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Sample records for hydrogen permeation alloys

  1. Hydrogen permeation inhibition by zinc-nickel alloy plating on steel XC68

    International Nuclear Information System (INIS)

    El Hajjami, A.; Gigandet, M.P.; De Petris-Wery, M.; Catonne, J.C.; Duprat, J.J.; Thiery, L.; Raulin, F.; Starck, B.; Remy, P.

    2008-01-01

    The inhibition of hydrogen permeation and barrier effect by zinc-nickel plating was investigated using the Devanathan-Stachurski permeation technique. The hydrogen permeation and hydrogen diffusion for the zinc-nickel (12-15%) plating on steel XC68 is compared with zinc and nickel. Hydrogen permeation and hydrogen diffusion were followed as functions of time at current density applied (cathodic side) and potential permanent (anodic side). The hydrogen permeation inhibition for zinc-nickel is intermediate to that of nickel and zinc. This inhibition was due to nickel-rich layer effects at the Zn-Ni alloy/substrate interface, is shown by GDOES. Zinc-nickel plating inhibited the hydrogen diffusion greater as compared to zinc. This diffusion resistance was due to the barrier effect caused by the nickel which is present at the interface and transformed the hydrogen atomic to Ni 2 H compound, as shown by GIXRD.

  2. Hydrogen permeation inhibition by zinc-nickel alloy plating on steel XC68

    Energy Technology Data Exchange (ETDEWEB)

    El Hajjami, A. [Institut UTINAM, UMR CNRS 6213, Sonochimie et Reactivite des Surfaces, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon Cedex (France); Coventya S.A.S., 51 rue Pierre, 92588 Clichy Cedex (France); Gigandet, M.P. [Institut UTINAM, UMR CNRS 6213, Sonochimie et Reactivite des Surfaces, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon Cedex (France)], E-mail: marie-pierre.gigandet@univ-fcomte.fr; De Petris-Wery, M. [Institut Universitaire de Technologie d' Orsay, Universite Paris XI, Plateau de Moulon, 91400 Orsay (France); Catonne, J.C. [Professeur Honoraire du Conservatoire national des arts et metiers (CNAM), Paris (France); Duprat, J.J.; Thiery, L.; Raulin, F. [Coventya S.A.S., 51 rue Pierre, 92588 Clichy Cedex (France); Starck, B.; Remy, P. [Lisi Automotive, 28 faubourg de Belfort, BP 19, 90101 Delle Cedex (France)

    2008-12-30

    The inhibition of hydrogen permeation and barrier effect by zinc-nickel plating was investigated using the Devanathan-Stachurski permeation technique. The hydrogen permeation and hydrogen diffusion for the zinc-nickel (12-15%) plating on steel XC68 is compared with zinc and nickel. Hydrogen permeation and hydrogen diffusion were followed as functions of time at current density applied (cathodic side) and potential permanent (anodic side). The hydrogen permeation inhibition for zinc-nickel is intermediate to that of nickel and zinc. This inhibition was due to nickel-rich layer effects at the Zn-Ni alloy/substrate interface, is shown by GDOES. Zinc-nickel plating inhibited the hydrogen diffusion greater as compared to zinc. This diffusion resistance was due to the barrier effect caused by the nickel which is present at the interface and transformed the hydrogen atomic to Ni{sub 2}H compound, as shown by GIXRD.

  3. Peculiarities of hydrogen permeation through Zr–1%Nb alloy and evaluation of terminal solid solubility

    Energy Technology Data Exchange (ETDEWEB)

    Denisov, E.A.; Kompaniets, M.V.; Kompaniets, T.N., E-mail: tkompaniets@spbu.ru; Bobkova, I.S.

    2016-04-15

    Hydrogen permeation through Zr–1%Nb alloy was studied at the temperature below the temperature of α-β transition. Analysis of the transient permeation curves from a closed volume in a surface limited regime allowed to determine total and mobile hydrogen concentrations. At the mobile hydrogen concentration of 4.3 at% a part of the absorbed hydrogen is cut out of permeation process. Increase of the mobile hydrogen concentration in α-phase of Zr–1%Nb alloy is ceasing at the concentration of (5.5 ± 0.3) at%, which is the maximum possible concentration of the mobile hydrogen in α-phase of the studied alloy. From this moment on all absorbed hydrogen is spent on hydride formation. The obtained results are compared with those obtained by means of traditional techniques for terminal solid solubility determination.

  4. A study of hydrogen permeation in aluminum alloy treated by various oxidation processes

    International Nuclear Information System (INIS)

    Song Wenhai; Long Bin

    1997-01-01

    A set of oxide coatings was formed on the surface of an Al alloy (wt%: Fe, 0.24; Si, 1.16; Cu, 0.05-0.2; Zn, 0.1; Al, residual) by means of various oxidation processes. The hydrogen permeability through the aluminum alloy and its coating materials was determined by a vapor phase permeation technique at temperatures ranging from 400 to 500 C using high-purity H 2 (99.9999%) gas with an upstream hydrogen pressure of 10 4 -10 5 Pa. The experimental results show that the hydrogen permeability through aluminum oxide coating is 100-2000 times lower than that through the aluminum alloy substrate. This means that the aluminum oxide is a significant hydrogen permeation barrier. A high hydrogen permeation resistance was observed in an oxide layer prefilmed in 200 C water, while an anodized aluminum oxide film had a less obstructive effect, possibly caused by the porous structure of the anodic oxide. The hydrogen permeability through films of aluminum oxide was not a simple function of the aluminum-oxide phase configuration. (orig.)

  5. Hydrogen permeation in FeCrAl alloys for LWR cladding application

    Science.gov (United States)

    Hu, Xunxiang; Terrani, Kurt A.; Wirth, Brian D.; Snead, Lance L.

    2015-06-01

    FeCrAl, an advanced oxidation-resistant iron-based alloy class, is a highly prevalent candidate as an accident-tolerant fuel cladding material. Compared with traditional zirconium alloy fuel cladding, increased tritium permeation through FeCrAl fuel cladding to the primary coolant is expected, raising potential safety concerns. In this study, the hydrogen permeability of several FeCrAl alloys was obtained using a static permeation test station, which was calibrated and validated using 304 stainless steel. The high hydrogen permeability of FeCrAl alloys leads to concerns with respect to potentially significant tritium release when used for fuel cladding in LWRs. The total tritium inventory inside the primary coolant of a light water reactor was quantified by applying a 1-dimensional steady state tritium diffusion model to demonstrate the dependence of tritium inventory on fuel cladding type. Furthermore, potential mitigation strategies for tritium release from FeCrAl fuel cladding were discussed and indicate the potential for application of an alumina layer on the inner clad surface to serve as a tritium barrier. More effort is required to develop a robust, economical mitigation strategy for tritium permeation in reactors using FeCrAl clad fuel assemblies.

  6. Ratio of dialytic coefficients of hydrogen and tritium in permeation through palladium alloy film

    International Nuclear Information System (INIS)

    Fujita, Haruyuki; Fujita, Kunio; Sakamoto, Hiroshi; Higashi, Kunio; Okada, Sakae.

    1982-01-01

    The dialytic coefficient for hydrogen is especially large in palladium and its alloys. Recently, with the research on fusion reactors, the dialytic coefficient of tritium permeating through solids and its isotopic effect have been the object of interest. The ratio of the dialytic coefficients of tritium and hydrogen has been usually assumed to be 3. The measurement of the dialytic coefficient in solids using pure tritium is practically difficult. Therefore, the authors carried out the experiment to determine the ratio of the dialytic coefficients of pure T 2 and pure H 2 by permeating the mixed gas of T and H through Pd-Au-Ag alloy. The mixed hydrogen gas was filled in a separation cell containing a palladium alloy tube, and the separation factor of tritium and hydrogen was measured by changing pressure, flow rate and temperature. The separation factor depends mainly on the relative dialytic coefficients of tritium and hydrogen, therefore, the ratio of dialytic coefficients can be determined by the simple analysis of the experimental results. This experimental method is suitable to determine the relative value of dialytic coefficients, and the obtained ratio was about 2.1. (Kako, I.)

  7. Hydrogen and deuterium permeation in copper alloys, copper--gold brazing alloys, gold, and the in situ growth of stable oxide permeation barriers

    International Nuclear Information System (INIS)

    Begeal, D.R.

    1978-01-01

    The deuterium permeation through several copper alloys has been measured over a temperature range of 550 to 830 K using the membrane technique. In some cases, the hydrogen permeability was also measured. The results were divided into three categories: common alloys, gold alloys, and stable oxide forming alloys. Common alloys which showed typical bulk metallic diffusion with litle change in the permeation activation energy as compared to copper (77 kJ/mol for D 2 ) were: (additions are in weight percent) 5% Sn, 2.3% U, 0.15% Zr, 4% Sn+4% Pb+4% Zn, 3% Si, and 7% Al+2% Fe. Compared to copper, the D 2 permeability at 573 K was reduced by factors of 2.0, 2.7, 4.5, 5.3, 5.9, and 7.0, respectively. A series of gold--copper alloys including pure gold, 80% Au, 50% Au, 49% Au, and 35% Au also showed typical bulk metallic diffusion with a trend of decreasing permeability (increasing activation energies for permeation) with increasing gold content. There were also pronounced inflections or shifts in the permeability at approx.370 0 C, or about the order--disorder transition for Cu 3 Au and CuAu, for the 80% and 50% alloys. Two alloys did not exhibit bulk metallic permeation behavior and the permeabiltiy was in fact controlled by surface oxide layers. It was found that a layer of beryllium oxide could be formed on Cu+2% Be and a layer of aluminum oxide could be formed on Cu+7% Al+2% Si. As compared to 0.25 mm-thick copper, the deuterium permeability at 500 0 C was reduced by a factor of approx.250 for Cu--Be and approx.1000 for Cu--Al--Si. The activation energies for deuterium permeation were 98 kJ/mol and 132 kJ/mol, respectively. The mechanism for the oxide growth is the high-temperature hydrogen reduction of nearby less stable oxides, simultaneous with oxidation of the active metal, Be or Al, by trace amounts of water in the hydrogen. Ion microprobe mass analysis identified the oxide layers as containing beryllium or aluminum but not containing copper

  8. Influence of the C content on the permeation of hydrogen in Fe alloys with low contents of C

    Directory of Open Access Journals (Sweden)

    I. Peñalva

    2016-12-01

    The experimental permeation results were analyzed using a non-linear least square fitting. The final resulting values of the permeability were paired off in order to determine the effect of the C content: pure Fe versus FeC, FeP versus FePC and Fe10%Cr versus Fe10%CrC. According to the results, the influence of the metallurgical composition of C in Fe alloys on the permeability of hydrogen is discussed together with the synergistic effects caused by the presence of P and Cr.

  9. Hydrogen permeation properties of Pd-coated V89.8Cr 10Y0.2 alloy membrane using WGS reaction gases

    KAUST Repository

    Jeon, Sungil

    2013-05-01

    The influence of co-existing gases on the hydrogen permeation was studied through a Pd-coated V89.8Cr10Y0.2 alloy membrane. Preliminary hydrogen permeation experiments have been confirmed that hydrogen flux was 6.26 ml/min/cm2 for a Pd-coated V 89.8Cr10Y0.2 alloy membrane (thick: 0.5 mm) using pure hydrogen as feed gas. Also, the hydrogen permeation flux decreased with decrease of hydrogen partial pressure at constant pressure when H 2/CO2 and H2/CO2/H2S mixture applied as feed gas respectively and permeation fluxes were satisfied with Sievert\\'s law in different feed conditions. It was found from XRD and SEM results after permeation test that the Pd-coated V89.8Cr 10Y0.2 alloy membrane had good stability and durability for various mixture feeding conditions. Copyright © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  10. Hydrogen permeation properties of Pd-coated V89.8Cr 10Y0.2 alloy membrane using WGS reaction gases

    KAUST Repository

    Jeon, Sungil; Park, Junghoon

    2013-01-01

    The influence of co-existing gases on the hydrogen permeation was studied through a Pd-coated V89.8Cr10Y0.2 alloy membrane. Preliminary hydrogen permeation experiments have been confirmed that hydrogen flux was 6.26 ml/min/cm2 for a Pd-coated V 89.8Cr10Y0.2 alloy membrane (thick: 0.5 mm) using pure hydrogen as feed gas. Also, the hydrogen permeation flux decreased with decrease of hydrogen partial pressure at constant pressure when H 2/CO2 and H2/CO2/H2S mixture applied as feed gas respectively and permeation fluxes were satisfied with Sievert's law in different feed conditions. It was found from XRD and SEM results after permeation test that the Pd-coated V89.8Cr 10Y0.2 alloy membrane had good stability and durability for various mixture feeding conditions. Copyright © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  11. Hydrogen permeation through metallic foils

    International Nuclear Information System (INIS)

    Bernardi, M.I.B.; Rodrigues, J.A.

    1987-01-01

    The process of electrolytic permeation of hydrogen through metallic foils is studied. A double electrolytic cell, in glass, in which the two compartments of reaction are separated by a metallic foil to be studied, was built. As direct result, the hydrogen diffusion coefficient in the metal is obtained. The hydrogen diffusion coefficients in the palladium and, in austenitic stainless steels 304 and 304 L, used in the Angra-1 reactor, were obtained. Samples of stainless steels with and without welding, were used. (Author) [pt

  12. Study of the bipolar electrolysis of the tritiated water applied to the hydrogen isotopes separation by electrochemical permeation threw Pd-Ag alloy membranes

    International Nuclear Information System (INIS)

    Heinze, S.

    2000-01-01

    The objective of the study is to enrich waters of poor tritium concentration, by electrolysis in the same time of an hydrogen emission of low activity. In this framework the hydrogen electrochemical permeation threw Pd-Ag alloy membranes has been used. The first part of the study concerns the hydrogen and the deuterium diffusion threw these membranes. The activation and the thermal treatments influence have been studied. A relation between the membrane microstructure and the diffusion mechanism has been proposed. The second part of the study is devoted to the hydrogen gate mechanism determination in the membrane by impedance spectroscopy. The last part concerns the determination of the isotopic separation factor hydrogen-deuterium. Experimental results agree the calculated theoretical data. The operation of an operational membrane cell has been simulated and the process feasibility has been proved. (A.L.B.)

  13. Hydrogen permeation preventive structural materials

    International Nuclear Information System (INIS)

    Fukushima, Kimichika; Nakahigashi, Shigeo; Imura, Masashi; Terasawa, Michitaka; Ebisawa, Katsuyuki.

    1986-01-01

    Purpose: To provide highly practical wall materials for use in thermonuclear reactors capable of effectively preventing the permeation of hydrogen isotopes such as tritium thereby preventing the contamination of coolants. Constitution: Helium gas is injected into or at the surface of base materials comprising stainless steel plates to form a helium gas region. Alternatively, boron, nitrogen or the compound thereof having a greater helium forming nuclear reaction cross section than that of the base materials is mixed or injected into the base material to form the helium gas region through (n,α) reaction under neutron irradiation. Since the helium gas region constitutes a diffusion barrier for the tritium as the hydrogen isotope, the permeation amount of tritium is significantly suppressed. Helium gas bubbles or lattice defects are formed in the helium gas region under the neutron irradiation, by which the hydrogen isotope capturing effect can also be effected. In this way, permeation of the hydrogen isotope, contamination of the coolants, etc. can be prevented to provide great practical effectives. (Kawakami, Y.)

  14. Permeation of hydrogen through metal membranes

    International Nuclear Information System (INIS)

    Wienhold, P.; Rota, E.; Waelbroeck, F.; Winter, J.; Banno, Tatsuya.

    1986-08-01

    Experiments show that the permeant flux of hydrogen through a metal membrane at low driving pressures ( r is introduced into the model as a new material constant and the rate equations are given. After the description of the wall pump effect, a variety of different limiting cases are discussed for a symmetrical permeation membrane. This is modified to the asymmetric case and to the influence of particle implantation. The permeation number W turns out to be a dimensionless quantity which characterizes the permeation range and predicts the permeant flux in steady state. (orig.)

  15. Permeation of deuterium implanted into vanadium alloys

    International Nuclear Information System (INIS)

    Anderl, R.A.; Longhurst, G.R.; Struttmann, D.A.

    1986-05-01

    Permeation of deuterium through the vanadium alloy, V-15Cr-5Ti, was investigated using 3-keV, D 3 + ion beams from a small accelerator. The experiments consisted of measurements of the deuterium reemission and permeation rates as a function of implantation fluence for 0.5-mm thick specimens heated to tempertures from 623 to 823 0 K. Implantation-side surface characterization was made by simultaneous measurements of sputtered ions with a secondary ion mass spectrometer (SIMS). Analyses of these measurements indicate that for the experimental conditions used, the steady-state deuterium permeation flux in V-15Cr-5Ti is approximately 18% of the implantation flux. This corresponds to approximately 1000 times that seen in the ferritic steel, HT-9, under comparable conditions. Measurement of deuterium diffusivity in V-15Cr-5Ti using permeation break-through times indicates D = 1.4 x 10 -8 exp(-.11 eV/kT) (m 2 /s)

  16. Hydrogen Permeation in Cold-Rolled High-Mn Twinning-Induced Plasticity Steels

    Science.gov (United States)

    Han, Do Kyeong; Hwang, A. In; Byeon, Woo Jun; Noh, Seung Jeong; Suh, Dong-Woo

    2017-11-01

    Hydrogen permeation is investigated in cold-rolled Fe-0.6C-18Mn-(1.5Al) alloys. The hydrogen mobility is lower in cold-rolled alloys compared with annealed alloys. Al-containing alloy shows less deceleration of hydrogen mobility compared with the Al-free alloy. This is attributed to the reduced formation of mechanical twins and dislocations. Mechanical twins trap hydrogen strongly but are vulnerable to crack initiation; suppression of these is thought to be a major favorable influence of Al on hydrogen-induced mechanical degradation.

  17. Permeation barrier for lightweight liquid hydrogen tanks

    Energy Technology Data Exchange (ETDEWEB)

    Schultheiss, D.

    2007-04-16

    For the future usage of hydrogen as an automotive fuel, its on-board storage is crucial. One approach is the storage of liquid hydrogen (LH2, 20 K) in double-walled, vacuum insulated tanks. The introduction of carbon fiber reinforced plastics (CFRP) as structural material enables a high potential of reducing the weight in comparison to the state-of-the-art stainless steel tanks. The generally high permeability of hydrogen through plastics, however, can lead to long-term degradation of the insulating vacuum. The derived objective of this dissertation was to find and apply an adequate permeation barrier (liner) on CFRP. The investigated liners were either foils adhered on CFRP specimens or coatings deposited on CFRP specimens. The coatings were produced by means of thermal spraying, metal plating or physical vapor deposition (PVD). The materials of the liners included Al, Au, Cu, Ni and Sn as well as stainless steel and diamond-like carbon. The produced liners were tested for their permeation behavior, thermal shock resistance and adherence to the CFRP substrate. Additionally, SEM micrographs were used to characterize and qualify the liners. The foils, although being a good permeation barrier, adhered weakly to the substrate. Furthermore, leak-free joining of foil segments is a challenge still to be solved. The metal plating liners exhibited the best properties. For instance, no permeation could be detected through a 50 {mu}m thick Cu coating within the accuracy of the measuring apparatus. This corresponds to a reduction of the permeation gas flow by more than factor 7400 compared to uncoated CFRP. In addition, the metal platings revealed a high adherence and thermal shock resistance. The coatings produced by means of thermal spraying and PVD did not show a sufficient permeation barrier effect. After having investigated the specimens, a 170 liter CFRP tank was fully coated with 50 {mu}m Cu by means of metal plating. (orig.)

  18. Hydrogen isotope permeation in elastomeric materials

    International Nuclear Information System (INIS)

    Steinmeyer, R.H.; Braun, J.D.

    1976-01-01

    The permeabilities of elastomeric and polymeric materials to hydrogen isotopes were measured at room temperature. The technique for measuring permeation rates is based on the following constant-volume method: a fixed pressure of gas is applied to one side of the specimen to be studied and the permeability constant is determined from the observed rate of pressure increase in an initially evacuated volume on the other side of the specimen. Permeability constants for hydrogen, deuterium, and tritium were measured for Mylar, Teflon, Kapton, Saran, Buna-N, and latex rubber. Results were compared with literature values for hydrogen and deuterium where available and showed excellent agreement

  19. Hydrogen permeation resistant phosphate coatings

    International Nuclear Information System (INIS)

    McGuire, J.C.

    1979-01-01

    A method for reducing hydrogen diffusion through metal wherein the metal is coated with a phosphate-radical-containing, phosphate-glass-forming material on at least one surface thereof. The coating is then heated to at least 350 0 C to form a phosphate glass. This method is especially applicable to nuclear reactors to minimize tritium diffusion. The coating is preferably formed with a solution of phosphoric acid which may also contain compounds such as MnSO 4 , SiO 2 and Na 2 Cr 2 0 7 . (author)

  20. Hydrogen permeation resistant phosphate coatings

    International Nuclear Information System (INIS)

    McGuire, J.C.

    1979-01-01

    A method for reducing hydrogen diffusion through metal is described. The metal is coated with a phosphate-radical-containing, phosphate-glass-forming material on at least one surface. The coating is then heated to at least 350 0 C to form a phosphate glass. This method is especially applicable to nuclear reactors to minimize tritium diffusion. The coating is preferably formed with a solution of phosphoric acid which may also contain compounds such as MnSO 4 , SiO 2 and Na 2 Cr 2 O 7 . (author)

  1. Hydrogen effects in aluminum alloys

    International Nuclear Information System (INIS)

    Louthan, M.R. Jr.; Caskey, G.R. Jr.; Dexter, A.H.

    1976-01-01

    The permeability of six commercial aluminum alloys to deuterium and tritium was determined by several techniques. Surface films inhibited permeation under most conditions; however, contact with lithium deuteride during the tests minimized the surface effects. Under these conditions phi/sub D 2 / = 1.9 x 10 -2 exp (--22,400/RT) cc (NTP)atm/sup -- 1 / 2 / s -1 cm -1 . The six alloys were also tested before, during, and after exposure to high pressure hydrogen, and no hydrogen-induced effects on the tensile properties were observed

  2. Hydrogen permeation resistant layers for liquid metal reactors

    International Nuclear Information System (INIS)

    McGuire, J.C.

    1980-03-01

    Reviewing the literature in the tritium diffusion field one can readily see a wide divergence in results for both the response of permeation rate to pressure, and the effect of oxide layers on total permeation rates. The basic mechanism of protective oxide layers is discussed. Two coatings which are less hydrogen permeable than the best naturally occurring oxide are described. The work described is part of an HEDL-ANL cooperative research program on Tritium Permeation in Liquid Metal Cooled Reactors. This includes permeation work on hydrogen, deuterium, and tritium with the hydrogen-deuterium research leading to the developments presented

  3. Investigation on hydrogen permeation on heat exchanger materials in conditions of steam coal gasification

    International Nuclear Information System (INIS)

    Moellenhoff, H.

    1984-01-01

    The permeation of hydrogen through iron-based alloys of different compositions in the temperature range between 700 and 1000 0 C was examined in a laboratory fluidized bed in the conditions of steam/coal gasification. Apart from tests on bright metal samples, measurement in the gasification atmosphere at a maximum pressure of 1 bar were carried out during oxidation of the metal. Experiments in a steam/hydrogen/argon mixture with the same oxidation potential were used for comparison purposes. The hydrogen permeated through the metal sample was taken to a gas chromatograph with argon flushing gas and analyzed there. The investigations on bright steel samples of various composition showed that their permeabilities for hydrogen at temperatures around 900 0 C only differed by a maximum of ± 30%. Effective prevention of permeation is therefore not possible simply by choosing a suitable alloy. If the steels are oxidized during permeation measurements, there is a reduction of the hydrogen permeability by 2 or 3 orders of magnitude due to the oxidation process, both in the steam/coal gasification fluidized bed and in a pure steam/hydrogen/argon mixture. (orig./GG) [de

  4. Standard practice for evaluation of hydrogen uptake, permeation, and transport in metals by an electrochemical technique

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1997-01-01

    1.1 This practice gives a procedure for the evaluation of hydrogen uptake, permeation, and transport in metals using an electrochemical technique which was developed by Devanathan and Stachurski. While this practice is primarily intended for laboratory use, such measurements have been conducted in field or plant applications. Therefore, with proper adaptations, this practice can also be applied to such situations. 1.2 This practice describes calculation of an effective diffusivity of hydrogen atoms in a metal and for distinguishing reversible and irreversible trapping. 1.3 This practice specifies the method for evaluating hydrogen uptake in metals based on the steady-state hydrogen flux. 1.4 This practice gives guidance on preparation of specimens, control and monitoring of the environmental variables, test procedures, and possible analyses of results. 1.5 This practice can be applied in principle to all metals and alloys which have a high solubility for hydrogen, and for which the hydrogen permeation is ...

  5. Effect of piperidones on hydrogen permeation and corrosion ...

    Indian Academy of Sciences (India)

    corrosion inhibition. 3.5 Hydrogen permeation measurements. Hydrogen can enter into the metal during various industrial operations like melting, heat treatment, or pickling and electrochemical processes such as cathodic cleaning and electrolytic machining. Of the various sources of entry of hydrogen into the metal,.

  6. Double electrolyte sensor for monitoring hydrogen permeation rate in steels

    Energy Technology Data Exchange (ETDEWEB)

    Ouyang, Y.J. [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Department of Chemistry and Chemical Engineering, Huaihua College, Huaihua 418008 (China); Yu, G., E-mail: yuganghnu@163.co [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Ou, A.L.; Hu, L.; Xu, W.J. [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)

    2011-06-15

    Highlights: {yields} Designed an amperometric hydrogen sensor with double electrolytes. {yields} Explained the principle of determining hydrogen permeation rate. {yields} Verified good stability, reproducibility and correctness of the developed sensor. {yields} Field on-line monitoring the susceptivity of hydrogen induced cracks. - Abstract: An amperometric hydrogen sensor with double electrolytes composed of a gelatiniform electrolyte and KOH solution has been developed to determine the permeation rate of hydrogen atoms in steel equipment owing to hydrogen corrosion. The gelatiniform electrolyte was made of sodium polyacrylate (PAAS), carboxyl methyl cellulose (CMC) and 0.2 mol dm{sup -3} KOH solution. The results show that the gelatiniform electrolyte containing 50 wt.% polymers has suitable viscosity and high electrical conductivity. The consistent permeation curves were detected by the sensor of the double electrolyte and single liquid KOH electrolyte, respectively. The developed sensor has good stability and reproducibility at room temperature.

  7. Double electrolyte sensor for monitoring hydrogen permeation rate in steels

    International Nuclear Information System (INIS)

    Ouyang, Y.J.; Yu, G.; Ou, A.L.; Hu, L.; Xu, W.J.

    2011-01-01

    Highlights: → Designed an amperometric hydrogen sensor with double electrolytes. → Explained the principle of determining hydrogen permeation rate. → Verified good stability, reproducibility and correctness of the developed sensor. → Field on-line monitoring the susceptivity of hydrogen induced cracks. - Abstract: An amperometric hydrogen sensor with double electrolytes composed of a gelatiniform electrolyte and KOH solution has been developed to determine the permeation rate of hydrogen atoms in steel equipment owing to hydrogen corrosion. The gelatiniform electrolyte was made of sodium polyacrylate (PAAS), carboxyl methyl cellulose (CMC) and 0.2 mol dm -3 KOH solution. The results show that the gelatiniform electrolyte containing 50 wt.% polymers has suitable viscosity and high electrical conductivity. The consistent permeation curves were detected by the sensor of the double electrolyte and single liquid KOH electrolyte, respectively. The developed sensor has good stability and reproducibility at room temperature.

  8. Electrochemical measurement of tritium and hydrogen permeation through iron membranes

    International Nuclear Information System (INIS)

    Hagi, Hideki; Hayashi, Yasunori

    1987-01-01

    Permeation rates of tritium and hydrogen through iron were measured by the electro-chemical method in which an aqueous solution containing 3.7 x 10 12 Bq/m 3 tritium was used as a cathodic electrolyte. Tritium and hydrogen were introduced from one side of a specimen by cathodic polarization with a constant current density, while at the other side of the specimen the permeated tritium and hydrogen were extracted by potentiostatical ionization. Nearly all of the potentiostatic current on the extraction side is produced by the ionization of hydrogen, because the concentration of tritium in the cathodic electrolyte is very small. The amount of permeated hydrogen was obtained by integrating the potentiostatic current, and that of permeated tritium was determined by measuring the radioactivity of the electrolyte sampled from the anodic side. The separation factor for permeation obtained under steady state conditions (the ratio of permeation rates of hydrogen to tritium divided by the ratio of the concentration of hydrogen to tritium in the cathodic electrolyte) is 12 at 288 K. This value is independent of cathodic current density. Diffusion coefficients of tritium (D T ) and hydrogen (D H ) in iron were determined from the tritium and hydrogen permeation by using time lag technique. For annealed iron at 286 K, D T = 9 x 10 -10 m 2 /s and D H = 4 x 10 -9 m 2 /s, and for 9 % cold-worked iron at 284 K, D T = 3 x 10 -10 m 2 /s and D H = 4 x 10 -10 m 2 /s. (author)

  9. Effect of residual stresses on hydrogen permeation in iron

    International Nuclear Information System (INIS)

    Mouanga, M.; Bercot, P.; Takadoum, J.

    2010-01-01

    The effect of residual stresses on electrochemical permeation in iron membrane was investigated. Four thermal and mechanical treatments were chosen to obtain different surface states in relation to the residual stresses. Residual stresses were determined by X-ray diffraction (XRD) using the Macherauch and Mueller method. The results were completed by the microhardness measurements. For all iron membranes, compressive residual stresses were obtained. Electrochemical permeation experiments using a Devanathan and Stachurski cell were employed to determine the hydrogen permeation behaviour of the various iron membranes. The latter was charged with hydrogen by galvanostatic cathodic polarization in 0.1 M NaOH at 25 deg. C. The experimental results revealed that hydrogen permeation rate increases with increasing residual stresses introduced in iron membranes.

  10. Electrochemical measurement of tritium and hydrogen permeation through iron membranes

    International Nuclear Information System (INIS)

    Hagi, Hideki; Hayashi, Yasunori

    1988-01-01

    Permeation rates of tritium and hydrogen through iron were measured by the electrochemical method in which an aqueous solution containing 3.7 x 10 12 Bq/m 3 tritium was used as a cathodic electrolyte. Tritium and hydrogen were introduced from one side of a specimen by cathodic polarization with a constant current density, while at the other side of the specimen the permeated tritium and hydrogen were extracted by potentiostatical ionization. Nearly all of the potentiostatic current of the extraction side stands for the ionization of hydrogen, because the concentration of tritium in the cathodic electrolyte is very small. The amount of permeated hydrogen was obtained by integrating the anodic current, and that of tritium was determined by measuring the radioactivity of the electrolyte sampled from the extraction side. The separation factor for permeation obtained under steady state conditions (the ratio of permeation rates of hydrogen to tritium divided by the ratio of the concentration of hydrogen to tritium in the charging electrolyte) is 12 at 288 K. This value is independent of cathodic current density. Diffusion coefficients of tritium (D T ) and hydrogen (D H ) in iron were determined from the time lag of tritium and hydrogen permeation. For annealed specimens at 286 K, D T = 9 x 10 -10 m 2 /s and D H = 4 x 10 -9 m 2 /s, and for 9% cold-worked specimens at 284 K, D T = 3 x 10 -10 m 2 /s and D H = 4 x 10 -10 m 2 /s. (author)

  11. Studies on the permeation of hydrogen through steam generator tubes at high temperatures using an electrochemical method

    International Nuclear Information System (INIS)

    Giraudeau, F.; Yang, L.; Steward, F.R.; DeBouvier, O.

    1998-01-01

    The permeation of hydrogen through steam generator tubes at high temperatures (∼ 300 degrees C) has been studied using an electrochemical technique. With this technique, hydrogen is generated on one side of the tube and monitored on the other side. The time for the hydrogen to reach the other side is used to determine the diffusion coefficient of hydrogen in the tube. Boundary conditions at the entry and exit sides have been investigated separately. Preliminary studies were performed on Stainless Steel 316 and Nickel Alloy 800 to better understand the influence of the solution chemistry on the electrochemical evolution of hydrogen. The surface phenomena effect and the trapping effect are discussed to account for differences observed in the permeation response. The hydrogen permeation through oxides at the exit side has been studied. Two nickel alloys (Alloy 800 and Alloy 600), materials widely used for steam generator tubes, have been investigated. The tubes were prefilmed using two different treatments. The oxides were formed in dry air at high temperatures (300 degrees C to 600 degrees C), or in humid gas at 300 degrees C. The diffusion coefficients at 300 degrees C in Stainless Steel 316 and Alloy 800 were determined to be of the order of 10 -6 - 10 -7 cm 2 /s for the bare metal. This is in agreement with results obtained by gas phase permeation techniques in the literature. (author)

  12. Hydrogen in titanium alloys

    International Nuclear Information System (INIS)

    Wille, G.W.; Davis, J.W.

    1981-04-01

    The titanium alloys that offer properties worthy of consideration for fusion reactors are Ti-6Al-4V, Ti-6Al-2Sn-4Zr-2Mo-Si (Ti-6242S) and Ti-5Al-6Sn-2Zr-1Mo-Si (Ti-5621S). The Ti-6242S and Ti-5621S are being considered because of their high creep resistance at elevated temperatures of 500 0 C. Also, irradiation tests on these alloys have shown irradiation creep properties comparable to 20% cold worked 316 stainless steel. These alloys would be susceptible to slow strain rate embrittlement if sufficient hydrogen concentrations are obtained. Concentrations greater than 250 to 500 wppm hydrogen and temperatures lower than 100 to 150 0 C are approximate threshold conditions for detrimental effects on tensile properties. Indications are that at the elevated temperature - low hydrogen pressure conditions of the reactors, there would be negligible hydrogen embrittlement

  13. Vanadium alloy membranes for high hydrogen permeability and suppressed hydrogen embrittlement

    International Nuclear Information System (INIS)

    Kim, Kwang Hee; Park, Hyeon Cheol; Lee, Jaeho; Cho, Eunseog; Lee, Sang Mock

    2013-01-01

    The structural properties and hydrogen permeation characteristics of ternary vanadium–iron–aluminum (V–Fe–Al) alloy were investigated. To achieve not only high hydrogen permeability but also strong resistance to hydrogen embrittlement, the alloy composition was modulated to show high hydrogen diffusivity but reduced hydrogen solubility. We demonstrated that matching the lattice constant to the value of pure V by co-alloying lattice-contracting and lattice-expanding elements was quite effective in maintaining high hydrogen diffusivity of pure V

  14. Hydrogen gas driven permeation through tungsten deposition layer formed by hydrogen plasma sputtering

    International Nuclear Information System (INIS)

    Uehara, Keiichiro; Katayama, Kazunari; Date, Hiroyuki; Fukada, Satoshi

    2015-01-01

    Highlights: • H permeation tests for W layer formed by H plasma sputtering are performed. • H permeation flux through W layer is larger than that through W bulk. • H diffusivity in W layer is smaller than that in W bulk. • The equilibrium H concentration in W layer is larger than that in W bulk. - Abstract: It is important to evaluate the influence of deposition layers formed on plasma facing wall on tritium permeation and tritium retention in the vessel of a fusion reactor from a viewpoint of safety. In this work, tungsten deposition layers having different thickness and porosity were formed on circular nickel plates by hydrogen RF plasma sputtering. Hydrogen permeation experiment was carried out at the temperature range from 250 °C to 500 °C and at hydrogen pressure range from 1013 Pa to 101,300 Pa. The hydrogen permeation flux through the nickel plate with tungsten deposition layer was significantly smaller than that through a bare nickel plate. This indicates that a rate-controlling step in hydrogen permeation was not permeation through the nickel plate but permeation though the deposition layer. The pressure dependence on the permeation flux differed by temperature. Hydrogen permeation flux through tungsten deposition layer is larger than that through tungsten bulk. From analysis of the permeation curves, it was indicated that hydrogen diffusivity in tungsten deposition layer is smaller than that in tungsten bulk and the equilibrium hydrogen concentration in tungsten deposition layer is enormously larger than that in tungsten bulk at same hydrogen pressure.

  15. Hydrogen permeation behavior through F82H at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, S.; Katayama, K.; Shimozori, M.; Fukada, S. [Interdisciplinary Graduate School of Engineering Science, Kyushu University, Kyushu (Japan); Ushida, H. [Energy Science and Engineering, Faculty of Engineering, Kyushu University, Kyushu (Japan); Nishikawa, M. [Malaysia-Japan International Institute of Technology, UTM, Kuala Lumpur (Malaysia)

    2015-03-15

    F82H is a primary candidate of structural material and coolant pipe material in a blanket of a fusion reactor. Understanding tritium permeation behavior through F82H is important. In a normal operation of a fusion reactor, the temperature of F82H will be controlled below 550 C. degrees because it is considered that F82H can be used up to 30,000 hours at 550 C. degrees. However, it is necessary to assume the situation where F82H is heated over 550 C. degrees in a severe accident. In this study, hydrogen permeation behavior through F82H was investigated in the temperature range from 500 to 800 C. degrees. In some cases, water vapor was added in a sample gas to investigate an effect of water vapor on hydrogen permeation. The permeability of hydrogen in the temperature range from 500 to 700 C. degrees agreed well with the permeability reported by E. Serra et al. The degradation of the permeability by water vapor was not observed. After the hydrogen permeation reached in a steady state at 700 C. degrees, the F82H sample was heated to 800 C. degrees. The permeability of hydrogen through F82H sample which was once heated up to 800 C. degrees was lower than that of the original one. (authors)

  16. Model of diffusers / permeators for hydrogen processing

    International Nuclear Information System (INIS)

    Jacobs, W. D.; Hang, T.

    2008-01-01

    Palladium-silver (Pd-Ag) diffusers are mainstays of hydrogen processing. Diffusers separate hydrogen from inert species such as nitrogen, argon or helium. The tubing becomes permeable to hydrogen when heated to more than 250 C and a differential pressure is created across the membrane. The hydrogen diffuses better at higher temperatures. Experimental or experiential results have been the basis for determining or predicting a diffuser's performance. However, the process can be mathematically modeled, and comparison to experimental or other operating data can be utilized to improve the fit of the model. A reliable model-based diffuser system design is the goal which will have impacts on tritium and hydrogen processing. A computer model has been developed to solve the differential equations for diffusion given the operating boundary conditions. The model was compared to operating data for a low pressure diffuser system. The modeling approach and the results are presented in this paper. (authors)

  17. Permeation of "Hydromer" Film: An Elastomeric Hydrogen-Capturing Biopolymer.

    Energy Technology Data Exchange (ETDEWEB)

    Karnesky, Richard A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Friddle, Raymond William [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Whaley, Josh A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Smith, Geoffrey [New Mexico State Univ., Las Cruces, NM (United States)

    2015-12-01

    This report analyzes the permeation resistance of a novel and proprietary polymer coating for hydrogen isotope resistance that was developed by New Mexico State University. Thermal gravimetric analysis and thermal desoprtion spectroscopy show the polymer is stable thermally to approximately 250 deg C. Deuterium gas-driven permeation experiments were conducted at Sandia to explore early evidence (obtained using Brunauer - Emmett - Teller) of the polymer's strong resistance to hydrogen. With a relatively small amount of the polymer in solution (0.15%), a decrease in diffusion by a factor of 2 is observed at 100 and 150 deg C. While there was very little reduction in permeability, the preliminary findings reported here are meant to demonstrate the sensitivity of Sandia's permeation measurements and are intended to motivate the future exploration of thicker barriers with greater polymer coverage.

  18. Hydrogen diffusion, dissolution and permeation of nonmetallic solids

    International Nuclear Information System (INIS)

    Elleman, T.S.; Rao, D.; Verghese, K.; Zumwalt, L.

    1979-01-01

    A review of hydrogen diffusion, dissolution and permeation in metal oxides, carbides, nitrides, halides and hydrides is presented. Results are organized by compound and an effort has been made to resolve differences between measured results where wide disparities exist. The document has been prepared to provide needed data for the development of fusion reactor blankets but the results should be generally useful in technologies that involve interactions between hydrogen and non-metals

  19. Investigation of non-magnetic alloys for the suppression of tritium permeation. Final report

    International Nuclear Information System (INIS)

    1980-07-01

    This report describes a small (300 man hour) literature survey relating to the suppression of tritium loss by permeation through the walls of fusion reactors. The program was based on prior in-house Thermacore work to suppress hydrogen permeation into high temperature (800 0 C) heat pipes. The Thermacore approach involves selection of a steel with a small (.5 to 5%) aluminum content. The aluminum is diffused to the surface and oxidized. The present work was aimed at identification of alloys which might combine low tritium permeation with other properties desired in fusion reactor vessels, heat exchangers, lithium-handling plumbing and other components likely to contain tritium. These properties include low radiation damage, low magnetic permeability, high temperature strength, and compatibility with potential heat transfer and blanket materials. The work consisted of two tasks: Problem Definition and Literature Search and Analysis

  20. Study on low temperature plasma driven permeation of hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Takizawa, Masayuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    It is one of the most important problem in PWI of fusion devices from the point of view of tritium leakage that hydrogen diffuses in the wall of the device and permeates through it, which results in hydrogen being released to the coolant side. In this study, plasma driven permeation experiments were carried out with several kinds of metal membranes in the low temperature plasma where ionic and atomic hydrogen as well as electron existed in order to survey PDP mechanism from the many view points. In addition, incident flux rate from the plasma to the membrane surface was evaluated by calculation analysis. As a result the mechanism of low temperature PDP was found out and described as PDP models. The simulation of the membrane pump system was executed and the system performance was estimated with the models. (author). 135 refs.

  1. Study on low temperature plasma driven permeation of hydrogen

    International Nuclear Information System (INIS)

    Takizawa, Masayuki

    1998-03-01

    It is one of the most important problem in PWI of fusion devices from the point of view of tritium leakage that hydrogen diffuses in the wall of the device and permeates through it, which results in hydrogen being released to the coolant side. In this study, plasma driven permeation experiments were carried out with several kinds of metal membranes in the low temperature plasma where ionic and atomic hydrogen as well as electron existed in order to survey PDP mechanism from the many view points. In addition, incident flux rate from the plasma to the membrane surface was evaluated by calculation analysis. As a result the mechanism of low temperature PDP was found out and described as PDP models. The simulation of the membrane pump system was executed and the system performance was estimated with the models. (author). 135 refs

  2. Development of a hydrogen permeation sensor for future tritium applications

    Energy Technology Data Exchange (ETDEWEB)

    Llivina, L.; Colominas, S.; Abellà, J., E-mail: sergi.colominas@iqs.es

    2014-10-15

    Highlights: • Designing and testing of a hydrogen permeation sensor. • Palladium and α-iron have been used as a hydrogen permeation materials in the sensor. • The experiments performed using both membranes showed that the operation of the sensors in the equilibrium mode required at least several hours to reach the hydrogen equilibrium pressure. - Abstract: Tritium monitoring in lithium–lead eutectic is of great importance for the performance of liquid blankets in fusion reactors. In addition, tritium measurements will be required in order to proof tritium self-sufficiency in liquid metal breeding systems. On-line hydrogen (isotopes) sensors must be design and tested in order to accomplish these goals. In this work, an experimental set up was designed in order to test the permeation hydrogen sensors at 500 °C. This experimental set-up allowed working with controlled environments (different hydrogen partial pressures) and the temperature was measured using a thermocouple connected to a temperature controller that regulated an electrical heater. In a first set of experiments, a hydrogen sensor was constructed using an α-iron capsule as an active hydrogen area. The sensor was mounted and tested in the experimental set up. In a second set of experiments the α-iron capsule was replaced by a welded thin palladium disk in order to minimize the death volume. The experiments performed using both membranes (α-iron and palladium) showed that the operation of the sensors in the equilibrium mode required at least several hours to reach the hydrogen equilibrium pressure.

  3. Gas-driven permeation of deuterium through tungsten and tungsten alloys

    Energy Technology Data Exchange (ETDEWEB)

    Buchenauer, Dean A., E-mail: dabuche@sandia.gov [Sandia National Laboratories, Energy Innovation Department, Livermore, CA 94550 (United States); Karnesky, Richard A. [Sandia National Laboratories, Energy Innovation Department, Livermore, CA 94550 (United States); Fang, Zhigang Zak; Ren, Chai [University of Utah, Department of Metallurgical Engineering, Salt Lake City, UT 84112 (United States); Oya, Yasuhisa [Shizuoka University, Graduate School of Science, Shizuoka (Japan); Otsuka, Teppei [Kyushu University, Department of Advanced Energy Engineering Science, Fukuoka (Japan); Yamauchi, Yuji [Hokkaido University, Third Division of Quantum Science and Engineering, Faculty of Engineering, Sapporo (Japan); Whaley, Josh A. [Sandia National Laboratories, Energy Innovation Department, Livermore, CA 94550 (United States)

    2016-11-01

    Highlights: • We have designed and performed initial studies on a high temperature gas-driven permeation cell capable of operating at temperatures up to 1150 °C and at pressures between 0.1–1 atm. • Permeation measurements on ITER grade tungsten compare well with past studies by Frauenfelder and Zahkarov in the temperature range from 500 to 1000 °C. • First permeation measurements on Ti dispersoid-strengthened ultra-fine grained tungsten show higher permeation at 500 °C, but very similar permeation with ITER tungsten at 1000 °C. Diffusion along grain boundaries may be playing a role for this type of material. - Abstract: To address the transport and trapping of hydrogen isotopes, several permeation experiments are being pursued at both Sandia National Laboratories (deuterium gas-driven permeation) and Idaho National Laboratories (tritium gas- and plasma-driven tritium permeation). These experiments are in part a collaboration between the US and Japan to study the performance of tungsten at divertor relevant temperatures (PHENIX). Here we report on the development of a high temperature (≤1150 °C) gas-driven permeation cell and initial measurements of deuterium permeation in several types of tungsten: high purity tungsten foil, ITER-grade tungsten (grains oriented through the membrane), and dispersoid-strengthened ultra-fine grain (UFG) tungsten being developed in the US. Experiments were performed at 500–1000 °C and 0.1–1.0 atm D{sub 2} pressure. Permeation through ITER-grade tungsten was similar to earlier W experiments by Frauenfelder (1968–69) and Zaharakov (1973). Data from the UFG alloy indicates marginally higher permeability (< 10×) at lower temperatures, but the permeability converges to that of the ITER tungsten at 1000 °C. The permeation cell uses only ceramic and graphite materials in the hot zone to reduce the possibility for oxidation of the sample membrane. Sealing pressure is applied externally, thereby allowing for elevation

  4. Hydrogen permeation properties of plasma-sprayed tungsten

    International Nuclear Information System (INIS)

    Anderl, R.A.; Pawelko, R.J.; Hankins, M.R.; Longhurst, G.R.; Neiser, R.A.

    1994-01-01

    Tungsten has been proposed as a plasma-facing component material for advanced fusion facilities. This paper reports on laboratory-scale studies that were done to assess the hydrogen permeation properties of plasma-sprayed tungsten for such applications. The work entailed deuterium permeation measurements for plasma-sprayed (PS) tungsten coatings, sputter-deposited (SP) tungsten coatings, and steel substrate material using a mass-analyzed, 3 keV D + 3 ion beam with fluxes of similar 6.5x10 19 D/m 2 s. Extensive characterization analyses for the plasma-sprayed tungsten coatings were made using Auger spectrometry and scanning electron microscopy (SEM). Observed permeation rates through composite PS-tungsten/steel specimens were several orders of magnitude below the permeation levels observed for SP-tungsten/steel composite specimens and pure steel specimens. Characterization analyses indicated that the plasma-sprayed tungsten coating had a nonhomogeneous microstructure that consisted of splats with columnar solidification, partially-melted particles with grain boundaries, and void regions. Reduced permeation levels can be attributed to the complex microstructure and a substantial surface-connected porosity. ((orig.))

  5. Hydrogen permeation properties of plasma-sprayed tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Anderl, R.A. (Idaho National Engineering Lab., EG and G Idaho Inc., Idaho Falls, ID (United States)); Pawelko, R.J. (Idaho National Engineering Lab., EG and G Idaho Inc., Idaho Falls, ID (United States)); Hankins, M.R. (Idaho National Engineering Lab., EG and G Idaho Inc., Idaho Falls, ID (United States)); Longhurst, G.R. (Idaho National Engineering Lab., EG and G Idaho Inc., Idaho Falls, ID (United States)); Neiser, R.A. (Sandia National Laboratories, Albuquerque, NM 87185 (United States))

    1994-09-01

    Tungsten has been proposed as a plasma-facing component material for advanced fusion facilities. This paper reports on laboratory-scale studies that were done to assess the hydrogen permeation properties of plasma-sprayed tungsten for such applications. The work entailed deuterium permeation measurements for plasma-sprayed (PS) tungsten coatings, sputter-deposited (SP) tungsten coatings, and steel substrate material using a mass-analyzed, 3 keV D[sup +][sub 3] ion beam with fluxes of similar 6.5x10[sup 19] D/m[sup 2] s. Extensive characterization analyses for the plasma-sprayed tungsten coatings were made using Auger spectrometry and scanning electron microscopy (SEM). Observed permeation rates through composite PS-tungsten/steel specimens were several orders of magnitude below the permeation levels observed for SP-tungsten/steel composite specimens and pure steel specimens. Characterization analyses indicated that the plasma-sprayed tungsten coating had a nonhomogeneous microstructure that consisted of splats with columnar solidification, partially-melted particles with grain boundaries, and void regions. Reduced permeation levels can be attributed to the complex microstructure and a substantial surface-connected porosity. ((orig.))

  6. Hydrogen permeation properties of plasma-sprayed tungsten*1

    Science.gov (United States)

    Anderl, R. A.; Pawelko, R. J.; Hankins, M. R.; Longhurst, G. R.; Neiser, R. A.

    1994-09-01

    Tungsten has been proposed as a plasma-facing component material for advanced fusion facilities. This paper reports on laboratory-scale studies that were done to assess the hydrogen permeation properties of plasma-sprayed tungsten for such applications. The work entailed deuterium permeation measurements for plasma-sprayed (PS) tungsten coatings, sputter-deposited (SP) tungsten coatings, and steel substrate material using a mass-analyzed, 3 keV D 3+ ion beam with fluxes of ˜6.5 × 10 19 D/m 2 s. Extensive characterization analyses for the plasma-sprayed tungsten coatings were made using Auger spectrometry and scanning electron microscopy (SEM). Observed permeation rates through composite PS-tungsten/steel specimens were several orders of magnitude below the permeation levels observed for SP-tungsten/steel composite specimens and pure steel specimens. Characterization analyses indicated that the plasma-sprayed tungsten coating had a nonhomogeneous microstructure that consisted of splats with columnar solidification, partially-melted particles with grain boundaries, and void regions. Reduced permeation levels can be attributed to the complex microstructure and a substantial surface-connected porosity.

  7. The formation of hydrogen permeation barriers on steels by aluminising

    Science.gov (United States)

    Forcey, K. S.; Ross, D. K.; Wu, C. H.

    1991-06-01

    An extensive investigation has been carried out into the effectiveness of aluminised layers as permeation barriers on AISI 316L stainless and DIN 1.4914 martensitic steels. The study involved measurement of the hydrogen permeation rate through commercially aluminised steel discs of thicknesses in the range 1-1.6 mm, at temperatures between 250 and 600 °C and for an upstream hydrogen pressure of 10 5 Pa. The composition and structure of the aluminide layers were investigated by a number of techniques such as SEM, electron beam microprobe and X-ray diffraction. Accelerator based techniques such as RBS and NRA were employed to study the top micron or so of the surfaces of the samples. By these techniques it was found that the effectiveness of the permeation barrier depended on the formation of a thin surface oxide layer consisting of Al 2O 3. It was found that the permeation rate through the aluminised steels could be reduced by 3-4 orders of magnitude by forming a surface oxide layer up to a micron or so in thickness.

  8. Influence of bulk and surface phenomena on the hydrogen permeation through metals

    International Nuclear Information System (INIS)

    Waelbroeck, F.; Wienhold, P.; Winter, J.; Rota, E.; Bauno, T.

    1984-12-01

    We discuss the permeation of hydrogen through metals and alloys such as iron, nickel, steels and Inconel wherein H dissolves endothermically from an H 2 gas. We assume first that trapping centers, surface contamination layers, the saturation of the H surface coverage and the implantation profile - when energetic ions drive the permeation - can be neglected, that a quasi-equilibrium exists between the H atom concentration ν in the adsorbed layer and c in the near surface layers and that the H solubility and diffusivity are homogeneous in the membrane. We evaluate thereafter separately the influence of these various effects and identify the parameter domains where appreciable corrections result. The permeation phenomenon is complex even when these simplifications are made: the penetration rate is proportional to the flux of thermal molecules, atoms or energetic ions - depending upon the case - which strike the surface; the diffusion in the metal is proportional to the gradient of c; the release rate depends on c 2 ; the time-dependent diffusion equation includes a double spatial derivative of c. Permeation can only be fully described when computer codes such as PERI is used. Simple analytical relations are however obtained in several limiting cases. They are the object of this report. Some of them had already been derived by other authors but they were not shown to be part of a single, self consistent permeation model. A comparison of predicted and experimental results shows that the simplified model describes surprisingly accurately the hydrogen exchange between gas and metal solutions. (orig./GSCH)

  9. Hydrogen permeation through Flinabe fluoride molten salts for blanket candidates

    Energy Technology Data Exchange (ETDEWEB)

    Nishiumi, Ryosuke, E-mail: r.nishiumi@aees.kyushu-u.ac.jp; Fukada, Satoshi; Nakamura, Akira; Katayama, Kazunari

    2016-11-01

    Highlights: • H{sub 2} diffusivity, solubility and permeability in Flinabe as T breeder are determined. • Effects in composition differences among Flibe, Fnabe and Flinabe are compared. • Changes of pressure dependence of Flinabe permeation rate are clarified. - Abstract: Fluoride molten salt Flibe (2LiF + BeF{sub 2}) is a promising candidate for the liquid blanket of a nuclear fusion reactor, because of its large advantages of tritium breeding ratio and heat-transfer fluid. Since its melting point is higher than other liquid candidates, another new fluoride molten salt Flinabe (LiF + NaF + BeF{sub 2}) is recently focused on because of its lower melting point while holding proper breeding properties. In this experiment, hydrogen permeation behavior through the three molten salts of Flibe (2LiF + BeF{sub 2}), Fnabe (NaF + BeF{sub 2}) and Flinabe are investigated in order to clarify the effects of their compositions on hydrogen transfer properties. After making up any of the three molten salts and purifying it using HF, hydrogen permeability, diffusivity and solubility of the molten salts are determined experimentally by using a system composed of tertiary cylindrical tubes. Close agreement is obtained between experimental data and analytical solutions. H{sub 2} permeability, diffusivity and solubility are correlated as a function of temperature and are compared among the three molten salts.

  10. Hydrogen interactions in aluminum-lithium alloys

    Science.gov (United States)

    Smith, S. W.; Scully, J. R.

    1991-01-01

    A program is described which seeks to develop an understanding of the effects of dissolved and trapped hydrogen on the mechanical properties of selected Al-Li-Cu-X alloys. A proposal is made to distinguish hydrogen (H2) induced EAC from aqueous dissolution controlled EAC, to correlate H2 induced EAC with mobile and trapped concentrations, and to identify significant trap sites and hydride phases (if any) through use of model alloys and phases. A literature review shows three experimental factors which have impeded progress in the area of H2 EAC for this class of alloys. These are as listed: (1) inter-subgranular fracture in Al-Li alloys when tested in the S-T orientation in air or vacuum make it difficult to readily detect H2 induced fracture based on straight forward changes in fractography; (2) the inherently low H2 diffusivity and solubility in Al alloys is further compounded by a native oxide which acts as a H2 permeation barrier; and (3) H2 effects are masked by dissolution assisted processes when mechanical testing is performed in aqueous solutions.

  11. Determination of factor of hydrogen permeation reduction (PRF) for different protective coatings over vanadium

    International Nuclear Information System (INIS)

    Afanasyev, S.; Kulsartov, T.; Shestakov, V.; Chikhray, Y.; Smith, D.

    2002-01-01

    Selection of structural materials for liquid-metal system as well as for another system and constructions of nuclear energy plants must be carried out and based on specified demands depending on conditions of these materials functioning. Specific demand is its compatibility with liquid metals. Design of reactors with liquid-metal coolant (Li, PbLi 17 ) which reproduces tritium arise additional demand to structural materials. This demand is a creation of structural material or protective barrier with minimum acceptable value of tritium permeation through itself or with maximum permeation reduction factor (PRF). Vanadium and vanadium alloys are supposed to be use as a blanket structural material in such nuclear energy plants. Worked out at first stage of studies vanadium coatings should have stability of its characteristics at temperature 800 deg. C under influence of hydrogen. Given work shows the experimental results on testing of protective coatings over vanadium: glass-ceramic coating and CaO-base coating. PRF for every coating and its changes depending on thermo-capacity of vanadium sample with coating was determined by method of hydrogen permeation. The results of experiments would be used at the development of cooling loops of reactor core protection with liquid-metal coolant

  12. Uses and evaluation methods of potential hydrogen permeation barriers for nuclear reactor materials

    International Nuclear Information System (INIS)

    Noga, J.O.; Piercy, G.R.; Bowker, J.T.

    1985-07-01

    This report summarizes results on the use of coatings as hydrogen permeation barriers on nuclear reactor component materials. Two classes of base materials were considered, exothermic hydrogen absorbers and endothermic hydrogen absorbers. The results of the tests indicate that substantial reductions in the amount of hydrogen absorbed by a metal can be achieved through the use of hydrogen permeation barrier coatings. Gold was determined to provide an effective hydrogen permeation barrier on Zr-2-1/2 Nb pressure tube material. Tin was determined to be a suitable hydrogen permeation barrier when applied on AISI 410 stainless steel and iron. Both gas phase and electrochemical permeation techniques were used to determine hydrogen permeabilities through coatings and base materials

  13. Counter-diffusion and -permeation of deuterium and hydrogen through metals

    Energy Technology Data Exchange (ETDEWEB)

    Kizu, Kaname; Tanabe,; Tetsuo, [Nagoya Univ. (Japan)

    1998-03-01

    The first experiments for counter-diffusion and -permeation of deuterium and hydrogen through palladium were performed. Deuterium permeation rates against D{sub 2} pressure were measured under the condition where hydrogen permeated to opposite direction by supplying H{sub 2} gas at the permeated side of D{sub 2}. It was found that not a small amount of deuterium was clearly permeated even if the deuterium pressure was much smaller than the hydrogen pressure. Deuterium permeation rate was gradually reduced by increasing the counter H permeation. The deuterium permeation rate under the counter H permeation is well represented by a simple model in which the ratio of the deuterium permeation rates with and without the counter H permeation was proportional to the fractional concentration of deuterium in the bulk. As increasing the hydrogen counter flow, however, the deuterium permeation rate deviates from the model. This means that adsorption (absorption) of D{sub 2} from gas phase is inhibited and surface recombination of deuterium is blocked by hydrogen. (author)

  14. Hydrogen solubility and permeability of Nb-W-Mo alloy membrane

    International Nuclear Information System (INIS)

    Awakura, Y.; Nambu, T.; Matsumoto, Y.; Yukawa, H.

    2011-01-01

    Research highlights: → The concept for alloy design of Nb-based hydrogen permeable membrane has been applied to Nb-W-Mo ternary alloy in order to improve further the resistance to hydrogen embrittlement and hydrogen permeability. → The alloying effects of Mo on the hydriding properties of Nb-W alloy have been elucidated. → The addition of Mo and/or W into niobium improves the resistance to hydrogen embrittlement by reducing the dissolved hydrogen concentration in the alloy. → Nb-W-Mo alloy possesses excellent hydrogen permeability together with strong resistance to hydrogen embrittlement. - Abstract: The alloying effects of molybdenum on the hydrogen solubility, the resistance to hydrogen embrittlement and the hydrogen permeability are investigated for Nb-W-Mo system. It is found that the hydrogen solubility decreases by the addition of molybdenum into Nb-W alloy. As a result, the resistance to hydrogen embrittlement improves by reducing the hydrogen concentration in the alloy. It is demonstrated that Nb-5 mol%W-5 mol%Mo alloy possesses excellent hydrogen permeability without showing any hydrogen embrittlement when used under appropriate hydrogen permeation conditions, i.e., temperature and hydrogen pressures.

  15. Computational investigation of the effects of barrier layers on the permeation of hydrogen through metals

    International Nuclear Information System (INIS)

    Perkins, W.G.

    1975-01-01

    Results of a computational investigation of the permeation behavior of oxide-coated metal membranes are presented. A steady-state permeation model was developed which promises to be useful in evaluation of oxide layers on metals as hydrogen permeation barriers. The pressure and thickness dependence of steady state permeation through oxide-coated metal membranes is described using plots of logarithmic functions. (U.S.)

  16. Examination of several pre-oxidation procedures and their effect as hydrogen permeation-barrier

    International Nuclear Information System (INIS)

    Heimes, E.

    1986-03-01

    Several pre-oxidation procedures have been tested with respect to their effect as a hydrogen permeation barrier at the high temperature alloys Hastelloy X and Inconel 617. By outside coating of Hastelloy X samples with alumina the determined impeding effects were very low. A surface aluminium enrichment by different procedures were accomplished before selective oxidation. The method of Aluminium-Hot-Dipping generated oxide layers with a four- to fivefold higher impeding effect compared to specimens fabricated by a standard procedure. With the aid of a metallographical follow-up examination it was shown that the higher impeding effects are due to an improved adhesion between the oxide layer and the high temperature material, whereby in the cooling period after manufacturing a smaller amount of oxide cracking is obtainable. (orig./PW) [de

  17. Influence of adsorbed hydrogen molecules on the hydrogen permeation and recycling

    International Nuclear Information System (INIS)

    Banno, T.

    1987-01-01

    Hydrogen permeation through a thin iron membrane has been measured using a molecular hydrogen gas and/or a weakly ionized rf-discharge as particle sources. Transient and steady state values of the permeation flux φ p were obtained in the regime where the surface penetration of H and the recombinative release of H 2 are rate-determining. φ p is then proportional to the flux density ψ of the particles which impinge on the membrane upstream. The proportionality factors depend on the nature (atomic or molecular) of the incident particles, on temperature (in particular for a molecular driving gas) and on the ratio of the surface recombinative release rate constants (2σk r ) u and (2σk r ) d up- and downstream, respectively. (orig.)

  18. Palladium alloys for hydrogen diffusion

    International Nuclear Information System (INIS)

    1977-01-01

    A palladium-base alloy with tin and/or a silicon addition and its use in the production of hydrogen from water via a cycle of chemical reactions, of which the decomposition of HI into H 2 and I 2 is the most important, is described

  19. Hydrogen permeation modification of 4140 steel by ion nitriding with pulsed plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Bruzzoni, P.; Ortiz, M. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Bruehl, S.P.; Gomez, B.J.A.; Feugeas, J.N. [Inst. de Fisica Rosario (UNR-CONICET), Rosario (Argentina); Nosei, L. [Inst. de Mecanica Aplicada y Estructuras (UNR), Rosario (Argentina)

    1998-11-10

    It is widely known that the hydrogen in steel produces embrittlement. This effect may cause the failure of the elements (confining walls, mechanical parts, etc.) whose surfaces are in contact with this gas or with processes in which hydrogen is continuously generated. In this work it is shown that the ion nitriding of the surface of AISI 4140 is a good mechanism to act as a barrier against hydrogen permeation in its bulk. The ion nitriding was performed using a square wave DC glow discharge. The development of a compound layer of iron nitrides was observed as the cause of the hydrogen permeation reduction. For equal duration of treatment, thicker compound layers were developed in higher discharge/post-discharge ratios in the square wave of the applied voltage onto the sample (cathode), with a greater reduction of hydrogen permeation coefficient as a consequence. Nevertheless, the permeation was not reduced to zero in any of the treatment conditions used. The results of the analysis of the permeation tests and the image of the photomicrographs showed that the existence of cracks, fractures, failures, etc. in the compound layer (pre-existing in the AISI 4140 steel) could be the cause of the residual hydrogen permeation. This can be attributed to the movement of the hydrogen through these defects diffusing through the original {alpha}-Fe phase of the non-treated steel. (orig.) 11 refs.

  20. Changes on iron electrode surface during hydrogen permeation in borate buffer solution

    International Nuclear Information System (INIS)

    Modiano, S.; Carreno, J.A.V.; Fugivara, C.S.; Torresi, R.M.; Vivier, V.; Benedetti, A.V.; Mattos, O.R.

    2008-01-01

    Hydrogen interaction with oxide films grown on iron electrodes at open circuit potential (E oc ) and in the passive region (+0.30 V ECS ) was studied by chronopotentiometry, chronoamperometry and electrochemical impedance spectroscopy techniques. The results were obtained in deaerated 0.3 mol L -1 H 3 BO 3 + 0.075 mol L -1 Na 2 B 4 O 7 (BB, pH 8.4) solution before, during and after hydrogen permeation. The iron oxide film modification was also investigated by means of in situ X-ray absorption near-edge spectroscopy (XANES) and scanning electrochemical microscopy (SECM) before and during hydrogen permeation. The main conclusion was that the passive film is reduced during the hydrogen diffusion. The hydrogen permeation stabilizes the iron surface at a potential close to the thermodynamic water stability line where hydrogen evolution can occur. The stationary condition required for the determination of the permeation parameters cannot be easily attained on iron surface during hydrogen permeation. Moreover, additional attention must be paid when obtaining the transport parameters using the classical permeation cell

  1. Determination of trapping parameters and the chemical diffusion coefficient from hydrogen permeation experiments

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Jiří; Mori, G.; Prethaler, A.; Fischer, F. D.

    2014-01-01

    Roč. 82, MAY (2014), s. 93-100 ISSN 0010-938X Institutional support: RVO:68081723 Keywords : Steel * Electrochemical calculation * Modeling studies * Hydrogen permeation * Kinetic parameters Subject RIV: BJ - Thermodynamics Impact factor: 4.422, year: 2014

  2. Interaction of hydrogen with Pb83Li17 eutectic alloy

    International Nuclear Information System (INIS)

    Kumar, Sanjay; Taxak, Manju; Krishnamurthy, N.

    2011-01-01

    Liquid Metal blankets are attractive candidates for both near-term and long-term fusion applications. Lead-lithium alloy appears to be promising for the use in self cooled breeding blanket, which has inherent simplicity with candidate material liquid lithium serving as both breeder and coolant. The crucial issues in case of lead lithium are the permeation loss of tritium (T) to the coolant and surroundings and the formation of new phase LiH/LiT, which eventually change the physical properties. Present investigation is based on the interaction process of hydrogen with the alloy and the relevant changes in physical properties. (author)

  3. Current Design of the Flange Type Hydrogen Permeation Sensor in Liquid Breeder

    International Nuclear Information System (INIS)

    Lee, E. H.; Jin, H. G.; Yoon, J. S.; Kim, S. K.; Lee, D. W.; Lee, H. G.

    2015-01-01

    In 2004, A. Ciampichetti et al. proposed a hollow capsule shape permeation sensor and they theoretically and experimentally evaluated the performance of the sensor made of Nb membrane at test condition of 500 .deg. C. However, the evaluation result showed the measured hydrogen permeation flux in the sensor much lower than the predicted one and they concluded that, the result is due to the formation of an oxide layer on the sensor membrane surface. Three years later, A. Ciampichetti et al. observed that a hollow capsule shape permeation sensor has too long response time to measure hydrogen concentration in liquid breeder. However, they suggested optimizing the sensor geometry with the reduction of the ratio 'total sensor volume/permeation surface' to overcome the low hydrogen permeating flux. For development of the liquid breeding technologies in nuclear fusion, the permeation sensor to measure tritium concentration in liquid metal breeder has been developed. Lee et al. proposed a flange type permeation sensor to dramatically reduce the ratio sensor 'inside volume/permeation surface' and to remove membrane welding during sensor manufacture process. However, the flange type sensor has problem with sealing. In present study, the modified flange sensor design with a metallic C-ring spring gasket is introduced. The modified sensor will be verified and evaluated under high temperature conditions by end of 2015

  4. Current Design of the Flange Type Hydrogen Permeation Sensor in Liquid Breeder

    Energy Technology Data Exchange (ETDEWEB)

    Lee, E. H.; Jin, H. G.; Yoon, J. S.; Kim, S. K.; Lee, D. W. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, H. G. [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    In 2004, A. Ciampichetti et al. proposed a hollow capsule shape permeation sensor and they theoretically and experimentally evaluated the performance of the sensor made of Nb membrane at test condition of 500 .deg. C. However, the evaluation result showed the measured hydrogen permeation flux in the sensor much lower than the predicted one and they concluded that, the result is due to the formation of an oxide layer on the sensor membrane surface. Three years later, A. Ciampichetti et al. observed that a hollow capsule shape permeation sensor has too long response time to measure hydrogen concentration in liquid breeder. However, they suggested optimizing the sensor geometry with the reduction of the ratio 'total sensor volume/permeation surface' to overcome the low hydrogen permeating flux. For development of the liquid breeding technologies in nuclear fusion, the permeation sensor to measure tritium concentration in liquid metal breeder has been developed. Lee et al. proposed a flange type permeation sensor to dramatically reduce the ratio sensor 'inside volume/permeation surface' and to remove membrane welding during sensor manufacture process. However, the flange type sensor has problem with sealing. In present study, the modified flange sensor design with a metallic C-ring spring gasket is introduced. The modified sensor will be verified and evaluated under high temperature conditions by end of 2015.

  5. Nitride and carbide thin films as hydrogen permeation barrier on Manet steel

    International Nuclear Information System (INIS)

    Benamati, G.; Checchetto, R.; Bonelli, M.; Gratton, L.M.; Guzman, L.; Miotello, A.; Terlain, A.

    1995-01-01

    TiC / TiN bilayers, ∼ 1.2 μm thick, were deposited on Manet II steel by the ion beam assisted deposition technique to investigate the possible use of this ceramic coating as hydrogen barrier. Hydrogen permeation experiments in the temperature range 470-570 K showed indeed that this coating is a very efficient barrier to the hydrogen permeation being able to reduce the hydrogen flux up to two order of magnitude with respect to the uncoated steel. Preliminary compatibility tests between coated Manet II and Pb-17Li showed no attack of Pb-17Li to the steel. (orig.)

  6. Nitride and carbide thin films as hydrogen permeation barrier on MANET steel

    International Nuclear Information System (INIS)

    Benamati, G.

    1994-01-01

    TiC/TiN bilayers, - 1.2 μm thick, were deposited on Manet II steel by the ion beam assisted deposition technique to investigate the possible use of this ceramic coating as hydrogen barrier. Hydrogen permeation experiments in the temperature range 470-570 K showed indeed that this coating is a very efficient barrier to the hydrogen permeation being able to reduce the hydrogen flux up to two order of magnitude with respect to the uncoated steel. Preliminary compatibility tests between coated Manet II and Pb-17Li showed no attack of Pb-17Li to the steel. (author) 8 refs.; 2 figs.; 1 tab

  7. Modell experiments to determine the effect of inhibitive oxide layers on metals against hydrogen permeation

    International Nuclear Information System (INIS)

    Zink, U.

    1983-11-01

    The coupling of H 2 -permeation and corrosion has been examined with the high-temperature alloys Incoloy 800 and Incoloy 802. Permeationsrates as well as corrosionsrates have been measured simultanously under H 2 O-H 2 atmospheres in the test-facility HD-PERM. Test parameters have been temperature and oxidationpotential. Parabolic laws for the growth of the oxide scales have been identified and are considered to be highly important for the efficiency of a permeation barrier. A comparison between the temperature dependencies of corrosionsrates and H 2 -permeationsrates has revealed that permeation and corrosion are coupled only in so far that the permeation barrier is formed by the corrosion reaction. The corrosion data (parabolic rate constant, activation energy) of the oxide scales have given clear indications for the existence of a Cr 2 O 3 -layer, which is considered to be responsible for efficient oxide permeation barriers. (orig.) [de

  8. Hydrogen permeation through sol-gel-coated iron during galvanostatic charging

    International Nuclear Information System (INIS)

    Zakorchemna, I.; Carmona, N.; Zakroczymski, T.

    2008-01-01

    One-layer sol-gel silica-zirconia and two-layer silica-zirconia and zirconia coatings were deposited on one side of iron membranes by spin-coating, densified in air and annealed up to 800 deg. C in vacuum. Hydrogen permeation through the membranes, coated and uncoated, polarised cathodically under galvanostatic control in 0.1 M NaOH solution was studied using the electrochemical permeation technique. During the initial period, the effect of the sol-gel coatings was insignificant. However, the coatings quite efficiently prevented the iron surface become more active to hydrogen entry during a long-lasting cathodic polarisation. In addition, the electrochemical-corrosion behaviour of the coated iron and the effect of the sol-gel coatings on the effective diffusivity of hydrogen in the coated membranes were studied. On the basis of the polarisation curves and the hydrogen permeation data it was proved that the sol-gel coatings blocked the iron surface for the hydrogen evolution reaction and, consequently, for the hydrogen entry into iron. The effective coating coverage was determined by comparison of the hydrogen fluxes permeating the coated and uncoated membranes. Finally the real concentration of hydrogen beneath the uncoated iron sites and the amount of hydrogen stored in a membrane were evaluated

  9. Introduction to hydrogen in alloys

    International Nuclear Information System (INIS)

    Westlake, D.G.

    1980-01-01

    Substitutional alloys, both those that form hydrides and those that do not, are discussed, but with more emphasis on the former than the latter. This overview includes the following closely related subjects: (1) the significant effects of substitutional solutes on the pressure-composition-temperature (PCT) equilibria of metal-hydrogen systems, (2) the changes in thermodynamic properties resulting from differences in atom size and from modifications of electronic structure, (3) attractive and repulsive interactions between H and solute atoms and the effects of such interactions on the pressure dependent solubility for H, (4) H trapping in alloys of Group V metals and its effect on the terminal solubility for H (TSH), (5) some other mechanisms invoked to explain the enhancement (due to alloying) of the (TSH) in Group V metals, and (6) H-impurity complexes in alloys of the metals Ni, Co, and Fe. Some results showing that an enhanced TSH may ameliorate the resistance of a metal to hydrogen embrittlement are presented

  10. Influence of nitrogen ion implantation on hydrogen permeation in an extra mild steel

    International Nuclear Information System (INIS)

    Brass, A.M.; Chene, J.; Pivin, J.C.

    1989-01-01

    This paper presents the first results on the effect of nitrogen implantation on hydrogen permeation in steels. Nitrogen can modify superficially the steel's chemistry and/or microstructure depending on the fluence and thereby affect the processes of hydrogen diffusion and trapping. The implantations were performed on low carbon steel specimens with different nominal doses (1% to 10% and 33% nitrogen in a superficial layer of approximately 100 to 120 nm). The corresponding microstructures were characterized and permeation tests were conducted at room temperature in a double electrolytic cell. The nitrogen implanted layers on iron affects the electrochemical behaviour of the surface and the permeation in the material. This effect depends on the nitrogen concentration in the layer and on the corresponding microstructure. A continuous Fe 2 N layer acts as an efficient barrier to hydrogen entry and permeation when the layer is located on the entry face of the permeation membrane. This effect is stronger when the implanted layer is on the downstream face of the membrane. The low permeability values are mainly attributed to a lower hydrogen solubility in the implanted layer, whereas hydrogen trapping on defects and nitride precipitates delay hydrogen penetration. (author)

  11. Hydrogen ion-driven permeation in carbonaceous films

    International Nuclear Information System (INIS)

    Anderl, R.A.; Holland, D.F.; Longhurst, G.R.

    1989-01-01

    This paper presents the results of investigations into the permeation properties of amorphous carbonaceous, a-C:H, films produced by plasmachemical deposition techniques. Carbonaceous films on iron substrates with thickness ranging from 60 nm to 110 nm were subjected to high fluence implantations with mass analyzed D 3 + ions with energies ranging from 600 eV to 3000 eV and fluxes ranging from 5x10 14 D/cm 2 s to 5x10 15 D/cm 2 s, respectively. Deuterium re-emission upstream, deuterium permeation downstream and secondary ions sputtered from the implantation surface were measured as a function of implantation fluence for specimens at 420 K. The present studies indicate that the a-C:H film permeability is directly related to the time, hence the fluence, required to achieve isotopic replacement and saturation of the deuterium ion beam atoms stopped in the implant region. Once the deuterium saturation level is achieved in the layer, a significant fraction of the implanting ions can result in permeation. For the present experiment, this permeation factor was much higher than that for uncoated iron specimens subjected to similar beam conditions. Carbon sputter yields of 0.008-0.01 C/D were determined in this work for 1000-eV to 400-eV deuterium ions incident on a-C:H films. (orig.)

  12. Hydrogen ion-driven permeation in carbonaceous films

    Energy Technology Data Exchange (ETDEWEB)

    Anderl, R.A.; Holland, D.F.; Longhurst, G.R.

    1989-04-01

    This paper presents the results of investigations into the permeation properties of amorphous carbonaceous, a-C:H, films produced by plasmachemical deposition techniques. Carbonaceous films on iron substrates with thickness ranging from 60 nm to 110 nm were subjected to high fluence implantations with mass analyzed D/sub 3//sup +/ ions with energies ranging from 600 eV to 3000 eV and fluxes ranging from 5x10/sup 14/ D/cm/sup 2/ s to 5x10/sup 15/ D/cm/sup 2/ s, respectively. Deuterium re-emission upstream, deuterium permeation downstream and secondary ions sputtered from the implantation surface were measured as a function of implantation fluence for specimens at 420 K. The present studies indicate that the a-C:H film permeability is directly related to the time, hence the fluence, required to achieve isotopic replacement and saturation of the deuterium ion beam atoms stopped in the implant region. Once the deuterium saturation level is achieved in the layer, a significant fraction of the implanting ions can result in permeation. For the present experiment, this permeation factor was much higher than that for uncoated iron specimens subjected to similar beam conditions. Carbon sputter yields of 0.008-0.01 C/D were determined in this work for 1000-eV to 400-eV deuterium ions incident on a-C:H films. (orig.).

  13. Hydrogen ion-driven permeation in carbonaceous films

    Science.gov (United States)

    Anderl, R. A.; Holland, D. F.; Longhurst, G. R.

    1989-04-01

    This paper presents the results of investigations into the permeation properties of amorphous carbonaceous, a-C: H, films produced by plasmachemical deposition techniques. Carbonaceous films on iron substrates with thickness ranging from 60 nm to 110 nm were subjected to high fluence implantations with mass analyzed D +3 ions with energies ranging from 600 eV to 3000 eV and fluxes ranging from 5 × 10 14D/ cm2 s to 5 × 10 15D/ cm2 s, respectively. Deuterium re-emission upstream, deuterium permeation downstream and secondary ions sputtered from the implantation surface were measured as a function of implantation fluence for specimens at 420 K. The present studies indicate that the a-C : H film permeability is directly related to the time, hence the fluence, required to achieve isotopic replacement and saturation of the deuterium ion beam atoms stopped in the implant region. Once the deuterium saturation level is achieved in the layer, a significant fraction of the implanting ions can result in permeation. For the present experiment, this permeation factor was much higher than that for uncoated iron specimens subjected to similar beam conditions. Carbon sputter yields of 0.008-0.01 C/D were determined in this work for 1000-eV to 400-eV deuterium ions incident on a-C : H films.

  14. STRUCTURAL INTERACTIONS OF HYDROGEN WITH BULK AMORPHOUS MICROSTRUCTURES IN METALLIC SYSTEMS UNDERSTANDING THE ROLE OF PARTIAL CRYSTALLINITY ON PERMEATION AND EMBRITTLEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Brinkman, Kyle; Fox, Elise; Korinko, Paul; Adams, Thad

    2010-05-10

    The development of metallic glasses in bulk form has led to a resurgence of interest into the utilization of these materials for a variety of applications. A potentially exciting application for these bulk metallic glass (BMG) materials is their use as composite membranes to replace high cost Pd/Pd-alloy membranes for enhanced gas separation processes. One of the major drawbacks to the industrial use of Pd/Pd-alloy membranes is that during cycling above and below a critical temperature an irreversible change takes place in the palladium lattice structure which can result in significant damage to the membrane. Furthermore, the cost associated with Pd-based membranes is a potential detractor for their continued use and BMG alloys offer a potentially attractive alternative. Several BMG alloys have been shown to possess high permeation rates, comparable to those measured for pure Pd metal. In addition, high strength and toughness when either in-situ or ex-situ second phase dispersoids are present. Both of these properties, high permeation and high strength/toughness, potentially make these materials attractive for gas separation membranes that could resist hydrogen 'embrittlement'. However, a fundamental understanding of the relationship between partially crystalline 'structure'/devitrification and permeation/embrittlement in these BMG materials is required in order to determine the operating window for separation membranes and provide additional input to the material synthesis community for improved alloy design. This project aims to fill the knowledge gap regarding the impact of crystallization on the permeation properties of metallic glass materials. The objectives of this study are to (i) determine the crystallization behavior in different gas environments of Fe and Zr based commercially available bulk metallic glass and (ii) quantify the effects of partial crystallinity on the hydrogen permeation properties of these metallic glass membranes.

  15. RF plasma-driven hydrogen permeation through a biased iron membrane

    International Nuclear Information System (INIS)

    Banno, T.; Waelbroeck, F.; Winter, J.

    1984-01-01

    The steady-state RF plasma-driven hydrogen permeation through an electrically biased iron membrane has been investigated as a function of the bias potential Vsub(M) for membrane temperatures in the range of 150-400 0 C. Vsub(M) has been gradually increased positively from the floating potential of the membrane. The permeation flux decreases when Vsub(M) increases at low voltages: positive hydrogen ions are repelled. The membrane temperature does not influence this effect measurably. The permeation flux starts to increase when Vsub(M) is raised higher, i.e. when energetic electrons strike the surface. This phenomenon shows a pronounced temperature dependence - the enhancement is largest for the lowest temperatures. The effect is interpreted in terms of an electron-induced dissociation of hydrogen molecules on the membrane surface. (orig.)

  16. Effect of argon ion sputtering of surface on hydrogen permeation through vanadium

    International Nuclear Information System (INIS)

    Yamawaki, Michio; Namba, Takashi; Yoneoka, Toshiaki; Kanno, Masayoshi; Shida, Koji.

    1983-01-01

    In order to measure the hydrogen permeation rate through V with atomically cleaned surface, an Ar ion sputtering apparatus has been installed in the hydrogen permeability measuring system. The permeation rate of the initial specimen was found to be increased by about one order of magnitude after Ar ion sputtering of its upstream side surface. Repeating of such a sputter-cleaning was not so much effective in increasing the steady state permeation rate as the initial sputtering was, but it accelerated the transient response rate by a factor of 2 or 3. The transient response rate was also accelerated by the increase of hydrogen pressure, but this effect tended to be diminished by the sputter-cleaning of specimen surface. The surface impurity layer on the downstream side of specimen was also inferred to act as a diffusion barrier affecting the steady state permeation rate. The present value of activation energy for hydrogen permeation through V at temperatures below 873K was the smallest one ever obtained, showing that the surface effect was minimized in the present study on account of the surface sputter-cleaning in addition to the ultra high vacuum system. (author)

  17. Iron titanium manganase alloy hydrogen storage

    Science.gov (United States)

    Reilly, James J.; Wiswall, Jr., Richard H.

    1979-01-01

    A three component alloy capable of reversible sorption of hydrogen having the chemical formula TiFe.sub.1-x Mn.sub.x where x is in the range of about 0.02 to 0.5 and the method of storing hydrogen using said alloy.

  18. Effects of thin films on inventory, permeation and re-emission of energetic hydrogen

    International Nuclear Information System (INIS)

    Ohyabu, N.; Nakamura, Y.; Nakahara, Y.; Livshits, A.; Alimov, V.; Busnyuk, A.; Notkin, M.; Samartsev, A.; Doroshin, A.

    2000-01-01

    A non-metallic coating thicker than the implantation depth may protect a metal against tritium retention and permeation. However, a thinner film has quite the opposite effect: a dramatic increase of permeation and retention, and a corresponding suppression of re-emission. In view of the benefits expected from particle control with a superpermeable membrane placed right inside the divertor, the behavior of a Nb sample was investigated in a plasma-membrane device having a graphite target. Even polyatomic carbide coating was found not to hinder hydrogen absorption and permeation. Polyatomic non-carbide C films effectively inhibits it, but the formation of such films depends on H and C fluxes, H energy and metal temperature. A durable isolation of suprathermal hydrogen with the superpermeable membrane was observed at a high enough ratio between H and C fluxes, and the effects of carbon were found to have a non-monotonic temperature dependence

  19. The permeation of hydrogen in a steel at elevated temperature by an electrochemical method

    International Nuclear Information System (INIS)

    Tsubakino, H.; Ando, A.; Yamakawa, K.

    1984-01-01

    An electrochemical permeation method has been widely used to study the transport characteristics of hydrogen in metals, i.e., the content, diffusivity and permeability. This electrochemical measurement technique has the following remarkable features: a good detection limit for the measurement of hydrogen content, a simpler measuring apparatus, suitability for successive measurement of the transport characteristics, and flexibility in variation of experimental conditions. However this method has been restricted to temperatures below 373 K because an aqueous solution has been used as an electrode. In this study, an electrochemical permeation method using molten salts at elevated temperatures (673-773 K) in the range of practical interest for hydrogen attack in steel is presented. The introduction of hydrogen by use of molten salts has been reported but it has been performed at 423473 K and at 553 K

  20. Electrochemical permeation tests on the kinetics of the hydrogen absorption of palladium and iron

    International Nuclear Information System (INIS)

    Dafft, E.G.

    1977-01-01

    Electrochemical permeation tests were performed to investigate the kinetics of the hydrogen development and hydrogen absorption. The cathode side of the samples was galvanostatically cathodically polarized in different electrolyte solutions with and without additions. THe hydrogen atoms diffusing out of the opposite side for iron and α-palladium were oxidized with potentiostatic, sufficiently anodic polarization. The thus registered stationary current is proportional to the hydrogen activity on the cathode side. Test apparatus and conditions are described. The measurements on iron are discussed. (orig./HPOE) [de

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

    International Nuclear Information System (INIS)

    Haberman, J.H.; Frydrych, D.J.; Westerman, R.E.

    1988-03-01

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

  2. Permeation of hydrogen at low pressures through stainless steel and implications for tritium control in fusion reactor systems

    International Nuclear Information System (INIS)

    Axtmann, R.C.; Johnson, E.F.; Kuehler, C.W.

    1976-01-01

    New experimental data on the permeation of hydrogen through stainless steel indicate that at driving pressures below 10 -2 torr, the permeation rate is linearly dependent on the driving pressure. A possible consequence is that the permeation rates of hydrogenic species in fusion reactor systems might be much lower than those reported in contemporary conceptual design studies which assume that the rates are dependent on the square root of the driving pressure. The important implications of these low permeation rates are: (1) tritium losses to the environment may be more dependent on ordinary leaks from equipment than on permeation to the steam cycle; (2) recovery of tritium from breeding blankets via permeation windows may be impracticable; and (3) recovery of tritium from breeding blankets not dependent on permeation windows may be simplified by the possibility of operating at much higher average tritium concentrations in the blanket and cooling systems

  3. Hydrogen permeation on Al{sub 2}O{sub 3}-based nickel/cobalt composite membranes

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jihee; Jung, Miewon [Department of Chemistry/Institute of Basic Science, Sungshin Women' s University, Seoul 136-742 (Korea, Republic of); Hong, Tae-Whan [Department of Materials Science and Engineering/Research Center for Sustainable Eco-Devices and Materials(ReSEM), Chungju National University, Chungju 380-702 (Korea, Republic of)

    2010-12-15

    Al{sub 2}O{sub 3} was synthesized using the sol-gel process with aluminum isopropoxide as the precursor and primary distilled water as the solvent. Nickel and cobalt metal powders were used to increase the strength of the membranes. The Al{sub 2}O{sub 3}-based membranes were prepared using HPS following a mechanical alloying process. The phase transformation, thermal evolution, surface and cross-section morphology of Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-based membranes were characterized by XRD, TG-DTA and FE-SEM. The hydrogen permeation of Al{sub 2}O{sub 3}-based membranes was examined at 300-473 K under increasing pressure. Hydrogen permeation flux through an Al{sub 2}O{sub 3}-20wt%Co membrane was obtained to 2.36 mol m{sup -2} s{sup -1}. Reaction enthalpy was calculated to 4.5 kJ/mol using a Van't Hoff's plot. (author)

  4. Magnesium mechanical alloys for hydrogen storage

    International Nuclear Information System (INIS)

    Ivanov, E.; Konstanchuk, I.; Stepanov, A.; Boldyrev, V.

    1985-01-01

    Metal hybrides are currently being used to store and handle hydrogen and its isotopes. They are also being tested in hydrogen compressors and in heat energy, refrigerators and in hydrogen and thermal storage devices. Metal hydrides have been proposed as one of the possible media for hydrogen storage to overcome the limitations of other techniques in regard to safety hydrogen weight and volume ration. The suitability of metal hybrides as a hydrogen storage media depends on a number of factors such as storage capacity, reactivity with hydrogen at various pressures and temperatures, and the cost of base materials. Magnesium based alloys are promising materials for storing hydrogen. They are generally made by argon melting and no attention has been payed to other fabrication techniques such as mechanical alloying or powder technique

  5. Research on Crack-Filling Heat Treatment and Hydrogen Permeation Test of Self-healing Tritium Permeation Barriers

    Science.gov (United States)

    Liu, Dawei; Wang, Yan; Zhang, Ying; Ouyang, Taoyuan; Zhou, Tong; Fang, Xuanwei; Suo, Jinping

    2018-03-01

    A TiC + mixture (TiC/Al2O3 (1:1 wt.%)) +Al2O3 self-healing triple layer coating (TLC) was designed and manufactured by our group, and the crack-filling heat treatment process had been roughly explored in the past. In this work, the accelerating test with a thick TiC + mixture (TiC/Al2O3 (1:1 wt.%)) double-layer coating (DLC) was carried out. The DLC coating warped when the heat treatment temperature was lower than 550 °C, which was rare in similar researches, and it crushed into fan-shaped pieces when the treatment temperature was higher than 650 °C. The two different spalling failures were explained by weight gain, porosity and stress analyses. The heating rate had a significant effect. The bonding strength and hydrogen permeation of the TLC samples were also tested. Remaining at 650 °C for 40 h was proved to be an optimal crack-filling heat treatment process, considering the hydrogen resistance.

  6. Effects of impurities on hydrogen permeability through palladium alloy membrane at comparatively high pressure and temperature

    International Nuclear Information System (INIS)

    Yoshida, Hiroshi; Konishi, Satoshi; Katsuta, Hiroji; Naruse, Yuji

    1982-02-01

    Palladium alloy membrane method is considered to be a useful technique for fusion reactor fuel purification process. To study the feasibility of this method, the effects of impurities on permeation characteristics of palladium alloy membrane were examined. Experiments were carried out at practical conditions: pressure; 120 - 1200 kPa, temperature; about 700 K. No poisoning effect on hydrogen permeability of commercial Pd-Ag (Au.Ru) alloy was observed for impurities such as NH 3 , CH 4 , CO, CO 2 , O 2 and N 2 , which were mixed with hyper-pure H 2 at low concentration level (10 - 10000 ppm). Deterioration occurred by contamination with oil vapor. However, regeneration of the membrane was easily performed by air baking followed by hydrogen reduction. Chemical reactions in the permeation cell were also examined. (author)

  7. [Applications of self-renewing coatings to improved vacuum materials, hydrogen permeation barriers and sputter-resistant materials

    International Nuclear Information System (INIS)

    1985-01-01

    The phenomena of Gibbsian segregation, radiation-induced segregation and radiation-induced precipitation modify the surface composition and properties of alloys and compounds. In some cases, the change in properties is both substantial and useful, the most notable example being that of stainless steel. When surface-modifying phenomena are investigated as a class, a number of additional materials emerge as candidates for study, having potential applications in a number of technologically important areas. These materials are predicted to produce self-sustaining coatings which provide hydrogen permeation barriers, low-sticking and stimulated desorption coefficients for vacuum applications, and low-Z, sputtering-resistant surfaces for fusion applications. Several examples of each type of material are presented, along with a discussion of the experimental verification of their properties and the status of the corresponding applications development program

  8. Positron annihilation study of hydrogen storage alloys

    International Nuclear Information System (INIS)

    Shirai, Yasuharu; Araki, Hideki; Sakaki, Kouji

    2003-01-01

    Some AB 5 and AB 2 hydrogen storage alloys have been characterized by using positron-annihilation lifetime spectroscopy. It has been shown that they contain no constitutional vacancies and that deviations from the stoichiometric compositions are all compensated by antistructure atoms. Positron lifetimes in fully-annealed LaNi 5-x Al x and MmNi 5-x Al x alloys show good correlation with their hydrogen desorption pressures. On the other hand, surprising amounts of vacancies together with dislocations have been found to be generated during the first hydrogen absorption process of LaNi 5 and ZrMn 2 . These lattice defects play important role in hydrogen absorption-desorption processes of hydrogen storage alloys. (author)

  9. THE IMPACT OF PARTIAL CRYSTALLIZATION ON THE PERMEATION PROPERTIES BULK AMORPHOUS GLASS HYDROGEN SEPARATION MEMBRANES

    Energy Technology Data Exchange (ETDEWEB)

    Brinkman, K; Paul Korinko, P; Thad Adams, T; Elise Fox, E; Arthur Jurgensen, A

    2008-11-25

    It is recognized that hydrogen separation membranes are a key component of the emerging hydrogen economy. A potentially exciting material for membrane separations are bulk metallic glass materials due to their low cost, high elastic toughness and resistance to hydrogen 'embrittlement' as compared to crystalline Pd-based membrane systems. However, at elevated temperatures and extended operation times structural changes including partial crystallinity may appear in these amorphous metallic systems. A systematic evaluation of the impact of partial crystallinity/devitrification on the diffusion and solubility behavior in multi-component Metallic Glass materials would provide great insight into the potential of these materials for hydrogen applications. This study will report on the development of time and temperature crystallization mapping and their use for interpretation of 'in-situ' hydrogen permeation at elevated temperatures.

  10. Amorphous Alloy Membranes Prepared by Melt-Spin methods for Long-Term use in Hydrogen Separation Applications

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, Dhanesh; Kim, Sang-Mun; Adibhatla, Anasuya; Dolan, Michael; Paglieri, Steve; Flanagan, Ted; Chien, Wen-Ming; Talekar, Anjali; Wermer, Joseph

    2013-02-28

    Amorphous Ni-based alloy membranes show great promise as inexpensive, hydrogenselective membrane materials. In this study, we developed membranes based on nonprecious Ni-Nb-Zr alloys by adjusting the alloying content and using additives. Several studies on crystallization of the amorphous ribbons, in-situ x-ray diffraction, SEM and TEM, hydrogen permeation, hydrogen solubility, hydrogen deuterium exchange, and electrochemical studies were conducted. An important part of the study was to completely eliminate Palladium coatings of the NiNbZr alloys by hydrogen heattreatment. The amorphous alloy (Ni0.6Nb0.4)80Zr20 membrane appears to be the best with high hydrogen permeability and good thermal stability.

  11. Capacity retention in hydrogen storage alloys

    Science.gov (United States)

    Anani, A.; Visintin, A.; Srinivasan, S.; Appleby, A. J.; Reilly, J. J.; Johnson, J. R.

    1992-01-01

    Results of our examination of the properties of several candidate materials for hydrogen storage electrodes and their relation to the decrease in H-storage capacity upon open-circuit storage over time are reported. In some of the alloy samples examined to date, only about 10 percent of the hydrogen capacity was lost upon storage for 20 days, while in others, this number was as high as 30 percent for the same period of time. This loss in capacity is attributed to two separate mechanisms: (1) hydrogen desorbed from the electrode due to pressure differences between the cell and the electrode sample; and (2) chemical and/or electrochemical degradation of the alloy electrode upon exposure to the cell environment. The former process is a direct consequence of the equilibrium dissociation pressure of the hydride alloy phase and the partial pressure of hydrogen in the hydride phase in equilibrium with that in the electrolyte environment, while the latter is related to the stability of the alloy phase in the cell environment. Comparison of the equilibrium gas-phase dissociation pressures of these alloys indicate that reversible loss of hydrogen capacity is higher in alloys with P(eqm) greater than 1 atm than in those with P(eqm) less than 1 atm.

  12. Hydrogen permeation measurement of the reduced activation ferritic steel F82H by the vacuum thermo-balance method

    International Nuclear Information System (INIS)

    Yoshida, Hajime; Enoeda, Mikio; Abe, Tetsuya; Akiba, Masato

    2005-03-01

    Hydrogen permeation fluxes of the reduced activation ferritic steel F82H were quantitatively measured by a newly proposed method, vacuum thermo-balance method, for a precise estimation of tritium leakage in a fusion reactor. We prepared sample capsules made of F82H, which enclosed hydrogen gas. The hydrogen in the capsules permeated through the capsule wall, and subsequently desorbed from the capsule surface during isothermal heating. The vacuum thermo-balance method allows simultaneous measurement of the hydrogen permeation flux by two independent methods, namely, the net weight reduction of the sample capsule and exhaust gas analysis. Thus the simultaneous measurements by two independent methods increase the reliability of the permeability measurement. When the gas pressure of enclosed hydrogen was 0.8 atm at the sample temperature of 673 K, the hydrogen permeation flux of F82H obtained by the net weight reduction and the exhaust gas analysis was 0.75x10 18 (H 2 /m 2 s) and 2.2x10 18 (H 2 /m 2 s), respectively. The ratio of the hydrogen permeation fluxes obtained by the net weight reduction to that measured by the exhaust gas analysis was in the range from 1/4 to 1/1 in this experiment. The temperature dependence of the estimated permeation flux was similar in both methods. Taking the uncertainties of both measurements into consideration, both results are supposed to be consistent. The enhancement of hydrogen permeation flux was observed from the sample of which outer surface was mechanically polished. Through the present experiments, it has been demonstrated that the vacuum thermo-balance method is effective for the measurement of hydrogen permeation rate of F82H. (author)

  13. Analysis of transient permeation behavior of hydrogen isotope caused by abrupt temperature change of first wall and blanket wall material

    International Nuclear Information System (INIS)

    Yamawaki, Michio; Tanaka, Satoru; Kiyoshi, Tsukasa

    1989-01-01

    To obtain further information on the transient permeation behavior of hydrogen isotopes as caused by an abrupt temperature change, numerical calculations were carried out for two typical metals, nickel and vanadium. Deuterium permeation through nickel is analyzed as a typical case of bulk-diffusion-limited permeation. Its transient behavior changed dramatically according to the specimen thickness. The transient behavior, in general, is separated into two parts, initial and latter period behaviors. Conditions which cause such a separation were evaluated. Evaluation of the hydrogen diffusivity and solubility by an analysis of transient curves of hydrogen permeation was carried out. The transient behavior of simultaneous gas- and ion-driven hydrogen permeation through vanadium was also analyzed. Overshooting of the hydrogen permeation rate appears with an abrupt temperature increase. Increasing the impinging ion flux causes the overshooting peak to become sharper, and also reduces the change of the steady-state permeation rate to be attained after the temperature change compared with the initial value. (orig.)

  14. Analysis of hydrogen content and distribution in hydrogen storage alloys using neutron radiography

    International Nuclear Information System (INIS)

    Sakaguchi, Hiroki; Hatakeyama, Keisuke; Satake, Yuichi; Esaka, Takao; Fujine, Shigenori; Yoneda, Kenji; Kanda, Keiji

    2000-01-01

    Small amounts of hydrogen in hydrogen storage alloys, such as Mg 2 Ni, were detected using neutron radiography (NRG). Hydrogen concentrations in a hydrogenated solid solution were determined by this technique. Furthermore, we were able to obtain NRG images for an initial stage of hydrogen absorption in the hydrogen storage alloys. NRG would be a new measurement method to clarify the behavior of hydrogen in hydrogen storage alloys. (author)

  15. Diffusion of hydrogen in Pd-(Ce, Y, B) alloys

    International Nuclear Information System (INIS)

    Sakamoto, Y.; Kaneko, H.; Tsukahara, T.; Hirata, S.

    1987-01-01

    The study has been carried out to determine the diffusivity of hydrogen in Pd alloys containing Ce, Y and B in atom fractions up to θ/sub μ/ = 0.1 by an electrochemical permeation method, and to examine the lattice dilation effect on the diffusivity in these alloys. Ce and Y have been chosen because the solid solubility of both in Pd is about 13 at% in spite of the very large atomic size-factor difference between Pd and the solutes, and thus the expansion of the Pd lattice by Ce and Y is much larger than by Ag. Furthermore, it is of interest that the partial enthalpy of the dissolved hydrogen at infinite dilution ΔH 0 /sub H/ for Ce and Y is much smaller than for Pd. On the other hand, B atom also expands the Pd lattice in a way similar to Y, and sometimes B atoms may dissolve in the octahedral interstitial sites in the same way as hydrogen atoms

  16. Determination of trapping parameters and the chemical diffusion coefficient from hydrogen permeation experiments

    International Nuclear Information System (INIS)

    Svoboda, J.; Mori, G.; Prethaler, A.; Fischer, F.D.

    2014-01-01

    Highlights: • A modeling study for diffusion of hydrogen with traps is presented. • Introduction of a new chemical diffusion coefficient. • Density of traps and average depth of traps can be determined. • Lattice diffusion and sub-surface concentration of atomic hydrogen can be determined. - Abstract: An improved diffusion theory accounting for trapping effects is applied to evaluation of hydrogen permeation experiments performed for pure iron and pearlitic and martensitic steels. The trapping parameters as molar volume and depth of traps are determined by fitting experiments by simulations based on the theory. The concentration-dependent chemical diffusion coefficient of hydrogen is extracted indicating that the trapping effect on diffusion in pure iron and pearlitic steel is negligible. However, it is significant for martensitic steel, for which the chemical diffusion coefficient cannot be considered as concentration-independent as it is established in current standards

  17. Hydrogen permeation resistant heat pipe for bi-modal reactors. Final report, October 1, 1994--September 30, 1995

    International Nuclear Information System (INIS)

    North, M.T.; Anderson, W.G.

    1995-01-01

    The principal objective of this program was to demonstrate technology that will make a sodium heat pipe tolerant of hydrogen permeation for a bimodal space reactor application. Special focus was placed on techniques which enhance the permeation of hydrogen out of the heat pipe. Specific objectives include: define the detailed requirements for the bimodal reactor application; design and fabricate a prototype heat pipe tolerant of hydrogen permeation; and test the prototype heat pipe and demonstrate that hydrogen which permeates into the heat pipe is removed or reduced to acceptable levels. The results of the program were fully successful. Analyses were performed on two different heat pipe designs and an experimental heat pipe was fabricated and tested. A model of the experimental heat pipe was developed to predict the enhancement in the hydrogen permeation rate out of the heat pipe. A significant improvement in the rate at which hydrogen permeates out of a heat pipe was predicted for the use of the special condenser geometry developed here. Agreement between the model and the experimental results was qualitatively good. Inclusion of the additional effects of fluid flow in the heat pipe are recommended for future work

  18. Study of peculiarities of hydrogen isotopes mixture permeation through low activated steel F82H

    International Nuclear Information System (INIS)

    Kenzhin, Ye.A.; Tazhibayeva, I.L; Kulsartov, T.V.; Shestakov, V.P.; Chikhray, Ye.V.; Afanasev, S.E.; Zheldak, Yu.L.

    2003-01-01

    Full text: The problem of diffusion tritium leakage through blanket materials of future fusion device makes some constructive difficulties concerned with protection of personnel and environment and also with losses of tritium, which is planned to be used in the same device. One of the little-studied problems in the tritium leakage process in Fusion Power Plant is that in fact tritium will penetrate through materials while other hydrogen isotopes are present. These are deuterium and hydrogen which always are present in metals. Therefore, for evaluation of tritium leakage in future Fusion Power Plant under such conditions it is necessary to have experimental data about permeation of these hydrogen isotopes through the structure materials.One of proposed structure materials of fusion reactor blanket is low activated steel F82H. The experiment results on evaluation of .hydrogen, deuterium and its mixture interaction parameters with steel F82H are shown in this work. The tests were carried out within temperature range 273-973 K under inlet hydrogen pressure of 100-2000 Pa. Diffusivity, deuterium and hydrogen permeation constants for low activated steel F82H was determined from experiment results. Those experimental results were used for created phenomenology model which describes hydrogen isotope penetration through tube sample from hydrogen isotopes mixture. That model was used so determining the ratios of desorption rates (D-D, D-H, H-H) on outlet side of sample. Using of so obtained results, we can correctly evaluate, the titanium leakage from blanket of fusion machine which will be constructed using low activated steel F82H

  19. Analysis of the hydrogen permeation properties of TiN-TiC bilayers deposited on martensitic stainless steel

    International Nuclear Information System (INIS)

    Checchetto, R.; Horino, Y.; Benamati, G.

    1996-01-01

    The efficiency of TiN-TiC bilayer coatings, deposited by ion-beam-assisted deposition on martensitic steel, as a hydrogen permeation barrier was investigated by a gas phase method; the hydrogen permeability in the TiN-TiC bilayers is very low, at least 10 4 times lower than in the steel substrate in the temperature interval 470-570 K. Possible physical mechanisms, responsible for the reduced permeability of the ceramic bilayers, are discussed. In particular, from our experimental results, it can be concluded that chemisorption and/or hydrogen jumping from surface sites to the first subsurface atomic layer represents the hydrogen permeation limiting process. (orig.)

  20. Hydrogen in niobium-titanium alloys

    International Nuclear Information System (INIS)

    Silva, J.R.G. da; Cabral, F.A.O.; Florencio, O.

    1985-01-01

    High purity Nb-Ti polycrystalline alloys were doped with hydrogen in equilibrium with the gaseous atmosphere at a pressure of 80 torr. at different temperatures. The partial molar enthalpy and entropy of the hydrogen solution at high dilution, ΔH sup(-) 0 and ΔS sup(-) 0 , were calculated from the equilibrium solubility data. The ΔH sup(-) 0 values are compared with the electron screened proton model of metal-hydrogen solutions. The addition of titanium to niobium has the effect to increase the hydrogen solubility at a given equilibrium temperature. (Author) [pt

  1. Investigation of non-magnetic alloys for the suppression of tritium permeation

    International Nuclear Information System (INIS)

    1980-07-01

    The present work was aimed at identification of alloys which might combine low tritium permeation with other properties desired in fusion reactor vessels, heat exchangers, lithium-handling plumbing and other components likely to contain tritium. These properties include low radiation damage, low magnetic permeability, high temperature strength, and compatibility with potential heat transfer and blanket materials. The work consisted of two tasks: problem definition, and literature search and analysis. Task I was complicated by the incomplete status of fusion reactor development, particularly with respect to selection of coolant and blanket materials and temperatures. The approach taken was to establish a probable range of requirements

  2. Palladium alloy membrane process for the treatment of hydrogen isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Hongsuk; Paek, Seungwoo; Lee, Minsoo; Kim, Kwangrag; Yim, Sungpaal; Ahn, Dohee [KAERI, Daejeon (Korea, Republic of); Shim, Myunghwa [Univ. of Science and Technology, Daejeon (Korea, Republic of)

    2005-11-15

    Tritium is a radioactive isotope of hydrogen and it has a half-life of 12.3 years; it decays to He-3 by emitting a low energy beta radiation with an average energy of 5.7 keV and a maximum energy of 18.6 keV. Transfer of environmentally tritiated water to humans takes place via an inhalation, diffusion through the skin and ingestion. Radioactive waste containing tritium is continuously generated by the nuclear industry in, for example, nuclear reactor operations and a radioisotope production, as well as in medical research. Methods for removing tritium from liquid waste provide an alternative to the control of tritium emissions and a personnel exposure. A combined electrolysis and catalytic exchange process is a very effective method to remove small quantities of tritium from light or heavy waste water streams. The process consists of three main steps: (a) A front end step that exchanges the tritium to a less toxic hydrogen phase. This can be performed either through a chemical exchange in the presence of a platinum supported catalyst or through the decomposition of water. (b) A back end process that purifies the tritiated hydrogen gas which evolved from the electrolysis. This can be performed through a palladium alloy membrane separator. (c) A means of storing the concentrated gas safely. Uranium is used if the storage is temporary; titanium is usually employed for long term storage. To gain a better understanding of the tritiated hydrogen gas purification process, a mathematical model of the palladium alloy membrane has been used. This model is described herein, and the representative results of the model calculations are presented. The authors selected the palladium alloy membrane for the hydrogen purification process by considering the membrane properties, such as a chemical resistance, mechanical stability, thermal stability, high permeability, and a stable operation. The solution-diffusion model can be a useful tool for designing a membrane permeator. The

  3. Palladium alloy membrane process for the treatment of hydrogen isotopes

    International Nuclear Information System (INIS)

    Chung, Hongsuk; Paek, Seungwoo; Lee, Minsoo; Kim, Kwangrag; Yim, Sungpaal; Ahn, Dohee; Shim, Myunghwa

    2005-01-01

    Tritium is a radioactive isotope of hydrogen and it has a half-life of 12.3 years; it decays to He-3 by emitting a low energy beta radiation with an average energy of 5.7 keV and a maximum energy of 18.6 keV. Transfer of environmentally tritiated water to humans takes place via an inhalation, diffusion through the skin and ingestion. Radioactive waste containing tritium is continuously generated by the nuclear industry in, for example, nuclear reactor operations and a radioisotope production, as well as in medical research. Methods for removing tritium from liquid waste provide an alternative to the control of tritium emissions and a personnel exposure. A combined electrolysis and catalytic exchange process is a very effective method to remove small quantities of tritium from light or heavy waste water streams. The process consists of three main steps: (a) A front end step that exchanges the tritium to a less toxic hydrogen phase. This can be performed either through a chemical exchange in the presence of a platinum supported catalyst or through the decomposition of water. (b) A back end process that purifies the tritiated hydrogen gas which evolved from the electrolysis. This can be performed through a palladium alloy membrane separator. (c) A means of storing the concentrated gas safely. Uranium is used if the storage is temporary; titanium is usually employed for long term storage. To gain a better understanding of the tritiated hydrogen gas purification process, a mathematical model of the palladium alloy membrane has been used. This model is described herein, and the representative results of the model calculations are presented. The authors selected the palladium alloy membrane for the hydrogen purification process by considering the membrane properties, such as a chemical resistance, mechanical stability, thermal stability, high permeability, and a stable operation. The solution-diffusion model can be a useful tool for designing a membrane permeator. The

  4. Theoretical Studies of Hydrogen Storage Alloys.

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, Hannes

    2012-03-22

    Theoretical calculations were carried out to search for lightweight alloys that can be used to reversibly store hydrogen in mobile applications, such as automobiles. Our primary focus was on magnesium based alloys. While MgH{sub 2} is in many respects a promising hydrogen storage material, there are two serious problems which need to be solved in order to make it useful: (i) the binding energy of the hydrogen atoms in the hydride is too large, causing the release temperature to be too high, and (ii) the diffusion of hydrogen through the hydride is so slow that loading of hydrogen into the metal takes much too long. In the first year of the project, we found that the addition of ca. 15% of aluminum decreases the binding energy to the hydrogen to the target value of 0.25 eV which corresponds to release of 1 bar hydrogen gas at 100 degrees C. Also, the addition of ca. 15% of transition metal atoms, such as Ti or V, reduces the formation energy of interstitial H-atoms making the diffusion of H-atoms through the hydride more than ten orders of magnitude faster at room temperature. In the second year of the project, several calculations of alloys of magnesium with various other transition metals were carried out and systematic trends in stability, hydrogen binding energy and diffusivity established. Some calculations of ternary alloys and their hydrides were also carried out, for example of Mg{sub 6}AlTiH{sub 16}. It was found that the binding energy reduction due to the addition of aluminum and increased diffusivity due to the addition of a transition metal are both effective at the same time. This material would in principle work well for hydrogen storage but it is, unfortunately, unstable with respect to phase separation. A search was made for a ternary alloy of this type where both the alloy and the corresponding hydride are stable. Promising results were obtained by including Zn in the alloy.

  5. The behaviour of hydrogen in Excel alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ells, C.E. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Coleman, C.E. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Cheadle, B.A. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Sagat, S. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Rodgers, D.K. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.

    1995-12-15

    To enable mitigation of deleterious effects from hydride on the mechanical behaviour of Excel alloy, Zr-3.5 wt.% Sn-0.8 wt.% Mo-0.8 wt.% Nb, the behaviours of hydrogen and hydride in the alloy have been studied. Properties of interest are the terminal solid solubility, diffusivity, heat of transport, stress reorientation, and the initiation and crack growth of delayed hydride cracking. The results obtained are compared with those of other zirconium-rich alloys, notably Zr-2.5 wt.% Nb. (orig.)

  6. Influence of the P content on the transport parameters of hydrogen in Fe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Peñalva, I., E-mail: igor.penalva@ehu.es [University of the Basque Country (UPV/EHU), Department of Nuclear Engineering & Fluid Mechanics, Faculty of Engineering, Alda. Urquijo s/n, 48013 Bilbao (Spain); Alberro, G.; Legarda, F. [University of the Basque Country (UPV/EHU), Department of Nuclear Engineering & Fluid Mechanics, Faculty of Engineering, Alda. Urquijo s/n, 48013 Bilbao (Spain); Ortiz, C.J.; Vila, R. [CIEMAT, Avda. Complutense 22, 28040 Madrid (Spain)

    2015-10-15

    Highlights: • Gas permeation technique was used to study hydrogen diffusive transport parameters. • Four Fe alloys were analyzed to study the influence of the P content. • Increase in the P content leads to smaller values of permeability and diffusivity. • Trapping effects were observed at temperatures below 473 K for alloys containing P. - Abstract: In this work, the hydrogen transport parameters of permeability (ϕ), diffusivity (D) and Sieverts’ constant (K{sub S}) were experimentally measured in four Fe alloys supplied by the European Fusion Development Agreement (EFDA), by means of the gas evolution permeation technique. The samples had controlled chemical alloying element contents and microstructure. The experimental temperature range explored was from 423 K to 823 K and the high purity hydrogen loading pressures from 10{sup 3} Pa to 1.5·10{sup 5} Pa. The main objective of this work was to determine the influence of the P content of the alloy in the transport parameters of hydrogen. Two of the samples, pure Fe and FeC, contained negligible quantities of P (less than 5 ppm in weight), whereas the other two, FeP and FeCP, had the same metallurgical composition as their corresponding pair, with the only difference in the phosphorus content (89 ppm in weight and 88 ppm in weight, respectively). The experimental permeation results were analyzed using a non-linear least square fitting. The final resulting values of the aforementioned transport parameters were paired off in order to determine the effect of the P content: pure Fe versus FeP and FeC versus FeCP. We observed that the permeability obtained for all the samples follows an Arrhenius law in each case. In general terms, the increase of the P content in the alloy leads to smaller values of the permeability showing a decrease in the permeation activation energy. Regarding diffusivity and Sieverts’ constant, trapping effects have been observed for the alloys containing P. This phenomenon was

  7. Fatigue behavior of niobium--hydrogen alloys

    International Nuclear Information System (INIS)

    Chung, D.W.; Stoloff, N.S.

    1978-01-01

    The effects of hydrogen on room temperature fatigue behavior of niobium were investigated under both high frequency stress control and low frequency strain control conditions, in air. Hydrogen markedly improved the fatigue life in high frequency tests, while low frequency tests resulted in decreased fatigue life with increasing hydrogen content. Notches in hydrogen-charged alloys reduced high cycle life significantly but had little effect on low cycle tests. Fracture surfaces of annealed niobium mainly exhibited striations, with numerous cracks originating at troughs of striated bands in both stress and strain control tests. The fracture mode for alloys with hydrogen in solution was mixed, with striations interspersed with cleavage facets at high frequencies but generally cleavage steps at low frequencies. For the hydrided alloys, distinctive steps of mixed ductile-brittle appearance were revealed under high frequency conditions, but large cleavage facets only were observed for low frequency tests. The results are discussed in terms of the effects of hydrogen on the cyclic strain hardening rate, as well as on fatigue strength and ductility of niobium

  8. Study of the cathodic depolarization theory with hydrogen permeation and the bacteria Desulfovibrio desulfuricans

    International Nuclear Information System (INIS)

    Romero, M. F. de; Duque, Z.; Rinco, O. T. de; Perez, O.; Araujo, I.

    2003-01-01

    A Desulfovibrio desulfuricans ssp. desulfuricans (SRB) was used to study the permeation of hydrogen, using a Devanatan and Stachurski cell and a palladium sheet. The aim was to evaluate cathodic depolarization as a Sulfate-Reducing Bacteria action mechanisms in Microbiologically Induced Corrosion. The permeation tests were run with and without cathodic polarization, using a sterile deaerated culture medium inoculated with 10% SRB concentrated at 10''8 cell/ml. the results indicate bacterial growth in the order of 10''9-10''10 cel/ml after 18 h both in the polarized and non-polarized, tests, indicating that SRB developed regardless of the surface polarized as a source of H''0, generating H 2 S as a product of the anaerobic respiration. It was also determined that, without cathodic polarization, the conditions are not enough to reduce the H* generated by the H 2 S dissociation (pd is not susceptible to corrosion at this condition). On the other hand, cathodic polarization increased the permeation current, which was associated with the maximum enzymatic activity phase of the bacteria. (Author) 8 refs

  9. Toward enhanced hydrogen generation from water using oxygen permeating LCF membranes

    KAUST Repository

    Wu, Xiao-Yu

    2015-01-01

    © the Owner Societies. Hydrogen production from water thermolysis can be enhanced by the use of perovskite-type mixed ionic and electronic conducting (MIEC) membranes, through which oxygen permeation is driven by a chemical potential gradient. In this work, water thermolysis experiments were performed using 0.9 mm thick La0.9Ca0.1FeO3-δ (LCF-91) perovskite membranes at 990 °C in a lab-scale button-cell reactor. We examined the effects of the operating conditions such as the gas species concentrations and flow rates on the feed and sweep sides on the water thermolysis rate and oxygen flux. A single step reaction mechanism is proposed for surface reactions, and three-resistance permeation models are derived. Results show that water thermolysis is facilitated by the LCF-91 membrane especially when a fuel is added to the sweep gas. Increasing the gas flow rate and water concentration on the feed side or the hydrogen concentration on the sweep side enhances the hydrogen production rate. In this work, hydrogen is used as the fuel by construction, so that a single-step surface reaction mechanism can be developed and water thermolysis rate parameters can be derived. Both surface reaction rate parameters for oxygen incorporation/dissociation and hydrogen-oxygen reactions are fitted at 990 °C. We compare the oxygen fluxes in water thermolysis and air separation experiments, and identify different limiting steps in the processes involving various oxygen sources and sweep gases for this 0.9 mm thick LCF-91 membrane. In the air feed-inert sweep case, the bulk diffusion and sweep side surface reaction are the two limiting steps. In the water feed-inert sweep case, surface reaction on the feed side dominates the oxygen permeation process. Yet in the water feed-fuel sweep case, surface reactions on both the feed and sweep sides are rate determining when hydrogen concentration in the sweep side is in the range of 1-5 vol%. Furthermore, long term studies show that the surface

  10. Oxide characterization and hydrogen behaviors of Zr-based alloys

    International Nuclear Information System (INIS)

    Kim, Y. S.; Kim, D. J.; Kwon, S. H.; Lee, H. S.; Oh, S. J.; Yim, B. J.; Son, S. B.; Yun, S. P.

    2006-03-01

    The work scope and contents of the research are as follows : basic properties of zirconium alloys, hydrogen pick-up mechanism of zirconium alloy, effects of hydride on the corrosion behaviors of zirconium alloys, estimation on stress of oxide layer in the zirconium alloy, microstructure and characteristic of oxide in pre-hydrided zirconium alloys

  11. Modelling hydrogen permeation in a hydrogen effusion probe for monitoring corrosion of carbon steels

    International Nuclear Information System (INIS)

    Santiwiparat, P.; Rirksomboon, T.; Steward, F.R.; Lister, D.H.; Cook, W.G.

    2015-01-01

    Hydrogen accumulation inside carbon steel and stainless steel devices shaped like cylindrical cups attached to a pipe containing hydrogen gas was modelled with MATLAB software. Hydrogen transfer around the bottom of the cups (edge effect) and diffusion through the cup walls (material effect) were accounted for. The variation of hydrogen pressure with time was similar for both materials, but the hydrogen plateau pressures in stainless steel cups were significantly higher than those in carbon steel cups. The geometry of the cup also affected the plateau pressure inside the cup. (author)

  12. Theoretical description of quantum mechanical permeation of graphene membranes by charged hydrogen isotopes

    Science.gov (United States)

    Mazzuca, James W.; Haut, Nathaniel K.

    2018-06-01

    It has been recently shown that in the presence of an applied voltage, hydrogen and deuterium nuclei can be separated from one another using graphene membranes as a nuclear sieve, resulting in a 10-fold enhancement in the concentration of the lighter isotope. While previous studies, both experimental and theoretical, have attributed this effect mostly to differences in vibrational zero point energy (ZPE) of the various isotopes near the membrane surface, we propose that multi-dimensional quantum mechanical tunneling of nuclei through the graphene membrane influences this proton permeation process in a fundamental way. We perform ring polymer molecular dynamics calculations in which we include both ZPE and tunneling effects of various hydrogen isotopes as they permeate the graphene membrane and compute rate constants across a range of temperatures near 300 K. While capturing the experimentally observed separation factor, our calculations indicate that the transverse motion of the various isotopes across the surface of the graphene membrane is an essential part of this sieving mechanism. An understanding of the multi-dimensional quantum mechanical nature of this process could serve to guide the design of other such isotopic enrichment processes for a variety of atomic and molecular species of interest.

  13. Theoretical description of quantum mechanical permeation of graphene membranes by charged hydrogen isotopes.

    Science.gov (United States)

    Mazzuca, James W; Haut, Nathaniel K

    2018-06-14

    It has been recently shown that in the presence of an applied voltage, hydrogen and deuterium nuclei can be separated from one another using graphene membranes as a nuclear sieve, resulting in a 10-fold enhancement in the concentration of the lighter isotope. While previous studies, both experimental and theoretical, have attributed this effect mostly to differences in vibrational zero point energy (ZPE) of the various isotopes near the membrane surface, we propose that multi-dimensional quantum mechanical tunneling of nuclei through the graphene membrane influences this proton permeation process in a fundamental way. We perform ring polymer molecular dynamics calculations in which we include both ZPE and tunneling effects of various hydrogen isotopes as they permeate the graphene membrane and compute rate constants across a range of temperatures near 300 K. While capturing the experimentally observed separation factor, our calculations indicate that the transverse motion of the various isotopes across the surface of the graphene membrane is an essential part of this sieving mechanism. An understanding of the multi-dimensional quantum mechanical nature of this process could serve to guide the design of other such isotopic enrichment processes for a variety of atomic and molecular species of interest.

  14. Hydrogen storage in Ti-Mn-(FeV) BCC alloys

    International Nuclear Information System (INIS)

    Santos, S.F.; Huot, J.

    2009-01-01

    Recently, the replacement of vanadium by the less expensive (FeV) commercial alloy has been investigated in Ti-Cr-V BCC solid solutions and promising results were reported. In the present work, this approach of using (FeV) alloys is adopted to synthesize alloys of the Ti-Mn-V system. Compared to the V-containing alloys, the alloys containing (FeV) have a smaller hydrogen storage capacity but a larger reversible hydrogen storage capacity, which is caused by the increase of the plateau pressure of desorption. Correlations between the structure and the hydrogen storage properties of the alloys are also discussed.

  15. Alloys having improved resistance to hydrogen embrittlement

    International Nuclear Information System (INIS)

    Kane, R.D.; Greer, J.B.; Jacobs, D.F.; Berkowitz, B.J.

    1983-01-01

    The invention involves a process of improving the hydrogen embrittlement resistance of a cold-worked high yield strength nickel/cobalt base alloy containing chromium, and molybdenum and/or tungsten and having individual elemental impurity concentrations as measured by Auger spectroscopy at the crystallographic boundaries of up to about 1 Atomic percent. These elemental impurities are capable of becoming active and mobile at a temperature less than the recrystallization temperature of the alloy. The process involves heat treating the alloy at a temperature above 1300 degrees F but below the temperature of recrystallization for a time of from 1/4 to 100 hours. This is sufficient to effect a reduction in the level of the elemental impurities at the crystallographic boundaries to the range of less than 0.5 Atomic percent without causing an appreciable decrease in yield strength

  16. Determination of hydrogen in metals and alloys

    International Nuclear Information System (INIS)

    Sayi, Y.S.; Ramanjaneyulu, P.S.; Ramakumar, K.L.

    2008-01-01

    Hydrogen will be invariably present in all materials. Its presence in excess is harmful and sometimes calamitous. Hydrogen embrittlement can occur quite readily in most high strength materials, irrespective of their composition or structure. It is therefore essential to maintain low levels of hydrogen. To know the amount of hydrogen present in the materials, it is essential to determine it with high degree of precision and accuracy. It is required to give the uncertainty associated with the measurement to increase the confidence on measurements. Several methodologies are available for the determination of hydrogen. It its isotope, deuterium, also co-exists it becomes all the more difficult to determine these individually. Hot vacuum extraction cum quadrupole mass spectrometry (HVE-QMS) developed in our laboratory to determine hydrogen and deuterium is routinely employed for the determination of hydrogen and deuterium in metals and alloys. The present paper deals in detail about our experiences with HVE-QMS and estimation of uncertainty associated in this methodology. (author)

  17. Studies of the permeation and diffusion of tritium and hydrogen in TFTR

    International Nuclear Information System (INIS)

    Garber, H.J.

    1975-10-01

    This report documents the main features of studies conducted on the permeation and diffusion of tritium and hydrogen through the stainless steel sections comprising the vacuum vessel of TFTR. The overall conclusion of these studies is that tritium releases to the environment resulting from TFTR operations under normal conditions will be very small, less than one curie per year. A basis is described for predicting the magnitudes of the applicable transport properties for tritium-austenitic stainless steel systems as derived from a survey of the technical literature on tritium transport. The key characteristics of the TFTR vacuum vessel that are involved in the permeation and diffusion calculations are given. Information is given regarding the contemplated plasma scenarios and associated required gas injection quantities. Various issues involved in the bakeout of the vacuum vessel are discussed; focussing principally on the problems associated with in-situ bakeout and related means to reduce outgassing from the TFTR vessel and vacuum pumping system hardware. The anticipated tritium releases are studied considering the diffusion transients

  18. A model to predict the permeation of type IV hydrogen tanks

    Energy Technology Data Exchange (ETDEWEB)

    Bayle, Julien; Perreux, Dominique; Chapelle, David; Thiebaud, Frederic [MaHyTec, Dole (France); Nardin, Philippe [Franche Comte Univ. (France)

    2010-07-01

    In the frame of the certification process of the type IV hydrogen storage tanks MaHyTec aims to manufacture, this innovative SME is developing a numerical model dedicated to the study of permeation issues. Such an approach aims at avoiding complicated, time-consuming and expensive testing. Experimental results obtained under real conditions can moreover be significantly influenced by the scattering of material properties and liner dimensions. From simple testing on small-size flat membranes, the model allows to predict the gas diffusion flow through the whole structure by means of numerous parameters. On every step, theory can be compared with the results obtained from the samples. This document presents a brief review of the mathematical theory describing gas diffusion and the different aspects of the study for better understanding the proposed approach. (orig.)

  19. Effect of composition on diffusible hydrogen content and hydrogen assisted cracking of steel welds

    International Nuclear Information System (INIS)

    Albert, S.K.; Ramasubbu, V.; Bhaduri, A.K.; Parvathavarthini, N.

    2008-01-01

    Study of hydrogen assisted cracking and measurement of diffusible hydrogen content in different Cr-Mo steel welds showed that for identical conditions, susceptibility to cracking increased and diffusible hydrogen content decreased with increase in alloy content. Hydrogen permeation studies showed that hydrogen diffusivity decreases and solubility increases with increase in alloy content. Thus decrease in diffusible hydrogen content with increase in alloying is attributed to increase in apparent solubility and decrease in apparent diffusivity of hydrogen with increase in alloy content. Analysis of the results indicates that variation of diffusible hydrogen content and apparent diffusivity of hydrogen with alloy content can be represented as a function of alloy composition. (author)

  20. Iron-titanium-mischmetal alloys for hydrogen storage

    Science.gov (United States)

    Sandrock, Gary Dale

    1978-01-01

    A method for the preparation of an iron-titanium-mischmetal alloy which is used for the storage of hydrogen. The alloy is prepared by air-melting an iron charge in a clay-graphite crucible, adding titanium and deoxidizing with mischmetal. The resultant alloy contains less than about 0.1% oxygen and exhibits a capability for hydrogen sorption in less than half the time required by vacuum-melted, iron-titanium alloys.

  1. Hydrogen solubility in austenite of Fe-Ni-Cr alloys

    International Nuclear Information System (INIS)

    Zhirnova, V.V.; Mogutnov, B.M.; Tomilin, I.A.

    1981-01-01

    Hydrogen solubility in Fe-Ni-Cr alloys at 600-1000 deg C is determined. Hydrogen solubility in ternary alloys can not be predicted on the basis of the data on its solubility in binary Fe-Ni, Fe-Cr alloys. Chromium and nickel effect on hydrogen solubility in iron is insignificant in comparison with the effect of these elements on carbon or nitrogen solubility [ru

  2. Modeling of roughness effect on hydrogen permeation in a low carbon steel

    Directory of Open Access Journals (Sweden)

    Carreño, J. A.

    2003-12-01

    Full Text Available A model is presented to evaluate the effect of the roughness and the profile of concentration of hydrogen in a low carbon steel. The model takes advantage of the Fick's Second Law, to predict the transport of hydrogen in the steel. The problem is treated as a variational one and its space solution is made numerically by means of the Finite Elements Method, while the temporal equation is solved via the Finite Differences Method, in order to determine the concentration profiles of Hydrogen in the steel and to quantify the roughness effect. Simultaneously, bipotentiostatic hydrogen permeation test were performed to evaluate the coefficient of mass transfer.

    El presente trabajo modela el efecto de la rugosidad y el perfil de concentración de hidrógeno en un acero, tomando como punto de partida la segunda ley de Fick para explicar el transporte de hidrógeno en el acero. El problema se trata como un problema variacional y su solución espacial se hace numéricamente por el Método de Elementos Finitos, mientras que la temporal por el Método de Diferencias Finitas, siendo estas las herramientas utilizadas para determinar los perfiles de concentración y cuantificar el efecto superficial presentado en este tipo de fenómeno. Además, a partir de la teoría se obtienen ecuaciones algebraicas que determinan el efecto que tiene la preparación superficial y el coeficiente de transferencia de masa con la permeación y concentración de hidrógeno en el acero.

  3. Solubility and diffusion of hydrogen in pure metals and alloys

    International Nuclear Information System (INIS)

    Wipf, H.

    2001-01-01

    Basic facts are presented of the absorption of hydrogen gas by metals and the diffusion of hydrogen in metals. Specifically considered are crystalline metals without defects and lattice disorder (pure metals), low hydrogen concentrations and the possibility of high hydrogen gas pressures. The first introductory topic is a short presentation of typical phase diagrams of metal hydrogen systems. Then, hydrogen absorption is discussed and shown to be decisively determined by the enthalpy of solution, in particular by its sign which specifies whether absorption is exothermic or endothermic. The formation of high-pressure hydrogen gas bubbles in a metal, which can lead to blistering, is addressed. It is demonstrated that bubble formation will, under realistic conditions, only occur in strongly endothermically hydrogen absorbing metals. The chief aspects of hydrogen diffusion in metals are discussed, especially the large size of the diffusion coefficient and its dependence on lattice structure. It is shown that forces can act on hydrogen in metals, causing a directed hydrogen flux. Such forces arise, for instance, in the presence of stress and temperature gradients and can result in local hydrogen accumulation with potential material failure effects. The final aspect discussed is hydrogen permeation, where the absorption behavior of the hydrogen is found to be in general more decisive on the permeation rate than the value of the diffusion coefficient. (orig.)

  4. Hydrogen embrittlement of titanium and its alloys - a literature review

    International Nuclear Information System (INIS)

    Aho-Mantila, I.; Haemaelaeinen, H.

    1986-05-01

    Hydrogen embrittlement data of titanium and its alloys is reviewed. Especially the results obtained in spent nuclear fuel repository conditions with commercially pure titanium and TiCode-12 alloy are examined. The results show that the mechanical properties of titanium are not much affected by hydrogen when tested by smooth specimens. Much greater effects can be expected with notched fracture mechanics specimens. However, only limeted data is available. Hydrogen distribution in titanium is affected by stress, alloy composition and temperature gradients. In order to model the hydrogen-induced crack growth in titanium much more mechanistic work is needed especially to understand the behaviour of hydrogen in crack tip stress field. (author)

  5. The influence of surface roughness on the hydrogen permeation of type API 5L-X52 steel

    International Nuclear Information System (INIS)

    Requiz, R.; Vera, N.; Camero, S.

    2004-01-01

    The influence of surface roughness on the corrosion and hydrogen permeation behaviour was evaluated on a type API 5L-52 steel in dearated 0.1M NaSO 4 at pH=2. Potentiodynamic polarization curves were employed to determine the electrochemical behaviour of the steel, while the Devanathan-Stachurski technique was used to estimate the hydrogen permeation rate. Additionally, the surface roughness profiles were obtained in order to correlate the changes in the hydrogen perkeation rate with different metal surface finishings. The obtained results clearly demonstrate that when the roughness parameters have larger values, the cathodic current of hydrogen evolution increases while the hydrogen entry rate decreases. This effect can be attributed to the microstructural defects induced at the steel surface, such as dislocations, which increase the catalytic activity of the atomic hydrogen favouring its recombination. Also, these defects could allow the atomic hydrogen to remain adsorbed on the steel surface. Both effects could hinder the hydrogen diffusion into the metal since the possibility for this atom of becoming absorbed has been reduced. (Author) 16 refs

  6. Absorption of hydrogen by vanadium-palladium alloys

    International Nuclear Information System (INIS)

    Artman, D.; Lynch, J.F.; Flanagan, T.B.

    1976-01-01

    Pressure composition isotherms (273-373 K) have been determined for the absorption of hydrogen by a series of six palladium alloys (f.c.c) in the composition range from 1 to 8 at.% vanadium. At a given hydrogen content, the equilibrium hydrogen pressure progressively increases with vanadium content. Thermodynamic parameters for the absorption of hydrogen are reported at infinite dilution of hydrogen and for the formation of the nonstoichiometric hydride from the hydrogen-saturated alloy. The relative, partial molar enthalpy of solution of hydrogen at infinite dilution increases slightly with vanadium content. The presence of vanadium, which absorbs hydrogen itself in its normal b.c.c. structure, greatly inhibits the ability of palladium to absorb hydrogen. For example, the isobaric solubility of hydrogen (1 atm, 298K) decreases from H/Pd=0.7 (palladium) to 0.024 (V(6%)-Pd). The lattice expansion due to the presence of interstitial hydrogen has been determined by X-ray diffraction. From these data it can be concluded that the formation of two non-stoichiometric hydride phases does not occur at vanadium contents greater that 5 at.% (298 K). Electrical resistance has been measured as a function of the hydrogen content of the alloys. The electrical resistance increases more markedly with hydrogen content for these alloys than for any of the palladium alloys previously examined. (Auth.)

  7. Investigation of aluminised steel as a barrier to tritium using accelerator-based and hydrogen permeation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Sokhi, R S; Forcey, K S; Ross, D K; Earwaker, L G [Birmingham Univ. (UK). School of Physics and Space Research

    1989-04-01

    Aluminised steel has been proposed as a barrier to tritium permeation in fusion reactors. The properties of these materials as tritium barriers have been studied using accelerator-based techniques and hydrogen permeation methods. The aluminide layers has been characterised by Rutherford backscattering spectroscopy (RBS) and nuclear reaction analysis (NRA) techniques using the 3 MV Dynamitron accelerator based at the School of Physics and Space Research Radiation Centre. The effectiveness of the aluminide layer as a tritium barrier has been measured directly by a conventional permeation apparatus over a range of temperatures. The effect of high temperatures on the structure of the aluminide layer has been examined. Any correlation between the composition of the layer and its effectiveness as a tritium barrier is also discussed. (orig.).

  8. 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.

  9. 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

  10. Meso-microstructural computational simulation of the hydrogen permeation test to calculate intergranular, grain boundary and effective diffusivities

    Energy Technology Data Exchange (ETDEWEB)

    Jothi, S., E-mail: s.jothi@swansea.ac.uk [College of Engineering, Swansea University, Singleton Park, Swansea SA2 8PP (United Kingdom); Winzer, N. [Fraunhofer Institute for Mechanics of Materials IWM, Wöhlerstraße 11, 79108 Freiburg (Germany); Croft, T.N.; Brown, S.G.R. [College of Engineering, Swansea University, Singleton Park, Swansea SA2 8PP (United Kingdom)

    2015-10-05

    Highlights: • Characterized polycrystalline nickel microstructure using EBSD analysis. • Development meso-microstructural model based on real microstructure. • Calculated effective diffusivity using experimental electrochemical permeation test. • Calculated intergranular diffusivity of hydrogen using computational FE simulation. • Validated the calculated computation simulation results with experimental results. - Abstract: Hydrogen induced intergranular embrittlement has been identified as a cause of failure of aerospace components such as combustion chambers made from electrodeposited polycrystalline nickel. Accurate computational analysis of this process requires knowledge of the differential in hydrogen transport in the intergranular and intragranular regions. The effective diffusion coefficient of hydrogen may be measured experimentally, though experimental measurement of the intergranular grain boundary diffusion coefficient of hydrogen requires significant effort. Therefore an approach to calculate the intergranular GB hydrogen diffusivity using finite element analysis was developed. The effective diffusivity of hydrogen in polycrystalline nickel was measured using electrochemical permeation tests. Data from electron backscatter diffraction measurements were used to construct microstructural representative volume elements including details of grain size and shape and volume fraction of grains and grain boundaries. A Python optimization code has been developed for the ABAQUS environment to calculate the unknown grain boundary diffusivity.

  11. Hydrogen storage alloys for nickel/metal hydride battery

    Energy Technology Data Exchange (ETDEWEB)

    Kuriyama, Nobuhiro; Sakai, Tetsuo; Myamura, Hiroshi; Tanaka, Hideaki; Ishikawa, Hiroshi; Uehara, Itsuki [Osaka National Research Inst. (Japan)

    1996-06-01

    Efforts to improve performance of metal hydride electrodes such as substitution of alloy components, heat treatment, and surface treatment intended to change surface and bulk structure of hydrogen storage alloys, mainly LaNi{sub 5} based alloys, are reviewed. The importance of control of morphology is emphasized. (author)

  12. Trace hydrogen extraction from liquid lithium tin alloy

    International Nuclear Information System (INIS)

    Xie Bo; Hu Rui; Xie Shuxian; Weng Kuiping

    2010-01-01

    In order to finish the design of tritium extraction system (TES) of fusion fission hybrid reactor (FFHR) tritium blanket, involving the dynamic mathematical model of liquid metal in contact with a gaseous atmosphere, approximate mathematical equation of tritium in lithium tin alloy was deduced. Moreover, carrying process used for trace hydrogen extraction from liquid lithium tin alloy was investigated with hydrogen being used to simulate tritium in the study. The study results indicate that carrying process is effective way for hydrogen extraction from liquid lithium tin alloy, and the best flow velocity of carrier gas is about 4 L/min under 1 kg alloy temperatures and carrying numbers are the main influencing factors of hydrogen number. Hydrogen extraction efficiency can reach 85% while the alloy sample is treated 6 times at 823 K. (authors)

  13. Hydrogenation properties and microstructure of Ti-Mn-based alloys for hybrid hydrogen storage vessel

    International Nuclear Information System (INIS)

    Shibuya, Masachika; Nakamura, Jin; Akiba, Etsuo

    2008-01-01

    Ti-Mn-based AB 2 -type alloys which are suitable for a hybrid hydrogen storage vessel have been synthesized and evaluated hydrogenation properties. As the third element V was added to Ti-Mn binary alloys. All the alloys synthesized in this work mainly consist of the C14 Laves and BCC phase. In the case of Ti0.5V0.5Mn alloy, the amounts of hydrogen absorption was 1.8 wt.% at 243 K under the atmosphere of 7 MPa H 2 , and the hydrogen desorption pressure was in the range of 0.2-0.4 MPa at 243 K. The hydrogen capacity of this alloy did not saturate under 7 MPa H 2 and seems to increase with hydrogen pressure up to 35 MPa that is estimated working pressure of the hybrid hydrogen storage vessel

  14. Effect of hydrogen on aluminium and aluminium alloys: A review

    DEFF Research Database (Denmark)

    Ambat, Rajan; Dwarakadasa, E.S.

    1996-01-01

    Susceptibility of aluminium and its alloys towards hydrogen embrittlement has been well established. Still a lot of confusion exists on the question of transport of hydrogen and its possible role in stress corrosion cracking. This paper reviews some of the fundamental properties of hydrogen...... in aluminium and its alloys and its effect on mechanical properties. The importance of hydrogen embrittlement over anodic dissolution to explain the stress corrosion cracking mechanism of these alloys is also examined in considerable detail. The various experimental findings concerning the link between...

  15. Solid solutions of hydrogen in niobium, molybdenum and their alloys

    International Nuclear Information System (INIS)

    Ishikawa, T.T.

    1981-01-01

    The solubility of hydrogen in niobium, molybdenum and niobium-molybdenum alloys with varying atomic fraction of molybdenum from 0.15 to 0.75 was measured on the temperature range of 673 0 K to 1273 0 k for one atmosphere hydrogen pressure. The experimental technique involved the saturation of the solvent metal or alloy with hydrogen, followed by quenching and analysis of the solid solution. The results obtained of hydrogen solubility are consistent with the quasi-regular model for the dilute interstitial solid solutions. The partial molar enthalpy and partial molar entropy in excess of the dissolved hydrogen atoms were calculated from data of solubility versus reciprocal doping temperature. The variation of the relative partial molar enthalpy of hydrogen dissolved in niobium-molybdenum alloys, with the increase of molybdenum content of the alloy was analized. (Author) [pt

  16. Measurement of hydrogen solubility and desorption rate in V-4Cr-4Ti and liquid lithium-calcium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.H.; Erck, R.; Park, E.T. [Argonne National Lab., IL (United States)] [and others

    1997-04-01

    Hydrogen solubility in V-4Cr-4Ti and liquid lithium-calcium was measured at a hydrogen pressure of 9.09 x 10{sup {minus}4} torr at temperatures between 250 and 700{degrees}C. Hydrogen solubility in V-4Cr-4Ti and liquid lithium decreased with temperature. The measured desorption rate of hydrogen in V-4Cr-4Ti is a thermally activated process; the activation energy is 0.067 eV. Oxygen-charged V-4Cr-4Ti specimens were also investigated to determine the effect of oxygen impurity on hydrogen solubility and desorption in the alloy. Oxygen in V-4Cr-4Ti increases hydrogen solubility and desorption kinetics. To determine the effect of a calcium oxide insulator coating on V-4Cr-4Ti, hydrogen solubility in lithium-calcium alloys that contained 0-8.0 percent calcium was also measured. The distribution ratio R of hydrogen between liquid lithium or lithium-calcium and V-4Cr-4Ti increased as temperature decreased (R {approx} 10 and 100 at 700 and 250{degrees}C, respectively). However at <267{degrees}C, solubility data could not be obtained by this method because of the slow kinetics of hydrogen permeation through the vanadium alloy.

  17. Measurement of hydrogen solubility and desorption rate in V-4Cr-4Ti and liquid lithium-calcium alloys

    International Nuclear Information System (INIS)

    Park, J.H.; Erck, R.; Park, E.T.

    1997-01-01

    Hydrogen solubility in V-4Cr-4Ti and liquid lithium-calcium was measured at a hydrogen pressure of 9.09 x 10 -4 torr at temperatures between 250 and 700 degrees C. Hydrogen solubility in V-4Cr-4Ti and liquid lithium decreased with temperature. The measured desorption rate of hydrogen in V-4Cr-4Ti is a thermally activated process; the activation energy is 0.067 eV. Oxygen-charged V-4Cr-4Ti specimens were also investigated to determine the effect of oxygen impurity on hydrogen solubility and desorption in the alloy. Oxygen in V-4Cr-4Ti increases hydrogen solubility and desorption kinetics. To determine the effect of a calcium oxide insulator coating on V-4Cr-4Ti, hydrogen solubility in lithium-calcium alloys that contained 0-8.0 percent calcium was also measured. The distribution ratio R of hydrogen between liquid lithium or lithium-calcium and V-4Cr-4Ti increased as temperature decreased (R ∼ 10 and 100 at 700 and 250 degrees C, respectively). However at <267 degrees C, solubility data could not be obtained by this method because of the slow kinetics of hydrogen permeation through the vanadium alloy

  18. Mechanohydrogen processing as an element of hydrogen process of production of titanium alloy parts

    International Nuclear Information System (INIS)

    Egorova, Yu.B.; Il'in, A.A.; Levochkin, A.A.

    2002-01-01

    The regularities of the effect of hydrogen on cutting machinability of titanium alloys are generalized. The main principles of mechanohydrogen treatment are founded. The effectiveness of titanium alloys machining with the use of reversible hydrogen alloying depends on hydrogen content, hydrogen pickup temperature and cutting modes. High-performance technological processes of manufacturing parts and constructions made of titanium alloys are proposed [ru

  19. First principles analysis of hydrogen chemisorption on Pd-Re alloyed overlayers and alloyed surfaces

    DEFF Research Database (Denmark)

    Pallassana, Venkataraman; Neurock, Matthew; Hansen, Lars Bruno

    2000-01-01

    Gradient corrected periodic density functional theory (DFT-GGA) slab calculations were used to examine the chemisorption of atomic hydrogen on various Pd-Re alloyed overlayers and uniformly alloyed surfaces. Adsorption was examined at 33% surface coverage, where atomic hydrogen preferred the thre...

  20. Effect of reversible hydrogen alloying and plastic deformation on microstructure development in titanium alloys

    International Nuclear Information System (INIS)

    Murzinova, M.A.

    2011-01-01

    Hydrogen leads to degradation in fracture-related mechanical properties of titanium alloys and is usually considered as a very dangerous element. Numerous studies of hydrogen interaction with titanium alloys showed that hydrogen may be considered not only as an impurity but also as temporary alloying element. This statement is based on the following. Hydrogen stabilizes high-temperature β-phase, leads to decrease in temperature of β→α transformation and extends (α + β )-phase field. The BCC β-phase exhibits lower strength and higher ductility in comparison with HCP α -phase. As a result, hydrogen improves hot workability of hard-to-deform titanium alloys. Hydrogen changes chemical composition of the phases, kinetics of phase transformations, and at low temperatures additional phase transformation (β→α + TiH 2 ) takes place, which is accompanied with noticeable change in volumes of phases. As a result, fine lamellar microstructure may be formed in hydrogenated titanium alloys after heat treatment. It was shown that controlled hydrogen alloying improves weldability and machinability of titanium alloys. After processing hydrogenated titanium preforms are subjected to vacuum annealing, and the hydrogen content decreases up to safe level. Hydrogen removal is accompanied with hydrides dissolution and β→α transformation that makes possible to control structure formation at this final step of treatment. Thus, reversible hydrogen alloying of titanium alloys allows to obtain novel microstructure with enhanced properties. The aim of the work was to study the effect of hydrogen on structure formation, namely: i) influence of hydrogen content on transformation of lamellar microstructure to globular one during deformation in (α+β)-phase field; ii) effect of dissolved hydrogen on dynamic recrystallization in single α- and β- phase regions; iii) influence of vacuum annealing temperature on microstructure development. The work was focused on the optimization of

  1. Fatigue crack growth behavior in niobium-hydrogen alloys

    International Nuclear Information System (INIS)

    Lin, M.C.C.; Salama, K.

    1997-01-01

    Near-threshold fatigue crack growth behavior has been investigated in niobium-hydrogen alloys. Compact tension specimens (CTS) with three hydrogen conditions are used: hydrogen-free, hydrogen in solid solution, and hydride alloy. The specimens are fatigued at a temperature of 296 K and load ratios of 0.05, 0.4, and 0.75. The results at load ratios of 0.05 and 0.4 show that the threshold stress intensity range (ΔK th ) decreases as hydrogen is added to niobium. It reaches a minimum at the critical hydrogen concentration (C cr ), where maximum embrittlement occurs. The critical hydrogen concentration is approximately equal to the solubility limit of hydrogen in niobium. As the hydrogen concentration exceeds C cr , ΔK th increases slowly as more hydrogen is added to the specimen. At load ratio 0.75, ΔK th decreases continuously as the hydrogen concentration is increased. The results provide evidence that two mechanisms are responsible for fatigue crack growth behavior in niobium-hydrogen alloys. First, embrittlement is retarded by hydride transformation--induced and plasticity-induced crack closures. Second, embrittlement is enhanced by the presence of hydrogen and hydride

  2. Study on hydrogen absorption/desorption properties of uranium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hiroshi; Yamaguchi, Kenji; Yamawaki, Michio [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.

    1996-10-01

    Hydrogen absorption/desorption properties of two U-Mn intermetallic compounds, U{sub 6}Mn and UMn{sub 2}, were investigated. U{sub 6}Mn absorbed hydrogen and the hydrogen desorption pressure of U{sub 6}Mn obtained from this experiment was higher than that of U, which was considered to be the effect of alloying, whereas UMn{sub 2} was not observed to absorb hydrogen up to 50 atm at room temperature. (author)

  3. Toward enhanced hydrogen generation from water using oxygen permeating LCF membranes

    KAUST Repository

    Wu, Xiao-Yu; Chang, Le; Uddi, Mruthunjaya; Kirchen, Patrick; Ghoniem, Ahmed F.

    2015-01-01

    and flow rates on the feed and sweep sides on the water thermolysis rate and oxygen flux. A single step reaction mechanism is proposed for surface reactions, and three-resistance permeation models are derived. Results show that water thermolysis

  4. Fractography of hydrogen-embrittled iron-chromium-nickel alloys

    International Nuclear Information System (INIS)

    Caskey, G.R. Jr.

    1980-01-01

    Tensile specimens of iron-chromium-nickel base alloys were broken in either a hydrogen environment or in air following thermal charging with hydrogen. Fracture surfaces were examined by scanning electron microscopy. Fracture morphology of hydrogen-embrittled specimens was characterized by: changed dimple size, twin-boundary parting, transgranular cleavage, and intergranular separation. The nature and extent of the fracture mode changes induced by hydrogen varied systematically with alloy composition and test temperature. Initial microstructure developed during deformation processing and heat treating had a secondary influence on fracture mode

  5. Alloying effect on the electronic structures of hydrogen storage compounds

    Energy Technology Data Exchange (ETDEWEB)

    Yukawa, H.; Moringa, M.; Takahashi, Y. [Nagoya Univ. (Japan). Dept. of Mater. Sci. and Eng.

    1997-05-20

    The electronic structures of hydrogenated LaNi{sub 5} containing various 3d transition elements were investigated by the DV-X{alpha} molecular orbital method. The hydrogen atom was found to form a strong chemical bond with the Ni rather than the La atoms. The alloying modified the chemical bond strengths between atoms in a small metal octahedron containing a hydrogen atom at the center, resulting in the change in the hydrogen absorption and desorption characteristics of LaNi{sub 5} with alloying. (orig.) 7 refs.

  6. Hydrogen as a New Alloying Element in Metals

    International Nuclear Information System (INIS)

    Shapovalov, Vladimir

    1999-01-01

    Hydrogen was regarded as a harmful impurity in many alloys and particularly in steels where it gives rise to a specific type of embrittlement and forms various discontinuities like flakes and blowholes. For this reason, the researcher efforts were mainly focused on eliminating hydrogen's negative impacts and explaining its uncommonly high diffusivity in condensed phases. Meanwhile, positive characteristics of hydrogen as an alloying element remained unknown for quite a long time. Initial reports in this field did not appear before the early 1970s. Data on new phase diagrams are given for metal-hydrogen systems where the metal may or may not form hydrides. Various kinds of hydrogen impact on structure formation in solidification, melting and solid-solid transformations are covered. Special attention is given to the most popular alloys based on iron, aluminum, copper, nickel, magnesium and titanium. Detailed is what is called gas-eutectic reaction resulting in a special type of gas-solid structure named gasarite. Properties and applications of gasars - gasaritic porous materials - are dealt with. Various versions of solid-state alloying with hydrogen are discussed that change physical properties and fabrication characteristics of metals. Details are given on a unique phenomenon of anomalous spontaneous deformation due to combination of hydrogen environment and polymorphic transformation. All currently known versions of alloying with hydrogen are categorized for both hydride-forming and non-hydrid forming metals

  7. Alloy development for irradiation performance. Quarterly progress report for period ending December 31, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1981-04-01

    Progress is reported in eight sections: analysis and evaluation studies, test matrices and test methods development, Path A Alloy Development (austenitic stainless steels), Path C Alloy Development (Ti and V alloys), Path D Alloy Development (Fe alloys), Path E Alloy Development (ferritic steels), irradiation experiments and materials inventory, and materials compatibility and hydrogen permeation studies. (DLC)

  8. Alloy development for irradiation performance. Quarterly progress report for period ending December 31, 1980

    International Nuclear Information System (INIS)

    1981-04-01

    Progress is reported in eight sections: analysis and evaluation studies, test matrices and test methods development, Path A Alloy Development (austenitic stainless steels), Path C Alloy Development (Ti and V alloys), Path D Alloy Development (Fe alloys), Path E Alloy Development (ferritic steels), irradiation experiments and materials inventory, and materials compatibility and hydrogen permeation studies

  9. Hydrogen uptake characteristics of mechanically alloyed Ti-V-Ni

    International Nuclear Information System (INIS)

    Cauceglia, Dorian; Hampton, Michael D.; Lomness, Janice K.; Slattery, Darlene K.; Resan, Mirna

    2006-01-01

    It has been well established that hydrogen will react directly and reversibly with a large number of metals and alloys to form metallic hydrides. Extensive research has been done over the years to improve properties of these hydrogen purification and recovery media and in developing new compounds for this purpose. In the present study, the hydrogen uptake characteristics of mechanically alloyed titanium-vanadium-nickel have been studied. Thermal and composition data were obtained for the Ti-V-Ni system prepared by mechanical alloying at a ball-to-powder mass ratio of 10:1. It was found that this material would absorb up to approximately 1.0 wt% hydrogen at near ambient temperature and ambient pressure of hydrogen

  10. Hydrogen charging, hydrogen content analysis and metallographic examination of hydride in zirconium alloys

    International Nuclear Information System (INIS)

    Singh, R.N.; Kishore, R.; Mukherjee, S.; Roychowdhury, S.; Srivastava, D.; Sinha, T.K.; De, P.K.; Banerjee, S.; Gopalan, B.; Kameswaran, R.; Sheelvantra, Smita S.

    2003-12-01

    Gaseous and electrolytic hydrogen charging techniques for introducing controlled amount of hydrogen in zirconium alloy is described. Zr-1wt%Nb fuel tube, zircaloy-2 pressure tube and Zr-2.5Nb pressure tube samples were charged with up to 1000 ppm of hydrogen by weight using one of the aforementioned methods. These hydrogen charged Zr-alloy samples were analyzed for estimating the total hydrogen content using inert gas fusion technique. Influence of sample surface preparation on the estimated hydrogen content is also discussed. In zirconium alloys, hydrogen in excess of the terminal solid solubility precipitates out as brittle hydride phase, which acquire platelet shaped morphology due to its accommodation in the matrix and can make the host matrix brittle. The F N number, which represents susceptibility of Zr-alloy tubes to hydride embrittlement was measured from the metallographs. The volume fraction of the hydride phase, platelet size, distribution, interplatelet spacing and orientation were examined metallographically using samples sliced along the radial-axial and radial-circumferential plane of the tubes. It was observed that hydride platelet length increases with increase in hydrogen content. Considering the metallographs generated by Materials Science Division as standard, metallographs prepared by the IAEA round robin participants for different hydrogen concentration was compared. It is felt that hydride micrographs can be used to estimate not only that approximate hydrogen concentration of the sample but also its size, distribution and orientation which significantly affect the susceptibility to hydride embrittlement of these alloys. (author)

  11. Fabrication characteristics and hydrogenation behavior of hydrogen storage alloys for sealed Ni-MH batteries

    Science.gov (United States)

    Kim, Ho-Sung; Kim, Jeon Min; Kim, Tae-Won; Oh, Ik-Hyun; Choi, Jeon; Park, Choong Nyeon

    2008-08-01

    Hydrogen storage alloys based on LmNi4.2Co0.2Mn0.3Al0.3 were fabricated to study the equilibrium hydrogen pressure and electrochemical performance. The surface morphology and structure of the alloys were analyzed by SEM and XRD, and then the hydrogenation behaviors of all alloys were evaluated by PCT and electrochemical half-cell. We studied the hydrogenation behavior of the Lm-based alloy with changes in composition elements such as Mn, Al, and Co and investigated the optimal design for Lm-based alloy in a sealed battery system. As a result of studying the hydrogenation characterization of alloys with the substitution elements, hydrogen storage alloys such as LmNi3.75Co0.15Mn0.5Al0.3 and LmNi3.5Co0.5Mn0.5Al0.5 were obtained to correspond with the characteristics of a sealed battery with a higher capacity, long life cycle, lower internal pressure, and lower battery cost. The capacity preservation rate of LmNi3.5Co0.5Mn0.5Al0.5 was greatly improved to 92.7% (255 mAh/g) at 60 cycles, indicating a low equilibrium hydrogen pressure of 0.03 atm in PCT devices.

  12. Hydrogen permeation and corrosion behavior of high strength steel MCM 430 in cyclic wet-dry SO2 environment

    International Nuclear Information System (INIS)

    Nishimura, Rokuro; Shiraishi, Daisuke; Maeda, Yasuaki

    2004-01-01

    Hydrogen permeation caused by corrosion under a cyclic wet (2 h)-dry (10 h) SO 2 condition was investigated for a high strength steel of MCM 430 by using an electrochemical technique in addition to the corrosion behavior obtained from weight loss measurement and the determination of corrosion products by using X-ray diffraction method. The hydrogen content converted from hydrogen permeation current density was observed in both wet and dry periods. The origin of proton was estimated to be from (1) the hydrolysis of ferrous ions, (2) the oxidation of ferrous ions and ferrous hydroxide, and (3) hydrolysis of SO 2 and formation of FeSO 4 , but not from the dissociation of H 2 O. With respect to the determination of the corrosion products consisting of inner (adherent) and outer (not adherent) layers, the outer layer is composed of α-FeOOH, amorphous phase and γ-FeOOH, where α-FeOOH increases with the increase in the wet-dry cycle, and amorphous phase shows the reverse trend. The corrosion product in the inner layer is mainly Fe 3 O 4 with them. On the basis of the results obtained, the role of the dry or wet period, the effect of SO 2 and the corrosion process during the cyclic wet-dry periods were discussed

  13. Hydrogen release from vanadium alloy V-4Cr-4Ti

    International Nuclear Information System (INIS)

    Klepikov, A.Kh; Kulsartov, T.V.; Chikhray, E.V.; Romanenko, O.G.; Tazhibaeva, I.L.; Shestakov, V.P.

    1999-01-01

    The experiments on hydrogen loading of vanadium alloy with the following thermodesorption spectroscopy (TDS) measurements were carried out with the sample of the V-4Cr-4Ti vanadium alloy (Russia production). Hydrogen solubility was calculated from experimental TDS curves, obtained after equilibrium loading of the sample at the temperatures 673, 773, 873, 973, and 1073 K. The range of loading pressures was 10-100 Pa. The experiments carried out had an objective to determine the regimes (loading time, temperatures and pressures) for the experiment on in-pile loading of the vanadium alloy. (author)

  14. Internal hydrogen embrittlement of gamma-stabilized uranium alloys

    International Nuclear Information System (INIS)

    Powell, G.L.; Koger, J.W.; Bennett, R.K.; Williamson, A.L.; Hemperly, V.C.

    1976-01-01

    Relationships between the tensile ductility and fracture characteristics of as-quenched, gamma-stabilized uranium alloys (uranium--10 wt percent molybdenum, uranium--8.5 wt percent niobium, uranium--10 wt percent niobium, and uranium--7.5 wt percent niobium--2.5 wt percent zirconium), the hydrogen content of the tensile specimens, and the hydrogen gas pressure during the annealing at 850 0 C of the tensile test blanks prior to quenching were established. For these alloys, the tensile ductility decreases only slightly with increasing hydrogen content up to a critical hydrogen concentration above which the tensile ductility drops to nearly zero. The only alloy not displaying this sharp drop in tensile ductility was U--7.5 Nb--2.5 Zr, probably because sufficiently high hydrogen contents could not be achieved under our experimental arrangements. The critical hydrogen content for ductility loss increased with increasing hydrogen solubility in the alloy. Fracture surfaces produced by internal hydrogen embrittlement do not resemble those produced by stress corrosion cracking (SCC) in aqueous environments containing chloride ions. 8 figs

  15. Experimental measurements of the permeation of hydrogen isotopes in lithium filled niobium cells

    International Nuclear Information System (INIS)

    Goodall, D.H.J.; McCracken, G.M.; Austin, G.E.

    1976-01-01

    Lithium filled niobium cells have been heated in vacua at temperatures in the range 300 to 900 0 C. By measuring the flow of deuterium into the cell it has been possible to make estimates of the rate of permeation of deuterium in the niobium wall. After initial fast diffusion into the capsule the rate of permeation becomes very much slower than that determined by diffusion in the bulk niobium indicating that a second, slower, rate process is involved. Measurements of the rate of deuterium permeation out of the cell have been made for a number of different cell geometries and a range of temperatures. The results indicate that the slow rate process, which is dominant at low concentrations, is the desorption step from the metal to the gas phase

  16. Ageing of Mg-Ni-H hydrogen storage alloys

    Czech Academy of Sciences Publication Activity Database

    Čermák, Jiří; Král, Lubomír

    2012-01-01

    Roč. 37, OCT (2012), s. 14257-14264 ISSN 0360-3199 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068; GA ČR GA106/09/0814; GA ČR(CZ) GAP108/11/0148 Institutional research plan: CEZ:AV0Z20410507 Keywords : Magnesium alloys * Hydrogen desorption * Hydrogen storage * Hydrogen-storage materials * Ageing Subject RIV: JG - Metallurgy Impact factor: 3.548, year: 2012

  17. Research on hydrogen storage alloys and their uses

    International Nuclear Information System (INIS)

    Alcock, C.B.; Hewitt, J.S.; Khatamian, D.; Manchester, F.D.; McLean, A.; Ward, C.A.; Weatherly, G.C.

    1984-01-01

    A brief account is given of the work being done by members of the Centre on the development of hydrogen storage alloys having useful, reliable, and predictable, performance characteristics. Metals and alloys which have been studied, in one or more aspects, so far, include FeTi, and also FeTi with small added amounts of C, Mn, Al and Mischmetal. Experimental work on the FeTi family of alloys has been concentrated on surface structure and surface behaviour and the importance of these for determining successful activation for hydrogen absorption. As a part of development work on control devices responding to temperature changes through hydrogen desorption, experiments have been performed on hydrides of Nb, La-Ni-Al and Ca-Ni. Some theoretical modelling on kinetics of hydrogen absorption into metals has also been done

  18. Hydrogen formation in metals and alloys during fusion reactor operation

    International Nuclear Information System (INIS)

    Zimin, S.; Takatsu, Hideyuki; Mori, Seiji

    1994-08-01

    The results of neutron transport calculations of the hydrogen formation based on the JENDL gas-production cross section file are discussed for some metals and alloys, namely 51 V, Cr, Fe, Ni, Mo, austenitic stainless steel (Ti modified 316SS:PCA), ferritic steel (Fe-8Cr-2W:F82H) and the vanadium-base alloy (V-5Cr-5Ti). Impact of the steel fraction in steel/water homogeneous blanket/shield compositions on the hydrogen formation rate in above-mentioned metals and alloys is discussed both for the hydrogen formation in the first wall and the blanket/shield components. The results obtained for the first wall are compared with those for the helium formation obtained at JAERI by the same calculational conditions. Hydrogen formation rates at the first wall having 51 V, Cr, Fe, Ni and Mo are larger than those of helium by 3-8 times. (author)

  19. Permeation, diffusion and dissolution of hydrogen isotopes, methane and inert gases through/in a tetrafluoroethylene film

    International Nuclear Information System (INIS)

    Matsuyama, M.; Miyake, H.; Ashida, K.; Watanabe, K.

    1982-01-01

    Tetrafluoroethylene (TFE) is widely used for conventional tritium handling systems such as vacuum seals, tubing and so on. We measured the permeation of the three hydrogen isotopes, methane and the inert gases through a TFE film at room temperature by means of the time-lag method in order to establish the physicochemical properties which determine the solubility and diffusivity of those gases. It was found that the diffusion constant of the inert gases changed exponentially with the heat of vaporization and the solubility was an exponential function of the Lennard-Jones force constant of the gases. On the other hand, hydrogen isotopes and methane deviated from these relations. It is concluded that chemical interactions between the solute and the solvent play an important role for the dissolution and the diffusion of these gases in TFE. (orig.)

  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. Hydrogenations of alloys and intermetallic compounds of magnesium

    International Nuclear Information System (INIS)

    Gavra, Z.

    1981-08-01

    A kinetic and thermodynamic study of the hydrogenation of alloys and intermetallic compounds of magnesium is presented. It was established that the addition of elements of the IIIA group (Al, Ga, In) to magnesium catalyses its hydrogenation. This is explained by the mechanism of diffusion of magnesium cation vacancies. The hydride Mg 2 NiH 4 was characterized by thermal analysis, x-ray diffraction and NMR measurements. The possibility of forming pseudo-binary compounds of Mg 2 Ni by the substitution of nickel or magnesium was examined. The hydrogenation of the inter-metallic compounds of the Mg-Al system was investigated. It was found that the addition of indium and nickel affected the hydrogenation kinetics. A preliminary study of the hydrogenation of various binary and ternary alloys of magnesium was carried out. (Author)

  2. Hydrogen and deuterium transport and inventory parameters through W and W-alloys for fusion reactor applications

    Science.gov (United States)

    Benamati, G.; Serra, E.; Wu, C. H.

    2000-12-01

    The aim of this work is to measure the hydrogen/deuterium transport and inventory parameters in relevant structural and/or armour materials for the International Thermonuclear Experimental Reactor (ITER) divertor such as W and W-alloys. The W-alloys: W, W + 1% La 2O 3 and W + 5% Re have been investigated. The materials were supplied from the Metallwerk Plansee GmbH (Austria). Measurements were conducted using a time-dependent permeation method over the temperature range 673-873 K with hydrogen and deuterium pressures in the range 10-100 kPa (100-1000 mbar). The samples were also characterized using optical microscopy, SEM and energy dispersive spectroscopy (EDS) in order to investigate the composition, microstructure and morphology of the surfaces and cross-sections through the samples.

  3. The diffusion behaviour of hydrogen in a low alloyed carbon steel with respect to the deformation level and to the passivation process in alkaline solutions

    International Nuclear Information System (INIS)

    Juilfs, G.G.

    2001-01-01

    The diffusion behaviour of hydrogen in a low alloyed carbon steel with respect to the deformation level and to the passivation process in alkaline solutions. The influence of plastic strain on the diffusion behaviour of hydrogen in a low alloyed structural steel (FeE 690T) was investigated using the electrochemical permeation technique. The plastic deformation was introduced either by cold rolling or by tensile straining. Specially prepared C(T)-specimen enabled the direct determination of the diffusion coefficient in the highly deformed region ahead of a blunting crack. It was shown, that the apparent diffusion coefficient depends on the plastic strain and on the overall hydrogen concentration, whereas the maximum hydrogen flux remained almost unchanged. These observations are interpreted in terms of variations in the dislocation density, which act as 'sinks' for the diffusable hydrogen atoms. The results are compared with model calculations, that describe the hydrogen transport as a function of the trap density. The comparison of the numerical simulation and the experimental data shows a good agreement over the whole range of plastic strain levels, leading to a trap density of 6.1.10 19 /d 3 . Together with the results of a previous study on the fracture toughness of FeE 690T in the presence of hydrogen the permeation data obtained in this work suggest that the observed influence of deformation rates on the fracture mechanism can be attributed to the reduced mobility of hydrogen atoms in the plastic zone. The assumption that the hydrogen transport during monotonic straining is controlled by diffusion was confirmed by investigations concerning the formation of surface films. Using a potentiodynamic method (cyclovoltammetry) a characterisation of the surface reactions involved in permeation experiments was performed. It was shown that the nature of the passive layers forming on the surface depends on the applied potential, affecting mainly the hydrogen absorption

  4. Development of tantalum–zirconium alloy for hydrogen purification

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sanjay, E-mail: sanjay.barc@gmail.com [Fusion Reactor Materials Section, MG, BARC, Mumbai 85 (India); IAMR, Hiroshima University, Higashihiroshima 739-8530 (Japan); Singh, Anamika [GSASM Hiroshima University, Higashihiroshima 739-8530 (Japan); Jain, Uttam; Dey, Gautam Kumar [Fusion Reactor Materials Section, MG, BARC, Mumbai 85 (India)

    2016-11-01

    Highlights: • Terminal solid solubility of Ta increases with Zr addition. • Increase in lattice parameters of Ta due to Zr addition may be the possible reason. • Enhance H solubility could also be explained on the change in e-DOS of Ta–Zr alloys. • Ta–Zr alloys could be possible combination for hydrogen purification membrane. - Abstract: Terminal solid solubility of hydrogen in Ta–Zr alloys has been studied in connection with the development of tantalum based metallic membrane for hydrogen/tritium purification. The alloys were prepared by vacuum arc melting technique and subsequently cold rolled to 0.2 mm thickness. The terminal solid solubility of hydrogen in these cold rolled samples was investigated in a modified Sieverts apparatus. The terminal solid solubility of hydrogen was marginally increased with zirconium content. The change in the lattices parameter of tantalum upon zirconium addition and the higher affinity of zirconium for hydrogen as compared to tantalum could be the possible reasons.

  5. Hydrogen permeation through steel coated with erbium oxide by sol-gel method

    International Nuclear Information System (INIS)

    Yao Zhenyu; Suzuki, Akihiro; Levchuk, Denis; Chikada, Takumi; Tanaka, Teruya; Muroga, Takeo; Terai, Takayuki

    2009-01-01

    Er 2 O 3 coating is formed on austenitic stainless steel 316ss by sol-gel method. The results showed good crystallization of coating by baking in high purity flowing-argon at 973 K, and indicated that a little oxygen in baking atmosphere is necessary to crystallization of coating. The best baking temperature could be thought as 973 K, to get good crystallization of coating and avoid strong oxidation of steel substrate. The deuterium permeation test was performed for coated and bare 316ss, to evaluate the property of Er 2 O 3 sol-gel coating as a potential tritium permeation barrier. In this study, the deuterium permeability of coated 316ss is about 1-2 orders of magnitude lower than that of bare 316ss, and is about 2-3 orders of magnitude than the referred data of bare Eurofer97 and F82H martensitic steel.

  6. Recycling, inventory and permeation of hydrogen isotopes and helium in the first wall of a thermonuclear fusion reactor

    International Nuclear Information System (INIS)

    Gervasini, G.; Reiter, F.

    1989-01-01

    The work was divided into three parts. The first part, which is theoretical, examines the behaviour of hydrogen in metals. After an introduction on the presence of hydrogen isotopes in fusion reactors, the main phenomena connected with hydrogen-metal interaction are summarised: solubility, diffusivity and trapping in material defects. The metal temperature is highlighted as the main parameter in the description of the phenomena. The second part of the work, also theoretical, concerns the interaction between helium and metals. We have tried as much as possible to show analogies and differences in the comparisons of the behaviour of hydrogen. The main types of damage caused by helium in metallic structures, which are the most important consequence of helium-metal interaction, were summarised. The characteristics of helium were treated in greater depth than those of hydrogen, because the latter are very well known. Also, there is a vast literature on the hydrogen-metal interaction. In the third and last part of the work a model was identified which allows the simulation of the evolution of a system formed from a metal in which hydrogen and helium isotopes have been introduced. A system of algebraic-differential equations was used to study the temporal evolution of the concentrations, the recycling, the inventory and the permeation of tritium and helium considering that these atoms diffuse in the metallic lattice and remain trapped in the vacancies created inside the metal by the bombardment of the neutrons from the fusion reactions. For the numerical simulation a series of data intended to represent the situation inside a thermonuclear reactor as precisely as possible were used for the numerical simulation. Analysis of the system was preceded by the analytical resolution of the steady state equations so that they could be compared with the simulation results

  7. Hysteresis-free nanoplasmonic pd-au alloy hydrogen sensors

    DEFF Research Database (Denmark)

    Wadell, Carl; Nugroho, Ferry Anggoro Ardy; Lidström, Emil

    2015-01-01

    hydrogen sensors. By increasing the amount of Au in the alloy nanoparticles up to 25 atom %, we are able to suppress the hysteresis between hydrogen absorption and desorption, thereby increasing the sensor accuracy to below 5% throughout the investigated 1 mbar to 1 bar hydrogen pressure range. Furthermore......, we observe an 8-fold absolute sensitivity enhancement at low hydrogen pressures compared to sensors made of pure Pd, and an improved sensor response time to below one second within the 0-40 mbar pressure range, that is, below the flammability limit, by engineering the nanoparticle size....

  8. Benzene adsorption and hydrogenation on Pd-Ru alloy by pulse chromatography

    International Nuclear Information System (INIS)

    Dobrokhotov, V.G.; Pavlova, L.F.; Gryaznov, V.M.

    1983-01-01

    Pulse chromatography has been applied to investigate benzene adsorption and hydrogenation on the Walls of a capillary of the Pd-6% Ru alloy at different hydrogen contents in the alloy and various methods of hydrogen supply: as a mixture with benzene vapors or by diffusion through the walls of the capillary. It is stated that reversible adsorption of benzene vapors on the Pd-6% Ru alloy at 303 K under the conditions of the β-phase existence in the alloy-hydrogen system does not change whereas in the region of the α-phase existence it slightly increases with a growth of hydrogen pressure. Strongly adsorbed benzene occupies approximately 7% of the surface. Only strongly adsorbed benzene is hydrogenated on the α-phase of the alloy-hydrogen system. Hydrogen supply to the hydrogenation zone by diffusion throUgh the alloy results in supersaturation of the surface active in the reaction of benzene hydrogenation with a chemisorbed hydrogen form

  9. Oxygen- and hydrogen-permeation measurements on-mixed conducting SrFeCo{sub 0.5}O{sub y} ceramic membrane material

    Energy Technology Data Exchange (ETDEWEB)

    Serra, E.; Casagrande, E.; La Barbera, A. [ENEA UTS MAT, CR Casaccia, 00060 S.M. di Galeria, Roma (Italy); Alvisi, M. [ENEA UTS MAT, CR Brindisi, 72100 Brindisi (Italy); Bezzi, G.; Mingazzini, C. [ENEA UTS MAT, CR Faenza, 48018 Faenza (Italy)

    2008-02-15

    The SrFeCo{sub 0.5}O{sub y} system combines high electronic/ionic conductivity with appreciable oxygen permeability at elevated temperatures. This system has potential use in high-temperature electrochemical applications such as solid oxide fuel cells, batteries, sensors, and oxygen separation membranes. Dense ceramic membranes of SrFeCo{sub 0.5}O{sub y} are prepared by pressing a ceramic powder prepared by using a sol-gel combustion technique. Oxygen and hydrogen permeation at high temperature on this material are studied. Measurements are conducted using a time-dependent permeation method at the temperature in the range of 1073-1273 K with oxygen- and hydrogen-driving pressures in the range (3 x 10{sup 2})-(1 x 10{sup 5}) Pa (300-1000 mbar). The maximum oxygen-permeated flux at 1273 K is 6.5 x 10{sup -3} mol m{sup -2} s{sup -1}. The activation energies for the O{sub 2}-permeation fluxes and diffusivities are 240 and 194 kJ/mol, respectively. Due to the high fragility, the high temperature for the measurements and the high oxygen permeation through such material, a special membrane holder, and compression sealing system have been designed and realized for the permeation apparatus. (author)

  10. Possible origin and roles of nano-porosity in ZrO2 scales for hydrogen pick-up in Zr alloys

    Science.gov (United States)

    Lindgren, Mikaela; Geers, Christine; Panas, Itai

    2017-08-01

    A mechanistic understanding of Wagnerian build-up and subsequent non-Wagnerian break-down of barrier oxide upon oxidation of zirconium alloys by water is reiterated. Hydrogen assisted build-up of nano-porosity is addressed. Growth of sub-nanometer wide stalactitic pores owing to increasing aggregation of neutral oxygen vacancies offering a means to permeate hydrogen into the alloy is explored by density functional theory. The Wagnerian channel utilizes charge separation allowing charged oxygen vacancies and electrons to move separately from nominal anode to nominal cathode. This process becomes increasingly controlled by the charging of the barrier oxide resulting in sub-parabolic rate law for oxide growth. The break-down of the barrier oxide is understood to be preceded by avalanching hydrogen pick-up in the alloy. Pore mediated diffusion allows water to effectively short circuit the barrier oxide.

  11. Determination of hydrogen permeation using metallic sensors of construction similar to bimetallic thermocouples; Determinacao de permeacao de hidrogenio utilizando sensores metalicos de construcao similar a termopares bimetalicos

    Energy Technology Data Exchange (ETDEWEB)

    Maul, Alexandre M. [Ministerio de Ciencia e Tecnologia (MCT), Brasilia, DF (Brazil). Programa de Pos-graduacao em Engenharia e Processos (PIPE- PRH-24/ANP); Ponte, Haroldo A. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil); Correa, Luiz A. [Metaldata Tecnologia de Materiais, Curitiba, PR (Brazil)] (in Memoriam)

    2004-07-01

    Crude oils range in consistency from water to tar-like solids, and in color from clear to black. An average crude oil contains about 84 percent carbon, 14 percent hydrogen, 1 to 3 percent sulfur, and less than 1 percent each of nitrogen, oxygen, metals, and salts. Crude oils are generally classified as paraffinic, naphthenic, or aromatic based on the predominant proportion of similar hydrocarbon molecules. Refinery crude base stocks usually consist of mixtures of two or more different crude oils. Many corrosive processes found in machines, equipment and pipes used in the petroleum industry are directly influenced by hydrogen. The structural damages are caused by hydrogen inclusion in metallic structures, generated by acid media that contain free protons (H{sup +}), by chemical processes that lead to the protons formation, by formation of atomic hydrogen (H0) or even by adsorbed gas hydrogen (H2). The structural damages are varied: hydrogen induced cracking (HIC), blistering, stress corrosion cracking (SSC), stress oriented hydrogen induced cracking (SOHIC). The main problem found in practice is how to detect, in a safe, fast and economically viable way, the formation of hydrogen close to a surface subjected to hydrogen permeation. Within this work, we built a cell for hydrogen generation/permeation to study and evaluate a new hydrogen sensor. This new sensor is composed of two parts, each one build with a couple of dissimilar materials, being a sensor couple, for hydrogen flux measurement, and a reference couple, for temperature corrections. In this sensor, the changes in some physical properties are related with the flow of permeated hydrogen. The results using a prototype model showed good agreement with a traditional Devanathan-Stachurski sensor. (author)

  12. Experimental study on uranium alloys for hydrogen storage

    International Nuclear Information System (INIS)

    Deaconu, M.; Meleg, T.; Dinu, A.; Mihalache, M.; Ciuca, I.; Abrudeanu, M.

    2013-01-01

    The heaviest isotope of hydrogen is one of critically important elements in the field of fusion reactor technology. Conventionally, uranium metal is used for the storage of heavier isotopes of hydrogen (D and T). Under appropriate conditions, uranium absorbs hydrogen to form a stable UH 3 compound when exposed to molecular hydrogen at the temperature range of 300-500 O C at varied operating pressure below one atmosphere. However, hydriding-dehydriding on pure uranium disintegrates the specimen into fine powder. The powder is highly pyrophoric and has low heat conductivity, which makes it difficult to control the temperature, and has a high possibility of contamination Due to the powdering effect as hydrogen in uranium, alloying uranium with other metal looks promising for the use of hydrogen storage materials. This paper has the aim to study the hydriding properties of uranium alloys, including U-Ti U-Mo and U-Ni. The uranium alloys specimens were prepared by melting the constituent elements by means of simultaneous measurements of thermo-gravimetric and differential thermal analyses (TGA-DTA) and studied in as cast condition as hydrogen storage materials. Then samples were thermally treated under constant flow of hydrogen, at various temperatures between 573-973 0 K. The structural and absorption properties of the products obtained were examined by thermo-gravimetric analysis (TG), X-ray diffraction (XRD) and scanning electron microscopy (SEM). They slowly reacted with hydrogen to form the ternary hydride and the hydrogenated samples mainly consisted of the pursued ternary hydride bat contained also U or UO 2 and some transient phase. (authors)

  13. Gas phase hydrogen permeation through ferritic iron, austenitic stainless steel and neutron irradiated austenitic stainless steel from near 3000K to 8730K

    International Nuclear Information System (INIS)

    Quick, N.R.

    1976-01-01

    Hydrogen permeation through iron was studied over the temperature range 300 to 873 0 K by an ultra high vacuum, monopole gas analyzer technique. Hydrogen gas input pressures were varied from 0.0043 to 0.62 atm and membrane thicknesses from 0.0165 to 0.243 cm. Volume diffusion control of the permeation process was demonstrated by the pressure and membrane thickness dependence of the steady state flux. The permeation coefficient, with an activation enthalpy found to be 8.1 +-.4 kcal/mole, was independent of both gas pressure and membrane thickness. At temperatures below approximately 600 0 K, the effective diffusivity increased with both increasing hydrogen gas pressure and increasing membrane thickness. The transition temperature from classical to anomalous behavior decreases with increasing thickness. Apparent activation enthalpies for diffusion were found to range from 1.6 to 8.2 kcal/mole with the lower values associated with thicker membranes. The permeation coefficient activation enthalpy was found to be 13.1 +- .4 kcal/mole while that for diffusivity was found to be 11.2 +- .45 kcal/mole. However, samples neutron irradiated at a fluence of 10 17 n/cm 2 showed anomalous effects in that both effective diffusivity and permeation were reduced in value

  14. Compensation effect in H 2 permeation kinetics of PdAg membranes

    KAUST Repository

    Zeng, Gaofeng

    2012-08-30

    Knowledge about the (inter)dependence of permeation kinetic parameters on the stoichiometry of H 2-selective alloys is still rudimentary, although uncovering the underlying systematic correlations will greatly facilitate current efforts into the design of novel high-performance H 2 separation membranes. Permeation measurements with carefully engineered, 2-7 μm thick supported Pd 100-xAg x membranes reveal that the activation energy and pre-exponential factor of H 2 permeation laws vary systematically with alloy composition, and both kinetic parameters are strongly correlated for x ≤ 50. We show that this permeation kinetic compensation effect corresponds well with similar correlations in the hydrogen solution thermodynamics and diffusion kinetics of PdAg alloys that govern H 2 permeation rates. This effect enables the consistent description of permeation characteristics over wide temperature and alloy stoichiometry ranges, whereas hydrogen solution thermodynamics may play a role, too, as a yet unrecognized source of kinetic compensation in, for example, H 2-involving reactions over metal catalysts or hydrogenation/ dehydrogenation of hydrogen storage materials. © 2012 American Chemical Society.

  15. Tritium permeation in stainless-steel structures exposed to plasma ions

    International Nuclear Information System (INIS)

    Anderl, R.A.; Holland, D.F.; Struttmann, D.A.; Longhurst, G.R.; Merrill, B.J.

    1985-01-01

    This paper presents a comparison of the hydrogen permeation properties of the austenitic primary candidate alloy, PCA, and of the advanced ferritic alloy, HT-9. The comparison is based on experimental measurements of the permeation and reemission of deuterium from specimens undergoing implantation with 3-keV, D 3 + ions produced by an accelerator. Characterization of the specimen surface facing the ion beam is provided by secondary ion mass spectrometer (SIMS) analysis of the species sputtered from the surface during the implantation. Recombination and diffusivity data for PCA and HT-9 were derived from an analysis in which model calculations were applied to the reemission and permeation measurements

  16. Study of hydrogen isotopes super permeation through vanadium membrane on 'Prometheus' setup

    International Nuclear Information System (INIS)

    Musyaev, R. K.; Yukhimchuk, A. A.; Lebedev, B. S.; Busnyuk, A. O.; Notkin, M. E.; Samartsev, A. A.; Livshits, A. I.

    2008-01-01

    To develop the membrane pumping technology by means of superpermeable membranes at RFNC-VNIIEF in the 'Prometheus' setup, the experiments on superpermeation of hydrogen isotopes through metal membranes were carried out. The experimental results on superpermeation of thermal atoms of hydrogen isotopes including tritium through a cylindrical vanadium membrane are presented. The possibility of effective pumping, compression and recuperation of hydrogen isotopes by means of superpermeable membrane was demonstrated. The evaluation of membrane pumping rates and asymmetry degree of pure vanadium membrane was given. The work was performed under the ISTC-2854 project. (authors)

  17. Modeling of roughness effect on hydrogen permeation in a low carbon steel

    OpenAIRE

    Carreño, J. A.; Uribe, I.; Carrillo, J. C.

    2003-01-01

    A model is presented to evaluate the effect of the roughness and the profile of concentration of hydrogen in a low carbon steel. The model takes advantage of the Fick's Second Law, to predict the transport of hydrogen in the steel. The problem is treated as a variational one and its space solution is made numerically by means of the Finite Elements Method, while the temporal equation is solved via the Finite Differences Method, in order to determine the concentration profiles of Hydrogen in t...

  18. Property changes of some hydrogen storage alloys upon hydrogen absorption-desorption cycling

    International Nuclear Information System (INIS)

    Park, C.N.; Cho, S.W.; Choi, J.

    2005-01-01

    Hydrogen absorption-desorption cycling induced by pressure change in a closed system were carried out with LaNi 5 , La 0.7 Ce 0.3 Ni 4 Cu and TiFe 0.9 Ni 0.1 alloys. PC isotherms measured during the cycling showed some changes in hydrogen storage capacity, plateau pressure and hysteresis of the alloys. The half capacity life of LaNi 5 alloy can be projected as 70,000 cycles for room temperature pressure cycling. When La 0.7 Ce 0.3 Ni 4 Cu alloy was pressure cycled both of the plateau pressures were decreased significantly and continuously. TiFe 0.9 Ni 0.1 alloy showed a good resistance to cyclic degradation. Heat treatments of the degraded alloys under 1 atm of hydrogen gas recovered most of the hydrogen storage properties to the initial level even though they were degraded again more rapidly upon subsequent cycling. (orig.)

  19. Hydrogen storage alloy for a battery; Denchiyo suiso kyuzo gokin

    Energy Technology Data Exchange (ETDEWEB)

    Saito, N.; Takahashi, M.; Sasai, T. [Japan Metals and Chemicals Co. Ltd., Tsukuba (Japan)

    1997-11-18

    Cobalt contained in a hydrogen storage alloy has an effect to improve a cycle life, but it gives a problem of inferior discharge characteristics. Moreover, cobalt is a rather expensive constituent and therefore, it is desirable to suppress its use as far as possible. This invention aims to present a hydrogen storage alloy with a long service life and high discharge characteristics for a negative electrode of a hydrogen battery without containing a large amount of cobalt. The hydrogen storage alloy of this invention has a composition of a general formula: RNi(a)Co(b)Al(c)Mn(d)Fe(e), where R is a mixture of rare earth elements and La content in this alloy is 25 to 70wt%, 3.7{<=}a{<=}4.0, 0.1{<=}b{<=}0.4, 0.20{<=}c{<=}0.4, 0.30{<=}d{<=}0.45, 0.2{<=}e{<=}0.4, 0.5{<=}b+e{<=}0.7 and 5.0{<=}a+b+c+d+e{<=}5.1. 1 tab.

  20. High temperature cathodic charging of hydrogen in zirconium alloys and iron and nickel base alloys

    International Nuclear Information System (INIS)

    John, J.T.; De, P.K.; Gadiyar, H.S.

    1990-01-01

    These investigations lead to the development of a new technique for charging hydrogen into metals and alloys. In this technique a mixture of sulfates and bisulfates of sodium and potassium is kept saturated with water at 250-300degC in an open pyrex glass beaker and electrolysed using platinum anode and the material to be charged as the cathode. Most of the studies were carried out on Zr alloys. It is shown that because of the high hydrogen flux available at the surface and the high diffusivity of hydrogen in metals at these temperatures the materials pick up hydrogen faster and more uniformly than the conventional electrolytic charging at room temperature and high temperature autoclaving in LiOH solutions. Chemical analysis, metallographic examination and XRD studies confirm this. This technique has been used to charge hydrogen into many iron and nickel base austentic alloys, which are very resistant to hydrogen pick up and to H-embrittlement. Since this involved a novel method of electrolysing water, the hydrogen/deuterium isotopic ratio has been studied. At this temperatures the D/H ratio in the evolved hydrogen gas was found to be closer to the value in the liquid water, which means a smaller separation factor. This confirm the earlier observation that separation factor decreases with increase of temperature. (author). 16 refs., 21 fi gs., 6 tabs

  1. Ternary alloy nanocatalysts for hydrogen evolution reaction

    Indian Academy of Sciences (India)

    Generation of hydrogen through water splitting is an impor- tant area of research. ... Splitting of water using electricity makes this reaction feasible, but requires a catalyst to overcome .... The obtained product was dried in air and heated at 700.

  2. Fatigue of vanadium--hydrogen alloys

    International Nuclear Information System (INIS)

    Lee, K.S.; Stoloff, N.S.

    1975-01-01

    Hydrogen contents near and above the room temperature solubility limit increase the high cycle fatigue life but decrease low cycle life of polycrystalline vanadium. Changes in endurance limit with hydrides may be a consequence of decreased cyclic strain hardening coefficient, n'. 132 ppM hydrogen in solution has only a slightly beneficial effect on stress controlled fatigue life and essentially no effect on low cycle fatigue life. Unalloyed vanadium exhibits profuse striations, while hydrides produce cleavage cracks in fatigued samples. 10 fig

  3. Lunar-derived titanium alloys for hydrogen storage

    Science.gov (United States)

    Love, S.; Hertzberg, A.; Woodcock, G.

    1992-01-01

    Hydrogen gas, which plays an important role in many projected lunar power systems and industrial processes, can be stored in metallic titanium and in certain titanium alloys as an interstitial hydride compound. Storing and retrieving hydrogen with titanium-iron alloy requires substantially less energy investment than storage by liquefaction. Metal hydride storage systems can be designed to operate at a wide range of temperatures and pressures. A few such systems have been developed for terrestrial applications. A drawback of metal hydride storage for lunar applications is the system's large mass per mole of hydrogen stored, which rules out transporting it from earth. The transportation problem can be solved by using native lunar materials, which are rich in titanium and iron.

  4. Effective hydrogen diffusion coefficient for solidifying aluminium alloys

    International Nuclear Information System (INIS)

    Felberbaum, M.; Landry-Desy, E.; Weber, L.; Rappaz, M.

    2011-01-01

    An effective hydrogen diffusion coefficient has been calculated for two solidifying Al - 4.5 wt.% Cu and Al - 10 wt.% Cu alloys as a function of the volume fraction of solid. For this purpose, in situ X-ray tomography was performed on these alloys. For each volume fraction of solid between 0.6 and 0.9, a representative volume element of the microstructure was extracted. Solid and liquid voxels were assimilated to solid and liquid nodes in order to solve the hydrogen diffusion equation based on the chemical potential and using a finite volume formulation. An effective hydrogen diffusion coefficient based on the volume fraction of solid only could be deduced from the results of the numerical model at steady state. The results are compared with various effective medium theories.

  5. Hydrogen-plasticity in the austenitic alloys; Interactions hydrogene-plasticite dans les alliages austenitiques

    Energy Technology Data Exchange (ETDEWEB)

    De lafosse, D. [Ecole Nationale Superieure des Mines, Lab. PECM-UMR CNRS 5146, 42 - Saint-Etienne (France)

    2007-07-01

    This presentation deals with the hydrogen effects under stresses corrosion, in austenitic alloys. The objective is to validate and characterize experimentally the potential and the limits of an approach based on an elastic theory of crystal defects. The first part is devoted to the macroscopic characterization of dynamic hydrogen-dislocations interactions by aging tests. then the hydrogen influence on the plasticity is evaluated, using analytical classic models of the elastic theory of dislocations. The hydrogen influence on the flow stress of bcc materials is analyzed experimentally with model materials. (A.L.B.)

  6. Ternary alloy nanocatalysts for hydrogen evolution reaction

    Indian Academy of Sciences (India)

    CuFeNi (A1), CuFe2Ni (A2) and CuFeNi2 (A3) were successfully synthesized using microemulsion. It is to be noted that synthesis of nanocrystallineternary alloys with precise composition is a big challenge which can be overcome by choosing an appropriate microemulsion system. High electrocatalytic activity towards HER ...

  7. Hydrogen embrittlement considerations in niobium-base alloys for application in the ITER divertor

    International Nuclear Information System (INIS)

    Peterson, D.T.; Hull, A.B.; Loomis, B.A.

    1991-01-01

    The ITER divertor will be subjected to hydrogen from aqueous corrosion by the coolant and by transfer from the plasma. Global hydrogen concentrations are one factor in assessing hydrogen embrittlement but local concentrations affected by source fluxes and thermotransport in thermal gradients are more important considerations. Global hydrogen concentrations is some corrosion- tested alloys will be presented and interpreted. The degradation of mechanical properties of Nb-base alloys due to hydrogen is a complex function of temperature, hydrogen concentration, stresses and alloy composition. The known tendencies for embrittlement and hydride formation in Nb alloys are reviewed

  8. Interaction of hydrogen with an Mg-Al alloy

    International Nuclear Information System (INIS)

    Andreasen, A.; Sorensen, M.B.; Burkarl, R.; Moller, B.; Molenbroek, A.M.; Pedersen, A.S.; Andreasen, J.W.; Nielsen, M.M.; Jensen, T.R.

    2005-01-01

    The interaction of hydrogen with an Mg-Al alloy pre-exposed to air have been studied with in situ time resolved X-ray powder diffraction. Phase fractions as a function of time are derived from series of consecutive diffraction patterns allowing kinetic analysis. The apparent activation energy for dehydrogenation of the Mg-Al alloy is found to be 160 kJ/mol. This is not significantly higher than for pure and fully activated Mg. It is suggested that the addition of Al improves the resistance towards oxygen contamination

  9. Tritium permeation through iron

    International Nuclear Information System (INIS)

    Hagi, Hideki; Hayashi, Yasunori

    1989-01-01

    An experimental method for measuring diffusion coefficients and permeation rates of tritium in metals around room temperature has been established, and their values in iron have been obtained by using the method. Permeation rates of tritium and hydrogen through iron were measured by the electrochemical method in which a tritiated aqueous solution was used as a cathodic electrolyte. Tritium and hydrogen were introduced from one side of a membrane specimen by cathodic polarization, while at the other side of the specimen the permeating tritium and hydrogen were extracted by potentiostatical ionization. The amount of permeated hydrogen was obtained by integrating the anodic current, and that of tritium was determined by measuring the radioactivity of the electrolyte sampled from the extraction side. Diffusion coefficients of tritium (D T ) and hydrogen (D H ) were determined from the time lag of tritium and hydrogen permeation. D T =9x10 -10 m 2 /s and D H =4x10 -9 m 2 /s at 286 K for annealed iron specimens. These values of D T and D H were compared with the previous data of the diffusion coefficients of hydrogen and deuterium, and the isotope effect in diffusion was discussed. (orig.)

  10. Production method of hydrogen storage alloy electrode and hydrogen storage alloy for rechageable battery; Suiso kyuzo gokin denkyoku oyobi chikudenchiyo suiso kyuzo gokin no seizo hoho

    Energy Technology Data Exchange (ETDEWEB)

    Mizutaki, F.; Ishimaru, M.

    1995-04-07

    This invention relates to the hydrogen storage alloy electrode in which the misch metal-nickel system hydrogen storage alloy is employed. The grain of the hydrogen storage alloy is controlled so as to reduce the dendrite cell size. Since the hydrogen storage alloy having such small dendrite cell size has no part where the metal structure is too brittle, the alloy has a sufficient mechanical strength. It can stand for the swell and shrink stress associated with the sorption and desorption of hydrogen. The disintegration, therefore, due to the cracking of the alloy is hardly to take place. In addition, the quenching of molten alloy at a cooling rate of 1000{degree}C/sec or faster suppresses the occurrence of segregation of any alloy element at the grain boundary, making it possible to produce the homogeneous and mechanically strong alloy. In other words, it can be achieved to produce a hydrogen storage alloy electrode having an excellent cycle property. 4 figs., 1 tab.

  11. Hydrogen Induced Intergranular Cracking of Nickel-Base Alloys.

    Science.gov (United States)

    1982-02-01

    alloys are discussed. Experimental The steel used in the present investigation is a fully bainitic 2 1/4 Cr-lMo pressure vessel steel , ASTM A542 Class 3...Appendix A describes recent experiments performed in order to study the influence of plastic deformation on hydrogen transport in a 214 Cr-lMo steel (8...PLASTIC DEFORMATION ON HYDROGEN TRANSPORT IN 2 1/4 Cr-lMo STEEL M. Kurkela, G.S. Frankel, and R.M. Latanision Department of Materials Science and

  12. Development of a high strength, hydrogen-resistant austenitic alloy

    International Nuclear Information System (INIS)

    Chang, K.M.; Klahn, D.H.; Morris, J.W. Jr.

    1980-08-01

    Research toward high-strength, high toughness nonmagnetic steels for use in the retaining rings of large electrical generators led to the development of a Ta-modified iron-based superalloy (Fe-36 Ni-3 Ti-3 Ta-0.5 Al-1.3 Mo-0.3 V-0.01 B) which combines high strength with good toughness after suitable aging. The alloy did, however, show some degradation in fatigue resistance in gaseous hydrogen. This sensitivity was associated with a deformation-induced martensitic transformation near the fracture surface. The addition of a small amount of chromium to the alloy suppressed the martensite transformation and led to a marked improvement in hydrogen resistance

  13. Surface hardening of Ti-6Al-4V alloy by hydrogenation

    International Nuclear Information System (INIS)

    Wu, T.I.; Wu, J.K.

    1991-01-01

    Thermochemical processing is an advanced method to enhance the fabricability and mechanical properties of titanium alloys. In this process hydrogen is added to the titanium alloy as a temporary alloying element. Hydrogen addition lowers the β transus temperature of titanium alloy and stabilizes the β phase. The increased amount of β phase in hydrogen-modified titanium alloys reduces the grain growth rate during eutectoid β → α + hydride reaction. Hydrogen was added to the titanium alloy by holding it at a relatively high temperature in a hydrogen gaseous environment in previous studies. Pattinato reported that Ti-6Al-4V alloy can react with hydrogen gas at ambient temperature and cause a serious hydrogen embrittlement problem. The hydrogen must be removed to a low allowable concentration in a vacuum system after the hydrogenation process. The present study utilized an electrochemical technique to dissolve hydrogen into titanium alloy to replace the hydrogen environment in thermochemical processing. In this paper microstructures and hardnesses of this new processed Ti-6Al-4V alloy are reported

  14. Improved Mg-based alloys for hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Sapru, K.; Ming, L.; Stetson, N.T.; Evans, J. [Energy Conversion Devices, Inc., Troy, MI (United States)

    1998-08-01

    The overall objective of this on-going work is to develop low temperature alloys capable of reversibly storing at least 3 wt.% hydrogen, allowing greater than for 2 wt.% at the system level which is required by most applications. Surface modification of Mg can be used to improve its H-sorption kinetics. The authors show here that the same Mg-transition metal-based multi-component alloy when prepared by melt-spinning results in a more homogeneous materials with a higher plateau pressure as compared to preparing the material by mechanical grinding. They have also shown that mechanically alloyed Mg{sub 50}Al{sub 45}Zn{sub 5} results in a sample having a higher plateau pressure.

  15. Hydriding properties of an Mg-Al-Ni-Nd hydrogen storage alloy

    International Nuclear Information System (INIS)

    Duarte, G.I.; Bustamante, L.A.C.; Miranda, P.E.V. de

    2007-01-01

    This work presents the development of an Mg-Al-Ni-Nd alloy for hydrogen storage purposes. The hydrogen storage properties of the alloy were analyzed using pressure-composition isotherms and hydrogen desorption kinetic curves at different temperatures. The characterization of the microstructures, before and after hydrogenation, was performed using X-ray diffraction, scanning electron microscopy and energy-dispersive spectrometry. Hydrogenation caused significant changes in the alloy microstructure. Two pressure plateaus were observed. The maximum hydrogen storage reversible capacity measured was 4 wt.% at 573 K

  16. Alloys for hydrogen storage in nickel/hydrogen and nickel/metal hydride batteries

    Science.gov (United States)

    Anani, Anaba; Visintin, Arnaldo; Petrov, Konstantin; Srinivasan, Supramaniam; Reilly, James J.; Johnson, John R.; Schwarz, Ricardo B.; Desch, Paul B.

    1993-01-01

    Since 1990, there has been an ongoing collaboration among the authors in the three laboratories to (1) prepare alloys of the AB(sub 5) and AB(sub 2) types, using arc-melting/annealing and mechanical alloying/annealing techniques; (2) examine their physico-chemical characteristics (morphology, composition); (3) determine the hydrogen absorption/desorption behavior (pressure-composition isotherms as a function of temperature); and (4) evaluate their performance characteristics as hydride electrodes (charge/discharge, capacity retention, cycle life, high rate capability). The work carried out on representative AB(sub 5) and AB(sub 2) type modified alloys (by partial substitution or with small additives of other elements) is presented. The purpose of the modification was to optimize the thermodynamics and kinetics of the hydriding/dehydriding reactions and enhance the stabilities of the alloys for the desired battery applications. The results of our collaboration, to date, demonstrate that (1) alloys prepared by arc melting/annealing and mechanical alloying/annealing techniques exhibit similar morphology, composition and hydriding/dehydriding characteristics; (2) alloys with the appropriate small amounts of substituent or additive elements: (1) retain the single phase structure, (2) improve the hydriding/dehydriding reactions for the battery applications, and (3) enhance the stability in the battery environment; and (3) the AB(sub 2) type alloys exhibit higher energy densities than the AB(sub 5) type alloys but the state-of-the-art, commercialized batteries are predominantly manufactured using Ab(sub 5) type alloys.

  17. Hydrogen-plasticity interactions in nickel and nickel base alloys

    International Nuclear Information System (INIS)

    Girardin, G.

    2004-03-01

    We evaluate the different contributions of the hydrogen-dislocation interactions to the plasticity of fcc materials in order to feed predictive models of stress corrosion cracking. Static strain ageing experiments are used to quantify the hardening contribution of solute drag by dislocations to the flow stress. We demonstrate the role of hydrogen transport by dislocations on the fracture mechanism. We model the influence of the screening of the elastic field of dislocations by hydrogen on elementary plasticity mechanisms and we conclude that the decrease of the cross slip ability arises from the combined action of elastic and core effects. The testing of single crystals shows that the major effect is on the cross slip mechanism. Tensile tests on polycrystals enlighten the diversity of macroscopic responses observed in alloys. (author)

  18. A mechanism for the hydrogen uptake process in zirconium alloys

    International Nuclear Information System (INIS)

    Cox, B.

    1999-01-01

    Hydrogen uptake data for thin Zircaloy-2 specimens in steam at 300-400 C have been analysed to show that there is a decrease in the rate of uptake with respect to the rate of oxidation when the terminal solid solubility (TSS) of hydrogen in the metal is exceeded. In order for TSS to be reached during pre-transition oxidation a very thin 0.125 mm Zircaloy sheet was used. The specimens had been pickled initially removing all Zr 2 (Fe/Ni) particles from the initial surfaces, yet the initial hydrogen uptake rates were still much higher than for Zircaloy-4 or a binary Zr/Fe alloy that did not contain phases that dissolve readily during pickling. Cathodic polarisation at room temperature in CuSO 4 solution showed that small cracks or pores formed the cathodic sites in pre-transition oxide films. Some were at pits resulting from the initial dissolution of the Zr 2 (Fe/Ni) phase; others were not; none were at the remaining intermetallics in the original surface. These small cracks are thought to provide the ingress routes for hydrogen. A microscopic steam starvation process at the bottoms of these small cracks or pores, leading to the accumulation of hydrogen adjacent to the oxide/metal interface, and causing breakdown of the passive oxide forming at the bottom of the flaw, is thought to provide the mechanism for the hydrogen uptake process during both pre-transition and post-transition oxidation. (orig.)

  19. Low temperature heat capacity of lutetium and lutetium hydrogen alloys

    International Nuclear Information System (INIS)

    Thome, D.K.

    1977-10-01

    The heat capacity of high purity electrotransport refined lutetium was measured between 1 and 20 0 K. Results for theta/sub D/ were in excellent agreement with theta values determined from elastic constant measurements. The heat capacity of a series of lutetium-hydrogen solid solution alloys was determined and results showed an increase in γ from 8.2 to about 11.3 mJ/g-atom-K 2 for hydrogen content increasing from zero to about one atomic percent. Above one percent hydrogen γ decreased with increasing hydrogen contents. The C/T data showed an increase with temperature decreasing below about 2.5 0 K for samples with 0.1 to 1.5 atomic percent hydrogen. This accounts for a large amount of scatter in theta/sub D/ versus hydrogen content in this range. The heat capacity of a bulk sample of lutetium dihydride was measured between 1 and 20 0 K and showed a large increase in theta/sub D/ and a large decrease in γ compared to pure lutetium

  20. Mechanochemical synthesis of nanostructured chemical hydrides in hydrogen alloying mills

    International Nuclear Information System (INIS)

    Wronski, Z.; Varin, R.A.; Chiu, C.; Czujko, T.; Calka, A.

    2007-01-01

    Mechanical alloying of magnesium metal powders with hydrogen in specialized hydrogen ball mills can be used as a direct route for mechanochemical synthesis of emerging chemical hydrides and hydride mixtures for advanced solid-state hydrogen storage. In the 2Mg-Fe system, we have successfully synthesized the ternary complex hydride Mg 2 FeH 6 in a mixture with nanometric Fe particles. The mixture of complex magnesium-iron hydride and nano-iron released 3-4 wt.%H 2 in a thermally programmed desorption experiment at the range 285-295 o C. Milling of the Mg-2Al powder mixture revealed a strong competition between formation of the Al(Mg) solid solution and the β-MgH 2 hydride. The former decomposes upon longer milling as the Mg atoms react with hydrogen to form the hydride phase, and drive the Al out of the solid solution. The mixture of magnesium dihydride and nano-aluminum released 2.1 wt.%H 2 in the temperature range 329-340 o C in the differential scanning calorimetry experiment. The formation of MgH 2 was suppressed in the Mg-B system; instead, a hydrogenated amorphous phase (Mg,B)H x , was formed in a mixture with nanometric MgB 2 . Annealing of the hydrogen-stabilized amorphous mixture produced crystalline MgB 2

  1. Multiscale modelling of hydrogen embrittlement in zirconium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Majevadia, Jassel; Wenman, Mark; Balint, Daniel; Sutton, Adrian [Imperial College London (United Kingdom); Nazarov, Roman [MPIE, Dusseldorf (Germany)

    2013-07-01

    Delayed Hydride Cracking (DHC) is a commonly occurring embrittlement phenomenon in zirconium alloy fuel cladding within Pressurized Water Reactors (PWRs). DHC is caused by the accumulation of hydrogen atoms taken up by the metal, and the formation of brittle hydrides in the vicinity of crack tips. The rate of crack growth is limited by the rate of hydrogen diffusion to the crack, which can be modelled by solving a stress driven diffusion equation that incorporates the elastic interaction between defects. This of interest in the present work. The elastic interaction is calculated by combining defect forces determined through Density Functional Theory (DFT) simulations, and an exact solution for the anisotropic elastic field of an edge dislocation in Zr. making it possible to determine the interaction energy without the need to simulate directly a hydrogen atom in the presence of a crack or dislocation, which is computationally prohibitive with DFT. The result of the elastic interaction energy calculations can be utilised to determine the segregation of hydrogen to a crack tip for varying crack tip geometries, and in the presence of other crystal defects. This is done by implementing a diffusion equation for hydrogen within a discrete dislocation dynamics simulation. In the present work a model has been developed to demonstrate the effect of a single dislocation on hydrogen diffusion to create a Cottrell atmosphere.

  2. The Effect of Cold Rolling on the Hydrogen Susceptibility of 5083 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    E.P. Georgiou

    2017-10-01

    Full Text Available This work focuses in investigating the effect of cold deformation on the cathodic hydrogen charging of 5083 aluminum alloy. The aluminium alloy was submitted to a cold rolling process, until the average thickness of the specimens was reduced by 7% and 15%, respectively. A study of the structure, microhardness, and tensile properties of the hydrogen charged aluminium specimens, with and without cold rolling, indicated that the cold deformation process led to an increase of hydrogen susceptibility of this aluminum alloy.

  3. Measurements of the electrical resistance and the hydrogen depth distribution for Ni 60Nb 20Zr 20 amorphous alloy before and after hydrogen charging

    Science.gov (United States)

    Nakano, Sumiaki; Ohtsu, Naofumi; Nagata, Shinji; Yamaura, Shin-ichi; Uchinashi, Sakae; Kimura, Hisamichi; Shikama, Tatsuo; Inoue, Akihisa

    2005-02-01

    A Ni 60Nb 20Zr 20 amorphous alloy was prepared by the single-roller melt-spinning technique. The change in the electrical resistance of the alloy after electrochemical hydrogen charging in 6 N KOH solution was investigated. The change in the hydrogen depth distribution in the alloy was also investigated by elastic recoil detection. As a result, we found that the electrical resistance of the alloy increases with increasing the hydrogen content in the alloy and that a large number of hydrogen atoms are remained in the surface area of the hydrogen-charged alloy.

  4. Positron annihilation in hydrogenated and electron-irradiated titanium alloys

    International Nuclear Information System (INIS)

    Mukashev, K.M.; Zaikin, Yu.A.

    2002-01-01

    that material properties were not completely recovered, probably due to residual point defects of radiation origin. It is obvious that the temperature of 600 deg. C was not sufficient for hydrogen extraction from titanium. These results are confirmed by data of previous studies where niobium and nickel hydrogenated after electron irradiation were studied. These data show that the shift in the recovery start exceeded 130 deg. C. Thus, interaction of vacancy-type defects with previously introduced hydrogen surrounding causes alterations in the efficient size of positron localization centers and shifts the first recovery stage to the region of higher temperature values. Generally, the results of this study demonstrate a significant role of hydrogen in alterations of the electron structure of damaged materials. They show the increasing hydrogen interaction with materials in presence of structural imperfections of deformational and radiation origin. Both hydrogen behavior in irradiated titanium alloys and the observed alterations in positron annihilation characteristics cannot be described in frames of a simple model based on the concept of proton interaction with a vacancy. Variety of radiation defects, such as complexes of point defects, dislocations, cracks, etc., should be taken into account. Application of positron annihilation methods provides important information on hydrogen interaction with lattice imperfections that can be a useful approach to the problem of hydrogen embrittlement of structural materials in the fields of ionizing radiation

  5. Effect of hydrogen addition on the microstructure of TC21 alloy

    International Nuclear Information System (INIS)

    Zhu Tangkui; Li Miaoquan

    2010-01-01

    Research highlights: → The aim of this paper is to study the effect of hydrogen content (0-0.887 wt.%H) on microstructure, phase composition, microhardness and β transus temperature of TC21 alloy. The results show that, with increasing hydrogen content, the β phase increases, the α/β interfaces of lamellar transformed β phase disappear, the lattice parameter of β phase increases and the β transus temperature decreases for the hydrogenated TC21 alloy. In comparison to the as-received TC21 alloy, the contrasts of primary α phase and transformed β phase under optical microscope in the TC21 alloy with high hydrogen content are reversed completely. Furthermore, the γ and δ hydrides are detected in the hydrogenated TC21 alloy. In addition, the variations of phase compositions for the hydrogenated TC21 alloy have influence on microhardness and β transus temperature. → In conclusion, this paper shows some significant rules about the influence of hydrogen on TC21 alloy. - Abstract: TC21 alloy was hydrogenated at 750 deg. C with different hydrogen contents ranging from 0 to 0.873 wt.%H, and its microstructural evolution and phase transformations were investigated by optical microscopy (OM) and X-ray diffraction (XRD). The microhardness and the β transus temperature for the hydrogenated TC21 alloy were determined by microhardness testing and metallographical approach, respectively. The results show that, hydrogen addition has a noticeable influence on microstructure, phase composition, microhardness and β transus temperature of TC21 alloy. With increasing hydrogen content, the β phase increases, the α/β interfaces of lamellar transformed β phase disappear, the lattice parameter of β phase increases and the β transus temperature decreases for the hydrogenated TC21 alloy. In comparison to the as-received TC21 alloy, the contrasts of primary α phase and transformed β phase under optical microscope in the hydrogenated TC21 alloy with high hydrogen

  6. A novel method for producing magnesium based hydrogen storage alloys

    International Nuclear Information System (INIS)

    Walton, A.; Matthews, J.; Barlow, R.; Almamouri, M.M.; Speight, J.D.; Harris, I.R.

    2003-01-01

    Conventional melt casting techniques for producing Mg 2 Ni often result in no stoichiometric compositions due to the excess Mg which is added to the melt in order to counterbalance sublimation during processing. In this work a vapour phase process known as Low Pressure Pack Sublimation (LPPS) has been used to coat Ni substrates with Mg at 460-600 o C producing layers of single phase Mg 2 Ni. Ni substrates coated to date include powder, foils and wire. Using Ni-Fe substrates it has also been demonstrated that Fe can be distributed through the Mg 2 Ni alloy layer which could have a beneficial effect on the hydrogen storage characteristics. The alloy layers formed have been characterised by XRD and SEM equipped with EDX analysis. Hydrogen storage properties have been evaluated using an Intelligent Gravimetric Analyser (IGA). LPPS avoids most of the sintering of powder particles during processing which is observed in other vapour phase techniques while producing a stoichiometric composition of Mg 2 Ni. It is also a simple, low cost technique for producing these alloys. (author)

  7. Influence of adsorbed carbon dioxide on hydrogen electrosorption in palladium-platinum-rhodium alloys

    International Nuclear Information System (INIS)

    Lukaszewski, M.; Grden, M.; Czerwinski, A.

    2004-01-01

    Carbon dioxide electroreduction was applied to examine the processes of hydrogen electrosorption (adsorption, absorption and desorption) by thin electrodeposits of Pd-Pt-Rh alloys under conditions of cyclic voltammetric (CV) experiments. Due to different adsorption characteristics towards the adsorption product of the electroreduction of CO 2 (reduced CO 2 ) exhibited by the alloy components hydrogen adsorption and hydrogen absorption signals can be distinguished on CV curves. Reduced CO 2 causes partial blocking of hydrogen adsorbed on surface Pt and Rh atoms, without any significant effect on hydrogen absorption into alloy. It reflects the fact that adsorbed hydrogen bonded to Pd atoms does not participate in CO 2 reduction, while hydrogen adsorbed on Pt and Rh surface sites is inactive in the absorption reaction. In contrast, CO is adsorbed on all alloy components and causes a marked inhibition of hydrogen sorption (both adsorption and absorption)/desorption reactions

  8. Zirconium-nickel crystals—hydrogen accumulators: Dissolution and penetration of hydrogen atoms in alloys

    Science.gov (United States)

    Matysina, Z. A.; Zaginaichenko, S. Yu.; Shchur, D. V.; Gabdullin, M. T.; Kamenetskaya, E. A.

    2016-07-01

    The calculation of the free energy, thermodynamic equilibrium equations, and kinetic equations of the intermetallic compound Zr2NiH x has been carried out based on molecular-kinetic concepts. The equilibrium hydrogen concentration depending on the temperature, pressure, and energy parameters has been calculated. The absorption-desorption of hydrogen has been studied, and the possibility of the realization of the hysteresis effect has been revealed. The kinetics of the dissolution and permeability of hydrogen is considered, the time dependence of these values has been found, and conditions for the extremum character of their time dependence have been determined. Relaxation times of the dissolution and permeability of hydrogen into the alloy have been calculated. The calculation results are compared with the experimental data available in the literature.

  9. Hydrogen traps in the oxide/alloy interface region of Zr-Nb alloys

    International Nuclear Information System (INIS)

    Khatamian, D.

    1995-03-01

    In this study the 1 H( 15 N,αγ) 12 C nuclear reaction has been used to measure hydrogen profiles of anodically oxidized Zr-Nb specimens containing various amounts of niobium. The profiles have been correlated with oxygen profiles, obtained using a Scanning Auger Microprobe (SAM), and with X-ray diffraction patterns. In addition, unoxidized Zr-2.5Nb (Zr-2.5 wt% Nb) samples were implanted with oxygen and hydrogen to study the interaction between these two species when dissolved in the alloy. All the anodically oxidized specimens, except the pure Zr and the single-phase β-Zr (Zr-20Nb) samples, displayed hydrogen peaks beneath the oxide layer. These results, in conjunction with the results from the implanted specimens, indicate that the hydrogen moves under the influence of a stress gradient to the sub-oxide region, where the metal lattice has been expanded due to superficial oxide growth. The results show that dissolved oxygen sites in Zr-2.5Nb alloy do not trap hydrogen. (author). 16 refs., 6 figs

  10. The Synergetic Effects of Hydrogen and Oxygen on the Strength and Ductility of Vanadium Alloys

    Institute of Scientific and Technical Information of China (English)

    Chen Jiming(谌继明); Xu Ying(徐颖); Deng Ying(邓颖); Yang Ling(杨霖); Qiu Shaoyu(邱绍宇)

    2003-01-01

    A V4Ti alloy and several V4Cr4Ti alloys with different oxygen contents were studied on their tensile properties with the effect of hydrogen concentrations. The ductility of the alloys showed a successive decrease in a varied rate with an increased hydrogen concentration, while the ultimate tensile strength remained unchanged or even decreased for the high oxygen content alloy in spite of the occurrence of hardening in the low oxygen content alloy. Oxygen in the alloy causes grain boundary weakening, increasing the possibility of intergranular fractures and thus enhancing the hydrogen embrittlement. V4Ti showed a higher resistance to the hydrogen embrittlement as compared to the V4Cr4Ti alloys on a similar oxygen content level.

  11. Studies of effects on determination of trace hydrogen in U-Nb alloy

    International Nuclear Information System (INIS)

    Zou Lexi; Li Yingqiu; Liu Jun; Wu Lunqiang; Qi Lianzhu; Bian Min

    2002-01-01

    The affecting factors for determination of trace hydrogen in U-Nb alloy are studied. The status of samples affects greatly the measured hydrogen content, which has the higher value for scrap sample than cylinder sample. The hydrogen content in cylinder is closer to real value in U-Nb alloy. The hydrogen in U-Nb alloy is mainly from surface adsorption. The results of hydrogen determined by vacuum thermal evolved method, in which the relative standard uncertainty is less than 28%, are in agreement with those by inert-gas fusion method

  12. Hydrogen absorption study of Ti-based alloys performed by melt-spinning

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, R.M.; Lemus, L.F.; Santos, D.S. dos, E-mail: rafaella@metalmat.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (PEMM/COPPEP/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Metalurgica e de Materiais

    2013-11-01

    The hydrogen absorption and desorption of Ti{sub 53}Zr{sub 27}Ni{sub 20} icosahedral quasicrystal (ICQ) and Ti{sub 50}Ni{sub 50} shape memory alloy (SMA) melt-spun ribbons was studied. Samples were exposed to hydrogen gas at 623 K and 4 MPa for 1000 minutes. The total capacity of hydrogen obtained for Ti{sub 53}Zr{sub 27}Ni{sub 20} and Ti{sub 50}Ni{sub 50} was 3.2 and 2.4 wt. % respectively. The Thermal Desorption Spectrometry (TDS) of the hydrogenated alloys shows that both alloys start to desorb hydrogen around 750 K. X-ray diffraction (XRD) patterns, performed after hydrogenation, indicate a complete amorphization of the Ti{sub 53}Zr{sub 27}Ni{sub 20} i-phase alloy, while the Ti{sub 50}Ni{sub 50} alloy remained crystalline after hydride formation. (author)

  13. Hydrogen adsorption on bimetallic PdAu(111) surface alloys

    DEFF Research Database (Denmark)

    Takehiro, Naoki; Liu, Ping; Bergbreiter, Andreas

    2014-01-01

    The adsorption of hydrogen on structurally well defined PdAu-Pd(111) monolayer surface alloys was investigated in a combined experimental and theoretical study, aiming at a quantitative understanding of the adsorption and desorption properties of individual PdAu nanostructures. Combining...... the structural information obtained by high resolution scanning tunneling microscopy (STM), in particular on the abundance of specific adsorption ensembles at different Pd surface concentrations, with information on the adsorption properties derived from temperature programmed desorption (TPD) spectroscopy...... and high resolution electron energy loss spectroscopy (HREELS) provides conclusions on the minimum ensemble size for dissociative adsorption of hydrogen and on the adsorption energies on different sites active for adsorption. Density functional theory (DFT) based calculations give detailed insight...

  14. Hydrogen storage in thin film magnesium-scandium alloys

    International Nuclear Information System (INIS)

    Niessen, R.A. H.; Notten, P.H. L.

    2005-01-01

    Thorough electrochemical materials research has been performed on thin films of novel magnesium-scandium hydrogen storage alloys. It was found that palladium-capped thin films of Mg x Sc (1-x) with different compositions (ranging from x=0.50 -0.90) show an increase in hydrogen storage capacity of more than 5-20% as compared to their bulk equivalents using even higher discharge rates. The maximum reversible hydrogen storage capacity at the optimal composition (Mg 80 Sc 20 ) amounts to 1795-bar mAh/g corresponding to a hydrogen content of 2.05 H/M or 6.7-bar wt.%, which is close to five times that of the commonly used hydride-forming materials in commercial NiMH batteries. Galvanostatic intermittent titration technique (GITT) measurements show that the equilibrium pressure during discharge is lower than that of bulk powders by one order of magnitude (10 -7 -bar mbar versus 10 -6 -bar mbar, respectively)

  15. Alloys influence in ferritic steels with hydrogen attack

    International Nuclear Information System (INIS)

    Moro, L; Rey Saravia, D; Lombardich, J; Saggio, M; Juan, A; Blanco, J

    2003-01-01

    Materials exposed to a corrosive environment and high temperatures, are associated with a decrease of their mechanical properties and embitterment.At room temperatures atomic hydrogen diffuses easily through metals structure, it accumulates in lattice defects forming molecular hydrogen and generating cracking due to internal stresses.Under high temperatures the phenomenon is more complex.The steels in these conditions present different structures of precipitates, that the change under creep conditions period.In this work it is determined the influence of Cr and V alloys, the changes of ferritic steel resistance in a corrosive environment and high temperatures.1.25 Cr 1 Mo 0.25 V and 2.25Cr 1 Mo under different loads and temperatures previously attacked by hydrogen environment.The hydrogen is induced by the electrolytic technique, optimizing the choice of temperatures, current density, electrolyte, etc. In order to control an adequate cathode charge, a follow up procedure is carried out by electronic barrier microscopy.After the attack, the material is settled at room temperatures for certain period of time, to allow the hydrogen to leave and evaluate the residual damage.Creep by torsion assays, under constant load and temperature is used as an experimental technique.With the outcome data curves are drawn in order to study the secondary creep rate, with the applied load and temperature, determining the value of stress exponent n and the activation energy Q.Comparing to equal assays to the same ferritic steels but non attacked by hydrogen, these values allows the prediction of microstructure changes present during these tests

  16. Influence of hydrogen additions on high-temperature superplasticity of titanium alloys

    International Nuclear Information System (INIS)

    Lederich, R.J.; Sastry, S.M.L.

    1982-01-01

    The effects of the addition of up to 1.0 wt pct hydrogen as a transient alloying element on the superplastic formability (SPF) of fine-grained, equiaxed Ti-6Al-4V (Ti-64) and duplex-annealed Ti-6Al-2Sn-4Zr-2Mo (Ti-6242) were determined. Small amounts of internal hydrogen greatly improve the SPF of the alloys. Formability at 720-900 C was evaluated by an instrumented cone-forming test with continuous monitoring of strain with time. Argon/1 pct hydrogen and argon/4 pct hydrogen gas mixtures were used for charging the alloys with hydrogen as well as for superplastic forming. Hydrogen additions lower the beta-transus temperature of alpha-beta titanium alloys, and the proportions of the alpha and beta phases required for optimum superplasticity can thus be obtained at lower temperatures in hydrogen-modified alloys than in standard alloys. The increased amount of beta phase in the hydrogen-modified titanium alloys reduces the grain growth rates at forming temperature, thus reducing the time-dependent decrease in superplastic strain rate at constant stress or the increase in flow stress at constant strain rate. Process parameters for superplastic forming of Ti-64 and Ti-6242 using argon-hydrogen gas mixtures were determined. 8 references

  17. Hydrogen-induced room-temperature plasticity in TC4 and TC21 alloys

    DEFF Research Database (Denmark)

    Yuan, Baoguo; Jin, Yongyue; Hong, Chuanshi

    2017-01-01

    In order to reveal the effect of hydrogen on the room-temperature plasticity of the titanium alloys TC4 and TC21, compression tests have been carried out at room temperature. Results show that an appropriate amount of hydrogen can improve the room-temperature plasticity of both the TC4 and TC21...... alloys. The ultimate compression strain of the TC4 alloy containing a hydrogen concentration of 0.5 wt.% increases by 39% compared to the untreated material. For the TC21 alloy the ultimate compression strain is increased by 33% at a hydrogen concentration of 0.6 wt.%. The main reason for the improvement...... of hydrogen-induced room-temperature plasticity of the TC4 and TC21 alloys is discussed....

  18. Investigation of hydrogen-deformation interactions in β-21S titanium alloy using thermal desorption spectroscopy

    International Nuclear Information System (INIS)

    Tal-Gutelmacher, E.; Eliezer, D.; Boellinghaus, Th.

    2007-01-01

    The focus of this paper is the investigation of the combined influence of hydrogen and pre-plastic deformation on hydrogen's absorption/desorption behavior, the microstructure and microhardness of a single-phased β-21S alloy. In this study, thermal desorption analyses (TDS) evaluation of various desorption and trapping parameters provide further insight on the relationships between hydrogen absorption/desorption processes and deformation, and their mutual influence on the microstructure and the microhardness of β-21S alloy. TDS spectra were supported by other experimental techniques, such as X-ray diffraction, scanning and transmission electron microscopy, hydrogen quantity analyses and microhardness tests. Pre-plastic deformation, performed before the electrochemical hydrogenation of the alloy, increased significantly the hydrogen absorption capacity. Its influence was also evident on the notably expanded lattice parameter of β-21S alloy after hydrogenation. However, no hydride precipitation was observed. An interesting softening effect of the pre-deformed hydrogenated alloy was revealed by microhardness tests. TDS demonstrated the significant effect of pre-plastic deformation on the hydrogen evolution process. Hydrogen desorption temperature and the activation energy for hydrogen release increased, additional trap states were observed and the amount of desorbed hydrogen decreased

  19. Effect of hydrogen on the corrosion behavior of the Mg–xZn alloys

    Directory of Open Access Journals (Sweden)

    Yingwei Song

    2014-09-01

    Full Text Available Hydrogen evolution reaction is inevitable during the corrosion of Mg alloys. The effect of hydrogen on the corrosion behavior of the Mg–2Zn and Mg–5Zn alloys is investigated by charging hydrogen treatment. The surface morphologies of the samples after charging hydrogen were observed using a scanning electron microscopy (SEM and the corrosion resistance was evaluated by polarization curves. It is found that there are oxide films formed on the surface of the charged hydrogen samples. The low hydrogen evolution rate is helpful to improve the corrosion resistance of Mg alloys, while the high hydrogen evolution rate can increases the defects in the films and further deteriorates their protection ability. Also, the charging hydrogen effect is greatly associated with the microstructure of Mg substrate.

  20. New vistas in the determination of hydrogen in aerospace engine metal alloys

    Science.gov (United States)

    Danford, M. D.

    1986-01-01

    The application of diffusion theory to the analysis of hydrogen desorption data has been studied. From these analyses, important information concerning hydrogen solubilities and the nature of the hydrogen distributions in the metal has been obtained. Two nickel base alloys, Rene' 41 and Waspaloy, and one ferrous alloy, 4340 steel, were studied in this work. For the nickel base alloys, it was found that the hydrogen distributions after electrolytic charging conformed closely to those which would be predicted by diffusion theory. The hydrogen distributions in electrolytically charged 4340 steel, on the other hand, were essentially uniform in nature, which would not be predicted by diffusion theory. Finally, it has been found that the hydrogen desorption is completely explained by the nature of the hydrogen distribution in the metal, and that the 'fast' hydrogen is not due to surface and subsurface hydride formation, as was originally proposed.

  1. Hydrogen storage alloy electrode for nickel-hydrogen storage battery use; Nikkeru-suiso chikudenchiyo suiso kyuzo gokin denkyoku

    Energy Technology Data Exchange (ETDEWEB)

    Nagase, H.; Tadokoro, M.

    1995-06-16

    In the conventional hydrogen storage alloy electrode, water soluble polymer is employed as for the binder. Employing the water soluble polymer as for the binder may cause the film formation on the surface of the hydrogen storage alloy to hinder the hydrogen absorption at the alloy surface, resulting in the decrease in activity of electrode and in the discharge characteristic at a low temperature. This invention proposes the addition of Vinylon fiber in the binder of the hydrogen storage alloy electrode made by kneading the hydrogen storage alloy and the binder. The Vinylon fiber improves the strength of the electrode, as it forms a network in the electrode. Furthermore, the point contact between the alloy and the Vinylon fiber in the electrode prevents the film formation which hinders the oxygen absorption and chemical reaction on the surface of the alloy. As for the binder, carboxymethyl cellulose is used. The preferable size of Vinylon fiber is fiber diameter of 0.1 - 0.5 denier and fiber length of 0.5 - 5.0 mm. 4 figs., 4 tabs.

  2. Study of the input-side subsurface reorganization vs. the outside current density in hydrogen permeation under constant cell voltage through iron membrane according to RHC concept

    International Nuclear Information System (INIS)

    DePetris-Wery, M.; Wery, S.; Catonne, J.C.

    2010-01-01

    In this work, hydrogen permeation tests were performed on pure iron membrane in 1 M sodium hydroxide at 298 K, subjected to hydrogen charging under 'quasi-potentiostatic' polarization conditions, i.e. constant cell voltage applied between the cathode (membrane entry side) and the anode (counter electrode), which is a typical situation during metal electrodeposition or cathodic degreasing on steel in metal finishing industry. Two consecutive charging-discharging runs were carried out. Prolonged hydrogen charging under quasi-potentiostatic polarization was investigated and the change of cathodic current density (i in ) chg and electrode potential (E in ) chg as well as permeation current density (i out ) chg were analysed. Three singularities were underlined for each experiment: (i) the curve (i in ) chg = f((E in ) chg ), illustrating the inverse of hydrogen charge resistance R HC -1 evolution which was negative, equal to zero and then became positive; (ii) quasi-periodic instabilities during the R HC -1 zero period, probably induced by atomic reorganizing due to subsurface hydrogen insertion in the input-side; (iii) the same ratio (i out ) chg /(i in ) chg = -6 x 10 -5 . During discharge runs, both sides of the membrane were polarized at the same potential (E in ) dischg = (E out ) dischg = -0.285 V/Hg/HgO/NaOH 1 M and the current densities, (i in ) dischg and (i out ) dischg which corresponded to the desorption rates of hydrogen, were measured. The following correlation (i out ) dischg vs.(i in ) dischg = -6 x 10 -5 was confirmed leading us to introduce the R HC -1 mirror concept to observe the input-side subsurface reorganization by the survey of its potential vs. outside current density during the hydrogen charge. Thus, this R HC -1 mirror concept showed: (i) a non-stop and irreversible progress in the subsurface reorganization during the two permeations; (ii) a probable structural evolution to a stable subsurface structure, the only condition of a real steady

  3. Heat of solution and site energies of hydrogen in disordered transition-metal alloys

    International Nuclear Information System (INIS)

    Brouwer, R.C.; Griessen, R.

    1989-01-01

    Site energies, long-range effective hydrogen-hydrogen interactions, and the enthalpy of solution in transition-metal alloys are calculated by means of an embedded-cluster model. The energy of a hydrogen atom is assumed to be predominantly determined by the first shell of neighboring metal atoms. The semiempirical local band-structure model is used to calculate the energy of the hydrogen atoms in the cluster, taking into account local deviations from the average lattice constant. The increase in the solubility limit and the weak dependence of the enthalpy of solution on hydrogen concentration in disordered alloys are discussed. Calculated site energies and enthalpies of solution in the alloys are compared with experimental data, and good agreement is found. Due to the strong interactions with the nearest-neighbor metal atoms, hydrogen atoms can be used to determine local lattice separations and the extent of short-range order in ''disordered'' alloys

  4. Treatment method of hydrogen storage alloy for battery; Denchiyo suiso kyuzo gokin no shori hoho

    Energy Technology Data Exchange (ETDEWEB)

    Negi, Y.; Kaminaka, H.; Nagata, T.; Takeshita, Y.

    1997-04-04

    A nickel-hydrogen battery using a hydrogen storage alloy takes considerably long time for the initial activation treatment after the assembly of the battery. In this invention, a hydrogen storage alloy containing nickel is immersed in an aqueous acid solution or an aqueous alkaline solution and washed with a solution containing a complexing agent to form a nickel complex by a reaction with Ni(OH)2 in a concentration of 10{sup -6} to 10{sup -1} followed by washing with water. By using this method, hydroxides, particularly, Ni(OH)2 deposited on the alloy surface on the treatment of the hydrogen storage alloy with aqueous acid or alkaline solution can be removed efficiently to afford the hydrogen storage alloy with a high initial activity. The hydrogen storage alloy which is the object of this treatment method is AB5 type and AB2 type alloy used for a nickel-hydrogen battery and an alloy composed of nickel is particularly preferable. The complexing agent is selected from ammonia, ethylenediamine and cyanides. 2 figs., 6 tabs.

  5. Hydrogen sensor based on palladium-yttrium alloy nanosheet

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Boyi [Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan, QLD 4111 (Australia); Zhu, Yong, E-mail: y.zhu@griffith.edu.au [Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan, QLD 4111 (Australia); Chen, Youping; Song, Han; Huang, Pengcheng [School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074 (China); Dao, Dzung Viet [Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan, QLD 4111 (Australia)

    2017-06-15

    This paper presents a hydrogen sensor based on palladium-yttrium (Pd-Y) alloy nanosheet. Zigzag-shaped Pd-Y nanosheet with a thickness of 19.3 nm was deposited on a quartz substrate by using an ultrahigh-vacuum magnetron sputtering system and shadow mask. The atomic ratio of palladium to yttrium in the nanosheet was 0.92/0.08. The fabrication process was simple and low-cost, and the sensor can be mass-produced. The experimental results show the sensor has a superior sensitivity, reversibility, and reproducibility. The resistive-based hydrogen detection mechanism in this research is much simpler and more compact compared to the optical-based detection method. - Highlights: • Pd-Y sensing element was fabricated using a magnetron sputtering system and shadow mask. • The Pd-Y compound consisted of 92% Pd and 8% Y. • The fabrication process was simple, low-cost, and mass-production compatible. • The sensor showed superior sensitivity, reversibility, and reproducibility to hydrogen gas. • The device is more compact than the optical-based counterpart.

  6. Hydrogen sensor based on palladium-yttrium alloy nanosheet

    International Nuclear Information System (INIS)

    Wang, Boyi; Zhu, Yong; Chen, Youping; Song, Han; Huang, Pengcheng; Dao, Dzung Viet

    2017-01-01

    This paper presents a hydrogen sensor based on palladium-yttrium (Pd-Y) alloy nanosheet. Zigzag-shaped Pd-Y nanosheet with a thickness of 19.3 nm was deposited on a quartz substrate by using an ultrahigh-vacuum magnetron sputtering system and shadow mask. The atomic ratio of palladium to yttrium in the nanosheet was 0.92/0.08. The fabrication process was simple and low-cost, and the sensor can be mass-produced. The experimental results show the sensor has a superior sensitivity, reversibility, and reproducibility. The resistive-based hydrogen detection mechanism in this research is much simpler and more compact compared to the optical-based detection method. - Highlights: • Pd-Y sensing element was fabricated using a magnetron sputtering system and shadow mask. • The Pd-Y compound consisted of 92% Pd and 8% Y. • The fabrication process was simple, low-cost, and mass-production compatible. • The sensor showed superior sensitivity, reversibility, and reproducibility to hydrogen gas. • The device is more compact than the optical-based counterpart.

  7. Hydrogen permeation rate reduction by post-oxidation of aluminide coatings on DIN 1.4914 martensitic steel (MANET)

    International Nuclear Information System (INIS)

    Perujo, A.; Sample, T.

    1996-01-01

    In a previous work, it has been shown that lower aluminium content aluminide, having the same permeation rate reduction as the higher aluminium content, exhibited a lower hardness and greater ductility and therefore greater crack resistance than the higher aluminium content. In this work we combine this characteristic with a post-oxidation to obtain a further deuterium permeation reduction. The post-oxidation was performed in air at 1023 K for 15 h and at 1223 K for 10 h and 1 h. The maximum deuterium permeation rate reduction obtained is very moderate (maximum of a factor 500 for 1 h at 1223 K) as compared to that of the non-oxidised aluminide specimen (two orders of magnitude) and is constant in the temperature range studied (573-800 K). This method has the technological appeal of using air rather than the controlled environment used by other authors. (orig.)

  8. Effect of Microstructure and Alloy Chemistry on Hydrogen Embrittlement of Precipitation-Hardened Ni-Based Alloys

    Science.gov (United States)

    Obasi, G. C.; Zhang, Z.; Sampath, D.; Morana, Roberto; Akid, R.; Preuss, M.

    2018-04-01

    The sensitivity to hydrogen embrittlement (HE) has been studied in respect of precipitation size distributions in two nickel-based superalloys: Alloy 718 (UNS N07718) and Alloy 945X (UNS N09946). Quantitative microstructure analysis was carried out by the combination of scanning and transmission electron microscopy and energy dispersive x-ray spectroscopy (EDS). While Alloy 718 is mainly strengthened by γ″, and therefore readily forms intergranular δ phase, Alloy 945X has been designed to avoid δ formation by reducing Nb levels providing high strength through a combination of γ' and γ″. Slow strain rate tensile tests were carried out for different microstructural conditions in air and after cathodic hydrogen (H) charging. HE sensitivity was determined based on loss of elongation due to the H uptake in comparison to elongation to failure in air. Results showed that both alloys exhibited an elevated sensitivity to HE. Fracture surfaces of the H precharged material showed quasi-cleavage and transgranular cracks in the H-affected region, while ductile failure was observed toward the center of the sample. The crack origins observed on the H precharged samples exhibited quasi-cleavage with slip traces at high magnification. The sensitivity is slightly reduced for Alloy 718, by coarsening γ″ and reducing the overall strength of the alloy. However, on further coarsening of γ″, which promotes continuous decoration of grain boundaries with δ phase, the embrittlement index rose again indicating a change of hydrogen embrittlement mechanism from hydrogen-enhanced local plasticity (HELP) to hydrogen-enhanced decohesion embrittlement (HEDE). In contrast, Alloy 945X displayed a strong correlation between strength, based on precipitation size and embrittlement index, due to the absence of any significant formation of δ phase for the investigated microstructures. For the given test parameters, Alloy 945X did not display any reduced sensitivity to HE compared with

  9. Hydrogen diffusion and effect on degradation in welded microstructures of creep-resistant low-alloyed steels

    Energy Technology Data Exchange (ETDEWEB)

    Rhode, Michael

    2016-04-04

    with the permeation technique at room temperature and at elevated temperature ranges up to 400 C - It was investigated by interpreting the hydrogen effusion behavior with carrier gas hot extraction technique (CGHE). For realistic determination of the hydrogen diffusion coefficients, an improved method was developed encompassing accelerated specimen heating and hydrogen determination via mass spectrometer (MS). Simultaneously, the corresponding temperature dependent trapped and total hydrogen concentrations were determined. The determined experimental results showed increased susceptibility to the hydrogen affected degradation of the HAZ compared to the base material, which is independent of the investigated alloy composition. In particular, the martensitic coarse grain HAZ is the most susceptible microstructure to hydrogen-affected degradation. The results of the tensile tests allowed the definition of consistent microstructure specific failure criteria (envelope curves) versus quantified hydrogen concentrations for the reactor pressure vessel 16MND5 steel (20MnMoNi-5-5) and the creep-resistant T24 steel (7CrMoVTiB10-10). The procedure of quantifying hydrogen concentrations in HAZ microstructures is novel and supports a new method of analysis for hydrogen degradation effects. Further investigations with the T22 steel (10CrMo9-10), as compared to the creep-resistant T24 steel (7CrMoVTiB10-10), confirmed the beneficial effect of Vanadium as an alloying element to improve the resistance to degradation. In general, Mn-Mo-Ni base material grades show a higher resistance compared to Cr-Mo steels that do not include Vanadium alloying. The investigations showed the decreased diffusion coefficient of the HAZ microstructure compared to the base material microstructure. This is caused by the stronger trapping effects that are present which simultaneously increase the hydrogen solubility as well. In general, trapping effects above 100 C are negligible. It is noted that after

  10. Hydrogen diffusion and effect on degradation in welded microstructures of creep-resistant low-alloyed steels

    International Nuclear Information System (INIS)

    Rhode, Michael

    2016-01-01

    the permeation technique at room temperature and at elevated temperature ranges up to 400 C - It was investigated by interpreting the hydrogen effusion behavior with carrier gas hot extraction technique (CGHE). For realistic determination of the hydrogen diffusion coefficients, an improved method was developed encompassing accelerated specimen heating and hydrogen determination via mass spectrometer (MS). Simultaneously, the corresponding temperature dependent trapped and total hydrogen concentrations were determined. The determined experimental results showed increased susceptibility to the hydrogen affected degradation of the HAZ compared to the base material, which is independent of the investigated alloy composition. In particular, the martensitic coarse grain HAZ is the most susceptible microstructure to hydrogen-affected degradation. The results of the tensile tests allowed the definition of consistent microstructure specific failure criteria (envelope curves) versus quantified hydrogen concentrations for the reactor pressure vessel 16MND5 steel (20MnMoNi-5-5) and the creep-resistant T24 steel (7CrMoVTiB10-10). The procedure of quantifying hydrogen concentrations in HAZ microstructures is novel and supports a new method of analysis for hydrogen degradation effects. Further investigations with the T22 steel (10CrMo9-10), as compared to the creep-resistant T24 steel (7CrMoVTiB10-10), confirmed the beneficial effect of Vanadium as an alloying element to improve the resistance to degradation. In general, Mn-Mo-Ni base material grades show a higher resistance compared to Cr-Mo steels that do not include Vanadium alloying. The investigations showed the decreased diffusion coefficient of the HAZ microstructure compared to the base material microstructure. This is caused by the stronger trapping effects that are present which simultaneously increase the hydrogen solubility as well. In general, trapping effects above 100 C are negligible. It is noted that after testing

  11. Hydrogen calibration of GD-spectrometer using Zr-1Nb alloy

    Science.gov (United States)

    Mikhaylov, Andrey A.; Priamushko, Tatiana S.; Babikhina, Maria N.; Kudiiarov, Victor N.; Heller, Rene; Laptev, Roman S.; Lider, Andrey M.

    2018-02-01

    To study the hydrogen distribution in Zr-1Nb alloy (Э110 alloy) GD-OES was applied in this work. Qualitative analysis needs the standard samples with hydrogen. However, the standard samples with high concentrations of hydrogen in the zirconium alloy which would meet the requirements of the shape, size are absent. In this work method of Zr + H calibration samples production was performed at the first time. Automated Complex Gas Reaction Controller was used for samples hydrogenation. To calculate the parameters of post-hydrogenation incubation of the samples in an inert gas atmosphere the diffusion equations were used. Absolute hydrogen concentrations in the samples were determined by melting in the inert gas atmosphere using RHEN602 analyzer (LECO Company). Hydrogen distribution was studied using nuclear reaction analysis (HZDR, Dresden, Germany). RF GD-OES was used for calibration. The depth of the craters was measured with the help of a Hommel-Etamic profilometer by Jenoptik, Germany.

  12. Hydrogen Permeation, and Mechanical and Tribological Behavior, of CrNx Coatings Deposited at Various Bias Voltages on IN718 by Direct Current Reactive Sputtering

    Directory of Open Access Journals (Sweden)

    Egor B. Kashkarov

    2018-02-01

    Full Text Available In the current work, the microstructure, hydrogen permeability, and properties of chromium nitride (CrNx thin films deposited on the Inconel 718 superalloy using direct current reactive sputtering are investigated. The influence of the substrate bias voltage on the crystal structure, mechanical, and tribological properties before and after hydrogen exposure was studied. It was found that increasing the substrate bias voltage leads to densification of the coating. X-ray diffraction (XRD results reveal a change from mixed fcc-CrN + hcp-Cr2N to the approximately stoichiometric hcp-Cr2N phase with increasing substrate bias confirmed by wavelength-dispersive X-ray spectroscopy (WDS. The texture coefficients of (113, (110, and (111 planes vary significantly with increasing substrate bias voltage. The hydrogen permeability was measured by gas-phase hydrogenation. The CrN coating deposited at 60 V with mixed c-CrN and (113 textured hcp-Cr2N phases exhibits the lowest hydrogen absorption at 873 K. It is suggested that the crystal orientation is only one parameter influencing the permeation resistance of the CrNx coating together with the film structure, the presence of mixing phases, and the packing density of the structure. After hydrogenation, the hardness increased for all coatings, which could be related to the formation of a Cr2O3 oxide film on the surface, as well as the defect formation after hydrogen loading. Tribological tests reveal that hydrogenation leads to a decrease of the friction coefficient by up to 40%. The lowest value of 0.25 ± 0.02 was reached for the CrNx coating deposited at 60 V after hydrogenation.

  13. Effect of hydrogen on the behavior of metals II - Hydrogen embrittlement of titanium alloy TV13CA - effect of oxygen - comparison with non-alloyed titanium

    International Nuclear Information System (INIS)

    Arditty, Jean-Pierre

    1973-01-01

    The effect of oxygen on the hydrogen embrittlement of non-alloyed titanium and the metastable β titanium alloy, TV13 CA, was studied during dynamic mechanical tests, the concentrations considered varying from 1000 to 5000 ppm (oxygen) and from 0 to 5000 ppm (hydrogen) respectively. TV13 CA alloy has a very high solubility for hydrogen. The establishment of a temperature range and a rate of deformation region in which the embrittlement of the alloy is maximum leads to the conclusion that an embrittlement mechanism occurs involving the dragging and accumulation of hydrogen by dislocations. This is the case for all annealings effected in the medium temperature range, which, by favoring the re-establishment of the stable two-phase α + β state of the alloy, produce hardening. The same is true for oxygen which, in addition to hardening the alloy by the solid solution effect, tends to increase its instability and, in consequence, favors the decomposition of the β phase. Nevertheless oxygen concentrations of up to 1500 ppm contribute to increasing the mechanical resistance without catastrophically reducing the deformation capacity. In the case of non-alloyed titanium, the hardening effect also leads to an increase in E 0.2p c and R, and to a reduction in the deformation capacity. Nevertheless, hydrogen is only very slightly soluble at room temperature and a distribution of the hydride phase linked to the thermal history of the sample predominates. Thus a fine acicular structure obtained from the β phase by quenching, enables an alloy having a good mechanical resistance to be conserved even when large quantities of hydrogen are present; the deformation capacity remains small. On the other hand, when the hydride phase separates the metallic phase into large grains, a very small elongation leads to a breakdown in mechanical resistance. (author) [fr

  14. The solubility of hydrogen and deuterium in alloyed, unalloyed and impure plutonium metal

    Energy Technology Data Exchange (ETDEWEB)

    Richmond, Scott [Los Alamos National Laboratory; Bridgewater, Jon S [Los Alamos National Laboratory; Ward, John W [Los Alamos National Laboratory; Allen, Thomas A [Los Alamos National Laboratory

    2009-01-01

    Pressure-Composition-Temperature (PCT) data are presented for the plutonium-hydrogen (Pu-H) and plutonium-deuterium (Pu-D) systems in the solubility region up to terminal solubility (precipitation of PuH{sub 2}). The heats of solution for PuH{sub s} and PuD{sub s} are determined from PCT data in the ranges 350-625 C for gallium alloyed Pu and 400-575 C for unalloyed Pu. The solubility of high purity plutonium alloyed with 2 at.% gallium is compared to high purity unalloyed plutonium. Significant differences are found in hydrogen solubility for unalloyed Pu versus gallium alloyed Pu. Differences in hydrogen solubility due to an apparent phase change are observable in the alloyed and unalloyed solubilities. The effect of iron impurities on Pu-Ga alloyed Pu is shown via hydrogen solubility data as preventing complete homogenization.

  15. The solubility of hydrogen and deuterium in alloyed, unalloyed and impure plutonium metal

    International Nuclear Information System (INIS)

    Richmond, S; Bridgewater, J S; Ward, J W; Allen, T H

    2010-01-01

    Pressure-Composition-Temperature (PCT) data are presented for the plutonium-hydrogen (Pu-H) and plutonium-deuterium (Pu-D) systems in the solubility region up to terminal solubility (precipitation of PuH 2 ). The heats of solution for PuH S and PuD S are determined from PCT data in the ranges 350-625 deg. C for gallium alloyed Pu and 400-575 deg. C for unalloyed Pu. The solubility of high purity plutonium alloyed with 2 at.% gallium is compared to high purity unalloyed plutonium. Significant differences are found in hydrogen solubility for unalloyed Pu versus gallium alloyed Pu. Differences in hydrogen solubility due to an apparent phase change are observable in the alloyed and unalloyed solubilities. The effect of iron impurities on Pu-Ga alloyed Pu is shown via hydrogen solubility data as preventing complete homogenization.

  16. The study on binary Mg-Co hydrogen storage alloys with BCC phase

    International Nuclear Information System (INIS)

    Zhang Yao; Tsushio, Yoshinori; Enoki, Hirotoshi; Akiba, Etsuo

    2005-01-01

    Novel Mg-Co binary alloys were successfully synthesized by mechanical alloying. These alloys were studied by X-ray diffraction (XRD), transmission electron micrograph (TEM), pressure-composition-isotherms measurements (P-C-T) and differential scanning calorimetry (DSC). Both XRD Rietveld analysis and TEM observation confirmed that these binary alloys contain BCC phase and that the BCC phase existed in the range from 37 to 80 at.% Co. The lattice parameter of the BCC phase increased with the increase of the Co content from 37 to 50 at.%. When the Co content reached 50 at.%, the lattice parameter reached a maximum value, and then turned to decrease gradually with further increase of the Co content. Most of Mg-Co BCC alloys absorbed hydrogen at 373 K under 6 MPa of hydrogen pressure. The Mg 60 Co 40 alloy showed the highest hydrogen absorption capacity, about 2.7 mass% hydrogen. However, all the Mg-Co alloys studied did not desorb hydrogen at 373 K. By means of DSC measurements and in situ XRD analysis, it was found that under 4 MPa hydrogen atmosphere, Mg 50 Co 50 alloy transformed from BCC solid solution to Mg 2 CoH 5 tetragonal hydride at 413 K

  17. Determination of the gaseous hydrogen ductile-brittle transition in copper-nickel alloys

    Science.gov (United States)

    Parr, R. A.; Johnston, M. H.; Davis, J. H.; Oh, T. K.

    1985-01-01

    A series of copper-nickel alloys were fabricated, notched tensile specimens machined for each alloy, and the specimens tested in 34.5 MPa hydrogen and in air. A notched tensile ratio was determined for each alloy and the hydrogen environment embrittlement (HEE) determined for the alloys of 47.7 weight percent nickel to 73.5 weight percent nickel. Stacking fault probability and stacking fault energies were determined for each alloy using the x ray diffraction line shift and line profiles technique. Hydrogen environment embrittlement was determined to be influenced by stacking fault energies; however, the correlation is believed to be indirect and only partially responsible for the HEE behavior of these alloys.

  18. Compatibility between vandium-base alloys and flowing lithium: Partitioning of hydrogen at elevated temperatures

    International Nuclear Information System (INIS)

    Hull, A.B.; Chopra, O.K.; Loomis, B.; Smith, D.

    1989-12-01

    A major concern in fusion reactor design is possible hydrogen-isotope-induced embrittlement of structural alloys in the neutron environment expected in these reactors. Hydrogen fractionation occurs between lithium and various refractory metals according to a temperature-dependent distribution coefficient, K H , that is defined as the ration of the hydrogen concentration in the metallic specimen to that in the liquid lithium. In the present work, K H was determined for pure vanadium and several binary and ternary alloys, and the commercial Vanstar 7. Hydrogen distribution studies were performed in an austenitic steel forced-circulation lithium loop. Equilibrium concentrations of hydrogen in vanadium-base alloys exposed to flowing lithium at temperatures of 350 to 550 degree C were measured by inert gas fusion techniques and residual gas analysis. Thermodynamic calculations are consistent with the effect of chromium and titanium in the alloys on the resultant hydrogen fractionation. Experimental and calculated results indicate that K H values are very low; i.e., the hydrogen concentrations in the lithium-equilibrated vanadium-base alloy specimens are about two orders of magnitude lower than those in the lithium. Because of this low distribution coefficient, embrittlement of vanadium alloys by hydrogen in lithium would not be expected. 15 refs., 5 figs., 4 tabs

  19. Determination of hydrogen in uranium-niobium-zirconium alloy by inert-gas fusion

    International Nuclear Information System (INIS)

    Carden, W.F.

    1979-12-01

    An improved method has been developed using inert-gas fusion for determining the hydrogen content in uranium-niobium-zirconium (U-7.5Nb-2.5Zr) alloy. The method is applicable to concentrations of hydrogen ranging from 1 to 250 micrograms per gram and may be adjusted for analysis of greater hydrogen concentrations. Hydrogen is determined using a hydrogen determinator. The limit of error for a single determination at the 95%-confidence level (at the 3.7-μg/g-hydrogen level) is +-1.4 micrograms per gram hydrogen

  20. Electrochemical hydrogen storage alloys and batteries fabricated from Mg containing base alloys

    Science.gov (United States)

    Ovshinsky, Stanford R.; Fetcenko, Michael A.

    1996-01-01

    An electrochemical hydrogen storage material comprising: (Base Alloy).sub.a M.sub.b where, Base Alloy is an alloy of Mg and Ni in a ratio of from about 1:2 to about 2:1, preferably 1:1; M represents at least one modifier element chosen from the group consisting of Co, Mn, Al, Fe, Cu, Mo, W, Cr, V, Ti, Zr, Sn, Th, Si, Zn, Li, Cd, Na, Pb, La, Mm, and Ca; b is greater than 0.5, preferably 2.5, atomic percent and less than 30 atomic percent; and a+b=100 atomic percent. Preferably, the at least one modifier is chosen from the group consisting of Co, Mn, Al, Fe, and Cu and the total mass of the at least one modifier element is less than 25 atomic percent of the final composition. Most preferably, the total mass of said at least one modifier element is less than 20 atomic percent of the final composition.

  1. Determination of activation energy of hydrogen diffusion in Zr-2.5%Nb alloy

    International Nuclear Information System (INIS)

    Chandra, Komal; Kulkarni, A.S.; Ramanjaneyulu, P.S.; Yadav, C.S.; Saxena, M.K.; Tomar, B.S.; Ramakumar, K.L.; Sunil, Sourav; Singh, R.N.

    2013-01-01

    The present paper describes the study on the determination of diffusion coefficient of hydrogen in Zr-2.5%Nb alloy. Hydrogen was charged on Zr-2.5% Nb alloy electrolytically. After annealing at required temperature, hydrogen concentration at various depths from the charged end was determined employing hot vacuum extraction-quadrupole mass spectrometer (HVE-QMS). The depth profile was used to obtain the diffusion coefficient employing Fick's second law of diffusion. From the Arrhenius relation between diffusion coefficient and temperature, activation energy of hydrogen diffusion was calculated. (author)

  2. Permeability of hydrogen isotopes through Pd-Ag membrane

    International Nuclear Information System (INIS)

    Yoshida, Hiroshi

    1981-01-01

    This paper represents the permeabilities, diffusion coefficients and isotope effects for hydrogen and deuterium through Pd-25 wt.% Ag alloy tubes The feed gas H 2 or D 2 flowing into the permeation cell was preheated before it reached to the outer surface of the permeation tube made of palladium-silver alloy. Permeation time lag method could be successfully carried out with the present apparatus to measure both permeability and diffusion coefficient. The square-root pressure dependence for the permeation of hydrogen isotopes was observed. The observed systematic temperature dependence indicates that the approximation of the Arrhenius' relation was effective within this experimental conditions. Some tendency of permeation fluxes in relation to the reciprocal temperature, 1/T, was seen. The permeability ratio was larger than the square root of isotopic mass ratio, and it decreased with temperature rise. On the contrary, the diffusion coefficient ratio was much smaller than the square root of isotopic mass ratio. (Kato, T.)

  3. Hydrogen isotopes mobility and trapping in V-Cr-Ti alloys

    International Nuclear Information System (INIS)

    Budylkin, N.; Voloschin, L.; Mironova, E.; Riazantseva, N.; Tebus, V.

    1996-01-01

    In the last years the V-Ti-Cr alloys were considered as candidate materials for different structures of fusion reactors (blanket, first wall, divertor and so on) due to their advantages over other structure materials. Mobility and trapping parameters of hydrogen are essential characteristics for an assessment of using the V-Ti-Cr alloys in FR. In this paper: hydrogen problems for V-Ti-Cr alloys are formulated; V-H system data base is analyzed; study results of the hydrogen mobility and trapping in V-4Ti-4Cr and V-10Ti-5Cr alloys are given; the classification of V-alloys as radioactive waste according to the Russian Federation waste management rules is developed taking into account the residual amount of tritium ('inventory'). (orig.)

  4. In-pile tritium permeation experiment

    International Nuclear Information System (INIS)

    Longhurst, G.R.; Miller, L.G.; Watts, K.D.; Kershner, C.J.; Rogers, M.L.

    1982-01-01

    The experiments in progress are examining various aspects of the permeation of hydrogen isotopes through fusion materials. Of particular importance will be the measurement of permeation due to ion implantation in the presence of a neutron radiation field. Theoretical and early experimental results for these experiments have suggested that sufficient tritium will permeate fusion reactor interior structures that development of a permeation barrier will be needed. (orig.)

  5. In-pile tritium permeation experiment

    Energy Technology Data Exchange (ETDEWEB)

    Longhurst, G.R.; Miller, L.G.; Watts, K.D. (Idaho National Engineering Lab., Idaho Falls (USA)); Kershner, C.J.; Rogers, M.L. (Monsanto Research Corp., Miamisburg, OH (USA). Mound Facility)

    The experiments in progress are examining various aspects of the permeation of hydrogen isotopes through fusion materials. Of particular importance will be the measurement of permeation due to ion implantation in the presence of a neutron radiation field. Theoretical and early experimental results for these experiments have suggested that sufficient tritium will permeate fusion reactor interior structures that development of a permeation barrier will be needed.

  6. Effect of hydrogen and oxygen content on the embrittlement of Zr alloys

    International Nuclear Information System (INIS)

    Griger, A.; Hozer, Z.; Matus, L.; Vasaros, L.; Horvath, M.

    2001-01-01

    An experimental study is carried out in the KFKI Atomic Energy Research Institute in order to clear up the role of oxidation and hydrogen uptake in the embrittlement process. Russian E110 type Zr1%Nb and Zircaloy-4 claddings are used as test materials. The differences between the properties of two alloys are examined. The sample preparation covered the following cases: oxidation in Ar+O 2 atmosphere; hydrogen uptake of as received and pre-oxidised samples (in Ar+O 2 atmosphere); oxidation in steam. The oxidation in Ar+O 2 and the subsequent hydrogen uptake procedure make possible the production of samples with well-characterized hydrogen and oxygen content. Corrosion treated ring samples of 8 mm height are examined in ring compression tests. The force-deformation curves are recorded and the crushing force and deformation are determined. The relative deformation is used for the characterisation of embrittlement level. The results of experiments provide detailed information about the effect of hydrogen and oxygen content on the embrittlement of zirconium alloys. The conclusions are: 1) hydrogen seems to play a more important role in the embrittlement of zirconium alloys than oxygen; 2) the Zircaloy-4 alloy becomes brittle at lower hydrogen content than the Zr1%Nb; 3) under steam oxidation conditions the Zr1%Nb alloy takes up much more hydrogen and becomes more brittle than the Zircaloy-4

  7. Hydrogen and deuterium transport and inventory parameters in a Cu-0.65Cr-0.08Zr alloy for fusion reactor applications

    International Nuclear Information System (INIS)

    Serra, E.; Perujo, A.

    1998-01-01

    A time dependent permeation method has been used to measure the transport and inventory parameters of hydrogen and deuterium in the precipitation hardened (PH) Cu-0.65 wt% Cr-0.08 wt% Zr alloy (ELBRODUR HF). The measurements cover the temperature range from 553 to 773 K using a hydrogen or deuterium pressure in the range 1-100 kPa. The permeabilities, diffusivities and Sieverts' constant values for ELBRODUR obtained in this work were about 2 time higher, 2 times lower and between 3 and 10 time higher respectively to that of Cu (F. Reiter et al., 1993) in the temperature range studied. Using the measured diffusivities and Sieverts' constant values for H 2 and D 2 and a quantum-mechanical model, an extrapolation for tritium is also presented. (orig.)

  8. Review of theoretical conceptions on regimes of oxidation and hydrogen pickup in Zr-alloys

    International Nuclear Information System (INIS)

    Likhanskii, V.; Evdokimov, I.

    2008-01-01

    In this paper the following issues are presented: 1) Experimental observations published in the journals on corrosion regimes of zirconium alloys of various compositions both for ex-pile oxidation experiments and for in-pile operating conditions of the materials. Factors experimentally stated on the effect of alloying composition, microstructure and texture on the rate of uniform corrosion and susceptibility of alloys to nodular corrosion. 2) Phenomenological models existing in publications, which describe conditions of uniform and nodular corrosion for Zr-alloys of various composition and microstructures, effect of irradiation and oxidizing medium; 3) Experimental data and phenomenological models describing regimes of hydrogen absorption in zirconium alloys; 4) Examples of application of physical models in explaining regimes, peculiarities of oxidation and hydrogen pickup for zirconium claddings of various alloying composition and microstructure

  9. Penetration of hydrogen isotopes through EhI 698 alloy at high pressure and temperature

    International Nuclear Information System (INIS)

    Bystritskij, V.M.; Voznyak, Ya.; Granovskij, V.B.

    1986-01-01

    The paper deals with investigations of the process of hydrogen and deuterium penetration through the high-temperature alloy EhI-698 at a pressure up to 1 kbar and temperature up to 1050 K. Parameters of the process obey Sieverts's law and can be described by Arrenius's and Vant-Goff's equations. The obtained results lead to a conclusion that the alloy EhI-698 is good for vessels to be employed in hydrogen media

  10. Stress corrosion mechanisms of alloy-600 polycrystals and monocrystals in primary water: effect of hydrogen

    International Nuclear Information System (INIS)

    Foct, F.

    1999-01-01

    The aim of this study is to identify the mechanisms involved in Alloy 600 primary water stress corrosion cracking. Therefore, this work is mainly focussed on the two following points. The first one is to understand the influence of hydrogen on SCC of industrial Alloy 600 and the second one is to study the crack initiation and propagation on polycrystals and single crystals. A cathodic potential applied during slow strain rate tests does not affect crack initiation but increases the slow crack growth rate by a factor 2 to 5. Cathodic polarisation, cold work and 25 cm 3 STP/kg hydrogen content increase the slow CGR so that the K ISCC (and therefore fast CGR) is reached. The influence of hydrogenated primary water has been studied for the first time on Alloy 600 single crystals. Cracks cannot initiate on tensile specimens but they can propagate on pre-cracked specimens. Transgranular cracks present a precise crystallographic aspect which is similar to that of 316 alloy in MgCl 2 solutions. Moreover, the following results improve the description of the cracking conditions. Firstly, the higher the hydrogen partial pressure, the lower the Alloy 600 passivation current transients. Since this result is not correlated with the effect of hydrogen on SCC, cracking is not caused by a direct effect of dissolved hydrogen on dissolution. Secondly, hydrogen embrittlement of Alloy 600 disappears at temperatures above 200 deg.C. Thirdly, grain boundary sliding (GBS) does not directly act on SCC but shows the mechanical weakness of grain boundaries. Regarding the proposed models for Alloy 600 SCC, it is possible to draw the following conclusions. Internal oxidation or absorbed hydrogen effects are the most probable mechanisms for initiation. Dissolution, internal oxidation and global hydrogen embrittlement models cannot explain crack propagation. On the other hand, the Corrosion Enhanced Plasticity Model gives a good description of the SCC propagation. (author)

  11. Separation of Hydrogen Isotopes by Palladium Alloy Membranes Separator

    International Nuclear Information System (INIS)

    Jiangfeng, S.; Deli, L.; Yifu, X.; Congxian, L.; Zhiyong, H.

    2007-01-01

    Full text of publication follows: Separation of hydrogen isotope with palladium alloy membranes is one of the promising methods for hydrogen isotope separation. It has several advantages, such as high separation efficiency, smaller tritium inventory, simple separation device, ect. Limited by the manufacture of membrane and cost of gas transportation pump, this method is still at the stage of conceptual study. The relationship between separation factors and temperatures, feed gas components, split ratios have not been researched in detail, and the calculated results of cascade separation have not been validated with experimental data. In this thesis, a palladium alloy membrane separator was designed to further study its separation performance between H 2 and D 2 . The separation factor of the single stage was affected by the temperature, the feed gas component, the split ratio and the gas flow rate, etc. The experimental results showed that the H 2 -D 2 separation factor decreased with the increasing of temperature. On the temperature from 573 K to 773 K, when the feed rate was 5 L/min, the separation factor of 66.2%H 2 - 33.8%D 2 decreased from 2.09 to 1.85 when the split ratio was 0.1 and from 1.74 to 1.52 when the split ratio was 0.2.The separation factor also decreased with the increasing of split ratio. At 573 K and the feed rate of 5 L/min, the separation factor of 15.0%H 2 and 85.0%D 2 decreased from 2.43 to 1.35 with the increasing of split ratio from 0.050 to 0.534,and for 66.2%H 2 -33.8%D 2 , the separation factor decreased from 2.87 to 1.30 with the increasing of split ratio from 0.050 to 0.688. When the separation factor was the biggest, the flow rate of feed gas was in a perfect value. To gain a best separation performance, perfect flow rate, lower temperature and reflux ratio should be chosen. (authors)

  12. Hydrogen absorption-desorption properties of UZr0.29 alloy

    International Nuclear Information System (INIS)

    Shuai Maobing; Su Yongjun; Wang Zhenhong; Zhang Yitao

    2001-01-01

    Hydrogen absorption-desorption properties of UZr 0.29 alloy are investigated in detail at hydrogen pressures up to 0.4 MPa and over the temperature range of 300 to 723 K. It absorbs hydrogen up to 2.3 H atoms per F.U. (formula unit) by only one-step reaction and hence each desorption isotherm has a single plateau over nearly the whole hydrogen composition range. The enthalpy and entropy changes of the dissociation reaction are of -78.9 kJ·mol -1 H 2 and 205.3 J·(K·mol H 2 ) -1 , respectively. The alloy shows high durability against powdering upon hydrogenation and may have good heat conductivity. It is predicted that UZr 0.29 alloy may be a suitable material for tritium treatment and storage

  13. Nanoscale microstructure effects on hydrogen behavior in rapidly solidified aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Tashlykova-Bushkevich, Iya I. [Belarusian State University of Informatics and Radioelectronics, Minsk (Belarus)

    2015-12-31

    The present work summarizes recent progress in the investigation of nanoscale microstructure effects on hydrogen behavior in rapidly solidified aluminum alloys foils produced at exceptionally high cooling rates. We focus here on the potential of modification of hydrogen desorption kinetics in respect to weak and strong trapping sites that could serve as hydrogen sinks in Al materials. It is shown that it is important to elucidate the surface microstructure of the Al alloy foils at the submicrometer scale because rapidly solidified microstructural features affect hydrogen trapping at nanostructured defects. We discuss the profound influence of solute atoms on hydrogen−lattice defect interactions in the alloys. with emphasis on role of vacancies in hydrogen evolution; both rapidly solidified pure Al and conventionally processed aluminum samples are considered.

  14. Effect of trapping and temperature on the hydrogen embrittlement susceptibility of alloy 718

    Energy Technology Data Exchange (ETDEWEB)

    Galliano, Florian; Andrieu, Eric; Blanc, Christine; Cloue, Jean-Marc; Connetable, Damien; Odemer, Gregory, E-mail: gregory.odemer@ensiacet.fr

    2014-08-12

    Ni-based alloy 718 is widely used to manufacture structural components in the aeronautic and nuclear industries. Numerous studies have shown that alloy 718 may be sensitive to hydrogen embrittlement. In the present study, the susceptibilities of three distinct metallurgical states of alloy 718 to hydrogen embrittlement were investigated to identify both the effect of hydrogen trapping on hydrogen embrittlement and the role of temperature in the hydrogen-trapping mechanism. Cathodic charging in a molten salt bath was used to saturate the different hydrogen traps of each metallurgical state. Tensile tests at different temperatures and different strain rates were carried out to study the effect of hydrogen on mechanical properties and failure modes, in combination with hydrogen content measurements. The results demonstrated that Ni-based superalloy 718 was strongly susceptible to hydrogen embrittlement between 25 °C and 300 °C, and highlighted the dominant roles played by the hydrogen solubility and the hydrogen trapping on mechanical behavior and fracture modes.

  15. Study of the controllable reactivity of aluminum alloys and their promising application for hydrogen generation

    International Nuclear Information System (INIS)

    Fan Meiqiang; Sun Lixian; Xu Fen

    2010-01-01

    The hydrolysis performances of two aluminum alloys are investigated as their reactivity can be controlled via the different additives. The additive of NaCl has the positive effect to improve the hydrolysis properties of the aluminum alloys with quicker hydrolysis kinetic and lower hydrolysis temperature. For examples, in 6 min of hydrolysis reaction, the Al-5 wt%Hg-5 wt%NaCl can produce 971 mL g -1 hydrogen, higher than 917 mL g -1 hydrogen from Al-10 wt%Hg alloy. The Al-In-NaCl alloy has lower hydrolysis temperature about 10 K than that of Al-In alloy. Meanwhile, the reactivity of Al alloys can be improved or reduced via the additive metals. It can be found that the additive cadmium can reduce the reactivity of Al-Hg alloy. The Al-Hg-Cd alloys can keep good stability at the moist atmosphere below 343 K and have excellent hydrolysis performance around 343-373 K. The debased reactivity of Al-Hg-Cd composite comes from the formation of CdHg 2 compounds in the milling process. But the additive Zn and Ga doped into the Al-In-NaCl alloys can quickly increase the reactivity of the alloy which can quickly react with water at room temperature and have high hydrogen yield up to the theoretic value. Therefore, it is a promising possibility that the controllable reactivity of aluminum alloys can be obtained through the different additive according to the practical request, and the Al alloys can produce pure hydrogen for the fuel cell via the hydrolysis reaction.

  16. Improved hydrogen absorption and desorption kinetics of magnesium-based alloy via addition of yttrium

    Science.gov (United States)

    Yang, Tai; Li, Qiang; Liu, Ning; Liang, Chunyong; Yin, Fuxing; Zhang, Yanghuan

    2018-02-01

    Yttrium (Y) is selected to modify the microstructure of magnesium (Mg) to improve the hydrogen storage performance. Thereby, binary alloys with the nominal compositions of Mg24Yx (x = 1-5) are fabricated by inexpensive casting technique. Their microstructure and phase transformation during hydriding and dehydriding process are characterized by using X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy analysis. The isothermal hydrogen absorption and desorption kinetics are also measured by a Sievert's-type apparatus at various temperatures. Typical multiphase structures of binary alloy can be clearly observed. All of these alloys can reversibly absorb and desorb large amount of hydrogen at proper temperatures. The addition of Y markedly promotes the hydrogen absorption kinetics. However, it results in a reduction of reversible hydrogen storage capacity. A maximum value of dehydrogenation rate is observed with the increase of Y content. The Mg24Y3 alloy has the optimal desorption kinetic performance, and it can desorb about 5.4 wt% of hydrogen at 380 °C within 12 min. Combining Johnson-Mehl-Avrami kinetic model and Arrhenius equation, the dehydrogenation activation energy of the alloys are evaluated. The Mg24Y3 alloy also has the lowest dehydrogenation activation energy (119 kJ mol-1).

  17. An alternate mathematical approach to recover hydrogen with high permeate purity from gas streams of small-medium level oil refineries

    International Nuclear Information System (INIS)

    Ahsan, M.; Hussain, A.

    2013-01-01

    Gas separation processes play a vital role in many industries like hydrogen recovery, air separation, natural gas dehydration. Membrane based gas separation processes offer a great potential for these industrial applications because of their environmental friendliness, energy efficiency and ease of scale up. Mathematical modeling of membrane based gas separation process can help to predict the performance of such separation processes. In this study, a numerical method is proposed by comparing different numerical techniques which are used to solve model equations of co-current flow. Numerical methods such as Bogacki-Shampine method, Dormand-Prince method, Adams-Bashforth-Moulton method, numerical differentiation formulas, modified Rosenbrock formula of order 2, Trapezoidal rule with free interpolant and Trapezoidal rule with backward difference formula of order 2 are used to solve the system of coupled nonlinear differential equations. This approach is used for the first time in a multicomponent membrane based gas separation process. This technique requires least computational time, improved solution stability and has been validated for the separation of hydrogen from multicomponent gas mixture. This numerical technique helps to predict the concentration of hydrogen in reject (retentate) and permeate streams. The simulation results show good agreement with experimental data. (author)

  18. The development of hydrogen storage electrode alloys for nickel hydride batteries

    Science.gov (United States)

    Hong, Kuochih

    The development of hydrogen storage electrode alloys in the 1980s resulted in the birth and growth of the rechargeable nickel hydride (Ni/MH) battery. In this paper we describe briefly a semi-empirical electrochemical/thermodynamic approach to develop/screen a hydrogen storage alloy for electrochemical application. More specifically we will discuss the AB x Ti/Zr-based alloys. Finally, the current state of the Ni/MH batteries including commercial manufacture processes, cell performance and applications is given.

  19. The Current Status of Hydrogen Storage Alloy Development for Electrochemical Applications

    Science.gov (United States)

    Young, Kwo-hsiung; Nei, Jean

    2013-01-01

    In this review article, the fundamentals of electrochemical reactions involving metal hydrides are explained, followed by a report of recent progress in hydrogen storage alloys for electrochemical applications. The status of various alloy systems, including AB5, AB2, A2B7-type, Ti-Ni-based, Mg-Ni-based, BCC, and Zr-Ni-based metal hydride alloys, for their most important electrochemical application, the nickel metal hydride battery, is summarized. Other electrochemical applications, such as Ni-hydrogen, fuel cell, Li-ion battery, air-metal hydride, and hybrid battery systems, also have been mentioned. PMID:28788349

  20. Semiempirical quantum model approach for hydrogen adsorption in ZrNi alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Bin-Hao, E-mail: binhao17@gmail.com [Department of Energy Application Engineering, Far East University, No. 49, Zhonghua Rd., Xinshi Dist., Tainan City 74448, Taiwan, ROC (China); Huang, Chien-Chung [Department of Hydrogen Energy and Fuel Cells, Green Energy and Eco-Technology Center, ITRI, No. 49, Zhonghua Rd., Xinshi Dist., Tainan City 74448, Taiwan, ROC (China); Yeh, Yen-Lian; Jang, Ming-Jyi [Department of Automation and Control Engineering, Far East University, No. 49, Zhonghua Rd., Xinshi Dist., Tainan City 74448, Taiwan, ROC (China)

    2013-12-15

    Highlights: •The hydrogen diffusion behavior in solid ZrNi alloy performs clearly by MD. •Shear and Young’s modulus agree with the experiment study very well. •Current model can apply to hydrogen-tech material development. -- Abstract: Hydrogen storage is an important topic because of its relevance to the future energy economy. Hydrogen diffusivity in materials plays an important role in hydrogen technology both for hydrogen separation and hydrogen storage. To clarify the mechanism of the rate-controlling step, diffusion mechanism of hydrogen in metallic materials is studied by molecular dynamics method. This study performs semi-empirical-quantum molecular dynamic simulations in order to clarify hydrogen atom diffusion behavior in ZrNi alloys materials. We investigate the mechanical properties change associated with temperature variation for ZrNi base alloys and also consider the influence of materials micro-structure change of hydrogen diffusion. Finally, current work presents a theoretically prediction of dynamical diffusion coefficient to compare diffusion kinetics of crystalline and amorphous structure.

  1. Suitability of Tophet C-Alloy 52/Kovar components to hydrogen environments

    International Nuclear Information System (INIS)

    Gebhart, J.M.; Kelly, M.D.

    1976-01-01

    The suitability of Tophet C-Alloy 52/Kovar weldments to hydrogen embrittlement were investigated because of their potential as candidate materials in fabrication of minaturized initiators for pyrotechnics. Cathodic charged samples were statically loaded for extended periods of time resulting in no load failures and in ductile fracture surfaces indicating resistance to hydrogen embrittlement. 20 figures

  2. Hydrogen storage performance of Ti-V-based BCC phase alloys with various Fe content

    International Nuclear Information System (INIS)

    Yu, X.B.; Feng, S.L.; Wu, Z.; Xia, B.J.; Xu, N.X.

    2005-01-01

    The effect of Fe content on hydrogen storage characteristics of Ti-10Cr-18Mn-(32-x)V-xFe (x = 0, 2, 3, 4, 5) alloys has been investigated at 353 K. The X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images of the alloys present BCC and C14 two-phase structures for all of the Fe-containing alloys. With the increasing Fe content, the lattice parameters of the BCC phase decrease, which results in an increase of the hydrogen desorption plateau pressure of the alloys. Among the studied alloys, Ti-10Cr-18Mn-27V-5Fe alloy exhibits the smallest PCT plateau slope and a more suitable plateau pressure (0.1 MPa equ <1 MPa). The maximum and effective capacities of the alloy are 3.32 wt.% and 2.26 wt.%, respectively, which are higher than other reported Fe-containing BCC phase alloys. In addition, the V/Fe ratio in this alloy is close to that of (VFe) alloy, whose cost is much lower than that of pure V

  3. Properties of Mg-Al alloys in relation to hydrogen storage

    DEFF Research Database (Denmark)

    Andreasen, A.

    2005-01-01

    storage e.g. in stationary applications. In this report the properties of Mg-Al alloys are reviewed in relation to solid state hydrogen storage. Alloying with Al reduces the hydrogen capacity since Al doesnot form a hydride under conventional hydriding conditions, however both the thermodynamical......Magnesium theoretically stores 7.6 wt. % hydrogen, although it requires heating to above 300 degrees C in order to release hydrogen. This limits its use for mobile application. However, due to its low price and abundance magnesium should still beconsidered as a potential candidate for hydrogen...... properties (lower desorption temperature), and kinetics of hydrogenation/dehydrogenation are improved. In addition to this, the low price of the hydride isretained along with improved heat transfer properties and improved resistance towards oxygen contamination....

  4. Properties of MgAl alloys in relation to hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Andreasen, Anders

    2005-08-01

    Magnesium theoretically stores 7.6 wt. % hydrogen, although it requires heating to above 300 degrees C in order to release hydrogen. This limits its use for mobile application. However, due to its low price and abundance magnesium should still be considered as a potential candidate for hydrogen storage e.g. in stationary applications. In this report the properties of Mg-Al alloys are reviewed in relation to solid state hydrogen storage Alloying with Al reduces the hydrogen capacity since Al does not form a hydride under conventional hydriding conditions, however both the thermodynamical properties (lower desorption temperature), and kinetics of hydrogenation/dehydrogenation are improved. In addition to this, the low price of the hydride is retained along with improved heat transfer properties and improved resistance towards oxygen contamination. (au)

  5. Hydrogen storage in binary and ternary Mg-based alloys. A comprehensive experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Kalisvaart, W.P.; Harrower, C.T.; Haagsma, J.; Zahiri, B.; Luber, E.J.; Ophus, C.; Miltin, D. [Alberta Univ., Edmonton (Canada); Poirier, E.; Fritzsche, H. [Canadian Neutron Beam Centre, Chalk River, ON (Canada)

    2010-07-01

    This study focuses on hydrogen sorption properties of cosputtered 1.5 micrometer thick Mg-based films with Al, Fe and Ti as alloying elements. We show that ternary Mg-Al-Ti and Mg-Fe-Ti alloys in particular display remarkable sorption behavior: at 200 C, the films are capable of absorbing 4-6 wt.% hydrogen in seconds, and desorbing in minutes. Furthermore, this sorption behavior is stable for over 100 ab- and desorption cycles for Mg-Al-Ti and Mg-Fe-Ti alloys. No degradation in capacity or kinetics is observed. Based on these observations, some general design principles for Mg-based hydrogen storage alloys are suggested. For Mg-Fe-Ti, encouraging preliminary results on multilayered systems are also presented. (orig.)

  6. Hydrogen permeation in asymmetric La28-xW4 + xO54 + 3x/2 membranes

    DEFF Research Database (Denmark)

    Gil, Vanesa; Gurauskis, Jonas; Kjølseth, Christian

    2013-01-01

    Asymmetric supported La28 - xW4 + xO 54 + 3x/2 (La/W ≈ 5.6) membranes were investigated for their hydrogen permeation properties as a function of temperature and feed gas conditions. Dense membranes of thickness 25-30 μm supported on substrates with 25 and 40 vol.% porosity were compared. Above 850...

  7. Hydrogen embrittlement: the game changing factor in the applicability of nickel alloys in oilfield technology

    Science.gov (United States)

    Sarmiento Klapper, Helmuth; Klöwer, Jutta; Gosheva, Olesya

    2017-06-01

    Precipitation hardenable (PH) nickel (Ni) alloys are often the most reliable engineering materials for demanding oilfield upstream and subsea applications especially in deep sour wells. Despite their superior corrosion resistance and mechanical properties over a broad range of temperatures, the applicability of PH Ni alloys has been questioned due to their susceptibility to hydrogen embrittlement (HE), as confirmed in documented failures of components in upstream applications. While extensive work has been done in recent years to develop testing methodologies for benchmarking PH Ni alloys in terms of their HE susceptibility, limited scientific research has been conducted to achieve improved foundational knowledge about the role of microstructural particularities in these alloys on their mechanical behaviour in environments promoting hydrogen uptake. Precipitates such as the γ', γ'' and δ-phase are well known for defining the mechanical and chemical properties of these alloys. To elucidate the effect of precipitates in the microstructure of the oil-patch PH Ni alloy 718 on its HE susceptibility, slow strain rate tests under continuous hydrogen charging were conducted on material after several different age-hardening treatments. By correlating the obtained results with those from the microstructural and fractographic characterization, it was concluded that HE susceptibility of oil-patch alloy 718 is strongly influenced by the amount and size of precipitates such as the γ' and γ'' as well as the δ-phase rather than by the strength level only. In addition, several HE mechanisms including hydrogen-enhanced decohesion and hydrogen-enhanced local plasticity were observed taking place on oil-patch alloy 718, depending upon the characteristics of these phases when present in the microstructure. This article is part of the themed issue 'The challenges of hydrogen and metals'.

  8. Enhanced Hydrogen Storage Kinetics of Nanocrystalline and Amorphous Mg₂Ni-type Alloy by Melt Spinning.

    Science.gov (United States)

    Zhang, Yang-Huan; Li, Bao-Wei; Ren, Hui-Ping; Li, Xia; Qi, Yan; Zhao, Dong-Liang

    2011-01-18

    Mg₂Ni-type Mg₂Ni 1-x Co x (x = 0, 0.1, 0.2, 0.3, 0.4) alloys were fabricated by melt spinning technique. The structures of the as-spun alloys were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The hydrogen absorption and desorption kinetics of the alloys were measured by an automatically controlled Sieverts apparatus. The electrochemical hydrogen storage kinetics of the as-spun alloys was tested by an automatic galvanostatic system. The results show that the as-spun (x = 0.1) alloy exhibits a typical nanocrystalline structure, while the as-spun (x = 0.4) alloy displays a nanocrystalline and amorphous structure, confirming that the substitution of Co for Ni notably intensifies the glass forming ability of the Mg₂Ni-type alloy. The melt spinning treatment notably improves the hydriding and dehydriding kinetics as well as the high rate discharge ability (HRD) of the alloys. With an increase in the spinning rate from 0 (as-cast is defined as spinning rate of 0 m/s) to 30 m/s, the hydrogen absorption saturation ratio () of the (x = 0.4) alloy increases from 77.1 to 93.5%, the hydrogen desorption ratio () from 54.5 to 70.2%, the hydrogen diffusion coefficient (D) from 0.75 × 10 - 11 to 3.88 × 10 - 11 cm²/s and the limiting current density I L from 150.9 to 887.4 mA/g.

  9. Heat pump cycle by hydrogen-absorbing alloys to assist high-temperature gas-cooled reactor in producing hydrogen

    International Nuclear Information System (INIS)

    Satoshi, Fukada; Nobutaka, Hayashi

    2010-01-01

    A chemical heat pump system using two hydrogen-absorbing alloys is proposed to utilise heat exhausted from a high-temperature source such as a high-temperature gas-cooled reactor (HTGR), more efficiently. The heat pump system is designed to produce H 2 based on the S-I cycle more efficiently. The overall system proposed here consists of HTGR, He gas turbines, chemical heat pumps and reaction vessels corresponding to the three-step decomposition reactions comprised in the S-I process. A fundamental research is experimentally performed on heat generation in a single bed packed with a hydrogen-absorbing alloy that may work at the H 2 production temperature. The hydrogen-absorbing alloy of Zr(V 1-x Fe x ) 2 is selected as a material that has a proper plateau pressure for the heat pump system operated between the input and output temperatures of HTGR and reaction vessels of the S-I cycle. Temperature jump due to heat generated when the alloy absorbs H 2 proves that the alloy-H 2 system can heat up the exhaust gas even at 600 deg. C without any external mechanical force. (authors)

  10. Thermodynamic Tuning of Mg-Based Hydrogen Storage Alloys: A Review

    Science.gov (United States)

    Zhu, Min; Lu, Yanshan; Ouyang, Liuzhang; Wang, Hui

    2013-01-01

    Mg-based hydrides are one of the most promising hydrogen storage materials because of their relatively high storage capacity, abundance, and low cost. However, slow kinetics and stable thermodynamics hinder their practical application. In contrast to the substantial progress in the enhancement of the hydrogenation/dehydrogenation kinetics, thermodynamic tuning is still a great challenge for Mg-based alloys. At present, the main strategies to alter the thermodynamics of Mg/MgH2 are alloying, nanostructuring, and changing the reaction pathway. Using these approaches, thermodynamic tuning has been achieved to some extent, but it is still far from that required for practical application. In this article, we summarize the advantages and disadvantages of these strategies. Based on the current progress, finding reversible systems with high hydrogen capacity and effectively tailored reaction enthalpy offers a promising route for tuning the thermodynamics of Mg-based hydrogen storage alloys. PMID:28788353

  11. Beneficial effect of carbon on hydrogen desorption kinetics from Mg–Ni–In alloy

    International Nuclear Information System (INIS)

    Cermak, J.; Kral, L.

    2013-01-01

    Highlights: ► Beneficial effect of graphitic carbon was observed. ► The effect is optimal up to c opt . ► Above c opt , phase decomposition occurs. ► Indium in studied Mg–Ni-based alloys prevents oxidation. - Abstract: In the present paper, hydrogen desorption kinetics from hydrided Mg–Ni–In–C alloys was investigated. A chemical composition that substantially accelerates hydrogen desorption was found. It was observed that carbon improves the hydrogen desorption kinetics significantly. Its beneficial effect was found to be optimum close to the carbon concentration of about c C ≅ 5 wt.%. With this composition, stored hydrogen can be desorbed readily at temperatures down to about 485 K, immediately after hydrogen charging. This can substantially shorten the hydrogen charging/discharging cycle of storage tanks using Mg–Ni-based alloys as hydrogen storage medium. For higher carbon concentrations, unwanted phases precipitated, likely resulting in deceleration of hydrogen desorption and lower hydrogen storage capacity.

  12. Fabricating method of hydrogen absorbing alloy for alkali storage battery; Arukari chikudenchiyo suiso kyuzo gokin no seizo hoho

    Energy Technology Data Exchange (ETDEWEB)

    Tadokoro, M.

    1996-03-08

    There are many grain boundaries in spherical hydrogen absorbing alloy particles prepared by rapid solidification methods such as centrifugal spraying method and gas atomizing method, and heterogeneous strains are produced at boundaries. When hydrogen absorbing alloy with large heterogeneous strain is used for preparing electrodes, many cracks are produced in hydrogen absorbing alloy to cause pulverization in the charge and discharge cycles. This invention relates to heat treatment of hydrogen absorbing alloys having spherical shape, cannon ball shape, and egg-like shape prepared by rapid solidification method in moving conditions. By this heat treatment, mutual sintering of hydrogen absorbing alloy particles can be prevented. The methods for moving hydrogen absorbing alloy are vibration or rotation of the heat treatment container in which hydrogen absorbing alloy is held and agitation of hydrogen absorbing alloy powder. Furthermore, mutual sintering of hydrogen absorbing alloy is restricted to reduce homogeneous strain by heat treatment in the range from 700{degree}C to 1,100{degree}C. 3 figs., 6 tabs.

  13. Influence of alloying on hydrogen-assisted cracking and diffusible ...

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    moisture in the welding consumables which dissociate in the welding arc to form hydrogen and oxygen. The susceptibility of the weldment to HAC is assessed from the hydrogen diffused out from the weld after the welding is over. Hydrogen thus diffused out is referred to as diffusible hydrogen (HD) and is estimated from the ...

  14. Calculations of hydrogen diffusivity in Zr-based alloys: Influence of alloying elements and effect of stress

    International Nuclear Information System (INIS)

    Yu, J.; Jiang, C.; Zhang, Y.

    2017-01-01

    This report summarizes the progress on modeling hydrogen diffusivity in Zr-based alloys. The presence of hydrogen (H) can detrimentally affect the mechanical properties of many metals and alloys. To mitigate these detrimental effects requires fundamental understanding of the thermodynamics and kinetics governing H pickup and hydride formation. In this work, we focus on H diffusion in Zr-based alloys by studying the effects of alloying elements and stress, factors that have been shown to strongly affect H pickup and hydride formation in nuclear fuel claddings. A recently developed accelerated kinetic Monte Carlo method is used for the study. It is found that for the alloys considered here, H diffusivity depends weakly on composition, with negligible effect at high temperatures in the range of 600-1200 K. Therefore, the small variation in compositions of these alloys is likely not a major cause of the very different H pickup rates. In contrast, stress strongly affects H diffusivity. This effect needs to be considered for studying hydride formation and delayed hydride cracking.

  15. Calculations of hydrogen diffusivity in Zr-based alloys: Influence of alloying elements and effect of stress

    Energy Technology Data Exchange (ETDEWEB)

    Yu, J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jiang, C. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Y. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-06-01

    This report summarizes the progress on modeling hydrogen diffusivity in Zr-based alloys. The presence of hydrogen (H) can detrimentally affect the mechanical properties of many metals and alloys. To mitigate these detrimental effects requires fundamental understanding of the thermodynamics and kinetics governing H pickup and hydride formation. In this work, we focus on H diffusion in Zr-based alloys by studying the effects of alloying elements and stress, factors that have been shown to strongly affect H pickup and hydride formation in nuclear fuel claddings. A recently developed accelerated kinetic Monte Carlo method is used for the study. It is found that for the alloys considered here, H diffusivity depends weakly on composition, with negligible effect at high temperatures in the range of 600-1200 K. Therefore, the small variation in compositions of these alloys is likely not a major cause of the very different H pickup rates. In contrast, stress strongly affects H diffusivity. This effect needs to be considered for studying hydride formation and delayed hydride cracking.

  16. Hydrogen effect on the martensite habit planes of titanium alloy quenching

    International Nuclear Information System (INIS)

    Kolachev, B.A.; Fedorova, N.V.; Mamonova, F.S.

    1981-01-01

    The structure of hexagonal α'-martensite in the alloys Ti-2.4% Mo, Ti-4%V and VT6, the structure of rhombic α'' martensite in the alloy Ti-7.5% Mo and hydrogen effect on the martensite structure in the alloys Ti-7.5% Mo and VT6 are studied. It is shown that in the alloy Ti-2.4% Mo martensitic crystals has habit planes (334)sub(β) and (344)sub(β), at that, the (334)sub(β) habit dominates. The increase of molybdenum content up to 7.5% results in the growth of the crystal part with the (344)sub(β) habit. The introduction of 0.05% H into the alloy Ti-7.5% Mo increases the crystal part with the (334)sub(β) habit plane. The habit plane of martensitic crystals in the alloy Ti-4% V is (334)sub(β). The introduction of 6% Al into the alloy results in the appearance in the structure of the alloy Ti-6Al-4 V of the crystals with the (344)sub(β) habit. Hydrogen in the amount of 0.05% does not change the ratio between crystals with the (344)sub(β) habit and (334)sub(β) one in the VT6 alloy [ru

  17. Hydrogen storage behavior of ZrCo1-xNix alloys

    International Nuclear Information System (INIS)

    Jat, Ram Avtar; Parida, S.C.; Agarwal, Renu; Kulkarni, S.G.

    2012-01-01

    Intermetallic compound ZrCo is proposed as a candidate material for storage, supply and recovery of hydrogen isotopes in International Thermonuclear Experimental Reactor (ITER) Storage and Delivery System (SDS). However, it has been reported that upon repeated hydriding-dehydriding cycles, ZrCo undergoes disproportionation as per the reaction; 2ZrCo + H 2 ↔ ZrH 2 + ZrCO 2 . This results in reduction in hydrogen storage capacity of ZrCo, which is not a desirable property for SDS. Konishi et al. reported that the disproportionation reaction can be suppressed by decreasing the desorption temperature. It is anticipated that suitable ternary alloying of ZrCo can elevated the hydrogen equilibrium pressure and hence decrease the desorption temperature for supply of 100 kPa of hydrogen. In this study, we have investigated the effect of Ni content on the hydrogenation behavior of ZrCo 1-x Ni x alloys

  18. Diffusion of hydrogen interstitials in Zr based AB2 and mischmetal based AB5 alloys

    International Nuclear Information System (INIS)

    Mani, N; Ravi, N; Ramaprabhu, S

    2005-01-01

    The Zr based AB 2 alloys ZrMnFe 0.5 Ni 0.5 , ZrMnFe 0.5 Co 0.5 and mischmetal (Mm) based AB 5 alloy MmNi 3.5 Al 0.5 Fe 0.5 Co 0.5 have been prepared and characterized by means of powder x-ray diffractograms. The hydrogen absorption kinetics of these alloys have been studied in the temperature and pressure ranges 450-650 0 C and 10-100 mbar respectively with a maximum H to host alloy formula unit ratio of 0.01, using a pressure reduction technique. The diffusion coefficient of the hydrogen interstitials has been determined from hydrogen absorption kinetics experiments. The dependence of the diffusion coefficient on the alloy content has been discussed. For Mm based MmNi 3.5 Al 0.5 Fe 0.5 Co 0.5 alloy, the diffusion coefficient is about an order of magnitude higher than that of the Zr based alloys

  19. Hydrogen content in titanium and a titanium–zirconium alloy after acid etching

    Energy Technology Data Exchange (ETDEWEB)

    Frank, Matthias J.; Walter, Martin S. [Department of Biomaterials, Institute for Clinical Dentistry, University of Oslo, P.O. Box 1109, Blindern, NO-0317 Oslo (Norway); Institute of Medical and Polymer Engineering, Chair of Medical Engineering, Technische Universität München, Boltzmannstrasse 15, 85748 Garching (Germany); Lyngstadaas, S. Petter [Department of Biomaterials, Institute for Clinical Dentistry, University of Oslo, P.O. Box 1109, Blindern, NO-0317 Oslo (Norway); Wintermantel, Erich [Institute of Medical and Polymer Engineering, Chair of Medical Engineering, Technische Universität München, Boltzmannstrasse 15, 85748 Garching (Germany); Haugen, Håvard J., E-mail: h.j.haugen@odont.uio.no [Department of Biomaterials, Institute for Clinical Dentistry, University of Oslo, P.O. Box 1109, Blindern, NO-0317 Oslo (Norway)

    2013-04-01

    Dental implant alloys made from titanium and zirconium are known for their high mechanical strength, fracture toughness and corrosion resistance in comparison with commercially pure titanium. The aim of the study was to investigate possible differences in the surface chemistry and/or surface topography of titanium and titanium–zirconium surfaces after sand blasting and acid etching. The two surfaces were compared by X-ray photoelectron spectroscopy, secondary ion mass spectroscopy, scanning electron microscopy and profilometry. The 1.9 times greater surface hydrogen concentration of titanium zirconium compared to titanium was found to be the major difference between the two materials. Zirconium appeared to enhance hydride formation on titanium alloys when etched in acid. Surface topography revealed significant differences on the micro and nanoscale. Surface roughness was increased significantly (p < 0.01) on the titanium–zirconium alloy. High-resolution images showed nanostructures only present on titanium zirconium. - Highlights: ► TiZr alloy showed increased hydrogen levels over Ti. ► The alloying element Zr appeared to catalyze hydrogen absorption in Ti. ► Surface roughness was significantly increased for the TiZr alloy over Ti. ► TiZr alloy revealed nanostructures not observed for Ti.

  20. Investigation of Laser Peening Effects on Hydrogen Charged Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Zaleski, Tania M. [San Jose State Univ., CA (United States)

    2008-10-30

    Hydrogen-rich environments such as fuel cell reactors can exhibit damage caused by hydrogen permeation in the form of corrosion cracking by lowering tensile strength and decreasing material ductility. Coatings and liners have been investigated, but there were few shot-peening or laser peening studies referenced in the literature with respect to preventing hydrogen embrittlement. The surface compressive residual stress induced by laser peening had shown success in preventing stress corrosion cracking (SCC) for stainless steels in power plants. The question arose if the residual stresses induced by laser peening could delay the effects of hydrogen in a material. This study investigated the effect of laser peening on hydrogen penetration into metal alloys. Three areas were studied: laser peening, hydrogenation, and hydrogen detection. This study demonstrated that laser peening does not reduce the hydrogen permeation into a stainless steel surface nor does it prevent hydrogen embrittlement. The effect of laser peening to reduce hydrogen-assisted fatigue was unclear.

  1. Treatment of hydrogen storage alloy for battery; Denchiyo suiso kyuzo gokin no shori hoho

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, T.; Negi, N.; Kaminaka, Takeshita, Y.

    1997-03-28

    At present, Ni-Cd battery is mainly used for the power source of portable AV devices and back-up power source of computer memory. From an environmental point of view, however, Ni-hydrogen battery in which hydrogen storage alloy is used instead of Cd as for the negative electrode has been developed. The productivity of Ni-hydrogen battery is not so high because it takes a very long time to activate the battery after it is assembled. This invention solves the problem. According to the invention, the hydrogen storage alloy containing Ni is immersed in a non-oxidizing acid aqueous solution containing dissolved oxygen by 1 mg/L or less. If a large amount of dissolved oxygen is contained in the acid solution, metal appearing on the surface of alloy by the acid treatment is directly combined with the dissolved oxygen, resulting in the re-formation of metal oxide. So that the effect of oxide removal by the acid treatment is reduced. Using the treated hydrogen storage alloy in the Ni-hydrogen battery makes it possible to produce the battery which has a high initial activity and a good storage property with less self-discharge. 2 tabs.

  2. Mechanisms of improving the cyclic stability of V-Ti-based hydrogen storage electrode alloys

    International Nuclear Information System (INIS)

    Miao He; Wang Weiguo

    2010-01-01

    Research highlights: → The corrosion resistance of V-based phase is much lower than that of C14 Laves phase of V-Ti-based alloys. → The addition of Cr which mostly distributes in V-based phase can effectively increase the anti-corrosion ability of V-Ti-based alloys. → The addition of Cr which mostly distributes in V-based phase can effectively increase the anti-corrosion ability of V-Ti-based alloys. - Abstract: In this work, the mechanisms of improving the cyclic stability of V-Ti-based hydrogen storage electrode alloys were investigated systemically. Several key factors for example corrosion resistance, pulverization resistance and oxidation resistance were evaluated individually. The V-based solid solution phase has much lower anti-corrosion ability than C14 Laves phase in KOH solution, and the addition of Cr in V-Ti-based alloys can suppress the dissolution of the main hydrogen absorption elements of the V-based phase in the alkaline solution. During the charge/discharge cycling, the alloy particles crack or break into several pieces, which accelerates their corrosion/oxidation and increases the contact resistance of the alloy electrodes. Proper decreasing the Vickers hardness and enhancing the fracture toughness can increase the pulverization resistance of the alloy particles. The oxidation layer thickness on the alloy particle surface obviously increases during charge/discharge cycling. This deteriorates their electro-catalyst activation to the electrochemical reaction, and leads to a quick degradation. Therefore, enhancing the oxide resistance can obviously improve the cyclic stability of V-Ti-based hydrogen storage electrode alloys.

  3. The influence of surface roughness on the hydrogen permeation of type API 5L-X52 steel; Influencia del acabado superficial en la permeacion de hidrogeno del acero API 5L-X52 steel

    Energy Technology Data Exchange (ETDEWEB)

    Requiz, R; Vera, N; Camero, S

    2004-07-01

    The influence of surface reoughness on the corrosion and hydrogen permeation behaviour was evaluated on a type API 5L-52 steel in dearated 0.1M NaSO{sub 4} at pH=2. Potentiodynamic polarization curves were emplyed to determine the electrochemical behaviour of the steel, while the Devanathan-Stachurski technique was used to estimate the hydrogen permeation rate. Additionally, the surface roughness profiles were obtained in order to correlate the changes in the hydrogen perkeation rate with different metal surface finishings. The obtained results clearly demonstrate that when the roughness parameters have larger values, the cathodic current of hydrogen evolution increases while the hydrogen entry rate decreases. This effect can be attributed to the microstructural defects induced at the steel surface, such as dislocations, which increase the catalytic activity of the atomic hydrogen favouring its recombination. Also, these defects could allow the atomic hydrogen to remain adsorbed on the steel surface. Both effects could hinder the hydrogen diffusion into the metal since the possibility for this atom of becoming absorbed has been reduced. (Author) 16 refs.

  4. Hydrogen absorption in CexGd1−x alloys

    International Nuclear Information System (INIS)

    Bereznitsky, M.; Bloch, J.; Yonovich, M.; Schweke, D.; Mintz, M.H.; Jacob, I.

    2012-01-01

    Highlights: ► Ce x Gd 1−x alloys exhibit the most negative heats of hydride formation ever found. ► Thermodynamics of H absorption in Ce x Gd 1−x correlates with the alloys hardness. ► The entropies of H solution and hydride formation reflect the hydrogen vibrations. ► Terminal hydrogen solubilities change in a monotonic way between Ce and Gd. - Abstract: The effect of alloying on the thermodynamics of hydrogen absorption was studied for Ce x Gd 1−x alloys (0 ≤ x ≤ 1) at temperatures between 850 K and 1050 K in the 1–10 −4 Torr pressure range. The temperature-dependent hydrogen solubilities and plateau pressures for hydride formation were obtained from hydrogen absorption isotherms. The terminal hydrogen solubility (THS) at a given temperature changes in a monotonic way as a function of x. It is approximately three times higher in Gd, than in Ce, throughout the investigated temperature range. This monotonic behavior is opposed to that of many other substitutional alloys, for which the hydrogen terminal solubility increases with increasing solute concentrations. The enthalpies, ΔH f , and the entropies, ΔS f , of the dihydride formation exhibit a pronounced and broad negative minimum starting at x ≈ 0.15, yielding the most negative ΔH f values ever found for metal hydrides. On the other hand, the enthalpies and entropies of ideal solution display a positive trend at x = 0.15 and x = 0.3. Both behaviors are considered in view of a reported distinct variation of the Ce x Gd 1−x hardness as a function of x. The particular compositional variations of the entropies of solution and formation as a function of x reflect most likely the vibrational properties of the hydrogen atoms in the metal matrices.

  5. Hydrogen embrittlement and hydrogen induced stress corrosion cracking of high alloyed austenitic materials; Wasserstoffversproedung und wasserstoffinduzierte Spannungsrisskorrosion hochlegierter austenitischer Werkstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Mummert, K; Uhlemann, M; Engelmann, H J [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany)

    1998-11-01

    The susceptiblity of high alloyed austenitic steels and nickel base alloys to hydrogen-induced cracking is particularly determined by 1. the distribution of hydrogen in the material, and 2. the microstructural deformation behaviour, which last process is determined by the effects of hydrogen with respect to the formation of dislocations and the stacking fault energy. The hydrogen has an influence on the process of slip localization in slip bands, which in turn affects the microstructural deformation behaviour. Slip localization increases with growing Ni contents of the alloys and clearly reduces the ductility of the Ni-base alloy. Although there is a local hydrogen source involved in stress corrosion cracking, emanating from the corrosion process at the cathode, crack growth is observed only in those cases when the hydrogen concentration in a small zone ahead of the crack tip reaches a critical value with respect to the stress conditions. Probability of onset of this process gets lower with growing Ni content of the alloy, due to increasing diffusion velocity of the hydrogen in the austenitic lattice. This is why particularly austenitic steels with low Ni contents are susceptible to transcrystalline stress corrosion cracking. In this case, the microstructural deformation process at the crack tip is also influenced by analogous processes, as could be observed in hydrogen-loaded specimens. (orig./CB) [Deutsch] Die Empfindlichkeit von hochlegierten austentischen Staehlen und Nickelbasislegierungen gegen wasserstoffinduziertes Risswachstum wird im wesentlichen bestimmt durch 1. die Verteilung von Wasserstoff im Werkstoff und 2. das mikrostrukturelle Verformungsverhalten. Das mikrostrukturelle Deformationsverhalten ist wiederum durch den Einfluss von Wasserstoff auf die Versetzungsbildung und die Stapelfehlerenergie charakterisiert. Das mikrostrukturelle Verformungsverhalten wird durch wasserstoffbeeinflusste Gleitlokalisierung in Gleitbaendern bestimmt. Diese nimmt mit

  6. Rapid Solidification of AB{sub 5} Hydrogen Storage Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gulbrandsen-Dahl, Sverre

    2002-01-01

    This doctoral thesis is concerned with rapid solidification of AB{sub 5} materials suitable for electrochemical hydrogen storage. The primary objective of the work has been to characterise the microstructure and crystal structure of the produced AB{sub 5} materials as a function of the process parameters, e.g. the cooling rate during rapid solidification, the determination of which has been paid special attention to. The thesis is divided into 6 parts, of which Part I is a literature review, starting with a short presentation of energy storage alternatives. Then a general review of metal hydrides and their utilisation as energy carriers is presented. This part also includes more detailed descriptions of the crystal structure, the chemical composition and the hydrogen storage properties of AB{sub 5} materials. Furthermore, a description of the chill-block melt spinning process and the gas atomisation process is given. In Part II of the thesis a digital photo calorimetric technique has been developed and applied for obtaining in situ temperature measurements during chill-block melt spinning of a Mm(NiCoMnA1){sub 5} hydride forming alloy (Mm = Mischmetal of rare earths). Compared with conventional colour transmission temperature measurements, this technique offers a special advantage in terms of a high temperature resolutional and positional accuracy, which under the prevailing experimental conditions were found to be {+-}29 K and {+-} 0.1 mm, respectively. Moreover, it is shown that the cooling rate in solid state is approximately 2.5 times higher than that observed during solidification, indicating that the solid ribbon stayed in intimate contact with the wheel surface down to very low metal temperatures before the bond was broken. During this contact period the cooling regime shifted from near ideal in the melt puddle to near Newtonian towards the end, when the heat transfer from the solid ribbon to the wheel became the rate controlling step. In Part III of the

  7. The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Components Delayed Hydride Cracking

    CERN Document Server

    Puls, Manfred P

    2012-01-01

    By drawing together the current theoretical and experimental understanding of the phenomena of delayed hydride cracking (DHC) in zirconium alloys, The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Components: Delayed Hydride Cracking provides a detailed explanation focusing on the properties of hydrogen and hydrides in these alloys. Whilst the focus lies on zirconium alloys, the combination of both the empirical and mechanistic approaches creates a solid understanding that can also be applied to other hydride forming metals.   This up-to-date reference focuses on documented research surrounding DHC, including current methodologies for design and assessment of the results of periodic in-service inspections of pressure tubes in nuclear reactors. Emphasis is placed on showing that our understanding of DHC is supported by progress across a broad range of fields. These include hysteresis associated with first-order phase transformations; phase relationships in coherent crystalline metallic...

  8. Corrosion resistance and cytocompatibility of biodegradable surgical magnesium alloy coated with hydrogenated amorphous silicon.

    Science.gov (United States)

    Xin, Yunchang; Jiang, Jiang; Huo, Kaifu; Tang, Guoyi; Tian, Xiubo; Chu, Paul K

    2009-06-01

    The fast degradation rates in the physiological environment constitute the main limitation for the applications of surgical magnesium alloys as biodegradable hard-tissue implants. In this work, a stable and dense hydrogenated amorphous silicon coating (a-Si:H) with desirable bioactivity is deposited on AZ91 magnesium alloy using magnetron sputtering deposition. Raman spectroscopy and Fourier transform infrared spectroscopy reveal that the coating is mainly composed of hydrogenated amorphous silicon. The hardness of the coated alloy is enhanced significantly and the coating is quite hydrophilic as well. Potentiodynamic polarization results show that the corrosion resistance of the coated alloy is enhanced dramatically. In addition, the deterioration process of the coating in simulated body fluids is systematically investigated by open circuit potential evolution and electrochemical impedance spectroscopy. The cytocompatibility of the coated Mg is evaluated for the first time using hFOB1.19 cells and favorable biocompatibility is observed. 2008 Wiley Periodicals, Inc.

  9. Hydrogen release from irradiated vanadium alloy V-4Cr-4Ti

    Energy Technology Data Exchange (ETDEWEB)

    Klepikov, A.Kh. E-mail: klepikov@ietp.alma-ata.su; Romanenko, O.G.; Chikhray, Y.V.; Tazhibaeva, I.L.; Shestakov, V.P.; Longhurst, G.R. E-mail: gxl@inel.gov

    2000-11-01

    The present work is an attempt to obtain data concerning the influence of neutron and {gamma} irradiation upon hydrogen retention in V-4Cr-4Ti vanadium alloy. The experiments on in-pile loading of vanadium alloy specimens at the neutron flux density 10{sup 14} n/cm{sup 2} s, hydrogen pressure of 80 Pa, and temperatures of 563, 613 and 773 K were carried out using the IVG.1M reactor of the Kazakhstan National Nuclear Center. A preliminary set of loading/degassing experiments with non-irradiated material has been carried out to obtain data on hydrogen interaction with vanadium alloy. The, data presented in this work are related both to non-irradiated and irradiated samples.

  10. Hydrogen release from irradiated vanadium alloy V-4Cr-4Ti

    International Nuclear Information System (INIS)

    Klepikov, A.Kh.; Romanenko, O.G.; Chikhray, Y.V.; Tazhibaeva, I.L.; Shestakov, V.P.; Longhurst, G.R.

    2000-01-01

    The present work is an attempt to obtain data concerning the influence of neutron and γ irradiation upon hydrogen retention in V-4Cr-4Ti vanadium alloy. The experiments on in-pile loading of vanadium alloy specimens at the neutron flux density 10 14 n/cm 2 s, hydrogen pressure of 80 Pa, and temperatures of 563, 613 and 773 K were carried out using the IVG.1M reactor of the Kazakhstan National Nuclear Center. A preliminary set of loading/degassing experiments with non-irradiated material has been carried out to obtain data on hydrogen interaction with vanadium alloy. The, data presented in this work are related both to non-irradiated and irradiated samples

  11. Hydrogen absorption/desorption properties in the TiCrV based alloys

    Directory of Open Access Journals (Sweden)

    A. Martínez

    2012-10-01

    Full Text Available Three different Ti-based alloys with bcc structure and Laves phase were studied. The TiCr1.1V0.9, TiCr1.1V0.45Nb0.45 and TiCr1.1V0.9 + 4%Zr7Ni10 alloys were melted in arc furnace under argon atmosphere. The hydrogen absorption capacity was measured by using aparatus type Sievert's. Crystal structures, and the lattice parameters were determined by using X-ray diffraction, XRD. Microestructural analysis was performed by scanning electron microscope, SEM and electron dispersive X-ray, EDS. The hydrogen storage capacity attained a value of 3.6 wt. (% for TiCr1.1V0.9 alloy in a time of 9 minutes, 3.3 wt. (% for TiCr1.1V0.45Nb0.45 alloy in a time of 7 minutes and 3.6 wt. (% TiCr1.1V0.9 + 4%Zr7Ni10 with an increase of the hydrogen absorption kinetics attained in 2 minutes. This indicates that the addition of Nb and 4%Zr7Ni10 to the TiCrV alloy acts as catalysts to accelerate the hydrogen absorption kinetics.

  12. Hydrogen-absorbing alloys for the nickel-metal hydride battery

    Energy Technology Data Exchange (ETDEWEB)

    Mingming Geng; Jianwen Han; Feng Feng [University of Windsor, Ontario (Canada). Mechanical and Materials Engineering; Northwood, D.O. [University of Windsor, Ontario (Canada). Mechanical and Materials Engineering]|[Ryerson Polytechnic University, Toronto (Canada)

    1998-12-31

    In recent years, owing to the rapid development of portable electronic and electrical appliances, the market for rechargeable batteries has increased at a high rate. The nickel-metal hydride battery (Ni/MH) is one of the more promising types, because of its high capacity, high-rate charge/discharge capability and non-polluting nature. This type of battery uses a hydrogen storage alloy as its negative electrode. The characteristics of the Ni/MH battery, including discharge voltage, high-rate discharge capability and charge/discharge cycle lifetime are mainly determined by the construction of the negative electrode and the composition of the hydrogen-absorbing alloy. The negative electrode of the Ni/MH battery described in this paper was made from a mixture of hydrogen-absorbing alloy, nickel powder and polytetrafluoroethylene (PTFE). A multicomponent MmNi{sub 5}-based alloy (Mm{sub 0.95}Ti{sub 0.05}Ni{sub 3.85} Co{sub 0.45}Mn{sub 0.35}Al{sub 0.35}) was used as the hydrogen-absorbing alloy. The discharge characteristics of the negative electrode, including discharge capacity, cycle lifetime, and polarization overpotential, were studied by means of electrochemical experiments and analysis. The decay of the discharge capacity for the Ni/MH battery (AA size, 1 Ah) was about 1% after 100 charge/discharge cycles and 10% after 500 charge/discharge cycles. (author)

  13. Influence of hydrogen on crack growth rate of alloy 690 CW in PWR conditions

    International Nuclear Information System (INIS)

    Garcia Redondo, M.S.; Perosanz, F.J.; Lapena, J.; Gomez-Briceno, D.

    2015-01-01

    The influence of hydrogen concentration is well established for Alloy 600 and other nickel base alloys as Alloy 182/ 82 weld metals and X-750. It is accepted that for these materials maximum crack growth rate peaks close to Ni/NiO phase boundary. The influence of the hydrogen on the CGR of Alloy 690 is not well established. Available results for Alloy 690 are scarce and not conclusive. Results obtained by CIEMAT, in conditions representative of the PWR operating plants, indicated an apparent crack growth rate increase by a 3 factor when the hydrogen concentration increased from 35 to 81 cm -3 of H 2 /kg H 2 O. In order to gain some insight into the influence of the hydrogen, a new test has been performed with 20 cm -3 H 2 /kg H 2 O at 360 Celsius degrees, concentration close to Ni/NiO phase boundary. The material used was extruded control rod drive mechanism (CRDM) tubes with homogeneous microstructure. Rolling and tensile straining was applied to the CRDM material to obtain 20% of cold work in order to simulate the strain condition expected in the Heat Affected Zone (HAZ). (authors)

  14. Hydrogen storage in binary and ternary Mg-based alloys: A comprehensive experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Kalisvaart, W.P.; Harrower, C.T.; Haagsma, J.; Zahiri, B.; Luber, E.J.; Ophus, C.; Mitlin, D. [Chemical and Materials Engineering, University of Alberta and National Research Council Canada, National Institute for Nanotechnology, T6G 2V4, Edmonton, Alberta (Canada); Poirier, E.; Fritzsche, H. [National Research Council Canada, SIMS, Canadian Neutron Beam Centre, Chalk River Laboratories, Chalk River, Ontario, K0J 1J0 (Canada)

    2010-03-15

    This study focused on hydrogen sorption properties of 1.5 {mu}m thick Mg-based films with Al, Fe and Ti as alloying elements. The binary alloys are used to establish as baseline case for the ternary Mg-Al-Ti, Mg-Fe-Ti and Mg-Al-Fe compositions. We show that the ternary alloys in particular display remarkable sorption behavior: at 200 C the films are capable of absorbing 4-6 wt% hydrogen in seconds, and desorbing in minutes. Furthermore, this sorption behavior is stable over cycling for the Mg-Al-Ti and Mg-Fe-Ti alloys. Even after 100 absorption/desorption cycles, no degradation in capacity or kinetics is observed. For Mg-Al-Fe, the properties are clearly worse compared to the other ternary combinations. These differences are explained by considering the properties of all the different phases present during cycling in terms of their hydrogen affinity and catalytic activity. Based on these considerations, some general design principles for Mg-based hydrogen storage alloys are suggested. (author)

  15. Magnesium-based hydrogen alloy anodes for a nickel metal hydrides secondary battery

    Energy Technology Data Exchange (ETDEWEB)

    Cui, N.; Luan, B.; Zhao, H.J.; Liu, H.K.; Dou, S.X. [Univ of Wollongong, Wollongong, NSW (Australia). Centre for Superconducting and Electronic Materials

    1996-12-31

    Extensive work has been carried out in our group to try utilizing magnesium-based hydrogen storage alloys as a low cost and high performance anode materials for Ni-MH battery. It was found that the modified Mg{sub 2}Ni alloy anodes were able to be charged-discharged effectively in a KOH aqueous solution at ambient temperature. The discharge capacity and cycle have been substantially improved in four ways: (1) by partial substitution of La, Ti, V, Zr, Ca for Mg and Fe, Co, Cu, Al, Si, Y, Mn for Ni in Mg{sub 2}Ni; (2) by composite of Mg{sub 2}Ni with another hydrogen storage alloys; (3) by room-temperature surface microencapsulation and, (4) by ultrasound treatment of alloy powders. A discharge capacity of 170 mAh/g has been obtained from the modified Mg{sub 2}Ni-type alloy electrode, and the cycle life has exceeded 350 cycles. The high rate dischargeability was also significantly improved by the modification. It was concluded that magnesium-based hydrogen storage alloys would become promising anode materials for Ni- MH secondary battery with further improvement of discharge capacity and cycling performance

  16. Magnesium-based hydrogen alloy anodes for a nickel metal hydrides secondary battery

    International Nuclear Information System (INIS)

    Cui, N.; Luan, B.; Zhao, H.J.; Liu, H.K.; Dou, S.X.

    1996-01-01

    Extensive work has been carried out in our group to try utilizing magnesium-based hydrogen storage alloys as a low cost and high performance anode materials for Ni-MH battery. It was found that the modified Mg 2 Ni alloy anodes were able to be charged-discharged effectively in a KOH aqueous solution at ambient temperature. The discharge capacity and cycle have been substantially improved in four ways: (1) by partial substitution of La, Ti, V, Zr, Ca for Mg and Fe, Co, Cu, Al, Si, Y, Mn for Ni in Mg 2 Ni; (2) by composite of Mg 2 Ni with another hydrogen storage alloys; (3) by room-temperature surface microencapsulation and, (4) by ultrasound treatment of alloy powders. A discharge capacity of 170 mAh/g has been obtained from the modified Mg 2 Ni-type alloy electrode, and the cycle life has exceeded 350 cycles. The high rate dischargeability was also significantly improved by the modification. It was concluded that magnesium-based hydrogen storage alloys would become promising anode materials for Ni- MH secondary battery with further improvement of discharge capacity and cycling performance

  17. Modelling of fast hydrogen permeability of alloys for membrane gas separation

    Science.gov (United States)

    Zaika, Yu. V.; Rodchenkova, N. I.

    2017-05-01

    The method of measuring the specific hydrogen permeability is used to study various alloys that are promising for gas separation installations. The nonlinear boundary value problem of hydrogen permeability complying with the specific features of the experiment and its modifications taking into account the high transfer rate is presented. Substantial difference from the quasi-equilibrium model (Richardson approximation in the assumption of the equilibrium Sieverts' law near the surface) has been discussed. The model is tested on published experimental data on Ta77Nb23 alloy.

  18. Hydrogen effects in anodic grinding of WC-Co sintered alloy

    International Nuclear Information System (INIS)

    Lunarska, E.; Zaborski, St.

    2001-01-01

    The effects of anodic polarization applied in grinding of sintered WC C o alloy on properties of surface layer, quality of ground surface and efficiency of the treatment were studied. The nonmonotonical change of the surface roughness, the energy consumption and the wear of tool was stated at increasing anodic polarization. The optimum values of above parameters were achieved at application of anodic polarization at which the Co selective dissolution and hydrogen ingress into the ground metal. affecting the internal friction spectra were stated. The assistance of hydrogen induced deterioration and Co selective dissolution in the surface layer in the anodic grinding of WC-Co alloy has been discussed. (author)

  19. Low cycle fatigue life of two nickel-base casting alloys in a hydrogen environment

    International Nuclear Information System (INIS)

    Cooper, R.A.

    1976-01-01

    Results of low cycle fatigue tests on alloy Mar-M-246 and Inconel 713 are presented. Based on the limited data, it was concluded that the Mar-M-246 material had a cyclic life in hydrogen that averaged three times higher than the alloy 713LC material for similar strain ranges. The hydrogen environment reduced life for both materials. The life reduction was more than an order of magnitude for the 713LC material. Porosity content of the cast specimens was as expected and was an important factor governing low cycle fatigue life

  20. Note: Durability analysis of optical fiber hydrogen sensor based on Pd-Y alloy film.

    Science.gov (United States)

    Huang, Peng-cheng; Chen, You-ping; Zhang, Gang; Song, Han; Liu, Yi

    2016-02-01

    The Pd-Y alloy sensing film has an excellent property for hydrogen detection, but just for one month, the sensing film's property decreases seriously. To study the failure of the sensing film, the XPS spectra analysis was used to explore the chemical content of the Pd-Y alloy film, and analysis results demonstrate that the yttrium was oxidized. The paper presented that such an oxidized process was the potential reason of the failure of the sensing film. By understanding the reason of the failure of the sensing film better, we could improve the manufacturing process to enhance the property of hydrogen sensor.

  1. Gaseous carburising of self-passivating Fe–Cr-Ni alloys in acetylene-hydrogen mixtures

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Hummelshøj, Thomas Strabo; Somers, Marcel A. J.

    2011-01-01

    temperatures, carbon stabilised expanded austenite develops, which has high hardness, while retaining the corrosion performance of the untreated alloy; for relatively high temperatures, Cr based carbides develop, and eventually, the material deteriorates by metal dusting corrosion.......Gaseous carburising of self-passivating Fe–Cr–Ni alloys in acetylene–hydrogen was investigated for temperatures up to 823 K. Acetylene–hydrogen gas mixtures allow both the activation of the surface and the subsequent carburising at a high and adjustable carburising potential. For relatively low...

  2. The electrochemical characteristics of Mg2Ni nanocrystalline hydrogen storage alloy

    International Nuclear Information System (INIS)

    Zhang Ling; Zhou Xiaosong; Peng Shuming

    2008-06-01

    The nanocrystalline Mg 2 Ni materials were prepared by mechanical alloying. The cyclic voltametry results indicated that the potential of oxidation peak was shift as the scan rate increased and the absorption property of Mg 2 Ni prepared by mechanical alloying was increased even at ambient temperature. The absorption and desorption of hydrogen in Mg 2 Ni alloy were remarkably accelerated with the rising temperature. Small angel X-ray scattering results indicated that the Mg 2 Ni powder have 1-5 nm and 5-10 nm particle size distribution, which increased the acting sites of hydrogen absorption/desorption reaction and decreased the diffusion path of hydrogen desorption. It was induced to the enhanced performance of Mg 2 Ni nanocrystalline powder. The cycle life investigated results indicated that the activation property of Mg 2 Ni nanocrystal-line hydrogen storage alloy electrode was excellent, the capacitance maintenance ration was 66% after 200 cycles. The coating of epoxy resin on one side of the electrode had no effect on the activation property and the capacitance maintenance ration was better than the uncoating one. But the anode peak current value and the cathodic peak current value were decreased remarkably which indicated that the hydrogen absorption/desorption rate and the charge/discharge degree had decreased. (authors)

  3. Hydrogen storage in metallic hydrides: the hydrides of magnesium-nickel alloys

    International Nuclear Information System (INIS)

    Silva, E.P. da.

    1981-01-01

    The massive and common use of hydrogen as an energy carrier requires an adequate solution to the problem of storing it. High pressure or low temperatures are not entirely satisfactory, having each a limited range of applications. Reversible metal hydrides cover a range of applications intermediate to high pressure gas and low temperature liquid hydrogen, retaining very favorable safety and energy density characteristics, both for mobile and stationary applications. This work demonstrates the technical viability of storing hydrogen in metal hydrides of magnesium-nickel alloys. Also, it shows that technology, a product of science, can be generated within an academic environment, of the goal is clear, the demand outstanding and the means available. We review briefly theoretical models relating to metal hydride properties, specially the thermodynamics properties relevant to this work. We report our experimental results on hydrides of magnesium-nickel alloys of various compositions including data on structure, hydrogen storage capacities, reaction kinetics, pressure-composition isotherms. We selected a promising alloy for mass production, built and tested a modular storage tank based on the hydrides of the alloy, with a capacity for storing 10 Nm sup(3) of hydrogen of 1 atm and 20 sup(0)C. The tank weighs 46,3 Kg and has a volume of 21 l. (author)

  4. A study of hydrogen environment effects on microstructure property behavior of NASA-23 alloy and related alloy systems

    International Nuclear Information System (INIS)

    Diwan, R.M.

    1990-01-01

    The influence of hydrogen on the tensile properties and ductility behavior of NASA-23 alloy were analyzed. NASA-23 and other referenced alloys in cast and hipped conditions were solution treated and aged under selected conditions and characterized using optical metallography, scanning electron microscopy, and electron microprobe analysis techniques. The yield strength of NASA-23 is not affected much by hydrogen under tensile tests carried at 5000 psig conditions; however, the ultimate strength and ductility properties are degraded. This implies that the physical mechanisms operating would be related to the plastic deformation process. The fracture surfaces characteristics of NASA-23 specimens tensile tested in hydrogen, helium, and air were also analyzed. These revealed surface cracks around specimen periphery with the fracture surface showing a combination of intergranular and transgranular modes of fracture. It is seen that the specimens charged in hydrogen seem to favor a more brittle fracture mode in comparison to air and helium charged specimens. The AMCC casting characterization program is to be analyzed for their hydrogen behavior. As a result of this program, the basic microstructural factors and fracture characteristics in some cases were analyzed

  5. A study of hydrogen environment effects on microstructure property behavior of NASA-23 alloy and related alloy systems

    Science.gov (United States)

    Diwan, Ravinder M.

    1990-01-01

    This work is part of the overall advanced main combustion chamber (AMCC) casting characterization program of the Materials and Processes Laboratory of the Marshall Space Flight Center. The influence of hydrogen on the tensile properties and ductility behavior of NASA-23 alloy were analyzed. NASA-23 and other referenced alloys in cast and hipped conditions were solution treated and aged under selected conditions and characterized using optical metallography, scanning electron microscopy, and electron microprobe analysis techniques. The yield strength of NASA-23 is not affected much by hydrogen under tensile tests carried at 5000 psig conditions; however, the ultimate strength and ductility properties are degraded. This implies that the physical mechanisms operating would be related to the plastic deformation process. The fracture surfaces characteristics of NASA-23 specimens tensile tested in hydrogen, helium, and air were also analyzed. These revealed surface cracks around specimen periphery with the fracture surface showing a combination of intergranular and transgranular modes of fracture. It is seen that the specimens charged in hydrogen seem to favor a more brittle fracture mode in comparison to air and helium charged specimens. The AMCC casting characterization program is to be analyzed for their hydrogen behavior. As a result of this program, the basic microstructural factors and fracture characteristics in some cases were analyzed.

  6. Hydrogen extraction from liquid lithium-lead alloy by bubbling with rotational jet nozzle

    International Nuclear Information System (INIS)

    Xie Bo; Yang Tongzai; Guan Rui; Weng Kuiping

    2010-01-01

    The technology of tritium extraction from lithium-lead alloy has been simulated, hydrogen extraction from lithium-lead alloy by bubbling with rotational jet nozzle being used to simulate tritium in the study based on the introduction of fluid dynamics to establish algebraic model. The results show that the higher than lithium-lead melting temperature, the higher cumulative hydrogen extraction efficiency, and gas holdup of bubble column is little affected by the impeller diameter. Gas holdup when using small aperture is slightly higher when using large aperture only at a high helium flow rate, but the smaller the aperture, the greater the bubble surface area, and a marked increase in intensity of flow circulation for liquid lithium-lead with the increase of helium flow rate, hydrogen extraction rate increases too. Moreover, influence of the jet rotational velocity on hydrogen extraction is limited. (authors)

  7. Hydrogen extraction from liquid lithium-lead alloy by gas-liquid contact method

    International Nuclear Information System (INIS)

    Xie Bo; Weng Kuiping; Hou Jianping; Yang Guangling; Zeng Jun

    2013-01-01

    Hydrogen extraction experiment from liquid lithium-lead alloy by gas-liquid contact method has been carried out in own liquid lithium-lead bubbler (LLLB). Experimental results show that, He is more suitable than Ar as carrier gas in the filler tower. The higher temperature the tower is, the greater hydrogen content the tower exports. Influence of carrier gas flow rate on the hydrogen content in the export is jagged, no obvious rule. Although the difference between experimental results and literature data, but it is feasible that hydrogen isotopes extraction experiment from liquid lithium-lead by gas-liquid contact method, and the higher extraction efficiency increases with the growth of the residence time of the alloy in tower. (authors)

  8. Status and task of the study on the hydrogen embrittlement of zirconium alloys

    International Nuclear Information System (INIS)

    Nagase, Fumihisa; Furuta, Teruo; Seino, Shun; Komatsu, Kazushi.

    1995-08-01

    As the burnup of the LWR fuel is extended, waterside corrosion and hydrogen pickup increase in the Zircaloy cladding. Hydrogen embrittlement of Zircaloy is one of the main factors which may limit the life of the fuel rod. This report presents a review on the hydrogen embrittlement of zirconium and its alloys including the irradiated materials. Research tasks for the reduction of ductility in the high burnup fuel cladding are also discussed. Many fundamental investigations have been performed on the hydrogen embrittlement of zirconium alloys. However, the embrittlement mechanism of the high burnup fuel cladding is complicated. Especially, a coupled effect of hydrides and radiation defects are expected to be pronounced with neutron dose increase. In order to evaluate the reduction of ductility of the higher burnup fuel cladding properly, it is necessary to investigate the coupled effect of these two factors by systematic examinations. (author) 64 refs

  9. AN EVALUATION OF HYDROGEN INDUCED CRACKING SUSCEPTIBILITY OF TITANIUM ALLOYS IN US HIGH-LEVEL NUCLEAR WASTE REPOSITORY ENVIRONMENTS

    Energy Technology Data Exchange (ETDEWEB)

    G. De; K. Mon; G. Gordon; D. Shoesmith; F. Hua

    2006-02-21

    This paper evaluates hydrogen-induced cracking (HIC) susceptibility of titanium alloys in environments anticipated in the Yucca Mountain nuclear waste repository with particular emphasis on the. effect of the oxide passive film on the hydrogen absorption process of titanium alloys being evaluated. The titanium alloys considered in this review include Ti 2, 5 , 7, 9, 11, 12, 16, 17, 18, 24 and 29. In general, the concentration of hydrogen in a titanium alloy can increase due to absorption of atomic hydrogen produced from passive general corrosion of that alloy or galvanic coupling of it to a less noble metal. It is concluded that under the exposure conditions anticipated in the Yucca Mountain repository, the HIC of titanium drip shield will not occur because there will not be sufficient hydrogen in the metal even after 10,000 years of emplacement. Due to the conservatisms adopted in the current evaluation, this assessment is considered very conservative.

  10. AN EVALUATION OF HYDROGEN INDUCED CRACKING SUSCEPTIBILITY OF TITANIUM ALLOYS IN US HIGH-LEVEL NUCLEAR WASTE REPOSITORY ENVIRONMENTS

    International Nuclear Information System (INIS)

    G. De; K. Mon; G. Gordon; D. Shoesmith; F. Hua

    2006-01-01

    This paper evaluates hydrogen-induced cracking (HIC) susceptibility of titanium alloys in environments anticipated in the Yucca Mountain nuclear waste repository with particular emphasis on the. effect of the oxide passive film on the hydrogen absorption process of titanium alloys being evaluated. The titanium alloys considered in this review include Ti 2, 5 , 7, 9, 11, 12, 16, 17, 18, 24 and 29. In general, the concentration of hydrogen in a titanium alloy can increase due to absorption of atomic hydrogen produced from passive general corrosion of that alloy or galvanic coupling of it to a less noble metal. It is concluded that under the exposure conditions anticipated in the Yucca Mountain repository, the HIC of titanium drip shield will not occur because there will not be sufficient hydrogen in the metal even after 10,000 years of emplacement. Due to the conservatisms adopted in the current evaluation, this assessment is considered very conservative

  11. Nickel-hydrogen battery and hydrogen storage alloy electrode; Nikkeru suiso denchi oyobi suiso kyuzo gokin denkyoku

    Energy Technology Data Exchange (ETDEWEB)

    Ono, T. [Furukawa Electric Co. Ltd., Tokyo (Japan); Furukawa, J. [The Furukawa Battery Co. Ltd., Yokohama (Japan)

    1996-03-22

    Hermetically sealed nickel-hydrogen battery has such problem that the inner pressure of the battery elevates when it is overcharged since the oxygen gas evolves from the positive electrode. This invention relates to the hermetically sealed nickel-hydrogen battery consisting of positive electrode composed mainly of nickel hydroxide and negative electrode composed mainly of hydrogen storage alloy. According to the invention, the negative electrode contains organic sulfur compound having carbon-sulfur bond. As a result, the elevation of battery inner pressure due to the hydrogen gas evolution, the decrease in discharge capacity due to the repetition of charge and discharge, and the lowering of voltage after charging can be suppressed. The adequate content of the organic sulfur compound is 0.05 - 1 part in weight to 100 part in weight of hydrogen storage alloy. As for the organic sulfur compound, n-butylthiol, ethylthioethane, phenyldithiobenzene, trimethylsulfonium bromide, thiobenzophenone, 2,4-dinitrobenzenesulfenyl chloride, and ethylene sulphidic acid are employed. 2 figs., 1 tab.

  12. Metallurgically prepared NiCu alloys as cathode materials for hydrogen evolution reaction

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Kunchan; Xia, Ming [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Xiao, Tao [2nd Xiangya Hospital, Central South University, Changsha 410011 (China); Lei, Ting, E-mail: tlei@mail.csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Yan, Weishan [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China)

    2017-01-15

    Ni−Cu bimetallic alloys with Cu content of 5, 10, 20, 30 and 50 wt% are prepared by powder metallurgy method, which consisted of powder mixing, pressing and sintering processes. The X-ray diffraction (XRD) measurement confirms that all the five Ni−Cu alloys possess the f.c.c. structure. The hydrogen evolution reaction (HER) activity of the prepared Ni−Cu alloy electrodes was studied in 6 M KOH solution by cathodic current-potential curves and electrochemical impedance spectroscopy (EIS) techniques. It was found that the electrocatalytic activity for the HER depended on the composition of Ni−Cu alloys, where Ni−10Cu alloy exhibited considerably higher HER activity than Ni plate and other Ni−Cu alloys, indicative of its chemical composition related intrinsic activity. - Highlights: • Ni−Cu alloys with various Cu contents were prepared by powder metallurgy method. • Ni−Cu alloy exhibits chemical composition related synergistic effect for HER activity. • Ni−10Cu alloy electrode presents a most efficient activity for HER. • Two time constants are observed in Nyquist curve and both of them related to the kinetics of HER.

  13. Metallurgically prepared NiCu alloys as cathode materials for hydrogen evolution reaction

    International Nuclear Information System (INIS)

    Wang, Kunchan; Xia, Ming; Xiao, Tao; Lei, Ting; Yan, Weishan

    2017-01-01

    Ni−Cu bimetallic alloys with Cu content of 5, 10, 20, 30 and 50 wt% are prepared by powder metallurgy method, which consisted of powder mixing, pressing and sintering processes. The X-ray diffraction (XRD) measurement confirms that all the five Ni−Cu alloys possess the f.c.c. structure. The hydrogen evolution reaction (HER) activity of the prepared Ni−Cu alloy electrodes was studied in 6 M KOH solution by cathodic current-potential curves and electrochemical impedance spectroscopy (EIS) techniques. It was found that the electrocatalytic activity for the HER depended on the composition of Ni−Cu alloys, where Ni−10Cu alloy exhibited considerably higher HER activity than Ni plate and other Ni−Cu alloys, indicative of its chemical composition related intrinsic activity. - Highlights: • Ni−Cu alloys with various Cu contents were prepared by powder metallurgy method. • Ni−Cu alloy exhibits chemical composition related synergistic effect for HER activity. • Ni−10Cu alloy electrode presents a most efficient activity for HER. • Two time constants are observed in Nyquist curve and both of them related to the kinetics of HER.

  14. Experimental study on the resistance to hydrogen embrittlement of NIFS-V4Cr4Ti alloy

    International Nuclear Information System (INIS)

    Chen Jiming; Xu Zengyu; Den Ying; Muroga, T.

    2002-01-01

    SWIP (Southwestern Institute of Physics) has joined an international collaboration on the hydrogen embrittlement resistance evaluation of the vanadium alloy. This paper presents some experiments on the tensile properties and Charpy impact properties of the NIFS-V4Cr4Ti alloy with high-level hydrogen concentration. The experiment results show different properties against hydrogen embrittlement in static tension and impact load. The critical hydrogen concentration required to embrittle the alloy was about 215 - 310 mg·kg -1 on static tension load, but less than 130 mg·kg -1 on impact loading

  15. Rupture mechanics of metallic alloys for hydrogen transport

    International Nuclear Information System (INIS)

    Moro, I.; Briottet, L.; Lemoine, P.; Andrieu, E.; Blanc, C.

    2007-01-01

    With the aim to establish a cheap hydrogen distribution system, the transport by pipelines is a solution particularly interesting. Among the high limit of elasticity steels, the X80 has been chosen for hydrogen transport. Its chemical composition and microstructure are given. Important microstructural changes have been revealed in the sheet thickness: the microstructure is thinner and richer in perlite in surface than in bulk. In parallel to this microstructural evolution, a microhardness gradient has been observed: the material microhardness is stronger in surface than in bulk of the sheet. The use of this material for hydrogen transport requires to study its resistance to hydrogen embrittlement. The main aim of this work is to develop an easy rupture mechanics test allowing to qualify the studied material in a gaseous hydrogen environment, to determine the sensitivity of the studied material to the hydrogen embrittlement and to better understand the mechanisms of the hydrogen embrittlement for ferritic materials. Two experimental tests have been used for: the first one is a traction machine coupled to an autoclave; the second one allows to carry out disk rupture tests. The toughness of the material in a gaseous hydrogen environment has thus been determined. The resistance of the material to hydrogen embrittlement has been characterized and by simulation, it has been possible to identify the areas with a strong concentration in hydrogen. The second aim of this work is to study the influence of the steel microstructure on the hydrogen position in the material and on the resistance of the material to the hydrogen embrittlement. The preferential trapping sites on the material not mechanically loaded have at first been identified, as well as the hydrogen position on the different phases and at the ferrite/cementite interface. The interaction between the mechanical loads, the position and the trapping of the hydrogen have been studied then. At last, has been

  16. Phase transition and hydrogen storage properties of Mg–Ga alloy

    International Nuclear Information System (INIS)

    Wu, Daifeng; Ouyang, Liuzhang; Wu, Cong; Wang, Hui; Liu, Jiangwen; Sun, Lixian; Zhu, Min

    2015-01-01

    Highlights: • A fully reversible transformation in Mg–Ga–H system with reduced dehydrogenation enthalpy is realized. • The mechanism of phase transformation in the de/hydrogenation of Mg–Ga alloy is revealed. • The de/hydrogenation process of Mg 5 Ga 2 compound is expressed as: Mg 5 Ga 2 + H 2 ↔ 2Mg 2 Ga + MgH 2 . - Abstract: Mg-based alloys are viewed as one of the most promising candidates for hydrogen storage; however, high desorption temperature and the sluggish kinetics of MgH 2 hinder their practical application. Alloying and changing the reaction pathway are effective methods to solve these issues. As the solid solubility of Ga in Mg is 5 wt% at 573 K, the preparation of a Mg(Ga) solid solution at relatively high temperatures was designed in this paper. The phase transition and hydrogen storage properties of the MgH 2 and Mg 5 Ga 2 composite (hereafter referred to as Mg–Ga alloy) were investigated by X-ray diffraction (XRD), pressure–composition-isotherm (PCI) measurements, and differential scanning calorimetry (DSC). The reversible hydrogen storage capacity of Mg–Ga alloy is 5.7 wt% H 2 . During the dehydrogenation process of Mg–Ga alloy, Mg 2 Ga reacts with MgH 2 , initially releasing H 2 and forming Mg 5 Ga 2 ; subsequently, MgH 2 decomposes into Mg with further release of H 2 . The phase transition mechanism of the Mg 5 Ga 2 compound during the dehydrogenation process was also investigated by using in situ XRD analysis. In addition, the dehydrogenation enthalpy and entropy changes, and the apparent activation energy were also calculated

  17. Development of a low tritium partial pressure permeation system for mass transport measurement in lead lithium eutectic

    International Nuclear Information System (INIS)

    Pawelko, R.; Shimada, M.; Katayama, K.; Fukada, S.; Terai, T.

    2014-01-01

    A new experimental system designed to investigate tritium mass transfer properties in materials important to fusion technology is operational at the Safety and Tritium Applied Research (STAR) facility located at the Idaho National Laboratory (INL). The tritium permeation measurement system was developed as part of the Japan/US TITAN collaboration to investigate tritium mass transfer properties in liquid lead lithium eutectic (LLE) alloy. The system is similar to a hydrogen/deuterium permeation measurement system developed at Kyushu University and also incorporates lessons learned from previous tritium permeation experiments conducted at the STAR facility. This paper describes the experimental system that is configured specifically to measure tritium mass transfer properties at low tritium partial pressures. We present preliminary tritium permeation results for α-Fe and α-Fe/LLE samples at 600degC and at tritium partial pressures between 1.0E-3 and 2.4 Pain helium. The preliminary results are compared with literature data. (author)

  18. Hydrogen solubility in iron, platinum and their alloys under pressure up to 67 kbars

    International Nuclear Information System (INIS)

    Belash, I.T.; Antonov, V.E.; Ponyatovskij, E.G.

    1979-01-01

    The solubility of hydrogen was studied in iron, nickel and Fe-Pt-H alloy at a high pressure. It was shown that at T=250 deg C and psub(Hsub(2))=67 kbar, the solubility hy of hydrogen in α-iron and platinum is below the sensitivity threshold of the employed method of chemical analysis, deltasub(n) approximately 0.05 (n - atomic ratio hydrogen metal). At this pressure and at a temperature of T=150 deg C, the equilibrium concentration of hydrogen in non-ordered Fe-Pt alloys with a FCC lattice, containing 25 and 32 at. % Pt, attains, respectively, n = (5+-2)x10 -2 and (2+-5)x10 -2 . Ordering of the alloy with 25 at. % Pt produces no substantial change in the solubility of hydrogen. In a hydrogen atmosphere, the dependence of the Curie point Tsub(c)(psub(Hsub(2)) deviates from Tsub(c)(p). In an inert medium, at p=67 kbar, ΔTsub(c)=Tsub(c)(psub(Hsub(2)) - Tsub(c)(p) = 35+-10 deg C

  19. In-situ electrochemical impedance spectroscopy measurements of zirconium alloy oxide conductivity: Relationship to hydrogen pickup

    International Nuclear Information System (INIS)

    Couet, Adrien; Motta, Arthur T.; Ambard, Antoine; Livigni, Didier

    2017-01-01

    Highlights: • In-situ electrochemistry on zirconium alloys in 360 °C pure water show oxide layer resistivity changes during corrosion. • A linear relationship is observed between oxide resistivity and instantaneous hydrogen pickup fraction. • The resistivity of the oxide layer formed on Zircaloy-4 (and thus its hydrogen pickup fraction) is higher than on Zr-2.5Nb. - Abstract: Hydrogen pickup during nuclear fuel cladding corrosion is a critical life-limiting degradation mechanism for nuclear fuel. Following a program dedicated to zirconium alloys, corrosion, it has been hypothesized that oxide electronic resistivity determines hydrogen pickup. In-situ electrochemical impedance spectroscopy experiments were performed on Zircaloy-4 and Zr-2.5Nb alloys in 360 °C water. The oxide resistivity was measured as function of time. The results show that as the oxide resistivity increases so does the hydrogen pickup fraction. The resistivity of the oxide layer formed on Zircaloy-4 is higher than on Zr-2.5Nb, resulting in a higher hydrogen pickup fraction of Zircaloy-4, compared to Zr-2.5Nb.

  20. Study of hydrogen in metal and alloy by nuclear reaction channeling method

    International Nuclear Information System (INIS)

    Yagi, Eiichi

    1998-01-01

    The position of hydrogen in the lattice was determined by the combination method of 1 H( 11 B, α)αα with a channeling effect of 11 B ion in the crystal. When the concentration of hydrogen in V single crystal was VH 0.1 at the room temperature, hydrogen occupied T position in the body-centered cubic lattice. The position was shifted to the displaced-T by the thermal treatment. Hydrogen in V is oversensitive to a stress, so that it located the displaced-T or 4T state under 7 kg/mm 2 of compressive stress. Hydrogen in Nb and Ta located T position, too. But their displaced states were not observed by the thermal treatment. All hydrogen in Nb-3 at % Mo-2 at % H alloy were captured by Mo and they located the positions of 0.62A displaced from T in the direction of Mo. In Nb-3 at % Mo-5 at % H alloy, a part of hydrogen were captured by Mo, but the other located T positions. At 100degC, hydrogen was free from capture of Mo and moved to T position. (S.Y.)

  1. Rapid Diffusion and Nanosegregation of Hydrogen in Magnesium Alloys from Exposure to Water.

    Science.gov (United States)

    Brady, Michael P; Ievlev, Anton V; Fayek, Mostafa; Leonard, Donovan N; Frith, Matthew G; Meyer, Harry M; Ramirez-Cuesta, Anibal J; Daemen, Luke L; Cheng, Yongqiang; Guo, Wei; Poplawsky, Jonathan D; Ovchinnikova, Olga S; Thomson, Jeffrey; Anovitz, Lawrence M; Rother, Gernot; Shin, Dongwon; Song, Guang-Ling; Davis, Bruce

    2017-11-01

    Hydrogen gas is formed when Mg corrodes in water; however, the manner and extent to which the hydrogen may also enter the Mg metal is poorly understood. Such knowledge is critical as stress corrosion cracking (SCC)/embrittlement phenomena limit many otherwise promising structural and functional uses of Mg. Here, we report via D 2 O/D isotopic tracer and H 2 O exposures with characterization by secondary ion mass spectrometry, inelastic neutron scattering vibrational spectrometry, electron microscopy, and atom probe tomography techniques direct evidence that hydrogen rapidly penetrated tens of micrometers into Mg metal after only 4 h of exposure to water at room temperature. Further, technologically important microalloying additions of mechanical properties of Mg significantly increased the extent of hydrogen ingress, whereas Al additions in the 2-3 wt % range did not. Segregation of hydrogen species was observed at regions of high Mg/Zr/Nd nanoprecipitate density and at Mg(Zr) metastable solid solution microstructural features. We also report evidence that this ingressed hydrogen was unexpectedly present in the alloy as nanoconfined, molecular H 2 . These new insights provide a basis for strategies to design Mg alloys to resist SCC in aqueous environments as well as potentially impact functional uses such as hydrogen storage where increased hydrogen uptake is desired.

  2. First Principles Study of Adsorption of Hydrogen on Typical Alloying Elements and Inclusions in Molten 2219 Al Alloy

    Directory of Open Access Journals (Sweden)

    Yu Liu

    2017-07-01

    Full Text Available To better understand the effect of the components of molten 2219 Al alloy on the hydrogen content dissolved in it, the H adsorption on various positions of alloying element clusters of Cu, Mn and Al, as well as the inclusion of Al2O3, MgO and Al4C3, were investigated by means of first principles calculation, and the thermodynamic stability of H adsorbed on each possible site was also studied on the basis of formation energy. Results show that the interaction between Al, MgO, Al4C3 and H atoms is mainly repulsive and energetically unfavorable; a favorable interaction between Cu, Mn, Al2O3 and H atoms was determined, with H being more likely to be adsorbed on the top of the third atomic layer of Cu(111, the second atomic layer of Mn(111, and the O atom in the third atomic layer of Al2O3, compared with other sites. It was found that alloying elements Cu and Mn and including Al2O3 may increase the hydrogen adsorption in the molten 2219 Al alloy with Al2O3 being the most sensitive component in this regard.

  3. Electrochemical investigations of activation and degradation of hydrogen storage alloy electrodes in sealed Ni/MH battery

    Energy Technology Data Exchange (ETDEWEB)

    Chen, W.X.; Xu, Z.D. [Zhejiang University, Hangzhou (China). Dept. of Chemistry; Tu, J.P. [Zhejiang University, Hangzhou (China). Dept. of Materials Science and Engineering

    2002-04-01

    The M1Ni{sub 0.4}Co{sub 0.6}Al{sub 0.4} alloy was treated with hot alkaline solution containing a small amount of KBH{sub 4} and its effect on the activation and degradation behaviors of the hydrogen storage alloy electrodes in sealed Ni/MH batteries was investigated. It was found that the treated alloy electrode exhibited a better activation property than the untreated one in the sealed battery as well as in open cell. For the treated alloy electrode activating, the polarization resistance in the sealed battery was almost equal to that in the open cell. But in the case of the untreated alloy electrode activating, the polarization resistance in the sealed battery was larger than that in the open cell. The reason is that the oxide film on the untreated alloy surface suppressed the combination of the oxygen evolved on the positive electrode with hydrogen on the negative alloy surface. In addition, the decaying of capacity of the untreated alloy electrode was much faster than that of the treated one. The reasons were, that after surface treatment, the Ni-rich and Al-poor layer on the alloy surface not only had a high electrocatalytic activity for hydrogen electrode reaction, but also facilitated the combination of the oxygen with hydrogen and hydrogen adsorption on the alloy surface. (author)

  4. The hydrogen interaction in an FCC FePd alloy with a vacancy

    Energy Technology Data Exchange (ETDEWEB)

    Ardenghi, S [Instituto de AstronomIa y Fisica del Espacio (IAFE), CC 67-Suc 28 (C1428ZAA) Ciudad Autonoma de Buenos Aires (Argentina); Gonzalez, E; Jasen, P; Juan, A [Departamento de Fisica, Universidad Nacional del Sur, Av. Alem 1253 BahIa Blanca (8000) (Argentina)], E-mail: cajuan@uns.edu.ar

    2009-04-15

    The absorption of hydrogen in the ordered face-centered cubic FePd alloy is investigated using a density functional calculation method. Changes in the electronic structure and bonding after introducing an Fe or Pd vacancy are analysed. H locates close to a tetrahedral site and the H-metal bond is achieved at the expense of the interfacial Fe-Pd bond.

  5. Hydrogen diffusion in Mg–H and Mg–Ni–H alloys

    Czech Academy of Sciences Publication Activity Database

    Čermák, Jiří; Král, Lubomír

    2008-01-01

    Roč. 56, č. 12 (2008), s. 2677-2686 ISSN 1359-6454 R&D Projects: GA ČR GA106/07/0010 Institutional research plan: CEZ:AV0Z20410507 Keywords : intermetallic compounds * magnesium alloys * hydrogen-storage materials Subject RIV: BJ - Thermodynamics Impact factor: 3.729, year: 2008

  6. The annealing behavior of hydrogen implanted into Al-Si alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ogura, Masahiko; Yamaji, Norisuke; Imai, Makoto; Itoh, Akio; Imanishi, Nobutsugu [Kyoto Univ. (Japan). Faculty of Engineering

    1997-03-01

    We have studied effects of not only defects but also an added elements on trap-sites of hydrogen in metals. For the purpose, we observed depth profiles and thermal behaviors of hydrogen implanted into Al-1.5at.%Si alloy samples in an implantation-temperature range of liquid nitrogen temperature (LNT) to 373K at different doses. The results were compared with those for pure aluminum samples. It was found that hydrogen is trapped as molecules in grain boundaries of Al/Si. (author)

  7. Tensile properties of V-Cr-Ti alloys after exposure in hydrogen-containing environments

    International Nuclear Information System (INIS)

    Natesan, K.; Soppet, W.K.

    1998-01-01

    A systematic study has been initiated at Argonne National Laboratory to evaluate the performance of several V-Cr-Ti alloys after exposure to environments containing hydrogen at various partial pressures. The goal is to correlate the chemistry of the exposure environment with hydrogen uptake in the samples and its influence on the microstructure and tensile properties of the alloys. At present, the principal effort has focused on the V-4Cr-4Ti alloy of heat identified as BL-71; however other alloys (V-5Cr-5Ti alloy of heats BL-63, and T87, plus V-4Cr-4Ti alloy from General Atomics [GA]) are also being evaluated. Other variables of interest are the effect of initial grain size on the tensile behavior of the alloys. Experiments conducted on specimens of various V-Cr-Ti alloys exposed to pH 2 levels of 0.01 and 3 x 10 -6 torr showed negligible effect of H 2 on either maximum engineering stress or uniform and total elongation. However, uniform and total elongation decreased substantially when the alloys were exposed to 1.0 torr H 2 pressure. Preliminary data from sequential exposures of the materials to low-pO 2 and several low-pH 2 environments did not reveal an adverse effect on the maximum engineering stress or on uniform and total elongation. Further, tests in H 2 environments on specimens annealed at different temperatures showed that grain-size variation by a factor of ∼2 had little or no effect on tensile properties

  8. Reduction of tritium permeation through Inconel 718 and Incoloy 800 HT by means of natural oxides

    Energy Technology Data Exchange (ETDEWEB)

    Aiello, A., E-mail: antonio.aiello@enea.it [ENEA C.R. Brasimone, I-40032 Camugnano (Italy); Utili, M.; Ciampichetti, A. [ENEA C.R. Brasimone, I-40032 Camugnano (Italy)

    2011-10-01

    Chronical releases of tritium from the helium primary coolant into the water secondary coolant is a fundamental safety issue in the design of a fusion reactor steam generator. It is well known that the steam/water circuit of a fusion reactor would be considered not relevant from a radiological point of view, while if a strong permeation of tritium will be present it will be released together with incondensable gases in the condenser. The permeation of hydrogen isotopes through candidate steam generator materials in different conditions was studied in the past. Further experiments demonstrated that nickel alloys of nuclear interest are always covered by a thin and adherent oxide layer able to reduce permeation of orders of magnitude. The major objective of this work is the evaluation of the permeated flux through nickel alloys, when exposed to pure hydrogen and to an oxidant gas stream, to verify the real permeability of these materials in conditions close to those foreseen in the helium side of the steam generator.

  9. Hydrogen absorption mechanisms and hydrogen interactions - defects: implications to stress corrosion of nickel based alloys in pressurized water reactors primary water

    International Nuclear Information System (INIS)

    Jambon, F.

    2012-01-01

    Since the late 1960's, a special form of stress corrosion cracking (SCC) has been identified for Alloy 600 exposed to pressurized water reactors (PWR) primary water: intergranular cracks develop during the alloy exposure, leading, progressively, to the complete ruin of the structure, and to its replacement. The main goal of this study is therefore to evaluate in which proportions the hydrogen absorbed by the alloy during its exposure to the primary medium can be responsible for SCC crack initiation and propagation. This study is aimed at better understanding of the hydrogen absorption mechanism when a metallic surface is exposed to a passivating PWR primary medium. A second objective is to characterize the interactions of the absorbed hydrogen with the structural defects of the alloy (dislocations, vacancies...) and evaluate to what extent these interactions can have an embrittling effect in relation with SCC phenomenon. Alloy 600-like single-crystals were exposed to a simulated PWR medium where the hydrogen atoms of water or of the pressuring hydrogen gas were isotopically substituted with deuterium, used as a tracer. Secondary ion mass spectrometry depth-profiling of deuterium was performed to characterize the deuterium absorption and localization in the passivated alloy. The results show that the hydrogen absorption during the exposure of the alloy to primary water is associated with the water molecules dissociation during the oxide film build-up. In an other series of experiments, structural defects were created in recrystallized samples, and finely characterized by positron annihilation spectroscopy and transmission electron microscopy, before or after the introduction of cathodic hydrogen. These analyses exhibited a strong hydrogen/defects interaction, evidenced by their structural reorganization under hydrogenation (coalescence, migrations). However, thermal desorption spectroscopy analyses indicated that these interactions are transitory, and dependent on

  10. Hydrogen storage alloy electrode and the nickel-hydrogen secondary battery using the electrode; Suiso kyuzo gokin denkyoku to sorewo mochiita nikkeru/suiso niji denchi

    Energy Technology Data Exchange (ETDEWEB)

    Ono, T. [Furukawa Electric Co. Ltd., Tokyo (Japan); Furukawa, J. [The Furukawa Battery Co. Ltd., Yokohama (Japan)

    1997-02-14

    With respect to the conventional nickel-hydrogen secondary battery, pulverization of the hydrogen storage alloy due to repetition of charging-discharging cycles can be prevented by using a fluorocarbon resin as a binder in manufacture of the hydrogen storage alloy electrode; however, the inner pressure increase of the battery in case of overcharging can not be fully controlled. The invention relates to control of the inner pressure increase of the nickel-hydrogen secondary battery in case of overcharging. As to the hydrogen storage alloy electrode, the compound comprising the hydrogen storage alloy powder as a main ingredient is supported by a current collector; further, the compound particularly comprises a fluororubber as a binder. The nickel-hydrogen secondary battery equipped with the hydrogen storage alloy electrode can control the inner pressure increase of the battery in case of overcharging, and lessen decrease of the battery capacity due to repetition of charging-discharging cycles over long time. The effects are dependent on the use of the fluororubber as a binder which has good flexibility, and strong binding capacity as well as water repellency. 1 tab.

  11. Performance of V-Cr-Ti alloys in a hydrogen environment

    International Nuclear Information System (INIS)

    Natesan, K.; Soppet, W. K.

    2000-01-01

    A systematic study is underway at Argonne National Laboratory to evaluate the mechanical properties of several V-Cr-Ti alloys after exposure to environments containing hydrogen at various partial pressures. The goal is to correlate the chemistry of the exposure environment with hydrogen uptake by the samples and with the resulting influence on microstructures and tensile properties of the alloys. Other variables examined are specimen cooling rate and synergistic effects, if any, of oxygen and hydrogen on tensile behavior of the alloys. Experiments were conducted to evaluate the effect of pH 2 in the range of 3 x 10 -6 and 1 torr on tensile properties of two V-Cr-Ti alloys. Up to pH 2 of 0.05 torr, negligible effect of H was observed on either maximum engineering stress or uniform and total elongation. However, uniform and total elongation decreased substantially when the alloys were exposed at 500 C to 1.0 torr of H 2 pressure. Preliminary data from sequential exposures of the materials to low-pO 2 and several low-pH 2 environments did not reveal adverse effects on the maximum engineering stress or on uniform and total elongation when the alloy contained ∼ 2,000 wppm O and 16 wppm H. Furthermore, tests in H 2 -exposed specimens, initially annealed at various temperatures, showed that grain-size variation by a factor of ∼ 2 had little or no effect on tensile properties. Also, specimen cooling rate had a small effect, if any, on the tensile properties of the alloy

  12. A Study on the VHCF Fatigue Behaviors of Hydrogen Attacked Inconel 718 Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Chang-Min [Kyungpook National Univ., DMI Senior Fellow, Daegu (Korea, Republic of); Nahm, Seung-Hoon [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Kim, Jun-Hyong; Pyun, Young-Sik [Sun Moon Univ., Chunan (Korea, Republic of)

    2016-07-15

    This study is to investigate the influence of hydrogen attack and UNSM on fatigue behaviors of the Inconel 718 alloy. The decrease of the fatigue life between the untreated and the hydrogen attacked material is 10-20%. The fatigue lives of hydrogen attacked specimen decreased without a fatigue limit, similar to those of nonferrous materials. Due to hydrogen embrittlement, about 80% of the surface cracks were smaller than the average grain size of 13 μm. Many small surface cracks caused by the embrittling effect of hydrogen attack were initiated at the grain boundaries and surface scratches. Cracks were irregularly distributed, grew, and then coalesced through tearing, leading to a reduction of fatigue life. Results revealed that the fatigue lives of UNSM-treated specimens were longer than those of the untreated specimens.

  13. Methods for evaluation of hydrogen effect on service behaviour of titanium base alloys

    International Nuclear Information System (INIS)

    Mal'kov, A.V.; Kolachev, B.A.

    1979-01-01

    A comparative evaluation of the effect of hydrogen upon the service ability of α, β, α+β and pseudo-α titanium alloys is carried out using the results of various mechanical tests. Presented are the values of the critical concentration of hydrogen, determined by impact strength tests, tensile tests of notched specimens, fracture toughness tests, slow failure tests and the determination of the energy of failure. A hypothesis is advanced that the failure energy of titanium alloys depends directly upon the type of stressed state. This hypothesis explains the S shapes of the curves describing the dependences of the impact strength, the coefficient of stress intensity and the ratios of the tensile strength of smooth and notched specimens upon the hydrogen content

  14. Application of FEM analytical method for hydrogen migration behaviour in Zirconium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Arioka, K; Ohta, H [Takasago Research and Development Center, Mitsubishi Heavy Industries Ltd, Hyogo-ken (Japan)

    1997-02-01

    It is well recognized that the hydriding behaviours of Zirconium alloys are very significant problems as a safety issues. Also, it is well known that the diffusion of hydrogen in Zirconium alloys are affected not only by concentration but also temperature gradient. But in actual component, especially heat transfer tube such as fuel rod, we can not avoid the temperature gradient in some degree. So, it is very useful to develop the computer code which can analyze the hydrogen diffusion and precipitation behaviours under temperature gradient as a function of the structure of fuel rod. For this objective, we have developed the computer code for hydrogen migration behaviour using FEM analytical methods. So, following items are presented and discussed. Analytical method and conditions; correlation between the computed and test results; application to designing studies. (author). 8 refs, 4 figs, 2 tabs.

  15. The Effect of Toluene Solution on the Hydrogen Absorption of the Mg-Ti Alloy Prepared by Synthetic Alloying

    Directory of Open Access Journals (Sweden)

    H. Suwarno

    2009-07-01

    Full Text Available The synthesis and characterization of the Mg–Ti alloy have been carried out through a mechanical alloying technique under toluene solution. The Mg and Ti powders are milled for 10, 20, and 30 h in a high energy ball mill. The milled alloys are then hydrided at a temperature of 300 oC in order to investigate the possibility used for hydrogen storage materials. The refinement analyses of the x-ray diffraction patterns show that mechanical alloying of the Mg–Ti powders under toluene solution results in the formation of the TiH2 and Mg2Ti phases. Quantitative analyses indicate that the mass fractions of the TiH2 and Mg2Ti phases are 62.90 % and 30.60 %, while the value for Mg and Ti amount to 2.6 wt% and 1.25 wt%. On hydriding at a temperature of 300 oC, the milled powders are transformed into Mg2TiH4, TiH2 and γ-MgH2 phases with the mass fractions of 25.48 wt%, 64.0 wt%, and 10.52 wt%, respectively. Microstructure analyses show that before milling the shape of particle is mostly a ball shape, after 30 h of milling the shape of particles changes into polygonal shape, and upon hydriding the shape of particles changes from a polygonal shape into an irregular one. The final composition of the specimen after hydriding exhibits that Mg-Ti alloy can be promoted as a hydrogen storage material.

  16. Surface treatment for hydrogen storage alloy of nickel/metal hydride battery

    Energy Technology Data Exchange (ETDEWEB)

    Wu, M.-S.; Wu, H.-R.; Wang, Y.-Y.; Wan, C.-C. [National Tsing Hua Univ., Hsinchu (Taiwan). Dept. of Chemical Engineering

    2000-04-28

    The electrochemical performance of AB{sub 2}-type (Ti{sub 0.35}Zr{sub 0.65}Ni{sub 1.2}V{sub 0.6}Mn{sub 0.2}Cr{sub 0.2}) and AB{sub 5}-type (MmB{sub 4.3}(Al{sub 0.3}Mn{sub 0.4}){sub 0.5}) hydrogen storage alloys modified by hot KOH etching and electroless nickel coating has been investigated. It is found that the alloy modified with hot KOH solution shows quick activation but at the expense of cycle-life stability. The alloy coated with nickel was effectively improved in both cycle-life stability and discharge capacity. Both the exchange and limiting current densities were increased by modifying the alloys by hot KOH solution dipping or electroless nickel coating as compared with untreated alloy electrode. The electrode with higher exchange current density and limiting current density leads to increased high-rate dischargeability. A duplex surface modified alloy (i.e., alloy first treated with hot KOH solution and then coated with nickel) has been developed, which performs satisfactorily with respect to both quick activation and long cycle life. In addition, the high-rate dischargeability for the electrode with duplex surface modification is superior to that of electrode solely treated with KOH etching or Ni plating. (orig.)

  17. Modelling of hydrogen assisted cracking of nickel-base Alloy X-750 in water

    International Nuclear Information System (INIS)

    Oka, T.; Ballinger, R.G.; Hwang, I.S.

    1992-01-01

    A closed-form, semi-empirical, electrochemical model has been developed to rationalize the intergranular corrosion fatigue behavior of alloy X-750 in aqueous electrolytes. The model is based on the assumption that, in the electrolytes investigated and for the microstructures studied, that hydrogen assisted crack growth is the dominant mechanism. Further, it is assumed that the rate of hydrogen reduction is a controlling factor in the magnitude of the environmental component of crack growth. Electrolyte conductivity, dissolution and passivation kinetics of precipitates, grain boundary coverage of precipitates are identified as important environmental and microstructural variables governing the hydrogen reduction rate at the crack tip. The model is compared with experimental data for fatigue crack growth where hydrogen is supplied by external charging and with data where galvanically-generated local hydrogen is responsible for enhanced crack growth. It is shown that predicted results characterize the observed effects of frequency, microstructure, electrolyte conductivity, and stress intensity factor. The agreement between the hydrogen reduction model and measured crack growth rate is believed to support the proposed galvanic corrosion mechanism for the intergranular cracking of alloy X-750 in low temperature water

  18. Hydrogen absorption in Ce{sub x}Gd{sub 1-x} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bereznitsky, M. [Department of Nuclear Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel); Bloch, J. [Nuclear Research Center-Negev, P.O. Box 9001, Beer Sheva 84190 (Israel); Yonovich, M. [Department of Nuclear Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel); Schweke, D. [Nuclear Research Center-Negev, P.O. Box 9001, Beer Sheva 84190 (Israel); Mintz, M.H. [Department of Nuclear Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel); Nuclear Research Center-Negev, P.O. Box 9001, Beer Sheva 84190 (Israel); Jacob, I., E-mail: izi@bgu.ac.il [Department of Nuclear Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer Ce{sub x}Gd{sub 1-x} alloys exhibit the most negative heats of hydride formation ever found. Black-Right-Pointing-Pointer Thermodynamics of H absorption in Ce{sub x}Gd{sub 1-x} correlates with the alloys hardness. Black-Right-Pointing-Pointer The entropies of H solution and hydride formation reflect the hydrogen vibrations. Black-Right-Pointing-Pointer Terminal hydrogen solubilities change in a monotonic way between Ce and Gd. - Abstract: The effect of alloying on the thermodynamics of hydrogen absorption was studied for Ce{sub x}Gd{sub 1-x} alloys (0 {<=} x {<=} 1) at temperatures between 850 K and 1050 K in the 1-10{sup -4} Torr pressure range. The temperature-dependent hydrogen solubilities and plateau pressures for hydride formation were obtained from hydrogen absorption isotherms. The terminal hydrogen solubility (THS) at a given temperature changes in a monotonic way as a function of x. It is approximately three times higher in Gd, than in Ce, throughout the investigated temperature range. This monotonic behavior is opposed to that of many other substitutional alloys, for which the hydrogen terminal solubility increases with increasing solute concentrations. The enthalpies, {Delta}H{sub f}, and the entropies, {Delta}S{sub f}, of the dihydride formation exhibit a pronounced and broad negative minimum starting at x Almost-Equal-To 0.15, yielding the most negative {Delta}H{sub f} values ever found for metal hydrides. On the other hand, the enthalpies and entropies of ideal solution display a positive trend at x = 0.15 and x = 0.3. Both behaviors are considered in view of a reported distinct variation of the Ce{sub x}Gd{sub 1-x} hardness as a function of x. The particular compositional variations of the entropies of solution and formation as a function of x reflect most likely the vibrational properties of the hydrogen atoms in the metal matrices.

  19. Study of the high temperature characteristics of hydrogen storage alloys

    CERN Document Server

    Rong, Li; Shaoxiong, Zhou; Yan, Qi; 10.1016/j.jallcom.2004.07.006

    2005-01-01

    In this work, the phase structure of as-cast and melt-spun (MmY)/sub 1/(NiCoMnAl)/sub 5/ alloys (the content of yttrium is 0-2.5wt.%) and their electrochemical properties were studied with regard to discharge capacity at different temperatures (30-80 degrees C) and cycling life at 30 degrees C. It is found that the substitution of yttrium increase the electrochemical capacity of the compounds and decrease the difference in capacity between as-cast and as-quenched compounds at 30 degrees C. When increasing the yttrium concentration from 0 to 2.5wt.%, the cycling life of both the as-cast and the melt- spun compounds deteriorated, although the latter have a slightly longer cycle life than the former. The remarkable feature of the alloys obtained by yttrium substitution is the improvement of the high temperature electrochemical properties. It shows that the stability of the hydrides is increased. Compared with the as-cast alloys, the melt-spun ribbons have higher electrochemical charge /discharge capacity in the ...

  20. Hydrogen in Ti and Zr alloys: industrial perspective, failure modes and mechanistic understanding

    Science.gov (United States)

    Chapman, T. P.; Dye, D.; Rugg, D.

    2017-06-01

    Titanium is widely used in demanding applications, such as in aerospace. Its strength-to-weight ratio and corrosion resistance make it well suited to highly stressed rotating components. Zirconium has a no less critical application where its low neutron capture cross section and good corrosion resistance in hot water and steam make it well suited to reactor core use, including fuel cladding and structures. The similar metallurgical behaviour of these alloy systems makes it alluring to compare and contrast their behaviour. This is rarely undertaken, mostly because the industrial and academic communities studying these alloys have little overlap. The similarities with respect to hydrogen are remarkable, albeit potentially unsurprising, and so this paper aims to provide an overview of the role hydrogen has to play through the material life cycle. This includes the relationship between alloy design and manufacturing process windows, the role of hydrogen in degradation and failure mechanisms and some of the underpinning metallurgy. The potential role of some advanced experimental and modelling techniques will also be explored to give a tentative view of potential for advances in this field in the next decade or so. This article is part of the themed issue 'The challenges of hydrogen and metals'.

  1. Stress corrosion cracking and hydrogen embrittlement of an Al-Zn-Mg-Cu alloy

    International Nuclear Information System (INIS)

    Song, R.G.; Dietzel, W.; Zhang, B.J.; Liu, W.J.; Tseng, M.K.; Atrens, A.

    2004-01-01

    The age hardening, stress corrosion cracking (SCC) and hydrogen embrittlement (HE) of an Al-Zn-Mg-Cu 7175 alloy were investigated experimentally. There were two peak-aged states during ageing. For ageing at 413 K, the strength of the second peak-aged state was slightly higher than that of the first one, whereas the SCC susceptibility was lower, indicating that it is possible to heat treat 7175 to high strength and simultaneously to have high SCC resistance. The SCC susceptibility increased with increasing Mg segregation at the grain boundaries. Hydrogen embrittlement (HE) increased with increased hydrogen charging and decreased with increasing ageing time for the same hydrogen charging conditions. Computer simulations were carried out of (a) the Mg grain boundary segregation using the embedded atom method and (b) the effect of Mg and H segregation on the grain boundary strength using a quasi-chemical approach. The simulations showed that (a) Mg grain boundary segregation in Al-Zn-Mg-Cu alloys is spontaneous, (b) Mg segregation decreases the grain boundary strength, and (c) H embrittles the grain boundary more seriously than does Mg. Therefore, the SCC mechanism of Al-Zn-Mg-Cu alloys is attributed to the combination of HE and Mg segregation induced grain boundary embrittlement

  2. The terminal solid solubility of hydrogen and deuterium in Zr-2.5Nb alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ritchie, I G; Pan, Z L; Puls, M P [Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Labs.

    1997-02-01

    The presence of hydrides in zirconium based alloys is an important factor in assessing the potential for delayed hydride cracking in pressure tubes and the embrittlement of other in-core components fabricated from these alloys. Consequently, the terminal solid solubility (TSS) of hydrogen in the zirconium alloys used in the Nuclear Industry is an important parameter. However, at the low hydrogen concentrations found in practice, the TSS is difficult to measure accurately and even the measurements of hydrogen concentrations by standard techniques are notoriously difficult to make reproducibly at the nominal levels found in pressure tube materials. The presence of hydrides, their dissolution and nucleation gives rise to a number of internal friction phenomena and changes in Young`s modulus that can be useful from the practical point of view. These phenomena can be used to establish expressions for the TSS as a function of temperature, the hysteresis between dissolution and nucleation and hydrogen supercharging from the gas phase. In particular, such studies show that the hysteresis between the TSS measured during heating and cooling is particularly sensitive to the thermal history of the sample. This paper reviews the phenomena involved and presents some recent results on Zr-2.5Nb pressure tube material. (author). 28 refs, 17 figs, 6 tabs.

  3. Absorption of dissolved hydrogen from lithiated water during accelerated corrosion of zirconium-2.5 wt% niobium alloy

    International Nuclear Information System (INIS)

    Manolescu, A.V.; Mayer, P.; Rasile, E.M.; Mummenhoff, J.W.

    1982-01-01

    A series of laboratory experiments was carried out to determine the extent of dissolved hydrogen absorption from lithiated water by zirconium-2.5 wt% niobium alloy during corrosion. The material was exposed at 340 0 C to 1 M LiOH aqueous solution containing 0 to approximately 70 cm 3 /L of dissolved hydrogen. Results indicate that dissolved hydrogen has no effect on the corrosion rate or on the amount of hydrogen absorbed by the material

  4. Modeling and experiments on tritium permeation in fusion reactor blankets

    Science.gov (United States)

    Holland, D. F.; Longhurst, G. R.

    The determination of tritium loss from helium-cooled fusion breeding blankets are discussed. The issues are: (1) applicability of present models to permeation at low tritium pressures; (2) effectiveness of oxide layers in reducing permeation; (3) effectiveness of hydrogen addition as a means to lower tritium permeation; and (4) effectiveness of conversion to tritiated water and subsequent trapping to reduce permeation. Theoretical models applicable to these issues are discussed, and results of experiments in two areas are presented; permeation of mixtures of hydrogen isotopes and conversion to tritiated water.

  5. Modeling and experiments on tritium permeation in fusion reactor blankets

    International Nuclear Information System (INIS)

    Holland, D.F.; Longhurst, G.R.

    1985-01-01

    Issues are discussed that are critical in determining tritium loss from helium-cooled fusion breeding blankets. These issues are: (a) applicability of present models to permeation at low tritium pressures, (b) effectiveness of oxide layers in reducing permeation, (c) effectiveness of hydrogen addition as a means to lower tritium permeation, and (d) effectiveness of conversion to tritiated water and subsequent trapping as a means to reduce permeation. The paper discusses theoretical models applicable to these issues, and presents results of experiments in two areas: permeation of mixtures of hydrogen isotopes and conversion to tritiated water

  6. Hydrogen influence on metals behaviour

    International Nuclear Information System (INIS)

    Tison, P.

    1984-01-01

    Hydrogen isotopes are used in order to investigate the influence of natural oxides and trapping on the permeability of low alloys steels, and martensitic, ferritic, austenitic stainless steels. The permeability of superficial oxides is investigated by reducing and reoxidising the upstream and downstream surfaces (gas ingoing and outgoing faces). The simultaneous or successive use of hydrogen and deuterium enables a direct demonstration of trapping during permeation measurements and a study of the interactions between the diffusing gas and hydrogen absorbed during steel making and processing [fr

  7. Hydrogenated amorphous silicon-selenium alloys - a short journey through parameter space

    International Nuclear Information System (INIS)

    Al-Dallal, S.; Al-Alawi, S.M.; Aljishi, S.

    1999-01-01

    Hydrogenated amorphous silicon-selenium alloy thin films were grown by capacity coupled radio frequency glow discharge decomposition of (SiH/sub 4/ + He) and (H/sub 2/S + He) gas mixtures. In this work we report on a study to correlate the deposition parameters of a-Si, Se:H thin films with its optical, electronic and spectroscopic properties. The alloy composition was varied by changing the gas volume ratio R/sub v/ = [H/sub 2/Se]/[SiH/sub 4/]. The films are characterized via infrared spectroscopy, photoconductivity, photoluminescence, constant current method and conductivity measurements. (author)

  8. The effects of low fugacity hydrogen in duplex- and beta-annealed Ti-6Al-4V alloy

    International Nuclear Information System (INIS)

    Tal-Gutelmacher, E.; Eliezer, D.; Eylon, D.

    2004-01-01

    Due to its excellent combination of a high strength/weight ratio and good corrosion behavior, Ti-6Al-4V alloys are ranked among the most important advanced materials for a variety of aerospace, chemical engineering, biomaterials, marine and commercial applications. However, in many of these technological applications, this alloy is exposed to environments which can act as sources of hydrogen, and severe problems may arise based on its susceptibility to hydrogen embrittlement. Even small hydrogen concentrations might lead to failure. Consequently, a comprehensive knowledge of hydrogen-trapping interactions is necessary to better understand the trapping mechanisms, the types of the trap sites, the trapped hydrogen content, in order to determine the safe service conditions of this alloy in the aerospace industry. The objective of this paper is to investigate the role of microstructure on hydrogen absorption/desorption behavior in Ti-6Al-4V alloy, with specific emphasis on the nature of the interaction between microstructural traps and hydrogen atoms. The effect of low fugacity hydrogen on the microstructure is studied using X-ray diffraction (XRD), and electron microscopy (SEM and TEM), while the absorption and desorption characteristics are determined by means of a hydrogen determinator and thermal desorption spectroscopy (TDS), respectively. The role of microstructure on hydrogen absorption and desorption behavior is discussed in detail

  9. First interactions between hydrogen and stress-induced reverse transformation of Ni-Ti superelastic alloy

    Science.gov (United States)

    Yokoyama, Ken'ichi; Hashimoto, Tatsuki; Sakai, Jun'ichi

    2017-11-01

    The first dynamic interactions between hydrogen and the stress-induced reverse transformation have been investigated by performing an unloading test on a Ni-Ti superelastic alloy subjected to hydrogen charging under a constant applied strain in the elastic deformation region of the martensite phase. Upon unloading the specimen, charged with a small amount of hydrogen, no change in the behaviour of the stress-induced reverse transformation is observed in the stress-strain curve, although the behaviour of the stress-induced martensite transformation changes. With increasing amount of hydrogen charging, the critical stress for the reverse transformation markedly decreases. Eventually, for a larger amount of hydrogen charging, the reverse transformation does not occur, i.e. there is no recovery of the superelastic strain. The residual martensite phase on the side surface of the unloaded specimen is confirmed by X-ray diffraction. Upon training before the unloading test, the properties of the reverse transformation slightly recover after ageing in air at room temperature. The present study indicates that to change the behaviour of the reverse transformation a larger amount of hydrogen than that for the martensite transformation is necessary. In addition, it is likely that a substantial amount of hydrogen in solid solution more strongly suppresses the reverse transformation than hydrogen trapped at defects, thereby stabilising the martensite phase.

  10. Hydrogen migration in fast cooled Pd-H alloys around 50 K

    International Nuclear Information System (INIS)

    Yamakawa, Kohji

    2005-01-01

    The migration of hydrogen in fast cooled Pd-H alloys is investigated by electrical resistivity measurement around 50 K. The disordered atoms of hydrogen are introduced by fast cooling from around 80 K to around 20 K. The disordered atoms are ordered by migration of the atoms during heating-up of the specimens with the constant rates. The resistivity is measured at the temperatures as done by Vajda et al. to compare our results with their results. The activation energy of migration of hydrogen is obtained from the kinetic analysis of the resistivity change due to the ordering using a so-called cross-cut method. The obtained value is compared with our previous results, which have been obtained with hydrogen disordered by quenching into liquid helium, isothermal annealing of the specimen and resistivity measurement in liquid helium. The present value is in fairly good agreement with the value obtained in the quenched case

  11. Preservation of hydrogen absorbing alloy for alkaline storage battery; Arukari chikudenchiyo suiso kyuzo gokin no hozon hoho

    Energy Technology Data Exchange (ETDEWEB)

    Mizutaki, F.

    1996-04-16

    A method of dipping preservation in organic solvent has been practiced conventionally for storing hydrogen absorbing alloy powder. This method is simple and useful in that alloy powder can be isolated simply from the outside environment. Organic solvent, however, generally involves danger of ignition and explosion and is liable to injure the health of workers, and has problems in the handling and workability. This invention relates to preserving hydrogen absorbing alloy by dipping in aqueous solution added with surfactant. The addition of surfactant to alloy preserving aqueous solution is desirable to be from 1 to 10{sup 4}ppm against the total weight of hydrogen absorbing alloy to be dipped. Any type of the anion system, cation system, non-ionic system, and amphoteric system can be used as the surfactant, but anion system surfactant is desirable because it has excellent surface active effect and can form favorable barriers. 2 figs., 1 tab.

  12. Influence of thermo hydrogen treatment on microstructure and mechanical properties of Ti-5Al-2.5Sn ELI alloy

    Directory of Open Access Journals (Sweden)

    Ya-fei Ren

    2017-01-01

    Full Text Available Thermo hydrogen treatment (THT of titanium is a process in which hydrogen is used as a temporary alloying element in titanium alloys. It is an attractive approach for controlling the microstructure and thereby improving the final mechanical properties. In the present study, the microstructure of the original (non-hydrogenated sample has only α phase and the grains is coarse with an average size of ~ 650 μm. While the grain size of thermo hydrogen treated Ti-5Al-2.5Sn ELI alloy became finer and the mechanical properties were improved significantly. When the hydrogen content of the hydrogenated Ti-5Al-2.5Sn ELI alloy is 0.321wt.%, β phase and δ titanium hydride appear. Also the average grain size decreases to 450 μm. When the hydrogen content is 0.515wt.%, the grain size decreases to 220 μm. The mechanical properties were tested after dehydrogenation, and the mechanical properties improved significantly compared to the unhydrogenated specimens. The tensile strength of the Ti-5Al-2.5Sn ELI alloy improved by 17.7% when the hydrogen content increased to 0.920wt.%, at the same time the percentage reduction of area (Z increased by 33% and the impact toughness increased by 37%.

  13. An investigation on the hydrogen storage characteristics of the melt-spun nanocrystalline and amorphous Mg20-xLaxNi10 (x = 0, 2) hydrogen storage alloys

    International Nuclear Information System (INIS)

    Zhang Yanghuan; Li Baowei; Ren Huiping; Guo Shihai; Wu Zhongwang; Wang Xinlin

    2009-01-01

    Mg 2 Ni-type hydrogen storage alloys Mg 20-x La x Ni 10 (x = 0, 2) were prepared by casting and rapid quenching. The structures and morphologies of the as-cast and quenched alloys were studied by X-ray diffraction (XRD), scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM). Thermal stability of the as-quenched alloys was researched by differential scanning calorimetry (DSC). The hydrogen absorption and desorption kinetics of the alloys were measured using an automatically controlled Sieverts apparatus, and their electrochemical properties were measured by a tri-electrode open cell. The results showed that the no amorphous phase formed in the as-quenched La-free alloy, but the as-quenched alloys containing La held a major amorphous phase. The quenching rate induced a light influence on the crystallization temperature of the amorphous phase, and it significantly improved the initial hydrogenation rate and the hydrogen absorption capacity of the alloys. The discharge capacity and the cycle stability of the alloys grew with the increase of the quenching rate. When the quenching rate increased from 0 (as-cast was defined at a quenching rate of 0 m s -1 ) to 30 m s -1 , the hydrogen absorption capacity of the alloys for x = 0 and 2 at 200 deg. C and 1.5 MPa in 10 min changed from 1.21 to 3.10 wt.% and from 1.26 to 2.60 wt.%, the maximum discharge capacity from 30.26 to 135.51 mAh g -1 and from 197.23 to 406.51 mAh g -1 at a current density of 20 mA g -1 , and the capacity retaining rate at 20th cycle from 36.71 to 27.06% and from 37.26 to 78.33%, respectively

  14. Near-surface alloys for hydrogen fuel cell applications

    DEFF Research Database (Denmark)

    Greeley, Jeffrey Philip; Mavrikakis, Manos

    2006-01-01

    of CO with relatively facile H-2 activation is nearly ideal for this application. We suggest that. as nanoscale materials synthesis techniques improve, it will become feasible to reproducibly prepare NSAs with highly specified surface structures, resulting in the design and manufacture of a wide variety...... facile H-2 activation. These NSAs could, potentially, facilitate highly selective hydrogenation reactions at low temperatures. In the present work, the suitability of NSAs for use as hydrogen fuel cell anodes has been evaluated: the combination of properties, possessed by selected NSAs, of weak binding...... of such materials for use in fuel cells and in an ever. increasing range of catalytic applications. Furthermore, we introduce a new concept for NSA-defect sites, which could be responsible for the promotional catalytic effects of a second metal added. even in minute quantities, to a host metal catalyst....

  15. Simulation of hydrogen migration and blisters formation in zirconium alloys

    International Nuclear Information System (INIS)

    Saliba, R.O.

    1991-06-01

    The phenomenon of hydrogen migration and hydride blister growth after pressure tube/calandria tube contact in CANDU reactors is addressed. This phenomenon is by now regarded as an important factor limiting reactors lifetime, since it originated Pickering incident in 1983. Numerical results of thermally-assisted diffusion in excellent agreement with quasi-analytical solutions of the mathematical model were obtained. A sensitivity analysis was performed to assess the accuracy of these results. Some two-dimensional calculations are also included to demonstrate the capabilities of the numerical methods. The main outcomes of the work are the following: a through understanding of the mathematics and physics involved in hydrogen migration under thermal gradients. The validation of a numerical procedure based on a regularization of the constitutive equations. Blister growth rates in slab geometries for initial concentrations that span the full range of technological interest. Some preliminary two-dimensional results allow the design of future developments. (Author) [es

  16. Reforming water to generate hydrogen using mechanical alloy

    International Nuclear Information System (INIS)

    Pena F, D. L.

    2016-01-01

    The objective of this research was to generate a hydrogen production system by means of mechanical milling, in which 0.1 g of magnesium were weighed using a volume of 300 μL for each water solvent (H_2O) and methanol (CH_3OH) in a container to start mechanical milling for 2, 4 and 6 h. Once the mechanical milling was finished, the hydrogen that was produced every two hours was measured to determine the appropriate milling time in the production, also in each period of time samples of the powders produced during the milling of Mg were taken, in this process we used characterization techniques such as: X-ray diffraction at an angle of 2θi 5 and 2θf 90 degrees and scanning electron microscopy, taking micrographs of 100, 500, 1000 and 5000 magnifications. According to the mechanical milling results hydrogen was obtained when using water, as well as with methanol. In the techniques of X-ray diffraction characterization different results were obtained before and after the milling, since by the diffractogram s is possible to observe how the magnesium to be put in the mechanical milling along with the water and methanol was diminishing to be transformed into hydroxide and magnesium oxide, as well as in the micrographs taken with scanning electron microscopy the change in the magnesium morphology to hydroxide and magnesium oxide is observed. (Author)

  17. Some experiments on cold fusion by deuterium hydrogen gas infusion in titanium metal alloy

    International Nuclear Information System (INIS)

    Mestnik Filho, J.; Geraldo, L.P.; Pugliese, R.; Saxena, R.N.; Morato, S.P.; Fulfaro, R.

    1990-05-01

    New results on cold fusion are reported where three different experimental situations have been tried: a) deuterium gas loaded titanium; b) deuterium gas loaded Ti 0.8 Zr 0.2 CrMn alloy and c) titanium and the Ti 0.8 Zr 0.2 CrMn alloy loaded with a mixture of deuterium and hydrogen gases. With these experiments, new thermodynamical non equilibrium conditions were achieved and the possibility of cold fusion between protons and deuterons was also tested. Three independent neutron detectors and one NaI(Tl) were utilized. Despite some large values reported in the literature for the fusion rate, an upper limit of only 8 x 10 -24 fusions/sper deuterium pair or per deuterium-hydrogen pair was determined within the attained accuracy. (author) [pt

  18. Roles of texture in controlling oxidation, hydrogen ingress and hydride formation in Zr alloys

    International Nuclear Information System (INIS)

    Szpunar, Jerzy A.; Qin, Wen; Li, Hualong; Kumar, Kiran

    2011-01-01

    Experimental observations shows that the oxide formed on Zr alloys are strongly textured. The texture and grain-boundary characteristics of oxide are dependent on the texture of metal substrate. Computer simulation and thermodynamic modeling clarify the effect of metal substrate on structure of oxide film, and intrinsic factors affecting the microstructure. Models of diffusion process of hydrogen atoms and oxygen diffusion through oxide are presented. Both intra-granular and inter-granular hydrides were found following (0001) α-Zr //(111) δ-ZrH1.5 relationship. The through-thickness texture inhomogeneity in cladding tubes, the effects of hoop stress on the hydride orientation and the formation of interlinked hydride structure were studied. A thermodynamic model was developed to analyze the nucleation and the stress-induced reorientation of intergranular hydrides. These works provide a framework for understanding the oxidation, the hydrogen ingress and the hydride formation in Zr alloys. (author)

  19. Seawater splitting for high-efficiency hydrogen evolution by alloyed PtNix electrocatalysts

    Science.gov (United States)

    Zheng, Jingjing

    2017-08-01

    Robust electrocatalyst is a prerequisite to realize high-efficiency hydrogen evolution by water splitting. Expensive platinum (Pt) is a preferred electrode catalyst for state-of-the-art hydrogen evolution reaction (HER). We present here a category of alloyed PtNix electrocatalysts by a facile green chemical reduction method, which are used to catalyze HER during seawater splitting. The catalytic performances are optimized by tuning stoichiometric Pt/Ni ratio, yielding a maximized catalytic behavior for PtNi5 electrode. The minimized onset potential is as low as -0.38 V and the corresponding Tafel slope is 119 mV dec-1. Moreover, the launched alloy electrodes have remarkable stability at -1.2 V over 12 h. The high efficiency as well as good durability demonstrates the PtNix electrocatalysts to be promising in practical applications.

  20. Electrocatalytic approach for the efficiency increase of electrolytic hydrogen production: Proof-of-concept using platinum-dysprosium alloys

    International Nuclear Information System (INIS)

    Santos, D.M.F.; Šljukić, B.; Sequeira, C.A.C.; Macciò, D.; Saccone, A.; Figueiredo, J.L.

    2013-01-01

    Development of electrocatalytic materials for the hydrogen evolution reaction (HER) is attempted with the aim of reducing the water electrolysis overpotential and increasing its efficiency. Using linear scan voltammetry measurements of the hydrogen discharge enables evaluation of the electrocatalytic activity for the HER of platinum–dysprosium (Pt–Dy) intermetallic alloy electrodes of different compositions. Understanding of materials electrocatalytic performance is based on determination of several crucial kinetic parameters, including the Tafel coefficients, b, charge transfer coefficients, α, exchange current densities, j 0 , and activation energies, E a . Influence of temperature on HER is investigated by performing studies at temperatures ranging from 25 °C to 85 °C. The effect of the Dy amount in the efficiency of the HER on the Pt–Dy alloys is analysed. Results demonstrate that Dy can substantially increase the electrocatalytic activity of the Pt alloys, in comparison to the single Pt electrode. Efforts are made to correlate the microstructure of the alloys with their performance towards the HER. - Highlights: ► Development of electrocatalysts to increase efficiency of electrolytic hydrogen production. ► Synthesis and evaluation of composition and morphology of platinum–dysprosium (Pt–Dy) alloys. ► Hydrogen evolution reaction on Pt–Dy alloys electrodes studied using linear scan voltammetry in alkaline medium. ► Pt–Dy alloy with equiatomic composition enhances kinetics of hydrogen discharge compared to single Pt

  1. Manufacturing method of hydrogen storage alloy powder for battery; Denchiyo suiso kyuzo gokin funmatsu no seizo hoho

    Energy Technology Data Exchange (ETDEWEB)

    Furukawa, J.

    1997-04-04

    To produce hydrogen storage alloy powder for battery, ingot of a hydrogen storage alloy is crushed to coarse grains of a suitable size with a crusher and then, finely pulverized to a certain particle size with a ball mill or some other tools. In this pulverization process, the surface of the pulverized alloy powder is oxidized and the surface activity is partially lost to cause a problem of a decrease of the characteristics of the produced hydrogen storage alloy electrode. In this invention, ingot of hydrogen storage alloy is crushed to coarse alloy grains in a non-oxidizing atmosphere followed by mechanical pulverization in a state contact with a solution of sulfites, hypophosphites, hydrogen phosphates or dihydrogen phosphates. This treatment method prevents surface oxidation of the alloy powder during the pulverization process. As a result, the initial activity of the battery is improved and an increase of the internal pressure of the battery on overcharge is suppressed. The use of an aqueous alkaline solution containing cobalt instead of the above-mentioned solution gives a similar effect. 2 tabs.

  2. Effect of hydrogen on transformation characteristics and deformation behavior in a Ti-Ni shape memory alloy

    International Nuclear Information System (INIS)

    Hoshiya, Taiji; Ando, Hiroei; Den, Shoji; Katsuta, Hiroshi.

    1992-01-01

    Transformation characteristics and deformation behavior of hydrogenated Ti-50.5 at% Ni alloys, which were occluded in a low pressure range of hydrogen between 1.1 and 78.5 kPa, have been studied by electrical resistivity measurement, tensile test, X-ray diffraction analysis and microstructural observation. M S temperature of the Ti-Ni alloys decreased with an increase in hydrogen content. This corresponds to the stabilization of the parent phase during cooling, which was confirmed by X-ray diffraction: The suppression effect of hydrogen takes place on the martensitic transformation. Critical stress for slip deformation of hydrogenated Ti-Ni alloys changed with hydrogen content and thus hydrogen had a major influence on deformation behavior of those alloys. With hydrogen contents above 0.032 mol%, hardening was distinguished from softening which was pronounced in the contents from 0 to 0.032 mol% H. Hydrides were formed in hydrogen contents over 1.9 mol%. The hydride formation results in the reorientation in variants of the R phase and increase in the lattice strains of the parent phase. (author)

  3. Effect of trace solute hydrogen on the fatigue life of electron beam welded Ti-6Al-4V alloy joints

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Junhui; Hu, Shubing, E-mail: 187352581@qq.com; Ji, Longbo

    2017-01-27

    This paper describes an experimental hydrogenating treatment on a Ti-6Al-4V fatigue specimen containing an electron beam welding joint. The effect of trace solute hydrogen on the microstructures and fatigue behavior of welded Ti-6Al-4V alloy joints was investigated using an optical microscope, X-ray diffractometer, scanning electron microscope, transmission electron microscope and other methodologies. The results demonstrated that no hydride formed in the hydrogenated weld joint at a hydrogen concentration of less than 0.140 wt%. Internal hydrogen, which was present in the alloy in the form of solid solution atoms, caused lattice distortion in the β phase. The fatigue properties of the Ti-6Al-4V weld joint hydrogenated with trace solute hydrogen decreased significantly. The solute hydrogen led to an increase in the brittleness of the hydrogenated weld joint. The dislocation densities in the secondary α and β phase were higher. Fatigue cracks nucleated at the α/β interfaces. The effect of solute hydrogen accelerated the separation of the persistent slip bands, which decreased the threshold required for fatigue crack growth. Solute hydrogen also accelerated the fatigue crack growth rate. These two factors contributed to the degradation of the fatigue life in the electron beam welded Ti-6Al-4V alloy joints.

  4. Nanostructuring of Aluminum Alloy Powders by Cryogenic Attrition with Hydrogen-Free Process Control Agent

    Science.gov (United States)

    2015-02-01

    Nanostructuring of Aluminum Alloy Powders by Cryogenic Attrition with Hydrogen-Free Process Control Agent by Frank Kellogg , Clara Hofmeister...Process Control Agent Frank Kellogg Bowhead Science and Technology Clara Hofmeister Advanced Materials Processing and Analysis Center...NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Frank Kellogg , Clara Hofmeister, Anit Giri, and Kyu Cho 5d. PROJECT NUMBER 5e

  5. Hydrogen effect on tendency to delayed brittle fracture in titanium alloys

    International Nuclear Information System (INIS)

    Nazimov, O.P.; Bunin, L.A.; Il'in, A.A.; Ponomareva, N.A.

    1979-01-01

    The results of investigating hydrogen effetc on the tendency to delayed fracture of the titanium alloys of VT1-0, VT5, VT5-1, OT4, VT6S and VT14 are given. The delayed fracture test data have been compared with the results of fractographic investigations. The notion of structural instability in the initial condition during the tests was suggested as a criterion for evaluating the tendency of metal to delayed fracture

  6. Hydrogen effects in nitrogen-alloyed austenitic steels; Wirkung von Wasserstoff in stickstofflegierten austenitischen Staehlen

    Energy Technology Data Exchange (ETDEWEB)

    Uhlemann, M.; Mummert, K. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany); Shehata, M.F. [National Research Centre, Cairo (Egypt)

    1998-12-31

    Hydrogen increases the yield strength of nitrogen-alloyed steels, but on the other hand adversely affects properties such as tensile strength and elongation to fracture. The effect is enhanced with increasing nitrogen and hydrogen contents. Under the effect of hydrogen addition, the discontinuous stress-strain characteristic and the distinct elongation limit of hydrogen-free, nitrogen containing steels is no longer observed in the material. This change of mechanical properties is attributed to an interatomic interaction of nitrogen and hydrogen in the lattice, which is shown for instance by such effects as reduction of hydrogen velocity, high solubility, and a particularly strong lattice expansion. The nature of this interaction of nitrogen and hydrogen in the fcc lattice remains to be identified. (orig./CB) [Deutsch] Wasserstoff fuehrt in stickstofflegierten Staehlen zu einer Erhoehung der Streckgrenze, aber gleichzeitig zu einer Abnahme der Zugfestigkeit und Bruchdehnung. Dieser Effekt verstaerkt sich mit zunehmenden Stickstoff- und Wasserstoffgehalten. Ein diskontinuierlicher Spannungs-Dehnungsverlauf mit einer ausgepraegten Streckgrenze in wasserstofffreien hochstickstoffhaltigen Staehlen wird nach Wasserstoffeinfluss nicht mehr beobachtet. Die Aenderung der mechanischen Eigenschaften, wird auf eine interatomare Wechselwirkung von Stickstoff und Wasserstoff im Gitter zurueckgefuehrt, die sich u.a. in geringer Wasserstoffdiffusionsgeschwindigkeit, hoher Loeslichkeit und vor allem in extremer Gitteraufweitung aeussert. Insgesamt ist die Natur der Wechselwirkung zwischen Stickstoff und Wasserstoff im kfz Gitter noch nicht aufgeklaert. (orig.)

  7. Mechanical alloying of TiFe intermetallic for hydrogen storage

    International Nuclear Information System (INIS)

    Vega, L.E.R.; Leiva, D.R.; Silva, W.B.; Ishikawa, T.T.; Botta, W.J.; Leal Neto, R.M.

    2016-01-01

    Elementary powders of Ti and Fe in the stoichiometric ratio 50:50 were submitted to mechanical alloying for 2, 6, 10 and 20 h in a planetary ball mill. The synthesis of TiFe intermetallic with high yield was achieved for all milling times. The structural characterization of the samples revealed the trend of the particles to form agglomerates and the formation of cracks. H-absorption capacities of 0,74; 0,90; 0,97 and 0,95 wt. % (at room temperature and 20 bar of H2) were obtained for processing times of 2, 6, 10 and 20 h, respectively, without using a thermal activation process after milling. (author)

  8. Combinatorial search for hydrogen storage alloys: Mg-Ni and Mg-Ni-Ti

    Energy Technology Data Exchange (ETDEWEB)

    Oelmez, Rabia; Cakmak, Guelhan; Oeztuerk, Tayfur [Dept. of Metallurgical and Materials Engineering, Middle East Technical University, 06531 Ankara (Turkey)

    2010-11-15

    A combinatorial study was carried out for hydrogen storage alloys involving processes similar to those normally used in their fabrication. The study utilized a single sample of combined elemental (or compound) powders which were milled and consolidated into a bulk form and subsequently deformed to heavy strains. The mixture was then subjected to a post annealing treatment, which brings about solid state reactions between the powders, yielding equilibrium phases in the respective alloy system. A sample, comprising the equilibrium phases, was then pulverized and screened for hydrogen storage compositions. X-ray diffraction was used as a screening tool, the sample having been examined both in the as processed and the hydrogenated state. The method was successfully applied to Mg-Ni and Mg-Ni-Ti yielding the well known Mg{sub 2}Ni as the storage composition. It is concluded that a partitioning of the alloy system into regions of similar solidus temperature would be required to encompass the full spectrum of equilibrium phases. (author)

  9. Internal friction and Young's modulus measurements in Zr-2.5Nb alloy doped with hydrogen

    International Nuclear Information System (INIS)

    Ritchie, I.G.; Pan, Z.-L.

    1992-01-01

    The presence of hydrides is an important factor in assessing the potential for delayed hydride cracking in Zr-2.5Nb alloys, and consequently, the terminal solid solubility (TSS) of hydrogen in the material is an important parameter. In pure zirconium doped with hydrogen, the TSS is marked by a dissolution peak of internal friction on heating and a truncated precipitation peak associated with hydride nucleation on cooling. These phenomena occur only at low frequencies and are accompanied in torsion pendulum studies by autotwisting of the sample (or zero-point drift) that stops abruptly at the TSS. Neither the dissolution/precipitation peaks nor the autotwisting phenomena are observed in Zr-2.5Nb. However, the TSS is also marked by an abrupt change in the slope of Young's modulus as a function of temperature. This phenomenon is observed regardless of the frequency (in the range 1 Hz to 120 kHz) and in both pure zirconium and Zr-2.5Nb alloys. The reasons for the absence of the dissolution/precipitation peak in Zr-2.5Nb alloys are discussed and the use of Young's modulus changes to investigate the TSS of hydrogen and the hysteresis between heat-up and cool-down TSS curves is demonstrated. (author)

  10. Magnesium-Nickel alloy for hydrogen storage produced by melt spinning followed by cold rolling

    Directory of Open Access Journals (Sweden)

    Daniel Rodrigo Leiva

    2012-10-01

    Full Text Available Severe plastic deformation routes (SPD have been shown to be attractive for short time preparation of magnesium alloys for hydrogen storage, generating refined microstructures and interesting hydrogen storage properties when compared to the same materials processed by high-energy ball milling (HEBM, but with the benefit of higher air resistance. In this study, we present results of a new processing route for Mg alloys for hydrogen storage: rapid solidification followed by cold work. A Mg97Ni3 alloy was processed by melt spinning (MS and by extensive cold rolling (CR. Submitting Mg97Ni3 ribbons between steel plates to cold rolling has shown to be a viable procedure, producing a thin cold welded foil, with little material waste. The as-processed material presents a high level of [002] fiber texture, a sub microcrystalline grain structure with a high density of defects, and also a fine dispersion of Mg2Ni nanoparticles. This refined microstructure allied to the developed texture resulted in enhanced activation and H-sorption kinetics properties.

  11. Synthesis and electrochemical properties of binary MgTi and ternary MgTiX (X=Ni, Si) hydrogen storage alloys

    NARCIS (Netherlands)

    Gobichettipalayam Manivasagam, T.; Iliksu, M.; Danilov, D.L.; Notten, P.H.L.

    2017-01-01

    Mg-based hydrogen storage alloys are promising candidate for many hydrogen storage applications because of the high gravimetric hydrogen storage capacity and favourable (de)hydrogenation kinetics. In the present study we have investigated the synthesis and electrochemical hydrogen storage properties

  12. Electrodeposition and characterization of Fe–Mo alloys as cathodes for hydrogen evolution in the process of chlorate

    Directory of Open Access Journals (Sweden)

    B. N. GRGUR

    2005-06-01

    Full Text Available Fe–Mo alloys were electrodeposited from a pyrophosphate bath using a single diode rectified AC current. Their composition and morphology were investigated by SEM, optical microscopy and EDS, in order to determine the influence of the deposition conditions on the morphology and composition of these alloys. It was shown that the electrodeposition parameters, such as: chemical bath composition and current density, influenced both the composition of the Fe–Mo alloys and the current efficiency for their deposition, while the micro and macro-morphology did not change significantly with changing conditions of alloy electrodeposition. It was found that the electrodeposited Fe–Mo alloys possessed a 0.15 V to 0.30 V lower overvoltage than mild steel for hydrogen evolution in an electrolyte commonly used in commercial chlorate production, depending on the alloy composition, i.e., the conditions of alloy electrodeposition.

  13. Passivation behavior of AB{sub 5}-type hydrogen storage alloys for battery electrode application

    Energy Technology Data Exchange (ETDEWEB)

    Meli, F. [Fribourg Univ. (Switzerland). Inst. de Physique; Sakai, T. [Fribourg Univ. (Switzerland). Inst. de Physique; Zuettel, A. [Fribourg Univ. (Switzerland). Inst. de Physique; Schlapbach, L. [Fribourg Univ. (Switzerland). Inst. de Physique

    1995-04-15

    In many applications, AB{sub 5} type hydrogen storage alloys show passivation behavior, i.e. when fully discharged, metal hydride electrodes show (especially at higher temperatures) a decrease in activity and therefore a decrease in capacity at normal discharge currents for ensuing cycles. Passivation may continue to the point where activity becomes so low that the capacity is no longer accessible. Electrochemical measurements were taken of two different AB{sub 5}-type alloys, one with manganese and one without manganese (LaNi{sub 3.4}Co{sub 1.2}Al{sub 0.4} and LaNi{sub 3.4}Co{sub 1.2}Al{sub 0.3}Mn{sub 0.1}). Both alloys showed passivation behavior after remaining in the discharged state. The alloy with manganese showed a stronger tendency to passivation which is in contradiction with earlier observations. Photoelectron spectroscopic analysis together with sputter depth profiling was used to investigate the surface composition of samples which had undergone different surface pretreatments. Surface analysis of electrodes in the passivated state shows a lower content of metallic nickel and a thicker nickel surface oxide film. We attribute the low electrochemical kinetics of the alloys after passivation to the loss of metallic nickel and/or cobalt at the electrode-electrolyte interface. ((orig.))

  14. The effect of hydrogen peroxide concentration on metal ion release from dental casting alloys.

    Science.gov (United States)

    Al-Salehi, S K; Hatton, P V; Johnson, A; Cox, A G; McLeod, C

    2008-04-01

    There are concerns that tooth bleaching agents may adversely affect dental materials. The aim of this study was to test the hypothesis that increasing concentrations of hydrogen peroxide (HP) are more effective than water at increasing metal ion release from two typical dental casting alloys during bleaching. Discs (n = 28 for each alloy) were prepared by casting and heat treated to simulate a typical porcelain-firing cycle. Discs (n = 7) of each alloy were immersed in either 0%, 3%, 10% or 30% (w/v) HP solutions for 24 h at 37 degrees C. Samples were taken for metal ion release determination using inductively coupled plasma-mass spectrometry and the data analysed using a two-way anova followed by a one-way anova. The surface roughness of each disc was measured using a Talysurf contact profilometer before and after bleaching and the data analysed using a paired t-test. With the exception of gold, the differences in metal ion concentration after treatment with 0% (control) and each of 3%, 10% and 30% HP (w/v) were statistically significant (P alloys increased with increasing HP concentrations (over 3000% increase in Ni and 1400% increase in Pd ions were recorded when HP concentration increased from 0% to 30%). Surface roughness values of the samples before and after bleaching were not significantly different (P > 0.05) Exposure of the two dental casting alloys to HP solutions increased metal ion release of all the elements except gold.

  15. Determination of very low concentrations of hydrogen in zirconium alloys by neutron imaging

    Science.gov (United States)

    Buitrago, N. L.; Santisteban, J. R.; Tartaglione, A.; Marín, J.; Barrow, L.; Daymond, M. R.; Schulz, M.; Grosse, M.; Tremsin, A.; Lehmann, E.; Kaestner, A.; Kelleher, J.; Kabra, S.

    2018-05-01

    Zr-based alloys are used in nuclear power plants because of a unique combination of very low neutron absorption and excellent mechanical properties and corrosion resistance at operating conditions. However, Hydrogen (H) or Deuterium ingress due to waterside corrosion during operation can embrittle these materials. In particular, Zr alloys are affected by Delayed Hydride Cracking (DHC), a stress-corrosion cracking mechanism operating at very low H content (∼100-300 wt ppm), which involves the diffusion of H to the crack tip. H content in Zr alloys is commonly determined by destructive techniques such as inert gas fusion and vacuum extraction. In this work, we have used neutron imaging to non-destructively quantify the spatial distribution of H in Zr alloys specimens with a resolution of ∼5 wt ppm, an accuracy of ∼10 wt ppm and a spatial resolution of ∼25 μm × 5 mm x 10 mm. Non-destructive experiments performed on a comprehensive set of calibrated specimens of Zircaloy-2 and Zr2.5%Nb at four neutron facilities worldwide show the typical precision and repeatability of the technique. We have observed that the microstructure of the alloy plays an important role on the homogeneity of H across a specimen. We propose several strategies for performing H determinations without calibrated specimens, with the most precise results for neutrons having wavelengths longer than 5.7 Å.

  16. Properties of mechanically alloyed Mg-Ni-Ti ternary hydrogen storage alloys for Ni-MH batteries

    Science.gov (United States)

    Ruggeri, Stéphane; Roué, Lionel; Huot, Jacques; Schulz, Robert; Aymard, Luc; Tarascon, Jean-Marie

    MgNiTi x, Mg 1- xTi xNi and MgNi 1- xTi x (with x varying from 0 to 0.5) alloys have been prepared by high energy ball milling and tested as hydrogen storage electrodes. The initial discharge capacities of the Mg-Ni-Ti ternary alloys are inferior to the MgNi electrode capacity. However, an exception is observed with MgNi 0.95Ti 0.05, which has an initial discharge capacity of 575 mAh/g compared to 522 mAh/g for the MgNi electrode. The Mg-Ni-Ti ternary alloys show improved cycle life compared to Mg-Ni binary alloys with the same Mg/Ni atomic ratio. The best cycle life is observed with Mg 0.5Ti 0.5Ni electrode which retains 75% of initial capacity after 10 cycles in comparison to 39% for MgNi electrodes, in addition to improved high-rate dischargeability (HRD). According to the XPS analysis, the cycle life improvement of the Mg 0.5Ti 0.5Ni electrode can be related to the formation of TiO 2 which limits Mg(OH) 2 formation. The anodic polarization curve of Mg 0.5Ti 0.5Ni electrode shows that the current related to the active/passive transition is much less important and that the passive region is more extended than for the MgNi electrode but the corrosion of the electrode is still significant. This suggests that the cycle life improvement would be also associated with a decrease of the particle pulverization upon cycling.

  17. Hydrogen isotope storage behavior of Zr1-xTixCo alloys

    International Nuclear Information System (INIS)

    Jat, Ram Avtar; Pati, Subhasis; Parida, S.C.; Agarwal, Renu; Mukerjee, S.K.

    2016-01-01

    Tritium storage properties similar to uranium make ZrCo as a suitable candidate material for storage, supply and recovery of hydrogen isotopes in various tritium facilities. Beside non-radioactive, nonpyrophoric at room temperature and higher storage capacity (H/f.u. up to 3, f.u. = ZrCo), it has been reported that upon repeated hydriding-dehydriding cycles, ZrCo undergoes dis-proportionation as per the reaction; ZrCo + H 2 ↔ ZrH 2 + ZrCo 2 . The present study is aimed to investigate the effect of Ti content on the hydrogen storage behavior of Zr 1-x Ti x Co alloys and the hydrogen isotope effect

  18. Characterization of SCC crack tip and hydrogen distribution in alloy 600

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Katsuhiko; Nakajima, Nobuo; Fukuya, Koji [Institute of Nuclear Safety System Inc., Mihama, Fukui (Japan); Hatano, Yuji [Toyama Univ. (Japan)

    2001-09-01

    In order to identify the mechanism of primary water stress corrosion cracking (SCC), direct observations of SCC crack tip microstructure and hydrogen distribution in alloy 600 were carried out. A new technique has been developed to prepare electron transparent foils including the crack tip using focused-ion beam (FIB) micro-processing technique. Cr-rich oxide and metal-Ni phase were identified in the crack tip and grain boundary ahead of the crack. >From the fact that similar microstructure was observed in the surface oxide layer, it is suggested that the oxidation mechanism is identical at the crack tip region and the surface. It became clear that the crack tip region and the oxidized grain boundary don't work as strong trapping sites of solute hydrogen under unloaded condition, because a homogeneous hydrogen distribution around the crack tip region was detected by tritium microautoradiography. (author)

  19. Hydrogenation of the rare earth alloys for production negative electrodes of nickel-metal hydride batteries

    International Nuclear Information System (INIS)

    Casini, Julio Cesar Serafim

    2011-01-01

    In this work were studied of La 0.7-x Mg x Pr 0.3 Al 0.3 Mn 0.4 Co 0.5 Ni 3.8 (X = 0 and 0.7) alloys for negative electrodes of the nickel-metal hydride batteries. The hydrogenation of the alloys was performed varying pressing of H 2 (2 and 10 bar) and temperature (room and 500 ℃). The discharge capacity of the nic kel-metal hydride batteries were analyzed in ARBIN BT- 4 electrical test equipment. The as-cast alloys were analyzed by scanning electron microscopy (SEM), energy disperse spectroscopy (EDX) and X-Ray diffraction. The increasing Mg addition in the alloy increases maximum discharge capacity but decrease cycle life of the batteries. The maximum discharge capacity was obtained with the Mg 0.7 Pr 0.3 Al 0.3 Mn 0.4 Co 0.5 Ni 3.8 alloy (60 mAh) and the battery which presented the best performance was La 0.4 Mg 0.3 Pr 0.3 Al 0.3 Mn 0.4 Co 0.5 Ni 3.8 alloy (53 mAh and 150 cycles). The H 2 capability of absorption was diminished for increased Mg addition and no such effect occurs for Mg 0.7 Pr 0.3 Al 0.3 Mn 0.4 Co 0.5 Ni 3.8 alloy. (author)

  20. Influence of hydrogen content on impact toughness of Zr-2.5Nb pressure tube alloy

    Energy Technology Data Exchange (ETDEWEB)

    Singh, R.N., E-mail: rnsingh@barc.gov.in [Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Viswanathan, U.K.; Kumar, Sunil; Satheesh, P.M.; Anantharaman, S. [Post Irradiation Examination Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Chakravartty, J.K. [Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Stahle, P. [Division of Solid Mechanics, Lund University/LTH, SE22100 Lund (Sweden)

    2011-07-15

    Highlights: > For the first time impact behaviour of Zr-2.5Nb pressure tube material used in Indian Pressurized Heavy Water Reactor (IPHWR) as a function of hydrogen content and temperature is being reported. > The critical hydrogen concentration to cause low energy fracture at 25 and 200 deg. C is suggested. > The impact behaviour is rationalized in terms of hydrogen content, test temperature, microstructural features and state of stress ahead of a crack. - Abstract: Influence of hydrogen content on the impact toughness of Zr-2.5% Nb alloy was examined by carrying out instrumented drop weight tests in the temperature range of 25-250 deg. C using curved Charpy specimens fabricated from unirradiated pressure tubes of Indian Pressurized Heavy Water Reactor (IPHWR). Hydrogen content of the samples was between 10 and 170 ppm by weight (wppm). Sharp ductile-to-brittle-transition behaviour was demonstrated by hydrided materials. The temperature for the onset of transition increased with the increase in the hydrogen content of the specimens. The fracture surfaces of unhydrided specimen exhibited ductile fracture caused by micro void coalescence and tear ridges at lower temperatures and by fibrous fracture at intermediate and at higher temperatures. Except for the samples tested at the upper shelf energy levels, the fracture surfaces of all hydrided samples were suggestive of hydride assisted failure. In most cases the transverse cracks observed in the fracture path matched well with the hydride precipitate distribution and orientation.

  1. Survey research report by the hydrogen occluding alloy utilization development committee; Suiso kyuzo gokin riyo kaihatsu iinkai chosa kenkyu hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1985-03-01

    This report summarizes the FY 1984 survey research results, issued by the hydrogen occluding alloy utilization development committee. The basic property subcommittee is responsible for collecting published data related to the basic properties of metal halides as much as possible, and pigeonholing them to have the data which can contribute to development of the new alloys for basic researches and engineering applications of hydrogen occluding alloys. The subcommittee members have collected these data. The common theme subcommittee has planned to collect the P-C-T diagrams of the hydrogen occluding alloys and new alloys as much as possible, for the designs, development, production and system designs of the hydrogen occluding alloys. The P-C-T diagrams have been collected for a total of 340 types of alloys, which fall into the broad categories of Mg-based, TiFe-based, TiMn-based, other Ti-based, rare-earth-based, Zr-based, Ca-based and others. The analytical methods have been also investigated while collecting P-C-T diagrams. (NEDO)

  2. [The effect of hydrogen peroxide on the electrochemical corrosion properties and metal ions release of nickel-chromium dental alloys].

    Science.gov (United States)

    Wang, Jue; Qiao, Guang-yan

    2013-04-01

    To investigate the effect of hydrogen peroxide on the electrochemical corrosion and metal ions release of nickel-chromium dental alloys. The corrosion resistance of nickel-chromium dental alloys was compared by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PD) methods in artificial saliva after immersed in different concentrations of hydrogen peroxide for 112 h. The metal ions released from nickel-chromium dental alloys to the artificial saliva were detected after electrochemical measurements using inductively coupled plasma mass spectrometry (ICP-MS). The data was statistically analyzed by analysis of variance (ANOVA) using SPSS 13.0 software package. The electrochemical experiment showed that the sequence of polarization resistance in equivalent circuit (Rct), corrosion potential (Ecorr), pitting breakdown potential (Eb), and the difference between Ecorr and Eb representing the "pseudo-passivation" (δE) of nickel-chromium alloys in artificial saliva was 30% alloys to the artificial saliva, and the order of the concentrations of metal ions was 0% corrosion resistance of nickel-chromium dental alloys decrease after immersed in different concentrations of hydrogen peroxide for 112 h. Nickel-chromium dental alloys are more prone to corrosion in the artificial saliva with the concentration of hydrogen peroxide increased, and more metal ions are released in the artificial saliva.

  3. Evaluation of candidate Stirling engine heater tube alloys after 3500 hours exposure to high pressure doped hydrogen or helium

    Science.gov (United States)

    Misencik, J. A.; Titran, R. H.

    1984-01-01

    The heater head tubes of current prototype automotive Stirling engines are fabricated from alloy N-155, an alloy which contains 20 percent cobalt. Because the United States imports over 90 percent of the cobalt used in this country and resource supplies could not meet the demand imposed by automotive applications of cobalt in the heater head (tubes plus cylinders and regenerator housings), it is imperative that substitute alloys free of cobalt be identified. The research described herein focused on the heater head tubes. Sixteen alloys (15 potential substitutes plus the 20 percent Co N-155 alloy) were evaluated in the form of thin wall tubing in the NASA Lewis Research Center Stirling simulator materials diesel fuel fired test rigs. Tubes filled with either hydrogen doped with 1 percent CO2 or with helium at a gas pressure of 15 MPa and a temperature of 820 C were cyclic endurance tested for times up to 3500 hr. Results showed that two iron-nickel base superalloys, CG-27 and Pyromet 901 survived the 3500 hr endurance test. The remaining alloys failed by creep-rupture at times less than 3000 hr, however, several other alloys had superior lives to N-155. Results further showed that doping the hydrogen working fluid with 1 vol % CO2 is an effective means of reducing hydrogen permeability through all the alloy tubes investigated.

  4. Enhanced Hydrogen Storage Kinetics of Nanocrystalline and Amorphous Mg2Ni-type Alloy by Melt Spinning

    Directory of Open Access Journals (Sweden)

    Hui-Ping Ren

    2011-01-01

    Full Text Available Mg2Ni-type Mg2Ni1−xCox (x = 0, 0.1, 0.2, 0.3, 0.4 alloys were fabricated by melt spinning technique. The structures of the as-spun alloys were characterized by X-ray diffraction (XRD and transmission electron microscopy (TEM. The hydrogen absorption and desorption kinetics of the alloys were measured by an automatically controlled Sieverts apparatus. The electrochemical hydrogen storage kinetics of the as-spun alloys was tested by an automatic galvanostatic system. The results show that the as-spun (x = 0.1 alloy exhibits a typical nanocrystalline structure, while the as-spun (x = 0.4 alloy displays a nanocrystalline and amorphous structure, confirming that the substitution of Co for Ni notably intensifies the glass forming ability of the Mg2Ni-type alloy. The melt spinning treatment notably improves the hydriding and dehydriding kinetics as well as the high rate discharge ability (HRD of the alloys. With an increase in the spinning rate from 0 (as-cast is defined as spinning rate of 0 m/s to 30 m/s, the hydrogen absorption saturation ratio ( of the (x = 0.4 alloy increases from 77.1 to 93.5%, the hydrogen desorption ratio ( from 54.5 to 70.2%, the hydrogen diffusion coefficient (D from 0.75 × 10−11 to 3.88 × 10−11 cm2/s and the limiting current density IL from 150.9 to 887.4 mA/g.

  5. The Hydrogen Pickup Behavior for Zirconium-based Alloys in Various Out-of-pile Corrosion Test Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Aomi, M.; Etoh, Y.; Ishimoto, S.; Une, K. [Nippon Nuclear Fuel Development, Co., Ltd., 2163 Narita-cho, Oarai-machi, Ibaraki-ken, 311-1313 (Japan); Ito, K. [Global Nuclear Fuel Japan Co., Ltd., 3-1 Uchikawa 2-chome, Yokosuka-shi, Kanagawa-ken, 239-0836 (Japan)

    2009-06-15

    An acceleration of hydrogen absorption in zirconium alloy claddings at high burnups is one of the most important issues limiting the fuel performance from the viewpoint of cladding integrity. In this context, advanced cladding materials with higher corrosion resistant and lower hydrogen absorption properties have been widely searched in various organizations. In this study, four kinds of zirconium-based alloys, whose in-pile data had been acquired [1,2] were subjected to comprehensive out-of-pile corrosion tests with various temperature and atmosphere conditions in order to investigate the correlation between in-pile and out-of-pile corrosion and hydrogen pick-up behavior, i.e. Zry-2, GNF-Ziron (Zry-2-based alloy with {approx}0.25 wt % of Fe), Hi-FeNi Zircaloy (Zry-2-based alloy with {approx}0.25 wt % of Fe and {approx}0.1 wt% Ni), and VB (Zr-based alloy containing Sn, Cr, and {approx}0.5 wt % of Fe). All the alloys were annealed in RXA condition. The out-of-pile corrosion tests were carried out in three different conditions of 400 deg. C steam, 475 deg. C supercritical water, and 290 deg. C LiOH aqueous solution. In addition to these alloys, several Zry-2-based alloys with various iron contents were tested in 290 deg. C LiOH aqueous solution. Among the four corrosion conditions, the 290 deg. C LiOH aqueous solution test well screened the hydrogen pick-up behavior of the alloys. The hydrogen absorption decreased with higher iron contents in the alloys in both the out-of-pile and in-pile conditions. Especially, the distinct suppression of hydrogen absorption was observed for VB with the highest iron content. The similar dependence of iron content on the hydrogen pick-up fraction was also obtained for the Zry-2-based alloys with different iron contents, which were corroded in the 290 deg. C LiOH aqueous solution condition. As for the corrosion behavior in the 290 deg. C LiOH aqueous solution condition, the weight gains of Zry-2, GNF-Ziron and VB followed the 1

  6. Hydrogen storage properties for Mg–Zn–Y quasicrystal and ternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Xuanli, E-mail: Xuanli.Luo@nottingham.ac.uk; Grant, David M., E-mail: David.Grant@nottingham.ac.uk; Walker, Gavin S., E-mail: Gavin.Walker@nottingham.ac.uk

    2015-10-05

    Highlights: • Quasicrystal (QC) and H-phase alloys were detected in the Zn–Mg–Y samples. • Hydrogen storage properties of Zn–Mg–Y samples were investigated. • Zn{sub 50}Mg{sub 42}Y{sub 8} showed a capacity of 0.9 wt.% and decomposition temperature of 445 °C. - Abstract: Three Zn–Mg–Y alloys with nominal compositions of Zn{sub 50}Mg{sub 42}Y{sub 8} and Zn{sub 60}Mg{sub 30}Y{sub 10} were prepared by induction melting or gas atomisation. XRD and SEM analysis shows samples ZMY-1 and ZMY-2 consisted of multiple phases including icosahedral quasicrystal (QC) i-phase, hexagonal H-phase and Mg{sub 7}Zn{sub 3}, whilst ZMY-3 contained QC only. The hydrogen storage properties of the Zn–Mg–Y quasicrystal and ternary alloys were investigated for the first time. The quasicrystal sample ZMY-3 hydrogenated at 300 °C had 0.3 wt.% capacity and the DSC decomposition peak temperature was 503 °C. Amongst the three samples, the highest hydrogen storage capacity (0.9 wt.%) and the lowest decomposition peak temperature (445 °C) was achieved by sample ZMY-1. The pressure–composition–isotherm (PCI) curve of ZMY-1 sample showed a flat plateau gave a plateau pressure of 3.5 bar at 300 °C, which indicates a lower dehydrogenation enthalpy than MgH{sub 2}.

  7. Platinum-nickel alloy nanoparticles supported on carbon for 3-pentanone hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Lihua, E-mail: lihuazhu@stu.xmu.edu.cn [School of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiang Xi (China); Department of Chemical and Biochemical Engineering, National Engineering Laboratory for Green Productions of Alcohols-Ethers-Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Zheng, Tuo; Yu, Changlin [School of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiang Xi (China); Zheng, Jinbao [Department of Chemical and Biochemical Engineering, National Engineering Laboratory for Green Productions of Alcohols-Ethers-Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Tang, Zhenbiao [School of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiang Xi (China); Zhang, Nuowei [Department of Chemical and Biochemical Engineering, National Engineering Laboratory for Green Productions of Alcohols-Ethers-Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Shu, Qing [School of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiang Xi (China); Chen, Bing H., E-mail: chenbh@xmu.edu.cn [Department of Chemical and Biochemical Engineering, National Engineering Laboratory for Green Productions of Alcohols-Ethers-Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China)

    2017-07-01

    Highlights: • The PtNi/Ni(OH){sub 2}/C catalyst was successfully synthesized at room temperature. • PtNi alloy/C was obtained after PtNi/Ni(OH){sub 2}/C reduced in hydrogen at 300 °C. • Nanostructures of the PtNi catalysts were characterized by numerous techniques. • PtNi alloy/C exhibited high catalytic activity for 3-pentanone hydrogenation. - Abstract: In this work, we prepared the Ni/Ni(OH){sub 2}/C sample at room temperature by hydrazine hydrate reducing method. The galvanic replacement reaction method was applied to deposit platinum on the Ni/Ni(OH){sub 2} nanoparticles, to prepare the PtNi/Ni(OH){sub 2}/C catalyst. The catalyst of platinum-nickel alloy nanoparticles supported on carbon (signed as PtNi/C) was obtained by the thermal treatment of PtNi/Ni(OH){sub 2}/C in flowing hydrogen at 300 °C for 2 h. The size, nanostructure, surface properties, Pt and Ni chemical states of the PtNi/C catalyst were analyzed using powder X-ray diffraction (XRD), transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM), high-angle annular dark-field scanning TEM (HAADF-STEM) and elemental energy dispersive X-ray spectroscopy (EDS) line scanning, X-ray photoelectron spectroscopy (XPS) and high-sensitivity low-energy ion scattering spectroscopy (HS-LEIS) techniques. The as-synthesized PtNi/C catalyst showed enhanced catalytic performance relative to the Ni/Ni(OH){sub 2}/C, Ni/C, Pt/C and PtNi/Ni(OH){sub 2}/C catalysts for 3-pentanone hydrogenation due to electron synergistic effect between Pt and Ni species in the PtNi/C catalyst. The PtNi/C catalyst also had exceling stability, with industrial application value.

  8. Report on investigations and studies on development of materials for hydrogen absorbing alloys; Suiso kyuzo gokin no zairyo no kaihatsu ni kansuru chosa kenkyu hokokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1984-03-01

    This paper describes investigations and studies on hydrogen absorbing alloy materials and the technologies to utilize them. In the investigations and studies, literatures were collected and put into order, questionnaire surveys were performed and analyzed, lecture meetings and panel discussions were held, and the discussion results were summarized. In the present status of developing hydrogen absorbing alloys, the current status of and problems in developing such hydrogen absorbing alloys as Ti-based, Mg-based, and rare earth-based alloys were put into order. Discussions were given on prospects of possibilities of developing new alloys, making them amorphous, and putting them into mass production. In the current status of developing the utilizing technologies, such technologies as hydrogen storage systems and heat pumps were put into order and discussed. With regard to problems in hydrogen absorbing alloys, discussions were given on alloy weight, pulverization, activation, heat conductivity, and alloy costs. In discussing the safety, discussions were given on the safety and compliance with related laws and regulations relative to hydrogen transportation using a great amount of hydrogen absorbing alloys, their storage, and heat storage systems. In addition, questionnaire surveys were carried out with an objective to identify the status of developing hydrogen absorbing alloys and needs from the industries. (NEDO)

  9. BEHAVIOR OF THERMAL SPRAY COATINGS AGAINST HYDROGEN ATTACK

    OpenAIRE

    Vargas, Fabio; Latorre, Guillermo; Uribe, Iván

    2003-01-01

    The behavior of nickel and chrome alloys applied as thermal spray coatings to be used as protection against embrittlement by hydrogen is studied. Coatings were applied on a carbon steel substrate, under conditions that allow obtain different crystalline structures and porosity levels, in order to determine the effect of these variables on the hydrogen permeation kinetics and as a protection means against embrittlement caused this element. In order to establish behaviors as barriers and protec...

  10. On Diffusion and Permeation

    KAUST Repository

    Peppin, Stephen S. L.

    2009-01-01

    concentrations they form a nearly rigid porous glass through which the fluid permeates. The theoretically determined pressure drop is nonlinear in the diffusion regime and linear in the permeation regime, in quantitative agreement with experimental measurements

  11. First-principles calculations of the interaction between hydrogen and 3d alloying atom in nickel

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wenguan, E-mail: liuwenguan@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Chinese Academy of Sciences, Shanghai 201800 (China); Qian, Yuan; Zhang, Dongxun [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Chinese Academy of Sciences, Shanghai 201800 (China); Liu, Wei, E-mail: liuwei@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Chinese Academy of Sciences, Shanghai 201800 (China); Han, Han [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Chinese Academy of Sciences, Shanghai 201800 (China)

    2015-10-15

    Knowledge of the behavior of hydrogen (H) in Ni-based alloy is essential for the prediction of Tritium behavior in Molten Salt Reactor. First-principles calculations were performed to investigate the interaction between H and 3d transition metal (TM) alloying atom in Ni-based alloy. H prefers the octahedral interstitial site to the tetrahedral interstitial site energetically. Most of the 3d TM elements (except Zn) attract H. The attraction to H in the Ni–TM–H system can be mainly attributed to the differences in electronegativity. With the large electronegativity, H and Ni gain electrons from the other TM elements, resulting in the enhanced Ni–H bonds which are the source of the attraction to H in the Ni–TM–H system. The obviously covalent-like Cr–H and Co–H bindings are also beneficial to the attraction to H. On the other hand, the repulsion to H in the Ni–Zn–H system is due to the stable electronic configuration of Zn. We mainly utilize the results calculated in 32-atom supercell which corresponds to the case of a relatively high concentration of hydrogen. Our results are in good agreement with the experimental ones.

  12. Hydrothermal Synthesis of Co-Ru Alloy Particle Catalysts for Hydrogen Generation from Sodium Borohydride

    Directory of Open Access Journals (Sweden)

    Marija Kurtinaitienė

    2013-01-01

    Full Text Available We report the synthesis of μm and sub-μm-sized Co, Ru, and Co-Ru alloy species by hydrothermal approach in the aqueous alkaline solutions (pH ≥ 13 containing CoCl2 and/or RuCl3, sodium citrate, and hydrazine hydrate and a study of their catalytic properties for hydrogen generation by hydrolysis of sodium borohydride solution. This way provides a simple platform for fabrication of the ball-shaped Co-Ru alloy catalysts containing up to 12 wt% Ru. Note that bimetallic Co-Ru alloy bowls containing even 7 at.% Ru have demonstrated catalytic properties that are comparable with the ones of pure Ru particles fabricated by the same method. This result is of great importance in view of the preparation of cost-efficient catalysts for hydrogen generation from borohydrides. The morphology and composition of fabricated catalyst particles have been characterized using scanning electron microscopy, energy dispersive X-ray diffraction, and inductively coupled plasma optical emission spectrometry.

  13. Part of the hydrogen in the intergranular crack by stress corrosion in primary circuit for the 600 and 690 nickel base alloys

    International Nuclear Information System (INIS)

    Odemer, G.; Coudurier, A.; Jambon, F.; Chene, J.; Odemer, G.; Coudurier, A.; Chene, J.

    2007-01-01

    The aim of this study is, in a first part, to characterize the hydrogen embrittlement sensitivity of the 600 and 690 based alloys in order to better understand the hydrogen role in the stress corrosion mechanism which appears in theses alloys in the primary circuit of the PWR type reactors. The authors studies how the hydrogen embrittlement is resulting from an interaction between the hydrogen and the plastic deformation. (A.L.B.)

  14. Novel surface treatment for hydrogen storage alloy in Ni/MH battery

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xiangyu; Ma, Liqun; Ding, Yi; Yang, Meng; Shen, Xiaodong [College of Materials Science and Engineering, Nanjing University of Technology, 5 Xinmofan Road, Nanjing 210009 (China)

    2009-05-15

    A novel surface treatment for the MlNi{sub 3.8}Co{sub 0.75}Mn{sub 0.4}Al{sub 0.2} (La-rich mischmetal) hydrogen storage alloy has been carried out by using an aqueous solution of HF and KF with a little addition of KBH{sub 4}. The results of scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) showed that rough surface was formed and Al was partly dissolved into the solution after the treatment. The result of XPS indicated the formation of Ni{sub 3}B and LaF{sub 3} compounds on the alloy surface by the treatment. The probable chemical reaction mechanism for the surface treatment was introduced. The treatment resulted in significant improvements in the activation property, discharge capacity and cycle life of the alloy, especially the high rate dischargeability (HRD). The HRD of the treated alloy still remained 54.9% while that of the untreated one was only 15.1% at a discharge current density of 1200 mA/g. (author)

  15. Study of hydrogenation for pulverization of rare earth alloys with Nb for metal hydride electrodes

    International Nuclear Information System (INIS)

    Ferreira, Eliner Affonso

    2013-01-01

    In this work were studied La ,7 Mg 0,3 Al 0,3 Mn 0,4 Co (0.5-x) NbxNi 3.8 (x= 0 - 0.5) and La 0,7 Mg 0,3 Al 0,3 Mn 0.4 Nb (05+x) Co 0,5 Ni (3.8-x) . (x=0.3; 0.5;1.3) alloys for negative electrodes of the Nickel-Metal Hydride batteries. The hydrogenation of the alloys was performed varying pressing of H 2 (2 and 9 bar). The discharge capacity of the nickel-metal hydride batteries were analyzed in the Arbin BT-4 electrical test equipment. The as-cast alloys were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and X-Ray diffraction. The increasing Niobium addition in the alloys decreased cycle life and the maximum discharge capacity of the batteries. The maximum discharge capacity was obtained with the La .7 Mg 0.3 Al 0.3 Mn 0,4 Co 0.5 Ni 3.8 (45.36 mAh) and the battery which presented the best performance was La .7 Mg 0.3 Al 0.3 Mn 0.4 Co 0.5 Nb 0.1 Ni 3.8 (44.94 mAh). (author)

  16. Influence of dissolved hydrogen on oxide film and PWSCC of Alloy 600 in PWR primary water

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, Tomokazu; Totsuka, Nobuo; Nakajima, Nobuo [Institute of Nuclear Safety System Inc., Mihama, Fukui (Japan)

    2001-09-01

    In order to investigate the influence of dissolved hydrogen (DH) on the corrosion behavior and PWSCC of Alloy 600 in primary water of PWR under actual operating temperature range, we carried out electrochemical polarization measurement, repassivation test, analysis of the oxide film on the alloy by AES, XPS and PWSCC test. In all cases, the content of DH was changed from 0 to 45 cc/kgH{sub 2}O. The anodic polarization curve reveals that the peak current density increases with increasing DH. The result of the repassivation test shows that the repassivation rate decreases with increasing DH, and the changes of the above two become larger between 11 and 22 cc/kgH{sub 2}O of DH. According to the results of oxide film analysis, it is seen that the oxide films formed below 11 cc/kgH{sub 2}O of DH are relatively thick and rich in Ni, but those formed at higher DH contents are relatively thin and rich in Cr and Fe. The susceptibility of the alloy to PWSCC has a peak at 11 cc/kgH{sub 2}O of DH, which reveals that the property of the oxide film may play important role in PWSCC of alloy. (author)

  17. Solubility and partitioning of hydrogen in meta-stable ZR-based alloys used in the nuclear industry

    International Nuclear Information System (INIS)

    Khatamian, D.

    1998-11-01

    Terminal solubility and partitioning of hydrogen in Zr-Nb alloys with different Nb concentrations were examined using differential scanning calorimetry and hot vacuum extraction mass spectrometry. Specimens were charged to different concentrations of hydrogen and annealed at 1123 K to generate a two-phase structure consisting of α-Zr (Zr-0.6 wt.% Nb) and meta-stable β-Zr (Zr-20 wt.% Nb) within the alloy. Specimens were aged at 673 and 773 K for up to 1000 h to evaluate the effect of the decomposition of the meta-stable β-Zr to α-Zr + β-Nb on the solubility limit. The results show that the solubility limit for hydrogen in the annealed Zr-Nb alloys is higher than in unalloyed Zr and that the solubility limit increases with the Nb concentration of the alloy. They also show that the hydrogen solubility limits of the completely aged Zr-Nb alloys are similar and approach the values for pure α-Zr. The solubility ratio of hydrogen in β-Zr (Zr-20 wt.% Nb) to that in α-Zr (Zr-0.6 wt.% Nb) was found to range from 9 to 7 within the temperature range of 520 to 580 K. (author)

  18. Influence of dissolved hydrogen and temperature on primary water stress corrosion cracking of mill annealed alloy 600

    Energy Technology Data Exchange (ETDEWEB)

    Totsuka, Nobuo; Nishikawa, Yoshito [Inst. of Nuclear Safety System Inc., Mihama, Fukui (Japan); Nakajima, Nobuo

    2002-09-01

    The influence of dissolved hydrogen and temperature on primary water stress corrosion cracking (PWSCC) of alloy 600 was experimentally studied at temperature ranging from 310 to 360degC and hydrogen contents ranging from 0 to 4 ppm using slow strain rate tensile technique (SSRT) and constant load tensile test. As a result, it was revealed that the PWSCC susceptibility of alloy 600 has a maximum near 3 ppm of dissolved hydrogen at 360degC and the peak shifts to 1 ppm at 320degC. The mechanism of the peak shift is not clear yet, however, it is possibly explained by the change of absorbed hydrogen in the metal caused by the change of hydrogen recombination reaction and/or change of the surface film. (author)

  19. New experimental set-up and procedure for analyzing the dynamics of permeation of H2(g) across Pd-based metallic membranes

    International Nuclear Information System (INIS)

    Decaux, C.; Millet, P.; Decaux, C.

    2006-01-01

    Hydrogen permeation through metallic membranes is an industrial process used for purification purposes. Palladium-based alloys are generally used as permeation materials at operating temperatures above the critical value so that the metal-H system remains monophasic and that diffusion proceeds at sufficient rate. In state of the art systems, metallic membranes with typical thickness of a few tens of microns are used and rate limitation are generally attributed to atomic H transport by diffusion. Because of cost considerations, it is necessary to reduce the thickness of these membranes. In the micron thick range, surface contributions are expected to become rate determining, or at least to play an increasing role. Further, when the membrane is used on the exit side of a gas reformer to directly extract hydrogen, corrosion problems are expected to occur on the upstream side of the membrane. For all these reasons, there is a need to separately measure surface and bulk (diffusion) rate contributions to the overall permeation flux. A new experimental equipment has been specifically designed for this purpose. This setup can be operated in two different modes: for sorption or permeation experiments. In a typical sorption experiment, the metallic membrane is disposed in the reaction chamber and hydrogen is allowed to react from both side of the surface. This procedure allows the separate measurement of surface absorption and desorption resistances associated with the chemisorption step. In a typical permeation experiment, the membrane is mounted between two volume chambers, a pressurized hydrogen source reservoir and an empty sink reservoir. Initially, a difference of pressure is set between the two reservoirs. When the valve of the source tank is opened, H 2 (g) flows to the membrane and permeation proceeds until pressure reaches an equilibrium value. In both experimental configurations, gas pressure transients are synchronously sampled all along the experiment

  20. An investigation on hydrogen storage kinetics of nanocrystalline and amorphous Mg2Ni1-xCox (x = 0-0.4) alloy prepared by melt spinning

    International Nuclear Information System (INIS)

    Zhang Yanghuan; Li Baowei; Ren Huipin; Ding Xiaoxia; Liu Xiaogang; Chen Lele

    2011-01-01

    Research highlights: → The investigation of the structures of the Mg 2 Ni 1-x Co x (x = 0, 0.1, 0.2, 0.3, 0.4) alloys indicates that a nanocrystalline and amorphous structure can be obtained in the experiment alloys by melt spinning technology. The substitution of Co for Ni facilitates the glass formation in the Mg 2 Ni-type alloy. And the amorphization degree of the alloys visibly increases with increasing Co content. → Both the melt spinning and Co substitution significantly improve the hydrogen storage kinetics of the alloys. The hydrogen absorption saturation ratio (R t a ) and hydrogen desorption ratio (R t d ) as well as the high rate discharge ability (HRD) increase with rising spinning rate and Co content. The hydrogen diffusion coefficient (D), the Tafel polarization curves and the electrochemical impedance spectra (EIS) measurements show that the electrochemical kinetics notably increases with rising spinning rate and Co content. → Furthermore, all the as-spun alloys, when the spinning rate reaches to 30 m/s, have nearly same hydrogen absorption kinetics, indicating that the hydrogen absorption kinetics of the as-spun alloy is predominately controlled by diffusion ability of hydrogen atoms. - Abstract: In order to improve the hydrogen storage kinetics of the Mg 2 Ni-type alloys, Ni in the alloy was partially substituted by element Co, and melt-spinning technology was used for the preparation of the Mg 2 Ni 1-x Co x (x = 0, 0.1, 0.2, 0.3, 0.4) hydrogen storage alloys. The structures of the as-cast and spun alloys are characterized by XRD, SEM and TEM. The hydrogen absorption and desorption kinetics of the alloys were measured by an automatically controlled Sieverts apparatus. The electrochemical hydrogen storage kinetics of the as-spun alloys is tested by an automatic galvanostatic system. The hydrogen diffusion coefficients in the alloys are calculated by virtue of potential-step method. The electrochemical impedance spectrums (EIS) and the Tafel

  1. Effect of hydrogen charging on the mechanical properties of medium strength aluminium alloys 2091 and 2014

    DEFF Research Database (Denmark)

    Bandopadhyay, A.; Ambat, Rajan; Dwarakadasa, E.S.

    1992-01-01

    Cathodic hydrogen charging in 3.5% NaCl solution altered the mechanical properties of 2091-T351 (Al-Cu-Li-Mg-Zr) determined by a slow (10(-3)/s) strain rate tensile testing technique. UTS and YS decreased in the caw of 2091-T351 and 2014-T6(Al-Cu-Mn-Si-Mg) with increase in charging current density....... Elongation showed a decrease with increase in charging current density for both the alloys. However, elongation occurring throughout the gauge length in uncharged specimens changed over to localized deformation, thus increasing the reduction in area in charged specimens. A transition in fracture mode from...

  2. ALTERNATIVE MATERIALS TO PD MEMBRANES FOR HYDROGEN PURIFICATION

    Energy Technology Data Exchange (ETDEWEB)

    Korinko, P; T. Adams

    2008-09-12

    Development of advanced hydrogen separation membranes in support of hydrogen production processes such as coal gasification and as front end gas purifiers for fuel cell based system is paramount to the successful implementation of a national hydrogen economy. Current generation metallic hydrogen separation membranes are based on Pd-alloys. Although the technology has proven successful, at issue is the high cost of palladium. Evaluation of non-noble metal based dense metallic separation membranes is currently receiving national and international attention. The focal point of the reported work was to evaluate two different classes of materials for potential replacement of conventional Pd-alloy purification/diffuser membranes. Crystalline V-Ni-Ti and Amorphous Fe- and Co-based metallic glass alloys have been evaluated using gaseous hydrogen permeation testing techniques.

  3. Investigation on the Structure and Electrochemical Properties of La-Ce-Mg-Al-Ni Hydrogen Storage Alloy

    Directory of Open Access Journals (Sweden)

    Yuqing Qiao

    2013-01-01

    Full Text Available Structure and electrochemical characteristics of La0.96Ce0.04Mg0.15Al0.05Ni2.8 hydrogen storage alloy have been investigated. X-ray diffraction analyses reveal that the La0.96Ce0.04Mg0.15Al0.05Ni2.8 hydrogen storage alloy consisted of a (La, MgNi3 phase with the rhombohedral PuNi3-type structure and a LaNi5 phase with the hexagonal CaCu5-type structure. TEM shows that the alloy is multicrystal with a lattice space 0.187 nm. EDS analyse shows that the content of Mg is 3.48% (atom which coincide well with the designed composition of the electrode alloy. Electrochemical investigations show that the maximum discharge capacity of the alloy electrode is 325 mAh g−1. The alloy electrode has higher discharge capacity within the discharge current density span from 60 mA g−1 to 300 mA g−1. Electrochemical impedance spectroscopy measurements indicate that the charge transfer resistance RT on the alloy electrode surface and the calculated exchange current density I0 are 0.135 Ω and 1298 mA g−1, respectively; the better eletrochemical reaction kinetic of the alloy electrode may be responsible for the better high-rate dischargeability.

  4. Isotope effects in the diffusion of hydrogen and deuterium in ferromagnetic binary alloys of the Cu3Au type

    International Nuclear Information System (INIS)

    Hirscher, M.; Maier, C.U.; Schwendemann, B.; Kronmueller, H.

    1989-01-01

    The diffusion behaviour of hydrogen and deuterium at low temperatures was investigated in ordered and disordered alloys of Ni 3 Fe, Ni 3 Mn, and Fe 3 Pt by means of magnetic after-effect (MAE) measurements. After hydrogen charging all specimens show characteristic MAE relaxation spectra, which can be described taking into account the different octahedral positions of the hydrogen atoms in the Cu 3 Au structure. The observed isotope effect can qualitatively be explained by a thermally activated tunnelling process of the hydrogen isotopes. (orig.)

  5. Removing of oxides from Fe-Ni alloys by hydrogen plasma treatment

    International Nuclear Information System (INIS)

    Vesel, A.; Drenik, A.; Mozetic, M.

    2007-01-01

    Plasma wall interaction is one of the key issues in fusion research for ITER application. The first-wall materials in tokamaks and in other high temperature plasma reactors are subject to and to continuous degradation due to the ion bombardment. Furthermore the release of the eroded wall material leads to their redeposition to other parts of the fusion reactor and they can be even transported into the core plasma where they cause dilution of the plasma fuel and cooling of the plasma itself. One possible solution for removal of deposits formed during operation of the fusion devices is oxygen plasma treatment. A drawback of the oxygen plasma is that it causes formation of oxides on the surface of the materials. These oxides can be reduced by further hydrogen plasma treatment. A study on reduction of an oxide layer from Fe-Ni alloys was performed. The samples were exposed to low pressure weakly ionized hydrogen plasma for different periods. A density of hydrogen plasma was 8x10 15 m -3 , an electron temperature was 6 eV, and a degree of dissociation was about 30%. After plasma treatment the samples were analyzed by Auger Electron Spectroscopy (AES). The results showed that the complete reduction of an initial oxide layer with the thickness of about 30 nm occurred after 20 s of exposure to hydrogen plasma, when AES showed no more oxygen on the surface of Fe-Ni alloy. During the exposure of the samples to the plasma their temperature was measured. The temperature first rised with time, reached the maximum value, and than dropped as soon as the layer of an oxide on the surface was reduced. (author)

  6. Effect of dissolved hydrogen on Schottky barrier height of Fe-Cr alloy heterojunction

    Science.gov (United States)

    Berahim, A. N.; Zaharudin, M. Z.; Ani, M. H.; Arifin, S. K.

    2018-01-01

    The presence of water vapour at high temperature oxidation has certain effects on ferritic alloy in comparison to dry environment. It is hypothesized that at high temperature; water vapour provides hydrogen, which will dissolve into ferritic alloy substrate and altering their electronic state at the metal-oxide interface. This work aimed to clarify the change in electronic state of metal-oxide heterojunction with the presence of hydrogen/water vapour. In this study, the Schottky Barrier (SB) was created by sputtering Cr2O3 onto prepared samples by using RF Magnetron sputtering machine. The existence of Fe/Cr2O3 junction was characterized by using XRD. The surfaces were observed by using Optical Microscope (OM) and Scanning Electron Microscope (SEM). The samples were then exposed in dry and humid condition at temperature of 473 K and 1073 K. In dry condition, 100% Ar is flown inside the furnace, while in wet condition mixture of 95% Ar and 5% H was used. I-V measurement of the junction was done to determine the Schottky Barrier Height(SBH) of the samples in the corresponding ambient. The results show that in Fe/Cr2O3 junction, with presence of hydrogen at temperature 473 K; the SBH was reduced by the scale factor of 1.054 and at 1073 K in wet ambient by factor of 1.068. Meanwhile, in Fe-Cr/Cr2O3 junction with presence of hydrogen, the value of SBH was increased by scale factor of 1.068 at temperature 473 K while at 1073 K, the SBH also increased by factor of 1.009.

  7. Feasibility study of hydrogenated amorphous alloys as high-damping materials

    International Nuclear Information System (INIS)

    Mizubayashi, H.; Ishikawa, Y.; Tanimoto, H.

    2004-01-01

    The hydrogen internal friction peak (HIFP) and the tensile strength, σ f , in amorphous (denoted by 'a') Zr 60-y Cu 30 Al 10 Si y (y=0, 1) and a-Zr 40 Cu 50-x Al 10 Si x (x=0, 1) alloys are investigated as a function of the hydrogen concentration, C H . The drastic increase in the peak temperature, T p , of the HIFP due to the Si addition by 1 at.% is found for the a-Zr 40 Cu 49 Al 10 Si 1 , where the decrease in 1/τ 0 (τ 0 denotes the pre-exponential factor of the relaxation time for the HIFP) from 1.5x10 12 s -1 to 3.0x10 10 s -1 is observed. On the other hand, the increase in T p due to the Si addition by 1 at.% is much smaller for a-Zr 59 Cu 30 Al 10 Si 1 , where 1/τ 0 for the HIFP in a-Zr 60 Cu 30 Al 10 is already as low as that for a- Zr 40 Cu 49 Al 10 Si 1 . For the HIFP with the peak height, Q p -1 , beyond 1x10 -2 , Q p -1 in the as-charged state decreases after heating to about 380 K because of the hydrogen induced structural relaxation (HISR). The HIFP with Q p -1 below 1x10 -2 is rather stable against the HISR. It is suggested that the highly anisotropic local strain around a hydrogen atom is responsible for the very high Q p -1 and the HISR. For the high-strength and high-damping performance, σ f is higher than 1.5 GPa and Q p -1 after the HISR is slightly lower than 1x10 -2 for the present Zr-Cu-Al-(Si) a-alloys

  8. Influence of oxygen on hydrogen storage and electrode properties for micro-designed V-based battery alloys

    Energy Technology Data Exchange (ETDEWEB)

    Tsukahara, M.; Takahashi, K.; Isomura, A. [Mater. R and D Co., Ltd., Aichi (Japan). IMRA; Sakai, T. [Osaka National Research Institute, Midorigaoka, Ikeda-shi, Osaka, 563 (Japan)

    1998-01-30

    The influence of oxygen on micro-structure, hydrogen storage and electrode properties were investigated for the alloy V{sub 3}TiNi{sub 0.56}Co{sub 0.14}Nb{sub 0.047}Ta{sub 0.047}. Since titanium in the alloy worked as a deoxidizer to form the oxide phase, the alloy preserved a large hydrogen capacity in the oxygen concentration range below 5000 mass ppm. More oxygen than 6000 mass ppm caused a remarkable contraction of the unit cell of the vanadium-based main phase and then a decrease in the hydrogen storage capacity. The contraction was accompanied by the precipitation of the Ti-based oxide phase. (orig.) 15 refs.

  9. Hydrogen storage alloy and alkaline battery employing it; Suiso kyuzo gokin denkyoku to sorewo mochiita arukari niji denchi

    Energy Technology Data Exchange (ETDEWEB)

    Ono, T. [Furukawa Electric Co. Ltd., Tokyo (Japan); Furukawa, J. [The Furukawa Battery Co. Ltd., Yokohama (Japan)

    1997-01-28

    The invented hydrogen storage alloy electrode is produced in the following way: The hydrogen storage alloy powder is mixed with conductive material and rubber-like elastomer. A certain amount of viscosity modifier aqueous solution such as aqueous solution of carboxymethylcellulose is added to the said mixture to prepare a mixed paste. The said paste is dried and rolled after being filled in the current collector to be held by the current collector. The rubber-like elastomer has a strong bonding force, though it is soft. Both hydrophobic and hydrophilic groups are contained in its molecule. Example of such material is a partly fluorinated or chlorinated acrylonitrile-butadiene rubber. The addition of fluorine or chlorine atom is done to its double bond. The addition of the rubber-like elastomer is controlled to 0.05 - 10 wt% of hydrogen storage alloy powder to suppress the elevation of inner-battery pressure at the time of overcharge. 2 tabs.

  10. Deformation and fracture of aluminum-lithium alloys: The effect of dissolved hydrogen

    Science.gov (United States)

    Rivet, F. C.; Swanson, R. E.

    1990-01-01

    The effects of dissolved hydrogen on the mechanical properties of 2090 and 2219 alloys are studied. The work done during this semi-annual period consists of the hydrogen charging study and some preliminary mechanical tests. Prior to SIMS analysis, several potentiostatic and galvanostatic experiments were performed for various times (going from 10 minutes to several hours) in the cathodic zone, and for the two aqueous solutions: 0.04N of HCl and 0.1N NaOH both combined with a small amount of As2O3. A study of the surface damage was conducted in parallel with the charging experiments. Those tests were performed to choose the best charging conditions without surface damage. Disk rupture tests and tensile tests are part of the study designed to investigate the effect of temperature, surface roughness, strain rate, and environment on the fracture behavior. The importance of the roughness and environment were shown using the disk rupture test as well as the importance of the strain rate under hydrogen environment. The tensile tests, without hydrogen effects, have not shown significant differences between low and room temperature.

  11. Hydrogen absorption-desorption properties of Ti0.32Cr0.43V0.25 alloy

    International Nuclear Information System (INIS)

    Cho, Sung-Wook; Shim, Gunchoo; Choi, Good-Sun; Park, Choong-Nyeon; Yoo, Jeong-Hyun; Choi, Jeon

    2007-01-01

    Ti 0.32 Cr 0.43 V 0.25 alloy specimens were heat treated, and its various hydrogen storage properties were measured at 303 K to examine its potential as a hydrogen storage material. The heat treatment improved not only the total and the effective hydrogen storage capacities, but also the plateau flatness. The heat of hydride formation was approximately -36 kJ/mol H 2 . The effective hydrogen storage capacity remained at approximately 2 wt% after 1000 cycles of pressure swing cyclic tests. The hydrogen storage capacity could be recovered almost to the initial state by reactivating the alloy. The hydrogen absorption rate increased with the repetition of cycling for the first several cycles and remained almost constant afterward. At the 504th cycle, more than 98% of the hydrogen was absorbed within the first 2 min. X-ray diffraction (XRD) patterns showed that the crystal structure of the alloy became more amorphous as the number of cycles increased

  12. Characterization of hydrogenation behavior on Mo-modified Zr-Nb alloys as nuclear fuel cladding materials

    International Nuclear Information System (INIS)

    Yang, H.L.; Shibukawa, S.; Abe, H.; Satoh, Y.; Matsukawa, Y.; Kido, T.

    2014-01-01

    The effects of Mo in Zr-Nb alloys are investigated in terms of their mechanical properties associated with microstructure, as well as their behavior under hydrogen environment. Zr-Nb-Mo alloys were fabricated by arc melting and subsequently cold rolling and annealing below the eutectoid temperature. Hydrogen was absorbed in a furnace under argon and hydrogen gas flow environment at high temperature. X-Ray diffraction, electron backscatter diffraction, and tensile test were jointly utilized to carry out detailed microstructural characterization and mechanical properties. Results showed that fcc-δ-ZrH 1.66 was formed in all hydrogen-absorbed alloys, and the amount of hydride enhanced with increasing of hydrogen content. In addition, it was clear that δ-ZrH 1.66 was precipitated both in grain boundary and interior, and preferential precipitation was observed on the habit planes of (0001) and {101-bar7}. Moreover, the strengthening effect by Mo addition was observed. The ductility loss by hydrogen absorption was found from fracture surface observation. Large area cleavage facets were found in Mo-free specimen, and less cleavage facets was observed in Mo-containing specimen, showing an appropriate addition of Mo can increase the tolerance to hydrogen embrittlement. (author)

  13. States and transport of hydrogen in the corrosion process of an AZ91 magnesium alloy in aqueous solution

    International Nuclear Information System (INIS)

    Chen Jian; Wang Jianqiu; Han Enhou; Dong Junhua; Ke Wei

    2008-01-01

    Mott-Schottky measurement and secondary ion mass spectroscopy (SIMS) were used to investigate the states and transport of hydrogen during the corrosion behavior of an AZ91 magnesium alloy in 0.1 M sodium sulfate solution. The results showed that when samples were immersed or charged in solution, hydrogen atoms diffused into the film and reacted with vacancy to cause the increases of the carrier concentration (excess electron or hole carrier) and diffusion rate of hydrogen. Some hydrogen atoms diffused to interior of matrix and enriched in β phase while others resorted in the corrosive film. With the increase of immersion or charging time, magnesium hydride would be brittle fractured when the inner stress caused by hydrogen pressure and expansion stress of formation of magnesium hydride was above the fracture strength, which provided the direct experimental evidence of the hydrogen embrittlement (HE) mechanism of magnesium and its alloys. After immersion in solution, the transfer of excess electrons to the interfaces of corrosion film and solution would destroy the charge equilibrium in the film and stimulate the adsorption of SO 4 2- , which resulted in the initiation of localized corrosion; after cathodic charging and then immersion, the enrichment of hydrogen atoms at interior of corrosion film would combine into hydrogen gas to form high pressure and result in the rupture of corrosion film, and localized corrosion initiated and developed at surface. Therefore, localized corrosion nucleated earlier on the charged samples than on the uncharged samples. Hydrogen invasion accelerated the corrosion of matrix

  14. Role of hydrogen in the intergranular cracking mechanism by stress corrosion in primary medium of nickel based alloys 600 and 690

    International Nuclear Information System (INIS)

    Odemer, G.; Coudurier, A.; Jambon, F.; Chene, J.; Odemer, G.; Coudurier, A.; Chene, J.

    2007-01-01

    The aim of this work is to characterize the sensitivity to hydrogen embrittlement of alloys 600 and 690 in order to better understand the eventual role of hydrogen in the stress corrosion mechanism which affects these alloys when they are exposed in PWR primary medium. (O.M.)

  15. Improved rapidly-quenched hydrogen-absorbing alloys for development of improved-capacity nickel metal hydride batteries

    Science.gov (United States)

    Ise, Tadashi; Hamamatsu, Takeo; Imoto, Teruhiko; Nogami, Mitsuzo; Nakahori, Shinsuke

    The effects of annealing a rapidly-quenched hydrogen-absorbing alloy with a stoichiometric ratio of 4.76 were investigated concerning its hydrogen-absorbing properties, crystal structure and electrochemical characteristics. Annealing at 1073 K homogenized the alloy microstructure and flattened its plateau slope in the P-C isotherms. However, annealing at 1273 K segregated a second phase rich in rare earth elements, increased the hydrogen-absorbing pressure and decreased the hydrogen-absorbing capacity. As the number of charge-discharge cycles increases, the particle size distribution of the rapidly-quenched alloy became broad due to partial pulverization. However, particle size distribution of the rapidly-quenched, annealed, alloy was sharp, since the annealing homogenized the microstructure, thereby improving the cycle characteristics. A high-capacity rectangular nickel metal hydride battery using a rapidly-quenched, annealed, surface-treated alloy for the negative electrode and an active material coated with cobalt compound containing sodium for the positive electrode was developed. The capacity of the resulting battery was 30% greater than that of a conventional battery.

  16. Effect of hydrogen oxygen and nitrogen, on the tendency of welded joints of titanium alloys to moderate failure

    International Nuclear Information System (INIS)

    Gorshkov, A.I.; Matyushin, B.A.

    1976-01-01

    The admissible limits have been defined of gaseous impurities content in the metal of welded joints of titanium alloys, with due accout for the phase composition and alloying system. The proposed procedure of testing disk specimens most adequately simulates the behavior of welded joints in full-scale strures. The tests lasting 2.5 to 3 years permit to consider the effect of temporal processes (hydrogen diffusion, relaxation of stresses, phase transformations, etc.) on the durability of a weld. The hydrogen content in the metal of welded joints of OT4 alloy should not exceed 0.008%, that of VT14 alloy should not exceed 0.008%, and that of VT20 alloy should not exceed 0.015% (at an oxygen content of no more than 0.15% and a nitrogen content of no more than 0.03%), the oxygen content being 0.25%, 0.2% and 0.2%, respectxvely (at a hydrogen content of no more than 0.008% and a nitrogen of no more than 0.03%), ;nd the nitrogen content being 0.1%, 0.06% and 0.08%, respectively (at hydrogen content of no more than 0.008% and an oxygen content of no more than 0.15%

  17. Applications of ion implantation for modifying the interactions between metals and hydrogen gas

    Science.gov (United States)

    Musket, R. G.

    1989-04-01

    Ion implantations into metals have been shown recently to either reduce or enhance interactions with gaseous hydrogen. Published studies concerned with modifications of these interactions are reviewed and discussed in terms of the mechanisms postulated to explain the observed changes. The interactions are hydrogenation, hydrogen permeation, and hydrogen embrittlement. In particular, the results of the reviewed studies are (a) uranium hydriding suppressed by implantation of oxygen and carbon, (b) hydrogen gettered in iron and nickel using implantation of titanium, (c) hydriding of titanium catalyzed by implanted palladium, (d) tritium permeation of 304L stainless steel reduced using selective oxidation of implanted aluminum, and (e) hydrogen attack of a low-alloy steel accelerated by implantation of helium. These studies revealed ion implantation to be an effective method for modifying the interactions of hydrogen gas with metals.

  18. Applications of ion implantation for modifying the interactions between metals and hydrogen gas

    International Nuclear Information System (INIS)

    Musket, R.G.

    1989-01-01

    Ion implantations into metals have been shown recently to either reduce or enhance interactions with gaseous hydrogen. Published studies concerned with modifications of these interactions are reviewed and discussed in terms of the mechanisms postulated to explain the observed changes. The interactions are hydrogenation, hydrogen permeation and hydrogen embrittlement. In particular, the results of the reviewed studies are 1. uranium hydriding suppressed by implantation of oxygen and carbon, 2. hydrogen gettered in iron and nickel using implantation of titanium, 3. hydriding of titanium catalyzed by implanted palladium, 4. tritium permeation of 304L stainless steel reduced using selective oxidation of implanted aluminum, and 5. hydrogen attack of a low-alloy steel accelerated by implantation of helium. These studies revealed ion implantation to be an effective method for modifying the interactions of hydrogen gas with metals. (orig.)

  19. A study on the Development of Zr-Ti-Mn-V-Ni hydrogen Storage Alloy for Ni-MH Rechargeable Battery

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Myung; Jung, Jae Han; Lee, Sang Min; Lee, Jae Young [Department of Meterial Science and Engineering, Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1996-12-15

    The Zr-based AB{sub 5} type Laves phase hydrogen storage alloys have some promising properties, long cycle life, high discharge capacity, as electrode materials in reversible metal hydride batteries. However, when these alloys are used as negative electrode for battery, there is a problem that their rate capabilities are worse than those of commercialized AB{sub 5} type hydrogen storage alloys. In this work, we tried to develop the Zr-based AB type Laves phase hydrogen storage alloys which have high capacity and, especially, high rate capability (author). 21 refs., 2 tabs., 13 figs.

  20. On the hydrogen saturation of titanium alloys during heating billets for plastic working in gas-fired flame furnaces

    International Nuclear Information System (INIS)

    Kushakevich, S.A.; Romanova, L.A.; Bullo, P.M.

    1978-01-01

    Presented are the results of comparative investigations into titanium alloy hydridation during billet heating in gasflame and electric furnaces for forging and hot stamping. It is shown, that titanium alloys are slightly saturated with hydrogen at the temperature lower than that of polymorphic transformation. Hydrogen absorption is decelerated by a dense scale up to the moment of its loosening and peeling off. The application of protective vitreous enamels reduces the danger of impermissible hydridation. It is established, that the usage of gas-flame furnaces for billet heating is possible in the case of corresponding temperature and holding restrictions proper machining allowances and the use of protective coatings

  1. Influence of hydrogen on the thermoelectric power of palladium alloyed with neighbouring elements: I. Pd/Ru/H and Pd/Rh/H alloys

    CERN Document Server

    Szafranski, A W

    2003-01-01

    Pd/Ru and Pd/Rh alloys have been loaded with hydrogen in high-pressure conditions. The resulting hydrogen contents were close to the stoichiometric composition, H/(Pd + Me) = 1. Lower hydrogen contents have been obtained by successive partial desorptions. The thermoelectric power and electrical resistance of one- and two-phase alloys have been measured simultaneously in the temperature range between 80 and 300 K. A Nordheim-Gorter type correlation of the two quantities has been observed in many cases and the partial thermopowers corresponding to electron-phonon scattering and lattice disorder could be determined. The observed anomalous behaviour of the total and partial thermopowers is attributed to virtual bound states of ruthenium or rhodium.

  2. Low cost AB{sub 5}-type hydrogen storage alloys for a nickel-metal hydride battery

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Lijun [General Res. Inst. for Non-Ferrous Metals, Beijing (China); Zhan Feng [General Res. Inst. for Non-Ferrous Metals, Beijing (China); Bao Deyou [General Res. Inst. for Non-Ferrous Metals, Beijing (China); Qing Guangrong [General Res. Inst. for Non-Ferrous Metals, Beijing (China); Li Yaoquan [General Res. Inst. for Non-Ferrous Metals, Beijing (China); Wei Xiuying [General Res. Inst. for Non-Ferrous Metals, Beijing (China)

    1995-12-15

    The studies have been carried out on utilizing Ml(NiAl){sub 5}-based alloys as a low cost negative battery electrode. The replacement of nickel by copper improved the cycle lifetime to some extent without a decrease in capacity. Using Ml(NiAlCu){sub 5} alloys, hydrogen storage alloys with good overall characteristics and low cost were obtained through substituting cobalt or silicon for nickel. The discharge capacity was further increased by increasing the lanthanum content in lanthanum-rich mischmetal. (orig.)

  3. Grain boundary selective oxidation and intergranular stress corrosion crack growth of high-purity nickel binary alloys in high-temperature hydrogenated water

    Energy Technology Data Exchange (ETDEWEB)

    Bruemmer, S. M.; Olszta, M. J.; Toloczko, M. B.; Schreiber, D. K.

    2018-02-01

    The effects of alloying elements in Ni-5at%X binary alloys on intergranular (IG) corrosion and stress corrosion cracking (SCC) have been assessed in 300-360°C hydrogenated water at the Ni/NiO stability line. Alloys with Cr or Al additions exhibited grain boundary oxidation and IGSCC, while localized degradation was not observed for pure Ni, Ni-Cu or Ni-Fe alloys. Environment-enhanced crack growth was determined by comparing the response in water and N2 gas. Results demonstrate that selective grain boundary oxidation of Cr and Al promoted IGSCC of these Ni alloys in hydrogenated water.

  4. The Integration of a Structural Water Gas Shift Catalyst with a Vanadium Alloy Hydrogen Transport Device

    Energy Technology Data Exchange (ETDEWEB)

    Barton, Thomas; Argyle, Morris; Popa, Tiberiu

    2009-06-30

    This project is in response to a requirement for a system that combines water gas shift technology with separation technology for coal derived synthesis gas. The justification of such a system would be improved efficiency for the overall hydrogen production. By removing hydrogen from the synthesis gas stream, the water gas shift equilibrium would force more carbon monoxide to carbon dioxide and maximize the total hydrogen produced. Additional benefit would derive from the reduction in capital cost of plant by the removal of one step in the process by integrating water gas shift with the membrane separation device. The answer turns out to be that the integration of hydrogen separation and water gas shift catalysis is possible and desirable. There are no significant roadblocks to that combination of technologies. The problem becomes one of design and selection of materials to optimize, or at least maximize performance of the two integrated steps. A goal of the project was to investigate the effects of alloying elements on the performance of vanadium membranes with respect to hydrogen flux and fabricability. Vanadium was chosen as a compromise between performance and cost. It is clear that the vanadium alloys for this application can be produced, but the approach is not simple and the results inconsistent. For any future contracts, large single batches of alloy would be obtained and rolled with larger facilities to produce the most consistent thin foils possible. Brazing was identified as a very likely choice for sealing the membranes to structural components. As alloying was beneficial to hydrogen transport, it became important to identify where those alloying elements might be detrimental to brazing. Cataloging positive and negative alloying effects was a significant portion of the initial project work on vanadium alloying. A water gas shift catalyst with ceramic like structural characteristics was the second large goal of the project. Alumina was added as a

  5. Embrittlement of the alloy U 7.5 Nb 2.5 Zr by gaseous oxygen and hydrogen

    International Nuclear Information System (INIS)

    Lepoutre, D.; Nomine, A.M.; Miannay, D.

    1981-04-01

    Embrittlement of the alloy uranium 7.5 niobium 2.5 zirconium in gaseous oxygen and hydrogen versus stress intensity, temperature and pressure is studied using rupture mechanics. Cracking speed is determined. In oxygen, only cracks are produced and embrittlement is due to oxidation. In hydrogen at high pressure an hydride is formed and at low pressure cracks are produced but the mechanism is not identified [fr

  6. Fiscal 2000 report on the Phase II R and D of the international hydrogen utilization clean energy network system technology (WE-NET). Task 11. Distributed transportation of hydrogen/hydrogen absorbing alloy for hydrogen storage; 2000 nendo suiso riyo kokusai clean energy system gijutsu (WE-NET) dai 2 ki kenkyu kaihatsu seika hokokusho. 11. Suiso bunsan yuso chozoyo suiso kyuzo gokin

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    Studies were conducted to find out hydrogen absorbing alloys with an effective hydrogen absorption rate of 3 mass % or more, hydrogen discharge temperature of 100 degrees C or lower, hydrogen absorbing capacity after 5,000 cycles not less than 90% of the initial capacity, applicable to stationary and mobile systems. The V-based alloy that achieved an effective hydrogen absorption rate of 2.6 mass % in the preceding fiscal year was subjected to studies relating to safety and durability. Since V is costly, efforts were exerted to develop TiCrMo alloys to replace the V-based alloy. In the search for novel high-performance alloys, endeavors centered on novel ternary alloys, novel alloys based on Mg and Ti, and novel intermetallic compounds of the Mg-4 family. In the study of guidelines for developing next-generation high-performance alloys, methods for creating hydrides with an H/M (hydrogen/metal) ratio far higher than 2 were discussed. Mentioned as techniques to produce such hydrides were the utilization of the hole regulated lattice, novel alloys based on the ultrahigh pressure hydride phase, new substances making use of the cooperative phenomenon in the coexistent multiple-phase structure, and the like. (NEDO)

  7. Effect of hydrogen bond formation/replacement on solubility characteristics, gastric permeation and pharmacokinetics of curcumin by application of powder solution technology

    Directory of Open Access Journals (Sweden)

    Vijay Sharma

    2016-10-01

    Full Text Available The present research aimed to improve the dissolution rate and bioavailability of curcumin using the potential of liquisolid technology. Twelve drug-loaded liquisolid systems (LS-1 to LS-12 were prepared using different vehicles (PEG 200, PEG 400 and Tween 80 and curcumin concentrations in vehicle (40%, 50%, 60% and 70%, w/w. The carrier [microcrystalline cellulose (MCC PH102] to coat (Aerosil® ratio was 20 in all formulations. The systems were screened for pre-compression properties before being compressed to liquisolid tablets (LT-1 to LT-12. Post compression tests and in vitro dissolution of LTs were conducted and the results compared with those obtained for a directly compressed tablet (DCT made of curcumin, MCC PH102 and Aerosil®. LTs exhibited higher cumulative drug release (CDR than the DCT and the optimum formulation, LT-9 (made using Tween 80, was studied by powder XRD, DSC, SEM and FTIR. Ex-vivo permeation of curcumin from LT-9 through goat gastrointestinal mucosa was significantly (P<0.05 enhanced and its oral bioavailability was increased 18.6-fold in New Zealand rabbits. In vitro cytotoxicity (IC50 of LT-9 towards NCL 87 cancer cells was 40.2 µmol/L substantiating its anticancer efficacy. Accelerated stability studies revealed insignificant effects of temperature and humidity on LT-9. In summary, solubility enhancement of curcumin in LTs produced significant improvements in its permeation and bioavailability.

  8. Survey report on energy transportation systems which use hydrogen-occluding alloys; Suiso kyuzo gokin wo riyoshita energy yuso system chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1992-03-18

    Surveyed are systems which use hydrogen-occluding alloys for, e.g., storing and transporting hydrogen. This project is aimed at development of, and extraction of technical problems involved in, the concept of hydrogen energy transportation cycles for producing hydrogen in overseas countries by electrolysis using clean energy of hydraulic energy which are relatively cheap there; transporting hydrogen stored in a hydrogen-occluding alloy by sea to Japan; and converting it into electrical power to be delivered and used there. The surveyed items include current state of development/utilization of hydraulic power resources in overseas countries; pigeonholing the technical issues involved in the hydrogen transportation cycles, detailed studies thereon, and selection of the transportation cycles; current state of research, development and application of hydrogen-occluding alloys for various purposes; extraction of the elementary techniques for the techniques and systems for the hydrogen transportation systems which use hydrogen-occluding alloys; research themes of the future hydrogen-occluding alloys and the application techniques therefor, and research and development thereof; and legislative measures and safety. (NEDO)

  9. Susceptibility of cold-worked zirconium-2.5 wt% niobium alloy to delayed hydrogen cracking

    International Nuclear Information System (INIS)

    Coleman, C.E.

    1976-01-01

    Notched tensile specimens of cold-worked zirconium-2.5 wt% niobium alloy have been stressed at 350 K and 520 K. At 350 K, above a possible threshold stress of 200 MPa, specimens exhibited delayed failure which was attributed to hydride cracking. Metallography showed that hydrides accumulated at notches and tips of growing cracks. The time to failure appeared to be independent of hydrogen content over the range 7 to 100 ppm hydrogen. Crack growth rates of about 10 -10 m/s deduced from fractography were in the same range as those necessary to fracture pressure tubes. The asymptotic stress intensity for delayed failure, Ksub(1H), appeared to be about 5 MPa√m. With this low value of Ksub(1H) small surface flaws may propagate in pressure tubes which contain large residual stresses. Stress relieving and modified rolling procedures will reduce the residual stresses to such an extent that only flaws 12% of the wall thickness or greater will grow. At 520 K no failures were observed at times a factor of three greater than times to failure at 350 K. Zirconium-2.5 wt% niobium appears to be safe from delayed hydrogen cracking at the reactor operating temperature. (author)

  10. CO impurities effect on LaNi4∙7Al0∙3 hydrogen storage alloy ...

    Indian Academy of Sciences (India)

    Administrator

    LaNi4∙7Al0∙3 alloy was prepared by vacuum induction melting in high purity helium atmosphere, .... The particle size of the ... tated Ni, and hydrogen molecules are dissociated into .... range of 30–150 °C, the sample weight loss is about 1∙3%.

  11. Analysis of hydrogen distribution on Mg-Ni alloy surface by scanning electron-stimulated desorption ion microscope (SESDIM)

    International Nuclear Information System (INIS)

    Yamaga, Atsushi; Hibino, Kiyohide; Suzuki, Masanori; Yamada, Masaaki; Tanaka, Kazuhide; Ueda, Kazuyuki

    2008-01-01

    Hydrogen distribution and behavior on a Mg-Ni alloy surface are studied by using a time-of-flight electron-stimulated desorption (TOF-ESD) microscopy and a scanning electron microscope with energy dispersive X-ray spectroscopy (SEM-EDX). The desorbed hydrogen ions are energy-discriminated and distinguished into two characters in the adsorbed states, which belong to Mg 2 Ni grains and the other to oxygen-contaminated Mg phase at the grain boundaries. Adsorbed hydrogen is found to be stable up to 150 deg. C, but becomes thermally unstable around at 200 deg. C

  12. Hydrogen degradation of the 26H2MF alloy steel in H2SO4 and hydrocarbon environments

    International Nuclear Information System (INIS)

    Zielinski, A.; Swieczko-Zurek, B.; Michaliak, P.

    2004-01-01

    The Polish 26H2M alloy steel has been subjected to different heat treatment resulting in different microstructure and fracture appearance. The slow strain rate tests have been made on smooth round specimens in diluted sulphuric acid, boiler fuel and used mineral machine oil. The 26H2MF steel has become relatively immune in neutral boiler fuel and mineral oil and been heavily suffered from hydrogen degradation in acidic environment. The results demonstrate that the 26H2MF steel is highly susceptible to hydrogen degradation but in absence of stress raisers the increased hydrogen absorption in hydrocarbons can cause only small loss of its plasticity. (author) >>>

  13. Degradation of the Mechanical Properties of Zirconium-base alloys due to Interaction with Hydrogen

    International Nuclear Information System (INIS)

    Bertolino, Graciela

    2001-01-01

    Security aspects and the purpose to extend the nuclear power plants lifetime motivate the renovated interest on the influence of the environment and radiation on the mechanical properties of in-reactor materials.Zirconium based alloys are the family of alloys most extensively used in nuclear core components.A consequence of the interaction of the in-reactor environment with these alloys is the formation of brittle phase Zr hydride, a process that greatly affects the component integrity.In this work we present a experimental study of the hydrogen influence on the Z ry-4 mechanical properties at different temperatures.As a complement we also present results of a finite elements simulations of the fracture process.We performed standard metallurgical and mechanical characterization in commercial Z ry-4 samples to obtain their basic properties. Different hydrogen pickup techniques were applied to obtain H concentration of charged samples between 10 and 2000 ppm, homogeneous or mainly localized at the crack tip zone.To obtain the fracture toughness of the alloys specimens were tested using elastoplastic fracture mechanics techniques.Specifically we implement J-integral methodology with partial unloading compliance measurements.Tests were performed in a temperature range of 20 to 200 o C.The negative influence of the H content on material toughness probed to be important even at very small concentrations, with an effect that decreases when temperature increases.While there was observed no change in the fracture mechanism in homogeneous charged samples, specimens charged under a superimposed stress field fractured by brittle mode when were tested at 20 to 70 o C. SEM observations of the crack growth, the fracture surface morphology and precipitates content showed the influence of the precipitates on fracture at different H concentrations.At least three stages with different fracture behavior depending on H content were identified.Complementary to the experimental work we

  14. Hydrogen transfer in Pb–Li forced convection flow with permeable wall

    Energy Technology Data Exchange (ETDEWEB)

    Fukada, Satoshi, E-mail: sfukada@nucl.kyushu-u.ac.jp; Muneoka, Taiki; Kinjyo, Mao; Yoshimura, Rhosuke; Katayama, Kazunari

    2015-10-15

    Highlights: • The paper presents experimental and analytical results of Pb–Li eutectic alloy forced convection flow. • Analytical results are in good agreement with ones of hydrogen permeation in Pb–Li forced convection flow. • The results are useful for the design of liquid blanket of fusion reactors. - Abstract: Transient- or steady-state hydrogen permeation from a primary fluid of Li{sub 17}Pb{sub 83} (Pb–Li) through a permeable tube of Inconel-625 alloy to a secondary Ar purge is investigated experimentally under a forced convection flow in a dual cylindrical tube system. Results of the overall hydrogen permeation flux are correlated in terms of diffusivity, solubility and an average axial velocity of Pb–Li and diffusivity and solubility of the solid wall. Analytical solutions under proper assumptions are derived to simulate the transient- and steady-state rates of the overall hydrogen permeation, and close agreement is obtained between experiment and analysis. Two things are clarified from the comparison: (i) how the steady-state permeation rate is affected by the mass-transfer properties and the average velocity of Pb–Li and the properties of Inconel-625, and (ii) how its transient behavior is done by the diffusivity of the two materials. The results obtained here will give important information to estimate or to analyze the tritium transfer rate in fluidized Pb–Li blankets of DEMO or the future commercial fusion reactors.

  15. Research and development in second term of hydrogen utilizing international clean energy system technology (WE-NET) in fiscal 1999. Task 2. Hydrogen absorbing alloys for discrete hydrogen transportation and storage; 1999 nendo suiso riyo kokusai clean energy system gijutsu (WE-NET) dainiki kenkyu kaihatsu. Task 11. Suiso bunsan yuso chozoyo suiso kyuzo gokin

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    Developmental researches have been performed on hydrogen absorbing alloys intended to be applied to stationary and moving objects. This paper summarizes the achievements in fiscal 1999. As a method for evaluating effective hydrogen absorption amount, proposals were made on definition and measuring method for effective hydrogen absorption amount assuming hydrogen absorption at 20 degrees C, and 10 and 30 atmospheric pressures, and hydrogen discharge at 100 degrees C and one atmospheric pressure. In the research of an Mg-Ni based alloy, the Mg based alloy having the Laves composition, treated by mechanical grinding was found to discharge hydrogen of 0.2 to 0.35% by mass at 423K. This discharge temperature is the lowest among the Mg based alloys having been developed to date. In the research of the V based hydrogen absorbing alloy, the V-Ti-Cr-Mn alloy was developed successfully that discharges hydrogen of 2.64% by mass when hydrogen absorbed at 273 K and 3.3 MPa is discharged at 373 K and 0.01 MPa. Furthermore, development has been made on the V-Ti-Cr-Mn-Ni alloy that shows high effective hydrogen absorption amount without being treated by heat. This alloy has as high effective hydrogen absorption amount as 2.47% by mass under the above described conditions. (NEDO)

  16. Effects of Nd-addition on the structural, hydrogen storage, and electrochemical properties of C14 metal hydride alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wong, D.F. [BASF/Battery Materials-Ovonic, 2983 Waterview Drive, Rochester Hills, MI 48309 (United States); Department of Chemical Engineering, Wayne State University, Detroit, MI 48202 (United States); Young, K., E-mail: kwo.young@basf.com [BASF/Battery Materials-Ovonic, 2983 Waterview Drive, Rochester Hills, MI 48309 (United States); Department of Chemical Engineering, Wayne State University, Detroit, MI 48202 (United States); Nei, J.; Wang, L. [BASF/Battery Materials-Ovonic, 2983 Waterview Drive, Rochester Hills, MI 48309 (United States); Ng, K.Y.S. [Department of Chemical Engineering, Wayne State University, Detroit, MI 48202 (United States)

    2015-10-25

    Nd-addition to the AB{sub 2}-based alloy Ti{sub 12}Zr{sub 22.8−x}V{sub 10}Cr{sub 7.5}Mn{sub 8.1}Co{sub 7.0}Ni{sub 32.2}Al{sub 0.4}Nd{sub x} is studied for its effects on the structure, gaseous-phase hydrogen storage, and electrochemical properties. This study follows a series of Cu, Mo, Fe, Y, Si, and La doping studies in similar AB{sub 2}-based alloys. Limited solubility of Nd in the main Laves phase promotes the formation of secondary phases (AB and Zr{sub 7}Ni{sub 10}) to provide catalytic effects and synergies for improved capacity and high-rate dischargeability (HRD) performance. The main C14 storage phase has smaller lattice constants and cell volumes, and these effects reduce the storage capacity at higher Nd levels. Different hydrogen absorption mechanisms can occur in these multi-component, multi-phase alloys depending on the interfaces of the phases, and they have effects on the alloy properties. Higher Nd-levels improve the HRD performance despite having lower bulk diffusion and surface exchange current. Magnetic susceptibility measurements indicate large percentage of larger metallic nickel clusters are present in the surface oxide of alloys with higher Nd-content, and AC impedance studies show very low charge-transfer resistance with high catalytic capability in the alloys. The −40 °C charge-transfer resistance of 8.9 Ω g in this Nd-series of alloys is the lowest measured out of the studies investigating doped AB{sub 2}-based MH alloys for improved low-temperature characteristics. The improvement in HRD and low-temperature performance appears to be related to the proportion of the highly catalytic NdNi-phase at the surface, which must offset the increased bulk diffusion resistance in the alloy. - Graphical abstract: Schematics of hydrogen flow and corresponding PCT isotherms in funneling mode. - Highlights: • Structural and hydrogen storage properties of Nd-substituted AB{sub 2} metal hydride are reported. • Nd contributes to the lowest

  17. Role of vanadium carbide traps in reducing the hydrogen embrittlement susceptibility of high strength alloy steels. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, G.L.; Duquette, D.J.

    1998-08-01

    High strength alloy steels typically used for gun steel were investigated to determine their susceptibility to hydrogen embrittlement. Although AISI grade 4340 was quite susceptible to hydrogen embrittlement, ASTM A723 steel, which has identical mechanical properties but slightly different chemistries, was not susceptible to hydrogen embrittlement when exposed to the same conditions. The degree of embrittlement was determined by conducting notched tensile testing on uncharged and cathodically charged specimens. Chemical composition was modified to isolate the effect of alloying elements on hydrogen embrittlement susceptibility. Two steels-Modified A723 (C increased from 0.32% to 0.40%) and Modified 4340 (V increased from 0 to O.12%) were tested. X-ray diffraction identified the presence of vanadium carbide, V{sub 4}C{sub 3}, in A-23 steels, and subsequent hydrogen extraction studies evaluated the trapping effect of vanadium carbide. Based on these tests, it was determined that adding vanadium carbide to 4340 significantly decreased hydrogen embrittlement susceptibility because vanadium carbide traps ties up diffusible hydrogen. The effectiveness of these traps is examined and discussed in this paper.

  18. Design and qualification of an on-line permeator for the recovery of tritium from lead-lithium eutectic breeding alloy

    International Nuclear Information System (INIS)

    Veredas, G.; Fradera, J.; Fernandez, I.; Batet, L.; Penalva, I.; Mesquida, L.; Abella, J.; Sempere, J.; Martinez, I.; Herrazti, B.; Sedano, L.

    2011-01-01

    The fast and efficient recovery of bred tritium represents a major milestone of tritium breeding technologies R and D and is key for the demonstration of fusion reactor fuel self-sufficiency. For lead-lithium eutectic, diverse technologies are currently being investigated and qualified. Permeator Against Vacuum (PAV) solution represents a firm candidate because: (i) runs as a single-step process for tritium on-line recovery, (ii) works passively allowing to be thermally governed, (iii) can be easily in-pipe integrated in Pb15.7Li loop systems and (iv) can be conceived with high compactness. An optimal design of a PAV requires a detailed hydraulic design optimization for established operational ranges. An optimal PAV design is proposed and qualified by numerical simulation.

  19. TEM studies of nanostructure in melt-spun Mg-Ni-La alloy manifesting enhanced hydrogen desorbing kinetics

    International Nuclear Information System (INIS)

    Tanaka, K.; Miwa, T.; Sasaki, K.; Kuroda, K.

    2009-01-01

    The hydrogen storage properties of a magnesium-rich Mg-Ni-La alloy prepared by melt-spinning are significantly improved by nanostructure formation during crystallization and activation. It can absorb and desorb ∼5 wt% hydrogen at temperatures as low as 200 deg. C in moderate time periods. Transmission electron microscopic (TEM) studies on this alloy indicate that the nanostructure, consisting of LaH 3 and Mg 2 NiH 4 nano-particles dispersed homogeneously in MgH 2 matrices after hydrogenation, is rather stable at temperatures below 300 deg. C but undergoes coarsening and segregation of these particles and matrices above ∼400 deg. C. These structural changes have been confirmed by electron energy-loss spectroscopic (EELS) imaging as well as high-resolution TEM techniques. A new EELS peak associated with a plasmon excitation in the MgH 2 phase (H-plasmon) is found for the first time in this study. By imaging the H-plasmon peak, the hydrogen distribution in the alloy has been clearly visualized. We have succeeded in observing the hydrogen desorption process at ∼400 deg. C in-situ in the microscope using this EELS imaging technique.

  20. Hydrogen induced dis-proportionation studies on Zr-Co-M (M=Ni, Fe, Ti) ternary alloys

    International Nuclear Information System (INIS)

    Jat, Ram Avtar; Pati, Subhasis; Parida, S.C.; Agarwal, Renu; Mukerjee, S.K.; Sastry, P.U.; Jayakrishnan, V.B.

    2016-01-01

    The intermetallic compound ZrCo is considered as a suitable material for storage, supply and recovery of hydrogen isotopes in International Thermonuclear Experimental Reactor (ITER). However, upon repeated hydriding-dehydriding cycles, the hydrogen storage capacity of ZrCo decreases, which is attributed to the disproportionate reaction ZrCo + H 2 ↔ ZrH 2 + ZrCo 2 . The reduction of hydrogen storage capacity of ZrCo is not desirable for its use in tritium facilities. In our previous studies, attempts were made to improve the durability of ZrCo against dis-proportionation by including a third element. The present study is aimed to investigate the hydrogen induced dis-proportionation of Zr-Co-M (M=Ni, Fe and Ti) ternary alloys under hydrogen delivery conditions

  1. Effect of hydrogenation pressure on microstructure and mechanical properties of Ti-13Nb-13Zr alloy produced by powder metallurgy

    International Nuclear Information System (INIS)

    Duvaizem, Jose Helio; Galdino, Gabriel Souza; Bressiani, Ana Helena; Faria Junior, Rubens Nunes de; Takiishi, Hidetoshi

    2009-01-01

    The effects of the hydrogenation stage on microstructure and mechanical properties of Ti-13Nb-13Zr alloy produced by powder metallurgy have been studied. Powder alloys have been produced by hydrogenation with 250 MPa or 1 GPa and via high energy planetary ball milling. Samples were isostatically pressed at 200 MPa and sintered at 1150 deg C for 7, 10 and 13 hours. Elastic modulus and microhardness were determined using a dynamic mechanical analyzer (DMA) and a Vickers microhardness tester. Density of the samples was measured using a liquid displacement system. Microstructure and phases presents were analyzed employing scanning electron microscopy (SEM). Elastic modulus were 81.3 ± 0.8 and 62.6 ± 0.6 GPa for samples produced by 250 MPa and 1 GPa hydrogenation, respectively when sintered for 7h. (author)

  2. Healing behavior of preexisting hydrogen micropores in aluminum alloys during plastic deformation

    International Nuclear Information System (INIS)

    Toda, H.; Minami, K.; Koyama, K.; Ichitani, K.; Kobayashi, M.; Uesugi, K.; Suzuki, Y.

    2009-01-01

    Synchrotron X-ray microtomography was used to observe the shrinkage and annihilation behaviors of hydrogen micropores in three dimensions during hot and cold plastic deformation of an Al-Mg alloy. Whether complete healing of micropores is achieved after plastic deformation was examined by exposing the material to a high temperature after plastic deformation. Although micropores generally show a pattern of shrinking and closing, closer inspection of a single specimen revealed a variety of geometrically variable behaviors. It is noteworthy that some of the micropores are reinitiated in positions identical to those before their annihilation, even after an 8-22% macroscopic strain has been further applied after annihilation. We attribute local variations such as these to significant local strain variation, which we measured in a series of tomographic volumes by tracking the microstructural features.

  3. Impedance and hydrogen evolution studies on magnesium alloy in oxalic acid solution containing different anions

    Energy Technology Data Exchange (ETDEWEB)

    Fekry, A.M. [Chemistry Department, Faculty of Science, Cairo University, Giza 12613 (Egypt)

    2010-12-15

    The corrosion behavior of AZ31E alloy was investigated in oxalic acid solution using different electrochemical techniques. The effect of concentration was studied, where the corrosion rate was found to increase with increasing oxalic acid concentration and hydrogen evolution. The effect of adding Cl{sup -}, F{sup -} or PO{sub 4}{sup 3-} ions on the electrochemical behavior of AZ31E electrode was studied in 0.01 M oxalic acid solution at 298 K. It was found that the corrosion rate increases with increasing Cl{sup -} or F{sup -} ion concentration, however, it decreases with increasing PO{sub 4}{sup 3-} ion concentration. Good agreement was observed between the results obtained from electrochemical techniques and confirmed by Scanning electron micrographs. (author)

  4. Effect of Annealing on Microstructures and Hardening of Helium-Hydrogen-Implanted Sequentially Vanadium Alloys

    Science.gov (United States)

    Jiang, Shaoning; Wang, Zhiming

    2018-03-01

    The effect of post-irradiation annealing on the microstructures and mechanical properties of V-4Cr-4Ti alloys was studied. Helium-hydrogen-irradiated sequentially V-4Cr-4Ti alloys at room temperature (RT) were undergone post-irradiation annealing at 450 °C over periods of up to 30 h. These samples were carried out by high-resolution transmission electron microscopy (HRTEM) observation and nanoindentation test. With the holding time, large amounts of point defects produced during irradiation at RT accumulated into large dislocation loops and then dislocation nets which promoted the irradiation hardening. Meanwhile, bubbles appeared. As annealing time extended, these bubbles grew up and merged, and finally broke up. In the process, the size of bubbles increased and the number density decreased. Microstructural changes due to post-irradiation annealing corresponded to the change of hardening. Dislocations and bubbles are co-contributed to irradiation hardening. With the holding time up to 30 h, the recovery of hardening is not obvious. The phenomenon was discussed by dispersed barrier hardening model and Friedel-Kroupa-Hirsch relationship.

  5. Aspects of the practical application of titanium alloys after low temperature nitriding glow discharge in hydrogen- free -gas media

    Energy Technology Data Exchange (ETDEWEB)

    Mashovets, N.S., E-mail: mashovets@rambler.ru [Khmelnickiy National University (Ukraine); Pastukh, I.M., E-mail: pastim@mail.ru [Khmelnickiy National University (Ukraine); Voloshko, S.M. [Khmelnickiy National University (Ukraine); National Technical University of Ukraine “Kyiv Polytechnic Institute” (Ukraine)

    2017-01-15

    Highlights: • Surface modification of titanium alloys were carried out by low-temperature nitriding in a glow discharge in hydrogen-free environment. • Research into the phase composition was performed by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). • The above material shows the promise of the technology of low-temperature hydrogen-nitriding by glow discharge. This greatly expands the range of practical applications of titanium alloys. - Abstract: X-ray diffraction analysis, X-ray photoelectron spectroscopy, and Electron Auger-spectroscopy investigation of phase transformation on the surface of the VT8 titanium alloy after a low temperature hydrogen-free nitriding in a glow discharge. Operational characteristics of titanium alloys defined physical-mechanical characteristics of the surface and their phase composition, which depend on the process parameters of nitriding. Surface modification of titanium alloys were carried out by low-temperature nitriding in a glow discharge in hydrogen-free environment. The main advantage of this method lies in the absence of hydrogen embrittlement and complete environmental safety process. Application of the glow discharge can not only speed up the process by the order of the diffusion surface saturation with nitrogen, but also significantly alters the kinetics of the process and quality of the nitrided layer, in particular its physio-mechanical properties and phase composition. For research purposes, the standards from an α + β alloy Ti-Al6-Cr2-Mo2,5 (VT8) were used. Research into the phase composition was performed by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Stratified analysis by AES was conducted by etching the surface of the samples’ argon ion beam with diameters of 1.5 mm with an energy of 3000 eV and a current density of 400 mA/cm{sup 2}. The above material shows the promise of the technology of low

  6. Aspects of the practical application of titanium alloys after low temperature nitriding glow discharge in hydrogen- free -gas media

    International Nuclear Information System (INIS)

    Mashovets, N.S.; Pastukh, I.M.; Voloshko, S.M.

    2017-01-01

    Highlights: • Surface modification of titanium alloys were carried out by low-temperature nitriding in a glow discharge in hydrogen-free environment. • Research into the phase composition was performed by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). • The above material shows the promise of the technology of low-temperature hydrogen-nitriding by glow discharge. This greatly expands the range of practical applications of titanium alloys. - Abstract: X-ray diffraction analysis, X-ray photoelectron spectroscopy, and Electron Auger-spectroscopy investigation of phase transformation on the surface of the VT8 titanium alloy after a low temperature hydrogen-free nitriding in a glow discharge. Operational characteristics of titanium alloys defined physical-mechanical characteristics of the surface and their phase composition, which depend on the process parameters of nitriding. Surface modification of titanium alloys were carried out by low-temperature nitriding in a glow discharge in hydrogen-free environment. The main advantage of this method lies in the absence of hydrogen embrittlement and complete environmental safety process. Application of the glow discharge can not only speed up the process by the order of the diffusion surface saturation with nitrogen, but also significantly alters the kinetics of the process and quality of the nitrided layer, in particular its physio-mechanical properties and phase composition. For research purposes, the standards from an α + β alloy Ti-Al6-Cr2-Mo2,5 (VT8) were used. Research into the phase composition was performed by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Stratified analysis by AES was conducted by etching the surface of the samples’ argon ion beam with diameters of 1.5 mm with an energy of 3000 eV and a current density of 400 mA/cm 2 . The above material shows the promise of the technology of low

  7. Thermodynamical study of the vanadium-hydrogen system. The hydrogen effect on the mechanical properties of V-4Cr-4Ti and V-5Cr-5Ti alloys; Etude thermodynamique du systeme vanadium-hydrogene. Effets de l'hydrogene sur les proprietes mecaniques des alliages V-4Cr-4Ti et V-5Cr-5Ti

    Energy Technology Data Exchange (ETDEWEB)

    Coulombeaux, O

    1998-07-01

    In the framework of the international research programs on fusion reactors, the vanadium alloys are among the most appropriate candidate to constitute the first wall. The author deals with the specific alloys V-4Cr-4Ti and V-5Cr-5Ti and study the hydrogen diffusion. Experimental results show that the induced hydrogen concentration in the sample by diffusion is higher, for the same partial pressure of exposure, in the case of the alloy than for the pure vanadium. He shows that this result can be explainedby the trapping for which the hydrogen is trapped by the titanium. (A.L.B.)

  8. Permeation through graphene ripples

    Science.gov (United States)

    Liang, Tao; He, Guangyu; Wu, Xu; Ren, Jindong; Guo, Hongxuan; Kong, Yuhan; Iwai, Hideo; Fujita, Daisuke; Gao, Hongjun; Guo, Haiming; Liu, Yingchun; Xu, Mingsheng

    2017-06-01

    Real graphene sheets show limited anti-permeation performance deviating from the ideally flat honeycomb carbon lattice that is impermeable to gases. Ripples in graphene are prevalent and they could significantly influence carrier transport. However, little attention has been paid to the role of ripples in the permeation properties of graphene. Here, we report that gases can permeate through graphene ripples at room temperature. The feasibility of gas permeation through graphene ripples is determined by detecting the initial oxidation sites of Cu surface covered with isolated graphene domain. Nudged elastic band (NEB) calculations demonstrate that the oxygen atom permeation occurs via the formation of C-O-C bond, in which process the energy barrier through the rippled graphene lattice is much smaller than that through a flat graphene lattice, rendering permeation through ripples more favorable. Combining with the recent advances in atoms intercalation between graphene and metal substrate for transfer-free and electrically insulated graphene, this discovery provides new perspectives regarding graphene’s limited anti-permeation performance and evokes for rational design of graphene-based encapsulation for barrier and selective gas separation applications through ripple engineering.

  9. Hydrogenation Properties of Mg-5 wt.% TiCr_10NbX (x=1,3,5) Composites by Mechanical Alloying Process

    International Nuclear Information System (INIS)

    Kim, Kyeong-Il; Hong, Tae-Whan

    2011-01-01

    Hydrogen and hydrogen energy have been recognized as clean energy sources and high energy carrier. Mg and Mg alloys are attractive hydrogen storage materials because of their lightweight and low cost materials with high hydrogen capacity (about 7.6 wt.%). However, the commercial applications of the Mg hydrides are currently hinder by its high absorption/desorption temperature, and very slow reaction kinetics. However, Ti and Ti based hydrogen storage alloys have been thought to be the third generation of alloys with a high hydrogen capacity, which makes it difficult to handle because of high reactivity. One of the most methods to develop kinetics was addition of transition metal. Therefore, Mg-Ti-Cr-Nb alloy was fabricated to add TiCrNb by hydrogen induced mechanical alloying. TiCrNb systems have included transition metals, low operating temperatures and hydrogen storage materials. As-received specimens were characterized using X-ray Diffraction analysis (XRD), Scanning Electron Microscopy (SEM) and Thermo Gravimetric analysis/Differential Scanning Calorimetry (TG/DSC). Mg-TiCr_10Nb systems were evaluated for hydrogen kinetics by Sievert’s type Pressure-Composition-Isotherm (PCI) equipment. The operating temperature range was 473, 523, 573 and 623 K.

  10. Gaseous oxygen and hydrogen embrittlements of the uranium-10 weight % molybdenum alloy

    International Nuclear Information System (INIS)

    Corcos, Jean.

    1979-07-01

    The stress corrosion of an Uranium-10 weight % Molybdenum alloy in high purity gaseous oxygen and hydrogen was studied. Tests were performed with fracture-mechanic specimens, fatigue precracked and carried out in tension with a constant sustained load. The experimental procedure enabled to determine the S.C. morphology during the test, and its kinetics. Tests in gaseous oxygen were performed with p02=0.15 MPa from 0 0 C to 100 0 C, and at 20 0 C for p02=0.15, 0.15.10 -2 and 0.15.10 -4 MPa. Two kinetic laws are proposed. Cracking is transgranular with a quasi-clivage type, and occurs on the (1 1 1) planes of the matrix. Tests in gaseous hydrogen were performed with pH2=0.15 MPa from - 50 0 C to + 135 0 C; for all the tests, even those under no exterior load, there is a failure by S.C. and macroscopic hydruration occurs. We propose a kinetic law, which may display that the hydruration phenomenon rules the S.C. propagation. We have performed the identification of the hydride, as well as the study of the precipitation. These phenomena don't occur with pH2=0.15.10 -2 MPa. The embrittlement is thought to be due to a formation-failure cycle of an hydride precipitate at the crack tip [fr

  11. Design of Hydrogen Storage Alloys/Nanoporous Metals Hybrid Electrodes for Nickel-Metal Hydride Batteries

    Science.gov (United States)

    Li, M. M.; Yang, C. C.; Wang, C. C.; Wen, Z.; Zhu, Y. F.; Zhao, M.; Li, J. C.; Zheng, W. T.; Lian, J. S.; Jiang, Q.

    2016-06-01

    Nickel metal hydride (Ni-MH) batteries have demonstrated key technology advantages for applications in new-energy vehicles, which play an important role in reducing greenhouse gas emissions and the world’s dependence on fossil fuels. However, the poor high-rate dischargeability of the negative electrode materials—hydrogen storage alloys (HSAs) limits applications of Ni-MH batteries in high-power fields due to large polarization. Here we design a hybrid electrode by integrating HSAs with a current collector of three-dimensional bicontinuous nanoporous Ni. The electrode shows enhanced high-rate dischargeability with the capacity retention rate reaching 44.6% at a discharge current density of 3000 mA g-1, which is 2.4 times that of bare HSAs (18.8%). Such a unique hybrid architecture not only enhances charge transfer between nanoporous Ni and HSAs, but also facilitates rapid diffusion of hydrogen atoms in HSAs. The developed HSAs/nanoporous metals hybrid structures exhibit great potential to be candidates as electrodes in high-performance Ni-MH batteries towards applications in new-energy vehicles.

  12. Specific features of hydrogen boiling heat transfer on the AMg-6 alloy massive heater

    International Nuclear Information System (INIS)

    Kirichenko, Yu.A.; Kozlov, S.M.; Rusanov, K.V.; Tyurina, E.G.

    1989-01-01

    Heat transfer and nucleate burns-out saturated with hydrogen at a plate heater (thickness-13 mm, diameter of heat-transferring surface - 30 mm) made of an aluminium alloy with the low value of a heat assimilation coefficient in the pressure range from 7.2x10 3 to 6x10 5 Pa is experimentally investigated. Value of start of boiling characteristics and heat transfer coefficients during nucleate burn-out, as well as the first critical densities of a heat flux and temperature heads are obtained. Existence of certain differrences of heat exchange during boiling is shown using a massive heater made of low-heat-conductive material in comparison with other cases of hydrogen boiling. Hypothesis concerning the existence of so-called mixed boiling on the heat transfer surface, which has been detected earlier only in helium boiling, as well as concerning possible reasons of stability of film boiling ficii in preburn-out region of heat duty is discussed

  13. Hydrogen storage properties of the Zintl phase alloy SrAl{sub 2} doped with TiF{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Yunfeng, E-mail: yfzhu@njut.edu.c [College of Materials Science and Engineering, Nanjing University of Technology, 5 Xinmofan Road, Nanjing 210009 (China); Zhang Wei; Liu Zhibing; Li Liquan [College of Materials Science and Engineering, Nanjing University of Technology, 5 Xinmofan Road, Nanjing 210009 (China)

    2010-03-04

    In this paper, the structural and hydrogenation characteristics of TiF{sub 3}-doped Zintl phase alloy SrAl{sub 2} were studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and hydrogenation measurements. The results show that the hydrogenation kinetics of the Zintl phase alloy SrAl{sub 2} is improved greatly after doping with TiF{sub 3}. By adjusting the doping amount and ball milling time, the optimal doping conditions were obtained. The catalytic mechanism of TiF{sub 3} for the hydrogenation of SrAl{sub 2} was also investigated. SrAl{sub 2} does not react with TiF{sub 3} during the ball milling process. However, it reacts with TiF{sub 3} to form SrAl{sub 2}H{sub 2}, SrF{sub 2}, SrAl{sub 4} and Ti during the hydrogenation process, among which Ti plays an important role in the hydrogenation kinetics of SrAl{sub 2}.

  14. Effects of composition and microstructure of Pd-Cu-Si metallic glassy alloy thin films on hydrogen absorbing properties

    International Nuclear Information System (INIS)

    Kajita, Susumu; Kohara, Shinji; Onodera, Yohei; Fukunaga, Toshiharu; Matsubara, Eiichiro

    2011-01-01

    Thin films of Pd-Cu-Si metallic glassy alloys for a hydrogen sensor were fabricated by a sputtering method. In order to find out the effect of the composition and the microstructure of them on the hydrogen absorbing property (the H 2 response), the structural parameters based on the short-range order (SRO) were measured. Additionally, the change of the structural parameters with hydrogen absorption was measured, and the correlations of the change with the H 2 response and the hydrogen induced linear expansion coefficient (LEC) were examined. The H 2 response decreased with increases in Si content and the structural parameters. These results can be explained by the positive effects of Si content and the structural parameters on the formation of a trigonal prism which is a structural unit of Pd-based amorphous alloys, and by the negative effect of the trigonal prism on absorbing hydrogen. From the observation of the elongation of the Pd-Pd atomic distance with absorbing hydrogen, H atoms are supposed to occupy the space between Pd atoms. The amount of the change in the Pd-Pd atomic distance showed the positive correlations with the H 2 response and the LEC. (author)

  15. Hydrogen storage performances of LaMg{sub 11}Ni + x wt% Ni (x = 100, 200) alloys prepared by mechanical milling

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanghuan, E-mail: zhangyh59@sina.com [Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China); Wang, Haitao [Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China); Zhai, Tingting; Yang, Tai; Yuan, Zeming; Zhao, Dongliang [Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China)

    2015-10-05

    Highlights: • Amorphous and nanostructured alloys were prepared by mechanical milling. • The maximum discharge capacity of ball milled alloys reaches to 1053.5 mA h/g. • The addition of Ni significantly increases the discharge capacity. • Increasing milling time reduces the kinetic performances of ball milled alloys. - Abstract: In order to improve the hydrogen storage performances of Mg-based materials, LaMg{sub 11}Ni alloy was prepared by vacuum induction melting. Then the nanocrystalline/amorphous LaMg{sub 11}Ni + x wt% Ni (x = 100, 200) hydrogen storage alloys were synthesized by ball milling technology. The structure characterizations of the alloys were carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical hydrogen storage characteristics were tested by using programmed control battery testing system. The electrochemical impedance spectra (EIS), potentiodynamic polarization curves and potential-step curves were also plotted by an electrochemical workstation (PARSTAT 2273). The results indicate that the as-milled alloys exhibit a nanocrystalline and amorphous structure, and the amorphization degree of the alloys visibly increases with extending milling time. Prolonging the milling duration markedly enhances the electrochemical discharge capacity and cyclic stability of the alloys. The electrochemical kinetics, including high rate discharge ability (HRD), charge transfer rate, limiting current density (I{sub L}), hydrogen diffusion coefficient (D), monotonously decrease with milling time prolonging.

  16. Achievement report for fiscal 1993. International clean energy system technology to utilize hydrogen (WE-NET) (Sub-task 5. Development of hydrogen transportation and storage technology) (Edition 5. Development of hydrogen absorbing alloys for discrete transportation and storage); 1993 nendo seika hokokusho. Suiso riyo kokusai clean energy system gijutsu (WE-NET) . Sub tusk 5. Suiso yuso chozo gijutsu no kaihatsu - Dai 5 hen. Bunsan yuso chozo you suiso kyuzo gokin no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-03-01

    Surveys and researches have been performed with an objective to accumulate knowledge required for R and D of a hydrogen transportation and storage technology. With respect to the hydrogen absorbing alloys for hydrogen transportation and storage, surveys have been carried out on the rare earth-nickel based alloy, magnesium based alloy, titanium/zirconium based alloy, vanadium based alloy, and other alloys. Regarding the hydrogen transportation and storage technology using hydrogen absorbing alloys, surveys have been made on R and D cases for hydrogen transporting containers, stationary hydrogen storing equipment, and hydrogen fuel tank for mobile equipment such as automobiles. For the R and D situation in overseas countries, site surveys have been executed on research organizations in Germany and Switzerland, the leader nations in R and D of hydrogen absorbing alloys. As a result of the surveys, the hydrogen absorbing alloys were found to have such R and D assignments as increase of effective hydrogen absorbing quantity, compliance with operating conditions, life extension, development of alloys easy in initial activation and fast in hydrogen discharge speed, and cost reduction. Items of the transportation and storage equipment have such assignments as making them compact, acceleration of heat conduction in alloy filling layers, handling of volume variation and internal stress, and long-term durability. (NEDO)

  17. Synthesis and hydrogen storage of La23Nd7.8Ti1.1Ni33.9Co32.9Al0.65 alloys

    Directory of Open Access Journals (Sweden)

    Priyanka Meena

    2018-04-01

    Full Text Available The present work investigates structural and hydrogen storage properties of first time synthesized La23Nd7.8Ti1.1Ni33.9Co32.9Al0.65 alloy by arc melting process and ball milled to get it in nano structure form. XRD analysis of as-prepared alloy showed single phased hexagonal LaNi5-type structure with 52 nm average particle size, which reduces to about 31 nm after hydrogenations. Morphological studies by SEM were undertaken to investigate the effect of hydrogenation of nanostructured alloy. EDX analysis confirmed elemental composition of the as-prepared alloy. Activation energy for hydrogen desorption was studied using TGA analysis and found to be −76.86 kJ/mol. Hydrogenation/dehydrogenation reactions and absorption kinetics were measured at temperature 100 °C. The equilibrium plateau pressure was determined to be 2 bar at 100 °C giving hydrogen storage capacity of about 2.1 wt%. Keywords: Hydrogen storage, La23Nd7.8Ti1.1Ni33.9Co32.9Al0.65 alloy, SEM, EDS, TGA, Hydrogenation/dehydrogenation

  18. Material characteristic of Ti alloy (Ti-6Al-4V)

    International Nuclear Information System (INIS)

    Toyoshima, Noboru

    1997-03-01

    In regard to material characteristic of Ti alloy (Ti-6Al-4V), the following matters are provided by experiments. 1) In high temperature permeation behavior of implanted deuterium ion (0.5keV, 6.4 x 10 18 D + ions/m 2 s, ∼760deg K), the ratio of permeation flux to incident flux ranges from 3.3 x 10 -3 at 633deg K to 4.8 x 10 -3 at 753deg K. The activation energy of permeation is 0.12eV in this temperature region above 600deg K. At temperatures below 600deg K, the permeation flux of deuterium decreases drastically and the implanted ions remain in the alloy. 2) Radioactivation analysis using 14MeV fast neutron shows that Ti-6Al-4V alloy contains higher values of principal ingredients, Al, V, Fe, than that recorded at the chemical composition of Ti alloy, and also, contains impurities with Ni, Co and Mn. 3) Fraction of about 0.095wt% H 2 were absorbed in the test specimens, and tensile strength test was carried out. Under the condition of the hydrogen pressure 50 torr and temperature ∼500degC. The results show that there is no degradation in mechanical properties for absorption of with less than 0.04wt% H 2 . The tensile strength of wilding specimens have almost the same as that without wilding. Ti alloy, as a material of vacuum vessel of nuclear fusion device, must be selected to that with less impurities, particularly Co, by radioactivation analysis, and must be used under the temperature of 200-300degC, where hydrogen absorption does not make too progress. It is considered that Ti alloy can be used with less than 0.04wt% H 2 absorption in viewpoint of material mechanical strength. (author)

  19. Hydrogen storage alloy electrode for metal-hydride alkaline storage battery its production method; Kinzoku-suisokabutsu aruakri chikudenchiyo no suiso kyuzo gokin denkyoku oyobi sono seizo hoho

    Energy Technology Data Exchange (ETDEWEB)

    Matsuura, Y.; Nogami, K.; Kimoto, M.; Higashiyama, N.; Kuroda, Y.; Yonezu, I.; Nishio, K.

    1997-03-28

    Recently, it is proposed to employ the hydrogen storage alloy produced by means of rapidly solidifying single roll method, i.e., a method of projecting the molten alloy onto the surface of roll rotating in high speed as for the negative electrode material of the metal hydride alkaline battery. However, the hydrogen storage alloy produced by the single roll method has a heterogeneous grain size. So that the utilization of the hydrogen storage alloy is limited. This invention solves the problem. The rare earth-nickel system hydrogen storage alloy ribbon with average thickness of 0.08 - 0.35 mm is produced by means of single roll method. The grain size of the alloy is over 0.2 micrometer on roll surface side and below 20 micrometers on open surface side. The above said alloy is ground to average particle size of 25 - 70 micrometers to be used for the hydrogen absorbent. In this way, the metal hydride alkaline battery with excellent high rate discharge characteristic at the initial stage of charge-discharge cycle, excellent charge-discharge cycle characteristic, and excellent inner pressure characteristic can be produced. 2 figs., 5 tabs.

  20. Tritium permeation barriers for fusion technology

    International Nuclear Information System (INIS)

    Perujo, A.; Forcey, K.

    1994-01-01

    An important issue concerning the safety, feasibility and fueling (i.e., tritium breeding ratio and recovery from the breeding blanket) of a fusion reactor is the possible tritium leakages through the structural materials and in particular through those operating at high temperatures. The control of tritium permeation could be a critical factor in determining the viability of a future fusion power reactor. The formation of tritium permeation barriers to prevent the loss of tritium to the coolant by diffusion though the structural material seems to be the most practical method to minimize such losses. Many authors have discussed the formation of permeation barriers to reduce the leakage of hydrogen isotopes through proposed first wall and structural materials. In general, there are two routes for the formation of such a barrier, namely: the growth of oxide layers (e.g., Cr 2 O 3 , Al 2 O 3 , etc.) or the application of surface coatings. Non-metals are the most promising materials from the point of view of the formation of permeation barriers. Oxides such as Al 2 O 3 or Cr 2 O 3 or carbides such as SiC or TiC have been proposed. Amongst the metals only tungsten or gold are sufficiently less permeable than steel to warrant investigation as candidate materials for permeation barriers. It is of course possible to grow oxide layers on steel directly by heating in the atmosphere or under a variety of conditions (first route above). The direct oxidizing is normally done in an environment of open-quotes wet hydrogenclose quotes to promote the growth of chromia on, for example, nickel steels or ternary oxides on 316L to prevent corrosion. The application of surface layers (second route above), offers a greater range of materials for the formation of permeation barriers. In addition to reducing permeation, such layers should be adhesive, resistant to attack by corrosive breeder materials and should not crack during thermal cycling

  1. Hydrogen storage thermodynamics and kinetics of LaMg11Ni + x wt.% Ni (x = 100, 200) alloys synthesized by mechanical milling

    International Nuclear Information System (INIS)

    Zhang, Yanghuan; Jia, Zhichao; Central Iron and Steel Research Institute, Beijing; Yuan, Zeming; Qi, Yan; Zhao, Dongliang; Hou, Zhonghui

    2016-01-01

    LaMg 11 Ni + x wt.% Ni (x = 100, 200) composite hydrogen storage alloys with a nanocrystalline/amorphous structure were synthesized using ball milling technology. The effects of Ni content and milling time on hydrogen storage thermodynamics and dynamics of the alloys were investigated systematically. The hydrogen desorption properties were assessed using a Sieverts apparatus and differential scanning calorimetry. The thermodynamic parameters for the hydrogen absorption and desorption were calculated using the Van't Hoff equation. The hydrogen desorption activation energies of the hydrogenated alloys were also estimated by Arrhenius and Kissinger methods. Results indicate that the amount of Ni added has no effect on the thermodynamics of the alloys, but it significantly improves their absorption and desorption kinetics. Furthermore, the milling time has a great influence on the hydrogen storage properties. To be specific, the hydrogen absorption capacities reach the maximum values with the variation of milling time, and the hydrogen desorption activation energy obviously decreases with increasing milling time.

  2. IGSCC growth behaviors of Alloy 690 in hydrogenated high temperature water

    Energy Technology Data Exchange (ETDEWEB)

    Arioka, K.; Yamada, T.; Miyamoto, T.; Terachi, T. [INSS, (Japan)

    2011-07-01

    The rate of growth of stress corrosion cracking (SCC) was measured for cold worked and thermally treated and solution treated Alloy 690 (UNS N06690, CW TT690, CW ST690) in hydrogenated pressurized water reactor (PWR) primary water under static load condition. Three important patterns were observed: First, Intergranular stress corrosion cracking (IGSCC) was observed on both TT and ST690 even in static load condition if materials were heavily cold worked although the rate of SCC growth was much slower than that of CW mill annealed Alloy 600. Furthermore much rapid SCC growth was recognized in 20% CW TT690 than that of 20% CW ST690. This is quite different result in the literature in high temperature caustic solution. Second, in order to assess the role of creep, rates of creep crack growth were measured in air, argon, and hydrogen gas environments using 20% CW TT690, and 20% CW MA600 in the range of temperatures between 360 and 460 C; intergranular creep cracking (IG creep cracking) was observed on the test materials even in air. Similar slope of 1/T-type temperature dependencies on IGSCC and IG creep crack growth were observed on 20% CW TT690. Similar fracture morphologies and similar 1/T-type temperature dependencies suggest that creep is important in the growth of IGSCC of CW TT690 in high temperature water. Third, cavities and pores were observed at grain boundaries near tips of SCC and creep although the size of the cavities and pores of SCC were much smaller than that of creep cracks. Also the population and size of cavities seem to decrease with decreasing test temperature. These results suggest that the difference in the size and population of cavities might be related with the difference in crack growth rate. And the cavities seem to be formed result from collapse of vacancies at grain boundaries as the crack embryo. This result suggests that diffusion of condensation of vacancies in high stressed fields occurs in high temperature water and gas environments

  3. Studies of interdiffusion and alloy formation in Fe/V multilayers using hydrogen as a local probe

    International Nuclear Information System (INIS)

    Rodmacq, B.; Stillesjoe, F.; Hjoervarsson, B.

    1993-01-01

    The thermal stability of Fe/V multilayers has been investigated for annealing temperatures in the range 423-650 K. The results show that the chemical composition profile is stable at 423 K. At higher temperatures, interdiffusion starts. No preferential alloy formation was found at the interfaces up to 650 K. The hydrogen concentration is measured with the 1 H( 15 N, αγ) 12 C-nuclear resonance reaction. 2 figs., 13 refs

  4. Interpretation of acoustic parameters obtained by EMAR measurement for non-destructive hydrogen concentration measurement in Zr alloy

    International Nuclear Information System (INIS)

    Nakatsuka, Masafumi; Uchida, Katsuya; Miyazaki, Akihiro; Ishii, Yoshiaki

    2007-01-01

    An obvious quantitative relation between hydrogen concentrations in zirconium alloy and acoustic anisotropy parameters obtained by the electromagnetic acoustic resonance (EMAR) method was reported. To elucidate the mechanism, the acoustic parameters were calculated based on the elastic theory and the equation of motion. The acoustic parameters of obtained by the EMAR method were interpreted quantitatively using the anisotropic elastic constants of the specimen, and value calculated from texture data for non-hydrogen charged specimens showed good agreement with those obtained by the EMAR method. Calculated temperature dependence of the acoustic anisotropy for the non-hydrogen charged specimen also agreed well with that by the EMAR method. The consistencies demonstrated that the absolute values of the acoustic parameters for non-hydrogen charged specimen can be calculated from both the texture data of (0002) pole figure and the elastic constants of the specimen. Hydrogen addition up to approximately 650ppm was found not to change the original (0002) pole figure and, correspondingly, no hydrogen concentration dependence of the acoustic parameters was obtained from the calculation. These results implied that the zirconium hydride itself played an important role for the change in the acoustic parameters of the hydrogen charged specimens, and the importance of obtaining the information on the elastic constants of the zirconium hydride was pointed out. (author)

  5. Structure and electrochemical hydrogen storage properties of Ti2Ni alloy synthesized by ball milling

    International Nuclear Information System (INIS)

    Hosni, B.; Li, X.; Khaldi, C.; ElKedim, O.; Lamloumi, J.

    2014-01-01

    Highlights: • The Ti 2 Ni alloy activation requires only one cycle of charge and discharge, regardless of the temperature. • By increasing the temperature the capacity loss, undergoes an increase and it is more pronounced for the 60 °C. • A good correlation is found between the evolutions of the different electrochemical parameters according to the temperature. - Abstract: The structure and the electrochemical hydrogen storage properties of amorphous Ti 2 Ni alloy synthesized by ball milling and used as an anode in nickel–metal hydride batteries were studied. Nominal Ti 2 Ni was synthesized under argon atmosphere at room temperature using a planetary high-energy ball mill. The structural and morphological characterization of the amorphous Ti 2 Ni alloy is carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical characterization of the Ti 2 Ni electrodes is carried out by the galvanostatic charging and discharging, the constant potential discharge, the open circuit potential and the potentiodynamic polarization techniques. The Ti 2 Ni alloy activation requires only one cycle of charge and discharge, regardless of the temperature. The electrochemical discharge capacity of the Ti 2 Ni alloy, during the first eight cycles, and at a temperature of 30 °C, remained practically unchanged and a good held cycling is observed. By increasing the temperature, the electrochemical discharge capacity loss after eight cycles undergoes an increase and it is more pronounced for the temperature 60 °C. At 30 °C, the anodic corrosion current density is 1 mA cm −2 and then it undergoes a rapid drop, remaining substantially constant (0.06 mA cm −2 ) in the range 40–60 °C, before undergoing a slight increase to 70 °C (0.3 mA cm −2 ). This variation is in good agreement with the maximum electrochemical discharge capacity values found for the different temperatures. By increasing the

  6. Plastic deformation and hysteresis for hydrogen storage in Pd–Rh alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cappillino, P.J., E-mail: pcappil@sandia.gov [Sandia National Laboratories, PO Box 969, Mail Stop 9292, Livermore, CA 94551 (United States); Lavernia, E.J. [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616 (United States); Ong, M.D. [Department of Physics, Whitworth University, Spokane, WA 99251 (United States); Wolfer, W.G.; Yang, N.Y. [Sandia National Laboratories, PO Box 969, Mail Stop 9292, Livermore, CA 94551 (United States)

    2014-02-15

    Highlights: • Experimental evidence of plastic work resulting from hydriding of palladium is presented. • A model of this plastic work was generated and correlated to hysteresis losses. • This hysteresis is thought to be important to the lifetime of hydrogen storage materials. • Yield strength values predicted by this model agree with measured hardness. -- Abstract: The hysteresis observed when reversibly absorbing and desorbing hydrogen in metals is currently not fully understood. In general, a hysteresis represents energy that is dissipated during a cycle, but the underlying mechanism of dissipation is still uncertain. It has been suggested that the hysteresis arises either from plastic work, or from elastic strains associated with the accommodation of the hydride phase, or from both. We present here experimental evidence that implicates plastic deformation as the cause of the hysteresis in a Pd–Rh alloy. The plastic work is evident from the increased dislocation density, from the accumulation of surface steps from slip bands, from line broadening of X-ray diffraction peaks, and from an increase in hardness with the number of hydriding cycles. A model of this plastic work is developed that depends on an effective yield strength. When this model is correlated with the measured hysteresis losses, two values are found for the effective yield strength. The lower value is shown to agree with yield strength values derived from Vickers hardness measurements. The hysteresis areas for repeated cycles of absorption and desorption decrease little with the number of cycles which is reminiscent of the plastic deformation hysteresis during low-cycle fatigue of metals. This similarity further confirms the plastic nature of the hydriding hysteresis.

  7. Microstructural evolution of Cu-1at% Ti alloy aged in a hydrogen atmosphere and its relation with the electrical conductivity

    KAUST Repository

    Semboshi, Satoshi

    2009-04-01

    Copper alloys with titanium additions between 1 and 6 at% Ti emerge currently as attractive conductive materials for electrical and electronic commercial products, since they exhibit superior mechanical and electrical properties. However, their electrical conductivity is reduced owing to the residual amount of Ti solutes in the Cu solid solution (Cu(ss)) phase. Since Cu shows only poor reactivity with hydrogen (H), while Ti exhibits high affinity to it, we were inspired by the idea that hydrogenation of Cu-Ti alloys would influence their microstructure, resulting in a significant change of their properties. In this contribution, the influence of aging under a deuterium (D(2)) atmosphere of Cu-1 at% Ti alloys on their microstructure is investigated to explore the effects on the electrical conductivity. The specimens were investigated by means of transmission electron microscopy (TEM), field ion microscopy (FIM), computer-aided field ion image tomography (cFIIT), and atom probe tomography (APT). At an early aging stage at 623 K in a D(2) atmosphere of 0.08 Wit, ellipsoidal alpha-Cu(4)Ti precipitates are formed in the alloy, and during subsequent aging, delta-TiD(2) is competitively nucleated instead of growth of alpha-Cu(4)Ti particles. The co-precipitation of alpha-Cu(4)Ti and delta-TiD(2) efficiently reduces the Ti concentration of Cuss matrix, particularly in the later aging stages in comparison to the aging in vacuum conditions. The electrical conductivity of the alloy aged in the D(2) atmosphere increases steeply up to 48% International Annealed Copper Standard (IACS) after 1030 It, while it saturates to approximately 20% IACS in the alloy aged in vacuum. The outstanding increase of electrical conductivity during aging in D2 atmosphere can be basically explained by the reduction of Ti solute concentration in Cuss matrix. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.

  8. Development of Nanoporous Ni-Sn Alloy and Application for Chemoselective Hydrogenation of Furfural to Furfuryl Alcohol

    Directory of Open Access Journals (Sweden)

    Rodiansono Rodiansono

    2014-03-01

    Full Text Available A very simple synthetic procedure was developed for the preparation of Ni-Sn alloy catalysts that were utilised for chemoselective hydrogenation of furfural, producing furfuryl alcohol almost exclusively. The mixture of nickel nanoparticles supported on aluminium hydroxide (R-Ni/AlOH and a solution containing tin was treated under hydrothermal condition, producing the as prepared nickel-tin alloy supported on aluminium hydroxide (Ni-Sn/AlOH. H2 treatment at range of temperature of 673-873 K for 1.5 h to the as prepared Ni-Sn/AlOH produced nanoporous Ni-Sn alloy catalysts. XRD patterns and SEM images revealed that the formation of Ni-Sn alloy of Ni3Sn and Ni3Sn2 phases and the transformation of crystalline gibbsite and bayerite into amorphous alumina were clearly observed after H2 treatment at 873 K. The formation of the Ni-Sn alloy may have played a key role in the enhancement of the chemoselectivity. © 2014 BCREC UNDIP. All rights reservedReceived: 1st September 2013; Revised: 26th November 2013; Accepted: 7th December 2013[How to Cite: Rodiansono, R., Hara, T., Ichikuni, N., Shimazu, S. (2014. Development of Nanoporous Ni-Sn Alloy and Application for Chemoselective Hydrogenation of Furfural to Furfuryl Alcohol. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (1: 53-59. (doi:10.9767/bcrec.9.1.5529.53-59][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.1.5529.53-59

  9. Stability of rapidly quenched and hydrogenated Mg-Ni-Y and Mg-Cu-Y alloys in extreme alkaline medium

    International Nuclear Information System (INIS)

    Gebert, A.; Khorkounov, B.; Wolff, U.; Mickel, Ch.; Uhlemann, M.; Schultz, L.

    2006-01-01

    Amorphous-nanocrystalline Mg 50 Ni 30 Y 20 and Mg 63 Ni 30 Y 7 and amorphous Mg 65 Cu 25 Y 10 alloys were produced by melt-spinning and characterized regarding their microstructure and thermal behaviour using XRD, TEM and DSC. Their electrochemical behaviour in the as-quenched state and after hydrogen charging at -25 mA/cm 2 for up to 20 h was studied in electrolytes with pH 5-7 and 13, but mainly in a battery electrolyte: 6 M KOH with pH 14.8 by means of anodic and cathodic polarization measurements. In the as-quenched state, the highest alloys stability was observed at pH 13. At pH 14.8, gradual oxidation and dissolution of copper or nickel governs the anodic behaviour before a passive state is attained. The dissolution of nickel is much more inhibited than that of copper due to its lower tendency to form soluble oxidized ions and to a stabilizing effect of higher fractions of yttrium in the alloy on the passivation. By galvanostatic charging, the Mg 65 Cu 25 Y 10 alloy shows the highest hydrogen absorption capacity followed by Mg 50 Ni 30 Y 20 and Mg 63 Ni 30 Y 7 . During the charging process, the alloys exhibit a change in the surface state chemistry, i.e. an enrichment of nickel- or copper-rich species, causing preferential oxidation and dissolution during subsequent exposure under free corrosion and anodic conditions. Mg-Ni-Y alloys demonstrate a higher stability during this treatment in extreme alkaline medium. The reasons for this and consequences regarding the use as electrode materials are discussed in detail

  10. Superaerophobic Ultrathin Ni-Mo Alloy Nanosheet Array from In Situ Topotactic Reduction for Hydrogen Evolution Reaction.

    Science.gov (United States)

    Zhang, Qian; Li, Pengsong; Zhou, Daojin; Chang, Zheng; Kuang, Yun; Sun, Xiaoming

    2017-11-01

    Hydrogen evolution reaction (HER) has prospect to becoming clean and renewable technology for hydrogen production and Ni-Mo alloy is among the best HER catalysts in alkaline electrolytes. Here, an in situ topotactic reduction method to synthesize ultrathin 2D Ni-Mo alloy nanosheets for electrocatalytic hydrogen evolution is reported. Due to its ultrathin structure and tailored composition, the as-synthesized Ni-Mo alloy shows an overpotential of 35 mV to reach a current density of 10 mA cm -2 , along with a Tafel slope of 45 mV decade -1 , demonstrating a comparable intrinsic activity to state-of-art commercial Pt/C catalyst. Besides, the vertically aligned assemble structure of the 2D NiMo nanosheets on conductive substrate makes the electrode "superaerophobic," thus leading to much faster bubble releasing during HER process and therefore shows faster mass transfer behavior at high current density as compared with drop drying Pt/C catalyst on the same substrate. Such in situ topotactic conversion finds a way to design and fabricate low-cost, earth-abundant non-noble metal based ultrathin 2D nanostructures for electrocatalytic issues. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Phase Transformation and Hydrogen Storage Properties of an La7.0Mg75.5Ni17.5 Hydrogen Storage Alloy

    Directory of Open Access Journals (Sweden)

    Lin Hu

    2017-10-01

    Full Text Available X-ray diffraction showed that an La7.0Mg75.5Ni17.5 alloy prepared via inductive melting was composed of an La2Mg17 phase, an LaMg2Ni phase, and an Mg2Ni phase. After the first hydrogen absorption/desorption process, the phases of the alloy turned into an La–H phase, an Mg phase, and an Mg2Ni phase. The enthalpy and entropy derived from the van’t Hoff equation for hydriding were −42.30 kJ·mol−1 and −69.76 J·K−1·mol−1, respectively. The hydride formed in the absorption step was less stable than MgH2 (−74.50 kJ·mol−1 and −132.3 J·K−1·mol−1 and Mg2NiH4 (−64.50 kJ·mol−1 and −123.1 J·K−1·mol−1. Differential thermal analysis showed that the initial hydrogen desorption temperature of its hydride was 531 K. Compared to Mg and Mg2Ni, La7.0Mg75.5Ni17.5 is a promising hydrogen storage material that demonstrates fast adsorption/desorption kinetics as a result of the formation of an La–H compound and the synergetic effect of multiphase.

  12. Hydrogen Storage and Release Properties of Transition Metal-Added Magnesium Hydride Alloy Fabricated by Grinding in a Hydrogen Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Sung Nam; Song, Myoung Youp [Chonbuk National University, Jeonju (Korea, Republic of); Park, Hye Ryoung [Chonnam National University, Gwangju (Korea, Republic of)

    2016-07-15

    90 wt% MgH{sub 2}+5 wt% Ni+2.5 wt% Fe+2.5 wt% Ti (called MgH{sub 2}+Ni+Fe+Ti), a hydrogen storage and release material, was fabricated by grinding in a hydrogen atmosphere, and then its quantities of stored and released hydrogen as a function of time were examined. A nanocrystalline MgH{sub 2}+Ni+Fe+Ti specimen was made by grinding in a hydrogen atmosphere and subsequent hydrogen storage-release cycling. The crystallite size of Mg and the strain of the Mg crystallite after ten hydrogen storage-release cycles, which were obtained using the Williamson-Hall method, were 38.6 (±1.4) nm and 0.025 (±0.0081) %, respectively. The MgH{sub 2}+Ni+Fe+Ti sample after the process of grinding in a hydrogen atmosphere was highly reactive with hydrogen. The sample exhibited an available storage capacity of hydrogen (the amount of hydrogen stored during 60 minutes) of about 5.7 wt%. At the first cycle, the MgH2+Ni+Fe+Ti sample stored hydrogen of 5.53 wt% in 5 minutes, 5.66 wt% in 10 minutes and 5.73 wt% in 60 minutes at 573 K and 12 bar of hydrogen. The MgH{sub 2}+Ni+Fe+Ti after activation released hydrogen of 0.56 wt% in 5 minutes, 1.26 wt% in 10 minutes, 2.64 wt% in 20 minutes, 3.82 wt% in 30 minutes, and 5.03 wt% in 60 minutes.

  13. Proton nuclear magnetic resonance studies of hydrogen diffusion and electron tunneling in Ni-Nb-Zr-H glassy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Niki, Haruo; Okuda, Hiroyuki; Oshiro, Morihito; Yogi, Mamoru [Department of Physics, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213 (Japan); Seki, Ichiro; Fukuhara, Mikio [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

    2012-06-15

    Using the Fourier transform of the echo envelope, the proton line shapes, spin-lattice relaxation time, and spin-spin relaxation time have been measured in a (Ni{sub 0.36}Nb{sub 0.24}Zr{sub 0.40}){sub 90}H{sub 10} glassy alloy at 1.83 T ({approx}78 MHz) and at temperatures between 1.8 and 300 K. First, the spectral line width decreases abruptly between 1.8 and 2.1 K. Next, it remains almost constant at 13 kHz up to {approx}150 K. Finally, the line width decreases as the temperature increases from {approx}150 to 300 K. The initial decrease in the spectral line width is ascribed to the distribution of the external field, which is caused by the penetration of vortices in the superconducting state. The subsequent leveling off in the spectral line width is ascribed to the dipole-dipole interaction between protons when hydrogen atoms are trapped into vacancies among the Zr-centered icosahedral Zr{sub 5}Ni{sub 5}Nb{sub 3} clusters. The final decrease in the spectral line width is ascribed to the motional narrowing of the width that is caused by the movement of hydrogen atoms. The temperature dependences of the spin-lattice and spin-spin relaxation time showed that at temperature above 150 K and the activation energy of 8.7 kJ/mol allowed the hydrogen atoms to migrate among the clusters. The distance between the hydrogen atoms is estimated to be 2.75 A. Hydrogen occupancies among clusters in the (Ni{sub 0.36}Nb{sub 0.24}Zr{sub 0.40}){sub 90}H{sub 10} glassy alloy play an important role in the diffusion behavior and in the electronic properties of this alloy.

  14. Influence of dissolved hydrogen on aluminum-lithium alloy fracture behavior

    Science.gov (United States)

    Rivet, F. C.; Swanson, R. E.

    1989-01-01

    The objective of this work is to study the effects of dissolved hydrogen on the mechanical properties of 2090 and 2219 alloys. Prior to mechanical testing, potentiostatic and potentiodynamic tests were performed using NaCl/HCl solutions varying in pH from 1.5 to 7.5 (3.5 pct NaCl in deionized water). After analysis of the potentiodynamic curve for each solution, several potentiostatic experiments were conducted for various times (from 10 minutes to several hours) with a cathodic overpotential of 300 mV. These experiments were performed to select charging conditions. It is shown that the fracture of L-S and T-S orientations proceeds via slipping of layers in the S-T direction. The T-S and L-S orientations fractured with substantially higher propagation energy that the L-T and T-L orientations, due in large part to the extensive delamination propagation of the fracture.

  15. Minimum Entropy Generation Theorem Investigation and Optimization of Metal Hydride Alloy Hydrogen Storage

    Directory of Open Access Journals (Sweden)

    Chi-Chang Wang

    2014-05-01

    Full Text Available The main purpose of this paper is to carry out numerical simulation of the hydrogen storage on exothermic reaction of metal hydride LaNi5 alloy container. In addition to accelerating the reaction speed of the internal metal hydride by internal control tube water-cooled mode, analyze via the application of second law of thermodynamics the principle of entropy generation. Use COMSOL Mutilphysics 4.3 a to engage in finite element method value simulation on two-dimensional axisymmetric model. Also on the premise that the internal control tube parameters the radius ri, the flow rate U meet the metal hydride saturation time, observe the reaction process of two parameters on the tank, entropy distribution and the results of the accumulated entropy. And try to find the internal tube parameter values of the minimum entropy, whose purpose is to be able to identify the reaction process and the reaction results of internal tank’s optimum energy conservation.

  16. Quantitative tomography of hydrogen precharged and uncharged Al-Zn-Mg-Cu alloy after tensile fracture

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, C., E-mail: joy_gupta71@yahoo.co.in [Department of Mechanical Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8150 (Japan); Toda, H.; Fujioka, T.; Kobayashi, M. [Department of Mechanical Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8150 (Japan); Hoshino, H. [Department of Mechanical Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8150 (Japan); Japan Synchrotron Radiation Institute, Sayo-Gun, Hyogo (Japan); Uesugi, K.; Takeuchi, A.; Suzuki, Y. [Japan Synchrotron Radiation Institute, Sayo-Gun, Hyogo (Japan)

    2016-07-18

    Quantitative tomography is carried out on datasets derived from tensile fracture sample of electrochemically precharged Al-Zn-Mg-Cu alloy in the underaged condition and its uncharged counterpart. It is shown that precharging which induces a transition of tensile fracture mode from ductile to brittle, results in a significant increase in micro-damage content in the regions near the fracture surfaces. Using quantitative tomography analysis based on spatial mapping of morphologically segmented micro-damage content of the datasets it is found that the precharged sample contains an inhomogenous distribution of micro-pores near grain boundaries. It is also shown that the spatial architecture of micro-pores in the dataset is not influenced by the plastic zone of the intergranular cracks lying along the grain boundaries. Contrastingly the micro-pores in the tomographic dataset of the uncharged sample are shown to be present near intermetallic particles. It is therefore rationalized that the spatial architecture of micro-pores in the datasets from uncharged sample originate from particle cracking during ductile fracture, and from the tendency for damage enhancement by the synergism of hydrogen exposure near grain boundaries and localization of deformation in the precharged sample dataset.

  17. Effect of soluble zinc additions on the SCC performance of nickel alloys in deaerated hydrogenated water

    International Nuclear Information System (INIS)

    Morton, D.S.; Thompson, C.D.; Gladding, D.; Schurman, M.K.

    1997-08-01

    Stress corrosion crack growth rates (SCCGR) of alloy 600, EN82H and X-750 were measured in deaerated hydrogenated water to determine if soluble zinc mitigates SCCGR. Constant load compact tension specimen tests were conducted. Two test strategies were used to discern a possible zinc effect. The first strategy employed separate SCCGR tests in zinc and non-zinc environments and compared the resulting crack growth rates. The second strategy varied zinc levels at the midterm of single specimen SCCGR tests and characterized the resulting crack growth rate effect through an electrical potential drop in-situ crack monitor. Results from the direct comparison and midterm changing chemistry tests did not discern a zinc influence; any apparent zinc influence is within test to test variability (∼1.5x change in crack growth rate). AEM, AUGER and ESCA crack tip fracture surface studies identified that zinc was not incorporated within crack tip oxides. These studies identified nickel rich crack tip oxides and spinel, with incorporated zinc, (∼5 atom percent) bulk surface oxides

  18. COST-EFFECTIVE METHOD FOR PRODUCING SELF SUPPORTED PALLADIUM ALLOY MEMBRANES FOR USE IN EFFICIENT PRODUCTION OF COAL DERIVED HYDROGEN

    Energy Technology Data Exchange (ETDEWEB)

    B. Lanning; J. Arps

    2005-08-31

    Efforts in this quarter were concentrated on developing vacuum processing procedures to produce thinner (<4 {micro}m-thick), defect-free films over larger areas (>100 cm{sup 2}). We continued to test three different types of rigid supporting substrates, thermally oxidized silicon (10 cm diameter), polished borosilicate glass (10 cm diameter), and soda-lime glass (>100 cm{sup 2} areas), each representing a different cost, surface roughness, and chemistry. Mechanical integrity, defect density, and release characteristics of the films, though similar for the oxidized silicon and borosilicate glass, were distinctly different for the inexpensive soda-lime (float) glass; i.e., more sensitive to surface impurities. In general, films less than 4 {micro}m-thick were shown to be very sensitive to surface condition of the supporting substrate, particularly in the case of the soda-lime glass, to the point where surface strain overrode and dominated the intrinsic bulk stresses that are produced during the growth process. Therefore, in the near term (over the next quarter), large area films (>100 cm{sup 2}) will be produced at a minimum thickness of 5 {micro}m while further development will be conducted in subsequent quarters to reduce membrane thickness in large area films. Continued hydrogen permeation experiments and characterization of 5 and 10 {micro}m-thick, Pd-Cu films, with compositions near the 60/40 (Pd/Cu phase boundary) in combination with air oxidation treatments to improve performance. Pure hydrogen permeability for an as-received, 5 {micro}m film at 400 C was determined to be 1.3 x 10{sup -4} cm{sup 3}(STP) {center_dot} cm/cm{sup 2} {center_dot} s {center_dot} cmHg{sup 0.5} at steady state. Even a membrane {approx} 10 {micro}m-thick, exhibited a steady state hydrogen flux of 32 cm{sup 3}(STP)/cm{sup 2}min after air exposure, which, when normalized for DOE's Office of Fossil Energy's specified hydrogen flux with a {Delta}P of 100 psi and a permeate

  19. On Diffusion and Permeation

    KAUST Repository

    Peppin, Stephen S. L.

    2009-01-01

    Diffusion and permeation are discussed within the context of irreversible thermodynamics. A new expression for the generalized Stokes-Einstein equation is obtained which links the permeability to the diffusivity of a two-component solution and contains the poroelastic Biot-Willis coefficient. The theory is illustrated by predicting the concentration and pressure profiles during the filtration of a protein solution. At low concentrations the proteins diffuse independently while at higher concentrations they form a nearly rigid porous glass through which the fluid permeates. The theoretically determined pressure drop is nonlinear in the diffusion regime and linear in the permeation regime, in quantitative agreement with experimental measurements. © 2009 Walter de Gruyter, Berlin, New York.

  20. Effect of the 718 alloy metallurgical status on hydrogen embrittlement; Effet de l'etat metallurgique de l'alliage 718 sur la fragilisation par l'hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    Galvano, F.; Andrieu, E.; Blanc, Ch.; Odemer, G.; Ter-Ovanessian, B.; Cocheteau, N.; Holstein, A.; Reboul, Ch. [Universite de Toulouse, CIRIMAT, UPS/CNRS/INPT, 31 - Toulouse (France); Clouez, J.M. [AREVA NP 69 - Lyon (France)

    2010-03-15

    The Inconel 718 is a nickel superalloy which is widely used in the nuclear industry, but is sensitive to hydrogen embrittlement induced by corrosion and stress corrosion cracking phenomena, and by the presence of dissolved hydrogen in pressurized water reactor environments. As this alloy is hardened by precipitation of different intermetallic phases, it appeared that the presence of these precipitates has a strong influence on the hydrogen embrittlement. The authors report the study of the nature and effect of the different traps (intermetallic phases, carbides or their interfaces) on the hydrogen embrittlement susceptibility of the 718 alloy, and more particularly on the observed failure modes. Experiments are performed on tensile samples in which hydrogen content can be measured. The type and grain size of the observed microstructures are given with respect with the thermal treatment, as well as the mechanical properties with or without hydrogen loading

  1. The changes in the electronic structure of B2 FeAl alloy with a Fe antisite and absorbed hydrogen

    International Nuclear Information System (INIS)

    Gonzalez, E.A.; Jasen, P.V.; Luna, R.; Bechthold, P.; Juan, A.; Brizuela, G.

    2009-01-01

    The electronic structure and bonding in a B2 FeAl alloy with and without hydrogen interaction with a Fe antisite were computed using a density functional theoretical method. The hydrogen absorption turns out to be a favorable process. The hydrogen was found close to an octahedral site where one of its Al capped is replaced by a Fe antisite. The Fe-H distance is of 1.45 A same as the Al-H distance. The density of states (DOS) curves show several peaks below the d metal band which is made up mostly of hydrogen based states (>50% H 1s ) while the metal contribution in this region includes mainly s and p orbitals. An electron transfer of nearby 0.21e - comes from the metal to the H. The overlap population values reveal metal-metal bond breaking, the intermetallic bond being the most affected. The H bond mainly with the Al atom and the reported Fe-H overlap population is much lower than that corresponding to FePd alloys and BCC Fe. The changes in the overlap population show the Fe-Al bond is weakened nearly 41.5% after H absorption, while the Fe-Fe bond is only weakened 34.5%. H also develops a stronger bond with the Al atoms. The main bond is developed with Al being twice stronger than Fe-H.

  2. Evaluation of mechanical property data on the 2219 aluminum alloy and application of the data to the design of liquid hydrogen tankage

    Science.gov (United States)

    Witzell, W. E.

    1977-01-01

    The potential use of thin guage 2219 aluminum alloy for airborne liquid hydrogen tankage was examined. Existing data were processed using the Newman two parameter equation, a prediction was made for the life expectancy of a hypothetical liquid hydrogen tank, and additional experimental data were generated in an attempt to correct the deficiencies in the existing data.

  3. Effect of temperature and dissolved hydrogen on oxide films formed on Ni and Alloy 182 in simulated PWR water

    International Nuclear Information System (INIS)

    Mendonça, R.; Bosch, R.-W.; Van Renterghem, W.; Vankeerberghen, M.; Araújo Figueiredo, C. de

    2016-01-01

    Alloy 182 is a nickel-based weld metal, which is susceptible to stress corrosion cracking in PWR primary water. It shows a peak in SCC susceptibility at a certain temperature and hydrogen concentration. This peak is related to the electrochemical condition where the Ni to NiO transition takes place. One hypothesis is that the oxide layer at this condition is not properly developed and so the material is not optimally protected against SCC. Therefore the oxide layer formed on Alloy 182 is investigated as a function of the dissolved hydrogen concentration and temperature around this Ni/NiO transition. Exposure tests were performed with Alloy 182 and Ni coupons in a PWR environment at temperatures between 300 °C and 345 °C and dissolved hydrogen concentration between 5 and 35 cc (STP)H 2 /kg. Post-test analysis of the formed oxide layers were carried out by SEM, EDS and XPS. The exposure tests with Ni coupons showed that the Ni/NiO transition curve is at a higher temperature than the curve based on thermodynamic calculations. The exposure tests with Alloy 182 showed that oxide layers were present at all temperatures, but that the morphology changed from spinel crystals to needle like oxides when the Ni/NiO transition curve was approached. Oxide layers were present below the Ni/NiO transition curve i.e. when the Ni coupon was still free of oxides. In addition an evolved slip dissolution model was proposed that could explain the observed experimental results and the peak in SCC susceptibility for Ni-based alloys around the Ni/NiO transition. - Highlights: • Exposure tests with Ni-coupons showed that the Ni/NiO transition curve shifted to more oxidizing conditions. • The Ni specimens tested in PWR water were free of oxides at all temperatures. • The exposure tests with Alloy 182 showed that oxide layers were present at all temperatures. • The Alloy 182 surface morphology changed from spinel crystals to needle like oxides when the Ni/NiO curve was approached

  4. Effect of temperature and dissolved hydrogen on oxide films formed on Ni and Alloy 182 in simulated PWR water

    Energy Technology Data Exchange (ETDEWEB)

    Mendonça, R. [CAPES Foundation, Ministry of Education, Brasilia (Brazil); Bosch, R.-W., E-mail: rbosch@sckcen.be [SCK-CEN, Boeretang 200, 2400 Mol (Belgium); Van Renterghem, W.; Vankeerberghen, M. [SCK-CEN, Boeretang 200, 2400 Mol (Belgium); Araújo Figueiredo, C. de [CDTN/CNEN, Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, MG (Brazil)

    2016-08-15

    Alloy 182 is a nickel-based weld metal, which is susceptible to stress corrosion cracking in PWR primary water. It shows a peak in SCC susceptibility at a certain temperature and hydrogen concentration. This peak is related to the electrochemical condition where the Ni to NiO transition takes place. One hypothesis is that the oxide layer at this condition is not properly developed and so the material is not optimally protected against SCC. Therefore the oxide layer formed on Alloy 182 is investigated as a function of the dissolved hydrogen concentration and temperature around this Ni/NiO transition. Exposure tests were performed with Alloy 182 and Ni coupons in a PWR environment at temperatures between 300 °C and 345 °C and dissolved hydrogen concentration between 5 and 35 cc (STP)H{sub 2}/kg. Post-test analysis of the formed oxide layers were carried out by SEM, EDS and XPS. The exposure tests with Ni coupons showed that the Ni/NiO transition curve is at a higher temperature than the curve based on thermodynamic calculations. The exposure tests with Alloy 182 showed that oxide layers were present at all temperatures, but that the morphology changed from spinel crystals to needle like oxides when the Ni/NiO transition curve was approached. Oxide layers were present below the Ni/NiO transition curve i.e. when the Ni coupon was still free of oxides. In addition an evolved slip dissolution model was proposed that could explain the observed experimental results and the peak in SCC susceptibility for Ni-based alloys around the Ni/NiO transition. - Highlights: • Exposure tests with Ni-coupons showed that the Ni/NiO transition curve shifted to more oxidizing conditions. • The Ni specimens tested in PWR water were free of oxides at all temperatures. • The exposure tests with Alloy 182 showed that oxide layers were present at all temperatures. • The Alloy 182 surface morphology changed from spinel crystals to needle like oxides when the Ni/NiO curve was

  5. Determination of hydrogen in zirconium and its alloys by melt extraction under carrier gas flow using thermal conductivity cell as detector

    International Nuclear Information System (INIS)

    Akhtar, J.; Ahmed, M.; Mohammad, B.; Jan, S.; Waqar, F.

    1987-06-01

    In the production of zirconium metal and its alloys the presence of hydrogen impurity affects mechanical and corrosion resistance properties of the product. Therefore, determination of hydrogen contents of the product is necessary. Conditions for its analysis by melt extraction under carrier gas stream using thermal conductivity cell as detector were studied and optimised. The method is capable of measuring hydrogen impurity in parts per million range. (author)

  6. Structural, hydrogen storage and thermodynamic properties of some mischmetal-nickel alloys with partial substitutions for nickel

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, E. Anil; Maiya, M. Prakash [Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Murthy, S. Srinivasa [Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India)], E-mail: ssmurthy@iitm.ac.in; Viswanathan, B. [National Centre for Catalysis Research, Indian Institute of Technology Madras, Chennai 600036 (India)

    2009-05-12

    Mischmetal-nickel (Mm-Ni) alloys with single (Al) and multiple (Al, Co, Mn, Fe) substitutions for Ni are studied for their structural, hydrogen storage and thermodynamic properties. The alloys considered are MmNi{sub 5}, MmNi{sub 4.7}Al{sub 0.3,} MmNi{sub 4.5}Al{sub 0.5}, MmNi{sub 4.2}Al{sub 0.8} and MmNi{sub 4}Al for single substitution, and MmNi{sub 3.9}Co{sub 0.8}Mn{sub 0.2}Al{sub 0.1}, MmNi{sub 3.8}Co{sub 0.7}Mn{sub 0.3}Al{sub 0.2}, MmNi{sub 3.7}Co{sub 0.7}Mn{sub 0.3}Al{sub 0.3}, MmNi{sub 3.6}Co{sub 0.6}Mn{sub 0.3}Al{sub 0.3}Fe{sub 0.2} and MmNi{sub 3.5}Co{sub 0.4}Mn{sub 0.4}Al{sub 0.4}Fe{sub 0.3} for multiple substitutions. The XRD patterns of all the alloys show single phase with the reflection peaks related to the CaCu{sub 5} hexagonal structure. All the multiple substituted alloys absorb and desorb hydrogen at sub-atmospheric pressures. The equilibrium pressure and hysteresis decrease, while enthalpy of formation ({delta}H) and plateau slope increase with increase in unit cell volume, indicating an increase in the stability of the alloys.

  7. Hydrogen storage properties of LaMgNi3.6M0.4 (M = Ni, Co, Mn, Cu, Al) alloys

    International Nuclear Information System (INIS)

    Yang, Tai; Zhai, Tingting; Yuan, Zeming; Bu, Wengang; Xu, Sheng; Zhang, Yanghuan

    2014-01-01

    Highlights: • La–Mg–Ni system AB 2 -type alloys were prepared by induction melting. • Structures and lattice parameters were analysed by XRD. • Hydrogen absorption/desorption performances were studied. • Mechanisms of hydrogen absorption capacity fading were investigated. - Abstract: LaMgNi 3.6 M 0.4 (M = Ni, Co, Mn, Cu, Al) alloys were prepared through induction melting process. The phase compositions and crystal structures were characterised via X-ray diffraction (XRD). The hydrogen storage properties, including activation performance, hydrogen absorption capacity, cycle stability, alloy particle pulverisation and plateau pressure, were systemically investigated. Results show that Ni, Co, Mn and Cu substitution alloys exhibit multiphase structures comprising the main phase LaMgNi 4 and the secondary phase LaNi 5 . However, the secondary phase of the Al substitution alloy changes into LaAlNi 4 . The lattice parameters and cell volumes of the LaMgNi 4 phase follow the order Ni < Co < Al < Cu < Mn. Activation is simplified through partial substitution of Ni with Al, Cu and Co. The hydrogen absorption capacities of all of the alloys are approximately 1.7 wt.% at the first activation process; however, they rapidly decrease with increasing cycle number. In addition, the stabilities of hydriding and dehydriding cycles decrease in the order Al > Co > Ni > Cu > Mn. Hydriding processes result in numerous cracks and amorphisation of the LaMgNi 4 phase in the alloys. The p–c isotherms were determined by a Sieverts-type apparatus. Two plateaus were observed for the Ni, Co and Al substitution alloys, whereas only one plateau was found for Mn and Cu. This result was caused by the amorphisation of the LaMgNi 4 phase during the hydriding cycles. Reversible absorption and desorption of hydrogen are difficult to achieve. Substitutions of Ni with Co, Mn, Cu and Al significantly influence the reduction of hysteresis between hydriding and dehydriding

  8. Low alloy steels that minimize the hydrogen-carbide reaction. Final technical report, October 1, 1978-September 30, 1979. Part I

    Energy Technology Data Exchange (ETDEWEB)

    Kar, R. J.; Parker, E. R.; Zackay, V. F.

    1979-01-01

    This report presents results obtained during the first year of a research program to investigate important metallurgical parameters that control the reactions of hydrogen with carbides in steels. Preliminary work included a detailed literature review of th phenomenon of decarburization and methane bubble formation in steels and a suitable experimental technique for investigating hydrogen attack in laboratory conditions was established. Detailed microstructural-mechanical property evaluations were carried out on two series of alloys; the first was based on a plain carbon steel to which binary and ternary alloy additions were made to vary the carbide structure and morphology and assess these effects on the observed hydrogen attack resistance. The second group of steels consisted of commercial Mn-Mo-Ni (A 533 B) and Cr-Mo (A 542 type) steels and their alloy modifications, with a view towards developing steels with improved hydrogen attack resistance.

  9. Selective Hydrogenation of Biomass-derived Furfural over Supported Ni3Sn2 Alloy: Role of Supports

    Directory of Open Access Journals (Sweden)

    Rodiansono Rodiansono

    2016-03-01

    Full Text Available A highly active and selective hydrogenation of biomass-derived furfural into furfuryl alcohol was achieved using supported single phase Ni3Sn2 alloy catalysts. Various supports such as active carbon (AC, g-Al2O3, Al(OH3, ZnO, TiO2, ZrO2, MgO, Li-TN, and SiO2 have been employed in order to understand the role of the support on the formation of Ni3Sn2 alloy phase and its catalytic performance. Supported Ni3Sn2 alloy catalysts were synthesised via a simple hydrothermal treatment of the mixture of aqueous solution of nickel chloride hexahydrate and ethanol solution of tin(II chloride dihydrate in presence of ethylene glycol at 423 K for 24 h followed by H2 treatment at 673 K for 1.5 h, then characterised by using ICP-AES, XRD, H2- and N2-adsorption. XRD profiles of samples showed that the Ni3Sn2 alloy phases are readily formed during hydrothermal processes and become clearly observed at 2θ = 43-44o after H2 treatment. The presence of Ni3Sn2 alloy species that dispersed on the supports is believed to play a key role in highly active and selective hydrogenation of biomass-derived furfural towards furfuryl alcohol. Ni3Sn2 on TiO2 and ZnO supports exhibited much lower reaction temperature to achieved >99% yield of furfuryl alcohol product compared with other supports. The effects of loading amount of Ni-Sn, reaction conditions (temperature and time profile on the activity and selectivity towards the desired product are systematically discussed. Copyright © 2016 BCREC GROUP. All rights reserved Received: 10th November 2015; Revised: 31st December 2015; Accepted: 5th January 2016 How to Cite: Rodiansono, R., Astuti, M.D., Khairi, S., Shimazu, S. (2016. Selective Hydrogenation of Biomass-derived Furfural over Supported Ni3Sn2 Alloy: Role of Supports. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1: 1-9. (doi:10.9767/bcrec.11.1.393.1-9 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.393.1-9

  10. Effect of boron addition on the microstructure and electrochemical performance of La2Mg(Ni0.85Co0.15)9 hydrogen storage alloy

    International Nuclear Information System (INIS)

    Zhang Yanghuan; Dong Xiaoping; Wang Guoqing; Guo Shihai; Ren Jiangyuan; Wang Xinlin

    2006-01-01

    In order to improve the electrochemical performances of La-Mg-Ni system (PuNi 3 -type) hydrogen storage alloy, a trace of boron was added in La 2 Mg(Ni 0.85 Co 0.15 ) 9 and rapid quenching techniques were used. La 2 Mg(Ni 0.85 Co 0.15 ) 9 B x (x = 0, 0.05, 0.1, 0.15, 0.2) hydrogen storage alloys were prepared by casting and rapid quenching. The microstructures and electrochemical performances of the as-cast and quenched alloys were determined and measured. The effects of the boron content and the quenching rate on the microstructures and electrochemical performances of the alloys were investigated in detail. The obtained results show that the as-cast and quenched alloys are composed of the (La, Mg)Ni 3 phase (PuNi 3 structure), the LaNi 5 phase and the LaNi 2 phase. A trace of the Ni 2 B phase exists in the as-cast alloys containing boron. The Ni 2 B phase in the alloys containing boron nearly disappears after rapid quenching and the relative amount of each phase in the alloys changes with the variety of the quenching rate. The addition of boron obviously enhances the cycle stability of the as-cast and quenched alloys. The effects of boron content on the capacities of the as-cast and quenched alloys are different. The capacities of the as-cast alloys monotonously decrease with the increase of boron content, whereas the capacities of the as-quenched alloys have a maximum value with the change of boron content. The as-cast and quenched alloys have an excellent activation performance

  11. Catalytic effect of additional metallic phases on the hydrogen absorption behavior of a Zr-Based alloy

    International Nuclear Information System (INIS)

    Ruiz, F; Peretti, H; Castro, E; Real, S; Visitin, A; Triaca, W

    2005-01-01

    The electrochemical hydrogen absorption of electrodes containing Zr 0 .9Ti 0 .1(Ni 0 .5Mn 0 .25Cr 0 .20V 0 .05) 2 is studied in alkaline media by monitoring the activation and discharge capacity along charge-discharge cycling.The considered alloy is tested in both as melted and annealed condition in order to investigate the catalytic effect of small amounts of micro segregated secondary phases of the Zr-Ni system. Since these catalytic phases are only present in the as melted alloys, tests are also carried out using a composite material elaborated from powders of the annealed alloy with the addition of 18 wt.% of the suspected catalytic phases, melted separately.The hydrogen absorption-desorption behavior for the different cases is discussed and correlated with the metallurgical characterization of the materials.The catalytic effects are studied employing cyclic voltammetry and electrochemical impedance techniques. The results are analyzed in terms of a developed physicochemical model<