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Sample records for pb-bi eutectic alloy

  1. Microstructure Of MnBi/Bi Eutectic Alloy

    Science.gov (United States)

    Wilcox, William R.; Eisa, G. F.; Baskaran, B.; Richardson, Donald C.

    1988-01-01

    Collection of three reports describes studies of directional solidification of MnBi/Bi eutectic alloy. Two of the reports, "Influence of Convection on Lamellar Spacing of Eutectics" and "Influence of Convection on Eutectic Microstructure," establish theoretical foundation for remaining document. Reports seek to quantify effect of convection on concentration field of growing lamellar eutectic. Remaining report, "Study of Eutectic Formation," begins by continuing theoretical developments. New technique under development by one of the authors helps to reveal three-dimensional microstructures of alloys.

  2. High temperature ultrasonic transducers for imaging and measurements in a liquid Pb/Bi eutectic alloy.

    Science.gov (United States)

    Kazys, Rymantas; Voleisis, Algirdas; Sliteris, Reimondas; Mazeika, Liudas; Van Nieuwenhove, Rudi; Kupschus, Peter; Abderrahim, Hamid Aït

    2005-04-01

    In some nuclear reactors or accelerator-driven systems (ADS) the core is intended to be cooled by means of a heavy liquid metal, for example, lead-bismuth (Pb/Bi) eutectic alloy. For safety and licensing reasons, an imaging method of the interior of ADS, based on application of ultrasonic waves, has thus to be developed. This paper is devoted to description of developed various ultrasonic transducers suitable for long term imaging and measurements in the liquid Pb/Bi alloy. The results of comparative experimental investigations of the developed transducers of different designs in a liquid Pb/Bi alloy up to 450 degrees C are presented. Prototypes with different high temperature piezoelectric materials were investigated: PZT, bismuth titanate (Bi4Ti3O12), lithium niobate (LiNbO3), gallium orthophosphate (GaPO4) and aluminum nitride (A1N). For acoustic coupling with the metal alloy, it was proposed to coat the active surface of the transducers by diamond like carbon (DLC). The radiation robustness was assessed by exposing the transducers to high gamma dose rates in one of the irradiation facilities at SCK x CEN. The experimental results proved that the developed transducers are suitable for long-term operation in harsh conditions.

  3. Out-of-pile chemical compatibility of Pb-Bi eutectic alloy with graphite

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, A.K.; Bhagat, R.K.; Jarvis, T.; Majumdar, S. [Radiometallurgy Div., Bhabha Atomic Research Centre, Mumbai (India); Laik, A.; Kale, G.B. [Material Science Div., Bhabha Atomic Research Centre, Mumbai (India); Kamath, H.S. [Nuclear Fuels Group, Bhabha Atomic Research Centre, Mumbai (India)

    2006-06-15

    Lead Bismuth eutectic alloy (Pb: 55.5 wt.%, Bi: 44.5 wt.%) is a potential candidate coolant material for high-temperature reactors because of its low melting point (124 C), high thermal conductivity, heat capacity, and better neutronic properties. Out-of-pile chemical compatibility studies of this coolant with graphite (coolant channel) have been carried out by isothermal annealing of the liquid alloy in a graphite crucible at 800, 900, 1000, and 1100 C for times ranging from 100 h to 1000 h. Formation of a reaction layer is observed. The growth rate of the reaction layer follows a parabolic law. Reaction layer thicknesses of 61.3 {mu}m and 121 {mu}m are estimated from the growth rate vs. time relation after 1 year and 5 years respectively. The growth of the reaction layer is diffusion-controlled and the activation energy of the reaction is estimated to be 100 KJ/mol. (orig.)

  4. Out-of-pile chemical compatibility of Pb-Bi eutectic alloy with graphite

    International Nuclear Information System (INIS)

    Sengupta, A.K.; Bhagat, R.K.; Jarvis, T.; Majumdar, S.; Laik, A.; Kale, G.B.; Kamath, H.S.

    2006-01-01

    Lead Bismuth eutectic alloy (Pb: 55.5 wt.%, Bi: 44.5 wt.%) is a potential candidate coolant material for high-temperature reactors because of its low melting point (124 C), high thermal conductivity, heat capacity, and better neutronic properties. Out-of-pile chemical compatibility studies of this coolant with graphite (coolant channel) have been carried out by isothermal annealing of the liquid alloy in a graphite crucible at 800, 900, 1000, and 1100 C for times ranging from 100 h to 1000 h. Formation of a reaction layer is observed. The growth rate of the reaction layer follows a parabolic law. Reaction layer thicknesses of 61.3 μm and 121 μm are estimated from the growth rate vs. time relation after 1 year and 5 years respectively. The growth of the reaction layer is diffusion-controlled and the activation energy of the reaction is estimated to be 100 KJ/mol. (orig.)

  5. Investigation of corrosion resistance of 18Cr-14NNi-1.5Si austenitic steel in molten PbBi eutectic

    International Nuclear Information System (INIS)

    Rivai, A.K.; Heinzel, H.; Effendi, N.

    2013-01-01

    Full-text: The development of high corrosion resistant materials for the fuel cladding and structural materials in liquid lead-bismuth (Pb-Bi) eutectic environment especially at high temperature is a critical issue for the deployment of LFR (Lead alloy-cooled fast reactor) and ADS (Accelerator driven Transmutation System). Pb-Bi eutectic is a coolant for LFR which is one of the future nuclear reactors in the world (Generation IV reactors), and also a spallation target material and a coolant for ADS. In this study, corrosion test of an austenitic steel was done in COSTA Pb-Bi eutectic corrosion test facility at Pulsed Power and Microwave Technology, Karlsruhe Institute of Technology, Germany. The sample was an 18Cr-14Ni-1.5Si austenitic steel which has been developed in Center For Technology of Nuclear Industry Materials, Indonesian National Nuclear Energy Agency. The test was done in stagnant molten Pb-Bi eutectic at 550 degree Celsius of temperature for about 300 hours with an oxygen concentration of 1 x 10 -6 wt %. The characterization was carried out using OM (Optical Microscope), SEM-EDS (Scanning Electron Microscope and Energy Dispersive X-ray Spectroscope) and AFM (Atomic Force Microscope). The corrosion test result showed the formation of a duplex oxide layer for example an outer iron oxide layer with about 3-3.4 μm in thickness. Furthermore, there was no penetration of Pb-Bi into the bulk of the specimen because of the protection from the protective oxide layer. (author)

  6. Fusion technology for the production of PbLi eutectic alloys; Obtencion de aleaciones eutecticas PbLi mediante procesos de fusion

    Energy Technology Data Exchange (ETDEWEB)

    Barrena, M. J.; Gomez de Salazar, J. M.; Quinones, J.; Pascual, L.; Soria, A.

    2012-07-01

    The development of thermonuclear experimental reactor (ITER), whose objective is to produce energy from nuclear fusion, has raised the study of Pb-Li eutectic alloys, as they have been selected for the manufacture of test blanket modules (TBM). However, during the manufacturing process of the Pb-Li alloys, thermal conditions used result in a loss of litium element, which inhibits the formation of eutectic structures. In this work we have done fusion of pure lead and lithium, evaluating different process parameters to obtain Pb-Li (17 at. %) eutectic alloys. The alloys manufactured were characterized by DSC, SEM-EDX and microhardness tests. From these studies we noted that the used of an induction reactor and the process parameters optimized to obtain Pb-Li alloy allow for completely eutectic ingots and high chemical homogeneity and microstructural. (Author) 26 refs.

  7. Lead activity in Pb-Sb-Bi alloys

    Directory of Open Access Journals (Sweden)

    A. S. Kholkina

    2014-11-01

    Full Text Available The present work is devoted to the study of lead thermodynamic activity in the Pb-Sb-Bi alloys. The method for EMF measurements of the concentration cell: (–Pb|KCl-PbCl2¦¦KCl-PbCl2|Pb-(Sb-Bi(+ was used. The obtained concentration dependences of the galvanic cell EMF are described by linear equations. The lead activity in the ternary liquid-metal alloy demonstrates insignificant negative deviations from the behavior of ideal solutions.

  8. Behavior of steels in flowing liquid PbBi eutectic alloy at 420-600 deg. C after 4000-7200 h

    International Nuclear Information System (INIS)

    Mueller, G.; Heinzel, A.; Konys, J.; Schumacher, G.; Weisenburger, A.; Zimmermann, F.; Engelko, V.; Rusanov, A.; Markov, V.

    2004-01-01

    This paper presents the results of steel exposure up to 7200 h in flowing LBE at elevated temperatures and is a follow-up paper of that with results of an exposure of up to 2000 h. The examined AISI 316 L, 1.4970 austenitic and MANET 10Cr martensitic steels are suitable as a structural material in LBE (liquid eutectic Pb 45 Bi 55 ) up to 550 deg. C, if 10 -6 wt% of oxygen is dissolved in the LBE. The martensitic steel develops a thick magnetite and spinel layer while the austenites have thin spinel surface layers at 420 deg. C and thick oxide scales like the martensitic steel at 550 deg. C. The oxide scales protect the steels from dissolution attack by LBE during the whole test period of 7200 h. Oxide scales that spall off are replaced by new protective ones. At 600 deg. C severe attack occurs already after 2000 and 4000 h of exposure. Steels with 8-15 wt% Al alloyed into the surface suffer no corrosion attack at all experimental temperatures and exposure times

  9. A potentiostatic and galvanostatic study of the selective dissolution of Cd/Pb eutectic alloy

    International Nuclear Information System (INIS)

    Sokharev, N.P.; Rabdel, A.A.; Zhadanov, V.V.

    1986-01-01

    The authors consider the selective dissolution (SD) of the electronegative component of a two-phase, eutectic alloy (Cd/Pb) under galvanostatic conditions. Treating this process as the extraction of a solid substance from a porous matrix, the distribution of the concentration of EC ions, c(x, t), can be described by a differential equation (presented). Experimental data are presented in two equations which are applicable for the description of the selective dissolution process of the electronegative component of a eutectic alloy under conditions of concentration polarization

  10. Directional solidification of filamentary shapes of Pb--Cd and Pb--Sn eutectic alloys

    International Nuclear Information System (INIS)

    Dhindaw, B.K.; Verhoeven, J.D.; Spencer, C.R.; Gibson, E.D.

    1978-01-01

    Eutectic alloys of Pb--Cd and Pb--Sn were directionally solidified as thin filamentary strips contained in stainless steel and quartz capillaries. As the solidification rate increased the filament width, w, had to be reduced to maintain complete alignment of the lamellae clear across the filament. It was determined that in order to achieve complete alignment the ratio of filament width to lamellar spacing, w/lambda had to be less than about 30. Experiments were carried out at rates of 2-400 μm/s and at temperature gradients of 130 and 320 0 C/cm

  11. Development of heat resistant Pb-free joints by TLPS process of Ag and Sn-Bi-Ag alloy powders

    Directory of Open Access Journals (Sweden)

    Ohnuma I.

    2012-01-01

    Full Text Available TLPS (Transient Liquid Phase Sintering process is a candidate method of heat-resistant bonding, which makes use of the reaction between low-melting temperature powder of Sn-Bi base alloys and reactive powder of Ag. During heat treatment above the melting temperature of a Sn-Bi base alloy, the molten Sn-Bi reacts rapidly with solid Ag particles, which results in the formation of heat-resistant intermetallic compound (IMC. In this study, the TLPS properties between Sn-17Bi-1Ag (at.% powder with its liquidus temperature of 200°C and pure Ag powder were investigated. During differential scanning calorimetry (DSC measurement, an exothermic reaction and an endothermic reaction occurred, which correspond to the formation of the e-Ag3Sn IMC phase and the melting of the Sn-17Bi-1Ag alloy, respectively. After the overall measurement, the obtained reactant consists of the Ag3Sn-IMC and Bi-rich phases, both of which start melting above 250°C, with a small amount of the residual Sn-Bi eutectic phase. These results suggest that the TLPS process can be applied for Pb-free heatresistant bonding.

  12. The influence of high gravity in PbSn eutectic alloy

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, F.E.; Toledo, R.C.; Poli, A.K.S.; An, C.Y.; Bandeira, I.N., E-mail: filipe.estevao@gmail.com, E-mail: chen@las.inpe.br [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil)

    2014-07-01

    The study of materials processed in centrifuges improves the understanding of the acceleration influence in the convection behavior in materials processing. This work aims to study the influence of high gravity in PbSn eutectic alloy solidification using a small centrifuge designed and built in the Associate Laboratory of Sensors and Materials of the Brazilian Space Research Institute (LAS/INPE). The samples were analyzed by densitometry and scanning electron microscopy (SEM). (author)

  13. Ternary equilibria in bismuth--indium--lead alloys

    International Nuclear Information System (INIS)

    Liao, K.C.; Johnson, D.L.; Nelson, R.C.

    1975-01-01

    The liquidus surface is characterized by three binary equilibria. One binary extends from the Pb--Bi peritectic to the Pb--In peritectic. The other two extend from In--Bi eutectics, merge at 50 at. percent Bi and 30 at. percent Pb, and end at the Bi--Pb eutectic. Based on analysis of ternary liquidus contours and vertical sections, it is suggested that solidification for high lead and very high indium alloys occurs from two-phase equilibria. Solidification from all other alloys occurs from three-phase equilibria. Four-phase solidification does not occur in this system

  14. Study on the morphology of Pb-Sn eutectics

    International Nuclear Information System (INIS)

    Ambrozio Filho, F.; Gentile, E.F.

    1976-01-01

    The influence of factors such as rate of growth of the solid phase, thermal gradient in the liquid and presence of impurities on the solidification of eutectic structures is studied. To emphasize certain aspects of the basic concept, the technique of unidirectional cooling was used in a specially constructed apparatus. Micrographs of the structure obtained with the eutectic Pb-Sn alloy are shown and a purely qualitative analysis of the factors described is given [pt

  15. Evaluation of the effect of Bi, Sb, Sr and cooling condition on eutectic phases in an Al–Si–Cu alloy (ADC12) by in situ thermal analysis

    International Nuclear Information System (INIS)

    Farahany, S.; Ourdjini, A.; Idrsi, M.H.; Shabestari, S.G.

    2013-01-01

    Highlights: • Combined effect of Bi, Sb and Sr additions, and cooling condition was evaluated. • Two different scenarios of recalecense in response to cooling rate were observed. • Fraction solid increased in the order of Sr > Bi > Sb, corresponds to Si morphologies. • Only Bi decreased the nucleation temperature of Al 2 Cu eutectic phase. - Abstract: Al–Si and Al–Cu eutectic phases strongly affect the properties of Al–Si–Cu cast alloys. The characteristic parameters of these two eutectic phases with addition of bismuth, antimony and strontium under different cooling rates (0.6–2 °C/s) were investigated in ADC12 alloy using in situ thermal analysis. Results show that additives affect the Al–Si phase more than the Al–Cu (Al 2 Cu) phase. Addition elements showed two different scenarios in response to cooling rate in terms of recalescence of the Al–Si eutectic phase. Both Bi and Sb caused an increase in recalescence with increased cooling rate but Sr addition reduced the recalescence. Additions of Sb and Sr increased the nucleation temperature of Al 2 Cu, but addition of Bi produced an opposite effect. There seems to be relationship between the solidification temperature range and fraction solid of Al–Si and Al 2 Cu eutectic phases. As the cooling rate increases the fraction solid of Al–Si decreased and that of Al 2 Cu increased

  16. Vaporization of liquid Pb-Li eutectic alloy from 1000K to 1200K - A high temperature mass spectrometric study

    Science.gov (United States)

    Jain, U.; Mukherjee, A.; Dey, G. K.

    2017-09-01

    Liquid lead-lithium eutectic will be used as a coolant in fusion reactor blanket loop. Vapor pressure of the eutectic is an important parameter to accurately predict its in-loop behavior. Past measurements of vapor pressure of the eutectic relied on indirect methods. In this paper, we report for the first time the in-situ vaporization behavior of the liquid alloy between 1042 and 1176 K by Knudsen effusion mass spectrometry (KEMS). It was seen that the vaporization occurred by independent evaporation of lead and lithium. No complex intermetallic vapor was seen in the mass spectra. The partial pressures and enthalpy of vaporization of Pb and Li were evaluated directly from the measured ion intensities formed from the equilibrium vapor over the alloy. The activity of Li over a temperature range of 1042-1176 K was found to be 4.8 × 10-5 to that of pure Li, indicating its very low activity in the alloy.

  17. Evaluation of the effect of Bi, Sb, Sr and cooling condition on eutectic phases in an Al–Si–Cu alloy (ADC12) by in situ thermal analysis

    Energy Technology Data Exchange (ETDEWEB)

    Farahany, S., E-mail: saeedfarahany@gmail.com [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia (UTM), 81310 Johor Bahru (Malaysia); Ourdjini, A.; Idrsi, M.H. [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia (UTM), 81310 Johor Bahru (Malaysia); Shabestari, S.G. [Center of Excellence for High Strength Alloys Technology (CEHSAT), School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), 16846-13114 Tehran (Iran, Islamic Republic of)

    2013-05-10

    Highlights: • Combined effect of Bi, Sb and Sr additions, and cooling condition was evaluated. • Two different scenarios of recalecense in response to cooling rate were observed. • Fraction solid increased in the order of Sr > Bi > Sb, corresponds to Si morphologies. • Only Bi decreased the nucleation temperature of Al{sub 2}Cu eutectic phase. - Abstract: Al–Si and Al–Cu eutectic phases strongly affect the properties of Al–Si–Cu cast alloys. The characteristic parameters of these two eutectic phases with addition of bismuth, antimony and strontium under different cooling rates (0.6–2 °C/s) were investigated in ADC12 alloy using in situ thermal analysis. Results show that additives affect the Al–Si phase more than the Al–Cu (Al{sub 2}Cu) phase. Addition elements showed two different scenarios in response to cooling rate in terms of recalescence of the Al–Si eutectic phase. Both Bi and Sb caused an increase in recalescence with increased cooling rate but Sr addition reduced the recalescence. Additions of Sb and Sr increased the nucleation temperature of Al{sub 2}Cu, but addition of Bi produced an opposite effect. There seems to be relationship between the solidification temperature range and fraction solid of Al–Si and Al{sub 2}Cu eutectic phases. As the cooling rate increases the fraction solid of Al–Si decreased and that of Al{sub 2}Cu increased.

  18. Reply to "On Vaporization of liquid Pb-Li eutectic alloy from 1000 K to 1200 K- A high temperature mass spectrometric study"

    Science.gov (United States)

    Jain, Uttam; Mukherjee, Abhishek

    2018-03-01

    This communication is in response to a letter to editor commenting on the authors' earlier paper "Vaporization of liquid Pb-Li eutectic alloy from 1000 K to 1200 K - A high temperature mass spectrometric study".

  19. Effect of composition on the fabrication and properties of Ag-Cu alloy sheathed (Bi,Pb)2223 tapes

    International Nuclear Information System (INIS)

    Nakamura, Yuichi; Nakashima, Sohei; Inada, Ryoji; Oota, Akio

    2004-01-01

    To achieve high J c values as well as high mechanical strength, the effects of Ag-Cu alloy sheath and initial composition of precursor on the microstructure and J c properties of Ag-Cu alloy sheathed tapes were investigated. The alkaline-earth cuprate particles were found to form preferentially near the interface between superconducting core and sheath. Although the worse (Bi,Pb)2223 purity and microstructure of alloy sheathed tapes, the reduction of J c values of the tapes was small especially in 7-filaments tapes. This might be explained by the well grain alignment of (Bi,Pb)2223 into the middle region of the filament due to the high strength of alloy sheath. The usage of the Cu deficient composition was effective to reduce the total amount of 14:24 particle while the filament thickness should be thin to maintain J c values for Ag-Cu alloy sheathed tapes due to the lack of Cu diffusion from the sheath to convert 2212 into (Bi,Pb) in the middle region of the filament

  20. Calorimetric investigation of (Pb0.45Bi0.55)-U system

    International Nuclear Information System (INIS)

    Agarwal, Renu; Samui, Pradeep; Mukerjee, S.K.; Ramakumar, K.L.

    2016-01-01

    Lead-bismuth eutectic (LBE) is being considered as a coolant of future high temperature reactors. As lead and bismuth are good spallation target material, they are planned to be used in accelerator driven reactor systems (ADS). Under the clad breach conditions these elements may come in direct contact with uranium of metallic fuel. In our labs, we had earlier investigated binary interactions of U-Pb and U-Bi. To assess interaction behaviour of 'U' with the eutectic melt, it was planned to measure enthalpy of mixing of LBE-U and compares it with the binary mixing. SEM-EDS studies of the product formed after mixing of LBE and 'U' were carried out to establish coexisting phases and their compositions. UPb 3 is Pb-rich compound of U-Pb and UBi 2 is Bi-rich compound of U-Bi. So addition of 'U' in (Pb 0.45 Bi 0.55 ) will result in formation of the more stable compound among UPb 3 and UBi 2

  1. Internal friction behavior of liquid Bi-Sn alloys

    International Nuclear Information System (INIS)

    Wu Aiqing; Guo Lijun; Liu Changsong; Jia Erguang; Zhu Zhengang

    2005-01-01

    Pure Bi and Sn and four Bi-Sn alloys distributed on the entire concentration range were selected for internal-friction investigation over a wide temperature range. There exist two peaks in the plots of internal friction versus temperature for liquid Sn, Bi-Sn60 and Bi-Sn90 alloys, one peak being located at about 480 - bar Cand another at about 830 - bar C. Only a single internal-friction peak at about 830 - bar C occurs in liquid Bi-Sn43 (eutectic composition). No internal-friction peak appears in liquid Bi-Sn20 alloy and pure Bi. The height of the internal-friction peaks depends on the content of Sn. The present finding suggests that Sn-rich Bi-Sn alloys may inherit the internal-friction behaviors of pure Sn, whereas Bi-rich Bi-Sn alloy seems to be like pure Bi. The position of the internal-friction peaks is frequency dependent, which resembles the internal-friction feature in structure transition in solids

  2. Internal friction behavior of liquid Bi-Sn alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wu Aiqing [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Guo Lijun [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Liu Changsong [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Jia Erguang [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Zhu Zhengang [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China)]. E-mail: zgzhu@issp.ac.cn

    2005-12-01

    Pure Bi and Sn and four Bi-Sn alloys distributed on the entire concentration range were selected for internal-friction investigation over a wide temperature range. There exist two peaks in the plots of internal friction versus temperature for liquid Sn, Bi-Sn60 and Bi-Sn90 alloys, one peak being located at about 480{sup -}bar Cand another at about 830{sup -}bar C. Only a single internal-friction peak at about 830{sup -}bar C occurs in liquid Bi-Sn43 (eutectic composition). No internal-friction peak appears in liquid Bi-Sn20 alloy and pure Bi. The height of the internal-friction peaks depends on the content of Sn. The present finding suggests that Sn-rich Bi-Sn alloys may inherit the internal-friction behaviors of pure Sn, whereas Bi-rich Bi-Sn alloy seems to be like pure Bi. The position of the internal-friction peaks is frequency dependent, which resembles the internal-friction feature in structure transition in solids.

  3. Martensitic transformation behavior in Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jai-young; Chun, Su-jin; Kim, Nam-suk; Cho, Jeung-won; Kim, Jae-hyun [School of Materials Science and Engineering, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of); Yeom, Jong-taek [Light Metal Division, Korea Institute of Materials Science (KIMS), Changwon 642-831 (Korea, Republic of); Kim, Jae-il [Materials Science and Engineering, University of Dong-A, Hadan-dong, Saha-gu, Busan 604-714 (Korea, Republic of); Nam, Tae-hyun, E-mail: tahynam@gnu.ac.kr [School of Materials Science and Engineering, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of)

    2013-12-15

    Graphical abstract: - Highlights: • Ag, In and Sn were soluble in TiNi matrix, while Sb, Te, Tl, Pb and Bi were not. • The B2-R-B19′transformation occurred in Ti-Ni-(Ag, In, Sn) alloys. • Solid solution hardening was essential for inducing the B2-R transformation. - Abstract: The microstructures and transformation behaviors of Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys were investigated using electron probe micro-analysis (EPMA), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Micro Vickers hardness tests. All specimens consisted of Ti–Ni matrices and second phase particles. Ag, In and Sn were soluble in Ti–Ni matrices with a limited solubility (≤1.0 at%), while Sb, Te, Tl, Pb and Bi were not soluble. Two-stage B2-R-B19′ transformation occurred in Ti–48.8Ni–1.2Ag, Ti–49.0Ni–1.0In and Ti–49.0Ni–1.0Sn alloys, while one-stage B2-B19′ transformation occurred in Ti–49.0Ni–1.0Ag, Ti–49.0Ni–1.0Sb, Ti–49.0Ni–1.0Te, Ti–49.0Ni–1.0Pb and Ti–49.0Ni–1.0Bi alloys. Micro Vickers hardness of the alloys displaying the B2-R-B19′ transformation (Hv 250–368) was much larger than that (alloys displaying the B2-B19′ transformation. Solid solution hardening was an important factor for inducing the B2-R transformation in Ti–Ni–X (X = non-transition elements) alloys.

  4. Martensitic transformation behavior in Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys

    International Nuclear Information System (INIS)

    Jang, Jai-young; Chun, Su-jin; Kim, Nam-suk; Cho, Jeung-won; Kim, Jae-hyun; Yeom, Jong-taek; Kim, Jae-il; Nam, Tae-hyun

    2013-01-01

    Graphical abstract: - Highlights: • Ag, In and Sn were soluble in TiNi matrix, while Sb, Te, Tl, Pb and Bi were not. • The B2-R-B19′transformation occurred in Ti-Ni-(Ag, In, Sn) alloys. • Solid solution hardening was essential for inducing the B2-R transformation. - Abstract: The microstructures and transformation behaviors of Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys were investigated using electron probe micro-analysis (EPMA), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Micro Vickers hardness tests. All specimens consisted of Ti–Ni matrices and second phase particles. Ag, In and Sn were soluble in Ti–Ni matrices with a limited solubility (≤1.0 at%), while Sb, Te, Tl, Pb and Bi were not soluble. Two-stage B2-R-B19′ transformation occurred in Ti–48.8Ni–1.2Ag, Ti–49.0Ni–1.0In and Ti–49.0Ni–1.0Sn alloys, while one-stage B2-B19′ transformation occurred in Ti–49.0Ni–1.0Ag, Ti–49.0Ni–1.0Sb, Ti–49.0Ni–1.0Te, Ti–49.0Ni–1.0Pb and Ti–49.0Ni–1.0Bi alloys. Micro Vickers hardness of the alloys displaying the B2-R-B19′ transformation (Hv 250–368) was much larger than that (< Hv 200) of the alloys displaying the B2-B19′ transformation. Solid solution hardening was an important factor for inducing the B2-R transformation in Ti–Ni–X (X = non-transition elements) alloys

  5. General characteristics of eutectic alloy solidification mechanisms

    International Nuclear Information System (INIS)

    Lemaignan, Clement.

    1977-01-01

    The eutectic alloy sodification was studied in binary systems: solidification of non facetted - non facetted eutectic alloy (theoretical aspects, variation of the lamellar spacing, crystallographic relation between the various phases); solidification of facetted - non facetted eutectic alloy; coupled growth out of eutectic alloy; eutectic nucleation [fr

  6. Free energy change of off-eutectic binary alloys on solidification

    Science.gov (United States)

    Ohsaka, K.; Trinh, E. H.; Lin, J.-C.; Perepezko, J. H.

    1991-01-01

    A formula for the free energy difference between the undercooled liquid phase and the stable solid phase is derived for off-eutectic binary alloys in which the equilibrium solid/liquid transition takes place over a certain temperature range. The free energy change is then evaluated numerically for a Bi-25 at. pct Cd alloy modeled as a sub-subregular solution.

  7. Reference Data for the Density, Viscosity, and Surface Tension of Liquid Al-Zn, Ag-Sn, Bi-Sn, Cu-Sn, and Sn-Zn Eutectic Alloys

    Science.gov (United States)

    Dobosz, Alexandra; Gancarz, Tomasz

    2018-03-01

    The data for the physicochemical properties viscosity, density, and surface tension obtained by different experimental techniques have been analyzed for liquid Al-Zn, Ag-Sn, Bi-Sn, Cu-Sn, and Sn-Zn eutectic alloys. All experimental data sets have been categorized and described by the year of publication, the technique used to obtain the data, the purity of the samples and their compositions, the quoted uncertainty, the number of data in the data set, the form of data, and the temperature range. The proposed standard deviations of liquid eutectic Al-Zn, Ag-Sn, Bi-Sn, Cu-Sn, and Sn-Zn alloys are 0.8%, 0.1%, 0.5%, 0.2%, and 0.1% for the density, 8.7%, 4.1%, 3.6%, 5.1%, and 4.0% for viscosity, and 1.0%, 0.5%, 0.3%, N/A, and 0.4% for surface tension, respectively, at a confidence level of 95%.

  8. Reliability of Pb free solder alloys. Physical and mechanical properties; Pb free handa no shinraisei. Butsuri kikaiteki shinraisei

    Energy Technology Data Exchange (ETDEWEB)

    Sanji, M; Yoshino, M; Ishikawa, J; Takenaka, O [Denso Corp., Aichi (Japan)

    1997-10-01

    Properties of 19 different Pb free solders have been evaluated in comparison with Sn-37Pb eutectic solder. Pb free solders without Bi were on the same level as Sn-37Pb in tensile strength and elongation, and those with Bi had higher strength and lower elongation than Sn-37Pb. As the Bi content increased, strength was higher, and elongation was lower. In torsion fatigue tests, fatigue life of Pb free solders without Bi was longer than Sn-37Pb. The relationships of Coffin-Manson rule and Basquin rule with fatigue life was applicable to Pb free solder. Fatigue life of those is inferred from their tensile strength. 7 refs., 13 figs., 1 tab.

  9. Diffuse scattering from the liquid-vapor interfaces of dilute Bi:Ga, Tl:Ga, and Pb:Ga alloys

    International Nuclear Information System (INIS)

    Li Dongxu; Jiang Xu; Rice, Stuart A.; Lin Binhua; Meron, Mati

    2005-01-01

    As part of a study of the in-plane wave-vector (q xy ) dependence of the effective Hamiltonian for the liquid-vapor interface, H(q), the wave-vector dependences of diffuse x-ray scattering from the liquid-vapor interfaces of dilute alloys of Bi in Ga, Tl in Ga, and Pb in Ga have been measured. In these dilute alloys the solute component segregates as a monolayer that forms the outermost stratum of the liquid-vapor interfaces, and the density distribution along the normal to the interface is stratified. Over the temperature ranges that the alloy interfaces were studied, the Tl and Pb monolayers exhibit both crystalline and liquid phases while the Bi monolayer is always liquid. The diffuse scattering from the liquid-vapor interfaces of these alloys displays interesting differences with that from the liquid-vapor interface of pure Ga. The presence of a segregated monolayer of solute in the liquid-vapor interface of the alloy appears to slightly suppress the fluctuations in an intermediate wave-vector range in a fashion that preserves the validity of the macroscopic capillary wave model to smaller wavelengths than in pure liquid Ga, and there is an increase in diffuse scattering when the Tl and Pb monolayers melt. The surface intrinsic roughness from fitting the wave-vector dependence of surface tension is 5.0 pm for the Tl:Ga alloy and 1.4 pm for the Bi:Ga alloy. Also, a mode of excitation that contributes to diffuse scattering from the liquid-vapor interface of Pb in Ga, but does not contribute to diffuse scattering from the liquid-vapor interface of Ga, has been identified. It is proposed that this mode corresponds to the separation of the Pb and Ga layers in the regime 1 nm -1 ≤q xy ≤10 nm -1

  10. Flux flow and proximity effects in aligned Pb--Cd eutectic lamellar structures

    International Nuclear Information System (INIS)

    Spencer, C.R.

    1977-09-01

    A high speed directional solidification technique was used to fabricate lamellar Pb-Cd and (Pb-Mg)--(Cd-Mg) superconductor-normal metal composites in which all the lamellae are oriented perpendicular to the broad surface of the sample. These lamellar composites are found to behave like a large number (approximately 1000) of superconducting-normal-superconducting junctions. For the Pb-Cd eutectic system, the critical current densities and critical fields have shown no dependence upon the lamellar periods between 1.0 and 3.1 microns. The critical current density of the aligned lamellar Pb-Cd structures was enhanced approximately 50% when compared to quenched eutectic alloy and to pure Pb. The superconducting transition temperature, T/sub c/, varies inversely with the square of the thickness of the superconducting material as expected from Ginzburg-Landau theory. Upon annealing, the Pb lamellae change from type II to type I superconductivity

  11. Flux flow and proximity effects in aligned Pb--Cd eutectic lamellar structures

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, C. R.

    1977-09-01

    A high speed directional solidification technique was used to fabricate lamellar Pb-Cd and (Pb-Mg)--(Cd-Mg) superconductor-normal metal composites in which all the lamellae are oriented perpendicular to the broad surface of the sample. These lamellar composites are found to behave like a large number (approximately 1000) of superconducting-normal-superconducting junctions. For the Pb-Cd eutectic system, the critical current densities and critical fields have shown no dependence upon the lamellar periods between 1.0 and 3.1 microns. The critical current density of the aligned lamellar Pb-Cd structures was enhanced approximately 50% when compared to quenched eutectic alloy and to pure Pb. The superconducting transition temperature, T/sub c/, varies inversely with the square of the thickness of the superconducting material as expected from Ginzburg-Landau theory. Upon annealing, the Pb lamellae change from type II to type I superconductivity.

  12. Developments of high strength Bi-containing Sn0.7Cu lead-free solder alloys prepared by directional solidification

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xiaowu, E-mail: xwhmaterials@aliyun.com [School of Mechanical Electrical Engineering, Nanchang University, Nanchang 330031 (China); Li, Yulong [School of Mechanical Electrical Engineering, Nanchang University, Nanchang 330031 (China); Liu, Yi [School of Materials Science and Engineering, Nanchang University, Nanchang 330031 (China); Min, Zhixian [China Electronics Technology Group Corporation No. 38 Research Institute, Hefei 230088 (China)

    2015-03-15

    Highlights: • The Sn0.7Cu–xBi solder alloys were directionally solidified. • Both spacing and diameter of fibers decreased with increasing solidification rate. • The UTS and YS first increased with increased solidification rate, then decreased. • The UTS and YS of Sn0.7Cu–xBi first increased with increased Bi content. - Abstract: Bi-containing Sn0.7Cu (SC) eutectic solder alloys were prepared and subjected to directional solidification, through which new types of fiber reinforced eutectic composites were generated. The influences of Bi addition on the microstructures and tensile properties of directionally solidified (DS) Bi-containing eutectic SC lead-free solder alloys have been investigated by using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and a tensile testing machine. The experimental results showed that addition of Bi could effectively reduce both the melting temperature and undercooling of SC solder alloy. The microstructures of DS SC–xBi solder alloys were composed of Sn-rich phase (β) and Cu{sub 6}Sn{sub 5} fiber. No other intermetallic compounds (IMCs) with Bi content were observed in the solder matrix for SC solder alloys with various Bi contents. Both fiber spacing and diameter all decreased gradually with increasing growth rate and/or Bi content. Besides, the regularity of Cu{sub 6}Sn{sub 5} fibers alignment also decreased with increasing growth rate, too. The tensile strengths of the SC–xBi eutectic solder alloys varied parabolically with growth rate (R). When R was 60 μm/s, maximum tensile strengths of 43.8, 55.2 and 56.37 MPa were reached for SC, SC0.7Bi and SC1.3Bi solder alloys. A comparison of tensile strength of SC, SC0.7Bi and SC1.3Bi with the same R indicated that the tensile strength increased with increasing Bi content, which was attributed to the presence of Bi and its role in refining microstructure and solid solution strengthening.

  13. Preparation, microstructure and thermal properties of Mg−Bi alloys as phase change materials for thermal energy storage

    International Nuclear Information System (INIS)

    Fang, Dong; Sun, Zheng; Li, Yuanyuan; Cheng, Xiaomin

    2016-01-01

    Highlights: • The microstructure and thermal properties of Mg−Bi alloys are determined. • The relationship between melting enthalpies and phase composition are studied. • The activation energy of Mg−54%Bi alloy is calculated by multiple DSC technology. • Mg−54%Bi alloy is proposed as a phase change material at high (>420 °C) temperature. - Abstract: Comparing with Al-based phase change material, Mg-based phase change material is getting more and more attention due to its high corrosion resistance with encapsulation materials based on iron. This study focuses on the characterization of Mg−36%Bi, Mg−54%Bi and Mg−60%Bi (wt. %) alloys as phase change materials for thermal energy storage at high temperature. The phase compositions, microstructure and phase change temperatures were investigated by X-ray diffusion (XRD), electron probe micro-analysis (EPMA) and differential scanning calorimeter (DSC) analysis, respectively. The results indicates that the microstructure of Mg−36%Bi and Mg−54%Bi alloys are mainly composed of α-Mg matrix and α-Mg + Mg_3Bi_2 eutectic phases, Mg−60%Bi alloy are mainly composed of the Mg_3Bi_2 phase and α-MgMg_3Bi_2 eutectic phases. The melting enthalpies of Mg−36%Bi, Mg−54%Bi and Mg−60%Bi alloys are 138.2, 180.5 and 48.7 J/g, with the phase change temperatures of 547.6, 546.3 and 548.1 °C, respectively. The Mg−54%Bi alloy has the highest melting enthalpy in three alloys. The main reason may be that it has more proportion of α-Mg + Mg_3Bi_2 eutectic phases. The thermal expansion of three alloys increases with increasing temperature. The values of the thermal conductivity decrease with increasing Bi content. Besides, the activation energy of Mg−54%Bi was calculated by multiple DSC technology.

  14. Nano-Channels Early Formation Investigation on Stainless Steel 316Ti after Immersion in Molten Pb-Bi

    Directory of Open Access Journals (Sweden)

    Abu Khalid Rivai

    2017-04-01

    Full Text Available Pb-Bi (lead-bismuth eutectic-LBE is a coolant of one of main candidates for the future nuclear reactor in the world (Generation IV reactors i.e. LFR (Lead alloy-cooled Fast Reactor, and also a spallation target material for ADS (Accelerator Driven Transmutation System. However, the development of fuel cladding and structural materials in LBE environment, especially at high temperature, is a critical issue for the deployment of LFR and ADS. This is because of the corrosive characteristic of LBE to metals as constituent materials of fuel cladding and structural of the reactors. In this study, corrosion test of a high-chromium austenitic steel i.e. SS316Ti in liquid Pb-Bi at 550ºC has been carried out for about 300 hours. The characterization using SEM-EDS (Scanning Electron Microscope-Energy Dispersive X-ray Spectroscope showed that an iron oxide as the outer layer and a chromium oxide as the inner layer on the surface of the specimen were formed which protected the steel specimen from corrosion and dissolution attack of Pb-Bi. However, small amount of Pb-Bi could penetrate into the iron oxide layer through ultra-thin channels. Atomic Force Microscopy (AFM was employed to investigate the phenomena of the channels formation. The results of the nano-scale investigation showed clearly the formation of the channels.

  15. Preparation and characterization of the Li(17)Pb(83) eutectic alloy and the LiPb intermetallic compound

    International Nuclear Information System (INIS)

    Jauch, U.; Karcher, V.; Schulz, B.

    1986-01-01

    Li(17)Pb(83) and LiPb were prepared from the pure elements in amounts of several hundred grams. The resolidified samples were characterized by melting points (eutectic temperature), chemical analysis and metallography. Using differential thermal analysis the heats of fusion were determined and the behaviour of the intermetallic phase LiPb in vacuum and high purified He was studied. The results from these investigations were applied to characterize Li(17)Pb(83) prepared in high amounts for technical application as a potential liquid breeder material. (orig.)

  16. Compatibility of different stainless steels in molten Pb-Bi eutectic at high temperatures

    International Nuclear Information System (INIS)

    Chandra, K.; Kain, Vivekanand; Laik, A.; Sharma, B.P.; Bhattacharya, S.; Debnath, A.K.

    2005-10-01

    Advanced nuclear reactors and the accelerator driven subcritical (ADS) system require the structural materials to be in contact with the molten metals/lead-bismuth eutectic at 400 degC and higher temperatures. One of the primary concerns in using the molten lead-bismuth eutectic (LBE) as a coolant in the primary circuit of these systems is the degradation of structural materials in contact with LBE. An experimental setup has been fabricated to expose the materials in the molten LBE at high temperatures in stagnant condition under inert atmosphere. Samples from five different stainless steels (types 304L, 316L, 403, duplex SS SAF 2205 and super austenitic SS 2RK65) were exposed in this setup at 450 degC for 200h and at 500 degC for 600 and 2100 h under argon atmosphere. A different setup was prepared in which type 316L SS tube in the as-welded condition was exposed in molten LBE at 500 degC for 1200 h in rotating condition. All the samples showed formation of oxide on their surfaces. The thickness and compositional profiles of these oxides analyzed by EPMA confirmed formation of a double layer oxide on type 316L SS. The oxide thickness was highest on SS 403, while it was lowest on 304L and 316L SS. SEM results showed dissolution of materials at the surface in Sandvik 2RK65 and preferential dissolution of austenite phase in duplex SS. None of the stainless steels, except the duplex and the super austenitic stainless steels, showed any localized or selective corrosion. The composition of LBE before and after the exposure tests was analyzed by XRF technique. The result showed presence of Fe, Cr and Ni in the used LBE but these elements were not present in the virgin Pb-Ei alloy. This showed that the corrosion of stainless steels in LBE at temperatures upto 500 degC is due to oxidation and dissolution of alloying elements through the oxide on stainless steels. (author)

  17. Measurement of solid-liquid interfacial energy in the In-Bi eutectic alloy at low melting temperature

    International Nuclear Information System (INIS)

    Marasli, N; Akbulut, S; Ocak, Y; Keslioglu, K; Boeyuek, U; Kaya, H; Cadirli, E

    2007-01-01

    The Gibbs-Thomson coefficient and solid-liquid interfacial energy of the solid In solution in equilibrium with In Bi eutectic liquid have been determined to be (1.46 ± 0.07) x 10 -7 K m and (40.4 ± 4.0) x 10 -3 J m -2 by observing the equilibrated grain boundary groove shapes. The grain boundary energy of the solid In solution phase has been calculated to be (79.0 ± 8.7) x 10 -3 J m -2 by considering force balance at the grain boundary grooves. The thermal conductivities of the In-12.4 at.% Bi eutectic liquid phase and the solid In solution phase and their ratio at the eutectic melting temperature (72 deg. C) have also been measured with radial heat flow apparatus and Bridgman-type growth apparatus

  18. Microstructural evolution and tensile properties of Sn-Ag-Cu mixed with Sn-Pb solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wang Fengjiang [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States); O' Keefe, Matthew [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States)], E-mail: mjokeefe@mst.edu; Brinkmeyer, Brandon [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States)

    2009-05-27

    The effect of incorporating eutectic Sn-Pb solder with Sn-3.0Ag-0.5Cu (SAC) Pb-free solder on the microstructure and tensile properties of the mixed alloys was investigated. Alloys containing 100, 75, 50, 25, 20, 15, 10, 5 and 0 wt% SAC, with the balance being Sn-37Pb eutectic solder alloy, were prepared and characterized. Optical and scanning electron microscopy were used to analyze the microstructures while 'mini-tensile' test specimens were fabricated and tested to determine mechanical properties at the mm length scale, more closely matching that of the solder joints. Microstructural analysis indicated that a Pb-rich phase formed and was uniformly distributed at the boundary between the Sn-rich grains or between the Sn-rich and the intermetallic compounds in the solder. Tensile results showed that mixing of the alloys resulted in an increase in both the yield and the ultimate tensile strength compared to the original solders, with the 50% SAC-50% Sn-Pb mixture having the highest measured strength. Initial investigations indicate the formation and distribution of a Pb-rich phase in the mixed solder alloys as the source of the strengthening mechanism.

  19. Modelling Eutectic Growth in Unmodified and Modified Near-Eutectic Al-Si Alloy

    DEFF Research Database (Denmark)

    Tiedje, Niels Skat; Hattel, Jesper Henri; Taylor, John A.

    2013-01-01

    growth parameters from the literature that depend on the type of modification (unmodified, Na-modified or Sr-modified) are used to describe differences in growth of the alloys. Modelling results are compared with solidification experiments where an Al-12.5wt%Si alloy was cast in unmodified, Na modified......A numerical model that describes solidification of primary aluminium grains and nucleation and growth of eutectic cells is used to analyse the solidification of an Al-12.5wt% Si alloy. Nucleation of eutectic cells is modelled using an Oldfield-type nucleation model where the number of nuclei...... and Sr modified forms. The model confirms experimental observations of how modification and alloy composition influence nucleation, growth and finally the size of eutectic cells in the alloys. Modelling results are used to explain how cooling conditions in the casting act together with the nuclei density...

  20. Solidification of eutectic system alloys in space (M-19)

    Science.gov (United States)

    Ohno, Atsumi

    1993-01-01

    It is well known that in the liquid state eutectic alloys are theoretically homogeneous under 1 g conditions. However, the homogeneous solidified structure of this alloy is not obtained because thermal convection and non-equilibrium solidification occur. The present investigators have clarified the solidification mechanisms of the eutectic system alloys under 1 g conditions by using the in situ observation method; in particular, the primary crystals of the eutectic system alloys never nucleated in the liquid, but instead did so on the mold wall, and the crystals separated from the mold wall by fluid motion caused by thermal convection. They also found that the equiaxed eutectic grains (eutectic cells) are formed on the primary crystals. In this case, the leading phase of the eutectic must agree with the phase of the primary crystals. In space, no thermal convection occurs so that primary crystals should not move from the mold wall and should not appear inside the solidified structure. Therefore no equiaxed eutectic grains will be formed under microgravity conditions. Past space experiments concerning eutectic alloys were classified into two types of experiments: one with respect to the solidification mechanisms of the eutectic alloys and the other to the unidirectional solidification of this alloy. The former type of experiment has the problem that the solidified structures between microgravity and 1 g conditions show little difference. This is why the flight samples were prepared by the ordinary cast techniques on Earth. Therefore it is impossible to ascertain whether or not the nucleation and growth of primary crystals in the melt occur and if primary crystals influence the formation of the equiaxed eutectic grains. In this experiment, hypo- and hyper-eutectic aluminum copper alloys which are near eutectic point are used. The chemical compositions of the samples are Al-32.4mass%Cu (Hypo-eutectic) and Al-33.5mass%Cu (hyper-eutectic). Long rods for the samples are

  1. Corrosion behavior of materials in a liquid Pb-Bi spallation target

    International Nuclear Information System (INIS)

    Barbier, F.; Balbaud, F.; Deloffre, P.; Terlain, A.

    2001-01-01

    Corrosion results of austenitic and martensitic steels exposed to Pb-Bi liquid alloy (material candidate for the spallation target of ADS) are presented. They show the large influence of parameters such as the oxygen content in Pb-Bi and the Pb-Bi velocity on the corrosion. At low O 2 content (7 10 -8 wt%) in Pb-Bi the steels can suffer from significant dissolution while at high O 2 (1-2 10 -6 wt%) content they can be covered by an oxide layer which protects them from the dissolution. Moreover it is shown that, in aniso-thermal systems, the deposit chemical composition formed in the cold parts can depend on the temperature. (authors)

  2. Technology for cleaning of Pb-Bi adhering to steel (1). Basic tests

    International Nuclear Information System (INIS)

    Saito, Shigeru; Sasa, Toshinobu; Umeno, Makoto; Kurata, Yuji; Kikuchi, Kenji; Futakawa, Masatoshi

    2004-12-01

    The accelerator driven system (ADS) is proposed to transmute minor actinides (MA) in high-level waste from spent fuels of nuclear power reactors. Liquid Pb-Bi alloy is a candidate material for spallation target and coolant of ADS. Pb-Bi cleaning technology is required to reduce radiation exposure during maintenance service and to decontaminate replaced components. In this study, three cleaning methods were tested; silicon oil cleaning at 170degC, mixture of acetic acid and nitric acid cleaning. Specimens were prepared by immersion in melted Pb-Bi. After silicon oil tests, most of Pb-Bi remained on the surface of the specimens. It was found that blushing was needed to remove Pb-Bi effectively. On the other hands, Pb-Bi was easily dissolved and almost removed in the mixed acid and nitric acid. Silicon oil cleaning did not affect on base metals. The surface of base metals was slightly blacked after mixed acid cleaning. F82H base metals were corroded by nitric acid. (author)

  3. Pseudobinary eutectics in Cu–Ag–Ge alloy droplets under containerless condition

    International Nuclear Information System (INIS)

    Ruan, Y.; Wang, X.J.; Lu, X.Y.

    2013-01-01

    Highlights: ► Two pseudobinary eutectics form in Cu–Ag–Ge alloy. ► It is influenced by thermodynamic and kinetic factors of the alloy in the drop tube. ► As droplet size reduces, anomalous → lamellar → anomalous transition happens in (Ag + ζ). ► (Ag + ε 2 ) is a product of both peri-eutectic and pseudobinary eutectic transitions. -- Abstract: Pseudobinary eutectic generated by pseudobinary eutectic transition or peri-eutectic transition is a crucial structure in ternary alloy systems. Its formation mechanism strongly influences mechanical properties of these metallic materials. However, it was customarily neglected. In this paper, two pseudobinary eutectics, i.e. (Ag + ζ) and (Ag + ε 2 ), were investigated during the rapid solidification of Cu–Ag–Ge ternary alloy in a 3 m-drop tube. The sharp temperature variations and dramatic kinetic activities of the falling alloy droplets before solidification cause special microstructural characteristics. (Ag) dendrite is the heterogeneous nucleus for anomalous (Ag + ζ) pseudobinary eutectic in large droplets. Lamellar (Ag + ζ) pseudobinary eutectic grain forms independently on condition that primary (Ag) dendrite cannot form and its eutectic morphology becomes anomalous with the decrease of droplet size. Nanoscaled (Ag + ε 2 ) pseudobinary eutectic generating at the last stage of solidification is the product of both peri-eutectic and pseudobinary eutectic transitions. It distributes in the gaps of (Ag + ζ) pseudobinary eutectic grains and its morphology remains lamellar regardless of droplet size

  4. Liquid Li-Pb-Bi, a new tritium breeder

    International Nuclear Information System (INIS)

    Rogers, A.G.; Benedict, B.L.; Clemmer, R.G.

    1981-01-01

    In light of their potential utility as tritium breeder-blanket materials, a study was conducted to identify and characterize low-melting phases in the lithium-lead-bismuth system. It is found that a low-melting ternary phase field did in fact exist, e.g., compositions with less than or equal to 20 atom percent lithium and Pb/Bi = 0.773 melted at or below 140 0 C. In addition, the qualitative reactivity of Li-Bi-Pb alloys with water was tested, and although minimal evidence of exothermic chemical reaction was observed, a physical vapor explosion did occur in one of the tests

  5. Comparison of the corrosion behavior of austenitic and ferritic/martensitic steels exposed to static liquid Pb Bi at 450 and 550 °C

    Science.gov (United States)

    Kurata, Y.; Futakawa, M.; Saito, S.

    2005-08-01

    Static corrosion tests of various steels were conducted in oxygen-saturated liquid Pb-Bi eutectic at 450 °C and 550 °C for 3000 h to study the effects of temperature and alloying elements on corrosion behavior in liquid Pb-Bi. Corrosion depth decreases at 450 °C with increasing Cr content in steels regardless of ferritic/martensitic steels or austenitic steels. Appreciable dissolution of Ni and Cr does not occur in the three austenitic steels at 450 °C. Corrosion depth of ferritic/martensitic steels also decreases at 550 °C with increasing Cr content in steels whereas corrosion depth of austenitic steels, JPCA and 316SS becomes larger due to ferritization caused by dissolution of Ni at 550 °C than that of ferritic/martensitic steels. An austenitic stainless steel containing about 5%Si exhibits fine corrosion resistance at 550 °C because the protective Si oxide film is formed and prevents dissolution of Ni and Cr.

  6. Comparison of the corrosion behavior of austenitic and ferritic/martensitic steels exposed to static liquid Pb-Bi at 450 and 550 deg. C

    International Nuclear Information System (INIS)

    Kurata, Y.; Futakawa, M.; Saito, S.

    2005-01-01

    Static corrosion tests of various steels were conducted in oxygen-saturated liquid Pb-Bi eutectic at 450 deg. C and 550 deg. C for 3000 h to study the effects of temperature and alloying elements on corrosion behavior in liquid Pb-Bi. Corrosion depth decreases at 450 deg. C with increasing Cr content in steels regardless of ferritic/martensitic steels or austenitic steels. Appreciable dissolution of Ni and Cr does not occur in the three austenitic steels at 450 deg. C. Corrosion depth of ferritic/martensitic steels also decreases at 550 deg. C with increasing Cr content in steels whereas corrosion depth of austenitic steels, JPCA and 316SS becomes larger due to ferritization caused by dissolution of Ni at 550 deg. C than that of ferritic/martensitic steels. An austenitic stainless steel containing about 5%Si exhibits fine corrosion resistance at 550 deg. C because the protective Si oxide film is formed and prevents dissolution of Ni and Cr

  7. The novel eutectic microstructures of Si-Mn-P ternary alloy

    International Nuclear Information System (INIS)

    Wu Yaping; Liu Xiangfa

    2010-01-01

    The microstructures of Si-Mn-P alloy manufactured by the technique of combining phosphorus transportation and alloy melting were investigated using electron probe micro-analyzer (EPMA). The phase compositions were determined by energy spectrum and the varieties of eutectic morphologies were discussed. It is found that there is no ternary compound but Si, MnP and MnSi 1.75-x could appear when the Si-Mn-P alloy's composition is proper. Microstructure is greatly refined by rapid solidification technique and the amount of eutectic phases change with faster cooling rates. Moreover, primary Si or MnP are surrounded firstly by the binary eutectic (Si + MnP) and then the ternary eutectic (Si + MnSi 1.75-x + MnP) which also exhibit binary structures due to divorced eutectic determined by the particularity of some Si-Mn-P alloys.

  8. Superconducting properties of Pb82Bi18 films controlled by ferromagnetic nanowire arrays

    International Nuclear Information System (INIS)

    Ye Zuxin; Lyuksyutov, Igor F; Wu Wenhao; Naugle, Donald G

    2011-01-01

    The superconducting properties of Pb 82 Bi 18 alloy films deposited on ferromagnetic nanowire arrays have been investigated. Ferromagnetic Co or Ni nanowires are first electroplated into the columnar pores of anodic aluminum oxide (AAO) membranes. Superconducting Pb 82 Bi 18 films are then quench condensed onto the polished surface of the AAO membranes filled with magnetic nanowires. A strong dependence of the Pb 82 Bi 18 superconducting properties on the ratio of the superconducting film thickness to the magnetic nanowire diameter and material variety was observed.

  9. Superconducting properties of Pb82Bi18 films controlled by ferromagnetic nanowire arrays

    Science.gov (United States)

    Ye, Zuxin; Lyuksyutov, Igor F.; Wu, Wenhao; Naugle, Donald G.

    2011-02-01

    The superconducting properties of Pb82Bi18 alloy films deposited on ferromagnetic nanowire arrays have been investigated. Ferromagnetic Co or Ni nanowires are first electroplated into the columnar pores of anodic aluminum oxide (AAO) membranes. Superconducting Pb82Bi18 films are then quench condensed onto the polished surface of the AAO membranes filled with magnetic nanowires. A strong dependence of the Pb82Bi18 superconducting properties on the ratio of the superconducting film thickness to the magnetic nanowire diameter and material variety was observed.

  10. Structure of eutectic alloys of Au with Si and Ge

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, S. [Faculty of Sciences, Kyushu University, 4-2-1, Ropponmatsu, Fukuoka 810-8560 (Japan)], E-mail: takeda@rc.kyushu-u.ac.jp; Fujii, H. [Graduate School of Sciences, Kyushu University, 4-2-1, Ropponmatsu, Fukuoka 810-8560 (Japan); Kawakita, Y. [Faculty of Sciences, Kyushu University, 4-2-1, Ropponmatsu, Fukuoka 810-8560 (Japan); Tahara, S.; Nakashima, S. [Graduate School of Sciences, Kyushu University, 4-2-1, Ropponmatsu, Fukuoka 810-8560 (Japan); Kohara, S.; Itou, M. [Japan Synchrotron Radiation Research Institute, 1-1-1 Koto Sayo-cho, Sayo Hyogo 679-5198 (Japan)

    2008-03-06

    Au-Si and Au-Ge alloy systems have a deep eutectic point in the Au-rich concentration region where the melting point falls down to 633 K. In order to investigate the liquid structure in relation to the glass-forming tendency of these alloys, high-energy X-ray diffraction measurements have been carried out at the eutectic composition and at compositions with excess amounts of Au or IVb element. The nearest neighbor correlations in the eutectic liquids are intense and sharp in the pair distribution function and exhibit a rather small temperature dependence in comparison with those alloys of other than the eutectic composition. Structural models for these liquid alloys are proposed with the aid of reverse Monte Carlo simulation. The reproduced atomic arrangements around the eutectic region exhibit a substitutional-type structure where the dense random packing of Au atoms is preserved and Si or Ge atoms occupy the Au-sites at random.

  11. Properties and Microstructures of Sn-Bi-X Lead-Free Solders

    Directory of Open Access Journals (Sweden)

    Fan Yang

    2016-01-01

    Full Text Available The Sn-Bi base lead-free solders are proposed as one of the most popular alloys due to the low melting temperature (eutectic point: 139°C and low cost. However, they are not widely used because of the lower wettability, fatigue resistance, and elongation compared to traditional Sn-Pb solders. So the alloying is considered as an effective way to improve the properties of Sn-Bi solders with the addition of elements (Al, Cu, Zn, Ga, Ag, In, Sb, and rare earth and nanoparticles. In this paper, the development of Sn-Bi lead-free solders bearing elements and nanoparticles was reviewed. The variation of wettability, melting characteristic, electromigration, mechanical properties, microstructures, intermetallic compounds reaction, and creep behaviors was analyzed systematically, which can provide a reference for investigation of Sn-Bi base solders.

  12. Behavior of radioisotope in liquid neutron irradiated Pb-17Li eutectic

    International Nuclear Information System (INIS)

    Tebus, V.N.; Aksenov, B.S.; Klabukov, U.G.

    1994-01-01

    Investigation of radioisotope 210 Po evaporation from liquid neutron irradiated Pb- 17 Li eutectic has been performed by Knudsen method. Equilibrium 210 Po vapor pressures at temperatures 250-700 degrees C were found about 3-4 orders of magnitude less than that for pure Po and were closed to equilibrium vapor pressures of Po-Pb compound. It was proposed Po forms stable Po-Pb compounds in eutectic at temperatures up to 750-800 degrees C. But disintegrates during long storage owing to self irradiation. It was determined Po aerosol transfer with radio gases takes place at the melting period. Contamination is happened also under irradiated eutectic storage at room temperature owing to aggregate recoil characteristic of Po

  13. Initial stages of solidification of eutectic alloys

    International Nuclear Information System (INIS)

    Lemaignan, Clement

    1980-01-01

    The study of the various initial stages of eutectic solidification - i.e. primary nucleation, eutectic structure formation and stable growth conditions - was undertaken with various techniques including low angle neutron diffusion, in-situ electron microscopy on solidifying alloys and classical metallography. The results obtained allow to discuss the effect of metastable states during primary nucleation, of surface dendrite during eutectic nucleation and also of the crystallographic anisotropy during growth. (author) [fr

  14. A new approach to assess the effects of Sr and Bi interaction in ADC12 Al–Si die casting alloy

    International Nuclear Information System (INIS)

    Farahany, Saeed; Ourdjini, Ali; Abu Bakar, Tuty Asma; Idris, Mohd Hasbullah

    2014-01-01

    Highlights: • Interactive effect between Bi and Sr has been invesitigated comprehensively. • Sequence of addition did not affect thermal and microscopical characteristics. • A new map has been established to assess the final microstructure of castings. - Abstract: In the present paper, the possible interaction between bismuth and strontium in ADC12 die casting alloy was investigated comprehensively by using in situ thermal analysis technique. The characteristic temperatures including nucleation, minimum and growth temperatures of eutectic Al–Si were also analyzed. The results show that with Bi present in the Al–Si alloy melt the efficiency of Sr in modifying the eutectic Si is reduced. A threshold Sr/Bi ratio of at least 0.5 is required for a fully modified Si structure to form. A new map based on the characteristic temperatures, Sr/Bi ratio and microstructure, was established to assess the microstructure of fully solidified Al–Si castings

  15. A new approach to assess the effects of Sr and Bi interaction in ADC12 Al–Si die casting alloy

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-10

    Highlights: • Interactive effect between Bi and Sr has been invesitigated comprehensively. • Sequence of addition did not affect thermal and microscopical characteristics. • A new map has been established to assess the final microstructure of castings. - Abstract: In the present paper, the possible interaction between bismuth and strontium in ADC12 die casting alloy was investigated comprehensively by using in situ thermal analysis technique. The characteristic temperatures including nucleation, minimum and growth temperatures of eutectic Al–Si were also analyzed. The results show that with Bi present in the Al–Si alloy melt the efficiency of Sr in modifying the eutectic Si is reduced. A threshold Sr/Bi ratio of at least 0.5 is required for a fully modified Si structure to form. A new map based on the characteristic temperatures, Sr/Bi ratio and microstructure, was established to assess the microstructure of fully solidified Al–Si castings.

  16. Spatial profile of thermoelectric effects during Peltier pulsing in Bi and Bi/MnBi eutectic

    Science.gov (United States)

    Silberstein, R. P.; Larson, D. J., Jr.

    1987-01-01

    The spatial profile of the thermal transients that occur during and following the current pulsing associated with Peltier Interface Demarcation during directional solidification is studied. Results for pure Bi are presented in detail and compared with corresponding results for the Bi/MnBi eutectic. Significant thermal transients occur throughout the sample that can be accounted for by the Peltier effect, the Thomson effect, and Joule heating. These effects are separated and their behavior is studied as a function of time, current density, and position with respect to the solid/liquid interface.

  17. Development of Bi-base high-temperature Pb-free solders with second-phase dispersion: Thermodynamic calculation, microstructure, and interfacial reaction

    Science.gov (United States)

    Takaku, Yoshikazu; Ohnuma, Ikuo; Kainuma, Ryosuke; Yamada, Yasushi; Yagi, Yuji; Nishibe, Yuji; Ishida, Kiyohito

    2006-11-01

    Bismuth and its alloys are candidates for Pb-free high-temperature solders that can be substituted for conventional Pb-rich Pb-Sn solders (melting point (mp) = 573 583 K). However, inferior properties such as brittleness and weak bonding strength should be improved for practical use. To that end, BiCu-X (X=Sb, Sn, and Zn) Pb-free high-temperature solders are proposed. Miscibility gaps in liquid BiCu-X alloys were surveyed using the thermodynamic database ADAMIS (alloy database for micro-solders), and compositions of the BiCu-X solders were designed on the basis of calculation. In-situ composite solders that consist of a Bi-base matrix with fine intermetallic compound (IMC) particles were produced by gas-atomizing and melt-spinning methods. The interfacial reaction between in-situ composite solders and Cu or Ni substrates was investigated. The IMCs at the interface formed a thin, uniform layer, which is an appropriate morphology for a reliable solder joint.

  18. Microstructural and mechanical properties of binary Ni–Si eutectic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gogebakan, Musa, E-mail: gogebakan@ksu.edu.tr [Department of Physics, Faculty of Art and Sciences, Kahramanmaras Sutcu Imam University, Kahramanmaras 46100 (Turkey); Kursun, Celal [Department of Physics, Faculty of Art and Sciences, Kahramanmaras Sutcu Imam University, Kahramanmaras 46100 (Turkey); Gunduz, Kerem Ozgur; Tarakci, Mehmet; Gencer, Yucel [Department of Materials Science and Engineering, Gebze Institute of Technology, Gebze, 41400 Kocaeli (Turkey)

    2015-09-15

    Highlights: • Ni{sub 80}Si{sub 20}, Ni{sub 70}Si{sub 30}, Ni{sub 55}Si{sub 45} and Ni{sub 45}Si{sub 55} were prepared by arc melting method. • The maximum microhardness value of 1126 HV obtained for Ni{sub 70}Si{sub 30} alloy. • The microhardness values decreases with increase of Si/Ni ratio. • Ni{sub 80}Si{sub 20} and Ni{sub 55}Si{sub 45} are soft ferromagnetic, Ni{sub 70}Si{sub 30} and Ni{sub 45}Si{sub 55} are paramagnetic. - Abstract: In the present work, Ni–Si eutectic alloys with nominal compositions of Ni{sub 80}Si{sub 20}, Ni{sub 70}Si{sub 30}, Ni{sub 55}Si{sub 45} and Ni{sub 45}Si{sub 55} (Ni and Si with the purity of 99.99%) were prepared by arc melting method under vacuum/argon atmosphere. The effects of Si/Ni ratio on the microstructural properties, thermal transformation behavior, micro-hardness and magnetic properties of the Ni–Si eutectic alloys were investigated. These alloys were characterized by X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM), differential thermal analysis (DTA), Vickers microhardness measurement and Vibrating Sample Magnetometer (VSM). The phases expected according to Ni–Si phase diagram for conventional solidified eutectic Ni–Si alloys are considerably consistent with phase detected by XRD in this study. The quantitative results confirm that the chemical composition of the alloys very close to eutectic compositions and the microstructures are in typical lamellar eutectic morphology. The maximum microhardness value of 1126 HV obtained for Ni{sub 70}Si{sub 30} alloy which has highest melting temperature amongst Ni–Si eutectics. The microhardness values decreases with increase of Si/Ni ratio. Ni{sub 80}Si{sub 20} and Ni{sub 55}Si{sub 45} alloys are soft ferromagnetic, Ni{sub 70}Si{sub 30} and Ni{sub 45}Si{sub 55} alloys are paramagnetic with no magnetic saturation.

  19. Corrosion behavior of austenitic and ferritic/martensitic steels in oxygen-saturated liquid Pb-Bi eutectic at 450circC and 550circC

    OpenAIRE

    倉田 有司; 二川 正敏; 斎藤 滋

    2005-01-01

    Static corrosion tests of various austenitic and ferritic/martensitic steels were conducted in oxygen-saturated liquid Pb-Bi at 450circC and 550circC for 3000h to study the effects of temperature and alloying elements on corrosion behavior. Oxidation, grain boundary corrosion, dissolution and penetration were observed. The corrosion depth decreases at 450circC with increasing Cr content in steels regardless of ferritic/martensitic or austenitic steels. Appreciable dissolution of Ni and Cr doe...

  20. Laser soldering of Sn-Ag-Cu and Sn-Zn-Bi lead-free solder pastes

    Science.gov (United States)

    Takahashi, Junichi; Nakahara, Sumio; Hisada, Shigeyoshi; Fujita, Takeyoshi

    2004-10-01

    It has reported that a waste of an electronics substrate including lead and its compound such as 63Sn-37Pb has polluted the environment with acid rain. For that environment problem the development of lead-free solder alloys has been promoted in order to find out the substitute for Sn-Pb solders in the United States, Europe, and Japan. In a present electronics industry, typical alloys have narrowed down to Sn-Ag-Cu and Sn-Zn lead-free solder. In this study, solderability of Pb-free solder that are Sn-Ag-Cu and Sn-Zn-Bi alloy was studied on soldering using YAG (yttrium aluminum garnet) laser and diode laser. Experiments were peformed in order to determine the range of soldering parameters for obtaining an appropriate wettability based on a visual inspection. Joining strength of surface mounting chip components soldered on PCB (printed circuit board) was tested on application thickness of solder paste (0.2, 0.3, and 0.4 mm). In addition, joining strength characteristics of eutectic Sn-Pb alloy and under different power density were examined. As a result, solderability of Sn-Ag-Cu (Pb-free) solder paste are equivalent to that of coventional Sn-Pb solder paste, and are superior to that of Sn-Zn-Bi solder paste in the laser soldering method.

  1. Prediction of phase equilibria and thermal analysis in the Bi-Cu-Pb ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Manasijevic, Dragan [University of Belgrade, Technical Faculty, VJ 12, 19210 Bor (Serbia); Mitovski, Aleksandra, E-mail: amitovski@tf.bor.ac.rs [University of Belgrade, Technical Faculty, VJ 12, 19210 Bor (Serbia); Minic, Dusko [University of Pristina, Faculty of Technical Sciences, 38220 Kosovska Mitrovica (Serbia); Zivkovic, Dragana; Marjanovic, Sasa [University of Belgrade, Technical Faculty, VJ 12, 19210 Bor (Serbia); Todorovic, Radisa [Institute of Mining and Metallurgy, Zeleni Bulevar 35, 19210 Bor (Serbia); Balanovic, Ljubisa [University of Belgrade, Technical Faculty, VJ 12, 19210 Bor (Serbia)

    2010-05-20

    The knowledge about phase diagram of the Bi-Cu-Pb ternary system is of importance in development of copper-lead based bearing materials, soldering and in refining of copper and lead. In this work, the phase diagram of the Bi-Cu-Pb ternary system was calculated by the CALPHAD method using binary thermodynamic parameters included in the COST 531 database. The results include liquidus projection, invariant equilibria and three vertical sections with molar ratio Cu:Pb = 1, Cu:Pb = 1:3 and Bi:Cu = 1. Alloys, with compositions along three predicted vertical sections, were measured using differential scanning calorimetry (DSC). The experimentally determined phase transition temperatures were compared with calculated results and good mutual agreement was noticed.

  2. Prediction of phase equilibria and thermal analysis in the Bi-Cu-Pb ternary system

    International Nuclear Information System (INIS)

    Manasijevic, Dragan; Mitovski, Aleksandra; Minic, Dusko; Zivkovic, Dragana; Marjanovic, Sasa; Todorovic, Radisa; Balanovic, Ljubisa

    2010-01-01

    The knowledge about phase diagram of the Bi-Cu-Pb ternary system is of importance in development of copper-lead based bearing materials, soldering and in refining of copper and lead. In this work, the phase diagram of the Bi-Cu-Pb ternary system was calculated by the CALPHAD method using binary thermodynamic parameters included in the COST 531 database. The results include liquidus projection, invariant equilibria and three vertical sections with molar ratio Cu:Pb = 1, Cu:Pb = 1:3 and Bi:Cu = 1. Alloys, with compositions along three predicted vertical sections, were measured using differential scanning calorimetry (DSC). The experimentally determined phase transition temperatures were compared with calculated results and good mutual agreement was noticed.

  3. Interaction of alumina with liquid Pb{sub 83}Li{sub 17} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Uttam, E-mail: uttamj@barc.gov.in [Fusion Reactor Materials Section, Bhabha Atomic Research Centre, Mumbai 400085 (India); Mukherjee, Abhishek; Sonak, Sagar; Kumar, Sanjay [Fusion Reactor Materials Section, Bhabha Atomic Research Centre, Mumbai 400085 (India); Mishra, Ratikant [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Krishnamurthy, Nagaiyar [Fusion Reactor Materials Section, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2014-11-15

    Highlights: • The role of oxygen in the interaction of alumina with Pb{sub 83}Li{sub 17} alloy was studied. • Li of Pb{sub 83}Li{sub 17} alloy undergoes oxidation even in flowing high pure argon atmosphere. • It was seen that alumina reacts with Pb{sub 83}Li{sub 17} alloy at 550 °C to form LiAlO{sub 2} compound. • The reaction is rapid in the presence of oxygen and happens more slowly in the presence of flowing argon. - Abstract: Eutectic lead lithium (Pb{sub 83}Li{sub 17}) alloy is being considered a coolant, neutron multiplier and tritium breeder for International Thermonuclear Experimental Reactor (ITER) and Fusion Power Reactors (FPR). In order to reduce the magneto-hydrodynamic drag (MHD) and to prevent corrosion of structural materials due to the flow of lead lithium (Pb{sub 83}Li{sub 17}) alloy, alumina (Al{sub 2}O{sub 3}) is proposed as a candidate ceramic coating material. Interaction of liquid Pb{sub 83}Li{sub 17} alloy with Al{sub 2}O{sub 3} at the operating temperature of these reactors is therefore an important issue. The present paper deals with the characterization of Pb{sub 83}Li{sub 17} alloy and its interaction with Al{sub 2}O{sub 3} at the reactor operating temperature. The interaction was studied using EPMA, XRD and thermal analysis technique. The result indicates that alumina can interact with Pb{sub 83}Li{sub 17} alloy at 550 °C even in high purity argon atmosphere. The role of oxygen in the interaction process has also been discussed.

  4. Modification mechanism of eutectic silicon in Al–6Si–0.3Mg alloy with scandium

    Energy Technology Data Exchange (ETDEWEB)

    Patakham, Ussadawut [Manufacturing and Systems Engineering Program, Department of Production Engineering, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, 126 Pracha-Utid Rd., Bangmod, Tungkhru, Bangkok 10140 (Thailand); Kajornchaiyakul, Julathep [National Metal and Material Technology Center, National Science and Technology Development Agency, 114 Thailand Science Park, Klong Nueng, Klong Luang, Pathumthani 12120 (Thailand); Limmaneevichitr, Chaowalit, E-mail: chaowalit.lim@kmutt.ac.th [Manufacturing and Systems Engineering Program, Department of Production Engineering, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, 126 Pracha-Utid Rd., Bangmod, Tungkhru, Bangkok 10140 (Thailand)

    2013-10-25

    Highlights: •Morphologies and growth of Sc and Sr-modified eutectic silicon resemble those of dendrites. •Crystal orientation of eutectic aluminum depends on growth characteristics of eutectic silicon. •We report strong evidence of the occurrence of an impurity-induced twinning mechanism. -- Abstract: The modification mechanism of eutectic silicon in Al–6Si–0.3Mg alloy with scandium was studied. The crystallographic orientation relationships between primary dendrites and the eutectic phase of unmodified and modified Al–6Si–0.3 Mg alloys were determined using electron backscatter diffraction (EBSD). The orientation of aluminum modified with scandium in the eutectic phase was different from that of the neighboring primary dendrites. This result implies that eutectic aluminum grows epitaxially from the surrounding primary aluminum dendrites in the unmodified alloy and that eutectic aluminum grows competitively from the surrounding primary aluminum dendrites in the modified alloy. The pole figure maps of eutectic Si in the [1 0 0], [1 1 0] and [1 1 1] axes of the unmodified and Sc-modified alloys were different, suggesting that the eutectic Al and Si crystals in modified alloy growth are more isotropic and cover a larger set of directions. The lattice fringes of Si of the alloys with and without Sc modification were different in the TEM results. The lattice fringes of Si in modified alloy were found to be multiple twins. However, this was not observed in the unmodified alloy. The growth characteristic of eutectic Si crystal in modified alloy suggests the occurrence of multiple twinning reactions and the formation of a high density of twins. This modification mechanism by Sc is explained by the results of scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) analysis, which provide strong evidence of the occurrence of the impurity-induced twinning (IIT) mechanism.

  5. Containerless solidification of acoustically levitated Ni-Sn eutectic alloy

    Energy Technology Data Exchange (ETDEWEB)

    Geng, D.L.; Xie, W.J.; Wei, B. [Northwestern Polytechnical University, Department of Applied Physics, Xi' an (China)

    2012-10-15

    Containerless solidification of Ni-18.7at%Sn eutectic alloy has been achieved with a single-axis acoustic levitator. The temperature, motion, and oscillation of the sample were monitored by a high speed camera. The temperature of the sample can be determined from its image brightness, although the sample moves vertically and horizontally during levitation. The experimentally observed frequency of vertical motion is in good agreement with theoretical prediction. The sample undergoes shape oscillation before solidification finishes. The solidification microstructure of this alloy consists of a mixture of anomalous eutectic plus regular lamellar eutectic. This indicates the achievement of rapid solidification under acoustic levitation condition. (orig.)

  6. Organic alloy systems suitable for the investigation of regular binary and ternary eutectic growth

    Science.gov (United States)

    Sturz, L.; Witusiewicz, V. T.; Hecht, U.; Rex, S.

    2004-09-01

    Transparent organic alloys showing a plastic crystal phase were investigated experimentally using differential scanning calorimetry and directional solidification with respect to find a suitable model system for regular ternary eutectic growth. The temperature, enthalpy and entropy of phase transitions have been determined for a number of pure substances. A distinction of substances with and without plastic crystal phases was made from their entropy of melting. Binary phase diagrams were determined for selected plastic crystal alloys with the aim to identify eutectic reactions. Examples for lamellar and rod-like eutectic solidification microstructures in binary systems are given. The system (D)Camphor-Neopentylglycol-Succinonitrile is identified as a system that exhibits, among others, univariant and a nonvariant eutectic reaction. The ternary eutectic alloy close to the nonvariant eutectic composition solidifies with a partially faceted solid-liquid interface. However, by adding a small amount of Amino-Methyl-Propanediol (AMPD), the temperature of the nonvariant eutectic reaction and of the solid state transformation from plastic to crystalline state are shifted such, that regular eutectic growth with three distinct nonfaceted phases is observed in univariant eutectic reaction for the first time. The ternary phase diagram and examples for eutectic microstructures in the ternary and the quaternary eutectic alloy are given.

  7. Prospects for designing structural cast eutectic alloys on Al-Ce-Ni system base

    International Nuclear Information System (INIS)

    Belov, N.A.; Naumova, E.S.

    1996-01-01

    The phase diagram of Al-Ce-Ni system is built for an aluminium corner at component concentration up to 16 mass %Ce and 8 mass%Ni. A ternary eutectic reaction is established at 12%Ce, 5%Ni and 626 deg C. The ternary eutectic alloy is similar in structure to rapidly cooled Al base alloys with transition metals. The possibility to design new cast alloys based on three-phase (Al)+NiAl 3 +CeAl 4 eutectics is under consideration. Al-Zn-Mg-Cu, Al-Sc and Al-Zr base alloys can be used as (Al) constituent of the eutectics. The new alloys may be considered as heat resistant ones due to the fact that no structural changes are observed in castings on heating up to 350 deg C. 18 refs.; 4 figs.; 2 tabs

  8. The inhomogeneities of (Pb,Bi)2223 superconducting tapes and their detection

    International Nuclear Information System (INIS)

    Leeuwen, S. van

    1999-05-01

    This thesis consists of two parts: first, the inhomogeneities that were observed in high temperature superconducting (Pb,Bi)2223 tapes were studied followed by the design of two rigs which were built to detect them. These investigations concentrated on (Pb,Bi)2223 phase high temperature superconducting tapes. Superconductors and their applications were briefly evaluated. It was found that high temperature superconductors have unique properties which cannot be duplicated by their counterparts. However, it was noted that there are significant improvements to be made before they can be commercially viable. An investigation was carried out into the variation of core density within cross sections and along lengths of (Pb,Bi)2223 tapes during fabrication. It was observed that rolling and thermal treatment brought about a non-uniform core density in both these aspects of tile tape. This was followed by an investigation into the effect of core density on the formation of the (Pb,Bi)2223 phase. It was shown that a high core density formed the (Pb,Bi)2223 phase at a slower rate than a lower core density under the thermal treatment. A high core density and a slow heating rate produced smaller 2212 grains at the end of the incubation period. Smaller 2212 grains were thought to be linked to the faster formation of the (Pb,B1)2223 phase. The highest Jc was from a high core density tape which had the smaller 2212 grains at the end of incubation period. Smaller 2212 grains were thought to aid a more homogeneous conversion to the (Pb,Bi)2223 phase. Alloy-sheathed (Pb,Bi)2223 superconducting tapes were produced in order to fabricate a more homogeneous core density. It was found that the alloy sheath (with an addition of 15% wt Ag in the precursor powder) changed the characteristics of the core in several ways: the formation of the (Pb,Bi)2223 phase was homogeneous across the thickness of the core, a smaller 2212 grain size was formed at the end of the incubation period and a higher

  9. The solubility of metals in Pb-17Li liquid alloy

    International Nuclear Information System (INIS)

    Borgstedt, H.U.; Feuerstein, H.

    1992-01-01

    The solubility data of iron in the eutectic alloy Pb-17Li which were evaluated from corrosion tests in a turbulent flow of the molten alloy are discussed in the frame of solubilities of the transition metals in liquid lead. It is shown that the solubility of iron in the alloy is close to that in lead. This is also the fact for several other alloying elements of steels. A comparison of all known data shows that they are in agreement with generally shown trends for the solubility of the transition metals in low melting metals. These trends indicate comparably high solubilities of nickel and manganese in the liquid metals, lower saturation concentration of vanadium, chromium, iron, and cobalt, and extremely low solubility of molybdenum. (orig.)

  10. Antimony Influence on Shape of Eutectic Silicium in Al-Si Based Alloys

    Directory of Open Access Journals (Sweden)

    Bolibruchová D.

    2017-12-01

    Full Text Available Liquid AI-Si alloys are usually given special treatments before they are cast to obtain finer or modified matrix and eutectic structures, leading to improved properties. For many years, sodium additions to hypoeutectic and eutectic AI-Si melts have been recognized as the most effective method of modifying the eutectic morphology, although most of the group IA or IIA elements have significant effects on the eutectic structure. Unfortunately, many of these approaches also have associated several founding difficulties, such as fading, forming dross in presence of certain alloying elements, reduced fluidity, etc. ln recent years, antimony additions to AI-Si castings have attracted considerable attention as an alternative method of refining the eutectic structure. Such additions eliminate many of the difficulties listed above and provide permanent (i.e. non-fading refining ability. In this paper, the authors summarize work on antimony treatment of Al-Si based alloys.

  11. Tl, Bi, and Pb doping in Ba4BiPb2TlO12-δ

    International Nuclear Information System (INIS)

    Sutto, T.E.; Averill, B.A.

    1992-01-01

    To determine the effects of different 6s metal concentrations on the superconducting nature of Ba 4 BiPb 2 TlO 12-δ , materials produced via four doping schemes were examined: Ba 4 Bi(Pb, Tl) 3 O 12-δ , Ba 4 -(BiPb) 3 TlO 12-δ , Ba 4 (Bi,Tl) 2 Pb 2 O 12-δ , and Ba 4 Bi x Pb 4-2x Tl x O 12-δ . For the parent compound a value of δ = 0.91 was observed, indicating that approximately 1/4 oxygen atom was missing per cubic subsection of the unit cell. For all samples, the symmetry of the parent compound changed from orthorhombic to tetragonal as the system moved away from the ideal composition. This was usually accompanied by the loss of superconductivity, which exhibited a maximum T c of 10.5 K for the parent compound Ba 4 BiPb 2 TlO 12-δ . Also reported are high-temperature magnetic susceptibility results, which are used to determine the effect of metal substitution on the density of states at the Fermi level. For each set of variants on the parent composition, the onset of superconductivity was accompanied by a significant decrease in the size of the Pauli paramagnetic signal. 16 refs., 6 figs

  12. Effect of Bi-content on hardness and micro-creep behavior of Sn-3.5Ag rapidly solidified alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kamal, M. [Metal Physics Laboratory, Faculty of Science, Mansoura University (Egypt); Gouda, El Said [Metal Physics Laboratory, Department of Solid State Physics, Physics Division, National Research Center, Dokki, Giza (Egypt); Marei, L.K. [Faculty of Petroleum and Mining Engineering, Suez Canal University, Suez (Egypt)

    2009-12-15

    In the present paper, the influence of 1, 3, 5 and 10 % Bi (weight %) as ternary additions on structure, melting and mechanical properties of rapidly solidified Sn-3.5Ag alloy has been investigated. The effect of Bi was discussed based on the experimental results. The experimental results showed that the alloys of Sn-3.5Ag, Sn-3.5Ag-1Bi and Sn-3.5Ag-3Bi are composed of two phases; Ag{sub 3}Sn IMC embedded in Sn matrix phase, which indicated that the solubility of Bi phase in Sn-matrix was extended to 3 % as a result of rapid solidification. Bi precipitation in Sn matrix was only observed in Sn-3.5Ag-5Bi and Sn-3.5Ag-10Bi alloys. Also, addition of Bi decreased continuously the melting point of the eutectic Sn-3.5Ag alloy to 202.6 C at 10 % Bi. Vickers hardness of Sn-3.5Ag rapidly solidified alloy increased with increasing Bi content up to 3 % due to supersaturated solid solution strengthening hardening mechanism of Bi phase in Sn matrix, while the alloys contain 5 and 10 % Bi exhibited lower values of Vickers hardness. The lower values can be attributed to the precipitation of Bi as a secondary phase which may form strained regions due to the embrittlement of Bi atom. In addition, the effect of Bi addition on the micro-creep behavior of Sn-3.5Ag alloy as well as the creep rate have been described and has been calculated at room temperature. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Response of MnBi-Bi eutectic to freezing rate changes

    Science.gov (United States)

    Nair, M.; Fu, T.-W.; Wilcox, W. R.; Doddi, K.; Ravishankar, P. S.; Larson, D.

    1982-01-01

    Reference is made to a study by Fu and Wilcox (1981), which treated theoretically the influence on freezing rate of sudden changes in translation rate in the Bridgman-Stockbarger technique. This treatment is extended here to a linear ramped translation rate and an oscillatory freezing rate. It is found that oscillations above a few hertz are highly damped in small-diameter apparatus. An experimental test is carried out of the theoretical predictions for a sudden change of translation rate. The MnBi-Bi eutectic is solidified with current-induced interface demarcation. The experimental results accord reasonably well with theory if the silica ampoule wall is assumed to either (1) contribute only a resistance to heat exchange between the sample and the furnace wall or (2) transmit heat effectively in the axial direction by radiation. In an attempt to explain the fact that a finer microstructure is obtained in space, MnBi-Bi microstructure is determined when the freezing rate is increased or decreased rapidly. Preliminary results suggest that fiber branching does not occur as readily as fiber termination.

  14. Phase state of a Bi-43 wt % Sn superplastic alloy and its changes under the effect of external mechanical stresses and aging

    Science.gov (United States)

    Korshak, V. F.; Chushkina, R. A.; Shapovalov, Yu. A.; Mateichenko, P. V.

    2011-07-01

    Samples of a Bi-43 wt % Sn superplastic alloy have been studied by X-ray diffraction in the ascast state, after compression of as-cast samples to ˜70% on a hydraulic press, after aging in the as-cast and preliminarily compressed state, and using samples deformed under superplastic conditions. The X-ray diffraction studies have been carried out using a DRON-2.0 diffractometer in Cu Kα radiation. The samples aged and deformed under superplasticity conditions have been studied using electron-microprobe analysis in a JSM-820 scanning electron microscope equipped with a LINK AN/85S EDX system. It has been found that the initial structural-phase state of the alloy was amorphous-crystalline. Causes that lead to a change in this state upon deformation and aging are discussed. A conclusion is made that the superplasticity effect manifests itself against the background of processes that are stipulated by the tendency of the initially metastable alloy to phase equilibrium similarly to what is observed in the Sn-38 wt % Pb eutectic alloy studied earlier.

  15. Effect of Low-Melting Metals (Pb, Bi, Cd, In) on the Structure, Phase Composition, and Properties of Casting Al-5% Si-4% Cu Alloy

    Science.gov (United States)

    Yakovleva, A. O.; Belov, N. A.; Bazlova, T. A.; Shkalei, I. V.

    2018-01-01

    The effect of low-melting metals (Pb, Bi, Cd, In) on the structure, phase composition, and properties of the Al-5% Si-4% Cu alloy was studied using calculations. Polythermal sections have been reported, which show that the considered systems are characterized by the presence of liquid regions and monotectic reactions. The effect of low-melting metals on the microstructure and hardening of base alloy in the cast and heat-treated states has been studied.

  16. Calorimetric investigation of Pb-Bi system

    International Nuclear Information System (INIS)

    Agarwal, Renu; Jat, Ram Avtar; Sen, B.K.

    2008-01-01

    Enthalpy increment of Pb 0.71 Bi 0.29 compound was determined using high temperature Calvet calorimeter. The data was fit into the following polynomial equation. ΔH(T-298.15 K) J/mol = -10384.96 + 39.23 T - 0.014T 2 - 18970/T. By precipitation method, the enthalpy of formation of the compound of composition Pb 0.68 Bi 0.32 at 448 K, from Pb(l) and Bi(l) was determined to be -2450± 50 J/mol and from Pb(s) and Bi(s) at 298.15 K was calculated to be 4047 J/mol. (author)

  17. Role of bismuth on solidification, microstructure and mechanical properties of a near eutectic Al-Si alloys

    Science.gov (United States)

    Farahany, Saeed; Ourdjini, Ali; Bakar, Tuty Asma Abu; Idris, Mohd Hasbullah

    2014-09-01

    Computer aided thermal analysis and microstructural observation showed that addition of bismuth (Bi) within the range of 0.25 and 2 wt% produced a greater effect on the Al-Si eutectic phase than on primary aluminium and Al2Cu phases. Results showed that with addition of 1 wt% Bi the eutectic silicon structure was refined from flake-like morphology into lamellar. Bi refines rather than modifies the Si structure and increases the Al-Si eutectic fraction solid and more significantly there was no fading even up to 180 min of melt holding. Transmission electron microscopy study showed that the Si twin spacing decreased from 160 to 75 nm which is likely attributed to the refining effect of Bi. It was also found that addition of 1 wt% Bi increased the tensile strength, elongation and the absorbed energy for fracture due to the refined eutectic silicon structure.

  18. Eutectic growth under acoustic levitation conditions.

    Science.gov (United States)

    Xie, W J; Cao, C D; Lü, Y J; Wei, B

    2002-12-01

    Samples of Pb-Sn eutectic alloy with a high density of 8.5 x 10(3) kg/m(3) are levitated with a single-axis acoustic levitator, and containerlessly melted and then solidified in argon atmosphere. High undercoolings up to 38 K are obtained, which results in a microstructural transition of "lamellas-broken lamellas-dendrites." This transition is further investigated in the light of the coupled zone for eutectic growth and the effects of ultrasound. The breaking of regular eutectic lamellas and suppression of gravity-induced macrosegregation of (Pb) and (Sn) dendrites are explained by the complicated internal flow inside the levitated drop, which is jointly induced by the shape oscillation, bulk vibration and rotation of the levitated drop. The ultrasonic field is also found to drive forced surface vibration, which subsequently excites capillary ripples and catalyzes nucleation on the sample surface.

  19. Corrosion behavior of Al-Fe-sputtering-coated steel, high chromium steels, refractory metals and ceramics in high temperature Pb-Bi

    International Nuclear Information System (INIS)

    Abu Khalid, Rivai; Minoru, Takahashi

    2007-01-01

    Corrosion tests of Al-Fe-coated steel, high chromium steels, refractory metals and ceramics were carried out in high temperature Pb-Bi at 700 C degrees. Oxygen concentrations in this experiment were 6.8*10 -7 wt.% for Al-Fe-coated steels and 5*10 -6 wt.% for high chromium steels, refractory metals and ceramics. All specimens were immersed in molten Pb-Bi in a corrosion test pot for 1.000 hours. Coating was done with using the unbalanced magnetron sputtering (UBMS) technique to protect the steel from corrosion. Sputtering targets were Al and SUS-304. Al-Fe alloy was coated on STBA26 samples. The Al-Fe alloy-coated layer could be a good protection layer on the surface of steel. The whole of the Al-Fe-coated layer still remained on the base surface of specimen. No penetration of Pb-Bi into this layer and the matrix of the specimen. For high chromium steels i.e. SUS430 and Recloy10, the oxide layer formed in the early time could not prevent the penetration of Pb-Bi into the base of the steels. Refractory metals of tungsten (W) and molybdenum (Mo) had high corrosion resistance with no penetration of Pb-Bi into their matrix. Penetration of Pb-Bi into the matrix of niobium (Nb) was observed. Ceramic materials were SiC and Ti 3 SiC 2 . The ceramic materials of SiC and Ti 3 SiC 2 had high corrosion resistance with no penetration of Pb-Bi into their matrix. (authors)

  20. Perspectives for tritium recovery from liquid Pb83Li17 alloy

    International Nuclear Information System (INIS)

    Pierini, G.

    1983-01-01

    A preliminary analysis has been made on the perspectives of tritium recovery from a blanket constituted by liquid Pb 83 Li 17 alloy, by investigating the Tsub(2g) 2T alloy thermodynamic behaviour and trying to individuate those chemico-physical characteristics of which knowledge is useful for the effective design of the apparatus. In the light of the recent work carried out on the systems, hydrogen and its isotopes with molten Li-Pb eutectics, it has been possible to individuate a fair reliability of the Sieverts constant for the T 2 -Pb 83 Li 17 system. As far as the kinetics of the tritium desorption process from the liquid phase are concerned, the hydrogen (and its isotopes) transfer rates across the liquid interphase have been evaluated. Even though in first approximation the diffusion coefficient of tritium in the molten alloy at 400 0 C has been found. Then, the processing equations of attractive tritium recovery systems have been presented, individuating the fundamental parameters and reporting an example of applied engineering of the desorption system in a packed column. None of these tritium recovery systems seem incompatible at the actual state of the research

  1. Structural perfection of directionally solidified lamellar eutectics

    International Nuclear Information System (INIS)

    Attallah, T.; Gurzleski, J.E.

    1976-01-01

    The mechanisms for the formation of faults in lamellar eutectics are reviewed, and it is postulated that faults play several roles in eutectic freezing with their exact importance depending on the specific alloy system and the growth conditions. Faults are not the cause of lamellar spiralling although they are necessary for it to occur. Lamellar spiralling is found to occur only when the crystallographic orientations of the two eutectic phases lead to a growth component normal to the lamellar plane, and although some systems such as Pb-Sn normally spiral it is possible for them to achieve orientation relationships where no spiralling occurs

  2. Effect of scandium on structure and hardening of Al–Ca eutectic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Belov, N.A., E-mail: nikolay-belov@yandex.ru [National Research and Technological University “MISIS”, 4, Leninsky pr., Moscow 119049 (Russian Federation); Naumova, E.A. [Bauman Moscow State Technical University, 5, 2 ul. Baumanskaya, Moscow, 105005 (Russian Federation); Alabin, A.N. [National Research and Technological University “MISIS”, 4, Leninsky pr., Moscow 119049 (Russian Federation); UC RUSAL, 13/1, Nikoloyamskaya st., Moscow, 109240 (Russian Federation); Matveeva, I.A. [UC RUSAL, 13/1, Nikoloyamskaya st., Moscow, 109240 (Russian Federation)

    2015-10-15

    The phase composition, structure and hardening of alloys in the aluminium corner of the Al–Ca–Sc system were studied in the range up to 10% Ca and up to 1% S≿. The experimental study (optical, scanning and transmission electron microscopy with electron-microprobe analysis, differential thermal analysis and hardness measurements) was combined with Thermo-Calc software simulation for the optimization of the alloy composition. It was shown that only phases of the binary systems (Al{sub 4}Ca and Al{sub 3}Sc) might be in equilibrium with the aluminium solid solution. It was shown that the (Al) + Al{sub 4}Ca eutectic had a much finer structure as compared with the Al–Si eutectic, which suggests a possibility of reaching higher mechanical properties as compared to commercial alloys of the A356 type. The influence of the annealing temperature within the range up to 600 °C on the structure and hardness of the Al–Ca–Sc experimental alloys was studied. It was determined that the maximum hardening corresponded to the annealing at 300 °C, which was due to the precipitation of Al{sub 3}Sc nanoparticles with their further coarsening. With an example of an Al-7.6% Ca-0.3% Sc model experimental alloy, a principal possibility of manufacturing aluminium casting alloys based on the (Al) + Al{sub 4}Ca eutectic was demonstrated. Unlike commercial alloys of the A356 type, the model alloy does not require quenching, as hardening particles are formed in the course of annealing of casting. - Highlights: • Al–Ca–Sc phase diagram in aluminum corner. • Formation of Al{sub 3}Sc nanoparticles in eutectic (Al) + Al{sub 4}Ca during heating at 300–450 °C. • Hardening and thermal stability of proposed (Al–Ca–Sc) and commercial (Al–Si–Mg, 356 type) eutectic alloys.

  3. Eutectic structures in friction spot welding joint of aluminum alloy to copper

    International Nuclear Information System (INIS)

    Shen, Junjun; Suhuddin, Uceu F. H.; Cardillo, Maria E. B.; Santos, Jorge F. dos

    2014-01-01

    A dissimilar joint of AA5083 Al alloy and copper was produced by friction spot welding. The Al-MgCuAl 2 eutectic in both coupled and divorced manners were found in the weld. At a relatively high temperature, mass transport of Cu due to plastic deformation, material flow, and atomic diffusion, combined with the alloy system of AA5083 are responsible for the ternary eutectic melting

  4. Electronic tuning of the transport properties of off-stoichiometric Pb{sub x}Sn{sub 1−x}Te thermoelectric alloys by Bi{sub 2}Te{sub 3} doping

    Energy Technology Data Exchange (ETDEWEB)

    Guttmann, Gilad M. [The Unit of Energy Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel); Dadon, David [Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel); Gelbstein, Yaniv [The Unit of Energy Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel); Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel)

    2015-08-14

    The recent energy demands affected by the dilution of conventional energy resources and the growing awareness of environmental considerations had motivated many researchers to seek for novel renewable energy conversion methods. Thermoelectric direct conversion of thermal into electrical energies is such a method, in which common compositions include IV-VI semiconducting compounds (e.g., PbTe and SnTe) and their alloys. For approaching practical thermoelectric devices, the current research is focused on electronic optimization of off-stoichiometric p-type Pb{sub x}Sn{sub 1−x}Te alloys by tuning of Bi{sub 2}Te{sub 3} doping and/or SnTe alloying levels, while avoiding the less mechanically favorable Na dopant. It was shown that upon such doping/alloying, higher ZTs, compared to those of previously reported undoped Pb{sub 0.5}Sn{sub 0.5}Te alloy, were obtained at temperatures lower than 210–340 °C, depending of the exact doping/alloying level. It was demonstrated that upon optimal grading of the carrier concentration, a maximal thermoelectric efficiency enhancement of ∼38%, compared to that of an undoped material, is expected.

  5. Effects of Eutectic Si Particles on Mechanical Properties and Fracture Toughness of Cast A356 Aluminum Alloys

    International Nuclear Information System (INIS)

    Lee, Kyu Hong; Lee, Sung Hak; Kwon, Yong Nam

    2007-01-01

    The present study aims at investigating the effects of eutectic Si particles on mechanical properties and fracture toughness of three A356 aluminum alloys. These A356 alloys were fabricated by casting processes such as rheo-casting, squeeze-casting, and casting-forging, and their mechanical properties and fracture toughness were analyzed in relation with microfracture mechanism study. All the cast A356 alloys contained eutectic Si particles mainly segregated along solidification cells, and the distribution of Si particles was modified by squeeze-casting and casting-forging processes. Microfracture observation results showed that eutectic Si particles segregated along cells were cracked first, but that aluminum matrix played a role in blocking crack propagation. Tensile properties and fracture toughness of the squeeze cast and cast-forged alloys having homogeneous distribution of eutectic Si particles were superior to those of the rheo-cast alloy. In particular, the cast-forged alloy had excellent hardness, strength, ductility, and fracture toughness because of the matrix strengthening and homogeneous distribution of eutectic Si particles due to forging process

  6. Thermodynamic properties and equation of state of liquid lead and lead bismuth eutectic

    Science.gov (United States)

    Sobolev, V. P.; Schuurmans, P.; Benamati, G.

    2008-06-01

    Since the 1950s, liquid lead (Pb) and lead-bismuth eutectic (Pb-Bi) have been studied in the USA, Canada and in the former-USSR as potential coolants for nuclear installations due to their very attractive thermophysical and neutronic properties. However, experimental data on the thermal properties of these coolants in the temperature range of interest are still incomplete and often contradictory. This makes it very difficult to perform design calculations and to analyse the normal and abnormal behaviour of nuclear installations where these coolants are expected to be used. Recently, a compilation of heavy liquid metal (HLM) properties along with recommendations for its use was prepared by the OECD/NEA Working Party on Fuel Cycle (WPFC) Expert Group on Lead-Bismuth Eutectic Technology. A brief review of this compilation and some new data are presented in this article. A set of correlations for the temperature dependence of the main thermodynamic properties of Pb and Pb-Bi(e) at normal pressure, and a set of simplified thermal and caloric equations of state for the liquid phase are proposed.

  7. Experimental and Theoretical Investigations of the Solidification of Eutectic Al-Si Alloy

    Science.gov (United States)

    Sen, S.; Catalina, A. V.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    The eutectic alloys have a wide spectrum of applications due to their good castability and physical and mechanical properties. The interphase spacing resulting during solidification is an important microstructural feature that significantly influences the mechanical behavior of the material. Thus, knowledge of the evolution of the interphase spacing during solidification is necessary in order to properly design the solidification process and optimize the material properties. While the growth of regular eutectics is rather well understood, the irregular eutectics such as Al-Si or Fe-graphite exhibit undercoolings and lamellar spacings much larger than those theoretically predicted. Despite of a considerable amount of experimental and theoretical work a clear understanding of the true mechanism underlying the spacing selection in irregular eutectics is yet to be achieved. A new experimental study of the solidification of the eutectic Al-Si alloy will be reported in this paper. The measured interface undercoolings and lamellar spacing will be compared to those found in the literature in order to get more general information regarding the growth mechanism of irregular eutectics. A modification of the present theory of the eutectic growth is also proposed. The results of the modified mathematical model, accounting for a non-isothermal solid/liquid interface, will be compared to the experimental measurements.

  8. Studies on the phase diagram of Pb-Mo-O system

    International Nuclear Information System (INIS)

    Aiswarya, P.M.; Ganesan, Rajesh; Gnanasekaran, T.

    2014-01-01

    Liquid lead and Lead-Bismuth Eutectic (LBE) alloy are considered as spallation target and coolant in the accelerator driven systems and as candidate coolant in advanced nuclear reactors. Corrosion of the structural steel components in these liquid metal coolants can be minimized by the insitu formation of passive oxide layer on the steel surface under controlled oxygen concentration. A detailed knowledge of phase diagrams of Pb-M-O and Bi-M-O (M = Fe, Cr, Mo) systems and data on thermochemical properties of the ternary compounds of these systems are required for better understanding of composition and stability of these passive oxide films. In the present work, studies have been carried out to establish the ternary phase diagram of Pb-Mo-O system

  9. The effect of the solidification mode on eutectic structure in Fe-C-V alloys

    International Nuclear Information System (INIS)

    Fras, E.; Guzik, E.

    1980-01-01

    The aim of the study was to determine such a chemical composition of Fe-C-V alloys which would ensure the formation of perfectly eutectic structures as well as to investigate the eutectic morphology of these alloys when undergoing bulk and directional solidification. Attempts have been done to get in situ composites from Fe-C-V alloys. The adopted testing methods as well as obtained results are described in detail. (H.M.)

  10. Divorced Eutectic Solidification of Mg-Al Alloys

    Science.gov (United States)

    Monas, Alexander; Shchyglo, Oleg; Kim, Se-Jong; Yim, Chang Dong; Höche, Daniel; Steinbach, Ingo

    2015-08-01

    We present simulations of the nucleation and equiaxed dendritic growth of the primary hexagonal close-packed -Mg phase followed by the nucleation of the -phase in interdendritic regions. A zoomed-in region of a melt channel under eutectic conditions is investigated and compared with experiments. The presented simulations allow prediction of the final properties of an alloy based on process parameters. The obtained results give insight into the solidification processes governing the microstructure formation of Mg-Al alloys, allowing their targeted design for different applications.

  11. Effect of Ni on eutectic structural evolution in hypereutectic Al-Mg2Si cast alloys

    International Nuclear Information System (INIS)

    Li Chong; Wu Yaping; Li Hui; Wu Yuying; Liu Xiangfa

    2010-01-01

    Research highlights: → By the injection of rod-like NiAl 3 phase in Al-Mg 2 Si alloys, Al-Mg 2 Si binary eutectic structure gradually evolves into Al-Mg 2 Si-NiAl 3 ternary eutectic. → The ternary eutectic presents a unique double rod structure that rod-like NiAl 3 and Mg 2 Si uniformly distribute in Al matrix. → The mechanism of structural evolution was analyzed in terms of the detailed microstructural observations. → The high temperature (350 deg. C) tensile strength of the alloy increases by 23% due to the eutectic structural evolution. - Abstract: The aim of this work is to investigate the eutectic structural evolution of hypereutectic Al-20% Mg 2 Si with Ni addition under a gravity casting process. Three-dimensional morphologies of eutectic phases were observed in detail using field emission scanning electron microscopy, after Al matrix was removed by deep etching or extraction. The results show that Al-Mg 2 Si binary eutectic gradually evolves into Al-Mg 2 Si-NiAl 3 ternary eutectic with the increase of Ni content, and flake-like eutectic Mg 2 Si transforms into rods. The ternary eutectic presents a unique double rod structure that rod-like NiAl 3 and Mg 2 Si uniformly distribute in Al matrix. Further, the high temperature (350 deg. C) tensile strength of the alloy increases by 23% due to the eutectic structure evolution, and the mechanism of structural evolution was discussed and analyzed in terms of the detailed microstructural observations.

  12. Behavior of 210Pb and 210Bi in soil-rice system and the effects of carrier-Pb

    International Nuclear Information System (INIS)

    Li Shuding

    1993-01-01

    Chemical species of 210 Pb and 210 Bi in soil and rice were investigated using 210 Pb trace experiment. 79%-91% of 210 Pb in the soil was in available fraction. On the contrary, 80%-98% of 210 Bi was bound. The available 210 Pb in the soil was changed slowly into bound fraction, while the bound 210 Bi transformed gradually into available one. Much of 210 Pb and 210 Bi entered into rice were as inorganic free ions. The bound 210 Pb in rice was less than 1% and the bound 210 Bi was around 40%. The different adsorption affinities between 210 Pb and 210 Bi were demonstrated by the different behavior of them. The effect of carrier-Pb on adsorption of 210 Pb and 210 Bi was also discussed

  13. Modeling of Eutectic Formation in Al-Si Alloy Using A Phase-Field Method

    Directory of Open Access Journals (Sweden)

    Ebrahimi Z.

    2017-12-01

    Full Text Available We have utilized a phase-field model to investigate the evolution of eutectic silicon in Al-Si alloy. The interfacial fluctuations are included into a phase-field model of two-phase solidification, as stochastic noise terms and their dominant role in eutectic silicon formation is discussed. We have observed that silicon spherical particles nucleate on the foundation of primary aluminum phase and their nucleation continues on concentric rings, through the Al matrix. The nucleation of silicon particles is attributed to the inclusion of fluctuations into the phase-field equations. The simulation results have shown needle-like, fish-bone like and flakes of silicon phase by adjusting the noise coefficients to larger values. Moreover, the role of primary Al phase on nucleation of silicon particles in Al-Si alloy is elaborated. We have found that the addition of fluctuations plays the role of modifiers in our simulations and is essential for phase-field modeling of eutectic growth in Al-Si system. The simulated finger-like Al phases and spherical Si particles are very similar to those of experimental eutectic growth in modified Al-Si alloy.

  14. Ga-Bi-Te system

    International Nuclear Information System (INIS)

    Rustamov, P.G.; Seidova, N.A.; Shakhbazov, M.G.; AN Azerbajdzhanskoj SSR, Baku. Inst. Neorganicheskoj i Fizicheskoj Khimii)

    1976-01-01

    To elucidate the nature of interaction in the system Ga-Bi-Te, a study has been made of sections GaTe-Bi 2 Te 3 , Ga 2 Te 3 -Bi, GaTe-Bi and Bi 2 Te 3 -Ga. The alloys have been prepared by direct melting of the components or their alloys with subsequent homogenizin.o annealing at 400 deg C. The study has been made by the methods of differential thermal, microstructural analysis and by microhardness measurements. On the basis of literature data and data obtained a projection of the liquidus surface of the phase diagram for the system Ga-Bi-Te has been constructed. In the ternary system there are 17 curves of monovariant equilibrium dividing the liquidus into 10 fields of primary crystallization of phases, 9 points of non-variant equilibrium of which 4 points are triple eutectics and 5 points are triple peritectics

  15. Microstructural evolution of ternary Ag33Cu42Ge25 eutectic alloy inside ultrasonic field

    Directory of Open Access Journals (Sweden)

    Wei Zhai

    2014-12-01

    Full Text Available Ultrasonic field with a frequency of 20 kHz is introduced into the solidification process of ternary Ag33Cu42Ge25 eutectic alloy from the sample bottom to its top. The ultrasound stimulates the nucleation of alloy melt and prevents its bulk undercooling. At low ultrasound power of 250 W, the primary ε2 phase in the whole alloy sample grows into non-faceted equiaxed grains, which differs to its faceted morphology of long strip under static condition. The pseudobinary (Ag+ε2 eutectic transits from dendrite shape grain composed of rod type eutectic to equiaxed chrysanthemus shape formed by lamellar structure. By contrast, the ultrasound produces no obvious variation in the morphology of ternary (Ag+Ge+ε2 eutectic except a coarsening effect. When ultrasound power rises to 500 W, divorced ternary (Ag+Ge+ε2 eutectic forms at the sample bottom. However, in the upper part, the ultrasonic energy weakens, and it only brings about prominent refining effect to primary ε2 phase. The microstructural evolution mechanism is investigated on the cavitation, acoustic streaming and acoustic attenuation.

  16. Corrosion mechanism of T91 steel by Pb-Bi eutectic used as spallation target: importance for accelerator driven system; Mecanisme de corrosion de l'acier T91 par l'eutectique Pb-Bi utilise comme materiau de cible de spallation: importance pour les reacteurs hybrides

    Energy Technology Data Exchange (ETDEWEB)

    Martinelli, L

    2005-10-15

    The aim of this work has been to determine the oxidation mechanism of the martensitic steel T91 in the Pb-Bi liquid eutectic alloy, saturated in oxygen, at 470 C, in order to develop a long-term predictive model of the oxidation kinetics of the steel. This work enters in the framework of the lifetime studies of the spallation module demonstrator: MEGAPIE for the researches on hybrid reactors. An experimental characterization of the oxide layers has been carried out as well as the oxidation kinetics of the T91 steel. An oxidation mechanism has been elaborated from these experimental results and then simulated. The oxide layer formed at the T91 surface presents a duplex structure constituted by a magnetite external layer and a spinel Fe-Cr internal layer. A growth mechanism of the oxide layers has been proposed: the growth of the magnetite layer seems to be limited by the iron diffusion in the lattice of the duplex oxide layer. In parallel, an auto-regulation mechanism seems to govern the growth of the Fe-Cr spinel layer. This mechanism includes a non-limiting step of the oxygen diffusion in the oxide layer (by liquid way in the nano-channels of lead), as well as a limiting step of iron diffusion in the lattice of the oxide layer. In considering the proposed oxidation mechanisms, a simulation of the growth of the two oxide layers is carried out and compared to the long-time oxidation growth kinetics. The good agreement between the experimental results allows, finally, to strengthen the proposition of a long-term growth kinetic oxidation mechanism of the oxide layers. (O.M.)

  17. Lead-Bismuth technology ; corrosion resistance of structural materials

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Ji Young; Park, Won Seok [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2000-02-01

    Lead-Bismuth (Pb-Bi) eutectic alloy was determined as a coolant material for the HYPER system being studied by KAERI. The Pb-Bi alloy as a coolant, has a number of the favorable thermo-physical and technological properties, while it is comparatively corrosive to the structural materials. It is necessary to solve this problem for providing a long failure-proof operation of the facilities with Pb-Bi coolant. It seems to be possible to maintain corrosion resistance on structural material up to 600 deg C by using of various technologies, but it needs more studies for application to large-scale NPPs. 22 refs., 11 figs., 7 tabs. (Author)

  18. [sup 205]Bi/[sup 206]Bi cyclotron production from Pb-isotopes for absorption studies in humans

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, R.; Dresow, B.; Heinrich, H.C. (Universitaetskrankenhaus Eppendorf, Hamburg (Germany). Abt. Medizinische Biochemie); Wendel, J.; Bechtold, V. (Kernforschungszentrum Karlsruhe GmbH (Germany). Inst. fuer Kernphysik)

    1993-12-01

    Pb(p,xn) thick target excitation functions were measured in the energy range 10-38 MeV in order to optimize the production of isotopically pure radiobismuth from [sup nat]Pb, [sup 206]Pb, and [sup 207]Pb. Additionally, the decay of Po-isotopes from deuteron irradiation of natural bismuth ([sup 209]Bi) was exploited for radiobismuth production. [sup 205]Bi was produced from [sup 206]Pb at 20 MeV with only 2% of [sup 206]Bi at 4 weeks post irradiation. Bismuth compounds as used in the treatment of peptic ulcer were labeled with [sup 205]Bi for absorption studies in animals and subjects. (Author).

  19. Diffusivity, activity and solubility of oxygen in liquid lead and lead-bismuth eutectic alloy by electrochemical methods

    International Nuclear Information System (INIS)

    Ganesan, Rajesh; Gnanasekaran, T.; Srinivasa, Raman S.

    2006-01-01

    The diffusivity of oxygen in liquid lead and lead-bismuth eutectic (LBE) alloy was measured by a potentiostatic method and is given by log(D O Pb /cm 2 s -1 )=-2.554-2384/T(+/-0.070), 818-1061K, and log(D O LBE /cm 2 s -1 )=-0.813-3612/T(+/-0.091), 811-980K. The activity of oxygen in lead and LBE was determined by coulometric titration experiments. Using the measured data, the standard free energy of dissolution of oxygen in liquid lead and LBE was derived and is given byG O(Pb) xs =-121349+16.906T(+/-560)J(gatomO) -1 ,815-1090K,G O(LBE) xs = -127398+27.938T(+/-717)J(gatomO) -1 ,812-1012K.Using the above data, the Gibbs energy of formation of PbO(s) and equilibrium oxygen pressures measured over the oxygen-saturated LBE alloy, the solubility of oxygen in liquid lead and LBE were derived. The solubility of oxygen in liquid lead and LBE are given by log(S/at.%O)=-5100/T+4.32 (+/-0.04), 815-1090K and log(S/at.%O)=-4287/T+3.53 (+/-0.06), 812-1012K respectively.

  20. Structure of liquid Au-Si alloys around the eutectic region

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, S. [Faculty of Sciences, Kyushu University, Ropponmatsu Fukuoka 810-8560 (Japan)], E-Mail: takeda@rc.kyushu-u.ac.jp; Fujii, H. [Graduate School of Sciences, Kyushu University, Ropponmatsu Fukuoka 810-8560 (Japan); Kawakita, Y. [Faculty of Sciences, Kyushu University, Ropponmatsu Fukuoka 810-8560 (Japan); Kato, Y. [Graduate School of Sciences, Kyushu University, Ropponmatsu Fukuoka 810-8560 (Japan); Fujita, S. [Graduate School of Sciences, Kyushu University, Ropponmatsu Fukuoka 810-8560 (Japan); Yokota, Y. [Graduate School of Sciences, Kyushu University, Ropponmatsu Fukuoka 810-8560 (Japan); Kohara, S. [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouo Mikazuki-cho, Sayou-gun Hyogo 670-5198 (Japan)

    2007-03-25

    X-ray diffraction measurements have been carried out for liquid Au-Si alloys around the eutectic region by the transmission method using high-energy X-ray to investigate the atomic arrangements in the liquid state. From the temperature dependence of the observed structure factors, the partial pair correlation and the detailed atomic arrangements will be discussed on the basis of a Reverse Monte Carlo analysis. The reproduced atomic arrangements around the eutectic region suggest the substitution structure and also rather dense liquid with decreasing temperature.

  1. On the performance of a novel grain refiner in hyper-eutectic Al-Si cast alloys

    OpenAIRE

    Bolzoni, L; Nowak, M; Hari Babu, N

    2014-01-01

    The stringent requirements for pollution reduction are pushing the automotive industry towards the employment of lightweight structures and, therefore, aluminium and its alloys play a remarkable role. Al-Si casting alloy with eutectic or hyper- eutectic compositions are, normally, employed for the production of high performance automotive products such as pistons and engine blocks which have to withstand critical loading conditions (i.e. high temperature, high pressure and corrosive exhaust g...

  2. Chip bonding of low-melting eutectic alloys by transmitted laser radiation

    Science.gov (United States)

    Hoff, Christian; Venkatesh, Arjun; Schneider, Friedrich; Hermsdorf, Jörg; Bengsch, Sebastian; Wurz, Marc C.; Kaierle, Stefan; Overmeyer, Ludger

    2017-06-01

    Present-day thermode bond systems for the assembly of radio-frequency identification (RFID) chips are mechanically inflexible, difficult to control, and will not meet future manufacturing challenges sufficiently. Chip bonding, one of the key processes in the production of integrated circuits (ICs), has a high potential for optimization with respect to process duration and process flexibility. For this purpose, the technologies used, so far, are supposed to be replaced by a transmission laser-bonding process using low-melting eutectic alloys. In this study, successful bonding investigations of mock silicon chips and of RFID chips on flexible polymer substrates are presented using the low-melting eutectic alloy, 52In48Sn, and a laser with a wavelength of 2 μm.

  3. Creep of Two-Phase Microstructures for Microelectronic Applications

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, Heidi Linch [Univ. of California, Berkeley, CA (United States)

    1998-12-01

    The mechanical properties of low-melting temperature alloys are highly influenced by their creep behavior. This study investigates the dominant mechanisms that control creep behavior of two-phase, low-melting temperature alloys as a function of microstructure. The alloy systems selected for study were In-Ag and Sn-Bi because their eutectic compositions represent distinctly different microstructure.” The In-Ag eutectic contains a discontinuous phase while the Sn-Bi eutectic consists of two continuous phases. In addition, this work generates useful engineering data on Pb-free alloys with a joint specimen geometry that simulates microstructure found in microelectronic applications. The use of joint test specimens allows for observations regarding the practical attainability of superplastic microstructure in real solder joints by varying the cooling rate. Steady-state creep properties of In-Ag eutectic, Sn-Bi eutectic, Sn-xBi solid-solution and pure Bi joints have been measured using constant load tests at temperatures ranging from O°C to 90°C. Constitutive equations are derived to describe the steady-state creep behavior for In-Ageutectic solder joints and Sn-xBi solid-solution joints. The data are well represented by an equation of the form proposed by Dom: a power-law equation applies to each independent creep mechanism. Rate-controlling creep mechanisms, as a function of applied shear stress, test temperature, and joint microstructure, are discussed. Literature data on the steady-state creep properties of Sn-Bi eutectic are reviewed and compared with the Sn-xBi solid-solution and pure Bi joint data measured in the current study. The role of constituent phases in controlling eutectic creep behavior is discussed for both alloy systems. In general, for continuous, two-phase microstructure, where each phase exhibits significantly different creep behavior, the harder or more creep resistant phase will dominate the creep behavior in a lamellar microstructure. If a

  4. The Effect of Wetting Gravity Regime on Shear Strength of SAC and Sn-Pb Solder Lap Joints

    Science.gov (United States)

    Sona, Mrunali; Prabhu, K. Narayan

    2017-09-01

    The failure of solder joints due to imposed stresses in an electronic assembly is governed by shear bond strength. In the present study, the effect of wetting gravity regime on single-lap shear strength of Sn-0.3Ag-0.7Cu and Sn-2.5Ag-0.5Cu solder alloys reflowed between bare copper substrates as well as Ni-coated Cu substrates was investigated. Samples were reflowed for 10 s, T gz (time corresponding to the end of gravity regime) and 100 s individually and tested for single-lap shear strength. The single-lap shear test was also carried out on eutectic Sn-Pb/Cu- and Sn-Pb/Ni-coated Cu specimens to compare the shear strength values obtained with those of lead-free alloys. The eutectic Sn-Pb showed significantly higher ultimate shear strength on bare Cu substrates when compared to Sn-Ag-Cu alloys. However, SAC alloys reflowed on nickel-coated copper substrate exhibited higher shear strength when compared to eutectic Sn-Pb/Ni-coated Cu specimens. All the substrate/solder/substrate lap joint specimens that were reflowed for the time corresponding to the end of gravity regime exhibited maximum ultimate shear strength.

  5. Directional solidification of Zn-Al-Cu eutectic alloy by the vertical Bridgman method

    Directory of Open Access Journals (Sweden)

    Büyük U.

    2015-01-01

    Full Text Available In the present work, the effect of growth rate and temperature gradient on microstructure and mechanical properties of Zn-7wt.%Al-4wt.%Cu eutectic alloy has been investigated. Alloys prepared under steady-state conditions by vacuumed hot filing furnace. Then, the alloys were directionally solidified upward with different growth rates (V=11.62-230.77 mm/s at a constant temperature gradient (G=7.17 K/mm and with different temperature gradients (G=7.17-11.04 K/mm at a constant growth rate (V=11.62 mm/s by a Bridgman furnace. The microstructures were observed to be lamellae of Zn, Al and broken lamellae CuZn4 phases from quenched samples. The values of eutectic spacing, microhardness and ultimate tensile strength of alloys were measured. The dependency of the microstructure and mechanical properties on growth rate and temperature gradient were investigated using regression analysis.

  6. Validated thermodynamic prediction of AlP and eutectic (Si) solidification sequence in Al-Si cast alloys

    International Nuclear Information System (INIS)

    Liang, S M; Schmid-Fetzer, R

    2016-01-01

    The eutectic microstructure in hypoeutectic Al-Si cast alloys is strongly influenced by AlP particles which are potent nuclei for the eutectic (Si) phase. The solidification sequence of AlP and (Si) phases is, thus, crucial for the nucleation of eutectic silicon with marked impact on its morphology. This study presents this interdependence between Si- and P-compositions, relevant for Al-Si cast alloys, on the solidification sequence of AlP and (Si). These data are predicted from a series of thermodynamic calculations. The predictions are based on a self-consistent thermodynamic description of the Al-Si-P ternary alloy system developed recently. They are validated by independent experimental studies on microstructure and undercooling in hypoeutectic Al-Si alloys. A constrained Scheil solidification simulation technique is applied to predict the undercooling under clean heterogeneous nucleation conditions, validated by dedicated experimental observations on entrained droplets. These specific undercooling values may be very large and their quantitative dependence on Si and P content of the Al alloy is presented. (paper)

  7. Obtención de aleaciones eutécticas PbLi mediante procesos de fusión

    Directory of Open Access Journals (Sweden)

    Barrena, M. I.

    2012-12-01

    Full Text Available The development of thermonuclear experimental reactor (ITER, whose objective is to produce energy from nuclear fusion, has raised the study of Pb-Li eutectic alloys, as they have been selected for the manufacture of test blanket modules (TBM. However, during the manufacturing process of the Pb-Li alloys, thermal conditions used result in a loss of litium element, which inhibits the formation of eutectic structures. In this work we have done fusion of pure lead and lithium, evaluating different process parameters to obtain Pb-Li (17 at. % eutectic alloys. The alloys manufactured were characterized by DSC, SEM-EDX and microhardness tests. From these studies we noted that the used of an induction reactor and the process parameters optimized to obtain Pb-Li alloy allow for completely eutectic ingots and high chemical homogeneity and microstructural.

    El desarrollo del reactor experimental termonuclear (ITER, cuyo objetivo es la producción de energía a partir de la fusión nuclear, ha suscitado el estudio de las aleaciones eutécticas Pb-Li, ya que éstas han sido seleccionadas para la fabricación de las envolturas regeneradoras del reactor (TBM. Sin embargo, durante el proceso de fabricación de las aleaciones Pb-Li se produce una pérdida de litio, que inhibe la formación de estructuras eutécticas. En el presente trabajo se han realizado fusiones partiendo de plomo y litio puros evaluando diferentes parámetros de proceso para la obtención de aleaciones eutécticas Pb-Li (17 % at.. Las aleaciones obtenidas fueron caracterizadas mediante calorimetría diferencial de barrido, microscopía SEM-EDX y microdureza. De estos estudios podemos señalar, que la utilización de hornos de inducción y los parámetros de proceso optimizados para la obtención de la aleación Pb-Li, permiten obtener lingotes completamente eutécticos y con gran homogeneidad química y microestructural.

  8. Microstructure of directionally solidified Ti-Fe eutectic alloy with low interstitial and high mechanical strength

    Science.gov (United States)

    Contieri, R. J.; Lopes, E. S. N.; Taquire de La Cruz, M.; Costa, A. M.; Afonso, C. R. M.; Caram, R.

    2011-10-01

    The performance of Ti alloys can be considerably enhanced by combining Ti and other elements, causing an eutectic transformation and thereby producing composites in situ from the liquid phase. This paper reports on the processing and characterization of a directionally solidified Ti-Fe eutectic alloy. Directional solidification at different growth rates was carried out in a setup that employs a water-cooled copper crucible combined with a voltaic electric arc moving through the sample. The results obtained show that a regular fiber-like eutectic structure was produced and the interphase spacing was found to be a function of the growth rate. Mechanical properties were measured using compression, microindentation and nanoindentation tests to determine the Vickers hardness, compressive strength and elastic modulus. Directionally solidified eutectic samples presented high values of compressive strength in the range of 1844-3000 MPa and ductility between 21.6 and 25.2%.

  9. Thermoelectric and morphological effects of Peltier pulsing on directional solidification of eutectic Bi-Mn

    Science.gov (United States)

    Silberstein, R. P.; Larson, D. J., Jr.; Dressler, B.

    1984-01-01

    Extensive in situ thermal measurements using Peltier Interface Demarcation (PID) during directional solidification of eutectic Bi/MnBi were carried out. Observations indicate that significant thermal transients occur throughout the sample as a result of the Peltier pulsing. The contributions of the Peltier, Thomson, and Joule heats were separated and studied as a function of pulse intensity and polarity. The Joule and the combined Peltier and Thomson thermal contributions were determined as a function of time during and after the current pulses, close to the solid/liquid interface. Variations of the Bi/MnBi particle morphology clearly reveal the interface shape, changes in interface velocity, meltback, and temporary loss of cooperative growth, as a result of the pulsing.

  10. Oxidation of Pb-Sn and Pb-Sn-In alloys

    International Nuclear Information System (INIS)

    Sluzewski, D.A.; Chang, Y.A.; Marcotte, V.C.

    1990-01-01

    Air oxidized Pb-Sn and Pb-Sn-In single phase alloys have been studied with scanning Auger microscopy. Line scans across grain boundaries combined with argon ion sputter etching revealed grain boundary oxidation. In the Pb-Sn samples, tin is preferentially oxidized with the grain boundary regions having a much higher percentage of tin oxide than the bulk surface oxide. In the Pb-Sn-In alloys, both tin and indium are preferentially oxidized with the grain boundary regions being enriched with tin and indium oxides

  11. Theoretical basis of oxygen pressure control in liquid Pb-Bi using YSZ

    International Nuclear Information System (INIS)

    Jung, S. H.; Hwang, I. S.; Park, B. K.

    2002-01-01

    To develop a liquid Pb-Bi cooled reactor, it is necessary to solve the structural material corrosion problem caused by Pb-Bi. This experiment examine the fundamental behaviors to practically test the oxide film formation on the surface of structural material known as solution of corrosion inhibition in liquid Pb-Bi. The corrosion inhibition through oxide film formation is to prevent metals from dissolving into liquid Pb-Bi though not forming coolants slug resulted from oxidation. In this paper, we examined the oxygen pressure controllability using YSZ in cover gas, and theoretically derived the relationship between oxygen cover gas pressure and dissolved oxygen in liquid Pb-Bi

  12. Metallurgical Parameters Controlling the Eutectic Silicon Charateristics in Be-Treated Al-Si-Mg Alloys.

    Science.gov (United States)

    Ibrahim, Mohamed F; Elgallad, Emad M; Valtierra, Salvador; Doty, Herbert W; Samuel, Fawzy H

    2016-01-27

    The present work was carried out on Al-7%Si-0.4%Mg-X alloy (where X = Mg, Fe, Sr or Be), where the effect of solidification rate on the eutectic silicon characteristics was investigated. Two solidification rates corresponding to dendrite arm spacings (DAS) of 24 and 65 μm were employed. Samples with 24 μm DAS were solution heat-treated at 540 °C for 5 and 12 h prior to quenching in warm water at 65 °C. Eutectic Si particle charateristics were measured using an image analyzer. The results show that the addition of 0.05% Be leads to partial modification of the Si particles. Full modification was only obtained when Sr was added in an amount of 150-200 ppm, depending on the applied solidification rate. Increasing the amount of Mg to 0.8% in Sr-modified alloys leads to a reduction in the effectiveness of Sr as the main modifier. Similar observations were made when the Fe content was increased in Be-treated alloys due to the Be-Fe interaction. Over-modification results in the precipitation of hard Sr-rich particles, mainly Al₄SrSi₂, whereas overheating causes incipient melting of the Al-Cu eutectic and hence the surrounding matrix. Both factors lead to a deterioration in the alloy mechanical properties. Furthermore, the presence of long, acicular Si particles accelerates the occurrence of fracture and, as a result, yields poor ductility. In low iron (less than 0.1 wt%) Al-Si-Mg alloys, the mechanical properties in the as cast, as well as heat treated conditions, are mainly controlled by the eutectic Si charatersitics. Increasing the iron content and, hence, the volume fraction of Fe-based intermetallics leads to a complex fracture mode.

  13. Metallurgical Parameters Controlling the Eutectic Silicon Charateristics in Be-Treated Al-Si-Mg Alloys

    Directory of Open Access Journals (Sweden)

    Mohamed F. Ibrahim

    2016-01-01

    Full Text Available The present work was carried out on Al-7%Si-0.4%Mg-X alloy (where X = Mg, Fe, Sr or Be, where the effect of solidification rate on the eutectic silicon characteristics was investigated. Two solidification rates corresponding to dendrite arm spacings (DAS of 24 and 65 μm were employed. Samples with 24 μm DAS were solution heat-treated at 540 °C for 5 and 12 h prior to quenching in warm water at 65 °C. Eutectic Si particle charateristics were measured using an image analyzer. The results show that the addition of 0.05% Be leads to partial modification of the Si particles. Full modification was only obtained when Sr was added in an amount of 150–200 ppm, depending on the applied solidification rate. Increasing the amount of Mg to 0.8% in Sr-modified alloys leads to a reduction in the effectiveness of Sr as the main modifier. Similar observations were made when the Fe content was increased in Be-treated alloys due to the Be-Fe interaction. Over-modification results in the precipitation of hard Sr-rich particles, mainly Al4SrSi2, whereas overheating causes incipient melting of the Al-Cu eutectic and hence the surrounding matrix. Both factors lead to a deterioration in the alloy mechanical properties. Furthermore, the presence of long, acicular Si particles accelerates the occurrence of fracture and, as a result, yields poor ductility. In low iron (less than 0.1 wt% Al-Si-Mg alloys, the mechanical properties in the as cast, as well as heat treated conditions, are mainly controlled by the eutectic Si charatersitics. Increasing the iron content and, hence, the volume fraction of Fe-based intermetallics leads to a complex fracture mode.

  14. Pb-for-Bi substitution for enhancing thermoelectric characteristics of [(Bi,Pb)2Ba2O4+/-ω]0.5CoO2

    Science.gov (United States)

    Sakai, K.; Karppinen, M.; Chen, J. M.; Liu, R. S.; Sugihara, S.; Yamauchi, H.

    2006-06-01

    We report strongly enhanced thermoelectric characteristics for a misfit-layered oxide, [Bi2Ba2O4±ω]0.5CoO2, in a wide temperature range, as achieved through substituting up to 20% of Bi by Pb. The Pb substitution kept the thermal conductivity (κ) unchanged but decreased the electrical resistivity (ρ) and increased the Seebeck coefficient (S) simultaneously, such that a three-fold enhancement in the thermoelectric figure of merit, Z (≡S2/ρκ), was realized. At the same time x-ray absorption near-edge structure data indicated that the valence and spin states of Co are not affected by the Pb-for-Bi substitution.

  15. Solidified structure of Al-Pb-Cu alloys

    International Nuclear Information System (INIS)

    Ikeda, Tetsuyuki; Nishi, Seiki; Kumeuchi, Hiroyuki; Tatsuta, Yoshinori.

    1986-01-01

    Al-Pb-Cu alloys were cast into bars or plates in different two metal mold casting processes in order to suppress gravity segregation of Pb and to achieve homogeneous dispersion of Pb phase in the alloys. Solidified structures were analyzed by a video-pattern-analyzer. Plate castings 15 to 20 mm in thickness of Al-Pb-1 % Cu alloy containing Pb up to 5 % in which Pb phase particles up to 10 μm disperse are achieved through water cooled metal mold casting. The plates up to 5 mm in thickness containing Pb as much as 8 to 10 % cast in this process have dispersed Pb particles up to 5 μm in diameter in the surface layer. Al-8 % Pb-1 % Cu alloy bars 40 mm in diameter and 180 mm in height in which gravity segregation of Pb is prevented can be cast by movable and water sprayed metal mold casting at casting temperature 920 deg C and mold moving speed 1.0 mm/s. Pb phase particles 10 μm in mean size are dispersed in the bars. (author)

  16. Effects of Eutectic Si and Secondary Dendrite Arm Spacing on the Mechanical Properties of Al-Si-Cu Cast Alloys

    International Nuclear Information System (INIS)

    Lee, Kyungmin; Kim, Yumi; Kim, Youngman; Hong, Sungkil; Choi, Seweon; Kim, Youngchan; Kang, Changseok

    2014-01-01

    The present study aims at investigating the effects of eutectic Si and Secondary dendrite arm spacing (SDAS) on mechanical properties of Al-Si-Cu alloy. Heat treatment and controlling of solidification rate affect to microstructure of Al-Si-Cu alloy. Al-Si-Cu alloy was dissolved in an electric furnace. The alloy cast in STD61 mold which had been pre-heated to 95 ℃ and 200 ℃. Eutectic Si and SDAS were finer as cooling rate increased. Image analysis technique has been utilized to examine the microstructure. Microstructure observation results showed that T6 heat treatment has a strong influence eutectic Si particle morphology. The mechanical properties, such as tensile strength, yield strength, elongation, were improved by ASTM E8 standard. Tensile properties of the Al-Si-Cu alloys prepared by different cooling rates were the same as each other by T6 heat treatment.

  17. Pressure-induced structural change in liquid GaIn eutectic alloy

    DEFF Research Database (Denmark)

    Yu, Q.; Ahmad, A. S.; Ståhl, Kenny

    2017-01-01

    Synchrotron x-ray diffraction reveals a pressure induced crystallization at about 3.4 GPa and a polymorphic transition near 10.3 GPa when compressed a liquid GaIn eutectic alloy up to ~13 GPa at room temperature in a diamond anvil cell. Upon decompression, the high pressure crystalline phase...

  18. On the existence of PbBi3PO8

    International Nuclear Information System (INIS)

    Steinfink, H.; Dass, R.I.; Lynch, V.; Harlow, R.L.; Lee, P.L.

    2005-01-01

    The title compound crystallizes in the tetragonal system, a = 11.733(2) A, c = 15.587(3) A, I4 mm, Z = 10. Data were collected at the Argonne National Laboratory synchrotron source at λ = 0.15359 A. Least squares refinement on F 2 converged to R1 = 0.039. The oxygen coordination polyhedra around Bi and Pb display the distortions typical of 6s 2 lone-pair atoms. One Bi is disordered. Bi-O bonds vary from 2.08(2) to 2.96(1) A. One Pb is in cubic coordination to oxygen and the second Pb is bonded to six oxygen atoms that form a rectangular pyramid and a seventh oxygen is off one of the rectangular faces of the pyramid. Pb-O bonds vary from 2.303(6) to 2.804(17) A. Of the two crystallographically independent P one is in a single tetrahedral coordination while the second is at the center of two disordered tetrahedra. Units of OM 4 tetrahedra, M = Bi/Pb, articulate into a three-dimensional framework by corner and edge sharing that is strengthened by corner sharing with PO 4 moieties

  19. Pressure induced phase transition in Pb6Bi2S9

    DEFF Research Database (Denmark)

    Olsen, Lars Arnskov; Friese, Karen; Makovicky, Emil

    2011-01-01

    consists of two types of moduli with SnS/TlI archetype structure in which the Pb and Bi lone pairs are strongly expressed. The mechanism of the phase transition is described in detail and the results are compared to the closely related phase transition in Pb3Bi2S6 (lillianite).......The crystal structure of Pb6Bi2S9 is investigated at pressures between 0 and 5.6 GPa with X-ray diffraction on single-crystals. The pressure is applied using diamond anvil cells. Heyrovskyite (Bbmm, a = 13.719(4) Å, b = 31.393(9) Å, c = 4.1319(10) Å, Z = 4) is the stable phase of Pb6Bi2S9...... at ambient conditions and is built from distorted moduli of PbS-archetype structure with a low stereochemical activity of the Pb2+ and Bi3+ lone electron pairs. Heyrovskyite is stable until at least 3.9 GPa and a first-order phase transition occurs between 3.9 and 4.8 GPa. A single-crystal is retained after...

  20. Conceptual design tool development for a Pb-Bi cooled reactor

    International Nuclear Information System (INIS)

    Lee, K. G.; Chang, S. H.; No, H. C.; Chunm, M. H.

    2000-01-01

    Conceptual design is generally ill-structured and mysterious problem solving. This leads the experienced experts to be still responsible for the most of synthesis and analysis task, which are not amenable to logical formulations in design problems. Especially because a novel reactor such as a Pb-Bi cooled reactor is going on a conceptual design stage, it will be very meaningful to develop the conceptual design tool. This tool consists of system design module with artificial intelligence, scaling module, and validation module. System design decides the optimal structure and the layout of a Pb-Bi cooled reactor, using design synthesis part and design analysis part. The designed system is scaled to be optimal with desired power level, and then the design basis accidents (Dbase) are analyzed in validation module. Design synthesis part contains the specific data for reactor components and the general data for a Pb-Bi cooled reactor. Design analysis part contains several design constraints for formulation and solution of a design problem. In addition, designer's intention may be externalized through emphasis on design requirements. For the purpose of demonstration, the conceptual design tool is applied to a Pb-Bi cooled reactor with 125 M Wth of power level. The Pb-Bi cooled reactor is a novel reactor concept in which the fission-generated heat is transferred from the primary coolant to the secondary coolant through a reactor vessel wall of a novel design. The Pb-Bi cooled reactor is to deliver 125 M Wth per module for 15 effective full power years without any on-site fuel handling. The conceptual design tool investigated the feasibility of a Pb-Bi cooled reactor. Application of the conceptual design tool will be, in detail, presented in the full paper. (author)

  1. Effect of silver and indium addition on mechanical properties and indentation creep behavior of rapidly solidified Bi–Sn based lead-free solder alloys

    International Nuclear Information System (INIS)

    Shalaby, Rizk Mostafa

    2013-01-01

    Mechanical properties and indentation creep of the melt-spun process Bi–42 wt%Sn, Bi–40 wt%Sn–2 wt%In, Bi–40 wt%Sn–2 wt%Ag and Bi–38 wt%Sn–2 wt%In–2 wt%Ag were studied by dynamic resonance technique and Vickers indentation testing at room temperature and compared to that of the traditional Sn–37 wt%Pb eutectic alloy. The results show that the structure of Bi–42 wt%Sn alloy is characterized by the presence of rhombohedral Bi and body centered tetragonal β-Sn. The two ternary alloys exhibit additional constituent phases of intermetallic compounds SnIn 19 for Bi–40 wt%Sn–2 wt%In and ε-Ag 3 Sn for Bi–40 wt%Sn–2 wt%Ag alloys. Attention has been paid to the role of intermetallic compounds on mechanical and creep behavior. The In and Ag containing solder alloy exhibited a good combination of higher creep resistance, good mechanical properties and lower melting temperature as compared with Pb–Sn eutectic solder alloy. This was attributed to the strengthening effect of Bi as a strong solid solution element in the Sn matrix and formation of intermetallic compounds β-SnBi, ε-Ag 3 Sn and InSn 19 which act as both strengthening agent and grain refiner in the matrix of the material. Addition of In and Ag decreased the melting temperature of Bi–Sn lead-free solder from 143 °C to 133 °C which was possible mainly due to the existence of InSn 19 and Ag 3 Sn intermetallic compounds. Elastic constants, internal friction and thermal properties of Bi–Sn based alloys have been studied and analyzed.

  2. Effect of Bi on the corrosion resistance of zirconium alloys

    International Nuclear Information System (INIS)

    Yao Meiyi; Zhou Bangxin; Li Qiang; Zhang Weipeng; Zhu Li; Zou Linghong; Zhang Jinlong; Peng Jianchao

    2014-01-01

    In order to investigate systematically the effect of Bi addition on the corrosion resistance of zirconium alloys, different zirconium-based alloys, including Zr-4 (Zr-l.5Sn-0.2Fe-0.1Cr), S5 (Zr-0.8Sn-0.35Nb-0.4Fe-0.1Cr), T5 (Zr-0.7Sn-l.0Nb-0.3Fe-0.1Cr) and Zr-1Nb, were adopted to prepare the zirconium alloys containing Bi of 0∼0.5% in mass fraction. These alloys were denoted as Zr-4 + xBi, S5 + xBi, T5 + xBi and Zr-1Nb + xBi, respectively. The corrosion behavior of these specimens was investigated by autoclave testing in lithiated water with 0.01 M LiOH or deionized water at 360 ℃/18.6 MPa and in superheated steam at 400 ℃/10.3 MPa. The microstructure of the alloys was examined by TEM and the second phase particles (SPPs) were analyzed by EDS. Microstructure observation shows that the addition of Bi promotes the precipitation of Sn as second phase particles (SPPs) because Sn is in solid solution in α-Zr matrix in Zr-4, S5 and T5 alloys. The concentration of Bi dissolved in α-Zr matrix increase with the increase of Nb in the alloys, and the excess Bi precipitates as Bi-containing SPPs. The corrosion results show that the effect of Bi addition on the corrosion behavior of different zirconium-based alloys is very complicated, depending on their compositions and corrosion conditions. In the case of higher Bi concentration in α-Zr, the zirconium alloys exhibit better corrosion resistance. However, in the case of precipitation of Bi-containing SPPs, the corrosion resistance gets worse. This indicates that the solid solution of Bi in α-Zr matrix can improve the corrosion resistance, while the precipitation of the Bi-containing SPPs is harmful to the corrosion resistance. (authors)

  3. Growth and solid/solid transformation in a Ni-Si eutectic alloy

    Energy Technology Data Exchange (ETDEWEB)

    Dutra, A.T. [Department of Materials Engineering, State University of Campinas, P.O. Box 6122, Campinas 13083-970, SP (Brazil); Ferrandini, P.L. [Department of Materials Engineering, State University of Campinas, P.O. Box 6122, Campinas 13083-970, SP (Brazil); Costa, C.A.R. [Institute of Chemistry, State University of Campinas, P.O. Box 6154, Campinas 13083-970, SP (Brazil); Goncalves, M.C. [Institute of Chemistry, State University of Campinas, P.O. Box 6154, Campinas 13083-970, SP (Brazil); Caram, R. [Department of Materials Engineering, State University of Campinas, P.O. Box 6122, Campinas 13083-970, SP (Brazil)]. E-mail: rcaram@fem.unicamp.br

    2005-08-16

    High temperature structural components demand materials that maintain satisfactory mechanical and chemical characteristics. These needs may be met by applying some eutectic alloys, including Ni-Ni{sub 3}Si. This paper deals with the directional solidification of Ni-Ni{sub 3}Si grown under several growth rates. The analysis of the eutectic microstructure was carried out using atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). The results obtained provided a precise analysis of the Ni{sub 3}Si phase. It could be noticed that the solid/solid transformations by which Ni{sub 3}Si phase goes through, deeply affects its morphology. In addition, quantitative information on the eutectic structure was obtained. It was confirmed that the growth rate variation deeply affects the final microstructure as it influences the efficiency of atomic diffusion along the solid/liquid interface.

  4. Growth and solid/solid transformation in a Ni-Si eutectic alloy

    International Nuclear Information System (INIS)

    Dutra, A.T.; Ferrandini, P.L.; Costa, C.A.R.; Goncalves, M.C.; Caram, R.

    2005-01-01

    High temperature structural components demand materials that maintain satisfactory mechanical and chemical characteristics. These needs may be met by applying some eutectic alloys, including Ni-Ni 3 Si. This paper deals with the directional solidification of Ni-Ni 3 Si grown under several growth rates. The analysis of the eutectic microstructure was carried out using atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). The results obtained provided a precise analysis of the Ni 3 Si phase. It could be noticed that the solid/solid transformations by which Ni 3 Si phase goes through, deeply affects its morphology. In addition, quantitative information on the eutectic structure was obtained. It was confirmed that the growth rate variation deeply affects the final microstructure as it influences the efficiency of atomic diffusion along the solid/liquid interface

  5. Determining metal ion distributions using resonant scattering at very high-energy K-edges: Bi/Pb in Pb5Bi6Se14

    International Nuclear Information System (INIS)

    Zhang Yuegang; Lee, P.L.; Shastri, S.D.; Shu Deming; Wilkinson, A.P.; Chung Duck-Young; Kanatzidis, M.G.

    2005-01-01

    Powder diffraction data collected at ∝ 86 keV, and just below both the Pb and the Bi K-edges, on an imaging plate detector using synchrotron radiation from the Advanced Photon Source have been used to examine the Pb/Bi distribution over the 11 crystallographically distinct sites in Pb 5 Bi 6 Se 14 [space group P2 1 /m, a=16.0096(2) Aa, b=4.20148(4) Aa, c=21.5689(3) Aa and β=97.537(1) 0 ]. The scattering factors needed for the analyses were determined both by Kramers- Kronig transformation of absorption spectra and by analyses of diffraction patterns from reference compounds. Even with the relatively low scattering contrast that is available at the K-edges, it was possible to determine the Pb/Bi distribution and probe the presence of cation site vacancies in the material. The current results indicate that resonant scattering measurements at high-energy K-edges are a viable, and perhaps preferable, route to site occupancies when absorption from the sample or sample environment/container is a major barrier to the acquisition of high-quality resonant scattering data at lower-energy edges

  6. Aging effects on fracture behavior of 63Sn37Pb eutectic solder during tensile tests under the SEM

    International Nuclear Information System (INIS)

    Ding Ying; Wang Chunqing; Li Mingyu; Bang Hansur

    2004-01-01

    This study investigates the influence of aging treatment on fracture behavior of Sn-Pb eutectic solder alloys at different loading rate regime during tensile tests under the scanning electron microscope. In high homologous temperature, the solder exhibit the creep behavior that could be confirmed through the phenomena of grain boundary sliding (GBS) to both as-cast and aged specimens. Owing to the large grain scale after high temperature storage, boundary behavior was limited to some extent for the difficulty in grain rotation and boundary migration. Instead, drastic intragranular deformation occurred. Also, the phase coarsening weakened the combination between lead-rich phase and tin matrix. Consequently, surface fragmentation was detected for the aged specimens. Furthermore, the fracture mechanism changed from intergranular dominated to transgranular dominated with increasing loading rate to both specimens during early stage

  7. Filtration of aluminum alloys and its influence on mechanical properties and shape of eutectical silicium

    Directory of Open Access Journals (Sweden)

    M. Brůna

    2008-07-01

    Full Text Available Filtration during casting of high quality aluminum alloys belongs to main refining methods. Even when there are many years of experiences and experimental works on this subject, there are still some specific anomalies. While using ceramic filtration media during casting of aluminum alloys, almost in all experiments occurred increase of strength limit and atypical increase of extension. This anomaly was not explained with classical metallurgical methods, black-white contrast after surface etching neither with color surface etching. For that reason was used deep etching on REM. By using pressed ceramic filters, by studying morphology eutectical silicon was observed modification morphology of eutectical silicon, this explains increase extension after filtration. Pressed ceramic filters were used on experimental works. Casting was executed on hardenable alloy AlSi10MgMn.

  8. On the stable eutectic solidification of iron–carbon–silicon alloys

    International Nuclear Information System (INIS)

    Stefanescu, Doru M.; Alonso, Gorka; Larrañaga, Pello; Suarez, Ramon

    2016-01-01

    Extensive effort was expanded to elucidate the growth and morphology of the stable eutectic grains during early solidification of continuous cooled Fe–C–Si alloys. To this purpose, quenching experiments at successive stages during solidification have been carried out on five cast irons with various magnesium and titanium levels designed to produce graphite morphologies ranging from lamellar to mixed compacted–spheroidal. The graphite shape factors were measured on the metallographic samples, and their evolution as a function of the chemical composition and the solid fraction was analyzed. Extensive scanning electron microscopy was carried on to evaluate the change in graphite shape during early solidification, to establish the fraction of solid at which the transition from spheroidal-to-compacted-to-lamellar graphite occurs, and to outline the early morphology of the eutectic grains. It was confirmed that solidification of Mg containing irons started with the development of spheroidal graphite even at Mg levels as low as 0.013 mass%. Then, as solidification proceeds, when some spheroids developed one or more tails (tadpole graphite), the spheroidal-to-compacted graphite transition occurs. The new findings were then integrated in previous knowledge to produce an understanding of the eutectic solidification of these materials. It was concluded that in hypoeutectic lamellar graphite iron austenite/graphite eutectic grains can nucleate at the austenite/liquid interface or in the bulk of the liquid, depending on the sulfur content and on the cooling rate. When graphite nucleation occurs on the primary austenite, several eutectic grains can nucleate and grow on the same dendrite. The primary austenite continues growing as eutectic austenite and therefore the two have the same crystallographic orientation. Thus, a final austenite grain may include several eutectic grains. In eutectic irons the eutectic grains nucleate and grow mostly in the liquid. The eutectic

  9. Eutectic reaction analysis between TRU-50%Zr alloy fuel and HT-9 cladding, and temperature prediction of eutectic reaction under steady-state

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Woan; Lee, Byoung Oon; Lee, Bong Sang; Park, Won Seok

    2001-02-01

    Blanket fuel assembly for HYPER contains a bundle of pins arrayed in triangular pitch, which has hexagonal bundle structure. The reference blanket fuel pin consists of the fuel slug of TRU-50wt%Zr alloy and the cladding material of ferritic martensite steel, HT-9. Chemical interaction between fuel slug and cladding is one of the major concerns in metallic fuel rod design. The contact of metallic fuel slug and stainless steel cladding in a fuel rod forms a complex multi-component diffusion couple at elevated temperatures. The potential problem of inter-diffusion of fuel and cladding components is essentially two-fold weakening of cladding mechanical strength due to the formation of diffusion zones in the cladding, and the formation of comparatively low melting point phases in the fuel/cladding interface to develop eutectic reaction. The main components of fuel slug are composed of zirconium alloying element in plutonium matrix, including neptunium, americium and uranium additionally. Therefore basic eutectic reaction change of Pu-Fe binary system can be assessed, while it is estimated how much other elements zirconium, uranium, americium and neptunium influence on plutonium phase stability. Afterwards it is needed that eutectic reaction is verified through experimental necessarily.

  10. Eutectic reaction analysis between TRU-50%Zr alloy fuel and HT-9 cladding, and temperature prediction of eutectic reaction under steady-state

    International Nuclear Information System (INIS)

    Hwang, Woan; Lee, Byoung Oon; Lee, Bong Sang; Park, Won Seok

    2001-02-01

    Blanket fuel assembly for HYPER contains a bundle of pins arrayed in triangular pitch, which has hexagonal bundle structure. The reference blanket fuel pin consists of the fuel slug of TRU-50wt%Zr alloy and the cladding material of ferritic martensite steel, HT-9. Chemical interaction between fuel slug and cladding is one of the major concerns in metallic fuel rod design. The contact of metallic fuel slug and stainless steel cladding in a fuel rod forms a complex multi-component diffusion couple at elevated temperatures. The potential problem of inter-diffusion of fuel and cladding components is essentially two-fold weakening of cladding mechanical strength due to the formation of diffusion zones in the cladding, and the formation of comparatively low melting point phases in the fuel/cladding interface to develop eutectic reaction. The main components of fuel slug are composed of zirconium alloying element in plutonium matrix, including neptunium, americium and uranium additionally. Therefore basic eutectic reaction change of Pu-Fe binary system can be assessed, while it is estimated how much other elements zirconium, uranium, americium and neptunium influence on plutonium phase stability. Afterwards it is needed that eutectic reaction is verified through experimental necessarily

  11. Synthesis and characterization of PbO-CdO nanocomposite and its effect on (Bi,Pb)-2223 superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Yahya, Nabil A.A. [Thamar University, Physics Department, Faculty of Education, Thamar (Yemen); Al-Gaashani, R. [Thamar University, Physics Department, Faculty of Education, Thamar (Yemen); Qatar Environment and Energy Research Institute (QEERI), Hamad Bin Khalifa University (HBKU), Doha (Qatar); Abd-Shukor, R. [Universiti Kebangsaan Malaysia, School of Applied Physics, Bangi, Selangor (Malaysia)

    2017-03-15

    A PbO-CdO nanocomposite-added Bi{sub 1.6}Pb{sub 0.4}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} ((Bi,Pb)-2223) superconductor has been prepared. The effect of the PbO-CdO nanocomposite addition on the transport critical current density (J{sub c}) of (Bi,Pb)-2223 superconductor was investigated. The transition temperature (T{sub c-onset}), zero electrical resistance temperature (T{sub c-R=0}), and J{sub c} of the samples were measured by the four-probe method. Phase formation, structure, and microstructure of samples were investigated. The distribution of nanoparticle size was determined. The results indicated that the PbO-CdO-added samples showed larger grain size and an increased volume fraction of high-T{sub c} phase (Bi-2223) compared to the non-added sample. A slight increase in T{sub c-R=0} of x = 0.15 wt% was observed. J{sub c} of the PbO-CdO nanocomposite-added samples was significantly higher than for the non-added sample. That could be explained by the possibility that the PbO-CdO nanocomposite acts as an effective flux pinning center in (Bi,Pb)-2223. At 77 K, J{sub c} of x = 0.15 wt% added sample was more than 20 times larger than J{sub c} of the non-added sample (x = 0 wt%). A combined effect of enhanced flux pinning, increased fraction of high-T{sub c} phase and improved grain size, which led to increase in the J{sub c} of added samples, is discussed. (orig.)

  12. Crystallization processes in Ni-Ti-B glassy alloys of near-ternary-eutectic composition

    International Nuclear Information System (INIS)

    Merk, N.; Morris, D.G.; Stadelmann, P.

    1987-01-01

    The crystallization kinetics and mechanisms of three Ni-Ti-B glasses have been examined with a view to elucidating the roles of chemical composition and quenched structure on behaviour. Alloys of composition near a ternary-eutectic point have been chosen because they represent a real and complex situation where several crystalline phases may form simultaneously. Crystallization processes are analysed in terms of nucleation and growth stages. Different nucleation mechanisms seem to be best explained in terms of the short range ordered structure of the quenched glass. Analysis of crystal glass interface energies indicates that it is not this energy term which controls the nucleation of crystals on annealing. Crystal growth may involve a eutectic mechanism or a single-phase mechanism controlled by interface or matrix-diffusion kinetics. Crystallization is fastest when eutectic nucleation and growth occurs. Formation of the eutectic colony requires the initial formation of the phase of complex structure followed by the phase of simpler structure

  13. Electrochemical study and recovery of Pb using 1:2 choline chloride/urea deep eutectic solvent: A variety of Pb species PbSO4, PbO2, and PbO exhibits the analogous thermodynamic behavior

    International Nuclear Information System (INIS)

    Liao, Yu-Shun; Chen, Po-Yu; Sun, I-Wen

    2016-01-01

    Water-insoluble PbSO 4 , PbO 2 , and PbO are fairly soluble in choline chloride/urea deep eutectic solvent (ChCl/urea DES) in 1:2 molar ratio. Very interestingly, solution prepared from PbO 2 exhibits the almost identical electrochemical behavior as those from PbSO 4 and PbO, indicating that Pb(II) is formed in the DES regardless of what Pb compound is introduced. The electrochemical reduction of the Pb(II) species is determined as an irreversible process, and involves the three-dimensional (3D) instantaneous nucleation with diffusion-controlled growth. From the dependence of the diffusion coefficient on temperature, the activation energy for diffusion of PbSO 4 and PbO 2 is determined to be 33.7 and 34.1 kJ mol −1 , respectively. Electrodeposition of Pb was achieved potentiostatically and galvanostatically. The surface morphology of Pb deposits significantly depends on the applied potential and current. The coulombic efficiency of Pb electrodeposition is higher than 90%. Electrodeposition of Pb from a wet DES containing a mixture of three different Pb sources is also investigated. The XRD analysis confirmed that the electrodeposits consisted of metallic Pb.

  14. Preparation of nickel-based amorphous alloys with finely dispersed lead and lead-bismuth particles and their superconducting properties

    International Nuclear Information System (INIS)

    Inoue, A.; Oguchi, M.; Harakawa, Y.; Masumoto, T.; Matsuzaki, K.

    1986-01-01

    The application of the melt-quenching technique to Ni-Si-B-Pb, Ni-P-B-Pb, Ni-Si-B-Pb-Bi and Ni-P-B-Pb-Bi alloys containing immiscible elements such as lead and bismuth has been tried and it has been found to result in the formation of a new type of material consisting of fine fcc Pb or hcp epsilon(Pb-Bi) + bct X(Pb-Bi) particles dispersed uniformly in the nickel-based amorphous matrix. The particle size and interparticle distance were 1 to 3 and 1 to 4 μm, respectively, for the lead phase, and less than 0.2 to 0.5 μm and 0.2 to 1.0 μm for the Pb-Bi phase. The uniform dispersion of such fine particles into the amorphous matrix was achieved in the composition range below about 6 at% Pb and 7 at% (Pb+Bi). Additionally, these amorphous alloys have been found to exhibit a superconductivity by the proximity effect of fcc Pb or epsilon(Pb-Bi) superconducting particles. The transition temperature Tsub(c) was in the range 6.8 to 7.5 K for the Ni-Si (or P)-B-Pb alloys and 8.6 to 8.8 K for the Ni-Si (or P)-B-Pb-Bi alloys. The upper critical field Hsub(c2) and the critical current density Jsub(c) for (Nisub(0.8)Psub(0.1)Bsub(0.1)) 95 Pb 3 Bi 2 at 4.2 K were, respectively, about 1.6 T and of the order of 7 x 10 7 Am -2 at zero applied field. (author)

  15. The crystal structure of Kirkiite, Pb10Bi3As3S19

    DEFF Research Database (Denmark)

    Makovicky, Emil; Balic Zunic, Tonci; Karanovic, Ljiljana

    2006-01-01

    and chemical analysis resulted in comparable formulae, Pb10Bi2.16As3.84S19 and Pb10.08Bi2.55Sb0.13As2.91S19, respectively, which are close to the ideal formula Pb10Bi3As3S19. The crystal lattice shows a pseudohexagonal symmetry, which is the cause of common twinning in this mineral. The main twin-law has (20...... layers parallel to (083) of kirkiite; the slabs are unit-cell-twinned on (010) refl ection planes. The structure contains one split As position, and two additional sites that could accommodate both As and Bi. The As,Bi distribution over these two sites is determined by the trapezoidal distortion...... of the half-octahedral coordination environment inside the tightly bonded double layers of the PbS-SnS archetype slabs. Owing to the stoichiometry requirements in this structure, Bi must also substitute for 1/11 of the Pb sites. Bond-valence calculations and the volumes of coordination polyhedra show...

  16. SULFURIC ACID CORROSION OF LOW Sb - Pb BATTERY ALLOYS

    African Journals Online (AJOL)

    user

    1983-09-01

    Sep 1, 1983 ... (Manuscript received February,1983). ABSTRACT. The corrosion properties of low Sb - Pb alloys developed for maintenance free motive power industrial batteries was studied by a bare grid constant current method and compared to those of the conventional. Pb- 6% Sb alloy. Low Sb-Pb alloys with Se and ...

  17. Modulation-free bismuth-lead cuprate superconductors: BiPbSr1+xL1-xCuO6 and BiPbSr2Y1-xCaxCu2O8

    International Nuclear Information System (INIS)

    Manivannan, V.; Gopalakrishnan, J.; Rao, C.N.R.

    1991-01-01

    Modulation-free BiPbSrLCuO 6 (L=La, Pr, Nd) and BiPbSr 2 YCu 2 O 8 , which are isotypic with the n=1 and 2 members of the Bi 2 Sr 2 Ca n-1 Cu n O 2n+4 family, have been prepared and characterized. These parent compounds are nonsuperconducting, but when doped with holes by substitution chemistry give modulation-free superconducting cuprates of the general formulas BiPbSr 1+xL1-x CuO 6 and BiPbSr 2 Y 1-x Ca x Cu 2 O 8 , exhibiting maximum T c 's of 24 and 85 K, respectively. Significantly, the hole concentration at the maximum T c is 0.12 in the cuprate family with a single Cu-O layer and 0.22 in that with two Cu-O layers

  18. Characterization of age-hardening behavior of eutectic region in squeeze-cast A356-T5 alloy using nanoindenter and atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Youn, S.W. [Advanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564 (Japan)]. E-mail: youn.sung-won@aist.go.jp; Kang, C.G. [National Laboratory of Thixo/Rheo Forming, School of Mechanical Engineering, Pusan National University, Busan (Korea, Republic of)]. E-mail: cgkang@pusan.ac.kr

    2006-06-15

    The nano/microstructure, the aging response (in T5 heat treatment), and the mechanical/tribological properties of the eutectic regions in squeeze-cast A356 alloy parts were investigated using nano/micro-indentation and mechanical scratching, combined with optical microscopy and atomic force microscope (AFM). Most eutectic Si crystals in the A356 alloy showed a modified morphology as fine-fibers. The loading curve for the eutectic region was more irregular than that of the primary Al region due to the presence of various particles of varying strength. In addition, the eutectic region showed lower pile-up and higher elastic recovery than the primary Al region. The aging responses of the eutectic regions in the squeeze-cast A356 alloys aged at 150 deg. C for different times (0, 2, 4, 8, 10, 16, 24, 36, and 72 h) were investigated. As the aging time increased, acicular Si particles in the eutectic regions gradually came to a fine structure. Both Vickers hardness (H {sub V}) and indentation (H {sub IT}) test results showed almost the same trend of aging curves, and the peak was obtained at the same aging time of 10 h. A remarkable size-dependence of the tests was found. The friction coefficient for the eutectic region was lower than that for the primary Al region.

  19. Thermal Fatigue Evaluation of Pb-Free Solder Joints: Results, Lessons Learned, and Future Trends

    Science.gov (United States)

    Coyle, Richard J.; Sweatman, Keith; Arfaei, Babak

    2015-09-01

    Thermal fatigue is a major source of failure of solder joints in surface mount electronic components and it is critically important in high reliability applications such as telecommunication, military, and aeronautics. The electronic packaging industry has seen an increase in the number of Pb-free solder alloy choices beyond the common near-eutectic Sn-Ag-Cu alloys first established as replacements for eutectic SnPb. This paper discusses the results from Pb-free solder joint reliability programs sponsored by two industry consortia. The characteristic life in accelerated thermal cycling is reported for 12 different Pb-free solder alloys and a SnPb control in 9 different accelerated thermal cycling test profiles in terms of the effects of component type, accelerated thermal cycling profile and dwell time. Microstructural analysis on assembled and failed samples was performed to investigate the effect of initial microstructure and its evolution during accelerated thermal cycling test. A significant finding from the study is that the beneficial effect of Ag on accelerated thermal cycling reliability (measured by characteristic lifetime) diminishes as the severity of the accelerated thermal cycling, defined by greater ΔT, higher peak temperature, and longer dwell time increases. The results also indicate that all the Pb-free solders are more reliable in accelerated thermal cycling than the SnPb alloy they have replaced. Suggestions are made for future work, particularly with respect to the continued evolution of alloy development for emerging application requirements and the value of using advanced analytical methods to provide a better understanding of the effect of microstructure and its evolution on accelerated thermal cycling performance.

  20. Brazing characteristics of a Zr-Ti-Cu-Fe eutectic alloy filler metal for Zircaloy-4

    Science.gov (United States)

    Lee, Jung G.; Lim, C. H.; Kim, K. H.; Park, S. S.; Lee, M. K.; Rhee, C. K.

    2013-10-01

    A Zr-Ti-Cu-Fe quaternary eutectic alloy was employed as a new Be-free brazing filler metal for Zircaloy-4 to supersede physically vapor-deposited Be coatings used conventionally with several disadvantages. The quaternary eutectic composition of Zr58Ti16Cu10Fe16 (at.%) showing a low melting temperature range from 832 °C to 853 °C was designed by a partial substitution of Zr with Ti based on a Zr-Cu-Fe ternary eutectic system. By applying an alloy ribbon with the determined composition, a highly reliable joint was obtained with a homogeneous formation of predominantly grown α-Zr phases owing to a complete isothermal solidification, exhibiting strength higher than that of Zircaloy-4. The homogenization of the joint was rate-controlled by the diffusion of the filler elements (Ti, Cu, and Fe) into the Zircaloy-4 base metal, and the detrimental segregation of the Zr2Fe phase in the central zone was completely eliminated by an isothermal holding at a brazing temperature of 920 °C for 10 min.

  1. Corrosion of ferrous alloys in eutectic lead-lithium environments

    International Nuclear Information System (INIS)

    Chopra, O.K.; Smith, D.L.

    1983-09-01

    Corrosion data have been obtained on austenitic prime candidate alloy (PCA) and Type 316 stainless steel and ferritic HT-9 and Fe-9Cr-1Mo steels in a flowing Pb-17 at. % Li environment at 727 and 700 K (454 and 427 0 C). The results indicate that the dissolution rates for both austenitic and ferritic steels in Pb-17Li are an order of magnitude greater than in flowing lithium. The influence of time, temperature, and alloy composition on the corrosion behavior in Pb-17Li is similar to that in lithium. The weight losses for the austenitic steels are an order of magnitude greater than for the ferritic steels. The rate of weight loss for the ferritic steels is constant, whereas the dissolution rates for the austenitic steels decrease with time. After exposure to Pb-17Li, the austenitic steels develop a very weak and porous ferrite layer which easily spalls from the specimen surface

  2. Determining metal ion distributions using resonant scattering at very high-energy K-edges: Bi/Pb in Pb{sub 5}Bi{sub 6}Se{sub 14}

    Energy Technology Data Exchange (ETDEWEB)

    Yuegang, Zhang; Lee, P L; Shastri, S D; Deming, Shu [Argonne National Lab., IL (United States). XOR, Advanced Photon Source; Wilkinson, A P [Georgia Inst. of Tech., Atlanta (United States). School of Chemistry and Biochemistry; Duck-Young, Chung; Kanatzidis, M G [Michigan State Univ., East Lansing (United States). Dept. of Chemistry

    2005-06-01

    Powder diffraction data collected at {proportional_to} 86 keV, and just below both the Pb and the Bi K-edges, on an imaging plate detector using synchrotron radiation from the Advanced Photon Source have been used to examine the Pb/Bi distribution over the 11 crystallographically distinct sites in Pb{sub 5}Bi{sub 6}Se{sub 14} [space group P2{sub 1}/m, a=16.0096(2) Aa, b=4.20148(4) Aa, c=21.5689(3) Aa and {beta}=97.537(1){sup 0}]. The scattering factors needed for the analyses were determined both by Kramers- Kronig transformation of absorption spectra and by analyses of diffraction patterns from reference compounds. Even with the relatively low scattering contrast that is available at the K-edges, it was possible to determine the Pb/Bi distribution and probe the presence of cation site vacancies in the material. The current results indicate that resonant scattering measurements at high-energy K-edges are a viable, and perhaps preferable, route to site occupancies when absorption from the sample or sample environment/container is a major barrier to the acquisition of high-quality resonant scattering data at lower-energy edges.

  3. X-ray fluorescence determination of Sn, Sb, Pb in lead-based bearing alloys using a solution technique

    Science.gov (United States)

    Tian, Lunfu; Wang, Lili; Gao, Wei; Weng, Xiaodong; Liu, Jianhui; Zou, Deshuang; Dai, Yichun; Huang, Shuke

    2018-03-01

    For the quantitative analysis of the principal elements in lead-antimony-tin alloys, directly X-ray fluorescence (XRF) method using solid metal disks introduces considerable errors due to the microstructure inhomogeneity. To solve this problem, an aqueous solution XRF method is proposed for determining major amounts of Sb, Sn, Pb in lead-based bearing alloys. The alloy samples were dissolved by a mixture of nitric acid and tartaric acid to eliminated the effects of microstructure of these alloys on the XRF analysis. Rh Compton scattering was used as internal standard for Sb and Sn, and Bi was added as internal standard for Pb, to correct for matrix effects, instrumental and operational variations. High-purity lead, antimony and tin were used to prepare synthetic standards. Using these standards, calibration curves were constructed for the three elements after optimizing the spectrometer parameters. The method has been successfully applied to the analysis of lead-based bearing alloys and is more rapid than classical titration methods normally used. The determination results are consistent with certified values or those obtained by titrations.

  4. Electrodeposition of bismuth alloys by the controlled potential method

    International Nuclear Information System (INIS)

    Lopez Alvarez, F.A.

    1993-01-01

    We worked with the electrodeposition of three bismuth alloys, the composition of the first electrolyte was: 0.3 g/l. Bi; 20 g/l. Ni; and the conditions were pH = 5.2 - 5.6; T = 25 Centigrade degrees; current density 0.3 A / dm 2 - 6.6 A / dm 2 . Following alloy was between Bi - Pb, composition of the electrolyte was 3.18 g/l. Bi (metallic); 31.81 g/l. Pb (Pb(NO 3 ) 2 ) pH : 1; T = 20 Centigrade degrees; current density 10.20 A/dm 2 . The third electrolyte was Bi-Cu, its composition was: 20.89 g/l. Bi; (metallic) 63.54 g/l Cu (Cu(NO 3 ) 2 ) pH : 1.5 - 1.8; T = 25-30 Centigrade degrees; current density 1-2 A/dm 2 . The best results were obtained with the third electrolyte. The purpose of this work was to experiment with different parameters like temperature, pH and the electrolyte concentration to obtain a bismuth alloy. (Author)

  5. Topological Weyl semimetals in Bi1 -xSbx alloys

    Science.gov (United States)

    Su, Yu-Hsin; Shi, Wujun; Felser, Claudia; Sun, Yan

    2018-04-01

    We investigated Weyl semimetal (WSM) phases in bismuth antimony (Bi1 -xSbx ) alloys by combination of atomic composition and arrangement. Via first-principles calculations, we found two WSM states with Sb concentrations of x =0.5 and 0.83 with specific inversion-symmetry-broken elemental arrangement. The Weyl points are close to the Fermi level in both of these two WSM states. Therefore, it is likely to obtain Weyl points in Bi-Sb alloy. The WSM phase provides a reasonable explanation for the current transport study of Bi-Sb alloy with the violation of Ohm's law [D. Shin, Y. Lee, M. Sasaki, Y. H. Jeong, F. Weickert, J. B. Betts, H.-J. Kim, K.-S. Kim, and J. Kim, Nat. Mater. 16, 1096 (2017), 10.1038/nmat4965]. This paper shows that the topological phases in Bi-Sb alloys depend on both elemental composition and their specific arrangement.

  6. Natural Radioisotopes of Pb, Bi and Po in the Atmosphere of Coal Burning Area

    Directory of Open Access Journals (Sweden)

    Asnor Azrin Sabuti

    2011-07-01

    Full Text Available This paper is discussing the changes of natural radionuclides 210Pb, 210Bi and 210Po in atmospheric samples (rainwater and solid fallout caused by Sultan Salahuddin Abdul Aziz coal-fired Power Plant (SSAAPP operation. We also describe the seasonal changes of 210Pb, 210Bi and 210Po to the monsoon seasons in Peninsular Malaysia. Bulk atmospheric trap was used to collect atmospheric samples for five months (7 Feb 2007 to 27 July 2007 and placed within the SSAAPP area. The natural radionuclide activity levels in the atmosphere were affected by local meteorological conditions to impact their variance over time. As a result, the natural radionulides were increased from the ambient value in atmospheric particles (solid fallout, which related to coal combustion by-product releases into atmosphere. In contrast, this was giving relatively lower or in the same magnitude from most places of radionuclides in rainwater samples. Degree of changes between 210Pb, 210Bi and 210Po affected by high temperature combustions were found to be different for each nuclide due to their respective volatility. 210Po in rainwater and solid fallout were considerably low during early inter-monsoon period which mainly controlled by the rainfall pattern. On the other hand, 210Pb and 210Bi in solid fallout were recorded higher concentrations which associated to drier conditions and more particulate content in air column during southwest monsoon. The mean activity ratio of 210BiRW/210PbRW and 210PoRW/210PbRW are 0.47 ± 0.04 and 0.52 ± 0.17, respectively. Whereas for 210BiSF/210PbSF and 210PoSF/210PbSF are 0.52 ± 0.05 and 0.71 ± 0.13, respectively. Some results showed high activity ratios, reaching to 1.87 ± 0.08 for 210Bi/210Pb and 4.58 ± 0.55 for 210Po/210Pb, of which due to additional of 210Bi and 210Po excess. These ratios also indicating that 210Pb and 210Bi could potentially come from the same source, compared to 210Po which varied differently, showing evidence it came

  7. Analysis of the residual strain change of Bi2212, Ag alloy and Ag during the heating and cooling process in Bi2212/Ag/Ag alloy composite wire

    International Nuclear Information System (INIS)

    Shin, J K; Ochiai, S; Okuda, H; Mukai, Y; Sugano, M; Sato, M; Oh, S S; Ha, D W; Kim, S C

    2008-01-01

    The residual strain change of Bi2212 and Ag during the cooling and heating process in the Bi2212/Ag/Ag alloy composite superconductor was studied. First, the residual strain of Bi2212 filaments at room temperature was measured by the x-ray diffraction method. Then, the Young's moduli of the constituents (Bi2212 filaments, Ag and Ag alloy) and yield strains of Ag and Ag alloy were estimated from the analysis of the measured stress-strain curve, based on the rule of mixtures. Also, the coefficient of thermal expansion of the Bi2212 filaments was estimated from the analysis of the measured thermal expansion curve of the composite wire. From the modeling analysis using the estimated property values and the residual strain of Bi2212 filaments, the changes of residual strain of Bi2212, Ag alloy and Ag with temperature during the cooling and heating process were revealed

  8. Thermoelectric properties and thermal stability of Bi-doped PbTe single crystal

    Science.gov (United States)

    Chen, Zhong; Li, Decong; Deng, Shuping; Tang, Yu; Sun, Luqi; Liu, Wenting; Shen, Lanxian; Yang, Peizhi; Deng, Shukang

    2018-06-01

    In this study, n-type Bi-doped single-crystal PbTe thermoelectric materials were prepared by melting and slow cooling method according to the stoichiometric ratio of Pb:Bi:Te = 1-x:x:1 (x = 0, 0.1, 0.15, 0.2, 0.25). The X-ray diffraction patterns of Pb1-xBixTe samples show that all main diffraction peaks are well matched with the PbTe matrix, which has a face-centered cubic structure with the space group Fm 3 bar m . Electron probe microanalysis reveals that Pb content decreases gradually, and Te content remains invariant basically with the increase of Bi content, indicating that Bi atoms are more likely to replace Pb atoms. Thermal analysis shows that the prepared samples possess relatively high thermal stability. Simultaneously, transmission electron microscopy and selected area electron diffraction pattern indicate that the prepared samples have typical single-crystal structures with good mechanical properties. Moreover, the electrical conductivity of the prepared samples improved significantly compared with that of the pure sample, and the maximum ZT value of 0.84 was obtained at 600 K by the sample with x = 0.2.

  9. Direct preparation of Al-base alloys from their oxides/metal precursors in the eutectic LiCl–KCl melt

    International Nuclear Information System (INIS)

    Gao, Bingliang; Zhu, Hao; Xia, Yuxiang; Shi, Zhongning; Hu, Xianwei; Wang, Zhaowen

    2016-01-01

    A study was carried out on the preparation of Al–Cu–Li alloy from their oxides/metal precursors using the method of electro-deoxidation in the eutectic LiCl–KCl melt at 648 K. Cyclic voltammetry was used to characterize the system. The samples were prepared by potentiostatic electrolysis at −1.0 V to −2.0 V (vs. Ag + /Ag) for 5 h. XRD analysis shows that Li 2 O is not electrochemically reduced to Li at −1.0 V (vs. Ag + /Ag) or more negative potential. During the preparation process of Al–Cu–Li alloy, lithium peroxide is formed as an intermediate compound. Al–Cu–Li alloy is chemically prepared through the reaction between aluminum and lithium peroxide by heating of Al–Cu–Li 2 O precursors in KCl–LiCl–LiF melt at 1023 K. Eelectro-deoxidation in LiCl–KCl melt can increase the lithium content in the final alloy product. Al–Mg and Al–Nd alloy were also prepared by using the same method from their mixture of aluminum and corresponding oxide, respectively. Al–Nd alloy can only be obtained at the temperature above 773 K. Al–Li alloy could not be obtained in eutectic CaCl 2 –LiCl melt because of formation of calcium aluminates. - Highlights: • Al–Cu–Li alloy was prepared using electrochemical deoxidation of Al–Cu–Li 2 O precursor in eutectic KCl–LiCl melt at 648 K. • Al–Nd alloy was successfully produced by the same method at 773 K. • CaCl 2 –LiCl melt is not a good choice for preparing Al–Li alloy because of formation of calcium aluminate.

  10. Direct preparation of Al-base alloys from their oxides/metal precursors in the eutectic LiCl–KCl melt

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Bingliang, E-mail: blgao@mail.neu.edu.cn; Zhu, Hao; Xia, Yuxiang; Shi, Zhongning; Hu, Xianwei; Wang, Zhaowen

    2016-04-25

    A study was carried out on the preparation of Al–Cu–Li alloy from their oxides/metal precursors using the method of electro-deoxidation in the eutectic LiCl–KCl melt at 648 K. Cyclic voltammetry was used to characterize the system. The samples were prepared by potentiostatic electrolysis at −1.0 V to −2.0 V (vs. Ag{sup +}/Ag) for 5 h. XRD analysis shows that Li{sub 2}O is not electrochemically reduced to Li at −1.0 V (vs. Ag{sup +}/Ag) or more negative potential. During the preparation process of Al–Cu–Li alloy, lithium peroxide is formed as an intermediate compound. Al–Cu–Li alloy is chemically prepared through the reaction between aluminum and lithium peroxide by heating of Al–Cu–Li{sub 2}O precursors in KCl–LiCl–LiF melt at 1023 K. Eelectro-deoxidation in LiCl–KCl melt can increase the lithium content in the final alloy product. Al–Mg and Al–Nd alloy were also prepared by using the same method from their mixture of aluminum and corresponding oxide, respectively. Al–Nd alloy can only be obtained at the temperature above 773 K. Al–Li alloy could not be obtained in eutectic CaCl{sub 2}–LiCl melt because of formation of calcium aluminates. - Highlights: • Al–Cu–Li alloy was prepared using electrochemical deoxidation of Al–Cu–Li{sub 2}O precursor in eutectic KCl–LiCl melt at 648 K. • Al–Nd alloy was successfully produced by the same method at 773 K. • CaCl{sub 2}–LiCl melt is not a good choice for preparing Al–Li alloy because of formation of calcium aluminate.

  11. Electronic tuning of the transport properties of off-stoichiometric PbxSn1−xTe thermoelectric alloys by Bi2Te3 doping

    International Nuclear Information System (INIS)

    Guttmann, Gilad M.; Dadon, David; Gelbstein, Yaniv

    2015-01-01

    The recent energy demands affected by the dilution of conventional energy resources and the growing awareness of environmental considerations had motivated many researchers to seek for novel renewable energy conversion methods. Thermoelectric direct conversion of thermal into electrical energies is such a method, in which common compositions include IV-VI semiconducting compounds (e.g., PbTe and SnTe) and their alloys. For approaching practical thermoelectric devices, the current research is focused on electronic optimization of off-stoichiometric p-type Pb x Sn 1−x Te alloys by tuning of Bi 2 Te 3 doping and/or SnTe alloying levels, while avoiding the less mechanically favorable Na dopant. It was shown that upon such doping/alloying, higher ZTs, compared to those of previously reported undoped Pb 0.5 Sn 0.5 Te alloy, were obtained at temperatures lower than 210–340 °C, depending of the exact doping/alloying level. It was demonstrated that upon optimal grading of the carrier concentration, a maximal thermoelectric efficiency enhancement of ∼38%, compared to that of an undoped material, is expected

  12. Continuous monitoring of the composition of liquid Pb-17Li eutectic using electrical resistivity methods

    International Nuclear Information System (INIS)

    Hubberstey, P.; Sample, T.; Barker, M.G.

    1991-01-01

    The composition of liquid Pb-17Li alloys has been continously determined, using an electrical resistivity monitor, during their interaction with nitrogen, oxygen, hydrogen and water vapour. The operation of the monitor depends on the fact that the resistivity of liquid Pb-Li alloys is dependent on their composition. Accurate resistivity-composition isotherms have been derived from resistivity-temperature data for 15 Pb-Li alloys (0 Li -8 Ω m (mol% Li) -1 at 725 K) is such that a change of 0.05 mol% Li in the alloy composition can be measured. The addition of oxygen and water vapour resulted in a decrease in the resistivity of the liquid alloy. Neither nitrogen nor hydrogen had any effect. The observed changes were shown to be consistent with Li 2 O formation. (orig.)

  13. A review of Pb-Sb(As-S, Cu(Ag-Fe(Zn-Sb(As-S, Ag(Pb-Bi(Sb-S and Pb-Bi-S(Te sulfosalt systems from the Boranja orefield, West Serbia

    Directory of Open Access Journals (Sweden)

    Radosavljević Slobodan A.

    2016-01-01

    Full Text Available Recent mineralogical, chemical, physical, and crystallographic investigations of the Boranja orefield showed very complex mineral associations and assemblages where sulfosalts have significant role. The sulfosalts of the Boranja orefield can be divided in four main groups: (i Pb-Sb(As-S system with ±Fe and ±Cu; (ii Cu(Ag-Fe(Zn-Sb(As-S system; (iii Ag(Pb-Bi(Sb-S; (iv and Pb-Bi-S(Te system. Spatially, these sulfosalts are widely spread, however, they are the most abundant in the following polymetallic deposits and ore zones: Cu(Bi-FeS Kram-Mlakva; Pb(Ag-Zn-FeS2 Veliki Majdan (Kolarica-Centralni revir-Kojići; Sb-Zn-Pb-As Rujevac; and Pb-Zn-FeS2-BaSO4 Bobija. The multi stage formation of minerals, from skarnhydrothermal to complex hydrothermal with various stages and sub-stages has been determined. All hydrothermal stages and sub-stages of various polymetallic deposits and ore zones within the Boranja orefield are followed by a variety of sulfosalts. [Projekat Ministarstva nauke Republike Srbije, br. OI-176016: Magmatism and geodynamics of the Balkan Peninsula from Mesozoic to present day: Significance for the formation of metallic and non-metallic mineral deposits

  14. Self-positioned thin Pb-alloy base electrode Josephson junction

    International Nuclear Information System (INIS)

    Kuroda, K.; Sato, K.

    1986-01-01

    A self-positioned thin (SPOT) Pb-alloy base electrode Josephson junction is developed. In this junction, a 50-nm thick Pb-alloy base electrode is restricted within the junction region on an Nb underlayer using a self-alignment technique. The grain size reduction and the base electrode area restriction greatly improve thermal cycling stability, where the thermal cycling tests of 4000 proposed junctions (5 x 5 μm 2 ) showed no failures after 4000 cycles. In addition, the elimination of insulator layer stress on the Pb-alloy base electrode rectifies the problem of size effect on current density. The Nb underlayers also serve to isolate the Pb-alloy base electrodes from the resistors

  15. Spectroscopy of 214Bi and systematics of 210,212,214Pb(0+) long->β-210,212,214Bi(0-)

    International Nuclear Information System (INIS)

    Berant, Z.; Schuhmann, R.B.; Alburger, D.E.; Chou, W.T.; Gill, R.L.; Warburton, E.K.; Wesselborg, C.

    1991-01-01

    Experiments designed to provide more information on the spectroscopy of 214 Bi, and on 214 Pb(β - ) 214 Bi in particular, were undertaken because of interest in first-forbidden β decay in the lead region. The experiments consisted of γ-γ coincidences and angular correlations, conversion electron measurements, level lifetime determinations, and precision γ-ray energy measurements. The 352-keV level of 214 Bi was found to be a strong candidate (and the only candidate) for the 0 1 - state. Recent additions to the 214 Pb decay scheme are confirmed by γ-γ coincidence measurements. A careful evaluation of the 214 Bi level scheme is made with emphasis on separating experimentally based conclusions from speculations based on systematics and other ''weak'' arguments. Shell-model calculations of the spectroscopy of 210,212 Bi and 210,212 Pb(β - ) 210,212 Bi were performed using a modification of the Kuo-Herling realistic interaction. These calculations and a generalized seniority model provide a basis for an examination of the systematics of the A=210, 212, 214 spectroscopy and β decay. The generalized seniority model is found to be a quite good approximation which provides a quantitative understanding of the 214 Pb decay rates

  16. Discharge behaviour of Mg-Al-Pb and Mg-Al-Pb-In alloys as anodes for Mg-air battery

    International Nuclear Information System (INIS)

    Wang, Naiguang; Wang, Richu; Peng, Chaoqun; Peng, Bing; Feng, Yan; Hu, Chengwang

    2014-01-01

    Highlights: • We investigate the effect of indium on the discharge behaviour of Mg-Al-Pb alloy. • We evaluate the performance of Mg-air batteries with Mg-Al-Pb and Mg-Al-Pb-In anodes. • We analyze the activation mechanism of Mg-Al-Pb-In alloy in the discharge process. - Abstract: The discharge behaviour of Mg-Al-Pb and Mg-Al-Pb-In alloys in 3.5 wt.% NaCl solution is investigated by electrochemical techniques, and compared with that of pure magnesium. The results show that Mg-Al-Pb-In alloy provides a more negative potential and exhibits a higher utilization efficiency in contrast with Mg-Al-Pb alloy and pure magnesium during the half-cell test at a large current density, and gives desirable discharge performance when used as anode for Mg- air battery. The peak power density of the Mg-air battery with Mg-Al-Pb-In anode is 94.5 mW cm −2 , which is comparable with those of Mg-H 2 O 2 semi-fuel batteries. Moreover, the activation mechanism of Mg-Al-Pb-In alloy during the discharge process is also analyzed

  17. Position annihilation study on the (Bi,Pb)-Sr-Ca-Cu-(O,F) superconductor

    International Nuclear Information System (INIS)

    Wang Xiaogang; Gao Xiaohui; Wang Ruidan; Hu Pingya

    1993-01-01

    In this note, we report the results of positron lifetime measurements in heat-treated (Bi, Pb)-Sr-Ca-Cu-(O, F), and discuss the possible location of the doped fluorine in the (Bi, Pb)-system superconductors. (orig.)

  18. Syntheses of the Bi(Pb)-2212 high-Tc superconductor through a novel oxide nitrate route

    International Nuclear Information System (INIS)

    Gibson, K; Ziegler, P; Meyer, H-J

    2004-01-01

    A novel route is presented for the syntheses of Bi 2 Sr 2 CaCu 2 O x (Bi-2212) and (Bi,Pb) 2 Sr 2 CaCu 2 O x (Bi,Pb-2212). Mixtures of oxides, nitrates and carbonates with approximate 2:2:1:2 metal ion compositions are dissolved in HNO 3 and dried at 200 deg. C in air. Afterwards they are reacted under their in situ generated NO x atmosphere in a closed reactor (Staurohr). This reaction forces the system to form the nitrate precursors (Bi,Sr,Ca) 2 O 2 NO 3 /CuO and (Bi,Pb,Sr,Ca) 2 O 2 NO 3 /CuO, respectively. In the final reaction stage these mixtures are converted into Bi(Pb)-2212 under NO x discharge in air. All important reaction stages and phase compositions are analysed by means of powder XRD

  19. Sulfuric Acid Corrosion of Low Sb - Pb Battery Alloys | Ntukogu ...

    African Journals Online (AJOL)

    The corrosion properties of low Sb - Pb alloys developed for maintenance free motive power industrial batteries was studied by a bare grid constant current method and compared to those of the conventional Pb- 6% Sb alloy. Low Sb-Pb alloys with Se and As grain refiners were found to have higher corrosion rates than the ...

  20. Preparation, characterization and thermoelectric properties of a polyaniline matrix Ge{sub 0.94}Pb{sub 0.01}Bi{sub 0.05}Te composite

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Sude; Zeng, Hao; Zhang, Changxing; Liu, Chun; Xu, Qian [Xihua Univ., Chengdu (China). Center for Advanced Materials and Energy; Zhang, Jianjun [Xihua Univ., Chengdu (China). School of Materials Science and Engineering

    2017-11-01

    In times of industrialization, much low temperature waste heat is released and no viable technology exists which can produce electricity from this low energy density heat. So the long sought-after class thermoelectric (TE) material which directly achieves conversion between thermal and electrical energy obtains much attention. However, the traditional TE materials are alloys of inorganic materials and expensive, and most of them have some level of toxicity, so the research on organic TE materials is very important. The polyaniline (PANI, i. e., a conducting polymer) and PANI matrix Ge{sub 0.94}Pb{sub 0.01}Bi{sub 0.05}Te composite material were prepared. The chemical structure, microstructure and thermoelectric properties were investigated by FTIR, XRD, SEM and ZEM. Results showed that the molecule chains in the PANI were not ranged very neatly, and Ge{sub 0.94}Pb{sub 0.01}Bi{sub 0.05}Te in the composite material formed interconnected network as 20 wt.-% Ge{sub 0.94}Pb{sub 0.01}Bi{sub 0.05}Te was added. Power factor of the composite material increased greatly while its ZT was almost two times of PANI. The addition of Ge{sub 0.94}Pb{sub 0.01}Bi{sub 0.05}Te was an effective method to increase the thermoelectric properties of PANI.

  1. Correlation between modulation structure and electronic inhomogeneity on Pb-doped Bi-2212 single crystals

    International Nuclear Information System (INIS)

    Sugimoto, A.; Kashiwaya, S.; Eisaki, H.; Yamaguchi, H.; Oka, K.; Kashiwaya, H.; Tsuchiura, H.; Tanaka, Y.

    2005-01-01

    The correlation between nanometer-size electronic states and surface structure is investigated by scanning tunneling microscopy/spectroscopy (STM/S) on Pb-doped Bi 2-x Pb x Sr 2 CaCu2O 8+y (Pb-Bi-2212) single crystals. The advantage of the Pb-Bi-2212 samples is that the modulation structure can be totally or locally suppressed depending on the Pb contents and annealing conditions. The superconducting gap (Δ) distribution on modulated Pb-Bi-2212 samples showed the lack of correlation with modulation structure except a slight reduction of superconducting island size for the b-axis direction. On the other hand, the optimal doped Pb-Bi-2212 (x = 0.6) samples obtained by reduced-annealing showed totally non-modulated structure in topography, however, the spatial distribution of Δ still showed inhomogeneity of which features were quite similar to those of modulated samples. These results suggest that the modulation structure is not the dominant origin of inhomogeneity although it modifies the streaky Δ structure sub-dominantly. From the gap structure variation around the border of narrow gap and broad gap regions, a trend of the coexistence of two separated phases i.e., superconducting phase and pseudogap like phase, is detected

  2. Proceedings of 'workshop on Pb-alloy cooled fast reactor'

    International Nuclear Information System (INIS)

    Kim, Sang Ji; Kim, Yong Hee; Hong, Ser Gi

    2003-06-01

    The objective of 'Workshop on Pb-Alloy Cooled Fast Reactor', held in Taejeon, Korea on May 6, 2003, is to enhance the basic knowledge in this area by facilitating the exchange of information and discussions about problematic area of design aspects. There were five presentations from three different countries and about 25 participants gathered during the workshop. The topics covered in the workshop include benefits and drawbacks of Pb-alloy and Sodium coolant, two Pb-alloy cooled 900 MWt reactor designs using both B4C rods and NSTs, BREST-300 breakeven reactor and transmutation effectiveness of LLFPs in the typical thermal/fast neutron systems. The generic conclusion for the Pb-alloy cooled fast reactor from this workshop is as follows: 1) It has a potential to satisfy the goals established for the Generation-IV reactor concepts, so it has a bright future. 2) As a fast neutron system with a moderate breeding or a conversion, it is flexible in its roles and has superior safety characteristics over sodium coolant because of Pb-alloy's chemical inertness with water/air and high boiling temperature

  3. Liquid-liquid structure transition and nucleation in undercooled Co-B eutectic alloys

    Energy Technology Data Exchange (ETDEWEB)

    He, Yixuan [Northwestern Polytechnical University, State Key Laboratory of Solidification Processing, Xi' an, Shanxi (China); Universite Grenoble Alpes, LNCMI, Grenoble (France); CNRS, LNCMI, Grenoble (France); Li, Jinshan; Wang, Jun; Kou, Hongchao [Northwestern Polytechnical University, State Key Laboratory of Solidification Processing, Xi' an, Shanxi (China); Beagunon, Eric [Universite Grenoble Alpes, LNCMI, Grenoble (France); CNRS, LNCMI, Grenoble (France)

    2017-06-15

    Cyclic superheating and cooling were carried out for the undercooled hypereutectic Co{sub 80}B{sub 20}, eutectic Co{sub 81.5}B{sub 18.5,} and hypoeutectic Co{sub 83}B{sub 17} alloys. For each alloy, there is a critical overheating temperature T{sub c}° at which there is a sharp increase of the mean undercooling, i.e., below (above) T{sub c}°, and the mean undercooling is about 80 °C (200 °C). DSC measurements show that there is a thermal absorption peak in the heating process, the peak temperature of which is nearly equal to the critical overheating temperature, indicating that the temperature-induced liquid-liquid structure transition does occur and should relate highly to nucleation in the undercooled Co-B eutectic melts. The effect of the liquid-liquid structure transition on nucleation was interpreted by the recent nucleation theory that considers the structures of overheated melts, and the composition-dependent overheating temperature was ascribed to the change of local favored structures. The present work provides further evidences for the liquid-liquid structure transition and is helpful for understanding solidification in undercooled melts. (orig.)

  4. Coupled growth of Al-Al2Cu eutectics in Al-Cu-Ag alloys

    International Nuclear Information System (INIS)

    Hecht, U; Witusiewicz, V; Drevermann, A

    2012-01-01

    Coupled eutectic growth of Al and Al 2 Cu was investigated in univariant Al-Cu-Ag alloys during solidification with planar and cellular morphology. Experiments reveal the dynamic selection of small spacings, below the minimum undercooling spacing and show that distinct morphological features pertain to nearly isotropic or anisotropic Al-Al 2 Cu interfaces.

  5. Lattice thermal transport in group II-alloyed PbTe

    Science.gov (United States)

    Xia, Yi; Hodges, James M.; Kanatzidis, Mercouri G.; Chan, Maria K. Y.

    2018-04-01

    PbTe, one of the most promising thermoelectric materials, has recently demonstrated a thermoelectric figure of merit (ZT) of above 2.0 when alloyed with group II elements. The improvements are due mainly to significant reduction of lattice thermal conductivity (κl), which was in turn attributed to nanoparticle precipitates. However, a fundamental understanding of various phonon scattering mechanisms within the bulk alloy is still lacking. In this work, we apply the newly-developed density-functional-theory-based compressive sensing lattice dynamics approach to model lattice heat transport in PbTe, MTe, and Pb0.94M0.06Te (M = Mg, Ca, Sr, and Ba) and compare our results with experimental measurements, with focus on the strain effect and mass disorder scattering. We find that (1) CaTe, SrTe, and BaTe in the rock-salt structure exhibit much higher κl than PbTe, while MgTe in the same structure shows anomalously low κl; (2) lattice heat transport of PbTe is extremely sensitive to static strain induced by alloying atoms in solid solution form; (3) mass disorder scattering plays a major role in reducing κl for Mg/Ca/Sr-alloyed PbTe through strongly suppressing the lifetimes of intermediate- and high-frequency phonons, while for Ba-alloyed PbTe, precipitated nanoparticles are also important.

  6. A comparative neutronic analysis of KALIMER breeder core using Na or Pb-Bi coolant

    International Nuclear Information System (INIS)

    Yoo, J. W.; Kim, S. J.; Kim, Y. I.

    2000-01-01

    A comparative neutronic study has been conducted on KALIMER breeder core according to the replacement of sodium coolant by Pb-Bi coolant. Since the atomic weight of Pb and Bi is about 9 times heavier than that of Na, the energy loss by neutron colliding with Pb-Bi nucleus will be very small. Therefore, the reactor with Pb-Bi coolant will have a harder neutron spectrum than that with Na coolant. Consequently, the breeding ratio and burnup reactivity swing is expected to be enhanced. In addition, when Pb-Bi coolant is voided, a negative coolant void coefficient can be obtained by the net effects of smaller spectrum hardening and large neutron leakage. As a result, the breeding ratio was increased from 1.18 to 1.23 and burnup reactivity swing was reduced from 631 pcm to 150 pcm. When the coolant in the whole region of active core is voided, the coolant void coefficient was found to be -539 and -264 pcm at BOEC and EOEC, respectively. In the local voided case, the smaller coolant void coefficient was obtained than that of Na coolant. Accordingly, the use of Pb-Bi coolant in KALIMER gives an advantage of higher breeding ratio, smaller burnup reactivity swing and negative coolant void coefficient without any significant degradation of nuclear performance

  7. Eutectic Al-Si-Cu-Fe-Mn alloys with enhanced mechanical properties at room and elevated temperature

    International Nuclear Information System (INIS)

    Wang, E.R.; Hui, X.D.; Chen, G.L.

    2011-01-01

    Highlights: → Fabricated a kind of high performance Al-Si alloy with low production costs. → Clarified two different morphologies of α-Fe and corresponding crystal structures. → Analyzed the crystallography of Cu-rich phases before and after T6 treatment. → Fracture mechanism of precipitates in experimental alloys during tensile process. -- Abstract: In this paper, we report a novel kind of eutectic Al-Si-Cu-Fe-Mn alloy with ultimate tensile strength up to 336 MPa and 144.3 MPa at room temperature and 300 o C, respectively. This kind of alloy was prepared by metal mold casting followed by T6 treatment. The microstructure is composed of eutectic and primary Si, α-Fe, Al 2 Cu and α-Al phases. Iron-rich phases, which were identified as BCC type of α-Fe (Al 15 (Fe,Mn) 3 Si 2 ), exist in blocky and dendrite forms. Tiny blocky Al 2 Cu crystals disperse in α-Fe dendrites or at the grain boundaries of α-Al. During T6 treatment, Cu atoms aggregate from the super-saturation solid solution to form GP zones, θ'' or θ'. Further analysis found that the enhanced mechanical properties of the experimental alloy are mainly attributed to the formation of α-Fe and copper-rich phases.

  8. Microstructure, mechanical properties, castability and in vitro biocompatibility of Ti-Bi alloys developed for dental applications.

    Science.gov (United States)

    Qiu, K J; Liu, Y; Zhou, F Y; Wang, B L; Li, L; Zheng, Y F; Liu, Y H

    2015-03-01

    In this study, the microstructure, mechanical properties, castability, electrochemical behaviors, cytotoxicity and hemocompatibility of Ti-Bi alloys with pure Ti as control were systematically investigated to assess their potential applications in the dental field. The experimental results showed that, except for the Ti-20Bi alloy, the microstructure of all other Ti-Bi alloys exhibit single α-Ti phase, while Ti-20Bi alloy is consisted of mainly α-Ti phase and a small amount of BiTi2 and BiTi3 phases. The tensile strength, hardness and wear resistance of Ti-Bi alloys were demonstrated to be improved monotonically with the increase of Bi content. The castability test showed that Ti-2Bi alloy increased the castability of pure Ti by 11.7%. The studied Ti-Bi alloys showed better corrosion resistance than pure Ti in both AS (artificial saliva) and ASFL (AS containing 0.2% NaF and 0.3% lactic acid) solutions. The concentrations of both Ti ion and Bi ion released from Ti-Bi alloys are extremely low in AS, ASF (AS containing 0.2% NaF) and ASL (AS containing 0.3% lactic acid) solutions. However, in ASFL solution, a large number of Ti and Bi ions are released. In addition, Ti-Bi alloys produced no significant deleterious effect to L929 cells and MG63 cells, similar to pure Ti, indicating a good in vitro biocompatibility. Besides, both L929 and MG63 cells perform excellent cell adhesion ability on Ti-Bi alloys. The hemolysis test exhibited that Ti-Bi alloys have an ultra-low hemolysis percentage below 1% and are considered nonhemolytic. To sum up, the Ti-2Bi alloy exhibits the optimal comprehensive performance and has great potential for dental applications. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  9. Divorced eutectic in a HPDC magnesium-aluminum alloy

    International Nuclear Information System (INIS)

    Barbagallo, S.; Laukli, H.I.; Lohne, O.; Cerri, E.

    2004-01-01

    The morphology of the eutectic in a thin-wall high pressure die cast (HPDC) U-shape AM60 magnesium box was investigated by light microscope, SEM, TEM and EPMA. The extremely fast cooling rate taking place in the solidification process produces a highly segregated zone near the boundaries of small grains and a fine distribution of β particles, which is typical of a completely divorced eutectic. It was shown that the segregated zone is coherent with the primary α-Mg grain core even if the increased aluminium content produces a deformation of the hexagonal crystal lattice, which was estimated through diffraction patterns (SADP). The variation of the alloying elements content through the grain boundaries was shown by means of EPMA line scanning. The β particle composition was quantitatively investigated and the results show that, in comparison with the equilibrium phase diagram, the non-equilibrium phase boundary of the Mg 17 Al 12 region is moved some percent towards the lower aluminium content, at the high cooling rate that occurs in high pressure die castings. The cubic structure of the β phase was revealed by diffraction pattern. The presence of small Al-Mn particles both inside the grain and in the boundary region was also put in evidence by TEM

  10. Oxidation kinetics of a Pb-64 at.% In single-phase alloy

    International Nuclear Information System (INIS)

    Zhang, M.X.; Chang, Y.A.; Marcotte, V.C.

    1991-01-01

    The solid-state oxidation kinetics of a Pb-64 at.% IN(50 wt.%) single-phase alloy were studied from room temperature to 150C using AES (Auger Electron Spectroscopy) depth profiling technique. The general oxidation behavior of this alloy is different from that of a Pb-3 at.% In alloy but similar to that of a Pb-30 at.% In alloy. The oxide formed on this alloy is almost pure In oxide (In 2 O 3 ) with the possible existence of some In suboxide near the oxide/alloy interface. At room temperature, oxidation of the alloy follows a direct logarithmic law, and the results can be described by the model proposed previously by Zhang, Chang, and Marcotte. At temperatures higher than 75C, rapid oxidation occurred initially followed by a slower parabolic oxidation at longer time. These data were described quantitatively by the model which assumes the existence of short-circuit diffusion in addition to lattice diffusion in the oxide as proposed by Smeltzer, Haering, and Kirkaldy. The effects of alloy composition in the oxidation kinetics of (pb, In) alloy are also examined by comparing the data for Pb-3, 30, and 64 at.% In alloys

  11. Transverse peltier effect in Pb-Bi{sub 2}Te{sub 3} multilayer structures

    Energy Technology Data Exchange (ETDEWEB)

    Reitmaier, Christina; Walther, Franziska; Kyarad, Amir; Lengfellner, Hans [University of Regensburg (Germany)

    2009-07-01

    Metal-semiconductor multilayer structures show, according to model calculations, large anisotropy in their electrical and thermal transport properties. Multilayer stacks consisting of alternating layers of Pb and n-type Bi{sub 2}Te{sub 3} and prepared by a heating procedure displayed large thermoelectric anisotropy up to {delta}S{approx}200 {mu} V/K, depending on the thickness ratio p=d{sub BiTe}/d{sub Pb}, where d{sub BiTe} and d{sub Pb} are the thicknesses of Bi{sub 2}Te{sub 3} and Pb layers, respectively. From multilayer stacks, tilted samples with layers inclined with respect to the sample surface where obtained by cutting stacks obliquely to the stack axis. Non-zero off-diagonal elements in the Seebeck-tensor describing the thermopower of tilted samples allow for the occurance of a transverse Peltier effect. Experimental results demonstrate cooling by the transverse Peltier effect and are compared to model calculations.

  12. Bi-induced band gap reduction in epitaxial InSbBi alloys

    Energy Technology Data Exchange (ETDEWEB)

    Rajpalke, M. K.; Linhart, W. M.; Birkett, M.; Alaria, J.; Veal, T. D., E-mail: T.Veal@liverpool.ac.uk [Stephenson Institute for Renewable Energy and Department of Physics, School of Physical Sciences, University of Liverpool, Liverpool L69 7ZF (United Kingdom); Yu, K. M. [Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States); Bomphrey, J. J.; Jones, T. S.; Ashwin, M. J., E-mail: M.J.Ashwin@warwick.ac.uk [Department of Chemistry, University of Warwick, Coventry CV4 7AL (United Kingdom); Sallis, S.; Piper, L. F. J. [Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States)

    2014-11-24

    The properties of molecular beam epitaxy-grown InSb{sub 1−x}Bi{sub x} alloys are investigated. Rutherford backscattering spectrometry shows that the Bi content increases from 0.6% for growth at 350 °C to 2.4% at 200 °C. X-ray diffraction indicates Bi-induced lattice dilation and suggests a zinc-blende InBi lattice parameter of 6.626 Å. Scanning electron microscopy reveals surface InSbBi nanostructures on the InSbBi films for the lowest growth temperatures, Bi droplets at intermediate temperatures, and smooth surfaces for the highest temperature. The room temperature optical absorption edge was found to change from 172 meV (7.2 μm) for InSb to ∼88 meV (14.1 μm) for InSb{sub 0.976}Bi{sub 0.024}, a reduction of ∼35 meV/%Bi.

  13. Nucleation-controlled microstructures and anomalous eutectic formation in undercooled Co-Sn and Ni-Si eutectic melts

    Science.gov (United States)

    Li, Mingjun; Kuribayashi, Kazuhiko

    2003-12-01

    Co-20.5 at. pct Sn and Ni-21.4 at. pct Si eutectic alloys have been levitated and undercooled in an electromagnetic levitator (EML) and then solidified spontaneously at different undercoolings. The original surface and cross-sectional morphologies of these solidified samples consist of separate eutectic colonies regardless of melt undercooling, indicating that microstructures in the free solidification of the eutectic systems are nucleation controlled. Regular lamellae always grow from the periphery of an independent anomalous eutectic grain in each eutectic colony. This typical morphology shows that the basic unit should be a single eutectic colony, when discussing the solidification behavior. Special emphasis is focused on the anomalous eutectic formation after a significant difference in linear kinetic coefficients is recognized for terminal eutectic phases, in particular when a eutectic reaction contains a nonfaceted disordered solid solution and a faceted ordered intermetallic compound as the terminal eutectic phases. It is this remarkable difference in the linear kinetic coefficients that leads to a pronounced difference in kinetic undercoolings. The sluggish kinetics in the interface atomic attachment of the intermetallic compound originates the occurrence of the decoupled growth of two eutectic phases. Hence, the current eutectic models are modified to incorporate kinetic undercooling, in order to account for the competitive growth behavior of eutectic phases in a single eutectic colony. The critical condition for generating the decoupled growth of eutectic phases is proposed. Further analysis reveals that a dimensionless critical undercooling may be appropriate to show the tendency for the anomalous eutectic-forming ability when considering the difference in linear kinetic coefficients of terminal eutectic phases. This qualitative criterion, albeit crude with several approximations and assumptions, can elucidate most of the published experimental results

  14. Local order and concentration fluctuations in K-Pb and Rb-Pb alloys

    International Nuclear Information System (INIS)

    Akinlade, O.

    1992-08-01

    The concentration fluctuations in the long wavelength limit S cc (0), short range order parameter and free energy of mixing of K-Pb and Rb-Pb alloys have been studied within the framework of the quasi-chemical theory. It is observed that the simple model could be used to shed more insight into the nature of chemical ordering that exists in such strongly compound forming binary alloys. (author). 19 refs, 6 figs, 1 tab

  15. Initial Stages of GaAs/Au Eutectic Alloy Formation for the Growth of GaAs Nano wires

    International Nuclear Information System (INIS)

    Rosnita, M.; Yussof, W.; Zuhairi, I.; Zulkafli, O.; Samsudi, S.

    2012-01-01

    Annealing temperature plays an important role in the formation of an Au-Ga eutectic alloy. The effects of the annealing temperature on gold nanoparticles colloid and substrate surface were studied using AFM, FE-SEM and TEM. At 600 degree Celsius, the layer of gold colloids particle formed an island in the state of molten eutectic alloy and absorbed evaporated metal-organics to formed nano wire (NW) underneath the alloy. Pit formed on the substrate surface due to the chemical reactions during the annealing process have an impact on the direction of growth of the NW. Without annealing, the NW formed vertically on the GaAs (100) surface. The growth direction depends on the original nucleation facets and surface energy when annealed. When annealed, the wire base is large and curved due to the migration of Ga atoms on the substrate surface towards the tip of the wire and the line tension between the substrate surface and gold particle. (author)

  16. Development of high temperature fasteners using directionally solidified eutectic alloys

    Science.gov (United States)

    George, F. D.

    1972-01-01

    The suitability of the eutectics for high temperature fasteners was investigated. Material properties were determined as a function of temperature, and included shear parallel and perpendicular to the growth direction and torsion parallel to it. Techniques for fabricating typical fastener shapes included grinding, creep forming, and direct casting. Both lamellar Ni3Al-Ni3Nb and fibrous (Co,Cr,Al)-(Cr,Co)7C3 alloys showed promise as candidate materials for high temperature fastener applications. A brief evaluation of the performance of the best fabricated fastener design was made.

  17. Ostwald ripening of Pb nanocrystalline phase in mechanically milled Al-Pb alloys and the influence of Cu additive

    International Nuclear Information System (INIS)

    Wu, Z.F.; Zeng, M.Q.; Ouyang, L.Z.; Zhang, X.P.; Zhu, M.

    2005-01-01

    The coarsening behavior of nanosized Pb phase in both Al-10%Pb and Al-10%Pb-4.5%Cu alloys has been studied by X-ray diffraction and transmission electron microscopy analysis. The coarsening of Pb nanophase in Al-Pb alloys still follows the classical ripening theory (the LSW theory) and the addition of Cu decreases the coarsening rate of Pb nanophase

  18. Phase formation in multicomponent monotectic aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mirkovic, Djordje; Groebner, Joachim; Schmid-Fetzer, Rainer [Institute of Metallurgy, Clausthal University of Technology (Germany)

    2008-07-01

    Alloys with a miscibility gap in the liquid state are potential materials for advanced bearings in automotive and other applications. While binary alloys, such as Al-Pb or Al-Bi, are well known, the information available for ternary monotectic Al-alloys is scarce. However, the phase formation in multicomponent alloys is not only more challenging from a scientific aspect, it is also a prerequisite for a focused development of advanced alloys. This motivated our detailed study of monotectic Al-Bi-Cu-Sn alloys including both experimental and computational thermodynamic methods. Based on the initially established systematic classification of monotectic ternary Al-alloys, the first promising monotectic reaction was observed in the ternary Al-Bi-Zn system. Further ternary systems Al-Cu-Sn, Al-Bi-Sn, Al-Bi-Cu and Bi-Cu-Sn were investigated as basis for quaternary Al-Bi-Cu-Sn alloys. Experimental investigations of phase equilibria, enthalpies and solidification microstructures were combined with thermodynamic modeling. The results demonstrate that the developed precise thermodynamic description is vital to reveal the distinct multicomponent monotectic features of pertinent phase diagrams. The solidification paths of ternary monotectic alloy systems, Al-Bi-Zn, Al-Sn-Cu and Al-Bi-Cu, were also studied using thermodynamic calculations, revealing specific details of phase formation during solidification of selected alloys.

  19. Development of metal-carbon eutectic cells for application as high temperature reference points in nuclear reactor severe accident tests: Results on the Fe-C, Co-C, Ti-C and Ru-C alloys' melting/freezing transformation temperature under electromagnetic induction heating

    International Nuclear Information System (INIS)

    Parga, Clemente J.; Journeau, Christophe; Parga, Clemente J.; Tokuhiro, Akira

    2012-01-01

    With the aim of reducing the high temperature measurement uncertainty of nuclear reactor severe accident experimental tests at the PLINIUS platform in Cadarache Research Centre, France, a variety of graphite cells containing a metal-carbon eutectic mix have been tested to assess the melting/freezing temperature reproducibility and their feasibility as calibration cells for thermometers. The eutectic cells have been thermally cycled in an induction furnace to assess the effect of heating/cooling rate, metal purity, graphite crucible design, and binary system constituents on the eutectic transformation temperature. A bi-chromatic pyrometer was used to perform temperature measurements in the graphite cell black cavity containing the metal-carbon eutectic mix. The eutectic points analyzed are all over 1100 C and cover an almost thousand degree span, i.e. from the Fe-Fe 3 C to the Ru-C eutectic. The induction heating permitted the attainment of heating and cooling rates of over 200 C/min under an inert atmosphere. The conducted tests allowed the determination of general trends and peculiarities of the solid. liquid transformation temperature under non-equilibrium and non-steady-state conditions of a variety of eutectic alloys (Fe-C, Co-C, Ti-C and Ru-C binary systems). (authors)

  20. Doping of (Bi,Pb)-2223 with metal oxides

    International Nuclear Information System (INIS)

    Goehring, D.; Vogt, M.; Wischert, W.; Kemmler-Sack, S.

    1997-01-01

    The effect of doping on formation, superconductivity and pinning forces of (Bi,Pb)-2223 was studied for several dopants. They can be subdivided into promoters (Cu, Mn at low doping level of x=0.1 and Rh) and inhibitors (Mg, Al, Sn, Co, Y, Pd and high substitution levels of Mn and Ni) of the transformation of the precursor material into (Bi,Pb)-2223. According to X-ray diffraction (XRD) studies the incorporation of the dopant into the 2223 lattice is restricted to a very low doping level. Higher dopant concentrations are accompanied by a segregation of secondary phases. These segregations are not effective in the process of creating flux pinning centres. A depression of T c is observed for 2223 materials with the dopants Co, Ni and Pd. (orig.)

  1. Equilibrium evaporation test of lead-bismuth eutectic and of tellurium in lead-bismuth

    International Nuclear Information System (INIS)

    Ohno, Shuji; Nishimura, Masahiro; Hamada, Hirotsugu; Miyahara, Shinya; Sasa, Toshinobu; Kurata, Yuji

    2005-01-01

    A series of equilibrium evaporation experiment was performed to acquire the essential and the fundamental knowledge about the transfer behavior of lead-bismuth eutectic (LBE) and impurity tellurium in LBE from liquid to gas phase. The experiments were conducted using the transpiration method in which saturated vapor in an isothermal evaporation pot was transported by inert carrier gas and collected outside of the pot. The size of the used evaporation pot is 8 cm inner diameter and 15 cm length. The weight of the LBE pool in the pot is about 500 g. The investigated temperature range was 450degC to 750degC. From this experiment and discussion using the data in literature, we have obtained several instructive and useful data on the LBE evaporation behavior such as saturated vapor pressure of LBE, vapor concentration of Pb, Bi and Bi 2 in LBE saturated gas phase, and activity coefficient of Pb in the LBE. The LBE vapor pressure equation is represented as the sum of Pb, Bi and Bi 2 vapor in the temperature range between 550degC and 750degC as logP[Pa]=10.2-10100/T[k]. The gas-liquid equilibrium partition coefficient of tellurium in LBE is in the range of 10 to 100, with no remarkable temperature dependency between 450degC and 750degC. This research was founded by the Ministry of Education, Culture, Sports, Science and Technology (MEXT). (author)

  2. Characterization of age-hardening behavior of eutectic surface on rheo-cast A356-T5 alloy by using nano/micro-indentation, scratching and atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Youn, S.W. [Department of Precision and Mechanical Engineering, Pusan National University, Pusan 609-735 (Korea, Republic of)]. E-mail: youn.sung-won@aist.go.jp; Kang, C.G. [National Research Laboratory of Thixo/Rheo Forming, School of Mechanical Engineering, Pusan National University, JangJun-Dong, Gumjung-Gu, Pusan 609-735 (Korea, Republic of)]. E-mail: cgkang@pusan.ac.kr

    2006-11-10

    This study investigates the nano/microstructure, the aging response (in T5 heat treatment), and the mechanical/tribological properties of the eutectic regions in rheo-cast A356 alloy parts using nano/micro-indentation and mechanical scratching, combined with optical microscopy and atomic force microscope (AFM). Most eutectic Si crystals in the A356 alloy showed a modified morphology as fine-fibers. The loading curve for the eutectic region was more irregular than that of the primary Al region due to the presence of various particles of varying strength. The aging responses of the eutectic regions in the rheo-cast A356 alloys aged at 150 deg. C for different times (0, 2, 4, 8, 10, 16, 24, 36, and 72 h) were investigated. Both Vickers hardness and indentation test results showed a similar trend of aging curves, and the peak was obtained at the same aging time of 10 h. A remarkable size-dependence of the tests was found. The friction coefficient for the eutectic region was lower than that for the primary Al region.

  3. Effects of Microalloying on the Microstructures and Mechanical Properties of Directionally Solidified Ni-33(at.%)Al-31Cr-3Mo Eutectic Alloys Investigated

    Science.gov (United States)

    Whittenberger, J. Daniel; Raj, Sai V.; Locci, Ivan E.; Salem, Jonathan A.

    2002-01-01

    Despite nickel aluminide (NiAl) alloys' attractive combination of oxidation and thermophysical properties, their development as replacements for superalloy airfoils in gas turbine engines has been largely limited by difficulties in developing alloys with an optimum combination of elevated-temperature creep resistance and room-temperature fracture toughness. Alternatively, research has focused on developing directionally solidified NiAl-based in situ eutectic composites composed of NiAl and (Cr,Mo) phases in order to obtain a desirable combination of properties a systematic investigation was undertaken at the NASA Glenn Research Center to examine the effects of small additions of 11 alloying elements (Co, Cu, Fe, Hf, Mn, Nb, Re, Si, Ta, Ti, and Zr) in amounts varying from 0.25 to 1.0 at.% on the elevated-temperature strength and room-temperature fracture toughness of directionally solidified Ni-33Al-31Cr-3Mo eutectic alloy. The alloys were grown at 12.7 mm/hr, where the unalloyed eutectic base alloy exhibited a planar eutectic microstructure. The different microstructures that formed because of these fifth-element additions are included in the table. The additions of these elements even in small amounts resulted in the formation of cellular microstructures, and in some cases, dendrites and third phases were observed. Most of these elemental additions did not improve either the elevated-temperature strength or the room-temperature fracture toughness over that of the base alloy. However, small improvements in the compression strength were observed between 1200 and 1400 K when 0.5 at.% Hf and 0.25 at.% Ti were added to the base alloy. The results of this study suggest that the microalloying of Ni-33Al-31Cr-3Mo will not significantly improve either its elevatedtemperature strength or its room-temperature fracture toughness. Thus, any improvements in these properties must be acquired by changing the processing conditions.

  4. Ultrasonic studies of aluminium-substituted Bi(Pb)-2223 superconductors

    Science.gov (United States)

    Solunke, M. B.; Sharma, P. U.; Pandya, M. P.; Lakhani, V. K.; Modi, K. B.; Venugopal Reddy, P.; Shah, S. S.

    2005-09-01

    The compositional dependence of elastic properties of Al^{3+}-substitu- ted Bi(Pb)-2223 superconducting system with the general formula Bi_{1.7-x}Al_xPb_{0.3}Sr_2Ca_2- Cu_3O_y (x = 0.0, 0.1, 0.2 and 0.3) have been studied by means of ultrasonic pulse transmission (UPT) technique at 1 MHz (300 K). The elastic moduli of the specimens are computed and corrected to zero porosity. The observed variation of elastic constants with aluminium substitution has been explained on the basis of the strength of interatomic bonding. The applicability of heterogeneous metal mixture rule for estimating elastic constants and transition temperature has been tested.

  5. Synthesis and crystal structure of Bi6.4Pb0.6P2O15.2

    International Nuclear Information System (INIS)

    Arumugam, N.; Lynch, V.; Steinfink, H.

    2007-01-01

    Bi 6.4 Pb 0.6 P 2 O 15.2 is a polymorph of structures with the general stoichiometry Bi 6+x M 1-x P 2 O 15+y . However, unlike previously published structures that consist of layers formed by edge sharing OBi 4 tetrahedra bridged by PO 4 and TO 6 (T=transition metal) tetrahedra and octahedra the title compound's structure is more complex. It is monoclinic, C2, a=19.4698(4) A, b=11.3692(3) A, c=16.3809(5) A, β=101.167(1) o , Z=10. Single-crystal X-ray diffraction data were refined by least squares on F 2 converging to R 1 =0.0387, wR 2 =0.0836 for 7023 intensities. The crystal twins by mirror reflection across (001) as the twin plane and twin component 1 equals 0.74(1). Oxygen ions are in tetrahedral coordination to four metal ions and the O(BiPb) 4 units share corners to form layers that are part of the three-dimensional framework. Eight oxygen ions form a cube around the two crystallographically independent Pb ions. Pb-O bond lengths vary from 2.265(14) to 2.869(14) A. Pairs of such cubes share an edge to form a Pb 3 O 20 unit. The two oxygen ions from the unshared edges are part of irregular Bi polyhedra. Other oxygen ions of Bi polyhedra are part only of O(BiPb) 4 units, and some oxygen ions of the polyhedra are also part of PO 4 tetrahedra. One, two, three and or four PO 4 moieties are connected to the Bi polyhedra. Bi-O bond lengths ≤3.1 A vary from 2.090(12) to 3.07(3) A. The articulations of Pb cubes, Bi polyhedra and PO 4 tetrahedra link into the three-dimensional structure. - Graphical abstract: View of the structure of Bi 6.4 Pb 0.6 P 2 O 15.2 parallel to the b-axis

  6. Improved mechanical properties of near-eutectic Al-Si piston alloy through ultrasonic melt treatment

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Jae-Gil; Lee, Sang-Hwa [Implementation Research Division, Korea Institute of Materials Science (KIMS), Changwon 51508 (Korea, Republic of); Lee, Jung-Moo, E-mail: jmoolee@kims.re.kr [Implementation Research Division, Korea Institute of Materials Science (KIMS), Changwon 51508 (Korea, Republic of); Cho, Young-Hee [Implementation Research Division, Korea Institute of Materials Science (KIMS), Changwon 51508 (Korea, Republic of); Kim, Su-Hyeon [Metal Materials Division, Korea Institute of Materials Science (KIMS), Changwon 51508 (Korea, Republic of); Yoon, Woon-Ha [Implementation Research Division, Korea Institute of Materials Science (KIMS), Changwon 51508 (Korea, Republic of)

    2016-07-04

    The effects of ultrasonic melt treatment (UST) on the microstructure and mechanical properties of Al-12.2Si-3.3Cu-2.4Ni-0.8Mg-0.1Fe (wt%) piston alloy were systematically investigated. Rigid colonies consisting of primary Si, eutectic Si, Mg{sub 2}Si and various aluminides (ε-Al{sub 3}Ni, δ-Al{sub 3}CuNi, π-Al{sub 8}FeMg{sub 3}Si{sub 6}, γ-Al{sub 7}Cu{sub 4}Ni, Q-Al{sub 5}Cu{sub 2}Mg{sub 8}Si{sub 6} and θ-Al{sub 2}Cu) were observed in the as-cast alloys. The sizes of the secondary phases, eutectic cell and grain were significantly decreased by UST because of the enhanced nucleation of each phase under ultrasonic irradiation. The yield strength, tensile strength and elongation at 25 °C were significantly improved by UST mainly because of the refinement of the microstructures. Both tensile strength and elongation at 350 °C were also improved by UST despite the unchanged yield strength.

  7. Real-time X-ray transmission microscopy for fundamental studies solidification: Al-Al2Au eutectic

    International Nuclear Information System (INIS)

    Curreri, Peter A.; Kaukler, William F.; Sen, Subhayu

    1998-01-01

    High resolution real-time X-ray Transmission Microscopy, XTM, has been applied to obtain information fundamental to solidification of optically opaque metallic systems. We have previously reported the measurement of the solute profile in the liquid, phase growth, and detailed solid-liquid interfacial morphology of aluminum based alloys with exposure times less than 2 seconds. Recent advances in XTM furnace design have provided an increase in real-time magnification (during solidification) for the XTM from 40X to 160X. The increased magnification has enabled for the first time the XTM imaging of real-time growth of fibers and particles with diameters of 5 μm. We have previously applied this system to study the kinetics of formation and morphological evolution of secondary fibers and particles in Al-Bi monotectic alloys. In this paper we present the preliminary results of the first real-time observations of fiber morphology evolution in optically opaque bulk metal sample of Aluminum-Gold eutectic alloy. These studies show that the XTM can be applied to study the fundamentals of eutectic and monotectic solidification. We are currently attempting to apply this technology in the fundamentals of solidification in microgravity

  8. Temperature-dependent viscosities of eutectic Al-Si alloys modified with Sr and P

    Energy Technology Data Exchange (ETDEWEB)

    Song Xigui [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan, 250061 (China)], E-mail: sxglm@126.com; Bian Xiufang; Zhang Jingxiang; Zhang Jie [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan, 250061 (China)

    2009-06-24

    The viscosities of eutectic Al-12 wt.%Si alloy and those modified with Sr and P were investigated using high-temperature torsional oscillation viscometer. Strontium decreased melt's viscosity, while phosphorus increased viscosity. Both additional level and means of addition affected the variation of viscosity. The activation energy of viscous flow was strengthened after modification, but the influence of modification on the molar volume was perplexing.

  9. Effect of Bi modification treatment on microstructure, tensile properties, and fracture behavior of cast Al-Mg2Si metal matrix composite

    Directory of Open Access Journals (Sweden)

    Wu Xiaofeng

    2013-01-01

    Full Text Available Bi has a good modification effect on the hypoeutectic Al-Si alloy, and the morphology of eutectic Si changes from coarse acicular to fine fibrous. Based on the similarity between Mg2Si and Si phases in crystalline structure and crystallization process, the present study investigated the effects of different concentrations of Bi on the microstructure, tensile properties, and fracture behavior of cast Al-15wt.%Mg2Si in-situ metal matrix composite. The results show that the addition of the proper amount of Bi has a significant modification effect on both primary and eutectic Mg2Si in the Al-15wt.%Mg2Si composite. With an increase in Bi content from 0 to 1wt.%, the morphology of the primary Mg2Si is changed from irregular or dendritic to polyhedral shape; and its average particle size is significantly decreased from 70 to 6 μm. Moreover, the morphology of the eutectic Mg2Si phase is altered from flake-like to very short fibrous or dot-like. When the Bi addition exceeds 4.0wt.%, the primary Mg2Si becomes coarse again. However, the eutectic Mg2Si still exhibits the modified morphology. Tensile tests reveal that the Bi addition can improve the tensile strength and ductility of the material. Compared with those of the unmodified composite, the ultimate tensile strength and percentage elongation after fracture with 1.0wt.% Bi increase 51.2% and 100%, respectively. At the same time, the Bi addition changes the fracture behavior from brittle to ductile.

  10. Interaction of hydrogen with Pb83Li17 eutectic alloy

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  11. Morphology and Hardness Improvement of Lead Bearing Alloy through Composite Production: 75Pb-15Sb-10Sn/ 15% V/V SiO2 Particulate Composite

    Directory of Open Access Journals (Sweden)

    Linus Okon ASUQUO

    2013-06-01

    Full Text Available The morphology and hardness improvement of lead bearing alloy through composite production: 75Pb-15Sb-10Sn/ 15%v/v SiO2 particulate composite, was studied. 75Pb-15Sb-10Sn white bearing alloy produced at the foundry shop of National Metallurgical Development Centre Jos was used for the production of the composite using stir-cast method. The reinforcing agent was 63 microns passing particles of silica. This was produced from pulverizing quartz using laboratory ball mill. The specimens of the composite produced were then subjected to metallographic to study the morphology of the structures produced both in the as cast and aged conditions of the composite. The samples were also tested for hardness and the result showed that the as cast composite had a hardness value of 33 HRB which is an improvement over the hardness value of 27.7 HRB for the 75Pb-15Sb-10Sn alloy which was used for the production of the composite. The effect of age hardening on the produced composite was also investigated; the result showed that the maximum hardness of 34 HRB was obtained after ageing for 3 hours. The micrographs revealed inter-metallic compound SbSn, eutectic of two solid solutions-one tin-rich and the other lead-rich, reinforcing particles, and solid solution of β. The results revealed that particle hardening can be used to improve the hardness of 75Pb-15Sb-10Sn white bearing alloy for use as heavy duty bearing material.

  12. Convenient hydrothermal decomposition process for preparation of nanocrystalline mineral Cu3BiS3 and Pb1-xBi2x/3S

    International Nuclear Information System (INIS)

    Hu Junqing; Deng Bin; Wang Chunrui; Tang Kaibin; Qian Yitai

    2003-01-01

    Mineral nanocrystalline Cu 3 BiS 3 and Pb 1-x Bi 2x/3 S (or Bi 0.22 Pb 0.89 S 1.22 ) have been prepared at low synthetic temperature of 100-150 deg. C by convenient hydrothermal decomposition process. X-ray powder diffraction, transmission electron microscopy, X-ray photoelectron spectra, and element analysis were used to characterize and measure the samples. The as-prepared Cu 3 BiS 3 sample consisted of whisker-like particles with an average size of 50x10 nm 2 and the Pb 1-x Bi 2x/3 S sample displayed aggregative particles with size in the range of 30-50 nm. Preliminary results showed that the prepared precursors, reaction temperature and time played a role in the formation of the final products. A possible reaction mechanism was also discussed briefly

  13. Safety design of Pb-Bi-cooled direct contact boiling water fast reactor (PBWFR)

    International Nuclear Information System (INIS)

    Takahashi, Minoru; Uchida, Shoji; Yamada, Yumi; Koyama, Kazuya

    2008-01-01

    In Pb-Bi-cooled direct contact boiling water small fast reactor (PBWFR), steam is generated by direct contact of feedwater with primary Pb-Bi coolant above the core, and Pb-Bi coolant is circulated by steam lift pump in chimneys. Safety design has been developed to show safety features of PBWFR. Negative void reactivity is inserted even if whole of the core and upper plenum are voided hypothetically by steam intrusion from above. The control rod ejection due to coolant pressure is prevented using in-vessel type control rod driving mechanism. At coolant leak from reactor vessel and feedwater pipes, Pb-Bi coolant level in the reactor vessel required for decay heat removal is kept using closed guard vessel. Dual pipes for feedwater are employed to avoid leak of water. Although there is no concern of loss of flow accident due to primary pump trip, feedwater pump trip initiates loss of coolant flow (LOF). Injection of high pressure water slows down the flow coast down of feedwater at the LOF event. The unprotected loss of flow and heat sink (ATWS) has been evaluated, which shows that the fuel temperatures are kept lower than the safety limits. (author)

  14. Chemical interaction of the In-Ga eutectic with Al and Al-base alloys

    International Nuclear Information System (INIS)

    Trenikhin, M.V.; Bubnov, A.V.; Duplyakin, V.K.; Nizovskij, A.I.

    2006-01-01

    The chemical interaction of the indium-gallium eutectic with Al and Al-base alloys is studied by X-ray diffraction, optical microscopy, and electron microscopy. Experimental data are presented that shed light on the reaction mechanism and the diffusion processes responsible for the subsequent disintegration of the material and its dissolution in water. Mechanical tests show that the activation of aluminum leads to a transition from plastic to brittle fracture [ru

  15. Influence of PbBi environment on the low-cycle fatigue behavior of SNS target container materials

    International Nuclear Information System (INIS)

    Kalkhof, D.; Grosse, M.

    2003-01-01

    The low-cycle fatigue (LCF) behavior of the stainless steel 316L and the 10.5Cr-steel Manet-II was investigated at 260 deg. C in air and in stagnant lead-bismuth (PbBi). At low-strain levels, the fatigue lives for 316L in PbBi and air were comparable. At total strain amplitudes of 0.50% and higher a weak influence of PbBi was observed. In contrast to 316L, the results of LCF tests for Manet-II in PbBi showed a significant reduction of lifetime for all applied strain amplitudes. In the worst case the cycle number to crack initiation was reduced by a factor of ∼7 compared with the comparable test in air. For the low-strain amplitude of 0.30%, fatigue tests conducted at a frequency of 0.1 Hz had shorter fatigue lives than at a frequency of 1.0 Hz. For Manet-II the crack propagation in PbBi was much faster than in air, and failure immediate followed the formation of the first macroscopic crack

  16. Effect of Substitutional Pb Doping on Bipolar and Lattice Thermal Conductivity in p-Type Bi0.48Sb1.52Te₃.

    Science.gov (United States)

    Kim, Hyun-Sik; Lee, Kyu Hyoung; Yoo, Joonyeon; Youn, Jehun; Roh, Jong Wook; Kim, Sang-Il; Kim, Sung Wng

    2017-07-06

    Cation substitutional doping is an effective approach to modifying the electronic and thermal transports in Bi₂Te₃-based thermoelectric alloys. Here we present a comprehensive analysis of the electrical and thermal conductivities of polycrystalline Pb-doped p-type bulk Bi 0.48 Sb 1.52 Te₃. Pb doping significantly increased the electrical conductivity up to ~2700 S/cm at x = 0.02 in Bi 0.48-x Pb x Sb 1.52 Te₃ due to the increase in hole carrier concentration. Even though the total thermal conductivity increased as Pb was added, due to the increased hole carrier concentration, the thermal conductivity was reduced by 14-22% if the contribution of the increased hole carrier concentration was excluded. To further understand the origin of reduction in the thermal conductivity, we first estimated the contribution of bipolar conduction to thermal conductivity from a two-parabolic band model, which is an extension of the single parabolic band model. Thereafter, the contribution of additional point defect scattering caused by Pb substitution (Pb in the cation site) was analyzed using the Debye-Callaway model. We found that Pb doping significantly suppressed both the bipolar thermal conduction and lattice thermal conductivity simultaneously, while the bipolar contribution to the total thermal conductivity reduction increased at high temperatures. At Pb doping of x = 0.02, the bipolar thermal conductivity decreased by ~30% from 0.47 W/mK to 0.33 W/mK at 480 K, which accounts for 70% of the total reduction.

  17. Directional solidification and characterization of the Al Nb2 - Al3 Nb eutectic system

    International Nuclear Information System (INIS)

    Trevisan, Eduardo A.O.; Andreotti, Fabio; Caram, Rubens

    1996-01-01

    The manufacturing of components to operate at high temperatures requires the use of metallic materials which can keep satisfactory mechanical and chemical properties, even at temperatures beyond 1000 deg C. An interesting alternative is the use of directionally solidified eutectic alloys. The eutectic alloy solidification makes possible the production of 'in situ' composite. A potentially useful system for manufacturing structural materials is the Al-Nb eutectic system. The aim of this work is to present the directional solidification of the Al-Nb eutectic alloy. (author)

  18. Tritium permeation barriers in contact with liquid lithium-lead eutectic (Pb-17Li)

    International Nuclear Information System (INIS)

    Forcey, K.S.; Perujo, A.

    1995-01-01

    The permeation of deuterium through coated stainless steel tubes containing liquid lithium-lead eutectic (Pb-17Li) has been studied and compared to measurements through tubes without the lithium compound. The measurements form part of an investigation into the effect of a potential tritium breeder material on permeation barriers for fusion reactors. The coatings studied were CVD TiC and Al 2 O 3 and a pack aluminised layer. Without the lithium-lead, the CVD coatings reduced the permeation rate up to 1 order of magnitude, and the aluminised layer up to 2 orders of magnitude. A CVD layer was unaffected by Pb-17Li whilst in the case of the aluminised tube, the lithium-lead completely removed the permeation barrier, presumably by attacking the surface oxide. Furthermore, the aluminised sample presented a large number of cracks and poor adheren ce to the substrate. ((orig.))

  19. The chemical fate of 212Bi-DOTA formed by β- decay of 212Pb(DOTA)2-

    International Nuclear Information System (INIS)

    Mirzadeh, S.; Kumar, K.; Gansow, O.A.

    1993-01-01

    The increasing use of inert metal complexes in radioimmunotherapy prompted us to explore the potential use of 212 Pb chelates. Herein, we report a study of the chemical fate of the 212 Bi-DOTA complex formed by β - decay of 212 Pb(DOTA) 2- (H 4 DOTA = 1,4,7,10-tetraazacyclododecanetetraacetic acid). To assure that both parent and daughter complexes were thermally stable, kinetic studies were performed with 203 Pb(II) and 206 Bi(III) which showed that both lead and bismuth complexes with DOTA undergo chemical exchange only very slowly in aqueous solution at pH 4-10. To investigate whether the complex ion which results from decay of 212 Pb(DOTA) 2- was intact and also stable, solutions initially containing only this ion were analyzed for amounts of DOTA-complexed and uncomplexed 212 Bi after attaining transient equilibrium with 212 Bi. The fraction of 212 Bi radioactivity not complexed to DOTA, vide infra, was found to be 36±2%. This value represents the fraction of breakup of 212 Bi(DOTA) - formed from β - decay of the parent complex. By considering the various extranuclear processes responsible for kinetic and electronic excitation of the 212 Bi daughter, break-up of the 212 Bi-DOTA complex is ascribed to the internal conversion of γ-rays emitted by the excited 212 Bi nuclide. (orig.)

  20. Magnetic properties in MnBi alloy of small crystallites for permanent magnet devices

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, S. K.; Prakash, H. R.; Ram, S., E-mail: jms.sanjeev@gmail.com [Materials Science Centre, Indian Institute of Technology, Kharagpur-721302 (India)

    2016-05-06

    A rare-earth free alloy like MnBi is a potential candidate for developing small magnets and devices. In a commercially viable method, a MnBi alloy was prepared by arc melting Mn and Bi metals in a 1:1 ratio. In terms of the X-ray diffraction a single crystalline MnBi phase is formed of the as prepared alloy. FESEM images delineate thin MnBi layers (25 – 40 nm thickness) of average EDX composition throughout the specimen. A large coercivity 5.501 kOe (6.5 emu/g magnetization) observed in an M-H at 300 K is decreased to 0.171 (9.0 emu/g magnetization) at 100 K in decreasing upon cooling.

  1. Preparation, heat treatment, and mechanical properties of the uranium-5 weight percent chromium eutectic alloy

    International Nuclear Information System (INIS)

    Townsend, A.B.

    1980-10-01

    The eutectic alloy of uranium-5 wt % chromium (U-5Cr) was prepared from high-purity materials and cast into 1-in.-thick ingots. This material was given several simple heat treatments, the mechanical properties of these heat-treated samples were determined; and the microstructure was examined. Some data on the melting point and transformation temperatures were obtained

  2. Preparation of porous lead from shape-controlled PbO bulk by in situ electrochemical reduction in ChCl-EG deep eutectic solvent

    Science.gov (United States)

    Ru, Juanjian; Hua, Yixin; Xu, Cunying; Li, Jian; Li, Yan; Wang, Ding; Zhou, Zhongren; Gong, Kai

    2015-12-01

    Porous lead with different shapes was firstly prepared from controlled geometries of solid PbO bulk by in situ electrochemical reduction in choline chloride-ethylene glycol deep eutectic solvents at cell voltage 2.5 V and 353 K. The electrochemical behavior of PbO powders on cavity microelectrode was investigated by cyclic voltammetry. It is indicated that solid PbO can be directly reduced to metal in the solvent and a nucleation loop is apparent. Constant voltage electrolysis demonstrates that PbO pellet can be completely converted to metal for 13 h, and the current efficiency and specific energy consumption are about 87.79% and 736.82 kWh t-1, respectively. With the electro-deoxidation progress on the pellet surface, the reduction rate reaches the fastest and decreases along the distance from surface to inner center. The morphologies of metallic products are porous and mainly consisted of uniform particles which connect with each other by finer strip-shaped grains to remain the geometry and macro size constant perfectly. In addition, an empirical model of the electro-deoxidation process from spherical PbO bulk to porous lead is also proposed. These findings provide a novel and simple route for the preparation of porous metals from oxide precursors in deep eutectic solvents at room temperature.

  3. Compatibility of 316L stainless steel with the liquid alloy Pb17Li

    International Nuclear Information System (INIS)

    Broc, M.; Fauvet, P.; Flament, T.; Terlain, A.; Sannier, J.

    1988-01-01

    The behavior of 316L austenitic stainless steel in liquid eutectic lead alloy is investigated. The 316L is a possible structural material for fusion reactors. The obtained results are summarized and compared with other experimental data. The mechanisms which control the corrosion process are discussed. The investigation shows that whatever, the hydraulic flow, the corrosion of 316L stainless steel exposed to Pb17Li is characterized by the formation of a porous ferritic layer. The corrosion kinetics is mainly dependent on temperature, hydraulic flow and metallurgical state of the steel. At 400 0 C in turbulent flow, the corrosion rate at steady state of 316L solution annealed is estimated to 27 microns/year to which a depth of 25 microns has to be added to take into account the initial transient period. From overall available results, dissolution and solid state transformation in case of turbulent flow and diffusion in liquid phase for laminar flow, may be suggested

  4. Phase-shift analysis of neutron-209Bi scattering and its comparison to neutron-208Pb scattering

    International Nuclear Information System (INIS)

    Chen, Z.P.; Tornow, W.; Walter, R.L.

    1995-01-01

    Published n- 209 Bi elastic differential cross-section, analyzing power, and total cross-section data in the energy range from 1.5 to 14 MeV were analyzed via a phase-shift analysis in order to find out whether these data show similar, unexplained resonance structures as observed recently for n- 208 Pb scattering. Although the n- 209 Bi and n- 208 Pb data are very similar, some of the phase shifts are quite different for the two systems. Only one resonancelike structure was observed for n- 209 Bi scattering in the excitation energy range from 9 to 18 MeV compared to eleven in the n- 208 Pb system, implying that n- 209 Bi data are probably more suitable than the classical n- 208 Pb system for detailed mean-field analyses approached through dispersion-relation optical models

  5. THE INFLUENCE OF HEAT TREATMENT WITH THE LIQUID PHASE ON FORMATION OF A MICROSTRUCTURE OF EUTECTIC Al-Si-ALLOY

    Directory of Open Access Journals (Sweden)

    A. Anikin

    2015-01-01

    Full Text Available The effect of heat treatment on the structure of the eutectic Al-Si-alloy, a theoretical substantiation process based on thermal analyzer and cooked microstructures was presented in this paper.

  6. Thermophysical properties of the Li(17)Pb(83) eutectic alloy

    International Nuclear Information System (INIS)

    Jauch, U.; Haase, G.; Schulz, B.

    1986-01-01

    Methods of measurements and results for the following properties of Li(17)Pb(83) are presented: density, specific heat, latent heat of fusion, surface energy, thermal conductivity and diffusivity, electrical conductivity and viscosity. The range of the temperature for extrapolation of the physical properties is discussed. (orig.)

  7. Study of the thermal and kinetic parameters during directional solidification of zinc-aluminum eutectic alloys

    International Nuclear Information System (INIS)

    Gueijman, Sergio Fabian; Ares, Alicia Esther; Schvezov, Carlos Enrique

    2008-01-01

    Much work has been done recently on investigating zinc-based binary alloys, with different aluminum content, and modified or not with small amounts of other alloying elements. Some of these alloys have interesting properties, such as, the ZA alloys that have properties similar to some bronzes that are used in applications that require pieces with enough resistance to mechanical stresses. The longitudinal thermal gradients, the minimal gradients, the velocities of the liquid interphases, the velocities of the solid interphases and the accelerations of both interphases as a function of time and position were determined for each diluted alloy of the eutectic concentration considered (Zn-5%Al, % in weight), solidified horizontally with caloric extraction from both ends of the test pieces. The values obtained from the horizontal solidification with two directions of predominant caloric extraction are compared to previous values obtained for the same vertically solidified alloy system with a predominantly caloric extraction direction

  8. The effect of intermetallic compound morphology on Cu diffusion in Sn-Ag and Sn-Pb solder bump on the Ni/Cu Under-bump metallization

    Science.gov (United States)

    Jang, Guh-Yaw; Duh, Jenq-Gong

    2005-01-01

    The eutectic Sn-Ag solder alloy is one of the candidates for the Pb-free solder, and Sn-Pb solder alloys are still widely used in today’s electronic packages. In this tudy, the interfacial reaction in the eutectic Sn-Ag and Sn-Pb solder joints was investigated with an assembly of a solder/Ni/Cu/Ti/Si3N4/Si multilayer structures. In the Sn-3.5Ag solder joints reflowed at 260°C, only the (Ni1-x,Cux)3Sn4 intermetallic compound (IMC) formed at the solder/Ni interface. For the Sn-37Pb solder reflowed at 225°C for one to ten cycles, only the (Ni1-x,Cux)3Sn4 IMC formed between the solder and the Ni/Cu under-bump metallization (UBM). Nevertheless, the (Cu1-y,Niy)6Sn5 IMC was observed in joints reflowed at 245°C after five cycles and at 265°C after three cycles. With the aid of microstructure evolution, quantitative analysis, and elemental distribution between the solder and Ni/Cu UBM, it was revealed that Cu content in the solder near the solder/IMC interface played an important role in the formation of the (Cu1-y,Niy)6Sn5 IMC. In addition, the diffusion behavior of Cu in eutectic Sn-Ag and Sn-Pb solders with the Ni/Cu UBM were probed and discussed. The atomic flux of Cu diffused through Ni was evaluated by detailed quantitative analysis in an electron probe microanalyzer (EPMA). During reflow, the atomic flux of Cu was on the order of 1016-1017 atoms/cm2sec in both the eutectic Sn-Ag and Sn-Pb systems.

  9. Tensile properties of several 800 MeV proton-irradiated bcc metals and alloys

    International Nuclear Information System (INIS)

    Brown, R.D.; Wechsler, M.S.; Tschalar, C.

    1987-01-01

    A spallation neutron source for the 600-MeV proton accelerator facility at the Swiss Institute for Nuclear Research (SIN) consists of a vertical cylinder filled with molten Pb-Bi. The proton beam enters the cylinder, passing upward through a window in contact with the Pb-Bi eutectic liquid that must retain reasonable strength and ductility upon irradiation at about 673 K to fluence of about 1 x 10/sup 25/ protons/m/sup 2/. Investigations are underway at the 800-MeV proton accelerator at the Los Alamos Meson Physics Facility (LAMPF) to test the performance of candidate SIN window materials under appropriate conditions of temperature, irradiation, and environment. Based on considerations of chemical compatibility with molten Pb-Bi, as well as interest in identifying fundamental radiation damage mechanisms, Fe, Ta, Fe-2.25Cr-1Mo, and Fe-12Cr-1Mo(HT-9) were chosen as candidate materials. Sheet tensile samples, 0.5-mm thick, of the four materials were fabricated and heat treated. The samples were sealed inside capsules containing Pb-Bi and were proton-irradiated at LAMPF to two fluences, 4.8 and 54 x 10/sup 23/ p/m/sup 2/. The beam current was approximately equal to the 1 mA anticipated for the upgraded SIN accelerator. The power deposited by the proton beam in the capsules was sufficient to maintain sample temperatures of about 673 K. Post-irradiation tensile tests were conducted at room temperature at a strain rate of 9 x 10/sup -4/s/sup -1/. The yield and ultimate strengths increased upon irradiation in all materials, while the ductility decreased, as indicated by the uniform strain. The pure metals, Ta and Fe, exhibited the greatest radiation hardening and embrittlement. The HT-9 alloy showed the smallest changes in strength and ductility. The increase in strength following irradiation is discussed in terms of a dispersed-barrier hardening model, for which the barrier sizes and formation cross sections are calculated

  10. Application of SEM/EBSD and FEG-TEM/CBED to determine eutectic solidification mechanisms

    International Nuclear Information System (INIS)

    Nogita, K.; Dahle, A.K.; Drennan, J.

    2002-01-01

    Full text: This study shows the application of electron backscatter diffraction (EBSD) in SEM and convergent beam electron diffraction (CBED) in FEG-TEM to determine eutectic nucleation and growth in hypoeutectic Al-Si foundry alloys. Because the eutectic reaction is often the final stage of solidification it can be expected to have a significant impact on the formation of casting defects, particularly porosity. Previous EBSD work by Nogita and Dahle (2001), Dahle et al (2001), has shown that the eutectic nucleates on the primary phase in the unmodified alloy, and eutectic grains are nucleated in the intergranular liquid, instead of filling the dendrite envelopes, when Sr or Sb is added. However, the orientation relationship between silicon and aluminium in the eutectic has so far not been determined because of difficulties with sample preparation for EBSD and also detection limitations of Kikuchi refraction of silicon and aluminium, particularly in modified alloys with a refined eutectic. The combination of the EBSD technique in SEM and CBED in TEM analyses can provide crystallographic orientation relationships between primary aluminium dendrites, eutectic aluminium and silicon, which are important to explicitly define the solidification mode of the eutectic in hypoeutectic Al-Si alloys. These relationships are influenced, and altered, by the addition of certain elements. This paper also describes the sample preparation techniques for SEM and TEM for samples with different eutectic structures. The advantages the techniques are discussed. Copyright (2002) Australian Society for Electron Microscopy Inc

  11. Sorption of radionuclides from Pb-Bi melt. Report 1

    International Nuclear Information System (INIS)

    Konovalov, Eh.E.; Il'icheva, N.S.; Trifonova, O.E.

    2015-01-01

    Results of laboratory investigations of sorption and interfacial distribution of 54 Mn, 59 Fe, 60 Co, 106 Ru, 125 Sb, 137 Cs, 144 Ce, 154,155 Eu and 235,238 U radionuclides in the system Pb-Bi melt - steel surface are analyzed. It is shown that 106 Ru and 125 Sb are concentrated in Pb-Bi melt and other radionuclides with higher oxygen affinity are sorbed on oxide deposits on structural materials. Temperature dependences of sorption efficiency of radionuclides are studied. It is shown that there is sharp increase of this value for all radionuclides near the temperature range 350-400 deg C. Recommendations are given on the use of 106 Ru and 125 Sb as a reference for fuel element rupture detection system with radiometric monitoring of coolant melt samples and 137 Cs, 134 Cs, 134m Cs with radiometric monitoring of sorbing samples [ru

  12. Effect of Pb and Cr Substitutions on Phase Formation and Excess Conductivity of Bi-2212 Superconductor

    International Nuclear Information System (INIS)

    Khir, F. L. M.; Mohamed, Z.; Yusuf, A. A.; Yusof, M. I. M.; Yahya, A. K.

    2010-01-01

    The influence of Pb and Cr substitutions on the superconducting properties of Bi 2 Sr 2 CaCu 2 O 8 (Bi-2212) superconductors is reported. The samples were prepared from Bi 2-x Pb x Sr 2 Ca 2-y Cr y Cu 3 O 10-δ (x = 0-0.3, y = 0-0.3) starting composition by the solid-state-reaction method. XRD analysis showed formation of pure Bi-2212 for (x = 0, y = 0), (x = 0.3, y = 0.2,) and (x = 0.3, y = 0.2,) starting compositions. Excess conductivity analysis based on Asmalazov-Larkin theory on single-phased Bi2212 samples showed 2D to 3D transition in superconducting fluctuation behavior (SFB) for all the samples. Highest 2D-3D transition temperature, T 2D-3D was observed at Pb and Cr substitutions of x = 0.3, and x = 0.2, respectively.

  13. Modified Welding Technique of a Hypo-Eutectic Al-Cu Alloy for Higher Mechanical Properties

    Science.gov (United States)

    Ghosh, B. R.; Gupta, R. K.; Biju, S.; Sinha, P. P.

    GTAW process is used for welding of pressure vessels made of hypo-eutectic Al-Cu alloy AA2219 containing 6.3% Cu. As welded Yield strength of the alloy was found to be in the range of 140-150 MPa, using conventional single pass GTAW technique on both AC and DCSP modes. Interestingly, it was also found that weld-strength decreased with increase in thickness of the weld coupons. Welding metallurgy of AA2219 Al alloy was critically reviewed and factors responsible for lower properties were identified. Multipass GTAW on DCSP mode was postulated to improve the weld strength of this alloy. A systematic experimentation using 12 mm thick plates was carried out and YS of 200 MPa has been achieved in the as welded condition. Thorough characterization including optical and electron microscopy was conducted to validate the metallurgical phenomena attributable to improvement in weld strength. This paper presents the conceptual understanding of welding metallurgy of AA2219 alloy and validation by experiments, which could lead to better weld properties using multipass GTAW on DCSP mode.

  14. Synthesis and application of a novel Cu/RGO@Pb alloy for lead-acid batteries

    International Nuclear Information System (INIS)

    Wu, Yumeng; Zhao, Ruirui; Zhou, Huawen; Zhang, Dejing; Zhao, Wei; Chen, Hongyu

    2016-01-01

    In this work, a novel Cu/RGO@Pb alloy was prepared successfully and tested in the simulated lead-acid battery environment. In preparing the novel alloy, Cu/RGO composite was firstly synthesized in order to increase the wettability of RGO to Pb, and then the composite was added to the molten lead to obtain the target alloy. Scanning electron microscope, energy dispersive spectrometer, X-ray diffraction as well as electrochemical measurements were employed to evaluate the performance of the obtained composite and alloy. Results show that the prepared Cu/RGO@Pb possessed higher oxygen evolution over-potential and lower hydrogen evolution over-potential than the contrast alloy, indicating this novel alloy was more suitable for using as positive grids in lead acid batteries. Moreover, the RGO additive could inhibit the formation of Pb(II) and Pb(IV) film on the surface of the alloy, which could enhance the deep-charge/discharge performance of the grids and improve the corrosion resistance.

  15. Self-annealing in a two-phase Pb-Sn alloy after processing by high-pressure torsion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Nian Xian [Materials Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom); Chinh, Nguyen Q. [Department of Materials Physics, Eötvös Loránd University, 1117 Budapest, Pázmány Péter s. 1/A. (Hungary); Kawasaki, Megumi [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Departments of Aerospace & Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453 (United States); Huang, Yi, E-mail: Y.Huang@soton.ac.uk [Materials Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom); Langdon, Terence G. [Materials Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom); Departments of Aerospace & Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453 (United States)

    2016-06-01

    A Pb-62% Sn two-phase eutectic alloy was processed by high-pressure torsion (HPT) and stored at room temperature (RT) to investigate the occurrence of self-annealing. The microstructural characteristics and mechanical properties were recorded during self-annealing using scanning electron microscopy, tensile testing and nanoindentation. Processing by HPT produces a weakening effect but storage at RT leads to a gradual increase in the hardness together with significant grain growth. Nanoindentation tests were performed by applying both the indentation depth-time (h-t) relationship at the holding stage and the hardness, H, at various loading rates in order to explore the evolution of the strain rate sensitivity (SRS), m. The results obtained by tensile testing and nanoindentation are consistent despite the large difference in the volumes of the examined regions, thereby confirming the validity of using nanoindentation to measure the strain rate sensitivity.

  16. Eutectic fusion used for the survey of transport of mass in metallic solutions

    International Nuclear Information System (INIS)

    Savane, Y.S.; Katty, S.; Balde, M.L.; Cisse, S.; Rogov, V.I.

    1997-09-01

    The phenomenon of eutectic fusion could be used for the survey of transport of mass in metallic solutions, which allows to determine the part of the ionic conductibility in the solutions. The survey done in the system In 2 Bi Bi-In at a temperature of 72 deg. C with a current of 4A allowed to find a ionic current of 2,6.10 -3 which constitutes about 0,07% of the total current. So the part of ionic conductibility in the eutectic fusion of the system In 2 Bi Bi-In is of 0,07%. (author)

  17. Comparison of electrochemical performance of as-cast Pb-1 wt.% Sn and Pb-1 wt.% Sb alloys for lead-acid battery components

    Energy Technology Data Exchange (ETDEWEB)

    Osorio, Wislei R.; Peixoto, Leandro C.; Garcia, Amauri [Department of Materials Engineering, University of Campinas - UNICAMP, PO Box 612, 13083-970 Campinas, SP (Brazil)

    2010-03-15

    A comparative experimental study of the electrochemical features of as-cast Pb-1 wt.% Sn and Pb-1 wt.% Sb alloys is carried out with a view to applications in the manufacture of lead-acid battery components. The as-cast samples are obtained using a water-cooled unidirectional solidification system. Pb-Sn and Pb-Sb alloy samples having similar coarse cell arrays are subjected to corrosion tests in order to assess the effect of Sn or Sb segregation in the cell boundary on the electrochemical performance. Electrochemical impedance spectroscopy (EIS) diagrams, potentiodynamic polarization curves and an equivalent circuit analysis are used to evaluate the electrochemical parameters in a 0.5 M H{sub 2}SO{sub 4} solution at 25 C. Both the experimental and simulated EIS parameters evidence different kinetics of corrosion. The Pb-1 wt.% Sn alloy is found to have a current density which is of about three times lower than that of the Pb-1 wt.% Sb alloy which indicates that dilute Pb-Sn alloys have higher potential for application as positive grid material in maintenance-free Pb-acid batteries. (author)

  18. Investigation of enthalpy and specific heat of the gallium-indium-tin eutectic alloy

    International Nuclear Information System (INIS)

    Roshchupkin, V.V.; Migaj, L.L.; Fordeeva, L.K.; Perlova, N.L.

    1978-01-01

    Enthalpy and specific heat of the fusible (melting point is 10.6 deg C) eutectic alloy (67% Ga - 20.5% In - 12.5% Sn according to mass) are determined by the mixing method. The determination was carried out in vacuum at the residual pressure of >= 1x10 -5 torr in the temperature range from 59.3 to 437.0 deg C. It is established that temperature dependence of alloy enthalpy is described by the equation: Hsub(t) - Hsub(0degC)=1.014+0.0879t-0.0000129 t 2 , where (Hsub(t) - Hsub(0degC)) is enthalpy, cal/g; t-temperature, deg C. Mean-square dispersion is +-0.6%. Temperature dependence of alloy specific heat in the temperature range under study was determined by differentiation of the equation obtained for enthalpy: Csub(p)=0.0879-0.000026t, where Csub(p)-specific heat, cal/gx deg. It is supposed that temperature increase makes it possible to decrease slightly specific heat

  19. Thermal expansion properties of Bi-2212 in Ag or an Ag-alloy matrix

    International Nuclear Information System (INIS)

    Tenbrink, J.; Krauth, H.

    1994-01-01

    The thermal expansion properties of polycrystalline Bi 2 Sr 2 Ca 1 Cu 2 O 8+x melt-processed bulk specimens, and Bi 2 Sr 2 Ca 1 Cu 2 O 8+x monocore as well as multifilamentary round wires in Ag or Ag-alloy matrix have been investigated over the temperature range from -150 to 800 degrees C. Although the thermal expansion of Bi 2 Sr 2 Ca 1 Cu 2 O 8+x is distinctly lower compared with Ag, the thermal expansion properties of the Bi 2 Sr 2 Ca 1 Cu 2 O 8+x -Ag or AgNiMg-alloy composite conductors are essentially governed by the matrix material. The thermal expansion of the encountered oxide-dispersion-strengthened AgNiMg alloys is only slightly lower compared with that of pure Ag. Therefore the thermal expansion of all investigated Bi 2 Sr 2 Ca 1 Cu 2 O 8+x -Ag or Ag-alloy composite wires was found to be close to that of pure Ag. The reason for this striking behaviour is shown to be related to a surprisingly low elastic modulus of the polycrystalline Bi-2212 wire cores of the order of 10 to a maximum 40 GPa. (author)

  20. Corrosion behavior of as-cast binary Mg-Bi alloys in Hank's solution

    Directory of Open Access Journals (Sweden)

    Wei-li Cheng

    2015-11-01

    Full Text Available Biodegradable Mg-xBi (x = 3, 6 and 9wt.% alloys were fabricated by ingot casting, and the change of corrosion behavior of the alloys in the Hank's solution was analyzed with respect to the microstructure using optical micrograph (OM, X-ray diffraction (XRD, scanning electron microscope (SEM equipped with an energy dispersive X-ray spectrometer (EDS, electrochemical and immersion tests. The results show that the microstructures of the as-cast Mg-Bi alloys mainly consisted of dendritic ?Mg grains and Mg3Bi2 phase in common, with the secondary dendrite arm spacing (SDAS decreasing significantly from 41.2 靘 to 25.4 靘 and the fraction of Mg3Bi2 increasing from 3.1% to 10.7%. Furthermore, the corrosion rate increasing from 1.32 mm昦-1 to 8.07 mm昦-1 as the Bi content was increased from 3wt.% to 9wt.%. The reduced corrosion resistance was mainly ascribed to the increasing fraction of the second phase particles, which bring positive effects on the development of pitting.

  1. Comparative study of silicate glasses containing Bi2O3, PbO and BaO: Radiation shielding and optical properties

    International Nuclear Information System (INIS)

    Kirdsiri, K.; Kaewkhao, J.; Chanthima, N.; Limsuwan, P.

    2011-01-01

    Research highlights: → We change Bi 2 O 3 , PbO and BaO concentration in silicate glasses. → The densities of Bi 2 O 3 glasses more than PbO glasses and BaO glasses. → The Um of Bi 2 O 3 glasses and PbO glasses are comparable and more than BaO glasses. → This suggests that Bi 2 O 3 can replace PbO in radiation shielding glasses. - Abstract: The radiation shielding and optical properties of xBi 2 O 3 :(100-x)SiO 2 , xPbO:(100-x)SiO 2 and xBaO:(100-x)SiO 2 glass systems (where 30 ≤ x ≤ 70 is the composition by weight%) have been investigated. Total mass attenuation coefficients (μ m ) of glasses at 662 keV were improved by increasing their Bi 2 O 3 and PbO content, which raised the photoelectric absorption in glass matrices. Raising the BaO content to the same fraction range, however, brought no significant change to μ m . These results indicate that photon is strongly attenuated in Bi 2 O 3 and PbO containing glasses, and but not in BaO containing glass. The results from the optical absorption spectra show an edge that was not sharply defined; clearly indicating the amorphous nature of glass samples. It is observed that the cutoff wavelength for Bi 2 O 3 containing glass was longer than PbO and BaO containing glasses.

  2. Synthesis and melting behaviour of Bi, Sn and Sn–Bi nanostructured alloy

    Energy Technology Data Exchange (ETDEWEB)

    Frongia, F.; Pilloni, M.; Scano, A.; Ardu, A.; Cannas, C.; Musinu, A. [Università di Cagliari, Dipartimento di Scienze Chimiche e Geologiche and Cagliari Research Unit of the National Consortium of Materials Science and Technology (INSTM), Cittadella Universitaria di Monserrato, 09042 Monserrato, CA (Italy); Borzone, G.; Delsante, S. [Department of Chemistry and Industrial Chemistry, Genoa University and Genoa Research Unit of the National Consortium of Materials Science and Technology (INSTM), Via Dodecaneso 31, I-16146 Genoa (Italy); Novakovic, R. [National Research Council (CNR), Institute for Energetics and Interphases (IENI), Via De Marini 6, 16149 Genoa (Italy); Ennas, G., E-mail: ennas@unica.it [Università di Cagliari, Dipartimento di Scienze Chimiche e Geologiche and Cagliari Research Unit of the National Consortium of Materials Science and Technology (INSTM), Cittadella Universitaria di Monserrato, 09042 Monserrato, CA (Italy)

    2015-02-25

    Highlights: • Aqueous solution route is used to produce Bi, Sn and Bi–Sn nanoparticles. • HRTEM revealed core–shell and Janus type structures of Bi–Sn nanoparticles. • Melting temperature depression of Bi and Bi–Sn nanoparticles were measured by DSC. • DSC data on Bi melting temperature depression agrees with theoretical values. - Abstract: Lead-free solders based on Bi–Sn bimetallic nanoclusters with eutectic composition (Bi{sub 43}Sn{sub 57}) were synthesized at low temperature by simultaneous reduction reaction from aqueous solution containing bismuth and tin chlorides, using potassium borohydride as a reducing agent. By the same processing route, pure bismuth and tin nanoparticles have also been prepared. Microstructure, morphology and composition of the samples were characterized by X-ray powder diffraction (XRD), transmission (TEM) and scanning electron microscopy (SEM). TEM images of Bi–Sn nanoparticles show average size ranging from 30 to 100 nm. Thermal behaviour of Bi–Sn nanopowders was studied by DSC (differential scanning calorimetry) and a melting temperature (135 °C) lower than that of the corresponding microcrystalline sample (139 °C) was observed. SEM micrographs of the thermally treated sample up to 400 °C show fine spherical grains in the micrometer range with finer powder particles on the surface. XRD powder diffraction analysis indicates the formation of bismuth and tin nanophases with an average particle size of 85 and 126 nm, respectively. The oxidation behaviour of the samples was also investigated. The results obtained have been analyzed in view of theoretical models describing the melting temperature depression of nanoparticles.

  3. Identification of intermetallic phases in a eutectic Al-Si casting alloy using electron backscatter diffraction pattern analysis

    International Nuclear Information System (INIS)

    Kral, M.V.; McIntyre, H.R.; Smillie, M.J.

    2004-01-01

    Intermetallic phases in sand cast eutectic Al-Si alloys were characterized using a combination of SEM, EDS and EBSD pattern analysis. Chinese script α-phase particles were consistent with cubic Al 19 (Fe,Mn) 5 Si 2 . Plate-shaped β-phase particles were consistent with tetragonal Al 3 (Fe,Mn)Si 2

  4. Handbook on lead-bismuth eutectic alloy and lead properties, materials compatibility, thermal-hydraulics and technologies

    International Nuclear Information System (INIS)

    2007-01-01

    As part of the development of advanced nuclear systems, including accelerator-driven systems (ADS) proposed for high-level radioactive waste transmutation and generation IV reactors, heavy liquid metals such as lead (Pb) or lead-bismuth eutectic (LBE) are under evaluation as reactor core coolant and ADS neutron target material. Heavy liquid metals are also being envisaged as target materials for high-power neutron spallation sources. The objective of this handbook is to collate and publish properties and experimental results on Pb and LBE in a consistent format in order to provide designers with a single source of qualified properties and data and to guide subsequent development efforts. The handbook covers liquid Pb and LBE properties, materials compatibility and testing issues, key aspects of the thermal-hydraulics and system technologies, existing test facilities, open issues and perspectives. (author)

  5. Mechanical properties of Bi-In-Zn/ Cu solder joint system

    International Nuclear Information System (INIS)

    Ervina Efzan Mohd Noor; Mohammed Noori Ridha; Ahmad Badri Ismail; Nurulakmal Mohd Sharif; Kuan Yew Cheong; Tadashi Ariga; Zuhailawati Hussain

    2009-01-01

    Full text: In recent years, the pollution of environment from lead (Pb) and Pb-containing compounds in microelectronic devices attracts more and more attentions in academia and industry; the lead-free solder alloys begin to replace the lead-based solders in packaging process of some devices and components. In this works, microstructure and mechanical properties of different reflow temperature (80, 100, 120 and 140 degree Celsius) for solder joints on shear strength of Bi-In-Zn lead free solder with low melting temperature of 60 degree Celsius on Cu solder joint has been investigated. This paper will compared the mechanical properties of the Bi-In-Zn lead-free solder alloys with current lead-free solder, Sn-Ag-Cu solder alloy. The fracture surface analyses have been observed by Optical Microscope and were investigated by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray (EDX) and proved it by X-ray diffraction (XRD). (author)

  6. Frozen magnetoresistance at magnetization reversal of granular Bi(Pb)-HTSC

    International Nuclear Information System (INIS)

    Sukhanov, A.A.; Omelchenko, V.I.

    2004-01-01

    The frozen magnetoresistance dependences of granular Bi(Pb)-HTSC samples on fields initiating a magnetic flux trapping and on magnetic reversal fields Rt(Hi, Hr) are investigated. It is found that the Rt (Hr) dependences are nonmonotonous. The frozen magnetoresistance decreases substantially after the first pulse Hr applied (Hr < Hi) but remains practically unchanged at subsequent remagnetization by magnetic pulses of alternating polarity and of the same amplitude. The effect of magnetic reversal on magnetoresistance anisotropy and the negative magnetoresistance phenomenon are studied. Is shown that the results obtained are inconsistent with the model of critical state for SC grains and the model of SC loops but are well described quantitatively by the proposed Bi(Pb)-HTSC model according to which the magnetic flux trapping occurs in normal grains with HTSC shells and the sample resistance is determined by weak link chains

  7. Monotectic four-phase reaction in Al-Bi-Zn alloys

    Energy Technology Data Exchange (ETDEWEB)

    Groebner, J. [Clausthal University of Technology, Institute of Metallurgy, Robert-Koch-Str. 42, D-38678 Clausthal-Zellerfeld (Germany); Mirkovic, D. [Clausthal University of Technology, Institute of Metallurgy, Robert-Koch-Str. 42, D-38678 Clausthal-Zellerfeld (Germany); Schmid-Fetzer, R. [Clausthal University of Technology, Institute of Metallurgy, Robert-Koch-Str. 42, D-38678 Clausthal-Zellerfeld (Germany)]. E-mail: schmid-fetzer@tu-clausthal.de

    2005-06-15

    Thermodynamic phase diagram calculations were used for the systematic search for a monotectic four-phase reaction in ternary Al-alloys. Systems with intermetallic phases and also the elements Cd and Hg were excluded in the present search. The ternary Al-Bi-Zn is a rare occasion where such a reaction, L' = L' + (Al)' + (Zn), actually occurs. Experimental work could be focused on key samples in that system and involved DSC for thermal analysis and calorimetry, and also metallographic analysis using SEM/EDX. Experimental results verify the existence of the monotectic reaction and were also used for a quantitative thermodynamic modeling of Al-Bi-Zn. Solidification paths and microstructures of Al-Bi-Zn alloys are shown to be rather complex. Using thermodynamic calculations, these rich details involving up to three invariant reactions and unexpected monovariant reaction types can be clearly revealed and understood.

  8. Coatings for directional eutectics

    Science.gov (United States)

    Rairden, J. R.; Jackson, M. R.

    1976-01-01

    Coatings developed to provide oxidation protection for the directionally-solidified eutectic alloy NiTaC-B (4.4 weight percent Cr) were evaluated. Of seven Co-, Fe- and Ni-base coatings that were initially investigated, best resistance to cyclic oxidation was demonstrated by duplex coatings fabricated by depositing a layer of NiCrAl(Y) by vacuum evaporation from an electron beam source followed by deposition of an Al overlayer using the pack cementation process. It was found that addition of carbon to the coating alloy substantially eliminated the problem of fiber denudation in TaC-type eutectic alloys. Burner rig cycled NiTaC-B samples coated with Ni-20Cr-5Al-0.1C-0.1Y+Al and rupture-tested at 1100 deg C performed as well as or better than uncoated, vacuum cycled and air-tested NiTaC-13; however, a slight degradation with respect to uncoated material was noted in air-stress rupture tests at 870 deg C for both cycled and uncycled samples.

  9. Design and calculation of tritium extraction from liquid LiPb by bubble columns for ITER

    International Nuclear Information System (INIS)

    Xie, Bo

    2009-04-01

    A mathematical model describing the complex fluid-dynamics of a bubble extractor from liquid LiPb loop for ITER is presented. A parametric analysis of the extraction efficiency of a bubble column as a function of the process parameters is carried out and the design of a bubble extractor system is proposed. On this base, a mathematical model is built by taking into consideration the kinetics of deuterium desorption from liquid LiPb alloy. The calculation data of deuterium release-behavior from liquid LiPb under different operating conditions of temperature and deuterium partial pressures and helium gas flow-rates in the liquid LiPb alloy are obtained. These results have shown that the overall re- lease process is governed by the diffusion of deuterium atoms in the LiPb and by the heterogeneous reaction at the gas-eutectic interface of the deuterium atoms recombination under the probable working temperature range. (authors)

  10. Potential containment materials for liquid-lead and lead-bismuth eutectic spallation neutron source

    International Nuclear Information System (INIS)

    Park, J.J.; Butt, D.P.; Beard, C.A.

    1997-11-01

    Lead (Pb) and lead-bismuth eutectic (44Pb-56Bi) have been the two primary candidate liquid-metal target materials for the production of spallation neutrons. Selection of a container material for the liquid-metal target will greatly affect the lifetime and safety of the target subsystem. For the lead target, niobium-1 (wt%) zirconium (Nb-1Zr) is a candidate containment material for liquid lead, but its poor oxidation resistance has been a major concern. The oxidation rate of Nb-1Zr was studied based on the calculations of thickness loss due to oxidation. According to these calculations, it appeared that uncoated Nb-1Zr may be used for a one-year operation at 900 C at P O 2 = 1 x 10 -6 torr, but the same material may not be used in argon with 5-ppm oxygen. Coating technologies to reduce the oxidation of Nb-1Zr are reviewed, as are other candidate refractory metals such as molybdenum, tantalum, and tungsten. For the Pb-Bi target, three candidate containment materials are suggested based on a literature survey of the materials compatibility and proton irradiation tests: Croloy 2-1/4, modified 9Cr-1Mo, and 12Cr-1Mo (HT-9) steel. These materials seem to be used only if the lead-bismuth is thoroughly deoxidized and treated with zirconium and magnesium

  11. 1D chain formation by coadsorption of Pb and Bi on Cu(001): Determination using low energy electron diffraction

    Science.gov (United States)

    Kabiruzzaman, Md; Ahmed, Rezwan; Nakagawa, Takeshi; Mizuno, Seigi

    2017-10-01

    Coadsorption of two heavy metals, Pb and Bi, on Cu(001) at room temperature has been studied using low energy electron diffraction (LEED). c(4 × 4), c(2 × 2), and c(9√{ 2}×√{ 2}) phases are obtained at different coverages; here, we have determined the best-fit structure of c(4 × 4) phase. This structure can be described as a 1D substitutional chain arrangement of Pb and Bi atoms between the Cu rows along the [110] direction. The unit cell in the two-dimensional (2D) surface consists of one Bi atom, two Pb atoms, and four Cu atoms with one vacancy at the center. The optimal structure parameters demonstrate that Bi atoms are located at fourfold-hollow sites and that Pb atoms are laterally displaced by 0.78 Å from the fourfold-hollow site toward the vacancy. The reasons for the formation of the c(4 × 4) structure upon deposition of Pb and Bi on Cu(001) are discussed in comparison with a similar structure formed by the individual adsorption of Pb on the same substrate.

  12. Microstructure and mechanical properties of an extruded Mg-8Bi-1Al-1Zn (wt%) alloy

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Shuaiju [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Yu, Hui, E-mail: yuhuidavid@gmail.com [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Materials Commercialization Center, Korea Institute of Materials Science, Changwon 51508 (Korea, Republic of); Zhang, Huixing [Mechanical and Material School, Tianjin Sino-German University of Applied Sciences, Tianjin 300350 (China); Cui, Hongwei [School of Materials Science and Engineering, Shangdong University of Technology, Zibo 255049 (China); Park, Sung Hyuk [School of Materials Science and Engineering, Kyungpook National University, Daegu 702701 (Korea, Republic of); Zhao, Weiming [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); You, Bong Sun [Materials Commercialization Center, Korea Institute of Materials Science, Changwon 51508 (Korea, Republic of)

    2017-04-06

    In this study, the microstructural evolution and mechanical properties of a newly developed rare earth free Mg-8Bi-1Al-1Zn (BAZ811, in wt%) alloy were investigated and compared with those of a commercial AZ31 alloy. The as-extruded BAZ811 alloy with much finer grain size shows more homogeneous dynamical recrystallized (DRXed) microstructure and weaker basal texture than those of AZ31 alloy. In addition, compared with bimodal structure AZ31 alloy containing only relatively coarse and sparse Al{sub 8}Mn{sub 5} phases, the coexistence of strip-like fragmented Mg{sub 3}Bi{sub 2} precipitate and nano-size Mg{sub 3}Bi{sub 2} particles in the microstructure was observed in BAZ811 alloy. Moreover, the BAZ811 alloy exhibits a tensile yield stress of 291 MPa, an ultimate tensile strength of 331 MPa, an elongation to failure of 14.6% as well as a reduction in yield asymmetry, which is mainly attributed to the combined effects of grain refinement and micro-scale broken Mg{sub 3}Bi{sub 2} particles together with nano-scale spherical Mg{sub 3}Bi{sub 2} precipitates. The strain hardening behavior of both BAZ811 and AZ31 alloys were also discussed in terms of microstructure variation.

  13. A note on structural and dielectric properties of BiFeO3- PbTiO3 and BiFeO3- PbZrO3 composites

    International Nuclear Information System (INIS)

    Satpathy, S. K.; Mohanty, N. K.; Behera, A. K.; Behera, B.; Nayak, P.

    2015-01-01

    The composites of BiFeO 3 -PbTiO 3 (BF-PT) and BiFeO 3 -PbZrO 3 (BF-PZ) were prepared by mixed oxide method. Room temperature X-ray diffraction data confirms the rhombohedral and tetragonal crystal structure respectively. Dielectric constant of BF-PZ is found to give high value compared to BF-PT and hence, there is an increase value of ac conductivity for the former. Both the composites show negative temperature coefficient of resistance (NTCR) behavior. The activation energies of BF-PT and BF-PZ are found to be 0.35 eV and 0.53 eV respectively. The d 33 coefficients are found to be 2.0 and 2.1 pC/N for BF-PT and BF-PZ respectively

  14. Liquidus surface of the triple reciprocal system PbTe+CdS↔PbS+CdTe

    International Nuclear Information System (INIS)

    Tomashik, Z.F.; Tomashik, V.N.

    1987-01-01

    Using differential-thermal and microstructural analyses and mathematical design interaction in PbTe-CdS system is studied. Liquidus surface of the triple reciprocal system PbTe+CdS↔PbS+CdTe is plotted. It is shown that PbTe-CdS system phase diagram is of eutectic type. Maximal solubility of CdS in PbTe attains 13 mol%, and of PbTe in CdS is not over 1 mol%. Projection of liquidus surface of the PbTe+CdS↔PbS+CdTe triple reciprocal system consists of two primary crystallization fields: CdTe x S 1-x and PbTe x S 1-x solid solutions separated by eutectic line

  15. High dielectric permittivity in the microwave region of SrBi2Nb2O9 (SBN) added La2O3, PbO and Bi2O3, obtained by mechanical alloying

    Science.gov (United States)

    Rocha, M. J. S.; Silva, P. M. O.; Theophilo, K. R. B.; Sancho, E. O.; Paula, P. V. L.; Silva, M. A. S.; Honorato, S. B.; Sombra, A. S. B.

    2012-08-01

    This paper presents the microwave dielectric properties and a structural study of SrBi2Nb2O9 (SBN) added La2O3, PbO or Bi2O3 obtained by a solid state procedure. High-energy mechanical milling was used to reduce the particle size, which allows for a better shaping of the green body and an increased reactivity. The mechanical milling activation process produced a reduced sintering temperature in the material, decreasing the loss of the volatile elements and controlling the growth of the grain that is produced when a high temperature is required to obtain dense ceramics. The incorporation of La3+, or Pb2+, or Bi3+ of different amounts (0, 3, 5, 10 and 15 wt%) was used to improve the densification without changing the crystal structure, since with a low doping content these ions can occupy the A site of the perovskite blocks; they can also occupy the Bi3+ sites in Bi2O3 layers. A single orthorhombic phase was formed after calcination at 800 °C for 2 h. X-ray diffraction, Fourier transformation, infrared and Raman spectroscopy have been carried out in order to investigate the effects of doping on SBN. The dielectric permittivity (ɛ‧r) and loss in the microwave region (2-4 GHz) of SBN ceramics with additions of Bi2O3, La2O3 and PbO were studied. Higher values of permittivity (ɛr‧ = 154.6) have been obtained for the SBN added La (15 wt%) a lower loss (tg δ = 0.01531) was also achieved in the SBN added La (15 wt%) sample with PVA and TEOS, respectively. The samples that showed the highest dielectric permittivities were all lanthanum doped, all with values of permittivity above 90. A comparative study associated with different types of binders was completed (with glycerin, PVA and TEOS). This procedure allowed us to obtain phases at lower temperatures than usually appear in the literature. The microwave dielectric properties (permittivity and loss) in the region 2-4 GHz, were studied for all samples. The structural and microwave dielectric properties of SBN show a

  16. Tensile behaviour at room and high temperatures of novel metal matrix composites based on hyper eutectic Al-Si alloys

    International Nuclear Information System (INIS)

    Valer, J.; Rodriguez, J.M.; Urcola, J.J.

    1997-01-01

    This work shows the improvement obtained on tensile stress at room and high temperatures of hyper eutectic Al-Si alloys. These alloys are produced by a combination of spray-forming, extrusion and thixoforming process, in comparison with conventional casting alloys.Al-25% Si-5%Cu. Al-25%Si-5%Cu-2%Mg and Al-30%Si-5%Cu alloys have been studied relating their microstructural parameters with tensile stress obtained and comparing them with conventional Al-20%Si. Al-36%Si and Al-50%Si alloys. Al-25%Si-5%Cu alloy-was tested before and after semi-solid forming, in order to distinguish the different behaviour of this alloy due to the different microstructure. The properties obtained with these alloys were also related to Al-SiC composites formed by similar processes. (Author) 20 refs

  17. Density functional theory study of the interfacial properties of Ni/Ni3Si eutectic alloy

    International Nuclear Information System (INIS)

    Zhao, Yuhong; Wen, Zhiqin; Hou, Hua; Guo, Wei; Han, Peide

    2014-01-01

    In order to clarify the heterogeneous nucleation potential of α-Ni grains on Ni 3 Si particles in Ni-Ni 3 Si eutectic alloy, the work of adhesion (W ad ), fracture toughness (G), interfacial energy (γ i ), and electronic structure of the index (0 0 1), (1 1 0) and (1 1 1) Ni/Ni 3 Si interfaces with two different cohesive manners are investigated using first-principles method based on density functional theory. Results indicate that the center site stacking sequence (OM) is preferable to continue the natural stacking sequence of bulk Ni and Ni 3 Si. Since OM stacking interfaces have larger W ad , G and γ i than that of the top site stacking (OT) interfaces. The Ni/Ni 3 Si (1 1 0) interface with OM stacking has the best mechanical properties. Therefore, the formation of this interface can improve the stability, ductility and fracture toughness of Ni-Ni 3 Si eutectic alloy. The calculated interfacial energy of Ni/Ni 3 Si (0 0 1), (1 1 0) and (1 1 1) interfaces with OM stacking proves the excellent nucleation potency of Ni 3 Si particles for α-Ni phase from thermodynamic considerations. Besides, the electronic structure and chemical bonding of (1 1 0) interface with OM stacking are also discussed.

  18. A eutectic-alloy-infused soft actuator with sensing, tunable degrees of freedom, and stiffness properties

    Science.gov (United States)

    Hao, Yufei; Wang, Tianmiao; Xie, Zhexin; Sun, Wenguang; Liu, Zemin; Fang, Xi; Yang, Minxuan; Wen, Li

    2018-02-01

    This paper presents a soft actuator embedded with two types of eutectic alloys which enable sensing, tunable mechanical degrees of freedom (DOF), and variable stiffness properties. To modulate the stiffness of the actuator, we embedded a low melting point alloy (LMPA) in the bottom portion of the soft actuator. Different sections of the LMPA could be selectively melted by the Ni-Cr wires twined underneath. To acquire the curvature information, EGaIn (eutectic gallium indium) was infused into a microchannel surrounding the chambers of the soft actuator. Systematic experiments were performed to characterize the stiffness, tunable DOF, and sensing the bending curvature. We found that the average bending force and elasticity modulus could be increased about 35 and 4000 times, respectively, with the LMPA in a solid state. The entire LMPA could be melted from a solid to a liquid state within 12 s. In particular, up to six different motion patterns could be achieved under each pneumatic pressure of the soft actuator. Furthermore, the kinematics of the actuator under different motion patterns could be obtained by a mathematical model whose input was provided by the EGaIn sensor. For demonstration purposes, a two-fingered gripper was fabricated to grasp various objects by adjusting the DOF and mechanical stiffness.

  19. Electrodeposition of Zn and Cu–Zn alloy from ZnO/CuO precursors in deep eutectic solvent

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Xueliang [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Zou, Xingli, E-mail: xinglizou@shu.edu.cn [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Lu, Xionggang, E-mail: luxg@shu.edu.cn [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Lu, Changyuan; Cheng, Hongwei; Xu, Qian [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Zhou, Zhongfu [State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Institute of Mathematics and Physics, Aberystwyth University, Aberystwyth SY23 3BZ (United Kingdom)

    2016-11-01

    Graphical abstract: Micro/nanostructured Zn and Cu–Zn alloy films have been electrodeposited directly from ZnO/CuO precursors in ChCl/urea-based DES, the typical nucleation-growth mechanism and the micro/nanostructures-formation process are determined. Display Omitted - Highlights: • Micro/nanostructured Zn films have been electrodeposited directly from ZnO precursor in deep eutectic solvent (DES). • The morphology of the Zn electrodeposits depends on the cathodic potential and temperature. • The electrodeposited Zn films exhibit homogeneous morphologies with controllable particle sizes and improved corrosion resistance. • Cu–Zn alloy films have also been electrodeposited directly from their metal oxides precursors in DES. - Abstract: The electrodeposition of Zn and Cu–Zn alloy has been investigated in choline chloride (ChCl)/urea (1:2 molar ratio) based deep eutectic solvent (DES). Cyclic voltammetry study demonstrates that the reduction of Zn(II) to Zn is a diffusion-controlled quasi-reversible, one-step, two electrons transfer process. Chronoamperometric investigation indicates that the electrodeposition of Zn on a Cu electrode typically involves three-dimensional instantaneous nucleation with diffusion-controlled growth process. Micro/nanostructured Zn films can be obtained by controlling the electrodeposition potential and temperature. The electrodeposited Zn crystals preferentially orient parallel to the (101) plane. The Zn films electrodeposited under more positive potentials and low temperatures exhibit improved corrosion resistance in 3 wt% NaCl solution. In addition, Cu–Zn alloy films have also been electrodeposited directly from CuO–ZnO precursors in ChCl/urea-based DES. The XRD analysis indicates that the phase composition of the electrodeposited Cu–Zn alloy depends on the electrodeposition potential.

  20. Pb5Bi24Se41: A new member of the homologous series forming topological insulator heterostructures

    International Nuclear Information System (INIS)

    Segawa, Kouji; Taskin, A.A.; Ando, Yoichi

    2015-01-01

    We have synthesized Pb 5 Bi 24 Se 41 , which is a new member of the (PbSe) 5 (Bi 2 Se 3 ) 3m homologous series with m=4. This series of compounds consist of alternating layers of the topological insulator Bi 2 Se 3 and the ordinary insulator PbSe. Such a naturally-formed heterostructure has recently been elucidated to give rise to peculiar quasi-two-dimensional topological states throughout the bulk, and the discovery of Pb 5 Bi 24 Se 41 expands the tunability of the topological states in this interesting homologous series. The trend in the resistivity anisotropy in this homologous series suggests an important role of hybridization of the topological states in the out-of-plane transport. - Graphical abstract: X-ray diffraction profiles taken on cleaved surfaces of single-crystal samples of the (PbSe) 5 (Bi 2 Se 3 ) 3m homologous series with various m values up to 4, which realizes topological insulator heterostructures. Schematic crystal structure of the new phase, m=4, is also shown. - Highlights: • We have synthesized a new member of the homologous series related to topological insulators. • In this compound, a heterostructure of topological and ordinary insulators naturally forms. • Resistivity anisotropy suggests an important role of hybridization of the topological states. • This compound expands the tunability of the topological states via chemical means

  1. A vanadium alloy for the application in a liquid metal blanket of a fusion reactor

    Science.gov (United States)

    Borgstedt, H. U.; Grundmann, M.; Konys, J.; Perić, Z.

    1988-07-01

    The vanadium alloy V3Ti1Si has been corrosion tested in liquid lithium and the eutectic alloy Pb-17Li at 550°C. This alloy has a comparable corrosion resistance to the alloy V15Cr5Ti in lithium. In this molten metal it is superior to stainless steel AISI 316. In the Pb-17Li melt it is even superior to martensitic steels. The alloy has only a weak tendency to be dissolved. It is sensitive to an exchange of non-metallic elements, which causes the formation of a hardened surface layer. These chemical effects are influenced by the mass and surface ratios of the vanadium alloy to the molten metals and other structural materials. These ratios are unfavorable in the two test loops. The effects might be less pronounced in a vanadium alloy/liquid metal fusion reactor blanket.

  2. Thermodynamic properties of the liquid Bi-Cu-Sn lead-free solder alloys

    Directory of Open Access Journals (Sweden)

    Kopyto M.

    2009-01-01

    Full Text Available The electromotive force measurement method was employed to determine the thermodynamic properties of liquid Bi-Cu-Sn alloys using solid electrolyte galvanic cells as shown below: Kanthal+Re, Bi-Cu-Sn, SnO2 | Yttria Stabilized Zirconia | air, Pt, Po2=0.2:1 atm Measurements were carried out for three cross-sections with constant Bi/Cu ratio equal to: 1/3, 1 and 3 and for various tin content varying every 10%, resulting in a total of 26 different alloy compositions. The temperature of the measurements varied within the range from 973 to 1325 K. A linear dependence of the e.m.f. on temperature was observed for all alloy compositions and the appropriate line equations were derived. Tin activities were calculated as function of composition and temperature. Results were presented in tables and figures.

  3. Examination of Clustering in Eutectic Microstrcture

    Directory of Open Access Journals (Sweden)

    Bortnyik K.

    2017-06-01

    Full Text Available The eutectic microstructures are complex microstructures and a hard work to describe it with few numbers. The eutectics builds up eutectic cells. In the cells the phases are clustered. With the development of big databases the data mining also develops, and produces a lot of method to handling the large datasets, and earns information from the sets. One typical method is the clustering, which finds the groups in the datasets. In this article a partitioning and a hierarchical clustering is applied to eutectic structures to find the clusters. In the case of AlMn alloy the K-means algorithm work well, and find the eutectic cells. In the case of ductile cast iron the hierarchical clustering works better. With the combination of the partitioning and hierarchical clustering with the image transformation, an effective method is developed for clustering the objects in the microstructures.

  4. Precise measurement of the densities of liquid Bi, Sn, Pb and Sb

    International Nuclear Information System (INIS)

    Wang Lianwen; Wang Qiang; Xian Aiping; Lu Kunquan

    2003-01-01

    The densities of liquid Bi, Sn, Pb and Sb have been precisely measured from the melting point up to about 1100 K using an improved Archimedean method. The densities at the melting point for liquid Bi, Sn, Pb and Sb are 10.042 x 10 3 , 6.983 x 10 3 , 10.635 x 10 3 and 6.454 x 10 3 kg m -3 , respectively. Comparisons between our data and those from the literature have been made and they show the present results to be more reliable. Rather than a linear fit for the temperature dependence of the density, a slight deviation from linearity in the temperature dependence of the densities has been observed

  5. Half-metallic antiferromagnetism in double perovskite BiPbCrCuO6

    International Nuclear Information System (INIS)

    Weng, Ke-Chuan; Wang, Y. K.

    2015-01-01

    The electronic structure and magnetic properties of BiPbCrCuO 6 double perovskite are investigated based on first-principles density functional calculations with generalized gradient approximation (GGA) and GGA incorporated with Coulomb correlation interaction U (GGA + U). The results suggest the half-metallic (HM) and antiferromagnetic (AFM) properties of BiPbCrCuO 6 double perovskite. The HM-AFM property of the double perovskite is caused by the double-exchange mechanism between neighboring Cr 5+ (t 2g 1 ↓) and Cu 2+ (t 2g 3 ↑t 2g 3 ↓e g 2 ↑e g ↓) via the intermediate O 2− (2s 2 2p 6 ) ion

  6. Influence of pressure on the solid state phase transformation of Cu–Al–Bi alloy

    International Nuclear Information System (INIS)

    Gong, Li; Jian-Hua, Liu; Wen-Kui, Wang; Ri-Ping, Liu

    2010-01-01

    The solid state phase transformation of Cu-Al-Bi alloy under high pressure was investigated by x-ray diffraction, energy dispersive spectroscopy and transmission electron microscopy. Experimental results show that the initial crystalline phase in the Cu-Al-Bi alloy annealed at 750 °C under the pressures in the range of 0–6 GPa is α-Cu solid solution (named as α-Cu phase below), and high pressure has a great influence on the crystallisation process of the Cu-Al-Bi alloy. The grain size of the α-Cu phase decreases with increasing pressure as the pressure is below about 3 GPa, and then increases (P > 3 GPa). The mechanism for the effects of high pressure on the crystallisation process of the alloy has been discussed. (condensed matter: structure, thermal and mechanical properties)

  7. Microstructural origins of high strength and high ductility in an AlCoCrFeNi2.1 eutectic high-entropy alloy

    International Nuclear Information System (INIS)

    Gao, Xuzhou; Lu, Yiping; Zhang, Bo; Liang, Ningning; Wu, Guanzhong; Sha, Gang; Liu, Jizi; Zhao, Yonghao

    2017-01-01

    Recent studies indicate that eutectic high-entropy alloys can simultaneously possess high strength and high ductility, which have potential applications in industrial fields. Nevertheless, microstructural origins of the excellent strength–ductility combination remain unclear. In this study, an AlCoCrFeNi 2.1 eutectic high-entropy alloy was prepared with face-centered cubic (FCC)(L1 2 )/body-centered-cubic (BCC)(B2) modulated lamellar structures and a remarkable combination of ultimate tensile strength (1351 MPa) and ductility (15.4%) using the classical casting technique. Post-deformation transmission electron microscopy revealed that the FCC(L1 2 ) phase was deformed in a matter of planar dislocation slip, with a slip system of {111} <110>, and stacking faults due to low stacking fault energy. Due to extreme solute drag, high densities of dislocations are distributed homogeneously at {111} slip plane. In the BCC(B2) phase, some dislocations exist on two {110} slip bands. The atom probe tomography analysis revealed a high density of Cr-enriched nano-precipitates, which strengthened the BCC(B2) phase by Orowan mechanisms. Fracture surface observation revealed a ductile fracture in the FCC(L1 2 ) phase and a brittle-like fracture in the BCC(B2) lamella. The underlying mechanism for the high strength and high ductility of AlCoCrFeNi 2.1 eutectic high-entropy alloy was finally analyzed based on the coupling between the ductile FCC(L1 2 ) and brittle BCC(B2) phases.

  8. Magnetic and structural properties of Bi(2223doped by pb and Sb

    Directory of Open Access Journals (Sweden)

    H. Salamati

    1998-04-01

    Full Text Available   In a systematic approach, we have investigated the effect of the presence of Pb and Sb in the Bi site in a BSCCO (2223 phase superconductor. There are some contradictory reports in substitution of Sb in the Bi site. Some researchers report an increase in the Tc of these materials. So, we have made an accurate stoichiometry of these superconductors and selected extra pure starting materials with appropriate ratios of Pb+Sb.   The susceptility of these samples have been measured and the structures of the systems have been studied by SEM and XRD. The results of this investigation show that, Although the presence of Pb is essential for formation of (2223 phase, but addition of small amount of Sb helps to stabilize and enhance the ratio of higher phase. Our results show that, presence of Sb would raise the critical current density, but would not affect the Tc of these superconductors.

  9. Measurement of solubility of hydrogen isotopes in Li-Pb by adsorption and desorption method

    International Nuclear Information System (INIS)

    Edao, Yuki; Katayama, K.; Fukada, S.

    2014-01-01

    Measurement of tritium solubility in lithium lead eutectic alloy (Li-Pb) has been performed under the Japan-US collaboration work of 'TITAN'. The present paper reports that results of H and D solubility in Li-Pb which melted in an alumina tube determined by means of a constant volume method, and also reports an experimental apparatus for measurement of tritium solubility in Li-Pb in a tungsten crucible is improved and examined in the STAR facility of the Idaho National Laboratory. It was shown that H solubility in Li-Pb was easily influenced by impurities, interaction with surrounding materials and evaporated Li-Pb. The influences were suggested to be caused by large scattering among the previously reported data on solubility of hydrogen isotopes in Li-Pb. (author)

  10. Sr-Al-Si co-segregated regions in eutectic Si phase of Sr-modified Al-10Si alloy.

    Science.gov (United States)

    Timpel, M; Wanderka, N; Schlesiger, R; Yamamoto, T; Isheim, D; Schmitz, G; Matsumura, S; Banhart, J

    2013-09-01

    The addition of 200 ppm strontium to an Al-10 wt% Si casting alloy changes the morphology of the eutectic silicon phase from coarse plate-like to fine fibrous networks. In order to clarify this modification mechanism the location of Sr within the eutectic Si phase has been investigated by a combination of high-resolution methods. Whereas three-dimensional atom probe tomography allows us to visualise the distribution of Sr on the atomic scale and to analyse its local enrichment, transmission electron microscopy yields information about the crystallographic nature of segregated regions. Segregations with two kinds of morphologies were found at the intersections of Si twin lamellae: Sr-Al-Si co-segregations of rod-like morphology and Al-rich regions of spherical morphology. Both are responsible for the formation of a high density of multiple twins and promote the anisotropic growth of the eutectic Si phase in specific crystallographic directions during solidification. The experimental findings are related to the previously postulated mechanism of "impurity induced twinning". Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Technologies for hydrogen production based on direct contact of gaseous hydrocarbons and evaporated water with Molten Pb or Pb-Bi

    International Nuclear Information System (INIS)

    Gulevich, A. V.; Martynov, P. N.; Gulevsky, V. A.; Ulyanov, V. V.

    2007-01-01

    Results of studies intended for the substantiation of a new energy-saving and safe technology for low cost hydrogen production have been presented. The technology's basis is direct mixing of water and (or) gaseous hydrocarbons with heavy liquid metal coolants (HLMC) Pb or Pb-Bi. Preliminary research has been done on thermal dynamics and kinetics of the processes taking place in the interaction of HLMC with hydrocarbon-containing gases. It has been shown as a result that water and gaseous hydrocarbons interact with molten Pb and Pb-Bi relatively quietly in chemical aspect (without ignition and explosions). Therefore, (and taking into account the thermal physics, physical and chemical properties of HLMC such as low pressure of saturated vapor of Pb and Pb- Bi in enhanced temperatures, their good heat conductivity and heat capacity, low viscosity, etc.) heat transfer is possible from the molten metal to water and hydrocarbons without heat transferring partitions (that is, by direct contact of the working media). Devices to implement this method of heating liquid and gaseous media provide essential advantages: - A simple design; - None heat-transferring surfaces subject to corrosion, contamination, thermal fatigue, vibration impacts; - A high effectiveness owing to a larger heat exchanging surface per volume unit; - A small hydraulic resistance. The possibility and effectiveness of heating various gaseous and liquid media in their direct contact with molten Pb and Pb-Bi has been substantiated convincingly by experimental results at IPPE. Besides, the following processes of hydrogen-containing media conversion have been proved feasible thereby. 1. Water decomposition into hydrogen and oxygen. The process can develop at temperatures of 400-1000 degree C. It is necessary to provide constant removal of oxygen from the reaction zone and maintain a minimum possible content of chemically active oxygen in the melt. 2. Pyrolytic decomposition of hydrocarbons into carbon and

  12. Large-Grain Tin-Rich Perovskite Films for Efficient Solar Cells via Metal Alloying Technique.

    Science.gov (United States)

    Tavakoli, Mohammad Mahdi; Zakeeruddin, Shaik Mohammed; Grätzel, Michael; Fan, Zhiyong

    2018-03-01

    Fast research progress on lead halide perovskite solar cells has been achieved in the past a few years. However, the presence of lead (Pb) in perovskite composition as a toxic element still remains a major issue for large-scale deployment. In this work, a novel and facile technique is presented to fabricate tin (Sn)-rich perovskite film using metal precursors and an alloying technique. Herein, the perovskite films are formed as a result of the reaction between Sn/Pb binary alloy metal precursors and methylammonium iodide (MAI) vapor in a chemical vapor deposition process carried out at 185 °C. It is found that in this approach the Pb/Sn precursors are first converted to (Pb/Sn)I 2 and further reaction with MAI vapor leads to the formation of perovskite films. By using Pb-Sn eutectic alloy, perovskite films with large grain sizes up to 5 µm can be grown directly from liquid phase metal. Consequently, using an alloying technique and this unique growth mechanism, a less-toxic and efficient perovskite solar cell with a power conversion efficiency (PCE) of 14.04% is demonstrated, while pure Sn and Pb perovskite solar cells prepared in this manner yield PCEs of 4.62% and 14.21%, respectively. It is found that this alloying technique can open up a new direction to further explore different alloy systems (binary or ternary alloys) with even lower melting point. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. CFD Simulations of Pb-Bi Two-Phase Flow

    International Nuclear Information System (INIS)

    Dostal, Vaclav; Zelezny, Vaclav; Zacha, Pavel

    2008-01-01

    In a Pb-Bi cooled direct contact steam generation fast reactor water is injected directly above the core, the produced steam is separated at the top and is send to the turbine. Neither the direct contact phenomenon nor the two-phase flow simulations in CFD have been thoroughly described yet. A first attempt in simulating such two-phase flow in 2D using the CFD code Fluent is presented in this paper. The volume of fluid explicit model was used. Other important simulation parameters were: pressure velocity relation PISO, discretization scheme body force weighted for pressure, second order upwind for momentum and CISCAM for void fraction. Boundary conditions were mass flow inlet (Pb-Bi 0 kg/s and steam 0.07 kg/s) and pressure outlet. The effect of mesh size (0.5 mm and 0.2 mm cells) was investigated as well as the effect of the turbulent model. It was found that using a fine mesh is very important in order to achieve larger bubbles and the turbulent model (k-ε realizable) is necessary to properly model the slug flow. The fine mesh and unsteady conditions resulted in computationally intense problem. This may pose difficulties in 3D simulations of the real experiments. (authors)

  14. Liquid-liquid phase separation and solidification behavior of Al55Bi36Cu9 monotectic alloy with different cooling rates

    Science.gov (United States)

    Bo, Lin; Li, Shanshan; Wang, Lin; Wu, Di; Zuo, Min; Zhao, Degang

    2018-03-01

    The cooling rate has a significant effect on the solidification behavior and microstructure of monotectic alloy. In this study, different cooling rate was designed through casting in the copper mold with different bore diameters. The effects of different cooling rate on the solidification behavior of Al55Bi36Cu9 (at.%) immiscible alloy have been investigated. The liquid-liquid phase separation of Al55Bi36Cu9 immiscible alloy melt was investigated by resistivity test. The solidification microstructure and phase analysis of Al55Bi36Cu9 immiscible alloy were performed by the SEM and XRD, respectively. The results showed that the liquid-liquid phase separation occurred in the solidification of Al55Bi36Cu9 monotectic melt from 917 °C to 653 °C. The monotectic temperature, liquid phase separation temperature and immiscibility zone of Al55Bi36Cu9 monotectic alloy was lower than those of Al-Bi binary monotectic alloy. The solidification morphology of Al55Bi36Cu9 monotectic alloy was very sensitive to the cooling rate. The Al/Bi core-shell structure formed when Al55Bi36Cu9 melt was cast in the copper mold with a 8 mm bore diameter.

  15. Potential laboratory health hazard of /sup 210/Pb and a simple procedure for separation of /sup 210/Pb from the daughters /sup 210/Bi and /sup 210/Po

    Energy Technology Data Exchange (ETDEWEB)

    Pounds, J G [Arkansas Univ., Little Rock (USA). Medical Center; Blakemore, W M [The National Center for Toxicological Research, Department of Health and Human Services, Food and Drug Administration, Jefferson, AR, USA

    1981-12-01

    Lead 210 (Radium D) is a naturally occurring radionuclide which is frequently used in toxicological studies due to its long half-life. The use of /sup 210/Pb in tracer studies poses two problems. First /sup 210/Pb, along with its daughters /sup 210/Bi and /sup 210/Po, presents a significant health hazard to laboratory personnel. Second, the presence of the daughter products may interfere with the detection of /sup 210/Pb, particularly by techniques which discriminate poorly between different radioactive emissions, e.g. autoradiography. The potential laboratory health hazards of /sup 210/Pb and its daughters are briefly reviewed and a simple dithiozone extraction procedure which allows quantitative separation of /sup 210/Pb from the daughters /sup 210/Po and /sup 210/Bi is described. The purified /sup 210/Pb may then be utilized to reduce the health hazard from the daughter products and to construct calibration curves for the quantitation of /sup 210/Pb in the presence of /sup 210/Bi and /sup 210/Po by liquid scintillation counting.

  16. Creep Behavior of a Sn-Ag-Bi Pb-Free Solder

    Science.gov (United States)

    Vianco, Paul; Rejent, Jerome; Grazier, Mark; Kilgo, Alice

    2012-01-01

    Compression creep tests were performed on the ternary 91.84Sn-3.33Ag-4.83Bi (wt.%, abbreviated Sn-Ag-Bi) Pb-free alloy. The test temperatures were: −25 °C, 25 °C, 75 °C, 125 °C, and 160 °C (± 0.5 °C). Four loads were used at the two lowest temperatures and five at the higher temperatures. The specimens were tested in the as-fabricated condition or after having been subjected to one of two air aging conditions: 24 hours at either 125 °C or 150 °C. The strain-time curves exhibited frequent occurrences of negative creep and small-scale fluctuations, particularly at the slower strain rates, that were indicative of dynamic recrystallization (DRX) activity. The source of tertiary creep behavior at faster strain rates was likely to also be DRX rather than a damage accumulation mechanism. Overall, the strain-time curves did not display a consistent trend that could be directly attributed to the aging condition. The sinh law equation satisfactorily represented the minimum strain rate as a function of stress and temperature so as to investigate the deformation rate kinetics: dε/dtmin = Asinhn (ασ) exp (−ΔH/RT). The values of α, n, and ΔH were in the following ranges (±95% confidence interval): α, 0.010–0.015 (±0.005 1/MPa); n, 2.2–3.1 (±0.5); and ΔH, 54–66 (±8 kJ/mol). The rate kinetics analysis indicated that short-circuit diffusion was a contributing mechanism to dislocation motion during creep. The rate kinetics analysis also determined that a minimum creep rate trend could not be developed between the as-fabricated versus aged conditions. This study showed that the elevated temperature aging treatments introduced multiple changes to the Sn-Ag-Bi microstructure that did not result in a simple loss (“softening”) of its mechanical strength.

  17. Effect of thermal cycling on the microstructure of a directionally solidified Fe, Cr, Al-TaC eutectic alloy

    Science.gov (United States)

    Harf, F. H.; Tewari, S. N.

    1977-01-01

    Cylindrical bars (1.2 cm diameter) of Fe-13.6Cr-3.7Al-9TaC (wt %) eutectic alloy were directionally solidified in a modified Bridgman type furnace at 1 cm/h. The alloy microstructure consisted of aligned TaC fibers imbedded in a bcc Fe-Cr-Al matrix. Specimens of the alloy were thermally cycled from 1100 to 425 C in a burner rig. The effects of 1800 thermal cycles on the microstructure was examined by scanning electron microscopy, revealing a zig-zag shape of TaC fibers aligned parallel to the growth direction. The mechanism of carbide solution and reprecipitation on the (111) easy growth planes, suggested previously to account for the development of irregular serrations in Co-Cr-Ni matrix alloys, is believed to be responsible for these zig-zag surfaces.

  18. Magnetic susceptibility of Dirac fermions, Bi-Sb alloys, interacting Bloch fermions, dilute nonmagnetic alloys, and Kondo alloys

    Energy Technology Data Exchange (ETDEWEB)

    Buot, Felix A., E-mail: fbuot@gmu.edu [Computational Materials Science Center, George Mason University, Fairfax, VA 22030 (United States); TCSE Center, Spintronics Group, Physics Department, University of San Carlos, Talamban, Cebu 6000 (Philippines); C& LB Research Institute, Carmen, Cebu 6005 (Philippines); Otadoy, Roland E.S.; Rivero, Karla B. [TCSE Center, Spintronics Group, Physics Department, University of San Carlos, Talamban, Cebu 6000 (Philippines)

    2017-03-01

    Wide ranging interest in Dirac Hamiltonian is due to the emergence of novel materials, namely, graphene, topological insulators and superconductors, the newly-discovered Weyl semimetals, and still actively-sought after Majorana fermions in real materials. We give a brief review of the relativistic Dirac quantum mechanics and its impact in the developments of modern physics. The quantum band dynamics of Dirac Hamiltonian is crucial in resolving the giant diamagnetism of bismuth and Bi-Sb alloys. Quantitative agreement of the theory with the experiments on Bi-Sb alloys has been achieved, and physically meaningful contributions to the diamagnetism has been identified. We also treat relativistic Dirac fermion as an interband dynamics in uniform magnetic fields. For the interacting Bloch electrons, the role of translation symmetry for calculating the magnetic susceptibility avoids any approximation to second order in the field. The expressions for magnetic susceptibility of dilute nonmagnetic alloys give a firm theoretical foundation of the empirical formulas used in fitting experimental results. The unified treatment of all the above calculations is based on the lattice Weyl-Wigner formulation of discrete phase-space quantum mechanics. For completeness, the magnetic susceptibility of Kondo alloys is also given since Dirac fermions in conduction band and magnetic impurities exhibit Kondo effect.

  19. Influence of Lanthanum on Solidification, Microstructure, and Mechanical Properties of Eutectic Al-Si Piston Alloy

    Science.gov (United States)

    Ahmad, R.; Asmael, M. B. A.

    2016-07-01

    The effects of Lanthanum (La) concentration on the solidification parameters of the α-Al, Al-Si, and Al-Cu phases and on the microstructure, tensile, and hardness properties of eutectic Al-Si-Cu-Mg alloy were systematically investigated. The solidification parameters were examined using computer-aided cooling curve thermal analysis (CA-CCTA). The cooling curve and microstructure analysis showed that La altered the Si structure. The nucleation and growth temperatures of eutectic Si decreased when 0.3 wt.% La was added, and a high depression temperature was obtained with 1.0 wt.% La. High amounts of La considerably modified the Si structure and decreased the area and aspect ratio by 69.9 and 51%, respectively. The thermal analysis result recorded a faster freezing time with the La addition and a 36% alteration in the secondary dendrite arm spacing. Two secondary or ternary La-rich intermetallic phases were formed with needle- and plate-like structures. Furthermore, the mechanical properties were investigated by hardness and tensile tests with different La concentrations. The addition of small amounts of La (0.1 wt.%) significantly improved the ultimate tensile strength and quality index of the Al-Si-Cu-Mg alloy. In addition, the hardness value of Al-11Si-Cu increased by 7-8% with the increasing amount of La added.

  20. An electrical resistivity monitor for the detection of composition changes in Pb-17Li

    International Nuclear Information System (INIS)

    Hubberstey, P.; Barker, M.G.; Sample, T.

    1991-01-01

    An electrical resistivity monitor for the detection of composition changes in the lithium-lead eutectic alloy, Pb-17Li, has been developed. A miniature electromagnetic pump is used to sample alloy continuously from a pool or loop system and force it through a capillary section, within which the necessary resistance measurements are made, prior to its return to the bulk source. To calibrate the monitor, detailed resistivity-temperature and resistivity-composition data have been determined for Pb-Li alloys at temperatures from 600 to 800K and compositions from 0 to 20.5 at% Li. The resistivity increases with both temperature and composition; for Pb-17li at 723 K, dρ/dT=0.054x10 -8 ΩmK -1 , and dρ/d[Li]=1.27x10 -8 Ωm(at% Li) -1 . The sensitivity of the monitor is such that changes in composition of as little as ±0.05 at% Li can be detected and its response time is limited soley by the rate of sampling. (orig.)

  1. Preparation, deformation, and failure of functional Al-Sn and Al-Sn-Pb nanocrystalline alloys

    Science.gov (United States)

    Noskova, N. I.; Vil'Danova, N. F.; Filippov, Yu. I.; Churbaev, R. V.; Pereturina, I. A.; Korshunov, L. G.; Korznikov, A. V.

    2006-12-01

    Changes in the structure, hardness, mechanical properties, and friction coefficient of Al-30% Sn, Al-15% Sn-25% Pb, and Al-5% Sn-35% Pb (wt %) alloys subjected to severe plastic deformation by equal-channel angular pressing (with a force of 40 tonne) and by shear at a pressure of 5 GPa have been studied. The transition into the nanocrystalline state was shown to occur at different degrees of plastic deformation. The hardness exhibits nonmonotonic variations, namely, first it increases and subsequently decreases. The friction coefficient of the Al-30% Sn, Al-15% Sn-25% Pb, and Al-5% Sn-35% Pb alloys quenched from the melt was found to be 0.33; the friction coefficients of these alloys in the submicrocrystalline state (after equal-channel angular pressing) equal 0.24, 0.32, and 0.35, respectively. The effect of disintegration into nano-sized powders was found to occur in the Al-15% Sn-25% Pb, and Al-5% Sn-35% Pb alloys after severe plastic deformation to ɛ = 6.4 and subsequent short-time holding.

  2. Magnetic anisotropy induced by crystallographic orientation and morphological alignment in directionally-solidified eutectic Mn-Sb alloy

    Energy Technology Data Exchange (ETDEWEB)

    Lou, Chang-Sheng [School of Materials Science and Engineering, Shenyang Ligong University, Shenyang 110159 (China); Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China); Liu, Tie, E-mail: liutie@epm.neu.edu.cn [Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China); Dong, Meng; Wu, Chun; Shao, Jian-Guo; Wang, Qiang [Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China)

    2017-02-15

    The influences of the crystallographic orientation and morphological alignment upon the magnetic anisotropic behavior of polycrystalline materials were investigated. Microstructures obtained in eutectic Mn-Sb alloys via directional solidification simultaneously displayed crystallographic orientation and morphological alignment. Both the crystallographic orientation and the morphological alignment were able to induce magnetic anisotropy in the alloys, wherein the influence of the crystallographic orientation and the morphological alignment upon the magnetic anisotropic behavior of the alloys strongly depended upon their directions and exhibited either mutual promotion or competition. These findings may provide useful guidance for the fabrication design of functional magnetic materials. - Highlights: • We study effects of orientation in crystal and morphology on magnetic anisotropy. • Both orientation in crystal and morphology can induce magnetic anisotropy. • Their effects depend on direction and exhibit either mutual promotion or competition.

  3. Solidification of Bi2Sr2Ca1Cu2Oy and Bi2Sr1.75Ca0.25CuOy

    International Nuclear Information System (INIS)

    Holesinger, T.G.; Miller, D.J.; Viswanathan, H.K.; Chumbley, L.S.

    1993-01-01

    The solidification processes for the compositions Bi 2 Sr 2 CaCu 2 O y (2212) and Bi 2 Sr 1.75 Ca 0.25 CuO y (2201) were determined as a function of oxygen partial pressure. During solidification in argon, the superconducting phases were generally not observed to form for either composition. In both cases, the solidus is lowered to approximately 750 degree C. Solidification of Bi 2 Sr 1.75 Ca 0.25 CuO y in Ar resulted in a divorced eutectic structure of Bi 2 Sr 2-x Ca x O y (22x) and Cu 2 O while solidification of Bi 2 Sr 2 CaCu 2 O y in Ar resulted in a divorced eutectic structure of Bi 2 Sr 3-x Ca x O y (23x) and Cu 2 O. Solidification of Bi 2 Sr 1.75 Ca 0.25 CuO y in O 2 resulted in large grains of 2201 interspersed with small regions containing the eutectic structure of 22x and CuO/Cu 2 O. Solidification of Bi 2 Sr 2 CaCu 2 O y in partial pressures of 1%, 20%, and 100% oxygen resulted in multiphase samples consisting of 2212, 2201, some alkaline-earth cuprates, and both divorced eutectic structures found during solidification in Ar. For both compositions, these latter structures can be attributed to oxygen deficiencies present in the melt regardless of the overpressure of oxygen. These eutectic structures are unstable and convert into the superconducting phases during subsequent anneals in oxygen. The formation process of the 2212 phase during solidification from the melt was determined to proceed through an intermediate state involving the 2201 phase

  4. Evidence of eutectic crystallization and transient nucleation in Al89La6Ni5 amorphous alloy

    International Nuclear Information System (INIS)

    Zhuang, Y. X.; Jiang, J. Z.; Lin, Z. G.; Mezouar, M.; Crichton, W.; Inoue, A.

    2001-01-01

    The phase evolution with the temperature and time in the process of crystallization of Al 89 La 6 Ni 5 amorphous alloy has been investigated by in situ high-temperature and high-pressure x-ray powder diffraction using synchrotron radiation. Two crystalline phases, fcc-Al and a metastable bcc-(AlNi) 11 La 3 -like phase, were identified after the first crystallization reaction, revealing a eutectic reaction instead of a primary reaction suggested in the literature. Time-dependent nucleation in the amorphous alloy is detected and the experimental data can be fitted by both the Zeldovich's and Kashchiev's transient nucleation models with transient nucleation times of 220 and 120 min, respectively. Copyright 2001 American Institute of Physics

  5. Growth of nucleation sites on Pb-doped Bi2Sr2Ca1Cu2O8+δ

    International Nuclear Information System (INIS)

    Finnemore, D.K.; Xu, M.; Kouzoudis, D.; Bloomer, T.; Kramer, M.J.; McKernan, S.; Balachandran, U.; Haldar, P.

    1996-01-01

    In the growth of Bi 2 Sr 2 Ca 2 Cu 3 O 10+δ from mixed powders of Pb-doped Bi 2 Sr 2 Ca 1 Cu 2 O 8+δ and other oxides, it has been discovered that a dense array of hillocks or mesas grow at the interface between a Ag overlay and Pb-doped Bi 2 Sr 2 Ca 1 Cu 2 O 8+δ grains during the ramp up to the reaction temperature. As viewed in an environmental scanning electron microscope, the Ag coated grains develop a texture that looks like open-quote open-quote chicken pox close-quote close-quote growing on the grains at about 700 degree C. These hillocks are about 100 nm across and are spaced at about 500 to 1000 nm. If there is no Ag, this texture does not develop. Preliminary measurements indicate that the hillocks are a recrystallization of (Bi,Pb) 2 Sr 2 Ca 1 Cu 2 O 8+δ , and are definitely not a Pb rich phase. copyright 1996 American Institute of Physics

  6. Formation of anomalous eutectic in Ni-Sn alloy by laser cladding

    Science.gov (United States)

    Wang, Zhitai; Lin, Xin; Cao, Yongqing; Liu, Fencheng; Huang, Weidong

    2018-02-01

    Ni-Sn anomalous eutectic is obtained by single track laser cladding with the scanning velocity from 1 mm/s to 10 mm/s using the Ni-32.5 wt.%Sn eutectic powders. The microstructure of the cladding layer and the grain orientations of anomalous eutectic were investigated. It is found that the microstructure is transformed from primary α-Ni dendrites and the interdendritic (α-Ni + Ni3Sn) eutectic at the bottom of the cladding layer to α-Ni and β-Ni3Sn anomalous eutectic at the top of the cladding layer, whether for single layer or multilayer laser cladding. The EBSD maps and pole figures indicate that the spatially structure of α-Ni phase is discontinuous and the Ni3Sn phase is continuous in anomalous eutectic. The transformation from epitaxial growth columnar at bottom of cladding layer to free nucleation equiaxed at the top occurs, i.e., the columnar to equiaxed transition (CET) at the top of cladding layer during laser cladding processing leads to the generation of anomalous eutectic.

  7. Bi-Abundance Ionisation Structure of the Wolf-Rayet Planetary Nebula PB 8

    Science.gov (United States)

    Danehkar, A.

    2018-01-01

    The planetary nebula PB 8 around a [WN/WC]-hybrid central star is one of planetary nebulae with moderate abundance discrepancy factors (ADFs 2-3), which could be an indication of a tiny fraction of metal-rich inclusions embedded in the nebula (bi-abundance). In this work, we have constructed photoionisation models to reproduce the optical and infrared observations of the planetary nebula PB 8 using a non-LTE stellar model atmosphere ionising source. A chemically homogeneous model initially used cannot predict the optical recombination lines. However, a bi-abundance model provides a better fit to most of the observed optical recombination lines from N and O ions. The metal-rich inclusions in the bi-abundance model occupy 5.6% of the total volume of the nebula, and are roughly 1.7 times cooler and denser than the mean values of the surrounding nebula. The N/H and O/H abundance ratios in the metal-rich inclusions are 1.0 and 1.7 dex larger than the diffuse warm nebula, respectively. To reproduce the Spitzer spectral energy distribution of PB 8, dust grains with a dust-to-gas ratio of 0.01 (by mass) were also included. It is found that the presence of metal-rich inclusions can explain the heavy element optical recombination lines, while a dual-dust chemistry with different grain species and discrete grain sizes likely produces the infrared continuum of this planetary nebula. This study demonstrates that the bi-abundance hypothesis, which was examined in a few planetary nebulae with large abundance discrepancies (ADFs > 10), could also be applied to those typical planetary nebulae with moderate abundance discrepancies.

  8. Effect of the roughness of crucible on viscosity of liquid Pb38.1Sn61.9 alloy

    International Nuclear Information System (INIS)

    Wu Yuqin; Bian Xiufang; Mao Tan; Li Xuelian; Li Taibao; Wang Caidong

    2007-01-01

    The viscosity of the eutectic Pb 38.1 Sn 61.9 alloy has been measured by a torsional oscillation viscometer using three different crucibles which are made of the materials of highly sintered alumina (Al 2 O 3 ), quartz (SiO 2 ), and graphite (C) respectively. The roughness of crucibles has effect on the viscosity. The viscosity data obtained for SiO 2 and C crucibles were concentrated in the narrow range of about 0.5% and showed almost the same activation energy. However, the viscosity obtained using Al 2 O 3 crucible with the maximal roughness is higher than that using the other two crucibles. The discrepancy of viscosity obtained using those crucibles increases with the viscosity. In addition, the viscosity obtained using three kinds of crucibles in our work has a breakpoint at 488 K, which is approximate with the results of electrical conductivity and thermopower measurements reported by Plevachuk et al., which indicates the microstructure in melt changes before solidification

  9. Phase equilibria and homogeneity range of the high temperature superconducting compound (Bi,Pb)2+xSr2Ca2Cu3O10+δ

    International Nuclear Information System (INIS)

    Kaesche, S.

    1995-01-01

    For the superconducting cuprates (Bi,Pb) 2+x Sr 2 Ca 2 Cu 3 O 10+y phase equilibria, the homogeneity region, and the phase formation has been studied in the temperture range 800 to 890 C. Sintered samples were prepared by a solid state reaction starting from Bi 2 O 3 , PbO, CuO and carbonates CaCO 3 and SrCO 3 in a three-stage calcination process. For the phase identification polarization microscopy, X-ray diffraction and susceptibility measurements have been applied. Multi-phase regions were determined in the cross section of the quasi-ternary system (Bi,Pb) 2 O 3 -SrO-CaO-CuO with constant Bi/(Bi+Pb) ratio 0.84 taking into account the 2223-phase. The homogeneity region was determined as function of Sr, Ca, Bi and Pb concentration. Its maximum size was found at 850 C

  10. Phase-field model of eutectic growth

    International Nuclear Information System (INIS)

    Karma, A.

    1994-01-01

    A phase-field model which describes the solidification of a binary eutectic alloy with a simple symmetric phase diagram is introduced and the sharp-interface limit of this model is explored both analytically and numerically

  11. Synthesis and evaluation of tetraphosphonates labelled with 212Bi, 212Pb and 165Er

    International Nuclear Information System (INIS)

    Hassfjell, S.P.

    1997-08-01

    The main goal of this work has been to achieve a synthesis of radiolabelled phosphonates for the improvement of diagnostic and therapy of osteoblastic osteosarcoma and sclerotic bone metastases. 212 Bi-DOTMP is shown to be an in vivo stable bone seeking radiopharmaceutical with a potential for a α-particle therapy of the above mentioned diseases. It has biodistribution characteristics similar to 153 Sm-EDTMP, which is now formally approved in several countries, most recently in the US. 212 Pb-DOTMP is also a promising candidate having the advantage of increasing the effective half life of the α-emitter, although loss of some of the in vivo generated 212 Bi may be a problem. A generator has been developed for the production of the α-emitting radionuclide 212 Bi and its parent nuclide 212 Pb. The generator is based on the emanation of 220 Rn from ( 228 Th)barium stearate. The decay product of 220 Rn, 212 Pb deposits on the walls of a polyethylene bottle, and can be wasted off with distilled water. The generator shows no leakage of any long-lived parent nuclides, is easy to operate and has a high degree of radiation safety

  12. Effects of aging time on the mechanical properties of Sn–9Zn–1.5Ag–xBi lead-free solder alloys

    International Nuclear Information System (INIS)

    Liu, Chih-Yao; Hon, Min-Hsiung; Wang, Moo-Chin; Chen, Ying-Ru; Chang, Kuo-Ming; Li, Wang-Long

    2014-01-01

    Highlights: • The microstructure of these solder alloys are composed of Sn-rich phase and Ag 3 Sn. • The grain size of Sn–9Zn–1.5Ag–xBi solder alloys increases with rose aging time. • The maximum yield strength is 112.7 ± 2.2 MPa for Sn–9Zn–1.5Ag–3Bi solder alloys. • TEM observed that Bi appears as oblong shape fine particles. -- Abstract: The effects of aging time on the mechanical properties of the Sn–9Zn–1.5Ag–xBi lead-free solder alloys are investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive spectrometry (EDS) and a universal testing machine. The experimental results show that the microstructure of Sn–9Zn–1.5Ag–xBi solder alloys is composed of Sn-rich phase and AgZn 3 . No other intermetallic compounds (IMCs) with Bi content was observed in the solder matrix for Sn–9Zn–1.5Ag solder alloys with various Bi contents before and after aging at 150 °C for different durations. The lattice parameter increases significantly with increasing aging time or Bi addition. The size of Sn-rich grain increased gradually with aging time increased, but decreases with Bi content increases. The maximum yield strength is 112.7 ± 2.2 MPa for Sn–9Zn–1.5Ag–3Bi solder alloy before aging

  13. Effects of aging time on the mechanical properties of Sn–9Zn–1.5Ag–xBi lead-free solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chih-Yao [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Hon, Min-Hsiung [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80782, Taiwan (China); Wang, Moo-Chin, E-mail: mcwang@kmu.edu.tw [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100, Shih-Chuan 1st Road, Kaohsiung 80728, Taiwan (China); Chen, Ying-Ru; Chang, Kuo-Ming; Li, Wang-Long [Institute of Nanotechnology and Microsystems Engineering, National Cheng Kung University, No. 1, University Road, Tainan 70101, Taiwan (China)

    2014-01-05

    Highlights: • The microstructure of these solder alloys are composed of Sn-rich phase and Ag{sub 3}Sn. • The grain size of Sn–9Zn–1.5Ag–xBi solder alloys increases with rose aging time. • The maximum yield strength is 112.7 ± 2.2 MPa for Sn–9Zn–1.5Ag–3Bi solder alloys. • TEM observed that Bi appears as oblong shape fine particles. -- Abstract: The effects of aging time on the mechanical properties of the Sn–9Zn–1.5Ag–xBi lead-free solder alloys are investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive spectrometry (EDS) and a universal testing machine. The experimental results show that the microstructure of Sn–9Zn–1.5Ag–xBi solder alloys is composed of Sn-rich phase and AgZn{sub 3}. No other intermetallic compounds (IMCs) with Bi content was observed in the solder matrix for Sn–9Zn–1.5Ag solder alloys with various Bi contents before and after aging at 150 °C for different durations. The lattice parameter increases significantly with increasing aging time or Bi addition. The size of Sn-rich grain increased gradually with aging time increased, but decreases with Bi content increases. The maximum yield strength is 112.7 ± 2.2 MPa for Sn–9Zn–1.5Ag–3Bi solder alloy before aging.

  14. The effect of Bi{sub In} hetero-antisite defects in In{sub 1–x}PBi{sub x} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Liyuan [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, P.O. Box 72, Beijing 100876 (China); Lu, Pengfei, E-mail: photon.bupt@gmail.com [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, P.O. Box 72, Beijing 100876 (China); State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Yang, Chuanghua [School of Physics and Telecommunication Engineering, Shanxi University of Technology (SNUT), Hanzhong 723001, Shaanxi (China); Liang, Dan [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, P.O. Box 72, Beijing 100876 (China); Zhang, Chunfang [Beijing Computational Science Research Center, Beijing 100094 (China); Wang, Shumin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Photonics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Gothenburg (Sweden)

    2016-07-25

    Bi{sub In} hetero-antisite defects in InP:Bi alloy is performed by using first-principle calculations. It is found that the hetero-antisite defect Bi{sub In} is energetically easier than Bi{sub P}. This Bi{sub In} defect is a deep level donor, and the related defect band is introduced by the sp-hybridization mainly between the 6s state of Bi{sub In} and 3p states of the nearest P atoms. The band gap of InP:Bi alloy increases slightly with the increase of Bi compositions, and the relative position of the defect level remains almost unchanged. These results represent that hetero-antisite defect Bi{sub In} does not contribute to the reduction of the band gap of InP:Bi alloy. The calculations of optical properties show that hetero-antisite defect Bi{sub In} can contribute to the red shift phenomena observed in experiment as the Bi composition increases. In addition, the interaction of two Bi{sub In} atoms can result in the split of the impurity band and cause a strong absorption in near-infrared region, indicating it can be a potential candidate for optoelectronics application. - Highlights: • The effects of Bi{sub In} hetero-antisite defects in InP:Bi alloy are studied. • The appearance and origin of Bi{sub In} related impurity band are discovered. • Bi{sub In} defects can contribute to the red shift phenomena observed in experiment. • A strong absorption in near-infrared region caused by two Bi{sub In} atoms is found.

  15. Gamma ray shielding characteristic of BiZnBo-SLS and PbZnBo-SLS glass

    Science.gov (United States)

    Syuhada Ahmad, Nor; Shahrim Mustafa, Iskandar; Mansor, Ishak; Malik, Muhammad Fadhirul Izwan bin Abdul; Ain Nabilah Razali, Nur; Nordin, Sufiniza

    2018-05-01

    The radiation shielding and optical properties of x [RmOn] (0.5‑x) [ZnO] 0.2 [B2O3] 0.3 [SLS], where RmOn are Bi2O3 and PbO with x = 0.05, 0.10, 0.20, 0.30, 0.40, and 0.45 have been prepared by using the melt-quenching method at 1200 °C and was investigated on their physical, structural and gamma ray shielding properties. Field-emission scanning electron microscope (FESEM) data revealed that the particle morphologies is aggregated and irregular in shapes and size. Energy dispersive x-ray spectroscopy (EDS) elemental mapping data confirmed that all mentioned element all present on the prepared glass. Soda Lime Silica (SLS) that is mainly composed of SiO2 has been utilized in this study as the source of SiO2 for fabrication of glass system. From the result, the density and molar volume of both glass samples increased as Bi2O3 and PbO content increased. The gamma ray shielding properties, such as linear attenuation and mass attenuation coefficient, were increased while half value layer (HVL) and mean free path (MFP) were decreased as the increased in Bi2O3 and PbO concentrations. It is recognized that the mass attenuation coefficient value of Bi2O3 and PbO glass are slightly different. From this study, it can be concluded that from the non-toxicity and shielding point of view, the bismuth glass is a good shield to gamma radiation as compared to lead glass.

  16. Synthesis and magnetic properties of rare-earth free MnBi alloy: A high-energy hard magnetic material

    Science.gov (United States)

    Sharma, Sanjeev Kumar; Prakash, H. R.; Ram, S.; Pradhan, D.

    2018-04-01

    MnBi is a rare-earth free high-energy magnetic material useful for the permanent magnet based devices. In a simple method, a MnBi alloy was prepared by arc melting method using Mn and Bi metals in 60:40 atomic ratio. In terms of the X-ray diffraction, a crystalline MnBi phase is formed with Bi as impurity phase of the as-prepared alloy. FESEM image of chemically etched sample shows small grains throughout the alloy. SEAD pattern and lattice image were studied to understand the internal microstructure of the alloy. The thermomagnetic curves measured in ZFC-FC cycles over 5-380 K temperatures at 500 Oe field, shows the induced magnetization of 5-25 % in the sample. The coercivity values, 7.455 kOe (13.07 emu/g magnetization) at 380 K, and 5.185k Oe (14.75 emu/g magnetization) at 300 K, are observed in the M-H hysteresis loops. A decreased value 0.181kOe (18.05 emu/g magnetization) appears at 100 K due to the change in the magnetocrystalline anisotropy. The results are useful to fabricate small MnBi magnets for different permanent magnets based devices.

  17. Study of the Neutron Deficient Pb and Bi Isotopes by Simultaneous Atomic- and Nuclear-Spectroscopy

    CERN Multimedia

    Kessler, T

    2002-01-01

    We propose to study systematically nuclear properties of the neutron deficient lead $^{183-189}$Pb, $^{191g}$Pb, $^{193g}$Pb and bismuth isotopes $^{188-200}$Bi by atomic spectroscopy with the ISOLDE resonance ionisation laser ion source (RILIS) combined with simultaneous nuclear spectroscopy at the detection set-up. The main focus is the determination of the mean square charge radii of $^{183-190}$Pb and $^{188-193}$Bi from which the influence of low-lying intruder states should become obvious. Also the nuclear spin and magnetic moments of ground-states and long-lived isomers will be determined unambiguously through evaluation of the hyperfine structure, and new isomers could be discovered. The decay properties of these nuclei can be measured by $\\alpha$-$\\gamma$ and $\\beta$-$\\gamma$ spectroscopy. With this data at hand, possible shape transitions around mid-shell at N$\\sim$104 will be studied. This data is crucial for the direct test of nuclear theory in the context of intruder state influence (e.g. energy ...

  18. Environmental radioactivity of radon daughter's radionuclides 210Pb-210Bi-210Po

    International Nuclear Information System (INIS)

    Momoshima, N.

    2003-01-01

    Radionuclide, 210 Pb(22.3 y)- 210 Bi(5.013 d)- 210 Po(138.4 d) belongs to the uranium decay chain and widely distributed in the environment. 222 Rn escaped from the earth surface is a major source of atmospheric 210 Pb. These nuclides attach with atmospheric aerosols and are removed to the ground as wet and dry depositions. The residence time of the atmospheric aerosol, thus, was obtained by activity ratios of 210 Bi/ 210 Pb and 210 Po/ 210 Pb, showing different values. The discrepancy on the residence times are explained with inputs of 210 Po to the atmosphere other than 222 Rn emanated from the earth surface. The removal of aerosol as wet deposition occupies a significant fraction, which reaches 72% on 210 Pb and 89% on 7 Be. In the ocean, the radionuclides are used as tracer to examine dynamic processes occurring in the ocean, such as removal of particulate matter from seawater column to bottom. The 210 Pb and 210 Po concentrations in the ocean water collected off continent decreased from surface toward bottom, and the shortage on 210 Po content relative to that of 210 Po was observed at shallow ocean layers, however, the 210 Po/ 210 Pb activity ratio closed to the radioactive equilibrium at deeper layers. The 210 Pb is a very good tracer to evaluate an accumulation rate of bottom sediment in ocean, lake and river. This is called as 210 Pb dating and is successfully applicable to accumulation circumstances that bottom sediment deposits at constant rate. Most of the actual cases, simultaneous 137 Cs dating is carried out, which uses 137 Cs peak in the core as originated from radioactive fallout of nuclear tests, showing the maximum in 1963. Recently new findings on source of atmospheric 210 Po are report by laboratory experiments and environmental measurements, which proves biologically supported emission of volatile Po compounds to the atmosphere. (author)

  19. Heterogeneous coarsening of Pb phase and the effect of Cu addition on it in a nanophase composite of Al-10 wt%Pb alloy prepared by mechanical alloying

    International Nuclear Information System (INIS)

    Zhu, M.; Liu, X.; Wu, Z.F.; Ouyang, L.Z.; Zeng, M.Q.

    2009-01-01

    A nanophase composite of Al-10 wt%Pb alloy was prepared by mechanical alloying. The coarsening behavior of Pb phase in the composite during heating process was investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nanoindentation test. The present work shows that the Pb phase grew substantially and had two different size distributions when the heating temperature was above 823 K. The different size distributions of Pb phase were owing to different grain size ranges of Al matrix in different regions, which led to the different growth rates of the Pb phase in those regions. It has been proposed that the different size ranges of Al grain appeared upon heating were originated from a statistical size distribution of Al grains in the as-milled powder. With the addition of a small amount of Cu, the heterogeneous growth of Pb phase can be suppressed, and the coarsening of Pb phase shows two distinct rates. This indicates that the coarsening is mainly governed by grain boundary diffusion and lattice diffusion of Al matrix in the initial stage and the later one, respectively

  20. Developments of 207Pb, 208Pb and 209Bi target wheels in the synthesis of 107Ns, 108Hs and 109Mt

    International Nuclear Information System (INIS)

    Folger, H.; Hartmann, W.; Hessberger, F.P.; Hofmann, S.; Klemm, J.; Muenzenberg, G.; Ninov, V.; Schmidt, K.H.; Schoett, H.J.; Thalheimer, W.; Armbruster, P.

    1993-05-01

    The developments of 207 Pb, 208 Pb and 209 Bi target wheels and their applications in heavy-ion fusion reactions are reviewed. In both, fabrication and use, the centers of the evaporator or accelerator beams are focussed at wheel radii of 155 mm to specially shaped frames which generate very homogeneous target layers and very constant reaction and counting rates in the experiment. Target areas of up to ∼98% of a wheel's circumference of 974 mm can be provided. The preparation procedures for necessary C backings and protecting layers of C are described, and details are given for the developments of high-vacuum evaporations of 207 Pb, 208 Pb and 209 Bi with deposition yields of 35-55% from tantalum crucibles. The applications of the target wheels in heavy-ion fusion reactions with beams of 54 Cr and 58 Fe at energies near the Coulomb barrier and intensities of ∼10 12 particles/s are mentioned. The target parameters for the production runs of the new chemical elements 107 Ns, 108 Hs and 109 Mt are included. (orig.)

  1. Ag doped (Bi1.6Pb0.4Sr2CaCu2O8+δ textured rods

    Directory of Open Access Journals (Sweden)

    Díez, J. C.

    2008-06-01

    Full Text Available In this work, superconducting samples of (Bi1.6Pb0.4Sr2CaCu2O8+δ with Ag additions have been studied. (Bi1.6Pb0.4Sr2CaCu2O8+δ + x wt.% Ag (with x = 0, 1 and 3 powders were synthesized using a sol-gel method. The obtained powders were used as precursors to fabricate long textured cylindrical bars through a floating zone melting method. A drastic change on the microstructure has been found when comparing with undoped Bi2Sr2CaCu2O8+δ samples. The results showed that electrical resistivity at room temperature, critical current as well as flexural strength are improved when Ag is added to these Pb doped samples, while critical temperature does not change. On the other hand, it has been found that samples with composition (Bi1.6Pb0.4Sr2CaCu2O8+δ + Ag shown E-I curves with very high sharpness values on the zone of the superconducting to normal transition, reaching n-values (E∼In as high as 45 at 65K.Se han preparado polvos cerámicos de composición (Bi1.6Pb0.4Sr2CaCu2O8+δ + x % Ag en peso (con x = 0, 1 y 3 mediante un proceso sol-gel. Estos polvos se han utilizado para fabricar precursores que se texturaron por medio del método de fusión zonal flotante. Se ha encontrado un gran cambio en la microestructura cuando se compara con muestras de composición pura Bi2Sr2CaCu2O8+δ. Tanto la resistividad eléctrica a temperatura ambiente, como la corriente crítica, así como la resistencia a flexión se mejoran cuando la Ag se adiciona a estas muestras dopadas con Pb, mientras que no se observa cambio en la temperatura crítica. Por otra parte, se ha encontrado que las muestras de composición (Bi1.6Pb0.4Sr2CaCu2O8+δ + Ag presentan una gran pendiente de la curva E-I en la zona de transición entre el estado superconductor y el estado normal. Con estas composiciones, se han encontrado valores de n (E∼In de hasta 45 a 65K.

  2. Synthesis and photoelectrical performance of nanoscale PbS and Bi2S3 co-sensitized on Ti02 nanotube arrays

    Institute of Scientific and Technical Information of China (English)

    Fanggong Cai; Min Pan; Yong Feng; Guo Yan; Yong Zhang; Yong Zhao

    2017-01-01

    TiO2 films have been widely applied in photovoltaic conversion techniques.TiO2 nanotube arrays (TiO2 NAs) can be grown directly on the surface of metal Ti by the anodic oxidation method.Bi2S3 and PbS nanoparticles (NPs) were firstly co-sensitized on TiO2 NAs (denoted as PbS/Bi2S3(n)/TiO2 NAs) by a two-step process containing hydrothermal and sonication-assisted SILAR method.When the concentration of Bi3+ is 5 mmol/L,the best photoelectrical performance was obtained under simulated solar irradiation.The short-circuit photocurrent (Jsc) and photoconversion efficiency (η) of PbS/Bi2S3(5)/TiO2 NAs electrode were 4.70 mA/cm and 1.13 %,respectively.

  3. Hot corrosion resistance of a Pb-Sb alloy for lead acid battery grids

    Energy Technology Data Exchange (ETDEWEB)

    Osorio, Wislei R.; Garcia, Amauri [Department of Materials Engineering, University of Campinas - UNICAMP, PO Box 6122, 13083-970 Campinas, SP (Brazil); Aoki, Claudia S.C. [Research and Development Centre - CPqD Foundation, Rod. Campinas/Mogi, km 118.5, 13086-912 Campinas, SP (Brazil)

    2008-12-01

    The aim of this study was to evaluate the effects of the microstructural morphologies of a Pb-6.6 wt%Sb alloy on the resulting corrosion resistance in a 0.5 M H{sub 2}SO{sub 4} solution at different temperatures: environment temperature, 50 C and 70 C. A water-cooled unidirectional solidification system was employed permitting a wide range of microstructures to be analyzed. Electrochemical impedance spectroscopy (EIS) diagrams, potentiodynamic polarization curves and an equivalent circuit analysis were used to evaluate the corrosion behavior of the Pb-Sb alloy samples. It was found that with increasing temperatures the general corrosion resistance of Pb-Sb dendritic alloys decreases, and that independently of the working temperature finer dendritic spacings exhibit better corrosion resistance than coarser ones. (author)

  4. Valence band structure of InAs(1-x)Bi(x) and InSb(1-x)Bi(x) alloy semiconductors calculated using valence band anticrossing model.

    Science.gov (United States)

    Samajdar, D P; Dhar, S

    2014-01-01

    The valence band anticrossing model has been used to calculate the heavy/light hole and spin-orbit split-off energies in InAs(1-x)Bi(x) and InSb(1-x)Bi(x) alloy systems. It is found that both the heavy/light hole, and spin-orbit split E + levels move upwards in energy with an increase in Bi content in the alloy, whereas the split E - energy for the holes shows a reverse trend. The model is also used to calculate the reduction of band gap energy with an increase in Bi mole fraction. The calculated values of band gap variation agree well with the available experimental data.

  5. Synthesis of bulk nanocrystalline Pb-Sn-Te alloy under high pressure

    International Nuclear Information System (INIS)

    Zhu, P W; Chen, L X; Jia, X; Ma, H A; Ren, G Z; Guo, W L; Liu, H J; Zou, G T

    2002-01-01

    Pb-Sn-Te bulk nanocrystalline (NC) materials are prepared successfully by quenching melts under high pressure. The mean particle size is about 100 nm and the crystal structure is NaCl type. The mechanism of formation of the bulk NC alloy is explained: there is an increasing of the nucleation rate and a decrease in the growth rate of nuclei with increase of pressure during the solidification processes. The thermoelectric properties of Pb-Sn-Te bulk NC alloy are enhanced. This method is promising for producing thermoelectric materials with improved high-energy conversion efficiency

  6. The preferential orientation and lattice misfit of the directionally solidified Fe-Al-Ta eutectic composite

    Science.gov (United States)

    Cui, Chunjuan; Wang, Pei; Yang, Meng; Wen, Yagang; Ren, Chiqiang; Wang, Songyuan

    2018-01-01

    Fe-Al intermetallic compound has been paid more attentions recently in many fields such as aeronautic, aerospace, automobile, energy and chemical engineering, and so on. In this paper Fe-Al-Ta eutectic was prepared by a modified Bridgman directional solidification technique, and it is found that microstructure of the Fe-Al-Ta eutectic alloy transforms from the broken-lamellar eutectic to cellular eutectic with the increase of the solidification rate. In the cellular eutectic structure, the fibers are parallel to each other within the same grain, but some fibers are deviated from the original orientation at the grain boundaries. To study the crystallographic orientation relationship (OR) between the two phases, the preferential orientation of the Fe-Al-Ta eutectic alloy at the different solidification rates was studied by Selected Area Electron Diffraction (SAED). Moreover, the lattice misfit between Fe2Ta(Al) Laves phase and Fe(Al,Ta) matrix phase was calculated.

  7. The role of aluminum distribution on the local corrosion resistance of the microstructure in a sand-cast AM50 alloy

    International Nuclear Information System (INIS)

    Danaie, Mohsen; Asmussen, Robert Matthew; Jakupi, Pellumb; Shoesmith, David W.; Botton, Gianluigi A.

    2013-01-01

    Highlights: •Site-specific analytical electron microscopy was performed on corroded AM50. •Areas close to eutectic microstructure show less corrosion damage. •Eutectic Mg grains develop an Al-rich layer between the alloy and corrosion product. •We demonstrate, using low-loss EELS, that the Al-rich layer is metallic in character. •Primary α-Mg grains, with lower Al content, do not develop the Al-rich layer and corrode severely. -- Abstract: Site-specific analytical electron microscopy was performed on a corroded sand-cast AM50 alloy. Areas close to partially divorced eutectic were the regions with less corrosion damage. The corrosion product layer in these areas consisted of a columnar section of predominantly amorphous MgO. At the alloy interface, an aluminum-rich layer was identified. Electron energy-loss spectroscopy suggests this layer is metallic in character. The corrosion product film on the primary α-Mg grains possessed a bi-layer morphology: a thin columnar film and a thicker, porous sub-layer. The formation of the Al-rich layer depends on the Al content in solid solution at a specific location

  8. Pb induces superconductivity in Bi2Se3 analyzed by point contact spectroscopy

    OpenAIRE

    Arevalo-López, P.; López-Romero, R. E.; Escudero, R.

    2015-01-01

    Some topological insulators become superconducting when doped with Cu and Pd. Superconductivity in a non-superconductor may be induced by proximity effect: i.e. Contacting a non-superconductor with a superconductor. The superconducting macroscopic wave function will induce electronic pairing into the normal compound. In the simplest topological insulator, Bi$_2$Se$_3$, superconductivity may be induced with Pb. We studied with point contact junctions formed by contacting Bi$_2$Se$_3$ crystals ...

  9. Determination of the neutron resonance parameters for 206Pb and of the thermal neutron capture cross section for 206Pb and 209Bi

    International Nuclear Information System (INIS)

    Borella, A.

    2005-01-01

    Chapter 1 describes the motivation of the measurements (accelerator driven systems, stellar nucleosynthesis, neutron induced reactions on 206 Pb), the present status of the neutron capture data for 206 Pb and 209 Bi and the structure of this work. In Chapter 2 the basic reaction theory underlying this work is described. The neutron induced reaction mechanism and formalism are explained. The parameterisation of the cross section in terms of R-matrix theory is discussed and we put particular emphasis on the statistical behaviour of the resonance parameters and the impact of the angular distribution of gamma rays following neutron capture. The relation between experimental observables and the resonance parameters is discussed together with general comments related to resonance shape analysis. Chapter 3 is focused on the determination of resonance parameters for 206 Pb. We performed high-resolution transmission and capture measurements at the Time-Of-Flight (TOF) facility GELINA of the IRMM at Geel (B) and determined the resonance parameters. For nuclei like 206 Pb, where the total width is dominated by Γ n , the capture area allows to determine G . Transmission measurements were carried out to determine Γ n , and the statistical factor g of resonances. Before performing a Resonance Shape Analysis (RSA) on the transmission and capture data, we verified the neutron flux and resolution at GELINA. We also compared the characteristics of GELINA with those of the n-TOF facility at CERN. A special emphasis is placed on the total energy detection technique using C 6 D 6 detectors. This technique was applied for the determination of the capture cross section. To reduce systematic bias effects on the capture cross section, the response of the detectors was determined by Monte Carlo simulations, which has been validated by experiments. Using these response functions the partial capture cross sections for individual resonances of 206 Pb have been deduced, by unfolding the

  10. Structure of the liquid-vapor interface of a dilute ternary alloy: Pb and In in Ga

    International Nuclear Information System (INIS)

    Yang Bin; Li Dongxu; Rice, Stuart A.

    2003-01-01

    We report the results of experimental studies of how the competition between two solutes to segregate in the liquid-vapor interface of a dilute ternary alloy influences the composition and structure of that interface. The system studied has small amounts of Pb and In dissolved in Ga; it differs from a previous study of dilute alloys containing small amounts of Pb and Sn dissolved in Ga by the addition of a new variable, namely, the valence difference between the solute atoms Pb and In. This valence difference influences the electron density distribution in the alloy liquid-vapor interface in proportion to the excess concentrations of the solute species in the interface, and thereby should affect the structure of the interface. We find that for a ternary PbInGa alloy that contains 0.039 at. % Pb and 6.31 at. % In, the Pb that segregates in the liquid-vapor interface forms a two-dimensional hexagonal crystal phase that undergoes a first-order transition to a disordered phase at T=29.0±0.1 deg. C. The two-dimensional crystalline Pb forms about 0.6 of a full monolayer; the remainder of the outer stratum of the liquid-vapor interface is filled with two-dimensional liquid In. For a ternary PbInGa alloy that contains the same amount of Pb and 12.2 at. % In, the Pb that segregates in the liquid-vapor interface forms a two-dimensional liquid down to 26.0 deg. C, the lowest temperature at which data were taken. For temperatures in excess of 29.0 deg. C two-dimensional liquid Pb and two-dimensional liquid In coexist in the interface, with the fractional occupation of the monolayer by In exceeding the fractional occupation by Pb

  11. Phase Equilibria of the Ternary Sn-Pb-Co System at 250°C and Interfacial Reactions of Co with Sn-Pb Alloys

    Science.gov (United States)

    Wang, Chao-hong; Kuo, Chun-yi; Yang, Nian-cih

    2015-11-01

    The isothermal section of the ternary Sn-Pb-Co system at 250°C was experimentally determined through a series of the equilibrated Sn-Pb-Co alloys of various compositions. The equilibrium phases were identified on the basis of compositional analysis. For the Sn-Co intermetallic compounds (IMCs), CoSn3, CoSn2, CoSn and Co3Sn2, the Pb solubility was very limited. There exist five tie-triangle regions. The Co-Pb system involves one monotectic reaction, so the phase separation of liquid alloys near the Co-Pb side occurred prior to solidification. The immiscibility field was also determined. Additionally, interfacial reactions between Co and Sn-Pb alloys were conducted. The reaction phase for the Sn-48 at.%Pb and Sn-58 at.%Pb at 250°C was CoSn3 and CoSn2, respectively. Both of them were simultaneously formed in the Sn-53 at.%Pb/Co. The formed IMCs were closely associated to the phase equilibria relationship of the liquid-CoSn3-CoSn2 tie-triangle. Furthermore, with increasing temperatures, the phase formed in equilibrium with Sn-37 wt.%Pb was found to transit from CoSn3 to CoSn2 at 275°C. We propose a simple method of examining the phase transition temperature in the interfacial reactions to determine the boundaries of the liquid-CoSn3-CoSn2 tie-triangles at different temperatures.

  12. Development of Pb-Free Nanocomposite Solder Alloys

    Directory of Open Access Journals (Sweden)

    Animesh K. Basak

    2018-04-01

    Full Text Available As an alternative to conventional Pb-containing solder material, Sn–Ag–Cu (SAC based alloys are at the forefront despite limitations associated with relatively poor strength and coarsening of grains/intermetallic compounds (IMCs during aging/reflow. Accordingly, this study examines the improvement of properties of SAC alloys by incorporating nanoparticles in it. Two different types of nanoparticles were added in monolithic SAC alloy: (1 Al2O3 or (2 Fe and their effect on microstructure and thermal properties were investigated. Addition of Fe nanoparticles leads to the formation of FeSn2 IMCs alongside Ag3Sn and Cu6Sn5 from monolithic SAC alloy. Addition of Al2O3 nano-particles do not contribute to phase formation, however, remains dispersed along primary β-Sn grain boundaries and act as a grain refiner. As the addition of either Fe or Al2O3 nano-particles do not make any significant effect on thermal behavior, these reinforced nanocomposites are foreseen to provide better mechanical characteristics with respect to conventional monolithic SAC solder alloys.

  13. Aging and its circumvention in rf-plasma oxidized Pb-alloy Josephson junctions

    International Nuclear Information System (INIS)

    Wada, M.; Nakano, J.

    1987-01-01

    The aging phenomenon of Pb-alloy Josephson junctions is investigated and an effective method of circumventing it is presented. Junctions consist of Pb-alloy electrodes and a tunneling barrier formed by rf-plasma oxidation of the Pb-alloy. First, aging and annealing-driven change in normal tunneling resistance are compared to verify the usage of annealing as an experimental method for simulation and acceleration of aging. Next, process variables affecting the annealing change in junction characteristics are examined and their influence is described. The importance of the oxide-base electrode interface is confirmed and that of the counterelectrode-oxide interface is experimentally shown. Furthermore, possible changes in the oxide itself are discussed. Finally, on the basis of these studies, rf-plasma oxidation in a CO 2 atmosphere is employed and proven to be an effective method for circumventing the annealing change in the junction characteristics

  14. Study of the influence of gravity on the thermodynamic equilibrium of a liquid alloy, and on its solidification: application to eutectic Al-Ge and monotectic Al-In alloys

    International Nuclear Information System (INIS)

    Vinet, Bernard

    1981-01-01

    After having recalled the meaning of gravity, this research thesis addresses the study of movements within the Earth gravity field to assess accelerations for a centrifuged system, and to describe conditions which create weightlessness. The various actions of gravity on fluid phases are analysed by highlighting phenomena of convection and segregation. In a second part, the author addresses the issue of local order. The third part addresses the influence of gravity conditions on the distribution of components of a binary liquid alloy in thermodynamic equilibrium. The fourth part addresses experimental means. The next parts address the eutectic Al-Ge alloy and the monotectic Al-In alloy. Results obtained for liquid alloy are presented, and the author analyse segregations which appeared during solidification in gravity conditions between 40 and 100 g. The influence of these conditions of the structure of both alloys is then studied

  15. Improved ferroelectric and pyroelectric properties of Pb-doped SrBi4Ti4O15 ceramics for high temperature applications

    International Nuclear Information System (INIS)

    Venkata Ramana, E.; Graça, M.P.F.; Valente, M.A.; Bhima Sankaram, T.

    2014-01-01

    Highlights: • Sr 1−x Pb x Bi 4 Ti 4 O 15 (SPBT, x = 0 − 0.4) ceramics were synthesized by soft chemical method. • X-ray diffraction analysis confirmed the formation of bismuth layered structure. • SEM images showed plate like grain morphology with random orientation of plate faces. • Pb-doping resulted in improved ferroelectricity of SrBi 4 Ti 4 O 15 ceramics. • Pb-doped SrBi 4 Ti 4 O 15 exhibited improved pyroelectric properties with high T C . -- Abstract: Ferroelectric properties of Pb-modified strontium bismuth titanate ceramics with chemical formula Sr 1−x Pb x Bi 4 Ti 4 O 15 (x = 0–0.4) were investigated. Polycrystalline ceramics were synthesized by soft chemical method to study the effect of Pb-doping on its physical properties. X-ray diffraction analysis revealed a bismuth layered structure for all the compounds. The doping resulted in an increased tetragonal strain and improved ferroelectric properties. Scanning electron microscope images showed plate like grain morphology with random orientation of platelets. The ferroelectric transition temperature of the ceramics increased systematically from 525 °C to 560 °C with the increase of doping concentration. The piezoelectric coefficient (d 33 ) of the ceramics was enhanced significantly with Pb doping, exhibiting a maximum value of 21.8 pC/N for 40 mol.% Pb-doped SBT. Pyroelectric studies carried out using the Byer–Roundy method indicated that the modified SBT ceramics are promising candidates for high temperature pyroelectric applications

  16. The crystal structure of kudriavite, (Cd,Pb)Bi2S4

    DEFF Research Database (Denmark)

    Balic Zunic, Tonci; Makovicky, Emil

    2007-01-01

    The crystal structure of kudriavite, (Cd,Pb)Bi2S4, a new mineral species, was solved from single-crystal X-ray-diffraction data and refi ned to R = 4.9% (4.3% for a model with split mixed-cation sites). Lattice parameters are a 13.095(1), b 4.0032(3), c 14.711(1) Å, 115.59(1)°, V 695.6(1) Å3....... The structure is equivalent to that of synthetic CdBi2S4, space group C2/m, Z = 4, and represents a pavonite homologue, N = 3. It is built of three-octahedron-thick columns of (311)PbS-like slabs combined by "unitcell twinning" in a quasi-mirror-glide succession. The slabs, which are intrinsically of the same...... topology, differ in the coordination state of bordering cations because of the relative positions of the adjacent layers. In the slabs of type I (the "non-accreting" slab common to all pavonite homologues), the central columns of octahedra are fl anked by half-octahedral (square-pyramidal) coordinations...

  17. Applicability of Al-powder-alloy coating to corrosion barriers of 316SS in liquid lead-bismuth eutectic

    International Nuclear Information System (INIS)

    Kurata, Yuji; Sato, Hidetomo; Yokota, Hitoshi; Suzuki, Tetsuya

    2011-01-01

    A new Al-alloy coating method using Al, Ti and Fe powders has been applied to 316SS in order to develop corrosion resistant coating in liquid lead-bismuth eutectic (LBE). The 316SS plates with coating layers of different Al concentrations were exposed to liquid LBE with controlled oxygen concentrations of 10 -6 to 10 -4 mass% at 823 K for 3600 ks. While surface oxidation and grain boundary corrosion accompanied by liquid LBE penetration are observed in 316SS without Al-alloy coating, the Al-alloy coating is effective to protect such severe corrosion attacks in liquid LBE. Although the coating layer containing 2.8 mass% Al does not always keep sufficient corrosion resistance, good corrosion resistance is obtained through the Al-oxide film formed in liquid LBE in the coating layer where the average Al concentration is 4.2 mass%. Cracks are formed in the coating layer containing 17.8 mass% Al during the coating process. The Al-powder-alloy coating applied to 316SS is promising as a corrosion resistant coating method in liquid LBE environment. (author)

  18. Structure of molten Bi-Sb-alloys by means of neutron diffraction

    International Nuclear Information System (INIS)

    Lamparter, P.; Knoll, W.; Steeb, S.

    1976-01-01

    The structural investigations with melts can be subdivided into two groups: The first group contains molten metals and molten alloys, and one can state that the structure of molten metals and of molten alloys nowadays is rather well understood. Interference functions of molten metals may be described by a hard sphere model. This is valid also for molten alloys with statistical distribution. For the second group, namely molten non-metals and molecular melts, the interference functions as well as the pair correlation functions are very offen rather complicated and not well understood. The present study is concerned with the transition region between these two groups. It is shown that the melts of the Bi-Sb system exhibit a change from metallic to non-metallic structure. Regarding the experimental details: the experiments were done with the two-axes spectrometer D 4 at the high-flux reactor at Grenoble. The containers consisted of cylindrical quartz tubes with a wall thickness of 0.1 cm. The furnace consisted of a direct-heated vanadium tube. The wavelength of the neutrons was 0.695 A. The final result is that the structure in molten Bi-Sb-alloys consists of primitive tetrahedra with coordination number 3. There are less tetrahedra in molten Bi than in molten Sb. Also with rising temperature the number of tetrahedra decreases. It is shown how to compose the coordination numbers of two structures to get the observed coordination number. The observed values are always the mean values of the two structures. (orig./HK) [de

  19. The dispersive optical model for n + [sup 208]Pb and n + [sup 209]Bi

    Energy Technology Data Exchange (ETDEWEB)

    Walter, R.L. (Dept. of Physics, Duke Univ., Durham, NC (United States) Triangle Univ. Nuclear Lab., Durham, NC (United States)); Weisel, G.J. (Dept. of Physics, Duke Univ., Durham, NC (United States) Triangle Univ. Nuclear Lab., Durham, NC (United States)); Das, R.K. (Dept. of Physics, Duke Univ., Durham, NC (United States) Triangle Univ. Nuclear Lab., Durham, NC (United States)); Tornow, W. (Dept. of Physics, Duke Univ., Durham, NC (United States) Triangle Univ. Nuclear Lab., Durham, NC (United States)); Howell, C.R. (Dept. of Physics, Duke Univ., Durham, NC (United States) Triangle Univ. Nuclear Lab., Durham, NC (United States))

    1993-06-01

    The dispersive optical model (DOM) provides a natural connection between the shell model potential for bound states and the optical model for nucleon scattering at positive energies. At TUNL we have developed DOMs for neutron scattering for ten nuclei between [sup 27]Al and [sup 209]Bi. In these studies we rely on TUNL measurements of differential cross-section ([sigma]([theta])) and analyzing power, as well as a wealth of [sigma]([theta]) and total cross section measurements from numerous other laboratories. In this paper we briefly outline the DOM method and the achievements in describing scattering data for n + [sup 208]Pb and n + [sup 209]Bi and single-particle bound-state data for neutrons in [sup 208]Pb. (orig.)

  20. Bandgap Engineering of Lead-Free Double Perovskite Cs2 AgBiBr6 through Trivalent Metal Alloying.

    Science.gov (United States)

    Du, Ke-Zhao; Meng, Weiwei; Wang, Xiaoming; Yan, Yanfa; Mitzi, David B

    2017-07-03

    The double perovskite family, A 2 M I M III X 6 , is a promising route to overcome the lead toxicity issue confronting the current photovoltaic (PV) standout, CH 3 NH 3 PbI 3 . Given the generally large indirect band gap within most known double perovskites, band-gap engineering provides an important approach for targeting outstanding PV performance within this family. Using Cs 2 AgBiBr 6 as host, band-gap engineering through alloying of In III /Sb III has been demonstrated in the current work. Cs 2 Ag(Bi 1-x M x )Br 6 (M=In, Sb) accommodates up to 75 % In III with increased band gap, and up to 37.5 % Sb III with reduced band gap; that is, enabling ca. 0.41 eV band gap modulation through introduction of the two metals, with smallest value of 1.86 eV for Cs 2 Ag(Bi 0.625 Sb 0.375 )Br 6 . Band structure calculations indicate that opposite band gap shift directions associated with Sb/In substitution arise from different atomic configurations for these atoms. Associated photoluminescence and environmental stability of the three-metal systems are also assessed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Study on Exploration of Azeotropic Point of Pb-Sb Alloys by Vacuum Distillation and Ab Initio Molecular Dynamic Simulation

    Science.gov (United States)

    Song, Bingyi; Jiang, Wenlong; Yang, Bin; Chen, Xiumin; Xu, Baoqiang; Kong, Lingxin; Liu, Dachun; Dai, Yongnian

    2016-10-01

    The possibility of the separation of Pb-Sb alloys by vacuum distillation was investigated theoretically. The results show that Pb and Sb can be separated by vacuum distillation. However, the experimental results show that vacuum distillation technique does not provide clear separation. According to the literature, Pb-Sb alloys belong to azeotropic compounds under some certain temperature; the experiment and computer simulation were carried out based on the exceptional condition so as to analyze the reason from the experiment and microstructure of Pb-Sb alloys perspective. The separation of Pb-Sb alloys by vacuum distillation was experimentally carried out to probe the azeotropic point. Also, the functions, such as partial radial distributions functions, the structure factor, mean square displacement, and the density of state, were calculated by ab-initio molecular dynamics for the representation of the structure and properties of Pb-Sb alloys with different composition of Sb. The experimental results indicate that there exists common volatilization for Pb-Sb alloys when Sb content is 16.5 wt pct. On the other hand, the calculation results show that there is an intense interaction between Pb and Sb when Sb content is 22 wt pct, which supports the experimental results although Sb content is slightly deviation.

  2. Surface tension and wetting behaviour of Bi-In-Sn alloys

    International Nuclear Information System (INIS)

    Ervina Efzan Mohd Noor; Ahmad Badri Ismail; Soong, T.K.; Chin, Y.T.; Luay Bakir Hussain

    2007-01-01

    Concerns about possible landfill contamination, influent discharge from production process are one of the reasons convert from lead-containing electronics to lead-free containing. The surface and interfacial properties of Bi-In-Sn lead-free solder system as a basic system of multicomponent alloys proposed as lead-free solder materials have been studied. The surface tension of Bi-In-Sn lead-free solder system of melting temperature 60 degree Celsius has been measured the temperature range 80 degree Celsius and 140 degree Celsius. The study of the wetting behaviour of Bi-In-Sn lead-free solder system on a Cu substrate has been performed by measuring contact angle on various metal substrates by Optical Microscopy with software. (author)

  3. Contactless flowrate sensors for Na, PbBi and Pb flows

    International Nuclear Information System (INIS)

    Buchenau, D.; Gerbeth, G.; Priede, J.

    2011-01-01

    Accurate and reliable flow rate measurements are required for various liquid metal systems such as the Na or Lead-flows in fast reactors, the PbBi-flows in transmutation systems, or the flows in liquid metal targets. For liquid metal flows, a contactless measurement is preferable. In this paper we report on the recent development of two types of such flow meters. The former operates by detecting the flow-induced disturbance in the phase distribution of an externally applied AC magnetic field. Such a phase-shift flow meter was developed with an emitting coil at one side of the duct and two sensing coils at the opposite side. The second approach uses a rotatable single cylindrical permanent magnet, which is placed close to the liquid metal duct. The rotation rate of this magnet is proportional to the flow rate. (author)

  4. Direct synthesis of BiCuChO-type oxychalcogenides by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Pele, Vincent; Barreteau, Celine [Institut de Chimie Moléculaire et des Matériaux d’Orsay, Univ. Paris-Sud, UMR 8182, Orsay F-91405 (France); CNRS, Orsay F-91405 (France); Berardan, David, E-mail: david.berardan@u-psud.fr [Institut de Chimie Moléculaire et des Matériaux d’Orsay, Univ. Paris-Sud, UMR 8182, Orsay F-91405 (France); CNRS, Orsay F-91405 (France); Zhao, Lidong; Dragoe, Nita [Institut de Chimie Moléculaire et des Matériaux d’Orsay, Univ. Paris-Sud, UMR 8182, Orsay F-91405 (France); CNRS, Orsay F-91405 (France)

    2013-07-15

    We report on the direct synthesis of BiCuChO based materials by mechanical alloying (Ch=Se, Te). We show that contrary to the synthesis paths used in the previous reports dealing with this family of materials, which use costly annealings in closed silica tubes under controlled atmosphere, this new synthesis route enables the synthesis of pure phase materials at room temperature under air, with reasonable milling time. This synthesis procedure is easily scalable for large scale applications. - Highlights: • Phase pure BiCuSeO doped and undoped prepared by mechanical alloying. • Synthesis performed under air at room temperature. • Electrical properties similar to that of samples synthesized by a classical path.

  5. Diffusion barrier characteristics and shear fracture behaviors of eutectic PbSn solder/electroless Co(W,P) samples

    International Nuclear Information System (INIS)

    Pan, Hung-Chun; Hsieh, Tsung-Eong

    2012-01-01

    Highlights: ► Diffusion barrier features, activation energies of IMC growth and mechanical behaviors of electroless Co(W,P)/PbSn joints. ► Amorphous Co(W,P) is a sacrificial- plus stuffed-type barrier while polycrystalline Co(W,P) is a sacrificial-type barrier. ► Ductile mode dominates the failure of Co(W,P)/PbSn joints. ► Phosphorus content of Co(W,P) is crucial to the barrier capability and microstructure evolution at Co(W,P)/PbSn interface. ► Diffusion barrier capability is governed by the nature of chemical bonds, rather than the crystallinity of materials. - Abstract: Diffusion barrier characteristics, activation energy (E a ) of IMC growth and bonding properties of amorphous and polycrystalline electroless Co(W,P) (termed as α-Co(W,P) and poly-Co(W,P)) to eutectic PbSn solder are presented. Intermetallic compound (IMC) spallation and an nano-crystalline P-rich layer were observed in PbSn/α-Co(W,P) samples subjected to liquid-state aging at 250 °C. In contrast, IMCs resided on the P-rich layer in PbSn/α-Co(W,P) samples subjected to solid-state aging at 150 °C. Thick IMCs neighboring to an amorphous W-rich layer was seen in PbSn/poly-Co(W,P) samples regardless of the aging type. α-Co(W,P) was found to be a sacrificial- plus stuffed-type barrier while poly-Co(W,P) is mainly a sacrificial-type barrier. The values of E a 's for PbSn/α-Co(W,P) and PbSn/poly-Co(W,P) systems were 338.6 and 167.5 kJ/mol, respectively. Shear test revealed the ductile mode dominates the failure in both α- and poly-Co(W,P) samples. Analytical results indicated the high P content in electroless layer might enhance the barrier capability but degrade the bonding strength.

  6. Observations and insights into Pb-assisted stress corrosion cracking of alloy 600 steam generator tubes

    International Nuclear Information System (INIS)

    Thomas, L.; Bruemmer, Stephen M.

    2005-01-01

    Pb-assisted stress-corrosion cracking (PbSCC) of Alloy 600 steam-generator tubing in high-temperature-water service and laboratory tests were studied by analytical transmission electron microscopy of cross-sectioned samples. Examinations of pulled tubes from many pressurized water reactors revealed lead in cracks from 11 of 17 samples. Comparisons of the degraded intergranular structures with ones produced in simple laboratory tests with PbO in near-neutral AVT water showed that the PbSCC characteristics in service tubing could be reproduced without complex chemistries and heat-flow conditions that can occur during plant operation. Observations of intergranular and transgranular cracks promoted by Pb in the test samples also provided new insights into the mechanisms of PbSCC in mill-annealed and thermally treated Alloy 600

  7. Growth and Morphology of Rod Eutectics

    Energy Technology Data Exchange (ETDEWEB)

    Jing Teng; Shan Liu; R. Trivedi

    2008-03-17

    The formation of rod eutectic microstructure is investigated systematically in a succinonitrile-camphor alloy of eutectic composition by using the directional solidification technique. A new rod eutectic configuration is observed in which the rods form with elliptical cylindrical shape. Two different orientations of the ellipse are observed that differ by a 90{sup o} rotation such that the major and the minor axes are interchanged. Critical experiments in thin samples, where a single layer of rods forms, show that the spacing and orientation of the elliptic rods are governed by the growth rate and the sample thickness. In thicker samples, multi layers of rods form with circular cross-section and the scaling law between the spacing and velocity predicted by the Jackson and Hunt model is validated. A theoretical model is developed for a two-dimensional array of elliptical rods that are arranged in a hexagonal or a square array, and the results are shown to be consistent with the experimental observations. The model of elliptic rods is also shown to reduce to that for the circular rod eutectic when the lengths of the two axes are equal, and to the lamellar eutectic model when one of the axes is much larger than the other one.

  8. Effect of Fe, Ni, and Cr on the corrosion behaviour of hyper-eutectic Al-Si automotive alloy under different pH conditions

    Directory of Open Access Journals (Sweden)

    Mohammad Salim Kaiser

    2018-05-01

    Full Text Available Effect of Fe, Ni and Cr on the corrosion behaviour of hyper-eutectic Al-Si automotive alloy was studied. The test of corrosion behaviour at different environmental pH 1, 3, 5, 7, 9, 11 and 13 was performed using conventional gravimetric measurements and complemented by resistivity, optical micrograph, scanning electron microscopy (SEM and X-ray analyser (EDX investigations. The highest corrosion rate was observed at pH 13 followed by pH 1, while in the pH range of 3.0 to 11, there is a high protection of surface due to formation of stable surface oxide film. The highest corrosion rate at pH 13 is due to presence of sodium hydroxide in the solution in which the surface oxide film is soluble. At pH 1, however, high corrosion rate can be attributed to dissolution of Al due to the surface attack by aggressive chloride ions. Presence of Fe, Ni and Cr in hyper-eutectic Al-Si automotive alloy has significant effect on the corrosion rate at both environmental pH values. Resistivity of alloy surfaces initially decreases at pH 1 and pH 13 due to formation of thin films. The SEM images of corroded samples immersed in pH 1 solution clearly show pores due to uniform degradation of the alloy. In pH 13 solution, however, the corrosion layer looks more packed and impermeable.

  9. Comparative study for axial and radial shuffling scheme effect on the performance of Pb-Bi cooled fast reactors with natural uranium as fuel cycle input

    International Nuclear Information System (INIS)

    Zaki Suud; Indah Rosidah; Maryam Afifah; Ferhat Aziz; Sekimoto, H.

    2013-01-01

    Full text:Comparative study for the Design of Pb-Bi cooled fast reactors with natural uranium as fuel cycle input using special radial shuffling strategy and axial direction modified CANDLE burn-up scheme has been performed. The reactors utilizes UN-PuN as fuel, Eutectic Pb-Bi as coolant, and can be operated without refueling for 10 years in each batch. Reactor design optimization is performed to utilize natural uranium as fuel cycle input. This reactor subdivided into 6-10 regions with equal volume in radial directions. The natural uranium is initially put in region 1, and after one cycle of 10 years of burn-up it is shifted to region 2 and the region 1 is filled by fresh natural uranium fuel. This concept is basically applied to all regions. The calculation has been done by using SRAC-Citation system code and JENDL-3.2 library. The effective multiplication factor change increases monotonously during 10 years reactor operation time. There is significant power distribution change in the central part of the core during the BOC and the EOC in the radial shuffling system. It is larger than that in the case of modified CANDLE case which use axial direction burning region move. The burn-up level of fuel is slowly grows during the first 15 years but then grow faster in the rest of burn-up history. This pattern is a little bit different from the case of modified CANDLE burn-up scheme in Axial direction in which the slow growing burn-up period is relatively longer almost half of the burn-up history. (author)

  10. Measurement of the mass attenuation coefficients and electron densities for BiPbSrCaCuO superconductor at different energies

    Science.gov (United States)

    Çevik, U.; Baltaş, H.

    2007-03-01

    The mass attenuation coefficients for Bi, Pb, Sr, Ca, Cu metals, Bi2O3, PbO, SrCO3, CaO, CuO compounds and solid-state forms of Bi1.7Pb0.3Sr2Ca2Cu3O10 superconductor were determined at 57.5, 65.2, 77.1, 87.3, 94.6, 122 and 136 keV energies. The samples were irradiated using a 57Co point source emitted 122 and 136 keV γ-ray energies. The X-ray energies were obtained using secondary targets such as Ta, Bi2O3 and (CH3COO)2UO22H2O. The γ- and X-rays were counted by a Si(Li) detector with a resolution of 0.16 keV at 5.9 keV. The effect of absorption edges on electron density, effective atomic numbers and their variation with photon energy in composite superconductor samples was discussed. Obtained values were compared with theoretical values.

  11. Neutron spectrum effects on TRU recycling in Pb-Bi cooled fast reactor core

    International Nuclear Information System (INIS)

    Kim, Yong Nam; Kim, Jong Kyung; Park, Won Seok

    2003-01-01

    This study is intended to evaluate the dependency of TRU recycling characteristics on the neutron spectrum shift in a Pb-Bi cooled core. Considering two Pb-Bi cooled cores with the soft and the hard spectrum, respectively, various characteristics of the recycled core are carefully examined and compared with each other. Assuming very simplified fuel cycle management with the homogeneous and single region fuel loading, the burnup calculations are performed until the recycled core reached to the (quasi-) equilibrium state. The mechanism of TRU recycling toward the equilibrium is analyzed in terms of burnup reactivity and the isotopic compositions of TRU fuel. In the comparative analyses, the difference in the recycling behavior between the two cores is clarified. In addition, the basic safety characteristics of the recycled core are also discussed in terms of the Doppler coefficient, the coolant loss reactivity coefficient, and the effective delayed neutron fraction

  12. Electrochemical corrosion of Pb-1 wt% Sn and Pb-2.5 wt% Sn alloys for lead-acid battery applications

    Energy Technology Data Exchange (ETDEWEB)

    Osorio, Wislei R.; Peixoto, Leandro C.; Garcia, Amauri [Department of Materials Engineering, State University of Campinas - UNICAMP, PO Box 612, 13083-970 Campinas, SP (Brazil)

    2009-12-01

    The aim of this study was to compare the electrochemical corrosion behavior of as-cast Pb-1 wt% Sn and Pb-2.5 wt% Sn alloy samples in a 0.5 M H{sub 2}SO{sub 4} solution at 25 C. A water-cooled unidirectional solidification system was used to obtain the as-cast samples. Electrochemical impedance spectroscopy (EIS) diagrams, potentiodynamic polarization curves and an equivalent circuit analysis were used to evaluate the electrochemical corrosion response. It was found that a coarse cellular array has a better electrochemical corrosion resistance than fine cells. The pre-programming of microstructure cell size of Pb-Sn alloys can be used as an alternative way to produce as-cast components of lead-acid batteries with higher corrosion resistance associated with environmental and economical aspects. (author)

  13. Influence of additives on the microstructure and tensile properties of near-eutectic Al-10.8%Si cast alloy

    International Nuclear Information System (INIS)

    Mohamed, A.M.A.; Samuel, A.M.; Samuel, F.H.; Doty, H.W.

    2009-01-01

    The continuing quest for aluminum castings with enhanced mechanical properties for applications in the automotive industries has intensified the interest in aluminum-silicon alloys. In Al-Si alloys, the properties are influenced by the shape and distribution of the eutectic silicon particles in the matrix, as also by the iron intermetallics and copper phases that occur upon solidification. The detailed microstructure and tensile properties of as-cast and heat-treated new experimental alloy belonging to cast Al-Si near-eutectic alloys have been investigated as a function of Fe, Mn, Cu, and Mg content. Microstructural examination was carried out using optical microscopy, image analysis, and electron probe microanalysis (EPMA), wavelength dispersive spectroscopic (WDS) analysis facilities. Tensile properties upon artificial aging in the temperature range of 155-240 o C for 5 h were also investigated. The results show that the volume fraction of Fe-intermetallics increases as the iron or manganese contents increase. Compact polygonal or star-like particles form when the sludge factor is greater than 2.1. The Al 2 Cu phase was observed to dissolve almost completely during solution heat treatment of all the alloys studied, especially those containing high levels of Mg and Fe, while Al 5 Cu 2 Mg 8 Si 6 , sludge, and α-Fe phases were found to persist after solution heat treatment. The β-Al 5 (Fe,Mn)Si phase dissolved partially in Sr-modified alloys, and its dissolution became more pronounced after solution heat treatment. At 0.5% Mn, the β-Fe phase forms when the Fe content is above 0.75%, causing the tensile properties to decrease drastically. The same results are obtained when the levels of both Fe and Mn are increased beyond 0.75%, because of sludge formation. On the other hand, the tensile properties of the Cu-containing alloys are affected slightly at high levels of Mg as a result of the formation of Al 5 Cu 2 Mg 8 Si 6 which decreases the amount of free Mg

  14. An improved method for the separation of 210Bi and 210Po from 210Pb by using solid-phase extraction disk membranes: environmental applications

    International Nuclear Information System (INIS)

    Marley, N.A.; Gaffney, J.S.; Orlandini, K.A.; Cunningham, M.M.; Drayton, P.J.

    1999-01-01

    An improved method is described for the rapid separation of 210 Bi and 210 Po from the parent radionuclide, 210 Pb, in environmental samples. After the metals were leached from a variety of matrices, they were converted to their anionic chloride complexes by addition of 1 M HCl. These complexes can be separated by solid-phase extraction with disk extraction membranes impregnated with anionic chelating particles. This separation technique takes advantage of the differences in sorption behavior of the chloride complexes to strongly basic anion exchange groups. The extraction membranes can then be counted directly for 210 Bi and 210 Po. If sufficient time is allowed for ingrowth of the daughter, the concentration of the parent 210 Pb in the original sample can be determined from the concentration of 210 Bi. In addition, the ratios of 210 Bi/ 210 Pb and 210 Po/ 210 Pb can be obtained by immediate extraction of 210 Bi followed by ingrowth of 210 Bi for a second determination to establish 210 Pb concentration levels. This can be accomplished easily in order to estimate the residence times of atmospheric aerosols or aqueous colloidal materials. This new technique avoids the time consuming extraction, precipitation, and electroplating procedures used previously and eliminates the experimental errors associated with multiple sample manipulations. (orig.)

  15. Synthesis and structural characterization of a novel Sillén - Aurivillius bismuth oxyhalide, PbBi3VO7.5Cl, and its derivatives

    Science.gov (United States)

    Charkin, Dmitri O.; Plokhikh, Igor V.; Kazakov, Sergey M.; Kalmykov, Stepan N.; Akinfiev, Victor S.; Gorbachev, Anatoly V.; Batuk, Maria; Abakumov, Artem M.; Teterin, Yury A.; Maslakov, Konstantin I.; Teterin, Anton Yu; Ivanov, Kirill E.

    2018-01-01

    A new Sillén - Aurivillius family of layered bismuth oxyhalides has been designed and successfully constructed on the basis of PbBiO2X (X = halogen) synthetic perites and γ-form of Bi2VO5.5 solid electrolyte. This demonstrates, for the first time, the ability of the latter to serve as a building block in construction of mixed-layer structures. The parent compound PbBi3VO7.5-δCl (δ ≤ 0.05) has been investigated by powder XRD, TEM, XPS methods and magnetic susceptibility measurements. An unexpected but important condition for the formation of the mixed-layer structure is partial (ca. 5%) reduction of VV into VIV which probably suppresses competitive formation of apatite-like Pb - Bi vanadates. This reduction also stabilizes the γ polymorphic form of Bi2VO5.5 not only in the intergrowth structure, but in Bi2V1-xMxO5.5-y (M = Nb, Sb) solid solutions.

  16. The Influence of Cr on the Solidification Behavior of Polycrystalline γ(Ni)/ γ'(Ni3Al)- δ(Ni3Nb) Eutectic Ni-Base Superalloys

    Science.gov (United States)

    Xie, Mengtao; Helmink, Randolph; Tin, Sammy

    2012-04-01

    In the current investigation, the effect of Cr on the solidification characteristics and as-cast microstructure of pseudobinary γ- δ eutectic alloys based on a near-eutectic composition (Ni-5.5Al-13.5Nb at. pct) was investigated. It was found that Cr additions promote the formation of a higher volume fraction of γ- δ eutectic microstructure in the interdendritic region. Increasing levels of Cr also triggered morphological changes in the γ- δ eutectic and the formation of γ- γ'- δ ternary eutectic during the last stage of solidification. A detailed characterization of the as-cast alloys also revealed that Cr additions suppressed the liquidus, solidus, and γ' precipitation temperature of these γ/ γ'- δ eutectic alloys. A comparison of the experimental results with thermodynamic calculations using the CompuTherm Pandat database (CompuTherm LLC, Madison, WI) showed qualitative agreement.

  17. The effect of Cu addition and milling contaminations on the microstructure evolution of ball milled Al-Pb alloy during sintering

    International Nuclear Information System (INIS)

    Zhu, M.; Ouyang, L.Z.; Wu, Z.F.; Zeng, M.Q.; Li, Y.Y.; Zou, J.

    2006-01-01

    Al-10 wt.%Pb and Al-10 wt.%Pb-x wt.%Cu (x = 0-7.0) bulk alloys were prepared by sintering the mechanically alloyed powders at various temperatures. The microstructure changes of the as consolidated powders in the course of sintering were analyzed by differential scanning calorimetry, scanning electron microscopy, X-ray diffraction analysis and transmission electron microscopy. It has been found that, with respect to the Al-10 wt.%Pb-x wt.%Cu alloy, CuAl 2 and Cu 9 Al 4 phases formed in the milling process, and the amount of CuAl 2 phase increased while the Cu 9 Al 4 phase disappeared gradually in the sintering process. In both Al-10 wt.%Pb and Al-10 wt.%Pb-x wt.%Cu alloys, the sintering process results in the coarsening of Pb phase and the growth rate of Pb phase fulfills the Lifshitz-Slyozov-Wagner equation even though the size of the Pb phase was in nanometer range. The Pb particle exhibits cuboctahedral morphology and has a cubic to cubic orientation relationship with the Al matrix. The addition of Cu strongly depressed the growth rate of Pb. Contamination induced by milling has apparent influence on the microstructure of the sintered alloys. Al 7 Cu 2 Fe and aluminium oxide phases were identified in the sintered alloys. The cuboctahedral morphology of Pb particles was broken up by the presence of the oxide phase

  18. Solidification with back-diffusion of irregular eutectics

    Directory of Open Access Journals (Sweden)

    M. Trepczyńska-Łent

    2008-10-01

    Full Text Available The definition of the α - parameter back-diffusion has been introduced in the work. The alternative models of solidification were describedtaking into consideration back-diffusion process. The possibility of using those models for eutectic alloys solidification is worthyof interest.

  19. Handbook on Lead-bismuth Eutectic Alloy and Lead Properties, Materials Compatibility, Thermal-hydraulics and Technologies - 2015 Edition

    International Nuclear Information System (INIS)

    Fazio, Concetta; Sobolev, V.P.; Aerts, A.; Gavrilov, S.; Lambrinou, K.; Schuurmans, P.; Gessi, A.; Agostini, P.; Ciampichetti, A.; Martinelli, L.; Gosse, S.; Balbaud-Celerier, F.; Courouau, J.L.; Terlain, A.; Li, N.; Glasbrenner, H.; Neuhausen, J.; Heinitz, S.; Zanini, L.; Dai, Y.; Jolkkonen, M.; Kurata, Y.; Obara, T.; Thiolliere, N.; Martin-Munoz, F.J.; Heinzel, A.; Weisenburger, A.; Mueller, G.; Schumacher, G.; Jianu, A.; Pacio, J.; Marocco, L.; Stieglitz, R.; Wetzel, T.; Daubner, M.; Litfin, K.; Vogt, J.B.; Proriol-Serre, I.; Gorse, D.; Eckert, S.; Stefani, F.; Buchenau, D.; Wondrak, T.; Hwang, I.S.

    2015-01-01

    Heavy liquid metals such as lead or lead-bismuth have been proposed and investigated as coolants for fast reactors since the 1950's. More recently, there has been renewed interest worldwide in the use of these materials to support the development of systems for the transmutation of radioactive waste. Heavy liquid metals are also under evaluation as a reactor core coolant and accelerator-driven system neutron spallation source. Several national and international R and D programmes are ongoing for the development of liquid lead-alloy technology and the design of liquid lead-alloy-cooled reactor systems. In 2007, a first edition of the handbook was published to provide deeper insight into the properties and experimental results in relation to lead and lead-bismuth eutectic technology and to establish a common database. This handbook remains a reference in the field and is a valuable tool for designers and researchers with an interest in heavy liquid metals. The 2015 edition includes updated data resulting from various national and international R and D programmes and contains new experimental data to help understand some important phenomena such as liquid metal embrittlement and turbulent heat transfer in a fuel bundle. The handbook provides an overview of liquid lead and lead-bismuth eutectic properties, materials compatibility and testing issues, key aspects of thermal-hydraulics and existing facilities, as well as perspectives for future R and D. (authors)

  20. GePb Alloy Growth Using Layer Inversion Method

    Science.gov (United States)

    Alahmad, Hakimah; Mosleh, Aboozar; Alher, Murtadha; Banihashemian, Seyedeh Fahimeh; Ghetmiri, Seyed Amir; Al-Kabi, Sattar; Du, Wei; Li, Bauhoa; Yu, Shui-Qing; Naseem, Hameed A.

    2018-04-01

    Germanium-lead films have been investigated as a new direct-bandgap group IV alloy. GePb films were deposited on Si via thermal evaporation of Ge and Pb solid sources using the layer inversion metal-induced crystallization method for comparison with the current laser-induced recrystallization method. Material characterization of the films using x-ray diffraction analysis revealed highly oriented crystallinity and Pb incorporation as high as 13.5% before and 5.2% after annealing. Transmission electron microscopy, scanning electron microscopy, and energy-dispersive x-ray mapping of the samples revealed uniform incorporation of elements and complete layer inversion. Optical characterization of the GePb films by Raman spectroscopy and photoluminescence techniques showed that annealing the samples resulted in higher crystalline quality as well as bandgap reduction. The bandgap reduction from 0.67 eV to 0.547 eV observed for the highest-quality material confirms the achievement of a direct-bandgap material.

  1. GePb Alloy Growth Using Layer Inversion Method

    Science.gov (United States)

    Alahmad, Hakimah; Mosleh, Aboozar; Alher, Murtadha; Banihashemian, Seyedeh Fahimeh; Ghetmiri, Seyed Amir; Al-Kabi, Sattar; Du, Wei; Li, Bauhoa; Yu, Shui-Qing; Naseem, Hameed A.

    2018-07-01

    Germanium-lead films have been investigated as a new direct-bandgap group IV alloy. GePb films were deposited on Si via thermal evaporation of Ge and Pb solid sources using the layer inversion metal-induced crystallization method for comparison with the current laser-induced recrystallization method. Material characterization of the films using x-ray diffraction analysis revealed highly oriented crystallinity and Pb incorporation as high as 13.5% before and 5.2% after annealing. Transmission electron microscopy, scanning electron microscopy, and energy-dispersive x-ray mapping of the samples revealed uniform incorporation of elements and complete layer inversion. Optical characterization of the GePb films by Raman spectroscopy and photoluminescence techniques showed that annealing the samples resulted in higher crystalline quality as well as bandgap reduction. The bandgap reduction from 0.67 eV to 0.547 eV observed for the highest-quality material confirms the achievement of a direct-bandgap material.

  2. Cooling thermal parameters and microstructure features of directionally solidified ternary Sn–Bi–(Cu,Ag) solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Bismarck L., E-mail: bismarck_luiz@yahoo.com.br [Department of Materials Engineering, Federal University of São Carlos, UFSCar, 13565-905 São Carlos, SP (Brazil); Garcia, Amauri [Department of Manufacturing and Materials Engineering, University of Campinas, UNICAMP, 13083-860 Campinas, SP (Brazil); Spinelli, José E. [Department of Materials Engineering, Federal University of São Carlos, UFSCar, 13565-905 São Carlos, SP (Brazil)

    2016-04-15

    Low temperature soldering technology encompasses Sn–Bi based alloys as reference materials for joints since such alloys may be molten at temperatures less than 180 °C. Despite the relatively high strength of these alloys, segregation problems and low ductility are recognized as potential disadvantages. Thus, for low-temperature applications, Bi–Sn eutectic or near-eutectic compositions with or without additions of alloying elements are considered interesting possibilities. In this context, additions of third elements such as Cu and Ag may be an alternative in order to reach sounder solder joints. The length scale of the phases and their proportions are known to be the most important factors affecting the final wear, mechanical and corrosions properties of ternary Sn–Bi–(Cu,Ag) alloys. In spite of this promising outlook, studies emphasizing interrelations of microstructure features and solidification thermal parameters regarding these multicomponent alloys are rare in the literature. In the present investigation Sn–Bi–(Cu,Ag) alloys were directionally solidified (DS) under transient heat flow conditions. A complete characterization is performed including experimental cooling thermal parameters, segregation (XRF), optical and scanning electron microscopies, X-ray diffraction (XRD) and length scale of the microstructural phases. Experimental growth laws relating dendritic spacings to solidification thermal parameters have been proposed with emphasis on the effects of Ag and Cu. The theoretical predictions of the Rappaz-Boettinger model are shown to be slightly above the experimental scatter of secondary dendritic arm spacings for both ternary Sn–Bi–Cu and Sn–Bi–Ag alloys examined. - Highlights: • Dendritic growth prevailed for the ternary Sn–Bi–Cu and Sn–Bi–Ag solder alloys. • Bi precipitates within Sn-rich dendrites were shown to be unevenly distributed. • Morphology and preferential region for the Ag{sub 3}Sn growth depend on Ag

  3. Silumins alloy crystallization

    Directory of Open Access Journals (Sweden)

    S. Pietrowski

    2009-07-01

    Full Text Available This paper presents the results of research, by ATD method, of hypo-, near- and hyperutectic silumins crystallization containing the following alloying additives: Mg, Ni, Cu, Cr, Mo, W, V. It has been shown that, depending on their concentration may crystallize pre-eutectic or eutectic multicomponent phases containing these alloy additives. It has been revealed that any subsequent crystallizable phase nucleate and grows near the liquid/former crystallized phase interface. In multiphases compound also falls the silicon, resulting in a reduction in its quantity and the fragmentation in the eutectic mixture. As a result, it gets a high hardness of silumins in terms of 110-220HB.

  4. High Bismuth Alloys as Lead-Free Alternatives for Interconnects in High-Temperature Electronics

    Science.gov (United States)

    Mallampati, Sandeep

    Predominant high melting point solders for high-temperature electronics (operating temperatures from 200 to 250°C) are Pb-based which are being banned from usage due to their toxic nature. In this study, high bismuth alloy compositions (Bi-14Cu-8Sn, Bi-20Sb-10Cu, Bi-15Sb-10Cu and Bi-10Sb-10Cu) were designed, cast, and characterized to understand their potential as replacements. The desirable aspect of Bi is its high melting temperature, which is 271°C. Alloying elements Sn, Sb and Cu were added to improve some of its properties such as thermal conductivity, plasticity, and reactivity with Cu and Ni surface. Metallographic sectioning and microstructure analysis were performed on the bulk alloys to compare the evolution of phases predicted from equilibrium phase diagrams. Reflow processes were developed to make die-attach samples out of the proposed alloys and die-shear testing was carried out to characterize mechanical integrity of the joint. Thermal shock between -55°C to 200°C and high temperature storage at 200°C were performed on the assembled die-attach samples to study microstructure evolution and mechanical behavior of the reflowed alloys under accelerated testing conditions. In addition, heat dissipation capabilities, using flash diffusivity, were measured on the bulk alloys and also on the die-attach assembly. Finally, tensile testing was performed on the dogbone specimens to identify the potential for plastic deformation and electron backscatter diffraction (EBSD) analysis was used to study the grain orientations on the fracture surfaces and their influence on the crack propagation. Bi-14Cu-8Sn has formed BiNi by on the die backside metallization and the reaction with Cu was poor. This has resulted in weaker substrate side interface. It was observed that Bi-Sb alloys have strong reactivity with Ni (forming Bi3Ni, BiNi and NiSb intermetallic phases), and with Cu (forming Cu2Sb, Cu4Sb). Spallation was observed in NiSb interfacial intermetallic layer and

  5. Thermoelectric power of Bi and Bi{sub 1{minus}x}Sb{sub x} alloy thin films and superlattices grown by MBE

    Energy Technology Data Exchange (ETDEWEB)

    Cho, S; DiVenere, A; Wong, G K; Ketterson, J B; Meyer, J R; Hoffman, C A

    1997-07-01

    The authors have measured the thermoelectric power (TEP) of MBE-grown epitaxial Bi and Bi{sub 1{minus}x} alloy thin films and superlattices as a function of temperature in the range 20--300 K. They have observed that the TEP of a Bi thin film of 1 {micro}m thickness is in good agreement with the bulk single crystal value and that the TEPs for superlattices with 400 {angstrom} and 800 {angstrom} Bi well thicknesses are enhanced over the bulk values. For x = 0.072 and 0.088 in Bi{sub 1{minus}x}Sb{sub x} thin films showing semiconducting behavior, TEP enhancement was observed by a factor of two. However as Bi or Bi{sub 1{minus}x}Sb{sub x} well thickness decreases in superlattice geometry, the TEP decreases, which may be due to unintentional p-type doping.

  6. Bandgap engineering of lead-free double perovskite Cs_2AgBiBr_6 through trivalent metal alloying

    International Nuclear Information System (INIS)

    Du, Ke-zhao; Mitzi, David B.; Meng, Weiwei; Wang, Xiaoming; Yan, Yanfa

    2017-01-01

    The double perovskite family, A_2M"IM"I"I"IX_6, is a promising route to overcome the lead toxicity issue confronting the current photovoltaic (PV) standout, CH_3NH_3PbI_3. Given the generally large indirect band gap within most known double perovskites, band-gap engineering provides an important approach for targeting outstanding PV performance within this family. Using Cs_2AgBiBr_6 as host, band-gap engineering through alloying of In"I"I"I/Sb"I"I"I has been demonstrated in the current work. Cs_2Ag(Bi_1_-_xM_x)Br_6 (M=In, Sb) accommodates up to 75 % In"I"I"I with increased band gap, and up to 37.5 % Sb"I"I"I with reduced band gap; that is, enabling ca. 0.41 eV band gap modulation through introduction of the two metals, with smallest value of 1.86 eV for Cs_2Ag(Bi_0_._6_2_5Sb_0_._3_7_5)Br_6. Band structure calculations indicate that opposite band gap shift directions associated with Sb/In substitution arise from different atomic configurations for these atoms. Associated photoluminescence and environmental stability of the three-metal systems are also assessed. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Influence of convection on eutectic microstructure

    Science.gov (United States)

    Baskaran, V.; Eisa, G. F.; Wilcox, W. R.

    1985-01-01

    When the MnBi-Bi eutectic is directionally solidified, it forms fibers of MnBi in a matrix of bismuth. When the material solidified in space at rates of 30 and 50 cm/hr, the average fiber spacing lambda was about one half of the value obtained in cases in which the same material solidified on earth. Neither an altered temperature gradient nor a fluctuating freezing rate are apparently responsible for the change in lambda, and the possibility is studied that natural convection increases lambda on earth by perturbing the compositional field in the melt ahead of the growing solid. A theoretical analysis is conducted along with some experiments. On the basis of the theoretical results for lamellar growth, it is concluded that the spacing lambda increases with increasing stirring, especially at small freezing rates. The experiments indicate that at low growth rates the cross-sectional area of the MnBi blades increases with increased stirring and with decreased growth rate.

  8. Effect of length scale on mechanical properties of Al-Cu eutectic alloy

    Science.gov (United States)

    Tiwary, C. S.; Roy Mahapatra, D.; Chattopadhyay, K.

    2012-10-01

    This paper attempts a quantitative understanding of the effect of length scale on two phase eutectic structure. We first develop a model that considers both the elastic and plastic properties of the interface. Using Al-Al2Cu lamellar eutectic as model system, the parameters of the model were experimentally determined using indentation technique. The model is further validated using the results of bulk compression testing of the eutectics having different length scales.

  9. Influence of conditions of preparation on quality of superconductors Bi(Pb)SrCaCuO with boron

    International Nuclear Information System (INIS)

    Sykorova, D.; Smrckova, O.; Ptrydes, D.; Vasek, P.

    1999-01-01

    The aim of this work was to verify influence of B 2 O 3 on formation of the phase Bi-2223 of samples with nominal composition Bi 1.8 (Pb 0.26 )Sr 2 Ca 2 Cu 3 O 8+x . Conditions of preparation of superconductors as well as their properties are described

  10. Superconducting alloys

    International Nuclear Information System (INIS)

    Bowers, J.E.

    1976-01-01

    Reference is made to superconductors having high critical currents. The superconductor described comprises an alloy consisting of a matrix of a Type II superconductor which is a homogeneous mixture of 50 to 95 at.% Pb and 5 to 40 at.%Bi and/or 10 to 50 at.%In. Dispersed in the matrix is a material to provide pinning centres comprising from 0.01% to 20% by volume of the alloy; this material is a stable discontinuous phase of discrete crystalline particles of Cu, Mn, Te, Se, Ni, Ca, Cr, Ce, Ge or La, either in the form of the element or a compound with a component of the matrix. These particles should have an average diameter of not more than 2μ. A method for making this alloy is described. (U.K.)

  11. Study of Bi-2212 phase doped Sn(Pb) by means of pat

    International Nuclear Information System (INIS)

    Ma Qingzhu; Huang Xiaoqian; Xiong Xiaotao

    1997-01-01

    Investigation on the effect of Sn/Pb-doped Bi-2212 superconductors has been carried out by the simultaneous measurements of the spectra of positron annihilation lifetime and positron Doppler broadening, together with X-ray diffraction. The results of samples with different doping level show the occupation of Sn atoms on Bi sites. At weak doping level, Sn doping results in a enhancement of cooperation between layers and increment of superconducting transition temperature. At the strong doping level, Sn atoms occupy the sites of Cu-O layers, and at the same time, the other nonsuperconducting phases appear, which results in a decline of the superconducting transition temperature

  12. Measurements of neutron-induced fission cross sections of Pb and Bi at intermediate energies

    International Nuclear Information System (INIS)

    Ryzhov, Igor; Tutin, Gennady; Eismont, Vilen; Mitryukhin, Andrey; Oplavin, Valery; Soloviev, Sergey; Conde, Henri; Olsson, Nils; Renberg, Per-Ulf

    2002-01-01

    Neutron-induced fission cross sections of nat Pb and 209 Bi have been measured relative to the 238 U(n.f) cross section at energies 96 MeV for lead and 133 MeV for bismuth. The measurements were performed at the quasi-mono-energetic neutron beam facility of The Svedberg Laboratory in Uppsala using Frisch-gridded ionization chamber. The results obtained are compared with other experimental data. The present state of the Bi standard recommended by IAEA is discussed. (author)

  13. The excess enthalpies of liquid Ge-Pb-Te alloys

    International Nuclear Information System (INIS)

    Blachnik, R.; Binder, J.; Schlieper, A.

    1997-01-01

    The excess enthalpies of liquid alloys in the ternary system Ge-Pb-Te were determined at 1210 K in a heat flow calorimeter for five sections Ge y Pb 1-y -Te with y = 0.2, 0.4, 0.5, 0.6 and 0.8 and at 1153 K for Ge 0.5 Pb 0.5 -Te. The enthalpy surface in the ternary system is determined by a valley of exothermic minima, stretching from an exothermic minimum at the composition GeTe to one at the composition PbTe in the respective binaries. The excess enthalpies in the limiting metallic binary were adapted with the Redlich-Kister formalism. For the description of the thermodynamic functions in the ternary system the equation of Bonnier was taken using ternary coefficients. The calculated curves are in good agreement with the experimental data. (orig.)

  14. The glass transition, crystallization and melting in Au-Pb-Sb alloys

    Science.gov (United States)

    Lee, M. C.; Allen, J. L.; Fecht, H. J.; Perepezko, J. H.; Ohsaka, K.

    1988-01-01

    The glass transition, crystallization and melting of Au(55)Pb(22.5)Sb(22.5) alloys have been studied by differential scanning calorimetry DSC. Crystallization on heating above the glass transition temperature Tg (45 C) begins at 64 C. Further crystallization events are observed at 172 C and 205 C. These events were found to correspond to the formation of the intermetallic compounds AuSb2, Au2Pb, and possibly AuPb2, respectively. Isothermal DSC scans of the glassy alloy above Tg were used to monitor the kinetics of crystallization. The solidification behavior and heat capacity in the glass-forming composition range were determined with droplet samples. An undercooling level of 0.3T(L) below the liquidus temperature T(L) was achieved, resulting in crystallization of different stable and metastable phases. The heat capacity C(P) of the undercooled liquid was measured over an undercooling range of 145 C.

  15. Corrosion of stainless steels in lead-bismuth eutectic up to 600 °C

    Science.gov (United States)

    Soler, L.; Martín, F. J.; Hernández, F.; Gómez-Briceño, D.

    2004-11-01

    An experimental program has been carried out to understand the differences in the corrosion behaviour between different stainless steels: the austenitic steels 304L and 316L, the martensitic steels F82Hmod, T91 and EM10, and the low alloy steel P22. The influence of oxygen level in Pb-Bi, temperature and exposure time is studied. At 600 °C, the martensitic steels and the P22 steel exhibit thick oxide scales that grow with time, following a linear law for the wet environment and a parabolic law for the dry one. The austenitic stainless steels show a better corrosion behaviour, especially AISI 304L. Under reducing conditions, the steels exhibit dissolution, more severe for the austenitic stainless steels. At 450 °C, all the materials show an acceptable behaviour provided a sufficient oxygen level in the Pb-Bi. At reducing conditions, the martensitic steels and the P22 steel have a good corrosion resistance, while the austenitic steels exhibit already dissolution at the longer exposures.

  16. Corrosion of stainless steels in lead-bismuth eutectic up to 600 deg. C

    International Nuclear Information System (INIS)

    Soler, L.; Martin, F.J.; Hernandez, F.; Gomez-Briceno, D.

    2004-01-01

    An experimental program has been carried out to understand the differences in the corrosion behaviour between different stainless steels: the austenitic steels 304L and 316L, the martensitic steels F82Hmod, T91 and EM10, and the low alloy steel P22. The influence of oxygen level in Pb-Bi, temperature and exposure time is studied. At 600 deg. C, the martensitic steels and the P22 steel exhibit thick oxide scales that grow with time, following a linear law for the wet environment and a parabolic law for the dry one. The austenitic stainless steels show a better corrosion behaviour, especially AISI 304L. Under reducing conditions, the steels exhibit dissolution, more severe for the austenitic stainless steels. At 450 deg. C, all the materials show an acceptable behaviour provided a sufficient oxygen level in the Pb-Bi. At reducing conditions, the martensitic steels and the P22 steel have a good corrosion resistance, while the austenitic steels exhibit already dissolution at the longer exposures

  17. Containerless solidification of undercooled oxide and metallic eutectic melts

    International Nuclear Information System (INIS)

    Li Mingjun; Nagashio, Kosuke; Kuribayashi, Kazuhiko

    2004-01-01

    A high-speed video was employed to monitor the in situ recalescence of undercooled oxide Al 2 O 3 -36.8 at.% ZrO 2 and metallic Ni-18.7 at.% Sn eutectics that were processed on an aero-acoustic levitator and an electromagnetic levitator, respectively. For the oxide eutectic, the entire sample becomes brighter and brighter without any clear recalescence front during spontaneous crystallization. When the sample was seeded at desired undercoolings, crystallization started from the seeding point and then spread through the entire sample. Microstructures of the oxide solidified via both the spontaneous crystallization and external seeding consist of many independent eutectic colonies at the sample surface, indicating that copious nucleation takes place regardless of melt undercooling and solidification mode. For the metallic eutectics, two kinds of recalescence are visualized. The surface and cross sectional microstructures reveal that copious nucleation is also responsible for the formation of independent eutectic colonies distributing within the entire sample. It is not possible to measure the growth velocity of a single eutectic colony using optical techniques under the usual magnification. The conventional nucleation concept derived from single-phase alloys may not be applicable to the free solidification of the undercooled double-phase oxide and metallic eutectic systems

  18. Bi-Sn alloy catalyst for simultaneous morphology and doping control of silicon nanowires in radial junction solar cells

    International Nuclear Information System (INIS)

    Yu, Zhongwei; Lu, Jiawen; Qian, Shengyi; Xu, Jun; Xu, Ling; Wang, Junzhuan; Shi, Yi; Chen, Kunji; Misra, Soumyadeep; Roca i Cabarrocas, Pere; Yu, Linwei

    2015-01-01

    Low-melting point metals such as bismuth (Bi) and tin (Sn) are ideal choices for mediating a low temperature growth of silicon nanowires (SiNWs) for radial junction thin film solar cells. The incorporation of Bi catalyst atoms leads to sufficient n-type doping in the SiNWs core that exempts the use of hazardous dopant gases, while an easy morphology control with pure Bi catalyst has never been demonstrated so far. We here propose a Bi-Sn alloy catalyst strategy to achieve both a beneficial catalyst-doping and an ideal SiNW morphology control. In addition to a potential of further growth temperature reduction, we show that the alloy catalyst can remain quite stable during a vapor-liquid-solid growth, while providing still sufficient n-type catalyst-doping to the SiNWs. Radial junction solar cells constructed over the alloy-catalyzed SiNWs have demonstrated a strongly enhanced photocurrent generation, thanks to optimized nanowire morphology, and largely improved performance compared to the reference samples based on the pure Bi or Sn-catalyzed SiNWs

  19. Effect of copper valence on the glass structure and crystallization behavior of Bi-Pb-Cu-O glasses

    International Nuclear Information System (INIS)

    Hu, Yi; Lin, U.-L.; Liu, N.-H.

    1997-01-01

    Bi 0.43 Pb 0.35 Cu 0.22 O y glasses with different Cu + contents were prepared by melting at different temperatures. The glass structure consists of [BiO 3 [ and [BiO 6 [ units and the ratio of [BiO 3 [/[BiO 6 [ increases with increasing Cu + content. The glass transition temperature, the first crystallization temperature peak, and the thermal stability of the glasses decreases with increasing Cu + content. The value of the activation energy, E a , varies as a function of the Cu + content. The crystallization mechanism in the glasses is closely related to the glass structure, which is mainly affected by the Cu + content. (orig.)

  20. Microstructural discovery of Al addition on Sn–0.5Cu-based Pb-free solder design

    International Nuclear Information System (INIS)

    Koo, Jahyun; Lee, Changsoo; Hong, Sung Jea; Kim, Keun-Soo; Lee, Hyuck Mo

    2015-01-01

    It is important to develop Pb-free solder alloys suitable for automotive use instead of traditional Sn–Pb solder due to environmental regulations (e.g., Restriction of Hazardous Substances (RoHS)). Al addition has been spotlighted to enhance solder properties. In this study, we investigated the microstructural change of Sn–0.5Cu wt.% based Pb-free solder alloys with Al addition (0.01–0.05 wt.%). The small amount of Al addition caused a remarkable microstructural change. The Al was favored to form Cu–Al intermetallic compounds inside the solder matrix. We identified the Cu–Al intermetallic compound as Cu_3_3Al_1_7, which has a rhombohedral structure, using EPMA and TEM analyses. This resulted in refined Cu_6Sn_5 networks in the Sn–0.5Cu based solder alloy. In addition, we conducted thermal analysis to confirm its stability at a high temperature of approximately 230 °C, which is the necessary temperature range for automotive applications. The solidification results were substantiated thermodynamically using the Scheil solidification model. We can provide criteria for the minimum aluminum content to modify the microstructure of Pb-free solder alloys. - Graphical abstract: The minor Al additions refined eutectic Cu_6Sn_5 IMC networks on the Sn–0.5Cu based solder alloys. The microstructure was dramatically changed with the minor Al addition. - Highlights: • We observed dramatic microstructure-change with Al additions. • We defined Cu_3_3Al_1_7 IMC with Al additions using TEM analysis. • We investigated grain refinement with Al additions using EBSD. • We discussed the refinement based on Scheil solidification model.

  1. Microstructural discovery of Al addition on Sn–0.5Cu-based Pb-free solder design

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Jahyun; Lee, Changsoo [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of); Hong, Sung Jea [MK Electron Co., Ltd., Yongin Cheoin-gu 316-2 (Korea, Republic of); Kim, Keun-Soo, E-mail: keunsookim@hoseo.edu [Department of Display Engineering, Hoseo University, Asan 336-795 (Korea, Republic of); Lee, Hyuck Mo, E-mail: hmlee@kaist.ac.kr [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of)

    2015-11-25

    It is important to develop Pb-free solder alloys suitable for automotive use instead of traditional Sn–Pb solder due to environmental regulations (e.g., Restriction of Hazardous Substances (RoHS)). Al addition has been spotlighted to enhance solder properties. In this study, we investigated the microstructural change of Sn–0.5Cu wt.% based Pb-free solder alloys with Al addition (0.01–0.05 wt.%). The small amount of Al addition caused a remarkable microstructural change. The Al was favored to form Cu–Al intermetallic compounds inside the solder matrix. We identified the Cu–Al intermetallic compound as Cu{sub 33}Al{sub 17}, which has a rhombohedral structure, using EPMA and TEM analyses. This resulted in refined Cu{sub 6}Sn{sub 5} networks in the Sn–0.5Cu based solder alloy. In addition, we conducted thermal analysis to confirm its stability at a high temperature of approximately 230 °C, which is the necessary temperature range for automotive applications. The solidification results were substantiated thermodynamically using the Scheil solidification model. We can provide criteria for the minimum aluminum content to modify the microstructure of Pb-free solder alloys. - Graphical abstract: The minor Al additions refined eutectic Cu{sub 6}Sn{sub 5} IMC networks on the Sn–0.5Cu based solder alloys. The microstructure was dramatically changed with the minor Al addition. - Highlights: • We observed dramatic microstructure-change with Al additions. • We defined Cu{sub 33}Al{sub 17} IMC with Al additions using TEM analysis. • We investigated grain refinement with Al additions using EBSD. • We discussed the refinement based on Scheil solidification model.

  2. Pionic 4f-3d X-rays from 208Pb and 209Bi

    International Nuclear Information System (INIS)

    Olin, A.; Forsman, J.W.; MacDonald, J.A.; Marshall, G.M.; Numao, T.; Poffenberger, P.R.; Van Esbroek, P.; Kunselman, A.R.; Olaniyi, B.H.

    1985-01-01

    The X-ray energies and widths of the pionic 4f-3d and 5g-4f transitions have been measured in 208 Pb and 209 Bi. The 3d widths obtained are in reasonable agreement with theory, and do not support the anomalously small values previously reported. (orig.)

  3. Magnetic susceptibility measurements on Bi - Sn alloys

    International Nuclear Information System (INIS)

    Mustaffa bin Haji Abdullah

    1985-01-01

    Magnetic susceptibility measurements on eight samples of tin-rich and three samples of bismuth-rich Bi-Sn alloys were made from 85K to 300K by Faraday's method. The susceptibilities of the eight tin-rich samples are positive and greater than the susceptibility of pure tin. The values are approximately constant at low temperatures but decreasing a little bit with increasing temperature. This result is interpreted as due to the predominant contribution of the Pauli spin paramagnetic susceptibility. A small decrease in susceptibility with temperature is interpreted as due to the effect of the second order term in the expression for spin paramagnetic susceptibility. The fluctuation of the susceptibility for alloys of different composition is interpreted as due to the effect of the density of states at the Fermi levels. The three samples of bismuth-rich alloys show a transition to diamagnetic property, where the diamagnetism is increased with temperature. This result is predominant and due to the diamagnetic contribution from the ions. The increase in susceptibility with temperature is interpreted as due to an increase in the effective radii of the ions due to thermal expansion. (author)

  4. Corrosion of ferrous alloys exposed to thermally convective Pb-17 at. % Li

    International Nuclear Information System (INIS)

    Tortorelli, P.F.; DeVan, J.H.

    1986-01-01

    A type 316 stainless steel thermal convection loop with type 316 stainless steel coupons and a Fe-9 Cr-1 Mo steel loop containing Fe-12 Cr-1 MoVW steel specimens circulated molten Pb-17 at. % Li at a maximum temperature of 500 0 C. Specimens were exposed for greater than 6000 h. Mass loss and surface characterization data were compared for these two alloys. At any particular exposure time, the corrosion of type 316 stainless steel by Pb-17 at. % Li was more severe, and of a different type than that of similarly exposed Fe-12 Cr-1 MoVW steel. The austenitic alloy suffered nonuniform penetration and dissolution by the lead-lithium, whereas the Fe-12 Cr-1 MoVW steel tended to be more uniformly corroded. The presence of a ferritic layer on the type 316 stainless steel, and its susceptibility to spalling during specimen cleaning, were shown to be important in evaluating the data and in comparing corrosion losses for the type types of alloys. A model for the nonuniform penetration of type 316 stainless steel by Pb-17 at. % Li was suggested

  5. Effects of Mn addition on microstructure and hardness of Al-12.6Si alloy

    Science.gov (United States)

    Biswas, Prosanta; Patra, Surajit; Mondal, Manas Kumar

    2018-03-01

    In this work, eutectic Al-12.6Si alloy with and without manganese (Mn) have been developed through gravity casting route. The effect of Mn concentration (0.0 wt.%, 1 wt%, 2 wt% and 3 wt%) on microstructural morphology and hardness property of the alloy has been investigated. The eutectic Al-12.6 Si alloy exhibits the presence of combine plate, needle and rod-like eutectic silicon phase with very sharp corners and coarser primary silicon particles within the α-Al phase. In addition of 1wt.% of Mn in the eutectic Al-12.6Si alloy, sharp corners of the primary Si and needle-like eutectic Si are became blunt and particles size is reduced. Further, increase in Mn concentration (2.0 wt.%) in the Al-12.6Si alloy, irregular plate shape Al6(Mn,Fe) intermetallics are formed inside the α-Al phase, but the primary and eutectic phase morphology is similar to the eutectic Al-12.6Si alloy. The volume fraction of Al6(Mn,Fe) increases and Al6(Mn,Fe) particles appear as like chain structure in the alloy with 3 wt.% Mn. An increase in Mn concentration in the Al-12.6Si alloys result in the increase in bulk hardness of the alloy as an effects of microstructure modification as well as the presence of harder Al6(Mn,Fe) phase in the developed alloy.

  6. Evolution of insoluble eutectic Si particles in anodic oxidation films during adipic-sulfuric acid anodizing processes of ZL114A aluminum alloys

    Science.gov (United States)

    Hua, Lei; Liu, Jian-hua; Li, Song-mei; Yu, Mei; Wang, Lei; Cui, Yong-xin

    2015-03-01

    The effects of insoluble eutectic Si particles on the growth of anodic oxide films on ZL114A aluminum alloy substrates were investigated by optical microscopy (OM) and scanning electron microscopy (SEM). The anodic oxidation was performed at 25°C and a constant voltage of 15 V in a solution containing 50 g/L sulfuric acid and 10 g/L adipic acid. The thickness of the formed anodic oxidation film was approximately 7.13 μm. The interpore distance and the diameters of the major pores in the porous layer of the film were within the approximate ranges of 10-20 nm and 5-10 nm, respectively. Insoluble eutectic Si particles strongly influenced the morphology of the anodic oxidation films. The anodic oxidation films exhibited minimal defects and a uniform thickness on the ZL114A substrates; in contrast, when the front of the oxide oxidation films encountered eutectic Si particles, defects such as pits and non-uniform thickness were observed, and pits were observed in the films.

  7. Die-cast of a hypo-eutectic AL-SI alloy: influence of injection temperature on microstructure and mechanical properties

    International Nuclear Information System (INIS)

    Santos, Silvano Leal dos; Santos, Sydney Ferreira

    2014-01-01

    Die-casting is widely used for manufacturing light alloy components for automotive industry. Among others, hypo-eutectic Al-Si alloys are currently processed by die-casting. To obtain high quality die-cast components, a better understanding on the correlations between processing parameters, microstructures, and mechanical properties are of utmost importance. In this study, we investigate the effect of injection temperature of liquid metal on the microstructure and mechanical properties of Al-Si alloy EN AC 46000 (DIN designation). The injection temperatures were 579, 589, 643, and 709 deg C. As-cast components had their microstructures analyzed by X-ray diffraction, optical and scanning electron microscopy, and X-ray energy dispersive spectroscopy. The mechanical properties were examined by micro-hardness and tensile tests. It was observed that the ultimate tensile strength slightly increased with the increase of injection temperature. The same trend was observed for micro-hardness. The amount of porosity in the samples varies in a small amount for different injection temperatures. On the other hand, the microstructure of the alloys seems more refined for higher temperatures of injection. This refinement in microstructure might play a major role on the mechanical properties of the Al-Si die-cast alloy. (author)

  8. Effect of micron size Ni particle addition in Sn–8Zn–3Bi lead-free solder alloy on the microstructure, thermal and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Billah, Md. Muktadir; Shorowordi, Kazi Mohammad; Sharif, Ahmed, E-mail: asharif@mme.buet.ac.bd

    2014-02-05

    Highlights: • Ni-added Sn-Zn-Bi were characterized metallographically, thermally and mechanically. • The volume fraction of α-Zn phase increased with both Bi and Ni in Sn-Zn-Bi alloys. • Micron-sized Ni particles reacted with neither Sn nor Zn to form intermetallics. • Better combination of thermal and mechanical properties can be achieved with Ni. -- Abstract: Micron-sized Ni particle-reinforced Sn–8Zn–3Bi composite solders were prepared by mechanically dispersing Ni particles into Sn–8Zn–3Bi alloy and the bulk properties of the composite solder alloy were characterized metallographically, thermally and mechanically. Different percentage of Ni particle viz. 0.25, 0.5 and 1 wt.% were added in the liquid Sn–8Zn–3Bi alloy and then cast into the metal molds. Melting behavior was studied by differential thermal analyzer (DTA). Microstructural investigation was carried out by both optical and scanning electron microscope. Tensile properties were determined using an Instron Universal Testing Machine at a strain rate 3.00 mm/min. The results indicated that the Ni addition increased the melting temperature of Sn–8Zn–3Bi alloy. The addition of Ni was also found to increase the solidification range. In the Sn–8Zn–3Bi alloy, needle-shaped α-Zn phase was found to be uniformly distributed in the β-Sn matrix. However, it was found that the small amount of Ni addition in Sn–8Zn–3Bi alloy refined the Zn needles throughout the matrix. Also an enhanced precipitation of Zn in the structure was observed with the addition of Ni. All these structural changes improved the mechanical properties like tensile strength and hardness of the newly developed quaternary alloy.

  9. The role of bismuth on the microstructure and corrosion behavior of ternary Mg–1.2Ca–xBi alloys for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Tok, H.Y.; Hamzah, E., E-mail: Esah@fkm.utm.my; Bakhsheshi-Rad, H.R.

    2015-08-15

    Highlights: • Secondary phases have a significant effect on corrosion properties of the alloys. • Microstructure of Mg–Ca–xBi was refined significantly after Bi addition. • Addition of 0.5 wt.% Bi to Mg–Ca alloy leads to increase corrosion resistance. • Microstructure analysis showed needle-shaped precipitates at the grain boundaries. - Abstract: In this study the influence of various Bi additions on the microstructure and corrosion behavior of the Mg–1.2Ca–xBi alloys (x = 0.5, 1.5, 3, 5, 12 wt.%) were evaluated by using optical and scanning electron microscopy, immersion and electrochemical tests. Microstructural observations showed that the refinement efficiency became more pronounced with increased Bi amount. Microstructural results of Mg–1.2Ca–xBi (x = 0.5, 1.5, and 3) indicated that the formation of three distinct phases—namely α-Mg, Mg{sub 2}Ca and Mg{sub 3}Bi{sub 2}. However, further addition of Bi to 5 and 12 wt.% leads to evolution of α-Mg, Mg{sub 3}Bi{sub 2}, and Mg{sub 2}Bi{sub 2}Ca phases. The addition of Bi up to 0.5 wt.% enhanced corrosion resistance while further addition from 1.5 to 12 wt.% accelerated the degradation rate because of the emergence of more galvanic coupling between the α-Mg phases and secondary phases. The analyses showed that the Mg–1.2Ca–0.5Bi alloy gives the best corrosion resistance behavior, which makes it ideal for biodegradable medical applications.

  10. Formation of long-period stacking ordered structures in Mg88M5Y7 (M = Ti, Ni and Pb) casting alloys

    International Nuclear Information System (INIS)

    Jin, Qian-Qian; Fang, Can-Feng; Mi, Shao-Bo

    2013-01-01

    Highlights: •Apart from 18R-LPSO, 14H-LPSO structure was determined in the Mg-Ni-Y alloys. •The appearance of twin-related structure in 18R-LPSO structure results from the stacking faults in the stacking sequence of the closely packed planes. •A new (Pb, Mg) 2 Y phase with a body-centered orthorhombic structure was determined in the Mg-Pb-Y alloy. •No LPSO structures were found in the Mg-Pb-Y and Mg-Ti-Y casting alloys. -- Abstract: Formation of long-period stacking ordered (LPSO) structures is investigated in Mg 88 M 5 Y 7 (M = Ti, Ni and Pb) casting alloys by means of electron microscopy and X-ray diffraction. In the Mg 88 Ni 5 Y 7 casting alloy, 14H-LPSO structure is observed in a small amount, which coexists with 18R-LPSO structure. The appearance of stacking faults in 18R-LPSO structure results in twin-related structure in the stacking sequence of the closely packed planes. A new (Pb, Mg) 2 Y phase with a body-centered orthorhombic structure is determined in the Mg 88 Pb 5 Y 7 alloy. No LPSO structures are found in the Mg 88 Pb 5 Y 7 and Mg 88 Ti 5 Y 7 casting alloys. In terms of the atomic radius and heat of mixing, the formation ability of LPSO structure in the present alloys is discussed

  11. Development of Bi-Sb-Te ternary alloy with compositionally graded structure

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, A; Ohta, T

    1997-07-01

    Compositionally graded p-type Bi-Sb-Te thermoelectric material was synthesized by PIES (Pulverized and Intermixed Elements Sintering) method. The materials consisted of three segmented regions of different alloy composition, i.e., y = 0.8/0.825/0.9 in (Bi{sub 2}Te{sub 3}){sub 1{minus}y} (Sb{sub 2}Te{sub 3}){sub y} system. It was found that the electrical power output of the compositionally graded material was larger than that of the best single composition material when the temperature difference was the designed value.

  12. Four-branched compounds coupled Si and iron-rich intermetallics in near eutectic Al-Si alloys

    International Nuclear Information System (INIS)

    Wu, Yuying; Liu, Xiangfa; Jiang, Binggang; Bian, Xiufang

    2007-01-01

    Many four-branched compounds coupled Si and iron-rich intermetallics were observed in near eutectic Al-Si alloy modified with Al-P master alloy. Such four-branched compounds have never been reported before, but in our case it seems to be commonly observed. In this work the growth characterization of the four-branched compounds are scrutinized with a JXA-8800 electron microprobe (EPMA). More deep study of the formation of four-branched compounds is performed by SEM and TEM analysis. The characterization of the four-branched compounds is that of a primary silicon in the center with four iron-rich intermetallics around. Experimental results also show that the precipitation of primary silicon is the key factor for the formation of four-branched compounds. And WHS-theory explains the growth mechanism of the four-branched compounds. In detail, subsequent twinning within the primary silicon provides four-fold coordination sites on the surface, and then the α-Al(Fe,Mn)-Si phase nucleates on the surface of the primary silicon

  13. Dynamic Analysis of Recalescence Process and Interface Growth of Eutectic Fe82B17Si1 Alloy

    Science.gov (United States)

    Fan, Y.; Liu, A. M.; Chen, Z.; Li, P. Z.; Zhang, C. H.

    2018-03-01

    By employing the glass fluxing technique in combination with cyclical superheating, the microstructural evolution of the undercooled Fe82B17Si1 alloy in the obtained undercooling range was studied. With increase in undercooling, a transition of cooling curves was detected from one recalescence to two recalescences, followed by one recalescence. The two types of cooling curves were fitted by the break equation and the Johnson-Mehl-Avrami-Kolmogorov model. Based on the cooling curves at different undercoolings, the recalescence rate was calculated by the multi-logistic growth model and the Boettinger-Coriel-Trivedi model. Both the recalescence features and the interface growth kinetics of the eutectic Fe82B17Si1 alloy were explored. The fitting results that were obtained using TEM (SAED), SEM and XRD were consistent with the changing rule of microstructures. Finally, the relationship between the microstructure and hardness was also investigated.

  14. Interphase thermodynamic bond in heterogeneous alloys: effects on alloy properties

    International Nuclear Information System (INIS)

    Savchenko, A.M.; Konovalov, Yu.V.; Yuferov, O.I.

    2005-01-01

    Inconsistency between a conventional thermodynamic description of alloys as a mechanical mixture of phases and a real alloys state as a common thermodynamic system in which there is a complicated physical-chemical phases interaction has been considered. It is supposed that in heterogeneous alloys (eutectic ones, for instance), so called interphase thermodynamic bond can become apparent due to a partial electron levels splitting under phase interaction. Thermodynamic description of phase equilibrium in alloys is proposed taking into account a thermodynamic bond for the system with phase diagram of eutectic type, and methods of the value of this bond estimation are presented. Experimental evidence (Al-Cu-Si, Al-Si-Mg-Cu, U-Mo + Al) of the effect of interphase thermodynamic bond on temperature and enthalpy of melting of alloys are produced as well as possibility of its effects on alloys electrical conduction, strength, heat and corrosion resistance is substantiated theoretically [ru

  15. T-x-y diagrams for reciprocal systems PbX + CdI2 = CdX + PbI2 (X=S, Se, Te)

    International Nuclear Information System (INIS)

    Odin, I.N.

    2001-01-01

    The present research is undertaken in search of the new complex phases with interesting physical properties. The synthesized samples was analyzed by differential thermal, X-ray diffraction and microstructural methods. The diagonal cross-section CdTe - PbI 2 of the mutual PbTe + CdI 2 = CdTe + PbI 2 system is stable. The T-x phase diagram of the CdTe - PbI 2 system possess eutectic type, the coordinates of eutectic point is 657 ± 2 K, 15 ± 1 mol. % of CdTe. The lead iodide based solid solutions with the mixed structure and the CdTe based solid solutions take place in the equilibria. Solid CdTe dissolves 0.2 mol. % PbI 2 . The fields of the primary crystallization of the CdTe, Pb 1-x Cd x I 2 , PbTe based solid solutions are on the liquidus surface [ru

  16. Specific heat (1-330K), magnetic susceptiblity and Meissner effect Bi-(Pb)-Sr-Ca-Cu-O samples

    International Nuclear Information System (INIS)

    Junod, A.; Eckert, D.; Triscone, G.; Brunner, O.; Muller, J.; Zhao, Z.

    1989-01-01

    Five samples in the Bi 2 - y Pb y Sr 2 CaCu 2 O 8 + x system selected for their sharp diamagnetic transitions are characterized with particular emphasis on the specific heat. The behavior of the magnetic susceptibility upon doping with holes (Pb) is similar to that of the La 1 - y Sr y CuO 4 system

  17. Enhancement of critical currents in bulk and Ag-sheathed Bi(Pb)-2223 superconductors

    International Nuclear Information System (INIS)

    Brauer, D.J.; Eujen, R.; Hudepohl, J.

    1991-01-01

    This paper reports on the superconducting properties of the Bi(Pb)-2223 phase that have been optimized. Prolonged annealing of coarse powder raised j c in bulk samples to as high as 1100 Acm -2 at 77 K. the temperature dependence was studied between 96 and 4.2 K whereby j c rose gradually from 120 to 2100 Acm -2 . T c dropped from 107 K to 64 K in magnetic fields up to 4 T but decreased by only 1 K/T in higher fields. A tape prepared by rolling and subsequent annealing of Ag tubes containing Bi(Pb)-2223 powder exhibited a j c of 1700 Acm -2 at 77 K and 11000 Acm -2 at 4.2 K. The latter j c dropped to 3000 Acm -2 in a magnetic field of 0.25 t, but it was still 1200 Acm -2 in a 10 T field. A tape fabricated by pressing a drawn and annealed wire proved to be less sensitive to low magnetic fields

  18. A study on the corrosion characteristics of lead-bismuth liquid metal

    International Nuclear Information System (INIS)

    Tak, Nam Il; Park, Won S.; Han, Seok Jung; Jeong, Won Seok

    1999-03-01

    Pb-Bi eutectic has been adopted as a coolant and spallation target material of HYPER (Hybrid Power Extraction Reactor), an accelerator driven subcritical transmutation system. The contents and scope of the present study are to implement systematic survey and analyses of available results on the corrosion characteristics of Pb-Bi liquid metal which are considered to be the most important among Pb-Bi coolant technologies and to provide fundamental bases for future research efforts. Major parameters affecting the corrosion of structural materials in liquid metals are temperature, flow velocity, contents of impurities in coolant, compositions of structural materials, and so forth. It was already known that for traditional commercial austenitic steels of 18Cr-10Ni-Ti type and 12%Cr ferritic steels, the operating temperatures of Pb-Bi coolant cannot be raised above 400 dg C and 450 dg C, respectively. However, extensive researches have been performed to protect structural materials under higher operating temperature such as the development of various kinds of coating methods for steels and the investigations of coolant inhibition by different chemical elements. The available experimental results show that the effective methods to improve the performance of structural materials in Pb-Bi coolant are the development of suitable steel alloys, the creation of oxide type coatings, and the control of oxygen inhibition. According to the recently presented research results of URRS, utilization of these methods makes it possible to raise the operating temperature limit to 620-650 dg C. It provides the possibility of usage of Pb-Bi coolant for the transmutation system, HYPER some day. (Author). 27 refs., 6 tabs., 15 figs

  19. A study on the corrosion characteristics of lead-bismuth liquid metal

    Energy Technology Data Exchange (ETDEWEB)

    Tak, Nam Il; Park, Won S.; Han, Seok Jung; Jeong, Won Seok

    1999-03-01

    Pb-Bi eutectic has been adopted as a coolant and spallation target material of HYPER (Hybrid Power Extraction Reactor), an accelerator driven subcritical transmutation system. The contents and scope of the present study are to implement systematic survey and analyses of available results on the corrosion characteristics of Pb-Bi liquid metal which are considered to be the most important among Pb-Bi coolant technologies and to provide fundamental bases for future research efforts. Major parameters affecting the corrosion of structural materials in liquid metals are temperature, flow velocity, contents of impurities in coolant, compositions of structural materials, and so forth. It was already known that for traditional commercial austenitic steels of 18Cr-10Ni-Ti type and 12%Cr ferritic steels, the operating temperatures of Pb-Bi coolant cannot be raised above 400 dg C and 450 dg C, respectively. However, extensive researches have been performed to protect structural materials under higher operating temperature such as the development of various kinds of coating methods for steels and the investigations of coolant inhibition by different chemical elements. The available experimental results show that the effective methods to improve the performance of structural materials in Pb-Bi coolant are the development of suitable steel alloys, the creation of oxide type coatings, and the control of oxygen inhibition. According to the recently presented research results of URRS, utilization of these methods makes it possible to raise the operating temperature limit to 620-650 dg C. It provides the possibility of usage of Pb-Bi coolant for the transmutation system, HYPER some day. (Author). 27 refs., 6 tabs., 15 figs.

  20. Synthesis of the phase with T sub c =110 K in Bi(Pb)-Sr-Ca-Cu-O superconducting ceramics. Sintez fazy T sub c =110 K sverkhprovodyashchej keramiki sostava Bi(Pb)-Sr-Ca-Cu-O

    Energy Technology Data Exchange (ETDEWEB)

    Dubovitskij, A V; Makarov, E F; Makova, M K; Merzhanov, V A; Topnikov, V N [AN SSSR, Moscow (USSR). Inst. Khimicheskoj Fiziki

    1991-05-01

    Synthesis of 110 K single-phase bismuth ceramics (BiPb){sub 2}Sr{sub 2}Ca{sub n-1}Cu{sub n}O{sub x} was conducted in narrow temperature and time range. Diffusion of bismuth ions is proposed to be the decisive factor of synthesis of bismuth ceramics. The diffusion depends on prehistory of basic burden preparation and on its dispersivity and homogeneity in particluar. Optimal time of synthesis for lead doped ceramics of 2223 composition, synthesized from initial nitrate components, is equal to 65 h at 850 deg C. The role of Pb{sup 2+} ions is probably reduced to decrease of diffusion mobility of Bi{sup 3+} ions over the bismuth sublattice. Ceramics doping with CdO and CdCl{sub 2} compounds instead of lead stabilizes superconductivity in bismuth ceramics, but with worth superconducting parameters.

  1. Synthesis and evaluation of tetraphosphonates labelled with {sup 212}Bi, {sup 212}Pb and {sup 165}Er

    Energy Technology Data Exchange (ETDEWEB)

    Hassfjell, S.P

    1997-08-01

    The main goal of this work has been to achieve a synthesis of radiolabelled phosphonates for the improvement of diagnostic and therapy of osteoblastic osteosarcoma and sclerotic bone metastases. {sup 212}Bi-DOTMP is shown to be an in vivo stable bone seeking radiopharmaceutical with a potential for a {alpha}-particle therapy of the above mentioned diseases. It has biodistribution characteristics similar to {sup 153}Sm-EDTMP, which is now formally approved in several countries, most recently in the US. {sup 212}Pb-DOTMP is also a promising candidate having the advantage of increasing the effective half life of the {alpha}-emitter, although loss of some of the in vivo generated {sup 212}Bi may be a problem. A generator has been developed for the production of the {alpha}-emitting radionuclide {sup 212}Bi and its parent nuclide {sup 212}Pb. The generator is based on the emanation of {sup 220}Rn from ({sup 228}Th)barium stearate. The decay product of {sup 220}Rn, {sup 212}Pb deposits on the walls of a polyethylene bottle, and can be wasted off with distilled water. The generator shows no leakage of any long-lived parent nuclides, is easy to operate and has a high degree of radiation safety.

  2. The formation mechanism of eutectic microstructures in NiAl-Cr composites.

    Science.gov (United States)

    Tang, Bin; Cogswell, Daniel A; Xu, Guanglong; Milenkovic, Srdjan; Cui, Yuwen

    2016-07-20

    NiAl-based eutectic alloys, consisting of an ordered bcc matrix (B2) and disordered bcc fibers (A2), have been a subject of intensive efforts aimed at tailoring the properties of many of the currently used nickel-based superalloys. A thermodynamic phase field model was developed on a thermodynamic foundation and fully integrated with a thermo-kinetic database of the Ni-Al-Cr ternary system to elucidate the resulting peculiar eutectic microstructure. Invoking a variation of the liquid/solid interfacial thickness with temperature, we simulated the characteristic sunflower-like eutectic microstructures in the NiAl-Cr composites, consistent with experimental observations. The mechanism that governs the formation of the peculiar eutectic morphology was envisioned from the modeled evolutions associated with six sequential steps. Our calculations show that the conditional spinodal decomposition occurring in sequence could further trim and revise the microstructure of the eutectics by generating fine-domain structures, thereby providing an additional method to explore the novel NiAl-based eutectic composites with tunable properties at elevated temperatures.

  3. Construction and initial operation of MHD PbLi facility at UCLA

    Energy Technology Data Exchange (ETDEWEB)

    Smolentsev, S., E-mail: sergey@fusion.ucla.edu; Li, F.-C.; Morley, N.; Ueki, Y.; Abdou, M.; Sketchley, T.

    2013-06-15

    Highlights: • New MHD PbLi loop has been constructed and tested at UCLA. • Pressure diagnostics system has been developed and successfully tested. • Ultrasound Doppler velocimeter is tested as velocity diagnostics. • Experiments on pressure drop reduction have been performed. • Experiments on MHD flow in a duct with SiC flow channel insert are underway. -- Abstract: A magnetohydrodynamic flow facility MaPLE (Magnetohydrodynamic PbLi Experiment) that utilizes molten eutectic alloy lead–lithium (PbLi) as working fluid has been constructed and tested at University of California, Los Angeles. The loop operation parameters are: maximum magnetic field 1.8 T, PbLi temperature up to 350 °C, maximum PbLi flow rate with/without a magnetic field 15/50 l/min, maximum pressure head 0.15 MPa. The paper describes the loop itself and its major components, basic operation procedures, experience of handling PbLi, initial loop testing, flow diagnostics and current and near-future experiments. The obtained test results of the loop and its components have demonstrated that the new facility is fully functioning and ready for experimental studies of magnetohydrodynamic, heat and mass transfer phenomena in PbLi flows and also can be used in mock up testing in conditions relevant to fusion applications.

  4. Evaluation of Two 300 MWe Fourth Generation Pb-Bi Reactor System Concepts

    International Nuclear Information System (INIS)

    Miller, Laurence F.; Khuram Khan, M.; Williams, Wesley; Mynatt, F.R.

    2002-01-01

    This paper describes the evaluation of two 300 MWe modular Pb-Bi cooled reactor system concepts that can be field assembled from components shipped on standard rail cars or on trucks. Thus, the largest components must be smaller than 12' x 12' x 80' (3.66 m x 3.66 m x 24.4 m) and should weigh no more than 80 tons. One of these systems utilizes a cylindrical two-loop containment vessel for the core and the other is a slab design. The fuel for both designs consists of standard-sized metallic IFR fuel in 17 x 17 square array assemblies with a pitch-to-diameter ratio of 1.15. The coolant outlet temperature is limited by current material technology, which is estimated to be 550 C. The primary coolant inlet temperature is selected to be 350 C. This is well above the melting temperature of Pb-Bi, and it is expected to be sufficiently high to limit transient-induced thermal stresses to acceptable values. Coolant flow rates through the core and external piping are below 1 m/s. The results from neutronics calculations include power distributions, reactivity coefficients, and fuel depletion, and results from heat transfer calculations include temperatures and flow rates at various locations in the primary and secondary systems. The neutronic design calculations are accomplished by using a discrete ordinate transport code and a cross section processing system developed at Oak Ridge National Laboratory. Two-dimensional flux distributions are obtained with the DOORS system, and ORIGEN-S, coupled with KENO, is used for time-dependent depletion calculations. The thermal-hydraulic design of the core consists of heat transfer and fluid flow calculation for an average channel. The inlet and outlet temperatures, along with the fuel centerline temperature, are determined in conjunction with core flow rates, pumping power, and total power output. This is accomplished by using a lumped parameter steady-state model with a spreadsheet and by using a one-dimensional time-dependent model

  5. Decay of mass-separated 3.0min 195gBi to levels in 195Pb and shape coexistence in the neutron-deficient odd-mass Pb isotopes

    International Nuclear Information System (INIS)

    Griffin, J.C.; Braga, R.A.; Fink, R.W.; Bingham, C.R.; Coenen, E.; Huyse, M.; Duppen, P. van

    1991-01-01

    The radioactive decay of mass-separated 3.0 m 195g Bi to 195 Pb has been studied with the UNISOR and LISOL facilities. Time-sequenced spectra of γ-rays, X-rays, and conversion electrons have been obtained, together with γγt, γXt, eγt, and eXt coincidence data. From this information, a decay scheme has been constructed consisting of 23 excited states and 34 transitions in 195 Pb. Transitions with E0 multipole admixtures, indicative of shape coexistence, have been found to de-excite positive-parity levels at 1093, 1329, and 1380 keV. The beta-decay energy of the 195 Bi ground state is deduced to be Q EC =4800 +600 -550 keV based on the measurement of γ-ray-gated K/β + ratios. The excitation energy of the i 13/2 isomer in 195 Pb has been determined to be 203±4 keV from the α-decays of 199m,g Po. (orig.)

  6. Magnetoresistance and magnetothermopower properties of Bi/Ca/Co/O and Bi(Pb)/Ca/Co/O misfit layer cobaltites

    CERN Document Server

    Maignan, A; Hervieu, M; Michel, C; Pelloquin, D; Khomskii, D

    2003-01-01

    Two new compounds of the Bi/Ca/Co/O and Bi(Pb)/Ca/Co/O systems have been prepared. Their structure is built up from the intergrowth of four rock-salt-type layers and one [CoO sub 2 ] hexagonal layer. Both cobaltites exhibit large thermopower values (S sub 3 sub 0 sub 0 sub K approx 140 mu V K sup - sup 1), low resistivity values (rho sub 3 sub 0 sub 0 sub K = 40-60 m OMEGA cm) and small thermal conductivities (kappa sub 3 sub 0 sub 0 sub K approx 1 W K sup - sup 1 m sup - sup 1). Furthermore, these compounds exhibit a negative magnetoresistance, (MR = rho sub H - rho sub H sub sub 0 /rho sub H sub = sub 0), reaching, at 2.5 K, - 85% in 7 T for the Bi/Ca/Co/O misfit cobaltite. A large negative magnetothermopower is also found for these cobaltites in the same temperature range. A qualitative explanation of the observed behaviour is proposed.

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

    DEFF Research Database (Denmark)

    Palcut, Marián; Sopoušek, J.; Trnková, L.

    2009-01-01

    ) 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...... were experimentally studied by the DSC technique. The microstructure of the samples was determined by the light microscopy and the composition of solidified phases was obtained by the energy-dispersive X-ray spectroscopy, respectively. The solidification behaviour under equilibrium conditions...

  8. Phase equilibria and interaction between the CsCl-PbCl{sub 2}-PbO system components

    Energy Technology Data Exchange (ETDEWEB)

    Arkhipov, Pavel A.; Zakiryanova, Irina D. [Russian Academy of Sciences, Ekatherinburg (Russian Federation). Inst. of High Temperature Electrochemistry; Kholkina, Anna S.; Bausheva, Alexandra V.; Khudorozhkova, Anastasia O. [Russian Academy of Sciences, Ekatherinburg (Russian Federation). Inst. of High Temperature Electrochemistry; Ural Federal Univ., Ekatherinburg (Russian Federation)

    2015-07-01

    Thermal analysis was applied to determine liquidus temperatures in the CsCl-PbCl{sub 2}-PbO system, with the PbO concentration ranging from 0 to 20 mol%. The temperature dependence of the PbO solubility in the CsCl-PbCl{sub 2} eutectic melt was studied, and the thermodynamic parameters of the PbO dissolution were calculated. The type, morphology, and composition of oxychloride ionic groupings in the melt were determined in situ using Raman spectroscopy.

  9. The sorption of 210Pb, 210Bi and 210Po on montmorillonite: a study with emphasis on reversibility aspects and on the effect of the radioactive decay of adsorbed nuclides

    International Nuclear Information System (INIS)

    Ulrich, H.J.; Degueldre, C.

    1993-01-01

    The influence of the ionic strength and of pH on the adsorption/desorption processes of Pb, Bi and Po on montmorillonite has been investigated. For Pb, a strong dependence of the adsorption and desorption processes on the ionic strength was observed at pH d ) are measured. They range from 10 3 to 10 5 ml . g -1 for Pb and from 10 4 to 10 7 ml . g -1 for 210 Bi and 210 Po. When adsorption and desorption coefficients are compared, an agreement is found for both adsorption/desorption R d 's of Pb, whereas, for Bi and Po adsorption R d 's were several orders of magnitude lower than those obtained for desorption. The chemical activities of free Bi and Po in the liquid phase are limited by the formation of Bi and Po-colloids prior to the sorption step. This fact could explain the differences in the R d values. While the adsorption of Pb was reversible, only very small amounts of BI and Po could be desorbed from the montmorillonite (quasi-irreversible adsorption). The radioactive decay of adsorbed 210 Pb to 210 Bi, which in turn decays to 210 Po, can lead to significant changes in the desorption behaviour of the daughter nuclides. Whereas the sorption is nearly irreversible if Bi and Po adsorb on montmorillonite from the aqueous phase, they desorb more easily if they are generated by the radioactive decay of adsorbed 210 Pb. The difference in the distribution coefficients R d is approximately one order of magnitude in the case of Po, and more than 2 orders of magnitude in the case of Bi. (orig.)

  10. Phase Evolution in and Creep Properties of Nb-Rich Nb-Si-Cr Eutectics

    Science.gov (United States)

    Gang, Florian; Kauffmann, Alexander; Heilmaier, Martin

    2018-03-01

    In this work, the Nb-rich ternary eutectic in the Nb-Si-Cr system has been experimentally determined to be Nb-10.9Si-28.4Cr (in at. pct). The eutectic is composed of three main phases: Nb solid solution (Nbss), β-Cr2Nb, and Nb9(Si,Cr)5. The ternary eutectic microstructure remains stable for several hundred hours at a temperature up to 1473 K (1200 °C). At 1573 K (1300 °C) and above, the silicide phase Nb9(Si,Cr)5 decomposes into α-Nb5Si3, Nbss, and β-Cr2Nb. Under creep conditions at 1473 K (1200 °C), the alloy deforms by dislocation creep while the major creep resistance is provided by the silicide matrix. If the silicide phase is fragmented and, thus, its matrix character is destroyed by prior heat treatment [ e.g., at 1773 K (1500 °C) for 100 hours], creep is mainly controlled by the Laves phase β-Cr2Nb, resulting in increased minimum strain rates. Compared to state of the art Ni-based superalloys, the creep resistance of this three-phase eutectic alloy is significantly higher.

  11. Experimental Liquidus Studies of the Pb-Cu-Si-O System in Equilibrium with Metallic Pb-Cu Alloys

    Science.gov (United States)

    Shevchenko, M.; Nicol, S.; Hayes, P. C.; Jak, E.

    2018-03-01

    Phase equilibria of the Pb-Cu-Si-O system have been investigated in the temperature range from 1073 K to 1673 K (800 °C to 1400 °C) for oxide liquid (slag) in equilibrium with solid Cu metal and/or liquid Pb-Cu alloy, and solid oxide phases: (a) quartz or tridymite (SiO2) and (b) cuprite (Cu2O). High-temperature equilibration on silica or copper substrates was performed, followed by quenching, and direct measurement of Pb, Cu, and Si concentrations in the liquid and solid phases using the electron probe X-ray microanalysis has been employed to accurately characterize the system in equilibrium with Cu or Pb-Cu metal. All results are projected onto the PbO-"CuO0.5"-SiO2 plane for presentation purposes. The present study is the first-ever systematic investigation of this system to describe the slag liquidus temperatures in the silica and cuprite primary phase fields.

  12. Bandgap engineering of lead-free double perovskite Cs{sub 2}AgBiBr{sub 6} through trivalent metal alloying

    Energy Technology Data Exchange (ETDEWEB)

    Du, Ke-zhao; Mitzi, David B. [Department of Mechanical Engineering and Materials Science, and Department of Chemistry, Duke University, Durham, NC (United States); Meng, Weiwei; Wang, Xiaoming; Yan, Yanfa [Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, OH (United States)

    2017-07-03

    The double perovskite family, A{sub 2}M{sup I}M{sup III}X{sub 6}, is a promising route to overcome the lead toxicity issue confronting the current photovoltaic (PV) standout, CH{sub 3}NH{sub 3}PbI{sub 3}. Given the generally large indirect band gap within most known double perovskites, band-gap engineering provides an important approach for targeting outstanding PV performance within this family. Using Cs{sub 2}AgBiBr{sub 6} as host, band-gap engineering through alloying of In{sup III}/Sb{sup III} has been demonstrated in the current work. Cs{sub 2}Ag(Bi{sub 1-x}M{sub x})Br{sub 6} (M=In, Sb) accommodates up to 75 % In{sup III} with increased band gap, and up to 37.5 % Sb{sup III} with reduced band gap; that is, enabling ca. 0.41 eV band gap modulation through introduction of the two metals, with smallest value of 1.86 eV for Cs{sub 2}Ag(Bi{sub 0.625}Sb{sub 0.375})Br{sub 6}. Band structure calculations indicate that opposite band gap shift directions associated with Sb/In substitution arise from different atomic configurations for these atoms. Associated photoluminescence and environmental stability of the three-metal systems are also assessed. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Electronic structure of bismuth in high-temperature superconductor Bi1.6Pb0.4Sr2Ca2.5Cu3.5Oσ

    International Nuclear Information System (INIS)

    Band, I.M.; Egorovm, A.I.; Karazhanova, G.I.

    1990-01-01

    The shifts of K α1 X-ray of bismuth in the HTS-ceramic Bi 1.6 Pb 0.4 Sr 2 Ca 2.5 Cu 5 O σ and Bi 2 O 3 are measured experimentally. It is shown that bismuth is threevalent in the HTS-ceramic. From comparison of the experimental values of shifts with theoretical values calculated within the framework of different modifications of Hartree-Fock method the effective charge at the bismuth atoms in these compounds is determined: q(Bi 2 O 3 )=1.5+2.0, q(Bi 1.6 Pb 0.4 Sr 2 Ca 2.5 Cu 3.5 O σ )= 1.6+2.1. It was suggested, That the Bi significant covalence degree in HTS-ceramic may be a cause of noticeable contribution of the Bi 6p-states in the density of states at Fermi-level. 13 refs.; 1 fig.; 2 tabs

  14. Effect of Sintering Time on Superconducting Wire Bi-Pb-Sr-Ca-Cu-O With Dopant MgO Sheated Ag Using Powder in Tube Method

    Directory of Open Access Journals (Sweden)

    Hariyati Lubis

    2018-01-01

      DAFTAR PUSTAKA Abbas M.M., Abass L.K and Salman U., (2012, Influences of Sintering Time on the Tc of Bi2-xCuxPb0.3Sr2Ca2Cu3010+ High Temperature Superconductors, Energy Procedia 18, 215-224  Abbas, M.M., Abbas, L.K., Bahedh, H.S. 2015. Superconducting Properties of Bi2-SbxPb0,3Sr1,9Ba0,1Ca2Cu3O10+δ Compounds. Journal of Applied Science Research. 11. 22: 164-172 Darsono, N., Imaduddin, A., Raju, K., Yoon, D.H., (2015, Synthesis and Characterization of Bi1.6Pb0.4Sr2Ca2Cu3O7 Superconducting Oxide by High-Energy Milling, J Supercond Nov Magn. E. Chew,. (2010, Superconducting Transformer Design And Construction, University of Canterbury, Christchurch, New Zealand. March Hamadneh, I., Halim, S. A., dan Lee, C. K., (2006,  Characterization of Bi1.6Pb0.4Sr2Ca2Cu3Oy Ceramic Superconductor Prepared Via Coprecipitation Method at Different Sintering Time, J. Mater. Sci, 41: 5526-5530. Hermiz G.Y., Aljurani B.A., Beayaty M.A., (2014, Effect of Mn Substitution on the Superconducting Properties of Bi1.7Pb0,3Sr2Ca2-xMnxCu3O10+, International Journal Of Engineering and Advanced Technology (IJEAT. 3. 4: 213-217 John R Hull, (2003, Applications of high-temperature superconductors in power technology, Reports on Progress in Physics, Volume 66, Number 11 Lu, X.Y., Yi, D., Chen, H., Nagata, A. 2016. Effect of Sn, MgO and Ag2O mix-doping on the formation and superconducting properties of Bi-2223 Ag/tapes. Physics Procedia. 81: 129-132 Meretliev Sh., Sadykov K.B., Berkeliev A., (2000, Doping of High Temperature Superconductors, Turk J Phy.24: 39-48 Mohammed, N. H., Ramadhan A., Ali I. A., Ibrahim, I. H., dan Hassan, M. S, (2012, Optimizing the Preparation Conditions of Bi-2223 Superconducting Phase Using PbO and PbO2, Materials Sciences and Applications, 3: 224-233. Roumie, M., Marhaba, S., Awad R., Kork M., Hassan I., Mawassi R., (2014, Effect of Fe2O3 Nano-Oxide Addition on the Superconducting Properties of the (Bi,Pb-2223 Phase, Journal of Supercond Nov Magn, 27: 143-153 Serkan

  15. Positron lifetime studies of 100-MeV oxygen irradiated Pb-doped Bi-2223 superconductors

    NARCIS (Netherlands)

    Banerjee, T.; Viswanath, R.N.; Kanjilal, D.; Kumar, R.; Ramasamy, S.

    2000-01-01

    Positron lifetime studies have been carried out for unirradiated and 100-MeV oxygen ion irradiated Pb-doped Bi-2223 superconductors. The analysis of positron lifetime spectra revealed three lifetime components: a short lifetime, τ1 = 153–196 ps; an intermediate lifetime, τ2 = 269–339 ps; and a long

  16. Densities of Pb-Sn alloys during solidification

    Science.gov (United States)

    Poirier, D. R.

    1988-01-01

    Data for the densities and expansion coefficients of solid and liquid alloys of the Pb-Sn system are consolidated in this paper. More importantly, the data are analyzed with the purpose of expressing either the density of the solid or of the liquid as a function of its composition and temperature. In particular, the densities of the solid and of the liquid during dendritic solidification are derived. Finally, the solutal and thermal coefficients of volume expansion for the liquid are given as functions of temperature and composition.

  17. Microscopic fracture of filaments and its relation to the critical current under bending deformation in (Bi,Pb)2Sr2Ca2Cu3O10 composite superconducting tapes

    International Nuclear Information System (INIS)

    Hojo, Masaki; Nakamura, Mitsuhiro; Matsuoka, Tomoe; Tanaka, Mototsugu; Ochiai, Shojiro; Sugano, Michinaka; Osamura, Kozo

    2003-01-01

    The strain dependence of the critical current, I c , of (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10 (Bi2223)/Ag/Ag-Mg composite superconducting tapes has been studied both experimentally and analytically under bending deformation. Tests have been carried out for one type of tape used in the VAMAS bending round-robin programme. The complex stress-strain behaviour of each component was first analysed in tension. This was done by comparing the stress-strain curves of composite tapes with those of Ag and Ag-Mg alloy tapes. Here, the plastic deformation (work hardening) of Ag and Ag-Mg alloy, and the thermal residual strain due to the manufacturing process were taken into account. The fracture strain of Bi2223 filaments was inversely determined as 0.08% to meet the global tensile stress-strain curve of the composite tape. The calculated stress-strain curves finally agreed well with the experimental results when the as-supplied bending strain was taken into account. Then, the analysis was modified to fit the bending deformation. Here, the movement of the neutral axis due to the non-symmetric and elastic-plastic stress-strain curves of the components and their Bauschinger effect were taken into account. The relative decrease of I c with the increase in the Bi2223 tape curvature was calculated from the volume fraction of the broken filaments. The calculated I c agreed well with the experimental results when the movement of the neutral axis and the Bauschinger effect were taken into account. Microscopic observation of the spatial distribution of the filament fracture indicated that the damage occurred at the outermost layer on the tensile side when the curvature was small, and then the damage front shifted to the inside layers. The observed fracture behaviour of the Bi2223 filament agreed well with the estimated location based on the above analysis

  18. Behavior of the Pb–Li alloy impurities by ICP-MS

    International Nuclear Information System (INIS)

    Conde, E.; Barrado, A.I.; Pascual, L.; Fernández, M.; Salazar, J.M. Gómez de; Barrena, M.I.; Quiñones, J.

    2014-01-01

    Highlights: • In the new test blanket modules (TBM), Pb–Li alloy plays a key role in the new commercial fusion reactors functionality. • It is important to have a complete characterization to define their physicochemical properties and their regenerative function inside the blanket. • Methodology developed is a key tool that allows performing quality control procedures. • It is essential to determine concentrations of major and trace elements presents in Pb–Li alloy. It allows performing quality control procedures. • The inductively coupled plasma mass spectrometry (ICP-MS) is a highly sensitive technique, so enables very low detection limits. - Abstract: The ITER and DEMO projects are developing new test blanket modules (TBM), such as HCLL where the Li–Pb alloy plays a key role in the new commercial fusion reactors functionality. Lithium–lead eutectic alloy has no known uses outside of fusion technology, so the available databases of this material are currently incomplete. It is very important, within the material specifications, to have a complete characterization in order to define their chemical and physical properties, because any variation in the alloy composition has significant consequences in their behavior, and therefore in their regenerative function inside the blanket. This report provides a procedure to perform a wide material characterization, assessing the concentrations of major elements, as well as a review of trace level impurities that can be found both in the eutectic alloy as in starting materials. In this determination inductively coupled plasma mass spectrometry (ICP-MS) technique plays an important role, because as a highly sensitive technique it allows very low detection limits

  19. Determination of the diffusion coefficients of iron and chromium in Pb17Li at 500 deg C

    International Nuclear Information System (INIS)

    Simon, N.; Flament, T.; Terlain, A.

    1992-01-01

    The diffusion of the dissolved metallic species in a liquid metal towards the boundary layer is one of the elementary steps of the overall mass transfer process induced by thermal gradient. This phenomenon is very probably the limiting step in the mass transfer of martensitic Fe-Cr steels in the presence of Pb17Li liquid eutectic alloy. For estimating diffusion flux, the diffusion coefficients of iron and chromium in Pb17Li are needed but are not known. Consequently these data have been determined in CEA laboratory by measuring metal loss of cylindrical specimens after rotation at 500 deg C in Pb17Li for several hours and applying the first Fick diffusion law in the boundary layer whose the thickness has been previously determined by EISENBERG. After a description of the experimental device, the results are presented and discussed

  20. A Eutectic Melting Study of Double Wall Cladding Tubes of FeCrAl and Zircaloy-4

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Woojin; Son, Seongmin; Lee, You Ho; Lee, Jeong Ik; Ryu, Ho Jin [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Jeong, Eun [Kyunghee University, Yongin (Korea, Republic of)

    2015-10-15

    The eutectic melting behavior of FeCrAl/Zircaloy-4 double wall cladding tubes was investigated by annealing at various temperatures ranging from 900 .deg. C to 1300 .deg. C. It was found that significant eutectic melting occurred after annealing at temperatures equal to or higher than 1150 .deg. C. It means that an additional diffusion barrier layer is necessary to limit the eutectic melting between FeCrAl and Zircaloy-4 alloy cladding tubes. Coating of FeCrAl layers on the Zr alloy cladding tube is being investigated for the development of accident tolerant fuel by exploiting of both the oxidation resistance of FeCrAl alloys and the neutronic advantages of Zr alloys. Coating of FeCrAl alloys on Zr alloy cladding tubes can be performed by various techniques including thermal spray, laser cladding, and co-extrusion. Son et al. also reported the fabrication of FeCrAl/Zr ally double wall cladding by the shrink fit method. For the double layered cladding tubes, the thermal expansion mismatch between the dissimilar materials, severe deformation or mechanical failure due to the evolution of thermal stresses can occur when there is a thermal cycling. In addition to the thermal stress problems, chemical compatibilities between the two different alloys should be investigated in order to check the stability and thermal margin of the double wall cladding at a high temperature. Generally, it is considered that Zr alloy cladding will maintain its mechanical integrity up to 1204 .deg. C (2200 .deg. F) to satisfy the acceptance criteria for emergency core cooling systems.

  1. Structural studies of five layer Aurivillius oxides: A2Bi4Ti5O18 (A=Ca, Sr, Ba and Pb)

    International Nuclear Information System (INIS)

    Ismunandar; Kamiyama, T.; Hoshikawa, A.; Zhou, Q.; Kennedy, B.J.; Kubota, Y.; Kato, K.

    2004-01-01

    The room temperature structures of the five layer Aurivillius phases A 2 Bi 4 Ti 5 O 18 , (A=Ca, Sr, Ba and Pb) have been refined from powder neutron diffraction data using the Rietveld method. The structures consist of [Bi 2 O 2 ] 2+ layers interleaved with perovskite-like [A 2 Bi 2 Ti 5 O 16 ] 2- blocks. The structures were refined in the orthorhombic space group B2eb (SG. No. 41), Z=4, and the unit cell parameters of the oxides are a=5.4251(2), b=5.4034(1), c=48.486(1); a=5.4650(2), b=5.4625(3), c=48.852(1); a=5.4988(3), b=5.4980(4), c=50.352(1); a=5.4701(2), b=5.4577(2), c=49.643(1) for A=Ca, Sr, Ba and Pb, respectively. The structural features of the compounds were found similar to n=2-4 layers bismuth oxides. The strain caused by mismatch of cell parameter requirements for the [Bi 2 O 2 ] 2+ layers and perovskite-like [A 2 Bi 2 Ti 5 O 16 ] 2- blocks were relieved by tilting of the TiO 6 octahedra. Variable temperature synchrotron X-ray studies for Ca and Pb compounds showed that the orthorhombic structure persisted up to 675 and 475K, respectively. Raman spectra of the compounds are also presented

  2. The electronic and optical properties of quaternary GaAs1-x-y N x Bi y alloy lattice-matched to GaAs: a first-principles study.

    Science.gov (United States)

    Ma, Xiaoyang; Li, Dechun; Zhao, Shengzhi; Li, Guiqiu; Yang, Kejian

    2014-01-01

    First-principles calculations based on density functional theory have been performed for the quaternary GaAs1-x-y N x Bi y alloy lattice-matched to GaAs. Using the state-of-the-art computational method with the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional, electronic, and optical properties were obtained, including band structures, density of states (DOSs), dielectric function, absorption coefficient, refractive index, energy loss function, and reflectivity. It is found that the lattice constant of GaAs1-x-y N x Bi y alloy with y/x =1.718 can match to GaAs. With the incorporation of N and Bi into GaAs, the band gap of GaAs1-x-y N x Bi y becomes small and remains direct. The calculated optical properties indicate that GaAs1-x-y N x Bi y has higher optical efficiency as it has less energy loss than GaAs. In addition, it is also found that the electronic and optical properties of GaAs1-x-y N x Bi y alloy can be further controlled by tuning the N and Bi compositions in this alloy. These results suggest promising applications of GaAs1-x-y N x Bi y quaternary alloys in optoelectronic devices.

  3. Vacuum distillation for the separation of LiCl-KCl eutectic salt and cadmium in pyro process

    International Nuclear Information System (INIS)

    Kwon, S. W.; Park, K. M.; Lee, S. J.; Park, S. B.; Woo, M. S.; Kim, K. R.; Kim, J. G.; Ahn, D. H.; Lee, H. S.

    2010-10-01

    Electrorefining is a key step in pyro processing. Electrorefining process is generally composed of two recovery steps- a deposit of uranium onto a solid cathode (electrorefining) and then the recovery of the remaining uranium and Tru (Transuranic) elements simultaneously by a liquid cadmium cathode (electrowinning). In this study, distillation experiments of a LiCl-KCl eutectic salt and cadmium metal were carried out to examine the distillation behaviors for the development of the electrorefining and the electrowinning processes. The experimental set-up was composed of a distillation tower with an evaporator and a condenser, vacuum pump, control unit, and an off gas treatment system. The solid-liquid separation prior to distillation of the LiCl-KCl eutectic salt was proposed and found to be feasible for the reduction of the burden of the distillation process. The LiCl-KCl eutectic salt was successfully distilled after the liquid salt separation. Distillation experiments for cadmium metal were also carried out. The apparent evaporation rates of LiCl-KCl eutectic salt and cadmium increased with an increasing temperature. The evaporation behaviors of cadmium metal and cadmium-cerium alloy were compared. Cadmium in the alloy was successfully distilled and separated from cerium. The evaporation rate of cadmium in the alloy was lower than that of cadmium metal. The low evaporation rate of the alloy was probably caused by the formation of an intermetallic compound and the residual salt during the preparation of the alloy. Therefore, the distillation temperature for the distillation of the liquid cathode should be higher than the distillation of cadmium metal. The measured evaporation rates of the eutectic salt and cadmium were compared with the values calculated by a relation based on the kinetics of gases. The theoretical values of the evaporation rate calculated by the Hertz-Langmuir relation were higher than the experimental values. The deviations were compensated for

  4. Cross-sections of (p, xn) nuclear reactions on Pb and Bi by 100 MeV protons

    Energy Technology Data Exchange (ETDEWEB)

    Oranj, Leila Mokhtari; Jung, Nam Suk; Oh, Joo Hee; Lee, Arim; Kim, Dong Hyun; Bae, Oryun; Lee, Hee Seock [POSTECH, Pohang (Korea, Republic of)

    2016-04-15

    The development of high-intensity and high-energy accelerator is gaining interest in Korea, in recent years. Rare Isotope Science Project (RISP), Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL), Korea Heavy Ion Medical Accelerator (KHIMA) facilities are being designed. In the frame of above projects, for the safety issue and shielding analysis of the accelerator facility, extensive studies including experimental and simulation on the production yields of residual nuclei induced in the accelerator materials such as Pb, Cu and Bi by protons and heavy ions are in progress. In this work, we measured cross-sections of {sup na}'tPb(p,xn){sup 206,205,204,20{sup ,202}}Bi and {sup 209}Bi(p, xn){sup 207,206,205,204},{sup 203}Po nuclear reactions by the 100-MeV protons. The present experimental data are in good agreement with the results of Titarenkoet al. and Gloris et al.. Experimental data were higher than theoretical data. In other words, results of TALYS code and data in TENDL library underestimated the measured crosss sections and library of TALYS code and TENDL need to be improved.

  5. THE NIOBIUM-THORIUM EUTECTIC ALLOY AS A HIGH-FIELD, HIGH-CURRENT SUPERCONDUCTOR

    Energy Technology Data Exchange (ETDEWEB)

    Cline, H. E.; Rose, R. M.; Wulff, J.

    1963-03-15

    Niobium-thorium eutectic alloys having fine acicuiar microstructures were produced by fast cooling frorn a vacuum melt. Although the solidified material was normal, continuity between the superconducting niobium-rich phase, which was essentially pure niobium, was attained by plastic deformation at room temperature. The resulting wire was tested for critical current at 4.2 deg K, in transverse magnetic fields up to 82.5 kilogauss; at the highest field, critical current densities of slightly more than 10/sup 4/ amps per square centimeter were observed. The critical current density was independent of applied field from 20 kilogauss to the highest field used; the level of critical current density depended on diameter in a manner that suggested dependence on cold work. It was concluded that the cold work reduced the thickness of the needles of niobium below the superconducting penetration depth, and brought them sufficiently close together to allow the superconducting correlation to interconnect the niobium, in the manner suggested by Cooper; furthermore, the constant critical current region may possibly extend to considerably higher fields. (auth)

  6. Al based ultra-fine eutectic with high room temperature plasticity and elevated temperature strength

    Energy Technology Data Exchange (ETDEWEB)

    Tiwary, C.S., E-mail: cst311@gmail.com [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, Karnataka (India); Kashyap, S. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, Karnataka (India); Kim, D.H. [Center for Non-Crystalline Materials, Department of Metallurgical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Chattopadhyay, K. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, Karnataka (India)

    2015-07-15

    Developments of aluminum alloys that can retain strength at and above 250 °C present a significant challenge. In this paper we report an ultrafine scale Al–Fe–Ni eutectic alloy with less than 3.5 at% transition metals that exhibits room temperature ultimate tensile strength of ~400 MPa with a tensile ductility of 6–8%. The yield stress under compression at 300 °C was found to be 150 MPa. We attribute it to the refinement of the microstructure that is achieved by suction casting in copper mold. The characterization using scanning and transmission electron microscopy (SEM and TEM) reveals an unique composite structure that contains the Al–Al{sub 3}Ni rod eutectic with spacing of ~90 nm enveloped by a lamellar eutectic of Al–Al{sub 9}FeNi (~140 nm). Observation of subsurface deformation under Vickers indentation using bonded interface technique reveals the presence of extensive shear banding during deformation that is responsible for the origin of ductility. The dislocation configuration in Al–Al{sub 3}Ni eutectic colony indicates accommodation of plasticity in α-Al with dislocation accumulation at the α-Al/Al{sub 3}Ni interface boundaries. In contrast the dislocation activities in the intermetallic lamellae are limited and contain set of planner dislocations across the plates. We present a detailed analysis of the fracture surface to rationalize the origin of the high strength and ductility in this class of potentially promising cast alloy.

  7. Elastic properties of zinc, cadmium, bismuth, thallium, tin, lead and their binary alloys with indium

    International Nuclear Information System (INIS)

    Magomedov, A.M.

    1986-01-01

    Rates of propagation of longitudinal and transverse acoustic waves in samples as well as density of Tl, Pb, Sn, Bi, Cd, Zn and their binary alloys with indium are determined. The results obtained are used for calculation of elasticity constants of these materials. It is stated that concentration dependences of elasticity constants for indium alloys have non-linear character; negative deflection from the additive line is observed

  8. Electrical properties and band structures of Pb1-x Snx Te alloys

    International Nuclear Information System (INIS)

    Ocio, Miguel

    1972-01-01

    Both p type alloys Pb 0.72 Sn 0.28 Te and Pb 0.53 Sn 0.47 Te have been studied in the present work. The main obtained results are the following: the materials have a two-valence band structure, the first band following non-parabolic Cohen's dispersion law; at low temperatures, carriers are scattered by ionized impurities; the Coulomb potentials being screened almost completely, impurities act like neutral centers. At room temperature, scattering by acoustic modes can explain lattice mobility behavior; reversing of the thermo-power, for samples with carrier densities of about 10 20 cm -3 , is possibly due to inter-band scattering between both valence bands; a very simple picture of the band parameters variations as a function of alloy fraction is suggested. (author) [fr

  9. Formation of nanocrystalline and amorphous phase of Al-Pb-Si-Sn-Cu powder during mechanical alloying

    International Nuclear Information System (INIS)

    Ran Guang; Zhou Jingen; Xi Shengqi; Li Pengliang

    2006-01-01

    Al-15%Pb-4%Si-1%Sn-1.5%Cu alloys (mass fraction, %) were prepared by mechanical alloying (MA). Phase transformation and microstructure characteristics of the alloy powders were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the nanocrystalline supersaturated solid solutions and amorphous phase in the powders are obtained during MA. The effect of ball milling is more evident to lead than to aluminum. During MA, the mixture powders are firstly fined, alloyed, nanocrystallized and then the nanocrystalline partly transforms to amorphous phase. A thermodynamic model is developed based on semi-experimental theory of Miedema to calculate the driving force for phase evolution. The thermodynamic analysis shows that there is no chemical driving force to form a crystalline solid solution from the elemental components. But for the amorphous phase, the Gibbs free energy is higher than 0 for the alloy with lead content in the ranges of 0-86.8 at.% and 98.4-100 at.% and lower than 0 in range of 86.8-98.4 at.%. For the Al-2.25 at.%Pb (Al-15%Pb, mass fraction, %), the driving force for formation of amorphization and nanocrystalline supersaturated solid solutions are provided not by the negative heat of mixing but by mechanical work

  10. Effect of titanium on the near eutectic grey iron

    DEFF Research Database (Denmark)

    Moumeni, Elham; Tiedje, Niels Skat; Hattel, Jesper Henri

    The effect of Titanium on the microstructure of grey iron was investigated experimentally in this work. Tensile test bars of grey cast iron of near eutectic alloys containing 0.01, 0.1, 0.26 and 0.35% Ti, respectively were made in green sand moulds. Chemical analysis, metallographic investigation...

  11. Estimation of Bi induced changes in the direct E{sub 0} band gap of III–V-Bi alloys and comparison with experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Samajdar, D.P., E-mail: dipprakash010@gmail.com; Dhar, S.

    2016-03-01

    Quantum dielectric Theory (QDT) is used to explain the band gap bowing effect observed in III–V-Bismides such as InSb{sub 1−x}Bi{sub x}, InAs{sub 1−x}Bi{sub x}, InP{sub 1−x}Bi{sub x}, GaSb{sub 1−x}Bi{sub x}, GaAs{sub 1−x}Bi{sub x} and GaP{sub 1−x}Bi{sub x.} The dependence of the direct E{sub 0} band gap for these alloys on Bi mole fraction is calculated using QDT which requires the evaluation of the bowing parameter c. The bowing parameter gives the deviation of the direct E{sub 0} band gap from the linear relationship of E{sub 0} with Bi mole fraction. The band gap reduction values obtained using QDT are compared with those calculated using Virtual Crystal approximation (VCA) and Valence Band Anticrossing (VBAC) model as well as with the reported experimental data and the results of the comparison shows excellent agreement.

  12. Cu-Pb rheocast alloy as joining material for CFC composites

    International Nuclear Information System (INIS)

    Salvo, M.

    1995-01-01

    High heat flux components for future use in thermonuclear fusion reactors are designed as layered structures. The assembling of the different parts (armour, heat sink and external structure) requires a joint which could withstand large heat loads and thermal stresses. In this paper we examined a 50 wt% Pb-Cu rheocast alloy (RCA) as joining material for the armour/heat sink joint. The alloy was prepared in vacuum in a rotational furnace and was characterized by SEM-EDS analysis and heating microscopy. The obtained microstructure was globular as foreseen and it remained after prolonged heating at 650 C. The alloy showed very good ductility: sheets of about 200 μm were rolled starting from about 1x1x1 cm 3 cubes. The alloy was successful in joining both the armour and the heat sink materials, respectively, carbon fibre reinforced composites and copper. Initial mechanical testing shows that the technique is viable for the foreseen applications in the field of thermonuclear fusion reactors. (orig.)

  13. Combinatorial processing libraries for bulk BiFeO3-PbTiO3 piezoelectric ceramics

    International Nuclear Information System (INIS)

    Hu, W.; Tan, X.; Rajan, K.

    2010-01-01

    A high throughput approach for generating combinatorial libraries with varying processing conditions for bulk ceramics has been developed. This approach utilized the linear temperature gradient in a tube furnace to screen a whole temperature range for optimized preparation. With this approach, the processing of 0.98[0.6BiFeO 3 -0.4PbTiO 3 ]-0.02Pb(Mg 1/3 Nb 2/3 )O 3 ceramic powders and pellets for high-temperature piezoelectric applications was demonstrated to identify the best synthesis conditions for phase purity. The dielectric property measurement on the as-processed solid solution ceramics confirmed the high Curie temperature and the improved loss tangent with the Pb(Mg 1/3 Nb 2/3 )O 3 doping. (orig.)

  14. Influence of micro-additions of bismuth on structures, mechanical and electrical transport properties of rapidly solidified Sn-3.5% Ag Alloy from melt

    International Nuclear Information System (INIS)

    El Bahay, M.M.; Mady, H.A.

    2005-01-01

    The present study was undertaken to investigate the influence of the Bi addition in the Sn-3.5 Ag rapidly solidified binary system for use as a Pb-free solder. The resulting properties of the binary system were extended to the Sn based ternary systems Sn 9 6.5-X Ag 3 .5 Bi x (0≤ X ≤ 2.5) solder. The structure and electrical resistivity of rapidly solidified (melt spun) alloys have been investigated. With the addition of up to 2.5 mass % Bi, the melting temperature decreases from 221.1 to 214.8 degree C. Wetting contact angle of the six alloys on Cu Zn 3 0 substrate are carried out at 573 K. Microhardness evaluations were also performed on the Sn-Ag-Bi alloys. The measured values and other researcher's results were compared with the calculated data

  15. (Bi, Pb).sub.2, Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.x superconductor and method of making same utilizing sinter-forging

    Science.gov (United States)

    Chen, Nan; Goretta, Kenneth C.; Lanagan, Michael T.

    1998-01-01

    A (BiPb).sub.2 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.x (Bi223) superconductor with high J.sub.c, phase purity, density and mechanical strength is formed from Bi2223 powder which is synthesized from a mixture of Bi.sub.2 O.sub.3, PbO, SrCO.sub.3, CaCo.sub.3 and CuO. The mixture is milled, then dried and calcined to synthesize the Bi2223 powder with the desired phase purity. The calcination is performed by heating the dried mixture for 50 hours at 840.degree. C. The partially synthesized powder is then milled for 1-4 hours before calcining further for another 50 hours at 855.degree. C. to complete the synthesis. After calcination, the Bi2223 powder is cold pressed to a predetermined density and sinter forged under controlled temperature and time to form a Bi2223 superconductor with the desired superconducting properties.

  16. (Bi, Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} superconductor and method of making same utilizing sinter-forging

    Science.gov (United States)

    Chen, N.; Goretta, K.C.; Lanagan, M.T.

    1998-10-13

    A (BiPb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}(Bi223) superconductor with high J{sub c}, phase purity, density and mechanical strength is formed from Bi2223 powder which is synthesized from a mixture of Bi{sub 2}O{sub 3}, PbO, SrCO{sub 3}, CaCo{sub 3} and CuO. The mixture is milled, then dried and calcined to synthesize the Bi2223 powder with the desired phase purity. The calcination is performed by heating the dried mixture for 50 hours at 840 C. The partially synthesized powder is then milled for 1--4 hours before calcining further for another 50 hours at 855 C to complete the synthesis. After calcination, the Bi2223 powder is cold pressed to a predetermined density and sinter forged under controlled temperature and time to form a Bi2223 superconductor with the desired superconducting properties. 5 figs.

  17. Structural and electronic investigations of PbTa4O11 and BiTa7O19 constructed from α-U3O8 types of layers

    Science.gov (United States)

    Boltersdorf, Jonathan; Maggard, Paul A.

    2015-09-01

    The PbTa4O11 and BiTa7O19 phases were prepared by ion-exchange and solid-state methods, respectively, and their structures were characterized by neutron time-of-flight diffraction and Rietveld refinement methods (PbTa4O11, R 3 (No. 146), a=6.23700(2) Å, c=36.8613(1) Å; BiTa7O19, P 6 bar c 2 (No. 188), a=6.2197(2) Å, c=20.02981(9) Å). Their structures are comprised of layers of TaO6 octahedra surrounded by three 7-coordinate Pb(II) cations or two 8-coordinate Bi(III) cations. These layers alternate down the c-axis with α-U3O8 types of single and double TaO7 pentagonal bipyramid layers. In contrast to earlier studies, both phases are found to crystallize in noncentrosymmetric structures. Symmetry-lowering structural distortions within PbTa4O11, i.e. R 3 bar c →R3, are found to be a result of the displacement of the Ta atoms within the TaO7 and TaO6 polyhedra, towards the apical and facial oxygen atoms, respectively. In BiTa7O19, relatively lower reaction temperatures leads to an ordering of the Bi/Ta cations within a lower-symmetry structure, i.e., P63/mcm→ P 6 bar c 2 . In the absence of Bi/Ta site disorder, the Ta-O-Ta bond angles decrease and the Ta-O bond distances increase within the TaO7 double layers. Scanning electron microscopy images reveal two particle morphologies for PbTa4O11, hexagonal rods and finer irregularly-shaped particles, while BiTa7O19 forms as aggregates of irregularly-shaped particles. Electronic-structure calculations confirm the highest-energy valence band states are comprised of O 2p-orbitals and the respective Pb 6s-orbital and Bi 6s-orbital contributions. The lowest-energy conduction band states are composed of Ta 5d-orbital contributions that are delocalized over the TaO6 octahedra and layers of TaO7 pentagonal bipyramids. The symmetry-lowering distortions in the PbTa4O11 structure, and the resulting effects on its electronic structure, lead to its relatively higher photocatalytic activity compared to similar structures without

  18. CaO-matrix processing of MnBi alloys for permanent magnets

    Directory of Open Access Journals (Sweden)

    A. M. Gabay

    2017-05-01

    Full Text Available The possibility to suppress agglomeration of MnBi alloy particles during milling and their unwanted sintering during subsequent annealing was explored by embedding the particles in CaO through co-milling. A 15 h annealing of the micron-sized MnBi particles embedded in the CaO matrix at 300 °C is not accompanied by sintering or growth of the particles while it significantly increases their coercivity – presumably by healing the milling-induced crystal defects. After separation from the CaO matrix, the annealed MnBi powder combines a calculated energy product of 10 MGOe with a room-temperature coercivity of 14.4 kOe. At the same time, the partial loss and degradation of the MnBi low-temperature phase during warm compaction of the powders makes the effect of the CaO-matrix annealing less pronounced in the case of fully dense magnets; the residue from the solvents employed for the removal of the CaO might have contributed to the decline of the properties. Still, a relatively high room-temperature coercivity of 8.5 kOe was obtained for the fuslly-dense MnBi magnet exhibiting an energy product of 5.3 MGOe.

  19. Algorithm of calculation of multicomponent system eutectics using electronic digital computer

    International Nuclear Information System (INIS)

    Posypajko, V.I.; Stratilatov, B.V.; Pervikova, V.I.; Volkov, V.Ya.

    1975-01-01

    A computer algorithm is proposed for determining low-temperature equilibrium regions for existing phases. The algorithm has been used in calculating nonvariant parameters (temperatures of melting of eutectics and the concentrations of their components) for a series of trinary systems, among which are Ksub(long)Cl, WO 4 , SO 4 (x 1 =K 2 WO 4 ; x 2 =K 2 SO 4 ), Ag, Cd, Pbsub(long)Cl(x 1 =CdCl 2 , x 2 =PbCl 2 ); Ksub(long)F, Cl, I (x 1 =KF, x 2 =KI). The proposed method of calculating eutectics permits the planning of the subsequent experiment in determining the parameters of the eutectics of multicomponent systems and the forecasting of chemical interaction in such systems. The algorithm can be used in calculating systems containing any number of components

  20. Evaluation of Pb–17Li compatibility of ODS Fe-12Cr-5Al alloys

    Energy Technology Data Exchange (ETDEWEB)

    Unocic, Kinga A., E-mail: unocicka@ornl.gov; Hoelzer, David T.

    2016-10-15

    The Dual Coolant Lead Lithium (DCLL: eutectic Pb–17Li and He) blanket concept requires improved Pb–17Li compatibility with ferritic steels in order to demonstrate acceptable performance in fusion reactors. As an initial step, static Pb-17at.%Li (Pb-17Li) capsule experiments were conducted on new oxide dispersion strengthened (ODS) FeCrAl alloys ((1) Y{sub 2}O{sub 3} (125Y), (2) Y{sub 2}O{sub 3} + ZrO{sub 2} (125YZ), (3) Y{sub 2}O{sub 3} + HfO{sub 2} (125YH), and (4) Y{sub 2}O{sub 3} + TiO{sub 2} (125YT)) produced at ORNL via mechanical alloying (MA). Tests were conducted in static Pb–17Li for 1000 h at 700 °C. Alloys showed promising compatibility with Pb–17Li with small mass change after testing for 125YZ, 125YH and 125YT, while the 125Y alloy experienced the highest mass loss associated with some oxide spallation and subsequent alloy dissolution. X-ray diffraction methods identified the surface reaction product as LiAlO{sub 2} on all four alloys. A small decrease (∼1 at.%) in Al content beneath the oxide scale was observed in all four ODS alloys, which extended 60 μm beneath the oxide/metal interface. This indicates improvements in alloy dissolution by decreasing the amount of Al loss from the alloy. Scales formed on 125YZ, 125YH and 125YT were examined via scanning transmission electron microscopy (S/TEM) and revealed incorporation of Zr-, Hf-, and Ti-rich precipitates within the LiAlO{sub 2} product, respectively. This indicates an inward scale growth mechanism. Future work in flowing Pb–17Li is needed to further evaluate the effectiveness of this strategy in a test blanket module. - Highlights: • Investigation of Pb-17Li compatibility of new ODS Fe-12Cr5Al. • Promising small mass change after static Pb-17Li exposure. • LiAlO{sub 2} formed on the surface during Pb-17Li exposure. • Oxide precipitates incorporated within the LiAlO{sub 2} product. • An inward scale growth mechanism was identified.

  1. Investigating the local structure of B-site cations in (1-x)BaTiO3-xBiScO3 and (1-x)PbTiO3-xBiScO3 using X-ray absorption spectroscopy

    Science.gov (United States)

    Blanchard, Peter E. R.; Grosvenor, Andrew P.

    2018-05-01

    The structural properties of (1-x)BaTiO3-xBiScO3 and (1-x)PbTiO3-xBiScO3 were investigated using powder X-ray diffraction and X-ray absorption spectroscopy. Diffraction measurements confirmed that substituting small amounts of BiScO3 into BaTiO3 initially stabilizes a cubic phase at x = 0.2 before impurity phases begin to form at x = 0.5. BiScO3 substitution also resulted in noticeable changes in the local coordination environment of Ti4+. X-ray absorption near-edge spectroscopy (XANES) analysis showed that replacing Ti4+ with Sc3+ results in an increase in the off-centre displacement of Ti4+ cations. Surprisingly, BiScO3 substitution has no effect on the displacement of the Ti4+ cation in the (1-x)PbTiO3-xBiScO3 solid solution.

  2. On The Utilization of (1-X)Cu-X Pb) Alloys for Gamma-Rays Shielding

    International Nuclear Information System (INIS)

    Abd El-Latif, A.A.; Saeid, Kh.S.; Abd El-Latif, A.A.

    2011-01-01

    The present work deals with the study of the attenuation properties of gamma rays for [(1-X) Cu -X Pb] alloys where, x=10%, 20%, 30%, and 40% Pb waste by weight. Investigation has been performed by measuring the transmitted gamma ray spectra behind cylindrical samples of [(1-X) Cu - X Pb] alloys of different thicknesses. A collimated beam of gamma ray measured by using γ - ray spectrometer NaI(Tl) Scintillation detector with multichannel analyzer (MCA) cassy. Total mass attenuation coefficients (μ/ρ) of γ-ray have been evaluated and calculated using measured results and XCOM code respectively . Comparison between measured and calculated results shows a reasonable divergence at 0.511 MeV ,and 0.662 MeV γ-ray energies, in addition there is a convergence at 1.17 MeV, 1.274 MeV, and 1.3 MeV γ-ray energies

  3. Corrosion Behavior of Alloy 625 in PbSO4-Pb3O4-PbCl2-ZnO-10 Wt Pct CdO Molten Salt Medium

    Science.gov (United States)

    Mohammadi Zahrani, E.; Alfantazi, A. M.

    2012-08-01

    Corrosion behavior and degradation mechanisms of alloy 625 under a 47.288 PbSO4-12.776 Pb3O4-6.844PbCl2-23.108ZnO-10CdO (wt pct) molten salt mixture under air atmosphere were studied at 873 K, 973 K, and 1073 K (600 °C, 700 °C, and 800 °C). Electrochemical impedance spectroscopy (EIS), open circuit potential (OCP) measurements, and potentiodynamic polarization techniques were used to evaluate the degradation mechanisms and characterize the corrosion behavior of the alloy. Morphology, chemical composition, and phase structure of the corrosion products and surface layers of the corroded specimens were studied by scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) and X-ray map analyses. Results confirmed that during the exposure of alloy 625 to the molten salt, chromium was mainly dissolved through an active oxidation process as CrO3, Cr2O3, and CrNbO4, while nickel dissolved only as NiO in the system. Formation of a porous and nonprotective oxide layer with low resistance is responsible for the weak protective properties of the barrier layer at high temperatures of 973 K and 1073 K (700 °C and 800 °C). There were two kinds of attack for INCONEL 625, including general surface corrosion and pitting. Pitting corrosion occurred due to the breakdown of the initial oxide layer by molten salt dissolution of the oxide or oxide cracking.

  4. Effect of cooling rate on the transition temperature in Bi-Pb-Sr-Ca-Cu-O system

    International Nuclear Information System (INIS)

    Wang Yugui; Wang Jinsong; Wang Nanlin; Jiao Xinping; Han Guchang; Chen Zhaojia; Wang Keqin; Wu Xiaoguang

    1989-12-01

    The resistance and a.c. susceptibility measurement show that cooling rate of the cast-annealing samples in heat treatment process has some effect on the 110K superconducting phase in Bi-Pb-Sr-Ca-Cu-O system. Rapid quenching of the sample in air from 845 deg C causes oxygen deficiency in lattice and brings about a trifling change of unit cell size along c-axis direction. The d.c. magnetization and specific heat anomaly Δc measurements demostrate that fast cooling rate can reduce the transition temperature of high-T c phase and the lower critical field, and weaken the pinning forces for vertex lines. The peak value of specific heat anomaly of the sample with nominal composition of Bi 1.7 Pb 0.3 Sr 2 Ca 2 Cu 4.5 O v is still small in comparison with YBa 2 Cu 3 O 7 . From the magnetization curve the authors estimate that the superconducting volume fraction is about 20%

  5. First-principles study for the enhanced sulfur tolerance of Ni(1 1 1) surface alloyed with Pb

    Science.gov (United States)

    Zhang, Yanxing; Yang, Zongxian

    2018-04-01

    The adsorption of H2S, HS, S, H and the dissociation of H2S on the Ni2Pb/Ni (1 1 1) are systematically studied using the first-principles method based on density functional theory. It is found that H2S dissociation barriers are greatly increased by alloying with Pb atoms in the Ni(1 1 1) surface, while the barrier for H2S formation is greatly reduced. In addition, the adsorption of sulfur atom is weakened a lot. The results indicate that alloying with Pb may be a good way to increase the sulfur tolerance of Ni based anode catalysts of solid oxide fuel cells.

  6. Quantification of the 214 Pb and 214 Bi decay products before and after to reach the secular equilibria with the 226 Ra

    International Nuclear Information System (INIS)

    Quintero P, E.; Rojas M, V.P.; Cervantes N, M.L.; Gaso P, M.I.

    2002-01-01

    In this work a comparison between the 226 Ra concentration and its decay products ( 214 Pb and 214 Bi) in soil samples is presented before and after that the decay mentioned products reach the equilibria with the radium. Moreover, the obtained daughter/father ratio is presented; and the correction factor for the calculus of the 214 Pb and 214 Bi quantification without being necessary to wait until that the secular equilibria has been established. For the quantification of the concentration of the three radionuclides the gamma spectrometry technique was used. (Author)

  7. Evaporation Behavior and Characterization of Eutectic Solvent and Ibuprofen Eutectic Solution.

    Science.gov (United States)

    Phaechamud, Thawatchai; Tuntarawongsa, Sarun; Charoensuksai, Purin

    2016-10-01

    Liquid eutectic system of menthol and camphor has been reported as solvent and co-solvent for some drug delivery systems. However, surprisingly, the phase diagram of menthol-camphor eutectic has not been reported previously. The evaporation behavior, physicochemical, and thermal properties of this liquid eutectic and ibuprofen eutectic solution were characterized in this study. Differential scanning calorimetry (DSC) analysis indicated that a eutectic point of this system was near to 1:1 menthol/camphor and its eutectic temperature was -1°C. The solubility of ibuprofen in this eutectic was 282.11 ± 6.67 mg mL(-1) and increased the drug aqueous solubility fourfold. The shift of wave number from Fourier transform infrared spectroscopy (FTIR) indicated the hydrogen bonding of each compound in eutectic mixture. The weight loss from thermogravimetric analysis of menthol and camphor related to the evaporation and sublimation, respectively. Menthol demonstrated a lower apparent sublimation rate than camphor, and the evaporation rate of eutectic solvent was lower than the sublimation rate of camphor but higher than the evaporation of menthol. The evaporation rate of the ibuprofen eutectic solution was lower than that of the eutectic solvent because ibuprofen did not sublimate. This eutectic solvent prolonged the ibuprofen release with diffusion control. Thus, the beneficial information for thermal behavior and related properties of eutectic solvent comprising menthol-camphor and ibuprofen eutectic solution was attained successfully. The rather low evaporation of eutectic mixture will be beneficial for investigation and tracking the mechanism of transformation from nanoemulsion into nanosuspension in the further study using eutectic as oil phase.

  8. The creep-rupture behaviour of the martensitic steel X18CrMoVNb 121 (no.1.4914) in liquid Pb-17 Li at 550 and 6000C

    International Nuclear Information System (INIS)

    Grundmann, M.; Borgstedt, H.U.; Schirra, M.

    1988-01-01

    One of the candidate structural materials for the NET blanket is the martensitic steel X18 CrMoVNb 12 1 (no.1.4914). Its compatibility with the molten eutectic Pb-17Li, which might be used as liquid breeder and coolant in a self-cooled liquid metal blanket, should be satisfying even under superimposed mechanical stress. The mechanical high-temperature strength of the steel should not be significantly reduced by the interaction with the liquid metal which is in close contact with the surface of the components of such a blanket. The corrosion behaviour of this steel in flowing Pb-17Li eutectic is also studied, results will be presented at this conference. A certain influence of a liquid metal environment on the creep-rupture behaviour of steels was observed earlier in a study on the mechanical properties of austenitic stainless steel in liquid sodium. Therefore, a test programme was initiated to evaluate the effects of liquid Pb-17Li alloy on the creep strength of the steel no. 1.4914. Liquid lithium environment showed an influence on the fracture of this material in short time tests at moderate temperature

  9. L-shell ionization studies of Pb and Bi with α particles

    International Nuclear Information System (INIS)

    Dhal, B.B.; Nandi, T.; Padhi, H.C.

    1994-01-01

    Ionization cross sections for the L subshells of Pb and Bi by α-particle bombardment (2.2--8.2 MeV) have been determined from the experimental data and the currently available radiative transition probabilities, fluorescence yields, and Coster-Kronig factors. The measured ionization cross sections and their ratios are compared with the results of ECPSSR calculations [ECPSSR denotes perturbed-stationary-state (PSS) theory with energy-loss (E), Coulomb deflection (C), and relativistic (R) corrections]. The measured individual cross sections for L 1 and L 2 subshells deviated in opposite directions from the theory, whereas their sum shows good agreement. The L 3 and total ionization cross sections obtained from the data also show good agreement with the ECPSSR theory. The ionization cross-section ratios σ L1 /σ L2 and σ L3 /σ L2 show large deviations from the ECPSSR theory. The experimental x-ray production cross-section ratios are found to be in better agreement with the theoretical results obtained from using ECPSSR ionization cross sections and the decay yield data of Xu and Xu [J. Phys. B 25, 695 (1992)] rather than those obtained from using the decay yield data of Krause [J. Phys. Chem. Ref. Data 8, 307 (1979)]. The x-ray production cross sections, however, are in better agreement with the theoretical results obtained from using the decay yield data of Krause. The measured centroid energy of the Lγ lines of Pb shows large deviations at high projectile energy, whereas for Bi large deviations are found at the low-energy region

  10. Study on borate glass system containing with Bi2O3 and BaO for gamma-rays shielding materials: Comparison with PbO

    International Nuclear Information System (INIS)

    Kaewkhao, J.; Pokaipisit, A.; Limsuwan, P.

    2010-01-01

    In this work, the mass attenuation coefficients and shielding parameters of borate glass matrices containing with Bi 2 O 3 and BaO have been investigated at 662 keV, and compare with PbO in same glass structure. The theoretical values were calculated by WinXCom software and compare with experiential data. The results found that the mass attenuation coefficients were increased with increasing of Bi 2 O 3 , BaO and PbO concentration, due to increase photoelectric absorption of all glass samples. However, Compton scattering gives dominant contribution to the total mass attenuation coefficients for studied glass samples. Moreover the half value layers (HVL) of glass samples were also better than ordinary concretes and commercial window glass. These results reflecting that the Bi-based glass can use replace Pb in radiation shielding glass. In the case of Ba, may be can use at appropriate energy such as X-rays or lower.

  11. Influence of bismuth on the age-hardening and corrosion behaviour of low-antimony lead alloys in lead/acid battery systems

    Energy Technology Data Exchange (ETDEWEB)

    Lam, L.T. [CSIRO, Div. of Mineral Products, Port Melbourne, VIC (Australia); Huynh, T.D. [CSIRO, Div. of Mineral Products, Port Melbourne, VIC (Australia); Haigh, N.P. [CSIRO, Div. of Mineral Products, Port Melbourne, VIC (Australia); Douglas, J.D. [CSIRO, Div. of Mineral Products, Port Melbourne, VIC (Australia); Rand, D.A.J. [CSIRO, Div. of Mineral Products, Port Melbourne, VIC (Australia); Lakshmi, C.S. [Pasminco Research Centre, Boolaroo, NSW (Australia); Hollingsworth, P.A. [Pasminco Research Centre, Boolaroo, NSW (Australia); See, J.B. [Pasminco Research Centre, Boolaroo, NSW (Australia); Manders, J. [Pasminco Ltd., Melbourne, VIC (Australia); Rice, D.M. [Pasminco Ltd., Melbourne, VIC (Australia)

    1995-01-01

    The effects of bismuth additions in the range 0.006-0.086 wt.% on the metallurgical and electrochemical properties of Pb-1.5 wt.% Sb alloy are investigated. The self-discharge behaviour of batteries produced with grids of the doped alloys is also evaluated. Addition of bismuth is found to exert no significant effects on the age-hardening behaviour, general microstructure or grain size of the alloy. It does, however, influence the morphology of the eutectic in the inter-dendritic regions. The latter changes from a mainly lamellar to an irregular type with increasing bismuth content. The corrosion rate of the grid decreases with increase of the bismuth content. Attack occurs preferentially in the inter-dendritic regions where there is an enrichment of both antimony and bismuth. Electron-probe microanalysis shows that the corrosion zone consists of a tri-layered structure, namely: a dense, continuous, inner layer (PbO{sub 1.1}); a central layer (PbO{sub 1.8}.PbSO{sub 4}); a porous outer layer n(PbO{sub 1.8}).PbSO{sub 4}, with n=2-8. In the latter, the value of n increases in the direction of corrosive penetration into the grid. Data from atomic absorption spectrometric analysis reveal that bismuth, after oxidative leaching from the grid substrate, is retained mainly in the corrosion layer. A key observation is that bismuth (i.e., up to {approx}0.09 wt.%) does not affect the self-discharge behaviour of batteries. (orig.)

  12. Fluctuation Induced Conductivity Studies of 100 MeV Oxygen Ion Irradiated Pb Doped Bi-2223 Superconductors

    NARCIS (Netherlands)

    Banerjee, Tamalika; Kumar, Ravi; Kanjilal, D.; Ramasamy, S.

    2000-01-01

    We report on 100 MeV oxygen ion irradiation in Pb doped Bi-2223 superconductors. Resistivity measurements reveal that both grains as well as the grain boundaries are affected by such irradiation. An analysis of the excess conductivity has been made within the framework of Aslamazov-Larkin (AL) and

  13. MHD PbLi experiments in MaPLE loop at UCLA

    International Nuclear Information System (INIS)

    Courtessole, C.; Smolentsev, S.; Sketchley, T.; Abdou, M.

    2016-01-01

    Highlights: • The paper overviews the MaPLE facility at UCLA: one-of-a-few PbLi MHD loop in the world. • We present the progress achieved in development and testing of high-temperature PbLi flow diagnostics. • The most important MHD experiments carried out since the first loop operation in 2011 are summarized. - Abstract: Experiments on magnetohydrodynamic (MHD) flows are critical to understanding complex flow phenomena in ducts of liquid metal blankets, in particular those that utilize eutectic alloy lead–lithium as breeder/coolant, such as self-cooled, dual-coolant and helium-cooled lead–lithium blanket concepts. The primary goal of MHD experiments at UCLA using the liquid metal flow facility called MaPLE (Magnetohydrodynamic PbLi Experiment) is to address important MHD effects, heat transfer and flow materials interactions in blanket-relevant conditions. The paper overviews the one-of-a-kind MaPLE loop at UCLA and presents recent experimental activities, including the development and testing of high-temperature PbLi flow diagnostics and experiments that have been performed since the first loop operation in 2011. We also discuss MaPLE upgrades, which need to be done to substantially expand the experimental capabilities towards a new class of MHD flow phenomena that includes buoyancy effects.

  14. MHD PbLi experiments in MaPLE loop at UCLA

    Energy Technology Data Exchange (ETDEWEB)

    Courtessole, C., E-mail: cyril@fusion.ucla.edu; Smolentsev, S.; Sketchley, T.; Abdou, M.

    2016-11-01

    Highlights: • The paper overviews the MaPLE facility at UCLA: one-of-a-few PbLi MHD loop in the world. • We present the progress achieved in development and testing of high-temperature PbLi flow diagnostics. • The most important MHD experiments carried out since the first loop operation in 2011 are summarized. - Abstract: Experiments on magnetohydrodynamic (MHD) flows are critical to understanding complex flow phenomena in ducts of liquid metal blankets, in particular those that utilize eutectic alloy lead–lithium as breeder/coolant, such as self-cooled, dual-coolant and helium-cooled lead–lithium blanket concepts. The primary goal of MHD experiments at UCLA using the liquid metal flow facility called MaPLE (Magnetohydrodynamic PbLi Experiment) is to address important MHD effects, heat transfer and flow materials interactions in blanket-relevant conditions. The paper overviews the one-of-a-kind MaPLE loop at UCLA and presents recent experimental activities, including the development and testing of high-temperature PbLi flow diagnostics and experiments that have been performed since the first loop operation in 2011. We also discuss MaPLE upgrades, which need to be done to substantially expand the experimental capabilities towards a new class of MHD flow phenomena that includes buoyancy effects.

  15. Formation of Ag nanoparticles in percolative Ag–PbTiO3 composite thin films through lead-rich Ag–Pb alloy particles formed as transitional phase

    International Nuclear Information System (INIS)

    Hu, Tao; Wang, Zongrong; Su, Yanbo; Tang, Liwen; Shen, Ge; Song, Chenlu; Han, Gaorong; Weng, Wenjian; Ma, Ning; Du, Piyi

    2012-01-01

    The Ag nanoparticle dispersed percolative PbTiO 3 ceramic thin film was prepared in situ by sol–gel method with excess lead introduced into a sol precursor. The influence of excess lead and the heat treatment time on the formation of Ag nanoparticles was investigated by energy dispersive X-ray spectra, scanning electron microscopy, X-ray diffraction, and ultraviolet–visible absorption spectra. Results showed that the excess lead introduced into the sol precursor was in favor of the crystallization of the thin film and in favor of formation of the perovskite phase without the pyrochlore phase. Lead-rich Ag–Pb alloy particles first formed in the thin films and then decomposed to become large numbers of Ag nanoparticles of about 3 nm in size in the thin films when the heat treatment time was longer than 2 min. The content of the Ag nanoparticles increased with increasing the heat treatment time. The percolative behavior appears typically in the Ag nanoparticle dispersed thin films. The dielectric constant of the thin film was about 3 times of that without Ag nanoparticles. - Highlights: ► The Ag nanoparticles formed in the PbTiO 3 percolative ceramic thin film. ► The Ag–Pb alloy particles formed as transitional phase during thin film preparation. ► The lead-rich Ag–Pb alloy particles decomposed to form Ag nanoparticles in the film. ► Permittivity of the thin film is 3 times higher than that without Ag nanoparticles.

  16. Deformation of superplastic alloys at relatively low strain rates

    International Nuclear Information System (INIS)

    Grivas, D.

    1978-02-01

    The superplastic and sub-superplastic creep properties of Pb-Sn eutectic and Al-Zn eutectoid alloys were studied. Various thermomechanical treatments we tested to check the possibilities of whether the subsuperplastic deformation mechanism is affected by these treatments. All thermomechanical histories were found to reveal the same stress exponent, which is believed to be indicative of the predominant mechanism. The mechanical data in the low stress region lead us to suggest that dislocation glide is the predominant mechanism in this region. At higher stresses extensive grain boundary sliding takes place and the dislocation movement is directed to relieve the stress concentration developed by the grain movement

  17. Interfacial microstructure and joining properties of Titanium–Zirconium–Molybdenum alloy joints brazed using Ti–28Ni eutectic brazing alloy

    Energy Technology Data Exchange (ETDEWEB)

    Song, X.G., E-mail: songxg@hitwh.edu.cn [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Shandong Provincial Key Lab of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209 (China); Tian, X. [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Shandong Provincial Key Lab of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209 (China); Zhao, H.Y. [Shandong Provincial Key Lab of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209 (China); Si, X.Q.; Han, G.H.; Feng, J.C. [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Shandong Provincial Key Lab of Special Welding Technology, Harbin Institute of Technology at Weihai, Weihai 264209 (China)

    2016-01-20

    Vacuum brazing of Titanium–Zirconium–Molybdenum (Abbreviated as TZM) alloy using Ti–28Ni (wt%) eutectic brazing alloy was successfully achieved in this study. Reliable TZM brazed joints were obtained at the temperatures ranging from 1000 °C to 1160 °C for 600 s. The interfacial microstructure of TZM joints was characterized by employing SEM, EDS and XRD. The effects of brazing temperature on interfacial microstructure and joining properties were investigated in details. TZM brazed joints mainly consisted of δ-Ti{sub 2}Ni phase and Ti-based solid solution (Ti(s,s)). The interfacial microstructure of TZM joints was influenced obviously by brazing temperature. Both the thickness of brazing seam and the amount of δ-Ti{sub 2}Ni phase was reduced with the increasing brazing temperature, while the Ti(s,s) layer did not change significantly. The maximum average shear strength of TZM joints reached 107 MPa when brazed at 1080 °C. The presence of δ-Ti{sub 2}Ni intermetallic phase and crack-like structure in joints deteriorated the joining properties, which resulted in the formation of brittle fracture after shear test. In addition, fracture locations were related to the brazing temperature. When the brazing temperature was relatively low, cracks initiated and propagated in the continuous δ-Ti{sub 2}Ni layer. However, the fracture locations preferred to locating at the interface between TZM substrate and brazing seam when brazing temperature exceeded 1080 °C.

  18. Effects of Electromagnetic Stirring on the Microstructure and High-Temperature Mechanical Properties of a Hyper-eutectic Al-Si-Cu-Ni Alloy

    Science.gov (United States)

    Jang, Youngsoo; Choi, Byounghee; Kang, Byungkeun; Hong, Chun Pyo

    2015-02-01

    A liquid treatment method by electromagnetic stirring was applied to a hyper-eutectic Al-15wt pctSi-4wt pctCu-3wt pctNi alloy for the piston manufacturing with diecasting process in order to improve high-temperature mechanical properties of the piston heads. The mechanical properties, such as hardness, high-temperature tensile stress, thermal expansion, and high-temperature relative wear resistance, were estimated using the specimens taken from the liquid-treated diecast products, and the results were compared with those of a conventional metal-mold-cast piston.

  19. Hydrogen storage properties of Mg-23.3wt.%Ni eutectic alloy prepared via hydriding combustion synthesis followed by mechanical milling

    International Nuclear Information System (INIS)

    Liquan Li; Yunfeng Zhu; Xiaofeng Liu

    2006-01-01

    A Mg-23.3wt.%Ni eutectic alloy was prepared by the process of hydriding combustion synthesis followed by mechanical milling (HCS+MM). The product showed a high hydriding rate at 373 K and the dehydrogenation started at temperature as low as 423 K. Several reasons contributing to the improvement in hydrogen storage properties were presented. The result of this study will provide attractive information for mobile applications of magnesium hydrogen storage materials, and the process of HCS+MM developed in this study showed its potential for synthesizing magnesium based hydrogen storage materials with novel hydriding/de-hydriding properties. (authors)

  20. Estimation of formation heat of rare earth and actinide alloys

    International Nuclear Information System (INIS)

    Shubin, A.B.; Yamshchikov, L.F.; Raspopin, S.P.

    1986-01-01

    A method for forecasting the enthalpy of formation of scandium, yttrium, lanthanum and lanthanides, thorium, uranium and plutonium alloys with a series of fusible metals (Al, Ga, In, Tl, Sn, Pb, Sb, Bi) is proposed. The obtained confidence internal value for the calculated Δ f H 0 values exceeds sufficiently the random error of the experimental determination of the rare metal alloy formation enthalpies. However, taking into account considerable divergences in results of Δ f H 0 determinations performed by different science groups, one may conclude, that such forecasting accuracy may be useful in the course of estimation calculations, especially, for actinide element alloys

  1. Analyzing power measurements for 209Bi(n,n) at 6 and 9 MeV and consistent dispersive optical-model analyses for n+209Bi and n+208Pb from -20 to +80 MeV

    International Nuclear Information System (INIS)

    Weisel, G.J.; Tornow, W.; Howell, C.R.; Felsher, P.D.; AlOhali, M.; Roberts, M.L.; Das, R.K.; Walter, R.L.; Mertens, G.

    1996-01-01

    High-accuracy measurements of A y (θ) data for elastic scattering for n+ 209 Bi have been performed at 6 and 9 MeV. The data are incorporated into a large database of σ(θ), A y (θ), and σ T for n+ 209 Bi covering the energy range 1.0 endash 80 MeV. A complementary database is constructed for n+ 208 Pb and a dispersive optical-model analysis is performed for both scattering systems while constraining many of the parameters to be identical for both systems. A good representation of both databases is obtained with conventional geometry and spin-orbit parameters. The 208 Pb model predicts quite well the measured energies of valence single-particle and single-hole bound states. Occupation probabilities and spectroscopic factors for the same bound states are also calculated. Finally, a fully constrained model is presented in which the only differences between the n+ 208 Pb and the n+ 209 Bi systems are the Fermi energy and the isospin dependence in the real volume potential. copyright 1996 The American Physical Society

  2. Study of fission reactions induced by 4,6He and 7Li beams on 209Bi and 208Pb targets

    Directory of Open Access Journals (Sweden)

    Lukyanov S.M.

    2013-12-01

    Full Text Available Study of fission reactions induced by 4,6He and 7Li beams on 209Bi and 208Pb targets, leading to the production of 210,212A compound nuclei, was performed. It was shown that the fission excitation functions for the three reactions 4,6He + 209Bi and 7Li + 208Pb had similar behavior within the experimental error for a broad range of energy. More likely, halo structure of 6He is not reflected on the fission reaction mechanism. Otherwise, a large value of the fusion cross section was observed so far, as it could be expected in the case of weakly bound character of 6He projectile.

  3. Microstructure and mechanical properties of Al-3Fe alloy processed by equal channel angular extrusion

    International Nuclear Information System (INIS)

    Fuxiao, Yu; Fang, Liu; Dazhi, Zhao; Toth, Laszlo S

    2014-01-01

    Al-Fe alloys are attractive for applications at temperatures beyond those normally associated with the conventional aluminum alloys. Under proper solidification condition, a full eutectic microstructure can be generated in Al-Fe alloys at Fe concentration well in excess of the eutectic composition of 1.8 wt.% Fe. The microstructure in this case is characterized by the metastable regular eutectic Al-Al 6 Fe fibers of nano-scale in diameter, instead of the equilibrium eutectic Al-Al 3 Fe phase. In this study, the microstructure and mechanical properties of the Al-3Fe alloy with metastable Al 6 Fe particles deformed by equal channel angular extrusion were investigated. Severe plastic deformation results in a microstructure consisting of submicron equiaxed Al grains with a uniform distribution of submicron Al 6 Fe particles on the grain boundaries. The room temperature tensile properties of the alloy with this microstructure will be presented

  4. Influence of transverse compressive stress on Ic degradation of Ag alloy sheathed Bi-2223 tapes

    International Nuclear Information System (INIS)

    Oh, S S; Ha, D W; Ha, H S; Park, C; Kwon, Y K; Ryu, K S; Shin, H S

    2004-01-01

    In order to investigate the degradation of critical current (I c ) in the Ag alloy sheathed Bi-2223 tapes due to a transverse compressive stress introduced during manufacturing and operation of the HTS systems, a sample holder consisting of the upper block made of Ti alloy and the lower support plate made of glass fibre reinforced plastic was prepared. A shorter spacing of voltage taps caused large degradation of critical current with respect to compressive stress. It was found that the extent of the I c degradation is proportional to the initial critical current density of the tapes. Through the experiment optimizing the shape of voltage terminals and the pressing load for the continuous contact type 4-probe I c measurement system, it was found that the conical shape tip with large curvature radius was effective in suppressing the I c degradation in Bi-2223 tapes during the I c measurement. A hard alloy sheath of Ag-0.6wt%Mn was found to be quite tolerant to the I c degradation against the pressing load of voltage terminals

  5. Microstructure investigation of NiAl-Cr(Mo) interface in a directionally solidified NiAl-Cr(Mo) eutectic alloyed with refractory metal

    International Nuclear Information System (INIS)

    Chen, Y.X.; Cui, C.Y.; Guo, J.T.; Li, D.X.

    2004-01-01

    The microstructure of a directionally solidified NiAl-Cr(Mo) eutectic alloyed with refractory metal in as-processed and heat-treated states has been studied by means of scanning electron microscopy and high resolution electron microscopy (HREM). The microstructure of the NiAl-Cr(Mo) eutectic was characterized by lamellar Cr(Mo) phases embedded within NiAl matrix with common growth direction of . The interface between NiAl and lamellar Cr(Mo) did not have any transition layers. Misfit dislocations were observed at the NiAl-Cr(Mo) interface. In addition to lamellar Cr(Mo) phases, coherent Cr(Mo, Ni, Al) precipitates and NiAl precipitates were also observed in the NiAl matrix and lamellar Cr(Mo) phases, respectively. After hot isostatic pressing and heat treatment, the NiAl-Cr(Mo) interfaces became smooth and straight. Square array of misfit dislocations was directly observed at the (0 0 1) interface between NiAl and Cr(Mo, Ni, Al) precipitate. The configuration of misfit dislocation network showed a generally good agreement with prediction based on the geometric O-lattice model

  6. High thermoelectric potential of Bi{sub 2}Te{sub 3} alloyed GeTe-rich phases

    Energy Technology Data Exchange (ETDEWEB)

    Madar, Naor; Givon, Tom; Mogilyansky, Dmitry; Gelbstein, Yaniv [Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel)

    2016-07-21

    In an attempt to reduce our reliance on fossil fuels, associated with severe environmental effects, the current research is focused on the identification of the thermoelectric potential of p-type (GeTe){sub 1−x}(Bi{sub 2}Te{sub 3}){sub x} alloys, with x values of up to 20%. Higher solubility limit of Bi{sub 2}Te{sub 3} in GeTe, than previously reported, was identified around ∼9%, extending the doping potential of GeTe by the Bi{sub 2}Te{sub 3} donor dopant, for an effective compensation of the high inherent hole concentration of GeTe toward thermoelectrically optimal values. Around the solubility limit of 9%, an electronic optimization resulted in an impressive maximal thermoelectric figure of merit, ZT, of ∼1.55 at ∼410 °C, which is one of the highest ever reported for any p-type GeTe-rich alloys. Beyond the solubility limit, a Fermi Level Pinning effect of stabilizing the Seebeck coefficient was observed in the x = 12%–17% range, leading to stabilization of the maximal ZTs over an extended temperature range; an effect that was associated with the potential of the governed highly symmetric Ge{sub 8}Bi{sub 2}Te{sub 11} and Ge{sub 4}Bi{sub 2}Te{sub 7} phases to create high valence band degeneracy with several bands and multiple hole pockets on the Fermi surface. At this compositional range, co-doping with additional dopants, creating shallow impurity levels (in contrast to the deep lying level created by Bi{sub 2}Te{sub 3}), was suggested for further electronic optimization of the thermoelectric properties.

  7. Physical properties of some Sn-based melts

    Directory of Open Access Journals (Sweden)

    Ilinykh N.

    2011-05-01

    Full Text Available The physical properties (viscosity, density, electroresistivity and magnetic susceptibility of pure tin, copper, silver, some binary (Sn - Ag, Sn - Cu, Sn - Bi, Sn - Zn and ternary (Sn-Ag-Cu, Sn-BiAg, Sn-Bi-Zn alloys with near eutectic compositions are investigated in wide temperature ranges. The irreversible decrease of viscosity in pure tin melt is discovered at 820 °С during heating. The similar anomaly with the following hysteresis of dynamic viscosity was fixed for binary and ternary alloys but at higher temperatures – 900 °С and 950 °С respectively. For all the systems it was shown that the alloys with eutectic compositions differ significantly in their electric and magnetic properties from hypo- and hypereutectic ones. Qualitative and quantitative metallographic analysis for Sn-3.8wt.%Ag-0.7wt.%Cu samples, heated low and above characteristic temperatures, showed the influence of melt overheating on crystallization kinetics.

  8. Influence of aging treatment on deformation behavior of 96.5Sn3.5Ag lead-free solder alloy during in situ tensile tests

    International Nuclear Information System (INIS)

    Ding, Ying; Wang, Chunqing; Tian, Yanhong; Li, Mingyu

    2007-01-01

    This study investigates the influence of aging treatment on deformation behavior of 96.5Sn3.5Ag eutectic solder alloys with lower strain rate ( -3 s -1 ) during tensile tests under the scanning electron microscope. Results showed that because of the existence of Ag 3 Sn intermetallic particles and the special microstructure of β-Sn phases in Sn3.5Ag solder, grain boundary sliding was not the dominant mechanism any longer for this Pb-free solder. While the interaction of dislocations with the relatively rigid Ag 3 Sn particles began to dominate. For the as-cast specimen, accompanied by partial intragranular cracks, intergranular fracture along the grain boundaries in Sn-Ag eutectic structure or the interphase boundaries between Sn-rich dendrites and Sn-Ag eutectic phases occurred primarily in early tensile stage. However, the boundary behavior was limited by the large Ag 3 Sn particles presented along the Sn-rich dendrites boundaries after aging. Plastic flow was observed in large area, and cracks propagated in a transgranular manner across the Sn-dendrites and Sn-Ag eutectic structure

  9. High-density Bi-Pb-Sr-Ca-Cu-O superconductor prepared by rapid thermal melt processing

    Science.gov (United States)

    Moon, B. M.; Lalevic, B.; Kear, B. H.; McCandlish, L. E.; Safari, A.; Meskoob, M.

    1989-10-01

    A high quality, dense Bi-Pb-Sr-Ca-Cu-O superconductor has been successfully synthesized by rapid thermal melt processing. Conventionally sintered pellets were melted at 1200 °C, cooled rapidly, and then annealed. As-melted samples exhibited semiconductor behavior, which upon annealing became superconducting at 115 K [Tc(zero)=105 K]. A detailed study of various processing techniques has been carried out.

  10. Safety performance comparation of MOX, nitride and metallic fuel based 25-100 MWe Pb-Bi cooled long life fast reactors without on-site refuelling

    International Nuclear Information System (INIS)

    Su'ud, Zaki

    2008-01-01

    In this paper the safety performance of 25-100 MWe Pb-Bi cooled long life fast reactors based on three types of fuels: MOX, nitride and metal is compared and discussed. In the fourth generation NPP paradigm, especially for Pb-Bi cooled fast reactors, inherent safety capability is necessary against some standard accidents such as unprotected loss of flow (ULOF), unprotected rod run-out transient over power (UTOP), unprotected loss of heat sink (ULOHS). Selection of fuel type will have important impact on the overall system safety performance. The results of safety analysis of long life Pb-Bi cooled fast reactors without on-site fuelling using nitride, MOX and metal fuel have been performed. The reactors show the inherent safety pattern with enough safety margins during ULOF and UTOP accidents. For MOX fuelled reactors, ULOF accident is more severe than UTOP accident while for nitride fuelled cores UTOP accident may push power much higher than that comparable MOX fuelled cores. (author)

  11. Evolution of thermoelectric performance for (Bi,Sb)2Te3 alloys from cutting waste powders to bulks with high figure of merit

    International Nuclear Information System (INIS)

    Fan, Xi'an; Cai, Xin zhi; Han, Xue wu; Zhang, Cheng cheng

    2016-01-01

    Bi 2 Te 3 based cutting waste powders from cutting wafers were firstly selected as raw materials to prepare p-type Bi 2 Te 3 based thermoelectric (TE) materials. Through washing, reducing, composition correction, smelting and resistance pressing sintering (RPS) process, p-type (Bi,Sb) 2 Te 3 alloy bulks with different nominal stoichiometries were successfully obtained. The evolution of microstructure and TE performance for (Bi,Sb) 2 Te 3 alloys were investigated in detail. All evidences confirmed that most of contaminants from line cutting process such as cutting fluid and oxides of Bi, Sb or Te could be removed by washing, reducing and smelting process used in this work. The carrier content and corresponding TE properties could be adjusted effectively by appropriate composition correction treatment. At lastly, a bulk with a nominal stoichiometry of Bi 0.44 Sb 1.56 Te 3 was obtained and its' dimensionless figure of merit (ZT) was about 1.16 at 90 °C. The ZT values of Bi 0.36 Sb 1.64 Te 3 and Bi 0.4 Sb 1.6 Te 3 alloy bulks could also reach 0.98 and 1.08, respectively. Different from the conventional recycling technology such as hydrometallurgy extraction methods, the separation and extraction of beneficial elements such as Bi, Sb and Te did not need to be performed and the Bi 2 Te 3 based bulks with high TE properties could be directly obtained from the cutting waste powders. In addition, the recycling technology introduced here was green and more suitable for practical industrial application. It can improve material utilization and lower raw material costs of manufacturers. - Graphical abstract: Three kinds of typical morphologies for the fractographs: typical lamellar structure, agglomerated submicron-sized granules and dispersed cubic particles from the initial cutting waste powders. - Highlights: • Bi 2 Te 3 based wastes were directly selected as raw materials for TE alloys. • Contaminants from cutting fluid and oxides could be effectively removed.

  12. Effect of stress on the superconducting transition temperature in indium, indium-alloy, tin, and tin-alloy whisker samples

    International Nuclear Information System (INIS)

    Cook, J.W. Jr.; Davis, W.T.; Chandler, J.H.; Skove, M.J.

    1977-01-01

    The dependence of the superconducting transition temperature (T/sub c/) on stress (sigma) for pure In and Sn samples was found to be in qualitative agreement with earlier work. For convenience T/sub c/ is expressed as a function of the experimentally measured strain (epsilon), which is proportional to sigma. The effect of alloying on the initial dependence of the T/sub c/-vs-epsilon curves, (per. delta T/sub c//per. delta epsilon)/sub epsilon = 0/ = eta, was quite different for the In and Sn alloys. The In samples were alloyed with a maximum of 4.8 at.% Tl, 7.9 at.% Sn, and 6.7 at.% Pd; the Sn samples were alloyed with a maximum of 0.3 at.% Cd, 6.0 at.% In, 0.3 at.% Sb, and 2.2 at.% Bi. The addition of impurities had a large effect on eta for the In alloys, with eta reversing sign for some Sn and Pb alloy contents (chi). The T/sub c/-vs-epsilon curves also became nonlinear for some chi. The possible relationship of the In alloy results to changes in the Fermi surface due to the addition of impurities is discussed. For the Sn alloy samples, there was no change in eta with any impurity. The change in room-temperature resistivity with strain was also measured. There was only a slight decrease in the dependence of resistivity on strain for the In--Sn and In--Pb data and no effect on the In--Tl or Sn alloy data

  13. Evolution of thermoelectric performance for (Bi,Sb)2Te3 alloys from cutting waste powders to bulks with high figure of merit

    Science.gov (United States)

    Fan, Xi‧an; Cai, Xin zhi; Han, Xue wu; Zhang, Cheng cheng; Rong, Zhen zhou; Yang, Fan; Li, Guang qiang

    2016-01-01

    Bi2Te3 based cutting waste powders from cutting wafers were firstly selected as raw materials to prepare p-type Bi2Te3 based thermoelectric (TE) materials. Through washing, reducing, composition correction, smelting and resistance pressing sintering (RPS) process, p-type (Bi,Sb)2Te3 alloy bulks with different nominal stoichiometries were successfully obtained. The evolution of microstructure and TE performance for (Bi,Sb)2Te3 alloys were investigated in detail. All evidences confirmed that most of contaminants from line cutting process such as cutting fluid and oxides of Bi, Sb or Te could be removed by washing, reducing and smelting process used in this work. The carrier content and corresponding TE properties could be adjusted effectively by appropriate composition correction treatment. At lastly, a bulk with a nominal stoichiometry of Bi0.44Sb1.56Te3 was obtained and its' dimensionless figure of merit (ZT) was about 1.16 at 90 °C. The ZT values of Bi0.36Sb1.64Te3 and Bi0.4Sb1.6Te3 alloy bulks could also reach 0.98 and 1.08, respectively. Different from the conventional recycling technology such as hydrometallurgy extraction methods, the separation and extraction of beneficial elements such as Bi, Sb and Te did not need to be performed and the Bi2Te3 based bulks with high TE properties could be directly obtained from the cutting waste powders. In addition, the recycling technology introduced here was green and more suitable for practical industrial application. It can improve material utilization and lower raw material costs of manufacturers.

  14. Rapid formation of the 110 K phase in Bi-Pb-Sr-Ca-Cu-O through freeze-drying powder processing

    International Nuclear Information System (INIS)

    Song, K.H.; Liu, H.K.; Dou, S.X.; Sorrell, C.C.

    1990-01-01

    This paper reports three techniques for processing Bi-Pb-Sr-Ca-Cu-O (BPSCCO) powders investigated: dry-mixing, sol-gel formation, and freeze-drying. It was found that sintering for 120 h at 850 degrees C is required to form nearly single-phase (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10-y by dry-mixing, whereas sintering for 30 h at 840 degrees C was sufficient to form the 110 K (2223) phase when freeze-drying was used. The sol-gel route was found to be intermediate in efficiency between these two techniques. Freeze-drying provided highly reactive, intimately mixed, and carbon-free precursors. The presence of carbonates in the uncalcined powders was the major cause of phase segregation and sluggishness of the 110 K phase formation

  15. Electrical and optical properties of thin films with a SnS{sub 2} - Bi{sub 2}S{sub 3} alloy grown by sulphurization

    Energy Technology Data Exchange (ETDEWEB)

    Dussan, A; Mesa, F; Gordillo, G [Departamento de Fisica, Universidad Nacional de Colombia, Bogota Cr.30 No 45-03 (Colombia); Botero, M, E-mail: ggordillog@unal.edu.c, E-mail: adussanc@unal.edu.c [Departamento de Fisica, Universidad Central, Bogota Cr.5 No 21A-03 (Colombia)

    2009-05-01

    In this work, thin films of SnS{sub 2} with increased Bi content were grown by sulphurization of a thin film of Sn:Bi alloy, at temperatures around 300{sup 0}C. The effect of the Bi concentration on the optical, electrical and structural properties was determined through measurements of spectral transmittance, conductivity and x-ray diffraction XRD respectively. It was found that the optical constants (refractive index n, absorption coefficient alpha and energy gap Eg) and the electrical conductivity are significantly affected by the Bi concentration. In particular, a variation of the energy gap between 1.44 and 1.63 eV and a change of the conductivity greater than three orders of magnitude were observed when the content of Bi in the Sn:Bi alloy varied between 0 and 100 %. The analysis of the XRD measurements allowed us to find that the SnS: Bi films grow with a mixture of the SnS{sub 2} and Bi{sub 2}S{sub 3} phases, independently of the Bi content.

  16. Experimental Cross Sections for Reactions of Heavy Ions and 208Pb, 209Bi, 238U, and 248Cm Targets

    International Nuclear Information System (INIS)

    Patin, Joshua B.

    2002-01-01

    The study of the reactions between heavy ions and 208 Pb, 209 Bi, 238 U, and 248 Cm targets was performed to look at the differences between the cross sections of hot and cold fusion reactions. Experimental cross sections were compared with predictions from statistical computer codes to evaluate the effectiveness of the computer code in predicting production cross sections. Hot fusion reactions were studied with the MG system, catcher foil techniques and the Berkeley Gas-filled Separator (BGS). 3n- and 4n-exit channel production cross sections were obtained for the 238 U( 18 O,xn) 256-x Fm, 238 U( 22 Ne,xn) 260-x No, and 248 Cm( 15 N,xn) 263-x Lr reactions and are similar to previous experimental results. The experimental cross sections were accurately modeled by the predictions of the HIVAP code using the Reisdorf and Schaedel parameters and are consistent with the existing systematics of 4n exit channel reaction products. Cold fusion reactions were examined using the BGS. The 208 Pb( 48 Ca,xn) 256-x No, 208 Pb( 50 Ti,xn) 258-x Rf, 208 Pb( 51 V,xn) 259-x Db, 209 Bi( 50 Ti,xn) 259-x Db, and 209 Bi( 51 V,xn) 260-x Sg reactions were studied. The experimental production cross sections are in agreement with the results observed in previous experiments. It was necessary to slightly alter the Reisdorf and Schaedel parameters for use in the HIVAP code in order to more accurately model the experimental data. The cold fusion experimental results are in agreement with current 1n- and 2n-exit channel systematics

  17. Study of current-voltage characteristics in PbTe(Ga) alloys at low temperatures

    International Nuclear Information System (INIS)

    Akimov, B.A.; Albul, A.V.; Bogdanov, E.V.

    1992-01-01

    Results of determining current-voltage characteristics in PbTe(Ga) monocrystals of n- and p-types of conductivity in strong electric fields E ≤ 2 x 10 3 V/Cm at 4.2-77 K are presented. It was established that at helium and nitrogen temperatures, the current-voltage characteristics of PbTe(Ga) alloys, high-ohmic state of which was realized in helium, differed qualitatively from ones, typical for unalloyed PbTe. The superlinear dependence, observed in the fields, beginning from E ≥ 1 V/cm, is explained in the framework of concepts of strong electric field effect on conductivity of impurity states

  18. Finite Element-Assisted Assessment of the Thermo-cyclic Characteristics of Leads Soldered with SnAgCu(+Bi,In) Alloys

    Science.gov (United States)

    Lis, Adrian; Nakanishi, Kohei; Matsuda, Tomoki; Sano, Tomokazu; Minagawa, Madoka; Okamoto, Masahide; Hirose, Akio

    2017-07-01

    Solder joints between leads and printed circuit boards in thin small outline packages were produced with conventional Sn1.0Ag0.7Cu (SAC107) and Sn3.0Ag0.7Cu (SAC305) solders as well as various solder alloys with gradually increasing amounts of Bi (up to 3.0 wt.%) and In (up to 1.0 wt.%) within the SAC107 base solder. The reliability of soldered leads in temperature cycle (TC) tests improved most with solder alloys containing both Bi (1.6 wt.%) and In (0.5 wt.%). Microindentation and electron probe microanalysis mappings revealed that the effect originates from a combination of solution and precipitation strengthening of the initial SAC alloy. The distribution of inelastic strain accumulation (ISA), as a measure for degradation, was determined in the solder joints by finite element calculations. It was shown that defects in the solder proximal to the lead (60-75 μm), which was underpinned by similar cracking characteristics along the lead-solder interface. The ISA was confirmed to be lower in SAC+Bi/In alloys owing to their enhanced elasto-plastic properties. Moreover, the addition of a thin Cu coating on the leads could improve the joint reliability, as suggested by the calculation of the ISA and the acceleration factor.

  19. Structure of the displacement field of substitutionally dissolved Bi in Pb

    International Nuclear Information System (INIS)

    Seitz, E.

    1975-03-01

    In order to describe measurements of the coherent diffuse scattering of neutrons from Pb-Bi within the single defect approximation, Schumacher (1969) introduced a model in which the displacement field of the host lattice caused by a given Bismuth atom has trigonal symmetry. In an attempt to decide which model for the displacement field is correct, new measurements over an extended range were carried out with an improved resolution, using the D7 diffractometer at the High Flux Reactor in Grenoble. Taking the different resolutions into account, agreement between the present and previous data is good, both as to absolute intensity and scattering pattern. (orig./HPoe) [de

  20. High-pressure anisotropic distortion of Pb3Bi2S6

    DEFF Research Database (Denmark)

    Olsen, Lars Arnskov; Balic Zunic, Tonci; Makovicky, Emil

    2008-01-01

    The compound Pb3Bi2S6 is investigated by X-ray diffraction on single crystals in a diamond-anvil cell between 0.0001 and 10.5 GPa. It undergoes a first-order phase transition at hydrostatic pressure between 3.7 and 4.9 Gpa. The space group symmetry changes from Bbmm to Pbnm, and the unit......-cell volume decreases by 4%. The transition is strongly anisotropic, with a contraction along one of the crystal axes by 16% and expansion along another one by 14%. This is a piezoplastic phase transition, a displacive pressure-induced phase transition with systematic shearing of atomic planes and a migration...

  1. Quantification of the {sup 214} Pb and {sup 214} Bi decay products before and after to reach the secular equilibria with the {sup 226} Ra; Cuantificacion de los productos de decaimiento {sup 214} Pb y {sup 214} Bi antes y despues de alcanzar el equilibrio secular con el {sup 226} Ra

    Energy Technology Data Exchange (ETDEWEB)

    Quintero P, E.; Rojas M, V.P.; Cervantes N, M.L.; Gaso P, M.I. [Gerencia de Seguridad Radiologica, ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2002-07-01

    In this work a comparison between the {sup 226} Ra concentration and its decay products ({sup 214} Pb and {sup 214} Bi) in soil samples is presented before and after that the decay mentioned products reach the equilibria with the radium. Moreover, the obtained daughter/father ratio is presented; and the correction factor for the calculus of the {sup 214} Pb and {sup 214} Bi quantification without being necessary to wait until that the secular equilibria has been established. For the quantification of the concentration of the three radionuclides the gamma spectrometry technique was used. (Author)

  2. Separation of 210 Pb, 210 Bi and 210 Po by ion exchange and their liquid scintillation standardization

    International Nuclear Information System (INIS)

    Rodriguez, L.; Jimenez, A.; Grau, A.

    1996-01-01

    We applied the CIEMAT/NIST method and alpha/beta discrimination to ''210 Pb samples in equilibrium with its daughters, by preparing homogeneous and gel samples. The stability of samples was tested in different available cocktails, HiSafe''tm II, HiSafe''tmIII, Ultima-Gold''tm, Ultima-Gold''tmXR, Ultima-Gold''tmAB, Insta-Gel and e Insta-Gel II. Also we analyzed the disequilibrium of the radioactive chain ''210Pb+''210Bi+''210Po, achieving and excellent agreement between the results of the spectrum unfolding method and the experimental values. (Author) 13 refs

  3. Effect of Pb and Ag additions on electrical properties Bi2Sr2Ca2Cu3Ox superconductive ceramics

    International Nuclear Information System (INIS)

    Reddi, B.V.; Uskov, E.M.

    1990-01-01

    The influence of Pb and Ag additions on the electrical properties of Bi 2 Sr 2 Ca 2 Cu 3 O x superconducting ceramics has been studied by Hall method. It was found that the Pb additions has more influence on the sample characteristics than Ag. It was found, that Hall EMF at 77 K equal to zero in the samples having some residue resistance

  4. Effect of bismuth and silver on the corrosion behavior of Sn-9Zn alloy in NaCl 3 wt.% solution

    Energy Technology Data Exchange (ETDEWEB)

    Ahmido, A. [Laboratory of Chimie Physique General, Faculty of Sciences, University Med V Agdal, Av. Ibn Battouta, B.P. 1014, M-10000 Rabat (Morocco); Laboratory of Spectroscopy Infra Rouge, Faculty of Sciences, University Med V Agdal, Av. Ibn Battouta, B.P. 1014, M-10000 Rabat (Morocco); Sabbar, A. [Laboratory of Chimie Physique General, Faculty of Sciences, University Med V Agdal, Av. Ibn Battouta, B.P. 1014, M-10000 Rabat (Morocco); Zouihri, H.; Dakhsi, K. [UATRS, CNRST, Angle Allal Fassi, FAR, BP 8027, Hay Riad, Rabat (Morocco); Guedira, F. [Laboratory of Chimie Physique General, Faculty of Sciences, University Med V Agdal, Av. Ibn Battouta, B.P. 1014, M-10000 Rabat (Morocco); Serghini-Idrissi, M. [Laboratory of Spectroscopy Infra Rouge, Faculty of Sciences, University Med V Agdal, Av. Ibn Battouta, B.P. 1014, M-10000 Rabat (Morocco); El Hajjaji, S., E-mail: selhajjaji@hotmail.com [Laboratory of Spectroscopy Infra Rouge, Faculty of Sciences, University Med V Agdal, Av. Ibn Battouta, B.P. 1014, M-10000 Rabat (Morocco)

    2011-08-15

    Highlights: > Sn-9Zn-xAg-yBi as alternative for Sn-Pb solder. > Effect of silver (Ag) and bismuth (Bi) on the corrosion resistance of Sn-9Zn alloy in NaCl 3 wt%. > Bi and Ag lead to the increase of corrosion rate. > EDS and XRD analyses confirmed the oxide of zinc (ZnO and Zn5(OH){sub 8}Cl{sub 2}H{sub 2}O) as the major corrosion product. - Abstract: The effect of silver (Ag) and bismuth (Bi) on the corrosion resistance of Sn-9Zn alloy in NaCl 3 wt.% solution was investigated using electrochemical techniques. The results showed that the addition of Bi and Ag lead to the increase of corrosion rate and the corrosion potential E{sub corr} is shifted towards less noble values. After immersion, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive of spectroscopy (EDS) analysis of the corroded alloy surface revealed the nature of corrosion products. EDS and XRD analyses confirmed the oxide of zinc (ZnO and Zn{sub 5}(OH){sub 8}Cl{sub 2}H{sub 2}O) as the major corrosion product formed on the outer surface of in the tested three solder alloys.

  5. Microstructure and Mechanical Properties of TIG Weld Joint of ZM5 Magnesium Alloy

    Directory of Open Access Journals (Sweden)

    QIN Ren-yao

    2016-06-01

    Full Text Available The ZM5 magnesium alloy plates were welded by TIG welding method. The microstructural characteristics and mechanical properties of ZM5 magnesium alloy joint were studied by optical microscopy, microhardness and tensile testers. The results show that the TIG weld joint of ZM5 magnesium alloy is composed of heat affected zone, partially melted zone and weld metal. The heat affected zone is consisted of primary α-Mg phase and eutectic phase that is composed of eutectic α-Mg and eutectic β-Mg17Al12 phase and mainly precipitated at grain boundaries. In the partially melted zone, the eutectic phase is not only increasingly precipitated at grain boundaries, but also dispersed in grains, and the growth of the β-Mg17Al12 phase is obviously observed. The microstructure in the weld is the typical dendritic morphology. The dendrites are considered as primary α-Mg phase, and the interdendritic regions are α+β eutectic phase. The difference in the microstructure of the heat affected zone, partially melted zone and weld results in their various microhardness values, and leads to the smaller tensile strength and ductility in the ZM5 alloy weld joint than parent metal.

  6. Magnetic properties of the binary Nickel/Bismuth alloy

    Energy Technology Data Exchange (ETDEWEB)

    Keskin, Mustafa; Şarlı, Numan, E-mail: numansarli82@gmail.com

    2017-09-01

    Highlights: • We model and investigate the magnetic properties of the Ni/Bi alloy within the EFT. • Magnetizations of the Ni/Bi alloy are observed as Bi1 > Bi2 > Ni/Bi > Ni at T < Tc. • Magnetization of the Bi1 is dominant and Ni is at least dominant T < Tc. • Total magnetization of the Ni/Bi alloy is close to those of Ni at T < Tc. • Hysteresis curves are overlap at T < 0.1 and they behave separately at T > 0.1. - Abstract: Magnetic properties of the binary Nickel/Bismuth alloy (Ni/Bi) are investigated within the effective field theory. The Ni/Bi alloy has been modeled that the rhombohedral Bi lattice is surrounded by the hexagonal Ni lattice. According to lattice locations, Bi atoms have two different magnetic properties. Bi1 atoms are in the center of the hexagonal Ni atoms (Ni/Bi1 single layer) and Bi2 atoms are between two Ni/Bi1 bilayers. The Ni, Bi1, Bi2 and Ni/Bi undergo a second-order phase transition from the ferromagnetic phase to paramagnetic phase at Tc = 1.14. The magnetizations of the Ni/Bi alloy are observed as Bi1 > Bi2 > Ni/Bi > Ni at T < Tc; hence the magnetization of the Bi1 is dominant and Ni is at least dominant. However, the total magnetization of the Ni/Bi alloy is close to magnetization of the Ni at T < Tc. The corcivities of the Ni, Bi1, Bi2 and Ni/Bi alloy are the same with each others, but the remanence magnetizations are different. Our theoretical results of M(T) and M(H) of the Ni/Bi alloy are in quantitatively good agreement with the some experimental results of binary Nickel/Bismuth systems.

  7. Influence of alloy microstructure on the microshear bond strength of basic alloys to a resin luting cement.

    Science.gov (United States)

    Bauer, José; Costa, José Ferreira; Carvalho, Ceci Nunes; Souza, Douglas Nesadal de; Loguercio, Alessandro Dourado; Grande, Rosa Helena Miranda

    2012-01-01

    The aim of this study was to evaluate the influence of microstructure and composition of basic alloys on their microshear bond strength (µSBS) to resin luting cement. The alloys used were: Supreme Cast-V (SC), Tilite Star (TS), Wiron 99 (W9), VeraBond II (VBII), VeraBond (VB), Remanium (RM) and IPS d.SIGN 30 (IPS). Five wax patterns (13 mm in diameter and 4mm height) were invested, and cast in a centrifugal casting machine for each basic alloy. The specimens were embedded in resin, polished with a SiC paper and sandblasted. After cleaning the metal surfaces, six tygon tubes (0.5 mm height and 0.75 mm in diameter) were placed on each alloy surface, the resin cement (Panavia F) was inserted, and the excess was removed before light-curing. After storage (24 h/37°C), the specimens were subjected to µSBS testing (0.5 mm/min). The data were subjected to a one-way repeated measures analysis of variance and Turkey's test (α=0.05). After polishing, their microstructures were revealed with specific conditioners. The highest µSBS (mean/standard deviation in MPa) were observed in the alloys with dendritic structure, eutectic formation or precipitation: VB (30.6/1.7), TS (29.8/0.9), SC (30.6/1.7), with the exception of IPS (31.1/0.9) which showed high µSBS but no eutectic formation. The W9 (28.1/1.5), VBII (25.9/2.0) and RM (25.9/0.9) showed the lowest µSBS and no eutectic formation. It seems that alloys with eutectic formation provide the highest µSBS values when bonded to a light-cured resin luting cement.

  8. Solidification microstructures of aluminium-uranium alloys

    International Nuclear Information System (INIS)

    Ambrozio Filho, F.; Vieira, R.R.

    1976-01-01

    The solidification of microstrutures of aluminium-uranium alloys in the range of 4 to 20% uranium is investigated. The solidification was obtained both in ingot molds and under controlled directional solidification. The conditions for the presence of primary crystals and eutectic are discussed and an analysis of the influence of variables (growth rate and thermal gradient in the liquid) on the alloy structure is made. The effect of cooling rate on the alloy structures has been determined. It is found that the resulting structure can be derived from the kinectics concept, as required by the coupled-zone theory. Suggestions on the qualitative intervals of composition and temperatures with eutectic growth are presented [pt

  9. Eutectic crystallization behavior of new Zr48Cu36Al8Ag8 alloy with high glass-forming ability

    International Nuclear Information System (INIS)

    Zhang, Q S; Zhang, W; Xie, G Q; Inoue, A

    2009-01-01

    A water quenching method is used to produce as-cast Zr 48 Cu 36 Al 8 Ag 8 rods with diameters from 20 mm to 25 mm. The microstructures of the as-cast samples were investigated by X-ray diffraction, optical microscopy and scanning electron microscopy. Furthermore, the crystallization behavior of the Zr 48 Cu 36 Al 8 Ag 8 glassy alloy was examined by XRD and transmission electron microscopy. Based on the results obtained one can assume that the simultaneous precipitation of the Zr 2 Cu+AlCu 2 Zr eutectic phases is the possible reason for the high stabilization of the quaternary Zr 48 Cu 36 Al 8 Ag 8 supercooled liquid.

  10. Oxygen partial pressure: a key to alloying and discovery in metal oxide--metal eutectic systems

    International Nuclear Information System (INIS)

    Holder, J.D.; Clark, G.W.; Oliver, B.F.

    1978-01-01

    Control of oxygen partial pressure is essential in the directional solidification of oxide--metal eutectic composites by techniques involving gas-solid and gas-liquid interactions. The existence of end components in the eutectic composite is Po 2 sensitive as are melt stoichiometry, solid phase compositions, and vapor losses due to oxidation-volatilization. Simple criteria are postulated which can aid the experimentalist in selecting the proper gas mixture for oxide--metal eutectic composite growth. The Cr 2 O 3 --Mo--Cr systems was used to verify certain aspects of the proposed criteria

  11. Microstructure and electrochemical corrosion behavior of a Pb-1 wt%Sn alloy for lead-acid battery components

    Energy Technology Data Exchange (ETDEWEB)

    Peixoto, Leandro C.; Osorio, Wislei R.; Garcia, Amauri [Department of Materials Engineering, University of Campinas - UNICAMP, PO Box 612, 13083-970, Campinas - SP (Brazil)

    2009-07-15

    The aim of this study was to evaluate the effect of solidification cooling rates on the as-cast microstructural morphologies of a Pb-1 wt%Sn alloy, and to correlate the resulting microstructure with the corresponding electrochemical corrosion resistance in a 0.5 M H{sub 2}SO{sub 4} solution at 25 C. Cylindrical low-carbon steel and insulating molds were employed permitting the two extremes of a significant range of solidification cooling rates to be experimentally examined. Electrochemical impedance spectroscopy (EIS) diagrams, potentiodynamic polarization curves and an equivalent circuit analysis were used to evaluate the electrochemical corrosion response of Pb-1 wt%Sn alloy samples. It was found that lower cooling rates are associated with coarse cellular arrays which result in better corrosion resistance than fine cells which are related to high cooling rates. The experimental results have shown that that the pre-programming of microstructure cell size of Pb-Sn alloys can be used as an alternative way to produce as-cast components of lead-acid batteries with higher corrosion resistance. (author)

  12. The influence of Ta on the solidification microstructure and segregation behavior of γ(Ni)/γ′(Ni3Al)–δ(Ni3Nb) eutectic Ni-base superalloys

    International Nuclear Information System (INIS)

    Xie, M.; Helmink, R.; Tin, S.

    2013-01-01

    Highlights: ► Ta and Nb have a nominally identical influence on equilibrium δ volume fraction. ► Ta and Nb impact the sequence and segregation differently during solidification. ► Microstructure varies with both overall Ta + Nb level and Ta/Nb ratio. ► Pandat (PanNi7) is unable to predict trends quantitatively in this system. -- Abstract: Polycrystalline γ/γ′–δ eutectic Ni-base superalloys based on the Ni–Al–Nb alloy system were recently demonstrated to possess excellent high temperature strength and creep resistance. Investigations aimed to establish the fundamental relationships between alloy chemistry, solidification behavior and cast microstructure in these novel Ni–Al–Nb γ/γ′–δ alloy systems are currently underway. This particular study is focused on understanding the influence of Ta additions on the solidification sequence, phase volume fraction, distribution coefficient and solid state partitioning parameter of this eutectic alloy system by systematically investigating a series of experimental alloys with nominally constant overall levels of Ta + Nb content but varying Ta/Nb ratios. Although many of the tendencies observed in these multi-component γ/γ′–δ eutectic alloys are in agreement with trends observed in lower order model alloy systems, Ta additions were found to significantly modify solidification characteristics of the alloys. The experimental observations were also used to critically assess the predictive capability of thermodynamic database calculations. Despite the qualitative agreement observed between the experimental results and predictions for relatively simple quaternary and quinary model alloys, comparison of the results for higher order, multi-component γ/γ′–δ eutectic alloys reveals notable differences

  13. Effect of bismuth and strontium interaction on the microstructure development, mechanical properties and fractography of a secondary Al–Si–Cu–Fe–Zn alloy

    International Nuclear Information System (INIS)

    Farahany, Saeed; Idris, Mohd Hasbullah; Ourdjini, Ali

    2015-01-01

    The effect of various additions of bismuth and strontium on the microstructure characteristics, impact and tensile properties, as well as fracture behaviour of a secondary Al–Si–Cu–Fe–Zn under as-cast condition are systematically investigated in this study. The as-cast samples were examined using optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Microstructural analyses showed the occurrence of interaction between Bi and Sr, which, significantly, led to the change of eutectic Si morphology from fibrous to flake morphology, with an increase of mean length, area, and shape factor, an alteration of crystallographic orientation, and an increase in twin density. The mechanical properties were investigated by hardness, impact, and tensile tests with various concentrations of Bi and Sr. It was found that the highest mechanical properties obtained for Sr/Bi were for a ratio of more than 0.44, while deterioration occurred at a ratio of less than 0.32. The hardness, impact toughness, ultimate tensile strength (UTS), elongation to fracture (El), and quality index (Q) of alloys decreased by 7%, 62%, 19%, 57% and 48% respectively when the Sr/Bi ratio diminished from 0.44 to 0.32. The fracture behaviour of impact samples with an Sr/Bi ratio of more than 0.44 showed clear ductile fracture, while the specimens with an Sr/Bi ratio of less than 0.32 presented brittle fracture that corresponds to impact toughness values. Furthermore, the fracture surfaces of tensile samples revealed that the dimple ductile fracture transformed to cleavage brittle mode with drop of the Sr/Bi ratio to less than 0.32 due to an increase in the length, area, and shape factor of eutectic Si. Additionally, the interaction mechanism between Bi and Sr are also discussed in this study

  14. Effect of bismuth and strontium interaction on the microstructure development, mechanical properties and fractography of a secondary Al–Si–Cu–Fe–Zn alloy

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-01-05

    The effect of various additions of bismuth and strontium on the microstructure characteristics, impact and tensile properties, as well as fracture behaviour of a secondary Al–Si–Cu–Fe–Zn under as-cast condition are systematically investigated in this study. The as-cast samples were examined using optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Microstructural analyses showed the occurrence of interaction between Bi and Sr, which, significantly, led to the change of eutectic Si morphology from fibrous to flake morphology, with an increase of mean length, area, and shape factor, an alteration of crystallographic orientation, and an increase in twin density. The mechanical properties were investigated by hardness, impact, and tensile tests with various concentrations of Bi and Sr. It was found that the highest mechanical properties obtained for Sr/Bi were for a ratio of more than 0.44, while deterioration occurred at a ratio of less than 0.32. The hardness, impact toughness, ultimate tensile strength (UTS), elongation to fracture (El), and quality index (Q) of alloys decreased by 7%, 62%, 19%, 57% and 48% respectively when the Sr/Bi ratio diminished from 0.44 to 0.32. The fracture behaviour of impact samples with an Sr/Bi ratio of more than 0.44 showed clear ductile fracture, while the specimens with an Sr/Bi ratio of less than 0.32 presented brittle fracture that corresponds to impact toughness values. Furthermore, the fracture surfaces of tensile samples revealed that the dimple ductile fracture transformed to cleavage brittle mode with drop of the Sr/Bi ratio to less than 0.32 due to an increase in the length, area, and shape factor of eutectic Si. Additionally, the interaction mechanism between Bi and Sr are also discussed in this study.

  15. Ab Initio Molecular Dynamics Studies of Pb m Sb n ( m + n ≤ 9) Alloy Clusters

    Science.gov (United States)

    Song, Bingyi; Xu, Baoqiang; Yang, Bin; Jiang, Wenlong; Chen, Xiumin; Xu, Na; Liu, Dachun; Dai, Yongnian

    2017-10-01

    Structure, stability, and dynamics of Pb m Sb n ( m + n ≤ 9) clusters were investigated using ab initio molecular dynamics. Size dependence of binding energies, the second-order energy difference of clusters, dissociation energy, HOMO-LUMO gaps, Mayer bond order, and the diffusion coefficient of Pb m Sb n clusters were discussed. Results suggest that Pb3Sb2, Pb4Sb2, and Pb5Sb4 ( n = 2 or 4) clusters have higher stability than other clusters, which is consistent with previous findings. In case of Pb-Sb alloy, the dynamics results show that Pb4Sb2 (Pb-22.71 wt pct Sb) can exist in gas phase at 1073 K (800 °C), which reasonably explains the azeotropic phenomenon, and the calculated values are in agreement with the experimental results (Pb-22 wt pct Sb).

  16. Apparent vanishing of ferroelectricity in nanostructured BiScO3PbTiO3

    OpenAIRE

    Amorín , H; Jiménez , R; Ricote , J; Hungría , T; Castro , A; Algueró , M

    2010-01-01

    Abstract Nanostructured ceramics of high-temperature piezoelectric 0.375BiScO 3 -0.625PbTiO 3 were prepared by spark plasma sintering of nanocrystalline powders obtained by mechanosynthesis. The macroscopic electrical properties were characterized on dense ceramics with decreasing average grain size down to 28 nm. Results indicate that the electric field is screened by the electrically insulating grain boundaries at the nanoscale, which needs to be considered when discussing size effects i...

  17. The 208Pb(7Li,6He)209Bi reaction at 52 MeV

    International Nuclear Information System (INIS)

    Zeller, A.F.; Weisser, D.C.; Ophel, T.R.; Hebbard, D.F.

    1979-11-01

    Single proton transfers to low lying levels in 209 Bi from the 208 Pb(7Li, 6 He) reaction at 52 MeV have been measured and spectroscopic factors derived from an EFR-DWBA analysis. Relative spectroscopic factors are in good agreement with light ion results and previous heavy ion work. Absolute spectroscopic factors were generally too large and the peaks of the angular distributions were out of phase with the DWBA calculations by 1 0 - 4 0

  18. The microstructure and composition of equilibrium phases formed in hypoeutectic Te-In alloy during solidification

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Baoguang [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Hu, Jinwu [Center of Failure Analysis, Central Iron and Steel Research Institute, Beijing 100081 (China); Wang, Chongyun; Yang, Wenhui [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Tian, Wenhuai, E-mail: wenhuaitian@ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China)

    2017-03-15

    As a key tellurium atoms evaporation source for ultraviolet detection photocathode, the hypoeutectic Te{sub 75}In{sub 25} alloy was prepared by employing a slow solidification speed of about 10{sup −2} K/s. The microstructure and chemical composition of the equilibrium phases formed in the as-prepared alloy were studied in this research work. The experimental results show that the as-prepared Te-In alloy was constituted by primary In{sub 2}Te{sub 5} phase and eutectic In{sub 2}Te{sub 5}/Te phases. The eutectic In{sub 2}Te{sub 5}/Te phases are distributed in the grain boundaries of primary In{sub 2}Te{sub 5} phase. With the slow solidification speed, a pure eutectic Te phase without any excessive indium solute was obtained, where Te content of eutectic Te phase is 100 mass%. Moreover, it can be considered that the stress between the In{sub 2}Te{sub 5} and Te phases plays an important role in reducing the tellurium vapor pressure in Te{sub 75}In{sub 25} alloy. - Highlights: • The microstructure of Te-In alloy as an evaporation source was analyzed. • A pure eutectic Te phase was obtained by using a slow solidification speed method. • The relation between vapor pressure and inner-stress in the alloy was discussed.

  19. Simulating the Effect of Space Vehicle Environments on Directional Solidification of a Binary Alloy

    Science.gov (United States)

    Westra, D. G.; Heinrich, J. C.; Poirier, D. R.

    2003-01-01

    Space microgravity missions are designed to provide a microgravity environment for scientific experiments, but these missions cannot provide a perfect environment, due to vibrations caused by crew activity, on-board experiments, support systems (pumps, fans, etc.), periodic orbital maneuvers, and water dumps. Therefore, it is necessary to predict the impact of these vibrations on space experiments, prior to performing them. Simulations were conducted to study the effect of the vibrations on the directional solidification of a dendritic alloy. Finite element ca!cu!attie?ls were dme with a simd2titcr based on a continuum model of dendritic solidification, using the Fractional Step Method (FSM). The FSM splits the solution of the momentum equation into two steps: the viscous intermediate step, which does not enforce continuity; and the inviscid projection step, which calculates the pressure and enforces continuity. The FSM provides significant computational benefits for predicting flows in a directionally solidified alloy, compared to other methods presently employed, because of the efficiency gains in the uncoupled solution of velocity and pressure. finite differences, arises when the interdendritic liquid reaches the eutectic temperature and concentration. When a node reaches eutectic temperature, it is assumed that the solidification of the eutectic liquid continues at constant temperature until all the eutectic is solidified. With this approach, solidification is not achieved continuously across an element; rather, the element is not considered solidified until the eutectic isotherm overtakes the top nodes. For microgravity simulations, where the convection is driven by shrinkage, it introduces large variations in the fluid velocity. When the eutectic isotherm reaches a node, all the eutectic must be solidified in a short period, causing an abrupt increase in velocity. To overcome this difficulty, we employed a scheme to numerically predict a more accurate value

  20. Preparation of (Bi, Pb)-2223/Ag tapes by high temperature sintering and post-annealing process

    DEFF Research Database (Denmark)

    Hua, L.; Grivel, Jean-Claude; Andersen, L.G.

    2002-01-01

    A novel heat treatment process was developed to fabricate (Bi, Pb)-2223/Ag tapes with high critical current density (J(c)). The process can be divided into two parts: reformation and post-annealing. Tapes were first heated to the maximum temperature (830-860 degreesC) followed by slow cooling...... (reformation). Then, tape, were annealed between 760 and 820 degreesC (post-annealing). Reformation is expected to produce a large amount of liquid phase which may heat microcracks, decrease porosity, and improve grain growth. However, since the sintering temperature is beyond the Bi-2223 single-phase region......-energy synchrotron XRD and SEM/EDX. Some process parameters e.g. sintering temperature. cooling rate. and post-annealing time were optimised. (C) 2002 Elsevier Science B.V. All rights reserved....

  1. Design and qualification of an on-line permeator for the recovery of tritium from lead-lithium eutectic breeding alloy

    International Nuclear Information System (INIS)

    Veredas, G.; Fradera, J.; Fernandez, I.; Batet, L.; Penalva, I.; Mesquida, L.; Abella, J.; Sempere, J.; Martinez, I.; Herrazti, B.; Sedano, L.

    2011-01-01

    The fast and efficient recovery of bred tritium represents a major milestone of tritium breeding technologies R and D and is key for the demonstration of fusion reactor fuel self-sufficiency. For lead-lithium eutectic, diverse technologies are currently being investigated and qualified. Permeator Against Vacuum (PAV) solution represents a firm candidate because: (i) runs as a single-step process for tritium on-line recovery, (ii) works passively allowing to be thermally governed, (iii) can be easily in-pipe integrated in Pb15.7Li loop systems and (iv) can be conceived with high compactness. An optimal design of a PAV requires a detailed hydraulic design optimization for established operational ranges. An optimal PAV design is proposed and qualified by numerical simulation.

  2. Microstructure of laser floating zone (LFZ) textured (Bi,Pb)-Sr-Ca-Cu-O superconductor composites

    International Nuclear Information System (INIS)

    Fuente, G.F. de la; Ruiz, M.T.; Sotelo, A.; Larrea, A.; Navarro, R.

    1993-01-01

    Directionally solidified high temperature superconducting (Bi,Pb)-Sr-Ca-Cu-O pure ceramics and composites were obtained using a laser floating zone (LFZ) apparatus. The presence of secondary non-superconducting and metallic phases as well as their solidification habit have been analysed. The influence of the LFZ growth conditions and the precursor composition on the microstructure of the final products was studied using optical and electron microscopies. (orig.)

  3. Shielded high-T{sub c} (Bi, Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} (Bi-2223) superconducting tapes

    Energy Technology Data Exchange (ETDEWEB)

    Lelovic, M.; Eror, N.G. [Department of Materials Science, University of Pittsburgh, Pittsburgh, PA (United States); Balachandran, U.; Prorok, B. [Energy Technology Division, Argonne National Laboratory, Argonne, IL (United States); Selvamanickam, V.; Haldar, P. [Intermagnetics General Corporations, Latham, NY (United States); Talvacchio, J.; Young, R. [Science and Technology Center, Northrop Grumman, Pittsburgh, PA (United States)

    1998-11-01

    A new composite tape was fabricated in which the primary function of the central Ag-sheathed (Bi, Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} (Bi-2223) filaments was to conduct transport current. A YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (Y-123) thin film was deposited on the top of the Ag-sheathed Bi-2223 tape to shield the applied magnetic field and to protect the central Bi-2223 filaments. The critical current densities of the Y-123-coated, Ag-sheathed Bi-2223 tapes were better than those of an uncoated tape. However, the Y-123 thin film exhibited T{sub c} approx.= 72 K and a broad transition region that shifted the effect to lower temperatures. Furthermore, pole figure measurements showed widely spread a,b planes along the rolling direction, indicating high-angle grain boundaries that diminished the magnitude of the effect. Microstructural observations showed platelike grains of Y-123 with fine growth ledges in the thin film that was heat treated, in contrast with the microstructure of an as-coated thin film that showed large twinned grains. From the processing point of view, the results showed that heat treating Y-123 thin film according to the Bi-2223 tape schedule was compatible with and beneficial for Y-123. These preliminary results may provide a basis for further improvements in processing of long-length Bi-2223 tapes for high-field applications. (author)

  4. Coordination chemistry of the 212Pb/212Bi nuclear transformation: Alpha-emitting radiopharmaceuticals

    International Nuclear Information System (INIS)

    Parks, N.J.; Harris, W.R.; Keen, C.L.; Cooper, S.R.

    1992-07-01

    Subdivisions of this project are: (a) the synthesis of prototypical thiolate and dithiocarbamate based hexacoordinate complexes, (b) radiochemical engineering for generation of no-carrier-added lead and bismuth radioelements, (c) the first isolation of bismuth-binding proteins from in vivo studies with cyclotron produced 205/206 Bi tracer, and (d) initial development of transport mechanisms for the intracellular radiobiological study of alpha emitting bismuth, and (e) the initiation of chemical equilibrium studies and biochemical pathways with cyclotron-produced, no-carrier-added, 203 Pb (T 1/2 = 51 hr)

  5. Rapid solidification growth mode transitions in Al-Si alloys by dynamic transmission electron microscopy

    International Nuclear Information System (INIS)

    Roehling, John D.; Coughlin, Daniel R.; Gibbs, John W.; Baldwin, J. Kevin; Mertens, James C.E.; Campbell, Geoffrey H.; Clarke, Amy J.; McKeown, Joseph T.

    2017-01-01

    In situ dynamic transmission electron microscope (DTEM) imaging of Al-Si thin-film alloys was performed to investigate rapid solidification behavior. Solidification of alloys with compositions from 1 to 15 atomic percent Si was imaged during pulsed laser melting and subsequent solidification. Solely α-Al solidification was observed in Al-1Si and Al-3Si alloys, and solely kinetically modified eutectic growth was observed in Al-6Si and Al-9Si alloys. A transition in the solidification mode in eutectic and hypereutectic alloys (Al-12Si and Al-15Si) from nucleated α-Al dendrites at lower solidification velocities to planar eutectic growth at higher solidification velocities was observed, departing from trends previously seen in laser-track melting experiments. Comparisons of the growth modes and corresponding velocities are compared with previous solidification models, and implications regarding the models are discussed.

  6. Separation of 210Pb, 210Bi and 210Po by ion exchange and their Iiquid scintillation standardization

    International Nuclear Information System (INIS)

    Rodriguez, L.; Jimenez, A.; Grau, A.

    1996-01-01

    We applied the CIEMAT/NIST method and alpha/beta discrimination to ''210Pb samples in equilibrium with its daughters, by preparing homogeneous and gel samples. The stability of samples was tested in different available cocktails, HiSafe''TM II, HiSafe''TM III, Ultima-Gold''TM, Ultima-Gold''TM XR, Ultima-Gold''TM AB, Insta-Gel''R and e Insta-Gel''R lI. Also we analyzed the disequilibrium of the radioactive chain 210Pb+210Bi+210Po, achieving an excellent agreement between the results of the spectrum unfolding method and the experimental values. (Author) 13 refs

  7. Tuning the giant Rashba effect on a BiAg2 surface alloy: Two different approaches

    International Nuclear Information System (INIS)

    Frantzeskakis, E.; Crepaldi, A.; Pons, S.; Kern, K.; Grioni, M.

    2010-01-01

    We discuss two different approaches for tuning the giant spin-orbit splitting of a BiAg 2 surface alloy. The first approach consists of electron doping by alkaline metal deposition in order to shift the energy position of the spin-split surface states, while the second is based on the novel Si(1 1 1)-Ag-BiAg 2 trilayer system. In both cases the spin-polarized structure near the Fermi level can be controlled by an external parameter, while the second approach permits coupling the concept of giant spin-splitting with a semiconducting substrate.

  8. Review of possible experiments in the eutectic growth and thermodiffusion fields

    International Nuclear Information System (INIS)

    Malmejac, Yves.

    1976-01-01

    The results now available from the SKYLAB and ASTP programmes give a clearer indication of the lines of the research to pursue in the years to come. The criteria necessary for the choice of experiments are analysed in the fields of eutectic solidification and diffusion along a temperature gradient in liquid alloys [fr

  9. Pb solubility of the high-temperature superconducting phase Bi2Sr2Ca2Cu3O10+d

    International Nuclear Information System (INIS)

    Kaesche, S.; Majewski, P.; Aldinger, F.

    1994-01-01

    For the nominal composition of Bi 2.27x Pb x Sr 2 Ca 2 Cu 3 O 10+d the lead content was varied from x=0.05 to 0.45. The compositions were examined between 830 degrees C and 890 degrees C which is supposed to be the temperature range over which the so-called 2223 phase (Bi 2 Sr 2 Ca 2 Cu 3 O 10+d ) is stable. Only compositions between x=0.18 to 0.36 could be synthesized in a single phase state. For x>0.36 a lead containing phase with a stoichiometry of Pb 4 (Sr,Ca) 5 CuO d is formed, for x 2 Sr 2 CaCu 2 O 8+d and cuprates are the equilibrium phases. The temperature range for the 2223 phase was found to be 830 degrees C to 890 degrees C but the 2223 phase has extremely varying cation ratios over this temperature range. Former single phase 2223 samples turn to multi phase samples when annealed at slightly higher or lower temperatures. A decrease in the Pb solubility with increasing temperature was found for the 2223 phase

  10. Aluminum alloy and associated anode and battery

    International Nuclear Information System (INIS)

    Tarcy, G.P.

    1990-01-01

    This patent describes an aluminum alloy. It comprises: eutectic amounts of at least two alloying elements selected from the group consisting of bismuth, cadmium, scandium, gallium, indium, lead, mercury, thallium, tin, and zinc with the balance being aluminum and the alloying elements being about 0.01 to 3.0 percent by weight of the alloy

  11. Mineralogical data on angelaite, Cu2AgPbBiS4, from the Los Manantiales District, Chubut, Argentina

    DEFF Research Database (Denmark)

    Topa, D.; Paar, W.H.; Putz, H.

    2010-01-01

    Angelaite, ideally Cu2AgPbBiS4, occurs as a hypogene mineral in polymetallic ores at the Ángela groups of veins in the mining district of Los Manantiales, in the province of Chubut, Argentina. The new mineral species is predominantly associated with pyrite, sphalerite, chalcopyrite, hematite...

  12. Evolution of thermoelectric performance for (Bi,Sb){sub 2}Te{sub 3} alloys from cutting waste powders to bulks with high figure of merit

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Xi' an, E-mail: groupfxa@163.com [The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081 (China); School of Materials and Metallurgy, Wuhan University of Science and Technology, 947 Heping Road, Qingshan District, Wuhan 430081 (China); Cai, Xin zhi, E-mail: xzcwust@163.com [The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081 (China); School of Materials and Metallurgy, Wuhan University of Science and Technology, 947 Heping Road, Qingshan District, Wuhan 430081 (China); Han, Xue wu, E-mail: hanxuewu1990@163.com [The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081 (China); School of Materials and Metallurgy, Wuhan University of Science and Technology, 947 Heping Road, Qingshan District, Wuhan 430081 (China); Zhang, Cheng cheng, E-mail: zcc516990418@live.com [The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081 (China); School of Materials and Metallurgy, Wuhan University of Science and Technology, 947 Heping Road, Qingshan District, Wuhan 430081 (China); and others

    2016-01-15

    Bi{sub 2}Te{sub 3} based cutting waste powders from cutting wafers were firstly selected as raw materials to prepare p-type Bi{sub 2}Te{sub 3} based thermoelectric (TE) materials. Through washing, reducing, composition correction, smelting and resistance pressing sintering (RPS) process, p-type (Bi,Sb){sub 2}Te{sub 3} alloy bulks with different nominal stoichiometries were successfully obtained. The evolution of microstructure and TE performance for (Bi,Sb){sub 2}Te{sub 3} alloys were investigated in detail. All evidences confirmed that most of contaminants from line cutting process such as cutting fluid and oxides of Bi, Sb or Te could be removed by washing, reducing and smelting process used in this work. The carrier content and corresponding TE properties could be adjusted effectively by appropriate composition correction treatment. At lastly, a bulk with a nominal stoichiometry of Bi{sub 0.44}Sb{sub 1.56}Te{sub 3} was obtained and its' dimensionless figure of merit (ZT) was about 1.16 at 90 °C. The ZT values of Bi{sub 0.36}Sb{sub 1.64}Te{sub 3} and Bi{sub 0.4}Sb{sub 1.6}Te{sub 3} alloy bulks could also reach 0.98 and 1.08, respectively. Different from the conventional recycling technology such as hydrometallurgy extraction methods, the separation and extraction of beneficial elements such as Bi, Sb and Te did not need to be performed and the Bi{sub 2}Te{sub 3} based bulks with high TE properties could be directly obtained from the cutting waste powders. In addition, the recycling technology introduced here was green and more suitable for practical industrial application. It can improve material utilization and lower raw material costs of manufacturers. - Graphical abstract: Three kinds of typical morphologies for the fractographs: typical lamellar structure, agglomerated submicron-sized granules and dispersed cubic particles from the initial cutting waste powders. - Highlights: • Bi{sub 2}Te{sub 3} based wastes were directly selected as raw materials

  13. Reactor core design optimization of the 200 MWt Pb-Bi cooled fast reactor for hydrogen production

    International Nuclear Information System (INIS)

    Bahrum, Epung Saepul; Su'ud, Zaki; Waris, Abdul; Fitriyani, Dian; Wahjoedi, Bambang Ari

    2008-01-01

    In this study reactor core geometrical optimization of 200 MWt Pb-Bi cooled long life fast reactor for hydrogen production has been conducted. The reactor life time is 20 years and the fuel type is UN-PuN. Geometrical core configurations considered in this study are balance, pancake and tall cylindrical cores. For the hydrogen production unit we adopt steam membrane reforming hydrogen gas production. The optimum operating temperature for the catalytic reaction is 540degC. Fast reactor design optimization calculation was run by using FI-ITB-CHI software package. The design criteria were restricted by the multiplication factor that should be less than 1.002, the average outlet coolant temperature 550degC and the maximum coolant outlet temperature less than 700degC. By taking into account of the hydrogen production as well as corrosion resulting from Pb-Bi, the balance cylindrical geometrical core design with diameter and height of the active core of 157 cm each, the inlet coolant temperature of 350degC and the coolant flow rate of 7000 kg/s were preferred as the best design parameters. (author)

  14. Removal of lead from the industrial and synthetic Cu-Pb-Fe alloy with argon barbotage

    Directory of Open Access Journals (Sweden)

    B. Oleksiak

    2012-01-01

    Full Text Available Results of research on removal of lead from synthetic and industrial Cu-Pb-Fe alloy with argon barbotage are presented. For examinations was taken a synthetic alloy and industrial alloy coming “Glogow II” Copperworks. As basic research equipment was used a pipe resistance furnace enabling heating of samples up to 1 473 K. Examinations were made in 2 test series. The 1 series was performed on the synthetic alloy, while in 2 series was used an industrial alloy. All series were conducted at 1 473 K and with gas fl ow 5,55•10-6, 6,94•10-6, 8,33•10-6, 9,72•10-6 m3•s-1.

  15. Dielectric and magnetic properties of Ba-, La- and Pb-doped Bi0.8Gd0.1M0.1Fe0.9Ti0.1O3 perovskite ceramics

    Directory of Open Access Journals (Sweden)

    Radheshyam Rai

    2014-04-01

    Full Text Available The multiferroic Bi0.8Gd0.1M0.1Fe0.9Ti0.1O3, (where M = Ba (DB, La (DL and Pb (DP has been synthesized by using solid-state reaction technique. Effects of Ba, La and Pb substitution on the structure, electrical and ferroelectric properties of Bi0.8Gd0.1M0.1Fe0.9Ti0.1O3 samples have been studied by performing X-ray diffraction, dielectric and magnetic measurements. The crystal structures of the ceramic samples have a tetragonal phase. The vibrating sample magnetometer (VSM measurement shows a significant change in the magnetic properties of Ba-doped Bi0.8Gd0.1M0.1Fe0.9Ti0.1O3 as compared to La- and Pb-doped ceramics. It is seen that coercive field (HC and remanent magnetization (MR increases with Ba-doped ceramics but decreases for La- and Pb-doped ceramics.

  16. Structural and electronic properties of Pb-doped Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10}: Comparison of LDA and GGA calculations

    Energy Technology Data Exchange (ETDEWEB)

    Camargo-Martínez, J.A., E-mail: jcamargo@unitropico.edu.co [Grupo de Investigación en Ciencias Básicas, Aplicación e Innovación - CIBAIN, Fundación Universitaria Internacional del Trópico Americano– Unitrópico, Yopal, Casanare (Colombia); Martínez-Pieschacón, D.J. [Departamento de Ciencias Básicas, Universidad Santo Tomás, Tunja, Boyaca (Colombia); Baquero, R. [Departamento de Física, CINVESTAV-IPN, Av. IPN 2508, 07360, México (Mexico)

    2017-04-15

    Highlights: • We present for the first time the effects of Pb doping on structural and electronic properties of Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} (Bi2223) using GGA, compared with LDA results. • We found the Pb concentration for which the Bi–O pockets disappear from the Fermi Surface in the Bi2223 compound using GGA and LDA, respectively. - Abstract: We use Density Functional Theory to study the effects on the crystal structure and the electronic band structure of substituting Pb for Bi in Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10}. We further use the Local Density Approximation (LDA) and the Generalized Gradient Approximation (GGA). The Virtual Crystal Approximation (VCA) was used to account for the substitution. We found that GGA reproduces better the lattice parameters although in both cases the internal coordinates were reproduced with some uncertainties. We further looked at the behavior of the so called Bi–O pockets, some electronic states that originate on the Bi–O planes and that appear on the Fermi surface (FS) in contradiction to the experimental evidence. We found that LDA and GGA differ on that subject. With 26% Pb and using LDA, the Bi–O pockets run away from the FS. But when GGA is used, it is needed up to 35% Pb to make the Bi–O pockets disappear from the FS. In the last case, once the Bi–O pockets are removed from the FS, we get a very good agreement with angular resolved photo-emission (ARPES) and nuclear magnetic resonance (NMR) experiments.

  17. Idaho National Laboratory Lead or Lead-Bismuth Eutectic (LBE) Test Facility - R&D Requirements, Design Criteria, Design Concept, and Concept Guidance

    Energy Technology Data Exchange (ETDEWEB)

    Eric P. Loewen; Paul Demkowicz

    2005-05-01

    The Idaho National Laboratory Lead-Bismuth Eutectic Test Facility will advance the state of nuclear technology relative to heavy-metal coolants (primarily Pb and Pb-Bi), thereby allowing the U.S. to maintain the pre-eminent position in overseas markets and a future domestic market. The end results will be a better qualitative understanding and quantitative measure of the thermal physics and chemistry conditions in the molten metal systems for varied flow conditions (single and multiphase), flow regime transitions, heat input methods, pumping requirements for varied conditions and geometries, and corrosion performance. Furthering INL knowledge in these areas is crucial to sustaining a competitive global position. This fundamental heavy-metal research supports the National Energy Policy Development Group’s stated need for energy systems to support electrical generation.1 The project will also assist the Department of Energy in achieving goals outlined in the Nuclear Energy Research Advisory Committee Long Term Nuclear Technology Research and Development Plan,2 the Generation IV Roadmap for Lead Fast Reactor development, and Advanced Fuel Cycle Initiative research and development. This multi-unit Lead-Bismuth Eutectic Test Facility with its flexible and reconfigurable apparatus will maintain and extend the U.S. nuclear knowledge base, while educating young scientists and engineers. The uniqueness of the Lead-Bismuth Eutectic Test Facility is its integrated Pool Unit and Storage Unit. This combination will support large-scale investigation of structural and fuel cladding material compatibility issues with heavy-metal coolants, oxygen chemistry control, and thermal hydraulic physics properties. Its ability to reconfigure flow conditions and piping configurations to more accurately approximate prototypical reactor designs will provide a key resource for Lead Fast Reactor research and development. The other principal elements of the Lead-Bismuth Eutectic Test Facility

  18. Synthesis and Microstructure Properties of (Bi,Pb2Sr2Ca1Cu2Oy Ceramic Superconductor

    Directory of Open Access Journals (Sweden)

    nurmalita .

    2015-11-01

    Full Text Available Properties of (Bi, Pb2Sr2Ca1Cu2Oy ceramic superconductors were prepared by the melt textured growth methods in order to investigate the effects of the slow cooling time on the microstructur.  Phase analyses of the samples by X-ray diffraction (XRD has been carried out to assess the effects of the slow cooling time. From XRD analyses, the addition to the sample of  the slow cooling time degrades formation of the high-Tc Bi-2212 phase. The possible reasons for the observed degradation in the microstructure properties due to the slow cooling time addition were discussed.

  19. Magnetoelectric properties of Pb free Bi2FeTiO6: A theoretical investigation

    Science.gov (United States)

    Patra, Lokanath; Ravindran, P.

    2018-05-01

    The structural, electronic, magnetic and ferroelectric properties of Pb free double perovskite multiferroic Bi2FeTiO6 are investigated using density functional theory within the general gradient approximation (GGA) method. Our structural optimization using total energy calculations for different potential structures show a minimum energy for a non-centrosymmetric rhombohedral structure with R3c space group. Bi2FeTiO6 is found to be an antiferromagnetic insulator with C-type magnetic ordering with bandgap value of 0.3 eV. The calculated magnetic moment of 3.52 μB at Fe site shows the high spin arrangement of 3d electrons which is also confirmed by our orbital projected density of states analysis. We have analyzed the characteristics of bonding present between the constituents of Bi2FeTiO6 with the help of calculated partial density of states and Born effective charges. The ground state of the nearest centrosymmetric structure is found to be a G-type antiferromagnet with half metallicity showing that by the application of external electric field we can not only get a polarized state but also change the magnetic ordering and electronic structure in the present compound indicating strong magnetoelectric coupling. The cation sites the coexistence of Bi 6s lone pair (bring disproportionate charge distribution) and Ti4+ d0 ions which brings covalency produces off-center displacement and favors a non-centrosymmetric ground state and thus ferroelectricity. Our Berry phase calculation gives a polarization of 48 µCcm-2 for Bi2FeTiO6.

  20. Thermoelectric properties of p-type (Bi{sub 1{minus}x}Sb{sub x}){sub 2}Te{sub 3} fabricated by mechanical alloying process

    Energy Technology Data Exchange (ETDEWEB)

    Jung, B Y; Choi, J S; Oh, T S; Hyun, D B

    1997-07-01

    Thermoelectric properties of polycrystalline (Bi{sub 1{minus}x}Sb{sub x}){sub 2}Te{sub 3} (0.75 {le} x {le} 0.85), fabricated by mechanical alloying and hot pressing methods, have been investigated. Formation of (Bi{sub 0.25}Sb{sub 0.75}){sub 2}Te{sub 3} alloy powder was completed by mechanical alloying for 5 hours at ball-to-material ratio of 5:1, and processing time for (Bi{sub 1{minus}sub x}Sb{sub x}){sub 2}Te{sub 3} formation increased with Sb{sub 2}Te{sub 3} content x. When (Bi{sub 0.25}Sb{sub 0.75}){sub 2}Te{sub 3} was hot pressed at temperatures ranging from 300 C to 550 C for 30 minutes, figure-of-merit increased with hot pressing temperature and maximum value of 2.8 x 10{sup {minus}3}/K could be obtained by hot pressing at 550 C. When hot pressed at 550 C, (Bi{sub 0.2}Sb{sub 0.8}){sub 2}Te{sub 3} exhibited figure-of-merit of 2.92 x 10{sup {minus}3}/K, which could be improved to 2.97 x 10{sup {minus}3}/K with addition of 1 wt% Sb as acceptor dopant.

  1. On the position of local levels of defects in proton-irradiated Pb1-xSnxTe alloys

    International Nuclear Information System (INIS)

    Brandt, N.B.; Gas'kov, A.M.; Ladygin, E.A.; Skipetrov, E.P.; Khorosh, A.G.

    1989-01-01

    Effect of fast proton irradiation (T≅300 K, E=200 keV, F≤2x10 14 cm -2 ) on electrophysical properties of thin layers p-Pb 1-x Sn x Te (0.17 ≤x≤ 0.26) is investigated. Saturation of radiation flux dependences of hole density due to occurrence of a resonance level under irradiation, which is near the ceiling of the valence band of alloys, and due to stabilization of the Fermi level with the resonance level is detected. Possibility of coordination of novadays data on the position of the levels of radiation defects in alloys Pb 1-x Sn x Te is discussed

  2. Role of cerium, lanthanum, and strontium additions in an Al-Si-Mg (A356) alloy

    Energy Technology Data Exchange (ETDEWEB)

    Nabawy, Ahmed M.; Samuel, Agnes M.; Samuel, Fawzy H. [Universite du Quebec, Chicoutimi (Canada). Dept. des Sciences Appliquees; Alkahtani, Saleh A.; Abuhasel, Khaled A. [Salman Bin Abdulaziz Univ., Riyadh (Saudi Arabia). Mechanical Engineering Dept.

    2016-05-15

    The effects of individual and combined additions of cerium (Ce), lanthanum (La), and strontium (Sr) on the eutectic modification and solidification characteristics of an Al-Si-Mg (A356) aluminum alloy were investigated using optical microscopy and thermal analysis techniques. Addition of Ce, La, and Sr resulted in different depression levels of the eutectic nucleation temperature and eutectic growth undercooling, generating modified eutectic structures exhibiting different levels of modification. Microstructural results showed that the best modification levels using individual additions were achieved by Sr which produced a fine fibrous eutectic structure, followed by La, which produced a refined lamellar structure, with Ce providing the lowest level of modification. On the other hand, a combined addition of Ce and Sr provided the highest modification level, with the production of a very fine fibrous eutectic silicon structure. In general, the addition of Sr helped to further increase the refinement obtained in the alloys containing La or Ce + La additions. In the latter alloy, the main intermetallic phases observed were La(Al,Si){sub 2} and Al{sub 20}(La,Ce)Ti{sub 2}Si. The improved modification levels were found to be proportional to the depression in the eutectic nucleation temperature and the eutectic growth undercooling. A high cooling rate also improved the modification level by at least one level.

  3. Sulfide phase in the Fe-Ti-S and Fe-C-Ti-S alloys

    International Nuclear Information System (INIS)

    Malinochka, Ya.N.; Balakina, N.A.; Shmelev, Yu.S.

    1976-01-01

    The nature of the sulfide phases in Fe-Ti-S and Fe-C-Ti-S alloys was studied. The carbide and the sulfide phase were identified the aid of X-ray spectral microanalysis. It was established that for a small content of titanium and sulfur in ternary Fe-Ti-S alloys the solidification of the γ-solution on the boundaries of dendritic branches is accompanied, along with the precipitation of a sulfide rich in iron of the (Fe, Ti) S type where a small quantity of titanium is dissolved, by the formation of a titanium-bearing sulfide eutectic γ + TiS. The amount of the sulfide eutectic increases with the contents of titanium and sulfur until a purely eutectic alloy is formed. Both carbides and sulfides may be formed in the solidification of quaternary alloys Fe-C-Ti-S

  4. Wafer-level integration of NiTi shape memory alloy on silicon using Au–Si eutectic bonding

    International Nuclear Information System (INIS)

    Gradin, Henrik; Bushra, Sobia; Braun, Stefan; Stemme, Göran; Van der Wijngaart, Wouter

    2013-01-01

    This paper reports on the wafer level integration of NiTi shape memory alloy (SMA) sheets with silicon substrates through Au–Si eutectic bonding. Different bond parameters, such as Au layer thicknesses and substrate surface treatments were evaluated. The amount of gold in the bond interface is the most important parameter to achieve a high bond yield; the amount can be determined by the barrier layers between the Au and Si or by the amount of Au deposition. Deposition of a gold layer of more than 1 μm thickness before bonding gives the most promising results. Through patterning of the SMA sheet and by limiting bonding to small areas, stresses created by the thermal mismatch between Si and NiTi are reduced. With a gold layer of 1 μm thickness and bond areas between 200 × 200 and 800 × 800 μm 2 a high bond strength and a yield above 90% is demonstrated. (paper)

  5. The investigation of topological phase of Gd1-xYxAuPb (x = 0, 0.25, 0.5, 0.75, 1) alloys under hydrostatic pressure

    Science.gov (United States)

    Saeidi, Parviz; Nourbakhsh, Zahra

    2018-04-01

    Topological phase of Gd1-xYxAuPb (x = 0, 0.25, 0.5, 0.75, 1) alloys have been studied utilizing density function theory by WIEN2k code. The generalized gradient approximation (GGA), generalized gradient approximation plus Hubbard parameter (GGA + U), Modified Becke and Johnson (MBJ) and GGA Engel-vosko in the presence of spin orbit coupling have been used to investigate the topological band structure of Gd1-xYxAuPb alloys at zero pressure. The topological phase and band order of these alloys within GGA and GGA + U approaches under hydrostatic pressure are also investigated. We find that under hydrostatic pressure in some percentages of Gd1-xYxAuPb (x = 0, 0.25, 0.5, 0.75, 1) alloys in both GGA and GGA + U approaches, the trivial topological phase is converted into nontrivial topological phase. In addition, the band inversion strength versus lattice constant of these alloys is studied. Moreover, the schematic plan is represented in order to show the trivial and nontrivial topological phase of Gd1-xYxAuPb (x = 0, 0.25, 0.5, 0.75, 1) alloys in both GGA and GGA + U approaches.

  6. Amperometric detection and electrochemical oxidation of aliphatic amines and ammonia on silver-lead oxide thin-film electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Jisheng [Iowa State Univ., Ames, IA (United States)

    1996-01-08

    This thesis comprises three parts: Electrocatalysis of anodic oxygen-transfer reactions: aliphatic amines at mixed Ag-Pb oxide thin-film electrodes; oxidation of ammonia at anodized Ag-Pb eutectic alloy electrodes; and temperature effects on oxidation of ethylamine, alanine, and aquated ammonia.

  7. Competition from the ν/sub e/ 208Pb → 208Bi e- reaction in a search for ν/sub μ/-bar → ν/sub e/-bar oscillation

    International Nuclear Information System (INIS)

    Toevs, J.W.; Kruse, H.W.

    1981-01-01

    Inverse beta-decay reactions produced by electron neutrinos may compete with muon neutrino reactions in experiments utilizing the neutrino flux from a beam stop. The cross section and angular distribution for one such reaction, ν/sub e/ 208 Pb → 208 Bi e - , have been calculated with the aid of the results of an investigation of 208 Pb (p,n) 208 Bi at low momentum transfer. The implications of this reaction on an experiment to study neutrino oscillation are discussed. 2 figures

  8. Band structure of metallic pyrochlore ruthenates Bi2Ru2O7 and Pb2Ru2O/sub 6.5/

    International Nuclear Information System (INIS)

    Hsu, W.Y.; Kasowski, R.V.; Miller, T.; Chiang, T.

    1988-01-01

    The band structure of Bi 2 Ru 2 O 7 and Pb 2 Ru 2 O/sub 6.5/ has been computed self-consistently from first principles for the first time by the pseudofunction method. We discover that the 6s bands of Bi and Pb are very deep and unlikely to contribute to the metallic behavior as previously believed. The unoccupied 6p bands, however, are only several eV above the Fermi energy and are mixed with the Ru 4d band at the Fermi surface via the framework O atoms, leading to band conduction and delocalized magnetic moments. The predicted location of the 6s bands and the location and width of the O 2p band are confirmed by synchrotron radiation and ultraviolet electron spectroscopy of single crystals

  9. A new indicator mineral methodology based on a generic Bi-Pb-Te-S mineral inclusion signature in detrital gold from porphyry and low/intermediate sulfidation epithermal environments in Yukon Territory, Canada

    Science.gov (United States)

    Chapman, R. J.; Allan, M. M.; Mortensen, J. K.; Wrighton, T. M.; Grimshaw, M. R.

    2017-12-01

    Porphyry-epithermal and orogenic gold are two of the most important styles of gold-bearing mineralization within orogenic belts. Populations of detrital gold resulting from bulk erosion of such regions may exhibit a compositional continuum wherein Ag, Cu, and Hg in the gold alloy may vary across the full range exhibited by natural gold. This paper describes a new methodology whereby orogenic and porphyry-epithermal gold may be distinguished according to the mineralogy of microscopic inclusions observed within detrital gold particles. A total of 1459 gold grains from hypogene, eluvial, and placer environments around calc-alkaline porphyry deposits in Yukon (Nucleus-Revenue, Casino, Sonora Gulch, and Cyprus-Klaza) have been characterized in terms of their alloy compositions (Au, Ag, Cu, and Hg) and their inclusion mineralogy. Despite differences in the evolution of the different magmatic hydrothermal systems, the gold exhibits a clear Bi-Pb-Te-S mineralogy in the inclusion suite, a signature which is either extremely weak or (most commonly) absent in both Yukon orogenic gold and gold from orogenic settings worldwide. Generic systematic compositional changes in ore mineralogy previously identified across the porphyry-epithermal transition have been identified in the corresponding inclusion suites observed in samples from Yukon. However, the Bi-Te association repeatedly observed in gold from the porphyry mineralization persists into the epithermal environment. Ranges of P-T-X conditions are replicated in the geological environments which define generic styles of mineralization. These parameters influence both gold alloy composition and ore mineralogy, of which inclusion suites are a manifestation. Consequently, we propose that this methodology approach can underpin a widely applicable indicator methodology based on detrital gold.

  10. Thermoelectric properties of n-type Bi{sub 2}(Te{sub 1{minus}x}Se{sub x}){sub 3} fabricated by mechanical alloying and hot pressing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H J; Choi, J S; Oh, T S; Hyun, D B

    1997-07-01

    Thermoelectric properties of polycrystalline Bi{sub 2}(Te{sub 1{minus}x}Se{sub x}){sub 3} (0.05 {le} x {le} 0.25), fabricated by mechanical alloying and hot pressing, have been investigated. Formation of n-type Bi{sub 2}(Te{sub 0.9}Se{sub 0.1}){sub 3} alloy powders was completed by mechanical alloying for 3 hours at ball-to-material ratio of 5:1, and processing time for Bi{sub 2}(Te{sub 1{minus}x}Se{sub x}){sub 3} formation increased with Bi{sub 2}Se{sub 3} content x. Figure-of-merit of Bi{sub 2}(Te{sub 0.9}Se{sub 0.1}) was markedly increased by hot pressing at temperatures above 450 C, and maximum value of 1.9 x 10{sup {minus}3}/K was obtained by hot pressing at 550 C. With addition of 0.015 wt% Bi as acceptor dopant, figure-of-merit of Bi{sub 2}(Te{sub 0.9}Se{sub 0.1}){sub 3} was hot pressed at 550 C, could be improved to 2.1 x 10{sup {minus}3}/K. When Bi{sub 2}(Te{sub 1{minus}x}Se{sub x}){sub 3} was hot pressed at 550 C, figure-of-merit increased from 1.14 x 10{sup {minus}3}/K to 1.92 x 10{sup {minus}3}/K with increasing Bi{sub 2}Se{sub 3} content x from 0.05 to 0.15, and then decreased to 1.30 x 10{sup {minus}3}/K for x = 0.25 composition.

  11. Determination of the protective atmosphere during the Pb–Li alloy remelting

    Energy Technology Data Exchange (ETDEWEB)

    Pascual, L., E-mail: laura.pascual@ciemat.es [Ciemat, Madrid (Spain); Barrena, M.I.; Gómez de Salazar, J.M.; Soria, A. [Department of Material Science and Metallurgical Engineering, Faculty of Chemistry, Complutense University of Madrid, Madrid (Spain); Fernández, M.; Conde, E.; Quiñones, J. [Ciemat, Madrid (Spain)

    2014-10-15

    Nuclear fusion technology has been planned as a future massive source of energy. One of the most critical parts of its design is regenerating blanket modules. Among the different materials currently considered for this purpose, we have studied the Pb–Li eutectic alloy. For the production of the eutectic alloy, it is vital to ensure efficient mixing of raw materials, which is hampered by large difference in density of the two components and the high reactivity of Li versus O{sub 2}. This work addressed this issue by presenting a series of tests were made with eutectic ingots in order to determine the composition of protective atmospheres and crucible material. Alloys manufactured were characterized by microscopy and ICP-MS. The results demonstrate that the best crucible material when making mergers is the SiC, due to the low reactivity presented with Pb–Li. Regarding protective atmosphere, Ar BIP (Built-In Purifier) showed the best protection and can be used in a wide range of temperatures and the eutectic salts improve this protection.

  12. A cellular automaton - finite volume method for the simulation of dendritic and eutectic growth in binary alloys using an adaptive mesh refinement

    Science.gov (United States)

    Dobravec, Tadej; Mavrič, Boštjan; Šarler, Božidar

    2017-11-01

    A two-dimensional model to simulate the dendritic and eutectic growth in binary alloys is developed. A cellular automaton method is adopted to track the movement of the solid-liquid interface. The diffusion equation is solved in the solid and liquid phases by using an explicit finite volume method. The computational domain is divided into square cells that can be hierarchically refined or coarsened using an adaptive mesh based on the quadtree algorithm. Such a mesh refines the regions of the domain near the solid-liquid interface, where the highest concentration gradients are observed. In the regions where the lowest concentration gradients are observed the cells are coarsened. The originality of the work is in the novel, adaptive approach to the efficient and accurate solution of the posed multiscale problem. The model is verified and assessed by comparison with the analytical results of the Lipton-Glicksman-Kurz model for the steady growth of a dendrite tip and the Jackson-Hunt model for regular eutectic growth. Several examples of typical microstructures are simulated and the features of the method as well as further developments are discussed.

  13. Investigation of models to predict the corrosion of steels in flowing liquid lead alloys

    International Nuclear Information System (INIS)

    Balbaud-Celerier, F.; Barbier, F.

    2001-01-01

    Corrosion of steels exposed to flowing liquid lead alloys can be affected by hydrodynamic parameters. The rotating cylinder system is of interest for the practical evaluation of the fluid velocity effect on corrosion and for the prediction of the corrosion behavior in other geometries. Models developed in aqueous medium are tested in the case of liquid metal environments. It is shown that equations established for the rotating cylinder and the pipe flow geometry can be used effectively in liquid lead alloys (Pb-17Li) assuming the corrosion process is mass transfer controlled and the diffusion coefficient of dissolved species is known. The corrosion rate of martensitic steels in Pb-17Li is shown to be independent of the geometry when plotted as a function of the mass transfer coefficient. Predictions about the corrosion of steel in liquid Pb-Bi are performed but experiments are needed to validate the results obtained by modeling

  14. Effects of Al-Mn-Ti-P-Cu master alloy on microstructure and properties of Al-25Si alloy

    Directory of Open Access Journals (Sweden)

    Xu Chunxiang

    2013-09-01

    Full Text Available To obtain a higher microstructural refining efficiency, and improve the properties and processing ability of hypereutectic Al-25Si alloy, a new environmentally friendly Al-20.6Mn-12Ti-0.9P-6.1Cu (by wt.% master alloy was fabricated; and its modification and strengthening mechanisms on the Al-25Si alloy were studied. The mechanical properties of the unmodified, modified and heat treated alloys were investigated. Results show that the optimal addition amount of the Al-20.6Mn-12Ti-0.9P-6.1Cu master alloy is 4wt.%. In this case, primary Si and eutectic Si as well as メ-Al phase were clearly refined, and this refining effect shows an excellent long residual action as it can be heat-retained for at least 5 h. After being T6 heat treated, the morphology of primary and eutectic Si in the Al-25Si alloys with the addition of 4wt.% Al-20.6Mn-12Ti-0.9P-6.1Cu alloy changes into particles and short rods. The average grain size of the primary and eutectic Si decreases from 250 レm (unmodified to 13.83 レm and 35 レm (unmodified to 7 レm; the メ-Al becomes obviously finer and the distribution of Si phases tends to be uniform and dispersed. Meanwhile, the tensile properties are improved obviously; the tensile strengths at room temperature and 300 ìC reach 241 MPa and 127 MPa, increased by 153.7% and 67.1%, respectively. In addition, the tensile fracture mechanism changes from brittle fracture for the alloy without modification to ductile fracture after modification. Modifying the morphology of Si phase and strengthening the matrix can effectively block the initiation and propagation of cracks, thus improving the strength of the hypereutectic Al-25Si alloy.

  15. Numerical simulation of heat-transfer and insoluble corrosion product deposition in lead-bismuth eutectic alloy

    International Nuclear Information System (INIS)

    Yang Xu; Zhou Tao; Fang Xiaolu; Lin Daping; Ru Xiaolong

    2015-01-01

    As the primary coolant of ADS (accelerator driven sub-critical system), the safety of reactor will be threatened and the lifetime of the reactor will be shortened by appearing of the tiny particles in LBE (lead-bismuth eutectic) alloy. To this end, numerical simulation with the code of FLUENT was used to research the deposition distribution of insoluble corrosion products in rectangular channel. The standard k-ε model was selected to predict the turbulence variation in the rectangular channel. The discrete phase model (DPM) was used to track the trajectory of the particles. It is found that the deposition efficiency is positively correlated with the temperature difference between the fluid and cold wall. The near wall region with a high concentration of particulate matter and low temperature is in favor of particulate matter deposition on the wall. At the same time, the high turbulence kinetic near wall region is not conducive to the deposition of particulate matter. A secondary flow phenomenon occurs under the influence of boundary wall, namely that there are eight symmetrical regions in the radial direction. (authors)

  16. Development of Pb-rich (Bi, Pb) sub 3 Sr sub 2 Ca sub 2 Cu sub 1 O sub x phase during reformation of lead doped 2223 superconducting phase from melt quenched glass. [BiPbSrCaCuO

    Energy Technology Data Exchange (ETDEWEB)

    Oezkan, N; Glowacki, B A [IRC in Superconductivity, Univ. of Cambridge (United Kingdom)

    1992-05-01

    The reformation process of the lead doped superconducting 2223 phase from the melt quenched glass was investigated. It was shown that during the crystallisation of the glass a new lead rich phase, Bi{sub 0.5}Pb{sub 3}Sr{sub 2}Ca{sub 2}Cu{sub 1}O{sub x}, was formed and severe copper segregation was observed. The volume fraction of the high Tc 2223 phase increased with annealing time for an annealing temperature of 840degC. A glass sample annealed at 840degC for 150 h showed two superconducting transitions Tc = 107 K and Tc = 70 K. (orig.).

  17. The microstructure and coefficient transmission of think films Bi2Te3-xSex, alloyed by terbium

    International Nuclear Information System (INIS)

    Abdullaev, N.M.; Mekhtieva, S.I.; Jalilov, N.Z.; Memmedov, N.R.; Zeynalov, V.Z.

    2007-01-01

    The defects of films microstructures of the thermoelectric materials n- and p-type Bi 2 Te 3 -xSe x , alloyed by Tb and Cl, with think, obtained by thermic evaporation in vacuum have been investigated by microscopic methods

  18. Study of SrBi4Ti4O15 (SBTi) dielectric properties of doped PbO

    International Nuclear Information System (INIS)

    Rodrigues Junior, C.A.; Silva Filho, J.M.; Freitas, D.B.; Oliveira, R.G.M.; Sombra, B.; Sales, J.C.

    2012-01-01

    The ceramic SrBi 4 Ti 4 O 15 (SBTI), cation-deficient perovskite A 5 B 4 O 15 , was prepared by the method of solid state reaction and then doped with PbO (in the range 2-10% by weight). The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and impedance spectroscopy at room temperature. The X-ray analysis was performed by the Rietveld refinement. The micrographs of the samples show globular-shaped grains (doped PbO). The dielectric properties: dielectric constant (Κ' or έ) and dielectric loss tangent (tan δ), were measured at room temperature in the frequency range 100 Hz - 1 MHz dielectric properties of these 1 MHz sample doped with 10 % PbO showed the dielectric constant Κ'= 168.34 and dielectric loss tangent tanδ, = 7,1.10 -2 . These results show a good possibility of miniaturization of electronic devices such as capacitors. (author)

  19. The crystal structure of Cu1.6Pb1.6Bi6.4S12, a new 44.8 Å derivative of the bismuthinite-aikinite solid-solution series

    DEFF Research Database (Denmark)

    Topa, Dan; Balic-Zunic, Tonci; Makovicky, Emil

    2000-01-01

    Cu1.6Pb1.6Bi6.4S12, aikinite-bismuthinite derivative, crystal structure, Felbertal, scheelite deposit, Austria......Cu1.6Pb1.6Bi6.4S12, aikinite-bismuthinite derivative, crystal structure, Felbertal, scheelite deposit, Austria...

  20. Equilibrium phase diagram of the Ag-Au-Pb ternary system

    International Nuclear Information System (INIS)

    Hassam, S.; Bahari, Z.

    2005-01-01

    The phase diagram of the ternary system Ag-Au-Pb has been established using differential thermal analysis and X-ray powder diffraction analysis. Four vertical sections were studied: X Pb = 0.40, X Au /X Pb = 1/3, X Ag /X Au = 4/1 and X Ag /X Au = 1/1. Two ternary transitory peritectics and one ternary eutectic were characterized. A schematic representation of the ternary equilibria is given