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Sample records for antimony base alloys

  1. Comparison of modification with strontium and the refining with antimony in A 356 aluminium alloys

    International Nuclear Information System (INIS)

    Strontium and Antimony treated A356 aluminium alloy samples were metallographically characterized in the as cast and solution and aged conditions. Antimony treated alloy has shown slower spheroidizing kinetics of the Silicon particles during solution treatment, lower porosity level and higher tensile strength and elongation than Strontium treated one. (author)

  2. Evaluations of antimony and strontium interaction in an Al–Si–Cu–Zn die cast alloy

    Energy Technology Data Exchange (ETDEWEB)

    Farahany, Saeed, E-mail: saeedfarahany@gmail.com; Idris, Mohd Hasbullah; Ourdjini, Ali

    2014-05-01

    Graphical abstract: - Highlights: • Probable interactions between Sb and Sr in a complex Al–Si alloy were evaluated. • Sequence of addition did not affect thermal and microscopical characteristics. • Threshold ratio for the Sb and Sr interaction is proposed. - Abstract: The interaction between antimony and strontium in an ADC12 die casting alloy is investigated comprehensively by using a computer aided cooling curve thermal analysis coupled with microstructure inspection. The results of the thermal analysis show significant changes in Al–Si eutectic reaction based on different concentrations of Sb and Sr. Sb reduces the efficiency of Sr in modifying the eutectic Si. Based upon the data obtained in this study, the threshold Sr/Sb ratio should exceed about 0.5 in order to obtain fully modified structure. Moreover, a pre-eutectic reaction of Al{sub 2}Si{sub 2}Sr intermetallic was detected for high concentrations of Sr.

  3. Influence of antimony on the mechanical properties and gas content of alloy AlSi6Cu4

    OpenAIRE

    D. Medlen; D. Bolibruchova

    2011-01-01

    Aluminium alloys based on Al-Si are used in automotive and aerospace industries. AlSi6Cu4 alloy is used the complicated castings, whichmust comply high strength requirements. Strength characteristics can also be affected by the modifiers: Na, Sr, Sb. In the li terature ismentioned, that AlSi6Cu4 modified by sodium and strontium has negative effect - increases of the gas absorption. Modification of AlSi6Cu4 alloy by antimony, is still not mentioned in the literature. The article gives the effe...

  4. Spin dynamics of complex oxides, bismuth-antimony alloys, and bismuth chalcogenides

    Science.gov (United States)

    Sahin, Cuneyt

    The emerging field of spintronics relies on the manipulation of electron spin in order to use it in spin-based electronics. Such a paradigm change has to tackle several challenges including finding materials with sufficiently long spin lifetimes and materials which are efficient in generating pure spin currents. This thesis predicts that two types of material families could be a solution to the aforementioned challenges: complex oxides and bismuth based materials. We derived a general approach for constructing an effective spin-orbit Hamiltonian which is applicable to all nonmagnetic materials. This formalism is useful for calculating spin-dependent properties near an arbitrary point in momentum space. We also verified this formalism through comparisons with other approaches for III-V semiconductors, and its general applicability is illustrated by deriving the spin-orbit interaction and predicting spin lifetimes for strained strontium titanate (STO) and a two-dimensional electron gas in STO (such as at the LAO/STO interface). Our results suggest robust spin coherence and spin transport properties in STO related materials even at room temperature. In the second part of the study we calculated intrinsic spin Hall conductivities for bismuth-antimony (BISb) semimetals with strong spin-orbit couplings, from the Kubo formula and using Berry curvatures evaluated throughout the Brillouin zone from a tight-binding Hamiltonian. Nearly crossing bands with strong spin-orbit interaction generate giant spin Hall conductivities in these materials, ranging from 474 ((h/e)O--1cm--1) for bismuth to 96((h/e)O--1cm --1) for antimony; the value for bismuth is more than twice that of platinum. The large spin Hall conductivities persist for alloy compositions corresponding to a three-dimensional topological insulator state, such as Bi0.83Sb0.17. The spin Hall conductivity could be changed by a factor of 5 for doped Bi, or for Bi0.83Sb0.17, by changing the chemical potential by 0.5 e

  5. Electrodeposition of SnSbCu Alloy on Copper from an Electrolyte with Varied Content of Antimony Chloride

    Science.gov (United States)

    Valeeva, A. Kh.; Valeev, I. Sh.

    2015-10-01

    The microstructure and chemical composition of electrodeposited alloys of the SnSbCu system with varied concentration of antimony chloride in the electrolyte have been investigated. It is shown that during electrodeposition mechanical-mixture alloys are not formed, but rather intermetallic compounds. It is found that increasing the concentration of antimony chloride in the electrolyte leads to a decrease in the tin content and cracking of the coating.

  6. The influence of remelting on the properties of AlSi6Cu4 alloy modified by antimony

    OpenAIRE

    D. Medlen; D. Bolibruchova

    2012-01-01

    The paper deals with the problem of multiple remelting influence on AlSi6Cu4 alloy modified by antimony on chosen mechanical characteristics, microstructure and gas content. This foundry alloy is used mostly in automotive industry. Foundry Aluminum-Silicon alloys are also used in number of industrial weight sensitive applications because of their low weight and very good castability and good mechanical properties. Modifiers are usually added to molten aluminum-silicon alloys to refine the eut...

  7. A thermodynamic investigation of liquid gold-antimony alloys

    International Nuclear Information System (INIS)

    The enthalpies of mixing of liquid Au-Sb alloys were determined between 906 and 1028 K giving ΔmixHom = xSb xAu (-11.234-1.1078xSb + 5.713xSb2) kJ mol-1. The minimum was found at xSb = 0.45 with ΔmixHom = -2.62 ± 0.2 kJ mol-1 contrary to published measurements on liquid Au-Sb alloys. The limiting partial molar enthalpy of Au in Sb at 935 K was measured to Δmixhom(Au, liq, in ∞Sb, liq) = -6.05 ± 0.4 kJ mol-1. The enthalpy of formation of the solid compound AuSb2 determined at 298 K by solution calorimetry in liquid Sb, ΔfHom(AuSb2) = -5.40 ± 0.6 kJ mol-1, is found in fair agreement with literature data. DTA measurements were performed on the Au-rich part of the liquidus and a new liquidus curve is suggested between Au and the eutectic concentration. The eutectic point was found at 630.37 ± 0.25 K and xSb 0.350. (orig.)

  8. The influence of remelting on the properties of AlSi6Cu4 alloy modified by antimony

    Directory of Open Access Journals (Sweden)

    D. Medlen

    2012-01-01

    Full Text Available The paper deals with the problem of multiple remelting influence on AlSi6Cu4 alloy modified by antimony on chosen mechanical characteristics, microstructure and gas content. This foundry alloy is used mostly in automotive industry. Foundry Aluminum-Silicon alloys are also used in number of industrial weight sensitive applications because of their low weight and very good castability and good mechanical properties. Modifiers are usually added to molten aluminum-silicon alloys to refine the eutectic phase particle shape and improve the mechanical properties of the final cast products and Al-Si alloys cast properties.

  9. EFFECT OF GRAIN BOUNDARY SEGREGATION OF ANTIMONY ON RELAXATION AT GRAIN BOUNDARIES IN SILICON-IRON ALLOYS

    OpenAIRE

    Iwasaki, Y.; Fujimoto, K

    1981-01-01

    A sharp grain boundary peak appears in both 2 and 3% silicon-iron alloys due to a substitutional solute of silicon. This peak is highly sensitive to the segregation of the third element of antimony and, contrary to orthodox solute peaks in binary and ternary alloys, largely decreases in magnitude on heating after a segregation treatment. The subsequent measurement on cooling returns the peak to the ordinary magnitude. As a function of annealing time at a temperature of segregation, the height...

  10. The determination of the thermodynamic activity of antimony in alpha-iron

    International Nuclear Information System (INIS)

    In this paper a method is suggested for determining the thermodynamic activity of antimony dissolved in alpha-iron, based on the study of antimony distribution between the two phases: liquid lead and solid iron. By this method, it was found that solid solutions of antimony in alpha-iron can be distinguished by positive divergences from the ideal state. Over a fairly wide range of concentrations, solutions of antimony in iron obey Henry's law. Special experiments on the distribution of antimony between lead and liquid iron showed that in the liquid state also the iron-antimony system is marked by positive divergences from the ideal state when small concentrations of antimony are present. The heat required for the solution of antimony in alpha-iron, and the excess partial molar entropy, were calculated from the activity temperature. The results were used for accurately locating the line showing the solubility limit of antimony in alpha-iron. Since alloys of antimony with iron were obtained by diffusion saturation and not by cooling from the liquid state, there was no liquefaction. Thus the lattice constant of the alloys and its relation to the alloy concentration could be reliably determined. The solubility limit established from X-ray data agrees with that obtained with Sb124. (author)

  11. Resistance to Arsenic- and Antimony-Based Drugs

    OpenAIRE

    Milena Salerno; Arlette Garnier-Suillerot

    2003-01-01

    Organic arsenicals were the first antimicrobial agents specifically synthesized for the treatment of infectious diseases such as syphilis and sleeping sickness. For the treatment of diseases caused by trypanosomatid parasites, organic derivatives of arsenic and the related metalloid antimony are still the drugs of choice. Arsenic trioxide, As203, has been used for a long time in traditional Chinese medicines for treatment of various diseases, and it has recently been shown to be clinically ac...

  12. lVIICROSTRUCTURE AND EUTECTIC MORPHOLOGY OF AL-12.5°/o Si ALLOY REFINED WITH ANTIMONY

    Directory of Open Access Journals (Sweden)

    Funda Kahraman

    2007-01-01

    Full Text Available Modification of Al-Si cast alloys can be achieved in two different ways, namely by additions of certain eleınents orwith rapid cooling rate. Modifications of the Al-Si al1oys are carried out extensivcly in industry to improve themechanical properties, particularly ductility. In this study, the effects of antiınony addition.s and growth rate on theınicrostructure and eutectic morphology on the directionally solidified Al- 1 2.5°/o Si cutectic all oy has beeninvestigated. The results showed that antimony can be identified as a grain refıner. Over modification occurs in Al-12.5 °/oSi alloy when modifier is present in the amount of 1 %Sb results in AISb compound.

  13. Low-Power Super-resolution Readout with Antimony Bismuth Alloy Film as Mask layer

    Institute of Scientific and Technical Information of China (English)

    JIANG Lai-Xin; WU Yi-Qun; WANG Yang; WEI Jing-Song; GAN Fu-Xi

    2009-01-01

    Sb-Bi alloy films are proposed as a new kind of super-resolution mask layer with low readout threshold power. Using the Sb-Bi alloy film as a mask layer and SiN as a protective layer in a read-only memory disc, the super-resolution pits with diameters of 38Onm are read out by a dynamic setup, the laser wavelength is 78Onto and the numerical aperture of pickup lens is 0.45. The effects of the Sb-Bi thin film thickness, laser readout power and disc rotating velocity on the readout signal are investigated. The results show that the threshold laser power of super-resolution readout of the Sb-Bi mask layer is about 0.5roW, and the corresponding carrier-to-noise ratio is about 20dB at the film thickness of 5Ohm. The super-resolution mechanism of the Sb-Bi alloy mask layer is discussed based on its temperature dependence of reflection.

  14. Antimony Toxicity

    Directory of Open Access Journals (Sweden)

    Shyam Sundar

    2010-12-01

    Full Text Available Antimony toxicity occurs either due to occupational exposure or during therapy. Occupational exposure may cause respiratory irritation, pneumoconiosis, antimony spots on the skin and gastrointestinal symptoms. In addition antimony trioxide is possibly carcinogenic to humans. Improvements in working conditions have remarkably decreased the incidence of antimony toxicity in the workplace. As a therapeutic, antimony has been mostly used for the treatment of leishmaniasis and schistosomiasis. The major toxic side-effects of antimonials as a result of therapy are cardiotoxicity (~9% of patients and pancreatitis, which is seen commonly in HIV and visceral leishmaniasis co-infections. Quality control of each batch of drugs produced and regular monitoring for toxicity is required when antimonials are used therapeutically.

  15. Determination and modeling of the thermodynamic properties of liquid calcium–antimony alloys

    International Nuclear Information System (INIS)

    The thermodynamic properties of Ca–Sb alloys were determined by emf measurements in a cell configured as Ca(s)|CaF2|Ca–Sb over the temperature range 550–830 °C. Activity coefficients of Ca and Sb, enthalpy, Gibbs free energy, and entropy of mixing of Ca–Sb alloys were calculated for xCa 2 associate, and the molecular interaction volume model (MIVM). For the first time, the MIVM was used successfully to model the activity coefficients of a system with high-melting intermetallics, reducing the number of fitting parameters necessary from 5 (regular associated model) to 2 (MIVM). From the interaction parameters optimized by fitting at 800 °C, the activity coefficient of Ca was predicted at 650 °C, with an average error of less than 0.6% in the emf value.

  16. Comparative study on the corrosion behavior of the cold rolled and hot rolled low-alloy steels containing copper and antimony in flue gas desulfurization environment

    Science.gov (United States)

    Park, S. A.; Kim, J. G.; He, Y. S.; Shin, K. S.; Yoon, J. B.

    2014-12-01

    The correlation between the corrosion and microstructual characteristics of cold rolled and hot rolled low-alloy steels containing copper and antimony was established. The corrosion behavior of the specimens used in flue gas desulfurization systems was examined by electrochemical and weight loss measurements in an aggressive solution of 16.9 vol % H2SO4 + 0.35 vol % HCl at 60°C, pH 0.3. It has been shown that the corrosion rate of hot rolled steel is lower than that of cold rolled steel. The corrosion rate of cold rolled steel was increased by grain refinement, inclusion formation, and preferred grain orientation.

  17. Interface Promoted Reversible Mg Insertion in Nanostructured Tin-Antimony Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yingwen; Shao, Yuyan; Parent, Lucas R.; Sushko, Maria L.; Li, Guosheng; Sushko, Petr; Browning, Nigel D.; Wang, Chong M.; Liu, Jun

    2015-11-11

    This paper demonstrates intermetallic compounds SnSb are highly active materials for reversibly hosting Mg ions. Compared with monometallic Sn and Sb, SnSb alloy exhibited exceptionally high reversible capacity (420 mAh/g), excellent rate capability and good cyclic stability. Mg insertion into pristine SnSb involves an activation process to complete, which induces particle breakdown and results in phase segregation to Sn-rich and Sb-rich phases. Both experimental analysis and DFT simulation suggest that the Sn-rich phase is particularly active and provides most of the capacity whereas the Sb-rich phase is not as active, and the interface between these two phases play a key role in promoting the formation and stabilization of the cubic Sn phase that is more favorable for fast and reversible Mg insertion. We further show that activated SnSb alloy has good compatibility with simple Mg electrolytes. Overall, this work could provide new approaches for designing materials capable of reversible Mg ion insertion and new opportunities for understanding Mg electrochemistry.

  18. Effects of Antimony on Microstructure and Mechanical Properties of A356 Alloy%Sb变质A356合金的组织与力学性能

    Institute of Scientific and Technical Information of China (English)

    申玉彬; 王明星; 刘志勇; 刘忠侠; 宋天福

    2012-01-01

    The modification of antimony (Sb) on eutectic Si phase in A356 aluminum-silicon alloy and the effects of rare earth (RE) on the modification efficiency of antimony were investigated, and effects of the strontium (Sr) on A356 alloy were analyzed comparatively. The tensile and fatigue properties of the Sb, Sb+RE or Sr modified A356 alloys were also analyzed comparatively. The results show that Sb can refine the eutectic silicon phases in A356 alloy significantly from plate-like into fine fibrous structure. , However, the modification efficiency of Sb is.lower than Sr. The modification effects can be improved obviously in Sb modified A356 aluminum-silicon alloy with the addition of a little RE, decreasing of Sb content for achieving the desirable modification efficiency. The tensile properties of the Sb or Sb + RE modified A356 alloys are lower than those of the Sr modified alloy, however, the fatigue properties are superior to that of the Sr modified alloy, which may be attributed to the higher compactness and less casting defects in Sb or Sb+RE modified alloys compared with the Sr modified alloy.%研究了Sb对A356合金中共晶Si相的变质作用及RE对Sb变质作用的影响,并且与Sr变质合金进行了比较,对Sb、Sb+RE以及Sr变质A356合金的拉伸及疲劳性能进行了对比.结果表明,Sb的A356合金变质使共晶Si相由粗大的板片状转化为细小的纤维状,但变质效果不如Sr;用Sb变质处理时,加入少量的RE,可明显改善Sh的变质效果,降低获得最佳变质效果的Sb含量;合金变质的力学性能不如Sr变质合金,但疲劳性能明显优于Sr变质合金.其原因可能与Sb或Sb+RE变质合金的致密性较Sr变质合金高、铸造缺陷较Sr变质合金少有关.

  19. Thermodynamic Properties of Liquid Silver-Antimony-Tin Alloys Determined from Electrochemical and Calorimetric Measurements

    Science.gov (United States)

    Łapsa, Joanna; Onderka, Bogusław

    2016-05-01

    The thermodynamic properties of liquid Ag-Sb-Sn alloys were obtained through use of the drop solution calorimetric method and electromotive force (emf) measurements of galvanic cells with a yttria stabilized zirconia (YSZ) solid electrolyte. The experiments were carried out along Ag0.25Sb0.75, Ag0.5Sb0.5 and Ag0.75Sb0.25 sections of the ternary system in the temperature range from 973 K to 1223 K. From the measured emf, the tin activity in liquid solutions of Ag-Sb-Sn was determined for the first time. The partial and integral enthalpy of mixing were determined from calorimetric measurements at two temperatures. These measurements were performed along two cross-sections: Sb0.5Sn0.5 at 912 K and 1075 K, and Ag0.75Sb0.25 at 1075 K. Both experimental data sets were used to find ternary interaction parameters by applying the Redlich-Kister-Muggianu model of the substitutional solution. Consequently, the set of parameters describing the thermodynamic properties of the liquid phase was derived.

  20. Thermodynamic Properties of Liquid Silver-Antimony-Tin Alloys Determined from Electrochemical and Calorimetric Measurements

    Science.gov (United States)

    Łapsa, Joanna; Onderka, Bogusław

    2016-08-01

    The thermodynamic properties of liquid Ag-Sb-Sn alloys were obtained through use of the drop solution calorimetric method and electromotive force (emf) measurements of galvanic cells with a yttria stabilized zirconia (YSZ) solid electrolyte. The experiments were carried out along Ag0.25Sb0.75, Ag0.5Sb0.5 and Ag0.75Sb0.25 sections of the ternary system in the temperature range from 973 K to 1223 K. From the measured emf, the tin activity in liquid solutions of Ag-Sb-Sn was determined for the first time. The partial and integral enthalpy of mixing were determined from calorimetric measurements at two temperatures. These measurements were performed along two cross-sections: Sb0.5Sn0.5 at 912 K and 1075 K, and Ag0.75Sb0.25 at 1075 K. Both experimental data sets were used to find ternary interaction parameters by applying the Redlich-Kister-Muggianu model of the substitutional solution. Consequently, the set of parameters describing the thermodynamic properties of the liquid phase was derived.

  1. Pentavalent Antimonials: New Perspectives for Old Drugs

    Directory of Open Access Journals (Sweden)

    Raul R. Ribeiro

    2009-06-01

    Full Text Available Pentavalent antimonials, including meglumine antimoniate and sodium stibogluconate, have been used for more than half a century in the therapy of the parasitic disease leishmaniasis. Even though antimonials are still the first-line drugs, they exhibit several limitations, including severe side effects, the need for daily parenteral administration and drug resistance. The molecular structure of antimonials, their metabolism and mechanism of action are still being investigated. Some recent studies suggest that pentavalent antimony acts as a prodrug that is converted to active and more toxic trivalent antimony. Other works support the direct involvement of pentavalent antimony. Recent data suggest that the biomolecules, thiols and ribonucleosides, may mediate the actions of these drugs. This review will summarize the progress to date on the chemistry and biochemistry of pentavalent antimony. It will also present the most recent works being done to improve antimonial chemotherapy. These works include the development of simple synthetic methods for pentavalent antimonials, liposome-based formulations for targeting the Leishmania parasites responsible for visceral leishmaniasis and cyclodextrin-based formulations to promote the oral delivery of antimony.

  2. Vacuum Evaporation Technology for Treating Antimony-Rich Anode Slime

    Science.gov (United States)

    Qiu, Keqiang; Lin, Deqiang; Yang, Xuelin

    2012-11-01

    A vacuum evaporation technology for treating antimony-rich anode slime was developed in this work. Experiments were carried out at temperatures from 873 K to 1073 K and residual gas pressures from 50 Pa to 600 Pa. During vacuum evaporation, silver from the antimony-rich anode slime was left behind in the distilland in a silver alloy containing antimony and lead, and antimony trioxide was evaporated. The experimental results showed that 92% by weight of antimony can be removed, and the silver content in the alloy was up to 12.84%. The antimony trioxide content in the distillate was more than 99.7%, and the distillate can be used directly as zero-grade antimony trioxide (China standard).

  3. First-Principles Study of Antimony Doping Effects on the Iron-Based Superconductor CaFe(SbxAs1-x)2

    Science.gov (United States)

    Nagai, Yuki; Nakamura, Hiroki; Machida, Masahiko; Kuroki, Kazuhiko

    2015-09-01

    We study antimony doping effects on the iron-based superconductor CaFe(SbxAs1-x)2 by using the first-principles calculation. The calculations reveal that the substitution of a doped antimony atom into As of the chainlike As layers is more stable than that into FeAs layers. This prediction can be checked by experiments. Our results suggest that doping homologous elements into the chainlike As layers, which only exist in the novel 112 system, is responsible for rising up the critical temperature. We discuss antimony doping effects on the electronic structure. It is found that the calculated band structures with and without the antimony doping are similar to each other within our framework.

  4. First-principles study of antimony doping effects on the iron-based superconductor CaFe(SbxAs1−x)2

    International Nuclear Information System (INIS)

    We study antimony doping effects on the iron-based superconductor CaFe(SbxAs1−x)2 by using the first-principles calculation. The calculations reveal that the substitution of a doped antimony atom into As of the chainlike As layers is more stable than that into FeAs layers. This prediction can be checked by experiments. Our results suggest that doping homologous elements into the chainlike As layers, which only exist in the novel 112 system, is responsible for rising up the critical temperature. We discuss antimony doping effects on the electronic structure. It is found that the calculated band structures with and without the antimony doping are similar to each other within our framework. (author)

  5. On the segregation behavior of tin and antimony at grain boundaries of polycrystalline bcc iron

    Czech Academy of Sciences Publication Activity Database

    Lejček, Pavel; Šandera, P.; Horníková, J.; Pokluda, J.; Godec, M.

    2016-01-01

    Roč. 363, Feb (2016), 140-144. ISSN 0169-4332 R&D Projects: GA ČR GAP108/12/0144 Institutional support: RVO:68378271 Keywords : grain boundary segregation * tin * antimony * Fe based alloy * AES quantification Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.711, year: 2014

  6. Potentiometric stripping analysis of antimony based on carbon paste electrode modified with hexathia crown ether and rice husk

    International Nuclear Information System (INIS)

    Highlights: → Potentiometric stripping analysis (PSA) employed for the determination of antimony. → Hexathia-18C6 and rice husk modified carbon paste electrode developed for the analysis. → Lowest detection limit obtained for the determination of Sb(III) using PSA. → Analysis of Sb in pharmaceutical formulations, human hair, blood serum, urine and sea water. → Rice husk used as a modifier for the first time in electrochemistry. - Abstract: An electrochemical method based on potentiometric stripping analysis (PSA) employing a hexathia 18C6 (HT18C6) and rice husk (RH) modified carbon paste electrode (HT18C6-RH-CPE) has been proposed for the subnanomolar determination of antimony. The characterization of the electrode surface has been carried out by means of scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy and chronocoulometry. By employing HT18C6-RH-CPE, a 12-fold enhancement in the PSA signal (dt/dE) was observed as compared to plain carbon paste electrode (PCPE). Under the optimized conditions, dt/dE (s V-1) was proportional to the Sb(III) concentration in the range of 1.42 x 10-8 to 6.89 x 10-11 M (r = 0.9944) with the detection limit (S/N = 3) of 2.11 x 10-11 M. The practical analytical utilities of the modified electrode were demonstrated by the determination of antimony in pharmaceutical formulations, human hair, sea water, urine and blood serum samples. The prepared modified electrode showed several advantages, such as simple preparation method, high sensitivity, very low detection limit and excellent reproducibility. Moreover, the results obtained for antimony analysis in commercial and real samples using HT18C6-RH-CPE and those obtained by inductively coupled plasma-atomic emission spectrometry (ICP-AES) are in agreement at the 95% confidence level.

  7. Potentiometric stripping analysis of antimony based on carbon paste electrode modified with hexathia crown ether and rice husk

    Energy Technology Data Exchange (ETDEWEB)

    Gadhari, Nayan S.; Sanghavi, Bankim J. [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai 400098 (India); Srivastava, Ashwini K., E-mail: aksrivastava@chem.mu.ac.in [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai 400098 (India)

    2011-10-03

    Highlights: {yields} Potentiometric stripping analysis (PSA) employed for the determination of antimony. {yields} Hexathia-18C6 and rice husk modified carbon paste electrode developed for the analysis. {yields} Lowest detection limit obtained for the determination of Sb(III) using PSA. {yields} Analysis of Sb in pharmaceutical formulations, human hair, blood serum, urine and sea water. {yields} Rice husk used as a modifier for the first time in electrochemistry. - Abstract: An electrochemical method based on potentiometric stripping analysis (PSA) employing a hexathia 18C6 (HT18C6) and rice husk (RH) modified carbon paste electrode (HT18C6-RH-CPE) has been proposed for the subnanomolar determination of antimony. The characterization of the electrode surface has been carried out by means of scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy and chronocoulometry. By employing HT18C6-RH-CPE, a 12-fold enhancement in the PSA signal (dt/dE) was observed as compared to plain carbon paste electrode (PCPE). Under the optimized conditions, dt/dE (s V{sup -1}) was proportional to the Sb(III) concentration in the range of 1.42 x 10{sup -8} to 6.89 x 10{sup -11} M (r = 0.9944) with the detection limit (S/N = 3) of 2.11 x 10{sup -11} M. The practical analytical utilities of the modified electrode were demonstrated by the determination of antimony in pharmaceutical formulations, human hair, sea water, urine and blood serum samples. The prepared modified electrode showed several advantages, such as simple preparation method, high sensitivity, very low detection limit and excellent reproducibility. Moreover, the results obtained for antimony analysis in commercial and real samples using HT18C6-RH-CPE and those obtained by inductively coupled plasma-atomic emission spectrometry (ICP-AES) are in agreement at the 95% confidence level.

  8. Terbium base alloy

    International Nuclear Information System (INIS)

    Composition of terbium-5-7 % gadolinium alloy with high magnetostriction sensitivity (180x10-8 Oe) is suggested. The alloy is designed for usage under cryogenic temperature within 500-1500 Oe fields. Magnetostriction sensitivity of the suggested alloy is by 2-2.5 times higher, than that of well-known before one. 1 tab

  9. Uranium-Based Cermet Alloys

    International Nuclear Information System (INIS)

    The paper describes certain features of dispersion-hardened uranium-based cermets. As possible hardening materials, consideration was given to UO2, UC, Al2O3, MgO and UBe13. Data were obtained on the behaviour of uranium alloys containing the above-mentioned admixtures during creep tests, short-term strength tests and cyclic thermal treatment. The corrosion resistance o f UBe13-based uranium alloys was also studied. )author)

  10. First-principle study of antimony doping effects on the iron-based superconductor CaFe(Sb$_{x}$As$_{1-x}$)$_{2}$

    OpenAIRE

    Nagai, Yuki; Nakamura, Hiroki; Machida, Masahiko; Kuroki, Kazuhiko

    2015-01-01

    We study antimony doping effects in the iron-based superconductor CaFe(Sb$_{x}$As$_{1-x}$)$_{2}$ by using the first-principle calculation. The calculations reveal that the substitution of the doped antimony atom into As of the chainlike As layers is more stable than that in FeAs layers. This prediction can be checked by experiments. Our results suggest that doping homologous elements into the chainlike As layers existing only in novel 112 system is responsible for rising up the critical tempe...

  11. Determination of PM10 deposition based on antimony flux to selected urban surfaces

    International Nuclear Information System (INIS)

    Deposition of PM10 particles to several types of urban surfaces was investigated within this study. Antimony was chosen as a tracer element to calculate dry deposition velocities for PM10, since antimony proved to be present almost exclusively in PM10 particles in ambient urban air. During 18 months, eight sampling sites in Berlin and Karlsruhe, two cities in Germany, were operated. PM10 concentrations and dry deposition were routinely sampled as two week averages. Additionally, leaf-samples were collected at three sites with tall vegetation. The obtained deposition velocities ranged from 0.8 to 1.3 cm s-1 at roadside sites and from 0.4 to 0.5 cm s-1 at the other sites. With reference to the whole canopy, additional deposition velocities of about 0.5 cm s-1 were obtained for leaf surfaces. As a consequence, it can be concluded that vegetation-covered areas beside streets show the highest potential to capture particles in urban areas. - Highlights: → Deposition velocities of PM10 were determined using Sb as a tracer element. → Dry PM10 deposition velocities ranged from 0.8 to 1.3 cm s-1 at roadside sites. → Dry PM10 deposition velocities ranged from 0.4 to 0.5 cm s-1 at other urban sites. → Additional deposition velocities of 0.5 cm s-1 were obtained for leaf surfaces. - Antimony is used as a tracer element to calculate dry deposition velocities of PM10 particles to selected urban surfaces.

  12. Effect of antimony on the corrosion behavior of low-alloy steel for flue gas desulfurization system

    International Nuclear Information System (INIS)

    The alloying effect of Sb in a new low-alloy steel for the purpose of FGD materials was investigated by potentiodynamic polarization, linear polarization resistance measurement, electrochemical impedance spectroscopy (EIS) and weight loss measurements in an aggressive solution of 16.9 vol.% H2SO4 + 0.35 vol.% HCl (modified green death solution) at 60 deg. C, pH -0.3. All measurements confirmed the marked improvement in the corrosion behavior of the low-alloy steel via the addition of a small amount of Sb, particularly for the 0.10Sb steel. Pitting corrosion was detected by scanning electron microscopy (SEM) on the surface of blank steel and 0.05Sb steel, but not 0.10Sb steel, after weight loss measurements. X-ray photoelectron spectroscopy (XPS) analysis of the corroded surfaces after EIS and linear polarization measurements showed that the decrease in corrosion rates was due to the formation of a protective Sb2O5 oxide film on the surface of the Sb-containing steels. Moreover, the addition of 0.10% Sb stimulated the development of high corrosion inhibiting, Cu-containing compounds which further inhibited the anodic and cathodic reactions

  13. A novel composite material based on antimony(III) oxide and amorphous silica

    Energy Technology Data Exchange (ETDEWEB)

    Zemnukhova, Ludmila A. [Institute of Chemistry, Far-Eastern Branch, Russian Academy of Sciences, 690022 Vladivostok (Russian Federation); Panasenko, Alexander E., E-mail: panasenko@ich.dvo.ru [Institute of Chemistry, Far-Eastern Branch, Russian Academy of Sciences, 690022 Vladivostok (Russian Federation)

    2013-05-01

    The composite material nSb₂O₃·mSiO₂·xH₂O was prepared by hydrolysis of SbCl₃ and Na₂SiO₃ in an aqueous medium. It has been shown that the composition of the material is influenced by the ratio of the initial components and the acidity of the reaction medium. The morphology of the material particles and its specific surface area have been determined. The thermal and optic properties were also investigated. - Graphical abstract: Novel composite material containing amorphous silica and crystal antimony(III) oxide has been synthesized by hydrolysis of SbCl₃ and Na₂SiO₃ in an aqueous medium. Highlights: • The composite material nSb₂O₃·mSiO₂·xH₂O was prepared in an aqueous medium. • The composition of the material is controllable by a synthesis conditions. • The morphology of the material and its optic properties have been determined.

  14. Optical properties of Eu3+-doped antimony-oxide-based low phonon disordered matrices

    Science.gov (United States)

    Som, Tirtha; Karmakar, Basudeb

    2010-01-01

    A new series of monolithic Eu2O3-doped high antimony oxide (40-80 mol%) content disordered matrices (glasses) of low phonon energy (about 600 cm-1) in the K2O-B2O3-Sb2O3 (KBS) system was prepared by the melt-quench technique. Infrared reflection spectroscopy was used to establish the low phonon energy of the glasses. Amorphicity and devitrification of the glasses were confirmed by x-ray diffraction analysis. UV-vis absorption spectra of Eu3+ have been measured and the band positions have been justified with quantitative calculation of the nephelauxetic parameter and covalent bonding characteristics of the host. These Eu2O3-doped glasses upon excitation at 393 nm radiation exhibit six emission bands in the range 500-750 nm due to their low phonon energy. Of these, the magnetic dipole ^{5}\\mathrm {D}_{0} \\to {}^{7} \\mathrm {F_{1}} transition shows small Stark splitting while the electric dipole ^{5}\\mathrm {D}_{0} \\to {}^{7}\\mathrm {F}_{2} transition undergoes remarkable Stark splitting into two components. They have been explained by the crystal field effect. The Judd-Ofelt parameters, Ωt = 2,4,6, were also evaluated and the change of Ωt with the glass composition was correlated with the asymmetric effect at Eu3+ ion sites and the fundamental properties like covalent character and optical basicity. We are the first to report the spectroscopic properties of the Eu3+ ion in KBS low phonon antimony glasses.

  15. Novel methods for the encapsulation of meglumine antimoniate into liposomes

    Directory of Open Access Journals (Sweden)

    F. Frézard

    2000-07-01

    Full Text Available The antimonial drug, meglumine antimoniate, was successfully encapsulated in dehydration-rehydration vesicles and in freeze-dried empty liposomes (FDELs. High encapsulation efficiencies (from 28 to 58% and low weight ratios of lipids to encapsulated antimony (from 1:0.15 to 1:0.3 were achieved. These formulations, contrary to those obtained by conventional methods, can be stored as intermediate lyophilized forms and reconstituted just before use. The efficacy of FDEL-encapsulated meglumine antimoniate was evaluated in hamsters experimentally infected with Leishmania chagasi. A significant reduction of liver parasite burdens was observed in animals treated with this preparation, when compared to control animals treated with empty liposomes. In contrast, free meglumine antimoniate was found to be inefficient when administered at a comparable dose of antimony. This novel liposome-based meglumine antimoniate formulation appears to be promising as a pharmaceutical product for the treatment of visceral leishmaniasis.

  16. Promoting the Hydrosilylation of Benzaldehyde by Using a Dicationic Antimony-Based Lewis Acid: Evidence for the Double Electrophilic Activation of the Carbonyl Substrate.

    Science.gov (United States)

    Hirai, Masato; Cho, Junsang; Gabbaï, François P

    2016-05-01

    The concomitant activation of carbonyl substrates by two Lewis acids has been investigated by using [1,2-(Ph2 MeSb)2 C6 H4 ](2+) ([1](2+) ), an antimony-based bidentate Lewis acid obtained by methylation of the corresponding distibine. Unlike the simple stibonium cation [Ph3 MeSb](+) , dication [1](2+) efficiently catalyzes the hydrosilylation of benzaldehyde under mild conditions. The catalytic activity of this dication is correlated to its ability to doubly activate the carbonyl functionality of the organic substrate. This view is supported by the isolation of [1-μ2 -DMF][OTf]2 , an adduct, in which the DMF oxygen atom bridges the two antimony centers. PMID:26934491

  17. Effect of Vanadium and Titanium substitution over an antimony-based mixed oxide catalysts for propane ammoxidation to acrylonitrile

    International Nuclear Information System (INIS)

    Antimony (Sb) oxide is known to be the active phase for the ammoxidation of propane to acrylonitrile (ACN). The influenced of V and/ or Ti on the physicochemical properties of Sb-based mixed oxide catalysts were studied using catalysts prepared by slurry method. The dried precursor was calcined in air at 350-600 degree Celsius for a total of 10 h. The active phases in Sb-promoted catalysts were determined using X-ray Diffraction (XRD) while the changes in microstructure of these catalysts were studied using physical adsorption of nitrogen gas. The catalytic activities of these catalysts were tested in a fixed-bed reactor with online GC at 420 degree Celsius with reaction feed (% v) of 5.8:7:17.4 for propane, ammonia and oxygen, respectively. Results show that promotional of Sb with V and/ or Ti has an effect on the chemical environment of the Sb-mixed oxide catalysts, leading to differences in catalytic activity of these catalysts. (author)

  18. Thermodynamic Considerations of Contamination by Alloying Elements of Remelted End-of-Life Nickel- and Cobalt-Based Superalloys

    Science.gov (United States)

    Lu, Xin; Matsubae, Kazuyo; Nakajima, Kenichi; Nakamura, Shinichiro; Nagasaka, Tetsuya

    2016-06-01

    Cobalt and nickel are high-value commodity metals and are mostly used in the form of highly alloyed materials. The alloying elements used may cause contamination problems during recycling. To ensure maximum resource efficiency, an understanding of the removability of these alloying elements and the controllability of some of the primary alloying elements is essential with respect to the recycling of end-of-life (EoL) nickel- and cobalt-based superalloys by remelting. In this study, the distribution behaviors of approximately 30 elements that are usually present in EoL nickel- and cobalt-based superalloys in the solvent metal (nickel, cobalt, or nickel-cobalt alloy), oxide slag, and gas phases during the remelting were quantitatively evaluated using a thermodynamic approach. The results showed that most of the alloying elements can be removed either in the slag phase or into the gas phase. However, the removal of copper, tin, arsenic, and antimony by remelting is difficult, and they remain as tramp elements during the recycling. On the other hand, the distribution tendencies of iron, molybdenum, and tungsten can be controlled by changing the remelting conditions. To increase the resource efficiency of recycling, preventing contamination by the tramp elements and identifying the alloying compositions of EoL superalloys are significantly essential, which will require the development of efficient prior alloy-sorting systems and advanced separation technologies.

  19. Nickel-base alloys combat corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, D.C. [VDM Technologies Corp., Houston, TX (United States); Herda, W. [Krupp-VDM GmbH, Werdohl (Germany)

    1995-06-01

    The modern chemical process industry must increase production efficiency to remain competitive. Manufacturers typically meet this challenge by utilizing higher temperatures and pressures, and more-corrosive catalysts. At the same time, the industry has to solve the technical and commercial problems resulting from rigid environmental regulations. To overcome these obstacles, new alloys having higher levels of corrosion resistance have been developed. These materials are based on increased understanding of the physical metallurgy of nickel-base alloys, especially the role of alloying elements. Results of many studies have led to innovations in nickel-chromium-molybdenum alloys containing both high and low amounts of nickel. Higher molybdenum and chromium contents, together with nitrogen additions, have opened up an entirely new class of alloys having unique properties. In addition, a new chromium-base, fully wrought super stainless steel shows excellent promise in solving many corrosion problems. These newer alloys have the ability to combat uniform corrosion, localized corrosion, and stress-corrosion cracking in the harsh halogenic environment of the chemical process industry. This article briefly lists some of the major highlights and corrosion data on recent nickel-chromium-molybdenum and nickel-molybdenum alloys, and the development of a chromium-base, wrought super-austenitic alloy known as Nicrofer 3033 (Alloy 33). Some comparisons with existing alloys are presented, along with a few commercial applications.

  20. Bulk amorphous Mg-based alloys

    DEFF Research Database (Denmark)

    Pryds, Nini

    The present paper describes the preparation and properties of bulk amorphous quarternary Mg-based alloys and the influence of additional elements on the ability of the alloy to form bulk amorphous. The main goal is to find a Mg-based alloy system which shows both high strength to weight ratio and a...... low glass transition temperature. The alloys were prepared by using a relatively simple technique, i.e. rapid cooling of the melt in a copper wedge mould. The essential structural changes that are achieved by going from the amorphous to the crystalline state through the supercooled liquid state are...... discussed in this paper. On the basis of these measurements phase diagrams of the different systems were constructed. Finally, it is demonstrated that when pressing the bulk amorphous alloy onto a metallic dies at temperatures within the supercooled liquid region, the alloy faithfully replicates the surface...

  1. Surface Bond Strength in Nickel Based Alloys

    OpenAIRE

    Ramesh, Ganesh; Padmanabhan, T. V.; Ariga, Padma; Joshi, Shalini; Bhuminathan, S.; Vijayaraghavan, Vasantha

    2012-01-01

    Bonding of ceramic to the alloy is essential for the longevity of porcelain fused to metal restorations. Imported alloys used now a days in processing them are not economical. So this study was conducted to evaluate and compare the bond strength of ceramic material to nickel based cost effective Nonferrous Materials Technology Development Center (NFTDC), Hyderabad and Heraenium S, Heraeus Kulzer alloy. An Instron testing machine, which has three-point loading system for the application of loa...

  2. Shape memory alloy based motor

    Indian Academy of Sciences (India)

    S V Sharma; M M Nayak; N S Dinesh

    2008-10-01

    Design and characterization of a new shape memory alloy wire based Poly Phase Motor has been reported in this paper. The motor can be used either in stepping mode or in servo mode of operation. Each phase of the motor consists of an SMA wire with a spring in series. The principle of operation of the poly phase motor is presented. The motor resembles a stepper motor in its functioning though the actuation principles are different and hence has been characterized similar to a stepper motor. The motor can be actuated in either direction with different phase sequencing methods, which are presented in this work. The motor is modelled and simulated and the results of simulations and experiments are presented. The experimental model of the motor is of dimension 150 mm square, 20 mm thick and uses SMA wire of 0·4 mm diameter and 125 mm of length in each phase.

  3. Iron-based amorphous alloys and methods of synthesizing iron-based amorphous alloys

    Science.gov (United States)

    Saw, Cheng Kiong; Bauer, William A.; Choi, Jor-Shan; Day, Dan; Farmer, Joseph C.

    2016-05-03

    A method according to one embodiment includes combining an amorphous iron-based alloy and at least one metal selected from a group consisting of molybdenum, chromium, tungsten, boron, gadolinium, nickel phosphorous, yttrium, and alloys thereof to form a mixture, wherein the at least one metal is present in the mixture from about 5 atomic percent (at %) to about 55 at %; and ball milling the mixture at least until an amorphous alloy of the iron-based alloy and the at least one metal is formed. Several amorphous iron-based metal alloys are also presented, including corrosion-resistant amorphous iron-based metal alloys and radiation-shielding amorphous iron-based metal alloys.

  4. Cloud point extraction combined with electrothermal atomic absorption spectrometry for the speciation of antimony(III) and antimony(V) in food packaging materials

    International Nuclear Information System (INIS)

    A simple, sensitive method for the speciation of inorganic antimony by cloud point extraction combined with electrothermal atomic absorption spectrometry (ETAAS) is presented and evaluated. The method based on the fact that formation of a hydrophobic complex of antimony(III) with ammonium pyrrolidine dithiocarbamate (APDC) at pH 5.0 and subsequently the hydrophobic complex enter into surfactant-rich phase, whereas antimony(V) remained in aqueous solutions. Antimony(III) in surfactant-rich phase was analyzed by ETAAS after dilution by 0.2 mL nitric acid in methanol (0.1 M), and antimony(V) was calculated by subtracting antimony(III) from the total antimony after reducing antimony(V) to antimony(III) by L-cysteine. The main factors affecting the cloud point extraction, such as pH, concentration of APDC and Triton X-114, equilibrium temperature and incubation time, sample volume were investigated in detail. Under the optimum conditions, the detection limit (3σ) of the proposed method was 0.02 ng mL-1 for antimony(III), and the relative standard deviation was 7.8% (c = 1.0 ng mL-1, n = 7). The proposed method was successfully applied to speciation of inorganic antimony in the leaching solutions of different food packaging materials with satisfactory results.

  5. Cloud point extraction combined with electrothermal atomic absorption spectrometry for the speciation of antimony(III) and antimony(V) in food packaging materials.

    Science.gov (United States)

    Jiang, Xiuming; Wen, Shengping; Xiang, Guoqiang

    2010-03-15

    A simple, sensitive method for the speciation of inorganic antimony by cloud point extraction combined with electrothermal atomic absorption spectrometry (ETAAS) is presented and evaluated. The method based on the fact that formation of a hydrophobic complex of antimony(III) with ammonium pyrrolidine dithiocarbamate (APDC) at pH 5.0 and subsequently the hydrophobic complex enter into surfactant-rich phase, whereas antimony(V) remained in aqueous solutions. Antimony(III) in surfactant-rich phase was analyzed by ETAAS after dilution by 0.2 mL nitric acid in methanol (0.1M), and antimony(V) was calculated by subtracting antimony(III) from the total antimony after reducing antimony(V) to antimony(III) by l-cysteine. The main factors affecting the cloud point extraction, such as pH, concentration of APDC and Triton X-114, equilibrium temperature and incubation time, sample volume were investigated in detail. Under the optimum conditions, the detection limit (3 sigma) of the proposed method was 0.02 ng mL(-1) for antimony(III), and the relative standard deviation was 7.8% (c=1.0 ng mL(-1), n=7). The proposed method was successfully applied to speciation of inorganic antimony in the leaching solutions of different food packaging materials with satisfactory results. PMID:19853991

  6. Pharmacokinetic of antimony in mice with cutaneous Leishmaniasis

    International Nuclear Information System (INIS)

    Cutaneous Leishmaniasis (CL) remains a major world health problem, with about 1.5 million new cases each year. Caused by protozoa Leishmania, in South America, this infection can vary from a chronic skin ulcer, to an erosive mucosal disease and severe facial disfigurement. Pentavalent antimony (Sb+5) as sodium stibogluconate (Pentostam) or meglumine antimoniate (Glucantime) are main drugs for treating most forms of human leishmaniasis. For six decades, despite the recent developments, the effective therapy to cutaneous leishmaniasis has been based on long parenteral courses of such drugs, even though these are fairly costly, toxic and inconvenient to use, without adequate knowledge on their pharmacokinetics or mechanism of action. Pharmacokinetics studies could be based on bioactive traceable drugs, usually with radioactive isotopes, but antimony radioisotopes are unavailable commercially. Neutron irradiation is a powerful tool in the analysis of mineral content of samples, for antimony, there are at least two main isotopes that could be formed after neutron irradiation in nuclear reactor. The aim of the present study was to construct antimony salts with those radioisotopes to obtain tracers to compare the pharmacokinetic and the tissue distribution of neutron irradiated meglumine antimoniate in healthy and cutaneous leishmaniasis experimentally infected mice. Meglumine antimoniate, (Glucantime, Aventis, S.P, Brazil), was neutron irradiated inside the IEA-R1 nuclear reactor (IPEN/CNEN-SP), producing two radioisotopes 122Sb and 124Sb. Its biodistribution was verified in BALB/c mice experimentally infected with Leishmania (Leishmania) Amazonensis, which received a single intraperitoneal dose of the drug. At different times after injection, the tissues and blood were excised and activity measured in a NaI (Tl) scintillation counter. Compared with the healthy mice, experimentally infected mice had significantly lower maximum concentration of antimony and high uptake in

  7. Pharmacokinetic of antimony in mice with cutaneous Leishmaniasis

    Energy Technology Data Exchange (ETDEWEB)

    Borborema, Samanta E.T.; Nascimento, Nanci do [Instituto de Pesquisas Energeticas e Nucleares IPEN/CNEN-SP, Sao Paulo, SP (Brazil). Lab. de Biologia Molecular]. E-mails: samanta@usp.br; nnascime@ipen.br; Andrade Junior, Heitor F. de [Instituto de Pesquisas Energeticas e Nucleares IPEN/CNEN-SP, Sao Paulo, SP (Brazil). Lab. de Biologia Molecular; Instituto de Medicina Tropical de Sao Paulo, Sao Paulo, SP (Brazil); E-mail: hfandrad@usp.br; Osso Junior, Joao A. [Instituto de Pesquisas Energeticas e Nucleares IPEN/CNEN-SP, Sao Paulo, SP (Brazil). Centro de Radiofarmacia]. E-mail: jaosso@ipen.br

    2007-07-01

    Cutaneous Leishmaniasis (CL) remains a major world health problem, with about 1.5 million new cases each year. Caused by protozoa Leishmania, in South America, this infection can vary from a chronic skin ulcer, to an erosive mucosal disease and severe facial disfigurement. Pentavalent antimony (Sb{sup +5}) as sodium stibogluconate (Pentostam) or meglumine antimoniate (Glucantime) are main drugs for treating most forms of human leishmaniasis. For six decades, despite the recent developments, the effective therapy to cutaneous leishmaniasis has been based on long parenteral courses of such drugs, even though these are fairly costly, toxic and inconvenient to use, without adequate knowledge on their pharmacokinetics or mechanism of action. Pharmacokinetics studies could be based on bioactive traceable drugs, usually with radioactive isotopes, but antimony radioisotopes are unavailable commercially. Neutron irradiation is a powerful tool in the analysis of mineral content of samples, for antimony, there are at least two main isotopes that could be formed after neutron irradiation in nuclear reactor. The aim of the present study was to construct antimony salts with those radioisotopes to obtain tracers to compare the pharmacokinetic and the tissue distribution of neutron irradiated meglumine antimoniate in healthy and cutaneous leishmaniasis experimentally infected mice. Meglumine antimoniate, (Glucantime, Aventis, S.P, Brazil), was neutron irradiated inside the IEA-R1 nuclear reactor (IPEN/CNEN-SP), producing two radioisotopes {sup 122}Sb and {sup 124}Sb. Its biodistribution was verified in BALB/c mice experimentally infected with Leishmania (Leishmania) Amazonensis, which received a single intraperitoneal dose of the drug. At different times after injection, the tissues and blood were excised and activity measured in a NaI (Tl) scintillation counter. Compared with the healthy mice, experimentally infected mice had significantly lower maximum concentration of antimony

  8. Iron - based bulk amorphous alloys

    Directory of Open Access Journals (Sweden)

    R. Babilas

    2010-07-01

    Full Text Available Purpose: The paper presents a structure characterization, thermal and soft magnetic properties analysis of Fe-based bulk amorphous materials in as-cast state and after crystallization process. In addition, the paper gives some brief review about achieving, formation and structure of bulk metallic glasses as a special group of amorphous materials.Design/methodology/approach: The studies were performed on Fe72B20Si4Nb4 metallic glass in form of ribbons and rods. The amorphous structure of tested samples was examined by X-ray diffraction (XRD, transmission electron microscopy (TEM and scanning electron microscopy (SEM methods. The thermal properties of the glassy samples were measured using differential thermal analysis (DTA and differential scanning calorimetry (DSC. The magnetic properties contained initial and maximum magnetic permeability, coercive force and magnetic after-effects measurements were determined by the Maxwell-Wien bridge and VSM methods.Findings: The X-ray diffraction and transmission electron microscopy investigations revealed that the studied as-cast bulk metallic glasses in form of ribbons and rods were amorphous. Two stage crystallization process was observed for studied bulk amorphous alloy. The differences of crystallization temperature between ribbons and rods with chosen thickness are probably caused by different amorphous structures as a result of the different cooling rates in casting process. The SEM images showed that studied fractures could be classified as mixed fractures with indicated two zones contained “river” and “smooth” areas. The changing of chosen soft magnetic properties (μr, Bs, Hc obtained for samples with different thickness is a result of the non-homogenous amorphous structure of tested metallic glasses. The annealing process in temperature range from 373 to 773 K causes structural relaxation of tested amorphous materials, which leads to changes in their physical properties. The qualitative

  9. F-Alloy: An Alloy Based Model Transformation Language

    OpenAIRE

    Gammaitoni, Loïc; Kelsen, Pierre

    2015-01-01

    Model transformations are one of the core artifacts of a model-driven engineering approach. The relational logic language Alloy has been used in the past to verify properties of model transformations. In this paper we introduce the concept of functional Alloy modules. In essence a functional Alloy module can be viewed as an Alloy module representing a model transformation. We describe a sublanguage of Alloy called F-Alloy that allows the specification of functional Alloy modules. Module...

  10. New Er{sup 3+} doped antimony oxide based glasses: Thermal analysis, structural and spectral properties

    Energy Technology Data Exchange (ETDEWEB)

    Ouannes, K. [Faculté des Sciences et de la Technologie, Université de Biskra, BP 145 RP, 07000, Biskra (Algeria); Lebbou, K., E-mail: kheirreddine.lebbou@univ-lyon1.fr [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622, Villeurbanne (France); Walsh, Brian-M. [NASA Langley Research Center, Hampton, VA, 23681 (United States); Poulain, M. [UMR 6226- Verres et Céramiques – Campus de Beaulieu, Université de Rennes1, 35042, Rennes (France); Alombert-Goget, G.; Guyot, Y. [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622, Villeurbanne (France)

    2015-11-15

    The novel oxide glass compositions based on Sb{sub 2}O{sub 3} are elaborated and characterized, in the system (90-X)Sb{sub 2}O{sub 3}–10Na{sub 2}O–XBi{sub 2}O{sub 3} (SNB). We are interested in bismuth rates incorporated into the glass, its effect on the different physical properties that have been measured, and especially, in radiative and spectroscopic properties of erbium doped SNB glasses. Differential scanning calorimeter (DSC) measurements show an improvement of the stability factor,ΔT, of the glasses, which can indicate a reinforcement of the network. Both FTIR and Raman spectra have also been considered in terms of bismuth influence. As a function of composition, we have principally measured optical absorption, visible and infrared emission, and lifetime. The Judd–Ofelt parameters measured from the absorption spectra have been used to calculate the radiative lifetime (τ{sub r}) and the stimulated emission cross section. The spectroscopic quality factor χ = Ω{sub 4}/Ω{sub 6} = 0.73, low phonon energy of ∼600–700 cm{sup −1}, a reduced quenching effect, and a high quantum efficiency of 90% for the 1.53 μm measured emission, by pumping at 980 nm, are in favor of promising laser applications. - Highlights: • Glass belonging to Er-doped Sb{sub 2}O{sub 3}–Na{sub 2}O–Bi{sub 2}O{sub 3} (SNB) system are elaborated and characterized. • The intensity parameters Ωt were obtained via the Judd–Ofelt theory. • The optical properties were studied as a function of glass composition.

  11. Passivation of alloys on titanium base

    International Nuclear Information System (INIS)

    Results of passivation studies on Ti-base alloys show that the inhibition of anodic processes on these alloys is determined not by the total thickness of passive film, but by its barrier layer. The protective properties of the barrier layer increase if the passive film is formed at anodic potentials more positive than +1.4V. They were determined not by chemical stability of barrier layer, but by an inhibition which is produced by this layer for ionic current along the anodic direction. The protective properties are related to character defectiveness and semiconductor properties of the barrier layer. Additions of Al, V, Mo, Zr, and Nb to titanium increase the anodic current in the passive state. Additions of Cr and Mn decrease this current, and Sn does not influence it. The direct electrochemical transition of titanium ions into solution (as TiO2+) is a main anodic process of titanium dissolution and its low alloyed alloys in the passive state. Double phase titanium alloys (after tempering) have a lower corrosion resistance than those in the homogeneous single phase state (after hardening). The less passive phase of double phase alloys dissolves perferentially. The less passive phases are: in the active state, α-phase; in transpassive state for Ti--Mo alloys, β-phase, containing in a high Mo percentage; and for Ti--Cr alloys, γ-phase, having more chromium. (U.S.)

  12. Cobalt doped antimony oxide nano-particles based chemical sensor and photo-catalyst for environmental pollutants

    International Nuclear Information System (INIS)

    Graphical abstract: A dichloromethane chemical sensor using cobalt antimony oxides has been fabricated. This sensor showed high sensitivity and will be a useful candidate for environmental and health monitoring. Also it showed high photo-catalytic activity and can be a good candidate as a photo-catalyst for organic hazardous materials. Highlights: ► Reusable chemical sensor. ► Green environmental and eco-friendly chemi-sensor. ► High sensitivity. ► Good candidate for environmental and health monitoring. - Abstract: Cobalt doped antimony oxide nano-particles (NPs) have been synthesized by hydrothermal process and structurally characterized by utilizing X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and Fourier transforms infrared spectrophotometer (FT-IR) which revealed that the synthesized cobalt antimony oxides (CoSb2O6) are well crystalline nano-particles with an average particles size of 26 ± 10 nm. UV–visible absorption spectra (∼286 nm) were used to investigate the optical properties of CoSb2O6. The chemical sensing of CoSb2O6 NPs have been primarily investigated by I–V technique, where dichloromethane is used as a model compound. The analytical performance of dichloromethane chemical sensor exhibits high sensitivity (1.2432 μA cm−2 mM−1) and a large linear dynamic range (1.0 μM–0.01 M) in short response time (10 s). The photo catalytic activity of the synthesized CoSb2O6 nano-particles was evaluated by degradation of acridine orange (AO), which degraded 58.37% in 200 min. These results indicate that CoSb2O6 nano-particles can play an excellent research impact in the environmental field.

  13. Cobalt doped antimony oxide nano-particles based chemical sensor and photo-catalyst for environmental pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Jamal, Aslam [Centre for Advanced Materials and Nano-Engineering (CAMNE) and Department of Chemistry, Faculty of Sciences and Arts, Najran University, P. O. Box 1988, Najran 11001 (Saudi Arabia); Rahman, Mohammed M. [Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Khan, Sher Bahadar, E-mail: drkhanmarwat@gmail.com [Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Faisal, Mohd. [Centre for Advanced Materials and Nano-Engineering (CAMNE) and Department of Chemistry, Faculty of Sciences and Arts, Najran University, P. O. Box 1988, Najran 11001 (Saudi Arabia); Akhtar, Kalsoom [Division of Nano Sciences and Department of Chemistry, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Rub, Malik Abdul; Asiri, Abdullah M.; Al-Youbi, Abdulrahman O. [Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia)

    2012-11-15

    Graphical abstract: A dichloromethane chemical sensor using cobalt antimony oxides has been fabricated. This sensor showed high sensitivity and will be a useful candidate for environmental and health monitoring. Also it showed high photo-catalytic activity and can be a good candidate as a photo-catalyst for organic hazardous materials. Highlights: Black-Right-Pointing-Pointer Reusable chemical sensor. Black-Right-Pointing-Pointer Green environmental and eco-friendly chemi-sensor. Black-Right-Pointing-Pointer High sensitivity. Black-Right-Pointing-Pointer Good candidate for environmental and health monitoring. - Abstract: Cobalt doped antimony oxide nano-particles (NPs) have been synthesized by hydrothermal process and structurally characterized by utilizing X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and Fourier transforms infrared spectrophotometer (FT-IR) which revealed that the synthesized cobalt antimony oxides (CoSb{sub 2}O{sub 6}) are well crystalline nano-particles with an average particles size of 26 {+-} 10 nm. UV-visible absorption spectra ({approx}286 nm) were used to investigate the optical properties of CoSb{sub 2}O{sub 6}. The chemical sensing of CoSb{sub 2}O{sub 6} NPs have been primarily investigated by I-V technique, where dichloromethane is used as a model compound. The analytical performance of dichloromethane chemical sensor exhibits high sensitivity (1.2432 {mu}A cm{sup -2} mM{sup -1}) and a large linear dynamic range (1.0 {mu}M-0.01 M) in short response time (10 s). The photo catalytic activity of the synthesized CoSb{sub 2}O{sub 6} nano-particles was evaluated by degradation of acridine orange (AO), which degraded 58.37% in 200 min. These results indicate that CoSb{sub 2}O{sub 6} nano-particles can play an excellent research impact in the environmental field.

  14. LASER CLADDING ON ALUMINIUM BASE ALLOYS

    OpenAIRE

    Pilloz, M.; Pelletier, J; Vannes, A.; Bignonnet, A.

    1991-01-01

    laser cladding is often performed on iron or titanium base alloys. In the present work, this method is employed on aluminum alloys ; nickel or silicon are added by powder injection. Addition of silicon leads to sound surface layers, but with moderated properties, while the presence of nickel induces the formation of hard intermetallic compounds and then to an attractive hardening phenomena ; however a recovery treatment has to be carried out, in order to eliminate porosity in the near surface...

  15. Post-CMOS FinFET integration of bismuth telluride and antimony telluride thin-film-based thermoelectric devices on SoI substrate

    KAUST Repository

    Aktakka, Ethem Erkan

    2013-10-01

    This letter reports, for the first time, heterogeneous integration of bismuth telluride (Bi2Te3) and antimony telluride (Sb 2Te3) thin-film-based thermoelectric ffect transistors) via a characterized TE-film coevaporationand shadow-mask patterning process using predeposition surface treatment methods for reduced TE-metal contact resistance. As a demonstration vehicle, a 2 × 2 mm2-sized integrated planar thermoelectric generator (TEG) is shown to harvest 0.7 μ W from 21-K temperature gradient. Transistor performance showed no significant change upon post-CMOS TEG integration, indicating, for the first time, the CMOS compatibility of the Bi2Te3 and Sb2Te3 thin films, which could be leveraged for realization of high-performance integrated micro-TE harvesters and coolers. © 2013 IEEE.

  16. Oxygen diffusion in vanadium-based alloys

    International Nuclear Information System (INIS)

    The experimental study of transport and equilibrium properties of oxygen in vanadium-based alloys was made by EMF measurements on solid electrolytic cells over the temperature range of 873 to 14230K. The oxygen diffusion in vanadium was not significantly modified by small additions of Ti, Cr, Ni, Nb and Ta. The increase in the activation energy for oxygen diffusion in the V-based alloys containing Cr, Ni, Nb and Ta probably reflects the effect of these substitutional solutes on the activity coefficient of oxygen. The oxygen activity was increased by the addition of 1 at % of Cr, Ni and Nb, and decreased by the addition of Ti and Ta. However, the effects in the alloys containing Nb and Ta are very small

  17. Irradiation creep of vanadium-base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, H.; Billone, M.C.; Strain, R.V.; Smith, D.L. [Argonne National Lab., IL (United States); Matsui, H. [Tohoku Univ. (Japan)

    1998-03-01

    A study of irradiation creep in vanadium-base alloys is underway with experiments in the Advanced Test Reactor (ATR) and the High Flux Isotope Reactor (HFIR) in the United States. Test specimens are thin-wall sealed tubes with internal pressure loading. The results from the initial ATR irradiation at low temperature (200--300 C) to a neutron damage level of 4.7 dpa show creep rates ranging from {approx}0 to 1.2 {times} 10{sup {minus}5}/dpa/MPa for a 500-kg heat of V-4Cr-4Ti alloy. These rates were generally lower than reported from a previous experiment in BR-10. Because both the attained neutron damage levels and the creep strains were low in the present study, however, these creep rates should be regarded as only preliminary. Substantially more testing is required before a data base on irradiation creep of vanadium alloys can be developed and used with confidence.

  18. 21 CFR 872.3710 - Base metal alloy.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Base metal alloy. 872.3710 Section 872.3710 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3710 Base metal alloy. (a) Identification. A base metal alloy is a device composed primarily of base metals, such as nickel, chromium, or cobalt, that...

  19. Creep of nickel-base alloys in high temperature water

    Energy Technology Data Exchange (ETDEWEB)

    Fish, J.S.; Attanasio, S.A.; Krasodomski, H.T.; Wilkening, W.W.; Was, G.S.; Cookson, J.; Yi, Y.

    1999-08-01

    Creep tests were performed to compare the creep behavior of commercial nickel-base alloys as a function of stress, temperature, and the environment. The results support earlier work that showed that low carbon alloys are more susceptible to creep and intergranular cracking than are high carbon alloys. Results also show a smaller influence of a water environment on the creep rate of commercial, creep-resistant alloys compared to high purity alloys.

  20. A novel voltammetric sensor based on carbon nanotubes and nanoparticles of antimony tin oxide for the determination of ractopamine.

    Science.gov (United States)

    Baytak, Aysegul Kutluay; Teker, Tugce; Duzmen, Sehriban; Aslanoglu, Mehmet

    2016-02-01

    An electrochemical sensor was prepared by the modification of a glassy carbon electrode (GCE) with carbon nanotubes (CNTs) and nanoparticles of antimony tin oxide (ATO). The surface layer was characterized by scanning electronmicroscopy (SEM), energy dispersive X-ray diffraction method (EDX) and ATR FT-IR spectroscopy. The proposed electrode was assessed in respect to the electro-oxidation of ractopamine. Compared with a bare GCE and a GCE electrode modified with CNTs, the ATONPs/CNTs/GCE exhibited a great catalytic activity towards the oxidation of ractopamine with a well-defined anodic peak at 600 mV. The current response was linear with the concentration of ractopamine over the range from 10 to 240 nM with a detection limit of 3.3 nM. The proposed electrode enabled the selective determination of ractopamine in the presence of high concentrations of ascorbic acid (AA), dopamine (DA) and uric acid (UA). The proposed electrode was successfully applied for the determination of ractopamine in feed and urine samples. The sensitive and selective determination of ractopamine makes the developed method of great interest for monitoring its therapeutic use and doping control purposes. PMID:26652385

  1. Implementation of thermal processes for feedstock recycling of bromine and antimony, with energy recovery, from plastics waste of electrical and electronic equipment (WEEE). Phase 1. Literature survey/status update, evaluation, and ranking of combustion, gasification, and pyrolysis based technologies

    Energy Technology Data Exchange (ETDEWEB)

    Boerrigter, H. [ECN Biomass, Petten (Netherlands)

    2000-11-01

    The bromine industry wants to process plastic Waste from Electrical and Electronic Equipment (WEEE), containing brominated flame retardants (BFRs), to recycle bromine, antimony, and other valuable metals, with energy recovery for sustainable production and closing the bromine loop at the End-of-Life. The motivation to perform the underlying study was that insufficient detailed information was available regarding the technical and economical feasibility of processing of WEEE with thermal processes (i.e. combustion, gasification, and pyrolysis-based technologies). The objective of the study was to make an inventory of available processes and evaluate them based on the following six criteria:Energy efficiency, Bromine and Antimony recovery, Emissions (legislation permits), General quality of residues/secondary products, Operational experience, and Profit expectations (ROI). 57 refs.

  2. Vanadium-base alloys for fusion reactor applications

    International Nuclear Information System (INIS)

    Vanadium-base alloys offer potentially significant advantages over other candidate alloys as a structural material for fusion reactor first wall/blanket applications. Although the data base is more limited than that for the other leading candidate structural materials, viz., austenitic and ferritic steels, vanadium-base alloys exhibit several properties that make them particularly attractive for the fusion reactor environment. This paper presents a review of the structural material requirements, a summary of the materials data base for selected vanadium-base alloys, and a comparison of projected performance characteristics compared to other candidate alloys. Also, critical research and development (R and D) needs are defined

  3. Progress in ODS Alloys: A Synopsis of a 2010 Workshop on Fe- Based ODS Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kad, Bimal [University of California, San Diego; Dryepondt, Sebastien N [ORNL; Jones, Andy R. [University of Liverpool; Vito, Cedro III [National Energy Technology Laboratory (NETL); Tatlock, Gordon J [ORNL; Pint, Bruce A [ORNL; Tortorelli, Peter F [ORNL; Rawls, Patricia A. [National Energy Technology Laboratory (NETL)

    2012-01-01

    In Fall 2010, a workshop on the role and future of Fe-based Oxide Dispersion Strengthened (ODS) alloys gathered together ODS alloy suppliers, potential industrial end-users, and technical experts in relevant areas. Presentations and discussions focused on the current state of development of these alloys, their availability from commercial suppliers, past major evaluations of ODS alloy components in fossil and nuclear energy applications, and the technical and economic issues attendant to commercial use of ODS alloys. Significant progress has been achieved in joining ODS alloys, with creep resistant joints successfully made by inertia welding, friction stir welding and plasma-assisted pulse diffusion bonding, and in improving models for the prediction of lifetime components. New powder and alloy fabrication methods to lower cost or improve endproduct properties were also described. The final open discussion centered on challenges and pathways for further development and large-scale use of ODS alloys.

  4. Discontinuous precipitation in copper base alloys

    Indian Academy of Sciences (India)

    K T Kashyap

    2009-08-01

    Discontinuous precipitation (DP) is associated with grain boundary migration in the wake of which alternate plates of the precipitate and the depleted matrix form. Some copper base alloys show DP while others do not. In this paper the misfit strain parameter, , has been calculated and predicted that if 100 > ± 0.1, DP is observed. This criterion points to diffusional coherency strain theory to be the operative mechanism for DP.

  5. Effects of alloying side B on Ti-based AB2 hydrogen storage alloys

    Institute of Scientific and Technical Information of China (English)

    王家淳; 于荣海; 刘庆

    2004-01-01

    Ti-based AB2-type hydrogen storage alloys are a group of promising materials, which will probably replace the prevalent rare earth-based AB5-type alloys and be adopted as the main cathode materials of nickelmetal hydride (Ni-MH) batteries in the near future. Alloying in side B is a major way to improve the performance of Ti-based AB2-type alloys. Based on recent studies, the effects of alloying elements in side B upon the performance of Ti-based AB2 -type hydrogen storage alloys are systematically reviewed here. These performances are divided into two categories, namely PCI characteristics, including hydrogen storage capacity (HSC), plateau pressure (PP), pressure hysteresis (PH) and pressure plateau sloping (PPS) , and electrochemical properties, including discharge capacity (DC), activation property (AP), cycling stability (CS) and high-rate dischargeability (HRD). Furthermore, the existing problems in these investigations and some suggestions for future research are proposed.

  6. Low-voltage antimony-doped SnO2 nanowire transparent transistors gated by microporous SiO2-based proton conductors

    Institute of Scientific and Technical Information of China (English)

    Xuan Rui-Jie; Liu Hui-Xuan

    2012-01-01

    A battery drivable low-voltage transparent lightly antimony(Sb)-doped SnO2 nanowire electric-double-layer (EDL)field-effect transistor (FET) is fabricated on an ITO glass substrate at room temperature.An ultralow operation voltage of 1 V is obtained on account of an untralarge specific gate capacitance (~ 2.14 μF/cm2) directly bound up with mobile ions-induced EDL (sandwiched between the top and bottom electrodes) effect.The transparent FET shows excellent electric characteristics with a field-effect mobility of 54.43 cm2/V.s,current on/off ration of 2 × 104,and subthreshold gate voltage swing (S =dVgs/d(logIds)) of 140 mV/decade.The threshold voltage Vth (0.1 V) is estimated which indicates that the SnO2 namowire transistor operates in an n-type enhanced mode.Such a low-voltage transparent nanowire transistor gated by a microporous SiO2-based solid electrolyte is very promising for battery-powered portable nanoscale sensors.

  7. Characterization of copper base alloys obtained by mechanical alloying

    International Nuclear Information System (INIS)

    The micro and nano structure of mechanical alloys of Cu-Al, Cu-V and Cu-Ti obtained by reactive milling, using an Attritor mill, was analyzed by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscope (TEM). In order to study the evolution of the alloys during the manufacturing process and during the period of service, the DSC and XRD were done before the mechanical milling, after 30 hours of milling and after hot extrusion of the alloyed powders. Using the Williamson-Hall and Klug-Alexander methods the size of the crystallites and the density of the dislocations in the prepared alloys were evaluated. In all the milled powder cases, the grain and crystallite size was found to be nanometric, the dispersoids were also nanometric and there was texture in the copper planes (220), in the cases of the milled Cu- Ti and Cu-V powders (au)

  8. Changes induced by gamma radiation in nanocomposites based on copper II and antimony sulfides in commercial poly(methyl methacrylate) matrix

    International Nuclear Information System (INIS)

    Poly (methyl methacrylate) (PMMA) is a polymer with wide application in the manufacture of medical devices that is exposed to gamma irradiation. Currently the use of composite materials has been disseminated and PMMA is an excellent polymer matrix to package various materials. This study aimed to analyze the changes induced by gamma irradiation (25 kGy) on the properties of PMMA nanocomposites with nanoparticles of copper II sulfide (250nm-900nm) and antimony sulfite (300-500 nm). The nanoparticles were added to the polymer in different concentrations and synthesized by ultrasonic irradiation from the corresponding chlorides with thioacetamide. Viscometric results showed a good radioprotective effect of nanoparticles of copper and antimony. It was found a good protection of nanoparticles on PMMA matrix in the concentration of 0.3% wt. The protections of 75% and 50% were calculated for nanoparticles of antimony and copper II, respectively. (author)

  9. 断续流动原子荧光法测定铅锡合金中的痕量锑%Determination of Trace Amount of Antimony in Lead-tin Alloy by Intermittent Flow Atomic Fluorescence Spectrometry

    Institute of Scientific and Technical Information of China (English)

    马毅红; 尹艺青; 陈玉珍

    2012-01-01

    目的:建立氢化物发生双道原子荧光法测定铅锡合金中锑含量的方法,为测定铅锡合金中锑提供依据。方法:选择了最佳的仪器条件,进行样品处理方法、KBH4浓度、检出限、回收率等研究。结果:本方法的标准曲线方程y=157.56x-2.3962,相关系数γ=0.9999,线性范围为0~40μg/L,精密度为1.3%,检出限为0.0304μg/L,回收率达115%。结论:本方法操作简单、快速、灵敏度高、干扰少,可获得满意的结果。%Purpose: A analytical method is recommended for determination of Trace Amount of Antimony in Lead-Tin Alloy by hydride generation double channel atomic fluorescence spectrometry,which provides basis for its measurement.Methods: Optimum condition for the instrument determination is applied to conduct researches relating to the method of sampling,concentration of KBH4,detection limits and recovery rate.Results: The standard curve of the linear equation was y=157.56x-2.3962 with correlation coefficient γ = 0.9999 and linear range of 0~40 μg/L.The precision and the detection limits were 1.3 % and 0.0304 μg/L respectively while the returns-ratio achieves 115 %.Conclusion: The method is easy,fast,highly sensitive and with no much interference during the operation,which can lead to satisfactory results.

  10. Ti-V-Mn based alloys for hydrogen compression system

    Energy Technology Data Exchange (ETDEWEB)

    Dehouche, Z. [Institut de Recherche sur l' hydrogene, Universite du Quebec a Trois-Rivieres, C.P. 500, Trois-Rivieres, Que., G9A 5H7 (Canada)]. E-mail: zahir_dehouche@uqtr.ca; Savard, M. [Institut de Recherche sur l' hydrogene, Universite du Quebec a Trois-Rivieres, C.P. 500, Trois-Rivieres, Que., G9A 5H7 (Canada); Laurencelle, F. [Institut de Recherche sur l' hydrogene, Universite du Quebec a Trois-Rivieres, C.P. 500, Trois-Rivieres, Que., G9A 5H7 (Canada); Goyette, J. [Institut de Recherche sur l' hydrogene, Universite du Quebec a Trois-Rivieres, C.P. 500, Trois-Rivieres, Que., G9A 5H7 (Canada)

    2005-09-01

    Ti-V-Mn based hydrides are one family of alloys with improved hydrogenation properties and they have a great potential to replace the AB{sub 5} alloys as the sorption materials in hydrogen compression systems, although there still are many problems associated with their use, including unstable reversible hydrogen capacity and unfavorable thermodynamic properties. To gain a better understanding on the effect of the substitution elements and to optimize the alloy composition for high storage capacity, the influence of the alloy stoichiometry was investigated. Ti-Zr-V-Mn alloys were prepared by arc melting technique and were annealed in vacuum at temperature above 900 deg. C to obtain great sorption properties. Hydrogen absorption and desorption kinetics and PCT characteristics of these alloys at ambient temperature were measured and compared. These hydrogen storage features were also discussed in relation to the effect of alloy element compositions. Ti-Zr-V-Mn alloy cycling behavior was also examined.

  11. Ti-V-Mn based alloys for hydrogen compression system

    International Nuclear Information System (INIS)

    Ti-V-Mn based hydrides are one family of alloys with improved hydrogenation properties and they have a great potential to replace the AB5 alloys as the sorption materials in hydrogen compression systems, although there still are many problems associated with their use, including unstable reversible hydrogen capacity and unfavorable thermodynamic properties. To gain a better understanding on the effect of the substitution elements and to optimize the alloy composition for high storage capacity, the influence of the alloy stoichiometry was investigated. Ti-Zr-V-Mn alloys were prepared by arc melting technique and were annealed in vacuum at temperature above 900 deg. C to obtain great sorption properties. Hydrogen absorption and desorption kinetics and PCT characteristics of these alloys at ambient temperature were measured and compared. These hydrogen storage features were also discussed in relation to the effect of alloy element compositions. Ti-Zr-V-Mn alloy cycling behavior was also examined

  12. Pentavalent Antimonials: New Perspectives for Old Drugs

    OpenAIRE

    Ribeiro, Raul R.; Cynthia Demicheli; Frédéric Frézard

    2009-01-01

    Pentavalent antimonials, including meglumine antimoniate and sodium stibogluconate, have been used for more than half a century in the therapy of the parasitic disease leishmaniasis. Even though antimonials are still the first-line drugs, they exhibit several limitations, including severe side effects, the need for daily parenteral administration and drug resistance. The molecular structure of antimonials, their metabolism and mechanism of action are still being investigated. Some recent stud...

  13. Microstructures of nickel-base alloy dissimilar metal welds

    OpenAIRE

    Mouginot, Roman; Hänninen, Hannu

    2013-01-01

    Dissimilar metal welds (DMWs) between low-alloy steels (LAS), stainless steels (SS) and nickel-base alloys are very important in the design of conventional and nuclear power plants (NPPs). They help to reach better performances for high temperature environment but they can promote premature failure of components. Failure is often related to cracking in the heat affected zone of base materials. In this study, a literature review was conducted concerning the behavior of Inconel Ni-base alloy...

  14. Recent advances on antimony(III/V) compounds with potential activity against tumor cells.

    Science.gov (United States)

    Hadjikakou, S K; Ozturk, I I; Banti, C N; Kourkoumelis, N; Hadjiliadis, N

    2015-12-01

    Antimony one of the heavier pnictogens, has been in medical use against microbes and parasites as well. Antimony-based drugs have been prescribed against leishmaniasis since the parasitic transmission of the tropical disease was understood in the beginning of the 20th century. The activity of arsenic against visceral leishmaniasis led to the synthesis of an array of arsenic-containing parasitic agents, among them the less toxic pentavalent antimonials: Stibosan, Neostibosan, and Ureastibamine. Other antimony drugs followed: sodium stibogluconate (Pentostam) and melglumine antimoniate (Glucantim or Glucantime); both continue to be in use today despite their toxic side effects and increasing loss in potency due to the growing resistance of the parasite against antimony. Antimony compounds and their therapeutic potentials are under consideration from many research groups, while a number of early reviews recording advances of antimony biomedical applications are also available. However, there are only few reports on the screening for antitumor potential of antimony compounds. This review focuses upon results obtained on the anti-proliferative activity of antimony compounds in the past years. This survey shows that antimony(III/V) complexes containing various types of ligands such as thiones, thiosemicarbazones, dithiocarbamates, carboxylic acids, or ketones, nitrogen donor ligands, exhibit selectivity against a variety of cancer cells. The role of the ligand type of the complex is elucidated within this review. The complexes and their biological activity are already reported elsewhere. However quantitative structure-activity relationship (QSAR) modeling studies have been carried out and they are reported for the first time here. PMID:26092367

  15. Indentation toughness of Mo5Si3-based alloys

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The indentation toughness of Mo5Si3 -based phases was studied with regard to different alloying elements, amount of alloying addition as well as the presence of secondary phases. Cr, Ti, Nb, Ni and Co were added as alloying elements. The results show that the indentation fracture toughness of Mo5Si3 increases with the alloying additions, from 2.4 Mpa *m1/2 for mon olithic to just over 3 Mpa*m1/2 for highly alloyed Mo5Si3. Small volume fractions of brittle secondary phases may have a positive impact on the inde ntation toughness; while larger fractions seems to lower the toughness.

  16. Antimony Doped Tin Oxide Thin Films: Co Gas Sensor

    Directory of Open Access Journals (Sweden)

    P.S. Joshi

    2011-01-01

    Full Text Available Tin dioxide (SnO2 serves as an important base material in a variety of resistive type gas sensors. The widespread applicability of this semicoducting oxide is related both to its range of conductance variability and to the fact that it responds to both oxidising and reducing gases. The antimony doped tin-oxide films were prepared by spray pyrolysis method. The as-deposited films are blackish in colour. Addition of antimony impurity showed little increase in the thickness. The X-ray diffraction pattern shows characteristic tin oxide peaks with tetragonal structure. As the doping concentration of antimony was increased, new peak corresponding to Sb was observed. The intensity of this peak found to be increased when the Sb concentration was increased from 0.01 % to the 1 % which indicates the antimony was incorporated into the tin oxide. For gas sensing studies ohmic contacts were preferred to ensure the changes in resistance of sensor is due to only adsorption of gas molecule. The graph of I-V shows a straight line in nature which indicates the ohmic contact. The sensitivity of the sensor for CO gas was tested. The sensitivity of antimony doped tin oxide found to be increased with increasing Sb concentration. The maximum sensitivity was observed for Sb = 1 % at a working temperature of 250 °C.

  17. Antimony (Sb) and lead (Pb) in contaminated shooting range soils: Sb and Pb mobility and immobilization by iron based sorbents, a field study.

    Science.gov (United States)

    Okkenhaug, Gudny; Grasshorn Gebhardt, Karl-Alexander; Amstaetter, Katja; Lassen Bue, Helga; Herzel, Hannes; Mariussen, Espen; Rossebø Almås, Åsgeir; Cornelissen, Gerard; Breedveld, Gijs D; Rasmussen, Grete; Mulder, Jan

    2016-04-15

    Small-arm shooting ranges often receive a significant input of lead (Pb), copper (Cu) and antimony (Sb) from ammunition. The goal of the present study was to investigate the mobility, distribution and speciation of Pb and Sb pollution under field conditions in both untreated and sorbent-amended shooting range soil. Elevated Sb (19-349μgL(-1)) and Pb (7-1495μgPbL(-1)) concentrations in the porewater of untreated soil over the four-year test period indicated a long-term Sb and Pb source to the adjacent environment in the absence of remedial measures. Mixing ferric oxyhydroxide powder (CFH-12) (2%) together with limestone (1%) into the soil resulted in an average decrease of Sb and Pb porewater concentrations of 66% and 97%, respectively. A similar reduction was achieved by adding 2% zerovalent iron (Fe°) to the soil. The remediation effect was stable over the four-year experimental period indicating no remobilization. Water- and 1M NH4NO3-extractable levels of Sb and Pb in field soil samples indicated significant immobilization by both treatments (89-90% for Sb and 89-99% for Pb). Results from sequential extraction analysis indicate fixation of Sb and Pb in less accessible fractions like amorphous iron oxides or even more crystalline and residual mineral phases, respectively. This work shows that amendment with Fe-based sorbents can be an effective method to reduce the mobility of metals both in cationic and anionic form in polluted shooting range soil. PMID:26799225

  18. 流动注射在线离子交换分离富集-氢化物发生原子荧光光谱法测定铜合金中痕量锑%Determination of trace antimony in copper alloys by flow injection on-line ion-exchange separation and enrichment-hydride generation atomic fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    吴良俊; 邱海鸥; 郝志红; 袁红战; 郑洪涛

    2009-01-01

    A method for the determination of trace antimony in copper by flow injection on-line ion-exchange separation and enrichment-hydride generation atomic fluorescence spectrometry is suggested. The manifolds and operating program for ftlow injection on-line ion-exchange were designed and chemical conditions were optimized. Antimony complex was absorbed on strongly basic anion exchange resin 717 with 1. 4 mol/L HC1 as absorbent medium and 2. 0 mol/L HNO_3 for elution. The interference of co-existent elements (i-ron, nickel, lead, etc) was eliminated while antimony was enriched and was determined by hydride generation-atomic fluorescence spectrometry. The method is easy to operate and fast, and has lesser pollution to environment. The linear range is 0. 2-120μg/L and the RSD is 3%~5% with detection limit of 0. 05 μg/L. The results for determination of antimony in standard samples of copper alloys are satisfactory.%提出了流动注射离子交换在线分离富集-氢化物发生原子荧光光谱法测定铜合金中痕量锑的分析方法.设计了流动注射在线离子交换的流路和操作程序,优化了各项化学条件.采用717强碱性阴离子交换树脂吸附锑,并能有效消除铁、镍、铅等元素的干扰,也使大量基体元素铜与待测元素分离,锑在1.4 mol/L的HCl介质中上柱,选用2.0 mol/L的HNO_3作为洗脱剂.实现了氢化物发生原子荧光光谱法对铜合金中痕量锑的在线测定.方法操作简便、快速,环境污染小,线性范围为0.15~120 μg/L,相对标准偏差在3%~5%之间,检出限为0.05μg/L.方法应用于铜合金标准样品,结果与推荐值吻合.

  19. Stress corrosion crack tip microstructure in nickel-based alloys

    International Nuclear Information System (INIS)

    Stress corrosion cracking behavior of several nickel-base alloys in high temperature caustic environments has been evaluated. The crack tip and fracture surfaces were examined using Auger/ESCA and Analytical Electron Microscopy (AEM) to determine the near crack tip microstructure and microchemistry. Results showed formation of chromium-rich oxides at or near the crack tip and nickel-rich de-alloying layers away from the crack tip. The stress corrosion resistance of different nickel-base alloys in caustic may be explained by the preferential oxidation and dissolution of different alloying elements at the crack tip. Alloy 600 (UNS N06600) shows good general corrosion and intergranular attack resistance in caustic because of its high nickel content. Thermally treated Alloy 690 (UNS N06690) and Alloy 600 provide good stress corrosion cracking resistance because of high chromium contents along grain boundaries. Alloy 625 (UNS N06625) does not show as good stress corrosion cracking resistance as Alloy 690 or Alloy 600 because of its high molybdenum content

  20. Thermal sprayed iron base alloys coatings

    International Nuclear Information System (INIS)

    Particularities of thermal spraying of iron-based alloys coatings are associated with sufficiently great values of parameter of melting difficulty (for Fe D = 2.08 I-10/sup 10/ kJ.kg/sup -1/.m/sup -3/), and relatively low values of coefficients-of heat accumulation (for Fe b=C.raw.Lambda /sub 0.5/=108 W.m/sup -2/.K.sec/sup-0.5/). These materials are less inclined to form quality coating under the influence of the thermal activation and therefore it is reasonable to use in addition the mechanical activation of substrate surface. The powder of iron-base alloy FeSi/sub 7/AI/sub 3.5/C/sub 2/ was obtained by melt-atomization with water hardening of droplets. The main phase components of powder are alpha and gamma -solid solution on base of Fe (austenite), cementite (Fe/sub 3/C), metastable rhombic lattice x-phase, and possibly metastable carbide Fe/sub 2/C. When the powder particles shape is oval which axis dimensions about 80 and 300 micro meter, the main phase components of detonation sprayed coatings in case of oxy-acetylene gas mixture are alpha and gamma -phases, in case of oxy-propane-butane mixture the coating phase component the same as initial powder. When the powder particles size is 63-100 micro meter, the coatings phase components are alpha and gamma - solid solutions, Fe/sub 3/C, x-phase, Fe/sub 2/C, Fe/sub 3/0/sub 4/ and FeO. The main phase components of FeSi/sub 7/B/sub 12,6/ powder are alpha-solid solution, borides Fe/sub 2/B and FeB, X- phase. The sprayed coatings have the same phase composition. These types of Fe-base alloys powders have relatively low cost, easy available and can used for deposition of wear resistant coatings. (author)

  1. ATOM PROBE STUDY OF TITANIUM BASE ALLOYS : PRELIMINARY RESULTS

    OpenAIRE

    Menand, A.; Chambreland, S.; Martin, C

    1986-01-01

    Two different titanium base alloys, Ti46 Al54 and Ti88.8 Cu2.3, Al8.9, have been studied by atom probe microanalysis. A precipitate of Ti2 Al was analysed in the binary alloys. Micro-analysis of Ti Cu Al alloy revealed the presence of Copper enriched zones. The study has also exhibited a penetration of Hydrogen in the samples, probably due to preparation technique. The results demonstrate the feasibility of studies on titanium base alloys by mean of atom probe.

  2. Vortex-assisted surfactant-enhanced emulsification microextraction based on solidification of floating organic drop followed by electrothermal atomic absorption spectrometry for speciation of antimony (ΙΙΙ, V).

    Science.gov (United States)

    Eftekhari, Mohammad; Chamsaz, Mahmoud; Arbab-Zavar, Mohammad Hossein; Eftekhari, Ali

    2015-01-01

    Vortex-assisted surfactant-enhanced emulsification microextraction based on solidification of floating organic drop (VASEME-SFO) was used for preconcentration and speciation of antimony (ΙΙΙ, V) followed by electrothermal atomic absorption spectrometry (ETAAS). In this procedure, Triton X-114 was used as emulsifier and 1-undecanol was used as extraction solvent. This method is based on the complexation of Sb(ΙΙΙ) with dithizone (as complexing agent) at pH 2 and extraction of the resulting hydrophobic complex into the extraction solvent (1-undecanol) with vortex-assisted liquid phase microextraction, whereas Sb(V) remained in solution. Sb(ΙΙΙ) in extraction solvent was directly analyzed by ETAAS after dilution with ethanol, and Sb(V) was calculated by subtracting Sb(ΙΙΙ) from the total antimony after reducing Sb(V) to Sb(ΙΙΙ) by L-cysteine. Under the optimized condition, the calibration curve was linear in the range of 0.4-8 μg L(-1) of Sb(ΙΙΙ) with a correlation coefficient of 0.9995. The detection limit based on three times of the standard deviation of the blank (n = 8) was 0.09 μg L(-1). The validation and the recovery of the proposed method were performed by the analysis of a certified reference material and spike method. The obtained results were in very good agreements with certified values. The proposed method was successfully applied for the determination of antimony species at trace levels in different water samples. PMID:25404541

  3. Hot rolling of intermetallics FeAl phase based alloys

    OpenAIRE

    G. Niewielski; D. Kuc; Schindler, I.; I. Bednarczyk

    2008-01-01

    Purpose: The one of major problem restricting universal employment of intermetallic phase base alloy istheir low plasticity which leads to hampering their development as construction materials. The following workconcentrates on possibilities to form through rolling process the alloys with various aluminium content.Design/methodology/approach: After casting and annealing, alloy specimens were subjected to axialsymmetriccompression at temperatures ranging from 900 to 1200°C at 10 s-1 strain rat...

  4. Combined effect of strontium modifier and antimony refiner on texture and growth mode of eutectic phase in an Al-11Si-2Cu-0.8Zn-0.6Fe cast alloy

    Science.gov (United States)

    Farahany, Saeed; Ourdjini, Ali; Hekmat-Ardakan, Alireza

    2015-12-01

    Results of electron back-scattered diffraction and transmission electron microscopy studies reveal that the orientation of aluminium in the eutectic phase is different from the surrounding aluminium dendrites and that twin spacing of eutectic silicon increased significantly due to the interaction between strontium and antimony. In addition, the formation of ternary Mg2Sb2Sr intermetallic compound that precedes the eutectic reaction was proposed to be responsible for interaction.

  5. HIGH CYCLE FATIGUE PROPERTIES OF NICKEL-BASE ALLOY 718

    Institute of Scientific and Technical Information of China (English)

    K.Kobayashi; K.Yamaguchi; M.Hayakawa; M.Kimura

    2004-01-01

    The fatigue properties of nickel-base Alloy 718 with fine- and grain-coarse grains were investigated. In the fine-grain alloy, the fatigue strength normalized by the tensile strengtn was 0.51 at 107 cycles. In contrast, the fatigue strength of the coarse-grain alloy was 0.32 at the same cycles, although the fatigue strengths in the range from 103to 105 cycles are the same for both alloys. The fracture appearances fatigued at around 106 cycles showed internal fractures originating from the flat facets of austenite grains for both alloys. The difference in fatigue strength at 107 cycles between the fine- and coarse-grain alloys could be explained in terms of the sizes of the facets from which the fractures originated.

  6. Excessively High Vapor Pressure of Al-based Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Jae Im Jeong

    2015-10-01

    Full Text Available Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass-forming ability. The vapor pressure of the amorphous alloys around 573 K was close to the vapor pressure of crystalline Al near its melting temperature, 873 K. Our results strongly suggest the possibility of fabricating nanocrystallites or thin films by evaporation at low temperatures.

  7. LASER CLADDING WITH COBALT-BASED HARDFACING ALLOYS

    OpenAIRE

    Frenk, A.; WagniÈre, J.-D.

    1991-01-01

    Preliminary results aimed at designing Co-based hardfacing alloys specifically for the laser cladding process are reported. Three alloys, ranging from hypo- to hypereutectic were deposited using scanning velocities between 1.7 and 170 mm/s. The microstructures and the dry sliding wear resistances of the clads were investigated. First trends relating composition to dry sliding wear resistance were deduced.

  8. Corrosion resistance improvement of titanium base alloys

    Directory of Open Access Journals (Sweden)

    Mihai V. Popa

    2010-01-01

    Full Text Available The corrosion resistance of the new Ti-6Al-4V-1Zr alloy in comparison with ternary Ti-6Al-4V alloy in Ringer-Brown solution and artificial Carter-Brugirard saliva of different pH values was studied. In Ringer-Brown solution, the new alloy presented an improvement of all electrochemical parameters due to the alloying with Zr; also, impedance spectra revealed better protective properties of its passive layer. In Carter-Brugirard artificial saliva, an increase of the passive film thickness was proved. Fluoride ions had a slight negative influence on the corrosion and ion release rates, without to affect the very good stability of the new Ti-6Al-4V-1Zr alloy.

  9. Fabrication and characterization of niobium based Fe-Cr alloys via mechanical alloying

    International Nuclear Information System (INIS)

    Niobium (Nb) based alloys and composites are currently used in various high temperature applications such as rocket engine nozzles, superconducting magnets, and automotive structural components. Niobium has also been traditionally employed as a micro-alloying element to fabricate high strength, low alloy steels and nickel based superalloys (example: Inconel 718) on account of its ability to form nano dispersions/precipitates which effectively impede high temperature grain growth. Traditionally, niobium alloys such as C-103 (Nb-10Hf-1Ti) and FS-85 (Nb-10W-28Ta-1Zr) having excellent high temperature properties have been fabricated using arc melting and e-beam melting methods. However these alloys have not been widely used on account of their high fabrication costs. On the other hand, nanostructured steels such as oxide dispersion strengthened (ODS) alloys (example: 12Y1, 12YWT, FeCrAl, HT-9, Hestalloy etc) are being proposed for high temperature structural applications for new generation nuclear reactors. In this context we present some of the work related to fabrication and characterization of some known ODS steel compositions with Nb as a micro-alloying element that is currently underway at the High Temperature Materials Laboratory at Virginia Commonwealth University in context of high temperature nuclear applications. (author)

  10. Processing TiAl-Based Alloy by Elemental Powder Metallurgy

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    TiAl-based alloys with various compositions (including Ti-48Al, Ti-47Al-2Cr-2Nb, Ti-47Al-2Cr-2Nb-0.2B and Ti-47Al-3Cr, in mole fraction) had been prepared by elemental powder metallurgy (EPM). The results have shown that the density of the prepared Ti-48Al alloy increases with increasing hot pressing temperature up to 1300℃. The Ti-48Al alloy microstructure mainly consisted of island-like Ti3Al phase and TiAl matrix at hot pressing temperature below 1300℃, however, coarse α2/γlamellar colonies and γ grains appeared at 1400℃. It has also indicated that the additions of elemental Cr and B can refine the alloy microstructure. The main microstructural inhomogeneity in EPM TiAl-based alloys was the island-like α2 phase or the aggregate of α2/γ lamellar colony, and such island-like structure will be inherited during subsequent heat treatment in (α+γ) field. Only after heat treatment in α field would this structure be eliminated. The mechanical properties of EPM TiAl-based alloys with various compositions were tested, and the effect of alloy elements on the mechanical properties was closely related to that of alloy elements on the alloy microstructures. Based on the above results, TiAl-based alloy exhaust valves were fabricated by elemental powder metallurgy and diffusion joining. The automobile engine test had demonstrated that the performance of the manufactured valves was very promising for engine service.

  11. Stress corrosion cracking of nickel-base alloy weldments

    International Nuclear Information System (INIS)

    Stress corrosion cracking (SCC) of weldments occurs in media such as chloride, hydrofluoric acid, polythionic acid, caustic soda and molten metals. Nickel-base alloys on account of their low SCC are preferred for weldments in the above media. However, the choice of a particular nickel-base alloy depends upon the condition in which they are used. Studies on this aspect are reviewed. In reprocessing plants, Ni-Cr-Mo alloy No6625 and No6455 are found suitable. The Ni-Cr alloy No6600 failed in BWR type reactor due intergranular SCC. The alloy No6690 which has a higher chromium content is immune to intergranular SCC. Reduction of free carbon in the matrix of the weld metal makes it resistant to intergranular SCC. (M.G.B.)

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

    DEFF Research Database (Denmark)

    Leisner, P.; Benzon, M. E.; Christoffersen, Lasse; Panagopoulos, C. N.; Papachristos, V. D.; Katsikis, S.

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

  13. Design of a Flow-Through Voltammetric Sensor Based on an Antimony-Modified Silver Electrode for Determining Lithol Rubine B in Cosmetics

    OpenAIRE

    Wang Lai-Hao; Huang Shu-Juan

    2011-01-01

    Lithol Rubine B (LRB; the disodium salt of 3-hydroxy-4-[(4-methyl-2-sulfophenyl) azo]-2-naphthalenecarboxylic acid) was detected using high-performance liquid chromatography with an electrochemical (antimony film on silver) detector (HPLC-ECD). For direct current (DC) mode, with the current at a constant potential, and measurements with suitable experimental parameters, a linear concentration from 0.125 to 1.80 μg/mL was found. The detection limit of our method was approximately 2.0 ng/mL. An...

  14. Cr{sub 2}Nb-based alloy development

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.T.; Tortorelli, P.F.; Horton, J.A. [Oak Ridge National Lab., TN (United States)] [and others

    1996-08-01

    Alloys of Cr-Cr{sub 2}Nb with exceptionally high strength at 1200{degrees}C have been developed. However, these compositions suffer from limited ductility and toughness at room temperature. Despite improvements from processing modifications, as-fabricated defects still limit room temperature mechanical behavior. In contrast, an alloy system with only a small mismatch of the coefficients of thermal expansion of the two phases, Cr-Cr{sub 2}Zr, showed good fabricability. However, these alloys are weaker than Cr-Cr{sub 2}Nb compositions at high temperatures and have poor oxidation resistance. Silicide coatings can provide high-temperature oxidation and sulfidation protection of these alloys. Improvements in room temperature mechanical properties of Laves-phase-strengthened alloys will rely on further development based on increasing the ductility of the matrix phase by impurity control and compositional modifications.

  15. Antimony powder-modified carbon paste electrodes for electrochemical stripping determination of trace heavy metals

    International Nuclear Information System (INIS)

    Highlights: → New antimony powder-modified carbon paste electrode. → Combination of specific properties of carbon paste substrate and metallic antimony. → No requirement of using toxic antimony(III) salts. → Electrochemical stripping determination of trace heavy metals at ppb levels. → Anodic stripping voltammetric and stripping chronopotentiometric measurements. - Abstract: A new type of the antimony electrode based on a carbon paste bulk-modified with antimony powder (Sb-CPE) is presented for the determination of cadmium(II) and lead(II) ions at the microgram-per-liter concentration level, when using square-wave anodic stripping voltammetric or stripping chronopotentiometric protocol. The Sb-CPE was prepared by mixing fine antimony powder, carbon powder, and silicon oil, thus combining typical features of the carbon paste material with specific electrochemical properties of antimony. Key-operational parameters, including the amount of antimony powder in the carbon paste mixture, effect of the deposition potential and deposition time, were optimized and electroanalytical performance of the Sb-CPE in nondeaerated solution of 0.01 M hydrochloric acid (pH 2) was compared with related bismuth powder-modified carbon paste electrode (Bi-CPE) and with in situ prepared antimony film carbon paste electrode (SbF-CPE). The electrode of interest exhibited well-developed signals and highly linear calibration plots for both metal ions tested. In addition, favorable limits of detection were achieved; namely: 1.4 μg L-1 for Cd(II) and 0.9 μg L-1 for Pb(II). The applicability of the new electrode was demonstrated on the analysis of tap water (spiked sample). Besides voltammetric measurements, the Sb-CPE was preliminary tested also under chronopotentiometric stripping mode in deoxygenated solutions, revealing also an excellent electroanalytical performance.

  16. On the mechanical properties of TiNb based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Y. [SIMAP-CNRS, Institut Polytechnique de Grenoble, BP 75, St. Martin d’Hères 38402 (France); Georgarakis, K. [WPI Advanced Institute for Materials Research, Tohoku University, Sendai (Japan); SIMAP-CNRS, Institut Polytechnique de Grenoble, BP 75, St. Martin d’Hères 38402 (France); Yokoyama, Y. [WPI Advanced Institute for Materials Research, Tohoku University, Sendai (Japan); Yavari, A.R., E-mail: euronano@minatec.inpg.fr [SIMAP-CNRS, Institut Polytechnique de Grenoble, BP 75, St. Martin d’Hères 38402 (France)

    2013-09-15

    Highlights: •Systematic study of compressive behaviors of TiNb based alloys in different states. •Comparison between X-ray diffraction results in reflection and transmission mode. •High melting temperature TiNb based alloys were fabricated by copper mold casting. •Textures of studied alloys are analyzed through synchrotron radiation data. -- Abstract: A series of TiNb(Sn) alloys were synthesized by copper mold suction casting and subjected to different heat treatments (furnace cooling or water quenching). The microstructure, thermal and mechanical properties of the as-cast and heat treated samples were investigated. For the Ti–8.34 at.% Nb alloy, the as-cast and water quenched samples possess martensitic α′′ phase at room temperature and compression tests of these samples show occurrence of shape memory effect. For β phase Ti–25.57 at.% Nb alloys, stress-induced martensitic transformation was found during compression in the as-cast and water quenched samples. For the ternary Ti–25.05 at.%Nb–2.04 at.%Sn alloy, conventional linear elastic behavior was observed. It is shown that the addition of Sn increases the stability of the β phase. The Young’s moduli of these alloys were also measured by ultrasonic measurements. Water-quenched Ti–25.57 at.%Nb alloy was found to exhibit the lowest Young’s modulus value. Sn addition has small impact on the Young’s moduli of the TiNb alloys.

  17. Development of Mg-based Hydrogen Storage Alloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Mg-based hydrogen storage alloys are considered as a promising candidate for hydrogen system because of its lightweight, high storage capacity, low price and rich mineral resources. In detail,we reviewed the preparation and properties of Mg-Ni-based hydrogen storage alloys. All kinds of attempts have been done to improve the hydriding and dehydriding behaviors. It is found that the partial substitution of foreign elements can decrease the hydrogen absorption temperature,especially the substitution of a more electronegative element, such as Al and Mn. Mechanical alloying (MA) and mechanical grinding (MG) are the most effective methods to improve the hydriding/dehydriding kinetics and electrochemical capacity, and decrease the desorption temperature, but the corrosion resistance is so poor that the 80% of maximum capacity is lost within ten cycles. Microencapsulation is a useful measurement for improving the corrosion resistance and electrocatalytic activity. In order to improve the properties of the alloys for practical application, the alloys should have a large number of defects, which give activated sites, subsequently,MA, MG and electroless plating should be used to improve the hydriding/dehydriding kinetics and protect the surface of alloys, respectively. The new composite Mg-based alloys give a new way for the hydrogen storage material to practical application. Furthermore we put forward several problems which will be discussed in future.

  18. Nonlinear Hamiltonian modelling of magnetic shape memory alloy based actuators.

    OpenAIRE

    Gauthier, Jean-Yves; Hubert, Arnaud; Abadie, Joël; Chaillet, Nicolas; Lexcellent, Christian

    2008-01-01

    This paper proposes an application of the Lagrangian formalism and its Hamiltonian extension to design, model and control a mechatronic system using Magnetic Shape Memory Alloys. In this aim, an original dynamical modelling of a Magnetic Shape Memory Alloy based actuator is presented. Energy-based techniques are used to obtain a coherent modelling of the magnetical, mechanical and thermodynamic phenomena. The Lagrangian formalism, well suited in such a case, is introduced and used to take int...

  19. Martensite transformation in antimony implanted stainless steel

    International Nuclear Information System (INIS)

    The authors have used Rutherford backscattering analysis (RBS) and transmission electron microscopy (TEM) and diffraction to investigate austenitic stainless steel crystals implanted at room temperature with 80 keV Sb+ ions to a fluence of 5 x 1020 ions/m2, thus providing implantation with a heavy group V element. RBS channeling spectra from implanted crystals show a damage peak which approaches the height of the random level and therefore indicates a very high degree of disorder in the implanted layers. The distribution of the disorder extends to a depth 3-5 times the depth of the primary radiation damage. The Sb peaks under channeling as well as random conditions are indistinguishable, confirming that substitutionality during implantation is negligible. To establish the nature of the disorder which cannot be assessed from the RBS analysis alone, and in particular to assess whether an amorphous alloy is formed in the implanted layer as indicated from the RBS spectra, samples implanted under similar conditions were investigated in the TEM. Significant extra spots in the patterns can be ascribed to the presence of a radiation induced b.c.c. phase of martensitic origin. The result that a significant amount of martensite can be induced by antimony implantation seems to indicate that the main driving force for the transition is due to damage induced stress concentrations. (Auth.)

  20. Coordination- and Redox-Noninnocent Behavior of Ambiphilic Ligands Containing Antimony.

    Science.gov (United States)

    Jones, J Stuart; Gabbaï, François P

    2016-05-17

    Stimulated by applications in catalysis, the chemistry of ambiphilic ligands featuring both donor and acceptor functionalities has experienced substantial growth in the past several years. The unique opportunities in catalysis offered by ambiphilic ligands stem from the ability of their acceptor functionalities to play key roles via metal-ligand cooperation or modulation of the reactivity of the metal center. Ligands featuring group 13 centers, most notably boranes, as their acceptor functionalities have undoubtedly spearheaded these developments, with remarkable results having been achieved in catalytic hydrogenation and hydrosilylation. Motivated by these developments as well as by our fundamental interest in the chemistry of heavy group 15 elements, we became fascinated by the possibility of employing antimony centers as Lewis acids within ambiphilic ligands. The chemistry of antimony-based ligands, most often encountered as trivalent stibines, has historically been considered to mirror that of their lighter phosphorus-based congeners. There is growing evidence, however, that antimony-based ligands may display unique coordination behavior and reactivity. Additionally, despite the diverse Lewis acid and redox chemistry that antimony exhibits, there have been only limited efforts to explore this chemistry within the coordination sphere of a transition metal. By incorporation of antimony into the framework of polydentate ligands in order to enforce the main group metal-transition metal interaction, the effect of redox and coordination events at the antimony center on the structure, electronics, and reactivity of the metal complex may be investigated. This Account describes our group's continuing efforts to probe the coordination behavior, reactivity, and application of ambiphilic ligands incorporating antimony centers. Structural and theoretical studies have established that both Sb(III) and Sb(V) centers in polydentate ligands may act as Z-type ligands toward late

  1. Microstructures and oxidation behavior of some Molybdenum based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Pratik Kumar [Iowa State Univ., Ames, IA (United States)

    2011-01-01

    The advent of Ni based superalloys revolutionized the high temperature alloy industry. These materials are capable of operating in extremely harsh environments, comprising of temperatures around 1050 C, under oxidative conditions. Demands for increased fuel efficiency, however, has highlighted the need for materials that can be used under oxidative conditions at temperatures in excess of 1200 C. The Ni based superalloys are restricted to lower temperatures due to the presence of a number of low melting phases that melt in the 1250 - 1450 C, resulting in softening of the alloys above 1000 C. Therefore, recent research directions have been skewed towards exploring and developing newer alloy systems. This thesis comprises a part of such an effort. Techniques for rapid thermodynamic assessments were developed and applied to two different systems - Mo-Si alloys with transition metal substitutions (and this forms the first part of the thesis) and Ni-Al alloys with added components for providing high temperature strength and ductility. A hierarchical approach towards alloy design indicated the Mo-Ni-Al system as a prospective candidate for high temperature applications. Investigations on microstructures and oxidation behavior, under both isothermal and cyclic conditions, of these alloys constitute the second part of this thesis. It was seen that refractory metal systems show a marked microstructure dependence of oxidation.

  2. A Computationally Based Approach to Homogenizing Advanced Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jablonski, P D; Cowen, C J

    2011-02-27

    We have developed a computationally based approach to optimizing the homogenization heat treatment of complex alloys. The Scheil module within the Thermo-Calc software is used to predict the as-cast segregation present within alloys, and DICTRA (Diffusion Controlled TRAnsformations) is used to model the homogenization kinetics as a function of time, temperature and microstructural scale. We will discuss this approach as it is applied to both Ni based superalloys as well as the more complex (computationally) case of alloys that solidify with more than one matrix phase as a result of segregation. Such is the case typically observed in martensitic steels. With these alloys it is doubly important to homogenize them correctly, especially at the laboratory scale, since they are austenitic at high temperature and thus constituent elements will diffuse slowly. The computationally designed heat treatment and the subsequent verification real castings are presented.

  3. Heat-treated Saccharomyces cerevisiae for antimony speciation and antimony(III) preconcentration in water samples

    International Nuclear Information System (INIS)

    An analytical method was developed for antimony speciation and antimony(III) preconcentration in water samples. The method is based on the selective retention of Sb(III) by modified Saccharomyces cerevisiae in the presence of Sb(V). Heat, caustic and solvent pretreatments of the biomass were investigated to improve the kinetics and thermodynamics of Sb(III) uptake process at room temperature. Heating for 30 min at 80 deg. C was defined as the optimal treatment. Antimony accumulation by the cells was independent of pH (5-10) and ionic strength (0.01-0.1 mol L-1). 140 mg of yeast and 2 h of contact were necessary to ensure quantitative sequestration of Sb(III) up to 750 μg L-1. In these conditions, Sb(V) was not retained. Sb(V) was quantified in sorption supernatant by inductively coupled plasma mass spectrometry (ICP-MS) or inductively coupled plasma optical emission spectrometry (ICP-OES). Sb(III) was determined after elution with 40 mmol L-1 thioglycolic acid at pH 10. A preconcentration factor close to nine was achieved for Sb(III) when 100 mL of sample was processed. After preconcentration, the detection limits for Sb(III) and Sb(V) were 2 and 5 ng L-1, respectively, using ICP-MS, 7 and 0.9 μg L-1 using ICP-OES. The proposed method was successfully applied to the determination of Sb(III) and Sb(V) in spiked river and mineral water samples. The relative standard deviations (n = 3) were in the 2-5% range at the tenth μg L-1 level and less than 10% at the lowest Sb(III) and Sb(V) tested concentration (0.1 μg L-1). Corrected recoveries were in all cases close to 100%

  4. The shape memory effect in systems Cu-based alloys

    OpenAIRE

    2013-01-01

    330a The aim of this work was to analyse the mechanisms of hindered internal passivation of silver based alloys which was obtained by the modification of basic chemical composition. A generalisation of the phenomenon, experimental verification and the estimated range of micro-element concentration is also introduced. The ability for inoculation of a particular alloy is determined by the differences between the formation energies of oxides, as well as their crystallographic similarity. Therefo...

  5. Incorporation of Refractory Metals into Niobium Base Alloys

    OpenAIRE

    Antoni-Zdziobek, A.; Driole, J.; Durand, F; Durand, Franck

    1995-01-01

    Niobium-based alloys with additions such as Al, Ti and Mo were prepared in an inductive cold crucible. A process route was established to provide homogeneous ingots. Key ideas concerning the application of inductive cold crucible to preparation of refractory alloys are brought out. A model is proposed to explain and quantify the experimental observations, which couples the diffusive and convective heat transfers and the heat of mixing involved.

  6. Stabilized nanocrystalline iron-based alloys: Guiding efforts in alloy selection

    International Nuclear Information System (INIS)

    Highlights: → A regular solution model for solute segregation is capable of estimating the effect of solutes on the stability of nanocrystalline Fe. → Stability increases for solutes having larger heats of segregation. → Zr and Ta had an effect on stabilizing the nanocrystalline microstructure of Fe, while Cr and Ni did not. - Abstract: Using a modified regular solution model for grain boundary solute segregation, the relative thermal stability of a number of Fe-based nanocrystalline binary alloys was predicted with considerable accuracy. It was found that nanocrystalline iron was strongly stabilized by zirconium, moderately stabilized by tantalum, and not significantly stabilized by nickel or chromium. These findings are fully in line with the aforementioned predictions. This success with iron based alloys highlights the utility of this practical approach to selecting stabilizing solutes for nanocrystalline alloys.

  7. Effect of Annealing on Rare Earth Based Hydrogen Storage Alloys

    Institute of Scientific and Technical Information of China (English)

    Li Jinhua

    2004-01-01

    Rare earth-based hydrogen storage alloy used as negative electrode materials for nickel-metal hydride (Ni-MH) batteries are used commercially.The effect of annealing treatment with different annealing temperature and time on the MLNi3.68 Co0.78 Mn0.35 Al0.27 and MMNi3.55 Co0.75 Mn0.40 Al0.30 alloys were investigated.The crystal microstructure,pressure-composition-isotherms (p-C-T) and electrochemical properties of alloys were examined by X-ray diffraction (XRD), automatic PCI monitoring system and electrical performance testing instruments.The optimum annealing treatment conditions of two kinds of alloys were determined.

  8. Characterization of the microstructure in Mg based alloy

    KAUST Repository

    Kutbee, Arwa T

    2013-06-01

    The cast products Mg–Sn based alloys are promising candidates for automobile industries, since they provide a cheap yet thermally stable alternative to existing alloys. One drawback of the Mg–Sn based alloys is their insufficient hardness. The hardenability can be improved by engineering the microstructure through additions of Zn to the base alloy and selective aging conditions. Therefore, detailed knowledge about the microstructural characteristics and the role of Zn to promote precipitation hardening is essential for age hardenable Mg-based alloys. In this work, microstructural investigation of the Mg–1.4Sn–1.3Zn–0.1Mn (at.%) precipitation system was performed using TEM. The chemical composition of the precipitates was analyzed using EDS. APT was employed to obtain precise chemical information on the distribution of Zn in the microstructure. It was found from microstructural studies that different precipitates with varying sizes and phases were present; lath-shaped precipitates of the Mg2Sn phase have an incoherent interface with the matrix, unlike the lath-shaped MgZn2 precipitates. Furthermore, nano-sized precipitates dispersed in the microstructure with short-lath morphology can either be enriched with Sn or Zn. On the other hand, APT analysis revealed the strong repulsion between Sn and Zn atoms in a portion of the analysis volume. However, larger reconstruction volume required to identify the role of Zn is still limited to the optimization of specimen preparation.

  9. Creep properties of Zr-based alloys with Zr-xNb-xSn-Fe-Cr-Mn alloying system

    International Nuclear Information System (INIS)

    To investigate the effect of Nb and Sn on the mechanical properties of Zr-based alloys with Zr-xNb-xSn-Fe-Cr-Mn alloying system, the Zr-based alloys were manufactured as two kinds of sheet specimens and tested for tensile properties and creep behaviors. PK2 alloy, which have more Sn content than Nb, showed higher tensile strength and creep resistance than PK1 alloy. With rising the applied stress and test temperature, PK1 and PK2 alloys increased the steady state creep rate and activation energy for the creep of the alloys. This behavior would be due to the effect of solid-solution hardening of Sn and the dislocation in worked structure. The stress exponent of the alloys also increased in response to rise the applied stress at the constant temperature. In the stress range of 50 to 180 MPa at 350 .deg. C and 400 .deg. C, the alloys showed creep deformation behavior due to diffusion and viscous dislocation glide mechanism below 4 of the stress exponent (n). Based on the higher stress exponent than 7. It is thought that the alloys were strained by dislocation climb mechanism at the applied stress over 100 MPa at 450 .deg. C

  10. Durable pd-based alloy and hydrogen generation membrane thereof

    Science.gov (United States)

    Benn, Raymond C.; Opalka, Susanne M.; Vanderspurt, Thomas Henry

    2010-02-02

    A durable Pd-based alloy is used for a H.sub.2-selective membrane in a hydrogen generator, as in the fuel processor of a fuel cell plant. The Pd-based alloy includes Cu as a binary element, and further includes "X", where "X" comprises at least one metal from group "M" that is BCC and acts to stabilize the .beta. BCC phase for stability during operating temperatures. The metal from group "M" is selected from the group consisting of Fe, Cr, Nb, Ta, V, Mo, and W, with Nb and Ta being most preferred. "X" may further comprise at least one metal from a group "N" that is non-BCC, preferably FCC, that enhances other properties of the membrane, such as ductility. The metal from group "N" is selected from the group consisting of Ag, Au, Re, Ru, Rh, Y, Ce, Ni, Ir, Pt, Co, La and In. The at. % of Pd in the binary Pd--Cu alloy ranges from about 35 at. % to about 55 at. %, and the at. % of "X" in the higher order alloy, based on said binary alloy, is in the range of about 1 at. % to about 15 at. %. The metals are selected according to a novel process.

  11. Redistribution associate impurity by annealing of rapidly solidified Al-Fe alloys studied by means of rutherford backscattering spectroscopy

    International Nuclear Information System (INIS)

    The associate antimony-impurity distribution in rapidly solidified Al-Fe alloy foils has been investigated. It was determinate by Rutherford backscattering spectroscopy technique that the antimony distribution in Al-Fe alloys is irregular. The antimony concentration at the foil surface (0.04 μm) is increased reaching 0.2 at. % by annealing at 140 0C - 500 0C temperature range

  12. Cyclic and Linear Polarization of Yttrium-Containing Iron-Based Amorphous Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Day, S D; Lian, T; Farmer, J C; Rebak, R B

    2007-08-10

    Iron-based amorphous alloys are produced by rapid solidification from the melt. These alloys may possess unique mechanical and corrosion resistant properties. The chemical composition of the alloy may influence the cooling rate that is necessary for the alloys to be completely vitreous. At the same time, the corrosion resistance of the amorphous alloys may also depend on their chemical composition. This paper examines the anodic behavior of iron-based amorphous alloys containing three different concentrations (1, 3 and 5 atomic %) of yttrium (Y) in several electrolyte solutions. Results from polarization resistance potentiodynamic polarization show that when the alloy contains 5% atomic Y, the corrosion resistance decreases.

  13. Variations of color with alloying elements in Pd-free Au-Pt-based high noble dental alloys

    International Nuclear Information System (INIS)

    The effects of alloying addition of a small amount of base metals (In, Sn, Fe, Zn) on color variations in Pd-free Au-Pt-based high noble dental alloys were investigated in terms of rectilinear and polar color coordinates. The ternary Au-Pt-X (X = In, Sn, Fe, Zn) and quaternary Au-Pt-In-Y (Y = Sn, Fe, Zn) alloys were prepared from high purity component metals. The amount of alloying base metals, X and Y, were restricted up to 2 at.%. The alloying addition of a small amount of Fe, In, Sn, to a binary Au-10 at.% Pt alloy (referred to as AP10) effectively increased chroma, C *. On the other hand, the addition of Zn to the parent alloy AP10 did not change color coordinates greatly. The increase in chroma in the present Au-Pt-based high noble alloys was attributed to the increase in the slope of spectral reflectance curve at its absorption edge near 515 nm. It was found that the addition of a small amount of Fe to the parent alloy AP10 markedly increased lightness, L *, and the addition of Sn gave a very light tint of red to the parent alloy. Although red-green chromaticity index a * contributed to chroma to some extent, contribution of yellow-blue chromaticity index b * was much greater in determining chroma in this Pd-free Au-Pt-based multi-component alloys. The present results are expected to be valuable in case color is to be taken into account in designing Pd-free Au-Pt-based high noble dental alloys

  14. 氢化物发生-原子荧光光谱法测定合金钢及合金中痕量元素铅、锡、砷、锑、铋的进展%Determination Progress of Trace Elements (Lead, Tin, Arsenic, Antimony, Bismuth)in Staliness Steel Alloys by HF-AFS

    Institute of Scientific and Technical Information of China (English)

    赵艳兵; 刘爱坤; 戴学谦; 王珺

    2011-01-01

    通过对近年来有关氢化物发生-原子荧光光谱法在复杂基体体系中痕量元素检测方面的资料总结,阐述了氢化物发生-原子荧光光谱法分析过程中的干扰类型、干扰机理及消除干扰的措施,对其在合金钢及合金中痕量元素铅、锡、砷、锑、铋测定中的应用进展作了评述,并对氢化物发生-原子荧光光谱法的发展前景提出了展望。%This paper presented a data summary of determination of trace elements in a complex matrix system by HG-AFS,covering the recent years. The interference type, interference mechanism and measures to eliminate interference of HG-AFS were also described. We reviewed the progress of the determination application of the Staliness Steel Alloys of trace elements, tin, lead, arsenic, antimony bismuth.We also discussed the HG-AFS development prospect.

  15. Cobalt-based ferromagnetic shape memory alloys

    Czech Academy of Sciences Publication Activity Database

    Kopeček, Jaromír; Jarošová, Markéta; Drahokoupil, Jan; Majtás, Dušan; Kratochvílová, Irena; Heczko, Oleg

    Beijing : Chinese Association for Crystal Growth, 2010 - (Jiang, M.; Chen, C.). GM2 ISBN N. [International Conference on Crystal Growth /16./ (ICCG-16). 08.08.2010-13. 08.2010, Beijing] R&D Projects: GA ČR(CZ) GA101/09/0702; GA ČR GAP107/10/0824 Institutional research plan: CEZ:AV0Z10100520 Keywords : shape memory alloys * crystal growth * SBSD method * metallography Subject RIV: BM - Solid Matter Physics ; Magnetism http://210.72.154.189/Prelim_Abstract_Display.php?EID=1757

  16. FIRST REPORT ON OTOTOXICITY OF MEGLUMINE ANTIMONIATE

    Directory of Open Access Journals (Sweden)

    Cláudia Maria Valete-Rosalino

    2014-09-01

    Full Text Available Introduction: Pentavalent antimonials are the first drug of choice in the treatment of tegumentary leishmaniasis. Data on ototoxicity related with such drugs is scarcely available in literature, leading us to develop a study on cochleovestibular functions. Case Report: A case of a tegumentary leishmaniasis patient, a 78-year-old man who presented a substantial increase in auditory threshold with tinnitus and severe rotatory dizziness during the treatment with meglumine antimoniate, is reported. These symptoms worsened in two weeks after treatment was interrupted. Conclusion: Dizziness and tinnitus had already been related to meglumine antimoniate. However, this is the first well documented case of cochlear-vestibular toxicity related to meglumine antimoniate.

  17. Cr{sub 2}Nb-based alloy development

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.T.; Tortorelli, P.F.; Horton, J.A.; Easton, D.S.; Heatherly, L.

    1996-06-01

    The objective of this work is to develop a new generation of structural materials based on intermetallic alloys for use at high temperatures in advanced fossil energy conversion systems. Target applications of such ultrahigh strength alloys include hot components (for example, air heat exchangers) in advanced energy conversion systems and heat engines. However, these materials may also find use as wear-resistant parts in coal handling systems (for example, nozzles), drill bits for oil/gas wells, and valve guides in diesel engines. One potential class of such alloys is that based on Cr-Cr{sub 2}Nb alloys. The intermetallic phase, Cr{sub 2}Nb, with a complex cubic structure (C-15) has been selected for initial development because of its high melting point (1770{degrees}C), relatively low material density (7.7 g/cm{sup 2}), and excellent high-temperature strength (at 1000 to 1250{degrees}C). This intermetallic phase, like many other Laves phases, has a wide range of compositional homogeneity suggesting the possibility of improving its mechanical and metallurgical properties by alloying additions.

  18. Strain heterogeneity and the production of coarse grains in mechanically alloyed iron-based PM2000 alloy

    OpenAIRE

    Capdevila, Carlos; Miller, U; Jelenak, H; Bhadeshia, H. K. D. H.

    2001-01-01

    Mechanically alloyed iron-based ODS alloys have the potential for application in heat exchangers for biomass processing, with gas operating temperatures and pressures of approximately 1100°C and 15–30 bar. The yttria dispersion in such alloys improves the high-temperature creep and stress rupture life. The elevated temperature strength is enhanced by the development of a coarse-grained microstructure during recrystallisation. Factors controlling the evolution of this desirable micros...

  19. Hot rolling of intermetallics FeAl phase based alloys

    Directory of Open Access Journals (Sweden)

    G. Niewielski

    2008-02-01

    Full Text Available Purpose: The one of major problem restricting universal employment of intermetallic phase base alloy istheir low plasticity which leads to hampering their development as construction materials. The following workconcentrates on possibilities to form through rolling process the alloys with various aluminium content.Design/methodology/approach: After casting and annealing, alloy specimens were subjected to axialsymmetriccompression at temperatures ranging from 900 to 1200°C at 10 s-1 strain rates. In order to analyse theprocesses which take place during deformation, the specimens after deformation were intensely cooled with water.Structural examination was carried out using light microscopy. The process was conducted on the K -350 quartorolling mill used for hot rolling of flat products. The process was conducted in some stages in at temperaturesranging from 1200-900°C:Findings: The research carried out enabled the understanding of the phenomena taking place during hot rolling ofthe investigated alloy. An alloy with 38%at. aluminium concentration can be plastically formed at a temperature of upto 900°C, which has been also confirmed in plastometric studies conducted in the form of hot compression tests.Research limitations/implications:Practical implications: The obtained sheets can be used as constructional elements working in complex stressfields, at a high temperature and corrosive environmentsOriginality/value: The tests have shown that it is possible to form the investigated alloys through rolling processingonly where shields are applied. Rolling of the alloys without shields led to the occurrence of a grid of cracks.

  20. Positron lifetime study in dilute electron irradiated lead based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Moya, G. [Lab. de Physique des Materiaux, 13 Marseille (France); Li, X.H. [D.R.F.M., S.P.2.M., M.P., C.E.N.G., 38 Grenoble (France); Menai, A. [Lab. de Physique des Materiaux, 13 Marseille (France); Kherraz, M. [Lab. de Physique des Materiaux, 13 Marseille (France); Amenzou, H. [Lab. de Physique des Materiaux, 13 Marseille (France); Bernardini, J. [Lab. de Metallurgie, 13 Marseille (France); Moser, P. [D.R.F.M., S.P.2.M., M.P., C.E.N.G., 38 Grenoble (France)

    1995-06-01

    The recovery of defects in two dilute solute-lead based alloys (Pb-Au, Pb-Cd) has been followed by positron lifetime measurements after a 3 MeV electron irradiation at 20 K. Two distinct isochronal annealing stages, the first centred at about 150 K and the other around 275 K, are to be observed as exactly the same in both the pure Pb and dilute alloys but the vacancy clustering over the second stage seen in lead and Pb-Au is completely suppressed in the Pb-Cd alloy. The results are discussed in terms of a high interaction between the cadmium atoms and vacancies in agreement with a probable presence of atomic excitons. (orig.)

  1. Enhanced Corrosion Resistance of Iron-Based Amorphous Alloys

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-02-18

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

  2. Positron lifetime study in dilute electron irradiated lead based alloys

    International Nuclear Information System (INIS)

    The recovery of defects in two dilute solute-lead based alloys (Pb-Au, Pb-Cd) has been followed by positron lifetime measurements after a 3 MeV electron irradiation at 20 K. Two distinct isochronal annealing stages, the first centred at about 150 K and the other around 275 K, are to be observed as exactly the same in both the pure Pb and dilute alloys but the vacancy clustering over the second stage seen in lead and Pb-Au is completely suppressed in the Pb-Cd alloy. The results are discussed in terms of a high interaction between the cadmium atoms and vacancies in agreement with a probable presence of atomic excitons. (orig.)

  3. 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.

  4. Positron lifetime study in dilute electron irradiated lead based alloys

    International Nuclear Information System (INIS)

    The recovery of defects in two dilute solute-lead based alloys (Pb-Au, Pb-Cd) has been followed by positron lifetime measurements after a 3 MeV electron irradiation at 20 K. Two distinct isochronal annealing stages, the first centered at about 150 K and the other around 275 K, are to be observed as exactly the same in both the pure Pb and dilute alloys but the vacancy clustering over the second stage seen in lead and Pb-Au is completely suppressed in the Pb-Cd alloy. The results are discussed in terms of a high interaction between the cadmium atoms and vacancies in agreement with a probable presence of atomic excitons. (authors). 3 figs., 9 refs

  5. Effect of B addition to hypereutectic Ti-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Louzguina-Luzgina, Larissa V. [Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai 980-8577 (Japan); Louzguine-Luzgin, Dmitri V. [WPI Advanced Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai 980-8577 (Japan)], E-mail: dml@imr.tohoku.ac.jp; Inoue, Akihisa [WPI Advanced Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai 980-8577 (Japan)

    2009-04-17

    The structure and mechanical properties of Ti-Fe-B and Ti-Fe-Co-B alloys produced in the shape of the arc-melted ingots of about 25 mm diameter and 10 mm height are studied. The hypereutectic alloys showed excellent compressive mechanical properties. The structures of the high-strength and ductile hypereutectic alloys studied by X-ray diffractometry and scanning electron microscopy were found to consist of the primary cubic cP2 intermetallic compound (TiFe-phase or a solid solution on its base) and a dispersed eutectic consisting of this cP2 intermetallic compound + BCC cI2 {beta}-Ti supersaturated solid solution phase. The addition of B increased mechanical strength. Si causes embrittlement owing to the formation of alternative intermetallic compounds. The structure and deformation behaviour were studied.

  6. (Vapor + Liquid) Equilibrium (VLE) for Binary Lead-Antimony System in Vacuum Distillation: New Data and Modeling Using Nonrandom Two-Liquid (NRTL) Model

    Science.gov (United States)

    Xu, Junjie; Kong, Lingxin; Xu, Baoqiang; Yang, Bin; You, Yanjun; Xu, Shuai; Zhou, Yuezhen; Li, Yifu; Liu, Dachun

    2016-09-01

    In this work, new experimental vapor-liquid equilibrium (VLE) data of lead-antimony alloy (Pb-Sb alloy) in vacuum distillation are reported. The activity coefficients of components of Pb-Sb alloy were calculated by using the NRTL model. The calculated average relative deviations were ±0.1425 and ±0.2433 pct, and the average standard deviations were ±0.0009 and ±0.0007, respectively, for Pb and Sb. The VLE phase diagrams, such as the temperature composition ( T- x) and pressure composition ( P-x) diagrams of Pb-Sb alloy in vacuum distillation were predicted based on the NRTL model and VLE theory. The predicted results are consistent with the new experimental data indicating that VLE phase diagrams obtained by this method are reliable. The VLE phase diagrams of alloys will provide an effective and intuitive way for the technical design and realization of recycling and separation processes. The VLE data may be used in separation processes design, and the thermodynamic properties as the key parameters in specific applications.

  7. Structure and magnetic properties of Fe-based amorphous alloys

    Directory of Open Access Journals (Sweden)

    K. Błoch

    2013-12-01

    Full Text Available Purpose: This paper presents studies relating to the structure, magnetic properties and thermal stability of the following bulk amorphous alloys: Fe61Co10Ti3-xY6+xB20 (where x = 0 or 1 Design/methodology/approach: The investigated samples were prepared in the form of rods by using the suction-casting method. The material structures were investigated using X-ray diffractometry and Mössbauer spectroscopy. The thermal stability was determined on the basis of Differential Scanning Calorimetry (DSC plots The magnetic properties were studied using a completely automated set up for measuring susceptibility and its disaccommodation. Findings: It was found that both alloys were amorphous in the as-cast state. The DSC curve obtained for Fe61Co10Ti2Y7B20 alloy exhibited one exothermic peak, while for the Fe61Co10Ti3Y6B20 sample, two peaks were distinguishable, corresponding to the crystallization of the sample. The bifurcation of the maximum on the DSC curve for the Fe61Co10Ti3Y6B20 sample may also testify to the presence of the primary crystallizing phase (FeCo23B6 [1,2]. Data obtained from the analysis of the magnetic susceptibility disaccommodation curves clearly show that in the Fe61Co10Ti3Y6B20 alloy there is less free volumes than in the second of the investigated alloys, this results in a lesser range of relaxation time. Moreover, Fe61Co10Ti3Y6B20 alloy exhibits the better time and thermal stability of magnetic properties In both of the studied alloys, at low frequencies, the total losses were comparable with those observed in classical silicon-iron alloys. Practical implications: A Ferrometer was used for the determination of core losses. Originality/value: The paper presents some researches of the Fe-based bulk amorphous alloys obtained by the suction-casting method.

  8. Purely inorganic coatings based on nanoparticles for magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Feil, Florian [DECHEMA e.V., Karl-Winnacker-Institut, Frankfurt am Main (Germany)], E-mail: feil@dechema.de; Fuerbeth, Wolfram; Schuetze, Michael [DECHEMA e.V., Karl-Winnacker-Institut, Frankfurt am Main (Germany)

    2009-03-30

    The chemical nanotechnology is offering a chance to apply stable inorganic coatings onto magnesium alloys. The cast alloy AZ91 as well as the wrought alloy AZ31 could be dip-coated with aqueous dispersions based on commercially available silica particles and various additives. The high surface activity of the nanoparticles and appropriate additives, e.g. boron, aluminium or alkali salts, help to densify these coatings under moderate conditions even suitable for those thermally precarious magnesium alloys. Another coating technique is based on the electrophoretic deposition of nanoparticles already containing all sintering aids. These particles could be synthesised by a base-catalysed sol-gel process. Polydiethoxysiloxane can act as an adhesion promoter for these coatings. Additionally concentration gradients of different oxides within these particles can adjust the coating properties, too. Usually single coatings are very thin (200-500 nm). However, multiple coating applications as well as a process involving special particle mixtures lead to coatings with a thickness of up to several micrometers. Even after thermal treatment at 200 or 400 deg. C these coatings stay crack-free. The composition and texture of these coatings were studied using IR, atomic force microscopy (AFM), scanning electron microscopy (SEM) and other techniques. Electrochemical impedance measurements show an improvement of the corrosion performance by these coatings. The coating resistance is improving with the coating thickness.

  9. DNA cleavage, antimicrobial studies and a DFT-based QSAR study of new antimony(III) complexes as glutathione reductase inhibitor.

    Science.gov (United States)

    Tunç, Turgay; Koç, Yasemin; Açık, Leyla; Karacan, Mehmet Sayım; Karacan, Nurcan

    2015-02-01

    New antimony(III) complexes, [Sb(2-aminopyridine)2Cl3] (1a), [Sb(2-aminopyridine)2Br3] (1b), [Sb(5-methyl-2-aminopyridine)2Cl3] (2a), [Sb(5-methyl-2-aminopyridine)2Br3] (2b), [Sb(2-aminopyrimidine)2Cl3] (3a), [Sb(2-aminopyrimidine)2Br3] (3b), [Sb(4,6-dimethoxy-2-aminopyrimidine)2Cl3] (4a), [Sb(4,6-dimethoxy-2-aminopyrimidine)2Br3] (4b), [Sb(2-amino-1,3,5-triazine)2Cl3] (5a), [Sb(2-amino-1,3,5-triazine)2Br3] (5b), [Sb(2-guanidinobenzimidazole) Cl3] (6a), [Sb(2-guanidinobenzimidazole)Br3] (6b) [Sb(2- benzyl-2-thiopseudeourea)2Cl3] (7a) and [Sb(2- benzyl-2-thiopseudeourea)2Br3] (7b) were synthesized. Their structures were characterized by elemental analysis, molecular conductivity, FT-IR, (1)H NMR, LC-MS techniques. Glutathione reductase inhibitor activity, antimicrobial activity and DNA cleavage studies of the complexes were determined. The geometrical structures of the complexes were optimized by DFT/B3LYP method with LANL2DZ as basis set. Calculation results indicated that the equilibrium geometries of all complexes have square pyramidal shape. About 350 molecular descriptors (constitutional, topological, geometrical, electrostatic and quantum chemical parameters) of the complexes were calculated by DFT/B3LYP/LANL2DZ method with CODESSA software. Calculated molecular parameters were correlated to glutathione reductase inhibitory activity values (pIC50) of all complexes by Best Multi-Linear Regression (BMLR) method. Obtained two-parameter QSAR equation shows that increase in "maximum partial charge for a H atom" and decrease in HOMO-LUMO gap would be favorable for the glutathione reductase inhibitory activity. PMID:25459701

  10. Admittance Loci Based Design of a Plasmonic Structure Using Ag-Au Bimetallic Alloy Film

    OpenAIRE

    Kaushik Brahmachari; Mina Ray

    2013-01-01

    A theoretical study based on the use of admittance loci method in the design of surface plasmon resonance (SPR) based structure using Ag-Au bimetallic alloy film of different alloy fractions and nanoparticle sizes has been reported along with some interesting performance related simulated results at 633 nm wavelength. The sensitivity and other performance parameter issues of the structure based on the choice of correct alloy fraction and nanoparticle size of Ag-Au bimetallic alloy film have a...

  11. Melt Protection of Mg-Al Based Alloys

    Directory of Open Access Journals (Sweden)

    María J. Balart

    2016-05-01

    Full Text Available This paper reports the current status of Mg melt protection in view to identify near-future challenges, but also opportunities, for Mg melt protection of Mg-Al based alloys. The goal is to design and manufacture sustainable Mg alloys for resource efficiency, recycling and minimising waste. Among alternative cover gas technologies for Mg melt protection other than SF6: commercially available technologies containing―HFC-134a, fluorinated ketone and dilute SO2―and developed technologies containing solid CO2, BF3 and SO2F2, can potentially produce toxic and/or corrosive by-products. On the other hand, additions of alkaline earth metal oxides to Mg and its alloys have developed a strong comparative advantage in the field of Mg melt protection. The near-future challenges and opportunities for Mg-Al based alloys include optimising and using CO2 gas as feedstock for both melt protection and grain refinement and TiO2 additions for melt protection.

  12. Results from investigations with an instrumented impact machine on a molybdenum base alloy, nickel base alloys, and Incoloy 800

    International Nuclear Information System (INIS)

    Experiments were performed on the molybdenum base alloy TZM, the nickel base alloys Nimocast 713 LC, Inconel 625, Nimonic 86, Hastelloy S, and the iron base alloy Incoloy 800 with an instrumented impact machine. The results are discussed in terms of absorbed impact energies and dynamic fracture toughness. In all cases the agreement between the energy determined by the dial reading and the energy determined by the integration of the load vs. load point displacement diagram was excellent. A procedure for the determination of the dynamic fracture toughness for load vs. load point displacement diagrams exhibiting high oscillations using an averaged curve is proposed. Using this procedure a pronounced influence of the experiments with tup and chisel (5.0 m/s and 0.1 m/s respectively) on the dynamic fracture toughness is not detectable. Using half the drop height, i.e. halving the total energy, lowers the dynamic fracture toughness values for these types of alloys. Low absorbed impact energies are often combined with high fracture toughness values. In these cases there is no or only a small reserve in deformation and/or stable crack growth. (Auth.)

  13. Antimony bioavailability in mine soils

    International Nuclear Information System (INIS)

    Antimony has low bioavailability in mining and smelting contaminated soils and bacterial biosensors are not suitable for its detection. - Five British former mining and smelting sites were investigated and found to have levels of total Sb of up to 700 mg kg-1, indicating high levels of contamination which could be potentially harmful. However, this level of Sb was found to be biologically unavailable over a wide range of pH values, indicating that Sb is relatively unreactive and immobile in the surface layers of the soil, remaining where it is deposited rather than leaching into lower horizons and contaminating ground water. Sb, sparingly soluble in water, was unavailable to the bacterial biosensors tested. The bioluminescence responses were correlated to levels of co-contaminants such as arsenic and copper, rather than to Sb concentrations. This suggests that soil contamination by Sb due to mining and smelting operations is not a severe risk to the environment or human health provided that it is present as immobile species and contaminated sites are not used for purposes which increase the threat of exposure to identified receptors. Co-contaminants such as arsenic and copper are more bioavailable and may therefore be seen as a more significant risk

  14. Selective liquid-liquid extraction of antimony(III from hydrochloric acid media by N-n-octylaniline in xylene

    Directory of Open Access Journals (Sweden)

    M. A. ANUSE

    2004-04-01

    Full Text Available N-n-Octylaniline in xylene was used for the extraction separation of antimony(III from hydrochloric acid media. Antimony(III was extracted quantitatively with 10 mL 4 % N-n-octylaniline in xylene. It was stripped from the organic phase with 0.5 M ammonia and estimated photometrically by the iodide method. The effect of metal ion, acid, reagent concentration and various foreign ions was investigated. The method affords binary and ternary separation of antimony(III from tellurium(IV, selenium(IV, lead(II, bismuth(III, tin(IV, germanium(IV, copper(II, gold(III, iron(III and zinc(II. The method is applicable for the analysis of synthetic mixtures, alloys and semiconductor thin films. It is fast, accurate and precise.

  15. Perspectives of antimony compounds in oncology

    Institute of Scientific and Technical Information of China (English)

    Pankaj SHARMA; Diego PEREZ; Armando CABRERA; Nee ROSAS; Jose Luis ARIAS

    2008-01-01

    Antimony, a natural element that has been used as a drug for over more than 100 years, has remarkable therapeutic efficacy in patients with acute promyelocytic leukemia. This review focuses on recent advances in developing antimony anti- cancer agents with an emphasis on antimony coordination complexes, Sb (Ⅲ) and Sb (V). These complexes, which include many organometallic complexes, may provide a broader spectrum of antitumoral activity. They were compared with classical platinum anticancer drugs. The review covers the literature data pub- lished up to 2007. A number of antimonials with different antitumoral activities are known and have diverse applications, even though little research has been done on their possibilities. It might be feasible to develop more specific and effective inhibitors for phosphatase-targeted, anticancer therapeutics through the screen- ing of sodium stibogluconate (SSG) and potassium antimonyltartrate-related compounds, which are comprised of antimony conjugated to different organic moieties. For example, SSG appears to be a better inhibitor than suramin which is a compound known for its antineoplastic activity against several types of cancers.

  16. Investigation of the Precipitation Behavior in Aluminum Based Alloys

    KAUST Repository

    Khushaim, Muna S.

    2015-11-30

    The transportation industries are constantly striving to achieve minimum weight to cut fuel consumption and improve overall performance. Different innovative design strategies have been placed and directed toward weight saving combined with good mechanical behavior. Among different materials, aluminum-based alloys play a key role in modern engineering and are widely used in construction components because of their light weight and superior mechanical properties. Introduction of different nano-structure features can improve the service and the physical properties of such alloys. For intelligent microstructure design in the complex Al-based alloy, it is important to gain a deep physical understanding of the correlation between the microstructure and macroscopic properties, and thus atom probe tomography with its exceptional capabilities of spatially resolution and quantitative chemical analyses is presented as a sophisticated analytical tool to elucidate the underlying process of precipitation phenomena in aluminum alloys. A complete study examining the influence of common industrial heat treatment on the precipitation kinetics and phase transformations of complex aluminum alloy is performed. The qualitative evaluation results of the precipitation kinetics and phase transformation as functions of the heat treatment conditions are translated to engineer a complex aluminum alloy. The study demonstrates the ability to construct a robust microstructure with an excellent hardness behavior by applying a low-energy-consumption, cost-effective method. The proposed strategy to engineer complex aluminum alloys is based on both mechanical strategy and intelligent microstructural design. An intelligent microstructural design requires an investigation of the different strengthen phases, such as T1 (Al2CuLi), θ′(Al2Cu), β′(Al3Zr) and δ′(Al3Li). Therefore, the early stage of phase decomposition is examined in different binary Al-Li and Al-Cu alloys together with different

  17. CuZn Alloy- Based Electrocatalyst for CO2 Reduction

    KAUST Repository

    Alazmi, Amira

    2014-06-01

    ABSTRACT CuZn Alloy- Based Electrocatalyst for CO2 Reduction Amira Alazmi Carbon dioxide (CO2) is one of the major greenhouse gases and its emission is a significant threat to global economy and sustainability. Efficient CO2 conversion leads to utilization of CO2 as a carbon feedstock, but activating the most stable carbon-based molecule, CO2, is a challenging task. Electrochemical conversion of CO2 is considered to be the beneficial approach to generate carbon-containing fuels directly from CO2, especially when the electronic energy is derived from renewable energies, such as solar, wind, geo-thermal and tidal. To achieve this goal, the development of an efficient electrocatalyst for CO2 reduction is essential. In this thesis, studies on CuZn alloys with heat treatments at different temperatures have been evaluated as electrocatalysts for CO2 reduction. It was found that the catalytic activity of these electrodes was strongly dependent on the thermal oxidation temperature before their use for electrochemical measurements. The polycrystalline CuZn electrode without thermal treatment shows the Faradaic efficiency for CO formation of only 30% at applied potential ~−1.0 V vs. RHE with current density of ~−2.55 mA cm−2. In contrast, the reduction of oxide-based CuZn alloy electrode exhibits 65% Faradaic efficiency for CO at lower applied potential about −1.0 V vs. RHE with current density of −2.55 mA cm−2. Furthermore, stable activity was achieved over several hours of the reduction reaction at the modified electrodes. Based on electrokinetic studies, this improvement could be attributed to further stabilization of the CO2•− on the oxide-based Cu-Zn alloy surface.

  18. Preparation of nanosized antimony by mechanochemical reduction of antimony sulphide Sb2S3

    International Nuclear Information System (INIS)

    The preparation of nanosized antimony (grain size 19 nm) by high-energy milling of antimony sulphide Sb2S3 with elemental Fe as reducing element is reported. The mechanochemical reduction was performed in a planetary ball mill for 10-180 min. The process is rather straightforward with elemental antimony and iron sulphide (pyrrhotite-4H) being the only solid-state products. The process kinetics as described by X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) magnetometry shows that most of the reduction is complete after 60 min of milling

  19. Effect of Impurities and Cerium on Stress Concentration Sensitivity of Al-Li Based Alloys

    Institute of Scientific and Technical Information of China (English)

    孟亮; 田丽

    2002-01-01

    A notch sensitivity factor was derived in order to evaluate the stress concentration sensitivity of Al-Li based alloys. The factor values for the Al-Li alloy sheets containing various contents of impurities and cerium addition were evaluated by determining the mechanical properties. It is found that the impurities Fe, Si, Na and K significantly enhance the stress concentration sensitivity of the alloys 2090 and 8090, whereas cerium addition reduces the stress concentration sensitivity to a certain degree for the high strength alloys. However, an excess amount of cerium addition in the high ductility alloy 1420 can significantly increase the stress concentration sensitivity. As compared with conventional aluminum alloys, the Al-Li based alloys generally show high stress concentration sensitivity. Therefore, a special attention must be paid to this problem in the practical application of Al-Li based alloys.

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

    International Nuclear Information System (INIS)

    Spangles produced by batch hot-dip galvanizing process have a rougher surface and a greater surface segregation of alloying element compared with those in continuous hot-dip galvanizing line (CGL), owing to the cooling rate of the former is much smaller than that of the later. Therefore, typical spangles on a batch hot-dipped Zn-0.05Al-0.2Sb alloy coating were investigated. The chemical, morphological characterization and identification of the phases on the spangles were examined by scanning electron microscopy (SEM), backscattered electron imaging (BSE), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS) and X-ray diffraction analysis (XRD). The results showed that the coating surface usually exhibited three kinds of spangles: shiny, feathery and dull spangle, of which extensively antimony surface segregation was detected. The nature of precipitate on the coating surface was identified as β-Sb3Zn4, The precipitated β-Sb3Zn4 particles distributed randomly on the shiny spangle surface, both β-Sb3Zn4 particles and dentritic segregation of antimony dispersed in the dendritic secondary arm spacings of the feathery spangle and on the whole dull spangle surface. The dentritic segregation of antimony and precipitation of Sb3Zn4 compound are discussed by a proposed model.

  1. Smart materials based on shape memory alloys: examples from Europe

    International Nuclear Information System (INIS)

    Shape memory alloys (SMAs) have become increasingly attractive as embedded actuators in polymers yielding adaptive composite structures. In particular, SMA-elements have been used to actively or passively control shape, elastic modules, internal stress level and damping capacity of such smart composites. In the passive approach, copper-base SMA-plates can be used as temperature-sensitive damping elements, an interesting solution to improve the vibrational behaviour of alpine skis for example. Active materials are obtained by the integration of pre-strained Ni-Ti-base thin wires in polymer matrix composites enabling control of the vibrational behaviour through the recovery-stress tuning technique. In this paper, some results of national research programmes in Belgium and Switzerland, mainly concerning the damping capacity, are shown and a new European project entitled ''adaptive composites with embedded shape memory alloy wires'' is presented in which partners from Belgium, Germany, Greece, Great Britain and Switzerland are collaborating. (orig.)

  2. Cr{sub 2}Nb-based alloy development

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.T.; Tortorelli, P.F.; Horton, J.A. [Oak Ridge National Lab., TN (United States)] [and others

    1995-06-01

    The objective of this task is to develop a new generation of structural materials based on intermetallic alloys for use as critical hot components in advanced fossil energy conversion systems. The intermetallic phase, Cr{sub 2}Nb, with a complex cubic structure (C-15) has been selected for this development because of its high melting point (1770{degrees}C), relatively low material density (7.7 g/cm{sup 2}), excellent high-temperature strength (at 1000 to 1250{degrees}C), and potential resistance to oxidation and corrosion. This intermetallic phase, like many other Laves phases, has a wide range of compositional homogeneity suggesting the possibility of improving its mechanical and metallurgical properties by alloying additions. The major engineering concern with Cr{sub 2}Nb and other A{sub 2}B Laves phases is their poor fracture toughness and fracture resistance at ambient temperatures. The single-phase Cr{sub 2}Nb is very hard ({approximately}800 DPH) and brittle at room temperature. Because of this brittleness, the development effort has concentrated on two-phase structures containing the hard intermetallic phase Cr{sub 2}Nb and the softer Cr-rich solid solution phase. Potential applications of Cr-Cr{sub 2}Nb alloys include hot components (for example, air heat exchangers and turbine blades) in advanced energy conversion systems and heat engines, wear-resistant parts in coal handling systems (e.g., nozzles), drill bits for oil/gas wells, and valve guides in diesel engines. Current studies are focuses on enhancement of fracture resistance in tension at ambient temperatures and oxidation resistance above 1000{degrees}C. This report summarizes recent progress on controlling microstructure and improving the mechanical and metallurgical properties and the high-temperature corrosion behavior of Cr-Cr{sub 2}Nb alloys through alloying conditions, material processing, and heat treatment.

  3. Toughness enhancement in TiAlN-based quarternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sangiovanni, D.G., E-mail: davsan@ifm.liu.se; Chirita, V., E-mail: vio@ifm.liu.se; Hultman, L., E-mail: larhu@ifm.liu.se

    2012-03-30

    Improved toughness in hard and superhard thin films is a primary requirement for present day ceramic hard coatings, known to be prone to brittle failure during in-use conditions. We use density functional theory calculations to investigate a number of (TiAl){sub 1-x}M{sub x}N thin films in the B1 structure, with 0.06 {<=} x {<=} 0.75, obtained by alloying TiAlN with M = V, Nb, Ta, Mo and W. Results show significant ductility enhancements, hence increased toughness, in these compounds. Importantly, these thin films are also predicted to be superhard, with similar or increased hardness values, compared to Ti{sub 0.5}Al{sub 0.5} N. For (TiAl){sub 1-x}W{sub x}N the results are experimentally confirmed. The ductility increase originates in the enhanced occupancy of d-t{sub 2g} metallic states, induced by the valence electrons of substitutional elements (V, Nb, Ta, Mo, W). This effect is more pronounced with increasing valence electron concentration, and, upon shearing, leads to the formation of a layered electronic structure in the compound material, consisting of alternating layers of high and low charge density in the metallic sublattice, which in turn, allows a selective response to normal and shear stresses. - Highlights: Black-Right-Pointing-Pointer DFT calculated mechanical properties of TiAlN-based quarternary alloys. Black-Right-Pointing-Pointer (TiAl){sub 1-x}M{sub x}N alloys with M = V, Nb, Ta, Mo and W for 0.06 {<=} x {<=} 0.75. Black-Right-Pointing-Pointer Ductility enhancement induced by increased valence electron concentration (VEC). Black-Right-Pointing-Pointer Alloys predicted to be superhard, with higher hardness than TiAlN. Black-Right-Pointing-Pointer The hardness/ductility combination implies enhanced toughness in all alloys.

  4. Toughness enhancement in TiAlN-based quarternary alloys

    International Nuclear Information System (INIS)

    Improved toughness in hard and superhard thin films is a primary requirement for present day ceramic hard coatings, known to be prone to brittle failure during in-use conditions. We use density functional theory calculations to investigate a number of (TiAl)1−xMxN thin films in the B1 structure, with 0.06 ≤ x ≤ 0.75, obtained by alloying TiAlN with M = V, Nb, Ta, Mo and W. Results show significant ductility enhancements, hence increased toughness, in these compounds. Importantly, these thin films are also predicted to be superhard, with similar or increased hardness values, compared to Ti0.5Al0.5 N. For (TiAl)1−xWxN the results are experimentally confirmed. The ductility increase originates in the enhanced occupancy of d-t2g metallic states, induced by the valence electrons of substitutional elements (V, Nb, Ta, Mo, W). This effect is more pronounced with increasing valence electron concentration, and, upon shearing, leads to the formation of a layered electronic structure in the compound material, consisting of alternating layers of high and low charge density in the metallic sublattice, which in turn, allows a selective response to normal and shear stresses. - Highlights: ► DFT calculated mechanical properties of TiAlN-based quarternary alloys. ► (TiAl)1−xMxN alloys with M = V, Nb, Ta, Mo and W for 0.06 ≤ x ≤ 0.75. ► Ductility enhancement induced by increased valence electron concentration (VEC). ► Alloys predicted to be superhard, with higher hardness than TiAlN. ► The hardness/ductility combination implies enhanced toughness in all alloys.

  5. Self healing of damage in Fe-based alloys

    OpenAIRE

    Zhang, S.

    2015-01-01

    Steel components can exhibit premature and low-ductility creep fracture, when exposed to high temperatures for long times. The failure arises from the formation, growth and coalescence of ultra-fine cracks and cavities. Self healing of damage is a promising new approach to enhance the lifetime of the steel components, in particular for applications at high temperatures. This thesis aims to realize the self-healing of damage in Fe-based alloys and unravel the mechanism responsible for efficien...

  6. Combined thermodynamic study of nickel-base alloys. Progress report

    International Nuclear Information System (INIS)

    Achievements during this period are the following: (1) initiation of a high-temperature study of the Ni-Ta system using the galvanic cell technique, (2) emf study of high-temperature thermodynamics in the Ni-Mo system, (3) measured heat capacity data on ordered and disordered Ni4Mo, (4) heat capacities of Ni and disordered Ni3Fe, and (5) computer correlation of thermodynamic and phase diagram data in binary Ni-base alloys

  7. High Temperature Internal Oxidation Behavior of Iron Based Alloys

    International Nuclear Information System (INIS)

    A study of growth kinetics and microstructure of internal oxides in the iron-base alloys was carried out by an optical microscope and a scanning electron microscope, so that the growth mechanisms of the oxide precipitates in the internal oxidation zone could be understood in detail. Iron-based alloys, Fe-1%Al, Fe-1%Al-1%Hf, Fe-1%Cr, Fe-1%Cr-1%Hf and Fe-2%Hf, were oxidized in a sealed quartz tube containing Fe/FeO powder mixtures which maintained the oxygen partial pressure at the FeO decomposition pressure at 800 .deg. C for the various time periods to 121 hours. Results show that the growth rate of the oxide precipitates in the internal oxidation zone is controlled by the diffusion of oxygen. The variation of the solute element and the addition of Hf in the iron-base alloys led to a change in the depth of internal oxidation zone and in the oxide morphology. The internal precipitate adopted the form of continuous needles or feathers for the Fe-Al system, whereas that in the Fe-Cr and Fe-2%Hf systems adapted the form of discontinuous crystallites, that is, spheres or polyhedral crystallites. The mechanism of this morphological evolution was explained in detail

  8. Tribological properties of laser cladding TiB2 particles reinforced Ni-base alloy composite coatings on aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Long He; Ye-Fa Tan; Xiao-Long Wang; Qi-Feng Jing; Xiang Hong

    2015-01-01

    To improve the wear resistance of aluminum alloy frictional parts,TiB2 particles reinforced Ni-base alloy composite coatings were prepared on aluminum alloy 7005 by laser cladding.The microstructure and tribological properties of the composite coatings were investigated.The results show that the composite coating contains the phases of NiAl,Ni3Al,Al3Ni2,TiB2,TiB,TiC,CrB,and Cr23C6.Its microhardness is HV0.5 855.8,which is 15.4 % higher than that of the Ni-base alloy coating and is 6.7 times as high as that of the aluminum alloy.The friction coefficients of the composite coatings are reduced by 6.8 %-21.6 % and 13.2 %-32.4 % compared with those of the Ni-base alloy coatings and the aluminum alloys,while the wear losses are 27.4 %-43.2 % less than those of the Ni-base alloy coatings and are only 16.5 %-32.7 % of those of the aluminum alloys at different loads.At the light loads ranging from 3 to 6 N,the calculated maximum contact stress is smaller than the elastic limit contact stress.The wear mechanism of the composite coatings is micro-cutting wear,but changes into multi-plastic deformation wear at 9 N due to the higher calculated maximum contact stress than the elastic limit contact stress.As the loads increase to 12 N,the calculated flash temperature rises to 332.1 ℃.The composite coating experiences multi-plastic deformation wear,micro-brittle fracture wear,and oxidative wear.

  9. Preparation and research on poisoning resistant Zr-Co based hydrogen storage alloys

    Institute of Scientific and Technical Information of China (English)

    LI Hualing; WANG Shumao; JIANG Lijun; ZHANG Lidong; LIU Xiaopeng; LI Zhinian

    2008-01-01

    At present,all hydrogen storage alloys are poisoned by hydrogen mixed with CO,CO2,etc,which decreases the hydrogen storage property sharply.Zr-Co based hydrogen storage alloys with good poisoning resistance were prepared by alloying,fluorinating,and electroless plating.The experiment results show that the poisoning resistance of the Zr-Co based alloy was improved remarkably after the treatments.The poisoning resistance mechanism of the Zr-Co based hydrogen storage alloys was analyzed.

  10. The Membrane Electrowinning Separation of Antimony from a Stibnite Concentrate

    Science.gov (United States)

    Yang, Jian-Guang; Yang, Sheng-Hai; Tang, Chao-Bo

    2010-06-01

    The main purpose of this study was to characterize and to extract antimony from a stibnite concentrate through electrowinning. This article reports an account of a study conducted on the optimization of the process parameters for antimony pentachloride circular leaching, purification, and electrowinning of antimony from antimony trichloride solution. The effect of electrowinning parameters, such as antimony and sodium chloride concentration in the catholyte, temperature, current density, polar distance, etc., on the voltage requirement and the current efficiency (CE) of antimony electrodeposition was explored. A maximum CE of more than 97 pct was attained with a catholyte composition of 70-g/L antimony, 25-g/L NaCl, 4.5-mol/L hydrogen ion concentration, with an anolyte composition of 40-g/L antimony trichloride at a temperature of 328 K (55 °C), a 4-cm polar distance, and a cathode current density of 200 A/m2. Under the optimized conditions, the CE was more than 97 pct, and a 99.98 pct antimony plate was obtained on the cathode. The chemical content analysis of the resulting anolyte was indicated to be 97 pct antimony pentachloride and 3 pct antimony trichloride, which could be recycled to leaching tank as the leaching agent.

  11. Synthesis and application of antimony pent(isooctyl thioglycollate)

    Institute of Scientific and Technical Information of China (English)

    LIU You-nian; LI Hong-bing; SHU Wan-gen; CHEN Qi-yuan

    2005-01-01

    A new type of thermal stabilizer, antimony pent(isooctyl thioglycollate)(Sb(SCH2COOC8H17)5), was synthesized by using antimony trioxide, isooctanol and thioglycolic acid in 2 steps. Firstly, antimony trioxide was oxidized into colloidal antimony peroxide. Then antimony peroxide and isooctyl thioglycollate reacted stoichiometrically for 2 h with the yield of 87%. This compound was used as thermal stabilizer for polyvinyl chloride(PVC). The results show that the thermal stability time is 52 min at 200 ℃ by heat-ageing oven test when adding 2.5% thermal stabilizer to PVC resin. Compared with antimony tris(isooctyl thiolycollate), the initial thermal stability of antimony pent(isooctyl thioglycollate) is better than that of antimony tris(isooctyl thioglycollate), while the long-term thermal stability time is shorter than that of antimony tris(isooctyl thioglycollate). Meanwhile, the synergism of antimony pent(isooctyl thioglycollate) with calcium stearate was studied, indicating that when the mass ratio of antimony pent(isooctyl thioglycollate) to calcium stearate is 2:1, the thermal stability time of PVC is 58 min.

  12. Geothermal and fluid flowing simulation of ore-forming antimony deposits in Xikuangshan

    Institute of Scientific and Technical Information of China (English)

    YANG Ruiyan; MA Dongsheng; BAO Zhengyu; PAN Jiayong; CAO Shuanglin; XIA Fei

    2006-01-01

    The Xikuangshan Antimony Deposit located in the Mid-Hunan Basin, China, is the largest antimony deposit in the world. Based on the hydrogeological and geochemical data collected from four sections, Xikuangshan-Dajienao (AO), Xikuangshan-Dashengshan (BO), Xikuangshan-Longshan (CO) and Dafengshan (DO) in the Basin, an advanced metallogenic model related to deep-cyclic meteoric water of Xikuangshan Antimony Deposit is put forward in this paper using a model of heat-gravity-driving fluid flow transportation. The simulation results show that the ore-forming fluid of the deposit mainly comes from the Dashengshan and Longshan areas where BO and CO sections are located if the overall basin keeps a constant atmospheric precipitation and infiltration rate during mineralization, and that the average transportation speed of the ore-forming fluids is about 0.2-0.4 m/a.

  13. Microbial antimony biogeochemistry: Enzymes, regulation, and related metabolic pathways

    Science.gov (United States)

    Li, Jingxin; Qian Wang; Oremland, Ronald S.; Kulp, Thomas R.; Rensing, Christopher; Wang, Gejiao

    2016-01-01

    Antimony (Sb) is a toxic metalloid that occurs widely at trace concentrations in soil, aquatic systems, and the atmosphere. Nowadays, with the development of its new industrial applications and the corresponding expansion of antimony mining activities, the phenomenon of antimony pollution has become an increasingly serious concern. In recent years, research interest in Sb has been growing and reflects a fundamental scientific concern regarding Sb in the environment. In this review, we summarize the recent research on bacterial antimony transformations, especially those regarding antimony uptake, efflux, antimonite oxidation, and antimonate reduction. We conclude that our current understanding of antimony biochemistry and biogeochemistry is roughly equivalent to where that of arsenic was some 20 years ago. This portends the possibility of future discoveries with regard to the ability of microorganisms to conserve energy for their growth from antimony redox reactions and the isolation of new species of “antimonotrophs.”

  14. Corrosion of iron-base alloys by lithium

    International Nuclear Information System (INIS)

    A review of corrosion mechanisms operating in lithium-iron-base alloy systems is presented along with data obtained with thermal-convection loops of niobium-stabilized 2 1/4 percent Cr-1 percent Mo steel and types 304L and 321 stainless steels. A corrosion rate of 2.3 μm/year (0.09 mil/year) was obtained on the 2 1/4 percent Cr-1 percent Mo steel at 6000C. Considerably more mass transport of alloying constituents and a maximum corrosion rate of about 14 μm/year (0.55 mil/year) was obtained with the austenitic stainless steels. Results of metallography, x-ray fluorescence analysis, scanning electron microscopy, and weight-change data are presented and discussed

  15. Electrostatically defined silicon quantum dots with counted antimony donor implants

    Energy Technology Data Exchange (ETDEWEB)

    Singh, M., E-mail: msingh@sandia.gov; Luhman, D. R.; Lilly, M. P. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87175 (United States); Pacheco, J. L.; Perry, D.; Garratt, E.; Ten Eyck, G.; Bishop, N. C.; Wendt, J. R.; Manginell, R. P.; Dominguez, J.; Pluym, T.; Bielejec, E.; Carroll, M. S. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

    2016-02-08

    Deterministic control over the location and number of donors is crucial to donor spin quantum bits (qubits) in semiconductor based quantum computing. In this work, a focused ion beam is used to implant antimony donors in 100 nm × 150 nm windows straddling quantum dots. Ion detectors are integrated next to the quantum dots to sense the implants. The numbers of donors implanted can be counted to a precision of a single ion. In low-temperature transport measurements, regular Coulomb blockade is observed from the quantum dots. Charge offsets indicative of donor ionization are also observed in devices with counted donor implants.

  16. Electrostatically defined silicon quantum dots with counted antimony donor implants

    International Nuclear Information System (INIS)

    Deterministic control over the location and number of donors is crucial to donor spin quantum bits (qubits) in semiconductor based quantum computing. In this work, a focused ion beam is used to implant antimony donors in 100 nm × 150 nm windows straddling quantum dots. Ion detectors are integrated next to the quantum dots to sense the implants. The numbers of donors implanted can be counted to a precision of a single ion. In low-temperature transport measurements, regular Coulomb blockade is observed from the quantum dots. Charge offsets indicative of donor ionization are also observed in devices with counted donor implants

  17. Co-doping with antimony to control phosphorous diffusion in germanium

    KAUST Repository

    Tahini, H. A.

    2013-02-15

    In germanium, phosphorous and antimony diffuse quickly and as such their transport must be controlled in order to design efficient n-typed doped regions. Here, density functional theory based calculations are used to predict the influence of double donor co-doping on the migration activation energies of vacancy-mediated diffusion processes. The migration energy barriers for phosphorous and antimony were found to be increased significantly when larger clusters involving two donor atoms and a vacancy were formed. These clusters are energetically stable and can lead to the formation of even larger clusters involving a number of donor atoms around a vacancy, thereby affecting the properties of devices.

  18. Testing of antimony selective media for treatment of liquid radwaste

    International Nuclear Information System (INIS)

    Nuclear power plants have sought radiation source term reduction and reduced discharge of radioactive constituents for many years. In the case of pressurized water reactors (PWRs), the latter efforts have been directed toward capture and immobilization of recalcitrant (ubiquitous radionuclides with long half-lives) species such as Cs-134 and Cs-137 and Co-58 and Co-60. As these plants resolved, or at least mitigated, the problems with radiocesium and radio-cobalt, antimony radionuclides (Sb-122, Sb-124, and Sb-125) have become a primary concern in liquid liquid radwaste systems Graver Technologies developed a granular composite metal oxide media with good selectivity for radio-antimony. Initial laboratory data were collected using non-radioactive salts of antimony, cesium, and cobalt to judge efficacy of selective removal of antimony. Based on success of those trials, the media, designated Gravex GX187, was tested in partnership with Energy Solutions (nee Duratek) using actual liquid liquid radwaste in two PWR plants. One of these plants performed extensive slip-stream trials comparing the GX187 with strong base anion resins. With more than 2500 bed volumes of throughput, the GX187 outperformed the other competitors by reducing both Sb-124 and Sb-125 radionuclides below minimum detectable activity (MDA) with average decontamination factors (DF's) of 170, even when subjected to high levels of borate. Based on these favorable results, Energy Solutions installed the GX187 in a layered bed in their ALPS liquid radwaste processing system at this plant in August 2005. After one year of intermittent, batchwise operation including an outage, the GX187 processed more than 2.25 million liters (>600,000 gallons) of liquid liquid radwaste while reducing the Sb-125 activity to 2.9 E-08 Bq/L (DF=111) on average. This evaluation is ongoing and will continue at least until the fall 2006 outage at this plant. Concurrently, Graver developed a second generation antimony selective

  19. Characterization of cold-sprayed nanostructured Fe-based alloy

    International Nuclear Information System (INIS)

    The ball-milled Fe-Si alloy was used as feedstock for deposition of nanocrystalline Fe-Si by cold spraying process. The microstructure of the as-sprayed nanostructured Fe-Si was characterized by using optical microscopy, scanning electron microscopy and transmission electron microscopy. The grain sizes of the feedstock and as-sprayed deposit were estimated based on X-ray diffraction analysis. The microhardness and coercivity of the deposited Fe-Si alloy were characterized. The results showed that the as-sprayed deposit presented a dense microstructure. The mean grain size of the as-deposited Fe-Si was several tens nanometers and comparable to that of the corresponding milled feedstock. The temperature of driving gas presented little effect on the microstructure of cold-sprayed nanostructured Fe-Si deposit. The mechanical alloying induced oxygen contents up to 8 wt% in the feedstocks and subsequent deposits. The microhardness of the deposit reached about 400 Hv. The deposit achieved a high coercivity up to 190 kA/m indicating the potential possibility for applications to recording materials.

  20. Investigation of solidification dynamics of Zr-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kobold, Raphael; Herlach, Dieter [Institut fuer Materialphysik im Weltraum, Deutsches Zentrum fuer Luft- und Raumfahrt, 51170 Koeln (Germany); Ruhr-Universitaet Bochum, 44780 Bochum (Germany)

    2013-07-01

    In contrast to experiments with most undercooled binary alloys the velocity of dendritic growth of a Cu50Zr50 alloy does not increase monotonically with undercooling but passes through a maximum and then decreases. To study this behaviour we investigate Zr-based alloys such as CuZr, NiZr and NiZrAl with Zirconium concentrations ranging from 36 to 64 at.% including eutectic and intermetallic phases. We use electrostatic levitation technique to melt and undercool samples with a diameter of 2-3 mm under ultra-high-vacuum conditions. Containerless processing is an effective tool for undercooling metallic melts far below their equilibrium melting temperatures since heterogeneous nucleation on container walls is completely avoided. During crystallisation of the undercooled melt the heat of crystallisation is released. The rapid increase of the temperature at the solid-liquid interface makes the solidification front visible. The velocities of the solidification front are recorded by using a high-speed camera with a maximum rate of 50.000 frames per second and are analyzed with a software for optical ray tracing. Furthermore, we try to model the growth velocity vs. the undercooling temperature and perform sample EBSD analysis with a scanning electron microscope.

  1. Metallic ion release from biocompatible cobalt-based alloy

    Directory of Open Access Journals (Sweden)

    Dimić Ivana D.

    2014-01-01

    Full Text Available Metallic biomaterials, which are mainly used for the damaged hard tissue replacements, are materials with high strength, excellent toughness and good wear resistance. The disadvantages of metals as implant materials are their susceptibility to corrosion, the elastic modulus mismatch between metals and human hard tissues, relatively high density and metallic ion release which can cause serious health problems. The aim of this study was to examine metallic ion release from Co-Cr-Mo alloy in artificial saliva. In that purpose, alloy samples were immersed into artificial saliva with different pH values (4.0, 5.5 and 7.5. After a certain immersion period (1, 3 and 6 weeks the concentrations of released ions were determined using Inductively Coupled Plasma - Mass Spectrophotometer (ICP-MS. The research findings were used in order to define the dependence between the concentration of released metallic ions, artificial saliva pH values and immersion time. The determined released metallic ions concentrations were compared with literature data in order to describe and better understand the phenomenon of metallic ion release from the biocompatible cobalt-based alloy. [Projekat Ministarstva nauke Republike Srbije, br. III 46010 i br. ON 174004

  2. Pack cementation diffusion coatings for iron-base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, R.A. [Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering

    1995-02-01

    With the aid of computer-assisted calculations of the equilibrium vapor pressures in halide-activated cementation packs, processing conditions have been identified and experimentally verified for the codeposition of two or more alloying elements in a diffusion coating on a variety of steels. The Cr-Si ferrite layers have proven to be very resistant to high temperature cyclic oxidation and to pitting in aqueous solutions. The process has been patented, and is being transferred for industrial application, e.g. for water walls of utility boilers, etc. In the proposed extension of this project, the use of mixed pure metal powders in the pack will be extended to achieve similar ferrite Fe-Cr-Al coatings with excellent oxidation resistance, with the eventual transfer of the technology to industry. In other recent studies, Ni-base alloy rods were aluminized by the halide-activated pack cementation process to bring their average composition to that for the ORNL-developed Ni{sub 3}Al, for use as a welding rod. A similar effort to develop a welding rod for the ORNL Fe{sub 3}Al alloy did not yield reproducible coating compositions or growth kinetics. The continued effort to produce Duriron-type (Fe-18Si-5Cr) coatings on steels was not successful. Literature for the intrinsic diffusion coefficients suggests that this task cannot be achieved.

  3. The thermal transient effect on some nickel-based alloys

    International Nuclear Information System (INIS)

    This paper studies two nickel-based alloys after thermal transient tests. Two alloys were tested, namely Inconel 617 (UNS N06617) and Haynes 230 (UNS N06230). These materials are study for to be used in the construction of the steam generators of the future NPP reactors which must operate in severe conditions (high temperature, thermo-mechanical stress, aggressive media). The experiment consisted in thermal transient tests using a few scenarios: fast heating rates (50OC/minute) up to 1,000OC, maintaining this temperature level (0-60 minutes) and slowly/fast cooling. The metallographic analysis consisted in microstructure, micro-hardness determinations and traction tests. The average grain size was determined by linear interception method. The micro hardness was calculated by the relationship from the device technical book. On the traction diagrams the following mechanic characteristics were obtained: breaking resistance (Rm), elongation at rupture (A) and elastic modulus (E). The tested alloys were compared with the received materials. (authors)

  4. Crystallization kinetics of Fe based amorphous alloy

    Science.gov (United States)

    Shanker Rao, T.; Lilly Shanker Rao, T.

    2015-02-01

    Differential Scanning Calorimetry(DSC) experimental data under non-isothermal conditions for Fe based Metglas 2605SA1 (wt% Fe=85-95, Si=5-10, B=1-5) metallic glass ribbons are reported and discussed. The DSC Scans performed at different heating rates showed two step crystallization processes and are interpreted in terms of different models like Kissinger, Ozawa, Boswell, Augis & Bennett and Gao & Wang. From the heating rate dependence of the onset temperature (To) and the crystallization peak temperature (Tp), the kinetic triplet, activation energy of crystallization (E), Avrami exponent (n) and the frequency factor (A) are determined. The determined E for peak I is 354.5 ± 2.5 kJ/mol and for the peak II is 348.2 ± 2.2 kJ/mol, respectively. The frequency factor for peak I is 1.1 × 1023sec-1 and for peak II is 6.1 × 1020sec-1.

  5. Treatment of antimony mine drainage: challenges and opportunities with special emphasis on mineral adsorption and sulfate reducing bacteria.

    Science.gov (United States)

    Li, Yongchao; Hu, Xiaoxian; Ren, Bozhi

    2016-01-01

    The present article summarizes antimony mine distribution, antimony mine drainage generation and environmental impacts, and critically analyses the remediation approach with special emphasis on iron oxidizing bacteria and sulfate reducing bacteria. Most recent research focuses on readily available low-cost adsorbents, such as minerals, wastes, and biosorbents. It is found that iron oxides prepared by chemical methods present superior adsorption ability for Sb(III) and Sb(V). However, this process is more costly and iron oxide activity can be inhibited by plenty of sulfate in antimony mine drainage. In the presence of sulfate reducing bacteria, sulfate can be reduced to sulfide and form Sb2S3 precipitates. However, dissolved oxygen and lack of nutrient source in antimony mine drainage inhibit sulfate reducing bacteria activity. Biogenetic iron oxide minerals from iron corrosion by iron-oxidizing bacteria may prove promising for antimony adsorption, while the micro-environment generated from iron corrosion by iron oxidizing bacteria may provide better growth conditions for symbiotic sulfate reducing bacteria. Finally, based on biogenetic iron oxide adsorption and sulfate reducing bacteria followed by precipitation, the paper suggests an alternative treatment for antimony mine drainage that deserves exploration. PMID:27148704

  6. Future trends of global atmospheric antimony emissions from anthropogenic activities until 2050

    Science.gov (United States)

    Zhou, Junrui; Tian, Hezhong; Zhu, Chuanyong; Hao, Jiming; Gao, Jiajia; Wang, Yong; Xue, Yifeng; Hua, Shenbin; Wang, Kun

    2015-11-01

    This paper presents the scenario forecast of global atmospheric antimony (Sb) emissions from anthropogenic activities till 2050. The projection scenarios are built based on the comprehensive global antimony emission inventory for the period 1995-2010 which is reported in our previous study. Three scenarios are set up to investigate the future changes of global antimony emissions as well as their source and region contribution characteristics. Trends of activity levels specified as 5 primary source categories are projected by combining the historical trend extrapolation with EIA International energy outlook 2013, while the source-specific dynamic emission factors are determined by applying transformed normal distribution functions. If no major changes in the efficiency of emission control are introduced and keep current air quality legislations (Current Legislation scenario), global antimony emissions will increase by a factor of 2 between 2010 and 2050. The largest increase in Sb emissions is projected from Asia due to large volume of nonferrous metals production and waste incineration. In case of enforcing the pollutant emission standards (Strengthened Control scenario), global antimony emissions in 2050 will stabilize with that of 2010. Moreover, we can anticipate further declines in Sb emissions for all continents with the best emission control performances (Maximum Feasible Technological Reduction scenario). Future antimony emissions from the top 10 largest emitting countries have also been calculated and source category contributions of increasing emissions of these countries present significant diversity. Furthermore, global emission projections in 2050 are distributed within a 1° × 1°latitude/longitude grid. East Asia, Western Europe and North America present remarkable differences in emission intensity under the three scenarios, which implies that source-and-country specific control measures are necessary to be implemented for abating Sb emissions from

  7. Leachability of antimony from energy ashes. Total contents, leachability and remedial suggestions; Lakning av antimon fraan energiaskor. Totalhalter, lakbarhet samt foerslag till aatgaerder

    Energy Technology Data Exchange (ETDEWEB)

    Baeckstroem, Mattias [Oerebro Univ. (Sweden)

    2006-01-15

    In the current project total concentrations for antimony in 31 energy ashes have been compiled. The average concentration of antimony in boiler fly ash and grate boiler fly ash is 192 and 1,140 mg/kg, respectively. The corresponding antimony concentrations for boiler ashes and grate bottom ashes are 86,5 and 61,8 mg/kg, respectively. Multivariate calculations clearly pointed out waste as the major source for antimony in ashes. The difference between total antimony concentration in fly ash and bottom ash is greatest for grate boilers, in average 18 times higher in the fly ash. The difference for CFB/BFB-boilers is only slightly more than 2. However, based on amount, 75% of the total antimony inventory is recovered in the fly ashes for both CFB/BFB and grate boilers. Eleven (eight of which were bottom ashes) out of the 31 samples exceeded the guidelines for inert waste. It is clear that the higher ionic strength in the solutions from the fly ashes contribute to decrease the solubility for critical minerals retaining antimony. In addition, the fly ashes have considerably larger effective surface able to sorb trace elements. A clear and positive covariance was discovered between aluminium and antimony. Furthermore, it was noted that antimony showed no typical anionic behaviour despite the fact that it according to the geochemical calculations should be present as SbO{sub 3}{sup -}. At L/S 10, a maximum of 1% of the total antimony concentration is leached. This should be compared to chloride that had 94% of the total concentration leached at L/S 10. There was no correlation between the leached antimony concentrations and the total antimony concentrations. The sequential extractions also suggest a low leachability for antimony from the ashes. In average only 9,6% is released at pH 7, 7,3% at pH 5, 3,6% during reducing conditions and 3,2% during oxidising conditions. In total, only 24% of the total antimony concentrations is released during the four extraction steps. The

  8. Alloy 690 in PWR type reactors; Aleaciones base niquel en condiciones de primario de los reactores tipo PWR

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Briceno, D.; Serrano, M.

    2005-07-01

    Alloy 690, used as replacement of Alloy 600 for vessel head penetration (VHP) nozzles in PWR, coexists in the primary loop with other components of Alloy 600. Alloy 690 shows an excellent resistance to primary water stress corrosion cracking, while Alloy 600 is very susceptible to this degradation mechanisms. This article analyse comparatively the PWSCC behaviour of both Ni-based alloys and associated weld metals 52/152 and 82/182. (Author)

  9. Performance of a base isolator with shape memory alloy bars

    Institute of Scientific and Technical Information of China (English)

    Fabio Casciati; Lucia Faravelli; Karim Hamdaoui

    2007-01-01

    A new and innovative base isolation device is introduced in this paper based on extensive research carried out by the authors and their co-workers.A prototype of the device was built and experimentally tested on the shaking table.The new base isolation device consists of two disks,one vertical cylinder with an upper enlargement sustained by three horizontal cantilevers,and at least three inclined shape memory alloy(SMA) bars.The role of the SMA bars is to limit the relative motion between the base and the superstructure,to dissipate energy by their super-elastic constitutive law and to guarantee the re-centring of the device.To verify the expected performance,a prototype was built and tested under sinusoidal waves of displacement of increasing frequency with different amplitudes.It is shown that the main feature of the proposed base isolation device is that for cyclic loading,the super-elastic behavior of the alloy results in wide load-displacement loops,where a large amount of energy is dissipated.

  10. The surface spin polarization of Co-based Heusler alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fetzer, Roman; Wuestenberg, Jan-Peter; Neuschwander, Sabine; Aeschlimann, Martin; Cinchetti, Mirko [University of Kaiserslautern (Germany). Department of Physics and Research Center OPTIMAS; Jourdan, Martin; Herbort, Christian; Vilanova Vidal, Enrique; Jakob, Gerhard [University of Mainz (Germany). Institute of Physics

    2010-07-01

    Co-based Heusler alloys belong mainly to the family of half-metallic ferromagnets (HMFs). The predicted full spin polarization at the Fermi level due to the minority spin band gap makes this class of materials highly interesting for application in the field of spintronics. Thus, the characterization of the surface of Co-based Heusler compounds is extremely relevant for understanding and improving the performance of Heusler-based spintronics devices, like tunnel-magnetoresistance (TMR) junctions. Using Auger electron spectroscopy (AES) and low energy spin polarized electron photoemission, we systematically studied the correlation between chemical composition and spin polarisation of the surface. For various Co-based Heusler alloys, e.g. Co{sub 2}CrAl, Co{sub 2}MnAl and Co{sub 2}FeGa{sub 0.5}Ge{sub 0.5}, we found different degrees of spin-polarization at the very surface region. Reasons for the distinct deviation from the predicted 100% spin polarization and the dependence on the specific surface preparation procedure are discussed.

  11. Chromium Activity Measurements in Nickel Based Alloys for Very High Temperature Reactors: Inconel 617, Haynes 230, and Model Alloys

    International Nuclear Information System (INIS)

    The alloys Haynes 230 and Inconel 617 are potential candidates for the intermediate heat exchangers (IHXs) of (very) high temperature reactors ((V)-HTRs). The behavior under corrosion of these alloys by the (V)-HTR coolant (impure helium) is an important selection criterion because it defines the service life of these components. At high temperature, the Haynes 230 is likely to develop a chromium oxide on the surface. This layer protects from the exchanges with the surrounding medium and thus confers certain passivity on metal. At very high temperature, the initial microstructure made up of austenitic grains and coarse intra- and intergranular M6C carbide grains rich in W will evolve. The M6C carbides remain and some M23C6 richer in Cr appear. Then, carbon can reduce the protective oxide layer. The alloy loses its protective coating and can corrode quickly. Experimental investigations were performed on these nickel based alloys under an impure helium flow (Rouillard, F., 2007, 'Mecanismes de formation et de destruction de la couche d'oxyde sur un alliage chrominoformeur en milieu HTR, Ph.D. thesis, Ecole des Mines de Saint-Etienne, France). To predict the surface reactivity of chromium under impure helium, it is necessary to determine its chemical activity in a temperature range close to the operating conditions of the heat exchangers (T approximate to 1273 K). For that, high temperature mass spectrometry measurements coupled to multiple effusion Knudsen cells are carried out on several samples: Haynes 230, Inconel 617, and model alloys 1178, 1181, and 1201. This coupling makes it possible for the thermodynamic equilibrium to be obtained between the vapor phase and the condensed phase of the sample. The measurement of the chromium ionic intensity (I) of the molecular beam resulting from a cell containing an alloy provides the values of partial pressure according to the temperature. This value is compared with that of the pure substance (Cr) at the same temperature

  12. Ferromagnetic resonance in Ni-Mn based ferromagnetic Heusler alloys

    International Nuclear Information System (INIS)

    Ferromagnetic Ni-Mn based Heusler alloys undergo martensitic transformations leading to properties such as magnetic shape memory, magnetic field induced strain and magneto-caloric effects. The occurrence of such effects are closely related to the nature of magnetic interactions around the transition. These interactions can be closely examined by the ferromagnetic resonance (FMR) technique. Here, we report on the results of FMR studies performed at various temperatures in the martensite and austenite states of powder samples and discuss the mixed nature of the magnetic interactions in the martensitic state.

  13. Design of Zr-based AB2 type hydrogen storage alloys

    Institute of Scientific and Technical Information of China (English)

    文明芬; 王秋萍; 王兴海; 翟玉春; 陈廉

    2003-01-01

    The influences of the ratio of the radius of atom A(rA)to radius of atom B(rB),electronegativity and electron number were discussed on the Laves phase formation and the characteristics of Zr-based AB2 type hydrogen storage alloy.An enthalpy model of Zr-based AB2 alloy was obtained from known data and twelve Zr-based alloys were designed to test the model.The results show that the predicted values are in good agreement with the experimental values.The model can be used for predicting enthalpy values of Zr-based hydrogen storage alloys and settles a foundation for experiments.

  14. Defect Interaction in Iron and Iron-based Alloys

    Science.gov (United States)

    Xu, Haixuan; Stocks, G. Malcolm; Stoller, Roger

    2014-03-01

    Magnetism has a profound influence on the defect properties in iron and iron-based alloys. For instance, it has been shown from first principles calculations that the helium interstitial occupies the tetrahedral site instead of octahedral site in contrast to all previous work that neglected the magnetic effects. In this study, we explore the effects of magnetism on the defect interaction, primarily interstitial-type defects, in bcc iron and Fe-Cr systems. The magnetic moment change during the interaction of two 1/2 interstitial loops in bcc iron was calculated using the ab initio locally self-consistent multiple-scattering (LSMS) method and a significant fluctuation was observed. Adding Cr significantly modifies the magnetic structure of the defects and defect interactions. In addition, the effects of magnetism on the defect energetics are evaluated. This study provides useful insights on whether magnetism can be used as a effective means to manipulate the defect evolution in iron-based structural alloys. This material is based upon work supported as part of the Center for Defect Physics, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

  15. Properties of rhenium-based master alloys prepared by powder metallurgy techniques

    Directory of Open Access Journals (Sweden)

    A. Wrona

    2010-10-01

    Full Text Available Purpose: The aim of this work was to investigate an effect of phase composition, microstructure and selected properties of the rhenium-based alloys on the conditions of their preparation by mechanical alloying followed by pressure sintering.Design/methodology/approach: The structure and mechanical and physical properties of the Re-14.0% Ni, Re-13.7% Co and Re-9.1% Fe alloys prepared from pure metal powders by mechanical alloying in a planetary mill for 10 hours followed by sintering conducted for 1 hour at the temperature of 1150°C under the pressure of 600 MPa were investigated.Findings: The mechanical alloying results in partial dissolving of alloy components into each other, whereas their structure remains unchanged, and in a decrease in average density of powders and average diameter of their particles. As a result of sintering the alloy additives almost fully pass into rhenium-based solid solution. Density and hardness of the sinter compacts and homogeneity of alloying elements distribution were higher at longer times of mechanical alloying.Research limitations/implications: The obtained results provide complementary information on the possibility of obtaining high-melting alloys by mechanical alloying and on the rate of structural transformations taking place as a result of this process.Practical implications: The obtained materials can be used as master alloys for the production of contact materials and superalloys, providing higher homogeneity of the chemical composition and microstructure of the final products.Originality/value: A new method for preparation of rhenium-based alloys by means of mechanical alloying and powder metallurgy techniques has been successfully tested.

  16. Investigation on corrosion and wear behaviors of nanoparticles reinforced Ni-based composite alloying layer

    International Nuclear Information System (INIS)

    In order to investigate the role of amorphous SiO2 particles in corrosion and wear resistance of Ni-based metal matrix composite alloying layer, the amorphous nano-SiO2 particles reinforced Ni-based composite alloying layer has been prepared by double glow plasma alloying on AISI 316L stainless steel surface, where Ni/amorphous nano-SiO2 was firstly predeposited by brush plating. The composition and microstructure of the nano-SiO2 particles reinforced Ni-based composite alloying layer were analyzed by using SEM, TEM and XRD. The results indicated that the composite alloying layer consisted of γ-phase and amorphous nano-SiO2 particles, and under alloying temperature (1000 deg. C) condition, the nano-SiO2 particles were uniformly distributed in the alloying layer and still kept the amorphous structure. The corrosion resistance of composite alloying layer was investigated by an electrochemical method in 3.5%NaCl solution. Compared with single alloying layer, the amorphous nano-SiO2 particles slightly decreased the corrosion resistance of the Ni-Cr-Mo-Cu alloying layer. X-ray photoelectron spectroscopy (XPS) revealed that the passive films formed on the composite alloying consisted of Cr2O3, MoO3, SiO2 and metallic Ni and Mo. The dry wear test results showed that the composite alloying layer had excellent friction-reduced property, and the wear weight loss of composite alloying layer was less than 60% of that of Ni-Cr-Mo-Cu alloying layer

  17. Replacement of Co-base alloy for radiation exposure reduction in the primary system of PWR

    International Nuclear Information System (INIS)

    Of numerous Co-free alloys developed to replace Co-base stellite used in valve hardfacing material, two iron-base alloys of Armacor M and Tristelle 5183 and one nickel-base alloy of Nucalloy 488 were selected as candidate Co-free alloys, and Stellite 6 was also selected as a standard hardfacing material. These four alloys were welded on 316SS substrate using TIG welding method. The first corrosion test loop of KAERI simulating the water chemistry and operation condition of the primary system of PWR was designed and fabricated. Corrosion behaviors of the above four kinds of alloys were evaluated using this test loop under the condition of 300 deg C, 1500 psi. Microstructures of weldment of these alloys were observed to identify both matrix and secondary phase in each weldment. Hardnesses of weld deposit layer including HAZ and substrate were measured using micro-Vickers hardness tester. The status on the technology of Co-base alloy replacement in valve components was reviewed with respect to the classification of valves to be replaced, the development of Co-free alloys, the application of Co-free alloys and its experiences in foreign NPPs, and the Co reduction program in domestic NPPs and industries. 18 tabs., 20 figs., 22 refs. (Author)

  18. Palladium-based dental alloys are associated with oral disease and palladium-induced immune responses

    NARCIS (Netherlands)

    J. Muris; R.J. Scheper; C.J. Kleverlaan; T. Rustemeyer; I.M.W. van Hoogstraten; M.E. von Blomberg; A.J. Feilzer

    2014-01-01

    Background Palladium (Pd) and gold (Au) based dental alloys have been associated with oral disease. Objectives This study was designed to explore possible associations between the presence of Au-based and Pd-based dental alloys, and oral lesions, systemic complaints, and specific in vivo and in vitr

  19. Effect of ternary alloying elements on microstructure and mechanical property of Nb-Si based refractory intermetallic alloy

    International Nuclear Information System (INIS)

    Microstructure and mechanical property at room temperature and at 1773 K of Nb-Si based refractory intermetallic alloys were investigated in terms of compression and fracture toughness test. Mo and V were chosen as ternary alloying elements because of their high melting points, atomic sizes smaller than Nb. Both ternary alloying elements were found to have a significant role in modifying the microstructure from dispersed structure to eutectic-like structure in Nb solid solution/Nb5Si3 intermetallic composites. The 0.2% offset yield strength at room temperature increased with increasing content of ternary elements in Nb solid solution and volume fraction of Nb5Si3. At 1773 K, Mo addition has a positive role in increasing the yield strength. On the other hand, V addition has a role in decreasing the yield strength. The fracture toughness of ternary alloys was superior to binary alloys. Details will be discussed in correlation with ternary alloying, volume fraction of constituent phase, and the microstructure. (orig.)

  20. In vitro antileishmanial properties of neutron-irradiated meglumine antimoniate

    International Nuclear Information System (INIS)

    Pentavalent antimony, as meglumine antimoniate (Glucantime) or sodium stibogluconate (Pentostam), is the main treatment for leishmaniasis, a complex of diseases caused by the protozoan Leishmania, and an endemic and neglected threat in Brazil. Despite over half a century of clinical use, their mechanism of action, toxicity and pharmacokinetic data remain unknown. The analytical methods for determination of antimony in biological systems remain complex and have low sensitivity. Radiotracer studies have a potential in pharmaceutical development. The aim of this study was to obtain a radiotracer for antimony, with suitable physical and biological properties. Meglumine antimoniate was neutron irradiated inside the IEA-R1 nuclear reactor, producing two radioisotopes 122 Sb and 124 Sb, with high radionuclidic purity and good specific activity. This compound showed the same antileishmanial activity as the native compound. The use of the radiotracers, easily created by neutron irradiation, could be an interesting tool to solve important questions in antimonial pharmacology. (author)

  1. In vitro antileishmanial properties of neutron-irradiated meglumine antimoniate

    Energy Technology Data Exchange (ETDEWEB)

    Borborema, Samanta Etel Treiger; Nascimento, Nanci do [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), SP (Brazil). Lab. de Biologia Molecular]. E-mail: samanta@usp.br; Osso Junior, Joao Alberto [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), SP (Brazil). Centro de Radiofarmacia]. E-mail: jaosso@ipen.br; Andrade Junior, Heitor Franco de [Instituto de Medicina Tropical de Sao Paulo (IMT-SP), SP (Brazil). Lab. de Protozoologia]. E-mail:hfandrad@usp.br

    2005-10-15

    Pentavalent antimony, as meglumine antimoniate (Glucantime) or sodium stibogluconate (Pentostam), is the main treatment for leishmaniasis, a complex of diseases caused by the protozoan Leishmania, and an endemic and neglected threat in Brazil. Despite over half a century of clinical use, their mechanism of action, toxicity and pharmacokinetic data remain unknown. The analytical methods for determination of antimony in biological systems remain complex and have low sensitivity. Radiotracer studies have a potential in pharmaceutical development. The aim of this study was to obtain a radiotracer for antimony, with suitable physical and biological properties. Meglumine antimoniate was neutron irradiated inside the IEA-R1 nuclear reactor, producing two radioisotopes {sup 122} Sb and {sup 124} Sb, with high radionuclidic purity and good specific activity. This compound showed the same antileishmanial activity as the native compound. The use of the radiotracers, easily created by neutron irradiation, could be an interesting tool to solve important questions in antimonial pharmacology. (author)

  2. High Energy Storage Mg-based amorphous alloys for nickel-metal hydride battery

    International Nuclear Information System (INIS)

    Full text: Mg-based hydrogen storage alloys possess very high hydrogen absorption capacity (For example, Mg2NiH4 contains 3.6 wt.% of hydrogen). Magnesium is also abundant in nature, light in weight and low in cost. As a result, magnesium alloys have become the subject of increasing research world-wide. For a long period, it was thought that Mg-based alloy-hydrogen systems needed to be operated at high temperature (over 250 deg C) and under high hydrogen pressure. However, in recent years, some research work was successfully done to improve the hydrogen absorption kinetics of Mg2Ni by mechanical grinding and alloying. Some nano and amorphous structured Mg2Ni alloys could absorb hydrogen even at room temperature. Our research results show that it is possible to use Mg2Ni-type alloys as promising materials for increasing the negative electrode capacity of Ni-MH batteries because the theoretical discharge capacity of Mg2Ni alloy is approximately 1000 mAh/g, much higher than that of the main commercial LaNi5 alloy (which has a capacity of only about 370 mAh/g). Mg-based alloy electrodes were manufactured by a powder metallurgical technique or a induction melting method followed by ball milling with Ni and/or other metal powders. The discharge capacities of the Mg-based alloy electrodes were significantly improved by ball milling. An amorphous structure is a key factor in order to achieve high discharge capacities. The figure below shows the ball milled amorphous Mg-based alloy electrodes have very high discharge capacities by comparison with crystalline Mg2Ni alloys or commercial AB5 alloy

  3. TiAu based shape memory alloys for high temperature applications

    International Nuclear Information System (INIS)

    TiAu (equiatomic) exhibits phase transformation from B2 (ordered bcc) to thermo-elastic orthorhombic B19 martensite at about 875K and thus TiAu is categorized as high temperature shape memory alloy. In this study, recent research and developments related to TiAu based high temperature shape memory alloys will be discussed in the Introduction part. Then some results of our research group related to strengthening of TiAu based high temperature shape memory alloys will be presented. Potential of TiAu based shape memory alloys for high temperature shape memory materials applications will also be discussed. (author)

  4. TiAu based shape memory alloys for high temperature applications

    International Nuclear Information System (INIS)

    TiAu (equiatomic) exhibits phase transformaion from B2 (ordered bcc) to thermo-elastic orthorhombic B19 martensite at about 875K and thus TiAu is categorized as high temperature shape memory alloy. In this study, recent research and developments related to TiAu based high temperature shape memory alloys will be discussed in the Introduction part. Then some results of our research group related to strengthening of TiAu based high temperature shape memory alloys will be presented. Potential of TiAu based shape memory alloys for high temperature shape memory materials applications will also be discussed

  5. Electronic-Structure-Based Design of Ordered Alloys

    DEFF Research Database (Denmark)

    Bligaard, Thomas; Andersson, M.P.; Jacobsen, Karsten Wedel; Skriver, Hans Lomholt; Christensen, Claus H.; Nørskov, Jens Kehlet

    2006-01-01

    We describe some recent advances in the methodology of using electronic structure calculations for materials design. The methods have been developed for the design of ordered metallic alloys and metal alloy catalysts, but the considerations we present are relevant for the atomic-scale computational...... discovery of a promising catalytic metal alloy surface with high reactivity and low cost....

  6. Smart materials based on shape memory alloys: examples from Europe

    Energy Technology Data Exchange (ETDEWEB)

    Gotthardt, R.; Scherrer, P. [Ecole Polytechnique Federale, Lausanne (Switzerland). Dept. de Physique; Stalmans, R. [Dept. of Metallurgy and Materials Engineering, Katholieke Univ. Leuven, Heverlee (Belgium)

    2000-07-01

    Shape memory alloys (SMAs) have become increasingly attractive as embedded actuators in polymers yielding adaptive composite structures. In particular, SMA-elements have been used to actively or passively control shape, elastic modules, internal stress level and damping capacity of such smart composites. In the passive approach, copper-base SMA-plates can be used as temperature-sensitive damping elements, an interesting solution to improve the vibrational behaviour of alpine skis for example. Active materials are obtained by the integration of pre-strained Ni-Ti-base thin wires in polymer matrix composites enabling control of the vibrational behaviour through the recovery-stress tuning technique. In this paper, some results of national research programmes in Belgium and Switzerland, mainly concerning the damping capacity, are shown and a new European project entitled ''adaptive composites with embedded shape memory alloy wires'' is presented in which partners from Belgium, Germany, Greece, Great Britain and Switzerland are collaborating. (orig.)

  7. In Vitro antileishmanial properties of neutron-irradiated meglumine antimoniate

    OpenAIRE

    Samanta Etel Treiger Borborema; Heitor Franco de Andrade Junior; João Alberto Osso Junior; Nanci do Nascimento

    2005-01-01

    Pentavalent antimony, as meglumine antimoniate (Glucantime® ) or sodium stibogluconate (Pentostam® ), is the main treatment for leishmaniasis, a complex of diseases caused by the protozoan Leishmania, and an endemic and neglected threat in Brazil. Despite over half a century of clinical use, their mechanism of action, toxicity and pharmacokinetic data remain unknown. The analytical methods for determination of antimony in biological systems remain complex and have low sensitivity. Radiotracer...

  8. MODELING OF NI-CR-MO BASED ALLOYS: PART II - KINETICS

    Energy Technology Data Exchange (ETDEWEB)

    Turchi, P A; Kaufman, L; Liu, Z

    2006-07-07

    The CALPHAD approach is applied to kinetic studies of phase transformations and aging of prototypes of Ni-Cr-Mo-based alloys selected for waste disposal canisters in the Yucca Mountain Project (YMP). Based on a previous study on alloy stability for several candidate alloys, the thermodynamic driving forces together with a newly developed mobility database have been used to analyze diffusion-controlled transformations in these Ni-based alloys. Results on precipitation of the Ni{sub 2}Cr-ordered phase in Ni-Cr and Ni-Cr-Mo alloys, and of the complex P- and {delta}-phases in a surrogate of Alloy 22 are presented, and the output from the modeling are compared with experimental data on aging.

  9. Effect of Alloy 625 Buffer Layer on Hardfacing of Modified 9Cr-1Mo Steel Using Nickel Base Hardfacing Alloy

    Science.gov (United States)

    Chakraborty, Gopa; Das, C. R.; Albert, S. K.; Bhaduri, A. K.; Murugesan, S.; Dasgupta, Arup

    2016-04-01

    Dashpot piston, made up of modified 9Cr-1Mo steel, is a part of diverse safety rod used for safe shutdown of a nuclear reactor. This component was hardfaced using nickel base AWS ER NiCr-B alloy and extensive cracking was experienced during direct deposition of this alloy on dashpot piston. Cracking reduced considerably and the component was successfully hardfaced by application of Inconel 625 as buffer layer prior to hardface deposition. Hence, a separate study was undertaken to investigate the role of buffer layer in reducing the cracking and on the microstructure of the hardfaced deposit. Results indicate that in the direct deposition of hardfacing alloy on modified 9Cr-1Mo steel, both heat-affected zone (HAZ) formed and the deposit layer are hard making the thickness of the hard layer formed equal to combined thickness of both HAZ and deposit. This hard layer is unable to absorb thermal stresses resulting in the cracking of the deposit. By providing a buffer layer of Alloy 625 followed by a post-weld heat treatment, HAZ formed in the modified 9Cr-1Mo steel is effectively tempered, and HAZ formed during the subsequent deposition of the hardfacing alloy over the Alloy 625 buffer layer is almost completely confined to Alloy 625, which does not harden. This reduces the cracking susceptibility of the deposit. Further, unlike in the case of direct deposition on modified 9Cr-1Mo steel, dilution of the deposit by Ni-base buffer layer does not alter the hardness of the deposit and desired hardness on the deposit surface could be achieved even with lower thickness of the deposit. This gives an option for reducing the recommended thickness of the deposit, which can also reduce the risk of cracking.

  10. Hydrogenation properties of nanostructured Ti2Ni-based alloys and nanocomposites

    Science.gov (United States)

    Balcerzak, M.; Jakubowicz, J.; Kachlicki, T.; Jurczyk, M.

    2015-04-01

    Mechanical alloying and annealing at 1023 K for 0.5 h under an argon atmosphere were used to prepare Ti2Ni-based nanocrystalline alloys and their nanocomposites. Ti2Ni alloy was chemically modified by Pd and multi-walled carbon nanotubes. An objective of the present study is to provide data on hydrogenation properties of Ti2Ni-based alloys and compounds containing Pd and/or multi-walled carbon nanotubes. Alloys and composites were characterized by X-ray diffraction, scanning electron microscopy equipped with an electron energy dispersive spectrometer, transmission electron microscopy, atomic force microscopy to evaluate phase composition, crystal structure, grain size, particle morphology and distribution of catalyst element. Hydrogenation/dehydrogenation properties and hydriding kinetics of materials were measured using a Sievert's apparatus. Hydrogenation properties of nanostructured Ti2Ni-based alloy and Ti2Ni-based nanocomposites were compared with those of the binary Ti2Ni compound. In present work we shown how mechanical alloying method and chemical modification by Pd and MWCNTs affected hydrogen storage properties of Ti2Ni alloy. The highest hydrogen capacity obtained for nanostructured Ti2Ni + Pd alloy equaled 2.1 wt.%. Up to our knowledge it is the highest hydrogen storage capacity obtained so far for Ti2Ni-based materials.

  11. Effect of Annealing on the Properties of Antimony Telluride Thin Films and Their Applications in CdTe Solar Cells

    Directory of Open Access Journals (Sweden)

    Zhouling Wang

    2014-01-01

    Full Text Available Antimony telluride alloy thin films were deposited at room temperature by using the vacuum coevaporation method. The films were annealed at different temperatures in N2 ambient, and then the compositional, structural, and electrical properties of antimony telluride thin films were characterized by X-ray fluorescence, X-ray diffraction, differential thermal analysis, and Hall measurements. The results indicate that single phase antimony telluride existed when the annealing temperature was higher than 488 K. All thin films exhibited p-type conductivity with high carrier concentrations. Cell performance was greatly improved when the antimony telluride thin films were used as the back contact layer for CdTe thin film solar cells. The dark current voltage and capacitance voltage measurements were performed to investigate the formation of the back contacts for the cells with or without Sb2Te3 buffer layers. CdTe solar cells with the buffer layers can reduce the series resistance and eliminate the reverse junction between CdTe and metal electrodes.

  12. Evaluation of different finish line designs in base metal alloys

    Directory of Open Access Journals (Sweden)

    Aghandeh R

    1999-06-01

    Full Text Available This investigation was performed according to the widespread application of base metal alloys"nand few articles published about the marginal integrity of restorations fabricated by these metals."nThree standard dies of a maxillary first premolar were prepared with a flat shoulder finish line in buccal"naspect and chamfer in palatal. One of them left with no change. On the buccal aspect of the second and"nthird dies 135?and 1607 bevel were added respectively"nUsing dual wax technique, nine wax patterns were formed on each die and casting procedure of selected"nnon precious alloy was performed by centrifugal method. Marginal gaps of each copping seated on dies"nwere measured by scanning electron microscope (SEM with X500 magnification. Measurements were"ndone on three areas of marked dies on buccal aspect. Measurement son palatal aspect was done on"nmarked midpalatal point as control."nResults and statistical analysis showed no significant difference among marginal gaps in lingual aspect."nBut on the buccal aspect there were statistically significant differences among the groups (P<0.001. Flat"nshoulder had the best marginal integrity (mean 4 micron. Shoulder with 160' bevel had the most marginal"ngap (mean 26.5 micron and shoulder with 1357 bevel was between two other groups (mean 15.7 micron.

  13. 'Age-hardened alloy' based on bulk polycrystalline oxide ceramic

    Science.gov (United States)

    Gurnani, Luv; Singh, Mahesh Kumar; Bhargava, Parag; Mukhopadhyay, Amartya

    2015-05-01

    We report here for the first time the development of 'age-hardened/toughened' ceramic alloy based on MgO in the bulk polycrystalline form. This route allows for the facile development of a 'near-ideal' microstructure characterized by the presence of nanosized and uniformly dispersed second-phase particles (MgFe2O4) within the matrix grains, as well as along the matrix grain boundaries, in a controlled manner. Furthermore, the intragranular second-phase particles are rendered coherent with the matrix (MgO). Development of such microstructural features for two-phase bulk polycrystalline ceramics is extremely challenging following the powder metallurgical route usually adopted for the development of bulk ceramic nanocomposites. Furthermore, unlike for the case of ceramic nanocomposites, the route adopted here does not necessitate the usage of nano-powder, pressure/electric field-assisted sintering techniques and inert/reducing atmosphere. The as-developed bulk polycrystalline MgO-MgFe2O4 alloys possess considerably improved hardness (by ~52%) and indentation toughness (by ~35%), as compared to phase pure MgO.

  14. A Shape Memory Alloy Based Cryogenic Thermal Conduction Switch

    Science.gov (United States)

    Notardonato, W. U.; Krishnan, V. B.; Singh, J. D.; Woodruff, T. R.; Vaidyanathan, R.

    2005-01-01

    Shape memory alloys (SMAs) can produce large strains when deformed (e.g., up to 8%). Heating results in a phase transformation and associated recovery of all the accumulated strain. This strain recovery can occur against large forces, resulting in their use as actuators. Thus an SMA element can integrate both sensory and actuation functions, by inherently sensing a change in temperature and actuating by undergoing a shape change as a result of a temperature-induced phase transformation. Two aspects of our work on cryogenic SMAs are addressed here. First - a shape memory alloy based cryogenic thermal conduction switch for operation between dewars of liquid methane and liquid oxygen in a common bulkhead arrangement is discussed. Such a switch integrates the sensor element and the actuator element and can be used to create a variable thermal sink to other cryogenic tanks for liquefaction, densification, and zero boil-off systems for advanced spaceport applications. Second - fabrication via arc-melting and subsequent materials testing of SMAs with cryogenic transformation temperatures for use in the aforementioned switch is discussed.

  15. Hydrogen determinations in a zirconium based alloy with a DSC

    International Nuclear Information System (INIS)

    In the present work a method to measure hydrogen concentrations in zirconium-based alloys was developed measuring simultaneously both, the temperature of terminal solid solubility, TTSSd, and the hydride dissolution heat, Qδ->α, using a differential scanning calorimeter (DSC). The hydrogen concentration measured with that technique, [H]Q, and the values obtained with a standard hydrogen gas meter, [H]HGM, shows a linear relation: [H]Q=(1.00+/-0.03)[H]HGM|+(9.2+/-8.0) with a correlation factor of 0.99 in the entire solubility interval in the αZr phase, from 15 to 650wt.ppm-H. The mean enthalpy value determined with two different criteria for TTSSd and Qδ->α measurements is ΔHδ->α(Q)=39.3+/-1.5kJ/mol H. The present method is specially appropriate for alloys where a partition of the overall hydrogen concentration in two phases exists. It is applicable to all hydride forming metals which ideally follows the van't Hoff law

  16. Rational design of Nb-based alloys for hydrogen separation: A first principles study

    OpenAIRE

    Byungki Ryu; Hyeon Cheol Park; Eunseog Cho; Kwanghee Kim; Jaeho Lee; Meilin Liu

    2013-01-01

    We have investigated the effect of alloying metal elements on hydrogen solubility and mechanical integrity of Nb-based alloys, Nb15M1 (where M = Ca–Zn, Ge), using first principles-based calculations. In general, the chemical interaction between the interstitial H and metal is weakened as the alloying element is changed from an early to a late transition metal, leading to lower H solubility and higher resistance to H embrittlement. This effect becomes more pronounced when a smaller alloying el...

  17. Relationship between phase composition and corrosion resistanceof Ni-Ti-Nb based shape memory alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The stability and microstructure of Ni-Ti-Nb based shape memory alloys were investigated after alloyed with elements Zr, Cr and V. In artificial seawater (3.5%NaCl) and physiological solution (5%NaCl+0.1%H2O2), the results show that the alloying elements influence the corrosion behavior of Ni-Ti-Nb alloys. Generally, Zr improves the corrosion resistance of Ni-Ti-Nb alloy, Cr reduces its corrosion resistance and V does not change the property. In order to investigate the reason of the difference,the relation of the phase components and corrosion resistance of Ni-Ti-Nb based shape memory alloys were studied by element analysis and SEM.

  18. Wear and isothermal oxidation kinetics of nitrided TiAl based alloys

    Institute of Scientific and Technical Information of China (English)

    赵斌; 吴建生; 孙坚

    2002-01-01

    Gas nitridation of TiAl based alloys in an ammonia atmosphere was c arried out. The evaluation of the surface wear resistance was performed to compare with those of the non-nitrided alloys. It is concluded that high temperature nitridation raised wear resistance of TiAl based alloys markedly. The tribol ogical behaviors of the nitrided alloys were also discussed. The oxidation kinetics of the nitrided TiAl based alloys were investigated at 800~1000 ℃ in hot air. It is concluded that nitridation is detrimental to the oxidation resistance of TiAl based alloys under the present conditions. The nitrided alloys exhibit increased oxidizing rate with the prolongation of nitridation time at 800 ℃. However, alloys nitrided at 940 ℃ for 50 hdisplay a sign of better oxidat ion resistance than the other nitrided alloys at more severe oxidizing conditions. The parabolic rate law is considered as the basis of the data processing and interpretation of the mass gainvs time data. As a comparison with it, attempts were made to fit the data with the power law. The oxidation kinetic parameter kn, kp and n were measured and the trends were discussed.

  19. CO2 laser beam welding of AM60 magnesium-based alloy

    OpenAIRE

    BELHADJ, Asma; MASSE, Jean-Eric; Barrallier, Laurent; BOUHAFS, Mahmoud; BESSROUR, Jamel

    2010-01-01

    Magnesium alloys have a 33% lower density than aluminum alloys, whereas they exhibit the same mechanical characteristics. Their application increases in many economic sectors, in particular, in aeronautic and automotive industries. Nevertheless, their assembly with welding techniques still remains to be developed. In this paper, we present a CO2 laser welding investigation of AM60 magnesium-based alloy. Welding parameters range is determinate for the joining of 3 mm thickness sheets. The effe...

  20. Maintenance of Ni-based alloy at PWR plant

    International Nuclear Information System (INIS)

    Kansai Electric owns 11 PWR plants. At our PWR plants, we are taking various preventive maintenance measures on Ni-based alloy according to the prediction of possible trouble while past trouble occurred at overseas plants due to Primary Water Stress Corrosion Cracking (PWSCC) being considered. In addition, we are making an effort to put new maintenance techniques into practical use by conducting demonstration tests to confirm their applicability to actual plants. We have replaced reactor vessel heads at 7 plants with new ones. At the other 4 plants, we took, measures to reduce the temperature of reactor vessel head top to delay the timing of PWSCC occurrence. We are carrying out the constant load tests to predict the timing of PWSCC occurrence at these 4 plants. It is planned to conduct non-destructive inspections at an appropriate timing based on the result of the prediction. Based on the prediction of the timing of PWSCC occurrence at bottom-mounted instrumentation (BMI), we have developed water jet peening (WJP) technique to reduce residual stress and applied the technique to our plants successively. Meanwhile, a technique to cut and eliminate cracking has been developed. In addition, capping technique, which covers overall the concerned nozzle on the outer surface of the reactor vessel, has been also established. For alloy 132/82 weld metal for the connection, we are conducting ultrasonic inspection at our plants successively. In order to prepare against PWSCC occurrence, we have also established a technique to replace the entire section of concerned short piping with new one. (author)

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

    International Nuclear Information System (INIS)

    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.

  2. Mechanical and microstructural characterization of the nickel base alloy (Alloy 600) after heat treatment

    International Nuclear Information System (INIS)

    The characterization of microstructural and mechanical properties of cold rolled and heat treated alloys 600 made in Brazil were investigated. The recovery and recrystallization behavior as well as solubilization and aging have been studied using optical, scanning electron and transmission electron microscopy. Microhardness and tensile testing have been carried out. The recovery process of the cold rolled alloy 600 occurred until 600 deg C and the recrystallization stage was situated between 600 and 850 deg C. The primary recrystallization temperature was obtained at 850 deg C after 1 hour (isochronal heat treatments). The aged alloy 600 shows carbide precipitation on grains bu with ductility maintenance. (author)

  3. On the role of alloying elements in the formation of serrated grain boundaries in Ni-based alloys

    International Nuclear Information System (INIS)

    Ni-based model alloys were used to study the effect of alloying elements, namely Cr, Mo, C and Zr on the occurrence of grain boundary serration. The model alloys were free of aluminum to exclude precipitation of second-phase γ'. Similarly, the carbon content was very low, when present, to prevent precipitation of carbides. A special heat treatment involving slow cooling was used to promote grain boundary serration. No significant sign of serration was observed for Ni-10Cr-10Mo, Ni-20Cr-10Mo and Ni-10Cr-10Mo-0.05C model alloys. However, substantial serration was observed for Ni-10Cr-10Mo-0.5Zr and Ni-20Cr-0.5Zr model alloys. Serrated grain boundaries were observed in the absence of either γ' or carbides. Zirconium-rich precipitates were recognized at serrated grain boundaries though their involvement in the occurrence of serration was doubtful. A mechanism of grain boundary serration formation is proposed.

  4. On the role of alloying elements in the formation of serrated grain boundaries in Ni-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Terner, Mathieu; Hong, Hyun-Uk; Lee, Je-Hyun [Changwon National Univ. (Korea, Republic of). Dept. of Materials Science and Engineering; Choi, Baig-Gyu [Korea Institute of Materials Science, Changwon (Korea, Republic of). High Temperature Materials Group

    2016-03-15

    Ni-based model alloys were used to study the effect of alloying elements, namely Cr, Mo, C and Zr on the occurrence of grain boundary serration. The model alloys were free of aluminum to exclude precipitation of second-phase γ'. Similarly, the carbon content was very low, when present, to prevent precipitation of carbides. A special heat treatment involving slow cooling was used to promote grain boundary serration. No significant sign of serration was observed for Ni-10Cr-10Mo, Ni-20Cr-10Mo and Ni-10Cr-10Mo-0.05C model alloys. However, substantial serration was observed for Ni-10Cr-10Mo-0.5Zr and Ni-20Cr-0.5Zr model alloys. Serrated grain boundaries were observed in the absence of either γ' or carbides. Zirconium-rich precipitates were recognized at serrated grain boundaries though their involvement in the occurrence of serration was doubtful. A mechanism of grain boundary serration formation is proposed.

  5. Effects of neutron irradiation on deformation behavior of nickel-base fastener alloys

    International Nuclear Information System (INIS)

    This paper presents the effects of neutron irradiation on the fracture behavior and deformation microstructure of high-strength nickel-base alloy fastener materials, Alloy X-750 and Alloy 625. Alloy X-750 in the HTH condition, and Alloy 625 in the direct aged condition were irradiated to a fluence of 2.4x1020 n/cm2 at 264 C in the Advanced Test Reactor. Deformation structures at low strains were examined. It was previously shown that Alloy X-750 undergoes hardening, a significant degradation in ductility and an increase in intergranular fracture. In contrast, Alloy 625 had shown softening with a concomitant increase in ductility and transgranular failure after irradiation. The deformation microstructures of the two alloys were also different. Alloy X-750 deformed by a planar slip mechanism with fine microcracks forming at the intersections of slip bands with grain boundaries. Alloy 625 showed much more homogeneous deformation with fine, closely spaced slip bands and an absence of microcracks. The mechanism(s) of irradiation assisted stress corrosion cracking (IASCC) are discussed

  6. Effects of neutron irradiation on deformation behavior of nickel-base fastener alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bajaj, R.; Mills, W.J.; Kammenzind, B.F.; Burke, M.G.

    1999-07-01

    This paper presents the effects of neutron irradiation on the fracture behavior and deformation microstructure of high-strength nickel-base alloy fastener materials, Alloy X-750 and Alloy 625. Alloy X-750 in the HTH condition, and Alloy 625 in the direct aged condition were irradiated to a fluence of 2.4x10{sup 20} n/cm{sup 2} at 264 C in the Advanced Test Reactor. Deformation structures at low strains were examined. It was previously shown that Alloy X-750 undergoes hardening, a significant degradation in ductility and an increase in intergranular fracture. In contrast, Alloy 625 had shown softening with a concomitant increase in ductility and transgranular failure after irradiation. The deformation microstructures of the two alloys were also different. Alloy X-750 deformed by a planar slip mechanism with fine microcracks forming at the intersections of slip bands with grain boundaries. Alloy 625 showed much more homogeneous deformation with fine, closely spaced slip bands and an absence of microcracks. The mechanism(s) of irradiation assisted stress corrosion cracking (IASCC) are discussed.

  7. Phases stability of shape memory alloys Cu based under irradiation

    International Nuclear Information System (INIS)

    The effects of irradiation on the relative phase stability of phases related by a martensitic transformation in copper based shape memory alloys were studied in this work.Different kind of particles and energies were employed in the irradiation experiments.The first kind of irradiation was performed with 2,6 MeV electrons, the second one with 170 keV and 300 keV Cu ions and the third one with swift heavy ions (Kr, Xe, Au) with energies between 200 and 600 MeV.Stabilization of the 18 R martensite in Cu-Zn-Al-Ni induced by electron irradiation was studied.The results were compared to those of the stabilization induced by quenching and ageing in the same alloy, and the ones obtained by irradiation in 18 R-Cu-Zn-Al alloys.The effects of Cu irradiation over b phase were analyzed with several electron microscopy techniques including: scanning electron microscopy (S E M), high resolution electron microscopy (H R E M), micro diffraction and X-ray energy dispersive spectroscopy (E D S). Structural changes in Cu-Zn-Al b phase into a closed packed structure were induced by Cu ion implantation.The closed packed structures depend on the irradiation fluence.Based on these results, the interface between these structures (closed packed and b) and the stability of disordered phases were analyzed. It was also compared the evolution of long range order in the Cu-Zn-Al and in the Cu-Zn-Al-Ni b phase as a function of fluence.The evolution of the g phase was also compared. Both results were discussed in terms of the mobility of irradiation induced point defects.Finally, the effects induced by swift heavy ions in b phase and 18 R martensite were studied. The results of the irradiation in b phase were qualitatively similar to those produced by irradiation with lower energies. On the contrary, nano metric defects were found in the irradiated 18 R martensite.These defects were characterized by H R E M.The characteristic contrast of the defects was associated to a local change in the

  8. Elevated temperature fretting fatigue of nickel based alloys

    Science.gov (United States)

    Gean, Matthew C.

    This document details the high temperature fretting fatigue of high temperature nickel based alloys common to turbine disk and blade applications. The research consists of three area of focus: Experiments are conducted to determine quantitatively the fretting fatigue lives of advanced nickel based alloys; Analytical tools are developed and used to investigate the fretting fatigue response of the material; Fractographic analysis of the experimental results is used to improve the analytical models employed in the analysis of the experiments. Sixty three fretting fatigue experiments were conducted at 649 °C using a polycrystalline Nickel specimen in contact with directionally solidified and single crystal Nickel pads. Various influences on the fretting fatigue life are investigated. Shot peened Rene' 95 had better fretting fatigue life compared to shot peened Rene' 88. Shot peening produced a 2x increase in life for Rene' 95, but only a marginal improvement in the fretting fatigue life for Rene' 88. Minor cycles in variable amplitude loading produces significant damage to the specimen. Addition of occasional overpeaks in load produces improvements in fretting fatigue life. Contact tractions and stresses are obtained through a variety of available tools. The contact tractions can be efficiently obtained for limited geometries, while FEM can provide the contact tractions for a broader class of problems, but with the cost of increased CPU requirements. Similarly, the subsurface contact stresses can be obtained using the contact tractions as a boundary condition with either a semi-analytical FFT method or FEM. It is found that to calculate contact stresses the FFT was only marginally faster than FEM. The experimental results are combined with the analysis to produce tools that are used to design against fretting fatigue. Fractographic analysis of the fracture surface indicates the nature of the fretting fatigue crack behavior. Interrupted tests were performed to analyze

  9. Laser welding of AZ61 magnesium-based alloys

    Institute of Scientific and Technical Information of China (English)

    Wang Hongying; Li Zhijun; Zhang Yihui

    2006-01-01

    Laser welding of AZ61 magnesium alloys was carried out asing a CO2 laser weldingexperimental system.The welding properties of AZ61 sheets with different thickness were investigated.The effect of processing parameters including laser power, welding speed and protection gas flow was researched.The results show that laser power and welding speed have large effect on the weld width and joint dimensions.Protection gas flow has relatively slight effect on the weld width.The property test of three typical joints indicates that microhardness and tensile strength in weld zone are higher than that of AZ61 base metal.Joints with good appearance and excellent mechanical properties can be produced using CO2 laser welding method.The microstructure with small grains in weld zone is believed to be responsible for the excellent mechanical properties of AZ61 joints.

  10. Study of superficial films and of electrochemical behaviour of some nickel base alloys and titanium base alloys in solution representation of granitic, argillaceous and salted ground waters

    International Nuclear Information System (INIS)

    The corrosion behaviour of the stainless steels 304, 316 Ti, 25Cr-20Ni-Mo-Ti, nickel base alloys Hastelloy C4, Inconel 625, Incoloy 800, Ti and Ti-0.2% Pd alloy has been studied in the aerated or deaerated solutions at 200C and 900C whose compositions are representative of interstitial ground waters: granitic or clay waters or salt brine. The electrochemical techniques used are voltametry, polarization resistance and complexe impedance measurements. Electrochemical data show the respective influence of the parameters such as temperature, solution composition and dissolved oxygen, addition of soluble species chloride, fluoride, sulfide and carbonates, on which depend the corrosion current density, the passivation and the pitting potential. The inhibition efficiency of carbonate and bicarbonate activities against pitting corrosion is determined. In clay water at 900C, Ti and Ti-Pd show very high passivation aptitude and a broad passive potential range. Alloying Pd increases cathodic overpotential and also transpassive potential. It makes the alloy less sensitive to the temperature effect. Optical Glow Discharge Spectra show three parts in the composition depth profiles of surface films on alloys. XPS and SIMS spectrometry analyses are also carried out. Electron microscopy observation shows that passive films formed on Ti and Ti-Pd alloy have amorphous structure. Analysis of the alloy constituents dissolved in solutions, by radioactivation in neutrons, gives the order of magnitude of the Ni base alloy corrosion rates in various media. It also points out the preferential dissolution of alloying iron and in certain cases of chromium

  11. Evaluation of Nb-base alloys for the divertor structure in fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Purdy, I.M. [Argonne National Laboratory, Upton, IL (United States)

    1996-04-01

    Niobium-base alloys are candidate materials for the divertor structure in fusion reactors. For this application, an alloy should resist aqueous corrosion, hydrogen embrittlement, and radiation damage and should have high thermal conductivity and low thermal expansion. Results of corrosion and embrittlement screening tests of several binary and ternary Nb alloys in high-temperature water indicated the Mb-1Zr, Nb-5MO-1Zr, and Nb-5V-1Z4 (wt %) showed sufficient promise for further investigation. These alloys, together with pure Nb and Zircaloy-4 have been exposed to high purity water containing a low concentration of dissolved oxygen (<12 ppb) at 170, 230, and 300{degrees}C for up to {approx}3200 h. Weight-change data, microstructural observations, and qualitative mechanical-property evaluation reveal that Nb-5V-1Zr is the most promising alloy at higher temperatures. Below {approx}200{degrees}C, the alloys exhibit similiar corrosion behavior.

  12. Shape Memory Alloy-Based Periodic Cellular Structures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I effort will develop and demonstrate an innovative shape memory alloy (SMA) periodic cellular structural technology. Periodic cellular structures...

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

    International Nuclear Information System (INIS)

    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 in 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. (orig.)

  14. Development and Making of New Jewellery Palladium Based Alloys at JSC "Krastsvetmet"

    Institute of Scientific and Technical Information of China (English)

    YEFIMOV V. N.; MAMONOV S. N.; SHULGIN D. R.; YELTSIN S. I.

    2012-01-01

    Complex of research and development work aimed at implementation of jewellery palladium based alloys technology has been carried out at JSC Krastsvetmet.A range of palladium alloys jewellery fabrication has been organized.Compositions of a number of jewellery palladium alloys grade 850,900,950 and 990 have been proposed,their production and application in jewellery manufacture has been organized.To produce palladium alloys induction melting in inert atmosphere and melt pouring into a copper mould has been used.The ingots heat treatment conditions,as well as semi-finished jewelry plastic deformation parameters have been determined.

  15. Lithium-antimony-lead liquid metal battery for grid-level energy storage

    Science.gov (United States)

    Wang, Kangli; Jiang, Kai; Chung, Brice; Ouchi, Takanari; Burke, Paul J.; Boysen, Dane A.; Bradwell, David J.; Kim, Hojong; Muecke, Ulrich; Sadoway, Donald R.

    2014-10-01

    The ability to store energy on the electric grid would greatly improve its efficiency and reliability while enabling the integration of intermittent renewable energy technologies (such as wind and solar) into baseload supply. Batteries have long been considered strong candidate solutions owing to their small spatial footprint, mechanical simplicity and flexibility in siting. However, the barrier to widespread adoption of batteries is their high cost. Here we describe a lithium-antimony-lead liquid metal battery that potentially meets the performance specifications for stationary energy storage applications. This Li||Sb-Pb battery comprises a liquid lithium negative electrode, a molten salt electrolyte, and a liquid antimony-lead alloy positive electrode, which self-segregate by density into three distinct layers owing to the immiscibility of the contiguous salt and metal phases. The all-liquid construction confers the advantages of higher current density, longer cycle life and simpler manufacturing of large-scale storage systems (because no membranes or separators are involved) relative to those of conventional batteries. At charge-discharge current densities of 275 milliamperes per square centimetre, the cells cycled at 450 degrees Celsius with 98 per cent Coulombic efficiency and 73 per cent round-trip energy efficiency. To provide evidence of their high power capability, the cells were discharged and charged at current densities as high as 1,000 milliamperes per square centimetre. Measured capacity loss after operation for 1,800 hours (more than 450 charge-discharge cycles at 100 per cent depth of discharge) projects retention of over 85 per cent of initial capacity after ten years of daily cycling. Our results demonstrate that alloying a high-melting-point, high-voltage metal (antimony) with a low-melting-point, low-cost metal (lead) advantageously decreases the operating temperature while maintaining a high cell voltage. Apart from the fact that this finding

  16. The exposure to and health effects of antimony

    DEFF Research Database (Denmark)

    Cooper, Ross G.; Harrison, Adrian Paul

    2009-01-01

    . Antimony toxicity is dependent on the exposure dose, duration, route (breathing, eating, drinking, or skin contact), other chemical exposures, age, sex, nutritional status, family traits, life style, and state of health. Chronic exposure to antimony in the air at levels of 9 mg/m3 may exacerbate irritation...

  17. The presence of antimony in various dental filling materials

    International Nuclear Information System (INIS)

    Antimony was determined in a number of non-metallic dental materials currently used for tooth restoration. The method applied was instrumental neutron activation analysis. The concentration of antimony in some of the brands tested was found to be as high as 900 fold that in the normal hard dental tissues. (author)

  18. Cu-based shape memory alloys with enhanced thermal stability and mechanical properties

    International Nuclear Information System (INIS)

    Cu-based shape memory alloys were developed in the 1960s. They show excellent thermoelastic martensitic transformation. However the problems in mechanical properties and thermal instability have inhibited them from becoming promising engineering alloys. A new Cu-Zn-Al-Mn-Zr Cu-based shape memory alloy has been developed. With the addition of Mn and Zr, the martensitic transformation behaviour and the grain size ca be better controlled. The new alloys demonstrates good mechanical properties with ultimate tensile strenght and ductility, being 460 MPa and 9%, respectively. Experimental results revealed that the alloy has better thermal stability, i.e. martensite stabilisation is less serious. In ordinary Cu-Zn-Al alloys, martensite stabilisation usually occurs at room temperature. The new alloy shows better thermal stability even at elevated temperature (∝150 C, >Af=80 C). A limited small amount of martensite stabilisation was observed upon ageing of the direct quenched samples as well as the step quenched samples. This implies that the thermal stability of the new alloy is less dependent on the quenching procedure. Furthermore, such minor martensite stabilisation can be removed by subsequent suitable parent phase ageing. The new alloy is ideal for engineering applications because of its better thermal stability and better mechanical properties. (orig.)

  19. An experimental study of the magnetic ordering in Pd-based Fe and Mn alloys

    International Nuclear Information System (INIS)

    This thesis presents the results of an investigation on the magnetic ordering phenomena in some Pd based alloys with small concentrations of magnetic impurities. It has been the object to explore the ordering mechanisms in these alloys which lead to various types of magnetism at low temperature. The experimental techniques used are described. (Auth.)

  20. Separation of traffic related antimony compounds

    International Nuclear Information System (INIS)

    Complete text of publication follows. It is known that most of the brake pads contain Sb2S3 as lubricant to achieve better friction stability. Due to braking the brake lining crumbles away and its Sb content gets into the air. As a result of the temperature increase accompanying the braking a part of the antimony may oxidize to oxides, as Sb2O3 or even to the more stable form, Sb2O4. Since Sb2O3 more readily soluble than the others, its absorption from the lung so its environmental impact effect is more harmful. After a systematic investigation involving solubilization of the solid compounds, citric and tartaric acid as well as 6 mol/dm3 HCl were tested for leaching of trace antimony compounds from natural matrix. To prepare reference material related to these species, soil and activated charcoal was spiked in 10 μg/g concentration with all the three material (Sb2S3, Sb2O3,Sb2O4). separately. Recovery of the different forms was checked by graphite furnace atomic absorption spectrometric (GFAAS) analysis of the leachates. The soil was confirmed to oxidize the sulfide content while the activated charcoal was established to enrich antimony from HCl solution as ion association complex. It was concluded, that Sb2S3 is leached only in slight amount in 4 hours by 0.1-0.5 mol/dm3 citric acid, while leaching of Sb2O3 is quantitative. On the other side, it was proved that Sb2O3 as well as Sb2S3 traces are soluble in 6 HCl solution in 60 min, whilst Sb2O4 is not destroyed. So, the Sb2O3 and Sb2S3 content of a flying dust can be determined. The GFAAS temperature program had to be modified in order to be capable to analyze high organic matrix as citric or tartaric acid even in 0.5 mol/dm3 concentration. Concerning their decomposition temperature an additional step was inserted into the temperature program, pyrolysis on 300 and 400 deg C, respectively. The antimony concentration of the highly acidic leachates were determined by hydride generation GFAAS. The reproducibility of

  1. Properties and Application of Iron-based Shape Memory Alloy

    Institute of Scientific and Technical Information of China (English)

    Li Jian-chen; Jiang Qing; Dai Jun

    2005-01-01

    The properties of FeMnSiCrNi shape memory alloy were investigated. The results show that the best shape memory effect of Fel4Mn6Si9Cr5Ni alloy is 85%. The transformation amount of the ε→γ transformation is not complete after heating the alloy to 1000 K, As and Af points drop with increased transformation enthalpy ( △Hγ→ε) by thermal cycling and increased prestrain. The alloy shows also good creep and stress relaxation resistance. In addition, the alloy having a tensile force of 20 kN and a sealing pressure of 6 MPa can satisfy requirements for possible industrial application on pipe joints.

  2. Mechanical Properties of Ni-base ODS Alloy Influenced by Process Variables

    International Nuclear Information System (INIS)

    According to a recent investigation, no proven industrial technology could be directly used for such applications. For example, extensive work on Alloy 617 which is the candidate material for the intermediate heat exchanger (IHX) in very high temperature reactors (VHTR) shows that Alloy 617 exhibit quite good creep properties, the maximum service temperature of Alloy 617 is much less than that required for the VHTR-IHX applications. In this regard, oxide dispersion strengthened (ODS) materials have received a great attention owing to their excellent mechanical properties at higher temperatures, e.g., creep resistance. As part of an alloy development program for nickel base ODS alloy, we have produced an ODS Alloy 617 via mechanical alloying and hot extrusion, and characterized its microstructural evolution during the process and evaluated mechanical properties at elevated temperatures. The current work reports the effects of process variables and yttria contents on the microstructure and mechanical properties of ODS Alloy 617. From the experimental work on the influences of yttria content, and process variables such as hot-extrusion ratio and hydrogen reduction on the mechanical properties of ODS Alloy 617, it is concluded that reduction of yttria contents from 0.6 wt.% to 0.45 wt.% and increasing hot extrusion ratio from 6.25:1 to 9:1 improve the ductility at elevated temperatures without the sacrifice of strength

  3. Effects of Cr and Nb contents on the susceptibility of Alloy 600 type Ni-base alloys to stress-corrosion cracking in a simulated BWR environment

    International Nuclear Information System (INIS)

    In order to discuss the effects of chromium and niobium contents on the susceptibility of Alloy 600 type nickel-base alloys to stress-corrosion cracking in the BWR primary coolant environment, a series of creviced bent-beam (CBB) tests were conducted in a high-temperature, high-purity water environment. Chromium, niobium, and titanium as alloying elements improved the resistivity to stress-corrosion cracking, whereas carbon enhanced the susceptibility to it. Alloy-chemistry-based correlations have been defined to predict the relative resistances of alloys to stress-corrosion cracking. A strong correlation was found, for several heats of alloys, between grain-boundary chromium depletion and the susceptibility to stress-corrosion cracking

  4. Strengthening mechanisms of indirect-extruded Mg–Sn based alloys at room temperature

    Directory of Open Access Journals (Sweden)

    Wei Li Cheng

    2014-12-01

    Full Text Available The strength of a material is dependent on how dislocations in its crystal lattice can be easily propagated. These dislocations create stress fields within the material depending on their intrinsic character. Generally, the following strengthening mechanisms are relevant in wrought magnesium materials tested at room temperature: fine-grain strengthening, precipitate strengthening and solid solution strengthening as well as texture strengthening. The indirect-extruded Mg–8Sn (T8 and Mg–8Sn–1Al–1Zn (TAZ811 alloys present superior tensile properties compared to the commercial AZ31 alloy extruded in the same condition. The contributions to the strengthen of Mg–Sn based alloys made by four strengthening mechanisms were calculated quantitatively based on the microstructure characteristics, physical characteristics, thermomechanical analysis and interactions of alloying elements using AZ31 alloy as benchmark.

  5. Microstructure and tensile properties of magnesium alloy modified by Si/Ca based refiner

    Institute of Scientific and Technical Information of China (English)

    DUAN Zhi-chao; SUN Yang-shan; WEI Yu; DU Wen-wen; XUE Feng; ZHU Tian-bai

    2005-01-01

    Microstructure and mechanical properties of pure magnesium and AZ31 alloy with Ca/Si based refiner addition were investigated. The results indicate that addition of Ca/Si based refiners to pure magnesium and AZ31 alloy results in remarkable microstructure refinement. With proper amount of refiner addition, the grain size in as cast ingots can be one order of magnitude lower than that without refiner addition. Small amount of refiner addition to AZ31 alloy increases both ultimate strength and yield strength significantly, while the ductility of the alloy with refiner addition is similar to that without refiner addition. Addition of refiner improves the deformability of AZ31 alloy and extruded or hot rolled specimens (rods or sheets) with refiner addition exhibit higher surface quality and mechanical properties than those without refiner addition.

  6. Scale formation on Ni-based alloys in simulated solid oxide fuel cell interconnect environments

    Energy Technology Data Exchange (ETDEWEB)

    Ziomek-Moroz, Margaret; Cramer, Stephen D.; Holcomb, Gordon R.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Singh, P. (PNNL); Windisch, C.F. (PNNL); Johnson, C.D. (NETL); Schaeffer, C. (National Energy Research Laboratory, Morgantown, WV)

    2004-11-01

    Recent publications suggest that the environment on the fuel side of the bi-polar stainless steel SOFC interconnects changes the oxidation behavior and morphology of the scale formed on the air side. The U.S. Department of Energy Albany Research Center (ARC), has examined the role of such exposure conditions on advanced nickel base alloys. Alloy formulations developed at ARC and commercial alloys were studied using X-ray diffraction (XRD) and Raman spectroscopy. The electrical property of oxide scales formed on selected alloys was determined in terms of areaspecific resistance (ASR). The corrosion behavior of ARC nickel-based alloys exposed to a dual environment of air/ H2 were compared to those of Crofer 22APU and Haynes 230.

  7. Perpendicular Magnetic Anisotropy in Co-Based Full Heusler Alloy Thin Films

    Science.gov (United States)

    Wu, Y.; Xu, X. G.; Miao, J.; Jiang, Y.

    2015-12-01

    Half-metallic Co-based full Heusler alloys have been qualified as promising functional materials in spintronic devices due to their high spin polarization. The lack of perpendicular magnetic anisotropy (PMA) is one of the biggest obstacles restricting their application in next generation ultrahigh density storage such as magnetic random access memory (MARM). How to induce the PMA in Co-based full Heusler alloy thin films has attracted much research interest of scientists. This paper presents an overview of recent progress in this research area. We hope that this paper would provide some guidance and ideas to develop highly spin-polarized Co-based Heusler alloy thin films with PMA.

  8. Detection of residual Al-base core in Ni alloy with Gd-tagging neutron radiography

    International Nuclear Information System (INIS)

    Detection of residual aluminum-base core in nickel alloy is important for manufacturing blades of an aero-engine. Because of the strong penetrability, neutrons are more effective than X-rays to detect residual material in the nickel alloy blade. In this paper, both theoretical calculation and experiments on an accelerator-based neutron source at Peking University are used to verify the feasibility of Gd-tagging neutron radiography in detecting residual aluminum-base core in the nickel alloy. The results show that the technique can achieve a sensitivity of 0.2 mg for the residual core detection. (authors)

  9. Melting, Processing, and Properties of Disordered Fe-Al and Fe-Al-C Based Alloys

    Science.gov (United States)

    Satya Prasad, V. V.; Khaple, Shivkumar; Baligidad, R. G.

    2014-09-01

    This article presents a part of the research work conducted in our laboratory to develop lightweight steels based on Fe-Al alloys containing 7 wt.% and 9 wt.% aluminum for construction of advanced lightweight ground transportation systems, such as automotive vehicles and heavy-haul truck, and for civil engineering construction, such as bridges, tunnels, and buildings. The melting and casting of sound, porosity-free ingots of Fe-Al-based alloys was accomplished by a newly developed cost-effective technique. The technique consists of using a special flux cover and proprietary charging schedule during air induction melting. These alloys were also produced using a vacuum induction melting (VIM) process for comparison purposes. The effect of aluminum (7 wt.% and 9 wt.%) on melting, processing, and properties of disordered solid solution Fe-Al alloys has been studied in detail. Fe-7 wt.% Al alloy could be produced using air induction melting with a flux cover with the properties comparable to the alloy produced through the VIM route. This material could be further processed through hot and cold working to produce sheets and thin foils. The cold-rolled and annealed sheet exhibited excellent room-temperature ductility. The role of carbon in Fe-7 wt.% Al alloys has also been examined. The results indicate that Fe-Al and Fe-Al-C alloys containing about 7 wt.% Al are potential lightweight steels.

  10. Imprecise knowledge based design and development of titanium alloys for prosthetic applications.

    Science.gov (United States)

    Datta, S; Mahfouf, M; Zhang, Q; Chattopadhyay, P P; Sultana, N

    2016-01-01

    Imprecise knowledge on the composition-processing-microstructure-property correlation of titanium alloys combined with experimental data are used for developing rule based models for predicting the strength and elastic modulus of titanium alloys. The developed models are used for designing alloys suitable for orthopedic and dental applications. Reduced Space Searching Algorithm is employed for the multi-objective optimization to find composition, processing and microstructure of titanium alloys suitable for orthopedic applications. The conflicting requirements attributes of the alloys for this particular purpose are high strength with low elastic modulus, along with adequate biocompatibility and low costs. The 'Pareto' solutions developed through multi-objective optimization show that the preferred compositions for the fulfilling the above objectives lead to β or near β-alloys. The concept of decision making employed on the solutions leads to some compositions, which should provide better combination of the required attributes. The experimental development of some of the alloys has been carried out as guided by the model-based design methodology presented in this research. Primary characterizations of the alloys show encouraging results in terms of the mechanical properties. PMID:26398780

  11. Reducing NOx emissions with antimony additive

    International Nuclear Information System (INIS)

    This paper describes improvement in a process for the catalytic cracking of a heavy hydrocarbon feed containing Ni and nitrogen compounds by contact with a circulating inventory of catalytic cracking catalyst to produce catalytically cracked products and spent catalyst. It comprises: Ni or Ni compounds and coke comprising nitrogen compounds, and wherein the spent catalyst is regenerated by contact with oxygen or an oxygen-containing gas in a catalyst regeneration zone operating at catalyst regeneration conditions to produce hot regenerated catalyst comprising Ni or Ni compounds which is recycled to catalytically crack the heavy feed and the catalyst regeneration zone produces a flue gas comprising CO, CO2 and oxides of nitrogen, NOx. The improvement comprises: adding to the circulating catalyst inventory CO combustion promoter in an amount equivalent to 0.01 to 50 wt ppm Pt to reduce the CO content of the flue gas and reducing the NOx content of the flue gas by adding to the circulating catalyst inventory a separate particle additive comprising antimony. The additive being added in an amount sufficient to reduce the production of NOx relative to operation without the additive, and wherein the additive comprises a compound of antimony which does not substantially passivate the Ni or Ni compounds present on the cracking catalyst, nor deactivate the CO combustion promoter

  12. Electronic-Structure-Based Design of Ordered Alloys

    DEFF Research Database (Denmark)

    Bligaard, Thomas; Andersson, M.P.; Jacobsen, Karsten Wedel; Skriver, Hans Lomholt; Christensen, Claus H.; Nørskov, Jens Kehlet

    2006-01-01

    We describe some recent advances in the methodology of using electronic structure calculations for materials design. The methods have been developed for the design of ordered metallic alloys and metal alloy catalysts, but the considerations we present are relevant for the atomic-scale computational...... discovery of a promising catalytic metal alloy surface with high reactivity and low cost....... design of other materials as well. A central problem is how to treat the huge number of compounds that can be envisioned by varying the concentrations and the number of the elements involved. We discuss various strategies for approaching this problem and show how one strategy has led to the computational...

  13. Formation and Corrosion Resistance of Amorphous Ti Base Alloys

    OpenAIRE

    Naka, M.; Okada, T.; T. Matsui

    1996-01-01

    Corrosion resistant amorphous Ti-B and Ti-Si alloys were prepared on various substrates by RF sputtering. The alloying of B content of 8 at% or more stabilizes the amorphous structure. The corrosion properties of Ti alloys were evaluated by measuring the polarization curves in 1N HCl. Although the addition of B to crystalline bulky Ti shifts the corrosion potentials of Ti to the less nobles of -0.5 V(SCE) or less, that of B to amorphous sputtered Ti moves the corrosion potentials to the noble...

  14. Electron-ion plasma modification of Al-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Yurii, E-mail: yufi55@mail.ru [Institute of High-Current Electronics of the Siberian Branch of the Russian Academy of Sciences, 634055, Russia, Tomsk, 2/3 Akademicheskiy Ave (Russian Federation); National Research Tomsk State University, 634050, Russia, Tomsk, 36 Lenina Str (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050, Russia, Tomsk, 30 Lenina Str (Russian Federation); Rygina, Mariya, E-mail: l-7755me@mail.ru [National Research Tomsk Polytechnic University, Tomsk, 634050, Russia, Tomsk, 30 Lenina Str (Russian Federation); Petrikova, Elizaveta, E-mail: elizmarkova@yahoo.com; Krysina, Olga, E-mail: krysina-82@mail.ru; Teresov, Anton, E-mail: tad514@sibmail.com [Institute of High-Current Electronics of the Siberian Branch of the Russian Academy of Sciences, 634055, Russia, Tomsk, 2/3 Akademicheskiy Ave (Russian Federation); National Research Tomsk State University, 634050, Russia, Tomsk, 36 Lenina Str (Russian Federation); Ivanova, Olga, E-mail: ivaov@mail.ru; Ikonnikova, Irina, E-mail: irina-ikonnikova@yandex.ru [Tomsk State University of Architecture and Building, Tomsk, 634002, Russia, Tomsk, 2 Solyanaya Sq (Russian Federation)

    2016-01-15

    The paper reports on the study where we analyzed the surface structure and strength properties of coated Al alloys modified by electron-ion plasma treatment. The Al alloys were deposited with a thin (≈0.5 μm) TiCu film coating (TiCu-Al system) and with a hard TiCuN coating (TiCuN–AlSi system) on a TRIO vacuum setup in the plasma of low-pressure arc discharges. The temperature fields and phase transformations in the film–substrate system were estimated by numerical simulation in a wide range of electron energy densities (5–30 J/cm{sup 2}) and pulse durations (50–200 μs). The calculations allowed us to determine the threshold energy density and pulse duration at which the surface structure of the irradiated Al-based systems is transformed in a single-phase state (solid or liquid) and in a two-phase state (solid plus liquid). The elemental composition, defect structure, phase state, and lattice state in the modified surface layers were examined by optical, scanning, and transmission electron microscopy, and by X-ray diffraction analysis. The mechanical characteristics of the modified layers were studied by measuring the hardness and Young’s modulus. The tribological properties of the modified layers were analyzed by measuring the wear resistance and friction coefficient. It is shown that melting and subsequent high-rate crystallization of the TiCu–Al system makes possible a multiphase Al-based surface structure with the following characteristics: crystallite size ranging within micrometer, microhardness of more than 3 times that in the specimen bulk, and wear resistance ≈1.8 times higher compared to the initial material. Electron beam irradiation of the TiCuN–AlSi system allows fusion of the coating into the substrate, thus increasing the wear resistance of the material ≈2.2 times at a surface hardness of ∼14 GPa.

  15. Electron-ion plasma modification of Al-based alloys

    International Nuclear Information System (INIS)

    The paper reports on the study where we analyzed the surface structure and strength properties of coated Al alloys modified by electron-ion plasma treatment. The Al alloys were deposited with a thin (≈0.5 μm) TiCu film coating (TiCu-Al system) and with a hard TiCuN coating (TiCuN–AlSi system) on a TRIO vacuum setup in the plasma of low-pressure arc discharges. The temperature fields and phase transformations in the film–substrate system were estimated by numerical simulation in a wide range of electron energy densities (5–30 J/cm2) and pulse durations (50–200 μs). The calculations allowed us to determine the threshold energy density and pulse duration at which the surface structure of the irradiated Al-based systems is transformed in a single-phase state (solid or liquid) and in a two-phase state (solid plus liquid). The elemental composition, defect structure, phase state, and lattice state in the modified surface layers were examined by optical, scanning, and transmission electron microscopy, and by X-ray diffraction analysis. The mechanical characteristics of the modified layers were studied by measuring the hardness and Young’s modulus. The tribological properties of the modified layers were analyzed by measuring the wear resistance and friction coefficient. It is shown that melting and subsequent high-rate crystallization of the TiCu–Al system makes possible a multiphase Al-based surface structure with the following characteristics: crystallite size ranging within micrometer, microhardness of more than 3 times that in the specimen bulk, and wear resistance ≈1.8 times higher compared to the initial material. Electron beam irradiation of the TiCuN–AlSi system allows fusion of the coating into the substrate, thus increasing the wear resistance of the material ≈2.2 times at a surface hardness of ∼14 GPa

  16. Investigation into antimony mobility in sewage sludge fermentation.

    Science.gov (United States)

    Wehmeier, Silvia; Feldmann, Jörg

    2005-12-01

    Antimony is distributed in the environment in inorganic and organic species with different solubility and mobility characters. Here we investigate the transformation of antimony in view of biomethylation during sewage sludge fermentation as a case study for an anaerobic environment. Our approach was to identify if antimony methylation follows the Challenger pathway by using isotopically enriched antimonite (123Sb(v)). The antimony source was subjected to methylation in sewage sludge, an anaerobic dominant methanogenic Archaea community. The antimony species were determined in the gas phase using cryotrapping (CT)-GC-ICP-MS, and in the medium (sewage slude) by hydride generation (HG) prior CT-GC-ICP-MS. The determined 123/121Sb isotope ratios in the volatile trimethylstibine and non-volatile methylantimony species indicated that the methylation follows the proposed methylation pathway. With this approach we were able to quantify 123Sb incorporation into monomethyl-, dimethyl- and trimethylantimony, respectively. The incorporation decreased with further methylation from 91% to 82% and 73%. Volatilisation as trimethystibine was generally lower than 0.1%, however, up to 0.8% of added antimony was found methylated to methylantimony species and mainly accumulated in the cell. Moreover, antimony biomethylation was enhanced by stimulation of the anaerobic communities of methanogenic Archaea and sulfate reducing bacteria (SRB), with the methanogens showing a higher activity. PMID:16307071

  17. Factors affecting the optical properties of Pd-free Au-Pt-based dental alloys.

    Science.gov (United States)

    Shiraishi, Takanobu; Takuma, Yasuko; Miura, Eri; Tanaka, Yasuhiro; Hisatsune, Kunihiro

    2003-12-01

    The optical properties of experimental Au-Pt-based alloys containing a small amount of In, Sn, and Zn were investigated by spectrophotometric colorimetry to extract factors affecting color of Au-Pt-based high-karat dental alloys. It was found that the optical properties of Au-Pt-based alloys are strongly affected by the number of valence electrons per atom in an alloy, namely, the electron:atom ratio, e/a. That is, by increasing the e/a-value, activities of reflection in the long-wavelength range and absorption in the short-wavelength range in the visible spectrum apparently increased. As a result, the maximum slope of the spectral reflectance curve at the absorption edge, which is located near 515 nm (approximately 2.4 eV), apparently increased with e/a-value. Due to this effect, the b*-coordinate (yellow-blue) in the CIELAB color space considerably increased and the a*-coordinate (red-green) slightly increased with e/a-value. The addition of a third element with a higher number of valence electrons to the binary Au-Pt alloy is, therefore, effective in giving a gold tinge to the parent Au-Pt alloy. This information may be useful in controlling the color of Au-Pt-based dental alloys. PMID:15348493

  18. Shape Memory Alloy-Based Periodic Cellular Structures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase II effort will continue to develop and demonstrate an innovative shape memory alloy (SMA) periodic cellular structural technology. Periodic cellular...

  19. Damping and microstructures in aged Cu-Mn based alloys

    OpenAIRE

    Heil, Joseph Patrick.

    1988-01-01

    Approved for public release; distribution is unlimited An aged high damping alloy 53Cu 45Mn-2Al was studied both microstructurally by transmission electron microscopy (TEM) and microstructurally with two different damping measurement methods. In-situ heating and cooling observations were made with TEM in order to define the recently discovered flickering phenomenon associated with it's tweed microstructure. TEM studies were also made of an aged 53.6Cu-46.4Mn binary alloy. Damping measureme...

  20. Effects of copper-based alloy on the synthesis of single-crystal diamond

    CERN Document Server

    Chen Li Xue; Ma Hong An; Jia Xiao Peng; Wakatsuki, M; Zou Guang Tian

    2002-01-01

    The catalytic effects of copper-based alloys in diamond growth have been investigated. A single crystal of diamond has been obtained by the temperature gradient method (TGM), using Cu-Mn-Co and Cu-Co alloys as catalysts. It was found that the melted Cu-Mn-Co and Cu-Co alloys show low viscosity. The eutectic temperatures of these two alloys with graphite were between 1130 and 1150 deg. C, and the temperature of the transition to diamond was over 1300 deg. C at 5.5 GPa. High-quality diamond could not be obtained in Cu-Co alloy by the TGM. Our results suggest that adding Cu to a catalyst cannot decrease the reaction temperature for diamond growth.

  1. Modification of mechanical properties and microstructure of Ni-Cr-base alloy by continuous electron irradiation

    International Nuclear Information System (INIS)

    Using the methods of transmission and scanning electron microscopy and X-ray structure analysis investigation of 40CrNiAl alloy structure-phase state after different conditions of thermomechanical treatment (TMT) and electron irradiation is carried out. Correlation of microstructure parameters of irradiated alloy with its mechanical properties is ascertained as well as morphology of structural and phase transformations in alloy at continuous electron irradiation. Simultaneous increasing of strength characteristics and plasticity of 40CrNiAl alloy after certain conditions of TMT and electron irradiation is find out, the reasons of the phenomenon is analyzed. The scientifically-based schemes of 40CrNiAl alloy TMT are developed and choice of electron irradiation conditions for optimization of its mechanical properties is substantiated

  2. Oxidation induced phase transformations and lifetime limits of chromia forming nickel base alloy 625

    OpenAIRE

    Chyrkin, Anton

    2011-01-01

    For its high creep resistance the commercial nickel-base alloy 625 relies on solid solution strengthening in combination with precipitation hardening by formation of delta-Ni3Nb and (Ni,Mo,Si)6C precipitates during high-temperature service. In oxidizing environments the alloy forms a slow growing, continuous chromia layer on the material surface which protects the alloy against rapid oxidation attack. The growth of the chromia base oxide scale results during exposure at 900–1000°C in oxidatio...

  3. Study on DC welding parameters of Al-alloy shaping based on arc-welding robot

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The Al-alloy arc-welding shaping system based on arc-welding robot is established, and the Al-alloy shaping manufacture is realized with the DC (direct current) gas metal arc welding (GMAW). The research indicates that the metal transfer type of DC GMAW, heat input and the initial temperature of the workpiece greatly affect the Al-alloy shaping based on arc welding robot. On the penetration, the weld width and the reinforcement, the influence of welding parameters is analyzed by generalized regression neural network (GRNN) fitting.

  4. Neutron scattering measurements a useful alloy development tool for the new generation high temperature alloys based Co-Re system

    Czech Academy of Sciences Publication Activity Database

    Mukherji, D.; Wehr, J.; Strunz, Pavel; Gilles, R.; Hofmann, M.; Hoelzel, M.; Roesler, J.

    München : Technische Universität München, 2012 - (Carsughi, F.; Lommatzsch, I.; Neuhaus, J.). s. 34-34 [4th User Meeting at the FRM II. 23.03.2012-23.03.2012, Garching bei München] Institutional support: RVO:61389005 Keywords : Co-Re based alloys * neutron scattering * high temeperature Subject RIV: BM - Solid Matter Physics ; Magnetism http://cdn.frm2.tum.de/fileadmin/stuff/ information /UserOffice/UM2012_Booklet_lr.pdf

  5. Alloys based on Group 5 metals for hydrogen purification membranes

    International Nuclear Information System (INIS)

    Highlights: • The Ta77Nb23 alloy showed hydrogen permeability high enough to be used in diffusion purification technology. • The Ta77Nb23 alloy has mechanical properties suitable for practical application. • The hydrogen permeability data were acquired for the alloys with no special coatings. - Abstract: Production of high-purity hydrogen is required to move to power systems with little environmental impact. The considerable part of hydrogen is suggested to be obtained by methane conversion and its separation from other hydrocarbon gases which are not involved in the energy production process (associated gas, waste gas of petrochemical industry, etc.). The aim of this study was to compare properties of low cost alloys for membranes for hydrogen purification and separation. To investigate the membranes of V53Ti26Ni21 and Ta77Nb23 (wt.%) alloys, the specific hydrogen permeability and micro hardness tests, metallography and X-ray diffraction were applied. It was concluded the Ta77Nb23 (wt.%) alloy has hydrogen permeability parameters and mechanical characteristics that make it suitable for the production of thin membranes

  6. Alloys based on Group 5 metals for hydrogen purification membranes

    Energy Technology Data Exchange (ETDEWEB)

    Kozhakhmetov, S. [Institute of High Technologies, 050012 Almaty (Kazakhstan); Sidorov, N. [Institute of Metallurgy UB RAS, 620016 Ekaterinburg (Russian Federation); Piven, V. [Saint Petersburg State University, 198504 Saint Petersburg (Russian Federation); Sipatov, I. [Institute of Metallurgy UB RAS, 620016 Ekaterinburg (Russian Federation); Gabis, I. [Saint Petersburg State University, 198504 Saint Petersburg (Russian Federation); Arinov, B. [Institute of High Technologies, 050012 Almaty (Kazakhstan)

    2015-10-05

    Highlights: • The Ta{sub 77}Nb{sub 23} alloy showed hydrogen permeability high enough to be used in diffusion purification technology. • The Ta{sub 77}Nb{sub 23} alloy has mechanical properties suitable for practical application. • The hydrogen permeability data were acquired for the alloys with no special coatings. - Abstract: Production of high-purity hydrogen is required to move to power systems with little environmental impact. The considerable part of hydrogen is suggested to be obtained by methane conversion and its separation from other hydrocarbon gases which are not involved in the energy production process (associated gas, waste gas of petrochemical industry, etc.). The aim of this study was to compare properties of low cost alloys for membranes for hydrogen purification and separation. To investigate the membranes of V{sub 53}Ti{sub 26}Ni{sub 21} and Ta{sub 77}Nb{sub 23} (wt.%) alloys, the specific hydrogen permeability and micro hardness tests, metallography and X-ray diffraction were applied. It was concluded the Ta{sub 77}Nb{sub 23} (wt.%) alloy has hydrogen permeability parameters and mechanical characteristics that make it suitable for the production of thin membranes.

  7. Transport phenomena in nanowires based on bismuth alloys

    International Nuclear Information System (INIS)

    Full text: In this work, we study the conductivity and thermopower of quantum wires (QW) based on bismuth alloys. Calculations are carried out for nanowires with degenerate and nondegenerate gas of carriers at various crystalline orientations taking into account the real band structure of Bi. We find the energy eigenvalues of holes and taking into account the nonparabolicity of the band, the energy eigenvalues for electrons. The conductivity and thermopower determined with the use of the Kubo formulae in the case when the basic mechanism of carrier scattering is assumed to be elastic acoustic-phonon scattering and on a roughness surface of QW. Dependences of kinetic coefficients on temperature, nanowire diameter and crystalline orientation are investigated. The conductivity and thermopower of a QW contains the contributions of electrons and holes. Taking into account values of carrier effective masses and other band parameters of Bi, it is possible to conclude that the contribution of holes to the conductivity of nondegenerate carriers of QWs is more less than that of electrons, which is attributed to smaller effective mass of electrons. For a semiconducting Bi QW the conductivity depends exponentially on a temperature and wire diameter. The thermopower of a semiconducting and of a semimetallic Bi QW at low temperatures can be positive and change sign in more higher temperatures. The theoretical results are close to experiment for Bi wires with diameter of 50-100 nm. (author)

  8. Deployable aerospace PV array based on amorphous silicon alloys

    Science.gov (United States)

    Hanak, Joseph J.; Walter, Lee; Dobias, David; Flaisher, Harvey

    1989-01-01

    The development of the first commercial, ultralight, flexible, deployable, PV array for aerospace applications is discussed. It is based on thin-film, amorphous silicon alloy, multijunction, solar cells deposited on a thin metal or polymer by a proprietary, roll-to-roll process. The array generates over 200 W at AM0 and is made of 20 giant cells, each 54 cm x 29 cm (1566 sq cm in area). Each cell is protected with bypass diodes. Fully encapsulated array blanket and the deployment mechanism weigh about 800 and 500 g, respectively. These data yield power per area ratio of over 60 W/sq m specific power of over 250 W/kg (4 kg/kW) for the blanket and 154 W/kg (6.5 kg/kW) for the power system. When stowed, the array is rolled up to a diameter of 7 cm and a length of 1.11 m. It is deployed quickly to its full area of 2.92 m x 1.11 m, for instant power. Potential applications include power for lightweight space vehicles, high altitude balloons, remotely piloted and tethered vehicles. These developments signal the dawning of a new age of lightweight, deployable, low-cost space arrays in the range from tens to tens of thousands of watts for near-term applications and the feasibility of multi-100 kW to MW arrays for future needs.

  9. Shape-Memory-Alloy-Based Deicing System Developed

    Science.gov (United States)

    1996-01-01

    Ice buildup on aircraft leading edge surfaces has historically been a problem. Most conventional deicing systems rely either on surface heating to melt the accreted ice or pneumatic surface inflation to mechanically debond the ice. Deicers that rely solely on surface heating require large amounts of power. Pneumatic deicers usually cannot remove thin layers of ice and lack durability. Thus, there is a need for an advanced, low-power ice protection system. As part of the NASA Small Business and Innovation Research (SBIR) program, Innovative Dynamics, Inc., developed an aircraft deicing system that utilizes the properties of Shape Memory Alloys (SMA). The SMA-based system has achieved promising improvements in energy efficiency and durability over more conventional deicers. When they are thermally activated, SMA materials change shape; this is analogous to a conventional thermal expansion. The thermal input is currently applied via conventional technology, but there are plans to implement a passive thermal input that is supplied from the energy transfer due to the formation of the ice itself. The actively powered deicer was tested in the NASA Lewis Icing Research Tunnel on a powered rotating rig in early 1995. The system showed promise, deicing both rime and glaze ice shapes as thin as 1/8 in. The first prototype SMA deicer reduced power usage by 45 percent over existing electrothermal systems. This prototype system was targeted for rotorcraft system development. However, there are current plans underway to develop a fixed-wing version of the deicer.

  10. Shape Memory Alloy (SMA)-Based Launch Lock

    Science.gov (United States)

    Badescu, Mircea; Bao, Xiaoqi; Bar-Cohen, Yoseph

    2014-01-01

    Most NASA missions require the use of a launch lock for securing moving components during the launch or securing the payload before release. A launch lock is a device used to prevent unwanted motion and secure the controlled components. The current launch locks are based on pyrotechnic, electro mechanically or NiTi driven pin pullers and they are mostly one time use mechanisms that are usually bulky and involve a relatively high mass. Generally, the use of piezoelectric actuation provides high precession nanometer accuracy but it relies on friction to generate displacement. During launch, the generated vibrations can release the normal force between the actuator components allowing shaft's free motion which could result in damage to the actuated structures or instruments. This problem is common to other linear actuators that consist of a ball screw mechanism. The authors are exploring the development of a novel launch lock mechanism that is activated by a shape memory alloy (SMA) material ring, a rigid element and an SMA ring holding flexure. The proposed design and analytical model will be described and discussed in this paper.

  11. Structural and electrical characterization of zinc oxide doped with antimony

    Directory of Open Access Journals (Sweden)

    G. Juárez Díaz

    2014-08-01

    Full Text Available In this work we report the results of structural and electrical characterization realized on zinc oxide single crystal samples with (001 orientation, which were doped with antimony. Doping was carried out by antimony thermal diffusion at 1000 °C for periods of 1 and 2 hours under nitrogen environment from a solid source formed by antimony oxide. Electrical characterization by I-V curves and Hall effect shown an increase in acceptor concentration which demonstrates that doping is effective and create holes in zinc oxide samples.

  12. Welding and mechanical properties of cast FAPY (Fe-16 at. % Al-based) alloy slabs

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.; Goodwin, G.M.; Alexander, D.J.; Howell, C.R.

    1995-08-01

    The low-aluminum-content iron-aluminum program deals with the development of a Fe-Al alloy with aluminum content such as a produce the minimum environmental effect at room temperature. The FAPY is an Fe-16 at. % Al-based alloy developed at the Oak Ridge National Laboratory as the highest aluminum-containing alloy with essentially no environmental effect. The chemical composition for FAPY in weight percent is: aluminum = 8.46, chromium = 5.50, zirconium = 0.20, carbon = 0.03, molybdenum = 2.00, yttrium = 0.10, and iron = 83.71. The cast ingots of the alloy can be hot worked by extrusion, forging, and rolling processes. The hot- worked cast structure can be cold worked with intermediate anneals at 800{degrees}C. Typical room-temperature ductility of the fine-grained wrought structure is 20 to 25% for this alloy. In contrast to the wrought structure, the cast ductility at room temperature is approximately 1% with a transition temperature of approximately 100 to 150{degrees}C, above which ductility values exceed 20%. The alloy has been melted and processed into bar, sheet, and foil. The alloy has also been cast into slabs, step-blocks of varying thicknesses, and shapes. The purpose of this section is to describe the welding response of cast slabs of three different thicknesses of FAPY alloy. Tensile, creep, and Charpy-impact data of the welded plates are also presented.

  13. The Importance of Rare-Earth Additions in Zr-Based AB2 Metal Hydride Alloys

    Directory of Open Access Journals (Sweden)

    Kwo-Hsiung Young

    2016-07-01

    Full Text Available Effects of substitutions of rare earth (RE elements (Y, La, Ce, and Nd to the Zr-based AB2 multi-phase metal hydride (MH alloys on the structure, gaseous phase hydrogen storage (H-storage, and electrochemical properties were studied and compared. Solubilities of the RE atoms in the main Laves phases (C14 and C15 are very low, and therefore the main contributions of the RE additives are through the formation of the RENi phase and change in TiNi phase abundance. Both the RENi and TiNi phases are found to facilitate the bulk diffusion of hydrogen but impede the surface reaction. The former is very effective in improving the activation behaviors. −40 °C performances of the Ce-doped alloys are slightly better than the Nd-doped alloys but not as good as those of the La-doped alloys, which gained the improvement through a different mechanism. While the improvement in ultra-low-temperature performance of the Ce-containing alloys can be associated with a larger amount of metallic Ni-clusters embedded in the surface oxide, the improvement in the La-containing alloys originates from the clean alloy/oxide interface as shown in an earlier transmission electron microscopy study. Overall, the substitution of 1 at% Ce to partially replace Zr gives the best electrochemical performances (capacity, rate, and activation and is recommended for all the AB2 MH alloys for electrochemical applications.

  14. Atomic-scale properties of Ni-based FCC ternary, and quaternary alloys

    International Nuclear Information System (INIS)

    The aim of this study is to characterize some atomic-scale properties of Ni-based FCC multicomponent alloys. For this purpose, we use Monte Carlo method combined with density functional theory calculations to study short-range order (SRO), atomic displacements, electronic density of states, and magnetic moments in equimolar ternary NiCrCo, and quaternary NiCrCoFe alloys. According to our study, the salient features for the ternary alloy are a negative SRO parameter between Ni–Cr and a positive between Cr–Cr pairs as well as a weakly magnetic state. For the quaternary alloy we predict negative SRO parameter for Ni–Cr and Ni–Fe pairs and positive for Cr–Cr and Fe–Fe pairs. Atomic displacements for both ternary and quaternary alloys are negligible. In contrast to the ternary, the quaternary alloy shows a complex magnetic structure. The electronic structure of the ternary and quaternary alloys shows differences near the Fermi energy between a random solid solution and the predicted structure with SRO. Despite that, the calculated EXAFS spectra does not show enough contrast to discriminate between random and ordered structures. The predicted SRO has an impact on point-defect energetics, electron–phonon coupling and thermodynamic functions and thus, SRO should not be neglected when studying properties of these two alloys

  15. Advanced oxidation-resistant iron-based alloys for LWR fuel cladding

    Science.gov (United States)

    Terrani, K. A.; Zinkle, S. J.; Snead, L. L.

    2014-05-01

    Application of advanced oxidation-resistant iron alloys as light water reactor fuel cladding is proposed. The motivations are based on specific limitations associated with zirconium alloys, currently used as fuel cladding, under design-basis and beyond-design-basis accident scenarios. Using a simplified methodology, gains in safety margins under severe accidents upon transition to advanced oxidation-resistant iron alloys as fuel cladding are showcased. Oxidation behavior, mechanical properties, and irradiation effects of advanced iron alloys are briefly reviewed and compared to zirconium alloys as well as historic austenitic stainless steel cladding materials. Neutronic characteristics of iron-alloy-clad fuel bundles are determined and fed into a simple economic model to estimate the impact on nuclear electricity production cost. Prior experience with steel cladding is combined with the current understanding of the mechanical properties and irradiation behavior of advanced iron alloys to identify a combination of cladding thickness reduction and fuel enrichment increase (∼0.5%) as an efficient route to offset any penalties in cycle length, due to higher neutron absorption in the iron alloy cladding, with modest impact on the economics.

  16. Nanometric Antimony Powder Synthesis by Activated Alkaline Hydride Reduction of Antimony Pentachloride

    International Nuclear Information System (INIS)

    A novel chemical reduction method using an activated alkaline hydride (LiH or NaH-t-BuONa) in tetrahydrofuran solvent has been applied to antimony salt reduction. X-ray diffraction and transmission electron microscopy studies have been carried out to characterize the morphology and structure of the materials. Alkali hydride nature influence has been proved. In both cases the process allows to prepare antimony particles in nanometer range from few nanometers to about 20nm which could be used as anodic materials for lithium-ion batteries. With lithium hydride well-crystallized particles inclined to agglomeration were observed whereas finely dispersed amorphous particles were pointing out after activated sodium hydride reduction

  17. Deposition of rod-shaped antimony sulfide thin films from single-source antimony thiosemicarbazone precursors

    Energy Technology Data Exchange (ETDEWEB)

    Biswal, Jasmine B.; Sawant, Narayan V. [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai - 400 098 (India); Garje, Shivram S., E-mail: ssgarje@chem.mu.ac.i [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai - 400 098 (India)

    2010-04-02

    Antimony sulfide thin films were deposited on glass substrates by aerosol assisted chemical vapour deposition technique using single source precursors, namely, antimony(III) thiosemicarbazones, SbCl{sub 3}(L) (L = thiosemicarbazones of thiophene-2-carboxaldehyde (1) and cinnamaldehyde (2)). The deposited films were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and UV-visible spectroscopy in order to identify their phases, morphologies, compositions and optical properties respectively. These characterizations revealed that the films were comprised of rod-shaped particles of orthorhombic stibnite (Sb{sub 2}S{sub 3}) with a Sb:S stoichiometry of {approx} 1:1.3. The calculated optical band gap from UV-vis absorption spectrum is found to be 3.48 eV.

  18. Antimony mobility in Japanese agricultural soils and the factors affecting antimony sorption behavior

    International Nuclear Information System (INIS)

    The mobility of antimony (Sb) in Japanese agricultural soils was studied by radiotracer experiments using 124Sb tracer. The soil-solution distribution coefficients (K d) of Sb were measured for 110 soil samples. These K ds ranged from 1 to 2065 L kg-1; the geometric mean was 62 L kg-1 excluding one extremely high value, 2065 L kg-1. Experimental measurement of K d showed a decrease with both increasing pH and increasing phosphate concentration. The latter suggested that one aspect of the Sb sorption phenomena in Japanese soil was influenced by specific adsorption of anions such as phosphate. However, other aspects could not be explained by this specific adsorption mechanism, because only 20-40% of soil-sorbed Sb could be extracted by phosphate solution. - Antimony mobility in tested Japanese agricultural soils was generally low and was affected by pH and phosphate concentration

  19. Selective determination of antimony(III) and antimony(V) with ammonium pyrrolidinedithiocarbamate, sodium diethyldithiocarbamate and dithizone by atomic-absorption spectrometry with a carbon-tube atomizer.

    Science.gov (United States)

    Kamada, T; Yamamoto, Y

    1977-05-01

    The extraction behaviour of antimony(III) and antimony(V) with ammonium pyrrolidinedithiocarbamate, sodium diethyldithiocarbamate and dithizone in organic solvents has been investigated by means of frameless atomic-absorption spectrophotometry with a carbon-tube atomizer. The selective extraction of antimony(III) and differential determination of antimony(III) and antimony(V) have been developed. With ammonium pyrrolidinedithiocarbamate and methyl isobutyl ketone, when the aqueous phase/solvent volume ratio is 50 ml/10 ml and the injection volume in the carbon tube is 20 mul, the sensitivity for antimony is 0.2 ng/ml for 1% absorption. The relative standard deviations are ca. 2%. Interferences by many metal ions can be prevented by masking with EDTA. The proposed methods have been applied satisfactorily to determination of antimony(III) and antimony(V) in various types of water. PMID:18962096

  20. Thermodynamic Prediction of Compositional Phases Confirmed by Transmission Electron Microscopy on Tantalum-Based Alloy Weldments

    International Nuclear Information System (INIS)

    Tantalum alloys have been used by the U.S. Department of Energy as structural alloys for radioisotope based thermal to electrical power systems since the 1960s. Tantalum alloys are attractive for high temperature structural applications due to their high melting point, excellent formability, good thermal conductivity, good ductility (even at low temperatures), corrosion resistance, and weldability. Tantalum alloys have demonstrated sufficient high-temperature toughness to survive prolonged exposure to the radioisotope power-system working environment. Typically, the fabrication of power systems requires the welding of various components including the structural members made of tantalum alloys. Issues such as thermodynamics, lattice structure, weld pool dynamics, material purity and contamination, and welding atmosphere purity all potentially confound the understanding of the differences between the weldment properties of the different tantalum-based alloys. The objective of this paper is to outline the thermodynamically favorable material phases in tantalum alloys, with and without small amounts of hafnium, during and following solidification, based on the results derived from the FactSage(c) Integrated Thermodynamic Databank. In addition, Transition Electron Microscopy (TEM) data will show for the first time, the changes occurring in the HfC before and after welding, and the data will elucidate the role HfC plays in pinning grain boundaries

  1. Antimony distribution and environmental mobility at an historic antimony smelter site, New Zealand

    International Nuclear Information System (INIS)

    A historic antimony smelter site at Endeavour Inlet, New Zealand has smelter residues with up to 17 wt.% antimony. Residues include coarse tailings (cm scale particles, poorly sorted), sand tailings (well sorted) and smelter slag (blocks up to 30 cm across). All of this material has oxidised to some degree over the ca. 100 years since the site was abandoned. Oxidation has resulted in acidification of the residues down to pH 2-5. Smelter slag contains pyrrhotite (FeS) and metallic antimony, and oxidation is restricted to surfaces only. The coarse tailings are the most oxidised, and few sulfide grains persist. Unoxidised sand tailings contain 10-20 vol.% stibnite (Sb2S3) containing up to 5% As, with subordinate arsenopyrite (FeAsS), and minor pyrite (FeS2). The sand tailings are variably oxidised on a scale of 2-10 cm, but original depositional layering is preserved during oxidation and formation of senarmontite (Sb2O3). Oxidation of sand tailings has resulted in localised mobility of both Sb and As on the cm scale, resulting in redistribution of these metalloids with iron oxyhydroxide around sand grain boundaries. Experiments demonstrate that Sb mobility decreases with time on a scale of days. Attenuation of both As and Sb occurs due to adsorption on to iron oxyhydroxides which are formed during oxidation of the smelter residues. There is no detectable loss of Sb or As from the smelter site into the adjacent river, <50 m away, which has elevated Sb (ca. 20 μg/l) and As (ca. 7 μg /l) from mineralised rocks upstream. Despite the high concentrations of Sb and As in the smelter residues, these metalloids are not being released into the environment. - High levels of antimony in primitive smelter soils remain largely immobile on the metre scale

  2. Aluminium Alloy-Based Metal Matrix Composites: A Potential Material for Wear Resistant Applications

    OpenAIRE

    Rupa Dasgupta

    2012-01-01

    Aluminium alloy-based metal matrix composites (AMMCs) have been by now established themselves as a suitable wear resistant material especially for sliding wear applications. However, in actual practice engineering components usually encounter combination of wear types. An attempt has been made in the present paper to highlight the effect of dispersing SiC in 2014 base alloy adopting the liquid metallurgy route on different wear modes like sliding, abrasion, erosion, and combinations of wear m...

  3. Single-crystal tungsten-based alloys with molybdenum and rhenium

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Single crystals of ternary W-based alloys with 2 % Re and less than 7 % Mo have been grown for the first time at the Baikov Institute of Metallurgy and Materials Science RAS. Plasma arc melting allowed us to effectively purify the single crystals from a number of impurities. According to mass spectrometric analysis for 70 elements, the total content of impurities does not exceed 0. 063%. It was found that, as the Mo content increases, the size of first-kind subgrains decreases and their mutual misorientation increases. In the W-based alloy with 2.3 % Re and 6.7% Mo, no first-kind subgrains are observed,whereas second-kind subgrains are elongated along the growth direction. In this case, their total misorientation is well below that in the other low-alloy single crystals.Single-crystal of binary tungsten-based alloys with rhenium were prepared by electron-beam zone melting (1% Re, mass fraction) and plasma arc melting (2%Re, 10%Re, 25%Re (mass fraction)). It was found that the low-alloyed (1%-2 % Rh (mass fraction)) W-based alloys are characterized by a rather perfect single-crystal structure and misorientations of first- and second-kind subgrains of 20-50' and 10-40', respectively. Sections with the coarse-grained structure are observed in ingots of the alloy with 10%and 25% (mass fraction) Rh; in the alloy with 25% Rh, such structure is observed immediately from the seed.A device for measuring the liquidus and solidus temperatures of refractory metallic alloys has been designed. The liquidus temperatures of ternary single crystals (W-Mo-Re) have been measured.The studied single crystals, owing to their purity and high stability of the structure and properties,are widely used in electronics, electrical engineering, and analytical devices for various purposes.

  4. Tissue distribution of residual antimony in rats treated with multiple doses of meglumine antimoniate

    Directory of Open Access Journals (Sweden)

    Deise Riba Coelho

    2014-07-01

    Full Text Available Meglumine antimoniate (MA and sodium stibogluconate are pentavalent antimony (SbV drugs used since the mid-1940s. Notwithstanding the fact that they are first-choice drugs for the treatment of leishmaniases, there are gaps in our knowledge of their toxicological profile, mode of action and kinetics. Little is known about the distribution of antimony in tissues after SbV administration. In this study, we evaluated the Sb content of tissues from male rats 24 h and three weeks after a 21-day course of treatment with MA (300 mg SbV/kg body wt/d, subcutaneous. Sb concentrations in the blood and organs were determined by inductively coupled plasma-mass spectrometry. In rats, as with in humans, the Sb blood levels after MA dosing can be described by a two-compartment model with a fast (t1/2 = 0.6 h and a slow (t1/2 >> 24 h elimination phase. The spleen was the organ that accumulated the highest amount of Sb, while bone and thyroid ranked second in descending order of tissues according to Sb levels (spleen >> bone, thyroid, kidneys > liver, epididymis, lungs, adrenals > prostate > thymus, pancreas, heart, small intestines > skeletal muscle, testes, stomach > brain. The pathophysiological consequences of Sb accumulation in the thyroid and Sb speciation in the liver, thyroid, spleen and bone warrant further studies.

  5. Survey of BGFA Criteria for the Cu-Based Bulk Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    D. Janovszky

    2011-01-01

    Full Text Available To verify the effect of composition on the bulk glass forming ability (BGFA of Cu-based alloys, properties have been collected from the literature (~100 papers, more than 200 alloys. Surveying the BGFA criteria published so far, it has been found that the atomic mismatch condition of Egami-Waseda is fulfilled for all the Cu-based BGFAs, the value being above 0,3. The Zhang Bangwei criterion could be applied for the binary Cu-based alloys. The Miracle and Senkov criteria do not necessarily apply for Cu based bulk amorphous alloys. The critical thickness versus =/(+ plot of Lu and Liu extrapolates to =0.36, somewhat higher than the 0.33 value found in other BGFA alloys. The Park and Kim parameter correlates rather poorly with the critical thickness for Cu based alloys. The Cheney and Vecchino parameter is a good indicator to find the best glass former if it is possible to calculate the exact liquids projection. In 2009 Xiu-lin and Pan defined a new parameter which correlates a bit better with the critical thickness. Based on this survey it is still very difficult to find one parameter in order to characterize the real GFA without an unrealized mechanism of crystallization.

  6. Effect of alloying on elastic properties of ZrN based transition metal nitride alloys

    KAUST Repository

    Kanoun, Mohammed

    2014-09-01

    We report the effect of composition and metal sublattice substitutional element on the structural, elastic and electronic properties of ternary transition metal nitrides Zr1-xMxN with M=Al, Ti, Hf, V, Nb, W and Mo. The analysis of the elastic constants, bulk modulus, shear modulus, Young\\'s modulus, and Poisson\\'s ratio provides insights regarding the mechanical behavior of Zr1-xMxN. We predict that ternary alloys are more ductile compared to their parent binary compounds. The revealed trend in the mechanical behavior might help for experimentalists on the ability of tuning the mechanical properties during the alloying process by varying the concentration of the transition metal. © 2014 Elsevier B.V.

  7. Shape memory alloy wire-based smart natural rubber bearing

    International Nuclear Information System (INIS)

    In this study, two types of smart elastomeric bearings are presented using shape memory alloy (SMA) wires. Due to the unique characteristics of SMAs, such as the superelastic effect and the recentering capability, the residual deformation in SMA-based natural rubber bearings (SMA-NRBs) is significantly reduced whereas the energy dissipation capacity is increased. Two different configurations of SMA wires incorporated in elastomeric bearings are considered. The effect of several parameters, including the shear strain amplitude, the type of SMA, the aspect ratio of the base isolator, the thickness of SMA wire, and the amount of pre-strain in the wires on the performance of SMA-NRBs is investigated. Rubber bearings are composed of natural rubber layers bonded to steel shims as reinforcement. Results show that ferrous SMA wire, FeNiCuAlTaB, with 13.5% superelastic strain and a very low austenite finish temperature (−62 °C), is the best candidate to be used in SMA-NRBs subjected to high shear strain amplitudes. In terms of the lateral flexibility and wire strain level, the smart rubber bearing with a cross configuration of SMA wires is more efficient. Moreover, the cross configuration can be implemented in high-aspect-ratio elastomeric bearings since the strain induced in the wire does not exceed the superelastic range. When cross SMA wires with 2% pre-strain are used in a smart NRB, the dissipated energy is increased by 74% and the residual deformation is decreased by 15%. (paper)

  8. The metallographic investigation of brazed joints in nickel base alloys using various techniques for the production of contrast

    International Nuclear Information System (INIS)

    Brazing with high melting point nickel base brazing alloys permits distortion-free, high strength joints to be produced in high temperature, high alloy steel and nickel alloys which cannot easily be welded. This method is used for gas turbine parts subject to high thermal stresses and in nuclear engineering. (orig.)

  9. Rational design of Nb-based alloys for hydrogen separation: A first principles study

    Directory of Open Access Journals (Sweden)

    Byungki Ryu

    2013-02-01

    Full Text Available We have investigated the effect of alloying metal elements on hydrogen solubility and mechanical integrity of Nb-based alloys, Nb15M1 (where M = Ca–Zn, Ge, using first principles-based calculations. In general, the chemical interaction between the interstitial H and metal is weakened as the alloying element is changed from an early to a late transition metal, leading to lower H solubility and higher resistance to H embrittlement. This effect becomes more pronounced when a smaller alloying element is used due to stronger elastic interaction between interstitial H and metal atoms. These finding may provide scientific basis for rational design of Nb-based hydrogen separation membranes with tailored H solubility to effectively suppress H embrittlement while maintaining excellent hydrogen permeation rate.

  10. Dry sliding wear characteristics of rheocast Mg–Sn based alloys

    International Nuclear Information System (INIS)

    Highlights: • Studied wear behavior of rheocast Mg–Sn based alloys under ambient temperature. • The volumetric wear was found to be increased with increasing applied load. • Different wear micro-mechanism was observed under electron micro-scope. • Plastic deformation and work hardening took place for all the alloys mainly at the higher loads. - Abstract: Present paper focuses on the dry sliding wear behavior of rheocast Mg–Sn based alloys under ambient temperature. The alloys were studied through pin-on-disc wear experiments under four different loading conditions, namely, 9.8, 19.6, 29.4 and 39.2 N. Present investigations highlight the influence of load on the cumulative wear loss, volumetric wear loss, dry sliding wear rate and co-efficient of friction of the different alloys under study. The volumetric wear was found to be increased with increasing applied load. Different wear micro-mechanisms were observed under electron micro-scope. The wear occurs mainly by ploughing mechanism and by delamination also. During wear, extensive plastic deformation and work hardening took place for all the alloys mainly at the higher loads. Micro-structural analysis has been performed for all the alloys at different loading conditions

  11. Hot Workability of CuZr-Based Shape Memory Alloys for Potential High-Temperature Applications

    Science.gov (United States)

    Biffi, Carlo Alberto; Tuissi, Ausonio

    2014-07-01

    The research on high-temperature shape memory alloys has been growing because of the interest of several potential industrial fields, such as automotive, aerospace, mechanical, and control systems. One suitable candidate is given by the CuZr system, because of its relative low price in comparison with others, like the NiTi-based one. In this context, the goal of this work is the study of hot workability of some CuZr-based shape memory alloys. In particular, this study addresses on the effect of hot rolling process on the metallurgical and calorimetric properties of the CuZr system. The addition of some alloying elements (Cr, Co, Ni, and Ti) is taken into account and their effect is also put in comparison with each other. The alloys were produced by means of an arc melting furnace in inert atmosphere under the shape of cigars. Due to the high reactivity of these alloys at high temperature, the cigars were sealed in a stainless steel can before the processing and two different procedures of hot rolling were tested. The characterization of the rolled alloys is performed using discrete scanning calorimetry in terms of evolution of the martensitic transformation and scanning electron microscopy for the microstructural investigations. Additionally, preliminary tests of laser interaction has been also proposed on the alloy more interesting for potential applications, characterized by high transformation temperatures and its good thermal stability.

  12. Investigation of the isothermal precipitation behaviour of nickel-base alloys using electrochemical phase extraction

    International Nuclear Information System (INIS)

    Electrochemical phase extraction methods have been developed empirically for the selective separation of the precipitates in metallic materials. A detailed description of the process has been undertaken to allow optimization for various nickel-base alloys. For this part of the investigation, 16 model alloys were prepared as test electrodes and the electrolyte composition was varied over a wide range. The results enabled a series of effects to be explained on the basis of electrochemical data. The large number of test parameters limited the scope of the preliminary experiments and the range of model alloys used. In the nickel-base alloys, titanium carbo-nitride and primary M6C precipitates were identified. During isothermal ageing, M23C6 (except in Alloy KSN), Ni3Al (in INCONEL 617), Laves phases (in Hastelloy X and INCONEL 617), M12C (in HASTELLOY X and INCONEL 617) and α-tungsten (in the tungsten-containing alloys) were precipitated. The precipitation behaviour changed in the alloys investigated from intracrystalline to intercrystalline with increasing ageing temperature. The intracrystalline secondary precipitations affect the microhardness, structure and the solid-solution lattice. (orig.)

  13. A facile and fast route to prepare antimony (Sb) nanostructures without additives

    KAUST Repository

    Shah, M.A.

    2011-12-01

    Herein, we report a safe, low cost and reproducible approach for the synthesis of antimony (Sb) nanostructures with most of them having prism like morphology and having well defined faces in the range of ∼70210 nm. The organics free approach is based on a reaction of antimony powder and pure water at ∼210 °C without using any harmful additives and amines. The XRD pattern confirmed the composition and crystallinity of the grown nanostructures. The reported method besides being organics free is economical, fast and free of pollution, which will make it suitable for large scale production. Furthermore, it is well expected that such a technique could be extended to prepare many other important metal and metal oxide nanostructures. The prospects of the process are bright and promising. © 2012 Sharif University of Technology. Production and hosting by Elsevier B.V. All rights reserved.

  14. Antimony/Graphitic Carbon Composite Anode for High-Performance Sodium-Ion Batteries.

    Science.gov (United States)

    Zhao, Xin; Vail, Sean A; Lu, Yuhao; Song, Jie; Pan, Wei; Evans, David R; Lee, Jong-Jan

    2016-06-01

    Although the room-temperature rechargeable sodium-ion battery has emerged as an attractive alternative energy storage solution for large-scale deployment, major challenges toward practical sodium-ion battery technology remain including identification and engineering of anode materials that are both technologically feasible and economical. Herein, an antimony-based anode is developed by incorporating antimony into graphitic carbon matrices using low-cost materials and scalable processes. The composite anode exhibits excellent overall performance in terms of packing density, fast charge/discharge capability and cyclability, which is enabled by the conductive and compact graphitic network. A full cell design featuring this composite anode with a hexacyanometallate cathode achieves superior power output and low polarization, which offers the potential for realizing a high-performance, cost-effective sodium-ion battery. PMID:27172376

  15. Biocompatibility of new Ti-Nb-Ta base alloys.

    Science.gov (United States)

    Hussein, Abdelrahman H; Gepreel, Mohamed A-H; Gouda, Mohamed K; Hefnawy, Ahmad M; Kandil, Sherif H

    2016-04-01

    β-type titanium alloys are promising materials in the field of medical implants. The effect of β-phase stability on the mechanical properties, corrosion resistance and cytotoxicity of a newly designed β-type (Ti77Nb17Ta6) biocompatible alloys are studied. The β-phase stability was controlled by the addition of small quantities of Fe and O. X-ray diffraction and microstructural analysis showed that the addition of O and Fe stabilized the β-phase in the treated solution condition. The strength and hardness have increased with the increase in β-phase stability while ductility and Young's modulus have decreased. The potentio-dynamic polarization tests showed that the corrosion resistance of the new alloys is better than Ti-6Al-4V alloy by at least ten times. Neutral red uptake assay cytotoxicity test showed cell viability of at least 95%. The new alloys are promising candidates for biomedical applications due to their high mechanical properties, corrosion resistance, and reduced cytotoxicity. PMID:26838885

  16. How can we adapt to geological scarcity of antimony? Investigation of antimony's substitutability and of other measures to achieve a sustainable use

    NARCIS (Netherlands)

    Henckens, M.L.C.M.; Driessen, P.P.J.; Worrell, E.

    2016-01-01

    Abstract Antimony is an element that is applied in many useful applications for mankind. However, antimony resources are very scarce, when comparing the current extraction rates with the availability of antimony containing ores. From an inter-temporal sustainability perspective, current generations

  17. Interstitial-phase precipitation in iron-base alloys: a comparative study

    International Nuclear Information System (INIS)

    Recent developments have elucidated the atomistic mechanisms of precipitation of interstitial elements in simple alloy systems. However, in the more technologically important iron base alloys, interstitial phase precipitation is generally not well understood. The present experimental study was therefore designed to test the applicability of these concepts to more complex ferrous alloys. Hence, a comparative study was made of interstitial phase precipitation in ferritic Fe-Si-C and in austenitic phosphorus-containing Fe-Cr-Ni steels. These systems were subjected to a variety of quench-age thermal treatments, and the microstructural development was subsequently characterized by transmission electron microscopy

  18. Application of feal intermetallic phase matrix based alloys in the turbine components of a turbocharger

    OpenAIRE

    J. Cebulski

    2015-01-01

    This paper presents a possible application of the state-of-the-art alloys based on the FeAl intermetallic phases as materials for the manufacture of heat-proof turbine components in an automobile turbocharger. The research was aimed at determining the resistance to corrosion of Fe40Al5CrTiB alloy in a gaseous environment containing 9 % O2 + 0,2 % HCl + 0,08 % SO2 + N2. First the kinetics of corrosion processes for the considered alloy were determined at the temperatures of 900 °C, 1 000 °C an...

  19. Mechanical Responses of Superlight β-Based Mg-Li-Al-Zn Wrought Alloys under Resonance

    Science.gov (United States)

    Song, Jenn-Ming; Lin, Yi-Hua; Su, Chien-Wei; Wang, Jian-Yih

    2009-05-01

    To extend the application of lightweight Mg alloys in the automotive industry, this study suggests a β-based Mg-Li alloy (LAZ1110) with superior vibration fracture resistance by means of material design. In the cold-rolled state, a strengthened β matrix by the additions of Al and Zn, as well as intergranular platelike α precipitates, which are able to stunt the crack growth, contributes to a comparable vibration life with commercial Mg-Al-Zn alloys under a similar strain condition.

  20. Thermo-physical properties and phase transformation behavior of thorium-based alloys and oxides

    International Nuclear Information System (INIS)

    In this presentation, the results of classical molecular dynamics (CMD) simulations of lattice thermal expansion (LTE), elastic constants and thermal conductivity of Urania-Thoria, Thoria-Ceria/Plutonia MOX fuels will be presented along with some experimental results using high temperature X-ray diffraction techniques. At the same time, it is very useful to understand the possible phase transformations in Th bases metallic alloys with a view to identify the metastable phases. This aspect is important from phase stability point of view. All these metallic alloys shows phase separation tendencies and complex compound formation. This presentation also discusses the nature of phase transformations in these alloys involving stable and metastable phases

  1. Investigations of carbon diffusion and carbide formation in nickel-based alloys

    International Nuclear Information System (INIS)

    The present thesis describes the carburization behaviour of nickel based alloys in heavily carburizing environments. The mechanisms of carbon diffusion and carbide precipitation in NiCr alloys with and without ternary additions of iron, cobalt or molybdenum have been investigated. Using the results of carburization experiments, a mathematical model which describes carbon diffusion and carbide formation, was developed. The simulation of the carburization process was carried out by an iterative calculation of the local thermodynamic equilibrium in the alloy. An accurate description of the carbon profiles as a function of time became possible by using a finite-difference calculation. (orig.)

  2. Solute partitioning and site preference in γ/γ′ cobalt-base alloys

    International Nuclear Information System (INIS)

    This paper reports three-dimensional atom probe tomography results from a γ/γ′ based Co–Al–W alloy and two quaternary variants of this alloy highlighting the following salient features: (i) sub-nanometer-scale solute partitioning across the γ/γ′ interface as well as solute pile-up at this interface; (ii) the site preference of quaternary elements in γ′ precipitates, Co3(Al, W); and (iii) formation of multiple generations of γ′ precipitates in one of the alloys.

  3. Atom probe analysis of Sn in Zr-based alloys

    International Nuclear Information System (INIS)

    We have extensively used atom-probe field ion microscopy (APFIM) for microanalyses of a heat-treated Zircaloy-4 and Zr-Sn alloys containing 0.6 or 1.39 wt% Sn and clarified as to whether Sn is fully dissolved or not in the α-Zr matrix. It is found that Sn dissolves in the matrix of both Zircaloy-4 and Zr-0.6 wt% Sn alloy upon annealing at 723 K. For Zr-1.39 wt% Sn alloy, after annealing for more than 200 h, the symptom of phase separation has been found. The distribution of Sn in the matrix is changed from the α-quenched state, and local regions enriched with Sn are formed in the matrix. (orig.)

  4. Local atomic ordering in nickel based Ir and Rh alloys

    International Nuclear Information System (INIS)

    Experimental measurements of the diffuse X-ray scattering are performed on alloys of Ni with Rh and Ir. The atomic short range order (SRO) parameters αsub(i) are calculated from the measured intensity. The existence of SRO is established in the two systems. The values of α1 are observed to have anomalously large negative values for all the samples. The experimental data so obtained is interpreted theoretically by calculating the interaction energies on the basis of electronic theory of ordering. Theoretically calculated values of interaction energies are found to be in agreement with the experimentally determined type of order in these alloys. (author)

  5. Martensitic transformation in Co-based ferromagnetic shape memory alloy

    Czech Academy of Sciences Publication Activity Database

    Kopeček, Jaromír; Yokaichiya, F.; Laufek, F.; Jarošová, Markéta; Jurek, Karel; Drahokoupil, Jan; Sedláková-Ignácová, Silvia; Molnár, Peter; Heczko, Oleg

    2012-01-01

    Roč. 122, č. 3 (2012), s. 475-477. ISSN 0587-4246. [International Symposium on Physics of Materials, ISPMA /12./. Praha, 04.09.2011-08.09.2011] R&D Projects: GA ČR(CZ) GA101/09/0702; GA ČR GAP107/10/0824; GA AV ČR IAA100100920 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z10100521 Keywords : microstructure * shape memory alloy s * neutron diffraction * cobalt alloy s Subject RIV: JG - Metallurgy Impact factor: 0.531, year: 2012

  6. Mechanical strenght and niobium and niobium-base alloys substructures

    International Nuclear Information System (INIS)

    Niobium and some of its alloys have been used in several fields of technological applications such as the aerospace, chemical and nuclear industries. This is due to its excelent mechanical stringth at high temperatures and reasonable ductility at low temperatures. In this work, we review the main features of the relationship mechanical strength - substructure in niobium and its alloys, taking into account the presence of impurities, the influence of initial thermal and thermo - mechanical treatments as well as the irradiation by energetic particles. (Author)

  7. Undercooling and demixing of copper-based alloys

    DEFF Research Database (Denmark)

    Kolbe, M.; Brillo, J.; Egry, I.; Herlach, D.M.; Ratke, L.; Chatain, D.; Tinet, N.; Antion, C.; Battezzati, L.; Curiotto, S.; Johnson, E.; Pryds, Nini

    Since the beginning of materials science research under microgravity conditions immiscible alloys have been an interesting subject. New possibilities to investigate such systems are offered by containerless processing techniques. Of particular interest is the ternary system Cu-Fe-Co, and its...... limiting binaries, Cu-Co and Cu-Fe. They all show a metastable miscibility gap in the regime of the undercooled melt. Within the ESA-MAP project “CoolCop”, different aspects of this alloy have been investigated; results obtained so far are reported here....

  8. Corrosion properties of high silicon iron-based alloys in nitric acid

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effect of copper and rare-earth elements on corrosion behavior of ~iigh silicon iron-based alloys in nitric acid was studied by means of static and loading current corrosion experiments. The anodic polarization curve was also made to discuss the corrosion mechanism. The examination on alloy microstructure and SEM corrosion pattern showed that when silicon content reached 14.5%, the Fe3Si phase appeared and the primary structure of the iron-base alloy was ferrite. When adding 4.57% copper in the iron alloy, its corrosion resistance in static diluted sulfuric acid was improved while its corrosion resistance and electrochemical corrosion properties in the nitric acid were decreased. In contrast, the addition of rare earth elements could improve the corrosion properties in all above conditions including in static diluted sulfuric acid and in nitric acid.

  9. Iron-based alloy and nitridation treatment for PEM fuel cell bipolar plates

    Science.gov (United States)

    Brady, Michael P. [Oak Ridge, TN; Yang, Bing [Oak Ridge, TN; Maziasz, Philip J. [Oak Ridge, TN

    2010-11-09

    A corrosion resistant electrically conductive component that can be used as a bipolar plate in a PEM fuel cell application is composed of an alloy substrate which has 10-30 wt. % Cr, 0.5 to 7 wt. % V, and base metal being Fe, and a continuous surface layer of chromium nitride and vanadium nitride essentially free of base metal. A oxide layer of chromium vanadium oxide can be disposed between the alloy substrate and the continuous surface nitride layer. A method to prepare the corrosion resistant electrically conductive component involves a two-step nitridization sequence by exposing the alloy to a oxygen containing gas at an elevated temperature, and subsequently exposing the alloy to an oxygen free nitrogen containing gas at an elevated temperature to yield a component where a continuous chromium nitride layer free of iron has formed at the surface.

  10. Atomic site location by channelling enhanced microanalysis (ALCHEMI) in γ'-strengthened Ni- and Pt-base alloys

    International Nuclear Information System (INIS)

    The additions of alloying elements to Ni- and Pt-base alloys influence the microstructure and thereby the creep properties, whereas the mechanism is uncertain. Therefore atomic site location by channelling enhanced microanalysis (ALCHEMI) was used to determine the site partitioning of ternary and quaternary alloying elements in the L12-ordered γ'-phase. Two ternary Ni-Al alloys with Cr and Ti additions were investigated. The measured site partitioning showed that Cr and Ti atoms prefer the Al-sublattice sites. For a ternary Pt-Al-Cr alloy, it was found that Cr atoms occupy Al sites. The influence of Ni as a fourth alloying element in a Pt-Al-Cr-Ni alloy on the site partitioning was also investigated. The detected results give evidence that in the quaternary alloy Cr and Ni atoms prefer the Pt sublattice. First principles calculations were used to support the experimental data

  11. Burner Rig Hot Corrosion of Five Ni-Base Alloys Including Mar-M247

    Science.gov (United States)

    Nesbitt, James A.; Helmink, R.; Harris, K.; Erickson, G.

    2000-01-01

    The hot corrosion resistance of four new Ni-base superalloys was compared to that of Mar-M247 by testing in a Mach 0.3 burner rig at 900 C for 300 1-hr cycles. While the Al content was held the same as in the Mar-M247, the Cr and Co levels in the four new alloys were decreased while other strengthening elements (Re, Ta) were increased. Surprisingly, despite their lower Cr and Co contents, the hot corrosion behavior of all four new alloys was superior to that of the Mar-M247 alloy. The Mar-M247 alloy began to lose weight almost immediately whereas the other four alloys appeared to undergo an incubation period of 50-150 1-hr cycles. Examination of the cross-sectional microstructures showed regions of rampant corrosion attack (propagation stage) in all five alloys after 300 1-hr cycles . This rampant corrosion morphology was similar for each of the alloys with Ni and Cr sulfides located in an inner subscale region. The morphology of the attack suggests a classic "Type I", or high temperature, hot corrosion attack.

  12. Atmospheric Corrosion of Different Fe-based Alloys in Nanocrystalline State

    Science.gov (United States)

    Sitek, J.; Sedlačková, K.; Seberíni, M.

    2005-07-01

    Nanocrystalline Fe-based alloys are interesting for their soft magnetic properties. Because these alloys are potentially applicable in outdoor-working components, their corrosion behaviour requires careful analysis. This work presents the results of the atmospheric corrosion tests in industrial and rural environments performed for up to 6 months. We compared the corrosion behaviour of two different compositions of NANOPERM-type alloys: Fe87.5Zr6.5B6 and Fe76Mo8Cu1B15 with classical FINEMET alloys of the nominal composition of Fe73.5Cu1Nb3Si13.5B9 type. The techniques of Mössbauer spectroscopy, conversion electron Mössbauer spectroscopy, X-ray diffraction and transmission electron microscopy have been employed to compare their corrosion rate, characterize corrosion products and inspect the structural changes of the nanocrystalline structure. It was found that the Si-containing FINEMET alloys are the most corrosion-resistant whereas worse corrosion properties were observed for molybdenum-containing Fe76Mo8Cu1B15 alloy. The corrosion product formed on the surface of NANOPERM-type alloys showed a needlelike morphology and a poor crystalline order and has been identified as lepidocrocite, γ-FeOOH.

  13. Microstructural observations of the crystallization of amorphous Fe-Si-B based magnetic alloys

    International Nuclear Information System (INIS)

    The effect of Cu and Nb alloying additions on the crystallization of Fe-Si-B based alloys were studied. DSC, XRD, TEM, EELS and VSM techniques were used to study the thermal properties, phase formation during primary crystallization, morphological transitions and magnetic properties. The additions of individual Cu or Nb alloying additions changed the crystallization temperature as well as the activation energy for primary crystallization. The phases formed during primary crystallization for the Fe77.5Si13.5B9, Fe76.5Si13.5B9Cu1 and Fe74.5Si13.5B9Nb3Cu1 alloys are the same, however the morphologies are significantly different. Alloying additions of 3 at.% Nb induced a change in the crystallization mechanism and the type of phases formed. The combined additions of Cu and Nb resulted in the formation of nanocrystals. B atoms were found to be rejected around dendrites formed during primary crystallization of the Fe77.5Si13.5B9 alloy. The highest saturation magnetization and the lowest coercivity is obtained in the Fe77.5Si13.5B9 and Fe74.5Si13.5B9Nb3Cu1 alloy respectively after annealing at 550 deg. C for 1 h

  14. The Degradation Interface of Magnesium Based Alloys in Direct Contact with Human Primary Osteoblast Cells

    OpenAIRE

    Ahmad Agha, Nezha; Willumeit-Römer, Regine; Laipple, Daniel; Luthringer, Bérengère; Feyerabend, Frank

    2016-01-01

    Magnesium alloys have been identified as a new generation material of orthopaedic implants. In vitro setups mimicking physiological conditions are promising for material / degradation analysis prior to in vivo studies however the direct influence of cell on the degradation mechanism has never been investigated. For the first time, the direct, active, influence of human primary osteoblasts on magnesium-based materials (pure magnesium, Mg-2Ag and Mg-10Gd alloys) is studied for up to 14 days. Se...

  15. Formation Mechanism of Curved Martensite Structures in Cu-based Shape Memory Alloys

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The curved martensite structures have been observed in CuZnAl-based shape memory alloys by both transmission electron microscope and optical microscope. It was found that the curved martensite structures observed in as-solution treated, as-aged and as-trained alloys usually occurred around dislocation tangles or precipitate, at the plate boundary or grain boundary, and when the growing plates collided with each other or alternate mutually.

  16. RESIDUAL STRESS IN NICKEL BASE SUPER ALLOY UDIMET 720 FOR DIFFERENT SURFACE CONDITIONS

    OpenAIRE

    B.R.SRIDHAR,; S.RAMACHANDRA,; U.CHANDRASEKAR

    2011-01-01

    Nickel base super alloy Udimet 720 finds applications in gas turbine engine components like discs, shafts and blades. These components rotate at high speeds in a gas turbine engine and consequently experience both high cycle fatigue (HCF) and low cycle fatigue (LCF) due to dynamic loads and temperatures. Since residual stress affects both HCF and LCF properties, study of residual stress for varying surface conditions for this alloy assumes significance. Specimens extracted from a forging were...

  17. Plasma sprayed ceramic thermal barrier coating for NiAl-based intermetallic alloys

    Science.gov (United States)

    Miller, Robert A. (Inventor); Doychak, Joseph (Inventor)

    1994-01-01

    A thermal barrier coating system consists of two layers of a zirconia-yttria ceramic. The first layer is applied by low pressure plasma spraying. The second layer is applied by conventional atmospheric pressure plasma spraying. This facilitates the attachment of a durable thermally insulating ceramic coating directly to the surface of a highly oxidation resistant NiAl-based intermetallic alloy after the alloy has been preoxidized to promote the formation of a desirable Al2O3 scale.

  18. Formation of silicide based oxidation resistant coating over Mo-30 wt. % W alloy

    International Nuclear Information System (INIS)

    Silicide based oxidation resistant coatings were developed over Mo-30 W alloy using halide activated pack cementation process. Coated samples were characterized by SEM, optical microscopy, EDX and hardness measurements. Isothermal oxidation tests of coated alloy performed at 1000 deg C for 25h revealed a smaller weight gain at the initial stage of oxidation followed by no weight change indicating the protective nature of the coating. (author)

  19. Impact of dilution on the microstructure and properties of Ni-based 625 alloy coatings

    OpenAIRE

    Tiago Jose Antoszczyszyn; Rodrigo Metz Gabriel Paes; Ana Sofia Clímaco Monteiro de Oliveira; Adriano Scheid

    2014-01-01

    Nickel-based alloy IN 625 is used to protect components of aircrafts, power generation and oil refinery due to an association of toughness and high corrosion resistance. These properties are associated with the chemical composition and microstructure of coatings which depend on the processing parameters and the composition of the component being protected. This paper assessed impact of dilution on the microstructure and properties of the Ni alloy IN 625 deposited by Plasma Transferred Arc (PT...

  20. A first principles examination of phase stability in FCC-based Ni-V substitutional alloys

    International Nuclear Information System (INIS)

    In this paper the phase stability of fcc- based Ni-V substitutional alloys is investigated using linear muffin-tin orbitals total energy (LMTO) calculations. The method of Connolly and Williams (CWM) is used to extract many body interactions from the ground state energies of selected ordered configurations. These interactions are used in conjunction with the cluster variations method (CVM) to calculate the alloy phase diagram. The dependence of the interactions on the choice of configurations used to calculate them is examined

  1. Welding of cobalt-based amorphous alloys with Nd: YAG laser

    International Nuclear Information System (INIS)

    The paper describes the results concerning the investigation of the welding of cobalt-based amorphous alloys with Nd:YAG laser. Five alloys with different chemical structure and dimensions in shape of amorphous metal foils were welded. The quality of the welded joints were tested by using a microstructure analysis with an optical microscope and SEM, when the metal graphic structure, the chemical structure and the microhardness of the welded joints were tested as well. (Author)

  2. Control of equiaxed grains in a complicated Cu-Ni based alloy prepared by centrifugal casting

    OpenAIRE

    Luo Zongqiang; Zhang Weiwen; Xin Baoliang

    2011-01-01

    A complicated Cu-Ni based alloy was developed to fabricate wear-resisting bush for high temperature application. The concern focuses on the control of equiaxed grains in the developed alloy ingot prepared by centrifugal casting. The results show that the equiaxed grains are determined by the pouring temperature of the melt, the cooling rate and the rotation speed of the mold. With the decrease in pouring temperature, the fraction of the equiaxed grains in the transverse section of the ingot i...

  3. Undercooling and demixing of copper-based alloys

    DEFF Research Database (Denmark)

    Kolbe, M.; Brillo, J.; Egry, I.; Herlach, D.M.; Ratke, L.; Chatain, D.; Tinet, N.; Antion, C.; Battezzati, L.; Curiotto, S.; Johnson, E.; Pryds, Nini

    Since the beginning of materials science research under microgravity conditions immiscible alloys have been an interesting subject. New possibilities to investigate such systems are offered by containerless processing techniques. Of particular interest is the ternary system Cu-Fe-Co, and its limi...

  4. SYNTHESIS AND PERFORMANCE OF FE-BASED AMORPHOUS ALLOYS FOR NUCLEAR WASTE REPOSITORY APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kaufman, L; Perepezko, J; Hildal, K

    2007-02-08

    In several Fe-based alloy systems it is possible to produce glasses with cooling rates as low as 100 K/s that exhibit outstanding corrosion resistance compared to typical crystalline alloys such as high-performance stainless steels and Ni-based C-22 alloy. Moreover, novel alloy compositions can be synthesized to maximize corrosion resistance (i.e. adding Cr and Mo) and to improve radiation compatibility (adding B) and still maintain glass forming ability. The applicability of Fe-based amorphous coatings in typical environments where corrosion resistance and thermal stability are critical issues has been examined in terms of amorphous phase stability and glass-forming ability through a coordinated computational analysis and experimental validation. Similarly, a novel computational thermodynamics approach has been developed to explore the compositional sensitivity of glass-forming ability and thermal stability. Also, the synthesis and characterization of alloys with increased cross-section for thermal neutron capture will be outlined to demonstrate that through careful design of alloy composition it is possible to tailor the material properties of the thermally spray-formed amorphous coating to accommodate the challenges anticipated in typical nuclear waste storage applications over tens of thousands of years in a variety of corrosive environments.

  5. Thermodynamic calculations in the development of high-temperature Co–Re-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gorr, Bronislava, E-mail: gorr@ifwt.mb.uni-siegen.de [University of Siegen, Institut für Werkstofftechnik, Siegen (Germany); Christ, Hans-Jürgen [University of Siegen, Institut für Werkstofftechnik, Siegen (Germany); Mukherji, Debashis; Rösler, Joachim [TU Braunschweig, Institut für Werkstoffe, Braunschweig (Germany)

    2014-01-05

    Highlights: • Phase diagram as a starting point for alloy development. • Design of pre-oxidation treatments by means of thermodynamic assessment. • Contribution of thermodynamic calculations to the general understanding of materials chemistry. -- Abstract: The experimental Co–Re-based alloys are being developed for high-temperature applications for service temperatures beyond 1100 °C. One of the main tasks of this research is to find the optimal chemical composition. Thermodynamic calculations are very helpful for composition selection and optimization. In this study, thermodynamic calculations were used to identify potential alloying elements and to determine suitable concentration ranges to improve properties, such as strength and oxidation resistance that are essential for high-temperature structural materials. The calculated ternary phase diagram of the Co–Re–Cr system was used to design the reference model alloy. Corrosion products formed under different atmospheric conditions were reliably predicted for a number of model Co–Re-based alloys. Pre-oxidation treatment, a common method used to improve the oxidation resistance of alloys in aggressive atmosphere, was successfully designed based on thermodynamic considerations.

  6. Improvement of Zr-base alloy for nuclear reactor core materials application by Mo addition

    International Nuclear Information System (INIS)

    The role of Mo in Zr-based alloys was studied in terms of the microstructure, texture and corrosion resistance. The base compositions of the experimental alloys were Zr-1Nb and Zr-1Nb-1Sn-0.1Fe to which Mo was added in varying amount up to 0.5%. Buttons of 300 g in weight have been produced by plasma arc remelting (PAR) and processed in sequence by hot forging, hot rolling, beta annealing, cold rolling and recrystallization annealing. It was confirmed that Mo addition resulted in grain refinement: beta grains as well as recrystallized alpha grains. This, in turn reduced the formation frequency and the size of twins and relaxed of the surface normal preferred orientation, fn. In the corrosion test in water containing 220 ppm LiOH (360 deg C, 17.9 MPa), the alloys with up to 0.2% Mo showed a good corrosion resistance whereas that with 0.5% Mo showed a degraded resistance. Apparently, the corrosion resistance was related to the density and morphology of the second phase particles. Alloys containing fine and uniformly distributed β-Nb particles showed good corrosion resistance whereas those containing excessive number or undesirable distribution of particles particularly in uncrystallized region showed degraded corrosion resistance. Overall, the present study suggests that alloying of up to 0.2% Mo should be favorably considered for improving the mechanical properties without impairing the corrosion resistance of Zr-based alloys for nuclear core applications. (author)

  7. Nickel-base alloy forgings for advanced high temperature power plants

    Energy Technology Data Exchange (ETDEWEB)

    Donth, B.; Diwo, A.; Blaes, N.; Bokelmann, D. [Saarschmiede GmbH Freiformschmiede, Voelklingen (Germany)

    2008-07-01

    The strong efforts to reduce the CO{sub 2} emissions lead to the demand for improved thermal efficiency of coal fired power plants. An increased thermal efficiency can be realised by higher steam temperatures and pressures in the boiler and the turbine. The European development aims for steam temperatures of 700 C which requires the development and use of new materials and also associated process technology for large components. Temperatures of 700 C and above are too high for the application of ferritic steels and therefore only Nickel-Base Alloys can fulfill the required material properties. In particular the Nickel-Base Alloy A617 is the most candidate alloy on which was focused the investigation and development in several German and European programs during the last 10 years. The goal is to verify and improve the attainable material properties and ultrasonic detectability of large Alloy 617 forgings for turbine rotors and boiler parts. For many years Saarschmiede has been manufacturing nickel and cobalt alloys and is participating the research programs by developing the manufacturing routes for large turbine rotor forgings up to a maximum diameter of 1000 mm as well as for forged tubes and valve parts for the boiler side. The experiences in manufacturing and testing of very large forgings made from nickel base alloys for 700 C steam power plants are reported. (orig.)

  8. Sheet texture modification in magnesium-based alloys by selective rare earth alloying

    International Nuclear Information System (INIS)

    Research highlights: → Different RE elements gave distinct microstructures and imparted different properties. → Gd demonstrated the highest potential to modify the sheet texture of rolled Mg. → Gd yielded excellent mechanical properties despite a coarse-grained microstructure. → RE alloying seems to promote the hard deformation mechanisms in Mg. → Indications of PSN were found in the annealed microstructures of rolled sheets. - Abstract: The current study examines the influence of select rare earth elements; Gd, Nd, Ce, La and mischmetal (MM) on the sheet texture modification during warm rolling and annealing of a ZEK100 magnesium alloy, and the resulting formability and anisotropy during subsequent tensile testing at room temperature. It was found that all the investigated RE elements led to weak sheet textures and hence promoted enhanced ductility and reduced anisotropy over conventional Mg sheet. Gd was of a particular interest because it gave rise to a desired Mg sheet texture despite its coarsest grain size resulting in promising mechanical properties. It is suggested that solute related effects on the grain boundary migration and the relative strengths of different deformation mechanisms are responsible for altering the common concepts of recrystallization and grain growth during annealing, and the activation scenarios of slip and twinning during deformation.

  9. Bond strength of resin cements to noble and base metal alloys with different surface treatments.

    Directory of Open Access Journals (Sweden)

    Farkhondeh Raeisosadat

    2014-10-01

    Full Text Available The bond strength of resin cements to metal alloys depends on the type of the metal, conditioning methods and the adhesive resins used. The purpose of this study was to evaluate the bond strength of resin cements to base and noble metal alloys after sand blasting or application of silano-pen.Cylinders of light cured Z 250 composite were cemented to "Degubond 4" (Au Pd and "Verabond" (Ni Cr alloys by either RelyX Unicem or Panavia F2, after sandblasting or treating the alloys with Silano-Pen. The shear bond strengths were evaluated. Data were analyzed by three-way ANOVA and t tests at a significance level of P<0.05.When the alloys were treated by Silano-Pen, RelyX Unicem showed a higher bond strength for Degubond 4 (P=0.021 and Verabond (P< 0.001. No significant difference was observed in the bond strength of Panavia F2 to the alloys after either of surface treatments, Degubond 4 (P=0.291 and Verabond (P=0.899. Panavia F2 showed a higher bond strength to sandblasted Verabond compared to RelyX Unicem (P=0.003. The bond strength of RelyX Unicem was significantly higher to Silano-Pen treated Verabond (P=0.011. The bond strength of the cements to sandblasted Degubond 4 showed no significant difference (P=0.59. RelyX Unicem had a higher bond strength to Silano-Pen treated Degubond 4 (P=0.035.The bond strength of resin cements to Verabond alloy was significantly higher than Degubond 4. RelyX Unicem had a higher bond strength to Silano-Pen treated alloys. Surface treatments of the alloys did not affect the bond strength of Panavia F2.

  10. Properties of thermally stable PM Al-Cr based alloy

    Energy Technology Data Exchange (ETDEWEB)

    Vojtech, D. [Department of Metals and Corrosion Engineering, Institute of Chemical Technology, Prague, Technicka 5, 166 28 Prague 6 (Czech Republic)], E-mail: Dalibor.Vojtech@vscht.cz; Verner, J. [Department of Metals and Corrosion Engineering, Institute of Chemical Technology, Prague, Technicka 5, 166 28 Prague 6 (Czech Republic); Serak, J. [Department of Metals and Corrosion Engineering, Institute of Chemical Technology, Prague, Technicka 5, 166 28 Prague 6 (Czech Republic); Simancik, F. [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 831 02 Bratislava 3 (Slovakia); Balog, M. [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 831 02 Bratislava 3 (Slovakia); Nagy, J. [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 831 02 Bratislava 3 (Slovakia)

    2007-06-15

    The presented paper describes properties of Al-6.0 wt.%Cr-2.3 wt.%Fe-0.4 wt.%Ti-0.7 wt.%Si alloy produced by powder metallurgy (PM). The powder alloy was prepared by the pressure nitrogen melt atomization. The granulometric powder fraction of less than 45 {mu}m was then hot-extruded at 450 deg. C to produce a rod of 6 mm in diameter. Microstructure of the as-extruded material was composed of recrystallized {alpha}(Al) grains (the average grain size of 640 nm) and Al{sub 13}Cr{sub 2} spheroids (the average particle diameter of 130 nm and interparticle spacing of 290 nm). Metastable phases were not observed due to their decomposition on the hot extrusion. Hardness of the as-extruded material was 108 HV1, ultimate tensile strength, 327 MPa, yield strength, 258 MPa and elongation, 14%. Mechanical properties resulted mainly from Hall-Petch strengthening. The room-temperature mechanical properties were also measured after a long-term annealing at 400 deg. C. The investigated PM material was compared with the commercial Al-11.8 wt.%Si-0.9 wt.%Ni-1.2 wt.%Cu-1.2 wt.%Mg casting alloy generally applied at elevated temperatures. The PM alloy showed much higher thermal stability, since its room temperature hardness and tensile properties did not degradate significantly even after annealing at 400 deg. C/200 h. In contrast, the hardness and strength of the casting alloy reduced rapidly already after a 30 min annealing. The excellent thermal stability of the investigated PM material was a consequence of very slow diffusivities and low equilibrium solubilities of chromium and iron in solid aluminium.

  11. Properties of thermally stable PM Al-Cr based alloy

    International Nuclear Information System (INIS)

    The presented paper describes properties of Al-6.0 wt.%Cr-2.3 wt.%Fe-0.4 wt.%Ti-0.7 wt.%Si alloy produced by powder metallurgy (PM). The powder alloy was prepared by the pressure nitrogen melt atomization. The granulometric powder fraction of less than 45 μm was then hot-extruded at 450 deg. C to produce a rod of 6 mm in diameter. Microstructure of the as-extruded material was composed of recrystallized α(Al) grains (the average grain size of 640 nm) and Al13Cr2 spheroids (the average particle diameter of 130 nm and interparticle spacing of 290 nm). Metastable phases were not observed due to their decomposition on the hot extrusion. Hardness of the as-extruded material was 108 HV1, ultimate tensile strength, 327 MPa, yield strength, 258 MPa and elongation, 14%. Mechanical properties resulted mainly from Hall-Petch strengthening. The room-temperature mechanical properties were also measured after a long-term annealing at 400 deg. C. The investigated PM material was compared with the commercial Al-11.8 wt.%Si-0.9 wt.%Ni-1.2 wt.%Cu-1.2 wt.%Mg casting alloy generally applied at elevated temperatures. The PM alloy showed much higher thermal stability, since its room temperature hardness and tensile properties did not degradate significantly even after annealing at 400 deg. C/200 h. In contrast, the hardness and strength of the casting alloy reduced rapidly already after a 30 min annealing. The excellent thermal stability of the investigated PM material was a consequence of very slow diffusivities and low equilibrium solubilities of chromium and iron in solid aluminium

  12. Microstructure and elemental composition of electrochemically formed dendrites on lead-free micro-alloyed low Ag solder alloys used in electronics

    International Nuclear Information System (INIS)

    Highlights: • The electrochemical migration is investigated on micro-alloyed low Ag solders. • Transmission electron microscopy is applied to investigate dendrites. • Antimony (micro-alloy) takes part during electrochemical migration processes. • The electrochemical migration model of antimony is established. - Abstract: The Electrochemical Migration (ECM) behaviour of lead-free, micro-alloyed, low Ag solder alloys was investigated using Scanning Transmission Electron Microscopy (STEM), Energy Disperse X-ray Spectroscopy (EDS) and electron diffraction methods. Different solder alloys were investigated by Water Drop (WD) tests to stimulate ECM failure mechanism. After WD tests, differently structured dendrites were formed depending on the solder alloy types. The results showed that micro-alloying components (e.g. Sb) also played role during the ECM processes. The novelty of this study is the demonstration that Sb can take part in the ECM process; the ECM model of Sb is also discussed

  13. Basic research for alloy design of Nb-base alloys as ultra high temperature structural materials; Chokoon kozoyo niobuki gokin no gokin sekkei no tame no kisoteki kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Miura, E. [Tohoku University, Sendai (Japan); Yoshimi, K.; Hanada, S. [Tohoku Univ., Sendai (Japan). Research Inst. for Iron, Steel and Other Metals

    1997-02-01

    This paper describes an influence of additional elements on the high temperature deformation behavior of Nb-base solid solution alloys. Highly concentrated solid solution single crystals of Nb-Ta and Nb-Mo alloys were prepared. Compression test and strain rate sudden change test were conducted in the vacuum at temperatures ranging from 77 to 1773 K, to determine the strain rate sensitivity index. Yield stress of the Nb-Ta alloy was similar to that of Nb alloy at temperatures over 0.3{times}T{sub M}, where T{sub M} is fusing point of Nb. While, the yield stress increased with increasing the impurity oxygen concentration at temperatures below 0.3{times}T{sub M}. The yield stress became much higher than that of Nb alloy. The strain rate sensitivity index showed positive values in the whole temperature range. On the other hand, the yield stress of Nb-Mo alloy was higher than that of Nb alloy in the whole temperature range, and increased with increasing the Mo concentration. The strain rate sensitivity index showed negative values at the temperature range from 0.3{times}T{sub M} to 0.4{times}T{sub M}. It was found that serration occurred often for Nb-40Mo alloys. 1 ref., 4 figs., 1 tab.

  14. Accumulation of antimony and other potentially toxic elements in plants around a former antimony mine located in the Ribes Valley (Eastern Pyrenees)

    Science.gov (United States)

    Bech, Jaume; Corrales, Isabel; Duran, Paola; Roca, Núria; Tume, Pedro; Barceló, Juan; Poschenrieder, Charlotte

    2010-05-01

    Soil contamination by antimony is of increasing environmental concern due to the use of this amphoterous p-block element in many industrial applications such as flame retardant, electronics, alloys, rubber and textile industries. However, little is still known about the response of plants to antimony. Here we report on the accumulation of antimony and other potentially toxic elements (mainly As, Pb and Cu) in plants growing around a former antimony mine in the ribes Valley located in the Eastern Pyrenees (424078E, 4686100N alt. 1145 m.a.s.l) that was operating approximately between the years 1870 to 1960. The ore mineral veins are included in quartz gangue. The main ores were: Sulphides: Stibnite (Sb2S3), Pyrite (FeS2), Sphalerite (ZnS), Arsenopyrite (FeAs), Galenite (PbS), Chalcopyrite (CuFeS2), Tetrahydrite (Cu5Sb2S3). Sulphosals: Boulangerite (5PbS•2Sb2S3), Jamesonite (4PbS•FeS•3Sb2S3), Zinckenite (6PbS•7Sb2S3), Plagionite (5PbS•4Sb2S3), Bournonite PbCu (Sb,As)S3, Pyrargirite (Ag3SbS3). Soil and plant samples were taken at five locations with different levels of Sb, As, and polymetallic contamination. Both pseudototal (aqua regia soluble) and extractable (EDTA) concentrations of metals from sites with low (sites 1 and 2), moderate (site 3 and 4) and high (sites 5 and 6) pollutant burdens were studied. The range of agua regia and EDTA values in mgkg-1 is as follows: Sb 8-2904 and 0.88-44; As: 33-16186 and 3.2-167; Pb: 79-4794 and 49-397; Cu: 66-712 and 48-56 mg•kg-1, respectively). While sites 1 to 4 had alkaline soil pH (7.4-8.7), sites 5 and 6 were acidic with values of 6 and 4.6, respectively. Different herbaceous plant species (Poa annua, Echium vulgare, Sonchus asper, Barbera verna among others) at the low and moderately polluted sites were able to efficiently restrict Sb and As transport to shoots showing average concentration ranges between 5.5 and 23 mg/kg As and 1.21 mg/kg and 4.9 mg/kg Sb. However, at the highly polluted acidic sites (5 and

  15. Fracture mechanics data and modeling of environmental cracking of nickel-base alloys in high temperature water

    International Nuclear Information System (INIS)

    This paper reports on environmental cracking of ductile nickel-base alloys which has occurred both in pressurized water reactors and boiling water reactor components such as pressure-vessel safe ends, weld butters, and filler metals for joining nickel-base alloys or dissimilar metals, and attachment welding pads on pressure vessels. Accurate assessment of the interrelated effects of material, environment, and mechanics on environmental cracking behavior of ductile nickel-base alloys in 288C water

  16. Improvement on Hot Workability of γ-TiAl Base Alloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    γ-TiAl base alloys have potential usage in aerospace engine fortheir high specific strength. In order to improve their poor hot workability, a new approach of hot deformation processing was investigated. The starting microstructure of Ti-46.5Al-2.5V-1.0Cr (atom percent, %) alloy is fully lamellar (FL) microstructure. The near gamma (NG) microstructure can be obtained through Nickel microalloying and heat treatment at 1 150 ℃. The isothermal compression tests were conducted on both materials using MTS machine at temperatures of 950 ℃, 1 000 ℃, and 1 050 ℃, and the strain rates of 0.01, 0.1 and 1 s-1. Compared with the γ-TiAl alloy with FL microstructure, the Ni-bearing alloy with NG microstructure has better hot workability, such as enlarged hot workable region, decreased flow stresses, more uniform and finer deformed microstructure.

  17. Effect of Sr on forming properties of Al-Mg-Si based alloy sheets

    Institute of Scientific and Technical Information of China (English)

    LU Guang-xi; CHEN Hai-jun; GUAN Shao-kang

    2006-01-01

    The effects of Sr element on the forming properties of the Al-Mg-Si based alloy sheets were studied by tensile test,metallograph, DSC, XRD, SEM and TEM. The results show that the tensile strength of aluminum alloy sheet added 0.033%(mass fraction)Sr increases comparing with that of free Sr. Simultaneously, the forming properties of sheets evidently increase, the elongation hardenability (n) and plastic strain ratio (r) and Erichsen number increase 27.8%, 11.1%, 10.8% and 12%, respectively,and the forming limit diagram increases evidently, too. The analysis shows that Sr is surface active element, which can refine grains of alloys, promote precipitation, reduce activation energy ofβ" phase, and lead the formation of α-(Al8Fe2Si) phase instead of β-(Al5FeSi) phase. As a result, the forming properties of the alloy sheet increase.

  18. Microstructure evolution model based on deformation mechanism of titanium alloy in hot forming

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-li; LI Miao-quan

    2005-01-01

    The microstructure evolution in hot forming will affect the mechanical properties of the formed product.However, the microstructure is sensitive to the process variables in deformation process of metals and alloys. A microstructure evolution model of a titanium alloy in hot forming, which included dislocation density rate and primary α phase grain size, was presented according to the deformation mechanism and driving forces, in which the effect of the dislocation density rate on the grain growth was studied firstly. Applying the model to the high temperature deformation process of a TC6 alloy with deformation temperature of 1 133 - 1 223 K, strain rate of 0.01 -50 s-1 and height reduction of 30%, 40% and 50%, the material constants in the present model were calculated by the genetic algorithm(GA) based objective optimization techniques. The calculated results of a TC6 alloy are in good agreement with the experimental ones.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-08-10

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

  20. Thermal analysis of selected tin-based lead-free solder alloys

    DEFF Research Database (Denmark)

    Palcut, Marián; Sopoušek, J.; Trnková, L.; Hodúlová, E.; Szewczyková, B.; Ožvold, M.; Turňa, M.; Janovec, J.

    2009-01-01

    The Sn-Ag-Cu alloys have favourable solderability and wetting properties and are, therefore, being considered as potential lead-free solder materials. In the present study, tin-based Sn-Ag-Cu and Sn-Ag-Cu-Bi alloys were studied in detail by a differential scanning calorimetry (DSC) and...... thermodynamic calculations using the CALPHAD approach. The amount of the alloying elements in the materials was chosen to be close to the respective eutectic composition and the nominal compositions were the following: Sn-3.7Ag-0.7Cu, Sn-1.0Ag-0.5Cu-1Bi (in wt.%). Thermal effects during melting and solidifying...... simulated using the Thermo-Calc software package. This approach enabled us to obtain the enthalpy of cooling for each alloy and to compare its temperature derivative with the experimental DSC curves....

  1. Cobalt-based orthopaedic alloys: Relationship between forming route, microstructure and tribological performance

    International Nuclear Information System (INIS)

    The average longevity of hip replacement devices is approximately 10–15 years, which generally depends on many factors. But for younger generation patients this would mean that revisions may be required at some stage in order to maintain functional activity. Therefore, research is required to increase the longevity to around 25–30 years; a target that was initially set by John Charnley. The main issues related to metal-on-metal (MoM) hip replacement devices are the high wear rates when malpositioned and the release of metallic ions into the blood stream and surrounding tissues. Work is required to reduce the wear rates and limit the amount of metallic ions being leached out of the current MoM materials, to be able to produce an ideal hip replacement material. The most commonly used MoM material is the cobalt-based alloys, more specifically ASTM F75, due to their excellent wear and corrosion resistance. They are either fabricated using the cast or wrought method, however powder processing of these alloys has been shown to improve the properties. One powder processing technique used is spark plasma sintering, which utilises electric current Joule heating to produce high heating rates to sinter powders to form an alloy. Two conventionally manufactured alloys (ASTM F75 and ASTM F1537) and a spark plasma sintered (SPS) alloy were evaluated for their microstructure, hardness, tribological performance and the release of metallic content. The SPS alloy with oxides and not carbides in its microstructure had the higher hardness, which resulted in the lowest wear and friction coefficient, with lower amounts of chromium and molybdenum detected from the wear debris compared to the ASTM F75 and ASTM F1537. In addition the wear debris size and size distribution of the SPS alloy generated were considerably small, indicating a material that exhibits excellent performance and more favourable compared to the current conventional cobalt based alloys used in orthopaedics

  2. Cobalt-based orthopaedic alloys: Relationship between forming route, microstructure and tribological performance

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Bhairav [Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE (United Kingdom); Favaro, Gregory [CSM Instruments SA, Rue de la Gare 4, Galileo Center, CH-2034 Peseux (Switzerland); Inam, Fawad [Advanced Composite Training and Development Centre and School of Mechanical and Aeronautical Engineering, Glyndwr University, Mold Road, Wrexham LL11 2AW (United Kingdom); School of Engineering and Materials Science and Nanoforce Technology Ltd, Queen Mary University of London, London E1 4NS (United Kingdom); Reece, Michael J. [School of Engineering and Materials Science and Nanoforce Technology Ltd, Queen Mary University of London, London E1 4NS (United Kingdom); Angadji, Arash [Orthopaedic Research UK, Furlong House, 10a Chandos Street, London W1G 9DQ (United Kingdom); Bonfield, William [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Huang, Jie [Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE (United Kingdom); Edirisinghe, Mohan, E-mail: m.edirisinghe@ucl.ac.uk [Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE (United Kingdom)

    2012-07-01

    The average longevity of hip replacement devices is approximately 10-15 years, which generally depends on many factors. But for younger generation patients this would mean that revisions may be required at some stage in order to maintain functional activity. Therefore, research is required to increase the longevity to around 25-30 years; a target that was initially set by John Charnley. The main issues related to metal-on-metal (MoM) hip replacement devices are the high wear rates when malpositioned and the release of metallic ions into the blood stream and surrounding tissues. Work is required to reduce the wear rates and limit the amount of metallic ions being leached out of the current MoM materials, to be able to produce an ideal hip replacement material. The most commonly used MoM material is the cobalt-based alloys, more specifically ASTM F75, due to their excellent wear and corrosion resistance. They are either fabricated using the cast or wrought method, however powder processing of these alloys has been shown to improve the properties. One powder processing technique used is spark plasma sintering, which utilises electric current Joule heating to produce high heating rates to sinter powders to form an alloy. Two conventionally manufactured alloys (ASTM F75 and ASTM F1537) and a spark plasma sintered (SPS) alloy were evaluated for their microstructure, hardness, tribological performance and the release of metallic content. The SPS alloy with oxides and not carbides in its microstructure had the higher hardness, which resulted in the lowest wear and friction coefficient, with lower amounts of chromium and molybdenum detected from the wear debris compared to the ASTM F75 and ASTM F1537. In addition the wear debris size and size distribution of the SPS alloy generated were considerably small, indicating a material that exhibits excellent performance and more favourable compared to the current conventional cobalt based alloys used in orthopaedics. - Highlights

  3. Potentiality of the “Gum Metal” titanium-based alloy for biomedical applications

    International Nuclear Information System (INIS)

    In this study, the “Gum Metal” titanium-based alloy (Ti–23Nb–0.7Ta–2Zr–1.2O) was synthesized by melting and then characterized in order to evaluate its potential for biomedical applications. Thus, the mechanical properties, the corrosion resistance in simulated body fluid and the in vitro cell response were investigated. It was shown that this alloy presents a very high strength, a low Young's modulus and a high recoverable strain by comparison with the titanium alloys currently used in medicine. On the other hand, all electrochemical and corrosion parameters exhibited more favorable values showing a nobler behavior and negligible toxicity in comparison with the commercially pure Ti taken as reference. Furthermore, the biocompatibility tests showed that this alloy induced an excellent response of MC3T3-E1 pre-osteoblasts in terms of attachment, spreading, viability, proliferation and differentiation. Consequently, the “Gum Metal” titanium-based alloy processes useful characteristics for the manufacturing of highly biocompatible medical devices. - Highlights: • The Gum Metal alloy composition was synthesized by melting in this study. • Appropriate mechanical properties for biomedical applications were obtained. • High corrosion resistance in simulated body fluids was observed. • Excellent in-vitro cell response was evidenced

  4. Potentiality of the “Gum Metal” titanium-based alloy for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Gordin, D.M. [Institut des Sciences Chimiques de Rennes (UMR CNRS 6226), INSA Rennes, 20 Avenue des Buttes de Coësmes, F-35043 Rennes Cedex (France); Ion, R. [University of Bucharest, Department of Biochemistry and Molecular Biology, 91-95 Spl. Independentei, 050095 Bucharest (Romania); Vasilescu, C.; Drob, S.I. [Institute of Physical Chemistry “Ilie Murgulescu” of Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Cimpean, A. [University of Bucharest, Department of Biochemistry and Molecular Biology, 91-95 Spl. Independentei, 050095 Bucharest (Romania); Gloriant, T., E-mail: Thierry.Gloriant@insa-rennes.fr [Institut des Sciences Chimiques de Rennes (UMR CNRS 6226), INSA Rennes, 20 Avenue des Buttes de Coësmes, F-35043 Rennes Cedex (France)

    2014-11-01

    In this study, the “Gum Metal” titanium-based alloy (Ti–23Nb–0.7Ta–2Zr–1.2O) was synthesized by melting and then characterized in order to evaluate its potential for biomedical applications. Thus, the mechanical properties, the corrosion resistance in simulated body fluid and the in vitro cell response were investigated. It was shown that this alloy presents a very high strength, a low Young's modulus and a high recoverable strain by comparison with the titanium alloys currently used in medicine. On the other hand, all electrochemical and corrosion parameters exhibited more favorable values showing a nobler behavior and negligible toxicity in comparison with the commercially pure Ti taken as reference. Furthermore, the biocompatibility tests showed that this alloy induced an excellent response of MC3T3-E1 pre-osteoblasts in terms of attachment, spreading, viability, proliferation and differentiation. Consequently, the “Gum Metal” titanium-based alloy processes useful characteristics for the manufacturing of highly biocompatible medical devices. - Highlights: • The Gum Metal alloy composition was synthesized by melting in this study. • Appropriate mechanical properties for biomedical applications were obtained. • High corrosion resistance in simulated body fluids was observed. • Excellent in-vitro cell response was evidenced.

  5. Straining electrode behavior and corrosion resistance of nickel base alloys in high temperature acidic solution

    International Nuclear Information System (INIS)

    Repassivation behavior and IGA resistance of nickel base alloys containing 0∼30 wt% chromium was investigated in high temperature acid sulfate solution. (1) The repassivation rate was increased with increasing chromium content. And so the amounts of charge caused by the metal dissolution were decreased with increasing chromium content. (2) Mill-annealed Alloy 600 suffered IGA at low pH environment below about 3.5 at the fixed potentials above the corrosion potential in 10%Na2SO4+H2SO4 solution at 598K. On the other hand, thermally-treated Alloy 690 was hard to occur IGA at low pH environments which mill-annealed Alloy 600 occurred IGA. (3) It was considered that the reason, why nickel base alloys containing high chromium content such as Alloy 690 (60%Ni-30%Cr-10%Fe) had high IGA/SCC resistance in high temperature acidic solution containing sulfate ion, is due to both the promotion of the repassivation and the suppression of the film dissolution by the formation of the dense chromium oxide film

  6. Control of equiaxed grains in a complicated Cu-Ni based alloy prepared by centrifugal casting

    Directory of Open Access Journals (Sweden)

    Luo Zongqiang

    2011-02-01

    Full Text Available A complicated Cu-Ni based alloy was developed to fabricate wear-resisting bush for high temperature application. The concern focuses on the control of equiaxed grains in the developed alloy ingot prepared by centrifugal casting. The results show that the equiaxed grains are determined by the pouring temperature of the melt, the cooling rate and the rotation speed of the mold. With the decrease in pouring temperature, the fraction of the equiaxed grains in the transverse section of the ingot increases and the average length of columnar grain decreases. When the pouring temperature is confined below 1,250℃, complete equiaxed grains can be obtained. Based on the optimal centrifugal casting processing, the tensile strength of the developed alloy ingot with complete equiaxed grains reaches to 810 MPa and 435 MPa at room temperature and 500℃, respectively, which is 14% and 110% higher than that of common commercial QAl10-4-4 alloy. The wear rate of the developed alloy is 7.0 × 10-8 and 3.8 × 10-7 mm3•N-1•mm-1 at room temperature and 500℃, respectively, which is 5 times and 39 times lower than that of QAl10-4-4 alloy.

  7. Pack cementation diffusion coatings for Fe-base and refractory alloys. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, R.A. [Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering

    1998-03-10

    With the aid of computer-assisted calculations of the equilibrium vapor pressures in halide-activated cementation packs, processing conditions have been identified and experimentally verified for the codeposition of two or more alloying elements in a diffusion coating on a variety of steels and refractory metal alloys. A new comprehensive theory to treat the multi-component thermodynamic equilibria in the gas phase for several coexisting solid phases was developed and used. Many different processes to deposit various types of coatings on several types of steels were developed: Cr-Si codeposition for low- or medium-carbon steels, Cr-Al codeposition on low-carbon steels to yield either a Kanthal-type composition (Fe-25Cr-4Al in wt.%) or else a (Fe, Cr){sub 3}Al surface composition. An Fe{sub 3}Al substrate was aluminized to achieve an FeAl surface composition, and boron was also added to ductilize the coating. The developmental Cr-lean ORNL alloys with exceptional creep resistance were Cr-Al coated to achieve excellent oxidation resistance. Alloy wires of Ni-base were aluminized to provide an average composition of Ni{sub 3}Al for use as welding rods. Several different refractory metal alloys based on Cr-Cr{sub 2}Nb have been silicided, also with germanium additions, to provide excellent oxidation resistance. A couple of developmental Cr-Zr alloys were similarly coated and tested.

  8. Description of the capacity degradation mechanism in LaNi{sub 5}-based alloy electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Spodaryk, Mariana, E-mail: poshtamary@ukr.net [Institute for Problems of Materials Science, NAS of Ukraine, 3, Krzhyzhanovsky Str., 03680 Kyiv-142 (Ukraine); Shcherbakova, Larisa; Sameljuk, Anatoly [Institute for Problems of Materials Science, NAS of Ukraine, 3, Krzhyzhanovsky Str., 03680 Kyiv-142 (Ukraine); Wichser, Adrian; Zakaznova-Herzog, Valentina; Holzer, Marco; Braem, Beat [EMPA Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Khyzhun, Oleg [Institute for Problems of Materials Science, NAS of Ukraine, 3, Krzhyzhanovsky Str., 03680 Kyiv-142 (Ukraine); Mauron, Philippe; Remhof, Arndt [EMPA Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Solonin, Yurii [Institute for Problems of Materials Science, NAS of Ukraine, 3, Krzhyzhanovsky Str., 03680 Kyiv-142 (Ukraine); Züttel, Andreas [EMPA Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Ecole polytechnique fédérale de Lausanne (EPFL), Institut des sciences et ingénierie chimiques, CH-1015 Lausanne (Switzerland)

    2015-02-05

    Highlights: • Morphology of gas atomised powders depends on the alloy composition. • Co substituted alloy electrodes exhibit slow activation and slow degradation. • The corrosion mechanism depends on the alloy composition and solubility of metals. - Abstract: The mechanism of the capacity degradation of LaNi{sub 5}-based alloy electrodes was investigated with a special focus on the influence of the alloy and surface composition, as well as the unique structure obtained by gas atomisation. The electrochemical properties, especially the cycle life curve (i.e. the capacity as a function of the cycle number of LaNi{sub 4.5}Al{sub 0.5}, LaNi{sub 2.5}Co{sub 2.4}Al{sub 0.1}, (La + Mm)Ni{sub 3.5}Co{sub 0.7}Al{sub 0.35}Mn{sub 0.4}Zr{sub 0.05}, and MmNi{sub 4.3}Al{sub 0.2}Mn{sub 0.5} alloy electrodes), was analysed and modelled. The capacity degradation upon cycling is determined by the chemical state of the alloy elements and the solubility of their oxides. The cycle life curves for the alloy electrodes without Co exhibited a rapid activation (3–4 cycles to reach maximum capacity), as well as rapid degradation (130–180 cycles for 50% maximum discharge capacity). LaNi{sub 2.5}Co{sub 2.4}Al{sub 0.1} and (La + Mm)Ni{sub 3.5}Co{sub 0.7}Al{sub 0.35}Mn{sub 0.4}Zr{sub 0.05} alloy electrodes activated after 7–10 cycles and showed very stable discharge behaviour (more than 400 cycles). The Co-containing alloy electrodes primarily lose the cycle stability because of mechanical decrepitation, whereas the alloys without Co suffer from selective dissolution of the unstable elements in the potential window, which was shown by our model of alloy degradation and confirmed by means of SEM, WDX, and ICP-OES data.

  9. Antimony distribution and environmental mobility at an historic antimony smelter site, New Zealand.

    Science.gov (United States)

    Wilson, N J; Craw, D; Hunter, K

    2004-05-01

    A historic antimony smelter site at Endeavour Inlet, New Zealand has smelter residues with up to 17 wt.% antimony. Residues include coarse tailings (cm scale particles, poorly sorted), sand tailings (well sorted) and smelter slag (blocks up to 30 cm across). All of this material has oxidised to some degree over the ca. 100 years since the site was abandoned. Oxidation has resulted in acidification of the residues down to pH 2-5. Smelter slag contains pyrrhotite (FeS) and metallic antimony, and oxidation is restricted to surfaces only. The coarse tailings are the most oxidised, and few sulfide grains persist. Unoxidised sand tailings contain 10-20 vol.% stibnite (Sb2S3) containing up to 5% As, with subordinate arsenopyrite (FeAsS), and minor pyrite (FeS2). The sand tailings are variably oxidised on a scale of 2-10 cm, but original depositional layering is preserved during oxidation and formation of senarmontite (Sb2O3). Oxidation of sand tailings has resulted in localised mobility of both Sb and As on the cm scale, resulting in redistribution of these metalloids with iron oxyhydroxide around sand grain boundaries. Experiments demonstrate that Sb mobility decreases with time on a scale of days. Attenuation of both As and Sb occurs due to adsorption on to iron oxyhydroxides which are formed during oxidation of the smelter residues. There is no detectable loss of Sb or As from the smelter site into the adjacent river, <50 m away, which has elevated Sb (ca. 20 microg/l) and As (ca. 7 microg/l) from mineralised rocks upstream. Despite the high concentrations of Sb and As in the smelter residues, these metalloids are not being released into the environment. PMID:14987811

  10. Characterization of Antimony exchanged Hydrous Zirconium oxide

    International Nuclear Information System (INIS)

    Pentavalent 125Sb bearing species are persistent even after chemical treatment in low level liquid waste effluents. It was found that Hydrous Zirconium Oxide (HZO) had an efficiency better that 80% for Sb pick in a wide pH range of 1-13 for concentrations up to 150 mg/l. HZO coated on poly urethane foam was used in WMD Trombay for removal for 125Sb from waste effluent. The exchange capacity of HZO with 40% moisture content ranged between 0.7-0.9 meq/g for removal of Sb(V). In order to understand the mechanism of Sb uptake by HZO, freshly prepared HZO exchanged with trivalent and pentavalent Sb from aqueous solutions was characterized with FTIR and XRD. The FTIR analysis confirmed presence of surface hydroxyl groups. Sb exchanged HZO samples showed modification in characteristic frequencies of -OH group when compared with unexchanged HZO. The broadening of -OH stretching frequency at 3400 cm-1 in Sb exchanged HZO-B indicated of ingress of disorderliness or weakening of -OH bond. The spectral shift was towards lower frequencies indicating clustering of low frequency bonds around -OH groups and weakening of -O-H bond. This change in -OH profile shows it to be the site of exchange/sorption. The XRD analysis showed HZO to be amorphous. Both pentavalent and trivalent antimony was exchanged with HZO, heat treated at 600℃ and analysed with XRD. Hydrous Zirconium Oxide (Heated up to 600℃) had an X-Ray diffraction pattern identical to Aldrich make pure Zirconia (Monoclinic) (PCPDF-371484). Pentavalent Sb loaded HZO and trivalent Sb loaded HZO showed different crystalline structures on heat treatment. Sb(V) loaded HZO shows Orthorhombic structure (PCCPDF-371413) and Sb(III) exchanged Zirconia shows tetragonal structure (PCPDF-501089). Cubic Sb2O5 antimony oxide crystals were also detected in the sample. From the above analysis it could be understood that the surface hydroxyl group helped in sorption of Sb species. But this was not purely surface phenomenon. Sb after

  11. Atomic scale properties of magnetic Mn-based alloys probed by Emission Mössbauer spectroscopy

    CERN Multimedia

    Mn-based alloys are characterized by a wealth of properties, which are of interest both from fundamental physics point of view and particularly attractive for different applications in modern technology: from magnetic storage to sensing and spin-based electronics. The possibility to tune their magnetic properties through post-growth thermal processes and/or stoichiometry engineering is highly important in order to target different applications (i.e. Mn$_{x}$Ga) or to increase their Curie temperature above room temperature (i.e. off-stoichiometric MnSi). In this project, the Mössbauer effect will be applied at $^{57}$Fe sites following implantation of radioactive $^{57}$Mn, to probe the micro-structure and magnetism of Mn-based alloys at the most atomic-scale. The proposed experimental plan is devoted to establish a direct correlation between the local structure and bulk magnetism (and other physical properties) of Mn-based alloys.

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

    Directory of Open Access Journals (Sweden)

    Min Zhu

    2013-10-01

    Full Text Available 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.

  13. The surface tension of liquid aluminium-based alloys

    International Nuclear Information System (INIS)

    In a systematic study, the surface tensions of the binary alloys Al-Fe and Al-Ni were investigated over a wide temperature and concentration range using electromagnetic levitation and the oscillating drop technique. Surface tensions were derived from the oscillation frequencies applying the formalism of Cummings and Blackburn. Temperature was measured by single-color pyrometry. Of particular interest in these alloys are melts corresponding to compositions of intermetallic phases, because potential ordering phenomena may influence all thermophysical properties. In both systems, an increase of the surface tension is observed at such concentrations. On the basis of partial excess Gibbs enthalpies, surface tensions can be calculated via the Butler equation and compared with experimental results. The agreement with our experimental data depends crucially on the quality of the thermodynamic potentials used. In addition, phenomenological models are also discussed, which describe the general trend correctly

  14. Dilatometer study of rapidly solidified aluminium-silicon based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Varga, B [University TRANSILVANIA, B-dul Eroilor nr. 29, 500036, Brasov (Romania); Fazakas, E; Hargitai, H [Inst. for Materials Science and Technology, Bay Z. Foundation, Fehervari ut, 130., H-1116 Budapest (Hungary); Varga, L K, E-mail: varga@szfki.h

    2009-01-01

    Aluminum-Silicon alloys are sought in a large number of automotive and aerospace applications due to their low coefficient of thermal expansion and high wear resistance. The present study focused on structural transformations as a function of the temperature of rapidly solidified hypereutectic Al{sub 100-x}Si{sub x} (x = 12, 22 and 40) alloys. Different structures out of equilibrium have been obtained after casting in sand, graphite and copper moulds and by melt spinning. The retained Si content in supersaturated alpha Al and the precipitation of Si is discussed in the light of the dilatometer studies [1, 2, 3] complemented by metallographic microscopy, XRD and DSC [4] measurements. A Kissinger analysis was used to determine the activation energy for the precipitation of supersaturated Si content.

  15. Fracture of niobium-base silicide coated alloy

    International Nuclear Information System (INIS)

    Mechanical properties and character of fracture of Nb-W-Mo-Zr-C alloy composition with complex by composition and structure silicide coating under different states of stage-by-stage coating are studied. Structural features, character of fracture from ductile to quasibrittle transcrystalline one and, respectively, the composition plasticity level are defined by interrelation of fracture processes in coating, matrix plastic flow and possibility and way of stress relaxation on their boundary

  16. Determination of antimony in environment samples by gas phase chemiluminescence detection following flow injection hydride generation and cryotrapping.

    Science.gov (United States)

    Ye, Yousheng; Sang, Jianchi; Ma, Hongbing; Tao, Guanhong

    2010-06-15

    A novel method for the determination of antimony in environmental samples was developed with gas phase chemiluminescence detection following flow injection hydride generation and cryotrapping. The stibine, generated from samples by borohydride reduction of antimony using flow injection technique, was separated by using a new gas-liquid separator, dried with an ice-salt cryogenic bath and concentrated in a glass U-tube immersed in liquid nitrogen. Re-vaporization of stibine based on its boiling point was achieved by allowing the tube to warm at room temperature. A gas phase chemiluminescence signal was produced during the ozonation of the hydride in a reflective chamber. Under optimal conditions, the proposed method was characterized by a wide linear calibration range from 1.0microgL(-1) to 10.0mgL(-1) with a detection limit of 0.18microgL(-1) (n=11). The relative standard deviation for 10.0microgL(-1) antimony was 3.56% (n=11) and the sampling rate was 15 samples h(-1). Blank signal was reduced by the purification of reagents and the interference from transition metal ions was eliminated by the addition of L-cysteine into samples. The method was applied to the determination of antimony in environmental samples with satisfactory results. PMID:20441930

  17. A cloud point extraction for spectrophotometric determination of ultra- trace antimony without chelating agent in environmental and biological samples

    International Nuclear Information System (INIS)

    We report on a simple, sensitive and reliable method for the cloud point extraction of antimony (Sb) and its subsequent spectrophotometric detection. It is based on the color reaction of Sb (III) with iodide in acidic medium and subsequent micelle-mediated extraction of tetraiodoantimonate using a non-ionic surfactant in the absence of any chelating agent. The effects of reaction and extraction parameters were optimized. The calibration plot is linear in the range of 0.80-95 ng mL-1 of antimony in the sample solution, with a regression coefficient (r) of 0.9994 (for n=9). The detection limit (at SNR=3) is 0.23 ng mL-1, and the relative standard deviations at 10 and 70 ng mL-1 of antimony are 3.32 and 1.85 % (at n=8), respectively. The method compared favorably to other methods and was applied to determine antimony in seawater, anti-leishmania drug (glucantime), and human serum. (author)

  18. Degradation mode survey of titanium-base alloys

    International Nuclear Information System (INIS)

    Of the materials reviewed, commercially pure titanium, Ti Gr 2, is the most susceptible to crevice corrosion. Ti Gr 7, 12, and 16 are likely to be resistant to crevice corrosion under the current expected Yucca Mountain repository conditions. Although Grade 7 has the greatest resistance to crevice corrosion it is also the most expensive. Although the possibility of sustained loads cracking exists, it has not yet been observed in a Ti alloys. For hydride precipitation to occur 100 degrees C, the hydrogen concentration would need to be relatively high, much higher than the maximum amount of hydrogen allowed during the manufacture of (α Ti alloys (0.0 15 wt%). A large amount of (SCC) stress corrosion cracking data accumulated at SNL and BNL for the WIPP program and by the Canadian Waste Management Program on titanium grades 2 and 12 indicates that there is no SCC at naturally occurring potentials in various brines. Hydride-induced cracking of titanium is a possibility and therefore, further investigation of this phenomenon under credible repository conditions is warranted. One disadvantage of titanium and its alloys is that their strengths decrease rather rapidly with temperature. This is due to the strong temperature dependence of interstitial solute strengthening mechanisms. Ti Gr 12 and 16 are recommended for further consideration as candidate materials for high level nuclear waste containers

  19. Development of rapidly solidified Al-Y-Ni-based alloys

    International Nuclear Information System (INIS)

    The present study is concerned with the effect of alloying additions (e.g. Co, Nb, Pd, La and Y) to the glass forming ability (GFA) of Al-Y-Ni alloys. Rapidly solidified ribbons of the following systems have been prepared by melt-spinning process: Al88Ni x/2Pd x/2Y12-x (x = 2, 5, 10), Al88Ni1Co1Y10-xLa x (x = 0, 5, 10), Al88Ni1Nb1Y10, and Al86Ni4-xCo xY10 (x = 1, 2, 3). Characterisation of the melt spun alloys was carried out through a combination of X-ray diffractometry, differential scanning calorimetry, and transmission electron microscopy. GFA in Al88Ni1TM1Y10 (where TM = Co, Nb, Pd) increases in the following order: Nb 88-Ni-Pd-Y systems the optimum quantity of yttrium is 10 at.%. A complete substitution of Y with La, or aluminium with 2 at.% of (Co,Ni) decreases the glass forming ability in Al88Ni1Co1Y10 but increases thermal stability of the residual amorphous phase. Partial replacement of Y with La significantly improves the thermal stability of the amorphous phase in Al-Ni-Co-Y

  20. Oxygen Behavior in Bulk Amorphous Zr-base Alloy

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Bulk Zr55Al10Ni5Cu30 metallic glass plates with a dimension of 85 mm×35mm×4 mm and a complicated plate werefabricated by injecting casting method using spongy zirconium and industrial purity aluminum, nickel and copper asraw materials. It was shown that the holding time of liquid metals at elevated temperatures had a great influence onthe oxygen content of the plates due to the contamination resulting from the atmosphere. Increasing holding timeresulted in the increase of oxygen content in the injected alloy. The glass transition temperatures of the bulk metallicglass plates are higher than that reported in the literature and crystallization temperature is lower for the one withhigher oxygen content at the same heating rate. The extension of the undercooled liquid region △Tx reaching about87 K is 3 K higher than that previously reported and 26 K higher than that with oxygen content of 0.076 wt pct forthe one with oxygen content as high as 0.065 wt pct. Therefore the oxygen content of the alloy has a significantinfluence on the glass forming ability and thermal stability of bulk metal glass. It is suggested that direct correlationbetween high glass forming ability and large △Tx is only valid for a well-defined Iow oxygen concentration or has tobe reconsidered by incorporating oxygen as an additional alloying element.

  1. Ageing dependence and martensite stabilization in copper based shape memory alloys

    International Nuclear Information System (INIS)

    Shape memory alloys exhibit a peculiar property called shape memory effect based on a first order solid state phase transformation, martensitic transformation which occurs in thermal manner on cooling the materials. Martensitic transformation is evaluated by the structural changes in microscopic scale. Copper-based ternary alloys exhibit shape memory effect in metastable beta phase region. These alloys have bcc-based ordered structures at high temperature, and transform martensiticaly to the long-period layered structures on cooling. The material atoms move cooperatively on (110)-type close packed planes of parent phase by means of a shear-like mechanism, and structural and fundamental properties of these alloys are altered by aging in the martensitic state. Therefore, the ageing gives rise to the structural changes in both long and short-range order in material. X-ray powder diffraction studies carried out in a long time interval on copper based shape memory alloys reveal that peak locations and intensities chance with ageing duration in martensitic condition, and these changes lead to the martensite stabilization in the redistribution or disordering manner, and stabilization proceeds by a diffusion-controlled process. (author)

  2. Ageing dependence and martensite stabilization in copper based shape memory alloys

    International Nuclear Information System (INIS)

    Shape memory alloys exhibit a peculiar property called shape memory effect based on a first order solid state phase transformation, martensitic transformation which occurs in thermal manner on cooling the materials. Martensitic transformation is evaluated by the structural changes in microscopic scale. Copper-based ternary alloys exhibit shape memory effect in metastable beta phase region. These alloys have bcc-based ordered structures at high temperature, and transform martensiticaly to the long-period layered structures on cooling. The material atoms move cooperatively on {110}-type close packed planes of parent phase by means of a shear-like mechanism, and structural and fundamental properties of these alloys are altered by aging in the martensitic state. Therefore, the ageing gives rise to the structural changes in both long and short-range order in material. X-ray powder diffraction studies carried out in a long time interval on copper based shape memory alloys reveal that peak locations and intensities chance with ageing duration in martensitic condition, and these changes lead to the martensite stabilization in the redistribution or disordering manner, and stabilization proceeds by a diffusion-controlled process

  3. Noninferiority of Miltefosine Versus Meglumine Antimoniate for Cutaneous Leishmaniasis in Children

    OpenAIRE

    Rubiano, Luisa Consuelo; Miranda, María Consuelo; Muvdi Arenas, Sandra; Montero, Luz Mery; Rodríguez-Barraquer, Isabel; Garcerant, Daniel; Prager, Martín; Osorio, Lyda; Rojas, Maria Ximena; Pérez, Mauricio; Nicholls, Ruben Santiago; Gore Saravia, Nancy

    2012-01-01

    Background. Children have a lower response rate to antimonial drugs and higher elimination rate of antimony (Sb) than adults. Oral miltefosine has not been evaluated for pediatric cutaneous leishmaniasis.

  4. Formation and crystallization kinetics of Nd-Fe-B-based bulk amorphous alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qiong; Ge, Hongliang; Zhang, Pengyue; Li, Dongyun; Wang, Zisheng [China Jiliang University, Magnetism Key Laboratory of Zhejiang Province, Hangzhou (China)

    2014-06-15

    In order to improve the glass-forming ability (GFA) of Nd-Fe-B ternary alloys to obtain fully amorphous bulk Nd-Fe-B-based alloy, the effects of Mo and Y doping on GFA of the alloys were investigated. It was found that the substitution of Mo for Fe and Y for Nd enhanced the GFA of the Nd-Y-Fe-Mo-B alloys. It was also revealed that the GFA of the samples was optimized by 4 at.% Mo doping and increased with theYcontent. The fully amorphous structures were all formed in the Nd{sub 6-x}Y{sub x}Fe{sub 68}Mo{sub 4}B{sub 22} (x =1-5) alloy rods with 1.5 mm-diameter. After subsequent crystallization, the devitrified Nd{sub 3}Y{sub 3}Fe{sub 68}Mo{sub 4}B{sub 22} alloy rod exhibited a uniform distribution of grains with a coercivity of 364.1 kA/m. The crystallization behavior of Nd{sub 3}Y{sub 3}Fe{sub 68}Mo{sub 4}B{sub 22} BMG was investigated in isothermal situation. The Avrami exponent n determined by JAM plot is lower than 2.5, implying that the crystallization is mainly governed by a growth of particles with decreasing nucleation rate. (orig.)

  5. Structure and mechanical properties of Ti-5Cr based alloy with Mo addition

    International Nuclear Information System (INIS)

    The effects of molybdenum (Mo) on the structure and mechanical properties of a Ti-5Cr-based alloy were studied with an emphasis on improving its strength/modulus ratio. Commercially pure titanium (c.p. Ti) was used as a control. As-cast Ti-5Cr and a series of Ti-5Cr-xMo (x = 1, 3, 5, 7, 9 and 11 wt.%) alloys were prepared by using a commercial arc-melting vacuum-pressure casting system, and investigated with X-ray diffraction (XRD) for phase analysis. Three-point bending tests were performed to evaluate the mechanical properties of all specimens and their fractured surfaces were observed by using scanning electron microscopy (SEM). The experimental results indicated that Ti-5Cr-7Mo, Ti-5Cr-9Mo and Ti-5Cr-11Mo alloys exhibited ductile properties, and the β-phase Ti-5Cr-9Mo alloy exhibited the lowest bending modulus. However, the Ti-5Cr-3Mo and Ti-5Cr-5Mo alloys had much higher bending moduli due to the formation of the ω phase during quenching. It is noteworthy that the Ti-5Cr-9Mo alloy exhibited the highest bending strength/modulus ratios at 26.0, which is significantly higher than those of c.p. Ti (8.5) and Ti-5Cr (13.3). Furthermore, the elastically recoverable angle of the Ti-5Cr-9Mo alloy (30o) was greater than that of c.p. Ti (2.7o). The reasonably high strength (or high strength/modulus ratio) β-phase Ti-5Cr-9Mo alloy exhibited a low modulus, ductile property, and excellent elastic recovery capability, which qualifies it as a novel implant materials.

  6. An Experimental Study on Rate-sensitive Tensile Deformation Behaviour of Fe-based Shape Memory Alloy

    OpenAIRE

    Iwamoto Takeshi; Fujita Kazuki

    2015-01-01

    Recently, it is attempted to apply high manganese steel including Fe-based shape memory alloy to vibration dampers. Especially, the alloy indicates a special characteristic as a well-known shape memory effect. By coupling between this effect and its plastic deformation, it can be considered that its deformation behaviour at higher deformation rate becomes quite complicated and still unclear. In this study, tensile tests of Fe-based shape memory alloy at different rate of deformation are condu...

  7. The mode of stress corrosion cracking in Ni-base alloys in high temperature water containing lead

    International Nuclear Information System (INIS)

    The mode of stress corrosion cracking (SCC) in Ni-base alloys in high temperature aqueous solutions containing lead was studied using C-rings and slow strain rate testing (SSRT). The lead concentration, pH and the heat treatment condition of the materials were varied. TEM work was carried out to observe the dislocation behavior in thermally treated (TT) and mill annealed (MA) materials. As a result of the C-ring test in 1M NaOH+5000 ppm lead solution, intergranular stress corrosion cracking (IGSCC) was found in Alloy 600MA, whereas transgranular stress corrosion cracking (TGSCC) was found in Alloy 600TT and Alloy 690TT. In most solutions used, the SCC resistance increased in the sequence Alloy 600MA, Alloy 600TT and Alloy 690TT. The number of cracks that was observed in alloy 690TT was less than in Alloy 600TT. However, the maximum crack length in Alloy 690TT was much longer than in Alloy 600TT. As a result of the SSRT, at a nominal strain rate of 1 x 10-7/s, it was found that 100 ppm lead accelerated the SCC in Alloy 600MA (0.01%C) in pH 10 at 340 C. IGSCC was found in a 100 ppm lead condition, and some TGSCC was detected on the fracture surface of Alloy 600MA cracked in the 10000 ppm lead solution. The mode of cracking for Alloy 600 and Alloy 690 changed from IGSCC to TGSCC with increasing grain boundary carbide content in the material and lead concentration in the solution. IGSCC seemed to be retarded by stress relaxation around the grain boundaries, and TGSCC in the TT materials seemed to be a result of the crack blunting at grain boundary carbides and the enhanced Ni dissolution with an increase of the lead concentration. (orig.)

  8. Synthesis and Performance of Fe-based Amorphous Alloys for Nuclear Waste Applications

    International Nuclear Information System (INIS)

    Recent developments in multi-component Fe-based amorphous alloys have shown that these novel materials exhibit outstanding corrosion resistance compared to typical crystalline alloys such as high-performance stainless steels and Ni-based C-22 alloy. During the past decade, amorphous alloy synthesis has advanced to allow for the casting of bulk metallic glasses. In several Fe-based alloy systems it is possible to produce glasses with cooling rates as low as 100 K/s. At such low cooling rates, there is an opportunity to produce amorphous solids through industrial processes such as thermal spray-formed coatings. Moreover, since cooling rates in typical thermal spray processing exceed 1000 K/s, novel alloy compositions can be synthesized to maximize corrosion resistance (i.e. adding Cr and Mo) and to improve radiation compatibility (adding B) and still maintain glass forming ability. The applicability of Fe-based amorphous coatings in typical environments where corrosion resistance and thermal stability are critical issues has been examined in terms of amorphous phase stability and glass-forming ability through a coordinated computational analysis and experimental validation. For example, a wedge casting technique has been applied to examine bulk glass forming alloys by combining multiple thermal probes with a measurement based kinetics analysis and a computational thermodynamics evaluation to elucidate the phase selection competition and critical cooling rate conditions. Based upon direct measurements and kinetics modeling it is evident that a critical cooling rate range should be considered to account for nucleation behavior and that the relative heat flow characteristics as well as nucleation kinetics are important in judging ease of glass formation. Similarly, a novel computational thermodynamics approach has been developed to explore the compositional sensitivity of glass-forming ability and thermal stability. Also, the synthesis and characterization of alloys

  9. Corrosion and mechanical property at high temperature of nickel based alloy for VHTR

    International Nuclear Information System (INIS)

    Using a very high temperature reactor (VHTR), it is conceptually and practically possible to generate highly efficient electricity and produce massive hydrogen among generation IV nuclear power plants. The structural material for an intermediate heat exchanger (IHX) is exposed to high temperature of up to 950 .deg. C. In this harsh environment, nickel-based alloys such as Alloy 617 and Haynes 230 are considered as promising candidate materials for IHX material owing to their excellent creep resistances at high temperature. However, high-temperature degradation cannot be avoided even for nickel-based alloy. Helium which inevitably includes impurities such as H2, CH4, H2O and CO is used as a coolant in a VHTR. Material degradation is aggravated by corrosion under an impure helium environment, which is one of the main obstacles to overcome for the application and successful long-term operation of a VHTR. A review of the thermodynamics indicates which reactions are available on the surface of the materials among oxidation, carburization and decarburization, but it does not give US the kinetic preference. This kinetic preference can induce localized corrosion, kinetic irreversibility and long-term material instability leading to material degradation. In addition to a long-term corrosion test under a VHTR coolant environment, the development of new alloys superior to commercial nickel-based alloy also give way to the successful establishment of a VHTR. Commercial nickel-based wrought alloy is strengthened by a solid solution and precipitation hardening mechanism in a wide temperature range of 500 to 900 .deg. C. The γ' significantly contributes to the strengthening by locking dislocation motion by an antiphase boundary at an intermediate temperature range of 700 to 800 .deg. C, but is no longer stable above this temperature range. However, the material for an IHX needs to fulfill the mechanical property requirements in a narrow and very high temperature range of 850 to

  10. Interface structure and formation mechanism of diffusion-bonded joints of TiAl-based alloy to titanium alloy

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Vacuum diffusion bonding of a TiAl-based alloy (TAD) to a titanium alloy (TC2) was carried out at 1 273 K for 15~120 min under a pressure of 25 MPa. The kinds of the reaction products and the interface structures of the joints were investigated by SEM, EPMA and XRD. Based on this, a formation mechanism of the interface structure was elucidated. Experimental and analytical results show that two reaction layers have formed during the diffusion bonding of TAD to TC2. One is Al-rich α(Ti)layer adjacent to TC2,and the other is (Ti3Al+TiAl)layer adjacent to TAD,thus the interface structure of the TAD/TC2 joints is TAD/(Ti3Al+TiAl)/α(Ti)/TC2.This interface structure forms according to a three-stage mechanism,namely(a)the occurrence of a single-phase α(Ti)layer;(b)the occurrence of a duplex-phase(Ti3Al+TiAl)layer;and(c)the growth of the α(Ti)and (Ti3Al+TiAl)layers.

  11. Design and development of powder processed Fe-P based alloys

    International Nuclear Information System (INIS)

    Highlights: → The forming technique does not require any binder. Thus the system remains uncontaminated. → The use of ceramic protective coating eliminates the need of hydrogen protective atmosphere during heating. → Combined application of glassy ceramic coating and use of graphite as a reducing agent has lead to economy in P/M processing. → The technology developed in the present investigation showed very low coercivity and total loss values. -- Abstract: The present investigation deals with designing Fe, Fe-P binary and Fe-P-Si ternary alloys produced by an in-house developed powder metallurgical technique based on 'Hot Powder Preform Forging'. Proper soaking of preforms at high temperature (1050 oC) eliminates iron-phosphide eutectic and brings entire phosphorus into solution in iron. Attempting hot forging thereafter completely eliminates hot as well as cold shortness and thereby helps to form these preforms (alloys) into very thin sheets of 0.5 mm. The use of costly hydrogen atmosphere during sintering has been eliminated by the addition of carbon as a reducing agent to form CO gas within the compact by reacting with oxygen of iron powder particles. The glassy ceramic coating applied over the compact serves as a protective coating to avoid atmospheric oxygen attack over the compact held at high temperature. These alloys so formed were subjected to density examination at various stages. Microstructural study has been carried out to estimate the grain size, volume percentage of porosity in the alloys, and uniform distribution of phosphorus and silicon in an iron matrix. X-ray diffraction studies of these alloys revealed the presence of only ferrite as product phase. Addition of alloying elements such as P and Si has improved the resistivity and magnetic properties of iron. Fe-0.07C-0.2O-0.3P-0.5Si alloy showed a resistivity as high as 31.7 μΩ cm. Coercivity values of the alloys ranged from 0.51 to 1.98 Oe. The total magnetic loss of Fe-0.07C-0.2O-0.3P

  12. Room temperature synthesis of Ni-based alloy nanoparticles by radiolysis.

    Energy Technology Data Exchange (ETDEWEB)

    Nenoff, Tina Maria; Berry, Donald T.; Lu, Ping; Leung, Kevin; Provencio, Paula Polyak; Stumpf, Roland Rudolph; Huang, Jian Yu; Zhang, Zhenyuan

    2009-09-01

    Room temperature radiolysis, density functional theory, and various nanoscale characterization methods were used to synthesize and fully describe Ni-based alloy nanoparticles (NPs) that were synthesized at room temperature. These complementary methods provide a strong basis in understanding and describing metastable phase regimes of alloy NPs whose reaction formation is determined by kinetic rather than thermodynamic reaction processes. Four series of NPs, (Ag-Ni, Pd-Ni, Co-Ni, and W-Ni) were analyzed and characterized by a variety of methods, including UV-vis, TEM/HRTEM, HAADF-STEM and EFTEM mapping. In the first focus of research, AgNi and PdNi were studied. Different ratios of Ag{sub x}- Ni{sub 1-x} alloy NPs and Pd{sub 0.5}- Ni{sub 0.5} alloy NP were prepared using a high dose rate from gamma irradiation. Images from high-angle annular dark-field (HAADF) show that the Ag-Ni NPs are not core-shell structure but are homogeneous alloys in composition. Energy filtered transmission electron microscopy (EFTEM) maps show the homogeneity of the metals in each alloy NP. Of particular interest are the normally immiscible Ag-Ni NPs. All evidence confirmed that homogeneous Ag-Ni and Pd-Ni alloy NPs presented here were successfully synthesized by high dose rate radiolytic methodology. A mechanism is provided to explain the homogeneous formation of the alloy NPs. Furthermore, studies of Pd-Ni NPs by in situ TEM (with heated stage) shows the ability to sinter these NPs at temperatures below 800 C. In the second set of work, CoNi and WNi superalloy NPs were attempted at 50/50 concentration ratios using high dose rates from gamma irradiation. Preliminary results on synthesis and characterization have been completed and are presented. As with the earlier alloy NPs, no evidence of core-shell NP formation occurs. Microscopy results seem to indicate alloying occurred with the CoNi alloys. However, there appears to be incomplete reduction of the Na{sub 2}WO{sub 4} to form the W

  13. The size-effect on the formation enthalpy of nanosized binary ti based alloy

    International Nuclear Information System (INIS)

    The effects of grain size and composition on the formation enthalpy of nano binary Ti-based alloy are investigated by taking the surface effect into account within the modified Miedema model. It is demonstrated that the formation enthalpy of binary Ti based alloy with nano grains is size-dependent and exhibits evident size-effects. The formation enthalpy increases with the size decrease, and its value turns from negative to positive at a critical size, which will weaken the thermal stability of the nano grains. Furthermore, the composition segregation taking place in the nano grains of the Ti based alloy is obvious when the grain size is less than 10 nm and the tendency of segregation is dependent on the surface formation enthalpy of nanoparticle. (authors)

  14. An X-ray Fourier line shape analysis in cold-worked hexagonal titanium base alloys

    International Nuclear Information System (INIS)

    X-ray diffraction is an established technique for the analysis of microstructural parameters such as domain sizes, microstrains within the domains, and deformation fault densities in the deformed state of metals and alloys. These microstructural parameters influence the flow of dislocation in the lattice under deformation and thus regulate the strength and hardenability of the materials. The evaluation of such microdefects is this necessary for understanding the mechanical behavior of materials. In the present study, considering the wide applicability of titanium-base alloys in aviation industry, two alloy systems, i.e., titanium-base aluminum and titanium-base zirconium, have been selected. A number of X-ray diffraction profiles belonging to both fault-affected (H - K = 3N ± 1) and fault-unaffected (H - K = 3N) reflections have been recorded by a SIEMENS Kristolloflex-4 diffractometer using Cu Kα radiation, and the profiles have been analyzed to evaluate the microstructural parameters

  15. Recovery of antimony-125 from tin-124 irradiated by neutrons

    International Nuclear Information System (INIS)

    Currently, antimony-125 is produced by recovery from tin-124 irradiated by neutrons in nuclear reactors. The radionuclide builds up following the pathway: Sn-124 (n,γ) → Sn-125 (β-) (9.6 days) → Sb-125 ((β-) (2.77 years) The cross-section of the (n,γ) reaction is low (0.2 barn), therefore tin metal enriched with tin-124 is used. It should be noted that the use of an enriched target decreases the build-up of other radionuclides as compared to the natural mixture of tin isotopes. Published data showed that ion exchange on anion exchangers is one of the most promising procedures of recovery of antimony-125 from irradiated tin-124. We irradiated tin metal enriched with tin-124 (approximately 96%). After cooling and storage, the specific activity was 5 μCi per g of metal. The irradiated sample was dissolved in concentrated hydrochloric acid containing hydrogen peroxide or bromine in order to convert tin to the tetravalent state and antimony to the pentavalent state. We used tin-119m as a mark for an express gamma-spectrometric determination of the distribution coefficients. We studied the separation of Sb-125 and tin on strongly basic (Dowex-50 and AV-17), moderately basic (AN-2FN), and weakly basic (AN-31) ion exchangers. Hydrochloric acid, a mixture of hydrochloric and hydrobromic acids, and nitric acid were used as the elutriating agents. The samples from chromatography were subjected to gamma-spectrometric analysis using Si(Li) and Ge(Li) semiconductor detectors. In experiments examining the separation on strongly basic anion exchangers, the attained decontamination factor for removal of tin from antimony-125 was approximately 104-105 in one cycle. In the experiments devoted to the separation on moderately basic and weakly basic anion exchangers, tin was eluted before antimony-125. This should improve reasonably the regeneration of the enriched tin samples. The most interesting and significant results were obtained in the study of separation of antimony-125

  16. Oral Delivery of Meglumine Antimoniate-β-Cyclodextrin Complex for Treatment of Leishmaniasis

    OpenAIRE

    Demicheli, Cynthia; Ochoa, Rosemary; da Silva, José B. B.; Falcão, Camila A. B.; Rossi-Bergmann, Bartira; Melo, Alan L.; Sinisterra, Ruben D.; Frézard, Frédéric

    2004-01-01

    The need for daily parenteral administration represents one of the most serious limitations in the clinical use of pentavalent antimonials against leishmaniasis. In this work, we investigated the ability of β-cyclodextrin to enhance the oral absorption of antimony and to promote the oral efficacy of meglumine antimoniate against experimental cutaneous leishmaniasis. The occurrence of interactions between β-cyclodextrin and meglumine antimoniate was demonstrated through the changes induced in ...

  17. The influence of pet containers on antimony concentration in bottled drinking water

    OpenAIRE

    Perić-Grujić Aleksandra A.; Radmanovac Aleksandar R.; Stojanov Aleksander M.; Pocajt Viktor V.; Ristić Mirjana Đ.

    2010-01-01

    Antimony trioxide (Sb2O3) is the most frequently used catalyst in the polyethylene terephthalate (PET) manufacture. As a result, antimony is incorporated into PET bottles at concentration level of 100-300 mg/kg. PET containers are used for drinking water and beverages, as well as food packaging and in the pharmaceutical industry. Thus, it is important to understand the factors that may influence the release of antimony from the catalysts into water and other products, since antimony is potent...

  18. The influence of pet containers on antimony concentration in bottled drinking water

    Directory of Open Access Journals (Sweden)

    Perić-Grujić Aleksandra A.

    2010-01-01

    Full Text Available Antimony trioxide (Sb2O3 is the most frequently used catalyst in the polyethylene terephthalate (PET manufacture. As a result, antimony is incorporated into PET bottles at concentration level of 100-300 mg/kg. PET containers are used for drinking water and beverages, as well as food packaging and in the pharmaceutical industry. Thus, it is important to understand the factors that may influence the release of antimony from the catalysts into water and other products, since antimony is potentially toxic trace element. In this paper, the antimony content in nine brands of bottled mineral and spring water from Serbia, and seven brands of bottled mineral and spring water from EU countries was analyzed. The measurements were conducted using the inductively coupled plasma-mass spectrometry (ICP-MS technique. In the all examined samples the antimony concentration was bellow the maximum contaminant level of 5 μg/L prescribed by the Serbian and EU regulations. Comparison of the content of antimony in PET bottled waters with the content of antimony in water bottled commercially in glass and the natural content of antimony in pristine groundwaters, provides explicit evidence of antimony leaching from PET containers. Since waters bottled in PET have much greater concentration ratio of Sb to Pb than corresponding pristine groundwaters, it can be assumed that bottled waters cannot be used as the relavant source for the study of the natural antimony content in groundwaters. There is a clear relation between the quality of water in bottles (composition, ion strength and antimony leaching rate. Moreover, while the rate of antimony leaching is slow at temperatures below 60 oC, at the temperature range of 60-80 oC antimony release occurs and reaches maximum contaminant level rapidly. As antimony can cause both acute and chronic health problems, factors that promote the increase of antimony concentration should be avoided.

  19. Vanadium alloys: development strategy

    International Nuclear Information System (INIS)

    A strategy for the development of vanadium alloys for use in radiation environments is outlined. An attractive reference alloy (V-15Cr-5Ti) has been identified. The critical issues in developing vanadium base alloys are summarized

  20. Behavior of arsenic impurity at antimony electric precipitation

    International Nuclear Information System (INIS)

    In the paper the arsenic impurity electrochemical behavior and it purification from antimony by electric precipitation out of fluoride solutions was studied. For this the arsenic sample with mass 0.003-0.006 g has been irradiated at the WWR-SM nuclear reactor during 3-5 hour in the thermal neutron flux 1013 n/cm2 s, after 24 h keeping the sample has being dissolved in the concentrated nitric acid, and then it has been evaporated several times with distillation water addition up to wet precipitation state. It is shown, that arsenic impurity behavior character in the antimony electric precipitation out to fluoride electrolyte depends on the electrolyte content, electrolysis conditions, arsenic valency state in arsenic impurity existence in the five-valency state its joint electric reduction with antimony is practically not observing. In the case the arsenic being in three-valency state, it joint electric reduction with antimony is taking place. In this time the electrolytic antimony contents arsenic impurities less in dozen time than initial material

  1. Rare earth-Mg-Ni-based hydrogen storage alloys as negative electrode materials for Ni/MH batteries

    International Nuclear Information System (INIS)

    Research highlights: → State-of-the-art of new R-Mg-Ni-based hydrogen storage electrode alloys is reviewed. → Electrode performances of the R-Mg-Ni-based alloys depend strongly on the stoichiometric ratio, alloy components and microstructure. → Optimized alloy compositions contain mainly metallic elements of La, Mg, Ni, Co, Mn and Al. → Pulverization of particles and oxidation/corrosion of active components are responsible for the fast capacity degradation. → Low-Co or Co-free R-Mg-Ni-based electrode alloys should be developed. - Abstract: This review is devoted to new rare earth-Mg-Ni-based (R-Mg-Ni-based) hydrogen storage alloys that have been developed over the last decade as the most promising next generation negative electrode materials for high energy and high power Ni/MH batteries. Preparation techniques, structural characteristics, gas-solid reactions and electrochemical performances of this system alloy are systematically summarized and discussed. The improvement in electrochemical properties and their degradation mechanisms are covered in detail. Optimized alloy compositions with high discharge capacities, good electrochemical kinetics and reasonable cycle lives are described as well. For their practical applications in Ni/MH batteries, however, it is essential to develop an industrial-scale homogeneous preparation technique, and a low-cost R-Mg-Ni-based electrode alloy (low-Co or Co-free) with high discharge capacity, long cycle life and good kinetics.

  2. Comparative evaluation of the effect of simulated porcelain firing cycle on the mechanical properties and microstructure of base metal ceramic alloys.

    OpenAIRE

    Singla A; Shetty P; Joseph M; Kotian R

    1999-01-01

    A comparison of mechanical properties and microstructure of four metal ceramic alloys in as-cast and heat-treated conditions resulted in significant differences. The alloys that were tested included two nickel-based and two cobalt-based metal ceramic alloys. Mechanical properties tested included strength, percent elongation and hardness. Ten tensile bars were cast for each alloy. Five of the ten bars for each alloy were randomly selected for heat treatment with the simulated porcelain firing ...

  3. Effects of can parameters on canned-forging process of TiAl base alloy(Ⅰ)--Microstructural analyses

    Institute of Scientific and Technical Information of China (English)

    刘咏; 韦伟峰; 黄伯云; 何双珍; 周科朝; 贺跃辉

    2002-01-01

    By using thermal simulation technique, the conventional canned-forging process of TiAl based alloy was studied. The effect of can parameters on the microstruct ures of TiAl alloy was analyzed in this process. The results show that, the defo rmation microstructure of TiAl based alloy without canning is inhomogeneous. In lateral area, crack and shearing lines can be found; while in central area, fine -grained shearing zone can be found. The effect of can is to reduce the seconda ry tensile stress. However, only when the deformation of the steel can is coinci dental with that of TiAl alloy ingot, can this effect be effective. Moreover, a thick can would enhance the microstructural homogeneity in TiAl based alloy. With the H/D ratio of the ingot increasing, the deformation of TiAl alloy would be more unsteady, therefore, a thicker can should be needed.

  4. Influence of Cumulative Plastic Deformation on Microstructure of the Fe-Al Intermetallic Phase Base Alloy

    Directory of Open Access Journals (Sweden)

    Bednarczyk I.

    2014-10-01

    Full Text Available This article is part of the research on the microstructural phenomena that take place during hot deformation of intermetallic phase-based alloy. The research aims at design an effective thermo - mechanical processing technology for the investigated intermetallic alloy. The iron aluminides FeAl have been among the most widely studied intermetallics because their low cost, low density, good wear resistance, easy of fabrication and resistance to oxidation and corrosion. There advantages create wide prospects for their industrial applications for components of machines working at a high temperature and in corrosive environment. The problem restricting their application is their low plasticity and their brittle cracking susceptibility, hampers their development as construction materials. Consequently, the research of intermetallic-phase-based alloys focuses on improvement their plasticity by hot working proceses. The study addresses the influence of deformation parameters on the structure of an Fe-38% at. Al alloy with Zr, B Mo and C microadditions, using multi – axis deformation simulator. The influence of deformation parameters on microstructure and substructure was determined. It was revealed that application of cumulative plastic deformation method causes intensive reduction of grain size in FeAl phase base alloy.

  5. Effects of AI Addition on the Thermoelectric Properties of Zn-Sb Based Alloys

    Institute of Scientific and Technical Information of China (English)

    CUI Jiaolin; LIU Xianglian; YANG Wei; CHEN Dongyong; MAO Liding; QIAN Xin

    2009-01-01

    The β-Zn4Sb3, emerged as a compelling p-type thermoelectric material, is widely used in heat-electricity conversion in the 400-650 K range. In order to probe the effects of slight doping on the crystal structure and physical properties, we prepared the samples of Al-added Zn-Sb based alloys by spark plasma sintering and evaluated their microstructures and thermoelectric properties. After a limited Al addition into the Zn-Sb based alloys we observed many phases in the alloys, which include a major phase β-Zn4Sb3,intermetallic phases ZnSb and AISb. The major β-Zn4Sb3 phase plays a fundamental role in controlling the thermoelectric performance, the precipitated phases ZnSb and AISb are of great importance to tailor the transport properties, such as the gradual enhancement of lattice thermal conductivity, in spite of an increased phonon scattering in additional grain boundaries. The highest thermoelectric figure of merit of 0.55 is obtained for the alloy with a limited AI addition at 653 K, which is 0.08 higher than that of un-doped β-Zn4Sb3 at the corresponding temperature. Physical property experiments indicate that there is a potentiality for the improvement of thermoelectric properties if a proper elemental doping is carried out into the Zn-Sb based alloys, which was confirmed by AI addition in the present work.

  6. Shear bond strength of a ceromer to noble and base metal alloys

    Directory of Open Access Journals (Sweden)

    Dorriz H.

    2006-08-01

    Full Text Available Background and Aim: The improvement of the physical and chemical properties of resins as well as great advances achieved in the field of chemical bonding of resin to metal has changed the trend of restorative treatments. Today the second generation of laboratory resins have an important role in the restoration of teeth. The clinical bond strength should be reliable in order to gain successful results. In this study the shear bond strength (SBS between targis (a ceromer and two alloys (noble and base metal was studied and the effect of thermocycling on the bond investigated. Materials and Methods: In this experimental study, alloys samples were prepared according to the manufacturer. After sandblasting of bonding surfaces with 50µ AI2o3 Targis was bonded to the alloy using Targis I link. All of the samples were placed in 37°C water for a period of 24 hours. Then half of the samples were subjected to 1000 cycles of thermocycling at temperatures of 5°C and 55°C. Planear shear test was used to test the bond strength in the Instron machine with the speed rate of 0.5mm/min. Data were analyzed by SPSS software. Two-way analysis of variance was used to compare the bond strength among the groups. T test was used to compare the alloys. The influence of thermocycling and alloy type on bond strength was studied using Mann Whitney test. P<0.05 was considered as the limit of significance. Result: The studied alloys did not differ significantly, when the samples were not thermocycled (P=0.136 but after thermocycling a significant difference was observed in SBS of resin to different alloys (P=000.1. Thermal stress and alloy type had significant interaction, with regard to shear bond strength (P=0.003. There was a significant difference in SBS before and after thermocycling in noble alloys (P=0.009, but this was not true in base metals (P=0.29. Maximum SBS (19.09 Mpa belonged to Degubond 4, before thermocycling. Minimum SBS (8.21 Mpa was seen in Degubond 4

  7. High Temperature Oxidation and Electrochemical Investigations on Ni-base Alloys

    OpenAIRE

    Obigodi-Ndjeng, Marthe Georgia

    2011-01-01

    This study examined high-temperature oxidation behavior of different Ni-base alloys. In addition, electrochemical characterization of the alloy’s corrosion behavior was carried out, including comparison of the properties of native passive films grown at room temperature and high temperature oxide scales. PWA 1483 (single-crystalline Ni-base superalloy) and model alloys Ni-Cr-X (where X is either Co or Al) were oxidized at 800 and 900 °C in air for different time periods. The superalloy showed...

  8. AFM research on the mechanism of Fe-based alloy stress annealed inducing magnetic anisotropy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The cross-section of the Fe-based alloy (Fe73.5Cu1Nb3Si13.5B9) ribbon annealed at 540℃ under various tensile stress was investigated with atomic force microscope (AFM). The stress effect mechanism in Fe-based alloy ribbon tensile stress an-nealed inducing transverse magnetic anisotropy field was studied using the X-ray diffraction spectra and longitudinal drive giant magneto-impedance effect curves, and the model of direction dominant in encapsulated grain agglomeration was es-tablished. The relationship between the direction dominant in encapsulated grain agglomeration and magnetic anisotropy field was disclosed.

  9. A corrosion resistant cerium oxide based coating on aluminum alloy 2024 prepared by brush plating

    International Nuclear Information System (INIS)

    Cerium oxide based coatings were prepared on AA2024 Al alloy by brush plating. The characteristic of this technology is that hydrogen peroxide, which usually causes the plating solution to be unstable, is not necessary in the plating electrolyte. The coating showed laminated structures and good adhesive strength with the substrate. X-ray diffraction and X-ray photoelectron spectroscopy analysis showed that the coatings were composed of Ce(III) and Ce(IV) oxides. The brush plated coatings on Al alloys improved corrosion resistance. The influence of plating parameters on structure and corrosion resistance of the cerium oxide based coating was studied.

  10. A corrosion resistant cerium oxide based coating on aluminum alloy 2024 prepared by brush plating

    Energy Technology Data Exchange (ETDEWEB)

    Tang Junlei; Han Zhongzhi [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Zuo Yu, E-mail: zuoy@mail.buct.edu.cn [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Tang Yuming [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2011-01-15

    Cerium oxide based coatings were prepared on AA2024 Al alloy by brush plating. The characteristic of this technology is that hydrogen peroxide, which usually causes the plating solution to be unstable, is not necessary in the plating electrolyte. The coating showed laminated structures and good adhesive strength with the substrate. X-ray diffraction and X-ray photoelectron spectroscopy analysis showed that the coatings were composed of Ce(III) and Ce(IV) oxides. The brush plated coatings on Al alloys improved corrosion resistance. The influence of plating parameters on structure and corrosion resistance of the cerium oxide based coating was studied.

  11. Formation and Oxidation Resistance of Silicide Coatings for Mo and Mo-Based Alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The forming process of silicide coatings on pure Mo and Mo-base alloys, obtained by the gasphase deposition method, has been studied by examining the microstructure of coatings and the relationship between coating thickness and process parameters. It was shown that the growth of coatings was diffusion-controlled, the diffusion of silicon to be coated into Mo or Mo-base alloys was mainly responsible for the formation of silicide. The relationship between initial silicide thickness and oxidation resistance was also investigated, and the equation of service life of the coatings at high temperature in air is presented.

  12. Thermodynamic properties of lanthanum in gallium-indium eutectic based alloys

    OpenAIRE

    Shchetinskiy, A. V.; Dedyukhin, A. S.; Volkovich, V. A.; Yamshchikov, L. F.; Maisheva, A. I.; Osipenko, A. G.; Kormilitsyn, M. V.

    2013-01-01

    Activity and activity coefficients of lanthanum were determined for the first time in gallium-indium eutectic based alloys in a wide temperature range employing electromotive force method. Activity of β-La and super cooled liquid lanthanum in Ga-In eutectic based alloys between 573 and 1073 K linearly depends on the reciprocal temperature: lgaβ-La(Ga-In)=5.660-15, 352T±0.093 lgaLa(Ga-In)=6.074-15,839T±0.093 Activity coefficients of β-La and super cooled liquid lanthanum in this system at 617-...

  13. Novel Zn-based alloys for biodegradable stent applications: Design, development and in vitro degradation.

    Science.gov (United States)

    Mostaed, E; Sikora-Jasinska, M; Mostaed, A; Loffredo, S; Demir, A G; Previtali, B; Mantovani, D; Beanland, R; Vedani, M

    2016-07-01

    The search for a degradable metal simultaneously showing mechanical properties equal or higher to that of stainless steel and uniform degradation is still an open challenge. Several magnesium-based alloys have been studied, but their degradation rate has proved to be too fast and rarely homogeneous. Fe-based alloys show appropriate mechanical properties but very low degradation rate. In the present work, four novel Zn-Mg and two Zn-Al binary alloys were investigated as potential biodegradable materials for stent applications. The alloys were developed by casting process and homogenized at 350°C for 48h followed by hot extrusion at 250°C. Tube extrusion was performed at 300°C to produce tubes with outer/inner diameter of 4/1.5mm as precursors for biodegradable stents. Corrosion tests were performed using Hanks׳ modified solution. Extruded alloys exhibited slightly superior corrosion resistance and slower degradation rate than those of their cast counterparts, but all had corrosion rates roughly half that of a standard purity Mg control. Hot extrusion of Zn-Mg alloys shifted the corrosion regime from localized pitting to more uniform erosion, mainly due to the refinement of second phase particles. Zn-0.5Mg is the most promising material for stent applications with a good combination of strength, ductility, strain hardening exponent and an appropriate rate of loss of mechanical integrity during degradation. An EBSD analysis in the vicinity of the laser cut Zn-0.5Mg tube found no grain coarsening or texture modification confirming that, after laser cutting, the grain size and texture orientation of the final stent remains unchanged. This work shows the potential for Zn alloys to be considered for stent applications. PMID:27062241

  14. Preparation and characterization of aluminum based alloy - mica composites

    International Nuclear Information System (INIS)

    In this work, six pallets each of 2.0 cm dia and 0.5 cm thickness were prepared by powder metallurgy; half of them also contained 1% mica-powder to form a composite. Inclusion of mica resulted in a decreased density and an increased porosity of the sample. Brinell hardness was found to be 21% less for the composite than for the pure alloy. Micro-graphs of different areas of the sample show uniform distribution of mica particles and avoids around them. (author)

  15. Glass forming ability of iron based amorphous alloys depending on Mo, Cr and Co content

    International Nuclear Information System (INIS)

    The Fe41Co7Cr15Mo14C15B6Y2 multicomponent Fe-based alloy is known to be one of the best glass formers in iron-based systems and shows a critical casting thickness of 16 mm. The elements constituting the alloy have different influences on the glass forming ability. Therefore, the content of Mo, Cr and Co was systematically changed in the master alloy Fe77-x(Co,Cr,Mo)xC15B6Y2 to investigate how these three elements support the glassy microstructure. It was found that a certain content of Mo, Cr, and Co leads to a microstructure of amorphous matrix and α-Fe precipitates without any carbides.

  16. Crack growth rates for Ni--base alloys with the application to an operating BWR

    International Nuclear Information System (INIS)

    To perform adequate safety assessments of primary components in operating BWRs Crack Growth Rates (CGR) for Stress Corrosion Cracking in Normal Water Chemistry (NWC) as well as Hydrogen Water Chemistry (HWC) are needed. The data behind NUREG 0313 rev 2 was based on laboratory testing of sensitized stainless steels in oxygenated water. This so called NUREG-line overestimates CGRs for operating BWRs with respect to todays specification for water chemistry. In order to suggest new CGRs for Ni-base-alloys in the span from NWC to HWV we performed a literature review. Alloy 600 and welding alloys 182 and 82 were included in the search. The environments were NWC, 'partial' HWC and HWC

  17. Tensile properties of a nickel-base alloy subjected to surface severe plastic deformation

    International Nuclear Information System (INIS)

    A surface severe plastic deformation (S2PD) method has been applied to bulk specimens of HASTELLOY C-2000 alloy, a nickel-base alloy. The mechanical properties of the processed C-2000 alloy were determined via tensile tests and Vickers hardness measurements, whereas the microstructure was characterized using scanning electron microscopy, transmission electron microscopy, and X-ray diffractometry. The improved tensile strength was related to the nanostructure at the surface region, the residual compressive stresses, and the work-hardened surface layer, all of which resulted from the S2PD process. To understand the contributions of these three factors, finite element modeling was performed. It was found that the improved tensile strength could be interpreted based on the contributions of nano-grains, residual stresses, and work hardening

  18. Cobalt base alloy surfacing. Influence of welding process on residual stress level

    International Nuclear Information System (INIS)

    Influence of welding conditions on alloy characteristics for wear resistant valves, cocks and fittings of nuclear power plants is studied. Three welding methods: oxyacetylene torch (OAT), plasma arc welding (PAW) and gas tungsten arc welding (TIG) are tested for welding hard cobalt base alloy (stellite 6) on two substrates (304 L and A 37). Parameters investigated are preheating temperature for PAW and TIG, dilution for PAW and flame type for OAT. Microstructure is dendritic with a solid solution Co Cr W and an interdentritic eutectic (the hard part). Hardness is more or less dilution dependent and slightly temperature dependent for preheating. Residual stress is measured by X-ray diffraction but application of this method is sometimes difficult because of grain size or cobalt base alloy texture

  19. Design of lead-free candidate alloys for high-temperature soldering based on the Au–Sn system

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hattel, Jesper Henri; Hald, John

    2010-01-01

    Au–Sn based candidate alloys have been proposed as a substitute for high-lead content solders that are currently being used for high-temperature soldering. The changes in microstructure and microhardness associated with the alloying of Ag and Cu to the Au rich side as well to the Sn rich side of...... the Au–Sn binary system were explored in this work. Furthermore, the effects of thermal aging on the microstructure and microhardness of these promising Au–Sn based ternary alloys were investigated. For this purpose, the candidate alloys were aged at a lower temperature, 150°C for up to 1week and...

  20. Electron-phonon coupling in Ni-based binary alloys with application to displacement cascade modeling.

    Science.gov (United States)

    Samolyuk, G D; Béland, L K; Stocks, G M; Stoller, R E

    2016-05-01

    Energy transfer between lattice atoms and electrons is an important channel of energy dissipation during displacement cascade evolution in irradiated materials. On the assumption of small atomic displacements, the intensity of this transfer is controlled by the strength of electron-phonon (el-ph) coupling. The el-ph coupling in concentrated Ni-based alloys was calculated using electronic structure results obtained within the coherent potential approximation. It was found that Ni0.5Fe0.5, Ni0.5Co0.5 and Ni0.5Pd0.5 are ordered ferromagnetically, whereas Ni0.5Cr0.5 is nonmagnetic. Since the magnetism in these alloys has a Stoner-type origin, the magnetic ordering is accompanied by a decrease of electronic density of states at the Fermi level, which in turn reduces the el-ph coupling. Thus, the el-ph coupling values for all alloys are approximately 50% smaller in the magnetic state than for the same alloy in a nonmagnetic state. As the temperature increases, the calculated coupling initially increases. After passing the Curie temperature, the coupling decreases. The rate of decrease is controlled by the shape of the density of states above the Fermi level. Introducing a two-temperature model based on these parameters in 10 keV molecular dynamics cascade simulation increases defect production by 10-20% in the alloys under consideration. PMID:27033732

  1. Fabrication methods and applications of microstructured gallium based liquid metal alloys

    Science.gov (United States)

    Khondoker, M. A. H.; Sameoto, D.

    2016-09-01

    This review contains a comparative study of reported fabrication techniques of gallium based liquid metal alloys embedded in elastomers such as polydimethylsiloxane or other rubbers as well as the primary challenges associated with their use. The eutectic gallium–indium binary alloy (EGaIn) and gallium–indium–tin ternary alloy (galinstan) are the most common non-toxic liquid metals in use today. Due to their deformability, non-toxicity and superior electrical conductivity, these alloys have become very popular among researchers for flexible and reconfigurable electronics applications. All the available manufacturing techniques have been grouped into four major classes. Among them, casting by needle injection is the most widely used technique as it is capable of producing features as small as 150 nm width by high-pressure infiltration. One particular fabrication challenge with gallium based liquid metals is that an oxide skin is rapidly formed on the entire exposed surface. This oxide skin increases wettability on many surfaces, which is excellent for keeping patterned metal in position, but is a drawback in applications like reconfigurable circuits, where the position of liquid metal needs to be altered and controlled accurately. The major challenges involved in many applications of liquid metal alloys have also been discussed thoroughly in this article.

  2. Effect of boron addition on hydrogen embrittlement sensitivity in Fe-Ni based alloys

    International Nuclear Information System (INIS)

    In Fe-Ni based alloys, hydrogen embrittlement sensitivity is thought to correlate well with microstructure. The effect of boron addition on microstructure of Fe-Ni austenitic alloys has been investigated. It is found that 0.002 wt.% boron addition can significantly retard the formation of η phase, and only a few continuous carbides precipitate at the grain boundaries. As the boron content increases to 0.006 wt.%, carbides at grain boundaries become discontinuous, and are finer in size than that in the alloy with 0.002 wt.% boron. Significant decrease of the percent loss of reduction of area (RA) are seen in the alloys with boron contents lower than 0.006 wt.%. However, when further increasing the boron concentration to 0.01 wt.%, an increase in the percent loss of RA is found, due to the re-appearance of η phase and boride precipitation. Appropriate addition of boron can be an effective way of lowering hydrogen embrittlement sensitivity in Fe-Ni based alloys.

  3. Electron–phonon coupling in Ni-based binary alloys with application to displacement cascade modeling

    International Nuclear Information System (INIS)

    Energy transfer between lattice atoms and electrons is an important channel of energy dissipation during displacement cascade evolution in irradiated materials. On the assumption of small atomic displacements, the intensity of this transfer is controlled by the strength of electron–phonon (el–ph) coupling. The el–ph coupling in concentrated Ni-based alloys was calculated using electronic structure results obtained within the coherent potential approximation. It was found that Ni0.5Fe0.5, Ni0.5Co0.5 and Ni0.5Pd0.5 are ordered ferromagnetically, whereas Ni0.5Cr0.5 is nonmagnetic. Since the magnetism in these alloys has a Stoner-type origin, the magnetic ordering is accompanied by a decrease of electronic density of states at the Fermi level, which in turn reduces the el–ph coupling. Thus, the el–ph coupling values for all alloys are approximately 50% smaller in the magnetic state than for the same alloy in a nonmagnetic state. As the temperature increases, the calculated coupling initially increases. After passing the Curie temperature, the coupling decreases. The rate of decrease is controlled by the shape of the density of states above the Fermi level. Introducing a two-temperature model based on these parameters in 10 keV molecular dynamics cascade simulation increases defect production by 10–20% in the alloys under consideration. (paper)

  4. Neutronics Evaluation of Lithium-Based Ternary Alloys in IFE Blankets

    Energy Technology Data Exchange (ETDEWEB)

    Jolodosky, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fratoni, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-11-20

    Pre-conceptual fusion blanket designs require research and development to reflect important proposed changes in the design of essential systems, and the new challenges they impose on related fuel cycle systems. One attractive feature of using liquid lithium as the breeder and coolant is that it has very high tritium solubility and results in very low levels of tritium permeation throughout the facility infrastructure. However, lithium metal vigorously reacts with air and water and presents plant safety concerns. If the chemical reactivity of lithium could be overcome, the result would have a profound impact on fusion energy and associated safety basis. The overriding goal of this project is to develop a lithium-based alloy that maintains beneficial properties of lithium (e.g. high tritium breeding and solubility) while reducing overall flammability concerns. To minimize the number of alloy combinations that must be explored, only those alloys that meet certain nuclear performance metrics will be considered for subsequent thermodynamic study. The specific scope of this study is to evaluate the neutronics performance of lithium-based alloys in the blanket of an inertial confinement fusion (ICF) engine. The results of this study will inform the development of lithium alloys that would guarantee acceptable neutronics performance while mitigating the chemical reactivity issues of pure lithium.

  5. Cerium-Based, Intermetallic-Strengthened Aluminum Casting Alloy: High-Volume Co-product Development

    Science.gov (United States)

    Sims, Zachary C.; Weiss, D.; McCall, S. K.; McGuire, M. A.; Ott, R. T.; Geer, Tom; Rios, Orlando; Turchi, P. A. E.

    2016-07-01

    Several rare earth elements are considered by-products to rare earth mining efforts. By using one of these by-product elements in a high-volume application such as aluminum casting alloys, the supply of more valuable rare earths can be globally stabilized. Stabilizing the global rare earth market will decrease the long-term criticality of other rare earth elements. The low demand for Ce, the most abundant rare earth, contributes to the instability of rare earth extraction. In this article, we discuss a series of intermetallic-strengthened Al alloys that exhibit the potential for new high-volume use of Ce. The castability, structure, and mechanical properties of binary, ternary, and quaternary Al-Ce based alloys are discussed. We have determined Al-Ce based alloys to be highly castable across a broad range of compositions. Nanoscale intermetallics dominate the microstructure and are the theorized source of the high ductility. In addition, room-temperature physical properties appear to be competitive with existing aluminum alloys with extended high-temperature stability of the nanostructured intermetallic.

  6. Electron–phonon coupling in Ni-based binary alloys with application to displacement cascade modeling

    Science.gov (United States)

    Samolyuk, G. D.; Béland, L. K.; Stocks, G. M.; Stoller, R. E.

    2016-05-01

    Energy transfer between lattice atoms and electrons is an important channel of energy dissipation during displacement cascade evolution in irradiated materials. On the assumption of small atomic displacements, the intensity of this transfer is controlled by the strength of electron–phonon (el–ph) coupling. The el–ph coupling in concentrated Ni-based alloys was calculated using electronic structure results obtained within the coherent potential approximation. It was found that Ni0.5Fe0.5, Ni0.5Co0.5 and Ni0.5Pd0.5 are ordered ferromagnetically, whereas Ni0.5Cr0.5 is nonmagnetic. Since the magnetism in these alloys has a Stoner-type origin, the magnetic ordering is accompanied by a decrease of electronic density of states at the Fermi level, which in turn reduces the el–ph coupling. Thus, the el–ph coupling values for all alloys are approximately 50% smaller in the magnetic state than for the same alloy in a nonmagnetic state. As the temperature increases, the calculated coupling initially increases. After passing the Curie temperature, the coupling decreases. The rate of decrease is controlled by the shape of the density of states above the Fermi level. Introducing a two-temperature model based on these parameters in 10 keV molecular dynamics cascade simulation increases defect production by 10–20% in the alloys under consideration.

  7. Evaluation of Ni-Cr-base alloys for SOFC interconnect applications

    Science.gov (United States)

    Yang, Zhenguo; Xia, Guan-Guang; Stevenson, Jeffry W.

    To further understand the suitability of Ni-Cr-base alloys for solid oxide fuel cell (SOFC) interconnect applications, three commercial Ni-Cr-base alloys, Haynes 230, Hastelloy S and Haynes 242 were selected and evaluated for oxidation behavior under different exposure conditions, scale conductivity and thermal expansion. Haynes 230 and Hastelloy S, which have a relatively high Cr content, formed a thin scale mainly comprised of Cr 2O 3 and (Mn,Cr,Ni) 3O 4 spinels under SOFC operating conditions, demonstrating excellent oxidation resistance and a high scale electrical conductivity. In contrast, a thick double-layer scale with a NiO outer layer above a chromia-rich substrate was grown on Haynes 242 in moist air or at the air side of dual exposure samples, indicating limited oxidation resistance for the interconnect application. With a face-centered-cubic (FCC) substrate, all three alloys possess a coefficient of thermal expansion (CTE) that is higher than that of candidate ferritic stainless steels, e.g. Crofer22 APU. Among the three alloys, Haynes 242, which is heavily alloyed with W and Mo and contains a low Cr content, demonstrated the lowest average CTE at 13.1 × 10 -6 K -1 from room temperature to 800 °C, but it was also observed that the CTE behavior of Haynes 242 was very non-linear.

  8. Antimony Resistance in Leishmania, Focusing on Experimental Research

    Directory of Open Access Journals (Sweden)

    Fakhri Jeddi

    2011-01-01

    Full Text Available Leishmaniases are parasitic diseases that spread in many countries with a prevalence of 12 million cases. There are few available treatments and antimonials are still of major importance in the therapeutic strategies used in most endemic regions. However, resistance toward these compounds has recently emerged in areas where the replacement of these drugs is mainly limited by the cost of alternative molecules. In this paper, we reviewed the studies carried out on antimonial resistance in Leishmania. Several common limitations of these works are presented before prevalent approaches to evidence antimonial resistance are related. Afterwards, phenotypic determination of resistance is described, then confronted to clinical outcome. Finally, we detail molecular mechanisms and targets involved in resistance and already identified in vitro within selected mutant strains or in clinical isolates.

  9. Gilbert damping and anisotropic magnetoresistance in iron-based alloys

    Science.gov (United States)

    Berger, L.

    2016-07-01

    We use the two-current model of Campbell and Fert to understand the compositional dependence of the Gilbert damping parameter in certain iron alloys. In that model, spin-up and spin-down carriers have different resistivities ρ↑ and ρ↓. We emphasize the part of the Gilbert parameter, called Gsf, generated by spin-flip interband processes. Both Gsf and the anisotropic magnetoresistance Δρ are proportional to the square of the spin-orbit parameter, and also proportional to ρ↑. In bcc alloys of iron with V, Cr, Mo, etc. solutes on the left of iron in the periodic table, ρ↑ is increased by a scattering resonance (Gomes and Campbell, 1966, 1968). Then ρ↑, Δρ, and Gsf all exhibit a peak at the same moderate concentration of the solute. We find the best fit between this theory and existing experimental data of Gilbert damping for Fe-V epitaxial films at room temperature (Cheng, 2006; Scheck et al., 2007). At room temperature, the predicted Gsf peak is masked by a background arising from non-flip intraband processes. At elevated temperatures, the peak is expected to become more prominent, and less hidden in the background.

  10. Creep rupture testing of alloy 617 and A508/533 base metals and weldments.

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.; Li, M.; Soppet, W.K.; Rink, D.L. (Nuclear Engineering Division)

    2012-01-17

    The NGNP, which is an advanced HTGR concept with emphasis on both electricity and hydrogen production, involves helium as the coolant and a closed-cycle gas turbine for power generation with a core outlet/gas turbine inlet temperature of 750-1000 C. Alloy 617 is a prime candidate for VHTR structural components such as reactor internals, piping, and heat exchangers in view of its resistance to oxidation and elevated temperature strength. However, lack of adequate data on the performance of the alloy in welded condition prompted to initiate a creep test program at Argonne National Laboratory. In addition, Testing has been initiated to evaluate the creep rupture properties of the pressure vessel steel A508/533 in air and in helium environments. The program, which began in December 2009, was certified for quality assurance NQA-1 requirements during January and February 2010. Specimens were designed and fabricated during March and the tests were initiated in April 2010. During the past year, several creep tests were conducted in air on Alloy 617 base metal and weldment specimens at temperatures of 750, 850, and 950 C. Idaho National Laboratory, using gas tungsten arc welding method with Alloy 617 weld wire, fabricated the weldment specimens. Eight tests were conducted on Alloy 617 base metal specimens and nine were on Alloy 617 weldments. The creep rupture times for the base alloy and weldment tests were up to {approx}3900 and {approx}4500 h, respectively. The results showed that the creep rupture lives of weld specimens are much longer than those for the base alloy, when tested under identical test conditions. The test results also showed that the creep strain at fracture is in the range of 7-18% for weldment samples and were much lower than those for the base alloy, under similar test conditions. In general, the weldment specimens showed more of a flat or constant creep rate region than the base metal specimens. The base alloy and the weldment exhibited tertiary creep

  11. Nickel based alloys compatibility with fuel salts for molten salt reactor with thorium and uranium support

    International Nuclear Information System (INIS)

    R and D on molten salt reactors (MSR) in Europe are concentrated now on fast/intermediate spectrum concepts which were recognised as long-term alternative to solid fuelled fast reactors due to their attractive features: strong negative feedback coefficients, easy in-service inspection, and simplified fuel cycle. For high-temperature MSR corrosion of the metallic container alloy in primary circuit is the primary concern. Key problem receiving current attention include surface fissures in Ni-based alloys probably arising from fission product tellurium attack. This paper summarises results of corrosion tests conducted recently to study effect of oxidation state in selected fuel salts on tellurium attack and to develop means of controlling tellurium cracking in the special Ni - based alloys recently developed for large power units: molten salt actinide recycler and transmuter (MOSART) and molten salt fast reactor (MSFR). Tellurium corrosion of Ni-based alloys was tested in the temperature range from 730 deg. C up to 800 deg. C in stressed and unloaded conditions with fuel LiF-BeF2-UF4 and LiF-BeF2-ThF4-UF4 salt mixtures at different [U(IV)]/[U(III)] ratios from 0.7 up to 500. Following Russian and French Ni-based alloys (in mass%): HN80M-VI (Mo-12, Cr-7.6, Nb-1.5), HN80MTY (Mo-13, Cr-6.8, Al-1.1, Ti-0.9), HN80MTW (Mo-9.4, Cr-7.0, Ti-1.7, W-5.5) and EM-721 (W-25.2, Cr-5.7, Ti-0.17) were used for the study in the corrosion facility. The HN80MTY alloy has shown the best resistance against Te cracking and after test mechanical properties. (authors)

  12. Synthesis and characterization of a novel mesoporous silica funtionalized whith [1,5 bis (di-2-pyridyl) methylene thiocarbohydrazide] and its application as enrichment sorbent for determination of antimony by FI-HG-ETAAS

    OpenAIRE

    Siles Cordero, María Teresa; López Guerrero, María del Mar; Vereda Alonso, Elisa Isabel; García de Torres, Amparo; Cano Pavón, José Manuel

    2014-01-01

    Antimony is an element of environmental concern due to its toxicity and biological effects and is therefore considered as a priority pollutant by the US Environmental Protection Agency (EPA). Dissolved antimony is present in seawater at very low concentration levels, typical concentrations of Sb in unpolluted water samples are less than 1 µg L-1. Since the concentration of this element in water is very low, high sensitive analytical techniques are required, The system is based on retent...

  13. Quaternary alloys based on II-VI semiconductors

    CERN Document Server

    Tomashyk, Vasyl

    2014-01-01

    Systems Based on ZnSSystems Based on ZnSeSystems Based on ZnTeSystems Based on CdSSystems Based on CdSeSystems Based on CdTeSystems Based on HgSSystems Based on HgSeSystems Based on HgTeIndexReferences appear at the end of each chapter.

  14. Ternary alloys based on II-VI semiconductor compounds

    CERN Document Server

    Tomashyk, Vasyl; Shcherbak, Larysa

    2013-01-01

    Phase Equilibria in the Systems Based on ZnSSystems Based on ZnSeSystems Based on ZnTeSystems Based on CdSSystem Based on CdSeSystem Based on CdTeSystems Based on HgSSystems Based on HgSeSystems Based on HgTeIndexReferences appear at the end of each chapter.

  15. The influence of thermomechanical treatment on structure of FeAl intermetallic phase-based alloys

    Directory of Open Access Journals (Sweden)

    I. Bednarczyk

    2008-08-01

    Full Text Available Purpose: The major problem restricting universal employment of intermetallic phase base alloy is their low plasticity which leads to hampering their development as construction materials. The following work concentrates on the analysis of microstructure and plasticity of ordered FeAl (B2 alloy during cold and hot deformation and rolling process.Design/methodology/approach: After casting and annealing, alloy specimens were subjected to axial-symmetric compression in the Gleeble 3800 simulator at temperatures ranging from 800, 900 and 1000°C at 0.1s-1 strain rate. In order to analyse the processes which take place during deformation, the specimens after deformation were intensely cooled with water. The process was conducted on the K -350 quarto rolling mill used for hot rolling of flat products. The process was conducted in some stages at temperature ranging from 1200-1000°C: Structural examination was carried out using light microscopy. The examination of the substructure was carried out by transmission electron microscopy (TEM.Findings: The research carried out enabled the understanding of the phenomena taking place during hot rolling of the investigated alloy. which has been also confirmed in plastometric studies conducted in the form of hot compression tests. The microstructure analyses applying optic and electron microscopy have revealed the structure reconstruction processes occurring in FeAl alloys during cold and hot deformation.Practical implications: The research carried out enabled the understanding of the phenomena taking place during deformation and annealing of the investigated alloy. The obtained sheets can be used as constructional elements working in complex stress fields, at a high temperature and corrosive environments. The results will constitute the basis for modelling the structural changes.Originality/value: The obtained results are vital for designing an effective thermo - mechanical processing technology for the

  16. Magnetic properties of two new uranium-based alloys: UAuCu4 and UPdCu4

    International Nuclear Information System (INIS)

    Two new uranium-based alloys UAuCu4 and UPdCu4 have been prepared and their magnetic properties studied. The NMR of the isotope 63Cu in these alloys suggests that they are well ordered ternary materials. There is a strong correlation between the occupancy of the (4c) sites in the structure and the relative size of the two non-uranium atoms in these alloys. (author)

  17. Lattice dynamics of femtosecond laser-excited antimony

    Science.gov (United States)

    Abdel-Fattah, Mahmoud Hanafy; Bugayev, Aleksey; Elsayed-Ali, Hani E.

    2016-07-01

    Ultrafast electron diffraction is used to probe the lattice dynamics of femtosecond laser-excited antimony thin film. The temporal hierarchies of the intensity and position of diffraction orders are monitored. The femtosecond laser excitation of antimony film was found to lead to initial compression after the laser pulse, which gives way to tension vibrating at new equilibrium displacement. A damped harmonic oscillator model, in which the hot electron-blast force contributes to the driving force of oscillations in lattice spacing, is used to interpret the data. The electron-phonon energy-exchange rate and the electronic Grüneisen parameter were obtained.

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

    International Nuclear Information System (INIS)

    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)

  19. Superconducting state parameters of indium-based binary alloys

    Indian Academy of Sciences (India)

    A M Vora; Minal H Patel; P N Gajjar; A R Jani

    2002-05-01

    Our well-recognized pseudopotential is used to investigate the superconducting state parameters viz; electron–phonon coupling strength , Coulomb pseudopotentialµ *, transition temperature c, isotope effective exponent and interaction strength 0 for the In1-Zn and In1-Sn binary alloys. We have incorporated six different types of local field correction functions, proposed by Hartree, Taylor, Vashistha–Singwi, Ichimaru–Utsumi, Farid et al and Sarkar et al to show the effect of exchange and correlation on the aforesaid properties. Very strong influence of the various exchange and correlation functions is concluded from the present study. The comparison with other such theoretical values is encouraging, which confirms the applicability of our model potential in explaining the superconducting state parameters of binary mixture.

  20. Characterization of hydrogen barrier coatings for titanium-base alloys

    International Nuclear Information System (INIS)

    The purpose of this study was to investigate the barrier efficiency of a thick thermal spray deposit on the α-titanium alloy, Ti-5Al-2.4Sn against hydrogen penetration. Therefore, a duplex coating has been applied by plasma spraying using a Sulzer Metco F4 gun. The selected duplex coating system consisted of a 0.1-0.2 mm thick tantalum bond layer and a chromium oxide top layer doped with 3 wt% titanium oxide. The achieved thickness of the top layer was about 0.6 mm. The coated specimens have been characterized with regard to bond strength, hardness and microstructure. Hydrogen charging experiments were performed in a Sievert's apparatus

  1. Development of GaInNAsSb alloys: Growth, band structure, optical properties and applications

    International Nuclear Information System (INIS)

    In the past few years, GaInNAsSb has been found to be a potentially superior material to both GaInNAs and InGaAsP for communications wavelength laser applications. It has been observed that due to the surfactant role of antimony during epitaxy, higher quality material can be grown over the entire 1.2-1.6 μm range on GaAs substrates. In addition, it has been discovered that antimony in GaInNAsSb also works as a constituent that significantly modifies the valence band. These findings motivated a systematic study of GaInNAsSb alloys with widely varying compositions. Our recent progress in growth and materials development of GaInNAsSb alloys and our fabrication of 1.5-1.6 μm lasers are discussed in this paper. We review our recent studies of the conduction band offset in (Ga,In) (N,As,Sb)/GaAs quantum wells and discuss the growth challenges of GaInNAsSb alloys. Finally, we report record setting long wavelength edge emitting lasers and the first monolithic VCSELs operating at 1.5 μm based on GaInNAsSb QWs grown on GaAs. Successful development of GaInNAsSb alloys for lasers has led to a much broader range of potential applications for this material including: solar cells, electroabsorption modulators, saturable absorbers and far infrared optoelectronic devices and these are also briefly discussed in this paper. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Experimental and Theoretical Investigation of Three Alloy 690 Mockup Components: Base Metal and Welding Induced Changes

    Directory of Open Access Journals (Sweden)

    Rickard R. Shen

    2014-01-01

    Full Text Available The stress corrosion cracking (SCC resistance of cold deformed thermally treated (TT Alloy 690 has been questioned in recent years. As a step towards understanding its relevancy for weld deformed Alloy 690 in operating plants, Alloy 690 base metal and heat affected zone (HAZ microstructures of three mockup components have been studied. All mockups were manufactured using commercial heats and welding procedures in order to attain results relevant to the materials in the field. Thermodynamic calculations were performed to add confidence in phase identification as well as understanding of the evolution of the microstructure with temperature. Ti(C,N banding was found in all materials. Bands with few large Ti(C,N precipitates had negligible effect on the microstructure, whereas bands consisting of numerous small precipitates were associated with locally finer grains and coarser M23C6 grain boundary carbides. The Ti(C,N remained unaffected in the HAZ while the M23C6 carbides were fully dissolved close to the fusion line. Cold deformed solution annealed Alloy 690 is believed to be a better representation of this region than cold deformed TT Alloy 690.

  3. Strengthening of Mg based alloy through grain refinement for orthopaedic application.

    Science.gov (United States)

    Nayak, Soumyaranjan; Bhushan, Bharat; Jayaganthan, R; Gopinath, P; Agarwal, R D; Lahiri, Debrupa

    2016-06-01

    Magnesium is presently attracting a lot of interest as a replacement to clinically used orthopaedic implant materials, due to its ability to solve the stress shielding problems, biodegradability and osteocompatibility. However, the strength of Mg is still lower than the requirement and it becomes worse after it starts degrading fast, while being exposed in living body environment. This research explores the effectiveness of 'grain refinement through deformation', as a tool to modify the strength (while keeping elastic modulus unaffected) of Mg based alloys in orthopaedic application. Hot rolled Mg-3wt% Zn alloy (MZ3) has been investigated for its potential in orthopaedic implant. Microstructure, mechanical properties, bio-corrosion properties and biocompatibility of the rolled samples are probed into. Grain size gets refined significantly with increasing amount of deformation. The alloy experiences a marked improvement in hardness, yield strength, ultimate tensile strength, strain and toughness with finer grain size. An increment in accelerated corrosion rate is noted with decreasing grain size, which is correlated to the increased grain boundary area and mechano-chemical dissolution. However, immersion test in simulated body fluid (SBF) reveals reduction in corrosion rate after third day of immersion. This was possible owing to precipitation of protective hydroxyapatite (HA) layer, formed out of the interaction of SBF and the alloy. More nucleation sites at the grain boundary for fine grained samples help in forming more HA and thus reduce the corrosion rate. Human osteosarcoma cells show less viability and adhesion on grain refined alloy. PMID:26745721

  4. 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.

  5. New high strength technologically ecological and expedient economically advantageous alloys on Fe-C base

    International Nuclear Information System (INIS)

    The paper presents framework a part of by now obtained results of the authors studies in the period 1967(68) - 2002 about possibilities for obtaining new high-strength and wear resistant cast alloys on, Fe-C base (complex alloyed steels and cast irons of different systems with different structure, reflected in over 125 articles, 15 inventions (patents) and other scientific studies. The paper includes summarized results and discussion. Key words: new austenite steels and cast irons, mechanical characteristics, wear resistance. (Original)

  6. An X-ray diffraction study of defect parameters in a Ti-base alloy

    Indian Academy of Sciences (India)

    G Karmaker; P Mukherjee; A K Meikap; S K Chattopadhyay; S K Chatterjee

    2001-12-01

    Detailed studies based on the well established method of Fourier line shape analysis have been made on the X-ray diffraction profile of hexagonal titanium alloy of nominal composition Ti–6.58% Al–3.16% Mo–1.81% Zr–0.08% Fe–0.012% N–0.0078% C. While deformation fault probability, , has been found to be quite high compared to that of pure titanium, the deformation growth fault parameter, , shows a negative value ruling out the presence of growth fault in this alloy in the deformed state.

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

    International Nuclear Information System (INIS)

    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

  8. Chemical durability and degradation mechanisms of HT9 based alloy waste forms with variable Zr content

    Energy Technology Data Exchange (ETDEWEB)

    Olson, L. N. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-30

    In Corrosion studies were undertaken on alloy waste forms that can result from advanced electrometallurgical processing techniques to better classify their durability and degradation mechanisms. The waste forms were based on the RAW3-(URe) composition, consisting primarily of HT9 steel and other elemental additions to simulate nuclear fuel reprocessing byproducts. The solution conditions of the corrosion studies were taken from an electrochemical testing protocol, and meant to simulate conditions in a repository. The alloys durability was examined in alkaline and acidic brines.

  9. Effect of TBC on oxidation behaviour of γ-TiAl based alloy

    OpenAIRE

    G. Moskal

    2007-01-01

    Purpose: The purpose of the research was identification of the influence of TBC coating system on oxidation resistance of TiAl based alloy during oxidation at temperature of 900°C and 950°C for 500h and 200h respectively.Design/methodology/approach: The APS technique was used to modify and improvement of oxidation resistance of TiAl intermetallic alloy. As a bond coat the NiCrAlY overlay coating was applied. The bond-coat provided a good bonding strength between matrix and ceramic top coat. T...

  10. Effect of cold work on initiation stage crack growth rate of nickel based alloys

    International Nuclear Information System (INIS)

    To investigate the effect of cold work on initiation stage crack growth rates of nickel based alloy, initiation stage crack growth rates were measured for simulated PWR primary water conditions using flat type specimens which were prepared from three different heats of alloy 600 and then 20 and 40% cold worked. Almost all data showed the stress had an increasing linear dependency on crack growth rate ; however there was some scattering of data and some materials showed a different tendency. Since yield strength was increased by cold work, for the same stress, the initiation stage crack growth rates were restrained or were not changed significantly by cold work. (author)

  11. Integrated Design and Rapid Development of Refractory Metal Based Alloys for Fossil Energy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Dogan, O.N.; King, P.E.; Gao, M.C.

    2008-07-01

    One common barrier in the development of new technologies for future energy generating systems is insufficiency of existing materials at high temperatures (>1150oC) and aggressive atmospheres (e.g., steam, oxygen, CO2). To overcome this barrier, integrated design methodology will be applied to the development of refractory metal based alloys. The integrated design utilizes the multi-scale computational methods to design materials for requirements of processing and performance. This report summarizes the integrated design approach to the alloy development and project accomplishments in FY 2008.

  12. Electronic aspects of the martensitic transition in Ni-Mn based Heusler alloys

    International Nuclear Information System (INIS)

    The martensitic transformation temperature Ms depends linearly on the valence electron concentration for Ni-Mn-X Heusler systems where X is a group III-group V element. However, the slopes of the linearity are different for alloys with different X species and increases either as X changes from Al to In (isoelectronic) or from In to Sb (increase in number of p electrons). We discuss the features in the Ms vs e/a diagram and the relative stability of the various crystallographic phases of Ni-Mn based Heusler alloys

  13. Structural and mechanical characteristics of some lead-free Cu-Sn based solder alloys

    OpenAIRE

    Mitovski Aleksandra M.; Balanović Ljubiša T.; Živković Dragana T.; Marjanović Šaša R.; Marjanović Bata R.; Novaković Slađana O.

    2008-01-01

    The results of structural and mechanical characteristics of lead-free Cu-Sn based solder alloys, produced in Company "11. mart" AD Srebrenica (Republic of Srpska), are presented in this paper. The results of investigation of samples - alloys CuSnl4, CuSnlFelAlO.5, CuSnlOFelAllMnO.5 and CuA110Fe3Mn produced by different processing methods, include the data obtained by optical microscopy and measurements of hardness, micro hardness and electroconductivity, in order to characterize mentioned all...

  14. Niobium-aluminum base alloys having improved, high temperature oxidation resistance

    Science.gov (United States)

    Hebsur, Mohan G. (Inventor); Stephens, Joseph R. (Inventor)

    1991-01-01

    A niobium-aluminum base alloy having improved oxidation resistance at high temperatures and consisting essentially of 48%-52% niobium, 36%-42% aluminum, 4%-10% chromium, 0%-2%, more preferably 1%-2%, silicon and/or tungsten with tungsten being preferred, and 0.1%-2.0% of a rare earth selected from the group consisting of yttrium, ytterbium and erbium. Parabolic oxidation rates, k.sub.p, at 1200.degree. C. range from about 0.006 to 0.032 (mg/cm.sup.2).sup.2 /hr. The new alloys also exhibit excellent cyclic oxidation resistance.

  15. Electrochemical machining of hard tungsten carbide base alloys in neutral solutions using anodal pulses imposition

    Energy Technology Data Exchange (ETDEWEB)

    Davydov, A.D.; Klepikov, R.P.; Moroz, I.I.

    1981-01-01

    The experiments carried out show that activating pulses of higher amplitude imposition on constant comparatively low voltage extends the possibility of anodic dissolution process control. It proves to be possible to select pulse and constant voltage parameters, allowing to decrease the passivation effect and conduct the process of electrochemical machining of hard tungsten carbide base alloys in neutral water solutions.

  16. Electrochemical machining of hard tungsten carbide base alloys in neutral solutions using anodal pulses imposition

    International Nuclear Information System (INIS)

    The experiments carried out show that activating pulses of higher amplitude imposition on constant comparatively low voltage extends the possibility of anodic dissolution process control. It proves to be possible to select pulse and constant voltage parameters, allowing to decrease the passivation effect and conduct the process of electrochemical machining of hard tungsten carbide base alloys in neutral water solutions

  17. Property enhancement of orthorhombic Ti2AlNb-based intermetallic alloys

    International Nuclear Information System (INIS)

    This paper provides an overview of our research efforts aimed at improving the room and high temperature mechanical properties of an orthorhombic Ti2AlNb-based Ti-22Al-27Nb intermetallic alloy by the microstructural and compositional modifications, and the dispersion of fine TiB particulates. Challenges in each of the activities is highlighted and discussed. (orig.)

  18. Heterogeneous Nb-Based Nuclei for the Grain Refinement of Al-Si Alloys

    Science.gov (United States)

    Bolzoni, L.; Hari Babu, N.

    2016-05-01

    Nb-based intermetallics are, generally, low-density high-temperature materials used for structural applications or cryogenic superconductors. In this work, we report the development of an Al(96)-Nb(2)-B(2) master alloy where in situ-formed micrometric Nb-based intermetallics (i.e. NbB2 and Al3Nb) are used for a completely different purpose: to promote the refinement of Al-Si alloys by taking advantage of enhanced heterogeneous nucleation. Nb-based intermetallics have the right characteristics, like low density, stability at high temperature and good lattice match, to be used as heterogeneous nucleation substrates. It was found that the addition of these Nb-based intermetallics permits the significant refinement of the microstructural features of the Al-Si alloy studied. The enhanced heterogeneous nucleation makes the grain size of the material far less dependent on the cooling rate, which is one of the critical parameters influencing the variation of the properties of the alloy.

  19. A distributed optical fiber sensor for hydrogen detection based on Pd, and Mg alloys

    NARCIS (Netherlands)

    Perrotton, C.; Slaman, M.; Javahiraly, N.; Schreuders, H.; Dam, B.; Meyrueis, P.

    2010-01-01

    An optical fiber containing structured hydrogen sensing points, consisting of Palladium and/or Magnesium alloys is proposed and characterized. The sensitive layer is deposited on the outside of a multimode fiber, after removing the optical cladding. The sensor is based on a measurement technique whi

  20. Corrosion properties of plasma deposited nickel and nickel-based alloys

    Czech Academy of Sciences Publication Activity Database

    Voleník, Karel; Pražák, M.; Kalabisová, E.; Kreislová, K.; Had, J.; Neufuss, Karel

    2003-01-01

    Roč. 48, č. 3 (2003), s. 215-226. ISSN 0001-7043 R&D Projects: GA ČR GA106/99/0298 Institutional research plan: CEZ:AV0Z2043910 Keywords : plasma deposits, nickel , nickel -based alloys Subject RIV: JK - Corrosion ; Surface Treatment of Materials

  1. Magnetic damping constant in Co-based full heusler alloy epitaxial films

    International Nuclear Information System (INIS)

    Co-based full-Heusler alloys, such as Co2MnSi and Co2MnGe, are expected to be used as half-metallic ferromagnetic material, which has complete spin polarization. They are the most promising materials for realizing half-metallicity at room temperature due to their high Curie temperature. The optimization of the magnetic damping constant of ferromagnetic materials is extremely important for achieving high-speed magnetization switching and reducing critical current density for spin torque transfer switching. We have systematically investigated the magnetic damping constant in Co-based full Heusler alloy epitaxial films. We found that the Gilbert damping constant seems to be roughly proportional to the total density of states at the Fermi level (EF) by first principle calculation. A very small magnetic damping constant of 0.003 in the Co2Fe0.4Mn0.6Si epitaxial film was demonstrated. The small magnetic damping constant in Co2FexMn1−xSi films with x < 0.6 can be attributed to the half-metallicity of Heusler alloys. Co-based full Heusler alloys with both half-metallicity and small magnetic damping will be very useful for future applications based on spintronic devices. (paper)

  2. Hard recharging. Metallurgical characteristics and use properties of hard recharging deposited by based cobalt alloys melting

    International Nuclear Information System (INIS)

    Hard recharging with cobalt base alloys are used in different parts of nuclear power plants. This paper presents mechanical properties, wear, thermal shock and corrosion resistances of hard coatings according to RCC-M S8000 rules, and explains relations between code recommendations and uses characteristics. (A.B.). 9 figs., 4 tabs

  3. Corrosion behaviour, microstructure and phase transitions of Zn-based alloys

    Indian Academy of Sciences (India)

    A K Yildiz; M Kaplan

    2004-08-01

    This paper is aimed at investigating the corrosion behaviour, microstructure and phase transitions of Zn-based alloys with different compositions. The corrosion tests are carried out both in acidic medium using 1 N HCl solution and in temperature dependence of thermogravimetric analysis (TGA). In the two different media, in particular, the corrosion behaviour of Zn-based alloys with respect to Al and Si contents is examined, and microstructure in acidic and TGA and phase transformations in TGA are also studied. Corrosion mechanism in TGA is also examined in terms of oxidation parameters and activation energies. The study reveals that corrosion behaviour of Zn-based alloys in acidic medium shows sometimes an increase and sometimes a decrease with time due to Al content which assists in delaying the corrosion by forming a oxide layer on the surface of Zn-based alloys. This property does not appear in temperature dependence of TGA. Further, Si content appears to remain in main matrix without being affected by acidic solution. On the other hand, it is observed that in microstructure, AlO(Al2O3), ZnO oxides and Zn–Cu phase precipitations are formed in main matrix, grain boundaries and partially inside the grains.

  4. The analysis of Al-based alloys by calorimetry: quantitative analysis of reactions and reaction kinetics

    OpenAIRE

    Starink, M.J.

    2004-01-01

    Differential scanning calorimetry (DSC) and isothermal calorimetry have been applied extensively to the analysis of light metals, especially Al based alloys. Isothermal calorimetry and differential scanning calorimetry are used for analysis of solid state reactions, such as precipitation, homogenisation, devitrivication and recrystallisation; and solid–liquid reactions, such as incipient melting and solidification, are studied by differential scanning calorimetry. In producing repeatable calo...

  5. ZnO-based semiconductors studied by Raman spectroscopy. Semimagnetic alloying, doping, and nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Schumm, Marcel

    2009-07-01

    ZnO-based semiconductors were studied by Raman spectroscopy and complementary methods (e.g. XRD, EPS) with focus on semimagnetic alloying with transition metal ions, doping (especially p-type doping with nitrogen as acceptor), and nanostructures (especially wet-chemically synthesized nanoparticles). (orig.)

  6. Application of feal intermetallic phase matrix based alloys in the turbine components of a turbocharger

    Directory of Open Access Journals (Sweden)

    J. Cebulski

    2015-01-01

    Full Text Available This paper presents a possible application of the state-of-the-art alloys based on the FeAl intermetallic phases as materials for the manufacture of heat-proof turbine components in an automobile turbocharger. The research was aimed at determining the resistance to corrosion of Fe40Al5CrTiB alloy in a gaseous environment containing 9 % O2 + 0,2 % HCl + 0,08 % SO2 + N2. First the kinetics of corrosion processes for the considered alloy were determined at the temperatures of 900 °C, 1 000 °C and 1 100 °C, which was followed by validation under operating conditions. To do so, the tests were carried out over a distance of 20 000 km. The last stage involved examination of the surfaces after the test drive. The obtained results are the basis for further research in this field.

  7. The Degradation Interface of Magnesium Based Alloys in Direct Contact with Human Primary Osteoblast Cells.

    Directory of Open Access Journals (Sweden)

    Nezha Ahmad Agha

    Full Text Available Magnesium alloys have been identified as a new generation material of orthopaedic implants. In vitro setups mimicking physiological conditions are promising for material / degradation analysis prior to in vivo studies however the direct influence of cell on the degradation mechanism has never been investigated. For the first time, the direct, active, influence of human primary osteoblasts on magnesium-based materials (pure magnesium, Mg-2Ag and Mg-10Gd alloys is studied for up to 14 days. Several parameters such as composition of the degradation interface (directly beneath the cells are analysed with a scanning electron microscope equipped with energy dispersive X-ray and focused ion beam. Furthermore, influence of the materials on cell metabolism is examined via different parameters like active mineralisation process. The results are highlighting the influences of the selected alloying element on the initial cells metabolic activity.

  8. EFFECT OF TESTING ENVIRONMENT ON FRACTURING BEHAVIOR OF Fe3Si BASED ALLOY

    Institute of Scientific and Technical Information of China (English)

    J.H. Peng; G.L. Chen

    2003-01-01

    The mechanical behavior of Fe3Si based alloy with B2 structure was studied by tensionand fracture toughness test in various testing media. The fracture strength σb ofFe3Si alloy decreased in the following order: oxygen, air and hydrogen respectively.The fracture toughness in different testing environment showed that KiC in oxygenis 11.5±0.3MPa. m1/2, and is 8.6±0.4MPa. m1/2 in distilled water. The reductionof fracture toughness is contributed to the environmental reaction of Si with water.Addition of Al element in Fe3Si is not beneficial to improve the intrinsic ductility ofFe-14Si-3Al alloy. The scattering phenomenon of fracture strength was found, andexplained by fracture mechanics. It was found by means of SEM that the fracture modechanged from transgranular in oxygen to intergranular in hydrogen gas and distilledwater.

  9. Thermodynamics of several lewis-acid-base stabilized transition metal alloys

    Science.gov (United States)

    Gibson, John K.; Brewer, Leo; Gingerich, Karl A.

    1984-11-01

    High-temperature (1425 to 2750 K) thermodynamic activities of one or both components of twenty-five binary alloys of a group IVB-VIB element (Ti, Zr, Hf, Nb, Ta, or W) with a platinum group element (Ru, Os, Ir, Pd, Pt, or Au) have been determined by equilibrating the alloy with the appropriate carbide and graphite, equilibrating with the nitride and nitrogen gas, or measuring the partial vapor pressure(s) thermogravimetrically or mass spectrometrically. The extraordinary stability of this class of transition metal alloy is attributed to a generalized Lewis-acid-base interaction involving valence d electrons, and the results of these investigations are interpreted within the context of this effect. Among the conclusions made are that a non-spherically-symmetrical crystal field significantly reduces the bonding effectiveness of certain valence d orbitals; the effect of the extent of derealization of these orbitals is also considered.

  10. Brazeability of a 3003 Aluminum alloy with Al-Si-Cu-based filler metals

    Science.gov (United States)

    Tsao, L. C.; Weng, W. P.; Cheng, M. D.; Tsao, C. W.; Chuang, T. H.

    2002-08-01

    Al-Si-Cu-based filler metals have been used successfully for brazing 6061 aluminum alloy as reported in the authors’ previous studies. For application in heat exchangers during manufacturing, the brazeability of 3003 aluminum alloy with these filler metals is herein further evaluated. Experimental results show that even at such a low temperature as 550 °C, the 3003 alloys can be brazed with the Al-Si-Cu fillers and display bonding strengths that are higher than 77 MPa as well. An optimized 3003 joint is attained in the brazements with the innovative Al-7Si-20Cu-2Sn-1Mg filler metal at 575 °C for 30 min, which reveals a bonding strength capping the 3003 Al matrix.

  11. Oxidation behavior of multiphase Mo5SiB2 (T2)-based alloys at high temperatures

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Two Mo5SiB2 (T2)-based alloys with nominal compositions of Mo-12.5Si-25B and Mo-14Si-28B (molar fraction, %)were prepared in an arc-melting furnace, and their oxidation kinetics from 1 000 to 1 300 ℃ were studied. The microstructures of the alloys were characterized by X-ray diffractometry(XRD) and scanning electron microscopy(SEM) with energy dispersive spectroscopy (EDS). The oxide scales of both alloys oxidized at 1 200 ℃ for 10 min, 2 h and 100 h were investigated by surface XRD and cross-sectional SEM-EDS. The results show that the matrix of both alloys consists of T2. The dispersions of Mo-12.5Si-25B alloy are Mo and Mo3Si, and the dispersions of Mo-14Si-28B alloy are Mo5Si3 (T1) and MoB. The cyclic oxidation kinetics data exhibit initial rapid mass loss followed by slow mass loss. The mass loss of Mo-12.5Si-25B alloy is much faster than that of Mo-14Si-28B alloy at 1 200 and 1 300 ℃. For 10 min exposure, both alloys form irregular and porous thin scale. For 2 h exposure, Mo-12.5Si-25B alloy forms irregular thin scale and the scale contains large cracks, and Mo-14Si-28B alloy forms sound and continuous scale. For 100 h exposure, Mo-12.5Si-25B and Mo-14Si-28B alloys form sound and continuous scale about 50-75 μm and 40-45 μm in thickness, respectively. The better oxidation resistance of Mo-14Si-28B alloy is due to a sound and continuous B-SiO2 layer formation in the early stage of oxidation.

  12. Self-standing nanoribbons of antimony selenide and antimony sulfide with well-defined size and band gap

    Energy Technology Data Exchange (ETDEWEB)

    Vadapoo, Rajasekarakumar; Krishnan, Sridevi; Yilmaz, Hulusi [Department of Physics, University of Puerto Rico, San Juan, PR 00936 (Puerto Rico); Marin, Carlos [Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00936 (United States)

    2011-04-29

    Sub-10 nm semiconducting nanostructures are crucial for the realization of nanoscale devices. Fabrication of nanostructures at this scale with homogeneous properties is challenging. Using ab initio calculations, we show that self-standing ribbons of antimony selenide and antimony sulfide of width 1.1 nm exhibit well-defined bandgaps of 1.66 and 2.16 eV, respectively. Molecular dynamics studies show that these ribbons are stable at 500 K. The one-dimensional (1D) heterostructure of these nanoribbons (Sb{sub 2}Se{sub 3}/Sb{sub 2}S{sub 3}) along the [001] direction shows a straddling type behavior.

  13. Selective oxidation of propene on bismuth molybdate and mixed oxides of tin and antimony and of uranium and antimony

    International Nuclear Information System (INIS)

    Propene + 1802 reactions have been studied in a static reaction system on bismuth molybdate and mixed oxides of tin and antimony and of uranium and antimony. The [160] acrolein content of the total acrolein formed and the proportion of 160 in the oxygen of the carbon dioxide by-product have been determined. The results indicate that for each catalyst the lattice is the only direct source of the oxygen in the aldehyde, and that lattice and/or gas phase oxygen is used in carbon dioxide formation. Oxygen anion mobility appears to be greater in the molybdate catalyst than in the other two. (author)

  14. Ambient-temperature high damping capacity in TiPd-based martensitic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Dezhen [Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Zhou, Yumei, E-mail: zhouyumei@mail.xjtu.edu.cn [Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Ding, Xiangdong [Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Otsuka, Kazuhiro [Ferroic Physics Group, National Institute for Materials Science, Tsukuba 305-0047, Ibaraki (Japan); Lookman, Turab [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Sun, Jun [Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Ren, Xiaobing [Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Ferroic Physics Group, National Institute for Materials Science, Tsukuba 305-0047, Ibaraki (Japan)

    2015-04-24

    Shape memory alloys (SMAs) have attracted considerable attention for their high damping capacities. Here we investigate the damping behavior of Ti{sub 50}(Pd{sub 50−x}D{sub x}) SMAs (D=Fe, Co, Mn, V) by dynamic mechanical analysis. We find that these alloys show remarkably similar damping behavior. There exists a sharp damping peak associated with the B2–B19 martensitic transformation and a high damping plateau (Q{sup −1}~0.02–0.05) over a wide ambient-temperature range (220–420 K) due to the hysteretic twin boundary motion. After doping hydrogen into the above alloys, a new relaxation-type damping peak appears in the martensite phase over 270–360 K. Such a peak is considered to originate from the interaction of hydrogen atoms with twin boundaries and the corresponding damping capacity (Q{sup −1}~0.05–0.09) is enhanced by roughly twice that of the damping plateau for each alloy. Moreover, the relaxation peaks are at higher temperatures for the TiPd-based alloys (270–370 K) than for the TiNi-based alloys (190–260 K). We discuss the influence of hydrogen diffusion, mobility of twin boundaries and hydrogen–twin boundary interaction on the temperature range of the relaxation peak. Our results suggest that a martensite, with appropriate values for twinning shear and hydrogen doping level, provides a route towards developing high damping SMAs for applications in desired temperature ranges.

  15. Fuel behavior in severe accidents and Mo-alloy based cladding designs to improve accident tolerance

    International Nuclear Information System (INIS)

    The severe accidents at TMI-2 and Fukushima-Daiichi led to core meltdown and hydrogen explosions. The main source of energy causing core melting is the decay heat from β-, β+, and γ decays of short-lived isotopes following a power scram. The exothermic reaction of Zr-alloy cladding can further increase the cladding temperature leading to rapid cladding corrosion and hydrogen production. The most effective mitigation to minimize core damage in a severe accident is to extend the duration of heat removal capacity via battery-supported passive cooling for as long as practically possible. Replacing the Zr-alloy cladding with a higher heat resistant cladding with lower enthalpy release rate may also provide additional coping time for accident management. Such a heat resistant cladding may also overcome the current licensing concerns about Zr-alloy hydriding and post quench ductility issues in a design base loss of coolant accident (LOCA). Zr-alloy cladding, while has been optimized for normal operation in high pressure water and steam of light water reactors, will rapidly lose its corrosion resistance and tensile and creep strength in high pressure steam. Evaluation of alternate cladding materials and designs have been performed to search for a new fuel cladding design which will substantially improve the safety margins at elevated temperatures during a severe accident, while maintaining the excellent fuel performance attributes of the current Zr-alloy cladding. The screening criteria for the evaluation include neutronic properties, material availability, adaptability and operability in current LWRs, resistance to melting. The new designs also need to be fabricable, maintain sufficient strength and resist to attack by high pressure steam. Engineering metals, alloys and ceramics which can meet some or most of these requirements are limited. Following review of the properties of potential candidates, it is concluded that molybdenum alloys may potentially achieve the

  16. Unusual glass-forming ability of new Zr-Cu-based bulk glassy alloys containing an immiscible element pair

    International Nuclear Information System (INIS)

    We herein report the unusual glass-forming ability (GFA) of a new series of quinary Zr48Cu36-xNixAg8Al8 (048Cu36Ag8Al8 alloy. By cooper mold casting, an as-cast glassy rod with a diameter of 30 mm can be easily obtained for the representative alloy Zr48Cu32Ni4Ag8Al8. The possible reasons for the excellent GFA of the new quinary alloys with an immiscible element pair are discussed based on the atomic size distribution, chemical compatibility among the components and atomic structure of glassy alloys. (author)

  17. Determination of arsenic, selenium and antimony by neutron activation analysis. Application to hair samples

    International Nuclear Information System (INIS)

    A fast rabbit system for instrumental activation analysis with reactor neutrons is described. Its use in the determination of selenium in hair is discussed. A survey is given of the correction factors which are inherent to the use of short-lived radionuclides. An alternative to INAA is NAA based on the separation of arsenic, selenium and antimony by hydride evaporation and adsorption to active carbon. Data for some Standard Reference Materials are given. This work was done under research contract 2440/RI/RB with the IAEA

  18. Phonon dispersion in alkali metals and their equiatomic sodium-based binary alloys

    Institute of Scientific and Technical Information of China (English)

    Aditya M. VORA

    2008-01-01

    In the present article, the theoretical calcula-tions of the phonon dispersion curves (PDCs) of five alkali metals viz. Li, Na, K, Rb, Cs and their four equia-tomic sodium-based binary alloys viz. Na0.5Li0.5,Na0.5K0.5, Na0.5Rb0.5 and Na0.5Cs0.5 to second order in a local model potential is discussed in terms of the real-space sum of the Born yon Karman central force con-stants. Instead of the concentration average of the force constants of pure alkali metals, the pseudo-alloy-atom (PAA) is adopted to directly compute the force constants of the four equiatomic sodium based binary alloys and was successfully applied. The exchange and correlation functions due to the Hartree (H) and Ichimaru-Utsumi (IU) are used to investigate the influence of the screening effects. The phonon frequencies of alkali metals and their four equiatomic sodium-based binary alloys in the longit-udinal branch are more sensitive to the exchange and cor-relation effects in comparison with the transverse branches. The PDCs of pure alkali metals are found in qualitative agreement with the available experimental data. The frequencies in the longitudinal branch are sup-pressed rather due to IU-screening function than those due to static H-screening function.

  19. Ni-Cr based dental alloys; Ni release, corrosion and biological evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Reclaru, L., E-mail: lucien.reclaru@pxgroup.com [PX Holding S.A., Dep R and D Corrosion and Biocompatibility Group, Bd. des Eplatures 42, CH-2304 La Chaux-de-Fonds (Switzerland); Unger, R.E.; Kirkpatrick, C.J. [Institute for Pathology, REPAIR Lab, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstr.1, D-55101 Mainz (Germany); Susz, C.; Eschler, P.-Y.; Zuercher, M.-H. [PX Holding S.A., Dep R and D Corrosion and Biocompatibility Group, Bd. des Eplatures 42, CH-2304 La Chaux-de-Fonds (Switzerland); Antoniac, I. [Materials Science and Engineering Faculty, Politehnica of Bucharest, 060042 Bucharest (Romania); Luethy, H. [Institute of Dental Materials Science and Technology, University of Basel, Hebelstrasse 3, CH-4056 Basel (Switzerland)

    2012-08-01

    In the last years the dental alloy market has undergone dramatic changes for reasons of economy and biocompatibility. Nickel based alloys have become widely used substitute for the much more expensive precious metal alloys. In Europe the prevalence of nickel allergy is 10-15% for female adults and 1-3% for male adults. Despite the restrictions imposed by the EU for the protection of the general population in contact dermatitis, the use of Ni-Cr dental alloys is on the increase. Some questions have to be faced regarding the safety risk of nickel contained in dental alloys. We have collected based on many EU markets, 8 Ni-Cr dental alloys. Microstructure characterization, corrosion resistance (generalized, crevice and pitting) in saliva and the quantities of cations released in particular nickel and CrVI have been evaluated. We have applied non parametric classification tests (Kendall rank correlation) for all chemical results. Also cytotoxicity tests and an evaluation specific to TNF-alpha have been conducted. According to the obtained results, it was found that their behavior to corrosion was weak but that nickel release was high. The quantities of nickel released are higher than the limits imposed in the EU concerning contact with the skin or piercing. Surprisingly the biological tests did not show any cytotoxic effect on Hela and L929 cells or any change in TNF-alpha expression in monocytic cells. The alloys did not show any proinflammatory response in endothelial cells as demonstrated by the absence of ICAM-1 induction. We note therefore that there is really no direct relationship between the in vitro biological evaluation tests and the physico-chemical characterization of these dental alloys. Clinical and epidemiological studies are required to clarify these aspects. - Highlights: Black-Right-Pointing-Pointer Nickel released was higher than the limits imposed in EU in contact with the skin. Black-Right-Pointing-Pointer No direct relationship between the

  20. Ni–Cr based dental alloys; Ni release, corrosion and biological evaluation

    International Nuclear Information System (INIS)

    In the last years the dental alloy market has undergone dramatic changes for reasons of economy and biocompatibility. Nickel based alloys have become widely used substitute for the much more expensive precious metal alloys. In Europe the prevalence of nickel allergy is 10–15% for female adults and 1–3% for male adults. Despite the restrictions imposed by the EU for the protection of the general population in contact dermatitis, the use of Ni–Cr dental alloys is on the increase. Some questions have to be faced regarding the safety risk of nickel contained in dental alloys. We have collected based on many EU markets, 8 Ni–Cr dental alloys. Microstructure characterization, corrosion resistance (generalized, crevice and pitting) in saliva and the quantities of cations released in particular nickel and CrVI have been evaluated. We have applied non parametric classification tests (Kendall rank correlation) for all chemical results. Also cytotoxicity tests and an evaluation specific to TNF-alpha have been conducted. According to the obtained results, it was found that their behavior to corrosion was weak but that nickel release was high. The quantities of nickel released are higher than the limits imposed in the EU concerning contact with the skin or piercing. Surprisingly the biological tests did not show any cytotoxic effect on Hela and L929 cells or any change in TNF-alpha expression in monocytic cells. The alloys did not show any proinflammatory response in endothelial cells as demonstrated by the absence of ICAM-1 induction. We note therefore that there is really no direct relationship between the in vitro biological evaluation tests and the physico-chemical characterization of these dental alloys. Clinical and epidemiological studies are required to clarify these aspects. - Highlights: ► Nickel released was higher than the limits imposed in EU in contact with the skin. ► No direct relationship between the biological evaluation and chemical degradation.

  1. On the nature of the variation of martensitic transformation hysteresis and SME characteristics in Fe-Ni-base alloys

    International Nuclear Information System (INIS)

    The purpose of this paper is to summarize the various investigations, both by the authors and other works, concerning with the martensitic transformation and SME in Fe-Ni-base alloys. The thermal hysteresis dependence on the alloying elements and thermal treatments are surveyed. The contribution and effect on SME characteristics of widely used alloying elements such as Ti, Nb, Ni, Al, Co, Ta and peculiarities of thermal treatment are discussed. It is noted the main goal of these treatments is to reduce the symmetry of transformation by the ordering or precipitation of a fine coherent phase. The physical principles of transformation hysteresis manipulation in Fe-base alloys is discussed and it concluded that the thermal cycling behavior of Fe-base alloys is very complex and is not clearly understood at present. On the other hand, it is pointed out that thermal cycling is an effective method for control and improvement of SME in these alloys. It is concluded that Fe-base alloys are highly evolved shape memory materials-having a wide working range, good workability and are relatively cheap. In addition, the properties are easily controlled by suitably alloying, aging and thermal cycling. (orig.)

  2. Antimony to Cure Visceral Leishmaniasis Unresponsive to Liposomal Amphotericin B

    Science.gov (United States)

    Morizot, Gloria; Jouffroy, Romain; Faye, Albert; Chabert, Paul; Belhouari, Katia; Calin, Ruxandra; Charlier, Caroline; Miailhes, Patrick; Siriez, Jean-Yves; Mouri, Oussama; Yera, Hélène; Gilquin, Jacques; Tubiana, Roland; Lanternier, Fanny; Mamzer, Marie-France; Legendre, Christophe; Peyramond, Dominique; Caumes, Eric; Lortholary, Olivier; Buffet, Pierre

    2016-01-01

    We report on 4 patients (1 immunocompetent, 3 immunosuppressed) in whom visceral leishmaniasis had become unresponsive to (or had relapsed after) treatment with appropriate doses of liposomal amphotericin B. Under close follow-up, full courses of pentavalent antimony were administered without life-threatening adverse events and resulted in rapid and sustained clinical and parasitological cure. PMID:26735920

  3. Vapor pressures of dimethylcadmium, trimethylbismuth, and tris(dimethylamino)antimony

    Czech Academy of Sciences Publication Activity Database

    Morávek, Pavel; Fulem, Michal; Pangrác, Jiří; Hulicius, Eduard; Růžička, K.

    2013-01-01

    Roč. 360, Dec (2013), s. 106-110. ISSN 0378-3812 R&D Projects: GA ČR GA13-15286S; GA MŠk(CZ) LM2011026 Institutional support: RVO:68378271 Keywords : vapor pressure * dimethylcadmium * trimethylbismuth * tris(dimethylamino)antimony * sublimation and vaporization enthalpy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.241, year: 2013

  4. Discovery of palladium, antimony, tellurium, iodine, and xenon isotopes

    OpenAIRE

    Kathawa, J.; Fry, C; Thoennessen, M

    2012-01-01

    Currently, thirty-eight palladium, thirty-eight antimony, thirty-nine tellurium, thirty-eight iodine, and forty xenon isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

  5. Vacuum distillation of antimony-mercury gold containing concentrates

    International Nuclear Information System (INIS)

    Results of researches on vacuum distillation of mercury from gold containing antimony-mercury concentrates are considered in this article. It is shown that at vacuum of 20-50 mm Hg and temperature 300 deg C mercury is sublimated and gold remain in a cinder. (author)

  6. Antimony content of macrofungi from clean and polluted areas

    Czech Academy of Sciences Publication Activity Database

    Borovička, J.; Řanda, Zdeněk; Jelínek, E.

    2006-01-01

    Roč. 64, č. 11 (2006), s. 1837-1844. ISSN 0045-6535 Institutional research plan: CEZ:AV0Z10480505 Keywords : mushrooms * antimony pollution * bioaccumulation Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.442, year: 2006

  7. Frenkel defects in Ni and Ni-base alloys

    International Nuclear Information System (INIS)

    The defect structure produced by low temperature (4K) electron irradiation in single crystals of Ni, Ni62Cu38 and Ni3 Fe was investigated by measurements of the diffuse scattering of X-rays (Huang Diffuse Scattering), the change of the lattice parameter and the change of the electrical resistivity: The volume relaxation and the structure of the self interstitial atom (SIA) is very similar for the alloys and the pure fcc metals. The interstitial clustering processes during stage I and II proceed progressively more slowly in Cu, Ni, NiCu and Ni3Fe respectively. In Ni3Fe even the di-interstitial seems immobile up to stage III. The formation of large vacancy agglomerates during stage III annealing is only observed with the pure metals Ni and Cu. Interstitial mobility during annealing in stage II contributes to the decomposition of NiCu but not to the ordering of Ni3Fe. There is an increase of order for highly ordered Ni3Fe (S = 0.7) during annealing in stage III and, within the errors, no change for samples with S = 0. (author)

  8. Hydrogen distribution in amorphous silicon and silicon based alloys

    International Nuclear Information System (INIS)

    The results of hydrogen evolution experiments on amorphous silicon alloys prepared by high frequency PECVD of gas mixtures containing SiH4, NH3, PH2, B2H6 are compared. Using a very low heating rate of 5 degree/min it is possible to resolve fine structure on the exodiffusion spectra. Three evolution processes are observed: (a) low temperature effusion due to included gas (b) mid temperature effusion due to 'clustered' hydrogen bonds (c) high temperature effusion due to 'isolated' hydrogen bonds In addition it is possible to oberve very fine structure 'puffing' due to the release of molecular hydrogen at mid to high temperature. Silicon and silicon nitride films have been annealed at low temperatures before the exodiffusion experiments and changes in the evolution spectra are observed, dependent on the annealing process. A scanning electron microscope study of the effect of high temperature heat treatment has also been undertaken. These results are correlated with infra-red absorption measurements and the influence of doping concentration and substrate character discussed. Under certain preparation conditions the films blister on heating and finally burst forming circular craters, and these effects are shown to be dependent on substrate material and intrinsic stress of the as-grown films

  9. The surface layer degradation of γ-TiAl phase based alloy

    Directory of Open Access Journals (Sweden)

    J. Małecka

    2013-05-01

    Full Text Available Purpose: The aim of the present research is to describe the chemical composition and microstructure of the surface layer of Ti-46Al-7Nb-0.7Cr-0,1Si-0.2Ni alloy after the test of isothermal oxidation in 9%O2+0.2%HCl+0.08%SO2+N2 during 250 h. Design/methodology/approach: The objectives were achieved using several techniques including conventional metallography, SEM, BSE, EDX. The oxides scales and their effects were investigated at temperatures 750ºC.Findings: This investigation confirms that the better protection of the substrate was determined using AlCrN coating.Research limitations/implications: The basic limitations concern alloys in a higher temperature and establish the oxidation kinetics of the analysed alloy as a function of time and temperature.Practical implications: One of practical outcomes is to select the coatings which guarantee the reduction of oxidation behavior. It is recommended to use alloys with AlCrN coating.Originality/value: Original value of the paper is assessing of the oxidation resistance of Ti-46Al-7Nb-0.7Cr-0.1Si–0.2Ni-based intermetallic alloy at the conditions combining high temperature and sulphur and chlorine compounds-containing atmosphere. The novelty of this research deals with the mechanism of oxidation at such boundary conditions. This knowledge can support the design of parts made of the intermetallic alloy. The problem considered is currently important for aeroplane and automotive industry, especially for gas turbine manufacturers.

  10. Solidification Processing of Te–Sb–Pb Alloys For Thermoelectric Applications

    OpenAIRE

    Ikeda, Teruyuki; Azizgolshani, Hesham; Haile, Sossina; Snyder, G. Jeffrey; Ravi, Vilupanur

    2005-01-01

    A solidification processing approach to the refinement of lead-tellurium-antimony alloy microstructure is described. Liquid alloys with eutectic, hyper-eutectic and hypo-eutectic compositions (relative to lead) were cooled to the solid state in three distinct ways, i.e. by water quenching, air cooling and furnace cooling. The structures of the alloys resulting from the three different solidification paths were examined using electron microscopy and the micrographs were quantified. Classical s...

  11. Research on CMT welding of nickel-based alloy with stainless steel

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Cold Metal Transfer (CMT) welding technique is a new welding technique introduced by Fronius company. CMT welding of nickel-based alloy with stainless steel was carried out using CuSi3 filler wire in this paper. Effects of welding parameters, including welding current, welding speed, etc, on weld surface appearance were tested. Microstructure and mechanical properties of CMT weld were studied. The results show that the thickness of interface reaction layer of the nickel-based alloy is 14.3μm, which is only 4.33% of base material. The weld is made up of two phases,α-copper and iron-based solid solution. Rupture occurs initially at the welded seam near the edge of stainless steel in shear test. The maximum shear strength of the CuSi3 welded joint is 184.9MPa.

  12. The electronic mechanism of the γ/γ' interface strength of Ir-based alloys

    International Nuclear Information System (INIS)

    The electronic structures of the γ/γ' interface for two-phase Ir-based alloys (Ir/Ir3Ta and Ir/Ir3Ti) have been investigated by performing first-principles quantum mechanics DMol3 (a type of density functional theory for molecules) calculations. The Mayer bond order (MBO) is used to represent the shear and cohesion strengths of the interface by a local sum of the horizontal and vertical MBOs. By comparison with those for single-crystal Ir, the results show that both the cohesive and shear strengths of the γ/γ' interface for the Ir/Ir3Ta alloy increase. The cohesive strength of the interface for the Ir/Ir3Ti alloy increases, whereas the shear strength of the interface for Ir/Ir3Ti decreases. The electron charge density, the Hirshfeld charge, and orbital charge transfers are also calculated and analysed. An electronic mechanism for the γ/γ' interface strength of Ir-based alloys is then suggested

  13. Fundamental aspects of corrosion on zirconium base alloys in water reactor environments

    International Nuclear Information System (INIS)

    The purpose of this meeting was to discuss the state of knowledge of zirconium alloy corrosion mechanisms. Forty-five participants from 16 countries attended the meeting, and 25 papers were presented and discussed. One additional paper was provided only in written form. The papers were presented in seven sub-sessions under the following headings: Electrochemistry, Coolant Chemistry Effects, Irradiation Effects, Characteristics of Zirconium Oxide, Effects of Alloying on Corrosion, Corrosion Modeling and Effect of Zirconium Base Metal Properties on Corrosion. There is still a need for a laboratory corrosion test that reliably predicts in-pile corrosion in BWR's and PWR's. This holds particularly if out-of-pile tests are used for developing new Zr base alloy compositions. The role of the precipitates and of the solute elements in the matrix has still to be clarified. As it appears, a combination of both influences is necessary to explain the mechanistic aspect of the corrosion of Zircaloy. It is clear that mechanistic understanding of zirconium alloy corrosion is still some way off, although a significant amount of progress has been made toward experimental determination of the micro-scale phenomena. The papers presented a status report of our knowledge of these corrosion mechanisms, but they also served to illustrate the fact that much of the work done to date has been phenomenological rather than mechanistic. The summaries of individual sessions detail the specific conclusions and recommendations made at the meeting. Refs, figs and tabs

  14. Solid particle erosion of steels and nickel based alloys candidates for USC steam turbine blading

    Energy Technology Data Exchange (ETDEWEB)

    Cernuschi, Federico; Guardamagna, Cristina; Lorenzoni, Lorenzo [ERSE SpA, Milan (Italy); Robba, Davide [CESI, Milan (Italy)

    2010-07-01

    The main objective of COST536 Action is to develop highly efficient steam power plant with low emissions, from innovative alloy development to validation of component integrity. In this perspective, to improve the operating efficiency, materials capable of withstanding higher operating temperatures are required. For the manufacturing of components for steam power plants with higher efficiency steels and nickel-based alloys with improved oxidation resistance and creep strength at temperature as high as 650 C - 700 C have to be developed. Candidate alloys for manufacturing high pressure steam turbine diaphragms, buckets, radial seals and control valves should exhibit, among other properties, a good resistance at the erosion phenomena induced by hard solid particles. Ferric oxide (magnetite) scales cause SPE by exfoliating from boiler tubes and steam pipes (mainly super-heaters and re-heaters) and being transported within the steam flow to the turbine. In order to comparatively study the erosion behaviour of different materials in relatively short times, an accelerated experimental simulation of the erosion phenomena must be carried out. Among different techniques to induce erosion on material targets, the use of an air jet tester is well recognised to be one of the most valid and reliable. In this work the results of SPE comparative tests performed at high temperatures (550 C, 600 C and 650 C) at different impaction angles on some steels and nickel based alloys samples are reported. (orig.)

  15. A study of electron beam welding of Mo based TZM alloy

    International Nuclear Information System (INIS)

    Mo based TZM alloy is one of the most promising refractory alloy having several unique high temperature properties suitable for structural applications in the new generation advanced nuclear reactors. However, this alloy easily picks up interstitial impurities such as N2, H2 and C from air during welding due to its reactive nature. High melting point of TZM alloy also restricts use of conventional welding technique for welding. Hence, Electron beam welding (EBW) technique with its deep penetration power to produce narrow heat affected zones under high vacuum was employed to overcome the above welding constraints by conducting a systematic study using both processes of bead on plate and butt joint configuration. Uniform and defect free weld joints were produced. Weld joints were subjected to optical characterization, chemical homogeneity analysis and microhardness profile study across the width of welds. Improved grain structure with equiaxed grains was obtained in the weld zone as compared to fibrous base structure. Original chemical composition was retained in the weld zone. The detailed results are described in this report. (author)

  16. Optical modeling of nickel-base alloys oxidized in pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Clair, A. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon cedex (France); Foucault, M.; Calonne, O. [Areva ANP, Centre Technique Departement Corrosion-Chimie, 30 Bd de l' industrie, BP 181, 71205 Le Creusot (France); Finot, E., E-mail: Eric.Finot@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon cedex (France)

    2012-10-01

    The knowledge of the aging process involved in the primary water of pressurized water reactor entails investigating a mixed growth mechanism in the corrosion of nickel-base alloys. A mixed growth induces an anionic inner oxide and a cationic diffusion parallel to a dissolution-precipitation process forms the outer zone. The in situ monitoring of the oxidation kinetics requires the modeling of the oxide layer stratification with the full knowledge of the optical constants related to each component. Here, we report the dielectric constants of the alloys 600 and 690 measured by spectroscopic ellipsometry and fitted to a Drude-Lorentz model. A robust optical stratification model was determined using focused ion beam cross-section of thin foils examined by transmission electron microscopy. Dielectric constants of the inner oxide layer depleted in chromium were assimilated to those of the nickel thin film. The optical constants of both the spinels and extern layer were determined. - Highlights: Black-Right-Pointing-Pointer Spectroscopic ellipsometry of Ni-base alloy oxidation in pressurized water reactor Black-Right-Pointing-Pointer Measurements of the dielectric constants of the alloys Black-Right-Pointing-Pointer Optical simulation of the mixed oxidation process using a three stack model Black-Right-Pointing-Pointer Scattered crystallites cationic outer layer; linear Ni-gradient bottom layer Black-Right-Pointing-Pointer Determination of the refractive index of the spinel and the Cr{sub 2}O{sub 3} layers.

  17. Modeling of self-controlling hyperthermia based on nickel alloy ferrofluids: Proposition of new nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Delavari, H. Hamid, E-mail: Hamid.delavari@gmail.com [Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Azadi Avenue, 145888-9694 Tehran (Iran, Islamic Republic of); Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala (Sweden); Madaah Hosseini, Hamid R. [Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Azadi Avenue, 145888-9694 Tehran (Iran, Islamic Republic of); Department of Materials Science and Engineering, Sharif University of Technology, Azadi Avenue, 145888-9694 Tehran (Iran, Islamic Republic of); Wolff, Max, E-mail: Max.wolff@physics.uu.se [Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala (Sweden)

    2013-06-15

    In order to provide sufficient heat without overheating healthy tissue in magnetic fluid hyperthermia (MFH), a careful design of the magnetic properties of nanoparticles is essential. We perform a systematic calculation of magnetic properties of Ni-alloy nanoparticles. Stoner–Wohlfarth model based theories (SWMBTs) are considered and the linear response theory (LRT) is used to extract the hysteresis loop of nickel alloy nanoparticles in alternating magnetic fields. It is demonstrated that in the safe range of magnetic field intensity and frequency the LRT cannot be used for the calculation of the area in the hysteresis for magnetic fields relevant for hyperthermia. The best composition and particle size for self-controlling hyperthermia with nickel alloys is determined based on SWMBTs. It is concluded that Ni–V and Ni–Zn are good candidates for self-controlling hyperthermia. - Highlights: ► Systematic calculation of magnetic properties of Ni-alloy NPs with composition has been performed. ► Optimum composition and particle size for self-controlling hyperthermia (SCH) have been determined. ► Ni–V and Ni–Zn nanoparticles are more appropriate candidates for SCH.

  18. Biocorrosion behavior and cell viability of adhesive polymer coated magnesium based alloys for medical implants

    Science.gov (United States)

    Abdal-hay, Abdalla; Dewidar, Montasser; Lim, Jae Kyoo

    2012-11-01

    The present study was ultimately aimed to design novel adhesive biodegradable polymer, poly(vinyl acetate) (PVAc), coatings onto Mg based alloys by the dip-coating technique in order to control the degradation rate and enhance the biocompatibility of magnesium alloys. The influence of various solvents on PVAc surface topography and their protection of Mg alloys were dramatically studied in vitro. Electrochemical polarization, degradation, and PVAc film cytocompatibility were also tested. Our results showed that the solvent had a significant effect on coating quality. PVAc/dichloromethane solution showed a porous structure and solution concentration could control the porous size. The coatings prepared using tetrahydrofuran and dimethylformamide solvents are exceptional in their ability to generate porous morphology even at low polymer concentration. In general, the corrosion performance appears to be different on different PVAc-solvent system. Immersion tests illustrated that the porous morphology on PVAc stabilized corrosion rates. A uniform corrosion attack in artificial simulation body fluid was also exhibited. The cytocompatibility of osteoblast cells (MC3T3) revealed high adherence, proliferation, and survival on the porous structure of PVAc coated Mg alloy, which was not observed for the uncoated samples. This novel PVAc coating is a promising candidate for biodegradable implant materials, which might widen the use of Mg based implants.

  19. The creep Kinetics of sand cat zinc-based alloys no. 2, ACuZinc5, and ACuzinc10

    International Nuclear Information System (INIS)

    Compressive creep tests have been carried out on three sand cast zinc-rich alloys No. 2 (Zn-4% Al-2.8% Cu 0.03% Mg), ACuZinc5 (Zn-3% Al-5.2% Cu-0.04% Mg) and ACuZinc10 (Zn-3.5% Al-9.3% Cu-0.03% Mg) in the stress range 20 to 100 MPa, and at temperatures from 70 to 160 deg. centigrade. The tests were performed on a standard weight lever arm compressive creep machine. Alloy No. 2 is a conventional zinc alloy, whereas ACuZinc5 and ACuZinc10 belong to a family of new, GM-patented, high performance ternary zin-copper-aluminium alloys which are suitable for manufacturing net shape die castings. Along with creep, other properties of ACuZinc alloys are claimed to be better than conventional zinc alloys No. 3 and No. 5 and ZA alloys, i.e. ZA.8, ZA.12 and ZA.27. A parametric relationship was obeyed, of the form:In t=C-n(In sigma)+Q/RTm where C is a constant, sigma the applied stress, t time of test, n the stress exponent, Q the activation energy, R the gas constant, and T is the absolute temperature. The primary creep contraction was generally found to increase with increasing copper content, but in a non-linear fashion. The secondary creep rates of alloy No. 2 were slightly lower than those of ACuZinc5 and ACuZinc10. Based on the above equation, continuous design stresses were calculated under different testing conditions which showed that both ACuZinc alloys were inferior in creep strength to alloy No.2 due to its lower secondary creep rates. The results and microstructure of alloys also showed that in all three alloys, the creep-controlling mechanism is the dislocation climb over second-phase (Epsilon) particles. (author)

  20. Development of an Electromagnetic Wave Shielding Textile by Electroless Ni-Based Alloy Plating

    OpenAIRE

    Sonehara, Makoto; Noguchi, Shin; Kurashina, Tadashi; Sato, Toshiro; YAMASAWA, Kiyohito; Miura, Yoshimasa

    2009-01-01

    A polyester nonwoven textile with Ni-based alloy coating was fabricated, and the effect of electromagnetic wave shielding was evaluated. The Ni-based was coated by electroless plating on the textile. The electromagnetic wave shielding effect of the textile with Ni-B coating was about 99.98% over the induction range of 6-13 GHz. Because the textile has thin, light, flexible, and breathable characteristics, it will be versatile for the various electromagnetic wave shielding applications.

  1. Antimony and arsenic biogeochemistry in the East China Sea

    Science.gov (United States)

    Ren, Jing-Ling; Zhang, Xu-Zhou; Sun, You-Xu; Liu, Su-Mei; Huang, Daji; Zhang, Jing

    2016-02-01

    The biogeochemical cycles of the metalloid elements arsenic and antimony in the East China Sea (ECS), one of the most important marginal seas for western Pacific, were examined in May 2011. Dissolved inorganic arsenic (As(V) and As(III)) and antimony (Sb(V) and Sb(III)) species were determined by selective hydride generation-atomic fluorescence spectrometry (HG-AFS). Results show that total dissolved inorganic arsenic (TDIAs; [TDIAs]=[As(V)]+[As(III)]) were moderately depleted in the surface water and enriched in the deep water. Arsenite (As(III)) showed different vertical profiles with that of TDIAs, with significant surface enrichment in the middle shelf region where the concentrations of phosphate were extremely low. Speciation of dissolved arsenic was subtly controlled by the stoichiometric molar ratio of arsenate (As(V)) to phosphate. The average As(V)/P ratio for the ECS in spring 2011 was 10.8×10-3, which is higher than previous results and indicates the arsenate stress. The concentrations of total dissolved inorganic antimony (TDISb; [TDISb]=[Sb(V)]+[Sb(III)]) were high near the Changjiang Estuary and the coastal area of Hangzhou Bay and decreased moderately off the coast. TDISb displayed moderate conservative behavior in the ECS that confirms by the correlations with salinity and dissolved aluminum. Different with that of As(III), antimonite (Sb(III)) concentrations were extremely lower in the ECS, with relative higher concentration appeared at the bottom layer which indicates the contribution from sediment-water interface. A preliminary box model was established to estimate the water-mass balance and antimony budgets for the ECS. Compared with other areas in the world, the concentrations of dissolved inorganic arsenic and antimony in the ECS remain at natural levels.

  2. Breaking through the strength-ductility trade-off dilemma in an Al-Si-based casting alloy.

    Science.gov (United States)

    Dang, B; Zhang, X; Chen, Y Z; Chen, C X; Wang, H T; Liu, F

    2016-01-01

    Al-Si-based casting alloys have a great potential in various industrial applications. Common strengthening strategies on these alloys are accompanied inevitably by sacrifice of ductility, known as strength-ductility trade-off dilemma. Here, we report a simple route by combining rapid solidification (RS) with a post-solidification heat treatment (PHT), i.e. a RS + PHT route, to break through this dilemma using a commercial Al-Si-based casting alloy (A356 alloy) as an example. It is shown that yield strength and elongation to failure of the RS + PHT processed alloy are elevated simultaneously by increasing the cooling rate upon RS, which are not influenced by subsequent T6 heat treatment. Breaking through the dilemma is attributed to the hierarchical microstructure formed by the RS + PHT route, i.e. highly dispersed nanoscale Si particles in Al dendrites and nanoscale Al particles decorated in eutectic Si. Simplicity of the RS + PHT route makes it being suitable for industrial scaling production. The strategy of engineering microstructures offers a general pathway in tailoring mechanical properties of other Al-Si-based alloys. Moreover, the remarkably enhanced ductility of A356 alloy not only permits strengthening further the material by work hardening but also enables possibly conventional solid-state forming of the material, thus extending the applications of such an alloy. PMID:27502444

  3. Breaking through the strength-ductility trade-off dilemma in an Al-Si-based casting alloy

    Science.gov (United States)

    Dang, B.; Zhang, X.; Chen, Y. Z.; Chen, C. X.; Wang, H. T.; Liu, F.

    2016-08-01

    Al-Si-based casting alloys have a great potential in various industrial applications. Common strengthening strategies on these alloys are accompanied inevitably by sacrifice of ductility, known as strength-ductility trade-off dilemma. Here, we report a simple route by combining rapid solidification (RS) with a post-solidification heat treatment (PHT), i.e. a RS + PHT route, to break through this dilemma using a commercial Al-Si-based casting alloy (A356 alloy) as an example. It is shown that yield strength and elongation to failure of the RS + PHT processed alloy are elevated simultaneously by increasing the cooling rate upon RS, which are not influenced by subsequent T6 heat treatment. Breaking through the dilemma is attributed to the hierarchical microstructure formed by the RS + PHT route, i.e. highly dispersed nanoscale Si particles in Al dendrites and nanoscale Al particles decorated in eutectic Si. Simplicity of the RS + PHT route makes it being suitable for industrial scaling production. The strategy of engineering microstructures offers a general pathway in tailoring mechanical properties of other Al-Si-based alloys. Moreover, the remarkably enhanced ductility of A356 alloy not only permits strengthening further the material by work hardening but also enables possibly conventional solid-state forming of the material, thus extending the applications of such an alloy.

  4. Thermodynamic prediction of thixoformability in alloys based on the Al-Si-Cu and Al-Si-Cu-Mg systems

    Energy Technology Data Exchange (ETDEWEB)

    Liu, D. [Department of Engineering, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Atkinson, H.V. [Department of Engineering, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Jones, H. [Department of Engineering Materials, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD (United Kingdom)

    2005-08-15

    Most commercial semi-solid processing (of which thixoforming is one type) utilises the conventional casting alloys A356 and A357. There is, however, a demand to widen the range of alloys, including those with higher performance which tend to show poor characteristics for thixoforming. Thermodynamic calculation packages, such as MTDATA, provide a tool for predicting thixoformability. Here, the effects of compositional variations, in particular the effect of added copper on the thixoformability of alloy A356 and the effect of added silicon on the thixoformability of alloy 2014, have been investigated using MTDATA thermodynamic and phase equilibrium software combined with the MTAL database. Criteria for thixoformability are identified and a range of alloy compositions based on Al-Si-Cu and Al-Si-Cu-Mg evaluated in relation to these criteria. Compositions which satisfy these criteria include: 308 (Al-5.5Si-4.5Cu); 319 (Al-6Si-3.5Cu); 238 (Al-10Cu-4Si-0.3Mg); 355 (Al-5Si-1.3Cu-0.5Mg); 2014 based alloys Al-4.4Cu-0.5Mg-(4-6)Si; and a range of alloys (7.5 Si + Cu 9 and 1.5 Si/Cu 2.33) and alloys (9 < Si + Cu 10 and Si/Cu = 1.5) based on the Al-Si-Cu-Mg system.

  5. Exploring screen printing technology on thermoelectric energy harvesting with printing copper-nickel and bismuth-antimony thermocouples

    OpenAIRE

    Cao, Zhuo; Koukharenko, Elena; Torah, R; Beeby, SP

    2013-01-01

    This paper reports the fabrication and testing of copper (Cu) - nickel (Ni) and bismuth (Bi) - antimony (Sb) based thermocouples fabricated using screen printing technology. The transport properties of the printed thermoelectric material were measured in room temperature while the Seebeck voltage and power output of the printed thermocouples were tested under a variety temperature gradient. Initial thermoelectric materials have been integrated in inks and then deposited on substrate by the si...

  6. Antimony film sensor for sensitive rare earth metal analysis in environmental samples.

    Science.gov (United States)

    Makombe, Martin; van der Horst, Charlton; Silwana, Bongiwe; Iwuoha, Emmanuel; Somerset, Vernon

    2016-07-01

    A sensor for the adsorptive stripping voltammetric determination of rare earth elements has been developed. The electrochemical procedure is based on the oxidation of the rare earth elements complexed with alizarin complexone at a glassy carbon electrode that was in situ modified with an antimony film, during an anodic scan from -0.2 V to 1.1 V (vs. Ag/AgCl) and deposition potential of -0.1 V (vs. Ag/AgCl). The factors influencing the adsorptive stripping capability were optimised, including the complexing agent concentration, plating concentration of antimony and deposition time. The detection of rare earth elements (La, Ce and Pr) were realised in 0.08 M sodium acetate (pH = 5.8) solution as supporting electrolyte, with 2 × 10(-6) M alizarin complexone and 1.0 mg L(-1) antimony solution. Under the optimised conditions, a deposition time of 360 s was obtained and a linear response was observed between 1 and 25 µg L(-1). The reproducibility of the voltammetric measurements was found to be within 5.0% RSD for 12 replicate measurements of cerium(III) concentration of 5 µg L(-1) using the same electrode surface. The detection limits obtained using stripping analysis was 0.06, 0.42 and 0.71 μg L(-1) for Ce(III), La(III) and Pr(III), respectively. The developed sensor has been successfully applied for the determination of cerium, lanthanum and praseodymium in municipal tap water samples. PMID:27065049

  7. The kinetics of phase transformations of undercooled austenite of the Mn-Ni iron based model alloy

    Directory of Open Access Journals (Sweden)

    E. Rożniata

    2011-12-01

    Full Text Available Purpose: Present work corresponds to the research on the kinetics of phase transformations of undercooled austenite of Mn-Ni iron based model alloy. The kinetics of phase transformations of undercooled austenite of investigated alloy was presented on CCT diagram (continuous cooling transformation. Also the methodology of a dilatometric samples preparation and the method of the critical points determination were described.Design/methodology/approach: The austenitising temperature was defined in a standard way i.e. 30-50°C higher than Ac3 temperature for model alloy. A technique of full annealing was proposed for the model alloy. The CCT diagrams were made on the basis of dilatograms recorded for samples cooled at various rates. The microstructure of each dilatometric sample was photographed after its cooling to the room temperature and the hardness of the samples was measured.Findings: The test material was a Mn-Ni hypoeutectoid iron based alloy. The microstructure of test Mn-Ni alloy on CCT diagram changes depending on the cooling rate. At the cooling rates of 10°C/s and 5°C/s there is ferrite in Widmannstätten structure present in the structure of tested alloy.Research limitations/implications: The new Mn-Ni iron based model alloy and a new CCT diagram.Practical implications: The paper contains a description of one from a group of iron based model alloys with 0.35-0.40% carbon content. According to PN-EN 10027 standard this steel should have a symbol 38MnNi6-4.Originality/value: The new Mn-Ni iron based model alloy.

  8. The resistance to embrittlement by a hydrogen environment of selected high strength iron-manganese base alloys

    Science.gov (United States)

    Benson, R. B., Jr.; Kim, D. K.; Atteridge, D.; Gerberich, W. W.

    1974-01-01

    Fe-16Mn and Fe-25Mn base alloys, which had been cold worked to yield strength levels of 201 and 178 KSI, were resistant to degradation of mechanical properties in a one atmosphere hydrogen environment at ambient temperature under the loading conditions employed in this investigation. Transmission electron microscopy established that bands of epsilon phase martensite and fcc mechanical twins were formed throughout the fcc matrix when these alloys were cold worked. In the cold worked alloys a high density of crystal defects were observed associated with both types of strain induced structures, which should contribute significantly to the strengthening of these alloys. High strength iron base alloys can be produced which appear to have some resistance to degradation of mechanical properties in a hydrogen environment under certain conditions.

  9. Chromium activity measurements in nickel based alloys for very high temperature reactors: Inconel 617, haynes 230 and model alloys - HTR2008-58147

    International Nuclear Information System (INIS)

    The alloys Haynes 230 and Inconel 617 are potential candidates for the intermediate heat exchangers (IHX) of (V)-HTR reactors. The behaviour under corrosion of these alloys by the (V)-HTR coolant (impure helium) is an important selection criterion because it defines the service life of these components. At high temperature, the Haynes 230 is likely to develop a chromium oxide on the surface. This layer protects from the exchanges with the surrounding medium and thus confers certain passivity on metal. At very high temperature, the initial microstructure made up of austenitic grains and coarse intra and intergranular M6C carbide grains rich in W will evolve. The M6C carbides remain and some M23C6 richer in Cr appear. Then, carbon can reduce the protective oxide layer Then, the alloy loses its protective coating and can corrode quickly. Experimental investigations were performed on these nickel based alloys under an impure helium flow [1]. To predict the surface reactivity of chromium under impure helium, it is necessary to determine its chemical activity in a temperature range close to the operating conditions of the heat exchangers (T∼1273 K). For that, high temperature mass spectrometry measurements coupled to multiple effusion Knudsen cells are carried out on several samples: Haynes 230, Inconel 617 and model alloys 1178, 1181, 1201. This coupling makes it possible thermodynamic equilibrium to be obtained between the vapour phase and the condensed phase of the sample. The measurement of the chromium ionic intensity (/) of the molecular beam resulting from a cell containing an alloy provides the values of partial pressure according to the temperature. This value is compared to that of the pure substance (Cr) at the same temperature. These calculations provide thermodynamic data characteristic of the chromium behaviour in these alloys. These activity results call into question those previously measured by Hilpert [2], largely used in the literature. (authors)

  10. Qualification of new filler metal made of high chromium content nickel base alloy

    International Nuclear Information System (INIS)

    A study has been carried out by EDF and FRAMATOME in the context of the French Association for design and manufacturing rules of nuclear power boiler's equipment, to research then qualify filler metals dedicated to the welding of the new nickel base including 30 % chromium alloy components of PWR. The aim is to assess their weldability and their stress corrosion behaviour in the conditions prevailing in the primary cooling system of PWR and to compare with products generally used. Moreover, numerous qualification tests have been carried out to verify that such metals meet the criteria accepted in the RCC-M code. Results allowed to qualify some filler metals made of nickel base alloy of qualify equivalent to the one of NC30Fe including 30 % chromium base metals. These metals are at present time used in manufacturing. (authors). 5 figs

  11. Microstructural characterization of a new mechanically alloyed Ni-base ODS superalloy powder

    Energy Technology Data Exchange (ETDEWEB)

    Seyyed Aghamiri, S.M. [Department of Materials Engineering, Tarbiat Modares University, Tehran 14115-143 (Iran, Islamic Republic of); Shahverdi, H.R., E-mail: Shahverdi@modares.ac.ir [Department of Materials Engineering, Tarbiat Modares University, Tehran 14115-143 (Iran, Islamic Republic of); Ukai, S.; Oono, N.; Taya, K.; Miura, S.; Hayashi, S. [Material Science and Engineering, Faculty of Engineering, Hokkaido University, Sapporo 060-8626 (Japan); Okuda, T. [Kobelco Research Institute Ltd., Kobe 651-2271 (Japan)

    2015-02-15

    The microstructure of a new Ni-base oxide dispersion strengthened superalloy powder was studied for high temperature gas turbine applications after the mechanical alloying process. In this study, an atomized powder with a composition similar to the CMSX-10 superalloy was mechanically alloyed with yttria and Hf powders. The mechanically alloyed powder included only the supersaturated solid solution γ phase without γ′ and yttria provided by severe plastic deformation, while after the 3-step aging, the γ′ phase was precipitated due to the partitioning of Al and Ta to the γ′ and Co, Cr, Re, W, and Mo to the γ phase. Mechanical alloying modified the morphology of γ′ to the new coherent γ–γ′ nanoscale lamellar structure to minimize the elastic strain energy of the precipitation, which yielded a low lattice misfit of 0.16% at high temperature. The γ′ lamellae aligned preferentially along the elastically soft [100] direction. Also, the precipitated oxide particles were refined in the γ phase by adding Hf from large incoherent YAlO{sub 3} to fine semi-coherent Y{sub 2}Hf{sub 2}O{sub 7} oxide particles with the average size of 7 nm and low interparticle spacing of 76 nm. - Highlights: • A new Ni-base ODS superalloy powder was produced by mechanical alloying. • The nanoscale γ–γ′ lamellar structure was precipitated after the aging treatment. • Fine semi-coherent Y{sub 2}Hf{sub 2}O{sub 7} oxide particles were precipitated by addition of Hf.

  12. Sn-Sb-Se based binary and ternary alloys for phase change memory applications

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Kyung-Min

    2008-10-28

    In this work, the effect of replacing Ge by Sn and Te by Se was studied for a systematic understanding and prediction of new potential candidates for phase change random access memories applications. The temperature dependence of the electrical/structural properties and crystallization kinetics of the Sn-Se based binary and Sn-Sb-Se based ternary alloys were determined and compared with those of the GeTe and Ge-Sb-Te system. The temperature dependence of electrical and structural properties were investigated by van der Pauw measurements, X-ray diffraction, X-ray reflectometry. By varying the heating rate, the Kissinger analysis has been used to determine the combined activation barrier for crystallization. To screen the kinetics of crystallization, a static laser tester was employed. In case of binary alloys of the type Sn{sub x}Se{sub 1-x}, the most interesting candidate is SnSe{sub 2} since it crystallizes into a single crystalline phase and has high electrical contrast and reasonably high activation energy for crystallization. In addition, the SnSe{sub 2}-Sb{sub 2}Se{sub 3} pseudobinary alloy system also might be sufficient for data retention due to their higher transition temperature and activation energy for crystallization in comparison to GeTe-Sb{sub 2}Te{sub 3} system. Furthermore, SnSe{sub 2}-Sb{sub 2}Se{sub 3} pseudobinary alloys have a higher crystalline resistivity. The desired rapid crystallization speed can be obtained for Sn{sub 1}Sb{sub 2}Se{sub 5} and Sn{sub 2}Sb{sub 2}Se{sub 7} alloys. (orig.)

  13. Tantalum-based multilayer coating on cobalt alloys in total hip and knee replacement

    International Nuclear Information System (INIS)

    Cobalt–chromium–molybdenum (CoCrMo) alloys are widely used in total hip and knee joint replacement, due to high mechanical properties and resistance to wear and corrosion. They are able to form efficient artificial joints by means of coupling metal-on-polymer or metal-on-metal contacts. However, a high concentration of stress and direct friction between surfaces leads to the formation of polyethylene wear debris and the release of toxic metal ions into the human body, limiting, as a consequence, the lifetime of implants. The aim of this research is a surface modification of CoCrMo alloys in order to improve their biocompatibility and to decrease the release of metal ions and polyethylene debris. Thermal treatment in molten salts was the process employed for the deposition of tantalum-enriched coating. Tantalum and its compounds are considered biocompatible materials with low ion release and high corrosion resistance. Three different CoCrMo alloys were processed as substrates. An adherent coating of about 1 μm of thickness, with a multilayer structure consisting of two tantalum carbides and metallic tantalum was deposited. The substrates and modified layers were characterized by means of structural, chemical and morphological analysis. Moreover nanoindentation, scratch and tribological tests were carried out in order to evaluate the mechanical behavior of the substrates and coating. The hardness of the coated samples increases more than double than the untreated alloys meanwhile the presence of the coating reduced the wear volume and rate of about one order of magnitude. - Highlights: ► Thermal treatment in molten salts deposits a Ta-based coating on Co-based alloys. ► Coating is composed by one or two tantalum carbides and/or metallic tantalum. ► The coating structure depends on thermal temperature and substrates carbon content. ► Coating is able to enhance biocompatibility, wear resistance and hardness.

  14. Novel bioactive Co-based alloy/FA nanocomposite for dental applications

    Directory of Open Access Journals (Sweden)

    Mohammadhossein Fathi

    2012-01-01

    Full Text Available Background: Dental cobalt base alloys are biocompatible dental materials and have been widely used in dentistry. However, metals are bioinert and may not present bioactivity in human body. Bioactivity is the especial ability to interact with human body and make a bonding to soft and hard tissues. The aim of the present research was fabrication and bioactivity evaluation of novel cobalt alloy/Fluorapatite nanocomposite (CoA/FaNC with different amounts of Fluorapatite (FA nanopowder. Materials and Methods: Co-Cr-Mo alloy (ASTM F75 powder was prepared and mixed in a planetary ball mill with different amounts of FA nanopowders (10, 15, 20% wt. Prepared composite powders were cold pressed and sintered at 1100°C for 4 h. X-ray diffraction (XRD, scanning electron microscopy and transition electron microscopy techniques were used for phase analysis, crystallite size determination of FA and also for phase analysis and evaluation of particle distribution of composites. Bioactivity behavior of prepared nanocomposites was evaluated in simulated body fluid (SBF for 1 up to 28 days. Results: Results showed that nucleus of apatite were formed on the surface of the prepared CoA/FaNC during 1 up to 28 days immersion in the SBF solution. On the other hand, CoA/FaNC unlike Co-base alloy possessed bone-like apatite-formation ability. Conclusion: It was concluded that bioinert Co-Cr-Mo alloy could be successfully converted into bioactive nanocomposite by adding 10, 15, 20 wt% of FA nano particles.

  15. Stress corrosion cracking of nickel base alloys in PWR primary water

    International Nuclear Information System (INIS)

    Stress corrosion cracking (SCC) of nickel base alloys and associated weld metals in primary water is one of the major concerns for pressurized water reactors (PWR). Since the 90's, highly cold-worked stainless steels (non-sensitized) were also found to be susceptible to SCC in PWR primary water ([1], [2], [3]). In the context of the life extension of pressurized water reactors, laboratory studies are performed in order to evaluate the SCC behaviour of components made of nickel base alloys and of stainless steels. Some examples of these laboratory studies performed at CEA will be given in the talk. This presentation deals with both initiation and propagation of stress corrosion cracks. The aims of these studies is, on one hand, to obtain more data regarding initiation time or crack growth rate and, one the other hand, to improve our knowledge of the SCC mechanisms. The aim of these approaches is to model SCC and to predict components life duration. Crack growth rate (CGR) tests on Alloy 82 with and without post weld heat treatment are performed in PWR primary water (Figure 1). The heat treatment seems to be highly beneficial by decreasing the CGR. This result could be explained by the effect of thermal treatment on the grain boundary nano-scopic precipitation in Alloy 82 [4]. The susceptibility to SCC of cold worked austenitic stainless steels is also studied. It is shown that for a given cold-working procedure, SCC susceptibility increases with increasing cold-work ([2], [5]). Despite the fact that the SCC behaviour of Alloy 600 has been widely studied for many years, recent laboratory experiments and analysis ([6], [7], [8]) showed that oxygen diffusion is not a rate-limiting step in the SCC mechanism and that chromium diffusion in the bulk close the crack tip could be a key parameter. (authors)

  16. Tantalum-based multilayer coating on cobalt alloys in total hip and knee replacement

    Energy Technology Data Exchange (ETDEWEB)

    Balagna, C., E-mail: cristina.balagna@polito.it [Institute of Materials Engineering and Physics, Applied Science and Technology Department, Politecnico di Torino, Corso Duca degli Abruzzi 24,10129 Torino (Italy); Faga, M.G. [Istituto di Scienza e Tecnologia dei Materiali Ceramici, Consiglio Nazionale delle Ricerche, Strada delle Cacce 73, 10135 Torino (Italy); Spriano, S. [Institute of Materials Engineering and Physics, Applied Science and Technology Department, Politecnico di Torino, Corso Duca degli Abruzzi 24,10129 Torino (Italy)

    2012-05-01

    Cobalt-chromium-molybdenum (CoCrMo) alloys are widely used in total hip and knee joint replacement, due to high mechanical properties and resistance to wear and corrosion. They are able to form efficient artificial joints by means of coupling metal-on-polymer or metal-on-metal contacts. However, a high concentration of stress and direct friction between surfaces leads to the formation of polyethylene wear debris and the release of toxic metal ions into the human body, limiting, as a consequence, the lifetime of implants. The aim of this research is a surface modification of CoCrMo alloys in order to improve their biocompatibility and to decrease the release of metal ions and polyethylene debris. Thermal treatment in molten salts was the process employed for the deposition of tantalum-enriched coating. Tantalum and its compounds are considered biocompatible materials with low ion release and high corrosion resistance. Three different CoCrMo alloys were processed as substrates. An adherent coating of about 1 {mu}m of thickness, with a multilayer structure consisting of two tantalum carbides and metallic tantalum was deposited. The substrates and modified layers were characterized by means of structural, chemical and morphological analysis. Moreover nanoindentation, scratch and tribological tests were carried out in order to evaluate the mechanical behavior of the substrates and coating. The hardness of the coated samples increases more than double than the untreated alloys meanwhile the presence of the coating reduced the wear volume and rate of about one order of magnitude. - Highlights: Black-Right-Pointing-Pointer Thermal treatment in molten salts deposits a Ta-based coating on Co-based alloys. Black-Right-Pointing-Pointer Coating is composed by one or two tantalum carbides and/or metallic tantalum. Black-Right-Pointing-Pointer The coating structure depends on thermal temperature and substrates carbon content. Black-Right-Pointing-Pointer Coating is able to

  17. X-ray residual stress measurement on weld metal of nickel based alloy

    International Nuclear Information System (INIS)

    Residual stress on the weld metal of nickel based alloy was evaluated through x-ray diffraction and metallurgical study of the microstructure. Weld metal specimens were prepared from Alloy182 (JIS DNiCrFe-3) and Alloy132 (JIS DNiCrFe-1J) deposited on a steel plate. X-ray diffraction results show a strong [100] preferred orientation nearly normal to the surface of the weld metal. Crystallographic consideration predicts that dominant 311 diffractions appear around 25.2 and 72.5 degrees of ψ angle. For each diffraction, the peak shift was measured at the ψ angle showing the maximum diffraction intensity, using the side-inclination method (ψ-goniometer method) with a Mn x-ray tube and a PSPC (position sensitive proportional counter). The residual stress was determined by the peak shifts according to the two tilt method. The x-ray stress constant, K, on Alloy182 was determined experimentally. The depth profile of the residual stress was measured on the ground specimens with and without laser peening. Tensile residual stress due to the grinding work is observed in the surface layer of the unpeened specimen; however it changes to compressive after laser peening. The overall behavior of the depth profile of laser peened material agrees well with that of Alloy600 base metal measured in the previous studies, where the compressive residual stress with several hundred MPa at the surface gradually decreases and reaches to around 0 MPa at the depth of about 1 mm. (author)

  18. Biocorrosion behavior and cell viability of adhesive polymer coated magnesium based alloys for medical implants

    International Nuclear Information System (INIS)

    Highlights: ► The corrosion behavior of magnesium for orthopedic applications is extremely poor. ► The solvent (DCM, THF and DMF) had a strong effect on the coatings performance. ► Mg bar alloy coated with PVAc/DCM layers provided an excellent bonding strength. ► Treated samples indicated significant damping for the degradation rate. ► Cytocompatibility on MC3T3 cells of the PVAc/DCM samples revealed a good behavior. - Abstract: The present study was ultimately aimed to design novel adhesive biodegradable polymer, poly(vinyl acetate) (PVAc), coatings onto Mg based alloys by the dip-coating technique in order to control the degradation rate and enhance the biocompatibility of magnesium alloys. The influence of various solvents on PVAc surface topography and their protection of Mg alloys were dramatically studied in vitro. Electrochemical polarization, degradation, and PVAc film cytocompatibility were also tested. Our results showed that the solvent had a significant effect on coating quality. PVAc/dichloromethane solution showed a porous structure and solution concentration could control the porous size. The coatings prepared using tetrahydrofuran and dimethylformamide solvents are exceptional in their ability to generate porous morphology even at low polymer concentration. In general, the corrosion performance appears to be different on different PVAc–solvent system. Immersion tests illustrated that the porous morphology on PVAc stabilized corrosion rates. A uniform corrosion attack in artificial simulation body fluid was also exhibited. The cytocompatibility of osteoblast cells (MC3T3) revealed high adherence, proliferation, and survival on the porous structure of PVAc coated Mg alloy, which was not observed for the uncoated samples. This novel PVAc coating is a promising candidate for biodegradable implant materials, which might widen the use of Mg based implants.

  19. Biocorrosion behavior and cell viability of adhesive polymer coated magnesium based alloys for medical implants

    Energy Technology Data Exchange (ETDEWEB)

    Abdal-hay, Abdalla [Departmentt of Bionano System Engineering, College of Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Department of Mechanical Design Engineering, Advanced wind power system research institute, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Dewidar, Montasser [Department of Materials and Mechanical Design, Faculty of Energy Engineering, South Valley University, Aswan (Egypt); Lim, Jae Kyoo, E-mail: jklim@jbnu.ac.kr [Department of Mechanical Design Engineering, Advanced wind power system research institute, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer The corrosion behavior of magnesium for orthopedic applications is extremely poor. Black-Right-Pointing-Pointer The solvent (DCM, THF and DMF) had a strong effect on the coatings performance. Black-Right-Pointing-Pointer Mg bar alloy coated with PVAc/DCM layers provided an excellent bonding strength. Black-Right-Pointing-Pointer Treated samples indicated significant damping for the degradation rate. Black-Right-Pointing-Pointer Cytocompatibility on MC3T3 cells of the PVAc/DCM samples revealed a good behavior. - Abstract: The present study was ultimately aimed to design novel adhesive biodegradable polymer, poly(vinyl acetate) (PVAc), coatings onto Mg based alloys by the dip-coating technique in order to control the degradation rate and enhance the biocompatibility of magnesium alloys. The influence of various solvents on PVAc surface topography and their protection of Mg alloys were dramatically studied in vitro. Electrochemical polarization, degradation, and PVAc film cytocompatibility were also tested. Our results showed that the solvent had a significant effect on coating quality. PVAc/dichloromethane solution showed a porous structure and solution concentration could control the porous size. The coatings prepared using tetrahydrofuran and dimethylformamide solvents are exceptional in their ability to generate porous morphology even at low polymer concentration. In general, the corrosion performance appears to be different on different PVAc-solvent system. Immersion tests illustrated that the porous morphology on PVAc stabilized corrosion rates. A uniform corrosion attack in artificial simulation body fluid was also exhibited. The cytocompatibility of osteoblast cells (MC3T3) revealed high adherence, proliferation, and survival on the porous structure of PVAc coated Mg alloy, which was not observed for the uncoated samples. This novel PVAc coating is a promising candidate for biodegradable implant materials, which might

  20. Chemical extraction of refractory inclusions from iron- and nickel-base alloys

    International Nuclear Information System (INIS)

    Most iron- and nickel-base alloys contain certain refractory inclusions, which affect the physical properties of the alloy. Carbides are the predominant inclusion, but oxides, nitrides, sulfides, borides, and phosphides may also be present. A chemical extraction has been developed which effectively separates these inclusions from the matrix without the application of an external potential. The refractory inclusions are quantitatively extracted by chemical dissolution of the matrix at 250C with a solution 0.9 M in copper(II) potassium chloride and hydrochloric acid. The reagent also contains 0.1 M tartaric acid to avoid contamination of the insoluble inclusion with matrix hydrolysis products. The chemical extractant is identified as the Berzelius reagent. The solvent is a general reagent for the isolation of most refractory phases: carbides, nitrides, phosphides, sulfides, oxides, and certain intermetallic compounds. The reagent dissolves alloys which are predominantly aluminum, cobalt, copper, iron, nickel, or zinc. The separation requires up to 24 hours to dissolve the alloys' matrix

  1. Growth Stresses in Thermally Grown Oxides on Nickel-Based Single-Crystal Alloys

    Science.gov (United States)

    Rettberg, Luke H.; Laux, Britta; He, Ming Y.; Hovis, David; Heuer, Arthur H.; Pollock, Tresa M.

    2016-03-01

    Growth stresses that develop in α-Al2O3 scale that form during isothermal oxidation of three Ni-based single crystal alloys have been studied to elucidate their role in coating and substrate degradation at elevated temperatures. Piezospectroscopy measurements at room temperature indicate large room temperature compressive stresses in the oxides formed at 1255 K or 1366 K (982 °C or 1093 °C) on the alloys, ranging from a high of 4.8 GPa for René N4 at 1366 K (1093 °C) to a low of 3.8 GPa for René N5 at 1255 K (982 °C). Finite element modeling of each of these systems to account for differences in coefficients of thermal expansion of the oxide and substrate indicates growth strains in the range from 0.21 to 0.44 pct at the oxidation temperature, which is an order of magnitude higher than the growth strains measured in the oxides on intermetallic coatings that are typically applied to these superalloys. The magnitudes of the growth strains do not scale with the parabolic oxidation rate constants measured for the alloys. Significant spatial inhomogeneities in the growth stresses were observed, due to (i) the presence of dendritic segregation and (ii) large carbides in the material that locally disrupts the structure of the oxide scale. The implications of these observations for failure during cyclic oxidation, fatigue cycling, and alloy design are considered.

  2. Airfoil-based piezoelectric energy harvesting by exploiting the pseudoelastic hysteresis of shape memory alloy springs

    Science.gov (United States)

    de Sousa, Vagner Candido; De Marqui Junior, Carlos

    2015-12-01

    The modeling and analysis of an electromechanically coupled typical aeroelastic section with shape memory alloy springs for wind energy harvesting is addressed in this paper. An airfoil with two-degrees-of-freedom, namely pitch and plunge, is considered and piezoelectric coupling is added to the plunge degree-of-freedom. A load resistance is assumed in the electrical domain of the problem in order to estimate the electrical power output. Shape memory alloy coil springs are modeled in the pitch degree-of-freedom of the typical section. A nickel-titanium alloy that exhibits pseudoelasticity at room temperature is assumed. The constitutive model for the shape memory alloy is based on classical phenomenological models. The unsteady aerodynamic loads are obtained by Jones’ approximation to Wagner’s indicial function. The resulting nonlinear electroaeroelastic model is cast into a state-space representation and solved with a Runge-Kutta method. The effects of preload values of the shape memory springs and resistive power generation on the aeroelastic behavior of the wind energy harvester are investigated at the flutter boundary and in a post-flutter regime. The nonlinear kinetics of the austenite-to-martensite phase transformation changes the typical linear flutter behavior to stable limit-cycle oscillations over a range of airflow speeds. Such nonlinear aeroelastic behavior introduced by the hysteretic behavior of the SMA springs provides an important source of persistent electrical power.

  3. Stress corrosion cracking of Ni-base and Ti alloys under controlled potential

    International Nuclear Information System (INIS)

    Susceptibility to stress corrosion cracking (SCC) of alloy C-22 and Ti Gr-12, two candidate alloys for the inner-container of the multi-barrier nuclear waste package, was evaluated by using the slow-strain-rate (SSR) test technique in a deaerated acidic brine (pH ∼ 2.70) at 90 C. The strain rate used was 3.3 x 10-6 sec-1. Prior to being tested in the acidic brine, specimens of each alloy were pulled inside the test chamber in the dry condition at room temperature (RT). Then specimens were exposed to the test solution while being strained under different controlled electrochemical potentials. The magnitude of the controlled potential was selected based on the corrosion potential measured in the test solution prior to straining of the specimen. Results indicate that, for Ti Gr-12, the times to failure were significantly shorter compared to those for alloy C-22. Furthermore, Ti Gr-12 showed reduced ductility in terms of percent reduction in area and true fracture stress, as the controlled potential became more cathodic. Results also indicate that the time-to-failure and percent elongation reached the minimum values when Ti Gr-12 was tested under impressed potential of -1162 mV. Finally, metallographic examination was performed to evaluate the primary fracture, and the secondary cracking, if any, along the gage section of the broken tensile specimen

  4. Stress corrosion cracking mechanisms of Fe-based alloys in hydrogenated hot water

    International Nuclear Information System (INIS)

    It is generally accepted that carbon steel resists Stress Corrosion Cracking (SCC) in hot water provided the oxygen content is low enough; however, isolated cracking events have occurred, apparently in fully reducing conditions, and these may or may not be true SCC. There are also occasional reports of SCC of austenitic stainless steel in reducing conditions where cold work may play a critical role. SCC though originally seen in sensitized material at oxidizing potentials persists to low potentials and in cold-worked but unsensitized material. We suspect from the literature that alloying with Ni introduces a susceptibility to SCC in reducing hot water as well as in caustic solution. Our hypothesis is that Ni causes SCC, and Cr retards it; so stainless steel has just enough Cr to protect against SCC under most conditions. We are examining this using model Fe-based materials and environments designed to separate the effects of different parameters. Early results suggest that Fe-Ni alloys and austenitic SS both undergo de-alloying and SCC in reducing caustic solutions. It is hypothesised that if these alloys are indeed susceptible to dealloying (and hence to SCC) in this environment then we can reasonably project that their behaviour in reducing, hot pure water may be similar. This is pertinent to understanding recent failures in high temperature, high pressure aqueous systems. As a first step we have investigated the surface reactions that occur in caustic solutions and in hot water. (author)

  5. Creep Rupture Properties for Base and Weld Metals of Alloy 617

    International Nuclear Information System (INIS)

    The allowable deformation in the welds is also restricted to half the deformation permitted for the base metal, since the ductility of the welds at elevated temperatures is generally low. For a design use, the data of the tensile and creep properties for Alloy 617 WM should be sufficiently provided, and in particular, to develop a design code of Alloy 617 WM. However, the data for the WM are very rare and limited until now, although the data for the BM are available in the ASME draft code case, which was suspended at the end of the 1980s owing to a lack of support and interes. In this report, the creep data for Alloy 617 WM, which was fabricated by a gas tungsten arc welding (GTAW) procedure, were obtained by a series of creep tests at 800 .deg. C, and the creep properties of the WM were compared with those of the BM. The high-temperature creep properties for Alloy 617 WM, fabricated by a gas tungsten arc welding (GTAW) procedure, were investigated by a series of creep tests with different stress levels at 800 .deg. C, and the creep test data for the WM were compared with those of the BM. From the results, it was found that the WM had a slightly longer creep rupture life and lower creep rate than the BM, and a particularly lower rupture elongation. The lower creep rate in the WM was due to the lower rupture elongation than the BM

  6. De Haas-van Alphen effect study of electronic structures of niobium-based molybdenum alloys

    International Nuclear Information System (INIS)

    The electronic structures of dilute niobium-based molybdenum alloys have been studied by using the de Haas-van Alphen effect. The rate of increase of the Dingle temperature (ΔTsub(D)* on alloying is found to be fairly small compared with that of noble-metal alloys and to be anisotropic over the Fermi surfaces, that is, 3 K (at% Mo)-1 for ν oscillations arising from the ellipsoids, and 7 K (at% Mo)-1 for α and eta oscillations arising from the jungle gym. The change in frequency of the ν3456 oscillation is about 2/3 that predicted by the rigid band model. Applying the partial-wave analysis to these experimental facts, the following results are obtained. (i) T/e d wave phase shift dominates over s, p and f wave phase shifts in this alloy system and the anisotropy in ΔTsub(D)* results from the anisotropy in the amount of d component of the wavefunction over the Fermi surfaces. (ii) The non-rigid band-like behaviour of the ν3456 oscillation arises from the same origin as ΔTsub(D)*. (iii) The significantly small ΔTsub(D)* found in the present experiment is related to a small electron group velocity on the Fermi surfaces in niobium. (author)

  7. Effects in Mg-Zn-based alloys strengthened by quasicrystalline phase

    Science.gov (United States)

    Vlček, M.; Čížek, J.; Lukáč, F.; Melikhova, O.; Hruška, P.; Procházka, I.; Vlach, M.; Stulíková, I.; Smola, B.; Jäger, A.

    2016-01-01

    Magnesium Mg-based alloys are promising lightweight structural materials for automotive, aerospace and biomedical applications. Recently Mg-Zn-Y system attracted a great attention due to a stable icosahedral phase (I-phase) with quasicrystalline structure which is formed in these alloys. Positron lifetime spectroscopy and in situ synchrotron X-ray diffraction were used to study thermal stability of I-phase and precipitation effects in Mg-Zn-Y and Mg- Zn-Al alloys. All alloys containing quasicrystalline I-phase exhibit misfit defects characterized by positron lifetime of ∼ 300 ps. These defects are associated with the interfaces between I- phase particles and Mg matrix. The quasicrystalline I-phase particles were found to be stable up to temperatures as high as ∼ 370°C. The W-phase is more stable and melts at ∼ 420°C. Concentration of defects associated with I-phase decreases after annealing at temperatures above ∼ 300°C.

  8. A refined energy-based model for friction stir processing of AlZn-Mg alloy

    Directory of Open Access Journals (Sweden)

    P. K. Mandal

    2016-01-01

    Full Text Available Friction stir processing (FSP is a promising solid state surface modification technique. Also, considered as an innovative technique that the FSPwas employed to modify the surface layer of aluminium alloy. The FSP passes of only two passes were applied on aluminium alloy samples. A rotating tool with a pin and shoulder is inserted into a single piece of material and results in significant microstructural changes in the processed zone, due to intense plastic deformation. It has been proved to be an effective way to refine the microstructure of aluminium alloys, and thereby improve the mechanical properties. In procedural phenomenon there are different parameters adjustment have been worked out to refine microstructure and several properties characterised to TEM, SEM, FESEM and mechanical properties. In this study, a refined energy based model that estimates the energy generated due to friction and plastic deformation is presented with the help ofexperimental and theoretical results available in many literatures. The model is applied to 7xxx series of aluminium alloys.

  9. High Temperature Heat Capacity of Alloy D9 Using Drop Calorimetry Based Enthalpy Increment Measurements

    Science.gov (United States)

    Banerjee, Aritra; Raju, S.; Divakar, R.; Mohandas, E.

    2007-02-01

    Alloy D9 is a void-swelling resistant nuclear grade austenitic stainless steel (SS) based on AISI type 316-SS in which titanium constitutes an added predetermined alloying composition. In the present study, the high-temperature enthalpy values of alloy D9 with three different titanium-to-carbon mass percent ratios, namely Ti/C = 4, 6, and 8, have been measured using inverse drop calorimetry in the temperature range from 295 to 1323 K. It is found that within the level of experimental uncertainty, the enthalpy values are independent of the Ti-C mass ratio. The temperature dependence of the isobaric specific heat C P is obtained by a linear regression of the measured enthalpy data. The measured C P data for alloy D9 may be represented by the following best-fit expression: C_P(J \\cdot kg^{-1}\\cdot K^{-1})= 431 + 17.7 × 10^{-2}T + 8.72 × 10^{-5}/T^2. It is found that the measured enthalpy and specific heat values exhibit good agreement with reported data on 316 and other related austenitic stainless steels.

  10. Corrosion and Sliding Properties of the Nickel-Based Alloys for the Valve Seats Application

    International Nuclear Information System (INIS)

    This paper describes the experiments of the corrosion and the sliding tests of the nickel-based alloys for the gate valve seating materials used at high pressure and temperature. The general corrosion rates and IGC susceptibility are tested in pressurized water at 533 K and 575 k and in Strauss test solution. The sliding tests have been done in pressurized water at 293 k, 473 K and 573 k. The alloys containing above 10% chromium may have the anti-corrosion properties that could be applied to the valve seats for the power plants. The good sliding performance and the good pressure tightness are obtained when the disc specimens that have hardness 500 to 600 Hv combined with the seat specimens that have hardness 250 to 410 Hv containing about 40 percent of iron. The large size gate valves sliding tests have certified the test results. The anti-wear properties of the seat alloy and the anti-IGC susceptibility of the disc alloy could be improved by the addition of silicon and niobium, respectively

  11. High temperature oxidation and electrochemical investigations on nickel-base alloys

    International Nuclear Information System (INIS)

    This study examined high-temperature oxidation behavior of different Ni-base alloys. In addition, electrochemical characterization of the alloy's corrosion behavior was carried out, including comparison of the properties of native passive films grown at room temperature and high temperature oxide scales. PWA 1483 (single-crystalline Ni-base superalloy) and model alloys Ni-Cr-X (where X is either Co or Al) were oxidized at 800 and 900 C in air for different time periods. The superalloy showed the best oxidation behavior at both temperatures, which might be due to the fact that the oxidation growth function is subparabolic for the model alloys and parabolic for the superalloy at 800 C. At higher temperatures, changes in the kinetics are induced, as the oxides grow faster, thus only PWA 1483 growth follows the parabolic law. Different scales in a typical sandwich form were detected, with the inner layer comprised of mostly Cr2O3, the middle layer was mixture of different oxides and spinels, depending on the alloying elements, and the oxide at the interface oxygen/oxide was found to be NiO. The influence of sample preparation could also be shown, as rougher surfaces change the oxidation kinetics from parabolic and subparabolic for polished samples to linear. The influence of moisture on the oxidation behavior of the 2nd generation single crystal Ni-base superalloys (PWA 1484, PWA 1487, CMSX 4, Rene N5 and Rene N5+) was studied at 1000 C after 100 h oxidation period. It was found that the moisture increased the oxidation rate and mostly the transient oxides growth rate. The water vapor content in air also influenced the behavior of these alloys, as they showed a higher mass gain in air + 30% water vapor than in air + 10% water vapor. The alloys PWA 1484 and CMSX 4 showed respectively the worst and best behavior in all the studied atmospheres. The addition of reactive elements, such as Yttrium, Hafnium and Lanthanum is likely to enhance the oxidation behavior of PWA 1487

  12. Urinary levels of nickel and chromium associated with dental restoration by nickel-chromium based alloys

    Institute of Scientific and Technical Information of China (English)

    Bo Chen; Gang Xia; Xin-Ming Cao; Jue Wang; Bi-Yao Xu; Pu Huang; Yue Chen; Qing-Wu Jiang

    2013-01-01

    This paper aims to investigate if the dental restoration of nickel-chromium based alloy (Ni-Cr) leads to the enhanced excretions of Ni and Cr in urine. Seven hundred and ninety-five patients in a dental hospital had single or multiple Ni-Cr alloy restoration recently and 198 controls were recruited to collect information on dental restoration by questionnaire and clinical examination. Urinary concentrations of Ni and Cr from each subject were measure by graphite furnace atomic absorption spectrometry. Compared to the control group, the urinary level of Ni was significantly higher in the patient group of 〈 1 month of the restoration duration, among which higher Ni excretions were found in those with either a higher number of teeth replaced by dental alloys or a higher index of metal crown not covered with the porcelain. Urinary levels of Cr were significantly higher in the three patient groups of 〈1, 1 to 〈3 and 3 to 〈6 months, especially in those with a higher metal crown exposure index. Linear curve estimations showed better relationships between urinary Ni and Cr in patients within 6-month groups. Our data suggested significant increased excretions of urinary Ni and Cr after dental restoration. Potential short- and long-term effects of Ni-Cr alloy restoration need to be investigated.

  13. Various transformation modes observed in two-phase γ + α2 TiAl-based alloys

    International Nuclear Information System (INIS)

    This paper deals with various transformation modes taking place in two-phase γ+α2 TiAl-based alloys. These transformation modes are: (1) decomposition of the α phase leading to the precipitation of the γ lamellae (α→α+γ), (2) ordering reaction of the α phase (α→α2), (3) massive transformation (α→γ), (4) formation of monolithic γ grains and (5) discontinuous coarsening. By analyzing their kinetics, three types of competitions were identified between these transformation modes: (1) vs. (2), (2) vs. (3) and (4) vs. (5). The occurrence of (2) or (3) and (4) or (5) in binary alloys is strongly dependent on the alloy composition. Therefore, by examining these two competitions in transformation modes, it is possible to evaluate the influence of small additions of ternary and quaternary elements on the response to heat treatments without a precise knowledge of the phase diagrammes of complex alloy systems. Another important finding of the present study is related to the formation of the γ phase from the α phase; this can occur through either lamellar precipitation (α → α2 → α2+γ, or α → α+γ → α2+γ) or massive reaction (α → γ). The mechanisms involved during these two transformations are investigated and some of the key issues are discussed in the present paper. (orig.)

  14. Corrosion of ferritic-martensitic steels and nickel-based alloys in supercritical water

    Science.gov (United States)

    Ren, Xiaowei

    The corrosion behavior of ferritic/martensitic (F/M) steels and Ni-based alloys in supercritical water (SCW) has been studied due to their potential applications in future nuclear reactor systems, fossil fuel power plants and waste treatment processes. 9˜12% chromium ferritic/martensitic steels exhibit good radiation resistance and stress corrosion cracking resistance. Ni-based alloys with an austenitic face-centered cubic (FCC) structure are designed to retain good mechanical strength and corrosion/oxidation resistance at elevated temperatures. Corrosion tests were carried out at three temperatures, 360°C, 500°C and 600°C, with two dissolved oxygen contents, 25 ppb and 2 ppm for up to 3000 hours. Alloys modified by grain refinement and reactive element addition were also investigated to determine their ability to improve the corrosion resistance in SCW. A duplex oxide structure was observed in the F/M steels after exposure to 25 ppb oxygen SCW, including an outer oxide layer with columnar magnetite grains and an inner oxide layer constituted of a mixture of spinel and ferrite phases in an equiaxed grain structure. An additional outermost hematite layer formed in the SCW-exposed samples when the oxygen content was increased to 2 ppm. Weight gain in the F/M steels increased with exposure temperatures and times, and followed parabolic growth kinetics in most of the samples. In Ni-based alloys after exposure to SCW, general corrosion and pitting corrosion were observed, and intergranular corrosion was found when exposed at 600°C due to formation of a local healing layer. The general oxide structure on the Ni-based alloys was characterized as NiO/Spinel/(CrxFe 1-x)2O3/(Fe,Ni). No change in oxidation mechanism was observed in crossing the critical point despite the large change in water properties. Corrosion resistance of the F/M steels was significantly improved by plasma-based yttrium surface treatment because of restrained outward diffusion of iron by the

  15. Influence of the pulsed plasma treatment on the corrosion resistance of the low-alloy steel plated by Ni-based alloy

    Science.gov (United States)

    Dzhumaev, P.; Yakushin, V.; Kalin, B.; Polsky, V.; Yurlova, M.

    2016-04-01

    This paper presents investigation results of the influence of high temperature pulsed plasma flows (HTPPF) treatment on the corrosion resistance of low-alloy steel 0.2C-Cr-Mn- Ni-Mo cladded by the rapidly quenched nickel-based alloy. A technique that allows obtaining a defect-free clad layer with a good adhesion to the substrate was developed. It is shown that the preliminary treatment of steel samples by nitrogen plasma flows significantly increases their corrosion resistance in the conditions of intergranular corrosion test in a water solution of sulfuric acid. A change of the corrosion mechanism of the clad layer from intergranular to uniform corrosion was observed as a result of sub-microcrystalline structure formation and homogeneous distribution of alloying elements in the plasma treated surface layer thus leading to the significant increase of the corrosion resistance.

  16. Translating VDM to Alloy

    DEFF Research Database (Denmark)

    Lausdahl, Kenneth

    2013-01-01

    specifications. However, to take advantage of the automated analysis of Alloy, the model-oriented VDM specifications must be translated into a constraint-based Alloy specifications. We describe how a sub- set of VDM can be translated into Alloy and how assertions can be expressed in VDM and checked by the Alloy...

  17. Metallurgical characterizations of Fe–Cr–Ni–Zr base alloys developed for geological disposal of radioactive hulls

    International Nuclear Information System (INIS)

    Highlights: ► Immobilization of Zr-rich radioactive metallic wastes via alloy melting route. ► First detail report on metallurgical characterizations of Fe–Cr–Ni–Zr alloys. ► Identification of suitable base alloy composition. - Abstract: Alloy melting route is currently being considered for radioactive hulls immobilization. Towards this, wide range of alloys, belonging to Zirconium–Iron binary and Zirconium–Stainless steel pseudo-binary systems have been prepared through vacuum arc melting route. Detail microstructural characterization and quantitative phase analyses of these alloys along with interaction study between Zirconium and Stainless steel coupons at elevated temperatures identify Zr(Fe,Cr)2, Zr(Fe,Cr), Zr2(Fe,Cr), Zr3(Fe,Ni), Zr3(Fe,Cr), Zr3(Fe,Cr,Ni), β-Zr and α-Zr as the most commonly occurring phases within the system for Zirconium rich bulk compositions. Nano-indentation studies found Zr(Fe,Cr)2 and Zr(Fe,Cr) as extremely hard, Zr3(Fe,Ni) as moderately ductile and β-Zr, Zr2(Fe,Cr) as most ductile ones among the phases present. Steam oxidation studies of the alloys, based on weight gain/loss procedure and microstructural characterization of the mixed oxide layers, suggest that each of the alloys responded to the corrosive environment differently. Fe2O3, NiFe2O4, NiO, monoclinic ZrO2 and tetragonal ZrO2 are found to be most common constituents of the oxide layers developed on the alloys. Integrating the microstructural, mechanical and corrosion properties, ZrFeCrNi3 (Zr: 84.00, Fe: 11.20, Cr: 3.20, Ni: 1.60, in wt.%) is identified as the acceptable base alloy for disposal of radioactive hulls.

  18. Microstructural evolutions and mechanical behaviour of the nickel based alloys 617 and 230 at high temperature

    International Nuclear Information System (INIS)

    High Temperature Reactors (HTR), is one of the innovative nuclear reactor designed to be inherently safer than previous generation and to produce minimal waste. The most critical metallic component in that type of reactor is the Intermediate Heat exchanger (IHX). The constraints imposed by the conception and the severe operational conditions (high temperature of 850 C to 950 C, lifetime of 20,000 h) have guided the IHX material selection toward two solid solution nickel base alloys, the Inconel 617 and the Haynes 230. Inconel 617 is the primary candidate alloy thanks to its good high temperature mechanical and corrosion properties and the large data base developed in previous programs. However, its high cobalt content has to be considered as an issue (nuclear activation). The more recent alloy Haynes 230, in which most of the cobalt has been replaced by tungsten, present characteristics similar to the 617 alloy. The objective of this thesis is to study the high temperature mechanical behaviour of both alloys in relation with their microstructural evolutions. The as received microstructural observations have revealed primary carbides (M6C). Most of this precipitates are evenly distributed in the materials. Few M23C6 secondary carbides are observed in both alloys in the as received state. Thermal ageing treatments at 850 C lead to an important M23C6 precipitation on slip lines and at grain boundaries. The size of this carbides increases and their number decreases with increasing ageing duration. The intragranular precipitation of secondary carbides at 950 C is more limited and the intergranular evolution more important than at 850 C. The microstructural observations and the hardness evolution of both alloys show that the main microstructural evolutions occur before 1,000 h at both studied temperatures. The mechanical properties of the Inconel 617 and the Haynes 230 have been studied using tensile, creep, fatigue and relaxation-fatigue tests. Particularly, the

  19. AB INITIO Modeling of Thermomechanical Properties of Mo-Based Alloys for Fossil Energy Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Ching, Wai-Yim

    2013-12-31

    In this final scientific/technical report covering the period of 3.5 years started on July 1, 2011, we report the accomplishments on the study of thermo-mechanical properties of Mo-based intermetallic compounds under NETL support. These include computational method development, physical properties investigation of Mo-based compounds and alloys. The main focus is on the mechanical and thermo mechanical properties at high temperature since these are the most crucial properties for their potential applications. In particular, recent development of applying ab initio molecular dynamic (AIMD) simulations to the T1 (Mo{sub 5}Si{sub 3}) and T2 (Mo{sub 5}SiB{sub 2}) phases are highlighted for alloy design in further improving their properties.

  20. A set of microstructure-based constitutive equations in hot forming of a titanium alloy

    Institute of Scientific and Technical Information of China (English)

    Xiaoli Li; Miaoquan Li

    2006-01-01

    A physical model of microstructure evolution including dislocation density rate and grain growth rate was established based on the deformation mechanism for the hot forming of a class of two-phase titanium alloys. Further, a set of mechanism-based constitutive equations were proposed, in which the microstructure variables such as grain size and dislocation density were taken as internal state variables for characterizing the current material state. In the set of constitutive equations, the contributions of different mechanisms and individual phase to the deformation behavior were analyzed. The present equations have been applied to describe a correlation of the flow stress with the microstructure evolution of the TC6 alloy in hot forming.