereas an increase in the transient layer is of a linear nature. The structure was identified by the XRD analysis and the morphology of the coatings was tested by means of SEM. It has been found that the cooling process with the use of higher rates of cooling causes a size reduction of the structure in the outer layer and a reduction of thickness of both the intermediate diffusion layer and the whole coating by ca. 25 %.

  8. Mantle wedge serpentinization effects on slab dips

    Directory of Open Access Journals (Sweden)

    Eh Tan

    2017-01-01

    Full Text Available The mechanical coupling between a subducting slab and the overlying mantle wedge is an important factor in controlling the subduction dip angle and the flow in mantel wedge. This paper investigates the role of the amount of mantle serpentinization on the subduction zone evolution. With numerical thermos-mechanical models with elasto-visco-plastic rheology, we vary the thickness and depth extent of mantle serpentinization in the mantle wedge to control the degree of coupling between the slab and mantle wedge. A thin serpentinized mantle layer is required for stable subduction. For models with stable subduction, we find that the slab dip is affected by the down-dip extent and the mantle serpentinization thickness. A critical down-dip extent exists in mantle serpentinization, determined by the thickness of the overriding lithosphere. If the down-dip extent does not exceed the critical depth, the slab is partially coupled to the overriding lithosphere and has a constant dip angle regardless of the mantle serpentinization thickness. However, if the down-dip extent exceeds the critical depth, the slab and the base of the overriding lithosphere would be separated and decoupled by a thick layer of serpentinized peridotite. This allows further slab bending and results in steeper slab dip. Increasing mantle serpentinization thickness will also result in larger slab dip. We also find that with weak mantle wedge, there is no material flowing from the asthenosphere into the serpentinized mantle wedge. All of these results indicate that serpentinization is an important ingredient when studying the subduction dynamics in the mantle wedge.

  9. Stability of Retained Austenite in High-Al, Low-Si TRIP-Assisted Steels Processed via Continuous Galvanizing Heat Treatments

    Science.gov (United States)

    McDermid, J. R.; Zurob, H. S.; Bian, Y.

    2011-12-01

    Two galvanizable high-Al, low-Si transformation-induced plasticity (TRIP)-assisted steels were subjected to isothermal bainitic transformation (IBT) temperatures compatible with the continuous galvanizing (CGL) process and the kinetics of the retained austenite (RA) to martensite transformation during room temperature deformation studied as a function of heat treatment parameters. It was determined that there was a direct relationship between the rate of strain-induced transformation and optimal mechanical properties, with more gradual transformation rates being favored. The RA to martensite transformation kinetics were successfully modeled using two methodologies: (1) the strain-based model of Olsen and Cohen and (2) a simple relationship with the normalized flow stress, ( {{{σ_{{flow}} - σ_{YS} }/{σ_{YS }}}} ) . For the strain-based model, it was determined that the model parameters were a strong function of strain and alloy thermal processing history and a weak function of alloy chemistry. It was verified that the strain-based model in the present work agrees well with those derived by previous workers using TRIP-assisted steels of similar composition. It was further determined that the RA to martensite transformation kinetics for all alloys and heat treatments could be described using a simple model vs the normalized flow stress, indicating that the RA to martensite transformation is stress-induced rather than strain-induced for temperatures above the Ms^{σ }.

  10. Simulation of galvanic corrosion using boundary element method

    International Nuclear Information System (INIS)

    Zaifol Samsu; Muhamad Daud; Siti Radiah Mohd Kamaruddin; Nur Ubaidah Saidin; Abdul Aziz Mohamed; Mohd Saari Ripin; Rusni Rejab; Mohd Shariff Sattar

    2011-01-01

    Boundary element method (BEM) is a numerical technique that used for modeling infinite domain as is the case for galvanic corrosion analysis. The use of boundary element analysis system (BEASY) has allowed cathodic protection (CP) interference to be assessed in terms of the normal current density, which is directly proportional to the corrosion rate. This paper was present the analysis of the galvanic corrosion between Aluminium and Carbon Steel in natural sea water. The result of experimental was validated with computer simulation like BEASY program. Finally, it can conclude that the BEASY software is a very helpful tool for future planning before installing any structure, where it gives the possible CP interference on any nearby unprotected metallic structure. (Author)

  11. Finishes for Metals. Paintability of Galvanized Steel, Corrosion Resistance of Metallized Coatings.

    Science.gov (United States)

    Building Research Inst., Inc., Washington, DC.

    Two papers are presented. The first, "Report of the AISI Research Project on the Paintability of Galvanized Steel," was a project aimed at determining optimum procedures for painting bright-spangled galvanized sheet steel products using three classes of trade sales paints--metallic zinc-dust, portland cement-in-oil, and water base emulsion paints.…

  12. [Exposure to metal compounds in occupational galvanic processes].

    Science.gov (United States)

    Surgiewicz, Jolanta; Domański, Wojciech

    2006-01-01

    Occupational galvanic processes are provided in more than 600 small and medium enterprises in Poland. Workers who deal with galvanic coating are exposed to heavy metal compounds: tin, silver, copper and zinc. Some of them are carcinogenic, for example, hexavalent chromium compounds, nickel and cadmium compounds. Research covered several tens of workstations involved in chrome, nickel, zinc, tin, silver, copper and cadmium plating. Compounds of metals present in the air were determined: Cr, Ni, Cd, Sn, Ag--by atomic absorption spectrometry with electrothermal atomization (ET-AAS) and Zn--by atomic absorption spectrometry with flame atomization (F-AAS). The biggest metal concentrations--of silver and copper--were found at workstations of copper, brass, cadmium, nickel and chrome plating, conducted at the same time. Significant concentrations of copper were found at workstations of maintenance bathing and neutralizing of sewage. The concentrations of metals did not exceed Polish MAC values. MAC values were not exceeded for carcinogenic chromium(VI), nickel or cadmium, either. In galvanic processes there was no hazard related to single metals or their compounds, even carcinogenic ones. Combined exposure indicators for metals at each workstation did not exceed 1, either. However, if there are even small quantities of carcinogenic agents, health results should always be taken into consideration.

  13. 76 FR 47150 - Galvanized Steel Wire From the People's Republic of China and Mexico: Postponement of Preliminary...

    Science.gov (United States)

    2011-08-04

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-975, A-201-840] Galvanized Steel... in the Federal Register the initiation of the antidumping duty investigations of galvanized steel... is January 1, 2010, through December 31, 2010. See Galvanized Steel Wire From the People's Republic...

  14. Corrosion behaviour and galvanic coupling with steel of Al-based coating alternatives to electroplated cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Fasuba, O.A.; Yerokhin, A., E-mail: A.Yerokhin@sheffield.ac.uk; Matthews, A.; Leyland, A.

    2013-08-15

    The galvanic corrosion behaviour of bare steel coupled to steel with an Al–Zn flake inorganic spin coating, an Al-based slurry sprayed coating, an arc sprayed Al coating and electroplated cadmium has been investigated. The sacrificial and galvanic behaviour of the coatings was studied in 3.5 wt. % NaCl solution using open-circuit potential, potentiodynamic polarisation and electrochemical noise measurements. The coatings were characterised by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. Experimental results showed that the Al-based slurry sprayed coating exhibited an open-circuit potential closer to the steel substrate than other coatings, as well as a low corrosion current density and a more positive corrosion potential. In terms of the galvanic suitability of the investigated coatings for the steel substrate, both the Al–Zn flake inorganic spin coating and the Al-based slurry sprayed coating show low galvanic current, in comparison with the arc sprayed Al coating and electroplated cadmium. This behaviour confirms their superior cathodic protection capability and galvanic compatibility over other coatings tested. Electrochemical noise measurements provide accurate information on the coatings' galvanic behaviour, which can be complimented by the data obtained from superposition of potentiodynamic corrosion scans of the coating and bare steel, provided that the corrosion potential difference between the two materials does not exceed 300 mV. - Highlights: • Al-based slurry coating has best galvanic compatibility with steel. • Mg, Cr, P in Al-based slurry coating reinforce its corrosion resistance. • Ennoblement of Al–Zn flake coating compromises its cathodic protection. • Poor corrosion behaviour of arc sprayed Al coating caused by rough morphology. • Electrochemical noise provides adequate estimates of galvanic behaviour.

  15. Effect of dissolved oxygen, hydrazine and pH outside the crevice on the galvanic corrosion of support plate alloys

    International Nuclear Information System (INIS)

    McKubre, M.C.H.

    1985-01-01

    A study has been performed of the initial corrosion of support structure alloys in crevices of various geometries, when galvanically coupled to alloy 600. Corrosion rates were monitored continuously by measuring the galvanic current flowing in each couple, transduced by a zero impedance ammeter. Experiments were performed in a single-pass flowing electrolyte system, with AVT water pumped through alloy 600 tubing past the orifice of each crevice. Fourteen crevices were studied simultaneously in two parallel flow arms containing seven specimens each. The steady state AVT water pH/hydrazine/oxygen concentrations were controlled by microcomputer, allowing the effect of secondary water chemistry on the corrosion rate to be studied easily. Control of the crevice electrolyte composition was achieved by separately pumping electrolyte, at a low rate, directly into the crevices of the seven specimens in the lower flow arm. In addition, a high pressure syringe was used to introduce chemicals directly into the secondary or crevice electrolyte flow streams, in order to rapidly evaluate the influence of potential corrodent or corrosion control agents on the galvanic corrosion rates. Specimens were studied in the five basic geometries

  16. Two-colour dip spectroscopy of jet-cooled molecules

    Science.gov (United States)

    Ito, Mitsuo

    In optical-optical double resonance spectroscopy, the resonance transition from an intermediate state to a final state can be detected by a dip of the signal (fluorescence or ion) associated with the intermediate state. This method probing the signal of the intermediate state may be called `two-colour dip spectroscopy'. Various kinds of two-colour dip spectroscopy such as two-colour fluorescence/ion dip spectroscopy, two-colour ionization dip spectroscopy employing stimulated emission, population labelling spectroscopy and mass-selected ion dip spectroscopy with dissociation were briefly described, paying special attention to their characteristics in excitation, detection and application. They were extensively and successfully applied to jet-cooled large molecules and provided us with new useful information on the energy and dynamics of excited molecules.

  17. A Noble Approach of Process Automation in Galvanized Nut, Bolt Manufacturing Industry

    Directory of Open Access Journals (Sweden)

    Akash Samanta

    2012-05-01

    Full Text Available Corrosion costs money”, The Columbus battle institute estimates that corrosion costs Americans more than $ 220 billion annually, about 4.3% of the gross natural product [1].Now a days due to increase of pollution, the rate of corrosion is also increasing day-by-day mainly in India, so, to save the steel structures, galvanizing is the best and the simplest solution. Due to this reason galvanizing industries are increasing day-by-day since mid of 1700s.Galvanizing is a controlled metallurgical combination of zinc and steel that can provide a corrosion resistance in a wide variety of environment. In fact, the galvanized metal corrosion resistance factor can be some 70 to 80 times greater that the base metal material. Keeping in mind the importance of this industry, a noble approach of process automation in galvanized nut-bolt  manufacturing plant is presented here as nuts and bolts are the prime ingredient of any structure. In this paper the main objectives of any industry like survival, profit maximization, profit satisfying and sales growth are fulfilled. Furthermore the environmental aspects i.e. pollution control and energy saving are also considered in this paper. The whole automation process is done using programmable logic controller (PLC which has number of unique advantages like being faster, reliable, requires less maintenance and reprogrammable. The whole system has been designed and tested using GE, FANUC PLC.

  18. Corrosion Inhibition of the Galvanic Couple Copper-Carbon Steel in Reverse Osmosis Water

    Directory of Open Access Journals (Sweden)

    Irene Carrillo

    2011-01-01

    Full Text Available The purpose of this paper is to evaluate the electrochemical behaviour of corrosion inhibition of the copper-carbon steel galvanic couple (Cu-CS, exposed to reverse osmosis water (RO used for rinsing of heat exchangers for heavy duty machinery, during manufacture. Molybdate and nitrite salts were utilized to evaluate the inhibition behaviour under galvanic couple conditions. Cu-CS couple was used as working electrodes to measure open circuit potential (OCP, potentiodynamic polarization (PP, and electrochemical impedance spectroscopy (EIS. The surface conditions were characterized by scanning electron microscopy (SEM and electron dispersive X-ray spectroscopy (EDS. The most effective concentration ratio between molybdate and nitrite corrosion inhibitors was determined. The morphological study indicated molybdate deposition on the anodic sites of the galvanic couple. The design of molybdate-based corrosion inhibitor developed in the present work should be applied to control galvanic corrosion of the Cu-CS couple during cleaning in the manufacture of heat exchangers.

  19. 40 CFR 420.120 - Applicability; description of the hot coating subcategory.

    Science.gov (United States)

    2010-07-01

    ... works resulting from the operations in which steel is coated with zinc, terne metal, or other metals by the hot dip process, and those rinsing operations associated with that process. (b) The BPT and BAT... facilities achieving, during periods of normal production, zinc discharge levels more stringent than those...

  20. ICE-DIP kicks off

    CERN Multimedia

    CERN Bulletin

    2013-01-01

    Last month, Marie Curie Actions* added a new member to its ranks: ICE-DIP (the Intel-CERN European Doctorate Industrial Program). The programme held its kick-off meeting on 18-19 February in Leixlip near Dublin, Ireland, at Intel’s premises.   Building on CERN’s long-standing relationship with Intel in the CERN openlab project, ICE-DIP brings together CERN and industrial partners, Intel and Xena Networks, to train five Early Stage ICT Researchers. These researchers will be funded by the European Commission and granted a CERN Fellow contract while enrolled in the doctoral programmes at partner universities Dublin City University and National University of Ireland Maynooth. The researchers will go on extended secondments to Intel Labs Europe locations across Europe during their three-year training programme. The primary focus of the ICE-DIP researchers will be the development of techniques for acquiring and processing data that are relevant for the trigger a...

  1. Prognostic investigation of galvanic corrosion precursors in aircraft structures and their detection strategy

    Science.gov (United States)

    James, Robin; Kim, Tae Hee; Narayanan, Ram M.

    2017-04-01

    Aluminum alloys have been the dominant materials for aerospace construction in the past fifty years due to their light weight, forming and alloying, and relative low cost in comparison to titanium and composites. However, in recent years, carbon fiber reinforced polymers (CFRPs) and honeycomb materials have been used in aircrafts in the quest to attain lower weight, high temperature resistance, and better fuel efficiency. When these two materials are coupled together, the structural strength of the aircraft is unparalleled, but this comes at a price, namely galvanic corrosion. Previous experimental results have shown that when CFRP composite materials are joined with high strength aluminum alloys (AA7075-T6 or AA2024-T3), galvanic corrosion occurs at the material interfaces, and the aluminum is in greater danger of corroding, particularly since carbon and aluminum are on the opposite ends of the galvanic series. In this paper, we explore the occurrence of the recognizable precursors of galvanic corrosion when CFRP plate is coupled to an aluminum alloy using SS-304 bolts and exposed to environmental degradation, which creates significant concerns for aircraft structural reliability. The galvanic corrosion software package, BEASY, is used to simulate the growth of corrosion in the designed specimen after which a microwave non-destructive testing (NDT) technique is explored to detect corrosion defects that appear at the interface of this galvanic couple. This paper also explores a loaded waveguide technique to determine the dielectric constant of the final corrosion product at the Q-band millimeter-wave frequency range (33-50 GHz), as this can be an invaluable asset in developing early detection strategies.

  2. 76 FR 68407 - Galvanized Steel Wire From the People's Republic of China: Preliminary Determination of Sales at...

    Science.gov (United States)

    2011-11-04

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-975] Galvanized Steel Wire From... galvanized steel wire from the People's Republic of China (``PRC'') is being, or is likely to be, sold in the... concerning imports of galvanized steel wire from the PRC, filed in proper form by Davis Wire Corporation...

  3. The activation controlled galvanic corrosion of Carbon Steel/Zinc couple in deaerated stirred 0.2 N HCl

    International Nuclear Information System (INIS)

    Saeed, F. M. M.; Slaiman, Q. J. M.

    2005-01-01

    The effect of galvanic coupling of carbon steel to zinc (C.S. /Zn) in Deaerated 0.2 N HCl was studied using the multiple zero resistance technique to measure the galvanic current (Ig) and the coupling potential (Ecop,) versus time for the coupled metals. It was found that altering area ratio (AR) (Cathode/Anode) of the coupled metals and increasing temperature played an important role in the increasing corrosion rate as well as changing the galvanic factor (GF), galvanic current (Ig), and dissolution current (Id), in most of the cases. (author)

  4. Expression Patterns and Potential Biological Roles of Dip2a.

    Directory of Open Access Journals (Sweden)

    Luqing Zhang

    Full Text Available Disconnected (disco-interacting protein 2 homolog A is a member of the DIP2 protein family encoded by Dip2a gene. Dip2a expression pattern has never been systematically studied. Functions of Dip2a in embryonic development and adult are not known. To investigate Dip2a gene expression and function in embryo and adult, a Dip2a-LacZ mouse model was generated by insertion of β-Gal cDNA after Dip2a promoter using CRISPR/Cas9 technology. Dip2a-LacZ mouse was designed to be a lacZ reporter mouse as well as a Dip2a knockout mouse. Heterozygous mice were used to study endogenous Dip2a expression and homozygotes to study DIP2A-associated structure and function. LacZ staining indicated that Dip2a is broadly expressed in neuronal, reproductive and vascular tissues, as well as in heart, kidney, liver and lung. Results demonstrate that Dip2a is expressed in ectoderm-derived tissues in developing embryos. Adult tissues showed rich staining in neurons, mesenchymal, endothelial, smooth muscle cells and cardiomyocytes by cell types. The expression pattern highly overlaps with FSTL1 and supports previous report that DIP2A to be potential receptor of FSTL1 and its protective roles of cardiomyocytes. Broad and intense embryonic and adult expression of Dip2a has implied their multiple structural and physiological roles.

  5. Preventing the embrittling by hydrogen when galvanizing high-grade steel

    Energy Technology Data Exchange (ETDEWEB)

    Paatsch, W.

    1987-09-01

    Galvanic precipitation of a double layer consisting of a dull nickel layer overlaid with a brilliant zinc layer on low-alloyed high-strength steel grades leads to the forming of zinc-nickel alloy layers during the subsequent heat treatment. According to traction tests carried out on high-strength steel grades, as well as to hydrogen permeability tests, this process prevents embrittling by hydrogen which might be caused by galvanic process sequences - and creates a diffusion block at the same time. The alloy layers have an excellent corrosion resistance and temperature stability.

  6. Influence of MAO Treatment on the Galvanic Corrosion Between Aluminum Alloy and 316L Steel

    Science.gov (United States)

    Yang, Yuanhang; Gu, Yanhong; Zhang, Lei; Jiao, Xiangdong; Che, Juntie

    2017-12-01

    To slow down the galvanic corrosion of aluminum alloy and 316L stainless steel in subsea water, a micro-arc oxidation (MAO) coating was prepared on the surface of the Al alloy, and no treatment was performed on the surface of the 316L. The surface morphology of MAO-coated Al alloy was evaluated using a scanning electron microscope (SEM) before and after corrosion. A micro-hardness tester was used to measure the micro-hardness. Corrosion behaviors were evaluated by open-circuit potential (OCP), potentiodynamic polarization (PDP) and electrode impedance spectroscopy (EIS) tests in a 3.5 g/L NaCl solution. The results of PDP testing show that the corrosion potential of the MAO-coated galvanic pair was more positive than that of the uncoated galvanic pair and that the corrosion current density was smaller than that of the uncoated galvanic pair. EIS results show that the impedance of the galvanic pair increased after MAO coating. SEM images show that the corrosion damage of the uncoated Al alloy was more severe than that of the MAO-coated one, and the post-corrosion images of the surface of the 316L connected with MAO-coated Al alloy were more compact than those of the 316L connected with uncoated Al alloy. A physical model was developed to discuss the influence of MAO treatment on the galvanic corrosion process and corrosion mechanism.

  7. Galvanic corrosion of beryllium welds

    International Nuclear Information System (INIS)

    Hill, M.A.; Butt, D.P.; Lillard, R.S.

    1997-01-01

    Beryllium is difficult to weld because it is highly susceptible to cracking. The most commonly used filler metal in beryllium welds is Al-12 wt.% Si. Beryllium has been successfully welded using Al-Si filler metal with more than 30 wt.% Al. This filler creates an aluminum-rich fusion zone with a low melting point that tends to backfill cracks. Drawbacks to adding a filler metal include a reduction in service temperature, a lowering of the tensile strength of the weld, and the possibility for galvanic corrosion to occur at the weld. To evaluate the degree of interaction between Be and Al-Si in an actual weld, sections from a mock beryllium weldment were exposed to 0.1 M Cl - solution. Results indicate that the galvanic couple between Be and the Al-Si weld material results in the cathodic protection of the weld and of the anodic dissolution of the bulk Be material. While the cathodic protection of Al is generally inefficient, the high anodic dissolution rate of the bulk Be during pitting corrosion combined with the insulating properties of the Be oxide afford some protection of the Al-Si weld material. Although dissolution of the Be precipitate in the weld material does occur, no corrosion of the Al-Si matrix was observed

  8. Electrocatalysts Prepared by Galvanic Replacement

    Directory of Open Access Journals (Sweden)

    Athanasios Papaderakis

    2017-03-01

    Full Text Available Galvanic replacement is the spontaneous replacement of surface layers of a metal, M, by a more noble metal, Mnoble, when the former is treated with a solution containing the latter in ionic form, according to the general replacement reaction: nM + mMnoblen+ → nMm+ + mMnoble. The reaction is driven by the difference in the equilibrium potential of the two metal/metal ion redox couples and, to avoid parasitic cathodic processes such as oxygen reduction and (in some cases hydrogen evolution too, both oxygen levels and the pH must be optimized. The resulting bimetallic material can in principle have a Mnoble-rich shell and M-rich core (denoted as Mnoble(M leading to a possible decrease in noble metal loading and the modification of its properties by the underlying metal M. This paper reviews a number of bimetallic or ternary electrocatalytic materials prepared by galvanic replacement for fuel cell, electrolysis and electrosynthesis reactions. These include oxygen reduction, methanol, formic acid and ethanol oxidation, hydrogen evolution and oxidation, oxygen evolution, borohydride oxidation, and halide reduction. Methods for depositing the precursor metal M on the support material (electrodeposition, electroless deposition, photodeposition as well as the various options for the support are also reviewed.

  9. Zinc toxicity among galvanization workers in the iron and steel industry.

    Science.gov (United States)

    El Safty, Amal; El Mahgoub, Khalid; Helal, Sawsan; Abdel Maksoud, Neveen

    2008-10-01

    Galvanization is the process of coating steel or cast iron pieces with zinc, allowing complete protection against corrosion. The ultimate goal of this work was to assess the effect of occupational exposure to zinc in the galvanization process on different metals in the human body and to detect the association between zinc exposure and its effect on the respiratory system. This study was conducted in 111 subjects in one of the major companies in the iron and steel industry. There were 61 subjects (workers) who were involved in the galvanization process. Fifty adult men were chosen as a matched reference group from other departments of the company. All workers were interviewed using a special questionnaire on occupational history and chest diseases. Ventilatory functions and chest X rays were assessed in all examined workers. Also, complete blood counts were performed, and serum zinc, iron, copper, calcium, and magnesium levels were tested. This study illustrated the relation between zinc exposure in the galvanization process and high zinc levels among exposed workers, which was associated with a high prevalence rate of metal fume fever (MFF) and low blood copper and calcium levels. There was no statistically significant difference between the exposed and control groups with regards to the magnesium level. No long-term effect of metals exposure was detected on ventilatory functions or chest X rays among the exposed workers.

  10. Laboratory studies of galvanic corrosion. III. Effect of velocity in NaCl and substitute ocean water

    International Nuclear Information System (INIS)

    Mansfeld, F.; Kenkel, J.V.

    1977-01-01

    The galvanic corrosion behavior of 4340 steel coupled to Type 304 stainless steel, Cu, Ti-6Al-4V, Al 2024, Al 6061, and zinc has been studied in 3.5 percent NaCl and ASTM substitute ocean water as a function of velocity using a rotating galvanic couple electrode holder. For steel coupled to Type 304 stainless steel, Cu or Ti, the galvanic current generally increases proportional to the square root of the rotation speed in both media. The increase is, however, smaller in the substitute ocean water. For couples involving Al alloys and Zn, the galvanic current has a more complicated dependence on velocity in substitute ocean water than in 3.5 percent NaCl

  11. Cold metal transfer spot plug welding of AA6061-T6-to-galvanized steel for automotive applications

    International Nuclear Information System (INIS)

    Cao, R.; Huang, Q.; Chen, J.H.; Wang, Pei-Chung

    2014-01-01

    Highlights: • Two Al-to-galvanized steel spot plug welding joints were studied by CMT method. • The optimum process variables for the two joints were gotten by orthogonal test. • Connection mechanism of the two joints were discussed. -- Abstract: In this study, cold metal transfer (CMT) spot plug joining of 1 mm thick Al AA6061-T6 to 1 mm thick galvanized steel (i.e., Q235) was studied. Welding variables were optimized for a plug weld in the center of a 25 mm overlap region with aluminum 4043 wire and 100% argon shielding gas. Microstructures and elemental distributions were characterized by scanning electron microscopy with energy dispersive X-ray spectrometer. Mechanical testing of CMT spot plug welded joints was conducted. It was found that it is feasible to join Al AA6061T6-to-galvanized steel by CMT spot plug welding method. The process variables for two joints with Al AA6061T6-to-galvanized mild steel and galvanized mild steel-to-Al AA6061T6 are optimized. The strength of CMT spot welded Al AA6061T6-to-galvanized mild steel is determined primarily by the strength and area of the brazed interface. While, the strength of the galvanized mild steel-to-Al AA6061T6 joint is mainly dependent upon the area of the weld metal

  12. Evolution of micro-arc oxidation behaviors of the hot-dipping aluminum coatings on Q235 steel substrate

    International Nuclear Information System (INIS)

    Lu Lihong; Shen Dejiu; Zhang Jingwu; Song Jian; Li Liang

    2011-01-01

    Micro-arc oxidation (MAO) is not applicable to prepare ceramic coatings on the surface of steel directly. In this work, hybrid method of MAO and hot-dipping aluminum (HDA) were employed to fabricate composite ceramic coatings on the surface of Q235 steel. The evolution of MAO coatings, such as growth rate, thickness of the total coatings, ingrown and outgrown coatings, cross section and surface morphologies and phase composition of the ceramic coatings were studied. The results indicate that both the current density and the processing time can affect the total thickness, the growth rate and the ratio of ingrown and outgrown thickness of the ceramic coatings. The total thickness, outgrown thickness and growth rate have maximum values with the processing time prolonged. The time when the maximum value appears decreases and the ingrown dominant turns to outgrown dominant little by little with the current density increasing. The composite coatings obtained by this hybrid method consists of three layers from inside to outside, i.e. Fe-Al alloy layer next to the substrate, aluminum layer between the Fe-Al layer and the ceramic coatings which is as the top exterior layer. Metallurgical bonding was observed between every of the two layers. There are many micro-pores and micro-cracks, which act as discharge channels and result of quick and non-uniform cooling of melted sections in the MAO coatings. The phase composition of the ceramic coatings is mainly composed of amorphous phase and crystal Al 2 O 3 oxides. The crystal Al 2 O 3 phase includes κ-Al 2 O 3 , θ-Al 2 O 3 and β-Al 2 O 3 . Compared with the others, the β-Al 2 O 3 content is the least. The MAO process can be divided into three periods, namely the common anodic oxidation stage, the stable MAO stage and the ceramic coatings destroyed stage. The exterior loose part of the ceramic coatings was destroyed badly in the last period which should be avoided during the MAO process.

  13. A Case Study Of Turkish Transmission System For VoltageDips

    DEFF Research Database (Denmark)

    Inan, E.; Alboyaci, B.; Bak, Claus Leth

    2009-01-01

    Power quality problems usually appear in the form of voltage sags, transients and harmonics. From these three broad categories of power quality problems, voltage dips account the most disturbances experienced by industrial customers. Voltage dips generally refer to instantaneous short-duration vo......Power quality problems usually appear in the form of voltage sags, transients and harmonics. From these three broad categories of power quality problems, voltage dips account the most disturbances experienced by industrial customers. Voltage dips generally refer to instantaneous short...... analysis of voltage dip performance of the whole transmission system, is used to compare with results constructed fault statics from SIMPOW DIPS analysis program real data. SIMPOW DIPS software enables to calculate dip frequency for all busses and lines....

  14. 77 FR 17430 - Galvanized Steel Wire From the People's Republic of China: Final Determination of Sales at Less...

    Science.gov (United States)

    2012-03-26

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-975] Galvanized Steel Wire From... Determination of sales at less than fair value (``LTFV'') in the antidumping investigation of galvanized steel... galvanized steel wire from the PRC is being, or is likely to be, sold in the United States at LTFV, as...

  15. 76 FR 72721 - Galvanized Steel Wire From China and Mexico; Scheduling of the Final Phase of Countervailing Duty...

    Science.gov (United States)

    2011-11-25

    ...)] Galvanized Steel Wire From China and Mexico; Scheduling of the Final Phase of Countervailing Duty and... galvanized steel wire, provided for in subheading 7217.20 of the Harmonized Tariff Schedule of the United... merchandise as galvanized steel wire which is a cold- drawn carbon quality steel product in coils, of solid...

  16. Deformation and damage mechanisms of zinc coatings on hot-dip galvanized steel sheets: Part II. Damage modes

    Science.gov (United States)

    Parisot, Rodolphe; Forest, Samuel; Pineau, André; Grillon, François; Demonet, Xavier; Mataigne, Jean-Michel

    2004-03-01

    Zinc-based coatings are widely used for protection against corrosion of steel-sheet products in the automotive industry. The objective of the present article is to investigate the damage modes at work in three different microstructures of a zinc coating on an interstitial-free steel substrate under tension, planestrain tension, and expansion loading. Plastic-deformation mechanisms are addressed in the companion article. Two main fracture mechanisms, namely, intergranular cracking and transgranular cleavage fracture, were identified in an untempered cold-rolled coating, a tempered cold-rolled coating, and a recrystallized coating. No fracture at the interface between the steel and zinc coating was observed that could lead to spalling, in the studied zinc alloy. A complex network of cleavage cracks and their interaction with deformation twinning is shown to develop in the material. An extensive quantitative analysis based on systematic image analysis provides the number and cumulative length of cleavage cracks at different strain levels for the three investigated microstructures and three loading conditions. Grain refinement by recrystallization is shown to lead to an improved cracking resistance of the coating. A model for crystallographic cleavage combining the stress component normal to the basal plane and the amount of plastic slip on the basal slip systems is proposed and identified from equibiaxial tension tests and electron backscattered diffraction (EBSD) analysis of the cracked grains. This analysis requires the computation of the nonlinear stress-strain response of each grain using a crystal-plasticity constitutive model. The model is then applied successfully to other loading conditions and is shown to account for the preferred orientations of damaged grains observed in the case of plane-strain tension.

  17. Active and reactive power control schemes for distributed generation systems under voltage dips

    NARCIS (Netherlands)

    Wang, F.; Duarte, J.L.; Hendrix, M.A.M.

    2009-01-01

    During voltage dips continuous power delivery from distributed generation systems to the grid is desirable for the purpose of grid support. In order to facilitate the control of distributed generation systems adapted to the expected change of grid requirements, generalized power control schemes

  18. Galvanic and stress corrosion of copper canisters in repository environment. A short review

    International Nuclear Information System (INIS)

    Hermansson, H.P.; Koenig, M.

    2001-02-01

    The Swedish Nuclear Power Inspectorate, SKI, has studied different aspects of canister and copper corrosion as part of the general improvement of the knowledge base within the area. General and local corrosion has earlier been treated by experiments as well as by thermodynamic calculations. For completeness also galvanic and stress corrosion should be treated. The present work is a short review, intended to indicate areas needing further focus. The work consists of two parts, the first of which contains a judgement of statements concerning risk of galvanic corrosion of copper in the repository. The second part concerns threshold values for the stress intensity factor of stress corrosion in copper. A suggestion is given on how such values possibly could be measured for copper at repository conditions. In early investigations by SKB, galvanic corrosion is not mentioned or at least not treated. In later works it is treated but often in a theoretical way without indications of any further treatment or investigation. Several pieces of work indicate that further investigations are required to ensure that different types of corrosion, like galvanic, cannot occur in the repository environment. There are for example effects of grain size, grain boundary conditions, impurities and other factors that could influence the appearance of galvanic corrosion that are not treated. Those factors have to be considered to be completely sure that galvanic corrosion and related effects does not occur for the actual canister in the specific environment of the repository. The circumstances are so specific, that a rather general discussion indicating that galvanic corrosion is not probable just is not enough. Experiments should also be performed for verification. It is concluded that the following specific areas, amongst others, could benefit from further consideration. Galvanic corrosion of unbreached copper by inhomogeneities in the environment and in the copper metal should be addressed

  19. Galvanic and stress corrosion of copper canisters in repository environment. A short review

    Energy Technology Data Exchange (ETDEWEB)

    Hermansson, H.P.; Koenig, M. [Studsvik Nuclear AB, Nykoeping (Sweden)

    2001-02-01

    The Swedish Nuclear Power Inspectorate, SKI, has studied different aspects of canister and copper corrosion as part of the general improvement of the knowledge base within the area. General and local corrosion has earlier been treated by experiments as well as by thermodynamic calculations. For completeness also galvanic and stress corrosion should be treated. The present work is a short review, intended to indicate areas needing further focus. The work consists of two parts, the first of which contains a judgement of statements concerning risk of galvanic corrosion of copper in the repository. The second part concerns threshold values for the stress intensity factor of stress corrosion in copper. A suggestion is given on how such values possibly could be measured for copper at repository conditions. In early investigations by SKB, galvanic corrosion is not mentioned or at least not treated. In later works it is treated but often in a theoretical way without indications of any further treatment or investigation. Several pieces of work indicate that further investigations are required to ensure that different types of corrosion, like galvanic, cannot occur in the repository environment. There are for example effects of grain size, grain boundary conditions, impurities and other factors that could influence the appearance of galvanic corrosion that are not treated. Those factors have to be considered to be completely sure that galvanic corrosion and related effects does not occur for the actual canister in the specific environment of the repository. The circumstances are so specific, that a rather general discussion indicating that galvanic corrosion is not probable just is not enough. Experiments should also be performed for verification. It is concluded that the following specific areas, amongst others, could benefit from further consideration. Galvanic corrosion of unbreached copper by inhomogeneities in the environment and in the copper metal should be addressed

  20. Galvanic high energy cells with molten electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Borger, W.; Kappus, W.; Kunze, D.; Laig-Hoerstebrock, H.; Panesar, H.; Sterr, G.

    1981-01-01

    To develop a galvanic cell with molten salt electrolyte for electric vehicle propulsion and load leveling as well as to fabricate ten prototype cells with a capacity of at least 150 Ah (5 hour rate) and an energy density of 80 Wh/kg was the objective of this project.

  1. A Galvanic Coupling Method for Assessing Hydration Rates

    Directory of Open Access Journals (Sweden)

    Clement Ogugua Asogwa

    2016-07-01

    Full Text Available Recent advances in biomedical sensors, data acquisition techniques, microelectronics and wireless communication systems opened up the use of wearable technology for ehealth monitoring. We introduce a galvanic coupled intrabody communication for monitoring human body hydration. Studies in hydration provide the information necessary for understanding the desired fluid levels for optimal performance of the body’s physiological and metabolic processes during exercise and activities of daily living. Current measurement techniques are mostly suitable for laboratory purposes due to their complexity and technical requirements. Less technical methods such as urine color observation and skin turgor testing are subjective and cannot be integrated into a wearable device. Bioelectrical impedance methods are popular but mostly used for estimating total body water with limited accuracy and sensitive to 800 mL–1000 mL change in body fluid levels. We introduce a non-intrusive and simple method of tracking hydration rates that can detect up to 1.30 dB reduction in attenuation when as little as 100 mL of water is consumed. Our results show that galvanic coupled intrabody signal propagation can provide qualitative hydration and dehydration rates in line with changes in an individual’s urine specific gravity and body mass. The real-time changes in galvanic coupled intrabody signal attenuation can be integrated into wearable electronic devices to evaluate body fluid levels on a particular area of interest and can aid diagnosis and treatment of fluid disorders such as lymphoedema.

  2. A study on vestibular-evoked myogenic potentials via galvanic vestibular stimulation in normal people

    Directory of Open Access Journals (Sweden)

    Ying Cheng

    2018-03-01

    Discussions: Galvanic vestibular stimulation could elicit biphasic EMG responses from SCM via the vestibular nerve but not from the otolith organs. Galvanic stimulation together with air conducted sound (ACS or bone conducted vibration (BCV can elicit VEMPs and may enable the differentiation of retrolabyrinthine lesions from labyrinthine lesions in vestibular system.

  3. Corrosion of welded steel piping in domestic hot water: A case history. Corrosion de una instalacion de tubos soldados de acero galvanizado para agua caliente

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, E J; Soria, L; Gallardo, J M

    1993-01-01

    Many leaks had occurred after seven years of service in the hot sanitary water system of building. The results of the failure analysis have led to the conclusion that the reduced life of the piping system was primarily promoted by the use of a dissimilar metal (galvanized steel-copper) installation and by an excessive service temperature. Through precuations were taking to electrically insulate both types of tubing by employing dielectric fittings and water flow followed the ''rule of flow'' (zinc[yields] copper), an indirect galvanic attach on galvanized steel took place. Localized corrosion was originated by microcells formed by plating out of soluble copper. Corrosive attack was most severe at weld seams. The microstructure of the weld zone was very different from that of the surrounding pipe. In addition, some pipes presented signs of incomplete fusion (welding without filling metal) and others had protruding weld seams which produced crevice attack and erosion-corrosion, respectively. Author (10 refs.)

  4. Attenuation of pressure dips underneath piles of spherocylinders.

    Science.gov (United States)

    Zhao, Haiyang; An, Xizhong; Gou, Dazhao; Zhao, Bo; Yang, Runyu

    2018-05-30

    The discrete element method (DEM) was used to simulate the piling of rod-like (elongated sphero-cylindrical) particles, mainly focusing on the effect of particle shape on the structural and force properties of the piles. In this work, rod-like particles of different aspect ratios were discharged on a flat surface to form wedge-shaped piles. The surface properties of the piles were characterized in terms of angle of repose and stress at the bottom of the piles. The results showed that the rise of the angle of repose became slower with the increase of particle aspect ratio. The pressure dip underneath the piles reached the maximum when the particle aspect ratio was around 1.6, beyond which the pressure dip phenomenon became attenuated. Both the pressure dip and the shear stress dip were quantitatively examined. The structure and forces inside the piles were further analyzed to understand the change in pressure dip, indicating that "bridging" or "arching" structures within the piles were the cause of the pressure dip.

  5. Self-oscillating Galvanic Isolated Bidirectional Very High Frequency DC-DC Converter

    DEFF Research Database (Denmark)

    Pedersen, Jeppe Arnsdorf; Madsen, Mickey Pierre; Knott, Arnold

    2015-01-01

    This paper describes a galvanic isolated bidirectional Very High Frequency (VHF = 30 MHz - 300MHz) ClassE converter. The reason for increasing the switching frequency is to minimize the passive components in the converter. To make the converter topology bidirectional the rectifier has to be synch......This paper describes a galvanic isolated bidirectional Very High Frequency (VHF = 30 MHz - 300MHz) ClassE converter. The reason for increasing the switching frequency is to minimize the passive components in the converter. To make the converter topology bidirectional the rectifier has...

  6. Effect of gamma irradiation combined with hot water treatment on the texture, pulp color and sensory quality of ''Nahng Glahng Wahn'' mangoes

    International Nuclear Information System (INIS)

    Lacroix, M.; Jobin, M.; Beliveau, M.; Gagnon, M.

    1992-01-01

    Mangoes (Mangifera indica L.) from Thailand of the 'Nahng Glahng Wahn' variety were irradiated with a 60 Co source at a dose of 0.63 kGy and a dose rate of 9.23 kGy/hr, with or without a hot water treatment prior to irradiation. The irradiation treatment had little effect on the texture and preserved the yellow color in the pulp. Test of sensory evaluation revealed that irradiated mango pulp was preferred for overall appearance, taste, texture and palatability. The appearance of whole irradiated mangoes was also preferred over that of the control mangoes. However, no significant differences were observed between irradiated and hot water dipped irradiated mangoes for all characteristics studied in mangoes pulp. The results showed that these treatments (hot water dip plus irradiation or irradiation alone) are useful and non-destructive methods to preserve consumer acceptability

  7. Effects of Mg on corrosion resistance of Al galvanically coupled to Fe

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, Youngmin; Kim, Heesan [Hongik Univ., Sejong (Korea, Republic of)

    2013-01-15

    Effects of magnesium and pH on corrosion of aluminum galvanically coupled to iron have studied by using potentio- dynamic and static tests for polarization curves, Mott-Schottky test for analysis of semiconductor property, and GD-AES and XPS for film analysis. Pitting potential was sensitive to magnesium as an alloying element but not to pH, while passive current was sensitive to pH but not to magnesium. It was explained with, instead of point defect model (PDM), surface charge model describing that the ingression of chloride depends on the state of surface charge and passive film at film/solution interface is affected by pH. In addition, galvanic current of aluminum electrically coupled to iron was not affected by magnesium in pH 8.4, 0.2M citrate solution but was increased by magnesium at the solution of pH 9.1. The galvanic current at pH 9.1 increased with time at the initial stage and after the exposure of about 200 minute, decreased and stabilized. The behavior of the galvanic current was related with the concentration of magnesium at the surface. It agreed with the depletion of magnesium at the oxide surface by using glow discharge atomic emission spectroscopy (GD-AES). In addition, pitting potential of pure aluminum was reduced in neutral pH solution where chloride ion maybe are competitively adsorbed on pure aluminum. It was confirmed by the exponential decrease of pitting potential with log of [Cl{sup -}] around 0.025 M of [Cl{sup -}] and linear decrease of the pitting potential. From the above results, unlike magnesium, alloying elements with higher electron negativity, lowering isoelectric point (ISE), are recommended to be added to improve pitting corrosion resistance of aluminum and its alloys in neutral solutions as well as their galvanic corrosion resistance in weakly basic solutions.

  8. Effects of Mg on corrosion resistance of Al galvanically coupled to Fe

    International Nuclear Information System (INIS)

    Hyun, Youngmin; Kim, Heesan

    2013-01-01

    Effects of magnesium and pH on corrosion of aluminum galvanically coupled to iron have studied by using potentio- dynamic and static tests for polarization curves, Mott-Schottky test for analysis of semiconductor property, and GD-AES and XPS for film analysis. Pitting potential was sensitive to magnesium as an alloying element but not to pH, while passive current was sensitive to pH but not to magnesium. It was explained with, instead of point defect model (PDM), surface charge model describing that the ingression of chloride depends on the state of surface charge and passive film at film/solution interface is affected by pH. In addition, galvanic current of aluminum electrically coupled to iron was not affected by magnesium in pH 8.4, 0.2M citrate solution but was increased by magnesium at the solution of pH 9.1. The galvanic current at pH 9.1 increased with time at the initial stage and after the exposure of about 200 minute, decreased and stabilized. The behavior of the galvanic current was related with the concentration of magnesium at the surface. It agreed with the depletion of magnesium at the oxide surface by using glow discharge atomic emission spectroscopy (GD-AES). In addition, pitting potential of pure aluminum was reduced in neutral pH solution where chloride ion maybe are competitively adsorbed on pure aluminum. It was confirmed by the exponential decrease of pitting potential with log of [Cl - ] around 0.025 M of [Cl - ] and linear decrease of the pitting potential. From the above results, unlike magnesium, alloying elements with higher electron negativity, lowering isoelectric point (ISE), are recommended to be added to improve pitting corrosion resistance of aluminum and its alloys in neutral solutions as well as their galvanic corrosion resistance in weakly basic solutions

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Yunze Xu

    2016-09-01

    Full Text Available In this paper, a new kind of carbon steel (CS and stainless steel (SS galvanic sensor system was developed for the study of rebar corrosion in different pore solution conditions. Through the special design of the CS and SS electronic coupons, the electronic resistance (ER method and zero resistance ammeter (ZRA technique were used simultaneously for the measurement of both the galvanic current and the corrosion depth. The corrosion processes in different solution conditions were also studied by linear polarization resistance (LPR and the measurements of polarization curves. The test result shows that the galvanic current noise can provide detailed information of the corrosion processes. When localized corrosion occurs, the corrosion rate measured by the ER method is lower than the real corrosion rate. However, the value measured by the LPR method is higher than the real corrosion rate. The galvanic current and the corrosion current measured by the LPR method shows linear correlation in chloride-containing saturated Ca(OH2 solution. The relationship between the corrosion current differences measured by the CS electronic coupons and the galvanic current between the CS and SS electronic coupons can also be used to evaluate the localized corrosion in reinforced concrete.

  11. Cattle dipping practices in the Philippines and the degradation of coumaphos in a simulated cattle dip

    International Nuclear Information System (INIS)

    Calumpang, S.M.F.; Medina, M.J.B.; Tejada, A.W.

    1997-01-01

    A survey of cattle dip facilities and current practices employed was done. Coumaphos and ethion were the commonly used acaricides in the four respondent stock farms. The behavior of coumaphos in a simulated model cattle dip was monitored using radiotracer techniques. Degradation was rapid, resulting in the formation of potasan metabolite and bound residues in the sediment. A rapid field method for the detection of organophosphate pesticides was used in monitoring the degradation of coumaphos in a cattle dip. The sensitivity of the method is comparable to the conventional HPLC method employed. This rapid field method can easily be used by cattle ranch owners to monitor coumaphos content of the vat facility so that recharging could be made in order to prevent the onset of resistance development in cattle tick. (author)

  12. Connecting elements for wind power plants with an enhanced vibration resistance; Verbindungselemente fuer Windenergieanlagen mit erhoehter Schwingfestigkeit

    Energy Technology Data Exchange (ETDEWEB)

    Hasselmann, Uwe; Braun, Tobias [Peiner Umformtechnik GmbH, Peine (Germany)

    2010-07-01

    In wind power plants, large quantities of screws with large dimensions are used. This concerns to steel construction screws according to the regulations DIN EN 14399-4 or DASt 021. These screws are hot-galvanized. The wind power plants are exposed to large stochastic oscillation loads. Therefore, there exist fatigue proof procedures which follow a regulation from the construction sector (DIN EN 1993-1-9) and still are continued to specify in a certification guideline of the Germanic Lloyd. Within the range of mechanical engineering of wind power plants, a strength verification of the screwed joints follows the VDI regulation 2230. The vibration resistance of the screw is an input for the proof of vibration resistance. During the production of screws with an enhanced vibration resistance in the hot-galvanized condition one may dispense with the reducing coefficients for hot-galvanizing due to the technical measures. The use of connecting elements with enhanced vibration resistance enables the dimensioning of ring flange joints with less or smaller screws. This economically can be of advantage, since this positively affects the dimensions of the flange. In the borderline case with enhanced swinging loads the computational proof is enabled yet.

  13. Galvanic Vestibular Stimulation in Hemi-Spatial Neglect

    Directory of Open Access Journals (Sweden)

    David eWilkinson

    2014-01-01

    Full Text Available Hemi-spatial neglect is an attentional disorder in which the sufferer fails to acknowledge or respond to stimuli appearing in contralesional space. In recent years, it has become clear that a measurable reduction in contralesional neglect can occur during galvanic vestibular stimulation, a technique by which transmastoid, small amplitude current induces lateral, attentional shifts via asymmetric modulation of the left and right vestibular nerves. However, it remains unclear whether this reduction persists after stimulation is stopped. To estimate longevity of effect, we therefore conducted a double-blind, randomized, dose-response trial involving a group of stroke patients suffering from left-sided neglect (n=52, mean age=66 years. To determine whether repeated sessions of galvanic vestibular stimulation more effectively induce lasting relief than a single session, participants received 1, 5, or 10 sessions, each lasting 25mins, of sub-sensory, left-anodal right-cathodal noisy direct current (mean amplitude=1mA. Ninety five percent confidence intervals indicated that all three treatment arms showed a statistically significant improvement between the pre-stimulation baseline and the final day of stimulation on the primary outcome measure, the conventional tests of the Behavioural Inattention Test. More remarkably, this change (mean change=28%, SD=18 was still evident 1month later. Secondary analyses indicated an allied increase of 20% in median Barthel Index score, a measure of functional capacity, in the absence of any adverse events or instances of participant non-compliance. Together these data suggest that galvanic vestibular stimulation, a simple, cheap technique suitable for home-based administration, may produce lasting reductions in neglect that are clinically important. Further protocol optimization is now needed ahead of a larger effectiveness study.

  14. Galvanic Cells: Anodes, Cathodes, Signs and Charges

    Science.gov (United States)

    Goodwin, Alan

    2011-01-01

    Electrochemistry is a difficult subject for students at school and beyond and even for their teachers. This article explores the difficult "truth" that, when a current flows from a galvanic cell, positive ions within the cell electrolyte move towards the electrode labelled positive. This seems to contravene the basic rule that like charges repel…

  15. Application of Boundary Element Method in Galvanic Corrosion Analysis for Metallic Materials used in Nuclear Power Plant

    International Nuclear Information System (INIS)

    Zaifol Samsu; Muhamad Daud; Siti Radiah Mohd Kamarudin

    2011-01-01

    Boundary element method (BEM) is a numerical technique that used for modeling infinite domain as is the case for galvanic corrosion analysis. This paper presents the application of boundary element method for galvanic corrosion analysis between two different metallic materials. Aluminium (Al), and zinc (Zn) alloys were used separately coupled with the Carbon Steel (CS) in natural seawater. The measured conductivity of sea water is 30,800 μS/ cm at ambient temperature. Computer software system based on boundary element likes BEASY and ABAQUS can be used to accurately model and simulate the galvanic corrosion. However, the BEM based BEASY program will be used reasonably for predicting the galvanic current density distribution of coupled Al-CS and Zn-CS in this study. (author)

  16. Microbiologically influenced corrosion of galvanized steel by Desulfovibrio sp. and Desulfosporosinus sp. in the presence of Ag–Cu ions

    Energy Technology Data Exchange (ETDEWEB)

    Ilhan-Sungur, Esra, E-mail: esungur@istanbul.edu.tr [Istanbul University, Faculty of Science, Department of Biology, 34134 Vezneciler, Istanbul (Turkey); Unsal-Istek, Tuba [Istanbul University, Faculty of Science, Department of Biology, 34134 Vezneciler, Istanbul (Turkey); Cansever, Nurhan [Yıldız Technical University, Faculty of Chemistry-Metallurgy, Metallurgical and Materials Engineering Department, 34210 Esenler, Istanbul (Turkey)

    2015-07-15

    The effects of Ag–Cu ions on the microbiologically induced corrosion of galvanized steel in the presence of Desulfovibrio sp. and Desulfosporosinus sp. were investigated. The corrosion behavior of galvanized steel was analyzed by potentiodynamic polarization and electrochemical impedance spectroscopy. The biofilm, corrosion products and Ag–Cu ions on the surfaces were investigated by using scanning electron microscopy, energy dispersive X-ray spectrometry and elemental mapping. The biofilm layer formed by the Desulfovibrio sp. was stable covering the all surface of galvanized steel coupons, while that by Desulfosporosinus sp. was intermittent, highly porous and heterogeneous. It was found that both of the sulfate reducing bacteria species accelerated corrosion of the galvanized steel. However, it was detected that Desulfosporosinus sp. was more corrosive for galvanized steel than Desulfovibrio sp. Scanning electron microscopy images showed that Desulfovibrio sp. and Desulfosporosinus sp. in biofilm clustered into patches on the galvanized steel surface when the culture contained toxic Ag–Cu ions. The ions affected the growth of the sulfate reducing bacteria strains in different ways and hence the corrosion behaviors. It was observed that the Ag–Cu ions affected negatively growth of Desulfosporosinus sp. especially after 24 h of exposure leading to a decrease in the corrosion rate of galvanized steel. However, Desulfovibrio sp. showed more corrosive effect in the presence of the ions according to the ions-free culture. Energy dispersive X-ray spectrometry analysis showed that corrosion products on the surfaces were mainly composed of Zn, S, Na, O and P. - Highlights: • Galvanized steel was corroded by Desulfosporosinus sp. and Desulfovibrio sp. • Desulfosporosinus sp. is more corrosive than Desulfovibrio sp. • The Ag–Cu ions affected corrosion behavior of Desulfosporosinus sp. and Desulfovibrio sp. on galvanized steel.

  17. Microbiologically influenced corrosion of galvanized steel by Desulfovibrio sp. and Desulfosporosinus sp. in the presence of Ag–Cu ions

    International Nuclear Information System (INIS)

    Ilhan-Sungur, Esra; Unsal-Istek, Tuba; Cansever, Nurhan

    2015-01-01

    The effects of Ag–Cu ions on the microbiologically induced corrosion of galvanized steel in the presence of Desulfovibrio sp. and Desulfosporosinus sp. were investigated. The corrosion behavior of galvanized steel was analyzed by potentiodynamic polarization and electrochemical impedance spectroscopy. The biofilm, corrosion products and Ag–Cu ions on the surfaces were investigated by using scanning electron microscopy, energy dispersive X-ray spectrometry and elemental mapping. The biofilm layer formed by the Desulfovibrio sp. was stable covering the all surface of galvanized steel coupons, while that by Desulfosporosinus sp. was intermittent, highly porous and heterogeneous. It was found that both of the sulfate reducing bacteria species accelerated corrosion of the galvanized steel. However, it was detected that Desulfosporosinus sp. was more corrosive for galvanized steel than Desulfovibrio sp. Scanning electron microscopy images showed that Desulfovibrio sp. and Desulfosporosinus sp. in biofilm clustered into patches on the galvanized steel surface when the culture contained toxic Ag–Cu ions. The ions affected the growth of the sulfate reducing bacteria strains in different ways and hence the corrosion behaviors. It was observed that the Ag–Cu ions affected negatively growth of Desulfosporosinus sp. especially after 24 h of exposure leading to a decrease in the corrosion rate of galvanized steel. However, Desulfovibrio sp. showed more corrosive effect in the presence of the ions according to the ions-free culture. Energy dispersive X-ray spectrometry analysis showed that corrosion products on the surfaces were mainly composed of Zn, S, Na, O and P. - Highlights: • Galvanized steel was corroded by Desulfosporosinus sp. and Desulfovibrio sp. • Desulfosporosinus sp. is more corrosive than Desulfovibrio sp. • The Ag–Cu ions affected corrosion behavior of Desulfosporosinus sp. and Desulfovibrio sp. on galvanized steel

  18. Galvanic vestibular stimulation speeds visual memory recall.

    Science.gov (United States)

    Wilkinson, David; Nicholls, Sophie; Pattenden, Charlotte; Kilduff, Patrick; Milberg, William

    2008-08-01

    The experiments of Alessandro Volta were amongst the first to indicate that visuo-spatial function can be altered by stimulating the vestibular nerves with galvanic current. Until recently, the beneficial effects of the procedure were masked by the high levels of electrical current applied, which induced nystagmus-related gaze deviation and spatial disorientation. However, several neuropsychological studies have shown that much weaker, imperceptible currents that do not elicit unpleasant side-effects can help overcome visual loss after stroke. Here, we show that visual processing in neurologically healthy individuals can also benefit from galvanic vestibular stimulation. Participants first learnt the names of eight unfamiliar faces and then after a short delay, answered questions from memory about how pairs of these faces differed. Mean correct reaction times were significantly shorter when sub-sensory, noise-enhanced anodal stimulation was administered to the left mastoid, compared to when no stimulation was administered at all. This advantage occurred with no loss in response accuracy, and raises the possibility that the procedure may constitute a more general form of cognitive enhancement.

  19. Dioxin generation in hot dip galvanising installations in Spain during 2002; Evaluacion de la generacion de dioxinas y furanos en el sector de galvanizacion en caliente durante el ano 2002

    Energy Technology Data Exchange (ETDEWEB)

    Fabrellas Rodriguez, B.; Ruiz Lorenzo, M. L.; Martinez Calvo, M. A.; Sanz Chincon, P.; Larrazabal Moya, D.

    2003-07-01

    Hot dip galvanising sector has been evaluated in the frame of Spanish Dioxin Inventory to estimate their importance as a source of dioxins through their air emissions and wastes generated. The survey has been designed taken into account different pre-treatment surface preparation processes, mainly in degreasing steps. Air emissions, ashes and filter dusts have been sampled and toxic dioxins have been analysed. The results have been correlated with the characteristics of each installation. Dioxins releases to the air are very low when air control devices are used but they are concentrated in filter dusts that appear highly contaminated. Both air and dusts samples present the same dioxin homologue profile and different from ashes, which implies two different ways of formation where organic content, temperature and residence time should place important rules. The organic content could be originated, in some cases, by the degrease step absence, the low efficiency in grease removing and/or by the presence of organic inhibitors and additives used in picking steps. (Author)

  20. Effects of galvanic distortions on magnetotelluric data: Interpretation ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    But in the case of field data the problem is ... The distorted data set is corrected using the MT response for DRS model and further ... ments, the apparent resistivity and phase at differ- ... from the telluric field, which is of galvanic or inductive ...

  1. Photo-electrochemical Investigation of Radiation-Enhanced Galvanic Coupling and Hydrogen Permeation in TPBAR-related Materials

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-10-02

    Research conducted in FY17 used photo-electrochemical methods to investigate the potential for radiationenhanced galvanic coupling in tritium-producing burnable absorber rod (TPBAR) materials. Specifically, a laboratory electrochemical cell was coupled with UV light in order to perform electrochemical opencircuit voltage and galvanic current measurements, techniques that have been used successfully in previous studies to replicate galvanic processes in reactor settings. UV irradiation can mimic reactor-like behavior because, similar to both directly and indirectly ionizing radiation, UV photons with energy greater than the band gap of the material will generate free charge carriers (electrons and holes) and can substantially alter the passivating effect of metal oxides.

  2. Photo-electrochemical Investigation of Radiation-Enhanced Galvanic Coupling and Hydrogen Permeation in TPBAR-related Materials

    International Nuclear Information System (INIS)

    Larsen, G.

    2017-01-01

    Research conducted in FY17 used photo-electrochemical methods to investigate the potential for radiationenhanced galvanic coupling in tritium-producing burnable absorber rod (TPBAR) materials. Specifically, a laboratory electrochemical cell was coupled with UV light in order to perform electrochemical opencircuit voltage and galvanic current measurements, techniques that have been used successfully in previous studies to replicate galvanic processes in reactor settings. UV irradiation can mimic reactor-like behavior because, similar to both directly and indirectly ionizing radiation, UV photons with energy greater than the band gap of the material will generate free charge carriers (electrons and holes) and can substantially alter the passivating effect of metal oxides.

  3. Corrosion behaviour and galvanic coupling of titanium and welded titanium in LiBr solutions

    International Nuclear Information System (INIS)

    Blasco-Tamarit, E.; Igual-Munoz, A.; Garcia Anton, J.; Garcia-Garcia, D.

    2007-01-01

    Corrosion resistance and galvanic coupling of Grade 2 commercially pure titanium in its welded and non-welded condition were systematically analyzed in LiBr solutions. Galvanic corrosion was evaluated through two different methods: anodic polarization (according to the Mixed Potential Theory) and electrochemical noise (using a zero-resistance ammeter). Samples have been etched to study the microstructure. The action of lithium chromate as corrosion inhibitor has been evaluated. Titanium and welded titanium showed extremely low corrosion current densities and elevated pitting potential values (higher than 1 V). The results of both methods, anodic polarization and electrochemical noise, showed that the welded titanium was always the anodic element of the pair titanium-welded titanium, so that its corrosion resistance decreases due to the galvanic effect

  4. Galvanic interactions of HE15 /MDN138 & HE15 /MDN250 alloys in natural seawater

    Science.gov (United States)

    Parthiban, G. T.; Subramanian, G.; Muthuraman, K.; Ramakrishna Rao, P.

    2017-06-01

    HE15 is a heat treatable high strength alloy with excellent machinability find wide applications in aerospace and defence industries. In view of their excellent mechanical properties, workability, machinability, heat treatment characteristics and good resistance to general and stress corrosion cracking, MDN138 & MDN250 have been widely used in petrochemical, nuclear and aerospace industries. The galvanic corrosion behaviour of the metal combinations HE15 /MDN138 and HE15 /MDN250, with 1:1 area ratio, has been studied in natural seawater using the open well facility of CECRI's Offshore Platform at Tuticorin for a year. The open circuit potentials of MDN138, MDN250 and HE15 of the individual metal, the galvanic potential and galvanic current of the couples HE15 /MDN138 and HE15 /MDN250 were periodically monitored throughout the study period. The calcareous deposits on MDN138 and MDN250 in galvanic contact with HE15 were analyzed using XRD. The electrochemical behaviors of MDN138, MDN250 and HE15 in seawater have been studied using an electrochemical work station. The surface characteristics of MDN138 and MDN250 in galvanic contact with HE15 have been examined with scanning electron microscope. The results of the study reveal that HE15 offered required amount of protection to MDN138 & MDN250.

  5. Very High Frequency Galvanic Isolated Offline Power Supply

    DEFF Research Database (Denmark)

    Pedersen, Jeppe Arnsdorf

    During the last decades many researchers have turned their attention to raising the operation frequency of power converters to the very high frequency (VHF) range going from 30 MHz to 300 MHz. Increasing the operating frequency of a power converter leads to smaller energy storing components...... inverters with a single combined rectifier. The converter designed to deliver 9 W to a 60 V LED load and is achieving an efficiency of 89.4% and a power density of 2.14 W3 . The development of this converter proof that offline VHF converter can be implemented with high efficiencies even for low power applications...... are described together with the possibility of using capacitors as the power galvanic isolation, both methods of creating galvanic isolation are implemented in converters. Regarding EMC a series of converters with different filter implementations are examined. The results from the conducted mea-surement from 150...

  6. Complex approach mechanical properties and formability assessment of selected deep-drawing steels

    Directory of Open Access Journals (Sweden)

    J. Štaba

    2009-07-01

    Full Text Available The paper analyses the properties of deep-drawing sheets of three grades (Re = 320 to 475 MPa, surface-treated with hot-dip galvanizing, made of microalloyed steels. Deformation properties are assessed using tensile tests, technological Erichsen or cupping tests. These characteristics, as well as the behaviour of the surface layer, are also investigated under dynamic conditions (modified Erichsen test using a drop tester, or using flat bending fatigue tests. Using microscopic analysis the deformation properties of the surface layer are evaluated. The results show the compactness of the surface layer, high deformation characteristics, as well as fatigue properties of the investigated deep-drawing materials, suitable for application in the automotive industry.

  7. Assessment of Automotive Coatings Used on Different Metallic Substrates

    Directory of Open Access Journals (Sweden)

    W. Bensalah

    2014-01-01

    Full Text Available Four epoxy primers commonly used in the automotive industry were applied by gravity pneumatic spray gun over metallic substrates, specifically, steel, electrogalvanized steel, hot-dip galvanized steel, and aluminum. A two-component polyurethane resin was used as topcoat. To evaluate the performance of the different coating systems, the treated panels were submitted to mechanical testing using Persoz hardness, impact resistance, cupping, lattice method, and bending. Tribological properties of different coating systems were conducted using pin on disc machine. Immersion tests were carried out in 5% NaCl and immersion tests in 3% NaOH solutions. Results showed which of the coating systems is more suitable for each substrate in terms of mechanical, tribological, and anticorrosive performance.

  8. Fabrication of tubed functionally graded material by slurry dipping process. Thickness control of dip-coated layer

    International Nuclear Information System (INIS)

    Watanabe, Ryuzo

    1997-03-01

    In order to obtain long life fuel cladding tubes for the fast breeder reactor, the concept of functionally graded material was applied for the material combination of Molybdenum/stainless steel/Titanium, in which Titanium and Molybdenum were placed at the inner and outer sides, respectively. Slurry dipping method was employed because of its capability of shape forming and microstructural control. We have hitherto reported the design criteria for the graded layers, preparation of the slurry, and microstructural control of the dip-coated layers. In the present report, the thickness control of the dip-coated layer is described in detail. The thickness of the dip-coated layer depends primarily on the viscosity of the slurry. Nevertheless, for the stable dispersion of the powder in the slurry, which dominates the microstructural homogeneity, an optimum viscosity value is present for the individual slurries. With stable slurries of Ti, Mo, stainless steel powders and their mixtures, the thicknesses of dip-coated layers were controlled in dependence of their viscosities and yield values. For Ti and stainless steel powders and their mixture a PAANa was used as a dispersing agent. A NaHMP was found to be effective for the dispersion of Mo powder and Mo/stainless steel powder mixture. For all slurries tested in the present investigation PVA addition was helpful for the viscosity control. Dip-coating maps have been drawn for the stabilization of the slurries and for the formation of films with a sufficient strength for further manipulation for the slurries with low viscosity (∼10 mPa s). The final film thickness for the low-viscosity slurry with the optimum condition was about 200 μm. The slurries with high viscosities of several hundreds mPa s had a good stability and the yield value was easy to be controlled. The film thickness was able to be adjusted in the size range between several tens and several hundreds μm. The final thickness of the graded layer was determined

  9. Evolution of micro-arc oxidation behaviors of the hot-dipping aluminum coatings on Q235 steel substrate

    Energy Technology Data Exchange (ETDEWEB)

    Lu Lihong, E-mail: llh_qc@163.com [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China) and Research Department, The Chinese People' s Armed Police Academy, Langfang 065000 (China); Shen Dejiu; Zhang Jingwu [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Song Jian; Li Liang [Tsinghua University, State Key Laboratory of Automotive Safety and Energy, Beijing 100084 (China)

    2011-02-15

    Micro-arc oxidation (MAO) is not applicable to prepare ceramic coatings on the surface of steel directly. In this work, hybrid method of MAO and hot-dipping aluminum (HDA) were employed to fabricate composite ceramic coatings on the surface of Q235 steel. The evolution of MAO coatings, such as growth rate, thickness of the total coatings, ingrown and outgrown coatings, cross section and surface morphologies and phase composition of the ceramic coatings were studied. The results indicate that both the current density and the processing time can affect the total thickness, the growth rate and the ratio of ingrown and outgrown thickness of the ceramic coatings. The total thickness, outgrown thickness and growth rate have maximum values with the processing time prolonged. The time when the maximum value appears decreases and the ingrown dominant turns to outgrown dominant little by little with the current density increasing. The composite coatings obtained by this hybrid method consists of three layers from inside to outside, i.e. Fe-Al alloy layer next to the substrate, aluminum layer between the Fe-Al layer and the ceramic coatings which is as the top exterior layer. Metallurgical bonding was observed between every of the two layers. There are many micro-pores and micro-cracks, which act as discharge channels and result of quick and non-uniform cooling of melted sections in the MAO coatings. The phase composition of the ceramic coatings is mainly composed of amorphous phase and crystal Al{sub 2}O{sub 3} oxides. The crystal Al{sub 2}O{sub 3} phase includes {kappa}-Al{sub 2}O{sub 3}, {theta}-Al{sub 2}O{sub 3} and {beta}-Al{sub 2}O{sub 3}. Compared with the others, the {beta}-Al{sub 2}O{sub 3} content is the least. The MAO process can be divided into three periods, namely the common anodic oxidation stage, the stable MAO stage and the ceramic coatings destroyed stage. The exterior loose part of the ceramic coatings was destroyed badly in the last period which should be

  10. Enhancement of opto-galvanic signals in the hollow cathode dark space: application to single colour 3-photon ionization of uranium

    International Nuclear Information System (INIS)

    Pradhan, S.; Manohar, K.G.; Marathe, A.; Rawat, V.S.; Sridhar, G.; Singh, S.; Jagatap, B.N.; Gantayet, L.M.

    1999-01-01

    Opto-galvanic effect in a hollow cathode lamp offers a very convenient method of spectroscopy of many elements of interest including refractory elements like uranium. The dependence of opto-galvanic signals on various discharge parameters like buffer gas pressure, buffer gas type, discharge current, diameter of the hollow cavity of the cathode etc. have been studied. Various mechanisms for the generation of opto-galvanic signals based on electron impact ionization and super elastic collisions have been proposed. It appears that both these processes do contribute to the opto-galvanic signals simultaneously, under specific discharge conditions

  11. Electrochemical characteristics of a carbon fibre composite and the associated galvanic effects with aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Z., E-mail: zuojia.liu@gmail.com; Curioni, M.; Jamshidi, P.; Walker, A.; Prengnell, P.; Thompson, G.E.; Skeldon, P.

    2014-09-30

    Highlights: • Exposed carbon fibres on two defined regions (“front” and “side”) are a focus of the investigation in NaCl electrolyte. • The exposed carbon fibres on the side and front regions are responsible for a high cathodic current density. • The NaCl + CuSO{sub 4} electrolyte was used to investigate the cathodic polarization behaviour of the exposed carbon fibres. • Galvanic coupling behaviour between the composite and aluminium alloys (AA7075-T6 and AA1050) was measured in NaCl electrolyte. • The higher galvanic current density measured on AA1050 alloy introduced a higher dissolution rate than the AA7075-T6 alloy. - Abstract: The electrochemical behaviour of a carbon fibre reinforced epoxy matrix composite in 3.5% NaCl and 3.5% NaCl + 0.5 M CuSO{sub 4} electrolytes was examined by potentiodynamic polarisation, potentiostatic polarisation and scanning electron microscopy. Exposed carbon fibres on two defined regions (“front” and “side”) are a focus of the investigation. The large size of the exposed carbon fibres on the side region is responsible for a higher cathodic current density than the front region in the NaCl electrolyte. The deposition of copper on the front surface of composite confirmed that the significantly higher cathodic current resulted from the exposure of the fibres to the NaCl electrolyte. Galvanic coupling between the composite and individual aluminium alloys (AA7075-T6 and AA1050) was used to measure galvanic potentials and galvanic current densities. The highly alloyed AA7075-T6 alloy and its high population density of cathodic sites compared to the AA1050 acted to reduce the galvanic effect when coupled to the composite front or side regions.

  12. E-Cigs, Menthol & Dip

    Science.gov (United States)

    ... Close Search × MENU BACK CLOSE SMOKEFREE.GOV HOME E-Cigs, Menthol & Dip There are many types of tobacco products. Learn how e-cigarettes, menthol cigarettes, smokeless tobacco, and other products ...

  13. Destructive role of hot ions in the formation of electrostatic density humps and dips in dusty plasmas

    International Nuclear Information System (INIS)

    Mahmood, S.; Saleem, H.

    2003-01-01

    It is shown that the ion thermal energy is destructive for the ion acoustic solitons in the presence of dust, and it decreases the value of Mach number for the formation of solitary structures. The regions of ion density humps and dips are produced simultaneously, corresponding to positive and negative values of the electrostatic potential. The nonlinear electron density also behaves in a similar fashion as that of ions. However, the dust density increases in the regions where the ion and electron densities are depleted and vice versa

  14. Intracavity OptoGalvanic Spectroscopy not suitable for ambient level radiocarbon detection.

    Science.gov (United States)

    Paul, Dipayan; Meijer, Harro A J

    2015-09-01

    IntraCavity OptoGalvanic Spectroscopy as a radiocarbon detection technique was first reported by the Murnick group at Rutgers University, Newark, NJ, in 2008. This technique for radiocarbon detection was presented with tremendous potentials for applications in various fields of research. Significantly cheaper, this technique was portrayed as a possible complementary technique to the more expensive and complex accelerator mass spectrometry. Several groups around the world started developing this technique for various radiocarbon related applications. The IntraCavity OptoGalvanic Spectroscopy setup at the University of Groningen was constructed in 2012 in close collaboration with the Murnick group for exploring possible applications in the fields of radiocarbon dating and atmospheric monitoring. In this paper we describe a systematic evaluation of the IntraCavity OptoGalvanic Spectroscopy setup at Groningen for radiocarbon detection. Since the IntraCavity OptoGalvanic Spectroscopy setup was strictly planned for dating and atmospheric monitoring purposes, all the initial experiments were performed with CO2 samples containing contemporary levels and highly depleted levels of radiocarbon. Because of recurring failures in differentiating the two CO2 samples, with the radiocarbon concentration 3 orders of magnitude apart, CO2 samples containing elevated levels of radiocarbon were prepared in-house and experimented with. All results obtained thus far at Groningen are in sharp contrast to the results published by the Murnick group and rather support the results put forward by the Salehpour group at Uppsala University. From our extensive test work, we must conclude that the method is unsuited for ambient level radiocarbon measurements, and even highly enriched CO2 samples yield insignificant signal.

  15. Fiber Finishes for Improving Galvanic Resistance of Imide-Based Composites

    National Research Council Canada - National Science Library

    Allred, R. E

    1998-01-01

    The objective of this program is the development and demonstration of galvanic corrosion resistant carbon/ BMI composites through the use of reactive finishes to form coatings that isolate the carbon...

  16. Microstructure and failure behavior of dissimilar resistance spot welds between low carbon galvanized and austenitic stainless steels

    International Nuclear Information System (INIS)

    Marashi, P.; Pouranvari, M.; Amirabdollahian, S.; Abedi, A.; Goodarzi, M.

    2008-01-01

    Resistance spot welding was used to join austenitic stainless steel and galvanized low carbon steel. The relationship between failure mode and weld fusion zone characteristics (size and microstructure) was studied. It was found that spot weld strength in the pullout failure mode is controlled by the strength and fusion zone size of the galvanized steel side. The hardness of the fusion zone which is governed by the dilution between two base metals, and fusion zone size of galvanized carbon steel side are dominant factors in determining the failure mode

  17. Gravity interpretation of dipping faults using the variance analysis method

    International Nuclear Information System (INIS)

    Essa, Khalid S

    2013-01-01

    A new algorithm is developed to estimate simultaneously the depth and the dip angle of a buried fault from the normalized gravity gradient data. This algorithm utilizes numerical first horizontal derivatives computed from the observed gravity anomaly, using filters of successive window lengths to estimate the depth and the dip angle of a buried dipping fault structure. For a fixed window length, the depth is estimated using a least-squares sense for each dip angle. The method is based on computing the variance of the depths determined from all horizontal gradient anomaly profiles using the least-squares method for each dip angle. The minimum variance is used as a criterion for determining the correct dip angle and depth of the buried structure. When the correct dip angle is used, the variance of the depths is always less than the variances computed using wrong dip angles. The technique can be applied not only to the true residuals, but also to the measured Bouguer gravity data. The method is applied to synthetic data with and without random errors and two field examples from Egypt and Scotland. In all cases examined, the estimated depths and other model parameters are found to be in good agreement with the actual values. (paper)

  18. Corrosion in ICPP fuel storage basins

    International Nuclear Information System (INIS)

    Dirk, W.J.

    1993-09-01

    The Idaho Chemical Processing Plant currently stores irradiated nuclear fuel in fuel storage basins. Historically, fuel has been stored for over 30 years. During the 1970's, an algae problem occurred which required higher levels of chemical treatment of the basin water to maintain visibility for fuel storage operations. This treatment led to higher levels of chlorides than seen previously which cause increased corrosion of aluminum and carbon steel, but has had little effect on the stainless steel in the basin. Corrosion measurements of select aluminum fuel storage cans, aluminum fuel storage buckets, and operational support equipment have been completed. Aluminum has exhibited good general corrosion rates, but has shown accelerated preferential attack in the form of pitting. Hot dipped zinc coated carbon steel, which has been in the basin for approximately 40 years, has shown a general corrosion rate of 4 mpy, and there is evidence of large shallow pits on the surface. A welded Type 304 stainless steel corrosion coupon has shown no attack after 13 years exposure. Galvanic couples between carbon steel welded to Type 304 stainless steel occur in fuel storage yokes exposed to the basin water. These welded couples have shown galvanic attack as well as hot weld cracking and intergranular cracking. The intergranular stress corrosion cracking is attributed to crevices formed during fabrication which allowed chlorides to concentrate

  19. Analysis of Postural Control Adaptation During Galvanic and Vibratory Stimulation

    National Research Council Canada - National Science Library

    Fransson, P

    2001-01-01

    The objective for this study was to investigate whether the postural control adaptation during galvanic stimulation of the vestibular nerve were similar to that found during vibration stimulation to the calf muscles...

  20. Galvanic Cells and the Determination of Equilibrium Constants

    Science.gov (United States)

    Brosmer, Jonathan L.; Peters, Dennis G.

    2012-01-01

    Readily assembled mini-galvanic cells can be employed to compare their observed voltages with those predicted from the Nernst equation and to determine solubility products for silver halides and overall formation constants for metal-ammonia complexes. Results obtained by students in both an honors-level first-year course in general chemistry and…

  1. 40 CFR 68.85 - Hot work permit.

    Science.gov (United States)

    2010-07-01

    ... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CHEMICAL ACCIDENT PREVENTION PROVISIONS Program 3 Prevention Program § 68.85 Hot work permit. (a) The owner or operator shall issue a hot work permit for hot work operations conducted on or near a covered process. (b...

  2. Comparison of piracetam measured with HPLC-DAD, HPLC-ESI-MS, DIP-APCI-MS, and a newly developed and optimized DIP-ESI-MS.

    Science.gov (United States)

    Lenzen, Claudia; Winterfeld, Gottfried A; Schmitz, Oliver J

    2016-06-01

    The direct inlet probe-electrospray ionization (DIP-ESI) presented here was based on the direct inlet probe-atmospheric pressure chemical ionization (DIP-APCI) developed by our group. It was coupled to an ion trap mass spectrometer (MS) for the detection of more polar compounds such as degradation products from pharmaceuticals. First, the position of the ESI tip, the gas and solvent flow rates, as well as the gas temperature were optimized with the help of the statistic program Minitab® 17 and a caffeine standard. The ability to perform quantitative analyses was also tested by using different concentrations of caffeine and camphor. Calibration curves with a quadratic calibration regression of R (2) = 0.9997 and 0.9998 for caffeine and camphor, respectively, were obtained. The limit of detection of 2.5 and 1.7 ng per injection for caffeine and camphor were determined, respectively. Furthermore, a solution of piracetam was used to compare established analytical methods for this drug and its impurities such as HPLC-diode array detector (DAD) and HPLC-ESI-MS with the DIP-APCI and the developed DIP-ESI. With HPLC-DAD and 10 μg piracetam on column, no impurity could be detected. With HPLC-ESI-MS, two impurities (A and B) were identified with only 4.6 μg piracetam on column, while with DIP-ESI, an amount of 1.6 μg piracetam was sufficient. In the case of the DIP-ESI measurements, all detected impurities could be identified by MS/MS studies. Graphical Abstract Scheme of the DIP-ESI principle.

  3. Galvanizing industry: evaluation of exposure levels using biomonitors

    International Nuclear Information System (INIS)

    Menezes, Maria Angela de B.C.; Sabino, Claudia de V.S.; Amaral, Angela Maria; Mattos, Silvania V. de M.; S. Filho, Serafim; Maia, Elene Cristina P.

    1999-01-01

    In Brazil, statistical surveys concerning occupational diseases refer to accidents and damages. The surveys do not refer to the occupational diseases developed through long exposures to hazardous work conditions, involving physical risk and toxic chemical substances. The Program of Medical Control of Occupational Health determines the Maximum Biological Levels Allowed and the Values of Normality References. But concerning metal and toxic inorganic, values of only few elements are established. In Belo Horizonte and surroundings areas, which is an important industrial centre in the country, there are different industries distributed over various areas. There are about 80 galvanizing industries which are responsible for the majority of the metal contamination hospitalities. A preliminary sampling was performed in order to conduct a survey of the exposures to elements related to occupational diseases in galvanizing industry. The preliminary results for toxic and non-toxic elements obtained using hair and fingernails as biomonitors are shown. The K 0 parametric neutron activation analysis method was applied and the elements determined were: Ag, Al, Au, Cl, Co, Cr, Cu, Fe, I, Mn, Na, Ti, V, Ta, and Zn. (author)

  4. Hydrothermal–galvanic couple synthesis of directionally oriented BaTiO3 thin films on TiN-coated substrates

    International Nuclear Information System (INIS)

    Yang, Chia-Jung; Tsai, Di-You; Chan, Pei-Hsuan; Wu, Chu-Tsun; Lu, Fu-Hsing

    2013-01-01

    BaTiO 3 films were synthesized on TiN-coated Si substrate below 100 °C by a hydrothermal–galvanic couple technique in barium contained alkaline solutions. X-ray diffraction and electron backscatter diffraction results show that the BaTiO 3 thin films were directionally oriented grown on the TiN/Si substrates, i.e., (111) BaTiO 3 over (111) TiN. The surface morphologies revealed that BaTiO 3 nucleated and grew over the TiN surface with a single layer. From kinetic analyses, the growth rates of BaTiO 3 films prepared by the hydrothermal–galvanic couple technique were faster than a hydrothermal method. The galvanic effects were confirmed by investigating the induced currents and energies. The galvanic currents were generated and controlled by both the dissolution of TiN and the formation of BaTiO 3 . The output electric energies increased rapidly with the reaction time and leveled off at the full coverage of BaTiO 3 . - Highlights: • Cubic BaTiO 3 films are synthesized by a hydrothermal–galvanic couple method (HT–GC). • Growth rates of BaTiO 3 films made by HT–GC are faster than a hydrothermal method. • BaTiO 3 films are directionally oriented grown on the TiN/Si substrates. • Galvanic currents are controlled by dissolution of TiN and formation of BaTiO 3

  5. The influence of Reynolds number on the galvanic corrosion of the copper/AISI 304 pair in aqueous LiBr solutions

    International Nuclear Information System (INIS)

    Montanes, M.T.; Sanchez-Tovar, R.; Garcia-Anton, J.; Perez-Herranz, V.

    2009-01-01

    The influence of Reynolds number on the galvanic corrosion of the copper/AISI 304 stainless steel pair in a concentrated lithium bromide solution was investigated according to the mixed potential theory. A hydraulic circuit was designed to study dynamic corrosion processes in situ. A potential relation between corrosion current density (i corr ) and Reynolds number (Re) was found for copper, showing a mixed control of a chemical step and mass transport through the corrosion products film with the predominance of the former. No dependence of i corr on Re could be established for AISI 304, showing a chemical step control. Moreover, under stagnant conditions, partial passivation may occur in AISI 304; however, under flowing conditions passivation is not possible. Copper is the anodic element of the pair under all flowing conditions analysed. The galvanic phenomenon is more important as Re increases, but the results show compatibility of both materials at all Re values analysed. Similarly, a potential relation between galvanic current density (i G ) and Re was found, showing a mixed control of a chemical step and mass transport with the predominance of the latter. Copper corrosion resistance decreases more rapidly as Re increases due to the AISI 304 galvanic effect: there is a synergy between the galvanic effect and the hydrodynamic conditions. Under stagnant conditions, the galvanic behaviour of the materials is close to the compatibility limit and an inversion of the anodic element of the galvanic pair takes place.

  6. Improvement of the galvanized coating quality of high strength dual phase steels by pre-electroplating nickel layer

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, N. [Institute of Marine Materials Science and Engineering, Shanghai Maritime University, Shanghai 200135 (China); Zhang, K. [Institute of Concrete Pumps Machinery R and D, Sany Heavy Industry Co., Ltd. 410100 (China); Li, J. [Baoshan Iron and Steel Co., Ltd, Shanghai 201900 (China); Hu, W.B. [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2011-03-15

    Galvanized dual phase steel sheets are used extensively in the industrial applications because of their excellent mechanical properties and superior corrosion resistance, but the segregation of alloying elements and the formation of oxides on the steel surface often have a deleterious effect on coating adhesion during the galvanizing process. In order to improve the coating quality, a nickel layer was pre-electroplated on the steel substrate before galvanizing and it's found that there is an improvement in the coating quality. The coating microstructures were investigated by scanning electron microscopy together with energy dispersive X-ray spectroscope, glow discharge optical emission spectroscope and X-ray diffractions. The experimental results show that the compact Ni{sub 3}Zn{sub 22} intermetallic layer formed at the zinc/nickel interface during the galvanizing process, prohibiting the nucleation and the growth of the {zeta}-Zn phase layer and resulting in the improvement of the zinc coating adhesion. (Copyright copyright 2011 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Social support and nocturnal blood pressure dipping: a systematic review.

    Science.gov (United States)

    Fortmann, Addie L; Gallo, Linda C

    2013-03-01

    Attenuated nocturnal blood pressure (BP) dipping is a better predictor of cardiovascular disease (CVD) morbidity and mortality than resting BP measurements. Studies have reported associations between social support, variously defined, and BP dipping. A systematic review of the literature was conducted to investigate associations of functional and structural social support with nocturnal BP dipping assessed over a minimum of 24 hours. A total of 297 articles were identified. Of these, 11 met criteria for inclusion; all studies were cross-sectional in design and included adult participants only (mean age = 19 to 72 years). Evidence was most consistent for an association between functional support and BP dipping, such that 5 of 7 studies reported statistically (or marginally) significant positive associations with BP dipping. Statistically significant functional support-BP dipping associations were moderate (standardized effect size (d) = 0.41) to large (d = 2.01) in magnitude. Studies examining structural support were fewer and relatively less consistent; however, preliminary evidence was observed for associations of marital status and social contact frequency with BP dipping. Statistically significant structural support findings were medium (d = 0.53) to large (d = 1.13) in magnitude. Overall, findings suggest a link between higher levels of functional support and greater nocturnal BP dipping; preliminary evidence was also observed for the protective effects of marriage and social contact frequency. Nonetheless, the relatively small number of studies conducted to date and the heterogeneity of findings across meaningful subgroups suggest that additional research is needed to substantiate these conclusions.

  8. Digitally Controlled Offline Converter with Galvanic Isolation Based on an 8-bit Microcontroller

    DEFF Research Database (Denmark)

    Jakobsen, Lars Tønnes; Andersen, Michael Andreas E.

    2007-01-01

    This paper presents an offline AC/DC converter with digital control and galvanic isolation that can be implemented using cheap commercially available components. An ATMEL ATTiny26 8-bit microcontroller is used to control the converter. The microcontroller is placed on the secondary side of the co......This paper presents an offline AC/DC converter with digital control and galvanic isolation that can be implemented using cheap commercially available components. An ATMEL ATTiny26 8-bit microcontroller is used to control the converter. The microcontroller is placed on the secondary side...

  9. Eigenvector of gravity gradient tensor for estimating fault dips considering fault type

    Science.gov (United States)

    Kusumoto, Shigekazu

    2017-12-01

    The dips of boundaries in faults and caldera walls play an important role in understanding their formation mechanisms. The fault dip is a particularly important parameter in numerical simulations for hazard map creation as the fault dip affects estimations of the area of disaster occurrence. In this study, I introduce a technique for estimating the fault dip using the eigenvector of the observed or calculated gravity gradient tensor on a profile and investigating its properties through numerical simulations. From numerical simulations, it was found that the maximum eigenvector of the tensor points to the high-density causative body, and the dip of the maximum eigenvector closely follows the dip of the normal fault. It was also found that the minimum eigenvector of the tensor points to the low-density causative body and that the dip of the minimum eigenvector closely follows the dip of the reverse fault. It was shown that the eigenvector of the gravity gradient tensor for estimating fault dips is determined by fault type. As an application of this technique, I estimated the dip of the Kurehayama Fault located in Toyama, Japan, and obtained a result that corresponded to conventional fault dip estimations by geology and geomorphology. Because the gravity gradient tensor is required for this analysis, I present a technique that estimates the gravity gradient tensor from the gravity anomaly on a profile.

  10. Hot electron formation in thermal barrier region of tandem mirror GAMMA 10

    International Nuclear Information System (INIS)

    Katanuma, I.; Kiwamoto, Y.; Sawada, K.; Miyoshi, S.

    1987-01-01

    We have studied the hot electron build-up by the second harmonic electron cyclotron resonance heating in the thermal barrier region of tandem mirror GAMMA 10 by using a Fokker-Planck code with self-consistent potential profile taken into account. We have found two phases in the evolution of hot electron population and the potential profile. In the first phase where the RF diffusion is dominant quick increase of the hot electron density and that of the mean energy are observed. No further increase in the mean energy is observed thereafter. The potential is the deepest during the first phase. The second phase starts in the mean-free-time of the pitch angle scattering of hot electrons on cold electrons and ions. In this phase the hot electron population increases in the rate of the pitch angle scattering. The potential dip shallows due to the accumulation of pitch angle scattered passing ions. This observation indicates the necessity of the ion pumping for maintaining the negative potential at the thermal barrier. (author)

  11. Novel Galvanic Corrosion Inhibitors: Synthesis, Characterization, Fabrication and Testing

    Science.gov (United States)

    2007-09-30

    Polyimide Insulated Electrical Wire", SAMPE pp.16, Jan/Feb 1984. 11. Brown, S. R.; Deluccia, J.J., " Galvanic Corrosion Fatigue Testing of 7075-T6...Modified Microporous Aluminosilicate" Development of Adsorbents for Air and Water Treatment Conference, 226th American Chemical Society (ACS) National

  12. T-DNA transfer and T-DNA integration efficiencies upon Arabidopsis thaliana root explant cocultivation and floral dip transformation.

    Science.gov (United States)

    Ghedira, Rim; De Buck, Sylvie; Van Ex, Frédéric; Angenon, Geert; Depicker, Ann

    2013-12-01

    T-DNA transfer and integration frequencies during Agrobacterium-mediated root explant cocultivation and floral dip transformations of Arabidopsis thaliana were analyzed with and without selection for transformation-competent cells. Based on the presence or absence of CRE recombinase activity without or with the CRE T-DNA being integrated, transient expression versus stable transformation was differentiated. During root explant cocultivation, continuous light enhanced the number of plant cells competent for interaction with Agrobacterium and thus the number of transient gene expression events. However, in transformation competent plant cells, continuous light did not further enhance cotransfer or cointegration frequencies. Upon selection for root transformants expressing a first T-DNA, 43-69 % of these transformants showed cotransfer of another non-selected T-DNA in two different light regimes. However, integration of the non-selected cotransferred T-DNA occurred only in 19-46 % of these transformants, indicating that T-DNA integration in regenerating root cells limits the transformation frequencies. After floral dip transformation, transient T-DNA expression without integration could not be detected, while stable T-DNA transformation occurred in 0.5-1.3 % of the T1 seedlings. Upon selection for floral dip transformants with a first T-DNA, 8-34 % of the transformants showed cotransfer of the other non-selected T-DNA and in 93-100 % of them, the T-DNA was also integrated. Therefore, a productive interaction between the agrobacteria and the female gametophyte, rather than the T-DNA integration process, restricts the floral dip transformation frequencies.

  13. Pseudarthrosis due to galvanic corrosion presenting as subarachnoid hemorrhage

    Directory of Open Access Journals (Sweden)

    Rosemary Noel Beavers

    2017-01-01

    Full Text Available Two unlike metals near one another can break down as they move toward electrochemical equilibrium resulting in galvanic corrosion. We describe a case of electrochemical corrosion resulting in pseudarthrosis, followed by instrumentation failure leading to subarachnoid hemorrhage. A 53-year-old female with a history of cervical instability and two separate prior cervical fusion surgery with sublaminar cables presented with new onset severe neck pain. Restricted range of motion in her neck and bilateral Hoffman's was noted. X-ray of her cervical spine was negative. A noncontrast CT scan of her head and neck showed subarachnoid hemorrhage in the prepontine and cervicomedullary cisterns. Neurosurgical intervention involved removal of prior stainless steel and titanium cables, repair of cerebrospinal fluid leak, and nonsegmental C1–C3 instrumented fusion. She tolerated the surgery well and followed up without complication. Galvanic corrosion of the Brook's fusion secondary to current flow between dissimilar metal alloys resulted in catastrophic instrumentation failure and subarachnoid hemorrhage.

  14. Anticorrosion protection of strength bolts

    Directory of Open Access Journals (Sweden)

    Jiří Votava

    2012-01-01

    Full Text Available Corrosion damage may, from the technical point of view, cause changes in mechanical and physical characteristics in particular, at the same time it may also cause changes in surface geometry. These aspects are likely to manifest themselves in all steel parts. The presented study looks at corrosion protection in bolts and bolt connections protected by metal coating based on zinc.Four different types of passivation, easily accessible on the Czech market, have been selected for this experiment. They are as follows: first, galvanic plating using white zinc; second, galvanic plating using yellow zinc; third, hot dip galvanizing; fourth, specific type of plating using the technology Dacromet 500 LC. In order to compare the given parameters there have been selected a unified M bolt size of 8 × 30 mm. The experimental part of this study can be further divided into two phases. The initial phase puts stress on the exact specification of the protection layer, namely, the analysis and establishment of the elemental compositon contained in the given coating, its microhardness, weight and thickness. The second phase of the experiment analyses the results of tests according to the norm ČSN ISO 9227 (Salt Fog Test and ČSN ISO 6988 (Sulphur Dioxide Test. With the tests we have concentrated on the initial stages of corrosion degradation and its overall process.

  15. Corrosion by galvanic coupling on the steam generator auxiliary feedwater pumps at the level of the steam-tight boxes

    International Nuclear Information System (INIS)

    Dordonat, M.; Huet, M.

    1994-01-01

    Corrosion by galvanic coupling in steam generator auxiliary pump is coming from electroplated chromium cracks for the rotor steel, and from chemical KANIGEN nickel cracks for the steam-tight boxes black steel. To avoid galvanic coupling between Cr coating and the rotor steel, first an electrolytic Ni coating is done followed by an electrolytic Cr coating. To avoid galvanic coupling between black steel and graphite rings, black steel is replaced by 316L steel. (A.B.). 1 ref., 7 figs

  16. Cycle oxidation behavior and anti-oxidation mechanism of hot-dipped aluminum coating on TiBw/Ti6Al4V composites with network microstructure.

    Science.gov (United States)

    Li, X T; Huang, L J; Wei, S L; An, Q; Cui, X P; Geng, L

    2018-04-10

    Controlled and compacted TiAl 3 coating was successfully fabricated on the network structured TiBw/Ti6Al4V composites by hot-dipping aluminum and subsequent interdiffusion treatment. The network structure of the composites was inherited to the TiAl 3 coating, which effectively reduces the thermal stress and avoids the cracks appeared in the coating. Moreover, TiB reinforcements could pin the TiAl 3 coating which can effectively improve the bonding strength between the coating and composite substrate. The cycle oxidation behavior of the network structured coating on 873 K, 973 K and 1073 K for 100 h were investigated. The results showed the coating can remarkably improve the high temperature oxidation resistance of the TiBw/Ti6Al4V composites. The network structure was also inherited to the Al 2 O 3 oxide scale, which effectively decreases the tendency of cracking even spalling about the oxide scale. Certainly, no crack was observed in the coating after long-term oxidation due to the division effect of network structured coating and pinning effect of TiB reinforcements. Interfacial reaction between the coating and the composite substrate occurred and a bilayer structure of TiAl/TiAl 2 formed next to the substrate after oxidation at 973 K and 1073 K. The anti-oxidation mechanism of the network structured coating was also discussed.

  17. Width and dip of the southern San Andreas Fault at Salt Creek from modeling of geophysical data

    Science.gov (United States)

    Langenheim, Victoria; Athens, Noah D.; Scheirer, Daniel S.; Fuis, Gary S.; Rymer, Michael J.; Goldman, Mark R.; Reynolds, Robert E.

    2014-01-01

    We investigate the geometry and width of the southernmost stretch of the San Andreas Fault zone using new gravity and magnetic data along line 7 of the Salton Seismic Imaging Project. In the Salt Creek area of Durmid Hill, the San Andreas Fault coincides with a complex magnetic signature, with high-amplitude, short-wavelength magnetic anomalies superposed on a broader magnetic anomaly that is at least 5 km wide centered 2–3 km northeast of the fault. Marine magnetic data show that high-frequency magnetic anomalies extend more than 1 km west of the mapped trace of the San Andreas Fault. Modeling of magnetic data is consistent with a moderate to steep (> 50 degrees) northeast dip of the San Andreas Fault, but also suggests that the sedimentary sequence is folded west of the fault, causing the short wavelength of the anomalies west of the fault. Gravity anomalies are consistent with the previously modeled seismic velocity structure across the San Andreas Fault. Modeling of gravity data indicates a steep dip for the San Andreas Fault, but does not resolve unequivocally the direction of dip. Gravity data define a deeper basin, bounded by the Powerline and Hot Springs Faults, than imaged by the seismic experiment. This basin extends southeast of Line 7 for nearly 20 km, with linear margins parallel to the San Andreas Fault. These data suggest that the San Andreas Fault zone is wider than indicated by its mapped surface trace.

  18. Eco-technological process of glass-ceramic production from galvanic sludge and aluminium slag

    Directory of Open Access Journals (Sweden)

    Stanisavljević M.

    2010-01-01

    Full Text Available Methods of purification of waste water which are most commonly used in the Republic of Serbia belong to the type of conventional systems for purification such as chemical oxidation and reduction, neutralization, sedimentation, coagulation, and flocculation. Consequently, these methods generate waste sludge which, unless adequately stabilized, represents hazardous matter. The aluminium slag generated by melting or diecasting aluminium and its alloys is also hazardous matter. In this sense, this paper establishes ecological risk of galvanic waste sludge and aluminium slag and then describes the process of stabilization of these waste materials by means of transformation into a glass-ceramic structure through sintering. The obtained product was analyzed with Fourier Transform Infrared Spectroscopy (FT-IR and X-ray diffraction (XRD. The object of the paper is the eco-technological process of producing glass-ceramics from galvanic sludge and aluminium slag. The aim of the paper is to incorporate toxic metals from galvanic sludge and aluminium slag into the glass-ceramic product, in the form of solid solutions.

  19. 76 FR 19382 - Galvanized Steel Wire From China and Mexico

    Science.gov (United States)

    2011-04-07

    ... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 701-TA-479 and 731-TA-1183-1184 (Preliminary)] Galvanized Steel Wire From China and Mexico AGENCY: United States International Trade Commission. ACTION... the United States is materially retarded, by reason of [[Page 19383

  20. Photo-galvanic effect in Bi2Se3 thin films with ionic liquid gating

    Science.gov (United States)

    Pan, Yu; Richardella, Anthony; Lee, Joon Sue; Flanagan, Thomas; Samarth, Nitin

    2013-03-01

    A key challenge in three dimensional (3D) topological insulators (TIs) is to reveal the helical spin-polarized surface states via electrical transport measurements. A recent study [Nature Nanotech. 7, 96 (2012)] showed that circularly polarized light can be used to generate and control photocurrents in the 3D TI Bi2Se3, even at photon energies that are well above the bulk band gap. Symmetry considerations suggest that this ``photo-galvanic effect'' arises purely from photo-currents induced in the surface Dirac states. To gain insights into this phenomenon, we have carried out systematic measurements of the photo-galvanic effect in electrically gated MBE-grown Bi2Se3 thin films of varying thickness. By using an ionic liquid as an optically transparent gate, we map out the behavior of the photo-galvanic effect as a function of Fermi energy over a temperature range 5 K <= T <= 300 K. Supported by ONR and NSF.

  1. An Easy-to-Assemble Three-Part Galvanic Cell

    Science.gov (United States)

    Eggen, Per-Odd; Skaugrud, Brit

    2015-01-01

    The galvanic cell presented in this article is made of only three parts, is easy to assemble, and can light a red light emitting diode (LED). The three cell components consist of a piece of paper with copper sulfate, a piece of paper with sodium sulfate, and a piece of magnesium ribbon. Within less than 1 h, students have time to discuss the…

  2. Valorización de un residuo proveniente de la industria de galvanizado en caliente mediante la síntesis hidrometalúrgica de sales de zinc

    Directory of Open Access Journals (Sweden)

    Julio Andrés Casal-Ramos

    2011-10-01

    Full Text Available The possibility of adding value to a residual dust from hot-dip galvanizing process was explored, through the synthesis of potentially marketable organic zinc salts. The valorization process started by dissolving the residue in HCl, citric acid was then added and zinc salts were finally precipitated by the addition of NaOH. In another experiment, absolute ethanol was added as a modifying agent. In both cases, the products were fine white powders which were characterized by pycnometry, atomic spectroscopy, scanning electron microscopy, x–ray diffraction and infrared spectroscopy. In the synthesized products, the following phases were identified: Zn(C2H3O22.2H2O, Na3C6H5O7.2H2O and NaCl

  3. Corrosion Resistance of Zinc Coatings With Aluminium Additive

    Directory of Open Access Journals (Sweden)

    Votava Jiří

    2014-08-01

    Full Text Available This paper is focused on evaluation of anticorrosion protection of inorganic metal coatings such as hot-dipped zinc and zinc-galvanized coatings. The thickness and weight of coatings were tested. Further, the evaluation of ductile characteristics in compliance with the norm ČSN EN ISO 20482 was processed. Based on the scratch tests, there was evaluated undercorrosion in the area of artificially made cut. Corrosion resistance was evaluated in compliance with the norm ČSN EN ISO 9227 (salt-spray test. Based on the results of the anticorrosion test, there can be stated corrosion resistance of each individual protective coating. Tests were processed under laboratory conditions and may vary from tests processed under conditions of normal atmosphere.

  4. 76 FR 21914 - Galvanized Steel Wire From China and Mexico

    Science.gov (United States)

    2011-04-19

    ... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 701-TA-479 and 731-TA-1183-1184 (Preliminary)] Galvanized Steel Wire From China and Mexico AGENCY: United States International Trade Commission. ACTION: Revised schedule for the subject antidumping and countervailing duty investigations. DATES: Effective Date...

  5. Influence of the Manufacturing Process on Defects in the Galvanized Coating of High Carbon Steel Wires

    Directory of Open Access Journals (Sweden)

    Marcello Gelfi

    2017-03-01

    Full Text Available This study is a detailed failure analysis of galvanized high carbon steel wires, which developed coating cracks during the torsion test performed as a quality control at the end of the manufacturing process. Careful visual inspections showed that the cracks are already present in the coating before the torsion test. In order to explain the origin of these cracks, systematic metallographic investigations were performed by means of optical and scanning electron microscope on both the wires and the rods that have been cold drawn to produce the wire. The chemical composition of the galvanized coatings was evaluated by means of energy dispersive spectroscopy. Micro bidimensional X-ray diffraction experiments were also performed to measure the residual stresses in the galvanized coating. The results showed that the failure is related to two main factors: the relatively high content of silicon in the steel and the unsuitable cooling rate of the rods at the exit from the galvanizing bath. The mechanism proposed to explain the origin of the defects was supported by Finite Elements Methods simulations and verified with in-plant tests. The proper countermeasures were then applied and the problem successfully solved.

  6. Influence of the Manufacturing Process on Defects in the Galvanized Coating of High Carbon Steel Wires.

    Science.gov (United States)

    Gelfi, Marcello; Solazzi, Luigi; Poli, Sandro

    2017-03-06

    This study is a detailed failure analysis of galvanized high carbon steel wires, which developed coating cracks during the torsion test performed as a quality control at the end of the manufacturing process. Careful visual inspections showed that the cracks are already present in the coating before the torsion test. In order to explain the origin of these cracks, systematic metallographic investigations were performed by means of optical and scanning electron microscope on both the wires and the rods that have been cold drawn to produce the wire. The chemical composition of the galvanized coatings was evaluated by means of energy dispersive spectroscopy. Micro bidimensional X-ray diffraction experiments were also performed to measure the residual stresses in the galvanized coating. The results showed that the failure is related to two main factors: the relatively high content of silicon in the steel and the unsuitable cooling rate of the rods at the exit from the galvanizing bath. The mechanism proposed to explain the origin of the defects was supported by Finite Elements Methods simulations and verified with in-plant tests. The proper countermeasures were then applied and the problem successfully solved.

  7. Effects of heat input on mechanical properties of metal inert gas welded 1.6 mm thick galvanized steel sheet

    International Nuclear Information System (INIS)

    Rafiqul, M I; Ishak, M; Rahman, M M

    2012-01-01

    It is usually a lot easier and less expensive to galvanize steel before it is welded into useful products. Galvanizing afterwards is almost impossible. In this research work, Galvanized Steel was welded by using the ER 308L stainless steel filler material. This work was done to find out an alternative way of welding and investigate the effects of heat input on the mechanical properties of butt welded joints of Galvanized Steel. A 13.7 kW maximum capacity MIG welding machine was used to join 1.6 mm thick sheet of galvanized steel with V groove and no gap between mm. Heat inputs was gradually increased from 21.06 to 25.07 joules/mm in this study. The result shows almost macro defects free welding and with increasing heat input the ultimate tensile strength and welding efficiency decrease. The Vickers hardness also decreases at HAZ with increasing heat input and for each individual specimen; hardness was lowest in heat affected zone (HAZ), intermediate in base metal and maximum in welded zone. The fracture for all specimens was in the heat affected zone while testing in the universal testing machine.

  8. Effects of heat input on mechanical properties of metal inert gas welded 1.6 mm thick galvanized steel sheet

    Science.gov (United States)

    Rafiqul, M. I.; Ishak, M.; Rahman, M. M.

    2012-09-01

    It is usually a lot easier and less expensive to galvanize steel before it is welded into useful products. Galvanizing afterwards is almost impossible. In this research work, Galvanized Steel was welded by using the ER 308L stainless steel filler material. This work was done to find out an alternative way of welding and investigate the effects of heat input on the mechanical properties of butt welded joints of Galvanized Steel. A 13.7 kW maximum capacity MIG welding machine was used to join 1.6 mm thick sheet of galvanized steel with V groove and no gap between mm. Heat inputs was gradually increased from 21.06 to 25.07 joules/mm in this study. The result shows almost macro defects free welding and with increasing heat input the ultimate tensile strength and welding efficiency decrease. The Vickers hardness also decreases at HAZ with increasing heat input and for each individual specimen; hardness was lowest in heat affected zone (HAZ), intermediate in base metal and maximum in welded zone. The fracture for all specimens was in the heat affected zone while testing in the universal testing machine.

  9. Database of Interacting Proteins (DIP)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The DIP database catalogs experimentally determined interactions between proteins. It combines information from a variety of sources to create a single, consistent...

  10. Diamondlike carbon coating as a galvanic corrosion barrier between dental implant abutments and nickel-chromium superstructures.

    Science.gov (United States)

    Ozkomur, Ahmet; Erbil, Mehmet; Akova, Tolga

    2013-01-01

    The objectives of this study were to evaluate the galvanic corrosion behavior between titanium and nickel-chromium (Ni-Cr) alloy, to investigate the effect of diamondlike carbon (DLC) coating over titanium on galvanic corrosion behavior between titanium and Ni-Cr alloy, and to evaluate the effect of DLC coating over titanium abutments on the fit and integrity of prosthetic assemblies by scanning electron microcopy (SEM). Five Ni-Cr and 10 titanium disks with a diameter of 5 mm and thickness of 3 mm were prepared. DLC coating was applied to five titanium disks. Electrode samples were prepared, and open circuit potential measurements, galvanic current measurements over platinum electrodes, and potentiodynamic polarization tests were carried out. For the SEM evaluation, 20 Ni-Cr alloy and 10 gold alloy superstructures were cast and prepared over 30 abutments. DLC coating was applied to 10 of the abutments. Following the fixation of prosthetic assemblies, the samples were embedded in acrylic resin and cross sectioned longitudinally. Internal fit evaluations were carried out through examination of the SEM images. Titanium showed more noble and electrochemically stable properties than Ni-Cr alloy. DLC coating over the cathode electrode served as an insulating film layer over the surface and prevented galvanic coupling. Results of the SEM evaluations indicated that the DLC-coated and titanium abutments showed no statistically significant difference in fit. Hence, no adverse effects on the adaptation of prosthetic components were found with the application of DLC coating over abutment surfaces. DLC coating might serve as a galvanic corrosion barrier between titanium abutments and Ni-Cr superstructures.

  11. Galvanic element. Galvanisches Element

    Energy Technology Data Exchange (ETDEWEB)

    Sprengel, D.; Haelbig, H.

    1980-01-03

    The invention concerns a gas-tight sealed accumulator with positive and negative electrode plates and an auxillary electrode electroconductively bound to the latter for suppressing oxygen pressure. The auxillary electrode is an intermediate film electrode. The film catalysing oxygen reduction is hydrophilic in character and the other film is hydrophobic. A double coated foil has proved to be advantageous, the hydrophilic film being formed from polymer-bound activated carbon and the hydrophrobic film from porous polytetrafluoroethylene. A metallic network of silver or nickel is rolled into the outer side of the activated carbon film. This auxillary electrode can be used to advantage in all galvanic elements. Even primary cells fall within the scope of application for auxillary electrodes because many of these contain a highly oxidized electrodic material which tends to give off oxygen.

  12. Galvanizing industry: evaluation of exposure levels using biomonitors

    Energy Technology Data Exchange (ETDEWEB)

    Menezes, Maria Angela de B.C.; Sabino, Claudia de V.S.; Amaral, Angela Maria [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil); Mattos, Silvania V. de M. [FUNED, Belo Horizonte, MG (Brazil). Div. de Bromatologia e Toxicologia; S. Filho, Serafim [Secretaria Municipal de Saude de Belo Horizonte, MG (Brazil). Coordenacao de Saude do Trabalhador; Maia, Elene Cristina P. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Dept. de Quimica

    1999-11-01

    In Brazil, statistical surveys concerning occupational diseases refer to accidents and damages. The surveys do not refer to the occupational diseases developed through long exposures to hazardous work conditions, involving physical risk and toxic chemical substances. The Program of Medical Control of Occupational Health determines the Maximum Biological Levels Allowed and the Values of Normality References. But concerning metal and toxic inorganic, values of only few elements are established. In Belo Horizonte and surroundings areas, which is an important industrial centre in the country, there are different industries distributed over various areas. There are about 80 galvanizing industries which are responsible for the majority of the metal contamination hospitalities. A preliminary sampling was performed in order to conduct a survey of the exposures to elements related to occupational diseases in galvanizing industry. The preliminary results for toxic and non-toxic elements obtained using hair and fingernails as biomonitors are shown. The K{sub 0} parametric neutron activation analysis method was applied and the elements determined were: Ag, Al, Au, Cl, Co, Cr, Cu, Fe, I, Mn, Na, Ti, V, Ta, and Zn. (author) 8 refs., 3 figs., 2 tabs.; e-mail: menezes at urano.cdtn.br

  13. A case study of an erosion control practice: the broad-based dip

    Science.gov (United States)

    Kevin Bold; Pamela Edwards; Karl Williard

    2007-01-01

    In 2006, 19 gravel haul roads with broad-based dips within the Monongahela National Forest were examined to determine if those dips adhered to Forest specifications for cut depth and dip outslope. Data on the azimuth, contributing road lengths, slopes of the contributing lengths, landscape position of the dip, and soil texture of the road bed materials also were...

  14. Is galvanic corrosion between titanium alloy and stainless steel spinal implants a clinical concern?

    Science.gov (United States)

    Serhan, Hassan; Slivka, Michael; Albert, Todd; Kwak, S Daniel

    2004-01-01

    Surgeons are hesitant to mix components made of differing metal classes for fear of galvanic corrosion complications. However, in vitro studies have failed to show a significant potential for galvanic corrosion between titanium and stainless steel, the two primary metallic alloys used for spinal implants. Galvanic corrosion resulting from metal mixing has not been described in the literature for spinal implant systems. To determine whether galvanic potential significantly affects in vitro corrosion of titanium and stainless steel spinal implant components during cyclical compression bending. Bilateral spinal implant constructs consisting of pedicle screws, slotted connectors, 6.35-mm diameter rods and a transverse rod connector assembled in polyethylene test blocks were tested in vitro. Two constructs had stainless steel rods with mixed stainless steel (SS-SS) and titanium (SS-Ti) components, and two constructs had titanium rods with mixed stainless steel (Ti-SS) and titanium (Ti-Ti) components. Each construct was immersed in phosphate-buffered saline (pH 7.4) at 37 C and tested in cyclic compression bending using a sinusoidal load-controlling function with a peak load of 300 N and a frequency of 5 Hz until a level of 5 million cycles was reached. The samples were then removed and analyzed visually for evidence of corrosion. In addition, scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) were used to evaluate the extent of corrosion at the interconnections. None of the constructs failed during testing. Gross observation of the implant components after disassembly revealed that no corrosion had occurred on the surface of the implants that had not been in contact with another component. The Ti-Ti interfaces showed some minor signs of corrosion only detectable using SEM and EDS. The greatest amount of corrosion occurred at the SS-SS interfaces and was qualitatively less at the SS-Ti and Ti-SS interfaces. The results from this study indicate

  15. Reduction of teat skin mastitis pathogen loads: differences between strains, dips, and contact times.

    Science.gov (United States)

    Enger, B D; Fox, L K; Gay, J M; Johnson, K A

    2015-02-01

    The purpose of these experiments was to (1) assess differences in mastitis pathogen strain sensitivities to teat disinfectants (teat dips), and (2) determine the optimum time for premilking teat dips to remain in contact with teat skin to reduce pathogen loads on teat skin. Two experiments were conducted using the excised teat model. In experiment 1, the differences in mastitis pathogen strain sensitivities to 4 commercially available dips (dip A: 1% H2O2; dip B: 1% chlorine dioxide; dip C: 1% iodophor; and dip D: 0.5% iodophor) were evaluated. Four strains of 11 common mastitis pathogens (Staphylococcus aureus, Streptococcus agalactiae, Mycoplasma bovis, Streptococcus dysgalactiae, Streptococcus uberis, Escherichia coli, Staphylococcus chromogenes, Staphylococcus epidermidis, Staphylococcus hyicus, Staphylococcus xylosus, and Staphylococcus haemolyticus) were tested. In experiment 2, the percentage log reduction of mastitis pathogens (Escherichia coli, Streptococcus uberis, Streptococcus dysgalactiae, Klebsiella species, Staphylococcus chromogenes, Staphylococcus haemolyticus, Staphylococcus xylosus, and Staphylococcus epidermidis) on teat skin with 3 commercially available teat dips: dip A; dip D; and dip E: 0.25% iodophor, using dip contact times of 15, 30, and 45 s, was evaluated. Experiment 1 results indicated significant differences in strain sensitivities to dips within pathogen species: Staphylococcus aureus, Staphylococcus chromogenes, and Streptococcus uberis. Species differences were also found where Mycoplasma bovis (97.9% log reduction) was the most sensitive to tested teat dips and Staphylococcus haemolyticus (71.4% log reduction) the most resistant. Experiment 2 results indicated that contact times of 30 and 45 s were equally effective in reducing recovered bacteria for dips D and E and were also significantly more effective than a 15-s contact time. No differences were seen in recovered bacteria between tested contact times after treatment with dip

  16. Galvanic corrosion of copper-cast iron couples in relation to the Swedish radioactive waste canister concept

    International Nuclear Information System (INIS)

    Smart, N.R.; Fennell, P.A.H.; Rance, A.P.; Werme, L.O.

    2004-01-01

    To ensure the safe encapsulation of spent nuclear fuel rods for geological disposal, SKB are considering using the Copper-Iron Canister, which consists of an outer copper canister and an inner cast iron container. The canister will be placed into boreholes in the bedrock of a geologic repository and surrounded by bentonite clay. In the unlikely event of the outer copper canister being breached, water could enter the annulus between the inner and outer canister and at points of contact between the two metals there would be a possibility of galvanic interactions. To study this effect, copper-cast iron galvanic couples were set up in a number of different environments representing possible conditions in the SKB repository. The tests investigated two artificial pore-waters and a bentonite slurry, under aerated and deaerated conditions, at 30 deg. C and 50 deg. C. The currents passing between the coupled electrodes and the potential of the couples were monitored for several months. In addition, some bimetallic crevice specimens based on the multi-crevice assembly (MCA) design were used to simulate the situation where the copper canister will be in direct contact with the cast iron inner vessel. The effect of growing an oxide film on the surface of the cast iron prior to coupling it with copper was also investigated. The electrochemical results are presented graphically in the form of electrode potentials and galvanic corrosion currents as a function of time. The galvanic currents in aerated conditions were much higher than in deaerated conditions. For example, at 30 deg. C, galvanic corrosion rates as low as 0.02 μm/year were observed for iron in groundwater after de-aeration, but of the order of 100 μm/year for the cast iron at 50 deg. C in the presence of oxygen. The galvanic currents were generally higher at 50 deg. C than at 30 deg. C. None of the MCA specimens exhibited any signs of crevice corrosion under deaerated conditions. It will be shown that in deaerated

  17. Corrosion control of galvanized steel using a phosphate/calcium ion inhibitor mixture

    International Nuclear Information System (INIS)

    Zin, I.M.; Lyon, S.B.; Pokhmurskii, V.I.

    2003-01-01

    The corrosion inhibition of galvanized steel was studied in artificial acid rain solution using extracts of pigments normally used in organic coatings for corrosion control. It was established that a combination of zinc phosphate/molybdate and calcium ion exchange silica has a significant synergetic anticorrosion effect in the acid rain solution compared to the pigments used alone. Further, the charge transfer resistance of galvanized steel in acid rain solution saturated by the above pigment blend approaches that of strontium chromate in artificial acid rain solution. Use of the pigment blend was found to lead to development of a protective film, which is thought to be a complex mixture of calcium phosphates and zinc phosphate

  18. Prevention of Crevice Corrosion of STS 304 Stainless Steel by a Mg-alloy Galvanic Anode

    International Nuclear Information System (INIS)

    Lim, U. J.; Yun, B. D.; Kim, J. J.

    2006-01-01

    Prevention of crevice corrosion was studied for STS 304 stainless steel using a Mg-alloy galvanic anode in solutions with various specific resistivity. The crevice corrosion and corrosion protection characteristics of the steel was investigated by the electrochemical polarization and galvanic corrosion tests. Experimental results show that the crevice corrosion of STS 304 stainless steel does not occur in solutions of high specific resistivity, but it occurs in solutions of low specific resistivity like in solutions with resistivities of 30, 60 and 115 Ω · m. With decreasing specific resistivity of the solution, the electrode potential of STS 304 stainless steel in the crevice is lowered. The potential of STS 304 stainless steel in the crevice after coupling is cathodically polarized more by decreasing specific resistivity indicating that the crevice corrosion of STS 304 stainless steel is prevented by the Mg-alloy galvanic anode

  19. Controlled Growth of Ultrathin Film of Organic Semiconductors by Balancing the Competitive Processes in Dip-Coating for Organic Transistors.

    Science.gov (United States)

    Wu, Kunjie; Li, Hongwei; Li, Liqiang; Zhang, Suna; Chen, Xiaosong; Xu, Zeyang; Zhang, Xi; Hu, Wenping; Chi, Lifeng; Gao, Xike; Meng, Yancheng

    2016-06-28

    Ultrathin film with thickness below 15 nm of organic semiconductors provides excellent platform for some fundamental research and practical applications in the field of organic electronics. However, it is quite challenging to develop a general principle for the growth of uniform and continuous ultrathin film over large area. Dip-coating is a useful technique to prepare diverse structures of organic semiconductors, but the assembly of organic semiconductors in dip-coating is quite complicated, and there are no reports about the core rules for the growth of ultrathin film via dip-coating until now. In this work, we develop a general strategy for the growth of ultrathin film of organic semiconductor via dip-coating, which provides a relatively facile model to analyze the growth behavior. The balance between the three direct factors (nucleation rate, assembly rate, and recession rate) is the key to determine the growth of ultrathin film. Under the direction of this rule, ultrathin films of four organic semiconductors are obtained. The field-effect transistors constructed on the ultrathin film show good field-effect property. This work provides a general principle and systematic guideline to prepare ultrathin film of organic semiconductors via dip-coating, which would be highly meaningful for organic electronics as well as for the assembly of other materials via solution processes.

  20. Reprocessing of zinc galvanic waste sludge by selective precipitation

    Czech Academy of Sciences Publication Activity Database

    Jandová, J.; Maixner, J.; Grygar, Tomáš

    2002-01-01

    Roč. 46, č. 2 (2002), s. 52-55 ISSN 0862-5468 R&D Projects: GA AV ČR IBS4032004; GA ČR GA203/99/0067 Institutional research plan: CEZ:AV0Z4032918; CEZ:MSM 223100002 Keywords : galvanic sludge * recovery * zinc Subject RIV: CA - Inorganic Chemistry Impact factor: 0.354, year: 2002

  1. Corrosion of bare and galvanized steel in gypsum

    Directory of Open Access Journals (Sweden)

    Gómez, Mercedes

    1988-12-01

    Full Text Available Gypsum is a relatively low-cost building material much abounding in our country. When it is put in contact with steel, it may produce high corrosion rates due to its pH value (close to 7. This work reports the results obtained in studying the corrosion rates of bare and galvanized steel in contact with gypsum and plaster, as well as the influence curing thermal treatment applied to gypsum, enviromental relative humidity and addition of compounds with different natures and purposes may have in such process. In-situ observations, as well as the measurement of the Polarization Resistance and the weight loss have been used as measurement technics. From the results obtained it has been possible to deduce that galvanized steel has better behaviour in dry enviroments than bare steel in the same conditions and moist atmosphere induces proportionally more corrosion in galvanized steel than in bare one. Additions to gypsum do not modified these conclusions, though it may be pointed out that addition of nitrites or lime improves the behaviour of bare steel, while galvanized behaviour is not modified. The addition of lime is not recommended because phenomena of dilated along time expansion may take place.

    El yeso es un material de construcción de relativo bajo coste y que, además, es muy abundante en nuestro país. Debido a su pH cercano a la neutralidad, cuando entra en contacto con el acero, este puede corroerse a elevadas velocidades. En esta comunicación se presentan los resultados de un estudio sobre la velocidad de corrosión del acero desnudo y galvanizado en contacto con yeso y escayola y la influencia que tienen: el tratamiento térmico del curado del yeso, la humedad relativa ambiental y la adición de aditivos de diversa naturaleza y finalidad. Como técnicas de medida se han utilizado la medida de la Resistencia de Polarización y de la pérdida de peso, así como observaciones visuales. De los resultados se puede deducir que en

  2. Numerical analysis of weld pool for galvanized steel with lap joint in GTAW

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hunchul; Park, Kyungbae; Kim, Yougjun; Cho, Jungho [Chungbuk National University, Cheongju (Korea, Republic of); Kim, Dong-Yoon; Kang, Moon-Jin [Korea Institute of Industrial Technology, Incheon (Korea, Republic of)

    2017-06-15

    Galvanized steel is widely used and its demand is growing in automotive industry due to high quality requirement for corrosion resistance. Although there are a lot of demands on using galvanized steel as automotive parts especially for outer body, it has a grave flaw in its welding process. The difficulty is low weldability due to various defects such as porosities and blow holes in weldment, which occurred during welding. A solution to prevent these defects is using hybrid welding process, with two more welding processes. One of the hybrid solutions is using Gas tungsten arc welding (GTAW) as leading position in order to remove the zinc (Zn) coating on the surface before the followed practical fusion welding process. In this research, a numerical analysis model which can predict the eliminated Zn coated layers and the area of Fusion zone (FZ). Developed numerical analysis model was validated through comparing experiment to simulation. Basically, arc heat flux, arc pressure, electromagnetic force and Marangoni flow were employed as the boundary conditions and body force terms. Governing equations such as the continuity, momentum, Volume of fluid (VOF) and energy equations were adopted as usual. In addition to previous model, concentrated arc heat flux and contact thermal conductance models are newly suggested and showed successful result. They are adopted to realize edge concentrated arc and interfacial thermal conductance in lap joint fillet arc welding. Developed numerical analysis model successfully simulated the weld pool and temperature profile therefore the predicted Zn removed area considerably coincided with experimental result.

  3. Numerical analysis of weld pool for galvanized steel with lap joint in GTAW

    International Nuclear Information System (INIS)

    Jeong, Hunchul; Park, Kyungbae; Kim, Yougjun; Cho, Jungho; Kim, Dong-Yoon; Kang, Moon-Jin

    2017-01-01

    Galvanized steel is widely used and its demand is growing in automotive industry due to high quality requirement for corrosion resistance. Although there are a lot of demands on using galvanized steel as automotive parts especially for outer body, it has a grave flaw in its welding process. The difficulty is low weldability due to various defects such as porosities and blow holes in weldment, which occurred during welding. A solution to prevent these defects is using hybrid welding process, with two more welding processes. One of the hybrid solutions is using Gas tungsten arc welding (GTAW) as leading position in order to remove the zinc (Zn) coating on the surface before the followed practical fusion welding process. In this research, a numerical analysis model which can predict the eliminated Zn coated layers and the area of Fusion zone (FZ). Developed numerical analysis model was validated through comparing experiment to simulation. Basically, arc heat flux, arc pressure, electromagnetic force and Marangoni flow were employed as the boundary conditions and body force terms. Governing equations such as the continuity, momentum, Volume of fluid (VOF) and energy equations were adopted as usual. In addition to previous model, concentrated arc heat flux and contact thermal conductance models are newly suggested and showed successful result. They are adopted to realize edge concentrated arc and interfacial thermal conductance in lap joint fillet arc welding. Developed numerical analysis model successfully simulated the weld pool and temperature profile therefore the predicted Zn removed area considerably coincided with experimental result.

  4. Exposure testing of fasteners in preservative treated wood: Gravimetric corrosion rates and corrosion product analyses

    Energy Technology Data Exchange (ETDEWEB)

    Zelinka, Samuel L., E-mail: szelinka@fs.fed.u [USDA Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI 53726 (United States); Sichel, Rebecca J. [College of Engineering, University of Wisconsin, Madison, WI 53706 (United States); Stone, Donald S. [Department of Materials Science and Engineering, College of Engineering, University of Wisconsin, Madison, WI 53706 (United States)

    2010-12-15

    Research highlights: {yields} The composition of the corrosion products was similar for the nail head and shank. {yields} Reduced copper was not detected on any of the fasteners. {yields} Measured corrosion rates were between 1 and 35 {mu}m year{sup -1}. - Abstract: Research was conducted to determine the corrosion rates of metals in preservative treated wood and also understand the mechanism of metal corrosion in treated wood. Steel and hot-dip galvanized steel fasteners were embedded in wood treated with one of six preservative treatments and exposed to 27 {sup o}C at 100% relative humidity for 1 year. The corrosion rate was determined gravimetrically and the corrosion products were analyzed with scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. Although the accepted mechanism of corrosion in treated wood involves the reduction of cupric ions from the wood preservative, no reduced copper was found on the corrosion surfaces. The galvanized corrosion products contained sulfates, whereas the steel corrosion products consisted of iron oxides and hydroxides. The possible implications and limitations of this research on fasteners used in building applications are discussed.

  5. Setup of Galvanic Sensors for the Monitoring of Gilded Bronzes

    Directory of Open Access Journals (Sweden)

    Sara Goidanich

    2014-04-01

    Full Text Available Traditional electrochemical techniques, such as linear polarization resistance (Rp, and electrochemical impedance spectroscopy (EIS, cannot be applied to gilded bronzes, as it may not be possible to interpret the results obtained due to the bimetallic nature of the studied material. The measurement of the macrocouple current generated by the gold/bronze galvanic couple can be used as an indicator of degradation processes. Nevertheless, this measurement cannot be performed directly on the original artifacts due to the systematic presence of short-circuits between the two metals. In the present work the use of galvanic sensors is proposed as a possible solution for the monitoring of gilded bronze artefacts. The sensors have been designed to simulate real gilded bronze surfaces in terms of composition and stratigraphy and have proved to be a reliable diagnostic tool for the in situ monitoring of the rates of deterioration of gilded bronze surfaces and to test new conservation treatments. Their set-up and application is reported and their performances discussed.

  6. Fire tests to study heat insulation scenario of galvanized rolling shutters sprayed with intumescent coatings

    International Nuclear Information System (INIS)

    Chuang, Ying-Ji; Chuang, Ying-Hung; Lin, Ching-Yuan

    2009-01-01

    The purpose of this study, through standard furnace fire tests and a natural fire test, is to analyze the heat insulation behavior of galvanized rolling shutters sprayed with intumescent coatings. The following experiments and associated estimations demonstrated that in the 1-h standard fire-resisting tests, the radiant heat flux at a measuring point horizontally 1 m away from the center of an unexposed surface the radiation could reach 4.64 W/cm 2 for the traditional uninsulated galvanized rolling shutter, and that the radiant heat flux would be substantially decreased to 0.22 W/cm 2 for one with intumescent coating of 0.3 mm target thickness, which, during the heating process, expanded about 100 times in volume and then generated a certain insulation effect. Therefore the intumescent coatings on galvanized rolling shutters have been proved by this study to be a feasible method of insulation, which can be applied in the future fire compartment design of buildings.

  7. Galvanic Interaction between Chalcopyrite and Pyrite with Low Alloy and High Carbon Chromium Steel Ball

    Directory of Open Access Journals (Sweden)

    Asghar Azizi

    2013-01-01

    Full Text Available This study was aimed to investigate the galvanic interaction between pyrite and chalcopyrite with two types of grinding media (low alloy and high carbon chromium steel ball in grinding of a porphyry copper sulphide ore. Results indicated that injection of different gases into mill altered the oxidation-reduction environment during grinding. High carbon chromium steel ball under nitrogen gas has the lowest galvanic current, and low alloy steel ball under oxygen gas had the highest galvanic current. Also, results showed that the media is anodic relative to pyrite and chalcopyrite, and therefore pyrite or chalcopyrite with a higher rest potential acted as the cathode, whilst the grinding media with a lower rest potential acted as the anode, when they are electrochemically contacted. It was also found that low alloy steel under oxygen produced the highest amount of EDTA extractable iron in the slurry, whilst high carbon chromium steel under nitrogen atmosphere led to the lowest amount.

  8. Galvanic Vestibular Stimulation (GVS) as an Analogue of Post-flight Sensorimotor Dysfunction

    Data.gov (United States)

    National Aeronautics and Space Administration — Aim 1A (complete): Tolerance to GVS. Dilda, V, MacDougall HG, Moore, ST. Tolerance to extended Galvanic vestibular stimulation: optimal exposure for astronaut...

  9. Deformation modeling and the strain transient dip test

    International Nuclear Information System (INIS)

    Jones, W.B.; Rohde, R.W.; Swearengen, J.C.

    1980-01-01

    Recent efforts in material deformation modeling reveal a trend toward unifying creep and plasticity with a single rate-dependent formulation. While such models can describe actual material deformation, most require a number of different experiments to generate model parameter information. Recently, however, a new model has been proposed in which most of the requisite constants may be found by examining creep transients brought about through abrupt changes in creep stress (strain transient dip test). The critical measurement in this test is the absence of a resolvable creep rate after a stress drop. As a consequence, the result is extraordinarily sensitive to strain resolution as well as machine mechanical response. This paper presents the design of a machine in which these spurious effects have been minimized and discusses the nature of the strain transient dip test using the example of aluminum. It is concluded that the strain transient dip test is not useful as the primary test for verifying any micromechanical model of deformation. Nevertheless, if a model can be developed which is verifiable by other experimentts, data from a dip test machine may be used to generate model parameters

  10. Galvanic microparticles increase migration of human dermal fibroblasts in a wound-healing model via reactive oxygen species pathway.

    Science.gov (United States)

    Tandon, Nina; Cimetta, Elisa; Villasante, Aranzazu; Kupferstein, Nicolette; Southall, Michael D; Fassih, Ali; Xie, Junxia; Sun, Ying; Vunjak-Novakovic, Gordana

    2014-01-01

    Electrical signals have been implied in many biological mechanisms, including wound healing, which has been associated with transient electrical currents not present in intact skin. One method to generate electrical signals similar to those naturally occurring in wounds is by supplementation of galvanic particles dispersed in a cream or gel. We constructed a three-layered model of skin consisting of human dermal fibroblasts in hydrogel (mimic of dermis), a hydrogel barrier layer (mimic of epidermis) and galvanic microparticles in hydrogel (mimic of a cream containing galvanic particles applied to skin). Using this model, we investigated the effects of the properties and amounts of Cu/Zn galvanic particles on adult human dermal fibroblasts in terms of the speed of wound closing and gene expression. The collected data suggest that the effects on wound closing are due to the ROS-mediated enhancement of fibroblast migration, which is in turn mediated by the BMP/SMAD signaling pathway. These results imply that topical low-grade electric currents via microparticles could enhance wound healing. © 2013 Elsevier Inc. All rights reserved.

  11. Protocol for the microbial degradation of coumaphos from cattle dip

    International Nuclear Information System (INIS)

    Mulbry, W.; Karns, J.

    1997-01-01

    Insecticide wastes generated from livestock dipping operations are well suited for biodegradation processes since these wastes are concentrated, contained, and have no other significant toxic components. About 400,000 L of cattle dip wastes containing approximately 1500 mg/L of the organophosphate coumaphos are generated yearly along the Mexican border from a USDA program designed to control disease carrying cattle ticks. Use of unlined evaporation pits for the disposal of these wastes has resulted in highly contaminated soils underlying these sites. Previous work has shown that microbial consortia present in selected dip wastes can be induced to mineralize coumaphos. Our laboratory results show that these consortia are able to colonize plastic fibers in trickling biofilters and can be used in these filters to quickly metabolize coumaphos from dip wastes. A field scale biofilter capable of treating 15,000 litre batches of dip waste was used to reduce the coumaphos concentration in two successive 11,000 litre batch trials from 2000 mg/L to 10 mg/L in approximately 14 d. (author)

  12. Effect of UV-C radiation and hot water on the calcium content and postharvest quality of apples

    Energy Technology Data Exchange (ETDEWEB)

    Hemmaty, S.; Moallemi, N.; Naseri, L.

    2007-12-15

    To increase the storage shelf life of 'Red Delicious' and 'Golden Delicious' apples they were treated with UV-C irradiation at doses of 0, 5 and 15 min irradiation at 1.435 x 10{sup -4} W/square cm{sup -} and with hot water containing 4% CaCl{sub 2} at four levels (control, dipping at 25 deg C for 10 min, dipping at 38 deg C for 5 min and dipping in 54 deg C for 1 min) in a factorial design with 4 replicates. The results showed that UV-C irradiation and dipping of fruit in hot water increased the storage life and improved fruit quality factors in 'Red Delicious' and 'Golden Delicious' apples at the end of cold storage. Both UV-C and hot water treatments decreased pH and total soluble solids/titratable acids ratio and increased fruit titratable acids and firmness. UV-C and hot water treatment increased fruit Ca content during storage. The results showed that UV-C and hot water treatment can retard fruit ripening and maintain fruit quality in cold storage. These treatments can also increase Ca concentration of fruit flesh and thus increase the nutritional value of the apples. (author) [Spanish] Con el fin de prolongar el periodo de vida útil durante la conservación frigorífica de manzanas ‘Red Delicious’ y ‘Golden Delicious’, éstas se trataron con radiación UV-C en tres dosis (0, 5 y 15 min de irradiación a 1,435 × 10{sup -4} W cm{sup -2}) y agua caliente con CaCl{sub 2} al 4% en cuatro niveles (control 0, inmersión a 25°C 10 min, 38°C 5 min ó 54°C 1 min), en un diseño factorial con 4 repeticiones por tratamiento. La irradiación con UV-C y la inmersión de los frutos en agua caliente permitió alargar el periodo de conservación y mejoró la calidad de manzanas ‘Red Delicious’ y ‘Golden Delicious’ tras el almacenamiento en frío. Ambos tratamientos aumentaron la acidez titulable y la firmeza de los frutos, también disminuyeron el pH y la relación sólidos solubles/acidez. El tratamiento con UV-C y agua caliente incrementó el contenido

  13. 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

  14. Comparison of Galvanic Currents Generated Between Different Combinations of Orthodontic Brackets and Archwires Using Potentiostat: An In Vitro Study.

    Science.gov (United States)

    Nayak, Rabindra S; Shafiuddin, Bareera; Pasha, Azam; Vinay, K; Narayan, Anjali; Shetty, Smitha V

    2015-07-01

    Technological advances in wire selection and bracket design have led to improved treatment efficiency and allowed longer time intervals between appliance adjustments. The wires remain in the mouth for a longer duration and are subjected to electrochemical reactions, mechanical forces of mastication and generalized wear. These cause different types of corrosion. This study was done to compare the galvanic currents generated between different combinations of brackets and archwires commonly used in orthodontic practices. The materials used for the study included different commercially available orthodontic archwires and brackets. The galvanic current generated by individual materials and different combinations of these materials was tested and compared. The orthodontic archwires used were 0.019″ × 0.025″ heat-activated nickel-titanium (3M Unitek), 0.019″ × 0.025″ beta-titanium (3M Unitek) and 0.019″ × 0.025″ stainless steel (3M Unitek). The orthodontic brackets used were 0.022″ MBT laser-cut (Victory Series, 3M Unitek) and metal-injection molded (Leone Company) maxillary central incisor brackets respectively. The ligature wire used for ligation was 0.009″ stainless steel ligature (HP Company). The galvanic current for individual archwires, brackets, and the different bracket-archwire-ligature combinations was measured by using a Potentiostat machine. The data were generated using the Linear Sweep Voltammetry and OriginPro 8.5 Graphing and Data Analysis Softwares. The study was conducted in two phases. Phase I comprised of five groups for open circuit potential (OCP) and galvanic current (I), whereas Phase II comprised of six groups for galvanic current alone. Mean, standard deviation and range were computed for the OCP and galvanic current (I) values obtained. Results were subjected to statistical analysis through ANOVA. In Phase I, higher mean OCP was recorded in stainless steel archwire, followed by beta-titanium archwire, heat-activated nickel

  15. Intracavity OptoGalvanic Spectroscopy Not Suitable for Ambient Level Radiocarbon Detection

    NARCIS (Netherlands)

    Paul, Dipayan; Meijer, Harro

    2015-01-01

    IntraCavity OptoGalvanic Spectroscopy as a radiocarbon detection technique was first reported by the Murnick group at Rutgers University, Newark, NJ, in 2008. This technique for radiocarbon detection was presented with tremendous potentials for applications in various fields of research.

  16. Continuous distillation of bituminous shale. [hot gas in chamber and chamber heated externally

    Energy Technology Data Exchange (ETDEWEB)

    1921-04-27

    A process of continuous distillation of bituminous shale is given in which the heat necessary is produced not only on the exterior but also in the interior of the distillation apparatus in the form of hot gas directly bathing the shale. The residual carbon in the shale after distillation, or maybe with other fuel added to it, can be utilized; the fuel may be utilized not only for the heat it furnishes but also for the gas it gives and which adds itself to the incondensable gas from the distillation. The temperature of the zone of distillation of the shale is regulated by the quantity of gas, the temperature of this gas (which can be lowered voluntarily by injecting into the air a certain quantity of water vapor), the length of the zone comprised between the zone of gasification and distillation; the injection of water vapor permits the recovery of part of the nitrogen of the shale in the form of ammonia; the materials are withdrawn continuously in a mechanical way.

  17. Galvanic deposition and characterization of brushite/hydroxyapatite coatings on 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Blanda, Giuseppe [Laboratorio di Chimica Fisica Applicata, Dipartimento di Ingegneria Chimica Gestionale Informatica Meccanica, Università di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Brucato, Valerio; Pavia, Francesco Carfì; Greco, Silvia [Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali, Università di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Piazza, Salvatore; Sunseri, Carmelo [Laboratorio di Chimica Fisica Applicata, Dipartimento di Ingegneria Chimica Gestionale Informatica Meccanica, Università di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Inguanta, Rosalinda, E-mail: rosalinda.inguanta@unipa.it [Laboratorio di Chimica Fisica Applicata, Dipartimento di Ingegneria Chimica Gestionale Informatica Meccanica, Università di Palermo, Viale delle Scienze, 90128 Palermo (Italy)

    2016-07-01

    In this work, brushite and brushite/hydroxyapatite (BS, CaHPO{sub 4}·H{sub 2}O; HA, Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}) coatings were deposited on 316L stainless steel (316LSS) from a solution containing Ca(NO{sub 3}){sub 2}·4H{sub 2}O and NH{sub 4}H{sub 2}PO{sub 4} by a displacement reaction based on a galvanic contact, where zinc acts as sacrificial anode. Driving force for the cementation reaction arises from the difference in the electrochemical standard potentials of two different metallic materials (316LSS and Zn) immersed in an electrolyte, so forming a galvanic contact leading to the deposition of BS/HA on nobler metal. We found that temperature and deposition time affect coating features (morphology, structure, and composition). Deposits were characterized by means of several techniques. The morphology was investigated by scanning electron microscopy, the elemental composition was obtained by X-ray energy dispersive spectroscopy, whilst the structure was identified by Raman spectroscopy and X-ray diffraction. BS was deposited at all investigated temperatures covering the 316LSS surface. At low and moderate temperature, BS coatings were compact, uniform and with good crystalline degree. On BS layers, HA crystals were obtained at 50 °C for all deposition times, while at 25 °C, its presence was revealed only after long deposition time. Electrochemical studies show remarkable improvement in corrosion resistance. - Highlights: • Brushite/hydroxyapatite coatings were obtained by a galvanic deposition method. • Galvanic deposition is simple and cheap and does not require external power supply. • Temperature is a key parameter to control composition and morphology of coatings. • Ca/P ratio changes with deposition time, from about 1 up to an optimum value of 1.7. • Compact and adherent layer covering substrate surface were obtained on 316LSS.

  18. Galvanic deposition and characterization of brushite/hydroxyapatite coatings on 316L stainless steel

    International Nuclear Information System (INIS)

    Blanda, Giuseppe; Brucato, Valerio; Pavia, Francesco Carfì; Greco, Silvia; Piazza, Salvatore; Sunseri, Carmelo; Inguanta, Rosalinda

    2016-01-01

    In this work, brushite and brushite/hydroxyapatite (BS, CaHPO_4·H_2O; HA, Ca_1_0(PO_4)_6(OH)_2) coatings were deposited on 316L stainless steel (316LSS) from a solution containing Ca(NO_3)_2·4H_2O and NH_4H_2PO_4 by a displacement reaction based on a galvanic contact, where zinc acts as sacrificial anode. Driving force for the cementation reaction arises from the difference in the electrochemical standard potentials of two different metallic materials (316LSS and Zn) immersed in an electrolyte, so forming a galvanic contact leading to the deposition of BS/HA on nobler metal. We found that temperature and deposition time affect coating features (morphology, structure, and composition). Deposits were characterized by means of several techniques. The morphology was investigated by scanning electron microscopy, the elemental composition was obtained by X-ray energy dispersive spectroscopy, whilst the structure was identified by Raman spectroscopy and X-ray diffraction. BS was deposited at all investigated temperatures covering the 316LSS surface. At low and moderate temperature, BS coatings were compact, uniform and with good crystalline degree. On BS layers, HA crystals were obtained at 50 °C for all deposition times, while at 25 °C, its presence was revealed only after long deposition time. Electrochemical studies show remarkable improvement in corrosion resistance. - Highlights: • Brushite/hydroxyapatite coatings were obtained by a galvanic deposition method. • Galvanic deposition is simple and cheap and does not require external power supply. • Temperature is a key parameter to control composition and morphology of coatings. • Ca/P ratio changes with deposition time, from about 1 up to an optimum value of 1.7. • Compact and adherent layer covering substrate surface were obtained on 316LSS.

  19. Factores que afectan a la estructura de los recubrimientos de cinc obtenidos por inmersión

    Directory of Open Access Journals (Sweden)

    Seré, P. R.

    1997-12-01

    Full Text Available Coating solidification during hot-dip galvanizing is a very complex process due to Al-Fe, Al-Fe-Zn and Fe-Zn intermetallic compounds development. Fe-Zn intermetallic are brittle and detrimental for the coating ductility, while the diffusion towards the surface of a segregated insoluble alloying such as antimonium causes the sheet darkness. Steel sheets of different roughness were hot-dip galvanized under different operation conditions using a laboratory scale simulator. The effect of steel roughness and process parameters upon coating characteristics were analyzed. Experimental results showed that the steel roughness affects the coating thickness, zinc grain size and texture as well as the out-bursts development, while the process parameters affects the Fe2Al5 morphology and antimonium segregation.

    En el proceso de galvanizado por inmersión, la solidificación del recubrimiento constituye una etapa compleja en la que, además de formarse compuestos intermetálicos de Al-Fe, Al-Fe-Zn y Fe-Zn, tiene lugar la segregación de elementos aleantes insolubles como el antimonio. Ambos fenómenos son, al menos parcialmente, indeseables ya que la fragilidad de los intermetálicos de Fe-Zn afecta a la ductilidad del recubrimiento y la difusión del antimonio hacia la superficie causa su ennegrecimiento. Con un simulador diseñado a escala de laboratorio se galvanizaron chapas de diferente rugosidad sujetas a condiciones operativas también diferentes, analizándose el efecto de la rugosidad del acero y de los parámetros del proceso sobre las características del recubrimiento. Los resultados obtenidos demostraron que la rugosidad afecta tanto al espesor del recubrimiento, tamaño de grano y textura del cinc como a la formación de out-bursts, mientras que los parámetros del proceso lo hacen sobre la morfología del intermetálico Fe2Al5 y la segregación de antimonio.

  20. Anticorrosive Performance of Zinc Phosphate Coatings on Mild Steel Developed Using Galvanic Coupling

    Directory of Open Access Journals (Sweden)

    M. Arthanareeswari

    2013-01-01

    Full Text Available The anticorrosive performance of zinc phosphate coatings developed by galvanic coupling technique on mild steel substrates using the cathode materials such as titanium (Ti, copper (Cu, brass (BR, nickel (Ni, and stainless steel (SS is elucidated in this study. Thermal and chemical stability tests, immersion test in 3.5% NaCl, ARE salt droplet test, and salt spray test were carried out. The study reveals that the mild steel substrates phosphated under galvanically coupled condition showed better corrosion resistance than the one coated without coupling. The open circuit potential (OCP of phosphated mild steel panels in 3.5% NaCl was found to be a function of phosphate coating weight and porosity of the coating.

  1. In situ 2D maps of pH shifts across brass–lead galvanic joints using microelectrodes

    International Nuclear Information System (INIS)

    Ma, Xiangmeng; Lee, Woo Hyoung; Lytle, Darren A

    2017-01-01

    Galvanic corrosion in drinking water distribution systems, such as conditions following partial lead service line replacement, can be a significant source of lead in tap water. The objective of this work was to measure the pH directly near metal surfaces using a novel experimental tool in order to understand the water chemistry at a lead-containing galvanic couple in drinking water. Specifically, pH microprofiles in the proximity of corroding metal surfaces were measured using a microelectrode to construct detailed in situ 2D spatial maps of the pH across a galvanic couple at 100 µ m above the metal’s surface under flowing and stagnation conditions. The opposite pH trend was directly observed across the galvanic couple under flow and stagnation conditions. Water stagnation resulted in a pH at the anode (leaded solder) of 1.5 pH units lower than the bulk water pH (9.0) and as much as 2.5 pH units lower than the cathode (brass). These conditions can enhance lead release at the anode, which reflects different anodic–cathodic relationships of coupled metals primarily controlled by water flow. Most importantly, this work has demonstrated the ability to make real pH measurement at the surface of corroding metals using a novel microelectrode approach. (paper)

  2. A Facile Fabrication of Silver-Coated Copper Nanowires by Galvanic Replacement

    Directory of Open Access Journals (Sweden)

    Xin He

    2016-01-01

    Full Text Available We demonstrated a general strategy to fabricate silver-coated copper nanowires by a galvanic replacement, which is guided by the chemical principle that metal ions (silver ions with a relatively high reduction potential can galvanically etch nanostructure made from a less metal (copper. Well-dispersed and high-yielded copper nanowires were initially synthesized and then introduced into silver-ammonia solution for the growth of silver nanocrystals on the nanowire surfaces under vigorous oscillation. The results of X-ray diffraction, scanning electron microscope, and transmission electron microscope revealed that the silver nanocrystals were uniformly distributed on the copper nanowire surfaces to form Cu-Ag heterostructures. The concentration of silver-ammonia solution and the time of replacement reaction determine the size and density of the silver nanocrystals. Our investigation might pave the way to the synthesis of other bimetallic nanostructures via a facile, fast, and economical route.

  3. Quantitative influence of minor and impurity elements on hot cracking susceptibility of extra high-purity type 310 stainless steel

    International Nuclear Information System (INIS)

    Saida, Kazuyoshi; Matsushita, Hideki; Nishimoto, Kazutoshi; Kiuchi, Kiyoshi; Nakayama, Junpei

    2013-01-01

    To evaluate the influence of minor and impurity elements such as C, Mn, P and S on the solidification and ductility-dip cracking susceptibilities of extra high-purity type 310 stainless steels, the transverse-Varestraint test was conducted by using several type 310 stainless steels with different amounts of C, Mn, P and S. Two types of hot cracks occurred in these steels by Varestraint test; solidification and ductility-dip cracks. The solidification cracking susceptibility was significantly reduced as the amounts of C, P and S decreased. The ductility-dip cracking susceptibility also reduced with a decrease in P and S contents. It adversely, however, increased as the C content of the steels was reduced. Mn didn't greatly affect the hot cracking susceptibility of the extra high-purity steels. The characteristic influence on solidification cracking was the ratio of P:S:C=1:1.3:0.56, while Mn negligibly ameliorated solidification cracking in the extra low S (and P) steels. The numerical analysis on the solidification brittle temperature range (BTR) revealed that the reduced solidification cracking susceptibility with decreasing the amounts of C, P and S in steel could be attributed to the reduced BTR due to the suppression of solidification segregation of minor and impurity elements in the finally solidified liquid film between dendrites. On the other hand, a molecular orbital analysis to estimate the binding strength of the grain boundary suggested that the increased ductility-dip cracking susceptibility in extra high-purity steels was caused by grain boundary embrittlement due to the refining of beneficial elements for grain boundary strengthening such as C. (author)

  4. Effect of gamma irradiation with or without hot water dip and transportation from Thailand to Canada on nutritional qualities, ripening index and sensorial characteristics of Thai mangoes (Nahng Glahng Wahn variety)

    International Nuclear Information System (INIS)

    Lacroix, M.; Gagnon, M.; Pringsulaka, V.

    1993-01-01

    Mangoes of the Nahng Glahng Wahn variety from Thailand were irradiated at the Thai Irradiation Center (TIC) at 0.49 to 0.77 kGy. One batch was retained in Thailand while the other was shipped to the Canadian Irradiation Center (CIC) for investigation of the same variables during storage, to compare the effects of gamma radiation with hot water dip (HWI) or without (I) before and after transportation on the ripening, vitamin C and vitamin A content and sensory qualities of mangoes. The results indicate that the I and HWI treatments delayed the ripening of the mangoes. The irradiated groups appeared to have a slightly higher content of ascorbic acid on the first day after irradiation than their corresponding controls. The sensory evaluation indicates that the panelists mostly favoured the I and HWI irradiated groups for the overall appearance and texture of whole mangoes and pulp and in taste and palatability of the pulp alone. Transportation stress did not appear to have much effect on the ascorbic acid and dehydroascorbic acid levels and the sensorial tests. The mangoes stored and studied in Canada appeared to have a lower vitamin A content. (author)

  5. Kinetics of atmospheric corrosion of mild steel, zinc, galvanized iron and aluminium at 10 exposure stations in India

    International Nuclear Information System (INIS)

    Natesan, M.; Venkatachari, G.; Palaniswamy, N.

    2006-01-01

    As a part of updating Corrosion Map of India project, atmospheric corrosion behaviour of commercially available engineering materials such as mild steel, galvanized iron, zinc and aluminium metals was studied in marine, industrial, urban, and rural environments by weight loss method at 10 exposure stations in India over a period of 5 years. The results of these studies demonstrated that galvanized iron, zinc and aluminium metals were several times more durable than mild steel. Compared to galvanized iron and zinc, aluminium provided superior protection in industrial and marine environment except at Mormugao Port Trust (MPT). It also offered much better resistance to corrosion in rural environments. At certain places, galvanized iron proved to be more durable than aluminium. The results obeyed well with the empirical kinetics equation of the form C = Kt n , where K and C are the corrosion losses in μm after 1 and 't' years of the exposure, respectively, and 'n' is a constant. Based on 'n' values, the corrosion mechanisms of these metals are predicted. The corrosion products formed on the metal samples in Chennai marine atmosphere were identified by X-ray diffraction analysis

  6. A finite-element simulation of galvanic coupling intra-body communication based on the whole human body.

    Science.gov (United States)

    Song, Yong; Zhang, Kai; Hao, Qun; Hu, Lanxin; Wang, Jingwen; Shang, Fuzhou

    2012-10-09

    Simulation based on the finite-element (FE) method plays an important role in the investigation of intra-body communication (IBC). In this paper, a finite-element model of the whole body model used for the IBC simulation is proposed and verified, while the FE simulation of the galvanic coupling IBC with different signal transmission paths has been achieved. Firstly, a novel finite-element method for modeling the whole human body is proposed, and a FE model of the whole human body used for IBC simulation was developed. Secondly, the simulations of the galvanic coupling IBC with the different signal transmission paths were implemented. Finally, the feasibility of the proposed method was verified by using in vivo measurements within the frequency range of 10 kHz-5 MHz, whereby some important conclusions were deduced. Our results indicate that the proposed method will offer significant advantages in the investigation of the galvanic coupling intra-body communication.

  7. Microscopic creep models and the interpretation of stress-dip tests during creep

    International Nuclear Information System (INIS)

    Poirier, J.P.

    1976-09-01

    A critical analysis is made of the principal divergent view points concerning stress-dip tests. The raw data are examined and interpreted in the light of various creep models. The following problems are discussed: is the reverse strain anelastic or plastic; is the zero creep rate periodic due to recovery or is it spurious; can the existence or inexistence of an internal stress be deduced from stress-dip tests; can stress-dip tests allow to determine whether glide is jerky or viscous; can the internal stress be measured by stress-dip tests

  8. Multiple-Satellite Observation of Magnetic Dip Event During the Substorm on 10 October 2013

    Science.gov (United States)

    He, Zhaoguo; Chen, Lunjin; Zhu, Hui; Xia, Zhiyang; Reeves, G. D.; Xiong, Ying; Xie, Lun; Cao, Yong

    2017-09-01

    We present a multiple-satellite observation of the magnetic dip event during the substorm on 10 October 2013. The observation illustrates the temporal and spatial evolution of the magnetic dip and gives a compelling evidence that ring current ions induce the magnetic dip by enhanced plasma beta. The dip moves with the energetic ions in a comparable drift velocity and affects the dynamics of relativistic electrons in the radiation belt. In addition, the magnetic dip provides a favorable condition for the electromagnetic ion cyclotron (EMIC) wave generation based on the linear theory analysis. The calculated proton diffusion coefficients show that the observed EMIC wave can lead to the pitch angle scattering losses of the ring current ions, which in turn partially relax the magnetic dip in the observations. This study enriches our understanding of magnetic dip evolution and demonstrates the important role of the magnetic dip for the coupling of radiation belt and ring current.

  9. A set of 14 DIP-SNP markers to detect unbalanced DNA mixtures.

    Science.gov (United States)

    Liu, Zhizhen; Liu, Jinding; Wang, Jiaqi; Chen, Deqing; Liu, Zidong; Shi, Jie; Li, Zeqin; Li, Wenyan; Zhang, Gengqian; Du, Bing

    2018-03-04

    Unbalanced DNA mixture is still a difficult problem for forensic practice. DIP-STRs are useful markers for detection of minor DNA but they are not widespread in the human genome and having long amplicons. In this study, we proposed a novel type of genetic marker, termed DIP-SNP. DIP-SNP refers to the combination of INDEL and SNP in less than 300bp length of human genome. The multiplex PCR and SNaPshot assay were established for 14 DIP-SNP markers in a Chinese Han population from Shanxi, China. This novel compound marker allows detection of the minor DNA contributor with sensitivity from 1:50 to 1:1000 in a DNA mixture of any gender with 1 ng-10 ng DNA template. Most of the DIP-SNP markers had a relatively high probability of informative alleles with an average I value of 0.33. In all, we proposed DIP-SNP as a novel kind of genetic marker for detection of minor contributor from unbalanced DNA mixture and established the detection method by associating the multiplex PCR and SNaPshot assay. DIP-SNP polymorphisms are promising markers for forensic or clinical mixture examination because they are shorter, widespread and higher sensitive. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. 29 CFR 1910.126 - Additional requirements for special dipping and coating operations.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Additional requirements for special dipping and coating... Dipping and Coating Operations § 1910.126 Additional requirements for special dipping and coating... requirements apply to flow coating? (1) You must use a direct low-pressure pumping system or a 10-gallon (38 L...

  11. Coulomb explosion of “hot spot”

    Energy Technology Data Exchange (ETDEWEB)

    Oreshkin, V. I., E-mail: oreshkin@ovpe.hcei.tsc.ru [Institute of High Current Electrons, SB, RAS, Tomsk (Russian Federation); Tomsk Polytechnic University, Tomsk (Russian Federation); Oreshkin, E. V. [P. N. Lebedev Physical Institute, RAS, Moscow (Russian Federation); Chaikovsky, S. A. [Institute of High Current Electrons, SB, RAS, Tomsk (Russian Federation); P. N. Lebedev Physical Institute, RAS, Moscow (Russian Federation); Institute of Electrophysics, UD, RAS, Ekaterinburg (Russian Federation); Artyomov, A. P. [Institute of High Current Electrons, SB, RAS, Tomsk (Russian Federation)

    2016-09-15

    The study presented in this paper has shown that the generation of hard x rays and high-energy ions, which are detected in pinch implosion experiments, may be associated with the Coulomb explosion of the hot spot that is formed due to the outflow of the material from the pinch cross point. During the process of material outflow, the temperature of the hot spot plasma increases, and conditions arise for the plasma electrons to become continuously accelerated. The runaway of electrons from the hot spot region results in the buildup of positive space charge in this region followed by a Coulomb explosion. The conditions for the hot spot plasma electrons to become continuously accelerated have been revealed, and the estimates have been obtained for the kinetic energy of the ions generated by the Coulomb explosion.

  12. Coulomb explosion of “hot spot”

    International Nuclear Information System (INIS)

    Oreshkin, V. I.; Oreshkin, E. V.; Chaikovsky, S. A.; Artyomov, A. P.

    2016-01-01

    The study presented in this paper has shown that the generation of hard x rays and high-energy ions, which are detected in pinch implosion experiments, may be associated with the Coulomb explosion of the hot spot that is formed due to the outflow of the material from the pinch cross point. During the process of material outflow, the temperature of the hot spot plasma increases, and conditions arise for the plasma electrons to become continuously accelerated. The runaway of electrons from the hot spot region results in the buildup of positive space charge in this region followed by a Coulomb explosion. The conditions for the hot spot plasma electrons to become continuously accelerated have been revealed, and the estimates have been obtained for the kinetic energy of the ions generated by the Coulomb explosion.

  13. DiPS: A Unifying Approach for developing System Software

    OpenAIRE

    Michiels, Sam; Matthijs, Frank; Walravens, Dirk; Verbaeten, Pierre

    2002-01-01

    In this paper we unify three essential features for flexible system software: a component oriented approach, self-adaptation and separation of concerns.We propose DiPS (Distrinet Protocol Stack), a component framework, which offers components, an anonymous interaction model and connectors to handle non-functional aspects such as concurrency. DiPS has effectively been used in industrial protocol stacks and device drivers.

  14. Immobilization of heavy metals arising sludge galvanic, in glass ceramic material

    International Nuclear Information System (INIS)

    Felisberto, R.; Santos, M.C.; Basegio, T.; Bergmann, C.P.

    2016-01-01

    The use of galvanic sludge in the glass-ceramic formulation for immobilizing environmentally harmful materials is consolidated in more developed countries as raw material in the formulation of new materials. In this work, we have used galvanic sludge provided by a metallurgical company located in Vale dos Sinos, RS. The sludge was dried at 105°C and mixed with soda-lime glass in proportions of 1, 5, 10 and 20%, relative to the glass mass. Its composition was determined by FRX, and evaluated for leaching (NBR 10005) and solubilization (NBR 10006). The specimens (CPs) were burned at temperatures 750, 800 and 850°C, also submitted to the tests. The sludge, Class I - dangerous, presented Se content greater than provisions of NBR 10004. It was possible to immobilize the heavy metals at a temperature of 850°C for specimens of the F1 formulation, having been thus classified as Class II B Inert Residue. (author)

  15. Large-scale synthesis of Tellurium nanostructures via galvanic displacement of metals

    Science.gov (United States)

    Kok, Kuan-Ying; Choo, Thye-Foo; Ubaidah Saidin, Nur; Rahman, Che Zuraini Che Ab

    2018-01-01

    Tellurium (Te) is an attractive semiconductor material for a wide range of applications in various functional devices including, radiation dosimeters, optical storage materials, thermoelectric or piezoelectric generators. In this work, large scale synthesis of tellurium (Te) nanostructures have been successfully carried out in different concentrations of aqueous solutions containing TeO2 and NaOH, by galvanic displacements of Zn and Al which served as the sacrificial materials. Galvanic displacement process is cost-effective and it requires no template or surfactant for the synthesis of nanostructures. By varying the concentrations of TeO2 and NaOH, etching temperatures and etching times, Te nanostructures of various forms of nanostructures were successfully obtained, ranging from one-dimensional needles and rod-like structures to more complex hierarchical structures. Microscopy examinations on the nanostructures obtained have shown that both the diameters and lengths of the Te nanostructures increased with increasing etching temperature and etching time.

  16. Silver matrix composites reinforced with galvanically silvered particles

    OpenAIRE

    J. Śleziona; J. Wieczorek,

    2007-01-01

    Purpose: The paper presents the possibility of the application of metalic layers drifted with the use of the galvanic methods on the ceramic particles surface. The application of the layers was aimed at obtaining the rewetting of the reinforcing particles with the liquid silver in the course of the producing of silver matrix composites with the use of mechanical stirring method. To enable introducing of the iron powder and glass carbon powder to liquid silver the solution of covering the powd...

  17. Trapping dynamics of diindenoperylene (DIP) in self-assembled monolayers using molecular simulation

    KAUST Repository

    Kaushik, Ananth P.

    2011-07-01

    All-atom Molecular Dynamics simulation methods employing a well-tested intermolecular potential model, MM3 (Molecular Mechanics 3), demonstrate the propensity for diindenoperylene (DIP) molecules to insert between molecules of a self-assembled monolayer (SAM) during a deposition process intended to grow a thin film of this organic semiconductor molecule onto the surface of self-assembled monolayers. The tendency to insert between SAM molecules is fairly prevalent at normal growth temperatures and conditions, but is most strongly dependent on the density and the nature of the SAM. We posit the existence of an optimal density to favor surface adsorption over insertion for this system. DIP is less likely to insert in fluorinated SAMs, like FOTS (fluorooctatrichlorosilane), than its unfluorinated analog, OTS (octatrichlorosilane). It is also less likely to insert between shorter SAMs (e.g., less insertion in OTS than ODTS (octadecyltrichlorosilane)). Very short length, surface-coating molecules, like HDMS (hexamethyldisilazane), are more likely to scatter energetic incoming DIP molecules with little insertion on first impact (depending on the incident energy of the DIP molecule). Grazing angles of incidence of the depositing molecules generally favor surface adsorption, at least in the limit of low coverage, but are shown to be dependent on the nature of the SAM. The validity of these predictions is confirmed by comparison of the predicted sticking coefficients of DIP at a variety of incident energies on OTS, ODTS, and FOTS SAMs with results obtained experimentally by Desai et al. (2010) [23]. The simulation predictions of the tendency of DIP to insert can be explained, in large part, in terms of binding energies between SAM and DIP molecules. However, we note that entropic and stochastic events play a role in the deposition outcomes. Preliminary studies of multiple deposition events, emulating growth, show an unexpected diffusion of DIP molecules inserted within the

  18. Optimal design of galvanic corrosion protection systems for offshore wind turbine support structures

    DEFF Research Database (Denmark)

    Sarhadi, Ali; Abrahamsen, Asger Bech; Stolpe, Mathias

    2018-01-01

    the optimized anodes on the support structure, and finally evaluating the protective potential on the structure during the lifetime by calling the finite element (FE) software COMSOL. An algorithm based on Sequential Quadratic Programming (SQP) is used for optimizing the number and dimensions of the anodes...... the electrical isolation degradation of the structure coating as well as the mass reduction of the anodes during the CP lifetime. The performance of the proposed optimization process is examined on a mono bucket inspired (with some simplifications) by the Dogger Bank metrological mast in England. The optimized......The current work addresses a mass/cost optimization procedure for galvanic anode cathodic protection (GACP) systems based on both cathodic protection (CP) standards and numerical simulation. An approach is developed for optimizing the number and dimensions of the galvanic anodes, distributing...

  19. Galvanic Replacement Coupled to Seeded Growth as a Route for Shape-Controlled Synthesis of Plasmonic Nanorattles.

    Science.gov (United States)

    Polavarapu, Lakshminarayana; Zanaga, Daniele; Altantzis, Thomas; Rodal-Cedeira, Sergio; Pastoriza-Santos, Isabel; Pérez-Juste, Jorge; Bals, Sara; Liz-Marzán, Luis M

    2016-09-14

    Shape-controlled synthesis of metal nanoparticles (NPs) requires mechanistic understanding toward the development of modern nanoscience and nanotechnology. We demonstrate here an unconventional shape transformation of Au@Ag core-shell NPs (nanorods and nanocubes) into octahedral nanorattles via room-temperature galvanic replacement coupled with seeded growth. The corresponding morphological and chemical transformations were investigated in three dimensions, using state-of-the-art X-ray energy-dispersive spectroscopy (XEDS) tomography. The addition of a reducing agent (ascorbic acid) plays a key role in this unconventional mechanistic path, in which galvanic replacement is found to dominate initially when the shell is made of Ag, while seeded growth suppresses transmetalation when a composition of Au:Ag (∼60:40) is reached in the shell, as revealed by quantitative XEDS tomography. This work not only opens new avenues toward the shape control of hollow NPs beyond the morphology of sacrificial templates, but also expands our understanding of chemical transformations in nanoscale galvanic replacement reactions. The XEDS electron tomography study presented here can be generally applied to investigate a wide range of nanoscale morphological and chemical transformations.

  20. Transmission electron microscopy characterization of the interfacial structure of a galvanized dual-phase steel

    Energy Technology Data Exchange (ETDEWEB)

    Aslam, I., E-mail: ia31@msstate.edu [Center for Advanced Vehicular Systems, Mississippi State University, MS 39759 (United States); Department of Mechanical Engineering, Mississippi State University, MS 39762 (United States); Li, B. [Center for Advanced Vehicular Systems, Mississippi State University, MS 39759 (United States); Department of Chemical and Materials Engineering, University of Nevada, Reno, NV 89557 (United States); Martens, R.L.; Goodwin, J.R. [Central Analytical Facility, the University of Alabama, Tuscaloosa, AL 35487 (United States); Rhee, H.J. [Center for Advanced Vehicular Systems, Mississippi State University, MS 39759 (United States); Department of Mechanical Engineering, Mississippi State University, MS 39762 (United States); Goodwin, F. [International Zinc Association, Durham, NC 27713 (United States)

    2016-10-15

    Site-specific studies were carried out to characterize the interface of a galvanized dual-phase (DP) steel. Focused ion beam (FIB) was used to prepare specimens in the interface region (~ 100 nm thick) between the coating and the substrate. Transmission electron microscopy (TEM), scanning TEM (STEM), and high resolution TEM (HRTEM) were performed to resolve the phases and the structures at the interface between the zinc (Zn) coating and the steel substrate. The STEM and TEM results showed that a continuous manganese oxide (MnO) film with a thickness of ~ 20 nm was present on the surface of the substrate while no silicon (Si) oxides were resolved. Internal oxide particles were observed as well in the sub-surface region. Despite the presence of the continuous oxide film, a well-developed inhibition layer was observed right on top of the oxide film. The inhibition layer has a thickness of ~ 100 nm. Possible mechanisms for the growth of the inhibition layer were discussed. - Highlights: •Site-specific examinations were performed on the Zn/steel interface. •Continuous external MnO oxides (20 nm) were observed at the interface. •No Si oxides were observed at the interface. •Internal oxide particles were distributed in the subsurface. •A continuous inhibition layer grew on top of the external oxides.

  1. Dynamic nanomechanical properties of novel Si-rich intermetallic coatings growth on a medical 316 LVM steel by hot dipping in a hypereutectic Al-25Si alloy.

    Science.gov (United States)

    Frutos, E; González-Carrasco, J L

    2015-06-01

    This aim of this study is to determine the elastoplastic properties of Ni-free Al3FeSi2 intermetallic coatings grown on medical stainless steel under different experimental conditions. Elastoplastic properties are defined by the plasticity index (PI), which correlates the hardness and the Young's modulus. Special emphasis is devoted to correlate the PI with the wear resistance under sliding contact, determined by scratch testing, and fracture toughness, determined by using a novel method based on successive impacts with small loads. With regard to the substrate, the developed coatings are harder and exhibit a lower Young's reduced modulus, irrespective of the experimental conditions. It has been shown that preheating of the samples prior to hot dipping and immersion influences the type and volume fraction of precipitates, which in turn also affect the nanomechanical properties. The higher the preheating temperature is, the greater the Young's reduced modulus is. For a given preheating condition, an increase of the immersion time yields a decrease in hardness. Although apparent friction coefficients of coated specimens are smaller than those obtained on AISI 316 LVM, they increase when using preheating or higher immersion times during processing, which correlates with the PI. The presence of precipitates produces an increase in fracture toughness, with values greater than those presented by samples processed on melted AlSi alloys with lower Si content (12 wt%). Therefore, these intermetallic coatings could be considered "hard but tough", suitable to enhance the wear resistance, especially when using short periods of immersion. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Image mispositioning due to dipping TI media : a physical seismic modelling study

    Energy Technology Data Exchange (ETDEWEB)

    Isaac, J.H.; Lawton, D.C.

    1998-09-01

    Physical modelling experiments were performed to study mispositioning of targets imaged beneath a dipping anisotropic overburden. The significance of the study is that many hydrocarbon resource exploration and development plays in different tectonic settings involve dipping clastic sequences which lie above the reservoir or target zone. In many areas in the Alberta foothills, dipping panels of relatively undeformed Wapiabi shales are found in abundance, overlying deep carbonate reservoirs. These experiments demonstrated the magnitude of the image mispositioning incurred by the use of an inappropriate isotropic processing code when velocity anisotropy was present in the overburden. It was shown that the lateral shift of an imaged target beneath a 1500 m thick, 45 degree dipping anisotropic overburden is significant. Zero-offset data showed a shift in the imaged location of 320 m in the updip direction of the dipping beds, while the shift on stacked time and depth migrated multichannel data was 300 m. 2 refs., 2 figs.

  3. Dip and anisotropy effects on flow using a vertically skewed model grid.

    Science.gov (United States)

    Hoaglund, John R; Pollard, David

    2003-01-01

    Darcy flow equations relating vertical and bedding-parallel flow to vertical and bedding-parallel gradient components are derived for a skewed Cartesian grid in a vertical plane, correcting for structural dip given the principal hydraulic conductivities in bedding-parallel and bedding-orthogonal directions. Incorrect-minus-correct flow error results are presented for ranges of structural dip (0 strike and dip, and a solver that can handle off-diagonal hydraulic conductivity terms.

  4. Effects of deuterium oxide and galvanic vestibular stimulation on visual cortical cell function

    International Nuclear Information System (INIS)

    Reinis, S.; Landolt, J.P.; Weiss, D.S.; Money, K.E.

    1984-01-01

    The spontaneous and evoked unit activities of complex visual cortical cells were recorded from Brodmann's area 18 in immobilized, unanesthetized cats before, during, and after stimulation of the vestibular system. The vestibular system was stimulated by intravenous injection of deuterium oxide (D2O)--a noted nystagmogenic agent--or by direct galvanic stimulation of the labyrinth. Measures of the receptive-field areas, poststimulus time histograms, directional preferences, and the optimal speed of the light bar stimulating the cell were obtained before and after the application of D2O. Directional preferences were determined in a novel manner, using a method derived from a hierarchical clustering technique. Data were collected and analyzed from a) visual cortical cells in cats with intact labyrinths, b) visual cortical cells in cats following bilateral labrinthectomies, and c) nonvisual cortical cells in cats with intact labyrinths. The other cellular characteristics were also altered by the D2O. Galvanic stimulation of the labyrinth resembles, in its effects, the injection of D2O. In labyrinth-intact cats, the time course of area 18 spontaneous activity dramatically increased 30 min or more after D2O was administered. It peaked 2-3 h later and still had not returned to preinjection levels even 7 h after the D2O administration. In bilaterally labyrinthectomized cats, the spontaneous activity of the visual cells did not change following D2O administration. In nonvisual cells from labyrinth-intact cats, the spontaneous activity demonstrated a slight but significant decrease over time after D2O injection. In pilot studies, the cats were injected with D2O. Within 8-10 min afterward, signs of positional nystagmus commenced; and within 30 min, problems in maintaining balance were noted. This continued for 7-8 h before disappearing. In the labyrinthectomized animals, such effects were not observed

  5. Effects of deuterium oxide and galvanic vestibular stimulation on visual cortical cell function

    Energy Technology Data Exchange (ETDEWEB)

    Reinis, S.; Landolt, J.P.; Weiss, D.S.; Money, K.E.

    1984-03-01

    The spontaneous and evoked unit activities of complex visual cortical cells were recorded from Brodmann's area 18 in immobilized, unanesthetized cats before, during, and after stimulation of the vestibular system. The vestibular system was stimulated by intravenous injection of deuterium oxide (D2O)--a noted nystagmogenic agent--or by direct galvanic stimulation of the labyrinth. Measures of the receptive-field areas, poststimulus time histograms, directional preferences, and the optimal speed of the light bar stimulating the cell were obtained before and after the application of D2O. Directional preferences were determined in a novel manner, using a method derived from a hierarchical clustering technique. Data were collected and analyzed from a) visual cortical cells in cats with intact labyrinths, b) visual cortical cells in cats following bilateral labrinthectomies, and c) nonvisual cortical cells in cats with intact labyrinths. The other cellular characteristics were also altered by the D2O. Galvanic stimulation of the labyrinth resembles, in its effects, the injection of D2O. In labyrinth-intact cats, the time course of area 18 spontaneous activity dramatically increased 30 min or more after D2O was administered. It peaked 2-3 h later and still had not returned to preinjection levels even 7 h after the D2O administration. In bilaterally labyrinthectomized cats, the spontaneous activity of the visual cells did not change following D2O administration. In nonvisual cells from labyrinth-intact cats, the spontaneous activity demonstrated a slight but significant decrease over time after D2O injection. In pilot studies, the cats were injected with D2O. Within 8-10 min afterward, signs of positional nystagmus commenced; and within 30 min, problems in maintaining balance were noted. This continued for 7-8 h before disappearing. In the labyrinthectomized animals, such effects were not observed.

  6. Rangeland degradation in semi-arid Swaziland: effects of dip-tanks ...

    African Journals Online (AJOL)

    This study investigated dip-tank use effects on herbaceous vegetation and soil, and relationships between environmental and species variables. Eight dip-tanks, three each in sandy (DPBS) and loamy (DYRL) soils, and two in stony (ROSG) soils were used. Data were collected at 50, 100, 150, 300, 500, 700 and 900 m from ...

  7. Hybrid Coatings Enriched with Tetraethoxysilane for Corrosion Mitigation of Hot-Dip Galvanized Steel in Chloride Contaminated Simulated Concrete Pore Solutions

    Science.gov (United States)

    Figueira, Rita B.; Callone, Emanuela; Silva, Carlos J. R.; Pereira, Elsa V.; Dirè, Sandra

    2017-01-01

    Hybrid sol-gel coatings, named U(X):TEOS, based on ureasilicate matrices (U(X)) enriched with tetraethoxysilane (TEOS), were synthesized. The influence of TEOS addition was studied on both the structure of the hybrid sol-gel films as well as on the electrochemical properties. The effect of TEOS on the structure of the hybrid sol-gel films was investigated by solid state Nuclear Magnetic Resonance. The dielectric properties of the different materials were investigated by electrochemical impedance spectroscopy. The corrosion behavior of the hybrid coatings on HDGS was studied in chloride-contaminated simulated concrete pore solutions (SCPS) by polarization resistance measurements. The roughness of the HDGS coated with hybrids was also characterized by atomic force microscopy. The structural characterization of the hybrid materials proved the effective reaction between Jeffamine® and 3-isocyanate propyltriethoxysilane (ICPTES) and indicated that the addition of TEOS does not seem to affect the organic structure or to increase the degree of condensation of the hybrid materials. Despite the apparent lack of influence on the hybrids architecture, the polarization resistance measurements confirmed that TEOS addition improves the corrosion resistance of the hybrid coatings (U(X):TEOS) in chloride-contaminated SCPS when compared to samples prepared without any TEOS (U(X)). This behavior could be related to the decrease in roughness of the hybrid coatings (due TEOS addition) and to the different metal coating interaction resulting from the increase of the inorganic component in the hybrid matrix. PMID:28772667

  8. Continuous production of fenofibrate solid lipid nanoparticles by hot-melt extrusion technology: a systematic study based on a quality by design approach.

    Science.gov (United States)

    Patil, Hemlata; Feng, Xin; Ye, Xingyou; Majumdar, Soumyajit; Repka, Michael A

    2015-01-01

    This contribution describes a continuous process for the production of solid lipid nanoparticles (SLN) as drug-carrier systems via hot-melt extrusion (HME). Presently, HME technology has not been used for the manufacturing of SLN. Generally, SLN are prepared as a batch process, which is time consuming and may result in variability of end-product quality attributes. In this study, using Quality by Design (QbD) principles, we were able to achieve continuous production of SLN by combining two processes: HME technology for melt-emulsification and high-pressure homogenization (HPH) for size reduction. Fenofibrate (FBT), a poorly water-soluble model drug, was incorporated into SLN using HME-HPH methods. The developed novel platform demonstrated better process control and size reduction compared to the conventional process of hot homogenization (batch process). Varying the process parameters enabled the production of SLN below 200 nm. The dissolution profile of the FBT SLN prepared by the novel HME-HPH method was faster than that of the crude FBT and a micronized marketed FBT formulation. At the end of a 5-h in vitro dissolution study, a SLN formulation released 92-93% of drug, whereas drug release was approximately 65 and 45% for the marketed micronized formulation and crude drug, respectively. Also, pharmacokinetic study results demonstrated a statistical increase in Cmax, Tmax, and AUC0-24 h in the rate of drug absorption from SLN formulations as compared to the crude drug and marketed micronized formulation. In summary, the present study demonstrated the potential use of hot-melt extrusion technology for continuous and large-scale production of SLN.

  9. Experimental Modeling of Dynamic Shallow Dip-Slip Faulting

    Science.gov (United States)

    Uenishi, K.

    2010-12-01

    In our earlier study (AGU 2005, SSJ 2005, JPGU 2006), using a finite difference technique, we have conducted some numerical simulations related to the source dynamics of shallow dip-slip earthquakes, and suggested the possibility of the existence of corner waves, i.e., shear waves that carry concentrated kinematic energy and generate extremely strong particle motions on the hanging wall of a nonvertical fault. In the numerical models, a dip-slip fault is located in a two-dimensional, monolithic linear elastic half space, and the fault plane dips either vertically or 45 degrees. We have investigated the seismic wave field radiated by crack-like rupture of this straight fault. If the fault rupture, initiated at depth, arrests just below or reaches the free surface, four Rayleigh-type pulses are generated: two propagating along the free surface into the opposite directions to the far field, the other two moving back along the ruptured fault surface (interface) downwards into depth. These downward interface pulses may largely control the stopping phase of the dynamic rupture, and in the case the fault plane is inclined, on the hanging wall the interface pulse and the outward-moving Rayleigh surface pulse interact with each other and the corner wave is induced. On the footwall, the ground motion is dominated simply by the weaker Rayleigh pulse propagating along the free surface because of much smaller interaction between this Rayleigh and the interface pulse. The generation of the downward interface pulses and corner wave may play a crucial role in understanding the effects of the geometrical asymmetry on the strong motion induced by shallow dip-slip faulting, but it has not been well recognized so far, partly because those waves are not expected for a fault that is located and ruptures only at depth. However, the seismological recordings of the 1999 Chi-Chi, Taiwan, the 2004 Niigata-ken Chuetsu, Japan, earthquakes as well as a more recent one in Iwate-Miyagi Inland

  10. Galvanically Decoupled Current Source Modules for Multi-Channel Bioimpedance Measurement Systems

    Directory of Open Access Journals (Sweden)

    Roman Kusche

    2017-10-01

    Full Text Available Bioimpedance measurements have become a useful technique in the past several years in biomedical engineering. Especially, multi-channel measurements facilitate new imaging and patient monitoring techniques. While most instrumentation research has focused on signal acquisition and signal processing, this work proposes the design of an excitation current source module that can be easily implemented in existing or upcoming bioimpedance measurement systems. It is galvanically isolated to enable simultaneous multi-channel bioimpedance measurements with a very low channel-coupling. The system is based on a microcontroller in combination with a voltage-controlled current source circuit. It generates selectable sinusoidal excitation signals between 0.12 and 1.5 mA in a frequency range from 12 to 250 kHz, whereas the voltage compliance range is ±3.2 V. The coupling factor between two current sources, experimentally galvanically connected with each other, is measured to be less than −48 dB over the entire intended frequency range. Finally, suggestions for developments in the future are made.

  11. Influence of surface modified nanoilmenite/amorphous silica composite particles on the thermal stability of cold galvanizing coating

    Directory of Open Access Journals (Sweden)

    A.M. Al-Sabagh

    2018-03-01

    Full Text Available The present approach investigates the use of novel nanoilmenite/amorphous silica composite (NI/AS particles fabricated from ilmenite nanoparticles (FeTiO3 NPs and synthesized amorphous silica grains to improve thermal stability of the cold galvanizing coating. Transmission electron microscopic (TEM images demonstrated that both nanoilmenite and nanocomposite particles were of flaky-like nature and the average diameter of the particles is 20 nm. The lamellar shape of the nanocomposite and spherical nature of Zn-dust particles were illustrated by scanning electron microscopy (SEM micrographs. Different alkyd-based cold galvanizing coating formulations were modified using uniformly dispersing various amounts of the processed nanocomposite particles as a modifier to form some engineering nanocomposite coatings. Thermal stability of the nanocomposite and Zn-dust particles was determined by thermo-gravimetric analysis (TGA. From the obtained results it could be observed that the weight loss (% as a feature of the thermal stability in case of the nanocomposite particles was 2.9 compared to 85.9 for Zn-dust powder grains. Derivative thermo-gravimetric (DTG measurements were done under nitrogen atmosphere for the cured cold galvanizing coating samples heated from room temperature to 1000 °C. The obtained results revealed that the maximum decomposition temperature point in the third degradation step for 6% nanocomposite surface modified cured sample (CG-F was detected at 693 °C and was less value for unmodified conventional cold galvanizing coating (CG-A at 612 °C. The increase in thermal stability with increasing the concentration of nanocomposite particles could be mainly attributed to the interface surface interaction between the nanocomposite particles and alkyd resin matrix in which enhancing the inorganic-organic network stiffness by causing a reduction in the total free spaces and enhancement in the cross-linking density of the cured film

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

    Science.gov (United States)

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

    2017-06-20

    Lead exposure via drinking water remains a significant public health risk; this study explored the potential effects of upstream iron corrosion on lead mobility in water distribution systems. Specifically, galvanic corrosion of lead by iron (oxyhydr)oxides was investigated. Coupling an iron mineral cathode with metallic lead in a galvanic cell increased lead release by 531 μg L -1 on average-a 9-fold increase over uniform corrosion in the absence of iron. Cathodes were composed of spark plasma sintered Fe 3 O 4 or α-Fe 2 O 3 or field-extracted Fe 3 O 4 and α-FeOOH. Orthophosphate immobilized oxidized lead as insoluble hydroxypyromorphite, while humic acid enhanced lead mobility. Addition of a humic isolate increased lead release due to uniform corrosion by 81 μg L -1 and-upon coupling lead to a mineral cathode-release due to galvanic corrosion by 990 μg L -1 . Elevated lead in the presence of humic acid appeared to be driven by complexation, with 208 Pb and UV 254 size-exclusion chromatograms exhibiting strong correlation under these conditions (R 2 average = 0.87). A significant iron corrosion effect was consistent with field data: lead levels after lead service line replacement were greater by factors of 2.3-4.7 at sites supplied by unlined cast iron distribution mains compared with the alternative, lined ductile iron.

  13. Dip Phenomenon in High-Curved Turbulent Flows and Application of Entropy Theory

    Directory of Open Access Journals (Sweden)

    Donatella Termini

    2018-03-01

    Full Text Available The estimation of velocity profile in turbulent open channels is a difficult task due to the significant effects of the secondary flow. The present paper investigates the mechanism of the velocity-dip phenomenon, whereby the location of the maximum velocity appears to be below the free surface. Previous studies conducted in straight channels relate the mechanism of the velocity-dip phenomenon to secondary flow induced by anisotropy of turbulence. This work focuses on high-curved channels where the secondary motion, which is also induced by the channel’s curvature, evolves along the bend. The width-to-depth ratio, B/h, is one of the most important parameters that are affecting the secondary motion entity. In particular, the present study aims to investigate the evolution of the velocity-dip along the bend for two values of the width-to-depth ratio and the applicability of the entropic model for the dip-phenomenon estimation. The results show that the velocity-dip is more accentuated for low values of the width-to-depth ratio, where the secondary motion plays a fundamental role in the distribution of the downstream flow velocity, although the velocity-dip is also present when the aspect ratio is higher than 10. Furthermore, the velocity profiles that were estimated by applying the entropic model are in good agreement with the measured ones, especially for B/h < 10.

  14. Importance of temperature, pH, and boric acid concentration on rates of hydrogen production from galvanized steel corrosion

    International Nuclear Information System (INIS)

    Loyola, V.M.

    1982-01-01

    One of the known sources of hydrogen gas within a nuclear plant containment building during a LOCA is the high temperature corrosion of galvanized steel yielding hydrogen gas. The importance of this source of hydrogen will vary depending on the severity of the accident. In an accident which resulted in core degradation, for example, the major source of hydrogen would probably be the metal-water reaction of the zircaloy cladding, and the corrosion of galvanized steel would then become a relatively minor source of hydrogen. However, in an accident in which core degradation is avoided or limited to minor damage, the corrosion of galvanized steel, and presumably of other materials as well, would then become a major contributor to the buildup of hydrogen within containment. The purpose of this paper is to present the overall effects of temperature, pH, and boric acid concentration on the rate of hydrogen generation over a broad range of each parameter

  15. Hot ductility of medium carbon steel with vanadium

    International Nuclear Information System (INIS)

    Lee, Chang-Hoon; Park, Jun-Young; Chung, JunHo; Park, Dae-Bum; Jang, Jin-Young; Huh, Sungyul; Ju Kim, Sung; Kang, Jun-Yun; Moon, Joonoh; Lee, Tae-Ho

    2016-01-01

    Hot ductility of medium carbon steel containing 0.52 wt% of carbon and 0.11 wt% of vanadium was investigated using a hot tensile test performed up to fracture. The hot ductility was evaluated by measuring the reduction of area of the fractured specimens, which were strained at a variety of test temperatures in a range of 600–1100 °C at a strain rate of 2×10"−"3/s. The hot ductility was excellent in a temperature range of 950–1100 °C, followed by a decrease of the hot ductility below 950 °C. The hot ductility continued to drop as the temperature was lowered to 600 °C. The loss of hot ductility in a temperature range of 800–950 °C, which is above the Ae_3 temperature, was due to V(C,N) precipitation at austenite grain boundaries. The further decline of hot ductility between 700 °C and 750 °C resulted from the transformation of ferrite films decorating austenite grain boundaries. The hot ductility continued to decrease at 650 °C or less, owing to ferrite films and the pearlite matrix, which is harder than ferrite. The pearlite was transformed from austenite due to relatively high carbon content.

  16. Dipping Strawberry Plants in Fungicides before Planting to Control Anthracnose

    Directory of Open Access Journals (Sweden)

    Myeong Hyeon Nam

    2014-03-01

    Full Text Available Anthracnose crown rot (ACR, caused by Colletotrichum fructicola, is a serious disease of strawberry in Korea. The primary inoculums of ACR were symptomless strawberry plants, plant debris, and other host plants. To effectively control anthracnose in symptomless transplanted strawberries, it is necessary to use diseasefree plants, detect the disease early, and apply a fungicide. Therefore, in 2010 and 2011, we evaluated the efficacy of pre-plant fungicide dips by using strawberry transplants infected by C. fructicola for the control of anthracnose. Dipping plants in prochloraz-Mn for 10 min before planting was most effective for controlling anthracnose in symptomless strawberry plants and resulted in more than 76% control efficacy. Azoxystrobin showed a control efficacy of over 40%, but plants treated with pyraclostrobin, mancozeb and iminoctadine tris showed high disease severity. The control efficacy of the dip treatment with prochloraz-Mn did not differ with temperature and time. Treatment with prochloraz-Mn for more than an hour caused growth suppression in strawberry plants. Therefore, the development of anthracnose can be effectively reduced by dipping strawberry plants for 10 min in prochloraz-Mn before planting.

  17. Assessment of voltage dips based on field measurements in MV networks

    NARCIS (Netherlands)

    Weldemariam, L.E.; Papathanasiou, F.; Cuk, V.; Cobben, J.F.G.; Kling, W.L.

    Voltage dip is considered as the PQ problem related to the highest financial losses for the customers. It occurs unpredictably mainly due to short-circuit faults in the networks. Network operators and customers want to know more about the occurrence and the potential impact of voltage dips. PQ

  18. EFFECT OF CHEMICAL MODIFICATION AND HOT-PRESS DRYING ON POPLAR WOOD

    Directory of Open Access Journals (Sweden)

    Guo-Feng Wu

    2010-11-01

    Full Text Available Urea-formaldehyde prepolymer and hot-press drying were used to improve the properties of poplar wood. The wood was impregnated with the prepolymer using a pulse-dipping machine. The impregnated timbers were compressed and dried by a multilayer hot-press drying kiln. The drying rate was more rapid during the chemical modification and hot-press drying than conventional kiln-drying. In addition, the properties of timber were also enhanced obviously. When the compression rate was 28.6%, the basic density, oven dry density and air-dried density of modified wood improved 22%, 71%, and 70%, respectively. The bending strength and compressive strength parallel to grain increased 60% and 40%. The water uptake of treated wood was significantly decreased compared with the untreated wood. The FTIR analysis successfully showed that the intensity of hydroxyl and carbonyl absorption peaks decreased significantly, which was attributed to a reaction of the NHCH2OH of urea-formaldehyde prepolymer with the wood carboxyl (C=O and hydroxyl (-OH groups. The XRD results indicated that the degree of crystallinity increased from 35.09% to 36.91%. The morphologic models of chemical within wood were discovered by SEM.

  19. The potential of postharvest silicon dips to regulate phenolics in ...

    African Journals Online (AJOL)

    This study investigated the ability of silicon dips to enhance the phenolic content in order to reduce the incidence of chilling injury in lemon fruit. Fruits were obtained from two farms and dipped in 0, 50, 150 and 250 mg L-1 solutions of K2SiO3 for 30 min and afterward, fruit were air dried and waxed. Thereafter, fruits were ...

  20. EXOSAT observations of V471 Tauri - a 9.25 minute white dwarf pulsation and orbital phase dependent X-ray dips

    International Nuclear Information System (INIS)

    Jensen, K.A.; Swank, J.H.; Petre, P.; Guinan, E.F.; Sion, E.M.; Navy, E. O. Hulburt Center for Space Research, Washington, DC; Villanova Univ., PA)

    1986-01-01

    New results obtained from a 28 hr continuous observation of V471 Tauri with the EXOSAT satellite are reported. The detection of soft X-ray fluxes from both the white dwarf and the K dwarf, the discovery of a 9.25 minute pulsation from the white dwarf, and the discovery of orbital phase-related soft X-ray dips are discussed. The dips may be correlated with the triangular Lagrangian points of the binary orbit. The X-ray flux from the white dwarf is consistent with thermal models for a white dwarf photosphere with T(eff) of about 35,000 K, log g = 8.0-8.5, and log N(H) = 18.65 + or - 0.2. 25 references

  1. Galvanic corrosion of Al 1S and Al 57S in demineralised water

    International Nuclear Information System (INIS)

    Chouthai, S.S.; Shibad, P.R.; Gadiyar, H.S.

    1987-01-01

    Experiments were conducted on A1-1S and A1-57S to investigate the effect of galvanic coupling between the two on the corrosion rates, on exposure to demineralised water at room temperature. The results indicated that such galvanic effects were not observed. Specimens pretreated in 2 per cent sodium oxalate and also in 3 per cent oxalic acid showed lower corrosion rates as compared to specimens without any treatment. AES studies carried out on A1-1S and A1-57S both untreated and treated in 2 per cent sodium oxalate and in 3 per cent oxalic acid solution revealed bulk of the passive film to be an oxide of aluminium with differences in thicknesses for the two materials. Thinner films were seen on A1-57S as compared to A1-1S. (author). 5 tables, 7 figures

  2. Dissimilar joining of galvanized high-strength steel to aluminum alloy in a zero-gap lap joint configuration by two-pass laser welding

    International Nuclear Information System (INIS)

    Ma, Junjie; Harooni, Masoud; Carlson, Blair; Kovacevic, Radovan

    2014-01-01

    Highlights: • Defect-free two-pass laser partially penetrated lap joint of galvanized steel to aluminum was achieved. • The thickness of the Al-rich intermetallic compounds could be controlled by optimal parameters. • The dynamic behavior of the molten pool and keyhole were monitored by a high speed charge-coupled device camera. • The presence of zinc in the intermetallic compounds could improve the strength of the lap joints. - Abstract: A welding procedure based on using two-pass laser scans is introduced for dissimilar joining of overlapped galvanized high-strength dual-phase (DP) steel DP590 to aluminum alloy (AA) 6061 sheets. The first pass is based on a defocused laser spot that scans across the top of the two overlapped sheets and heats the zinc coating at the faying surface to be melted and partially vaporized, while the second pass is executed with a focused laser spot in order to perform the welding. Completely defect-free galvanized steel to aluminum lap joints were obtained by using this two-pass laser welding procedure. An on-line machine vision system was applied to monitor the keyhole dynamics during the laser welding process. An energy-dispersive X-ray spectroscopy (EDS) was carried out to determine the atomic percent of zinc, aluminum, and iron in the galvanized steel to aluminum lap joints. Mechanical testing and micro-hardness test were conducted to evaluate the mechanical properties of the galvanized steel to aluminum lap joints. The experimental results showed that the lap joint of galvanized steel to aluminum obtained by the two-pass laser welding approach had a higher failure value than those joints obtained when the zinc at the faying surface was mechanically removed under the same welding speed and laser power

  3. Trapping dynamics of diindenoperylene (DIP) in self-assembled monolayers using molecular simulation

    KAUST Repository

    Kaushik, Ananth P.; Clancy, Paulette

    2011-01-01

    (hexamethyldisilazane), are more likely to scatter energetic incoming DIP molecules with little insertion on first impact (depending on the incident energy of the DIP molecule). Grazing angles of incidence of the depositing molecules generally favor surface adsorption

  4. DIP1 modulates stem cell homeostasis in Drosophila through regulation of sisR-1.

    Science.gov (United States)

    Wong, Jing Ting; Akhbar, Farzanah; Ng, Amanda Yunn Ee; Tay, Mandy Li-Ian; Loi, Gladys Jing En; Pek, Jun Wei

    2017-10-02

    Stable intronic sequence RNAs (sisRNAs) are by-products of splicing and regulate gene expression. How sisRNAs are regulated is unclear. Here we report that a double-stranded RNA binding protein, Disco-interacting protein 1 (DIP1) regulates sisRNAs in Drosophila. DIP1 negatively regulates the abundance of sisR-1 and INE-1 sisRNAs. Fine-tuning of sisR-1 by DIP1 is important to maintain female germline stem cell homeostasis by modulating germline stem cell differentiation and niche adhesion. Drosophila DIP1 localizes to a nuclear body (satellite body) and associates with the fourth chromosome, which contains a very high density of INE-1 transposable element sequences that are processed into sisRNAs. DIP1 presumably acts outside the satellite bodies to regulate sisR-1, which is not on the fourth chromosome. Thus, our study identifies DIP1 as a sisRNA regulatory protein that controls germline stem cell self-renewal in Drosophila.Stable intronic sequence RNAs (sisRNAs) are by-products of splicing from introns with roles in embryonic development in Drosophila. Here, the authors show that the RNA binding protein DIP1 regulates sisRNAs in Drosophila, which is necessary for germline stem cell homeostasis.

  5. Current trend in latex dipped products manufacturing

    International Nuclear Information System (INIS)

    Wong, W.S.C.

    1996-01-01

    The paper present the activities in dipped products manufacturing in Malaysia; the activities carried out by MARGMA - Malaysian Rubber Glove manufacturer; other issues discussed such as labour, pricing environmental issue, product certification in this activity

  6. A new method for the compensation of ohmic drop in galvanic cells

    NARCIS (Netherlands)

    Kooijman, D.J.; Sluyters, J.H.

    Generally the ohmic potential drop in a galvanic cell that occurs if a rectangular pulse is led through the cell, is compensated by means of a well-known bridge circuit. A better method making use of a phase reverter is described and its features are discussed. Exchange current densities up to 1200

  7. Structural analysis of CdS thin films obtained by multiple dips of oscillating chemical bath

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez Lazos, C.D. [Seccion de Electronica del Estado Solido, Centro de Investigacion y de Estudios Avanzados, Av. Instituto Politecnico Nacional 2508, Col. San Pedro Zacatenco, 07360 Mexico, D.F. (Mexico); Rosendo, E., E-mail: erosendo@siu.buap.m [Centro de Investigacion en Dispositivos Semiconductores, Universidad Autonoma de Puebla, 14 Sur y San Claudio, Col. San Manuel, C.P. 72570, Puebla (Mexico); Ortega, M. [Seccion de Electronica del Estado Solido, Centro de Investigacion y de Estudios Avanzados, Av. Instituto Politecnico Nacional 2508, Col. San Pedro Zacatenco, 07360 Mexico, D.F. (Mexico); Oliva, A.I. [Departamento de Fisica Aplicada, Centro de Investigacion y de Estudios Avanzados, Unidad Merida, A.P. 73 Cordemex, 97310 Merida, Yucatan (Mexico); Tapia, O.; Diaz, T.; Juarez, H.; Garcia, G. [Centro de Investigacion en Dispositivos Semiconductores, Universidad Autonoma de Puebla, 14 Sur y San Claudio, Col. San Manuel, C.P. 72570, Puebla (Mexico); Rubin, M. [Facultad de Ciencias de la Computacion, 14 Sur y San Claudio, Col. San Manuel, C.P. 72570, Puebla (Mexico)

    2009-11-25

    Highly oriented CdS thin films with thicknesses greater than 1 mum were deposited by multiple dips, using oscillating chemical bath deposition (OCBD) at the bath temperature of 75 deg. C, and deposition time ranging from 15 to 75 min for a single dip. Samples with different thickness were prepared by repeating the deposition process for two and three times. The films deposited by a single dip have the alpha-greenockite structure showing the (0 0 2) as preferred orientation, as indicated by the X-ray diffraction measurements. This notable characteristic is preserved in the samples obtained from two or three dips. The crystallite size for the samples deposited by a single dip depends on the deposition time, because it varied from 23 to 37 nm as the deposition time increased. Nevertheless for samples deposited by two and three dips, the grain size shows no noticeable change, being about 22 nm.

  8. Particle and power balances of hot-filament discharge plasmas in a multi-dipole device in the presence of a positively biased electrode

    International Nuclear Information System (INIS)

    Cho, M.H.; Hershkowitz, N.; Intrator, T.

    1989-01-01

    The plasma potential is typically assumed to float above an anode potential by a few times of an electron temperature (T /e). The difference between the plasma potential and the anode potential can be estimated by considering the particle production and loss. However, it has been reported experimentally that the plasma potential of a steady state plasma can be more negative than the anode potential with a potential dip (-- T /e) in front of the anode. This paper describes particle and power balances to estimate the bulk plasma potential of a hot-filament discharge plasma produced in a multi-dipole plasma device. The bulk plasma potential dependence on positive DC bias applied to an anode is analyzed, and the predicted characteristics of the plasma potential dependence are compared to the experiment. A steady state potential dip in front of an anode is experimentally observed using emissive probes with the zero emission inflection point method, and the conditions for the potential dip formation are derived

  9. Growth and galvanic replacement of silver nanocubes in organic media

    Science.gov (United States)

    Polavarapu, Lakshminarayana; Liz-Marzán, Luis M.

    2013-05-01

    Although metal nanoparticles with various shapes can be prepared in polar organic solvents, little has been advanced toward the shape-controlled synthesis in non-polar solvents. We report a simple method for the synthesis of nearly monodisperse single crystalline silver nanocubes in a non-polar solvent (1,2-dichlorobenzene) by using oleylamine as both a reducing and capping agent. Mechanistic studies based on the time evolution of Ag nanoparticles revealed that multiply twinned nanocrystals form at the beginning of the reaction, which are gradually transformed into single crystalline Ag nanocubes by oxidative etching. Control experiments showed that the solvent plays an important role in the formation of such single crystalline Ag nanocubes. The effects of reaction temperature, oleylamine concentration, solvent, and the nature of the silver ion precursor on the morphology and monodispersity of the nanoparticles were systematically investigated. Additionally, the galvanic replacement reaction with HAuCl4 in an organic medium was implemented to prepare hydrophobic hollow Au-Ag nanocages with tunable localized surface plasmon resonances.Although metal nanoparticles with various shapes can be prepared in polar organic solvents, little has been advanced toward the shape-controlled synthesis in non-polar solvents. We report a simple method for the synthesis of nearly monodisperse single crystalline silver nanocubes in a non-polar solvent (1,2-dichlorobenzene) by using oleylamine as both a reducing and capping agent. Mechanistic studies based on the time evolution of Ag nanoparticles revealed that multiply twinned nanocrystals form at the beginning of the reaction, which are gradually transformed into single crystalline Ag nanocubes by oxidative etching. Control experiments showed that the solvent plays an important role in the formation of such single crystalline Ag nanocubes. The effects of reaction temperature, oleylamine concentration, solvent, and the nature of the

  10. Synthesis of active absorber layer by dip-coating method for perovskite solar cell

    Science.gov (United States)

    Singh, Rahul; Noor, I. M.; Singh, Pramod K.; Bhattacharya, B.; Arof, A. K.

    2018-04-01

    In this paper, we develop the hybrid perovskite-based n-i-p solar cell using a simple, fast and low-cost dip-coating method. Hot solution and the pre-annealed substrate are used for coating the perovskite thin film by this method this is further used for studying its structural and electrical properties. UV-vis spectroscopy is carried out for calculating the band gap of the hybrid perovskite layer which is ∼1.6 eV. X-ray spectroscopy confirms that the formation of hybrid perovskite layer. The profilometer is used to study the surface roughness and also for measuring the thickness of the perovskite layer with varying substrate temperature. The optimized sample was further used for cross-sectional SEM image to verify the thickness measured from the profiler. The electrical parameter of JV characteristic with varying temperature is tabulated in the table. Whereas, the perovskite sensitized solar cell exhibits highest short circuit current density, Jsc of 11 mA cm-2, open circuit voltage, Voc of 0.87 V, fill factor of 0.55 and efficiency, η of >5%.

  11. Monitoring of Dips in the MV Network for Regulation- A Case Study

    NARCIS (Netherlands)

    Weldemariam, L.E.; Cuk, V.; Cobben, J.F.G.; Kling, W.L.

    2014-01-01

    Abstract— Voltage dips constitute to a noticeable part of power quality (PQ) problems but causing major financial losses to industrial and commercial customers. This work involves comparative studies to choose the most appropriate location of monitoring dips for regulation. In this paper, a Dutch MV

  12. Development of flow-through and dip-stick immunoassays for screening of sulfonamide residues.

    Science.gov (United States)

    Zhang, Hongyan; Zhang, Yan; Wang, Shuo

    2008-08-20

    Two formats of membrane-based competitive enzyme immunoassays (flow-through and dip-stick) have been developed for the screening of sulfonamide residues in pig muscle and milk. Membrane was coated with anti-sulfonamide antibody and a sulfonamide hapten D2-horseradish peroxidase (HRP) conjugant was used as the labeled antigen for competitive assay of sulfonamides. Visual detection limits of the flow-through or dip-stick assay were 1-5 microg L(-1) or 1-10 microg L(-1) in buffer for seven sulfonamides, respectively. Assay validation was performed using samples spiked with single sulfonamide, spiked samples were tested using the developed strip assays and results were compared with those obtained by a validated high-performance liquid chromatograph (HPLC) method. Results showed that the two strip assays were correlated well with HPLC, respectively. With assay times of 5 min (flow-through) and 15 min (dip-stick), these rapid tests could offer simple, rapid and cost-effective on-site screening tools to detect sulfonamides in pig muscle (flow-through or dip-stick) or milk (only dip-stick).

  13. Thermal analysis of continuous and patterned multilayer films in the presence of a nanoscale hot spot

    Science.gov (United States)

    Juang, Jia-Yang; Zheng, Jinglin

    2016-10-01

    Thermal responses of multilayer films play essential roles in state-of-the-art electronic systems, such as photo/micro-electronic devices, data storage systems, and silicon-on-insulator transistors. In this paper, we focus on the thermal aspects of multilayer films in the presence of a nanoscale hot spot induced by near field laser heating. The problem is set up in the scenario of heat assisted magnetic recording (HAMR), the next-generation technology to overcome the data storage density limit imposed by superparamagnetism. We characterized thermal responses of both continuous and patterned multilayer media films using transient thermal modeling. We observed that material configurations, in particular, the thermal barriers at the material layer interfaces crucially impact the temperature field hence play a key role in determining the hot spot geometry, transient response and power consumption. With a representative generic media model, we further explored the possibility of optimizing thermal performances by designing layers of heat sink and thermal barrier. The modeling approach demonstrates an effective way to characterize thermal behaviors of micro and nano-scale electronic devices with multilayer thin film structures. The insights into the thermal transport scheme will be critical for design and operations of such electronic devices.

  14. Reducción de problemas de adherencia en procesos de galvanizado mediante técnicas de minería de datos

    Directory of Open Access Journals (Sweden)

    Martínez-de-Pisón, F. J.

    2007-10-01

    Full Text Available This paper presents an example of the application of data mining techniques to obtain hidden knowledge from the historical data of a hot dip galvanizing process and to establish rules to improve quality in the final product and to reduce errors in the process. For this purpose, the tuning records of a hot dip galvanizing line where coils with adherence problems in the zinc coating had been identified were used as a starting point. From the database of the process, the classical data mining approach was applied to obtain and analyze a number of decision trees that classified two types of coils, i.e. those with the right adherence and those with irregular adherence. The variables and values that might have influenced the quality of the coating were extracted from these trees. Several rules that may be applied to reduce the number of faulty coils with adherence problems were also established.

    En este trabajo, se muestra un ejemplo de aplicación de técnicas de minería de datos para la obtención de conocimiento oculto a partir de los históricos de un proceso de galvanizado. El objetivo consistió en encontrar reglas que pudieran servir para mejorar la calidad del producto final y reducir los fallos del proceso. Para ello, se partió de los históricos correspondientes a la etapa de ajuste de una línea de galvanizado donde surgieron bobinas con problemas en la adherencia del recubrimiento de zinc aplicado. A partir de la base de datos de dicho proceso, se aplicó la metodología clásica de minería de datos para generar y analizar diversos árboles de decisión que clasificaban dos tipos de clases: las bobinas con adherencia correcta y las que presentaban adherencia irregular. De estos árboles se extrajeron las variables y sus valores, que más podían influir en la calidad del recubrimiento. Además, se establecieron reglas que podían ser aplicadas para reducir el número de bobinas con fallos de adherencia.

  15. Zinc corrosion after loss-of-coolant accidents in pressurized water reactors – Thermo- and fluid-dynamic effects

    Energy Technology Data Exchange (ETDEWEB)

    Seeliger, André, E-mail: a.seeliger@hszg.de [Hochschule Zittau/Görlitz, Institute of Process Technology, Process Automation and Measuring Technology, Theodor-Körner-Allee 16, D-02763 Zittau (Germany); Alt, Sören; Kästner, Wolfgang; Renger, Stefan [Hochschule Zittau/Görlitz, Institute of Process Technology, Process Automation and Measuring Technology, Theodor-Körner-Allee 16, D-02763 Zittau (Germany); Kryk, Holger; Harm, Ulrich [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Fluid Dynamics, P.O. Box 510119, D-01314 Dresden (Germany)

    2016-08-15

    Highlights: • Borated coolant supports corrosion at zinc-coated installations in PWR after LOCA. • Dissolved zinc is injected into core by ECCS during sump recirculation phase. • Corrosion products can reach and settle at further downstream components. • Corrosion products can cause head losses at spacers and influence decay heat removal. • Preventive procedures were tested at semi-technical scale facilities. - Abstract: Within the framework of the German reactor safety research, generic experimental investigations were carried out aiming at thermal-hydraulic consequences of physicochemical mechanisms, caused by dissolution of zinc in boric acid during corrosion processes at hot-dip galvanized surfaces of containment internals at lower coolant temperatures and the subsequent precipitation of solid zinc borates in PWR core regions of higher temperature. This constellation can occur during sump recirculation operation of ECCS after LOCA. Hot-dip galvanized compounds, which are installed inside a PWR containment, may act as zinc sources. Getting in contact with boric acid coolant, zinc at their surfaces is released into coolant in form of ions due to corrosion processes. As a long-term behavior resp. over a time period of several days, metal layers of zinc and zinc alloys can dissolve extensively. First fundamental studies at laboratory scale were done at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). Their experimental results were picked up for the definition of boundary conditions for experiments at semi-technical scale at the Hochschule Zittau/Görlitz (HSZG). Electrical heating rods with zircaloy cladding tubes have been used as fuel rod simulators. As near-plant core components, a 3 × 3 configuration of heating rods (HRC) and a shortened, partially heatable PWR fuel assembly dummy were applied into cooling circuits. The HRC module includes segments of spacers for a suitable representation of a heating channel geometry. Formations of different solid

  16. Effect of the Type of Surface Treatment and Cement on the Chloride Induced Corrosion of Galvanized Reinforcements

    Science.gov (United States)

    Tittarelli, Francesca; Mobili, Alessandra; Vicerè, Anna Maria; Roventi, Gabriella; Bellezze, Tiziano

    2017-10-01

    The effect of a new passivation treatment, obtained by immersion of the galvanized reinforcements in a trivalent chromium salts based solution, on the chlorides induced corrosion has been investigated. To investigate also the effect of cement alkalinity on corrosion behaviour of reinforcements, concretes manufactured with three different European cements were compared. The obtained results show that the alternative treatment based on hexavalent chromium-free baths forms effective protection layers on the galvanized rebar surfaces. The higher corrosion rates of zinc coating in concrete manufactured with Portland cement compared to those recorded for bars in concrete manufactured with pozzolanic cement depends strongly on the higher chloride content at the steel concrete interface.

  17. Corrosion Degradation of Coated Aluminum Alloy Systems through Galvanic Interactions

    Science.gov (United States)

    2017-07-19

    REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...19b. TELEPHONE NUMBER (Include area code) Corrosion  Degradation  of  Coated  Aluminum  Alloy  Systems  through  Galvanic...their  low  density  and  relatively  high  strength.   While  exhibiting  significant  general   corrosion  resistance,  these

  18. Efficiency dip observed with InGaN-based multiple quantum well solar cells

    KAUST Repository

    Lai, Kunyu; Lin, G. J.; Wu, Yuhrenn; Tsai, Menglun; He, Jr-Hau

    2014-01-01

    The dip of external quantum efficiency (EQE) is observed on In0.15Ga0.85N/GaN multiple quantum well (MQW) solar cells upon the increase of incident optical power density. With indium composition increased to 25%, the EQE dip becomes much less noticeable. The composition dependence of EQE dip is ascribed to the competition between radiative recombination and photocurrent generation in the active region, which are dictated by quantum-confined Stark effect (QCSE) and composition fluctuation in the MQWs.

  19. Dip-Coating Process Engineering and Performance Optimization for Three-State Electrochromic Devices

    Science.gov (United States)

    Wu, Lu; Yang, Dejiang; Fei, Lixun; Huang, Yue; Wu, Fang; Sun, Yiling; Shi, Jiayuan; Xiang, Yong

    2017-06-01

    Titanium dioxide (TiO2) nanoparticles were modified onto fluorine-doped tin oxide (FTO) via dip-coating technique with different nanoparticle sizes, lifting speeds, precursor concentrations, and dipping numbers. Electrodeposition-based electrochromic device with reversible three-state optical transformation (transparent, mirror, and black) was fabricated subsequently by sandwiching a suitable amount of gel electrolyte between modified FTO electrode and flat FTO electrode. Correlation between dip-coating process engineering, morphological features of TiO2 thin films, i.e., thickness and roughness, as well as performance of electrochromic devices, i.e., optical contrast, switching time, and cycling stability, were investigated. The modified device exhibits high optical contrast of 57%, the short coloration/bleaching switching time of 6 and 20 s, and excellent cycling stability after 1500 cycles of only 27% decrement rate by adjusting dip-coating processes engineering. The results in this study will provide valuable guidance for rational design of the electrochromic device with satisfactory performance.

  20. Electrochemical Degradation of Phenol and Resorcinol Molecules through the Dissolution of Sacrificial Anodes of Macro-Corrosion Galvanic Cells

    Directory of Open Access Journals (Sweden)

    Boguslaw Pierozynski

    2018-06-01

    Full Text Available This paper reports on the processes of phenol and resorcinol electrodegradation carried-out through continuous anodic dissolution of aluminum alloy and carbon steel sacrificial anodes for artificially aerated Cu-Al alloy and Cu-Fe-based galvanic (macro-corrosion cells and synthetically prepared wastewater solutions. Electrochemical experiments were carried-out by means of a laboratory size, PMMA (Poly-methyl methacrylate-made electrolyser unit, where significant degrees of phenol (10–89% and resorcinol (13–37% decomposition were obtained and visualized through the respective chemical/spectroscopy analyses. In addition, quantitative determination of phenol, as well as resorcinol (and possible electrodegradation products for the selected experimental conditions was performed by means of instrumental high-performance liquid chromatography/mass spectrometry analysis.

  1. Persistence of lindane in model cattle dips in sub-tropical climate of Delhi, India

    International Nuclear Information System (INIS)

    Singh, D.K.; Menon, P.; Agarwal, H.C.

    1997-01-01

    Persistence of lindane in model cattle dips under field conditions in the sub-tropical climate of Delhi was studied. In one set of experiments two model dips were utilized and filled with 200 L of water and treated with 2.37 MBq of 14 C-labelled and 4 g unlabelled lindane each. The radioactivity in water samples at zero time was estimated and considered to be 100 % (744 dpm/mL) which declined to 17.5 % (132 dpm/mL) 180 d after the treatment in Dip 1 (control dip). In the second dip 50 g of cowdung and soil were added 28 d after treatment and subsequently every time before sampling. The results in both the dips were similar indicating no effect of soil and cowdung on the persistence of lindane in the dips. The half life of lindane in water was 101 days. Lindane was extracted from water by hexane in the presence of methanol. The efficiency of this procedure was 99+ %. The main metabolises of lindane in water, identified by HPLC, were 1, 2, 4- trichlorobenzene, 1,3,5-trichlorobenzene and an unknown compound. In another experiment, 50 L of water was added to one dip which was treated with 2.90 MBq of 14 C-labelled and 1 g unlabelled lindane in 25 ml acetone. The cattle dip was recharged at monthly intervals with about 10 % of the initially applied lindane (290 kBq of 14 C labelled and 100 mg unlabelled lindane in 25 mL acetone). Soil and cow dung were added as in the first experiment. The concentration of lindane declined rapidly to 11.69 % (1.9 μg/mL, 425 dpm/mL) after the third recharge. The main metabolite was 1,2,4- trichlorobenzene which accounted for about 21 % after first and second recharge. The effect of pH ranging from 5 to 9 was also investigated. The dissipation appeared to be faster at pH 8 and comparatively slower at pH 6. (author)

  2. Magnesium alloys and graphite wastes encapsulated in cementitious materials: Reduction of galvanic corrosion using alkali hydroxide activated blast furnace slag

    Energy Technology Data Exchange (ETDEWEB)

    Chartier, D., E-mail: david.chartier@cea.fr [Commissariat à l' Energie Atomique et aux Energies Alternatives, CEA, DEN, DTCD, SPDE, F-30207 Bagnols-sur-Cèze (France); Muzeau, B. [DEN-Service d’Etude du Comportement des Radionucléides (SECR), CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette (France); Stefan, L. [AREVA NC/D& S - France/Technical Department, 1 place Jean Millier 92084 Paris La Défense (France); Sanchez-Canet, J. [Commissariat à l' Energie Atomique et aux Energies Alternatives, CEA, DEN, DTCD, SPDE, F-30207 Bagnols-sur-Cèze (France); Monguillon, C. [DEN-Service d’Etude du Comportement des Radionucléides (SECR), CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette (France)

    2017-03-15

    Highlights: • Embedded in cement, magnesium is corroded by residual water present in porosity of the matrix. • Corrosion is enhanced by galvanic phenomenon when magnesium is in contact with graphite. • Galvanic corrosion of magnesium in contact with graphite debris is shown to be severe with ordinary Portland cement. • Galvanic corrosion is significantly lowered in high alkali medium such as sodium hydroxide. • Sodium hydroxide activated blast furnace slag is a convenient binder to embed magnesium. - Abstract: Magnesium alloys and graphite from spent nuclear fuel have been stored together in La Hague plant. The packaging of these wastes is under consideration. These wastes could be mixed in a grout composed of industrially available cement (Portland, calcium aluminate…). Within the alkaline pore solution of these matrixes, magnesium alloys are imperfectly protected by a layer of Brucite resulting in a slow corrosion releasing hydrogen. As the production of this gas must be considered for the storage safety, and the quality of wasteform, it is important to select a cement matrix capable of lowering the corrosion kinetics. Many types of calcium based cements have been tested and most of them have caused strong hydrogen production when magnesium alloys and graphite are conditioned together because of galvanic corrosion. Exceptions are binders based on alkali hydroxide activated ground granulated blast furnace slag (BFS) which are presented in this article.

  3. Magnesium alloys and graphite wastes encapsulated in cementitious materials: Reduction of galvanic corrosion using alkali hydroxide activated blast furnace slag

    International Nuclear Information System (INIS)

    Chartier, D.; Muzeau, B.; Stefan, L.; Sanchez-Canet, J.; Monguillon, C.

    2017-01-01

    Highlights: • Embedded in cement, magnesium is corroded by residual water present in porosity of the matrix. • Corrosion is enhanced by galvanic phenomenon when magnesium is in contact with graphite. • Galvanic corrosion of magnesium in contact with graphite debris is shown to be severe with ordinary Portland cement. • Galvanic corrosion is significantly lowered in high alkali medium such as sodium hydroxide. • Sodium hydroxide activated blast furnace slag is a convenient binder to embed magnesium. - Abstract: Magnesium alloys and graphite from spent nuclear fuel have been stored together in La Hague plant. The packaging of these wastes is under consideration. These wastes could be mixed in a grout composed of industrially available cement (Portland, calcium aluminate…). Within the alkaline pore solution of these matrixes, magnesium alloys are imperfectly protected by a layer of Brucite resulting in a slow corrosion releasing hydrogen. As the production of this gas must be considered for the storage safety, and the quality of wasteform, it is important to select a cement matrix capable of lowering the corrosion kinetics. Many types of calcium based cements have been tested and most of them have caused strong hydrogen production when magnesium alloys and graphite are conditioned together because of galvanic corrosion. Exceptions are binders based on alkali hydroxide activated ground granulated blast furnace slag (BFS) which are presented in this article.

  4. Effect of Initial Iron Content in a Zinc Bath on the Dissolution Rate of Iron During a Hot Dip Galvanizing Process

    Science.gov (United States)

    Lee, Sang Myung; Lee, Suk Kyu; Paik, Doo-Jin; Park, Joo Hyun

    2017-04-01

    The mechanism of iron dissolution and the effect of initial Fe content in a Zn bath on the dissolution rate of iron were investigated using a finger rotating method (FRM). When the initial iron content, [Fe]°, in the zinc bath was less than the solubility limit, the iron content in the zinc bath showed a rapid increase, whereas a moderate increase was observed when [Fe]° was close to the solubility limit. Based on Eisenberg's kinetic model, the mass transfer coefficient of iron in the present experimental condition was calculated to be k M = 1.2 × 10-5 m/s, which was similar to the results derived by Giorgi et al. under industrial practice conditions. A dissolution of iron occurred even when the initial iron content in the zinc bath was greater than the solubility limit, which was explained by the interfacial thermodynamics in conjunction with the morphology of the surface coating layer. By analyzing the diffraction patterns using TEM, the outermost dendritic-structured coating layer was confirmed as FeZn13 ( ζ). In order to satisfy the local equilibrium based on the Gibbs-Thomson equation, iron in the dendrite-structured phase spontaneously dissolved into the zinc bath, resulting in the enrichment of iron in front of the dendrite tip. Through the diffusion boundary layer in front of the dendritic-structured layer, dissolved Fe atoms diffused out and reacted with Zn and small amounts of Al, resulting in the formation of dross particles such as FeZn10Al x ( δ). It was experimentally confirmed that the smaller the difference between the initial iron content in the zinc bath and the iron solubility limit at a given temperature, the lower the number of formed dross particles.

  5. Anticorrosive Behavior and Porosity of Tricationic Phosphate and Zirconium Conversion Coating on Galvanized Steel

    Science.gov (United States)

    Velasquez, Camilo S.; Pimenta, Egnalda P. S.; Lins, Vanessa F. C.

    2018-05-01

    This work evaluates the corrosion resistance of galvanized steel treated with tricationic phosphate and zirconium conversion coating after painting, by using electrochemical techniques, accelerated and field corrosion tests. A non-uniform and heterogeneous distribution of zirconium on the steel surface was observed due to preferential nucleation of the zirconium on the aluminum-rich sites on the surface of galvanized steel. The long-term anti-corrosion performance in a saline solution was better for the phosphate coating up to 120 days. The coating capacitance registered a higher increase for the zirconium coatings than the phosphate coatings up to 120 days of immersion. This result agrees with the higher porosity of zirconium coating in relation to the phosphate coating. After 3840 h of accelerated corrosion test, and after 1 year of accelerated field test, zirconium-treated samples showed an average scribe delamination length higher than the phosphate-treated samples.

  6. Microstructure and Corrosion Resistance Property of a Zn-AI-Mg Alloy with Different Solidification Processes

    Directory of Open Access Journals (Sweden)

    Jiang Guang-rui

    2017-01-01

    Full Text Available Zn-Al-Mg alloy coating attracted much attention due to its high corrosion resistance properties, especially high anti-corrosion performance at the cut edge. As the Zn-Al-Mg alloy coating was usually produced by hot-dip galvanizing method, solidification process was considered to influence its microstructure and corrosion properties. In this work, a Zn-Al-Mg cast alloy was melted and cooled to room temperature with different solidification processes, including water quench, air cooling and furnace cooling. Microstructure of the alloy with different solidification processes was characterized by scanning electron microscopy (SEM. Result shows that the microstructure of the Zn-Al-Mg alloy are strongly influenced by solidification process. With increasing solidification rate, more Al is remained in the primary crystal. Electrochemical analysis indicates that with lowering solidification rate, the corrosion current density of the Zn-Al-Mg alloy decreases, which means higher corrosion resistance.

  7. Novel dip-pen nanolithography strategies for nanopatterning

    NARCIS (Netherlands)

    Wu, C.C.

    2010-01-01

    Dip-pen nanolithography (DPN) is an atomic force microscopy (AFM)-based lithography technique offering the possibility of fabricating patterns with feature sizes ranging from micrometers to tens of nanometers, utilizing either top-down or bottom-up strategies. Although during its early development

  8. Hot flashes and sleep in women.

    Science.gov (United States)

    Moe, Karen E

    2004-12-01

    Sleep disturbances during menopause are often attributed to nocturnal hot flashes and 'sweats' associated with changing hormone patterns. This paper is a comprehensive critical review of the research on the relationship between sleep disturbance and hot flashes in women. Numerous studies have found a relationship between self-reported hot flashes and sleep complaints. However, hot flash studies using objective sleep assessment techniques such as polysomnography, actigraphy, or quantitative analysis of the sleep EEG are surprisingly scarce and have yielded somewhat mixed results. Much of this limited evidence suggests that hot flashes are associated with objectively identified sleep disruption in at least some women. At least some of the negative data may be due to methodological issues such as reliance upon problematic self-reports of nocturnal hot flashes and a lack of concurrent measures of hot flashes and sleep. The recent development of a reliable and non-intrusive method for objectively identifying hot flashes during the night should help address the need for substantial additional research in this area. Several areas of clinical relevance are described, including the effects of discontinuing combined hormone therapy (estrogen plus progesterone) or estrogen-only therapy, the possibility of hot flashes continuing for many years after menopause, and the link between hot flashes and depression.

  9. Continentward-Dipping Normal Faults, Boudinage and Ductile Shear at Rifted Passive Margins

    Science.gov (United States)

    Clerc, C. N.; Ringenbach, J. C.; Jolivet, L.; Ballard, J. F.

    2017-12-01

    Deep structures resulting from the rifting of the continental crust are now well imaged by seismic profiles. We present a series of recent industrial profiles that allow the identification of various rift-related geological processes such as crustal boudinage, ductile shear of the base of the crust and low-angle detachment faulting. Along both magma-rich and magma-poor rifted margins, we observe clear indications of ductile deformation of the deep continental crust. Large-scale shallow dipping shear zones are identified with a top-to-the-continent sense of shear. This sense of shear is consistent with the activity of the Continentward-Dipping Normal Faults (CDNF) that accommodate the extension in the upper crust. This pattern is responsible for an oceanward migration of the deformation and of the associated syn-tectonic deposits (sediments and/or volcanics). We discuss the origin of the Continentward-Dipping Normal Faults (CDNF) and investigate their implications and the effect of sediment thermal blanketing on crustal rheology. In some cases, low-angle shear zones define an anastomosed pattern that delineates boudin-like structures that seem to control the position and dip of upper crustal normal faults. We present some of the most striking examples from several locations (Uruguay, West Africa, South China Sea…), and discuss their rifting histories that differ from the classical models of oceanward-dipping normal faults.

  10. Optical properties of titanium di-oxide thin films prepared by dip coating method

    Science.gov (United States)

    Biswas, Sayari; Rahman, Kazi Hasibur; Kar, Asit Kumar

    2018-05-01

    Titanium dioxide (TiO2) thin films were prepared by sol-gel dip coating method on ITO coated glass substrate. The sol was synthesized by hydrothermal method at 90°C. The sol was then used to make TiO2 films by dip coating. After dip coating the rest of the sol was dried at 100°C to make TiO2 powder. Thin films were made by varying the number of dipping cycles and were annealed at 500°C. XRD study was carried out for powder samples that confirms the formation of anatase phase. Transmission spectra of thin films show sharp rise in the violet-ultraviolet transition region and a maximum transmittance of ˜60%. Band gap of the prepared films varies from 3.15 eV to 3.22 eV.

  11. Numerical prediction of a dip effect in the critical current density

    International Nuclear Information System (INIS)

    Al Khawaja, U.; Benkraouda, M.; Obaidat, I.M.

    2007-01-01

    We have conducted extensive series of molecular dynamic simulations on the properties of the critical current density in systems with periodic square arrays of pinning sites. The density of the pinning sites was kept fixed while the density of vortices, pinning strength, and temperature were varied several times. At zero temperature, we have observed a substantial dip in the critical current density that occurs only at a fixed value of the vortex density and for specific values of pinning strength. We have found that the occurrence of the dip depends mainly on the initial positions of the vortices with respect to the positions of the pinning sites. At the dip, we have found that the interstitial vortices form moving channels leading to the observed drop in the critical current density

  12. Analysis of Mechanical Stresses Due to Voltage Dips in Fixed-Speed Wind Turbines

    DEFF Research Database (Denmark)

    Veluri, Badrinath; Santos-Martin, David; Jensen, Henrik Myhre

    2011-01-01

    stresses transients that may have a detrimental effect on the fatigue life of drivetrain system due to voltage dips. A rainflow cycle counting method for the stress history during the voltage dip event, analyses mean and amplitudes of the counted cycles, their occurrence moment and time of duration.......Voltage dips due to electrical grid faults generate transients of the generator electromagnetic torque which result in significant high stresses and noticeable vibrations for the wind turbine mechanical system. These events may also have a detrimental effect on the fatigue life of important...

  13. Effect of Plastic Hot Deformation on the Hardness and Continuous Cooling Transformations of 22MnB5 Microalloyed Boron Steel

    Science.gov (United States)

    Barcellona, A.; Palmeri, D.

    2009-05-01

    The strains, transformation temperatures, microstructure, and microhardness of a microalloyed boron and aluminum precoated steel, which has been isothermally deformed under uniaxial tensile tests, have been investigated at temperatures between 873 and 1223 K, using a fixed strain rate value of 0.08 s-1. The effect of each factor, such as temperature and strain value, has been later valued considering the shift generated on the continuous cooling transformation (CCT) diagram. The experimental results consist of the starting temperatures that occur for each transformation, the microhardness values, and the obtained microstructure at the end of each thermomechanical treatment. All the thermomechanical treatments were performed using the thermomechanical simulator Gleeble 1500. The results showed that increasing hot prestrain (HPS) values generate, at the same cooling rate, lower hardness values; this means that the increasing of HPS generates a shift of the CCT diagram toward a lower starting time for each transformation. Therefore, high values of hot deformations during the hot stamping process require a strict control of the cooling process in order to ensure cooling rate values that allow maintaining good mechanical component characteristics. This phenomenon is amplified when the prestrain occurs at lower temperatures, and thus, it is very sensitive to the temperature level.

  14. Continuously tunable solution-processed organic semiconductor DFB lasers pumped by laser diode

    DEFF Research Database (Denmark)

    Klinkhammer, Sönke; Liu, Xin; Huska, Klaus

    2012-01-01

    The fabrication and characterization of continuously tunable, solution-processed distributed feedback (DFB) lasers in the visible regime is reported. Continuous thin film thickness gradients were achieved by means of horizontal dipping of several conjugated polymer and blended small molecule solu...

  15. Anti-double dipping rules for federal tax incentives

    Energy Technology Data Exchange (ETDEWEB)

    Ing, E.T.C. [Law Office of Edwin T.C. Ing, Washington, DC (United States)

    1997-12-31

    Political as well as technological changes are now reshaping the electric utility industry. While accommodating these changes, state legislative and regulatory agencies have the opportunity to promote public policies. In this regard, various state entities are evaluating appropriate incentives for renewable energy development so as to introduce greater competition in electric generation. For example, the California legislature is considering a supplemental production payment and the State of Iowa has instituted a low-interest loan program for wind and other alternative energy generation. By complementing the existing federal tax incentives, state incentives can spur the wind industry`s growth. If structured in the wrong way, however, state assistance programs will undercut the value of the federal tax incentives. The federal anti-double dipping rules apply to certain state programs. If a developer utilizes the wrong type of state assistance for a wind project, the anti-double dipping rules will reduce the federal tax incentives and this in turn will decrease the project`s profitability. Rather than suffer these results, very few if any developer will use the state program. Despite the time and effort a state may expend to enact a program for alternative energy development, the state assistance will be ineffectual. This paper reviews the counterproductive results which state assistance can have on a wind project because of the federal anti-double dipping rules.

  16. Synthesis and electrochemical properties of composite galvanic Ni with carbon nanomaterials and PVD Mo coatings

    International Nuclear Information System (INIS)

    Drozdovich, V.B.; Chayeuski, V.V.; Zhdanok, S.A.; Barkovskaya, M.M.

    2011-01-01

    Double layer coatings Ni – Mo were obtained by electrolytic deposition of galvanic Ni and following arc PVD deposition of molybdenum. The ion plating coatings Mo on Ni foil and composition electrolytic Ni coatings with carbon nanomaterials (CNM) deposited on mild steel has been also investigated. Composite galvanic Ni coatings with CNM and ion plating coatings Mo contain separately obtained cubic α-Mo phase as well as fragmentary solid solution Mo in Ni. Such coatings exclude hydrogenation of Ni foundation in alkaline solution and possess enlarged electrocatalytic properties while emitting hydrogen and oxygen. Availability of carbon based nanomaterials in combined coatings is cause of an active absorption hydrogen after cathodic polarization. A formation on the surface layer of nanostructure solid solution (Ni, Mo) after compression plasma flows treatment with fixed parameters of patterns Mo/Ni/ mild steel take place. (authors)

  17. Separation of cations of heavy metalsfrom concentrated galvanic drains

    Directory of Open Access Journals (Sweden)

    L. P. Bondareva

    2018-01-01

    Full Text Available When applying galvanic coatings, soluble salts of heavy metals such as iron, copper, nickel, zinc, cadmium, chromium and other metals are used, toxic cations enter the water, with subsequent migration to the biosphere. To date, many methods have been developed for cleaning galvanic sewage, which cannot be considered sufficiently effective. The joint sorption of divalent cations of copper, nickel and cadmium from concentrated aqueous solutions was investigated. Calculation and experimental methods were used to determine the separation conditions of the bivalent ion systems that differed and close in sorption properties on the aminophosphonic polyampholyte Purolite S950 in a natrium form. It is shown that the cadmium (II cations can be isolated from solutions containing copper (II or nickel (II cations even at the height of the sorption layer of 0.13 m due to the difference in the defining characteristics of the cations. This layer height can be used not only in a chromatographic column, but also in a concentrating cartridge. Separation of the copper (II and nickel (II close to the sorption properties requires an absorbing layer of 0.76 m, which can only be used in a chromatographic column, but not for a concentrating cartridge. In this paper, the degrees of ion separation in various sorption conditions are calculated. The applicability of the conductometric method for controlling the ion exchange process is shown not only when the free cations are isolated from aqueous solutions but also bound to complexes.

  18. Investigation of Dip-Coating Parameters Effect on The Performance of Alumina-Polydimethylsiloxane Nanofiltration Membranes for Desalination

    OpenAIRE

    Mohammad Hadi Yousefi; Mohamad Mehdi Zerafat; Majid Shokri Doodeji; Samad Sabbaghi

    2017-01-01

    The objective of this work is to investigate the effect of dip-coating parameters on the performance of Alumina-PDMS hybrid nanofiltration membranes for water desalination. Ceramic supports used in this work were prepared with a 340 nm average pore size and 34% total porosity. The aim is to determine optimum conditions of dipping time, PDMS concentration, and withdrawal speed in order to achieve high rejection and flux values. Dip-coating parameters were considered as dipping time (60 - 120 s...

  19. Galvanic Corrosion among Different Combination of Orthodontic Archwires and Stainless Steel Brackets

    Directory of Open Access Journals (Sweden)

    Farzin Heravi

    2014-06-01

    Full Text Available Introduction: The aim of this study was to assess the galvanic behavior of different bracket and archwire combinations that are commonly used in orthodontic treatments. Methods: Three types of orthodontic archwires with a diameter of 0.016×0.022 inch and 80 standard edgewise maxillary central incisor brackets were selected. Three groups consisted of different wire-bracket couples and one group was just brackets as a control group. Each group had five samples. Four brackets were then connected to each wire by elastic bands made from electrochemically neutral material. The samples were immersed into capped containers of Fusayama-Meyer artificial saliva. After six weeks, the released nickel ions were quantified via ion absorption technique. The mean and the standard deviation of all four groups were calculated and the data were compared together with Kruskal-Wallis non-parametric statistical test. Results: The highest concentration of released nickel ions was for bracket+ steel archwire and the least for the bracket without archwire. Conclusion: There were not significant differences among experimental groups, so it could be concluded that galvanic corrosion would not be a serious consideration through orthodontic treatment.  

  20. 9 CFR 72.13 - Permitted dips and procedures.

    Science.gov (United States)

    2010-01-01

    ... proprietary brands of permitted dips—as well the use of compressed air, vat management techniques, and other... maintained and that under actual field conditions the dipping of cattle with a solution of definite strength...